Abstract: The rotational stiffness of the zero-stiffness flexible hinge is approximately zero, which overcomes the defect that ordinary flexible hinges require driving torque, and can be applied to flexible grippers and other fields. Taking the inner and outer ring flexible hinges under the action of pure torque as the positive stiffness subsystem, the research Negative stiffness mechanism and matching positive and negative stiffness can construct zero stiffness flexible hinge. Propose a negative stiffness rotation mechanism——Crank spring mechanism, modeled and analyzed its negative stiffness characteristics; by matching positive and negative stiffness, analyzed the influence of structural parameters of crank spring mechanism on zero stiffness quality; proposed a linear spring with customizable stiffness and size——Diamond-shaped leaf spring string, the stiffness model was established and the finite element simulation verification was carried out; finally, the design, processing and testing of a compact zero-stiffness flexible hinge sample were completed. The test results showed that: under the action of pure torque,±18°In the range of rotation angles, the rotational stiffness of the zero-stiffness flexible hinge is 93% lower than that of the inner and outer ring flexible hinges on average. The constructed zero-stiffness flexible hinge has a compact structure and high-quality zero-stiffness; the proposed negative-stiffness rotation mechanism and the linear The spring has great reference value for the study of flexible mechanism.

0 Preface

Flexible hinge (bearing)

^[1-2]

Relying on the elastic deformation of the flexible unit to transmit or convert motion, force and energy, it has been widely used in precision positioning and other fields. Compared with traditional rigid bearings, there is a restoring moment when the flexible hinge rotates. Therefore, the drive unit needs to provide output torque to drive and Keep the rotation of the flexible hinge. Zero stiffness flexible hinge

^[3]

(Zero stiffness flexural pivot, ZSFP) is a flexible rotary joint whose rotational stiffness is approximately zero. This type of flexible hinge can stay at any position within the stroke range, also known as static balance flexible hinge

^[4]

, are mostly used in fields such as flexible grippers.

Based on the modular design concept of the flexible mechanism, the entire zero-stiffness flexible hinge system can be divided into two subsystems of positive and negative stiffness, and the zero-stiffness system can be realized through the matching of positive and negative stiffness

^[5]

. Among them, the positive stiffness subsystem is usually a large-stroke flexible hinge, such as a cross-reed flexible hinge

^[6-7]

, generalized three-cross reed flexible hinge

^[8-9]

and inner and outer ring flexible hinges

^[10-11]

etc. At present, the research on flexible hinges has achieved a lot of results, therefore, the key to design zero-stiffness flexible hinges is to match suitable negative stiffness modules for flexible hinges[3].

Inner and outer ring flexible hinges (Inner and outer ring flexural pivots, IORFP) have excellent characteristics in terms of stiffness, precision and temperature drift. The matching negative stiffness module provides the construction method of the zero-stiffness flexible hinge, and finally, completes the design, sample processing and testing of the zero-stiffness flexible hinge.

1 crank spring mechanism

1.1 Definition of negative stiffness

The general definition of stiffness K is the rate of change between the load F borne by the elastic element and the corresponding deformation dx

K= dF/dx (1)

When the load increment of the elastic element is opposite to the sign of the corresponding deformation increment, it is negative stiffness. Physically, the negative stiffness corresponds to the static instability of the elastic element

^[12]

.Negative stiffness mechanisms play an important role in the field of flexible static balance. Usually, negative stiffness mechanisms have the following characteristics.

(1) The mechanism reserves a certain amount of energy or undergoes a certain deformation.

(2) The mechanism is in a critical instability state.

(3) When the mechanism is slightly disturbed and leaves the equilibrium position, it can release a larger force, which is in the same direction as the movement.

1.2 Construction principle of zero-stiffness flexible hinge

The zero-stiffness flexible hinge can be constructed by using positive and negative stiffness matching, and the principle is shown in Figure 2.

(1) Under the action of pure torque, the inner and outer ring flexible hinges have an approximately linear torque-rotation angle relationship, as shown in Figure 2a. Especially, when the intersection point is located at 12.73% of the reed length, the torque-rotation angle relationship is linear

^[11]

, at this time, the restoring moment Mpivot (clockwise direction) of the flexible hinge is related to the bearing rotation angleθ(counterclockwise) the relationship is

Mpivot=(8EI/L)θ (2)

In the formula, E is the elastic modulus of the material, L is the length of the reed, and I is the moment of inertia of the section.

(2) According to the rotational stiffness model of the inner and outer ring flexible hinges, the negative stiffness rotating mechanism is matched, and its negative stiffness characteristics are shown in Figure 2b.

(3) In view of the instability of the negative stiffness mechanism

^[12]

, the stiffness of the zero-stiffness flexible hinge should be approximately zero and greater than zero, as shown in Figure 2c.

1.3 Definition of crank spring mechanism

According to literature [4], a zero-stiffness flexible hinge can be constructed by introducing a pre-deformed spring between the moving rigid body and the fixed rigid body of the flexible hinge. For the inner and outer ring flexible hinge shown in FIG. 1, a spring is introduced between the inner ring and the outer ring, I .e., a spring-crank mechanisms (SCM) is introduced. Referring to the crank slider mechanism shown in Figure 3, the related parameters of the crank spring mechanism are shown in Figure 4. The crank-spring mechanism is composed of a crank and a spring (set stiffness as k). the initial angle is the included angle between the crank AB and the base AC when the spring is not deformed. R represents the crank length, l represents the base length, and defines the crank length ratio as the ratio of r to l, I .e. = r/l (0<<1).

The construction of the crank-spring mechanism requires the determination of 4 parameters: the base length l, the crank length ratio , the initial angle and the spring stiffness K.

The deformation of the crank spring mechanism under force is shown in Figure 5a, at the moment M

_γ

Under the action, the crank moves from the initial position AB

_Beta

turn to AB

_γ

, during the rotation process, the included angle of the crank relative to the horizontal position

_γ

called the crank angle.

Qualitative analysis shows that the crank rotates from AB (initial position, M & gamma; Zero) to AB0 (“dead point”location, M

_γ

is zero), the crank-spring mechanism has a deformation with negative stiffness characteristics.

1.4 The relationship between torque and rotation angle of crank spring mechanism

In Fig. 5, the torque M & gamma; clockwise is positive, the crank angle & gamma; counterclockwise is positive, and the moment load M is modeled and analyzed below.

_γ

with crank angle

_γ

The relationship between the modeling process is dimensioned.

As shown in Figure 5b, the torque balance equation for crank AB & gamma is listed.

In the formula, F & gamma; is the spring restoring force, d & gamma; is F & gamma; to point A. Assume that the displacement-load relation of the spring is

In the formula, K is the spring stiffness (not necessarily a constant value),δ

xγ

is the amount of spring deformation (shortened to positive),δ

xγ

=|B

_Beta

C| – |B

_γ

C|.

Simultaneous type (3)(5), moment M

_γ

with corner

_γ

The relationship is

1.5 Analysis of the negative stiffness characteristics of the crank-spring mechanism

In order to facilitate the analysis of the negative stiffness characteristics of the crank-spring mechanism (moment M

_γ

with corner

_γ

relationship), it may be assumed that the spring has a linear positive stiffness, then formula (4) can be rewritten as

In the formula, Kconst is a constant greater than zero. After the size of the flexible hinge is determined, the length l of the base is also determined. Therefore, assuming that l is a constant, formula (6) can be rewritten as

where Kconstl2 is a constant greater than zero, and the moment coefficient m & gamma; has a dimension of one. The negative stiffness characteristics of the crank-spring mechanism can be obtained by analyzing the relationship between the torque coefficient m & gamma; and the rotation angle & gamma.

From equation (9), Figure 6 shows the initial angle =π relationship between m & gamma; and crank length ratio and rotation angle & gamma;, & isin;[0.1, 0.9],& gamma;& isin;[0, π]. Figure 7 shows the relationship between m & gamma; and rotation angle & gamma; for = 0.2 and different . Figure 8 shows =π When, under different , the relationship between m & gamma; and angle & gamma.

According to the definition of crank spring mechanism (section 1.3) and formula (9), when k and l are constant, m & gamma; Only related to angle & gamma;, crank length ratio and crank initial angle .

(1) If and only if & gamma; is equal to 0 orπ or ,m & gamma; is equal to zero; & gamma; & isin;[0, ],m & gamma; is greater than zero; & gamma; & isin;[,π],m & gamma; less than zero. & isin;[0, ],m & gamma; is greater than zero; & gamma;& isin;[,π],m & gamma; less than zero.

(2) & gamma; When [0, ], the rotation angle & gamma; increases, m & gamma; increases from zero to the inflection point angle & gamma;0 takes the maximum value m & gamma;max, and then gradually decreases.

(3) The negative stiffness characteristic range of the crank spring mechanism: & gamma;& isin;[0, & gamma;0], at this time & gamma; increases (counterclockwise), and the torque M & gamma; increases (clockwise). The inflection point angle & gamma;0 is the maximum rotation angle of the negative stiffness characteristic of the crank-spring mechanism and & gamma;0 & isin;[0, ];m & gamma;max is the maximum negative moment coefficient. Given and , the derivation of equation (9) yields & gamma;0

(4) the larger the initial angle , & gamma; the larger 0, m

_γmax

bigger.

(5) the larger the length ratio , & gamma; the smaller 0, m

_γmax

bigger.

In particular, =πThe negative stiffness characteristics of the crank spring mechanism are the best (the negative stiffness angle range is large, and the torque that can be provided is large). =πAt the same time, under different conditions, the maximum rotation angle & gamma of the negative stiffness characteristic of the crank spring mechanism; 0 and the maximum negative torque coefficient m & gamma; Max is listed in table 1.

2 Construction of zero-stiffness flexible hinge

The matching of positive and negative stiffness of the 2.1 is shown in Figure 9, n(n 2) groups of parallel crank spring mechanisms are evenly distributed around the circumference, forming a negative stiffness mechanism matched with the inner and outer ring flexible hinges.

Using the inner and outer ring flexible hinges as the positive stiffness subsystem, construct a zero-stiffness flexible hinge. In order to achieve zero stiffness, match the positive and negative stiffness

simultaneous (2), (3), (6), (11), and & gamma;=θ, the load F & gamma of the spring can be obtained; and displacementδThe relationship of x & gamma; is

According to section 1.5, the negative stiffness angle range of the crank spring mechanism: & gamma;& isin;[0, & gamma;0] and & gamma;0 & isin;[0, ], the stroke of the zero stiffness flexible hinge shall be less than & gamma;0, I .e. the spring is always in a deformed state (δxγ≠0). The rotation range of the inner and outer ring flexible hinges is±0.35 rad(±20°), simplify the trigonometric functions sin & gamma; and cos & gamma; as follows

After simplification, the load-displacement relationship of the spring

2.2 Error analysis of positive and negative stiffness matching model

Evaluate the error caused by the simplified treatment of equation (13). According to the actual processing parameters of zero stiffness flexible hinge (Section 4.2):n = 3,l = 40mm, =π, = 0.2,E = 73 GPa; The dimensions of the inner and outer ring flexible hinge reed L = 46mm,T = 0.3mm,W = 9.4mm; The comparison formulas (12) and (14) simplify the load displacement relationship and relative error of the front and rear springs as shown in Figures 10a and 10b respectively.

As shown in Figure 10, & gamma; is less than 0.35 rad (20°), the relative error caused by the simplified treatment to the load-displacement curve does not exceed 2.0%, and the formula

The simplified treatment of (13) can be used to construct zero-stiffness flexible hinges.

2.3 Stiffness characteristics of the spring

Assuming the stiffness of the spring is K, the simultaneous (3), (6), (14)

According to the actual processing parameters of zero stiffness flexible hinge (Section 4.2), the change curve of spring stiffness K with angle & gamma; is shown in Figure 11. In particular, when & gamma;= 0, K takes the minimum value.

For the convenience of design and processing, the spring adopts a linear positive stiffness spring, and the stiffness is Kconst. In the whole stroke, if the total stiffness of the zero stiffness flexible hinge is greater than or equal to zero, Kconst should take the minimum value of K

Equation (16) is the stiffness value of the linear positive stiffness spring when constructing the zero stiffness flexible hinge. 2.4 Analysis of zero-stiffness quality The load-displacement relationship of the constructed zero-stiffness flexible hinge is

Simultaneous formula (2), (8), (16) can be obtained

In order to evaluate the quality of zero stiffness, the reduction range of flexible hinge stiffness before and after adding the negative stiffness module is defined as the zero stiffness quality coefficientη

η The closer to 100%, the higher the quality of zero stiffness. Figure 12 is 1-η Relationship with crank length ratio and initial angle η It is independent of the number n of parallel crank-spring mechanisms and the length l of the base, but only related to the crank length ratio , the rotation angle & gamma; and the initial angle .

(1) The initial angle increases and the zero stiffness quality improves.

(2) The length ratio increases and the zero stiffness quality decreases.

(3) Angle & gamma; increases, zero stiffness quality decreases.

In order to improve the zero stiffness quality of the zero stiffness flexible hinge, the initial angle should take a larger value; the crank length ratio should be as small as possible. At the same time, according to the analysis results in Section 1.5, if is too small, the ability of the crank-spring mechanism to provide negative stiffness will be weak. In order to improve the zero stiffness quality of the zero stiffness flexible hinge, the initial angle =π, crank length ratio = 0.2, that is, the actual processing parameters of section 4.2 zero stiffness flexible hinge.

According to the actual processing parameters of the zero-stiffness flexible hinge (Section 4.2), the torque-angle relationship between the inner and outer ring flexible hinges and the zero-stiffness flexible hinge is shown in Figure 13; the decrease in stiffness is the zero-stiffness quality coefficientηThe relationship with the corner & gamma; is shown in Figure 14. By Figure 14: In 0.35 rad (20°) rotation range, the stiffness of the zero-stiffness flexible hinge is reduced by an average of 97%; 0.26 rad(15°) corners, it is reduced by 95%.

3 Design of linear positive stiffness spring

The construction of zero stiffness flexible hinge is usually after the size and stiffness of the flexible hinge are determined, and then the stiffness of the spring in the crank spring mechanism is reversed, so the stiffness and size requirements of the spring are relatively strict. In addition, the initial angle =π, from Figure 5a, during the rotation of the zero-stiffness flexible hinge, the spring is always in a compressed state, that is“Compression spring”.

The stiffness and size of traditional compression springs are difficult to customize precisely, and a guide mechanism is often required in applications. Therefore, a spring whose stiffness and size can be customized is proposed——Diamond-shaped leaf spring string. The diamond-shaped leaf spring string (Figure 15) is composed of multiple diamond-shaped leaf springs connected in series. It has the characteristics of free structural design and high degree of customization. Its processing technology is consistent with that of flexible hinges, and both are processed by precision wire cutting.

3.1 Load-displacement model of diamond-shaped leaf spring string

Due to the symmetry of the rhombic leaf spring, only one leaf spring needs to be subjected to stress analysis, as shown in Figure 16. α is the angle between the reed and the horizontal, the length, width and thickness of the reed are Ld, Wd, Td respectively, f is the dimensionally unified load on the rhombus leaf spring,δy is the deformation of rhombic leaf spring in the y direction, force fy and moment m are equivalent loads on the end of a single reed, fv and fw are component forces of fy in the wov coordinate system.

According to the beam deformation theory of AWTAR[13], the dimensionally unified load-displacement relation of single reed

Due to the constraint relationship of the rigid body on the reed, the end angle of the reed before and after deformation is zero, that isθ = 0. Simultaneous (20)(22)

Equation (23) is the load-displacement dimensional unification model of rhombic leaf spring. n2 rhombic leaf springs are connected in series, and its load-displacement model is

From formula (24), whenαWhen d is small, the stiffness of the diamond-shaped leaf spring string is approximately linear under typical dimensions and typical loads.

3.2 Finite element simulation verification of the model

The finite element simulation verification of the load-displacement model of the diamond-shaped leaf spring is carried out. Using ANSYS Mechanical APDL 15.0, the simulation parameters are shown in Table 2, and a pressure of 8 N is applied to the diamond-shaped leaf spring.

The comparison between the model results and the simulation results of the rhombus leaf spring load-displacement relationship is shown in Fig. 17 (dimensionalization). For four rhombus leaf springs with different inclination angles, the relative error between the model and the finite element simulation results does not exceed 1.5%. The validity and accuracy of the model (24) has been verified.

4 Design and test of zero-stiffness flexible hinge

4.1 Parameter design of zero-stiffness flexible hinge

To design a zero-stiffness flexible hinge, the design parameters of the flexible hinge should be determined according to the service conditions first, and then the relevant parameters of the crank spring mechanism should be calculated inversely.

4.1.1 Flexible hinge parameters

The intersection point of the inner and outer ring flexible hinges is located at 12.73% of the reed length, and its parameters are shown in Table 3. Substituting into equation (2), the torque-rotation angle relationship of the inner and outer ring flexible hinges is

4.1.2 Negative stiffness mechanism parameters

As shown in fig. 18, taking the number n of crank spring mechanisms in parallel as 3, the length l = 40 mm is determined by the size of the flexible hinge. according to the conclusion of section 2.4, the initial angle =π, crank length ratio = 0.2. According to equation (16), the stiffness of the spring (I .e. diamond leaf spring string) is Kconst = 558.81 N/m (26)

4.1.3 Diamond leaf spring string parameters

by l = 40mm, =π, = 0.2, the original length of the spring is 48mm, and the maximum deformation (& gamma;= 0) is 16mm. Due to structural limitations, it is difficult for a single rhombus leaf spring to produce such a large deformation. Using four rhombus leaf springs in series (n2 = 4), the stiffness of a single rhombus leaf spring is

Kd=4Kconst=2235.2 N/m (27)

According to the size of the negative stiffness mechanism (Figure 18), given the reed length, width and reed inclination angle of the diamond-shaped leaf spring, the reed can be deduced from formula (23) and the stiffness formula (27) of the diamond-shaped leaf spring Thickness. The structural parameters of rhombus leaf springs are listed in Table 4.

surface4

In summary, the parameters of the zero-stiffness flexible hinge based on the crank spring mechanism have all been determined, as shown in Table 3 and Table 4.

4.2 Design and processing of the zero-stiffness flexible hinge sample Refer to literature [8] for the processing and testing method of the flexible hinge. The zero-stiffness flexible hinge is composed of a negative stiffness mechanism and an inner and outer ring flexible hinge in parallel. The structural design is shown in Figure 19.

Both the inner and outer ring flexible hinges and diamond-shaped leaf spring strings are processed by precision wire-cutting machine tools. The inner and outer ring flexible hinges are processed and assembled in layers. Figure 20 is the physical picture of three sets of diamond-shaped leaf spring strings, and Figure 21 is the assembled zero-stiffness The physical picture of the flexible hinge sample.

4.3 The rotational stiffness test platform of the zero-stiffness flexible hinge Referring to the rotational stiffness test method in [8], the rotational stiffness test platform of the zero-stiffness flexible hinge is built, as shown in Figure 22.

4.4 Experimental data processing and error analysis

The rotational stiffness of the inner and outer ring flexible hinges and zero-stiffness flexible hinges was tested on the test platform, and the test results are shown in Figure 23. Calculate and draw the zero-stiffness quality curve of the zero-stiffness flexible hinge according to formula (19), as shown in Fig. 24.

The test results show that the rotational stiffness of the zero-stiffness flexible hinge is close to zero. Compared with the inner and outer ring flexible hinges, the zero-stiffness flexible hinge±0.31 rad(18°) stiffness was reduced by an average of 93%; 0.26 rad (15°), the stiffness is reduced by 90%.

As shown in Figures 23 and 24, there is still a certain gap between the test results of the zero stiffness quality and the theoretical model results (the relative error is less than 15%), and the main reasons for the error are as follows.

(1) The model error caused by the simplification of trigonometric functions.

(2) Friction. There is friction between the diamond leaf spring string and the mounting shaft.

(3) Processing error. There are errors in the actual size of the reed, etc.

(4) Assembly error. The gap between the installation hole of the diamond-shaped leaf spring string and the shaft, the installation gap of the test platform device, etc.

4.5 Performance comparison with a typical zero-stiffness flexible hinge In literature [4], a zero-stiffness flexible hinge ZSFP_CAFP was constructed using a cross-axis flexural pivot (CAFP), as shown in Figure 25.

Comparison of the zero-stiffness flexible hinge ZSFP_IORFP (Fig. 21) and ZSFP_CAFP (Fig. 25) constructed using the inner and outer ring flexible hinges

(1) ZSFP_IORFP, the structure is more compact.

(2) The corner range of ZSFP_IORFP is small. The corner range is limited by the corner range of the flexible hinge itself; the corner range of ZSFP_CAFP80°, ZSFP_IORFP corner range40°.

(3) ±18°In the range of corners, ZSFP_IORFP has higher quality of zero stiffness. The average stiffness of ZSFP_CAFP is reduced by 87%, and the average stiffness of ZSFP_IORFP is reduced by 93%.

5 Conclusion

Taking the flexible hinge of the inner and outer rings under pure torque as the positive stiffness subsystem, the following work has been done in order to construct a zero-stiffness flexible hinge.

(1) Propose a negative stiffness rotation mechanism——For the crank spring mechanism, a model (Formula (6)) was established to analyze the influence of structural parameters on its negative stiffness characteristics, and the range of its negative stiffness characteristics was given (Table 1).

(2) By matching the positive and negative stiffnesses, the stiffness characteristics of the spring in the crank spring mechanism (Equation (16)) are obtained, and the model (Equation (19)) is established to analyze the effect of the structural parameters of the crank spring mechanism on the zero stiffness quality of the zero stiffness flexible hinge Influence, theoretically, within the available stroke of the flexible hinge of the inner and outer rings (±20°), the average reduction in stiffness can reach 97%.

(3) Propose a customizable stiffness“spring”——A diamond-shaped leaf spring string was established to establish its stiffness model (Equation (23)) and verified by finite element method.

(4) Completed the design, processing and testing of a compact zero-stiffness flexible hinge sample. The test results show that: under the action of pure torque, the36°In the range of rotation angles, compared with the inner and outer ring flexible hinges, the stiffness of the zero-stiffness flexible hinge is reduced by 93% on average.

The constructed zero-stiffness flexible hinge is only under the action of pure torque, which can realize“zero stiffness”, without considering the case of bearing complex loading conditions. Therefore, the construction of zero-stiffness flexible hinges under complex load conditions is the focus of further research. In addition, reducing the friction that exists during the movement of zero-stiffness flexible hinges is an important optimization direction for zero-stiffness flexible hinges.

references

[1] HOWELL L L. Compliant Mechanisms[M]. New York: John Wiley&Sons, Inc, 2001.

[2] Yu Jingjun, Pei Xu, Bi Shusheng, etc. Research progress on design methods of flexible hinge mechanism[J]. Chinese Journal of Mechanical Engineering, 2010, 46(13):2-13. Y u jin champion, PEI X U, BIS call, ETA up. State-of-arts of Design Method for Flexure Mechanisms[J]. Journal of Mechanical Engineering, 2010, 46(13):2-13.

[3] MORSCH F M, Herder J L. Design of a Generic Zero Stiffness Compliant Joint[C]// ASME International Design Engineering Conferences. 2010:427-435.

[4] MERRIAM E G, Howell L L. Non-dimensional approach for static balancing of rotational flexures[J]. Mechanism & Machine Theory, 2015, 84(84):90-98.

[5] HOETMER K, Woo G, Kim C, et al. Negative Stiffness Building Blocks for Statically Balanced Compliant Mechanisms: Design and Testing[J]. Journal of Mechanisms & Robotics, 2010, 2(4):041007.

[6] JENSEN B D, Howell L L. The modeling of cross-axis flexural pivots[J]. Mechanism and machine theory, 2002, 37(5):461-476.

[7] WITTRICK W H. The properties of crossed flexure pivots and the influence of the point at which the strips cross[J]. The Aeronautical Quarterly, 1951, II: 272-292.

[8] l IU l, BIS, yang Q, ETA. Design and experiment of generalized triple-cross-spring flexure pivots applied to the ultra-precision instruments[J]. Review of Scientific Instruments, 2014, 85(10): 105102.

[9] Yang Qizi, Liu Lang, Bi Shusheng, etc. Research on rotational stiffness characteristics of generalized three-cross reed flexible hinge[J]. Chinese Journal of Mechanical Engineering, 2015, 51(13): 189-195.

yang Q I word, l IU Lang, BIS voice, ETA. Rotational Stiffness Characterization of Generalized Triple-cross-spring Flexure Pivots[J]. Journal of Mechanical Engineering, 2015, 51(13):189-195.

[10] l IU l, Zhao H, BIS, ETA. Research of Performance Comparison of Topology Structure of Cross-Spring Flexural Pivots[C]// ASME 2014 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, August 17–20, 2014, Buffalo, New York, USA. ASME, 2014 : V05AT08A025.

[11] l IU l, BIS, yang Q. Stiffness characteristics of inner–outer ring flexure pivots applied to the ultra-precision instruments[J]. ARCHIVE Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science 1989-1996 (vols 203-210), 2017:095440621772172.

[12] SANCHEZ J A G. Criteria for the Static Balancing of Compliant Mechanisms[C]// ASME 2010 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, August 15–18, 2010, Montreal, Quebec, Canada. ASME, 2010:465-473.

[13] AWTAR S, Sen S. A generalized constraint model for two-dimensional beam flexures: Nonlinear strain energy formulation[J]. Journal of Mechanical Design, 2010, 132: 81009.

About the author: Bi Shusheng (corresponding author), male, born in 1966, doctor, professor, doctoral supervisor. His main research direction is fully flexible mechanism and bionic robot.

What kind of better wardrobe sliding door track is there?

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After separating the pulley, do not turn the direction of the pulley, you will find a small track on the top of the sliding door, this is the problem of failure, try to use the method to fix the door, and then install it back according to the original method.

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2. Matters needing attention in the installation of wardrobe sliding door slide rails

1. The sliding door is in contact with the wall or both sides of the cabinet body. At the contact position, there should be no other objects blocking the closing of the sliding door.

2. The position of the drawer in the cabinet should avoid the intersection of sliding doors, and it should be 1 cm higher than the bottom plate; the drawer in the folding door cabinet should be at least 15 cm away from the side wall, pay attention to the power switch and socket on the wall, if it is blocked When the sliding door is closed, its position should be modified in time accordingly.

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The second hardware accessories pulleys and guide rails

In addition to plates, custom-made furniture is hardware, plates account for a large proportion, but the role of hardware is also the finishing touch. The quality of hardware directly affects the life of furniture. There are far more types of hardware than plates in the market. Many, today we take a look at one of the wardrobe hardware sliding door pulleys rollers and rails.

The pulleys and guide rails in the sliding door wardrobe are the most frequently used accessories, so their quality directly affects the service life of the wardrobe. The quality is also uneven on the market, and there are all kinds of prices. So what exactly should it have? Functions and materials can meet the needs of the public.

The track of the sliding door can be roughly divided into: two directions can be pushed and pulled, one-way push and pull and folding style, customers can choose according to the actual situation.

The pulley in the sliding door track pulley is a very important accessory in the sliding door. When purchasing, you must know what your material is. The current pulley material is divided into three types: plastic pulley, which is hard but fragile. Use After a period of time, the sliding door will not be smooth; the quality of the metal pulley is better, but the noise is very loud; the glass pulley is the best of these three pulleys, with excellent toughness and wear resistance, and it is very convenient to push and pull , and has a long service life.

Sliding door guide rails are more important for sliding doors. Different material quality affects the different quality and use effect of sliding doors, and the service life of high-quality sliding door materials will be longer. The most important thing for the track is whether it can be compatible with The pulley fits perfectly and the size is just right. This is the most important thing. Such a sliding door slides smoothly, has good shock absorption and noise resistance, and has a better mute effect. When consumers choose sliding door rails, they must To choose a good quality guide rail suitable for your house type, choose a guide rail that is wear-resistant, not easy to deform, and has a good push-pull feel.

For other details, whether the guide rails and pulleys are easy to clean, whether they are quiet, whether there are locks and internal structures, whether they are resistant to high temperature and oxidation should be asked clearly. What is the size of the track of the wardrobe sliding door?

The general sliding door track is 84mm, and the generally reserved position is 100mm. Now there is a track width of 70mm, but the sliding door frame corresponding to this track is also matched.

The height of the door is preferably above 207 cm, so that the whole room will not appear too depressing. The best sliding door track size is about 80 cm by 200 cm, so that the height of the door is very stable and looks good.

Consumers should know which tracks are available before knowing the size of the sliding door track. The track of the sliding door can be roughly divided into: the track that can be pushed and pulled in two directions, the one-way and the folding sliding door. Among these three kinds, the folding sliding door The door will save space. If the consumer chooses to make a sliding door, the height of the door should be selected above 207 cm, so that the whole room will not appear too depressing. The best sliding door track size is 80 cm x With a height of about 200 cm, the door is very stable and looks good.

Of course, there are also many large houses (decoration renderings of large houses). If these consumers want to make a very high sliding door track size, they should pay attention to it, because the door is very high, and if it is often pushed and pulled, the door itself will be damaged. If it is too high, it will be unstable, and it will be more likely to cause the door to fall off. If some sliding doors are well done, it can make people visually see that the room becomes larger, for example, in the kitchen (kitchen decoration renderings) ) using the open sliding door, which not only has the treatment of partition (partition decoration renderings), but also makes the whole space bigger. Therefore, consumers should pay more attention to the choice of sliding door materials. Sliding doors of different materials have different effects, but it is best not to choose fully transparent glass, which is prone to light pollution.

There are three types of pulleys on the market: plastic pulleys, metal pulleys and fiberglass pulleys. For example, some big brands like Meizhixuan doors and windows use carbon fiberglass pulleys.

1. The metal pulley has a very strong load-bearing capacity, and can withstand great frictional strength and pressure, and is not easy to deform.

2. The rubber wheel is made of carbon fiberglass or nylon material, which can make the push and pull activities very smooth, and it is not easy to make harsh friction sounds.

3. Glass fiber rollers, this material is the most common in the use of wardrobe sliding doors, because it is not easy to deform, and the sliding is also very smooth.

Extended information:

Fiberglass pulleys are good. At present, there are generally two types of pulleys on the market: plastic pulleys and fiberglass pulleys. Plastic pulleys are hard, but they are easy to break. After a long time of use, they will become astringent, and the push-pull feeling will become very poor. The price It is also cheaper; the fiberglass pulley has good toughness, wear resistance, smooth sliding, and durability. When purchasing, be sure to recognize the material of the pulley.

Matters needing attention in the installation of wardrobe sliding door track

Nowadays, all families like to customize wardrobes. As the facade of the wardrobe, the sliding door is the most intuitive factor affecting the overall style and appearance of the wardrobe, and the sliding door is also one of the wardrobe parts that are most likely to come into contact with the human body and objects in real life. For Many consumers have some confusion about the installation of wardrobe sliding doors. The core of the installation of wardrobe sliding doors lies in the installation of tracks. Therefore, let me introduce to you next.

Wardrobe sliding door track installation

Detailed explanation.

The sliding door track is the core component of the sliding door. The most important thing to install the sliding door is

Wardrobe sliding door track installation

, the track installation is almost complete.

1. The size of the track box on the upper part of the sliding door should be 12 cm high and 9 cm wide. Like a curtain box, a track is installed in the track box, and the sliding door can be hung on the track. When the height of the door is lower than 1.95 meters, It makes people feel depressed. Therefore, when making a sliding door, the height should be at least 19512=207 cm or more.

2. The golden size of a normal door is about 80 cm 200 cm. Under this structure, the door is relatively stable and beautiful. Therefore, the ratio of the width to the height of the sliding door should be similar to the golden size.

3. Use with caution the sliding door from the floor to the top (open track box). Due to the excessive swing when pushing and pulling, the sliding door is easy to deform over time. After deformation, the door cannot be opened, which means it cannot be repaired and cannot be used.

4. Finally, install the sliding door track: fix the upper track, hang 3 points on the two ends and the middle point of the upper track with a gravity cone (suspension hammer), draw a 3.3-point fixed surface on the ground with an oil pen, install the upper track, and then Put a hanging hammer on the ground against the center point of the upper track, put vertical lines on both ends of the track, and fix the lower track on these 3 points so as to ensure that the upper and lower tracks are completely parallel, and the sliding door is in the best position. status.

to guarantee

Wardrobe sliding door track installation

The smooth progress, need to pay attention to the following points

1. Since the sliding door is in contact with the wall or both sides of the cabinet body, there should be no other objects blocking the closing of the sliding door at the contact position. For example, the position of the drawer in the cabinet should avoid the intersection of sliding doors and be higher than the bottom plate At least 1cm; the drawer in the folding door cabinet is at least 15cm away from the side wall. Here, pay special attention to the power switch and socket on the wall. If the closing of the sliding door is blocked, the position of the switch and socket should be changed.

2. No matter what material you make on the ground, you must ensure that it is level, and the four walls of the door opening must also be kept horizontal and vertical. Otherwise, the door will be skewed after installation. The adjustable error is not greater than 10mm.

3. Please do not install the corner line at the installation position. The gypsum line can be installed on the sealing plate above the closet. If the door is directly to the top, do not install the gypsum line. For carpets with a thickness of less than 5 mm, cut off the carpet at the location and paste it directly If the carpet with a thickness of more than 5 mm is installed on the lower rail, it can be directly fixed on the carpet with screws; if it is installed with a single rail, the carpet at the position must be cut off, and a 3-5 mm thick wooden strip is placed on the carpet in advance, so that The monorail is pasted directly on top.

Finally, a warm reminder,

wardrobe sliding door track

It's important, so we're doing

Wardrobe sliding door track installation

It is better to be more cautious. I hope that the wardrobe sliding door track installation I introduced today will be helpful to everyone.

What are the installation steps of sliding door wardrobe

Wardrobe sliding door slide installation steps;

1. The size of the track box on the upper part of the sliding door must be 12 cm high and 9 cm wide. Like a curtain box, a track is installed in the track box, and the sliding door can be hung on the track. When the height of the door is lower than 1.95 meters, It makes people feel very depressed. Therefore, when making a sliding door, the height should be at least 19512=207 cm.

2. The golden size of a normal door is about 80 cm x 200 cm. Under this structure, the door is relatively stable and beautiful at the same time. Therefore, the ratio of the width to the height of the sliding door should be similar to the golden size.

3. Use the sliding door from the floor to the top with caution (open track box). Due to the excessive swing when pushing and pulling, the sliding door is easy to deform over time. After deformation, the door cannot be opened, which means it cannot be repaired and cannot be used.

4. When installing the sliding door track, fix the upper track, hang 3 points on the two ends and the midpoint of the upper track with a gravity cone (hanging hammer) and draw a 3.3-point fixed surface on the ground with an oil pen, install the upper track, and then Put a hanging hammer to the ground at the center of the upper track, put vertical lines at both ends of the track, and fix the lower track at these three points to ensure that the upper and lower tracks are completely parallel, and the sliding door is in the best state. up.