CN113107959B - Spiral flexible hinge - Google Patents

Abstract

The invention discloses a spiral flexible hinge. It includes at least one spiral flexible hinge unit, spiral flexible hinge unit includes first driving medium, the intermediate drive spare, the second driving medium, first spiral spare, the second spiral spare, first spiral spare and second spiral spare structure are the same, it forms to close by at least two spiral spring convolutions that revolve to the same, the convolution of the spiral spring of first spiral spare is opposite with the convolution of the spiral spring of second spiral spare, the one end and the first driving medium of first spiral spare are connected, the other end and the one end of intermediate drive spare of first spiral spare are connected, the one end and the other end of intermediate drive spare of second spiral spare are connected, the other end and the second driving medium of second spiral spare are connected, first driving medium, first spiral spare, the intermediate drive spare, the second spiral spare, the second driving medium coaxial line sets up. The invention can realize large-angle rotation, has small shaft drift, can meet the requirements of flexibility and precision, and can meet the requirements of large stroke and high precision.

Description

A spiral flexible hinge

technical field

The invention relates to a spiral flexible hinge, belonging to the technical field of hinges.

Background technique

With the continuous expansion of the application range of flexible hinges, the problems of flexibility and accuracy of traditional flexible hinges in the technical application process are significant. There is a problem of a small range of rotation angles in terms of flexibility, and there is a problem of axis drift in terms of accuracy. These defects affect the application of flexible hinges, especially in applications with large strokes, the shaft drift problem of traditional flexible hinges is more prominent, and it is difficult to meet the requirements of high precision.

In robotics and other technical fields, in order to meet the requirements of large stroke and high precision, it is necessary to adopt flexible hinges that can realize larger turning angles and zero drift, and the existing flexible hinges cannot meet the requirements. In order to solve the demand for a large stroke and high precision flexible hinge, the present invention proposes a new flexible hinge.

SUMMARY OF THE INVENTION

In view of the above-mentioned defects in the prior art, the present invention provides a flexible hinge that can realize a large rotation angle and a small shaft drift.

The present invention is achieved through the following technical solutions: a spiral flexible hinge, characterized in that it includes at least one spiral flexible hinge unit, and the spiral flexible hinge unit includes a first transmission member, an intermediate transmission member, a second transmission member, and a second transmission member. The transmission member, the first helical member, and the second helical member, the first helical member and the second helical member have the same structure and are formed by at least two helical springs with the same rotation direction. The direction of rotation of the coil spring of the second coil is opposite to that of the coil spring of the second coil. One end of the first coil is connected to the first transmission part, and the other end of the first coil is connected to the first transmission part. One end of the intermediate transmission member is connected, one end of the second screw member is connected with the other end of the intermediate transmission member, the other end of the second screw member is connected with the second transmission member, the first transmission member, The first screw member, the intermediate transmission member, the second screw member, and the second transmission member are arranged coaxially.

The coil spring will deform when subjected to a bending moment, that is, when subjected to a bending moment, the coil spring will expand or contract. For a single coil spring, when subjected to a bending moment, the center axis drift and axial displacement will occur, and the center axis drift will also change due to the different position of the force point of the coil spring. According to the experiment, when two identical coil springs are subjected to the same bending moment, when the positions of the force points are opposite, the values of the central axis drift are opposite. Therefore, after the two coil springs are screwed together to form a coil, when the two coil springs are subjected to the same bending moment, the center axis drift generated by the two coil springs will cancel each other, so that the center axis drift of the coil is At this time, the screw still has axial displacement, that is, when the screw expands or contracts due to the action of bending moment, it will expand or compress in the axial direction, resulting in axial displacement. When two helical parts with opposite helical directions are coaxially connected, under the action of the same bending moment, the axial displacements produced by the two helical parts are opposite, and the axial displacements produced by the two cancel each other out, so that the overall realization of the connecting part is realized. Zero axis drift. In the present invention, the flexible hinge can realize large-angle rotational motion and zero shaft drift. Since the direction of rotation of the coil spring of the first coil member is opposite to that of the coil spring of the second coil member, when the transmission member is subjected to a bending moment, when the coil spring of the first coil member converges inward, the coil spring of the second coil member will move toward the inner side. When the coil spring of the first coil expands outward, the coil spring of the second coil converges inward, and the expansion or contraction of the coil spring of the first coil is the same as the contraction of the coil spring of the second coil. When the amount/expansion amount is the same, the generated axial displacements cancel each other, so that the overall structure of the flexible hinge prevents the axis from drifting and can achieve zero drift. Since the helical flexible hinge unit adopts two helical parts with opposite directions of rotation, it can realize large-angle rotation.

Further, in order to reduce the drift of the axis, the first helical member and the second helical member are both formed by screwing an even number of coil springs.

More preferably, both the first helical member and the second helical member are formed by screwing together two or four helical springs.

Further, in order to ensure the realization of zero shaft drift, the size and material of the first screw member and the second screw member are the same.

Further, it includes a plurality of helical flexible hinge units connected in series, all the helical flexible hinge units are arranged coaxially, and the connecting ends of two adjacent helical flexible hinge units share a transmission member. The flexible hinge composed of multiple coaxial lines and serially connected helical flexible hinge units can realize a larger turning angle and achieve zero axis drift at the same time.

Further, in order to facilitate connection and ensure the coaxiality of each component, the intermediate transmission member is of a ring structure.

The beneficial effects of the present invention are: when the flexible hinge of the present invention is subjected to a bending moment, its axis drift is small, even zero axis drift can be realized, and large-angle rotation can be realized, thereby meeting the requirements of flexibility and precision. The invention can realize the large stroke of the flexible hinge, limit the drift of the central axis, meet the requirements of high precision, and can meet the requirements of large stroke and high precision. The invention can be used in the fields of robots and the like, and realizes the rotary motion with larger rotation angle and zero axis drift. In addition, the present invention has simple structure and simple assembly, which reduces the difficulty of production and assembly.

Description of drawings

Fig. 1 is the structural representation of the present invention in the specific embodiment;

Fig. 2 is the structural representation (two-wire system) of the helical member in the present invention in the specific embodiment;

3 is a schematic structural diagram of an intermediate transmission element in the present invention in a specific embodiment;

4 is a schematic diagram of the connection between the intermediate transmission member and the screw member in the present invention in the specific embodiment;

Fig. 5 is the front view of Fig. 4;

Fig. 6 is the top view of Fig. 5;

Fig. 7 is the test result when the helical flexible hinge of the present invention is subjected to positive bending moment in the specific embodiment;

Fig. 8 is the test result when the helical flexible hinge of the present invention is subjected to negative bending moment in the specific embodiment;

Fig. 9 is the center axis drift diagram when the helical flexible hinge of the present invention is subjected to pure bending moment in the specific embodiment;

In the figure, 1, the first transmission member, 2, the intermediate transmission member, 3, the second transmission member, 4, the first screw member, 5, the second screw member.

Detailed ways

The present invention will be further described below through non-limiting examples and in conjunction with the accompanying drawings:

As shown in the drawings, a spiral flexible hinge includes at least one spiral flexible hinge unit, and the spiral flexible hinge unit includes a first transmission member 1, an intermediate transmission member 2, a second transmission member 3, a first spiral 4 and the second helical element 5. The first helical element 4 and the second helical element 5 have the same structure and are formed by at least two helical springs with the same direction of rotation. The first helical element 4 The direction of rotation of the coil spring is opposite to the direction of rotation of the coil spring of the second coil member 5. One end of the first coil member 4 is connected to the first transmission member 1, and the other end of the first coil member 4 is connected to the first transmission member 1. One end is connected with one end of the intermediate transmission member 2, one end of the second screw member 5 is connected with the other end of the intermediate transmission member 2, and the other end of the second screw member 5 is connected with the second transmission member 3 connection, the first transmission member 1, the first screw member 4, the intermediate transmission member 2, the second screw member 5, and the second transmission member 3 are arranged coaxially. In the present invention, both the first helical member 4 and the second helical member 5 can be formed by screwing together two or more coil springs. The first helical member 4 and the second helical member 5 shown in this embodiment are both composed of two The coil spring is screwed together.

In order to reduce the drift of the axis, preferably, the first helical member 4 and the second helical member 5 in the present invention are both formed by screwing an even number of coil springs, for example, there may be 2 or 4 or 6 coils. one and so on. Since the larger the number of coil springs, the larger and more complicated the entire structure will be. Therefore, it is preferable that two or four coil springs are screwed together.

In order to reduce the drift of the axis, it is preferable that the size and material of the first screw 4 and the second screw 5 are the same, so as to ensure that the first screw 4 and the second screw 5 are subjected to a bending moment. The various displacements produced by the two are equal and can cancel each other to ensure the zero axis drift of the flexible hinge.

In order to facilitate connection and to ensure the coaxiality of each component, it is preferable that the intermediate transmission member 2 is a ring structure.

The helical flexible hinge units in the present invention can be connected in series to form a multi-stage serial flexible hinge. When multiple helical flexible hinge units are connected in series, all the helical flexible hinge units are coaxially arranged, and two adjacent helical The connecting ends of the flexible hinge units share a transmission member. Using a flexible hinge in which multiple helical flexible hinge units are connected in series, the rotation angle of the hinge is greatly increased, and zero axis drift is achieved at the same time.

For the helical flexible hinge of the present invention, the rotation angle test and the shaft drift test are carried out. The test method and data are obtained by simulation using the finite element method. The material of the flexible hinge used in the test is aluminum alloy, and its yield limit is 505MPa.

As shown in Figures 7-8, one end of the flexible hinge is used as the fixed end, and a gradually increasing torque is applied to the other end to obtain the rotation range of the flexible hinge. Figure 7 shows the flexible hinge when it is subjected to a positive bending moment. Figure 8 shows the test results when the flexible hinge is subjected to a negative bending moment. According to the test, when the rotation angle reaches ±150 degrees, the maximum stress of the flexible hinge is 447MPa, and no plastic deformation will occur, that is, the flexible hinge can realize a rotation of plus or minus 150 degrees, and its rotation angle is much larger than that of the flexible hinge in the prior art. 40°-50° turning angle range.

Apply pure bending moment M to the flexible hinge, the value range is -44-44N.mm. The flexible hinge rotates, and its central axis drift changes with the change of M. According to the simulation results of the finite element model, the simulation data of the central axis drift under pure bending moment M is shown in Figure 9. From Figure 9, it can be seen that the The flexible hinge realizes the limit of the overall central axis drift, and the maximum is only 0.023mm.

It can be seen that the helical flexible hinge of the present invention can realize large-angle rotation, and the shaft drift is small, which can meet the requirements of high precision, and can meet the requirements of large stroke and high precision. The invention can be used in the fields of robots and the like, and realizes the rotary motion with larger rotation angle and zero axis drift.

Other parts in this embodiment are in the prior art, and will not be repeated here.

Claims (4)

1. A spiral flexible hinge is characterized in that: the flexible hinge comprises at least one flexible spiral hinge unit, wherein the flexible spiral hinge unit comprises a first transmission piece (1), an intermediate transmission piece (2), a second transmission piece (3), a first spiral piece (4) and a second spiral piece (5), the first spiral piece (4) and the second spiral piece (5) are identical in structure and are formed by screwing at least two spiral springs with the same screwing direction, the screwing direction of the spiral spring of the first spiral piece (4) is opposite to that of the spiral spring of the second spiral piece (5), one end of the first spiral piece (4) is connected with the first transmission piece (1), the other end of the first spiral piece (4) is connected with one end of the intermediate transmission piece (2), one end of the second spiral piece (5) is connected with the other end of the intermediate transmission piece (2), the other end of the second spiral piece (5) is connected with the second transmission piece (3), and the first transmission piece (1), the first spiral piece (4), the intermediate transmission piece (2), the second spiral piece (5) and the second transmission piece (3) are arranged coaxially; the first spiral piece (4) and the second spiral piece (5) are formed by screwing two or four spiral springs, and the rotation starting points of every two spiral springs in each spiral piece are symmetrically arranged.

2. The spiral flexible hinge of claim 1, further comprising: the first spiral piece (4) and the second spiral piece (5) are the same in size and material.

3. The spiral flexible hinge according to claim 1 or 2, characterized in that: including a plurality of spiral flexible hinge units of establishing ties mutually, all spiral flexible hinge units all coaxial line sets up to a driving medium is shared to two adjacent spiral flexible hinge unit's link.

4. The spiral flexible hinge according to claim 3, characterized in that: the intermediate transmission member (2) is of a circular ring structure.

Images