Integrated joint module brake structure based on memory alloy driving

Abstract

The application belongs to the technical field of robots, and provides an integrated joint module brake structure based on memory alloy driving, in order to solve the problems of large volume, high energy consumption and easy to slip of electromagnetic and hydraulic brake structures. The brake structure of the frameless torque motor is constituted by the tight brake memory alloy wire, the loose brake memory alloy wire and the wedge block telescopic structure, is directly installed on the rotating disc side of the motor rotor of the frameless torque motor through the base, the left and right direction movement of the lower wedge block is controlled through the tight brake memory alloy wire and the loose brake memory alloy wire, and then the upper wedge block is driven to contact or separate from the rotating disc, so that the brake function of the rotating disc is realized. The application has the advantages of compact structure, small space occupation and low energy consumption.

Description

Technical Field

[0001] This invention belongs to the field of robotics technology, specifically relating to an integrated joint module brake structure based on shape memory alloy drive, which is particularly suitable for frameless torque motors. Background Technology

[0002] Most existing robot joint modules use electromagnetic or hydraulic braking structures for braking, which have problems such as large size and high requirements for installation cavity. They cannot meet the design requirements of "high power density and compactness" of frameless torque motors. If additional installation space is reserved, the overall size of the joint module will increase, which will limit the lightweight and miniaturized application of robot joints.

[0003] Meanwhile, joints using electromagnetic braking structures require power to operate and rotate normally, resulting in high energy consumption. Furthermore, electromagnetic and hydraulic braking structures often use metal materials with rigid contact between the metal material and the output end (output disc), leading to poor anti-slip performance and a tendency to slip during braking. Summary of the Invention

[0004] In order to at least partially solve the above-mentioned technical problems, the present invention provides an integrated joint module braking structure based on shape memory alloy drive, which has the advantages of compact structure and small space occupation, and is particularly suitable for braking frameless torque motors to meet the requirements of lightweight and miniaturized robot joint design; at the same time, it solves the problems of high energy consumption and easy slippage of electromagnetic and hydraulic braking structures.

[0005] To solve the technical problem, the technical solution adopted by this invention is as follows: An integrated joint module braking structure based on shape memory alloy actuation, comprising: A base for mounting on the turntable side of the motor rotor of a frameless torque motor; The wedge block telescopic structure includes a wedge block fixing bracket mounted on a base. A lower wedge block and an upper wedge block for contacting the turntable of the motor rotor are mounted on the wedge block fixing bracket. The contact surface between the upper wedge block and the lower wedge block is an inclined surface. When the lower wedge block moves left and right, it can drive the upper wedge block to telescopically extend and retract along the wedge block fixing bracket. A tight-fitting shape memory alloy wire is connected to one end of the lower wedge block to drive the lower wedge block to move in one direction (e.g., the lower wedge block moves to the left), which in turn drives the upper wedge block to extend out of the wedge block fixing bracket and contact the turntable for braking; The loosening shape memory alloy wire is connected to the other end of the lower wedge block and is used to drive the lower wedge block to move in another direction (for example, the lower wedge block moves to the right), thereby driving the upper wedge block to retract into the wedge block fixing bracket and disengage from the turntable.

[0006] In some embodiments, the upper wedge is made of rubber, or at least the tip of the upper wedge that contacts the turntable is made of rubber.

[0007] In some embodiments, both the brake tightening memory alloy wire and the brake loosening memory alloy wire are electrically shrinkable memory alloy wires.

[0008] In some embodiments, the tangent of the slope helix angle of the inclined contact surfaces of the upper and lower wedge blocks is less than the coefficient of friction between the upper and lower wedge blocks.

[0009] In some embodiments, the upper wedge block is equipped with a preload spring for keeping the upper wedge block in contact with the lower wedge block. The upper end of the preload spring is connected to the upper wedge block, and the lower end of the preload spring is fixed to the base or to the wedge block fixing bracket.

[0010] In some embodiments, the upper wedge block has an installation cavity, a slide rod is installed in the installation cavity, the upper end of the preload spring is hung on the slide rod, and the lower wedge block has a strip-shaped through hole for the preload spring to pass through.

[0011] In some embodiments, a microswitch is installed on the side of the base near the brake release memory alloy wire for contacting the lower wedge block. The microswitch is used to detect the brake release stroke of the lower wedge block and control the brake release memory alloy wire to be de-energized.

[0012] In the specific implementation process, a first insulating ring for winding a tight brake memory alloy wire is installed on the base. One end of the tight brake memory alloy wire is fixed to the first connection point, and the other end of the tight brake memory alloy wire passes around the pin on the lower wedge block and is wound around the first insulating ring before being fixed to the second connection point. A second insulating ring for winding a loose brake memory alloy wire is installed on the base. A third connection point is provided below the micro switch. One end of the loose brake memory alloy wire is fixed to the third connection point, and the other end of the loose brake memory alloy wire passes around the pin on the lower wedge block and is wound around the second insulating ring before being fixed to the second connection point.

[0013] Compared with the prior art, the present invention has the following beneficial effects: This invention utilizes a tight-brake memory alloy wire, a loose-brake memory alloy wire, and a wedge-shaped block telescopic structure to form a braking structure for a frameless torque motor. It is directly mounted on the turntable side of the motor rotor via a base. The tight-brake and loose-brake memory alloy wires control the left-right movement of the lower wedge block, thereby causing the upper wedge block to contact or disengage from the turntable, achieving the braking function of the turntable. This invention eliminates the complex structures of electromagnetic and hydraulic braking systems. It has the advantages of compact structure, small footprint, and convenient installation. It meets the compact design requirements of frameless torque motors, thus satisfying the design applications of lightweight and miniaturized robot joints.

[0014] The upper wedge block of the present invention is made of rubber, or at least the top end of the upper wedge block is made of rubber; so that the upper wedge block and the turntable of the motor rotor have a flexible contact, thereby improving the braking ability of the turntable and avoiding the problem of slippage during braking.

[0015] In this invention, the tangent of the slope angle of the inclined contact surfaces of the upper and lower wedge blocks is less than the coefficient of friction between the upper and lower wedge blocks, thereby achieving self-locking after braking. Even after the power to the brake memory alloy wire is cut off, the braking effect can be maintained by the self-locking between the upper and lower wedge blocks. During braking and releasing, only a short period of power is needed for both the brake memory alloy wire and the release memory alloy wire, which can greatly reduce energy consumption. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a structure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of another structural aspect of an embodiment of the present invention; Figure 3 This is a schematic diagram of an embodiment of the wedge-shaped block telescopic structure of the present invention; Figure 4 This is a schematic diagram of the wedge-shaped block telescopic structure of the present invention from another angle, through comparison with... Figure 3 The comparison shows that the contact surface between the upper and lower wedge blocks is an inclined surface; Figure 5 This is a schematic diagram of the wedge block telescopic structure of the present invention after removing part of the wedge block fixing bracket. It can be clearly seen that the contact surface between the upper wedge block and the lower wedge block is an inclined surface. Figure 6 This is a schematic diagram of the wedge block telescopic structure of the present invention after removing part of the wedge block fixing bracket and the upper wedge block, which shows the installation method of the preload spring; Figure 7 This is a schematic diagram of the assembly of the upper wedge block and the preload spring; Figure 8This is a schematic diagram of the brake structure of the present invention installed on a frameless torque motor.

[0017] Reference numerals: 1. Base; 2. Wedge block telescopic structure; 21. Wedge block fixing bracket; 22. Upper wedge block; 221. Slide rod; 23. Lower wedge block; 231. Pin shaft; 232. Strip-shaped through hole; 24. Preload spring; 3. Braking memory alloy wire; 4. Releasing memory alloy wire; 5. Micro switch; 6. First insulating ring; 7. First connection point; 8. Second connection point; 9. Second insulating ring; 01. Motor rotor; 02. Turntable. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are some, but not all, of the embodiments of the present invention. The following embodiments are only for specific illustration of the implementation methods of the present invention and do not limit the scope of protection of the present invention.

[0019] Combined with appendix Figure 1 To be continued Figure 8 The present invention provides an integrated joint module braking structure based on shape memory alloy drive, comprising: Base 1, for mounting on the turntable 02 side of the motor rotor 01 of the frameless torque motor; The wedge block telescopic structure 2 includes a wedge block fixing bracket 21 mounted on a base 1. A lower wedge block 23 and an upper wedge block 22 for contacting the turntable 02 of the motor rotor are mounted on the wedge block fixing bracket 21. The contact surface between the upper wedge block 22 and the lower wedge block 23 is an inclined surface. When the lower wedge block 23 moves left and right, it can drive the upper wedge block 22 to extend and retract along the wedge block fixing bracket 21. The tight-fitting memory alloy wire 3 is connected to one end (e.g., the left end) of the lower wedge block 23, which is used to drive the lower wedge block 23 to move in one direction (e.g., the lower wedge block moves to the left), thereby driving the upper wedge block 22 to extend out of the wedge block fixing bracket 21 and contact the turntable 02 for braking; The loose brake memory alloy wire 4 is connected to the other end (e.g., the right end) of the lower wedge block 23, and is used to drive the lower wedge block 23 to move in the opposite direction (e.g., the lower wedge block moves to the right), thereby driving the upper wedge block 22 to retract into the wedge block fixing bracket 21 and disengage from the turntable 02.

[0020] Combined with appendix Figure 5 In the specific implementation process, pins 231 are installed on both the left and right sides of the lower end of the lower wedge block 23 for the tight brake memory alloy wire 3 and the loose brake memory alloy wire 4 to pass through.

[0021] Combined with appendix Figure 3Appendix Figure 4 Appendix Figure 6 and attached Figure 7 In order to increase the contact area between the upper wedge block 22 and the lower wedge block 23, the top of the lower wedge block 23 has an inclined protrusion, and the lower end of the upper wedge block 22 has an inclined groove. The contact area between the lower wedge block 23 and the upper wedge block 22 is increased by the cooperation of the protrusion and the groove.

[0022] As some alternatives to the present invention, the longitudinal cross-section of the protrusion and the groove is triangular, isosceles trapezoidal, or dovetail-shaped. Among them, the dovetail-shaped protrusion and groove can also limit wobbling and ensure close contact between the upper wedge block and the lower wedge block.

[0023] This invention utilizes a tight-brake memory alloy wire, a loose-brake memory alloy wire, and a wedge-shaped block telescopic structure to form a braking structure for a frameless torque motor. It is directly mounted on the turntable side of the motor rotor via a base. The tight-brake and loose-brake memory alloy wires control the left-right movement of the lower wedge block, thereby causing the upper wedge block to contact or disengage from the turntable, achieving the braking function of the turntable. This invention eliminates the complex structures of electromagnetic and hydraulic braking systems. It has the advantages of compact structure, small footprint, and convenient installation. It meets the compact design requirements of frameless torque motors, thus satisfying the design applications of lightweight and miniaturized robot joints.

[0024] Electromagnetic brake structures typically include core components such as coils, springs, and iron cores. They not only occupy a lot of space but also have a complicated installation process. Furthermore, the electromagnetic brake structure requires power during operation to ensure the normal rotation of the joint, resulting in high energy consumption.

[0025] Hydraulic brakes typically include core components such as brake calipers, brake discs, hydraulic pumps, and pipelines, which also present problems such as large space requirements and complicated assembly and maintenance.

[0026] In some embodiments, the upper wedge block 22 is made of rubber, or at least the tip of the upper wedge block 22 that contacts the turntable is made of rubber (i.e., at least the tip of the upper wedge block that contacts the turntable is made of rubber). This makes the contact between the upper wedge block 22 and the turntable 02 of the motor rotor 01 a flexible contact, thereby improving the braking capability of the turntable 02 and avoiding slippage during braking. In contrast, existing electromagnetic and hydraulic brakes have rigid contact with the motor output end (such as the output disc or output flange), which is prone to slippage during braking.

[0027] In some embodiments, both the braking shape memory alloy wire 3 and the releasing shape memory alloy wire 4 are electrically conductive shrinkable shape memory alloy wires. This invention allows for short-term energization of the braking shape memory alloy wire 3 and the releasing shape memory alloy wire 4 during braking or releasing. Compared to existing electromagnetic and hydraulic braking structures, this has the advantage of low energy consumption.

[0028] In the specific implementation process, the tight brake memory alloy wire 3 and the loose brake memory alloy wire 4 are made of NiTi shape memory alloy. When the NiTi shape memory alloy is energized, it contracts and drives the lower wedge block to move left and right. When the NiTi shape memory alloy is de-energized, it automatically returns to its original length.

[0029] In some embodiments, the tangent of the slope angle of the inclined contact surfaces of the upper wedge block 22 and the lower wedge block 23 is less than the friction coefficient of the upper wedge block 22 and the lower wedge block 23, thereby achieving self-locking after braking.

[0030] Combined with appendix Figure 6 and attached Figure 7 In some embodiments, the upper wedge block 22 is equipped with a preload spring 24 for maintaining contact between the upper wedge block 22 and the lower wedge block 23. The upper end of the preload spring 24 is connected to the upper wedge block 22, and the lower end of the preload spring 24 is fixed to the base 1 or to the wedge block fixing bracket 21. The preload spring 24 ensures close contact between the upper wedge block 22 and the lower wedge block 23, preventing wobbling between them during movement and facilitating precise control of the extension and retraction of the upper wedge block.

[0031] Combined with appendix Figure 6 and attached Figure 7 In some embodiments, the upper wedge block 22 has a mounting cavity, in which a slide rod 221 is installed. The upper end of the preload spring 24 is hung on the slide rod 221, and the lower wedge block 23 has a strip-shaped through hole 232 for the preload spring 24 to pass through. The strip-shaped through hole 232 also provides space for the preload spring 24 to move. Since the upper wedge block can only move vertically along the wedge block fixing bracket (i.e., extend outwards or retract inwards), while the lower wedge block needs to move left and right, the strip-shaped through hole provides space for the spring to move when the lower wedge block moves left and right, preventing the preload spring from touching the lower wedge block and hindering its movement.

[0032] Combined with appendix Figure 1 and attached Figure 2In some embodiments, a microswitch 5 is installed on the base 1 near the brake release memory alloy wire 4 for contacting the lower wedge block 23. The microswitch 5 is used to detect the brake release stroke of the lower wedge block 23 and control the brake release memory alloy wire 4 to be de-energized. The microswitch 5 is a limit switch; when the lower wedge block 23 moves a certain distance toward the microswitch 5, the lower wedge block 23 touches the microswitch 5, controlling the brake release memory alloy wire 4 to be de-energized. The principle of the limit switch is clear and understandable to those skilled in the art and will not be elaborated further here.

[0033] During braking, the braking structure of this invention operates as follows: a preset current is applied to the braking memory alloy wire, causing it to contract and pull the lower wedge block to move to the left; the lower wedge block, through the action of the inclined plane, pushes the upper wedge block to extend along the wedge block fixing bracket and make close contact with the turntable surface of the motor rotor; the rubber material of the upper wedge block undergoes elastic deformation, storing clamping force, and at the same time, because the tan value of the inclined plane is less than the coefficient of friction, the two wedge blocks form a self-locking mechanism, maintaining the braking state even if the braking memory alloy wire is de-energized.

[0034] When the brake structure of the present invention is released (i.e., when the brake needs to be released): a preset current is passed through the release brake memory alloy wire, the release brake memory alloy wire is energized and contracts, pulling the lower wedge block to move to the right; the upper wedge block retracts under the restoring force of the pre-tensioned spring and disengages from the motor rotor disc; when the lower wedge block moves to the right to a preset distance, the micro switch on the right side is triggered, the micro switch outputs a signal to cut off the power supply to the release brake memory alloy wire, the memory alloy wire stops contracting, the lower wedge block stops moving, and the release brake is completed.

[0035] Combined with appendix Figure 1 and attached Figure 2 In the specific implementation process, a first insulating ring 6 for winding the tight brake memory alloy wire 3 is installed on the base 1. One end of the tight brake memory alloy wire 3 is fixed on the first connection point 7, and the other end of the tight brake memory alloy wire 3 passes around the pin 231 on the lower wedge block 23 and is wound around the first insulating ring 6 before being fixed on the second connection point 8. A second insulating ring 9 for winding the loose brake memory alloy wire 4 is installed on the base 1. A third connection point is provided below the micro switch 5. One end of the loose brake memory alloy wire 4 is fixed on the third connection point, and the other end of the loose brake memory alloy wire 4 passes around the pin 231 on the lower wedge block 23 and is wound around the second insulating ring 9 before being fixed on the second connection point 8.

[0036] In the specific implementation process, pins 231 are provided at both ends of the lower wedge block 23, and the tight brake memory alloy wire 3 and the loose brake memory alloy wire 4 pass around the pins 231 at both ends of the lower wedge block 23.

[0037] Specifically, when current is applied to the first connection point 7 and the second connection point 8, the tight brake memory alloy wire 3 is energized and retracts; when current is applied to the second connection point 8 and the third connection point, the loose brake memory alloy wire 4 is energized and retracts.

[0038] The first insulating ring 6 is used to wind more tight brake memory alloy wires 3, and the second insulating ring 9 is used to wind more loose brake memory alloy wires 4, so as to meet the requirements for the lower wedge block 23 to slide left and right, thereby controlling the upper wedge block 22 to extend out of the wedge block fixing bracket 21 and brake the turntable 02.

[0039] As a preferred embodiment of the present invention, in order to facilitate the sliding of the tight brake memory alloy wire 3 and the loose brake memory alloy wire 4 during contraction and extension, the surfaces of the first insulating ring 6, the second insulating ring 9 and the pin 231 are smoothed to reduce the friction with the memory alloy wire.

[0040] It should be understood that the above description of the preferred embodiments is quite detailed, but it should not be considered as a limitation on the scope of protection of this invention. Those skilled in the art, under the guidance of this invention, can make substitutions or modifications without departing from the scope of protection of the claims of this invention, and all such substitutions or modifications fall within the scope of protection of this invention. The scope of protection of this invention should be determined by the appended claims.

Claims

1. A brake structure for an integrated joint module driven by shape memory alloy, characterized in that, include: The base (1) is used to be installed on the turntable (02) side of the motor rotor (01) of the frameless torque motor; The wedge block telescopic structure (2) includes a wedge block fixing bracket (21) mounted on a base (1). A lower wedge block (23) and an upper wedge block (22) for contacting the turntable (02) of the motor rotor are mounted on the wedge block fixing bracket (21). The contact surface between the upper wedge block (22) and the lower wedge block (23) is an inclined surface. When the lower wedge block (23) moves left and right, it can drive the upper wedge block (22) to telescopically extend and retract along the wedge block fixing bracket (21). The tight-braking memory alloy wire (3) is connected to one end of the lower wedge block (23) to drive the lower wedge block to move in one direction, thereby driving the upper wedge block (22) to extend out of the wedge block fixing bracket (21) and contact the turntable (02) for braking; The loose brake memory alloy wire (4) is connected to the other end of the lower wedge block (23) to drive the lower wedge block (23) to move in another direction, thereby driving the upper wedge block (22) to retract into the wedge block fixing bracket (21) and disengage from the turntable (02).

2. The integrated joint module brake structure based on shape memory alloy drive according to claim 1, characterized in that, The upper wedge (22) is made of rubber, or at least the top of the upper wedge (22) that contacts the turntable (02) is made of rubber.

3. The integrated joint module brake structure based on shape memory alloy drive according to claim 1, characterized in that, Both the tight brake memory alloy wire (3) and the loose brake memory alloy wire (4) are electrically shrinkable memory alloy wires.

4. The integrated joint module brake structure based on shape memory alloy drive according to claim 1, characterized in that, The tangent of the slope angle of the inclined contact surface of the upper wedge (22) and the lower wedge (23) is less than the friction coefficient of the upper wedge (22) and the lower wedge (23).

5. The integrated joint module brake structure based on shape memory alloy drive according to any one of claims 1-4, characterized in that, The upper wedge block (22) is equipped with a preload spring (24) for keeping the upper wedge block in contact with the lower wedge block. The upper end of the preload spring (24) is connected to the upper wedge block (22), and the lower end of the preload spring (24) is fixed to the base (1) or fixed to the wedge block fixing bracket.

6. The integrated joint module brake structure based on shape memory alloy drive according to claim 5, characterized in that, The upper wedge block (22) has an installation cavity, and a slide rod (221) is installed in the installation cavity. The upper end of the preload spring (24) is hung on the slide rod (221). The lower wedge block (23) has a strip-shaped through hole (232) for the preload spring (24) to pass through.

7. The integrated joint module brake structure based on shape memory alloy drive according to claim 1, characterized in that, A micro switch (5) for contacting the lower wedge block (23) is installed on the side of the base (1) near the brake release memory alloy wire (4). The micro switch (5) is used to detect the brake release stroke of the lower wedge block (23) and control the brake release memory alloy wire (4) to be de-energized.

8. The integrated joint module brake structure based on shape memory alloy drive according to claim 7, characterized in that, The base (1) is equipped with a first insulating ring (6) for winding the tight brake memory alloy wire (3). One end of the tight brake memory alloy wire (3) is fixed on the first connection point (7). The other end of the tight brake memory alloy wire (3) passes around the pin (231) on the lower wedge block (23) and is wound around the first insulating ring (6) before being fixed on the second connection point (8). The base (1) is equipped with a second insulating ring (9) for winding the loose brake memory alloy wire (4). A third connection point is provided below the micro switch (5). One end of the loose brake memory alloy wire (4) is fixed on the third connection point. The other end of the loose brake memory alloy wire (4) passes around the pin (231) on the lower wedge block (23) and is wound around the second insulating ring (9) before being fixed on the second connection point (8).

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