Double-rigid-wheel harmonic speed reducer with torque sensing function

Abstract

The utility model provides a double-rigid-gear harmonic speed reducer with a torque sensing function, which relates to the technical field of speed reducers and comprises a wave generator, a flexible bearing, a flexible gear, an output end rigid gear, a crossed roller bearing and a fixed end rigid gear. The crossed roller is arranged between the bearing outer ring and the output end rigid wheel, the output end rigid wheel serves as an inner ring of the crossed roller bearing, and the fixed end rigid wheel is detachably and fixedly connected with the bearing outer ring; the two end faces of the fixed end rigid wheel are each provided with a receding groove coaxial with the fixed end rigid wheel, a connecting wall is formed between the bottoms of the two receding grooves, and a plurality of strain gauges arranged in a circumferential array mode are installed at the position, close to one side of the output end rigid wheel, of the bottom of the receding groove. The elastic strain gauge is embedded in the rigid fixed end rigid wheel, so that the fixed end rigid wheel has a torque sensing function, the axial thickness of the harmonic speed reducer is not increased, and the use requirements of more occasions are met.

Description

Technical Field

[0001] This utility model relates to the field of speed reduction device technology, and in particular to a dual rigid wheel harmonic speed reducer with torque sensing. Background Technology

[0002] When harmonic reducers are used in robot joints, torque sensors are usually required to detect their torque. As an elastic component, the torque sensor is typically mounted on the rigid wheel using screws or similar methods in the current technology. This undoubtedly increases the axial thickness of the harmonic reducer. In practical applications, especially when the harmonic reducer is used in extremely confined spaces, the impact of increased axial thickness is significant. Utility Model Content

[0003] The purpose of this invention is to provide a dual rigid wheel harmonic reducer with torque sensing. By embedding elastic strain gauges in the rigid fixed end rigid wheel, the fixed end rigid wheel can simultaneously have torque sensing function without increasing the axial thickness of the harmonic reducer, thus meeting the application requirements of more occasions.

[0004] The above-mentioned technical objective of this utility model is achieved through the following technical solution:

[0005] A dual-rigid-wheel harmonic reducer with torque sensing includes a wave generator, flexible bearings, a flexible wheel, an output-end rigid wheel, a cross-roll bearing, and a fixed-end rigid wheel. The flexible bearings are arranged between the wave generator and the flexible wheel, and two are arranged side by side along the axial direction of the wave generator. The external teeth of the flexible wheel mesh with the internal teeth of the output-end rigid wheel and the internal teeth of the fixed-end rigid wheel, respectively. The two flexible bearings correspond to the internal teeth of the output-end rigid wheel and the internal teeth of the fixed-end rigid wheel, respectively.

[0006] The cross roller bearing includes cross rollers and an outer ring. The cross rollers are disposed between the outer ring and the output end rigid wheel. The output end rigid wheel serves as the inner ring of the cross roller bearing, and the fixed end rigid wheel and the outer ring are detachably and fixedly connected.

[0007] The fixed end rigid wheel has a relief groove on each of its two end faces, which is coaxial with the fixed end rigid wheel. A connecting wall is formed between the bottom of the two relief grooves. Several strain gauges arranged in a circular array are installed on the bottom of the relief groove near the output end rigid wheel.

[0008] By adopting the above technical solution, clearance grooves are opened on both ends of the fixed-end rigid wheel, forming a connecting wall between the two clearance grooves. An elastic strain gauge is embedded in the clearance groove closest to the output-end rigid wheel. This allows a strain gauge with torque sensing function to be embedded on the output-end rigid wheel, and the connecting wall ensures that the strain gauge can normally detect the magnitude of the applied torque. The fixed-end rigid wheel thus possesses torque sensing functionality, while the elastic strain gauge does not increase the axial thickness of the harmonic reducer. Compared to integrating an elastic torque sensor onto a flexible wheel, this invention integrates an elastic strain gauge onto a rigid torque sensor, reducing the influence of bending moments in other directions on the torsional torque detected by the strain gauge.

[0009] The fixed end rigid wheel and the outer ring of the bearing are integrated.

[0010] By adopting the above technical solution, the fixed end rigid wheel and the bearing outer ring are integrated, and the strain gauge is integrated on the fixed end rigid wheel. This is equivalent to the fixed end rigid wheel, the bearing outer ring, and the torque sensor being integrated into one unit. The bearing outer ring can compensate for the part of the rigidity lost by the fixed end rigid wheel for embedding the strain gauge, further improving its performance. At the same time, it can also shorten the axial length of the fixed end rigid wheel to a certain extent. Furthermore, there is no need for positioning and installation between the bearing outer ring and the fixed end rigid wheel, effectively reducing accuracy errors.

[0011] A four-point contact ball bearing is installed in the clearance groove away from the output end rigid wheel.

[0012] By adopting the above technical solution, a four-point contact ball bearing is installed in the relief groove far from the output end rigid wheel. While not affecting the deformation in the torque direction, the four-point contact ball bearing avoids the influence of bending moment on the strain gauge, thereby improving the accuracy of torque testing.

[0013] The axial thickness of the connecting wall along the fixed end rigid wheel is 20%-70% of the length of the internal teeth of the fixed end rigid wheel.

[0014] By adopting the above technical solution, the axial thickness of the connecting wall is matched with the length of the inner teeth of the fixed end rigid wheel. While ensuring the meshing effect between the fixed end rigid wheel and the flexible wheel, it avoids the normal operation of the strain gauge due to excessive axial thickness of the connecting wall, and also avoids excessive rigidity loss of the fixed end rigid wheel due to excessive axial thickness of the connecting wall.

[0015] The radial length of the connecting wall along the fixed end rigid wheel is 20%-70% of the radial thickness of the fixed end rigid wheel.

[0016] By adopting the above technical solution, the radial length of the connecting wall and the radial thickness of the fixed end rigid wheel are matched, which avoids the excessive axial thickness of the connecting wall affecting the normal operation of the strain gauge, while also avoiding the excessive rigidity loss of the fixed end rigid wheel due to the excessive axial thickness of the connecting wall.

[0017] The wall thickness between the side wall of the relief groove near the inner tooth of the fixed end rigid wheel and the inner hole of the fixed end rigid wheel is not less than twice the tooth height of the inner tooth of the fixed end rigid wheel.

[0018] By adopting the above technical solution, the wall thickness between the side wall of the groove near the inner tooth of the fixed end rigid wheel and the inner hole of the fixed end rigid wheel is not less than twice the tooth height of the inner tooth of the fixed end rigid wheel. This avoids the wall thickness at the position where the inner tooth of the fixed end rigid wheel is machined being too thin, which would affect the normal machining of the inner tooth, and also avoids excessive rigidity loss of the fixed end rigid wheel.

[0019] In summary, this utility model has the following beneficial effects:

[0020] 1. This utility model provides a torque sensing function to the fixed end rigid wheel by opening relief grooves on both ends of the fixed end rigid wheel, forming a connecting wall between the two relief grooves, and embedding elastic strain gauges in the relief grooves near the output end rigid wheel, while the elastic strain gauges do not increase the axial thickness of the harmonic reducer.

[0021] 2. In this utility model, the fixed end rigid wheel and the bearing outer ring are integrated, which is equivalent to the fixed end rigid wheel, the bearing outer ring, and the torque sensor being integrated. The bearing outer ring can compensate for the rigidity loss of the fixed end rigid wheel due to the installation of strain gauges, further improving its performance. At the same time, it can also shorten the axial length of the fixed end rigid wheel to a certain extent. Furthermore, there is no need for positioning and installation between the bearing outer ring and the fixed end rigid wheel, effectively reducing accuracy errors.

[0022] 3. This utility model improves the accuracy of torque testing by installing a four-point contact ball bearing in the relief groove away from the output end rigid wheel, without affecting the deformation in the torque direction, and avoiding the influence of bending moment on the strain gauge. Attached Figure Description

[0023] Figure 1 It is a dual rigid wheel harmonic reducer with torque sensing as described in Embodiment 1;

[0024] Figure 2 It is a dual rigid wheel harmonic reducer with torque sensing in Embodiment 2;

[0025] Figure 3 It is a dual rigid wheel harmonic reducer with torque sensing in Embodiment 3;

[0026] Figure 4 It is a dual rigid wheel harmonic reducer with torque sensing in Embodiment 4.

[0027] In the figure, 1 is the wave generator; 2 is the flexible bearing; 3 is the flexure; 4 is the output end rigid wheel; 5 is the cross roller bearing; 51 is the cross roller; 52 is the outer ring of the bearing; 6 is the fixed end rigid wheel; 61 is the relief groove; 62 is the connecting wall; 7 is the strain gauge; and 8 is the four-point contact ball bearing. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0029] Example 1:

[0030] A dual rigid wheel harmonic reducer with torque sensing, such as Figure 1 As shown, its basic structure and working principle are the same as those in the prior art. It includes a wave generator 1, a flexible bearing 2, a flexible wheel 3, an output end rigid wheel 4, a cross-rolled bearing 5, and a fixed end rigid wheel 6 arranged coaxially. The flexible bearing 2 is arranged between the wave generator 1 and the flexible wheel 3 and two are arranged side by side along the axial direction of the wave generator 1. The external teeth of the flexible wheel 3 mesh with the internal teeth of the output end rigid wheel 4 and the internal teeth of the fixed end rigid wheel 6 respectively, and one meshes with a different number of teeth and the other meshes with the same number of teeth. The two flexible bearings 2 correspond to the internal teeth of the output end rigid wheel 4 and the internal teeth of the fixed end rigid wheel 6 respectively.

[0031] like Figure 1 As shown, the cross roller bearing 5 includes cross rollers 51 and bearing outer ring 52. The cross rollers 51 are disposed between the bearing outer ring 52 and the output end rigid wheel 4. The output end rigid wheel 4 serves as the inner ring of the cross roller bearing 5, and the fixed end rigid wheel 6 and the bearing outer ring 52 are detachably fixedly connected by screws.

[0032] like Figure 1 As shown, in this embodiment, relief grooves 61, coaxial with the fixed-end rigid wheel 6, are respectively provided on the two end faces of the fixed-end rigid wheel 6. A connecting wall 62 is formed between the bottoms of the two relief grooves 61. Several strain gauges 7 arranged in a circular array are installed on the bottom of the relief groove 61 near the output-end rigid wheel 4. In this way, the strain gauges 7 with torque sensing function are embedded in the output-end rigid wheel 4, and the setting of the connecting wall 62 ensures that the strain gauges 7 can normally detect the magnitude of the torque. The fixed-end rigid wheel 6 has torque sensing function, and the elastic strain gauges 7 do not increase the axial thickness of the harmonic reducer. Compared with integrating the elastic torque sensor on the flexible wheel 3, this utility model integrates the elastic strain gauges 7 on the rigid torque sensor, which can reduce the influence of bending moments in other directions on the torsional torque detected by the strain gauges 7.

[0033] like Figure 1As shown, in this embodiment, the axial thickness of the connecting wall 62 along the fixed end rigid wheel 6 is 20%-70% of the length of the internal teeth of the fixed end rigid wheel 6, and the radial length of the connecting wall 62 along the fixed end rigid wheel 6 is 20%-70% of the radial thickness of the fixed end rigid wheel 6. The wall thickness between the side wall of the relief groove 61 near the internal teeth of the fixed end rigid wheel 6 and the inner hole of the fixed end rigid wheel 6 is not less than twice the tooth height of the internal teeth of the fixed end rigid wheel 6. This optimization of the axial thickness and radial thickness of the connecting wall 62, as well as the wall thickness between the side wall of the relief groove 61 near the internal teeth of the fixed end rigid wheel 6 and the inner hole of the fixed end rigid wheel 6, ensures the meshing effect between the fixed end rigid wheel 6 and the flexible wheel 3, avoids excessive axial thickness of the connecting wall 62 affecting the normal operation of the strain gauge 7, and also avoids excessive rigidity loss of the fixed end rigid wheel 6 due to excessively thin axial thickness of the connecting wall 62. At the same time, it avoids excessively thin wall thickness at the machining position of the internal teeth of the fixed end rigid wheel 6, which would affect the normal machining of the internal teeth.

[0034] Example 2:

[0035] A dual rigid wheel harmonic reducer with torque sensing, such as Figure 1 and Figure 2 As shown, the difference from Embodiment 1 is that the fixed end rigid wheel 6 and the bearing outer ring 52 are integrated. This integration of the fixed end rigid wheel 6 and the bearing outer ring 52 is equivalent to integrating the fixed end rigid wheel 6, the bearing outer ring 52, and the torque sensor. The bearing outer ring 52 can compensate for the rigidity loss of the fixed end rigid wheel 6 due to the installation of the strain gauge 7, further improving its performance. At the same time, it can also shorten the axial length of the fixed end rigid wheel 6 to a certain extent. Furthermore, there is no need for positioning and installation between the bearing outer ring 52 and the fixed end rigid wheel 6, effectively reducing accuracy errors.

[0036] Example 3:

[0037] A dual rigid wheel harmonic reducer with torque sensing, such as Figure 1 and Figure 3 As shown, the difference from Embodiment 1 is that a four-point contact ball bearing 8 is installed in the relief groove 61 away from the output end rigid wheel 4. In this way, without affecting the deformation in the torque direction, the four-point contact ball bearing 8 avoids the influence of bending moment on the strain gauge 7, thereby improving the accuracy of torque testing.

[0038] Example 4:

[0039] A dual rigid wheel harmonic reducer with torque sensing, such as Figure 2 and Figure 4As shown, the difference from Embodiment 2 is that a four-point contact ball bearing 8 is installed in the relief groove 61, which is far from the output end rigid wheel 4. In addition to using the outer ring 52 of the bearing to compensate for part of the rigidity lost by the fixed end rigid wheel 6, the four-point contact ball bearing 8 also avoids the influence of bending moment on the strain gauge 7 without affecting the deformation in the torque direction, thereby improving the accuracy of torque testing.

[0040] The foregoing description illustrates and describes preferred embodiments of the present invention. As previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or related technical or knowledge. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A dual rigid wheel harmonic reducer with torque sensing, characterized in that: The device includes a wave generator (1), a flexible bearing (2), a flexible wheel (3), an output end rigid wheel (4), a cross-roll bearing (5), and a fixed end rigid wheel (6). The flexible bearing (2) is arranged between the wave generator (1) and the flexible wheel (3) and two are arranged side by side along the axial direction of the wave generator (1). The external teeth of the flexible wheel (3) mesh with the internal teeth of the output end rigid wheel (4) and the internal teeth of the fixed end rigid wheel (6). The two flexible bearings (2) correspond to the internal teeth of the output end rigid wheel (4) and the internal teeth of the fixed end rigid wheel (6), respectively. The cross roller bearing (5) includes cross rollers (51) and bearing outer ring (52). The cross rollers (51) are disposed between the bearing outer ring (52) and the output end rigid wheel (4). The output end rigid wheel (4) serves as the inner ring of the cross roller bearing (5). The fixed end rigid wheel (6) and the bearing outer ring (52) are detachably and fixedly connected. The fixed end rigid wheel (6) has two end faces respectively provided with relief grooves (61) coaxial with the fixed end rigid wheel (6), and a connecting wall (62) is formed between the bottom of the two relief grooves (61). Several strain gauges (7) arranged in a circular array are installed on the bottom of the relief groove (61) near the output end rigid wheel (4).

2. The dual rigid wheel harmonic reducer with torque sensing according to claim 1, characterized in that: The fixed end rigid wheel (6) and the bearing outer ring (52) are integrated.

3. A dual rigid wheel harmonic reducer with torque sensing according to claim 1 or 2, characterized in that: A four-point contact ball bearing (8) is installed in the relief groove (61) away from the output end rigid wheel (4).

4. The dual rigid wheel harmonic reducer with torque sensing according to claim 1, characterized in that: The axial thickness of the connecting wall (62) along the fixed end rigid wheel (6) is 20%-70% of the length of the internal teeth of the fixed end rigid wheel (6).

5. A dual rigid wheel harmonic reducer with torque sensing according to claim 4, characterized in that: The radial length of the connecting wall (62) along the fixed end rigid wheel (6) is 20%-70% of the radial thickness of the fixed end rigid wheel (6).

6. A dual rigid wheel harmonic reducer with torque sensing according to claim 5, characterized in that: The wall thickness between the side wall of the relief groove (61) near the inner tooth of the fixed end rigid wheel (6) and the inner hole of the fixed end rigid wheel (6) is not less than twice the tooth height of the inner tooth of the fixed end rigid wheel (6).

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