Linear drive mechanism

Abstract

The present invention provides a linear drive mechanism. The linear drive mechanism comprises a housing, a front cover and a rear cover that are respectively fixed at two opposite ends of the housing, a stator disposed in the housing, and a rotor disposed in the stator and rotatably connected to the stator; the front cover is provided with a sliding bearing integrally formed with the front cover; the stator comprises an annular stator core and a winding coil fixed in the stator core; and the rotor comprises a rotating shaft and a rotor magnet. The linear drive mechanism further comprises a lead screw inserted into the rotor; the lead screw comprises a hollow lead screw nut inserted and fixed in the rotor and a central lead screw disposed in the lead screw nut and extending to pass through the front cover; and the lead screw nut is used as the rotating shaft. The linear drive mechanism in the present invention can achieve real-time control, and has high reliability, high efficiency, balanced driving force, low overall height, short length, mounting-friendly size, a simple structure, and low costs.

Description

Linear driving mechanism TECHNICAL FIELD

[0001] The present application relates to the technical field of linear driving, in particular to a linear driving mechanism applied to fingers or joints of robots. BACKGROUND

[0002] At present, robots and artificial intelligence are widely developed, and a humanoid robot is an automatic machine which can assist or even replace humans to complete dangerous, heavy and complex work. The fingers of the humanoid robot are an important part to realize actions to complete tasks.

[0003] In the related art, the finger driving structure mainly adopts a structure of a brush motor cooperating with a multi-stage planetary reducer and an output shaft. When the motor force transmission passes through the multi-stage reducer, there is an obvious hysteresis phenomenon, the real-time control performance is poor, and the efficiency of the multi-stage transmission is rapidly reduced with the increase of the number of stages. Meanwhile, the brush motor itself also has problems such as poor reliability of the brush, imbalance of three-phase resistance and torque caused by contact problems, and the output shaft is supported by the shell, which has large friction and low efficiency.

[0004] In summary, the finger driving structure in the related art has problems of poor real-time control performance and reliability, low efficiency, and unbalanced driving force.

[0005] Therefore, it is necessary to provide a linear driving mechanism to solve the above technical problems. TECHNICAL PROBLEM

[0006] The present application aims to provide a linear driving mechanism to solve the problems of poor real-time control performance and reliability, low efficiency, and unbalanced driving force of the finger driving structure in the related art. TECHNICAL SOLUTION

[0007] In order to achieve the above-mentioned purpose, the present application provides a linear driving mechanism, which comprises a shell with two open ends, a front cover and a rear cover fixed to opposite ends of the shell respectively, a stator arranged in the shell, and a rotor arranged in the stator and rotationally connected with the stator, the front cover is provided with a sliding bearing integrally formed with the front cover on one side close to the shell, the stator comprises a stator core fixed in the shell and in a circular ring shape, and a winding coil fixed in the stator core and spaced from the rotor, the winding coil drives the rotor to rotate after being energized, and the rotor comprises a rotating shaft and a rotor magnet fixedly sleeved on the outer circumferential side of the rotating shaft.

[0008] The linear drive mechanism further comprises a screw rod sleeved in the rotor; the screw rod comprises a hollow screw rod nut fixedly inserted in the rotor and a central screw rod arranged in the screw rod nut and extending to pass through the front cover, the screw rod nut serves as the rotating shaft, the screw rod nut is rotationally connected with the casing and the rear cover respectively, the central screw rod is rollingly connected with the screw rod nut through a threaded structure, and the central screw rod passes through the sliding bearing and is slidingly connected with the sliding bearing.

[0009] Preferably, a through hole is arranged at a central position of the front cover away from the casing, and the sliding bearing is arranged around the through hole; the central screw rod sequentially passes through the sliding bearing and the through hole and extends outward.

[0010] Preferably, a boss is arranged around the through hole at a side of the front cover close to the casing, and the sliding bearing is integrally formed on the boss.

[0011] Preferably, the linear drive mechanism further comprises an angular contact bearing fixedly sleeved at an end of the screw rod nut close to the front cover, and an outer periphery of the angular contact bearing is fixed to the casing.

[0012] Preferably, the angular contact bearing is a four-point angular contact bearing.

[0013] Preferably, an outer ring of the angular contact bearing is fixed to the casing by gluing, and an inner ring of the angular contact bearing is fixed to the screw rod nut by welding or gluing.

[0014] Preferably, the front cover and the sliding bearing are made of a high polymer material.

[0015] Preferably, the casing, the front cover and the rear cover are integrally connected by bolts.

[0016] Preferably, the rotating shaft is a magnetic conductive hollow shaft, the rotor magnet is a magnetic sheet, the magnetic sheet is glued on the magnetic conductive hollow shaft structure and forms a radial 4-pole or 6-pole magnetic sheet structure; or,

[0017] the rotating shaft is a magnetic conductive hollow shaft, the rotor magnet is a magnetic ring, the magnetic ring is in one or more segment structures and is fixed on the magnetic conductive hollow shaft by gluing.

[0018] Preferably, the stator core is an annular magnetic conductive steel sleeve.

[0019] Preferably, the stator core is formed by stacking a plurality of silicon steel sheets by bonding.

[0020] Preferably, the winding coil is formed by stacking and bonding a plurality of coil groups into a hollow annular ring with both ends open.

[0021] Preferably, the central screw rod comprises a screw rod body inserted into the screw nut and an extension segment protruding from one end of the screw rod body close to the front cover and penetrating through the front cover, the screw rod body and the screw nut are connected through a thread structure, and the extension segment and the sliding bearing are connected in sliding along the axial direction of the extension segment.

[0022] Preferably, the linear driving mechanism further comprises a control board fixed to the cabinet, the front cover and the rear cover respectively and spaced apart from the stator, a linear position sensor electrically connected to the control board, and a stopper fixed to the extension segment; the linear position sensor is used to collect linear movement data of the stopper and transmit the data to the control board.

[0023] Preferably, the linear position sensor comprises a sensor magnet fixed to the stopper close to the control board and a plurality of first Hall sensors fixed to the control board close to the extension segment, the plurality of first Hall sensors are spaced apart along the axial direction of the screw rod body, and any first Hall sensor is located within the magnetic field range of the sensor magnet when the first Hall sensor is directly opposite to the sensor magnet.

[0024] Preferably, a partition is arranged in the cabinet, and the stator and the control board are fixed to opposite sides of the partition respectively; the control board is fixed to the cabinet, the front cover and the rear cover by means of glue pouring.

[0025] Preferably, the linear driving mechanism further comprises an angle position sensor fixed to the control board away from the stator, the angle position sensor is located within the magnetic field range of the rotor and is used to collect the rotation angle information of the motor composed of the stator and the rotor. Advantages

[0026] Compared with the related art, the linear driving mechanism of the present application realizes linear driving by using a motor composed of a stator and a rotor in cooperation with a screw rod, and integrates the cabinet, the front cover, the rear cover, the stator core, the winding coil, the rotor, the screw nut, the central screw rod and the sliding bearing integrally formed in the front cover, so that real-time control of the linear driving mechanism can be realized, the reliability is good, the efficiency is high, the driving force is balanced, in addition, the overall height of the linear driving mechanism is low, the length is small, the installation size is friendly, the structure is simple, and the sliding bearing integrally formed with the front cover can reduce the structure required for fixing the bearing to reduce the cost. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiments description. Obviously, the drawings in the following description only show some of the embodiments of the present application, and all the other drawings obtained by those of ordinary skill in the art based on these drawings without any creative effort are within the protection scope of the present application.

[0028] Fig. 1 is a perspective structural schematic view of a linear driving mechanism provided by the embodiment of the present application;

[0029] Fig. 2 is a perspective structural exploded view of the linear driving mechanism provided by the embodiment of the present application;

[0030] Fig. 3 is a cross-sectional view along the line A-A of Fig. 1.

[0031] In the drawings, 100 is a linear driving mechanism, 1 is a casing, 101 is a partition plate, 102 is a bolt, 2 is a front cover, 21 is a sliding bearing, 22 is a through hole, 3 is a rear cover, 4 is a stator, 41 is a stator core, 42 is a winding coil, 5 is a rotor magnet, 6 is a screw rod, 61 is a screw rod nut, 62 is a central screw rod, 621 is a screw rod body, 622 is an extended section, 7 is an angular contact bearing, 8 is a control board, 9 is a linear position sensor, 91 is a sensor magnet, 92 is a first Hall sensor, 10 is a stop block, 11 is an angular position sensor, and 12 is a rolling bearing. Embodiment of the present application

[0032] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those of ordinary skill in the art without any creative effort are within the protection scope of the present application.

[0033] The embodiment of the present application provides a linear driving mechanism 100, as shown in Figs. 1 to 3, which comprises a casing 1 with two open ends, a front cover 2 and a rear cover 3 fixed to opposite ends of the casing 1 respectively, a stator 4 arranged in the casing 1, and a rotor arranged in the stator 4 and rotationally connected with the stator 4, the front cover 2 is provided with a sliding bearing 21 integrally formed with the front cover 2 on the side close to the casing 1, the stator 4 comprises a stator core 41 fixed in the casing 1 and in a circular ring shape, and a winding coil 42 fixed in the stator core 41 and spaced from the rotor, the winding coil 42 drives the rotor to rotate after being electrified, and the rotor comprises a rotating shaft and a rotor magnet 5 sleeved and fixed to the outer circumferential side of the rotating shaft.

[0034] The sliding bearing 21 is designed to be integrally formed with the front cover 2, which can make the structure of the linear driving mechanism 100 simple and reliable, reduce friction, increase efficiency, and reduce the structure required for fixing the bearing to reduce costs.

[0035] In this embodiment, the shell 1 is connected with the front cover 2 and the rear cover 3 by bolts 102 to form an integral whole.

[0036] The sliding bearing 21 can be made of non-metallic material, and the material of the front cover 2 is the same as that of the sliding bearing 21. When the sliding bearing 21 and the front cover 2 are both made of non-metallic material, they are both made of polytetrafluoroethylene or J350 high polymer material.

[0037] In this embodiment, the stator core 41 is a ring-shaped magnetic steel sleeve.

[0038] As an optional embodiment of the stator core 41, the stator core 41 can be formed by stacking multiple silicon steel sheets by bonding or anchoring.

[0039] In this embodiment, the stator core 41 is a toothless core. This design can make the motor composed of the stator 4 and the rotor have no toothed slot torque, so that the motor has small jitter when speed regulating.

[0040] As an optional embodiment of the winding coil 42, the winding coil 42 can be formed by stacking and bonding multiple groups of coils to form a hollow circular ring with open ends, specifically, by stacking and bonding 6 groups of coils to form a hollow circular ring with open ends.

[0041] In this embodiment, the rotating shaft is a magnetic hollow shaft, and the rotor magnet 5 is a magnetic sheet which is glued to the magnetic hollow shaft structure and forms a radial 4-pole magnetic sheet structure, i.e. 4 magnetic sheets. Of course, according to actual needs, the magnetic sheet is glued to the magnetic hollow shaft structure to form a radial 6-pole magnetic sheet structure, i.e. 6 magnetic sheets; in addition, the rotor magnet 5 can also be a magnetic ring, which is in one or more segments and is fixed to the magnetic hollow shaft by gluing.

[0042] Specifically, the linear driving mechanism 100 further comprises a lead screw 6 sleeved in the rotor; the lead screw 6 comprises a hollow lead screw nut 61 fixedly inserted into the rotor and a central lead screw 62 arranged in the lead screw nut 61 and extending to penetrate the front cover 2, the lead screw nut 61 serves as a rotating shaft, the lead screw nut 61 is rotatably connected with the shell 1 and the rear cover 3 respectively, the central lead screw 62 is rollingly connected with the lead screw nut 61 through a threaded structure, and the central lead screw 62 penetrates the sliding bearing 21 and is slidably connected with the sliding bearing 21.

[0043] In the embodiment, the central screw rod 62 comprises a screw rod body 621 inserted into the screw nut 61 and an extension segment 622 protruding from one end of the screw rod body 621 close to the front cover 2 and penetrating through the front cover 2, the screw rod body 621 is in rolling connection with the screw nut 61 through a threaded structure, and the extension segment 622 is in sliding connection with the sliding bearing 21 along the axial direction of the extension segment 622.

[0044] In the embodiment, a through hole 22 is arranged at the central position of the side of the front cover 2 away from the shell 1, and the sliding bearing 21 is arranged around the through hole 22; the extension segment 622 of the central screw rod 62 penetrates through the sliding bearing 21 and the through hole 22 in sequence and extends outward.

[0045] The side of the front cover 2 close to the shell 1 is provided with a boss arranged around the through hole 22, and the sliding bearing 21 is integrally formed on the boss. This design can improve the structural strength of the sliding bearing 21.

[0046] In the embodiment, the linear driving mechanism 100 further comprises an angular contact bearing 7 fixedly sleeved on the end of the screw nut 61 close to the front cover 2, and the outer periphery of the angular contact bearing 7 is fixed to the shell 1. In this way, the angular contact bearing 7 can realize the rotational connection between the screw nut 61 and the shell 1. Correspondingly, the outer periphery of the end of the screw nut 61 close to the rear cover 3 is fixed with a rolling bearing 12, and the outer periphery of the rolling bearing 12 is fixed to the rear cover 3. In this way, the rolling bearing 12 can realize the rotational connection between the screw nut 61 and the rear cover 3.

[0047] The angular contact bearing 7 is a four-point angular contact bearing, the outer ring of the angular contact bearing 7 is fixed to the shell 1 by gluing, and the inner ring of the angular contact bearing 7 is fixed to the screw nut 61 by welding or gluing.

[0048] In the embodiment, the linear driving mechanism 100 further comprises a control board 8 fixed to the shell 1, the front cover 2 and the rear cover 3 respectively and spaced apart from the stator 4, a linear position sensor 9 electrically connected to the control board 8, and a stop block 10 fixedly sleeved on the extension segment 622; the linear position sensor 9 is used to collect linear movement data of the stop block 10 and transmit the data to the control board 8. The stop block 10 is rectangular and abuts against the screw rod body 621.

[0049] The linear position sensor 9 comprises a sensor magnet 91 fixed to the side of the stop block 10 close to the control board 8 and a plurality of first Hall sensors 92 fixed to the side of the control board 8 close to the extension segment 622, the plurality of first Hall sensors 92 are spaced apart along the axial direction of the screw rod body 621, and any first Hall sensor 92 is located within the magnetic field range of the sensor magnet 91 when the first Hall sensor 92 directly faces the sensor magnet 91. Specifically, a groove is formed on the side of the stop block close to the control board 8, and the sensor magnet 91 is fixed in the groove.

[0050] The casing 1 is provided with a partition plate 101, and the stator 4 and the control board 8 are fixed on opposite sides of the partition plate 101 respectively; the control board 8 is fixed on the casing 1, the front cover 2 and the rear cover 3 by means of glue pouring.

[0051] In the embodiment, the linear driving mechanism 100 further comprises an angle position sensor 11 fixed on the side of the control board 8 away from the stator 4, and the angle position sensor 11 is located in the magnetic field range of the rotor and is used to collect the rotation angle information of the motor composed of the stator 4 and the rotor. Specifically, the angle position sensor 11 comprises one or more second Hall sensors, and the second Hall sensors are located between the rolling bearing 12 and the stator 4.

[0052] In the embodiment, the motor composed of the stator 4 and the rotor has stable thrust and small fluctuation in the required driving length range, and the driving control is simple.

[0053] The linear driving mechanism 100 in the embodiment is mainly applied to the fingers or joints of a robot.

[0054] Compared with the related art, the linear driving mechanism 100 of the present application realizes linear driving by adopting the motor composed of the stator 4 and the rotor in cooperation with the lead screw 6, and the casing 1, the front cover 2, the rear cover 3, the stator core 41, the winding coil 42, the rotor, the lead screw nut 61, the center lead screw 62 and the sliding bearing 21 integrally formed on the front cover 2 are fused, so that the real-time control of the linear driving mechanism 100 can be realized, and the reliability is good, the efficiency is high, the driving force is balanced, in addition, the overall height of the linear driving mechanism 100 is low, the length is small, the installation size is friendly, the structure is simple, and the sliding bearing 21 integrally formed on the front cover 2 can reduce the structure required by the fixed bearing, so as to reduce the cost.

[0055] The above is only the embodiment of the present application, and it should be pointed out that those skilled in the art can make improvements without departing from the inventive concept, but these all belong to the protection scope of the present application.

Claims

1. A linear drive mechanism, characterized by, The linear driving mechanism comprises a shell with two open ends, a front cover and a rear cover fixed respectively at opposite ends of the shell, a stator arranged in the shell, and a rotor arranged in the stator and rotationally connected with the stator, the front cover is provided with a sliding bearing integrally formed with the front cover on a side close to the shell, the stator comprises a stator core fixed in the shell and in a circular ring shape, and a winding coil fixed in the stator core and spaced from the rotor, the winding coil drives the rotor to rotate after being energized, and the rotor comprises a rotating shaft and a rotor magnet fixed on an outer circumferential side of the rotating shaft. The linear driving mechanism further comprises a lead screw sleeved in the rotor, the lead screw comprises a lead screw nut fixed in the rotor and in a hollow shape, and a central lead screw arranged in the lead screw nut and extending to pass through the front cover, the lead screw nut serves as the rotating shaft, the lead screw nut is rotationally connected with the shell and the rear cover respectively, the central lead screw is rollingly connected with the lead screw nut through a thread structure, and the central lead screw passes through the sliding bearing and is slidingly connected with the sliding bearing.

2. The linear drive mechanism of claim 1, wherein A through hole is arranged on a central position of the front cover away from the shell and passes through the front cover, and the sliding bearing is arranged around the through hole; and the central lead screw sequentially passes through the sliding bearing and the through hole and extends outward.

3. The linear drive mechanism of claim 2, wherein, The front cover is provided with a boss arranged around the through hole on a side close to the shell, and the sliding bearing is integrally formed on the boss.

4. The linear drive mechanism of claim 1, wherein, The linear driving mechanism further comprises an angular contact bearing fixed on an end of the lead screw nut close to the front cover, and an outer circumferential side of the angular contact bearing is fixed on the shell.

5. The linear drive mechanism of claim 4, wherein, The angular contact bearing is a four-point angular contact bearing.

6. The linear drive mechanism according to claim 4 or 5, characterized in that An outer ring of the angular contact bearing is fixed on the shell through gluing, and an inner ring of the angular contact bearing is fixed on the lead screw nut through welding or gluing.

7. The linear drive mechanism of claim 1, wherein, The front cover and the sliding bearing are made of a high polymer material.

8. The linear drive mechanism of claim 1, wherein, The shell, the front cover and the rear cover are integrally connected through bolts.

9. The linear drive mechanism of claim 1, wherein, The rotating shaft is a magnetic hollow shaft, the rotor magnet is a magnetic sheet, the magnetic sheet is glued on the magnetic hollow shaft structure and forms a radial 4-pole or 6-pole magnetic sheet structure; or The rotating shaft is a magnetic hollow shaft, the rotor magnet is a magnetic ring, the magnetic ring is in one or more segment structures and is fixed on the magnetic hollow shaft through gluing.

10. The linear drive mechanism of claim 1, wherein, The stator core is an annular magnetic steel sleeve.

11. The linear drive mechanism of claim 1, wherein, The stator core is formed by stacking a plurality of silicon steel sheets through gluing.

12. The linear drive mechanism of claim 1, wherein, The winding coil is formed by stacking and gluing a plurality of coils into a hollow annular shape with two open ends.

13. The linear drive mechanism of claim 1, wherein, The central lead screw comprises a lead screw body inserted into the lead screw nut and an extension segment formed by protruding and extending from an end of the lead screw body close to the front cover and passing through the front cover, the lead screw body is rollingly connected with the lead screw nut through a thread structure, and the extension segment is slidingly connected with the sliding bearing along an axial direction of the extension segment.

14. The linear drive mechanism of claim 13, wherein, The linear driving mechanism further comprises a control board fixed to the casing, the front cover and the rear cover respectively and spaced apart from the stator, a linear position sensor electrically connected to the control board, and a stopper fixed to the extension section in a sleeving manner; the linear position sensor is used to collect linear movement data of the stopper and transmit the data to the control board.

15. The linear drive mechanism of claim 14, wherein, The linear position sensor comprises a sensor magnet fixed to the stopper near the control board and a plurality of first Hall sensors fixed to the control board near the extension section; the first Hall sensors are spaced apart along the axial direction of the screw body, and any first Hall sensor is located within the magnetic field range of the sensor magnet when the first Hall sensor is directly opposite to the sensor magnet.

16. The linear drive mechanism of claim 14, wherein, The casing is provided with a partition plate, and the stator and the control board are fixed to opposite sides of the partition plate respectively; the control board is fixed to the casing, the front cover and the rear cover respectively by means of glue pouring and sealing.

17. The linear drive mechanism of claim 14, wherein, The linear driving mechanism further comprises an angle position sensor fixed to the control board away from the stator; the angle position sensor is located within the magnetic field range of the rotor and is used to collect rotation angle information of the motor composed of the stator and the rotor.

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