Linear driving mechanism

Abstract

Provided in the present invention is a linear driving mechanism. The linear driving mechanism comprises: a shell, which is provided with openings at two ends thereof; a front cover and a rear cover, which are respectively fixed to the two opposite ends of the shell; a stator, which is arranged inside the shell; and a hollow rotor, which is arranged in the stator and is rotatably connected to the stator. The linear driving mechanism further comprises a rolling lead screw which is sleeved inside the rotor, wherein the rolling lead screw comprises a lead screw nut which is fixed in the rotor, and a central lead screw which is arranged on the inner peripheral side of the lead screw nut and penetrates the front cover, the lead screw nut being rotatably connected to the central lead screw; and the stator drives the rotor to rotate so as to drive the lead screw nut to rotate, such that the rotation of the lead screw nut drives the central lead screw to realize a linear telescopic motion. Compared with the prior art, the linear driving mechanism provided in the present invention has a good linear driving effect, a good real-time controllability, a high multi-stage transmission efficiency and a high reliability, and saves on a mounting space.

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. BACKGROUND

[0002] With the rapid development of artificial intelligence and robot industry, the fingers of humanoid robots are an important part to complete tasks. Due to the requirements of space and energy saving, linear actuators are required to be more integrated, smaller in size, higher in carrying capacity and faster in response. Linear driving mechanism is a kind of linear actuator, which uses screw rod as the driving part, and the nut is used for linear output, that is, the nut does not rotate but extends and retracts along the axial direction, and the screw rod rotates. TECHNICAL PROBLEM

[0003] In the related art, the finger driving mechanism adopts a brush motor and a multi-stage planetary reducer structure. The motor force transmission has obvious hysteresis after multi-stage reduction, and the real-time control performance is poor. Moreover, the efficiency of multi-stage transmission decreases rapidly with the increase of the number of stages. The brush motor itself also has the problems of poor reliability of the brush, unbalanced three-phase resistance caused by contact problems, and unbalanced torque. At the same time, in order to ensure the safety of the system, the motor stator outer diameter and the nut outside must be constrained in a whole shell, which increases the overall size of the linear actuator.

[0004] Therefore, it is necessary to provide a new linear driving mechanism to solve the above technical problems. TECHNICAL SCHEME

[0005] The purpose of the present application is to provide a linear driving mechanism which has good linear driving effect, good real-time control performance, high multi-stage transmission efficiency, high reliability and saves installation space.

[0006] In order to achieve the above 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 respectively at opposite ends of the shell, a stator arranged in the shell, and a hollow rotor arranged in the stator and rotatably connected with the stator; the linear driving mechanism further comprises a rolling screw rod sleeved in the rotor.

[0007] The rolling screw rod comprises a screw rod nut fixed in the rotor and a central screw rod arranged on the inner circumferential side of the screw rod nut and penetrating the front cover, and the screw rod nut is rotatably connected with the central screw rod; the stator drives the rotor to rotate to drive the screw rod nut to rotate, so that the screw rod nut drives the central screw rod to realize linear extension and retraction.

[0008] Preferably, the screw nut comprises a hollow nut body fixed in the rotor and a first thread structure formed on the inner circumferential side of the nut body;

[0009] The central screw rod comprises a central screw rod body provided in the nut body and provided with a second thread structure on the outer circumferential side, and an extension end recessed from one end of the central screw rod body close to the front cover and extended to form, the first thread structure is screwed with the second thread structure, and the extension end close to the front cover penetrates the front cover.

[0010] Preferably, the linear drive mechanism further comprises a rectangular-shaped stopper, the stopper is fixed on the extension end and abuts against the central screw rod body, and the extension end where the stopper is located forms a sliding connection with the front cover along the axial direction of the central screw rod body.

[0011] Preferably, the linear drive mechanism further comprises a control board and a linear position sensor, the control board is fixed on the shell and the front cover respectively, the linear position sensor is electrically connected with the control board, and the linear position sensor is used to collect linear movement data of the stopper.

[0012] Preferably, the linear position sensor comprises a linear sensor magnet embedded on the side of the stopper close to the control board and at least one Hall sensor fixed on the side of the control board close to the central screw rod, and the Hall sensor is located within the magnetic field range of the linear sensor magnet.

[0013] Preferably, the linear position sensor comprises a spring fixed on the side of the stopper close to the control board and a long strip-shaped conductor resistor fixed on the side of the control board close to the central screw rod, the spring slides on the surface of the conductor resistor along with the stopper, and the linear extension length of the extension end is collected by the difference of the conductor resistor at different positions.

[0014] Preferably, the stator comprises a stator core fixed on the side of the shell close to the rolling screw rod and a coil winding fixed in the stator core, the coil winding is spaced from the rotor, and the coil winding drives the rotor to rotate after being electrified.

[0015] Preferably, the rotor is a magnetically conductive hollow shaft structure, and the permanent magnet arranged on the magnetically conductive hollow shaft structure is a radial 4-pole or 6-pole magnetic ring structure.

[0016] Preferably, the rotor is a magnetically conductive hollow shaft structure, and the permanent magnet arranged on the magnetically conductive hollow shaft structure is a magnetic sheet structure, the magnetic sheet structure is pasted on the magnetically conductive hollow shaft structure to form a radial 4-pole or 6-pole magnetic field.

[0017] Preferably, the linear driving mechanism further comprises an angle position sensor, the angle position sensor comprises a collecting part fixed to the back cover and a rotating part fixed to the screw nut near the end of the back cover, and the collecting part and the rotating part are arranged in opposite intervals.

[0018] Preferably, the angle position sensor has two Hall sensor chips, the two Hall sensor chips are respectively located at the end of the control panel away from the linear driving mechanism and in the radial direction of the rotor, and the rotor angle position of the motor is recognized by sensing the angle phase signal of the magnetic field of the rotor magnet.

[0019] Preferably, the linear driving mechanism further comprises a first bearing and a second bearing, the first bearing and the second bearing are respectively sleeved and fixed to the two ends of the screw nut, and the outer periphery of the first bearing and the outer periphery of the second bearing are respectively fixed to the cabinet.

[0020] Preferably, the cabinet has an open structure at both ends, and the cabinet, the front cover and the back cover are connected into one body by bolts.

[0021] Preferably, the cabinet comprises a front cabinet and a rear cabinet, the rear cabinet is integrated into the back cover, and the front cover, the front cabinet and the back cover integrated with the rear cabinet are connected into one body by bolts. Beneficial effects

[0022] Compared with the prior art, in the linear driving mechanism of the present application, the rolling screw is sleeved in the rotor, the rolling screw comprises a screw nut fixed in the rotor and a central screw arranged on the inner periphery side of the screw nut and penetrating the front cover, and the screw nut and the central screw are rotationally connected; the stator drives the rotor to rotate to drive the screw nut to rotate, so that the screw nut drives the central screw to realize linear extension and retraction; the motor and the motion mechanism are directly driven, which is easy to control, has high system reliability, low overall height, small length and friendly installation size. Further, the cost is saved and the installation space is saved. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0024] Fig. 1 is a perspective structural schematic view of the linear driving mechanism provided by the embodiment one of the present application;

[0025] Fig. 2 is a perspective structural exploded view of the linear driving mechanism provided by the embodiment one of the present application;

[0026] Fig. 3 is a cross-sectional view along line A-A of Fig. 1;

[0027] Fig. 4 is a perspective view of a linear drive mechanism according to a second embodiment of the present application;

[0028] Fig. 5 is a cross-sectional view along line B-B of Fig. 4.

[0029] In the drawings, 100 is a linear drive mechanism, 1 is a housing, 2 is a front cover, 3 is a rear cover, 4 is a stator, 41 is a stator core, 42 is a coil winding, 5 is a rotor, 6 is a rolling screw, 61 is a screw nut, 611 is a screw nut body, 612 is a first thread structure, 62 is a central screw, 621 is a central screw body, 622 is a second thread structure, 623 is an extended end, 7 is a stop block, 71 is a stop block body, 72 is a slot, 8 is a control board, 9 is a linear position sensor, 91 is a linear sensor magnet, 92 is a Hall sensor, 93 is a spring sheet, 94 is a conductor resistor, 10 is an angular position sensor, 101 is a rotating portion, 102 is a collection portion, 11 is a first bearing, 12 is a second bearing, and 13 is a magnet seat. Embodiments of the present application

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in 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 other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0031] Embodiment one

[0032] In combination with Figs. 1 to 3, the linear drive mechanism 100 according to the embodiments of the present application comprises a housing 1 with two open ends, a front cover 2 and a rear cover 3 fixed to opposite ends of the housing 1 respectively, a stator 4 arranged in the housing 1, and a hollow rotor 5 arranged in the stator 4 and rotationally connected with the stator 4. The linear drive mechanism 100 further comprises a rolling screw 6 sleeved in the rotor 5.

[0033] The front cover 2, the housing 1 and the rear cover 3 are provided with four circular holes at the positions of four corners, and the front cover 2, the housing 1 and the rear cover 3 are fixedly connected by four long bolts in series. The long bolt connection facilitates disassembly and assembly.

[0034] The rolling screw 6 comprises a screw nut 61 fixed in the rotor 5 and a central screw 62 arranged at the inner circumferential side of the screw nut 61 and penetrating the front cover 2, and the screw nut 61 is rotationally connected with the central screw 62; the stator 4 drives the rotor 5 to rotate to drive the screw nut 61 to rotate, so that the screw nut 61 drives the central screw 62 to realize linear extension and contraction. The motor is directly driven with the motion mechanism, which is easy to control, has high system reliability, low overall height, small length and friendly installation size. Further, the cost is saved and the installation space is saved.

[0035] In the embodiment, the screw nut 61 comprises a hollow nut body 611 fixed in the rotor 5 and a first threaded structure 612 formed at the inner circumferential side of the nut body 611. The central screw 62 comprises a central screw body 621 arranged in the nut body 611 and provided with a second threaded structure 622 at the outer circumferential side, and an extension end 623 recessed from one end of the central screw body 621 close to the front cover 2 and extended to form, the first threaded structure 612 is screwed with the second threaded structure 622, and the extension end 623 penetrates the front cover 2 at one end close to the front cover 2. The rotor 5 drives the screw nut 61 to rotate, and the first threaded structure 612 and the second threaded structure 622 are screwed to drive the central screw 62 to realize linear extension and contraction during the rotation of the screw nut 61.

[0036] Optionally, the extension end 623 and the central screw body 621 form a T-shaped screw structure, the rotor 5 directly drives the T-shaped screw, which is high in efficiency and simple in structure; at the same time, the T-shaped screw has a certain locking force and is not easy to fall off.

[0037] In the embodiment, the linear drive mechanism 100 further comprises a rectangular stopper 7 fixed to the extension end 623 and abutting against the central screw body 621, and the extension end 623 where the stopper 7 is located forms a sliding connection with the front cover 2 along the axial direction of the central screw body 621.

[0038] Preferably, a sliding bearing is sleeved on the side of the front cover 2 close to the central screw body 621, and the sliding bearing forms a sliding connection with the extension end 623. In this way, the sliding effect is improved.

[0039] In the embodiment, the linear drive mechanism 100 further comprises a control board 8 and a linear position sensor 9, the control board 8 is fixed to the cabinet 1 and the front cover 2 respectively, the linear position sensor 9 is electrically connected with the control board 8, and the linear position sensor 9 is used to collect linear movement data of the stopper 7. Optionally, the control board 8 is a flexible circuit control board (PCB).

[0040] The linear position sensor 9 includes a spring piece 93 fixed to the side of the control plate 8 close to the stopper 7 and a long strip-shaped conductor resistor 94 fixed to the side of the control plate 8 close to the central screw rod 62. The spring piece 93 slides on the surface of the conductor resistor 94 along with the stopper 7. The linear extension length of the extension end 623 is collected by the difference of the conductor resistor 94 at different positions.

[0041] The stator 4 includes a stator core 41 fixed to the side of the shell 1 close to the rolling screw rod 6 and a coil winding 42 fixed in the stator core 41. The coil winding 42 is spaced from the rotor 5. The coil winding 42 drives the rotor 5 to rotate after being energized.

[0042] Optionally, the stator core 41 is an annular magnetic steel sleeve. The stator core 41 is made of silicon steel sheets and is bonded into a circular ring. The stator core 41 is made of silicon steel sheets and is riveted into a circular ring.

[0043] The stator 4 is a toothless slot structure, the motor has no tooth slot torque, and the motor has small jitter when speed regulating. 5. The motor driving force is stable, the thrust is stable in the required driving length range, the fluctuation is small, and the driving control is simple.

[0044] The coil winding 42 is a coil circular ring with both ends open, which is composed of six coils stacked and bonded.

[0045] The rotor 5 is a magnetically conductive hollow shaft structure, and the permanent magnet installed on the magnetically conductive hollow shaft structure is a radial 4-pole or 6-pole magnetic ring structure. The rotor 5 is a permanent magnet magnetic ring structure, which is simple in structure, has no brush friction, and has fast dynamic response.

[0046] The rotor 5 is a magnetically conductive hollow shaft structure, and the permanent magnet installed on the magnetically conductive hollow shaft structure is a magnetic sheet structure. The magnetic sheet structure is pasted on the magnetically conductive hollow shaft structure to form a radial 4-pole or 6-pole magnetic field.

[0047] The material of the rotor 5 is neodymium iron boron, and the performance grade is greater than or equal to N45H.

[0048] The linear drive mechanism 100 further includes an angle position sensor 10. The angle position sensor 10 includes a collection part 102 fixed to the back cover 3 and a rotating part 101 fixed to the end of the screw nut 61 close to the back cover 3. The collection part 102 is arranged in opposite spaced relation to the rotating part 101. The angle position sensor 10 is used to provide angle information for motor control.

[0049] The angle position sensor 10 has two Hall sensor chips, which are located at one end of the control panel away from the linear driving mechanism 100 and in the radial direction of the rotor 5, and the angle phase signal of the magnetic field of the rotor magnet is inducted to identify the rotor angle position of the motor.

[0050] The linear driving mechanism 100 further includes a magnet base 13 fixed to one end of the screw nut 61 close to the rear cover 3, and the rotating part 101 is fixed in the magnet base 13.

[0051] The linear driving mechanism 100 further includes a first bearing 11 and a second bearing 12, which are respectively sleeved and fixed to both ends of the screw nut 61, and the outer periphery of the first bearing 11 and the outer periphery of the second bearing 12 are respectively fixed in the machine shell 1.

[0052] Optionally, the first bearing 11 and the second bearing 12 are both rolling bearings.

[0053] The machine shell 1 has an open structure at both ends, and the machine shell 1, the front cover 2 and the rear cover 3 are connected into one body by bolts.

[0054] The machine shell 1 includes a front section and a rear section, and the rear section is integrated into the rear cover 3, and the front cover 2, the front section and the rear cover 3 are connected into one body by bolts.

[0055] Example Two

[0056] As shown in FIGS. 1-5, the basic structure of Example Two is the same as that of Example One, and the technical effects are the same, and the difference is that: the linear position sensor 9 includes a linear sensor magnet 91 embedded on one side of the stop block 7 close to the control panel 8 and at least one Hall sensor 92 fixed on one side of the control panel 8 close to the center screw 62, and the Hall sensor 92 is located in the magnetic field range of the linear sensor magnet 91.

[0057] The stop block 7 includes a stop block body 71 sleeved on the protruding end 623 and a slot 72 recessed from one side of the stop block body 71 close to the control panel 8 to the other side away from it, and the linear sensor magnet 91 is fixed in the slot 72.

[0058] Optionally, the linear sensor magnet 91 can be directly pasted on the protruding end 623 and located in the original position of the stop block 7 to save cost.

[0059] In this embodiment, the angle position sensor 10 is fixed to the control panel 8.

[0060] In this embodiment, the linear driving mechanism 100 is applied to the electric driving linear actuator of the robot dexterous finger or joint, so that the integration degree is high and the process is simplified.

[0061] Compared with the prior art, in the linear driving mechanism of the application, the rolling screw is sleeved in the rotor, the rolling screw comprises a screw nut fixed in the rotor and a central screw rod arranged on the inner circumferential side of the screw nut and penetrating the front cover, and the screw nut is rotationally connected with the central screw rod; the stator drives the rotor to rotate to drive the screw nut to rotate, so that the screw nut drives the central screw rod to realize linear extension and retraction; the motor is directly driven with the motion mechanism, which is easy to control, has high system reliability, low overall height, small length and friendly installation size, and further saves cost and installation space.

[0062] The above only describes the embodiments of the application, and it should be pointed out that those skilled in the art can make improvements without departing from the concept of the application, and these improvements are within the protection scope of the application.

Claims

1. A linear drive mechanism comprising a housing with openings at both ends, a front cover and a rear cover fixed to opposite ends of the housing, a stator disposed within the housing, and a hollow rotor disposed within the stator and rotatably connected to the stator; characterized in that: The linear drive mechanism further includes a rolling screw sleeved inside the rotor; The rolling screw includes a screw nut fixed in the rotor and a center screw arranged on the inner circumference of the screw nut and passing through the front cover, and the screw nut forms a rotational connection with the center screw; the stator drives the rotor to rotate to drive the screw nut to rotate, so that the screw nut rotates and drives the center screw to realize linear telescopic motion.

2. The linear drive mechanism according to claim 1, wherein: The screw nut includes a hollow nut body fixed in the rotor and a first thread structure formed on the inner circumference of the nut body; The center screw includes a center screw body arranged in the nut body and provided with a second threaded structure on the outer periphery, and an extended end extended from one end of the center screw body close to the front cover, the first threaded structure is threadedly connected to the second threaded structure, and the end of the extended end close to the front cover passes through the front cover.

3. The linear drive mechanism according to claim 2, wherein: The linear drive mechanism also includes a rectangular block, which is sleeved and fixed on the protruding end and abuts against the central screw body. The protruding end where the block is located forms a sliding connection with the front cover for axial movement along the central screw body.

4. The linear drive mechanism according to claim 3, wherein: The linear drive mechanism further includes a control board and a linear position sensor. The control board is fixed to the housing and the front cover respectively. The linear position sensor is electrically connected to the control board. The linear position sensor is used to collect linear movement data of the block.

5. The linear drive mechanism according to claim 4, characterized in that: The linear position sensor includes a linear sensor magnet embedded in the side of the block close to the control board and at least one Hall sensor fixed to the side of the control board close to the center screw, and the Hall sensor is located within the magnetic field range of the linear sensor magnet.

6. The linear drive mechanism according to claim 4, characterized in that: The linear position sensor includes a spring fixed to the side of the block close to the control board and a long strip of conductor resistor fixed to the side of the control board close to the center screw rod. The spring slides on the surface of the conductor resistor along with the block, and the linear extension length of the extension end is collected through the difference in the conductor resistance at different positions.

7. The linear drive mechanism according to claim 1, wherein: The stator includes a stator core fixed to a side of the housing close to the rolling screw and a coil winding fixed in the stator core. The coil winding is spaced apart from the rotor, and the coil winding drives the rotor to rotate when energized.

8. The linear drive mechanism according to claim 1, wherein: The rotor is a magnetic hollow shaft structure, and the permanent magnet installed on the magnetic hollow shaft structure is a radial 4-pole or 6-pole magnetic ring structure.

9. The linear drive mechanism according to claim 1, wherein: The rotor is a magnetic hollow shaft structure, and the permanent magnet mounted on the magnetic hollow shaft structure is a magnetic sheet structure. The magnetic sheet structure is adhered to the magnetic hollow shaft structure to form a radial 4-pole or 6-pole magnetic field.

10. The linear drive mechanism according to claim 4, characterized in that: The linear drive mechanism further includes an angular position sensor, which includes a collecting portion fixed to the rear cover and a rotating portion fixed to one end of the screw nut close to the rear cover, wherein the collecting portion and the rotating portion are arranged relative to each other.

11. The linear drive mechanism according to claim 10, characterized in that: The angular position sensor has two Hall sensor chips, which are respectively located at one end of the control board away from the linear drive mechanism and in the radial direction of the rotor. The angular position of the motor's rotor is identified by sensing the angular phase signal of the rotor magnet's magnetic field.

12. The linear drive mechanism according to claim 1, wherein: The linear drive mechanism further includes a first bearing and a second bearing. The first bearing and the second bearing are respectively sleeved and fixed on both ends of the screw nut. The outer periphery of the first bearing and the outer periphery of the second bearing are respectively fixed in the housing.

13. The linear drive mechanism according to claim 1, wherein: The housing is a structure with openings at both ends, and the housing, the front cover and the rear cover are connected as a whole by bolts.

14. The linear drive mechanism according to claim 1, wherein: The housing includes a front housing and a rear housing, the rear housing is integrated into the rear cover, and the front cover, the front housing, and the rear cover integrated with the rear housing are connected into a whole using bolts.

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