Linear driver

Abstract

The linear driver comprises a shell, a linear motor, a sliding part, an output shaft and a sleeve, and the linear motor, the sliding part and the sleeve are arranged in the shell; the linear motor is located on one side of the sliding piece, and the output end of the linear motor is connected with the sliding piece. The output shaft is installed on the other side of the sliding part, a through hole is formed in the shell, and the output shaft penetrates through the through hole; the sleeve is connected to the end, close to the through hole, of the sliding piece, the sleeve is arranged on the output shaft in a sleeving mode and bears the output shaft, and at least part of the sleeve protrudes out of the sliding piece in the axial direction of the output shaft. The linear motor comprises a stator and a mover, the mover can be driven by the stator to do linear motion, the sliding piece is connected with the mover so that the sliding piece can move along with the mover, and the moving direction of the mover is parallel to the axial direction of the output shaft. The linear driver provided by the embodiment of the utility model is compact in axial structure, and the axial slippage of the output shaft is stable.

Description

Technical Field

[0001] The present application relates to the field of motors, and in particular to a linear drive. Background Art

[0002] Existing linear drives generally use rotating motors and lead screw nuts. Although this structure is low-cost and highly stable, it occupies a large axial space, which is not conducive to use in a small space. In addition, due to the large precision error of its transmission components, it is even more unfavorable for operating small workpieces.

[0003] In addition, the linear actuator using a linear drive has poor stability itself, and since the cantilever of the output shaft is large, its stability is further reduced, which is not conducive to stable output.

[0004] Therefore, there is an urgent need for a linear actuator with a compact axial structure and smooth axial sliding of the output shaft to overcome the above-mentioned defects. Utility Model Content

[0005] The purpose of the present application is to provide a linear drive with a compact axial structure and smooth axial sliding of the output shaft.

[0006] To achieve the above-mentioned purpose, an embodiment of the present application provides a linear driver, including a housing, a linear motor, a sliding member, an output shaft and a sleeve, wherein the linear motor, the sliding member and the sleeve are arranged in the housing, and the output shaft, the sliding member and the linear motor are arranged in sequence along a direction perpendicular to the axial direction of the output shaft; the linear motor is located on one side of the sliding member, and the output end of the linear motor is connected to the sliding member; the output shaft is installed on the other side of the sliding member, and the housing is provided with a through hole, and the output shaft passes through the through hole; the sleeve is connected to one end of the sliding member adjacent to the through hole, and the sleeve is sleeved on the output shaft and carries the output shaft, and the sleeve at least partially protrudes from the sliding member along the axial direction of the output shaft; the linear motor includes a stator and a mover, and the mover can perform linear motion under the drive of the stator, and the sliding member is connected to the mover so that the sliding member can follow the movement of the mover, and the movement direction of the mover is parallel to the axial direction of the output shaft.

[0007] In some embodiments of the present application, under the linkage of the sliding member, the sleeve can slide toward the through hole along the axial direction of the output shaft, and the sleeve does not extend out of the through hole.

[0008] In some embodiments of the present application, the linear drive also includes a rolling bearing and a positioning sleeve, the rolling bearing is arranged in the sleeve, and the rolling bearing is also sleeved on the output shaft; two rolling bearings are arranged at intervals along the axial direction of the output shaft; the positioning sleeve is sleeved on the output shaft, the positioning sleeve is located between the two rolling bearings along the axial direction of the output shaft, and the two rolling bearings are each abutted against the positioning sleeve along the axial direction of the output shaft.

[0009] In some embodiments of the present application, the linear drive also includes a rotary motor, which is located next to an end of the sleeve away from the through hole and connected to the sleeve, and the output shaft is connected to the rotary motor and can rotate under the drive of the rotary motor; the rotary motor includes a motor housing and a driving stator, the driving stator is arranged in the motor housing and connected to the motor housing, and the output shaft penetrates into the motor housing and can rotate under the drive of the driving stator.

[0010] In some embodiments of the present application, one end of the sleeve away from the through hole extends into the motor housing and abuts against the inner wall of the motor housing.

[0011] In some embodiments of the present application, the peripheral side of the sleeve protrudes out of the protrusion, the sliding member is connected to one side of the protrusion adjacent to the through hole, and the motor housing is connected to the other side of the protrusion away from the through hole.

[0012] In some embodiments of the present application, the output shaft is provided with an air passage running through along the axial direction of the output shaft.

[0013] In some embodiments of the present application, a nozzle structure and / or a connection structure is provided at one end of the output shaft located outside the shell.

[0014] In some embodiments of the present application, the linear drive also includes an airtight cover and an air pipe, the output shaft is provided with an air passage passing through the axial direction of the output shaft, the airtight cover is located at the end of the motor housing away from the through hole and is connected to the motor housing, the end of the output shaft located in the housing is connected to the airtight cover and communicated with the airtight cover, the air pipe is arranged at the end of the airtight cover away from the through hole and communicated with the airtight cover, so that the air pipe is communicated with the output shaft through the airtight cover.

[0015] In some embodiments of the present application, the rotary motor further comprises a magnetic rotary encoder, the magnetic rotary encoder is arranged at an end of the motor housing away from the through hole, and / or an end of the airtight cover close to the through hole, and the magnetic rotary encoder is also connected to the output shaft;

[0016] In some embodiments of the present application, the magnetic rotary encoder includes a magnetic code disk and a sensor, the magnetic code disk is arranged on the output shaft, and the sensor is connected to the motor housing and / or the airtight cover.

[0017] In some embodiments of the present application, the linear drive further comprises a slide rail fixed to the housing, the slide rail extends along the axial direction of the output shaft and is located between the output shaft and the linear motor, and the sliding member is slidably connected to the slide rail.

[0018] In some embodiments of the present application, the linear drive also includes a linear encoder, which is connected to one of the sliding member and the mover, and is also connected to the housing; the linear encoder is located on a side of the sliding member close to the linear motor.

[0019] In some embodiments of the present application, the linear encoder includes a relative code track and an absolute code track, and the relative code track and the absolute code track are arranged in parallel and each extends along the axial direction of the output shaft.

[0020] Compared with the prior art, in the linear drive of the embodiment of the present application, the output shaft, the sliding member and the linear motor are arranged in sequence along a direction perpendicular to the axial direction of the output shaft, and the linear motor is located on one side of the sliding member, the output end of the linear motor is connected to the sliding member, the output shaft is installed on the other side of the sliding member, the sliding member is connected to the mover, and the movement direction of the mover is parallel to the axial direction of the output shaft, so that the axial structure of the linear drive of the embodiment of the present application is compact and the axial sliding of the output shaft is smooth and reliable; and in the linear drive of the embodiment of the present application, the sleeve is connected to one end of the sliding member adjacent to the through hole, and the sleeve is sleeved on the output shaft and carries the output shaft, and the sleeve at least partially protrudes from the sliding member along the axial direction of the output shaft, which is beneficial to reduce the cantilever length of the output shaft, increase the smoothness of the axial sliding of the output shaft, and enhance its impact resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 FIG. 1 is a three-dimensional diagram of a linear actuator according to an embodiment of the present application.

[0023] Figure 2 for Figure 1 A perspective view of the linear drive is shown with part of the housing hidden.

[0024] Figure 3 for Figure 1 A plan view of the linear actuator shown.

[0025] Figure 4 for Figure 3 The linear drive shown is a cross-sectional view of the projection along line AA.

[0026] Figure 5 for Figure 4 A partial enlarged view of the portion indicated by B shown.

[0027] Figure 6 for Figure 5 A partial enlarged view of the portion indicated by A shown in FIG.

[0028] Figure 7 for Figure 1 A perspective view of the linear actuator is shown with the housing and the elastic member hidden. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0031] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0032] First of all, in the description of the embodiments of the present application, it needs to be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0033] Secondly, the terms "first", "second", "third", etc. are only used to distinguish descriptions, without any distinction of order or importance, and cannot be understood as indicating or implying relative importance. The characteristics specified as "first" or "second" may explicitly or implicitly include one or more of such characteristics.

[0034] Furthermore, the terms "horizontal" and "vertical" do not mean that the components must be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted; the term "along a certain direction" does not mean that it must be absolutely parallel to the direction, but can be offset, that is, it only needs to have a component in the direction.

[0035] In addition, in the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, an electromagnetic connection, or even a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0036] In addition, the “and / or” in this application, such as “Feature 1 and / or Feature 2”, refers to the three cases that it can be “Feature 1” alone, “Feature 2” alone, or “Feature 1” plus “Feature 2”. The “and / or” in this application, such as “Feature 1 and / or Feature 2”, refers to the three cases that it can be “Feature 1” alone, “Feature 2” alone, or “Feature 1” plus “Feature 2”.

[0037] See also Figure 1-7The linear actuator 1 of the embodiment of the present application includes a housing 10, a linear motor 20, a sliding member 31, an output shaft 40 and a sleeve 51. The linear motor 20, the sliding member 31 and the sleeve 51 are arranged in the housing 10; along a direction perpendicular to the axial direction of the output shaft 40, the output shaft 40, the sliding member 31 and the linear motor 20 are arranged in sequence; the linear motor 20 is located on one side of the sliding member 31, and the output end of the linear motor 20 is connected to the sliding member 31; the output shaft 40 is installed on the other side of the sliding member 31, and the housing 10 is provided with a through hole 10a , the output shaft 40 passes through the through hole 10a; the sleeve 51 is connected to one end of the sliding member 31 adjacent to the through hole 10a, and the sleeve 51 is sleeved on the output shaft 40 and carries the output shaft 40, and the sleeve 51 at least partially protrudes from the sliding member 31 along the axial direction of the output shaft 40; the linear motor 20 includes a stator 21 and a mover 22, and the mover 22 can perform linear motion under the drive of the stator 21, and the sliding member 31 is connected to the mover 22 so that the sliding member 31 can follow the mover 22, and the moving direction of the mover 22 is parallel to the axial direction of the output shaft 40. More specifically, as follows:

[0038] It should be noted that, in the present application, the linear motor 20 is a device that directly converts electrical energy into linear motion mechanical energy, and it does not require any intermediate conversion mechanism to ensure the compactness and rationality of the overall structure.

[0039] It should also be noted that in the present application, "sleeving" does not necessarily mean that two objects are in direct contact. For example, the sleeve 51 is sleeved on the output shaft 40. The sleeve 51 may serve as a sliding bearing and directly contact and support the output shaft 40. Alternatively, the sleeve 51 supports the output shaft 40 by means of a rolling bearing and does not directly contact the output shaft 40.

[0040] like Figure 1 , 2 As shown in Figures 4, 5 and 6, under the linkage of the sliding member 31, the sleeve 51 can slide along the axial direction of the output shaft 40 toward the through hole 10a, and the sleeve 51 does not extend out of the through hole 10a, so as to further reduce the cantilever length of the output shaft 40 and avoid the sleeve 51 from being damaged by the outside.

[0041] like Figure 1 , 2, 4 and 5, the linear actuator 1 of the embodiment of the present application further includes a first rolling bearing 52, the first rolling bearing 52 is arranged in the sleeve 51, and the first rolling bearing 52 is also sleeved on the output shaft 40, so that the sleeve 51 supports one end of the output shaft 40 through the first rolling bearing 52, and avoids friction between the sleeve 51 and the output shaft 40, thereby ensuring the smooth rotation of the output shaft 40; preferably, in the linear actuator 1 of the embodiment of the present application, two first rolling bearings 52 are arranged at intervals along the axial direction of the output shaft 40, so as to further ensure the support of one end of the output shaft 40 and the smooth rotation of the output shaft 40. Of course, according to actual conditions, in other embodiments, the first rolling bearings 52 can also be provided in different quantities such as one, three, four, five, etc., which can also achieve the above-mentioned effect, so it is not limited thereto.

[0042] like Figure 1 , 2 As shown in , 4 and 5, the linear drive 1 also includes a positioning sleeve 52 sleeved on the output shaft 40, the positioning sleeve 52 is located between the two first rolling bearings 52 along the axial direction of the output shaft 40, and the two first rolling bearings 52 are respectively abutted against the positioning sleeve 52 along the axial direction of the output shaft 40 to provide positioning for the two first rolling bearings 52.

[0043] like Figure 2 , 4 As shown in Figure 6, the linear actuator 1 of the embodiment of the present application further includes a rotary motor 60, which is located beside the end of the sleeve 51 away from the through hole 10a and is connected to the sleeve 51. The output shaft 40 is connected to the rotary motor 60 and can rotate under the drive of the rotary motor 60, so that the output shaft 40 can output torque. Specifically, in the linear actuator 1 of the embodiment of the present application, the rotary motor 60 includes a motor housing 61 and a driving stator 62, the driving stator 62 is disposed in the motor housing 61 and connected to the motor housing 61, the output shaft 40 penetrates the motor housing 61, and can rotate under the drive of the driving stator 62, that is, in the embodiment of the present application, the output shaft 40 is configured as a "rotating shaft" in the rotary motor 60, thereby reducing the use of couplings and facilitating the subsequent setting of the air duct 40 described.

[0044] like Figure 2 , 4 As shown in FIG. 5 , one end of the sleeve 51 away from the through hole 10a extends into the motor housing 61 and abuts against the inner wall of the motor housing 61 to provide positioning for the installation of the sleeve 51 and also to provide a fixed connection between the sleeve 51 and the motor housing 61, which can be set according to actual conditions.

[0045] like Figure 2 , 4As shown in 6, the rotating motor 60 also includes a bearing seat 71 and a second rolling bearing 72. The bearing seat 71 is located at one end of the motor housing 61 away from the through hole 10a and is connected to the motor housing 61. The second rolling bearing 72 is arranged in the bearing seat 71. The second rolling bearing 72 is also sleeved on the output shaft 40 and carries the output shaft 40, and works together with the first rolling bearing 52 to further ensure the smooth rotation of the output shaft 40.

[0046] like Figure 2 , 4 As shown in Figure 5, the circumferential side of the sleeve 51 protrudes out from the protrusion 51a, the sliding member 31 is connected to the side of the protrusion 51a adjacent to the through hole 10a, and the motor housing 61 is connected to the other side of the protrusion 51a away from the through hole 10a, so that the connection between the sleeve 51, the sliding member 31 and the rotating motor 60 is reasonable and compact.

[0047] like Figure 2 , 4 , 5 and 6, the output shaft 40 is provided with an air passage 40a, which is passed through along the axial direction of the output shaft 40, so that the output shaft 40 can provide a suction and / or blowing effect. Preferably, in the linear actuator 1 of the embodiment of the present application, the end of the output shaft 40 located outside the housing 10 is provided with a suction nozzle structure for suction. Of course, according to actual conditions, in other embodiments, the end of the output shaft 40 located outside the housing 10 can also be provided with a connection structure to connect with the outside world, so it is not limited to this.

[0048] like Figure 2 , 4 As shown in FIGS. 6 and 7 , the linear actuator 1 further includes an airtight cover 81 and an air pipe 82. The output shaft 40 is provided with an air passage 40 a which passes through the output shaft 40 in the axial direction. The airtight cover 81 is located at one end of the motor housing 61 away from the through hole 10 a and is connected to the motor housing 61. One end of the output shaft 40 located in the housing 10 is connected to the airtight cover 81 and communicates with the airtight cover 81. The air pipe 82 is provided at one end of the airtight cover 81 away from the through hole 10 a and is communicated with the airtight cover 81, so that the air pipe 82 is communicated with the output shaft 40 via the airtight cover 81.

[0049] like Figure 2 , 4 , 6 and 7, the rotary motor 60 further includes a magnetic rotary encoder 91, which is disposed between an end of the motor housing 61 away from the through hole 10a and an end of the airtight cover 81 close to the through hole 10a. The magnetic rotary encoder 91 is also connected to the output shaft 40 to detect the rotation speed of the output shaft 40. Of course, in other embodiments, the magnetic rotary encoder 91 may also be disposed only at the end of the motor housing 61 away from the through hole 10a, or at the end of the airtight cover 81 close to the through hole 10a, and the above-mentioned effect can also be achieved, so it is not limited to this.

[0050] like Figure 2 , 4 , 6 and 7, the magnetic rotary encoder 91 includes a magnetic code disc 911 and a sensor 912. The magnetic code disc 911 is disposed on the output shaft 40, and the sensor 912 is connected to the airtight cover 81 to ensure that the structure of the magnetic rotary encoder 91 is reasonable and compact. Of course, according to actual conditions, in other embodiments, the sensor 912 can also be connected to the motor housing 61 or the bearing seat 71, and the above-mentioned effect can also be achieved, so it is not limited to this.

[0051] like Figure 2 , 4 As shown in Figure 7, the linear drive 1 also includes a slide rail 32 fixed to the housing 10, the slide rail 32 extends along the axial direction of the output shaft 40 and is located between the output shaft 40 and the linear motor 20, and the sliding member 31 is slidably connected to the slide rail 32 to further ensure the accuracy and stability of the sliding member 31 sliding along the axial direction of the output shaft 40, thereby ensuring the accuracy and stability of the sliding of the output shaft 401 along the axial direction of the output shaft 40.

[0052] like Figure 7 As shown, the linear actuator 1 further includes a linear encoder 92, which is connected to the sliding member 31. The linear encoder 92 is also connected to the housing 10 to detect the axial displacement of the sliding member 31 and the output shaft 40. Of course, according to actual conditions, the linear encoder 92 can also be connected to the output shaft 40 or the mover 22, and the above-mentioned effect can also be achieved, so it is not limited to this.

[0053] like Figure 7 As shown, the linear encoder 92 is located on the side of the sliding member 31 close to the linear motor 20 to further ensure the compactness of the structure and avoid overlapping with the linear motor 20 to increase the thickness of the linear drive 1.

[0054] like Figure 7 As shown, the linear encoder 92 includes a relative code track 921 and an absolute code track 922 , which are arranged in parallel and extend along the axial direction of the output shaft 40 respectively, so that the displacement detection can be accurate and convenient.

[0055] The linear encoder 92 is an absolute encoder and has the following advantages over the incremental encoder:

[0056] (1) Incremental encoders do not have a power-off retention function, while absolute encoders can retain data after power failure;

[0057] (2) Incremental encoders have zero-point cumulative errors and poor anti-interference. The receiving device needs to be powered off and memorized when it is shut down, and the zero or reference position should be found when it is turned on. These problems can be solved by absolute encoders. General applications of incremental encoders: speed measurement, rotation direction measurement, movement angle measurement, and relative distance measurement.

[0058] (3) Incremental encoders can only remember how many steps have been taken, but cannot sense the specific position; absolute encoders can know the current position as long as they are powered on. After the absolute encoder is powered on again, it will remember the previous value without returning to the origin; in addition, the incremental encoder converts the displacement into a periodic electrical signal, and then converts the electrical signal into a counting pulse, using the number of pulses to represent the size of the displacement, while each position of the absolute encoder corresponds to a certain digital code, so its indication is only related to the starting and ending positions of the measurement, but not to the intermediate process of the measurement.

[0059] like Figure 2 and 4 As shown, the linear actuator 1 of the embodiment of the present application further includes an elastic member 33, which is disposed between the sliding member 31 and the housing 10, so that the elastic member 33 always has a tendency to drive the sliding member 31 to slide in the axial direction of the output shaft 40 in a direction away from the through hole 10a, so that the output shaft 40 always has a tendency to retract into the housing 10 under the driving action of the elastic member 33. Of course, in other embodiments, the elastic member 33 may also be disposed between the rotating motor 60 and the housing 10, or, may be disposed between the mover 22 and the housing 10. The above-mentioned effect may also be achieved through adaptive arrangement, so it is not limited thereto.

[0060] It should be noted that in the drawings, the direction indicated by arrow X is the axial direction of the output shaft 40 , and the direction indicated by arrow Y is a direction perpendicular to the axial direction of the output shaft 40 but is not limited thereto.

[0061] Compared with the prior art, in the linear actuator 1 of the embodiment of the present application, the output shaft 40, the sliding member 31 and the linear motor 20 are arranged in sequence along a direction perpendicular to the axial direction of the output shaft 40, and the linear motor 20 is located on one side of the sliding member 31, the output end of the linear motor 20 is connected to the sliding member 31, the output shaft 40 is installed on the other side of the sliding member 31, the sliding member 31 is connected to the mover 22, and the movement direction of the mover 22 is parallel to the axial direction of the output shaft 40, so that the axial structure of the linear actuator 1 of the embodiment of the present application is compact, and the axial sliding of the output shaft 40 is stable and reliable; and in the linear actuator 1 of the embodiment of the present application, the sleeve 51 is connected to one end of the sliding member 31 adjacent to the through hole 10a, and the sleeve 51 is sleeved on the output shaft 40 and carries the output shaft 40, and the sleeve 51 at least partially protrudes from the sliding member 31 along the axial direction of the output shaft 40, which is conducive to reducing the cantilever length of the output shaft 40, increasing the stability of the axial sliding of the output shaft 40, and enhancing its impact resistance.

[0062] The above disclosure is only a preferred example of the present application, and its role is to facilitate the technical personnel in this field to understand and implement it, but it cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made within the scope recorded in this application still fall within the scope covered by this application.

Claims

1. A linear actuator, characterized in that: It comprises a housing, a linear motor, a sliding member, an output shaft and a sleeve, wherein the linear motor, the sliding member and the sleeve are arranged in the housing, and the output shaft, the sliding member and the linear motor are arranged in sequence along a direction perpendicular to the axial direction of the output shaft; The linear motor is located at one side of the sliding member, and the output end of the linear motor is connected to the sliding member; The output shaft is installed on the other side of the sliding member, the housing is provided with a through hole, and the output shaft passes through the through hole; The sleeve is connected to one end of the sliding member adjacent to the through hole, and the sleeve is sleeved on the output shaft and carries the output shaft, and the sleeve at least partially protrudes from the sliding member along the axial direction of the output shaft; The linear motor includes a stator and a mover, the mover can perform linear motion under the drive of the stator, the sliding member is connected to the mover so that the sliding member can follow the movement of the mover, and the movement direction of the mover is parallel to the axial direction of the output shaft.

2. The linear actuator according to claim 1, characterized in that Under the linkage of the sliding member, the sleeve can slide toward the through hole along the axial direction of the output shaft, and the sleeve does not extend out of the through hole.

3. The linear actuator according to claim 1, wherein: The linear drive also includes a rolling bearing and a positioning sleeve, wherein the rolling bearing is arranged in the sleeve and is also sleeved on the output shaft; two rolling bearings are arranged at intervals along the axial direction of the output shaft; the positioning sleeve is sleeved on the output shaft, and the positioning sleeve is located between the two rolling bearings along the axial direction of the output shaft, and the two rolling bearings are respectively abutted against the positioning sleeve along the axial direction of the output shaft.

4. The linear actuator according to claim 1, wherein: The linear actuator further comprises a rotary motor, which is located beside an end of the sleeve away from the through hole and connected to the sleeve, the output shaft is connected to the rotary motor and can rotate under the drive of the rotary motor; the rotary motor comprises a motor housing and a driving stator, the driving stator is arranged in the motor housing and connected to the motor housing, the output shaft penetrates into the motor housing and can rotate under the drive of the driving stator.

5. The linear actuator according to claim 4, characterized in that One end of the sleeve away from the through hole extends into the motor housing and abuts against the inner wall of the motor housing.

6. The linear actuator according to claim 5, characterized in that The peripheral side of the sleeve protrudes out of the protrusion, the sliding member is connected to one side of the protrusion adjacent to the through hole, and the motor housing is connected to the other side of the protrusion away from the through hole.

7. The linear actuator according to claim 4, characterized in that The linear drive also includes an airtight cover and an air pipe. The output shaft is provided with an air passage passing through the output shaft in the axial direction. The airtight cover is located at an end of the motor housing away from the through hole and is connected to the motor housing. An end of the output shaft located in the housing is connected to the airtight cover and communicates with the airtight cover. The air pipe is provided at an end of the airtight cover away from the through hole and communicates with the airtight cover, so that the air pipe is communicated with the output shaft via the airtight cover.

8. The linear actuator according to claim 7, characterized in that The rotary motor further comprises a magnetic rotary encoder, which is arranged at an end of the motor housing away from the through hole and / or an end of the airtight cover close to the through hole, and is also connected to the output shaft.

9. The linear actuator according to claim 1, wherein: The linear drive further comprises a linear encoder, which is connected to one of the sliding member and the mover, and is also connected to the housing; the linear encoder is located on a side of the sliding member close to the linear motor.

10. The linear actuator according to claim 9, characterized in that The linear encoder includes a relative code track and an absolute code track, which are arranged in parallel and extend along the axial direction of the output shaft respectively.

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