Electric push rod

Abstract

The utility model relates to the technical field of electric push rods, in particular to an electric push rod. The utility model discloses an electric push rod which comprises a shell and a screw rod arranged in the shell, and the screw rod is driven by a gear transmission assembly. The screw rod is sequentially provided with a first threaded section used for being matched with a screw rod nut for use, a fixing section, a second threaded section and an assembling section used for being fixed to the gear transmission assembly in the axis direction, the fixing section rotates relative to the inner wall of the shell through a bearing, and the outer circle face of the second threaded section is sleeved with a locking nut; one axial end of the locking nut abuts against the bearing inner ring, and the other axial end of the locking nut abuts against the gear transmission assembly. The electric push rod has the advantage that the stability of the electric push rod during operation can be improved.

Description

Technical Field

[0001] This utility model relates to the field of electric linear actuator technology, specifically an electric linear actuator. Background Technology

[0002] Chinese patent application No. 202320683848.3 discloses a lead screw fixing structure for an electric actuator, including a lead screw. The lead screw includes a fixed section and a mating section along the axial direction. The mating section is provided with a first external thread structure and is fitted with a lead screw nut. The fixed section is fixed to the electric actuator housing near the mating section by a bearing. The fixed section is provided with a second external thread structure and is fitted with a locking nut. The fixed section is provided with a first annular groove near the mating section. The first annular groove is provided with a first shaft retaining ring. The outer diameter of the first shaft retaining ring is smaller than the outer diameter of the first external thread structure and larger than the inner diameter of the bearing. The bearing is restricted between the first shaft retaining ring and the locking nut.

[0003] In the above technical solution, the axial positions of the bearing and the locking nut are limited by two shaft retaining rings located at the axial ends of the bearing and the locking nut, respectively. However, in the above technical solution, when the shaft retaining rings are assembled with the annular groove of the lead screw, due to the unavoidable tolerances during the machining of the parts, there will inevitably be a gap between the shaft retaining rings and the annular groove of the lead screw. This will cause the lead screw to move axially during operation, affecting the stability of the electric push rod. Therefore, although the locking nut is used to form an integral structure of the lead screw, bearing, locking nut and shaft retaining rings, the overall structure still has the possibility of axial movement. Utility Model Content

[0004] The purpose of this invention is to provide an electric linear actuator that can prevent axial movement of the lead screw during operation, thereby ensuring the stability of the electric linear actuator during operation.

[0005] To achieve the above objectives, this utility model discloses an electric actuator, including a housing and a lead screw disposed within the housing. The lead screw is driven by a gear transmission assembly. The lead screw is provided sequentially along its axial direction with a first threaded section for cooperating with a lead screw nut, a fixed section, a second threaded section, and an assembly section for fixing to the gear transmission assembly. The fixed section rotates relative to the inner wall of the housing via a bearing. A locking nut is fitted on the outer surface of the second threaded section. One axial end of the locking nut abuts against the inner ring of the bearing, and the other axial end of the locking nut abuts against the gear transmission assembly.

[0006] When the electric actuator performs work, the gear transmission assembly drives the lead screw to move along the axial direction of the lead screw nut through the first threaded section. The locking nut is assembled with the lead screw through the second threaded section and limits the bearings and gear transmission assembly located at both ends of the axial direction to prevent the lead screw from moving axially due to the reaction force.

[0007] This invention, by setting a locking nut and a second threaded section for engaging with the locking nut on the lead screw, utilizes the fact that one end of the locking nut abuts against the inner ring of the bearing and the other end abuts against the gear transmission assembly. The locking nut's own dimensions effectively compensate for the gap caused by the part tolerances between the shaft retaining ring and the annular groove in the prior art, thus limiting the axial movement of the lead screw during operation. This invention has the advantage of improving the stability of the electric linear actuator during operation.

[0008] The gear transmission assembly and the lead screw are connected by any existing fixing method, such as interference fit or key connection.

[0009] Preferably, the housing contains a first annular cavity and a second annular cavity arranged sequentially along the axial direction of the lead screw. The sidewalls of the first annular cavity and the second annular cavity are parallel to the axial direction of the lead screw. The diameter of the sidewall of the second annular cavity is larger than that of the sidewall of the first annular cavity. The outer ring of the bearing is fitted with the sidewall of the first annular cavity. A bearing cover plate is fixedly provided on the bottom wall of the second annular cavity to press the bearing against the bottom wall of the first annular cavity.

[0010] By pressing the bearing with a bearing cover plate, relative movement between the outer ring of the bearing and the side wall of the first annular cavity is prevented, thus avoiding impact on the bearing's service life and the stability of the lead screw during operation.

[0011] The bearing cover is assembled to the bottom of the second annular cavity by any existing fixing method, such as screw connection, adhesive connection or welding.

[0012] Preferably, the bearing cover plate has a first lip near one end of the bearing, the first lip being used to press the outer ring of the bearing against the bottom wall of the first annular cavity.

[0013] Compared to the method where the bearing cover plate contacts both the inner and outer rings of the bearing, this method prevents the inner ring of the bearing from causing wear on the bearing cover plate, thus ensuring the service life of the bearing cover plate.

[0014] Preferably, the locking nut has a second lip near the bearing end, and the second lip abuts against the inner ring of the bearing.

[0015] This is ensured by setting a second lip.

[0016] Preferably, the outer surface of the locking nut has two relatively parallel flat parts, which makes it easier for workers to apply force to the locking nut during assembly.

[0017] This invention can limit the bearings and gear transmission components located at both ends of the axial direction, preventing the lead screw from moving axially due to the reaction force, and has the advantage of improving the stability of the electric linear actuator during operation. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of one structure of the present utility model.

[0019] Figure 2 This is a cross-sectional structural diagram of the present invention.

[0020] Figure 3 for Figure 2 A magnified schematic diagram of the structure at point A in the middle.

[0021] Figure 4 This is a schematic diagram of one structure of the locking nut of this utility model.

[0022] In the diagram: 11. Housing; 12. Lead screw; 121. Assembly section; 122. Second threaded section; 123. Fixed section; 124. First threaded section; 13. Lead screw nut; 14. Gear transmission assembly; 15. Bearing; 16. Bearing cover plate; 161. First lip; 17. Screw; 18. Locking nut; 181. Flat part; 182. Second lip; 20. Jacking tube. Detailed Implementation

[0023] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0024] Depend on Figure 1 , Figure 2 As shown, this embodiment discloses an electric actuator, including a housing 11 and a lead screw 12 disposed within the housing 11. The lead screw 12 is driven by a gear transmission assembly 14. Figure 3As shown, the lead screw 12 is provided with a first threaded section 124 for cooperating with the lead screw nut 13, a fixed section 123, a second threaded section 122, and an assembly section 121 for fixing with the gear transmission assembly 14 along the axial direction. A first annular cavity and a second annular cavity are provided sequentially along the axial direction of the lead screw 12 inside the housing 11. The sidewalls of both the first and second annular cavities are parallel to the axial direction of the lead screw 12. The diameter of the sidewall of the second annular cavity is larger than that of the sidewall of the first annular cavity. The first annular cavity corresponds to the fixed section 123. The fixed section 123 of the lead screw 12 rotates relative to the inner wall of the housing 11 via the bearing 15. The second annular cavity corresponds to the locking nut 18. The outer ring of the bearing 15 mates with the sidewall of the first annular cavity. A bearing cover plate 16 is fixedly provided on the bottom wall of the second annular cavity to press the bearing 15 against the bottom wall of the first annular cavity.

[0025] A locking nut 18 is fitted on the outer surface of the second threaded section 122 of the lead screw 12. The outer surface of the locking nut 18 has two relatively parallel flat parts 181. The locking nut 18 has a second lip 182 at one end near the bearing 15. The second lip 182 abuts against the inner ring of the bearing 15. The other axial end of the locking nut 18 abuts against the gear transmission assembly 14. The axial height of the locking nut 18 is adapted to the distance between the bearing 15 and the gear transmission assembly 14.

[0026] The bearing cover plate 16 has a first lip 161 at one end near the bearing 15. The first lip 161 is used to press the outer ring of the bearing 15 against the bottom wall of the first annular cavity.

[0027] The end of the gear transmission assembly 14 away from the locking nut 18 is limited to the lead screw 12 by a shaft retaining ring.

[0028] When installing the lead screw 12, the bearing 15 is fitted onto the fixed section 123 of the lead screw 12, and the bearing 15 is press-fitted with the side wall of the first annular cavity. Then, the bearing cover plate 16 is fixed to the bottom wall of the second annular cavity by screws 17, so that the first lip 161 of the bearing cover plate 16 abuts against the outer ring of the bearing 15. Then, the locking nut 18 is assembled onto the second threaded section 122 of the lead screw 12, and the gear transmission assembly 14 and the shaft retaining ring are assembled in sequence. Finally, the electric push rod housing 11 is installed according to the existing structure. When the electric push rod does work, the gear transmission assembly 14 drives the lead screw 12 to move the lead screw nut 13 along the axial direction of the lead screw 12 through the first threaded section 124, and then drives the top tube 20 to move through the lead screw nut 13. The locking nut 18 is assembled with the lead screw 12 through the second threaded section 122 and limits the bearing 15 and the gear transmission assembly 14 located at both ends of the axial direction to prevent the lead screw 12 from moving axially due to the reaction force.

Claims

1. An electric linear actuator, comprising a housing and a lead screw disposed within the housing, the lead screw being driven by a gear transmission assembly, characterized in that: The lead screw is provided with a first threaded section, a fixed section, a second threaded section, and an assembly section for fixing to the gear transmission assembly along the axial direction. The fixed section rotates relative to the inner wall of the housing through a bearing. A locking nut is fitted on the outer surface of the second threaded section. One axial end of the locking nut abuts against the inner ring of the bearing, and the other axial end of the locking nut abuts against the gear transmission assembly. The axial height of the locking nut is adapted to the distance between the bearing and the gear transmission assembly.

2. The electric linear actuator according to claim 1, characterized in that: The housing contains a first annular cavity and a second annular cavity arranged sequentially along the axial direction of the lead screw. The sidewalls of the first annular cavity and the second annular cavity are parallel to the axial direction of the lead screw. The diameter of the sidewall of the second annular cavity is larger than that of the sidewall of the first annular cavity. The outer ring of the bearing is fitted with the sidewall of the first annular cavity. A bearing cover plate is fixedly provided on the bottom wall of the second annular cavity to press the bearing against the bottom wall of the first annular cavity.

3. An electric linear actuator according to claim 2, characterized in that: The bearing cover plate has a first lip near one end of the bearing, and the first lip is used to press the outer ring of the bearing against the bottom wall of the first annular cavity.

4. An electric actuator according to claim 1, 2, or 3, characterized in that: The locking nut has a second lip near the bearing end, and the second lip abuts against the inner ring of the bearing.

5. An electric linear actuator according to claim 4, characterized in that: The outer surface of the locking nut has two relatively parallel flat parts.

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