Compact steering electric cylinder

Abstract

This application relates to the field of electric cylinder technology, and more particularly to a compact steering electric cylinder, comprising a cylinder barrel and a nut, the nut being rotatably connected inside the cylinder barrel, with a transmission gear coaxially disposed on the outer side of the nut; a screw, the screw penetrating the cylinder barrel and coaxially threaded with the nut, the screw sliding along the axial direction of the cylinder barrel; and a motor, the motor transmitting power to the transmission gear through a transmission assembly, for driving the transmission gear and the nut to rotate. This application achieves bidirectional rod extension by using the rotation of the nut to drive the linear movement of the screw, eliminating the need for a piston rod structure, thereby shortening the axial length of the electric cylinder, and using a sliding rod bushing to provide support for the screw, improving the stability of the rod extension. Furthermore, by placing the transmission gear on the outer wall of the nut, the nut and the transmission gear form a single component, further shortening the axial length, resulting in a more compact structure and providing a solution for use in confined installation spaces.

Description

Technical Field

[0001] This application relates to the field of electric cylinder technology, and more particularly to a compact electric steering cylinder. Background Technology

[0002] Current forklift steering mechanisms generally use hydraulic cylinders or two electric cylinders to drive the steering. After prolonged use, hydraulic cylinders are prone to seal failure, leakage leading to contamination. At the same time, the thrust and speed of the cylinder cannot be fed back and displayed in real time, forming a closed-loop control, making it difficult to achieve precise speed control and high-speed response.

[0003] Existing electric cylinder drive solutions use dual electric cylinder drive or single motor drive structures where piston rods on both sides move. Existing electric cylinder structures are costly and require more installation space, which is not conducive to the installation of steering structures. Utility Model Content

[0004] The technical problem this invention aims to solve is that existing electric cylinders are difficult to adapt to the limited installation space in the steering structure of forklifts.

[0005] Therefore, this utility model provides a compact electric steering cylinder.

[0006] The technical solution adopted by this utility model to solve its technical problem is:

[0007] A compact electric steering cylinder, including

[0008] The cylinder barrel has bearing caps at both ends;

[0009] A nut, which is rotatably connected inside the cylinder, and a transmission gear is coaxially arranged on the outside of the nut;

[0010] A screw rod passes through the cylinder barrel and bearing cover, and is coaxially threaded with a nut. The screw rod slides along the axial direction of the cylinder barrel. A dust cover is connected between the end of the screw rod and the bearing cover, and the dust cover is placed on the screw rod.

[0011] The motor transmits power through a transmission assembly and a transmission gear, and is used to drive the transmission gear and nut to rotate.

[0012] Furthermore, the nut is rotatably mounted inside the cylinder via a tapered roller bearing.

[0013] Furthermore, a first adjusting shim is provided between the bearing cap and the cylinder.

[0014] Furthermore, a sliding bushing is provided between the screw and the bearing cap.

[0015] Furthermore, a helical raceway can be formed between the screw and the nut, and balls are disposed within the helical raceway, thus forming a ball screw structure between the screw and the nut.

[0016] Furthermore, the transmission assembly includes a motor gear, a first gear, and a second gear. A housing is connected to the cylinder, and the motor is connected to the housing. The motor gear is coaxially connected to the output shaft of the motor. A transmission shaft is provided inside the housing. The axes of the transmission shaft, the output shaft, and the nut are all parallel to each other. The first gear and the second gear are coaxially arranged on the transmission shaft. The first gear meshes with the motor gear, and the second gear meshes with the transmission gear.

[0017] Furthermore, a shaft end retaining ring is provided at the end of the output shaft.

[0018] Furthermore, a deep groove ball bearing is provided between the drive shaft and the housing, and a spacer is provided between the end face of the deep groove ball bearing and the first gear and the second gear.

[0019] Furthermore, the motor is a permanent magnet synchronous motor.

[0020] The beneficial effects of this utility model are as follows: Firstly, this application utilizes the rotation of the nut to drive the linear movement of the screw to achieve bidirectional rod delivery, eliminating the need for a piston rod structure and thus shortening the axial length of the electric cylinder. Furthermore, the sliding rod bushing provides support for the screw, improving the stability of the rod delivery. Additionally, by placing the transmission gear on the outer wall of the nut, the nut and transmission gear form a single component, further shortening the axial length and resulting in a more compact structure, providing a solution for use in confined installation spaces.

[0021] Furthermore, compared to existing technologies that connect the screw and piston rod, the solution eliminates the piston rod and directly connects the screw to the rod head. Since the screw is no longer connected to the piston rod via threads, the rigidity is greatly improved.

[0022] The single-motor electric cylinder technical solution in this application has two advantages. First, since it does not use hydraulic oil for drive, there is no risk of oil leakage, and there is no need to replace easily damaged parts such as seals, thus reducing maintenance costs. Second, the electric steering cylinder is driven by a permanent magnet synchronous motor, which can control the thrust and speed of the piston rod through a built-in rotary transformer. Furthermore, the permanent magnet synchronous motor does not require an oil pump and circulating oil circuit, so it is easy to install, has higher precision, and can save costs.

[0023] The screw sealing structure of this utility model patent uses a dust cover, which reduces the use of dust rings and rod sealing rings, thereby reducing the friction of the sealing components, improving the transmission efficiency of the electric cylinder, and saving energy. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] Figure 1 This is a schematic diagram of the structure of the compact electric steering cylinder in this utility model.

[0026] Figure 2 This is a schematic diagram of the installation structure of the base plate in this utility model.

[0027] In the diagram: 1. Cylinder; 2. Nut; 3. Screw; 4. Foot plate; 5. Tapered roller bearing; 6. Bearing cap; 7. First adjusting shim; 8. Sliding bushing; 9. Rod head; 10. Dust cover; 11. Motor; 12. Housing; 13. Transmission gear; 14. Motor gear; 15. First gear; 16. Second gear; 17. Transmission shaft; 18. Deep groove roller bearing; 19. Shaft end retaining ring; 20. Spacer; 21. Waterproof outer plug; 22. Second adjusting shim; 23. Flange. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the present invention, and therefore only show the components relevant to the present invention.

[0029] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0030] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0031] A compact electric steering cylinder includes a cylinder barrel 1, a nut 2, a screw 3, and a power unit.

[0032] A base plate 4 is provided on the cylinder 1 for stable installation of the cylinder 1. The base plate 4 is connected to the cylinder 1 by screws. The screws are internal hexagonal head screws, and a spring washer is provided between the head of the screw and the base plate 4.

[0033] Nut 2 is installed inside cylinder 1 via tapered roller bearing 5. Tapered roller bearing 5 is used to support nut 2. Bearing caps 6 are provided at both ends. A first adjusting shim 7 is provided between bearing cap 6 and cylinder 1. A flange 23 is provided on the end face of bearing cap 6 near cylinder 1.

[0034] The screw 3 passes through the bearing cap 6, cylinder 1, and nut 2. The screw 3 and nut 2 are threaded together. Furthermore, a helical raceway can be formed between the screw 3 and nut 2, and balls are arranged in the helical raceway, thus forming a ball screw structure between the screw 3 and nut 2, improving the smoothness of the screw 3's axial movement. Sliding bushings 8 are provided between both ends of the screw 3 and the bearing cap 6. A rod head 9 is connected to the end of the screw 3. A second adjusting shim 22 is provided between the rod head 9 and the screw 3. A dust cover 10 is connected between the rod head 9 and the bearing cap 6. The dust cover 10 can be set as a zipper-type dust cover 10. The dust cover 10 covers the screw 3 to prevent external dust from entering between the screw 3 and the cylinder 1.

[0035] The power unit includes a motor 11, a housing 12, a transmission assembly, and a transmission gear 13. The transmission assembly includes a motor 11 gear, a first gear 15, and a second gear 16. The housing 12 is connected to and communicates with the side wall of the cylinder 1. The motor 11 is connected to the housing 12 and is a permanent magnet synchronous motor 11. The output shaft of the motor 11 is located inside the housing 12. The motor 11 gear is coaxially connected to the output shaft of the motor 11. A transmission shaft 17 is provided inside the housing 12. The axes of the transmission shaft 17, the output shaft, and the nut 2 are all parallel to each other. The transmission shaft 17 is located between the nut 2 and the output shaft. The first gear 15 and the second gear 16 are coaxially mounted on the transmission shaft 17. The transmission gear 13 is coaxially mounted on the outer side wall of the nut 2 and is integrally formed with the nut 2. The first gear 15 meshes with the motor 11 gear, and the second gear 16 meshes with the transmission gear 13.

[0036] Furthermore, the housing 12 may include a chassis and a cover for easy maintenance. A waterproof outer plug 21 is provided on the housing 12 to prevent water from entering the housing 12. In order to improve the stability of the gears of the motor 11, a shaft end retaining ring 19 is provided at the end of the output shaft to limit the axial displacement of the gears of the motor 11. A deep groove ball bearing is provided between the transmission shaft 17 and the housing 12. A spacer 20 is provided between the end face of the deep groove ball bearing and the first gear 15 and the second gear 16 to prevent gear wear.

[0037] The electric cylinder described in this application can replace hydraulic cylinders for wheel steering in electric forklifts. Unlike conventional electric cylinders that use a lead screw to drive the nut 2 and piston linearly, this new structure uses the nut 2 to drive the lead screw for reciprocating linear motion and does not require an additional anti-rotation structure. The nut 2, in addition to its internal raceway, has a toothed outer ring that can mesh with gears.

[0038] When motor 11 rotates, it drives the gear of motor 11 to rotate clockwise, which in turn drives nut 2 to rotate through the transmission assembly. Nut 2 is supported by tapered roller bearings 5 ​​on both sides, so nut 2 rotates around a fixed axis, thereby driving screw 3 to retract linearly to the left or right. When nut 2 rotates and drives screw 3, both sides of screw 3 are connected to the load mechanism through rod head 9, which restricts the rotational movement of the lead screw and plays an anti-rotation role, thus realizing the left and right linear movement of the lead screw body without the need for an additional anti-rotation rod.

[0039] Nut 2 is positioned and supported by two tapered roller bearings 5, which can withstand large axial and radial forces. Furthermore, under more stringent installation requirements, the outer ring of the tapered roller bearing 5 can be integrally designed with the housing or cover, featuring a conical inner bore, making it a single component.

[0040] When the screw 3 extends linearly, sliding bushings 8 support both sides of the screw 3 to ensure smooth linear motion. The zipper-type dust cover 10 prevents dust from entering between the screw 3 and the bearing cap 6, ensuring an IP56 protection rating. In this example, the electric cylinder is driven by a permanent magnet synchronous motor 11 with a resolver, improving the control accuracy of the steering wheel.

[0041] In this example, the ball screw assembly has a gear-like outer ring portion, except for the internal raceway, and is a single-piece structure. In other embodiments, the ball screw nut 2 can also be a separate structure connected by threads.

[0042] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined by the scope of the claims.

Claims

1. A compact rotary electric cylinder characterized by, include Cylinder (1), both ends of which are provided with bearing caps (6); Nut (2), which is rotatably connected inside cylinder (1), and a transmission gear (13) is coaxially arranged on the outside of nut (2); The screw (3) passes through the cylinder (1) and the bearing cover (6) and is coaxially threaded with the nut (2). The screw (3) slides along the axial direction of the cylinder (1). A dust cover (10) is connected between the end of the screw (3) and the bearing cover (6). The dust cover (10) covers the screw (3). The motor (11) transmits power through a transmission assembly and a transmission gear (13) to drive the transmission gear (13) and the nut (2) to rotate.

2. The compact rotary electric cylinder according to claim 1, characterized by The nut (2) is rotatably mounted inside the cylinder (1) via a tapered roller bearing (5).

3. The compact rotary electric cylinder according to claim 1, characterized by A first adjusting shim (7) is provided between the bearing cap (6) and the cylinder (1).

4. The compact rotary electric cylinder according to claim 1, characterized by A sliding bushing (8) is provided between the screw (3) and the bearing cover (6).

5. The compact electric steering cylinder according to claim 1, characterized in that, A spiral raceway can be formed between the screw (3) and the nut (2), and balls are provided in the spiral raceway. The screw (3) and the nut (2) form a ball screw structure.

6. The compact rotary electric cylinder according to claim 1, characterized by The transmission assembly includes a motor (11) gear, a first gear (15) and a second gear (16). A housing (12) is connected to the cylinder (1). The motor (11) is connected to the housing (12). The motor (11) gear is coaxially connected to the output shaft of the motor (11). A transmission shaft (17) is provided inside the housing (12). The axial directions of the transmission shaft (17), the output shaft, and the nut (2) are all parallel to each other. The first gear (15) and the second gear (16) are coaxially arranged on the transmission shaft (17). The first gear (15) meshes with the motor (11) gear, and the second gear (16) meshes with the transmission gear (13).

7. The compact rotary electric cylinder according to claim 6, characterized by The output shaft is provided with a shaft end retaining ring (19).

8. The compact rotary electric cylinder according to claim 6, characterized by A deep groove ball bearing is provided between the drive shaft (17) and the housing (12), and a spacer (20) is provided between the end face of the deep groove ball bearing and the first gear (15) and the second gear (16).

9. The compact rotary electric cylinder according to claim 1, characterized by The motor (11) is a permanent magnet synchronous motor (11).

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