Compact electric push rod

Abstract

The utility model belongs to the technical field of electric push rods, and particularly relates to a compact electric push rod. A compact type electric push rod comprises a reduction gearbox, a first gear and a second gear are arranged in the reduction gearbox, the first gear and the second gear are connected through a synchronous belt, the diameter of the first gear is smaller than that of the second gear, and a swing arm rotationally connected with a box body of the reduction gearbox is arranged on one side of the first gear. One end of the swing arm extends to one side of the middle of the synchronous belt, and a tensioning wheel making contact with the synchronous belt is arranged at one end of the swing arm. The other end of the swing arm extends to the side, deviating from the second gear, of the first gear, and the other end of the swing arm is connected with a compression spring. And the swing arm swings under the action of the compression spring, so that the tensioning wheel is in contact fit with the outer surface of the synchronous belt. The synchronous belt tensioning assembly has the advantage that the synchronous belt tensioning assembly can reasonably utilize the internal space of the reduction gearbox.

Description

Technical Field

[0001] The utility model belongs to the technical field of electric push rods, and in particular relates to a compact electric push rod. Background Art

[0002] The electric push rod is driven by a motor, and the motor and the lead screw are connected through a reduction gearbox. Usually, the reduction gearbox mainly achieves the deceleration effect through the meshing between the reduction gears. However, the transmission method between the reduction gears often causes the electric push rod to make a lot of noise when in use, affecting the use of the product. At present, the transmission between the gears is realized through a synchronous belt, thereby reducing the noise of the reduction gearbox.

[0003] In order to prevent the synchronous belt from loosening, a tensioning mechanism is usually set to squeeze the synchronous belt to ensure that the synchronous belt is in a tensioned state. For example, a Chinese patent with application number 202110795410.X discloses a baby stroller reducer assembly. The patent adjusts the position of the tensioning wheel by screwing a bolt so that the tensioning wheel presses the synchronous belt. However, the bolt screwing method may cause accidental touch and cannot adaptively tighten the synchronous belt.

[0004] Chinese patent application number 201811314028.7 discloses a power transmission device for an electric motorcycle, which pulls a swing arm by stretching a spring so that a belt tensioner can tighten a synchronous belt.

[0005] The above scheme adopts a tension spring to realize the swing of the swing arm. Although the synchronous belt can be adaptively tightened, there is an overlapping part between the tension spring and the synchronous belt in the axial direction of the above scheme. Therefore, in order to avoid contact between the tension spring and the synchronous belt, the axial distance between the synchronous belt and the reduction gear box body needs to be set larger, thereby increasing the axial length of the entire reduction gear box body; it is difficult to reasonably utilize the internal space of the reduction gear box. Utility Model Content

[0006] The utility model aims to provide a compact electric push rod which enables a synchronous belt tensioning component to reasonably utilize the inner space of a reduction box.

[0007] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a compact electric push rod, including a reduction box, wherein the reduction box is provided with a first gear for receiving the output torque of the motor and a second gear for rotating the screw rod, the first gear and the second gear are connected by a synchronous belt, the diameter of the first gear is smaller than the diameter of the second gear, one side of the first gear is provided with a swing arm rotatably connected to the housing of the reduction box, one end of the swing arm extends to one side of the middle part of the synchronous belt, and one end of the swing arm is provided with a tensioner contacting with the synchronous belt; the other end of the swing arm extends to a side of the first gear deviating from the second gear, and the other end of the swing arm is connected to a compression spring; the swing arm swings under the action of the compression spring so that the tensioner contacts and cooperates with the outer surface of the synchronous belt.

[0008] The first gear has a smaller diameter and fewer teeth than the second gear, thereby achieving a deceleration effect. Since the diameter of the first gear is small, there is more space between the first gear and the reduction gear box body, so the compression spring is set on the side of the first gear that deviates from the second gear, and the swing arm extends from the first gear side to the second gear side, thereby rationally utilizing the space in the electric push rod reduction gear box and making the structure more compact. Compared with the comparative document, this solution uses a compression spring to make the swing arm swing, so that the tensioning wheel applies pressure to the synchronous belt from the outside to the inside. There is no axial overlap between the compression spring and the synchronous belt, so there is no need to consider the axial spacing between the synchronous belt and the reduction gear box body, and there is no need to increase the axial length of the entire reduction gear box.

[0009] Preferably, the length of the power arm of the swing arm is smaller than the length of the resistance arm.

[0010] The length of the power arm of the swing arm is shorter than that of the resistance arm, thereby forming a labor-intensive lever, so that the rotation distance of one end of the power arm can be smaller, so that the compression spring can be set shorter, thereby rationally utilizing the space in the reduction box.

[0011] Preferably, a first sleeve and a second sleeve are respectively provided at both ends of the compression spring, the first sleeve is fixedly connected to the housing of the reduction gearbox, the second sleeve is fixedly connected to one end of the swing arm, and the first sleeve and the second sleeve are arranged on the outside of the compression spring.

[0012] The compression spring is guided and limited by the first sleeve and the second sleeve.

[0013] Preferably, both the first sleeve and the second sleeve are provided with positioning columns extending along their axial direction, and both ends of the compression spring are respectively sleeved on the outside of the positioning columns.

[0014] The expansion and contraction direction of the compression spring can be further guided and limited by the positioning column.

[0015] Preferably, the axial extension direction of the first sleeve is parallel to a side wall of the reduction gearbox, the swing arm comprises a power arm section, a rotation fulcrum and a resistance arm section, the thickness of the power arm section gradually decreases from the rotation fulcrum side to the end side of the power arm section to form an inclined surface, and the second sleeve is fixed on the inclined surface; when the compression spring applies force to the swing arm, the swing arm is tilted.

[0016] In order to reasonably utilize the space in the reduction box, the axial extension direction of the first sleeve is parallel to one side wall of the reduction box, so that the axial extension direction of the compression spring in the first sleeve is set to be parallel to one side wall of the reduction box. At the same time, an inclined surface is set on the power arm section, so that when the compression spring applies pressure to the power arm, the elastic force of the compression spring will be applied to the inclined surface, and the extension direction of the compression spring is parallel to one side wall of the reduction box, so the entire swing arm will be set at an angle (the reference object of the inclined setting is the reduction box body). Since the first gear and the second gear are different in size, the actual extension direction of the synchronous belt is also set at an angle, so the angle between the swing arm and the synchronous belt is smaller, so that the space in the reduction box body can be better utilized.

[0017] Preferably, reinforcing ribs are provided inside the swing arm.

[0018] In order to rationally utilize the space of the reduction gearbox, the swing arm will not be made thicker. Reinforcing ribs are set inside the swing arm to increase its strength.

[0019] The utility model has the advantage that the synchronous belt tensioning component can reasonably utilize the inner space of the reduction box. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure inside the reduction box of the utility model.

[0021] Figure 2 A side view of the swing arm.

[0022] Figure 3 This is an axonometric view of the swing arm.

[0023] Figure 4 It is a schematic diagram of the structure at the compression spring.

[0024] Figure numbers: 2, reduction box; 4, first gear; 41, second gear; 51, first sleeve; 52, second sleeve; 6, synchronous belt; 7, swing arm; 71, power arm section; 72, rotation fulcrum; 73, resistance arm section; 74, tensioner; 75, reinforcing rib; 8, compression spring; 9, positioning column. DETAILED DESCRIPTION

[0025] The utility model is further described below based on the accompanying drawings and specific embodiments.

[0026] like Figure 1 and Figure 2 As shown, this embodiment discloses a compact electric push rod, including a motor part (not shown in the figure), a reduction box 2 and a push rod part (not shown in the figure). The motor part is provided with a motor (not shown in the figure), the reduction box 2 is connected between the motor part 1 and the push rod part, and the push rod part is provided with a screw (not shown in the figure), a screw nut (not shown in the figure), a guide tube (not shown in the figure), and a jacking pipe and other components. The reduction box is provided with a first gear 4 for receiving the output torque of the motor and a second gear 41 for realizing the rotation of the screw. The diameter of the first gear 4 is smaller than the diameter of the second gear 41, and the number of teeth of the first gear 4 is less than the number of teeth of the second gear 41. The transmission between the first gear 4 and the second gear 41 is realized by a synchronous belt 6 with teeth.

[0027] like Figure 2 and Figure 4 As shown, a compression spring 8 is provided in the reduction box 2, and the compression spring 8 is arranged on the side of the first gear 4 that deviates from the second gear 41. A first sleeve 51 and a second sleeve 52 are respectively sleeved on both ends of the compression spring 8. The first sleeve 51 is fixedly connected to the housing of the reduction box 2 by screws, and a positioning column 9 extending along the axial direction thereof is provided inside the first sleeve 51 and the second sleeve 52, and both ends of the compression spring 8 are sleeved on the outside of the positioning column 9.

[0028] like Figures 2 to 4 As shown, the second sleeve 52 is connected to the swing arm 7, and the swing arm 7 is integrally arranged with the second sleeve 52. The swing arm 7 includes a power arm section 71, a rotation fulcrum 72 and a resistance arm section 73. The rotation fulcrum 72 is rotationally connected to the housing of the reduction box 2 through a rotating shaft. The end of the power arm section 71 of the swing arm 7 receives the elastic force of the compression spring 8, and the resistance arm section 73 is provided with a connection portion that is rotationally connected to the tensioner 74. The swing arm 7 swings around the rotation fulcrum 72 under the action of the compression spring 8, so that the tensioner 74 presses the outer surface of the synchronous belt 6. The entire swing arm 7 extends from the first gear 4 side to the second gear 41 side. The length of the power arm section 71 is less than the length of the resistance arm section 73, so that the power arm length of the entire swing arm 7 is less than the length of the resistance arm. The thickness of the power arm section 71 gradually decreases from the rotation fulcrum 72 side to the end side of the power arm section 71 to form an inclined surface, and the second sleeve 52 is fixed on the inclined surface. The axial direction of the first sleeve 51 is parallel to the upper side wall of the reduction box 2, and the swing arm 7 is tiltedly arranged in the reduction box 2. A reinforcing rib 75 is arranged inside the resistance arm section 73 of the swing arm 7.

Claims

1. A compact electric push rod, comprising a reduction box, wherein the reduction box is provided with a first gear for receiving the output torque of the motor and a second gear for rotating the screw rod, the first gear and the second gear are connected by a synchronous belt, the diameter of the first gear is smaller than the diameter of the second gear, and the characteristics are: A swing arm rotatably connected to the housing of the reduction gear box is provided on one side of the first gear, one end of the swing arm extends to one side of the middle of the synchronous belt, and one end of the swing arm is provided with a tensioner in contact with the synchronous belt; the other end of the swing arm extends to a side of the first gear that deviates from the second gear, and the other end of the swing arm is connected to a compression spring; the swing arm swings under the action of the compression spring to make the tensioner contact and cooperate with the outer surface of the synchronous belt.

2. The compact electric linear actuator according to claim 1, characterized in that: The length of the power arm of the swing arm is smaller than the length of the resistance arm.

3. The compact electric linear actuator according to claim 1, characterized in that: The two ends of the compression spring are respectively provided with a first sleeve and a second sleeve, the first sleeve is fixedly connected to the housing of the reduction box, the second sleeve is fixedly connected to one end of the swing arm, and the first sleeve and the second sleeve are arranged on the outside of the compression spring.

4. The compact electric linear actuator according to claim 3, characterized in that: The first sleeve and the second sleeve are both provided with positioning columns extending along their axial direction, and the two ends of the compression spring are respectively sleeved on the outside of the positioning columns.

5. The compact electric linear actuator according to claim 3, characterized in that: The axial extension direction of the first sleeve is parallel to a side wall of the reduction gearbox. The swing arm includes a power arm section, a rotation fulcrum and a resistance arm section. The thickness of the power arm section gradually decreases from the rotation fulcrum side to the end side of the power arm section to form an inclined surface. The second sleeve is fixed on the inclined surface. When the compression spring applies force to the swing arm, the swing arm is tilted.

6. The compact electric linear actuator according to any one of claims 1 to 5, characterized in that: A reinforcing rib is arranged inside the swing arm.

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