Starter speed reduction structure for improving return performance of isolator

Abstract

The utility model discloses a starter speed reduction structure capable of improving the return performance of an isolator, and belongs to the technical field of automobile starters. The clutch comprises a shell, a speed reducer, an isolator, a shifting fork and an electromagnetic switch, wherein the shifting fork consists of a shifting fork body made of a plastic material and a torsion spring; the torsion spring comprises symmetrical torsion springs on the two sides, the inner side supporting legs are connected to form a V-shaped force arm, and the outer side supporting legs extend linearly and are arranged in the arc-shaped containing groove of the shifting fork body; the shifting fork is rotationally connected with the shell through a fulcrum shaft, and the force arm is connected with a movable iron core of the electromagnetic switch. After the engine is started, the electromagnetic switch is powered off and reset, the shifting fork pushes the isolator to return under the action of elastic force of the torsional spring, mechanical accumulated force of the torsional spring can compensate the abrasion gap of the shifting fork, it is ensured that the isolator stably returns to the end face of the speed reducer, and the working reliability of the starter is improved.

Description

Technical Field

[0001] The utility model relates to the field of automobile starters, in particular to a starter deceleration structure capable of improving the return performance of a one-way device. Background Art

[0002] The starter is a core component of a vehicle's engine starting system. Its primary function is to use a motor to drive a one-way clutch to engage the engine's flywheel, thereby rotating the crankshaft and starting the engine. In existing technology, the starter's shift fork is typically an integrally injection-molded structure. Its operating principle is as follows: an electromagnetic switch, through the shift fork, drives the one-way clutch forward, causing it to engage with the flywheel and transmit power. After the engine starts, the electromagnetic switch resets, driving the shift fork back to its original position, which in turn pushes the one-way clutch away from the flywheel.

[0003] However, the existing structure has the following defects:

[0004] 1. The shift fork is an integrally molded plastic part. Its motion trajectory (such as the electromagnetic switch stroke, the middle fulcrum of the shift fork, and the position of the one-way device) must be accurately calculated. Long-term repeated rotation under force can easily lead to wear;

[0005] 2. After wear, the one-way device fails to return to its original position or even becomes loose, which affects the next starting performance of the starter;

[0006] 3. The accumulation of component tolerances can easily lead to an increase in fit clearance, further exacerbating the wear problem.

[0007] Therefore, there is an urgent need for a starter deceleration structure with optimized structure that can compensate for wear clearance to improve the return reliability of the one-way device. Utility Model Content

[0008] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide a starter deceleration structure that improves the return performance of the one-way device. By improving the fork structure and utilizing elastic force storage to compensate for the wear gap, the one-way device can be ensured to return stably and the starter's operating reliability can be improved.

[0009] To achieve the above-mentioned object, the present invention provides the following technical solution: a starter reduction structure for improving the return performance of a one-way device, comprising a housing, a reducer, a one-way device, a shift fork, and an electromagnetic switch; the reducer has a built-in planetary gear set that meshes with the gears on the motor output shaft; a spiral groove is formed on the output shaft of the reducer, the one-way device can be slidably mounted on the output shaft of the reducer, and the inner wall of the one-way device is in transmission engagement with the spiral groove; a limit ring is also provided on the output shaft of the reducer to prevent the one-way device from separating from the output shaft;

[0010] The shift fork is rotatably disposed within the housing, one end of which is connected to the end of the movable iron core of the electromagnetic switch, and the other end is a fork, which cooperates with the annular groove on the peripheral wall of the one-way device; the shift fork includes a shift fork body and a torsion spring; the shift fork body is made of plastic, and the torsion spring includes a torsion spring symmetrically arranged on both sides, the inner legs of the two torsion springs are connected to form a "V"-shaped force arm, and the two outer legs extend linearly in opposite directions of the force arm; the torsion spring is disposed within the shift fork body, and the force arm of the torsion spring extends out of the shift fork body and is transmission-connected to the end of the movable iron core of the electromagnetic switch;

[0011] The outer wall of the fork body is symmetrically provided with support shafts, and the fork is rotatably connected to the inner wall of the shell through the two support shafts; an arc-shaped receiving groove is provided between the two support shafts, and the torsion spring is placed in the receiving groove, and the force arm of the torsion spring extends from the receiving groove; the outer bottom of the receiving groove is arc-shaped, which facilitates the elastic deformation of the torsion spring when the fork swings.

[0012] Furthermore, the mating surface between the output shaft of the reducer and the spiral groove on the inner wall of the isolator is an involute tooth shape to reduce transmission friction resistance.

[0013] Furthermore, the limit ring is fixed to the end of the output shaft of the reducer by interference fit or threaded connection.

[0014] Furthermore, the fork opening of the fork body and the annular groove of the peripheral wall of the one-way device are clearance-matched, and the clearance is 0.1-0.3 mm, thereby ensuring the flexibility of the fork when pushing the one-way device.

[0015] Furthermore, the included angle of the "V"-shaped lever arm of the torsion spring is 30°-60° to balance the elastic force and the displacement.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] 1. Optimized shift fork structure: The traditional one-piece plastic shift fork has been improved to a composite structure of "body + torsion spring." Utilizing the mechanical force storage characteristics of the torsion spring, this effectively compensates for shift fork wear caused by long-term use, ensuring the one-way clutch returns to its original position.

[0018] 2. Improved return reliability: After the engine is started, the electromagnetic switch is powered off and reset. The shift fork continues to press the one-way clutch under the elastic force of the torsion spring. Even if the shift fork body has gaps due to wear, the torsion spring's torsion can still push the one-way clutch back to contact the reducer end face to prevent it from loosening.

[0019] 3. Enhanced structural stability: The curved bottom design of the accommodating groove optimizes the stress state of the torsion spring during fork swing, reducing fatigue loss of the torsion spring and extending its service life;

[0020] 4. Good assembly compatibility: The fork body is made of plastic and can be integrally formed through injection molding. It is easy to assemble with the torsion spring without the need for additional precision processing, thus reducing manufacturing costs.

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A cross-sectional view of a specific embodiment of the present utility model;

[0023] Figure 2 This is a cross-sectional view of a shift fork in a specific embodiment of the present utility model;

[0024] Figure 3 This is a front view of the fork body in a specific embodiment of the present invention;

[0025] Figure 4 This is a structural diagram of a torsion spring in a specific embodiment of the present invention.

[0026] Description of reference numerals:

[0027] 1-housing; 2-reducer; 21-planetary gear set; 22-output shaft; 221-spiral groove; 23-limiting retaining ring; 3-one-way device; 31-annular groove; 4-shift fork; 41-shift fork body; 411-support shaft; 412-accommodating groove; 42-torsion spring; 421-inner support leg; 422-outer support leg; 423-"V"-shaped force arm; 424-torsion spring; 5-electromagnetic switch; 51-moving iron core; 6-motor. DETAILED DESCRIPTION

[0028] The present invention is described in detail below through examples, which are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention.

[0029] like Figure 1 — Figure 4 As shown, this embodiment discloses a starter reduction gear structure for improving the return performance of a one-way device, including a housing 1, a reducer 2, a one-way device 3, a shift fork 4 and an electromagnetic switch 5.

[0030] The reducer 2 includes a planetary gear set 21, which meshes with the output gear on the output shaft of the motor 6 to reduce the motor's speed and increase its torque. The output shaft 22 of the reducer 2 is provided with a spiral groove 221. The one-way clutch 3 is slidably mounted on the output shaft 22, with its inner wall meshing with the spiral groove 221. (The spiral groove 221 meshes with the helical teeth on the inner wall of the one-way clutch 3, synchronizing the axial movement and rotation of the one-way clutch.) The end of the output shaft 22 is secured by a retaining ring 23 to prevent the one-way clutch 3 from disengaging from the output shaft.

[0031] The shift fork 4 is rotatably disposed in the housing 1, with one end driven by the moving iron core 51 of the electromagnetic switch 5, and the fork opening at the other end engages with the annular groove 31 on the peripheral wall of the isolator 3. Specifically, the shift fork 4 includes a shift fork body 41 made of plastic and a torsion spring 42:

[0032] Two support shafts 411 are symmetrically provided on the outer wall of the fork body 41, and are rotatably connected to the inner wall of the housing 1 through the support shafts 411; an arc-shaped receiving groove 412 is provided between the two support shafts 411 for accommodating the torsion spring 42;

[0033] The torsion spring 42 includes a bilaterally symmetrical torsion spring 424, the inner legs 421 of which are connected to form a "V"-shaped force arm 423 (with an angle of 35 degrees), and the outer legs 422 extend straight in opposite directions; the two torsion springs 424 of the torsion spring 42 are placed in the accommodating groove 412, the force arm 423 extends out of the fork body 41 and is connected to the end of the moving iron core 51 of the electromagnetic switch 5, and the outer legs 422 are inserted into the slot on the fork body 41 to limit the position.

[0034] How it works

[0035] 1. Startup phase: The electromagnetic switch 5 is energized, the moving iron core 51 moves toward the direction of the isolator 3, and the lever arm 423 of the torsion spring 42 pushes the fork body 41 to swing counterclockwise around the support shaft 411 (see Figure 2 In the direction of the arrow), the fork of the shift fork 4 pushes the one-way device 3 to move upward along the spiral groove 221 of the output shaft 22 until the one-way device 3 is engaged with the engine flywheel, and the motor 6 drives the flywheel to rotate through the planetary gear set 21 to start the engine.

[0036] 2. Return phase: After the engine is started, the electromagnetic switch 5 is de-energized, and the movable iron core 51 retracts under the action of the spring force, driving the lever arm 423 of the torsion spring 42 to move upward. At this time, the shift fork body 41 swings clockwise around the support shaft 411 under the elastic restoring force of the torsion spring 42, and the fork pulls the one-way device 3 downward along the spiral groove 221. Finally, the one-way device 3 contacts the end face of the reducer 2, completing the return phase.

[0037] 3. Wear compensation: If the fork body 41 wears out due to long-term use (for example, the clearance between the support shaft 411 and the housing 1 increases), the elastic force of the torsion spring 42 can continue to apply pressure to the one-way device 3, ensuring that the one-way device 3 returns to close contact with the end face of the reducer 2, avoiding the problem of incomplete return or looseness.

[0038] After adopting the above technical solution,

[0039] 1. Optimized shift fork structure: The traditional one-piece plastic shift fork has been improved to a composite structure of "body + torsion spring." Utilizing the mechanical force storage characteristics of the torsion spring, this effectively compensates for shift fork wear caused by long-term use, ensuring the one-way clutch returns to its original position.

[0040] 2. Improved return reliability: After the engine is started, the electromagnetic switch is powered off and reset. The shift fork continues to press the one-way clutch under the elastic force of the torsion spring. Even if the shift fork body has gaps due to wear, the torsion spring's torsion can still push the one-way clutch back to contact the reducer end face to prevent it from loosening.

[0041] 3. Enhanced structural stability: The curved bottom design of the accommodating groove optimizes the stress state of the torsion spring during fork swing, reducing fatigue loss of the torsion spring and extending its service life;

[0042] 4. Good assembly compatibility: The fork body is made of plastic and can be integrally formed through injection molding. It is easy to assemble with the torsion spring without the need for additional precision processing, thus reducing manufacturing costs.

Claims

1. A starter reduction gear structure for improving the return performance of a one-way device, comprising a housing (1), a reducer (2), a one-way device (3), a shift fork (4) and an electromagnetic switch (5); the reducer (2) has a built-in planetary gear set (21) that meshes with the gear on the output shaft of the motor (6) for transmission; a spiral groove (221) is provided on the output shaft (22) of the reducer (2); the one-way device (3) is slidably sleeved on the output shaft (22) and the inner wall of the one-way device (3) is in transmission engagement with the spiral groove (221); a limit retaining ring (23) is provided on the output shaft (22) of the reducer (2); the shift fork (4) is rotatably arranged in the housing (1), one end of which is connected to the end of the moving iron core (51) of the electromagnetic switch (5), and the other end is a fork that engages with the annular groove (31) on the peripheral wall of the one-way device (3); the characteristics are: The shift fork (4) includes a shift fork body (41) and a torsion spring (42); the torsion spring (42) includes a torsion spring symmetrically arranged on both sides, the inner legs (421) of the two torsion springs are connected to form a "V"-shaped force arm (423), and the two outer legs (422) extend straight in opposite directions toward the force arm (423); the torsion spring (42) is placed in the shift fork body (41), and the force arm (423) extends out of the shift fork body (41) and is connected to the electromagnetic switch (5). The end of the moving iron core (51) is connected in a transmission manner; support shafts (411) are symmetrically provided on the outer wall of the shift fork body (41), and the shift fork (4) is rotatably connected to the inner wall of the housing (1) through the two support shafts (411); an arc-shaped receiving groove (412) is provided between the two support shafts (411), the torsion spring (42) is placed in the receiving groove (412) and the force arm (423) extends from the receiving groove (412); the outer bottom of the receiving groove (412) is arc-shaped.

2. The starter deceleration structure for improving the return performance of the one-way device according to claim 1, characterized in that: The mating surfaces of the output shaft (22) of the reducer (2) and the spiral groove (221) on the inner wall of the isolator (3) are in an involute tooth shape.

3. The starter deceleration structure for improving the return performance of the one-way device according to claim 1, characterized in that: The limiting retaining ring (23) is fixed to the end of the output shaft (22) of the reducer (2) through interference fit or threaded connection.

4. The starter deceleration structure for improving the return performance of the isolator according to claim 1, characterized in that: The clearance between the fork opening of the fork body (41) and the annular groove (31) on the peripheral wall of the isolator (3) is 0.1-0.3 mm.

5. The starter speed reduction structure for improving the return performance of the isolator according to claim 1, characterized in that: The included angle of the "V"-shaped force arm (423) on the torsion spring (42) is 30°-60°.

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