Automatic adjusting arm for automobile brake clearance

Abstract

The invention discloses an automobile brake clearance automatic adjusting arm which comprises a worm gear and a worm which are installed and meshed in a shell cavity, the shaft end of a right end shaft of the worm is pressed by a pressure spring and limited by an end cover, a shaft shoulder of a left end shaft of the worm is provided with a shaft shoulder conical tooth, and the shaft end of the left end shaft of the worm is provided with a blanking cap; a clutch sleeve arranged on a left end shaft of the worm in a sleeving mode is meshed with shaft shoulder conical teeth through right end face conical teeth, a one-way clutch bearing is arranged on the periphery of the clutch sleeve in a sleeving mode, a rotating sleeve is arranged on the periphery of the one-way clutch bearing in a static fit mode, a spiral groove is machined in the outer circumferential face of the rotating sleeve, and a pin penetrates through a pin hole in the shell and then is inserted into the spiral groove. The pin slides in the spiral groove to drive the rotating sleeve to rotate, and a plane bearing is installed on the left end face of the rotating sleeve. A limiting clamp spring is further fixedly arranged on a left end shaft of the worm, and a brake gap is guaranteed through an axial gap between the plane bearing and the limiting clamp spring. The structural form of the automobile brake clearance automatic adjusting arm is greatly simplified, and installation and maintenance are facilitated.

Description

Technical Field

[0001] This invention relates to automotive components, and more specifically to an automatic brake clearance adjustment device. Background Technology

[0002] A normal and reasonable minimum clearance, known as "brake clearance," needs to be maintained between the brake pads and the brake drum in a vehicle's service brake system to ensure optimal braking performance. However, the brake clearance gradually increases due to brake use and pad wear, causing the clearance between the four wheels to become uneven. This can lead to braking lag, vehicle pulling to one side, excessive braking distance, and other safety hazards, potentially causing traffic accidents. Therefore, it is essential to adjust the position of the brake pads promptly to maintain the proper clearance between them and the brake drum.

[0003] The invention patent announcement CN101526116B discloses an automatic adjustment arm for automobiles, comprising a housing, a control arm, a large worm gear, and a large worm. A gear ring is fixedly connected to the control arm. The housing contains a one-way clutch mechanism connected to the large worm and a control mechanism for controlling the engagement and disengagement of the clutch mechanism. The control mechanism includes a gear connected to the housing and meshing with the gear ring, and a small worm connected to the one-way clutch mechanism. The small worm is axially slidably connected to the housing, and the gear is circumferentially fixed and axially slidably connected to the small worm. The housing has a limiting member that restricts and adjusts the sliding stroke of the small worm. The small worm has a return spring that, when there is no braking, allows the small worm to reset and maintain a set gap with the limiting member. This automatic adjustment arm can automatically adjust the brake clearance between the brake drum and the brake shoes, and the automatic clearance setting range can be adjusted. In use, the control arm is fixed to the axle, the housing of the adjustment arm can rotate around the control arm, the large worm gear is connected to the braking mechanism, and the housing is connected to the brake pedal mechanism. The invention patent announcement text with announcement number CN213808594U discloses an automatic adjustment arm for automobiles, which solves the problem of low adjustment accuracy in existing automatic adjustment arms. This automatic adjustment arm includes a housing, within which a large worm gear and a large worm cooperating with the worm gear are installed. One end of the large worm gear has a spring seat, a spring, and a screw cap in sequence, while the other end of the large worm gear has bevel teeth that mesh with a small worm gear under the elastic force of the spring. A small worm gear meshing with the small worm gear is also installed inside the housing. An anti-rotation structure to increase the friction coefficient between the end of the large worm gear and the spring seat is provided. The existing technologies described above share the problems of complex structure, inconvenient installation, and high cost. Furthermore, the above structure requires a control arm, which drives a ratchet clutch via a transmission gear to record the increased clearance due to wear of the shoe plates. The control arm needs to be fixedly connected to the automobile chassis via a connector.

[0004] Currently, the brake clearance adjustment mechanisms used in various types of trucks, trailers, and buses also suffer from problems such as complex structure, high cost, and cumbersome installation process. Furthermore, existing products, when the automatic adjustment function fails, cannot effectively lock the manually adjusted brake clearance, causing it to revert and widen, which seriously affects driving safety and ease of use. Summary of the Invention

[0005] The present invention aims to overcome the shortcomings of the prior art by providing an automatic brake clearance adjustment arm for automobiles, which optimizes the structure, reduces costs, and simplifies installation while ensuring driving safety.

[0006] The present invention adopts the following technical solution to solve the technical problem; The automatic brake clearance adjustment arm of the present invention includes: a worm gear installed in a cavity formed by a housing and a cover plate, a worm engaging with the worm gear for transmission, a friction-reducing pad installed at the right end of the worm shaft, the friction-reducing pad being pressed against by a compression spring on the right side and limited by the right end cover, with the right end cover serving as the spring seat of the compression spring.

[0007] The automatic brake clearance adjusting arm of this invention is characterized by: a shoulder bevel tooth on the shoulder of the left end shaft of the worm gear, and a plug at the end of the left end shaft of the worm gear; a clutch sleeve fitted on the left end shaft of the worm gear engages with the shoulder bevel tooth with its right end face bevel tooth for transmission; a one-way clutch bearing is fitted on the outer circumference of the clutch sleeve, the one-way clutch bearing being a one-way dynamic fit component; a rotating sleeve is statically fitted on the outer circumference of the one-way clutch bearing; a spiral groove is machined on the outer circumferential surface of the rotating sleeve, and a pin passes through the pin hole on the housing and is inserted into the spiral groove, using the sliding of the pin in the spiral groove to form a rotational drive for the rotating sleeve; a plane bearing is installed on the left end face of the rotating sleeve; a limit snap ring is also fixedly installed on the left end shaft of the worm gear, and the axial clearance between the plane bearing and the limit snap ring ensures the brake clearance.

[0008] The automatic brake clearance adjusting arm of the present invention is also characterized in that: the plug has a tail end plate and an annular sleeve fixedly connected to the tail end plate, the right end face of the annular sleeve can fit against the left end face of the planar bearing; an annular groove is provided on the inner side wall of the annular sleeve, and a limiting snap ring protruding from the surface of the worm gear is located in the annular groove.

[0009] The manual brake clearance adjusting arm of this invention is also characterized by: a bolt being provided on the tail end plate of the plug, and a "U"-shaped retaining plate being fixed by the bolt. The "U"-shaped retaining plate is locked in two different positions by the bolt. In position one, the "U"-shaped groove of the "U"-shaped retaining plate is locked onto the hexagonal head at the left end of the worm gear. In position two, the "U"-shaped retaining plate is released from locking onto the hexagonal head at the left end of the worm gear, thus releasing the lock.

[0010] Compared with existing technologies, the beneficial effects of this invention are reflected in: 1. Compared with existing technologies, the structure of this invention is greatly optimized. It eliminates the need for a control arm, removes the transmission gear that works with the control arm, and eliminates the ratchet clutch driven by the transmission gear. The simplification of the overall structure leads to a significant reduction in cost and greatly simplifies the installation process.

[0011] 2. This invention uses a one-way clutch bearing to achieve automatic adjustment, which allows for a more precise adjustment range and timely and accurate adjustment process, effectively ensuring driving safety.

[0012] 3. The present invention provides an annular groove on the inner wall of the plug annular sleeve, and the limiting spring can move axially in the annular groove. The axial length of the annular groove effectively ensures the "braking gap" during normal driving.

[0013] 4. The invention includes a U-shaped retaining plate. When the automatic adjustment function fails, the retaining plate is used to fix the worm shaft, effectively preventing it from retracting on its own and causing the braking clearance to increase, thereby ensuring driving safety. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the present invention.

[0015] Figure 2 This is a partial enlarged view of the left end shaft of the worm gear in this invention.

[0016] Figure 3 for Figure 1 Enlarged view of the left end face.

[0017] The following components are labeled in the diagram: 1. Housing, 2. Anti-friction pad, 3. Compression spring, 4. Spring seat, 5. Worm gear, 6. Cover plate, 7. Worm, 8. Shoulder bevel gear, 9. One-way clutch bearing, 10. Clutch sleeve, 11. Rotary sleeve, 12. Planar bearing, 13. Snap ring, 14. Snap plate, 15. Bolt, 16. Plug, 16a. Tail end plate, 16b. Annular sleeve, 16c. Annular groove, 17. Pin, 18. Spiral groove, 19. Left hexagonal head, 20. Camshaft. Detailed Implementation

[0018] See Figure 1 In this embodiment, the automatic brake clearance adjustment arm includes: a worm gear 5 installed in the cavity formed by the housing 1 and the cover plate 6; a worm 7 meshing with the worm gear 5 for transmission; a friction-reducing pad 2 installed at the right end of the worm 7 shaft; the friction-reducing pad 2 being pressed against the right side by a compression spring 3 and limited by the right end cover 4; the right end cover 4 serving as the spring seat of the compression spring 3; and the release of the stored force of the compression spring 3 pushing the worm shaft back to its original position.

[0019] See Figure 1 , Figure 2 and Figure 3 In this embodiment, the automatic brake clearance adjusting arm of the automobile has a shoulder bevel tooth 8 on the shoulder of the left end shaft of the worm 7, and a plug 16 is provided at the end of the left end shaft of the worm 7; the clutch sleeve 10, which is fitted on the left end shaft of the worm, engages with the shoulder bevel tooth 8 through its right end face bevel tooth for transmission; a one-way clutch bearing 9 is fitted on the outer periphery of the clutch sleeve 10. The one-way clutch bearing 9 is a one-way moving fit component, which means that the one-way bearing 9 and the clutch sleeve 10 are in a one-way moving fit, that is, they rotate freely in the forward direction and engage in the reverse direction for transmission. A rotating sleeve 11 is statically fitted with a spiral groove 18 machined on the outer circumferential surface of the rotating sleeve 11. A pin 17 passes through the pin hole on the housing 1 and is inserted into the spiral groove 18. The relative sliding of the pin 17 in the spiral groove 18 forms a rotational drive for the rotating sleeve 11. A plane bearing 12 is installed on the left end face of the rotating sleeve 11 to ensure smooth operation and reduce wear. A limit snap ring 13 is also fixedly installed on the left end shaft of the worm gear 7 to ensure the braking clearance by the axial clearance between the plane bearing 12 and the limit snap ring 13.

[0020] The corresponding structural settings in the specific implementation also include: Figure 1 and Figure 2 As shown, in this embodiment, the plug 16 has a tail end plate 16a and an annular sleeve 16b fixedly connected to the tail end plate. The right end face of the annular sleeve 16b can fit against the left end face of the planar bearing. An annular groove 16c is provided on the inner side wall of the annular sleeve 16b. The limiting snap ring 13 protruding from the surface of the worm 7 is located in the annular groove 16c. When the worm shaft is pushed back due to the release of the stored force of the compression spring 3, the snap ring 13 returns to the left end of the annular groove 16c. When the wear clearance of the shoe increases and the distance of the worm 7 moving to the right increases, the snap ring 13 abuts against the left end face of the planar bearing 12 and moves to the right together with the worm shaft, pulling the planar bearing 12, the rotating sleeve 11, the one-way clutch bearing 9 and the clutch sleeve 10.

[0021] Figure 1 and Figure 3 As shown, a bolt 15 is provided on the tail end plate of the plug 16, and a "U"-shaped clamping plate 14 is fixed by the bolt 15. The "U"-shaped clamping plate 14 is locked in two different positions by the bolt 15. The first position is that the "U"-shaped groove of the "U"-shaped clamping plate 14 is locked to the left hexagonal head 19 of the worm 7, thereby locking the worm 7. The second position is that the "U"-shaped clamping plate 14 is released from the lock on the left hexagonal head 19 of the worm 7, thus releasing the lock.

[0022] In practice, the camshaft 20 and the worm gear 5 are fixedly connected by a spline. During normal braking, the adjusting arm drives the camshaft 20 to rotate. The rotation of the camshaft 20 achieves braking by jacking up the brake shoes and rubbing them against the brake drum. At the same time, the worm 7 compresses the compression spring 3 and moves a distance to the right along the axial direction. The bevel teeth 8 on the worm 7 separate from the bevel teeth on the clutch sleeve 10. The retaining spring 13 moves to the right end of the groove along with the worm shaft and abuts against the end face of the plane bearing. The axial distance of separation is the braking clearance during normal driving. When the brake is released, the stored force of the compression spring 3 is released, pushing the worm shaft back to its initial position. The retaining spring 13 also returns to the left end of the groove.

[0023] When the shoe wear clearance increases and braking occurs, the worm 7 moves a greater distance to the right. Due to the action of the retaining ring 13, the worm shaft continues to move to the right, pulling the plane bearing 12, the rotating sleeve 11, the one-way clutch bearing 9, and the clutch sleeve 10 to move to the right together. During the movement, due to the limitation of the pin 17 in the spiral groove 18, the rotating sleeve 11 drives the one-way bearing 9 to rotate at a certain angle on the outer circumference of the clutch sleeve 10. The adjusting arm is in the pre-adjustment state, completing the recording of shoe wear.

[0024] When the brake is released, the worm 7 begins to return to the left. When it returns to the normal clearance, the shoulder bevel tooth 8 on the left side of the worm 7 engages with the clutch sleeve 10. The rotating sleeve 11, under the action of the pin 17, drives the one-way clutch bearing 9 to grip the clutch sleeve 10, and through the shoulder bevel tooth 8, drives the worm 7 and worm wheel 5 to rotate by an angle, causing the camshaft 20 to rotate by a corresponding angle, thereby bringing the shoe closer to the brake drum, thus reducing the increased shoe clearance and achieving the purpose of automatic adjustment.

[0025] When the adjusting arm is set to automatic adjustment mode, the "U"-shaped clamp 14 disengages from the hexagonal head 19 at the left end of the worm shaft; when the automatic adjustment function fails, the "U"-shaped clamp 14 is used to fix the worm shaft to prevent it from retracting on its own and causing the brake clearance to increase, thus ensuring driving safety and realizing manual-automatic integration. It can be widely used in various types of trucks, trailers and buses.

Claims

1. An automotive brake lash self-adjusting arm comprising: The worm (5) is installed in the cavity formed by the shell (1) and the cover plate (6), the worm gear (7) is in meshing transmission with the worm (5), the wear pad (2) is installed on the right end of the shaft of the worm gear (7), the wear pad (2) is pressed by the compression spring (3) on the right side and is limited by the right end cover (4); characterized in that: the shaft shoulder bevel gear (8) is arranged on the left end of the shaft of the worm gear (7), the plug cover (16) is arranged on the left end of the shaft of the worm gear (7); the clutch sleeve (10) sleeved on the left end of the shaft of the worm gear is in meshing transmission with the shaft shoulder bevel gear (8) through the right end face bevel gear, the one-way clutch bearing (9) is sleeved on the outer periphery of the clutch sleeve (10), the one-way clutch bearing (9) is a one-way dynamic fitting component, the rotating sleeve (11) is assembled on the outer periphery of the one-way clutch bearing (9) in static fit, the helical groove (18) is processed on the outer circumferential surface of the rotating sleeve (11), the pin (17) is inserted into the helical groove (18) through the pin hole on the shell (1), the rotation of the rotating sleeve (11) is driven by the sliding of the pin (17) in the helical groove (18), the plane bearing (12) is installed on the left end surface of the rotating sleeve (11); the limit snap spring (13) is also fixedly arranged on the left end of the shaft of the worm gear (7), and the axial gap between the plane bearing (12) and the limit snap spring (13) ensures the brake gap.

2. The automotive brake lash self-adjusting arm of claim 1 wherein: The plug cover (16) has a tail end plate (16a) and an annular sleeve (16b) fixedly connected with the tail end plate (16a), the right end surface of the annular sleeve (16b) can be attached to the left end surface of the plane bearing; the annular groove (16c) is arranged on the inner side wall of the annular sleeve (16b), and the limit snap spring (13) protruding from the surface of the worm gear (7) is located in the annular groove (16c).

3. The automotive brake lash manual adjustment arm of claim 1 wherein: The bolt (15) is arranged on the tail end plate of the plug cover (16), the "U"-shaped clamping plate (14) is fixedly arranged by the bolt (15), the "U"-shaped clamping plate (14) is locked in two different positions by the bolt (15), position one is that the "U"-shaped groove of the "U"-shaped clamping plate (14) is clamped on the left end hexagonal head of the worm gear (7), and the worm gear (7) is locked; position two is that the "U"-shaped clamping plate (14) is separated from the clamping of the left end hexagonal head (19) of the worm gear (7), and the locking is released.

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