Adjustable drum brake structure of commercial vehicle axle

Abstract

The utility model provides a commercial vehicle axle adjustable drum brake structure which comprises a supporting roller, a brake bottom plate, a brake shaft, an S-shaped cam, a brake drum and a brake assembly, the brake bottom plate is fixed on the supporting roller, the brake shaft is rotatably connected to the brake bottom plate, the S-shaped cam is fixed on the brake shaft and located in the brake drum, and the brake assembly is fixed on the brake shaft and located in the brake drum. The brake assembly is arranged on the brake bottom plate, the S-shaped cam rotates and enables the brake assembly to abut against the inner wall of the brake drum, the end, away from the S-shaped cam, of the brake shaft is connected with a plurality of first positioning teeth, the first positioning teeth are evenly distributed along the axis of the brake shaft, the brake shaft is sleeved with and connected with an adjusting seat, and the adjusting seat is connected with a positioning ring. The inner wall of the positioning ring is fixedly connected with a plurality of second positioning teeth, the second positioning teeth are evenly distributed along the axis of the positioning ring, the first positioning teeth are meshed with the second positioning teeth, and the purpose of effectively compensating abrasion of the friction plate is achieved.

Description

Technical Field

[0001] This utility model relates to automobile axles, and more particularly to an adjustable drum brake structure for commercial vehicle axles. Background Technology

[0002] The braking system of commercial vehicles is a key assembly for ensuring driving safety. Among them, drum brakes are widely used due to their mature structure and large braking torque.

[0003] Currently, Chinese patent CN222479284U, by setting an offset section on the web plate, makes the web plate spacing at the end where the support pin is installed larger than the spacing at the end where the roller is installed. This allows the use of a support pin with a longer axial dimension without affecting the normal operation of the roller, and enables it to be interference-fitted with the pin hole on the brake backing plate. This enhances the support stiffness and stability of the brake shoes, effectively preventing brake shoe wobble, thus solving the problem of uneven wear of the friction pads and improving vehicle braking safety.

[0004] However, the safety issues arising from normal wear of the friction pads, such as increased brake clearance and longer pedal travel, remain a focus of ongoing attention and improvement in the drum brake industry. Effectively compensating for friction pad wear is another crucial issue for enhancing the safety of commercial vehicle braking systems. Utility Model Content

[0005] In view of this, the purpose of this utility model is to provide an adjustable drum brake structure for commercial vehicle axles, so as to effectively compensate for the wear of friction plates and improve safety.

[0006] To solve the above-mentioned technical problems, the technical solution of this utility model is: an adjustable drum brake structure for commercial vehicle axles, including a support roller, a brake base plate, a brake shaft, an S-shaped cam, a brake drum, and a brake assembly. The brake base plate is fixed on the support roller, the brake shaft is rotatably connected to the brake base plate, the S-shaped cam is fixed on the brake shaft and located inside the brake drum, the brake assembly is disposed on the brake base plate, the S-shaped cam rotates and abuts the brake assembly against the inner wall of the brake drum, the brake drum is rotatably connected to the support roller, a plurality of first positioning teeth are connected to the end of the brake shaft away from the S-shaped cam, the plurality of first positioning teeth are evenly distributed along the axis of the brake shaft, an adjusting seat is sleeved and connected to the brake shaft, a positioning ring is connected to the adjusting seat, a plurality of second positioning teeth are fixedly connected to the inner wall of the positioning ring, the plurality of second positioning teeth are evenly distributed along the axis of the positioning ring, the first positioning teeth mesh with the second positioning teeth, an adjusting plate is connected to the outer wall of the adjusting seat, the adjusting plate has a plurality of adjusting holes, the plurality of adjusting holes are arranged along the length direction of the adjusting plate.

[0007] To achieve the above technical solution, when the brake clearance increases due to normal wear of the friction pads, adjustment is required to restore optimal performance. At this time, maintenance personnel will operate through multiple adjustment holes on the adjustment plate. These adjustment holes provide positioning points for precise adjustment. By selecting the appropriate adjustment hole and connecting the air chamber to the corresponding adjustment hole, the operator can rotate the adjustment seat. The rotation of the adjustment seat will synchronously rotate the internal positioning ring. The second positioning tooth fixed on the inner wall of the positioning ring meshes tightly with the first positioning tooth at the end of the brake shaft, so the rotation of the adjustment seat will precisely drive the brake shaft to rotate at a small angle. This change in the brake shaft angle directly changes the initial position of the S-shaped cam. The change in the initial position of the S-shaped cam allows the brake assembly to extend further outward in the non-braking state, effectively compensating for the clearance caused by friction pad wear, ensuring that the brake always maintains the ideal brake clearance, thus avoiding the problem of excessive pedal travel and significantly improving the braking safety and stability of the vehicle.

[0008] As a preferred embodiment of this utility model, the end of the brake shaft is provided with an anti-disengagement groove, and a retaining spring is embedded in the anti-disengagement groove for abutting against the side wall of the adjusting seat.

[0009] To achieve the above technical solution, when the adjusting seat is fitted and connected to the brake shaft, the retaining ring embedded in the anti-disengagement groove of the brake shaft will abut against the side wall of the adjusting seat. This effectively prevents the adjusting seat from accidentally disengaging along the axial direction of the brake shaft while simultaneously adjusting the brake clearance.

[0010] In a preferred embodiment of this utility model, a positioning groove is provided on the inner wall of the adjusting seat, a slot is provided on the inner wall of the positioning groove, and a card plate is fixedly connected to the outer wall of the positioning ring. The positioning ring is embedded in the positioning groove and the card plate is embedded in the slot.

[0011] To achieve the above technical solution, during assembly, the positioning ring is embedded into the positioning groove of the adjusting seat, and simultaneously, the retaining plate on the positioning ring precisely engages with the retaining groove within the positioning groove. This achieves a stable connection and precise alignment between the positioning ring and the adjusting seat. The cooperation between the retaining plate and the retaining groove effectively prevents axial or radial relative movement of the positioning ring within the adjusting seat, ensuring that the first and second positioning teeth maintain the correct relative positions during engagement, thereby guaranteeing adjustment accuracy and post-adjustment stability. Furthermore, this embedded engagement method may simplify the assembly process and improve production efficiency.

[0012] As a preferred embodiment of this utility model, an extension plate is fixedly connected to the outer wall of the positioning ring, an extension groove is provided on the inner wall of the adjusting seat, the extension plate is placed in the extension groove, and a locking bolt is threadedly connected to the adjusting seat. The end of the locking bolt passes through the extension groove and abuts against the extension plate, thereby causing the locking plate to abut against the inner wall of the locking groove.

[0013] To achieve the above technical solution, when the positioning ring needs to be fixed, the end of the clamping bolt will abut against the extension plate. By tightening the clamping bolt, its force will press the clamping plate more tightly against the inner wall of the clamping groove. Thus, based on the fit between the clamping plate and the clamping groove, an additional preload is added. Through the threaded clamping action, any minor gaps or wobble that may exist between the clamping plate and the clamping groove can be eliminated. This greatly enhances the connection rigidity and stability of the positioning ring inside the adjusting seat, effectively preventing relative loosening or positional displacement of the adjusting seat and positioning ring due to vibration or impact during vehicle operation. This ensures the accuracy and durability of the brake clearance adjustment, further improving the safety and reliability of the commercial vehicle braking system.

[0014] In a preferred embodiment of this utility model, a support plate is fixedly connected to the support roller, the brake shaft is rotatably connected to the support plate, and the support plate is close to the adjustment seat.

[0015] The above technical solution ensures that the brake shaft has a stable support point when rotating, thus improving the rotational stability of the brake shaft.

[0016] As a preferred embodiment of this utility model, a mounting base for installing an air chamber is fixedly connected to the outer wall of the support roller. The mounting base has multiple mounting holes arranged along the length of the mounting base. The mounting holes and the adjustment holes are all located on the same side of the support roller. A connecting groove is provided on the mounting base.

[0017] To achieve the above technical solution, the air chamber is fixed to the mounting base through the mounting holes. Since multiple mounting holes are arranged along the length of the mounting base, the air chamber has more installation position options to ensure that the air chamber can be connected to the corresponding adjustment hole through the connecting groove. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the external structure of this utility model;

[0019] Figure 2 This is a schematic diagram illustrating the location of the brake components;

[0020] Figure 3 To illustrate the structure of the adjustment seat;

[0021] Figure 4 To illustrate the structure of the brake shaft;

[0022] Figure 5 This is a schematic diagram illustrating the structure of the positioning ring.

[0023] Reference numerals: 1. Support roller; 2. Brake base plate; 3. Brake shaft; 4. S-shaped cam; 5. Brake drum; 6. Brake assembly; 7. First positioning tooth; 8. Adjusting seat; 9. Positioning groove; 10. Slot; 11. Positioning ring; 12. Slot plate; 13. Second positioning tooth; 14. Extension plate; 15. Extension groove; 16. Anchor bolt; 17. Adjusting plate; 18. Adjusting hole; 19. Anti-detachment groove; 20. Snap ring; 21. Support plate; 22. Mounting seat; 23. Mounting hole; 24. Connecting groove. Detailed Implementation

[0024] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings, so that the technical solution of this utility model can be more easily understood and mastered.

[0025] An adjustable drum brake structure for a commercial vehicle axle includes a support roller 1, a brake base plate 2, a brake shaft 3, an S-shaped cam 4, a brake drum 5, and a brake assembly 6. The brake base plate 2 is fixed to the support roller 1 and located near its end.

[0026] The end of the brake shaft 3 is rotatably connected to the brake base plate 2, and the axis of the brake shaft 3 is parallel to the axis of the support roller 1. The brake assembly 6 is disposed on the brake base plate 2, and the brake drum 5 is rotatably connected to the support roller 1. The brake assembly 6 is located inside the brake drum 5.

[0027] The S-shaped cam 4 is fixed to the brake shaft 3 and located inside the brake drum 5. The S-shaped cam 4 rotates and causes the brake assembly 6 to press against the inner wall of the brake drum 5. The brake assembly 6 is prior art and will not be described in detail in this embodiment.

[0028] Multiple first positioning teeth 7 are connected to the end of the brake shaft 3 away from the S-shaped cam 4, and the multiple first positioning teeth 7 are evenly distributed along the axis of the brake shaft 3.

[0029] An adjusting seat 8 is sleeved and connected to the brake shaft 3. A positioning groove 9 is formed on the inner wall of the adjusting seat 8, and a retaining groove 10 is formed on the inner wall of the positioning groove 9. A retaining plate 12 is fixedly connected to the outer wall of the positioning ring 11. The positioning ring 11 is embedded in the positioning groove 9, and the retaining plate 12 is embedded in the retaining groove 10. A plurality of second positioning teeth 13 are fixedly connected to the inner wall of the positioning ring 11, and the plurality of second positioning teeth 13 are evenly distributed along the axis of the positioning ring 11. The first positioning tooth 7 is used to mesh with the second positioning tooth 13.

[0030] An extension plate 14 is fixedly connected to the outer wall of the positioning ring 11, and the length of the extension plate 14 is arranged radially along the positioning ring 11. An extension groove 15 is provided on the adjusting seat 8, and the extension plate 14 is placed in the extension groove 15. There is a gap between the inner wall of the extension groove 15 and the inner wall of the extension plate 14, that is, the length, width, and depth of the extension groove 15 are all greater than the length, width, and thickness of the extension plate 14. A locking bolt 16 is threadedly connected to the adjusting seat 8, and the end of the locking bolt 16 passes into the extension groove 15, so that the locking bolt 16 abuts against the extension plate 14, causing the extension plate 14 to tend to move towards the inner wall of the extension groove 15, and causing the clamping plate 12 to abut against the inner wall of the clamping groove 10.

[0031] An adjustment plate 17 is integrally connected to the outer wall of the adjustment seat 8. Three adjustment holes 18 are provided on the adjustment plate 17, and the three adjustment holes 18 are arranged along the length of the adjustment plate 17.

[0032] An anti-disengagement groove 19 is provided at the end of the brake shaft 3. The anti-disengagement groove 19 is annular and coaxially arranged with the brake shaft 3. A retaining spring 20 is embedded in the anti-disengagement groove 19 for abutting against the side wall of the adjusting seat 8.

[0033] A support plate 21 is fixedly connected to the outer wall of the support roller 1, and the brake shaft 3 is rotatably connected to the support plate 21. The support plate 21 is close to the adjusting seat 8.

[0034] A mounting base 22 for mounting the air chamber is fixedly connected to the outer wall of the support roller 1. The mounting base 22 is located on the upper surface of the support roller 1, and the brake shaft 3 is located on the lower surface of the support roller 1. Six mounting holes 23 are provided on the mounting base 22. Two mounting holes 23 form a group, and three groups of mounting holes 23 are arranged along the length of the mounting base 22. The mounting holes 23 and the adjusting hole 18 are all located on the same side of the support roller 1. A connecting groove 24 is provided on the mounting base 22, and the connecting groove 24 is located between two mounting holes 23 in the same group.

[0035] This patent application includes two main processes: braking and adjustment.

[0036] First, the normal braking process.

[0037] When the driver depresses the brake pedal, the air chamber drive converts the pressure of compressed air into mechanical force. This force acts on the brake shaft 3, causing it to rotate around its own axis. Since the S-shaped cam 4 is firmly fixed to the brake shaft 3, it rotates accordingly. The unique S-shaped profile of the S-shaped cam 4 expands outward during rotation, thereby pushing the brake assembly 6 mounted on the brake backing plate 2. Under the action of external force, the brake assembly 6 opens outward, causing its friction pads to press tightly against the inner wall of the brake drum 5, generating strong friction. This friction ultimately slows down the brake drum 5, which rotates with the wheel, thus achieving vehicle braking. When the brake is released, the S-shaped cam 4 returns to its original position, and the brake assembly 6 separates from the brake drum 5 under the action of the return spring, restoring the braking clearance.

[0038] Second, the braking clearance adjustment process.

[0039] With prolonged vehicle use and accumulated braking operations, the friction pads on the brake assembly 6 will experience normal wear. This wear causes the gap between the brake assembly 6 and the brake drum 5 to gradually increase, resulting in a longer brake pedal travel and affecting braking responsiveness and safety. To compensate for this wear and restore optimal braking performance, the following adjustment mechanism is provided:

[0040] I. Adjustment Preparation and Operation: Maintenance personnel will observe the braking performance. If they find that the brake clearance is too large or the pedal travel is too long, adjustment is required.

[0041] II. Air Chamber Drive and Initial Positioning: The air chamber is fixed to the mounting base 22 through the mounting holes 23. Since the six mounting holes 23 are arranged along the length of the mounting base 22, this provides more options for the air chamber's installation position. This flexibility ensures that the air chamber's actuator can be precisely mechanically connected to the corresponding adjustment hole 18 on the adjustment plate 17 through the communicating slot 24 on the mounting base 22.

[0042] III. Fine-tuning of the brake shaft: The adjusting seat 8 is sleeved and connected to the brake shaft 3. When the adjusting seat 8 rotates, the retaining plate 12 in the retaining groove 10 inside the positioning groove 9 on its inner wall will drive the positioning ring 11 to rotate accordingly. The multiple second positioning teeth 13 fixedly connected to the inner wall of the positioning ring 11 cause the brake shaft 3 to rotate due to the meshing of the first positioning teeth 7. Therefore, the rotation of the adjusting seat 8, through the precise meshing of the second positioning teeth 13 and the first positioning teeth 7, can drive the brake shaft 3 to undergo a slight angular rotation.

[0043] IV. Clearance Compensation and Locking: Because the actuator of the air chamber is connected to the adjustment holes 18 at different positions, the angle of the brake shaft 3 is slightly adjusted, directly changing the initial angle position of the S-shaped cam 4. This change in the initial position of the S-shaped cam 4 allows the brake assembly 6 to move closer to the brake drum 5 without applying brakes, effectively compensating for the additional clearance caused by friction pad wear. After adjustment, the threaded locking bolt 16 on the adjusting seat 8 is tightened, its end contacting the extension plate 14 fixedly connected to the outer wall of the positioning ring 11, further pressing the retaining plate 12 against the inner wall of the retaining groove 10, thus firmly locking the relative position between the positioning ring 11 and the adjusting seat 8. Simultaneously, the retaining spring 20 embedded in the annular anti-disengagement groove 19 at the end of the brake shaft 3 contacts the side wall of the adjusting seat 8, further preventing the adjusting seat 8 from accidentally disengaging along the axial direction of the brake shaft 3.

[0044] Of course, the above are just typical examples of this utility model. In addition, this utility model may have many other specific implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed by this utility model.

Claims

1. An adjustable drum brake structure for a commercial vehicle axle, comprising a support roller (1), a brake base plate (2), a brake shaft (3), an S-shaped cam (4), a brake drum (5), and a brake assembly (6), wherein the brake base plate (2) is fixed to the support roller (1), the brake shaft (3) is rotatably connected to the brake base plate (2), the S-shaped cam (4) is fixed to the brake shaft (3) and located inside the brake drum (5), the brake assembly (6) is disposed on the brake base plate (2), the S-shaped cam (4) rotates and abuts the brake assembly (6) against the inner wall of the brake drum (5), and the brake drum (5) is rotatably connected to the support roller (1), characterized in that: The brake shaft (3) is connected to a plurality of first positioning teeth (7) at the end away from the S-shaped cam (4). The plurality of first positioning teeth (7) are evenly distributed along the axis of the brake shaft (3). An adjusting seat (8) is sleeved and connected on the brake shaft (3). A positioning ring (11) is connected on the adjusting seat (8). A plurality of second positioning teeth (13) are fixedly connected to the inner wall of the positioning ring (11). The plurality of second positioning teeth (13) are evenly distributed along the axis of the positioning ring (11). The first positioning teeth (7) mesh with the second positioning teeth (13). An adjusting plate (17) is connected to the outer wall of the adjusting seat (8). A plurality of adjusting holes (18) are opened on the adjusting plate (17). The plurality of adjusting holes (18) are arranged along the length direction of the adjusting plate (17).

2. The adjustable drum brake structure for a commercial vehicle axle according to claim 1, characterized in that: The brake shaft (3) has an anti-disengagement groove (19) at its end, and a retaining ring (20) is embedded in the anti-disengagement groove (19) for contacting the side wall of the adjusting seat (8).

3. The adjustable drum brake structure for a commercial vehicle axle according to claim 1, characterized in that: The inner wall of the adjusting seat (8) is provided with a positioning groove (9), and the inner wall of the positioning groove (9) is provided with a slot (10). A card plate (12) is fixedly connected to the outer wall of the positioning ring (11). The positioning ring (11) is embedded in the positioning groove (9) and the card plate (12) is embedded in the slot (10).

4. The adjustable drum brake structure for a commercial vehicle axle according to claim 3, characterized in that: An extension plate (14) is fixedly connected to the outer wall of the positioning ring (11). An extension groove (15) is provided on the inner wall of the adjusting seat (8). The extension plate (14) is placed in the extension groove (15). A locking bolt (16) is threadedly connected to the adjusting seat (8). The end of the locking bolt (16) passes through the extension groove (15) and abuts against the extension plate (14), causing the clamping plate (12) to abut against the inner wall of the clamping groove (10).

5. The adjustable drum brake structure for a commercial vehicle axle according to claim 1, characterized in that: A support plate (21) is fixedly connected to the support roller (1), and the brake shaft (3) is rotatably connected to the support plate (21). The support plate (21) is close to the adjustment seat (8).

6. The adjustable drum brake structure for a commercial vehicle axle according to claim 1, characterized in that: A mounting base (22) for installing an air chamber is fixedly connected to the outer wall of the support roller (1). The mounting base (22) has multiple mounting holes (23) arranged along the length of the mounting base (22). The mounting holes (23) and the adjustment holes (18) are located on the same side of the support roller (1). The mounting base (22) has a connecting groove (24).

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