Novel hub brake structure

Abstract

The utility model relates to the technical field of brake systems, and discloses a novel hub brake structure which comprises a brake box assembly, a brake shoe assembly, a cam shaft and a rocker arm, the brake shoe assembly is arranged on the inner side of the brake box assembly, and the first end of the brake shoe assembly is in pivot connection around a fixed core rotating shaft in the brake box assembly. The second end of the brake shoe assembly and a cam shaft rotationally arranged in a cam shaft hole of the brake box assembly are arranged in a clamped mode, the second end is of a cylindrical structure and abuts against a cam part of the cam shaft in a rolling mode, and the section of the cam part is of a smooth transition curve structure composed of an initial abutting area, a buffer area and a brake working area which are symmetrically arranged. When the cam shaft rotates to the buffer area and abuts against the second end, the brake shoe assembly is in the wear limit position. The problems that an existing brake shoe is in plane contact with a cam shaft, a brake dead point exists, clamping stagnation and jamming are prone to occurring, brake failure is caused, and then safe driving is affected are solved.

Description

Technical Field

[0001] This utility model relates to the technical field of braking systems, specifically to a novel drum brake structure. Background Technology

[0002] Drum brakes have been used as braking components on motorcycles and electric vehicles for nearly a century. Their structure generally involves pushing the brake friction shoe assembly inside the brake drum outward, causing the brake friction shoes to rub against the brake drum as the wheel rotates, thus slowing down or stopping the wheel.

[0003] In existing hub brakes, the rocker arm drives the camshaft to move the left and right brake shoes to open and close the brake. The camshaft and brake shoes are in planar contact, and sliding friction is generated between them during operation. This structural design has low mechanical efficiency, generates large frictional resistance, slow braking process, and excessive braking stroke, which poses a safety hazard.

[0004] In existing technologies, the contact surface between the brake pads and the camshaft is a single plane, resulting in sliding friction during operation and a low force transmission ratio. For example, CN110541896A describes a dynamic braking balance hub brake for vehicles. This brake has high actuation resistance and poor braking feel, and the cam and brake pad inserts are prone to wear. Furthermore, since the two ends or one end of the camshaft are usually at the position of maximum rotation radius, there is a braking dead point at one or both ends of the camshaft. After the brake pads have been used for a period of time, the braking free travel of the braking device will increase significantly. Continuing to move the cam until the two ends abut against the brake pads can easily cause jamming or seizing, leading to brake failure and affecting safe driving. Utility Model Content

[0005] To address the shortcomings of existing technologies, this application provides a novel hub brake structure that solves the problems of existing brake pads and camshafts having planar contact and sliding friction, resulting in low transmission efficiency, high control resistance, and brake pad wear, jamming, and brake failure due to the presence of a braking dead point at the end of the camshaft, thus affecting safe driving.

[0006] To achieve the above objectives, this application adopts the following technical solution.

[0007] This utility model is a novel hub brake structure, including a brake box assembly, a brake shoe assembly, a camshaft, and a rocker arm. The brake shoe assembly is provided inside the brake box assembly. The first end of the brake shoe assembly is pivotally connected around a centering shaft inside the brake box assembly. The second end of the brake shoe assembly is clamped to a camshaft that is rotatably disposed in the camshaft hole of the brake box assembly. The second end is a cylindrical structure that rolls against the cam portion of the camshaft. The cross-section of the cam portion is a smooth transition curve structure composed of a symmetrically arranged initial contact area, a buffer zone, and a braking working area. When the camshaft rotates to the transition position between the braking working area and the buffer zone, the brake shoe assembly is at its wear limit position.

[0008] Further improvements include: the initial contact area is set as a concave arc structure, the two buffer zones are set as concentric circular arc structures, the braking working area is set as an involute structure, and the cam section is formed by the interconnection of symmetrically arranged concave arc structures, involute structures, and circular arc structures to form a "gourd" shaped structure.

[0009] Further improvements include: the maximum braking radius of the braking working area is not less than the radius of the buffer zone; the buffer zone and the braking working area transition smoothly; and the braking working area and the initial contact area are connected by an arc-shaped structure to the working transition area.

[0010] A further improvement is that the camshaft also includes a pivoting part and a connecting part coaxially disposed at the lower end of the cam section. The pivoting part is pivotally installed in the camshaft hole, and the connecting part has a connecting structure adapted to the rocker arm on its outer side.

[0011] A further improvement is that the connecting structure is set as a toothed, splined, or polygonal structure, and the connecting part is also provided with a limiting groove.

[0012] A further improvement is that a cam seat is provided between the cam part and the pivot part, the cam seat is designed as a flat round structure, and the pivot part is also provided with an annular groove.

[0013] A further improvement is that the second end is also provided with a rolling mechanism, which is pivotally connected to the second end by a cylindrical roller structure and is rotatably connected. The cylindrical roller structure is in rolling clamping contact with the cam part.

[0014] A further improvement is that: a through hole is provided at the second end, and a connecting groove is also provided at the second end. The connecting groove divides the second end into upper and lower parts along the center layer of the second end. The cylindrical roller structure is composed of a cylindrical roller, a pin, and a retaining ring. The cylindrical roller is rotatably connected to the second end through the pin and the retaining ring. The outer diameter of the cylindrical roller is larger than that of the second end and contacts the cam part.

[0015] A further improvement is that: the top of the second end and the outside of the through hole are provided with a limiting protrusion and a groove, and the pin head end and the limiting protrusion are provided with a matching anti-rotation surface.

[0016] Further improvements include: a friction material is provided on the outer side of the brake shoe assembly, and multiple noise reduction and heat dissipation structures are provided on the friction material; the rocker arm is located on the outer side of the brake box housing assembly and is detachably connected to one end of the camshaft; rotating the rocker arm drives the camshaft to move the brake shoe assembly around the fixed core shaft to achieve opening and closing actions.

[0017] Compared with the prior art, the advantages of this utility model are:

[0018] By setting a cylindrical arc surface at the second end of the brake shoe assembly to roll against the cam portion of the camshaft, the existing surface contact between the brake shoe assembly and the camshaft is changed to rolling contact, transforming sliding friction into rolling friction, reducing the braking friction resistance between the two, thereby improving the braking mechanical efficiency of the brake assembly; while ensuring the brake stroke remains unchanged, the output force transmission ratio of the camshaft is increased through the involute curved surface design, thereby reducing the braking resistance, improving the lightness and comfort of the braking feel, and thus improving the problem of heavy braking feel; at the same time, since the surface contact between the brake shoe assembly and the camshaft is rolling contact, the wear between the camshaft and the end of the brake shoe is reduced, extending the overall service life of the hub brake;

[0019] By setting a cam section with a smooth transition curve structure consisting of a symmetrical initial contact area, a braking working area, and a buffer zone on the camshaft, and rolling contact with the second end, when the camshaft rotates to contact the buffer zones at both ends and the second end, since the braking working area and the buffer zone are smoothly transitioned and the maximum braking radius of the braking working area is not less than the radius of the buffer zone, there is no braking dead point. Therefore, there will be no brake failure due to the braking dead point, which will affect safe driving.

[0020] Meanwhile, when the camshaft rotates to the transition position between the braking working area and the buffer zone, the brake shoe assembly is at its wear limit position. That is, after the brake shoes are opened to their maximum limit position, turning to the buffer zone will only result in an insignificant braking effect. There is no need to add an additional wear indicator structure to accurately indicate that the brake shoe assembly needs to be replaced, thus ensuring safe driving needs.

[0021] Since the maximum braking radius of the braking working area is the maximum braking distance of the entire camshaft, the braking working area is designed as an involute structure to meet the requirement that the braking distance gradually increases from small to large, so as to satisfy the requirement that the brake shoe assembly gradually expands to the maximum and reaches the wear limit. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0023] Figure 2 This is an exploded view of the present invention;

[0024] Figure 3 This is a perspective view of the camshaft of this utility model;

[0025] Figure 4 This is a utility model Figure 3 Top view;

[0026] Figure 5 This is a three-dimensional schematic diagram of one side of the brake shoe of this utility model;

[0027] Figure 6 This is an exploded view of the rolling mechanism of the brake shoe on one side of this utility model;

[0028] Figure 7 This is a schematic diagram of the working position of the camshaft of this utility model.

[0029] Attached image labels:

[0030] Brake box assembly-1, central shaft hole-11, center pivot shaft-12, camshaft hole-13, brake shoe assembly-2, first end-21, second end-22, through hole-221, connecting groove-222, position protrusion-223, groove-224, rolling mechanism-23, cylindrical roller-231, pin-232, snap ring-233, friction material-24, noise reduction and heat dissipation structure-25, camshaft-3, cam part-31, initial contact area-311, braking working area-312, buffer area-313, pivot part-32, connecting part-33, limiting groove-34, cam seat-35, annular groove-36, rocker arm-4. Detailed Implementation

[0031] To enhance understanding of this utility model, it will be further described in detail below with reference to the accompanying drawings. This embodiment is only used to explain this utility model and does not constitute a limitation on the scope of protection of this utility model.

[0032] In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the combination or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0034] like Figure 1-5The diagram shows a novel hub brake structure, comprising a brake box assembly 1, a brake shoe assembly 2, a camshaft 3, and a rocker arm 4. The brake box assembly 1 has a central shaft hole 11 at its center, with a centering shaft 12 and a camshaft hole 13 symmetrically arranged on either side of the central shaft hole 11. The brake shoe assembly 2 is installed inside the brake box assembly 1. The first end 21 of the brake shoe assembly 2 is an arc-shaped structure pivotally connected around the centering shaft 12. The second end 22 of the brake shoe assembly 2 is clamped to one end of the camshaft 3, which is rotatably disposed in the camshaft hole 13 of the brake box assembly 1. The rocker arm 4 is connected to the outside of the brake box assembly 1 via the other end of the camshaft 3. The left and right brake shoes of component 2 are respectively provided with return springs to give the brake shoe assembly a return driving force. The second end 22 is set as a cylindrical structure and rolls against the cam part 31 of the cam shaft 3. The cross section of the cam part 31 is a smooth transition curve structure composed of the symmetrically arranged initial contact area 311, buffer zone 313 and brake working area 312 connecting the initial contact area 311 and buffer zone 313. When the cam shaft 3 rotates to the transition position between the brake working area (312) and the buffer zone (313) and abuts against the second end 22, the brake shoe assembly 2 is at the wear limit position, that is, the maximum limit position of the brake shoe assembly 2.

[0035] By providing a cylindrical arc surface at the second end 22 of the brake shoe assembly to roll against the cam portion 31 of the camshaft 3, the surface contact between the existing brake shoe assembly and the camshaft is changed to rolling contact, reducing the initial braking friction between the two, thereby reducing braking resistance and improving the braking mechanical efficiency of the brake assembly. Furthermore, by shortening the lever arm relative to the rotation center of the camshaft 3 at the point where the cylindrical arc surface at the second end 22 rolls against the cam portion 31, the transmission ratio of the camshaft 3 is increased, improving the lightness and comfort of the braking feel, thus alleviating the problem of heavy braking. Since the surface contact between the brake shoe assembly and the camshaft is rolling contact, wear between the camshaft and the brake shoe end is reduced. This extends the overall service life of the hub brake. By setting a cam portion 31 with a smooth transition curve structure consisting of a symmetrical initial contact area 311, a braking working area 312, and a buffer zone 313 on the camshaft 3, and rolling contact with the second end, the camshaft 3 rotates to the buffer zones 313 at both ends. Since the braking working area 312 and the buffer zone 313 are smoothly transitioned and there is no braking dead point, only the braking effect will be less obvious, and there will be no brake failure due to jamming or sticking caused by the braking dead point, which will affect safe driving. At the same time, when the camshaft 3 rotates to the buffer zone 313, only the braking effect will be less obvious. There is no need to add a wear indicator structure to accurately indicate that the brake pad assembly needs to be replaced, ensuring the needs of safe driving.

[0036] An alternative implementation, such as Figure 3 , 4As shown: the initial contact area 311 is set as a concave arc structure, the two concave arc radii are set as R1, the two buffer zones 313 are set as concentric circular arc structures, the braking working area 312 is set as an involute structure, and the cam part 31 cross section is formed by symmetrically arranged concave arc structures, involute structures and circular arc structures connected to each other to form a "gourd" shaped structure; the buffer zone 313 and the braking working area 312 are smoothly connected by a small circular arc with a radius of R4, the maximum braking radius R2 of the involute structure braking working area 312 is not less than the radius R3 of the buffer zone 313, and the braking working area 312 and the initial contact area 311 are connected by an arc structure and the working transition area 314. By setting the maximum braking radius R2 of the braking working area 312 with an involute structure to be no less than the radius R3 of the buffer zone 313, a smooth transition connection is achieved. This ensures that when the camshaft 3 rotates to the buffer zone 313, the braking radius will not continue to increase, thus preventing braking dead points and causing jamming or seizure. The maximum braking radius R2 of the braking working area 312 is the maximum braking distance of the entire camshaft 3. The involute structure of the braking working area 312 conforms to the principle that the braking distance gradually increases from small to large, satisfying the requirement that the brake shoe assembly gradually expands to the maximum and reaches the wear limit. The radius R3 of the buffer zone 313 can be equal to or less than the maximum braking radius R2 of the braking working area 312. Specifically, the maximum braking radius R2 of the braking working area 312 and the radius R3 of the buffer zone 313 can also be smoothly connected by an arc larger than R2 and R3. For example, if R3=10, R2 can be 10.2; or R3=10, R2 can be 10; or R3=10, R2 can be 9.8. In this case, R3 and R2 can be smoothly connected by an arc greater than 10, and the connecting arc is the maximum braking radius.

[0037] An alternative implementation, such as Figure 2 , 3 As shown: The camshaft 3 also includes a pivoting part 32 and a connecting part 33 coaxially disposed at the lower end of the cam part 31. The pivoting part 32 is pivotally installed in the camshaft hole 13. The connecting part 33 has a connecting structure adapted to the rocker arm 4 on its outer side. The connecting structure is toothed or splined. The connecting part 33 is also provided with a limiting groove 34. The connecting structure can also be set as a polygonal structure adapted to the polygonal hole on the rocker arm 4. The top of the connecting structure can be threaded and fastened with a nut, or it can be provided with a slot and fastened with a snap ring.

[0038] An alternative implementation, such as Figure 1-4 As shown: A cam seat 35 is provided between the cam part 31 and the pivot part 32. The cam seat 35 is designed as a flat round structure. The pivot part 32 is also provided with an annular groove 36. The annular groove 36 is used to store lubricating oil, so that it can rotate flexibly, reduce friction, and prevent rust.

[0039] An alternative implementation, such as Figure 1 , 2 As shown in Figure 5-7, the second end 22 is also provided with a rolling mechanism 23. The rolling mechanism 23 is pivotally connected to the second end 22 by a cylindrical roller structure, and the cylindrical roller structure is in rolling clamping contact with the cam part 31. By setting the rolling mechanism 23 with the rotatably pivotally connected cylindrical roller structure in the second end 22 and making rolling clamping contact with the cam part 31, the contact friction between the two is reduced, further improving the brake feel, increasing brake sensitivity and rebound speed, resulting in very low braking resistance and a light and comfortable feel.

[0040] An alternative implementation, such as Figure 1 , 2 As shown in Figure 5-7: The second end 22 has a through hole 221 and a connecting groove 222. The connecting groove 222 divides the second end 22 into upper and lower parts along the center layer of the second end 22. The cylindrical roller structure consists of a cylindrical roller 231, a pin 232, and a retaining ring 233. The cylindrical roller 231 is rotatably connected to the second end 22 through the pin 232 and the retaining ring 233. The outer diameter of the cylindrical roller 231 is larger than that of the second end 22 and contacts the cam part 31. By opening the connecting groove 222 in the center layer of the second end 22 for pivotal connection of the cylindrical roller 231, a smooth and reliable connection and flexible rotation are ensured.

[0041] An alternative implementation, such as Figure 5 , 6 As shown: The top of the second end 22 and the outside of the through hole 221 are also provided with a limiting protrusion 223 and a groove 224, and the head end of the pin 232 and the limiting protrusion 223 are provided with a matching anti-rotation surface.

[0042] An alternative implementation, such as Figure 1 , 2 As shown in Figure 5-7: The brake shoe assembly 2 is provided with friction material 24 on the outside. Multiple noise reduction and heat dissipation structures 25 are provided on the friction material 24. The rocker arm 4 is located on the outside of the brake box housing assembly 1 and is detachably connected to one end of the camshaft 3. Rotating the rocker arm 4 drives the camshaft 3 to move the brake shoe assembly 2 around the fixed core shaft 11 to realize the opening and closing action.

[0043] The embodiments disclosed herein are preferred embodiments, but are not limited thereto. Those skilled in the art can readily grasp the spirit of this utility model based on the above embodiments and make different extensions and variations. However, as long as they do not depart from the spirit of this utility model, they are all within the protection scope of this utility model.

Claims

1. A novel hub brake structure, comprising a brake box assembly (1), a brake shoe assembly (2), a camshaft (3), and a rocker arm (4), wherein the brake shoe assembly (2) is provided inside the brake box assembly (1), the first end (21) of the brake shoe assembly (2) is pivotally connected around a centering shaft (12) inside the brake box assembly (1), and the second end (22) of the brake shoe assembly (2) is clamped to the camshaft (3) rotatably disposed in the camshaft hole (13) of the brake box assembly (1), characterized in that: The second end (22) is set as a cylindrical structure that rolls against the cam part (31) of the cam shaft (3). The cross section of the cam part (31) is a smooth transition curve structure composed of a symmetrically arranged initial contact area (311), buffer zone (313) and braking working area (312). When the cam shaft (3) rotates to the transition position between the braking working area (312) and the buffer zone (313), the brake shoe assembly (2) is at the wear limit position.

2. The novel hub brake structure according to claim 1, characterized in that: The initial contact area (311) is set as a concave arc structure, the two buffer zones (313) are set as concentric arc structures, the braking working area (312) is set as an involute structure, and the cross section of the cam part (31) is formed by the symmetrical concave arc structure, involute structure and arc structure connected to each other to form a "gourd" shaped structure.

3. The novel hub brake structure according to claim 2, characterized in that: The maximum braking radius of the braking working area (312) is not less than the radius of the buffer zone (313). The buffer zone (313) and the braking working area (312) are smoothly connected. The braking working area (312) and the initial contact area (311) are connected to the working transition area (314) through an arc structure.

4. The novel hub brake structure according to claim 1, characterized in that: The camshaft (3) also includes a pivot part (32) and a connecting part (33) coaxially disposed at the lower end of the cam part (31). The pivot part (32) is pivotally installed in the camshaft hole (13), and the connecting part (33) has a connecting structure adapted to the rocker arm (4) on its outer side.

5. The novel hub brake structure according to claim 4, characterized in that: The connecting structure is set as a toothed, splined, or polygonal structure, and the connecting part (33) is also provided with a limiting groove (34).

6. The novel hub brake structure according to claim 4, characterized in that: A cam seat (35) is provided between the cam part (31) and the pivot part (32). The cam seat (35) is configured as a flat round structure. The pivot part (32) is also provided with an annular groove (36).

7. The novel hub brake structure according to any one of claims 1-6, characterized in that: The second end (22) is also provided with a rolling mechanism (23), which is pivotally connected to the second end (22) by a cylindrical roller structure and is rotatably connected. The cylindrical roller structure is in rolling clamping contact with the cam part (31).

8. The novel hub brake structure according to claim 7, characterized in that: The second end (22) is provided with a through hole (221) and a connecting groove (222) is also provided on the second end (22). The connecting groove (222) divides the second end (22) into upper and lower parts along the center layer of the second end (22). The cylindrical roller structure is composed of a cylindrical roller (231), a pin (232) and a snap ring (233). The cylindrical roller (231) is rotatably connected to the second end (22) through the pin (232) and the snap ring (233). The outer diameter of the cylindrical roller (231) is larger than that of the second end (22) and contacts the cam part (31).

9. The novel hub brake structure according to claim 8, characterized in that: The second end (22) top and the outside of the through hole (221) are also provided with a limiting protrusion (223) and a groove (224), and the pin (232) head end and the limiting protrusion (223) are provided with a matching anti-rotation surface.

10. The novel hub brake structure according to claim 7, characterized in that: The brake shoe assembly (2) is provided with friction material (24) on the outside. Multiple noise reduction and heat dissipation structures (25) are provided on the friction material (24). The rocker arm (4) is located on the outside of the brake box housing assembly (1) and is detachably connected to one end of the camshaft (3). Rotating the rocker arm (4) drives the camshaft (3) to move the brake shoe assembly (2) around the fixed core shaft (11) to realize the opening and closing action.

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