Novel hub brake structure

Abstract

The invention 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 pivotally connected 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] The invention relates to the technical field of brake systems, and in particular to a novel drum brake structure. Background Art

[0002] Drum brakes have been used as brake components on motorcycles and electric vehicles for nearly a century. Their structure is generally a braking device that pushes the brake friction shoe assembly installed in the brake hub outward to cause the brake friction shoe to rub against the brake hub that rotates with the wheel, thereby slowing down or stopping the wheel.

[0003] When the existing hub brake is braking, the rocker arm drives the camshaft to move the left and right brake shoes to open and brake. The camshaft and the brake shoes are in flat contact, and sliding friction is generated between them during actuation. This structural design has low mechanical efficiency, generates large friction resistance, slows the braking process, causes excessively long braking stroke, and poses a safety hazard.

[0004] The contact surface between the brake shoe and the camshaft in the prior art is a plane, and when they move against each other, there is sliding friction, and the force transmission ratio is small. For example, CN110541896A is a vehicle dynamic brake balance hub brake, which has large turning resistance during braking, poor braking feel, and easy wear of the cam and shoe inserts. In addition, since the two ends or one end of the camshaft are usually at the maximum rotation radius position, there is a braking dead point at one end or both ends of the camshaft. After the brake pad has been used for a period of time, the braking idle stroke of the brake device will increase significantly. Continuing to turn the cam until the two ends abut against the shoe is prone to jamming and blocking, causing the brake to fail, thereby affecting safe driving. Summary of the invention

[0005] In response to the deficiencies in the prior art, the present application provides a new hub brake structure, which solves the problems that the contact surface between the existing brake shoe and the camshaft is a flat contact and the mutual actuation is sliding friction, the transmission mechanical efficiency is low, the control resistance is large, and due to the existence of a braking dead point at the end of the camshaft, the brake shoe is prone to wear, sticking, and jamming, causing the brake to fail, thereby affecting safe driving.

[0006] In order to achieve the above objectives, this application adopts the following technical solutions.

[0007] The present invention is a novel hub brake structure, comprising a gate box assembly, a brake shoe assembly, a camshaft and a rocker arm, wherein a brake shoe assembly is arranged on the inner side of the gate box assembly, a first end portion of the brake shoe assembly is pivotally connected around a centering rotating shaft in the gate box assembly, a second end portion of the brake shoe assembly is clamped with a camshaft rotatably arranged in a camshaft hole of the gate box assembly, the second end portion is arranged as a cylindrical structure to rollably abut against a cam portion of the camshaft, a cross section of the cam portion is a smooth transition curve structure consisting of a symmetrically arranged initial abutment area, a buffer area and a braking working area, and when the camshaft rotates to a transition position between the braking working area and the buffer area, the brake shoe assembly is in a wear limit position.

[0008] Further improvements are: the initial abutment area is set as a concave arc structure, the two buffer zones are set as concentric arc structures, the braking working area is set as an involute structure, and the cross-section of the cam part is composed of symmetrically arranged concave arc structures, involute structures, and arc structures connected to each other to form a "gourd" shape structure.

[0009] A further improvement is that 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 abutment area are transitionally connected to the working transition zone through an arc structure.

[0010] A further improvement is that the camshaft further comprises a pivoting portion and a connecting portion coaxially arranged at the lower end of the cam portion, the pivoting portion is pivotally mounted in the camshaft hole, and a connecting structure adapted to the rocker arm is provided on the outer side of the connecting portion.

[0011] A further improvement is that the connection structure is configured as a toothed, splined or polygonal structure, and a limiting groove is further provided on the connection portion.

[0012] A further improvement is that a cam seat is provided between the cam portion and the pivot portion, the cam seat is configured as an oblate structure, and the pivot portion is further provided with an annular groove.

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

[0014] Further improvements are: a through hole is opened in the second end portion, and a connecting groove is also provided on the second end portion, and the connecting groove divides the second end portion into an upper and lower part along the center layer of the second end portion; the cylindrical roller structure consists of a cylindrical roller, a pin shaft and a retaining spring; the cylindrical roller is rotatably connected to the second end portion through the pin shaft and the retaining spring; the outer diameter of the cylindrical roller is larger than the second end portion and contacts the cam portion.

[0015] A further improvement is that a limiting protrusion and a groove are further provided at the top of the second end portion and the outer side of the through hole, and the pin shaft head end and the limiting protrusion are provided with matching anti-rotation surfaces.

[0016] Further improvements are: friction material is provided on the outside of the brake shoe assembly, and multiple noise-absorbing and heat-dissipating structures are opened on the friction material. The rocker arm is arranged on the outside 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 rotating shaft to realize opening and closing actions.

[0017] Compared with the prior art, the present invention has the following beneficial effects: By arranging a cylindrical arc surface at the second end of the brake shoe assembly to roll with the cam portion of the camshaft, the existing surface contact between the brake shoe assembly and the camshaft is changed to rolling contact, and the sliding friction is changed to rolling friction, thereby reducing the braking friction resistance of the two, thereby improving the braking mechanical efficiency of the brake assembly; while ensuring that the braking stroke remains unchanged, the output transmission ratio of the camshaft is increased through the involute curved surface design, thereby reducing the braking resistance force, 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, thereby extending the overall service life of the hub brake; By setting a cam portion with a smooth transition curve structure consisting of a symmetrical initial abutment area, a braking working area and a buffer area on the camshaft and rollingly abutting the second end, when the camshaft rotates to the buffer areas at both ends and abuts the second end, since the braking working area and the buffer area are smoothly transitioned, and the maximum braking radius of the braking working area is not less than the radius of the buffer area, there is no braking dead point, and there will be no jamming or stagnation due to the braking dead point, resulting in brake failure, thereby affecting safe driving; At the same time, when the camshaft rotates to the transition position between the braking working area and the buffer zone, the brake shoe assembly is at the wear limit position, that is, after the brake shoe is stretched to the maximum limit position, turning to the buffer zone will only result in the braking effect being unclear. There is no need to add a wear reminder structure to accurately remind that the brake shoe assembly needs to be replaced, ensuring safe driving needs.

[0018] Since the maximum braking radius of the braking working area is the maximum braking distance of the entire camshaft, the braking working area is set to an involute structure to meet the braking radius and gradually increase the braking distance from small to large to meet the brake shoe assembly gradually expanding to the maximum to reach the wear limit. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention; Figure 2 It is an exploded view of the present invention; Figure 3is a stereoscopic diagram of the camshaft of the present invention; Figure 4 The present invention Figure 3 Top view; Figure 5 It is a three-dimensional schematic diagram of a brake shoe on one side of the present invention; Figure 6 It is an exploded view of the rolling mechanism of the brake shoe on one side of the present invention; Figure 7 It is a schematic diagram of the working position of the camshaft of the present invention.

[0020] Figure ID: Brake box assembly-1, central axis hole-11, centering 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, retaining spring-233, friction material-24, sound-absorbing and heat-dissipating structure-25, camshaft-3, cam portion-31, initial abutment area-311, braking working area-312, buffer zone-313, pivot portion-32, connecting portion-33, limiting groove-34, cam seat-35, annular groove-36, rocker arm-4. DETAILED DESCRIPTION

[0021] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings. This embodiment is only used to explain the present invention and does not constitute a limitation on the protection scope of the present invention.

[0022] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as "center", "up", "down", "front", "back", "left" and "right" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the combination or elements referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the present invention.

[0023] The present invention will be further described below with reference to the accompanying drawings and in combination with embodiments.

[0024] like Figure 1-5The figure shows a novel hub brake structure, including a brake box assembly 1, a brake shoe assembly 2, a camshaft 3 and a rocker arm 4. A central axis hole 11 is provided at the center of the brake box assembly 1, and a fixed core rotating shaft 12 and a camshaft hole 13 are symmetrically provided on both sides of the central axis hole 11. The brake shoe assembly 2 is installed on the inner side of the brake box assembly 1, and the first end 21 of the brake shoe assembly 2 is set as an arc structure and pivotally connected around the fixed core rotating shaft 12. The second end 22 of the brake shoe assembly 2 is clamped with one end of the camshaft 3 rotatably set in the camshaft hole 13 of the brake box assembly 1. The rocker arm 4 is connected to the outer side of the brake box assembly 1 through the other end of the camshaft 3. The left and right brake shoes of the component 2 are respectively provided with return springs to enable the brake shoe component to have a return driving force. The second end 22 is set as a cylindrical structure to roll and abut against the cam portion 31 of the camshaft 3. The cross section of the cam portion 31 is a smooth transition curve structure composed of a symmetrically arranged initial abutment area 311, a buffer area 313 and a braking working area 312 connecting the initial abutment area 311 and the buffer area 313. The camshaft 3 rotates to the transition position between the braking working area (312) and the buffer area (313) and abuts against the second end 22. The brake shoe component 2 is at the wear limit position, that is, the maximum limit position of the brake shoe component 2.

[0025] By setting a cylindrical curved surface at the second end 22 of the brake shoe assembly to roll with the cam portion 31 of the camshaft 3, the existing surface contact between the brake shoe assembly and the camshaft is changed to rolling contact, thereby reducing the initial braking friction between the two, thereby reducing the braking resistance force and improving the braking mechanical efficiency of the brake assembly; the cylindrical curved surface at the second end 22 is set to roll with the cam portion 31 of the camshaft 3. The force arm relative to the rotation center of the camshaft 3 is shortened, thereby increasing the transmission ratio of the camshaft 3 transmission output, improving the lightness and comfort of the braking feel, and thus improving the problem of heavy braking feel; because 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. , which prolongs 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 abutment area 311, a braking working area 312 and a buffer area 313 on the camshaft 3, and rollingly abutting against the second end portion, the camshaft 3 rotates to the buffer areas 313 at both ends. Since the braking working area 312 and the buffer area 313 are smoothly transitioned and there is no braking dead point, only the braking effect is not obvious, and there will be no braking failure caused by jamming or stagnation due to the braking dead point, thereby affecting safe driving; at the same time, when the camshaft 3 rotates to the buffer area 313, only the braking effect is not obvious, and there is no need to add a wear prompt structure to accurately prompt the need to replace the brake shoe assembly, thereby ensuring the need for safe driving.

[0026] An optional implementation method, such as Figure 3 , 4As shown: the initial abutment area 311 is set as an inward concave arc structure, the radii of the two concave arcs are set as R1, 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 portion 31 is formed by a symmetrically arranged inward concave arc structure, an involute structure, and an arc structure that are interconnected to form a "gourd" structure; the buffer zone 313 and the braking working area 312 are smoothly connected by a small arc with a radius of R4, the maximum braking radius R2 of the braking working area 312 of the involute structure is not less than the radius R3 of the buffer zone 313, and the braking working area 312 and the initial abutment area 311 are transitionally connected to the working transition area 314 through an arc structure. By setting the maximum braking radius R2 of the braking working area 312 of the involute structure to be not less than the radius R3 of the buffer zone 313, a smooth transition connection is achieved to ensure that the braking radius will not continue to increase when the camshaft 3 rotates to the buffer zone 313, and there will be no braking dead point to cause stagnation or jamming; the maximum braking radius R2 of the braking working area 312 is the maximum braking distance of the entire camshaft 3, and the braking working area 312 is set as an involute structure to meet the braking radius gradually increasing the braking distance from small to large to meet the brake shoe assembly gradually expanding to the maximum to reach the wear limit; the radius R3 of the buffer zone 313 can be equal to the maximum braking radius R2 of the braking working area 312, or it can be less than. 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, such as: R3=10, R2 can be 10.2; or R3=10, R2 can be 10, or R3=10, R2 can be 9.8, then R3 and R2 can be smoothly connected by an arc larger than 10, and the connecting arc is the maximum braking radius.

[0027] An optional implementation method, such as Figure 2 , 3 As shown: the camshaft 3 also includes a pivot portion 32 and a connecting portion 33 coaxially arranged at the lower end of the cam portion 31. The pivot portion 32 is pivotally installed in the camshaft hole 13, and a connecting structure adapted to the rocker arm 4 is provided on the outer side of the connecting portion 33; the connecting structure is configured to be toothed or splined, and a limiting groove 34 is also provided on the connecting portion 33; the connecting structure can also be configured to be a polygonal structure adapted to the polygonal hole on the rocker arm 4, and a thread can be provided on the top of the connecting structure to be fastened by a nut, or a slot can be provided to be connected by a retaining spring buckle.

[0028] An optional implementation method, such as Figure 1-4 As shown: a cam seat 35 is provided between the cam portion 31 and the pivot portion 32. The cam seat 35 is set as an oblate structure. The pivot portion 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.

[0029] An optional implementation method, such as Figure 1 , 2 , 5-7: 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 can be rotatably connected, and the cylindrical roller structure is in rolling and clamping contact with the cam portion 31. By setting the rolling mechanism 23 of the cylindrical roller structure that is pivotally connected at the second end 22 and in rolling and clamping contact with the cam portion 31, the contact friction between the two is reduced, the braking feel is further improved, the braking sensitivity is increased, and the rebound speed is faster, which is manifested as a small braking resistance, light and comfortable feel.

[0030] An optional implementation method, such as Figure 1 , 2 , 5-7: The second end portion 22 is provided with a through hole 221, and a connecting groove 222 is also provided on the second end portion 22. The connecting groove 222 divides the second end portion 22 into two parts, an upper part and an lower part, along the center layer of the second end portion 22. The cylindrical roller structure is composed of a cylindrical roller 231, a pin 232 and a retaining spring 233. The cylindrical roller 231 is rotatably connected to the second end portion 22 through the pin 232 and the retaining spring 233. The outer diameter of the cylindrical roller 231 is larger than that of the second end portion 22 and contacts the cam portion 31. By providing a connecting groove 222 in the center layer of the second end portion 22 for pivotally connecting the cylindrical roller 231, a stable and reliable connection and flexible rotation are ensured.

[0031] An optional implementation method, such as Figure 5 , 6 As shown: a limiting protrusion 223 and a groove 224 are further provided at the top of the second end portion 22 and the outer side of the through hole 221 , and a matching anti-rotation surface is provided at the head end of the pin shaft 232 and the limiting protrusion 223 .

[0032] An optional implementation method, such as Figure 1 , 2 As shown in 5-7: a friction material 24 is provided on the outer side of the brake shoe assembly 2, and a plurality of noise-absorbing and heat-dissipating structures 25 are provided on the friction material 24. A rocker arm 4 is arranged on the outer side 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 rotating shaft 11 to realize the opening and closing action.

[0033] The embodiments of the present invention disclose preferred embodiments, but are not limited thereto. A person skilled in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and changes. However, as long as they do not deviate from the spirit of the present invention, they are all within the protection scope of the present invention.

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 a brake shoe assembly (2) is provided inside the brake box assembly (1), a first end portion (21) of the brake shoe assembly (2) is pivotally connected around a fixed centering shaft (12) inside the brake box assembly (1), and a second end portion (22) of the brake shoe assembly (2) is clamped and arranged to be rotatably arranged in a camshaft hole (13) of the brake box assembly (1), characterized in that: The second end portion (22) is configured as a cylindrical structure that rolls against the cam portion (31) of the camshaft (3); the cross section of the cam portion (31) comprises a smooth transition curve structure consisting of a symmetrically arranged initial contact area (311), a buffer area (313) and a braking working area (312); when the camshaft (3) rotates to a transition position between the braking working area (312) and the buffer area (313), the brake shoe assembly (2) is at a wear limit position.

2. The novel hub brake structure according to claim 1 is characterized in that: The initial contact area (311) is configured as an inwardly concave arc structure, the two buffer areas (313) are configured as concentric circular arc structures, the braking working area (312) is configured as an involute structure, and the cross section of the cam portion (31) is composed of a symmetrically arranged inwardly concave arc structure, an involute structure, and an circular arc structure that are interconnected to form a "gourd"-shaped structure.

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

4. The novel hub brake structure according to claim 1 is characterized in that: The camshaft (3) further comprises a pivoting portion (32) and a connecting portion (33) coaxially arranged at the lower end of the cam portion (31); the pivoting portion (32) is pivotally mounted in the camshaft hole (13); and a connecting structure adapted to the rocker arm (4) is provided on the outer side of the connecting portion (33).

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

6. The novel hub brake structure according to claim 4 is characterized in that: A cam seat (35) is further provided between the cam portion (31) and the pivot portion (32); the cam seat (35) is configured as an oblate structure; and the pivot portion (32) is further provided with an annular groove (36).

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

8. The novel hub brake structure according to claim 7 is characterized in that: The second end portion (22) is provided with a through hole (221), and the second end portion (22) is also provided with a connecting groove (222), the connecting groove (222) dividing the second end portion (22) into an upper and lower part along the center layer of the second end portion (22), the cylindrical roller structure comprising a cylindrical roller (231), a pin shaft (232) and a retaining spring (233), the cylindrical roller (231) being rotatably connected to the second end portion (22) via the pin shaft (232) and the retaining spring (233), the outer diameter of the cylindrical roller (231) being larger than the second end portion (22) and being in contact with the cam portion (31).

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

10. The novel hub brake structure according to claim 7, characterized in that: The outer side of the brake shoe assembly (2) is provided with a friction material (24), and a plurality of noise-absorbing and heat-dissipating structures (25) are provided on the friction material (24). The rocker arm (4) is arranged on the outer side 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 rotating shaft (11) to realize an opening and closing action.

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