Drum brake and axle assembly of commercial vehicle

Abstract

The utility model discloses a drum brake of a commercial vehicle and an axle assembly. The drum brake of the commercial vehicle comprises a brake bottom plate, two brake shoes and a cam shaft, the brake shoe comprises a wing plate, two opposite web plates and a friction plate, each web plate comprises a first end and a second end, a pin roller is installed between the first ends of the two web plates, a supporting pin is installed between the second ends of the two web plates, each web plate comprises a first section, a deviation section and a second section, the first section extends to the deviation section from the first end, and the second section extends to the deviation section from the second end. The offset section is connected between the first section and the second section so that the distance between the second sections of the two web plates can be larger than the distance between the first sections of the two web plates. Two pin holes are formed in the brake bottom plate, the supporting pins on the two brake shoes are connected into the two pin holes in a penetrating mode respectively, and the supporting pins are in interference fit with the inner walls of the pin holes. And an S-shaped cam is arranged on the cam shaft and is arranged between the pin rollers on the two brake shoes. According to the utility model, the problem of eccentric wear of the friction plate is solved, and the braking safety of a vehicle is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of commercial vehicles, in particular to a drum brake and an axle assembly of a commercial vehicle. Background Art

[0002] The braking system of a vehicle usually includes two types: disc brakes and drum brakes. The drum brake includes a brake base plate installed on the axle, two opposing brake shoes, a camshaft, and a brake drum. The two brake shoes are located inside the brake drum and are arranged opposite to each other. One end of the brake shoe is rotatably connected to the brake base plate, and the S-shaped cam of the camshaft is placed between the other ends of the two brake shoes. The rotation of the camshaft causes the S-shaped cam to squeeze the other end of the brake shoe, and the two brake shoes swing outward to cause the friction plate on the outside of the brake shoe to contact the inner surface of the wheel hub to generate friction, thereby forming a braking force.

[0003] The brake shoe includes a wing plate, a web plate, and a friction plate. The web plate is fixedly welded to the inner side of the wing plate, a support pin is set at one end of the web plate, and a roller is installed at the other end. The friction plate is fixed to the outer side of the wing plate. One end of the web plate is rotatably connected to the brake base plate through a support pin. The surface of the roller fits with the S-shaped cam surface of the camshaft so that when the S-shaped cam rotates, the rollers of the two brake shoes are squeezed outward, causing the brake shoe to swing outward. In order to make the roller and support pin fit with the brake shoe more stably, two webs with a certain distance between them are usually welded on the inner side of the wing plate. The spacing between the two webs should be adapted to the axial size of the roller to avoid interference between the web and the brake base plate. This results in a smaller axial size of the support pin. The support pin with a smaller axial size is difficult to provide better support for the rotation of the brake shoe, causing the brake shoe to deviate from the axis of the support pin when swinging. After the deflection, the friction pad on the outside of the brake shoe forms an angle when contacting the brake drum, instead of completely affixing to the inner surface of the brake drum. After the drum brake has been used for a certain period of time, the friction pad will experience eccentric wear, that is, one side of the friction pad is more worn and the other side is less worn, which leads to premature friction failure and a shorter service life of the friction pad. Moreover, the friction pad after eccentric wear cannot fully contact the inner surface of the brake drum, causing the friction between the friction pad and the brake drum to decrease, thereby affecting the braking safety of the vehicle. Utility Model Content

[0004] In view of the deficiencies in the prior art, the first object of the utility model is to provide a drum brake for a commercial vehicle, which can solve the problem of eccentric wear of the existing brake shoe friction plate and improve the braking safety of the vehicle.

[0005] The second purpose of the utility model is to provide an axle assembly.

[0006] In order to achieve the above purpose one, the utility model adopts the following technical solution:

[0007] Drum brakes for commercial vehicles, including brake base plates, two opposed brake shoes, and camshafts;

[0008] The brake shoe comprises a wing plate, two opposite web plates fixed on the inner surface of the wing plate, and a friction plate fixed on the outer surface of the wing plate, the web plate comprises a first end and a second end opposite to the first end, a roller is installed between the first ends of the two web plates, and a support pin is installed between the second ends, the web plate comprises a first section, an offset section, and a second section, the first section extends from the first end to the offset section, the second section extends from the second end to the offset section, the offset section is connected between the first section and the second section so that the spacing between the second sections of the two web plates is greater than the spacing between the first sections of the two web plates;

[0009] The brake bottom plate is provided with two pin holes, and the support pins on the two brake shoes are respectively inserted into the two pin holes, and the support pins are interference fit with the inner walls of the pin holes;

[0010] An S-shaped cam is arranged on the camshaft, and the camshaft is connected to the brake base plate so that the S-shaped cam is placed between the rollers on the two brake shoes.

[0011] The offset section is formed by bending one end of the first section away from the first end outwardly so that the offset section on one web extends away from the other web, and the second section is connected to the outer side of the offset section through a bending portion so that the second section is arranged parallel to the first section.

[0012] The spacing between the first sections of the two webs is 36~40mm, and the spacing between the second sections of the two webs is 59~63mm.

[0013] A first tension spring is arranged between the two brake shoes, a tension spring connecting pin is passed through the two webs of the brake shoe, the tension spring connecting pin is passed through one end of the second section of the web close to the offset section, and the two ends of the first tension spring are respectively connected to the tension spring connecting pins on the two brake shoes.

[0014] The drum brake also includes two second tension springs, which are respectively connected between the webs on the same side of the two brake shoes, and the second tension springs are hung on one end of the second section of the web close to the second end.

[0015] The two ends of the support pin are respectively provided with an axis head penetrating from the pin hole, a concave position is arranged on the second end of the web, and the two axis heads are respectively embedded in the concave positions of the two webs.

[0016] In order to achieve the above-mentioned second purpose, the utility model adopts the following technical solutions:

[0017] An axle assembly including the above-mentioned drum brake for a commercial vehicle.

[0018] The beneficial effects of the utility model are:

[0019] In the utility model, an offset section is arranged on the web, so that the spacing between the two webs at the positions for installing the support pins is relatively large, and the spacing between the two webs at the positions for installing the rollers is relatively small, so that the axial size of the rollers meets the requirement of not interfering with the brake base plate, and at the same time the axial size of the support pins is increased. The longer support pins can eliminate the swing angle of the brake shoe when it swings, and prevent the eccentric wear of the friction plate on the brake shoe; at the same time, the support pins are interference fit with the inner wall of the pin hole on the brake base plate, eliminating the fitting clearance between the support pins and the brake base plate, further preventing the brake shoe from swinging, thereby cooperating with the above-mentioned longer-sized support pins to solve the problem of eccentric wear of the friction plate, thereby improving the braking safety of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the utility model;

[0021] Figure 2 for Figure 1 Schematic diagram of the structure of the middle brake shoe;

[0022] Figure 3 for Figure 2 A-direction view;

[0023] Figure 4 for Figure 1 BB cross-sectional view. DETAILED DESCRIPTION

[0024] Below, in conjunction with the accompanying drawings and specific implementation methods, the utility model is further described:

[0025] like Figure 1 , 2, 3, and 4 show a drum brake for a commercial vehicle of the utility model, which includes a brake base plate 10, two brake shoes 20 arranged opposite to each other, and a camshaft (not shown in the figure). The brake shoe 20 includes a wing plate 30, two webs 40, and a friction plate 23, wherein the wing plate 30 is processed into an arc with a middle portion convex outward, the two webs 40 are located on the inner side of the wing plate 30 and are welded and fixed together with the wing plate 30, the two webs 40 are arranged opposite to each other to be spaced a certain distance in the width direction of the wing plate 30, the friction plate 23 is fixedly connected to the outer surface of the wing plate 30, the web 40 is an arc-shaped long strip structure, which includes a first end 401 and a second end 402 opposite to the first end 401, and the two webs 40 are arranged at the inner side of the wing plate 30. There is a roller 21 between the first ends 401, and a support pin 22 is installed between the second ends 402 of the two webs 40, wherein the web 40 includes a first section 41, an offset section 43, and a second section 42, the first section 41 extends from the first end 401 to the offset section 43, the second section 42 extends from the second end 402 to the offset section 43, the offset section 43 is connected between the first section 41 and the second section 42, and in the width direction of the wing plate 30, the side where the offset section 43 connects with the second section 42 is offset to the outside by a certain distance compared with the side where the offset section 43 connects with the first section 41, so that the distance D1 between the first sections 41 of the two webs 40 is smaller than the distance D2 between the second sections 42 of the two webs 40. Two pin holes are provided on the brake base plate 10, and the support pins 22 on the two brake shoes 20 are respectively connected in the two pin holes, and the support pins 22 are interference fit with the inner wall of the pin hole. An S-shaped cam is provided on the camshaft, which is connected to the brake base plate 10 so that the camshaft can rotate relative to the brake base plate 10, and the S-shaped cam is placed between the rollers 21 of the two brake shoes 20. When the camshaft rotates, the S-shaped cam can push the two rollers 21 away from each other, so that the two brake shoes 20 swing away from each other.

[0026] In the utility model, an offset section is arranged on the web, so that the spacing between the two webs at the positions for installing the support pins is relatively large, and the spacing between the two webs at the positions for installing the rollers is relatively small, so that the axial size of the rollers meets the requirement of not interfering with the brake base plate, and at the same time the axial size of the support pins is increased. The longer support pins can eliminate the swing angle of the brake shoe when it swings, and prevent the eccentric wear of the friction plate on the brake shoe; at the same time, the support pins are interference fit with the inner wall of the pin hole on the brake base plate, eliminating the fitting clearance between the support pins and the brake base plate, further preventing the brake shoe from swinging, thereby cooperating with the above-mentioned longer-sized support pins to solve the problem of eccentric wear of the friction plate, thereby improving the braking safety of the vehicle.

[0027] In a preferred embodiment, the offset section 43 on the web 40 of the utility model is formed by two bends on the web 40. Specifically, the offset section 43 has a bend 431 at the junction of the first section 41 away from the first end 401, and the offset section 43 has a bend 432 at the junction of the second section 42 away from the second end 402, wherein the bend 431 is bent outward from the first section 41, and the bend 432 is bent inward from the second section 42. The first section 41 and the second section 42 are arranged in parallel, thereby making the spacing D1 between the first sections 41 of the two webs 40 smaller than the spacing D2 between the second sections 42 of the two webs 40. The spacing between the first sections 41 of the two webs 40 is 36-40 mm, and the spacing between the second sections 42 of the two webs 40 is 59-63 mm.

[0028] A first tension spring 50 is arranged between the two brake shoes 20, and a tension spring connecting pin 24 is connected between the two webs 40 of the brake shoe 20. The tension spring connecting pin 24 is connected to one end of the second section 42 of the two webs 40 close to the offset section 43. The two ends of the first tension spring 50 are respectively connected to the two tension spring connecting pins 24, and the first tension spring 50 provides elastic restoring force for the two brake shoes 20.

[0029] The drum brake further includes two second tension springs 60, which are respectively connected between the webs 40 on the same side of the two brake shoes 20, and the second tension spring 60 is hung on one end of the second section 43 of the web 40 close to the second end 402. The second tension springs 60 make the second end 402 of the web 40 and the support pin 22 cooperate more stably, preventing the second end 402 from being loosened from the support pin 22.

[0030] A shaft head 221 is respectively disposed at both ends of the support pin 22 , and the two shaft heads 221 pass through the two ends of the pin hole respectively. A recess 44 is disposed on the second end 402 of the web 40 , and the two shaft heads 221 are respectively embedded in the recesses 44 of the two webs 40 .

[0031] The axle assembly of the utility model includes the drum brake of the commercial vehicle mentioned above. The other structures of the axle assembly are the same as those in the prior art and will not be described in detail here.

[0032] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein, and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A drum brake for a commercial vehicle, characterized in that: It includes a brake base plate, two opposed brake shoes, and a camshaft; The brake shoe comprises a wing plate, two opposite web plates fixed on the inner surface of the wing plate, and a friction plate fixed on the outer surface of the wing plate, the web plate comprises a first end and a second end opposite to the first end, a roller is installed between the first ends of the two web plates, and a support pin is installed between the second ends, the web plate comprises a first section, an offset section, and a second section, the first section extends from the first end to the offset section, the second section extends from the second end to the offset section, the offset section is connected between the first section and the second section so that the spacing between the second sections of the two web plates is greater than the spacing between the first sections of the two web plates; The brake bottom plate is provided with two pin holes, and the support pins on the two brake shoes are respectively inserted into the two pin holes, and the support pins are interference fit with the inner walls of the pin holes; An S-shaped cam is arranged on the camshaft, and the camshaft is connected to the brake base plate so that the S-shaped cam is placed between the rollers on the two brake shoes.

2. The drum brake for a commercial vehicle according to claim 1, characterized in that: The offset section is formed by bending one end of the first section away from the first end outwardly so that the offset section on one web extends away from the other web, and the second section is connected to the outer side of the offset section through a bending portion so that the second section is arranged parallel to the first section.

3. The drum brake for a commercial vehicle according to claim 2, characterized in that: The spacing between the first sections of the two webs is 36~40mm, and the spacing between the second sections of the two webs is 59~63mm.

4. The drum brake for a commercial vehicle according to claim 1, characterized in that: A first tension spring is arranged between the two brake shoes, a tension spring connecting pin is passed through the two webs of the brake shoe, the tension spring connecting pin is passed through one end of the second section of the web close to the offset section, and the two ends of the first tension spring are respectively connected to the tension spring connecting pins on the two brake shoes.

5. The drum brake for a commercial vehicle according to claim 1, characterized in that: The drum brake also includes two second tension springs, which are respectively connected between the webs on the same side of the two brake shoes, and the second tension springs are hung on one end of the second section of the web close to the second end.

6. The drum brake for a commercial vehicle according to claim 1, characterized in that: The two ends of the support pin are respectively provided with an axis head penetrating from the pin hole, a concave position is arranged on the second end of the web, and the two axis heads are respectively embedded in the concave positions of the two webs.

7. Axle assembly, characterized in that: A drum brake for a commercial vehicle comprising any one of claims 1 to 6.

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