TWI717903B - Drum brake device - Google Patents

Abstract

A drum brake device is provided, which is adapted to brake a wheel hub of a motorcycle. The drum brake device includes a dish, a pin, a first pedal, a first friction material, a second pedal, a second friction material, an elastic unit and a brake cam. The dish includes an axis. The pin is disposed on the dish. The first pedal is rotatably connected to the pin. The first friction material is disposed on the first pedal. The second pedal is rotatably connected to the pin. The second friction material is disposed on the second pedal. The brake cam is disposed on the dish. A first contact area is formed between the first friction material and the wheel hub, a second contact area is formed between the second friction material and the wheel hub, and the first contact area is greater than the second contact area.

Description

Drum brake

The embodiment of the present invention relates to a brake device, and particularly relates to a drum brake device.

The conventional drum brake device includes a first brake shoe, a first friction material, a second brake shoe and a second friction material. The first friction material is arranged on the first brake shoe, and the second friction material is arranged on the second brake shoe. The first friction material and the second friction material are suitable for braking the wheel hub of the locomotive. In the prior art, the size of the first friction material and the second friction material are the same. However, after a long period of use, the wear amount of the first friction material and the second friction material are not the same. This causes a reduction in braking force and affects driving safety.

The embodiment of the present invention provides a drum brake device in order to solve the problems of the prior art, which is suitable for braking a wheel hub of a locomotive, and includes a brake disc seat, a pin, a first brake shoe, A first friction material, a second brake shoe, a second friction material, an elastic unit and a brake cam. The brake disc seat has a disc seat axis. Pin it on the brake disc seat. The first brake shoe is connected to the pin in a rotatable manner. The first friction material is arranged on the first brake shoe. The second brake shoe is connected to the pin in a rotatable manner. The second friction material is arranged on the second brake shoe. The elastic unit is connected to the first brake shoe and the second brake shoe. The brake cam is arranged on the brake disc seat, wherein the brake cam rotates between a first cam orientation and a second cam orientation. When the brake cam is in the first cam orientation, the first brake shoe and the second cam The two brake shoes are folded. The first friction material and the second friction material are not in contact with the wheel hub. When the brake cam is in the second cam position, the first brake shoe and the second brake shoe are spread apart , The first friction material and the second friction material are suitable for contacting the hub, wherein there is a first contact area between the first friction material and the hub, and there is a second friction material between the second friction material and the hub The contact area, the first contact area is larger than the second contact area.

In one embodiment, when the locomotive moves forward, the hub rotates around the brake disc seat in a first direction, and the hub has a reference point. After the reference point passes the pin, the reference point first passes the second The second friction material passes through the brake cam, finally passes through the first friction material, and then returns to the pin.

In one embodiment, the ratio of the second contact area to the first contact area is between 68% and 15%.

In one embodiment, the ratio of the second contact area to the first contact area is between 44% and 31%.

其中，該煞車凸輪包括一第一作用端以及一第二作用端，當該煞車凸輪處於該第二凸輪方位時，該第一作用端推頂該第一煞車蹄片，該第二作用端推頂該第二煞車蹄片，h1為該銷與該第一作用端之間的距離，h2為該銷與該第二作用端之間的距離，b為該銷與該盤座軸心之間的距離，c1為該盤座軸心與該第一摩擦材之間的徑向距離，c2為該盤座軸心與該第二摩擦材之間的徑向距離，μ為該第一摩擦材以及該第二摩擦材的摩擦係數。 In an embodiment, the ratio of the second contact area to the first contact area meets the following relationship:

Wherein, the brake cam includes a first action end and a second action end. When the brake cam is in the second cam orientation, the first action end pushes the first brake shoe, and the second action end pushes Top the second brake shoe, h1 is the distance between the pin and the first acting end, h2 is the distance between the pin and the second acting end, and b is the distance between the pin and the axis of the disc seat , C1 is the radial distance between the disc seat axis and the first friction material, c2 is the radial distance between the disc seat axis and the second friction material, μ is the first friction material And the friction coefficient of the second friction material.

In an embodiment, the elastic unit includes a first spring and a second spring, one end of the first spring is connected to the first brake shoe, the other end of the first spring is connected to the second brake shoe, the One end of the second spring is connected to the first brake shoe, the other end of the second spring is connected to the second brake shoe, the first spring is parallel to the second spring, and the disc seat axis is located between the first spring and Between the second spring.

In another embodiment, the present invention provides a drum brake device suitable for braking a wheel hub of a locomotive, comprising a brake disc seat, a pin, a first brake shoe, a first friction material, and a The second brake shoe, a second friction material, an elastic unit and a brake cam. The brake disc seat has a disc seat axis. Pin it on the brake disc seat. The first brake shoe is connected to the pin in a rotatable manner. The first friction material is arranged on the first brake shoe. The second brake shoe is connected to the pin in a rotatable manner. The second friction material is arranged on the second brake shoe. The elastic unit is connected to the first brake shoe and the second brake shoe. The brake cam is arranged on the brake disc seat, wherein the brake cam rotates between a first cam orientation and a second cam orientation. When the brake cam is in the first cam orientation, the first brake shoe and the second cam The two brake shoes are folded. The first friction material and the second friction material are not in contact with the wheel hub. When the brake cam is in the second cam position, the first brake shoe and the second brake shoe are spread apart , The first friction material and the second friction material are suitable for contacting the wheel hub, wherein the first friction material has a first friction material length in a circumferential direction of the brake disc seat, and the second friction material is in the brake disc seat The circumferential direction has a second friction material length, and the first friction material length is greater than the second friction material length.

By applying the drum brake device of the embodiment of the present invention, the wear amount of the first friction material and the second friction material can be equalized, thereby maintaining the braking force and improving the safety of driving. In one embodiment, it can also be Improve the service life of drum brakes.

Referring to Figure 1, it shows the appearance of the locomotive M according to the embodiment of the present invention, including the faucet 91, the front wheels 92, the rear wheels 93, the seat cushion 94, the power system 95 and other elements.

The locomotive M includes a front section, a middle section, and a rear section. The front section of the locomotive M is provided with components such as a faucet 91, a front wheel 92, a direction lamp, and a keyhole. The middle section of the locomotive M is provided with components such as a power system 95, a cushion 94 and a tripod. The rear section of locomotive M is equipped with components such as taillights, rear wheels 93, and mudguards.

The faucet 91 is used to control the traveling direction of the locomotive M. Functional parts can be installed on the faucet 91, including units such as meters, switches, and rear mirrors. The faucet 91 also has a handle (including a refueling grip) and a hand brake. The user can control the steering of the faucet 91 through the handle, adjust the throttle angle of the power system 95 through the refueling grip to control the power output, and use the hand brake to turn the motorcycle M slow down. The faucet 91 can also be equipped with a main light, which provides the main light for the locomotive M.

The faucet 91 and the front wheel 92 are linked through the faucet rotating shaft, whereby the angle of the front wheel 92 can be controlled through the rotating faucet 91, thereby controlling the traveling direction of the locomotive M.

The power system 95 is connected to and drives the rear wheels 93, thereby providing power to the locomotive M to make the locomotive M move forward.

Figure 2 shows a drum brake device according to an embodiment of the present invention, which is suitable for braking the hub 8 of the wheel of the aforementioned locomotive M. Referring to Figure 2, the drum brake device B includes a brake disc seat 3, a pin 4, a first brake shoe 1, a first friction material 11, a second brake shoe 2, a second friction material 21. An elastic unit 5 and a brake cam 6. The brake disc seat 3 has a disc seat axis 31. The pin 4 is arranged on the brake disc seat 3. The first brake shoe 1 is connected to the pin 4 in a rotatable manner. The first friction material 11 is provided on the first brake shoe 1. The second brake shoe 2 is connected to the pin 4 in a rotatable manner. The second friction material 21 is provided on the second brake shoe 2. The elastic unit 5 is connected to the first brake shoe 1 and the second brake shoe 2. The brake cam 6 is provided on the brake disc seat 3.

Referring to Figure 2, the brake cam 6 rotates between a first cam orientation and a second cam orientation. When the brake cam 6 is in the first cam orientation, the first brake shoe 1 and the second brake shoe The sheet 2 is folded, and neither the first friction material 11 nor the second friction material 21 contacts the hub. When the brake cam 6 is in the second cam orientation, the first brake shoe 1 and the second brake shoe 2 are spread apart, and the first friction material 11 and the second friction material 21 are suitable for contacting the wheel hub 8. There is a first contact area between the first friction material 11 and the hub 8, and a second contact area between the second friction material 21 and the hub 8, and the first contact area is larger than the second contact area. area.

When the material width of the first friction material 11 and the second friction material 21 are the same. The first friction material 11 has a first friction material length L1 in a circumferential direction of the brake disc seat 3, and the second friction material 21 has a second friction material length L2 in the circumferential direction of the brake disc seat 3. The first friction material length L1 is greater than the second friction material length L2.

Referring to Figure 2, in an embodiment, when the locomotive is moving forward, the hub 8 rotates around the brake seat 3 in a first direction α, and the hub 8 has a reference point 81 (virtual reference point) on it. After the reference point 81 passes the pin 4, the reference point 81 first passes the second friction material 21, then passes the brake cam 6, finally passes the first friction material 11, and then returns to the pin 4.

Referring to Figure 2, in an embodiment, the elastic unit 5 includes a first spring 51 and a second spring 52. One end of the first spring 51 is connected to the first brake shoe 1, and the first spring 51 The other end is connected to the second brake shoe 2, one end of the second spring 52 is connected to the first brake shoe 1, the other end of the second spring 52 is connected to the second brake shoe 2, the first spring 51 is parallel In the second spring 52, the disc seat axis 31 is located between the first spring 51 and the second spring 52.

其中，該煞車凸輪6包括一第一作用端61以及一第二作用端62，當該煞車凸輪6處於該第二凸輪方位時，該第一作用端61推頂該第一煞車蹄片1，該第二作用端62推頂該第二煞車蹄片2，h1為該銷4與該第一作用端61之間的距離，h2為該銷4與該第二作用端62之間的距離，b為該銷4與該盤座軸心31之間的距離，c1為該盤座軸心31與該第一摩擦材11之間的徑向距離，c2為該盤座軸心31與該第二摩擦材21之間的徑向距離，μ為該第一摩擦材以及該第二摩擦材的摩擦係數。 Figure 3 shows the design parameters of the drum brake device of the embodiment of the present invention. Referring to Figure 3, in one embodiment, the ratio of the second contact area to the first contact area meets the following relationship:

Wherein, the braking cam 6 includes a first acting end 61 and a second acting end 62. When the braking cam 6 is in the second cam orientation, the first acting end 61 pushes the first brake shoe 1, The second acting end 62 pushes the second brake shoe 2, h1 is the distance between the pin 4 and the first acting end 61, h2 is the distance between the pin 4 and the second acting end 62, b is the distance between the pin 4 and the disc seat axis 31, c1 is the radial distance between the disc seat axis 31 and the first friction material 11, and c2 is the disc seat axis 31 and the first friction material 11 The radial distance between the two friction materials 21, μ is the friction coefficient of the first friction material and the second friction material.

又因為摩擦力Ff1等於反作用力Fn1乘以摩擦係數μ，因此

由以上算式可簡化得

再整理簡化上述算式可得

…(1) The calculation principle of the above formula is explained below. When the drum brake device B brakes, the first acting end 61 of the brake cam 6 applies a force Fa to the first brake shoe 1, and the hub 8 applies the first brake shoe The sheet 1 exerts a reaction force Fn1, and a friction force Ff1 is generated between the hub 8 and the first friction material 11. The sum of the force Fa, the reaction force Fn1, and the friction force Ff1 relative to the pin 4 will be equal to zero, thus obtaining The following relationship:

And because the frictional force Ff1 is equal to the reaction force Fn1 times the friction coefficient μ, so

From the above formula, it can be simplified to

Reorganize and simplify the above formula to get

…(1)

又因為摩擦力Ff2等於反作用力Fn2乘以摩擦係數μ，因此

由以上算式可簡化得

再整理簡化上述算式可得

…(2) 由以上算式(1)(2)整理可得摩擦力Ff1與摩擦力Ff2的關係式為：

Similarly, when the drum brake device B is braking, the second acting end 62 of the brake cam 6 applies a force Fa to the second brake shoe 2, and the hub 8 applies a reaction force to the second brake shoe 2 Fn2, a frictional force Ff2 is generated between the hub 8 and the second friction material 21, and the sum of the moments of the aforementioned acting force Fa, reaction force Fn2, and frictional force Ff2 relative to the pin 4 will be equal to zero, so the following relationship is obtained:

And because the frictional force Ff2 is equal to the reaction force Fn2 times the friction coefficient μ, so

From the above formula, it can be simplified to

Reorganize and simplify the above formula to get

…(2) According to the above formulas (1)(2), the relationship between friction force Ff1 and friction force Ff2 can be obtained as:

在設計上為了讓第一摩擦材11與第二摩擦材21的磨損量相當，因此必須控制第一摩擦材11與第二摩擦材21的面壓相當，換言之，基於             ，該第二接觸面積與該第一接觸面積的比值需符合下列關係式，藉此使得磨耗量保持一致：

In order to make the wear amount of the first friction material 11 and the second friction material 21 equal in design, it is necessary to control the surface pressure of the first friction material 11 and the second friction material 21 to be equal. In other words, based on the fact that the second contact area The ratio of the first contact area must conform to the following relational expression, so as to keep the amount of wear consistent:

In one embodiment, the ratio of the second contact area to the first contact area is between 44% and 31%. Furthermore, in an embodiment of the present invention, the ratio of the second contact area to the first contact area is between 68% and 15%.

By applying the drum brake device of the embodiment of the present invention, the wear amount of the first friction material and the second friction material can be equalized, thereby maintaining the braking force and improving the safety of driving. In one embodiment, it can also be Improve the service life of drum brakes.

In the embodiment of the present invention, a fuel locomotive is taken as an example, however, the above disclosure does not limit the present invention. The locomotive defined in the present invention may include a fuel locomotive, an electric locomotive or other motor vehicles.

Although the present invention has been disclosed in specific preferred embodiments as above, it is not intended to limit the present invention. Anyone familiar with the art can still make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to those defined by the attached patent application scope.

B: Drum brake 1: The first brake shoe 11: The first friction material 2: The second brake shoe 21: The second friction material 3: Brake seat 31: Disc seat axis 4: pin 5: Elastic unit 51: first spring 52: second spring 6: Brake cam 61: first acting end 62: second acting end h1, h2, b, c1, c2: distance 8: Wheel hub 81: reference point L1: Length of the first friction material L2: Length of second friction material α: First direction Fa: force Ff1: friction Ff2: friction Fn1: reaction force Fn2: reaction force 91: Dragon Head 92: front wheel 93: rear wheel 94: cushion 95: Power System M: locomotive

Figure 1 shows the appearance of the locomotive of the embodiment of the present invention. Figure 2 shows a drum brake device according to an embodiment of the present invention. Figure 3 shows the design parameters of the drum brake device of the embodiment of the present invention.

B: Drum brake

1: The first brake shoe

11: The first friction material

2: The second brake shoe

21: The second friction material

3: Brake seat

31: Disc seat axis

4: pin

5: Elastic unit

51: first spring

52: second spring

6: Brake cam

61: first acting end

62: second acting end

8: Wheel hub

81: reference point

L1: Length of the first friction material

L2: Length of second friction material

α: First direction

Claims (2)

A drum brake device, suitable for braking a wheel hub of a locomotive, includes: a brake disc seat with a disc seat axis; a pin arranged on the brake disc seat; and a first brake shoe The pin is connected in a rotating manner; a first friction material is arranged on the first brake shoe; a second brake shoe is connected to the pin in a rotatable manner; a second friction material is arranged on the second brake Shoe; an elastic unit connected to the first brake shoe and the second brake shoe; a brake cam arranged on the brake disc seat, wherein the brake cam is in a first cam orientation and a second cam orientation When the brake cam is in the first cam position, the first brake shoe and the second brake shoe are folded. Neither the first friction material nor the second friction material contact the wheel hub. When the brake When the cam is in the second cam orientation, the first brake shoe and the second brake shoe are spread apart, the first friction material and the second friction material are suitable for contacting the wheel hub, wherein the first friction material and the There is a first contact area between the hubs, and a second contact area between the second friction material and the hub. The first contact area is larger than the second contact area. When the locomotive moves forward, the hub circles The brake disc seat rotates in a first direction, and the hub has a reference point. After the reference point passes the pin, the reference point first passes the second friction material, then the brake cam, and finally passes the first The friction material returns to the pin, where the ratio of the second contact area to the first contact area meets the following relationship:

Wherein, the brake cam includes a first action end and a second action end. When the brake cam is in the second cam orientation, the first action end pushes the first brake shoe, and the second action end pushes Top the second brake shoe, h1 is the distance between the pin and the first acting end, h2 is the distance between the pin and the second acting end, and b is the distance between the pin and the axis of the disc seat , C1 is the radial distance between the disc seat axis and the first friction material, c2 is the radial distance between the disc seat axis and the second friction material, μ is the first friction material And the friction coefficient of the second friction material. For the drum brake device described in item 1 of the patent application, the elastic unit includes a first spring and a second spring, one end of the first spring is connected to the first brake shoe, and the first spring The other end is connected to the second brake shoe, one end of the second spring is connected to the first brake shoe, the other end of the second spring is connected to the second brake shoe, the first spring is parallel to the second spring, The axis of the disc seat is located between the first spring and the second spring.

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