JPH0960664A - Vehicular brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular brake whose rotational resistance is small and which is silent at the time of travelling. SOLUTION: A notch 42e having a spring seat 42c is arranged in the center of a brake shoe 42, and a shoe stopper 46 is arranged to be fitted to the notch 42e. A V-shaped plate spring 50 is arranged between the spring abutting part 46a of the shoe stopper 46 and the spring seat 42c of the brake shoe 42. When a driving cam 32 is rotated in a direction opposite to a Q2 direction, the brake shoe 42 is forcibly moved in the inward of a radial direction together with a roller 38 by the restoring force of the plate spring 50 so that the roller 38 is brought in contact with the cam surface 32a of the driving cam 32. Hereby, at the time of travelling, the brake shoe 42 and a drum 44 completely get out of contact with other. Also, play between the brake shoe 42 and the roller 38 is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake for a vehicle, and more particularly to a roller brake used for a bicycle or the like.

[0002]

2. Description of the Related Art As a brake for a bicycle,
Roller brakes are known. FIG. 5 shows the configuration of a roller brake 2 of a conventional bicycle. When the bicycle is running, as shown in FIG. 5A, the drum 4 directly connected to the bicycle wheel (not shown) does not receive the pressing force of the brake shoe 6 and can rotate freely.

[0005] As shown in FIG. 5B, the operation wire 8 is connected to P1.
When operated in the direction, the cam 10 rotates in the P2 direction. With the rotation of the cam 10 in the P2 direction, the brake shoe 6 is pressed against the inner surface 4a of the drum 4 via the roller 12. On the other hand, the brake shoe 6 is prevented from rotating by a shoe stopper (not shown) provided on the brake arm 14.

Therefore, the drum 4 has the brake shoe 6
The rotation is suppressed by the frictional force acting between the first and second members. In this way, the bicycle can be braked by operating the operation wire 8 in the P1 direction.

When the operating wire 8 is released from the state of FIG. 5B, the cam 10 is urged by the urging force of the brake return spring 18.
Rotates in the direction opposite to the P2 direction and returns to the state of FIG. 5A. As a result, the pressing of the brake shoe 6 against the inner surface 4a of the drum 4 is released, and the drum 4 is again in a state where it can freely rotate.

[0006]

However, the conventional roller brake 2 as described above has the following problems. As described above, in the conventional roller brake 2, when the operation wire 8 is released, the brake return spring 1 is released.
By the biasing force of 8, the cam 10 is forcibly rotated in the direction opposite to the P2 direction. However, the urging force of the brake return spring 18 cannot be a force that separates the brake shoe 6 from the drum 4.

Therefore, when the inner space 16 of the roller brake 2 is filled with grease or the like, the inner surface 4a of the drum 4 and the brake shoe 6 are in a state of being adhered to each other through the grease, and thus when the bicycle is running. Especially, in the early stage of running when the temperature of the grease is low, the rotational resistance of the wheel is generated due to the viscous resistance of the grease. This rotation resistance is prominent in winter, when the viscosity of grease increases, and in cold regions. Therefore, power loss occurs when the bicycle is running.

On the other hand, when the operating wire 8 is released, the brake shoe 6 is in a play state. Therefore, particularly when the inner space 16 of the roller brake 2 is not filled with grease or the like, noise is generated due to rattling of the brake shoes 6 when the bicycle is running.

An object of the present invention is to solve the problems of the conventional vehicle brakes such as the roller brake 2 and to provide a quiet vehicle brake which has a small rotational resistance during traveling. .

[0010]

According to a first aspect of the present invention, there is provided a brake for a vehicle, wherein the fixed member is fixed to a vehicle, and is rotatably supported by the fixed member. A brake body having a substantially cylindrical braking inner wall at the center, a plurality of brake bodies are arranged on substantially the same circumference around the rotation axis inside the braking inner wall of the brake body, and are not rotatable with respect to the fixed member and A friction member that is supported movably in the radial direction of the rotation shaft, has a friction surface that can abut against the braking inner wall, and a pressing surface provided on the back side of the friction surface, the friction member being provided inside the pressing surface of the friction member. A plurality of rolling elements that are arranged on substantially the same circumference around the rotation axis and that can press the pressing surface, are disposed inside the rolling elements, are rotatably supported by the fixed member, and The cam surface that can move the rolling element in the radial direction of the rotation shaft In a vehicular brake including a cam body, an elastic body is interposed between the fixed member and the friction body or between the friction bodies, and friction is applied so that the braking inner wall of the braking body and the friction surface of the friction body are separated from each other. It is characterized by having urged the body.

A vehicle brake according to a second aspect is the vehicle brake according to the first aspect, in which a spring seat displaced toward the pressing surface side with respect to the friction surface is provided on the friction surface side of the friction body,
A spring contact portion is provided at a position facing the spring seat of the friction body, and between the spring seat of the friction body and the spring contact portion of the fixing member is substantially the same as the direction in which the friction body is separated from the braking body. An elastic body that urges in the direction is arranged.

A vehicle brake according to a third aspect is the vehicle brake according to the second aspect, characterized in that the spring seat is provided substantially at the center of the friction body.

A vehicle brake according to a fourth aspect of the present invention is the vehicle brake according to the second or third aspect, wherein the vehicle brake is fixedly disposed inside the braking inner wall of the braking body with respect to the fixed member to rotate the friction body. In addition to providing a friction body rotation blocking piece for blocking,
The friction body rotation preventing piece is provided with a spring contact portion.

[0014]

The vehicle brake according to the first aspect of the invention is characterized in that the elastic body is interposed and the friction body is biased so that the braking inner wall of the braking body and the friction surface of the friction body are separated from each other.

Therefore, during traveling, the braking inner wall of the braking body does not come into contact with the friction surface of the friction body. Therefore, rotation resistance due to contact between the braking body and the friction body cannot occur during traveling. Further, the friction body is pressed against the rolling element by the elastic body during traveling. Therefore, the friction body or the like does not rattle. That is, when traveling,
It is possible to realize a quiet vehicle brake with low rotation resistance.

The vehicle brake according to claim 2 is further provided between the spring seat of the friction member and the spring contact portion of the fixing member in a direction substantially the same as the direction in which the friction member is separated from the braking member. It is characterized in that a biasing elastic body is arranged.

Therefore, the friction body can be efficiently separated from the braking body by a slight biasing force.
Therefore, the elastic body can be made smaller. That is, it is possible to further reduce the size of the vehicle brake.

The vehicle brake according to claim 3 is further characterized in that a spring seat is provided substantially at the center of the friction body.

Therefore, the substantial center of the friction body is thinner than the other parts. Therefore, during braking, the pressing force of the rolling elements makes it easier for the friction body to bend, and the friction surface of the friction body tends to follow the braking surface of the braking body. That is, the braking ability is further improved. Further, the number of processing points of the friction body is reduced as compared with the case where the spring seats are provided at both ends of the friction body. That is, it is possible to further reduce the cost of the vehicle brake.

A vehicle brake according to a fourth aspect of the invention is further characterized in that a friction member rotation preventing piece for preventing rotation of the friction member is provided with a spring contact portion.

Therefore, the friction body rotation preventing piece and the spring contact portion can be used in common. For this reason, it is not necessary to separately provide a spring contact portion other than the friction body rotation preventing piece. That is, it is possible to further reduce the size of the vehicle brake.

[0022]

FIG. 2 is a view of a hub portion of a rear wheel of a bicycle using a roller brake 22 which is a vehicle brake according to an embodiment of the present invention, as viewed from the rear of the bicycle (half sectional view). Indicates.

As shown in FIG. 2, a hub 26 is rotatably supported by a hub shaft 24 fixed to a frame (not shown) of a bicycle, which is a vehicle. The hub 26 is a hub body 2
6c and a pair of disk-shaped hub flanges 2 formed at both ends thereof
6a and 26b. Via spokes (not shown) stretched substantially radially from the hub flanges 26a, 26b,
A rim (not shown), a tire (not shown), etc. are held. A rear wheel is constituted by the hub 26, spokes, rims, tires and the like.

The roller brake 22 is arranged outside the left (X1 direction) of the hub 26. A freewheel 28 that transmits the driving force of a chain (not shown) to the hub 26 only in one direction is provided on the right side (X2 direction) of the hub 26.
Is arranged.

FIG. 1 shows a view (partial cross-sectional view) of the roller brake 22 as seen from V1 in FIG. The structure of the roller brake 22 will be described with reference to FIG. 1 while referring to FIG. A driving cam 32 as a cam body is rotatably supported on the outer periphery of the ball pusher 30 screwed to the hub shaft 24.

On the outer periphery of the drive cam 32, a plurality of cam surfaces 32a formed in the same shape are provided so as to move a roller 38, which will be described later, in the radial direction around the hub shaft 24. The cam surface 32a is formed so as to push the roller 38 radially outward as the drive cam 32 rotates in the Q2 direction.

The drive cam 32 and the operating arm 34 are connected by a serration S1 so that they cannot rotate relative to each other.
A wire W is connected to a distal end of the operation arm 34 via a wire stopper 36. In addition, the wire stopper 36
Is connected to one end of a brake return spring 56 for urging the operation arm 34 in a direction opposite to the Q2 direction.

A plurality of cam surfaces 3 provided on the drive cam 32
Rollers 38, each of which is a rolling element, are arranged at a position facing 2a. A retainer 40 is provided to keep the position of the roller 38 in the circumferential direction (circumferential direction around the hub shaft 24) substantially constant.

A brake shoe 42, which is a frictional member, is disposed on the outer side of the roller 38 in the radial direction (radial direction around the hub shaft 24). The brake shoe 42
A pressing surface 42a pressed by the roller 38 and a friction surface 42b provided on the opposite side of the pressing surface 42a and in contact with a braking inner wall 44a of a drum 44 described later are provided. The pressing surface 42a and the friction surface 42b of the brake shoe 42 are formed in a concentric arc shape with the hub shaft 24 as a center.

A notch 42e, which is composed of a spring seat 42c and a locking surface 42d, which are formed stepwise with respect to the friction surface 42b, is provided substantially in the center of the brake shoe 42.

In this embodiment, three brake shoes 42 having the same shape are provided, and these brake shoes 42 are arranged in an arc shape to divide the circumference into three parts. The brake shoe 42 is formed of a steel material.

A shoe stopper 46, which is a friction body rotation preventing piece, is provided so as to be fitted into the notch 42e.
The shoe stopper 46 is formed by standing a part of a brake arm 48, which is a fixing member described later, in the X2 direction shown in FIG. A spring contact portion 46a of the shoe stopper 46,
A "ku" is provided between the brake shoe 42 and the spring seat 42c.
A leaf spring 50, which is an elastic body formed in a U-shape, is disposed.

Radially outward of the brake shoe 42,
A cylindrical drum 44 serving as a braking body is provided. The drum 44 is generally made of a steel material, and forms a braking inner wall 44a by sintering a sintered metal friction material on the inner surface of the steel material. In this example, as a raw material of the sintered metal friction material, copper as a main component,
An alloy powder containing tin, iron, lead, zinc, graphite, silica, etc. is used. Braking inner wall 44a and brake shoe 42
The friction coefficient with the friction surface 42b is about 0.5 to 0.8. Further, the thickness of the sintered metal friction material is about 0.5 mm.

As shown in FIG. 2, the base portion 44 of the drum 44 is
The cylindrical portion b and the cylindrical portion 26d formed on the left outside of the hub flange 26a of the hub 26 are connected to each other by a serration S2 so as not to rotate relatively. That is, the roller brake 22
Drum 44 is rotatably supported by the hub shaft 24 integrally with the hub 26.

Further, as shown in FIG. 2, the brake arm 48 and the cover 52 are formed by the left outer end surface 30a of the ball pusher 30 screwed to the hub shaft 24 and the lock nut 54.
It is clamped immovably in the X1 and X2 directions.
The brake arm 48 is further fixed to a bicycle frame (not shown), whereby the rotation of the brake arm 48 with respect to the hub shaft 24 is completely prevented.

Next, the operation of the roller brake 22 will be described. FIG. 1 is a diagram showing a state during braking. When the wire W is operated by a brake lever (not shown), Q1
Tow in the direction. As a result, the operation arm 34 and the driving cam 32 rotate in the Q2 direction via the wire stopper 36.

When the drive cam 32 rotates in the Q2 direction, the roller 38 rolls on the cam surface 32a by the action of the cam surface 32a formed on the outer periphery of the drive cam 32.
It is pushed outward in the radial direction (radial direction about the hub shaft 24).

The pushed roller 38 pushes the brake shoe 42 radially outward while rolling on the pressing surface 42a of the brake shoe 42. The friction surface 42b of the pushed brake shoe 42 is connected to a braking inner wall 44 of a drum 44 which rotates integrally with the hub 26 (see FIG. 2).
a with a predetermined force. Therefore, a frictional force corresponding to the pressing force is generated between the friction surface 42b of the brake shoe 42 and the braking inner wall 44a of the drum 44.

On the other hand, the brake shoe 42 has a locking surface 42.
Due to the engagement between d and the shoe stopper 46, the rotation about the hub shaft 24 is prevented. For this reason, the above-mentioned frictional force becomes a braking force for braking the drum 44.

Braking torque T generated on the drum 44
_out is represented by the following equation (see FIG. 3): T _out = μ _drm × D _drm / (D _cam × (sin α + μ _r × cos
α)) × T _in .

However, T _out : Braking torque generated on the drum 44 μ _drm : Friction coefficient between the friction surface 42b of the brake shoe 42 and the braking inner wall 44a of the drum 44 D _drm : Inner diameter of the drum 44 D _cam : Drive cam 32 Diameter of contact between roller 38 and roller α: Cam angle μ _r : Rolling friction coefficient of roller 38 T _in : Input torque applied to drive cam 32.

As described above, the braking inner wall 44a of the drum 44 is formed of a sintered metal friction material whose main component is copper whose friction coefficient and thermal conductivity are higher than those of steel materials, and the brake shoes are made of steel materials. The reason why the seizure between the drum 44 and the brake shoe 42 is less likely to occur due to the formation by the above method is not necessarily clear, but the applicant considers as follows.

That is, first, since the friction coefficient of the sintered metal friction material is large, the pressing force of the brake shoe 42 required to obtain a predetermined braking force can be small. Therefore,
Excessive frictional heat is unlikely to be generated between the drum 44 and the brake shoe 42 during braking.

Second, since the sintered metal friction material has a high thermal conductivity, the frictional heat generated between the drum 44 and the brake shoe 42 is quickly conducted and diffused to other portions. Therefore, the temperatures of the drum 44 and the brake shoe 42 do not rise so much.

Thirdly, the braking inner wall 44a of the drum 44 and the brake shoe 42 are made of different materials. That is, the friction surfaces are different metals. For this reason, even if the temperatures of the drum 44 and the brake shoe 42 are increased, it is considered that seizure is less likely to occur as compared with the case of friction between similar metals.

Next, when the brake lever (not shown) is released from the braking state shown in FIG. 1, the tension of the wire W in the Q1 direction is also released. For this reason, the wire stopper 3
The operation arm 34 and the drive cam 32 are forcibly rotated in the direction opposite to the Q2 direction by the restoring force of the brake return spring 56 transmitted via the actuator 6.

With the rotation of the drive cam 32 in the direction opposite to the Q2 direction, the pressing force applied to the drum 44 by the brake shoe 42 via the roller 38 is reduced to 0.
Becomes Therefore, the frictional force between the two based on the pressing force is also zero. As a result, the braking on the drum 44 is released.

Further, with the rotation of the drive cam 32 in the direction opposite to the Q2 direction, the roller 38 and the brake shoe 42 can be moved inward in the radial direction. On the other hand, due to the restoring force of the leaf spring 50 disposed between the spring contact portion 46a of the shoe stopper 46 and the spring seat 42c of the brake shoe 42, the brake shoe 42 is forced inward in the radial direction together with the roller 38. Is moved,
The roller 38 comes into contact with the cam surface 32a of the drive cam 32.

Therefore, at the same time when the braking is released,
The contact between the brake shoe 42 and the drum 44 is completely cut off. Also, rattling of the brake shoe 42 and the roller 38 is prevented.

Next, FIG. 4 shows a part of the structure of the roller brake 62 according to another embodiment of the present invention. The roller brake 62 has a spring seat 64c provided on a brake shoe 64 provided at an end of the brake shoe 64, and a roller brake 22 (where a spring seat 42c is provided substantially at the center of the brake shoe 42). (See FIG. 1).

That is, the roller brake 6 shown in FIG.
2, the friction surface 6 is attached to the end of the brake shoe 64.
An L-shaped notch 64e, which includes a spring seat 64c and a locking surface 64d formed stepwise with respect to 4b, is provided. A notch 64f is provided at substantially the center of the brake shoe 64 in order to make the brake shoe 64 easy to bend and make the drum 44 better along the braking inner wall 44a.

Brake shoes 64 are arranged adjacent to each other so as to sandwich the shoe stopper 46. Also,
Adjacent spring seat 64c of adjacent brake shoe 64
A leaf spring 50 is arranged between the spring stopper 46 and the spring contact portion 46 a of the shoe stopper 46. Other points are shown in Figure 1.
Is the same as the roller brake 22 shown in FIG.

In each of the above-described embodiments, the friction coefficient between the braking inner wall 44a and the friction surface 42b of the brake shoe 42 is set to about 0.5 to 0.8, and the thickness of the sintered metal friction material is set. Was about 0.5 mm, but the present invention is not limited to this. Further, the present invention is directed to the braking inner wall 4
4A and the friction surface 42b of the brake shoe 42 or the like can be applied regardless of whether it is a wet type in which rust-preventing oil or the like is interposed or a dry type in which it is not interposed.

Further, although only the braking inner wall 44a of the drum 44 is made of the sintered metal friction material and the other portion of the drum 44 is made of the steel material, if the problem in strength is solved, the entire drum 44 is made of the sintered metal. It can also be formed of a friction material. On the other hand, the entire braking inner wall 44a of the drum 44 is made of a sintered metal friction material, but only a part of the braking inner wall 44a of the drum 44 is
It can also be a sintered metal friction material.

Although the braking inner wall 44a of the drum 44 is formed of the sintered metal friction material, the brake shoe 42 may be partially or entirely formed of the sintered metal friction material. Further, the drum 44 and the brake shoe 42
Some or all of them may be formed of a sintered metal friction material.

As the raw material for the sintered metal friction material, alloy powder containing copper as a main component and containing tin, iron, lead, zinc, graphite, silica, etc. was used. May be other than this. Further, as the friction material, a material other than the sintered metal friction material can be used.
Further, the friction material can be formed by other methods such as coating and impregnation without forming by sintering.

Further, neither the drum 44 nor the brake shoe 42 can be constructed so that a friction material is not used. In this case, the drum 44 and the brake shoe 42
Grease can also be injected into the internal space of the roller brake to prevent the seizure of and.

Although the roller 38 is used as the rolling element in the above-described embodiment, a ball, a barrel-shaped rolling element, a tapered rolling element or the like may be used as the rolling element.

Further, as the friction body, the brake shoe 42 whose circumference is divided into three is used, but the friction body is not limited to this. For example, a friction body divided into two or four or more can be used.

In each of the above-mentioned embodiments, the leaf spring 50 formed in a V shape is used as the elastic body.
As the elastic body, for example, a wire spring, a coil spring, or the like formed in a V shape can be used. Further, elastic synthetic resin, rubber or the like may be used.

Although the shoe stopper 46 is provided with the spring abutting portion 46a, the shoe stopper and the spring abutting portion may be provided separately.

Further, although the elastic member is arranged between the spring contact portion provided on the fixing member and the brake shoe 42, a tension coil spring or the like is interposed between the adjacent brake shoes 42. You can also do it.

In each of the above embodiments, the case where the present invention is applied to the rear wheel of the bicycle has been described as an example.
The present invention can also be applied to the front wheels of a bicycle. In addition to bicycles, the invention can be applied to general vehicles such as motorcycles and automobiles.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a roller brake according to an embodiment of the present invention viewed from V1 in FIG.

FIG. 2 is a half cross-sectional view of a hub portion of a rear wheel of a bicycle using a roller brake according to an embodiment of the present invention, as viewed from the rear of the bicycle.

FIG. 3 is a diagram showing a mechanical relationship in a braking operation of the roller brake according to the embodiment of the present invention.

FIG. 4 is a view showing a part of the structure of a roller brake according to another embodiment of the present invention.

FIG. 5 is a view showing the configuration and operation of a conventional roller brake.

[Explanation of symbols]

 32 ... Drive cam 32a ... Cam surface 38 ... Roller 42 ... Brake shoe 42c ... Spring seat 42e ... Notch 44 ... Drum 46 ... Shoe stopper 46a ... Spring contact part 50 ... .... Flat springs

Claims (4)

[Claims] A braking member fixedly provided to a vehicle and rotatably supported by the fixing member, and having a substantially cylindrical braking inner wall centered on a rotation axis with respect to the fixing member. A plurality of brake members are arranged inside the braking inner wall on substantially the same circumference around the rotation axis, and are supported by the fixed member so as to be non-rotatable and movable in the radial direction of the rotation shaft. A friction member having a friction surface capable of contacting the braking inner wall and a pressing surface provided on the back side of the friction surface, on the substantially same circumference around the rotation axis inside the pressing surface of the friction member. A plurality of rolling elements that can press a pressing surface, are disposed inside the rolling elements, are rotatably supported by a fixed member, and move the rolling elements in the radial direction of the rotation shaft with the rotation. A vehicle body having a cam body having a cam surface An elastic body is interposed between the fixed member and the friction body or between the friction bodies, and the friction body is urged so that the braking inner wall of the braking body and the friction surface of the friction body are separated from each other. Brake for vehicles. 2. The vehicle brake according to claim 1, wherein a spring seat displaced toward the pressing surface with respect to the friction surface is provided on the friction surface side of the friction body, and a position of the fixing member facing the spring seat of the friction body. A spring contact portion is provided on the, and an elastic body that urges the friction body in the same direction as the direction in which the friction body is separated from the braking body is arranged between the spring seat of the friction body and the spring contact portion of the fixing member. What you have done is characterized by. 3. The vehicle brake according to claim 2, wherein the spring seat is provided substantially at the center of the friction body. 4. The vehicle brake according to claim 2 or 3, wherein the friction body rotation prevention is fixedly arranged inside the braking inner wall of the braking body with respect to the fixing member and prevents rotation of the friction body. In addition to the provision of one piece, the friction body rotation prevention piece is provided with a spring contact portion.