JPH10148232A - Drum brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake drum which can prevent a brake noise based on a torsional vibration mode, though weight is lightened. SOLUTION: In a peripheral surface of a drum part 12 of a brake drum 10, along a node circle 15 of diametric direction vibration, rib parts 16 having a prescribed axial direction width are partly arranged. In the rib part 16, based on torsional vibration of the drum part 12, parts tending to vibrate by a reverse phase in axial direction both sides of the node circle 15 are locked by each other, so as to prevent a brake noise. In the rib part 16, by not extending the axial direction width to a flange part 11 and a hoop part 13, a material consumption amount is decreased, a weight increase in the brake drum 10 is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum brake capable of preventing vibration during braking and noise from braking.

[0002]

2. Description of the Related Art A drum brake shown in FIG. 1 is a drum brake according to the present invention.
Since there is basically no difference from the conventional drum brake, the basic structure of the conventional drum brake will be described with reference to FIG. That is, the drum brake 1 generally includes a pair of brake shoes 3 and 4 provided at a position supported by the fixed member 2 and opposed to the inner peripheral surface of the brake drum. Return means 5 such as a spring for urging in a direction away from the brake means, and brake shoes 3, 4 provided on the fixed member 2 and against the force of the return means 5.
Is provided with an operating mechanism 6 that presses the brake drum against the brake drum. By the operation of the operation mechanism 6, the brake shoes 3, 4
Is pressed against the inner peripheral surface of the brake drum against the force of the return means 5, braking is applied to the rotating member 7 to which the brake drum is attached. The drag force from the brake drum acting on the brake shoes 3 and 4 is supported by the fixing member 2 by the anchor 8. When the drum brake 1 is applied to a vehicle, the fixing member 2 is a backing plate attached to a steering knuckle 9, the rotating member 7 is a wheel, and the operating mechanism 6 is a wheel cylinder. Various types of drum brakes have been considered depending on whether the operating mechanism 6 and the anchor 8 are floatingly supported or fixedly supported on the fixed member 2.

The brake drum 10 shown in FIG.
Basically, the conventional brake drum is followed, so that the basic structure of the conventional brake drum will be described with reference to FIG. 1. Connected
A cylindrical drum portion 12 having an inner peripheral surface having a cylindrical inner surface frictionally engaged with the friction linings of the brake shoes 3 and 4, and a thickened reinforcing portion on the opening side of the drum portion 12.
3 is provided. Reference numeral 14 denotes a bolt for attaching the brake drum 10 to a wheel.

In a drum brake, brake squeal sometimes occurs during braking due to the friction characteristics of a brake lining and the rigidity of a brake shoe. In particular, in the case of a brake used in a vehicle, the brake squeal causes discomfort to a driver of the vehicle and people around the vehicle.

[0005] The vibration mode of the brake drum includes a plurality of modes from a low-order mode having a small number of vibration nodes (hence, antinodes) to a high-order mode having a large number of vibration nodes.
On the other hand, in terms of the vibration type, there are a mode due to bending and a mode due to torsion. In general, depending on the rotational speed of the brake drum and the frictional engagement between the brake lining and the inner peripheral surface of the drum, a plurality of modes having different orders or different types appear alone or in combination. The vibration mode of the brake drum and the vibration mode of the brake shoe correspond well in terms of vibration order and vibration type, and when they are in resonance with each other, strong vibration and large brake squeal are generated.

An example of a conventional vibration mode involving torsion generated in the brake drum 20 will be described. In FIG. 3, the upper side of the brake drum 20 is the opening side, and the lower side is the flange side. As shown in FIG. 3, when viewed along the circumferential direction of the brake drum 20, there is a radial vibration pattern in which antinodes 21 having a maximum amplitude and nodes 22 that do not vibrate alternately appear. The node 22 is parallel to the axial direction of the brake drum 20. This vibration mode is a torsional vibration mode in which vibrations that are not uniform in the axial direction of the brake drum 20 but are displaced in the radial direction at substantially the center of the drum portion of the brake drum 20 are in opposite phases. That is, a circular node 23 (hereinafter, referred to as a node circle) in which almost no vibration appears can be drawn substantially at the center of the brake drum 20 in the axial direction. In this vibration mode, as shown by a region A, when the displacement that enters the radially inner side is performed on the opening side which is one side of the node circle 23, as shown by a region B, the other side of the node circle 23 On a certain flange side, there is a displacement outward in the radial direction. Brake drum 20
It is known that when the vehicle vibrates in the torsional vibration mode, the brake shoes 3 and 4 match well with the vibration in the torsional mode.

Conventionally, as a brake drum having an outer peripheral portion provided with measures against vibration of the brake drum and brake squeal, for example, Japanese Unexamined Utility Model Publication No. 58-142429 and Japanese Unexamined Patent Application Publication No.
There is one disclosed in Japanese Patent No. 208329. The brake drum disclosed in the former publication has a connection wall that integrally connects a drum portion with which a brake shoe slides and a hub mounting wall portion (or a flange portion) mounted on a hub, and is connected to the drum portion. At least a portion of the wall corresponding to the hub fastening bolt hole of the connection wall is formed thick.

Further, the brake drum disclosed in the latter has a plurality of cooling fins extending in the axial direction on the outer peripheral portion and spaced apart from each other in the circumferential direction. Are different for at least one of the pitches. In the brake drum having such a structure, vibration resonance points are dispersed, and an orderly vibration mode is hardly generated.

[0009]

However, none of the publications disclosed in the two publications take into account the torsional vibration mode as shown in FIG. 3 as the vibration mode of the brake drum. Also, forming a rib extending over the entire width of the brake drum in the axial direction on the outer peripheral surface of the brake drum uses a lot of material for the rib and increases the weight of the brake drum. Therefore, there is a need for a brake drum that can prevent brake squeal based on the torsional vibration mode while saving the amount of material used and being lightweight.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problem, and even if the brake drum tries to vibrate in the torsional vibration mode, the phases are reversed on both axial sides of the nodal circle. An object of the present invention is to provide a lightweight drum brake capable of preventing brake squeal by integrally restraining portions to be vibrated by ribs.

The present invention has been made in order to solve the above-mentioned object.
It is configured as follows. That is, the present invention provides a brake drum provided on a rotating member, a brake shoe supported by a fixed member and provided at a position opposed to an inner circumferential surface of the brake drum, and a brake shoe provided on the inner circumferential surface of the brake drum. Return means for urging in a direction away from the
An operating mechanism provided on the fixing member and pressing the brake shoe against the brake drum against the force of the return means, wherein the brake drum is fixed to the rotating member by a flange portion; A drum portion having a peripheral surface and a hoop portion formed on the opening side of the drum portion,
The present invention relates to a drum brake having a rib portion having a predetermined axial width along a nodal circle of radial vibration generated in the drum portion on an outer peripheral surface of the drum portion.

Since the present invention is configured as described above, it operates as follows. That is, in the drum break according to the present invention, the rib portion having a predetermined axial width along the nodal circle of the radial vibration generated in the drum portion generates the opposite-phase vibration mode on both sides of the nodal circle. This prevents the occurrence of a torsional vibration mode as shown in FIG. Further, since the width of the rib does not need to be large enough to extend to the flange or the flank, the consumption of the material required for forming the rib is reduced, and the weight of the brake drum is less increased.

The rib portion may be formed on the entire circumference along the node circle, or may be formed partially along the node circle. Even if it is partially formed, it is possible to sufficiently suppress the radial vibration in the opposite phase across the node circle.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view showing a drum brake according to the present invention. The basic structure of the brake drum 10 and the configuration including the brake shoes 3 and 4 and the operating mechanism 6 are the same as those described in the related art, so that the description will not be repeated.

The drum section 12 of the brake drum 10 includes
A rib portion 16 having a predetermined width is formed partially along a node circle 15 (shown by a dotted line). The width of the rib portion 16 is a short width that does not extend to the flange portion 11 and the flank portion 13, and the consumption of material is small. Rib 16
Functions to prevent the drum portion 12 of the brake drum 10 from oscillating in opposite phases on both sides of the node circle 15, and prevents brake squeal based on this oscillation mode.

FIG. 2 is a perspective view showing another embodiment of the drum brake according to the present invention. In FIG. 2, since the members on the fixed side, such as the brake shoe and the operating mechanism, are the same as those in the example shown in FIG. 1, the description thereof is omitted, and only the brake drum 17 is shown. Also, the brake drum 1
The basic structure of the drum section 12 and the like is the same as the structure of the brake drum 10 in the embodiment shown in FIG. In the brake drum 17 shown in FIG. 2, a rib portion 18 is formed on the outer peripheral surface of the drum portion 12 along the entire circumference along a circle (not shown) corresponding to the node circle 15 shown in FIG. I have. The width of the rib portion 18 is a predetermined width that does not extend to the flange portion 11 or the flank portion 13. The mechanism of the function of the rib portion 18 is the same as that of the rib portion 16 shown in FIG. 1, but the function of suppressing the vibration mode shown in FIG.

[0017]

Since the present invention is configured as described above, it has the following effects. That is, in the drum break according to the present invention, the rib portion having a predetermined axial width along the nodal circle of the radial vibration generated in the drum portion generates the anti-phase radial vibration on both sides of the nodal circle. A torsional vibration mode is prevented from occurring, and brake squeal based on the vibration mode is prevented. When this drum brake is applied to a vehicle, it does not cause discomfort to a driver or a person near the vehicle. Also, since the width of the rib does not need to be large enough to extend to the flange or the flank, the consumption of the material required for forming the rib is reduced, the increase in manufacturing cost is suppressed, and the The increase in the weight of the drum is reduced, and the increase in fuel efficiency is also suppressed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a drum brake according to the present invention.

FIG. 2 is a perspective view showing another embodiment of the drum brake according to the present invention, showing only the brake drum.

FIG. 3 is an explanatory diagram of one vibration mode with torsion occurring in a conventional brake drum.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drum brake 2 Backing plate (fixing member) 3, 4 Brake shoe 5 Return means 6 Operating mechanism 7 Rotating member 10 Brake drum 11 Flange part 12 Drum part 13 Hoop part 15 Sectional circle 16 Rib part 17 Brake drum 18 Rib part

Claims (2)

[Claims] 1. A brake drum provided on a rotating member,
A brake shoe supported by a fixing member and provided at a position facing the inner peripheral surface of the brake drum, a return unit for urging the brake shoe in a direction away from the inner peripheral surface of the brake drum, and the fixing member. An actuating mechanism that is provided and presses the brake shoe against the brake drum against the force of the return means, wherein the brake drum includes a flange fixed to the rotating member and the inner peripheral surface. A drum portion and a hoop portion formed on the opening side of the drum portion, and an outer circumferential surface of the drum portion has a predetermined axial direction along a nodal circle of radial vibration generated in the drum portion. A drum brake comprising a rib having a width. 2. The drum brake according to claim 1, wherein the rib portion is formed entirely or partially along the nodal circle.