JPH09166166A - Drum type brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the generation of brake noise by improving the vibration characteristics of a brake drum. SOLUTION: Four groove forming parts 11 having a groove long in a direction extending along a rotary central axis and short in a peripheral direction are integrally formed in the outer peripheral surface 1d of a brake drum 1. A damping member 10 formed of a rubbery elastic substance is pressed and held in the groove of the groove forming part 11 in such a state to protrude from the surface of the groove forming part 11. The four groove forming parts 11 are uneven in a distance in a peripheral direction. Thus, the disposing positions in a peripheral direction of four damping members 10 are also unevert. Further, the outer surface side of each damping member 10 makes contact with the inner peripheral surface of a wheel disc. Namely, each damping member 10 is located between the outer peripheral surface 1d of the brake drum 1 and the inner peripheral surface of the wheel disc of a road wheel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum type brake, and more particularly to a drum type brake capable of improving vibration characteristics of a brake drum and reducing so-called brake squeal.

[0002]

2. Description of the Related Art A drum-type brake, which is one of conventional braking devices, is constructed as shown in FIG. 15 and has an inner peripheral surface 1a of a substantially cylindrical brake drum 1 which rotates integrally with wheels.
This is a device that performs braking by using the frictional force when the lining 2a of the brake shoe 2 having a substantially arc shape supported by the vehicle body such as a member is brought into contact. Specifically, this drum brake has a back plate 3 fixed to the vehicle body side, and a braking torque is applied to the back plate 3 so as to be located inside the inner peripheral surface 1a of the brake drum 1. The receiving anchor 4 is fixed, and one end side of the pair of brake shoes 2 facing each other is swingably attached to the anchor 4. Each of the pair of brake shoes 2 is arranged along the inner peripheral surface 1a of the brake drum 1, and when not braking, the lining 2a fixed to the outer peripheral surfaces thereof has a predetermined distance from the inner peripheral surface 1a. They are facing each other.

A wheel cylinder 5 and a return spring 6 are disposed between the ends of the pair of brake shoes 2 opposite to each other at the positions opposite to the anchor 4 side. Is supplied, a pair of pistons 5A provided to be able to move back and forth in the left-right direction,
5B is displaced in the extending direction, whereby the end portion of the brake shoe 2 opens left and right and is pressed toward the inner peripheral surface 1a,
The lining 2a is pressed against and brought into contact with the inner peripheral surface 1a, and the rotational force of the brake drum 1 is converted into frictional heat at the contact portion to perform braking.

In such a drum brake,
When the lining 2a comes into contact with the inner peripheral surface 1a of the brake drum 1 to generate frictional heat, the frictional vibration generated on those frictional surfaces vibrates the brake drum 1 and excites the natural vibration of the brake drum 1. May cause unpleasant brake squeal. Here, an object such as a cylindrical body or a disc having the same thickness as the general brake drum 1 shown in FIG. 15 has a bending vibration at its outer peripheral portion, for example, a two-node diameter mode (see FIG. 16A). ), Diameter three-bar mode (Fig. 16
(See (b)), Diameter 4-node mode (see FIG. 16 (c)),
There are eigenmodes exhibiting vibration modes such as the 5-node diameter mode (see FIG. 16D) and the 6-node diameter mode (see FIG. 16E). The eigenmodes are such that the brake drum 1 rotates central axis ( In FIG. 15, since it is an object having symmetry about an axis extending through the center of the brake drum 1 and extending in the direction orthogonal to the drawing, it becomes a heavy root. Note that "there is a double root" means not only one eigenmode as shown in FIGS. 16A to 16D but also another eigenmode of the same shape whose phase is shifted by a half cycle in the circumferential direction. That is, they are considered to exist at the same frequency.

That is, when the peripheral surface of the brake drum 1 is vibrated while the brake drum 1 is stationary, the brake drum 1 is symmetric about the center axis of rotation regardless of which position in the circumferential direction is the vibration point. Since it is a certain object, a response mode in which its excitation point is always antinode appears, so it seems that the brake drum 1 has many eigenmodes.
Considering the axis along the diameter as indicated by the chain line in 6 (a) to 6 (d), it can be considered that the axis is rotating with respect to the brake drum 1. Then, vibrationally,
It can be considered that there are two eigenmodes, that is, an eigenmode as shown in FIGS. 16A to 16D and an eigenmode having the same shape that is deviated from this by a half cycle. is there.

In such a diameter node mode, the lining 2a of the brake shoe 2 and the inner peripheral surface 1a of the brake drum 1 are used.
Since the amplitude of vibration on the contact surface with
The diametral node mode is easily excited by the frictional vibration generated between the a and the lining 2a, which often causes the brake squeal. As a conventional technique focusing on such a phenomenon, there is one disclosed in Japanese Utility Model Laid-Open No. 59-177834. That is, the conventional technique is characterized in that a damping material (damping member) such as rubber is interposed between the outer peripheral surface of the brake drum and the disc wheel to which the brake drum is fixed, By interposing such a damping member, it is possible to suppress the diameter node mode as shown in FIGS. 16 (a) to 16 (e), so that the acoustic radiation efficiency is reduced and the brake squeal is suppressed. Met.

[0007]

Certainly, if the structure disclosed in the above publication is adopted, for example, as shown in FIG. 17, four damping members are provided on the outer peripheral surface of the brake drum 1 at equal intervals in the circumferential direction. By arranging ten, a sufficient damping effect can be expected with respect to the three-node mode, the five-node mode, etc., so it is possible to suppress the brake squeal to some extent, but the number of damping members 10 to be arranged Therefore, there is a problem in that the undesired squealing of the brakes may still occur because the diametral node mode capable of damping is determined.

Here, a case will be described in which four damping members 10 are provided at equal intervals as shown in FIG. 17 based on the conventional technique described in the above publication. That is, considering the two-node diameter mode and the four-node diameter mode in the configuration of FIG. 17, as shown in FIG. 18, the attachment portion of the damping member 10 is located at the antinode position with respect to one eigenmode of the heavy roots. Therefore, a large damping effect can be expected, but the vibration damping effect cannot be expected at all because it hits the position of the node with respect to the other one eigenmode. It is called mode.).

When this effect is confirmed by the finite element method,
As shown in FIG. That is, FIG. 19 shows a case where the position where the damping member 10 is attached (point A in FIG. 17) is excited and a position where the damping member 10 is not attached (B in FIG. 17).
8 shows the relationship between the vibration frequency and the vibration point compliance (compliance means displacement / load) when the point) is vibrated. It can be seen from FIG. 19 that a large vibration level does not reach when the point A is excited, but a large peak appears in the vibration level when the point B is excited. The reason is that, when point A is excited, only one eigenmode (left side in FIG. 18) that can be damped by the damping member 10 is excited, and the other eigenmode (right side in FIG. 18) has a vibration point. However, when the point B is excited, the position of the damping member 10 hits the node of the eigenmode and the undamped eigenmode (right side in FIG. 18) is excited. Is.

Generally, when a plurality of damping members 10 are arranged on the outer peripheral surface of the brake drum 1 at regular intervals in the circumferential direction, as shown in Table 1 below, when the number N of damping members 10 is an even number, In the diametral node mode that is a multiple of N / 2, and when the number N is an odd number, in the diametral node mode that is a multiple of N, one of the roots becomes an undamped eigenmode, and a sufficient damping effect cannot be obtained. In Table 1, the angle θ (degrees) is the arrangement angle (arrangement interval) of the damping member 10, the symbol ◯ means that there is a damping effect, and the symbol x means that there is no damping effect.

[0011]

[Table 1]

In an actual drum type brake as shown in FIG. 15, the inner peripheral surface 1a of the brake drum 1 is affected by a difference in operating conditions such as an operating oil pressure of the wheel cylinder 5 and a change with time of the lining 2a. Since the frequency component of the frictional vibration generated between the lining 2a and the lining 2a changes, how can the vibration be reduced for the diameter node mode of a specific order as in the prior art described in the above publications and papers? Even in such a situation, the brake squeal cannot be reduced sufficiently.

The present invention has been made by paying attention to the unsolved problems of the prior art as described above, and by simultaneously damping a plurality of diametral node modes which are the roots,
An object of the present invention is to provide a drum brake that improves the vibration characteristics of the brake drum and can more reliably suppress brake squeal.

[0014]

In order to achieve the above object, the invention according to claim 1 is a drum type brake having a brake drum that rotates integrally with a wheel, the outer peripheral surface or the bottom portion of the brake drum. A plurality of damping members are interposed between the outer surface and the road wheel composed of the wheel rim and the wheel disc, and the circumferential intervals of the plurality of damping members are made uneven.

In order to achieve the above object, the invention according to claim 2 is a drum type brake having a brake drum that rotates integrally with a wheel, the outer peripheral surface or the bottom outer surface of the brake drum, and A plurality of N (N is an even number) damping members are interposed between the rim of the wheel and the road wheel including the wheel disc, and the plurality of damping members are N / 2 damping members as constituent elements. The damping members that are divided into two groups are arranged at equal intervals in the circumferential direction, and the relative angle α between the two groups is 0.36 × (90 / N) degrees <α <1.64 x (90 /
The range was set to N) degrees.

In order to achieve the above object, the invention according to claim 3 is a drum type brake having a brake drum that rotates integrally with a wheel, wherein the outer peripheral surface or the bottom outer surface of the brake drum, A plurality of N damping members are provided at equal intervals in the circumferential direction between the wheel rim and the road wheel composed of a wheel disc, and when the N is an even number, M = N / 2, When M = N when N is an odd number, the circumferential width of each damping member is set to an angle of 0.29 × (180 / M) degrees or more.

Further, the invention according to claim 4 is the drum type brake according to any one of claims 1 to 3, wherein:
While disposing an annular member coaxially with the brake drum so as to face the outer peripheral surface or the bottom outer surface thereof, the damping member, the outer peripheral surface or the bottom outer surface of the brake drum,
It was interposed between the annular member. That is, in the invention according to Claim 4, the invention according to Claims 1 to 3, except that the damping member is interposed between the brake drum and the annular member, not between the brake drum and the road wheel. Is the same as.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 are views showing a first embodiment of the present invention. Since the overall structure of the drum brake is the same as the conventional structure shown in FIG. 15, its illustration and description are omitted.

First, the structure will be described. As shown in FIG. 1 which is a perspective view of the brake drum 1 of this embodiment,
The bottom part is formed in a substantially cylindrical shape, and one end thereof (the side facing right in FIG. 1) is closed except for the central through hole 1b and a plurality of bolt holes 1c used when mounting on the wheel side. 1e, the other end is open, and the back plate 3 having the brake shoe and the wheel cylinder as shown in FIG. 15 attached thereto and supported on the vehicle body side is provided inside the cylindrical shape. It is arranged.

On the outer peripheral surface 1d of the brake drum 1, four grooves are formed which are long in the direction along the rotation center axis of the brake drum 1 (the axis passing through the center of the cylindrical shape) and short in the circumferential direction. The portion 11 is integrally formed, and the damping member 10 made of a rubber-like elastic body is press-fitted and held in the groove of each groove forming portion 11 so as to project from the surface of the groove forming portion 11.

The four groove forming portions 11 are provided in the brake drum 1
As shown in FIG. 2, which is a cross-sectional view of the central portion in the axial direction of FIG. Specifically, the circumferential interval between the groove forming portions 11 is 95 °, 90 °.
The angles are °, 100 °, and 75 °. Therefore, the arrangement positions of the four damping members 10 in the circumferential direction are also non-uniform.
FIG. 3 is a vertical cross-sectional view (upper half) in a state where the brake drum 1 is attached to a wheel. The brake drum 1 is integrated with a road wheel 12 including a rim 12A and a wheel disc 12B via a hub bolt 13a. Hub 13
The brake drum 1 is thereby rotated integrally with the wheels. The rim 12
A tire (not shown) is held on the outer peripheral surface of A, and the tire and the road wheel 12 form a wheel. Further, the hub 13 is rotatably held by an axle housing 15 via a bearing 14, and the back plate 3 is fixed to the axle housing 15.

The outer surface of each damping member 10 fixed to the outer peripheral surface 1d of the brake drum 1 is in contact with the inner peripheral surface of the wheel disk 12B. That is, each damping member 10 is interposed between the outer peripheral surface 1d of the brake drum 1 and the inner peripheral surface of the wheel disc 12B of the road wheel 12. Next, the function and effect of this embodiment will be described.

That is, when the four damping members 10 are interposed between the outer peripheral surface 1d of the brake drum 1 and the inner peripheral surface of the wheel disc 12B as in the present embodiment, a non-damped eigenmode can be achieved. It is the two-node diameter mode that is effective. However, since the four damping members 10 are not arranged at equal intervals in the circumferential direction but are arranged at uneven intervals, all the damping members 10 are positioned at the nodes of the vibration mode ( The situation on the right side of FIG. 18) does not occur.
That is, in this embodiment, there is no non-damped eigenmode.

FIG. 4 shows the damping member 1 according to the present embodiment.
When the position where 0 is attached (point A in FIG. 2) is vibrated,
A position where the damping member 10 is not attached (for example, B in FIG. 2).
The relationship between the excitation frequency and the compliance of the excitation point is shown in the case where the point) is excited. According to FIG. 4, a large vibration level is obtained regardless of whether the point A or the point B is excited. It turns out that it does not reach. The reason is that when point A is excited, only one eigenmode (left side in FIG. 18) that can be damped by the damping member 10 is excited as in the conventional case, and the other eigenmode (right side in FIG. 18) is excited. Since the vibration point is a node, it is not excited, and even when the point B is excited, there is no undamped eigenmode, so the damping member 10
This is because the damping effect of is exerted and the damping effect is obtained.

That is, in the present embodiment, even though the number of the damping members 10 is four, since the damping members 10 are arranged at non-uniform intervals in the circumferential direction, the non-damping eigenmode does not exist. Therefore, a diameter node mode that is a multiple of 2 (diameter 2
The damping effect can also be obtained for the knot mode, the 4-knot mode, the 6-knot mode, and so on. Therefore, the frequency component of the frictional vibration generated between the inner peripheral surface 1a of the brake drum 1 and the lining changes due to the difference in the operating conditions such as the hydraulic pressure of the wheel cylinders and the change of the lining with time, and the order of the diameter node mode is changed. Even if changes occur, the brake squeal is suppressed and the noise level is reduced.

Although the number of the damping members 10 is four in the present embodiment, the number is not limited to this, and may be three or five or more, for example. Even when the number of the damping members 10 is other than 4, if the circumferential intervals of the damping members 10 are made non-uniform, the non-damping eigenmode does not exist. Even if the diameter node mode marked with appears, it becomes possible to suppress the brake squeal and reduce the noise level.

5 to 8 are views showing a second embodiment of the present invention. The same components as those in the first embodiment are designated by the same reference numerals, and the duplicated description will be omitted. First, the configuration will be described. In the present embodiment, the outer peripheral surface 1d of the brake drum 1 has 90 circumferentially equidistant intervals.
A total of eight groove forming portions 11A and 11B are formed, that is, four groove forming portions 11A that are separated by 90 degrees and four groove forming portions 11B that are also separated by 90 degrees at equal intervals in the circumferential direction. The damping member 10 is press-fitted and held in the forming portions 11A and 11B.

That is, a total of eight groove forming portions 1 for press-fitting and holding the damping member 10 are provided on the outer peripheral surface 1d of the brake drum 1.
1A and 11B are formed, and the eight groove forming portions 11A and 11B can be divided into two groups each having four elements as constituent elements, and the groove forming portions 11A and 11B forming each group are peripheral. They are arranged at regular intervals of 90 ° in each direction.

In the present embodiment, the groove forming portion 11
The relative angle α between the group A and the groove forming portion 11B is set to 22.5 °. Other configurations are similar to those of the first embodiment. Next, the function and effect of this embodiment will be described. That is, when focusing on the four damping members 10 held in the groove forming portion 11A of one group, the non-damping eigenmode may be the two-node diameter mode. In addition, since the four damping members 10 held in the groove forming portions 11B of the other group are provided at a distance from each other in the circumferential direction by the angle α, the non-damping eigenmode of the two-node diameter mode is The four damping members 10 held in the groove forming portion 11B enable damping. That is, the non-damped eigenmodes of the four damping members 10 forming one group are
Damped by the four damping members 10 of the other group, and conversely, the undamped eigenmodes of the four damping members 10 of the other group are damped by the four damping members 10 of the one group. It is.

FIG. 7 shows the damping member 1 according to the present embodiment.
When the position where 0 is attached (point A in FIG. 2) is vibrated,
A position where the damping member 10 is not attached (for example, B in FIG. 2).
The relationship between the excitation frequency and the compliance of the excitation point is shown in the case where the point) is excited. According to FIG. 7, a large vibration level is obtained regardless of whether the point A or the point B is excited. It turns out that it does not reach. The reason is that when the point A is excited, only one eigenmode (left side in FIG. 18) that can be damped by the damping member 10 is excited and the other eigenmode (right side in FIG. 18) is excited as in the conventional case. Since the vibration point is a node, it is not excited, and even when the point B is excited, as described above, the damping members 10 of the two groups cancel out the undamped eigenmodes of the other group, so that the damping This is because the damping effect of the member 10 is always exerted and the damping effect is obtained.

In other words, at any position of the excitation point, the damping member 10 forming at least one group.
Will be located at the antinode of the vibration mode, and therefore, for the diameter node mode of multiples of 4 (diameter 4-node mode, 8-node mode, 12-node mode, ...) Which is a problem when there are eight damping members 10. Also has a damping effect. Therefore, similar to the first embodiment, due to the difference in operating conditions such as the hydraulic pressure of the wheel cylinders and the change with time of the lining,
Even if the frequency component of the frictional vibration generated between the inner peripheral surface 1a of the brake drum 1 and the lining changes and the order of the diameter node mode changes, the brake squeal is suppressed and the noise level is reduced. .

Although the number of the damping members 10 is 8 in the present embodiment, the number is not limited to this, and if the number is even, for example, 6 or less or 10 or less.
It may be the above. Then, the number of damping members 10 is set to 8
In other cases, if the damping members 10 are divided into two groups, the damping members 10 in each group are arranged at equal intervals, and the relative angle α between the groups is set appropriately, Since the non-damped eigenmode does not exist, it is possible to suppress the brake squeal and reduce the noise level even if the diameter node mode marked with X in Table 1 appears.

Here, in the configuration of the present embodiment, when the relative angle α between the two groups is used as a variable, the transition of the maximum peak level of vibration is calculated by focusing on only the diameter node mode. As shown in FIG. 8, it was found that when the angle α is 16 ° or more and 74 ° or less, a sufficient vibration reducing effect (the effect that the maximum peak level can be suppressed to 6 dB or less) can be obtained. Therefore, if the angle α at which a sufficient vibration reduction effect is obtained is generalized with the total number of damping members 10 being N, 0.36 × (90 / N) degrees <α <1.64 × (90 /
It was confirmed by an experiment by the present inventors that the degree of N is N degrees. That is, when the total number N (N is an even number) of the damping members 10 are arranged on the outer peripheral surface of the brake drum 1, the damping members 1 are arranged.
0 is divided into two groups of N / 2 each, and the damping members 10 forming each group are arranged at equal intervals.
If the relative angle α between the two groups is set within the range shown in the above equation, the same effect as that of the second embodiment can be obtained.

9 to 12 are views showing a third embodiment of the present invention. It should be noted that the same components as those in the above-described respective embodiments are denoted by the same reference numerals, and the duplicate description thereof will be omitted.
First, the configuration will be described. In this embodiment, four groove forming portions 11 are formed on the outer peripheral surface 1d of the brake drum 1 as in the first embodiment, and each groove forming portion 11 is formed.
The damping member 10 is press-fitted and held in the. However, in the present embodiment, the groove forming portions 11 are arranged at equal intervals in the circumferential direction.
The damping members 10 are arranged apart from each other by a degree, and the width (width in the circumferential direction) of the damping member 10 is wider than that in the case of the first embodiment. Here, if the width of each damping member 10 is represented by an angle β, the angle β is set to 26 ° or more in the present embodiment.

The other structure is the same as that of the first embodiment. Next, the function and effect of this embodiment will be described. That is, in the present embodiment, since four damping members 10 are provided, the non-damping eigenmode may be the two-node diameter mode, but the angle β in the width direction of each damping member 10 is 26. Since the damping member 10 is set to be equal to or more than 0 °, each damping member 10 is not located only in one of the two eigenmodes of the two-node diameter mode, and the center portion in the width direction of the damping member 10 is assumed to be one eigenmode node. Even if located, the damping member 10
The end in the width direction of is always located at the antinode of the other eigenmode. That is, as a result of making the width of the damping member 10 sufficiently wide, there is no undamped eigenmode.

FIG. 11 shows a case where the position where the damping member 10 is attached (point A in FIG. 10) is vibrated and a position where the damping member 10 is not attached (for example, FIG.
FIG. 11 shows the relationship between the excitation frequency and the excitation point compliance in the case where the B point of 0) is excited, but according to this FIG. 11, both of the A point and the B point are excited. It turns out that it does not reach a large vibration level. The reason for this is that when point A is vibrated, the damping member 10
Only one eigenmode (left side in FIG. 18) that can be damped by is excited, and the other eigenmode (right side in FIG. 18) is not excited because the vibration point is a node. However, as described above, the widthwise end portion of the damping member 10 enters the antinode position of the mode in which the non-damping eigenmode can occur, and the damping effect is exhibited to obtain the damping effect.

In other words, at any position of the excitation point, at least a part of the damping member 10 always exists at the antinode position of the eigenmode. The damping effect can be obtained even for the diameter node mode of multiples of 2 (diameter 2-node mode, 4-node mode, 6-node mode, ...). Therefore, the first
In the same manner as in the above embodiment, the frequency component of the frictional vibration generated between the inner peripheral surface 1a of the brake drum 1 and the lining changes due to the difference in the operating conditions such as the hydraulic pressure of the wheel cylinders and the temporal change of the lining. Even if the order of the diameter node mode changes, the brake squeal is suppressed and the noise level is reduced.

Although the number of the damping members 10 is four in the present embodiment, the number is not limited to this, and may be three or less or five or more, for example. Then, even when the number of the damping members 10 is other than 4, if the angle β in the width direction of the damping members 10 is made sufficiently large, the undamped eigenmode does not exist.
Even if the diameter node mode marked with X appears, it is possible to suppress the brake squeal and reduce the noise level.

Here, in the case where four damping members 10 are arranged at equal intervals in the circumferential direction as in this embodiment, the angle β in the width direction of each damping member 10 is used as a variable and only in the diameter node mode. When the transition of the maximum peak level of vibration was calculated by paying attention, the angle β was 26 ° as shown in FIG.
It was found that a sufficient vibration reduction effect (effect that the maximum peak level can be suppressed to 6 dB or less) can be obtained if the above is satisfied. However, in order to keep the weight and cost of the brake drum 1 constant, the transition of the maximum peak level was calculated under the condition that the total amount of damping of the four damping members 10 was constant.

Further, when the angle β at which a sufficient vibration reducing effect is obtained is generalized with the total number of the damping members 10 being N, the angle of 0.29 × (180 / M) degrees or more is obtained according to the present invention. It was confirmed by the experiment of the researchers. However, when the number N is an even number, M = N / 2, and when the number N is an odd number, M = N. That is, when a number N of damping members 10 are arranged on the outer peripheral surface of the brake drum 1 at equal intervals in the circumferential direction, if the angle β in the width direction of the damping members 10 is set to be the above angle or more, the third The same effect as that of the embodiment can be obtained.

13 and 14 are views showing a fourth embodiment of the present invention. It should be noted that the same components as those in the above-described respective embodiments are denoted by the same reference numerals, and the duplicate description thereof will be omitted. That is, in the present embodiment, the short cylindrical annular member 20 is arranged coaxially with the brake drum 1 so as to surround the outer peripheral surface 1d, and between the outer peripheral surface 1d and the inner peripheral surface of the annular member 20. In addition, eight damping members 10 are interposed. The damping member 10 is press-fitted onto the outer peripheral surface 1d of the brake drum 1 while being bonded to the inner peripheral surface of the annular member 20, so that the outer peripheral surface 1d and the annular member 2 are joined together.
It is arranged between 0s.

The outer diameter of the annular member 20 is determined by the rim 12A of the road wheel 12 surrounding the annular member 20.
It is smaller than the inner diameter of the wheel disc 12B. Therefore, as shown in FIG. 14, the annular member 2
0 is not in contact with the road wheel 12. The circumferential arrangement pattern of the eight damping members 10 is
The arrangement pattern of the damping member 10 in the second embodiment is similar.

Even with such a structure, the damping member 10 interposed between the outer peripheral surface 1d and the annular member 20 has the above second structure.
Since the same effects as those of the damping member 10 according to the second embodiment are exhibited, the same effects as those of the second embodiment can be obtained. Moreover, according to the present embodiment, the damping member 10
Since it is not necessary to perform processing such as forming the groove forming portion 11 on the outer peripheral surface 1d of the brake drum 1 for fixing the vehicle, it is advantageous in terms of cost and can be easily applied to the existing drum brake. There is an advantage.

In the fourth embodiment, eight damping members 10 are provided and the arrangement pattern of the damping members 10 conforms to that of the second embodiment, but is not limited to this. However, the number of the damping members 10 is not limited, and the arrangement pattern of the damping members 10 may be the same as that of the first embodiment or the third embodiment.

In each of the above embodiments, the damping member 1
Although 0 is made of a rubber-like elastic body, it is not limited to this, and may be made of a resin material, or may be made by using solid friction vibration, or the fluid may be an orifice. It may be one that utilizes the attenuation that occurs when passing through. In each of the above embodiments, the damping member 10 is arranged on the outer peripheral surface 1d of the brake drum 1. However, the present invention is not limited to this, and the outer surface of the bottom portion 1e of the brake drum 1 and The damping member 10 may be interposed between the road wheel 12 and the road wheel 12 facing each other.
A thin plate-shaped ring member is disposed so as to face the outer surface of the damping member 1e, and the damping member 1 is provided between the outer surface of the bottom portion 1e and the ring member.
You may make it interpose 0.

[0046]

As described above, according to the present invention,
Since a plurality of damping members are not simply arranged at equal intervals in the circumferential direction but appropriately devised and arranged, it is possible to suppress the diameter node mode, which was not expected to be effective in the past. There is an effect that the noise level can be reduced by suppressing the brake squeal.

In particular, according to the invention of claim 4, in addition to the above effects, machining of the brake drum is not required, which is advantageous in terms of cost, and can be easily applied to the existing drum brake. You can also get the effect.

[Brief description of the drawings]

FIG. 1 is a perspective view of a brake drum according to a first embodiment.

FIG. 2 is a cross-sectional view of a central portion in the axial direction of the brake drum according to the first embodiment.

FIG. 3 is a cross-sectional view of the drum brake in which the brake drum of the first embodiment is incorporated.

FIG. 4 is a graph showing a vibration characteristic of the brake drum of the first embodiment.

FIG. 5 is a perspective view of a brake drum according to a second embodiment.

FIG. 6 is a cross-sectional view of a brake drum according to a second embodiment at a central portion in an axial direction.

FIG. 7 is a graph showing vibration characteristics of the brake drum of the second embodiment.

FIG. 8 is a graph showing the relationship between the angle α and the maximum peak level according to the second embodiment.

FIG. 9 is a perspective view of a brake drum according to a third embodiment.

FIG. 10 is a sectional view of a brake drum according to a third embodiment at a central portion in an axial direction.

FIG. 11 is a graph showing vibration characteristics of the brake drum of the third embodiment.

FIG. 12 is a graph showing the relationship between the angle β and the maximum peak level in the third embodiment.

FIG. 13 is a cross-sectional view of a brake drum according to a fourth embodiment at a central portion in an axial direction.

FIG. 14 is a cross-sectional view of a drum brake in which a brake drum according to a fourth embodiment is incorporated.

FIG. 15 is a cross-sectional view showing a configuration of a general drum type brake.

FIG. 16 is an explanatory diagram of a proper mode of the brake drum.

FIG. 17 is a sectional view of a conventional brake drum at a central portion in the axial direction.

FIG. 18 is a diagram illustrating the operation of a conventional damping member.

FIG. 19 is a graph showing vibration characteristics of a conventional brake drum.

[Explanation of reference symbols] 1 brake drum 1d outer peripheral surface 1e bottom 10 damping member 11, 11A, 11B groove forming portion 12 road wheel 12A rim 12B wheel disc 20 annular member

Claims (4)

[Claims] 1. A drum-type brake having a brake drum that rotates integrally with a wheel, wherein a plurality of drum-type brakes are provided between an outer peripheral surface or a bottom outer surface of the brake drum and a road wheel including a rim of the wheel and a wheel disc. And a plurality of damping members arranged in the circumferential direction in a non-uniform manner. 2. A drum type brake having a brake drum rotating integrally with a wheel, wherein a plurality of drum brakes are provided between an outer peripheral surface or a bottom outer surface of the brake drum and a road wheel including a rim of the wheel and a wheel disc. While interposing N (N is an even number) damping members, the plurality of damping members are divided into two groups having N / 2 damping members as constituent elements, and the damping members forming each group are circumferentially arranged. Direction, and the relative angle α between the two groups is 0.36 × (90 / N) degrees <α <1.64 × (90 /
A drum brake characterized by being set in a range of N) degrees. 3. A drum-type brake having a brake drum that rotates integrally with a wheel, wherein a drum brake is provided between an outer peripheral surface or a bottom outer surface of the brake drum and a road wheel including a rim of the wheel and a wheel disc. A plurality of N damping members are interposed at equal intervals in the direction, and when N is an even number, M = N / 2, N
Is an odd number, when M = N, the circumferential width of each damping member is an angle of 0.29 × (180 / M) degrees or more. 4. An annular member is disposed coaxially with the brake drum so as to face the outer peripheral surface or the bottom outer surface, and the damping member is provided with the outer peripheral surface or the bottom outer surface of the brake drum, and the annular member. The drum type brake according to any one of claims 1 to 3, which is interposed between the brakes.