JP2738234B2 - Brake shoe resonance noise prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing resonance of a brake shoe during braking of a drum brake.

[0002]

2. Description of the Related Art As shown in FIG. 1, a vehicle drum brake includes a brake drum 1 (hereinafter simply referred to as a drum 1) attached to a wheel side and an inner peripheral surface of the drum 1. 1 provided on the fixed side (back plate)
A pair of brake shoes 2 and 2 is provided.

It is well known that when a brake pedal (not shown) is depressed, the brake shoes 2 and 2 are pushed outward and pressed against the inner peripheral surface of the drum 1, and braking is performed by the frictional force. is there. The brake shoe 2 includes an arc-shaped rim 3 adapted to the shape of the inner peripheral surface of the drum 1, and a web 4 fixed perpendicularly to the inner surface of the rim 3, and the outer surface of the rim 3. On the side, a lining 5 is stretched as a friction material.

Therefore, the brake shoe 2
Is spread out and pressed against the drum 1, frictional vibration occurs between the drum 1 and the lining 5, and the brake shoe resonates at a certain frequency. At this time, a resonance sound commonly called squeak is generated. In the drawing, reference numeral 6 denotes an anchor pin of the brake shoe 2, reference numeral 7 denotes a wheel cylinder that pushes and spreads the brake shoe 2 by hydraulic pressure, and reference numeral 8 denotes a return spring of the brake shoe 2.

[0005] Usually, in order to prevent the resonance noise (squeal), squeeze measures such as cutting the end face of the lining 5 or falling off the lining 5 and changing the material of the lining are taken. Further, as disclosed in Japanese Utility Model Laid-Open No. 59-56436, the present applicant spot-welds a plate-shaped mass body to a portion having a large vibration mode amplitude on the back surface of a brake shoe (rim). Has proposed a brake shoe vibration damping device that is fixed.

[0006]

However, the resonance of the brake shoe occurs not only in the rim portion including the lining but also in the web portion, and these cooperate to produce a resonance sound of the entire brake shoe. The conventional measures against the lining and the attachment of the mass body to the rim back alone are not enough to achieve sufficient resonance measures for the entire brake shoe, especially when the mass body is spot-welded to the rim back. There is a problem that the intended purpose cannot be achieved due to the detachment of the welding due to long-term use.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a structure in which a mass body is buried and clamped at a position where the resonance amplitude of the rim and the web is maximized so that the mass body is firmly attached so as not to come off. It is another object of the present invention to provide a brake shoe resonance noise prevention device having a high vibration suppression efficiency adapted to the resonance characteristics of a brake shoe.

[0008]

According to the present invention, there is provided a device for preventing resonance of a brake shoe according to the first aspect of the present invention, comprising a brake comprising an arc-shaped rim and a web fixed perpendicularly to the inner surface of the rim. In the shoe, a mass body is buried inside the rim at a portion where the resonance amplitude of the rim increases, and the mass body is sandwiched between both surfaces of the web at a portion where the resonance amplitude of the web increases. It is characterized by:

According to a second aspect of the present invention, there is provided an apparatus for preventing resonance of a brake shoe, wherein a mass body embedded inside the rim is sandwiched between the rim and a lining adhered to a surface of the rim. The rim is buried in a recess which is bulged in the inner surface direction. Furthermore, in the resonance sound preventing device for a brake shoe according to claim 3 of the present invention, the mass body sandwiched between the both sides of the web is inserted into a hole penetrating through the web, so that It is characterized by being crimped with its head.

[0010]

In the above-described apparatus for preventing resonance of a brake shoe according to the first aspect of the present invention, a mass body is buried inside the rim at a portion where the resonance amplitude of the rim is increased, and the resonance amplitude of the web is reduced. Since the mass body is sandwiched between both sides of the web in the enlarged portion, the resonance sound of the web is suppressed together with the resonance sound of the rim, and the generation of the resonance sound of the entire brake shoe is prevented.

In the apparatus for preventing resonance of a brake shoe according to claim 2 of the present invention, the mass body embedded in the rim is sandwiched between the lining and the rim and embedded in the recess of the rim. The mass body does not fall off, and the resonance prevention effect is well maintained for a long time. Furthermore, in the resonance sound preventing device for a brake shoe according to claim 3 of the present invention, since the mass body sandwiched between the webs is caulked with the heads on both sides of the web, the mass body falls off. Therefore, the effect of preventing resonance is maintained well over a long period of time.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a brake shoe according to an embodiment of the present invention; FIG. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1, FIG. 3 is a waveform diagram comparing resonance characteristics between the brake shoe according to the present invention and a conventional brake shoe, and FIG. FIG. 5 is a perspective view showing a resonance state, and in FIGS. 1 to 4, the same reference numerals as those in FIG. 5 indicate substantially the same parts.

In FIGS. 1 and 2, reference numeral 2 denotes a brake shoe. The brake shoe 2 has an arc-shaped rim 3 having a lining 5 stretched on an outer surface thereof and a circumferentially extending rim 3 on an inner surface thereof. And a web 4 that is orthogonally fixed. The rim 3 has a lining 5 at the time of braking.
In a portion where the resonance amplitude of the rim 3 including the maximum is largest, a mass body 9 such as lead is embedded as a mass so as to be enclosed inside the rim 3.

Similarly, a mass 10 such as lead is sandwiched as a mass so as to penetrate the surface of the web 4 and sandwich the web 4 from both sides at a portion where the resonance amplitude of the web 4 during braking is the largest. I have. By the way, the portion where the resonance amplitude of the rim 3 and the web 4 becomes the largest will be described in more detail with reference to FIG.

The waveform shown by the dotted line a in FIG. 4 is the resonance waveform of the rim 3 and the waveform shown by the dotted line b is the resonance waveform of the web 4, and is the end of light to medium braking at a low speed of 40 to 50 km / h. 5 shows a state of resonance of the brake shoe 2 which occurs near the resonance frequency of 3.5 to 3.6 KHz. That is, the rim 3 and the web 4 at a portion corresponding to a portion commonly called a belly where the amplitude of the resonance waveform is the largest.
Are provided with mass bodies (mass) 9 and 10 on the surface portion thereof.

Further, FIG. 4 shows only the resonance waveform on one side of the rim 3, but in fact, the antinode of the waveform is substantially similar on the other side of the rim 3 to the opposite side to the one side. Although such resonance waveforms can be seen, since the positions are substantially the same, FIG. 1 shows a state where the mass body 9 is buried at substantially symmetric positions on both sides of the rim 3. Therefore, in FIG. 1, the mass bodies 9 provided on the rim 3 are provided symmetrically, but may be provided asymmetrically in some cases.

The mass body 10 provided on the web 4
However, although FIG. 2 shows the web provided at the middle height position of the web 4, the web 4 is not necessarily limited to the middle position, but may be provided vertically. . Furthermore, the masses 9 and 10 may be set according to differences in models, resonance characteristics, and the like, such as those having different sizes and weights, or being provided as a plurality of divided bodies.

In FIG. 4, the portion where the resonance amplitude is the largest is the antinode, whereas the zero point where the waveform moves to the opposite side is the node. With such a configuration, the mass body 9 embedded in the rim 3 suppresses the resonance generated in the rim 3 during braking, and the mass body 10 sandwiched between the webs 4 also suppresses the resonance generated in the web 4. 2 can suppress the entire resonance.

FIG. 3 compares resonance waveforms of a conventional brake shoe without a mass (mass) and a brake shoe with a mass (mass) provided on a rim and a web according to the present invention. While the resonance waveform c of the conventional product shown by a solid line around 0.6 KHz is extremely increased,
The resonance waveform d of the product of the present invention indicated by the broken line is remarkably damped.

Further, the mass body 9 embedded in the rim 3 is
As shown in FIG. 2, lead or the like is cast into a recess 11 in which the surface of the rim 3 bulges inward, and the rim 3 is attached so as to be sandwiched between the lining 5 and the rim 3 by adhesion of the lining 5. Therefore, there is no danger that the mass body 9 may be separated like a thing simply attached by spot welding or the like,
The fixed state is maintained for a long period of time, so that the vibration damping effect can be exhibited well, and the detachment of the mass body 9 does not damage other mechanisms at all.

The mass body 10 sandwiched between the webs 4
As shown in FIG. 2, lead or the like is inserted into a through hole 12 provided in the surface portion of the web 4 and both ends thereof are caulked to form a head 10.
a is formed so as to sandwich the web 4 from both sides. In this case, if necessary, a metal having hardness may be enclosed inside the mass body 10 such as lead, or a metal having hardness other than lead may be used as the mass body.

Therefore, the mass body 1 having heads on both sides
Numeral 0 is firmly and firmly fixed to the web 4 with the web 4 interposed therebetween and does not come off unintentionally.
The detachment of 0 does not cause any damage to other mechanisms.

[0023]

As described above in detail, according to the first aspect of the present invention, there is provided an apparatus for preventing resonance of a brake shoe comprising an arc-shaped rim and a web fixed perpendicularly to the inner surface of the rim. In the brake shoe, since the mass body is buried inside the rim at the portion where the resonance amplitude of the rim increases, and the mass body is sandwiched between both surfaces of the web where the resonance amplitude of the web increases. In addition, there is an advantage that the resonance of the rim portion of the brake shoe is suppressed and the resonance of the web portion is suppressed, so that the vibration damping effect of the entire brake shoe can be sufficiently exhibited.

According to the apparatus for preventing resonance of a brake shoe according to the second aspect of the present invention, the mass body embedded inside the rim is sandwiched between the rim and the lining adhered to the surface of the rim. Since the rim is buried in the recess bulged in the inner surface direction, the mass body is firmly fixed to the rim, and there is no danger of detachment over a long period of time. In addition, there is an advantage that there is no adverse effect such as damage to other mechanisms due to detachment of the mass body.

Further, according to the apparatus for preventing resonance of a brake shoe of the present invention according to claim 3, the mass body sandwiched between both sides of the web is inserted into a hole penetrating through the web, and Since the web is crimped with its head on both sides, the mass is firmly fixed to the web and can maintain a good vibration-damping effect without any risk of detachment over a long period of time. There is an advantage that there is no adverse effect such as damage to other mechanisms due to separation.

[Brief description of the drawings]

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

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a waveform diagram comparing resonance characteristics of a brake shoe according to the present invention and a conventional brake shoe.

FIG. 4 is a perspective view showing a resonance state of each part of the brake shoe without a mass body.

FIG. 5 is a partial front view showing an example of an internal mechanism of a general drum brake.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 brake drum 2 brake shoe 3 rim 4 web 5 lining 6 anchor pin 7 wheel cylinder 8 return spring 9 rim mass 10 web mass 10a head 11 recess 12 through hole

Claims (3)

(57) [Claims] 1. A brake shoe comprising an arc-shaped rim and a web fixed to the inner surface of the rim at right angles, wherein a mass body is buried inside the rim at a portion where the resonance amplitude of the rim increases. In addition, a mass sound body is sandwiched between both surfaces of the web at a portion where the resonance amplitude of the web is increased, wherein a resonance noise preventing device for a brake shoe is provided. 2. A mass body embedded in the rim is sandwiched between the rim and a lining adhered to a surface of the rim, and is embedded in a recess that bulges the rim inward. The resonance sound preventing device for a brake shoe according to claim 1, wherein 3. A mass body sandwiched between both sides of the web,
2. The device according to claim 1, wherein said device is inserted into a hole penetrating through said web and is caulked with its head on both sides of said web.