JPS6212409B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brake shoe in an internal expansion type brake.

It is well known that when a brake is applied, a sharp sound is generated due to the vibration of the brake shoe.
This is the so-called brake squeal. The idea for preventing brake squeal was published in Utility Model Publication No. 49-36755.
No., Utility Model No. 54-57274, and Utility Model No. 54-
There is number 140186.

Utility Model Publication No. 49-36755 assumes that the vibration caused by the vertical displacement of the side edge of the rim of the brake shoe, which has a T-shaped cross section, is the cause of the noise, and that the brake shoe first comes into contact with the drum. In order to increase the stiffness of that part, an L-shaped steel plate is fixed to prevent noise generation. However, since the cause of noise generation is not only caused by vertical vibration of the side edge of the rim, there is a drawback that the noise prevention effect is low.

In addition, the invention of Utility Model Application Publication No. 54-57274 has a two-rim structure in which the rim part of the brake shoe body and the backing metal are separably attached, and the contact surface between the rim part and the backing metal is formed as a blocking surface. It attempts to prevent squealing by absorbing vibrational energy. However, if the two-rim structure has the same shape, the vibration system only changes slightly, and vibration energy cannot be absorbed sufficiently. On the other hand, if an attempt is made to thicken the rim to increase its rigidity and improve the vibration energy absorption effect, the weight of the brake shoe becomes excessive, which poses the problem of making it difficult to put it to practical use.

Furthermore, the invention of Utility Model Application No. 54-140186 attempts to prevent squeal by bonding a damping material to the inner peripheral surface of the brake shoe on the drum opening side. If you try to increase the rigidity of the brake shoe with damping material, there is an inherent problem that the weight of the brake shoe itself becomes excessive, and if non-metallic materials are used for the damping material, the durability of the damping material will be insufficient. However, there is a drawback that maintenance and inspection of the brakes is not easy.

This invention solves the above-mentioned problems, and has a rim structure in which the web and rim of the brake shoe are integrally formed of cast iron, and a flat plate rim made of a flat steel plate is provided. At the same time as suppressing the vibration of the user itself,
It is an object of the present invention to provide a brake shoe that does not make noise and is capable of attenuating generated vibrations in a single time period.

This invention will be explained in detail based on illustrated embodiments.

FIG. 1 is a side view of the brake shoe according to the present invention, and FIG. 2 is a cross-sectional view of the central portion, in which 1 is a web portion of the brake shoe, and 11 is formed integrally with this web portion 1. 2 is a flat rim part riveted to the upper surface of the rim part 11, 3 is a left end rivet that rivets the rim part 11 and the flat rim part 2, 4 is a center part rivet, and 5 is a right end rivet. It is a part tack. Reference numeral 6 denotes a left end mounting stud for riveting the lining 9 to the flat plate rim portion 2, 7a and 7b represent center mounting studs, and 8 represents a right end mounting stud.

The web 1 and the rim part 11 are formed by casting cast iron, for example, ordinary cast iron FC-25, and as shown in FIG. , a main plate part 14 connected to the end edge part 13 and formed into a plate shape with some wall thickness removed in order to reduce weight, and a rim part 11 connected to the main plate part 14 and formed into an equal beam as a flat plate. The parts 14 are formed symmetrically with respect to the axis of the part 14 as an axis of symmetry. In this case, the weight ratio of the rim portion 11 and the flat rim portion 2 is set to 5.
The weight of the rim part 11 is made equal to the weight of the flat plate rim part 2, or within five times the weight of the flat plate rim part 2. In addition, in order to maintain high rigidity of the rim part 11, the width of the rim part 11 in the cross-sectional shape is formed to the minimum length necessary to allow the flat plate rim part 2 to be riveted. , so that the length corresponding to the width difference between the flat plate rim part 2 and the rim part 11 is evenly distributed. Furthermore, the riveting positions of the flat plate rim portion 2 and the rim portion 11 are based on the applicant's previous application.
54-139224 (see Japanese Utility Model Application Publication No. 56-56939), it is provided at the node and abdomen of the shoe vibration during brake operation. That is, during brake operation, the brake shoe vibrates with nodes at a distance corresponding to approximately 1/4 of the total length from both ends, and antinodes at both ends and the center. The left end rivet 3 and the right end rivet 5 are provided at the nodes of vibration of this shoe, and the center rivet 4 is provided at the abdomen. In other words, as shown in Figure 2, rivets are attached in two rows symmetrically on both sides with the web axis as the axis of symmetry in the cross-sectional shape of the brake shoe, at positions corresponding to the nodes and antinodes of the vibration of the brake shoe. form. The flat plate rim part 2 is formed of a thin steel plate into a rectangular shape, and is riveted to the rim part 11 to form a two-plate rim structure. The lining 9 is formed to be riveted to the flat plate rim portion 2. That is, the rim portion 11 and the flat plate rim portion 2 are riveted to the flat plate rim portion 2 from the side edge of the riveting position. That is, the left end mounting studs 6 are provided on the flat plate rim portion 2 corresponding to the left end studs 3, and similarly, the right end mounting studs 8 are provided on the flat plate rim portion 2 corresponding to the right end studs 5. The central portion attachment studs 7a and 7b are provided at corresponding positions close to the central portion stud 4 in order to connect the lining in the central portion with split rivets.

Next, the vibration damping effect according to the present invention will be explained based on FIGS. 3, 4, and 5. Figures 3 and 4
Both Fig. 5 and Fig. 5 show the state of vibration damping at the movable end edge of the rim of a brake shoe installed on the same brake drum. is shown in units of time, and the horizontal axis shows elapsed time in units of one-thousandth of a second. Figure 3 shows the case of a brake shoe with a single rim structure integrally formed from ordinary cast iron FC25, and the acceleration at the start point of vibration is 20,000, and the acceleration at 35,000 elapsed time is also 13,000. The attenuation curve is linear, indicating that the attenuation ability is small.

FIG. 4 shows a brake shoe having a two-plate structure made of thin steel plates. In this case, the acceleration at the vibration start point is 25,000, but the acceleration at 35,000 elapsed time is 6,000, indicating that the damping capacity is higher than that of the one with a cast iron single rim structure. Figure 5 shows a brake shoe according to this invention.
This figure shows a case in which normal cast iron FC25 is used as the cast iron, and the weight ratio of the rim portion is 2:1. In this case, the acceleration at the starting point of vibration is
It is small at 15,000, indicating that the vibration has already attenuated after 35,000 hours. Also, when elapsed
At 15,000 hours, the acceleration is already 2,000, and it can be seen that the vibration damping effect and damping effect are higher than those of the first two.

According to this invention, the rigidity of the brake shoe in the longitudinal direction can be made higher than the weight. In addition, since it is made of cast iron as a damping material, the acceleration at the starting point of vibration is small, and the energy absorption at the contact surface with the flat plate rim is good, so the damping effect is high, and the brake does not squeal and has good durability. I was able to provide a show.

[Brief explanation of the drawing]

FIG. 1 is a side view of a brake shoe according to the present invention, FIG. 2 is a cross-sectional view of the central part, FIG. 3 is a damping curve of a brake shoe with a single rim structure made of cast iron, and FIG.
The figure shows a damping curve of a brake shoe having a two-rim structure made of steel plates, and FIG. 5 shows a damping curve of a brake shoe according to the present invention. Brief explanation of the symbols: 1...web part, 11...rim part, 13...edge part, 14...main plate part, 2...flat plate rim part, 3...left end rivet, 4...center part rivet, 5...right end rivet , 6... Left end mounting stud, 7a, 7b... Center mounting stud, 8... Right end mounting stud, 9... Lining.

Claims (1)

[Claims] 1 In the brake shoe of the internal expansion type brake,
The web 1 and the rim part 11 are integrally formed of cast iron, and a thick edge part 13 is formed on the inner circumferential edge of the web 1, and the web 1 is connected to the edge part 13 and the wall thickness is removed to form a plate shape. A main plate part 14 is formed, and a rim part 11 is provided, the length of which is formed into an equal beam protruding from both sides of the main plate part 14 to the minimum length necessary to rivet the flat plate rim part 2, A flat plate rim part 2 is provided on the upper surface of the rim part 11, and the flat plate rim part 2 is formed of a rectangular steel flat plate and has a weight ratio of 5:1 to the rim part 11. The position of the node in the shoe vibration that occurs at a position spaced apart from both ends of the rim part 11 by a distance equivalent to approximately 1/4 of the total length along the arcuate periphery of the rim part 11 between the left end stud 3 and the right end stud 5. It is fixed to the rim part 11 and fixed by providing a center part stud 4 at the antinode position of the shoe vibration that occurs at the center position, and a left end part mounting stud 6 and a right end part are attached to the outer side corresponding to the left end part stud 3 of the flat plate rim part 2. A brake shoe characterized in that a right end mounting stud 8 is provided on the outer side corresponding to the section stud 5, and center section mounting studs 7a and 7b are provided at a position corresponding to the central section stud 4, and a lining 9 is connected to the lining 9 with rivets. .