JP3004157B2 - Vehicle brake brake - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake shoe for a vehicle brake which can improve the braking performance of a friction brake used in a vehicle.

[0002]

2. Description of the Related Art An object moving on the ground is equipped with a braking device that utilizes friction in some way to stop or slow down its movement. For railway vehicles. Equipped with a treadle brake or disc brake. The tread brake type brake is a brake of a type in which a brake is pressed against a tread surface of a vehicle to obtain a braking force. The brake shoe materials are roughly classified into three types: cast iron, resin, and sintered metal.

[0003] The tread brake system is adopted in conventional line vehicles of JR companies. In any case, on a conventional line, it is necessary to satisfy a condition that the vehicle stops within a mileage of 600 m after the brake is started to be applied. With the speeding up of trains on conventional lines being promoted, the development of brake shoes with excellent braking performance is required. By the way, compared to cast iron brake shoes, resin brake wheels and sintered metal brake wheels have high braking performance, but the problem is that it may not be possible to ensure stable braking performance under wet conditions, especially under snowfall conditions. is there. In addition, there is room for improvement in aggression to wheels (wear, heat load) and the like. For this reason, it has been desired to develop a brake shoe made of cast iron and having high braking performance, or a brake shoe having stable braking performance under wet conditions even in a resin or sintered metal system.

As a remedy, a special cast iron brake shoe has been developed in which P or Cr is added to cast iron to improve wear resistance and braking performance in a high speed range. Friction performance is improved by dispersing and precipitating steadite (Fe-P ternary eutectic), cementite, and carbide having higher hardness than the matrix structure by adding an alloy element. However, even in this method, there is an upper limit to the effect of improving the performance by the alloy additive, and the limit is to stop at a vehicle speed of 135 km / h to 600 m at the start of braking. In order to further improve the performance, a method of dispersing ceramic particles in cast iron is also being studied, but the target material has not been manufactured due to a large difference in specific gravity.

Further, the present inventors have previously described Japanese Patent Application No.
In 6396, a new high-performance brake was proposed. In this method, ceramic particles are externally supplied to a friction surface between a brake shoe and a wheel to increase the friction coefficient of the surface. However, in this method, a supply device for ceramic particles must be separately provided, and the entire brake device becomes complicated. In addition, resin-based snow-resistant bicycles have also been developed, but their performance has not been sufficiently obtained.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a brake shoe for a vehicle brake in which the conventional friction characteristics are greatly improved.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a brake shoe for a vehicle according to the present invention has a cast iron brake body including a friction surface pressed against a wheel of a railway vehicle, and is embedded in the brake body. A ceramic block that is partially exposed to the friction surface; and a ceramic particle that falls off the block due to contact between the ceramic block and the wheel is supplied to the friction surface;
It contributes to an increase in the coefficient of friction between the brake shoe and the wheel. That is, conventionally, hard materials were uniformly dispersed in the material to improve braking performance, whereas
In the present invention, ceramic particles as a hard substance are formed into a block shape in advance and embedded in cast iron. The ceramic block functions to supply ceramic particles to a friction interface during a brake operation, and contributes to an improvement in a friction coefficient.

[0008]

[Operation] In the development process of special cast iron brake shoes and the practical use of resin brake wheels and sintered metal brake wheels, it was clarified that the presence of hard ceramics on the brake friction surface contributed to the improvement of the friction coefficient. As a method of supplying such ceramic particles to the friction interface required during braking, the ceramic particles are formed in a block shape in advance and embedded in the brake shoe main body, and the ceramic particles are separated and supplied to the friction interface during braking. I am trying to.

[0009]

Embodiments of the present invention will be described below. FIG. 1 is a view showing a vehicle brake brake according to an embodiment of the present invention. (A) is a side view, (B) is a front view. FIG. 2 is a photograph showing a state after the brake test of the real brake shoe corresponding to FIG. The brake shoe 1 of this embodiment includes a back metal 3, a brake shoe main body 5, and a ceramic block 7. Back metal 3
The mild steel plate (SS400 or the like) covers the anti-friction surface 9 side of the brake shoe main body 5 and supports the brake shoe main body 5. That is, since the brake shoe main body 5 is made of high-hardness cast iron, cracks are likely to be generated starting from frictional heat cracks or the like on the friction surface 9, and some kind of holding body is required.

The brake shoe main body 5 is cast so as to cast the back metal 3 and the ceramic block 7. The curved concave surface of the brake shoe main body 5 is a friction surface 9 which is pressed against a tread surface (not shown) of the wheel to obtain a braking force.
A ceramic block 7 is provided at the upper and lower ends of the brake body 5.
Are embedded three by three. Ceramic block 7
Is a cylindrical block, one surface of which is exposed on the friction surface 9. When the ceramic block 7 is pressed against the wheel, part of the ceramic particles constituting the ceramic block 7 fall off and are supplied to the friction surface 9 to increase the friction coefficient between the surface and the wheel. Therefore, the braking performance is improved. The reason why the ceramic blocks 7 are arranged at both ends of the brake shoe main body 5 is to ensure that the dropped ceramic particles are supplied to the friction surface 9 even when the wheel is rotated in both forward and reverse directions.

The brake shoe main body 5 of this embodiment is made of special cast iron (NHF). By the way, N
An example of the components of HF is as follows. C: 3.02 S: 1.93 Mn: 1.41 P: 1.85 S: 0.04 Ni: 0.53 Cu: 0.52 Mo: 1.01 Cu: 0.8
6

The ceramic block 7 of this embodiment is
It is a low-density sintered body of SiC (diameter 30 × h45 mm).
The molding conditions for this ceramic block are as follows. Average particle size: 100μ Molding method: Slurry pouring Firing conditions: 900 ° C, hold for 30 minutes, normal pressure Porosity: 30-40%

One of the points of the present invention is that when the ceramic block comes into contact with the wheel, the ceramic particles fall off moderately. In addition to the low-density sintered body as in this embodiment, a suitable ceramic block may be formed by, for example, resin or cement.

A full-scale brake test was performed using the brake shoe manufactured as described above. In this test machine, a wheel with the same moment of inertia as an actual vehicle is rotating at a predetermined speed, and the brake is pressed against the wheel, and the instantaneous friction coefficient, the number of revolutions before stopping (brake distance) and time are calculated. It was measured. The brake shoe tested is a currently used alloy cast iron brake shoe (NHF) for high-speed vehicles and a blocker (NHF / SiC) in which ceramics (SiC) particles are formed into blocks and cast. .

FIG. 3 shows the speed from the initial brake speed of 140 km / h to the stop of the wheel with the brake applied (horizontal axis).
4 is a graph showing the relationship between the coefficient of friction and the instantaneous friction coefficient (vertical axis).
It can be seen that the friction coefficient of the brake shoe in which the SiC block is embedded is high in almost the entire region from the high-speed region where braking is started to the low-speed region immediately before stopping. In this test, the braking distance from the start of braking to the stop of the wheel was also measured. The brake distance of the product of the present invention was also shortened by 30% or more compared to the conventional NHF product. In addition,
The wear amount of the brake shoe was increased by about 20% in the product of the present invention, but this is not a problem in view of the improvement of the braking function.

[0016]

As described above, the brake shoe for a vehicle according to the present invention is embedded in the brake shoe main body without any modification to the brake device or mounting any additional device. The function of the ceramic particles supplied from the ceramic block can significantly improve the braking performance of the cast iron brake shoe.

[Brief description of the drawings]

FIG. 1 is a view showing a vehicle brake brake according to an embodiment of the present invention. (A) is a side view, (B) is a front view.

FIG. 2 is a photograph showing a state after a brake test of a real brake shoe corresponding to FIG. 1 (B).

FIG. 3 is a graph showing a relationship between a speed (horizontal axis) from an initial brake speed of 140 km / h until a wheel is stopped by applying a brake and an instantaneous friction coefficient (vertical axis).

[Explanation of symbols]

DESCRIPTION OF REFERENCE NUMERALS 1 brake shoe 3 back metal 5 brake shoe body 7 ceramic block 9 friction surface

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Shinichi Katayama 2-8-8 Hikaricho, Kokubunji-shi, Tokyo Inside the Railway Technical Research Institute (72) Inventor Takumi Ban, 2-chome Hikaricho, Kokubunji-shi, Tokyo No. 38 Inside the Railway Technical Research Institute (72) Inventor Junji Watari 43-7, Midorigaoka, Ebetsu-shi, Hokkaido, Japan Person Junichi Nakayama 8-3-3 Kita 5-Jo Higashi, Higashi-ku, Sapporo, Hokkaido (56) References JP-A-57-80907 (JP, A) JP-A-49-119326 (JP, A) JP-A-5-213197 (JP, A) JP-B 36-7202 (JP, B1) JP-B 17-7346 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16D 65/06 F16D 69 / 00

Claims (3)

(57) [Claims] 1. A cast iron brake shoe main body including a friction surface pressed against a wheel of a railway vehicle, and a ceramic block embedded in the brake shoe body and partially exposed to the friction surface. A brake particle for a vehicle brake, wherein the ceramic particles falling off from the block due to the contact between the ceramic block and the wheel are supplied to the friction surface and contribute to an increase in the coefficient of friction between the brake wheel and the wheel. . 2. A brake shoe body made of high-hardness cast iron including a friction surface pressed against a wheel of a railway vehicle, and a bush covering the brake shoe body opposite to the friction surface and supporting the brake shoe body.
And Kkumetaru, is embedded in the braking Waco body, part of which is exposed to the friction surface, includes a ceramic block, a; ceramic particles above the friction surface from falling off the same block by contact with the ceramic block and the wheel Characterized in that it is supplied to the vehicle and contributes to an increase in the coefficient of friction between the brake shoe and the wheel. 3. A brake body made of cast iron including a friction surface pressed against a wheel of a railway vehicle, and a ceramic block embedded in the brake body by casting and partially exposed to the friction surface. ,
Comprising a; ceramic particles from falling off the same block by contact with the ceramic blocks and the wheels is supplied to the friction surface, a vehicle brake system Waco contribute to friction increase between the brake shoe and the wheel The above ceramic blocks are arranged at both ends of the brake shoe body
Is lost, even when the wheel rotates in both forward and reverse directions.
The mixed particles are supplied to the brake shoe friction surface.
Brake shoe for vehicle braking.