JP2005256858A - Brake disc for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake disc for a vehicle, in which thermal stress generated in use is reduced in itself, and in which generation of deformation due to thermal stress such as thermal cracking, disc deformation, damages in fastening bolts, etc., can be prevented. <P>SOLUTION: In this brake disc for a vehicle, special alloy having a low thermal expansion coefficient is used to be integrated. Workability, friction abrasion resistance, and structural reliability, that are similar to those of current material are secured, while generation of cracking can be drastically restricted, with damages in fastening bolts prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a vehicle brake disc, and more particularly to a vehicle brake disc mounted on a side surface of a railway wheel.

  Railway vehicle mechanical brake devices are divided into a tread brake system that directly applies a brake to the tread surface of a wheel and a disc brake system that applies a brake pad (also called brake lining) to a brake disc that is exclusively equipped for braking. Is done.

  The latter is mainly used in high-speed vehicles such as Shinkansen trains because the heat load during braking is large.

There are two types of disc brake systems: one that installs a brake disc independent of the wheel on the axle, and one that attaches a brake disc to the side of the wheel and fastens it to the wheel. The latter is used in an electric vehicle equipped with a drive device on the axle and having a small space.
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  The current brake disc is not divided in the circumferential direction and is an integral structure, so positioning at the time of mounting is easy, the balance as a rotating body is excellent, and the sliding surface is a continuous flat surface, so friction with the mating material Good wear characteristics. Also, the structure and fastening method of the brake disk are simple, and there is no contact sliding portion inside the brake disk, so that the structural reliability is excellent.

  On the other hand, there are the following problems.

  The brake disc has a corresponding thickness, and the inclined deformation to the back is physically constrained by the wheels. For this reason, a significant thermal stress is generated by the heat input from the friction surface during braking, and this thermal stress causes compression plastic deformation of the disk sliding surface. To do. Residual stress accumulates sequentially due to repeated braking, and if the tensile strength of the material is exceeded, the brake disc will thermally crack.

  In addition, the warp deformation of the disk is caused by the accumulation of residual stress, and the sliding friction state with the brake lining is deteriorated. In addition, the load on the fastening bolt is increased, which causes bolt damage.

  Thus, the current brake disc may crack after a corresponding period of use with the accumulation of residual stress, and an increase in load on the fastening bolt is inevitable.

  By the way, the current brake disc is mainly intended to prevent thermal cracks and disc deformation at the initial stage of use against repeated thermal stress by setting the material strength and toughness high.

  On the other hand, in the present invention, the concept of the material used is changed, the thermal stress itself generated during use is reduced, and the occurrence of deformation due to thermal stress such as thermal cracking, disk deformation, fastening bolt damage, etc. An object of the present invention is to provide a brake disc for a vehicle that can be restrained in advance.

In order to achieve the above object, the present invention provides
[1] The vehicle brake disc is characterized in that a special alloy having a low thermal expansion coefficient is formed as an integral member.

  [2] The vehicle brake disc according to [1], wherein the integrated member is mounted on a side surface of a railway wheel.

[3] In the vehicle brake disc according to the above [1] or [2], the special alloy has an average linear expansion coefficient of 9 × 10 ⁻⁶ / ° C. or less in a temperature range of room temperature to 400 ° C. At an arbitrary temperature of 400 ° C. to 800 ° C., the temperature is set to T ° C. and is (0.01T + 5) / ° C. or less.

  [4] The vehicle brake disk according to [3], wherein the special alloy includes 25-40% by weight of Ni based on Fe, or 25-40% by weight of Ni and 3-20% by weight of Ni. It is characterized by containing Co.

  [5] The vehicle brake disk according to [4], further comprising Cr 1-5 wt%, Mn 0.1-1 wt%, Si 0.05-1 wt%, Al 0.1-2 wt%, Ti0 .. 2-2% by weight, Nb 0.1-6% by weight, Cu 0.1-1% by weight, C 0.01-0.2% by weight, or a part or all of C0.01-0.2% by weight.

  According to the present invention, a special alloy having a low coefficient of thermal expansion is applied as an integral member in a brake disc that is mainly used by being mounted on a side surface of a railway wheel. As a result, while maintaining the same workability, friction and wear characteristics, and structural reliability as the brake steel integrated structure brake disc currently used, the generated thermal stress is greatly reduced, cracking is suppressed, and fastening bolt damage is prevented. Is possible.

  Introducing a fundamentally different philosophy of brake disc material and design. Whereas the current material has a design and material that gives material strength that can resist the generated thermal stress, the present invention has a material and design that reduces the generated thermal stress itself without losing any of the advantages of the current material. To do. As a result of thermal stress analysis, generated thermal stress, residual stress, and warpage deformation of the disk are remarkably reduced by using a low thermal expansion alloy whose coefficient of thermal expansion as material constant is extremely low compared with ordinary structural metal materials. Was confirmed. In the present invention, by applying a low thermal expansion alloy to the material of the brake disc material, the generated thermal stress itself is reduced, and the generation of cracks can be suppressed. Moreover, it is not divided | segmented into the circumferential direction, and can demonstrate the advantage of an integral structure. There are many materials for low thermal expansion alloys, but the structural low thermal expansion alloys of the present invention are excellent in strength, hardness, toughness, and wear resistance, and are particularly excellent in heat resistance. It is suitable as a disk material. As described above, according to the present invention, it is possible to suppress drastic cracking and prevent fastening bolt damage while ensuring workability, friction and wear characteristics, and structural reliability equivalent to those of current materials.

  Hereinafter, embodiments of the present invention will be described in detail.

  1 is a perspective view of a brake disc mounted on a side surface of a railway wheel according to the present invention, FIG. 2 is a cross-sectional view of a wheel on which a brake disc is mounted and fastened, and FIG. 3 is a schematic diagram of a brake caliper acting on the brake disc. FIG.

  In these drawings, 1 is a wheel, 2 is a wheel plate portion of the wheel 1, 3 and 4 are brake discs attached to the wheel plate portion 2, 5 is a through-hole portion for fastening a bolt, 6 is a fastening bolt, Reference numeral 7 denotes a brake caliper, and 8 denotes a brake pad (also referred to as a brake lining) provided on the brake caliper 7.

  The railroad vehicle mechanical brake device according to the present invention applies a friction braking force by pressing the brake pads 8 exclusively against the brake disks 3 and 4 that are equipped for braking.

  The brake disks 3 and 4 are provided on the both sides of the wheel 1 coaxially with the wheel 1, and the anti-wheel side is a friction surface (surface) with the brake pad 8. The wheel side of the brake discs 3 and 4 has a shape suitable for installation on the wheel plate portion 2 and may be provided with a shape such as a cooling fin. There are a case where the rear surfaces of the brake disks 3 and 4 are in contact with the wheel plate portion 2 and a case where a gap is provided between the brake disc 3 and the wheel plate portion 2.

  As shown in FIG. 2, in order to apply a frictional braking force to the brake discs 3 and 4, the brake discs 3 and 4 are mounted so as to sandwich the entire wheel 1 from both sides. The brake discs 3 and 4 installed on both sides of the wheel 1 are fastened to the wheel 1 by fastening bolts 6 through a plurality of through holes 5 provided in the wheel 1 and the brake discs 3 and 4. Then, the brake pad 8 attached to the brake caliper 7 shown in FIG. 3 is pressed against the friction surface of the brake discs 3 and 4 shown in FIG. The brake pad 8 rubs only the friction surfaces of the brake disks 3 and 4.

  Next, the nominal alloy composition (unit: wt%) of the low thermal expansion alloy applicable to the present invention is shown in Table 1.

本発明に適用可能な低熱膨張合金としては、ＨＲＡ９２９、Ｉｎｃｏｌｏｙ（登録商標）９０３、Ｉｎｃｏｌｏｙ（登録商標）９０７、Ｉｎｃｏｌｏｙ（登録商標）９０９、Ｉｎｃｏｎｅｌ（登録商標）７８３等があり、それぞれの合金組成が示されている。

Examples of the low thermal expansion alloy applicable to the present invention include HRA929, Incoloy (registered trademark) 903, Incoloy (registered trademark) 907, Incoloy (registered trademark) 909, Inconel (registered trademark) 783, etc. It is shown.

  In addition to these low thermal expansion alloys, special alloys having the following compositions can be applied in the present invention.

  (1) Special alloy in which Fe is used as a base material and 25-40 wt% Ni or 25-40 wt% Ni and 3-20 wt% Co are blended.

  (2) Further, in addition to the alloy composition of (1) above, Cr 1-5 wt%, Mn 0.1-1 wt%, Si 0.05-1 wt%, Al 0.1-2 wt%, Ti 0.2- A special alloy containing a part or all of 2% by weight, Nb 0.1-6% by weight, Cu 0.1-1% by weight, and C0.01-0.2% by weight.

  Next, the temperature characteristics of the average linear expansion coefficient of the brake disc material will be described.

FIG. 4 is a temperature characteristic diagram of the average linear expansion coefficient of the brake disc material, in which the horizontal axis indicates temperature (° C.) and the vertical axis indicates the average linear expansion coefficient (10 ⁻⁶ / ° C.).

SNCM steel is used for the current brake disc. The SNCM steel (c in the figure) has an average linear expansion coefficient of about 12 × 10 ⁻⁶ / ° C. at room temperature, whereas the low thermal expansion according to the present invention. In alloys (for example, Incoloy (registered trademark) 909 (a in the figure), HRA929 (b in the figure), etc.), the temperature is 8 × 10 ⁻⁶ / ° C. or less. Thus, the average linear expansion coefficient is greatly different in the entire temperature range from room temperature to 800 ° C., and in the case of the low thermal expansion alloy of the present invention, the average linear expansion coefficient is as small as 2/3 as compared with SNCM steel of the current technology. I understand that.

  In the present invention, this special alloy having a low thermal expansion coefficient is used as a brake disc material.

  In addition, this invention is not limited to the said Example, Based on the meaning of this invention, a various deformation | transformation is possible and these are not excluded from the scope of the present invention.

  The vehicle brake disc of the present invention is suitable as a vehicle brake disc mounted on a side surface of a railway wheel.

1 is a perspective view of a brake disc mounted on a side surface of a railway wheel according to the present invention. It is sectional drawing of the wheel by which the brake disc with which the side surface of the wheel for railways concerning this invention was mounted | worn was fastened. It is a schematic diagram of the brake caliper acting on the brake disc mounted on the side surface of the railway wheel according to the present invention. It is a temperature characteristic figure of the average coefficient of linear expansion of a brake disk material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wheel 2 Wheel plate part 3, 4 Brake disc 5 Through-hole part 6 Fastening bolt 7 Brake caliper 8 Brake pad (brake lining)

Claims (5)

  A brake disk for a vehicle, comprising a special alloy having a low thermal expansion coefficient as an integral member.   2. The vehicle brake disk according to claim 1, wherein the integrated member is mounted on a side surface of a railway wheel. 3. The vehicle brake disk according to claim 1, wherein the special alloy has an average linear expansion coefficient of 9 × 10 ⁻⁶ / ° C. or less in a temperature range of room temperature to 400 ° C., and 400 ° C. to 800 ° C. A brake disk for a vehicle, wherein the temperature is (0.01 T + 5) / ° C. or less at an arbitrary temperature.   4. The vehicle brake disk according to claim 3, wherein the special alloy contains 25-40 wt% Ni or 25-40 wt% Ni and 3-20 wt% Co based on Fe. A brake disc for vehicles.   5. The vehicle brake disk according to claim 4, further comprising: Cr 1-5 wt%, Mn 0.1-1 wt%, Si 0.05-1 wt%, Al 0.1-2 wt%, Ti 0.2-2. A brake disc for a vehicle, comprising a part or all of wt%, Nb 0.1-6 wt%, Cu 0.1-1 wt%, and C 0.01-0.2 wt%.

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