JP2006177404A - Brake disc fastening structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake disc fastening structure for stably fastening brake discs without biting fastening components into the brake discs. <P>SOLUTION: A bolt 3 has a stepped portion 3b at the front end for fastening the pair of aluminum base composite material brake discs 2 to a railway wheel 1 and a small-diameter portion 3c at the tip thereof to which a nut is threaded. The stepped portion 3b restricts the movement of the nut 4 to the fastening side. Thus, the brake discs 2 are fastened via flat washers 8a, 8b with certain fastening force by the elastic resilience of a disc spring washer 10 and the brake discs 2 are stably fastened without biting the flat washeres 8a, 8b into the brake discs 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a structure for fastening a brake disc to a railway wheel, and particularly to a fastening structure suitable for a brake disc made of an aluminum-based composite material.

  Rail wheels are often used with a brake disc fastening structure that uses a space on the side of the wheel to fasten a pair of brake discs on both sides with bolts and nuts. The brake disc is lightweight and has excellent sliding characteristics. It is thought that the adoption ratio of those made of aluminum based composite materials will increase. The aluminum-based composite material is obtained by dispersing particles and fibers such as SiC ceramic in an aluminum alloy.

  This aluminum-based composite brake disc is lightweight and has excellent sliding characteristics, but it is softer than steel fastening parts such as bolts, nuts, and washers used for fastening. There is a problem that a step is formed by biting into the edge of the bolt hole of the brake disk, and stress concentration occurs in the bolt hole edge where the step is formed due to thermal stress caused by frictional heat generation, and cracks are likely to occur.

  The brake disc fastening structure that prevents the fastening parts from biting into the brake disc includes a collar that passes through the bolt holes of the aligned rail wheel and the pair of brake discs, and both ends of the collar are connected to the rail wheel. Projecting from the brake discs superimposed on both sides, inserting bolts into the collar, elastic restoring force between the brake discs on the head side of the bolt and the nut side screwed to the tip of the bolt, respectively A structure has been proposed in which movement of the nut to the tightening side is regulated by a collar by interposing a washer having a clamp, and a brake disk is fastened with a constant tightening force by a washer having an elastic restoring force (for example, a patent) Reference 1).

JP 2000-240697 A

  The brake disc fastening structure described in Patent Document 1 can prevent the fastening parts from biting into the brake disc described above, but the thin cylindrical collar is easily buckled by the tightening force of the nut. In consideration of expansion of the brake disk due to thermal expansion, when the bolt hole is a long hole slightly longer in the disk radial direction, the collar is more likely to buckle. Since this collar buckling is difficult to confirm from the outside, there is a possibility that a step is generated in the brake disc due to excessive tightening.

  In order to prevent the collar from buckling, it is only necessary to increase the thickness of the collar. However, if the thickness of the collar is increased, the bolt hole of the brake disk becomes large and the strength of the brake disk is reduced.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a brake disk fastening structure capable of stably fastening a brake disk without causing fastening parts to bite into the brake disk.

  In order to solve the above-described problems, the present invention is configured to fasten a pair of aluminum-based composite brake discs on both sides of a railway wheel with bolts and nuts that are screwed to the front ends of the bolts. In the brake disc fastening structure with a washer having an elastic restoring force between them, a step having a small diameter portion is provided at a tip end side of a bolt to which the nut is screwed, and this step leads to a tightening side of the nut. Adopted a configuration to regulate the movement of.

  That is, by providing a step with a small diameter portion at the tip of the bolt to which the nut is screwed, and restricting the movement of the nut to the tightening side with this step, the brake disc is fixed with a washer having an elastic restoring force. The brake disc can be stably tightened without tightening with force and causing the fastening parts to bite into the brake disc. As the washer having elastic restoring force, a spring washer, a disc spring washer, or the like can be used.

  By placing a plain washer between the washer having the elastic restoring force and the brake disc, the hitting of the washer having the elastic restoring force such as a spring washer and a disc spring washer to the brake disc can be evenly dispersed. it can.

  The fastening structure of the brake disk of the present invention is provided with a step having a small diameter portion on the tip side of the bolt to which the nut is screwed, and this step restricts the movement of the nut to the tightening side. The brake disk can be stably tightened without tightening the brake disk with a certain tightening force by the washer having the above-mentioned and causing the fastening parts to bite into the brake disk.

  By placing a plain washer between the washer having the elastic restoring force and the brake disc, the hitting of the washer having the elastic restoring force such as a spring washer and a disc spring washer to the brake disc can be evenly dispersed. it can.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, this brake disk fastening structure is a structure in which a pair of aluminum-based composite brake discs 2 are fastened with bolts 3 and nuts 4 on both sides of a railway wheel 1. A flat sliding surface 5 is provided on the front side of each disk 2 and fins 6 for heat radiation are provided on the back side, so that the brake pad 7 is pressed against each sliding surface 5 from both sides.

  The bolt 3 is inserted into the bolt holes 1a, 2a of the railway wheel 1 and the brake discs 2 with a plain washer 8a interposed between the head 3a and one of the discs 2, and the front end side thereof. A flat washer 9, a plurality of disc spring washers 10 as a washer having elastic restoring force, and a flat washer 8b are interposed between the nut 4 and the other disk 2 screwed together. The bolt hole 2a of each disk 2 is a long hole slightly longer in the radial direction in consideration of the diameter expansion due to thermal expansion of the disk 2.

  As shown in an enlarged view in FIG. 2, the nut 4 is screwed to the small diameter portion 3 c at the tip of the step 3 b provided on the tip side of the bolt 3, and is moved to the tightening side by the step 3 b through the flat washer 9. Is regulated. Accordingly, each disk 2 is stably clamped with a constant clamping force via the flat washers 8a and 8b by the elastic restoring force of the disc spring washer 10. The thickness of each flat washer 8a, 8b can be adjusted according to the measured value by measuring the distance from the surface of the brake disk 2 to the step 3b of the bolt 3 during tightening.

  Further, in the embodiment described above, the disc spring washer having the elastic restoring force is interposed only on the nut side, but the disc spring washer may be interposed on the head side of the bolt. Further, as the washer having the elastic restoring force, another type such as a spring washer may be used.

A longitudinal sectional view showing an embodiment of a brake disk fastening structure Sectional drawing which expands and shows the principal part of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rail wheel 1a Bolt hole 2 Brake disk 2a Bolt hole 3 Bolt 3a Head 3b Step 3c Small diameter part 4 Nut 5 Sliding surface 6 Fin 7 Brake pads 8a, 8b, 9 Flat washer 10 Belleville spring washer

Claims (2)

  A pair of aluminum-based composite brake discs are fastened to both sides of a railway wheel with bolts and nuts that are screwed onto the front ends of the bolts, and a washer having elastic restoring force is interposed between the nuts and the brake disc. The brake disc fastening structure according to the present invention is characterized in that a step having a small-diameter portion is provided on a tip side of a bolt to which the nut is screwed, and the movement of the nut to the tightening side is regulated by this step. Brake disc fastening structure.   The brake disk fastening structure according to claim 1, wherein a flat washer is interposed between the washer having the elastic restoring force and the brake disk.

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