JP2020122553A - brake disc - Google Patents

Abstract

To improve heat dispersing performance at the time of braking, and to reduce stress generating in a brake disc by frictional heat during braking.SOLUTION: A brake disc includes: a doughnut-shaped discoid plate part 1a whose surface side is a slide surface; a plurality of radial fin parts 2 provided radially in a protrusive manner with an interval with each other on a rear surface of the plate part 1a, and fastened to a wheel by inserting a fastening member in a bolt insertion hole 2a provided in the middle in the longer direction; and inclined fin parts 4 each of which is provided in a protrusive manner with an angle θ on both sides in the circumferential direction of these radial fin parts 2 on the rear surface of the plate part 1a. The inclined fin part 4 is integrally connected with respect to the radial fin part 2 with an angle θ of equal to or greater than 30° and equal to or less than 50°.SELECTED DRAWING: Figure 1

Description

The present invention relates to a brake disc used in a vehicle such as a railway vehicle, and more particularly to a technique for dispersing thermal energy generated by frictional heat during braking and reducing stress generated by the thermal energy.

Disc brakes used for braking railway vehicles, automobiles, airplanes, etc. generate braking force by pressing a brake pad against a brake disc that rotates with the axles and wheels, thereby braking the rotation of the axles or wheels to reduce the vehicle speed. Is known to control.

High-speed railway vehicles such as the Shinkansen are being operated at speeds exceeding 300 km per hour due to the promotion of higher speeds. It is known that the weight reduction of a vehicle is essential for speeding up a railway vehicle, and a sliding surface fastening type brake disc for directly fastening a plate portion serving as a sliding surface to a wheel is known to be suitable.

When driving at high speed, noise called aerodynamic noise is induced, so it is necessary to reduce aerodynamic noise in consideration of the environment. Patent Document 1 discloses a brake disc in which ribs are added along the circumferential direction between adjacent radial fin portions, and the flow of air is suppressed by the ribs.

The brake disc of Patent Document 2 has a concave portion on its fastening surface that fits with a convex portion provided on a fastened member (wheel or the like) for the purpose of reducing deformation such as warpage caused by frictional heat during braking. doing.

Further, in the brake disc of Patent Document 3, the ratio of the total volume of the fastening portion and the non-fastening portion is defined, strain is prevented from concentrating on a part, and warpage and undulation are suppressed.

In Patent Document 4, by optimizing the positional relationship between the contact position with the wheel on the inner and outer circumferences of the brake disc and the fastening hole, the bending load on the bolt is reduced and the durability of the bolt is ensured. ..

Further, in the brake disc of Patent Document 5, a donut-shaped disc portion having a front surface side as a sliding surface, a plurality of radial fin portions radially provided on the back surface of the disc portion, and the disc portion. Further, a bolt hole penetrating the radial fin portion is provided, and the disc portion is attached to the wheel in a state where the radial fin portion is pressed against the plate portion of the wheel by fastening with a bolt inserted in the bolt hole. In this radial fin portion, by forming grooves along the circumferential direction in a radially inner region and a radially outer region sandwiching the bolt hole, cooling performance during braking is improved, The durability of the brake disc including the fastening bolts is improved.

Japanese Patent No. 5158209 JP, 2001-311441, A JP, 2005-321091, A JP, 2006-9862, A Patent No. 5924413

For example, according to the brake disc as disclosed in Patent Document 1, the aerodynamic noise can be reduced to a desired level, but there is a problem that the cooling performance of the brake disc is reduced during braking due to the suppression of the gas flow by the rib. Manifest. Further, when the emergency brake is applied from the high speed running state, the deformation due to the thermal expansion of the brake disc and the stress load on the fastening bolt due to the deformation increase, and it is difficult to secure the durability of the brake disc and the bolt. Become.

As described above, in the brake discs of Patent Documents 1 to 5 described above, a method of coping with the generated thermal stress is specified, but the generated stress is not sufficiently reduced, and the generated thermal energy is still insufficient. There is room to fully disperse.

The present invention focuses on the above problems and aims to improve the heat dispersion performance during braking and to reduce the stress generated in the brake disc due to the frictional heat during braking.

In order to achieve the above object, in the present invention, the stress generated in the brake disc due to frictional heat is suppressed.

Specifically, in the first invention,
A donut-shaped disc-shaped plate having the front surface as a sliding surface,
A plurality of radial fin portions which are radially provided at intervals on the back surface of the plate portion, and which are fastened to the wheel by inserting a fastening member into a bolt insertion hole provided in the middle in the longitudinal direction,
On the back surface of the plate portion, provided with inclined fin portions respectively provided on both sides in the circumferential direction of the radial fin portion at an angle,
The inclined fin portion is integrally connected to the radial fin portion at an angle of 30° or more and 50° or less.

That is, if the radial fins are connected to each other at an angle smaller than 30°, it is difficult to connect the inclined fins to the radial fins. However, according to the above configuration, since the inclined fin portion is connected to the heat radiation fin portion at an appropriate angle, an appropriate surface area can be secured and further heat dispersion can be expected.

As described above, according to the present invention, the inclined fin portion projecting from the plate portion of the brake disc is connected to the radial fin portion through which the fastening member is inserted at an angle of 30° or more and 50° or less. It is possible to improve the heat dispersion performance during braking and reduce the stress generated in the brake disc due to the frictional heat during braking.

FIG. 4B is an enlarged front view of a portion I of FIG. 4A. It is a front view showing a wheel with which a brake disc concerning an embodiment of the present invention was fastened. It is the III-III sectional view taken on the line of FIG. It is a rear view which shows the back surface of the brake disc which concerns on embodiment of this invention. It is a perspective view showing the back of a brake disc concerning an embodiment of the present invention. It is a figure which shows the temperature analysis result which concerns on an Example and a comparative example when changing a diagonal angle. It is a figure which shows the stress analysis result which concerns on an Example and a comparative example when changing a diagonal angle. It is a figure which shows the temperature analysis result which concerns on an Example and a comparative example when changing the fin thickness. It is a figure which shows the temperature analysis result which concerns on an Example and a comparative example when changing the distance from the outer peripheral edge of the plate part of an inclined fin part.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 4B show a brake disc 1 for a railway vehicle according to an embodiment of the present invention. The brake disc 1 is fastened to both front and back surfaces of a plate portion 20a of a wheel 20 of the railway vehicle, for example, as a fastening member. The bolts 21 and the fastening nuts 22 are detachably attached. The brake disc 1 is made of cast steel, for example.

The brake disc 1 is provided with a donut-shaped plate-shaped plate portion 1a having a circular opening in the center and having a front surface side (outer surface side) as a sliding surface. On the back surface (inside surface) of the plate portion 1a, a plurality of radial fin portions 2 are integrally provided so as to be spaced apart from each other. The brake disc 1 is fastened to the wheel 20 by inserting and fastening the fastening bolts 21 into the bolt insertion holes 2a provided at the middle of the radial fin portions 2 in the longitudinal direction. In this embodiment, twelve radial fin portions 2 are provided on each side surface of the plate portion 20a with a center angle of 30°. The number is not necessarily limited to 12 and may be larger or smaller.

In the present embodiment, for example, three auxiliary fin portions 3 are integrally provided on the plate portion 20a so as to extend radially between the pair of radial fin portions 2. Although the thickness of the auxiliary fin portion 3 is smaller than the thickness of the radial fin portion 2, the number thereof is not necessarily limited and may be larger or smaller.

On the back surface of the plate portion 20a, inclined fin portions 4 are provided so as to project on both sides in the circumferential direction of the radial fin portion 2 at a predetermined inclination angle θ. As will be described later in detail, the inclination angle θ is 30° or more and 50° or less (30°≦θ≦50°). In the present embodiment, one end of the inclined fin portion 4 is connected to the radial fin portion 2, the intermediate portion is connected to one auxiliary fin portion 3, and the other end is connected to the middle auxiliary fin portion 3. .. The inclined fin portions 4 of the adjacent radial fin portions 2 are connected at the same radial direction (longitudinal direction) position of the middle auxiliary fin portion 3 (the same distance Y from the outer peripheral end).

Then, in the pair of brake discs 1, the plate portion 20a of the wheel 20 is sandwiched from both sides in the thickness direction thereof, and the fastening nuts 22 are fastened to the fastening bolts 21 inserted through the bolt insertion holes 2a. It is adapted to be detachably fixed to the wheel 20.

-Example-
In the brake disc 1 as described above, by providing an appropriate heat capacity on the outer peripheral side of the brake disc 1, it is possible to disperse the thermal energy generated during braking and disperse the generated heat to reduce the stress generated in the brake disc 1. It turned out that

In the brake disc 1 as described above, in order to confirm the heat dispersion performance effect of the disc, unsteady heat transfer and stress analysis of FEM analysis were performed.

The applied heat flow rate was set on the condition that a high-speed vehicle with a wheel diameter of 860 mm and 300 km/h was assumed. The result is shown in FIG. The item "front surface" in Fig. 5 refers to the sliding surface on the outer surface side, and the "rear surface" refers to the radial fin portion 2, the auxiliary fin portion 3, and the slope on the side opposite to the sliding surface (inner side surface side). A portion where the fin portion 4 does not exist is shown. Numerical values in the table indicate temperatures (°C). The numbers in parentheses in FIGS. 5 to 8 indicate the rate of decrease relative to the comparative example.

Along with the confirmation of the effect of heat dispersion, the change in stress generated on the sliding surface of the brake disc 1 was confirmed. The result is shown in FIG. It was confirmed that the generated stress had a smaller value than that of the comparative example at an oblique angle of 30° or more and 50° or less. As described above, since the stress generated on the surface was suppressed, it was confirmed that the heat dispersion contributed to the suppression of the generation of thermal cracks.

In addition to the angle θ of the inclined fin portion 4, the thickness X may be affected. Therefore, when the angle θ was 30°, the thickness X of the inclined fin portion 4 was changed to confirm the stress generated on the sliding surface of the brake disc 1. The result is shown in FIG. 7. Here, it was confirmed that the thickness X had almost no effect on the stress.

Furthermore, it is conceivable that the end point or the starting point position of the inclined fin portion 4 influences other than the angle θ of the inclined fin portion 4. Therefore, when the angle θ of the inclined fin portion 4 was 30°, the stress Y generated on the sliding surface of the brake disc 1 was confirmed by changing the distance Y from the outer peripheral end of the inclined fin portion 4. The result is shown in FIG. As can be seen from this, it was confirmed that the distance Y from the outer peripheral edge had almost no effect on the stress.

As described above, when the radial fin portion 2 is connected at an angle smaller than 30°, it is difficult for the inclined fin portion 4 to integrally connect the auxiliary fin portion 3 to the radial fin portion 2. Further, if it is larger than 50°, the heat capacity and the surface area do not reach the area where stress is reduced. However, according to the above-described embodiment, since the inclined fin portion 4 is connected to the heat radiation fin portion 2 at an appropriate angle, an appropriate surface area can be secured and further heat dispersion can be expected.

Note that the above embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its applications, and uses.

1 brake disc
1a Plate part
2 Radial fin section
2a Bolt insertion hole
3 Auxiliary fin section
4 Inclined fin section
20 wheels
20a plate part
21 Fastening bolts (fastening members)
22 Fastening nuts (fastening members)

Claims (1)

A donut-shaped disc-shaped plate having the front surface as a sliding surface,
A plurality of radial fin portions which are radially provided at intervals on the back surface of the plate portion, and which are fastened to the wheel by inserting a fastening member into a bolt insertion hole provided in the middle in the longitudinal direction,
On the back surface of the plate portion, provided with inclined fin portions projecting at respective angles on both sides in the circumferential direction of the radial fin portion,
The brake disc, wherein the inclined fin portion is integrally connected to the radial fin portion at an angle of 30° or more and 50° or less.

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