Disk brake device for railway vehicle

Abstract

Provided is a disc brake device for a railway vehicle capable of suppressing warpage of a brake disc. A disc brake device (1) is provided with a brake disc (2) and a brake lining (4). The brake disc (2) is fastened to s wheel by a plurality of bolts (6) inserted into a plurality of bolt holes (21). The brake lining (4) includes a plurality of sliding member sets (41). Each of the sliding member sets (41) includes an inner circumferential sliding member (42i) and an outer circumferential sliding member (42o). When a projection area (PA) of the inner circumferential sliding member (42i) and the outer circumferential sliding member (42o) formed on a sliding surface (22) of the brake disc (2) is divided into inner circumferential projection areas (PAi) and outer circumferential projection areas (PAo) with a virtual circle (PC) passing through the center of each bolt hole (21) as a boundary, the area of the outer circumferential projection areas (PAo) is larger than the area of the inner circumferential projection areas (PAi).

Description

Disc brake device for railway vehicles

[0001] The present disclosure relates to a disc brake device for a rail vehicle.

[0002] Disc brake devices are widely used as braking devices for railway vehicles. Disc brake devices include a brake disc, a brake caliper, and a brake lining. The brake disc is attached to the wheel and rotates together with the wheel. The brake lining is supported by the brake caliper. When the brake caliper is activated, the brake lining is pressed against the brake disc. Friction between the brake lining and the brake disc brakes the brake disc and the wheel.

[0003] Typically, a brake disc is fastened to a wheel with multiple bolts. The brake disc has an annular shape, with the surface opposite the surface facing the wheel serving as a sliding surface. Meanwhile, a brake lining includes multiple sliding members. The sliding members are attached to a brake caliper via a mounting plate and face the sliding surface of the brake disc. During braking, the sliding members are pressed against the sliding surface of the brake disc. At this time, friction between the sliding members and the sliding surface increases the temperature of the sliding surface. This causes thermal expansion of the sliding surface of the brake disc, and in some cases, plastic deformation occurs. Repeated braking in this manner can cause warping of the brake disc (see, for example, JP 2007-205428 A (Patent Document 1)).

[0004] Typically, brake disc warping occurs when the outer periphery of the sliding surface is closer to the brake lining than the inner periphery. When the amount of brake disc warping increases, excessive load is placed on the bolts fastening the brake disc to the wheel. Furthermore, when the amount of brake disc warping increases, the sliding surface becomes significantly tilted, resulting in uneven contact between the sliding member and the sliding surface during braking. Therefore, it is desirable to suppress brake disc warping.

[0005] Japanese Patent Application Laid-Open No. 2007-205428

[0006] The present disclosure has been made in view of the above-described circumstances, and an object of the present disclosure is to provide a disc brake device for a railway vehicle that can suppress warping of the brake disc.

[0007] The disc brake device for a railway vehicle according to the present disclosure includes a brake disc, a brake caliper, and a brake lining. The brake disc has an annular shape and has a plurality of bolt holes formed circumferentially around the central axis of the brake disc. The brake disc is fastened to a wheel by a plurality of bolts inserted into the plurality of bolt holes, each corresponding to one of the bolt holes. The brake lining is supported by the brake caliper. The brake lining includes a mounting plate and a plurality of sliding member sets. The mounting plate is attached to the brake caliper. One surface of the mounting plate faces the sliding surface of the brake disc. The plurality of sliding member sets are arranged in the circumferential direction of the brake disc on the one surface of the mounting plate. Each of the plurality of sliding member sets includes an inner sliding member, an outer sliding member, a backing metal, an inner elastic member, an outer elastic member, an inner fastening member, and an outer fastening member. The inner sliding member and the outer sliding member are arranged in the radial direction of the brake disc. The inner sliding member and the outer sliding member each have a pentagonal shape in a plan view. The backing metal is fixed to the mounting plate-side surfaces of both the inner sliding member and the outer sliding member. The inner elastic member is disposed between the inner sliding member and the mounting plate. The outer elastic member is disposed between the outer sliding member and the mounting plate. The inner fastening member fastens the inner sliding member to the mounting plate. The outer fastening member fastens the outer sliding member to the mounting plate. In a disc brake device configured as described above, when a projection area formed on the sliding surface by projecting the inner sliding members and the outer sliding members of all of the plurality of sliding member sets onto the sliding surface along the central axis of the brake disc is divided into an inner projection area and an outer projection area with an imaginary circle passing through the centers of each of the plurality of bolt holes as a boundary, the area of ​​the outer projection area is larger than the area of ​​the inner projection area.

[0008] According to the disc brake device for a railway vehicle according to the present disclosure, warping of the brake disc can be suppressed.

[0009] FIG. 1 is a plan view of a disc brake device according to this embodiment. FIG. 2 is a cross-sectional view of the disc brake device shown in FIG. 1 taken along line II-II. FIG. 3 is a cross-sectional view of the disc brake device shown in FIG. 1 taken along line III-III. FIG. 4 is a schematic diagram showing the relative positions of the inner and outer sliding members relative to the brake disc in the disc brake device according to this embodiment. FIG. 5 is a cross-sectional view of an analytical model of a brake disc used in the FEM analysis of the examples. FIG. 6 is a schematic diagram showing the heat input distribution of invention examples 1 to 3. FIG. 7 is a schematic diagram showing the heat input distribution of comparative example 1. FIG. 8 is a schematic diagram showing the heat input distribution of comparative example 2. FIG. 9 is a schematic diagram showing the heat input distribution of comparative example 3. FIG. 10 is a schematic diagram showing the heat input distribution of comparative example 4. FIG. 11 is a cross-sectional view of an analytical model of a brake disc warped by heat input.

[0010] In order to achieve the above object, the present inventors have conducted extensive research and have obtained the following findings.

[0011] To prevent warping of the brake disc, it is necessary to ensure that the temperature of the sliding surface rises uniformly over the entire sliding surface during braking. This is because a uniform temperature rise over the entire sliding surface can prevent local thermal expansion of the sliding surface. However, the temperature rise of the sliding surface occurs when the sliding member comes into contact with the sliding surface. In reality, there are restrictions on the arrangement of the sliding member. Therefore, it is practically difficult to make the amount of heat input from the sliding member to the sliding surface uniform over the entire sliding surface in order to achieve a uniform temperature rise over the entire sliding surface.

[0012] Therefore, taking into consideration that a distribution of heat input occurs on the sliding surface of a brake disc, a heat input distribution that is less likely to cause warping was investigated using FEM analysis. The results are shown below.

[0013] The brake disc has a plurality of bolt holes for fastening the brake disc to the wheel with a plurality of bolts. Each bolt hole is formed on a circumference around the central axis of the brake disc. Specifically, the center of each bolt hole is located on an imaginary circle whose center is the central axis of the brake disc. This imaginary circle is a reference circle for the arrangement of the bolt holes, and is also referred to as the bolt hole pitch circle in design. Hereinafter, this imaginary circle for the arrangement of the bolt holes may also be referred to as the bolt hole pitch circle.

[0014] In a brake disc, when the sliding surface is divided into an outer peripheral region and an inner peripheral region by the pitch circle of the bolt holes, if the heat input to the outer peripheral region is greater than that to the inner peripheral region, warping can be suppressed to the same extent as in the case of a uniform heat input, and excessive temperature rise can also be suppressed. To increase the heat input to the outer peripheral region compared to that to the inner peripheral region, the sliding member should be positioned closer to the outer peripheral side of the sliding surface of the brake disc.

[0015] However, this heat input distribution and the arrangement of the sliding members are determined by the contact state between the brake disc and multiple sliding members. Specifically, to reproduce this heat input distribution, the brake lining needs to have an isobaric structure in which each sliding member is in equal contact with the brake disc. In a brake lining with an isobaric structure, an elastic member such as a spring is placed between each sliding member and the mounting plate. The elastic member ensures that the entire surface of each sliding member facing the brake disc is in equal contact with the brake disc.

[0016] In contrast, for example, in a brake lining with a rigid structure in which each sliding member is fixed to a mounting plate, no elastic member is disposed between each sliding member and the mounting plate. In this case, some sliding members may not contact the brake disc, or only a portion of the sliding member may contact the brake disc. This is due to the following reason: The mounting plate is connected to the brake caliper in a certain area, specifically the central area of ​​the mounting plate. Therefore, the pressing force applied from the brake caliper to the mounting plate acts strongly on the central area of ​​the mounting plate. Therefore, in a brake lining with a rigid structure, the portion of the sliding member that overlaps the central area of ​​the mounting plate is more likely to come into contact with the brake disc.

[0017] In addition, brake linings with a structure similar to the equal pressure structure include a structure in which multiple sliding members are connected by an elastically deformable plate, and this plate is fixed to a mounting plate. In this case, although the pressing force is easily transmitted to the multiple sliding members via the plate, the pressing force is not transmitted evenly to all of the sliding members.

[0018] The disc brake device for a railway vehicle according to the present disclosure has been completed based on the above findings. Hereinafter, embodiments of the present disclosure will be described. In the following description, examples of embodiments of the present disclosure will be described, but the present disclosure is not limited to the examples described below. In the following description, specific numerical values ​​and specific materials may be exemplified, but the present disclosure is not limited to these examples.

[0019] A disc brake device for a railway vehicle according to an embodiment of the present disclosure includes a brake disc, a brake caliper, and a brake lining. The brake disc has an annular shape and has a plurality of bolt holes formed circumferentially around the central axis of the brake disc. The brake disc is fastened to a wheel by a plurality of bolts inserted into the plurality of bolt holes, each corresponding to one of the bolt holes. The brake lining is supported by the brake caliper. The brake lining includes a mounting plate and a plurality of sliding member sets. The mounting plate is attached to the brake caliper. One surface of the mounting plate faces the sliding surface of the brake disc. The plurality of sliding member sets are arranged in the circumferential direction of the brake disc on the one surface of the mounting plate. Each of the plurality of sliding member sets includes an inner sliding member, an outer sliding member, a backing metal, an inner elastic member, an outer elastic member, an inner fastening member, and an outer fastening member. The inner sliding member and the outer sliding member are arranged in the radial direction of the brake disc. The inner sliding member and the outer sliding member each have a pentagonal shape in a plan view. The backing metal is fixed to the mounting plate-side surfaces of both the inner sliding member and the outer sliding member. The inner elastic member is disposed between the inner sliding member and the mounting plate. The outer elastic member is disposed between the outer sliding member and the mounting plate. The inner fastening member fastens the inner sliding member to the mounting plate. The outer fastening member fastens the outer sliding member to the mounting plate. In a disc brake device configured as described above, when a projection area formed on the sliding surface by projecting the inner sliding members and the outer sliding members of all of the plurality of sliding member sets onto the sliding surface along the central axis of the brake disc is divided into an inner projection area and an outer projection area with a boundary of an imaginary circle passing through the centers of each of the plurality of bolt holes, the area of ​​the outer projection area is larger than the area of ​​the inner projection area (first configuration).

[0020] In the disc brake device of the first configuration, the brake lining includes a plurality of sliding member sets. In each sliding member set, an inner elastic member is disposed between an inner sliding member and a mounting plate, and the inner sliding member is fastened to the mounting plate by an inner fastening member. Furthermore, an outer elastic member is disposed between an outer sliding member and the mounting plate, and the outer sliding member is fastened to the mounting plate by an outer fastening member. In this case, the brake lining has an isopressure structure. Therefore, the entire brake disc-side surface of each sliding member is in uniform contact with the sliding surface of the brake disc. Furthermore, in the disc brake device of the first configuration, when the projected areas of the inner sliding member and the outer sliding member formed on the sliding surface of the brake disc are divided into an inner projected area and an outer projected area with a virtual circle (bolt hole pitch circle) passing through the centers of each of the plurality of bolt holes as the boundary, the area of ​​the outer projected area is larger than the area of ​​the inner projected area. In other words, the inner sliding members and the outer sliding members in all of the plurality of sliding member sets are generally disposed closer to the outer periphery of the sliding surface of the brake disc. Therefore, when the sliding surface of the brake disc is divided into an outer periphery region and an inner periphery region by the pitch circle of the bolt holes, the amount of heat input to the outer periphery region can be made larger than the amount of heat input to the inner periphery region. Therefore, the disc brake device of the first configuration can suppress warping of the brake disc to the same extent as in the case of uniform heat input, and can also suppress excessive temperature rise of the brake disc.

[0021] In the disc brake device of the first configuration, the ratio of the area of ​​the outer peripheral projected area to the area of ​​the inner peripheral projected area is preferably 1.10 or more (second configuration), which makes it possible to more effectively suppress warping of the brake disc.

[0022] In the disc brake device of the first or second configuration, preferably, when the heat input to the sliding surface of the brake disc as the inner and outer sliding members slide against the sliding surface of the brake disc during braking is divided into the inner heat input and the outer heat input with the imaginary circle as the boundary, the ratio of the outer heat input to the inner heat input is 1.10 or more (third configuration). In this case, the heat input to the outer region is greater than the heat input to the inner region. This makes it possible to more effectively suppress warping of the brake disc.

[0023] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or equivalent components are designated by the same reference numerals, and redundant description will not be repeated.

[0024] [Disc Brake Device] Fig. 1 is a plan view of a disc brake device 1 according to this embodiment. The disc brake device 1 is used as a braking device for railway vehicles. Referring to Fig. 1, the disc brake device 1 includes a brake disc 2, a brake caliper 3, and a brake lining 4.

[0025] [Structure of the Brake Disc] First, the structure of the brake disc 2 will be described. As shown in FIG. 1 , the brake disc 2 has an annular shape. The brake disc 2 is fastened to the wheel 5 by a plurality of bolts 6. For fastening by the bolts 6, the brake disc 2 has a plurality of bolt holes 21. The bolt holes 21 are provided at intervals along the circumferential direction of the brake disc 2. Specifically, the bolt holes 21 are formed on a circumference about the central axis of the brake disc 2. In other words, the center of each bolt hole 21 is located on an imaginary circle PC whose center is the central axis of the brake disc 2. In other words, the imaginary circle PC passes through the centers of each bolt hole 21. This imaginary circle PC is the pitch circle of the bolt holes 21. Hereinafter, this imaginary circle PC may be referred to as the pitch circle PC of the bolt holes 21.

[0026] The bolts 6 are inserted into the bolt holes 21 to fasten the brake disc 2 to the wheel 5. The brake disc 2 is provided substantially coaxially with the wheel 5. The brake discs 2 are arranged on both sides of the wheel 5, respectively.

[0027] Figure 2 is a cross-sectional view of the disc brake device 1 taken along line II-II shown in Figure 1. Of the brake discs 2 attached to both sides of the wheel 5, only one is shown in Figure 2, with the other not shown.

[0028] 2 , the brake disc 2 has a front surface 22 and a back surface 23. The front surface 22 is the surface facing outward in the thickness direction of the brake disc 2. The front surface 22 is a sliding surface against which a brake lining (not shown) is pressed. Hereinafter, the front surface 22 of the brake disc 2 may be referred to as the sliding surface 22. The back surface 23 faces the side surface of the wheel 5. If the brake disc 2 has a plurality of vertical fins extending radially, the back surface 23 is the top surface of the vertical fins.

[0029] Each bolt hole 21 penetrates the brake disc 2. Each bolt hole 21 includes a large diameter portion 211 and a small diameter portion 212. The diameter of the large diameter portion 211 is larger than the diameter of the small diameter portion 212. The large diameter portion 211 and the small diameter portion 212 are arranged in this order from the front surface (sliding surface) 22 toward the back surface 23 of the brake disc 2.

[0030] The wheel 5 has a plurality of through holes 51. The plurality of through holes 51 are formed in the wheel 5 to correspond to the plurality of bolt holes 21 in the brake disc 2. The brake discs 2 are attached to both sides of the wheel 5. Therefore, the bolt holes 21 in one brake disc 2, the through holes 51 in the wheel 5, and the bolt holes (not shown) in the other brake disc are aligned in order.

[0031] A bolt 6 is inserted into the bolt hole 21 of one brake disc 2, the through-hole 51 of the wheel 5, and the bolt hole of the other brake disc. The head 61 of the bolt 6 is disposed in the large-diameter portion 211 of the bolt hole 21 of one brake disc 2, and a nut (not shown) is disposed in the large-diameter portion of the bolt hole of the other brake disc. The threaded portion of the bolt 6 engages with the threaded portion of the nut, thereby fastening the brake disc 2 to the wheel 5. In the example shown in FIG. 2 , an elastic member 7 is disposed between the head 61 and small-diameter portion 212 of the bolt 6 in the large-diameter portion 211 of the bolt hole 21 of one brake disc 2. This elastic member 7 is, for example, a stack of disc springs. Similarly, an elastic member is disposed between the nut and the small-diameter portion of the bolt hole of the other brake disc.

[0032] [Structure of Brake Lining] Returning to Fig. 1 , the structure of the brake lining 4 will be described. As shown in Fig. 1 , the brake lining 4 includes a mounting plate 40 and a plurality of sliding member sets 41. The brake lining 4 is supported by the brake caliper 3. Specifically, the mounting plate 40 has a generally rectangular shape when viewed from the front. The mounting plate 40 is arranged so as to overlap a portion of the brake disc 2 in the circumferential direction. This mounting plate 40 is attached to the brake caliper 3. The mounting plate 40 is connected to the brake caliper 3 at a central region of the mounting plate 40.

[0033] The plurality of sliding member sets 41 are arranged at intervals in the circumferential direction of the brake disc 2. The plurality of sliding member sets 41 do not have to be arranged completely along the circumferential direction of the brake disc 2, but only need to be substantially lined up in the circumferential direction of the brake disc 2. In the present embodiment, six sliding member sets 41 are arranged in the circumferential direction of the brake disc 2. Each sliding member set 41 includes, as sliding members, an inner circumferential side sliding member 42i and an outer circumferential side sliding member 42o. The inner circumferential side sliding member 42i is arranged on the inner circumferential side of the brake disc 2. The outer circumferential side sliding member 42o is arranged on the outer circumferential side of the brake disc 2. The inner circumferential side sliding member 42i and the outer circumferential side sliding member 42o are arranged at intervals in the radial direction of the brake disc 2.

[0034] The inner sliding member 42i and the outer sliding member 42o are each plate-shaped and pentagonal in plan view. One of the five sides of the inner sliding member 42i is adjacent to the outer sliding member 42o, and this side extends in the circumferential direction of the brake disc 2. One of the five sides of the outer sliding member 42o is adjacent to the inner sliding member 42i, and this side extends in the circumferential direction of the brake disc 2. One of the five vertices of the inner sliding member 42i is located on the opposite side to the outer sliding member 42o, and a corner including this point protrudes radially inward from the brake disc 2. One of the five vertices of the outer sliding member 42o is located on the opposite side to the inner sliding member 42i, and a corner including this point protrudes radially outward from the brake disc 2.

[0035] The shape of both sliding members 42i, 42o in a plan view may be substantially pentagonal. Specifically, the five sides of both sliding members 42i, 42o may be straight or curved. For example, of the five sides of the inner sliding member 42i, two sides extending in the radial direction of the brake disc 2 may be curved to bulge. Of the five sides of the outer sliding member 42o, two sides extending in the radial direction of the brake disc 2 may be curved to bulge. In the example shown in FIG. 1 , the outer sliding member 42o of each of the four sliding member sets 41 arranged in the center and the inner sliding member 42i of each of the two sliding member sets 41 arranged at both ends have two curved sides. Furthermore, in the inner sliding member 42i, corners including each of the five vertices may be rounded. In the outer sliding member 42o, corners including each of the five vertices may be rounded. The shape of each of the sliding members 42i, 42o in a plan view may be, for example, a circle, or a polygon such as a square or a hexagon.

[0036] Each sliding member set 41 includes an inner sliding member 42i and an outer sliding member 42o, and is attached to one surface of the mounting plate 40. This one surface faces the sliding surface 22 of the brake disc 2. The number of sliding member sets 41 is not particularly limited as long as there is more than one. In each sliding member set 41, the size of the outer sliding member 42o in a plan view may be the same as or different from that of the inner sliding member 42i. Furthermore, between the sliding member sets 41, the size of the inner sliding members 42i in a plan view may be the same as or different from each other, and the size of the outer sliding members 42o in a plan view may be the same as or different from each other. 1 , the outer circumferential sliding members 42o of the four sliding member sets 41 arranged at the center and the inner circumferential sliding members 42i of the two sliding member sets 41 arranged at both ends are the same size, and the inner circumferential sliding members 42i of the four sliding member sets 41 arranged at the center and the outer circumferential sliding members 42o of the two sliding member sets 41 arranged at both ends are the same size. Then, for example, in the four sliding member sets 41 arranged at the center, the size of the outer circumferential sliding members 42o is larger than the inner circumferential sliding members 42i.

[0037] The brake lining 4 of this embodiment has a pressure-constant structure. The pressure-constant brake lining 4 will now be described with reference to FIG.

[0038] Fig. 3 is a cross-sectional view taken along line III-III of the disc brake device 1 shown in Fig. 1. As shown in Fig. 3, the sliding member set 41 constituting the brake lining 4 includes, in addition to the inner sliding member 42i and the outer sliding member 42o, a backing metal 43, an inner elastic member 44i, an outer elastic member 44o, an inner fastening member 45i, and an outer fastening member 45o.

[0039] A backing metal 43 is fixed to the surface (back surface) of both the inner circumferential side sliding member 42 i and the outer circumferential side sliding member 42 o facing the mounting plate 40. Specifically, a pair of the inner circumferential side sliding member 42 i and the outer circumferential side sliding member 42 o is connected via the single backing metal 43.

[0040] The inner elastic member 44i is disposed between the inner sliding member 42i and the mounting plate 40. Specifically, the inner elastic member 44i is disposed behind the corresponding inner sliding member 42i, between the backing metal 43 fixed to the inner sliding member 42i and the mounting plate 40. The outer elastic member 44o is disposed between the outer sliding member 42o and the mounting plate 40. Specifically, the outer elastic member 44o is disposed behind the corresponding outer sliding member 42o, between the backing metal 43 fixed to the outer sliding member 42o and the mounting plate 40. Both elastic members 44i, 44o are, for example, disc springs. However, both elastic members 44i, 44o may also be leaf springs, coil springs, or the like.

[0041] The inner fastening members 45i fasten the inner sliding members 42i to the mounting plate 40. Specifically, the inner fastening members 45i are provided at the positions of the centers of gravity of the corresponding inner sliding members 42i. The outer fastening members 45o fasten the outer sliding members 42o to the mounting plate 40. Specifically, the outer fastening members 45o are provided at the positions of the centers of gravity of the corresponding outer sliding members 42o. Both fastening members 45i, 45o are, for example, rivets. The inner sliding members 42i, the backing metal 43, and the inner elastic member 44i are attached to the mounting plate 40 by the inner fastening members 45i. The outer sliding members 42o, the backing metal 43, and the outer elastic member 44o are attached to the mounting plate 40 by the outer fastening members 45o.

[0042] As described above, the brake lining 4 includes a plurality of sliding member sets 41. In each sliding member set 41, an inner elastic member 44i is disposed between an inner sliding member 42i and the mounting plate 40, and the inner sliding member 42i is fastened to the mounting plate 40 by an inner fastening member 45i. Furthermore, an outer elastic member 44o is disposed between an outer sliding member 42o and the mounting plate 40, and the outer sliding member 42o is fastened to the mounting plate 40 by an outer fastening member 45o. In this case, the brake lining 4 has an isobaric structure. Therefore, during braking, when the brake lining 4 moves toward the brake disc 2 due to operation of the brake caliper, the entire surface of each sliding member 42i, 42o facing the brake disc 2 comes into uniform contact with the sliding surface 22 of the brake disc 2.

[0043] [Arrangement of Sliding Members] Figure 4 is a schematic diagram showing the arrangement of the inner sliding member 42i and the outer sliding member 42o relative to the brake disc 2 in the disc brake device 1 of this embodiment. Figure 4 shows a plan view of the brake disc 2. As shown in Figure 4, in the brake disc 2, the sliding surface 22 is divided into an outer region 22o and an inner region 22i, with the pitch circle PC of the bolt holes 21 as the boundary. Furthermore, the inner sliding members 42i and the outer sliding members 42o in all of the multiple sliding member sets 41 are projected onto the sliding surface 22 along the central axis of the brake disc 2, and a projection area PA of the inner sliding members 42i and the outer sliding members 42o is formed on the sliding surface 22. Then, with the pitch circle PC of the bolt holes 21 as the boundary, the projection area PA is divided into an inner projection area PAi and an outer projection area PAo.

[0044] In the disc brake device 1 of this embodiment, the inner circumferential sliding members 42i and the outer circumferential sliding members 42o in all of the plurality of sliding member sets 41 are arranged so that the area of ​​the outer circumferential projection area PAo is larger than the area of ​​the inner circumferential projection area PAi. That is, the inner circumferential sliding members 42i and the outer circumferential sliding members 42o in all of the plurality of sliding member sets 41 are arranged, as a whole, closer to the outer circumferential side of the sliding surface 22 of the brake disc 2. In this case, when the sliding members 42i, 42o slide against the sliding surface 22 during braking and heat is input from the sliding members 42i, 42o to the sliding surface 22, the amount of heat input to the outer circumferential region 22o is greater than the amount of heat input to the inner circumferential region 22i.

[0045] [Effect] In the disc brake device 1 of this embodiment, the brake lining 4 has an isopressure structure. Therefore, the entire surface of each sliding member 42i, 42o facing the brake disc 2 is in uniform contact with the sliding surface 22 of the brake disc 2. Furthermore, the inner sliding members 42i and the outer sliding members 42o in all of the multiple sliding member sets 41 are generally disposed closer to the outer periphery of the sliding surface 22 of the brake disc 2. Therefore, the amount of heat input to the outer periphery region 22o of the brake disc 2 can be made larger than the amount of heat input to the inner periphery region 22i. Therefore, as described above, warping of the brake disc 2 can be suppressed to the same extent as in the case of a uniform heat input, and excessive temperature rise of the brake disc 2 can also be suppressed.

[0046] In the disc brake device 1 of this embodiment, a plurality of sliding member sets 41 are arranged in the circumferential direction of the brake disc 2. Each sliding member set 41 includes, as sliding members, an inner sliding member 42i and an outer sliding member 42o arranged in the radial direction of the brake disc 2. Therefore, each sliding member 42i, 42o has an appropriate size, and can effectively receive the elastic force from each elastic member 44i, 44o. Furthermore, because the inner sliding member 42i and the outer sliding member 42o are connected by the backing metal 43, it is possible to prevent them from falling off or spinning freely.

[0047] In this embodiment, in each sliding member set 41, the inner sliding member 42i and the outer sliding member 42o each have a pentagonal shape in a plan view. In this case, the inner sliding members 42i and the outer sliding members 42o can be arranged in a closely packed manner. This makes it possible to ensure a sufficient contact area between the sliding members 42i, 42o and the sliding surface 22 of the brake disc 2.

[0048] [Preferred embodiment] In the brake lining 4, the inner sliding member 42i and the outer sliding member 42o are preferably arranged so that the ratio of the area of ​​the outer projection area PAo to the area of ​​the inner projection area PAi is 1.10 or more. If the area ratio of the outer projection area PAo to the inner projection area PAi is 1.10 or more, warping of the brake disc 2 can be more effectively suppressed. This area ratio is more preferably 1.20 or more, and even more preferably 1.25 or more. There is no particular upper limit to this area ratio. However, if the area ratio is too large, the temperature of the brake disc will rise locally, causing uneven wear. For this reason, the area ratio is preferably 1.80 or less.

[0049] With respect to the brake disc 2, preferably, when the heat input imparted to the sliding surface 22 of the brake disc 2 by the sliding of the inner sliding member 42i and the outer sliding member 42o on the sliding surface 22 during braking is divided into the inner heat input and the outer heat input with the pitch circle PC of the bolt holes 21 as the boundary, the ratio of the outer heat input to the inner heat input is 1.10 or greater. In other words, preferably, the ratio of the heat input to the outer region 22o to the heat input to the inner region 22i is 1.10 or greater. If the heat input ratio of the outer region 22o to the inner region 22i is 1.10 or greater, the heat input to the outer region 22o is greater than the heat input to the inner region 22i. Therefore, warping of the brake disc 2 can be more effectively suppressed. This heat input ratio is more preferably 1.20 or greater, and even more preferably 1.25 or greater. There is no particular upper limit to this heat input ratio. However, if the heat input ratio is too large, the temperature of the brake disc will rise locally, causing uneven wear. For this reason, the heat input ratio is preferably 1.80 or less.

[0050] Below, an FEM analysis was carried out to confirm the effects of the disc brake device 1 of this embodiment. Fig. 5 is a cross-sectional view of an analytical model of the brake disc 2 used in the FEM analysis of the example. The analytical model shown in Fig. 5 simulates the disc brake device 1 shown in Fig. 1, and the cross section shown in Fig. 5 corresponds to the cross section shown in Fig. 2. The analytical model was composed of a brake disc 2, a bolt 6, an elastic member 7, and a wheel 5. Note that, in consideration of axial symmetry, the analytical model used was a model that was 1 / 2 of the size of the wheel with a brake disc in the axial direction and 1 / 12 of the size of the brake disc in the circumferential direction.

[0051] The brake disc 2 was made to be an elasto-plastic body in order to reproduce thermal deformation. The other components (bolts 6, elastic members 7, and wheels 5) were made to be elastic or elasto-plastic. The element type of each component was a hexahedral primary element. The minimum element size of the brake disc 2 and other components was 0.5 mm. However, the minimum element size of the other components may be larger.

[0052] It was assumed that braking energy equivalent to a predetermined braking condition was applied to the analytical model three times. The braking condition was a sudden stop from a speed of 360 km / h. The initial axial force of the bolt 6 was determined to match the actual brake disc 2.

[0053] Then, in the analytical model of the brake disc 2, a heat input distribution Q was applied to the entire sliding surface 22. Seven conditions were set for the heat input distribution Q. However, the total amount of heat input was the same under all seven conditions. Figures 6, 7, 8, 9, and 10 show the heat input distribution Q under the seven conditions. Figure 6 is a schematic diagram showing the heat input distribution Q of invention examples 1 to 3. Figure 7 is a schematic diagram showing the heat input distribution Q of comparative example 1. Figure 8 is a schematic diagram showing the heat input distribution Q of comparative example 2. Figure 9 is a schematic diagram showing the heat input distribution Q of comparative example 3. Figure 10 is a schematic diagram showing the heat input distribution Q of comparative example 4.

[0054] Referring to FIG. 6 , in Examples 1 to 3, the heat input to the outer peripheral region 22o was greater than that to the inner peripheral region 22i. In this case, the area of ​​the outer peripheral projection region PAo was greater than that of the inner peripheral projection region PAi. Referring to FIG. 7 , in Comparative Example 1, the heat input was uniform. Referring to FIGS. 8 and 9 , in Comparative Examples 2 and 3, the heat input to the outer peripheral region 22o was the same as that to the inner peripheral region 22i. However, as shown in FIG. 8 , in Comparative Example 2, the heat input along the pitch circle PC of the bolt holes 21 was reduced, resulting in a W-shaped heat input overall. As shown in FIG. 9 , in Comparative Example 3, the heat input along the pitch circle PC of the bolt holes 21 was increased, resulting in a V-shaped heat input overall. In Comparative Examples 1 to 3, the area of ​​the outer peripheral projection region PAo was the same as that of the inner peripheral projection region PAi. Referring to FIG. 10 , in Comparative Example 4, the heat input to the outer peripheral region 22o was reduced compared to that to the inner peripheral region 22i. In this case, the area of ​​the outer peripheral projection area PAo is smaller than that of the inner peripheral projection area PAi.

[0055] More specifically, in Examples 1 to 3, the heat input ratio of the outer peripheral region 22o to the inner peripheral region 22i was greater than 1.00. The heat input ratio in Example 1 was 1.70. In this case, the area ratio of the outer peripheral projection region PAo to the inner peripheral projection region PAi was 1.70. The heat input ratio in Example 2 was 1.40. In this case, the area ratio was 1.40. The heat input ratio in Example 3 was 1.20. In this case, the area ratio was 1.20. In Comparative Examples 1 to 3, the heat input ratio of the outer peripheral region 22o to the inner peripheral region 22i was 1.00. In this case, the area ratio of the outer peripheral projection region PAo to the inner peripheral projection region PAi was 1.00. In Comparative Example 4, the heat input ratio of the outer peripheral region 22o to the inner peripheral region 22i was less than 1.00. The heat input ratio in Comparative Example 4 was 0.60. In this case, the area ratio of the outer peripheral projection area PAo to the inner peripheral projection area PAi was 0.60.

[0056] Figure 11 is a cross-sectional view of an analytical model of a brake disc 2 in which warpage occurred due to heat input. In the FEM analysis, the amount of warpage d that occurred in the brake disc 2 was evaluated. The amount of warpage d was defined as the displacement in the thickness direction of the outer periphery of the sliding surface 22. Using Comparative Example 1, which has uniform heat input, as a standard, if the amount of warpage was equivalent to that of Comparative Example 1 or within 15% of the amount of warpage of Comparative Example 1, it was judged to be good (OK). Furthermore, the maximum temperature 6 mm inside from the sliding surface 22 was evaluated. If the maximum temperature did not exceed 700°C, which is specified in the design of the brake disc 2, it was judged to be good (OK).

[0057] The analysis results are shown in Table 1.

[0058]

[0059] The results in Table 1 show the following. When the heat input to the outer peripheral region 22o was greater than that to the inner peripheral region 22i, as in Examples 1 to 3, warping was suppressed and excessive temperature rise in the brake disc 2 was also suppressed. When the heat input to the outer peripheral region 22o was the same as that to the inner peripheral region 22i and the heat input on the pitch circle PC of the bolt holes 21 was smaller, as in Comparative Example 2, suppression of warping was not observed. When the heat input to the outer peripheral region 22o was the same as that to the inner peripheral region 22i and the heat input on the pitch circle PC of the bolt holes 21 was larger, as in Comparative Example 3, the amount of warping was suppressed. However, in the case of Comparative Example 3, excessive temperature rise in the brake disc 2 was observed. When the heat input to the outer peripheral region 22o was smaller than that to the inner peripheral region 22i, as in Comparative Example 4, suppression of warping was not observed.

[0060] The above results demonstrate the effectiveness of the disc brake device 1 of this embodiment.

[0061] The embodiments of the present disclosure have been described above. However, the above-described embodiments are merely examples for implementing the present disclosure. Therefore, the present disclosure is not limited to the above-described embodiments, and can be implemented by appropriately modifying the above-described embodiments within the scope of the present disclosure.

[0062] 1: Disc brake device 2: Brake disc 3: Brake caliper 4: Brake lining 5: Wheel 6: Bolt 21: Bolt hole PC: Virtual circle (pitch circle) 22: Surface (sliding surface) 22o: Outer peripheral region 22i: Inner peripheral region 40: Mounting plate 41: Sliding member set 42i: Inner peripheral sliding member 42o: Outer peripheral sliding member PA: Projected region PAi: Inner peripheral projected region PAo: Outer peripheral projected region 43: Backing metal 44i: Inner peripheral elastic member 44o: Outer peripheral elastic member 45i: Inner peripheral fastening member 45o: Outer peripheral fastening member

Claims

1. A disc brake device for a railway vehicle, comprising: a brake disc having an annular shape, a plurality of bolt holes formed on a circumference around a central axis of the brake disc, the brake disc being fastened to a wheel by a plurality of bolts inserted to correspond to the plurality of bolt holes; a brake caliper; and a brake lining supported by the brake caliper, the brake lining including a mounting plate attached to the brake caliper, one surface of which faces the sliding surface of the brake disc, and a plurality of sliding member sets arranged in the circumferential direction of the brake disc on the one surface of the mounting plate, each of the plurality of sliding member sets being an inner peripheral side sliding member and an outer peripheral side sliding member arranged in the radial direction of the brake disc, the inner peripheral side sliding member and the outer peripheral side sliding member each having a pentagon in a plan view, a backing metal fixed to the mounting plate side surface of both the inner peripheral side sliding member and the outer peripheral side sliding member, an inner peripheral side elastic member arranged between the inner peripheral side sliding member and the mounting plate, a projection area formed on the sliding surface by projecting the inner and outer sliding members of all of the plurality of sliding member sets onto the sliding surface along a central axis of the brake disc, the projection area being divided into an inner projection area and an outer projection area with a boundary of a virtual circle passing through the centers of each of the plurality of bolt holes, the outer projection area having an area larger than an area of ​​the inner projection area.

2. A disc brake device as claimed in claim 1, wherein the ratio of the area of ​​the outer peripheral projection region to the area of ​​the inner peripheral projection region is 1.10 or more.

3. A disc brake device as claimed in claim 1 or 2, wherein, when the amount of heat input given to the sliding surface as a result of the inner sliding member and the outer sliding member sliding against the sliding surface of the brake disc during braking is divided into an inner side heat input and an outer side heat input with the imaginary circle as the boundary, the ratio of the outer side heat input to the inner side heat input is 1.10 or more.

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