0001]The present invention relates to a disc brake which is used as a braking device for rail vehicles, in particular, a wheel or rail vehicle brake linings are pressed against the sliding surface of the fixed brake disc to the axle, and the railway vehicle disc brake equipped with the same on. BACKGROUND [0002]Recently, railway vehicles, automobiles, as a braking device for land transportation vehicles such as motorcycles are due to speed and larger vehicles have become much that the disk brake is used. Disc brake is a device for obtaining a braking force by the friction due to sliding between the brake disc and the brake linings. [0003] 　For disc brake for a railway vehicle, a donut-shaped disk-shaped brake disk fixed mounted on wheels or axles, the sliding surface of the brake disc, to generate a braking force by pressing the brake lining by a brake caliper. Accordingly, by braking the rotation of the wheel or axle, to decelerate the moving and the vehicle. [0004] 　In the disc brake, noise brake disk at the time of braking is referred to as a "brake noise" and vibration occurs. Brake squeal is thought to occur to produce the unstable vibration entire brake unit is called "self-excited vibration". Such vibration is caused by the frictional force when pressing the brake lining to the brake disc during braking. The self-excited vibration, changing a steady energy excitation energy at the inside of the system from the outside, a vibration amplitude is increased by vibrating itself. To reduce brake noise, it is necessary to suppress the self-excited vibration generated by the frictional force during braking. [0005] 　Patent Document 1, the brake disc, configured disk brake so as to press the pads is disclosed through the piston. In this disc brake, pads, by the frictional force when it is pressed against the brake disc, moves the trailing side is the downstream side in the rotational direction of the brake disc (touch end side). Thus, the contact area of ​​the piston of the pad, at the trailing side, is larger than the leading side is the upstream side in the rotational direction of the brake disc. Thus, by suppressing the self-excited vibration, there is a brake noise can be suppressed. [0006] 　Figure 1 is a plan view of a brake lining disclosed in Patent Document 2. Brake lining 11 includes a substrate 13, and a plurality of friction members 12 which are distributed in a circumferential direction and the radial direction of the brake disc. Each friction member 12 is attached to the substrate 13 via an elastic member (not shown). Support rigidity of the elastic member is different to the position of the friction member 12 on the substrate 13. With this configuration, there is a brake noise can be suppressed. [0007] 　Patent Document 3 has the same structure as that disclosed in Patent Document 2, two adjacent friction member, linked brake lining is disclosed a plate-shaped member. CITATION Patent Document [0008] Patent Document 1: JP 2002-340056 Patent Publication Patent Document 2: JP 2011-214629 Patent Publication Patent Document 3: JP 2012-251597 JP Summary of the Invention Problems that the Invention is to Solve [0009] 　However, the technique disclosed in Patent Document 1, to be applied to existing vehicles, not only the brake lining must be replaced until the brake caliper that applies a pressing force thereto, the effect on the entire disk brake design range. Therefore, it is very difficult to apply this technique to an existing vehicle. [0010] 　In the configuration of the brake lining in Patent Document 2, the support rigidity of the elastic member, it is necessary to change the position on the back plate, the manufacturing management is complicated. [0011] 　The two friction members in the brake lining of Patent Document 3 are connected by a plate-like member, rotation of the friction member, and it is an object to suppress the variation of the friction coefficient of the respective frictional member. In Patent Document 3, considering for reducing brake noise is not made. [0012] 　It is an object of the invention is to provide a brake lining capable of reducing brake noise, it is easy to apply to existing vehicles, the brake lining is easy to manufacture management, and such brake linings to provide a disc brake with. Means for Solving the Problems [0013] 　Brake lining according to this embodiment is a brake lining which is pressed against the sliding surface of the brake disc fixed to a wheel or an axle of a railway vehicle, 　each of the surface faces the sliding surface of the brake disc, each to each other a plurality of friction members arranged at a gap, 　and a back plate fixed to the back surface of the friction member, 　each friction member, while supporting in the region including the central portion of the friction member, the rear surface of the friction member and a substrate on which a spring member is interposed between the back plate side, 　and two adjacent said friction member pair, said backing plate fixed to the pair of friction members are mutually an integral, 　the width of the back plate in the gap of the friction members together in the set of friction members is greater than a width of said friction member is a brake lining for railway vehicles. [0014] 　Disk brake according to the present embodiment, the brake disc fixed to a wheel or an axle of a railway vehicle, 　is pressed against the sliding surface of the brake disc, with a, and the brake lining, a disc brake. Effect of the invention [0015] 　Brake linings and disc brake of the present invention, it is possible to reduce brake noise, it is easy to apply to existing vehicles, it is easy to manufacture management. BRIEF DESCRIPTION OF THE DRAWINGS [0016] [1] Figure 1 is a plan view of a conventional brake linings. [Figure 2A] Figure 2A is a plan view of a brake lining according to one embodiment of the present invention. [Figure 2B] Figure 2B is a plan view of a pair of friction members and the back plate provided in the brake lining according to one embodiment of the present invention. [Figure 2C] FIG 2C is a B-B sectional view of FIG. 2A. FIG 2D] FIG 2D is a plan view of a pair of friction members and the back plate provided in the brake lining according to another embodiment of the present invention. FIG 2E] FIG 2E is a plan view of a pair of friction members and the back plate provided in the brake lining according to another embodiment of the present invention. [Figure 3A] Figure 3A is a plan view of a pair of friction members and the back plate provided in the brake lining in Example (W / D = 1.32) of the present invention. [Figure 3B] Figure 3B is a plan view of a pair of friction members and the back plate provided on the brake lining of Comparative Example (W / D = 0.40). FIG 3C] Figure 3C is a plan view of a pair of friction members and the back plate provided on the brake lining of Comparative Example (W / D = 0.55). [Figure 3D] Figure 3D is a plan view of a pair of friction members and the back plate provided on the brake lining of Comparative Example (W / D = 0.67). FIG 3E] Figure 3E is a plan view of a pair of friction members and the back plate provided on the brake lining of Comparative Example (W / D = 1). [Figure 4A] Figure 4A is a diagram showing the relationship between W / D and squeal index. [Figure 4B] Figure 4B is a diagram showing a relationship between bending stiffness and squeal index. [Figure 5A] Figure 5A is a perspective view showing the amplitude distribution at the time of braking the brake lining of the embodiment of the present invention. [Figure 5B] Figure 5B is a perspective view showing the amplitude distribution at the time of braking the brake lining of Comparative Example of W / D = 0.55. DESCRIPTION OF THE INVENTION [0017] 　Hereinafter, the brake lining and the disc brakes for railway vehicles of the present invention will be described in detail embodiments thereof. [0018] 　Figure 2A ~ 2C are diagrams showing an example of a railway vehicle disc brake of the present invention. Figure 2A, a plan view of a brake lining, in FIG. 2B, a plan view of a pair of friction members, in Figure 2C, the B-B sectional view of FIG 2A, respectively. 2A and 2B respectively show a state as viewed brake lining, a pair of friction members, from the brake disc side, which is the surface side. [0019] 　Disc brake of the present invention, as shown in Figure 2C, includes a brake disc 1, the brake lining 2, a. Brake lining 2 is attached to a brake caliper (not shown). Brake disc 1 is a donut-shaped disk shape, attached by bolts to a wheel or an axle (not shown) and is firmly fixed. Brake caliper is actuated during braking, it is pressed against the brake lining 2 on the sliding surface 1a of the brake disc 1. Accordingly, friction due to sliding between the brake disc 1 and the brake lining 2 occurs, the braking force is generated. Thus, disc brakes, brake the rotation of the wheel or axle, to decelerate the moving and the vehicle. [0020] 　Brake lining 2 shown in FIGS. 2A ~ 2C are includes a plurality of friction members 3, a back plate 4, the spring member 5, a substrate 6 to hold all of these, the. Friction members 3, each surface faces the sliding surface 1a of the brake disk 1, each of which is arranged at a clearance from one another. Specific sequences of the friction member 3, and the number is not particularly limited. [0021] 　Friction members 3 are sintered copper material, made of a resin material. The friction member 3, as shown in FIGS. 2A and 2B, a planar shape circular, small holes 3a are formed at the center thereof. This is the small hole 3a, the rivet 7 is inserted, the rivet 7, the friction member 3 is attached to the substrate 6. The planar shape of the friction member 3 is not limited to a circular shape, for example, a square, or a polygon such as a hexagon. [0022] 　The back surface of the friction member 3, in order to maintain its strength and rigidity, a back plate 4 made of a thin metal plate such as steel is fixed. Together two friction member 3 adjacent the pair, with respect to the set of the friction member 3, one of the back plate 4 is provided. Backing plate 4 is of the integral over both of the friction member 3 of the pair. Thus, a pair of friction members 3 are in a state of being connected with the back plate 4. [0023] 　Back plate 4, in this embodiment, is oval. In each pair of the friction member 3, the opposite side portions and opposing portions of the friction member 3, the back plate 4 has substantially the same radius of curvature and the friction member 3, the edges and back of the friction member 3 the edges of the plate 4, substantially overlap. Array direction of the pair of friction members 3 for connecting with the back plate 4 is not particularly limited, even those that are arranged in a radial direction of the brake disc 1, even one that arranged in the circumferential direction, except their or may be arranged in the direction. [0024] 　Each friction member 3, together with the back plate 4 is attached to the substrate 6 by rivets 7 inserted through a small hole 3a in the center of each of the friction member 3. That is, the friction member 3 is in the region including the central portion of the friction member 3, by a rivet 7, and is supported by the substrate 6. Between the back plate 4 and the substrate 6 on the back surface side of the friction member 3, the spring member 5 is interposed. Thus, a plurality of friction member 3 is in a state of being individually resiliently supported. As the spring member 5, in Figure 2C, but illustrates a disc spring, it may be employed a leaf spring or a coil spring. [0025] 　According to the disk brake having a brake lining 2 of this structure, the friction member 3 is movable individually. Therefore, it is possible to equalize the brake lining 2 and the contact surface pressure of the brake disk 1 during braking. [0026] 　In addition, by a pair of friction members 3 are in a state of being connected with the back plate 4 integral, as compared with the case not coupled in the back plate, the movement is to be restrained. Therefore, regardless of the running speed of the brake start time, the coefficient of friction between the brake disc 1 and the brake lining 2 can be stabilized. [0027] 　Moreover, a pair of friction members 3, since it is fastened to the substrate 6 by two rivets 7 as a fastening member, not be rotated in situ during braking, slack occurs in the fastening portion of the substrate 6 that the can be prevented. Even if the slack in their fastening portion has occurred, so long as the fastening portions of the two positions is not damaged at the same time, it does not have the friction member 3 落失 immediately. Therefore, it is possible to ensure sufficient durability and reliability of the disc brake. [0028] 　However, the friction member 3, because the position of the rivet 7 just below the center in the supporting point is resiliently supported, never be greatly inclined to the movable contact with the brake disk 1 during braking, the contact surface There were uniformly worn over the entire region, uneven wear does not occur. [0029] 　In the brake lining 2 of the present invention, FIGS. 2A and as shown in FIG. 2B, the back plate 4, which in anchored pair of friction members 3 between the portion corresponding to the gap (i.e., the friction member 3 connecting portion) 4a of the width of each other (hereinafter,. as "connecting portion width") W is greater than the width D of the friction member 3. That is, 1