JP4100297B2 - Brake disc for railway vehicles - Google Patents

Description

  The present invention mainly relates to a brake disk for a railway vehicle (also simply referred to as “disk”), and an object thereof is to suppress the warpage of the disk and the undulation of the sliding surface.

  Block brakes, drum brakes, disc brakes, and the like are used as mechanical braking devices for railway vehicles, automobiles, and motorcycles. In recent years, disk brakes have been frequently used with increasing speed and size of vehicles.

  A disc brake has a structure in which a braking force is obtained by friction between a disc and a brake lining, and is usually fixed to an axle or a wheel by a bolt inserted into a mounting hole provided in an inner peripheral portion or a sliding surface of the disc. Yes. Then, the rotation of the axle or wheel is braked by braking the rotation of the disc, and as a result, the speed of the vehicle is controlled.

  By the way, in a high-speed railway vehicle such as a Shinkansen, the rotational speed and inertial force at the time of a brake load are very large. Therefore, the temperature rise of the disk is remarkably larger than that of a disk for other automobiles and motorcycles. Therefore, the thermal strain accompanying the temperature rise becomes very large.

  The disk tends to expand due to this thermal strain, but the disk is restrained by the mounting hole, and deformation of the disk is restrained by contact with the wheel, so the disk is deformed to the opposite side of the wheel. (Hereinafter referred to as “warping”). This disc warpage becomes uneven in the circumferential direction, and the tendency becomes stronger as the mounting hole is provided in the outer peripheral portion.

  As shown in FIG. 4, when a brake is applied, the lining is pressed against the sliding surface 1a of the disk 1 as indicated by the white arrow. When the disk 1 warps as indicated by the broken line, the disk 1 Since the contact between the lining and the lining becomes uneven, the friction characteristic (braking characteristic) becomes unstable. When the amount of warpage of the disc exceeds a certain limit value, the disc cannot be used.

  Therefore, in actual use, the warpage of the disk is regularly inspected, and the amount of warpage or waviness (the value obtained by subtracting the minimum warpage from the maximum warpage in the circumferential direction of the disk) exceeds the specified value. When this happens, you need to replace the disk.

  As described above, the deformation of the disk is not preferable from the viewpoint of economy because the braking characteristics become non-uniform or the life of the disk is shortened. Therefore, a technique for suppressing the deformation of the disk and extending the life of the disk is required. It has been.

Therefore, in order to extend the life of the disk, for example, the disk is divided into an outer ring having a sliding surface and an inner ring having a bolt mounting portion, and the inner ring fitted to the outer ring is wheeled by a bolt. There is a brake disc configured to be fixed to.
JP 10-318304 A

  However, in order to fit the outer ring and the inner ring, it is necessary to provide a certain gap in the circumferential direction. If this gap is small, the workability deteriorates. On the other hand, if this gap is large, rattling occurs and the braking characteristics of the brake become unstable. Further, since stress is generated in the fitting portion due to repeated braking, it is necessary to design the fitting portion so that sufficient durability is obtained.

  The problem to be solved by the present invention is that the braking characteristic becomes unstable as a result of warping and undulation of the railcar disk due to the brake load.

By optimizing the shape of the disk, the present invention reduces the warpage and undulation of the disk while suppressing the increase in the weight of the disk as much as possible, and makes it possible to make the braking characteristics uniform and extend the life of the disk. Therefore, a railroad vehicle brake disc that is fastened to a shaft or a wheel by a plurality of bolts and is heat-input on one side, and a portion whose thickness is periodically changed at equal intervals on the same circumference of the brake disc. The main feature is that the bolt is fastened at the thin portion of the plate thickness that is provided at least in part and periodically changed . Here, the thin-walled portion refers to a region other than the thickest portion of the plate thickness that is periodically changed, and most preferably a place including the thinnest portion of the plate thickness that is periodically changed. It is better to perform fastening with bolts at this thin portion.

As a brake disk used in a railway vehicle, there are a side disk fastened to a side surface of a wheel and a shaft mount disk fastened to an axle.
The present invention relates to both a side disk and a shaft mount disk. Hereinafter, in this specification, a brake disk (disk) refers to both a side disk and a shaft mount disk.

The brake disc for a railway vehicle of the present invention has a portion in which the thickness of the disc is periodically changed at equal intervals on the same circumference of the disc, and the thin thickness of the periodically changed plate thickness By fastening with bolts at the portion, there is an advantage that warpage and undulation generated in the disk can be effectively reduced while suppressing an increase in the disk weight as much as possible.

  As described above, a single-sided heat input brake disk may warp or swell due to long-term use, and this tendency is particularly remarkable in a vehicle having a high traveling speed.

  The present inventors conducted various experiments and analyzes on such warpage and waviness while changing various conditions. Even when the warpage and waviness occurred, the inner periphery of the disk and the center of the sliding surface It has been found that the outer periphery of the bolt fastening position of the part has a relatively small warp due to the influence of fastening, and the warp deformation tends to be relatively large between the fastening part and the fastening part.

The present invention has been made on the basis of the above knowledge, in order not to become too heavy compared to the conventional brake disc, and to make it difficult to distort compared to the conventional brake disc even when heat is applied, A brake disc that is fastened to an axle or a wheel by a plurality of bolts and receives heat from one side, and its thickness is set on the same circumference of the brake disc 11 as shown in FIGS. A portion periodically changed at equal intervals is provided in at least a part on the same circumference, and fastening with a bolt is performed at a thin portion of the periodically changed plate thickness. is there.

  In the present invention, if the plate thickness t1 of the connecting portion 11b between the fastening portion 11a and the fastening portion 11a is too thick compared to the conventional disk, the weight of the disk becomes too heavy. Has no warpage suppressing effect. Therefore, from the viewpoint of the effect of suppressing warpage, the plate thickness t1 is equal to the plate thickness t2 of the fastening portion 11a having substantially the same thickness as that of the conventional disk having a uniform thickness, as shown in FIGS. It is preferable to be 1.2 times or more (that is, a thin portion). Further, when the plate thickness t1 is 1.5 times or more the plate thickness t2, the effect of suppressing undulation is obtained, which is more preferable. Note that the upper limit value of these t1 / t2 values can be reasonably selected within a range in which the disc weight does not become too heavy.

Further, in the present invention, since the plate thickness t1 of the connecting portion 11b between the fastening portions is made larger than the plate thickness t2 of the fastening portion 11a, the fastening portion 11a and the connecting portion 11b on the back surface 11d side of the sliding surface 11c. the shape of the continuous portion component is curved, straight, may be changed as any stepped but, given the stress generated in the disc during braking, it is desirable to change the curved or straight. Figure 1 shows an example of changing the continuous portion minutes straight.

  Furthermore, these portions whose thickness changes periodically may be configured as one unit, and the units may be arranged at unequal intervals on the same circumference of the brake disc. That is, it suffices that at least a part on the same circumference is provided with the periodic thickness change part. However, it goes without saying that the balance at the time of rotation must be maintained in any case. The disc material may be any material such as cast iron, forged steel, Al-based composite material, or carbon.

  In the present invention, the most important point is that there are the thick and thin portions alternately present at equal intervals when viewed on the same circumference. Therefore, in the present invention, the bolt for fixing the brake disc to the wheel may be provided in the thin portion with the bolt position shifted in the radial direction or the circumferential direction, and the thin portion where the bolt is not fastened. There may be.

  In other words, the bolts do not necessarily have to be attached to all the thin-walled portions, and the bolts do not necessarily have to be attached at regular intervals, but the bolts are attached at regular intervals as shown in FIG. It is needless to say that mounting at a point or a line-symmetrical position is advantageous for strain and stress, and it is more preferable to place it at a point-symmetrical position. Furthermore, it is needless to say that it is most preferable that the periodic thickness changing portions are provided at equal intervals over the same circumference in consideration of balance, stress distribution, and other conditions.

  In particular, when bolts are fastened at the center of the brake disk in the radial direction, preferably when the bolt is centered at the center of the brake disk in the radial direction, both strain and stress are evenly distributed, resulting in durability. Even better. Here, the central portion of the brake disc in the radial direction is centered on a circumference concentric with the outer diameter and inner diameter of the brake disc, which is half the width of the difference between the outer diameter and the inner diameter of the brake disc. For example, it is assumed that it has a permissible range that can be reasonably determined to be near the center portion, which may be approximately the outer diameter or the inner diameter of the bolt that is fastened.

Figure 2 is a schematic sectional view showing a state in which the brake disc for rail vehicles entered the side surface of the railway wheel of the present invention.
In the brake disc 11 of the present invention, only the portion (bolt seat) to be fastened with the bolt 2 has a plate thickness of 18 mm, for example, the same thickness as that of the conventional brake disc, and the other portions have the plate thickness of the fastening portion by the bolt 2 For example, the brake disk 11 is periodically changed at equal intervals on the same circumference so as to be twice as thick (36 mm). And it is fastened to the wheel 3 by the bolt 2 at the radial center in the thin portion.

  In order to confirm the effect of the brake disk of the present invention as described above, FEM analysis was performed on the disk of the present invention. In the FEM analysis, the material constants of forged steel currently used on the Shinkansen were used. In the finite element division, in consideration of symmetry, 1/12 (30 °) of the entire circumference was modeled. The width of the sliding surface of the modeled disk (length in the direction 1 in FIG. 3) is 134 mm.

  The FEM analysis model is shown in Table 1 and FIG. As shown in Table 1, in contrast to the conventional example in which the plate thickness is constant at 18 mm, in the present invention example, the plate thickness between the fastening portions is set to 36 mm, which is twice the plate thickness (18 mm) of the fastening portions. Then, it was gradually increased linearly from the center position of the attachment hole provided in the fastening portion to the center position of the joint portion. The weights of both brake disks are 59.0 kg in the present invention example and 45.7 kg in the conventional example. Note that the positions of the mounting holes are the same in the central portion in the radial direction (direction 1 in FIG. 3).

  The FEM analysis conditions were equivalent to an emergency brake load from 360 km / h, which is faster than the vehicle speed currently in commercial operation. When an emergency brake is applied from 360 km / h, the business vehicle stops after about 130 seconds, so the brake time was set to 130 seconds in the FEM analysis. Moreover, it was set as the conditions which load a brake repeatedly 3 times.

  Table 2 shows the FEM analysis results. The maximum temperature of the brake disc decreased by about 12% to 562.6 ° C. in the example of the present invention compared to 637.8 ° C. in the conventional example. In addition, the maximum amount of warpage of the brake disk was improved by about 26% to 0.025 mm in the present invention example compared to 0.034 mm in the conventional example. The swell amount obtained by subtracting the minimum warp amount from the maximum warp amount was improved by about 23% to 0.0030 mm in the present invention example compared to 0.0039 mm in the conventional example.

  In the above embodiment, the thickness of the fastening portion of the disk is the same as that of the conventional disk. However, it goes without saying that the thickness of the disk fastening portion may be smaller than the thickness of the conventional disk. .

  As described above, the brake disc of the present invention is useful as a brake disc for railway vehicles, automobiles, motorcycles, etc., particularly for vehicles that run at high speed, and is particularly suitable for vehicles that require safety and long life. ing.

It is explanatory drawing of the brake disc of this invention, (a) is 1/4 figure of the whole seen from the sliding surface side, (b) is the figure seen from the back surface side of (a), (c) is (a) ) From the outer peripheral side, (d) is a cross-sectional view taken along line AA in (a), and (e) is a cross-sectional view taken along line BB in (a). It is the typical sectional view showing the state where the brake disk for railway vehicles of the present invention which provided the center of the fastening part by a bolt in the diameter direction center of the brake disk was fastened to the side of a railway wheel. It is a FEM analysis model figure of this invention (a figure) and a prior art example (b figure). It is explanatory drawing of the axial force loaded on the volt | bolt which fixes a brake disc at the time of braking.

Explanation of symbols

2 bolt 3 wheel 11 brake disc 11a fastening portion 11b connecting portion 11c sliding surface 11d back surface

Claims (4)

Is fastened by a plurality of bolts to the axle or wheels, it met brake disc for rail vehicles which is heat input from one side,
It has a part where the plate thickness is periodically changed at equal intervals on the same circumference of the brake disc,
A brake disc for a railway vehicle, wherein fastening is performed by a bolt at a thin portion of the periodically changed plate thickness .   2. The brake disk for a railway vehicle according to claim 1, wherein the fastening portions by the bolts are provided at equal intervals.   The brake disk for a railway vehicle according to claim 1 or 2, wherein the fastening portion by the bolt is provided at a symmetrical position. The brake disc for a railway vehicle according to any one of claims 1 to 3, wherein the fastening portion by the bolt is provided at a radial center portion of the brake disc.

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