JP2000309271A - Metal fitting for cramping brake disk mounted on railway car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a long life of a bolt hole rim portion by relieving the stress generated therein on a disc, by providing a second cramping metal fitting with a bolt portion standing upright on a ring-like flange and a bolt hole through which the bolt portion extending from a first cramping metal fitting penetrate. SOLUTION: Left and right cramping metal fittings 11a, 11b are of the same shape and serve in pairs for cramping use. A bolt hole 16 and a bolt portion 15 are disposed alternately on a flange 14 of the cramping metal fitting 11a or 11b. Then, two disks and a wheel disk are interposed between both of the cramping metal fittings 11a, 11b, and the bolt portion 15 provided on the flange 14 penetrates through the bolt hole 16 on the other cramping metal fitting 11b and fastened by a nut under the condition that the disks are fastened. Since the flange is adapted to correspond to a bolt head or a washer portion, the contact area becomes and surface pressure is reduced. In other words, stress caused by friction force near the bolt hole in the disk is relieved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fastener for fastening a brake disk for a railway vehicle to a wheel.

[0002]

2. Description of the Related Art Block brakes, drum brakes, disc brakes, and the like are used as mechanical braking devices for railway vehicles, automobiles, motorcycles, and the like. 2. Description of the Related Art In recent years, disk brakes have been frequently used as vehicles have become faster and larger. The disc brake has a structure in which a braking force is obtained by friction between a brake disc and a brake lining, and is usually attached to an axle or a wheel by bolts.

[0003] Examples of brake disks used in railway vehicles include side disks and shaft mount disks. The side disc is a brake disc fastened to the side surface of the wheel, and the axle mount disc is a brake disc fastened to the axle. The present invention relates to a side disk. In the following description,
The brake disc (disc) means a side disc.

FIG. 1 is a partial cross-sectional view of a railway wheel equipped with a brake disk. In the figure, reference numeral 1 denotes a wheel, 2 denotes an axle, 3 denotes a disc brake disc, 4 denotes a sliding surface, 5 denotes a rim, 6 denotes a wheel disc, 7 denotes a wheel bolt hole, 8 denotes a disc bolt hole, 9 Is a bolt for fastening the disk to the wheel, and 10 is a nut.

[0005] The sliding surface 4 of the disk 3 is on one side and generates heat, so that a strain is applied in a direction in which the sliding surface 4 side extends, that is, a direction in which the sliding surface 4 is curved in a direction opposite to the sliding surface.
However, since the non-sliding surface side is restrained by the wheel disk 6, compressive thermal stress is accumulated on the sliding surface 4 side, particularly at a portion where the brake pad is in contact, and when the stress exceeds the yield stress of the material, plastic strain is generated. Occurs. When the brake is released, the temperature of the disk 3 decreases, and expansion due to heat is stopped. However, since the disk 3 has yielded to the compression side, the sliding surface 4 contracts, and as shown by the dotted line in FIG. Deforms into a mortar shape on the side (warpage occurs).

[0006] In a high-speed railway vehicle such as a Shinkansen, the rotational speed and inertia force when a brake load is applied are extremely large, so that the temperature rise of the disk is remarkably larger than that of a brake disk for automobiles and motorcycles. Therefore, the thermal strain accompanying the temperature rise also becomes very large. The disk expands due to this thermal strain, but the expansion is restrained by bolts and wheels.
However, local distortion occurs in the bolt hole. Also,
In addition to the stress generated by tightening, the bolts that fasten the disk and the wheel have bending stress due to restraining the torque generated during braking, and tensile stress due to restraining the thermal expansion of the disk in the thickness direction. And bending stress due to the warpage of the disk. These repeated stresses may cause the bolt to break due to fatigue.

[0007]

In order to suppress the damage of the disk due to the above-mentioned thermal stress, for example, Japanese Patent Laid-Open No. 10-3 is disclosed.
Japanese Patent No. 18304 discloses that a conventionally integrated disk is divided into an outer ring having a sliding surface and an inner ring having a bolt attachment portion, the outer ring and the inner ring are fitted, and the inner ring and the wheel are further bolted. Has been proposed. It is stated that by dividing the disk into two, thermal strain on the sliding surface is cut off from the bolted portion of the inner ring, and cracks generated from the bolt holes can be suppressed by using a high-strength material for the inner ring. However, the method disclosed in the above publication cannot reduce the stress applied to the bolt, and the disk is divided into an inner ring and an outer ring. No) may occur.

Japanese Patent Application Laid-Open No. 10-129481 proposes a technique in which a ring-shaped spacer is provided between a fastening bolt and a disc, and the contact area between the disc and the bolt is increased by the spacer. It is stated that the stress at the contact portion is reduced by increasing the contact area, and as a result, the stress generated at the edge of the bolt hole is reduced, and the life of the disk can be extended. However, the method disclosed in the publication has no effect of reducing the stress generated in the bolt, and cannot extend the life of the bolt.

As described above, various stresses are applied to the railway vehicle side disk when a brake is applied. As a result, various stresses are generated in the bolts, and as a result, cracks are generated in the disk bolts, which may lead to breakage.

On the other hand, in recent years, the unsprung load of a vehicle has been reduced,
Improvements in ride comfort and weight reduction of the vehicle body have been promoted, and Al composite materials have been used as disc materials.
Since the material strength of the Al composite disk is inferior to that of the iron-based disk, there is a new problem of reducing stress concentration at the bolted portion.

Further, there is a possibility that the disk fastening bolt may be broken before a predetermined replacement period, and one of the causes may be a possibility that the fastening bolt is incorrectly mounted when the disk is assembled to the wheel. That is, the bolt fastening operation is simple but requires extremely high reliability.

It is an object of the present invention to (1) prolong the life of the bolt hole edge by relaxing the stress generated at the bolt hole edge of the disk, and (2) reduce the stress applied to the bolt. And (3) to increase the reliability of bolt fastening work.

[0013]

Means for Solving the Problems The present inventors have studied various methods for solving the above-mentioned problems, and as a result of accumulating tests, the following findings have been obtained.

(A) When a conventional type disk is fastened, by increasing the diameter of the head portion of the bolt, the diameter of the nut or the washer, the stress concentration around the bolt hole of the disk can be reduced. However, if the diameter of the bolt head, the nut or the washer is too large, it interferes with others.

(B) To prevent a load or stress from concentrating on a specific bolt or a specific bolt hole of a disk,
It is only necessary that the bolts are connected. Considering the above (a), it is preferable to adopt a configuration in which a plurality of bolts are integrated on the annular body as a base.

(C) By integrating a plurality of bolts, there is also an effect of reducing erroneous mounting of the bolts, and the reliability of the fastening operation is improved.

The present invention has been completed based on the above findings, and the gist of the invention lies in the following (1) and (2).

(1) The annular flange has a bolt hole through which a bolt extending from the other fastener is penetrated, and a bolt which penetrates a bolt hole provided in the other fastener. Metal fittings for brake discs for railway vehicles.

(2) A female fastener having a bolt hole through which an annular flange portion penetrates a bolt portion extending from the other fastener, and a male metal tool having a bolt portion which penetrates the bolt hole of the female bracket. A fastener for a brake disc for a railway vehicle, wherein the fastener is a set of fasteners.

[0020]

FIG. 2 is a perspective view showing the appearance of a fastener according to the present invention. FIG. 3 is a longitudinal sectional view showing a state in which a disk is fastened to a wheel using the fastener of the present invention. 2 and 3, the same elements as those in FIG. 1 are denoted by the same reference numerals.

In FIG. 2, the left fastener 11a and the right fastener 11b have the same shape, and the two fasteners are used as a pair for fastening. As shown in the figure, bolt holes 16 and bolt portions 15 are alternately arranged on the flange 14 of the fastener 11a or 11b.

In the state in which the disks are fastened, as shown in FIG. 3, two disks 3 and the wheel disk 6 are sandwiched between the two fasteners 11a and 11b, and the bolt 15 attached to the flange 14 is fastened to the other. Bolt hole 1 of fitting 11b
6 and is fastened with a nut 10.

FIG. 4 is a perspective view showing the appearance of another example of the fastener according to the present invention. In the figure, reference numeral 12 denotes a male fastening fitting, and reference numeral 13 denotes a female fastening fitting. 2 are denoted by the same reference numerals. In FIG. 4, all of the bolt portions 15 are provided on the flange 14 of the male fastener 12.

In the present invention, as shown in FIG. 2, the disk may be fastened as a set of two fastening fittings 11a and 11b, or a set of the male fitting 12 and the female fitting 13 as shown in FIG. May be concluded. 2 has an advantage that the number of types of parts is reduced by making the fasteners 11a and 11b have the same shape. On the other hand, as shown in FIG. 4, the type in which the male mold and the female mold are used as one set has an advantage that the existing automatic fastening device can be used as it is because the bolting is performed from one side.

In the present invention, the following effects can be obtained by integrating the fastening portion between the disk and the wheel by a flange.

(1) Conventionally, the disc and the fastening bolt are in contact only with the bolt head or the washer, but the contact area is increased by using a flange corresponding to the bolt head or the washer as a flange. This has the effect of reducing the surface pressure. That is, the stress caused by the frictional force around the bolt holes of the disk is reduced.

In the conventional bolting method, there is a risk that the individual bolts may be attached to the disk surface in an inclined state, and the bolt head surface or the washer surface may hit one side, and local stress may be applied to the bolt or disk. There is a risk of concentration. When the bolt portion is integrated via a flange like the fastener of the present invention, or when the washer portion is integrated,
The bolt is no longer obliquely attached, and local stress concentration on the disk can be suppressed.

(2) When the bolt portion and the washer portion are integrated by the flange having high rigidity, the surface pressure of the fastening portion of the disk is leveled, and the deformation can be reduced. By this effect, bending stress generated in the bolt portion is reduced. In addition, in the conventional fastening with bolts, there is a possibility that the rigidity of the fastening portion is reduced due to insufficient fastening force. However, the integration of the flange and the bolt portion is less likely to reduce the rigidity.

(3) In the conventional method and the fastening method according to the present invention, there is a certain gap (clearance) between the bolt hole of the disk and the bolt. In the conventional method, some bolts are in contact with the bolt holes, and some are not.
The direction and the direction of the contact between them are arbitrary, even if they are in contact. When a braking force is applied in this state, there are bolts that receive a large load and bolts that have a small load. The situation also changes depending on the braking direction (up or down). Therefore, an excessive load may be generated on a specific bolt.

By integrating the fastening portion via the flange as in the present invention, variation in the mounting position of the bolt portion with respect to the bolt hole at the time of mounting can be suppressed, so that the load on the bolt / bolt hole is leveled. In addition, an excessive stress load on a specific bolt can be reduced. As a result, the life of the disk and the bolt can be extended.

The thickness t of the flange 14 of the present invention shown in FIG.
If the thickness is too thin, the flange may be deformed due to the deformation of the disk due to the brake load, or the bolt portion 15 may be broken. If the plate thickness t is too large, the weight of the flange is increased, and as a result, the weight of the wheel set is increased. 10mm ~ 1 to balance strength and lightness
Particularly good is 5 mm.

If the width W of the flange 14 shown in FIG. 2 is too small, there is a possibility that when a thick disk is used, the binding force with the wheel is reduced, or the bolt portion is broken. If the width W is too large, the flange becomes heavy.
It is good to make it 0 to 150 mm or less.

Regardless of the type of fastener shown in FIG. 2 or the pair of male and female fasteners shown in FIG. 4, the total number of bolts 15 is
If the amount is too small, the restraining force in the thickness direction and the restraining force in the rotating direction when a brake is applied are reduced, and the stress applied to the bolts increases, and the bolts may be broken. If the total number of the bolt portions 15 is too large, the strength of the flange and the disk is reduced. Further, in order to make the fastening force uniform, it is preferable that the bolt portion and the bolt hole portion are arranged at equal positions on the circumference.

[0034]

EXAMPLE Table 1 shows a list of disk fastening methods for which a brake test was performed. The prototype disk used was a forged steel disk material currently used in Shinkansen vehicles. The prototype disks were all 780 mm in outer diameter and 125 mm in sliding surface width.
And

[0035]

[Table 1]

Specimen No. 1 and No. Reference numeral 2 denotes a disk using the fastener according to the present invention. All the flanges of the trial-made fasteners had a thickness of 12 mm and a width of 80 mm.

The test piece No. of the present invention example A disk of the type shown in FIG. 2 was used, but a total of 12 bolts were provided as a pair of metal fittings.

The test piece No. of the present invention example The disk No. 2 used a fastener of a type in which the male type and the female type shown in FIG. 4 were paired, but the male type had 12 bolts.

Specimen No. Reference numeral 3 denotes a disk by a conventional fastening method. Specimen No. 4 is Japanese Patent Application Laid-Open No. 10-3183.
This is a disk according to the technology disclosed in Japanese Patent Application Publication No. 04-2004. Specimen No. Reference numeral 5 denotes a disk according to the technique disclosed in Japanese Patent Application Laid-Open No. Hei 10-129481, which is fastened to the disk via a ring-shaped washer.

Specimen No. For the disks 3 to 5, the number of bolts and the number of bolt holes were set to 12.

An actual brake test was performed using the above five types of disk test pieces. The test conditions were equivalent to a brake load from a speed of 300 km / h. At this time, the disk temperature rises to about 600 ° C. Thereafter, the disk was cooled until the disk temperature became 50 ° C. or less, and then the brake was applied again. This brake load was repeated 100 times.

Table 2 shows the results of the brake test.

[0043]

[Table 2]

Regarding the coefficient of friction, the test piece No. 1 and No. Both the average value and the fluctuation range of the friction coefficient of the test piece No. 2 (Example of the present invention). 3 (conventional example) is almost the same value,
It was found that there was no problem in the friction characteristics of the examples of the present invention.

On the other hand, when comparing the stress applied to the bolt of the conventional example, the test piece No. 4 and no. 5 is specimen N
o. There is almost no difference from 3, and the load on the bolt is not much improved. In contrast, the specimen N according to the present invention
o. No. 1 and No. In the test piece No. 2, the stress of the bolt portion was changed in all the disks. It was found that the stress at the bolt portion was reduced by the fastening with the flange. This effect can be expected to extend the life of the bolt portion.

Next, a test was performed on an Al composite disk. In this test, the forged steel disk test piece No.
1 and test piece No. 1 Three to five fastening methods were used. Each specimen No. Are 1a, 3a to 5a.

As in the case of the forged steel disk, the Al composite disk had an outer diameter of 780 mm and a sliding surface width of 125 mm, and was all manufactured by a casting method. However, the specimen No. The inner ring of 4a was made of forged steel.

In the brake test using the Al composite disk, the emergency brake load from 300 km / h was equivalent to that of the forged steel disk.

Table 3 shows the test results.

[0050]

[Table 3]

As shown in Table 3, when a brake test was performed, the test piece No. 3a and no. In 5a, the crack was generated around the bolt hole of the disk by several times of the brake load, and the test was interrupted.
o. 1a and the test piece No. 1 of the conventional example. No cracks occurred in 4a.

In the conventional test piece No. 3a, no. The stress concentrated in the bolt hole in the bolt fastening of the bolt 5a was changed to the specimen No. 5 of the present invention. In 1a, it is considered that the load was uniformly applied to the contact portion between the flange and the disk, and the stress in the bolt hole was dispersed. On the other hand, the test piece No. 4a, no cracks occurred because a high-strength material was used for the inner ring having a bolt portion.

Specimen No. 1a and No. 1 In 4a, a brake test was subsequently performed to measure the bolt stress or the bolt stress.

As shown in Table 3, the specimen No. In the case of 4a, it was found that the frictional characteristics were not stable, and that it could not be used. On the other hand, the specimen No. In the case of 1a, it was found that the friction characteristics were stable and could be applied as a brake disc. Further, the stress of the bolt portion was also small.

From the above brake test results, it was found that the life of the bolt portion and the bolt can be extended by applying the fastener of the present invention to a disk.

[0056]

By using the fastener of the present invention,
The stress applied to the fastening portion between the disk and the wheel and the fastening bolt can be reduced, and the life of the fastening portion can be extended. Further, the concentration of stress generated in the bolt hole can be reduced, and the life of the disk can be extended. Further, the reliability of the whole wheel is improved because the variation factor of the fastening operation is reduced. The effect is great when the present invention is applied to an Al composite disk.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a railway wheel equipped with a brake disk.

FIG. 2 is a perspective view showing an external appearance of a fastener according to the present invention.

FIG. 3 is a longitudinal sectional view showing a state in which a disk is fastened to a wheel using the fastener of the present invention.

FIG. 4 is a perspective view showing the appearance of another fastening fitting of the present invention.

[Explanation of symbols]

 1: wheel 2: axle 3: disk 4: sliding surface 5: rim 6: wheel disk 7: wheel bolt hole 8: disk bolt hole 9: bolt 10: nut 11, 11a, 11b: fastening fitting 12: male Mold fastening bracket 13: Female fastening bracket 14: Flange 15: Bolt part 16: Bolt hole

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Miyuki Yamamoto 4-33 Kitahama, Chuo-ku, Osaka-shi F-term in Sumitomo Metal Industries, Ltd. 3J058 AA44 AA47 AA53 AA62 AA69 AA73 BA31 BA46 BA51 CB12 BA46 BA51 CB12 CB14 DD02 FA21

Claims (2)

[Claims] 1. A fastener for a brake disk for a railway vehicle, comprising: a first fastener and a second fastener.
The fastener of the bolt that rises on the annular flange,
A bolt hole extending through a bolt portion extending from the second fastener; the second fastener includes a bolt portion standing on an annular flange and a bolt portion extending from the first fastener; A fastener for a brake disk for a railway vehicle, comprising a bolt hole. 2. A fastener for a brake disc for a railway vehicle, comprising a male fastener and a female fastener, wherein the male fastener has a bolt portion standing on an annular flange, The female fastener is provided with a bolt hole through which a bolt extending from the male fastener is passed, the fastener for a brake disc for a railway vehicle.