JP5126903B2 - Fastening structure of railcar brake disc and railcar wheel axle - Google Patents

Description

  The present invention improves the fatigue reliability of bolts used for fastening brake discs and can withstand long-term use, and a brake disc fastening structure for a railway vehicle, and the brake disc using the fastening structure. The present invention relates to a railcar wheel shaft that has been fastened.

  Block brakes, drum brakes, disc brakes, etc. are used as braking devices for land transport machines such as railway vehicles, automobiles, and motorcycles. Recently, disc brakes have been used more frequently due to higher speeds and larger vehicles. It has come to be.

  A disc brake is a device that obtains a braking force by friction between the two generated by pressing a brake lining against a rotating brake disc. Usually, a braking force is obtained by pressing a brake lining against a sliding surface of a donut-shaped disk-like disk attached to an axle or a wheel by a bolt, and the speed of the vehicle is controlled by braking the rotation of the axle or the wheel. A disk-shaped disk having this sliding surface is called a brake disk.

  Among these brake discs, railcar brake discs include a side disc and a shaft mount disc. Among these, the side disc is a brake disc fastened to the side surface of the wheel, and the shaft mount disc is a brake disc fastened to the axle via a disc body.

  Hereinafter, in this specification, the term “brake disk” refers to both a side disk and a shaft mount disk, and refers to a sliding surface that exists only on one side of the brake disk.

  FIG. 7 shows the shape of a conventional rail car side disk, wherein (a) is a radial-circumferential plan view showing a quarter of the brake disk, and (b) is a radial-axial sectional view. As shown to the figure (a) (b), generally the brake disc 1 is from the sliding part 2 provided with the sliding surface 2a on one side, and the fastening part 3 provided with the bolt insertion hole 3a for fastening to a wheel. It is configured. Although not shown, in the sliding portion 2 of the brake disc 1, fins for heat dissipation are often provided on the surface that contacts the wheel on the opposite side of the sliding surface 2a.

  FIG. 8 is a radial-axial cross-sectional view schematically showing a state in which a conventional brake disk for a railway vehicle is attached to a wheel. As shown in the figure, the brake disc 1 is fastened to both sides of the wheel 4 by bolts 5a, nuts 5b, and washers 5c, which are fastening members, and is attached to rotate integrally with the wheel 4.

  A brake lining 6 that can move toward and away from the sliding surface 2a is attached at a position facing the sliding surface 2a of the brake disc 1, and the brake lining 6 approaches the brake disc 1 side during braking. The vehicle is moved and tightly squeezed from both side surfaces of the wheel 4, and the vehicle is stopped by braking the rotation of the axle through the wheel 4 by this frictional force.

By the way, in a high-speed railway vehicle such as the Shinkansen, the rotational speed and inertial force of the brake disk are very large, so that the temperature increase of the brake disk during braking is significantly increased. For this reason, the following problems occur due to thermal deformation of the brake disc.
1) A large bending stress is generated in the fastening bolt.
2) Cracks, deformations, and depressions occur at the periphery of the brake disc bolt insertion hole.

  As a technique aimed at solving such a problem, a brake disk fastening structure shown below is disclosed.

  For example, in Patent Document 1, when using a brake disk made of an aluminum-based composite material having a sliding surface on one side, it is possible to suppress cracking / deformation of the peripheral edge of the bolt insertion hole due to thermal expansion during braking. An intended fastening structure is disclosed.

  Specifically, as shown in FIG. 9, the sliding portion 2 and the fastening portion 3 of the brake disk 1 are divided so that the connecting portion between them is a gear-like meshing shape, and the axial direction when viewed from the wheel of the connecting portion. This is a fastening structure in which an annular body called a corrugated leaf spring 7 is inserted outside.

  With this fastening structure, it is expected that the bolt 5a will not restrain the radial expansion of the brake disc 1 due to frictional heat, and that a high-strength material can be used only for the fastening portion, and the above goal is achieved.

  In Patent Document 2, when using a brake disk made of an aluminum composite material having a sliding surface on one side, especially when the brake disk material is soft with respect to fastening parts such as bolts, nuts, and washers. A fastening structure for the purpose of preventing a fastening part from biting into a brake disk fastening surface and generating a crack is disclosed.

  Specifically, as shown in FIG. 10, a plurality of bolt insertion holes are provided between the head of the bolt 5a, the nut 5b, the fastening surface of the brake disc 1, and the fastening surface of the wheel 4 and the brake disc 1. A fastening structure in which a ring-shaped spacer 8 is inserted.

  By adopting such a fastening structure, it is aimed to reduce the surface pressure generated on the fastening surface of the brake disk when the brake disk is fastened using fastening parts such as bolts.

  Further, in Patent Document 3, a sliding surface is provided on both sides of a brake disc made of light metal, and when a brake disc that is fastened to a hub fitted to an axle is used, it occurs on the sliding surface of the brake disc during braking. There has been disclosed a fastening structure that makes it difficult to transmit the heat to the hub and suppresses a decrease in grasping force with respect to the axle of the hub.

  Specifically, as shown in FIG. 11, between the fastening surface of the brake disc 1 and the hub 11, and between the fastening surface of the brake disc 1 and an annular body called a tightening ring 9 provided on the surface opposite to the hub 11. Further, a thin plate member 10 called an insulating washer, an insulating plate, or an insulating ring is inserted into the fastening structure.

  By adopting such a fastening structure, heat generated on the sliding surface of the brake disk during braking becomes difficult to be transmitted to the hub, and the aim is to achieve the purpose of suppressing a decrease in grasping force with respect to the axle of the hub. .

  By the way, in recent years, the braking load increases as the speed of the vehicle increases, and a high stress is generated in the bolt used for fastening the brake disc and the wheel. An increase in the generated stress of the bolt leads to an increase in the possibility of fatigue damage of the bolt. Therefore, it is a problem to improve the fatigue reliability of the disk fastening portion including the bolt.

  In order to improve the fatigue reliability of the brake disc fastening part, two methods of improving the fatigue strength of the bolt and the brake disc itself or improving the structure of the fastening part to reduce the stress generated in the bolt and the brake disc. Can be considered.

  The technique disclosed in Patent Document 1 employs both techniques, and the techniques disclosed in Patent Documents 2 and 3 employ the latter technique.

  However, in the fastening structure disclosed in Patent Document 1, since the sliding portion and the fastening portion of the brake disk are divided, the shape of the connecting portion is complicated. In addition, since the brake disc is an aluminum-based composite material, the corrugated leaf spring inserted between the bolt head or nut and the connecting portion has a leaf spring function in order to reduce the surface pressure during bolt fastening. Therefore, the labor and cost of production increase. Furthermore, if the sag of the corrugated leaf spring occurs during use, the axial force of the bolt decreases, and excessive stress fluctuations may occur in the bolt, causing damage.

  Moreover, like the fastening structure disclosed in Patent Documents 2 and 3, inserting an annular body into the bolt and brake disk fastening surface is effective in reducing the contact surface pressure and suppressing heat conduction. In terms of reducing the generated stress of the bolt, it is considered that the effect cannot be expected for the following reason.

  That is, due to non-uniform frictional heat generation on the brake disk sliding surface and non-uniform friction coefficient on the contact surface between the brake disk and the wheel or hub, the brake disk axis and the wheel or hub axis are Deviation occurs between In this case, an excessive stress may be generated on the bolt on the side where the radial displacement of the brake disk is increased with respect to the wheel or the hub.

JP-A-10-129480 Japanese Patent Laid-Open No. 10-129481 Japanese Patent No. 4092007

  The problem to be solved by the present invention is to improve the fatigue reliability of the brake disk fastening portion, particularly the fatigue reliability of the bolt, in order to cope with the increase in braking load accompanying the recent increase in vehicle speed. It is a point.

  The inventors conducted numerical analysis on the fastening structure between the brake disc for a railway vehicle and the wheel and assumed repeated braking, and obtained the following knowledge as a result of repeated research.

(1) When the brake disc expands radially outward due to frictional heat during braking, the bolt stem comes into contact with the inner surface of the wheel or the bolt insertion hole of the disc body, causing bending, so that the fluctuation in stress acting on the bolt is large. Become.

(2) The stress fluctuation acting on the bolt increases as the radial displacement increases.
(3) Due to repeated braking, misalignment occurs between the axis of the brake disc and the wheel or disc body.

(4) The phenomenon of (3) is caused by non-uniform frictional heat generation on the sliding surface of the brake disk and non-uniform friction coefficient on the contact surface between the brake disk and the wheel or hub. It is estimated that the radial displacement is not constant depending on the circumferential position. For this reason, an excessive stress may be generated in the bolt at the circumferential position where the radial displacement is large.

(5) Even if braking is repeated when the inner peripheral surface of the annular body inserted between the fastening parts such as bolts, nuts and washers and the brake disc fastening portion is fitted to the boss portion of the wheel or disc body, There is no misalignment between the annular body and the wheel or disk body. Further, the bolt is not displaced in the radial direction due to the thermal expansion of the brake disc during braking. Therefore, it is possible to greatly reduce the stress fluctuation acting on the bolt.

The fastening structure of the railway vehicle brake disc of the present invention is made based on the above knowledge,
In order to improve the fatigue reliability of the brake disc fastening part, especially the bolt fatigue reliability,
A fastening structure for fastening a brake disc using bolts and nuts to both sides of a wheel or both sides of a disc body fitted and fastened to an axle,
The bolt insertion hole provided in the fastening part of the brake disc, and the bolt insertion hole provided at the same position as the bolt insertion hole provided in the fastening part of the wheel or the disc body with the brake disc, The main feature is that an annular body whose surface is fitted to the wheel or the boss portion of the disc body is arranged outside the brake disc fastening portion and fastened with a bolt and a nut.

  The railcar wheel axle of the present invention in which the brake disc fastening structure for a railcar vehicle of the present invention is used and the brake disc is fastened to both sides of the wheel or both sides of the disc body fastened to the axle is long-term. Even when used, it is possible to prevent problems due to fatigue damage of the brake disc fastening portion.

  In the present invention, when the brake disc and the wheel or the axle are fastened, the fatigue reliability of the fastening portion of the brake disc, particularly the bolt, can be improved, so that the braking load increases as the speed of the vehicle such as the Shinkansen increases. However, it is possible to prevent problems due to fatigue damage of the brake disk fastening portion.

It is the figure which showed the model of the conventional shape used for the numerical analysis by a finite element method, (a) is a perspective view, (b) is a side view. It is a figure which shows typically the deformation | transformation of the brake disc and bolt at the time of braking obtained as a result of the numerical analysis by a finite element method. It is the figure which showed the model used for the numerical analysis of this invention fastening structure, (a) is a perspective view, (b) is a side view. BRIEF DESCRIPTION OF THE DRAWINGS It is the figure which showed the fastening structure of the brake disc for railways of this invention, (a) is radial direction-axial direction sectional drawing of the principal part, (b) is radial direction-circumferential direction top view which shows 1/4 of a brake disc. It is. It is a figure which shows the brake disc and annular body shape of the model which analyzed, (a) is invention example 1, (b) is invention example 2, (c) is invention example 3, (d) is a comparative example. . It is a model figure used for the numerical analysis by the finite element method which evaluates the influence of the clearance gap between the internal peripheral surface of a cyclic | annular body, and the boss | hub part of a wheel, (a) is radial direction-circumferential direction which shows 1/2 of a brake disc A plan view, (b) is a radial-axial sectional view. The shape of the conventional railway vehicle side disk is shown, (a) is a radial-circumferential plan view showing 1/4 of the brake disk, and (b) is a radial-axial sectional view. It is a radial direction-axial direction sectional view showing typically the state where the conventional brake disk for rail vehicles was attached to the wheel. It is the figure which showed the fastening structure of the brake disk for rail vehicles disclosed by patent document 1, (a) is a perspective view of a sliding part, (b) is a perspective view of a fastening part, (c) is a sliding part. The perspective view of the state which connected the fastening part, (d) is a perspective view of a corrugated leaf | plate spring, (e) is sectional drawing which follows the AA line of (c) figure. (A) is a principal part perspective view of the fastening structure of the brake disk for rail vehicles disclosed by patent document 2, (b) is AA sectional drawing of (a) figure. FIG. 5 is a cross-sectional view of a main part of a fastening structure for a railway vehicle brake disc disclosed in Patent Document 3;

  In the present invention, for the purpose of improving the fatigue reliability of the brake disc fastening portion, in particular, the bolt, an annular body having a fitting structure with the boss portion of the disc body fastened by fitting the inner peripheral surface to a wheel or an axle. Has been realized by arranging it outside the brake disc fastening portion.

Hereinafter, the present invention will be described in detail with reference to FIGS.
In order to clarify the stress generated in the bolt during braking in the initial stage of research, the inventors developed a model of a structure in which the brake disk 1 having the conventional shape shown in FIG. 1 is fastened to the wheel 4 by the bolt 5a. The numerical analysis by the finite element method (FEM) was performed.

  As a result of the numerical analysis, as schematically shown in FIG. 2, when the temperature rises during braking, the brake disk 1 deforms into a convex shape and expands radially outward, so that bending stress is generated in the bolt 5a. I understood that. It was also found that the bending stress was distributed from the constricted part 5aa of the bolt 5a to the threaded part 5ab and the part facing the outer peripheral side of the brake disk 1 was highly stressed.

  The bending stress generated in the bolt is generated forcibly pressing the brake disk that is thermally deformed. Therefore, in order to reduce the bending stress generated in the bolt, the thermal deformation of the brake disc is reduced, the rigidity against the deformation of the brake disc is reduced, or a load is not applied to the bolt even if the brake disc is deformed. Is considered effective.

  It has been found that the former two can be realized by increasing the thickness of the sliding portion of the brake disk and decreasing the thickness of the fastening portion. The inventors have paid attention to a structure in which a load does not act on the bolt even if the brake disk, which is the last measure, is deformed.

  The inventors insert an annular body having a bolt insertion hole at the same position as the bolt insertion hole of the fastening portion between a fastening part such as a bolt, a nut, and a washer, and a fastening portion of the brake disk, and this annular body. It was considered that the inner peripheral surface of the disc is fitted to the outer periphery of the boss portion of the wheel or disk body. And the numerical analysis by the finite element method was performed using the model of the fastening body by the brake disc 1-wheel 4-bolt 5a-annular body 12 shown in FIG.

  This is a model based on the fastening structure shown in FIG. 4, in which the symmetry is taken into account in the region of 1/2 in the axial direction and the region in the circumferential direction of 15 ° in consideration of the periodicity. is there. The diameter of the inner peripheral surface of the annular body 12 in FIG. 3 and the diameter of the outer peripheral surface of the boss part of the wheel 4 are the same size in order to simulate the fit.

  Using this model, first, 150 kN per bolt is applied as an axial force to the bolt 5a to reproduce the fastening state, and then the amount of heat corresponding to braking until the sliding surface 2a of the brake disk 1 stops from 275 km / h. And then allowed to cool.

  The stress range obtained by extrapolating to the threaded portion 5ab based on the stress range in the constricted portion 5aa provided between the threaded portion 5ab and the trunk portion 5ac of the bolt 5a and the bending moment distribution and tensile load in the trunk portion 5ac. Table 1 below shows the radial displacement amount of the brake disc 1 at the center position of the screw portion 5ab of the bolt 5a. Table 1 below also shows a comparison of analysis results obtained using the conventional shape model shown in FIG.

  The stress range shown in Table 1 is the amount of change during braking of the axial stress at the part facing the outer peripheral side of the brake disc 1. The reason for setting the outer peripheral side of the brake disk 1 is that the bending stress generated in the bolt 5a by braking is generated so that the outer peripheral side becomes high stress.

  From Table 1, it can be seen that in the fastening structure of the present invention in which the annular body 12 is inserted, the stress range in the constricted portion 5aa of the bolt 5a is greatly reduced. This is because in the case of the fastening structure of the present invention, the bolt 5a is not displaced in the radial direction of the brake disc 1 during braking. Furthermore, it can be seen that the stress range obtained by extrapolating to the threaded portion 5ab that may actually cause fatigue damage is similarly reduced.

  In the above numerical analysis, the frictional heat generation on the sliding surface of the brake disc is uniform in the circumferential direction of the brake disc, and the friction coefficient of the contact surface between the brake disc and the wheel or hub is also uniform. When expanding and contracting radially outward, the brake disk's radial displacement is exactly the same at each position in the circumferential direction, that is, the brake disk, wheel, pitch circle diameter of the bolt fastening position, and the respective axes remain the same. It is assumed that.

  However, when the braking test was actually repeated, it was found that the brake disc and the wheel shaft were gradually displaced, and the bolt insertion position changed slightly from the initial state.

  This phenomenon is caused by non-uniform frictional heat generation on the sliding surface of the brake disc and non-uniform friction coefficient on the contact surface between the brake disc and the wheel or hub. It is estimated that it is caused by the fact that it is not constant depending on the circumferential position. For this reason, in the case of the conventional shape of FIG. 11, excessive stress may be generated in the bolt at the circumferential position where the radial displacement is large.

  Furthermore, although two brake discs are disposed on both sides of one wheel, the two discs do not necessarily exhibit the same deformation behavior. Even when the radial displacements of the brake discs on both sides are different, excessive stress fluctuations may occur in the bolt.

  This behavior is not limited to the conventional fastening structure shown in FIG. 11, and even if an annular body is inserted between the fastening parts and the fastening surface of the brake disc, the annular body is misaligned with respect to the wheel. Any structure that is not constrained by movement can occur.

  Therefore, the annular body needs to be constrained with respect to the wheel so that the axis does not always deviate. Therefore, in the fastening structure of the present invention shown in FIG. The disc body has a structure that fits with the outer periphery of the boss 4a.

  Since this fitting portion only needs to be sufficiently smaller than the radial displacement of the conventional bolt shown in Table 1, the intermediate portion defined in Japanese Industrial Standard JIS B0401 is commonly used for fitting of bearings and the like. Or a clearance fit. For example, in the case of an intermediate fit, the inner peripheral surface of the annular body is H7, and the outer peripheral surface of the boss portion of the wheel is h7. In the case of clearance fit, the inner peripheral surface of the annular body is H7, and the outer peripheral surface of the boss part of the wheel is g7.

The fastening structure of the railway brake disk of the present invention is made based on the above analysis results,
A fastening structure for fastening a brake disc using bolts and nuts to both sides of a wheel or both sides of a disc body fitted and fastened to an axle,
The bolt insertion hole provided in the fastening part of the brake disc, and the bolt insertion hole provided at the same position as the bolt insertion hole provided in the fastening part of the wheel or the disc body with the brake disc, An annular body having a surface fitted to the wheel or the boss portion of the disc body is arranged outside the brake disc fastening portion and fastened with a bolt and a nut.

  In addition, the above-described brake disc brake disk fastening structure of the present invention is used, and the brake disc is fastened to both sides of the wheel or both sides of the disc body fastened to the axle. It is.

Below, the analysis result performed in order to confirm the effect of this invention is demonstrated.
Table 2 below shows the details of the analyzed model shape.

  The invention examples have three types of shapes, and the invention examples 1 and comparative examples are the same as those shown in Table 1 above. Inventive Examples 2 and 3 have a shape in which the plate thickness tr of the annular body is made thinner than that of the Invention Example 1, and the plate thickness tb of the fastening portion of the brake disk is increased instead.

  Each brake disc has an outer diameter of 725 mm, and the pitch circle diameter of the bolt insertion hole of the fastening portion is 385 mm, which is the same for all models. The wheels and bolts all use the same shape model.

  5A to 5D show shapes of the brake disc 1 and the annular body 12 of the inventive examples 1 to 3 and the comparative example. These models also model an area of 15 ° in the circumferential direction in consideration of the periodicity as described above. Further, the diameter of the inner peripheral surface 12b of the annular body 12 and the diameter of the outer peripheral surface of the boss portion 4a of the wheel 4 are set to the same size in order to simulate the fit.

  The measured values of steel materials used as conventional products were used for the physical properties and strength characteristics of the disks, bolts, and wheels used in the analysis. First, an axial force equivalent to 150 kN per bolt is given to the bolt, and then the temperature distribution obtained by giving a heat quantity equivalent to the kinetic energy when braking is applied on the sliding surface from the initial speed of 275 km / h, and its temperature distribution The thermal stress was analyzed based on the change.

  Table 2 also shows a comparison of the stress range of the constricted part of the bolt obtained by analysis. This stress range is the amount of change during braking of the axial stress at the portion of the constriction that faces the outer peripheral side of the brake disk. The reason why the outer peripheral side of the brake disk is set is that the bending stress generated in the bolt during braking is generated so that the outer peripheral side becomes high stress.

  From Table 2, it can be seen that in any of Invention Examples 1 to 3, the bolt generation stress is reduced by 50% or more compared to the comparative example. When the inventive examples 1 to 3 were compared, the stress range of the bolt tended to increase as the plate thickness of the annular body was reduced. However, even if the plate thickness of the annular body was 4 mm, the bolt was compared with the comparative example. It can be seen that the stress range is significantly reduced.

  However, although not shown in Table 2, since the stress generated in the annular body itself tends to increase as the plate thickness of the annular body decreases, the strength of the material used for the annular body depends on the plate thickness. Must be selected.

  In addition, the annular model used in the invention example is provided with only bolt insertion holes, but it is necessary to allow cooling air to pass through the gap between the wheel and the fin side of the brake disc or to fit the wheel hydraulic fit. A hole or notch for inserting a hydraulic hose may be provided.

  Next, in order to confirm the effectiveness of fitting the inner peripheral surface 12b of the annular body 12 with the outer periphery of the wheel 4 or the boss 4a of the disc body, a finite element is used using the model shown in FIG. Numerical analysis by the method was performed.

  The model shown in FIG. 6 is obtained by extending the 15 ° model shown in FIG. 3 to 180 °. There are two types of models of the annular body 12 in which the diameter of the inner peripheral surface 12b is changed, and the gaps with the bosses 4a of the wheels 4 are 0.0 mm, 0.1 mm, and 0.5 mm, respectively. .

  In the numerical analysis, an axial force of 150 kN was applied to the bolt 5a, and a forced displacement was applied so that the brake disk 1 moved 0.7 mm in a direction parallel to the symmetry plane as indicated by the white arrow in FIG.

  This analysis condition is based on the assumption that the brake disc 1 and the wheel 4 may be misaligned due to a considerable number of braking loads applied over a long period of time. It was set with the intention of evaluating the stress.

  Table 3 below shows the amount of increase in stress at the outer peripheral side constricted portion of the evaluation bolt (the bolt on the right side of the paper, which is hatched in FIG. 6).

  From Table 3, the bolt stress does not change at all when the gap between the inner peripheral surface of the annular body and the wheel boss is 0.0 mm, but the bolt stress increases as the gap increases to 0.1 mm and 0.5 mm. It can be seen that the amount is increasing.

  From the above, it can be seen that the gap between the inner peripheral surface of the annular body and the boss portion of the wheel is preferably as small as possible. However, considering the ease of assembly, the gap between the inner circumferential surface of the annular body and the boss of the wheel is realistic to have an intermediate fit or a clearance fit as defined in JIS B0401. It can be said.

  By the way, the clearance amount of the intermediate fit, which was mentioned earlier as an example of the fitting structure, with the inner peripheral surface of the annular body being H7 and the outer peripheral surface of the wheel boss being h7 is 0.00 to 0.10 mm, The clearance amount of the clearance fit, in which the inner peripheral surface of the body is H7 and the outer peripheral surface of the boss part of the wheel is g7 is 0.01 to 0.12 mm.

  As described above, an annular body having a bolt insertion hole is inserted at the same position as the bolt insertion hole provided in the fastening part of the brake disc between the fastening parts such as bolts, nuts and washers and the brake disc fastening part. It can be concluded that it is effective to reduce the bolt-generated stress and improve the fatigue reliability of the disk fastening part including the bolt by making the inner peripheral surface of the body fit with the wheel or the outer periphery of the boss part of the disk body.

  The present invention is not limited to the above example, and it goes without saying that the embodiment may be appropriately changed within the scope of the technical idea described in each claim.

  For example, in the above example, the brake disc material was analyzed as a steel material, but the present invention is considered to be effective for other materials such as an aluminum composite material. In the above example, the member on which the brake disc is fastened with a bolt is called a wheel. However, the same effect can be obtained by using this as a disc body fitted to the axle and used as a shaft mount disc.

  The present invention described above is not limited to a brake disk for a railway vehicle, but can be applied to a brake disk for an automobile, a motorcycle, or the like.

DESCRIPTION OF SYMBOLS 1 Brake disc 2 Sliding part 2a Sliding surface 3 Fastening part 3a Bolt insertion hole 4 Wheel 4a Boss part 5a Bolt 5b Nut 5c Washer 6 Brake lining 12 Ring body 12a Bolt insertion hole 12b Inner peripheral surface

Claims (2)

A fastening structure for fastening a brake disc using bolts and nuts to both sides of a wheel or both sides of a disc body fitted and fastened to an axle,
The bolt insertion hole provided in the fastening part of the brake disc, and the bolt insertion hole provided at the same position as the bolt insertion hole provided in the fastening part of the wheel or the disc body with the brake disc, An annular body having a surface fitted to the wheel or the boss portion of the disc body is disposed outside the brake disc fastening portion and fastened with a bolt and a nut. Fastening structure.   A railcar wheel axle characterized in that the brake disc fastening structure according to claim 1 is used and the brake disc is fastened to both sides of the wheel or both sides of a disc body fastened to the axle.

Images