Brake shoe for railway vehicle

Abstract

To provide a brake shoe for a railway vehicle capable of keeping braking noise low even when the brake shoe is scraped and worn down.SOLUTION: In one embodiment, the present invention relates to a brake shoe 10 for applying brakes to a wheel 100 of a railway vehicle by sliding against a tread 101, comprises a base metal 5 capable of contacting a holder 15 for pressing the brake shoe against the tread, and a brake shoe body 1 attached to the base metal and capable of sliding against the tread, where a side surface 3 of the brake shoe is bent or inflected so that, when viewed from the front, a portion 3a of the side surface 3 of the brake shoe corresponding to a wear area of the brake shoe is positioned closer to a central axis X of the brake shoe than a straight line Y that is perpendicular to the tread 101 and passes through an area 5a of the surface 51 of the base metal that is in contact with one circumferential end of the holder 15.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a braking wheel for a railway vehicle.

Background Art

[0002] Conventionally, the mechanisms of friction brakes for railway vehicles include a tread type and a disk type, and the tread type is mostly adopted for existing lines. The tread type generates a braking force by pressing the friction surface of the braking wheel against the wheel tread of the railway wheel. The braking wheel is composed of a sliding material made of a metal material such as a cast iron wheel or a sintered wheel. However, there are demerits such as a short service life of the cast iron wheel and frequent replacement, and a high cost of the sintered wheel. Therefore, a synthetic braking wheel having a friction body formed by mixing a friction adjusting material such as carbon powder and iron powder with a synthetic resin, which is a relatively long-life and inexpensive material, as a binder, is used. Patent Document 1 proposes a braking wheel in which a back plate having elasticity and a plurality of blocks are fixed on the back plate with a gap therebetween to reduce braking noise. The applicant of the present application has proposed a braking wheel in which an anti-vibration rubber is provided between a base alloy and a sliding material body to reduce braking noise in Patent Document 2.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the conventional brake shoes for railway vehicles have a problem that the brake noise is still large. The large brake noise is unpleasant for passengers, passengers on the platform, residents along the railway line, etc. In particular, there is a problem that the brake noise becomes large when the brake shoes are worn and thinned, and the remaining thickness of the brake shoes becomes thin.

[0005] In order to solve the above problems, the present invention provides a brake shoe for a railway vehicle that can maintain a low brake noise (noise) even when the brake shoe is worn and thinned.

Means for Solving the Problems

[0006] The present invention is a brake shoe for applying a brake to a wheel of a railway vehicle by slidingly contacting a tread surface of the wheel, including a base metal that can contact a holder for pressing the brake shoe against the tread surface, and a brake shoe body that is attached to the base metal and can slide in contact with the tread surface, When the brake shoe is viewed from the front, a portion of the side surface of the brake shoe corresponding to the worn area of the brake shoe is located closer to the central axis of the brake shoe than a straight line passing through a point where the side surface is bent or refracted so as to be orthogonal to the tread surface and to contact a circumferential end of the holder on the surface of the base metal. The present invention relates to a brake shoe for a railway vehicle.

Effects of the Invention

[0007] The brake shoe for a railway vehicle of the present invention includes a portion where the side surface is bent or refracted toward the central axis so that, when the brake shoe is viewed from the front, a portion of the side surface of the brake shoe corresponding to the worn area of the brake shoe is located closer to the central axis of the brake shoe than a straight line passing through a circumferential end that is orthogonal to the tread surface and contacts the holder on the surface of the base metal. Therefore, it is possible to provide a brake shoe for a railway vehicle that can maintain a low brake noise (noise) even when the brake shoe is worn and thinned.

Brief Description of the Drawings

[0008]

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Embodiments for Carrying Out the Invention

[0009] The brake wheel for a railway vehicle of the present invention (hereinafter sometimes abbreviated as "the brake wheel of the present invention") is a brake wheel for slidingly contacting the tread surface of the wheel of a railway vehicle to apply a brake to the wheel. The brake wheel of the present invention includes a base metal (back plate) and a brake wheel body attached to the base metal and capable of sliding contact with the tread surface. The brake wheel body includes a sliding surface capable of sliding contact with the tread surface of the wheel during use. The brake wheel is held by a holder in the use state, and the holder is disposed on the surface of the base metal (the surface opposite to the surface on the brake wheel body side). When the brake is applied, the sliding surface of the brake wheel is pressed against the tread surface of the wheel by the pressing force from the holder.

[0010] As the material of the brake wheel body, any material conventionally known for use in synthetic brake wheels can be used. For example, it includes a binder material (also called a binding material), a friction material, a filler, etc. Examples of the binder material include thermosetting resins excellent in heat resistance, such as straight phenolic resin, modified phenolic resin, or a mixture thereof. Examples of the friction material, filler, etc. include metal powders such as iron powder, alloy powder (Fe-based alloy, Al-based alloy, Fe powder, etc.), carbon powders such as graphite powder, inorganic particles (Al 2 O 3 、SiO 2 、CaCO 2 、BaSO 4 etc.), fiber sheets, etc. The fiber sheet functions as a reinforcing material, and examples thereof include organic fibers such as steel fiber and aramid fiber, and ceramic fibers. In addition, rubber dust, etc. may be included.

[0011] The brake wheel of the present invention may be a hybrid type brake wheel in which a metal block or a ceramic block is inserted inside the brake wheel body.

[0012] Regarding the composition of the synthetic resin - made brake wheel body preferably applicable in the present invention, as an example, 20 - 30% by volume of a thermosetting resin such as phenolic resin as a binder resin, a total of 3 - 15% by volume of metal powders such as Fe - based alloy, Al - based alloy, alloy powder, etc., 5 - 15% by volume of graphite particles as a friction material, a total of 1 - 10% by volume of organic fibers (such as aramid fiber) and inorganic fibers (such as glass fiber) as a reinforcing material, 20 - 35% by volume of rubber dust, and the above inorganic particles (Al 2 O 3 、SiO 2 、CaCO2、BaSO 4etc.) in a total of 15 to 30% by volume and dust resin of 0 to 10% by volume are mixed and compression molded while being thermoset to form the brake shoe body. The rubber dust, the inorganic particles, and the dust resin are friction modifiers.

[0013] The inventors have noticed that as the brake shoe is worn and abraded during use and the remaining thickness of the brake shoe becomes thin, the braking noise (noise) increases. And the cause of this problem has led to the speculation that it lies in the temporal increase in the portion of the sliding surface of the brake shoe where the pressing force from the holder is difficult to be transmitted and the vibration thereof.

[0014] Here, the "portion where the pressing force is difficult to be transmitted" is the portion outside the straight line passing through the position in the front view of the brake shoe that is orthogonal to the tread surface and in contact with one circumferential end of the holder on the base metal surface (hereinafter also referred to as the "normal line").) (the portion farther from the central axis of the brake shoe than the normal line). The above normal line is also a straight line passing through the position in contact with one circumferential end of the holder on the base metal surface and the center of the wheel.

[0015] Based on this speculation, the inventors have made the shape of the brake shoe such that, when viewed from the front, the portion of the side surface of the brake shoe corresponding to the worn area of the brake shoe is located closer to the central axis of the brake shoe than the normal line, including the portion where the side surface is bent or refracted toward the central axis side, so that there is no "portion where the pressing force is difficult to be transmitted" from the start of use until it is replaced. Thereby, in the brake shoe of the present invention, the braking noise (noise) can be maintained at a low level from the start of use until it is replaced.

[0016] In this application, for convenience of explanation, one of a pair of surfaces orthogonal to the width direction of the vehicle tread surface is defined as the "front" of the brake shoe. When the brake shoe is viewed from the "front", the surfaces located before and after in the circumferential direction (the rotation direction of the wheel) are each defined as the "side surface".

[0017] The "worn area" means an area of the brake wheel body that is expected to be worn down during use. The timing of replacing the brake wheel with a new one varies depending on the user. When the thickness of the unused brake wheel is taken as 100%, the edge on the base metal side of the worn area is often at a position where the thickness from the sliding surface of the unused brake wheel is within the range of 50% or more and 80% or less, and more often within the range of 60% or more and 70% or less. For example, when the thickness of the unused brake wheel is 60 mm, the edge on the base metal side of the worn area is often at a position where the thickness from the sliding surface of the unused brake wheel is within the range of 30 mm or more and 48 mm or less, and more often within the range of 36 mm or more and 42 mm or less.

[0018] The "thickness of the brake wheel" means the length in the same direction as the length direction of the normal line for the integrated body of the base metal and the brake wheel body.

[0019] In one aspect, the brake wheel of the present invention has both side surfaces each including a portion bent or refracted toward the central axis side of the brake wheel. For example, each side surface includes a stepped structure in which a portion corresponding to the worn area of the side surface (hereinafter also referred to as "portion A") is closer to the central axis of the brake wheel than the portion near the base metal (hereinafter also referred to as "portion B").

[0020] The angle θ formed by the straight line parallel to the central axis and the portion A 1 is preferably 0° or more and less than 35° from the viewpoint of keeping the braking sound (noise) low. During use, when the angle θ formed by the portion A and the sliding surface 2 is an acute angle, the possibility of chipping at the corner formed by the sliding surface and the portion A increases. Therefore, from the viewpoints of keeping the braking sound (noise) low and preventing chipping of the corner, the angle θ 1 is preferably greater than 0°, more preferably 5° or more. Also, from the viewpoint of ensuring the worn area, it is preferably 30° or less. Also, from the viewpoint of preventing chipping of the corner, the angle θ formed by the portion A and the sliding surface 2 is preferably greater than 90°, more preferably 97° or more and 134° or less.

[0021] (Embodiment 1) Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 6. Hereinafter, the same reference numerals denote the same parts or the same objects.

[0022] FIG. 1 is a schematic front view of the braking wheel 10 in an embodiment of the present invention, FIG. 2 is a plan view of the braking wheel 10 shown in FIG. 1 as viewed from the base metal side, and FIG. 3 is a cross-sectional view taken along the line III-III' of the braking wheel shown in FIG. 2.

[0023] The braking wheel 10 includes a braking wheel body 1, a base metal (back plate) 5, a mounting portion 6 for a holder, and a receiving portion 7. A U-shaped groove portion 4 is formed in the central portion of the braking wheel body 1. Due to the presence of the groove portion 4, the braking wheel 10 has flexibility and is prevented from being damaged due to stress concentration. Since the sliding surface 2 of the braking wheel 10 has a symmetric relationship centered on the central axis X of the braking wheel body 1, the same sliding contact effect can be obtained regardless of whether the railway vehicle travels in either of the two directions.

[0024] FIG. 4 shows a state in which the braking wheel 10 is pressed against the tread surface 101 of the wheel 100 by the holder 15, and FIG. 5 is a partially enlarged view thereof. As can be clearly seen from FIGS. 4 and 5, in the contour of the braking wheel 10 when viewed from the front, each side surface 3 of the braking wheel 10 includes a portion bent or refracted toward the inside of the braking wheel, and includes a portion (portion A) 3a corresponding to the worn area R, a portion near the base metal (portion B) 3b, and a stepped portion 3c between the portion 3a and the portion 3b. Each side surface 3 includes a stepped structure in which the portion 3a is closer to the central axis X than the portion 3b. In FIG. 5, Rr is the end of the worn area R on the base metal side.

[0025] The stepped portion 3c bends inside (on the central axis X side of the braking wheel 10) from the normal line Y passing through the point 5a in contact with one circumferential end of the holder 15 on the surface 51 of the base metal 5 and perpendicular to the tread surface 101. And since the portion 3a is parallel to the central axis X, the entire portion 3a is located inside (on the central axis X side of the braking wheel 10) of the normal line Y. Therefore, the angle θ 1 is 0°.

[0026] FIG. 6 is a schematic front view of the used anti-skid wheel 10 of the present embodiment. As can be seen from FIG. 6, even when the anti-skid wheel 10 is worn and thinned with use, the entire sliding contact surface 2 of the anti-skid wheel body 1 is located inside the normal line Y (on the center line X side with respect to the normal line Y). Therefore, the anti-skid wheel 10 of the present embodiment can maintain a low braking sound (noise) throughout the entire period from the start of use to replacement.

[0027] (Embodiment 2) Next, another embodiment of the present invention will be described with reference to FIGS. 7 to 12.

[0028] FIG. 7 is a schematic front view of the anti-skid wheel 10 in another embodiment of the present invention, FIG. 8 is a plan view of the anti-skid wheel 10 shown in FIG. 7 as viewed from the base metal side, and FIG. 9 is a cross-sectional view taken along line VIII-VIII' of the anti-skid wheel shown in FIG. 8.

[0029] The anti-skid wheel 10 of an embodiment of the present invention shown in FIGS. 7 to 12 has a portion (portion A) 3a corresponding to the worn area R in the side surface 3, and an angle θ formed by a straight line Z parallel to the central axis X of the anti-skid wheel 1 is the same as the anti-skid wheel 10 of Embodiment 1 where each angle θ 1 is 0°, and the same member numbers are assigned to the same parts or the same objects and the description thereof is omitted. In FIG. 11, Rr is the end on the base metal side of the worn area R.

[0030] Figure 10 shows the brake shoe 10 being pressed against the tread 101 of the wheel 100 by the holder 15, and Figure 11 is an enlarged partial view thereof. As can be clearly seen from Figures 10 and 11, in the outline of the brake shoe 10 viewed from the front, each side surface 3 of the brake shoe 10 includes a portion bent or refracted toward the inside of the brake shoe, and includes a portion (portion A) 3a corresponding to the worn area R, a portion near the base metal (portion B) 3b, and a stepped portion 3c between the portion 3a and the portion 3b. Each side surface 3 includes a stepped structure in which the portion 3a is closer to the central axis X than the portion 3b. The portion (portion A) 3a of the side surface 3 corresponding to the worn area R is inclined so as to move away from the central axis X as it moves away from the sliding contact surface 2, and is inclined at an angle θ of 28° with respect to a straight line Z parallel to the central axis X (see Figure 7). Therefore, the angle θ formed by the portion 3a and the sliding contact surface 2 is 102.5°, which is greater than 90°, and during the use of the brake shoe 10, the risk of chipping at the corner formed by the sliding surface 2 and the portion 3a is reduced. 1 The angle θ formed by the portion 3a and the sliding contact surface 2 2 is 102.5°, which is greater than 90°, and during the use of the brake shoe 10, the risk of chipping at the corner formed by the sliding surface 2 and the portion 3a is reduced.

[0031] In addition, the brake shoe of the present invention may be in a mode in which a vibration isolator is disposed between the base metal and the brake shoe body. As the vibration isolator, for example, those described in JP-A-2018-179211 can be used.

[0032] The present application further discloses the following method of using a brake shoe for a railway vehicle.

[0033] <1> A method of using a brake shoe for braking a wheel by slidingly contacting the tread of a wheel of a railway vehicle, the method comprising: the brake shoe including a base metal that can contact a holder for pressing the brake shoe against the tread, and a brake shoe body attached to the base metal and capable of slidingly contacting the tread; rotating the wheel while pressing the brake shoe against the tread with the holder. When viewing the brake wheel from the front, a portion of the side surface of the brake wheel corresponding to the worn area of the brake wheel is located closer to the central axis of the brake wheel than a straight line passing through a point that is orthogonal to the tread surface and in contact with one circumferential end of the holder on the surface of the pedestal. A method of using a brake wheel for a railway vehicle, wherein the side surface is bent or refracted. <2> When viewing the brake wheel from the front, the pedestal-side end of the worn area is at a position within a range where the thickness from the sliding surface of the unused brake wheel is 50% or more and 80% or less when the thickness of the unused brake wheel is taken as 100%. The method of using a brake wheel for a railway vehicle according to <1>. <3> Due to the side surface being bent or refracted, the side surface includes a stepped structure in which the portion corresponding to the worn area of the side surface is closer to the central axis than the portion near the pedestal. The method of using a brake wheel for a railway vehicle according to <1> or <2>. <4> When viewing the brake wheel from the front, the angle formed by a straight line parallel to the central axis and the portion of the side surface corresponding to the worn area is 0° or more and less than 35°. The method of using a brake wheel for a railway vehicle according to <1> or <2>.

Example

[0034] The present invention will be described using the following examples. The present invention is not construed as being limited to the following examples.

[0035] (Example 1) Three brake wheels shown in FIGS. 1 to 3 were manufactured. In Table 3, they are designated as brake wheels A, B, and C for the sake of distinction. The overall size is the straight-line length L when viewed from the front 1 is 350 mm, L 2 is 260 mm, L 3 is 310 mm, the thickness L of the brake wheel 4 is 60 mm, L 5 is 20 mm, and the width L 6 is 79 mm. θ 1 is 0°, θ 2 is 76°. The thickness of the worn area R (see FIG. 5) is 40 mm, corresponding to 67% of 100% of the thickness of the unused brake wheel.

[0036] The material (composition) of the brake wheel body is as shown below. These were mixed and molded in a mold under pressure and heat according to a conventional method to be integrated with the base metal. The pressure and heat conditions were 150 to 170 °C, about 40 to 60 tons / piece, and about 20 minutes. With the following material composition, the Rockwell hardness (HRR) after pressure and heat molding was set to 50 to 90.

[0037] ·Binder resin: Thermosetting phenolic resin 23.6% by volume ·Metal powder: Fe-based alloy, Al-based alloy, and Fe powder, total 9.8% by volume ·Graphite: Graphite powder 5.9% by volume ·Reinforcing material: Aramid fiber and inorganic fiber, total 2.9% by volume ·Friction modifier: Rubber dust 30.6% by volume, inorganic particles (Al 2 O 3 , SiO 2 , CaCO2, BaSO 4 ), total 21.7% by volume, dust resin 5.5% by volume

[0038] (Example 2) Two brake wheels shown in FIGS. 7 to 9 were manufactured. In Table 4, they are designated as brake wheels A and B for distinction. The overall size is such that the straight-line length L 1 is 350 mm when viewed from the front, L 2 is 260 mm, L 3 is 310 mm, the thickness L 4 of the brake wheel is 60 mm, L 5 is 20 mm, and the width L 6 is 79 mm. θ 1 is 28°, θ 2 is 102.5°. The thickness of the worn area R (see FIG. 11) is 40 mm, corresponding to 67% of the thickness of the unused brake wheel, which is 100%. The material of the brake wheel body is the same as that in Example 1.

[0039] (Comparative Example 1) Three brake wheels 60 shown in FIG. 13 were manufactured. In Table 5, they are designated as brake wheels A, B, and C for distinction. The overall size is such that the straight-line length L 1is 350 mm, L 2 is 260 mm, L 3 is 310 mm, the thickness of the brake wheel L 4 is 60 mm, and the width is 79 mm. The material of the brake wheel body is the same as that in Example 1. Figure 14 is a front view of the brake wheel 60 of Comparative Example 1 after the test.

[0040] Using the brake wheels of Examples 1 to 2 and Comparative Example 1, a vehicle driving test was conducted under the conditions shown in Table 1 below, and the brake noise was measured. The noise was measured using a noise meter (TYPE 7312) manufactured by ACO Co., Ltd., and the sound (skid sound) in the high-frequency range (1000 - 8000 Hz) was measured. The noise meter was installed at a location 5 m away from the wheel. Each brake wheel was tested 3 times.

[0041]

Table 1

[0042] [Evaluation Criteria for Brake Noise] Maximum: 109 dB or more Large: 101 dB or more Medium: 95 dB or more Small: 86 dB or more Minute: 76 dB or more

[0043]

Table 2

[0044]

Table 3

[0045]

Table 4

[0046]

Table 5

[0047] As can be seen from the comparison between Table 3 and Table 4, and between Table 4 and Table 5, it can be understood that for the brake wheels of Example 1 and Example 2, the brake noise (noise) can be maintained lower than that of the brake wheel 60 of Comparative Example 1. Regarding the unused brake wheel 60 of Comparative Example 1, as shown in Fig. 13, for the portion near the sliding surface 62 of the side surface 61, it is on the center line X side of the brake wheel rather than on the normal line Y side. Therefore, for a while after the start of use, no brake noise (noise) occurs, and even if it occurs, it is small. However, as the brake wheel 60 is worn and abraded, as shown in Fig. 14, the portion of the sliding surface 62 located outside the normal line Y (the portion where the pressing force by the holder is difficult to be applied) increases. In addition, combined with the fact that the thickness of the brake wheel is also becoming thinner, it is speculated that the portion W of the brake wheel located outside the normal line Y vibrates and the brake noise (noise) becomes large.

Industrial Applicability

[0048] The brake wheel for railway vehicles of the present invention can maintain a low brake noise (noise) even when it is worn and abraded, so it can reduce the discomfort of passengers, passengers on the platform, residents along the railway line, etc., and is useful.

Explanation of Signs

[0049] 1 Brake wheel body 10 Brake wheel 2 Sliding contact surface 3 Side surface 3a Tread side portion 3b Base metal side portion 3c Step portion 4 Groove part 5 Base metal (back plate) 5a Location where it is orthogonal to the tread surface and contacts one circumferential end of the holder on the surface of the base metal 51 Surface of the base metal 6 Attachment part 7 Receiving part 15 Holder 100 Wheel 101 Tread surface X Central axis of the braking wheel Y Straight line (normal line) passing through the location where it is orthogonal to the tread surface and contacts one circumferential end of the holder on the surface of the base metal Z Straight line parallel to the central axis X of the braking wheel θ 1 Angle formed by the straight line Z parallel to the central axis X of the braking wheel and the part corresponding to the worn area on the side surface θ 2 Angle formed by the part corresponding to the worn area on the side surface and the sliding surface

Claims

1. A wheel brake for applying a brake to a wheel by slidingly contacting a tread surface of the wheel of a railway vehicle, comprising: a base metal that can contact a holder for pressing the wheel brake against the tread surface, and a wheel brake body attached to the base metal and capable of slidingly contacting the tread surface; When the wheel brake is viewed from the front, a side surface of the wheel brake is bent or refracted such that a portion of the side surface corresponding to the worn area of the wheel brake is located closer to the central axis of the wheel brake than a straight line passing through a point where the side surface is orthogonal to the tread surface and contacts a circumferential end of the holder on the surface of the base metal. A wheel brake for a railway vehicle.

2. When the wheel brake is viewed from the front, an end on the base metal side of the worn area is located within a range where the thickness from the sliding surface of the unused wheel brake is 50% or more and 80% or less when the thickness of the unused wheel brake is 100%. The wheel brake for a railway vehicle according to Claim 1.

3. Due to the side surface being bent or refracted, the side surface includes a stepped structure in which a portion of the side surface corresponding to the worn area is closer to the central axis than a portion near the base metal. The wheel brake for a railway vehicle according to Claim 1 or 2.

4. When the wheel brake is viewed from the front, an angle formed by a straight line parallel to the central axis and a portion of the side surface corresponding to the worn area of the side surface is 0° or more and less than 35°. The wheel brake for a railway vehicle according to Claim 1 or 2.

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