JP7209440B2 - Cushioning member for railroad vehicle shaft coupling and railroad vehicle shaft coupling - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cushioning member used in a shaft coupling that transmits rotation of a motor, which is a part of a drive system for a railroad vehicle, to a gear box, and a railroad vehicle shaft coupling. More specifically, the present invention relates to a cushioning member that can be used in various shaft couplings such as gear type and flat plate type shaft couplings, and to a railway vehicle shaft coupling.

A joint is provided between the motor fixed to the bogie and the gearbox that is integrated with the axle, and it is designed to absorb the ups and downs of the car body and the phase shift during meandering (see, for example, Patent Document 1). ).

In the case of a gear-type flexible shaft coupling, it is composed of a pair of inner (external gear) members that are fitted with the motor shaft and the small gear shaft of the gear device, and an outer cylinder (internal gear member) that meshes with the external gear and is freely variable. A partition called a center plate is provided so that the inner members do not collide with each other when displaced in the axial direction or the vertical direction. In addition, the inner member is provided with a cushioning member made of synthetic rubber at a position facing the center plate in order to absorb the impact when it comes into contact with the center plate.

JP 2001-65589 A

However, in the case of this type of railroad vehicle shaft coupling, the displacement of the joint causes the cushioning member and the center plate to come into contact with each other at different distances from the center (locations with different radii). The center plate is scratched. Moreover, the joints of railway vehicles rotate at high speeds exceeding 5000 rpm, for example, and are used under severe conditions such as being subjected to high loads. For this reason, the cushioning member is strongly struck and rubbed against the center plate for each rotation, and the surface of the cushioning member may be worn in a pitted manner. This wear phenomenon is particularly noticeable in mountainous areas with many curves and in high-speed vehicles. If this wear becomes excessive, the inner member and the center plate will come into direct contact with each other, and there is a danger that the inner members will collide with each other, leading to an accident.

An object of the present invention is to improve the durability of a cushioning member for a railroad vehicle shaft coupling. Another object of the present invention is to provide a railroad vehicle shaft coupling that can reduce the replacement frequency of the cushioning member and reduce the wear of the center plate.

A damping member for a railroad vehicle shaft coupling that achieves such an object includes a pair of opposed inner members provided at respective shaft ends of a drive shaft and a driven shaft that face each other on the same axis, and surrounds the pair of inner members. A cushioning member for a railroad car shaft coupling comprising an outer member engaged with each of the inner members in the direction of rotation transmission, and a center plate fixed to the outer members and disposed between the inner members, wherein the inner member or the center plate and a sliding portion having a surface in contact with a mating member in which a relative speed difference of the elastic portion is caused is covered with a sheet of a low-friction material.

Here, the sheet of low friction material is preferably polytetrafluoroethylene.

Moreover, it is preferable that the elastic portion is made of synthetic rubber.

Further, a shaft coupling for a railway vehicle of the present invention includes the cushioning member according to any one of claims 1 to 3 .

Further, in the railroad vehicle shaft coupling, it is preferable that the contact portion of the center plate with the cushioning member is coated with a low-friction material.

According to the cushioning member for a railroad vehicle shaft coupling according to the present invention, since the frictional force at the time of contact is reduced, the durability of the cushioning member is improved, and the replacement frequency of the cushioning member can be reduced. In addition, according to the cushioning member for a railroad vehicle shaft coupling according to the present invention, it is possible to reduce wear of the center plate.

1 is a central longitudinal sectional view showing an embodiment of a buffer member for a flexible joint according to the present invention; FIG. 1 is a central longitudinal sectional view showing an embodiment of a railroad vehicle shaft coupling according to the present invention; FIG. FIG. 5 is a central vertical cross-sectional view showing another embodiment of the railroad vehicle shaft coupling according to the present invention. It is a front view which shows the test result of the buffer member of the flexible shaft coupling concerning this invention, (A) shows the state before a test, (B) shows the state after a test. FIG. 10 is a front view showing a state of deterioration of a cushioning member of a conventional flexible joint.

Hereinafter, the configuration of the present invention will be described in detail based on the embodiments shown in the drawings.

FIG. 1 shows an example of an embodiment of a cushioning member for a railroad vehicle shaft coupling of the present invention. The cushioning member 1 according to this embodiment is in contact with an elastic portion 2 having elasticity attached to the inner member or the center plate of the shaft joint for railway vehicles and a counterpart member in which the relative speed difference of the elastic portion 2 occurs. and a sliding portion 3 whose surface is covered with a low-friction material 4 .

The cushioning member 1 of the present embodiment is mounted on, for example, the upper surface of the fastening nut of the inner member facing the center plate of the shaft joint for railway vehicles, and has an annular shape with four arcuate corners. It has a substantially rectangular cross section, and the elastic part 2 is fitted into an annular recess around the screw hole on the upper surface of the hexagonal nut so that the sliding part 3 protrudes from the upper surface of the nut toward the center plate. It is what is done. The shape of the cushioning member 1 is not particularly limited to the annular shape shown in the drawing, and it can take any appropriate shape according to the structure, shape, etc. of the mating member to which the annular member 1 is attached. For example, a cap structure that covers the upper surface of the fastening nut and the shaft end surface of the male screw may be used, and the plane shape may be polygonal, rectangular, circular, or various other shapes. Furthermore, even when the cushioning member 1 is attached to the center plate, it is not limited to a specific shape, and may be formed in various shapes such as a flat disc shape, a polygonal shape, and a rectangular shape. Alternatively, depending on the circumstances, it may be formed as an annular ring or a polygonal ring. Furthermore, not only the surface in contact with the mating member where the relative speed difference occurs, but also the area outside the surface may be formed into a film to cover the entire surface of the center plate.

The elastic portion 2 is intended to reduce the impact of contact between the drive shaft side member and the driven shaft side member of the railroad vehicle coupling, and is required to have appropriate cushioning properties. In this embodiment, a solid ring member made of nitrile rubber is used. As a result, a stable elastic force can be obtained over a long period of time due to the rubber elasticity of the material itself, and the durability of the cushioning member 1 is improved. Of course, the elastic portion 2 may be made of other synthetic rubber material or elastic resin material. Moreover, the elastic part 2 may have structural elasticity by adopting not only the elastic force of the material, but also a shape with a hollow inside, a shape with a bellows-like wall portion, or the like.

As the low-friction material 4 forming the sliding portion 3, various synthetic resins generally having lower friction than synthetic rubber materials can be used. For example, as plastic sliding materials, fluororesins such as polyacetal (POM), polyamide (PA), and polytetrafluoroethylene (PTFE, trade name Teflon (registered trademark) of DuPont) are generally used. It is also possible to use polyphenylene sulfide (PPS), elastomers, polyolefins, thermosetting resins, and other super engineering plastics. The friction coefficient of polytetrafluoroethylene is about 0.04, which is about 1/20 of the friction coefficient of about 0.9 of the synthetic rubber of the elastic portion 2, and sufficient friction characteristics are obtained. Further, for example, nylon has a coefficient of friction of about 0.24, and is expected to be more effective than synthetic rubber. On the other hand, in the sliding part 3, the contact pressure of the used part is extremely high, and a large frictional force is generated. effect is needed. For this reason, it is preferable that the low-friction material 4 constituting the sliding portion 3 has excellent frictional characteristics and appropriate hardness and flexibility. For this reason, it is preferable to use a fluororesin. Examples of fluororesins include polytetrafluoroethylene (PTFE), tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene/hexanefluoropropylene copolymer (FEP), tetrafluoroethylene/ Examples include ethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), etc. Among them, use of PTFE is preferred.

The sliding portion 3 is preferably a low-friction material 4 covering the elastic portion 2 . For example, among fluororesins, polytetrafluoroethylene (PTFE) coatings are preferred. The PTFE coating can be formed by, for example, coating the elastic portion 2 to form a thin film (Teflon coating), or by attaching a sheet (Teflon sheet) of solidified molding powder by adhesion or the like, but it can be formed by coating. Since the thickness of the thin film is limited and the durability is somewhat inferior, it is preferable to attach a sheet that can secure a sufficient thickness. Furthermore, since PTFE is prone to wear and creep, when it is used as a sliding material, fillers such as glass fiber, graphite, bronze, carbon fiber, molybdenum disulfide, special fillers, etc. are mixed and used. is preferred. Wear resistance can be further improved by combined use of solid lubricants, oxides, and the like.

Here, the greater the thickness of the Teflon sheet, the more advantageous it is for wear, but if it is too thick, the elasticity of the cushioning member cannot be obtained, and the cushioning effect is reduced. Therefore, it is preferable to set the thickness to an appropriate thickness, for example, 1 mm or less.

The sliding portion 3 is the entire circumference of the surface that contacts the mating member where the relative speed difference of the elastic portion 2 occurs (that is, the surface that faces the center plate in the case of this embodiment in which the cushioning member 1 is attached to the inner member). Although it is preferable to form it continuously in the circumferential direction, it may be formed discontinuously in the circumferential direction depending on the case. For example, a plurality of sliding portions 3 may be discontinuously arranged at regular intervals in the circumferential direction on the surface of the annular elastic portion 2, that is, the surface that contacts the mating member on which the relative speed difference occurs. Alternatively, the cushioning member 1 itself may be discontinuous, for example, molded into a block shape and arranged in an annular shape on a surface that may come into contact with a mating member that produces a relative speed difference.

The cushioning member 1 constructed as described above reduces the frictional force when the sliding portion 3 comes into contact with a mating member that causes a relative speed difference. Since a high friction reduction effect can be obtained, a long-term friction reduction effect can be obtained. For this reason, if the cushioning member of this embodiment is applied to, for example, a gear-shaped flexible joint for railway vehicles, the replacement frequency of the cushioning member 1 can be reduced.

FIG. 2 shows an embodiment of a flexible joint to which the cushioning member of this embodiment is applied. A flexible shaft coupling 11 according to this embodiment is a gear-shaped flexible shaft coupling for railway vehicles, and includes a drive shaft (for example, a motor shaft) 12 and a driven shaft (for example, a A pair of opposed inner members 18, 19 provided at respective shaft ends of the gear shaft 13 and an outer side surrounding the pair of inner members 18, 19 and engaged with the inner members 18, 19 respectively in the direction of rotation transmission. It comprises members 20,21 and a center plate 6 fixed to the outer members 20,21 and located between the inner members 18,19.

In this embodiment, the inner members are inner cylinders 18, 19 having crowned straight-tooth external gears 14, 15, and the outer members mesh with the external gears 14, 15 of the inner cylinders 18, 19, respectively. Outer cylinders 20, 21 having internal gears 16, 17 with straight teeth, lubricating oil enclosed in spaces 22 inside the outer cylinders 20, 21 by oil drainers 23 provided at both ends of the outer cylinders 20, 21. (not shown) outflow.

The inner cylinders 18 and 19 are attached to the drive shaft 12 and the driven shaft 13 by taper shrink fitting, respectively, and are further attached to the fastening bolts 27 and 29 formed at the shaft ends of the drive shaft 12 and the driven shaft 13, respectively. It is fixed by screwing fastening nuts 28 and 30 together. As a result, the inner cylinders 18, 19 and the outer cylinders 20, 21 are connected in such a manner that the external gears 14, 15 and the internal gears 16, 17 are engaged with each other so that each axis can be tilted with respect to the inner cylinders 18, 19. It is said that Oil drainers 23 are attached to both ends of the outer cylinders 20 and 21 by fastening bolts 33 . The axially divided outer cylinders 20 and 21 are fastened together by fastening bolts 34 with the center plate 6 interposed therebetween.

The cushioning member 1 is fitted in an annular groove 5 provided around screw holes on the upper surfaces of fastening nuts 28 and 30, for example, hexagonal nuts, for fixing inner cylinders 18 and 19 to the drive shaft 12 and the driven shaft 13, respectively. The elastic portion 2 is fitted and fixed.

Here, when the cushioning member 1 is mounted on the inner member side, a coating of a low-friction material (hereinafter referred to as a low-friction coating 7) should be formed on at least the portion of the center plate 6 that comes into contact with the cushioning member 1. is preferred. In this case, as compared with the case where the cushioning member 1 is used alone, a higher effect of reducing friction of the cushioning member 1 is obtained, and an effect of further reducing wear of the center plate 6 is obtained. Here, the low-friction material forming the low-friction coating 7 on the center plate 6 may be, like the sliding portion 3 of the cushioning member 1, a Teflon sheet attached or a Teflon coating. A coating or the like of a low-friction material such as molybdenum may be used. In the case of this embodiment, the molybdenum disulfide coating is applied for ease of processing, but the present invention is not particularly limited to this. The coating thickness of the low-friction coating 7 is not limited to a specific value because the optimum value differs for each material. In the case of , the thickness is preferably about 10 μm because it is unsuitable for coating a thick film. PFA, ETFE, and modified PTFE are excellent in wear resistance, and FEP and modified PTFE exhibit excellent wear resistance.

In the above-described railroad vehicle gear-shaped flexible shaft coupling, the amount of projection of the buffer member 1, that is, the amount of projection from the upper surface of the fastening nuts 28 and 30 or from the center plate 6, is, for example, 10 to 30 mm, more preferably 10 to 30 mm. It should be about 20 mm. If it is less than 10 mm, the cushioning effect will be insufficient, and if it exceeds 30 mm, there is a risk of impeding the movement of the shaft coupling.

According to the above-described railroad vehicle gear-type flexible shaft coupling, even if radial or axial displacement occurs between the drive shaft 12 and the driven shaft 13 of the flexible shaft coupling, the center plate 6 and the buffer member 1 are not displaced. Contact with the sliding portion 3 mitigates the impact.

A test was conducted on the state of deterioration of the contact surface of the cushioning member with the central plate of the railroad vehicle gear-shaped flexible shaft coupling illustrated in FIG. 2 . In this test, the cushioning member 1 is attached to the upper surfaces of the hexagonal nuts 28 and 30, and molybdenum disulfide (low friction coating 7) is applied to the center of the center plate 6 of the flexible joint. (Examples 1 to 4 and Comparative Examples 1 and 2) were tested.
(Example 1)
A combination of a cushioning member with a Teflon sheet attached to the sliding part of the synthetic rubber elastic part and a center plate not coated with molybdenum disulfide (Example 2)
A combination of a cushioning member with a Teflon sheet attached to the sliding part of the synthetic rubber elastic part and a center plate with a molybdenum disulfide coating (Example 3)
A combination of a cushioning member with a Teflon coating on the sliding part of the synthetic rubber elastic part and a center plate without molybdenum disulfide coating (Example 4)
A combination of a cushioning member with a Teflon coating applied to the sliding portion of the elastic part made of synthetic rubber and a center plate with a molybdenum disulfide coating (Comparative Example 1)
A combination of a cushioning member (conventional product) consisting only of an elastic part made of synthetic rubber and a center plate not coated with molybdenum disulfide (Comparative Example 2)
A combination of a cushioning member (conventional product) consisting only of an elastic part made of synthetic rubber and a central plate with a molybdenum disulfide coating.

(Test results)
Table 1 shows the test results.

From the results of this test, no particular abnormality was found on the contact surface after the test, regardless of whether the center plate was coated with molybdenum disulfide or not (Examples 1 and 2). It was found that the sample was kept in good condition without being broken (see FIG. 4). In addition, in combination with the center plate with the molybdenum disulfide coating (ie, Example 2), compared to the combination with the center plate without the molybdenum disulfide coating (ie, Example 1), the cushioning member, The amount of wear on both center plates was small.

In addition, when the Teflon-coated cushioning member was combined with the molybdenum disulfide-coated center plate (that is, in Example 4), considerable wear occurred on the contact surface after the test was completed. No troublesome abnormalities were observed. On the other hand, in the combination with the center plate without the molybdenum coating (Example 3), although the Teflon coating was worn away from the contact surface after the test and hardly remained, the function as a cushioning member was secured. It had been. That is, it was found that there was no practical problem.

On the other hand, the conventional cushioning members made only of synthetic rubber, regardless of the presence or absence of the molybdenum disulfide coating on the center plate (Comparative Examples 1 and 2), had a large surface wear after the end of the test, and had pockmarks. cracks were generated (see Fig. 5).

For this reason, the surface of the elastic portion 2 of the cushioning member 1 that comes into contact with the mating member where the relative speed difference occurs is coated with a low-friction material having a lower coefficient of friction than the elastic portion 2, that is, the low-friction material is attached. In the case where the sliding portion 3 is coated or coated, the function as the cushioning member 1 is ensured to some extent, and molybdenum disulfide is added to the portion of the center plate 6 that contacts the cushioning member 1. It has become clear that the sliding effect becomes effective by forming a low-friction coating 7 such as a coating.

Although the above embodiment is an example of the preferred embodiment of the present invention, the present invention is not limited to this, and can be modified in various ways without departing from the gist of the present invention. For example, in the above-described embodiment, the cushioning member 1 is fitted on the upper surfaces of fastening nuts (hexagonal nuts) 28, 30 for fixing the inner cylinders 18, 19, which are inner members, to the shafts 12, 13. Although the explanation has been given mainly by giving an example, it is not particularly limited to this, and depending on the case, the center plate 6 may be provided as shown in FIG. In this case, the elastic portion 2 of the cushioning member 1 is fixed to the center of the center plate 6 by, for example, adhesion, while the sliding portion 3 is formed on the surface facing the upper surfaces of the fastening nuts 28 and 30 .

Furthermore, in the above-described embodiment, an example in which the ring-shaped cushioning member 1 is applied to the fastening nuts 28 and 30 and the molybdenum disulfide coating is applied to the center of the center plate 6 has been described. Instead, for example, the cushioning member 1 may be attached to both the fastening nuts 28 and 30 and the center plate 6, or the cushioning member 1 may be attached to only one and the low-friction material coating 8 may be attached to the other. It may be omitted.

In the above-described embodiment, the elastic portion 2 and the sliding portion 3 are made of different materials, but the present invention is not limited to this. The sliding portion 3 may be integrally formed at the same time. For example, if the cushioning member 1 is molded using a synthetic rubber material or a synthetic resin material containing a lubricant such as oil, grease, wax, or a solid lubricant, the difference in the relative velocity of the elastic portion 2 can be minimized. The sliding portion 3 is formed by the lubricant oozing out on the surface in contact with the mating member where the friction occurs. In this case, the elastic portion 2 and the sliding portion 3 can be integrally formed at the same time, which facilitates manufacturing.

Further, in the above-described embodiments, the cushioning member has been mainly described by citing an example in which it is applied to a gear type flexible shaft coupling for railway vehicles, but it is not particularly limited to this, and can be used for flat plate type shaft couplings and other applications. It is also possible to apply it to a gear type flexible shaft coupling, etc.

REFERENCE SIGNS LIST 1 cushioning member 2 elastic portion 3 sliding portion 4 low-friction material 5 concave portion 6 center plate 7 low-friction coating in contact with the sliding portion of the cushioning member

Claims (5)

A pair of opposing inner members provided at respective shaft end portions of the drive shaft and the driven shaft, which face each other on the same axis, surrounds the pair of inner members and engages with the inner members in the direction of rotation transmission. A cushioning member for a railroad vehicle shaft coupling comprising an outer member and a center plate fixed to the outer member and arranged between the inner members,
An elastic part having elasticity attached to the inner member or the center plate, and a sliding part having a surface in contact with a mating member where the relative speed difference of the elastic part is generated is covered with a sheet of low friction material. A cushioning member for a railroad vehicle shaft coupling, comprising: 2. A cushioning member for a railroad car shaft coupling according to claim 1 , wherein said sheet of low friction material is made of polytetrafluoroethylene . 3. A cushioning member for a railroad vehicle shaft coupling according to claim 1, wherein said elastic portion is made of synthetic rubber. A railroad vehicle shaft coupling comprising the cushioning member according to any one of claims 1 to 3 . 5. A shaft coupling for a railway vehicle according to claim 4 , wherein a contact portion of said center plate with said buffer member is coated with a low-friction material.

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