U.S. patent application number 16/961837 was filed with the patent office on 2020-12-10 for elastic bushing device of traction device and railcar bogie.
This patent application is currently assigned to KAWASAKI JUKOGYO KABUSHIKI KAISHA. The applicant listed for this patent is KAWASAKI JUKOGYO KABUSHIKI KAISHA. Invention is credited to Fumikazu KOUNOIKE, Toshifumi MACHIDA, Yosuke MATSUSHITA, Yukihiro SANO, Yoshihiro TAMURA.
Application Number | 20200385032 16/961837 |
Document ID | / |
Family ID | 1000005065918 |
Filed Date | 2020-12-10 |
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United States Patent
Application |
20200385032 |
Kind Code |
A1 |
KOUNOIKE; Fumikazu ; et
al. |
December 10, 2020 |
ELASTIC BUSHING DEVICE OF TRACTION DEVICE AND RAILCAR BOGIE
Abstract
An elastic bushing device of a traction device includes: an
outer tube supported by a bogie; an inner tube into which a center
pin is fitted, the inner tube being arranged at a radially inner
side of the outer tube so as to be spaced apart from the outer tube
and also arranged so as to be located higher in position than the
outer tube; and an elastic body sandwiched between the inner tube
and the outer tube. An outer peripheral surface, opposed to the
elastic body, of the inner tube is inclined downward. An inner
peripheral surface, opposed to the elastic body, of the outer tube
is inclined upward. The elastic body has such a shape that a
surface thereof located close to the inner tube is located higher
in position than a surface thereof located close to the outer
tube.
Inventors: |
KOUNOIKE; Fumikazu;
(Kakogawa-shi, JP) ; MATSUSHITA; Yosuke;
(Kobe-shi, JP) ; TAMURA; Yoshihiro; (Kobe-shi,
JP) ; SANO; Yukihiro; (Kobe-shi, JP) ;
MACHIDA; Toshifumi; (Kobe-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KAWASAKI JUKOGYO KABUSHIKI KAISHA |
Kobe-shi, Hyogo |
|
JP |
|
|
Assignee: |
KAWASAKI JUKOGYO KABUSHIKI
KAISHA
Kobe-shi, Hyogo
JP
|
Family ID: |
1000005065918 |
Appl. No.: |
16/961837 |
Filed: |
December 14, 2018 |
PCT Filed: |
December 14, 2018 |
PCT NO: |
PCT/JP2018/046011 |
371 Date: |
July 13, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B61F 3/04 20130101; B61F
5/16 20130101 |
International
Class: |
B61F 5/16 20060101
B61F005/16 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 12, 2018 |
JP |
2018-003438 |
Claims
1. An elastic bushing device for use in a traction device
connecting a center pin and a bogie in a railcar, the elastic
bushing device comprising: an outer tube supported by the bogie; an
inner tube into which the center pin is fitted, the inner tube
being arranged at a radially inner side of the outer tube so as to
be spaced apart from the outer tube and also arranged so as to be
located higher in position than the outer tube; and an elastic body
sandwiched between the inner tube and the outer tube, wherein: an
outer peripheral surface, opposed to the elastic body, of the inner
tube is inclined downward; an inner peripheral surface, opposed to
the elastic body, of the outer tube is inclined upward; and the
elastic body has such a shape that a surface thereof located close
to the inner tube is located higher in position than a surface
thereof located close to the outer tube.
2. The elastic bushing device according to claim 1, wherein the
inner tube includes an engaging portion which engages with the
center pin such that the inner tube is unrotatable relative to the
center pin.
3. A railcar bogie comprising: the elastic bushing device according
to claim 1; and a bogie frame including a center pin receiver, the
center pin receiver including an inner peripheral surface
supporting the elastic bushing device, wherein: the outer tube of
the elastic bushing device is directly fitted into the center pin
receiver; a projecting portion projecting from the inner peripheral
surface of the center pin receiver toward a center of the center
pin receiver is formed continuously with the inner peripheral
surface of the center pin receiver; a support peripheral surface
which is a part of the inner peripheral surface of the center pin
receiver and located above the projecting portion supports an outer
peripheral surface of the outer tube in a horizontal direction; and
a support bottom surface which is an upper surface of the
projecting portion supports a lower end of the outer tube from
below.
4. A railcar bogie comprising: the elastic bushing device according
to claim 2; and a bogie frame including a center pin receiver, the
center pin receiver including an inner peripheral surface
supporting the elastic bushing device, wherein: the outer tube of
the elastic bushing device is directly fitted into the center pin
receiver; a projecting portion projecting from the inner peripheral
surface of the center pin receiver toward a center of the center
pin receiver is formed continuously with the inner peripheral
surface of the center pin receiver; a support peripheral surface
which is a part of the inner peripheral surface of the center pin
receiver and located above the projecting portion supports an outer
peripheral surface of the outer tube in a horizontal direction; and
a support bottom surface which is an upper surface of the
projecting portion supports a lower end of the outer tube from
below.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to an elastic bushing device
for use in a traction device connecting a center pin and a bogie in
a railcar, and a railcar bogie.
BACKGROUND ART
[0002] A railcar is provided with a traction device configured to
transmit force, such as driving force, acting in a front-rear
direction between a car body and a bogie (see PTL 1, for example).
In the traction device, a center pin provided under a floor of the
car body is fitted into a rubber bushing device internally fitted
to a tubular center pin receiver of a bogie frame. Thus, the car
body and the bogie are coupled to each other.
CITATION LIST
Patent Literature
[0003] PTL 1: Japanese Patent No. 5945137
SUMMARY
Technical Problem
[0004] In the rubber bushing device, a multi-layer rubber body is
interposed between an inner tube and an outer tube. According to
the rubber bushing device configured as above, it is desirable that
when the center pin moves toward one side in a horizontal direction
relative to the center pin receiver, and therefore, the multi-layer
rubber body is compressed at this side, the multi-layer rubber body
is still being compressed at the other side. To be specific, it is
desirable that the multi-layer rubber body is accommodated between
the inner tube and the outer tube in a precompressed state.
However, device cost of the rubber bushing device in which the
multi-layer rubber body is accommodated between the inner tube and
the outer tube in a precompressed state tends to become high due to
reasons in manufacture.
[0005] An object of the present disclosure is to reduce cost of an
elastic bushing device of a traction device of a railcar.
Solution to Problem
[0006] An elastic bushing device of a traction device according to
one aspect of the present disclosure is an elastic bushing device
for use in a traction device connecting a center pin and a bogie in
a railcar. The elastic bushing device includes: an outer tube
supported by the bogie; an inner tube into which the center pin is
fitted, the inner tube being arranged at a radially inner side of
the outer tube so as to be spaced apart from the outer tube and
also arranged so as to be located higher in position than the outer
tube; and an elastic body sandwiched between the inner tube and the
outer tube. An outer peripheral surface, opposed to the elastic
body, of the inner tube is inclined downward. An inner peripheral
surface, opposed to the elastic body, of the outer tube is inclined
upward. The elastic body has such a shape that a surface thereof
located close to the inner tube is located higher in position than
a surface thereof located close to the outer tube.
[0007] According to the above configuration, when railcar assembly
work of fitting the center pin into the inner tube of the elastic
bushing from above is performed, the inner tube moves downward as
the center pin moves downward. As the inner tube moves so as to
become the same in height as the outer tube, the elastic body is
compressed between the outer peripheral surface of the inner tube
and the inner peripheral surface of the outer tube. To be specific,
the elastic body of the elastic bushing can be precompressed only
by performing the assembly work. Therefore, it is unnecessary to
use an expensive elastic bushing which has already been
precompressed before the railcar is assembled, and thus, the cost
can be reduced.
Advantageous Effects
[0008] According to the present disclosure, the cost of the elastic
bushing device of the traction device of the railcar can be
reduced.
BRIEF DESCRIPTION OF DRAWINGS
[0009] FIG. 1 is a side view of a railcar bogie according to an
embodiment when viewed from a car width direction.
[0010] FIG. 2 is a plan view of the bogie of FIG. 1 when viewed
from above.
[0011] FIG. 3 is a perspective view of a center pin of FIG. 1.
[0012] FIG. 4 is a perspective view of an elastic bushing device of
FIG. 2.
[0013] FIG. 5 is a plan view of the elastic bushing device of FIG.
4.
[0014] FIG. 6 is a sectional view showing the elastic bushing
device and its vicinity before a railcar is assembled.
[0015] FIG. 7 is a sectional view showing the elastic bushing
device and its vicinity after the railcar is assembled.
DESCRIPTION OF EMBODIMENTS
[0016] Hereinafter, an embodiment will be described with reference
to the drawings. In the following description, a direction in which
a railcar travels and a car body extends is defined as a car
longitudinal direction, and a lateral direction perpendicular to
the car longitudinal direction is defined as a car width direction.
The car longitudinal direction is also referred to as a front-rear
direction, and the car width direction is also referred to as a
left-right direction.
[0017] FIG. 1 is a side view of a bogie 1 of the railcar according
to the embodiment when viewed from the car width direction. FIG. 2
is a plan view of the bogie 1 of FIG. 1 when viewed from above. As
shown in FIG. 1, the bogie 1 supports a car body 2 of the railcar
from below. The bogie 1 includes a bogie frame 4 supporting the car
body 2 through an air spring (not shown). As shown in FIG. 2, the
bogie frame 4 includes a cross beam 4a and a pair of side sills 4b.
The cross beam 4a extends in the car width direction, and the pair
of side sills 4b are connected to both car width direction end
portions of the cross beam 4a and extend in the car longitudinal
direction. A pair of wheelsets 5 are arranged at both car
longitudinal direction sides of the bogie frame 4 so as to be
located away from each other in the car longitudinal direction.
Each of the wheelsets 5 includes an axle 5a and a pair of wheels
5b. The axle 5a extends in the car width direction, and the pair of
wheels 5b are provided at the axle 5a.
[0018] As shown in FIG. 1, a bearing 6 rotatably supporting the
axle 5a is accommodated in an axle box 7. A spring 8 (coil spring,
for example) serving as a primary suspension is interposed between
the axle box 7 and a side sill 4b. The axle box 7 is elastically
coupled to the bogie frame 4 through a coupling mechanism 9. The
coupling mechanism 9 includes an axle beam 10, a receiving seat 11,
an elastic tube 12, a core rod 13, and a lid 14. The coupling
mechanism 9 constitutes a so-called axle beam type axle box
suspension. The axle beam 10 is formed integrally with the axle box
7 and projects from the axle box 7 toward a bogie middle side in
the car longitudinal direction.
[0019] The receiving seat 11 is provided at the bogie frame 4 so as
to project toward the axle beam 10. The elastic tube 12 is
accommodated in a tubular portion (not shown) which is a tip end
portion of the axle beam 10 and is open toward both sides in the
car width direction. The elastic tube 12 is cylindrical and is
arranged such that an axis thereof extends in the car width
direction. The core rod 13 is accommodated in a radially inner side
of the elastic tube 12. The core rod 13 projects toward both sides
in the car width direction beyond the elastic tube 12. Both end
portions of the core rod 13 are fitted in groove portions 11a of
the receiving seat 11 and are supported by the lid 14 which is
fastened to the receiving seat 11 so as to close the groove
portions 11a.
[0020] As shown in FIG. 2, a traction motor 15 is attached to the
cross beam 4a. A reduction gear 16 is connected to the axle 5a.
Rotational power of the traction motor 15 is transmitted to the
axle 5a through the reduction gear 16, and this drives, i.e.,
rotates the wheels 5b. A center pin receiver 17 including a
cylindrical inner peripheral surface is provided at a middle of the
cross beam 4a. A substantially cylindrical elastic bushing device
18 is inserted into the center pin receiver 17. A center pin 19 is
inserted into the elastic bushing device 18. The center pin 19 is
fixed to an underframe of the car body 2 and projects downward from
an underfloor. To be specific, the center pin receiver 17, the
elastic bushing device 18, and the center pin 19 serve as a
traction device 20 configured to transmit tractive effort of the
bogie 1 to the car body 2.
[0021] FIG. 3 is a perspective view of the center pin 19 of FIG. 1.
As shown in FIG. 3, the center pin 19 includes a shaft portion 21
and a flange portion 22 projecting from an upper end of the shaft
portion 21 in directions perpendicular to an axis of the shaft
portion 21. Bolt holes 21a are formed on a lower end surface of the
shaft portion 21. A key extending in a direction along the axis of
the shaft portion 21 as an engaged portion 21b projects from an
outer peripheral surface of the shaft portion 21. Bolt holes 22a
are formed on the flange portion 22 and are used to fix the center
pin 19 to the underframe of the car body 2. For example, the shaft
portion 21 may be formed by a pipe material, and the flange portion
22 may be formed by bending a steel plate or may be a cast product
or a forged product. The center pin 19 is formed by: separately
manufacturing the shaft portion 21 and the flange portion 22; and
then welding the shaft portion 21 and the flange portion 22 to each
other. Therefore, the shaft portions 21 having different lengths
are only required to be prepared depending on the types of the
railcars. On this account, the flange portion 22 can be used among
different types of the railcars, and the number of parts can be
reduced.
[0022] FIG. 4 is a perspective view of the elastic bushing device
18 of FIG. 2. FIG. 5 is a plan view of the elastic bushing device
18 of FIG. 4. As shown in FIGS. 4 and 5, the elastic bushing device
18 includes an outer tube 31, an inner tube 32, and an elastic body
33. The outer tube 31 is supported by the center pin receiver 17
(see FIG. 2) of the bogie 1. The inner tube 32 is arranged at a
radially inner side of the outer tube 31 so as to be spaced apart
from the outer tube 31, and the center pin 19 (see FIG. 3) is
fitted into the inner tube 32. The elastic body 33 is sandwiched
between the outer tube 31 and the inner tube 32. The inner tube 32
is arranged so as to be located higher in position than the outer
tube 31 (see FIG. 6). The elastic body 33 has such a shape that a
surface thereof located close to the inner tube 32 is located
higher in position than a surface thereof located close to the
outer tube 31. The elastic body 33 has such a shape as to extend
upward as it approaches from the outer tube 31 toward the inner
tube 32.
[0023] Specifically, the elastic body 33 includes a pair of
multi-layer rubber bodies 40. It should be noted that materials
other than rubber may be used as an elastic material. Each of the
multi-layer rubber bodies 40 includes: three circular-arc rubber
layers 41 to 43 laminated concentrically; and two circular-arc
plates 44 and 45 interposed between the circular-arc rubber layers
41 to 43. It should be noted that the number of circular-arc rubber
layers and the number of circular-arc plates are not limited to
these and may be changed in accordance with a space. The three
circular-arc rubber layers 41 to 43 are arranged like stairs so as
to become higher in position in a direction from the outer tube 31
toward the inner tube 32. In a no-load state in which the outer
tube 31 and the inner tube 32 are concentrically arranged, the
circular-arc rubber layers 41 to 43 are not being
precompressed.
[0024] The pair of multi-layer rubber bodies 40 are arranged at
both sides of the inner tube 32 in the car longitudinal direction.
In an area between the outer tube 31 and the inner tube 32, spaces
S are formed at both sides of the inner tube 32 in the car width
direction. With this, the elastic bushing device 18 has a high
elastic coefficient in the car longitudinal direction and a low
elastic coefficient in the car width direction. When displacement
in the car width direction increases, a space surrounded by the
circular-arc plates 44 and 45 and the inner and outer tubes 32 and
31 narrows, and the circular-arc rubber layers 41 to 43 are
compressed. Thus, the elastic coefficient in the car width
direction becomes high. When the displacement in the car
longitudinal direction further increases, the inner tube 32 and the
outer tube 31 contact each other to serve as a stopper. As above,
the elastic bushing device 18 can transmit not only the force
acting in the car longitudinal direction but also the force acting
in the car width direction, and therefore, can also serve as a
lateral displacement stopper of a conventional bogie. The
arrangement configuration of the multi-layer rubber bodies 40 is
not limited to this and may be other configurations (for example, a
configuration in which cylindrical rubber includes lightened parts)
as long as arrangement density of rubber at both sides of the inner
tube 32 in the car width direction is lower than arrangement
density of rubber at both sides of the inner tube 32 in the car
longitudinal direction.
[0025] The inner tube 32 includes an engaging portion 32a which
engages with the center pin 19 such that the inner tube 32 is
unrotatable relative to the center pin 19. Specifically, a keyway
extending in the upper-lower direction is formed on an inner
peripheral surface of the inner tube 32 as the engaging portion
32a. The key that is the engaged portion 21b of the shaft portion
21 of the center pin 19 is engaged with the engaging portion 32a.
Since the center pin 19 does not rotate relative to the inner tube
32 as above, there is no slide portion, and the ease of maintenance
is excellent. In the present embodiment, one keyway is provided.
However, a plurality of keyways may be provided. Moreover, the
present embodiment is not limited to the keyway, and a mechanism,
such as a spline, configured to prevent relative rotation may be
used.
[0026] FIG. 6 is a sectional view showing the elastic bushing
device 18 and its vicinity before the railcar is assembled. As
shown in FIG. 6, the center pin receiver 17 includes a projecting
portion 17a projecting from an inner peripheral surface of the
center pin receiver 17 toward a center of the center pin receiver
17. The projecting portion 17a is formed continuously with the
inner peripheral surface of the center pin receiver 17 by
subjecting the inner peripheral surface of the center pin receiver
17 to machine work. The elastic bushing device 18 is fitted into
the center pin receiver 17 from above. A support peripheral surface
17b which is part of the inner peripheral surface of the center pin
receiver 17 and located above the projecting portion 17a supports
an outer peripheral surface of the outer tube 31 in a horizontal
direction.
[0027] A support bottom surface 17c that is an upper surface of the
projecting portion 17a of the center pin receiver 17 supports a
lower end of the outer tube 31 from below. The outer tube 31 of the
elastic bushing device 18 is directly fitted into the center pin
receiver 17 and contacts the inner peripheral surface of the center
pin receiver 17. As above, since the outer tube 31 of the elastic
bushing device 18 is directly fitted into the center pin receiver
17, it is unnecessary to provide a structure in which a support
sleeve supporting the outer tube 31 is welded and fixed to the
inner peripheral surface of the center pin receiver 17. Therefore,
manufacturing steps of the bogie can be reduced.
[0028] An inner peripheral surface 31a, opposed to the multi-layer
rubber body 40, of the outer tube 31 is inclined upward. An outer
peripheral surface 32a, opposed to the multi-layer rubber body 40,
of the inner tube 32 is inclined downward. To be specific, the
inner peripheral surface 31a and the outer peripheral surface 32a
which are opposed to each other are formed in a conical shape which
increases in diameter toward an upper side. The inner peripheral
surface 31a and the outer peripheral surface 32a are substantially
parallel to each other in a vertical sectional view. The
circular-arc rubber layers 41 to 43 arranged like stairs are
sandwiched between the inclined inner peripheral surface 31a and
the inclined outer peripheral surface 32a in a direction that is
oblique relative to the horizontal direction.
[0029] FIG. 7 is a sectional view showing the elastic bushing
device 18 and its vicinity after the railcar is assembled. As shown
in FIG. 7, when assembling the railcar, the shaft portion 21 of the
center pin 19 is fitted into an inner space of the inner tube 32 of
the elastic bushing device 18 from above. Then, an upper end
surface of the inner tube 32 of the elastic bushing device 18 is
pushed downward by the center pin 19 to move downward. With this,
the circular-arc rubber layers 41 to 43 are compressed by the inner
peripheral surface 31a of the outer tube 31 and the outer
peripheral surface 32a of the inner tube 32, and the inner tube 32
becomes substantially the same in height as the outer tube 31.
After the railcar is assembled, the circular-arc rubber layers 41
to 43 are being precompressed between the outer tube 31 and the
inner tube 32.
[0030] Finally, a height stopper plate 46 is fixed by bolts B to
the lower end surface of the shaft portion 21 of the center pin 19
which projects downward beyond the center pin receiver 17. A
diameter of the height stopper plate 46 is larger than a minimum
inner diameter (inner diameter of the projecting portion 17a) of
the center pin receiver 17. In the present embodiment, the height
stopper plate 46 has a circular shape. However, the shape of the
height stopper plate 46 is not limited to this. The height stopper
plate 45 may have a different shape, such as a rectangular shape,
as long as the height stopper plate 45 projects in a radial
direction at somewhere on a circumference of a hole of the center
pin receiver 17.
[0031] According to the above-described configuration, when railcar
assembly work of fitting the center pin 19 into the inner tube 32
of the elastic bushing device 18 from above is performed, the inner
tube 32 moves downward as the center pin 19 moves downward. As the
inner tube 32 moves so as to become the same in height as the outer
tube 31, the elastic body 33 is compressed between the outer
peripheral surface 32a of the inner tube 32 and the inner
peripheral surface 31a of the outer tube 31. To be specific, the
elastic body 33 of the elastic bushing device 18 can be
precompressed only by performing the assembly work. Therefore, it
is unnecessary to use an expensive elastic bushing which has
already been precompressed before the railcar is assembled, and
thus, the cost can be reduced. Moreover, since the elastic bushing
device 18 can transmit the force in the car longitudinal direction
and the force in the car width direction and serves as a traction
link and lateral displacement stopper of a conventional bogie,
these members of the conventional bogie can be omitted, and thus,
the cost can be reduced.
[0032] Moreover, the inner tube 32 of the elastic bushing device 18
engages with the center pin 19 so as to be unrotatable relative to
the center pin 19. Therefore, when, for example, the railcar turns,
the center pin 19 rotates integrally with the inner tube 32, and
relative rotation between the inner tube 32 and the outer tube 31
is absorbed by elasticity of the elastic body 33 in a shearing
direction. On this account, it is unnecessary to interpose, for
example, a sliding part between the center pin 19 and the inner
tube 32. Thus, the configuration of the traction device 20 can be
simplified, and the cost can be reduced.
[0033] The above embodiment has described a bolsterless bogie.
However, the traction device 20 may be applied to a
bolster-equipped bogie instead of the bolsterless bogie. In this
case, the center pin may project downward from the bolster.
REFERENCE SIGNS LIST
[0034] 1 bogie [0035] 4 bogie frame [0036] 17 center pin receiver
[0037] 17b support peripheral surface [0038] 17c support bottom
surface [0039] 18 elastic bushing device [0040] 19 center pin
[0041] 20 traction device [0042] 31 outer tube [0043] 31a inner
peripheral surface [0044] 32 inner tube [0045] 32a outer peripheral
surface [0046] 33 elastic body
* * * * *