DESCRIPTION
FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
GEAR DEVICE, BEARING REMOVAL DEVICE, AND BEARING REMOVAL
METHOD;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND
EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100-8310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
2
DESCRIPTION
Title of Invention
GEAR DEVICE, BEARING REMOVAL DEVICE, AND BEARING REMOVAL
METHOD
5
Technical Field
[0001] The present disclosure relates to a gear device, a bearing remover, and a
bearing removal method.
Background Art
10 [0002] A railway vehicle includes a gear device that transmits rotational force from
a motor to an axle. An example of such a gear device is described in Patent Literature 1.
The gear device described in Patent Literature 1 includes a pinion coupled to the output
shaft of the motor and a gear wheel engaged with the pinion and coupled to the axle.
The gear device further includes output shaft bearings that support the output shaft in a
15 rotatable manner, axle bearings that support the axle in a rotatable manner, and a gear box
that accommodates the pinion, the gear wheel, the output shaft bearings, and the axle
bearings.
Citation List
Patent Literature
20 [0003] Patent Literature 1: Unexamined Japanese Patent Application Publication
No. 2019-219051
Summary of Invention
Technical Problem
[0004] The output shaft bearings receive the load resulting from the weight of a
25 rotator supported by the output shaft bearings in a rotatable manner, or more specifically,
the weight of the output shaft to which the pinion is attached. The output shaft bearings
thus have a shorter life than the pinion. Similarly, the axle bearings receive a load
3
resulting from the weight of a rotator supported by the axle bearings in a rotatable
manner, or more specifically, the weight of the axle to which the gear wheel is attached.
The axle bearings thus have a shorter life than the gear wheel. Thus, among the
components in the gear device, the output shaft bearings and the axle bearings may be
5 replaced. For example, in the gear device described in Patent Literature 1, pinion
bearings can be removed easily by removing a lid, to which the output shaft bearings are
fitted, together with the output shaft bearings from the gear device, but removal of the
axle bearings is complicated.
[0005] More specifically, to remove the axle bearings that support the axle, a
10 bearing box holding the axle bearings is removed from the gear box. To remove the
axle bearings, the axle is then to be removed first from the gear device. When the gear
wheel is tightly fitted to the axle, removal of the axle from the gear device is complicated,
and thus removal of the axle bearings from the gear device is complicated. In addition
to a gear device installed in a railway vehicle, such inconvenience may occur in various
15 gear devices including bearings that support a shaft to which a gear is attached in a
rotatable manner.
[0006] An objective of the present disclosure is to provide a gear device, a bearing
remover, and a bearing removal method allowing easy removal of a bearing.
Solution to Problem
20 [0007] To achieve the above objective, a gear device according to an aspect of the
present disclosure includes a gear, a pair of bearings, and a plurality of removable
members. The gear is attached to a shaft to rotate integrally with the shaft. The pair of
bearings are located across the gear in a direction in which the shaft extends. The pair
of bearings support the shaft in a rotatable manner. The plurality of removable
25 members are attached to two surfaces of the gear intersecting with the shaft. Each
removable member of the plurality of removable members faces a bearing of the pair of
bearings located across the gear.
4
Advantageous Effects of Invention
[0008] The gear device according to the above aspect of the present disclosure
includes the plurality of removable members attached to the gear. Each removable
member of the removable members faces either bearing of the pair of bearings located
5 across the gear. Thus, moving the removable members in contact with the bearings
along the shaft allows easy removal of the bearings from the shaft.
Brief Description of Drawings
[0009] FIG. 1 is a top view of a truck to which gear devices according to an
embodiment are attached;
10 FIG. 2 is a cross-sectional view of the gear device according to the embodiment
taken along line II-II as viewed in the direction indicated by the arrows in FIG. 1;
FIG. 3 is a side view of the gear device according to the embodiment taken along
line III-III as viewed in the direction indicated by the arrows in FIG. 2;
FIG. 4 is a partial cross-sectional view of the gear device according to the
15 embodiment;
FIG. 5 is a cross-sectional view of the gear device according to the embodiment;
FIG. 6 is a diagram describing a method for removing bearings in the gear device
according to the embodiment;
FIG. 7 is a diagram describing a method for removing bearings in the gear device
20 according to the embodiment;
FIG. 8 is a cross-sectional view of a gear device according to a modification of the
embodiment; and
FIG. 9 is a diagram describing a method for removing bearings in the gear device
according to the modification of the embodiment.
25 Description of Embodiments
[0010] A gear device, a bearing remover, and a bearing removal method according
to an embodiment of the present disclosure are described in detail below with reference to
5
the drawings. In the figures, the same reference signs denote the same or equivalent
components.
[0011] Gear devices 1 according to Embodiment 1 are described using gear devices
installed on a railway vehicle as examples. As illustrated in FIG. 1, the gear devices 1
5 are attached to a truck 50 in a railway vehicle. Motors 51 that transmit rotational force
to the gear devices 1 through couplings 52 are attached to the truck 50. Axles 53 are
attached to the truck 50 with axle springs, which are not illustrated, in between. Wheels
54 are attached to two ends of each axle 53.
[0012] In FIG. 1, Z-axis indicates the vertical direction, X-axis indicates the travel
10 direction of the railway vehicle, and Y-axis indicates the width direction of the railway
vehicle, or the direction in which each axle 53 extends. X-axis, Y-axis, and Z-axis are
perpendicular to one another. The same applies to the other drawings.
[0013] Each motor 51 is a power source driven by power fed from a power source,
which is not illustrated, to generate rotational force. When each motor 51 is driven, a
15 shaft 51a rotates.
Each coupling 52 transmits rotational force transmitted from the corresponding
shaft 51a to the gear device 1 through a drive shaft 52a. In other words, each drive shaft
52a is driven to rotate by the corresponding motor 51 serving as a power source.
Each axle 53 rotates integrally with the corresponding wheels 54 when receiving
20 rotational force from the corresponding gear device 1.
[0014] Each gear device 1 includes at least one gear and a pair of bearings that
support, in a rotatable manner, a shaft to which the gear is attached. As illustrated in
FIG. 2 that is a cross-sectional view taken along line II-II as viewed in the direction
indicated by the arrows in FIG. 1, and FIG. 3 that is a cross-sectional view taken along
25 line III-III as viewed in the direction indicated by the arrows in FIG. 2, each gear device 1
includes two gears 11 and 12, a pair of bearings that support, in a rotatable manner, a
shaft to which the gear 11 is attached, and a pair of bearings that support, in a rotatable
6
manner, a shaft to which the gear 12 is attached. In the example described below, the
gear 11 attached to the drive shaft 52a is referred to as a drive gear 11, and the gear 12
meshing with the drive gear 11 and attached to the axle 53 serving as a follower shaft is
referred to as a follower gear 12 for distinguishment. A pair of bearings that support the
5 axle 53 in a rotatable manner are referred to as follower-shaft bearings 17a and 17b, and a
pair of bearings that support the drive shaft 52a are referred to as drive-shaft bearings.
The drive-shaft bearings are not illustrated.
[0015] The gear device 1 further includes a pair of rings 13a and 13b as multiple
removable members. The rings 13a and 13b are attached to the follower gear 12 with
10 fasteners 14a and 14b. The removable members are used to remove the follower-shaft
bearings 17a and 17b from the corresponding axle 53. The removable members are
firmly attached to the follower gear 12 not to be separate from the follower gear 12
during the rotation of the follower gear 12, and are removable from the follower gear 12
with, for example, a tool without being broken.
15 [0016] Each gear device 1 further includes the pair of follower-shaft bearings 17a
and 17b that support the axle 53 in a rotatable manner and bearing holders 18a and 18b
that respectively hold the follower-shaft bearings 17a and 17b. The follower-shaft
bearing 17a is a rolling bearing including an inner race 21a, an outer race 22a, and rolling
elements 23a. The follower-shaft bearing 17b is a rolling bearing including an inner
20 race 21b, an outer race 22b, and rolling elements 23b. The gear device 1 further
includes a gear box 15 and a lid 16. The gear box 15 accommodates the drive gear 11,
the follower gear 12, the pair of follower-shaft bearings 17a and 17b, and the pair of rings
13a and 13b. The lid 16 closes an opening in the gear box 15 at the top in the vertical
direction. The gear device 1 further includes oil throwers 19a and 19b and an earth ring
25 20. The oil throwers 19a and 19b suppress leakage of oil from the gear box 15. The
earth ring 20 passes a current from the body of the railway vehicle to the rails through a
ground brush, which is not illustrated.
7
[0017] In the gear device 1 with the above structure, when the ring 13a is removed
from the follower gear 12 and then the ring 13a in contact with the follower-shaft bearing
17a is moved along the axle 53, the follower-shaft bearing 17a can be removed easily.
Similarly, when the ring 13b in contact with the follower-shaft bearing 17b is moved
5 along the axle 53, the follower-shaft bearing 17b can be removed easily. The
components of the gear device 1 are described in detail below.
[0018] As illustrated in FIGS. 1 and 2, the drive gear 11 is attached to the drive
shaft 52a and rotates integrally with the drive shaft 52a. More specifically, as the shaft
51a of the motor 51 rotates, the drive gear 11 rotates integrally with the drive shaft 52a.
10 The drive gear 11 meshes with the follower gear 12 and transmits rotational force
transmitted from the shaft 51a of the motor 51 through the coupling 52 to the follower
gear 12.
[0019] As illustrated in FIG. 2, the follower gear 12 meshing with the drive gear 11
is attached to the axle 53. More specifically, the follower gear 12 is tightly fitted to the
15 axle 53. The follower gear 12 rotates integrally with the axle 53 as the drive gear 11
rotates. In Embodiment 1, the follower gear 12 has a larger diameter and more teeth
than the drive gear 11.
[0020] As illustrated in FIG. 4 that is a partially enlarged view of FIG. 3, the
follower gear 12 has screw holes 12a for attaching the ring 13a in the surface facing in the
20 positive Y-direction. The fasteners 14a and 14b are not illustrated in FIG. 4. The
screw holes 12a are threaded to allow the fasteners 14a in FIG. 3 to be screwed in. In
Embodiment 1, four screw holes 12a are arranged at regular intervals in the
circumferential direction about Y-axis. As illustrated in FIG. 2, the ring 13a is attached
to the follower gear 12 at four points.
25 [0021] The follower gear 12 has screw holes 12b for attaching the ring 13b in the
surface facing in the negative Y-direction. The screw holes 12b are threaded to allow
the fasteners 14b to be screwed in. In Embodiment 1, similarly to the screw holes 12a,
8
four screw holes 12b are arranged at regular intervals in the circumferential direction
about Y-axis. The ring 13b is attached to the follower gear 12 at four points.
[0022] The ring 13a is attached to the follower gear 12 and faces the follower-shaft
bearing 17a. In Embodiment 1, the ring 13a has an outer diameter larger than the inner
5 diameter of the outer race 22a in the follower-shaft bearing 17a at the surface of the outer
race 22a facing the ring 13a. The ring 13a has an outer diameter that is preferably larger
than the outer diameter of the outer race 22a in the follower-shaft bearing 17a at the
surface of the outer race 22a facing the ring 13a. The ring 13a has an inner diameter
smaller than the outer diameter of the inner race 21a in the follower-shaft bearing 17a at
10 the surface of the inner race 21a facing the ring 13a. The ring 13a has an inner
circumferential surface that is preferably spaced from the outer circumferential surface of
the axle 53.
[0023] As illustrated in FIG. 4, the ring 13a has through-holes 24a for receiving the
fasteners 14a. More specifically, the through-holes 24a are located to correspond to the
15 screw holes 12a. When the fasteners 14a placed through the through-holes 24a are
screwed into the screw holes 12a, the ring 13a is attached to the follower gear 12.
[0024] The ring 13b is attached to the follower gear 12 and faces the follower-shaft
bearing 17b. In Embodiment 1, the ring 13b has an outer diameter larger than the inner
diameter of the outer race 22b in the follower-shaft bearing 17b at the surface of the outer
20 race 22b facing the ring 13b. The ring 13b has an outer diameter that is preferably
larger than the outer diameter of the outer race 22b in the follower-shaft bearing 17b at
the surface of the outer race 22b facing the ring 13b. The ring 13b has an inner diameter
smaller than the outer diameter of the inner race 21b in the follower-shaft bearing 17b at
the surface of the inner race 21b facing the ring 13b. The ring 13b has an inner
25 circumferential surface that is preferably spaced from the outer circumferential surface of
the axle 53.
[0025] The ring 13b has through-holes 24b for receiving the fasteners 14b. More
9
specifically, the through-holes 24b are located to face the screw holes 12b. When the
fasteners 14b extending through the through-holes 24b are attached to the follower gear
12, the ring 13b is attached to the follower gear 12.
[0026] The rings 13a and 13b are attached to the follower gear 12 and rotate
5 integrally with the follower gear 12. Thus, the rings 13a and 13b are formed from a
material having rigidity to the extent that the rings 13a and 13b are not broken by the
rotation. For example, the rings 13a and 13b are annular members formed from a steel
material, such as chrome molybdenum steel, with a thickness of 10 mm.
[0027] The fasteners 14a illustrated in FIG. 3 are threaded to be screwable into the
10 screw holes 12a in the follower gear 12 through the through-holes 24a in the ring 13a.
The fasteners 14b are threaded to be screwable into the screw holes 12b in the
follower gear 12 through the through-holes 24b in the ring 13b.
[0028] The gear box 15 illustrated in FIGS. 2 and 3 accommodates the drive gear
11, the follower gear 12, the rings 13a and 13b attached to the follower gear 12, the
15 follower-shaft bearings 17a and 17b, and a pair of drive-shaft bearings, which is not
illustrated, that supports the drive shaft 52a in a rotatable manner. As illustrated in FIG.
5 that corresponds to FIG. 3 without illustrating the bearing holders 18a and 18b, the gear
box 15 has openings 15a and 15b in two surfaces intersecting with Y-axis. More
specifically, the gear box 15 has the openings 15a and 15b in portions facing the rings
20 13a and 13b. To place the axle 53 through the follower gear 12 accommodated in the
gear box 15, the openings 15a and 15b are shaped and sized to receive the axle 53. The
opening 15a is shaped and sized to receive the follower-shaft bearing 17a and the ring
13a. The opening 15b is shaped and sized to receive the follower-shaft bearing 17b and
the ring 13b.
25 [0029] As illustrated in FIG. 3, the opening 15a is closed with the bearing holder
18a and the oil thrower 19a, and the opening 15b is closed with the bearing holder 18b
and the oil thrower 19b. The opening in the gear box 15 at the top in the vertical
10
direction is closed with the lid 16. The gear box 15 has no opening at the bottom in the
vertical direction. The drive gear 11 and the follower gear 12 are placed in and out of
the gear box 15 through the opening at the top in the vertical direction.
[0030] The follower-shaft bearings 17a and 17b support the axle 53 in a rotatable
5 manner. More specifically, the inner race 21a in the follower-shaft bearing 17a is
attached to the axle 53 and rotates integrally with the axle 53. More specifically, the
inner race 21a is fixed to the axle 53 immovably in Y-direction during the rotation of the
axle 53. For example, the inner race 21a is press-fitted to the axle 53. The outer race
22a is held on the bearing holder 18a. More specifically, the outer race 22a is fixed to
10 the bearing holder 18a. For example, the outer race 22a is press-fitted to the bearing
holder 18a. The rolling elements 23a are located between the inner race 21a and the
outer race 22a to roll as the inner race 21a rotates integrally with the axle 53. When the
bearing holder 18a is removed from the gear box 15, the follower-shaft bearing 17a is
slidable in Y-direction. More specifically, when pushed in the positive Y-direction by
15 the ring 13a, the follower-shaft bearing 17a moves in the positive Y-direction, and is thus
removable from the axle 53 without being broken.
[0031] The inner race 21b in the follower-shaft bearing 17b is attached to the axle
53 and rotates integrally with the axle 53. More specifically, the inner race 21b is firmly
fixed to the axle 53 immovably in Y-direction during the rotation of the axle 53. For
20 example, the inner race 21b is press-fitted to the axle 53. The outer race 22b is held on
the bearing holder 18b. More specifically, the outer race 22b is fixed to the bearing
holder 18b. For example, the outer race 22b is press-fitted to the bearing holder 18b.
The rolling elements 23b are located between the inner race 21b and the outer race 22b to
roll as the inner race 21b rotates integrally with the axle 53. When the bearing holder
25 18b is removed from the gear box 15, the follower-shaft bearing 17b is slidable in Ydirection. More specifically, when pressed by the ring 13b in the negative Y-direction,
the follower-shaft bearing 17b moves in the negative Y-direction, and is removable from
11
the axle 53 without being broken.
[0032] The bearing holder 18a illustrated in FIG. 3 is attached to the surface of the
gear box 15 facing in the positive Y-direction. The bearing holder 18 holds the
follower-shaft bearing 17a and closes the opening 15a in the gear box 15 illustrated in
5 FIG. 5. The bearing holder 18b illustrated in FIG. 3 is attached to the surface of the gear
box 15 facing in the negative Y-direction. The bearing holder 18b holds the followershaft bearing 17b and closes the opening 15b in the gear box 15 illustrated in FIG. 5.
[0033] The oil throwers 19a and 19b are attached to the axle 53 at positions to hold
the follower-shaft bearings 17a and 17b in between. More specifically, the oil throwers
10 19a and 19b are fixed to the axle 53. For example, the oil throwers 19a and 19b are
press-fitted to the axle 53. The oil throwers 19a and 19b have recesses and protrusions
on the outer circumferential surfaces. The recesses and protrusions on the outer
circumferential surface of the oil thrower 19a define a labyrinth flow path between the oil
thrower 19a and the bearing holder 18a. The recesses and protrusions on the outer
15 circumferential surface of the oil thrower 19b define a labyrinth flow path between the oil
thrower 19b and the bearing holder 18b. These labyrinth flow paths prevent leakage of
a lubricant, which is not illustrated, contained in the gear box 15 from the gear box 15.
[0034] The earth ring 20 is formed from a conductive material, and passes a current
from the body of the railway vehicle through a ground brush, which is not illustrated, to
20 the rails. The earth ring 20 is firmly fixed to the axle 53 immovably in Y-direction
during the rotation of the axle 53. For example, the earth ring 20 is press-fitted to the
axle 53.
[0035] A method for removing the follower-shaft bearings 17a and 17b from the
gear device 1 with the above structure is described below. The gear devices 1 are
25 removed from the truck 50 illustrated in FIG. 1, the wheels 54 are removed from the
axles 53, and, as illustrated in FIG. 5, the bearing holders 18a and 18b are removed from
the gear device 1 illustrated in FIG. 3. Thereafter, the follower-shaft bearings 17a and
12
17b are removed using bearing removers 30 illustrated in FIG. 6.
[0036] More specifically, each bearing remover 30 includes removal tools 31
attachable to the ring 13a or 13b, a driver 32 that urges the ring 13a or 13b away from the
follower gear 12 by extending a rod 32a, a plate 33 in contact with the rod 32a, and
5 fasteners 34 that fix the removal tools 31 to the plate 33.
[0037] In Embodiment 1, each bearing remover 30 includes four rod-like removal
tools 31. Each removal tool 31 has two threaded ends. The through-holes 24a in the
ring 13a and the through-holes 24b in the ring 13b are threaded portions, or more
specifically, threaded holes into which one threaded end of the removal tool 31 is
10 screwable. In other words, the through-holes 24a in the ring 13a and the through-holes
24b in the ring 13b are examples of device receivers to which the bearing remover 30 is
attachable.
[0038] The other end of each removal tool 31 extends through the corresponding
plate 33 and is fixed to the plate 33 by being fastened with the corresponding fastener 34.
15 Each removal tool 31 is formed from a material, such as iron or a steel material, that has
rigidity to the extent that each removal tool 31 is not deformed with a force applied when
the rings 13a and 13b are removed.
[0039] The driver 32 is a hydraulic cylinder having, for example, one end in contact
with the axle 53 and the other end receiving the rod 32a. The driver 32 extends the rod
20 32a away from the axle 53.
The plate 33 is placed in contact with the rod 32a when the rod 32a is at an initial
position, or the rod 32a is not extended. For example, the plate 33 is attached to the rod
32a when the rod 32a at the initial position is fitted to a fit-in hole in the plate 33. As
described above, with the plate 33 attached to the rod 32a, the removal tools 31 are fixed
25 to the plate 33. The plate 33 is formed from a material, such as iron or a steel material,
that has rigidity to the extent that the plate 33 is not deformed when being pressed by the
rod 32a.
13
[0040] A method for removing the follower-shaft bearing 17a from the gear device
1 is described below. As illustrated in FIG. 6, the four removal tools 31 in the bearing
remover 30 located in the positive Y-direction from the gear device 1 each have one end
inserted and screwed into the corresponding through-hole 24a in the ring 13a. Thus, the
5 four removal tools 31 are attached to the ring 13a. The removal tools 31 are not inserted
into the screw holes 12a in the follower gear 12. To prevent the removal tools 31 from
being inserted into the screw holes 12a, the through-holes 24a in the ring 13a are
preferably larger than the screw holes 12a in the follower gear 12. In this case, the
fasteners 14a may be shaped to have radially stepwise sizes.
10 [0041] The other end of each of the four removal tools 31 extends through the plate
33 and is fastened with the corresponding fastener 34. Thus, the four removal tools 31
are attached to the plate 33.
[0042] The driver 32 extends the rod 32a away from the axle 53, or in the positive
Y-direction. Thus, the plate 33 moves in the positive Y-direction, and the four removal
15 tools 31 move in the positive Y-direction with the plate 33 moving. Thus, the ring 13a
to which the four removal tools 31 are attached is urged away from the follower gear 12,
or in the positive Y-direction, and moves in the positive Y-direction. In other words, the
driver 32 operates as a driver that urges the ring 13a away from the follower gear 12.
[0043] As described above, the ring 13a has an outer diameter larger than the inner
20 diameter of the outer race 22a in the follower-shaft bearing 17a at the surface of the outer
race 22a facing the ring 13a, and the ring 13a has an inner diameter smaller than the outer
diameter of the inner race 21a in the follower-shaft bearing 17a at the surface of the inner
race 21a facing the ring 13a. Thus, when the ring 13a moves in the positive Y-direction,
the ring 13a comes in contact with the follower-shaft bearing 17a. When the ring 13a is
25 further urged by the driver 32 away from the follower gear 12, as illustrated in FIG. 7, the
ring 13a in contact with the follower-shaft bearing 17a moves in the positive Y-direction
along the axle 53. As described above, when the ring 13a moves in the positive Y-
14
direction, the follower-shaft bearing 17a and the oil thrower 19a move in the positive Ydirection. When the plate 33 is removed after the oil thrower 19a arrives at the end of
the axle 53, the follower-shaft bearing 17a and the oil thrower 19a can be removed from
the axle 53.
5 [0044] The follower-shaft bearing 17b is removed in the same manner as well.
More specifically, as illustrated in FIG. 6, the four removal tools 31 in the bearing
remover 30 located in the negative Y-direction from the gear device 1 each have one end
inserted and screwed into the corresponding through-hole 24b in the ring 13b. Thus, the
four removal tools 31 are attached to the ring 13b. The removal tools 31 are not inserted
10 into the screw holes 12b in the follower gear 12. To prevent the removal tools 31 from
being inserted into the screw holes 12b, the through-holes 24b in the ring 13b are
preferably larger than the screw holes 12b in the follower gear 12. In this case, the
fasteners 14b may be shaped to have radially stepwise sizes.
[0045] The other end of each of the four removal tools 31 extends through the plate
15 33 and is fastened with the corresponding fastener 34. Thus, the four removal tools 31
are attached to the plate 33.
[0046] The driver 32 extends the rod 32a away from the axle 53, or in the negative
Y-direction. Thus, the plate 33 moves in the negative Y-direction, and the four removal
tools 31 move in the negative Y-direction with the plate 33 moving. Thus, the ring 13b
20 to which the four removal tools 31 are attached is urged away from the follower gear 12,
or in the negative Y-direction, and moves in the negative Y-direction. In other words,
the driver 32 operates as a driver that urges the ring 13b away from the follower gear 12.
[0047] As described above, the ring 13b has an outer diameter larger than the inner
diameter of the outer race 22b in the follower-shaft bearing 17b at the surface of the outer
25 race 22b facing the ring 13b, and the ring 13b has an inner diameter smaller than the outer
diameter of the inner race 21b in the follower-shaft bearing 17b at the surface of the inner
race 21b facing the ring 13b. Thus, when the ring 13b moves in the negative Y-
15
direction, the ring 13b comes in contact with the follower-shaft bearing 17b. When the
ring 13b is further urged by the driver 32 away from the follower gear 12, as illustrated in
FIG. 7, the ring 13b in contact with the follower-shaft bearing 17b moves in the negative
Y-direction along the axle 53. As described above, when the ring 13b moves in the
5 negative Y-direction, the follower-shaft bearing 17b, the oil thrower 19b, and the earth
ring 20 move in the negative Y-direction. When the plate 33 is removed after the earth
ring 20 arrives at the end of the axle 53, the follower-shaft bearing 17b, the oil thrower
19b, and the earth ring 20 can be removed from the axle 53.
[0048] After the follower-shaft bearings 17a and 17b are removed, the rings 13a
10 and 13b are attached to the follower gear 12 again, and new follower-shaft bearings 17a
and 17b are attached to the axle 53. Thereafter, the oil throwers 19a and 19b, the earth
ring 20, and the bearing holders 18a and 18b are attached. This completes the
replacement of the follower-shaft bearings 17a and 17b.
[0049] As described above, in the gear device 1 including the rings 13a and 13b, the
15 follower-shaft bearings 17a and 17b can be removed easily from the axle 53 using the
bearing remover 30. As described above, the rings 13a and 13b in contact with the
follower-shaft bearings 17a and 17b move along the axle 53, and thus the follower-shaft
bearings 17a and 17b are removed from the axle 53. To remove the follower-shaft
bearings 17a and 17b in the above manner, the follower gear 12 remains unremoved from
20 the axle 53. Thus, the follower-shaft bearings 17a and 17b can be removed easily from
the gear device 1.
[0050] The present disclosure is not limited to the above embodiment.
The rings 13a and 13b may be attached to the follower gear 12 in any manner,
rather than being fastened with the fasteners 14a and 14b, when the rings 13a and 13b are
25 firmly attached without being removed from the follower gear 12 during rotation. In
one example, the rings 13a and 13b may be attached to the follower gear 12 by shrink
fitting.
16
[0051] In examples other than the above example, the removal tools 31 may be
attached to the rings 13a and 13b in any manner without being separated from the rings
13a and 13b with a force applied when the rings 13a and 13b are removed. In one
example, the rings 13a and 13b may each have a threaded protrusion, and the removal
5 tools 31 may each have a threaded screw hole at one end. The protrusion on the ring
13a or 13b may be screwed into the screw hole at one end of the corresponding removal
tool 31 to attach the removal tool 31 to the ring 13a or 13b.
[0052] In another example, the rings 13a and 13b may have fit portions to which
the bearing remover 30 can be fit, to serve as device receivers to which the bearing
10 remover 30 is attachable. More specifically, the through-holes 24a in the ring 13a and
the through-holes 24b in the ring 13b may be fit-in holes into which the removal tools 31
can be fitted. For example, an elastic member that deforms when pressed may be
attached to one end of the removal tool 31. One of the removal tools 31 to which the
elastic member is attached may be inserted into and fitted to the through-hole 24a or 24b.
15 [0053] In another example, a gear device 2 illustrated in FIG. 8 includes hook-like
locks 26a and 26b serving as device receivers to which the bearing remover 30 is
attachable. The locks 26a and 26b have distal ends preferably protruding in the same
direction. As illustrated in FIG. 9, the bearing remover 30 may include removal tools 35
each having one end bent to be hooked on the corresponding lock 26a or 26b.
20 [0054] The rings 13a, 13b, 25a, and 25b may not be annular but may have any other
shapes. For example, the rings 13a, 13b, 25a, and 25b may have a partially-open
annular shape, or a shape including multiple arcs spaced from one another. In another
example, the rings 13a, 13b, 25a, and 25b may have a polygonal shape with a throughhole at the center, or a shape including multiple rectangles spaced from one another. In
25 another example, the rings 13a, 13b, 25a, and 25b may not be a plate but may be a block.
[0055] The rings 13a, 13b, 25a, and 25b may be attached to the drive gear 11. For
example, when the rings 13a and 13b are attached to the drive gear 11, a pair of drive-
17
shaft bearings, which is not illustrated, that supports the drive shaft in a rotatable manner
can be removed easily. The rings 13a and 13b may be attached to the drive gear 11 and
the follower gear 12.
[0056] The follower-shaft bearings 17a and 17b may be sliding bearings, in place of
5 the rolling bearings described in the above embodiment.
[0057] The oil throwers 19a and 19b may be attached to the axle 53 in a manner
other than in the above example. The oil throwers 19a and 19b may be firmly attached
to the axle 53 immovably in Y-direction during the rotation of the axle 53. For
example, the oil throwers 19a and 19b may move in the circumferential direction without
10 moving in Y-direction during the rotation of the axle 53. In other words, the oil
throwers 19a and 19b may rotate relative to the axle 53.
[0058] The removal tools 31 may be other than rods. For example, the removal
tools 31 may be wires including threaded metal members attached at two ends. In
another example, the removal tools 31 may be cylindrical members. In this case, one
15 end of the cylindrical member may be fitted to the ring 13a or 13b.
[0059] The gear device may have any number of removal tools 31 or 35, rather than
the number in the above example.
The removal tools 31 or 35 may be fixed to the plate 33 in any manner other than
the manner described in the above example. In one example, the removal tools 31 or 35
20 may be attached to the plate 33 by a method such as welding, bonding with an adhesive,
or fitting.
[0060] The driver 32 may be any device, in place of a hydraulic cylinder, that can
urge the rings 13a, 13b, 25a, and 25b away from the follower gear 12.
[0061] The bearing remover 30 may have any structure that can urge the rings 13a,
25 13b, 25a, and 25b away from the follower gear 12.
[0062] The gear device 1 or 2 may be installed in any movable body such as an
automobile or a bus, or an industrial machine, in place of a railway vehicle.
18
[0063] The foregoing describes some example embodiments for explanatory
purposes. Although the foregoing discussion has presented specific embodiments,
persons skilled in the art will recognize that changes may be made in form and detail
without departing from the broader spirit and scope of the invention. Accordingly, the
5 specification and drawings are to be regarded in an illustrative rather than a restrictive
sense. This detailed description, therefore, is not to be taken in a limiting sense, and the
scope of the invention is defined only by the included claims, along with the full range of
equivalents to which such claims are entitled.
10 Reference Signs List
[0064] 1, 2 Gear device
11 Drive gear
12 Follower gear
12a, 12b Screw hole
15 13a, 13b, 25a, 25b Ring
14a, 14b, 34 Fastener
15 Gear box
15a, 15b Opening
16 Lid
20 17a, 17b Follower-shaft bearing
18a, 18b Bearing holder
19a, 19b Oil thrower
20 Earth ring
21a, 21b Inner race
25 22a, 22b Outer race
23a, 23b Rolling element
24a, 24b Through-hole
19
26a, 26b Lock
30 Bearing remover
31, 35 Removal tool
32 Driver
5 32a Rod
33 Plate
50 Truck
51 Motor
51a Shaft
10 52 Coupling
52a Drive shaft
53 Axle
54 Wheel

20
We Claim :
[Claim 1] A gear device, comprising:
a gear attached to a shaft to rotate integrally with the shaft;
a pair of bearings located across the gear in a direction in which the shaft extends,
5 the pair of bearings supporting the shaft in a rotatable manner; and
a plurality of removable members attached to two surfaces of the gear intersecting
with the shaft, each removable member of the plurality of removable members facing a
bearing of the pair of bearings located across the gear.
10 [Claim 2] The gear device according to claim 1, wherein
the plurality of removable members are attached to the two surfaces of the gear
intersecting with the shaft, and include two rings, at least a portion of each ring of the two
rings facing the pair of bearings.
15 [Claim 3] The gear device according to claim 2, wherein
each bearing of the pair of bearings includes an inner race, an outer race, and a
plurality of rolling elements held between the inner race and the outer race,
each of the two rings has an outer diameter larger than an inner diameter of the
outer race in each bearing of the pair of bearings at a surface of the outer race facing the
20 ring, and
each of the two rings has an inner diameter smaller than an outer diameter of the
inner race in each bearing of the pair of bearings at a surface of the inner race facing the
ring.
25 [Claim 4] The gear device according to any one of claims 1 to 3, wherein
each removable member of the plurality of removable members includes a device
receiver to which a bearing remover is attachable, and
21
the plurality of removable members are urged away from the gear by the bearing
remover attached to the device receiver to move away from the gear while at least a
portion of each removable member of the plurality of removable members is in contact
with the bearing facing the at least one removable member.
5
[Claim 5] The gear device according to claim 4, wherein
the device receiver includes a screw portion into which the bearing remover is
screwable.
10 [Claim 6] The gear device according to claim 4, wherein
the device receiver includes a fit portion to which the bearing remover is fittable.
[Claim 7] The gear device according to claim 4, wherein
the device receiver includes a lock on which the bearing remover is to be locked.
15
[Claim 8] The gear device according to any one of claims 4 to 7, further
comprising:
a gear box having an opening that is openable and closable, the gear box
accommodating the gear, the pair of bearings, and the plurality of removable members,
20 wherein
the bearing remover is attachable to the device receiver in each removable member
of the plurality of removable members through the opening.
[Claim 9] A bearing remover, comprising:
25 a removal tool attachable to the device receiver in each removable member of the
plurality of removable members included in the gear device according to any one of
claims 4 to 8; and
22
a driver to urge the removal tool away from the gear.
[Claim 10] A bearing removal method for removing a pair of bearings from a
gear device, the gear device including a gear attached to a shaft to rotate integrally with
5 the shaft, the pair of bearings located across the gear in a direction in which the shaft
extends and supporting the shaft in a rotatable manner, and a plurality of removable
members attached to two surfaces of the gear intersecting with the shaft, each removable
member of the plurality of removable members facing a bearing of the pair of bearings,
the method comprising:
10 urging the plurality of removable members away from the gear to move the
plurality of removable members away from the gear while each removable member of
the plurality of removable members is in contact with a bearing of the pair of bearings
facing the removable member of the plurality of removable members.
Dated this 18th day of September, 2023