JP4234669B2 - caster - Google Patents

Description

  The present invention relates to a caster provided at a lower portion of a carriage or the like.

2. Description of the Related Art Conventionally, as casters for bogies, there are known ones that can turn when a yoke having wheels comes around a turning shaft. In order to make the yoke rotatable with respect to the pivot axis, a bearing is fixed to the yoke, and the pivot axis is inserted into the bearing.
Japanese Patent Laid-Open No. 2002-2209

Conventionally, however, the yoke is only provided with a radial bearing, and all of the load applied to the turning shaft is received only by this radial bearing. In such a configuration, it is good if the load is applied only in the direction along the axis of the swivel axis, but if the swivel axis is twisted and the load is applied in a direction eccentric to the axis, An axial load is applied to the side surface of the inner ring.
Since the axial load is larger than the radial load in the swivel part of the caster, the bearing tends to have a dent, and smooth turning may not be possible.

  The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a caster that enables smooth turning even when the turning shaft rotates while twisting.

The caster of the present invention is a caster in which a yoke is provided so as to be able to turn around a turning shaft to which a mounting seat fixed to an attached body is attached, and the yoke is formed by bifurcating downwardly. A wheel is held between the support pieces, and a hole into which the turning shaft is inserted is formed in a central piece that connects the upper ends of the two support pieces. And a second bearing, wherein the first bearing is a thrust bearing in which an upper ring and a lower ring are spaced apart in the axial direction of the turning shaft, and the inner ring and outer ring of the second bearing are turned. Radial bearings are arranged spaced apart in the radial direction of the shaft, the yoke is made of resin, and the hole formed in the yoke has a large-diameter hole on the upper side through a step. Stepped holes with small diameter holes on the side The outer ring of the second bearing is held in the small-diameter hole of the yoke by insert molding, the first bearing is placed in the upper large-diameter hole, and the swivel shaft is sequentially moved upward from the upper end of the shaft body. The first enlarged diameter portion and the second enlarged diameter portion are formed by expanding the diameter, and the lower end portion of the shaft body is reduced in diameter to form the reduced diameter portion, and the mounting seat is formed by the first enlarged diameter portion. The lower end portion of the first enlarged diameter portion is fixed by being sandwiched between the caulked portion and the second enlarged diameter portion, and the lower end portion of the first enlarged diameter portion is placed on the upper ring of the first bearing. The reduced diameter portion is fitted into the inner ring of the second bearing, the lower end portion of the reduced diameter portion extends downward from the second bearing, and the extended reduced diameter portion is caulked and the caulking portion and the shaft main body are the lower end portion and by a second inner ring sandwiched pivot axis of the bearing and the inner ring of the second bearing, which are integrally rotatable And features.

  According to the caster of the present invention, by sharing the radial load and the axial load with separate bearings, the rotational resistance is reduced and smooth turning is possible.

  Hereinafter, the caster of the present invention will be described in more detail based on examples.

FIG. 1 is a perspective view showing a caster of this embodiment. FIG. 2 is a sectional view of the yoke.
The caster of the present embodiment includes a yoke 1 that rotatably holds a wheel 44 between two support pieces 3 and 3, and two bearings provided vertically apart in a hole 6 formed in the yoke 1. 10 and 15 and a turning shaft 20 inserted into the holes of the bearings 10 and 15.

  As shown in FIG. 1, the yoke 1 is formed in a downward substantially U-shape that opens downward. That is, the yoke 1 is integrally formed with an arc-shaped central piece 2 disposed so as to cover the upper end portion of the wheel 44 and a pair of support pieces 3 and 3 extending substantially vertically downward from both ends of the central piece 2. Has been. In the illustrated example, the support piece 3 has an inverted triangular shape.

  At one end portion (right end portion in FIG. 2) of the central piece 2 of the yoke 1, a cylindrical mounting portion 5 is formed so as to protrude upward. A hole 6 is formed in the attachment portion 5 so as to penetrate in the vertical direction. Two bearings 10 and 15 are provided in the hole 6 so as to be spaced apart from each other in the vertical direction, and the turning shaft 20 is rotatably inserted into the hole of each bearing 10 and 15 with respect to the yoke 1.

By the way, the yoke 1 of the present embodiment is integrally formed of resin. That is, the center piece 2, the support piece 3, and the attachment part 5 are integrally formed with resin.
Further, the hole 6 formed in the attachment portion 5 is a stepped hole 6, the first bearing 10 is provided in the upper large-diameter hole 7, and the second bearing 15 is provided in the lower small-diameter hole 8.

The second bearing 15 is a radial bearing in which a substantially cylindrical inner ring 16 and an outer ring 17 are configured to be rotatable via a rolling element 18. In this embodiment, a ball bearing, particularly a deep groove ball bearing is preferably used. The
When the yoke 1 is formed of resin, the outer ring 17 of the second bearing 15 is held on the outer peripheral portion of the small diameter hole 8 by insert molding. That is, by setting the second bearing 15 in the mold in advance, the yoke 1 is molded with the outer ring 17 embedded in the outer peripheral portion of the small diameter hole 8.

The first bearing 10 is a thrust bearing in which an annular plate-like upper ring 11 and lower ring 12 are configured to be rotatable via rolling elements 13, and a ball bearing is used in this embodiment.
The first bearing 10 is accommodated in the large diameter hole 7 of the stepped hole 6 and placed on the stepped portion 7a.
In the present embodiment, the diameter of the hole of the first bearing 10 is larger than the diameter of the hole of the second bearing 15 (inner diameter of the inner ring 16).

In this way, the turning shaft 20 is rotatably inserted into the yoke 1 in the holes 10 a and 15 a of the first bearing 10 and the second bearing 15 provided in the mounting portion 5.
FIG. 3 is a schematic cross-sectional view showing a state in which the turning shaft 20 is inserted into the mounting seat 30, and FIG. 4 is a cross-sectional view showing a state in which the turning shaft 20 to which the mounting seat 30 is fixed is inserted into the bearings 10 and 15. FIG. 5 is a cross-sectional view showing a state in which the turning shaft 20 is rotatably attached to the yoke 1.

  The turning shaft 20 of this embodiment is a stepped cylinder. That is, the upper end portion of the shaft body 21 of the turning shaft 20 is gradually expanded in diameter toward the upper side to form the first expanded portion 22 and the second expanded portion 23, while the lower end portion of the shaft body 21 is The reduced diameter portion 24 is formed by reducing the diameter.

The diameter of the shaft body 21 of the turning shaft 20 is slightly smaller than the diameter of the hole 10 a of the first bearing 10. The diameter of the reduced diameter portion 24 of the turning shaft 20 is adapted to the diameter of the hole 15a of the second bearing 15 (the inner diameter of the inner ring 16).
In the present embodiment, the turning shaft 20 is inserted into the bearings 10 and 15 of the yoke 1 in a state where the mounting seat 30 fixed to the attached body such as the carriage main body is attached to the turning shaft 20 in advance.

  As shown in FIG. 1, the mounting seat 30 of the present embodiment is formed in a substantially rectangular plate shape, and a truncated cone-shaped concave portion 31 is formed in the center of the mounting seat 30 and the diameter of the mounting seat 30 decreases as it goes downward. A through hole 33 is formed in the center of the bottom surface 32 of the recess 31 along the vertical direction. The diameter of the through hole 33 corresponds to the diameter of the first enlarged diameter portion 22 of the turning shaft 20. In addition, mounting holes 34 are formed at the four corners of the mounting seat 30 so as to penetrate in the vertical direction. This attachment hole 34 is used when a caster is attached to the attached body.

The turning shaft 20 is inserted into the through hole 33 of the mounting seat 30 from above, and the second enlarged diameter portion 23 is placed on the bottom surface 32 of the recess 31 of the mounting seat 30. And the lower end part of the 1st enlarged diameter part 22 is pressed and crimped upwards.
Thereby, the recessed portion bottom surface 32 of the mounting seat 30 is sandwiched between the caulking portion 22 a and the second enlarged diameter portion 23, and the mounting seat 30 is fixed to the turning shaft 20.

The turning shaft 20 to which the mounting seat 30 is fixed is inserted into the holes 10 a and 15 a of the bearings 10 and 15 of the mounting portion 5. In this embodiment, the turning shaft 20 is inserted in a state where the flat washer 40 is placed on the upper ring 11 of the first bearing 10.
In the state where the turning shaft 20 is inserted, the bottom surface 32 of the recess of the mounting seat 30 is placed on the upper ring 11 of the first bearing 10 via the plain washer 40. The lower end portion of the shaft body 21 of the turning shaft 20 is in contact with the upper surface of the inner ring 16 of the second bearing 15. Further, the reduced diameter portion 24 of the turning shaft 20 is fitted into the hole 15 a of the second bearing 15, and its lower end portion extends downward from the second bearing 15.

  The lower end portion of the reduced diameter portion 24 is caulked with the flat washer 41 being passed through the reduced diameter portion 24 extending downward from the second bearing 15. As a result, the inner ring 16 of the second bearing 15 is sandwiched between the caulking portion 24 a and the lower end portion of the shaft body 21, and the turning shaft 20 can rotate integrally with the inner ring 16 of the second bearing 15. That is, the turning shaft 20 is rotatable with respect to the yoke 1.

  An axle 43 is bridged between the pair of support pieces 3 and 3 of the yoke 1 provided with the turning shaft 20, and wheels 44 are rotatably held on the axle 43. The caster of the present embodiment is used with the mounting seat 30 fixed to the carriage body or the like.

The caster of the present embodiment having such a configuration is provided with two bearings of the thrust bearing 10 and the radial bearing 15 in the revolving part, so that the load applied to the revolving shaft 20 is shared and smooth revolving is possible. The That is, when a load is applied, a radial load is received by the radial bearing 15, and an axial load is received by both the thrust bearing 10 and the radial bearing 15. As a result, even when a tilting force acts on the shaft center during rotation of the turning shaft 20, the load is shared between the thrust bearing 10 and the radial bearing 15, and the rotational resistance is reduced. It becomes possible.
And by such a structure, the caster of a present Example suppresses the noise which generate | occur | produces at the time of the turning, and is used suitably for the conveyance by the trolley | bogie in a hospital or midnight.

  In addition, in the present embodiment, the yoke 1 is formed of resin, so that the second bearing 15 can be attached at the time of manufacturing the yoke 1 by insert molding. As a result, the assembly process can be reduced, and the manufacturing can be shortened.

  The caster of the present invention is not limited to the configuration of the above embodiment, and can be changed as appropriate. For example, in the said Example, although it was set as the structure which inserts the turning shaft 20 from the upper direction of the attaching part 5, it can also be set as the structure inserted from the downward direction. That is, a bolt-shaped swiveling shaft is inserted from below the mounting portion 5, a nut-shaped receiving plate is screwed into the tip end portion of the swiveling shaft, and this receiving plate is brought into contact with the upper ring of the thrust bearing.

  Moreover, in the said Example, although the mounting seat 30 was provided in the turning shaft 20, and it was set as the structure which attaches a caster to a cart main body etc. via this mounting seat 30, the structure which attaches the upper end part of a rotating shaft directly to a cart main body etc. It does not matter. In this case, a diameter-enlarged portion of the turning shaft or a bowl-shaped member attached to the turning shaft may be brought into contact with the upper ring of the thrust bearing.

It is a perspective view which shows one Example of the caster of this invention. It is sectional drawing of the yoke of the caster of FIG. It is a schematic sectional drawing which shows the state which inserted the turning axis in the mounting seat. It is sectional drawing which shows the state which inserts the turning axis | shaft with which the attachment seat was fixed to the bearing. It is sectional drawing which shows the state which attached the rotating shaft to the yoke so that rotation was possible.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Yoke 2 Central piece 3 Support piece 5 Mounting part 6 Stepped hole 7 Large diameter hole 8 Small diameter hole 10 First bearing 11 Upper ring 12 Lower ring 15 Second bearing 16 Inner ring 17 Outer ring 20 Rotating shaft 30 Mounting seat 44 Wheel

Claims (1)

A caster in which a yoke is provided so as to be able to turn around a turning shaft to which a mounting seat fixed to a mounted body is attached,
In the yoke, a wheel is held between both support pieces formed by bifurcating downward, and a hole into which a turning shaft is inserted is formed in a central piece that connects upper ends of both support pieces. And
The hole is provided with a first bearing and a second bearing spaced apart in the vertical direction,
The first bearing is a thrust bearing in which an upper wheel and a lower wheel are spaced apart from each other in the axial direction of the turning shaft,
The second bearing is a radial bearing in which an inner ring and an outer ring are spaced apart in the radial direction of the turning shaft,
The yoke is made of resin,
The hole formed in the yoke is a stepped hole in which a large diameter hole is formed on the upper side through a step and a small diameter hole is formed on the lower side,
The outer ring of the second bearing is held in the small-diameter hole of the yoke by insert molding,
The first bearing is placed on the upper large-diameter hole,
The swivel shaft gradually increases in diameter as it goes upward from the upper end of the shaft main body to form a first enlarged diameter portion and a second enlarged diameter portion. Formed,
The mounting seat is fixed by being sandwiched between a caulking portion formed by caulking a lower end portion of the first enlarged diameter portion and the second enlarged diameter portion,
The caulked portion at the lower end of the first enlarged diameter portion is placed on the upper ring of the first bearing,
The reduced diameter portion is fitted into the inner ring of the second bearing,
The lower end portion of the reduced diameter portion extends downward from the second bearing, and the inner ring of the second bearing is sandwiched between the caulked portion where the extended reduced diameter portion is caulked and the lower end portion of the shaft body, A caster characterized in that the inner ring of the second bearing can rotate integrally.

Images