JPS60135304A - Assembled structure of caster - Google Patents

Abstract

PURPOSE:To raise precision of the supporting part of a fixing shaft, and to set ball bearings always concentrically with the center of the fixing shaft, by forming a supporting yoke in an integrated one body by die casting. CONSTITUTION:A die cast supporting yoke 20 is constructed with a supporting block 21 and a pair of supporting plates 22, 22, which are extended diagonally from both lower sides of the block 21. In the center of the block 21, a fixing hole 23 is formed as it pierces through the upper part/the lower part of the block 21, and in this fixing hole 23, radial ball bearings 24, 24 are inserted with a spacer 24a between. Through the inner rings of the ball bearings 24, 24, a fixing shaft 25, the upper end of which is fixed to the side to be fixed, is inserted, and this fixing shaft 25 is supported with the upper end of the supporting yoke 20, as it can rotate freely. As the supporting yoke 20 is formed in an integrated one body by die casting, the precision of the supporting part of the fixing shaft 25 is raised, comparing with a press-processed supporting yoke.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a caster assembly structure in which there is no play in the mounting shaft and the number of parts can be reduced.

Conventional casters used for wheelchairs and the like generally have a structure as shown in FIG.

This caster includes a support yoke 1 with a wheel 2 rotatably supported at its lower end, and a mounting shaft 3 vertically mounted on the upper end of the support yoke 1.

At the upper end of the support yoke 1, a lower plate 4. A ball bearing 6 is disposed on the lower surface via an upper plate 5, and a ball bearing 9 is arranged on the lower surface via a ball race 7 and a lower plate 8.

Further, a flange portion 3a is formed on the upper side of the mounting shaft 3, and a nut 10 is attached to the lower end side, and these members hold the above-mentioned members and support the mounting shaft 3 so as to be rotatable on the yoke 1. are doing.

Note that the reference numeral 11 in the figure is a dustproof cover inserted between the flange portion 3a and the upper plate 5.

In the above configuration, the support yoke 1, the upper plate 5, and the lower plates 4, 8 are generally formed by press molding.

However, when each member is manufactured by press molding in this manner, the processing accuracy inevitably becomes low, and the following problems occur accordingly.

In other words, in order for the caster to move straight and turn with precision, the balls must be arranged concentrically with respect to the center of the mounting shaft.

However, in reality, due to machining tolerances on the race surface, the balls are not placed concentrically and accurately with respect to the center of the mounting shaft, which causes play in the shaft, impairing the straightness of the caster, and causing the caster to meander. There is a problem with the problem.

Further, since the support yoke 1 itself is formed by a press molding, it requires the above-mentioned discs, ball races, etc., which inevitably increases the number of parts and makes assembly complicated.

This invention was made to solve the above problems.
The purpose of the present invention is to prevent rattling from occurring in the mounting shaft, improve straightness, reduce the number of parts, and facilitate assembly.

In order to achieve the above object, the present invention provides a support yoke that is integrally formed by die-casting with a support block that supports the mounting shaft mounted on the number 1 side and a pair of support plates that rotatably support the wheels. a pair of upper and lower radial ball bearings that are fitted into mounting holes formed through the upper and lower portions of the support block and rotatably support the mounting shaft; and a lower end of the mounting shaft located on the bottom surface of the support block. The present invention is characterized by comprising a lower bearing holder fixed to the support block, and a cover that covers the upper surface of the support block and also serves as the upper bearing holder, which is integrally attached to the outer periphery of the mounting shaft.

An embodiment of the present invention will be described in detail below with reference to FIGS. 2 to 4.

In the figure, reference numeral 2O denotes a die-cast support yoke, and this support yoke 20 consists of a support block 21 and a pair of support plates 22 and 22 extending diagonally on both sides of the lower part of this support block 21. There is.

At the center of the support block 21 is a mounting hole 23 that passes through the top and bottom.
is formed, and a stepped portion 23a is formed at the center thereof.

Radial ball bearings 24, 24 are fitted into this mounting hole 23 from above and below via spacers 24a.

Each ball bearing 24 abuts against the stepped portion 23a and is positioned at a normal fitting position.

A mounting shaft 25 whose upper end is fixed to the mounted side is inserted into the inner ring of each ball bearing 24.

The lower bearing holder 26 is supported by the lower end of the mounting shaft 25 by fitting the lower bearing holder 26 into the lower protruding end of the mounting shaft 25 and attaching the nut 27 to the lower part thereof.

On the other hand, a dustproof cover 28 which also serves as a bearing holder is fitted onto the upper surface of the support block 21, and the upper surface of the dustproof cover 28 is pressed by a flange portion 25a integrated with the upper part of the shaft 25. The outer ring is clamped and fixed between the lower bearing holder 26 and the cover 28,
Pushed (pushed) into the correct position.

With the above configuration, the mounting shaft 25 is rotatably supported at the upper end of the support yoke 20.

Furthermore, a wheel 29 is rotatably supported at the tip of the support plate 22.

The support structure for this wheel 29 is shown in detail in FIG.

That is, a pair of spacers 31 and '31 are attached to the outer periphery of the support shaft 30 that is fixed to the support shaft 30 passing through the tip portions of the support plate 22.
The wheel 29 is rotatably supported at the tip of the support plate 22 by inserting a bearing 32.32 through the bearing 32 and inserting the center hole of the wheel 29 into the outer circumference of the bearing 32.

Note that since the support yoke 2o is formed by die-casting, the machining accuracy of the mounting holes 23 is high, and therefore the parallelism between the bearings 24 held therein is also extremely high. Therefore, the mounting shaft 25 rotatably supported thereon has no center runout.

As explained above, in the assembly structure of the caster according to the present invention, the support yoke is particularly integrally molded by die casting as described above, so that the mounting shaft can be easily fixed compared to the conventional press work. The precision of the support part can be improved at each step, and the ball bearing can always be placed concentrically with the center of the mounting shaft. Moreover, this improves the turning performance of the casters, and at the same time eliminates play in the mounting shaft, improving straight-line performance. therefore,
When this caster is applied to a wheelchair or the like, stable running performance can be obtained.

Furthermore, in the present invention, since the mounting holes can be integrally formed during die-casting, the number of parts for the support portion of the mounting shaft can be significantly reduced compared to conventional press working, and the ease of assembly is also improved.

Furthermore, the present invention provides a caster with a more luxurious appearance, with a sleeker appearance and significantly improved design performance, compared to a support yoke made of a conventional press-formed body.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional front view of a conventional wheelchair caster, FIG. 2 is a partially cross-sectional side view of a caster according to the present invention, and FIG.
The figure is a sectional view taken along the line ■--■ in FIG. 2, and FIG. 4 is an exploded perspective view of the same caster. 20...Support yoke 21...Support block 22...Support plate 23...Mounting hole 24...Ball bearing 25...Mounting shaft 28...Cover Patent applicant Nanshin Rubber Industries Co., Ltd. Figure 1

Claims (1)

[Claims] (1) The support block and wheels that support the mounting shaft mounted on the mounted side can be rotated freely. A support yoke integrally molded by die-casting with a pair of support plates that support the
a pair of upper and lower radial ball bearings that are fitted into mounting holes formed by passing the upper and lower parts of the support block and rotatably support the mounting shaft; and a pair of upper and lower radial ball bearings that are fixed to the lower end of the mounting shaft on the bottom surface of the support block. A caster assembly structure characterized by comprising a lower bearing holder with a lower bearing holder, and a cover that covers the upper surface of a support block and also serves as an upper bearing holder, which is integrally attached to the outer periphery of a mounting shaft.