JPH08188004A - Wheel fixing structure - Google Patents

Abstract

PURPOSE: To provide wheel fixing structure which has economical molding cost, is easy to fix, and capable of accurately, surely fixing. CONSTITUTION: An axial hole 21 of a wheel 20 has a large diameter hole 21A and a small diameter hole 21B formed with a mold 30 which moves in the axial line direction of the axial hole 21, and a circular projection 22 constituted with the small diameter part 21B formed so as to have step difference from the large diameter part 21A is engaged with a neck part 11 of an axle 10 which is inserted into the axial hole 21 from the side of a head 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel mounting structure which can be used as a twin-wheel type caster having an axle in a push-in engaged state.

[0002]

2. Description of the Related Art As a mounting means for a wheel in a caster having wheels on both sides of an axle, for example, an axle-wheel mounting structure shown in FIGS. 10 to 12 has been used.

The wheel mounting structure shown in FIG. 10 has an axle 1 inserted through a shaft hole 101 provided in the wheel 100.
02, the shaft end of the axle 102 protruding from the shaft hole 101 is attached to the boss portion 100a of the wheel 100 with a washer 103 or the like being appropriately interposed at the shaft end protruding from the shaft hole 101. It was assembled by a so-called crimping method of crushing and deforming 102a.

However, such a wheel mounting method requires a step of caulking the axle 102 inserted into the shaft hole 101 of the wheel 100 one by one, so that the wheel 100 is assembled. The caulking device is required, and the caulking process has a disadvantage that the boss portion 100a of the assembly wheel 100 is damaged. Moreover, in such a method,
For example, even when the axle 102 is inserted and set with the same central axis line into the shaft hole 101, it is convenient to use the assembly axle 1 in the caulking step.
The mounting axis of No. 02 may be distorted, which may cause a defective product in the assembly process such as casters.

From this point of view, recently, a press-fitting type wheel mounting means has been used which is easy to assemble, eliminates the occurrence of defective products in the assembly process, and reduces the assembly cost. This type of so-called axle 102 is used for the wheels 10
As a mounting structure of a wheel of a type that presses into and engages with the shaft hole 101 of No. 0, for example, as shown in FIGS. The neck portion 10 is provided with 104, and the axle 102 to be inserted into the shaft hole 101 is prepared.
2b and a head 102c formed between the neck 102b and the tip of the axle 102,
There is a wheel mounting structure in which the wheel 100 is mounted on the axle 102.

In such a wheel mounting structure, when the wheel 100 is a plastic molded product provided by molding using a synthetic resin material, the shaft hole 101 into which the axle 102 is inserted is Only by opening the molding die in the axial direction of the hole 101, together with the axial hole 101, the annular convex portion 10 in the circumferential direction inside the axial hole 101 is formed.
It has the feature that it can be molded in the same way as in No. 4. Further, in this case, the head portion 102c of the axle 102 that is pushed into the shaft hole 101 is simply forced into the annular convex portion 104 to force the head portion 102c into the annular convex portion 104.
From the top to the top, and this allows the axle 10
The annular convex portion 104 can be engaged with the neck portion 102b in 2 in a state of being guided in, and the wheel 100 can be immediately assembled to the axle 102.

[0007]

However, such a wheel mounting method, particularly when the axle 102 is assembled to the plastic molded wheel 100, the plastic molded wheel 100 is forcedly removed. In the configuration in which the annular convex portion 104 is provided and the annular convex portion 104 resulting from this forced removal is used as the engaging means of the axle 102 to be pushed in, it is accompanied by running when used as a caster or the like configured. Due to the rotation of the wheels, the annular projection 104, which is the engaging means of the axle 102, is worn, which causes the wheel 100 to rotate in a tilted state with respect to the axle 102.

Further, according to such a method, the axle 102
Annular protrusion 104 housed in the neck 102b of the
On the other hand, when the axle 102 comes into rotational contact while being applied with a force directed in the direction F of withdrawal, the annular convex portion 104 may be significantly worn or lost by this, so-called wheel removal. This may cause inconveniences such as.

The disadvantage of the conventional wheel mounting method is that the annular convex portion 104 of the shaft hole 101 used for preventing the axle shaft 102 from coming off is formed by so-called forced removal during plastic molding. Is. That is, in forming such a plastic, when a convex portion protruding from the inner wall surface of the so-called blind hole-shaped axial hole 101 is to be formed by die cutting of this molding die, The mold for forming 101 is configured to be able to be extracted from the forming shaft hole portion after the wheel 100 is molded. Moreover, when the molding die is removed, the convex portion inside the shaft hole 101 is formed. Since it is deformed, the annular convex portion 104 in the shaft hole 101 configured by such a molding die forced removal method is
As shown in FIG. 11 and FIG. 12, the protrusion size of the annular convex portion 104 configured to have an arc-shaped cross section and configured as the arc-shaped cross section is, for example, the highest protruding end of the annular convex portion 104. Up to 0.2
The limit is ˜0.3 mm, and it has been impossible to provide the annular convex portion 104 having a sufficient protrusion size by die-cutting molding by the forceful punching method.

From this point of view, the axle shaft 102 is provided with respect to the shaft hole 101 which is formed by the die forcing method.
1 is attached to the axle 102 and is used as shown in FIG.
When a load is generated in the direction of the arrow F of 2, the step surface between the neck portion 102b and the head portion 102c of the axle 102, in particular, the step edge on the side of the head portion 102c forms the arc-shaped cross section. The annular convex portion 104, in particular, the inner convex surface is in contact with the annular convex portion 104 in a line contact state.
There is a problem that the curved peripheral surface of No. 3 is easily ground as shown in FIG.

Further, since the annular convex portion 104 on which the head portion 102c of the axle 102 is caught does not have a sufficient protruding height, when an unexpected load is applied to the wheels such as casters. , This annular protrusion 1
04 is slipped out of the neck portion 102c of the axle 102, which may cause inconvenience such as so-called wheel removal.

The present invention has been proposed as a solution to the above disadvantages of the conventional wheel mounting structure. The molding cost is low, the assembly is easy, and the caulking machine and the like are used. An object of the present invention is to provide a wheel mounting structure capable of accurately and surely assembling a wheel without using it.

[0013]

SUMMARY OF THE INVENTION A wheel mounting structure according to the present invention is a wheel mounting structure for achieving the above-mentioned object. The wheel mounting structure has a neck portion formed by annular grooves provided at both ends in a circumferential direction. 11 includes an axle 10 having a head 12 between the neck portion 11 and the rod end, and a pair of wheels having an axial hole through which the axle 10 is inserted. In addition, the shaft hole 21 of the wheel 20 has a large-diameter hole portion 21A and a small-diameter hole portion 21B formed by a forming die 30 that moves in the axial direction of the shaft hole 21. Further, with respect to the neck portion 11 of the axle 10 which is pushed into the shaft hole 21 from the side of the head portion 12, the small diameter hole portion 2 provided in a step shape from the large diameter hole portion 21A.
The annular raised portion 22 of 1B is engaged.

Next, the wheel mounting structure according to the second aspect of the present invention is the wheel mounting structure according to the first aspect of the invention, wherein the step surface 14 of the head portion on the side of the neck portion 11 of the axle 10 to be pushed in is The surface 22a at the hole edge of the small-diameter hole portion 21B to be brought into contact is a surface orthogonal to the surface including the axis of the shaft hole 21.

[0015]

The wheel mounting structure has a neck portion 11 formed of annular grooves provided at both ends in the circumferential direction, and a head portion 12 is provided between the neck portion 11 and the rod end. Axle 10
And a pair of wheels having a shaft hole through which the axle 10 is pushed, the shaft hole 2 of the wheel 20 being provided.
1 is a mold 5 that moves in the axial direction of the shaft hole 21.
It has a large-diameter hole portion 21A and a small-diameter hole portion 21B formed by 0, and in such a constitution, with respect to the neck portion 11 of the axle 10 pushed into the shaft hole 21 from the head portion 12 side, The wheel 2 has the configuration in which the annular ridge portion 22 formed by the small diameter hole portion 21B provided in a step shape from the large diameter hole portion 21A is engaged.
0 is pushed into the shaft hole 21 and the shaft hole 21 is inserted into the shaft hole 21 with respect to the neck portion 11 of the shaft shaft 10.
The annular ridge portion 22 in is engaged and the wheel 20 is attached to the axle 10.

Further, the annular raised portion 2 provided in the shaft hole 21.
Since 2 is configured by the die cutting of the molding die 50 that is movable and opened in the axial direction of the shaft hole 21,
The annular ridge 22 provided in the shaft hole 21 can be configured to have any protruding ridge size.

Further, the annular raised portion 2 provided in the shaft hole 21.
Since 2 is configured by the die cutting of the molding die 50 that is movable and opened in the axial direction of the shaft hole 21,
The annular raised portion 2 configured as a die-cutting surface of this molding die
The shape of the raised side surface of No. 2, that is, the surface 22a at the opening edge of the small-diameter hole portion 21B with which the step surface 14 on the side of the neck portion 11 of the head portion 12 of the axle 10 abuts may be formed in any shape. it can.

Next, the shaft hole 2 into which the axle 10 is pushed is inserted.
Step surface 2 between the large diameter hole portion 21A and the small diameter hole portion 21B
The head 2 of the axle 10 and the annular ridge 22 can be brought into surface contact with each other by having a structure in which 2a is a surface orthogonal to the surface including the axis of the shaft hole 21.

[0019]

EXAMPLES Each example of a typical wheel mounting structure according to the present invention will be described in detail below. 1 to 4 show a wheel mounting structure according to the first embodiment, and FIGS. 5 to 9 show a second mounting structure.
1 shows a wheel mounting structure according to an embodiment.

The wheel mounting structure shown as the first embodiment is shown in FIG. 1 in a state in which the caster is mounted on a caster, with its principal parts broken away, and in FIG. 2, the caster thus constructed is shown. Seen from the top, FIG.
Then, this caster is shown from the side. or,
In FIG. 4, the molding state of the wheels forming the caster is shown by cutting the main part of the molding die.
Next, the wheel mounting structure shown as the second embodiment is shown in FIG. 5 in a state in which the caster is mounted on the caster, with its essential parts broken away, and in FIG. 6, the caster thus constructed is seen from the top. FIG. 7 shows the caster as viewed from the side, and further, in FIG. 8, for example, is shown as a cross section of an essential part of mounting the wheel on the axle of the caster, and in FIG. 9, the wheel used here is shown. It is shown by cross-sectioning a main part of a molding die in a molding state in which molding is performed.

First, a wheel mounting structure according to the first embodiment shown in FIGS. 1 to 4 will be described. Here, the wheel mounting structure configured has a neck portion 11 formed of annular grooves provided at both ends in a circumferential direction, and a head portion 12 is provided between the neck portion 11 and the rod end. And a pair of wheels 20 through which an axial hole into which the axle 10 is pushed are provided.
No. 0 shaft hole 21 is provided with a large-diameter hole portion 21A and a small-diameter hole portion 21B formed by a forming die 50 that moves in the axial direction of the shaft hole 21, and the head portion An annular ridge 2 formed by the small-diameter hole portion 21B provided stepwise from the large-diameter hole portion 21A with respect to the neck portion 11 of the axle 10 that is pushed into the shaft hole 21 from the 12 side.
2 is engaged.

In the wheel mounting structure, the surface 22a at the opening edge of the small-diameter hole portion 21B with which the step surface 14 on the neck portion 11 side of the head portion 12 of the axle 10 comes into contact is the shaft hole 21. The surface is orthogonal to the surface including the axis line.

The wheel mounting structure constructed here is constructed, for example, as a two-wheel caster as in the illustrated example. This twin-wheel caster has a boss portion 32 having a shaft hole 31 through which the axle 10 is inserted in a horizontal direction, and a mounting shaft called a stem at a position laterally separated from the axis of the shaft hole 31. 33 on the caster body 30 with 33 attached in the vertical direction, and on both sides of this boss 32,
It is constituted by a pair of wheels 20 assembled to the axle 10 inserted through the shaft hole 31 of the boss portion 32. still,
Reference numeral 34 in the figure indicates that the wheel 2 is attached to the boss portion 23 of the wheel 20.
By fitting from the outside of 0, this wheel 20
Is a decorative cap for covering the fitting portion of the axle 10 to which the vehicle is attached, and 35 is a decorative cover for covering the circumferential surface of the wheel 20 assembled to the boss 32 in the caster body 30. Is shown.

First, the axle 10 used here is a rod having a circular cross section which is inserted and assembled in the shaft hole 31 of the caster body 30, and is formed as an annular groove in the circumferential direction of both side portions thereof. A neck portion 11 is provided, and a portion between the neck portion 11 and the shaft end of the axle 10 is formed as a head portion 12.

More specifically, the axle 10 constructed here is formed as an annular groove, leaving portions to be the heads 12 on both side portions of a cylindrical axle body portion 10A having the same rod diameter. The neck portion 11 is configured, the neck portion 11 is a narrow-diameter rod portion, and a chamfer 12a is applied to a peripheral edge of a side end of the head portion 12, and the axle body portion 10A is provided.
A step surface 13 between the neck 11, a head 12 and the neck 1
The step surface 14 with respect to 1 is configured as a surface orthogonal to the surface including the axis of the axle 10.

Next, the wheel 20 mounted on the axle 10 is formed by plastic molding of a synthetic resin material or the like, especially by plastic molding, and the shaft hole 21 for mounting the axle 10 is formed at the center thereof. The constitutional boss portion 23 is provided and the wheel portion 24 is provided on the same central axis as the axis of the shaft hole 21.

The shaft hole 21 provided in the wheel 20 is
It is a circular hole, and on the side of the boss 32 in the caster body 30 to which the wheel 20 is assembled,
Large-diameter hole portion 21 in which the axle body portion 10A of the axle 10 is accommodated
A part is provided on the opposite side to the large-diameter hole part 21A, and a small-diameter hole part 21B is provided following the large-diameter hole part 21A. Is configured as a large-diameter hole portion 21A '.
1 is formed by die cutting when molding the wheel 20 with plastic.

Thus, the shaft hole 21 provided in the wheel 20
Is provided with a large-diameter hole portion 21A on the inside and a large-diameter hole portion 21A 'on the outside, and a small-diameter hole portion 22B is provided in a stepped shape. 21A '
The portion projecting in a stepped shape from the above is configured as an annular raised portion 22.

Further, the annular ridge portion 22 formed as a stepped protruding portion is a step surface as a surface orthogonal to the surface including the axis of the shaft hole 21 on the side of the large diameter hole portion 21A '. The surface 22a has a curved surface 22a, and the tapered stepped surface 22b is provided on the large diameter hole portion 21A side.

Thus, the shaft hole 21 formed in the wheel 20
When the axle 10 is pushed in from the side of the large diameter hole portion 21A of the shaft hole 21 in the wheel 20, the head 11 of the axle 10 is pushed in while deforming the annular ridge portion 22, and With the head 12 passing over the annular ridge 22, the annular ridge 22 is housed in the neck 11 of the axle 10, and the head 12 has a large-diameter hole 2
1A ', the neck portion 11 is fitted into the small diameter hole portion 21B, and the axle body 10A is fitted into the large diameter hole portion 21A, respectively.

In the illustrated example, the head 12 of the axle 10 has a large diameter hole 21A 'so that the head 12 does not project outward from the boss 23 of the wheel 20. It has a structure that can be conveniently accommodated inside, and the annular ridge 22 fits the neck 11 of the axle 10 with some play so that the annular ridge 22 has a stepwise width with respect to the stepped width of the neck 11. The ridge width of 22 is made small.

The wheel 20 having such a structure can be molded using, for example, a mold 50 as shown in FIG. In this mold 50, one mold 50 has a large diameter hole portion 21A of the shaft hole 21 and a small diameter hole portion 2 following the large diameter hole portion 21A.
1B is provided, and the other die 50 'is provided with the pin portion 5 for producing the large diameter hole portion 21A'.
2 is provided. As a result, the mold 50,
By opening 50 'in the axial direction of the shaft hole 21 of the wheel 20 to be created, the wheel 20 having the structure of the shaft hole 21 can be created.

In the axle mounting structure thus configured, the step surface 14 on the side of the neck 11 of the head 12 of the axle 10 has the large diameter hole portion 21A 'and the small diameter hole portion 21B.
It comes into surface contact with the step-like surface 22a between and. As a result, the head portion 12 of the axle 10 does not damage the annular raised portion 22 as a means for preventing the axle 10 from slipping off due to the rolling of the casters and the like.

5 and 9 show a wheel mounting structure according to the second embodiment. In the wheel mounting structure according to the second embodiment, the head portion 12 of the axle 10 projects from the boss portion 23 of the wheel 20, that is, the shaft hole 21 of the boss portion 23 has a large diameter hole portion. 21A and a small-diameter hole portion 21B, and the hole peripheral side surface of the shaft hole 21 in the small-diameter hole portion 21B is connected to the axle 10
It is configured as a surface 22a as an engaging surface of the head portion 12 in. That is, in the wheel mounting structure according to the second embodiment, there is no large-diameter hole portion 21A 'in the wheel mounting structure according to the first embodiment, and it corresponds to the large-diameter hole portion 21A'. The portion to be formed is the boss portion 23 of the wheel 20, and as a result, the surface 22a on the peripheral surface of the small diameter hole portion 21B in the boss portion 23 of the wheel 20 becomes the surface 22a in the first embodiment. It is configured as a corresponding surface 22a.

The wheel mounting structure according to the second embodiment constructed here has exactly the same structure as the wheel mounting structure according to the first embodiment except for the above points. The same or substantially the same components as those of the wheel mounting structure according to the first embodiment will be described with the same reference numerals. The wheel mounting structure shown in FIGS. 5 and 9 has a neck portion 11 formed of annular grooves provided at both ends in the circumferential direction, and the neck portion 1
An axle 10 having a head 12 between 1 and the rod end;
A molding die which is configured by a pair of wheels 20 through which an axial hole into which the axle 10 is pushed is provided, and in which the axial hole 21 of the wheel 20 moves in the axial direction of the axial hole 21. Axle 10 having a large-diameter hole portion 21A and a small-diameter hole portion 21B formed by 50, and pushed into the shaft hole 21 from the head portion 12 side.
With respect to the neck portion 11, the annular ridge portion 22 constituted by the small diameter hole portion 21B provided in a step shape from the large diameter hole portion 21A is engaged.

In the wheel mounting structure, the surface 22a at the opening edge of the small-diameter hole portion 21B with which the step surface 14 on the neck portion 11 side of the head portion 12 of the axle 10 abuts is the shaft hole 21. The surface is orthogonal to the surface including the axis line. That is, in this embodiment, the peripheral surface of the opening edge of the small diameter hole portion 22B formed by the boss portion 23 of the wheel 20 is
It is configured as a surface 22a orthogonal to a surface including the axis of the shaft hole 21, and as a result, the stepped surface 14 of the axle 10 is in contact with the surface 22a.

The wheel mounting structure constructed here is the same as in the first embodiment, and is, for example, a twin-wheel caster as in the first embodiment. The twin wheel caster provided with the wheel mounting structure according to the second embodiment has a boss portion 32 having a shaft hole 31 through which the axle 10 is inserted in a horizontal direction, and from the axis line of the shaft hole 31. On the caster body 30 in which a mounting shaft 33 called a stem is vertically mounted at a position separated laterally, and on both sides of the boss 32,
There is a caster or the like configured by a pair of wheels 20 assembled to the axle 10 inserted through the shaft hole 31 of the boss portion 32. Further, in such a caster, the cosmetic cap 34 that covers the fitting portion of the axle 10 to which the wheel 20 is attached by fitting the caster 34 from the outside of the wheel 20 to the boss portion 23 of the wheel 20. Can be used for the caster main body portion 30 including the cosmetic cover portion 35 for covering the circumferential surface of the wheel 20 assembled to the boss portion 32.

First, the axle 10 used here is a rod having a circular cross section which is inserted and assembled into the shaft hole 31 of the caster body 30, and is formed as an annular groove in the circumferential direction of both side portions thereof. A neck portion 11 is provided, and a portion between the neck portion 11 and the shaft end of the axle 10 is formed as a head portion 12.

More specifically, the axle 10 constructed here is formed as an annular groove by leaving the portions to be the heads 12 on both side portions of the cylindrical axle body portion 10A having the same rod diameter. The neck portion 11 is configured, the neck portion 11 is a narrow-diameter rod portion, and a chamfer 12a is applied to a peripheral edge of a side end of the head portion 12, and the axle body portion 10A is provided.
A step surface 13 between the neck 11, a head 12 and the neck 1
The step surface 14 with respect to 1 is configured as a surface orthogonal to the surface including the axis of the axle 10.

Next, the wheel 20 mounted on the axle 10 is formed by plastic molding of a synthetic resin material or the like, particularly by plastic mold molding, and the shaft hole 21 for mounting the axle 10 is formed at the center thereof. The constitutional boss portion 23 is provided and the wheel portion 24 is provided on the same central axis as the axis of the shaft hole 21.

The shaft hole 21 provided in the wheel 20 is
It is a circular hole, and on the side of the boss 32 in the caster body 30 to which the wheel 20 is assembled,
Large-diameter hole portion 21 in which the axle body portion 10A of the axle 10 is accommodated
A, and on the opposite side to this, a large-diameter hole 21A is provided following the large-diameter hole 21A. This shaft hole 21 is formed by die-cutting when the wheel 20 is molded with plastic. Configured.

Thus, the shaft hole 21 provided in the wheel 20
Has a small-diameter hole portion 22B formed in a stepped shape by the large-diameter hole portion 21A on the inner side and the surface 22a on the outer side of the boss portion 23. A portion protruding in a step shape is configured as an annular raised portion 22.

The annular raised portion 22 formed as a stepped protruding portion is a stepped surface on the boss portion 23 side that is orthogonal to the surface including the axis of the shaft hole 21. 22a to the surface 2 of the peripheral edge surface of the opening in the boss portion 23.
2a, and a tapered stepped surface 22b is provided on the large diameter hole portion 21A side.

Thus, the shaft hole 21 formed in the wheel 20
When the axle 10 is pushed in from the side of the large diameter hole portion 21A of the shaft hole 21 in the wheel 20, the head 11 of the axle 10 is pushed in while deforming the annular ridge portion 22, and With the head portion 11 passing over the annular ridge portion 22, the annular ridge portion 22 is housed in the neck portion 11 of the axle 10 and the head portion 12 has a small diameter hole portion 2.
1B, the stepped surface 14 of the head portion 11 abuts against the surface 22a in this state, and the axle body 10A is closely fitted in the large diameter hole portion 21A.

In the illustrated example, the head portion 12 of the axle 10 is constructed so as to project outward from the boss portion 23 of the wheel 20, and the annular raised portion 22 is
In order to fit the neck portion 11 of the axle 10 with a little play, the annular raised portion 22 with respect to the stepped width of the neck portion 11
The ridge width of each is made small.

The wheel 20 having such a structure can be molded by using a mold 50 as shown in FIG. 9, for example. In this mold 50, one mold 50 is
A structure having a large-diameter hole portion 21A of the shaft hole 21 and a pin portion 53 that creates a small-diameter hole portion 21B following the large-diameter hole portion 21A, and a surface of the other die 50 'that contacts the pin portion 53. There is. As a result, by opening the molds 50, 50 ′ in the axial direction of the shaft hole 21 of the wheel 20 to be produced, the wheel 20 having the structure of the shaft hole 21.
Can be produced.

In the axle mounting structure thus configured, the step surface 14 on the side of the neck 11 of the head 12 of the axle 10 is the surface 22a on the peripheral surface of the aperture of the small diameter hole 21B. However, they will come into surface contact with each other. As a result, as the caster or the like rolls, the head 12 of the axle 10 damages the annular ridge 22 with respect to the annular ridge 22 that functions as a means for preventing the axle 10 from slipping out. Never.

[0048]

EFFECTS OF THE INVENTION The wheel mounting structure according to the present invention is characterized by the above-mentioned structure, in particular, a pair of wheels 20 having a shaft hole 21 through which the axle 10 is inserted. The shaft hole 21 is configured to include a large diameter hole portion 21A and a small diameter hole portion 21B formed by a molding die 50 that moves in the axial direction of the shaft hole 21, and furthermore, the head portion 12 The annular ridge 22 formed by the small-diameter hole portion 21B provided stepwise from the large-diameter hole portion 21A is engaged with the neck portion 11 of the axle 10 that is pushed into the shaft hole 21 from the side. Therefore, by simply pushing the axle shaft 10 into the axle hole 21 of the wheel 20, the axle hole 2 is disengaged from the neck portion 11 of the axle shaft 10.
The annular ridge 22 in 1 is engaged, and the wheel 20 is immediately assembled to the axle 10.

Further, the annular raised portion 2 provided in the shaft hole 21.
Since 2 is configured by the die cutting of the molding die 50 that is movable and opened in the axial direction of the shaft hole 21,
The annular ridge 22 provided in the shaft hole 21 has a feature that it can be configured to have an arbitrary protruding dimension.

Further, the annular raised portion 2 provided in the shaft hole 21.
Since 2 is configured by the die cutting of the molding die 50 that is movable and opened in the axial direction of the shaft hole 21,
The annular raised portion 2 configured as a die-cutting surface of this molding die
2 has a feature that the shape of the raised side surface, that is, the surface 22a of the axle 10 on the side where the head portion 12 comes into contact can be configured as a surface having an arbitrary shape.

Next, the shaft hole 2 into which the axle 10 is pushed is inserted.
By configuring the surface 22a of the small-diameter hole portion 21B of 1 that is in contact with the head portion 12 as a surface orthogonal to the surface including the axis of the shaft hole 21, the head portion 12 of the axle 10 is formed.
And the annular raised portion 22 are in surface contact with each other.

Furthermore, the neck 1 of the head 12 on the axle 10
Since the step surface 14 on the side of 1 is brought into surface contact with the surface 22a on the peripheral surface of the opening of the small diameter hole 21B, this axle shaft is rolled along with the rolling of the caster or the like. The head portion 12 of 10 has a feature that the annular raised portion 22 is not damaged with respect to the annular raised portion 22 functioning as a means for preventing the axle 10 from slipping out.

[Brief description of drawings]

FIG. 1 is a fragmentary front view of a caster having a wheel mounting structure according to a first embodiment.

FIG. 2 is a plan view of the same.

FIG. 3 is a side view of the same.

FIG. 4 is a sectional view of an essential part showing a molding state of the wheel together with a mold.

FIG. 5 is a fragmentary front view of a caster having a wheel mounting structure according to a second embodiment.

FIG. 6 is a plan view of the same.

FIG. 7 is a side view of the same.

FIG. 8 is a sectional view of an essential part of a wheel mounting structure according to a second embodiment.

FIG. 9 is a sectional view of an essential part showing a molding state of the wheel together with a mold.

FIG. 10 is a sectional view of a main part of a conventional wheel mounting structure.

FIG. 11 is a sectional view of a main part of another conventional wheel mounting structure.

FIG. 12 is an enlarged sectional view of the main part.

[Explanation of symbols]

 10 Axle 11 Neck 12 Head 20 Wheel 21 Shaft Hole 21A Large Hole 21B Small Hole 22 Annular Ridge

Claims (2)

[Claims] 1. An axle having a neck formed of annular grooves provided at both ends in a circumferential direction and having a head between the neck and the rod end, and the axle being pushed in. And a pair of wheels having an axial hole extending therethrough, wherein the axial hole of the wheel is formed by a molding die that moves in the axial direction of the axial hole, and a large diameter hole portion and a small diameter hole are formed. An annular portion formed by the small diameter hole portion provided stepwise from the large diameter hole portion in the neck portion of the axle pushed into the shaft hole from the side of the head portion. A mounting structure for a wheel, characterized in that ridges are engaged. 2. The surface at the edge of the small-diameter hole portion that abuts against the stepped surface on the neck side of the head portion of the axle to be pushed in is a surface orthogonal to the surface including the axis of the shaft hole. The mounting structure for a wheel according to claim 1, wherein: