CN111038173B - Method for manufacturing wheel and wheel - Google Patents

Abstract

The invention provides a method for manufacturing a wheel and a wheel, which can inhibit rigidity from decreasing. The core (32) is inserted into an inner cylinder (34 a) of the bearing (34) in a state where the core (32) is formed in a straight line. The Jigs (JG) are inserted into the 2 jig insertion holes (32 e) of the straight line part (32 a) provided with the bearing (34), and the 2 claw parts (32 f) are respectively bent by the force applied by the tips of the 2 Jigs (JG). The inner tube (34 a) is fixed to the straight portion (32 a) by the bent 2 claw portions (32 f), respectively. After the bearing (34) is fixed to the linear portion (32 a) by the respective 32 linear portions (32 a), the core (32) is bent in the inner direction at the 31 cut portions (32 b) to form the core (32) into a 32-sided shape, and the two engaging protrusions (32 j) of the linear portion (32 a) on one end side are inserted into and engaged with the 2 engaging holes (32 k) of the linear portion (32 a) on the other end side.

Description

Method for manufacturing wheel and wheel

Technical Field

The present invention relates to a method for manufacturing a wheel and a wheel.

Background

In recent years, a vehicle that is movable not only in the front-rear direction but also in all directions has been known. For example, japanese patent application laid-open No. 2001-213103 discloses wheels (casters) for enabling a vehicle to move in all directions.

The wheel includes a1 st wheel rotatable about a1 st axis extending in a left-right direction of the vehicle and a 2 nd wheel rotatable about a 2 nd axis extending in parallel with a tangential line of the 1 st wheel, and the 2 nd wheels are provided in plurality and attached to an outer side of the 1 st wheel at a predetermined angular interval.

In the wheel disclosed in japanese unexamined patent publication No. 2001-213103, a shaft member (small diameter shaft) rotatably supporting the 2 nd wheel is divided into a plurality of parts, and each of the parts is fixed to the 1 st wheel. Therefore, the plurality of shaft members are not connected, the rigidity of the entire wheel is low, and there is a problem in that the positional relationship between the plurality of shaft members is deviated. In addition, since it is necessary to fix each of the plurality of shaft members to the 1 st wheel, the number of working steps increases.

Disclosure of Invention

The present invention has been made in view of such circumstances, and an object thereof is to provide a method for manufacturing a wheel and a wheel capable of suppressing a decrease in rigidity.

Means for solving the problems

A wheel according to the present invention is a wheel including a ring-shaped 1 st wheel rotatable about a1 st axis as a rotation center, and a plurality of 2 nd wheels arranged at predetermined intervals in an outer circumferential direction of the 1 st wheel, the 2 nd wheels being rotatable about a 2 nd axis parallel to a tangential line tangent to an outer surface of the 1 st wheel, the wheel including: a placement step of placing the 2 nd wheel on each of a plurality of straight line portions extending between the adjacent cutout portions of the linear shaft member, wherein the cutout portions are formed in a shape cut away in an orthogonal direction orthogonal to the extending direction; a bending step of bending the shaft member along the plurality of cutouts, respectively; and a joining step of joining the straight portions at both ends of the shaft member, which are respectively bent along the plurality of cutouts, to each other in the bending step to form the 1 st wheel having a polygonal shape. The orthogonal direction orthogonal to the extending direction also includes a direction substantially orthogonal to the extending direction.

According to the method for manufacturing a wheel of the present invention, the polygonal wheel 1 can be easily manufactured by bending the shaft member extending in a straight line along the plurality of notched portions. This can simplify the manufacturing process as compared with a case where the shaft member is curved in an arc shape. Further, after bending the linear shaft member, only the both end portions of the shaft member are joined (only at joint 1), so that the polygonal wheel 1 can be easily manufactured.

Further, since the shaft member (1 st wheel) to which the 2 nd wheel is attached is constituted by 1 member in succession, a decrease in rigidity can be suppressed as compared with a case where the shaft member is constituted by connecting a plurality of members. Further, since the portion (linear portion) of the shaft member to which the 2 nd wheel is attached can be formed in a linear shape, the structure of the attachment portion of the 2 nd wheel can be simplified as compared with the case where the 2 nd wheel is attached to the arcuate portion. For example, in the case where the bearing for supporting the 2 nd wheel so as to be rotatable is mounted on the shaft member, the shape of a mounting member (not shown) for mounting the bearing can be simplified.

It is preferable that the wheel 2 is rotatably attached to the straight portion by performing the bending step after the disposing step, and thus the wheel including the wheel 1 and the plurality of wheels 2 rotatably attached to the wheel 1 can be manufactured. Further, the mounting step of rotatably mounting the 2 nd wheel is not required to be provided separately from the bending step, and man-hours can be reduced as compared with the case where the mounting step is provided separately from the bending step.

Further, it is preferable that the method further comprises a mounting step of mounting the 2 nd wheel to each of the plurality of straight portions so as to be rotatable about the 2 nd axis as a rotation center.

According to this configuration, since the mounting step is provided in addition to the bending step, the shaft member can be bent (bending step) at each of the plurality of notch portions after the 2 nd wheel is mounted (mounting step is performed) in its entirety. Thus, when the 2 nd wheel is mounted (mounting step), the shaft member is formed in a straight line before the bending step, and the 2 nd wheel is mounted more easily than in a state where the shaft member is bent. The mounting step may be performed at any timing.

In the mounting step, the 2 nd wheel rotatably supported by the bearing is rotatably mounted to the linear portion by bending a claw portion formed to be bendable on the shaft member, and fixing the bearing to the linear portion by abutting the claw portion to the bearing.

According to this structure, the bearing can be fixed only by bending the claw portion formed on the shaft member, and therefore, it is not necessary to use a separate member for fixing the position of the bearing, and an increase in the number of members can be prevented.

Further, it is preferable that the claw portion is provided on each of the plurality of straight portions, and the claw portion abuts against the bearing when the straight portions are bent along the cutout portion.

According to this configuration, the claw portion can be provided so as to protrude from the end portion of the straight portion, and the claw portion can be easily bent as compared with a case where the claw portion is provided in the center portion of the straight portion or the like.

The wheel of the present invention is characterized by comprising: a1 st wheel and a plurality of 2 nd wheels, wherein the 1 st wheel is a wheel in which a plurality of shaft members extending in a straight line and having cutout portions formed at predetermined intervals are respectively bent along the plurality of cutout portions and both end portions of the shaft members are joined to form a polygon, and the cutout portions have a shape cut away in an orthogonal direction orthogonal to the extending direction; the plurality of 2 nd wheels are rotatably mounted on a plurality of straight portions of the 1 st wheel between the adjacent cutout portions, respectively, with a 2 nd axis parallel to a tangent line tangent to the outer surface of the 1 st wheel as a rotation center.

According to the wheel of the present invention, the shaft member (1 st wheel) to which the 2 nd wheel is attached is constituted by one continuous member, and therefore, a decrease in rigidity can be suppressed as compared with a case where the shaft member is constituted by connecting a plurality of members. Further, since the portion of the shaft member to which the 2 nd wheel is attached can be formed in a straight line, the structure of the attachment portion of the 2 nd wheel can be simplified as compared with the case where the 2 nd wheel is attached to the arcuate portion. For example, when a bearing rotatably supporting the 2 nd wheel is attached to the shaft member, the shape of an attaching member (not shown) to which the bearing is attached can be simplified.

In addition, it is preferable that the wheel includes a plurality of bearings rotatably supporting the 2 nd wheels, each of the plurality of bearings, a claw portion extending in an extending direction of the shaft member and bendable in the orthogonal direction is provided on the shaft member, and the claw portion bent in the orthogonal direction is abutted against the bearing to fix the bearing to the linear portion, whereby the 2 nd wheel rotatably supported by the bearing is rotatably attached to the linear portion.

According to this structure, it is unnecessary to use a separate member for fixing the position of the bearing, and the number of members can be prevented from increasing.

Further, it is preferable that the claw portion is bent radially inward of the 1 st wheel in the orthogonal direction, and the bearing is fixed to the linear portion.

According to this structure, since the radially outer portion of the 1 st wheel is pressed against the straight portion, the inner surface of the bearing can absorb the difference in the bearing inner diameter (ば) by being located radially inward. This can suppress the difference in the ground contact surface caused by the difference being located outward.

Further, it is preferable that the claw portions are provided in the plurality of straight portions, respectively, and the claw portions come into contact with the bearing when the straight portions are bent along the cutout portions.

According to this configuration, for example, the claw portion that fixes the bearing to the 1 st linear portion can be provided so as to protrude from the end portion of the linear portion, and the claw portion can be easily bent as compared with a case where the claw portion is provided at the central portion of the linear portion or the like.

Further, it is preferable that a stress relaxation hole for relaxing stress at the bending portion when bending is performed at the notch portion is formed at an end portion of the notch portion in the cutting direction.

According to this structure, the stress of the bending portion can be relaxed, and the breakage of the shaft member due to the stress concentration generated when the shaft member is bent at the notch portion can be suppressed.

Drawings

Fig. 1 is a side view showing a wheel having a core bent into a 32-sided shape, free rollers and bearings.

Fig. 2 is a side cross-sectional view showing a wheel having a core bent into a 32-sided shape, free rollers, and bearings.

Fig. 3A is a side view showing a linear core.

Fig. 3B is a plan view showing a linear core.

Fig. 3C is a bottom view showing the linear core.

Fig. 4 is a perspective view showing a core.

Fig. 5A is a cross-sectional view showing a state in which a bearing is provided in a straight portion of a core.

Fig. 5B is a cross-sectional view showing a state in which the claw portion of the straight portion of the core is bent to fix the bearing.

Fig. 6 is a side view showing a wheel having a 22-sided folded core, free rollers and bearings of the second embodiment.

Fig. 7 is a bottom view showing a linear core according to the second embodiment.

Fig. 8A is a cross-sectional view taken along line IX-IX in fig. 7 showing a state in which a bearing is provided in a straight portion of a core body of the second embodiment.

Fig. 8B is a cross-sectional view taken along line IX-IX in fig. 7 showing a state in which the claw portion of the straight portion of the core body of the second embodiment is bent to fix the bearing.

Fig. 9A is a side view showing a linear core according to the third embodiment.

Fig. 9B is a plan view showing a linear core according to the third embodiment.

Fig. 9C is a bottom view showing a linear core according to the third embodiment.

Fig. 10A is a cross-sectional view showing a state in which a bearing is provided in a straight portion of a core body according to the third embodiment.

Fig. 10B is a cross-sectional view showing a state in which the claw portion of the straight portion of the core body of the third embodiment is bent to fix the bearing.

Detailed Description

An embodiment of a wheel according to the present invention will be described below with reference to fig. 1 to 5.

First embodiment

As shown in fig. 1 to 3, the main wheel 30 (wheel) of the present embodiment has a polygonal core 32 (wheel 1) and a plurality of free rollers 60 (wheel 2) rotatably mounted on the core 32.

The main wheel 30 is provided rotatably about an axis (1 st axis) extending in the left-right direction, and the plurality of free rollers 60 are provided rotatably about an axis (2 nd axis) parallel to a tangent line tangent to the outer surface of the polygonal core 32, and the plurality of free rollers 60 are arranged at predetermined intervals in the outer peripheral direction of the polygonal core 32, which will be described later.

The main wheel 30 is rotatably mounted on an inverted pendulum type vehicle (for example, an inverted pendulum type vehicle described in japanese patent application laid-open No. 2016-203681) for use, for example. The inverted pendulum type vehicle mounted with the main wheel 30 moves in the front-rear direction, for example, by the rotation of the polygonal core 32, and moves in the left-right direction, for example, by the rotation of the free roller 60 that contacts the ground. Thus, the inverted pendulum type vehicle can move in all directions by controlling the rotation of the polygonal core 32 and the free roller 60.

In the present embodiment, the core 32 is formed in, for example, a 32-sided polygon, and is divided into 32 straight portions 32a. As described in detail later, the bearings 34 are mounted on the 32 straight portions 32a, and the free rollers 60 are rotatably mounted on the bearings 34.

As shown in fig. 3A, the core 32 (shaft member) formed in a straight state is formed with 31 cutout portions 32b at a predetermined pitch, and the cutout portions 32b are formed in a shape cut out like an orthogonal direction (up-down direction in fig. 3A) orthogonal to the extending direction (left-right direction in fig. 3A) of the core 32. The core 32 is made of, for example, metal (e.g., stainless steel), and the slit portion 32b is formed by laser cutting the tubular core 32.

The straight line portion 32a (32) is formed between (30) the left side portion of the cutout portion 32b on one end side (left end side in fig. 3A) of the 31 cutout portions 32b, the right side portion of the cutout portion 32b on the other end side (right end side in fig. 3A), and the adjacent cutout portions 32b of the 31 cutout portions 32 b.

The left side of the straight portion 32a at the left side end is formed in the same shape as the right side portion of the left-right direction center portion of the cutout portion 32 b. The right side of the straight portion 32a at the right side end is formed in the same shape as the left side portion of the left-right direction center portion of the cutout portion 32 b.

The notch portions 32b are formed at angles (for example, 11.25 °) that enable the core 32 to be formed into a 32-sided shape when the core 32 is bent at 31 notch portions 32b, respectively. The 32 notched portions 32b are formed at an angle of about 330 ° in the circumferential direction of the core 32. Therefore, each linear portion 32a is connected to the adjacent linear portion 32a at an angle of about 30 °.

In the case where the straight portion 32a is formed in a 32-sided shape, it has an outer surface 32c constituting the outer peripheral surface and an inner surface 32d constituting the inner peripheral surface. The outer surface 32c has 2 jig insertion holes 32e for inserting jigs JG (see fig. 5B) described in detail below.

Rectangular claw portions 32f are formed on the inner surface 32d at positions corresponding to the 2 jig insertion holes 32e, respectively. The 2 claw portions 32f are formed in a shape symmetrical to the left and right in fig. 3A to 3C.

The inner surface 32d is formed with a notch 32g, and the notch 32g is formed continuously around 3 sides except 1 side on the outer side in the left-right direction among 4 sides constituting the rectangular claw portion 32f. The number of notches 32g is 2 corresponding to the number of 2 claws 32f, and the notches are formed in a shape symmetrical to the left and right in fig. 3A to 3C, similarly to the number of 2 claws 32f. Thereby, the 2 claw portions 32f can be bent (deformed) in the up-down direction (the radial direction of the main wheel 30).

Cut-portion stress relaxation holes 32h are formed at both circumferential end portions of the cut-portion 32b extending in the circumferential direction of the core 32, and the cut-portion stress relaxation holes 32h serve to relax stress at the cut-portion 32b when the straight portion 32a is bent at the cut-portion 32 b.

A claw stress relaxation hole 32i is formed at both end portions of the notch 32g, and the claw stress relaxation hole 32i is used to relax stress at the claw portion 32f when bending the claw portion 32f.

An engagement projection 32j protruding in the left direction (circumferential direction) is formed on the linear portion 32a on one end side (left end side in fig. 3A to 3C) of the 32 linear portions 32a. The engaging protrusions 32j are formed 2 at a pitch of 180 °.

The engagement projection 32j includes a linear projection 32j1 extending in a linear shape and an arc projection 32j2 connected to the tip of the linear projection 32j 1. In a state before the straight portion 32a is bent (see fig. 3A), the engagement protrusion 32j is formed such that the straight protrusion 32j1 extends obliquely downward.

The linear portion 32a on the other end side (right end side in fig. 3A to 3C) of the 32 linear portions 32a is formed with 2 engagement holes 32k into which the engagement protrusions 32j are inserted and engaged.

The engaging holes 32k are formed in 2 numbers corresponding to the 2 engaging protrusions 32j. The engagement hole 32k includes a linear hole 32k1 into which the linear protrusion 32j1 is inserted and an arcuate hole 32k2 into which the arcuate protrusion 32j2 is inserted. In a state before the straight portion 32a is bent (see fig. 3A), the engagement hole 32k is formed such that the straight hole 32k1 extends obliquely upward. In fig. 4, a manner in which the linear portion 32a provided with the engagement protrusion 32j is opposed to the linear portion 32a provided with the engagement hole 32k is schematically depicted.

As shown in fig. 5A, the bearing 34 is a known ball bearing, and a detailed description thereof is omitted. The bearing 34 includes an inner tube 34a, an outer tube 34b, and a plurality of balls 34c provided between the inner tube 34a and the outer tube 34b. Tapered portions 34b that slope outward from the inner peripheral surface toward the outer peripheral surface are formed at both end portions of the inner peripheral surface of the inner tube 34 a.

In the present embodiment, the inner tube 34a is fixed to the linear portion 32a, and the outer tube 34b is rotatably attached to the inner tube 34a via the balls 34c. The free roller 60 is fixed to the outer tube 34b.

[ manufacturing Process of Main wheel 30 ]

In manufacturing the main wheel 30, as shown in fig. 5A, the operator first inserts the core 32 into the opening of the inner tube 34a of the bearing 34 to which the free roller 60 is rotatably attached in a state in which the core 32 is formed in a straight line as shown in fig. 3A. For example, in the present embodiment, the bearing 34 (free roller 60) is provided at the straight portion 32a on the right end side. The bearing 34 (free roller 60) is provided in the center portion of the linear portion 32a in the lateral direction.

Next, as shown in fig. 5B, the operator inserts the jigs JG into the 2 jig insertion holes 32e provided with the straight portions 32a of the bearing 34, respectively, and brings the tips (lower ends) of the 2 jigs JG into contact with the 2 claw portions 32f, respectively. In this state, force is applied to the 2 jigs JG from above (e.g., striking with a hammer), respectively. Thereby, the 2 claw portions 32f are respectively bent downward along the notch 32 g.

The 2 claw portions 32f bent downward are respectively abutted against tapered portions 34d formed on the inner peripheral surface of the inner tube 34a of the bearing 34. Thereby, the inner tube 34a of the bearing 34 is fixed to the linear portion 32a.

By performing the steps (the disposing step and the mounting step) of disposing and fixing the bearings 34 to the linear portions 32a on the respective 32 linear portions 32a, the bearings 34 are fixed to the respective 32 linear portions 32a in a state where the core 32 is formed in a linear shape.

Next, the operator bends the core 32 in the inward direction at each of the 31 cut portions 32b, and forms the core 32 into a 32-sided shape (bending step). The inner direction refers to the lower direction in fig. 3A.

When the operator forms the core 32 into a 32-sided shape, as shown in fig. 4, 2 engagement protrusions 32j formed on the straight portion 32a on one end side (left end side in fig. 3A to 3C) are inserted into 2 engagement holes 32k formed on the straight portion 32a on the other end side (right end side in fig. 3A to 3C), respectively, and engaged with each other (engagement step). Thereby, the core 32 is held in the shape of a 32-sided figure (see fig. 1 and 2).

Further, after the core 32 is formed in a 32-sided shape, the side surfaces of the 32 straight portions 32a are in contact with the side surfaces of the adjacent straight portions 32a. The operator joins the abutted portions, for example, by welding. Thereby, the main wheel 30 having the 32-sided polygon core 32 and the free rollers 60 rotatably mounted on the 32 straight portions 32a of the core 32, respectively, is manufactured.

According to such a manufacturing method, the core 32 (1 st wheel) having a 32-sided shape (polygon shape) can be easily manufactured by bending the core 32 (shaft member) extending in a straight line at the 31 (plural) cutout portions 32b, respectively, and therefore, the manufacturing process can be simplified as compared with the case where the core 32 is curved in an arc shape.

Further, since the core 32 to which the free roller 60 (the 2 nd wheel) is attached is constituted by 1 continuous member, a decrease in rigidity can be suppressed as compared with a case where the core is constituted by connecting a plurality of members. Further, since the portion of the core 32 to which the free roller 60 is attached can be formed in a straight line (the straight line portion 32 a), the structure of the attachment portion (the bearing 34) of the free roller 60 can be simplified as compared with a structure in which the free roller 60 is attached to an arc-shaped portion.

Further, since the core 32 is bent at the 31 cut portions 32b after the 32 free rolls 60 are respectively attached to the 32 straight portions 32a, the core 32 is formed in a straight shape when the free rolls 60 are attached, and the free rolls 60 are more easily attached than in a state in which the core 32 is bent.

Further, since the bearings 34 (the free rollers 60) can be fixed in position by bending only 2 claw portions 32f, it is not necessary to use a separate member for fixing the bearings 34, and an increase in the number of components can be prevented.

Further, since the notch stress relaxing holes 32h are formed at both end portions in the circumferential direction of the notch 32b, when the straight line portion 32a is bent at the notch 32b, the stress at the notch 32b can be relaxed. This can prevent the core 32 from being broken due to stress concentration when the straight portion 32a is bent at the notch portion 32 b.

Further, since the claw portion stress relaxing holes 32i are formed at both end portions of the notch 32g for bending the claw portion 32f, the stress generated at the claw portion 32f when bending the claw portion 32f can be relaxed. This can suppress breakage of the core 32 due to stress concentration when bending the claw portion 32f.

Second embodiment

In the second embodiment shown in fig. 6 to 8, the wheel 100 has a polygonal core 102 (1 st wheel) (shaft member). The wheel 100 is formed to have a smaller diameter than the main wheel 30 of the first embodiment, for example, and is used for an AGV (Automatic Guided Vehicle: automatic guided vehicle). The same components as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

In the present embodiment, for example, the core 102 is formed in a 22-sided polygon, and is divided into 22 linear portions 102a. Bearings 104 are attached to the 22 linear portions 102a, respectively, and a free roller 110 (wheel 2) is rotatably attached to the bearings 104.

As shown in fig. 7, the core 102 is configured in the same manner as the core 32, and 21 notched portions 102b similar to the notched portions 32b of the core 32 are formed at predetermined intervals.

When the core 102 is bent at 21 cut portions 102b, the cut portions 102b are formed at an angle (for example, 16.4 °) forming a 22-sided polygon.

The linear portion 102a has an outer surface 102c and an inner surface 102d, and is formed with a1 st claw portion 102f1, a 2 nd claw portion 102f2, a1 st notch 102g1, a 2 nd notch 102g2, a notch stress relaxation hole 102h, an engagement protrusion 102j, and an engagement hole 102k, similarly to the linear portion 32a of the first embodiment. The linear portion 102a is not provided with holes corresponding to the jig insertion hole 32e and the claw-portion stress relaxation hole 32i of the first embodiment.

The 1 st claw portion 102f1 protrudes leftward from the left side surface of the linear portion 102a in fig. 7, and the 2 nd claw portion 102f2 protrudes rightward from the right side surface of the linear portion 102a in fig. 7. The 1 st claw portion 102f1 and the 2 nd claw portion 102f2 are provided at different positions in the circumferential direction of the core 102.

The 1 st notch 102g1 is cut away from the left side surface of the linear portion 102a in the inward direction in fig. 7, and the 2 nd notch 102g2 is cut away from the right side surface of the linear portion 102a in the inward direction in fig. 7.

The 1 st notch 102g1 and the 2 nd notch 102g2 are formed in such a size that they can be inserted into the 2 nd claw portion 102f2 and the 1 st claw portion 102f1 of the adjacent straight portion 102a.

The engagement projection 102j includes a linear projection and an arcuate projection as in the engagement projection 32j of the first embodiment. The engagement hole 102k has a straight hole and an arc hole, similar to the engagement hole 32k of the first embodiment.

As shown in fig. 8A, the bearing 104 is a known ball bearing, and a detailed description thereof is omitted. The bearing 104 includes an inner tube 104a, an outer tube 104b, and a plurality of balls 104c disposed between the inner tube 104a and the outer tube 104 b. Tapered portions 104d that slope outward from the inner peripheral surface toward the outer peripheral surface are formed at both end portions of the inner peripheral surface of the inner tube 104a.

In the present embodiment, the inner tube 104a is fixed to the linear portion 102a, and the outer tube 104b is rotatably attached to the inner tube 104a via the balls 104c. The free roller 110 is fixed to the outer cylinder 104b of the bearing 104.

[ manufacturing Process of wheel 100 ]

In manufacturing the wheel 100, an operator first inserts the core 102 into the openings of the inner cylinders 104a of the 2 bearings 104 in a state where the core 102 is formed in a straight line, and the free rollers 110 are rotatably attached to the 2 bearings 104. For example, in the present embodiment, the bearing 104 (free roller 110) is provided on the 2 nd straight portion 102a from the right end.

Then, the operator bends the 2 nd claw portion 102f2 of the 2 nd straight portion 102a from the right end. The 2 nd claw portion 102f2, which is bent at this time, serves to fix the bearing 104 to the straight portion 102a on the side (right end), and thus bending is performed in advance.

Next, as shown in fig. 8A, the operator bends the 1 st claw portion 102f1 of the right-end straight portion 102a, and thereafter bends the right-end straight portion 102a in the inward direction. Then, the 1 st claw portion 102f1 of the straight portion 102a at the right end is brought into contact with the tapered portion 104d on the right side in fig. 8A of the bearing 104.

Further, the operator bends the 1 st claw portion 102f1 of the 2 nd straight portion 102a from the right end. The 1 st claw portion 102f1, which is bent at this time, serves to fix the bearing 104 to the straight portion 102a on the side (3 rd from the right end), and thus bending is performed in advance.

Then, as shown in fig. 8B, after the operator bends the 2 nd claw portion 102f2 of the 3 rd straight portion 102a from the right end, the 3 rd straight portion 102a from the right end is bent in the inward direction. By this bending process, the bent 2 nd claw portion 102f2 of the 3 rd straight portion 102a from the right end abuts against the tapered portion 104d on the left side in fig. 8B of the bearing 104. Thereby, the bearing 104 is fixed to the 2 nd straight portion 102a from the right end.

By fixing the bearing 104 to the linear portion 102a (disposing step, bending step) for each of the 22 linear portions 102a, the bearing 104 is fixed to each of the 22 linear portions 102a in a state where the core 102 is formed in a 22-sided shape. In the present embodiment, the free roller 110 is rotatably mounted by performing the bending step after the disposing step. That is, the mounting step performed separately from the bending step is not provided.

In the present embodiment, for example, the bearing 104 provided in the 3 rd straight portion 102a from the right end is fixed by the 1 st bent claw portion 102f1 of the 2 nd straight portion 102a from the right end and the 2 nd bent claw portion 102f2 of the 4 th straight portion 102a from the right end.

The bearing 104 provided in the right end straight portion 102a is fixed by the 1 st bent claw portion 102f1 of the left end straight portion 102a and the 2 nd bent claw portion 102f2 of the 2 nd straight portion 102a from the right end.

When the operator forms the core 102 into a 22-sided shape, 2 engagement protrusions 102j formed on the straight portion 102a on one end side (left end side in fig. 7) are inserted into 2 engagement holes 102k formed on the straight portion 102a on the other end side (right end side in fig. 7), respectively, and engaged (engagement step). Thereby, the core 102 is held in a 22-sided shape (see fig. 6).

The operator joins the adjacent straight portions 102a by, for example, welding, as in the first embodiment. Thus, the wheel 100 is manufactured.

According to such a manufacturing method, the 22-sided (polygonal) core 102 (1 st wheel) can be easily manufactured by bending the core 102 (shaft member) extending in a straight line along the 21 (multiple) cutout portions 102b, respectively, and therefore, the manufacturing process can be simplified as compared with the case where the core 102 is bent in an arc shape.

Further, since the core 102 to which the free roller 110 (the 2 nd wheel) is attached is constituted by 1 continuous member, a decrease in rigidity can be suppressed as compared with a case where the core is constituted by connecting a plurality of members. Further, since the portion of the core 102 to which the free roller 110 is attached can be formed in a straight line (the straight line portion 102 a), the structure of the attachment portion (the bearing 104) of the free roller 110 can be simplified as compared with the case where the free roller 110 is attached to an arc-shaped portion.

Further, since the position of the bearing 104 (the free roller 110) can be fixed by bending the 1 st claw portion 102f1 and the 2 nd claw portion 102f2, respectively, it is not necessary to use a separate member for fixing the position of the bearing 104, and an increase in the number of members can be prevented.

Further, since the notch stress relaxation holes 102h are formed at both end portions in the circumferential direction of the notch 102b, when the linear portion 102a is bent by the notch 102b, the stress at the notch 102b is relaxed. This can prevent the core 102 from being broken due to stress concentration when bending the notch 102 b.

In the present embodiment, since the jig insertion hole is not formed in the straight portion 102a, the rigidity of the straight portion 102a can be improved as compared with the case where the jig insertion hole is formed.

Third embodiment

In the third embodiment shown in fig. 9 and 10, the wheel 200 has a polygonal core 202 (1 st wheel) (shaft member), and is used in an inverted pendulum type vehicle, an AGV, or the like, for example. The same reference numerals are given to the same constituent members as those of the first embodiment, and detailed description thereof is omitted.

In the present embodiment, for example, the core 202 is formed in a 32-sided shape, and divided into 32 straight portions 202a. Bearings 34 are attached to the respective straight portions of the 32 straight portions 202a, and free rollers 60 (2 nd wheels) are rotatably attached to the respective bearings 34.

As shown in fig. 9A to 9C, the core 202 is configured similarly to the core 32, and 31 cutouts 202b similar to the cutouts 32b of the core 32 are formed at a predetermined pitch.

The linear portion 202a has an outer surface 202c and an inner surface 202d, and a jig insertion hole 202e, a1 st claw portion 202f1, a 2 nd claw portion 202f2, a1 st notch 202g1, a 2 nd notch 202g2, a notch portion stress relaxation hole 202h, a claw portion stress relaxation hole 202i, an engagement protrusion 202j, and an engagement hole 202k are formed, similarly to the linear portion 32a of the first embodiment.

The 1 st claw portion 202f1 is formed at a position corresponding to the jig insertion hole 202 e. The 2 nd nail portion 202f2 protrudes rightward from the right side surface of the straight portion 202a in fig. 9A to 9C.

The 1 st notch 202g1 is formed continuously around 3 sides except 1 side on the outer side in the left-right direction among 4 sides of the claw portion 202a1 constituting the rectangular shape.

The 2 nd notch 202g2 is cut away from the left side surface of the linear portion 202a in the inward direction in fig. 9A to 9C. The 2 nd notch 202g2 is formed in a size that allows insertion of the 2 nd claw 202f2 of the adjacent straight portion 202a.

The engagement projection 202j includes a linear projection 202j1 and a circular arc projection 202j2, similar to the engagement projection 32j of the first embodiment. The engagement hole 202k includes a straight hole 202k1 and a circular hole 202k2, similar to the engagement hole 32k of the first embodiment.

[ manufacturing Process of wheel 200 ]

In manufacturing the wheel 200, as shown in fig. 10A, the operator first inserts the core 202 into the opening of the inner tube 34a of the bearing 34 to which the free roller 60 is rotatably attached in a state where the core 202 is formed in a straight line. For example, in the present embodiment, the bearing 34 (free roller 60) is provided at the straight portion 202a at the right end.

Next, as shown in fig. 10B, the operator inserts the jig JG into the jig insertion hole 202e provided with the straight portion 202a of the bearing 34, and bends the 1 st claw portion 202f1 downward along the 1 st notch 202 g. Then, the 1 st claw 202f1 bent downward is brought into contact with the right tapered portion 34d of the inner tube 34 a.

Next, the operator bends the 2 nd claw portion 202f2 of the right-end straight portion 202a. The 2 nd claw portion 202f2 bent at this time is used when the bearing 34 is fixed to the straight portion 202a at the left end, and thus bending is performed in advance.

Next, the operator bends the 2 nd claw portion 202f2 of the (2 nd from the right end) straight portion 202a on the side, and then bends the 2 nd straight portion 202a from the right end in the inward direction. By this bending process, the bent 2 nd claw portion 202f2 of the 2 nd straight portion 202a from the right end abuts against the tapered portion 34d on the left side of the inner tube 34 a.

Thereby, the bearing 34 provided on the right-end straight portion 202a is sandwiched between the 1 st bent claw portion 202f1 of the right-end straight portion 202a and the 2 nd bent claw portion 202f2 of the 2 nd straight portion 202a from the right end, and is fixed to the right-end straight portion 102a.

By performing the step of fixing the bearing 34 to the linear portion 202a (the disposing step, the bending step) on each of the 32 linear portions 202a, the bearing 34 is fixed to each of the 32 linear portions 302a in a state where the core 202 is formed in a 32-sided shape. In the present embodiment, the free roller 60 is rotatably mounted by performing the bending step after the disposing step. That is, the mounting step performed separately from the bending step is not provided.

In the present embodiment, for example, the bearing 34 provided on the 2 nd straight portion 202a from the right end is fixed by the 1 st bent claw portion 202f1 of the 2 nd straight portion 202a from the right end and the 2 nd bent claw portion 202f2 of the 3 rd straight portion 202a from the right end.

The bearing 34 provided on the left end straight portion 202a is fixed by the 1 st bent claw portion 202f1 of the left end straight portion 202a and the 2 nd bent claw portion 202f2 of the right end straight portion 202a.

When the operator forms the core 202 into a 32-sided shape, 2 engagement protrusions 202j formed on the straight portion 202a on one end side (left end side in fig. 9A to 9C) are inserted into 2 engagement holes 202k formed on the straight portion 202a on the other end side (right end side in fig. 9A to 9C), respectively, and engaged (engagement step). Thereby, the core 202 is held in the shape of a 32-sided polygon.

Further, the operator joins adjacent straight portions 202a to each other by welding, for example, as in the first embodiment. Thus, the wheel 200 is manufactured.

In the present embodiment, since only 1 jig insertion hole 202e is formed in the straight portion 202a, the rigidity of the straight portion 202a can be improved as compared with the case where 2 jig insertion holes are formed in the straight portion.

While the preferred embodiments of the present invention have been described above, as will be readily understood by those skilled in the art, the present invention is not limited to such embodiments, and may be modified as appropriate without departing from the spirit of the present invention.

For example, the number of the straight portions 32a, 102a, 202a may be changed as appropriate. The cross-sectional shape of the core 32, 102, 202 may be an elliptic cylinder or a polygonal cylinder.

In the first embodiment described above, the core 32 is folded into the 32-sided shape after the 32 bearings 34 (free rollers 60) are fixed to the 32 straight portions 32a, respectively, but the mounting step of mounting the bearings 34 to the straight portions 32a and the folding step of folding the core 32 at the cutout portions 32b may be alternately performed.

In addition, not all the constituent elements shown in the above embodiments are essential, and selection and replacement can be appropriately performed without departing from the gist of the present invention.

Claims (6)

1. A method for manufacturing a wheel comprising an annular 1 st wheel rotatable about a1 st axis and a plurality of 2 nd wheels arranged at predetermined intervals in an outer circumferential direction of the 1 st wheel, wherein the 2 nd wheels are rotatable about a 2 nd axis parallel to a tangent line tangent to an outer surface of the 1 st wheel,

the method for manufacturing a wheel is characterized by comprising the following steps:

a placement step of placing the 2 nd wheel on each of a plurality of straight line portions extending between adjacent cutout portions of the linear shaft member, the cutout portions being cut away in a direction orthogonal to the extending direction;

a bending step of bending the shaft member along the plurality of cutouts, respectively;

a joining step of joining the straight portions at both ends of the shaft member, which are respectively bent along the plurality of cutouts, to each other to form the 1 st wheel having a polygonal shape; and

a mounting step of mounting the 2 nd wheel to each of the plurality of straight portions so as to be rotatable about the 2 nd axis as a rotation center,

the wheel includes a plurality of bearings rotatably supporting a plurality of the 2 nd wheels,

in the mounting step, the 2 nd wheel rotatably supported by the bearing is rotatably mounted on the linear portion by bending a claw portion formed to be bendable on the shaft member, and bringing the claw portion into contact with the bearing to fix the bearing to the linear portion.

2. A method of manufacturing a wheel according to claim 1, wherein,

the claw portions are respectively provided on the respective straight portions of the plurality of straight portions,

when the straight portion is bent along the cutout portion, the claw portion abuts against the bearing.

3. A wheel, comprising:

a1 st wheel and a plurality of 2 nd wheels,

the 1 st wheel is a wheel in which a shaft member extending in a straight line and having a plurality of cutout portions formed at predetermined intervals is bent along the plurality of cutout portions, respectively, and both end portions of the shaft member are joined to each other to form a polygon, wherein the cutout portions have a shape cut away in an orthogonal direction orthogonal to the extending direction;

the plurality of 2 nd wheels are respectively mounted on a plurality of straight line parts of the 1 st wheel between the adjacent notch parts in a manner that the 2 nd wheels can rotate by taking a 2 nd axis parallel to a tangent line tangent to the outer surface of the 1 st wheel as a rotation center,

comprising a plurality of bearings rotatably supporting a plurality of the 2 nd wheels,

the shaft member is provided with a claw portion extending in the extending direction of the shaft member and bendable in the orthogonal direction,

the claw portion bent in the orthogonal direction abuts the bearing to fix the bearing to the straight portion, whereby the 2 nd wheel rotatably supported by the bearing is rotatably attached to the straight portion.

4. A wheel according to claim 3, wherein,

the claw portion is bent radially inward of the 1 st wheel in the orthogonal direction, whereby the bearing is fixed to the straight portion.

5. The wheel of claim 4, wherein the wheel is further configured to,

the claw parts are respectively arranged on a plurality of the straight line parts,

when the straight portion is bent along the cutout portion, the claw portion abuts against the bearing.

6. The wheel according to any one of claims 3 to 5, characterized in that,

a stress relaxation hole for relaxing stress at the bending portion when bending is performed at the notch portion is formed at an end portion of the notch portion in the cutting direction.

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