ROTATING MEMBER AND FORMING METHOD THEREOF

Abstract

To provide a rotating member and a forming method thereof that allow formation of protrusions biting into an opposite surface to achieve high slip torque with a simple configuration. The rotating member includes a boss part and an anti-slip surface at least on one of both axial end faces of the boss part. The anti-slip surface has a plurality of corrugated rib parts, which includes a main groove and at least one auxiliary groove extending parallel to the main groove, with a ridge protruding higher than the anti-slip surface between the main groove and the auxiliary groove.

Claims

1. A rotating member comprising a boss part and an anti-slip surface at least on one of both axial end faces of the boss part, the anti-slip surface having a plurality of corrugated rib parts, the corrugated rib parts including a main groove and at least one auxiliary groove extending parallel to the main groove, with a ridge protruding higher than the anti-slip surface between the main groove and the auxiliary groove.

2. The rotating member according to claim 1, wherein the corrugated rib parts have the auxiliary groove on both sides of the main groove.

3. The rotating member according to claim 1, wherein the ridge has a tapered side face on a side facing the main groove, and a tapered side face on a side facing the auxiliary groove.

4. The rotating member according to claim 3, wherein a side face of the ridge on a side facing the main groove and a side face of the ridge on a side facing the auxiliary groove make an angle of 30° to 60°.

5. The rotating member according to claim 1, wherein some or all of the plurality of corrugated rib parts are formed to extend radially on the anti-slip surface.

6. The rotating member according to claim 1, wherein some or all of the plurality of corrugated rib parts are formed to extend helically on the anti-slip surface.

7. A method of forming a rotating member having a boss part and an anti-slip surface at least on one of both axial end faces of the boss part, the method comprising a step of forming a plurality of corrugated rib parts on the anti-slip surface, wherein a main groove and at least one auxiliary groove extending parallel to the main groove are formed by forging to obtain a ridge protruding higher than the anti-slip surface between the main groove and the auxiliary groove in the corrugated rib parts.

8. The method of forming a rotating member according to claim 7, wherein the corrugated rib parts are formed to have the auxiliary groove on both sides of the main groove.

9. The method of forming a rotating member according to claim 7, wherein the corrugated rib parts are formed such that the ridge has a tapered side face on a side facing the main groove, and a tapered side face on a side facing the auxiliary groove.

10. The method of forming a rotating member according to claim 9, wherein the corrugated rib parts are formed such that a side face of the ridge on a side facing the main groove and a side face of the ridge on a side facing the auxiliary groove make an angle of 30° to 60°.

11. The method of forming a rotating member according to claim 7, wherein some or all of the plurality of corrugated rib parts are formed to extend radially on the anti-slip surface.

12. The method of forming a rotating member according to claim 7, wherein some or all of the plurality of corrugated rib parts are formed to extend helically on the anti-slip surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1A is a reference front view of a rotating member (sprocket) having an anti-slip surface;

[0023] FIG. 1B is a reference side view of a rotating member (sprocket) having an anti-slip surface;

[0024] FIG. 2 is a (partial) front view of a rotating member according to a first embodiment of the present invention;

[0025] FIG. 3 is a cross section along the line A-A of FIG. 2; and

[0026] FIG. 4 is a (partial) front view of a rotating member according to a second embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] A rotating member according to the present invention includes a boss part and an anti-slip surface at least on one of both axial end faces of the boss part, the anti-slip surface having a plurality of corrugated rib parts. The corrugated rib parts include a main groove and at least one auxiliary groove extending parallel to the main groove, with a ridge protruding higher than the anti-slip surface between the main groove and the auxiliary groove. A method of forming an anti-slip feature of a rotating member according to the present invention is a method of forming a rotating member having a boss part and an anti-slip surface at least on one of both axial end faces of the boss part, and includes a step of forming a plurality of corrugated rib parts on the anti-slip surface. A main groove and at least one auxiliary groove extending parallel to the main groove are formed by forging to obtain a ridge protruding higher than the anti-slip surface between the main groove and the auxiliary groove in the corrugated rib parts. The invention may have any specific configurations as long as it provides a rotating member and a forming method thereof that allow formation of protrusions biting into an opposite surface to achieve high slip torque with a simple configuration.

Embodiment 1

[0028] A sprocket 100 that is a rotating member according to a first embodiment of the present invention has a plurality of teeth 102 formed along the outer circumference, as illustrated in FIG. 2. When the sprocket is secured to a crankshaft (not shown), a boss part 101 is inserted into an end portion of the crankshaft, and the sprocket is axially fastened with a bolt or the like, so that an anti-slip surface 111 formed on an end face 103 of the boss part 101 abuts on the crankshaft to transmit torque.

[0029] The anti-slip surface ill includes a plurality of corrugated rib parts 120, which are regularly spaced apart such as to extend radially entirely over the anti-slip surface 111.

[0030] The corrugated rib part 120 includes, as illustrated in FIG. 3, a main groove 125 extending along one direction and having an inverted chevron cross section, auxiliary grooves 127 extending on both sides of this main groove 125 parallel thereto and spaced therefrom and having an inverted chevron cross section, and two ridges 123 protruding higher than the anti-slip surface 111 between the main groove 125 and the adjacent one of the auxiliary grooves 127. The ridge 123 stands upright from the anti-slip surface 111 and has a chevron cross section with a pointed tip, or a shape that makes the shear stress applied to the ridge 123 biting into an opposite surface (an end face of the crankshaft to which the sprocket is fastened) equal to or lower than the allowable stress of the material.

[0031] The side faces 123a facing the main groove 125, and side faces 123b facing the auxiliary grooves 127, of the ridges 123, are each a tapered surface. The angle θ between the side faces 123a facing the main groove 125 and side faces 123b facing the auxiliary grooves 127 of the ridges 123 are from 30° to 60°, for example.

[0032] The main groove 125 has a depth d1 from the anti-slip surface 111 of, for example, 0.4 to 1.0 mm.

[0033] The auxiliary grooves 127 have a smaller depth d2 from the anti-slip surface 111 than the depth d1 from the anti-slip surface 111 of the main groove 125, which is, for example, 0.1 to 0.7 mm.

[0034] The ridges 123 have a height t from the anti-slip surface 111 of, for example, 0.1 to 0.8 mm.

[0035] In this embodiment, the corrugated rib parts 120 are formed by stamping the main groove 125 and auxiliary grooves 127 extending on both sides of the main groove 125 parallel thereto and spaced therefrom using a forging (pressing) technique, whereby excess material produced as a result of groove formation rise and form protrusions (ridges 123) that protrude higher than the anti-slip surface 111 between the main groove 125 and the auxiliary grooves 127.

[0036] The main groove 125 and auxiliary grooves 127 may be stamped at the same time, or the auxiliary grooves 127 may be stamped after the main groove 125 has been stamped, or the main groove 125 may be stamped after the auxiliary grooves 127 have been stamped.

Embodiment 2

[0037] The sprocket that is a rotating member according to a second embodiment of the present invention has a plurality of corrugated rib parts 120 regularly formed such as to extend helically as illustrated in FIG. 4. Other configurations are similar to those of the first embodiment.

[0038] While the embodiments described above each envisage the corrugated rib parts being provided uniformly all around, the corrugated rib parts may be formed with different densities and directions in different parts, or may be changed continuously, or may include different forms of embodiments mixed together, or may be formed to intersect each other.

[0039] The corrugated rib parts are not limited to those with auxiliary grooves on both sides of the main groove to have two ridges. One ridge, with one auxiliary groove on one side of at least one main groove, may suffice.

[0040] While the main groove and auxiliary grooves of the corrugated rib parts are illustrated as being grooves with an inverted chevron cross section, they may be formed as grooves with an inverted semicircular cross section, as long as the shape ensures reliable biting of the ridges formed between the main groove and the auxiliary grooves into the end face of the crankshaft.

[0041] For stamping the main groove and auxiliary grooves, any types of devices may be used as long as a main groove and auxiliary grooves of desired shapes can be stamped.

[0042] The sprocket illustrated as a rotating member is only an example. The invention is applicable to any rotating member that receives torque from an end face and thus can be used in various industrial fields.