This invention relates to a clutch equipped with a friction plate mounted on a metallic support and having only a reduced deformation. The invention also relates to a clutch forming punch, and a method of manufacturing such clutch.
A clutch having an annular friction plate securely fixed on an annular metallic support is disclosed in a Patent Document 1 listed below. The friction plate disclosed in the Patent Document 1 is a member that comes into contact with a rotational drum to reduce its rotational speed when attracted onto the rotational drum. The friction plate is inserted in a space between the inner periphery and the outer periphery of the metallic support and is supported by the bottom of the metallic support. The friction plate is securely fixed on the metallic support with a multiplicity of swaging sections formed on the inner wall of the metal support so as touch the friction plate and with a multiplicity of swaging sections formed on the outer wall of the metallic support so as to touch the friction plate.
PATENT DOCUMENT 1: JPA4792051
Three swaging sections provided on an outer wall of a metallic support disclosed in the Patent Document 1 are formed in association with three paired swaging sections provided on an inner wall of the support. The swaging sections on the outer wall are formed at radially outward positions relative to, and in alignment with, their associated inner swaging sections.
An annular friction plate fixed at tight contact with the bottom of the support at the positions of paired swaging sections. However, portions of the friction plate remote from the paired swaging sections tend to come off (or separate from) the bottom of the metal support, so that the friction plate is likely to be corrugated in its circumferential direction as it is fixed on the bottom of the metal support. A large corrugated friction plate has a reduced area that comes into contact with the rotary drum, so that the braking power of the clutch is disadvantageously reduced.
In view of such a prior art problem as mentioned above, the present invention provides a clutch that is capable of retaining a friction plate flat to maintain its braking power. The invention also provides a punch for forming such clutch and a method of manufacturing such clutch.
There is provided in accordance with the present invention a clutch, as recited in claim 1, comprising
an annular metal support having
an annular bottom, a cylindrical inner wall perpendicular to the bottom, and a cylindrical outer wall coaxial with the inner wall and perpendicular to the bottom, the outer wall having a larger radius than the inner wall,
an annular friction plate arranged between, and in engagement with, the inner and the outer walls, and
a swaging structure for securely fixing the friction plate on the metal support by means of a first multiplicity of swaging sections provided at equal angular intervals in the circumferential direction of the inner wall to hold the friction plate on the bottom, and a second multiplicity of swaging sections provided at equal angular intervals in the circumferential direction of the outer wall to hold the friction plate on the bottom,
the clutch characterized in that the second multiplicity of swaging sections are offset from the first multiplicity of swaging sections in the circumferential direction of the metal support so as not to coincide with the first multiplicity of swaging sections with respect to any radial directions.
(Function) Since the positions of the second multiplicity of swaging sections are offset from those of the first multiplicity of swaging sections in the circumferential direction, if the first swaging sections pushing the inner periphery of the friction plate against the bottom of the metal support act to raise the outer periphery of the friction plate above the bottom of the metal support, the second swaging sections annihilate separation of the outer periphery by forcing the inner periphery of the upper face of the friction plate onto the bottom of the metal support. On the other hand, if the second swaging sections, pushing the outer periphery of the friction plate against the bottom of the metal support, act to raise the inner periphery of the friction plate above the bottom of the metal support, the first swaging sections will annihilate a rise of the inner periphery. In this way, the first and second swaging sections mutually annihilate such rises of the inner or the outer periphery of the friction plate, thereby reducing deformations of the friction plate in the circumferential direction, and retaining flatness of the friction plate on the metal support.
The clutch recited in Claim 1 may be configured as recited in Claim 2 such that
each of the first swaging sections has
each of the second swaging sections has
(Function) Since the first and second upper-end holders provided below the first and second sloping faces, respectively, and the first and second side holders together hold both the upper end and the side (both the inner and outer peripheries) of the friction plate in the neighborhood thereof, the friction plate is held in position with an enhanced holding force.
There is provided in accordance with the present invention as recited in Claim 3 a punch for forming the clutch according to either Claim 1 or 2, the punch comprising:
a body; and
a multiplicity of swaging claws each projecting perpendicularly from the body and arranged at positions spaced apart at equal angular intervals in association with either the first swaging sections or the second swaging sections,
wherein each of the swaging claws is tapered towards its tip end so that its length in the circumferential direction decreases in the direction towards the tip end.
Since swaging claws of a conventional punch are formed with parallelepiped protrusions and project from a body of the punch perpendicularly thereto, swaging holes formed during swaging at the leading ends of the inner wall and/or the outer wall of a metal support have rectangular inner walls perpendicular to the leading ends. A clutch equipped with a friction plate is subjected to a cutting operation in which a cutting tool is abutted against the leading ends of the outer and the inner walls of the metal support in rotation. Consequently, metallic burrs are generated inside the open ends of the parallelepiped swaging holes.
On the other hand, each of the swaging holes formed in the outer wall and the inner wall using an inventive punch in accordance with Claim 3 has a trapezoidal configuration having a sloping tapered inner face. This is due to the fact that each swaging claw of the punch is tapered towards it tip end such that the length of the claw in the circumferential direction decreases towards the tip end. In a case where the leading ends of the outer and inner walls of the metal support are cut with a cutting tool, the tapered sloping faces of the machined trapezoidal swaging holes of the outer and inner walls of the metal support are cut off by the cutting tool, leaving only negligibly small burrs inside the swaging holes, or in the best case leaving no burrs, as compared with cutting of conventional rectangular swaging holes.
The punch recited in Claim 3 may be configured as recited in Claim 4 such that each of the swaging claws has:
a perpendicular that extends from the body perpendicularly thereto; and
a sloping face in opposition to a circumferential end of the friction plate and inclined with respect to the perpendicular face and contiguous with a tip end of the perpendicular face.
(Function) The leading end of the inner wall or of the outer wall is deformed by the swaging claws pushing the end during swaging. Portions of deformed inner and outer walls are partly turned by the sloping faces of the claws in the direction towards the top end of the friction plate until the portions are all pushed onto the top end of the friction plate.
There is also provided in accordance with the present invention as recited in Claim 5, a method of manufacturing a clutch equipped with an annular friction plate securely fixed on a metal support which has:
the method comprising steps of:
the method characterized in that the second multiplicity of swaging sections are offset from the first multiplicity of swaging sections in the circumferential direction of the metal support so as not to coincide with the first multiplicity of swaging sections with respect to any radial directions.
It is noted that, since the second multiplicity of swaging sections are offset from the first multiplicity of swaging sections in the circumferential direction so as not to coincide with the latter swaging sections with respect to any radial directions, the first swaging sections force the inner periphery of the upper end of the friction plate against the bottom of the metal support if the outer periphery of the friction plate tends to rise above the bottom of the metal support, so that the second swaging sections, offset from the first swaging section in the circumferential direction, annihilate such rise of the friction plate. On the other hand, if the force of the second swaging sections pushing the outer periphery of the friction plate against the metal support tends to raise the inner periphery of the friction plate above the bottom of the metal support, the first swaging sections, offset relative to the second set of the swaging section in the circumferential direction, will annihilate such raise. In this way, the first and second swaging sections mutually annihilate the rise of the inner and the outer periphery of the friction plate to reduce a deformation of the friction plate that takes place in the circumferential direction, thereby retaining flatness of the friction plate on the metal support.
The method recited in claim 5 may be configured, as recited in claim 6, such that
the first multiplicity of swaging sections are formed on the inner wall of the metal support by means of a first punch which comprises:
the second multiplicity of swaging sections are formed on the outer wall of the metal support by means of a second punch which comprises:
(Function) The leading end of the inner wall or of the outer wall is deformed by the swaging claws of the first and second punches pushing the leading end. Portions of the deformed inner wall and the outer wall are partly turned from the inner and the outer peripheries of the friction plate by the sloping faces of the respective claws in the direction towards the top end of the friction plate until the portions are all pushed over the friction plate.
Since each of the swaging claws of the first punch and of the second punch is tapered towards its tip end such that the length of the claw in the circumferential direction decreases towards the tip end, each of the inner walls of the swaging holes of the first and second swaging sections formed by means of the first and second punches has a generally trapezoidal configuration which is tapered to its end. In a case where the leading ends of the outer and inner walls of the metal support are cut with a cutting tool, the tapered sloping faces of the machined trapezoidal swaging holes of the outer and inner walls of the metal support are partly cut off by a cutting tool. Consequently, burrs formed inside the swaging holes are reduced to negligibly small ones, or in the best case all the burrs are completely cut off.
The method recited in claim 6 may be configured, as recited in claim 7 such that
the first and second swaging sections are formed on the metal support by bringing the first punch and the second punches into contact with the inner and the outer walls, respectively, of the metal support, and that
the first and second punches are removed from the inner and the outer walls of the metal support while forcing the friction plate onto the bottom of the metal support by means of a biasing means.
It is noted that the first and second punches might be deformed after they cut into the inner and outer walls of the metal support, so that they might be difficult to be removed from the walls.
(Function) Since the first and second punches that have cut into the inner and outer walls are urged by a biasing force for liberation from the inner and outer walls, they can be more easily removed from the swaging sections of the inner (outer) wall.
The clutch recited in claim 1 ensures flatness of the friction plate fixed on the clutch, thereby allowing the clutch to maintain good braking performance.
In the clutch recited in claim 2, the friction plate is firmly fixed on the metal support with the first and second swaging sections that firmly hold the upper end, outer circumference, and inner circumference on the metal support.
Unlike a conventional punch, the inventive punch recited in Claim 3 requires no de-burring operation after machining the upper ends of the inner and outer walls of the metal support, since the punch leaves negligibly little or no burrs in the swaging sections.
The punch recited in Claim 4 can prevent generation of a burr by controlling the directions of those metal portions of the inner or outer periphery of the metal support in such a way that the portions are deformed by the claws to heap on top of the upper end of the friction plate. As a result, the friction plate is still more securely fixed on the metal support by enhanced holding power of the swaging sections.
Since the friction plate held on the metal support is maintained flatter than ever before by the method as recited in Claim 5, the method enables production of a clutch having a sustainable braking performance.
In the method of manufacturing a clutch as recited in Claim 6, portions of the inner and outer peripheries of the metal support to be deformed by the first and second swaging claws are deformed effectively, without creating a burr, by the sloping faces of the claws so as to heap up over the upper end of the friction plate, thereby facilitating firm fixation of the friction plate on the metal support. Furthermore, those burrs formed during the formation of the first and second swaging sections are either negligibly small or largely removed, so that no de-burring operations is necessary.
The method of manufacturing a clutch as recited in Claim 7 has a much less work that needs to stop the manufacturing line to remove the first and/or the second punch cutting in the inner and outer walls of the metal support. Accordingly, the method has an improved manufacturing efficiency.
FIG. 3A(a) is an enlarged cross section of a first swaging section 12 shown in
a) is a cross section of the metal support, taken along a circumferential line II-II in
a) is a perspective view of a first punch,
a) is a perspective view of a second punch,
a) illustrates a process of machining upper ends of the inner and outer walls of the metal support.
a) illustrates a burr formed near a trapezoidal swaging hole of an inventive metal support.
The inventive clutch will now be described in detail with reference to a first embodiment as shown in
A clutch 1 shown in
The friction plate 3 shown in
As shown in
The first punch 10 comprises a disk shape first body 14, a cylindrical rib 15, and a first multiplicity of swaging claws 16 as shown in
As shown in
It is noted that each of the first swaging claws 16 has a vertical face 16a, which is contiguous with the inner periphery 15a of the rib 15, and a sloping face 16b inclined from the tip 16c of the vertical face 16a at an acute angle, as shown in
As shown in
Each of the second swaging claws 19 shown in
It is also noted that each of the second swaging claws 19 is configured to have an acute-angled apex consisting of a vertical face 19a and a sloping face 19b such that the vertical face 19a is contiguous with the outer periphery 18a of the rib 18 and perpendicular to the upper end 17b of the second body 17 while the sloping face 19b is contiguous with the tip end 19c of the vertical face 19a. The sloping face 19b is inclined upward from the inner periphery 17a of the second body 17 and extends radially outwardly (in the direction of an arrow OU) towards the tip end 19c of the vertical face 19a.
As an example, the first punch 10 is provided with nine first swaging claws 16 on the rib 15 as shown in
The first swaging sections 12 of the metal support 2 (shown in
Each of the first swaging sections 12 shown in FIG. 3A(a) is formed of; an upward sloping face 12a extending in a radially inward direction (as indicated by an arrow IN) and towards above the frictional plate 3; a first upper-end holder 12b for holding the upper end 3d of the friction plate 3 near its inner periphery 3a; and a first side holder 12c for holding the inner periphery 3a of the friction plate 3. The upward sloping face 12a is contiguous at its lower end 12e with the lower end 12e of a vertical face 12d which is formed at a radially inward position recessed from the outer periphery of the inner wall 5. The lower end 12e is lateral to the inner periphery 3a. Each of the second swaging sections 13 is formed of; a second sloping face 13a that extends from the outer wall 6 radially inwardly and towards above the friction plate 3; a second upper-end holder 13b, near the outer periphery 3b, for holding the upper end 3d of the body 8 of the friction plate 3; and a second side holder 13c for holding the outer periphery 3b of the friction plate 3. The second sloping face 13a is contiguous at its lowest end with the lower end 13e of a vertical face 13d which is formed at a radially outward position recessed from the inner periphery of the outer wall 6. The lower end 13e is lateral to the outer periphery 3b of the friction plate 3.
The first upper-end holder 12b of the first swaging section 12 is adapted to hold the upper end 3d of the body 8 of the friction plate 3. To do so, the first upper-end holder 12b is located radially inward with respect to a normal O2 to the upward sloping face 12a passing through the upper end 3e of the inner periphery 3a of the friction plate 3. The first side holder 12c is adapted to hold the inner periphery 3a of the friction plate 3. To do so, the first side holder 12c is located radially inwardly in the first swaging sections 12 with respect to the normal O2. On the other hand, the second swaging sections 13 are adapted to hold the upper end 3d of the friction plate 3 close to the outer wall 6. To do so, each of the second swaging sections 13 is located radially inwardly in the second swaging section 13 with respect to a normal to the second sloping face 13a passing through the upper end 3f of the outer periphery 3b of the friction plate 3. The second side holder 13c of the second swaging section 13 is adapted to hold the outer periphery 3b of the friction plate 3. To do so, the second side holder 13c is located radially outward with respect to a normal O3. Thus, the first and second swaging sections 12 and 13, respectively, together securely hold the friction plate 3 by holding the upper end 3d, inner periphery 3a, and outer periphery 3b of the body 8 of the friction plate 3. The first swaging sections 12 and the second swaging sections 13 collaborate to constitute a swaging structure 37.
Referring to
As show in
As shown in
As the pressurizer 27 shown in
On the other hand, in a process of forming the first and second swaging sections as shown in
As shown in
After the pressurizer 27 is raised, there remain first swaging holes 30 and second swaging holes 31 in the inner wall 5 and the outer wall 6, respectively, of the metal support 2 formed by the respective first and second swaging claws 16 and 19 inserted as shown in
Referring to
b) shows the clutch 1 as viewed in the radially inward direction indicated by an arrow V3 when the clutch 1 is in operation for cutting its upper ends (5a and 6a).
a) and (b) shows that the inventive clutch 1 is removed of marginal portions S1 of the upper end 5a of the inner wall 5 and the upper end 6a of the outer wall 6 by the cutting part 34 of the cutting tool 33. On the other hand, the clutch 41 shown in
Upon comparison of the marginal portion S1 shown in
On the other hand, in the case of the clutch 41 shown in
Consequently, as shown in
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/JP2013/059572 | 3/29/2013 | WO | 00 |