Rotary shafts – gudgeons – housings – and flexible couplings for ro – Torque transmitted via flexible element – Coil spring
Reexamination Certificate
2002-01-11
2004-03-30
Binda, Greg (Department: 3679)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Torque transmitted via flexible element
Coil spring
C192S205000
Reexamination Certificate
active
06712705
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention generally relates to a damper mechanism. More specifically, the present invention relates to a damper mechanism that uses a coil spring assembly.
2. Background Information
A conventional damper mechanism used in a clutch disk assembly of a vehicle has an input rotating member, an output rotating member, and an elastic coupling member. The input rotating member can be coupled to an input flywheel. The output rotating member is coupled to a shaft that extends from the transmission. The elastic coupling member elastically couples the input rotating member and the output rotating member in a rotational direction. The input rotating member has a clutch disk and a pair of input plates fixed to the inside thereof. The output rotating member has a hub that is coupled to the shaft such that the two cannot rotate relative to each other. The hub has a boss that is splined to the shaft and a flange that extends radially outward from the boss. The elastic coupling mechanism has a plurality of large, high-rigidity coil springs. Each coil spring is housed inside a window formed in the flange and furthermore is supported by windows formed in the pair of input plates. When the pair of input plates and the hub rotate relative to each other, the coil springs are compressed between the two members in the rotational direction. This damping function serves to absorb and damp rotational-direction torsional vibrations inputted to the clutch disk assembly.
A separated-flange type clutch disk assembly is also known. In the separated-flange type clutch disk assembly, the flange is independent from the hub and the flange and hub are coupled in the rotational direction by small, low-rigidity coil springs. With this type of clutch disk assembly, the small coil springs are compressed when in a region of small torsional angles and low-rigidity characteristics are obtained. Further, when in the region of large torsional angles, the large coil springs are compressed and high large-rigidity characteristics are obtained.
When the coil springs are compressed in the rotational direction, the deflection of the side of the coil springs that is farther from the center axis of the clutch disk assembly is larger than that on the side closer to the center axis. This is because the portion of the windows (which push the coil springs) farther from the center axis moves a larger distance in the rotational direction than does the portion closer to the center axis. As a result, the amount the inside wire twists to absorb the deflection of the part that is farther from the center axis is larger than the amount the outside wire twists. The stress on the inside wire is also larger. Thus, the stress generated on a single coil spring is not uniformly distributed and the life of the entire coil spring is shortened.
Also, the structure of conventional clutch disk assemblies is such that 3 to 12 springs are disposed in spring supporting parts provided at 3 to 6 locations positioned to the outside from the center axis in the radial direction. Consequently it is desirable to simplify the structure of the damper mechanism by reducing the number of coil spring assemblies. In particular, since the coil spring assemblies are disposed farther from the center axis of the clutch disk assembly than are the small coil springs, it is preferred to reduce the number of coil spring assemblies and enlarge the small coil springs so that designing can be simplified.
However, since the durability of the aforementioned coil springs is not sufficient, it is considered difficult to increase the torque capacity of the coil springs and reduce the number of coil spring assemblies.
In view of the above, there exists a need for a damper mechanism that overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.
SUMMARY OF THE INVENTION
An object of the present invention is to simplify the structure of the damper mechanism while maintaining the same torsional characteristics as conventional damper mechanisms.
A damper mechanism in accordance with a first aspect of the present invention has an input rotating body, an output rotating body, and two or more coil spring assemblies. The two or more coil spring assemblies elastically couple the input rotating body and the output rotating body together in a rotational direction and serve to absorb twisting torque. Each of the coil spring assemblies has at least one coil spring whose center axis is roughly linear. At least one of the coil spring assemblies absorbs 35% to 50% of the twisting torque.
In this damper mechanism, at least one of the two or more coil spring assemblies absorbs 35% or more of the twisting torque of the damper mechanism. Consequently, the number of coil spring assemblies can be reduced and the structure of the damper mechanism can be simplified while maintaining the same torsional characteristics as conventional damper mechanisms.
A damper mechanism in accordance with a second aspect of the present invention is the damper mechanism of the first aspect, wherein the coil springs are mounted such that the number of active coils on the side that is closer to the center axis of the damper mechanism is larger than the number of active coils on the side that is farther from the center axis of the damper mechanism.
This damper mechanism makes it possible to reduce the difference in per-coil deflection between the farther side and the closer side of the springs when the springs are compressed. In other words, the difference between the stress generated in the portion of each coil that is farther from the center axis and the stress generated in the portion of each coil that is closer to the center axis is reduced. As a result, the strength of the coil spring is improved and its torque capacity can be increased.
A damper mechanism in accordance with a third aspect of the present invention is the damper mechanism of the first or second aspect wherein the two or more coil spring assemblies have one pair of coil spring assemblies disposed in positions that are opposed in the radial direction. The pair of coil spring assemblies absorbs 70% to 100% of the twisting torque.
With this damper mechanism, the pair of coil spring assemblies absorbs 70% or more of the twisting torque of the damper mechanism. Therefore, the number of coil spring assemblies can be reduced and the structure of the damper mechanism can be simplified while maintaining the same torsional characteristics as conventional damper mechanisms.
A damper mechanism in accordance with a fourth aspect of the present invention has an input rotating body, an output rotating body, and two or more coil spring assemblies. The two or more coil spring assemblies couple the input rotating body and the output rotating body together elastically in the rotational direction, and serve to absorb twisting torque. Each of the coil spring assemblies has at least one coil spring whose center axis is roughly linear. The angle formed by two radii passing from the center axis of the damper mechanism through the ends of the coil spring is in the range of 60 to 140 degrees.
In this damper mechanism, the coil springs that extend linearly are larger than conventional coil spring because the angle thereof is 60 degrees or greater. Consequently, the number of coil springs can be reduced and the structure of the damper mechanism can be simplified while maintaining the same torsional characteristics as conventional damper mechanisms.
A damper mechanism in accordance with a fifth aspect of the present invention is the damper mechanism of the fourth aspect, wherein the aforementioned angle is in the range of 60 to 120 degrees.
In this damper mechanism, more space can be secured between the coil springs in the circumferential direction because the angle formed by two radii passing from the center axis of the damper mechanism through the ends of the coil spring(s) does
Fujita Yasuhiko
Uehara Hiroshi
Exedy Corporation
Shinjyu Global IP Counselors, LLP
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