Rotary shafts – gudgeons – housings – and flexible couplings for ro – Torque transmitted via flexible element – Coil spring
Reexamination Certificate
1998-10-28
2001-08-14
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Torque transmitted via flexible element
Coil spring
C464S007000, C464S024000
Reexamination Certificate
active
06273823
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns a torsional vibration damper with two components that rotate in relation to each other, and a spring chamber. In this spring chamber is usually at least one spring that acts tangentially between the two components, e.g. a spiral spring.
In the following, axial means a direction parallel to the main rotational axis of the torsional vibration damper, radial means a direction away from the main rotational axis in a plane perpendicular to the main rotational axis of the torsional vibration damper, and tangential means perpendicular to the two cited directions.
SUMMARY OF THE INVENTION
The problem of this invention is to present a generic torsional vibration damper where the spring chamber is sealed against the exit of lubricant, etc. such as grease.
As a solution, the invention suggests a generic torsional vibration damper where the first module has a first guide surface and seals the spring chamber radially outward, whereby the first guide surface is at a distance from the second module across a gap and is essentially radial, and an essentially radial second guide surface is provided that covers the gap (
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) on the spring chamber side.
The invention is based on the idea that grease flows everywhere in the spring chamber, and when it contacts a wall, it experiences a centrifugal force that moves it radially outward. Grease that contacts guide surfaces is hence radially accelerated. Given the radial guide surfaces facing the spring chamber, the grease on a guide surface will be transported radially outward along the surface due to centrifugal force.
The second guide surface guarantees that grease splashing everywhere cannot pass through the gap between the first guide surface and second module since it is first captured by the second guide surface. Since the second guide surface is situated faces the spring chamber in regard to the gap and hence in regard to at least one area of the first guide surface, grease that leaves the second guide surface radially outward is at least captured by the first guide surface. The centrifugal force prevents this grease from accelerating radially inward toward the gap between the first guide surface and second guide surface.
Because of the gap between the first guide surface and second module, the spring chamber can be sealed without contact in the present invention. This arrangement accordingly does not advantageously influence the other properties of the torsional vibration damper, especially when it used for clutches.
The first guide surface can be a baffle that is fixed to the first module. Compared to the single-piece design of the first module and first guide surface, this arrangement is easier to manufacture. In particular, difficult undercuts can be avoided. Any type of suitable fastener can be used to connect the baffle and first module such as soldering, welding, rivets, etc.
It is easier to manufacture a torsional vibration damper according to the invention especially when the connection between the first module and the baffle is a clip connection. For example, the baffle can be bent as a clamp that opens easily due to the intrinsic elasticity of the material and grasps a projection of the first module.
In particular, the baffle can be in the shape of a washer. Usually, a generic torsional vibration damper has several tangential springs or spring chambers. With such an annular arrangement, the annular design of the baffle is particularly easy to mount since a corresponding baffle can be mounted in a single step for all spring chambers. Given the radial symmetry of this design, it is easy to design a clamp to connect the baffle with the first module.
In addition, the second guide surface can be designed as a guide disk. Such a guide disk can be easily placed over the gap between the first guide surface and second module on the spring chamber side. In particular, it is advantageous for the cited reasons to design the guide disk serving as a second guide surface in the shape of a washer.
The guide disk can be fixed to the first guide surface or the baffle. This fixed connection can e.g. be created by a clip connection, a rivet connection or a torx rivet connection. This fixed connection increases the stability of the unit formed by the disk and first guide surface or baffle. In particular, it is possible to create the guide disk out of a light and low-friction material such as plastic since the first guide surface or baffle serves to stabilize the guide disk. This arrangement also allows the guide disk and baffle to be premounted which makes it easier to manufacture a torsional vibration damper according to the invention.
There can be at least one opening facing the spring chamber between the first guide surface and second guide surface. Lubricant or grease can be returned to the spring chamber through this opening that has somehow reached behind the second guide surface, e.g. by creep. In particular, it is advantageous when the opening is situated so radially moving particles can pass through. In this case, particles behind the second guide surface are returned to the spring chamber.
There can be a calm space between the first and second guide surface close to the gap between the first guide surface and second module. Lubricant can collect in this area that has reached behind the second guide surface and is thus prevented from passing through the gap. Such a calm space is particularly advantageous when there is a corresponding opening in the radial exterior of the area through which the collected grease can return to the spring chamber.
Between the first and second guide surface, there can be an element (preferably a ring) made of absorbent material that covers the gap between the first guide surface and the second module, at least when the torsional vibration damper is still. Such an absorbent material can be any kind of material that can absorb and release the lubricant, etc. in the spring chamber. In particular, this material can be a felt-like sponge or foam. The material should have a greater capillary force than the gap. When this absorbent material covers the gap between the first guide surface and second module, grease, etc. is prevented from creeping through the gap. When the torsional vibration damper rotates, such creep is insignificant due to the centrifugal force. Hence this sealing ring can be designed so that, upon rotation, it raises from the second module or first guide surface due to centrifugal force to provide a contactless seal when the torsional vibration damper rotates. In particular, this seal can be in a calm space between the first and second guide surfaces.
In addition, it is advantageous when radial, external openings are provided between the first guide surface and second guide surface to the spring chamber. Lubricant collected in the sealing ring is transported by centrifugal force into the spring chamber.
It is especially possible to premount an arrangement consisting of the sealing ring, baffle and guide disk. For example, the baffle and guide disk can be fixed together as described above so that the sealing ring is suitably fixed between the guide disk and baffle.
The sealing ring can be held under radial, inward pretension of a guide disk comprising one of the two guide surfaces. The guide disk can be designed so that the pretension is preferably reduced to zero when the torsional vibration damper rotates. The guide disk can e.g. have axial projections that grip the sealing ring and press radially inward against the second module. The axial projections are dimensioned so that they move outward under centrifugal force when the torsional vibration damper rotates and hence release the sealing ring.
The second module of the torsional vibration damper according to the invention can be a third, essentially radial guide surface that covers an axial gap between the second guide surface and the second module on the side facing away from the spring chamber. Lubricant particles that may pass through a possibly existing axially-open gap between the second guide sur
Heidingsfeld Dietmar
Rohs Hans
Rohs Ulrich
Browne Lynne H.
Dunwoody Aaron M
Feiereisen Henry M.
Rohs-Voigt Patentverwertungs-gesellschaft mbH
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