Patent Application
20080036128
Referring now to the attached drawings which form a part of this original disclosure:
Selected embodiments of the present invention will now be explained with reference to the drawings. It will be apparent to those skilled in the art from this disclosure that the following descriptions of the embodiments of the present invention are provided for illustration only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. Embodiments of a spring assembly 5 being adapted in the present invention will be explained hereinafter with reference to the attached drawings.
A dual mass flywheel 1 includes a spring assembly 5, which has been adapted to an embodiment of the present invention shown in
Line O-O line in
Referring to
The flexible plate 11 is a member which transmits torque from the crankshaft 91 to the inertia member 13, while absorbing torsional vibration from the crankshaft 91. The flexible plate 11 is made to have a high stiffness in a rotating direction and a low stiffness in an axial and torsional direction. The flexible plate 11 is formed in a disc shape having a central hole. The flexible plate 11 is preferably made from sheet metal. A circular flange of the flexible plate 11 is fixed to the end of the crankshaft 91 by a plurality of bolts 22. The flexible plate 11 has corresponding through-holes for the bolts 22. The bolts 22 are preferably fixed to the crankshaft 91 from the axial direction transmission side.
The inertia member 13 is made from a thick block-like member and is being fixed at an outer periphery portion of the flexible plate 11 at an axial transmission side by rivets (not shown). An engine starter ring gear 14 is fixed at an outer periphery of the inertial member 13. Further, the first flywheel 2 may be formed by an integrally structured member.
The second flywheel 3 is an annularly shaped disc-like member, and is provided at the axial transmission side of the first flywheel 2. Further, the second flywheel 3 includes a flywheel body 3A and a positioning member 3B, which radially positions the flywheel body 3A relative to a member arranged at the side of the crankshaft.
The flywheel body 3A is a member shaped in an annular form. The thickness in the axial direction of the flywheel body 3A is preferably thicker than the thickness of the flexible plate 11. An annular and flat clutch friction surface 3a is formed on the axial transmission side. The clutch friction surface 3a is a portion where a clutch disc assembly (not shown) is connected.
The positioning member 3B is a member shaped in an annular form, preferably made of sheet metal plate. The positioning member 3B is provided at the inner periphery of the flywheel body 3A. The positioning member 3B includes an outer periphery 67, which contacts with the inner periphery of flywheel body 3A so that the positioning member 3B and the flywheel body 3A are constructed to have a concentric structure. The positioning member 3B includes a cylindrical portion 70, which further extends toward the axial engine side at an inner periphery thereof.
The damper mechanism 4 will be explained hereinafter. The damper mechanism 4 elastically engages the crankshaft 91 and the second flywheel 3 in the rotation direction. The second flywheel 3 is engaged to the crankshaft 91 through the damper mechanism 4, and thus constructs a flywheel assembly together with the damper mechanism 4. The damper mechanism 4 includes a pair of output disc plates 32 and 33, an input disc plate 20, a spring assembly 5, and a third coil spring 36.
The pair of output disc plates 32 and 33 includes a first plate 32 that is provided at an axial engine side, and a second plate 33 that is provided at the axial transmission side. Both plates 32 and 33 are disc-shaped members, which are positioned having predetermined gaps with each other in the axial direction at different inner radial positions. Circumferentially arranged plural window portions 46 are formed on each plate 32 and 33. The window portion 46 is configured to support the spring assembly 5 (described thereinafter) in an axial direction and rotating direction. The window portion 46 includes a stand-up portion, which supports the spring assembly 5 in the axial direction and contacts with both circumferential ends thereof. The window portion 46 is arranged at four circumferential positions. Further, a couple of second window portions 48 are provided at each plate 32 and 33 where the second window positions 48 are arranged at opposite positions from each other relative to the center of the each plate 32 and 33. The second window portions 48 are provided at an outer periphery of the window portions 46. The second window portions 48 support the third coil spring 36 (described hereinafter) in the axial direction and in the rotating direction.
Both outer peripheries of the first plate 32 and the second plate 33 are firmly fixed together by a plurality of rivets 41 and 42 in proximity to each other while maintaining predetermined distances between the inner peripheries of the first plate 32 and the second plate 33 in an axial direction. The first rivets 41 are circumferentially arranged. The second rivets 42 secure connecting stand-up portions 43 and 44, which are respectively formed on the first plate 32 and the second plate 33. The connecting stand-up portions 43 and 44 are provided at two respective positions, radially facing each other, more particularly, the connecting stand-up positions 43 and 44 are provided at radially outside positions of the window portions 46.
The input disc plate 20 is shaped in the form of a disc, and is provided between the output disc plates 32 and 33. Window openings 38 are formed on the input disc plate 32. The window openings 38 provided at the input disc plate 20 correspond with the window portions 46. Each window opening 38 provided at the input disc plate has a relatively linear window frame at a radially inner side. The each linear frame preferably has a notch 38a, which recesses at each center portion thereof in a rotating direction. Further, a recessed portion 38b is formed at both ends in a rotating direction of the window openings 38 provided at the input disc plate. Referring now to
The input disc plate 20 is fixed to the crankshaft 91 by the bolts 22, together with the flexible plate 11 and a supporting member 19. The inner periphery of the flexible plate 11 is in contact with an end surface 91 a of the crankshaft 91, on near side of a transmission in the axial direction. The supporting member 19 includes a cylindrical portion 19a and a disc-like portion 19b which extends from an outer periphery of the cylindrical portion 19a in a radial direction. The disc-like portion 19b is in contact with an end surface of the flexible plate 11 on a transmission side in the axial direction. The inner periphery of the cylindrical portion 19a is in contact with an outer peripheral surface of a columnar projection 91b which is formed at the center of an end portion of the crankshaft 91, so as to be concentric with the crankshaft. The inner periphery of the flexible plate 11 is in contact with an outer peripheral surface of the cylindrical portion 19a at an axial engine side in the axial direction so that the flexible plate 11 and the cylindrical portion 19 are constructed in a concentric manner. The inner periphery of the input disc plate 20 is in contact with an outer peripheral surface of the base portion of the cylindrical portion 19a at the transmission side in the axial direction so that the input disc plate 20 and the cylindrical portion 19a are constructed in a concentric manner. A bearing 23 is provided at the inner surface of the cylindrical portion 19a in order to support rotatably an end portion of an input shaft of the transmission. Further, the flexible plate 11, the supporting member 19, and the input disc plate 20 are firmly fixed by screws 21.
An outer periphery of the cylindrical portion 19a of the supporting member 19 supports an inner periphery of the cylindrical portion 70 of the positioning member 3B through a bush 30. Due to the aforementioned construction, the positioning member 3B is defined to be concentric with the first flywheel 2 and the crankshaft 91 by the supporting member 19. Further, the flywheel body 3A is defined concentric with the first flywheel 2 and the crankshaft 91 via the positioning member 3B. The bush 30 includes a column portion 30a, which is positioned between the cylindrical portion 70 and the cylindrical portion 19a, and a thrust portion 30b, which is positioned between the inner periphery of the input disc plate 20 and an end portion of the cylindrical portion 70 of the positioning member 3B. Due to the aforementioned construction, the thrust load of the second flywheel 3 is received by each member arranged in line with the axial direction such as the flexible plate 11, the supporting member 19, and the input disc plate 20 through the thrust portion 30b.
Spring assemblies 5 are provided in the plurality of window portions 46. Referring to
Both ends of the large coil spring 34 extend to both ends of the window portion 46 in a rotating direction and to the window opening 38 provided in the input disc plate 20.
The small coil spring 35 is positioned within the large coil spring 34. Further, the small coil spring 35 is formed to have a moderate arc shape that extends in a radially outward direction relative to the dual mass flywheel 1. The arc is configured so that both ends of the small coil spring 35 are in contact with an inner surface of the large coil spring 34 at an inner side in a radial direction of the large coil spring 34 and the small coil spring 35, while the center portion of the small coil spring 35 is in contact with an inner surface of the center portion of the large coil spring 34 at the radially outward sides of the large coil spring 34 and the small coil spring 35 in an uncompressed state, i.e., when the springs 34 and 35 are not compressed due to relative rotation of the output disc plates 32 and 33 and the input disc plate 20. Preferably, the uncompressed state does not refer to pre-compression, i.e., compression of springs during assembly to fit into or between parts. Similar to the large coil spring 34, both ends of the small coil spring 35 extend to both ends of the window portion 46 in the rotating direction.
The spring seat 51 is provided at both ends of the large coil spring 34 and the small coil spring 35. As shown in
The supporting end portion 52 is provided at both ends of the large coil spring 34 and the small coil spring 35, in order to support the large coil spring 34 and the small coil spring 35 in a compressing direction. Further, the supporting end portion 52 is formed in a disc shape, includes a convex portion 55 at an opposite side of a surface where the large coil spring 34 and the small coil spring 35 are provided.
The outer periphery covering portion 53 covers and supports the outer periphery of the large coil spring 34. The outer periphery covering portion 53 extends from the supporting end portion 52 to a side where the large coil spring 34 is provided. Further, the outer periphery covering portion 53 is configured to construct a partial cylinder, which is provided along the outer periphery of the large coil spring 34. Each outer periphery covering portion 53 partially covers the large coil spring 34. It should be apparent from this embodiment that the outer periphery covering portion 53 shown in
The projection portion 54 is provided at the inner periphery of the small coil spring 35. The projection portion 54 protrudes from the supporting end portion 52 toward a side where the small coil spring 35 is provided, and thus is a column portion. The projection portion 54 is formed in an approximately cylindrical shape, and is positioned in a state where a center axis 54a of the projection portion 54 preferably overlaps a center axis of end turn portions 35a of the small coil spring 35 and the center axis 54a of the projection portion 54 is preferably eccentric with a center axis 34a of the large coil spring 34. Thus, the center axis of the end turn portions 35a is not the same as the center axis 34a. More particularly, as shown in
Referring now to
With the construction of the dual mass flywheel 1, the torque from the crankshaft 91 of the engine is transmitted to the second flywheel 3 through the damper mechanism 4. In the damper mechanism 4, the torque is transmitted in following order: the input disc plate 20, the coil springs 34-36, and output disc plates 32 and 33. Further, the torque is transmitted from the dual mass flywheel 1 to the clutch disc assembly when the clutch is connected, and eventually, the torque is output to an input shaft (not shown) provided at the transmission side in due course.
When a combustion fluctuation from the engine is input to the dual mass flywheel 1, the input disc plate 20 and the output disc plates 32 and 33 rotate relatively within the damper mechanism 4. Between the aforementioned disc plates, the coil springs 34-36 are parallelly compressed. As shown in
Based on the aforementioned construction, contact of the large coil spring 34 and the window opening 38 provided at the input disc plate can be prevented, even when centrifugal force is imposed on the spring assembly 5 because the outer periphery covering portion 53 is formed on the spring seat 51. Therefore, wear of the large coil spring 34 due to friction between the large coil spring 34 and the window opening 38 provided at the input disc plate can be prevented. Since the projection portion 54 is provided on the spring seat 51, both ends of the small coil spring 35 can avoid being pushed toward the outer periphery of the flywheel. Further, since the small coil spring 35 is made in an arc shape, the large coil spring 34 is unlikely to contact with the center portion in a longitudinal direction of the small coil spring 35, when the spring assembly is compressed by the relative rotation of the input disc plate 20 and of the output disc plates 32 and 33. Consequently, the large coil spring 34 is unlikely to slide with the small coil spring 35 and thus wear in the large coil spring 34 and the small coil spring 35 can be prevented.
The principles and preferred embodiment of the dual mass flywheel 1, which adapts the spring assembly 5 relating to the present invention, have been described in the foregoing specification. However, the invention, which is intended to be protected is not to be constructed as limited to the particular embodiments disclosed. Variations and changes may be made by others, and equivalents employed, without departing from the scope of the present invention.
In understanding the scope of the present invention, the term “comprising” and its derivatives, as used herein, are intended to be open ended terms that specify the presence of the stated features, elements, components, groups, integers, and/or steps, but do not exclude the presence of other unstated features, elements, components, groups, integers, and/or steps. The foregoing also applies to words having similar meanings such as the terms, “including,” “having,” and their derivatives. Also, the terms “part,” “section,” “portion,” “member,” or “element” when used in the singular can have the dual meaning of a single part or a plurality of parts. As used herein to describe the present invention, the following directional terms “forward, rearward, above, downward, vertical, horizontal, below, and transverse” as well as any other similar directional terms refer to those directions of a mechanism equipped with the present invention. Accordingly, these terms, as utilized to describe the present invention should be interpreted relative to a mechanism equipped with the present invention as normally used. Finally, terms of degree such as “substantially,” “about,” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. For example, these terms can be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies.
While only selected embodiments have been chosen to illustrate the present invention, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the invention as defined in the appended claims. Furthermore, the foregoing descriptions of the embodiments according to the present invention are provided for illustration only, and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| JP 2006-215977 | Aug 2006 | JP | national |
