DUAL-TYPE DAMPER DEVICE

Abstract: A dual-type damper (10) for damping vibration of a rotation axle, having (a) a damper pulley (12) including a boss portion (26) joined to the rotation axle, a cylindrical portion (28) located radially outwardly of the boss portion, and a connection portion (30) connecting the boss and cylindrical portions; (b) a first damper mass (14) disposed radially outwardly of the cylindrical portion, concentrically with the same; (c) a first resilient member (16) interposed between the cylindrical portion (28) and the first damper mass (14); (d) a metallic annular member (22) press-fitted onto an inside surface of the cylindrical portion (28); (e) a second damper mass (12) having a cylindrical shape and disposed between the connection portion (30) and the annular member (22), in an inner space of the cylindrical portion, concentrically with the cylindrical portion; and (f) a second resilient member (20) disposed between the annular member and one axial end of the second damper mass (22), so as to secure the second damper mass to the annular member. It also disclosed a dual-type damper having (g) a damper pulley including a cylindrical portion; (h) a first damper mass; (i) a first resilient member; (j) a second damper mass having a cylindrical shape and disposed in an inner space of the cylindrical portion; (k) a second resilient member supporting the second damper mass at one axial end of the same; and (l) a third resilient member mounted on an outside surface of the second damper mass, or on an inside surface of the cylindrical portion.

Description: The present invention relates generally to a dual-type damper device, and more particularly to such a damper device for absorbing vibration of, for example, a rotation axle of an internal combustion engine, so as to reduce vibration and noise caused by the vibration of the rotation axle or the engine. Generally, a rotation axle of an internal combustion engine, such as a crankshaft, is subjected to a variable torque, while being rotated, and the rotation axle or the engine produces very complex vibration and/or noise. The rotation axle may be broken due to the complex vibration. In the above-indicated background art, a method of attaching a flywheel to a rotation axle of an engine of an automotive vehicle, has been employed in order to level the variable torque exerted to the rotation axle. Further, the Japanese Utility Model Applications laid open under Publication No. 55-135838 and No. 56-115050 disclose a so-called dynamic damper device, a torsional damper device which incorporates a secondary vibration system. The torsional damper device has a generally cylindrical shape and is joined to a rotation axle (primary vibration system) of an engine. The secondary vibration system is adapted to resonate with the rotation axle, so as to absorb or restrain vibration and/or noise caused by the vibration of the rotation axle. However, vibration produced by the rotation axle is a complex vibration including two main components, torsional vibration and bending vibration (vibration in directions perpendicular to an axis of the rotation axle), and it takes a variety of vibration modes depending on how the rotation axle or the engine is supported by other members. Conventional dynamic damping devices, such as the torsional damper device as indicated above, have been unsatisfactory in damping such a complex vibration. This is because the torsional damper device as described above is capable of damping the torsional vibration of the rotation axle, but incapable of damping the bending vibration of the same. The torsional damper device effectively restrains the torsional vibration through relative displacement between the damper hub and the damper-mass member (secondary vibration system) due to shear deformation of the cylindrical resilient member therebetween. In order to obtain the desired damping effect on the torsional vibration of the rotation axle, the cylindrical resilient member of the torsional damper device has a comparatively low spring constant in the directions perpendicular to the axis of the rotation axle. Furthermore, the thickness of the resilient member is limited to a small value. The cylindrical resilient member having a low spring constant cannot effectively damp the bending vibration. This is because the resilient member having a low spring constant cannot produce a large tensile or compression deformation to damp the bending vibration. In short, the conventional torsional damper device is effective against the torsional vibration of the rotation axle but ineffective against the bending vibration. US 2,484,281 teaches a damper device for securing to a dynamoelectric machine. The damper device has a circular disc-shaped element of resilient material secured on a stationary part of the machine and a circular weight member secured directly to and concentric with the resilient element. EP 135,646 teaches a rubber clutch wherein a piece of resilient material is located between two machine parts which are moveable relative to each other. JP-A-58-70554 discloses a dual-type damper device for damping vibration of an axle. It has a damper hub including a boss portion joined to the rotation axle, with a cylindrical portion located radially outward of the boss portion and a connection portion connecting the boss portion and the cylindrical portion. The damper device of JP-A-58-70554 also has a damper-mass member and a resilient member. Thus, this document corresponds to the pre-characterising part of claim 1. In JP-A-58-70554 the resilient menber is adjacent the connection portion of the damper hub, and the damper- mass member is integral with the cylindrical portion. The conventional damper devices which are used for absorbing or restraining vibration caused by the rotation axle as discussed above are effective against only the torsional vibration and are not effective against the bending vibration. That is, the conventional damper devices are not effective against vibrations which include both torsional and bending component vibrations. Therefore, those devices do not reduce vibration and/or noise caused by a crankshaft of an internal combustion engine. An around-350-Hz noise caused by the bending vibration of the crankshaft makes an uncomfortable knocking noise. The conventional damper devices are incapable of damping this noise caused by the crankshaft of the internal combustion engine. The present invention may provide a dual-type damper which is jointed to a rotation axle such as a crankshaft of an internal combustion engine and which is capable of damping both torsional vibration and bending vibration (vibration in directions perpendicular to an axis of the rotation axle) of the rotation axle, so as to effectively reduce vibration and/or noise caused by the vibration of the rotation axle or by operation of the engine. According to the present invention, there is provided a dual-type damper device for damping vibration of a rotation axle, comprising: a damper hub including a boss portion joined to said rotation axle; a cylindrical portion located radially outwardly of said boss portion and a connection portion connecting said boss portion and said cylindrical portion a first damper-mass menber; and a first resilient member; wherein the first resilient member is disposed radially outwardly of said cylindrical portion of said damper hub such that said first damper-mass member is spaced apart from, and concentric with, said cylindrical portion; the first resilient member being interposed between said cylindrical portion of said damper hub and said first damper-mass member; and the damper device further includes an annular member made of a metallic material and press-fitted onto an inside surface of said cylindrical portion of said damper hub; a second damper-mass member having a cylindrical shape and disposed between said connection portion of said damper hub and said annular member in an inner space of said cylindrical portion of said damper hub such that said second damper-mass member and said cylindrical portion are concentric with each other; and a second resilient member disposed between said annular member and one of axial ends of said second damper-mass member which is opposed to said annular member, so as to secure said second damper-mass member to said annular member, said second resilient member being subjected to shear deformation thereof due to relative radial displacement between said annular member and said second damper-mass member and wherein the annular member has at least one through-hole for supporting the second resilient member. In the dual-type damper device constructed as described above, the first damper-mass member serves as a first secondary vibration system for damping torsional vibration of the rotation axle (primary vibration system), as in the conventional torsional damper device. That is, the first damper-mass member serves as an effective dynamic damping member for damping the torsional vibration. However, the second damper-mass member serves as a second secondary vibration system for damping bending vibration of the rotation axle. The second resilient member through which the second damper-mass member is secured to the annular member, has a comparatively high spring constant in the directions perpendicular to the axis of the rotation axle. The second resilient member being comparatively soft easily yields to shear deformation thereof, permitting the second damper-mass member to be easily displaced in the directions perpendicular to the axis of the rotation axle. Thus, the second damper-mass member serves as an effective dynamic damping member for damping the bending vibration of the rotation axle. Joined to a rotation axle such as a crankshaft of an internal combustion engine, the dual-type damper device of the present invention effectively restrains vibration caused by the rotation axle, so that vibration and/or noise produced by the rotation axle or the engine are remarkably reduced. A damper device capable of damping both torsional and bending vibrations of a rotation axle is now available for the first time. The second secondary vibration system for damping the bending vibration has a simple construction in which the second damper-mass member is secured to the annular member through the second resilient member vulcanized therebetween, and is easily fixed to the damper hub by means of press-fitting the annular member onto the inside surface of the cylindrical portion of the damper hub. Therefore, the second secondary vibration system, and also the damper device itself, are easily assembled. It is to be appreciated that the second damper-mass member of the second secondary vibration system is disposed within the inner space of the cylindrical portion of the damper hub, such that the second mass is positioned between the connection portion of the hub and the annular member press-fitted onto the inside surface of the cylindrical portion, while secured to the annular member through the second resilient member. If by any chance the second resilient member is broken or fractured due to, for example, deterioration thereof, the annular member serves for stopping the second damper-mass member from falling off the damper device. In view of the above, the dual-type damper device is constructed from a safety point of view. As previously described, the second secondary vibration system of the instant damper device has a simple construction consisting of the second damper-mass member and second resilient member for securing the second damper-mass member to the annular member. A natural frequency of the second secondary vibration system depends upon a mass of the second damper-mass member and upon a spring constant of the second resilient member. Therefore, the natural frequency of the second secondary vibration system is easily tuned to a resonant frequency of the vibration of the rotation axle that is to be damped. The dual-type damper device having the well-tuned second secondary vibration system exhibits a good damping effect against the vibration of the rotation axle including the bending vibration. In an embodiment of the first aspect of the invention, the second damper-mass member is secured to the annular member, in a process of vulcanization of the second resilient member between the one axial end of the second damper-mass member and the annular member. In another embodiment of the first aspect, the first damper-mass member is in the form of a V-ribbed cylindrical body which has in an outside surface thereof a plurality of V-grooves around which at least one V-belt is wound. In still another embodiment, the annular member also serves as stopper means for preventing the second damper-mass member from falling off the dual-type damper device. In a further embodiment of the first aspect, the annular member has at least one through-hole for supporting the second resilient member. The foregoing will be better understood by reading the following description of examples of the invention, when considered in connection with the accompanying drawings, in which: Fig. 1 is a longitudinal cross sectional view of a first embodiment of a dual-type damper according to the present invention; Fig. 2 is a front view of a damper pulley used in the dual-type damper of Fig. 1; Fig. 3 is a cross sectional view taken along line III-III of Fig. 2; Fig. 4 is a longitudinal cross sectional view of a first assembly consisting of a first damper mass, a first resilient body, and a metallic sleeve, which is used in the dual-type damper device of Fig. 1; Fig. 5 is a front view of a second assembly consisting of a second damper mass, a second resilient member, and an annular member, which is used in the dual-type damper device of Fig. 1; Fig. 6 is a cross sectional view taken along line VI-VI of Fig. 5; There will be described in detail embodiments of the present invention, with reference to the accompanying drawings. Referring first to Fig. 1, there is illustrated a dual-type damper 10 constructed according to the present invention. The dual-type damper 10 serves as not only a vibration damper but also a V-grooved hub. Reference numeral 12 designates a damper hub which is located at a central portion of the dual-type damper 10 and which has a generally cylindrical shape. A first damper mass 14 having a cylindrical shape is disposed radially outwardly of the damper hub 12 such that the first damper mass 14 and the damper hub 12 are spaced apart from each other by a predetermined distance and concentric with each other. The first damper mass 14 is made of steel. A first resilient member 16 is interposed between the damper hub 12 and the first damper mass 14. The first resilient member 16 is made of rubber. An annular member 22 is fitted onto an inside surface of a cylindrical portion 28 of the damper hub 12 at one of axial ends of the cylindrical portion 28, so as to be fixed thereto. The damper hub 12 is made of steel. A second damper mass 18 is secured at one of axial ends thereof to one of opposite surfaces of the annular member 22 by means of a second resilient member 20. The second damper mass 18 has a cylindrical shape and is made of steel. The second resilient member 20 is made of rubber. Thus, the second damper mass 18 is disposed in an inner space of the cylindrical portion 28 of the damper hub 12 such that the second damper mass 18 and the damper hub 12 are spaced apart from each other by a predetermined distance and concentric with each other. The damper hub 12 will be illustrated in greater detail hereafter. The damper hub 12 is joined to a rotation axle, such as a crankshaft 8 of an internal combustion engine (Fig. 11), such that the damper hub 12 is rotatable together with the crankshaft 8. As shown in Figs. 2 and 3, the damper hub 12 includes a boss portion 26, the cylindrical portion 28, and a connection portion 30. The boss portion 26 has a cylindrical shape with a smaller diameter than a diameter of the cylindrical portion 28. The boss portion 26 of the damper hub 12 is joined to the crankshaft 8. The cylindrical portion 28 is located radially outwardly of the boss portion 26 such that the cylindrical portion 28 and the boss portion 26 are spaced from each other by a predetermined distance and concentric with each other. The connection portion 30 connects an outer surface of the boss portion 26 and an inner surface of the cylindrical portion 28. The connection portion 30 transverses the inner space of the cylindrical portion 28 in a direction of a diameter of the dual-type damper 10 (hereinafter, referred to as "radial direction"), and divides the inner space into one space in which the boss portion 26 is located and the other space which is longer than the one space in a direction of an axis of the dual-type damper 10 (hereinafter, referred to as "axial direction"). The other space serves as a second-mass space 32 in which the second damper mass 18 is disposed. The first damper mass 14 which is disposed radially outwardly of the damper hub 12 extends as long as the cylindrical portion 28 of the hub 12, as measured in the axial direction of the damper 10. The first mass 14 has in an outside surface thereof, a multitude of V-shaped grooves 34. One or more V-belts (not shown) are fitly wounded around the V-shaped grooves 34. Thus, the damper hub 12 serves as a V-belt driving hub for tranferring rotating or driving power from the crankshaft 8 to other members. Referring next to Fig. 4, there is illustrated the first resilient member 16 which is interposed between the damper hub 12 and the first damper mass 14. Between the first resilient member 16 and the damper hub 12 there is interposed a metallic sleeve 36 which has a cylindrical shape with a thin wall and which extends as long as the cylindrical portion 28 of the hub 12. The metallic sleeve 36 is located radially inwardly of the first damper mass 14 such that the sleeve 36 and the first mass 14 are spaced apart from each other by a predetermined distance and concentric with each other. A first assembly consisting of the first damper mass 14, first resilient member 16 and metallic sleeve 36 is press-fitted onto an outside surface of the cylindrical portion 28 of the damper hub 12, to provide the dual-type damper 10. As shown in Figs. 5 and 6, the second damper mass 18 which is disposed within the second-mass space 32 of the damper hub 12 and which has a cylindrical shape, is secured at one of axial ends thereof to one of opposite surfaces of the metallic annular member 22, by means of the annular, second resilient member 20 inserted therebetween. The second damper mass 18 and the annular member 22 have the same center line (axis) extending in the axial direction of the damper 10, after they are secured to each other. The annular member 22 has an outside diameter larger than that of the second damper mass 18 by a predetermined valve. The second resilient member 20 has a predetermined thickness. The annular member 22 has half a dozen through-holes 38 formed therethrough in the axial direction. The through-holes 38 are equiangularly spaced from each other, circumferentially of the annular member 22. The second resilient member 20 is brought in the through-holes 38 when vulcanized, which enhances the fixation between the second damper mass 18 and the annular member 22. As shown in Fig. 1, the annular member 22 having the second damper mass 18 is fitted onto the inside surface of the cylindrical portion 28 of the damper hub 12, at one of axial ends of the cylindrical portion 28, such that the second damper mass 18 is disposed in the second-mass space 32 of the cylindrical portion 28, concentrically with the cylindrical portion 28. Thus, the second damper mass 18 is supported by the damper hub 12 through the second resilient member 20, concentrically with the damper hub 12. It is to be appreciated that the outside diameter of the second damper mass 18 is dimensioned smaller than an inside diameter of the cylindrical portion 28 of the damper hub 12 by a predetermined valve. This arrangement permits the second damper mass 18 to be displaced or moved relative to the annular member 22, by a predetermined distance in the radial direction, due to shear deformation of the second resilient member 20. Next, a process for manufacturing the dual-type damper 10 constructed as described hitherto will be illustrated below. First, the first damper mass 14 and the metallic sleeve 36 are held in a concentric relationship with each other, and the first resilient member 16 is formed by vulcanizing a suitable rubber material between the two members 14 and 36. Consequently, the first mass 14 and the sleeve 36 are fixed to each other through the vulcanized first resilient member 16, and the first assembly of the three members 14, 16 and 36 is obtained. On the other hand, the second damper mass 18 and the annular member 22 are held such that the two members 18 and 22 lie on the same axis, and so that the two members 18 and 22 are spaced from each other by a predetermined distance. A suitable rubber material is injected through the through-holes 38 of the annular member 22 into a space between the second mass 18 and the annular member 22. The injected rubber material is vulcanized in that space so as to form the second resilient member 20. The second mass 18 is connected at one axial end thereof to one of opposite surfaces of the annular member 22 which is opposed to that one axial end of the second mass 18. Thus, the second assembly is obtained. The second assembly is secured to the damper hub 12 in the process of press-fitting the annular member 22 of the second assembly, onto the inside surface of the cylindrical portion 28 of the damper hub 12. Subsequently, the first assembly of the first damper mass 14, first resilient member 16 and metallic sleeve 36 is press-fitted onto the outside surface of the cylindrical portion 28 of the hub 12. Thus, the dual-type damper device 10 is obtained. In this connection, it is to be appreciated that the outside diameter of the annular member 22 is dimensioned larger than an inside diameter of the cylindrical portion 28 of the damper hub 12 by a predetermined valve. This arrangement provides a firm fixation between the annular member 22 and the damper hub 12. It is also to be appreciated, that an inside diameter of the metallic sleeve 36 is smaller than an outside diameter of the cylindrical portion 28 of the damper hub 12 by a predetermined valve. This arrangement permits the first resilient member 14 to be pre-compressed, and the first assembly to be firmly fixed to the damper hub 12. The dual-type damper 10 manufactured in the above-described process serves for the internal combustion engine, with an inside surface of the boss portion 26 of the hub 12 joined to the crankshaft 8 of the engine. In the dual-type damper 10 of the invention, torsional vibration (vibration in the circumferential direction of the damper 10) caused by rotation of the crankshaft 8 to which the damper hub 12 is joined, is effectively damped through vibration of the first damper mass 14 in the circumferential direction of the damper 10. The first resilient member 16 is deformed due to relative displacement between the hub 12 and the first mass 14 in the circumferential direction. Thus, the first damper mass 14 serves as a first damping member (first secondary vibration system) for damping the torsional vibration. On the other hand, bending vibration (vibration in the radial direction of the damper 10) caused by rotation of the crankshaft 8 is effectively damped through radial vibration of the second damper mass 18. The second resilient member 20 is deformed due to relative displacement between the hub 12 and the second damper mass 18 in the radial direction of the damper 10. Thus, the second mass 18 serves as a second damping member (second secondary vibration system). Complex vibration caused by the crankshaft 8 has two major components, the torsional vibration and the bending vibration. The instant dual-type damper 10 is capable of effectively absorbing both the torsional and bending vibrations. Consequently, vibration and/or noise produced by the internal combustion engine is remarkably reduced by the instant damper 10. In the case where the instant damper 10 is used with an engine of an automotive vehicle, the damper 10 remarkably restrains noise experienced in the passenger's room, particularly the uncomfortable knocking noise caused by an around-350-Hz vibration which has not been restrained by conventional torsional dampers. The second secondary vibration system of the damper 10 against the bending vibration is assembled of the second damper mass 18, annular member 22, and second resilient member vulcanized between the two members 18 and 22, and secured to the damper hub 12 by press-fitting the annular member 22 onto the inside surface at the end of the cylindrical portion 28 of the damper hub 12. Thus, the second secondary vibration system, and also the damper 10, are easily assembled. Further, the second damper mass 18 and the damper hub 12 are accurately and easily positioned relative to each other on the same axis. This is because the second damper mass 18 is disposed in the second-mass space 32 by means of press-fitting the second assembly onto the inside surface of the cylindrical portion 28 of the hub 12. Consequently, the number of inferior goods (damper devices) which have a second damper mass 18 at an inaccurate position is decreased. The second damper mass 18 is disposed within the second-mass space 32 of the damper hub 12, such that the second mass 18 is positioned between the connection portion 30 of the hub 12 and the annular member 22 press-fitted onto the inside surface at the end of the cylindrical portion 28 of the hub 12, and secured to the annular member 22 through the second resilient member 20. If by any chance the second resilient member 20 is broken, the annular member 22 will serve as a fail-safe mechanism for stopping the second mass 18 from falling off (springing out of) the second-mass space 32. The instant dual-type damper 10 is very safe in this point of view. As previously described, the second secondary vibration system for damping the bending vibration has a simple construction. A natural frequency of the second secondary vibration system depends upon a mass of the second damper mass 18 and upon a spring constant of the second resilient member 20. The natural frequency of the second secondary vibration system can be easily tuned to a resonance frequency of the vibration of the crankshaft 8 that is to be damped. Although the annular member 22 has the through-holes 38 for supporting the second resilient member 20, an annular member 22 without such through-holes may be usable in the instant dual-type damper 10. The dual-type damper of the present invention is not limited to use for a crankshaft of an internal combustion engine. The dual-type damper is serviceable for various kinds of rotation axles which produce vibration, with good results as described about the illustrative embodiments. Although the illustrative embodiments of the dual-type vibration damper also serve as a V-ribbed hub, the V-shaped grooves are not essential for the present invention. In other words, the dual-type damper of the invention may be designed to serve only as a vibration damper for damping vibration of a rotation axle. In the illustrative embodiments of the dual-type damper, the first damper mass 14 is connected to the metallic sleeve 36 through vulcanization of the first resilient member 16 therebetween, and the thus-formed assembly is press-fitted onto the outer surface of the cylindrical portion 28 of the damper hub 12. The metallic sleeve 36 located innermost of the assembly is useful for the press-fitting. However, an important rule is that the first damper mass 14 is secured to the damper hub 12 by way of the first resilient member 16 therebetween. Therefore, the first damper mass 14 may be press-fitted onto an outside surface of the metallic sleeve 36 located outermost of an assembly which consists of the metallic sleeve 36, hub 12, and first resilient member 16 vulcanized between the sleeve 36 and hub 12. Furthermore, the first damper mass 14 may be connected to the damper hub 12 through vulcanization of the first resilient member 16 between the first mass 14 and hub 12. In this case, the metallic sleeve is omitted.

Claims: A dual-type damper device (10) for damping vibration of a rotation axle, comprising: a damper hub (12) including a boss portion (26) joined to said rotation axle (8); a cylindrical portion (28) located radially outwardly of said boss portion (26) and a connection portion (30) connecting said boss portion (26) and said cylindrical portion (28); a first damper-mass member (14); and a first resilient member (16); characterised in that: the first resilient member (16) is disposed radially outwardly of said cylindrical portion (28) of said damper hub (12) such that said first damper-mass member (14) is spaced apart from, and concentric with, said cylindrical portion (28); the first resilient member (16) being interposed between said cylindrical portion (28) of said damper hub (12) and said first damper-mass member (14); and the damper device further includes: an annular member (22) made of a metallic material and press-fitted onto an inside surface of said cylindrical portion (28) of said damper hub (12); a second damper-mass member (18) having a cylindrical shape and disposed between said connection portion (30) of said damper hub (12) and said annular member (22), in an inner space of said cylindrical portion (28) of said damper hub (12), such that said second damper-mass member (18) and said cylindrical portion (28) are concentric with each other; and a second resilient member (20) disposed between said annular member (22) and one of axial ends of said second damper-mass member (18) which is opposed to said annular member (22), so as to secure said second damper-mass member (18) to said annular member (22), said second resilient member (20) being subjected to shear deformation thereof due to relative radial displacement between said annular member (22) and said second damper-mass member (18) and wherein the annular member (22) has at least one through-hole (38) for supporting the second resilient member (20). A dual-type damper device (10) according to claim 1, wherein said second damper-mass member (18) is secured to said annular member (22), in a process of vulcanization of said second resilient member (20) between said one axial end of said second damper-mass member (18) and said annular member (22). A dual-type damper device (10) according to claim 1 or claim 2 wherein said first damper-mass member (14) is in the form of a V-ribbed cylindrical body which has in an outside surface thereof a plurality of V-grooves (34) around which at least one V-belt is wound. A dual-type damper device (10) according to claim 1, claim 2 or claim 3 wherein said annular member (22) also serves as stopper means for preventing said second damper-mass member (18) from falling off the dual-type damper device (10).

Inventors: SERIZAWA, MINORU C/O TOKAI RUBBER IND. LTD., TAZUKE, YUTAKA C/O TOKAI RUBBER IND. LTD.
Applicants: TOKAI RUBBER INDUSTRIES, LTD., TOYOTA JIDOSHA KABUSHIKI KAISHA
Application year: 1986
Main classification: F16F15
IPC codes: F16F15, F16H55