INERTIA DAMPER

Abstract: An inertia damper has a mounting base (10) to be mounted on a rotary shaft (40) and an inertia weight component (20) which is coupled to the mounting base through a vibration absorbing layer so the vibration absorbing layer being made of a gel material with a penetration value of approximately 50 to 200. The inertia weight component is adhered to one surface of the vibration absorbing layer and the other surface of the vibration absorbing layer is adhered to the mounting base of the rotary shaft. A vibration wave generated at the rotary shaft side is dispersedly absorbed by deformation of gel material which forms the vibration absorbing layer and a vibratory component can be removed from a braking motion.

Description: The present invention relates to an inertia damper, and in particular to a damper for preventing vibration of the rotary shaft of apparatus such as, for example, a stepping motor or the like which undergoes frequent repeating start and stop motion. In a stepping motor, the rotation should accurately follow the input pulse and it is necessary to eliminate resonance and any unstable phenomenon which may be caused during operation. Therefore, it is necessary to reduce the braking time which is the transient response characteristic of the stepping motor, and such reduction can be achieved by quickly controlling the vibration of the transient response characteristic. For this reason, a conventional stepping motor is provided with an inertia damper at its rotary shaft to control an inertia moment which acts on the rotary shaft. Such an inertia damper is available as an electrical type and a mechanical type. The electrical type inertia damper is based on a capacitor damping system or a magnetic mounting system, while the mechanical inertia damper uses an elastic member or a viscous fluid. A mechanical inertia damper using an elastic member is disclosed in Japanese Patent Gazette for Laid Open SHO 61-9156 and a damper using viscous fluid is disclosed in Japanese Patent Gazette for Laid Open SHO 58-123362. Another viscous fluid damper is disclosed in US-A-4563605. Of the above mechanical inertia dampers, however, the inertia damper using the elastic member is provided with an elastic member made of an elastic material such as, for example, rubber as a fitting means between a mounting base fixed on the rotary shaft and the inertia weight component, and therefore there is a problem that a repulsive elasticity is produced in the elastic member when the inertia moment is absorbed and a new vibration may be produced by this repulsive elasticity and the damper is inferior in absorptivity of inertia moment. The inertia damper using a viscous fluid also has a problem in that an oil seal for sealing the fluid is required and production costs are high due to the strict machining accuracy required. According to the present invention there is provided an inertia damper comprising a mounting base to be mounted on a rotary shaft, a vibration absorbing layer one surface of which is coupled to said mounting base and an inertia weight component which is coupled to the other surface of said vibration absorbing layer and to said mounting base through said vibration absorbing layer, wherein said vibration absorbing layer is made of a gel material with a penetration value of approximately 50 to 200. By means of this arangement there is provided an inertia damper which can be easily sealed between the mounting base and the inertia weight component and uses a vibration absorbing layer with an extremely small repulsive elasticity. Throughout this specification references to the penetation value are references to the penetration as measured in accordance with Japanese Industrial Standard JlS K 2530-1976-(50g load). Since the gel material has a characteristic which absorbes an external energy by non-elastic deformation and a vibration propagating characteristic similar to a liquid, the vibration wave applied to the vibration absorbing layer is dispersedly propagated to the whole vibration absorbing layer and fractionized and absorbed by non-elastic deformation of the vibration absorbing layer as a whole. Since the gel material is not a liquid, it can be inserted between the inertia weight component and the mounting base fixed on the rotary shaft without using a strict sealing means such as, for example, oil seal and therefore the disadvantages regarding the seal of the conventional inertia damper using viscous fluid can be eliminated. The vibration absorbing layer made of gel material adheres to the fitting surface of the mounting base and the fitting surface of the inertia weight component with its own adhesiveness and has a characteristic that it does not excel in the self profile maintainability and therefore, when the vibration absorbing layer receives a shock in a direction parallel to the fitting surface where a frictional contact takes place, the vibration absorbing layer may come off the fitting surface. In preferred embodiments, a recessed portion is formed at each of opposing central parts of the fitting surface of the mounting base and the fitting surface of the inertia weight component which is opposed to said fitting surface of the mounting base and the inertia damper is adapted so that a part or all of each fitting surface of the vibration absorbing layer is pushed into each recessed portion. In such construction, at least a part of the fitting surface of the vibration absorbing layer engages as a wedge with the fitting surface of the inertia weight component side and the fitting surface of the mounting base side and therefore the vibration absorbing layer can be prevented from being separated or coming off from the inertia weight component and the mounting base and the vibration absorbing surface of the vibration absorbing layer can be enlarged. Accordingly, in this way there is provided the inertia damper capable of firmly maintaining the vibration absorbing layer made of gel material between the mounting base and the inertia weight component. In general, to form the vibration absorbing layer between the inertia weight component and the mounting base, the mounting base to be mounted on the rotary shaft may be loosely fitted into the center hole provided in advance at the inertia weight component and silicone gel original fluid is poured between the inertia weight component and the mounting base, then the silicone gel original fluid is heated to be gelled. However, the method is not suitable to volume production since the inertia weight component and the mounting base are heat-treated as they are assembled. In preferred embodiments the present invention provides an inertia damper in which the vibration absorbing layer can be easily inserted between the inertia weight component and the mounting base. In the present invention, in certain embodiments, a separate component of the vibration absorbing layer is made by gelling in advance silicone gel original fluid in the shape of an O-ring and this vibration absorbing layer is disposed between the inertia weight component and the mounting base. After the O-ring type vibration absorbing layer has been made as a separate component, the non-tacking skin layer is formed on its surface and adhered with an adhesive agent to the fitting surface of the inertia weight component and that of the mounting base. In further embodiments, the central part of one fitting surface of either of the mounting base and the inertia weight component is formed to be protruded at least at its part and the other fitting surface is provided with a recessed portion which meshes with the protruded part of the opposing fitting surface and said inertia weight component is prevented from coming off in the axial direction of the rotary shaft at least at its part and kept engaged with the mounting base through the vibration absorbing layer made of gel material. In this way there may be provided an inertia damper for which the mounting base and the inertia weight component, which are concentrically mounted on the rotary shaft, are combined so that the inertia weight component does not come off the mounting base. In one embodiment, the inertia weight component is made up by stacking a plurality of doughnut-shaped annular disks so that the weight of the inertia weight component can be varied by increasing or decreasing the number of disks. In this way it is possible to adjust the weight of the inertia weight component to be adapted to the load torque. The inertia weight component is loosely fitted to the outside of the mounting base and the vibration absorbing layer made of a gel material is formed between the mounting base and the inertia weight component. Some embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which:- Figure 1 is a front view of an inertia damper in accordance with an embodiment of the present invention. Figure 2 is a cross-sectional view of the inertia damper shown in Figure 1, Figures 3 to 6 are front views showing other embodiments of the inertia damper in accordance with the present invention, Figure 7 is a vertical cross-sectional side view showing another embodiment of the inertia damper in accordance with the present invention, Figure 8 is a graph showing the braking characteristic of the inertia damper shown in Figure 1, Figure 9 is a vertical cross-sectional side view showing another further embodiment of the inertia damper in accordance with the present invention, Figure 10 is a front view of the inertia damper shown in Figure 9, Figures 11 and 12 are a vertical cross-sectional side views showing another further embodiments of the inertia damper in accordance with the present invention, Figure 13 is a vertical cross-sectional front view of the inertia damper shown in Figure 12, Figures 14 to 17 are vertical cross-sectional side views showing further embodiments of the inertia damper in accordance with the present invention, Figure 18 is a front view of the inertia damper shown in Figure 17, Figures 19 and 20 are vertical cross-sectional side views showing further embodiments of the inertia damper in accordance with the present invention, Figure 21 is a front view showing another further embodiment of the inertia damper in accordance with the present invention, Figure 22 is a vertical cross-sectional side view showing the magnified principal part of the inertia damper shown in Figure 19, Figure 23 is a vertical cross-sectional side view showing another further embodiment of the inertia damper in accordance with the present invention, Figure 24 is a front view of the inertia damper shown in Figure 23, Figure 25 is a disassembled perspective view of the mounting base and the inertia weight component of the inertia damper shown in Figure 23, and Figures 26 to 30 are vertical cross-sectional side views showing another further embodiments of the inertia damper in accordance with the present invention. Referring to Figures 1 and 2, there is shown an inertia damper comprising a mounting base 10 and an inertia weight component 20 which is coupled to said mounting base 10 with a vibration absorbing layer 30 made of gel material. The mounting base 10 is provided with a groove 111 which extends in the circumferential direction at the central part of the peripheral surface of the fitting surface 11. The mounting base 10 has a shaft hole 12 into which a rotary shaft 40 is inserted and fixed. Depending on the case, the mounting base 10 can be made to be integral with the rotary shaft. The inertia weight component 20 is made as a thick doughnut type disk with a large diameter hole at its center and provided with a groove 211 which extends in the circumferential direction at the central part of the wall surface of said hole as a fitting surface 21. The inertia weight component 20 is loosely fitted to the outside of the mounting base 10 and the vibration absorbing layer 30 made of gel material such as, for example, silicone gel material is formed between the inertia weight component 20 and the mounting base 10. This vibration absorbing layer 30 adheres to the mounting base 10 with its one surface and to the fitting surface 21 of the inertia weight component 20 with its other surface, and accordingly, the inertia weight component 20 is fixed to the mounting base 10 through the vibration absorbing layer 30. The vibration absorbing layer 30 is made of gel material with the penetration value of approximately 50 to 200 and silicone gel is suitable as this material. If the penetration value of gel material is less than 50, the deformation of the vibration absorbing layer 30 is insufficient and, if the penetration value exceeds, the fluidity will be high and the deformability of the vibration absorbing layer will be excessive. If silicone gel is used as the gel material, such method can be adopted that the inertia weight component 20 is externally fitted to the mounting base 10 and silicone gel original fluid is poured between the inertia weight component 20 and the mounting base 10 to be gelled by heating. For this method,the inertia weight component 20 is provided with a fluid inlet port 22 leading to the groove 211 and silicone gel is supplied to the groove 211 through this fluid inlet port 22 and gelled by heating. If silicone gel is thus used as gel material, the vibration absorbing layer 30 can adhere to the fitting surfaces 11 and 21 by means of the tackiness of silicone gel when silicone gel original fluid is gelled. Toray Silicone CF5027 (trademark) made by Toray Silicone Kabushiki Kaisha and KE-1051 (product name) made by Shinetsu Kagaku Kabushiki Kaisha are available as said silicone gel and the compound type silicone gel prepared by mixing fine hollow particles such as, for example, Fillite (trademark) made by Nippon Fillite Kabushiki Kaisha and Expancel (trademark) made by Nippon Fillite Kabushiki Kaisha can be used. This compound type silicone gel is light and inexpensive and therefore it is advantageous in weight reduction and cost saving of the inertia damper. Particularly, the compound type silicone gel in which said Fillite is mixed has a high heat resistance and is suitable for this inertia damper. This compound type silicone gel is disclosed in the U.S. Patent Application Serial No. 87970 filed on August 17, 1987. The inertia damper shown in this embodiment can absorb the vibration wave generated from the rotary shaft 40 by non-elastic deformation of the vibration absorbing layer 30 while diffusing the vibration wave in the vibration absorbing layer 30. In other words, the vibration wave conducted from the rotary shaft 40 is absorbed in the vibration absorbing layer 30 by deformation of said layer while causing a correlative motion between the inertia weight component 20 and the mounting base 10. In this case, the deformation of the vibration absorbing layer 30 is non-elastic deformation and therefore the vibration wave can be absorbed without causing a repulsive elasticity. Since the gel material has the vibration wave propagating characteristic similar to liquid as described above, the vibration wave is fractionized into the vibration absorbing layer and quickly converted to heat. In the above description, "non-elastic deformation" means that such remarkable deformation as in rubber or spring is not provided and the elasticity is not zero in deformation, and the phenomenon that no repulsive elasticity is provided means that the repulsive elasticity is extremely smaller than rubber and spring and does not mean that the repulsive elasticity is zero. In the inertia damper shown in this embodiment, it is clear that the braking time t1 shown with the solid line in Figure 8 is extremely smaller than the braking time t2 of the conventional elastic member type inertia damper shown with the broken line. In Figure 8, T denotes the time and A denotes the angle of rotation. The inertia damper in accordance with the present invention can be adapted as shown in Figures 3 to 7. The embodiment shown in Figure 3 is an inertia damper made up by alternately protruding at least a part of the fitting surface 11 of the mounting base 10 and the fitting surface 21 of the inertia weight component 20 in the radial direction so that these protruded portions 111' and 211' are gear-meshed, and providing the vibration absorbing layer 30 between both fitting surfaces 11 and 21. According to this embodiment, the thickness of the vibration absorbing layer 30 can be increased and the inertia moment applied to the inertia weight component 20 is transmitted from the protruded portion 111' of the fitting surface 11 of the mounting base 10 to the protruded portion 211 of the fitting surface 21 of the inertia weight component 20 through the vibration absorbing layer 30. Accordingly, the vibration absorbing layer 30 is deformed to absorb the vibration wave while being depressed in the circumferential direction. Figure 4 shows an inertia damper with a widened vibration absorbing layer 30 and, in this embodiment, an improvement of the vibration absorbing effect can be expected in a specific frequency. The embodiment shown in Figure 5 is an inertia damper in which a number of recessed portions 112 and 212, which are opposed each other, for example a number of circular spaces,are provided at specified distances on the fitting surfaces 11 and 12 of the mounting base 10 and the inertia weight component 20 and the vibration absorbing layer 30' is formed in these circular spaces. In this embodiment, when the inertia moment in the circumferential direction is applied to the inertia weight component 20, the vibration absorbing layer 30 is depressed in the circumferential direction and deformed to absorb the vibration wave. The embodiment shown in Figure 6 is an inertia damper in which at least one vibration absorbing layer 201 is provided in the inertia weight component 20, which is made up by concentrically assembling a plurality of doughnut type annular members 23, 24 and 25 between which vibration absorbing layers 201 and 201' made of gel material with the penetration value of approximately 50 to 200 such as, for example, silicone gel are inserted. According to this embodiment, the inertia weight component can internally absorb the vibration wave. The embodiment shown in Figure 7 is an inertia damper made up by forming the fitting surface 11' which is extended like a disk around the shaft hole 12' on the front face of the mounting base 10, providing the peripheral edge 13 on this fitting surface 11' to accommodate a disk type inertia weight component 20, making the fitting surface 21' opposed to the fitting surface 11' of the mounting base 10 and inserting the vibration absorbing layer 30 between both fitting surfaces 11' and 21'. In this embodiment, the inertia weight component 20 can serve as a cover to prevent adhesion of dust to the vibration absorbing layer 30. In each above embodiment, as shown, for example, in Figures 1 and 5, the clearance between the inertia weight component 20 and the mounting base 10 can be maintained fixed by providing ball bearings 50 between the inertia weight component 20 and the mounting base 10, and also the cover 26 for sealing the clearance between the free edges of the inertia weight component 20 and the mounting base 10 can be provided on the inertia weight component 20 or the mounting base 10 as shown with the broken line in Figure 1. Referring to Figures 9 to 13, there is shown another embodiment of the inertia damper in accordance with the present invention. For convenience of the description, the mounting base 10, inertia weight component 20 and vibration absorbing layer 30 described below are considered similar to those described in the foregoing paragraphs and the detailed description of these components is omitted. The embodiment shown in Figure 9 is an inertia damper in which the vibration absorbing layer 30 formed between the mounting base 10 and the inertia weight component 20 is thin at both sides of the circumferential direction and thick at the central portion. In this embodiment, grooves 111 and 211 as shown in Figure 1 are provided on the fitting surface 21 of the inertia weight component 20 and the fitting surface 11 of the mounting base 10 and filled with the vibration absorbing layer 30. The inertia damper of this embodiment, as shown in Figure 10 is such that the vibration absorbing layer 30 completely separates the fitting surface 21 of the inertia weight component 20 and the fitting surface 11 of the mounting base 10 and therefore the vibration absorbing layer 30 is formed by thin edge portions 31 and 31' at both sides and a thick engaging portion 32 at the center. In this embodiment, the vibration absorbing layer 30 has the thick engaging portion 32 at the center and, even if an external force is applied to the inertia weight component 20 from the axial direction of the rotary shaft 40, the inertia weight component 20 can powerfully engage with the mounting base 10 by virtue of the engaging force of the engaging portion 32 and can thus be prevented from comming off from the mounting base 10. The shape of said engaging portion 32 can be changed as desired in accordance with the shape of grooves 111 and 211; for example, the vibration absorbing layer 30 can be square-protruded at its center as shown in Figure 11. In this embodiment, side edge portions 31 and 31' of the vibration absorbing layer 30 are provided with external edges 311 and 311' which are formed as the non-tacking skin layer and such formation of the skin layer is disclosed in Japanese Patent Gazette for Laid Open SHO 61-51035 and Japanese Patent Gazette for Laid Open SHO 62-3839. The engaging portion 32 of said vibration absorbing layer 30 can be partly formed as shown in Figures 12 and 13. In this case, as shown in Figure 13, at least one engaging portion can be provided in the circumferential directions of the mounting base 10 and the inertia weight component 20. However, it is preferable to provide a plurality of engaging portions. Referring to Figures 14 to 16, there are shown other embodiments of the inertia damper in which an inertia weight component 20 as shown in Figures 9 to 13 is provided to engage with the mounting base 10. The inertia dampers shown in Figures 14 and 15 are provided with a ridge 113 or 213 which extends in the circumferential direction on the fitting surface of either of the inertia weight component 20 and the mounting base 10 as an engaging means and the groove: 114 or 214 which extends in the circumferential direction on the fitting surface of the other member as an engaging means whereby the ridge is fitted into this groove to combine the inertia weight component 20 with the mounting base 10 and the vibration absorbing layer 30 made of gel material is interpositioned between the ridge 113 or 213 and the groove 114 or 214. In this embodiment, since the ridge is engaged with the groove, the inertia weight component 20 is engaged with the mounting base 10 to be prevented from comming off even though a force from the axial direction of the rotary shaft is applied to the inertia weight component 20. In the inertia damper shown in this embodiment, the inertia weight component 20 is made as a split type as shown in Figure 15 or the mounting base 10 is made to be partly dividable at its part 101 as shown with the broken line in Figure 14 so that the groove114 or 214 can be easily formed. The ridge 113 or 213 as said engaging means can be a cover piece 27 provided on the inertia weight component 20 as shown in Figure 16, and this cover piece 27 is made of a rigid material such as, for example, metal or the like and its both extreme ends are extended outside the mounting base 10 as free ends. In this embodiment, the engaging means in the external wall surface of the mounting base 10 and the inertia weight component 20 is prevented from coming off from the mounting base 10 by engagement of the free ends of the cover piece 27 with the mounting base as the engaging portions 271 and 271' when the inertia weight component 20 is moved by a force in the axial direction of the rotary shaft. The cover piece 27 can be fixed on the mounting base 10. In this case, the free ends of the cover piece 27 as the engaging ends are extended outside the inertia weight component 20 and the external wall surface of the inertia weight component 20 is used as the engaging means. Referring to Figures 17 to 21, there is shown an inertia damper for which the vibration absorbing layer 30 is made in advance as a separate member. According to this embodiment, the vibration absorbing layer 30 is made without using the method for pouring the silicone gel original fluid between the inertia weight component 20 and the mounting base 10 and gelling it through heating. The vibration absorbing layer 30 is made in advance in the shape of ring by gelling silicone gel material with a mold used in the other process and the non-tacking skin layer 33 is formed on the external surface of this annular vibration absorbing layer 30. The method by which silicone gel material is thus poured into the mold to be gelled and the non-tacking skin layer 33 is formed on the surface of silicone gel is disclosed in Japanese Patent Gazette for Laid Open SHO 61-51035 and Japanese Patent Gazette for Laid Open SHO 62-13839. The annular vibration absorbing layer 30, as shown in Figures 17 and 18, is accommodated in the space formed between the inertia weight component 20 and the mounting base 10 and adhered and fixed to the fitting surface 21 of the inertia weight component 20 and the fitting surface 11 of the mounting base 10 with the adhesive agent 34 applied to the skin layer 33 as shown in Figure 22. The space formed between the mounting base 10 and the inertia weight component 20 can be made by selecting the shape described in aforementioned embodiments. Since the vibration absorbing layer 30 is handled as a separate component in this embodiment, part 102 or 202 of the inertia weight component 20 or the mounting base 10 is made separable as shown in Figures 17 and 20 and the space is designed so that the vibration absorbing layer 30 can be accommodated in the space by removing the part 102 or 202. The vibration absorbing layer 30 can be made cylindrical as shown in Figure 21. In this case, the cylindrical vibration absorbing layer 30 can be accommodated in the grooves 115 and 215 which are provided with a specified distance to intersect at right angles to the circumferential direction of the fitting surfaces 11 and 21 of the inertia weight component 20 and the mounting base 10. The embodiment shown in Figure 19 is an inertia damper in which the ring type vibration absorbing layer 30 is adhered to the fitting surface 21 of the inertia weight component 20 and the fitting surface 11 of the mounting base 10 by applying the adhesive agent to both upper and lower portions of the skin layer 33, and both right and left sides of the skin layer 33 of the vibration absorbing layer 30 are exposed to outside. In this embodiment, the ring type vibration absorbing layer 30 can be prepared as a separate component as described above. As another method, the grooves which oppose each other are provided on the inertia weight component 20 and the mounting base 10 as shown in Figure 1, a large amount of adhesive agent enough to form the skin layer 33 is applied in advance to the grooves, the inertia weight component 20 is loosely fitted to the outside of the mounting base 10, silicone gel original fluid is poured into the grooves and then heated to be gelled to form the vibration absorbing layer 30, and the skin layer 33 can be formed on the surface of the vibration absorbing layer. This method is advantageous in that the skin layer 33 can be adhered to the fitting surface 21 of the inertia weight component 20 and the fitting surface 11 of the mounting base 10 at the same time as the skin layer 33 is formed. In the embodiment in which the skin layer 33 is formed on the vibration absorbing layer 30, the vibration absorbing layer 30 can be firmly adhered to the fitting surfaces 21 and 11 with the skin layer 33 of large strength and, even though an external force from the axial direction of the rotary shaft is applied to the inertia weight component 20, the inertia weight component can be prevented from comming off from the mounting base 10. Referring to Figures 23 to 30, there are shown the inertia dampers capable of adjusting the weight of the inertia weight component 20. According to this embodiment, the inertia weight component 20 can be adjusted to meet the load torque and therefore the braking effect of each inertia damper can be individually improved. In the embodiment shown in Figures 23 to 25, the inertia weight component 20 is made up by concentrically stacking a number of doughnut type annular disks 28 and the weight of the inertia weight component 20 is varied by varying the number of disks 28. In this embodiment, the fitting surface 11 of the mounting base 10 is made up by stacking doughnut type disks 103. For this, a part of the mounting base 10 is provided as a fitting part 104 on which disks 103 to be fitted are fixed. The inertia weight component 20 is made up by alternately stacking a plurality of disks 28, which are therefore integrally assembled by welding or by an adhesive agent or by a fitting means such as screws. Furthermore in this embodiment, the mounting base 10 is made up by assembling disks 103 with a similar fitting means to the inertia weight component 20 and thus the length of the fitting surface 11 of the mounting bases 10 can be coincided with that of the fitting surface 21 of the inertia weight component 20. In this embodiment, the inertia weight component 20 is made so that the space at the central part in the axial direction can be expanded. To obtain this construction, the center holes of front and rear disks 28' in the axial direction are made to have a small diameter and the center holes of disks 28 at the central part are made to have a large diameter. This inertia weight component 20 is concentrically fitted to the outside of the mounting base 10, which is made so that the center in the axial direction is expanded. To obtain this construction, the disks at the mounting base 10 side are made so that each two disks 103' at both sides in the axial direction are made to have a small diameter and the disk 103 at the center is made to have a large diameter. Accordingly, the vibration absorbing layer 30 in this embodiment is formed to be expanded toward the outside of the center in the axial direction as shown in Figure 23, and the inertia weight component 20 is prevented from coming off in the axial direction since the outside disk 28' engages with the center disk 103 at the mounting base 10 side in the axial direction. In other words, this embodiment provides the same effect for preventing the inertia weight component 20 from coming off as in case of the embodiment shown in Figures 14 and 15. If the shape of the inertia weight component 20 is as shown in Figures 3 to 5, said disks 28 and 103 can be made in accordance with the type of inertia weight component 20 and the mounting base 10. Figures 26 to 30 respectively show another further embodiment of the inertia damper which has the inertia weight component 20 which is thus assembled with the disks 28. The embodiment shown in Figure 26 is an inertia damper which provides the coming-off preventing effect for the inertia weight component 20 similar to the embodiment shown in Figures 2 and 9 and the vibration absorbing layer 30 is formed to have a large wall thickness in the chamber formed by the groove 211 formed on the fitting surface 21 of the inertia weight component 20 and the groove 111 formed on the fitting surface 11 of the mounting base 10. The embodiment shown in Figure 27 shows the inertia damper in which only the inertia weight component 20 is made up by stacking disks 28. The vibration absorbing layer 30 of this embodiment is such that the external surface of the vibration absorbing layer 30 is made as the non-tacking skin layer 33, which is adhered and fixed to the fitting surface 21 of the inertia weight component 20 and the fitting surface 11 of the mounting base 10, and both sides of the skin layer 33 in the axial direction are exposed to outside. Such vibration absorbing layer 30 as described above is described in detail in Figures 17 to 22. Figure 28 shows an embodiment in which ball bearings 50 are provided to maintain the clearance between the inertia weight component 20 and the mounting base 10. According to this embodiment, the weight of the inertia weight component 20 which is applied to the vibration absorbing layer 30 can be averaged as in case of the embodiment shown in Figures 1 and 5. In this embodiment, the inside of the housing of the bearing 50 is filled with gel material but the bearing 50 is mainly used to maintain the clearance. Accordingly, the housing of the bearing 50 need not be filled with gel material. The embodiments shown in Figures 29 and 30 are inertia dampers in which the doughnut type disk inertia weight component 20 is respectively accommodated in a space formed by the disk type fitting surfaces 11' and 11' of the mounting base 10 and the vibration absorbing layer 30 is provided between the disk type fitting surfaces 11' and 11' and the fitting surfaces 21' and 21' of the disk type inertia weight component 20. This inertia damper provides the same effect as the inertia damper of the type shown in Figure 7. In the embodiment shown in Figure 30, the vibration absorbing layers 281' and 281' are provided respectively between disks 28 which form the inertia weight component 20, and the vibration is absorbed in the inertia weight component 20 as in the embodiment shown in Figure 6. Hereupon, the weight of said inertia weight component 20 can be adjusted by attaching a spare doughnut type disk 281 to the inertia weight component 20 as shown with the broken line in Figure 23. Such construction as described above is advantageous in that the weight of the inertia damper as a finished product can be adjusted to meet the load torque of the applicable object in actual use. In addition, the skin layer 33 formed on said vibration absorbing layer 30 can be obtained by applying the acetic acid type or oxime type coating agent using silicone resin as the base or the polymer containing SiH or the mixture of catalyst and the polymer containing SiH to the surface of silicone gel. As this coating agent, SH237 Dispersion (product name) which is the mold parting agent made by Toray Silicone Kabushiki Kaisha, SE5001, SH780, SE5002 and SE504 (product name) which are the adhesive agents made by Toray Silicone Kabushiki Kaisha and SCA 101 (product name) which is the bridging booster made by Toray Silicone Kabushiki Kaisha are available.

Claims: An inertia damper comprising a mounting base (10) to be mounted on a rotary shaft (40), a vibration absorbing layer (30) one surface of which is coupled to said mounting base (10) and an inertia weight component (20) which is coupled to the other surface of said vibration absorbing layer (30) and to said mounting base (10) through said vibration absorbing layer (30), characterised in that said vibration absorbing layer (30) comprises a gel material with a penetration value of approximately 50 to 200. An inertia damper in accordance with Claim 1, wherein said vibration absorbing layer (30) is made of a silicone gel material. An inertia damper in accordance with Claim 1 or 2, wherein said mounting base (10) has a shaft hole (12) through which the rotary shaft (40) may be inserted and a circumferential external peripheral surface around said shaft hole (12) as a fitting surface, said inertia weight component (20) being made as an annular disk in the center of which a hole into which said mounting base (10) is loosely fitted is provided with the internal surface of the hole serving as a fitting surface, and said vibration absorbing layer (30) is formed between the fitting surface of said mounting base (10) and the fitting surface of said inertia weight component (20). An inertia damper in accordance with Claim 3, wherein opposed grooves (111,211) are provided at the center of the fitting surface of said mounting base (10) and the center of the fitting surface of said inertia weight component (20) in the circumferential direction of the fitting surfaces, and said vibration absorbing layer (30) is formed to fill the groove. An inertia damper in accordance with Claim 3, wherein at least parts (111',211') of the fitting surface of said mounting base (10) and the fitting surface of said inertia weight component (20) are protruded in the radial direction and these protruded parts are gear-meshed with each other. An inertia damper in accordance with Claim 3, wherein at least one groove (111,211) is provided respectively on the fitting surface of said mounting base (10) and the fitting surface of said inertia weight component (20) and the vibration absorbing layer (30) is provided in said groove. An inertia damper in accordance with Claim 3, wherein said inertia weight component (20) comprises a plurality of annular members (23,24,25) which are concentrically assembled. An inertia damper in accordance with Claim 7, wherein at least one vibration absorbing layer (30,201,201') is provided between said annular members to couple these annular members. An inertia damper in accordance with Claim 3, wherein both circumferential sides (31,31') of the vibration absorbing layer (30) between said mounting base (10) and said inertia weight component (20) are exposed to the outside and a non-tacking skin layer is formed on these exposed parts. An inertia damper in accordance with Claim 3, wherein an engaging means (114,214) for engaging the inertia weight component (20) with the mounting base (10) is provided on one of said mounting base (10) and said inertia weight component (20) to prevent the inertia weight component (20) from movement when said inertia weight component (20) is moved in the axial direction of the rotary shaft. An inertia damper in accordance with Claim 10, wherein a ridge (113,213) which extends in the circumferential direction of the fitting surface is provided on one of the fitting surfaces of said mounting base (10) and said inertia weight component (20) and a groove (114,214) into which said ridge (113,213) is inserted is provided on the other of said fitting surfaces to engage said ridge (113,213) with the groove (114,214). An inertia damper in accordance with Claim 10, wherein a cover (27) is provided on one of said inertia weight component (20) and said mounting base (10), both free ends (271,271') of said cover (27) being extended outside the other of said inertia weight component (20) and said mounting base (10) to be engaged with one of the inertia weight component (20) and the mounting base (10) which is opposed to the free end of the cover (27) serving as the engaging part. An inertia damper in accordance with any preceding claim, wherein an external surface of said vibration absorbing layer (30) is formed as a non-tacking skin layer which is adhered to the fitting surface of said mounting base (10) and the fitting surface of said inertia weight component (20). An inertia damper in accordance with Claim 13, wherein both sides of the skin layers of said vibration absorbing layer (30) are exposed to the outside between said mounting base (10) and said inertia weight component (20). An inertia damper in accordance with Claim 3, wherein ball bearings (50) are provided between said inertia weight component (20) and said mounting base (10) to maintain a clearance between said inertia weight component (20) and said mounting base (10). An inertia damper in accordance with Claim 1 or 2, wherein said mounting base (10) has a shaft hole (12) into which the rotary shaft is inserted and the fitting surface (11') extends in the shape of a disk around said shaft hole as the center in a direction orthogonal to the axis of the rotary shaft, and wherein said inertia weight component (20) has a disk type fitting surface (21') opposed to the disk type fitting surface (11') of said mounting base (10), and said vibration absorbing layer (30) is formed between the fitting surface (11') of said mounting base (10) and the fitting surface (21') of said inertia weight component (20). An inertia damper in accordance with Claim 16, wherein said mounting base (10) is provided at an extreme end of the rotary shaft and a circumferential edge is provided at the outer periphery of the fitting surface whereby the disk type inertia weight component (20) is accommodated in said circumferential edge. An inertia damper in accordance with Claim 16, wherein said mounting base (10) has a space formed by a pair of opposing disk type fitting surfaces (11',11') and the disk type inertia weight component (20) accommodated in said space is coupled to the vibration absorbing layer (30) with both its surfaces in the axial direction as the fitting surfaces (21',21'). An inertia damper in accordance with Claim 18, wherein said disk type inertia weight component (20) is made up by concentrically stacking a plurality of annular disks (20) as an assembly. An inertia damper in accordance with Claim 19, wherein a vibration absorbing layer (281') is provided to couple each adjacent annular disks (28) which comprises said inertia weight component (20), and said vibration absorbing layer (281') provided between adjacent disks is made of a gel material with the penetration value of approximately 50 to 200. An inertia in accordance with claim 1 wherein said vibration absorbing layer comprises a cylindrical member (30) located in grooves (115,215) formed in said mounting base and in said inertia weight component. An inertia damper in accordance with claim 2 wherein said silicone gel material is a compound gel material comprising fine hollow particles.

Inventors: NAKANISHI MOTOYASU
Applicants: KABUSHIKI KAISHA SIGEL
Application year: 1988
Main classification: H02K37
IPC codes: F16F15, H02K37