JPH0366968A - Damper pulley - Google Patents

Abstract

PURPOSE:To improve the durability of a damper pulley itself by press-fitting a partition member made of a circular ring formed rubber thin film between the radially corresponding peripheral surfaces of a damper mass and a pulley main body so as to form a closed space between the partition member and the connecting part of the pulley main body and sealing a viscous fluid into this closed space. CONSTITUTION:A circular ring formed elastic rubber body 32 is interposed between the opposed peripheral faces of the fixing part 30 of a cylinder bracket 26 and the connecting part of a pulley main body 12, and the bracket 26 is cantilever-supported to the pulley main body 12 through the elastic rubber body 32. A main body cylinder fitting 28 and a ring member 34 are vulcanization-adhered respectively to the outer peripheral surface and inner peripheral surface of a circular ring formed rubber thin film 36. Accordingly, a closed ring space 38 is partitioned between the main body cylinder bracket 28 and the connecting part 20 of the pulley main body 20, and a viscous fluid of high kinematic viscosity is sealed thereinto. High damping force to the displacement of a damper mass 24 is displayed on the basis of the hearing stress of the viscous fluid, and the durability of the elastic rubber body 32 is thereby improved remarkably.

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a damper pulley that is attached to a rotating shaft such as a crankshaft of an internal combustion engine to absorb and reduce vibrations in the rotating shaft, and particularly relates to a damper mechanism thereof. The present invention relates to a damper pulley that can improve the durability of the damper pulley.

(Background Art) When the crankshaft of an internal combustion engine rotates, complex vibrations and noise are generated in the crankshaft in the bending and torsional directions due to torque fluctuations, etc. Problems such as breakage may occur. Therefore, damper pulleys that are equipped with a damper mechanism, a so-called dynamic vibration absorber, to absorb and reduce such vibrations have been used as pulleys attached to the crankshaft.

By the way, as is well known, such a damper mechanism has an annular mass member disposed concentrically with a pulley body that is attached to a rotating shaft and rotated integrally with the mass member. It has a structure in which it is elastically supported by a rubber elastic body interposed between the surface facing the pulley body.

Then, the mass, spring constant, and damping coefficient are tuned so that an effective vibration damping effect can be exhibited, and the resonance frequency of the vibration system is set to match the vibration frequency of the crankshaft for the purpose of vibration isolation. It is being done.

However, in the damper mechanism of such a conventional structure, the spring constant and damping coefficient are solely based on the elasticity and damping of the rubber elastic body, and therefore, the rubber elastic body is subject to complex deformation due to repeated loads. As a result, the durability of the rubber elastic body is significantly impaired, which in turn reduces the durability of the damper pulley.

In particular, in dual-type damper pulleys that are designed to absorb not only vibrations in the torsional direction but also vibrations in the bending direction, the deformation caused by the load on the rubber becomes even more complex, and therefore the durability The decline will become even more significant.

-i, the damper mechanism in such a dual type damper pulley is constructed by connecting a mass member and a pulley body between circumferential surfaces facing each other in the axial direction, and the mass member is formed by a rubber elastic body. Although the crankshaft is designed to have an elastic end supported by a cantilever structure, the vibrations generated by the crankshaft include vibrations in the bending direction and vibrations in the torsional direction, and the vibration frequency in the bending direction (generally 250 〜350Hz) is lower than the vibration frequency in the torsional direction (generally around 300~400Hz).
In order to set the resonant frequency in the bending direction lower than the resonant frequency in the torsional direction, as disclosed in Publication No. A structure has been proposed in which the main part of the damper mass is located substantially inward in the radial direction of the pulley with respect to the connecting part made of the rubber elastic body by disposing the damper mass outwardly. .

In such a damper mechanism, since the spring constant for bending shear in the rubber elastic body is small and the weight of the damper mass is large, the rubber elastic body easily undergoes deformation in the bending direction. At the time of resonance, the amount of deformation of the rubber elastic body may become excessive, resulting in a decrease in the durability of the negative layer.

(Problem to be solved) Under such circumstances, the problem to be solved by the present invention is to
By suppressing the deformation caused in the rubber elastic body without substantially impairing the vibration damping properties exhibited by the rubber elastic body,
The objective is to improve the durability of the rubber elastic body and, in turn, to improve the durability of the damper pulley.

(Solution Means) In order to solve the above problems, the present invention includes a boss portion attached to a rotating shaft, a cylindrical portion located on the radially outer side of the boss portion, and a cylindrical portion between the boss portion and the cylindrical portion. A substantially cylindrical damper mass is concentrically disposed within the inner space of the cylindrical portion of the pulley body having a connection portion connecting the In a damper pulley having a structure in which corresponding circumferential surfaces are connected by a rubber elastic body, first and second cylindrical members are located concentrically and a circle is provided between the first and second members. A partition member made of an annular rubber thin film is press-fitted between circumferential surfaces corresponding to the radial direction between the damper mass and the pulley main body, thereby creating a sealed space between the connecting portion of the pulley main body and the connecting portion of the pulley main body. A predetermined highly viscous fluid is sealed within the space.

(Examples) Hereinafter, in order to clarify the present invention more specifically, examples of the present invention will be described in detail with reference to the drawings.

First, FIG. 1 shows a damper pulley 10 having a structure according to the present invention. In such a figure, 12
1 is a pulley body which is attached to a crankshaft of a predetermined internal combustion engine lever (not shown) and rotated together with the crankshaft, and includes a small-diameter cylindrical boss portion 16 and a predetermined distance radially outward from the boss portion 16. A cylindrical part 18 having a large number of V grooves 17 formed on the outer circumferential surface of the cylindrical part 18 and the outer circumferential surface of the boss part 16 and the cylindrical part 1 are spaced apart from each other and are concentrically positioned.
8 and a connecting portion 20 that extends in the radial direction in a disk shape and connects the inner circumferential surfaces of the connecting portions 8 and 8 to each other.

The pulley main body 12 is attached to the crankshaft of the internal combustion engine at the boss portion 16, while a predetermined V-belt is wrapped around the outer peripheral surface of the cylindrical portion 18, so that the pulley body 12 is attached to the crankshaft of the internal combustion engine. It is designed to function as a V-belt drive pulley that transmits the driving force of the V-belt to a predetermined subsequent member.

Further, the inside of the cylindrical portion 18 in the pulley body 12 is partitioned in the direction perpendicular to the axis by the connecting portion 20.
By being provided at a position biased toward one end in the axial direction, one side of the cylindrical portion 18 partitioned by the connecting portion 20 has a relatively large mass accommodating space 22.
It is formed as.

In the mass accommodation space 22, a damper mass 24 having an approximately cylindrical shape as a whole is disposed in a housed state.

Here, the damper mass 24 is doubled at its radial center, with a mounting cylinder fitting 26 as a mounting portion located on the radially outer side, and a mass body portion ( Body cylindrical fitting 2 as mass main body
It is composed of two cylindrical bodies consisting of 8. The mounting cylindrical fitting 26 has a thin cylindrical shape as a whole, and is integrally provided with an outer flange-shaped fixing portion 30 that projects radially outward with a predetermined width at one axial end thereof. As shown in FIG. 2, in the mounting tube fitting 26, the axial end surface of the fixed portion 30 faces the connecting portion 20 of the pulley body 12 at a predetermined distance. It is arranged in the mass accommodation space 22 in this state.

Further, between the opposing circumferential surfaces of the fixing part 30 of the mounting tube fitting 26 and the connecting part 20 of the pulley body 12, an annular rubber elastic body having an inner and outer diameter between the fixing part 30 and the groove is provided. 3
2 is interposed, and the corresponding circumferential surfaces of the fixing portion 30 and the connecting portion 20 are integrally vulcanized and bonded to both end surfaces of the rubber elastic body 32 in the axial direction. ing. As a result, the mounting fitting 26 is supported in a cantilevered manner with respect to the pulley main body 12 via the rubber elastic body 32. Then, the main body cylindrical fitting 28 is press-fitted and fixed to the mounting cylindrical fitting 26 supported by the pulley main body 12 via the rubber elastic body 32, thereby forming the damper mass 24. This constitutes a vibration system that can function as a dynamic vibration absorber (damper mechanism).

That is, in this embodiment, the main body cylindrical fitting 28 forming the mass body (main body) of the damper mass 24 is connected to the rubber elastic body 3.
2, the damper mass 24 as a whole is located more inward in the radial direction of the pulley body 12 than the connecting portion by the rubber elastic body 32. The resonant frequency in the bending direction can be set lower than the resonant frequency in the torsional direction. Therefore, the frequency of vibrations in the bending direction and torsional direction inputted from the crankshaft can be well tuned, and excellent vibration absorption can be achieved.

By the way, the main body cylindrical fitting 28 has a predetermined distance on its inner circumferential surface at one end in the axial direction, in other words, at a portion facing the boss portion 16 of the pulley main body 12 at a predetermined distance. Thin cylindrical ring members 34 are concentrically connected with their outer peripheral surfaces facing each other.

That is, the main body cylindrical fitting 28 and the ring member 34 are connected in a double-cylindrical shape by being vulcanized and bonded to the outer and inner circumferential surfaces of an annular thin rubber film 36 extending in the radial direction, respectively. It is being done. Since the inner diameter of the ring member 34 is slightly smaller than the outer diameter of the boss portion 16, when the main body cylindrical fitting 28 is press-fitted into the inner circumferential surface of the mounting cylindrical fitting 26, it is possible to simultaneously Since the ring member 34 is press-fitted into the outer peripheral surface of the boss portion 16, a sealed annular space 38 with the connecting portion 20 of the pulley body 12 is formed at both ends. be.

As is clear from this, in this embodiment, the main body cylindrical fitting 28 also serves as the first member, and constitutes the partition member 40 together with the ring member 34 and the rubber thin film 36, which are the second members. .

Note that since the rubber thin film 36 constituting the partition member 40 is set to be sufficiently thin, the elasticity of the rubber thin film 36 does not interfere with the spring constant of the rubber elastic body 32, and the rubber The resonant frequency set by the elastic body 32 can be maintained well, and there is virtually no possibility that the damping effect will be impaired.

A highly viscous fluid with high kinematic viscosity is sealed in the annular space 38 having both bottoms. In order to effectively obtain the shear stress described below, such a high viscosity fluid generally has a kinematic viscosity of 100,000 centistics or more, preferably 200,000 centistics or more, and among these, it is desirable to have a kinematic viscosity of 100,000 centistics or more, preferably 200,000 centistics or more. Silicone oil or the like, which exhibits little viscosity change, is preferably used.

In addition, to enclose such a highly viscous fluid in the annular space, the partition members (28, 34, 36) are placed between the damper mass 24 and the pulley body 12 (more precisely, the mounting tube fitting 2
6 and the boss portion 16), it is also possible to press fit into the fluid by performing the press fit into the fluid, but with this method, the fluid attached to the outer surface is Since removal is required, for example, a predetermined amount of fluid is injected into the annular space 38 in advance, and then the partition members (28, 34, 36) are assembled, or the partition members (28, 34, 36) are assembled. After that, it is desirable to carry out the injection by a method such as injection through a separately provided injection hole.

That is, the damper battery 10 having such a configuration
In this case, when the vibration input from the crankshaft causes a displacement (vibration) in the bending or torsional direction to the damper mass 24, the vibration is generated based on the elasticity and damping of the rubber elastic body 32, as in the conventional case. As a result, such vibrations are absorbed, but in addition, since a flow is induced in the high viscosity fluid sealed in the annular space 38, the velocity gradient of the flow is approximately proportional to the velocity gradient of the flow. A shearing stress is generated, and based on this shearing stress, a high damping force against the displacement of the damper mass 24 can be exerted.

In short, in such a damper mass 2410, in addition to the damping caused by the rubber elastic body 32, damping can be exerted due to the viscous resistance of the viscous fluid, and the amount of deformation of the rubber elastic body 32 is suppressed accordingly. Further, excessive deformation can be effectively prevented, and the durability of the rubber elastic body 32 can be significantly improved.

The damping force exerted based on the shear shear stress of the viscous fluid depends on the viscosity of the viscous fluid, the area of the damper mass 24 that receives the shear stress of the viscous fluid, or the shear shear stress of the viscous fluid. Tuning can be performed by adjusting the size of the gap between the damper mass 24 and the inner surface of the annular space 38, where this occurs.

Although the embodiments of the present invention have been described in detail above, these are literal illustrations, and the present invention is not to be construed as being limited only to these specific examples.

For example, in the embodiment described above, the damper mass 24 (more precisely, the mounting cylindrical fitting 26) and the pulley body 12 are connected by the rubber elastic body 32 at the circumferential surfaces facing each other in the axial direction, thereby forming the vibration system. However, the damper mass 24 and the pulley main body 12 may be connected in the radial direction by connecting their outer circumferential surface and inner circumferential surface, or by connecting their inner circumferential surface and outer circumferential surface. Needless to say.

Furthermore, in the embodiment described above, the first member constituting the partition member 40 was also served by the main body cylindrical fitting 28;
Needless to say, the partition member 40 can be configured as a separate member, and in addition to being press-fitted between the outer circumferential surface of the boss portion 16 and the inner circumferential surface of the damper mass 24, as explained in the above-mentioned embodiment, Of course, it is also possible to press fit between the inner circumferential surface of the cylindrical portion 18 and the outer circumferential surface of the damper mass 24.

In addition, although not listed, the present invention can be implemented in embodiments with various changes, modifications, improvements, etc. added based on the knowledge of those skilled in the art, and such embodiments are not limited to the present invention. It goes without saying that any of these are included within the scope of the present invention as long as they do not depart from the spirit of the invention.

(Effects of the Invention) As is clear from the above detailed description, in the damper pulley according to the present invention, the damping force in the damper mechanism is generated not only by the rubber elastic body but also by the shear stress of the high viscosity fluid. Since the rubber elastic body can be obtained with This can in turn lead to an improvement in the durability of the damper pulley itself.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a damper pulley according to the present invention, and FIG. 2 is a longitudinal sectional view showing the damper pulley in a state before the partition member is press-fitted. 10: Damper pulley 12: Pulley body 16: Boss portion 18: Cylindrical portion 20; Connection portion 24: Damper mass 26: Mounting cylindrical fitting 28 Two body cylindrical fittings (first member) 32: Rubber elastic body 34: Ring member (first member) (Second member) 36: Rubber thin film 38: Annular space 40: Partition member

Claims (1)

[Claims] For a pulley body having a boss portion attached to a rotating shaft, a cylindrical portion located on the radially outer side of the boss portion, and a connecting portion connecting the boss portion and the cylindrical portion, such A structure in which a substantially cylindrical damper mass is arranged concentrically so as to be located within the inner space of the cylindrical part, and the corresponding peripheral surfaces of the damper mass and the pulley body are connected by a rubber elastic body. In the damper pulley, a partition member consisting of concentrically located cylindrical first and second members and an annular rubber thin film provided between the first and second members is connected to the damper mass. Press fit between circumferential surfaces corresponding to the pulley body in the radial direction to form a sealed space between the connecting portion of the pulley body and seal a predetermined high viscosity fluid within the space. A damper pulley that is characterized by its unique features.