JPH06159439A - Pulley damper - Google Patents

Abstract

PURPOSE:To provide a low-priced pulley damper which does not produce vibration in the audio-frequency range and which does not become a source of noise by forming the pulley-inertial body of the pulley damper by a material, the Young's modulus of which is sufficiently higher than that of the material of a pulley hub. CONSTITUTION:A pulley damper 10 is loaded on the crank shaft of, for example, a diesel engine to suppress torsional vibration of the crank shaft, and to drive other rotary shafts through belts. On the outside of a pulley hub 12 loaded on the crank shaft and rotating integrally with the crank shaft, a pulley-inertial body 16 is arranged concentrically through a cylindrical rubber member 14. In this case, the pulley hub 12 is formed by a low-priced FC material as before, for example, JIS FC 250. On the other hand, the pulley-inertial body 16 is formed by a FCD material (spherical graphite cast iron), the Young's modulus for which is sufficiently higher than that of the FC material, for example, JIS FCD 700. Thus, the rigidity of the pulley-inertial body 16 is improved to increase the natural frequency, and thus the pulley damper is prevented from becoming a source of noise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is mounted on a rotary shaft such as a crankshaft of a diesel engine for a vehicle to suppress torsional vibration of the rotary shaft, and also to prevent other vibrations through a winding transmission member such as a belt. The present invention relates to a pulley damper that drives a rotating shaft.

[0002]

2. Description of the Related Art A pulley hub fixedly attached to a rotating shaft of a vehicle diesel engine such as a crankshaft where torsional vibrations are generated and rotating integrally with the rotating shaft, and a concentric hub outside the pulley hub via a tubular rubber member. A pulley damper having a pulley inertial body mounted on it is known in the art.

However, in the conventional pulley damper, the pulley inertial body and the pulley hub are made of the same material, generally inexpensive FC material (gray cast iron),
Since the rigidity of the pulley inertial body on the radially outer side is smaller than that of the pulley hub on the radially inner side and the natural frequency thereof is small, the pulley inertial body itself is often in the audible frequency range (approximately 0.
There is a problem that it causes a vibration of 5 K to 2 KHz) and becomes a noise source.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a pulley damper at a low price, which hardly causes vibration in the audible frequency range and therefore does not cause a trouble as a noise source. That is the purpose.

[0005]

To achieve the above object, the present invention provides a pulley inertia member concentrically disposed on the outside of a pulley hub via a cylindrical rubber member. A pulley damper characterized in that the body is made of a material having a Young's modulus larger than that of the material forming the pulley hub.

[0006]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the figure, reference numeral 10 generally indicates a pulley damper. The pulley damper is fixed to a rotating shaft (not shown), for example, a crankshaft of a vehicle diesel engine, and a pulley hub 12 that rotates integrally with the rotating shaft.
2, and a pulley inertia body 16 concentrically arranged via a tubular rubber member 14 on the outside.

In the illustrated case, the cylindrical rubber member 14 includes the inner peripheral surface 16 'of the pulley inertial body 16 and the pulley hub 12.
A rubber member, which is cylindrical in a free state, is press-fitted in an axial direction in an annular space formed between the outer peripheral surface 12 'and the outer peripheral surface 12'. The tubular rubber member 14 is
In order to prevent the pulley damper 10 from slipping out in the axial direction during operation, an outer peripheral surface 12 'of the pulley hub 12 is formed with an arcuate rotary surface 18 protruding outward in the radial direction and an inner peripheral surface of the pulley inertial body 16 is formed. An arcuate rotary surface 20 is formed on the surface 16 ′ and has a shape substantially similar to the arcuate rotary surface 18 and is recessed radially outward. Further, the pulley inertial body 1 is formed.
One or more (three in the illustrated case) pulley grooves 22 are formed on the outer peripheral surface of 6.

Like the conventional pulley damper, the pulley hub 12 is made of an inexpensive FC material such as JIS FC250, while the pulley inertial member 16 is an FCD material (spheroidal graphite cast iron) having a sufficiently higher Young's modulus than the FC material such as JIS F.
It is formed by CD700. Further, as shown in the drawing, the effective thickness x of the pulley inertial body 16 related to the same vibration is set to be larger than the effective thickness x of the pulley hub 12 related to the out-of-plane vibration.

According to the above-mentioned configuration of the present invention, the pulley inertia body 16 which has conventionally been a noise source has a sufficiently larger Young's modulus than the pulley hub 12 usually made of FC material.
Made of FCV material or FCV material, it has inherently high rigidity, and has a sufficiently large natural frequency as compared with a conventional pulley inertial body (made of FC material) of the same size, so that a rotating shaft such as a vehicle engine can be used. Of the crankshaft can be set to a rotational speed region outside the normal rotational speed region or at least within the normal rotational speed region where the operating frequency is low, and the pulley inertial body 16 can be effectively avoided as a noise source. .

Further, as described above, the pulley inertial body 16 is made of a material having a large Young's modulus, and the effective thickness y thereof is set to be larger than the corresponding effective thickness x of the pulley hub 12. It is possible to more reliably prevent the pulley inertial body from becoming a noise source by further increasing the rigidity and increasing the natural frequency.

Since the pulley hub 12 is naturally smaller in diameter than the pulley inertial body 16, even if it is made of an FC material having a small Young's modulus and a low cost, and the effective wall thickness x is set to be sufficiently small, the vibration of the pulley hub 12 will occur. Can be effectively suppressed. This means that, for example, the pulley damper 10 described above is used.
Is mounted on the crankshaft of a vehicle diesel engine, it is allowed to set the effective wall thickness y of the pulley inertial body 16 to a sufficiently large value within the range of the space (particularly the outer diameter) allowed for the pulley damper. It is a thing.

[0012]

As described above, in the pulley damper according to the present invention, the pulley inertia body is concentrically arranged on the outer side of the pulley hub via the cylindrical rubber member. It is possible to provide an inexpensive pulley damper capable of effectively preventing itself from becoming a noise source, characterized by being formed of a material having a Young's modulus higher than that of the material forming the pulley hub. There are advantages.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a pulley damper according to an embodiment of the present invention.

[Explanation of symbols]

 10 Pulley Damper 12 Pulley Hub 14 Cylindrical Rubber Member 16 Pulley Inertia

Claims (1)

[Claims] 1. A pulley hub concentrically arranged on the outside of a pulley hub via a tubular rubber member, wherein the pulley inertial body has a Young's modulus larger than that of a material forming the pulley hub. Pulley damper, characterized in that it is formed of a material having an index