JPH02292558A - Damper pulley - Google Patents

Abstract

PURPOSE:To substantially improve a degree of design freedom with the cost and weight reduced by providing a spring constant-changing means, positioned in an intermediate part in the diametric direction of a rubber-state elastic unit, with a predetermined space in a peripheral direction. CONSTITUTION:An inertia means 20 is mounted to peripheral surfaces of a rim part 13 through a rubber-state elastic unit 30. A spring constant-changing means 31 is positioned in an intermediate part in a diametric direction of the before described rubber-state elastic unit 30 and provided in a peripheral direction with a predetermined space. A spring constant of the rubber-state elastic unit 30, which arises from its distortion, can be changed by the spring constant- changing means 31. As a result, performance of a degree equal to a plurality of inertia masses is obtained by a single inertia mass. Thus by reducing the cost and weight, a degree of design freedom can be substantially improved.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) This invention is attached to a rotating shaft, transmits the rotational power of the rotating shaft, and rotates by a combination of an inertia mass and a rubber-like elastic body. This relates to a damper pulley that reduces vibrations from the shaft.

(Prior art) A damper booley is attached to the shaft end of a rotating shaft, such as the crankshaft of an automobile engine, and is used as a pulley to transmit power to auxiliary equipment such as an air conditioner compressor or power steering bomb. The vibration of the crankshaft inside can be reduced by the characteristics determined by the mass of the inertia mass and the spring constant of the rubber-like elastic body.

By the way, as engines have become higher in output and speed in recent years, the torsion angle of the crankshaft has increased, and with a damper booley equipped with a single inertia mass,
Crankshaft vibration cannot be sufficiently reduced. Therefore, in order to solve this problem, a damper booley with a plurality of inanyamas attached has recently been used. However, when a plurality of inertia masses are provided in this way, there is a drawback that the cost increases and the weight increases. In particular, the increase in weight has been a problem in the recent automatic military, where there is a strong demand for weight reduction.

This invention solves the above-mentioned drawbacks of the prior art, and its purpose is to provide a damper booley in which one inertia mass can provide the same performance as a plurality of inertia masses. be.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a damper pulley in which an inertia mass is attached to the outer circumferential surface of a rim portion via a rubber-like elastic body. It is characterized in that spring constant changing means are provided at predetermined intervals in the circumferential direction and are located at a radially intermediate portion.

(Function) The spring constant changing means can change the spring constant of the rubber-like elastic body due to distortion of the rubber-like elastic body. As a result, one inertia mass can provide the same performance as a plurality of inertia masses. Therefore, an inexpensive and lightweight damper pulley can be provided.

(Example) The present invention will be described below based on embodiments shown in the drawings.

1 to 4 show an embodiment of the present invention, FIG. 1 is a vertical cross-sectional side view of the damper pulley, FIG. 2 is an explanatory view of the ■-■ arrows in FIG. FIG. 2 is an enlarged explanatory view of part A in FIG. 2, and FIG. 4 is a damper frequency-rubber strain diagram illustrating the performance of the damper pulley.

In the figure, E denotes a damper pulley of the present invention, in which an inertia mass 20 is attached to the outer peripheral surface of a rim portion 13 via a rubber-like elastic body 30.

In this invention, in particular, the rubber-like elastic body 30
A spring constant changing means 31 is provided at a predetermined interval in the circumferential direction at a radially intermediate portion of the spring.

To explain the structure of the present invention in more detail below, the damper pulley E includes a /-b 10, an inertia mass 20, a rubber-like elastic body 30, and a pressure ring 40. The hub 10 consists of a boss portion 11 and a rim portion 13 formed radially outward of the boss portion 11 via a web portion 12, and the boss portion 11 is connected to a rotating shaft, such as the shaft of a crankshaft of an automobile engine. Fixed at the end. Rim part 1
3 is formed into a substantially cylindrical shape and is disposed concentrically with the boss portion 11, and in this embodiment, a square groove, for example, a polygon groove 13a, is carved over the entire circumference in one half of its outer peripheral surface. The inertia mass 20 is formed into a substantially ring shape, and the boss portion 1-
1, and this inertia mass 20
A rubber-like elastic body 30 is vulcanized and welded between the inner peripheral surface of the pressure ring 40 and the outer peripheral surface of the pressure ring 40. The inner circumferential surface of the presser ring 40 is press-fitted into the other half of the outer circumferential surface of the rim portion 13.

Further, in this embodiment, a V-groove, for example, a round groove 20a, is formed on the outer peripheral surface of the inertia mass 20 over the entire circumference.

The slit 3 is a means for changing the spring constant of the rubber-like elastic body 30
], as shown in FIGS. 2 and 3, is approximately U-shaped when viewed from the front and is formed to penetrate in the axial direction of the boss portion IL;
They are located at the radially intermediate portion of the rubber-like elastic body 30 and are arranged at predetermined intervals in the circumferential direction, for example, in alternating directions.

Next, the operation of the above embodiment will be explained.

The damper pulley E is designed to reduce vibration by converting torsional vibration generated around the rotation center line of the crankshaft during engine rotation into deformation of the rubber-like elastic body 30. This deformation of the rubber-like elastic body 30, so-called rubber distortion, increases as the engine output increases and the rotation speed increases.

When the engine speed is low and the rubber strain is below a predetermined value (E%), there is a gap in the radially protruding portion 31a of the slit 31, and this creates a gap in the portion divided by the slit 31 (shaded). Only the rubber-like elastic body 30 in the parts other than the parts) is acting. As a result, the spring constant becomes small, and thereby the natural frequency of the damper pulley E can be set low as shown by curve a in FIG. 4.

Note that the natural frequency shown by this curve a is set to be slightly lower than the natural frequency of a normal Gumper Boully.

When the rotational speed of the engine increases and the rubber strain exceeds a predetermined value (E%), the gap in the slit 31 portion 31a disappears, and the rubber-like elastic body 30 comes to act over the entire area. As a result, the spring constant becomes large, and thereby the natural frequency of the damper booley E can be set low as shown by curve b in FIG. 4.

Figure 5 is an engine speed-crankshaft torsion angle diagram explaining the performance of the damper booley when the engine is installed.
), and curve B shows the performance when the Dunbar frequency is the fourth
The performance in the case of curve (b) in the figure is shown. Also, curve C
shows the performance when curves (a) and (b) are combined.

Figure 6 is a diagram showing the engine speed vs. crankshaft torsion angle diagram to compare and explain the performance of the damper pulley of this invention and the conventional damper pulley (one inertia mass) when the engine is installed. The curve E shows the performance of the damper pulley E of this invention, and the curve E shows the performance of the conventional damper pulley.

As described above, according to the present invention, by providing the slits 1 and 31, which are spring constant changing means, in the rubber-like elastic body 30, a damper pulley E having two different natural frequencies can be obtained. With one inertia mass 20, performance comparable to that of a conventional damper pulley having two inertia masses can be obtained. Furthermore, the natural frequency of the damper pulley E can be determined by appropriately selecting the shape of the slit 31, the arrangement interval of the slit 31, etc.
By changing the spring constant of 0, it is possible to set the most appropriate value according to the specifications of the spring.

FIGS. 7(a) and 7(b) are explanatory diagrams showing a modification of the spring constant changing hair stage 31. FIG. Slipper I-3 shown in Figure 7(a)
1A, a convex portion 3lb is formed in the circumferentially intermediate portion of the slit 31 shown in FIGS. 2 and 3, and the slit 3113 shown in FIG. 7Cb) is formed in a V-shape. The action of these slits 31A and 31B is that of slits 1 and 31.
This is the same as , and its explanation will be omitted.

〔Effect of the invention〕

As explained above, according to the damper booley of the present invention, the spring constant of the rubber-like elastic body can be changed due to the distortion of the rubber-like elastic body. As a result, one inertia mass can provide the same performance as a plurality of inertia masses.

Therefore, it is possible to reduce costs, reduce weight 2, and furthermore, by appropriately selecting the spring constant changing means, it is possible to provide an appropriate damper pulley that corresponds to various specifications, increasing the degree of freedom in design. can be significantly improved.

[Brief explanation of drawings]

1 to 4 show an embodiment of the damper pulley of the present invention. Figure 3 is an enlarged explanatory view of part A in Figure 2, Figure 4 is a damper frequency vs. rubber strain diagram to explain the performance of the damper pulley, and Figure 5 is an engine rotation diagram to explain the performance of the damper pulley when the engine is installed. Number 1 Crankshaft torsion angle diagram, Figure 6 is an engine rotation speed vs. crankshaft torsion angle diagram to explain the performance of the damper booley of this invention and the conventional product (Sugruinershamas) when the engine is installed. , FIGS. 7(a) and 7(b) are explanatory front views showing a modification of the spring constant changing means. E...Dunbar pulley 10...Hub 13...Rim part 20...Inertia mass 30...Rubber-like elastic body 31.31A, 31B...Spring constant changing means (slit) Agent Patent attorney 3 Kazuho Yoshihide 1 Figure 111 Engine rotation @ (rDm) i5 Figure? Engine rotation speed (rDm) 61Xl 73rd section Dunbar frequency (Hz) 31b 31A 2Q Figure 7 (b)

Claims (1)

[Claims] A damper pulley in which an inertia mass is attached to the outer peripheral surface of a rim portion via a rubber-like elastic body, and the spring constant is changed at a predetermined interval in the circumferential direction by positioning the inertia mass at a radially intermediate portion of the rubber-like elastic body. A damper pulley characterized by having a means.