JPH10103409A - Torsional damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably maintain a dynamic damping effect for a long period without generating circumferential slippage on a pressure welding surface between an elastomer and either a hub or a mass. SOLUTION: A partially raised surface 12 and a recessed surface 21 are formed circumferentially as several pairs on both an outer surface 11a of a hub 10 and an inner surface 20a of a mass 20 to constitute a convolution part of the elastomer 30. In this case, the outer surface 11a forms a pressure contact surface between the elastomer 30 and the hub 10, and also the inner surface 20a forms a pressure welding surface between the elastomer 30 and the mass 20. For this reason, a torque is produced between the hub 10 and the mass 20, and then a circumferential compressive force is applied to the elastomer 30 between the raised surface 12 and the recessed surface 21. This compressive force effectively prevents circumferential slippage on the pressure welding surface between the elastomer 30 and either the hub 10 or the mass 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torsional damper for mainly absorbing torsional vibration of a crankshaft of an engine, and in particular, an elastomer is press-fitted between opposed peripheral surfaces of a hub and a mass body around the hub. The present invention relates to a torsional damper having a combined structure.

[0002]

2. Description of the Related Art An engine of an automobile or the like is driven while repeating the steps of intake, compression, explosion (expansion) and exhaust, and reciprocating motion of a piston is converted into rotary motion by a crankshaft. The crankshaft generates torsional vibration (rotational vibration) with the rotation. In order to effectively absorb such torsional vibration, a torsional damper is mounted on the shaft end of the crankshaft protruding from the crankcase of the engine.

As shown in FIGS. 5 and 6, a torsion damper basically includes a hub 1 attached to a shaft end of a crankshaft and an annular mass body 2 arranged concentrically around the hub. It has a structure elastically connected via an elastomer 3, and the resonance system including the mass body 2 and the elastomer 3 has different phase angles with respect to the vibration displacement of the torsional vibration of the crankshaft input through the hub 1. By resonating, it exerts a vibration damping function.

The torsional damper illustrated in FIGS. 5 and 6 is called a fitting type torsional damper, that is, an elastomer 3 previously formed into an annular shape as shown by a two-dot chain line in FIG. Are press-fitted between the outer peripheral surface of the mass body 2 and the inner peripheral surface of the mass body 2. Conventionally, in such a fitting type torsional damper, as shown by a broken line in FIG. 5 and a sectional view of FIG. Annular ridge 1
a is formed on the inner peripheral surface of the mass body 2.
By forming a circumferentially continuous annular concave portion 2a having a cross-sectional shape corresponding to the above, a meandering convolution portion 3a is formed in the elastomer 3, and the elastomer 3, the hub 1, and the mass body 2 are fitted to each other. The unity is maintained by the combination.

[0005]

In the conventional fitting type torsional damper, when the elastomer 3 is press-fitted between the hub 1 and the mass body 2 in a highly compressed state, the compression reaction force of the elastomer 3 causes the hub 1 and the hub 1 to move. Since a large frictional force is applied to the pressure contact surface with the mass body 2 and the mutual holding force of the parts 1 to 3 depends on this frictional force, the following problems are pointed out. (1) When an excessive torque is generated between the hub 1 and the mass body 2, a circumferential slip occurs on the mutually pressed surfaces of the hub 1 and the elastomer 3 or on the mutually pressed surfaces of the elastomer 3 and the mass body 2. Sometimes. (2) If the compression set (set) of the elastomer 3 increases due to long-term use, and the frictional force against the hub 1 and the mass body 2 decreases, a slip in the circumferential direction occurs even with a relatively small torque, and effective dynamic There is a possibility that the effective vibration absorption effect cannot be exhibited. (3) In order to apply a required frictional force to the press-contact surface between the elastomer 3 and the hub 1 and the mass body 2, it is necessary to press-fit the elastomer 3 in a highly compressed state, and therefore the press-fit resistance is large.

The present invention has been made in view of the above circumstances, and a technical problem thereof is that a slip does not occur on a press contact surface between an elastomer and a hub or a mass body.
The purpose is to maintain a stable dynamic vibration absorbing effect for a long period of time.

[0007]

Means for Solving the Problems As means for effectively solving the above-mentioned technical problems, a torsional damper according to the present invention has an elastomer between an outer peripheral surface of a hub and an inner peripheral surface of a mass body. In the torsion damper press-fitted, partial raised surfaces are formed at a plurality of positions in the circumferential direction on one of the outer peripheral surface of the hub and the inner peripheral surface of the mass body,
On the other hand, a partial concave surface corresponding to each of the raised surfaces is formed.

According to the present invention, the corresponding raised surface and concave surface formed on the outer peripheral surface of the hub and the inner peripheral surface of the mass body, which are the pressure contact surfaces with the elastomer, constitute the convolution portion for the elastomer. Are not continuous with each other, but are partially formed at a plurality of positions in the circumferential direction. Therefore, when torque is generated between the hub and the mass body, the elastomer is formed between the raised surface and the concave surface. Is given a compressive force in the circumferential direction. The compression force effectively prevents circumferential slip at the pressure contact surface between the elastomer and the hub or the mass body.

The outer peripheral surface of the hub and the inner peripheral surface of the mass body are formed by pressing the elastomer between the hub and the mass body by making cylindrical portions between the raised surfaces and the concave surfaces. When assembling the torsional damper, the press-fitting operation of the elastomer can be easily performed.

[0010]

FIG. 1 is a partially omitted front view showing a preferred embodiment of a torsional damper according to the present invention. FIG. 2 is a sectional view taken along the line X--O in FIG. FIG. 3 is a cross-sectional view taken along the line YO. That is, the torsion damper according to this embodiment is concentrically disposed on the outer peripheral side of the outer diameter cylindrical portion 11 of the hub 10 attached to the shaft end (not shown) of the engine crankshaft in the shaft hole 13. Annular mass body 20, outer peripheral surface 11 a of outer diameter cylindrical portion 11 and mass body 20
And an annular elastomer 30 which is press-fitted to the inner peripheral surface 20a.

On the outer peripheral surface 11a of the outer diameter cylindrical portion 11 of the hub 10, partial raised surfaces 12 are formed at intervals of 90 ° in the circumferential direction. The concave surface 21 having a shape corresponding to the raised surface 12 also has a circumferential direction 90.
° formed at intervals. Therefore, the elastomer 30 fitted between the outer peripheral surface 11a of the outer diameter cylindrical portion 11 of the hub 10 and the inner peripheral surface 20a of the mass body 20, as shown in FIG. A convolution portion 31 gently undulating in the radial direction is formed between them, and the other portions have a simple cylindrical surface shape as shown in FIG.

Note that the outer diameter of each raised surface 12 is smaller than the inner diameter of the mass body 20 in order to arrange the hub 10 and the mass body 20 concentrically with each other.

The torsion damper having the above structure is rotated together with the crankshaft of the engine, and mainly damps the torsional vibration of the crankshaft by the dynamic vibration absorbing action of the resonance system including the mass body 20 and the elastomer 30. is there. The dynamic vibration absorbing action is such that while rotating in a fixed direction together with the crankshaft, the torsional vibration input through the hub 10 in a predetermined frequency range causes the resonance system to resonate with the torsional vibration with a phase difference. 1
It is exerted by an operation such that the mass body 20 is repeatedly displaced relatively in the torsional direction with respect to zero.

The cross-sectional shape of the convolution section 31 cut along a plane passing through the axis is substantially similar to the cross-sectional shape of the convolution section according to the prior art shown in FIG. And mass body 20
Are effectively regulated relative to each other in the axial direction, and the integrity of each other is maintained.

Here, the torque generated between the hub 10 and the mass body 20 due to the above-described dynamic vibration absorbing operation and the like,
As shown in FIG. 4, in the process in which the mass body 20 is relatively displaced in the direction of the arrow A with respect to the hub 10, the elastomer 30 has an outer peripheral surface 11 a of the hub 10 and an inner peripheral surface 20 a of the mass body 20. Shear deformation occurs in the area of the surface,
In the non-cylindrical convolution part 31, the hub 10
A portion 31a between the raised surface 12 on the side and the concave surface 21 which is displaced as shown by a dashed line in the figure undergoes compression deformation. Therefore, the slip torque is locally increased by the compression reaction force generated in the compression deformed portion 31a.
0 and the pressure contact surface of the elastomer 30 or the elastomer 30
It is possible to effectively prevent a circumferential slip from occurring between the pressure contact surfaces of the and the mass body 20.

Further, even if permanent compression strain occurs in the elastomer 30 over time due to long-term use of the torsion damper, for example, the mass body 20 is displaced relative to the hub 10 in the direction of arrow A in FIG. By doing so, the compression force generated in the convolution part 31 (31a) hardly decreases. Therefore, it is possible to prevent the slip from occurring even with a relatively small torque due to the permanent compression strain of the elastomer 30.

When assembling the torsion damper of the above embodiment, the hub 10 and the mass body 20 are positioned concentrically and formed between the outer peripheral surface 11a of the hub 10 and the inner peripheral surface 20a of the mass body 20. The elastomer 30 preliminarily annularly vulcanized and formed is pressed into the annular space to be formed via a predetermined jig. In the process of this press-fitting, the elastomer 30 becomes the raised surface 1
2 and the concavity formed by the concave surface 21, but since this convolution with a large press-fit resistance is not formed continuously over the entire circumference, the convolution is continuously formed in the circumferential direction as in the prior art. The press-fitting resistance is smaller than that having the volute part, so that the press-fitting operation of the elastomer 30 is facilitated.

Further, according to the torsion damper of this embodiment, the circumferential slip on the pressure contact surface between the hub 10 and the elastomer 30 or the pressure contact surface between the elastomer 30 and the mass body 20 can be reduced by compressing the elastomer 30 in the radially high compression state. Since the prevention is not made only by the compression reaction force due to the press-fitting, the radial compression amount of the elastomer 30 at the time of the press-fitting can be reduced. Therefore, the press-fitting work of the elastomer 30 can be facilitated by this, and the permanent compression set of the elastomer 30 is reduced by the decrease in the amount of radial compression, so that the change over time in the vibration absorption characteristics can be suppressed. it can.

The present invention is not construed as being limited to the illustrated embodiment. For example, raised surface 12
The arrangement of the convolution part 31 by the concave surface 21 and
Not only at 90 ° intervals (four equally spaced) in the circumferential direction as shown
120 ° interval (tri-level) or 60 ° interval (hex-level)
Etc. can be arbitrarily set. Also, since the pressure contact surface of the hub 10 with the elastomer 30 is the outer peripheral surface of the outer cylindrical portion 11, the raised surface 12 is formed on the outer cylindrical portion 11. However, depending on the shape and material of the hub 10, By forming a raised surface on the inner peripheral surface of the mass body 20 and forming a concave portion on the outer peripheral surface of the hub 10, a convolution portion having a shape opposite to the radial direction of the illustrated embodiment is formed. You may.

[0020]

According to the present invention, the following effects can be realized. (1) By forming the raised surface and the concave surface constituting the convolution portion for the elastomer at predetermined intervals in the circumferential direction, circumferential slip between the elastomer and the hub or the mass body is effectively prevented. (2) The convolution prevents the elastomer from slipping in the circumferential direction between the hub and the mass body.Even if compression set occurs in the elastomer, the slip torque does not decrease and stable performance is maintained for a long time. You. (3) Since the portion between the convolution portions has a cylindrical surface shape, during the assembly of the torsional damper, there is little resistance to press-in of the elastomer by the convolution portion, and the assembly can be easily performed.

[Brief description of the drawings]

FIG. 1 is a partially omitted front view showing a preferred embodiment of a torsional damper according to the present invention.

FIG. 2 is a cross-sectional view taken along a line X-O in FIG.

FIG. 3 is a sectional view taken along a line YO in FIG. 1;

FIG. 4 is an explanatory diagram showing an operation according to the embodiment.

FIG. 5 is a partially omitted front view showing a torsional damper according to the related art.

FIG. 6 is a sectional view taken along the line XO in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Hub 11 Outer diameter cylinder part 11a Outer peripheral surface 12 Raised surface 13 Shaft hole 20 Mass body 20a Inner peripheral surface 21 Concave surface 30 Elastomer 31 Convolution part

Claims (2)

[Claims] 1. A hub (10), an annular mass body (20) concentrically arranged on the outer periphery of the hub (10), and an outer peripheral surface (11a) of the hub (10) and opposed thereto. An annular elastomer (30) press-fit between the inner surface (20a) of the mass body (20) and an outer peripheral surface (11a) of the hub (10); A partial raised surface (12) is formed at one of an inner peripheral surface (20a) of the mass body (20) at a plurality of circumferential positions, and an outer peripheral surface (11a) of the hub (10) and the mass body. A torsional damper characterized in that a partial concave surface (21) corresponding to each of the raised surfaces (12) is formed on the other of the inner peripheral surfaces (20a) of (20). 2. The method according to claim 1, wherein the outer peripheral surface (11a) of the hub (10) and the inner peripheral surface (20a) of the mass body (20) are located between the respective raised surfaces (12) and the respective concave surfaces (21). A torsional damper characterized in that a section between the sections (1) and (2) is formed in a cylindrical shape.