JPH03168441A - Fluid-sealed type power unit mount - Google Patents

Abstract

PURPOSE:To effectively reduce a vibration phenomenon so as to improve durability of a rubber elastic unit by preparing three fluid chambers to form a double- orifice structure while providing a means for press fit-fixing the rubber elastic unit in a condition that a preload is given in the axial direction. CONSTITUTION:A fluid-sealed power unit mount is charged with a rubber elastic unit 3 between almost coaxially arranged inner and outer cylinders 1, 2. The first subfluid chamber, which communicates with a main fluid chamber 4 through a long orifice 50 formed along one end edge part of the outer cylinder 2, is formed. The second subfluid chamber, which communicates with the main fluid chamber 4 through a short orifice 60 in the outer end edge part of the outer cylinder 2, is formed. Three chambers are prepared for the fluid chambers to form a double-orifice structure while providing a means for press fit-fixing the rubber elastic unit in the axial direction in a condition that a preload is given. Thus, being possible to effectively reduce a vibration phenomenon, durability of the rubber elastic unit can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fluid-filled power unit mount used to support a power unit mounted on a vehicle on a vehicle body.

(Prior Art) Generally, a power unit composed of an engine, a transmission, etc. is supported on a vehicle body via a power unit mount to reduce transmission of vibrations from the power unit to the vehicle body.

As an example of such a power unit mount, the one described in Japanese Patent Application Laid-open No. 61-65935 is known, and this conventional source describes an inner cylinder, an outer cylinder, and a rubber elastic body loaded between the inner cylinder and the outer cylinder. a main fluid chamber whose volume changes with relative displacement of the inner cylinder and the outer cylinder; an orifice formed in a block fitted to the outer periphery of the inner cylinder; and a secondary fluid chamber communicating with the main fluid chamber through the orifice. A power unit mount with a fluid chamber is shown.

(Problems to be Solved by the Invention) However, the conventional fluid-filled power unit mount described above has the following problems.

■ Fluid movement between the main fluid chamber and the auxiliary fluid chamber only takes place through one orifice, so there is only one fluid movement path.
There is only one path, and it can only respond to one vibration phenomenon, for example, one of idle vibration and engine shake.

■ In the orifice formed on the inner cylinder side, the orifice length is short, so the resonance point of the fluid dynamic damper, which uses the fluid in the orifice as mass and the expansion elasticity of the fluid chamber as a spring, appears in the high frequency range. Eike (
It is not possible to dampen input vibrations in a low frequency range such as (around +01-1z) using the dynamic damper effect.

■ The part of the rubber elastic body that forms the chamber wall of the fluid chamber is formed thin to ensure a sufficient amount of chamber volume change, and because it repeatedly expands and contracts when vibration is input, the durable life of the rubber elastic body appears early. .

The present invention has been made by focusing on the conventional problem as described above, and in a fluid-filled power unit mount that communicates with a plurality of fluid chambers or orifices, there are two types of vibration phenomena including input vibration in the low frequency range. The objective is to have the ability to effectively reduce the amount of carbon dioxide and to improve the durability of the rubber elastic body.

(Means for Solving the Problems) In order to solve the above problems, in the fluid-filled power unit mount of the present invention, three fluid chambers are provided, a double orifice structure is provided, and the rubber elastic body is oriented in the axial direction. This is a means of press-fitting and fixing with preload applied.

That is, a cylinder and an outer cylinder are connected to one or the other of the power unit and the vehicle body, respectively, and are bonded to the inner cylinder and press-fitted into the outer cylinder, which is a separate body, with preload applied in the radial direction of the shaft. A main fluid chamber whose volume changes with relative displacement of the inner cylinder and the outer cylinder, and a long orifice formed along one end edge of the outer cylinder, and the main flow fluid flows through the main flow chamber through a long orifice formed along one end edge of the outer cylinder. A first sub-fluid chamber communicating with the main fluid chamber, and a second sub-fluid chamber communicating with the main fluid chamber via a short orifice formed along the other end edge of the outer cylinder. It is characterized by

(Function) When vibration is input from the power unit, the inner tube and the outer tube are displaced relative to each other due to the vibration input, the rubber elastic body is deformed, and the volume of the main fluid chamber is changed.

When the volume of the main fluid chamber changes, two paths are formed: a fluid movement path that communicates with the first sub-fluid chamber via the long orifice, and a fluid movement path that communicates with the second sub-fluid chamber via the short orifice. be done.

Therefore, for example, if the target vibrations to be vibration-proofed are idle vibration and engine shake, for an engine shake that is around 10H2 and has a relatively large amplitude (approximately ±Inn),
If the resonance point of the fluid dynamic damper, in which the fluid in the long orifice is the mass and the expansion elasticity of the main fluid chamber and the first sub-fluid chamber is the spring, is set around 1011■, then 10H7
A resonance phenomenon occurs in which the fluid in the long orifice violently reciprocates due to the input vibrations back and forth, and the input vibrations can be damped. That is, the input vibration energy is absorbed by the flow resistance when the fluid reciprocates violently within the long orifice.

Note that since the walls of the main fluid chamber have high pressure resistance, the volume of the main fluid chamber hardly changes, and almost no fluid flows within the short orifice.

Also, the amplitude is relatively small (±0.3
mm) For idle vibrations, the long orifice, where the fluid passage resistance becomes large, becomes closed, so fluid movement is performed between the main fluid chamber and the second sub-fluid chamber via the short orifice. The movement of the fluid through this short orifice promotes deformation of the rubber elastic body, and vibrations can be damped by lowering the dynamic spring constant.

In addition, since the rubber elastic body is press-fitted and fixed into a separate outer cylinder with preload applied in the axial radial direction, the internal stress due to the preload will decrease as the rubber elastic body expands, and the chamber volume will decrease. The load on the rubber elastic body, which deforms significantly due to changes in , is reduced and its durability is improved.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1 to 3 show a fluid-filled power unit mount according to an embodiment of the present invention.

This fluid-filled power unit mount includes an inner cylinder 1 and an outer cylinder 2 that are arranged approximately coaxially.
A rubber elastic body 3 is loaded between them.

The inner cylinder 1 is fixed to the power unit (or vehicle body) by a bolt inserted inside, and the outer cylinder 2 is fixed to the vehicle body (or the vehicle body).
or a power unit), and the static load of the power unit is supported by the vehicle body via the rubber elastic body 3.

A main fluid chamber 4 is formed in the lower part of the rubber elastic body 3, and a diaphragm 40 is formed above the main fluid chamber 4.
A space 41 is formed through the space.

Further, the upper part of the rubber elastic body 3 is divided into left and right parts by a slit 30 formed at the center in the axial radial direction, and one of the upper parts is divided into left and right parts.
A sub-fluid chamber 5 is formed, and a second sub-fluid chamber 6 communicating with the main fluid chamber 4 via a short orifice 60 is formed on the other side.

Note that space portions 52 and 62 are formed inside the first and second sub-fluid chambers 5 and 6 via a diaphragm 5L6+, and the main fluid chamber 4 and the first and second sub-fluid chambers 5 and 6 and long,
A fluid L is sealed within the short orifice 50,60.

The inner periphery of the rubber elastic body 3 is vulcanized and bonded to the outer periphery of the inner cylinder 1, and the outer periphery is press-fitted and fixed to the inner periphery of the outer cylinder 2 via left and right reinforcing rings 70, 71.

During this press-fitting, the rubber elastic body 3 is compressed in the radial direction of the shaft, and in this case, as shown in FIG. It is press-fitted in the direction.

Furthermore, when the rubber elastic body 3 is press-fitted, the long orifice 50 and the short orifice 60 are simultaneously formed. That is, an L-shaped groove 72 is formed on the edge of the reinforcing ring 70.71.
．． 73, and an inward flange portion 20 at the end edge of the outer cylinder 2 on the back side with respect to the press-fitting direction (arrow direction).
is formed, and after inserting the rubber elastic body 3 into the inside of the Gaisho 2 as shown in FIG. A space surrounded by 72 is formed as a long orifice 50.

Next, after applying preload in the axial direction to the rubber elastic body 3 and compressing it to the position shown in FIG. L-shaped groove 7
3, a space surrounded by the flange portion 21 and the L-shaped groove portion A3 is formed as a short orifice 60.

Note that an opening 50a facing the main fluid chamber 4 and an opening 50b facing the first sub-fluid chamber 5 are cut out in the L-shaped groove 72 forming the long orifice 50, and a short orifice 60 is formed. An opening 60 a facing the main fluid chamber 4 and an opening 60 b facing the second sub-fluid chamber 6 are cut out in the L-shaped groove 73 .

Next, the effect will be explained.

When inputting vibration from the power unit, inner cylinder 1 and outer cylinder 2
The rubber elastic body 3 deforms and the volume of the main fluid chamber 4 changes, and this change in the volume of the main fluid chamber 4 causes fluid movement between the auxiliary fluid chambers 5 and 6. It is done.

In this case, in this embodiment, there is a movement path in which fluid is moved between the main fluid chamber 4 and the first sub-fluid chamber 5 via the long orifice 60, and a movement path in which the fluid is moved between the main fluid chamber 4 and the first sub-fluid chamber 5 via the short orifice 60. Two movement paths are formed, including a movement path in which fluid is moved between the second sub-fluid chamber 6 and the second sub-fluid chamber 6 .

In this embodiment, the fluid movement by the long orifice 50 is used as a countermeasure against engine shake (Figs. 4 and 5), and the fluid movement by the short orifice 60 is used as a countermeasure against idle vibration (Fig. 6). (Fig. and Fig. 7).

*For an engine shake with a relatively large amplitude (approximately ±1 mm) around 10H2 during engine shake, the expansion elasticity of the main fluid chamber 4 and the first sub-fluid chamber 5 is determined by using the fluid L in the long orifice 50 as a mass. The resonance point of the fluid dynamic damper with spring is 1
When the value is set to around 002, a resonance phenomenon occurs in which the fluid L in the long orifice 50 reciprocates in a wide range due to an input vibration of around 10 Hz, and engine shake can be damped.

That is, the input vibration energy is absorbed by the flow resistance when the fluid L reciprocates violently within the long orifice 50.

Since the diaphragm 40 of the main fluid chamber 4 has a high pressure resistance, the volume of the main fluid chamber 4 hardly changes, and almost no fluid flows through the short orifice 60.

*During idle vibration, the amplitude is relatively small at 20-30H2 (±0.3mm)
degree) For idle vibrations, the long orifice 50, where fluid passage resistance increases, is closed, so fluid movement is performed between the main fluid chamber 4 and the second sub-fluid chamber 6 via the short orifice 60. As the fluid L moves through the short orifice 60, deformation of the rubber elastic body 3 is promoted, and vibrations can be damped by lowering the dynamic spring constant.

That is, if the resonance point of the fluid dynamic damper, which uses the fluid L in the short orifice 60 as a mass and the expansion elasticity of the main fluid chamber 4 and the second sub-fluid chamber 6 as a spring, is set in a frequency range of 30H2 or higher, this In the frequency range below the resonance point, the fluid L exhibits an effect of flowing within the short orifice 60 according to the volume change of the main fluid chamber 4 and the second sub-fluid chamber 6, promoting deformation of the rubber elastic body 3, This will reduce the dynamic spring constant.

In addition, since the rubber elastic body 3 is press-fitted and fixed into the external cylinder 2, which is a separate body, with preload applied in the axial radial direction, the internal stress due to the preload will decrease as the rubber elastic body 3 expands. ,
The load on the rubber elastic body 3, which deforms significantly as the chamber volume changes, is reduced and its durability is improved.

As described above, this embodiment has the features listed below.

■ Since fluid movement between the main fluid chamber 4 and the first and second sub-fluid chambers 5 and 6 is performed through the long orifice 50 and the short orifice 60, there are two paths for fluid movement, which reduces engine shake and idle vibration. It can cope with two vibration phenomena.

■ Since the long orifice 50 is formed along the edge of the outer cylinder, the orifice length can be set sufficiently long, and the fluid dynamic damper uses the fluid inside the orifice as a mass and the expansion elasticity of the fluid chamber as a spring. The resonance point of the engine can be set in a low frequency range of around 10 Hz, which is the engine shake region, and engine shake can be suppressed by the dynamic damper effect.

■ Since the rubber elastic body 3 is press-fitted and fixed into the separate outer cylinder 2 with preload applied in the axial radial direction, the internal stress due to the preload will decrease as the rubber elastic body 3 expands.
The load on the rubber elastic body 3, which deforms significantly as the chamber volume changes, is reduced and its durability is improved.

■ Long. In forming the short orifice 50, 60, the reinforcing rings γ0, 71 provided on the rubber elastic body 3 and the outer cylinder 2 fixed by caulking are used, which eliminates the need for a separate member for forming the orifice, reducing costs. It is advantageous.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and even if there are design changes within the scope of the gist of the present invention, they are included in the present invention. It will be done.

For example, the long and short orifices may be formed from separate members from the reinforcing ring.

Further, it can also be applied as a countermeasure against vibrations other than idle vibration and engine shake.

(Effects of the Invention) As explained above, in the present invention, in a fluid-filled power unit mount in which a plurality of fluid chambers are communicated through an orifice, three fluid chambers are provided and a double orifice structure is provided. Since the rubber elastic body is press-fitted and fixed with preload applied in the axial direction, it has the ability to effectively reduce two types of vibration phenomena including input vibration in the low frequency range, and the rubber elastic body The effect of improving durability can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a fluid-filled power unit mount according to an embodiment of the present invention with the outer cylinder removed, Fig. 2 is a sectional view of the fluid-filled power unit mount, and Fig. 3 is a rubber of the fluid-filled power unit mount. An explanatory diagram of the state in which the elastic body is press-fitted into the outer cylinder, Fig. 4 is a sectional view taken along line II in Fig. 2, Fig. 5 is a plan development view of the long orifice, Fig. 6 is a sectional view in Fig. 2, FIG. 7 is a plan development view of the short orifice. 2.--Outer cylinder 3...Rubber elastic body 4...Main fluid chamber 40...Diaphragm 41...Space 30...Slit 50...Long orifice 5...First auxiliary fluid Chamber 60...Short orifice 6...Second auxiliary fluid chamber 54.61...Diaphragm 52, 62...Space 70.71...Reinforcement ring 72.73...Chorus groove 20. ...Flange portion 21...Flange 50a. 50b---opening 60a. 60b...opening

Claims (1)

[Claims] 1) An inner cylinder and an outer cylinder connected to one or the other of the power unit and the vehicle body, respectively, and a preload applied to the outer cylinder, which is a separate body and is adhered to the inner cylinder, in the axial radial direction. a rubber elastic body press-fitted and fixed in a given state; a main fluid chamber whose volume changes with relative displacement of the inner tube and the outer tube; and a long orifice formed along one edge of the outer tube. a first sub-fluid chamber that communicates with the main fluid chamber via a second sub-fluid chamber that communicates with the main fluid chamber via a short orifice formed along the other end edge of the outer cylinder; A fluid-filled power unit mount characterized by the following.