JP2888874B2 - Fluid filled type vibration damping device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-vibration device used for an automobile engine mount or the like for supporting an engine in an anti-vibration manner, and more particularly, to an anti-vibration anti-vibration device in which a fluid is enclosed. It concerns the device.

[Prior art and problems to be solved]

Generally, in a vibration isolator supporting a vibrating body such as an engine of an automobile, various vibrations having different numbers of revolutions and different amplitudes are generated depending on the rotation state. It is required to use a vibration device capable of absorbing the vibration of the above.

As a vibration isolator that absorbs such a wide range of vibrations, the main body is formed of an elastic body, and the opening of the void formed inside the elastic body is closed with a diaphragm, and
A partition is provided in the space to partition the interior into two chambers to form a main fluid chamber and a sub-fluid chamber, and the partition is provided with two orifices communicating with the two chambers. A configuration filled with an incompressible fluid is already known.

In the structure configured as described above, the elastic body side is fixed to a vibration body such as an engine, and the diaphragm side is fixed to a vibration transmission side such as a chassis, and vibration from the vibration body side is directly transmitted to the vibration transmission side. It is prevented from being transmitted to.

In this case, when the vibrating body is an automobile engine, various vibrations having different numbers of amplitudes and amplitudes are generated. In the case of a low frequency and large amplitude, a small diameter first orifice which is always in communication is used. In the case of low frequency and small amplitude (during idling), a large diameter orifice is used.

The transmission of the vibration from the vibrating body to the vibration transmitting side is attenuated by the resistance when the fluid flows through the orifice during the above operation.

In the above case, the relationship between the frequency of the vibrating body and the dynamic spring constant of the vibration isolator is indicated by a curve I in FIG. In some cases, the dynamic spring constant becomes extremely small, and thereafter, it suddenly increases to cause a peak portion of the dynamic spring constant.

As for the dynamic spring constant in the case of a vibration isolator using a large-diameter orifice, the smaller the value due to resonance when a fluid flows through the orifice, the larger the subsequent peak portion becomes. Have.

On the other hand, the dynamic spring constant when only the small-diameter orifice is used and the large-diameter orifice is not used is as follows.
As shown by curve II in Fig. 10, the value is almost constant, and when the frequency is small, the dynamic spring constant becomes larger than when a large-diameter orifice is used. The dynamic spring constant is smaller than when using.

For this reason, it is conceivable to switch the large-diameter orifice at the frequency where the dynamic spring constant between the case where the large-diameter orifice is used and the case where the large-diameter orifice is not used is a boundary. When switching a large-diameter orifice, the problem of responsiveness inevitably arises. For this reason, after the dynamic spring constant becomes a high value,
Since the dynamic spring constant of the small-diameter orifice is used, there is a problem that the dynamic spring constant is close to the peak value when a large-diameter orifice is used.

The present invention solves the above-mentioned problems of the prior art, and the dynamic spring constant when a large-diameter orifice is used is lower than the dynamic spring constant when a small-diameter orifice is used. Use a large-diameter orifice in the power range, use a small-diameter orifice in other areas, and use an orifice with a dynamic spring constant due to responsiveness when switching large-diameter orifices. It is an object of the present invention to provide a fluid-filled type vibration damping device that can prevent a value close to a peak value in the case of performing the above.

[Means for solving section death]

In order to solve the above-described problems, the present invention provides a first orifice that supports a vibrating body and constantly opens an internal opening of an elastic body that is deformed with the vibration of the vibrating body, and a second orifice that can be opened and closed. Closed by a partition having, a diaphragm is provided on the side of the partition opposite to the elastic body, a main fluid chamber is formed between the elastic body and the partition, and a sub fluid chamber is formed between the partition and the diaphragm. A fluid-filled vibration isolator in which both fluid chambers can be communicated with each other through a first orifice and a second orifice of the partition, and further, a fluid is filled in the fluid chambers. Providing a valve member for opening and closing the second orifice in accordance with the vibration frequency of the vibrating body, wherein the natural frequency of the diaphragm substantially matches the natural frequency of the entire apparatus when the second orifice is open. In so that the mass of the diaphragm, stiffness, and has a structure in which to set the weight of the secondary fluid chamber of the fluid.

Further, the valve member is configured to be operated by an actuator that operates at a predetermined vibration frequency of the vibrating body.

Further, the valve member has a cylindrical shape with one end closed, and an opening is formed in a side surface, and is rotatable inside a simple member provided inside the partition and forming a part of the second orifice. And the opening portion can be changed from a state in which the second orifice is completely opened to a state in which the second orifice is completely closed according to the rotating state.

[Action]

According to the present invention, by employing the above-described means, the dynamic spring constant that varies with the frequency when the second orifice is used and the dynamic spring constant that varies with the frequency when the first orifice is used are determined. Switching can be performed when both dynamic spring constants match so that a small portion is used. Further, the increase in the dynamic spring constant caused by the response delay occurring at the time of the switching should be reduced by causing the diaphragm to resonate. Can be done.

〔Example〕

Hereinafter, embodiments of the present invention shown in the drawings will be described.

1 and 2 are cross-sectional views of a fluid-filled type vibration damping device according to the present invention, taken along different cut surfaces.

As shown in FIGS. 1 and 2, the fluid filled type vibration damping device 1 has a conical cylindrical elastic body 2 made of thick rubber and a housing 3 made of a rigid material such as a steel plate. .

The housing 3 includes a substantially cylindrical main line 3a and a base 3b fixedly coupled to a lower portion of the main portion 3a by caulking a lower end of the main portion 3a. The housing 3 is integrally formed with a lower end of the base 3b. The fixed flange 3c is fixed to the vehicle body frame.

A mounting bracket 5 having a boss collar 4 is embedded in the upper part of the elastic body 2, and a mount bracket 6 for supporting an engine is mounted on the boss collar 4.

A fixed plate 7 is vulcanized and bonded to the lower end of the elastic body 2, and the fixed plate 7 is joined to the upper end of the housing 3.

As described above, the engine, which is a vibrating body, is supported by the elastic body 2, and the elastic body 2 is elastically deformed in accordance with the vibration.

A stopper bracket 8 is attached to the upper end of the housing 3 so as to straddle the elastic body 2.
Abutting the top of the elastic body 2 to prevent excessive deformation of the elastic body 2 upward, and the lower end surface of the mount bracket 6 comes into contact with the rubber stopper 9 integrally formed on the upper surface of the lower end of the elastic body 2. The contact is formed so that excessive deformation of the elastic body 2 downward is prevented.

A partition 10 is provided below the elastic body 2 inside the fluid-filled type vibration damping device 1.
The main body 3a can be fixed to the housing 3 by being sandwiched between the lower end of the main body 3a and the base 3b.

A flexible diaphragm 11 made of thin rubber is attached to the lower side of the partition 10, and the outer peripheral edge of the diaphragm 11 is in contact with the lower surface of the partition 10 and the housing 3.
The lower surface side of the partition wall 10 is sealed between the upper end surface of the base portion 3b and the upper end surface of the base portion 3b.

As described above, a chamber is formed inside the fluid-filled type vibration damping device 1 by the elastic body 2, the housing 3, and the diaphragm 11, and the inside is formed with the first orifice, which is a flow path described later, and the first orifice. The chamber 10 is divided into two chambers by a partition wall 10 having two orifices 20 formed therein. An incompressible fluid such as water or oil is sealed in both chambers.
One of the two chambers is formed in the main fluid chamber 12, and the other chamber is formed in the sub-fluid chamber 13.

Since the main fluid chamber 12 formed above the partition 10 has a part of the chamber wall formed by the elastic body 2, the elastic body 2 is deformed by the vibration of the engine, thereby changing the internal volume. The sub-fluid chamber 13 formed below the partition 10 has a part of the chamber wall formed by the diaphragm 11, and the lower surface side of the diaphragm 11 is subjected to atmospheric pressure. The auxiliary fluid chamber 13
The diaphragm 11 is deformed according to the internal fluid pressure, and the internal volume is freely changed. The volume change of the main fluid chamber 12 and the sub fluid chamber 13 is caused by the first orifice and the second orifice. This is done by moving the fluid through 20.

The diaphragm 11 is formed of an elastic material having a predetermined mass and rigidity. In this case, the mass and rigidity of the diaphragm 11 and the auxiliary fluid chamber are set so that the natural frequency of the diaphragm 11 substantially matches the natural frequency of the entire device determined by the elastic body 2 and the second orifice 20.
The weight of the fluid in 13 is set. Here, the natural frequency f of the diaphragm 11 is as follows, where m is the mass of the diaphragm 11, and k is the spring constant. (N = 1, 2, 3,...), And a resonance phenomenon called surging occurs at this frequency. This resonance phenomenon is determined by the mass and rigidity of the diaphragm 11,
The weight of the fluid in the sub-fluid chamber 13 affects the rigidity of the diaphragm 11 because the diaphragm 11 is very soft.

On the other hand, the partition 10 for forming the main fluid chamber 12 and the sub-fluid chamber 13 as described above is formed of a partition member 14 and a cover member 15 as shown in FIGS.

That is, the partitioning member 14 has a case 16 having a cylindrical shape with an upper end closed and a flange 16a formed at the lower end, and a part of the upper surface of the case 16 is concavely inward in a half-moon shape. A half-moon recess 16b is formed, and a hole 16c is formed on the upper surface.
Is formed, and this functions as a first orifice.

Inside the case 16, the portion corresponding to the linear portion of the meniscus recess 16b has a simple member 17 in which a rectangular opening is formed, serving in a state where it penetrates in the horizontal direction, In this state, the inside of the case 16 is filled with rubber 18 and vulcanized (see FIG. 6).

A groove 19 is formed on the lower surface of the filled rubber 18 so as to surround the quarter moon portion 16b, and a portion of the groove 19 corresponding to the hole 16c formed in the upper surface of the case 16 is formed. Along with forming the through hole 18a, an opening 18b corresponding to the opening of the cylindrical member 17 is also formed.Therefore, the hole 16c inside the cylindrical member 17 and the upper surface of the case 16 is
It is designed to communicate within 9.

On the other hand, the lid member 15 has a plate-like shape that closes the lower surface of the partition member 14, and has a through-hole formed in the groove 19.
A hole 15a is drilled at a position corresponding to the portion separated from the opening 18a and the opening 18b.Therefore, when the partition member 14 and the cover member 15 are combined, the cover member 15 is formed from the hole 16a through the groove 19. A first orifice reaching the hole 15a of the fifteenth and a second orifice reaching the hole 15a of the lid member 15 from the cylindrical member 17 via the groove 19;
An orifice is formed.

In addition, the rotary valve member 21 disposed inside the partition wall 10 configured as described above has a cylindrical shape with one end closed as shown in FIG. Is provided with an arc-shaped projection 22a, and has an opening 22b on the peripheral surface corresponding to the opening of the cylindrical member 17 embedded in the partition 10.
And a rod 23 protruding from the center of the closed end of the main body 22.

In addition, a hole 24a substantially matching the inner diameter of the main body 22 of the rotary valve member 21 is formed in the linear portion of the meniscus concave portion 16b formed in the case 16 of the partition member 14, and this hole is formed. A regulating member 24 is provided in which a part of 24a is larger than the outer diameter of the main body 22 of the rotary valve member 21 and is formed in an arc shape longer in the circumferential direction than the arc-shaped protrusion 22a of the main body 22. ing.

Therefore, when the rotary valve member 21 is inserted into the cylindrical member 17 of the partition member 14, the opening end of the main body 22 is
Further insertion is prevented in a state where only the arc-shaped projection 22a protrudes from the hole 24a of the regulating member 24.
The rotary valve member 21 is rotatable within a range in which the arc-shaped projection 22a contacts both ends of the large-diameter arc-shaped portion of the regulating member 24.

The rod 23 of the rotary valve member 21 projects outward and is driven to rotate by an actuator 25 that operates according to the number of rotations of the engine.

 Next, the operation of the above will be described.

First, at the time of idling of the engine, the rotation speed of the engine is detected and the actuator 25 is operated to rotate the rotary valve member 21 via the rod 23, and the main body of the rotary valve member 21 is rotated.
The 22 arc-shaped protrusion 22a is brought into contact with one end of the arc-shaped portion of the regulating member 24.

In this state, since the opening 22b of the main body 22 of the rotary valve member 21 and the opening of the cylindrical member 17 provided in the partition member 14 are aligned, the main fluid chamber 12 and the auxiliary fluid A second orifice in which the chamber 13 is formed by the semicircular recess 16b, the inside of the main body 22 of the rotary valve member 21, the groove 19 of the partition member 14, and the lid member 15.
It is in a state of communication through 20.

The first orifice from the hole 16a of the case 16 to the hole 15a of the lid member 15 via the groove 19 is always open.

In this state, if low-frequency vibration at the time of idling of the engine acts on the engine mount, this vibration is generated by the elastic body 2.
The elastic body 2 is pushed downward, and the main fluid chamber 12 contracts.

Therefore, the fluid inside the main fluid chamber 12 is pushed downward and flows into the sub-fluid chamber 13 through the second orifice 20 formed inside the partition 10.

Therefore, the volume of the interior of the sub-fluid chamber 13 is increased by being combined with the fluid filled in the interior of the sub-fluid chamber 13, thereby pushing down the diaphragm 11 and thus increasing the volume. The fluid in the sub-fluid chamber 13 flows into the main fluid chamber 12 again through the orifice 20, and this operation is repeated.
The fluid located in the orifice 20 resonates and increases the flow resistance, thereby ensuring attenuation at low frequency and small amplitude.

On the other hand, when low-frequency, large-amplitude vibration is applied, the first orifice exerts a damping effect.

When the frequency of vibration acting on the engine mount is increased by sequentially increasing the rotation speed of the engine, the dynamic spring constant gradually increases, and the dynamic spring constant when the second orifice is not used at a certain rotation speed is increased. A state that is consistent with the constant, that is, the dynamic spring constant when only the first orifice is used.

When this rotation speed is reached, the actuator 25
To rotate the rotary valve member 21 to rotate the second orifice.
If the 20 is closed, the dynamic spring constant of the device from this point on will be that of the case where the second orifice 20 is not used, and only the first orifice will be used for the input vibration at a higher rotational speed. Although it should be possible to exert the extinction effect, the response delay is inevitably caused, and the dynamic spring constant when the second orifice 20 is used until the predetermined rotation speed is reached.

For this reason, the dynamic spring constant may increase to near the peak of the dynamic spring constant when the second orifice is used, so that a satisfactory damping effect cannot be obtained.

However, in the present invention, the mass and rigidity of the diaphragm 11 and the weight of the fluid inside the sub-fluid chamber 12 substantially coincide with the peak frequency of the dynamic spring constant when the second orifice 20 is used. Therefore, when approaching the peak frequency of the dynamic spring constant due to the response delay, the diaphragm 11 resonates and lowers the dynamic spring constant,
Thereafter, the dynamic spring constant when the second orifice 20 is not used is obtained.

Therefore, for a vibration input at a higher engine speed, the dynamic spring constant does not use the second orifice, so that a damping effect can be exhibited.

That is, as shown in FIG. 10, the dynamic spring constant when the second orifice is used in addition to the first orifice which is always open is low at the low frequency as shown by the curve I,
It increases as the frequency increases, peaks at a certain frequency, and reaches the first without using the second orifice.
When only the orifice is used, the level is almost the same as shown by the curve II.

When the second orifice is closed by operating the actuator at the rotation speed corresponding to the frequency at which the two curves I and II match, the dynamic spring constant further increases in the state of the curve I due to the response delay. The state shown by the curve II is obtained, and the characteristic shown by the arrow in FIG. 7 becomes a value close to the peak value when the second orifice is used.

On the other hand, when the diaphragm 11 resonates when the second orifice is used, the peak value is significantly reduced as compared with the case where the diaphragm 11 does not resonate as shown in FIG.

Therefore, according to the present invention, when the frequency is lower than the predetermined frequency, the second orifice is used in addition to the first orifice, and when the predetermined frequency is reached, the second orifice is used.
The orifice was deactivated, and at higher frequencies the second orifice was not used, and the diaphragm resonated, so that the dynamic spring constant was as shown by the arrow in FIG. Characteristics can be obtained.

The frequency at which the actuator is operated is not limited to the frequency at which the dynamic spring constant of the case where the second orifice is used and the case where the second orifice is not used, but can be switched at any frequency. Furthermore, the variable orifice can be obtained by operating the actuator stepwise, so that the entire apparatus can have the best dynamic spring constant.

Further, the fluid filled type vibration damping device according to the present invention can be used not only as a mount for an engine but also as a mount for various vibration sources.

〔The invention's effect〕

The present invention is configured as described above, and the mass, stiffness, and fluid in the sub-fluid chamber of the diaphragm are adjusted so that the natural frequency of the diaphragm substantially matches the natural frequency of the entire device when the second orifice is open. Of the dynamic spring constant when the second orifice is used in addition to the first orifice, and the dynamic spring constant when the second orifice is not used. Of the dynamic spring constant can be adopted, and the rise of the dynamic spring constant caused by the delay in response when switching between the characteristics of the two dynamic spring constants can be reduced by resonating the diaphragm. Therefore, the dynamic spring constant can be kept low over a wide range from low frequency to high frequency, and the damping effect on the input vibration In which excellent effects such as will be able to significantly improve.

[Brief description of the drawings]

The drawing shows a fluid filled type vibration damping device according to the present invention,
FIG. 2 is a longitudinal sectional view, FIG. 2 is a longitudinal sectional view in a direction orthogonal to that shown in FIG. 1, FIG. 3 is a schematic perspective view showing a partition member and a lid member, and FIG. 5 is a schematic view showing a rotary valve member, FIG. 6 is a longitudinal sectional view of a partition, FIG. 7 is a view showing a response delay, FIG. 8 is a case where a diaphragm resonates, and FIG. FIG. 9 is a diagram showing characteristics of a dynamic spring constant according to the present invention, and FIG.
FIG. 10 is a diagram showing characteristics of a dynamic spring constant when an orifice is used and when an orifice is not used. DESCRIPTION OF SYMBOLS 1 ... Fluid filled type vibration isolator 2 ... Elastic body 3 ... Housing 4 ... Boss collar 5 ... Mounting bracket 6 ... Mounting bracket 7 ... Fixing plate 8 ... Stopper bracket 9 ... Rubber stopper part 10 ... Partition wall 11 ... Diaphragm 12 ... Main fluid chamber 13 ... Sub-fluid chamber 14 ... Partition member 15 ... Lid 16 ... Case 16a ... Flange 16b ... Half-moon recess 16c ... Hole 17 ... Cylindrical member 18 Rubber 18a Through hole 18b Opening 19 Groove 20 Orifice 21 Rotating valve member 22 Body 22a Arc-shaped protrusion 22b Opening 23 Rod 24 …… Regulation member 25 …… Actuator

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-102943 (JP, A) JP-A 62-184239 (JP, U) JP-A 59-123731 (JP, U) JP-A 58- 147818 (JP, U) Fully open 61-79037 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16F 13/00

Claims (3)

(57) [Claims] An internal opening of an elastic body that supports a vibrating body and deforms with the vibration of the vibrating body is closed by a partition having a first orifice that is always open and a second orifice that can be opened and closed. A diaphragm is provided on the side of the partition opposite to the elastic body, a main fluid chamber is formed between the elastic body and the partition, and a sub-fluid chamber is formed between the partition and the diaphragm. First orifice and second partition wall
A fluid-filled type vibration damping device that is capable of communicating via an orifice and further has a fluid filled in the two fluid chambers, wherein the second orifice is opened and closed in the partition according to a vibration frequency of a vibrating body. And the mass and rigidity of the diaphragm and the fluid in the sub-fluid chamber so that the natural frequency of the diaphragm substantially matches the natural frequency of the entire device when the second orifice is open. A fluid filled type vibration damping device characterized by setting the weight of a fluid. 2. The fluid filled type vibration damping device according to claim 1, wherein said valve member is operated by an actuator which operates at a predetermined vibration frequency of said vibrating body. 3. The valve member has a cylindrical shape with one end closed, and has an opening formed in a side surface, and is provided inside a cylindrical member provided inside the partition and forming a part of a second orifice. 3. The fluid-filling type prevention device according to claim 1, wherein the device is rotatably provided, and the opening portion can be changed from a state in which the second orifice is completely opened to a state in which the second orifice is completely closed according to the state of rotation.