JPH11230243A - Vibration control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control vibrations of a wide range of frequency. SOLUTION: A switching valve 82 is formed with a recession 82A in its opposed to a second diaphragm 68, the space between the recession 82A and second diaphragm is used as a second air chamber 74. The switching valve 82 has a fitting hole 82B made therein, in which a valve element 84 is set for turning motion by a motor 86 that is connected thereto as a constituent of the switching valve 82. The switching valve 82 is further formed with an atmospheric passage 96 that extends from the fitting hole 82B up along the switching valve 82 to connect the fitting hole 82B up to the atmospheric air outside the switching valve 82. The fitting hole 82B is further made to communicate with an intake manifold 92 by way of a negative pressure passage 98 that extends from the fitting hole 82B down along the switching valve 82 as well as of a connecting pipe 90.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration isolator that absorbs and attenuates vibration from a vibration generator, and is used for vehicles and general industrial machines, and is suitable for an engine mount.

[0002]

2. Description of the Related Art An anti-vibration device as an engine mount is provided between an engine of an automobile and a vehicle body so as to prevent the vibration of the engine from being transmitted to the vehicle body. Further, there are various types of vibrations generated by the engine in accordance with the running and stopped state of the vehicle, and a liquid-filled type vibration damping device has been proposed as a vibration damping device that absorbs these vibrations. .

[0003] As this liquid filled type vibration damping device, there is known a structure having two sub liquid chambers in addition to the pressure receiving liquid chamber, each sub liquid chamber being connected to the pressure receiving liquid chamber by an orifice. I have. A structure in which one of the sub liquid chambers and the air chamber adjacent to each other across the diaphragm are switched between an air state communicating with the atmosphere or a closed shutoff state with the atmosphere by a valve such as a solenoid valve. The state of the air chamber in the vibration isolator is switched by switching with a valve, so that the pumping force of the sub-liquid chamber is changed to change the vibration isolating characteristics. That is, for example, by changing from the atmospheric state to the closed state, the rigidity of the diaphragm increases, and the resonance frequency of the orifice moves to the higher frequency side.

[0004]

However, for example, when the orifice is set to resonate in the frequency range of the idle vibration as shown by a characteristic curve A in FIG. As shown in (2), the resonance frequency of the orifice is shifted to a high frequency side about twice as high as the atmospheric state.

Although this is effective for a low-speed muffled sound generated in a low-speed region of the engine, the region where the dynamic spring constant increases due to the anti-resonance of the orifice is in the region of the high-speed muffled sound generated in the high-speed region of the engine. The overlap causes a high-speed muffled sound to be transmitted to the vehicle body.

The present invention has been made in view of the above circumstances, and has as its object to provide a vibration isolator capable of reducing vibrations in a wide range of frequencies.

[0007]

According to a first aspect of the present invention, there is provided a vibration isolator connected to one of a vibration generator and a vibration receiver, and a first mounting member connected to the other of the vibration generator and the vibration receiver. A second mounting member, an elastic body provided between the first mounting member and the second mounting member, which is deformed when vibration is generated, and which is capable of expanding and contracting the elastic body as a part of a partition wall and encloses a liquid. A main liquid chamber, a main liquid chamber, a sub liquid chamber which is communicated with the main liquid chamber via an orifice and is expandable and contractable, a deformable diaphragm constituting a part of a partition of the sub liquid chamber, and a sub liquid chamber and the diaphragm. An air chamber which is disposed opposite to and is filled with gas;
A valve is provided, which can be switched between an atmospheric state in which the air chamber communicates with the atmosphere side, a closed state in which the air chamber is isolated from the outside, and a negative pressure state in which the air chamber communicates with the intake source.

According to a second aspect of the present invention, in the first aspect, the valve is connected to control means capable of detecting a running or stopped state of the vehicle, and the control means switches the valve. It is characterized by the following.

The operation of the vibration isolator according to claim 1 will be described below. The vibration generated by the vibration generator is transmitted to the elastic body via the first mounting member or the second mounting member.
At this time, the vibration is absorbed by the resistance based on the internal friction of the elastic body, and the passage of the liquid when the liquid flows through the orifice connected to the sub-liquid chamber by expanding and contracting the main liquid chamber in which the elastic body is a part of the partition wall. Absorbed by resistance or liquid column resonance.

An air chamber filled with gas is disposed opposite to the sub-liquid chamber with a diaphragm interposed therebetween. The air chamber communicates with the air side, the air chamber shuts off the air chamber from the outside, and the air chamber shuts off. The valve can switch the state of the air chamber between a negative pressure state and a state of communication with the intake source.

For example, when the vibration isolator is used as an engine mount of a vehicle, not only can the valve be switched between the atmospheric state and the shut-off state, but also the valve can be switched with the negative pressure source. As a result, the dynamic spring constant in the high-speed muffled sound region generated in the high-speed region of the engine can be reduced.

That is, by switching to the negative pressure source when necessary according to the state of the engine, the diaphragm can be completely sucked to the wall surface of the air chamber. When the diaphragm is sucked on the wall surface of the air chamber, the diaphragm is fixed and the liquid does not flow into the sub liquid chamber via the orifice, and the resonance of the liquid in the orifice is prevented.

Therefore, for example, when the orifice is substantially closed by a valve in a structure having one orifice, the vibration is absorbed only by the elastic body.
When one orifice is substantially closed by a valve in a structure having two sub liquid chambers and two orifices, the dynamic spring constant can be reduced by the other orifice.

On the other hand, by connecting the air chamber to the atmosphere side via a valve, or blocking the air chamber from the outside by a valve, the state of the air chamber is different from each other, and the rigidity of the diaphragm is substantially increased. Although different, the respective free movements of the diaphragm can cause resonance of the liquid in the orifice to occur corresponding to the two frequencies.

As described above, by switching the air pressure in the air chamber located opposite to the auxiliary liquid chamber with the diaphragm interposed therebetween by the operation of the valve, even when vibrations having different frequencies are input to the vibration isolator, respectively. Can respond.

As a result, the state of the air chamber is switched between an atmospheric state in which the air chamber communicates with the atmosphere side by the valve, a shutoff state in which the air chamber is isolated from the outside, and a negative pressure state in which the air chamber communicates with the intake source. , The characteristics of the vibration isolator can be changed, and the vibration can be absorbed over a wide frequency range.

The operation of the vibration isolator according to claim 2 will be described below. The present invention has the same function as the first embodiment. However, in the present invention, the valve is connected to control means capable of detecting the running and stop states of the vehicle, and the control means switches the valve.

Accordingly, since the valve is operated by the control means capable of detecting the running and stopping states of the vehicle, the characteristics of the vibration isolator can be changed more reliably and more accurately.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a vibration isolator according to the present invention is shown in FIGS. 1 to 4, and this embodiment will be described with reference to these drawings.

As shown in FIG. 1, an anti-vibration device 1 of this embodiment
0 is provided with a bottom plate 12 as a first mounting member. A mounting bolt 14 projects from the lower center of the bottom plate 12, and the vibration isolator 10 is fixed to the vehicle body (not shown) by using the mounting bolt 14 as an example. Bottom plate 12
Is formed as a cylindrical upright wall portion 12A bent at a right angle, and a flange portion 12B bent at a right angle is continuously formed at an upper end portion of the upright wall portion 12A.

A lower end of a cylindrical outer tube fitting 16 is fixed by caulking to the flange portion 12B of the bottom plate 12, and a rubber elastic film is provided between the flange portion 12B and the lower end of the outer tube fitting 16. The peripheral edge of the first diaphragm 18 is sandwiched. The space between the first diaphragm 18 and the bottom plate 12 is a first air chamber 20, and the first air chamber 20 communicates with the outside through an air hole (not shown) formed in the upright wall 12A.

The upper end of the inner peripheral surface of the outer cylindrical member 16 is formed as an enlarged portion 16B having an enlarged inner diameter. The expanded portion 16B has a rubber elastic member for closing the opening of the outer cylindrical member 16. The outer periphery of the body 22 is vulcanized and bonded. In addition, a part of the elastic body 22 is extended to a lower end of the inner periphery of the outer tube fitting 16,
The outer peripheral side of the elastic body 22 is vulcanized and bonded to the outer tube fitting 16.

At the center of the elastic body 22, a support 24 as a second mounting member is vulcanized and bonded. The support 24 is a mounting portion of an engine (not shown), and mounting bolts 26 for fixing the engine are provided upright.

Here, the inner peripheral portion of the outer tube fitting 16, the elastic body 22
The liquid chamber 28 is formed by the lower end of the
The liquid chamber 28 is filled with a liquid such as ethylene glycol. A columnar partition member 30 made of synthetic resin or the like is arranged in the liquid chamber 28, and divides the liquid chamber 28 into a main liquid chamber 32 and a first sub liquid chamber 34.

On the outer periphery of the partition member 30, a narrow groove 44A having a rectangular cross section is formed along the circumferential direction. Narrow groove 4
4A, a narrow groove 4 extending to the upper surface of the partition member 30 is provided at one end.
4B is connected to the first auxiliary liquid chamber 3 at the other end of the narrow groove 44A.
An opening 44 </ b> C penetrating to the fourth part 4 is connected. Narrow groove 44
A and 44B are closed by the extension of the elastic body 22 on the side of the outer metal fitting 16 to form a first restriction passage 52 which is an orifice communicating between the main liquid chamber 32 and the first sub liquid chamber 34. I have.

Further, the partition member 30 is formed with a rectangular hole 42 extending from the outer periphery toward the center of the partition member 30, and as shown in FIG. A second restriction passage 46, which is an orifice, is formed to communicate with the main liquid chamber 32 through the opening 42A.

The partition member 30 is located on the side surface of the outer tube fitting 16.
A through-hole 48 is formed at a position corresponding to the rectangular hole 42. The outer peripheral surface of the outer tube fitting 16 corresponding to the through-hole 48 is provided with a center through a ring member 56 formed in a ring shape. A block 50 penetrating the part is attached.

A concave portion 54 is formed in the block 50 in a concave shape, and a switching valve 82 as a valve is arranged next to the concave portion 54 side of the block 50. A second elastic film made of rubber is provided between the block 50 and the switching valve 82.
The peripheral edge of the diaphragm 68 is clamped. Because of this,
The concave portion 54 is closed by the second diaphragm 68 to form a second sub liquid chamber 70.

The second diaphragm 68 of the switching valve 82
A concave portion 82A is formed on the surface facing the concave portion 82, and a second air chamber 74 is formed between the concave portion 82A and the second diaphragm 68.

As shown in FIGS. 1 to 3, a valve element 84 is rotatably disposed in a fitting hole 82B formed inside the switching valve 82, and is connected to the valve element 84 to perform switching. Valve 8
The valve element 84 is rotated by a motor 86 which forms a part of the valve element 2. Then, a notch is formed in the valve body 84 by cutting out a part of the valve body 84,
The valve body 84 has a semicircular shape.

A communication passage 94 extending from the fitting hole 82B toward the recess 82A is formed in the switching valve 82. Further, an atmosphere-side passage 96 extending from the fitting hole 82B toward the upper portion of the switching valve 82 is formed. Formed on the switching valve 82,
The fitting hole 82B communicates with the outside air side of the switching valve 82.

On the other hand, a connection pipe 90 connected to an intake manifold 92 serving as an intake source on the intake side of the engine is connected to a lower end of the switching valve 82, and is connected to the switching valve 82.
And the intake manifold 92 are communicated with each other. A negative pressure side passage 98 extending from the fitting hole 82B toward the lower part of the switching valve 82 and the connection pipe 90 communicate the fitting hole 82B and the intake manifold 92.

As described above, when the motor 86 rotates the valve body 84 and the posture of the valve body 84 becomes as shown in FIG. 1, the atmosphere side passage 96 is opened and the negative pressure side passage 98 is closed. The second air chamber 74 is set to the atmospheric state.

Further, the motor 86 rotates the valve body 84,
When the posture of the valve body 84 becomes as shown in FIG. 2, the atmosphere side passage 96 and the negative pressure side passage 98 are closed, respectively, and the second air chamber 74 is shut off.

Further, when the motor 86 rotates the valve body 84 and the posture of the valve body 84 becomes as shown in FIG.
4 closes the atmosphere side passage 96 and opens the negative pressure side passage 98 to put the second air chamber 74 in a negative pressure state.

On the other hand, a motor 86 for rotating the valve body 84
It is connected to a control circuit 60 which is control means for turning on / off the applied voltage by judging the driving condition of the vehicle. The control circuit 60 is driven by a vehicle power supply, and can detect a vehicle speed and an engine speed by receiving detection signals from at least a vehicle speed sensor 62 and an engine speed sensor 64 for determining a driving state of the vehicle. Thus, the control circuit 60 can determine whether the vehicle is running or stopped.

Therefore, by controlling the rotation of the motor 86 by the control circuit 60, the rigidity of the second diaphragm 68 is located in the middle of the space between the concave portion 82A of the switching valve 82 and the concave portion 54 of the block 50. Low atmospheric conditions and switching valve 8
The second diaphragm 68 is located in the middle of the space between the second concave portion 82A and the concave portion 54 of the block 50 in a cut-off state in which the rigidity of the second diaphragm 68 is high. The state of the second diaphragm 68 is switched between the state and the state, and the second restriction passage 46 is substantially opened and closed.

Note that the passage length of the first restriction passage 52 is longer than the passage length of the second restriction passage 46, and the passage cross-sectional area of the first restriction passage 52 is larger than that of the second restriction passage 46. Is smaller than the cross-sectional area of the passage.

The rigidity of the first diaphragm 18 and the rigidity of the second diaphragm 68 are different from each other, and the rigidity of the second diaphragm 68 is higher than that of the first diaphragm 18.

Here, the liquid column resonance frequency in the restriction passage is determined by the size of the restriction passage and the rigidity of the diaphragm, and the liquid column resonance frequency in the second restriction passage 46 is changed by the second diaphragm 68. The value can be changed by changing the value of the stiffness.

Next, the operation of this embodiment will be described. When the engine of the vehicle (not shown) is started, the pressure in the intake manifold 92 becomes negative.

Accordingly, when vibration is transmitted from the engine to the support 24, the elastic body 22 is deformed, and as a result, the vibration is attenuated by the deformation of the elastic body 22, and the vibration is attenuated. Vibration is difficult to be transmitted to.

Further, the main liquid chamber 32 expands and contracts with the deformation of the elastic body 22, and a pressure change occurs in the main liquid chamber 32 and the liquid in the sub liquid chambers 34 and 70 communicating with the main liquid chamber 32. When the liquid flows in the restriction passages 46 and 52 between the liquid chambers, viscous resistance or the like is generated. Not only the deformation of the elastic body 22 but also the pressure change of the liquid, the liquid column resonance, the viscous resistance, etc. As a result, the vibration is attenuated, and the vibration is more difficult to be transmitted to the vehicle body side.

The specific operation will be described below. For example, when the vehicle runs, shake vibration occurs.

The control circuit 60 determines from the vehicle speed sensor 62 and the engine speed sensor 64 that shake vibration is occurring, and drives and rotates the motor 86 to rotate the valve body 84 of the switching valve 82 to the position shown in FIG. Then, the intake manifold 92 and the second air chamber 74 are communicated with each other, and the inside of the second air chamber 74 is brought into a negative pressure state.

As a result, as shown in FIG. 3, the second diaphragm 68 is completely sucked into the concave portion 82A of the switching valve 82 constituting the wall surface of the second air chamber 74, and is brought into close contact therewith, whereby the second sub liquid chamber 70 is formed. The expansion and contraction becomes impossible, and the second restriction passage 46 is substantially closed. Therefore, the liquid actively moves in the first restriction passage 52 and receives a passage resistance, or the liquid column resonates, so that the first restriction passage 52 causes the dynamic spring as shown in the characteristic curve C of FIG. The constant is reduced, high damping is ensured, and shake vibration is absorbed.

The dynamic spring constant in the region of the high-speed muffled sound generated in the high rotation region of the engine with the positive movement of the liquid in the first restriction passage 52 is also shown by the characteristic curve in FIG. As shown in FIG.

On the other hand, for example, when the vehicle stops, idle vibration occurs in which the vibration frequency is higher than the shake vibration. In this case, the first restriction passage 52 is clogged,
At this time, the control circuit 60 determines from the vehicle speed sensor 62 and the engine speed sensor 64 that idle vibration has occurred, and drives and rotates the motor 86 to switch the valve element 84 of the switching valve 82.
Is rotated to the position shown in FIG. 1 to allow the outside air to communicate with the second air chamber 74 so that the inside of the second air chamber 74 communicates with the atmosphere.

As a result, the inside of the second air chamber 74 is brought into the atmospheric state at the same pressure as the atmospheric pressure, and the second diaphragm 68 is separated from the recess 82A of the switching valve 82 as shown in FIG.
The second sub liquid chamber 70 is in a state in which it can expand and contract, and the liquid can move back and forth in the second restriction passage 46. As a result, the liquid resonates in the liquid column in the second restriction passage 46, the dynamic spring constant of the vibration isolator 10 is reduced as shown by the characteristic curve A in FIG. 4, and the idle vibration is absorbed.

On the other hand, if the accelerator pedal is slightly depressed while the vehicle is stopped, for example, the number of revolutions of the engine increases, and a low-speed muffled sound, which is a high idle vibration whose vibration frequency is higher than the normal idle vibration, is generated.

In this case as well, the first restriction passage 52 is clogged. At this time, the control circuit 60 determines from the vehicle speed sensor 62 and the engine speed sensor 64 that high idle vibration has occurred. The motor 86 is driven and rotated to rotate the valve body 84 of the switching valve 82 to the position shown in FIG.
The inside of the air chamber 74 is sealed.

As a result, the inside of the second air chamber 74 is cut off from the outside, and the second auxiliary liquid chamber 70 is in a state where it can be expanded and contracted. Liquid may be able to flow through the second restriction passage 46.

As a result, as described above, the second restriction passage 4
6, the liquid spring resonates in the liquid column, and the dynamic spring constant of the vibration isolator 10 is reduced. However, since the second air chamber 74 is closed, the rigidity of the second diaphragm 68 is increased. FIG.
As shown by the characteristic curve B, the resonance frequency of the second restriction passage 46 shifts to a higher side than the atmospheric state, and the high idle vibration is absorbed.

That is, the second air chamber 74 is communicated with the atmosphere through the switching valve 82 or the second air chamber 74 is connected to the switching valve 82.
And the second air chamber 7
4 are different from each other, and although the rigidity of the second diaphragm 68 is substantially different, the second diaphragm 68
Move freely, resonance of the liquid in the second restriction passage 46 can be generated corresponding to the two frequencies.

As described above, by switching the air pressure in the second air chamber 74 located opposite the second sub liquid chamber 70 and the second diaphragm 68 by the operation of the switching valve 82, vibrations having different frequencies are generated. Even when each is input to the vibration isolation device 10, it can correspond to each.

As a result, the switching valve 82 allows the second air chamber 74 to communicate with the atmosphere side, the air state that blocks the second air chamber 74 from the outside, and the second air chamber 74 to communicate with the intake manifold 92. Between the negative pressure state and the second
By switching the state of the air chamber 74, the characteristics of the vibration isolator 10 can be changed, and the vibration can be absorbed over a wide frequency range.

Next, a second embodiment of a vibration isolator according to the present invention is shown in FIG. 5, and the present embodiment will be described with reference to FIG. The same members as those described in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

As shown in FIG. 5, instead of a valve element 84 rotated by a motor 86, a switching valve 82 according to the present embodiment includes a plunger 102 having a small diameter portion 102A in part and this plunger 102. A coil 104 that moves up and down is built in.

For this reason, by adjusting the energization state of the coil 104, the atmosphere state in which the second air chamber 74 communicates with the atmosphere side, the shut-off state in which the second air chamber 74 is shut off from the outside, and the second air chamber 74 are controlled. The state of the second air chamber 74 can be switched between a state of a negative pressure and a state of communication with the intake manifold 92.

In the above-described embodiment, the configuration in which the vibration isolator 10 is used as an engine mount is shown. However, the present invention is not limited to this, and the vibration isolator 10 may be a cab mount, a body mount, a support for general industrial machines, or the like. Of course, it may be used.

Further, in the above embodiment, the support base 24 side is attached to the engine side which is the vibration generating section,
Although the bottom plate 12 side is attached to the vehicle body side which is the vibration receiving portion, the configuration may be reversed.

[0062]

As described above, the anti-vibration device of the present invention has an effect that vibration of a wide range of frequencies can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of an anti-vibration device according to a first embodiment of the present invention, showing an atmospheric state.

FIG. 2 is a cross-sectional view of the vibration isolator according to the first embodiment of the present invention, showing a shut-off state.

FIG. 3 is a sectional view of the vibration isolator according to the first embodiment of the present invention, showing a negative pressure state.

FIG. 4 is a graph showing a relationship between a dynamic spring constant and a frequency of the vibration isolator according to the first embodiment of the present invention.

FIG. 5 is a sectional view of a vibration isolator according to a second embodiment of the present invention.

FIG. 6 is a graph showing a relationship between a dynamic spring constant and a frequency of a conventional vibration isolator.

DESCRIPTION OF SYMBOLS 10 Vibration isolator 12 Bottom plate (first mounting member) 22 Elastic body 24 Support base (second mounting member) 32 Main liquid chamber 46 Second restriction passage 68 Second diaphragm 70 Second auxiliary liquid Chamber 74 Second air chamber 82 Switching valve

Claims (2)

[Claims] A first mounting member connected to one of the vibration generating section and the vibration receiving section; a second mounting member connected to the other of the vibration generating section and the vibration receiving section; and a first mounting member. An elastic body provided between the first mounting member and the second mounting member; a main liquid chamber in which the elastic body can be expanded and contracted by using the elastic body as a part of the partition wall and in which a liquid is sealed; and a main liquid chamber and an orifice. A sub-liquid chamber which is communicated through the sub-liquid chamber and which can be expanded and contracted; a deformable diaphragm which constitutes a part of a partition wall of the sub-liquid chamber; and air which is arranged opposite to the sub-liquid chamber with the diaphragm interposed therebetween and in which gas is sealed. And a valve that can be switched between an atmospheric state in which the air chamber communicates with the atmosphere side, a shutoff state in which the air chamber is isolated from the outside, and a negative pressure state in which the air chamber communicates with the intake source. Anti-vibration device. 2. The anti-vibration device according to claim 1, wherein the valve is connected to control means capable of detecting a running or stopped state of the vehicle, and the control means switches the valve.