JP4349098B2 - Anti-vibration support device - Google Patents

Description

  The present invention relates to a vibration isolating support device that supports vibration sources such as an internal combustion engine.

There is an anti-vibration support device as a device that reduces transmission of vibration generated by a vibration source such as an internal combustion engine to its support. Some anti-vibration support devices have an air spring function by providing an air chamber therein. For example, the anti-vibration support device described in Patent Document 1 has a heat resistance performance and an anti-resistance property even when a heat-resistant rubber material is used for the main rubber part by the action of an air spring provided by an air chamber provided inside the device. This makes it possible to achieve compatibility with the slack function.
JP-A-9-72373

The anti-vibration support device described in Patent Document 1 and the like is provided with an air chamber for acting as an air spring, but its spring characteristics remain constant regardless of the input vibration. Therefore, when the frequency of the resonance mode determined by such spring characteristics and the weight supported by the vibration isolating support device matches the frequency of vibration input to the vibration isolating support device, the resonance mode is There arises a problem that the vibration is amplified due to excitation.
Therefore, the present invention has been made in view of the above-described problems, and is provided with an air chamber provided in the vibration isolating support apparatus so as to have the function of an air spring and capable of preventing resonance mode excitation. The purpose is to provide.

In order to solve the above-described problem, the vibration isolating support device according to the present invention includes an input unit to which external vibration is input, and an air chamber whose volume changes according to the vibration input to the input unit. And a supporting means that opens and closes according to the amplitude of vibration input to the input unit, opens the air chamber to the outside when opened, and seals the air chamber when closed.
Further, in the vibration isolating support device according to the present invention, the valve includes an opening formed to be able to open the air chamber to the outside, and an insertion that is connected to the input portion at one end and is inserted into the opening. And a member.
In the vibration isolating support device according to the present invention, the insertion member is adjacent to the enlarged diameter portion and the enlarged diameter portion on one end side and the other end side of the insertion member, and the enlarged diameter portion is reduced in diameter. and reduced diameter portion, Ru rod member der which is formed.
Moreover, in the vibration isolating support device according to the present invention, the enlarged diameter portion has a cross-sectional shape capable of sealing the air chamber.
In the vibration isolating support device according to the present invention, the input unit is an inner cylinder disposed in an outer cylinder, and the air chamber is sealed with the inner cylinder and the outer cylinder as peripheral walls, and the opening The part is formed in the outer cylinder.
In the anti-vibration support device according to the present invention, the valve is configured such that the insertion member moves relative to the opening according to the displacement of the inner cylinder, and according to the increase in the displacement of the inner cylinder. Then, the portion of the insertion member located in the opening is switched from the enlarged diameter portion to the reduced diameter portion, thereby switching from closed to open.
Accordingly, switching between opening the air chamber to the outside and closing the air chamber according to the amplitude of vibration input to the input unit is performed. This switches between enabling and disabling the action of the air spring by the air chamber according to the amplitude of vibration input to the input unit.

According to the present invention, the input to the input unit is switched by switching between enabling and disabling the action of the air spring by the air chamber of the anti-vibration support means according to the amplitude of vibration input to the input unit. The spring characteristics of the vibration isolating support means can be changed according to the vibration amplitude.
Thereby, for example, the frequency of the resonance mode can be changed according to the amplitude of vibration input to the input unit.

The best mode for carrying out the present invention will be described in detail with reference to the drawings.
The first embodiment is an anti-vibration support device to which the present invention is applied.
As shown in FIG. 1, the internal combustion engine 1 is suspended by a vibration-proof support body 20. In order to suspend the internal combustion engine 1 on the vehicle body, the internal combustion engine 1 is provided with a bracket 2, and a vibration-proof support body 20 is interposed between the bracket 2 and the vehicle body 50. In FIG. 1, the anti-vibration support body 20 and the switching valve 40 constitute an anti-vibration support device.
FIG. 2 shows the configuration of the vibration isolating support body 20.
As shown in FIG. 2, the anti-vibration support main body 20 has a main body case 22 fixed to the vehicle body 50 via a bracket 21. The main body case 22 has a bottomed cylindrical shape. An elastic member 23 is fitted into the upper part inside the main body case 22. The elastic member 23 is an elastic body such as rubber.

An opening 22a is formed in the upper part of the main body case 22, and a connector 24 is attached to the elastic member 23 in the main body case 22 through the opening 22a. Here, the attachment 24 a of the connector 24 is attached to the elastic member 23. As described above, the connection tool 24 connected to the main body case 22 via the elastic member 23 is movably disposed on the upper portion of the main body case 22. The connector 24 is fixed to the internal combustion engine 1 side (bracket 2).
On the other hand, a buffer member 25 is filled in the bottom inside the main body case 22. The buffer member 25 is an elastic body such as rubber. In the main body case 22, first and second liquid chambers 26 and 27 are formed in a space between the elastic member 23 and the buffer member 25.

  The first and second liquid chambers 26 and 27 are formed by being divided into two upper and lower portions by a separating member 28 fitted inside the main body case 22, and the first and second liquid chambers 26 and 27 are formed in the first and second liquid chambers 26 and 27. Liquid such as oil is enclosed in the container. Here, the isolation member 28 is an elastic body such as rubber. Further, the first liquid chamber 26 and the second liquid chamber 27 are communicated with each other by a small-diameter passage (orifice) (not shown), whereby the liquid in the first and second liquid chambers 26 and 27 is the first liquid chamber 26 and the second liquid chamber 27. It is possible to move between the liquid chamber 26 and the second liquid chamber 27. A sheet-like diaphragm 29 is stretched on the upper surface of the separating member 28 that partitions the first and second liquid chambers 26 and 27.

The edge of the diaphragm 29 is fixed to the isolation member 28 by a fixture 30, and an air chamber 31 is formed between the diaphragm 29 and the upper surface of the isolation member 28.
A supply / discharge passage 32 is connected to the air chamber 31, and air is supplied / discharged through the supply / discharge passage 32.
As shown in FIG. 1, the vibration isolating support body 20 is connected to the intake pipe 11 connected to the internal combustion engine 1. Here, the intake pipe 11 forms a flow path that connects the air cleaner 12 and the throttle valve 13. Note that the pressure of the intake air flowing through the intake pipe 11 is substantially atmospheric pressure.

A switching valve 40 is disposed in the middle of the supply / discharge passage 32. Hereinafter, in the supply / discharge passage 32, a portion connecting the switching valve 40 and the vibration isolating support body 20 is referred to as a first supply / discharge passage 32a, and a portion connecting the switching valve 40 and the intake pipe 11 is a second supply / discharge passage. It is called 32b.
When the pressure in the air chamber 31 reaches a predetermined pressure, the switching valve 40 is in an open state and communicates with the first supply / discharge passage 32a and the second supply / discharge passage 32b. FIG. 3 shows the configuration of the switching valve 40.
As shown in FIG. 3, the switching valve 40 is provided with an isolation member 42 in a substantially cylindrical main body 41 so as to partition the first supply / discharge passage 32a and the second supply / discharge passage 32b. Yes. Hereinafter, in the main body 41, a portion 41a that is partitioned by the separating member 42 and forms the first supply / discharge passage 32a side is referred to as a first partition chamber 41a, and a portion that is partitioned by the separating member 42 and forms the second supply / discharge passage 32b side. 41b is referred to as a second partition 41b.

The isolation member 42 is fixed in the main body 41 by fixing the outer peripheral surface thereof to the inner peripheral surface of the main body 41. The isolation member 42 is formed with two first and second holes 42a and 42b.
An exhaust valve 43 is inserted into the first hole 42 a from the second partition chamber 41 b side, and the exhaust valve 43 is urged toward the isolation member 42 by support springs 45 and 46. The exhaust valve 43 has a substantially triangular pyramid shape, and the shape of the first hole 32 a is similar to the shape of the tip of the exhaust valve 43. Thereby, the outer peripheral surface of the front end portion of the exhaust valve 43 biased by the support springs 45 and 46 comes into close contact with the first hole 42a.

  An intake valve 44 is inserted into the second hole 42b from the first partition chamber 41a side, and the intake valve 44 is urged toward the isolation member 42 by support springs 47 and 48. The intake valve 44 has a substantially triangular pyramid shape, and the shape of the second hole 42 b is similar to the shape of the tip of the intake valve 44. Thereby, the outer peripheral surface of the front end portion of the intake valve 44 urged by the support springs 47 and 48 comes into close contact with the second hole 42b.

Here, each of the support springs 45 to 48 is set to a predetermined spring constant. Thus, when the differential pressure between the first partition chamber 41a and the second partition chamber 41b reaches a predetermined value, the exhaust valve 43 or the intake valve 44 is displaced against the biasing force of the support springs 45 to 48. Thus, the first partition chamber 41a and the second partition chamber 41b communicate with each other, whereby the first supply / discharge passage 32a and the second supply / discharge passage 32b communicate with each other.
The pressure in the first partition chamber 41a becomes the pressure in the first supply / discharge passage 32a, that is, the pressure in the air chamber 31. Further, the pressure in the second partition chamber 41b becomes the pressure in the second supply / discharge passage 32b, that is, the pressure in the intake pipe 11 (substantially atmospheric pressure).

Next, the operation of the anti-vibration support body 20 and the switching valve 40 constituting the anti-vibration support device will be described.
Engine vibration of the internal combustion engine 1 is input to the vibration isolation support body 20 through the connector 24. The elastic member 23 connected to the connector 24 is deformed by the input vibration. Further, due to the deformation of the elastic member 23, the volume of the first liquid chamber 26 formed on the upper side of the separating member 28 is changed, and the liquid filled in the first and second liquid chambers 26 and 27 is provided therebetween. You will come and go through small passages. At this time, the deformation of the volume of the second liquid chamber 27 is transmitted to the buffer member 25. Moreover, the pressure in the air chamber 31 fluctuates due to expansion and contraction of the elastic member 23, and this pressure fluctuation acts as an air spring. The action of the air spring by the air chamber 31 will be described in detail later.
As described above, when the engine vibration of the internal combustion engine 1 is input to the vibration isolating support body 20, the buffer member 25, the isolation member 28, the elastic member 23, and the like are deformed, and the vibration chambers 26 and 27 are placed in the liquid chambers 26 and 27, respectively. The filled liquid flows and the pressure in the air chamber 31 fluctuates. Through these various operations, engine vibration from the internal combustion engine 1 is reduced and transmitted to the vehicle body 50 via the bracket 21.

Next, the action of the air spring by the air chamber 31 will be described.
The elastic member 23 expands and contracts due to the vertical vibration of the connector 24 accompanying the vibration of the internal combustion engine 4, whereby the volume of the air chamber 31 varies. At this time, the pressure in the air chamber 31 decreases when the elastic member 23 is extended, and the pressure in the air chamber 31 increases when the elastic member 23 is compressed. Thus, when the pressure in the air chamber 31 fluctuates, the gate valve 40 operates as follows.
When the pressure in the air chamber 31 increases, the pressure in the first partition chamber 41a also increases, thereby generating a differential pressure between the pressure in the first partition chamber 41a and the pressure in the second partition chamber 41b. Further, when the differential pressure reaches a predetermined set pressure, the exhaust valve 43 is displaced against the urging force of the support springs 45 and 46. That is, the exhaust valve 43 is opened. In this case, the first partition chamber 41a and the second partition chamber 41b communicate with each other, whereby the air chamber 31 is released from the positive pressure state (pressurized state) to the atmospheric pressure. At this time, the intake valve 44 does not move.

  On the other hand, when the pressure in the air chamber 31 decreases, the pressure in the first partition chamber 41a also decreases, so that a differential pressure is generated between the pressure in the first partition chamber 41a and the pressure in the second partition chamber 41b. . Further, when the differential pressure reaches a predetermined set pressure, the intake valve 44 is displaced against the urging force of the support springs 47 and 48. That is, the intake valve 44 is opened. Thereby, the 1st partition chamber 41a and the 2nd partition chamber 41b are connected, Thereby, the air chamber 31 will be in the state open | released from the negative pressure state to atmospheric pressure. At this time, the exhaust valve 43 does not move.

  Further, when the internal pressure in the air chamber 31 increases but the differential pressure between the pressure in the first partition chamber 41a and the pressure in the second partition chamber 41b does not reach a predetermined set pressure, the support spring Since the exhaust valve 43 is not displaced against the urging force of 45 and 46, the first partition chamber 41a and the second partition chamber 41b do not communicate with each other. Maintained. Similarly, in the case where the pressure in the air chamber 31 decreases, but the differential pressure between the pressure in the first partition chamber 41a and the pressure in the second partition chamber 41b does not reach a predetermined set pressure. Since the intake valve 44 is not displaced against the urging force of the support springs 47 and 48, the first partition chamber 41a and the second partition chamber 41b do not communicate with each other. Sealed state is maintained.

With the above operation, if the pressure fluctuation in the air chamber 31 is within a predetermined pressure fluctuation, the gate valve 40 does not operate, so that the air chamber 31 is kept in a sealed state. At this time, the pressure fluctuation in the air chamber 31 acts as an air spring. As a result, the spring characteristics of the vibration isolating support device itself become hard (the spring constant increases).
On the other hand, when the pressure fluctuation in the air chamber 31 becomes larger than the predetermined pressure fluctuation, the gate valve 40 is operated, and the air chamber 31 is opened to the atmospheric pressure. In this case, the action of the air spring due to the pressure fluctuation in the air chamber 31 as described above does not occur, and as a result, the spring characteristic of the vibration isolating support device itself becomes soft (the spring constant becomes small).

  That is, the pressure in the air chamber 31 varies according to the vibration state of the internal combustion engine 1, and the gate valve 40 opens and closes according to the pressure variation. Is switched to open atmospheric pressure and the air chamber 31 is sealed. As a result, whether the function of the air spring by the air chamber 31 is enabled or disabled is switched according to the vibration level of the internal combustion engine 1, so that The characteristics, that is, the spring characteristics and the like change according to the vibration state of the internal combustion engine 1.

Next, the effect will be described.
Here, the engine vibration of the internal combustion engine 1 that is the object of vibration suppression by the vibration isolation support body 20 will be specifically described, and the effect of the present invention on the engine vibration will be described. Here, the case where the number of cylinders of the internal combustion engine 1 is four will be described.
The vibration generation force of the internal combustion engine includes a combustion vibration force resulting from a pressure fluctuation of combustion explosion and an inertial vibration force generated by the rotating object such as the piston 3 and the connecting rod 4 moving up and down. .

The pressure fluctuation caused by the combustion is transmitted to the crankshaft 5 through the piston 3 to generate torque fluctuation. At this time, since the engine block 6 receives a torque reaction force from the piston 3, the engine block 6 vibrates around the axis of the crankshaft 5. Such vibration of the internal combustion engine due to the combustion exciting force is called roll vibration of the internal combustion engine.
Further, the piston 3 moves up and down in the cylinder 7 under the force of combustion explosion as described above. At this time, a reciprocating inertia force is generated, and the engine block 6 receiving the reaction force vibrates in the axial direction (vertical direction) of the cylinder 7. Such a vibration of the internal combustion engine due to the reciprocating motion of the piston 3 is called an inertial excitation force (vertical vibration) of the internal combustion engine. In FIG. 1, reference numeral 14 denotes an exhaust pipe.

From this, it is clear that the roll vibration changes according to the output of the internal combustion engine, and that the vertical vibration changes according to the rotational speed of the internal combustion engine. . That is, the roll vibration and the vertical vibration of the internal combustion engine also change in accordance with the operating state of the internal combustion engine in which the output of the internal combustion engine and the rotation speed of the internal combustion engine change.
On the other hand, the vertical vibration increases in proportion to the square of the rotational speed of the crankshaft 5. For this reason, the vertical vibration has a relatively low vibration level in the low-rotation castle compared to the roll vibration, whereas it becomes a relatively large vibration level in the high-rotation range compared to the roll vibration. For this reason, it can be said that the vibration at the start of the internal combustion engine 1 is mainly composed of roll vibration.

  For example, the roll fixed value (the natural frequency of the roll vibration) is set by the weight of the internal combustion engine 1 and the spring constant (spring characteristic) of the vibration-proof support main body 20, and is usually set to about 10 Hz, for example. Thereby, when the vibration order passes the roll eigenvalue when the internal combustion engine 1 is started, that is, when the vibration frequency of the internal combustion engine 1 transits from a low value to a high value, The vibration of the internal combustion engine 1 is excited by the roll eigenvalue, and the vibration level of the internal combustion engine 1 becomes very large.

  However, such vibration of the internal combustion engine 1 is input to the anti-vibration support body 20 through the connector 24. The anti-vibration support body 20 has a spring characteristic that changes according to the vibration level of the internal combustion engine 1 as described above. Therefore, as described above, when the vibration of the internal combustion engine 1 is excited by the roll eigenvalue and the vibration level of the internal combustion engine 1 becomes very large, when the vibration level reaches a certain level, the spring of the anti-vibration support main body 20 The characteristic changes. Specifically, the spring characteristics are softened. As a result, since the excited roll eigenvalue changes, the roll fixed value and the vibration frequency of the internal combustion engine 1 become different values. As a result, excitation of vibration of the internal combustion engine 1 is suppressed.

As described above, when the vibration order passes the roll eigenvalue when the internal combustion engine 1 is started, the vibration of the internal combustion engine 1 is excited by the roll eigenvalue, and the vibration level of the internal combustion engine 1 becomes very high. By changing the roll fixed value, it is possible to suppress the vibration of the internal combustion engine 1 from being excited.
That is, when the vibration level input to the anti-vibration support body 20 exceeds a certain level due to resonance, the switching valve 40 configured to open and close in conjunction with the vibration causes the air in the air chamber 31 of the anti-vibration support body 20 to air. By disabling the function of the spring, the spring characteristic of the vibration-proof support body 20 is changed, thereby changing the roll fixing value and suppressing the vibration of the internal combustion engine 1 from being excited. Thereby, the vibration and noise which a passenger | crew feels at the time of starting of the internal combustion engine 1 can be reduced.

  Here, FIG. 4 shows an example of the relationship between the displacement of the vibration-proof support body 20 and the spring constant of the vibration-proof support body 20 in the compression process and the expansion process. In this example, in the compression process, when the pressure difference between the pressure in the first partition 41a and the pressure in the second partition 41b reaches a predetermined set value, the exhaust valve 43 is displaced in the switching valve 40 ( The case where it was set to the open state is shown.

  When the vibration isolating support body 20 is compressed and displaced by a predetermined amount, and the differential pressure between the pressure in the first partition 41a and the pressure in the second partition 41b reaches a predetermined set pressure, the exhaust valve 43 opens. It becomes a state. Thereby, the pressure in the air chamber 31 falls to atmospheric pressure. Thereby, the anti-vibration support main body 20 comes to be further displaced to the compression side. Then, this time, when the vibration isolating support body 20 starts to be displaced to the extension side, the exhaust valve 43 has already returned to the closed state, so that the pressure in the air chamber 31 becomes negative, and the first time The differential pressure between the pressure in the first partition 41a and the pressure in the second partition 41b reaches a predetermined set pressure. As a result, the intake valve 44 is opened. Thereby, the pressure in the air chamber 31 rises to atmospheric pressure. Thereafter, the vibration of the anti-vibration support main body 20 transitions to vibration in the amplitude region in the normal state.

As a result, the spring constant of the anti-vibration support main body 20 has different values in the compression process and the expansion process, and the spring constant K2 in the expansion process is smaller than the spring constant K1 in the normal state (the spring characteristics are soft). . Thereby, as shown in FIG. 5, the roll eigenvalue at the time of the extension process (when the spring characteristic is soft) becomes smaller than that at the normal time. In this way, by changing the roll eigenvalue during the expansion process, as described above, it is possible to suppress the excitation of the vibration of the internal combustion engine 1 caused by the roll eigenvalue.
Further, as described above, the switching valve 40 has a simple structure. For example, the switching valve 40 can be configured by a general-purpose product such as a 1-way valve. As a result, it is possible to realize a vibration isolating support apparatus to which the present invention is applied without significantly increasing the cost of the conventional vibration isolating support apparatus.

Next, a second embodiment will be described. The second embodiment is an anti-vibration support device to which the present invention is applied.
As shown in FIG. 6, the power unit 80 is suspended by suspension support devices 60FR, 60FL, 60RR, 60RL. In FIG. 6, the suspension support devices 60FR, 60FL, 60RR, 60RL are simply shown as spring structures, but actually, one of the suspension support devices 60FR, 60FL, 60RR, 60RL is shown in FIG. It is configured as shown. Further, in FIG. 6, reference numeral 91 denotes a subframe arranged at the lower part of the vehicle. The sub-frame 91 is a frame body formed of cross beam members. A power unit 80 is disposed on the subframe 91.

  The power unit 80 includes an internal combustion engine 81 and a transmission 82, and the transmission 82 is connected to the left side in the vehicle width direction with respect to the internal combustion engine 81. The power unit 80 is mounted on the subframe 91 by connecting a plurality of engine mounts such as the engine mounts 70A and 70B to the brackets 83 and 84 of the power unit 80. Here, the internal combustion engine 81 is a horizontal type internal combustion engine. The engine mounts 70A and 70B are ordinary rubber bushes or the like.

  In addition, four suspension support devices 60FR, 60FL, 60RR, and 60RL are disposed at each corner portion of the subframe 91. Here, the suspension support devices 60FR and 60FL are disposed in the front portion of the subframe 91, and the remaining two suspension support devices 60RR and 60RL are disposed in the rear portion of the subframe 91. The subframe 91 is supported by a vehicle body (not shown) via these suspension support devices 60FR, 60FL, 60RR, 60RL.

At least one of the suspension support devices 60FR, 60FL, 60RR, 60RL has a structure as shown in FIG. Here, among the suspension support devices 60FR, 60FL, 60RR, and 60RL, one having a structure as shown in FIG. 7 is referred to as a suspension support device 60, and the structure will be described below.
In FIG. 7, a suspension support device 60 is configured as a vibration isolation support device to which the present invention is applied. In the first embodiment described above, the anti-vibration support main body 20 and the switching valve 40 are separate components, and the anti-vibration support device is constituted by these. In this second embodiment, the suspension support is provided. The device 60 itself includes a switching valve 66, and the rack support device 60 itself constitutes a vibration isolating support device to which the present invention is applied.

The suspension support device 60 has a cylindrical shape, and FIG. 7 shows a cross-sectional structure of the suspension support device 60. As shown in FIG. 7, the suspension support device 60 includes an outer cylinder 61 and an inner cylinder 62 disposed substantially at the center of the outer cylinder portion.
The outer cylinder 61 is attached to the subframe 91 via a bracket or the like. For example, the outer cylinder 61 is a metal cylindrical body. On the other hand, the inner cylinder 62 is fixed to a vehicle body (not shown). The inner cylinder 62 is a metal cylinder having a relatively large thickness.

  An elastic member 63 is disposed between the outer cylinder 61 and the inner cylinder 62. The elastic member 63 includes a cylindrical portion 63a that is shaped to cover the outer periphery of the inner cylinder 62, and a main body portion 63b that is integrated with the cylindrical portion 63a and is formed in a substantially fan shape so as to face each other. Has been. In the elastic member 63, the inner peripheral surface of the cylindrical portion 63a is vulcanized and bonded to the outer peripheral surface of the inner cylinder 62, and the outer peripheral surface of the main body portion 63b is vulcanized and bonded to the inner peripheral surface of the outer cylinder 61.

With such a configuration, when the inner cylinder 62 moves in the direction perpendicular to the plane of FIG. 7, the elastic member 63 is deformed according to the movement, and an elastic force according to the deformation acts on the inner cylinder 62. .
By forming the elastic member 63 as described above, the elastic member 63 and the outer cylinder 61 form air chambers 64a and 64b. That is, air chambers 64a and 64b having the outer cylinder 61 as an outer wall are formed. The air chambers 64a and 64b are communicated with each other through a flow path not shown.

An opening 65 is formed in a part of the outer cylinder 61 forming the outer wall of the air chambers 64a and 64b so as to communicate the air chambers 64a and 64b with the outside (atmospheric pressure portion). The opening 65 is formed at, for example, the lower part of the air chambers 64a and 64b (lower part of the outer cylinder 61).
A switching valve 66 is inserted into the air chamber 64 b through the opening 65. The switching valve 66 is a rod-shaped body having a substantially circular cross section arranged in the radial direction of the inner cylinder 62, and one end 66 a thereof is fixed to the inner cylinder 62 or the cylindrical portion 63 a of the elastic member 63, and the other end is Projecting from the outer cylinder 61. In the normal state, that is, in the state where no load is applied to the suspension support device 60, the intermediate portion 66 b of the switching valve 66 is positioned in the opening 65. The intermediate portion 66b, that is, a certain region before and after the portion located in the opening 65 has a larger shaft diameter than the other portions (end portions) 66a and 66c.

Further, the opening 65 is provided with a seal member 67 so as to be adapted to the outer diameter of the intermediate portion 66b of the switching valve 66. That is, in the normal state, the opening member 65 is provided with a seal member 67 that is in close contact with the outer periphery of the intermediate portion 66b of the switching valve 66. Thus, in the normal state, the air chambers 64a and 64b are substantially sealed . Will be kept.

Next, the operation of the suspension support device 60 and the switching valve 66 provided in the suspension support device 60 will be described.
The vibration of the power unit 80 is input to the suspension support device 60 through the outer cylinder 61. The elastic member 63 connected to the outer cylinder 61 is deformed by the input vibration. Further, the volume of the air chambers 64 a and 64 b changes due to the deformation of the elastic member 63. On the other hand, according to the displacement of the inner cylinder 62, the switching valve 66 having one end 66a fixed to the inner cylinder 62 fluctuates (vibrates) in the front-rear direction (vertical direction in FIG. 7) with respect to the opening 65. At this time, as long as the intermediate portion 66b is positioned in the opening 65, the air chambers 64a and 64b are maintained in a substantially sealed state. Thereby, the pressure fluctuation in the air chambers 64a and 64b acts as an air spring.

As described above, when the vibration of the power unit 80 is input via the subframe 91, the suspension support device 60 deforms the elastic member 63 or the pressure in the air chambers 64a and 64b fluctuates. Through such operations, vibration from the power unit 80 is reduced and transmitted to the vehicle body.
Here, as described above, when vibration of the power unit 80 is input to the suspension support device 60, the inner cylinder 62 vibrates, so that the gate valve 66 varies in the front-rear direction with respect to the opening 65. At this time, as long as the intermediate portion 66b is positioned in the opening 65, the air chambers 64a and 64b are kept in a substantially sealed state so that the pressure fluctuation in the air chambers 64a and 64b acts as an air spring. become.

  However, if the vibration of the power unit 80 exceeds a certain level, that is, if the vibration of the inner cylinder 62 exceeds a certain level, the air chambers 64a and 64b are not kept in a sealed state, and the action of the air spring by the air chambers 64a and 64b is caused. Disappear. That is, when the vibration of the inner cylinder 62 exceeds a certain level, the moving amount of the switching valve 66 with respect to the opening 65 increases, and the end portion (reduced diameter portion) of the switching valve 66 is positioned in the opening 65. Become. When the end portion (reduced diameter portion) of the switching valve 66 is positioned in the opening 65, a gap is formed between the opening 65 (specifically, the seal member 67) and the switching valve 66, and thus the air chamber 64a. 64b is not maintained, and the air chambers 64a and 64b are opened to atmospheric pressure. Thereby, the action of the air spring by the air chambers 64a and 64b is eliminated. In this case, the spring characteristic of the suspension support device 60 becomes soft.

  That is, the pressure in the air chambers 64 a and 64 b varies according to the vibration state of the power unit 80, and the gate valve 66 opens and closes according to the pressure variation. Switching between opening of the atmospheric pressures 64a and 64b and closing of the air chambers 64a and 64b is switched. As a result, since the function of the air spring by the air chambers 64a and 64b is enabled and disabled depending on the vibration level of the power unit 80, the suspension support device 60 can be used as a buffer unit. The characteristics, that is, the spring characteristics and the like change according to the vibration state of the power unit 80.

Next, the effect will be described.
Here, the vibration of the power unit 80 that is the object of vibration suppression by the suspension support device 60 will be specifically described, and the effect of the present invention on the vibration will be described.
When the power unit 80 composed of the internal combustion engine 81 and the transmission 82 is supported by the subframe 91, six types of resonance modes are generated in the subframe 91. Among them, there are three types of resonance modes: bounce resonance mode, pitch resonance mode, and roll resonance mode, which have the highest sensitivity input to the vehicle body and may cause discomfort to passengers in the passenger compartment. Mode. As shown in FIG. 8A, the bounce resonance mode is a resonance mode in which the subframe 91 moves in the vertical direction. Further, the pitch resonance mode is a resonance mode in which the sub-frame 91 rotates around the pitch axis in the vehicle left-right direction, as shown in FIG. Further, the roll resonance mode is a resonance mode in which the subframe 91 rotates around the roll axis in the vehicle front-rear direction, as shown in FIG.

  The frequency of these resonance modes is mainly determined by the weight of the subframe 91 and the spring constants of the suspension support devices 60FR, 60FL, 60RR, 60RL. When the frequency of the resonance mode of the sub-frame 91 matches the frequency generated by the power unit 80, the resonance mode of the sub-frame 91 is excited and the vibration level input to the suspension support devices 60FR, 60FL, 60RR, 60RL is also Become very large.

  At this time, such vibration of the subframe 91 is input to the suspension support device 60 to which the present invention is applied, among the suspension support devices 60FR, 60FL, 60RR, and 60RL. At this time, the suspension support device 60 has its spring characteristics changed according to the vibration level of the subframe 91 as described above. Therefore, as described above, when the resonance mode of the sub-frame 91 is excited and the vibration level of the sub-frame 91 becomes very large, the spring characteristics of the suspension support device 60 change when the vibration level reaches a certain level. . Specifically, the spring characteristics are softened. As a result, the frequency of the resonance mode of the excited subframe 91 changes, so that the frequency of the resonance mode and the frequency of the power unit 80 are different from each other. As a result, the vibration of the subframe 91 is excited. Will be suppressed. Thereby, it can suppress that the vibration of the power unit 80 is transmitted to a vehicle body, and it can eliminate or reduce that a noise and a vibration make a passenger | crew unpleasant.

In addition, when the vibration level input to the suspension support device 60 is small, the air chambers 64a and 64b of the suspension support device 60 are maintained in a sealed state, and therefore the suspension support device 60 may have a function as an air spring. it can. At this time, the spring constant of the suspension support device 60 itself is a value obtained by synthesizing the elastic member 63 and the air spring, and the suspension support device 60 can perform a normal vibration isolation function with the spring constant based on the value. .
Here, FIG. 9 shows an example of the relationship between the displacement of the suspension support device 60 and the spring constant of the suspension support device 60.

  When the suspension support device 60 is compressed or expanded and displaced by a predetermined amount, the pressure in the air chambers 64a and 64b becomes atmospheric pressure. As a result, as shown in FIG. 9, the spring constant of the suspension support device 60 becomes a large spring constant K1 when the displacement amount is small, and becomes a small spring constant K2 when the displacement amount is large (the spring characteristic becomes soft). As a result, when the vibration level becomes higher than a predetermined vibration level, the resonance mode frequency of the subframe 91 is changed by changing the spring constant of the suspension support device 60, and is generated due to the frequency of the resonance mode. The excitation of the vibration of the subframe 91 to be performed can be suppressed.

The embodiment of the present invention has been described above. However, the present invention is not limited to being realized as the above-described embodiment.
That is, in the first embodiment described above, when the pressure in the air chamber 31 reaches a predetermined pressure, the switching valve 40 is opened. In the second embodiment described above, the inner cylinder When 62 is displaced by a predetermined amount, the switching valve 66 is opened, but these configurations may be incorporated in one vibration-proof support device. Thereby, the spring characteristic of the suspension support device can be made variable based on the pressure fluctuation in the air chamber 31 and the fluctuation of the input vibration itself.

In the first embodiment described above, the case where the external pressure for opening the air chamber is atmospheric pressure or substantially atmospheric pressure has been described. However, it goes without saying that the present invention is not limited to this. That is, since the switching valve 40 operates as long as there is a differential pressure between the pressure in the air chamber 31 and the external pressure, the external pressure may be lower or higher than the atmospheric pressure.
For example, if the external pressure is lowered, the air from the air chamber can smoothly flow out to the outside when the switching valve is opened, and the function of the air spring can be quickly eliminated. That is, the spring characteristic can be changed promptly and the resonance frequency can be quickly shifted. Also, if the external pressure is increased, specifically, when the switching valve is open, high-pressure air is sent to the air chamber, and when the switching valve is subsequently closed, the high-pressure air is activated. A fluid air spring can be realized. Thereby, an air spring having a large spring constant can be realized.

  In the second embodiment described above, the case has been described in which at least one of the suspension support devices 60FR, 60FL, 60RR, 60RL is the suspension support device 60 to which the present invention is applied. However, it goes without saying that the present invention is not limited to this. That is, two or more of the suspension support devices 60FR, 60FL, 60RR, and 60RL, or all of the suspension support devices 60FR, 60FL, 60RR, and 60RL may be configured as the suspension support device 60 to which the present invention is applied.

  In the above-described embodiment, the connector 24 and the inner cylinder 62 constitute an input unit to which external vibration is input, and the air chamber 31 or the air chambers 64a and 64b are input to the input unit. An air chamber whose volume changes in response to vibration is configured, and the switching valve 40 or the switching valve 66 and the opening 65 open the air chamber to the outside when opened, and seal the air chamber when closed. The structure that operates the switching valve 40 by the air chamber 31 and the structure that operates the switching valve 66 by the displacement of the inner cylinder 62 includes the valve according to the amplitude of vibration input to the input unit. Switching means for switching between opening and closing is configured.

It is sectional drawing which shows the state in which the anti-vibration support apparatus of the 1st Embodiment of this invention is supporting the internal combustion engine. It is sectional drawing which shows the structure of the suspension support apparatus with which the said vibration proof support apparatus is provided. It is sectional drawing which shows the structure of the switching valve with which the said vibration proof support apparatus is provided. It is a characteristic view which shows the relationship between the displacement of the said suspension support apparatus, and the spring constant of the said suspension support apparatus. It is a characteristic view which consists of the relationship between a frequency and transmission force used for explanation that the spring characteristic of a suspension support device changes by the operation of a switching valve, and thereby the roll eigenvalue changes. It is a perspective view which shows the state which the vibration isolating support apparatus of the 2nd Embodiment of this invention is supporting the power unit. It is sectional drawing which shows the structure of the suspension support apparatus with which the anti-vibration support apparatus of the said 2nd Embodiment is provided. It is the figure used for description of the resonance mode which generate | occur | produces in a sub-frame, (A) in the figure is a perspective view which shows a bounce resonance mode, (B) is a side view which shows a pitch resonance mode, (C) is a front view showing a roll resonance mode. It is a characteristic view which shows the relationship between the displacement of the suspension support apparatus in the said 2nd Embodiment, and the spring constant of the said suspension support apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,81 Internal combustion engine 20 Anti-vibration support main body 23, 63 Elastic member 24 Connector 31, 64a, 64b Air chamber 32 Supply / exhaust passage 40, 66 Switching valve 60 Suspension support device 62 Inner cylinder 80 Power unit 82 Transmission

Claims (3)

Support means comprising an input unit to which vibration from the outside is input, and an air chamber whose volume changes according to the vibration input to the input unit;
A valve that opens and closes according to the amplitude of vibration input to the input unit, opens the air chamber to the outside when opened, and seals the air chamber when closed.
The valve has an opening formed to be able to open the air chamber to the outside, and an insertion member that is connected to the input portion at one end and is inserted into the opening.
The insertion member is a rod-shaped member formed with an enlarged diameter portion and a reduced diameter portion which is adjacent to the enlarged diameter portion on one end side and the other end side of the insertion member and which has a reduced diameter. Yes,
The enlarged diameter portion has a cross-sectional shape capable of sealing the air chamber,
The input unit is an inner cylinder disposed in an outer cylinder,
The air chamber is sealed with the inner cylinder and the outer cylinder as peripheral walls,
The opening is formed in the outer cylinder,
The valve is configured such that the insertion member moves relative to the opening in accordance with the displacement of the inner cylinder , and is positioned in the opening in the insertion member in accordance with an increase in the displacement of the inner cylinder. The anti-vibration support device is switched from closed to open by switching from the enlarged diameter portion to the reduced diameter portion. The enlarged-diameter portion has a partial section located in the opening in a state in which no vibration is input to the input portion, and the one end side and the other end side of the insertion member extend beyond the opening portion. And
The length of the reduced diameter portion formed adjacent to the enlarged diameter portion on one end side of the insertion member is the length of the reduced diameter portion formed adjacent to the enlarged diameter portion on the other end side of the insertion member. The vibration-proof support device according to claim 1, wherein the vibration-proof support device is equal to or greater than The anti-vibration support device according to claim 1 or 2 , wherein the valve is switched from closed to open according to the occurrence of resonance caused by vibration of a vibration source.

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