JP3641024B2 - Vibration isolator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vibration isolator that is used in vehicles, general industrial machines, and the like and absorbs and attenuates vibration from a vibration generating unit.
[0002]
[Prior art]
A vibration isolator as an engine mount is disposed between the engine and the vehicle body of the automobile so as to prevent the vibration of the engine from being transmitted to the vehicle body.
[0003]
The vibration generated in the engine includes so-called shake vibration that occurs when the vehicle is traveling at high speed, and so-called idle vibration that occurs when the vehicle is idling and when the vehicle is traveling at about 5 km / h. . In general, the frequency of the shake vibration is less than 15 Hz, whereas the frequency of the idle vibration is 20 to 50 Hz. The frequency is different between the shake vibration and the idle vibration.
[0004]
And as a vibration isolator that absorbs shake vibration and idle vibration, the main liquid chamber and the sub liquid chamber are connected by an orifice that is a restriction passage, and the liquid sealing that reduces the vibration by the damping action accompanying the flow of the liquid in the orifice A vibration isolator of the type is known. In addition, as one type of such a vibration isolator, the characteristics can be changed by changing the air pressure in the air chamber arranged opposite to the auxiliary liquid chamber via the diaphragm with a switching valve that is an electromagnetic valve. Anti-vibration devices have been proposed.
[0005]
[Problems to be solved by the invention]
However, when a vibration isolator having such a switching valve is fixed in, for example, an automobile engine room, shock vibration generated by the plunger in the switching valve coming into contact with the inside of the valve causes the vehicle body of the automobile to move. There is a drawback of being transmitted through the vehicle interior.
[0006]
An object of the present invention is to provide an anti-vibration device capable of reducing shock vibration generated with opening and closing of a switching valve in order to solve the above-mentioned drawbacks in consideration of the above facts.
[0007]
[Means for Solving the Problems]
The vibration isolator according to claim 1 is a first attachment member connected to one of the vibration generating unit and the vibration receiving unit;
A second attachment member coupled to the other of the vibration generating portion and the vibration receiving portion;
An elastic body provided between the first mounting member and the second mounting member and deformed when vibration occurs;
A main liquid chamber in which the elastic body can be expanded and contracted as a part of a partition wall and a liquid is enclosed;
A secondary liquid chamber communicated with the main liquid chamber via a restriction passage;
A deformable diaphragm constituting a part of the partition wall of the sub liquid chamber;
An air chamber disposed opposite to the sub liquid chamber and the diaphragm and in which a gas is enclosed;
An open state in which the air chamber communicates with the atmosphere and a closure that closes the air chamber and the atmosphere, and is connected to the first attachment member or the second attachment member via an elastic member that can be elastically deformed. A switching valve that can take a state;
It is provided with.
[0008]
The operation of the vibration isolator according to claim 1 will be described below.
The vibration from the vibration generating unit 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 is also absorbed by the passage resistance of the liquid flowing through the restriction passage or the liquid column resonance by expanding and contracting the main liquid chamber using the elastic body as a part of the partition wall. The
[0009]
In this restricted passage, when high-frequency vibration that cannot be absorbed occurs, that is, when a preset set frequency is exceeded, the air chamber and the atmosphere that are located opposite to each other across the diaphragm and the diaphragm Is closed by a switching valve. If it does in this way, the rigidity of a diaphragm will increase rather than the case where the air in an air chamber acts as an air spring, and the switching valve is open | released and it is made the open state which connects between an air chamber and air | atmosphere. As a result, the frequency at which the liquid resonates in the restricted passage moves to the high frequency side, and the dynamic spring constant of the vibration isolator decreases in the frequency region of high frequency vibration.
[0010]
That is, the characteristics of the vibration isolator can be changed by the switching valve depending on whether the air chamber is opened to the atmosphere, and vibration can be absorbed over a wide frequency range.
[0011]
On the other hand, since the switching valve is connected to either the first mounting member or the second mounting member via an elastic member that can be elastically deformed, when the switching valve is switched between the open state and the closed state. Even if the plunger, which is the valve body in the switching valve, comes into contact with the valve body of the switching valve to generate shocking vibration, it is absorbed and reduced by the resistance based on the internal friction of the elastic member.
[0012]
Therefore, when a vibration isolator having such a switching valve is fixed in, for example, an engine room of an automobile, vibration associated with the contact of the plunger with the valve body is not transmitted to the vehicle interior via the automobile body. It becomes like this.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of a vibration isolator according to the present invention is shown in FIG. 1 to FIG. 4, and this embodiment will be described based on these drawings.
[0014]
As shown in FIG. 1, the vibration isolator 10 of the present embodiment is provided with a bottom plate 12 as a first attachment member. A mounting bolt 14 projects from the bottom lower portion of the bottom plate 12 and, as an example, the vibration isolator 10 is fixed to a vehicle body (not shown) using the mounting bolt 14. The periphery of the bottom plate 12 is a cylindrical standing wall portion 12A bent at a right angle, and a flange portion 12B bent at a right angle is continuously formed at the upper end portion of the standing wall portion 12A.
[0015]
On the bottom plate 12, an outer cylinder 16 having a thick cylindrical shape and a part of the lower portion being thin is disposed. Further, the peripheral edge portion of the first diaphragm 18 is sandwiched between the flange portion 12 </ b> B of the bottom plate 12 and the lower end portion of the thick portion of the outer cylinder 16, and is caulked and fixed by the thin portion of the outer cylinder 16.
[0016]
A 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 21 formed in the standing wall portion 12A.
[0017]
The upper end portion of the inner peripheral surface of the outer cylinder 16 is an expanded portion 16A whose inner diameter is enlarged in a tapered shape, and the outer periphery of the elastic body 22 that closes the opening portion of the outer cylinder 16 is formed in the expanded portion 16A. It is vulcanized and bonded. A part of the elastic body 22 extends to the lower end of the inner periphery of the outer cylinder 16, and the outer peripheral side of the elastic body 22 is vulcanized and bonded to the outer cylinder 16.
[0018]
A support base 24 as a second mounting member is vulcanized and bonded to the center of the elastic body 22. The support 24 is an engine mounting portion (not shown), and mounting bolts 26 for fixing the engine are provided upright.
[0019]
A liquid chamber 28 is formed here by the inner peripheral portion of the outer cylinder 16, the lower end portion of the elastic body 22, the first diaphragm 18, and the like, and the liquid chamber 28 is filled with a liquid such as ethylene glycol.
[0020]
A cylindrical partition member 30 formed of synthetic resin or the like is disposed in the liquid chamber 28, and a flange 30 </ b> A that protrudes to the outer peripheral side is provided at the lower part of the partition member 30. The flange 30 </ b> A is sandwiched between the peripheral edge portion of the first diaphragm 18 and the lower end portion of the thick portion of the outer cylinder 16.
[0021]
Therefore, the partition member 30 divides the liquid chamber 28 into a main liquid chamber 32 and a first sub liquid chamber 34. A recess 30 </ b> B is formed on the partition member 30 on the first sub liquid chamber 34 side.
[0022]
On the outer periphery of the partition member 30, a narrow groove 44A having a rectangular cross section is formed along the circumferential direction. A narrow groove 44B extending to the upper surface of the partition member 30 is connected to one end of the narrow groove 44A, and an opening 44C penetrating to the recess 30B is connected to the other end of the narrow groove 44A. The narrow grooves 44 </ b> A and 44 </ b> B are closed on the outer cylinder 16 side by an extension of the elastic body 22, and serve as a first restriction passage 52 that communicates between the main liquid chamber 32 and the first sub liquid chamber 34.
[0023]
Furthermore, a rectangular hole 42 is formed in the partition member 30 from the outer periphery toward the center of the partition member 30, and as shown in FIG. 1, the tip of the rectangular hole 42 is bent upward to open the opening 42 </ b> A. The second restriction passage 46 is configured to communicate with the main liquid chamber 32 through the second restriction passage 46.
[0024]
A concave portion 62 is formed at a position on the outer peripheral side of the outer cylinder 16 corresponding to the rectangular hole 42 of the partition member 30, and the concave portion 62 is closed by a block 64 that is closely fitted and fixed to the concave portion 62. Has been. A through hole 72 is formed at the bottom of the recess 62, and the through hole 72 communicates with the rectangular hole 42.
[0025]
An annular recess 66 is formed at the bottom of the recess 62 and on the outer peripheral side of the through hole 72, and the peripheral edge of the second diaphragm 68 is sandwiched between the annular recess 66 and the block 64. . The second diaphragm 68 protrudes in a substantially hemispherical shape toward the through hole 72 in a free state, and the through hole 72 is closed by the second diaphragm 68 to form the second sub liquid chamber 70. A recess 64A is formed on one end of the block 64 facing the second diaphragm 68, and a space between the recess 64A and the second diaphragm 68 is a second air chamber 74.
[0026]
The other end side of the block 64 is vulcanized and bonded to the base end side of a cylindrical support material 112 formed of an elastic member such as a rubber material that can be elastically deformed. The distal end side of the support material 112 is vulcanized and bonded to a metal connecting plate 114 having a hole 114A.
[0027]
Further, a connecting pipe 80 is disposed adjacent to the connecting plate 114, and a flange portion 80 </ b> A that protrudes toward the outer peripheral side is provided near the base end side of the connecting pipe 80. A male screw 80B is formed on the tip side. Then, the male screw 80B on the distal end side of the connecting pipe 80 is screwed to a main body 82A that is a valve body of the switching valve 82 as shown in FIGS. 1 to 3, and the connecting pipe 80 and the switching valve 82 are connected. Yes. Further, the flange portion 80A of the connecting pipe 80 is screwed to the connecting plate 114 with the bolt 116 in a state where the base end side of the connecting pipe 80 is fitted in the through hole 114A of the connecting plate 114, thereby the connecting pipe 80. Is connected to the outer cylinder 16 via the support member 112 and the block 64.
[0028]
As described above, the switching valve 82 is connected to and supported by the outer cylinder 16 through the connecting pipe 80 and the support member 112 screwed to the switching valve 82, and the second air chamber 74 and the switching valve 82 described above are supported. The holes 64 </ b> B formed in the block 64, the space in the support material 112, and the connection pipe 80 are communicated with each other.
[0029]
On the other hand, a coil housing body 90 housing a coil 84 is connected to the main body 82 </ b> A of the switching valve 82 through a tube 88. A plunger 86 that is a valve body is movably disposed in the tube 88, and a spring 92 is disposed between the proximal end side of the plunger 86 and the suction element 96 installed in the coil storage body 90. Has been placed. A packing 86A is attached to the distal end side of the plunger 86, and passes through the block 64, the support member 112, the connecting pipe 80, and the main body 82A of the switching valve 82 to communicate the second air chamber 74 and the atmosphere. The L-shaped passage 94 can be blocked by the packing 86A.
[0030]
Therefore, when no voltage is applied to the coil 84, as shown in FIG. 2, the plunger 86 is urged by the spring 92 and the packing 86A comes into contact with the inner wall surface of the main body 82A. Occlude. On the other hand, when a predetermined voltage is applied to the coil 84, as shown in FIG. 3, the plunger 86 is attracted to the attractor 96 side by the electromagnetic force generated by the coil 84, and the packing 86A at the tip of the plunger 86 is inside the main body 82A. The passage 94 is opened by running away from the wall surface.
[0031]
The coil 84 is connected to a control circuit 60 that is a control means for turning on and off the applied voltage. The control circuit 60 is driven by a vehicle power source, and can detect the vehicle speed and the engine speed by receiving at least detection signals from the vehicle speed sensor 98 and the engine speed sensor 99. As a result, the control circuit 60 can determine whether the vehicle is idling or shaking, and whether the vibration frequency is lower or higher in the idle vibration.
[0032]
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 longer than the passage restriction of the second restriction passage 46. It is smaller than the area. Further, the rigidity of the first diaphragm 18 and the second diaphragm 68 is different from each other, and the rigidity of the second diaphragm 68 is higher than that of the first diaphragm 18.
[0033]
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 determined as the rigidity value of the second diaphragm 68. It can be changed by changing.
[0034]
On the other hand, a recess 100 is formed in the center of the partition member 30 on the main liquid chamber 32 side, and an elastic membrane fixing pipe 102 is inserted and fixed in the recess 100.
[0035]
On the inner peripheral surface of the elastic membrane fixing pipe 102, the outer periphery of a rubber elastic membrane 104 made of a disk is vulcanized and bonded at the axially intermediate portion, and a space between the elastic membrane 104 and the bottom of the recess 100 is formed. The gas chamber 106 is filled with a gas such as air. That is, the gas chamber 106 is disposed opposite to the main liquid chamber 32 with the elastic film 104 interposed therebetween. The gas chamber 106 is not in communication with the atmosphere.
[0036]
In the present embodiment, the rigidity of the elastic film 104 is higher than that of the first diaphragm 18 and the second diaphragm 68.
[0037]
Next, the operation of the embodiment will be described.
When the bottom plate 12 of the vibration isolator 10 is fixed to a vehicle body such as an automobile as an example and the engine is mounted on the support base 24 and fixed, the vibration of the engine is transmitted to the elastic body 22 via the support base 24, The vibration is absorbed by the resistance based on the internal friction of the elastic body 22.
[0038]
Further, when the vehicle travels at, for example, 70 to 80 km / h, shake vibration (for example, frequency less than 15 Hz) may occur. At this time, the liquid goes back and forth between the main liquid chamber 32 and the first sub liquid chamber 34 through the first restriction passage 52, and the damping force due to the resistance when the liquid passes through the first restriction passage 52. And shake vibration is effectively absorbed. In shake vibration, the highly rigid second diaphragm 68 is hardly deformed, and almost no liquid flows in the second restricting passage 46.
[0039]
Further, when the engine is idling, or when the vehicle speed is 5 km / h or less, idle vibration (for example, frequency 20 to 50 Hz) occurs.
[0040]
During this idle vibration, the first restriction passage 52 is clogged. For this reason, the liquid goes back and forth between the main liquid chamber 32 and the second sub liquid chamber 70 through the second restriction passage 46, and undergoes liquid column resonance in the second restriction passage 46. In idle vibration, since the liquid flows through the second restriction passage 46, the highly rigid elastic film 104 is hardly deformed.
[0041]
Here, the control circuit 60 determines whether the vibration frequency is the lower or the higher of the idle vibrations by the vehicle speed sensor 98 and the engine speed sensor 99. If it is determined that the vibration frequency is lower, the control circuit 60 applies a voltage to the coil 84 of the switching valve 82 to attract the plunger 86. As a result, the plunger 86 is separated from the inner wall surface of the main body 82 </ b> A, and an open state is established in which the second air chamber 74 communicates with the atmosphere via the passage 94. As a result, the rigidity of the second diaphragm 68 is lower than that in the closed state in which the second air chamber 74 is closed, and the dynamic spring constant of the vibration isolator 10 in the frequency region of low frequency idle vibration is reduced. , Idle vibration with low frequency is reliably absorbed.
[0042]
On the other hand, if it is determined that the vibration frequency is the higher of the idle vibrations, the control circuit 60 stops applying the voltage to the coil 84. As a result, the plunger 86 is urged by the spring 92, the plunger 86 abuts against the inner wall surface of the main body 82A to close the passage 94, and the second air chamber 74 is closed to the atmosphere side. . For this reason, the rigidity of the second diaphragm 68 is increased, whereby the liquid column resonance frequency in the second restriction passage 46 moves to the high frequency side, and the vibration isolator 10 operates in the frequency region of high frequency idle vibration. The spring constant is reduced, and idling vibration with a high frequency is reliably absorbed.
[0043]
As described above, in the vibration isolator 10 of the present embodiment, both the low frequency idle vibration and the high frequency idle vibration are supported depending on whether or not the second air chamber 74 is opened to the atmosphere by the switching valve 82. it can.
[0044]
In addition, when the vehicle speed is 100 km / h or more and the engine speed is 3000 rpm or more, high-frequency vibration (for example, a frequency around 50 to 300 Hz) that causes a booming noise occurs.
[0045]
In this case, the second restricting passage 46 is clogged, but the elastic film 104 is deformed to suppress an increase in the pressure of the liquid in the main liquid chamber 32. Therefore, an increase in the dynamic spring constant is suppressed, and the engine The dynamic spring constant in the frequency domain of vibration at the time of high rotation is reduced, and high-frequency vibration is reliably absorbed.
[0046]
On the other hand, since the switching valve 82 is connected to and supported by the outer cylinder 16 via the block 64 and a support member 112 that can be elastically deformed, when the switching valve 82 is switched between the open state and the closed state, Even if the plunger 86 in the switching valve 82 abuts against the inner wall surface of the main body 82A of the switching valve 82 and shock vibration is generated, it is absorbed and reduced by the resistance based on the internal friction of the support member 112.
[0047]
Therefore, when the vibration isolator 10 having such a switching valve 82 is fixed in the engine room of an automobile as in the present embodiment, vibrations associated with the contact of the plunger 86 with the inner wall surface of the main body 82A are generated. , It will not be transmitted to the passenger compartment through the car body.
[0048]
In the above embodiment, the support member 112 is vulcanized and bonded to the block 64 fixed to the outer cylinder 16 that is united with the bottom plate 12 by being crimped to the bottom plate 12 as the first mounting member. The support member 112 may be directly vulcanized and bonded to the outer cylinder 16, or may be vulcanized and bonded to the bottom plate 12 or the support base 24.
[0049]
The support member 112 according to the present embodiment is integrally vulcanized and bonded to the block 64 and the connecting plate 114. However, instead of the block 64, the support member 112 is vulcanized and bonded to the outer cylinder 16, and a switching valve 82 is attached thereto. It may be fixed.
[0050]
Furthermore, as a structure for operating the switching valve 82, not only a solenoid configured by the coil 84 and the plunger 86 of the present embodiment, but also a motor, a rotary solenoid, and the like are conceivable. Further, unlike the above embodiment, the first mounting member side may be connected to the engine and the second mounting member side may be connected to the vehicle body.
[0051]
Moreover, although the structure which uses the vibration isolator 10 as an engine mount was shown in the said embodiment, this invention is not limited to this, The vibration isolator 10 is used for the support of a cab mount, a body mount, a general industrial machine, etc. Of course, it may be.
[0052]
【The invention's effect】
As described above, the vibration isolator of the present invention has the effect of reducing the shocking vibration that occurs when the switching valve is opened and closed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a vibration isolator according to a first embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of a switching valve employed in the vibration isolator according to the first embodiment of the present invention, showing a closed state.
FIG. 3 is an enlarged cross-sectional view of a switching valve employed in the vibration isolator according to the first embodiment of the present invention, showing an open state.
[Explanation 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 sub liquid chamber 74 Second air chamber 82 Switching valve 112 Support material (elastic member)

Claims (1)

A first attachment member coupled to one of the vibration generator and the vibration receiver;
A second attachment member coupled to the other of the vibration generating portion and the vibration receiving portion;
An elastic body provided between the first mounting member and the second mounting member and deformed when vibration occurs;
A main liquid chamber in which the elastic body can be expanded and contracted as a part of a partition wall and a liquid is enclosed;
A secondary liquid chamber communicated with the main liquid chamber via a restriction passage;
A deformable diaphragm constituting a part of a partition wall of the sub liquid chamber;
An air chamber disposed opposite to the sub liquid chamber and the diaphragm and filled with gas;
An open state connected to the first mounting member or the second mounting member via an elastic member that can be elastically deformed, and the air chamber communicating with the atmosphere, and a closure that closes the air chamber and the atmosphere A switching valve that can take a state;
An anti-vibration device comprising:

Images