JP3163862B2 - Vibration absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnet-driven vibration absorbing device used for an engine mount for supporting an automobile engine on a vehicle body in a vibration-proof manner.

[0002]

2. Description of the Related Art Conventional vibration absorbers of this type include:
For example, there is one shown in FIG. 10 applied to an engine mount of a vehicle. That is, the working chamber 73 is provided in the elastic body 71 disposed between the upper and lower mounting blocks 77 and 78, and the working chamber 7 is provided on the mounting block 77 side by the orifice 72.
A pressure control chamber 74 communicating with the pressure control chamber 3 is provided, and a bellows 75 is disposed in the pressure control chamber 74. A working fluid is sealed in the working chamber 73 and the pressure regulating chamber 74. One mounting block 77 is connected to, for example, the engine side, and the mounting block 78 is mounted to the vehicle body side. The elastic body 7 in which the working fluid sealed in the working chamber 73 is generated by vibration from the engine
When it is pressurized by the deformation of No. 1, it passes through the orifice 72 and is housed in the pressure regulating chamber 74 without pressure.
Therefore, the fluid pressure in the fluid chamber including the working chamber 73 and the pressure regulating chamber 74 does not constantly change, thereby cutting off the transmission of vibration to the vehicle body.

[0003]

However, in such a conventional vibration absorbing device, when the vibration from the engine has a high frequency, the hydraulic fluid cannot sufficiently move through the orifice. For this reason, for example, there has been a problem that the vibration of the engine of about 80 to 200 Hz, which is a source of the muffled sound inside the vehicle, is transmitted to the vehicle body. Accordingly, an object of the present invention is to provide a vibration absorbing device that can reliably reduce vibrations in a wide range from low frequencies to high frequencies, focusing on such conventional problems.

[0004]

Accordingly, the present invention provides an elastic body interposed between a vibrating body and a support, a working chamber formed in the elastic body and filled with a liquid, A pressure regulating chamber which communicates with the chamber via an orifice and has a diaphragm, a movable plate of a magnetic material which constitutes one wall surface of the working chamber and whose outer periphery is elastically supported by a first elastic member; And an electromagnet installed facing the air gap, and a second electromagnet installed in the air gap between the movable plate and the electromagnet.
And second elastic members, and a control device for controlling the current supplied to the electromagnet possess, the second elastic member is supplied to the electromagnet
When the maximum current is flowing, the load line of the first elastic member and the electromagnet
Between the movable plate and the electromagnet from the point where the
Is set so that the spring force acts on it.

[0005]

A working chamber formed in an elastic body and filled with a liquid and a pressure regulating chamber having a diaphragm communicate with each other through an orifice, so that a large damping force is generated at a relatively low frequency such as a so-called engine shake. In the required area, the dynamic spring constant is reduced at a frequency lower than the resonance frequency by setting the resonance frequency of the vibration system using the fluid in the orifice as the mass and the expansion elasticity of the elastic body as the spring as a spring, at a predetermined value. Therefore, the vibration transmitting force is reduced.

[0006] Further, since the electromagnet is provided opposite to a movable plate made of a magnetic material elastically supported by the first elastic member via an air gap and constitutes one wall surface of the working chamber, a high frequency region is provided. In, the displacement of the movable plate is generated by the electromagnet, and the displacement is controlled so as to be in the opposite phase to the input vibration, so that the dynamic spring constant is reduced and the vibration transmitting force is reduced.

Further , since the second elastic member is disposed in the air gap between the movable plate and the electromagnet , the movable plate does not stick to the electromagnet even when an excessive external force or the like acts. And the spring force of the second elastic member is supplied to the electromagnet.
When the maximum current is applied, the load straight line of the first elastic
Since it acts from the point where the stone's suction force characteristic curve touches,
Do not affect the control of the movable plate in the normal control range.
No.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. Ma
FIG. 1 shows a vehicle as a basic embodiment on which the present invention is based.
Both engine mounts are shown. The engine mount unit 1 includes a liquid filling section 2 and an electromagnet section 3. In the liquid enclosing section 2, a working chamber 9 is provided in an elastic body 8 disposed between the upper and lower mounting blocks 5 and 14, and a pressure regulating chamber communicating with the working chamber 9 by an orifice 11 on the mounting block 5 side. 10 are provided. The mounting block 5 has mounting bolts 4 for coupling to the engine side.

The working chamber 9 is surrounded by an elastic body 8 and a movable plate 12, and a working fluid is sealed therein. The elastic body 8 is deformed by a load change caused by vibration of the engine, and thereby the volume of the working chamber 9 changes. The movable plate 12 is formed of a magnetizable magnetic metal material, and its outer periphery is elastically supported by a mounting block 14 via a movable plate support spring 13, and constitutes one wall surface of the working chamber 9. When the movable plate 12 is attracted by the magnetic force of the electromagnet 16 described later, the movable plate 12 moves in the direction of the electromagnet 16 to increase the volume of the working chamber 9. A diaphragm 15 is disposed in the pressure regulating chamber 10, and its volume changes in accordance with a change in the working fluid in the working chamber 9 flowing through the orifice 11 and flowing out to the working chamber 9. The internal pressure of the pressure regulating chamber 10 is maintained at a constant pressure, for example, the atmospheric pressure.

The electromagnet section 3 is housed in an electromagnet case 7 in which an electromagnet 16 composed of a yoke 17 and a coil 18 is fixed to a mounting block 14. The movable plate 12 described above is arranged at a position facing the electromagnet section 3 with an air gap 19 at a predetermined interval. The electromagnet case 7 has a mounting bolt 6 for the vehicle body.

FIG. 2 shows the relationship between the attractive force of the electromagnet 16 and the air gap 19 using the current flowing through the electromagnet 16 as a parameter. As shown in this figure, the attractive force characteristic of the electromagnet 16 decreases as the air gap 19 increases, in inverse proportion to the square of the air gap. When the load straight line of the movable plate support spring 13 is superimposed on this attractive force-air gap characteristic curve, the intersection of the attractive force characteristic of the electromagnet 16 and the load straight line of the movable plate support spring 13 is obtained as an equilibrium point. When the movable plate 12 is attracted to the electromagnet 16 side, it comes to its equilibrium point position. Accordingly, this allows the displacement of the movable plate 12 to be controlled according to the current. In this embodiment, active damping is performed using this property.

Referring to FIG. 2, the relationship between the attraction force characteristic of the electromagnet 16 and the elastic characteristic of the movable plate supporting spring 13 will be described. Now, when the current of the electromagnet 16 is increased, the attractive force characteristic curve of the electromagnet 16 moves in the U direction in the figure, and the intersection of the movable plate support spring 13 with the load straight line moves sequentially as A to C. . These intersections are points where the attraction force of the electromagnet and the load force of the movable plate support spring are balanced, and it can be seen that the displacement position of the movable plate changes to A, B, and C due to an increase in current.

When the current is further increased, the attractive force characteristic of the electromagnet 16 and the load straight line of the movable plate supporting spring 13 come into contact at point D, and the current at this time can be controlled by the maximum current IMAX.
Becomes That is, when the current value is further increased and, for example, IOVER is passed, the intersection between the attractive force characteristic of the electromagnet 16 and the load straight line of the movable plate support spring 13 disappears, and the electromagnet 1
Since the suction force of 6 exceeds, the movable plate 12 is attracted to the upper surface of the yoke 17 and cannot be controlled.

Here, the maximum displacement SMAX of the movable plate up to the limit of control and the maximum current IMAX of the electromagnet are obtained . Attraction force F1 of the electromagnet 16 is inversely proportional to the square of the air gap x, is proportional to the square of the current I, F1 = (α · I 2) / (x + β) represented by ² · (1). Here, α and β are constants determined by the shape of the electromagnet.

On the other hand, the load F2 by the movable plate supporting spring 13
Is as follows: F2 = k (Lx) (2) Here, k: the spring constant of the movable plate supporting spring 13 L: the initial position of the movable plate 12 Therefore, at these intersections, the following equation holds. (Α · I ² ) / (x + β) ² = k (L−x) (3)

The maximum displaceable displacement of the movable plate 12 is SMAX = L-xMAX (4). Meanwhile, xmax is given as a differential value becomes 0 x when differentiating the I ² in the formula (3).
That is, by transforming equation (3), I ² = − (k / α) {x ³ + (2β−L) x ² + (β ² −2βL) x−β ² L} (5) In order for the differential value to be 0, the following equation should be satisfied. 3x ² +2 (2β−L) x + (β ² −2βL) = 0 (6)

By solving the above equation, xMAX = (2L-β) / 3, -β (7) is obtained. By substituting this into Expression (4), the maximum displacement of the movable plate 12 is given by SMAX = (L + β) / 3 (8) From the above equations (5), (7) and (8), to obtain the maximum displacement SMAX, the current IMAX shown in the following equation is required. IMAX = 2 (k / α) ^1/2 SMAX ³ (9)

In this embodiment, as the electromagnet 16, the attractive force characteristic curve of the electromagnet 16 and the characteristic straight line of the movable plate supporting spring 13 as a load when the current is changed based on each value obtained above. Is the distance (maximum displacement) SMAX between the position XMAX of the point D where the contact is made and the initial position L of the movable support spring 13.
A stroke that is larger than the stroke S required for control and that can obtain the stroke S within an allowable current value is used.

Next, control of the engine mount unit 1 having the above configuration will be described. When the vibration of the engine is applied to the engine mount unit 1, the mounting block 5
Makes relative movement with the mounting block 14 via the elastic body 8. At this time, when the vibration is relatively low frequency such as an engine shake, the working fluid in the working chamber 9 compressed by the elastic body 8 passes through the orifice 11 and is stored in the pressure regulating chamber 10 without pressure. The hydraulic pressure of the hydraulic fluid in the chamber 9 does not constantly change, and exhibits relatively good vibration absorption performance.

However, when the frequency of the vibration becomes high, the combination of the elastic body and the orifice is not sufficient.
Since the hydraulic fluid does not move sufficiently through the engine, the hydraulic pressure fluctuates inside the working chamber 9, and vibration from the engine is transmitted to the vehicle body. Therefore, in the present embodiment, the movable plate 12 moves in the opposite phase to the vibration according to the signal of the vibration detector such as the acceleration sensor.
Driving the electromagnet 16 actively controls the working fluid pressure in the working chamber 9 to be constant, thereby preventing engine vibration from being transmitted to the vehicle body. Since the movable plate 12 has a larger spread than the equivalent piston area of the elastic body 8, the movable plate 12 can compensate for the hydraulic pressure with a relatively small amplitude movement. In addition, the movable plate 12 is moved to the electromagnet
Is applied with a DC bias current.

FIG. 3 shows a block diagram of a control device for controlling the current of the electromagnet 16. The control device 20 includes a crank angle sensor 21 for detecting the crank angle of the engine, an acceleration sensor 22 for detecting the acceleration of the vehicle body, an A / D converter 23 for A / D converting an analog signal of the acceleration sensor 22, and a crank angle sensor 21. And the signal of the acceleration sensor 22,
The CPU 24 that determines the control force of the electromagnet 16 and commands the electromagnet drive current, and sets the electromagnet current command value from the CPU 24 to D
/ A converter D / A converter 25 and current control unit 2
6.

The control unit inputs a signal from the acceleration sensor 22 installed on the vehicle body and a signal from the crank angle sensor 21 of the engine to the CPU 24.
At 24, the drive current value of the electromagnet 16 is determined. CPU2
The drive signal from the electromagnet 4 is converted into an analog signal by the D / A converter 25 and then sent to the current control unit 26, and the electromagnet 16 is driven by the drive current controlled by the current control unit 26 as instructed by the CPU 24. Driven.

That is, the engine mount unit 1
Since it functions as a normal fluid mount for the engine shake, high damping and high rigidity characteristics can be obtained by resonance of a vibration system having a working liquid in the orifice 11 as a mass and an elastic body 8 as a spring, thereby reducing engine vibration. I can do it.

Next, active control is performed for idle vibrations and muffled sounds having higher frequencies. When a control current is applied to the electromagnet 16, a magnetic force is generated as described above, and the movable plate 12 is displaced by the control force of the magnetic force. This control force is applied in the direction of reducing the vibration in the axial direction of the engine mount as a pressure fluctuation with respect to the working chamber 9 and the pressure regulating chamber 10.

For example, in the case of a four-cylinder engine vehicle, the main cause of idle vibration and muffled noise is that engine vibration of a secondary component of engine rotation is transmitted to the vehicle body via an engine mount. Therefore, here, by outputting the control output signal based on the engine rotation secondary frequency, idle vibration and muffled noise are reduced.
Here, when the drive current value is determined by the CPU 24, an output control signal is generated using an adaptive control law. In particular, in the case of the engine mount, the sampling time is further changed between when the engine is running at a low speed and when the engine is running at a high speed.

Here, the control output signal W is held and output as a time history vector quantity. The output timing is triggered by the crank angle 180 ° signal from the crank angle sensor 21 and is output for one cycle until the next trigger is applied. First, an evaluation signal (error signal) output E from the acceleration sensor 22 when an impulse input is given to the control output signal is measured in advance. This signal is also stored as a vector quantity C. next,
The sum of the response waveforms when this vector amount C is issued at the break of the timing signal is calculated as the reference signal RT. These are represented as follows: W = [W [0], W [1],..., W [TAP-1]] (10) RT = [R (N), R (N-1),. -TAP + 1)] (11) where TAP is the number of taps in one cycle.

In order to stabilize the control system, the above W
Is updated by the following equation. W (N + 1) = W (N) −γ · RT · E (N) (12) where γ is a convergence coefficient and E is an error signal. As the convergence coefficient γ increases, the convergence becomes faster, but divergence may occur. Conversely, if the control system and the vibration conditions are determined, the optimum value of the convergence coefficient is determined.

The specific rewriting (updating) calculation of the control output signal W is performed according to the flow shown in FIG. First, in step 100, an initial value of a control signal is set. This is for applying a predetermined current to the electromagnet 16 in advance to attract the movable plate 12 to the reference position. In step 101, the filter coefficient of the transfer function filter C # is appropriately added to calculate the reference signal RT used until the next trigger is applied. Then, in step 102, the counter i is cleared to zero.

Then, in step 103, the i-th filter coefficient Wi of the adaptive digital filter W is output as the control signal y. In the next step 104, after reading the error signal E, the counter j is cleared to zero in step 105, and then in step 106, the j-th filter coefficient Wj of the adaptive digital filter W is calculated by the above equation (12). It is updated according to. When the updating process in step 106 is completed, the process proceeds to step 107 to check whether a trigger has been activated. If the trigger has not been applied, the process proceeds to step 108 in order to update the next filter coefficient of the adaptive digital filter W or output the control signal y.

In step 108, it is checked whether or not the counter j has reached the output number TAP (more precisely, since the counter j starts from 0, the value obtained by subtracting 1 from the output number TAP). Here, step 103
After outputting the filter coefficient Wi of the adaptive digital filter W as the control signal y, it is determined whether or not all the filter coefficients of the adaptive digital filter W have been updated. Therefore, when all the filter coefficients have not been updated, after the counter j is incremented in step 109,
Returning to step 106, the above-described processing is repeated.

However, if all the updates have been completed in the check in step 108, the process proceeds to step 110, where the counter i is incremented, and after waiting for a predetermined sampling period to elapse, the process proceeds to step 103.
And the above-described processing is repeated. On the other hand, when the reference signal is input and the trigger is activated in step 107, the process proceeds to step 111, and the counter i (exactly, since the counter i starts from 0, the counter i
Is stored as the latest output count TAP, and then the flow proceeds to the next flow.

According to the above processing, the control signal is supplied from the control device to the engine mount at a predetermined sampling cycle from the time when the trigger is activated. Since the electromagnet is preloaded with an initial value in advance, if a control signal y larger than a predetermined value is supplied, the movable plate 12 is displaced downward from the reference position toward the electromagnet, and a control signal smaller than the predetermined value is generated. When y is supplied, the movable plate 12 is displaced upward from the reference position.

When the movable plate 12 is displaced in this way, the volume of the working chamber 9 changes, and the working fluid pressure in the working chamber is actively controlled to generate a control force. Since the control force in the vertical direction is generated, if the phase of the control force is opposite to the phase of the vibration input from the engine 30, the input vibration is canceled out here, and The vibration transmissibility is reduced.

The control signal y is the filter coefficient Wi of the adaptive digital filter W. Each filter coefficient Wi of the adaptive digital filter W is
109, the synchronous Filtered-X
The control signal y is supplied to the engine mount after each filter coefficient Wi of the adaptive digital filter W converges to an optimum value after a predetermined time has elapsed since the above equation (12) is sequentially updated according to the LMS algorithm. As a result, vibrations input from the engine to the engine mount are canceled out here, and idle vibration and muffled sound vibration transmitted from the engine to the members via the engine mount are reduced.

In the sampling described above, since the number of W filters is large, the calculation load in a low rotation range is large. Therefore, there is a demand that the sampling time be as short as possible in consideration of the amount of calculation time at this time. is there. However, if the control is performed while keeping it short, the sampling time becomes relatively coarse in the high rotation range, the continuity of the control signal is lost, and high-precision control cannot be performed. Therefore, in this embodiment, the program is switched between the low rotation range and the high rotation range, and the sampling is shortened in the high rotation range,
The control accuracy is kept high over a wide range.

As described above, in the present embodiment, the liquid filling section in which the working fluid is filled in the pressure regulating chamber 10 communicating with the working chamber 9 provided in the elastic body 8 and the orifice 11 is provided.
Since the movable plate 12, which is provided with an electromagnet portion and is supported by the movable support spring 13 and constitutes one wall surface of the working chamber, can be displaced and driven by the electromagnet 16 so as to move in a phase opposite to the vibration, the idle vibration and the muffled sound are generated. In contrast, pressure fluctuation due to the displacement of the movable plate is added in the direction of reducing vibration in the axial direction of the engine mount, and active control for actively suppressing vibration is performed. Moreover, at this time, the maximum stroke of the movable plate 12 is set to a range smaller than the distance SMAX between the position XMAX of the point D where the characteristic curve of the attraction force of the electromagnet and the characteristic straight line of the movable plate support spring and the initial position L of the movable support spring. The movable plate is not attracted to the electromagnet because the electromagnet 16 is controlled so as to perform the operation.

Next, an embodiment of the present invention is shown in FIG. This embodiment is different from the above-described basic embodiment in that an elastic member is provided at the tip of an electromagnet. Even in this embodiment,
The engine mount unit 31 includes a liquid sealing portion 32 and an electromagnet portion 33. A mounting bolt 35 for the engine is provided on a mounting block 35 at one end, and an electromagnet case of the electromagnet portion is provided on a mounting block 52 at the other end. 37 is provided with a bolt 36 for attachment to the vehicle body.

The electromagnet section 33 includes a yoke 47 and a coil 48.
An electromagnet 46 is accommodated in an electromagnet case 37 fixed to the mounting block 44 of the engine mount unit 31. A movable plate 42 to be described later is arranged at a position facing the electromagnet 46 with an air gap 49 at a predetermined interval. The air gap 49 at the end of the electromagnet 46
An elastic member 50 is arranged inside. A hollow elastic body 38 is provided in the liquid sealing portion 32 between the mounting block 35 and the outer shell 44 of the mounting block 52, and the working chamber 3 is provided in the elastic body 38.
9 are formed. The mounting block 35 is provided with a pressure regulating chamber 40 communicating with the working chamber 39 through the orifice 41. The action chamber 39 includes an elastic body 38 and a movable plate 42.
And is surrounded by

The elastic body 38 is deformed by a load change caused by the vibration of the engine, and changes the volume of the working chamber 39. The movable plate 42 is made of a magnetizable elastic metal material, and its outer periphery is supported by the mounting block 44 and the elastic body 38 via the movable plate support spring 43 to form one wall surface of the working chamber 39. ing. When the movable plate 42 is attracted by the magnetic force of the electromagnet 46, it moves in the direction of the electromagnet 46 to increase the volume of the working chamber 39. Pressure regulation chamber 40
The volume of the working fluid changes in response to the flow of the working fluid from the working chamber 39 or the working fluid flowing out of the working chamber 39, and the internal pressure is maintained at a constant pressure, for example, the atmospheric pressure. ing.

[0040] Also in this embodiment, the similar to the basic embodiment, is basically up to the limit point D of the previous Figure 2, is controlled. By the way, considering the usage environment of the engine mount, due to excessive input from the road surface other than engine vibration,
There is a case where an external force acts to push the movable plate 42 toward the electromagnet 46 side. At this time, the movable plate 42 may stick to the electromagnet 46 and become uncontrollable. That is, as shown in FIG. 6, there is another point A2 other than the point A1 between the attraction force characteristic of the electromagnet 46 and the load straight line of the movable plate supporting spring 43. Since the point A2 is an unstable point, when a force that enters the area to the left of the point A2 in FIG. 6 is applied, the movable plate 42 is attracted to the upper surface of the electromagnet 46 and becomes uncontrollable. Note that, as the current I increases, the points A1 and A2 become closer to each other, and it becomes easy to lose control due to a small external force.

As shown in FIG. 6A, even if the maximum current is slightly larger than IMAX of the above equation (9), the attractive force characteristic of the electromagnet 46 and the load straight line of the movable plate supporting spring 43 are not changed. Has no intersection. That is, since the attractive force of the electromagnet 46 exceeds the load of the movable plate support spring 43, the movable plate 42 is attracted to the upper surface of the electromagnet 46. In this embodiment, an elastic member 50 is newly provided at the tip of the electromagnet 46 in order to avoid these problems.

FIG. 7 shows the attraction force characteristic of the electromagnet 46 and the load straight line of the movable plate supporting spring 43 according to this embodiment. 7, the F straight line is the load straight line of the movable plate support spring 43, and the G straight line is the load straight line of the newly provided elastic member 50 and the parallel spring of the movable plate support spring 43. That is,
Up to the control limit point D, as the current I of the electromagnet 46 is increased, the load straight line of the movable plate support spring 43 and the electromagnet 46
Has a point of intersection (points A to D), and the displacement of the movable plate 42 is controlled according to the current.

Next, the elastic member 50 is disposed so that the movable plate 42 acts from the position XMAX at which the movable plate 42 is displaced by the maximum SMAX on the F straight line. 50 and movable plate support spring 4
The spring constant K2 of the elastic member 50 is set so that the combined spring force of the elastic member 50 and the elastic member 50 exceeds the attractive force of the electromagnet 46 at the time of the maximum current IMAX. Therefore, the air gap 4 is larger than the point D.
9 in an area where the length of the electromagnet 46 is small (an area where the applied load is large) and an unstable intersection A between the elastic member 50 and the load straight line G of the composite spring of the movable plate support spring 43.
2 does not occur.

As a result, an excessively large external force is applied transiently,
Even if the movable plate 42 is closer to the electromagnet side than the control limit point D, the movable plate 42 is completely absorbed and does not fall out of control. If there is no external force, the load and the attractive force of the electromagnet are balanced. It returns to the area on the right and equilibrates at a stable point. In addition, even if an excessive external force is continuously input, the elastic member 50 functions as a cushioning material.
Does not collide, and does not generate a clicking sound.

Further, when the current is equal to or greater than the maximum value IMAX of the control, if the elastic member 50 is not provided, as described above,
As shown in FIG. 6A, the attractive force of the electromagnet 46 and the load straight line of the movable plate support spring 43 do not have an intersection, so that the movable plate 42 is attracted to the electromagnet 46.
Is provided, a stable intersection is provided to the left of the point D, and the control does not occur. Further, even when the spring constant of the movable plate supporting spring 43 is reduced due to the deterioration with time, the electromagnet 4 is not required in the entire region without the elastic member 50.
6 exceeds the load straight line of the movable plate support spring 43,
Although the movable plate 42 is attracted to the yoke 46, if the elastic member 50 is provided, the stable intersection point is located to the left of the point D, so that the control is not lost.

Next, the condition of the spring constant of the elastic member 50 is determined. That is, in FIG. 7, the combined spring of the elastic member 50 and the support spring 43 of the movable plate sets the current of the electromagnet 46 to I
The spring constant of the load straight line G passing through the point E at which the air gap 49 becomes the suction force at the time of MAX and the limit D of the control when only the movable plate supporting spring 43 is used should be larger than the spring constant. First, the current IMAX,
The absorption force when the air gap 49 is zero is obtained. If X = 0 in the above equation (1) representing the attraction force of the electromagnet, the equation (1)
3). F1 = (α · I ² ) / (X + β) ² (1) F1 = (α · I ² ) / β ² (13)

The attraction force at the control limit D point on the F straight line of only the movable plate supporting spring 43 is obtained by substituting XMAX = (2L-β) / 3I = IMAX into the equation (1), and F1 = (9α · IMAX) ² ) / {4 (α + β) ² } (14) Therefore, the spring constant K of the composite spring is as follows: K = {α · I ² / β ² −9α · IMAX ² / {4 (α + β) ² } / {(2L−β) / 3} (15) Becomes

The spring constant K2 of the elastic member 50 may be at least a value obtained by subtracting the spring constant K1 of the movable plate supporting spring 43 from the spring constant K of the composite spring. That is, K2 ≧ {α ｛I ² / β ² -9α ・ IMAX ² / {4 (α + β) ² } / ｛(2L-β) / 3｝ -K 1 (16)

In this embodiment, even if an excessive external force is applied or an input larger than the control maximum current is applied, the movable plate is not attracted to the electromagnet and becomes uncontrollable. This has the effect that no collision sound is generated between the plate and the electromagnet yoke.

FIG. 8 shows a second embodiment in which the electromagnet portion used in the above embodiment is further improved. That is, in each of the electromagnet sections, the coil of the electromagnet 60 is divided into a coil 61 and a coil 62 and connected to the power supply 63 in parallel. In addition, 64 is a movable plate.
As a result, the inductance of the coils 61 and 62 as viewed from the power supply 63 is reduced as compared with the case of a single coil, so that the effect of improving responsiveness in a high frequency range is obtained.

In addition, when an alternating current is applied as an electromagnet, one having a function of adjusting positive and negative gains can be used to eliminate the bias of displacement. That is, as shown in FIG. 9A, the attractive force acting on the movable plate from the electromagnet increases as the gap (air gap) decreases, even if the current I is changed to the same positive and negative amount. Because the displacement of the movable plate is different, the bias of the displacement is corrected as shown in FIG. 3B by appropriately adjusting the positive and negative peak values of the current by ΔI. Thereby, the vibration absorbing function in each embodiment can be performed more advantageously.

In each of the above embodiments, a DC bias current is applied to the electromagnet so that the movable plate is in the neutral position in advance when the movable plate is not controlled. However, the same effect can be obtained by using a permanent magnet instead of the DC bias current. Obtainable. Also,
The elastic member 50 of the present embodiment is not limited to rubber, but may be, for example, a metal spring. Furthermore, although the embodiment has been described as applied to an engine mount of a vehicle, there is no limitation on the application target, and the vibration transmission frequency can be used in a wide range to obtain a reliable vibration transmission effect.

[0053]

As described above, the present invention comprises a working chamber formed in an elastic body and a pressure regulating chamber having a diaphragm connected to the working chamber through an orifice. In the device, an electromagnet is opposed to a movable plate of a magnetic material elastically supported by a first elastic member via an air gap, which constitutes one wall surface of a working chamber, so that a relatively low frequency region such as an engine shake is provided. Then, the vibration transmission is attenuated in a vibration system in which the liquid in the orifice is the mass and the expansion elasticity of the elastic body is a spring, and in a high frequency region, the movable plate is displaced by an electromagnet, which is converted into input vibration. On the other hand, by controlling the phases to be opposite to each other, the vibration transmission is attenuated, and there is an effect that the vibration is reliably reduced over a wide range.

[0054] Then, as so further are disposed a second elastic member to the air gap between the movable plate and the electromagnet, or acts excessive external force, control the maximum current or a current is inputted to the electromagnet Even in such a case, there is an effect that the movable plate is not stuck to the electromagnet and the vibration is stably reduced. At this time, the second elastic member is supplied to the electromagnet.
When the maximum current is applied, the load straight line of the first elastic
The spring force acts from the point where the stone's suction force characteristic curve touches.
Is set so that in the normal control range
It does not affect the control of the movable plate.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a basic embodiment serving as a base of the present invention.

FIG. 2 is a diagram illustrating a relationship between an attractive force characteristic of an electromagnet and a load characteristic of a movable plate supporting spring.

FIG. 3 is a block diagram of a control device that controls a current of an electromagnet.

FIG. 4 is a flowchart showing a flow for obtaining a control output to an electromagnet.

FIG. 5 is a sectional view showing the first embodiment of the present invention.

FIG. 6 is a diagram illustrating the relationship between the attraction force characteristics of the electromagnet and the load characteristics of the movable plate support spring.

FIG. 7 is a diagram illustrating the relationship between the attraction force characteristics of the electromagnet and the load characteristics of the movable plate support spring and the elastic member.

FIG. 8 is a diagram showing a second embodiment.

FIG. 9 is a diagram showing an example of gain adjustment of an electromagnet.

FIG. 10 is a sectional view showing a conventional example.

[Explanation of symbols]

 1, 31 Engine mount unit 2, 32 Liquid sealing part 3, 33 Electromagnet part 5, 14 Mounting block 7, 37 Electromagnet case 8, 38 Elastic body 9, 39 Working chamber 10, 40 Pressure regulating chamber 11, 41 Orifice 12, 42 Movable plate 13, 43 Movable plate support spring (first elastic member) 15 Diaphragm 16, 46 Electromagnet 17, 47 Yoke 18, 48 Coil 19, 49 Air gap 20 Controller 35, 52 Mounting block 44 Outer shell 50 Elastic member ( (Second elastic member) 60 electromagnet 61, 62 coil 63 power supply 64 movable plate

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-24338 (JP, A) JP-A-4-362331 (JP, A) JP-A-5-164181 (JP, A) JP-A-61-1 207213 (JP, A) JP-A-5-60168 (JP, A) JP-A-55-107080 (JP, A) JP-A-58-157363 (JP, A) JP-A-60-118044 (JP, U) Japanese Utility Model Application Hei 6-30544 (JP, U) Japanese Utility Model Application Hei 7-4944 (JP, U) Japanese Patent Publication No. 39-21406 (JP, B1) Japanese Patent Publication No. 43-7498 (JP, B1) German Patent Application Publication No. 41141637 (DE, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16F 13/26 B60K 5/12 H02K 33/04 B06B 1/04

Claims (2)

(57) [Claims] 1. An elastic body interposed between a vibrating body and a support, a working chamber formed in the elastic body and filled with a liquid, and communicated with the working chamber via an orifice. A pressure regulating chamber provided with a diaphragm, a movable plate of a magnetic material which constitutes one wall surface of the working chamber and whose outer periphery is elastically supported by a first elastic member, and which faces the movable plate via an air gap. An installed electromagnet, and a second electromagnet disposed in an air gap between the movable plate and the electromagnet.
Yes of an elastic member, and a control device for controlling the current supplied to the electromagnet
And said second elastic member, the current supplied to the electromagnet
At the maximum, the load straight line of the first elastic member and the electromagnet
The movable plate and the electromagnetic force
A vibration absorber , wherein the spring force is set between the stones. 2. The second elastic member has a load force of:
When the air gap is zero, the suction of the electromagnet is
The feature is that it is set to be larger than the gravitational force
The vibration absorbing device according to claim 1, wherein