JPH11272340A - Active type vibration isolator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration isolator capable of suppressing the generation of noise in the case of driving an electromagnet by a pulse signal. SOLUTION: When a switching device 13 is turned on/off by an amplitude- modulated signal corresponding to a change in vibration in the idling, a control electric signal corresponding to the amplitude and phase of vibration of a power unit is supplied from a battery power supply 14 to an electromagnet 55 mounted on an engine and an excitation board is vertically excited. Although noise is generated due to a sudden current change at the ON/OFF of a current from the power supply 14 to the electromagnet 55, the noise can be shielded by a coaxial shielding wire 15 to be a feeder directly connected to the electromagnet 55 by using a core 15a of the wire 15 as a connection line from the battery power supply 14 and using a shielding wire 15b as a connection line to be connected to the collector terminal of the switching device 13. Consequently the occurrence of adverse effects to the operation of a computer or the like loaded on an automobile can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active vibration isolator for reducing active vibration from a member to be damped such as a vehicle.

[0002]

2. Description of the Related Art Conventionally, as an active vibration isolator of this type, a part of a wall portion is constituted by a main rubber elastic body which is elastically deformed by a vibration input from a member to be damped, and a liquid is sealed therein. A vibration isolator main body having a liquid chamber and another part of a wall of the liquid chamber being constituted by a vibrating plate displaced by a driving unit; and a control electric device corresponding to vibration of a member to be damped. A signal is added to the driving means, and a vibration control means for controlling the vibration plate to vibrate by the driving means,
There is known an apparatus in which the excitation of a vibration plate is controlled to control the internal pressure of a liquid chamber to generate a vibration force, thereby reducing the vibration of a member to be damped.

For example, a sine wave signal having a frequency, an amplitude and a phase corresponding to the vibration input of a member to be damped is used as a control electric signal, which is supplied to a driving means to generate an exciting force. However, in order to obtain a sine wave drive signal corresponding to the vibration waveform of the vibration suppression target member, it is necessary to use an adaptive control device or the like, and it is necessary to amplify the obtained sine wave signal with a power amplifier. There is a problem that the control cost becomes expensive.

[0004]

On the other hand, in a vehicle, active control is most required when the engine is running at a low speed such as idling, and the vibration frequency is 15 to 15.
In consideration of the case where active control is performed in such a limited frequency range as low as 20 Hz, inexpensive active control using a pulse signal as a control electric signal has been considered. For example, by generating a pulse signal having a converted amplitude or width corresponding to the vibration input of the vibration suppression target member, and turning on / off the switching means by the pulse signal, it is intended to control the power supply from the power supply to the driving means. Is what you do.

However, when the switching means is turned on and off by a pulse signal, a sudden change in current is caused when power is supplied to and cut off from the driving means. There is a problem that the operation of the device or the like is adversely affected. An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to provide an active vibration isolator that can suppress generation of noise when a driving unit is driven by a pulse signal.

[0006]

Means for Solving the Problems and Effects of the Invention In order to achieve the above object, a structural feature of the invention according to the first aspect is that a main body rubber elastically deformed by a vibration input from a member to be damped. A liquid chamber in which a part of a wall portion is formed of an elastic body and a liquid is sealed therein, and another part of the wall portion of the liquid chamber is formed of a vibration plate displaced by a driving means. A vibration device main body, and a vibration control unit that controls the vibration plate to be vibrated by the driving unit in addition to the driving unit with a control electric signal corresponding to the vibration of the vibration suppression target member, A control pulse generating means for generating a control pulse signal having a characteristic corresponding to the vibration input from the vibration suppression target member; and a control pulse signal having a characteristic corresponding to the input of the control pulse signal. Control power according to An active vibration isolator comprising switching means for applying a signal and supplying power from a power supply, wherein a coaxial shield line is used as a power supply line directly connected to the driving means and provided between the power supply and the ground. I was there.

In the invention according to claim 1 configured as described above, the switching means is turned on / off by a control pulse signal output from the control pulse generation means and having a characteristic corresponding to a vibration input from the member to be damped. As a result, power is supplied to the driving means from a power supply according to the characteristics of the control pulse signal. At this time, noise accompanied by a sudden current change occurs when the drive means is energized / cut off. However, the use of a coaxial shielded wire as a power supply line directly connected to the drive means reduces such noise. It can be shielded by a coaxial shield wire. As a result, according to the first aspect of the present invention, when inexpensive active control of an active vibration isolator is performed using a pulse signal as a control signal, the active vibration isolator is mounted on a vehicle provided with the active vibration isolator. It is possible to prevent adverse effects of noise on operations of a computer, an audio device, and the like.

According to a second aspect of the present invention, in the active vibration isolator according to the first aspect, a center core wire of the coaxial shielded wires is connected to a side closer to a power supply, The reason is that the outer shield wire is connected to the side closer to the ground. In the invention according to claim 2 configured as described above, the high potential side of the coaxial shield wire is a core wire, and the ground side is a shield wire surrounding the core wire, so that noise generation can be effectively shielded. .

Further, the structural feature of the invention according to claim 3 is that, in the active vibration isolator according to claim 1, a two-core shielded wire is used as a coaxial shielded wire, and connection of the driving means is performed. The object is to use two core wires and connect the outer shield wire to the ground. In the invention according to claim 3 configured as described above, the connection of the driving means is 2
By using this core wire and connecting the outer shield wire to the ground, it is possible to more effectively shield the generation of noise due to a sudden current change when the power supply to the drive unit is turned on / off.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an active vibration isolator for removing active vibration of a gasoline engine vehicle according to a first embodiment. Is schematically shown by a block diagram,
FIG. 2 is a sectional view showing an engine mount as a vibration isolator main body constituting the active vibration isolator.

The active vibration isolator includes a phase adjusting pulse generator 11, an amplitude modulator 12, a switching device 13
Are sequentially connected, and the output side of the switching device is connected to a coil of an electromagnet 55 described later of the engine mount 20 to which power is supplied from the battery power supply 14 of the vehicle. However, the power source is not limited to a battery.

The phase adjustment pulse generator 11 includes a CPU,
The microcomputer is configured by a microcomputer including a ROM, a RAM, an I / O, etc., and outputs a phase adjustment pulse signal whose phase has been adjusted based on the input reference signal and reference signal. Here, the reference signal SF is a signal related to a vibration frequency to be damped, for example, an ignition pulse or a crank angle pulse of an engine. As the reference signal SS, a running state signal of the vehicle, such as a shift position signal or a vehicle speed signal, which affects the vibration that changes in the driving state of the vehicle, is used.
Then, in the phase adjustment pulse generator 11, based on the correspondence between the predetermined running state and the phase, the reference signal S
The phase is determined according to S, and the reference signal S
The phase of F is adjusted and output as a phase adjustment pulse signal SI. Here, 2 which occurs when the car is idling
A low-frequency vibration around 0 Hz is a control target, and phase adjustment is performed on a signal in that frequency range.

The amplitude modulator 12 includes a CPU, a ROM, an R
It comprises a microcomputer including an AM and the like, an A / D converter and a D / A converter, and outputs an input phase adjustment pulse signal SI as an amplitude-modulated amplitude-modulated pulse signal SA. That is,
The phase adjustment pulse signal SI is digitally converted by an A / D converter, the amplitude change of the vibration at the time of idling is obtained in advance by data or the like, and the amplitude is digitally modulated based on a map or the like stored in a ROM, and the result of the amplitude modulation is obtained. D / A
The signal is output as an amplitude-modulated pulse signal SA by analog conversion by a converter.

The switching device 13 is constituted by using a bipolar transistor whose emitter is grounded in the ground. The switching device 13 is turned on / off by the input of the amplitude modulation pulse signal SA, and is connected from the battery power supply 14 to the coil of the electromagnet 55 of the engine mount 20. The power supply is controlled. The switching device 13 is not limited to a bipolar transistor, but may be a device having a similar function such as an FET.

As shown in FIG. 1, the power supply line connected to the coil of the electromagnet 55 is a coaxial shield line 15.
Is used. The coaxial shield wire 15 is a core wire 15a.
Are surrounded by a shield wire 15b.
a is used as a connection line from the battery power supply 14 side,
The shield line 15 b is used as a connection line on the collector terminal side of the switching device 13. In other words, noise can be shielded by surrounding the core wire 15a with the shield wire 15b by using the core wire 15a on the high potential side and the shield wire 15b on the ground side.

As shown in FIG. 2, the engine mount 20 has a first support metal member 21 and a second support metal member 30 which are arranged coaxially at a predetermined distance from each other and vertically above and below, and a substantially conical cylinder connecting the two. And a rubber elastic body 41 in a shape of a circle. The first support fitting 21 includes a power unit 61.
, And the second support fitting 30 is fixed to the body 62, whereby the engine mount 20 supports the power unit 61 with respect to the body 62 in a vibration-proof manner.

The first support member 21 has an upper metal member 22 and a lower metal member 23, each of which has a substantially cylindrical shape with a bottom, superposed in the axial direction on each opening side and connected by bolts, and has a hollow portion therein. . A mounting hole 24 is provided at the center of the upper surface of the upper fitting 22, and a screw (not shown) is screwed into the mounting hole 24 so that the first support fitting 21 is attached to the power unit 6.
1 can be attached. First support fitting 2
A hollow rubber elastic film 25 having a substantially hemispherical plate shape is accommodated in the hollow portion 1, and the outer peripheral edge of the rubber elastic film 25 is sandwiched between the upper and lower metal fittings 22 and 23 so that the hollow portion of the first support metal fitting 21 is formed. ,
The upper metal part 22 and the lower metal part 23 are liquid-tightly partitioned with the rubber elastic film 25 interposed therebetween. As a result, an air chamber 26 is formed between the rubber elastic film 25 and the upper fitting 22 so as to communicate with the external space and allows the rubber elastic film 25 to be deformed. A liquid chamber 27 in which an incompressible liquid is sealed and whose volume changes based on the deformation of the rubber elastic film 25 is formed between them. As the liquid sealed in the liquid chamber 27, water, alkylene glycol, polyalkylene glycol, silicon oil, or the like is used. A flow hole 28 is provided in the bottom wall of the lower metal fitting 23.

The second support fitting 30 includes an annular connecting ring fitting 31, a disc-shaped passage forming fitting 32, a cylindrical connecting fitting 33, and a bottomed cylindrical bottom fitting 34 which are coaxial with each other. And each is fixed by bolts. A bolt hole 34a is provided in the peripheral edge of the lower surface of the bottom fitting 34.
A bolt (not shown) is screwed to 4 a so that the second support fitting 30 is attached to the body 62.

The second support member 30 is opposed to the first support member 21 at a predetermined distance axially below the first support member 21, and is elastically provided by a main rubber elastic body 41 interposed therebetween. Are linked. Body rubber elastic body 41
Is a thick, substantially conical cylindrical shape, and the small-diameter upper end opening is the first
The lower end 23 of the supporting member 21 is vulcanized and bonded to the outer peripheral surface of the lower metal member 23, and the lower end opening having a large diameter is vulcanized and bonded to the connecting ring metal member 31. Thereby, the first support member 21 and the second support member 30 are elastically connected by the main rubber elastic body 41,
Between the opposing surfaces of the first support fitting 21 and the second support fitting 30, a space is formed inside surrounded by the main rubber elastic body 41.

The passage-forming bracket 32 is provided with a ring portion 32 on the outer periphery.
a, and a disk-shaped passage portion 32b protruding axially upward on the inner peripheral side. The passage portion 32b is provided with an orifice passage 32c that extends in the radial direction on the outer peripheral side, and one end of the orifice passage 32c is opened on the upper surface and the other end is opened on the lower surface. As a result, a main liquid chamber 42 whose peripheral wall is formed of the main rubber elastic body 41 is formed between the opposing surfaces of the first support fitting 21 and the passage forming fitting 32, and the passage forming fitting 32 and a rubber elasticity to be described later are formed. Body support plate 35
A sub-liquid chamber 43 in which a pressure change occurs due to the displacement of the vibration plate 36 is formed between the opposing surfaces of the vibration plate 36 and the sub-liquid chamber 43 communicates with the main liquid chamber 42 by the orifice passage 32c. . The incompressible liquid is sealed in the main liquid chamber 42 and the sub liquid chamber 43.

The main liquid chamber 42 is also connected to the liquid chamber 27 provided in the first support fitting 21 through the circulation hole 28. Here, in consideration of the wall spring rigidity of the main liquid chamber 42 and the sub liquid chamber 43, the viscosity of the sealed fluid, and the like, the orifice passage 32c has a resonance frequency of the fluid flowing through the interior of about 20 Hz corresponding to idling vibration. The length and cross-sectional area of each passage are set so that the frequency becomes low, and the vibration transmission force is adjusted so as to obtain an effect of reducing the vibration transmitting force in a frequency range around 20 Hz corresponding to idling vibration.

In the center hole 33a at the upper end of the connection fitting 33, a thick rubber elastic support plate 35 is interposed.
The rubber elastic body support plate 35 closes the center hole 33a in a liquid-tight manner. At the center of the bottom surface of the rubber elastic body support plate 35,
A vibrating plate 36 having a protrusion 6b and a protrusion 36b protruding from the center of one side thereof has its tip substantially flush with the upper surface of the rubber elastic body support plate 35 with the protrusion 36b facing upward. The portion 36a is embedded so as to be exposed from the bottom surface of the rubber elastic body support plate 35. The vibration plate 36 is provided with a screw hole 36c coaxially from the disk portion 36a toward the protruding portion 36b.

A cylindrical yoke member 51 made of a ferromagnetic material such as iron is coaxially mounted on the bottom surface of the bottom fitting 34.
It is fixed to the bottom with bolts. Yoke member 51
Has a shaft hole 52 that penetrates the center, and a concave portion 53 that is recessed in the center direction and extends in the entire circumferential direction on the outer peripheral surface. A support rod 54 is inserted into the shaft hole 52 so as to be vertically movable and protrude from the upper surface of the yoke member 51. A thread groove is formed at the upper end 54a of the support rod 54, and a flange 5 protruding from the outer peripheral surface is formed near the upper end 54a.
4b is formed. Inside the concave portion 53, a cylindrical electromagnet 55 is mounted continuously or discontinuously in the circumferential direction. The lead wire 56 of the electromagnet 55 is led out through a small hole 34 b provided on the bottom surface of the bottom fitting 34.

On the upper part of the yoke member 51, a cylindrical push-up member 57 having a bottom and made of metal is disposed coaxially with the bottom part facing upward. The push-up member 57 has an inner diameter of an inner peripheral surface substantially equal to an outer diameter of an outer peripheral surface of the yoke member 51, is vertically movable with respect to the yoke member 51, and has a mounting hole 57a at the center of the bottom surface. ing. Then, the support rod 54 is screwed into the screw hole 36c of the vibration plate 36 through the mounting hole 57a, so that the lifting member 57 is connected to the flange 5 of the support rod 54.
4b, it is fixed to the vibration plate 36. Accordingly, by energizing the electromagnet 55 through the lead wire 56, an electromagnetic force in the axial direction (up-down direction) is exerted on the push-up member 57 by the action of the magnetic field in the magnetic gap between the electromagnet 55 and the push-up member 57, The electromagnetic force is transmitted to the push-up member 57 as a vertical force, and the push-up member 57 causes the vibration plate 36 to vibrate.

The operation of the first embodiment will be described. When the engine is idling, which generates low-frequency vibrations around 20 Hz, a reference signal SF (here, an ignition pulse signal) and a reference signal SF (here, a vehicle speed signal) ) Is input to the phase adjustment pulse generator 11, this signal is converted into a phase adjustment pulse signal adjusted to a phase corresponding to the vibration and output. Next, the phase adjustment pulse signal is converted and output by the amplitude modulation device 12 into an amplitude modulation signal corresponding to a change in vibration during idling. Further, the amplitude modulation signal is transmitted to the switching device 1
3, the switching unit 13 is turned on and off, so that the battery unit 14
A control electric signal corresponding to the amplitude and phase of the first vibration is supplied to the coil of the electromagnet 55 of the engine mount 20.

In the engine mount 20, when the power supply to the electromagnet 55 is turned on and off, the push-up member 57 is pushed up and down, and accordingly the vibration plate 36 is vibrated up and down. This causes an internal pressure fluctuation of the frequency and the pressure corresponding to the vibration frequency of the vibration plate 36 with respect to the sub liquid chamber 43, and the main liquid chamber 42
The liquid flow through the orifice passage 32c occurs between the two chambers due to the relative internal pressure difference between the main liquid chamber 43 and the sub liquid chamber 43, and the fluctuation in the internal pressure of the sub liquid chamber 43 is transmitted to the main liquid chamber 42. An exciting force according to the internal pressure fluctuation is generated. In this way, the vibration transmitted to the body 62 from the power unit 61 is generated by vibrating the vibration plate 36 at a timing corresponding to the low-frequency vibration to be vibration-proof in the body 62 to generate a vibration force. On the other hand, an anti-vibration effect is actively exhibited.

Here, in the present embodiment, the electromagnet 5
The core wire 15a of the coaxial shield wire 15 is used as a connection wire from the battery power supply 14 side, and the shield wire 15b is used as a connection wire on the collector terminal side of the switching device 13 as a power supply line directly connected to the coil 5. I have. For this reason, it is possible to shield the generation of noise due to a sudden change in current when energizing / interrupting the electromagnet 55 from the battery power supply 14 with the coaxial shield line 15. As a result, it is possible to prevent the noise from affecting the operation of the computer, audio equipment, and the like mounted on the vehicle.

Next, a second embodiment will be described. In the active vibration isolator of the present embodiment, as shown in FIG. 3, the coil of the electromagnet 55 is connected between the emitter terminal of the switching device 13 and the ground. The coaxial shielded wire 15 connected to the electromagnet 55 has a core wire 15a.
Is used as a connection line from the emitter terminal on the battery power supply 14 side, and the shield line 15b is used as a connection line on the ground side. That is, the high potential side is connected to the core wire 15a.
By using the ground side as the shield line 15b, noise can be effectively shielded almost in the same manner as in the first embodiment.

Next, a third embodiment will be described. In the active vibration isolator of the present embodiment, as shown in FIG. 4, the coil of the electromagnet 55 is connected between the battery power supply 14 and the collector terminal of the switching device 13. In the present embodiment, the coaxial shield wire 1 connected to the electromagnet 55
As 6, a coaxial shielded wire having two core wires 16 a is used. The two core wires 16a are used as connection lines between the battery power supply 14 side and the collector terminal side and the electromagnet 55, respectively, and the shield line 16b and the ground are connected by connection lines. That is, since the lines through which the pulse signals pass are all the core wires 16a, and the two core wires 16a are surrounded by the shield wires 16b,
In addition, noise can be more effectively shielded as compared with the second embodiment.

In each of the above embodiments, a pulse signal subjected to amplitude modulation is used as a pulse signal.
A width-modulated pulse signal can also be used. Also,
The specific structure of the engine mount is not limited to the structure shown in the above embodiment. Further, in the above embodiment, the case where the present invention is used for the vibration control of the engine mount of the automobile has been described. However, the present invention can also be used for the vibration control of other vibration control target members.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram schematically showing an active vibration isolator according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating an engine mount that is a vibration isolator main body.

FIG. 3 is a block circuit diagram showing a part of an active vibration isolator according to a second embodiment.

FIG. 4 is a block circuit diagram showing a part of an active vibration isolator according to a third embodiment.

[Explanation of symbols]

11: phase adjustment pulse generation device, 12: amplitude modulation device,
13 switching device, 14 battery power, 15 ...
Coaxial shielded wire, 15a: core wire, 15b: shielded wire,
16: coaxial shielded wire, 16a: core wire, 16b: shielded wire, 20: engine mount, 21: first support fitting,
Reference numeral 30: second support fitting, 31: connecting ring fitting, 32: passage forming fitting, 32c: orifice passage, 33: connecting fitting, 34: bottom fitting, 35: rubber elastic body support plate, 36: vibration plate, 41 ... Rubber elastic body, 42: main liquid chamber, 43: sub liquid chamber, 51: yoke member, 55: electromagnet, 56: lead wire, 57: push-up member, 61: power unit, 62: body.

Claims (3)

[Claims] 1. A liquid chamber in which a part of a wall portion is constituted by a main rubber elastic body which is elastically deformed by a vibration input from a member to be damped, and which has a liquid filled therein, and which is displaced by a driving means. A vibration isolator main body in which another part of the wall of the liquid chamber is constituted by a vibration plate, and a control electric signal corresponding to the vibration of the member to be damped is added to the driving means, Vibration control means for controlling the vibrating plate to vibrate by means of a control pulse generator for generating a control pulse signal having a characteristic corresponding to a vibration input from the vibration suppression target member. Means, and switching means for turning on and off in response to the input of the control pulse signal, thereby applying a control electric signal corresponding to the characteristic of the control pulse signal to the drive means to supply power from a power supply. A active vibration damping device forms with the connected drive means directly, as a feeding line provided between the power source and ground, active vibration damping device is characterized in that a coaxial shielded wire. 2. The active vibration isolator according to claim 1, wherein a central core wire of the coaxial shielded wires is connected to a side near a power supply, and an outer shielded wire is connected to a side near a ground. An active vibration isolator characterized by the following. 3. The active vibration isolator according to claim 1, wherein a two-core shield wire is used as the coaxial shield wire, two core wires are used to connect the driving means, and an outer shield wire is used. An active vibration isolator, which is connected to a ground.