JPS641332B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a mounting device for a power unit, and more specifically, an elastic body having a pressure receiving chamber filled with fluid is interposed between a vehicle body and a power unit, and a mounting device for mounting a power unit is provided. The actuator applies pressure fluctuations in synchronization with the secondary vibrations to the fluid in the pressure receiving chamber, and controls the actuator so that this pressure fluctuation has an opposite phase to the fluid pressure fluctuations caused by the secondary vibrations, thereby damping the secondary vibrations of the power unit. The present invention relates to a mounting device configured as such.

The mounting device installed between the vehicle body and the power unit is subjected to relatively low-frequency, large-amplitude vibrations from the vehicle body side and high-frequency, small-amplitude vibrations generated by the power unit when the vehicle is running. Ru. The latter high-frequency, small-amplitude vibration is mainly composed of secondary vibrations of the power unit, that is, vibrations caused by the reciprocating motion of the engine's pistons, and this vibration is transmitted to the vehicle body as sound and is transmitted to the vehicle body. This causes the ride quality to deteriorate. For this reason, various mounting devices that dampen this high frequency vibration have been proposed in the past, and for example, one disclosed in US Pat. No. 4,154,206 is known. The structure will be explained based on FIG. 1. Reference numeral 1 denotes an automobile body, a mounting member 2 is fixed to the vehicle body 1, and one end of an elastic member 3 is fixed to the mounting member 2. Reference numeral 4 designates an engine housing (not shown) attached to the vehicle body 1, and a bracket 5 is fixed to the housing 4. The other end of the elastic member 3 is fixed to the bracket 5. A chamber 6 is formed within the elastic member 3, and the chamber 6 is closed by a lid 7 fixed to the elastic member 3. Reference numeral 8 denotes a cylindrical casing having one end fixed to the housing 4, and the casing 8 has a wall portion 10 made of a flexible elastic material.
The opening at one end is closed by the closing plate 1, and the opening at the other end is closed by the closing plate 1.
1 is closed. As a result, a chamber 12 is defined by the casing 8, the wall portion 10, and the closing plate 11. One end of an actuator rod 13 is attached to the wall portion 10, and the other end of the actuator rod 13 is attached to a cam 15 attached to a shaft 14 that rotates in conjunction with the crankshaft of the engine inside the housing 4. is in contact with. These casing 8, wall portion 10, closing plate 11, and actuator rod 13 constitute an actuator 16 as a whole. The chamber 12 of the actuator 16 and the chamber 6 of the elastic member 3 are filled with an incompressible fluid, and the chamber 12 and the chamber 6 are communicated by a conduit 9 filled with the incompressible fluid. There is. In such a configuration, when vibrations generated by the reciprocating motion of the engine piston are transmitted to the elastic member 3 via the housing 4 and the bracket 5, the elastic member 3 expands and contracts between the bracket 5 and the vehicle body 1. do.
This expansion and contraction causes pressure fluctuations in the incompressible fluid within the chamber 6, which propagate as pressure waves through the conduit 9 to the chamber 12 of the actuator 16. On the other hand, since the shaft 14 rotates in communication with the engine crankshaft, the cam 15 also rotates together with it. As a result, the actuator rod 13 in contact with the cam 15 reciprocates according to the cam surface, and the chamber 1
This causes pressure fluctuations in the fluid within 2. This cam 1
5 rotation is the rotation of the engine crankshaft, in other words, the reciprocating movement of the engine piston,
Since it is interlocked with the reciprocating movement, it is synchronized with the expansion and contraction of the elastic member 3 due to the vibration that occurs with the reciprocating movement.
That is, when the elastic member 3 contracts, the flat portion of the cam surface comes into contact with the tip of the actuator rod 13. As a result, the actuator rod 13 moves to the right in the figure due to the elastic restoring force of the wall 10, expanding the chamber 12, causing pressure fluctuations in the fluid in the chamber 12 opposite to those in the chamber 6 of the elastic member 3. let Conversely, when the elastic member 3 that had been contracted expands and returns to its original state, the protrusion on the cam surface moves the actuator rod 13 to the left in the figure, narrowing the chamber 12 and causing the inside of the chamber 12 to narrow. This causes pressure fluctuations in the fluid opposite to those in the chamber 6 of the elastic member 3. in this way,
By absorbing fluid pressure fluctuations generated in the elastic member 3 with the actuator 16, the dynamic spring constant of the elastic member 3 can be reduced. It can even absorb vibrations.

However, in general, the propagation speed of pressure waves propagating in a fluid is determined by the type of fluid, so
A phase shift occurs in the pressure waves between two points separated by a certain distance. This phase shift increases with increasing frequency. For example, the distance between the elastic member and actuator of the engine mount device of a car equipped with a 4-cycle in-line 4-cylinder engine is 1 m.
So, assuming that the fluid is water and the pressure propagation velocity is 1800 m/sec, the engine rotational speed is
Vibration with a frequency of 40 Hz occurs at 1200 rpm, the wavelength of the pressure wave is 45 m, and the phase shift of the pressure wave between the elastic member and the actuator is 8 degrees. Furthermore, when the rotation speed is 2400 rpm, vibrations with a frequency of 80 Hz occur, the wavelength of the pressure wave is 22.5 m, and the phase shift is 16 degrees. As a result, if the actuator rod is actuated in synchronization with the vibration of the elastic member, as is done in the conventional automobile engine mount device as described above, the phase shift of the pressure waves will cause the engine As the rotational speed increases, the actuator becomes unable to completely absorb the pressure fluctuations of the incompressible fluid generated in the elastic member, that is, it becomes unable to absorb the high-frequency vibrations of the engine, leading to the generation of muffled noise. It was hot.

The present invention has been made by focusing on such conventional problems. a pressure receiving chamber defined within the member so as to be able to change its volume and filled with fluid;
vibration detection means that outputs a signal synchronized with the secondary vibration of the power unit; and vibration detection means that operates according to a predetermined control signal and detects pressure fluctuations at the same frequency as the secondary vibration of the power unit and whose phase is controlled. and an actuator that generates the pressure fluctuation and applies the pressure fluctuation to the fluid in the pressure receiving chamber through the fluid in the conduit having a predetermined length, and the pressure that propagates through the length of the conduit and the fluid interposed within the conduit. In order to solve the above-mentioned problems, the present invention is provided with a phase matching circuit that delays a signal from the vibration detection means in accordance with the wave propagation speed and outputs the delayed signal as the predetermined control signal. There is.

The present invention will be explained below based on the drawings.

FIG. 2 to FIG. 4 are diagrams showing an embodiment of the present invention.

First, to explain the configuration, 21 is the car body,
Reference numeral 22 denotes a bracket provided on the housing of the power unit (not shown), and a mount 23 is interposed between the vehicle body 21 and the bracket 22. This mount 23 is attached to the bracket 2
A frame body 26 is fixed to the vehicle body 21 with bolts 24 and nuts 25, and a frame body 29 is similarly fixed to the vehicle body 21 with bolts 27 and nuts 28. The elastic member 30 is fixed to the bodies 26 and 29 with an adhesive or vulcanization adhesive. The elastic member 30 is formed with a hollow recess 30a that is open at the top in the figure.
A pressure receiving chamber 31 is defined together with a recess 26a formed in the upper frame 26 and opened at the bottom. This pressure receiving chamber 31 is filled with incompressible fluid, and
The volume changes according to the deformation of the side wall 30b extending from the elastic member 30 and defining the recess 30a.
Further, the upper frame body 26 is provided with an air vent valve 32 and a joint 33 connected to an actuator to be described later, and these valves 32 and joints 33 open into the pressure receiving chamber 31.

34 is a restraining plate provided on the outer periphery of the side wall 30b of the elastic member 30. This restraint plate 34
When the power unit and the side wall 30b are displaced, the side wall 30b
This restricts the expansion and contraction of the side wall 30b by preventing the expansion and invagination of the side wall 30b. Further, a part of this restraint plate 34 forms a stopper 34a bent downward,
A rubber-like elastic body 35 is clamped between the mount 23 and the lower frame 29 to prevent excessive displacement of the mount 23.

36 is a hydraulic pressure generator connected to a pressure receiving chamber 31 defined in the elastic member 30 via a joint 33 and a conduit 37. The hydraulic pressure generator 36 includes a cylinder body 38, and is slidably housed within the cylinder body 38 and has two parts inside the cylinder body 38.
Piston 39 defining two chambers 38a, 38b
and a spring 40 housed in the chamber 38b open to the outside air and urging the piston 39 toward the other chamber 38a with a predetermined elastic force. This other chamber 38a is connected to the pressure receiving chamber 3 via the conduit 37.
1 and is filled with an incompressible fluid together with a conduit 37. Therefore, when the volume of the chamber 38a changes with the movement of the piston 39, and a pressure fluctuation occurs in the fluid within the chamber 38a,
This pressure fluctuation is transmitted to the pressure receiving chamber 31 via the conduit 37. Further, the spring 40 is loosely inserted into the piston 39 and the cylinder body 38
One end of a piston rod 41 protruding outside is fixed, and the other end of this piston rod 41 is attached to the vibrator 4.
2 is engaged. This vibrator 42 has a solenoid 42a driven by a control means to be described later, vibrates the piston rod 41, transmits this vibration to the piston 38, and displaces the piston 39. The spring 40 applies pressure to the fluid in the pressure receiving chamber 31 against the load applied to the mount 23 when the power unit is statically fixed. These hydraulic pressure generator 36 and vibrator 42 constitute an actuator 43.

Reference numeral 44 denotes a vibration detection means that outputs a signal synchronized with the rotation of the power unit, and this vibration detection means 44 outputs, for example, a plurality of pulse signals (two in this embodiment) per revolution of the crankshaft. A crank angle sensor or distributor is used to output this pulse signal A.
is output to the phase matching circuit 45. Phase matching circuit 4
5 is a waveform shaping circuit 46 that shapes the waveform of the pulse signal A output from the vibration detection means 44, as shown in the block diagram of FIG. 3 and the timing chart of FIG. 4 showing the output waveforms of each circuit; The phase of the signal B output from the waveform shaping circuit 46 is determined by the pressure propagation velocity of the fluid filled in the conduit 37,
a delay circuit 47 that delays in accordance with the length of the pipe 7 and the rotational speed of the power unit; and a duty circuit that outputs the trigger pulse signal C output from the delay circuit 47 as a square wave signal D having a predetermined pulse width. It is composed of a ratio setting circuit 48. Further, the signal output from the phase matching circuit 45, that is, the signal D output from the duty ratio setting circuit 48, is input to the switching circuit 49, and the switching circuit 49 is activated. The switching circuit 49 connects the power supply circuit 50 and the vibrator 42 in synchronization with the signal D, and applies a drive voltage indicated by the signal E in FIG. 4 to the solenoid 42a to excite it. That is, the vibrator 42 is controlled by the phase matching circuit 45 to drive the hydraulic pressure generator 36, so that when the pressure fluctuation generated by the hydraulic pressure generator 36 reaches the pressure receiving chamber 31, the vibration exciter 42 drives the hydraulic pressure generator 36. This results in synchronization with the fluid pressure fluctuations caused by secondary vibrations of the power unit, with an opposite phase. Note that each of the waveform shaping circuits 46 and delay circuits 4 described above
7. The duty ratio setting circuit 48 and the switching circuit 49 receive power from the power supply circuit 50.

In the case of a mounting device having such a configuration, while the power unit is rotating, due to the reciprocating movement of the piston of the engine, there is a two-way motor with a frequency twice the number of rotations of the power unit. Next vibration is applied. Therefore, the elastic member 30 expands and contracts due to this vibration, causing a volume change in the pressure receiving chamber 31, and a pressure fluctuation occurs in the fluid within the pressure receiving chamber 31 with a frequency twice the rotational speed of the power unit. Further, the vibration detection means 44 also transmits a signal A of the same frequency synchronized with the rotation of the power unit to the phase matching circuit 44.
5, and the actuator 43 is driven.
However, the hydraulic pressure generator 36 of the actuator 43
As mentioned above, the pressure fluctuation of the fluid that occurs is transmitted via the conduit 37 as a synchronized and opposite phase pressure fluctuation within the pressure receiving chamber 31 with the fluid pressure fluctuation that occurs in the pressure receiving chamber 31 due to the vibration of the power unit. .
Therefore, when the power unit and the vehicle body 21 are displaced in the direction of separation, the elastic member 30 is expanded, and the fluid pressure in the pressure receiving chamber 31 fluctuates to the low pressure side, the pressure fluctuation caused by the actuator 43 is transferred to the conduit 37. It reaches the pressure receiving chamber 31 in a phase on the high pressure side. Therefore, the pressure fluctuations cancel each other out, and the displacement between the power unit and the vehicle body 21 is attenuated. Similarly, when the power unit and the vehicle body 21 are displaced in the direction toward each other, the elastic member 30 contracts, and the fluid pressure in the pressure receiving chamber 31 fluctuates toward the high pressure side, the pressure fluctuation caused by the actuator 43 is conduit 37
It reaches the pressure receiving chamber 31 with a phase on the low pressure side, and absorbs pressure fluctuations caused by vibrations of the power unit. In this way, the pressure fluctuation of the fluid in the pressure receiving chamber 31 caused by the deformation of the elastic member 30 due to the secondary vibration of the power unit causes the actuator 43 to be driven by a signal whose phase is matched by the phase matching circuit 45. This is offset by the pressure fluctuations caused by
It becomes possible to reduce the dynamic spring constant of the elastic member 30, and thereby the elastic member 30 becomes able to buffer even higher frequency vibrations.

Other embodiments are shown in FIGS. 5 and 6, respectively. Note that the same parts as those of the power unit mounting device shown in FIGS. 2 to 4 are designated by the same numbers, and explanations and illustrations thereof will be omitted.

In the power unit mounting device shown in FIG. 5, a hydraulic generator 36 is mounted on an elastically deformable metal bellows 51, and both ends of the metal bellows are closed liquid-tightly to define a chamber 52 together with the metal bellows 51. It is constituted by end covers 53 and 54 that form the same. A rod 55 that engages with the vibrator 42 is engaged with one end cover 53, and the other end cover 54 connects the conduit 37 with a flare nut 54' to communicate the chamber 52 and the pressure receiving chamber 31. are doing. Therefore, when the vibrator 42 is driven, the metal bellows 51
is deformed to cause a volume change in the chamber 52, and fluid pressure fluctuations due to this volume deformation are transmitted to the pressure receiving chamber 31 via the conduit 37. In addition, in this chamber 52,
The mount 23 is filled with pressurized fluid to counteract the load of the power unit applied to the mount 23 during static settling. Other configurations and operations are similar to those of the previous embodiment.

Furthermore, the power unit mounting device shown in FIG.
56', a diaphragm 58 fluid-tightly fixed by an O-ring 61 to define a chamber 57 communicating with the pressure receiving chamber 31; a rod 59 fixed to the diaphragm 58 and engaged with the vibrator 42; 58 and a spring 60 that biases the chamber 57 in the direction in which it is compressed. Also in this hydraulic generator 36, when the vibrator 42 is driven, the diaphragm 58 is deformed via the rod 59. Therefore, the chamber 57 undergoes a volume change, causing a pressure fluctuation in the fluid, and this pressure fluctuation is transmitted to the pressure receiving chamber 31 via the conduit 37. Note that the spring 60 applies pressure to the fluid in the chamber 57 that counteracts the load of the power unit applied to the mount 23 during static settling.

According to the oil pressure generators 36 shown in FIGS. 5 and 6, the chambers 52 and 5 of each oil pressure generator 36 are
7 is sealed by the metal bellows 51 or the diaphragm 58, a highly reliable hydraulic generator 36 with less risk of fluid leakage can be obtained.

As explained above, according to this invention,
an elastic member that is interposed between the vehicle body and the power unit and expands and contracts in response to secondary vibrations of the power unit; a pressure receiving chamber that is defined within the elastic member so as to be able to change its volume and is filled with fluid; vibration detection means that outputs a signal synchronized with the secondary vibration of the power unit; and vibration detection means that operates according to a predetermined control signal and detects pressure fluctuations at the same frequency as the secondary vibration of the power unit and whose phase is controlled. and an actuator that generates the pressure fluctuation and applies the pressure fluctuation to the fluid in the pressure receiving chamber through the fluid in the conduit having a predetermined length, and the pressure that propagates through the length of the conduit and the fluid interposed within the conduit. Since the power unit mounting device is equipped with a phase matching circuit that delays the signal from the vibration detection means in accordance with the wave propagation speed and outputs the delayed signal as the predetermined control signal, the elastic It becomes possible to reduce the dynamic spring constant of the member, thereby achieving the effect that the elastic member can improve its ability to absorb vibrations in a higher frequency range.

In addition, in the power unit mounting device shown in Figures 5 and 6, the actuator chambers communicating with the pressure receiving chamber are sealed with metal bellows or diaphragms, eliminating the risk of fluid leakage. , a more reliable mounting device can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a conventional power unit mounting device, and FIG. 2 is a schematic cross-sectional view of a power unit mounting device according to an embodiment of the present invention together with an electric circuit.
FIG. 3 is a block diagram showing in detail the electrical circuit portion of the power unit mounting device of FIG. 2;
FIG. 4 is a timing chart showing the operation of the electrical circuit shown in FIG. 3 together with its output waveform, and FIG. 5 is a sectional view showing in detail the actuator of a power unit mounting device according to another embodiment of the present invention. and FIG. 6 is a sectional view showing in detail an actuator of a power unit mounting device according to still another embodiment of the present invention. 21...Vehicle body, 22...Bracket (power unit), 23...Mount, 30...Elastic member,
31... Pressure receiving chamber, 43... Actuator, 44
... Vibration detection means, 45 ... Phase matching circuit.

Claims (1)

[Claims] 1. An elastic member that is interposed between the vehicle body and the power unit and expands and contracts in response to secondary vibrations of the power unit, and a pressure receiving chamber that is defined within the elastic member so as to be able to change its volume and is filled with fluid. , a vibration detection means that outputs a signal synchronized with the secondary vibration of the power unit, and a pressure fluctuation that operates according to a predetermined control signal and has the same frequency as the secondary vibration of the power unit and whose phase is controlled. and an actuator that generates the pressure fluctuation and applies the pressure fluctuation to the fluid in the pressure receiving chamber via the fluid in the conduit having a predetermined length, and propagates the length of the conduit and the fluid interposed in the conduit. A mounting device for a power unit, comprising a phase matching circuit that delays a signal from the vibration detection means in accordance with the propagation speed of a pressure wave and outputs the delayed signal as the predetermined control signal.