JPS59103044A - Power unit mounting device - Google Patents

Abstract

PURPOSE:To prevent the transmission of vibration by connecting the fluid chamber of a mounting unit to a pulsating pressure generating mechanism provided with a chamber contracting by the rotation of an electrically driven motor, thereby to generate a pulse pressure synchronizing with the vibration of the power unit. CONSTITUTION:Fluid chambers 9 and 10 are formed within rubber mounts 6 and 7. One fluid chamber 10 is connected to a chamber 20 of a pulsating pressure generator 16. The capacity of the chamber 25 expands or contracts by the upward and downward movement of a piston 23 by the rotation of the electrically driven motor 26. The electrically driven motor 26 is controlled by a control signal from a control circuit 29, based on a detection signal generated by detecting the rotation of a rotor 23 connected to the crank shaft of the power unit, by a sensor 32. When the fluid chamber 10 is expanded by the relative movement of a frame 5 and a rigid plate 8, the chamber 20 is contracted. When the fluid chamber 10 is contracted, the chamber 20 is controlled to be expanded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mounting device for a power unit, and more specifically, a chamber filled with fluid and whose volume can be changed is defined between the power unit and the vehicle body, and the fluid in the chamber is used to generate a power unit. The present invention relates to a power unit mounting device that provides pulsation pressure synchronized with vibration and prevents pulsation of the power unit from being transmitted to the vehicle body.

In a vehicle, noise within the vehicle interior is caused by vibrations in a relatively high frequency range transmitted from the power unit side. This high-frequency vibration is caused by the vibration that occurs between the power unit (engine) and the vehicle body, especially the vertical vibration caused by the reciprocating movement of the piston of the power unit, or the roll direction caused by the component force of the explosion pressure in the combustion chamber of the power unit. The main component is vibration, and these vibrations have the same frequency as the order component of the rotation speed of the power unit. Such vibrations are transmitted from the power unit to the vehicle interior through the mounting device, resonate within the vehicle interior, and become noise.

For this reason, various mounting devices have been proposed that prevent such high-frequency vibrations from being transmitted to the vehicle interior (vehicle body side), and the present applicant has also proposed
The mounting device shown in the specification of No. 21 is proposed.

The mounting device shown in the specification of Japanese Patent Application No. 119.21/1980 prevents the vibrations in the roll direction mentioned above from being transmitted to the vehicle body, and is arranged on one side of the roll axis of the power unit. The first mounting unit has one end supported by the vehicle body, and a second mounting unit disposed on the other side of the roll axis of the power unit and one end supported by the vehicle body. a first partition connected to the side;
It has a first chamber that is provided between the partition wall and the vehicle body and whose volume increases or decreases due to vibrations of the first partition, and a second chamber that is isolated from the first chamber and whose volume increases or decreases due to vibrations of the first partition. The second mounting unit includes a second partition connected to the other side of the power unit, and a third chamber whose volume increases or decreases due to vibration of the second partition provided between the second partition and the vehicle body. and a fourth chamber that is isolated from the third chamber and whose volume decreases or increases due to vibration of the second partition, and the second and third chambers are connected by a first passage, and the first and fourth chambers are connected by a first passage. are connected by the second passage, and the first
, an incompressible fluid is sealed in the second, third, and fourth chambers and the first and second passages, and a pulsation generating means is connected to the first and second passages, so that a pulsation generating means is connected to the first and second passages. 2nd, 3rd, 4th
Is there a slight roll vibration of the power unit in the room? , based on this, the first
, the second, third, and fourth chambers are configured to send pulsations in phase opposite to the volume changes occurring in the second, third, and fourth chambers. The pulsation generating means has a piston slidably housed in the cylinder to define two chambers, and one of these chambers is connected to the first and second chambers.
The third chamber communicates with the other chamber to the second and fourth chambers. Further, the piston rod fixed to the piston is rotatably connected to a connecting rod rotatably connected to the outer circumference of a pulley having a predetermined diameter R. In the case of a four-cylinder four-cycle engine, this pulley with diameter R is connected via a belt to a pulley with diameter 2R connected to the crankshaft of the power unit, and rotates at twice the angular velocity of the crankshaft.

In the case of a four-cylinder, four-cycle engine, such a pulsation generating means causes the piston to reciprocate within the cylinder twice during one revolution of the crankshaft. In other words, the pulley to which the connecting rod is fixed rotates at twice the angular velocity of the pulley provided on the crankshaft, corresponding to its diameter ratio R/2R, so the reciprocating speed of the piston is twice the rotation speed of the crankshaft. It will be doubled. Therefore, the fluid within each chamber defined within the cylinder has
Pulsation occurs at a frequency twice the rotational speed of the crankshaft, and this pulsation propagates to the 1.3rd and 2.4th chambers, changing the volume of each chamber, causing the vibration of the power unit to change the volume of each chamber. absorbs it and prevents it from being transmitted to the vehicle body.

However, in the pulsation generating means disclosed in Japanese Patent Application No. 57-41921, a piston is slidably housed in a cylinder and defines two chambers communicating with each chamber in the mounting unit. However, this piston is mechanically configured to be driven via a crank mechanism by a pulley having a diameter R and connected by a belt to a pulley having a diameter 2R provided on the crankshaft. For this reason, such a pulsation generating means must accommodate two pulleys that connect the crankshaft and the pulsation generating means and a belt that connects these pulleys in an engine room with relatively little free space. In addition, it interferes with other auxiliary equipment (pumps, alternators, etc.), reducing the degree of freedom in setting their locations.
There is a problem in that workability during assembly is reduced.

In addition, it is difficult for the pulsating pressure generating means with such a mechanical configuration to operate or stop while keeping the generated pulsations synchronized with the vibrations generated by the power unit, which increases the engine speed and causes vibrations to the vehicle body. There is a problem in that when the input becomes small enough not to be a problem, the vibration input due to the pulsation applied to the mounting unit becomes larger.

Furthermore, the propagation speed of pressure waves (fluid pulsations) propagating in a fluid is determined by the type of fluid, and a phase shift occurs between the pulsation generating means and the mounting unit that corresponds to the length of the piping. , this phase shift increases with increasing frequency. For this reason, such a mounting device may be provided with an additional device for correcting this phase shift (proposed in the specification of Japanese Patent Application No. 187507/1987), but this method prevents the above-mentioned pulsation of the mechanical configuration. The problem with the generating means is that it is difficult to provide such an additional device, and it is not possible to substantially correct the phase shift.

The present invention has been made by focusing on such conventional problems, and includes a mounting unit that is interposed between a power unit and a vehicle body, and has a fluid chamber that is filled with fluid and expands and contracts in response to vibration input; A power unit mounting device that prevents vibrations of the power unit from being transmitted to a vehicle body, comprising: a pulsation pressure generation mechanism that applies pulsations to fluid in a fluid chamber in synchronization with vibrations generated in a power unit; includes a sensor that detects the phase of vibration generated in the power unit and outputs a phase signal corresponding to the phase, a control circuit that outputs a control signal whose polarity is inverted in synchronization with the phase signal, and a control circuit that outputs a control signal whose polarity is inverted in synchronization with the phase signal. an electric motor with a rotating shaft rotating in a corresponding direction; a casing; a pulsation pressure generator having a movable member that expands and contracts the chamber by moving by rotation of a shaft, and a control circuit that expands and contracts the volume of the fluid chamber in accordance with this displacement when the power unit approaches the vehicle body. When the power unit is separated from the vehicle body, the movable member moves in a direction that expands or contracts the chamber to correspond to the contraction or expansion of the volume of the fluid chamber corresponding to this displacement. The present invention aims to solve the above-mentioned problems by outputting a control signal to the electric motor at the same time.

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

FIG. 1 is a diagram showing an embodiment of the present invention, and this embodiment is applied to a case where the power unit is a 4-cylinder, 4-cycle engine. First, the configuration will be described. Reference numeral 1 denotes a mounting unit, and the mounting unit 1 is supported by a vehicle body (not shown) via a bracket 2. The mounting unit 1 includes a frame 5 fixed to a bracket 2 and having holes 3.4 formed in the upper and lower walls, two rubber mounts 6.7 fixed to the upper and lower internal ends of the frame 5, and rubber mounts 6.7. A rigid plate 8 is held and fixed therebetween, and the rigid plate 8 is connected to a power unit (not shown). Rubber mount 6.7
A first chamber 9 and a second chamber 10 are respectively formed as fluid chambers, and a rubber plate 13.14 having a protrusion 11.12 acting as a stopper is housed in each chamber 9.10. There is. A hole 3 formed in the upper wall of the frame 5
is closed by a stopper 15, and the first chamber 9 is filled with an incompressible fluid. Further, a fluid chamber 17 communicating with a pulse pressure generator 16 is attached to the hole 4 formed in the lower wall of the frame 5, and an incompressible fluid is injected into the second chamber 10. The pulse pressure generator 16 includes a casing 18 and a diaphragm (movable member) 1 installed inside the casing 18.
A chamber 20 with which the fluid pipe 17 communicates is defined by 9, and the diaphragm 19 is held between retaining plates 21a and 21b and connected to the piston sleeve by bolts 22 together with the retaining plates 21a and 21b. The piston 23 is connected to an arm 28 fixed to a rotating shaft 27 of an electric motor (DC motor) 26 via a rod 24 and a connecting rod 25.
The rotating shaft 27 of the electric motor 26 rotates about the lowest point of the connecting rod 25 so that the arm 28 swings.

When the arm 4 swings due to rotation of the rotating shaft 27, the piston 23 moves up and down, causing the diaphragm 19 to move up and down, and when the diaphragm 19 moves up and down, the chamber 20 expands and contracts. Then, when the chamber 20 is expanded or contracted, the second chamber 10, which is communicated with the fluid pipe I7, is expanded or expanded in the opposite direction.

The electric motor 26 is driven by a control signal of inverted polarity from the control circuit 29, and the rotating shaft rotates in a direction corresponding to the polarity. The control circuit 29 has a comparison circuit 30 and a drive circuit 31, and a rotation speed signal Sn from a sensor 32 is input to the comparison circuit 30. And comparison circuit 3
0 indicates the rotation speed N displayed by the rotation speed signal Sn as the predetermined rotation speed N.
When N≦No, the rotational speed signal Sn is passed through the drive circuit 31, and when N>NO, the rotational speed signal Sn is blocked from passing through the drive circuit 31. Drive circuit 3
1 outputs a current whose polarity is inverted in synchronization with the rotation speed signal Sn to the electric motor 26 as a control signal when the rotation speed signal Sn is input.

On the other hand, the sensor 32 is disposed on the circumferential side of a rotor 33 that rotates in synchronization with the crankshaft, and two sensors are provided on the circumferential side of the rotor 33 at positions corresponding to the crank angle at the time of engine explosion.
permanent magnets 34 are attached. The sensor 32 is a magnetic detection sensor, and when the rotor 33 rotates and the permanent magnet 34 passes through the sensor 32, the sensor 32 detects the magnetism of the permanent magnet 34 and sends the rotation speed signal Sn as a pulse signal to the control circuit. Output to 29. Note that the casing 18, diaphragm 19, chamber 20, retaining plate 21a,
21b.

The bolt 22, the piston shank, the rod 24, the connecting rod 25, and the arm 28 collectively constitute the pulse pressure generator 16, and the pulse pressure generator 16, the electric motor 26, the control circuit 29, and the sensor 32 collectively constitute the pulse pressure generator 16. It constitutes a mechanism 35.

Next, the action will be explained.

When the power unit is a 4-cylinder, 4-stroke engine, explosions occur twice in the nearsyn for one rotation of the crankshaft, and the vibration of the power unit increases accordingly.
This will occur twice. Therefore, the sensor 32 detects the phase and frequency of vibration of the power unit, and the rotational speed signal Sn displays a frequency signal as well as a phase signal.

The control circuit 29 then performs signal processing according to the flowchart in FIG. That is, the comparator circuit 30 calculates the number of rotational speed signals Sn (Hulse number) within a predetermined time to obtain the engine rotational speed N [γpm] (indicating the frequency of vibration of the power unit), and sets this rotational speed N to a predetermined value. Compared to the rotation speed No, when N≦NO, that is, when the frequency of the power unit is below a predetermined value, the rotation speed signal Sn
is passed through the drive circuit 31, and when N>NO, that is, when the frequency of the power unit exceeds a predetermined value, passage of the rotational speed signal Sn to the drive circuit 31 is blocked. When the rotational speed signal Sn is input, the drive circuit 31 outputs a current whose polarity is inverted in synchronization with the rotational speed signal Sn to the electric motor 26 as a control signal, and the rotational shaft 27 of the electric motor 26 changes the polarity of the control signal. Rotate in the direction corresponding to. Then, when the rotating shaft 27 rotates, the arm 28 swings around the lowest point of the connecting rod 25, and when the arm 28 swings, this swing is transmitted to the piston 23 via the connecting rod 25 and the rod 24. The piston 23 moves up and down with the lowest point of the connecting rod 25 as the bottom dead center.

This vertical movement of the piston 23 causes the diaphragm 19 to move up and down, expanding and contracting the chamber 20. As the chamber 20 expands and contracts, the incompressible fluid in the chamber 20 passes through the fluid pipe 17 and flows into the second chamber 10 of the mounting unit 1. Inflow or outflow from the second chamber 10 to the chamber 20. Therefore, chamber 20
As the second chamber 10 expands and contracts, the second chamber 10 conversely contracts and expands. The control signal outputted from the control circuit 29 to the electric motor 26 indicates that the vibration of the power unit is a vibration in the direction indicated by arrow A in FIG. 2, that is, a vibration in a direction in which the second chamber 10 is compressed. The phases are set so that when the chamber 20 is expanded, the chamber 20 is compressed when the vibration is in the opposite direction to the arrow A, that is, when the second chamber 10 is pulled. The phase is set by installing a permanent magnet 34 attached to the rotor 33 at a crank angle near the time of engine explosion, and detecting the magnetism of this permanent magnet 34 to electrically control the electric motor. It controls 26. Therefore, the phase control can be performed accurately and easily. As described above, as the second chamber 10 expands and contracts in synchronization with the vibration input from the power unit, the apparent spring constant of the rubber mount 6 decreases significantly, and the vibration of the power unit
It is absorbed by the change in volume of the chamber 10 and is not transmitted to the vehicle body. Therefore, the muffled noise generated in the vehicle interior due to the vibration of the power unit is reduced. In addition, since the pulsating pressure generator 16 is driven by the electric motor 26 and the electric motor 26 is controlled by the control circuit 29, the pulsating pressure generator 16 is installed in the engine room.
When storing, the degree of freedom in setting the location is increased. Furthermore, when the pulsation of the incompressible fluid propagates through the fluid pipe 17 that communicates the pulsation pressure generator 16 and the mounting unit 1, a patent application is proposed to correct the phase shift that occurs depending on the frequency of the pulsation. The processing device proposed in Sho 56-187507 can be easily provided.

When the engine rotation speed N exceeds a predetermined rotation speed NO at which the vibration of the power unit becomes small and vibration input to the vehicle body becomes a problem, that is, when the frequency of the power unit exceeds a predetermined value, the comparison circuit 30 31, and the drive circuit 31 does not output a control signal to the electric motor 26. Therefore, the electric morph 26 is not driven and the pulse pressure generator 16 does not apply pulses to the incompressible fluid. As a result, when the frequency of the power unit exceeds a predetermined value, the mounting unit 1 is not vibrated conversely, and it is possible to prevent the vibration of the vehicle body and the noise inside the vehicle from worsening. Furthermore, as soon as the engine speed N falls below the predetermined speed NO, pulsations that correctly correspond to the phase of vibration of the power unit can be applied to the fluid chamber.

As described above, according to the present invention, there is provided a mounting unit that is interposed between a power unit and a vehicle body, and has a fluid chamber that is filled with fluid and expands and contracts in response to vibration input; a pulsation pressure generation mechanism that provides pulsation in synchronization with the generated vibration;
In the power unit mounting device that prevents vibrations of the power unit from being transmitted to the vehicle body, the pulse pressure generation mechanism detects a phase of vibrations generated in the power unit and outputs a phase signal corresponding to the phase. A sensor, a control circuit that outputs a control signal whose polarity is reversed in synchronization with a phase signal, an electric morph whose rotating shaft rotates in the direction corresponding to the polarity of the control signal, and a casing that is movably housed within the casing. a pulsation pressure generator having a movable member that communicates with the fluid chamber and defines a chamber filled with fluid, and that is connected to a rotating shaft of the electric morph and moves by rotation of the rotating shaft to expand and contract the chamber; When the power unit approaches the vehicle body, the control circuit shrinks or expands the fluid chamber to correspond to this displacement, and when the power unit moves away from the vehicle body, the control circuit reduces or expands the fluid chamber to correspond to this displacement. A control signal is output to the electric motor so that the movable member moves in the direction of expanding or contracting the chamber in accordance with the contraction or expansion of the chamber, so the chamber of the mounting unit can be expanded or contracted in exact synchronization with the vibration of the power unit. This has the effect of preventing the vibrations of the power unit from being transmitted to the vehicle body and reducing vehicle interior noise. Further, when the power unit is an engine, there is no need to mechanically connect the pulse pressure generator to the crankshaft, which has the effect of increasing the degree of freedom in setting the position. Furthermore, an additional device for phase correction can be easily provided.

In the above embodiment, the pulse pressure generator is stopped when the frequency of the power unit exceeds a predetermined value, so when vibrations in the high frequency range occur, the mounting unit is vibrated and the vehicle body is vibrated. This can prevent the noise inside the vehicle from worsening.

Further, in the above embodiment, pulsation is applied to the fluid chamber IO between the rigid plate 8 connected to the power unit and the vehicle body 2, but pulsation can also be applied to the fluid chamber 9 on the opposite side.

Note that in this case, the phase of the pulsation is opposite to the displacement of the power unit.

[Brief explanation of the drawing]

1.2 are diagrams showing one embodiment of the power unit mounting device of the present invention, FIG. 1 is a partially sectional explanatory view thereof, and FIG. 2 is a flowchart showing the operation of the control circuit.Ba. 1-----Mounting unit, 9.10--
--- Single fluid chamber, 16 --- Pulse pressure generator, 18 --- Casing, 19 --- Diaphragm (movable member), 20 ---
Chamber, 26-------One electric motor, 27-----One rotating shaft, 29-----One control circuit, 32--------Sensor, 35-----One pulse pressure generation mechanism. Patent applicant: Nissan Motor Co., Ltd. Patent attorney Agagun Part 1

Claims (2)

[Claims] (1) A mounting unit that is interposed between the power unit and the vehicle body and has a fluid chamber that is filled with fluid and expands and contracts in response to vibration input, and provides the fluid in the fluid chamber with pulsations that are synchronized with the vibrations generated by the power unit. A mounting device for a power unit throat that prevents vibrations of a power unit from being transmitted to a vehicle body, comprising a pulsation pressure generation mechanism, wherein the pulsation pressure generation mechanism detects a phase of vibrations generated in the power unit, and detects the phase of the vibrations generated in the power unit. a sensor that outputs a phase signal corresponding to the phase signal, a control circuit that outputs a control signal whose polarity is reversed in synchronization with the phase signal, an electric motor whose rotating shaft rotates in a direction corresponding to the polarity of the control signal, and a casing. and a movable member that is movably housed in the casing and communicates with the fluid chamber to define a chamber filled with fluid, and that is connected to the rotating shaft of the electric motor and moves by rotation of the rotating shaft to expand and contract the chamber. a pulse pressure generator having a pulse pressure generator having a control circuit configured to cause the power unit to move away from the vehicle body in a direction that contracts or expands the chamber so as to correspond to the expansion and contraction of the volume of the fluid chamber corresponding to this displacement when the power unit approaches the vehicle body. mounting of a power unit characterized by outputting a control signal to an electric motor so that the movable member moves in a direction that expands or contracts the chamber so as to correspond to the contraction or expansion of the volume of the fluid chamber that corresponds to this displacement. Device. (2) The power unit mounting device according to claim 1, wherein the control circuit includes a comparison circuit that stops outputting the control signal when the number of pulsations of the power unit exceeds a predetermined value.