JP2001153176A - Engine mount - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine mount for preventing the transmission to a car body of high frequency vibration generated in a hydraulic actuator by actuation of a solenoid valve by arranging a rubber mount between the hydraulic actuator and a car body frame. SOLUTION: Since oil pressure is supplied to or released from a chamber 17 of a hydraulic actuator 6 functioning as an active mount by an hydraulic pressure supply device provided with the solenoid valve actuated in a high frequency, the hydraulic actuator 6 generates vibration of the frequency and the higher harmonic wave. Since a rubber mount 4 is arranged on the car body frame 3 side of the hydraulic actuator 6, the transmission of vibration of a high frequency transmitted to a car body frame 3 generated by the hydraulic actuator 6 is damped by the rubber mount 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine mount for supporting an engine in a vehicle such as an automobile.

[0002]

2. Description of the Related Art When mounting an engine on a vehicle body,
2. Description of the Related Art In order to prevent engine vibration and noise from being transmitted to a vehicle body, a mount made of a vibration-proof rubber called a rubber mount has been conventionally used. However, the magnitude of the generated vibration and noise not only depends on the operating condition of the engine, but also there are large vibrations, fine and fast repeating vibrations, and various directions of vibration. However, it is not possible to solve all the phenomena that are problematic in supporting the engine.

[0003] Phenomena that are problematic in supporting the engine include hiccups and shakes that vibrate at a relatively low frequency, and muffled sounds (in-vehicle sounds) that vibrate at a relatively high frequency. The muffled sound is the vibration of the order (harmonic) component synchronized with the engine speed, which is caused by the relatively small amplitude vibration of the engine and the drive system. This vibration is transmitted to the vehicle body via the rubber mount and This is a phenomenon that generates resonance.

[0004] In supporting the engine, idle vibration, which tends to occur during idling operation of the engine, becomes a problem in addition to hiccups, shakes, and muffled sounds. Idle vibration is caused by the fact that the rolling resonance frequency of the engine matches the frequency of vibration due to the number of revolutions of the engine, and is particularly problematic in a horizontally mounted engine vehicle.

[0005] The applicant of the present invention first attaches a rubber mount to an engine, and a cylinder mounted on a vehicle body and a hydraulic pressure which is provided to be relatively movable in the cylinder and is supplied to a chamber formed in the cylinder. An actuator is constituted by a piston that applies a displacement to the rubber mount under the action of the above, and the electromagnetic pressure in the chamber is actively controlled by an electromagnetic valve to cancel the vibration force from the engine to the vehicle, and a torque fluctuation detecting means By stopping the control of the oil pressure by the open / close command signal from the controller when the detected torque fluctuation of the detected engine reaches a predetermined high frequency range and absorbing the vibration by the rubber mount,
Able to reduce room noise (muffled sound) mainly at idle speed and engine speed near idling, and to reduce vibration and noise by absorbing vibration of high frequency components by the rubber mount placed above the actuator. (Japanese Patent Application No. 10-204060).

FIG. 4 is a sectional view of a conventional engine mount. Engine mount 40 shown in FIG.
Is composed of a rubber mount 4 disposed on the engine bracket 2 side and a hydraulic actuator 6 disposed on the vehicle body frame 3 side. The rubber mount 4 includes a mount rubber 4a and an end plate 4 attached to an end surface thereof.
d and 4e, and is attached to the engine bracket 2 on one side, and an attachment plate 19 is attached on the other side. The hydraulic actuator 6 includes an actuator body 7 and a piston 10 slidably disposed on the actuator body 7. The actuator body 7 includes a cylinder 8 attached to the vehicle body frame 3 and a cover 9 attached to the cylinder 8 with fixing bolts 9c so as to cover the opening 8a of the cylinder 8. The piston 10 is provided in the cylinder 8 so as to be relatively movable, and supports a load applied to the rubber mount 4 via the mounting plate 19 under the action of hydraulic pressure supplied to a chamber 17 in the cylinder 8. In this example, the piston 10 is fixed to a mounting plate 19 of the rubber mount 4.

The cylinder 8 has a cylindrical shape, and the bottom is attached to the body frame 3 via a force sensor 14. The outer peripheral portion 13b of the annular rubber 13 is vulcanized and bonded to the opening 9b of the cover 9, and the piston 10 is vulcanized and bonded to the inner peripheral portion 13a of the annular rubber 13. The piston 10 is relatively movable with respect to the actuator body 7 by the elastic deformation of the annular rubber 13. Ring rubber 1
3 is a chamber 1 formed in the actuator body 7
7 has a function of sealing the inside. The piston 10
A flange-shaped stopper 18 is provided, and the stopper 18 can contact the lower surface 9 a of the cover 9. A communication pipe 22 connected to a hydraulic circuit described later is connected to a side wall of the cylinder 8. When a large external force is applied to the piston 10,
By the lower end surface 12 of the piston 10 abutting on the bottom surface 16 of the cylinder 8, the retreat position of the piston 10 is regulated, and excessive deformation of the annular rubber 13 is prevented. When the oil pressure is not supplied to the chamber 17, the piston 10 is in contact with the bottom surface 16. However, when the engine starts, the oil supplied to the chamber 17 increases the oil pressure in the chamber 17, and the piston 10 The lower end surface 12 is separated from the bottom surface 16 and the engine load is supported by the oil pressure in the chamber 17. When detecting a torque fluctuation that causes engine vibration, instead of the force sensor 14, a pressure sensor that detects the oil pressure in the chamber 17 or a signal that is triggered once every two rotations of the engine output shaft such as a cam pulse is triggered. May be used.

The engine mount shown in FIG. 4 is controlled by a hydraulic circuit disclosed in Japanese Patent Application No. 10-204060 as shown in FIG. 5, for example. FIG.
FIG. 5 is a block diagram illustrating an example of a hydraulic pressure supply device that supplies a hydraulic pressure to the engine mount illustrated in FIG. 4. As shown in FIG. 5, a hydraulic circuit for supplying / discharging the hydraulic pressure to / from the hydraulic actuator 6 includes a reservoir 20 containing oil.
And a hydraulic pump 2 for pumping oil from the reservoir 20
1, a holding valve 23 disposed on a hydraulic pipe extending from the hydraulic pump 21 to the connecting pipe 22, and a pressure reducing valve 25 disposed on a hydraulic pipe 24 connected from the connecting pipe 22 at a point A and reaching the reservoir 20. It is configured. The holding valve 23 and the pressure reducing valve 25 are, for example, solenoid valves capable of controlling the flow rate by changing the ON / OFF duty ratio. The hydraulic pump 21 serving as a hydraulic pressure source generates a pressure higher than the pressure corresponding to the maximum value of the dynamic load of the engine applied to the hydraulic actuator 6 (that is, the load obtained by adding the static load and the dynamic load fluctuation). It is a pump that can do.

Since the hydraulic actuator 6 receives a force from the engine bracket 2 due to the torque fluctuation of the engine output, the fluctuation of the hydraulic pressure generated in the hydraulic actuator 6 is transmitted to the vehicle body frame 3, and the vibration and noise are transmitted to the vehicle body. Will be. The controller 26 receives a trigger signal generated as a pulse signal once for every two rotations of the engine output shaft with the operation of the cam from the engine E, and issues a command signal corresponding to the operation timing of the engine E to the holding valve 23. And output to the pressure reducing valve 25. Holding valve 23
Is closed, and the pressure in the hydraulic actuator 6 is decreased by controlling the pressure reducing valve 25 to be opened. By controlling the holding valve 23 to be opened and the pressure reducing valve 25 is closed, the hydraulic pressure in the hydraulic actuator 6 is increased. .

The controller 26 receives the trigger signal from the engine E and controls the opening and closing of the holding valve 23 and the pressure reducing valve 25 so that the force generated between the engine bracket 2 and the body frame 3 is reversed in phase. Is applied to the hydraulic actuator 6. That is, when the engine vibrating force is downward with respect to the mount, the rubber mount 4 is about to be compressed. Therefore, the hydraulic pressure in the chamber 17 is released, and the force transmitted to the vehicle body so that the rubber mount 4 is not bent. Offset. When the vibration of the engine is upward with respect to the mount, the rubber mount 4 tends to be pulled. Therefore, the hydraulic pressure is supplied into the chamber 17 so that the rubber mount 4 is transmitted to the vehicle body so as not to bend. Offset the power of As a result, the hydraulic actuator 6 supports the static load of the engine and reduces the exciting force on the vehicle body frame 3.

[0011]

In an active engine mount (hereinafter abbreviated as ACM) which supports dynamic load fluctuations of an engine by actively controlling the hydraulic pressure supplied to a hydraulic actuator, control is not required. Due to the pressure fluctuation of hydraulic oil caused by the operation of the solenoid valve used,
The ACM itself may be the new relatively high frequency vibration source. FIG. 5 shows a control signal supplied to an electromagnetic valve such as the holding valve 23 and the pressure reducing valve 25 and a force generated by the hydraulic actuator on the mount by the control signal in the hydraulic supply device for supplying hydraulic pressure to the engine mount shown in FIG. The graph is shown in FIG. This control signal is a signal for canceling the primary component of the explosion corresponding to the vibration of the engine generated in the idling operation state.
As shown in FIG. 6A, since the signal is a signal that is repeatedly turned on and off at a duty ratio of about 5 msec, control is performed.
As shown in (b), the low frequency (25
Hz) In addition to the vibration, an exciting force of a frequency around 200 Hz and its harmonic component is generated.

FIG. 7 shows an experimental result showing the relationship between the volume of the chamber of the hydraulic actuator and the high frequency component of the generated vibration. As can be seen from the graph shown in FIG. 7, the larger the volume of the chamber, the smaller the effect on the generation of vibration. That is, FIGS. 7 (a), (b), (c),
(D) shows chamber volumes of 10 ml and 40 m, respectively.
For 1, 80 ml and 100 ml, the pressure when the hydraulic actuator is not operated (corresponding to the supply pressure) and the pressure fluctuation generated in the chamber when the hydraulic actuator is operated are shown. As can be understood from FIGS. 7A and 7B, the larger the volume of the chamber, the smoother the curve of the pressure fluctuation, and the less the high frequency component.
Therefore, it can be said that a large hydraulic actuator is preferable. However, since the shape of the chamber is limited in terms of mounting on an engine and mounting on a vehicle, it is actually difficult to increase the bulk of the hydraulic actuator. is there.

Therefore, a rubber mount for attenuating high frequency components of vibration and a hydraulic actuator for attenuating low frequency components of vibration are provided. There is a problem to be solved as to how to prevent transmission to the vehicle body.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to reduce transmission of vibration of a harmonic vibration component generated by a hydraulic actuator to a vehicle body without increasing the size of an ACM. It is to provide an engine mount that allows the engine mount to be driven.

According to the present invention, a cylinder having a chamber to which hydraulic pressure is supplied is provided, and an engine is provided at the upper end of the cylinder so as to be relatively movable, and an engine is attached to an upper end thereof. The present invention relates to a hydraulic actuator including a piston for supporting the engine, and an engine mount including a rubber mount disposed between the hydraulic actuator and a vehicle body.

According to this engine mount, the ACM composed of the hydraulic actuator is provided on the engine side, and the rubber mount for vibration isolation is arranged on the vehicle body side.
Since the vibration of the high frequency component generated by the hydraulic actuator is attenuated by the rubber mount when it is transmitted to the vehicle body side, the vibration of the high frequency component transmitted to the vehicle body side is reduced.

In this engine mount, the cylinder is formed so that a center line of the piston or the cylinder protrudes in a direction of an extension extending toward the rubber mount, and the rubber mount sandwiches the extension. And at least one pair of mounting rubbers disposed on both sides of the mounting rubber, and mounting surfaces of the mounting rubber and the cylinder are inclined inwardly with respect to a direction in which the extension line extends. That is, the mount rubber is attached at an angle from the horizontal direction of mounting the engine (the direction of the mounting surface on the vehicle side parallel to the road surface on which the engine is mounted when the vehicle is placed on a horizontal road surface), The vibration of the engine is absorbed by the compression and shear deformations of the mount rubber, and the appropriate vibration damping action is exhibited in the vertical and horizontal directions. According to this arrangement, the cylinder is formed in a shape protruding in the direction of extension of the center line of the piston toward the vehicle body, so that the overall height of the engine mount is reduced as much as possible and the chamber is restricted within the constraints of interference with other parts. As much as possible, and the generation of harmonics can be suppressed.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an engine mount according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional view showing an embodiment of an engine mount according to the present invention, and FIG. 2 is a graph showing a vehicle interior sound in the embodiment shown in FIG. 1 together with a comparative example.

In FIG. 1, components having the same functions as those used in the conventional engine mount shown in FIG. 4 are assigned the same reference numerals as those shown in FIG. Referring to FIG. 1, the engine mount 1 according to the present invention shown in FIG. 1 is basically different from the engine mount 40 shown in FIG. 4 in that the rubber mount 4 and the hydraulic actuator 6 are arranged upside down. I have. That is, the engine mount 1 includes a hydraulic actuator 6 provided on the engine bracket 2 side, and a rubber mount 4 provided on the vehicle body frame 3 or a bracket attached to the vehicle body frame 3. The rubber mount 4 includes a pair of mount rubbers 4a, and upper and lower brackets 4b and 4c respectively attached to upper and lower end surfaces thereof. The upper bracket 4b is attached to the hydraulic actuator 6, The bracket 4c is attached to the vehicle body frame 3.

The hydraulic actuator 6 includes an actuator body 7 and a piston 1 slidably mounted on the actuator body 7 and fixed to the engine bracket 2.
0. The actuator body 7 includes a cylinder 8 attached to the rubber mount 4 and a cover 9 that covers the opening 8a of the cylinder 8 and is fixed to the cylinder 8 with fixing bolts 9c. The piston 10 is provided so as to be relatively movable in the cylinder 8, and supports the load of the engine E via the engine bracket 2 under the action of the hydraulic pressure supplied to the chamber 17 in the cylinder 8.

The cylinder 8 has a cylindrical shape, and the bottom is attached to the upper bracket 4 b of the rubber mount 4. The piston 10 is relatively movable with respect to the opening 9 b of the cover 9 via an O-ring 15 while maintaining a sealed state. In addition, as a sealing means for sealing the inside of the chamber 17 formed in the actuator body 7, a structure other than the O-ring 15 can be used. Piston 10
Is provided with a stopper 18 in the form of a collar, and the stopper 18 can contact the lower surface 9 a of the cover 9. A communication pipe 22 connected to a hydraulic circuit described later is connected to a side wall of the cylinder 8. When a large external force is applied to the piston 10, the lower end surface 12 of the piston 10
, The retracted position of the piston 10 is regulated.

When no oil pressure is supplied to the chamber 17, the piston 10 abuts on the bottom surface 16 and the engine E
Is transmitted to the bottom of the cylinder 8, but when the engine E is started, the oil supplied into the chamber 17 increases the oil pressure in the chamber 17, the lower end surface 12 of the piston 10 separates from the bottom surface 16, and the engine load is reduced. Is chamber 1
It is supported by the hydraulic pressure in 7. The supply of the hydraulic pressure of the hydraulic actuator 6 can be performed by a hydraulic circuit shown in FIG. 5, and the configuration and operation thereof will not be described again. When detecting a torque fluctuation that causes the vibration of the engine E, a signal such as a cam pulse generated once for every two rotations of the engine output shaft is provided between the vehicle body frame 3 and the rubber mount 4. Force sensor and chamber 17
It may be a pressure sensor that detects the oil pressure in the inside.

FIG. 2 shows the level of in-vehicle sound according to the frequency of the engine mount according to the present invention and the comparative example. In FIG. 2, a curve C is a graph showing a frequency distribution of the in-vehicle sound when the hydraulic actuator 6 which is an ACM is turned off. In the high frequency region, the level occupying the in-vehicle sound is low, but in the low frequency region, the peak is high, which indicates that the attenuation of the low frequency component of the vibration is not sufficient. A curve B is an engine mount 40 in which the rubber mount 4 as shown in FIG.
6 is a graph showing the frequency distribution of the in-vehicle sound when the operation of the hydraulic actuator 6 is turned ON. The engine mount shown by the curve B has an effect of lowering the peak value of the above-mentioned rotation secondary component as shown by the width F of the in-vehicle sound in the low frequency region as compared with the curve C. That is, although the peak value at the idle frequency of 25 Hz is reduced, the peak values of the vibrations at the harmonics of 50 Hz and 75 Hz are not controlled, so there is no difference from the curve C. On the other hand, in the engine mount shown by the curve B, a high peak value is generated in the high frequency region, which indicates that the vibration of the high frequency component occurs due to the operation of the hydraulic actuator 6.

A curve A shows the level of the in-vehicle sound when the operation of the hydraulic actuator 6 is turned on for the engine mount 1. As can be seen from curve A,
This engine mount 1 has an idle frequency of 25
Although the peak value at Hz is reduced, its harmonics at 50 Hz and 75 Hz are not controlled and have no difference from curve C, which is similar to curve B. On the other hand, in the high frequency region, the vibration at the frequency and its higher harmonics near 200 Hz has reduced the peak value, and it can be seen that the vibration of the high frequency component is greatly reduced.

FIG. 3 is a longitudinal sectional view showing another embodiment of the engine mount according to the present invention. In the engine mount shown in FIG. 3, components having the same functions as those used in the engine mount shown in FIG. 1 are denoted by the same reference numerals as those shown in FIG. Description is omitted. The engine mount 30 shown in FIG.
Similarly to the above, the rubber mount 4 is provided at the lower part, and the hydraulic actuator 36 is provided at the upper part. The cylinder 38 constituting the actuator body 37 of the hydraulic actuator 36 has a bottom section narrowing toward the vehicle body frame 3. It is formed in a shape protruding so as to fit in.

Rubber mount 3 of engine mount 30
4 is also arranged obliquely with respect to the extension line DD of the center line of the piston 10 in accordance with the cylinder 38 formed in a shape protruding downward. That is, the mounting surface 38a, which is the lower surface of the cylinder 38, is formed on a slope, and the upper surface 34d of the bracket 34c facing the mounting surface 38a of the cylinder 38 is also formed on a slope equidistant from the mounting surface 38a. ing. Mounting surface 3 of cylinder 38
A pair of mount rubbers 34a, 34a are preferably disposed symmetrically with respect to the extension line DD between the upper surface 8d and the upper side surface 34d of the bracket 34c. Bracket 3
4c is fixed to the body frame 3 with fixing bolts 34e. The upper mounts of the two mount rubbers 34a, 34a are directly bonded to the mounting surface 38a of the cylinder 38. Although the mounting surface 38a needs to be inclined to bond the mount rubbers 34a, 34a, the space formed inside the cylinder protruding downward can increase the volume of the chamber 17. As a result, the displacement of the piston 10 in the downward direction is absorbed also in the enlarged portion of the chamber 17, so that the overall height of the engine mount can be reduced.

The mount rubber 34a is mounted on a horizontal mounting surface of the engine E (when the vehicle is placed on a horizontal road surface, the mounting surface on the vehicle side parallel to the road surface on which the engine is mounted, for example, the upper surface 3a of the body frame 3). Direction). The rubber mount 34 is advantageous as a mechanically stable engine mount that always returns toward the extension line DD of the center line of the piston 10 even if a deformation occurs between the hydraulic actuator 6 and the body frame 3. Characteristics. The vibration of the engine E is absorbed by the compression deformation and the shear deformation of the mount rubber 34a,
Appropriate vibration damping action is exhibited in the vertical and horizontal directions. Also,
Since the cylinder 38 is formed in a shape projecting downward, the volume of the chamber 17 can be made as large as possible within the constraints of interference with other components. Furthermore, the total height from the tip of the piston 10 to the lower part of the rubber mount 4 can be reduced as much as possible.

[0028]

Since the present invention is configured as described above, it has the following effects. That is, according to this engine mount, the ACM comprising the hydraulic actuator
Since the rubber mount is provided on the engine side and the rubber mount is disposed on the vehicle body side, the vibration of the high frequency component generated by the hydraulic actuator is attenuated by the rubber mount when transmitted to the vehicle body side. It is possible to prevent a high frequency component of vibration generated due to the operation from being transmitted to a cabin or the like of the vehicle. Further, the ACM as a whole can be reduced in size, and the degree of freedom in layout on the mounting space can be increased.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of an engine mount according to the present invention.

FIG. 2 is a graph showing an in-vehicle sound in the embodiment shown in FIG. 1 together with a comparative example.

FIG. 3 is a longitudinal sectional view showing another embodiment of the engine mount according to the present invention.

FIG. 4 is a longitudinal sectional view showing an example of a conventional engine mount.

FIG. 5 is a hydraulic circuit diagram showing an example of a hydraulic supply device applied to the engine mount shown in FIG.

6 is a graph showing a control signal supplied to an electromagnetic valve in the hydraulic supply device shown in FIG. 5 and a force generated by a hydraulic actuator on a mount by the control signal.

FIG. 7 is a graph showing a relationship between a volume of a chamber of a hydraulic actuator and a high-frequency component of generated vibration.

[Explanation of symbols]

 1, 30 Engine mount 3 Body frame 4, 34 Rubber mount 4a, 34a Mount rubber 6, 36 Hydraulic actuator 8 Cylinder 10 Piston 17 Chamber 38a Mounting surface E Engine DD Extension line of center line of piston

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Mitsuo Nakano 8th Tsuchiya, Fujisawa-shi, Kanagawa F-term in Isuzu Central Research Institute Co., Ltd. 3D035 CA04 CA05 3J048 AA02 BA09 BB10 BE03 CB22 DA03 EA01

Claims (2)

[Claims] 1. A cylinder having a chamber to which a hydraulic pressure is supplied, and an engine mounted on an upper end of the cylinder so as to be relatively movable in the cylinder and receiving an action of the hydraulic pressure supplied to the chamber to receive the engine. And an engine mount comprising a rubber mount disposed between the hydraulic actuator and the vehicle body. 2. The cylinder is formed such that a center line of the piston or the cylinder protrudes in a direction of an extension line extending toward the rubber mount, and the rubber mount is provided on both sides of the extension line. The cylinder according to claim 1, further comprising at least one pair of mounting rubbers arranged, wherein mounting surfaces of the mounting rubber and the cylinder are inclined inwardly with respect to a direction in which the extension line extends. Engine mount.