JP2002349632A - Engine mounting device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To suppress frame resonance of a subframe on which an engine mount is arranged or a body of a vehicle body, thereby suppressing a muffled sound generated in a vehicle interior. SOLUTION: A sub frame 6 is provided on a side member of a vehicle body.
, And an engine mount 16 is disposed on the left frame member 9 of the sub-frame 6 at a position crossing the inertia main shaft 15 of the power unit 5, and a fluid engine mount 17 is provided on the other right frame member 10 at a position sandwiching the inertia main shaft 15. And an engine mount 18. The engine mounts 16 and 18 are set so that the transmission phase is the same with respect to the vibration input from the power unit 5 regardless of the frequency.
Numeral 7 is set so that the peak of the phase characteristic becomes the bounce resonance frequency f _B of the sub-frame 6, and the transmission phase becomes opposite to the vibration input from the power unit 5 in this bounce resonance frequency range. ing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffled sound in a vehicle interior by adjusting a fluid resonance characteristic of an engine mount when a fluid engine mount for supporting a horizontal engine is formed on a vehicle body or a subframe supported by the vehicle body. The present invention relates to an engine mount device capable of reducing the engine load.

[0002]

2. Description of the Related Art Conventional engine mounting devices include:
For example, JP-A-9-123770 (hereinafter, referred to as a first conventional example) and JP-A-9-240291 (hereinafter, referred to as a first conventional example)
(Referred to as a second conventional example) is known. In a first conventional example, an engine and a transmission are mounted on an engine and a transmission mounted on the engine in a state where the mount is interposed between vehicle bodies when the engine and a transmission mounted on the engine are mounted horizontally. An engine mounting system is described in which a plane including a principal axis of inertia and a vertical line passing through the center of gravity of the vehicle is formed, three or more mounting parts are provided, and all the mounting parts are located at least in the vicinity of the plane. .

The second conventional example has a sub-side member on a girder supporting a power train, and a curved portion for facilitating bending is formed on the right and left sub-side members constituting the sub-side member. First and second engine mounts for supporting the weight of the power train are mounted on these curved portions, and a third engine for releasing the power train when a predetermined load or more acts on the upper side of the power train in a vertical direction. A powertrain support device for mounting a mount is described.

[0004]

However, the first prior art has a structure in which the engine mount is vertically arranged with the engine inertia main shaft interposed therebetween, so that combustion in the direction of the engine roll, which is idle vibration, occurs. As for the excitation force, the engine mount that sandwiches the engine inertia main shaft has an opposite phase input and is canceled because the distance between the upper and lower points is short, but the excitation force in the vertical direction, which is the engine inertia excitation force during traveling, is There is an unsolved problem that a muffled sound is input from both upper and lower engine mounts to the vehicle body and is generated by a so-called engine inertia exciting force.

Further, in the second conventional example, an engine mount is arranged on a sub-frame to obtain a crushable zone where the engine falls during a collision, and the sub-frame is bent at the time of a collision to move the engine downward. Although it is configured to obtain a further crushable zone, the vertical vibration of the engine induces sub-frame resonance such as bounce of the sub-frame, generates a muffled sound in the cabin, and gives discomfort to the occupant There is an unsolved problem.

The present invention has been made in view of the above-mentioned unresolved problems of the prior art, and suppresses frame resonance of a subframe or a vehicle body on which an engine mount is arranged, thereby generating a vehicle interior. It is an object of the present invention to provide an engine mount device capable of suppressing a muffled sound.

[0007]

According to a first aspect of the present invention, there is provided an engine mounting apparatus for a vehicle equipped with a horizontal engine, the engine mounting apparatus comprising: a main engine inertia shaft on a subframe supported by a vehicle body; Each of the front and rear engine mounts is disposed at a front and rear position, and one of the front and rear engine mounts is constituted by a fluid engine mount having a phase maximum change frequency adjusted to a bounce resonance frequency range of the subframe.

According to a second aspect of the present invention, there is provided an engine mount device for a vehicle equipped with a laterally mounted engine, wherein the respective fluid engine mounts are disposed on a sub-frame supported by the vehicle body at front and rear positions sandwiching an engine inertia main shaft. And the phase maximum change frequency of one fluid engine mount is adjusted to the bounce resonance frequency range of the subframe, and the phase maximum change frequency of the other fluid engine mount is adjusted to the roll resonance frequency range of the subframe. It is characterized by doing.

Further, in the engine mount device according to a third aspect of the present invention, in the engine mount device for a vehicle equipped with a laterally mounted engine, the engine mounts are respectively disposed at front and rear positions on the vehicle body supporting the engine with respect to the engine inertia main shaft. It is characterized in that one of the engine mounts is constituted by a fluid mount in which the phase maximum change frequency is adjusted to a resonance frequency range of a vehicle body which causes a muffled sound in a vehicle cabin.

According to a fourth aspect of the present invention, there is provided an engine mount device for a vehicle equipped with a laterally mounted engine, wherein the fluid engine mounts are respectively disposed at front and rear positions on the vehicle body supporting the engine so as to sandwich the engine inertia main shaft. The phase maximum change frequency of one of the fluid engine mounts is adjusted to one frequency range of the resonance frequency of the vehicle body that causes the muffled sound in the vehicle interior, and the phase maximum change frequency of the other fluid engine mount is adjusted to the interior of the vehicle interior. It is characterized in that the frequency is adjusted to a different frequency range from the resonance frequency of the vehicle body that causes a muffled sound.

[0011]

According to the engine mount device of the present invention, one of the engine mounts respectively disposed at the front and rear positions of the sub-frame sandwiching the engine inertia main shaft has one of the phase maximum change frequency and the bounce resonance frequency range of the sub-frame. The engine mount is located at a relatively close position because the vibration input from the engine to the engine mount and the fluid engine mount sandwiching the main engine inertia shaft when the engine is idling is in opposite phase. When the vibration input of the opposite phase is canceled each other, and the engine vibration becomes the inertial excitation force area during running and the sub-frame is in a bounce state, the transmission phase of the fluid engine mount becomes the transmission phase of the other engine mount. Sub-frame bounce resonance due to reverse phase Excited hardly, there is an advantage that it is possible to suppress occurrence of muffled sound.

Further, according to the engine mount device of the present invention, the phase maximum change frequency of one of the fluid engine mounts respectively disposed at the front and rear positions of the sub-frame across the engine inertia main shaft is set to the bounce resonance frequency range of the sub-frame. And the other phase maximum change frequency is adjusted to the roll resonance frequency range of the subframe. In addition to the effect of the invention according to claim 1, the bounce resonance frequency is exceeded and the roll resonance frequency range is reached. Then, while the transmission phase of one fluid engine mount returns to the same phase as the engine input, the transmission phase of the other fluid engine mount becomes the opposite phase to the engine input. When exceeding the frequency range and reaching the pitching resonance frequency range, both fluid engine mounts By the phase, less likely to excite the pitch resonance, bounce resonance frequency range, there is an advantage that it is possible to reduce the occurrence of each cabin booming noise in the roll resonance frequency band and the pitch resonant frequency range.

Further, according to the engine mount device of the present invention, one of the engine mounts disposed at the front and rear positions of the vehicle body supporting the engine at the front and rear sides of the engine inertia main shaft is used to determine the phase maximum change frequency and the muffled sound in the vehicle interior. , The phase maximum change frequency of the fluid engine mount is adjusted to any of the resonance frequencies of the vehicle body, which causes the muffled sound in the vehicle cabin. As a result, the excitation input from the engine is in the opposite phase, so that the effect of suppressing body resonance and reducing muffled sound is obtained.

Further, according to the engine mount device of the present invention, the phase maximum change frequency of one of the fluid engine mounts respectively disposed at the front and rear positions sandwiching the engine inertia main shaft of the vehicle body is a factor of the booming noise in the vehicle interior. And the maximum phase change frequency of the other fluid engine mount is adjusted to another resonance frequency range of the vehicle body. Since the excitation input is in the opposite phase, the effect of suppressing both resonance and reducing muffled sound is obtained.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic side view showing a first embodiment of the present invention. In the drawing, reference numeral 1 denotes a vehicle body of a front-wheel drive type automobile in which an engine is placed laterally, and a side member 2 is disposed below the vehicle body 1. A subframe 6 on which a power unit 5 including the engine 3 and the transmission 4 is mounted is supported at a position corresponding to the engine room of the side member 2.

As shown schematically in FIGS. 2 and 3, the sub-frame 6 includes a front frame member 7 and a rear frame member 8 separated from the front frame member 7 by a predetermined distance.
The left frame member 9 and the right frame member 10 extending in the front-rear direction, which respectively connect the left and right ends of the front frame 7 and the rear frame member 8 individually, are formed in a cross-girder shape that easily generates a muffled sound.

The sub-frame 4 has front elastic members 11L and 11R attached to its four front corners, and rear elastic members 12L and 12R attached to its rear ends.
1L, 11R and rear elastic portions 12L, 12R are provided with mounting portions 13 and 1 formed on the side member 2 as shown in FIG.
By being attached to the side member 4, it is supported by the side member 2.

Further, as shown in FIG. 3, an engine mount 16 composed of a normal rubber bush or the like is disposed on the left frame member 9 constituting the sub-frame 6 at a position intersecting with the inertia main shaft 15 of the power unit 5. The right frame member 10 constituting the sub-frame 6 is provided with a fluid engine mount 17 capable of adjusting a transmission phase characteristic at a position close to the inertia main shaft 15 and an engine mount including a normal rubber bush or the like. 18 are provided. The left side of the transmission 4 is supported by the engine mount 16, and the right side of the engine 3 is supported by the fluid engine mount 17 and the engine mount 18, respectively. Further, torque is applied between the case body of the engine 3 and the rear frame member 8. A rod 19 is provided.

When the power unit 5 composed of the engine 3 and the transmission 4 is supported by the sub-frame 6, six rigid mode resonances occur in the sub-frame 6. Among them, the resonance which has the highest sensitivity to be input to the vehicle body and may cause discomfort to the occupant due to a muffled sound in the cabin is caused by the bounce that the sub-frame 6 shown in FIG. A resonance mode, a pitch resonance mode rotating around a pitch axis in the vehicle left-right direction shown in FIG. 4B and a roll resonance mode rotating around a roll axis in the vehicle front-rear direction shown in FIG. One.
In most cases, these resonance modes are arranged in the order of the bounce resonance mode, the roll resonance mode, and the pitch resonance mode from the lowest frequency.

Further, the vibration of the engine 3 generates a vibration exciting force at the time of idling and causes the engine 3 to rotate substantially around the inertial main shaft 15 described above. The inertial excitation force increases, and vertical vibrations mainly occur. Therefore, one of the engine mounts disposed on the right frame member 10 with the inertia main shaft 15 interposed therebetween is a fluid engine mount 17 composed of a fluid insulator having fluid resonance, and the transmission phase characteristic is large near the resonance. The phase is changed so that the output phase is opposite to the vibration input.

That is, the fluid engine mount 17 is
As shown in FIG. 5 (a), peak opposite phases side of the phase characteristics appear at the bounce resonance frequency f _B of the sub-frame 6, it is tuned to the same phase close to 0 ° at the other frequency range And the absolute spring characteristics
(B) tuning is performed to change from a low spring characteristic to a high spring characteristic at the bounce resonance frequency f _B ,
As shown in FIG. 5A, the other engine mount 18 has a phase characteristic set to a constant value close to substantially 0 ° regardless of the frequency, and also has an absolute spring characteristic as shown in FIG. 5B. The constant low spring characteristic is set regardless of the frequency.

Therefore, when the sub-frame 6 undergoes bounce resonance, the phase characteristic of the fluid engine mount 17 is on the opposite phase side, and the engine mount 18 maintains the same phase. Next, near the roll resonance of the sub-frame 6, the resonance has already passed in the fluid engine mount 17, and the phase characteristic returns to the same phase side. At a frequency sufficiently lower than the fluid resonance in the sub-frame bounce resonance, the fluid engine mount 17 and the engine mount 18 have substantially the same spring constant and phase characteristics, and even near the sub-frame roll resonance sufficiently higher than the fluid resonance, Although the phase characteristics of the fluid engine mount 17 and the engine mount 18 are substantially equal, the absolute spring characteristics of the fluid engine mount 17 are larger than those of the engine mount 18.

Next, the operation of the first embodiment will be described. Now, when the engine 3 is in an idling state, a vibration for rotating the engine 3 around the inertia main shaft 15 is generated by the combustion excitation force, and as shown in FIG.
The engine vibration inputs of opposite phases are provided to the fluid engine mounts 17 and 18. Oscillation frequency at this time is about 20～25Hz, since a frequency lower than the sub-frame bouncing resonance frequency f _B, the two fluid engine mounts 17 and 18 are the same phase transfer characteristic of, as shown in FIG. 6, the sub-frame Since forces in directions opposite to each other act on the fluid engine mounts 17 and 18 adjacent to each other, both are canceled and vibration of the subframe 6 is suppressed.

When the vehicle starts running from this idling state and starts running, the engine vibration input increases and the engine vibration input becomes the inertial excitation force region and becomes the same phase in the vertical direction. In the frame bounce resonance region, as shown in FIG. 7, the engine vibration inputs to the fluid engine mount 17 and the engine mount 18 have the same phase, but the transmission phase of the fluid engine mount 17 is in the opposite phase, and the engine mount 17 has the opposite phase. Are transmitted in the same phase to the sub-frame 6 via the fluid engine mounts 17 and 18, so that it is difficult to excite bounce resonance, and the bounce vibration of the sub-frame 6 is reduced. Can be suppressed.

Further, when the engine vibration is in the inertial excitation force region and the engine vibration is input in the same direction in the vertical direction, the vibration frequency thereof is higher than the bounce resonance frequency f _B and the roll resonance frequency f _B is higher.
_When it becomes near _R and becomes the subframe roll resonance region,
As shown in FIG. 8, although the engine vibration input inputted to the fluid engine mount 17 and the engine mount 18 are in phase, the fluid engine mount 17 is beyond the set bounce resonance frequency f _B, transmission phase Are closer to the same phase, the phase is advanced from the transmission phase of the engine mount 18.
And the engine mount 18, it becomes difficult to excite the roll resonance, and the roll vibration of the sub-frame 6 can be suppressed.

Furthermore, when the engine vibration is input in the same direction in the upward direction in the inertial excitation force region, the vibration frequency is higher than the roll resonance frequency f _R and the pitch resonance frequency f _R is higher than the roll resonance frequency f _{R.
Even in the} vicinity of _P and in the sub-frame pitch resonance region, as shown in FIG. 9, the engine vibration inputs to the fluid engine mount 17 and the engine mount 18 are in phase, and the fluid engine mount 17 and the engine mount Since the transmission phase of the motor 18 is maintained in the same phase, vibrations of the same phase are transmitted to the sub-frame 6 via the fluid engine mount 17 and the engine mount 18, so that it is difficult to excite pitch resonance.
Pitch vibration can be suppressed.

Here, when a kinetic force is applied to the engine by applying the finite element method, the transmission force transmitted from the suspension member to the vehicle body via the engine mount 16, the fluid engine mount 17, and the engine mount 18 is determined. By calculating the relationship between the transmission power to the vehicle body and the muffled sound at the driver's ear position from experimental values, the simulation result of the muffled sound obtained by multiplying the two is shown in FIG.
Shown in

As is apparent from the simulation results, in the first embodiment, as shown by the solid line, the transmission phase of one fluid engine mount 17 is set to the opposite phase in the sub-frame bounce mode, whereby the dotted line is drawn. It has been confirmed that the muffled sound in the bounce resonance frequency region can be significantly reduced as compared with the conventional example.

In the first embodiment, the case where the front engine mount is the fluid engine mount 17 having fluid resonance among the engine mounts sandwiching the inertia main shaft 15 with the right frame member 10 has been described. The invention is not limited to this, and the engine mount 18 behind the inertia main shaft 15 may be set as a fluid engine mount.

In the first embodiment, the case where two engine mounts are arranged on the right frame member 10 with the inertia main shaft 15 interposed therebetween has been described. However, the present invention is not limited to this. The engine mount may be arranged at a position intersecting with the inertia main shaft, two engine mounts may be arranged on the left frame member 9 with the inertia main shaft 15 interposed therebetween, and one of them may be constituted by a fluid engine mount, Further, both the left frame member 9 and the right frame member 10 use the inertia main shaft 1.
Alternatively, two engine mounts may be formed so as to sandwich 5 and one of them may be configured as a fluid engine mount.

Next, a second embodiment of the present invention will be described with reference to FIGS.
FIG. 16 will be described. In the second embodiment, both of the two engine mounts sandwiching the inertia main shaft 15 are fluid engine mounts, and their fluid resonance frequencies are different. That is, in the second embodiment, as shown in FIG. 11, the engine mount provided on the right frame member 10 of the sub-frame 6 in the first embodiment described above is replaced with a fluid engine mount 28.
As shown in FIG. 13A, the phase characteristic is tuned such that a peak on the opposite phase side appears at the roll resonance frequency f _R of the subframe 6 and has the same phase close to 0 ° in other frequency ranges. And the absolute spring characteristics
As shown in FIG. 3 (b), the configuration is the same as that of the above-described first embodiment except that the tuning is performed so as to change from the low spring characteristic to the high spring characteristic at the roll resonance frequency f _R. Parts corresponding to those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

In the second embodiment, subframe 6
When bounce resonance occurs, the phase characteristic of the fluid 17 is on the opposite phase side, and the fluid engine mount 28 has not yet reached the resonance frequency, so that there is no phase change in the transfer characteristic. Next, near the roll resonance of the sub-frame 6, the phase characteristic of the engine mount 28 is on the opposite phase side, but the engine mount 17 has already passed resonance,
The phase characteristics have returned to the same phase.

At a frequency sufficiently lower than the fluid resonance at the subframe bounce resonance, the spring constant and the phase characteristic are substantially equal, and even near the subframe pitch resonance sufficiently higher than the fluid resonance, both fluid engine mounts 17 and The resonance frequency of 28 has passed, and both the spring constant and the phase characteristic are substantially equal. The sub-frame bounce resonance has in-phase vibration at the positions of the fluid engine mount 17 and the fluid engine mount 28. The sub-frame roll resonance is a vibration mode in which a node is formed at a substantially central position in the left-right direction with the vehicle front-rear direction as an axis. Therefore, in-phase vibration occurs at the positions of the fluid engine mount 17 and the fluid engine mount. Since the resonance has a node between the fluid engine mounts 17 and 28 in the vehicle left-right axis, the fluid engine mount 17
And the position of the fluid engine mount 28 are in an opposite phase vibration mode.

Next, the operation of the second embodiment will be described. Now, when the engine 3 is in an idling state, a vibration for rotating the engine 3 around the inertia main shaft 15 is generated by the combustion excitation force, so that the fluid engine mounts 17 and 28 are moved as shown in FIG. Engine vibration inputs of opposite phases are provided. Oscillation frequency at this time is about 20～25Hz, since a frequency lower than the sub-frame bouncing resonance frequency f _B, the two fluid engine mounts 17 and 28 become the transfer characteristic of the phase, the fluid proximate to the sub-frame 6 Since forces in opposite directions act on the engine mounts 17 and 28,
Both are canceled, and the vibration of the sub-frame 6 is suppressed.

When the vehicle starts running from this idling state and starts running, the engine vibration input increases, and the engine vibration input becomes the inertial excitation force area and becomes the same phase in the vertical direction. In the frame bounce resonance region, as shown in FIG. 14, the engine vibration inputs to the fluid engine mounts 17 and 28 have the same phase, but the transmission phase of the fluid engine mount 17 is in the opposite phase, and Since the transmission phases are the same, vibrations of opposite phases are transmitted to the subframe 6 via the fluid engine mounts 17 and 28, so that it is difficult to excite bounce resonance, and the bounce vibration of the subframe 6 is suppressed. can do.

Further, when the engine vibration is in the inertial excitation force region and the engine vibration is input in the same phase in the vertical direction, the vibration frequency is higher than the bounce resonance frequency f _B and the roll resonance frequency f _B is higher.
_When it becomes near _R and becomes the subframe roll resonance region,
As shown in FIG. 15, the fluid engine mounts 17 and 2
While the engine vibration input inputted to 8 are in phase, the fluid engine mount 17 is beyond the bounce resonant frequency f _B, which is set, is transmitted phase to return to the same phase, but the transfer of fluid engine mounts 28 Since the phase is opposite, the fluid engine mount 17 is
Since the vibrations of opposite phases are transmitted via the and 28, it is difficult to excite the roll resonance, and the roll vibration of the sub-frame 6 can be suppressed.

Further, when the engine vibration is input in the same direction in the upward direction in the inertial excitation force region, the vibration frequency is higher than the roll resonance frequency f _R and the pitch resonance frequency f is higher than the roll resonance frequency f _R.
When it becomes near _P and becomes the subframe pitch resonance region,
As shown in FIG. 16, the fluid engine mounts 17 and 2
8, the engine vibration input is in the same phase, but the fluid engine mount 28 exceeds the set roll resonance frequency f _R , so that the transmission phase returns to the same phase, so that the two fluid engine mounts Since the transmission phases of 17 and 28 are the same, vibrations of the same phase are transmitted to the subframe 6 via the fluid engine mounts 17 and 28, so that it is difficult to excite pitch resonance,
Pitch vibration of the sub-frame 6 can be suppressed.

Here, the transmission force transmitted from the suspension member to the vehicle body via the engine mount 16 and the fluid engine mounts 17 and 28 when the exciting force is applied to the engine by applying the finite element method is calculated. FIG. 17 shows a simulation result of the muffled sound obtained by multiplying the relationship between the transmission force to the vehicle body and the muffled sound at the driver's seat ear position from experimental values.

As is apparent from the simulation results, in the second embodiment, as shown by the solid line, in the sub-frame bounce mode, the transmission phase of one of the fluid engine mounts 17 is set to the opposite phase, so that the dotted line is shown. Muffled sound in the bounce resonance frequency region can be greatly reduced as compared with the prior art, and even in the roll resonance mode, by setting the transmission phase of the other fluid engine mount 28 to the opposite phase, the roll resonance The muffled sound in the frequency domain can be reduced as compared with the conventional example.
It has been confirmed that by making the transmission phases of the phase Nos. 28 the same, the muffled sound in the pitch resonance frequency region can be reduced.

In the second embodiment, the positions of the fluid engine mounts 17 and 28 with respect to the inertia main shaft 15 can also be reversed, and the inertia main shaft 15 can be interposed between the left frame member 9 side. The two fluid engine mounts 17 and 28 are disposed at the right frame member 1.
Engine mount 1 at a position that intersects with the inertia main shaft 15
6 may be provided, and furthermore, both the left frame member 9 and the right frame member 10 have an inertia main shaft 15.
The fluid engine mount may be provided at two positions sandwiching the.

Next, a third embodiment of the present invention will be described with reference to FIGS.
FIG. 20 will be described. In the third embodiment, instead of supporting the power unit 5 with the sub-frame 6, an engine mount is arranged directly on the body frame to support the power unit 5. That is, in the third embodiment, as shown in FIGS. 18 and 19, front side members 32 and 33 extending in the front-rear direction at predetermined intervals at positions corresponding to the engine room of the body frame 31, and these front side members Member 3
Front cross members 34 and 35 connecting the front and rear ends of the front and rear members 2 and 33 are arranged in a cross-girder shape.
As shown in the figure, an engine mount 36 composed of a rubber bush or the like is disposed at a position intersecting with the inertia main shaft 15 of the power unit 5 of one of the front side members 32, and the inertia when viewed from the plane of the other front side member 33. The fluid engine mount 3 is located at the front and rear positions of the main shaft 15
7, 38 are provided.

Then, the transmission 4 is mounted on the engine mount 36.
Of the engine 3 is supported by the fluid engine mounts 37 and 38. The fluid engine mount 37 has a bent two-node or three-node body frame in which the peak on the opposite phase side of the phase characteristic occurs in a relatively low frequency region as shown by the solid line in FIG. It is tuned so that it appears at the elastic bending resonance frequency f _EB and has the same phase close to 0 ° in other frequency ranges, and the absolute spring characteristic is also at the elastic bending resonance frequency f _EB as shown by the solid line in FIG. Tuning is performed so as to change from the low spring characteristic to the high spring characteristic, and the other fluid engine mount 38 has a peak on the opposite phase side of the phase characteristic in FIG.
In FIG. 8 (a), as shown by the dotted line, it appears at the torsional resonance frequency f _T of the body frame higher than the elastic bending resonance frequency, and is tuned to have the same phase close to 0 ° in other frequency ranges, and has the absolute spring. The characteristics are also tuned so as to change from the low spring characteristic to the high spring characteristic at the torsional resonance frequency f _T as shown by the dotted line in FIG.

According to the third embodiment, the elastic bending resonance frequency f of two bending nodes or three bending nodes is provided on the body frame 31.
_{When the} vibration input in the area of the _EB is transmitted, the front side members 32 and 33 swing up and down as shown in FIG. 21, and the sub-frames in the first and second embodiments described above. The state is similar to that of the bounce resonance. In this state, similarly to the second embodiment, the transmission phase of the fluid engine mount 37 is opposite to the phase of the vibration input, and the transmission phase of the fluid engine mount 38 is in phase with the phase of the vibration input. Accordingly, it becomes difficult to excite the elastic bending resonance due to the vibration input from the power unit 5, and it is possible to suppress the occurrence of the muffled sound in the vehicle interior.

When a vibration input in the region of the torsional resonance frequency f _T is transmitted to the vehicle body frame 31, the front cross members 34, 35 are lowered to the right and to the left as viewed from the front, as shown in FIG. Is repeated, and a state similar to the roll resonance of the sub-frame in the first and second embodiments described above is obtained. In this state, similarly to the second embodiment, the fluid engine mount 37
Becomes higher than the elastic bending resonance frequency f _EB , the transmission phase returns to the same phase with respect to the phase of the vibration input, and the fluid engine mount 38 has an opposite phase to the phase of the vibration input instead. This makes it difficult to excite the torsional resonance due to the vibration input from the power unit 5, and it is possible to suppress the occurrence of the muffled sound in the vehicle interior.

In the third embodiment, the case where one engine mount 36 is disposed on the front side member 33 on the side of the transmission 4 at a position intersecting with the inertia main shaft has been described. However, the present invention is not limited to this. Instead, two engine mounts may be provided so as to sandwich the inertia main shaft, and these engine mounts may be constituted by fluid engine mounts.

In the third embodiment, the case where two engine mounts sandwiching the inertia main shaft on the engine 3 side are constituted by the fluid engine mounts 37 and 38 has been described. Similarly, even if only one of them is constituted by the fluid engine mount 37 and the other is constituted by an engine mount such as a normal rubber bush, the resilience in the elastic bending resonance region similar to that of the first embodiment described above. Sound can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a first embodiment of the present invention.

FIG. 2 is a schematic perspective view showing a subframe to which the present invention can be applied.

FIG. 3 is a plan view of FIG. 2;

4A and 4B are explanatory diagrams showing resonance modes of a subframe, wherein FIG. 4A shows a bounce resonance mode, FIG. 4B shows a pitch resonance mode, and FIG. 4C shows a roll resonance mode.

FIG. 5 is an explanatory diagram showing engine mount characteristics of the fluid engine mount in the first embodiment.

FIG. 6 is an explanatory diagram for explaining an operation during idle vibration according to the first embodiment;

FIG. 7 is an explanatory diagram for explaining an operation at the time of bounce resonance according to the first embodiment;

FIG. 8 is an explanatory diagram for explaining an operation at the time of roll resonance according to the first embodiment;

FIG. 9 is an explanatory diagram for explaining an operation at the time of pitch resonance of the first embodiment;

FIG. 10 is a characteristic diagram illustrating a simulation result of a relationship between a frequency and a muffled sound according to the first embodiment.

FIG. 11 is a schematic perspective view showing a second embodiment of the present invention.

FIG. 12 is a plan view of FIG. 11;

FIG. 13 is an explanatory diagram showing engine mount characteristics of the fluid engine mount in the second embodiment.

FIG. 14 is an explanatory diagram for explaining an operation at the time of bounce resonance according to the second embodiment;

FIG. 15 is an explanatory diagram for explaining an operation at the time of roll resonance according to the second embodiment;

FIG. 16 is an explanatory diagram for explaining an operation at the time of pitch resonance of the second embodiment;

FIG. 17 is a characteristic diagram illustrating a simulation result of a relationship between a frequency and a muffled sound according to the second embodiment.

FIG. 18 is a schematic perspective view showing a third embodiment of the present invention.

FIG. 19 is a plan view of the front side in FIG. 18;

FIG. 20 is an explanatory diagram showing engine mount characteristics of the fluid engine mount according to the third embodiment.

FIG. 21 is an explanatory diagram for describing an elastic bending resonance mode according to the third embodiment.

FIG. 22 is an explanatory diagram for explaining a torsional resonance mode according to the third embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 2 Side member 3 Engine 4 Transmission 5 Power unit 6 Subframe 15 Inertia spindle 16 Engine mount 17 Fluid engine mount 18 Engine mount 28 Fluid engine mount 31 Body frame 32, 33 Front side member 34, 35 Front cross member 36 Engine mount 37,38 Fluid engine mount

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazushi Murakami Nissan Motor Co., Ltd., 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture (72) Inventor Akihiko Hasegawa 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa F Terms (reference) 3D035 CA02 CA14 CA19 3J047 AA01 FA02 GA03 3J048 AA05 AC04 AD01 CB23 DA01 EA01

Claims (4)

[Claims] 1. An engine mount device for a vehicle with a horizontal engine, wherein engine mounts are respectively disposed at front and rear positions on a sub-frame supported by a vehicle body and sandwiching an engine inertia main shaft, and one of the front and rear engine mounts is phased. An engine mount device comprising a fluid engine mount whose maximum change frequency is adjusted to a bounce resonance frequency range of the subframe. 2. An engine mount device for a vehicle with a horizontal engine, wherein each of the fluid engine mounts is disposed on a sub-frame supported by the vehicle body at front and rear positions sandwiching an engine inertia main shaft. An engine mount device wherein a maximum change frequency is adjusted to a bounce resonance frequency region of the subframe, and a phase maximum change frequency of the other fluid engine mount is adjusted to a roll resonance frequency region of the subframe. 3. An engine mount apparatus for a vehicle equipped with a horizontal engine, wherein the engine mounts are respectively disposed at front and rear positions on a vehicle body supporting the engine so as to sandwich an engine inertia main shaft, and one of the front and rear engine mounts has a maximum phase change. An engine mount device comprising a fluid mount whose frequency is adjusted to a resonance frequency range of a vehicle body that causes a muffled sound in a vehicle interior. 4. An engine mount device for a vehicle with a horizontal engine mounted thereon, wherein a fluid engine mount is disposed on a vehicle body supporting the engine at front and rear positions sandwiching an engine inertia main shaft, respectively, and a phase maximum change frequency of one of the fluid engine mounts is provided. Is adjusted to one of the resonance frequencies of the vehicle body that causes the muffled sound in the vehicle interior, and the phase maximum change frequency of the other fluid engine mount is adjusted to the resonance frequency of the vehicle body that causes the muffled sound in the vehicle interior. An engine mount device characterized in that the frequency is adjusted to another frequency range within.