BACKGROUND OF THE INVENTION 1. Field of the Invention

[0001] The invention relates to a vehicle power source supporting structure. 2. Description of Related Art

[0002] Japanese Patent Application Publication No. 2007-137421 (JP 2007-137421 A) describes a vehicle power source supporting structure that is used to support a power source of a vehicle on a vehicle body via a plurality of elastic mount members. In this related art, at least one of the plurality of mount members is mounted, in a position lower than the height of the gravitational center of the power source, to a sub-frame that is elastically supported by the vehicle body (see JP 2007-137421 A).

[0003] Japanese Patent Application Publication No. 9-226386 (JP 9-226386 A) describes an engine support device formed by an engine mounting frame that is antivibrationally supported by a vehicle body, and an engine mount that has a stopper that limits roll of the engine. In this related art, noise in the vehicle cabin is suppressed, therefore improving comfort in the cabin space, by setting a minimum distance from an engine roll center to the center of the front side engine mount and roll stopper clearance of the front side engine mount as conditions beforehand in a static state (see JP 9-226386 A).

[0004] Here, when the power source rocks laterally due to centrifugal force when the vehicle turns, maneuvering stability may be lost. Therefore, there is room for improvement in this respect. ,

SUMMARY OF THE INVENTION

[0005] The invention thus provides a vehicle power source supporting structure that is capable of improving maneuvering stability when the vehicle turns.

[0006] A first aspect of the invention relates to a vehicle power source supporting structure. This vehicle power source supporting structure includes a plurality of mount portions that support a power source. An elastic center of the plurality of mount portions that support the power source is set to a position farther toward a vehicle longitudinal direction rear side than a gravitational center of the power source in a plan view.

[0007] In the aspect described above, the elastic center of the plurality of mount portions that support the power source is set to a position farther toward a vehicle longitudinal direction rear side than a gravitational center of the power source in a plan view. Therefore, the direction of moment from centrifugal force applied to the power source when the vehicle turns acts in a direction that follows the movement of the vehicle. Therefore, maneuvering stability when the vehicle turns improves.

[0008] In the aspect described above, the plurality of mount portions may be provided in at least two locations, one on a front side and one on a rear side in the vehicle longitudinal direction, in a housing compartment within which the power source is housed. An elastic modulus of the mount portion on the rear side and the mount portion on the front side may be set such that the elastic center of the plurality of mount portions is positioned farther toward the vehicle longitudinal direction rear side than the gravitational center of the power source.

[0009] In the aspect described above, maneuvering stability when the vehicle turns is improved by setting the elastic modulus of the mount portion on the rear side and the mount portion on the front side such that the elastic center of the plurality of mount portions is positioned farther toward the vehicle longitudinal direction rear side than the gravitational center of the power source.

[0010] In the aspect described above, the plurality of mount portions may be provided in at least two locations, one on a right side and one on a left side in a vehicle width direction, in a housing compartment within which the power source is housed. Also, support positions where the mount portion on the right side and the mount portion on the left side support the power source may be set farther toward the vehicle longitudinal direction rear side than the gravitational center of the power source.

[0011] According to this aspect, the elastic center of the plurality of mount portions is farther toward the vehicle longitudinal direction rear side than the gravitational center of the power source, such that maneuvering stability when the vehicle turns is improved, by setting the support positions of the mount portion on the right side and the mount portion on the left side farther toward the vehicle longitudinal direction rear side than the gravitational center of the power source.

[0012] In the aspect described above, the plurality of mount portions may be provided in at least two locations, one on a right side and one on a left side in a vehicle width direction, in a housing compartment within which the power source is housed. Also, support positions where the mount portion on the right side and the mount portion on the left side support the power source may be set farther toward a vehicle upper side than the gravitational center of the power source.

[0013] In the aspect described above, movement of the power source in the vehicle width direction when the vehicle turns is reduced, such that maneuvering stability when the vehicle turns improves, by setting the support positions of the mount portion on the right side and the mount portion on the left side farther toward the vehicle upper side than the gravitational center of the power source.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:

FIG. 1 is a perspective view of a front portion of a vehicle to which a power source supporting structure according to one example embodiment of the invention has been applied;

FIG 2 is a plan view of the front portion of the vehicle shown in FIG. 1;

FIG 3 is a front view of the front portion of the vehicle shown in FIG. 1;

FIG. 4 is a sectional view showing a frame format of a cross-section of a rear side mount portion according to the example embodiment of the invention, taken along a vehicle longitudinal direction; FIG 5 is a front view showing a frame format of the rear side mount portion according to the example embodiment of the invention;

FIG. 6 is a sectional view showing a frame format of a cross-section of a front side mount portion according to the example embodiment of the invention, taken along a vehicle width direction;

FIG 7 is a plan view illustrating the moment direction of the engine when the vehicle shown in FIG 1 turns to the right, and the direction of force acting on the vehicle at that time;

FIG 8 is a front view illustrating the amount of rocking of the engine in the vehicle width direction when the vehicle shown in FIG 1 turns; and

FIG 9 is a graph showing the relationship between inertance and rigid body resonance frequency of the engine in the vehicle width direction when turning. DETAILED DESCRIPTION OF EMBODIMENTS

[0015] A vehicle power source supporting structure according to one example embodiment of the invention will now be described with reference to FIGS. 1 to 8. A vehicle longitudinal direction front side will be indicated by arrow FR, a vehicle width direction outside will be indicated by arrow OUT, and a vehicle up-down direction upper side will be indicated by arrow UP. Also, the directions to the left and right in the vehicle width direction (i.e., the left and right sides) are lateral directions when facing the vehicle front side (i.e., the advancing side), with the direction to the right (i.e., the right side) being indicated by arrow RH and the direction to the left (i.e., the left side) being indicated by arrow LH.

[0016] As shown in FIG. 1, an engine compartment 14 as one example of a housing compartment within which an engine (power unit) 12 that is one example of a power source is housed, is provided in a front portion of a vehicle 10 to which the power source supporting structure of this example embodiment is applied (see also FIG 7). The engine 12 is coupled to a transmission, not shown, at one end of a crankshaft, also not shown, provided in the vehicle width direction. [0017] A front side member 18 that extends in the vehicle longitudinal direction is provided on both side portions in the vehicle width direction of the front portion of the vehicle 10. Also, an apron upper member 20 is arranged to the vehicle upper side and the vehicle width direction outside of the front side member 18. A rear end portion of the apron upper member 20 is joined to a front pillar, not shown.

[0018] As shown in FIGS. 1 to 3, a suspension tower 22 that supports an upper end portion of a suspension, not shown, extends between the apron upper member 20 and the front side member 18. The suspension tower 22 is joined to the front side member 18 and the apron upper member 20.

[0019] An antivibration sub-frame 24 that is generally ladder-shaped when viewed from above (see FIG 1) is provided on the lower side of the front side member 18. The antivibration sub-frame 24 extends between the left and right front side members 18 and is joined to them.

[0020] The antivibration sub-frame 24 includes a pair, of left and right arm support portions 26 that extend in the vehicle longitudinal direction and support suspension arms, not shown, a front frame portion 28 that connects front end portions of the pair of arm support portions 26 together in the vehicle width direction, and a rear frame portion 33 that connects rear end sides of the pair of arm support portions 26 together in the vehicle width direction (see FIGS. 1 and 2). Also, a front end side of each arm support portion 26 is joined to a front end side of the corresponding front side member 18, and a rear end side of each arm support portion 26 is joined to a rear end side of the corresponding front side member 18.

[0021] A front side mount portion 50 is provided on a substantially center portion of the front frame portion 28 in the vehicle width direction that forms the antiyibration sub-frame 24, and a rear mount portion 60 is provided on a substantially center portion of the rear frame portion 33 in the vehicle width direction that forms the antivibration sub-frame 24 (see FIGS. 1 and 2). Furthermore, a right side mount portion 30 is provided on the front side member 18 that is arranged on the vehicle width direction right side, and a left side mount portion 32 is provided on the front side member 18 that is arranged on the vehicle width direction left side.

[0022] In this way, in the engine compartment 14, the front side mount portion 50 is provided on the front side in the vehicle longitudinal direction, the rear mount portion 60 is provided on the rear side in the vehicle longitudinal direction, the right side mount portion 30 is provided on the right side in the vehicle width direction, and the left side mount portion 32 is provided on the left side in the vehicle width direction (see also FIG. 7). The engine 12 (FIG. 1) is supported by the front side mount portion 50 and the rear mount portion 60 (see FIGS. 1 and 2), and the right side mount portion 30 and the left side mount portion 32 (see also FIG. 7), which are provided at the front, rear, left, and right in the engine compartment 14.

[0023] The front side mount portion 50 and the rear mount portion 60 are both main weight sharing mounts that serve mainly to share the weight of the engine 12 (see FIG. 1). Therefore, the right side mount portion 30 and the left side mount portion 32 are non-weight sharing mounts. Also, the right side mount portion 30 and the front side mount portion 50 are formed by liquid-filled mounts.

[0024] As shown in FIGS. 1 and 2, a rear side mount bracket 70 is provided on the rear mount portion 60, and a rear end portion of the engine 12 (see FIG. 1) is mounted to this rear side mount bracket 70. The rear side mount bracket 70 has a fixed portion 72 that is generally rectangular-shaped when viewed from the front, and a pair of generally rectangular side wall portions 74 that extend toward the vehicle longitudinal direction rear side from both end portions of the fixed portion 72 in the vehicle width direction (see also FIG 5).

[0025] As shown in FIGS. 2 and 4, the rear mount portion 60 has an annular portion 62 formed in an annular shape with the vehicle width direction being the axial direction in a vehicle side view, and a flange 64 integrally provided with the annular portion 62. A rear side elastic member 68 formed by an elastic body of rubber or the like is provided inside the annular portion 62, as shown in FIG. 4. Also, the annular portion 62 is arranged between the side, wall portions 74 of the rear side mount bracket 70, as shown in FIGS. 2 and 5. [0026] The rear side mount bracket 70 is mounted to the rear mount portion 60 via a shaft 66 provided in an axial center portion of the annular portion 62, as shown in FIGS. 4 and 5. Also, side stoppers 76 formed by an elastic body of rubber or the like is provided between the side wall portions 74 of the rear side mount bracket 70 and the rear mount portion 60, as shown in FIG 5. The side stoppers 76 may be members that are formed separate from the rear mount portion 60, or they may be integrally formed with the rear side elastic member 68 of the rear mount portion 60.

[0027] As shown in FIG. 6, a first mounting member 52 that is mounted on the engine 12 side (see FIG 1), a second mounting member 54 that is mounted on the antivibration sub-frame 24 side (see FIG. 1), and a front side elastic member 56 that connects the first mounting member 52 and the second mounting member 54 together, are provided inside an upper end portion of the front side mount portion 50. Also, the front side elastic member 56 has a structure in which a lower portion 58 extends out downward at an angle.

[0028] As described above, the engine 12 is supported by the front side mount portion 50, the rear mount portion 60, the right side mount portion 30, and the left side mount portion 32. Also, as shown in FIGS. 1 and 2, an elastic center GD of the front side mount portion 50, the rear mount portion 60, the right side mount portion 30, and the left side mount portion 32 when viewed from above is set to a position that is farther toward the vehicle longitudinal direction rear side than the gravitational center GP of the engine 12 (see also FIG 7).

[0029] The elastic center GD is able to be positioned farther toward the rear side than the gravitational center GP by adjusting (setting) the elastic modulus of the front side mount portion 50 and the rear mount portion 60. In this example embodiment, the elastic center GD is positioned farther toward the vehicle longitudinal direction rear side than the gravitational center GP of the engine 12 by adjusting (setting) the elastic modulus of the rear mount portion 60. More specifically, by setting the width (thickness) in the vehicle width direction of the rear side elastic member 68 of the rear mount portion 60 shown in FIG. 4 wider (thicker), the elastic modulus in the vehicle width direction is increased (i.e., the elastic force in the vehicle width direction displayed by the rear mount portion 60 when the vehicle turns increases), which moves the elastic center GD farther toward the vehicle . longitudinal direction rear than the gravitational center GP.

[0030] Also, the elastic center GD is set to a position farther on the vehicle up-down direction upper side than the gravitational center GP of the engine 12, as shown by FIGS, l and 2.

[0031] Also, a support positions where the right side mount portion 30 and the left side mount portion 32 support both end portions of the engine 12 in the vehicle width direction are set farther toward the vehicle up-down direction upper side than the gravitational center GP of the engine 12, as shown in FIGS. 3 and 8.

<Operation and effects>

[0032] Next, the operation and effects of the example embodiment will be described.

[0033] First, a case in which the vehicle 10 turns to the right (i.e., the vehicle width direction right side, the right side in the advancing direction) will be described as an example. As shown in FIG. 7, when a steering wheel 42 is turned to the right indicated by arrow Kl , front wheels 40 turn to the right such that the vehicle 10 turns to the right as indicated by arrow K2.

[0034] As described above, the elastic center GD of the front side mount portion 50, the rear mount portion 60, the right side mount portion 30, and the left side mount portion 32 is set to a position farther toward the vehicle longitudinal direction rear side than the gravitational center GP of the engine 12 (see also FIGS. 1 and 2). Accordingly, the direction of moment from centrifugal force applied the engine 12 when the vehicle 10 turns to the right is the left direction such as that shown by arrow K3. That is, the direction (arrow K3) of the moment of the engine 12 is opposite the direction toward the right which is the turning direction (arrow K2) (i.e., opposite the operating direction of the steering wheel 42 (arrow Kl)).

[0035] Meanwhile, force stored in this case acts on the vehicle 10, so the vehicle 10 turns to the right (arrow K2) after a delay with respect to the operation of the steering wheel 42 (arrow Kl). Therefore, force toward the vehicle width direction left side indicated by arrow K4 acts on the vehicle 10. That is, force applied to the engine 12 works in the opposite direction of the direction toward the right which is the turning direction (arrow K2) (i.e., opposite the operating direction of the steering wheel 42 (arrow Kl )).

[0036] Therefore, when the vehicle 10 turns to the right, the moment direction of the engine 12 (arrow K3) and the direction of force applied to the vehicle 10 (arrow K4) are both the same direction toward the left. Similarly, when the vehicle 10 turns to the left, the moment direction of the engine 12 and the direction of force applied to the vehicle 10 are both the same direction toward the right. That is, the moment direction of the engine 12 (arrow K3) and the direction of force applied to the vehicle 10 (arrow K4) when the vehicle 10 turns are both the same direction.

[0037] By setting the elastic center GD of the front side mount portion 50, the rear mount portion 60, the right side mount portion 30, and the left side mount portion 32 to a position farther toward the vehicle longitudinal direction rear side than the gravitational center GP of the engine 12 is in this way, moment from the centrifugal force applied to the engine 12 when the vehicle 10 turns acts in the direction following the movement of the vehicle 10, so the vehicle 10 and the engine 12 behave as one, thus improving maneuvering stability when the vehicle 10 turns.

[0038] Also, the position of the elastic center GD is able to be easily positioned farther toward the vehicle longitudinal direction rear side than the gravitational center GP is, by adjusting (setting) the elastic modulus of the front side mount portion 50 and the rear mount portion 60. In this example embodiment, the elastic modulus in the vehicle width direction is increased and the elastic center GD is moved farther toward the vehicle longitudinal direction rear side than the gravitational center GP, by widening the width of the rear side elastic member 68 of the rear mount portion 60 in the vehicle width direction.

[0039] Also, as shown in FIG. 8, the support positions of the right side mount portion 30 and the left side mount portion 32 are set farther toward the vehicle upper side than the gravitational center GP of the engine 12 (see also FIGS. 1 and 3). Therefore, a movement Ml of the engine 12 in the vehicle width direction when the vehicle 10 turns is smaller than a movement M2 of a comparative example in which support positions of a right side mount portion 130 and a left side mount portion 132 indicated by virtual lines (chain double dash lines) are set farther toward the vehicle lower side than the gravitational center GP. As a result, the support rigidity of the engine 12 in the vehicle width direction is able to be increased, so maneuvering stability improves.

[0040] More specifically, as shown in FIG 9, when the support rigidity is increased, a rigid body resonance SI of the engine 12 in the vehicle width direction (see FIGS. 1 and 7) shifts to the high frequency side, away from a high frequency side S2 of a normal frequency range (an input frequency from a steering wheel 42 (see FIG. 7) maneuver) S3. Therefore, the effect of the rigid body resonance SI of the engine 12 in the vehicle width direction is reduced, i.e., the effect of inertia force of the engine 12 in the vehicle width direction due to resonance is reduced, so maneuvering stability improves.

[0041] Also, by supporting the front side mount portion 50 and the rear mount portion 60, which are the main weight sharing mounts that serve to mainly share the weight of the engine 12 (see FIG 1), with the antivibration sub-frame 24, vibration of the engine 12 in the vehicle up-down direction is damped, so the ride is more comfortable for the occupants.

[0042] In addition, the ride is made even more comfortable to the occupants by using liquid-filled mounts that have high damping performance for the right side mount portion 30 and the front side mount portion 50.

<Other methods of adjusting the position of the elastic center GD>

[0043] In this example embodiment, the elastic center GD is shifted (positioned) farther toward the vehicle longitudinal direction rear side than the gravitational center GP by increasing the elastic modulus in the vehicle width direction by widening the width of the rear side elastic member 68 of the rear mount portion 60 in the vehicle width direction, but it is not limited to this.

[0044] The elastic center GD may also be shifted (positioned) farther toward the vehicle longitudinal direction rear side than the gravitational center GP by increasing the elastic modulus in the vehicle width direction by widening the width of the side stoppers 76 formed by elastic bodies of rubber or the like of the rear mount portion 60 in the vehicle width direction shown in FIG. 5.

[0045] Also, the elastic center GD may be shifted (positioned) farther toward the vehicle longitudinal direction rear side than the gravitational center GP by increasing the elastic modulus of the rear mount portion 60 by another method.

[0046] Alternatively, the elastic center GD may be shifted (positioned) farther toward the vehicle longitudinal direction rear side than the gravitational center GP by reducing the elastic modulus of the front side mount portion 50. For example, the elastic center GD may be shifted (positioned) farther toward the vehicle longitudinal direction rear side than the gravitational center GP by reducing the elastic modulus of the front side mount portion 50 by making the thickness of the lower portion 58 of the front side elastic member 56 shown in FIG. 6 thinner.

[0047] Also, at least one of the front side mount portion 50 and the rear mount portion 60 may be control-mounted such that the elastic modulus is able to be electrically controlled (e.g., mounted using a magnetic fluid in which the viscosity changes according to the magnetic field), and the elastic center GD may be controlled so that it is positioned farther toward the vehicle longitudinal direction rear side than the gravitational center GP.

[0048] That is, the elastic center GD need only be set so that it is positioned farther toward the vehicle longitudinal direction rear side than the gravitational center GP, by adjusting the elastic modulus of the front side mount portion 50 and the elastic modulus of the rear mount portion 60.

[0049] Alternatively, the elastic center GD may be positioned (shifted) to farther the vehicle longitudinal direction rear side than the gravitational center GP, by inclining the front side mount portion 50 and the rear mount portion 60 toward the vehicle rear side of the gravitational center GP in a vehicle side view.

[0050] Alternatively, the elastic center GD may be shifted (positioned) farther toward the vehicle longitudinal direction rear side than the gravitational center GP by setting the support positions where the engine 12 is supported to positions farther toward the vehicle longitudinal direction rear side than the gravitational center GP of the engine 12, like a right side mount portion 30A and a left side mount portion 32A shown by the virtual lines (chain double dash lines) in FIG 7.

[0051] Moreover, a plurality of methods by which the position of the elastic center GD is adjusted may be suitably combined. That is, the elastic center GD of the front side mount portion 50, the rear mount portion 60, the right side mount portion 30, and the left side mount portion 32 need only be positioned farther toward the vehicle longitudinal direction rear side than the gravitational center GP of the engine 12.

<Other>

[0052] The invention is not limited to the example embodiment described above.

[0053] In the example embodiment described above, the right side mount portion 30 is provided on the vehicle width direction right side in the front portion of the vehicle 10, the left side mount portion 32 is provided on the vehicle width direction left side in the front portion of the vehicle 10, the front side mount portion 50 is provided on the vehicle longitudinal direction front side in the front portion of the vehicle 10, and the rear mount portion 60 is provided on the rear side in the vehicle longitudinal direction in the front portion of the vehicle 10. That is, mount portions that support the engine are -provided in four locations, i.e., front, rear, left, and right, in the front portion of the vehicle 10, but the mount portions are not limited to this. That is, mount portions that support the engine may also be provided in locations other than these four locations.

[0054] Furthermore, it goes without saying that the invention may be carried out in any one of a variety of modes within the scope of the invention.