JP6131226B2 - Subframe fastening structure - Google Patents

Description

  The present invention relates to a subframe fastening structure for a vehicle.

  2. Description of the Related Art Conventionally, a rear suspension device is known in which a rear wheel is supported by a sub member such as a suspension member and a sub frame attached to a vehicle body frame via an elastic bush via an arm such as an upper arm and a lower arm (for example, Patent Documents). 1). This rear suspension device causes a displacement in the vertical direction of the suspension member when a lateral force acts on the rear wheel during turning, and increases the amount of change in geometry, thereby promoting compliance steer in the toe-in direction, and It is configured to improve maneuverability.

Japanese Utility Model Publication No. 2-12906

  By the way, in a vehicle having a subframe as a submember, for example, turning by lowering the subframe so that the mount height of the subframe (the height of the fastening portion of the subframe with respect to the vehicle body frame) approaches the height of the roll center. It is considered that the roll angle at the time can be reduced to improve the maneuverability. However, if it is attempted to improve the operability during turning by reducing the roll angle, it is necessary to secure clearance with peripheral parts (for example, a fuel tank) of the subframe. There is a problem that cannot be sufficiently reduced.

In view of this, a configuration is conceivable in which the subframe and the vehicle body frame having mounts at both ends in the front-rear direction of the vehicle are bent so as to protrude upward. According to this, the height of the fastening portion of the sub-frame with respect to the vehicle body frame can be lowered, and a clearance with the peripheral parts can be ensured. However, in the configuration in which the subframe and the vehicle body frame are bent, it is necessary to ensure (reinforce) the rigidity, which causes a new problem that the vehicle weight increases and the manufacturing cost of the vehicle also increases.
Therefore, there is a demand for a frame structure that can improve the maneuverability during turning with a simple configuration so that the manufacturing cost of the vehicle does not increase.

  The subject of this invention is providing the sub-frame fastening structure of the simple structure which is excellent in the operativity at the time of turning.

The present invention that has solved the above problems is a subframe fastening structure for fastening a subframe to which a suspension arm of a rear wheel of a vehicle is pivotally attached to a vehicle body frame of the vehicle, wherein the subframe is a front-rear direction of the vehicle. The vertical member is attached to the vehicle body frame by a front mount disposed at a front end portion of the vertical member and a rear mount disposed at a rear end portion of the vertical member. Each of the front mount and the rear mount is supported in a floating manner, and includes an inner cylinder portion fastened to the vehicle body frame side, an outer cylinder portion attached to the subframe side, the inner cylinder portion, and the outer cylinder portion. And the front mount and the rear mount are a fastening point of the inner cylinder portion to the vehicle body frame, and an elastic medium of the elastic body. Wherein the distance are different from each other and.
According to this subframe fastening structure, only the elastic centers of the front and rear mounts can be displaced downward independently of each other while maintaining the height of the fastening point of the mount with respect to the body frame of the inner cylinder portion. . That is, according to the subframe fastening structure of the present invention, the fastening point of the subframe to the vehicle body frame in the conventional technique is lowered by displacing only the elastic centers of the front mount and the rear mount downward independently of each other. The same effect as can be achieved. As a result, the subframe fastening structure of the present invention improves the operability while maintaining the height of the fastening point of the mount with respect to the body frame, that is, with a simple configuration without reinforcing the body frame or the like. be able to.

In such a subframe fastening structure, the left and right vertical members of the subframe are curved such that the rear end of the vertical member is higher than the front end, and the inner cylinder The distance between the fastening point to the body frame and the elastic center of the elastic body may be configured so that the rear mount is larger than the front mount.
According to this subframe fastening structure, the difference in height of the elastic center between the rear mount and the front mount can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the subframe fastening structure of the simple structure which is excellent in the operativity at the time of turning can be provided.

It is a perspective view of the vehicle body rear part structure containing the sub-frame fastening structure which concerns on embodiment of this invention. FIG. 2 is a bottom view showing a state where a sub-frame is removed from a vehicle body frame in the vehicle body rear structure shown in FIG. 1. It is a side view of the subframe fastening structure concerning the embodiment of the present invention. (A) is IVa-IVa sectional drawing of FIG. 3, (b) is IVb-IVb sectional drawing of FIG. It is operation | movement explanatory drawing of a vehicle provided with the sub-frame fastening structure which concerns on embodiment of this invention.

Hereinafter, a subframe fastening structure according to an embodiment of the present invention will be described.
FIG. 1 is a perspective view of a vehicle body rear structure 10 including a subframe fastening structure 1 according to an embodiment of the present invention. FIG. 2 is a bottom view showing a state where the sub-frame 3 is removed from the vehicle body frame 2.

  As shown in FIG. 1, the subframe fastening structure 1 of the present embodiment includes four mounts 4 (see FIG. 2) including an elastic body 7 (see FIGS. 4 (a) and (b)) described in detail later. The vehicle body frame 2 has a so-called floating support structure in which the subframe 3 is supported. 2 represents a front mount, and 4b represents a rear mount. However, when these are not particularly distinguished, they are simply referred to as a mount 4.

As will be described later, the sub-frame fastening structure 1 of the present embodiment includes four mounts 4 (see FIG. 2) in which the inner cylinder portion 6 (see FIGS. 4A and 4B) has a vertical height of the mount 4. The main feature is that it is higher than the vertical height of the elastic body 7 (see FIGS. 4A and 4B).
Below, after explaining the whole structure of the vehicle body rear part structure 10 including the subframe fastening structure 1, the subframe fastening structure 1 will be explained. Note that the front-rear, left-right, up-down directions in the present embodiment are based on the front-rear, left-right, up-down directions indicated by the arrows in FIG.

<Car body rear structure>
As shown in FIGS. 1 and 2, the vehicle body rear structure 10 according to the present embodiment includes a vehicle body frame 2 and a subframe 3 disposed on the lower side of the vehicle body frame 2.
The vehicle body frame 2 includes left and right rear side frames 11 and 11 and front and rear cross members 14 and 15 that are spanned between the rear side frames 11 and 11 and spaced apart from each other at a predetermined interval in the vehicle body longitudinal direction. It has.
Each of the left and right rear side frames 11, 11 maintains a straight shape in the front-rear direction of the vehicle above the subframe 3, as will be described later.

The front cross member 14 is longer in the vehicle width direction (left and right direction) than the center part of the left and right rear side frames 11 and 11 in the front-rear direction and arranged so as to be bridged between the rear side frames 11 and 11. It is a member. Both end portions 14a, 14a of the front cross member 14 are connected to the left and right rear side frames 11, 11, respectively.
Further, as shown in FIG. 1, the front cross member 14 is a member constituting a lower beam of the rear bulkhead 24. Incidentally, the rear bulkhead 24 is connected to the inside of the right wheel house 26 and is connected to the inside of the left wheel house (not shown for convenience of drawing).

As shown in FIGS. 1 and 2, the rear cross member 15 is a downwardly projecting arcuate member disposed behind the front cross member 14 so as to be bridged between the left and right rear side frames 11, 11.
Thereafter, both end portions 15a and 15a of the cross member 15 (the left end portion 15a is not shown in FIG. 1) are connected to the left and right rear side frames 11 and 11, respectively.
In FIG. 2, reference numerals 34 and 35 denote fastening portions to which a subframe 3 described below is fastened through the mount 4. Reference numeral 38 denotes a bolt for fastening the sub frame 3 to the vehicle body frame 2.

  As shown in FIG. 2, the subframe 3 includes left and right subside members 51, 51 formed in an arcuate shape in a plan view, and front and rear subcrosses spanned between the left and right subside members 51, 51. Members 52 and 53. These sub-side members 51 and 51 correspond to “vertical members” in the claims. Incidentally, each of the left and right sub-side members 51, 51 is arranged on the inner side in the vehicle width direction (left-right direction) so that the arched convex portions face each other.

As will be described later, the left and right sub-side members 51 and 51 are curved so that the rear end portion is higher than the front end portion in a side view.
Mounts 4 (front mounts 4a and 4a and rear mounts 4b and 4b), which will be described in detail later, are arranged at both front and rear ends of the left and right sub-side members 51 and 51.

  Each of the left and right rear suspensions 18 and 18 constitutes a multi-link double wishbone suspension having a suspension arm including an upper arm 18a, two lower arms 18b and 18b, and a control arm 18c. One end of each of the suspension arms 18a, 18b, 18c is pivotally attached to each of the left and right sub-side members 51, 51, and the other end thereof is pivotally attached to each of the left and right knuckles 54, 54.

<Subframe fastening structure>
Next, the subframe fastening structure 1 according to the present embodiment will be described.
FIG. 3 is a side view of the subframe fastening structure according to the present embodiment, and is a side view showing a state in which the subframe fastening structure is viewed in the direction of the arrow indicated by reference numeral III in FIG.
As shown in FIG. 3, in the subframe fastening structure 1 according to this embodiment, as described above, the subframe 3 is fastened to the vehicle body frame 2 via the front mount 4a and the rear mount 4b. .

  As described above, the sub-side member 51 of the sub-frame 3 is curved so that the rear end portion is higher than the front end portion in a side view. Specifically, the sub-side member 51 in a side view is curved so as to have a substantially S-shape extending. And each of the both ends of the subside member 51 is extended in the substantially horizontal direction.

Cylindrical mount holders 51 a are provided at both ends of the sub-side member 51. The mount holder 51a is fixed to each of both ends of the sub-side member 51 so that the central axis thereof is directed in the vertical direction.
As described below, the front mount 4a is attached to the front end mount holder 51a, and the rear mount 4b is attached to the rear end mount holder 51a.

  Incidentally, the rear side frame 11 of the vehicle body frame 2 to which the sub-side member 51 is fastened has a straight section S so as to maintain a straight shape in the front-rear direction of the vehicle above the sub-side member 51. .

4A to be referred to next is a sectional view taken along the line IVa-IVa in FIG. 3 showing a section of the rear mount 4b, and FIG. 4B is a sectional view taken along the line IVb-IVb in FIG. It is.
Here, after describing the rear mount 4b, the front mount 4a will be described.

As shown in FIG. 4A, the rear mount 4b has a substantially cylindrical shape having an insertion hole 6a for a bolt 38, and is arranged inside the cylindrical mount holder 51a.
The rear mount 4b includes an outer cylinder part 5, an inner cylinder part 6 arranged concentrically inside the outer cylinder part 5, and an outer cylinder part 5 and an inner cylinder part 6 arranged inside the outer cylinder part 5. And a cylindrical elastic body 7 that connects the two.

  A flange 5a is formed at the lower end of the outer cylinder portion 5 so as to extend to the outer diameter side. The flange 5a is positioned so that the outer cylinder portion 5 is disposed below the mount holder 51a by contacting the lower end of the mount holder 51a. The material of the outer cylinder portion 5 is not particularly limited as long as it has a predetermined mechanical strength, but usually a metal or the like can be suitably used.

The elastic body 7 in the present embodiment is set to have substantially the same height as the vertical height (length) of the outer cylinder portion 5. The elastic body 7 can be formed of an elastic material such as synthetic rubber.
The inner cylinder portion 6 is set so that its vertical height (length) is higher (longer) than the height of the outer cylinder portion 5 and the elastic body 7. The inner cylinder part 6 has a connection part 61 connected to the inner side of the outer cylinder part 5 via an elastic body 7 and an extension part 62 extending further upward from the connection part 61. . Incidentally, the vertical height (length) of the inner cylinder portion 6 in the rear mount 4b of this embodiment is set to about twice the vertical height (length) of the elastic body 7. In other words, the vertical height (length) of the connecting portion 61 of the inner cylinder portion 6 and the vertical height (length) of the extending portion 62 are set to be substantially the same.

The material of the inner cylinder part 6 is not particularly limited as long as it has a predetermined mechanical strength, but usually a metal or the like can be suitably used.
In FIG. 4A, reference numeral 8 denotes a stopper that is press-fitted into the upper opening of the mount holder 51a, and reference numeral 9 denotes a plate that contacts the lower end of the rear mount 4b. Incidentally, an insertion hole for the bolt 38 is formed at the center of the plate 9.

The rear mount 4b as described above is fastened to the fastening portion 35 of the rear side frame 11 with the bolt 38 as described above.
Specifically, as shown in FIG. 4A, an insertion hole 35 a for a bolt 38 is formed in the lower surface of the fastening portion 35 of the rear side frame 11, and a bolt 38 is formed in the hollow portion of the fastening portion 35. A nut 39 is disposed to be screwed together.

  The bolt 38 is inserted into the insertion hole 6 a of the inner cylinder portion 6 and the insertion hole 35 a of the fastening portion 35 through the plate 9 disposed at the lower end of the rear mount 4 b, and the tip of the bolt 38 is screwed into the nut 39. Thus, the sub-side member 51 (sub-frame 3) is connected to the rear side frame 11 (vehicle body frame 2) by the bolt 38 via the rear mount 4b that contacts the fastening portion 35 of the rear side frame 11 at the upper end of the inner cylinder portion 6. Will be concluded.

Next, the front mount 4a (see FIG. 3) will be described mainly with reference to FIG. 4 (b).
As described above, the front mount 4a is attached to the mount holder 51a provided at the front end of the sub-side member 51 (see FIG. 3).
The front mount 4a has an inner cylinder portion 6 (see FIG. 4B) that is lower (shorter) than the vertical height (length) of the inner cylinder portion 6 of the rear mount 4b (see FIG. 4A). Other than that, it is configured similarly to the rear mount 4b. As described above, the front mount 4a is fastened to the fastening portion 34 of the rear side frame 11 by the bolt 38. In FIG. 4B, reference numeral 34 a is an insertion hole for the bolt 38 formed in the fastening portion 34.

The vertical height (length) of the extending portion 62 of the inner cylinder portion 6 in the front mount 4a of the present embodiment is set to about half of the vertical height (length) of the connecting portion 61.
In FIG. 4B, reference numeral 5a denotes a flange of the outer cylinder part 5, reference numeral 6a denotes an insertion hole for the bolt 38 of the front mount 4a, reference numeral 7 denotes an elastic body, and reference numeral 8 Is a stopper, reference numeral 9 is a plate, and reference numeral 39 is a nut.

  4A and 4B, the elastic center C of the elastic body 7 in the front mount 4a and the rear mount 4b has a vertical height (length) on the axis of the elastic body 7. ). In the present embodiment, the intersection point between the contact surface 11a of the inner cylinder part 6 with respect to the rear side frame 11 (body frame 2) and the axis of the inner cylinder part 6 is defined as a fastening point P. Then, the distance between the fastening point P and the elastic center C of the elastic body 7 is different between the front mount 4a and the rear mount 4b.

  Specifically, the distance D1 (see FIG. 4A) between the fastening point P and the elastic center C in the rear mount 4b, and the distance D2 between the fastening point P and the elastic center C in the front mount 4a (FIG. 4 ( The relationship with b) is D1> D2.

Next, the effect of the sub-frame fastening structure 1 according to this embodiment will be described.
FIG. 5 is an operation explanatory view of the vehicle V provided with the sub-frame fastening structure 1 according to the present embodiment, and is a schematic view when the left-hand drive vehicle turns rightward as viewed from the rear of the vehicle V.
As shown in FIG. 5, in the subframe fastening structure 1 according to the present embodiment, the rear wheels T and T are supported by the subframe 3 via suspension arms (not shown), and the subframe 3 is mounted on the vehicle body by the mount 4. The frame 2 is supported floating. That is, the mount 4 exhibits a spring property based on the elastic body 7 (see FIGS. 4A and 4B) between the body frame 2 and the subframe 3.

  In the vehicle V provided with the sub-frame fastening structure 1 according to the present embodiment, when the vehicle V turns right by turning the handle H to the right, the rear wheels T and T have a turning center (not shown). Lateral forces Ft and Ft are generated. As a result, a moment M directed toward the turning center is generated in the roll center R. Based on this moment M, a downward component force Fd is generated at the elastic center of the left mount 4, and an upward component force Fu is generated at the right mount 4. As the component forces Fu and Fd increase, the roll angle of the vehicle V increases and the maneuverability during turning tends to deteriorate.

  By the way, the roll angle is reduced by lowering the subframe 3 so that the fastening height of the subframe 3 with respect to the vehicle body frame 2, that is, the fastening height H1 of the mount 4 with respect to the vehicle body frame 2, is brought close to the height H2 of the roll center R. Can be reduced.

  On the other hand, in the above-described conventional technology (see the column “Problems to be solved by the invention”), these peripheral components are used to secure clearance with peripheral components (for example, a fuel tank) of the subframe. On the other hand, it is necessary to bend the vehicle body frame and the like into a convex shape so that the vehicle body frame and the subframe do not interfere with each other. Therefore, in the conventional technology, it is necessary to ensure (reinforce) the rigidity of the body frame and the like, which increases the vehicle weight and the manufacturing cost of the vehicle.

  On the other hand, in the subframe fastening structure 1 according to the present embodiment, the inner cylinder portion 6 protrudes toward the vehicle body frame 2 from the outer cylinder portion 5 and the elastic body 7 (see FIGS. 4A and 4B). The elastic center of the mount 4 (the rear mount 4b in FIG. 4 (a) and the front mount 4a in FIG. 4 (b)) while maintaining the height of the fastening point P with respect to the body frame 2 of the inner cylinder portion 6). Only C (see FIGS. 4A and 4B) can be displaced downward.

  Thereby, the sub-frame fastening structure 1 can bring only the elastic center C of the mount 4 closer to the roll center R while maintaining the linearity of the body frame 2 (see the straight section S in FIG. 3). Therefore, according to the sub-frame fastening structure 1 according to the present embodiment, the vehicle body frame 2 or the like does not require reinforcement for securing rigidity, so that an increase in vehicle weight and manufacturing cost can be avoided, with a simple configuration, Stability during turning can be improved.

  Moreover, according to the sub-frame fastening structure 1 which concerns on this embodiment, NV performance can also be improved by using the elastic body 7 with a small spring constant. By the way, it is generally considered that a rigid or elastic body having a large spring constant is desirable when pursuing maneuverability, and NV performance and maneuverability are in a trade-off relationship. However, according to the present embodiment, since the operability is improved by shifting the elastic center C downward, this trade-off is eliminated.

  Further, according to the subframe fastening structure 1 according to the present embodiment, the position of the elastic center C of the mount 4 can be changed by changing the length of the extending portion 62 of the mount 4.

  Further, in the subframe fastening structure 1 according to the present embodiment, the distances (D1, D2) between the fastening point P of the inner cylinder portion 6 to the vehicle body frame 2 and the elastic center C of the elastic body 7 are different from each other. Can be set. According to such a subframe fastening structure 1, the position of the elastic center C in the front mount 4a and the position of the elastic center C in the rear mount 4b can be individually displaced in the vertical direction. Therefore, according to the subframe fastening structure 1, the degree of freedom in design when the roll angle is improved by the geometry is increased.

  In the subframe fastening structure 1 according to the present embodiment, the rear end of the subside member 51 (vertical member) of the subframe 3 is higher than the front end (see FIG. 3). On the other hand, the distance D1 (see FIG. 4A) between the fastening point P and the elastic center C in the rear mount 4b is the distance D2 between the fastening point P and the elastic center C in the front mount 4a (see FIG. 4B). ) (D1> D2), the difference in height of the elastic center C between the rear mount 4b and the front mount 4a can be reduced.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, It can implement with a various form.
In the embodiment, the vertical height (length) of the extending portion 62 of the inner cylinder portion 6 in the rear mount 4b and the vertical height (length) of the connecting portion 61 are set to be substantially the same. The vertical height (length) of the extending portion 62 of the inner cylinder portion 6 in the front mount 4a is set to about half of the vertical height (length) of the connecting portion 61. However, the ratio of the vertical height (length) of the extending portion 62 and the connecting portion 61 in the present invention can be set as appropriate.

  Moreover, in the said embodiment, although it is assumed that the extended part 62 is provided in the inner cylinder part 6 of both the front mount 4a and the rear mount 4b, this invention is the front mount 4a, the rear mount 4b, It is also possible to adopt a configuration in which only one of these is provided with the extended portion 62.

  In the above embodiment, it is assumed that the elastic body 7 having the same size and shape is used in both the front mount 4a and the rear mount 4b. However, in the present invention, the front mount 4a and the rear mount 4b It is also possible to adopt a configuration in which elastic bodies 7 having different sizes and shapes are used.

DESCRIPTION OF SYMBOLS 1 Subframe fastening structure 2 Body frame 3 Subframe 4 Mount 4a Front part 4b Rear part 5 Outer cylinder part 6 Inner cylinder part 7 Elastic body 10 Car body rear part structure 11 Rear side frame 14 Front cross member 15 Rear cross member 18 Rear suspension 18a Upper arm (suspension arm)
18b Lower arm (suspension arm)
18c Control arm (suspension arm)
34 Fastening part 35 Fastening part 38 Bolt 39 Nut 51 Sub-side member (vertical member)
52 Sub cross member 54 Knuckle C Elastic center D1 Distance D2 Distance Ft Lateral force P Fastening point R Roll center

Claims (4)

A subframe fastening structure for fastening a subframe to which a suspension arm of a rear wheel of a vehicle is pivotally attached to a vehicle body frame of the vehicle,
The sub-frame includes left and right vertical members extending in the front-rear direction of the vehicle,
The vertical member is floatingly supported with respect to the vehicle body frame by a front mount disposed at a front end portion of the vertical member and a rear mount disposed at a rear end portion of the vertical member,
Each of the front mount and the rear mount includes an inner cylinder portion fastened to the vehicle body frame side,
An outer cylinder part attached to the subframe side;
An elastic body connecting the inner cylinder part and the outer cylinder part,
The front mount and the rear mount are:
A sub-frame fastening structure characterized in that a distance between a fastening point of the inner cylinder part to the body frame and an elastic center of the elastic body are different from each other. The left and right vertical members of the subframe are curved such that the rear end of the vertical member is higher than the front end,
The distance between the fastening point of the inner cylinder portion to the vehicle body frame and the elastic center of the elastic body is larger in the rear mount than in the front mount. Sub-frame fastening structure. The inner cylinder part is connected to the inner side of the outer cylinder part via the elastic body,
The subframe fastening structure according to claim 1, further comprising: an extending portion extending toward the vehicle body frame from the connecting portion. The sub-frame fastening structure according to claim 1, wherein the body frame has a straight shape in the front-rear direction of the vehicle above the vertical member.

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