JP3900937B2 - Subframe support structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a support structure such as a subframe and a suspension member that are supported on a vehicle body via a mount insulator.
[0002]
[Prior art]
As a conventional support structure of this type of subframe, for example, a technique described in Japanese Patent Publication No. 07-47974 is known.
When the structure of the above publication is shown in FIG. 4, both ends of the subframe 2 are elastically supported on the vehicle body 6 side via mount insulators 4 (referred to as elastic bushes in the publication). Further, wheel support members such as suspension links and suspension arms are elastically supported.
[0003]
The mount insulator 4 is roughly configured by an inner cylinder 4a, an outer cylinder 4b, and an elastic body 4c loaded between the inner cylinder 4a and the outer cylinder 4b on the upper outer peripheral side of the inner cylinder 4a. A mounting cylinder 8 having an axial length longer than that of the outer cylinder 4b is fixed to the end of the subframe 2 by welding or the like, and the outer cylinder 4b is fixed inside the upper end of the mounting cylinder 8 by press-fitting.
On the other hand, a mounting pin 10 is hanged downward from the vehicle body 6, and the inner cylinder 4 a of the mount insulator 4 is externally attached to the mounting pin 10 and screwed to a screw portion 10 a at the lower end portion of the mounting pin 10. By tightening the nut 12, the inner cylinder 4 a and the mounting pin 10 are coupled.
[0004]
According to the support structure of the subframe 2 configured as described above, road surface vibrations from wheels (not shown) input to the subframe 2 are significantly reduced from being input to the vehicle body 6 by the buffer function of the mount insulator 4. can do.
[0005]
[Problems to be solved by the invention]
By the way, it is currently required to share vehicle parts from the viewpoint of cost reduction. In order to deal with different types of vehicles with different ground clearances using a common subframe, the vertical direction of the vehicle body and the subframe is relatively low. It is necessary to change the distance.
Here, when the support structure of the subframe shown in FIG. 4 is adopted to cope with a vehicle type having a high minimum ground clearance, the vertical distance between the vehicle body 6 and the subframe 2 is increased, that is, the subframe 2 is increased. In order to position the mounting pin 10 downward, it is necessary to increase the axial length of the mounting pin 10 that is suspended downward from the vehicle body 6.
[0006]
When the axial length of the mounting pin 10 is increased, the elastic body 4a is positioned downward, and the distance from the vehicle body 6 to the elastic center P of the mount insulator 4 increases. Thus, the distance from the vehicle body 6 to the elastic center P is large. As a result, the moment span of the mounting pin 10 is increased by the vibration input to the subframe 2 from the wheel support member such as the suspension link or the suspension arm. As described above, when the moment span of the mounting pin 10 increases, the amount of deformation of the vehicle body 6 increases due to an increase in the bending moment of the mounting pin 10, which may reduce the vibration performance such as the sound vibration performance in the vehicle.
[0007]
The present invention has been made in view of the above circumstances, and it is possible to prevent a decrease in vibration performance such as sound vibration performance even if a common subframe is used to cope with different vehicle types having a minimum ground clearance. An object of the present invention is to provide a subframe support structure that can reduce the cost by sharing the components of the mount insulator.
[0008]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a subframe support structure comprising: an inner cylinder, an outer cylinder, and an elastic body loaded between the inner cylinder and the outer cylinder; A structure in which the subframe is swingably supported on the vehicle body via the mount insulator by being inserted and coupled to the inner cylinder of the mount insulator provided and fixing the subframe to the outer cylinder side. The vehicle vertical direction of the subframe with respect to the vehicle body is changed by changing the vehicle vertical direction fixing position of the subframe with respect to the outer cylinder without changing the vehicle vertical position of the elastic body with respect to the vehicle body. The position of was changed.
[0009]
According to a second aspect of the present invention, in the subframe support structure according to the first aspect, a mounting cylinder is fixed to the subframe, and the mounting cylinder is fitted over the outer cylinder of the mount insulator so that It is characterized by being fixed at a predetermined position in the direction.
Furthermore, the invention according to claim 3 is the subframe support structure according to claim 1 or 2, wherein the mounting cylinder has a constant axial length, and the outer cylinder of the mount insulator has a longer axial length than the mounting cylinder. As a member to be provided, a receiving portion for receiving the lower end of the externally fitted mounting cylinder is provided at the lower end portion of the outer cylinder.
[0010]
【The invention's effect】
According to the first aspect of the present invention, even if the position of the vehicle in the vertical direction of the subframe relative to the vehicle body is changed in order to cope with different vehicle types having different minimum ground clearances, the elastic body of the mount insulator relative to the vehicle body in the vehicle vertical direction. Since the position does not change, the elastic center of the mount insulator is always constant. Thus, if the elastic center is constant even if the position of the subframe in the vehicle vertical direction is changed with respect to the vehicle body, the vibration characteristics when the input from the subframe is transmitted to the vehicle body is constant. Vibration performance such as sound vibration performance does not deteriorate.
[0011]
According to the subframe support structure of claim 2 or 3, the mounting cylinder is fixed to the subframe, and the mounting cylinder is externally fitted to the outer cylinder of the mount insulator and fixed at a predetermined position in the vehicle vertical direction. Therefore, the subframe can be shared, the mounting pin and the inner cylinder of the mount insulator can be shared, and the cost of vehicle parts can be reduced.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of a subframe support structure of the present invention will be described with reference to the drawings.
FIG. 1 is a plan view showing a suspension member 20 according to the present invention, and a pair of side members 22, 22 arranged in the vehicle width direction while extending in the vehicle front-rear direction, and these side members 22, A rear cross member 24 that extends and is fixed in the vehicle width direction on the rear side in the vehicle front-rear direction of 22, and extends in the vehicle width direction on the front side in the vehicle front-rear direction from the rear cross member 24. And a front cross member 26 fixed to the side members 22 and 22.
[0013]
The pair of side members 22, 22 is bent inward in the vehicle width direction at the center in the longitudinal direction, and extends in the vehicle front-rear direction while drawing a substantially arc as a whole.
A mounting surface 30 for the front cross member 26 is provided on the front side surface of the side members 22 and 22 in the vehicle front-rear direction, and both end portions of the front cross member 26 are fixed to the mounting surface 30 by welding. ing. Further, attachment surfaces 32 of the rear cross member 24 are also provided on the rear side surfaces of the side members 22 and 22 in the vehicle front-rear direction, and both end portions of the rear cross member 24 are welded to the attachment surfaces 30. It is fixed by.
[0014]
Mount insulators 34 and 36 are respectively attached to a front end portion and a rear end portion of the suspension member 20 in the vehicle front-rear direction, and the suspension member 20 is elastically supported by the vehicle body via the mount insulators 34 and 36.
Further, a pin 38 is fixed to the front end portion of the pair of side members 22, 22 of the suspension member 20 in the vehicle front-rear direction, and wheel support members such as a suspension link and a suspension arm are swingable on the pin 38. It is the structure which can be connected to.
[0015]
Next, FIG. 2 is a view showing in detail the structure in which the suspension member 20 is elastically supported by the vehicle body 42 via the mount insulator. In this figure, the structure in which the rear end portions of the pair of side members 22 and 22 are elastically supported by the vehicle body 42 via the mount insulator 36 will be described. However, the structure is arranged at the front end portions of the pair of side members 22 and 22. Since the structure elastically supported by the vehicle body 42 via the mount insulator 34 is the same structure, illustration and description are omitted.
[0016]
The mount insulator 36 includes an inner cylinder 44, an outer cylinder 46, and an elastic body 48 that is loaded between these inner and outer cylinders 44 and 46 by vulcanization adhesion or the like.
The elastic body 48 includes an elastic main body portion 48a having an axial length set to L1 and performing a buffer function, and an elastic stopper portion 48b that prevents excessive deformation of the elastic main body portion 48a continuously from the lower portion of the elastic main body portion 48a. It consists of
[0017]
The inner cylinder 44 is covered with an elastic main body portion 48 a substantially in the entire outer periphery, and the upper end surface is in contact with the lower surface of the vehicle body 42. The outer cylinder 46 is set to an axial length L2 (L2 <L1) that covers substantially the entire area of the elastic body 48a and the elastic stopper 48b of the elastic body 48, and is a bent portion that extends radially outward at the lower end. 46a is formed.
Further, an insulator collar 50 as a mounting cylinder having an axial length L3 set shorter than the outer cylinder 46 of the mount insulator 36 (L3 <L2) is fixed to the end of the side member 22 (suspension member 20) by welding or the like. Yes. The insulator collar 50 is fitted into the outer periphery of the outer cylinder 46 by press fitting, and the bent portion 46 a receives the lower end of the insulator collar 50.
[0018]
Further, a mounting pin 52 is provided downward from the vehicle body 42, and the inner cylinder 44 of the mount insulator 36 is externally attached to the mounting pin 52. And the inner cylinder 44 and the attachment pin 52 are couple | bonded by tightening the nut 54 screwed by the thread part 52a of the lower end part of the attachment pin 52. As shown in FIG. A washer 56 and a collar portion 58 are interposed between the lower end of the inner cylinder 44 and the nut 54.
Here, the protruding length of the mounting pin 52 from the lower portion of the vehicle body 42 is L4. The central portion of the elastic main body 48a in the axial direction is the elastic center P1 of the mount insulator 36. The distance from the lower surface of the vehicle body 42 to the elastic center P1 of the mount insulator 36 is set to a distance L5.
[0019]
By the way, in the present embodiment, the shape of the elastic body of the mount insulator is partially changed and the outer cylinder is used as a changed part in order to share the suspension member 20 and cope with different vehicle types having different minimum ground clearances.
That is, FIG. 3 shows an elastic body (hereinafter referred to as a modified elastic body) 48A and an outer cylinder (hereinafter referred to as a modified outer cylinder) 46A while sharing the suspension member 20 with respect to the structure shown in FIG. A suspension member support structure in which the minimum ground clearance is lowered by using the adopted mount insulator 36A is shown.
[0020]
Compared with the elastic body 48 shown in FIG. 2, the changed elastic body 48A has an elastic main body 48a having the same axial length (L1) and a short length continuously downward from the lower portion of the elastic main body 48a. And an elastic stopper portion 48c extending in the direction.
The outer cylinder 46A is set to a member whose axial length L6 is shorter than the outer cylinder 46 shown in FIG. 2 (L6 <L2) and covers substantially the entire area of the elastic main body 48a and the elastic stopper 48c of the elastic body 48 (L6 <L2). A bent portion 46c is formed extending outward in the radial direction.
[0021]
Further, the insulator collar 50 having the same shape used in FIG. 2 is fixed to the end of the side member 22 (suspension member 20). The axial length L6 of the outer cylinder 46A described above is set slightly longer than the axial length L3 of the insulator collar 50 (L3 <L6).
The insulator collar 50 is fitted into the outer periphery of the outer cylinder 46A by press fitting, and the bent portion 46a receives the lower end of the insulator collar 50, whereby the suspension member 20 (20) elastically supported by the vehicle body 42 is The distance in the vertical direction with respect to the vehicle body 42 is smaller than that in the structure of FIG. 2, and the suspension member 20 is supported with a minimum ground clearance.
[0022]
Also, the same mounting pin 52 is used in the structure of FIG. 3 (the length of protrusion of the mounting pin 52 from the lower portion of the vehicle body 42 is L4), and the vertical position of the elastic body 48a is also shown in FIG. Since it is not different from the structure, the distance from the lower surface of the vehicle body 42 to the elastic center P1 of the mount insulator 36A is set to the same distance (L5) as FIG.
Therefore, even if the structure of FIG. 2 is changed to the structure of FIG. 3, that is, even if the suspension member support structure is changed in order to increase the minimum ground clearance while sharing the suspension member 20, the minimum ground clearance is changed. Since the position of the elastic center (P1) of the mount insulator 36 and the position of the elastic center (P1) of the changed mount insulator 36A are always constant with respect to the vehicle body 42, the input to the suspension member 20 from the wheel support member. Since the bending moment to the mounting pin 52 due to the vibration that occurs does not change, and the deformation amount of the vehicle body does not change, the vibration performance such as sound vibration performance does not deteriorate.
[0023]
Conversely, if the structure shown in FIG. 3 is changed to the structure shown in FIG. 2, that is, if the suspension member support structure is changed in order to reduce the minimum ground clearance while sharing the suspension member 20, the minimum ground clearance is similarly reduced. Since the position of the elastic center (P1) of the mount insulator before the change and the position of the elastic center (P1) of the mount insulator after the change are always constant with respect to the vehicle body 42, vibration performance such as sound vibration performance Does not drop.
[0024]
Further, since the suspension member 20 can be shared, the insulator collar 50, the mounting pin 52, and the inner cylinder 44 of the mount insulators 36, 36A that are fixed to the pair of side members 22, 22 can be shared. The cost of parts can be reduced.
In this embodiment, the suspension member 20 that supports the wheel support members such as the suspension link and the suspension arm is shown. However, the gist of the present invention is not limited to this, and the suspension member 20 is applied to the subframe that supports the engine. Even in this case, similar effects can be obtained.
[Brief description of the drawings]
FIG. 1 is a plan view showing an overall structure of a subframe according to the present invention.
FIG. 2 is a partial cross-sectional view showing the structure of a subframe supported by a vehicle body via a mount insulator.
FIG. 3 is a partial cross-sectional view showing a support structure of a subframe in which the minimum ground clearance is changed.
FIG. 4 is a diagram illustrating a conventional subframe support structure.
[Explanation of symbols]
20 Suspension member (subframe)
22 Side member 24 Rear cross member 26 Front cross member 34, 36, 36A Mount insulator 42 Car body 44 Inner cylinder 46, 46A Outer cylinder 46a, 46c Bent part (receiving part)
48,48A Elastic body 50 Insulator collar (mounting cylinder)
52 Mounting pin P1 Elastic center

Claims (3)

A mounting pin suspended downward from the vehicle body is inserted and coupled to the inner cylinder of the mount insulator provided with an inner cylinder, an outer cylinder, and an elastic body loaded between the inner cylinder and the outer cylinder, In the structure in which the sub frame is swingably supported by the vehicle body via the mount insulator by fixing the sub frame to the outer cylinder side.
The vertical position of the subframe relative to the outer cylinder is changed without changing the vertical position of the elastic body relative to the vehicle body. A sub-frame support structure characterized by changing a position. The support structure for a subframe according to claim 1, wherein a mounting cylinder is fixed to the subframe, and the mounting cylinder is externally fitted to the outer cylinder of the mount insulator and fixed at a predetermined position in the vehicle vertical direction. . The mounting cylinder has a fixed axial length, the outer cylinder of the mount insulator is a member having a longer axial length than the mounting cylinder, and a receiving portion that receives the lower end of the mounting cylinder that is externally fitted to the lower end of the outer cylinder. The subframe support structure according to claim 1, wherein the subframe support structure is provided.

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