JP2013082333A - Subframe structure and vehicle body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a subframe structure which can improve a strength of the subframe at low cost without extremely increasing weight.SOLUTION: The subframe structure, in which a suspension arm is attached to a subframe 1 arranged beneath the vehicle body, wherein: wires 5a and 5b are arranged in the subframe 1 as a tensing means for generating a tension in a direction resisting a bending moment generated in a surface of the subframe 1 when a load in a width direction of the vehicle body is applied to attachments 4a and 4b of the suspension arm; and the wires 5a and 5b are arranged along a side surface at a side to which a tension of the subframe 1 is applied when the bending moment is generated.

Description

  The present invention relates to a subframe structure in which a suspension arm is attached to a subframe disposed at a lower portion of a vehicle body, and a vehicle body having such a subframe structure.

  2. Description of the Related Art In order to increase the mounting rigidity of a suspension to a vehicle body, a subframe structure in which a suspension arm is attached to a subframe disposed at the lower part of the vehicle body is widely used in a vehicle body structure.

  In this subframe structure, for example, a subframe 100 shown in FIGS. 10A and 10B, a pair of left and right side members 101a and 101b extending in the full length direction of the vehicle body, and front and rear extending in the width direction of the vehicle body. In some cases, the pair of cross members 102a and 102b are connected in a frame shape, and suspension arm attachment portions 103a and 103b are provided on both sides of the side members 101a and 101b, respectively.

  In the subframe 100 having such a structure, for example, when a load in the width direction of the vehicle body (hereinafter referred to as a lateral load) P1 ′ and P2 ′ is applied from the tire to the mounting portions 103a and 103b of the suspension arm during cornering, A bending moment M ′ corresponding to the lateral loads P1 ′ and P2 ′ is generated in the plane of the frame 100, and the side members 101a and 101b and the cross members 102a and 102b are shown by broken lines in FIGS. 10 (a) and 10 (b). Elastic deformation (bending) as shown occurs. Further, when the lateral loads P1 'and P2' applied to the subframe 100 increase, plastic deformation of the subframe 100 is also started.

  Such deformation of the subframe 100 causes a change in suspension geometry, which adversely affects the running performance of the automobile. For the subframe 100, generally, a steel material such as a steel plate or steel pipe formed into a predetermined shape and joined by welding or the like is used. Therefore, in order to increase the strength of the subframe 100, it is conceivable to use a steel material having a large plate thickness or a high-strength steel material.

  However, increasing the thickness of the steel material leads to an increase in the weight of the sub-frame, and thus increases the vehicle weight, thereby deteriorating the running performance and fuel consumption of the automobile. On the other hand, a high-strength steel material generally has an elongation ratio that is inversely proportional to its strength, and easily deteriorates formability. In addition, using a relatively expensive high-strength steel material leads to an increase in the cost of the vehicle body.

  In addition, as a prior art document relevant to this invention, the following patent documents 1-6 can be mentioned, for example. Specifically, these Patent Documents 1 to 6 disclose techniques that use the tension of a wire in order to reduce, absorb, or disperse an impact applied to a vehicle body, a frame, or the like at the time of a car collision. However, each of these techniques is completely different from the technique for improving the strength of the subframe, which is the object of the present invention.

JP 2005-199749 A JP 2005-262951 A JP-A-2005-306324 JP 2005-329766 A JP 2009-161106 A JP 2010-006221 A

  The present invention has been proposed in view of such a conventional situation, and the object thereof is a subframe structure capable of improving the strength of the subframe at a low cost without incurring an extreme weight increase, and It is an object of the present invention to provide a vehicle body having such a light and strong subframe structure.

The gist of the present invention aimed at solving the above problems is as follows.
(1) A sub-frame structure in which a suspension arm is attached to a sub-frame disposed at a lower part of a vehicle body,
The sub-frame is provided with tension means for generating a tension in a direction against a bending moment generated in the plane of the sub-frame when a load in the width direction of the vehicle body is applied to the attachment portion of the suspension arm. A subframe structure characterized in that
(2) The sub-frame structure according to (1), wherein the tension means includes a wire stretched on the sub-frame.
(3) The subframe structure according to (2), wherein the wire is disposed along a side surface to which a tensile tension of the subframe is applied when the bending moment is generated.
(4) The sub-frame connects a pair of left and right side members extending in the full length direction of the vehicle body and a pair of front and rear cross members extending in the width direction of the vehicle body in a frame shape, and on each side of the side member. The subframe structure according to any one of (1) to (3), wherein the suspension arm mounting portion is provided.
(5) The tension means is configured such that the wire is connected to the inner side and the outer side of the subframe through holes provided at positions where the direction of the bending moment generated in the plane of the subframe of the side member and the cross member is switched. The subframe structure according to (4), wherein the subframe structure has a structure routed between the subframes.
(6) The tension means is a structure in which the wire is stretched between latching portions provided at positions where the direction of the bending moment generated in the plane of the sub frame of the side member and the cross member is switched. (4) The subframe structure according to (4),
(7) The subframe structure according to (5) or (6), wherein the wires are arranged symmetrically with respect to the subframe.
(8) A vehicle body having the sub-frame structure according to any one of (1) to (7).

  As described above, in the subframe structure according to the present invention, when a load in the width direction of the vehicle body is applied to the attachment portion of the suspension arm, the tension in the direction against the bending moment generated in the plane of the subframe is applied. By providing the tension means to be generated on the subframe, it is possible to improve the strength of the subframe at a low cost without causing an extreme increase in weight. Therefore, according to the present invention, it is possible to provide a vehicle body having such a light-weight and strong sub-frame structure.

It is a plane schematic diagram which shows an example of the sub-frame structure to which this invention is applied. It is a perspective view which expands and shows the principal part of the sub-frame structure shown in FIG. It is a plane schematic diagram which shows arrangement | positioning of one wire of the sub-frame structure shown in FIG. It is a plane schematic diagram which shows arrangement | positioning of the other wire of the sub-frame structure shown in FIG. FIG. 4 is a schematic plan view for explaining deformation of the subframe when a lateral load in the right direction is applied to the subframe in which one wire shown in FIG. 3 is arranged. FIG. 5 is a schematic plan view for explaining deformation of the subframe when a lateral load in the left direction is applied to the subframe in which the other wire shown in FIG. 4 is arranged. It is a graph which shows the relationship of the load-load point displacement of the sub-frame structure of this invention, and the conventional sub-frame structure. It is a plane schematic diagram which shows the other examples of the sub-frame structure to which this invention is applied. It is a plane schematic diagram which shows the other examples of the sub-frame structure to which this invention is applied. (A) is a schematic plan view showing a state before and after deformation when a lateral load in the right direction of the subframe is applied. (B) is a schematic plan view showing a state before and after deformation when a lateral load in the left direction of the subframe is applied.

Hereinafter, a frame structure and a vehicle body to which the present invention is applied will be described in detail with reference to the drawings.
In the frame structure to which the present invention is applied, a sub-frame to which a suspension arm is attached is arranged at the lower part of the vehicle body. The present invention is applied to a rear subframe that supports the frame.

  In addition, the subframe structure of the present invention may be a structure in which the subframe is directly attached to the lower part of the vehicle body or a structure in which the subframe structure is attached via an anti-vibration mount (insulator).

  The subframe is generally formed by welding a steel material such as a steel plate or steel pipe into a predetermined shape by welding or the like, but also in the present invention, conventionally known materials and manufacturing methods are used. It is possible to use the created subframe.

FIG. 1 is a schematic plan view showing an example of a frame structure to which the present invention is applied.
The frame structure to which the present invention is applied includes a sub-frame 1 as shown in FIG. 1, and this sub-frame 1 has a pair of left and right side members 2a, 2b extending in the entire length direction of the vehicle body, and front and rear surfaces extending in the width direction of the vehicle body. The pair of cross members 3a and 3b are connected in a frame shape, and suspension arm mounting portions 4a and 4b are provided on both sides of the side members 2a and 2b, respectively.

  The subframe 1 shown in FIG. 1 has a left side member 2a and a right side member 2a that are equal in length, the rear cross member 3b is shorter than the front cross member 3a, and has a rectangular frame shape as a whole. ing. Further, the suspension arm mounting portions 4a and 4b are arranged at positions where the pair of side members 2a and 2b are symmetrical, and are provided to protrude outward.

  The subframe 1 resists bending moment generated in the plane of the subframe 1 when a load in the width direction of the vehicle body (hereinafter referred to as a lateral load) is applied to the suspension arm mounting portions 4a and 4b. Tensioning means for generating a tension in the direction is provided.

  Specifically, in the present invention, a pair of wires 5a and 5b stretched on the subframe 1 are used as such tension means. These wires 5a and 5b only need to generate sufficient tension to resist the bending moment generated in the plane of the subframe 1, and for example, steel wires or steel stranded wires can be used. .

  The pair of wires 5 a and 5 b are arranged symmetrically with respect to the subframe 1. Of these wires, one wire 5a is generated in the plane of the subframe 1 when a lateral load is applied in the right direction (one direction) from the tire to the mounting portions 4a and 4b of the suspension arm during cornering, for example. It generates tension in a direction against the bending moment.

  On the other hand, the other wire 5b is placed in the plane of the subframe 1 when a lateral load is applied from the tire toward the left direction (the other direction) from the tire to the mounting portions 4a and 4b of the suspension arm during cornering, for example. It generates tension in the direction against the bending moment that occurs.

  As shown in FIGS. 1 and 2, the pair of wires 5a and 5b are provided at positions where the direction of the bending moment generated in the plane of the subframe 1 of the side members 2a and 2b and the cross members 3a and 3b is switched. The holes 6a to 6l are routed between the inner side and the outer side of the subframe 1.

  Specifically, as shown in FIG. 3, the one wire 5a passes through the holes 6a and 6b provided at the front and rear of the right side member 2b, and the outer side surface of the right side member 2b between these holes 6a and 6b. Has been routed along. One wire 5a passes through holes 6a and 6b provided in the front and rear of the right side member 2b and holes 6c and 6f provided in the center of the front and rear cross members 3a and 3b. Between the parts 6a, 6b, 6c, 6f, they are routed along the inner surfaces of the front and rear cross members 3a, 3b, respectively. One wire 5a includes holes 6c and 6f provided at the center of the front and rear cross members 3a and 3b, and holes 6d and 6e provided on the left side of the front and rear cross members 3a and 3b. Between the holes 6c, 6f, 6d, and 6e along the outer surfaces of the front and rear cross members 3a and 3b. One wire 5a is pulled along the inner surface of the left side member 2a between the holes 6d and 6e through the holes 6d and 6e provided on the left side of the front and rear cross members 3a and 3b. It has been turned.

  On the other hand, as shown in FIG. 4, the other wire 5b passes through the holes 6g and 6h provided at the front and rear of the left side member 2a, and is outside the left side member 2a between the holes 6g and 6h. It is routed along the side. The other wire 5b passes through the holes 6g and 6h provided at the front and rear of the left side member 2a and the holes 6i and 6l provided at the center of the front and rear cross members 3a and 3b. Between the portions 6g, 6h, 6i, and 6l, they are routed along the inner surfaces of the front and rear cross members 3a and 3b, respectively. The other wire 5b includes holes 6i and 6l provided at the center of the front and rear cross members 3a and 3b and holes 6j and 6k provided on the right side of the front and rear cross members 3a and 3b. Are routed along the outer surfaces of the front and rear cross members 3a and 3b between the holes 6i, 6l, 6j and 6k, respectively. The other wire 5b is pulled along the inner surface of the right side member 2b between the holes 6j and 6k through the holes 6j and 6k provided on the right side of the front and rear cross members 3a and 3b. It has been turned.

  Since the holes 6c and 6f and the holes 6i and 6l provided in the center of the front and rear cross members 3a and 3b have the same arrangement, a common hole through which the pair of wires 5a and 5b is passed. You may form as a part. Further, in the thickness direction of the subframe 1, the positions of the holes 6c and 6f and the holes 6i and 6l may be shifted and the pair of wires 5a and 5b may be passed separately.

  In the subframe structure having the above-described structure, as shown in FIGS. 5 and 6, for example, when lateral loads P1 and P2 are applied from the tire to the suspension arm mounting portions 4a and 4b during cornering, the subframe 1 Bending moments M1 to M12 corresponding to the lateral loads P1 and P2 are generated in the plane.

  At this time, although the elastic deformation (bending) as shown in FIGS. 5 and 6 occurs in the subframe 1, in the present invention, the tensile force of the side members 2a and 2b and the cross members 3a and 3b is applied. Since the pair of wires 5a and 5b are arranged along the side surfaces, tension in a direction against the bending moments M1 to M12 generated in the plane of the subframe 1 can be generated by the wires 5a and 5b.

  Specifically, as shown in FIG. 5, when a lateral load P1 in the right direction is applied to the suspension arm attachment portions 4a and 4b, the left side member 2a constituting the subframe 1 is pulled inside. A bending moment M1 is generated. At this time, one wire 5a disposed along the side surface (ie, the inner surface) to which the tensile force of the left side member 2a is applied generates a tension in a direction against the bending moment M1.

  Further, the right side member 2b constituting the subframe 1 generates a bending moment M2 in which the outside is pulled. At this time, one wire 5a arranged along the side surface (ie, the outer surface) to which the tensile force of the right side member 2b is applied generates a tension in a direction against the bending moment M2.

  Further, the front cross member 3a constituting the subframe 1 has a bending moment M3 in which the outside is pulled on the left side across the center and a bending moment M4 in which the inside is pulled on the right side across the center. To do. At this time, one of the wires 5a arranged along the side surface (ie, the left outer surface and the right inner surface) to which the tensile force of the front cross member 3a is applied is in a direction against the bending moments M3 and M4. Generate tension.

  Further, the rear cross member 3b constituting the subframe 1 has a bending moment M5 in which the outside is pulled on the left side with the center interposed therebetween, and a bending moment M6 in which the inside is pulled on the right side with the center interposed. Occur. At this time, the direction in which one wire 5a arranged along the side surface (ie, the left outer surface and the right inner surface) to which the tensile force of the rear cross member 3b is applied resists the bending moments M5 and M6. Generate tension.

  Thereby, it is possible to suppress the deformation of the subframe 1 when the lateral load P1 in the right direction is applied to the subframe 1.

  On the other hand, as shown in FIG. 6, when a left lateral load P2 is applied to the suspension arm attachment portions 4a and 4b, the left side member 2a constituting the subframe 1 has a bending moment at which the outside is pulled. M7 is generated. At this time, the other wire 5b arranged along the side surface to which the tensile tension of the left side member 2a is applied (that is, the outer surface) generates a tension in a direction against the bending moment M7.

  In addition, a bending moment M8 in which the inner side is pulled is generated in the right side member 2b constituting the subframe 1. At this time, the other wire 5b arranged along the side surface (that is, the inner side surface) to which the tensile tension of the right side member 2b is applied generates a tension in a direction against the bending moment M8.

  Further, the front cross member 3a constituting the subframe 1 has a bending moment M9 in which the inner side is pulled on the left side with the center interposed therebetween, and a bending moment M10 in which the outer side is pulled on the right side with the center interposed therebetween. To do. At this time, the other wire 5b arranged along the side surface to which the tensile tension of the front cross member 3a is applied (that is, the left inner surface and the right outer surface) is in a direction against the bending moments M9 and M10. Generate tension.

  Further, the rear cross member 3b constituting the subframe 1 has a bending moment M11 in which the inner side is tensioned on the left side of the center and a bending moment M12 in which the outer side is tensioned on the right side of the center. Occur. At this time, the other wire 5b arranged along the side surface (ie, the left inner surface and the right outer surface) to which the tensile force of the rear cross member 3b is applied resists the bending moments M11 and M12. Generate tension.

  Thereby, it is possible to suppress the deformation of the subframe 1 when the lateral load P2 in the left direction is applied to the subframe 1.

  As described above, in the subframe structure to which the present invention is applied, the deformation of the subframe 1 shown in FIGS. 5 and 6 can be suppressed, and the subframe can be inexpensively produced without causing an extreme weight increase. The strength of 1 can be improved.

  Further, in the subframe structure to which the present invention is applied, as shown in the graph of FIG. 7, the conventional subframe structure in which the tension means (wires 5a and 5b) shown in FIGS. 10 (a) and 10 (b) is not provided. Compared to the frame structure 100, it is possible to delay the start of plastic deformation with respect to an increase in load applied to the subframe 1. In other words, in the subframe structure to which the present invention is applied, it is possible to increase the load at which plastic deformation of the subframe 1 is started as compared with the conventional case.

  Therefore, in the present invention, by obtaining a vehicle body having such a light and strong subframe structure, it is possible to significantly improve the running performance of the automobile while suppressing changes in the suspension geometry. .

In addition, this invention is not necessarily limited to the thing of the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
In the following description, portions equivalent to the subframe structure shown in FIG. 1 are not described and are denoted by the same reference numerals in the drawings. In the present invention, although the wires (tensioning means) are arranged symmetrically in the left and right in the subframe, for the sake of convenience, only the wires arranged on either the left or right side are illustrated in the following drawings. Shall also be omitted.

  In the present invention, for example, the subframe structure shown in FIG. 8 may be used. Specifically, this sub-frame structure has a structure in which the wire 5c is arranged along the side surface of the side members 2a and 2b on the side where the tensile tension is applied.

  In other words, the present invention is not limited to the structure in which the pair of wires 5a and 5b are routed around the entire circumference of the subframe 1 as in the subframe structure shown in FIG. It is also possible to adopt a structure in which the wire 5c is partially disposed on the side surface of the.

  Further, in the present invention, for example, the subframe structure shown in FIG. 9 may be used. Specifically, this sub-frame structure is formed between the latching portions 7 provided at positions where the direction of the bending moment generated in the plane of the sub-frame 1 of the side members 2a and 2b and the cross members 3a and 3b is switched. It has a structure in which a wire 5d is stretched.

  That is, in the present invention, as in the subframe structure shown in FIG. 1, instead of passing the wires 5 a and 5 b through the holes 6 i to 6 j provided in the subframe 1, a loop shape is formed between the hooking portions 7. It is also possible to adopt a structure in which the wire 5d is arranged along the side surface of the subframe 1 to which the tensile tension is applied by spanning the wire 5d.

  Moreover, in this invention, it is also possible to set it as the structure which stretched the wire combining the hole part and latching part which were mentioned above according to the shape etc. of the sub-frame.

  The tension means of the present invention may be any tension means that generates tension in a direction against the bending moments M1 to M12 generated in the plane of the subframe 1, and is stretched on the subframe 1 described above. It is not necessarily limited to the wires 5a and 5b. For example, a rod (bar) is used in place of the wires 5a and 5b, and the rod (bar) is arranged along the side surface of the subframe 1 to which the tensile tension is applied while bending at a position where the direction of the bending moment is switched. It is also possible to adopt the configuration described above. Further, such a rod (bar) may be partially arranged on the side surface of the subframe 1 on the side to which the tensile tension is applied.

  The sub-frame structure to which the present invention is applied is a structure in which the sub-frame 1 in which the pair of left and right side members 2a and 2b and the pair of front and rear cross members 3a and 3b are connected in a frame shape is attached to the lower part of the vehicle body. It is not necessarily limited. For example, among the members 2a, 2b, 3a, 3b constituting the subframe 1, some members may constitute a part of the main frame constituting the vehicle body.

  DESCRIPTION OF SYMBOLS 1 ... Sub-frame 2a ... Left side member 2b ... Right side member 3a ... Front side cross member 3b ... Rear side cross member 4a, 4b ... Suspension arm attachment part 5a ... One wire (tensile means) 5b ... The other wire (tension) Means) 6a to 6l ... hole 7 ... hanging portion

Claims (8)

A sub-frame structure in which a suspension arm is attached to a sub-frame arranged at the bottom of the vehicle body,
The sub-frame is provided with tension means for generating a tension in a direction against a bending moment generated in the plane of the sub-frame when a load in the width direction of the vehicle body is applied to the attachment portion of the suspension arm. A subframe structure characterized in that   The sub-frame structure according to claim 1, wherein the tension means includes a wire stretched on the sub-frame.   3. The subframe structure according to claim 2, wherein the wire is disposed along a side surface to which a tensile tension of the subframe is applied when the bending moment is generated.   The sub-frame connects a pair of left and right side members extending in the entire length direction of the vehicle body and a pair of front and rear cross members extending in the width direction of the vehicle body in a frame shape, and the suspension arms on both sides of the side member. The sub-frame structure according to claim 1, wherein the sub-frame structure has a structure provided with a mounting portion.   The tension means is formed between the inner side and the outer side of the subframe through a hole provided at a position where the direction of the bending moment generated in the plane of the subframe of the side member and the cross member is switched. 5. The subframe structure according to claim 4, wherein the subframe structure has a routed structure.   The tension means has a structure in which the wire is stretched between latching portions provided at positions where the direction of the bending moment generated in the plane of the subframe of the side member and the cross member is switched. The subframe structure according to claim 4, wherein:   The subframe structure according to claim 5 or 6, wherein the wires are arranged symmetrically with respect to the subframe.   A vehicle body having the sub-frame structure according to claim 1.

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