JP2009227216A - Lower vehicle body structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively absorb a collision load during frontal collision by compressing a frame shaft. <P>SOLUTION: An X-shaped second cross member 132 instead of a conventional second cross member is formed between right and left main frames 122, 122 by a pair of skew members 134, 134. To a combined part 180 where the pair of skew members 134, 134 cross each other at their longitudinal intermediate portions, a transmission mount member 182 is fixed with a common bolt. Thereby, the skew members 134, 134 are connected to each other. A catalyst container 194 is arranged in a top-view triangular region which is formed on the sides of the crossing skew members 134, 134. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle body lower structure, and more particularly to a vehicle body lower structure including left and right main frames that extend in a vehicle longitudinal direction from a front end to a rear end, which is employed in a truck or the like.

  As seen in Patent Documents 1 and 2, a truck generally has left and right main frames, the main frame extends from the front end of the vehicle body to the rear end, and a cross member is disposed between the left and right main frames in the vehicle longitudinal direction. A lower structure, that is, a frame structure, is used in which a plurality of them are arranged at intervals.

  8 and 9 show a conventional track frame structure. A conventional truck 1 has left and right main frames 2, 2 extending in the longitudinal direction of the vehicle body from the front end portion to the rear end portion of the vehicle body, and the pair of left and right main frames 2, 2 faces from the front to the rear. First to fifth cross members 3 to 7 are arranged in this order. This type of frame structure is called a “ladder frame”.

  The pair of left and right main frames 2, 2 has a front portion 2a constituting a narrow portion having a relatively small interval, a rear portion 2b constituting a large portion having a relatively large interval, and the front portion 2a and the rear portion. The intermediate part 2c between 2b constitutes a widened part whose distance increases toward the rear.

  The front portion of the main frame 2, that is, the narrow portion 2 a is located in the engine room 8, and the engine 9 is mounted vertically in the engine room 8. A clutch unit 10 and a transmission unit 11 are disposed in series behind the longitudinal engine 9 in the longitudinal direction of the vehicle body, and the output of the transmission unit 11 is transmitted to the rear wheel 13 via the propeller shaft 12.

  The second cross member 4 is connected to the rear end portion of the intermediate widened portion 12 c of the main frame 2. The second cross member 4 is positioned in the middle portion of the cabin 14 in the front-rear direction, and the transmission unit 11 is fixed to the center portion of the second cross member 4 in the longitudinal direction via a mission mount member 15. In the figure, reference numeral 16 denotes an exhaust pipe. A catalyst container 17 and a main silencer 18 are interposed in the exhaust pipe 16, and these exhaust system parts are disposed between the left and right main frames 2 and 2. Yes. The catalyst container 17 is disposed between the second cross member 4 and the third cross member 5. Reference numeral 19 indicates a front wheel.

Japanese Utility Model Publication No. 58-60571 JP-A-8-175143

  The conventional truck frame structure has a certain resistance against the frontal collision by the left and right main frames. However, when an excessive collision load is applied, the small width portion 2a and the small width portion 2a obliquely outward in the vehicle width direction. In some cases, the bent portion between the first and second widened portions 2c is bent inward in the vehicle width direction and load absorption due to frame shaft compression is not effectively performed.

  An object of the present invention is to provide a vehicle body lower structure capable of effectively absorbing a collision load at the time of a frontal collision by frame shaft compression.

In order to achieve the above technical problem, the present invention
Left and right main frames that extend in the longitudinal direction of the vehicle body from the front end portion to the rear end portion of the vehicle, and are located on the inner side of the front wheel house and extend in parallel with each other, and extend rearward from the rear portion of the cabin and in parallel with each other A main frame having a large portion and an intermediate wide portion extending obliquely outward in the vehicle width direction from the small width portion toward the large portion, and an engine is mounted between the small width portions of the left and right main frames, In the vehicle body lower structure in which exhaust system parts extending from the engine are disposed between the left and right main frames,
An X-shaped cross member in a plan view extending in the vehicle width direction between the left and right main frames;
Left and right front end portions of the X-shaped cross member are connected to front portions of intermediate widened portions of the left and right main frames, and left and right rear end portions of the X-shaped cross member are connected to the left and right main frames. This is achieved by providing a vehicle body lower structure characterized in that it is connected to a rear portion of the intermediate widened portion.

  The X-shaped cross member typically includes a pair of skew members that extend obliquely when viewed between the left and right main frames in plan view and intersect each other between the left and right main frames, The pair of skew members are connected to each other in a state where they overlap each other at the center in the longitudinal direction. As another example of the X-shaped cross member, an X-shaped cross member in a plan view may be formed by connecting a member extending linearly to a central portion in the vehicle width direction in a plan view X-shaped.

  According to the present invention, since the left and right front end portions of the X-shaped cross member are connected to the small width portions of the left and right main frames, when a collision load is applied, the width between the small width portion and the intermediate wide width portion of the main frame is increased. The bent portion is supported by the skew member. From this, it is possible to prevent the bent portion between the small width portion and the intermediate wide portion of the main frame from bending inward in the vehicle width direction by the X-shaped cross member, and the collision load is reduced by the frame shaft compression. It can be absorbed effectively. In order to efficiently perform frame axis compression, the crossing angle of the X-shaped cross member, that is, as a typical example, for example, when this is constituted by a pair of skew members, the cross angle of the pair of skew members is There is a degree of freedom in design that can be selected.

  Further, by positioning the joining portion of the X-shaped cross member at the site of the conventional second cross member, the transmission case can be mounted on the joining portion instead of the conventional second cross member.

  In addition, as the exhaust gas regulations are tightened, the catalyst for purifying the exhaust gas tends to increase, and when the engine is a diesel engine, a considerably large DPF (diesel party) is used to purify the exhaust gas. It is necessary to install the curate filter) close to the engine. Conventionally, as described above, the catalyst is disposed between the third cross member and the fourth cross member. However, the catalyst container is installed in a triangular region formed on the side of the X-shaped cross member. Thus, not only can the catalyst container be installed closer to the engine than in the past, but the triangular area can be accommodated even if the catalyst container is large because the area of the triangle in plan view is quite wide. .

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a side view of a truck related to the embodiment. With reference to FIG. 1, a truck 100 has an engine room 102, a cabin 104, and a cargo box 106 in order from the front to the rear, and the engine room 102 and the cabin 104 are partitioned by a dash panel 108.

  FIG. 2 is a view of the track as viewed from below. Referring to FIGS. 1 and 2, engine 110 is mounted vertically in engine room 102 at the center in the vehicle width direction. That is, engine 110 is installed in engine room 102 such that a crankshaft (not shown) of engine 110 extends in the longitudinal direction of the vehicle body. A transmission unit 114 is connected to the rear end of the engine 110 in series in the longitudinal direction of the vehicle body via a clutch unit 112. A propeller shaft 116 extending rearward from the transmission unit 114 in the vehicle width direction is connected to a differential gear 118 at its rear end, and the driving force of the engine 110 is distributed to the left and right rear wheels 120 by the differential gear 118. . That is, this truck 100 employs a rear wheel drive system.

  With continued reference to FIG. 2, the track 100 has a ladder frame structure. That is, the frame structure of the truck 100 includes left and right main frames 122 and 122 having a rectangular closed cross section, and the main frame 122 having a rectangular closed cross section extends in the vehicle longitudinal direction from the front end portion to the rear end portion of the vehicle body. ing. The left and right main frames 122 and 122 have a front portion 122a constituting a narrow portion having a relatively small interval, a rear portion 122b constituting a large portion having a relatively large interval, and the front portion 122a and the rear portion 122b. The intermediate part 122c in between constitutes a widened part whose interval increases toward the rear.

  The frame structure of the truck 100 includes a plurality of cross members 124, 126, 128, 130 extending in the vehicle width direction between the left and right main frames 122, 122, and the conventional second cross member 4 (FIG. 2). ) In place of the X-shaped second cross member 132. That is, the first cross member 124 is disposed at the front end of the main frame 122, and the X-shaped first member extends from the front portion of the cabin 104, that is, from the front end portion of the intermediate wide portion 122c of the main frame 122 to the front end portion of the wide portion 122b. 2 cross members 132 are disposed, a third cross member 126 is disposed at the boundary between the cabin 104 and the cargo box 104, a fourth cross member 128 is disposed at the differential gear 118, and the main frame 122 A fifth cross member 130 is disposed at the rear end.

  The X-shaped second cross member 132 is composed of a pair of skew members 134 and 134 that are inclined and extended with respect to the longitudinal direction of the vehicle body. The pair of skew members 134 and 134 are intermediate portions in the longitudinal direction. Cross each other. The X-shaped second cross member 132 will be described later.

  In FIG. 2, reference numeral 138 indicates a fuel tank. The fuel tank 138 extends across the third cross member 126 and the fourth cross member 128 and is supported by the third and fourth cross members 126, 128. Yes.

  With continued reference to FIG. 2, the suspension mechanism of the rear wheel 120 includes a rigid axle 140, a leaf spring 142, and a shock absorber 144.

  The suspension mechanism of the front wheel 150 is a double wishbone system including an upper arm (not shown) and a lower arm 152. Reference numeral 154 denotes a front wheel lateral rod, and the front wheel lateral rod 154 is connected to the first cross member 124 and the lower arm 152. Reference numeral 156 in FIGS. 1 and 2 denotes a front wheel house.

  Further, referring to FIG. 2, as described above, the left and right main frames 122 have a front portion 122a extending in parallel with each other and a rear portion 122b extending in parallel with each other when viewed in a plan view, and between the front portions 122a. The interval is narrower than the interval of the rear portion 122b. In other words, the left and right front parts 122a and 122a constitute a narrow part, the rear parts 122b and 122b constitute a large part, and the intermediate wide part 122c between the front part 122a and the rear part 122b is a plan view. , Extending rearward and obliquely outward.

  The engine 110 is mounted on the front portion 122a of the main frame 122, that is, the narrow portion. An intermediate widened portion 122c extending obliquely outward and rearward from the small width portion 122a is located at the front portion of the cabin 104 from the rear end of the engine room 102. The intermediate widened portion 122c has a central portion in the longitudinal direction. A front cabin mount bracket 160 that extends outward in the vehicle width direction and obliquely forward is fixed, and the front cabin mount bracket 160 extends toward the front corner portion of the cabin 104, and is the front end portion of the side sill 162 of the cabin 104. From the first cabin side bracket 164 extending inward in the vehicle width direction and the first cabin mount member 166.

  The cabin 104 also has a second cabin side bracket 168 at the rear end corner portion. That is, the second cabin side bracket 168 extends inward in the vehicle width direction from the rear end portion of the side sill 162, and correspondingly to the front portion of the large portion 122 b of the main frame 122, the rear cabin mount A bracket 170 is provided outward in the vehicle width direction. The rear cabin mount bracket 170 and the second cabin side bracket 168 are fastened via a second cabin mount member 1172.

  The X-shaped second cross member 132 will be described with reference to FIGS. 6 and 7. The skew member 134 constituting the X-shaped second cross member 132 has a cross section as can be seen best from FIG. It is composed of a hat-shaped member. Each skew member 134 extends obliquely between the front portion of the intermediate widened portion 122c of one main frame 122 and a portion of the other main frame 122 behind it in plan view. The front end portion and the rear end portion of 134 are bolted to the lower surface of the main frame 122 having a rectangular closed cross section. As the fastening position of the rear end portion of the skew member 134, the front portion of the large portion 122b of the main frame 122 is employed in the embodiment. By changing the connecting portion of the rear end portion of the skew member 134 back and forth, the inclination angle of the skew member 134 can be arbitrarily set. Therefore, it is possible to prevent the bending portion between the narrow portion 122a and the intermediate wide portion 122b of the main frame 122 from bending inward in the vehicle width direction and to effectively generate the frame shaft compression against the frontal collision. , And a degree of freedom for setting an inclination angle of the skew member 134 suitable for this.

  The merging portion 180 where the pair of skew members 134 intersect each other is in a state where the pair of skew members 134 overlap each other and are connected to each other. The joining portion 180 of the pair of skew members 134 is positioned at the longitudinal position of the conventional second cross member (FIG. 9) indicated by the phantom line 4 in FIGS. 2 and 6. The transmission unit 114 is mounted via the mount member 182. Reference numeral 184 in FIG. 7 indicates a through hole that vertically penetrates the pair of skew members 134 and 134 in a state of being overlapped with each other, and a pair of skew members 134, The members 134 are connected to each other to form the merge portion 180, and the mission mount member 182 is fastened to the merge portion 180 using the bolts. In other words, the pair of skew members 134 and 134 are connected to each other using fasteners that fix the mission mount member 182 to the pair of skew members 134.

  Returning to FIG. 2, a catalyst container 194 is interposed in an exhaust pipe 148 extending backward from an exhaust manifold 190 on one side of the vertical engine 100, and a main silencer 196 is interposed downstream thereof. An exhaust system component including an exhaust pipe 148, a catalyst container 194 having a larger diameter than the exhaust pipe 148, and a main silencer 196 is disposed between the left and right main frames 122, 122. 200 in the lower region (FIG. 4) of the X-shaped second cross member 132, that is, a region of a triangle in plan view formed on the side of the pair of skew members 134, 134 that intersect each other. ing. The main silencer 196 is disposed in the lower region of the packing box 106.

  According to the embodiment of the present invention, when a collision load at the time of a frontal collision is applied, the bending portion between the small width portion 122a and the intermediate widening portion 122c of the main frame 122 is bent inward in the vehicle width direction. It can be prevented by the row member 134, and thereby, the collision load can be effectively absorbed by the frame axis compression. In addition, in order to effectively absorb the collision load, there is a degree of freedom in design that the inclination angle of the skew member 134 can be selected.

  Further, when the engine 110 is a diesel engine, a large PDF container needs to be installed as an exhaust system component for exhaust gas purification, but the plan view formed by a pair of skew members 134 and 134 intersecting each other. Since the triangular side region has a considerable size, a large catalyst container 194 can be provided. Further, since the catalyst container 194 can be brought closer to the engine 110 than in the past, the catalyst can be activated earlier when it is cold.

It is the perspective view which looked at the track of the example from the side. It is the figure which looked at the track of Drawing 1 from the lower part. It is sectional drawing cut | disconnected along the III-III line of FIG. It is sectional drawing cut | disconnected along the IV-IV line of FIG. FIG. 5 is a sectional view taken along line VV in FIG. 2. It is the expansion perspective view which extracted the part of a pair of skew member which mutually cross | intersects. It is an expansion perspective view of the confluence | merging part of a pair of skew member which mutually cross | intersects. It is the figure which looked at the conventional truck from the side. It is the figure which looked at the track of Drawing 8 from the lower part.

Explanation of symbols

100 truck 102 engine room 104 cabin 106 cargo box 110 engine (vertical installation)
112 Clutch unit 114 Transmission unit 122 Main frame 122a Front part of main frame (small width part)
122b Rear part of main frame (large part)
122c Intermediate widened portion 132 X-shaped second cross member 134 Skew member 150 Front wheel 156 Front wheel wheel house 180 Merging portion of skew member 182 Mission mount member 184 Through hole 194 Catalyst container

Claims (6)

Left and right main frames that extend in the longitudinal direction of the vehicle body from the front end portion to the rear end portion of the vehicle, and are located on the inner side of the front wheel house and extend in parallel with each other, and extend rearward from the rear portion of the cabin and in parallel with each other A main frame having a large portion and an intermediate wide portion extending obliquely outward in the vehicle width direction from the small width portion toward the large portion, and an engine is mounted between the small width portions of the left and right main frames, In the vehicle body lower structure in which exhaust system parts extending from the engine are disposed between the left and right main frames,
An X-shaped cross member in a plan view extending in the vehicle width direction between the left and right main frames;
Left and right front end portions of the X-shaped cross member are connected to front portions of intermediate widened portions of the left and right main frames, and left and right rear end portions of the X-shaped cross member are connected to the left and right main frames. A vehicle body lower structure characterized in that the vehicle body lower structure is connected to a rear portion of the front portion of the intermediate widened portion. The X-shaped cross member is composed of a pair of skew members extending obliquely when viewed between the left and right main frames and intersecting each other between the left and right main frames,
The vehicle body lower part structure according to claim 1, wherein the pair of skew members are connected to each other in a state in which the pair of skew members are vertically overlapped at a central portion in the longitudinal direction.   The vehicle body lower part structure according to claim 1, wherein left and right rear end portions of the X-shaped cross member are connected to the corresponding large portion of the main frame. The engine is a vertical engine;
The vehicle body lower part structure according to claim 1, wherein a transmission case connected to a rear portion of the longitudinal engine is mounted at a confluence portion in the center in the vehicle width direction of the X-shaped cross member. The transmission case is mounted at a junction where the pair of skew members intersect with each other via a mission mount member,
A connector for connecting the mission mount member to the joining portion of the matching skew members and a connector for connecting the pair of skew members in a state of being vertically stacked are common, and a common connector The vehicle body lower part structure according to claim 2, wherein the pair of skew members are connected to each other to form the merging portion and the mission mount member is connected to the merging portion.   An exhaust system component connected to the vertical engine and interposed in an exhaust pipe extending rearward and having a diameter larger than the exhaust pipe is a triangle in a plan view formed on a side portion of the X-shaped cross member. The vehicle body lower part structure according to claim 1 or 3, which is disposed in the region.

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