JP5704434B2 - Vehicle under-run protector mounting structure - Google Patents

Description

  The present invention relates to an attachment structure for an under-run protector disposed in front of or behind a body frame.

  When a vehicle with a low vehicle height (hereinafter referred to as a small vehicle) such as a passenger car collides with a vehicle with a high vehicle height such as a truck (hereinafter referred to as a large vehicle) or a rear-end collision, the small vehicle is located below the large vehicle. There is a risk of dive into. In order to prevent such an inconvenience, it is known that an underrun protector is disposed in the front part or rear part of a large vehicle. Such an underrun protector is firmly fixed to the vehicle body frame via a support member such as a bracket.

JP-A-9-263196

  By the way, when vibration from a drive system / braking system such as a brake judder occurs, the cab resonates or the vehicle body frame elastically resonates in a low frequency band. Since the underrun protector is fixed to the vehicle body frame, when the vehicle body frame elastically resonates at a low frequency, it moves following the vehicle body frame. For such inconvenience, it can be considered that a rubber mount is interposed between the under-run protector and the bracket and the under-run protector is used as a dynamic damper to prevent elastic resonance of the vehicle body frame.

  However, when using a commercially available rubber mount, even when a soft one is selected and used, the lowest resonance frequency of the underrun protector is about 45 Hz, which is generally about 6 Hz. It is much higher than the frequency, and it is difficult to make the underrun protector function as a dynamic damper.

  Therefore, an object of the present invention is to provide a vehicle under-run protector mounting structure that has a function as a dynamic damper without impairing the original function of the under-run protector.

  In order to achieve the above object, a vehicle under lamp protector mounting structure according to the present invention includes a vehicle body frame, an under lamp protector, a bracket, and an elastic member.

The underrun protector is disposed below the front part or below the rear part of the body frame and extends in the vehicle width direction. The bracket is supported so as to be swingable with respect to the vehicle body frame about a rotating shaft extending in the vehicle width direction. The bracket includes a protector mounting portion to which the underrun protector is mounted and a swing range limiting portion that limits a swingable range with respect to the vehicle body frame. The elastic member is interposed between the vehicle body frame and the swing range limiting portion, and is elastically deformed according to the swing of the bracket. The rotation shaft is disposed above the upper surface of the vehicle body frame, and the protector mounting portion is disposed below the lower surface of the vehicle body frame.

  In the above configuration, when the body frame elastically resonates in a low frequency band, the underrun protector and the bracket swing integrally with the body frame like a pendulum movement by elastic deformation of the elastic member. The under-run protector absorbs vibration due to elastic resonance of the vehicle body frame by swinging together with the bracket. That is, since the underrun protector swings like a pendulum motion with respect to the vehicle body frame, the resonance frequency can be set lower than when an elastic member is interposed between the underrun protector and the bracket. . Therefore, the resonance frequency of the underrun protector can be set to match or approach the resonance frequency of the vehicle body frame, and the underrun protector can function as a dynamic damper.

  In addition, when a load is input to the underrun protector at the time of a vehicle collision and the bracket swings (rotates) around the rotation axis beyond the elastic range of the elastic member, the swing range limiter causes the bracket to rotate. Limited and prevents movement of the underrun protector. Therefore, the function of preventing the underrun by the underrun protector is not impaired, and the original function of the underrun protector can be ensured.

  The bracket swing range limiting portion may include an upper plate portion disposed above the upper surface of the body frame and a lower plate portion disposed below the lower surface of the body frame. The elastic member includes a first rubber mount disposed between the upper surface of the vehicle body frame and the upper plate portion of the bracket; a second rubber mount disposed between the lower surface of the vehicle body frame and the lower plate portion of the bracket; You may have. The body frame is sandwiched between the upper plate portion and the lower plate portion of the bracket via the first rubber mount and the second rubber mount.

  In the above configuration, the vehicle body frame is sandwiched between the upper plate portion and the lower plate portion of the bracket via the first rubber mount and the second rubber mount, and the elastic support state of the bracket by the vehicle body frame is stabilized. . Therefore, the performance of the underrun protector as a dynamic damper can be improved.

  Further, since the vehicle body frame is sandwiched between the upper plate portion and the lower plate portion of the bracket, the rotational movement of the bracket when the load is input to the underrun protector is reliably restricted by the vehicle body frame. Therefore, it is possible to sufficiently ensure the function of preventing the under-run protector from getting in.

  The rotating shaft may be disposed above the protector mounting portion of the bracket, and the bracket may be connected to the body frame so as to be swingable in the front-rear direction.

  In the above configuration, since the swing center of the under-run protector is located above the protector mounting portion, compared to the case where the swing center of the under-run protector is set behind or in front of the protector mounting portion, The length can be shortened, and the underrun protector can be attached even when the installation space is narrow.

  According to the present invention, the underrun protector can be provided with a function as a dynamic damper without impairing the original function of the underrun protector.

It is a model side view of a cab overtrack provided with the underrun protector attachment structure concerning the present invention. It is a principal part expansion perspective view of an underlamp protector attachment structure. It is the side view which looked at FIG. 2 from the vehicle width direction inner side. FIG. 4 is a cross-sectional view taken along arrow IV-IV in FIG. 3. It is a schematic side view of a cab overtrack when the present invention is applied to a rear underrun protector.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the figure, FR indicates the front of the vehicle, UP in the figure indicates the upper side of the vehicle, and IN in the figure indicates the inner side in the vehicle width direction. Further, in the following description, the front-rear direction means the front-rear direction of the vehicle, and the left-right direction means the left-right direction in a state of facing the front of the vehicle.

  As shown in FIG. 1, a vehicle 1 according to the present embodiment is a cab-over type vehicle in which a cab 2 is generally positioned in front of an engine (not shown), and an under lamp protector is attached to the front portion of the vehicle 1. Structure 3 is provided. This under-run protector mounting structure 3 is provided symmetrically on the left and right of the vehicle 1 and supports a common front under-run protector (under-run protector) 5 on the left and right. Since the left and right under-run protector mounting structures 3 have substantially the same configuration, only the right side will be described below and the left side description will be omitted.

  As shown in FIGS. 2 to 4, the under-run protector mounting structure 3 is arranged on a chassis frame (vehicle body frame) 4 extending in the front-rear direction on both sides in the vehicle width direction and below the front portion of the chassis frame 4. A front under-run protector 5 extending in the vehicle width direction, a bracket 6 for supporting the front under-run protector 5 by the chassis frame 4, and a rotary shaft 13 that pivotally connects the bracket 6 to the chassis frame 4; A first rubber mount (elastic member) 7 and a second rubber mount (elastic member) 8 interposed between the chassis frame 4 and the bracket 6, and a support portion 9 interposed between the front underrun protector 5 and the bracket 6. And.

  The chassis frame 4 has a substantially U-shaped cross section including a side wall portion 10 that rises, and an upper wall portion 11 and a bottom wall portion 12 that extend oppositely from both ends of the side wall portion 10 in the vehicle width direction. Have A bracket mounting bearing 14 (see FIG. 3) for rotatably supporting the rotating shaft 13 is fixed to a predetermined position on the upper surface of the upper wall portion 11 with a bolt or the like. The shaft center of the rotating shaft 13 supported by the bearing 14 extends along the vehicle width direction.

  The front underrun protector 5 has a front protector piece 15 and a rear protector piece 16, both of which are made of thin steel plates and have a substantially U-shaped cross section. Is formed. The protector piece 15 includes a side wall portion 17, and an upper wall portion 18 and a bottom wall portion 19 that extend opposite to each other from the upper and lower ends of the side wall portion 17 to the rear side. The protector piece 16 has a side wall part 20, and an upper wall part 21 and a bottom wall part 22 that extend oppositely from the upper and lower ends of the side wall part 20 to the front side. In addition, a bolt insertion hole (not shown) for mounting a lower portion of the front under-run protector 5 into which a bolt (not shown) can be inserted is formed at a predetermined position of the bottom wall portion 22 of the protector piece 16. A nut (not shown) that is screwed to the bolt is fixed to the inner surface (upper surface) of 22 by welding or the like.

  The protector piece 15 and the protector piece 16 are joined together by welding or the like. Thereby, a closed cross section is formed between the protector piece 15 and the protector piece 16. Caps 25 are attached to both ends of the front underrun protector 5.

  The bracket 6 includes a first bracket 26 disposed below the chassis frame 4 and a second bracket 27 disposed above the first bracket 26 so as to extend laterally from above the chassis frame 4. The rotating shaft 13 is connected to the chassis frame 4. Hereinafter, the bracket 6 in a state of being connected to the chassis frame 4 by the rotating shaft 13 will be described.

  The first bracket 26 has a substantially box shape having a peripheral wall portion 28, a pair of side wall portions 29, 29, and a protector mounting portion 30. The peripheral wall portion 28 has a substantially V shape in which a belt-shaped metal plate is bent at an intermediate portion, and has a flat plate-like upper wall portion 28a extending forward from the V-shaped bent portion. The pair of side wall portions 29 and 29 are each a metal plate, are disposed inside the V shape of the peripheral wall portion 28, and are opposed to each other while being separated in the vehicle width direction (the width direction of the peripheral wall portion 28). The outer edges excluding the front edge of each side wall 29 are joined to the inner surface of the peripheral wall 28. The protector mounting portion 30 is a metal plate having an L-shaped cross section that bends forward, and is joined to the front end edges of the side wall portions 29 and 29.

  The second bracket 27 is formed by bending a metal plate punched into a predetermined shape, and includes a side plate portion 31, an upper plate portion (swing range limiting portion) 32, and a lower plate portion (swing range limit portion) 33. Is integrated. The side plate portion 31 stands up outside the chassis frame 4 in the vehicle width direction, and the upper plate portion 32 and the lower plate portion 33 extend opposite to each other in the vehicle width direction from both ends in the vertical direction of the side plate portion 31. . The distance in the height direction between the lower surface of the upper plate portion 32 and the upper surface of the lower plate portion 33 is the height of the chassis frame 4 (the distance in the height direction between the upper surface of the upper wall portion 11 and the lower surface of the bottom wall portion 12). Is set larger than. The lower plate portion 33 is joined to the upper wall portion 28a while being placed on the upper surface of the upper wall portion 28a of the first bracket 26. The length of the upper plate portion 32 in the front-rear direction is set shorter than that of the lower plate portion 33. The outer end of the rotating shaft 13 in the vehicle width direction is joined to the inner surface of the side plate portion 31 in the vicinity of the front of the upper plate portion 32, and the rotating shaft 13 is substantially parallel to the upper plate portion 32 and the side plate portion 31. Extends inward in the vehicle width direction.

  The bracket 6 is pivotably connected to the chassis frame 4 about the rotation shaft 13 by inserting the rotation shaft 13 through a bearing 14 fixed to the chassis frame 4. In this connected state, the upper plate portion 32 is disposed above the upper surface of the chassis frame 4 (the upper surface of the upper wall portion 11) and faces the upper surface of the upper wall portion 11, and the lower plate portion 33 is disposed on the chassis frame 4. It arrange | positions under the lower surface (lower surface of the lower wall part 12), and opposes the lower surface of the lower wall part 12. FIG. The upper plate portion 32 and the lower plate portion 33 limit the swingable range of the bracket 6 with respect to the chassis frame 4. The first rubber mount 7 is interposed between the upper plate portion 32 and the upper wall portion 11 so as to fill a gap between the lower surface of the upper plate portion 32 and the upper surface of the upper wall portion 11 of the chassis frame 4. 6 is elastically deformed in response to the rocking motion. The second rubber mount 8 is interposed between the lower plate portion 33 and the bottom wall portion 12 so as to fill a gap between the upper surface of the lower plate portion 33 and the lower surface of the bottom wall portion 12 of the chassis frame 4. 6 is elastically deformed in response to the rocking motion.

  The support portion 9 is a metal plate having a U-shaped cross section, and includes an upper plate portion 37 and a lower plate portion 38 that extend opposite to each other from the upper and lower ends of the side wall portion 36 toward the front side (front under lamp protector 5 side). And have. The inner surface shape of the support portion 9 has substantially the same shape as the outer surface shape of the protector piece 16 of the front underrun protector 5, and the side wall of the support portion 9 is assembled with the support portion 9 and the front underrun protector 5 assembled. The portion 36, the upper plate portion 37, and the lower plate portion 38 are in contact with the side wall portion 20, the upper wall portion 21, and the bottom wall portion 22 of the protector piece 16, respectively.

  A bolt insertion hole (not shown) for attaching the lower portion of the front underrun protector 5 is formed at a predetermined position of the lower plate portion 38 of the support portion 9. A support piece 39 is joined to the upper plate portion 37 of the support portion 9 by welding or the like. The support piece 39 is a metal plate having an L-shaped cross section, and extends upwardly from a bottom wall portion 40 that contacts the upper plate portion 37 of the support portion 9 and an end portion of the bottom wall portion 40 on the bracket 6 side. And a side wall 41. A bolt insertion hole 43 (see FIG. 2) for attaching the upper portion of the front underrun protector 5 is formed at a predetermined position of the side wall portion 41.

  The protector mounting portion 30 of the bracket 6 includes a side wall portion 44 and an extending portion 45 that bends and extends from the lower end of the side wall portion 44 toward the front side (front under lamp protector 5 side). In a state where the protector mounting portion 30 and the support portion 9 are assembled, the side wall portion 44 and the extension portion 45 of the protector mounting portion 30 abut against the side wall portion 36 and the lower plate portion 38 of the support portion 9, respectively.

  A bolt insertion hole (not shown) for attaching the lower part of the front underrun protector 5 is formed at a predetermined position of the extending part 45 of the protector attaching part 30. Further, a bolt insertion hole (not shown) for mounting the upper portion of the front underrun protector 5 is formed in the upper portion of the side wall portion 44 of the protector mounting portion 30.

  By inserting a bolt into the bolt insertion hole 43 of the side wall portion 41 of the support piece 39 and the extension portion 45 of the protector mounting portion 30 and screwing this bolt and nut (not shown), the front underrun protector 5 is inserted. Is fixed to the bracket 6. Further, a bolt is inserted into the extending portion 45 of the protector mounting portion 30, the lower plate portion 38 of the support portion 9, and the bolt insertion hole of the bottom wall portion 22 of the protector piece 16, and the bolt and the inner surface of the bottom wall portion 22 are inserted. The lower part of the front underrun protector 5 is fastened and fixed to the bracket 6 by screwing the fixed nut.

  According to the present embodiment, when the chassis frame 4 is elastically resonated (mainly longitudinal bending resonance) in a low frequency band (for example, about 6 Hz), the underrun protector 5 and the bracket 6 are provided with the first rubber mount 7 and the second rubber. By the elastic deformation of the mount 8, the mount 8 swings integrally with the chassis frame 4 in the front-rear direction like a pendulum movement. The under-run protector 5 swings together with the bracket 6 to absorb vibration caused by elastic resonance of the chassis frame 4.

  Thus, since the underrun protector 5 swings like a pendulum movement with respect to the chassis frame 4, the resonance frequency is higher than when an elastic member is interposed between the front underrun protector 5 and the bracket 6. Can be set low. Therefore, it is possible to set the resonance frequency of the under-run protector 5 so as to coincide with or approach the resonance frequency of the chassis frame 4, and the under-run protector 5 can function as a dynamic damper.

  In addition, since the chassis frame 4 is sandwiched between the upper plate portion 32 and the lower plate portion 33 of the second bracket 27, a rearward load is input to the front underrun protector 5 when the vehicle 1 collides. When the bracket 6 rotates rearward and upward about the rotation shaft 13 beyond the elastic range of the second rubber mount 8, the lower plate portion 33 of the second bracket 27 comes into contact with the chassis frame 4 from below and the bracket 6. Limit the rotational movement of. Thereby, the rearward movement of the front underrun protector 5 is reliably prevented. Therefore, the function of preventing the submergence by the front underrun protector 5 is not impaired, and the original function of the front underrun protector 5 can be sufficiently secured.

  Further, the chassis frame 4 is sandwiched between the upper plate portion 32 and the lower plate portion 33 of the second bracket 27 via the first rubber mount 7 and the second rubber mount 8, and the bracket by the chassis frame 4 is used. The elastic support state of 6 is stabilized. Therefore, the performance of the front underrun protector 5 as a dynamic damper can be improved.

  Furthermore, since the swing center of the front underrun protector 5 is located above the front underrun protector 5, the swing center of the front underrun protector 5 is set behind or in front of the front underrun protector 5. The length of the bracket 6 in the front-rear direction can be shortened, and the front underrun protector 5 can be mounted even when the mounting space is narrow.

  In the present embodiment, the underrun protector mounting structure 3 is applied to the front underrun protector 5 disposed in front of the vehicle 1, but as shown in FIG. 5, the rear of the vehicle (below the rear part of the body frame). It is also possible to apply to the rear underrun protector 50 arranged in the above. Further, the rotary shaft 13 may be disposed at a place other than the upper portion of the chassis frame 4, the upper plate portion 32 and the first mount rubber 7 are omitted, and the second mount rubber 8 is provided at a plurality of locations (for example, two locations on the front and rear sides). ). Further, the swing range limiting portion is not limited to the upper plate portion 32 and the lower plate portion 33, and may be any member that limits the swing range of the bracket 6 with respect to the chassis frame 4.

  As mentioned above, although the embodiment to which the invention made by the present inventor is applied has been described, the present invention is not limited by the discussion and the drawings that form part of the disclosure of the present invention according to this embodiment. That is, it is needless to say that other embodiments, examples, operation techniques, and the like made by those skilled in the art based on this embodiment are all included in the scope of the present invention.

1 Vehicle 3 Under-ramp protector mounting structure 4 Chassis frame (body frame)
5 Front underrun protector (underrun protector)
6 Bracket 7 1st rubber mount (elastic member)
8 Second rubber mount (elastic member)
13 Rotating shaft 14 Bearing 26 First bracket 27 Second bracket 30 Protector mounting portion 32 Upper plate portion (swing range limiting portion)
33 Upper plate (oscillation range limiter)
50 Rear underrun protector (underrun protector)

Claims (3)

Body frame,
An under-run protector that is disposed below the front or lower rear of the vehicle body frame and extends in the vehicle width direction;
A protector mounting portion that is supported swingably with respect to the vehicle body frame about a rotating shaft extending in the vehicle width direction, and a swing that limits a swingable range with respect to the vehicle body frame. A bracket having a range limiting portion;
An elastic member interposed between the vehicle body frame and the swing range limiting portion and elastically deforming according to the swing of the bracket ;
The rotating shaft is disposed above the upper surface of the body frame,
The under lamp protector mounting structure for a vehicle, wherein the protector mounting portion is disposed below a lower surface of the vehicle body frame . The vehicle under-lamp protector mounting structure according to claim 1,
The bracket swing range limiting portion has an upper plate portion disposed above the upper surface of the vehicle body frame, and a lower plate portion disposed below the lower surface of the vehicle body frame,
The elastic member includes a first rubber mount disposed between the upper surface of the vehicle body frame and the upper plate portion, and a second rubber mount disposed between the lower surface of the vehicle body frame and the lower plate portion. Have
The vehicle under-lamp protector mounting structure, wherein the vehicle body frame is sandwiched between an upper plate portion and a lower plate portion of the bracket via the first rubber mount and the second rubber mount. A vehicle under-lamp protector mounting structure according to claim 1 or 2,
The underrun protector mounting structure for a vehicle, wherein the rotating shaft is disposed above a protector mounting portion of the bracket, and the bracket is pivotably connected to the body frame in the front-rear direction.

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