JP5704435B2 - 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 underrun protector mounting structure according to the present invention includes a vehicle body frame, an underrun protector, a structure mounting bracket, a protector mounting 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 structure mounting bracket is fixed to the vehicle body frame for mounting a structure different from the underrun protector. The protector mounting bracket is coupled to the structure mounting bracket via a rotating shaft extending in the vehicle width direction, and is supported so as to be swingable with respect to the vehicle body frame about the rotating shaft. The protector mounting 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 protector mounting bracket. The swing range limiting portion of the protector mounting bracket has an upper plate portion disposed above the upper surface of the vehicle body frame. The rotating shaft is disposed below the lower surface of the body frame.

  In the above configuration, when the body frame elastically resonates in a low frequency band, the underrun protector and the protector mounting bracket swing integrally with the body frame like a pendulum movement by elastic deformation of the elastic member. The under-run protector absorbs vibrations due to elastic resonance of the vehicle body frame by swinging together with the protector mounting bracket. That is, since the underrun protector swings like a pendulum movement with respect to the body frame, the resonance frequency should be set lower than when an elastic member is interposed between the underrun protector and the protector mounting bracket. Can do. 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.

  Also, when a load is input to the underrun protector during a vehicle collision and the protector mounting bracket swings (rotates) around the rotation axis beyond the elastic range of the elastic member, the protector mounting bracket is moved by the swing range limiter. The rotational movement of the underrun protector is restricted and the movement of the underrun protector is prevented. 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.

  Further, since the protector mounting bracket is supported by a structure mounting bracket that is fixed to the vehicle body frame in order to mount a structure different from the under-run protector, the structure for supporting the protector mounting bracket is attached to the vehicle body frame. There is no need to provide a new one. Therefore, the under-run protector can be attached without changing the structure of the vehicle body frame and the layout of other parts.

  Further, the swing range limiting portion of the protector mounting bracket may have a lower plate portion disposed below the lower surface of the vehicle body frame. The elastic member is a first rubber mount disposed between the upper surface of the vehicle body frame and the upper plate portion of the protector mounting bracket, and a second rubber member disposed between the lower surface of the vehicle body frame and the lower plate portion of the protector mounting bracket. And a rubber mount. The vehicle body frame is sandwiched between the upper plate portion and the lower plate portion of the protector mounting 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 protector mounting bracket via the first rubber mount and the second rubber mount, and the protector mounting bracket is elastically supported by the vehicle body frame. The state is stable. Therefore, the performance of the underrun protector as a dynamic damper can be improved.

  In addition, since the body frame is sandwiched between the upper and lower plate parts of the protector bracket, the rotational movement of the protector mounting bracket is securely regulated by the body frame when a load is input to the underrun protector. Is done. Therefore, it is possible to sufficiently ensure the function of preventing the under-run protector from getting in.

  Further, the rotation shaft may be disposed behind or in front of the protector mounting portion of the protector mounting bracket, and the protector mounting bracket may be coupled to the body frame so as to be swingable in the vertical direction.

  In the above configuration, since the swing center of the underrun protector is located behind or in front of the protector mounting portion, the rotation axis and the rotation shaft are compared with the case where the swing center of the underrun protector is set above or below the protector mounting portion. The distance from the center of mass of the underrun protector and the distance between the rotating shaft and the elastic member can be set longer, and as a result, the frequency at which the underrun protector performs well as a dynamic damper is set to It becomes easy to set to a frequency range (for example, about 6 Hz) that matches or approaches the resonance frequency.

  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 underrun protector 5 extending in the vehicle width direction, a protector mounting bracket 6 for supporting the front underrun protector 5 by the chassis frame 4, and a leaf suspension (another structure) 9 are fixed to the chassis frame 4. Suspension mounting bracket (structure mounting bracket) 15, and a first rubber mount (elastic member) 7 and a second rubber mount (elastic member) 8 interposed between the chassis frame 4 and the protector mounting bracket 6. ing.

  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 suspension mounting bracket 15 is fixed to a predetermined position on the lower surface of the bottom wall portion 12 of the chassis frame 4. The suspension mounting bracket 15 includes an upper wall portion 40 that is fixed to the lower surface of the bottom wall portion 12 by welding or the like, and a pair of left and right side wall portions 41 that extend downward from both left and right ends of the upper wall portion 40. A rotation shaft support hole 43 into which the rotation shaft 13 can be inserted is formed in the side wall portion 41.

  The rotary shaft 13 includes a leaf suspension support portion 44 at the center, first male screw portions (not shown) formed on both sides (outside) of the leaf suspension support portion, and a bearing support portion 45 formed on the outside thereof. , And a second male screw portion 46 formed at the outer end portion on the outside. The leaf suspension support portion 44, the first male screw portion, the bearing support portion 45, and the second male screw portion 46 have the same axis (the axis of the rotary shaft 13). The screw portion 46 is formed to be narrower than the leaf suspension support portion 44 and the first male screw portion.

  A rotary shaft insertion hole 47 is formed at the front end of the leaf suspension 9. The front end portion of the leaf suspension 9 is inserted between the side wall portions 41 of the suspension mounting bracket 15, the rotation shaft 13 is inserted into the rotation shaft support hole 43 of the side wall portion 41 and the rotation shaft support hole 43 of the leaf suspension 9, and the side wall The rotary shaft 13 is fixedly supported by the suspension mounting bracket 15 and fastened to the front end portion of the leaf suspension 9 by screwing and tightening nuts 48 from the left and right to the left and right first male screw portions protruding from the portion 41, respectively. Is supported by the suspension support portion 44 of the rotating shaft 13. A spacer 49 is provided between the front end portion of the leaf suspension 9 and the side wall portion 41 of the suspension mounting bracket 15 to restrict the movement of the leaf suspension 9 in the left-right direction.

  The front underrun protector 5 is made of a thin steel plate and is formed in a rectangular closed cross section having a front wall portion 17, a rear wall portion 20, an upper wall portion 18, and a lower wall portion 19. A bolt insertion hole (not shown) through which a bolt (not shown) can be inserted is formed at a predetermined position of the rear wall portion 20, and a nut (not shown) that engages with the bolt is formed on the front surface (inner surface) of the rear wall portion 20. (Omitted) is fixed by welding or the like. Caps 25 are attached to both ends of the front underrun protector 5.

  The protector mounting bracket 6 includes a pair of left and right side plate portions 29, left and right protector mounting portions 30, an upper plate portion (swing range limiting portion) 32, and a lower plate portion (swing range limiting portion) 33. It is supported at a predetermined position by the frame 4. Hereinafter, the protector mounting bracket 6 in a state of being supported at a predetermined position will be described.

Left and right side plate portions 29 are disposed respectively in the vehicle width direction inside and outside of the chassis frame 4, to stand along the longitudinal direction. The side wall portion 29 includes a front elastic support portion 34 extending from below the chassis frame 4 to above the chassis frame 4, and a rear connecting support portion 35 extending rearward from the elastic support portion 34 below the chassis frame 4. And integrally.

  The left and right protector mounting portions 30 bend left and right from the lower front portions of the left and right elastic support portions 34 and extend in the vehicle width direction. A bolt insertion hole (not shown) is formed in the protector mounting portion 30. The rear surface of the rear wall portion 20 of the front underrun protector 5 is brought into contact with the front surface of the protector mounting portion 30, and bolts are inserted into the bolt insertion holes of the rear wall portion 20 and the protector mounting portion 34. The protector mounting bracket 6 is fastened and fixed to the front underrun protector 5 by screwing with a nut fixed to the inner surface of the front underrun protector.

  The upper plate portion 32 has both end edges in the vehicle width direction joined to upper end edges of the left and right elastic support portions 34 to connect the left and right elastic support portions 34. The lower plate portion 33 has both end edges in the vehicle width direction joined to intermediate portions of the inner side surfaces of the left and right elastic support portions 34 to connect the left and right elastic support portions 34. The upper plate portion 32 and the lower plate portion 33 face each other vertically, and 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 (upper wall portion 11) of the chassis frame 4. (The distance in the height direction between the upper surface of the bottom wall 12 and the lower surface of the bottom wall portion 12).

  A bearing housing hole 51 into which the bearing 50 is mounted is formed at the rear end portion of the connection support portion 35. The bearing 50 includes an outer ring body (not shown) that is fixed to the connection support portion 35 by welding or the like, and an inner ring body (not shown) that is disposed on the inner diameter portion of the outer ring and rotates relative to the outer ring. With the left and right bearing support portions 45 of the rotating shaft 13 inserted through the inner diameter portions 52 of the inner ring bodies of the left and right connection support portions 35, the left and right second male screw portions 46 protruding from the bearing 50 are respectively nuts from the left and right. The inner ring body is fastened and fixed to the rotary shaft 13 while allowing relative rotation with the outer ring body by being screwed and tightened. As a result, the protector mounting bracket 6 is connected to the chassis frame 4 so as to be swingable in the vertical direction about the rotation shaft 13.

  In this connected state, the upper plate portion 32 of the protector mounting bracket 6 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 The lower surface of the chassis frame 4 is disposed below the lower surface (the lower surface of the lower wall portion 12) and faces the lower surface of the lower wall portion 12. The upper plate portion 32 and the lower plate portion 33 limit the swingable range of the protector mounting 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. It is elastically deformed in response to the swinging of the mounting bracket 6. 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. It is elastically deformed in response to the swinging of the mounting bracket 6.

  According to this 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 protector mounting bracket 6 include the first rubber mount 7 and the first rubber mount 7. 2 The elastic deformation of the rubber mount 8 causes the chassis frame 4 to swing integrally up and down like a pendulum movement. The underrun protector 5 absorbs vibration caused by elastic resonance of the chassis frame 4 by swinging together with the protector mounting bracket 6.

  As described above, the underrun protector 5 swings like a pendulum movement with respect to the chassis frame 4, so that an elastic member is interposed between the front underrun protector 5 and the protector mounting bracket 6. The resonance frequency 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.

  Further, since the chassis frame 4 is sandwiched between the upper plate portion 32 and the lower plate portion 33 of the protector mounting bracket 6, a rearward load is input to the front underrun protector 5 when the vehicle 1 collides. When the protector mounting bracket 6 rotates and moves around the rotation shaft 13 beyond the elastic range of the first rubber mount 7 or the second rubber mount 8, the upper plate portion 32 comes into contact with the chassis frame 4 from above or below. The plate portion 33 comes into contact with the chassis frame 4 from below to limit the rotational movement of the protector mounting bracket 6. 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 protector mounting bracket 6 via the first rubber mount 7 and the second rubber mount 8, and the protector by the chassis frame 4 is placed. The elastic support state of the mounting bracket 6 is stabilized. Therefore, the performance of the front underrun protector 5 as a dynamic damper can be improved.

  The protector mounting bracket 6 is supported by a suspension mounting bracket 15 fixed to the chassis frame 4 for mounting the leaf suspension 9, and the leaf suspension 9 and the protector mounting bracket 6 are supported by a common rotating shaft 13. Therefore, it is not necessary to newly provide a structure or a rotating shaft for connecting the protector mounting bracket to the chassis frame 4. Therefore, the under-run protector 5 can be attached without changing the structure of the chassis frame 4 or the layout of other components.

  In addition, since the swing center of the front underrun protector 5 is disposed behind the protector mounting portion 30, the swing center of the front underrun protector 5 is set above or below the protector mounting portion 30. The distance between the rotation shaft 13 and the center of mass of the front underrun protector 5 and the distance between the rotation shaft 13 and the elastic member (the first rubber mount 7 and the second rubber mount 8) can be set longer. Thus, the frequency at which the front underrun protector 5 performs well as a dynamic damper can be easily set to a frequency range (for example, about 6 Hz) that matches or approaches the resonance frequency of the chassis frame 4.

  In addition, since the bearing 50 is interposed at the connecting portion between the protector mounting bracket 6 and the rotary shaft 13, loosening of the nuts 48 and 53 due to the swinging of the protector mounting bracket 6 can be reliably suppressed.

  Furthermore, it is possible to share parts among vehicles in which the relative positions of the chassis frame 4, the front underrun protector 5, and the suspension mounting bracket 15 are common.

  In the present embodiment, the under-run protector mounting structure 3 is applied to the front under-run protector 5 disposed in front of the vehicle 1, but as shown in FIG. It is also possible to apply to the rear underrun protector 60 arranged in the above. Further, the rotating shaft that supports the protector mounting bracket 6 in a swingable manner may be supported by a bracket that is fixed to the chassis frame 4 in order to mount a structure other than the leaf suspension 9. Further, the swing range limiting portion is not limited to the upper plate portion 32 and the lower plate portion 33, but may be any member that limits the swing range of the protector mounting 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 Protector mounting bracket 7 1st rubber mount (elastic member)
8 Second rubber mount (elastic member)
9 Leaf suspension (other structures)
13 Rotating shaft 15 Suspension mounting bracket (Structure mounting bracket)
26 1st bracket 27 2nd bracket 30 Protector mounting part 32 Upper plate part (swing range limiting part)
33 Upper plate (oscillation range limiter)
50 Bearing 60 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 structure mounting bracket fixed to the vehicle body frame for mounting a structure different from the underrun protector;
A protector mounting portion that is connected to the structure mounting bracket via a rotating shaft that extends in the vehicle width direction, is swingably supported with respect to the vehicle body frame around the rotating shaft, and to which the underrun protector is mounted And a protector mounting bracket having a swing range limiting portion that limits a swingable range with respect to the vehicle body frame,
An elastic member interposed between the vehicle body frame and the swing range limiting portion and elastically deforming in response to the swing of the protector mounting bracket ,
The swing range limiting portion of the protector mounting bracket has an upper plate portion disposed above the upper surface of the vehicle body frame,
The underrun protector mounting structure for a vehicle, wherein the rotating shaft is disposed below a lower surface of the body frame . The vehicle under-lamp protector mounting structure according to claim 1,
The swing range limiting portion of the protector mounting bracket has 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 body frame is sandwiched between an upper plate portion and a lower plate portion of the protector mounting bracket via the first rubber mount and the second rubber mount. Construction. A vehicle under-lamp protector mounting structure according to claim 1 or 2,
The rotating shaft is disposed behind or in front of a protector mounting portion of the protector mounting bracket, and connects the protector mounting bracket to the body frame so as to be swingable in a vertical direction. Protector mounting structure.

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