JP4341931B2 - Body frame structure for small vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle body frame structure capable of reducing weight and improving boarding / exiting performance in a small vehicle including an impact absorbing portion protruding forward of a vehicle body.
[0002]
[Prior art]
It is publicly known to provide such an impact absorbing portion, which is disposed at substantially the same height as the front wheel axle (for example, Japanese Utility Model Publication No. 7-8129, US Pat. No. 4,234,755, Japanese Utility Model Application Laid-Open No. 2-118596, 3-25193). Moreover, as an example of disposing at a position higher than the front wheel axle, there are JP-A-55-156768, JP-A-2-63978, JP-A-9-286354, and the like.
[0003]
[Problems to be solved by the invention]
By the way, although the structural example which provides an impact-absorbing part at the same height as the front wheel axle is often used for amusement vehicles such as go-carts, it is not suitable because the height of the impact-absorbing part is not suitable for general traffic vehicles. On the other hand, even if the shock absorbing part is made higher than the front wheel axle so as to be adapted to a general traffic vehicle, as shown in Japanese Patent Laid-Open No. 55-156768, the frame part provided with the shock absorbing part is offset with a large step up and down. If this is done, the impact load concentrates on this offset part, so that high strength and high rigidity reinforcement is required in this part, resulting in an increase in weight and an increase in cost. Japanese Patent Laid-Open No. 2-63978 also has the same problem because the shock absorbing portion is disposed in front of the dash panel, resulting in an increase in weight and cost.
[0004]
Further, in Japanese Patent Laid-Open No. 9-286354, the body frame is provided with a substantially quadrangular portion consisting of left and right side members and front and rear cross members, the shock absorbing portion is connected to the front cross member, and the shock load is transferred to the front side. The body frame is shown to escape from the cross member to the left and right side members, but in this case as well, the connection part between the shock absorbing part and the front cross member and the connection part between the front cross member and the left and right side members are shown. Due to the deviation, a large impact load is applied to each connecting portion, and as a result, a large amount of reinforcement is required for each connecting portion.
Therefore, in view of such problems, the present invention has an object to provide a vehicle body frame structure that enables further weight reduction and cost reduction and also improves boarding / exiting performance.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, a first invention relating to a body frame structure of a small vehicle according to the present application includes a main frame that supports a floor portion at the center, a front frame at the front, a rear frame at the rear, and a front frame. A front wheel, a rear frame supporting a rear wheel drive unit disposed behind the rear wheel, and an impact absorbing unit disposed so as to project forward from the front wheel through the front wheel axle, and In the vehicle body frame structure of a small vehicle constituted by a plurality of pipe-like members arranged in the front-rear direction for this shock absorbing portion,
The shock absorbing portion includes a pair of side bumper pipes arranged on the left and right sides, and the rear end portions of the side bumper pipes are connected to the left and right sides of the vehicle body by connecting the front frame and the rear frame, respectively. The side bumper pipes and the side frame pipes are connected so as to overlap each front end of the arranged side frame pipes, and the side bumper pipes and the side frame pipes are arranged so as to be inclined downward toward the rear of the vehicle body.
[0006]
A second invention is characterized in that, in the first invention, the side bumper pipe and the side frame pipe are arranged in a straight line in a side view.
[0007]
According to a third aspect, in the first aspect, the center line of the side frame pipe is shifted downward with respect to the straight line connecting the front end of the side bumper pipe and the rear end of the side frame pipe. It is characterized by.
[0008]
In a fourth aspect based on the first aspect, the center line of the side bumper pipe is set above the center line of the side bumper pipe with respect to the straight line connecting the front end of the side bumper pipe and the rear end of the side frame pipe. It is characterized by being arranged shifted downward.
[0009]
【The invention's effect】
According to the first aspect of the invention, the rear end portions of the left and right side bumper pipes constituting the shock absorbing portion are connected to the front end portions of the left and right side frame pipes, respectively, so that the shock absorbing portion is added. Part of the impact load is transmitted from the impact absorbing portion to the front frame, and the other portion is transmitted to the rear frame via the side frame pipe. For this reason, it is possible to disperse and transmit the impact load to the entire body frame in a wide range, and to absorb it efficiently. Moreover, since the left and right side frame pipes can directly receive the rear end portions of the left and right side bumper pipes constituting the shock absorbing portion in the length direction, the connection portion between the side frame pipe and the side bumper pipe In addition, conventional large-scale reinforcement becomes unnecessary. As a result, it is possible to reduce the weight and cost of the entire body frame. Moreover, by arranging the side bumper pipe and the side frame pipe obliquely downward toward the rear, the floor portion can be lowered even if the shock absorbing portion is disposed above the front wheel axle, and the boarding / exiting performance is improved. It becomes possible.
[0010]
According to the second aspect, since the side bumper pipe and the side frame pipe are arranged on the same straight line as viewed from the side, it is possible to efficiently absorb the impact load by the side frame pipe.
[0011]
According to the third invention, the floor portion can be further lowered by arranging the side frame pipe offset downward from the straight line connecting the front end of the side bumper pipe and the rear end of the side frame pipe. It can be expected to get on and off more easily.
[0012]
According to the fourth invention, the side bumper pipe is offset by offsetting the side bumper pipe upward and the side frame pipe downward with respect to the straight line connecting the front end of the side bumper pipe and the rear end of the side frame pipe. Therefore, the impact load can be absorbed efficiently.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The first embodiment will be described below with reference to the drawings. 1 is a side view of the vehicle body frame, FIG. 2 is a plan view thereof, FIG. 3 is an external side view of a small vehicle to which the vehicle body frame is applied, and FIG. 4 is a side view of a main skeleton part in the small vehicle.
[0014]
First, the overall structure of the vehicle will be described with reference to FIGS. This vehicle has a pair of left and right front wheels 1 and rear wheels 2 on the front and rear of the vehicle body, and is a single seat type small four-wheel vehicle. The rear wheel 2 is driven by a swing-type rear wheel drive unit 3. A floor panel 4 is provided at an intermediate portion between the front wheel 1 and the rear wheel 2, and a living space 5 is provided above the floor panel 4, and a single seat type seat 6 is provided at a rear portion in the living space 5.
[0015]
A rear pillar pipe 7 that protrudes rearwardly and convexly is provided on the back surface of the seat 6 so as to extend in the vertical direction. The upper end of the rear pipe 7 is connected to a screen 9 that rises obliquely from the front of the vehicle body via the roof panel 8. 5 is surrounded by an arch. The lower part of the screen 9 is connected to a front cover 10 that covers the front part of the vehicle body, and headlights 10 a are provided on the left and right sides of the front cover 10. A bar handle 11 is provided at the front of the living space 5 to steer the front wheel 1, and a lower portion of the bar handle 11 is covered with an inner panel 12. Reference numeral 13 denotes a rear trunk attached to the rear of the rear pillar pipe 7, and reference numeral 14 denotes an engine cover that covers the upper part of the swing type rear wheel drive unit 3.
[0016]
As shown in FIG. 4, the vehicle body frame 20 of the vehicle includes a main frame 21 that supports the floor panel 4, a front frame 22 provided on the front side thereof, a rear frame 23 provided on the rear side thereof, the front frame 22 and the rear frame. 23, a side frame pipe 24 provided as a pair on the left and right of the vehicle body, and an impact absorbing portion 25 provided in front of the front frame 22 at the front of the vehicle body.
[0017]
From the center of the front portion of the main frame 21, there is provided an arm portion 26 that rises obliquely forward, and the handle post 15 is rotatably supported at its upper end portion. A bar handle 11 is coupled to the upper end of the handle post 15.
[0018]
The front frame 22 is a member that is inclined obliquely upward, and a front suspension arm 16 is rotatably supported at a lower portion thereof. A front end of the front frame 22 is connected to a knuckle arm 17, and a front wheel axle 18 is connected to the knuckle arm 17. Is provided.
[0019]
The rear frame 23 is a member that rises obliquely rearward. The rear frame 23 supports the rear pillar pipe 7, and the front end of the swing-type rear wheel drive unit 3 is swingably supported by an engine pivot 19 provided at the lower end. ing.
[0020]
Next, the body frame structure will be described in more detail. As is apparent from FIGS. 1 and 2, the main frame 21, the front frame 22, and the rear frame 23 are each formed by an appropriate material and method such as aluminum casting, and the main frame 21 and the front frame 22 are fastened by bolts 27a from the left and right. The main frame 21 and the rear frame 23 are fastened by bolts 27b from the rear, and these are continuously integrated in the front-rear direction as a whole.
[0021]
The front frame 22 has a side coupling portion 28 projecting left and right at the front end portion, and the front end portion of the side frame pipe 24 is fitted into a recess formed on the side surface, and a bracket 29 is overlapped from the outside to bolt It is integrated by fastening at 30. The side frame pipe 24 is a pipe made of a metal material as appropriate.
[0022]
In addition, a central coupling portion 31 is provided at the center of the front end of the front frame 22, and the height thereof is higher than the left and right side coupling portions 28, and is provided at a position that protrudes most forward in the front frame, Cushion mounting portions 32 of the front suspension are provided in pairs on the left and right sides of the central coupling portion 31.
[0023]
The shock absorbing portion 25 includes a bumper central pipe 33, a pair of side bumper pipes 34 parallel to both sides thereof, and a bumper plate 35 that connects the front end portions thereof. The bumper center pipe 33 and the side bumper pipes 34 are metal square pipes as appropriate.
[0024]
Among them, the bumper central pipe 33 is disposed in the front-rear direction substantially horizontally passing above the height position of the front wheel axle 18, and the rear end portion thereof is fastened by the central coupling portion 31 of the front frame 22 and the bolt 36. Yes. The left and right side bumper pipes 34 are obliquely lowered rearward, and the respective rear end portions are fastened with bolts 37 to the front end portions of the side coupling portions 28 provided on the left and right sides of the front frame 22.
[0025]
As is apparent from FIG. 1, the side bumper pipe 34 and the side frame pipe 24 are linear in a side view, and each of them is a point P1 at the center of the front end of the side bumper pipe 34 and a center of the rear end of the side frame pipe 24. It overlaps on the entire center line L1 connecting the point P2. Further, when viewed along the direction of the entire center line L1, the rear end of the side bumper pipe 34 and the front end of the side frame pipe 24 overlap, that is, overlap in the cross section of the connecting portion (FIG. 6). And FIG. 8).
[0026]
The side frame pipe 24 passes above the position of the bolt 27, which is a connection point between the front end of the main frame 21 and the rear end (lower end) of the front frame 22, and projects to the left and right of the front end of the rear frame 23 at the rear end. It is attached to the side coupling part 38 formed in this way. The side coupling portion 38 has the same structure as the side coupling portion 28 of the front frame 22, and has a concave portion for fitting the side frame pipe 24 on the side surface thereof. The bracket 40 is overlapped from the outside and fastened with a bolt 41. It is supposed to be.
[0027]
Pillar mounting portions 42 are also provided on the left and right of the rear portion of the rear frame 23, and the rear pillar pipe 7 is coupled and integrated by bolts 44 via brackets 43 that are similarly applied from the rear. In the figure, reference numeral 45 is a front cushion, and 46 is a tie rod.
[0028]
Next, the operation of this embodiment will be described. In FIG. 1, when an impact load of F is applied to the impact absorbing portion 25 from the front, a part thereof transmits a partial impact load of f <b> 1 to the central coupling portion 31 of the front frame 22 through the bumper central pipe 33. The partial load f1 is transmitted from the front frame 22 to the main frame 21, and an opposite load f2 is generated on the main frame 21, so that it is received and absorbed by the main frame 21. At this time, an intermediate point C of the line connecting the bolts 36 and 27 in a side view becomes a fulcrum in the front frame 22 of the moment caused by the loads f1 and f2 in the opposite directions.
[0029]
Further, a partial load f3 is transmitted from the side bumper pipe 34 to the side frame pipe 24, and further transmitted from the side frame pipe 24 to the rear frame 23 to be absorbed. At this time, since the end portions of the side bumper pipe 34 and the side frame pipe 24 overlap each other at the connecting portion, the partial load f3 of the side bumper pipe 34 is directly transmitted to the side frame pipe 24. Moreover, the side bumper pipe 34 and the side frame pipe 24 are on the same straight line L1, and the side frame pipe 24 receives this partial load f3 in the length direction.
[0030]
Therefore, the side frame pipe 24 is sufficiently rigid with respect to the partial load f3, can receive the partial load f3 directly from the side bumper pipe 34, and the partial load f3 is further transmitted from the side frame pipe 24. It can be transmitted to the rear frame 23 and absorbed. Therefore, the connecting portion with the side bumper pipe 34 is large as in the prior art, and a reinforcing structure is not necessary.
[0031]
In addition, the impact load F is separated into f1 and f3, the partial load f1 is transmitted from the central pipe 33 to the front frame 22, and the partial load f3 is transmitted from the side bumper pipe 34 to the rear frame 23 via the side frame pipe 24. Is done. Accordingly, the reverse loads f1 and f2 applied to the front frame 22 are also reduced, and the rigidity required for the front frame 22 can be reduced accordingly. In addition, since the impact load can be efficiently distributed throughout the body frame, it is possible to absorb the impact throughout the body frame by avoiding the concentration of local loads, thus reducing the weight and cost of the entire body frame. Become.
[0032]
In addition, since the side bumper pipe 34 and the side frame pipe 24 are arranged to be inclined obliquely downward to the rear, the boarding / exiting ability can be improved even though the shock absorbing portion 25 is located higher than the front wheel axle 18.
[0033]
Next, a second embodiment will be described. In this embodiment, only the inclination of the side bumper pipe and the side frame pipe is changed, and the other portions are not changed from the previous embodiment, so only the changed portions will be described using the same reference numerals (described later). The same applies to the third embodiment).
[0034]
FIG. 5 is a side view showing a connecting portion between a side bumper pipe and a side frame pipe according to this embodiment, and FIG. 6 is a sectional view taken along line 5-5. In this embodiment, as is apparent from FIG. 5, the side frame pipe center line L2 connecting the center point P3 of the front end of the side frame pipe 24 and the point P2 of the rear end is offset downward from the overall center line L1. Has been.
[0035]
A center line L3 of the side bumper pipe 34 connects the front end point P1 and the rear end P4, and coincides with the entire center line L1. That is, in this embodiment, only the side frame pipe 24 is offset downward. However, as shown in FIG. 6, the rear end of the side bumper pipe 34 and the front end of the side frame pipe 24 are always kept overlapped by a lap allowance W in the direction along the center line L1.
[0036]
In this way, the effect of the previous embodiment in impact load transmission can be similarly expected, and the side frame pipe 24 side can be further lowered, so that further improvement in boarding / exiting performance can be expected.
[0037]
FIGS. 7 and 8 relate to the third embodiment. In this embodiment, the side bumper pipe 34 is offset upward with respect to the entire center line L1, and the side frame pipe 24 is offset downward. In this way, in addition to the effects of the second embodiment, the side bumper pipe 34 can be disposed more horizontally, so that the impact load can be transmitted more efficiently. However, even in this case, the wrap margin W of the side bumper pipe 34 and the side frame pipe 24 is maintained as shown in FIG.
[0038]
The present invention is not limited to the above embodiment, and various modifications and applications are possible within the principle of the invention. For example, in the third embodiment of FIG. It can also be made to coincide with the center line L1.
[Brief description of the drawings]
FIG. 1 is a side view of a body frame according to a first embodiment (FIGS. 1 to 4). FIG. 2 is a plan view thereof. FIG. 3 is an external side view of a small vehicle to which the body frame is applied. FIG. 5 is an enlarged side view of the main part according to the second embodiment. FIG. 6 is a sectional view taken along line 6-6. FIG. 7 is the same as FIG. 5 according to the third embodiment. [Fig. 8] Same as Fig. 6 [Explanation of symbols]
21: Main frame, 22: Front frame, 23: Rear frame 23, 24: Side frame pipe, 25: Shock absorber, 33: Bumper central pipe, 34: Side bumper pipe 34

Claims (4)

A main frame that supports the floor portion is provided in the center, a front frame is provided in front of the main frame, a rear frame is provided in the rear, a front wheel is supported by the front frame, and a rear wheel drive unit disposed behind the rear frame is provided. A small vehicle that includes a plurality of pipe-like members that are supported and provided with an impact absorbing portion that passes above the front axle and projects forward from the front wheel, and the impact absorbing portion is disposed in the front-rear direction. In the body frame structure of
The shock absorbing portion includes a pair of side bumper pipes arranged on the left and right sides, and the rear end portions of the side bumper pipes are connected to the left and right sides of the vehicle body by connecting the front frame and the rear frame, respectively. A small size characterized in that the side bumper pipes and the side frame pipes are connected so as to overlap each front end portion of the arranged side frame pipes, and the side bumper pipes and the side frame pipes are respectively inclined downward toward the rear of the vehicle body. Vehicle body frame structure. 2. The body frame structure for a small vehicle according to claim 1, wherein the side bumper pipe and the side frame pipe are arranged in a straight line in a side view. 2. The small vehicle according to claim 1, wherein a center line of the side frame pipe is shifted downward with respect to a straight line connecting the front end of the side bumper pipe and the rear end of the side frame pipe. Body frame structure. It is characterized in that the center line of the side bumper pipe is shifted upward and the center line of the side frame pipe is shifted downward with respect to the straight line connecting the front end of the side bumper pipe and the rear end of the side frame pipe. A body frame structure for a small vehicle according to claim 1.

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