JPH0546556Y2 - - Google Patents

Description

[Detailed explanation of the invention] A. Purpose of the invention (1) Industrial application field The present invention is intended for use in vehicles mainly used for driving on rough terrain, and in particular, a main tube that slopes rearward and downward from the support of the steering shaft, and this invention. A frame having a seat rail extending rearward from the main tube substantially horizontally, an engine supported by the frame below the main tube, a fuel tank installed on the main tube, and a straddle installed on the seat rail. The present invention relates to a straddle-type vehicle equipped with a seat-type seat.

(2) Conventional technology Conventionally, in such saddle type vehicles, in order to reduce the filtration burden on the air cleaner, one end of the air intake pipe was opened as an outside air intake in the upper front of the vehicle body where there was less dust, and the other end was opened as an outside air intake port. It is known to connect to the inlet pipe of an air cleaner (for example, see Japanese Utility Model Application Publication No. 129690/1983).

(3) Problems to be solved by the invention The conventional structure described above requires a long air introduction pipe dedicated to the air cleaner, and the air introduction pipe is made of a flexible pipe such as a synthetic resin pipe. Since it does not have a support function for the air cleaner, a special support structure is required to support the air cleaner on the frame, and the overall structure is complicated.

In order to solve this problem, for example, as disclosed in Japanese Utility Model Application No. 59-167728, the rear end of the main tube of the frame whose front end is open to the atmosphere is connected to an air cleaner, and the main tube is connected to the air cleaner. It has already been proposed that the rear end of the main tube is connected to both the left and right sides of the air cleaner, so that the rear end of the main tube is connected to both the left and right sides of the air cleaner. The problem is that the intake passage is bent significantly, increasing intake resistance.Also, since the air cleaner is installed relatively close to the rear of the engine, if a suspension spring for the rear wheels is placed there, the air cleaner will be attached to the rear wheel suspension spring. There is also the problem that the effective volume has to be reduced in order to avoid interference with the spring (see, for example, FIG. 1 of Japanese Patent Application Laid-Open No. 61-215185).

The present invention has been proposed in view of the above, and aims to provide a straddle-type vehicle that can solve all of the above-mentioned conventional problems.

B. Structure of the device (1) Means for solving the problem In order to achieve the above object, the present invention includes a pair of left and right main tubes that extend backward and downward from the support of the steering shaft, and a pair of left and right main tubes. a frame having a pair of left and right seat rails extending substantially horizontally rearward from each other; an engine supported by the frame below a main tube; a fuel tank installed on the main tube; and a fuel tank installed on the seat rails. In a straddle-type vehicle equipped with a straddle-type seat, the front end of the main tube is open to the atmosphere, and the rear end extends rearward than the front end of the corresponding seat rail, and both of the extending portions and the A rear wheel suspension spring disposed behind the engine is supported on a cross member that connects both seat rails, and a rear wheel suspension spring disposed behind the suspension spring is supported on the front surface of an air cleaner disposed behind the suspension spring. A pair of left and right inlet tubes into which the rear ends are respectively fitted are protruded, and an intake pipe extending toward the engine from the front surface of the air cleaner passes between the suspension of the cross member and the lower surface of the seat. It is a feature.

(2) Effect According to the above configuration, even if the air cleaner is made larger, it can be easily placed in the vehicle body space behind the rear wheel suspension spring while avoiding interference with the rear wheel suspension spring. Even if the air cleaner is separated from the front of the vehicle, the main tube functions as an air introduction pipe, allowing clean air from the upper front of the vehicle with less dust to be introduced into the air cleaner. Furthermore, since the rear end of each main tube is fitted into the inlet tube on the front of the air cleaner, the intake passage leading from the inside of the main tube to the inside of the air cleaner does not have to be bent significantly on the way, which reduces intake resistance and The rear end of the tube can support the front end of the air cleaner.

Further, since the rear extending portions of the left and right main tubes and the left and right seat rails mutually reinforce each other via the cross member, the support rigidity for the suspension springs as a whole is greatly improved. Moreover, since the intake pipe extending from the front of the air cleaner toward the engine passes between the suspension spring support part of the cross member and the underside of the seat, even if the suspension spring is slightly displaced due to the vertical movement of the rear wheel, it will interfere with the spring. The intake pipe can be accurately routed in the vehicle body space above the spring and below the seat without causing any damage.

(3) Embodiment Hereinafter, an embodiment of the present invention will be explained with reference to the drawings. First, in FIGS. 1 and 2, a buggy vehicle 1 for driving on rough terrain has a pair of left and right front wheels on the front and rear parts of a frame 2, respectively. 3, 3 and rear wheels 4, 4
In addition, a fuel tank 5 and a straddle-type seat 6 are disposed on the upper part of the frame 2 in the front and rear to form a straddle-type structure.

The frame 2 includes a pair of left and right prismatic cylindrical main tubes 7, 7 that slope gently downward at the rear, and a pair of left and right tubes that extend from the lower surfaces of the front ends of these main tubes 7, 7 at a steep slope downward. front tubes 8, 8, a pair of left and right down tubes 9, 9 extending rearward at a steep slope from the upper end rear surface of these front tubes 8, 8, and extending downward from the rear of the main tubes 7, 7. A pair of left and right center tubes 10, 10, main tube 7,
A pair of left and right seat rails 11, 11 extending rearward approximately horizontally from the rear intermediate portion of the seat rails 11, 11, the rear ends of these seat rails 11, 11, and the center tube 1.
A pair of left and right stays 12, 12 connecting the middle portions of the center tubes 10, 10, left and right stays connecting the lower ends of the center tubes 10, 10 and the lower ends of the down tubes 9, 9, and extending forward from the down tubes 9, 9. The main elements are a pair of main lower tubes 13, 13, and a pair of left and right sub lower tubes 14, 14 that connect the down tubes 9, 9 and the front tubes 8, 8 above these main lower tubes 13, 13, The front ends of the main channels 7, 7 are connected to each other via a box-shaped gusset 15, and the rear ends of the seat rails 11, 11 are connected to each other via a cross member 16. Main lower tube 1
The front ends of sub-tubes 3 and 13 are connected to each other via a cross member 17, and the front ends of sub-roa tubes 14 and 14 are connected to each other via a cross member 18.

A bearing 20 for supporting a steering shaft 19 for the front wheels 3, 3 is provided on the front surface of the gusset 15,
A rod-shaped steering handle 21 is attached to the upper end of the steering shaft 19.

The main tubes 7, 7, down tubes 9, 9, main lower tubes 13, 13, and center tubes 10, 10 constitute a pair of left and right cradle structures 22, 22, between which an engine 23 with a transmission is installed. will be placed. The crankcase 24 of this engine 23 includes down tubes 9, 9 and main lower tubes 13, 13.
And bolts 29 are attached to brackets 26, 27, 28 that protrude from the center tubes 10, 10, respectively.
It is fixed in place. In this way, the engine 23 is supported by both cradle structures 22, 22 and connects both 22, 22 to each other. At this time, the left and right main tubes 7, 7 are disposed on both left and right sides of the cylinder head 25 of the engine 23 so as to sandwich the cylinder head 25 therebetween. The power of this engine 23 is transmitted to a common axle 40 of both rear wheels 4, 4 via a chain drive device 39.

A carburetor 30 is connected to the back of the cylinder head 25 of the engine 23, and an exhaust pipe 31 is connected to the front thereof.Furthermore, an air cleaner 33 is connected to the carburetor 30 via an intake pipe 32, and an exhaust pipe 3 is connected to the carburetor 30 via an intake pipe 32.
1 is connected to a muffler 34, respectively.

The fuel tank 5 has a main tube 7, which covers the engine 23 and the carburetor 30 from above.
The seat 6, which is connected to the rear end of the fuel tank 5, is removably mounted on the seat rails 11, 11, respectively. The air cleaner 33 is disposed within the frame 2 directly below the seat 6, and a stay 12 is provided on one side of the air cleaner 33.
The muffler 34 is disposed with the muffler 34 sandwiched therebetween.

Brackets 35, 35 are protruded from the lower front surfaces of the center tubes 10, 10, and a rear fork 36, which supports the rear wheels 4, 4 at the rear end thereof, is pivotably supported 37 to be vertically swingable. A hydraulic rear damper 38 is provided between the rear fork 36 and the frame 2, behind the engine 23 and in front of the air cleaner 33, for damping the vertical swing of the rear fork 36. It has a built-in suspension spring S that springs downward. A structure for attaching the rear damper 38 to the frame 2 will be described later.

Outside air from the upper front of the vehicle 1 is introduced into the air cleaner 33 through the left and right main tubes 7, 7 and the gusset 15.

That is, as shown in FIGS. 1 to 4, an outside air intake box 41 with open front and rear ends is provided on the lower surface of the gusset 15, and this outside air intake box 4
A large-diameter through hole 42 communicating with 1 is bored. Further, through holes 43, 43 for communicating the gusset 15 with the left and right main tubes 7, 7 are bored in the side walls of the main tubes 7, 7. On the other hand, Figures 5 and 6
As shown in the figure, connecting tubes 44, 44 having a circular cross section are bulged at the rear ends of the main tubes 7, 7.
These connecting cylinders 44, 44 are connected to the air cleaner 3.
Elastic seal cylinders 47, 4 are installed in a pair of left and right inlet cylinders 46, 46 protruding from the front surface of the cleaner case 45 of No. 3.
7 and are tightly fitted into each other.

The elastic seal cylinder 47 also fits into the outer peripheral surfaces of the connecting cylinder 44 and the inlet cylinder 46 outside of the fitting portion thereof, and is tightened by bands 48 and 49.
In this way, the front end of the cleaner case 45 is elastically supported by the left and right main tubes 7, 7.

On the other hand, in order to support the rear end of the cleaner case 45, a support pin 50 is provided protruding from the back surface of the cleaner case 45, and a bracket 52 that supports the support pin 50 via an elastic bushing 51 is attached to the cross member 1.
6 with bolts 53 and nuts 54.

In addition, an outlet pipe 5 is provided on the front of the cleaner case 45.
The upstream end of the intake pipe 32 is fitted onto the outer periphery of the outlet tube 55, and a tightening band 56 is attached to the outer periphery of the outlet tube 55.

The outlet tube 55 also protrudes inward of the cleaner case 45, and a cleaner element 57 is attached to the inwardly protruding end thereof.

The top surface of the cleaner case 45 is open,
A lid plate 58 that closes this open surface has a plurality of locking members 5
9, 59... are locked to the cleaner case 45. Therefore, when attaching and detaching the cleaner element 57, first the seat 6 is attached to the seat rails 11, 11.
The cleaner element 57 can be easily attached and detached by removing it from the cover plate 58 and then opening the cover plate 58.

7 and 8 show the mounting structure of the rear damper 38 to the frame 2. FIG. The extending portions 7r, 7r of the main tubes 7, 7 extending rearward from the front ends of the seat rails, and the seat rails 11, 11 located above the extending portions 7r, 7r have central portions curved inward of the frame 2. A pair of left and right brackets 60,60
Both ends of the brackets 60, 60 are welded to each other, and bosses 61, 61' are welded to the center portions of these brackets 60, 60, respectively. A centerpiece 62 for attaching the upper end of the rear damper 38 is disposed between the bosses 61, 61', and the bosses 61, 61' are connected to each other by bolts 63 that penetrate and support the centerpiece 62. The brackets 60, 60, the boss 6
1, 61' and the bolt 63 cooperate with each other to constitute a cross member C of the present invention that connects the extending portions 7r, 7r of the main tubes 7, 7 and both seat rails 11, 11. There is.

Next, the operation of this embodiment will be described.

While the buggy vehicle 1 is running, a part of the air passing through the outside air intake box 41 flows into the gusset 15 through the through hole 42, and is further divided into the left and right main tubes 7 through the through holes 43, 43, and then into the inlet tube. 46, 46 into the cleaner case 45 of the air cleaner 33, and after being filtered by the cleaner element 57, the outlet pipe 55
The mixture is guided to the carburetor 30 through the intake pipe 32, and is inhaled into the engine 23 as an air-fuel mixture.

In this way, the intake air of the engine 23 is transferred to the outside air intake box 41, the gusset 15, the main tube 7,
Since relatively clean air can be introduced into the air cleaner 33 from the upper front surface of the buggy vehicle 1 where there is less dust using the air filter 7, the filtration load on the air cleaner 33 is reduced.

In addition, the front and rear ends of the outside air intake box 41 are open, allowing the wind to pass through, so dirt, snow, etc. that enter the outside air intake box 41 are blown backward by the wind while the outside air is passing through. There is no accumulation in the intake box 41.

Further, since the pair of main tubes 7, 7 used as air introduction pipes have a small overall intake resistance, they can contribute to improving the output of the engine 23.

Furthermore, since the pair of main tubes 7, 7 are arranged to sandwich the cylinder head 25 of the engine 23 from the left and right sides, the fuel tank 5 installed on these main tubes 7, 7 does not interfere with the main tubes 7, 7. It is possible to arrange the fuel tank 5 as close as possible to the engine 23 without being affected by the engine 23, and the position of the fuel tank 5 is lowered accordingly, thereby lowering the center of gravity of the vehicle.

Furthermore, since the inlet cylinders 46, 46 of the air cleaner 33 are fitted to the rear ends of the main tubes 7, 7 via elastic seal cylinders 47, 47, the air cleaner 33 is elastically supported by the main tubes 7, 7. Therefore, the support structure of the air cleaner 33 is simplified.

C. Effects of the invention As described above, according to the invention, the rear ends of the pair of left and right main tubes with open front ends are extended rearward than the front ends of the corresponding seat rails, and the rear ends of both extensions are fitted. The pair of left and right inlet tubes that are used to connect the air cleaner are protruded from the front of the air cleaner, which is located further back than the rear wheel suspension spring behind the engine. It can be easily placed in the car body space behind the spring while avoiding interference, and even if the air cleaner is separated from the front of the car body due to such placement, the main tube can perform the function of an air introduction pipe. Clean air from the upper front part of the vehicle body with less dust can be introduced into the air cleaner, and the intake passage that passes through the main tube to the air cleaner does not have to be bent significantly midway, which contributes to reducing intake resistance. Moreover, the main tube can also be used as a support means for the front end of the air cleaner, contributing to the simplification of the support structure of the air cleaner.

In addition, since the rear wheel suspension spring is supported on the cross member that connects the left and right main tube extensions and the left and right seat rails, both main tube extensions and both seat rails can be connected to each other via the cross member. By reinforcing each other, the support rigidity for the suspension spring as a whole can be greatly increased. Moreover, since the intake pipe extending from the front of the air cleaner and heading toward the engine is passed between the cross member and the bottom surface of the seat, even if the suspension spring is slightly displaced due to the vertical movement of the rear wheel, the intake pipe will not be connected to the spring. It is possible to accurately route the intake pipe in the vehicle body space above the spring and below the seat without interfering with the air intake pipe, making effective use of the space, and avoiding contact with other objects in the intake pipe as much as possible. can.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a side view of a four-wheeled buggy, Fig. 2 is a plan view thereof,
Figure 3 is an enlarged sectional view taken along the - line in Figure 2, Figure 4 is a sectional view taken along the - line in Figure 3, and Figure 5 is an enlarged sectional view taken along the - line in Figure 1.
6 is a partially longitudinal sectional plan view of FIG. 5, FIG. 7 is an enlarged side view of the rear damper and its surroundings of FIG. 1, and FIG. 8 is a sectional view taken along the line -- of FIG. 7. C...Cross member, S...Suspension spring, 1...Four-wheel buggy vehicle as a straddle type vehicle, 2...Frame, 5...Fuel tank, 6...Seat, 7...Main tube, 7r... ...Extending portion, 23...Engine, 32...Intake pipe, 11...Seat rail, 3
3...Air cleaner, 46...Inlet tube.

Claims (1)

[Scope of utility model registration request] a pair of left and right main tubes 7 extending rearward and downward from the support portion of the steering shaft 19;
A frame 2 has a pair of left and right seat rails 11 extending rearward from the main tube 7 substantially horizontally, an engine 23 supported by the frame 2 below the main tube 7, and an engine 23 installed on the main tube 7. In a straddle-type vehicle equipped with a fuel tank 5 and a straddle-type seat 6 installed on a seat rail 11, the front end of each main tube 7 is open to the atmosphere, and the rear end is connected to the corresponding seat rail 11. Extends to the rear of the front end of the
A rear wheel suspension spring S disposed at the rear of the engine 23 is supported on the cross member C that connects both the extending portions 7r and the seat rails 11. A pair of left and right inlet tubes 46 into which the rear ends of both the extension portions 7r are fitted are protruded from the front surface of the air cleaner 33 provided,
A straddle-type vehicle characterized in that an intake pipe 32 extends from the front surface of the air cleaner 33 toward the engine 23 through between the cross member C and the lower surface of the seat 6.