JPH11301232A - Low-built double cab vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-built double cab vehicle excellent in elevating performance, comfortability and off-road travel performance. SOLUTION: A front frame 2a of smaller ground clearance than that of a frame 2 is connected by meas of a connecting member to a front end which is in front of a front axle 11 of the frame 2. A cab 1 is mounted on the front frame 2a, and hydraulic suspensions FS and RS are mounted to front and rear axles 11 and 12, respectively, so as to support a vehicle T. Accordingly, a floor surface 8 can be lowered, and for example, when elevating performance is required, the vehicle is lowered and in the case of off-road traveling, the vehicle height is increased by reducing or extending the hydraulic suspensions FS and RS as the occasion demands, to thereby improve travel performance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ladder-type frame supported above a front axle and a rear axle via a suspension, and a cab mounted on the frame.
The present invention relates to a low-floor type double cab vehicle which is improved in elevating and lowering properties, indoor living property and running on uneven terrain.

[0002]

2. Description of the Related Art In a conventional low-floor type double cab vehicle used for a fire truck such as a ladder truck, a water pump truck, a rescue work vehicle, etc., as shown in FIG. It was mounted on the front end of a straight frame 32. Therefore, the height of the floor of the cab 21 is determined by the height of the ground to the upper surface of the frame 32, and the height of the ground to the floor of the cab 21 determines the elevating property almost as it is.

The ground clearance up to the upper surface of the frame 32 is determined by the vertical action dimensions of the leaf spring FS used for the front axle suspension and the parent-child spring RS used for the rear axle suspension shown in FIGS. Front and rear tires W
It is determined by the ground clearance of the front and rear axles FA and RA, which can be determined by the sizes of F and WR.

[0004] Under such a great limitation of the suspension, some efforts have been made to lower the floor height of the cab 21 floor, but as a result, even if the floor surface related to the elevating property is lowered, various floors are required. Due to the surface projections, the entire floor surface is not flat and mobility and livability in the room are impaired.

The above-mentioned height above the floor and flatness of the floor surface have been particularly problematic for fire trucks and the like that require agile indoor operation and aggressive lifting and lowering in the event of a fire emergency.

In order to reduce the ground height of the cab 21, there is a method of lowering the height of the engine. However, a significant effect cannot be obtained due to the above-mentioned limitation of the suspension structure.

As shown in FIG. 15, the proximity of the vehicle to the target is determined by the front overhang FOH, which is the horizontal distance between the ground point of the front wheel WF and the lower surface of the front end of the vehicle, and the ground at the front overhang FOH. And high h. That is, it is possible to get over the obstacle S up to the height h, and the approach to the slope is determined by the height h and the approach angle α that can be obtained by the front overhang FOH. In FIG. 15, in the case of the long cab 21D, the front overhang FOH becomes large, and the approach angle becomes β, so that the approachability to the slope is deteriorated.

As described above, lowering the height of the cab floor surface to improve the ascending / descending property on the one hand has an incompatible relationship of impairing the approachability of the vehicle on the other hand.

Japanese Unexamined Patent Publication No. 5-62272 discloses a technique of disposing the engine position behind the front axle. However, this method alone has little effect due to the restriction of the frame minimum ground height by the suspension, Also,
Improving the approach angle has no direct effect.

[0010]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above-mentioned drawbacks of the prior art, and has good liftability.
It is an object of the present invention to provide a low-floor-type double cab vehicle with good livability and good approach.

[0011]

A low-floor type double cab vehicle according to the present invention comprises a ladder-type frame supported above a front axle and a rear axle via a suspension, and a cab mounted on the frame. And a front frame lower than the upper surface of the frame is connected to a front end of the frame in front of a front axle via a connecting member, and the cab is connected to the front frame. And the suspension is constituted by a fluid suspension.

According to the low-floor type double cab vehicle of the present invention configured as described above, the front frame having a low ground height is connected to the front end of the frame by the connecting member, and the cab is mounted on the front frame. Therefore, the cab floor is lowered so that the cab can be raised and lowered easily.
By making the floor flat, it is possible to improve the livability and operability in the room. If the cab is a double cab, the floor height of the front and rear seats can be made the same, and the traffic of the front and rear seats becomes easy.

Further, since the suspension is a fluid suspension, the height of the vehicle can be freely changed. For example, when the vehicle is going up and down, the vehicle height is lowered to improve the ascending and descending performance. Can be. As described above, the elevating property and the running property at the irregular site can be improved at the same time.

The fluid suspension of the low-floor double cab of the present invention is preferably a hydraulic cylinder. As a result, the vehicle height can be set with high accuracy, the reliability of maintaining the vehicle height for a long period of time is high, the maintenance is simple, and the vehicle is lightweight and small, and can be easily mounted on a conventional vehicle.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4, a low-floor double cab vehicle T includes front and rear axles 11 and 12 and front and rear axles 1.
Front fluid suspension FS mounted above 1 and 12
The ladder-type frame 2 is supported by a rear fluid suspension RS, and the cab 1 is mounted on the front of the ladder-type frame 2. Here, FIG.
Shows a ladder fire truck in which a ladder is mounted on a low-floor type double vehicle T.

The front axle 11 is a driven shaft in this case, and the front and rear portions of the frame 2 are supported from below by a fluid suspension FS, and the rear axle 12 is a drive shaft by a fluid suspension RS.

The ladder type frame 2 is formed so as to be substantially flat from the rear end to the front axle 11 and slightly forward. Referring to the side view in FIG. 3 and the top view in FIG. 4, the front frame 2 a is joined by the joining member 15 slightly forward of the front axle 11.

The front frame 2a is formed so that the cab 1 is mounted at a ground height Hf lower than the ground height Hm of the frame 2. The coupling member 15 includes a terminal plate 15a and a support plate 15b, and the terminal plate 1 is attached to the front end 2b of the frame 2.
At 5a, for example, the front frame 2a is welded to the terminal plate 15a via the support plate 15b. Thus, the connecting member 15 is
Front frame 2a offset in the height direction above
Is formed flat up to the tip of the vehicle. In addition,
Frame 2 and front frame 2 by connecting member 15a
The method of coupling with a is not based on welding, and may be, for example, bolt coupling or fitting coupling.

As described above, the separate front frame 2
By connecting a to the frame 2, it is possible to solve the difficulty of significantly reducing the ground clearance at the front end only by press forming the frame 2.

The cab 1 is shown as an example of a double cab in FIGS. 1 and 2, but is mounted on a front frame 2a having a flat floor (8) and a low ground height. In FIG. 7, which shows the hydraulic circuit, the fluid suspension is provided with hydraulic cylinders FSh, FSr, RS
h and RSr are attached, and the piping is connected. In the description of the hydraulic circuit, reference numerals of hydraulic cylinder details are limited to the front right hydraulic cylinder FSr only, and the other parts are omitted.
Further, in the subscripts of the respective devices, r indicates right and h indicates left.

As for the piping, a high-pressure pipe p0 is connected to a hydraulic pump G driven by a power source (not shown). High pressure pipe p
0 is divided into two in a first branch C1, and one becomes a front pipe p1 for the front axle and goes to a second branch C2 near the front axle via the front axle control valve Vf. Front pipe p1 at second branch C2
Is branched, one is a first high pressure pipe p1r, which is connected to the high pressure chamber Cu of the front right hydraulic cylinder FSr, and the other is a second high pressure pipe p1r.
And is connected to the high pressure chamber of the front left hydraulic cylinder FSh.

The other of the high-pressure pipe p0 branched in the first branch C1 becomes a rear pipe p2 for a rear axle and serves as a rear axle control valve Vr.
To the third branch C3 near the rear axle. In the third branch C3, the rear pipe p2 is branched, while one is in the third high-pressure pipe p3
r, which is connected to the high pressure chamber of the rear right hydraulic cylinder RSr, and the other is a fourth high pressure pipe p4h, which is connected to the high pressure chamber of the rear left hydraulic cylinder RSh. Each hydraulic cylinder FS
The pressure oils h, FSr, RSh, and RSr press the piston Pi from the high-pressure chamber Cu to raise the vehicle height.

Each of the hydraulic cylinders FSh, FSr, R
Pressure oil chamber Cs via piston Pi of Sh and RSr
Is designed to retain the amount of oil that determines the vehicle height. A first return pipe q1r is connected to the front right axle chamber Cs on the front axle, and a second return pipe q2h is connected to the front left axle chamber on each front axle, so as to return to the oil tank Gt. ing. The first return pipe q1r and the second return pipe q2h are gathered at the first gathering point D1, become the gathering pipe q0, pass through the front axle control valve Vf, pass through the third gathering point D3, and reach the oil tank Gt. The connection has been returned. The same applies to the rear axle, and the return oil from the pressure oil chamber is collected at the second collection point D2, and is passed through the rear axle control valve Vr.
It is connected to the oil tank Gt via the third meeting point D3.

The front axle height control switch SWf is connected to the front axle control valve Vf, and the rear axle height switch SWr is connected to the rear axle control valve Vr by electric wires.
Control is performed by oil supply to Sh, FSr, RSh, and RSr.

FIG. 8 shows how the front hydraulic cylinder FS of the front axle 11 is attached to the frame 2 and the front axle 11, and FIG. 9 shows how the rear hydraulic cylinder RS of the rear axle 12 is attached to the frame 2 and the rear axle 12. ing. Note that the fluid suspension is not necessarily limited to a hydraulic cylinder. For example, a diaphragm type air suspension as shown in FIG. FIG. 10 is for the rear axle, RSf is the rear front spring,
RSr indicates a rear rear spring.

Here, reference symbol Df indicates a front door, and Dr indicates a rear door. Reference symbol E indicates an engine.

The operation of the embodiment shown in FIGS. 1 to 4 and FIGS. 7 to 9 will be described. In the vehicle T with a reduced cab floor shown in FIGS. 1 to 4, the cab 1 is mounted on the front frame 2 a having a lower ground height than the frame 2, so that the ground surface of the cab 1 is lowered, so that the ascending / descending property is easily increased. Become. In addition, the floor can be flattened with a margin in the height direction due to the low floor, the cab length can be increased, the operability is improved, and the living space is increased.

The operation of the fluid suspension shown in FIGS. 7 to 9 will be described with reference to the flowchart of FIG. Step S
At 1, it is determined which axle height to change. To change the height of the front part of the vehicle, go to step S2. When changing the height of the rear part of the vehicle, the procedure goes to step S4. If the height before and after the vehicle is to be changed simultaneously, step S
Go to 3. In step S2, the front left and right hydraulic cylinders FSh and FSr are operated via the front axle control valve Vf by the front vehicle height adjustment switch SWf in FIG. Next, the procedure goes to step S5. In step S4, the rear left and right hydraulic cylinders RSh and RSr are operated via the rear axle control valve Vr by the rear vehicle height adjustment switch SWr in FIG. Next, the procedure goes to step S5. In step S3, the front and rear left and right hydraulic cylinders FSh, FSr, RSh, and RSr are operated by the front and rear vehicle height adjustment switches SWf and SWr in FIG. Next, the procedure goes to step S5. In step S5, it is determined whether to raise or lower the ground height of the vehicle front, the vehicle rear, or the entire vehicle. To raise, go to step S7; to lower, go to step S6. In step S6, the hydraulic cylinder is shortened. In step S7, the front or rear front and rear hydraulic cylinders are extended. The vehicle posture of the vehicle T by using the above steps properly is shown in FIGS. FIG. 11 shows steps S1, S3, and S6, in which the front and rear left and right hydraulic cylinders FSh, FSr, RSh, and RSr of all cylinders are shortened to lower the vehicle height. Therefore, the liftability is the best. However, the height of the obstacle that can be climbed is the lowest at H1, and the approach angle α1 is small, which is not suitable for traveling on uneven terrain.

FIG. 12 shows the state after steps S1, S3 and S7.
h, FSr, RSh, and RSr are extended to increase the vehicle height. Therefore, the elevating property is deteriorated. But,
The height of the obstacle that can be ridden increases at H2, and the approach angle α2 also increases, which is suitable for running on uneven terrain.

FIG. 13 shows steps S1, S3, and S
6 and S7, the front part of the vehicle is raised and the rear part of the vehicle is lowered, so that the height of obstacles that can be ridden increases and the approach angle α3 becomes maximum. On the other hand, the liftability is the worst, and the departure angle γ indicating the poor contact with the rear end of the vehicle and the proximity is minimized.

FIGS. 5 and 6 show another embodiment in which the cab is lifted and lowered by improving the frame, that is, the front end of the frame 2 is lowered. FIG. 5 shows the connecting member 15A.
Is formed so as to eliminate the vertical offset, and to lower the ground height by inclining the joint portion of the front frame 2A.
In this manner, the connecting member 15A is simplified, lightened, and the cab 1 can be mounted on a low floor.

FIG. 6 shows that the hollow rectangular member 15Ba is connected to the frame 2 so that the ground height of the front frame 2B is further reduced.
Bb connects the front frame 2B. In this way, even when the frame 2 and the front frame 2B have a large vertical difference so that they cannot be directly connected, the cab 1 can be mounted on a low floor by connecting the hollow rectangular members 15Ba.

[0033]

The effects of the present invention are listed below. (1) A front frame having a reduced height above the ground is connected to the front end of the frame by a connecting member, and the cab is mounted on the front frame having a lower height above the ground. (2) Since the length of the front end of the frame can be freely increased, the inside of the cab can be widened and the occupant's comfort can be improved. (3) Since the height of the cab above the ground can be reduced, the height of the ladder mounting and the like can be made large, and a high-performance device can be mounted. (4) Since the ground height of the cab can be reduced, the position of the center of gravity of the vehicle is lowered, and the running stability and the stability of on-site work are increased. (5) Since the front frame having a low height above the ground is connected to the frame by the connecting member, a mass-produced frame can be used, and it is technically difficult and can be easily manufactured without newly installing an expensive press die. (6) In addition to the above-described effects of lowering the floor, the front part of the vehicle and the rear part of the vehicle can be freely moved up and down by the fluid suspension. Therefore, if elevating property is required, the hydraulic cylinder is shortened to lower the vehicle height. If you need to ride on uneven terrain, you can extend the hydraulic cylinder to increase the vehicle height. If you want to raise the front or rear of the vehicle, you can increase the approach angle by raising the front and lowering the rear. . In addition, by adopting such a structure, the cab length can be increased, and the cab comfort and workability can be further improved.

[Brief description of the drawings]

FIG. 1 is an explanatory side view of a vehicle showing an embodiment of the present invention.

FIG. 2 is a side view of a ladder fire truck in which a ladder is mounted on the vehicle of FIG. 1;

FIG. 3 is a side view of the left side of the frame showing the frame shape of FIG. 1;

FIG. 4 is a top view of FIG. 3;

FIG. 5 is a side view of the left side of the frame showing another frame shape.

FIG. 6 is a side view of the left side of the frame showing another frame shape.

FIG. 7 is a hydraulic suspension circuit diagram.

FIG. 8 is a side view showing a hydraulic cylinder for a front axle.

FIG. 9 is a side view showing a rear axle hydraulic cylinder.

FIG. 10 is a side view showing an air suspension.

FIG. 11 is a side view of the vehicle when the vehicle height is lowered by a hydraulic suspension.

FIG. 12 is a side view of the vehicle when the vehicle height is increased by a hydraulic suspension.

FIG. 13 is a side view of the vehicle when the front vehicle height is increased and the rear vehicle height is decreased by a hydraulic suspension.

FIG. 14 is a flowchart showing a method of changing a vehicle attitude by a hydraulic suspension.

FIG. 15 is a side view illustrating the configuration of a conventional vehicle, and the ability to get over obstacles and approach.

FIG. 16 is a side view of a front suspension using a leaf spring mounted in FIG. 15;

FIG. 17 is a side view of a rear suspension by the parent-child spring mounted in FIG. 15;

[Explanation of symbols]

 FOH · · · front overhang FS · · · front fluid suspension RS · · · rear fluid suspension T · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ··· Rear passenger seat 8 ··· Floor 11 ··· Front axle 12 ··· Rear axle 15 ··· Joining member

Claims (2)

[Claims] 1. A low-floor double cab vehicle comprising: a ladder-type frame supported above a front axle and a rear axle via a suspension; and a cab mounted on the frame. A front frame lower than the upper surface of the frame is connected to a front end portion of the frame in front of a front axle via a connecting member, the cab is mounted on the front frame, and the suspension is constituted by a fluid suspension. A low-floor double cab vehicle characterized by: 2. The low floor double cab vehicle according to claim 1, wherein said fluid suspension is a hydraulic cylinder.