JP2816464B2 - Cab air suspension system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cab air suspension device for a cab-over type truck and a tractor having a tilt type cab.

[0002]

2. Description of the Related Art A cab-over type truck equipped with a so-called tilt type cab in which a cab is rotated around a tilt axis disposed near a lower end of a front end portion thereof for tilting up when an engine is maintained or inspected. And recently, in tractors, etc., to improve the riding comfort of the cab,
A cab has been proposed in which the front and rear ends of the cab are mounted on a chassis frame via air spring devices.

[0003] As is well known in the art, the air spring device is connected to a source of compressed air via a leveling valve, and the leveling valve is a load acting on the air spring device, in other words, the air spring device. In response to the bending, the compressed air is supplied from the compressed air source to the air spring device, or the compressed air in the air spring device is discharged to the outside air, so that the height of the cab relative to the chassis frame is always kept constant. It works as follows.

As disclosed in Japanese Utility Model Laid-Open Publication No. 63-158481, for example, the above-mentioned leveling valves are conventionally all fixed to the chassis frame side, and the free ends of operating levers for controlling the operation of the leveling valves are conventionally known. The other end of the connecting rod whose one end is pivotally connected to the portion is connected to an appropriate member on the cab side to detect the vertical displacement of the cab with respect to the chassis frame, that is, the deflection of the air spring device.

In the above-described conventional configuration, the leveling valve,
In particular, since the leveling valve that supplies and discharges compressed air to the air spring device that is provided near the front end of the cab is fixed to the chassis frame side, the ground level is naturally low, and the leveling valve and the connecting rod are exposed to muddy water when traveling in rainy weather. Therefore, there is a great deal of fouling and there is concern about durability.

Further, the cab mounted on the chassis frame via the air spring device is tilted up around a tilt axis disposed near the lower end of the front end portion of the cab during inspection and maintenance of the engine and the like. Since the relative displacement of the air spring device with respect to the leveling valve fixed to the chassis frame side is remarkably large, as a means for supplying compressed air from the leveling valve to the air spring device, conventionally, the air spring device is exclusively provided from the chassis frame side to the cab side. A complicated piping structure is adopted, in which compressed air that has passed through the leveling valve is once led to the cab tilt shaft by the dedicated piping, and then supplied to the air spring device via a flexible hose from the tilt shaft. Therefore, there is a problem that the manufacturing cost increases.

[0007]

SUMMARY OF THE INVENTION The present invention provides a leveling valve for supplying / discharging compressed air to / from an air spring device, which can be disposed at a sufficiently high level as compared with the prior art. And a cab air suspension device that can effectively prevent the occurrence of the turbulence, improve the durability thereof, and simplify the structure of the leveling valve and the compressed air supply piping of the air spring device to reduce the manufacturing cost. It is intended to provide.

[0008]

SUMMARY OF THE INVENTION The present invention has been devised to achieve the above object, and has an air spring device for mounting a front end of a cab near a chassis frame, and compressed air is supplied to the air spring device. Leveling for supplying compressed air and supplying compressed air in the air spring device in accordance with a load acting on the air spring device and interposed in an air pipe connecting the air spring device and the compressed air source. A valve, wherein the leveling valve is fixed to the cab side, and an operation lever of the leveling valve is connected to the chassis frame via a connecting rod. It is a suggestion.

[0009]

According to the structure of the present invention, since the leveling valve is fixed to the cab side, the leveling valve can be disposed at a sufficiently high position as compared with the conventional structure in which the leveling valve is fixed to the chassis frame side. Therefore, contamination due to muddy water or the like during traveling can be effectively reduced. Also,
Since the relative displacement between the leveling valve and the air spring device when the cab is tilted up can be made sufficiently smaller than before, the compressed air piping can be simplified.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. In the drawing, reference numeral 10 denotes a chassis frame of a cab-over type truck or tractor, which includes a pair of left and right side rails 12 extending in the front-rear direction of the vehicle body, and rivets at both ends of the side rails 12 arranged in the vehicle width direction.
And a plurality of cross members 14 fixed by bolts or the like. Reference numeral 16 denotes a cab of the truck. The cab has a main sill or under frame 18 as a strength member fixed to the floor.

The side rails 12 of the chassis frame 10
A bracket 20 is fixed to the upper side of the front end of the connecting arm 24. A front end of a connecting arm 24 is pivotally attached to the bracket 20 via a tilt shaft 22. A bracket 26 is fixed below the front end of the main sill 18, and a rear end of the connecting arm 24 is pivotally connected to the bracket 26 by a pivot 28.

An air spring device 30 having an appropriate structure is interposed between the bracket 26 at the front end of the cab and the connecting arm 24. The lower seat member 32 of the air spring device having a cup shape has a lower central portion. Are fixed to the connecting arm 24 by a screw shaft 34 protruding from the connecting arm 24 and a nut 36 screwed to the screw shaft. As shown in FIG. 2, the cup-shaped upper seat member 36 of the air spring device 30 is accommodated in a cylindrical seat portion 38 formed on the bracket 26 and having an increased diameter. An air bellows 40 made of rubber is interposed between the lower seat member 32 and the upper seat member 36.

The left and right main sills 18 of the cab 16 are provided.
Are connected by a pipe-shaped cross member, that is, a cross pipe 42, disposed near the front end in the vehicle width direction. A plurality of brackets 44 are fixed on the cross pipe 42 by welding or the like, and a valve support 48 is supported on the bracket 44 via bolts 46. A well-known leveling valve 52 is fixed to and supported by the valve support 48 by bolts 50.

The operating lever 5 of the leveling valve 52
4 has one free end pivotally connected to an upper end of a vertically arranged connecting rod 58 via a ball joint 56, and a lower end of the connecting rod 58 pivotally connected to a bracket 62 via a ball joint 60. ing. The bracket 62 has its lower end fixed to the cross member 14 disposed at the front end of the chassis frame 10 by a bolt 64.

As shown in FIG. 1, a stay 66 is fixedly fastened together with the valve support 48 to the bracket 44 on the cross pipe 42, and a front grill 68 is attached to the stay 66.

As shown in FIG. 2, the leveling valve 52 is preferably disposed as close as possible to a center plane 0-0 of the chassis frame 10 in the vehicle longitudinal direction. The connection port 70 of the leveling valve 52 and the air inlet 72 provided in the lower seat member 32 of the air spring device 30 are connected by a flexible air hose 74 shown by a two-dot chain line in FIG. .

Next, in the compressed air circuit diagram shown in FIG. 3, reference numeral 76 denotes an air tank or a compressed air source for storing compressed air discharged from an air compressor driven by an engine of a truck, and 78 denotes a brake device for a rear wheel. Compressed air booster for operating, 80 is a compressed air booster for operating a brake device of a front wheel, 82 is a compressed air booster for operating a clutch device, and these boosters are shown in the figure. It is arranged on the right side of the line A, that is, on the chassis frame 10 side. On the other hand, an air horn 84, an air pressure gauge 86, and a brake valve 88 that is activated by the driver depressing a brake pedal are provided on the left side of the line B in FIG. The inlet 90 is connected to a compressed air line of the air horn 84. The chassis frame 10 on the right side of the line A and the cab 16 side on the left side of the line B are connected by a plurality (five in the illustrated case) of rising air hoses 92. Incidentally, reference numeral 94 in the figure denotes a shock absorber.

In the cab air suspension system having the above structure, when the cab 16 is in the normal running position shown by the solid line in FIG. 1, the weight change of the occupant of the cab 16 and the load, and the vertical movement during the running. When the cab 16 is displaced vertically with respect to the chassis frame 10 and, for example, the front end portion of the cab 16 is no longer lower than a preset height, the operating lever 54 of the leveling valve 52 is moved clockwise in FIG. The air inlet 9 is swung and rises from the air tank 76 through the air hose 92.
The compressed air supplied to the air spring 70 is supplied from the connection port 70 through the air hose 74 to the air inlet 72 of the air spring device 30.
Flows into the air bellows 40 through the
Rises to the set height. Conversely, cab 16
Is higher than the set height, the connecting rod 58
As a result, the operation lever 54 is rotated counterclockwise in FIG. 2, and the compressed air in the air spring device 30 is discharged from the air inlet 72 to the outside air through the air hose 74 and the connection port 70 from the exhaust port of the leveling valve 52. , The front end of the cab 16 descends to the set height.

Next, when the cab 16 is tilted up for inspection and maintenance of the engine and the like, pressurized oil is supplied to a tilt cylinder (not shown), and the cab 16 is tilted.
1 in the counterclockwise direction in FIG.
(The position of the front grill 68 at the time of tilting up is indicated by a two-dot chain line in the figure.) At this time, the leveling valve 52 is fixed to the cab 16 and rotates integrally with the cab. Bracket 26 and chassis frame 1
The air spring device 30 interposed between the bracket 24 and the bracket 24 pivotally mounted on the 0 side also rotates slightly following the cab during the rotation of the cab 16, but substantially follows the cab. By providing a suitable slack in advance, sufficient durability can be ensured.

Further, the connection port 70 of the leveling valve 74 and the air inlet 72 of the air spring device 30 can be directly connected by the air hose 74, and a pipe branched from a compressed air pipe for an air horn 84 in the cab 16. Compressed air through the leveling valve 52
Supply to the air inlet 90, the configuration of the compressed air piping is greatly simplified as a whole as compared with the conventional configuration in which the leveling valve is fixed to the chassis frame 10, and the production cost is correspondingly reduced. be able to.

Further, the leveling valve 52 is connected to the cab 1
6, the leveling valve can be arranged at a sufficiently high position as compared with the conventional configuration in which the leveling valve is fixed on the chassis frame 10, and therefore, the leveling valve 52 and the connecting rod 58, especially the traveling rod 58 during traveling, can be provided. The contamination of the ball joints 56 and 60 at both ends thereof by muddy water and the like can be reduced, and the deterioration of durability due to exposure to muddy water and the like can be effectively improved.

[0022]

As described above, the air suspension device for a cab according to the present invention includes an air spring device for mounting the vicinity of the front end of the cab on a chassis frame, and compressed air for supplying compressed air to the air spring device. And a leveling valve interposed in an air pipe connecting the air spring device and the compressed air source, and supplying and discharging compressed air in the air spring device according to a load acting on the air spring device. Wherein the leveling valve is fixed to the cab side, and the operating lever of the leveling valve is connected to the chassis frame via a connecting rod, and the leveling valve is connected to the muddy water of the connecting rod. It is possible to reduce the contamination and improve the durability. It is to simplify advantage capable of reducing the manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a side view showing a cross section of a part of a cab air suspension device according to an embodiment of the present invention.

FIG. 2 is a front view of the apparatus shown in FIG. 1 with a front grill 68 removed.

FIG. 3 is a compressed air circuit diagram of the entire vehicle including the cab air suspension device shown in FIG. 1;

[Explanation of symbols]

 Reference Signs List 10 chassis frame 12 side rail 14 cross member 16 cab 18 main sill 22 tilt shaft 30 air spring device 42 cross pipe 48 valve support 52 leveling valve 54 operating lever 58 connecting rod 74 air hose

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B62D 31/00-39/00 B62D 24/02

Claims (1)

(57) [Claims] 1. An air spring device that mounts a front end portion of a cab on a chassis frame, a compressed air source that supplies compressed air to the air spring device, and an air tube that connects the air spring device and a compressed air source. A leveling valve interposed in the road and supplying and discharging compressed air in the air spring device according to a load acting on the air spring device, wherein the leveling valve is fixed to the cab side; An air suspension device for a cab, wherein an operating lever of a leveling valve is connected to the chassis frame via a connecting rod.