JP3893326B2 - Lift axle device for front biaxial car - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lift axle device for a front biaxial vehicle.
[0002]
[Prior art]
In general, a front biaxial triaxial vehicle including a front front shaft and front and rear shafts and a rear shaft to which a driving force is transmitted is applied to a large vehicle such as a truck.
[0003]
FIG. 4 shows an example of a front biaxial triaxial suspension device including a front front shaft and front and rear shafts and a rear shaft. Reference numeral 1 in FIG. 4 denotes a front biaxial triaxial vehicle, Reference numeral 2 denotes a frame of the front biaxial triaxial vehicle 1. A front end portion of the trailing leaf spring 4 a is wound around a pin 5 a and connected to a bracket 3 a fixed to the front end portion of the frame 2, and the trailing leaf spring 4 a is connected. A front front shaft 6a is attached to the middle portion, and an air spring 7a is interposed between the upper surface of the rear end portion of the trailing leaf spring 4a and the lower surface of the frame 2. It has become.
[0004]
Further, the front end portion of the trailing leaf spring 4b is wound around the pin 5b and connected to the bracket 3b fixed to the rear end of the bracket 3a at the front end portion of the frame 2, and is connected to the middle portion of the trailing leaf spring 4b. A front and rear shaft 6b is attached, and an air spring 7b is interposed between the upper surface of the rear end portion of the trailing leaf spring 4b and the lower surface of the frame 2.
[0005]
Further, the front end portion of the trailing leaf spring 4c is wound around the pin 5c and connected to the bracket 3c fixed to the rear end portion of the frame 2, and the rear shaft 6c is attached to the middle portion of the trailing leaf spring 4c. An air spring 7c is interposed between the upper surface of the rear end portion of the trailing leaf spring 4c and the lower surface of the frame 2.
[0006]
The above-described trailing leaf springs 4a, 4b, and 4c support the front and rear, left and right, and torsional loads applied to the front front shaft 6a, the front and rear shaft 6b, and the rear shaft 6c. 7a, 7b, and 7c support the vertical load applied to the front front shaft 6a, the front and rear shaft 6b, and the rear shaft 6c.
[0007]
In FIG. 4, 8a, 8b, and 8c are sub-leaf springs that are superimposed on the lower surface of each trailing leaf spring 4a, 4b, and 4c to form a double structure, 9a is a front front wheel, and 9b is front and rear. Wheels 9c are rear wheels, 10a, 10b, and 10c are shock absorbers, respectively.
[0008]
[Problems to be solved by the invention]
However, since the front biaxial triaxial vehicle 1 as described above always travels using all of the front front wheels 9a, the front and rear wheels 9b, and the rear wheels 9c regardless of the load conditions, it is in a lightly loaded state. In this case, the load applied to the rear shaft 6c to which the driving force is transmitted is reduced, and the ground load of the rear wheel 9c as the driving wheel is reduced. In particular, the rear wheel 9c slips at the time of starting or the like and cannot travel. There was a fear of becoming.
[0009]
Further, since traveling is always performed using all the front wheels 9a, the front and rear wheels 9b, and the rear wheels 9c, the rolling resistance of the wheels with respect to the road surface is increased, and the fuel consumption of the vehicle is deteriorated.
[0010]
The present invention has been made in view of the above-mentioned circumstances, and has improved the starting performance by increasing the ground load of the driving wheel and suppressing the rolling resistance of the wheel to the road surface, thereby improving the driving fuel consumption. An object of the present invention is to provide a lift axle device for an axle.
[0011]
[Means for Solving the Problems]
The present invention relates to a lift axle device for a front biaxial vehicle having a front front shaft, a front and rear shaft, and at least one rear shaft, wherein the tilt shaft is provided in a frame near the front and rear shafts, and the tilt shaft is a central fulcrum. A balance rod extending in the front-rear direction is pivotally connected, and one end portion located above the front-rear axis of the balance rod and the front-rear shaft are connected by a link mechanism that can be folded up and down, and the other end portion of the balance The hydraulic cylinder is connected to an appropriate fixed part on the frame side that is higher than the other end, and the hydraulic cylinder is configured to be operated with hydraulic fluid that is diverted from the steering hydraulic power source. It is characterized by.
[0012]
Thus, when the vehicle is in a lightly loaded state, the hydraulic cylinder is actuated by the hydraulic fluid that is diverted from the steering hydraulic source, and the other end of the balance rod is pushed down. The one end on the opposite side of the tilting shaft of the tilting portion tilts upward, and the link mechanism is pulled up to be in a straight extension state. Lifted to the side.
[0013]
As a result, the load applied to the axle to which the driving force is transmitted is increased, the ground load of the driving wheel is increased, and the driving wheel is prevented from slipping at the time of starting and the starting performance is improved.
[0014]
Further, since the front and rear wheels are lifted up to the frame side together with the front and rear shafts, the rolling resistance of the wheels with respect to the road surface is reduced, so that the traveling fuel consumption is improved and the wear of the front and rear wheels is also reduced.
[0015]
When the front and rear shafts are lifted up by the hydraulic cylinder, the front and rear shafts are gradually lifted up, so that the shock absorber also follows this to operate without shortening.
[0016]
On the other hand, the suspension stroke during normal travel with the front and rear shafts lowered is absorbed by the link mechanism being folded up and down and up and down, so that the balance scale is tilted by the suspension stroke during travel. Therefore, there is no possibility that the suspension stroke affects the hydraulic cylinder side.
[0017]
Further, in carrying out the present invention more specifically, for example, a working oil circulation line that always flows the working oil guided between the engine-driven oil pump and the steering gear box through the diversion valve and returns it to the steering gear box. And a first hydraulic control valve provided so that hydraulic oil can be appropriately extracted in the middle of the hydraulic oil circulation line, and hydraulic fluid extracted from the hydraulic oil circulation line via the first hydraulic control valve A hydraulic oil supply line that leads to the first chamber of the cylinder to cause the hydraulic cylinder to extend, a hydraulic oil return line that extracts hydraulic oil from the second chamber of the hydraulic cylinder and returns it to the oil tank, the hydraulic oil return line, A hydraulic fluid communication line that connects between the hydraulic fluid supply line, and a second fluid hydraulic fluid communication line that is provided in the middle of the hydraulic fluid communication line so that the flow of hydraulic fluid can be interrupted appropriately. It is possible to adopt a configuration in which a pressure control valve.
[0018]
In this way, when the vehicle is lightly loaded, the first hydraulic control valve is switched to extract the hydraulic oil from the hydraulic oil circulation line, while the second hydraulic control valve is switched to communicate the hydraulic oil. When the flow of the hydraulic oil in the line is interrupted, the hydraulic oil from the hydraulic oil circulation line is introduced into the first chamber of the hydraulic cylinder, the hydraulic cylinder is extended, and the other end of the balance rod is pushed down by this extension. As a result, one end of the opposite side tilts upward, whereby the link mechanism is pulled up, and the front and rear shafts are lifted up to the frame side via the link mechanism. At this time, the hydraulic fluid in the second chamber that contracts with the extension operation of the hydraulic cylinder is returned to the oil tank through the hydraulic oil return line.
[0019]
Then, in this lift-up state, the hydraulic oil from the first hydraulic control valve is stopped, and the flow of hydraulic oil between the hydraulic oil circulation line and the first chamber of the hydraulic cylinder is stopped. The hydraulic pressure is locked between the hydraulic control valve and the second hydraulic control valve, so that the operation of the hydraulic cylinder is fixed and the front and rear shafts are held up to the frame side.
[0020]
After that, when the hydraulic pressure of the hydraulic cylinder is released by switching the second hydraulic control valve and opening the hydraulic oil communication line, one end of the balance rod is pulled down by the weight of the front and rear shafts and the front and rear wheels, and the other end The hydraulic oil moves from the first chamber to the second chamber of the hydraulic cylinder while the hydraulic cylinder is contracted as a result of the rise of the hydraulic cylinder, so that the front and rear shafts are lowered and the front and rear wheels are brought into contact with the road surface. Return.
[0021]
In the normal running state thereafter, the second hydraulic control valve is closed again to return the hydraulic pressure of the hydraulic cylinder to the locked state, and the hydraulic oil in the hydraulic oil circulation line is returned to the steering gear box. It ’s fine.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described together with illustrated examples.
[0023]
1 to 3 show an example of an embodiment for carrying out the present invention. The parts denoted by the same reference numerals as those in FIG. 4 represent the same items. For convenience of explanation, the trailing in FIGS. The leaf spring 4b, the sub leaf spring 8b, and the air spring 7b (see FIG. 4) are not shown. However, the technical content of the present invention itself is not limited by the form of this type of suspension device.
[0024]
As shown in FIG. 1, the basic configuration in this embodiment is substantially the same as that of the conventional front biaxial triaxial vehicle 1 shown in FIG. 4, but the feature is the vicinity of the front and rear shaft 6b. A tilting shaft 11 is provided on the frame 2, and a balance rod 12 extending in the front-rear direction with the tilting shaft 11 as a central fulcrum is pivotally mounted. One end portion of the balance rod 12 positioned above the front-rear shaft 6b and the front-rear shaft 6b A link mechanism 13 that can be folded up and down is connected, and the other end portion of the balance rod 12 and an appropriate fixing portion on the frame 2 side higher than the other end portion are connected by a hydraulic cylinder 14. The hydraulic cylinder 14 is operated by hydraulic oil that is diverted from the steering hydraulic source.
[0025]
More specifically, as shown in a rear view in FIG. 2, a balance rod 12 is pivotally attached to a tilting shaft 11 provided on a bracket 15 inside the left frame 2, and one end of the balance rod 12 is provided. The upper end portions of the pair of left and right link mechanisms 13 are connected to each other via a connecting rod 16.
[0026]
Here, each link mechanism 13 is composed of a pair of link rods 17 and 18 which are pin-coupled so as to be bent in a "<" shape, and is restored when the spring 19 changes from a predetermined bent posture. Force is acting.
[0027]
The hydraulic cylinder 14 is supported such that the upper end portion of the cylinder body 20 is tiltable from the left frame 2 via a bracket 21 and the like, and the lower end portion of the piston rod 22 is connected to the other end of the balance rod 12. It is connected to the part so as to be tiltable.
[0028]
A hydraulic system for operating the hydraulic cylinder 14 will be described below with reference to FIG. 3. The hydraulic oil is driven between the steering gear box 24 and the oil tank 25 by the engine-driven oil pump 23. In addition, there is provided a hydraulic oil circulation line 27 for constantly flowing hydraulic oil guided between the oil tank 25 and the steering gear box 24 via the diversion valve 26 and returning it to the steering gear box 24.
[0029]
In the middle of the hydraulic oil circulation line 27, hydraulic control can be switched between two positions: a diversion state in which the hydraulic oil is extracted from the hydraulic oil circulation line 27, and a continuous circulation state in which the hydraulic oil continues to flow through the hydraulic oil circulation line 27. A valve 28 (first hydraulic control valve) is provided.
[0030]
In addition, a hydraulic oil supply line 30 is provided for guiding the hydraulic oil extracted from the hydraulic oil circulation line 27 through the hydraulic control valve 28 to the first chamber 14A above the piston 29 of the hydraulic cylinder 14 so as to extend the hydraulic cylinder 14. In addition, a hydraulic oil return line 31 for extracting hydraulic oil from the second chamber 14B of the hydraulic cylinder 14 and returning it to the oil tank 25 is provided.
[0031]
Further, the hydraulic oil return line 31 and the hydraulic oil supply line 30 are connected by a hydraulic oil communication line 32, and in the middle of the hydraulic oil communication line 32, an open state that allows the hydraulic oil to flow, A hydraulic control valve 33 (second hydraulic control valve) that can be switched to two positions in a shut-off state that shuts off the flow of hydraulic oil is provided.
[0032]
Note that reference numeral 34 in FIG. 3 denotes a check valve for preventing a backflow provided downstream of the hydraulic control valve 28 in the hydraulic oil circulation line 27.
[0033]
Thus, when the vehicle is in a lightly loaded state, the hydraulic control valve 28 is switched to the shunt state and the hydraulic oil is extracted from the hydraulic oil circulation line 27 while the hydraulic control valve 33 is switched to the shut-off state. When the flow of the hydraulic oil in the oil communication line 32 is interrupted, the hydraulic oil from the hydraulic oil circulation line 27 is introduced into the first chamber 14A of the hydraulic cylinder 14 and the hydraulic cylinder 14 is extended, and the balance operation is performed by this extension operation. The other end of 12 is pushed down, and one end on the opposite side is tilted upward. As a result, the left and right link mechanisms 13 are pulled up via the connecting rod 16 to be in a straight extension state. The front and rear shafts 6b are lifted up to the frame 2 side via the link mechanisms 13 by tilting upward. At this time, the hydraulic oil in the second chamber 14 </ b> B that contracts with the extension operation of the hydraulic cylinder 14 is returned to the oil tank 25 through the hydraulic oil return line 31.
[0034]
Then, in this lift-up state, by stopping the extraction of the hydraulic oil from the hydraulic control valve 28 and stopping the flow of the hydraulic oil between the hydraulic oil circulation line 27 and the first chamber 14A of the hydraulic cylinder 14, already The hydraulic pressure is locked with the closed hydraulic control valve 33, whereby the operation of the hydraulic cylinder 14 is fixed, and the front and rear shaft 6b is held in a state where it is lifted up to the frame 2 side.
[0035]
As a result, the load applied to the rear shaft 6c (see FIG. 4) to which the driving force is transmitted is increased, and the ground load of the rear wheel 9c (see FIG. 4) as the driving wheel is increased. This prevents the rear wheel 9c from slipping and improves the starting performance.
[0036]
Further, since the front and rear wheels 9b are lifted up together with the front and rear shafts 6b, the rolling resistance of the front and rear wheels 9b with respect to the road surface is reduced, so that the running fuel consumption is improved and the wear of the front and rear wheels 9b is also reduced. Will be.
[0037]
When the front-rear shaft 6b is lifted up by the hydraulic cylinder 14, the front-rear shaft 6b is gradually lifted up, so that the shock absorber 10b (see FIG. 4) follows this without any trouble. It will be shortened.
[0038]
After that, when the hydraulic pressure of the hydraulic cylinder 14 is released by switching the hydraulic control valve 33 and opening the hydraulic oil communication line 32, one end of the balance rod 12 is pulled down by the weight of the front and rear shafts 6b and the front and rear wheels 9b. As the other end is raised, the hydraulic cylinder 14 is contracted and the hydraulic oil moves from the first chamber 14A to the second chamber 14B of the hydraulic cylinder 14, whereby the front and rear shaft 6b is lowered, and the front and rear wheels 9b are moved. It returns to the normal driving state that is in contact with the road surface.
[0039]
In the normal traveling state thereafter, the hydraulic control valve 33 is closed again, the hydraulic pressure of the hydraulic cylinder 14 is returned to the locked state, and the hydraulic oil in the hydraulic oil circulation line 27 is returned to the steering gear box 24. Just do it.
[0040]
Here, since the suspension stroke during normal traveling with the front and rear shaft 6b lowered is absorbed by the link mechanism 13 being folded and vertically expanded and contracted, the balance rod 12 is tilted by the suspension stroke during traveling. Therefore, there is no possibility that the suspension stroke affects the hydraulic cylinder 14 side.
[0041]
Therefore, according to the above embodiment, since the ground contact load of the rear wheel 9c as the driving wheel can be increased, the starting performance can be greatly improved as compared with the prior art, and the rolling resistance of the front and rear wheels 9b with respect to the road surface is increased. Thus, the fuel consumption can be improved and the wear of the front and rear wheels 9b can be reduced.
[0042]
Further, since the hydraulic cylinder 14 is operated by using the hydraulic pressure of the steering hydraulic source, it is not necessary to newly provide a hydraulic source for lifting up the front and rear shafts 6b. And each link mechanism 13 can absorb the suspension stroke during traveling well and prevent the influence from affecting the hydraulic cylinder 14 side. The cost required to implement the axle device can be significantly reduced.
[0043]
The lift axle device for a front biaxial vehicle according to the present invention is not limited to the above-described embodiment, and includes a front front shaft, front and rear shafts, and a rear shaft to which driving force is transmitted. The present invention is not limited to the front two-shaft and three-shaft vehicles, but can be similarly applied to the front two-shaft and four-shaft vehicles in which the front two shafts and the rear two shafts are arranged, and the hydraulic cylinders are provided symmetrically. Of course, various modifications can be made without departing from the scope of the present invention.
[0044]
【The invention's effect】
According to the above-described lift axle device for a front biaxial vehicle of the present invention, various excellent effects as described below can be obtained.
[0045]
(I) Since the ground contact load of the driving wheel can be increased, the starting performance can be greatly improved as compared with the prior art, and the rolling resistance of the front and rear wheels against the road surface is reduced to improve the driving fuel consumption and the front and rear wheels. Wear can be reduced.
[0046]
(II) Since the hydraulic cylinder is operated using the hydraulic pressure of the steering hydraulic source, it is not necessary to install a new hydraulic source for lifting up the front and rear shafts. With a relatively simple structure that uses the mechanism, it is possible to absorb the suspension stroke during traveling well, and to prevent the influence from affecting the hydraulic cylinder side. The required cost can be significantly reduced.
[Brief description of the drawings]
FIG. 1 is a side view schematically showing an example of an embodiment of the present invention.
2 is a rear view relating to the structure of FIG. 1; FIG.
FIG. 3 is a system diagram showing an example of a hydraulic system that operates the hydraulic cylinder of FIG. 1;
FIG. 4 is an overall side view showing an example of a conventional suspension device for a front biaxial triaxial vehicle.
[Explanation of symbols]
1 Front biaxial triaxial vehicle (front biaxial vehicle)
2 Frame 6b Front / rear shaft 11 Tilt shaft 12 Balance rod 13 Link mechanism 14 Hydraulic cylinder 14A First chamber 14B Second chamber 21 Bracket (fixed portion)
23 Oil pump 24 Steering gear box 25 Oil tank 26 Split valve 27 Hydraulic oil circulation line 28 Hydraulic control valve (first hydraulic control valve)
30 Hydraulic oil supply line 31 Hydraulic oil return line 32 Hydraulic oil communication line 33 Hydraulic control valve (second hydraulic control valve)

Claims (2)

A lift axle device for a front biaxial vehicle having a front front shaft, a front and rear shaft, and at least one rear shaft, wherein the tilt shaft is provided in a frame near the front and rear shafts and extends forward and backward with the tilt shaft as a central fulcrum. A balance rod is pivotally connected, and the other end portion of the balance rod and the other end portion are connected to each other by a link mechanism that can be folded up and down between the one end portion located above the longitudinal axis of the balance rod and the front and rear shafts. It is configured to connect with an appropriate fixing part on the frame side at a higher place by a hydraulic cylinder, and to operate the hydraulic cylinder with hydraulic fluid that is diverted from a steering hydraulic power source. Lift axle device for front biaxial car. A hydraulic oil circulation line that constantly flows hydraulic oil guided between the engine-driven oil pump and the steering gear box through the diversion valve and returns it to the steering gear box, and the hydraulic oil is appropriately extracted in the middle of the hydraulic oil circulation line. A first hydraulic control valve provided to obtain, and an operation for extending the hydraulic cylinder by introducing hydraulic oil extracted from the hydraulic oil circulation line to the first chamber of the hydraulic cylinder via the first hydraulic control valve An oil supply line, a hydraulic oil return line that extracts hydraulic oil from the second chamber of the hydraulic cylinder and returns it to the oil tank, a hydraulic oil communication line that connects between the hydraulic oil return line and the hydraulic oil supply line, The front hydraulic pressure control valve according to claim 1, further comprising a second hydraulic control valve provided in the middle of the hydraulic fluid communication line so as to be able to cut off the flow of hydraulic fluid appropriately. Axis vehicles of lift axle unit.

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