JPH0549513B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a four-wheel steering system used in a vehicle.

BACKGROUND ART In recent years, four-wheel steering, in which front wheels and rear wheels are steered, has been used in automobiles, and there is a trend to improve steering performance and driving safety.

The four-wheel steering is typically performed with front power steering and rear power steering, and in particular, the rear power steering is steered in conjunction with the front power steering.

Since the rear wheels were steered by power steering in the same manner as the front wheels, the steering system was expensive and required a large oil pump.

Purpose and problem of the invention The purpose and problem of this invention is to
In connection with steering, the mechanism for steering the rear wheels is simplified, avoiding an increase in the capacity of the oil pump, facilitating four-wheel steering, and, in particular, making the front wheels and rear wheels in the same phase and in opposite phases. A four-wheel steering system used in a vehicle that improves steering performance and driving safety by making it possible to steer the front wheels and the rear wheels independently of each other so that only the front wheels can be steered. On offer.

Summary of the structural invention related to the object/problem: Contents of the claimed invention In relation to the above-mentioned objective/problem, the four-wheel steering system used in the vehicle of the present invention has a four-wheel steering system that is capable of swinging at both ends of the front wheels. Front power steering that steers a pair of front wheel axles that are connected and rotatably support the front wheels, and a single-rod double-acting cylinder on the input side and a single-rod double-acting cylinder on the output side that are connected oppositely to each other. an opposed steering phase cylinder fixedly disposed on the chassis between the front axle and the rear axle, a front power steering link mechanism on the front wheel axle side, and the opposed steering phase cylinder on the front wheel axle side. a relay link connecting the input piston rod of its input double-acting cylinder in the opposed steering phase cylinder; and a rear drag link connecting its tip to the output piston rod of its output double-acting cylinder in the opposed steering phase cylinder. and a rear knuckle arm that is connected to the rear end of the rear drag link and then swingably connected to both ends of the axle to steer a pair of rear wheel axles that rotatably support the rear wheels; Cylinder independent piping that connects the head side and rod side cylinder chambers of the input double acting cylinder to each other; cylinder independent piping that connects the head side and rod side cylinder chambers of the output double acting cylinder to each other; Cylinder in-phase piping that connects the head-side cylinder chambers of the output-side double-acting cylinder to each other, cylinder in-phase piping that connects the rod-side cylinder chambers of the input and output-side double-acting cylinders, and the input-side double-acting cylinder. The cylinder reverse phase piping connects the rod side cylinder chamber of the output side double acting cylinder to the head side cylinder chamber of the cylinder, and the head side cylinder chamber of the output side double acting cylinder is connected to the rod side cylinder chamber of the input side double acting cylinder. It is composed of connecting cylinder reverse phase piping and directional control valves arranged in each piping, and the opposed steering phase cylinder is hydraulically independent from the front power steering, and the cylinder is independent. Piping,
The directional control valves arranged in the cylinder in-phase piping and cylinder anti-phase piping are selectively opened and closed, and the head side and rod side cylinder chambers of the input side and output side double acting cylinders in the opposed type steering phase cylinder are and to steer its front and rear wheels, in particular in connection with the steering of its front power steering;
Thereafter, the wheels can be steered in the same phase and in opposite phases, and the front wheels and rear wheels can be steered independently of each other, so that only the front wheels can be steered.

Description of Specific Examples Preferred specific examples of the four-wheel operation system used in the vehicle according to the present invention will be described below with reference to the drawings.

1 to 4 show a specific example 10 of a four-wheel steering system used in a vehicle according to the present invention, which is applied to a truck 70. FIG.

The four-wheel steering system 10 includes a front power steering system 11 that is swingably connected to both ends of a front axle 72 and that steers a pair of front wheel axles 73 and 74 that rotatably support front wheels 92 and 93. , an input-side single-rod type double-acting cylinder 13 and an output-side single-rod type double-acting cylinder 1 connected oppositely to each other.
4, an opposed steering phase cylinder 12 fixedly arranged on the chassis 71 between the front axle 72 and the rear axle 82, and a linkage mechanism of the front power steering 11 on the side of the front wheel axle 73. 37 and its opposed steering phase cylinder 1
The relay link 15 connects the input piston rod 51 of its input double-acting cylinder 13 at 2, and the tip connects to the output piston rod 52 of its output double-acting cylinder 14 at the opposed steering phase cylinder 12. A pair of connected rear drag links 16 and a pair of wheels connected to the rear end of the rear drag link 16 and then swingably connected to both ends of the axle 82 to rotatably support rear wheels 94 and 95. Rear knuckle arm 17 for steering rear wheel axles 83, 84, cylinder independent piping 18, 19, cylinder in-phase piping 20,
21, cylinder reverse phase piping 22, 23, and direction control valves 24, 25, 2 arranged in those piping 18, 19, 20, 21, 22, 23, respectively.
6, 27, 28, and 29.

The front power steering 11 is
power cylinder 30, oil pump (not shown), flow control oil (not shown), control valve 31, oil reservoir (not shown), steering wheel 33,
It is composed of a steering shaft 34, a pitman arm 35, a front drag link 36, and a front knuckle arm 37.

In this front power steering 11, its power cylinder 30, oil pump, flow control valve, control valve 31, and oil reservoir are connected to supply hydraulic piping (not shown) and return hydraulic piping (not shown). The flow control valve is connected to the return hydraulic line by a power cylinder bypass (not shown).

The power cylinder 30 has a control valve 31 and a steering gear box 32 that allows manual steering.
It is configured in an itengular type including the following, and is swingably connected to both ends of a front axle 72 disposed in front of the chassis 71 of the truck 70 via knuckles 75, 76 and king pins 77, 78, The pitman arm 35, front drag link 36, and front knuckle arm 3 are attached to a pair of front wheel axles 73 and 74 that rotatably support the front wheels 92 and 93, respectively.
They are connected via 7. Of course, the front wheel axles 73 and 74 are connected to each other by a tie rod 79 and a pair of tie rod arms 80 and 81.

Further, the control valve 31 is gear-coupled to the steering shaft 34 and is operated by the steering wheel 33 via the steering shaft 34.

The opposed steering phase cylinder 12 is connected to the head cover 4, as can be seen from FIGS. 2-4.
0 are shared with each other, the input side cylinder body 38 and the output side cylinder body 39 are integrated, and the input side single rod type double acting cylinder 13 and the output side single rod type double acting cylinder 14 are connected oppositely to each other. It is manufactured with a structure that Of course, the integrated input and output double-acting cylinders 13, 14 are secured to the chassis 71 by bolt-and-nut means (not shown).

The input-side single-rod type double-acting cylinder 13 is fitted into an input-side cylinder body 38 having a cylinder bore 43 so as to be able to reciprocate and slide therein, and has a head in the cylinder bore 43. Side and rod side cylinder chambers 45, 46
An input side piston 49 forming an input side cylinder body 38, one end of which is fixed to the input side piston 49, and the other end extended so as to be removable from the outside of the input side cylinder body 38 through the hole 53 of the rod cover 41. The input side cylinder body 38 includes a head side and a rod side cylinder chamber 4.
Head-side and rod-side oil ports 55, 56 are formed, which are open at 5, 46.

The output side single rod type double acting cylinder 14 is manufactured in the same shape as the input side single rod type double acting cylinder 13, and includes an output side cylinder body 39 having a cylinder and a bore 44, and the cylinder body 39 having a bore 44.
An output side piston 50 is fitted into the bore 44 so as to be able to reciprocate and slide, and forms head side and rod side cylinder chambers 47, 48 within the cylinder bore 44, and one end is fixed to the output side piston 50, and the The output side piston rod 52 extends through the hole 54 of the rod cover 42 so that its other end can be inserted into and taken out from the outside of the output side cylinder body 39. 39 is formed with head side and rod side oil ports 57, 58 which are open to the head side and rod side cylinder chambers 47, 48.

The relay link 15 is made from a rod, and its front link on the front wheel axle 73 side
The tip of the front knuckle arm 37, which is the link mechanism of the power steering 11, is connected by a ball joint, and the input side piston of the input side single rod type double acting cylinder 13 in the opposed type steering phase cylinder 12. - The rear end is connected to the other end of the rod 51 by a ball joint, and the steering of the front power steering 11 is transmitted to the double-acting cylinder 13 on the input side.

The rear drag link 16 is connected to the relay link 15 and the front drag link 3.
6, the output piston rod 52 of the output single-rod double-acting cylinder 14 in the opposed steering phase cylinder 12.
The tip is connected to the other end with a ball joint, so that the movement of the single rod type double acting cylinder 14 on the output side can be transmitted to the rear knuckle arm 17.

The rear knuckle arm 17 is ball jointed to the rear end of the rear drag link 16 and then swingably connected to both ends of the axle 82, and then rotatably drives the wheels 94, 95. A pair of supported rear wheel axles 83 and 84 are connected to the front power steering 11 side, and the opposed steering phase cylinder 12 controls the steering of the front power steering 11 in the same phase or in opposite phase. Wheels 94, 95
to steer. Of course, the rear knuckle arm 17 is connected to the rear knuckle arm 17 by fitting the knuckles 85, 86 with the wheel axles 83, 84 onto the king pins 87, 88, and then connecting the tires swingably connected to both ends of the wheel 82. - Fixed to one of the rod arms 90, 91.

The tie rod arms 90, 91 are also connected to each other by a tie rod 89 in the conventional manner.

One of the cylinder independent pipes 18, 19 is connected between the head side and rod side oil ports 55, 56 of the input side single rod type double acting cylinder 13 of the opposed steering phase cylinder 12,
The head side and rod side cylinder chambers 45, 4
6 are connected to each other, and the other of the cylinder independent piping 18, 19 is connected to the head side and rod side oil port 5 of the output side single rod double acting cylinder 14 of the opposed steering phase cylinder 12.
7 and 58 to connect the head side and rod side cylinder chambers 47 and 48 to each other.

One of the cylinder in-phase pipes 20 and 21 is
connected between the head side oil ports 55, 57 of the input side and output side single rod double acting cylinders 13, 14 of the opposed steering phase cylinder 12, connecting the head side cylinder chambers 45, 47 to each other; Moreover, the cylinder in-phase arrangement 20,
The other of 21 is its opposed steering phase cylinder 12
Input side and output type single rod type double acting cylinder 1
3, 14 rod side oil port 56,
58, and its rod side cylinder chamber 4
6 and 48 are connected to each other.

One of the cylinder reverse phase pipes 22 and 23 is
The opposed steering phase cylinder 12 is connected to the head oil port 55 of the input single-rod double-acting cylinder 13 and the rod-side oil port 58 of the output single-rod double-acting cylinder 14, The rod side cylinder chamber 48 is connected to the head side cylinder chamber 45, and the other side of the cylinder reverse phase piping 22, 23 is connected to the input side single rod type double acting cylinder 13 in the opposed type steering phase cylinder 12. rod side oil port 56 and its output side single rod type double acting cylinder 14
is connected to the head side oil port 57,
The rod side cylinder chamber 46 is connected to the head side cylinder chamber 47.

The directional control valves 24, 25, 26, 27, 2
Reference numerals 8 and 29 indicate electromagnetic two-way control valves, which are arranged corresponding to the pipings 18, 19, 20, 21, 22, and 23. Of course, those directional control valves 2
4, 25, 26, 27, 28, 29 are switch box (not shown) solenoid coils 59, 60, 61, 6 located near the driver's seat.
2, 63, and 64 are electrically connected, and are opened and closed by operating a switch in the switch box.

Next, the four-wheel steering system 1 configured as described above will be described.
The operation of the truck 70 will be described in relation to the running condition of the truck 70.

First, referring to FIGS. 1 and 2, we will discuss the case where the truck 70 is running at a low speed. If the truck 70 is running at a low speed, the switch box Operate the switch and apply current to the solenoid coils 63 and 64 to control the directional control valve 2.
8, 29 are opened, the current is cut off to the solenoid coils 59, 60, 61, 62, and the directional control valves 24, 25, 26, 27 are closed.

As such, the directional control valves 28, 29 are opened and the directional control valves 24, 25, 26,
27 is closed, the cylinder reverse phase piping 22 connected to the head side oil port 55 and the rod side oil port 58 connects the head side cylinder chamber 45 of the input side double acting cylinder 13 and its output side double acting cylinder 13. Rod side cylinder chamber 4 of dynamic cylinder 14
8 are connected to each other, and the rod side oil port 56 and the head side oil port 5
The rod side cylinder chamber 4 of the input side double acting cylinder 13 is connected to the cylinder reverse phase piping 23 connected to 7.
6 and the head-side cylinder chamber 47 of its output-side double-acting cylinder 14 are in communication with each other. 48, and the rod-side cylinder chamber 46 of the input double-acting cylinder 13 and the head-side cylinder chamber 4 of the output double-acting cylinder 14.
7 and the output side piston 5.
The movement of the input piston 49 is reversed with respect to that of the input piston 49, so that in the opposed steering phase cylinder 12 the movement is set in antiphase.

After all, it is rotatably supported by the front wheel axles 73, 74, and is steered by the front power steering 11 via the front wheel axles 73, 74. The phase of the front wheels 92, 93 is controlled via a relay link 15 to its opposed steering phase cylinder 12.
further transmitted from the opposed steering phase cylinder 12 to the rear wheel axles 83, 84 to the rear drag link 16, rear knuckle arm 17, and tie rod arm 90;
Those rear drag link 16, rear nutcle arm 17, tie rod arm 90,
Tie Rod 89 and Tie Rod Arm 9
1, but then the wheel axles 83, 8
The actual steering angles of the rear wheels 94, 95 rotatably supported by the rear wheels 94, 95 are set to be synchronized with those of the front wheels 92, 93 in opposite phases.

Therefore, if the track 70 is at a low speed, e.g.
When driving at a speed below Km/h, the front wheel 9
2,93 is steered by its front power steering 11, then the wheels 9
4 and 95 are steered in antiphase synchronization by their opposed steering phase cylinders 12.

Next, with reference to FIGS. 1 and 3, we will discuss the case where the truck 70 is driven at a high speed, for example, 30 km/h or more. At the switch box, operate the switch to apply current to the solenoid coils 61, 62 to open the directional control valves 26, 27, and also to the solenoid coils 59, 60, 63, 64.
Turn off the current and close the directional control valves 24, 25, 28,
Close 29.

As such, the directional control valves 26, 27 are opened and the directional control valves 24, 25, 28,
29 is closed, the cylinder in-phase piping 20 connected between the head side oil ports 55 and 57 connects the head side cylinder chamber 45 of the input side double acting cylinder 13 and the head side of the output side double acting cylinder 14. The cylinder chamber 47 of the input side double acting cylinder 13 is connected to the rod side cylinder chamber 46 of the input side double acting cylinder 13 through the cylinder in-phase piping 21 connected between the rod side oil ports 56 and 58. The rod-side cylinder chambers 48 of the moving cylinders 14 are in communication with each other, and oil is supplied to the head-side cylinder chambers 45 of the input-side double-acting cylinders 13 and the head-side cylinder chambers 4 of the output-side double-acting cylinders 14.
It also flows freely between the rod-side cylinder chamber 46 of the input-side double-acting cylinder 13 and the rod-side cylinder chamber 48 of the output-side double-acting cylinder 14. The movement of the piston 50 will be the same with respect to that of its input piston 49, so that in its opposed steering phase cylinders 12 the motion is set in phase.

As a result, the phase of the front wheels 92, 93 rotatably supported by the front wheel axles 73, 74 and steered by the front power steering 11 via the front wheel axles 73, 74 is determined by the relay. Its opposed steering phase cylinder 1 via a link 15
2 and further from the opposed steering phase cylinder 12 to the rear wheel axles 83, 84 to the rear drag link 16, rear knuckle arm 17, and tie rod arm 90;
Those rear drag link 16, rear nutcle arm 17, tie rod arm 90,
The power is transmitted through the tie rod 89 and the tie rod arm 91, and then the wheel axle 83,
The actual steering angles of the rear wheels 94 and 95 rotatably supported by the rear wheels 84 are set to be in phase and synchronized with those of the front wheels 92 and 93.

Therefore, when the truck 70 is traveling at high speed, the front wheels 92, 93 are
If steered by the power steering 11, the wheels 94, 95 are then steered in phase and synchronization by their opposed steering phase cylinders 12.

Next, referring to FIGS. 1 and 4, a case will be described in which the truck 70 runs by steering only the front wheels 92 and 93. In this case, the switch is operated at the switch box, and the Current is applied to the solenoid coils 59, 60 to open the directional control valves 24, 25, and current is turned off to the solenoid coils 61, 62, 63, 64 to open the directional control valves 26, 27, 28, 2
Close 9.

As such, the directional control valves 24, 25 are opened and the directional control valves 26, 27, 28,
29 is closed, the cylinder independent piping 18 connected between the head side and rod side oil ports 55 and 56 connects the double acting cylinder 13 on the input side.
Head side and rod side cylinder chambers 45, 46
are connected to each other, and the head side and rod side cylinder chambers 4 of the output side double acting cylinder 14 are connected to each other, and the cylinder independent piping 19 is connected between the head side and rod side oil ports 57, 58.
7 and 48 are in communication with each other, and oil flows freely between the head side and rod side cylinder chambers 45 and 46 in the input side double acting cylinder 13, and
In the output side double acting cylinder 14 as well, fluid flows freely between the head side and rod side cylinder chambers 47, 48, and the input side and output side pistons 49,
50 are freely slid back and forth within the corresponding cylinder bores 43,44. That is, the double-acting cylinders 13 and 14 on the input and output sides perform free motion.

Therefore, when the front wheels 92, 93 are steered by the front power steering 11 via the front wheel axles 73, 74, the steering of the front power steering 11 is controlled by the relay.
Its opposed steering phase cylinder 1 via link 15
However, in the opposed steering phase cylinder 12, the input side and output side double acting cylinders 13, 14 perform free motion.
Steering of the front power steering 11 is performed via the rear drag link 16, rear knuckle arm 17, etc., and then the wheel axle 8.
3, 84, and eventually the front wheels 92,
Only 93 is steered, and in this case wheels 94, 95 are then placed in a self-steer condition.

Further, after the wheels 94 and 95 are returned to the straight-ahead state, the switch is operated at the switch box to apply current to the solenoid coil 59 to open the directional control valve 24 and open the other directional control valve. If 25, 26, 27, 28, 29 are closed, then the wheels 94, 95 can also be placed in the steer lock condition. However, in order to maintain the wheels 94, 95 in a steer-locked condition thereafter, the truck 70 preferably includes a steer-lock means including an air chamber.

Conveniences and Benefits of the Invention From the above, compared to the four-wheel steering systems used in vehicles that have already been proposed and used, the four-wheel steering system used in the vehicle of the present invention Front power steering that steers a pair of front wheel axles that are swingably connected to both ends and rotatably support the front wheels; a single-rod double-acting cylinder on the input side and the output side that are connected oppositely to each other; an opposed steering phase cylinder consisting of a single-rod double-acting cylinder and fixedly disposed on the chassis between the front axle and the rear axle; a front power steering link mechanism on the front wheel axle side; A relay link connecting the input piston rod of the input double-acting cylinder in the opposed steering phase cylinder, and a tip connecting the output piston rod of the output double-acting cylinder in the opposed steering phase cylinder. and a rear wheel shaft that steers a pair of rear wheel axles that are connected to the rear end of the rear drag link and then swingably connected to both ends of the wheels to rotatably support the rear wheels.・Natsukuru・
An arm, independent cylinder piping that connects the head side and rod side cylinder chambers of its input double acting cylinder to each other, cylinder independent piping that connects the head side and rod side cylinder chambers of its output side double acting cylinder, and Cylinder in-phase piping that connects the head-side cylinder chambers of the input-side and output-side double-acting cylinders to each other; cylinder in-phase piping that connects the rod-side cylinder chambers of the input-side and output-side double-acting cylinders to each other; and its input side Cylinder reverse phase piping that connects the rod side cylinder chamber of the output side double acting cylinder to the head side cylinder chamber of the double acting cylinder, and the head side of the output side double acting cylinder to the rod side cylinder chamber of the input side double acting cylinder. Since the four-wheel steering system used in the vehicle of this invention includes cylinder reverse phase piping that connects the cylinder chambers and directional control valves arranged in these piping, the opposite type steering phase The cylinder is hydraulically independent from its front power steering, and its directional control valves are selectively opened and closed, and its cylinder independent piping, cylinder in-phase piping, and cylinder anti-phase piping provide opposed steering. The head side and rod side cylinder chambers of the input side and output side double acting cylinders of the phase cylinder are switched and connected, and the output side double acting cylinder is operated in the same phase and in opposite phase to the input side double acting cylinder, and Its input and output double-acting cylinders are freely extended and retracted, its opposed steering phase cylinders are set for in-phase operation, anti-phase operation, and free motion, and its front wheels are controlled by its front power steering. and at the same time the rear wheels can be steered in phase and out of phase by means of its opposed steering phase cylinders in conjunction with the steering of its front power steering, and It becomes possible to steer only the front wheels, thus improving steering performance and driving stability, and moreover, the oil pump for subsequently steering the wheels is omitted, so that the so-called oil pump capacity is reduced. This suppresses the increase in power consumption of the engine mounted on the vehicle, which is useful for four-wheel steering of the vehicle.

Relationship between the invention and specific examples As mentioned above, from the specific examples of this invention explained with reference to the drawings, for those who have ordinary knowledge in the technical field to which this invention pertains,
Various design modifications and changes can be easily made, and furthermore, the content of this invention is essential to the realization of the invention that accomplishes the task of the invention,
It is derived from the technical essence of the invention, which is the nature of the invention, and can be easily replaced by an embodiment that is objectively recognized as incorporating it.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a four-wheel steering system used in a vehicle of the present invention applied to a truck, and FIG. 2 is a schematic diagram of a four-wheel steering system used in the four-wheel steering system shown in FIG. FIG. 3 is a hydraulic circuit diagram with its opposed steering phase cylinders in an in-phase condition, and FIG. 4 is a hydraulic circuit diagram with its opposed steering phase cylinders in a free motion condition. It is a circuit diagram. 11...Front power steering, 1
2...Opposed type steering phase cylinder, 13...Input side single rod type double acting cylinder, 14...Output side single rod type double acting cylinder, 15...Relay link, 1
6...Rear drag link, 17...Rear
Knuckle arm, 18, 19... Cylinder independent piping, 20, 21... Cylinder in-phase piping, 2
2, 23... Cylinder reverse phase piping, 24, 25,
26, 27, 28, 29... Directional control valve.

Claims (1)

[Claims] 1. Front power steering that is swingably connected to both ends of the front axle and that steers a pair of front wheel axles that rotatably support the front wheels; and inputs that are connected oppositely to each other. an opposed steering phase cylinder consisting of a single-rod type double-acting cylinder on the side and a single-rod type double-acting cylinder on the output side, fixedly disposed on the chassis between the former axle and the rear axle; A relay connecting the front power steering linkage and the input piston rod of its input double-acting cylinder in its opposed steering phase cylinder.
a rear drag link that connects its tip to the output piston rod of its output double-acting cylinder in its opposed steering phase cylinder; A rear knuckle arm that is swingably connected to both ends and that steers a pair of rear wheel axles that rotatably supports the rear wheels, and the head side and rod side cylinder chambers of the input side double acting cylinder are connected to each other. Cylinder independent piping, cylinder independent piping that connects the head side and rod side cylinder chambers of the output side double acting cylinder to each other, and cylinder in-phase piping that connects the head side cylinder chambers of the input side and output side double acting cylinder to each other , cylinder in-phase piping that connects the rod-side cylinder chambers of the input and output double-acting cylinders to each other, and the rod-side cylinder chamber of the output double-acting cylinder connected to the head-side cylinder chamber of the input double-acting cylinder. Cylinder reverse phase piping that connects, cylinder reverse phase piping that connects the rod side cylinder chamber of the input double acting cylinder to the head side cylinder chamber of the output double acting cylinder, and directional control placed on each of those piping. A four-wheel steering system used in vehicles that includes valves.