JPH0330545B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steering system used in a vehicle.

A steering system that steers the front wheel axle of a vehicle, such as a truck or a passenger car, has a system that reliably and easily steers the front wheel axle in response to steering input from the driver, that is, in response to steering wheel operation. However, there is a growing demand for vehicles to be able to make complete turns without impairing their turning performance.

Furthermore, in recent years, in addition to traffic congestion and parking problems, the number of vehicle users has expanded, and users' demands for better steering performance have led to improvements in steering systems that allow for light and quick steering. For this purpose, various power steering devices have been proposed.

However, in this type of power steering, the force required for steering depends on the supply capacity of the oil pump as the hydraulic pressure supply source for the power steering, and the pressure receiving area of the power piston as the output mechanism of the power steering. Therefore, the range of changes in steering force is inevitably limited, and in particular, the steering ability is limited. It has been difficult to do this with an extremely small operating force and to sufficiently reduce steering fatigue in such cases.

Furthermore, if the oil pump and power piston are made larger to increase the supply capacity of the oil pump and the pressure receiving area of the power piston, the above-mentioned stationary capacity will be increased. However, with such a configuration, the load on the engine that drives the oil pump becomes extremely large, and even when driving at high speeds when the oil pump does not require a large supply capacity, a large load is placed on the engine. The fuel consumption rate tended to decrease significantly.

It is an object of the present invention to at least perform steering when the vehicle is stopped and at slow speeds with an extremely small operating force, to sufficiently reduce the fatigue caused by such steering, and to reduce the fatigue caused by such steering. This enables such steering without increasing the pressure area of the power piston or increasing the pressure receiving area of the power piston, and further reduces the load on the engine that drives the oil pump as much as possible, reducing the fuel consumption rate of the engine. The purpose of the present invention is to provide a steering system used in a vehicle that improves performance.

In view of these problems, the steering system used in the vehicle of the present invention includes a relay rod whose both ends are rotatably connected between the steering link mechanism of the frontmost wheel and the steering link mechanism of the front and rear wheels; A main power cylinder connected to the steering link mechanism of the frontmost wheel, an auxiliary power cylinder connected to one of the steering linkage mechanism of the frontmost wheel and one of the steering linkages of the front and rear wheels, and a main power cylinder connected to the steering linkage mechanism of the frontmost wheel, is controlled by the steering gear box,
a control valve for varying the flow rate of pressurized oil from the hydraulic pump to its main and auxiliary power cylinders, and from the main and auxiliary power cylinders to an oil reservoir, respectively; The control valve includes a switching valve that switches the pressure oil flowing from the control valve to the auxiliary power cylinder so that the auxiliary power cylinder is in a state in which the auxiliary power cylinder is linked to the auxiliary power cylinder and in a state in which the auxiliary power cylinder is free.

Hereinafter, specific examples of the steering system used in the vehicle of the present invention will be described with reference to the drawings.

1 to 4 show a specific example 10 of a steering system used in a vehicle according to the present invention, which is applied to a front two-axle type truck 86.

In this steering system 10, a front-most wheel 87 is rotatably supported by a front-most wheel shaft 18 that is swingably connected to both ends of the front-most wheel, and front and rear wheels 88 are swingably connected to both ends of the front and rear axles. This is applied to the front two-axle type truck which is rotatably supported by the front and rear wheel axles 19, and both ends are connected between the steering link mechanism of the frontmost wheel 87 and the steering link mechanism of the front and rear wheels 88. a relay rod 40 rotatably connected to the front wheel 8;
The main power cylinder 12 is connected to the steering link mechanism of the front and rear wheels 88, and the auxiliary power cylinder 13 is connected to the steering link mechanism of the front and rear wheels 88.
a control valve controlled at 8 to vary the flow rate of pressurized oil from the hydraulic pump 11 to its main and auxiliary power cylinders 12, 13, and simultaneously from the main and auxiliary power cylinders 12, 13 to the oil reservoir 85, respectively; 14 and the left and right hydraulic piping 7 connecting its control valve 14 to its auxiliary power cylinder 13
9 and 80, the switching valve 15 is opened and closed according to the vehicle speed, and the auxiliary power cylinder 13 is interlocked with the main power cylinder 12 when the truck 86 is stopped or running at a slow speed. In addition, when the truck 86 runs under conditions other than those described above, the auxiliary power cylinder 1
The pressure oil in the cylinder chambers 91 and 92 of No. 3 is released to the oil reservoir 85 side, and the auxiliary power cylinder No.
It was assembled where 3 was free.

In this truck 86, a steering link mechanism is attached to the frontmost wheel 87, and the steering link mechanism is connected to the nutcle 16, the drag link 32, and the idle arm 30.
In addition, the steering link mechanism of the front and rear wheels 88 includes the knuckle 17, the drag link 33,
And, it was assembled including the idle arm 31.

Hydraulic pump 11 is driven by an engine (not shown) mounted on its truck 86 and is configured to generate hydraulic pressure for driving main and auxiliary power cylinders 12 and 13, which will be described later. The hydraulic pump 11 generates the hydraulic pressure for the main and auxiliary power cylinders 12, 13, but the hydraulic pressure is adjusted so that the supply capacity of the existing oil pump is set based on the output of the power cylinders. The delivery capacity of pump 11 is set based on the output of its main power cylinder 12 only. Of course, the hydraulic pump 11 has substantially the same configuration as an existing hydraulic pump, so a description of its configuration will be omitted.

The main power cylinder 12 is a hydraulic cylinder,
Consisting of a cylinder 20, a piston 21 fitted into the cylinder 20 so as to be able to reciprocate and slide, and an operating rod 22 whose one end can be taken in and out from one end of the cylinder 20 and whose other end is connected to the piston 21. has been done.

The main power cylinder 12 has the other end of its cylinder 20 rotatably connected to the idler arm 30 on the front-most wheel axle 18 side, and its operating rod 22 end rotatably connected to the chassis 93 side of the truck 86.

The idle arm 30 is connected to the chassis 93.
With the upper end rotatably connected to as a fulcrum, the main power cylinder 12 is driven to rotate the chassis 93 in the front-rear direction, changing the steering angle of the wheel 87 attached to the frontmost wheel shaft 18.

That is, the knuckle 16 provided with the frontmost wheel axle 18 is configured in a substantially L-shape, including a knuckle arm 34 and a tie rod arm 35, respectively, similar to the knuckle in the existing front two-axle type truck. Natsukuru 1 configured as follows
6 is rotatably arranged at both ends of the frontmost wheel side beam (not shown) via king pins 38, and furthermore, the lower end of the idle arm 30 rotatably connected to the chassis 93 is dragged.・The knuckle arm 3 via the link 32
Connected at four ends.

Of course, the ends of the tie rod arms 35 of the pair of nuts 16 are connected to each other via the tie rod 41.

Therefore, its main power cylinder 12 is actuated and its idle arm 30 is driven by its chassis 93.
, the pair of knuckles 16 rotate around the king pin 38,
The frontmost wheel axle 18 is steered.

The auxiliary power cylinder 13 has its main power
It is connected to the front and rear wheel axles 19 side so as to supplement the steering force by the cylinder 12, and the control
It is configured to operate in conjunction with its main power cylinder 12 by means of pressure oil sent from its hydraulic pump 11 via a valve 14.

That is, the auxiliary power cylinder 13 is
A hydraulic cylinder similar to the main power cylinder 12, having a cylinder 25 and a piston 26 slidably fitted within the cylinder 25;
It consists of an operating rod 27 whose one end can be taken in and out from one end of the cylinder 25 and whose other end is connected to the piston 26, and the other end of the cylinder 25 is connected to the idle arm 31 on the front and rear wheel axle 19 side. Connect the operating rod 27 end to its shirt 93.
Each side is rotatably connected.

The idle arm 31 is substantially similar to the idle arm 30 on the front wheel axle 18 side described above.
The upper end rotatably connected to the chassis 93 is used as a fulcrum, and the chassis 93 is rotated in the front-rear direction by driving the auxiliary power cylinder 13.
The steering angle of the wheels 88 attached to the front and rear wheel axles 19 is changed.

The knuckle 17 including the front and rear wheel axles 19 is
Similar to the above-mentioned knuckle 16 equipped with the frontmost wheel axle 18, the knuckle arm 36 and the tie rod arm 37 are respectively provided, and the knuckle 17 is configured in a substantially L-shape. The idler arms 31 are rotatably arranged via king pins 39 at both ends of the beam (not shown), and further, the lower ends of the idler arms 31, which are rotatably connected to the chassis 93, are connected via drag links 33. It is connected to the end of the nutcle arm 36.

Of course, the ends of the tie rod arms 37 of the pair of knuckles 17 are connected to each other via the tie rod 42, and the idle arm 3
1, the idle arm 30 on the frontmost wheel axle 18 side is connected via a relay rod 40.

Therefore, its auxiliary power cylinder 13 is actuated, and its idle arm 31 is driven by its shaft 9.
3, the pair of knuckles 17 rotate around the king pin 39, and the front and rear wheel axles 19 are of course steered. The force is transmitted via the relay rod 40 to the idler arm 30 on the front-most wheel axle 18 side, thereby supplementing the steering force from the main power cylinder 12.

The control valve 14 connects the pump ports 43, the main and auxiliary power cylinders 1
a left-turn pressure port 44 for driving the main and auxiliary power cylinders 12, 13 to the left-turn side, a right-turn pressure port 45 for driving the main and auxiliary power cylinders 12, 13 to the right-turn side, and a reservoir port 46, respectively; , a four-way control valve incorporating a spool (not shown) selectively connecting its pump port 43 to its left-turn pressure port 44, right-turn pressure port 45, and reservoir port 46; The spool is configured to be driven back and forth by the drive of the spool.

The control lever 47 is actuated in response to operation of the steering wheel 49 of the truck 86. In other words, the control
The lever 47 is connected via a connecting rod 51 to the pitman arm 50 of the steering gear box 48 on its track 86.

The pump port 43 of the control valve 14 configured as described above is connected to the discharge port of the hydraulic pump 11 via the hydraulic supply line 76, and the left turn pressure port 44 is connected to its main line via the left turn hydraulic lines 77, 80. and auxiliary power cylinder 12,
13, its right-turn pressure port 45 to its main and auxiliary power cylinders 12, 13, its right-turn ports 24, 29 via right-turn hydraulic lines 78, 79, and its reservoir port 46 to The control valve 15 is connected to an oil reservoir 85 via a pair of reservoir ports 65 and 66, which will be described later.

The switching valve 15 is provided in left-turn and right-turn hydraulic pipes 79 and 80 that connect the control valve 14 and the auxiliary power cylinder 13, and is configured to be opened and closed according to the vehicle speed of the truck 86. .

The switching valve 15 is connected to the spool bore 53
and multiple ports 54, 55, 56, 57, 6
0, 61, 65, 66, a spool 67 disposed in its spool bore 53 so as to be able to slide back and forth, a movable iron core 73 that makes the spool 67 slide back and forth, and an electromagnetic coil 7.
4 is the basic configuration.

That is, the switching valve 15 has a valve casing 52 with a spool bore 53.
, a pair of control valve ports 54 and 55 formed at a predetermined distance in the valve casing 52 so as to communicate with the spool bore 53, and the control valve ports 54 and 55. Spool bore 53 on the opposite side
Its valve casing 52 as contacted
a pair of auxiliary power cylinder ports 56, 57 having ring grooves 58, 59, respectively, formed at a predetermined distance from the control valve ports 54, 55 and slightly offset downwardly from the control valve ports 54, 55; and ring grooves 62 and 63 formed at a predetermined interval in the valve casing 52 so as to be connected to the spool bore 53 at a position above the control valve port 54, and ring grooves 62 and 63, respectively. an auxiliary power cylinder return port 60, 61 with a spool bore 53 located above the return port 60;
a pair of reservoir ports 65 and 66 formed facing each other so as to be in communication with each other; and a spool 67 which is arranged to be able to slide back and forth within its spool bore 53 and has a movable iron core 73 at its lower end.
and its control valve port 54,5
5 and return spool grooves 7 formed in its spool 67 to correspond to its auxiliary power cylinder return ports 60, 61;
0, 71 and its return spool grooves 70, 71 are formed in the spool 67 so as to communicate with the oil reservoir 64 at the upper end of the spool 67, that is, to communicate with the pair of reservoir ports 65, 66. Return communication path 72 and its spool 67
An electromagnetic coil 74 is arranged around the movable iron core 73 so as to slide back and forth, and the spool 67 is placed in a lifted state when the electromagnetic coil 74 is not energized. - Consists of a return spring (not shown) disposed within the bore 53.

The electromagnetic coil 74 is electrically connected to an amplifier (not shown) that amplifies a signal from a vehicle speed sensor (not shown), and the track 86
The structure is such that it is excited when the vehicle is stopped and when the vehicle is running at a very slow speed.

A pair of control valve ports 54, 55 of the switching valve 15 so configured are connected to the left-turn and right-turn pressure ports 44, 45 of the control valve 14 via left-turn and right-turn hydraulic lines 79, 80. , its pair of auxiliary power cylinder ports 56, 57 are connected to its auxiliary power cylinder 13 via left-turn and right-turn hydraulic lines 79, 80, and its auxiliary power cylinder return ports 60, 61 are connected to hydraulic return lines 79, 80. The reservoir port 65 is connected to the left and right turn hydraulic lines 79, 80 downstream of the auxiliary power cylinder ports 56, 57 via lines 83, 84, and the reservoir port 65 is connected to the hydraulic return line 8.
1 to the reservoir port 46 of that control valve 14 through the other reservoir port 66.
is connected to the oil reservoir 8 via a hydraulic return line 82.
5 respectively.

Next, to describe the running of the front two-shaft truck 86 equipped with the above-mentioned steering system 10, when the truck 86 is stopped, the electromagnetic coil 74 of the switching valve 15 is excited by a signal from the vehicle speed sensor, as shown in FIG. Spool 67 is pulled downwardly as shown, and a pair of control valve ports 54, 55 are connected to a pair of auxiliary power cylinder ports 56, 57, and auxiliary power cylinder return ports 60, 61 are connected to a pair of auxiliary power cylinder ports 56, 57. It is closed by its spool 67.

In such a state, the hydraulic pump 11 is driven by the engine mounted on the truck 86, and the operating force of the steering wheel 49 is applied to the control valve 14 via the steering gear box 48. Control·
If either of the spools of that control valve 14 is slid to one side, the pump port 43 of that control valve 14 will be connected to the left-turn and right-turn pressure ports 44, 45.
As a result, the pressure oil from the hydraulic pump 11 is sent to either one of the cylinder chambers of the main power cylinder 12 as well as to one of the cylinder chambers of the auxiliary power cylinder 13. .

Therefore, when the truck 86 is stopped, the main and auxiliary power cylinders 12, 13 are driven by the pressure oil from the hydraulic pump 11, and the front and front wheel axles 18, 19 are steered, so that the stationary motion is extremely small. It is done by manipulative power.

Of course, even when the truck 86 is running at a slow speed, the main and auxiliary power cylinders 1 are powered by pressure oil from the hydraulic pump 11, as described above.
2 and 13 are driven, and steering when traveling at very low speeds is performed with an extremely small operating force.

Furthermore, during such periods of stopping and running at very slow speeds, sudden steering is generally not required, and even if the amount of pressure oil discharged from the hydraulic pump 11 is relatively small, the main and auxiliary power cylinders 12 ,1
3 is fully driven and therefore its hydraulic pump 1
Steering can be performed by the main and auxiliary power cylinders 12 and 13 without increasing the size of the hydraulic pump 11, and the load on the engine that drives the hydraulic pump 11 can be minimized, improving the fuel consumption rate of the engine. .

Furthermore, when the traveling speed of the truck 86 increases and it runs normally, the switching valve 15
The electromagnetic coil 74 is de-energized based on the signal from the vehicle speed sensor, and the spool 67 is lifted by a return spring (not shown) as shown in FIG. 55 and auxiliary power cylinder ports 56, 57, respectively, are closed, and auxiliary power cylinder return ports 60, 61 are connected to reservoir port 66.

That is, the pressure oil from the hydraulic pump 11 is sent only to the main power cylinder 12, and the auxiliary power cylinder 13 is free.

Therefore, steering during such driving is performed only by the main power cylinder 12, and the auxiliary power cylinder 13 substantially resists the steering by the main power cylinder 12 and responds to the steering by the main power cylinder 12. follow freely.

Of course, in the above-described steering, when the steering wheel is placed in the neutral position, the pump port 4 of the control valve 14
3 is connected to the reservoir port 46, and the pressure oil from the hydraulic pump 11 is transferred to the oil via the reservoir ports 65, 66 of the switching valve 15.
It is returned to the reservoir 85.

In the steering system 10 described above, the main power cylinder 12 and the control valve 1
4 can also be constructed integrally, in which case the steering system 10 will be smaller and more easily applicable to the vehicle. Similarly, the control valve 14 and the steering gear box 48 may be integrally constructed, or the main power cylinder 12, the control valve 14, and the steering gear box 48 may be integrally constructed. or additionally, the auxiliary power cylinder 13
By integrally configuring the steering system 10 and the switching valve 15, the steering system 10 can be downsized and its applicability to vehicles can be improved.

As understood from the above, the steering system used in the vehicle of the present invention includes a relay rod whose both ends are rotatably connected between the steering link mechanism of the frontmost wheel and the steering link mechanism of the front and rear wheels. a main power cylinder connected to the steering linkage of the frontmost wheel; an auxiliary power cylinder connected to one of the steering linkage of the frontmost wheel and the steering linkage of the front and rear wheels; and a steering input. Control valve controlled by the steering gear box to vary the flow rate of pressurized oil from the hydraulic pump to its main and auxiliary power cylinders and simultaneously from its main and auxiliary power cylinders to the oil reservoir, respectively and allows pressure oil to flow from the control valve to the auxiliary power cylinder so as to either engage the auxiliary power cylinder with the main power cylinder or disengage the auxiliary power cylinder. Since the steering system used in the vehicle of the present invention includes a switching valve for switching, when the vehicle is stationary when stopped or running at a slow speed, steering force is generated by the main and auxiliary power cylinders, so,
Supplemented by the auxiliary power cylinder, steering is possible with very little effort, sufficiently reducing steering fatigue, and when the speed of the vehicle is increased, the steering force is transferred to the main power cylinder. As the steering force is generated in this way, the size of the hydraulic pump and the power and
This type of steering becomes possible without particularly increasing the piston pressure-receiving area of the cylinder, and the load on the engine that drives the hydraulic pump can be minimized, and the fuel consumption rate of the engine can be reduced. It is very useful and practical, especially for large vehicles.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a specific example of a steering system used in a vehicle of the present invention applied to a front two-axle type truck, and FIG. 2 is a schematic diagram showing the front and front wheel axles of the steering system shown in FIG. Figure 3 is a schematic diagram showing the surrounding structure, Figure 3 is a vertical cross-sectional view showing the state in which the electromagnetic coil of the control valve in the steering system shown in Figure 1 is not excited, and Figure 4 is the same as Figure 1. FIG. 3 is a longitudinal cross-sectional view showing a state in which the electromagnetic coil of the control valve in the illustrated steering system is energized. 10...Steering system used in a vehicle,
11...Hydraulic pump, 12...Main power cylinder, 13...Auxiliary power cylinder, 14...Control valve, 15...Switching valve, 1
8... Front wheel axle, 19... Front and rear wheel axles.

Claims (1)

[Scope of Claims] 1. A relay rod whose both ends are rotatably connected between the steering link mechanism of the front-most wheel and the steering link mechanism of the front and rear wheels, and a relay rod whose ends are connected to the steering link mechanism of the front-most wheel. a main power cylinder, which is controlled by a steering gear box in accordance with steering input; a control valve for varying the flow rate of pressurized oil from the hydraulic pump to its main and auxiliary power cylinders, and from the main and auxiliary power cylinders to an oil reservoir, respectively; The state in which it is linked to and its auxiliary power
A steering system used in a vehicle that includes a switching valve that switches pressure oil flowing from the control valve to the auxiliary power cylinder so as to place the cylinder in one of the free conditions. 2. A steering system for use in a vehicle according to claim 1, wherein the main power cylinder and control valve are integrally constructed. 3. A steering system for use in a vehicle according to claim 1, wherein the control valve and steering gear box are integrally constructed. 4. A steering system for use in a vehicle according to claim 1, wherein the main power cylinder, control valve, and steering gear box are integrally constructed. 5. A steering system for use in a vehicle according to claim 1, wherein the auxiliary power cylinder and the switching valve are integrally constructed.