JPH0347229B2 - - 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 enabling safe turning without impairing the turning performance of the vehicle.

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 are capable of light and quick steering. For this purpose, various types of 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 hydraulic pump as the hydraulic power supply source for the power steering, the pressure receiving area of the power piston as the output mechanism of the power steering, etc. As the steering force is determined by It has been difficult to sufficiently reduce steering fatigue in such cases by using extremely small operating force.

In addition, the supply capacity of the hydraulic pump has been increased,
Furthermore, the hydraulic pump and power piston are designed to increase the pressure receiving area of the power piston.
If the piston is made larger, the above-mentioned stationary capacity can be increased, but with such a configuration, the load on the engine that drives the hydraulic pump becomes extremely large, and the large supply capacity of the hydraulic pump is not required. Even when driving at high speeds, a large load was applied to the engine, which tended to reduce fuel consumption.

It is an object of the present invention to at least perform stationary operation when a vehicle is stopped and steering when running at a slow speed, sufficiently reducing fatigue caused by such steering, and, moreover, increasing the size of a hydraulic pump. This enables such steering without having to increase the pressure area of the power piston, and also minimizes the load on the engine that drives the hydraulic pump, improving the fuel consumption rate of the engine. Our goal is to provide steering systems for use in vehicles that require

In order to solve these problems, the steering system used in the vehicle of the present invention includes a hydraulic pump, a main power cylinder that steers a pair of front wheel axles swingably connected to both ends of the front axle, and a main power - A pair of front and rear wheel axles are swingably connected to both ends of the front and rear axles to supplement the steering force of the cylinders, and an auxiliary power cylinder is connected to one of the frontmost wheel axles. A control valve, controlled by the steering gear box, that changes the flow of pressure oil from the hydraulic pump to the main and auxiliary power cylinders, and
Open tandem that switches the flow of pressure oil from the cylinder chamber of its main power cylinder to the cylinder chamber of its auxiliary power cylinder so that the cylinder is engaged and its auxiliary power cylinder is free. - Consists of a center valve.

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

1 and 2 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 truck 67. FIG.

This steering system 10 steers a front-most wheel axle 18 and front and rear wheel axles 19 whose steering angles are changed in conjunction with each other in a front two-axle type truck 67, and a hydraulic pump 11 and its front-most wheel axle 18 are steered. The main power 9 cylinder 12 and the steering force of the main power cylinder 12 are supplemented.
An auxiliary power cylinder 13 connected to the front and rear wheel axles 19 side and interlocked with the main power cylinder 12; A control valve 14 that changes the flow of pressurized oil sent to It consists of an open tandem center valve 15 that is opened and closed by
When the truck 67 is stopped or running at a slow speed, the auxiliary power cylinder 13 is linked to the main power cylinder 12, and when the truck 67 is running under conditions other than the above, the auxiliary power cylinder 13 is linked to the main power cylinder 12. 13 cylinder chambers 32,3
3 are in communication with each other and their auxiliary power cylinder 13 is free.

Hydraulic pump 11 is driven by an engine (not shown) mounted on its truck 67 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 hydraulic pressure for its main and auxiliary power cylinders 12, 13, but the supply capacity of existing hydraulic pumps
The supply capacity of the hydraulic pump 11 is set based on the output of its main power cylinder 12 only, as it is set based on the output of the cylinder. 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 34 on the side of the frontmost wheel axle 18, and the end of its operating rod 22 to the side of the chassis 68 of the truck 67.

The idle arm 34 is connected to the chassis 68.
The main power cylinder 12 is driven to rotate the chassis 68 in the front-rear direction using the upper end rotatably connected to the fulcrum as a fulcrum, thereby changing the steering angle of the wheel 69 attached to the frontmost wheel axle 18.

That is, the knuckle 16 including the frontmost wheel axle 18 is configured in a substantially L-shape with a knuckle arm 38 and a tie rod arm 39, 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 axle 80 via a king pin 42, and furthermore, the lower end of its idle arm 34, which is rotatably connected to its chassis 68, is connected via a drag link 36. It is connected to the end of the nutcle arm 38.

Of course, the ends of the tie rod arms 39 of the pair of knuckles 16 are connected to each other via the tie rod 45.

Therefore, its main power cylinder 12 is actuated and its idle arm 34 engages its shaft 68.
When the wheel is rotated in the longitudinal direction, the pair of knuckles 16 rotate around the king pin 42, and the frontmost wheel axle 18 is steered.

The auxiliary power cylinder 13 has its main power
The main power cylinder 12 is connected to the front and rear wheel axles 19 so as to supplement the steering by the cylinder 12, and is connected to the main power cylinder 12 by pressure oil sent from the hydraulic pump 11 via the control valve 14, which will be described later. has been done.

That is, the auxiliary power cylinder 13 is
A hydraulic cylinder similar to the main power cylinder 12, having a cylinder 27 and a piston 28 slidably fitted within the cylinder 27;
The operating rod 29 has one end that can be taken in and out from one end of the cylinder 27 and the other end is connected to the piston 28, and the other end of the cylinder 27 is connected to the idle arm 35 on the front and rear wheel axle 19 side. Connect the operating rod 29 end to the shaft 68.
Each side is rotatably connected.

The idle arm 35 is substantially similar to the idle arm 34 on the front wheel axle 18 side described above.
With the upper end rotatably connected to the chassis 68 as a fulcrum, the chassis 68 is rotated in the front-rear direction by driving the auxiliary power cylinder 13,
The steering angle of the wheels 70 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 provided with the frontmost wheel axle 18, the knuckle 17 includes a knuckle arm 40 and a tie rod arm 41, respectively, and has a substantially L-shape. They are rotatably arranged at both ends via king pins 43, and furthermore, the shaft 6
The lower end of the idler arm 35, which is rotatably connected to the idler arm 8, is connected to the end of the knuckle arm 40 via a drag link 37.

Of course, the ends of the tie rod arms 41 of the pair of knuckles 17 are connected to each other via the tie rod 46, and the idle arms 3
5 is connected to the idle arm 34 on the frontmost wheel axle 18 side via a relay rod 44.

Therefore, its auxiliary power cylinder 13 is actuated, and its idle arm 35 is driven by its shaft 6.
8, the pair of knuckles 17 rotate around the king pin 43, and the front and rear wheel axles 19 are steered. The force is transmitted via the relay rod 44 to the idler arm 34 on the side of the front-most wheel axle 18, thereby supplementing the steering force of the main power cylinder 12.

The control valve 14 connects the pump ports 47, the main and auxiliary power cylinders 1
a left-turn pressure port 48 for driving the main and auxiliary power cylinders 12, 13 to the left-turn side, a right-turn pressure port 49 for driving the main and auxiliary power cylinders 12, 13 to the right-turn side, and a reservoir port 50, respectively; , a four-way control valve incorporating a spool (not shown) selectively connecting its pump port 47 to its left-turn pressure port 48, right-turn pressure port 49, and reservoir port 50; The spool is configured to slide back and forth when driven by.

The control lever 51 is driven in response to operation of the steering wheel 53 of the truck 67. In other words, the control
The lever 51 is connected to the pitman arm 54 of the steering gear box 52 in its track 67 via a connecting rod.

The pump port 47 of the control valve 14 configured as described above is connected to the discharge port of its hydraulic pump 11 via a hydraulic supply line 60, and its left turn pressure port 48 is connected to its main power supply via a left turn hydraulic line 61. Left turn port 23 of cylinder 12
, the right turn pressure port 49 is connected to the right turn hydraulic piping 62.
to the right turn port 24 of its main power cylinder 12 via the reservoir port 50;
Oil reservoir 66 via hydraulic return line 65
are connected to each other.

The open tandem center valve 15 is
A valve casing with a pair of primary power cylinder ports 56, 57 and a pair of auxiliary power cylinder ports 58, 59, respectively, in communication with the spool chamber;
It consists of a spool arranged in a chamber so as to be able to slide back and forth, and an electromagnetic coil that electromagnetically slides the spool back and forth.When the electromagnetic coil is not energized, the main power cylinder port 5
6 and 57, respectively, and connects its auxiliary power cylinder ports 58 and 59 to each other, and also connects its main power cylinder port 56 to its auxiliary power cylinder when its electromagnetic coil is energized.・Port 58 connects its main power cylinder port 57 to its auxiliary power cylinder.
The cylinder ports 59 are configured to communicate with each other.

The open tandem center valve 15
The electromagnetic coil is electrically connected to an amplifier (not shown) that amplifies a signal from a vehicle speed sensor (not shown), and is used when the truck 67 is stopped and when it is traveling at a slow speed. It is configured to be energized when

The open tandem center valve 15 so configured is connected to its main power cylinder 1.
2 and its auxiliary power cylinder 13 are provided in left-turn and right-turn hydraulic pipes 63, 64.

That is, its open tandem center
A pair of main power cylinder ports 56, 57 of valve 15 are connected to left and right turn ports 23, 24 of its main power cylinder 12, and a pair of auxiliary power cylinder ports 58, 59 are connected to its auxiliary power cylinder 12. It is connected to the left turn and right turn ports 30 and 31 of the cylinder 13, respectively.

Next, to describe the running of the front two-axle truck 67 equipped with the above-mentioned steering system 10, when the truck 67 is stopped, the electromagnetic coil of the open tandem center valve 15 is excited by a signal from the vehicle speed sensor. , whose main power cylinder port 56 is connected to its auxiliary power cylinder port 58 and whose main power cylinder port 57 is connected to its auxiliary power cylinder port 5.
9 have been contacted.

In such a state, the hydraulic pump 11 is driven by the engine mounted on the truck 67, and the operating force of the steering wheel 53 is applied to the control valve 14 via the steering gear box 52. - If the spool of that control valve 14 is slid to either side, the pump port 47 of that control valve 14 will be transmitted to the lever 51 and the pump port 47 of that control valve 14 will be connected to the left-turn and right-turn pressure ports 48, 49.
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 67 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. done by force.

Of course, even when the truck 67 is running at a slow speed, the main and auxiliary power cylinders 1 are pumped with 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 67 increases and the vehicle runs normally, the electromagnetic coil of the open tandem center valve 15 is no longer energized by the signal from the vehicle speed sensor, and the main power cylinder port 56, 57 are each closed and their auxiliary power cylinder ports 58, 59 are in communication with each other.

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
7 is connected to a reservoir port 50 and the pressure oil from its hydraulic pump 11 is returned to an oil reservoir 66.

In the steering system 10 described above, the main power cylinder 12 and the control valve 1
It is also possible to configure 4 integrally, in which case,
The steering system 10 is smaller and more easily applicable to vehicles. Similarly, the control valve 14 and the steering gear box 52 may be integrally constructed, or the main power cylinder 12, the control valve 14, and the steering gear box 52 may be integrally constructed. or additionally, the auxiliary power cylinder 13
By integrally configuring the steering system 10 and the open tandem center 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 hydraulic pump,
A main power cylinder that steers a pair of front wheel axles is swingably connected to both ends of the front axle, and a main power cylinder is swingably connected to both ends of the front and rear axles to supplement the steering force of the main power cylinder. a pair of front and rear wheel axles and an auxiliary power cylinder connected to one of the frontmost wheel axles; A control valve for varying the flow rate of the supplied pressure oil and a control valve for controlling the auxiliary power cylinder to either engage the main power cylinder or free the auxiliary power cylinder. an open tandem center valve for switching the flow of pressure oil from the cylinder chamber of the power cylinder to the cylinder chamber of its auxiliary power cylinder; is conducted from the cylinder chamber of the main power cylinder, and the open tandem center valve engages the main power cylinder with the auxiliary power cylinder and frees the auxiliary power cylinder. If the vehicle is in any of the following states:
Steering at slow speeds is accomplished with extremely low operating forces, and the fatigue caused by such steering is significantly reduced, especially compared to the case where the main and auxiliary power cylinders are connected independently to the control valve. Loss flow of pressure oil flowing from the control valve to the main power cylinder and auxiliary power cylinder, so-called wasted flow of pressure oil is reduced, and the auxiliary power cylinder and open tandem center valve The joint that connects the main power cylinder to the control valve is omitted from the hydraulic passage that connects the main power cylinder to the control valve, reducing the pressure loss of the pressure oil due to passage resistance, and thereby reducing the power loss in the hydraulic pump and power cylinder.・An increase in the pressure-receiving area of the piston is avoided, the load on the engine that drives the hydraulic pump is minimized, the fuel consumption rate of the engine is improved, and the auxiliary power is transferred from the main power cylinder. As a result of the open tandem center valve being used to switch the pressure oil flowing into the cylinder, the structure of the switching valve is simplified, the valve is miniaturized, and the hydraulic circuit is simplified; Commercially available valves have become available, and with them,
The device can be manufactured cheaply and is very useful and practical for large vehicles.

[Brief explanation of drawings]

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. FIG. 2 is a schematic diagram showing a structure around a wheel axle. 10... Steering system used in a vehicle, 1
1...Hydraulic pump, 12...Main power cylinder, 1
3... Auxiliary power cylinder, 14... Control valve, 15... Open tandem center valve, 18... Frontmost wheel axle, 19... Front and rear wheel axles.

Claims (1)

[Claims] 1. A hydraulic pump, a main power cylinder that steers a pair of front wheel axles swingably connected to both ends of the front axle, and a main power cylinder configured to supplement the steering force of the main power cylinder. A pair of front and rear wheel axles are swingably connected to both ends of the front and rear axles, and an auxiliary power cylinder is connected to one of the frontmost wheel axles. A control valve that changes the flow rate of pressure oil supplied from a hydraulic pump to its main and auxiliary power cylinders, and a state in which the auxiliary power cylinder is interlocked with its main power cylinder and its auxiliary power cylinder.
An open tandem center switch that switches the flow of pressure oil from the cylinder chamber of its primary power cylinder to the cylinder chamber of its auxiliary power cylinder so as to place the cylinder in one of the free conditions.
Steering systems used in vehicles, including valves. 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 Its auxiliary power cylinder and open
A steering system for use in a vehicle according to claim 1, wherein the tandem center valve is integrally constructed.