JPH0617107B2 - Steering system used in vehicles - Google Patents

Description

The present invention relates to a steering system used in a vehicle.

Steering systems that steer the front wheel axles of vehicles, such as trucks and passenger cars, reliably and easily steer their front wheel axles in response to steering input from the driver, i.e., steering wheel operation. However, it is required to enable safe turning without impairing the turning performance of the vehicle.

Furthermore, in recent years, due to the problems of traffic and parking problems, the expansion of the user base of vehicles, and the demands of the users for steering performance, the steering system enables light and quick steering. It is required that various power steering devices, namely power
Steering has been proposed.

However, in this type of power steering, the force required for steering is the supply capacity of the hydraulic pump as the hydraulic power source of the power steering, the pressure receiving area of the power piston as the output mechanism of the power steering, etc. As a result, the range of changes in the steering force is necessarily limited, and in particular, the settling capacity is limited, and as a result,
It has been difficult to perform stationary steering when the vehicle is stopped and steering at a low speed running with an extremely small operating force, and to sufficiently reduce fatigue due to steering in such a case.

In addition, increasing the supply capacity of the hydraulic pump,
To increase the pressure receiving area of the power piston,
If these hydraulic pumps and power pistons are made larger, the above-mentioned set-up capability can be improved. However, if configured in this way, the load on the engine that drives the hydraulic pumps will become extremely large, and the large amount of power generated by the hydraulic pumps will increase. Even during high-speed traveling that does not require supply capacity, the engine is heavily loaded and the fuel consumption rate tends to decrease.

A power steering apparatus for saving energy of such an engine is disclosed in Japanese Utility Model Laid-Open No. 60-157475.

This power steering apparatus, when the vehicle travels at low speed, the auxiliary cylinder is interlocked with the power steering by the opening / closing valve, and when the vehicle travels in medium / high speed,
The auxiliary cylinder is about to be idled by the on-off valve, separated from the power steering.

However, this power steering apparatus requires an on-off valve having a special structure, which increases the cost of the apparatus.

An object of the present invention is to enable steering with a very small operating force when the vehicle is stationary and when steering at a slow speed without increasing the size of the hydraulic pump or increasing the pressure receiving area of the power piston. To reduce the load on the engine that drives the hydraulic pump as much as possible to improve the fuel consumption rate of the engine.For vehicles with two front axles, the cutting angle of the front axle during turning Is larger than that of the front and rear axles, so that it can be satisfied to make turning smoother, and it is possible to use a commercially available directional control valve to make it cheaper to manufacture. In offer.

In connection with the above-mentioned problems, the steering system used in the vehicle of the present invention is a double-acting main power steering system for steering a pair of front wheel axles swingably connected to both ends of the front axle.
The cylinder is connected to a pair of front and rear wheel shafts that are swingably connected to both ends of the front and rear axles, and the left and right cylinder chambers are left turn hydraulic pipe and right turn hydraulic pipe, and the left and right cylinder chambers of the main power cylinder. A double-acting auxiliary power cylinder that is connected correspondingly to the main power cylinder to supplement the steering force of the main power cylinder, and a steering gear box that controls the main and auxiliary power A control valve that changes the flow rate of pressure oil supplied to the cylinder, a two-way control valve that is arranged in each of the left-turning and right-turning hydraulic pipes, and the left-turning and right-turning hydraulic pipes downstream of each of the two-way control valves. The connecting communication pipes and the communication pipes arranged in the communicating pipes, and each of the two-way control valves are closed when they are opened to supplement the communication pipes. The power cylinder is interlocked with its main power cylinder, and when each of its two-way control valves is closed it is opened and its interlocking pipe shorts the left and right cylinder chambers of the auxiliary power cylinder, It also includes a cylinder interlock and free valve that idles the auxiliary power cylinder.

Hereinafter, 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 tenth embodiment of the steering system used in the vehicle of the present invention applied to the front biaxial truck 72.

The steering system 10 includes a front two-axis truck 7
2 for steering the front wheel shaft 20 and the front and rear wheel shafts 21 whose steering angles can be changed in conjunction with each other, and a hydraulic pump 11, a double-acting main power cylinder 12 for steering the front wheel shaft 20, and In order to supplement the steering force of the main power cylinder 12, a double-acting auxiliary power cylinder 13 connected to the front and rear wheel shafts 21 of the main power cylinder 12 and a steering gear box 55 are controlled in accordance with the steering input. A control valve 14 for changing the flow rate of pressure oil supplied from the hydraulic pump 11 to the main and auxiliary power cylinders 12, 13 and hydraulic pipes 6 for turning left and right thereof.
Two-way control valves 15 and 16 respectively arranged at 8 and 69
And a communication pipe 70 that connects the left-turning hydraulic pipe 68 and the right-turning hydraulic pipe 68 to each other downstream of the two-way control valves 15 and 16, and the two-way control valve 15, Each of the 16 is closed when it is open and its auxiliary power cylinder 13
To the main power cylinder 12, and when the two-way control valves 15 and 16 are closed, the left and right cylinder chambers 32 and 33 of the auxiliary power cylinder 13 are opened to the oil reservoir. Auxiliary power cylinder 1 by connecting pipe 70 without connecting to 64
And a cylinder interlock and free valve 17 which short-circuits the left and right cylinder chambers 32 and 33 of each other, and idles the auxiliary power cylinder 13, and the track 72 thereof. When the vehicle is stopped or traveled at a very low speed, the two-way control valves 15 and 16 are opened, and at the same time, the cylinder interlock and free valve 17 is closed to close the auxiliary power cylinder 13. Its main power cylinder 1
When the truck 72 is operated under a condition other than the above, the two-way control valves 15 and 16 are closed, and at the same time, the cylinder interlock and free valve 17 is opened. With the communicating pipe 70, the cylinder chambers 32 on the left and right of the auxiliary power cylinder 13,
This is where the 33 are shorted together and the auxiliary power cylinder 13 is idled.

The hydraulic pump 11 is operated by an engine (not shown) mounted on the truck 72, and is configured to generate hydraulic pressure for moving its main and auxiliary power cylinders 12, 13 which will be described in detail later. There is. The hydraulic pump 11 has its main and auxiliary power cylinders 12,
The hydraulic pressure for 13 is generated, but the supply capacity of the hydraulic pump 11 is set to the output of only the main power cylinder 12 so that the supply capacity of the existing hydraulic pump is set based on the output of the power cylinder. It is set based on.
Of course, the hydraulic pump 11 is configured substantially the same as an existing hydraulic pump, and therefore the description of the configuration is omitted.

The main power cylinder 12 is a double-acting hydraulic cylinder, and a cylinder 22, a piston 23 fitted in the cylinder 22 so as to be reciprocally slidable, and one end side of which is removable from one end of the cylinder 22. The operation rod 24 has the other end connected to the piston 23.

The main power cylinder 12 has the other end of the cylinder 22 rotatably connected to the idle arm 36 on the frontmost wheel shaft 20 side, and the operation rod 24 end to the chassis 75 side of the track 72, respectively.

The idle arm 36 is rotated in the front-rear direction of the chassis 75 by driving the main power cylinder 12 with the upper end rotatably connected to the chassis 75 as a fulcrum, and is attached to the front wheel shaft 20. The steering angle of the wheel 73 is changed.

That is, the knuckle 18 including the frontmost wheel shaft 20
Like the knuckle in the existing front two-axle truck, it is provided with a knuckle arm 40 and a tie rod arm 41, respectively, and is configured in a substantially L-shape. The knuckle 18 thus configured is the front axle. A lower end of the idle arm 36, which is rotatably arranged at both ends of the idler 80 via a king pin 44, and is rotatably connected to the chassis 75, is connected to a knuckle arm 40 via a drag link 38. It is connected to the end.

Of course, the tie rod arms 41 ends of the pair of knuckles 18 are connected to each other via the tie rod 47.

Therefore, if the main power cylinder 12 is driven and the idle arm 36 is rotated in the anteroposterior direction of the chassis 75, the pair of knuckles 18 is king.
It rotates around the pin 44 and its frontmost wheel shaft 20 is steered.

The auxiliary power cylinder 13 is connected to the front and rear wheel shafts 21 side so as to supplement the steering by the main power cylinder 12, and its control valve 14 described in detail later.
It is configured to be linked to the main power cylinder 12 by pressure oil sent from the hydraulic pump 11 via the.

That is, the auxiliary power cylinder 13 is a double-acting hydraulic cylinder similar to the main power cylinder 12, and includes a cylinder 29, a piston 30 fitted in the cylinder 29 so as to be reciprocally slidable, and one end side. Of the cylinder 29 can be taken in and out from one end of the cylinder 29, and the other end of the cylinder 29 is connected to the piston 30. The other end of the cylinder 29 is an idle shaft on the front and rear wheel shafts 21 side.
Attach the end of the operating rod 31 to the arm 37 of the chassis 75.
Each side is rotatably connected.

The idle arm 37 is mounted on the front wheel shaft 20 side of the above-mentioned chassis 75 in the same manner as the idle arm 36.
With the upper end rotatably connected to the fulcrum as a fulcrum, the auxiliary power cylinder 13 is driven to rotate the chassis 75 in the front-rear direction to change the steering angle of the wheels 74 attached to the front-rear wheel shafts 21.

The knuckle 19 provided with the front and rear wheel shafts 21 is provided with a knuckle arm 42 and a tie rod arm 43, respectively, similarly to the knuckle 18 provided with the frontmost wheel shaft 20 described above, and is configured in a substantially L-shape. The knuckle 19 constructed as described above has king pins 45 at both ends of the front and rear axles 81.
And the lower end of the idle arm 37 rotatably connected to the chassis 75 is connected to the end of the knuckle arm 42 via a drag link 39.

Of course, the ends of the tie rod arms 43 of the pair of knuckles 19 are connected to each other via a tie rod 48, and further, the idle arm 37 of the pair of knuckles 19 is connected to the front wheel shaft 2 of the front wheel axle 2.
It is connected to the 0-side idle arm 36 via a relay rod 46.

Therefore, if the auxiliary power cylinder 13 is driven and the idle arm 37 is rotated in the front-rear direction of the chassis 75, the pair of knuckles 19 rotate around the king pin 45, and the front and rear wheels thereof. The shaft 21 is steered as well as the force of the auxiliary power cylinder 13 is transmitted to the idle arm 36 on the frontmost wheel shaft 20 side via the relay rod 46 thereof.
As a result, the steering force of the main power cylinder 12 is supplemented.

The control valve 14 is the pump port 4
9, a left turn pressure port 50 for driving the main and auxiliary power cylinders 12, 13 to the left turn side, a right turn pressure port 51 for driving the main and auxiliary power cylinders 12, 13 to the right turn side, and Each has a reservoir port 52, and its pump port 49 is a left turn pressure port 50 and a right turn pressure port 5.
1 and a four-way control valve having a spool (not shown) selectively switched and connected to the reservoir port 52. The spool is reciprocally slid by the drive of the control lever 53. ing.

The control lever 53 is driven according to the operation of the steering wheel 54 of the truck 72. That is, the control lever 53 controls the steering gear box 5 of the truck 72.
The pitman arm 56 of No. 5 is connected via a connecting rod 57.

Its control valve 14 constructed as described above
The pump port 49 of the hydraulic pump 11 is connected to the discharge port of the hydraulic pump 11 via the hydraulic supply pipe 65, and the left turn pressure port 5
0 to the left turn port 27 of the main power cylinder 12 via the left turn hydraulic pipe 66, the right turn pressure port 51 to the right turn port 28 of the main power cylinder 13 via the right turn hydraulic pipe 67, and its reservoir. The port 52 is connected to the oil reservoir 64 via the hydraulic pressure return pipe 71. The left and right cylinder chambers 25 and 26 of the main power cylinder 12 are connected to the left and right cylinder chambers 32 and 33 of the auxiliary power cylinder 13 via left and right hydraulic pipes 68 and 69, respectively.

The two-way control valves 15 and 16 connect the left and right cylinder chambers 32 and 33 of the auxiliary power cylinder 13 to the left and right cylinder chambers 25 and 26 of the main power cylinder 12, respectively. Are arranged in each.

The two-way control valves 15 and 16 are connected to the respective spool chambers of the main power cylinder port 5
8, 60 and auxiliary power cylinder port 5
Valve casings each comprising 9,61, a spool reciprocally slidably disposed in its spool chamber to connect and disconnect between the ports 58,59 and 60,61, and the spool And an electromagnetic coil for electromagnetically reciprocally sliding the electromagnetic wave. When each electromagnetic coil is not excited, the ports 58,
59 and 60 and 61 are disconnected from each other, and when the respective electromagnetic coils are excited, the ports 58 and 59 and 60 and 61 are connected to each other. .

That is, the electromagnetic coils of the two-way control valves 15 and 16 are electrically connected to an amplifier (not shown) that amplifies a signal from a vehicle speed sensor (not shown), and the truck 72 stops. When the vehicle is running and at a low speed, it is excited, and when running under other conditions, it is not excited.

The cylinder interlock and free valve 17 is arranged downstream of the two-way control valves 15 and 16 in a communication pipe 70 that connects the left-turning hydraulic pipe 68 and the right-turning hydraulic pipe 68.

The cylinder interlock-and-free valve 17 is a two-way control valve, which is a valve casing having a pair of ports 62 and 63 connected to the spool chamber, and a connection and disconnection between the ports 62 and 63. So as to reciprocate in the spool chamber, and an electromagnetic coil for electromagnetically reciprocatingly sliding the spool. When the electromagnetic coil is not excited, the ports 62 , 63 contact,
When the electromagnetic coil is excited, those ports 6
It is configured to cut off between the second and the third.

That is, the electromagnetic coil of the two-way control valve 17 is electrically connected to the amplifier that amplifies the signal from the vehicle speed sensor similarly to the two-way control valves 15 and 16 described above, and the truck 72 stops. And when
It is configured such that it is excited when traveling at a low speed, and is not excited when the track 72 is traveling under other conditions.

Next, traveling of the front biaxial truck 72 including the steering system 10 will be described.
When the vehicle is stopped, the electromagnetic coils of the two-way control valves 15 and 16 and the signals from the vehicle speed sensor, and
The electromagnetic coils of the cylinder interlock and free valve 17 are respectively excited, and in the two-way control valves 15 and 16, their control valve ports 58 and 60 are their auxiliary power cylinder ports. 59 and 61 respectively, and in the cylinder interlock and free valve 17, the pair of ports 62 and 63 is shut off.

In such a state, the operation of the engine mounted on the truck 72 drives the hydraulic pump 11, and the operating force of the steering wheel 54 is controlled by the steering gear box 55. When the spool of the control valve 14 is transmitted to the control lever 53 of the valve 14 and is slid on either side, the control valve 14
Pump port 49 turns left and right turns pressure port 5
0, 51, so that the hydraulic pressure from the hydraulic pump 11 is not limited to the cylinder chamber 25 or 26 of either of the main power cylinders 12,
It is sent to one of the cylinder chambers 32 or 33 of the auxiliary power cylinder 13.

Therefore, when the truck 72 is stopped, the hydraulic pump 1
Its main and auxiliary power cylinder 1 with pressure oil from 1
2, 13 are moved and their front and front and rear wheel axles 20, 21 are steered by their main and auxiliary power cylinders 12, 13 with their auxiliary power cylinders 13 interlocking with their main power cylinders 12, result,
The stationary operation can be done with an extremely small operating force.

Also, when the truck 72 is traveling at a slight speed, the main and auxiliary power cylinders 12 and 13 are moved by the pressure oil from the hydraulic pump 11, and the auxiliary power cylinder 13 is moved, as described above. With the main power cylinder 12, the front and front and rear wheel shafts 20, 21 are connected to the main and auxiliary power cylinder 1.
The steering wheel 2 and 13 are steered, and as a result, the steering is performed with an extremely small operating force even at the time of the low speed traveling.

When the vehicle is stopped or at a low speed, sudden steering is not generally 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, 13 are not required. Is sufficiently driven, and therefore 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. , The fuel consumption rate of the engine is improved.

Further, when the traveling speed of the truck 72 rises and the vehicle travels normally, the electromagnetic coils of the two-way control valves 15 and 16 and the cylinder interlock and. The electromagnetic coils of the free valve 17 are no longer energized, and as a result the respective control valve ports 58, 60 and the auxiliary power cylinder ports 59, 61 of the two-way control valves 15, 16 are blocked. Also, its cylinder interlock and free valve 1
7, the pair of ports 62, 63 are connected to each other.

Therefore, the pressure oil from the hydraulic pump 11 is sent only to the main power cylinder 12, and at that time, the auxiliary power cylinder 13 is placed in a free state, a so-called idling state. That is, steering during such traveling is
Done with only its main power cylinder 12, and
At that time, the cylinder interlock and free valve 17 is opened and the cylinder chambers 32 and 33 of the auxiliary power cylinder 13 are short-circuited to each other by the communication pipe 70, so that the auxiliary power cylinder 13 is , Is idled and follows its steering with its main power cylinder 12 without substantially resisting it.

Of course, when steering wheel 54 is in the neutral position during steering during the above-described low speed traveling and normal traveling, the control valve 1
The pump port 49 of No. 4 is connected to the reservoir port 52 thereof, and the pressure oil from the hydraulic pump 11 is returned to the oil reservoir 64.

Further, in this front two-axle type truck 72, the turning angle of the frontmost axle 80 is larger than that of the front and rear axles 81 at the time of turning, and therefore it is necessary to satisfy the above-mentioned steering.

In this steering system 10, the auxiliary power cylinder 13 has its left and right turn hydraulic pipes 68,
It is connected to its main power cylinder 12 at 69,
When the above steering is performed, the main power cylinder 1
The hydraulic pressure rise of No. 2 is the left turn and the right turn hydraulic pipe 68,
The resistance of 69 precedes that of the auxiliary power cylinder 13 and, of course, in the above-described normal running, the auxiliary power cylinder 13 is idled and its main power
The hydraulic pressure rises only in the cylinder 12, the cutting angle of the front axle 80 is made larger than that of the front and rear axles 81, and the front biaxial truck 72 is smoothly turned.

In the steering system 10 described above, the main power cylinder 12 and the control valve 14 can be integrally configured, and in that case, the steering system 10 is downsized and can be easily applied to a vehicle. . Similarly, the control valve 14
And the steering gear box 55 thereof are integrally formed, or the main power cylinder 12, the control valve 14, and the steering gear box 55 are integrally formed. However, the steering system 10 is downsized, and the applicability to a vehicle is improved.

As can be understood from the above, the steering system used in the vehicle of the present invention is a double-acting main power cylinder that steers a pair of front wheel axles that are swingably connected to both ends of the front axle. It is connected to a pair of front and rear wheel shafts that are swingably connected to both ends of the front and rear axles, and the left and right cylinder chambers are left turn hydraulic pipes and right turn hydraulic pipes that correspond to the left and right cylinder chambers of the main power cylinder. A double-acting auxiliary power cylinder connected to the main power cylinder to supplement the steering force of the main power cylinder, and a steering
A control valve that is controlled by a gear box and that changes the flow rate of pressure oil supplied from the hydraulic pump to its main and auxiliary power cylinders, and a two-way control valve that is placed in each of the left-turn and right-turn hydraulic pipes, And a communication pipe that connects the left-turning hydraulic pipe and the right-turning hydraulic pipe to each other downstream of the two-way control valve,
And, when each of the two-way control valves is closed, the auxiliary power cylinder is linked with the main power cylinder, and when each of the two-way control valves is closed, the two-way control valves are opened. Cylinder interlock and free, in which the left and right cylinder chambers of the auxiliary power cylinder are short-circuited to each other by the communication pipe, and the auxiliary power cylinder is idled.
Since it includes a valve, in the steering system used in the vehicle of the present invention, pressure oil flowing in the left and right cylinder chambers of the auxiliary power cylinder is guided from the corresponding left and right cylinder chambers of the main power cylinder, And that 2
The directional control valve is opened and, at the same time, its cylinder interlock and free valve is closed to link its auxiliary power cylinder to its main power cylinder, and its two-way control valve is closed. At the same time, the cylinder interlock and free valve can be opened to allow the auxiliary power cylinder to move idly. Steering is done with a very small operating force, fatigue due to such steering is sufficiently reduced, and in the hydraulic pump and power cylinder,
It is possible to avoid increasing the piston pressure-receiving area, and to reduce the load on the engine that drives the hydraulic pump as much as possible to improve the fuel consumption rate of the engine. The rise of hydraulic pressure of the power cylinder precedes that of the auxiliary power cylinder by the resistance of the left and right turning hydraulic pipes, and the cutting angle of the front axle is made larger than that of the front and rear axles.
Then, the vehicle turns smoothly, and the pressure oil flowing from the main power cylinder to the auxiliary power cylinder can be directionally controlled by a commercially available two-way control valve, and the pressure oil flowing to the auxiliary power cylinder is controlled. The structure of the directional control valve is very simple and miniaturized, and the hydraulic circuit is simplified.As a result, the device can be manufactured at very low cost, which is very useful and practical for front two-axle vehicles. is there.

[Brief description 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-axis truck,
FIG. 2 is a schematic diagram showing the structure around the front and front and rear wheel shafts in the steering system shown in FIG. 11 ... hydraulic pump, 12 ... main power cylinder, 1
3 ... Auxiliary power cylinder, 14 ... Control
Valves, 15, 16 ... 2-way control valves, 17 ... Cylinder interlock and free valves, 20 ...
Front wheel shaft, 21 ... Front and rear wheel shafts.

Claims (4)

[Claims] 1. A double-acting main power cylinder for steering a pair of frontmost wheel shafts swingably connected to both ends of a front axle, and a pair of swingable main power cylinders swingably connected to both ends of front and rear wheels. It is connected to the front and rear wheel shafts, and the left and right cylinder chambers are correspondingly connected to the left and right cylinder chambers of the main power cylinder by left turn hydraulic pipe and right turn hydraulic pipe, respectively.
A double-acting auxiliary power cylinder that supplements the steering force of the cylinder, and changes the flow rate of pressure oil supplied from the hydraulic pump to the main and auxiliary power cylinders, which is controlled by the steering gear box according to the steering input. A control valve, a two-way control valve arranged in each of the left-turn and right-turn hydraulic pipes, a communication pipe connecting the left-turn and right-turn hydraulic pipes to each other downstream of each of the two-way control valves, and a communication pipe Arranged, and closed when each of the two-way control valves is open to link its auxiliary power cylinder to its main power cylinder,
Also, when each of the two-way control valves is closed, it is opened to short-circuit the left and right cylinder chambers of the auxiliary power cylinder with each other through the communication pipe, and the cylinder for making the auxiliary power cylinder idle. Steering system used in vehicles including interlock and free valves. 2. A steering system used in a vehicle according to claim 1, wherein the main power cylinder and the control valve are integrally formed. 3. A steering system for use in a vehicle according to claim 1, wherein the control valve and the steering gear box are integrally formed. 4. The main power cylinder, control,
A steering system used in a vehicle according to claim 1, wherein the valve and the steering gear box are integrally formed.