JPH0615336B2 - 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 is difficult to perform stationary operation when the vehicle is stopped and steering at a low speed running with an extremely small operating force, and to sufficiently reduce fatigue caused by 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 running, which does not require supply capacity, a large load was applied to the engine, and small fuel consumption tended 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 a low speed, the auxiliary cylinder is interlocked with the power steering by the opening / closing valve, and when the vehicle travels at a medium or 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 stationary steering and fine speed running with an extremely small operating force without increasing the size of the hydraulic pump or increasing the pressure receiving area of the power piston. Fatigue is sufficiently reduced, and the load on the engine that drives the hydraulic pump is minimized to maximize the fuel consumption rate of the engine. Also, it is possible to use a commercially available directional control valve and manufacture at low cost. The purpose is to provide the steering system used in the vehicle.

In connection with the above-mentioned problems, the steering system used in the vehicle of the present invention includes a main power cylinder for steering a pair of front wheel axles swingably connected to both ends of the front axle and front and rear axles. An auxiliary power cylinder connected to one of a pair of front and rear wheel shafts swingably connected to both ends and one of the pair of frontmost wheel shafts to supplement the steering force of the main power cylinder, and steering according to a steering input. -A control valve that is controlled by a gear box and changes the flow rate of pressure oil supplied from the hydraulic pump to its main and auxiliary power cylinders, and the left and right cylinder chambers of the auxiliary power cylinder are connected to that control valve. A two-way control valve disposed in each of the left-turn hydraulic pipe and the right-turn hydraulic pipe, and the left-turn and right-turn valves downstream of the two-way control valve. A connecting pipe connecting the hydraulic pipes to each other, and arranged in the connecting pipe, and each of the two-way control valves is closed when the auxiliary power cylinder is linked to the 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,
It 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.

1st and 2nd has shown Example 10 of the steering system used for the vehicle of this invention applied to the front biaxial type truck 72. As shown in FIG.

The steering system 10 includes a front two-axis truck 7
2, the front wheel shaft 20 and the front and rear wheel shafts 21 whose steering angles can be changed in association with each other are steered, and the hydraulic pump 11, the double-acting main power cylinder 12 that steers the front wheel shaft 20, and the 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 side of the main power cylinder 12, and a steering input,
Controlled by the steering gear box 55, from its hydraulic pump 11 to its main and auxiliary power cylinders 1.
The control valve 14 for changing the flow rate of the pressure oil supplied to the control valves 1 and 2 and the cylinder chambers 32 and 33 on the left and right of the auxiliary power cylinder 13 are controlled by the control valve 1
Left turn hydraulic line 68 and right turn hydraulic line 69 connected to 4
To the two-way control valves 15 and 16 respectively arranged in each of the two-way control valves 15 and 16 and the communication pipes 70 that connect the left-turning and right-turning hydraulic pipes 68 and 69 to each other downstream of the two-way control valves 15 and 16, respectively. Placed and part 2
Each of the directional control valves 15, 16 is closed when open to bring its auxiliary power cylinder 13 into communication with its main power cylinder 12, and each of its two-way control valves 15, 16 is closed. When the auxiliary power cylinder 13 is opened, the left and right cylinder chambers 32 and 33 of the auxiliary power cylinder 13 are not connected to the oil reservoir 64, and the communication pipe 70 connects the left and right cylinder chambers 32 and 33 of the auxiliary power cylinder 13 to each other. It includes a cylinder interlock and free valve 17 that short-circuits and idles the auxiliary power cylinder 13, and the truck 72 is stopped or run at a very low speed. At that time, the two-way control valve 15, 1
6 is opened and at the same time, its cylinder interlock and free valve 17 is closed to link its auxiliary power cylinder 13 with its main power cylinder 12 and its track 72 under conditions other than those mentioned above. As it travels down, its two-way control valves 15, 16 are closed and at the same time its cylinder interlock and free
The valve 17 is opened so that the left and right cylinder chambers 32 and 33 of the auxiliary power cylinder 13 are short-circuited to each other by the communication pipe 70, 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, since the hydraulic pump 11 is configured substantially the same as the existing hydraulic pump, the description of the configuration will be 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 3 on the frontmost wheel shaft 20 side and the operation rod 24 end to the chassis 75 side of the truck 72.

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. Change the rudder angle of 73.

That is, the knuckle 18 including the frontmost wheel shaft 20
Like the knuckle in the existing front two-axle truck, the knuckle arm 40 and the tie rod arm 41 are respectively provided in a substantially L-shape, and the knuckle 18 thus configured has the front axle 80. Of the idle arm 36, which are rotatably disposed on both ends of the knuckle arm 40, respectively, and rotatably connected to the chassis 75 of the knuckle arm 40 through a drag link 38. Connected to.

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 and an operating rod 31 having the other end connected to the piston 30. The other end of the cylinder 29 is connected to the idle wheel 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 substantially the same as the idle arm 36 on the frontmost wheel shaft 20 side described above.
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 75 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 right turn pressure port 5
0 is the left turn ports 27, 34 of the main and auxiliary power cylinders 12, 13 via the left turn hydraulic pipes 66, 68.
The right turn pressure port 51 is connected to the right turn hydraulic piping 67, 69.
Through its main and auxiliary power cylinders 12, 13
To the right turn ports 28 and 35 of the oil reservoir 6 via the hydraulic return pipe 71.
4 are connected 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 control valve 14, and turn left and right hydraulic pipes 6.
8 and 69 are arranged respectively.

The two-way control valves 15 and 16 include control valve ports 58 and 60 connected to the respective spool chambers and an 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. It is configured such that it is excited when the vehicle is traveling at a low speed, and is not excited when the track 72 is traveling under other conditions.

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 connects and disconnects the ports 62 and 63. So as to reciprocally slide 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, and when the electromagnetic coil is illustrated, 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 biaxial truck 72 including the steering system 10 will be described.
When the vehicle is stopped at 2
The respective electromagnetic coils of the directional control valves 15 and 16 and the electromagnetic coils of the cylinder interlock-and-free valve 17 thereof are excited, and the control coils of the two-way control valves 15 and 16 are controlled. The valve ports 58 and 60 are the auxiliary power cylinders.
The cylinder interlock and free valve 17 is connected to the ports 59 and 61, respectively, and the pair of ports 62 and 63 is cut off in the cylinder interlock and free valve 17.

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 720 is traveling at a very low 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 small fuel ratio 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, that is, a so-called idling state. That is, such steering during traveling is performed only by the main power cylinder 12, and at that time, the cylinder interlock and free valve 17 is opened and the auxiliary pipe 70 is used for the auxiliary operation. Since the cylinder chambers 32 and 33 of the power cylinder 13 are short-circuited to each other, the auxiliary power cylinder 13 is
It is idled and follows its steering with its main power cylinder 12 without substantially resisting it.

Of course, in the above steering,
When the wheel 54 is in the neutral position, the pump port 49 of the control valve 14 is connected to its reservoir port 52 and the hydraulic fluid from its hydraulic pump 11 is returned to its oil reservoir 64.

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 will be understood from the above, the steering system used in the vehicle of the present invention comprises a main power cylinder for steering a pair of front wheel axles swingably connected to both ends of the front axle, and a front and rear axle. A power cylinder that is connected to one of a pair of front and rear wheel shafts that are swingably connected to both ends and one of the pair of frontmost wheel shafts to supplement the steering force of the main power cylinder, and steering according to the steering input. -A control valve that is controlled by a gear box and changes the flow rate of pressure oil supplied from the hydraulic pump to its main and auxiliary power cylinders, and the left and right cylinder chambers of the auxiliary power cylinder are connected to that control valve. The two-way control valves respectively arranged in the left turn hydraulic pipe and the right turn hydraulic pipe, and the left turn and A connecting pipe connecting the folding hydraulic pipes to each other, and arranged in the connecting pipe, and closed when each of the two-way control valves is opened to interlock the auxiliary power cylinder with the main power cylinder. Also, when each of the two-way control valves is closed, it is opened so that the cylinder chambers on the left and right of the auxiliary power cylinder are not connected to the oil reservoir, and the communication pipe connects the left and right of the auxiliary power cylinder. In the steering system used in the vehicle of the present invention, the two-way control valve includes a cylinder interlock and free valve that short-circuits the cylinder chambers and idles the auxiliary power cylinder. Is opened and at the same time its cylinder interlock and free
With the valve closed to engage its auxiliary power cylinder with its main power cylinder, and its two-way control valve is closed, while its cylinder interlock and free valve is open and its auxiliary It is possible to make the power cylinder run idle,
Steady running when the vehicle is at a standstill and steering at very low speeds are performed with extremely small operating force, and fatigue due to such steering is sufficiently reduced. Such steering can be performed without increasing the pressure receiving area of the power piston, and the load of the engine that drives the hydraulic pump can be minimized to reduce the fuel consumption rate of the engine. Improved, especially with its commercially available two-way control valve from its control valve to its auxiliary power
The hydraulic pressure flowing to the cylinder can be directionally controlled, the valve for controlling the pressure oil flowing to the auxiliary power cylinder is structurally very simple and miniaturized, and the hydraulic circuit is simplified, so that the device is It can be manufactured at a very low cost, making it very useful and practical for large vehicles.

[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 main power cylinder for steering a pair of frontmost wheel shafts swingably connected to both ends of a front axle, and a pair of front and rear wheel shafts swingably connected to both ends of a front and rear axle. And an auxiliary power cylinder that is connected to one of the pair of frontmost wheel shafts to supplement the steering force of the main power cylinder, and is controlled by the steering gear box in response to the steering input, from the hydraulic pump to the main and A control valve that changes the flow rate of pressure oil supplied to the auxiliary power cylinder, and a left turn hydraulic pipe and a right turn hydraulic pipe that connect the left and right cylinder chambers of the auxiliary power cylinder to the control valve, respectively. A directional control valve, 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 the communication pipe Is arranged, and, the auxiliary power cylinder is interlocked to the main power cylinder closed when each of the two directional control valve is opened,
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.