JPS58152665A - Hydraulic apparatus for vehicle - Google Patents

Abstract

PURPOSE:To enable to obtain a constantly stable property of a steering force by providing a bypass tube with a throttle valve on a three-way changeover valve adapted to feed pressure oil selectively to various mechanisms according to a vehicle height adjusting signal as communicating the hydraulic pump side with the power steering mechanism side. CONSTITUTION:Normally, a three-way changeover valve 6 is set to the position of a power steering mechanism 11 for a stable steering while the feeding of oil to the side of a vehicle height adjusting mechanism is cut off. The closing of a check valve 42 checks variation in the hydraulic pressure. When the vehicle height is adjusted to accommodate the load carried, the three-way changeover valve 6 is switched with a controller 30 to feed pressure oil to the side of the vehicle height adjusting mechanism 32 while cutting off it to the side of a power steering mechanism 11. However, the bypass tube 7 ensures the supply of oil in a specified amount with a throttle valve 10 preventing the steering wheel from becoming heavily. In this case, the amount of oil to be fed to the side of the vehicle height adjusting mechanism is reduced but the effect is minimal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic system for a power steering mechanism of a vehicle, etc., which always provides a stable steering force.

In vehicles equipped with a power steering mechanism that uses hydraulic pressure to assist steering force and a vehicle height adjustment mechanism that adjusts changes in vehicle height due to passenger load, etc., a common hydraulic pump may be used. A hydraulic system has been put into practical use that receives a signal related to vehicle height adjustment from a three-way switching valve and selectively supplies pressure oil to cylinders and the like provided in each mechanism.

Conventionally, this type of device is equipped with one hydraulic pump, and selectively supplies pressure oil to the power steering mechanism or suspension side vehicle height adjustment mechanism having a four-way switching valve in the oven center set via the three-way switching valve. The three-way switching valve for supplying pressure oil is normally switched to the power steering mechanism side, and the pressure oil is supplied to the vehicle height adjustment mechanism side. In this case, the time required for supplying pressure oil to the vehicle height adjustment mechanism is several seconds at most, which is considered to pose no practical problem.

However, when pressure oil is supplied to the vehicle height adjustment mechanism even for a few seconds, the supply of pressure oil to the power steering mechanism is stopped. Therefore, when such switching occurs during steering, no steering force is applied by the power steering mechanism, and the steering wheel becomes heavy. Furthermore, when the steering wheel is rotated against such weight, negative pressure is generated in the cylinder provided in the power steering mechanism, and as a result, the vehicle height adjustment is completed and the three-way switching valve is switched to the power steering mechanism side. When switching to , a reaction shock occurs based on the negative pressure.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hydraulic system for a vehicle, such as a power steering mechanism, which eliminates the above-mentioned disadvantages and always provides a stable steering force.

In order to achieve the above object, the present invention is applied to a hydraulic system having a hydraulic pump shared by a vehicle height adjustment mechanism and an open center power steering mechanism; The present invention is characterized in that a three-way switching valve for selectively supplying pressurized oil to each of the mechanisms is provided with a bypass pipe having a throttle valve that communicates the hydraulic pump side with the power steering mechanism side.

Hereinafter, a preferred embodiment to which the present invention is applied will be described in detail with reference to the drawings.

The drawing shows one embodiment of the present invention, and is a system diagram of a power steering mechanism and a vehicle height adjustment mechanism of a vehicle.

In the figure, 1 indicates a hydraulic system. The hydraulic system 1 includes a hydraulic pump 2. The suction side of the hydraulic pump 2 is connected to the oil passage 4 through an oil passage 3, and the discharge side thereof is connected to an oil passage 5.
The branch oil passage 5a branches on the downstream side of the three-way switching valve 60.
Connect to the input end. On the other hand, 7 is a bypass pipe provided according to the present invention, which branches off from the oil passage 5 described above. In addition, the three-way switching valve is connected. A throttle valve 10 is installed in the middle of the bypass pipe 7 to adjust the flow rate of the pressure oil passing through the bypass pipe 7. In the embodiment, the discharge amount of the hydraulic pump 2 is is 5t
/min, and the pressure oil passing through the bypass pipe 7 is set to about 1/2 to 1/3 of the discharge amount of the hydraulic pump, but it can be set arbitrarily depending on the type of mechanism. Note that the bypass pipe 7 is formed with the same diameter as a normal oil passage, and the flow rate is adjusted with a throttle valve 10, but it is of course possible to use a small diameter pipe without using a throttle valve. . In this case, it is necessary to consider fluctuations in flow rate due to changes in oil viscosity due to external temperature, etc.

On the other hand, the downstream side of the oil passage 9 is connected to an oil supply end 13 of an open center four-way switching valve 12 provided on the power steering mechanism 11 side, and its discharge end 14 is connected to a tank 16 via an oil passage 15.

Further, load ends 17 and 18 of the four-way switching valve 12 are connected to both ends of the cylinder 210 via oil passages 19 and 20, respectively. This four-way switching valve 12 is a known type having a valve 22 inserted therein, and the valve 22 is controlled by a handle 23. A piston 25 is slidably inserted into the cylinder 21 approximately in the middle thereof, and racks 26 are provided on both sides of the piston 250, respectively.

Since the power steering mechanism 11 is an open center set when the handle 23 is in the neutral state, all the pressure oil supplied to the oil supply end 13 of the four-way switching valve 12 is discharged to the discharge end 14. When the rotation operation is performed in one direction, the valve 22 is displaced following the rotation operation, and the pressure oil supplied from the oil supply end 13 is discharged from one load end, thereby displacing the piston 25 in one direction. The driving displacement of the tip assists the steering force, and when the handle 23 is rotated in the other direction, pressure oil is discharged from the other load end, and the piston 25 operates to move in the other direction. The above is the system configuration of the power steering mechanism 11.

1. The other end of the output side of the three-way switching valve 6 is connected to the upstream side of the oil passage 27, and the downstream side thereof is connected to the oil passage 28 and the oil passage 29 at a confluence point 29a.

Therefore, as described above, the three-way switching valve 6 has the hydraulic pump 1 connected to its input side, the power steering mechanism 11 side connected to one output side end, and the vehicle height adjustment mechanism 27 side connected to the other output side end. It turns out. The three-way switching valve 6 is driven and controlled by a solenoid 31 controlled by a control device 30, and the pressure oil supplied to the input side of the three-way switching valve 6 is selectively directed to one end of the output side or the other end of the output side. Exhale.

Next, the vehicle height adjustment mechanism 32 will be explained. Said oil path 2
The downstream side of 9 branches at branch point 33, and on the other hand) branch oil path 3
4 is connected to the right suspension unit 35, and the other branch oil passage 36 is connected to the other left suspension unit 3.
7 to vc-bond. In the figure, numerals 38 and 39 indicate wheels installed on the suspension unit, and 40 and 41 indicate fitting bases.

Further, the downstream side of the oil passage 28 is connected to an input end of a four-check valve 420, and the output end thereof is connected to a tank 44 via an oil passage 43. Note that the check valve 42 is driven by a valve nozzle 45 controlled by the control device 30.

47 is a stabilizer, with both ends attached to the suspension unit side and a movable link 4 attached to the middle part.
8 in proportion to the vehicle height, and a position sensor 46 for detecting the positional displacement of the movable link 48 is provided on the fitting base side. Reference numerals 49 and 50 in the figure are the fulcrums of the suspension link 47. .Also,
The position sensor 46 converts the position into an electrical signal using, for example, a differential transformer or the like, and its output is configured to be input to the control device 30 via the connection line 51.

Therefore, changes in vehicle height are detected by the position sensor 46 at the switching valve 6.
and supplies pressure oil from the hydraulic pump 1 to the suspension system on the vehicle height adjustment mechanism side to raise the vehicle height and lower the vehicle height (if necessary, drive the check valve 42). to open the valve and discharge oil from the suspension/con unit.

The operation of the hydraulic system that drives the power steering mechanism and the vehicle height adjustment mechanism as described above is such that the three-way switching valve 6 is normally switched to supply oil to the power steering mechanism 11 side, and the vehicle height adjustment mechanism 32
Since the oil supply to the side is cut off and the function is stably performed, and the check valve 42 is also closed, the oil pressure on the side of the vehicle height adjustment mechanism 32 does not fluctuate.

On the other hand, when the passenger load, etc. increases and the vehicle height becomes low, and the vehicle height should be increased, the three-way switching valve 6 is switched by the control device 30 as described above, and pressure oil is supplied to the vehicle height adjustment mechanism 32 side. The oil supply from the three-way switching valve 6 to the power steering mechanism 11 side is cut off. However, the three-way switching valve 6
A bypass pipe 7 is provided to communicate between the hydraulic pump side and the power steering mechanism side, and a predetermined amount of pressure oil is constantly flowing through the throttle valve 10 to constantly supply oil to the power steering mechanism side, so when adjusting the vehicle height. In this case, the steering wheel will not become heavy (or shock will occur).In addition, in this case, the amount of oil supplied to the vehicle height adjustment mechanism side will be reduced by providing a bypass pipe, but this mechanism will not be as heavy as the power steering mechanism. The effect is minimal as it operates with a small amount of oil.

In the figure, reference numeral 52 is an ignition key, 53 is a delay switch, and 054 is a battery that drives the control device 30 and the like, which has a function of turning off after a predetermined period of time has passed after the ignition key is turned off.

In the above embodiments, the hydraulic system common to the power steering mechanism and the vehicle height adjustment mechanism was explained, but other mechanisms such as a power brake mechanism can be added as appropriate, and a pressure pump using a predetermined fluid can be used as well. It is possible to implement it.

As is clear from the above description, the hydraulic system according to the present invention exhibits the advantage of constantly applying a stable steering force without affecting the power check mechanism even when the vehicle height is adjusted.

[Brief explanation of drawings]

The drawing shows one embodiment of the present invention, and is a system diagram of a power steering mechanism and a vehicle height adjustment mechanism of a vehicle. In the drawing, 6 is a three-way switching valve, 7 is a bypass pipe, and 10 is a throttle valve. Patent applicant Honda Motor Co., Ltd.

Claims (1)

[Claims] In a vehicle hydraulic system having a hydraulic pump shared by a vehicle height adjustment mechanism and an open center power steering mechanism, a signal related to vehicle height adjustment is obtained from the vehicle height adjustment mechanism and pressure oil is selectively supplied to each of the mechanisms. A hydraulic system for a vehicle, characterized in that a three-way switching valve is provided with a bypass pipe having a throttle valve communicating between the hydraulic pump side and the power steering mechanism side.