JPH039444Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a vehicle height adjustment device, and particularly to a vehicle height adjustment device as a hydroneumatic suspension system for a vehicle.

<Prior art> A vehicle height adjustment device as a hydroneumatic cylinder system enables communication and isolation between a plurality of accumulators communicating with a hydraulic suspension cylinder using a spring characteristic switching valve, and If the damping force generated when the cylinder expands and contracts can be changed by damping force switching valves, and each switching valve is configured to be switched by an electric actuator, the applicable By operating the actuator, spring characteristics and damping force dynamics can be selected, and desired vehicle height adjustment can be achieved electrically.

<Problems to be solved by the present invention> However, if a solenoid is used as an electric actuator, the solenoid must be made large enough to withstand being energized for a long time, resulting in consumption. There is a disadvantage that the amount of electric power increases.

In addition, there are two types of solenoids: sliding type and rotating type, but when using a sliding type solenoid, it has to have a large stroke to ensure reliable switching, which has the disadvantage of making it larger. Additionally, when using a rotary solenoid, it is difficult to stabilize the rotation angle and reliable switching is not possible.

Therefore, in view of the above-mentioned circumstances, the present invention has been devised so that the spring characteristic switching valve and the damping force switching valve can be switched without using a solenoid as an electric actuator and without providing a special hydraulic power source. The object of the present invention is to provide a vehicle height adjustment device having a new configuration.

<Means for solving the problems> In order to solve the above problems, the configuration of the present invention is as follows.
A hydraulic suspension cylinder, a plurality of accumulators communicating with the hydraulic suspension cylinder, a damping force switching valve switchably provided between the hydraulic suspension cylinder and the accumulator, and a spring switchably provided between the plurality of accumulators. The damping force switching valve has a soft position and a hard position, and the spring characteristic switching valve has a communication valve. Each pilot switching valve has a supply position, a blocking position, and a holding position, and each pilot pressure is supplied from the internal pressure of at least one accumulator isolated by the spring characteristic switching valve. This is characterized in that the damping force switching valve and the spring characteristic switching valve are switched to arbitrary positions by supplying the damping force switching valve to the supply position of the pilot switching valve.

<Example> The present invention will be described below based on the illustrated embodiment. FIG. 1 is a system diagram showing an example of a vehicle height adjustment device according to the present invention. It has a plurality of accumulators 2 and 3 communicating with the hydraulic suspension cylinder 1, and has a spring characteristic switching valve 4 between the plurality of accumulators 2 and 3, and also has a spring characteristic switching valve 4 between the accumulator 2 and the hydraulic suspension cylinder 1. In between, there is provided a damping valve 5 and a damping force switching valve 6 parallel to the damping valve 5.

The hydraulic suspension cylinder 1 has a piston rod whose tip end is connected to the vehicle body side and whose lower end is connected to the wheel side. When oil flows into the piston side oil chamber 12 through the piston rod 13, the piston rod is expanded by obtaining a thrust based on the effective pressure receiving area of the piston rod and changes in the internal pressure of the accumulators 2 and 3. In addition, at this time, cylinder 10
The oil in the rod side oil chamber 14 is transferred to the piston side oil chamber 12.
The piston portion 11 moves to the piston portion 11 as appropriate through the passage.

Furthermore, the above hydraulic suspension cylinder 1
The supply of pressure oil to the vehicle height adjustment device including the vehicle height adjustment device is performed by an oil pump P connected to the main passage 1a.

The plurality of accumulators 2 and 3 each have bellows 20 and 30 inside, and the bellows 20 and 30 define gas chambers 21 and 31 and oil chambers 22 and 32, respectively. The oil chambers 22 and 32 of each of the accumulators 2 and 3 are communicated with each other by a passage, and the spring characteristic switching valve 4 is disposed in the passage. .

The spring characteristic switching valve 4 is in a communication position 40.
and a cutoff position 41, and normally in the communication position 40, the communication between the plurality of accumulators 2, 3, that is, the respective oil chambers 22, 3.
This allows the two to communicate with each other and provides low spring characteristics. And, when activated, the cutoff position is 4.
1 to cut off communication between the respective oil chambers 22 and 32 and obtain high spring characteristics. Further, in this embodiment, the operation of the spring characteristic switching valve 4 to the above-mentioned shutoff position 41 is performed by supplying pilot pressure via a pilot passage 4a whose one end is connected to the spring characteristic switching valve 4. It is said to be due to

The damping valve 5 includes a rebound damping valve 50 that generates a damping force on the rebound side of the hydraulic suspension cylinder 1, and a compression damping valve 51 that generates a damping force on the compression side. In this example,
Although the damping valve 5 is said to be a back pressure valve, it may be a damping valve that allows generation of other desired damping force. Further, in this embodiment, a compression side damping valve 51 is also provided in addition to the expansion side damping valve 50, but instead of this, the expansion side damping valve 5
It may be only 0. Further, in this embodiment, the damping valve 5 is connected to the hydraulic suspension cylinder 1, the accumulator 2,
However, instead of this, it is arranged in the hydraulic suspension cylinder 1 communicating with the main passage 1a, particularly in the piston portion 11. It may be set. In this case, it goes without saying that the damping valve disposed in the piston portion 11 can be any damping valve that generates a damping force related to the so-called orifice characteristic, valve characteristic, boat characteristic, or a combination of these characteristics. It is.

The damping force switching valve 6 changes the flow resistance related to the main passage 1a and also changes the damping force generated by the damping valve 5. In this embodiment, it can be switched in multiple stages, that is, in three stages. It is formed in In this embodiment, the damping force switching valve 6 is composed of two switching valves 60 and 61, each having two positions 62, 63, 64, and 65, except for one position 65. Positions 62, 63, and 64 have orifices 6
2', 63', 64' are formed, and each orifice 62', 63', 64' has a different diameter. In addition, one switching valve 60
is in the so-called soft state position 63, which normally has the orifice 63' with the largest diameter.
Only during this operation is a switch to a so-called hard position 62 having an orifice 62' of intermediate diameter. The other switching valve 61 is normally in a so-called communication state position 65 that simply allows oil to pass through, and is in a so-called ultra-hard state position 64 that has an orifice 64' with the smallest diameter only when it is activated. It can be switched to

In the embodiment shown in FIG. 1, the damping force switching valve 6 can generate a damping force with orifice characteristics.
Three stages of damping force are generated, and the above-mentioned damping valve 5 may be omitted if the damping force only needs to be changed based on the orifice characteristics.

In this embodiment, one end of the switching operation of the two switching valves 60, 61 is
This is done when pilot pressure is supplied via the pilot passages 60a, 61a connected to the first.

At each other end of the pilot passage 4a, one end of which is connected to the pilot passages 60a, 61a and the spring characteristic switching valve 4, there is provided a pilot solenoid valve 7, which is a pilot switching valve, in the embodiment shown in FIG.
8 and 9 are connected. Each of the pilot solenoid valves 7, 8, 9 has a supply position 70, 80, 90 that enables the supply of pilot pressure to the respective pilot passage 4a, 60a, 61a, and also has a ，
It has cutoff positions 71, 81, 91 that allow release of the supply of pilot pressure to 61a, and
holding positions 72, 82, which make it possible to maintain the state in which pilot pressure is supplied to each pilot passage 4a, 60a, 61a or the state in which it is released;
92. Furthermore, each of the pilot solenoid valves 7, 8, and 9 is connected to one end of a pilot pressure supply passage L that supplies a desired pilot pressure, and when the supply of the pilot pressure is released, the oil is removed. An unload passage U is connected to the tank T to return it to the tank T.

In addition, each of the above-mentioned pilot passages 4a, 60a, 6
1a is the other hydraulic suspension cylinder 1 (for example, the right side hydraulic suspension cylinder (not shown)) which is parallel to the one side (for example, the right side hydraulic suspension cylinder 1).
The spring characteristic switching valve 4 and the damping force switching valve 6' are respectively connected to the spring characteristic switching valve 4 and the damping force switching valve 6'.

In the present invention, the other end of the pilot pressure supply passage L is connected to the plurality of accumulators 2 and 3. That is, in the present invention, the plurality of accumulators 2 and 3 are used as a source of the desired pilot pressure. In the embodiment shown in FIG. 1, the spring characteristic switching valve 4 communicates with the accumulator 3 which is cut off from communicating with the hydraulic suspension cylinder 1 side. This is advantageous in that the influence of the dynamic pressure of the cylinder 1 does not appear as fluctuations in the pilot pressure and is stable, and the hydraulic pressure in a relatively low range can be set to the pilot pressure. In addition, instead of this, the pilot pressure supply passage L' is connected by another passage L so as to communicate with the accumulator 2 which is always communicated with the hydraulic suspension cylinder 1 side regardless of the operation of the spring characteristic switching valve 4. In this case, oil pressure ranging from a low oil pressure range to a high oil pressure range can be used as the pilot pressure.

Therefore, in the vehicle height adjustment device described above, if the spring characteristic switching valve 4 is set to the communicating position 40, the plurality of accumulators 2 and 3 are communicated with each other, and the spring characteristic when the hydraulic suspension cylinder 1 expands and contracts is , because two volumes of accumulators 2 and 3 act on the same stroke, it becomes a so-called soft stroke, and the pilot solenoid valve 7 is turned on.
When the operation is performed to switch to the supply position 70, the communication between the plurality of accumulators 2 and 3 is cut off, and the spring characteristics during expansion and contraction in the hydraulic suspension cylinder 1 are such that one volume of the accumulator 2 acts for the same stroke. That's why it's so-called hard.

Then, as described above, the pilot solenoid valve 7 is energized to switch to the supply position 70 and the spring characteristic switching valve 4 is set to the cutoff position 41, and if you wish to maintain that state, energize the pilot solenoid valve 7. When released, the pilot solenoid valve 7 is switched to the holding position 72, allowing the hard state of the spring characteristics to continue.

In addition, the spring characteristic switching valve 4 is set to the communication position 4.
To return to zero, the pilot solenoid valve 7 is energized and switched to the discharge position 71.
As a result, the pilot pressure supplied to the spring characteristic switching valve 4 is released, and the spring characteristic switching valve 4 returns to the communication position 40.

In addition, when changing the damping force generated by the damping force valve 5 when the hydraulic suspension cylinder 1 expands and contracts, for example, when changing from a soft state to a hard state, the pilot solenoid valve 8 is used.
The damping force switching valve 60 is switched to another position 62 by energizing the damping force switching valve 60 to a position 80 where the damping force is supplied. As a result, the oil in the main passage 1a communicating with the hydraulic suspension cylinder 1 passes through the orifice 62' having a medium diameter, and the desired hard damping force can be obtained. And when maintaining the state,
The power supply to the pilot solenoid valve 8 is removed and the holding position 82 is returned.

Further, in order to change from the soft state to the super hard state, it is sufficient to perform the same operation on the pilot solenoid valve 9 as the above-mentioned operation on the pilot solenoid valve 8. In order to return either of the switching valves 60, 61 to their original states, that is, the soft state position 63 and the communicating state position 65, the pilot solenoid valves 8, 9 should be moved to the discharge position 8.
It is sufficient to energize the switching valves 60 and 91 and release the pilot pressure supplied to each switching valve 60 and 61. After the pilot pressure has been released, if the power supply to each pilot solenoid valve 8, 9 is stopped, the holding position 82, 92 is returned to, and the pilot pressure released state can be continued.

In the embodiment shown in FIG. 1, the damping force switching valve 6 is said to be composed of two switching valves 60 and 61, but it may be one switching valve having three positions 62, 63, and 64. It is also good to do
In this case, only one of the pilot solenoid valves 8, 9 needs to be provided.

Next, another embodiment shown in FIG. 2 will be explained. In the previous embodiment, the pilot pressures for the spring characteristic switching valves 4, 4' and the damping force switching valves 6, 6' are controlled by the same hydraulic suspension. Since the oil is drawn from the accumulator 3 on the cylinder 1 side, when these pilot pressures are used, the pressure oil in the accumulator 3 on one side (for example, the right side) is consumed, so that the pressure oil is supplied to the hydraulic suspension cylinder 1' on the other side (for example, the left side). There is a risk of an imbalance in the amount of oil involved, but in order to eliminate this
As shown in the figure, the pilot line L1 from one (for example, the right side) accumulator 3 is connected to the left and right damping force switching valves 6, 6', and the pilot line L2 from the other (for example, left side) accumulator 3 is connected to the left and right springs. By connecting to the constant switching valves 4, 4', the control of the left and right valves can be synchronized, and the control of the left and right suspension cylinders 1, 4' can be synchronized.
1' is constructed to prevent an imbalance in the amount of oil involved and to eliminate the phenomenon of difference in level between the left and right sides.

<Effects of the invention> According to the invention, the spring characteristic switching valve and the damping force switching valve are switched by the supply and release of pilot pressure, respectively, and the pilot pressure is controlled by the pilot pressure to supply, release and maintain the pilot pressure. Since there is no need to continuously energize the solenoid valve, there is no need to increase the size of the solenoid and the resulting increase in power consumption.
This has the advantage that the solenoid can be made smaller.

Furthermore, since the pilot pressure for switching the spring characteristic switching valve and the damping force switching valve is supplied from one of the plurality of accumulators as a hydraulic pressure source, another hydraulic pressure source such as a pilot pump etc. This eliminates the need for special arrangement of the system, which has the advantage of being economically advantageous.

Furthermore, the pilot line should be configured to reduce the influence of fluctuating pressure in the hydraulic suspension cylinders, or to maintain a balance so that there is no difference in the amount of oil involved in the left and right hydraulic suspension cylinders. It is also easy to make and has excellent practical advantages.

Furthermore, even if the stroke of the spring characteristic switching valve and the damping force switching valve is long, there is no problem since the stroke is based on the pilot pressure. Moreover, there is an advantage that it is possible to reliably switch between the two.

[Brief explanation of drawings]

FIGS. 1 and 2 are system diagrams showing other embodiments of the vehicle height adjustment device according to the present invention. 1, 1'...Hydraulic cylinder, 2, 2', 3, 3'
...Accumulator, 4,4'...Spring characteristic switching valve, 5,5'...Damping force valve, 6,6'...Damping force switching valve, 7,8,9...Pilot solenoid valve, 4
a, 60a, 61a...Pilot passage, L'...
Pilot pressure supply passage, L...passage, 1a...main passage, 1a'...bypass, P...oil pump, T...tank.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A hydraulic suspension cylinder, a plurality of accumulators communicating with the hydraulic suspension cylinder, and a damping force switching valve switchably provided between the hydraulic suspension cylinder and the accumulator. , has a spring characteristic switching valve that can be freely switched between a plurality of accumulators, and a plurality of pilot switching valves that respectively switch between a damping force switching valve and a spring characteristic switching valve, and the damping force switching valve has a soft position and a hard position. position, the spring characteristic switching valve has a communicating position and a shutoff position, and each pilot switching valve has a supply position, a shutoff position, and a holding position;
The damping force switching valve and the spring characteristic switching valve can be switched to arbitrary positions by supplying pilot pressure from the internal pressure of at least one accumulator isolated by the spring characteristic switching valve to the supply position of each pilot switching valve. Features a vehicle height adjustment device. (2) The pilot pressure of one of the spring characteristic switching valve and the damping force switching valve supplies the internal pressure of the accumulator on the left or right hydraulic suspension cylinder side, and the pilot pressure of the other supplies the internal pressure of the accumulator on the remaining hydraulic suspension cylinder side, respectively. The vehicle height adjustment device according to item 1 of the scope of utility model registration, which is arranged so as to act as a source.