JPS60248412A - Suspension apparatus for car - Google Patents

Abstract

PURPOSE:To prevent the deterioration of drive feeling and steering stability of a car by installing a pressure adjusting valve for controlling the antinose-dive action and a damping valve for sealing oil into a rod-side oil chamber in inoperative state, thus damping the road-surface vibration. CONSTITUTION:A hydraulic cylinder 1 is arranged at right and left on the front- wheel side of a car and is equipped with a piston part 1c for dividing the inside of the cylinder 1a into a rod-side oil chamber A and a piston-side oil chamber B. Oil is discharged from the hydraulic cylinder 1 into a reservoir tank 5 through a passage 6, which communicates to a passage (b) through a check valve 9, onto which a pressure adjusting valve 9 is installed. A damping valve 10 is arranged into the rod cover part 1e of the cylinder 1, and when the antinose-dive function is to be developed, the valve 10 is put into inoperative state, and the flow-out of the oil in the oil chamber A into the passage 6 is suppressed, and the flow-out of the oil in the oil chamber B to the outside is suppressed by the valve 9, and the generation of the nose-dive phenomenon is prevented.

Description

[Detailed Description of the Invention] The present invention relates to a vehicle suspension system, and particularly to a vehicle suspension system that is ideal for equipping special vehicles such as latte lane vehicles and crane vehicles. Regarding equipment.

[Conventional technology]

Suspension systems for vehicles such as love terrain vehicles and crane vehicles that lift heavy objects and perform work such as rearranging them at work sites, etc., use their hydraulic cylinders when lifting heavy objects. It is designed to maintain the suspension spring in the maximum compression state and to disable the suspension spring, that is, to maintain the compression, and it is capable of running on high-speed roads like a normal vehicle, and is stable in running. It is preferable that the structure is formed so as to improve performance and riding comfort.

In other words, when the vehicle is running normally with the compression holding function that puts the suspension springs in an inactive state released and the suspension springs are activated, the suspension springs absorb road vibrations, and are useful for vehicles with short wheel bases such as latte lane vehicles. In the case of
It is preferable that the suspension device is configured so as to exhibit an anti-nose dive function that prevents a nose dive phenomenon when applying a brake to the vehicle.

[Problem that the invention seeks to solve]

However, conventional suspension systems do not have a buffering function to dampen road vibrations absorbed by the suspension gears, resulting in poor ride comfort and poor running stability, making it difficult to drive at low speeds with a maximum speed of about 43 km/A. The problem was that it was limited.

In addition, when the anti-nose dive function is activated when the brakes are operated while the vehicle is running, and the hydraulic cylinder is completely locked, road vibrations are transmitted directly to the vehicle frame, resulting in extremely poor ride comfort and the risk of driving over a bump. When there is an upward thrust from below the spring, the impact is directly transmitted to the vehicle body frame, and there is a risk that the handling stability of the vehicle may also be deteriorated.

SUMMARY OF THE INVENTION Accordingly, the present invention provides a suspension system for a vehicle that is formed to exhibit a compression holding function, which exhibits a buffering function to attenuate road vibrations absorbed by suspension springs when the vehicle is normally running on a road surface, and also provides The purpose of the present invention is to provide a suspension system for a vehicle that can exhibit an anti-nose dive function without deteriorating comfort or handling stability.

[Means for solving problems]

In order to solve the above problems, the present invention has a structure that includes a suspension spring and a hydraulic cylinder between a vehicle body frame and a wheel, compresses the hydraulic cylinder, and changes the compression state of the hydraulic cylinder. In a vehicle suspension system configured to hold the suspension spring in an inoperative state, the suspension system is activated during a pressure stroke of a hydraulic cylinder when a brake is applied to the vehicle, thereby causing the suspension spring to remain inactive. It has a pressure regulating valve formed to be able to control the anti-nose dive action, and also enables the generation of extension side damping force at least during the extension stroke of the hydraulic cylinder, and when the hydraulic cylinder is not in operation, it prevents oil from flowing into the rod side oil chamber. A particular feature of the invention is that it includes a damping valve configured to permit containment of the air.

〔Example〕

The present invention will be explained below based on the illustrated embodiments.

Figure 1 shows a suspension system for a vehicle according to an embodiment of the present invention, in which pressure oil from a main pump 2 is supplied to a hydraulic cylinder 1 via a main solenoid valve 3 and a passage 4. At the same time, oil is discharged from the hydraulic cylinder 1 to a reservoir tank 5 via a passage 6.

The hydraulic cylinders 1 are disposed on the left and right sides of the front wheels of the vehicle, and their upper ends are connected to the body frame of the vehicle, and their lower ends are connected to the wheels of the vehicle. The hydraulic cylinder 1 has a piston part IC that is disposed at the tip of a piston rod 16 inserted into the cylinder 1α and partitions the inside of the cylinder 1α into a rod-side oil chamber A and a piston-side oil chamber B. ing.

The piston portion 1cvc is provided with a check valve 1d that prevents oil from flowing from the rod-side oil chamber A into the piston-side oil chamber B.

The main solenoid valve 3 has a supply position 3α for supplying pressure oil from the main pump 2 into the passage 4, and a discharge position 3α for discharging the oil supplied to the passage 4 into the reservoir tank 5. It has position 3h.

At this discharge position 36, pressure oil can be supplied to the power steering mechanism PS (not shown) of the vehicle. Further, the main pump 2 is provided with a relief valve 2α.

The passage 4 is connected to a check valve 7 disposed on the rod cover part 1e of the hydraulic cylinder 1, and the pressure oil inserted when the check valve 7 is opened is passed through the passage 7a to the rod side oil. It is designed to flow into room A. In this embodiment, the check valve 7 is composed of a steel ball 70 and a spring 71 that biases the steel ball 70.

The passage 6 has a suction valve 6α at its reservoir tank 5 side end.
and the back pressure valve 6 in parallel, and is formed so that return oil from the power steering mechanism PS of the vehicle flows therein.

The return oil and the action of the back pressure valve 66 improve the ability of oil to be sucked into the hydraulic cylinder 1.

Further, the passage 6 is connected to a passage connected to the piston-side oil chamber B via an operating check valve 8 disposed on the rod cover portion 1e. That is, the passageway 8a is connected to the passageway 8a, the passageway 8α is connected to the passageway 8h via the operating check valve 8 which is in an open state, and the passageway 8h is connected to the passageway 6. This is what is being done. In this embodiment, the operated check valve 8 includes a plunger 80 that slides with pressure oil, a steel pole 81 that is opened by sliding of the plunger 80, and a steel ball 81 that energizes. It consists of a spring 82. Then, when the supply of pressure oil to the plunger 80 is released, it becomes a check valve and blocks communication between the passages 8a and 86.

The passage 6 is also connected to the other passages through a check valve 9, allowing oil to pass from the passage 6 side to the passage side, but conversely from the passage 6 side to the passage 6 side. It is not possible for oil to pass through. The check valve 9 is
It has a valve body 91 energized by a spring 90, and the tip of the valve body 91 closes the opening of the passage 9a communicating with the passage 6. Furthermore, the valve body 91 includes:
A through hole 92 that communicates the back pressure side of the valve body 91 with the passage z side.
is drilled.

As a result, when the inside of the piston-side oil chamber B becomes almost negative pressure, that is, during the extension stroke of the hydraulic cylinder 1, the valve body 91 overcomes the spring 90 and retreats, moving from the passage 6 side into the piston-side oil chamber B. of oil can be inhaled.

Note that the operated check valve 8 has the same function as the check valve 9, so if the operated check valve 8 is made larger to increase oil flow, as shown in Figure 2, the arrangement of the check valve 9 can be improved. The settings can be omitted. Furthermore, the operated check valve 8 shown in Fig. 2 consists of a plunger 80 and a spring 82 that urges the plunger 80 from behind. It is formed so that a pilot pressure for the lever can be supplied. Then, when pilot pressure is supplied through the pilot passage 8C, the plunger 80 moves forward and its tip blocks communication between the passages 8α and 86.

Further, when pilot pressure is supplied through the pilot passage 8d, communication between the passages 8α and 86 is enabled, and oil can freely pass therethrough.

, :31' In the embodiment shown in FIG. 71, a pressure regulating valve 9 is connected to the check valve 9. When the oil from the piston-side oil chamber B via the pressure regulating valve 91 and the passage 6 is prevented from flowing out to the passage 6 side by the check valve 9, 1ffl'4-+1-p71-'
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9 is configured to restrict the flow to the UCall. In this embodiment, a damping valve 10 is disposed in the poppet 90 facing the communication hole 9h with the check valve 9 and in the rod cover part IC of the hydraulic cylinder 1 shown in FIG. . This damping valve 10 has a poppet 102 which is biased from behind by a spring 100 and has an orifice 101 in the center.
The poppet 102 is configured so that it can be retracted by oil from the tank. Then, the rod side oil chamber A
It is formed so that a desired damping force can be obtained when the oil inside flows out into the passage 6.

An operable check valve 11 that enables the damping valve 10 to operate is located within the rod cover portion le and is connected to the damping valve 10. The operated check valve 11 also includes pilot passages IL], l
Z is connected and is formed to be in an open state when pilot pressure is supplied through the pilot passage 11α, and to function as a check valve when the pilot pressure is released. There is.

In the embodiment shown in FIG. 1, the operated check valve 11 is disposed behind the poppet 102 of the damping valve 10, and has a plunger 110 that slides when pilot pressure is supplied. and the plunger 1
When the plunger 110 slides and the steel ball 111 opens the through hole, the steel ball 111 passes through the orifice 101 of the poppet 102 that constitutes the damping valve 10 and flows into the back pressure side of the poppet 102. Oil flows through the through holes and passages 113 opened by the steel ball 111.
It is formed so as to flow out into the passage 6 through. Therefore, since the valve opening is controlled by the pilot flow, the operable check valve 11 connected thereto can be small.

Therefore, when pilot pressure is supplied to the operating check valve 11, the poppet 102 in the damping valve 10 can be moved back, that is, the damping valve 10 is activated and the pilot pressure is released. Then, the oil that has passed through the orifice 101 of the poppet 102 is trapped, and the poppet 102 is held in a closed state by the oil pressure and the force of the spring 100, and the damping valve lO
will not operate. In addition, since the back pressure chamber on the rear side of the poppet 102 in which the spring 100 is housed is formed to have a large diameter, it is possible to easily hold the poppet 102 in the closed position when the operating check valve 11 is closed.

Since the operated check valve 11 selectively enables the damping valve 10 to be activated or deactivated, instead of the embodiment shown in FIG. 1, a pilot passage 11α is provided as shown in FIG. A pilot switching valve 11 that puts the damping valve 10 into an operable state when pilot pressure is supplied from the pipe and puts the damping valve 10 into an inoperative state when the pie-foot pressure is released.
It is also possible to do so.

In the embodiment shown in FIG. 2, this pilot switching valve 11 has a poppet 111 energized from behind by a spring 110, and when supplied with pressure,
A passage 113 that moves backward and communicates with the rod side oil chamber A and a passage 114 that communicates with the damping valve 10 are formed to communicate with each other.

Therefore, when pilot pressure is supplied to the pilot switching valve 11, it moves to a communication position that allows the oil in the rod side oil chamber A to flow out to the passage 6 side, and the pilot pressure is released. is returned and moves to a blocking position that prevents the oil in the rod side oil chamber A from flowing out to the passage 6 side.

A pilot passage 11α connected to the operated check valve 11 shown in FIG. 1 is connected to a pilot solenoid valve 12. A pilot pump 13 is connected to the pilot solenoid valve 12. And again, F
The pilot solenoid valve 12 has a supply position 12α in which pilot pressure from the pilot pump is supplied to the operated check valve 11 via the pilot passage 11α, and a supply position 12α in which the pilot pressure is stopped being supplied to the pilot passage 11a. Discharge position 1 for discharging the oil in the pilot passage 11α into the reservoir tank 5
I have 25. Note that the pilot pump 13 is provided with a relief valve 13α.

In the embodiment shown in FIG. 2, the pilot solenoid valve 12 has a pilot pump 13 in the pilot switching valve 11.
A supply position 12α that supplies pilot pressure from the pilot pump 13 to the operated check valve 8 via the pilot passage 11α, and another supply position 12 that supplies pilot pressure from the pilot pump 13 to the operated check valve 8 via the pilot passage 8C.
C, and a discharge position 126 that allows the oil supplied to the pilot passages 8c and 11a to drain to the reservoir tank 5.

Here, the operation of the vehicle suspension system according to the present invention will be explained based on the embodiment shown in FIG.

First, in order to deactivate the suspension spring so that the vehicle can perform crane work etc. at the work site, pilot solenoid valve 1 must be activated.
2 is the discharge position 12A, and the pilot passage 11a
The operation of the damping valve 10 is prevented by an operating check valve 11 which is connected to the damping valve 10. In other words, the rod side oil chamber A
This prevents the oil inside from flowing out to the reservoir tank 5 side via the damping valve 10.

From this state, the main solenoid valve 3 is switched to the supply position 3α. As a result, pressure oil from the main pump 2 flows into the rod-side oil chamber A through the passage 4 and the check valve 7.

On the other hand, the oil in the piston side oil chamber B flows out into the passage 6 through the passage h, the passage 8α, the operating check valve 8 which is released by the supply of pressure oil from the passage 4, and the passage 8b,
It will flow out to the reservoir tank 5 side, and the hydraulic cylinder 1 will be compressed. As a result, when the hydraulic cylinder 1 reaches a desired compression state, that is, when the spring effect in the suspension system is reduced, the main electromagnetic valve 3 is switched to the discharge position 3h.

As a result, the supply of pressure oil to the rod-side oil chamber A is stopped, and the oil is sealed in the rod-side oil chamber A, resulting in a so-called oil lock state, and the extension of the hydraulic cylinder 1 by the suspension spring is prevented. The compression retention function is demonstrated.

Note that when the main solenoid valve 3 is switched and the pressure oil is no longer supplied through the passage 4, the operating check valve 8 will also prevent oil from flowing out from the piston side oil chamber B side. The inside of the piston side oil chamber B also exhibits a so-called oil lock state. Furthermore, when releasing the oil lock state in the rod side oil chamber A, the pilot solenoid valve 12 is switched to the supply position 12α.

Since the return force of the suspension spring is acting on cylinder 1,
The oil in the rod-side oil chamber A flows into the piston-side oil chamber B through the damping valve 10, the passage 6, the operating check valve 8 and the check valve 9, and the passage S, which are in the operating state, and the piston rod 1z leaves the piston rod 1z. The insufficient oil corresponding to the amount of water is supplied from the reservoir tank 5 and the return of the 28 circuit to the piston side oil chamber B via the passage 6, the operating check valves 8 and 9, and the passage S, and the hydraulic cylinder 1 is extended. It will be done.

Next, when the vehicle is running on the road, the pilot solenoid valve 12 is maintained at the supply position 12a.

When the hydraulic cylinder 1 is compressed in this state, the oil in the piston side oil chamber B is prevented from flowing from the passage 2 to the passage 6 by the check valve 9 and the operated check valve 8, so it passes through the check valve 1d. Flows into the rond side oil chamber A,
The oil in the volume of the piston rod 16 flows out into the reservoir tank 5 through the damping valve 10, the passage 6 and the back pressure valve 675 in the activated state.

Furthermore, when the hydraulic cylinder 1 is extended, the oil in the rond side oil chamber A is in an operating state when the damping valve 104 is in an operating state.
``J / 7 wife OK Niyama 1 Iji 7k 7 While flowing into the oil chamber B on the 7 side, the oil corresponding to the volume of the piston rod 1b sucks return oil from the power steering mechanism PS, and if this return oil is insufficient, is inhaled from the reservoir tank 5 through the suction valve 6α.

Therefore, the hydraulic cylinder 1 can expand and contract in response to the vibrations of the vehicle, and during the expansion and contraction, oil from the rod side oil chamber A passes through the damping valve 10. This will provide a buffering function that dampens road vibrations.

To activate the anti-nose dive function that prevents the nose dive phenomenon of the vehicle during brake operation in the above-mentioned state, the pilot solenoid valve 12 is switched to the discharge position 12A in conjunction with the brake operation, etc., and the damping valve 10 is placed in the inactive state. Make it.

As a result, the oil in the rod side oil chamber A is prevented from flowing out to the passage 6 side, and the oil in the piston side oil chamber B is prevented from flowing out to the outside by the check valve 9, which prevents nose dive during brake operation. The phenomenon is prevented.

In this state, if the piston is pushed up from the road surface due to riding on a bump or subjected to strong vibrations, the oil pressure in the piston side oil chamber B increases and the pressure regulating valve 9 is activated, causing the oil in the piston side oil chamber B to rise. is discharged into the reservoir tank 5, which can absorb shocks and strong vibrations caused by thrusting, thereby preventing deterioration of ride comfort and handling stability of the vehicle.

Additionally, in the suspension system according to the embodiment shown in Figure 2,
When using the compression holding function, use pilot solenoid valve 1.
2 to the discharge position 12A, and the main solenoid valve 3. is switched to the supply position 3α, and pressure oil from the main pump 2 is supplied into the rod-side oil chamber A to compress the hydraulic cylinder 1. At this time, the oil in the piston-side oil chamber B flows out into the reservoir tank 5 via the passage b, the passage 8a, the operated check valve 8, the passage 8h, and the passage 6.

When the hydraulic cylinder 1 reaches the desired maximum compression state by supplying oil into the rod-side oil chamber A, the main solenoid valve 3 is switched to the discharge position 36.

Furthermore, when the device is to exhibit a buffering function, the pilot solenoid valve 12 is switched to the supply position 12α. As a result, when the hydraulic cylinder 1 is compressed, the oil in the piston side oil chamber B is discharged from the reverse valve 1d.
The oil corresponding to the intrusion volume of the piston rod 1b flows into the rod side oil chamber A through the passage h and the passage 8.
α, open operated check valve 8, passage 875,
It flows out into the reservoir tank 5 through the passage 6. Also,
When the hydraulic cylinder 1 is extended, the oil in the oil chamber A on the O-rad side reaches the damping valve lO via the pilot switching valve 11 in the communication position, and flows through the damping valve 10 as well as through the passage 8α and the passage S. and flows into the piston side oil chamber B,
The shortage of oil corresponding to the withdrawal of the piston rod 1b is
The oil returns from the power steering mechanism PS and flows into the piston side oil chamber B from the reservoir tank 5 through the passage 6, passage 8b1, operating check valve 8, passage 8α, and passage.

Therefore, during the extension stroke of the hydraulic cylinder 1, oil passes through the damping valve 10, so that the desired damping function is achieved.

Then, when the buffering function described above is in a state where it can be performed,
When the anti-nose dive function for preventing the nose dive phenomenon of the vehicle is to be performed, the pilot solenoid valve 12 is switched to another supply position 12c.

As a result, the oil in the piston side oil chamber B is prevented from flowing out to the outside because the operating check valve 8 connected to the passage is closed, and the compression of the hydraulic cylinder 1 is prevented. That will happen. In this state, when it is pushed up from the road surface due to a bump or the like, the oil pressure in the piston-side oil chamber B increases, and the relief valve 13α of the pilot pump 13, which is balanced with the operating stroke valve 8, It will act as a pressure regulating valve, that is, the oil in the piston side oil chamber B will be discharged to the reservoir tank 5 side by opening the operating check valve 8.

Here, other changes to each of the above embodiments will be briefly explained.

The operated check valve 8 and check valve 9 in the embodiment shown in Figure 1 may be omitted when the hydraulic cylinders r are disposed on the left and right rear wheels of the vehicle, respectively. Furthermore, the operated check valve 11 shown in Figure 1 may be the pilot switching valve 11 shown in Figure 2, and the operated check valve 11 and pilot switching valve 11 may be electromagnetic switching valves. good. In particular, the operated check valve 11 shown in FIG.
When is used as an electromagnetic switching valve, the pilot passage 11α
, there is an advantage that the provision of the pilot solenoid valve 12 and the pilot pump 13 is omitted.

Further, in any of the embodiments described above, when the buffer function is in a state where the buffer function can be performed, that is, when the vehicle is running on the road, the pilot solenoid valve 1 is activated in conjunction with the brake operation.
2 is configured so that it can be switched to the discharge position 12h or another supply position 12C, so that when the brake is operated, the hydraulic cylinder on the front wheel side is locked to prevent the nose dive phenomenon, and the hydraulic cylinder on the rear wheel side is also locked. This makes it possible to prevent the phenomenon of the rear wheels from lifting up, thereby improving the handling stability of the vehicle.

Further, the hydraulic pressure setting of the pressure regulating valve 9 in Figure 1 can be made variable in proportion to the brake hydraulic pressure, so that the stronger the brake depression force, the greater the resistance to prevent nose dive. be. By disposing a throttle differentially in the pressure regulating valve 9 and allowing some nose dive when the anti-nose dive function is activated, the deterioration of the ride comfort and handling stability of the vehicle can be prevented. It is also possible to try to prevent this.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to make the suspension system of a vehicle exhibit a compression holding function and also to exhibit a buffering function that dampens road vibrations while the vehicle is running, thereby improving ride comfort during normal road running. In addition, it is possible to drive at high speed even in vehicles with short wheelbases and unstable running, such as latte lane vehicles.

In addition to exerting an anti-nose dive function that prevents the nose dive phenomenon while the vehicle is running, even if the anti-nose dive function is activated and the vehicle is pushed up by riding on a protrusion, etc., the pushing up action will not cause pressure. Since the amount of water is absorbed by the adjustment valve, even in special vehicles such as latte lane cars where the wheelbase is short and the nose dive phenomenon is likely to occur, the nose dive phenomenon is prevented and the ride comfort and driving stability of the vehicle are improved. This has the advantage that it improves performance, enables high-speed running, and eliminates deterioration in ride comfort and handling stability even when bumped up from the road surface.

[Brief explanation of drawings]

Figure 1 is a diagram showing one embodiment of a vehicle suspension system according to the present invention, and Figure 2 is a diagram showing another embodiment. 1... Hydraulic cylinder, 2... Main pump, 3...
・Main solenoid valve 1. 4, 6... Passage, 5... Reservoir tank, 7, 9... Check valve, 9... Pressure adjustment valve, 8, 11... Operate check valve, 8? , 11
α... Pilot passage, 10... Damping valve, 11...
・Pilot switching valve, 12...Pilot solenoid valve, 1
3-・Yu-pilot switching valve, A.・Red rod side oil chamber, B
...Piston side oil chamber, h...passage. Representative Patent Attorney Izumi Ohno

Claims (1)

[Claims] A suspension spring and a hydraulic cylinder are provided between the vehicle body frame and the wheels, and the hydraulic cylinder is compressed and the compressed state of the hydraulic cylinder is maintained to maintain the inoperative state of the suspension spring. In the suspension system for a vehicle, the suspension system includes a pressure regulating valve configured to operate during a pressure stroke of a hydraulic cylinder during a brake operation on the vehicle to control an anti-nose dive action on the wheels. and a damping valve formed to generate a damping force on the extension side at least during the extension stroke of the hydraulic cylinder, and to allow oil to be contained in the oil chamber on the rod side when the hydraulic cylinder is not in operation. A suspension system for a vehicle, which is characterized by: