WO2013047143A1

WO2013047143A1 - Suspension system

Info

Publication number: WO2013047143A1
Application number: PCT/JP2012/072745
Authority: WO
Inventors: 大下守人; 児島史雄; 境孝介; 大谷佳史
Original assignee: アイシン精機株式会社
Priority date: 2011-09-27
Filing date: 2012-09-06
Publication date: 2013-04-04

Abstract

The suspension system of the present invention has an upper cylinder chamber, a lower cylinder chamber, and a variable valve for adjusting the opening area of an opening part of the lower cylinder chamber. The suspension system is provided with: a first interconnecting path for interconnecting the upper cylinder chamber of one damping force control cylinder and the lower cylinder chamber of the other damping force control cylinder, incorporated into a pair of wheels of a vehicle; a second interconnecting path for interconnecting the lower cylinder chamber of one damping force control cylinder and the upper cylinder chamber of the other damping force control cylinder; and a pair of oil receptacles for retaining and discharging oil in response to the operation of the damping force control cylinders, the oil receptacles being provided respectively to the first connecting path and the second connecting path.

Description

Suspension system

The present invention relates to a suspension system that improves the ride comfort and handling stability of a vehicle.

Conventionally, vehicles are equipped with suspensions to improve ride comfort and handling stability. The suspension includes a spring that supports the vehicle weight and absorbs the shock, and a shock absorber that attenuates the vibration of the spring, and buffers the shock from the road surface. As a technique related to such a suspension, there are those described in Patent Document 1 and Patent Document 2, which are cited below.

The roll damping force control device for a vehicle described in Patent Document 1 includes a damping force generation mechanism and front and rear roll damping force control means. The damping force generation mechanism is installed between the front wheel and the vehicle body, and between the rear wheel and the vehicle body, and generates a damping force proportional to the roll angular velocity of the vehicle body. Specifically, on each of the front wheel side and the rear wheel side, the upper cylinder chamber of the left wheel side hydraulic cylinder is connected to the lower cylinder chamber of the right wheel side hydraulic cylinder via the hydraulic piping, and the lower side of the left wheel side hydraulic cylinder. The cylinder chamber is connected to the upper cylinder chamber of the right wheel side hydraulic cylinder via another hydraulic pipe. Thereby, each cylinder is cross-piped. Each hydraulic pipe is provided with a variable throttle valve. The front and rear roll damping force control means increases the damping force of the front and rear wheels as the vehicle speed increases, and controls the damping force generation mechanism so that the ratio of the damping force of the front wheels to the rear wheels increases as the steering angular velocity increases.

In the swing damping device for a vehicle described in Patent Document 2, a shock absorber is interposed between the left wheel and the vehicle body and between the right wheel and the vehicle body, and the left wheel and the vehicle body are separated from the shock absorber. The left hydraulic cylinder interposed between the left hydraulic cylinder, the right hydraulic cylinder interposed between the right wheel and the vehicle body, and the upper cylinder chamber of the left hydraulic cylinder and the lower cylinder chamber of the right hydraulic cylinder are connected in communication. A first oil passage, a second oil passage that connects the upper cylinder chamber of the right hydraulic cylinder and a lower cylinder chamber of the left hydraulic cylinder, and a third oil that connects the first oil passage and the reservoir tank. A damping mechanism including a road, a fourth oil path that connects the second oil path and the reservoir tank, and a variable throttle provided in each of the third oil path and the fourth oil path. With relative vertical movement It is provided with a control mechanism for controlling the degree of narrowing of the variable throttle.

Also, as a technique related to the hydraulic cylinder provided in the suspension system, there is a technique described in Patent Documents 3-5, which is cited below. The hydraulic cylinders described in

Patent Documents

3 and 4 are composed of a double cylinder type including a slidable piston and a piston rod, and the volume of the cylinder chamber divided into two chambers by the piston changes due to the movement of the piston. . The rigidity of an automobile suspension is controlled by generating an oil flow through a port provided in the hydraulic cylinder.

The fluid pressure damper of the suspension device described in Patent Document 5 is also composed of a double-cylinder type incorporating a slidable piston and a piston rod. This fluid pressure damper also changes the volume of the oil chamber (corresponding to the “cylinder chamber”) partitioned by the piston in the cylinder due to the movement of the piston, and suppresses a change in the attitude of the automobile by generating an oil flow. .

Japanese Patent Laid-Open No. 4-46815 JP-A-5-193331 JP 2005-133902 A JP 2007-205416 A Japanese Patent No. 4740086

The vehicle roll damping force control device of Patent Document 1 is not provided with a device for adding roll rigidity in addition to a spring. For this reason, for example, in a situation where the vehicle turns for a long time such as a rampway, it is inevitable that the roll amount of the vehicle becomes large and the turning performance deteriorates. In addition, although the ride comfort can be ensured when the in-phase bounce is input, the unsprung flapping due to the input of each wheel is in accordance with the initially set damping force of the shock absorber. For this reason, it is not always possible to ensure optimal grounding and riding comfort.

Also, the damping force in the roll direction of the front and rear wheels during turning can be controlled by a variable throttle valve provided in the hydraulic piping. However, when there is an input for moving the vehicle body in the roll direction by a relatively large single wheel input, the vehicle body is shaken as it is, and deterioration of ride comfort and running stability is inevitable.

Also, understeer and oversteer are improved by controlling the front and rear damping force valves using vehicle speed sensors and steering angle sensors to change the absolute value and ratio of front and rear roll damping. However, the neutral steer turning state cannot be secured.

Further, according to the vehicle suspension device described in Patent Document 2, since both the shock absorber and the damping mechanism are arranged in parallel, there is a problem that the structure around the wheel is complicated. Furthermore, it is necessary to detect the relative vertical movement (amount, speed, etc.) between the wheel and the vehicle body, and to control the damping mechanism that accompanies it.

In the hydraulic cylinders described in

Patent Documents

3 and 4, the cylinder outer cylinder and the port are integrally formed. On the other hand, the fluid pressure damper described in Patent Document 5 has a hollow rod interior and uses the rod interior as an oil passage. For this reason, since it is necessary to connect piping to the outer cylinder of a cylinder, when mounting in a vehicle is considered, it is necessary to arrange | position any one of piping, a rod, and a dust seal part below a vehicle. For this reason, piping or a rod and a dust seal part may deteriorate or be damaged by stepping stones, dust, muddy water, or the like.

In view of the above problems, an object of the present invention is to provide a suspension system capable of realizing optimum riding comfort and running stability regardless of the running state of a vehicle.

The characteristic configuration of the suspension system according to the present invention for achieving the above object is as follows:
The upper cylinder chamber that increases in volume when expanded and decreases in volume when contracted, the lower cylinder chamber that decreases in volume when expanded and increases in volume when contracted, and the flow rate of oil flowing out of the lower cylinder chamber A variable valve that adjusts based on a detection result of a detection unit that detects a physical quantity of the vehicle, and a damping force control cylinder incorporated in a pair of wheels among a plurality of wheels of the vehicle,
A first communication passage communicating the upper cylinder chamber of one damping force control cylinder and the lower cylinder chamber of the other damping force control cylinder;
A second communication passage communicating the lower cylinder chamber of the one damping force control cylinder and the upper cylinder chamber of the other damping force control cylinder;
A pair of oil receivers that are provided in each of the first communication path and the second communication path, and store and discharge oil in the first communication path and the second communication path according to the operation of the damping force control cylinder. And
It is in the point equipped with.

With such a characteristic configuration, the damping force in the extension direction of the suspension can be optimized, so that the ground contact with the road surface can be improved. For this reason, between the pair of wheels assembled with the pair of damping force control cylinders, the damping force can be controlled to suppress the movement of the vehicle body. Therefore, it is possible to realize optimum riding comfort and running stability regardless of the running state of the vehicle.

Further, it is preferable that an acceleration detection unit that detects vertical acceleration of the vehicle body of the vehicle is provided, and the variable valve adjusts the flow rate of the oil based on a detection result of the acceleration detection unit.

With such a configuration, the damping force of the suspension can be adjusted according to the running state of the vehicle, so that the ride comfort can be improved. Therefore, it is possible to realize optimum traveling stability.

Further, it is preferable that the oil receiving portion is an accumulator.

With such a configuration, it is possible to appropriately maintain the oil flow rate in the first communication path and the second communication path.

Further, it is preferable that a variable valve for limiting the flow rate of the oil flowing into the accumulator is provided.

With such a configuration, the accumulator can appropriately store and discharge the oil in the first communication path and the second communication path.

Further, it is preferable that a check valve is provided in parallel with the variable valve for limiting the flow rate of the oil flowing into the accumulator.

With such a configuration, it is possible to prevent oil from flowing into the accumulator by the check valve and to smoothly flow out of the accumulator by the variable valve. Therefore, it is possible to appropriately adjust the pressures of the first communication path and the second communication path.

Further, it is preferable that the pair of wheels are a left wheel and a right wheel provided to face each other in the width direction of the vehicle.

With such a configuration, different loads on the left and right sides of the vehicle can be appropriately attenuated. Therefore, it is possible to realize optimum riding comfort and running stability.

Alternatively, the pair of wheels may be a front wheel and a rear wheel provided in the front-rear direction of the vehicle.

With such a configuration, different loads before and after the vehicle can be appropriately attenuated. Therefore, it is possible to realize optimum riding comfort and running stability.

Further, the left hydraulic cylinder interposed between the left wheel and the vehicle body and the right hydraulic cylinder interposed between the right wheel and the vehicle body are respectively connected to the upper cylinder chamber and the lower cylinder chamber. It is preferable that the port for supplying and discharging the oil is disposed at a position separated from the lower fixing portion.

With such a configuration, it is possible to make it difficult to be affected by jumping stones and muddy water splashes as the vehicle travels. Therefore, durability and reliability can be improved.

Further, it is preferable that the port for supplying and discharging oil in the upper cylinder chamber and the port for supplying and discharging oil in the lower cylinder chamber are disposed on the side of the fixed portion of the rod provided on the upper side. It is.

With such a configuration, it is possible to eliminate the influence of jumping stones and muddy water splashes associated with the traveling of the vehicle. Therefore, durability and reliability can be improved.

An upper cylinder chamber oil passage for supplying and discharging oil in the upper cylinder chamber and a lower cylinder chamber oil passage for supplying and discharging oil in the lower cylinder chamber are provided on the radially inner side of the rod. It is preferable that

With such a configuration, the upper cylinder chamber oil passage and the lower cylinder chamber oil passage can be protected by the rod. Therefore, it is not necessary to take measures to increase the durability of the upper cylinder chamber oil passage and the lower cylinder chamber oil passage, and thus an increase in cost can be avoided.

In addition, a cylindrical member is coaxially arranged on the radially inner side of the rod, the lower cylinder chamber oil passage is formed on the radially inner side of the tubular member, and the inner peripheral surface of the rod and the cylinder It is preferable that the upper cylinder chamber oil passage is formed between the outer peripheral surface of the cylindrical member.

With such a configuration, it is possible to configure the upper cylinder chamber oil passage and the lower cylinder chamber oil passage simply by arranging cylinders of different diameters on the same axis. Therefore, it can be configured with a simple structure.

It is the figure which showed typically the vehicle carrying the suspension system which concerns on 1st Embodiment. It is the figure shown about addition of roll rigidity by an accumulator. It is the figure which showed the example when the Fr single wheel of the vehicle carrying the suspension system which concerns on 1st Embodiment goes up the level | step difference. It is the figure which showed the example when the Fr single wheel of the vehicle carrying the suspension system which concerns on 1st Embodiment goes up the level | step difference. It is the figure which showed the example when the vehicle carrying the suspension system which concerns on 1st Embodiment turns left. It is the figure which showed the example when the vehicle carrying the suspension system which concerns on 1st Embodiment turns left. It is a flowchart which shows the control in case there exists single-wheel input with respect to the vehicle carrying the suspension system which concerns on 1st Embodiment. It is a flowchart which shows control when the vehicle carrying the suspension system which concerns on 1st Embodiment is turning. It is the figure which showed the test running pattern typically. It is the figure which showed the difference in the running characteristics by the presence or absence of a suspension system. It is the figure which showed the difference in the running characteristics by the presence or absence of a suspension system. It is the figure which showed the difference in the running characteristics by the presence or absence of a suspension system. It is the figure which showed typically the vehicle carrying the suspension system which concerns on 2nd Embodiment. It is the figure which showed typically the vehicle carrying the suspension system which concerns on 3rd Embodiment. It is the figure which showed the example at the time of braking of the vehicle carrying the suspension system which concerns on 3rd Embodiment. It is the figure which showed the example at the time of braking of the vehicle carrying the suspension system which concerns on 3rd Embodiment. It is the figure which showed the example at the time of start and acceleration of the vehicle carrying the suspension system which concerns on 3rd Embodiment. It is the figure which showed the example at the time of start and acceleration of the vehicle carrying the suspension system which concerns on 3rd Embodiment. It is the figure which showed the example when the vehicle carrying the suspension system which concerns on 3rd Embodiment turns right. It is the figure which showed the example when the vehicle carrying the suspension system which concerns on 3rd Embodiment turns right. It is the figure which showed typically the vehicle carrying the suspension system which concerns on 4th Embodiment. It is explanatory drawing which shows the relationship between the pressure of a damping force valve | bulb, and flow volume. It is explanatory drawing which shows the relationship between piston speed and damping force. It is a schematic diagram which shows the effect | action of the suspension system which concerns on 4th Embodiment. It is a schematic diagram which shows the effect | action of the suspension system which concerns on 4th Embodiment. It is a schematic diagram which shows the effect | action of the suspension system which concerns on 4th Embodiment. It is a schematic diagram which shows the suspension system which concerns on 5th Embodiment. It is a schematic diagram which shows the effect | action of the suspension system which concerns on 5th Embodiment. It is a schematic diagram which shows the effect | action of the suspension system which concerns on 5th Embodiment. It is a schematic diagram which shows the effect | action of the suspension system which concerns on 5th Embodiment. It is a schematic diagram which shows the effect | action of the suspension system which concerns on 5th Embodiment. It is a schematic diagram which shows the effect | action of the suspension system which concerns on 5th Embodiment. It is a schematic diagram which shows the suspension system which concerns on 6th Embodiment. It is a schematic diagram which shows a hydraulic cylinder. It is a schematic diagram which shows the effect | action of the suspension system of another embodiment. It is a schematic diagram which shows the hydraulic cylinder of another embodiment.

1. Suspension system Hereinafter, embodiments of the present invention will be described in detail. The suspension system 100 according to the present invention is mounted on a vehicle and has a function of realizing optimal riding comfort and running stability for a vehicle occupant.

1-1. First Embodiment A first embodiment of the suspension system 100 will be described. FIG. 1 schematically shows a suspension system 100 according to this embodiment mounted on a vehicle 1. The suspension system 100 includes a damping force control cylinder 10, a first communication path 21, a second communication path 22, and an oil receiving portion 23.

The damping force control cylinder 10 is incorporated into a pair of wheels 2 among a plurality of wheels 2 of the vehicle 1. The plurality of wheels 2 are the left front wheel 2A, the right front wheel 2B, the left rear wheel 2C, and the right rear wheel 2D of the vehicle 1. The pair of wheels 2 are a left wheel and a right wheel provided to face each other in the width direction of the vehicle 1. In the present embodiment, the damping force control cylinder 10 is composed of a pair and is incorporated in the left rear wheel 2C and the right rear wheel 2D. In the present embodiment, when it is particularly necessary to distinguish in the following description, the damping force control cylinder 10 incorporated in the left rear wheel 2C is denoted by reference numeral 10A, and the damping force control cylinder 10 incorporated in the right rear wheel 2D. Is shown with reference numeral 10B.

The damping force control cylinder 10 has an upper cylinder chamber 10U, a lower cylinder chamber 10L, and a variable valve 11, and is composed of an extendable cylinder damper. The upper cylinder chamber 10U is configured to increase in volume when the cylinder damper extends and to decrease in volume when the cylinder damper contracts. The lower cylinder chamber 10L is configured to have a smaller volume when extended and a larger volume when contracted.

The variable valve 11 adjusts the flow rate of the oil R flowing out from the lower cylinder chamber 10L based on the detection result of the detection unit that detects the physical quantity of the vehicle. As described above, the damping force control cylinder 10 includes a pair. Therefore, the variable valve 11 also includes a pair of

variable valves

11A and 11B. The pair of

variable valves

11A and 11B are configured such that the flow rate of the oil R flowing out from the lower cylinder chamber 10L can be independently adjusted. That is, the variable valve 11A and the variable valve 11B can be adjusted to have different oil R flow rates.

Each lower cylinder chamber 10L is provided with an opening (not shown), and a variable valve 11 is provided in communication with the opening. The variable valve 11 is configured such that the opening area can be changed by electrical control. Specifically, the opening area is changed by a signal from a control unit (not shown). Thereby, the variable valve 11 can restrict | limit the flow volume of the oil R which flows out out of each lower cylinder chamber 10L. The variable valve 11 can circulate oil R also in the inflow direction.

Also, a check valve 12 is provided in parallel with the variable valve 11. As described above, the variable valve 11 includes a pair of

variable valves

11A and 11B. For this reason, the check valve 12 also includes a check valve 12A provided in parallel to the variable valve 11A and a check valve 12B provided in parallel to the variable valve 11B. The check valve 12 operates so that the oil R does not flow out from the lower cylinder chamber 10L, and the oil R flows smoothly into the lower cylinder chamber 10L.

Each upper cylinder chamber 10U is provided with an opening (not shown), a damping force valve 14 (14A, 14B) that generates a damping force when oil R flows out (when contracted), and an inflow A check valve 17 (17A, 17B) for smoothly flowing the oil R at the time (extension) is provided in communication. The check valve 17A is opened against the urging force of the spring, and the oil R flows only in directions different from the damping force valve 14A. Similarly, the check valve 17B is opened against the urging force of the spring, and the oil R flows only in directions different from the damping force valve 14B. Therefore, the path through which oil R flows out from each upper cylinder chamber 10U is different from the path through which oil R flows into 10U into each upper cylinder chamber.

The first communication path 21 communicates the upper cylinder chamber 10U of one damping force control cylinder 10A and the lower cylinder chamber 10L of the other damping force control cylinder 10B. That is, the upper cylinder chamber 10U of the damping force control cylinder 10A communicates with the first communication passage 21 via the check valve 17A and the damping force valve 14A, and the lower cylinder chamber 10L of the damping force control cylinder 10B includes the variable valve 11B, And it communicates with the first communication path 21 via the check valve 12B.

The second communication path 22 communicates the lower cylinder chamber 10L of one damping force control cylinder 10A and the upper cylinder chamber 10U of the other damping force control cylinder 10B. That is, the lower cylinder chamber 10L of the damping force control cylinder 10A communicates with the second communication path 22 via the variable valve 11A and the check valve 12A, and the upper cylinder chamber 10U of the damping force control cylinder 10B includes the check valve 17B and The second communication passage 22 communicates with the damping force valve 14B.

The oil receiving portion 23 is provided in each of the first communication path 21 and the second communication path 22, and stores oil R in the first communication path 21 and the second communication path 22 according to the operation of the damping force control cylinder 10. And discharge. Therefore, the oil receiving portion 23 includes a pair of an oil receiving portion 23 A communicating with the first communication passage 21 and an oil receiving portion 23 B communicating with the second communication passage 22. In this embodiment, the oil receiving part 23 is comprised from an accumulator. The roll rigidity of the vehicle can be imparted by the accumulator. The accumulator container is filled with gas, and acts as a gas spring by changing the volume of the gas due to the volume change of the oil R in the accumulator container. That is, when the oil R flows into the accumulator, the gas is compressed, a repulsive force due to the spring force of the gas is added to the oil R, and the roll rigidity (stabilizer function) of the vehicle can be imparted. In the following description, the oil receiver 23 (23A, 23B) will be described as an accumulator 23 (23A, 23B).

The suspension system 100 includes a variable valve 24 that restricts the flow rate of the oil R flowing into the accumulator 23. As described above, the accumulator 23 includes a pair of

accumulators

23A and 23B. Therefore, the variable valve 24 also includes a pair of

variable valves

24A and 24B. Similar to the variable valve 11, the variable valve 24 is configured such that the opening area can be changed by electrical control. Specifically, the opening area is changed by a signal from a control unit (not shown). Thereby, the variable valve 24 can limit the flow rate of the oil R flowing into the accumulator 23. The variable valve 24 can circulate the oil R also in the outflow direction.

Further, a check valve 25 is provided in parallel with the variable valve 24. As described above, the variable valve 24 includes a pair of

variable valves

24A and 24B. For this reason, the check valve 25 also includes a check valve 25A provided in parallel with the variable valve 24A and a check valve 25B provided in parallel with the variable valve 24B. The check valve 25 operates so that the oil R flows smoothly from the accumulator 23 while preventing the oil R from flowing into the accumulator 23. Therefore, the oil R flows out from the accumulator 23 through the check valve 25. On the other hand, the oil R flows into the accumulator 23 only through the variable valve 24. Thereby, it becomes possible to adjust each pressure of the 1st communicating path 21 and the 2nd communicating path 22.

The effect of such an accumulator 23 is shown in FIG. In FIG. 2, the vertical axis represents the spring reaction force, and the horizontal axis represents the stroke amount. In FIG. 2, the broken line indicates the characteristic due to the spring 40 alone, and the solid line indicates the characteristic due to both the spring 40 and the accumulator 23. As shown in FIG. 2, by using the accumulator 23, the same effect as that of the stabilizer can be obtained when the vehicle is rolled.

Although not shown, an orifice level communication path that is arranged in parallel to the variable valve 24 and the check valve 25 is provided in the variable valve 24. The communication path allows the accumulator 23 to communicate with each of the first communication path 21 and the second communication path 22 at all times, and can also provide a damping force characteristic during a low-speed cylinder stroke.

Returning to FIG. 1, the vehicle 1 is provided with an acceleration detection unit 30 that detects the acceleration in the vertical direction of the vehicle body of the vehicle 1. The detection result of the acceleration detection unit 30 is transmitted to a control unit (not shown). The control unit adjusts the flow rate of the oil R flowing out from the lower cylinder chamber 10L based on the detection result of the acceleration detection unit 30. Therefore, in the present embodiment, the “detection unit” described above corresponds to the “acceleration detection unit 30”.

The communication mechanism 39 makes the first communication path 21 and the second communication path 22 in communication and non-communication. The communication mechanism 39 can be configured by a mechanical type or an electromagnetic type, and does not affect suspension performance based on the traveling of the vehicle 1 described later. The communication mechanism 39 is a vehicle 1 that is caused by internal leakage of the oil R in the hydraulic circuit including the first communication path 21 and the hydraulic circuit including the second communication path 22, or by an increase or decrease in the volume of the oil R due to a temperature change of the oil R. For example, the oil R is leaked between the two hydraulic circuits at a very small flow rate to maintain the volume balance and prevent an unbalanced state.

On the other hand, shock absorbers 49 are incorporated in the left front wheel 2A and the right front wheel 2B of the vehicle 1, respectively. This shock absorber 49 is composed of a pair, and the upper cylinder chamber 49U and the lower cylinder chamber 49L of each shock absorber 49 communicate with each other via a variable valve 350 and a check valve 351. Such a shock absorber 49 is well known and will not be described. A known stabilizer 352 is provided between the pair of shock absorbers 49 incorporated in the left front wheel 2A and the right front wheel 2B of the vehicle 1. In the present embodiment, the suspension system 100 having such a configuration is provided in the vehicle 1.

Next, the operation of the suspension system 100 will be described. For example, as shown in FIG. 3, when the left front wheel 2 A of the vehicle 1 travels on a step (after climbing up), the direction of movement of the vehicle body is as indicated by the arrow in FIG. 3, and there is relative movement between the wheel and the vehicle body. Arise. The damping force control cylinder 10A of the left rear wheel 2C extends in the rebound direction, and the damping force control cylinder 10B of the right rear wheel 2D contracts in the bound direction. In this case, as shown in FIG. 4, the oil R flows out from the lower cylinder chamber 10L of one damping force control cylinder 10A via the variable valve 11A, and the upper cylinder chamber of the other damping force control cylinder 10B. 10U also flows out through the damping force valve 14B, and the oil R flows into the accumulator 23B through the variable valve 24B to generate a large damping force in the left and right damping

force control cylinders

10A and 10B. At this time, check valves (check valve 25A, check valve 17A, check valve) are connected from the accumulator 23A to the upper cylinder chamber 10U of one damping force control cylinder 10A and the lower cylinder chamber 10L of the other damping force control cylinder 10B. Oil R flows smoothly through the valve 12B).

Further, for example, as shown in FIG. 5, when the vehicle 1 is traveling while turning left, an upward load is applied to the left side of the vehicle 1 and a downward load is applied to the right side of the vehicle 1. In this case, as shown in FIG. 6, the oil R flows out from the lower cylinder chamber 10L of one damping force control cylinder 10A via the variable valve 11A, and the upper cylinder chamber of the other damping force control cylinder 10B. Also from 10U, it flows out through the damping force valve 14B. These oils R flow into the accumulator 23B through the variable valve 24B.

The oil R smoothly flows into the upper cylinder chamber 10U of one damping force control cylinder 10A via the check valve 17A, and the check valve 12B also enters the lower cylinder chamber 10L of the other damping force control cylinder 10B. Flows smoothly through. These oils R correspond to those that have flowed out of the accumulator 23A through the check valve 25A.

At this time, a large damping force is applied to the damping force control cylinder 10A by the variable valve 11A of the lower cylinder chamber 10L of the damping force control cylinder 10A and the variable valve 24B of the accumulator 23B. On the other hand, a large damping force acts on the damping force control cylinder 10B by the damping force valve 14B and the variable valve 24B of the accumulator 23B.

Thus, the suspension system 100 functions as a suspension with damping force control. For normal straight running and gentle curves, the acceleration detection unit 30 provided in the vehicle 1 estimates the movement of the vehicle body due to unsprung input (flapping) from the road surface, and optimally controls the damping force in the extension direction of each wheel. By doing so, the fluttering of the wheel 2 is suppressed, the grounding property is improved, and the riding comfort and the running stability are ensured.

FIG. 7 shows a flow of processing performed in the control unit when a rolling direction component force is input to the vehicle 1 by a single wheel input of the front wheel. For example, when a rolling direction component force is input to the vehicle 1 by a single wheel input of the front wheels (step # 01), the vehicle body side motion due to the input from the road surface is estimated based on the detection result of the acceleration detection unit 30 (step # 02). ), The movement of the vehicle body is suppressed by controlling the damping force of the variable valve 11 on the rear wheel side (step # 03). Thereby, riding comfort can be improved. Specifically, when an input in the bounce direction is input to the right front wheel 2B, a vertical upward load is applied to the front right side of the vehicle body due to the reaction force, and the upper vehicle body moves in an upward direction. Move in the direction. The movement of the vehicle body is estimated based on the detection result of the acceleration detection unit 30 mounted on the vehicle 1, and the variable valve 11 on the rear wheel side is controlled to increase the roll damping force, thereby suppressing the movement of the vehicle body.

FIG. 8 shows a flow of processing performed by the control unit when a rolling direction component force is input when the vehicle 1 is turning. At the time of turning where the lateral acceleration occurs to some extent, the movement of the vehicle body is estimated (step # 03) based on the detection result of the steering angle sensor (step # 01) and the detection result of the vehicle speed sensor (step # 02). By controlling the damping force of the variable valve 11 and the variable valve 24 on the rear wheel side so that the neutral steering is synchronized (step # 04) and changing the roll stiffness distribution, the vehicle stability during turning and turning can be improved. improves. Further, according to this configuration, in addition to the roll rigidity by the spring 40, it is possible to add the roll rigidity based on the supply pressure from the accumulator 23 only at the time of the roll, and it is constant even when the turning is continued for a relatively long time. The following rolls can be suppressed. Therefore, vehicle stability can be improved.

Next, the effect will be described using data obtained when the vehicle 1 having the suspension system 100 travels. A traveling pattern of the vehicle 1 is shown in FIG. A pair of pylons having a spacing of 2.25 m is arranged in three rows every 20 m. The pair of pylons in the fourth row has a distance of 2.8 m centering on the left end of the pylon on the left side in the third row in the traveling direction, and is 20 m away from the third row pylon in the traveling direction. Be placed. A pair of pylons in the 5th to 7th rows are concentric with the pylons in the 1st to 3rd rows and are arranged every 20 m at intervals of 2.8 m.

The relationship between the steering angle and the yaw rate of the steering when the vehicle 1 travels in such a traveling pattern, the relationship between the steering angle and the roll angle, and the relationship between the steering angle and the lateral acceleration are shown in FIG. 12. For comparison, the characteristic when the suspension system 100 is not mounted is indicated by a broken line, and the characteristic when the suspension system 100 is mounted is indicated by a solid line. As shown in FIG. 10, the yaw with respect to the steering angle is stable by the suspension system 100. Further, as shown in FIG. 11, the suspension system 100 also stabilizes the roll posture with respect to the steering angle. Furthermore, as shown in FIG. 12, the suspension system 100 accelerates the rise of the lateral acceleration with respect to the steering angle. By providing the suspension system 100 in this manner, traveling stability and agility are improved.

As described above, according to the present suspension system 100, during normal traveling in a state where the lateral acceleration such as straight traveling or a gentle curve is small, the state of the vehicle body is detected based on the detection result of the acceleration detection unit 30 disposed on the vehicle body, and damping force control is performed. Riding comfort can be improved by controlling the damping force on the extension side of each wheel of the cylinder 10. In addition, when a rolling direction component force is input to the vehicle 1 by a single wheel input on the front wheel side, the rear wheel side variable valve 11 and the variable valve 24 function as a damping force variable valve, and control the damping force to control the vehicle body. Suppresses movement. Further, when turning such that lateral acceleration occurs, the damping force of the variable valve 11 on the rear wheel side and the variable valve 24 is controlled by the steering angle sensor and the vehicle speed sensor so that the neutral steering in which the yaw and the lateral acceleration are synchronized, By changing the roll rigidity distribution before and after the vehicle 1, an ideal turning state of the vehicle 1 can always be ensured.

1-2. Second Embodiment Next, a second embodiment of the suspension system 100 will be described. In the first embodiment, it has been described that the suspension system 100 is provided on the rear wheel side and the stabilizer 352 is provided on the front wheel side. This embodiment is different from the first embodiment in that a suspension system 100 is also provided on the front wheel side.

FIG. 13 schematically shows the vehicle 1 provided with the suspension system 100 according to the present embodiment. As shown in FIG. 13, the suspension system 100 on the rear wheel side is the same as that of the first embodiment. The suspension system 100 on the front wheel side is the same as the suspension system 100 on the rear wheel side. Accordingly, the operation and function are the same as those in the first embodiment, and will be described briefly below.

In the suspension system 100 of the present embodiment, the damping force control cylinders 10 on the front wheel side and the rear wheel side are configured by cross-connecting the upper cylinder chamber 10U and the lower cylinder chamber 10L on the left and right, respectively. By providing the suspension system 100 on both the front wheel side and the rear wheel side as described above, the effect can be further enhanced as compared with the suspension system 100 of the first embodiment. For example, when an input in the bounce direction is input to the right front wheel 2B, a vertical upward load is applied to the front right side of the vehicle body by the reaction force, and the vehicle body moves in the upward direction, and the entire vehicle body relatively moves in the rolling direction. . The movement of the vehicle body is estimated from the detection result of the acceleration detection unit 30 mounted on the vehicle 1, and the variable valves 11 and the variable valves 24 on both the front wheel side and the rear wheel side are controlled to increase the roll damping force, Furthermore, the movement of the vehicle body is suppressed.

The variable valve 11 on both the front wheel side and the rear wheel side so that the neutral steering in which the yaw and the lateral G are synchronized by the detection result of the steering angle sensor and the detection result of the vehicle speed sensor at the time of turning where the lateral acceleration occurs to some extent, and By controlling the damping force of the variable valve 24 and changing the roll stiffness distribution, agility and vehicle stability during turning are improved. Further, according to this configuration, in addition to the roll rigidity by the spring, the roll rigidity based on the supply pressure from the accumulator 23 can be added only at the time of the roll, and even when turning for a relatively long time, the front wheel side And the roll can be suppressed on both the rear wheel side. Therefore, vehicle stability can be further improved.

1-3. Third Embodiment Next, a third embodiment of the suspension system 100 will be described. In the first and second embodiments, it has been described that the suspension system 100 is provided across the left wheel and the right wheel provided to face each other in the width direction of the vehicle 1. In the present embodiment, the suspension system 100 is different from the first and second embodiments in that the suspension system 100 is provided over front and rear wheels provided in the front-rear direction of the vehicle 1. Below, it demonstrates focusing on a different point.

FIG. 14 schematically shows the suspension system 100 according to this embodiment mounted on the vehicle 1. A damping force control cylinder 10 included in the suspension system 100 according to the present embodiment is incorporated into a pair of wheels 2 among a plurality of wheels 2 included in the vehicle 1. The plurality of wheels 2 are the left front wheel 2A, the right front wheel 2B, the left rear wheel 2C, and the right rear wheel 2D of the vehicle 1. The pair of wheels 2 are a front wheel and a rear wheel provided in the front-rear direction of the vehicle 1. Therefore, the damping force control cylinder 10 consists of a pair. In the present embodiment, the left front wheel 2A and the left rear wheel 2C are paired, and the right front wheel 2B and the right rear wheel 2D are paired.

In the following description, when it is particularly necessary to distinguish, the damping force control cylinder 10 incorporated in the left front wheel 2A and the right front wheel 2B is indicated by reference numeral 10A, and the damping force incorporated in the left rear wheel 2C and the right rear wheel 2D. The force control cylinder 10 is indicated by reference numeral 10B. Since the suspension system 100 provided on the left side of the vehicle 1 and the suspension system 100 provided on the right side of the vehicle 1 are similar in operation and function, the suspension system 100 provided mainly on the left side of the vehicle 1 will be used below. I will explain.

The first communication path 21 according to the present embodiment communicates the upper cylinder chamber 10U of one damping force control cylinder 10A and the lower cylinder chamber 10L of the other damping force control cylinder 10B. That is, the upper cylinder chamber 10U of the damping force control cylinder 10A incorporated in the left front wheel 2A communicates with the first communication passage 21 via the damping force valve 14A and the check valve 17A, and the damping incorporated in the left rear wheel 2C. The lower cylinder chamber 10L of the force control cylinder 10B communicates with the first communication passage 21 via the variable valve 11B and the check valve 12B.

Further, the second communication path 22 according to the present embodiment communicates the lower cylinder chamber 10L of one damping force control cylinder 10A and the upper cylinder chamber 10U of the other damping force control cylinder 10B. That is, the lower cylinder chamber 10L of the damping force control cylinder 10A incorporated in the left front wheel 2A communicates with the second communication passage 22 via the variable valve 11A and the check valve 12A, and the damping incorporated in the left rear wheel 2C. The upper cylinder chamber 10U of the force control cylinder 10B communicates with the second communication path 22 via the damping force valve 14B and the check valve 17B.

In the present embodiment, the suspension system 100 having such a configuration is provided on the left side of the vehicle 1. On the other hand, the right front wheel 2B and the right rear wheel 2D of the vehicle 1 are also provided with a suspension system 100 configured in the same manner as described above. In the suspension system 100 according to the present embodiment, the stabilizer 352 is provided on the front side of the vehicle 1 and the rear side of the vehicle 1 along the width direction (between the left side portion and the right side portion of the vehicle 1).

Next, the operation of the suspension system 100 according to this embodiment will be described. For example, as shown in FIG. 15, when the vehicle 1 brakes, the front wheel side damping force control cylinder 10A relatively strokes in the bound direction as the front of the vehicle body squeezes. At the same time, as the rear of the vehicle body is lifted, the damping force control cylinder 10B on the rear wheel side relatively strokes in the rebound direction. In this case, as shown in FIG. 16, the oil R flows out from the upper cylinder chamber 10U of one damping force control cylinder 10A via the damping force valve 14A, and the lower cylinder of the other damping force control cylinder 10B. It also flows out from the chamber 10L through the variable valve 11B. These oils R flow into the accumulator 23A through the variable valve 24A.

The oil R smoothly flows into the lower cylinder chamber 10L of one damping force control cylinder 10A via the check valve 12A, and the check valve 17B enters the upper cylinder chamber 10U of the other damping force control cylinder 10B. Flows smoothly through. These oils R correspond to those that have flowed out of the accumulator 23B via the check valve 25B.

At this time, a large damping force acts on the damping force control cylinder 10A by the damping force valve 14A of the upper cylinder chamber 10U of the damping force control cylinder 10A and the variable valve 24A of the accumulator 23A. On the other hand, a large damping force is applied to the damping force control cylinder 10B by the variable valve 11B of the lower cylinder chamber 10L of the damping force control cylinder 10B and the variable valve 24A of the accumulator 23A.

Further, for example, as shown in FIG. 17, when the vehicle 1 starts and accelerates, the front wheel side damping force control cylinder 10A relatively strokes in the rebound direction as the front of the vehicle 1 is lifted. At the same time, the rear of the vehicle squeezes, and accordingly, the damping force control cylinder 10B on the rear wheel side relatively strokes in the bound direction. In this case, as shown in FIG. 18, the oil R flows out from the lower cylinder chamber 10L of one damping force control cylinder 10A via the variable valve 11A, and the upper cylinder chamber of the other damping force control cylinder 10B. Also from 10U, it flows out through the damping force valve 14B. These oils R flow into the accumulator 23B through the variable valve 24B.

Further, for example, as shown in FIG. 19, when the vehicle 1 is traveling while turning right, an upward load is applied to the right side of the vehicle 1 and a downward load is applied to the left side of the vehicle 1. In this case, as shown in FIG. 20, the oil R flows out from the upper cylinder chamber 10U of the damping force control cylinder 10B incorporated in the left rear wheel 2C via the damping force valve 14B. The oil R smoothly flows into the lower cylinder chamber 10L of the damping force control cylinder 10A incorporated in the left front wheel 2A via the check valve 12A, and a small amount of oil R corresponding to the rod entering the damping force control cylinder 10A. Flows into the accumulator 23B through the variable valve 24B.

Also, the oil R flows out from the upper cylinder chamber 10U of the damping force control cylinder 10A incorporated in the left front wheel 2A through the damping force valve 14A. This oil R flows smoothly into the lower cylinder chamber 10L of the damping force control cylinder 10B incorporated in the left rear wheel 2C via the check valve 12B, and a small amount of oil corresponding to the rod entering the damping force control cylinder 10B. R flows into the accumulator 23A through the variable valve 24A.

At this time, a damping force is applied to the damping force control cylinder 10B by the damping force valve 14B, but the oil R flowing into the variable valve 24B of the accumulator 23B is a small amount corresponding to the amount of the rod entering the damping force control cylinder 10B. Therefore, the effect of the damping force is small. On the other hand, a damping force is applied to the damping force control cylinder 10A by the damping force valve 14A, but the oil R flowing into the variable valve 24A of the accumulator 23A corresponds to the amount of the rod entering the damping force control cylinder 10B, but a small amount. Therefore, the effect of the damping force is small.

Meanwhile, the oil R flows out from the lower cylinder chamber 10L of the damping force control cylinder 10A incorporated in the right front wheel 2B through the variable valve 11A. The oil R smoothly flows into the upper cylinder chamber 10U of the damping force control cylinder 10B incorporated in the right rear wheel 2D via the check valve 17B. Further, the oil R corresponding to the rod volume discharged from the lower cylinder chamber 10L from the accumulator 23B flows into the upper cylinder chamber 10U via the check valve 25B. At this time, the damping force in the extending direction of the damping force control cylinder 10A is mainly generated by the variable valve 11A in the lower cylinder chamber 10L.

Further, the oil R flows out from the lower cylinder chamber 10L of the damping force control cylinder 10B incorporated in the right rear wheel 2D through the variable valve 11B. The oil R smoothly flows into the upper cylinder chamber 10U of the damping force control cylinder 10A incorporated in the right front wheel 2B via the check valve 17A. Further, the oil R corresponding to the rod volume discharged from the lower cylinder chamber 10L from the accumulator 23A flows into the upper cylinder chamber 10U via the check valve 25A and the check valve 17A. At this time, the damping force in the extending direction of the damping force control cylinder 10B is generated mainly by the variable valve 11B of the lower cylinder chamber 10L.

Thus, the suspension system 100 functions as a suspension with damping force control. Thereby, the suspension system 100 functions as a suspension with damping force control. The acceleration detection unit 30 provided in the vehicle 1 estimates the movement of the vehicle body due to unsprung input (flapping) from the road surface, and optimally controls the damping force in the extending direction of each wheel, thereby varying the fluttering of the wheels 2. Suppressing and improving the ground contact, ensuring ride comfort and running stability. In addition, when a pitching force is input to the vehicle 1, a variable valve 24 provided in the accumulator 23 that exhibits an effect of attenuating the pitch in the hydraulic circuit by detecting the longitudinal direction and the pitch speed by the acceleration detection unit 30. It is controlled by the control unit to attenuate the pitch. When a force in the roll direction is input, the oil R moves between the upper cylinder chamber 10U and the lower cylinder chamber 10L of the damping force control cylinder 10 assembled to the left and right front wheels and the rear wheel, and the roll Therefore, the stabilizer 352 suppresses the roll. Therefore, vehicle stability can be further improved.

1-4. Fourth Embodiment FIG. 21 shows a suspension system 100 according to a fourth embodiment, and is a schematic diagram showing a pair of front wheels (or rear wheels). The suspension system 100 of the present embodiment can be applied to a pair of left and right wheels 2 of at least one of a front wheel and a rear wheel. The left wheel 32A and the right wheel 32B are attached to the vehicle body 9 so as to be rotatable around the rotation axes XA and XB, respectively. The wheel 2 is attached to the vehicle body 9 so as to be movable up and down via the left hydraulic cylinder 4 and the right hydraulic cylinder 5. Specifically, the wheel 2 is attached to the vehicle body 9 via a link member 3 that can swing up and down from the lower end 1 A of the vehicle body 9. The left hydraulic cylinder 4 and the right hydraulic cylinder 5 have upper ends attached to the support portion 1B of the vehicle body 9, and lower ends attached to the intermediate portion 3A of the link member 3, so that the vehicle body 9 and the wheel 2 It is configured so that it can be attenuated by expanding and contracting with respect to the vertical relative movement.

The suspension system 100 according to the present embodiment includes a left hydraulic cylinder 4 and a right hydraulic cylinder 5 that are attached across the left and right support portions 1B of the vehicle body 9 and the intermediate portion 3A of the left and right link members 3, The first oil passage 6 that connects the upper cylinder chamber 4U of the left hydraulic cylinder 4 and the lower cylinder chamber 5L of the right hydraulic cylinder 5 in communication, the upper cylinder chamber 5U of the right hydraulic cylinder 5 and the lower cylinder of the left hydraulic cylinder 4 The second oil passage 7 that communicates with the chamber 4L and the

ports

110 and 111 of the

cylinder chambers

4U, 4L, 5U, and 5L are provided corresponding to the

ports

110 and 111, respectively. A differential pressure mechanism 8 for making a difference in the input / output pressure, and

accumulators

23A and 23B provided in communication with the first oil passage 6 and the second oil passage 7 are provided. That is, the

accumulators

23A and 23B are a pair.

Note that the

accumulators

23A and 23B generate system pressure and supply oil R from the

cylinder chambers

4U, 4L, 5U, and 5L, and conversely supply oil R to the

cylinder chambers

4U, 4L, 5U, and 5L. Moreover, it is provided in order to provide the roll rigidity of the vehicle. The containers of the

accumulators

23A and 23B are filled with gas, and act as a gas spring by changing the volume of the gas according to the volume of the oil R. That is, when the oil R flows into the

accumulators

23A and 23B, the gas is compressed, a repulsive force due to the spring force of the gas is added to the oil R, and the roll rigidity (stabilizer function) of the vehicle can be imparted.

The first oil passage 6 and the accumulator 23A are connected in communication by a third oil passage 311, while the second oil passage 7 and the accumulator 23B are connected in communication by a fourth oil passage 312. The third oil passage 311 and the fourth oil passage 312 are respectively provided with load mechanisms 13 that apply a load when the oil R enters the

accumulators

23A and 23B. Further, between the third oil passage 311 and the fourth oil passage 312, the oil volume between the oil passages increases and decreases, and the balance of the oil R is allowed with respect to the vehicle inclination or the like due to the difference. A communication mechanism 39 is provided.

The upper and lower cylinder chambers of the

hydraulic cylinders

4 and 5 are divided by pistons P, respectively, and the piston rod PR is provided so as to penetrate the

lower cylinder chambers

4L and 5L.

The differential pressure mechanism 8 includes a check valve 8A that allows only the entry of the oil R into the cylinder chamber, and allows only the discharge of the oil R from the cylinder chamber and is opened while the differential pressure exceeds a predetermined pressure value. A damping force valve 8B for adjusting the flow rate based on the pressure and an orifice 8C for providing resistance at the time of discharge are provided. The relationship between the differential pressure of the damping force valve 8B and the flow rate is as shown in FIG.

The check valve 8A and the damping force valve 8B are provided with a spring 15 that applies a closing force to the valve body. When the urging force of the spring 15 is large, the flow resistance of the oil R is increased, and conversely, when the urging force is small, the flow resistance of the oil R may be decreased, or a leaf valve structure may be used. . However, the check valve 8A is not set to a high flow resistance so that the oil R can easily flow in at the time of inflow. The damping force valve 8B changes the valve opening amount in accordance with the flow rate and the differential pressure, and generates a corresponding damping force. For example, the damping force valve 8B is configured to apply an elastic biasing force by a leaf spring or the like in the valve closing direction. Can be used.

In the present embodiment, the differential pressure mechanism 8 is configured such that the flow resistance when the oil R is discharged from the

cylinder chambers

4U, 4L, 5U, and 5L causes the oil R to enter the

cylinder chambers

4U, 4L, 5U, and 5L. It is set larger than the flow resistance. That is, rather than the damping force when the oil R enters the

cylinder chambers

4U, 4L, 5U, and 5L via the check valve 8A, the oil R passes through the

cylinder chambers

4U, 4L, 5U, and the damping force valve 8B. The damping force when discharged from 5L is set larger.

Further, the relationship between the piston speed and the flow resistance (corresponding to the damping force) is controlled by the flow resistance by the orifice 8C when the piston speed is low, as shown in FIG. 23, by the damping force valve 8B and the orifice 8C. When the piston speed increases, the flow resistance changes after the damping force valve 8B is opened. As can be seen from this figure, the appropriate damping desired for the piston speed can be obtained.

As shown in FIG. 21, the load mechanism 13 corresponds to a damping force valve 13A (corresponding to “second valve for accumulator” according to the present invention) and a check valve 13B (corresponding to “first valve for accumulator” according to the present invention). ) And an orifice 13C. The check valve 13B is provided in each

accumulator

23A, 23B so as to discharge the oil R from each

accumulator

23A, 23B. Therefore, the check valve 13B only allows the oil R to be discharged from the

accumulators

23A and 23B. The damping force valve 13A is provided in the

accumulators

23A and 10 so as to adjust the flow rate of the oil R entering the

respective accumulators

23A and 23B. Therefore, the damping force valve 13A allows only the oil R to enter the

accumulators

23A and 23B, and adjusts the flow rate based on the pressure value while the pressure is opened at a predetermined pressure value or more.

The damping force valve 13A and the check valve 13B are provided with springs that apply a closing force to the valve body. When the urging force of the spring is large, the flow resistance of the oil R is increased. Conversely, when the urging force is small, the flow resistance of the oil R may be decreased, or a leaf valve structure may be used. Further, the damping force valve 13A is configured to give a larger load to the oil R than the load of the check valve 13B. That is, the check valve 13B is set to a low flow resistance so that the oil R flows smoothly from the

accumulators

23A and 23B, and the damping force valve 13A is configured to generate an appropriate damping force.

Here, the damping force valve 13A on the accumulator 23A side is configured to apply a load larger than the load applied to the oil R by the check valve 13B on the accumulator 23A side, and the damping force valve 13A on the accumulator 23B side is configured to be an accumulator. The check valve 13B on the 23B side is not limited to the one configured to apply a load larger than the load applied to the oil R. The damping force valve 13A provided in the accumulator 23A applies a larger load than the load applied to the oil R by the check valve 13B provided in the accumulator 23B on the side different from the accumulator 23A provided with the damping force valve 13A. It is also possible to configure. Further, the damping force valve 13A provided in the accumulator 23B has a load larger than the load applied to the oil R by the check valve 13B provided in the accumulator 23A on the side different from the accumulator 23A provided with the damping force valve 13A. It can also be configured to provide.

Further, the damping force valve 13A on the accumulator 23A side is configured to apply a load larger than the load applied to the oil R by the check valve 13B on the accumulator 23A side, and the damping force valve 13A on the accumulator 23B side is configured to be an accumulator. The check valve 13B on the 23B side is configured to apply a load larger than the load applied to the oil R, and the damping force valve 13A provided in the accumulator 23A is a load applied to the oil R by the check valve 13B provided in the accumulator 23B. The damping force valve 13A provided in the accumulator 23B may be configured to apply a load larger than the load applied to the oil R by the check valve 13B provided in the accumulator 23A. This It is possible to.

Further, similarly to the orifice 8C, the orifice 13C can adjust the damping force in a region where the piston speed is low. The orifice 13C is not necessarily required, and may be omitted depending on the performance required for the suspension system 100.

Next, the operation status of the suspension system 100 with respect to the movement of the wheel 2 will be described. As for the movement of the wheel 2, as shown in FIG. 24, both the left hydraulic cylinder 4 and the right hydraulic cylinder 5 extend, and the left hydraulic cylinder 4 and the right hydraulic cylinder 5 as shown in FIG. A “shrink bounce” that shrinks and a “roll” that stretches one of the left hydraulic cylinder 4 and the right hydraulic cylinder 5 as shown in FIG.

“Elongation bounce” occurs when both wheels 2 rebound, and the oil R is discharged from the

lower cylinder chambers

4L and 5L and passes through the corresponding differential pressure mechanisms 8 as shown in FIG. , Flows into the

upper cylinder chambers

5U, 4U of the opposite cylinder. At this time, since the absolute value of the amount of expansion / contraction is equal between the one lower cylinder chamber 4L (5L) and the other upper cylinder chamber 5U (4U), it is discharged from the lower cylinder chamber 4L (5L). The oil R corresponding to the volume of the piston rod PR is smoothly flowed from the accumulator 23B (23A) to the upper cylinder chamber 5U (4U) via the check valve 13B.

In the flow of the oil R described above, a damping force is generated mainly by discharging the oil R via the differential pressure mechanism 8 corresponding to the

lower cylinder chambers

4L and 5L. At this time, the differential pressure mechanism 8 corresponding to the

upper cylinder chambers

4U and 5U has the check valve 8A set so that the oil R flows smoothly in order to ensure a sufficient fluid pressure in the cylinder chamber. Yes.

“Shrink bounce” occurs when both wheels 2 bounce, and the oil R is discharged from the

upper cylinder chambers

4U and 5U as shown in FIG. 25, via the corresponding differential pressure mechanism 8, It flows into the

lower cylinder chambers

5L, 4L of the opposite cylinder. At this time, since the absolute value of the amount of expansion / contraction is equal between one upper cylinder chamber 4U (5U) and the other lower cylinder chamber 5L (4L), the upper cylinder chamber 4U (5U) enters. Oil R corresponding to the volume of the piston rod PR flows into the accumulator 23A (23B) via the load mechanism 13.

In the oil R flow described above, a damping force is generated by discharging the oil R through the differential pressure mechanism 8 corresponding to the

upper cylinder chambers

4U and 5U. At this time, the flow rate of the oil R corresponding to the volume of the rod passing through the load mechanism 13 is small, and the damping force generated by the load mechanism 13 is small. In addition, the differential pressure mechanism 8 corresponding to the

lower cylinder chambers

4L and 5L has a check valve 8A set to a characteristic that allows the oil R to flow smoothly in order to ensure a sufficient fluid pressure in the cylinder chamber.

“Roll” occurs when the vehicle turns to the right or left, and here, the case of turning left will be described. The left wheel 32A (turning inner ring) moves relatively in the rebound direction, and the oil R is discharged from the lower cylinder chamber 4L as shown in FIG. 26, and the corresponding differential pressure mechanism 8 and load mechanism 13 are discharged. And flows into the accumulator 23B. The right wheel 32B (turning outer wheel) moves in the relative bounce direction, and the oil R is discharged from the upper cylinder chamber 5U as shown in FIG. 26, and the corresponding differential pressure mechanism 8 and load mechanism 13 are moved. Via, it flows into the accumulator 23B. At this time, the differential pressure mechanism 8 corresponding to the lower cylinder chamber 4L of the left hydraulic cylinder 4, the differential pressure mechanism 8 corresponding to the upper cylinder chamber 5U of the right hydraulic cylinder 5, and the load mechanism 13 corresponding to the accumulator 23B. Can exhibit a great damping effect.

Oil R is supplied from the accumulator 23A to the upper cylinder chamber 4U of the left hydraulic cylinder 4 and the lower cylinder chamber 5L of the right hydraulic cylinder 5, but the corresponding differential pressure mechanisms 8 are provided on the lower side. In order to ensure sufficient fluid pressure in the cylinder chamber 4L and the upper cylinder chamber 5U, the check valves 8A for the upper cylinder chamber 4U and the lower cylinder chamber 5L are set so that the oil R flows smoothly.

The above-described characteristics of the impact damping force with respect to “elongation bounce”, “shrink bounce”, and “roll” can be expressed as shown in FIG. The broken line indicates “elongation bounce” and “shrink bounce”, the solid line indicates “roll”, the horizontal axis indicates the piston speed, and the vertical axis indicates the damping force. As the piston speed changes, the linearity is bent, and the damping effect by the orifice 8C of the differential pressure mechanism 8 appears in the initial steep area. In the area of gentle gradient, the damping effect by each differential pressure mechanism 8 and load mechanism 13 appears.

According to the suspension system 100 of the present embodiment, “bounce” or “bounce” or “bounce” can be achieved by providing the differential pressure mechanism 8 or the load mechanism 13 according to the vertical movement of the wheel 2 without providing a complicated mechanical mechanism or control mechanism. Good attenuation can be achieved with respect to the “roll”, and it is possible to ensure both running stability and good riding comfort. Further, according to the suspension system 100 of the present embodiment, the absorber function and the stabilizer function can be combined, the stabilizer bar can be omitted, and the structure around the wheel 2 can be simplified.

1-5. Fifth Embodiment Next, a fifth embodiment according to the present invention will be described. FIG. 27 shows the vehicle body 9 incorporating the suspension system 100 of the present embodiment. The suspension system 100 according to the fourth embodiment includes the differential pressure mechanism 8, but the suspension system 100 according to the fifth embodiment includes a suspension mechanism 50 instead of the differential pressure mechanism 8. Different from the embodiment. Below, a different point is mainly demonstrated.

Even in the suspension system 100 of the present embodiment, the left hydraulic cylinder 4 and the right hydraulic cylinder 5 are attached across the left and right support portions 1B of the vehicle body 9 and the intermediate portion 3A of the left and right link members 3. Accordingly, the left hydraulic cylinder 4 and the right hydraulic cylinder 5 are respectively provided between the position where the support portion 1B of the vehicle body 9 is connected and the suspension mechanism 50 when viewed in the horizontal direction. In addition, the upper cylinder chamber 4U of the left hydraulic cylinder 4 and the lower cylinder chamber 5L of the right hydraulic cylinder 5 are connected in communication by the first oil passage 6 so that the upper cylinder chamber 5U of the right hydraulic cylinder 5 and the lower hydraulic cylinder 4 The side cylinder chamber 4 L is connected in communication with the second oil passage 7. The first oil passage 6 and the second oil passage 7 are respectively provided with

accumulators

23A and 23B in communication.

The first oil passage 6 and the accumulator 23A are connected in communication by a third oil passage 311, and the second oil passage 7 and the accumulator 23B are connected in communication by a fourth oil passage 312. The load mechanism 13 is provided in each of the third oil passage 311 and the fourth oil passage 312. A communication mechanism 39 is also provided across the third oil passage 311 and the fourth oil passage 312.

Also in this embodiment, the load mechanism 13 includes a damping force valve 13A, a check valve 13B, and an orifice 13C, and the damping force valve 13A is configured to apply a larger load to the oil R than the load of the check valve 13B. Has been. Thereby, the function of the stabilizer which suppresses the roll of the vehicle body 9 is realized.

Here, as described above, in this embodiment, the differential pressure mechanism 8 that attenuates the bounce of the vehicle body 9 is not provided. Therefore, in the suspension system 100 of the present embodiment, the suspension mechanism 50 is provided to reinforce the absorber function. The suspension mechanism 50 is provided in parallel with each of the left hydraulic cylinder 4 and the right hydraulic cylinder 5 and suspends the wheel 2. The suspension mechanism 50 includes a so-called “shock absorber” including a hydraulic damper 51 and a spring 52. Since a well-known shock absorber can be used, a description of its configuration is omitted. In the present embodiment, a double cylinder type hydraulic damper 51 is used, and a piston valve 60 having a check valve VA1 and a damping force valve VA2 and a base valve 70 having a check valve VA3 and a damping force valve VA4 are provided. The damping force generated by the damping force valve VA4 is set to be larger than the damping force generated by the damping force valve VA2, and the damping force generated by the check valve VA1 and the check valve VA3 is extremely smaller than the damping force generated by the damping force valve VA2. Is set to be

Next, the operation status of the suspension system 100 with respect to the movement of the wheel 2 will be described. As for the movement of the wheel 2, as shown in FIG. 28, both the left hydraulic cylinder 4 and the right hydraulic cylinder 5 extend together, and the left hydraulic cylinder 4 and the right hydraulic cylinder 5 as shown in FIG. The “shrink bounce” that shrinks, the “roll” that one of the left hydraulic cylinder 4 and the right hydraulic cylinder 5 stretches as shown in FIG. 30, and the “shrink bounce” by single wheel input as shown in FIG. Then, “elongation bounce” by single wheel input as shown in FIG. 32 will be described.

“Elongation bounce” occurs when both wheels 2 rebound, and as shown in FIG. 28, oil R is discharged from both

lower cylinder chambers

4L and 5L, and

upper cylinder chambers

5U and 4U of the opposite cylinder. Flow into. At this time, since the absolute value of the amount of expansion / contraction is equal between the one lower cylinder chamber 4L (5L) and the other upper cylinder chamber 5U (4U), it is discharged from the lower cylinder chamber 4L (5L). The oil R corresponding to the volume of the piston rod PR is smoothly flowed from the accumulator 23B (23A) to the upper cylinder chamber 5U (4U) via the check valve 13B. At this time, the hydraulic damper 51 of the suspension mechanism 50 also tends to extend both left and right. For this reason, a damping force is generated by the damping force valve VA2.

As described above, in the “elongation bounce”, almost no damping force is generated by the left hydraulic cylinder 4 and the right hydraulic cylinder 5, but only the damping force by the hydraulic damper 51 of the suspension mechanism 50 is generated. In this way, it is possible to generate an appropriate damping force on the extension side, to secure the grounding property of the vehicle, and to ensure both running stability and good riding comfort.

upper cylinder chambers

4U and 5U and the

lower cylinder chambers

5L and 4L of the opposite cylinder as shown in FIG. Flow into. At this time, since the absolute value of the amount of expansion / contraction is equal between one upper cylinder chamber 4U (5U) and the other lower cylinder chamber 5L (4L), the upper cylinder chamber 4U (5U) enters. Oil R corresponding to the volume of the piston rod PR flows into the accumulator 23A (23B) via the load mechanism 13. At this time, the flow rate of the oil R corresponding to the volume of the rod passing through the load mechanism 13 is small, and the damping force generated by the load mechanism 13 is small. At this time, the hydraulic damper 51 of the suspension mechanism 50 also tries to contract both left and right. For this reason, a damping force is generated by the damping force valve VA4.

As described above, in the “shrink bounce”, almost no damping force is generated by the left hydraulic cylinder 4 and the right hydraulic cylinder 5, but only the damping force by the hydraulic damper 51 of the suspension mechanism 50 is generated. In this way, it is possible to generate an appropriate damping force on the contraction side, to ensure the grounding property of the vehicle, and to ensure both running stability and good riding comfort.

“Roll” occurs when the vehicle turns to the right or left, and here, the case of turning right will be described. The left wheel 32A (turning outer wheel) moves relatively in the bounce direction, and the oil R is discharged from the upper cylinder chamber 4U and flows into the accumulator 23A via the load mechanism 13, as shown in FIG. . The right wheel 32B (turning inner ring) moves relatively in the rebound direction, and the oil R is discharged from the lower cylinder chamber 5L and flows into the accumulator 23A via the load mechanism 13, as shown in FIG. To do. At this time, the damping force valve 13A of the load mechanism 13 can exert a great damping effect.

Also, the oil R is smoothly supplied from the accumulator 23B to the lower cylinder chamber 4L of the left hydraulic cylinder 4 and the upper cylinder chamber 5U of the right hydraulic cylinder 5.

At this time, the hydraulic damper 51 on the left wheel 32A side strokes in the contracting direction, and the hydraulic damper 51 on the right wheel 32B side strokes in the extending direction. Therefore, a damping force is generated by the damping force valve VA4 in the hydraulic damper 51 on the left wheel 32A side, and a damping force is generated by the damping force valve VA2 in the hydraulic damper 51 on the right wheel 32B side.

As described above, the “roll” acts so that the damping force by the hydraulic damper 51 of the suspension mechanism 50 is added to the damping force by the left hydraulic cylinder 4 and the right hydraulic cylinder 5. In this way, it is possible to increase the damping force on the roll to suppress the roll, to ensure the grounding property of the vehicle, and to ensure both running stability and good riding comfort.

“Single-wheel input“ shrink bounce ”occurs when one of the left and right wheels 2 bounces when the left or right wheel 2 gets over a protrusion. Here, a case will be described in which the left wheel 32A gets over a protrusion or the like. The left wheel 32A moves in the bound direction, and in this case, as shown in FIG. 31, the right wheel 32B hardly strokes. Since the lower cylinder chamber 5L of the right hydraulic cylinder 5 needs to have enough pressure to compress and retract the coil, the oil R discharged from the upper cylinder chamber 4U of the left hydraulic cylinder 4 hardly flows and passes through the load mechanism 13. Then, it flows into the accumulator 23A. At this time, a damping force corresponding to the stroke amount and the stroke speed is generated by the damping force valve 13A of the load mechanism 13.

Further, the oil R is smoothly supplied from the accumulator 23B to the lower cylinder chamber 4L of the left hydraulic cylinder 4. In this example, since there is almost no inflow of oil R into the lower cylinder chamber 5L and outflow of oil R from the upper cylinder chamber 5U, the flow of these oil R is shown in FIG. 31 for easy understanding. It is indicated by a broken line.

At this time, the hydraulic damper 51 on the left wheel 32A side strokes in the contraction direction, but the hydraulic damper 51 on the right wheel 32B side hardly moves. For this reason, in the hydraulic damper 51 on the left wheel 32A side, a damping force corresponding to the stroke amount and the stroke speed is generated by the damping force valve VA4.

As described above, in the “shrink bounce” of the single wheel input, the damping force by the damping force valve 13A of the load mechanism 13 on the accumulator 23A side, the damping force by the damping force valve VA4 of the hydraulic damper 51 on the left wheel 32A side, and Will occur. Thus, the damping force is generated, the grounding property of the vehicle is ensured, and both the running stability and the good riding comfort can be achieved.

“Elongation bounce” for single wheel input occurs when either the left or right wheel 2 rebounds when passing through a depression or the like with either of the left or right wheel 2. Here, a case where the left wheel 32A passes through a depression or the like will be described. The left wheel 32A moves in the rebound direction. In this case, as shown in FIG. 32, the right wheel 32B hardly strokes. Since the upper cylinder chamber 5U of the right hydraulic cylinder 5 needs pressure to lift the vehicle body 9, the oil R discharged from the lower cylinder chamber 4L of the left hydraulic cylinder 4 hardly flows and passes through the load mechanism 13. Flows into the accumulator 23B. At this time, a damping force corresponding to the stroke amount and the stroke speed is generated by the damping force valve 13A of the load mechanism 13.

Further, the oil R is smoothly supplied from the accumulator 23A to the upper cylinder chamber 4U of the left hydraulic cylinder 4. In this example, since there is almost no outflow of oil R from the lower cylinder chamber 5L and inflow of oil R into the upper cylinder chamber 5U, the flow of these oil R is shown in FIG. 32 for easy understanding. It is indicated by a broken line.

At this time, the hydraulic damper 51 on the left wheel 32A side strokes in the extending direction, but the hydraulic damper 51 on the right wheel 32B side hardly moves. For this reason, in the hydraulic damper 51 on the left wheel 32A side, a damping force corresponding to the stroke amount and the stroke speed is generated by the damping force valve VA2.

As described above, in the “elongation bounce” of the single-wheel input, the damping force by the damping force valve 13A of the load mechanism 13 on the accumulator 23B side and the damping force by the damping force valve VA2 of the hydraulic damper 51 on the left wheel 32A side are Will occur. Thus, the damping force is generated, the grounding property of the vehicle is ensured, and both the running stability and the good riding comfort can be achieved.

1-6. Sixth Embodiment Next, a sixth embodiment according to the present invention will be described. FIG. 33 shows a vehicle body 9 incorporating the suspension system 100 of the present embodiment. The suspension system 100 of the fourth embodiment has been described as including the differential pressure mechanism 8. The suspension system 100 according to the fifth embodiment has been described as including the suspension mechanism 50 instead of the differential pressure mechanism 8. The suspension system 100 according to the sixth embodiment differs from the fourth and fifth embodiments in that both the differential pressure mechanism 8 and the suspension mechanism 50 are provided. Since the configuration is the same as in the fourth and fifth embodiments, description thereof is omitted.

Even with such a configuration, it is possible to appropriately generate a damping force in accordance with the state of the vehicle, as in the fourth and fifth embodiments. Therefore, it is possible to ensure the grounding property of the vehicle, and to ensure both running stability and good riding comfort.

2. Next, the structure of the hydraulic cylinder used for the left hydraulic cylinder 4 and the right hydraulic cylinder 5 will be described. The left hydraulic cylinder 4 and the right hydraulic cylinder 5 can be the same. Therefore, in the following, an example of the left hydraulic cylinder 4 will be described. A cross-sectional view schematically showing the configuration of the left hydraulic cylinder 4 is shown in FIG. In the first to third embodiments, it is naturally possible to apply a hydraulic cylinder having a configuration described below to the damping force control cylinder 10A and the damping force control cylinder 10B.

The left hydraulic cylinder 4 includes an outer cylinder 41, an inner cylinder 42, a piston P, and a piston rod PR. The outer cylinder 41 and the inner cylinder 42 are formed in a cylindrical shape, and are formed so that the outer diameter of the inner cylinder 42 is smaller than the inner diameter of the outer cylinder 41. The outer cylinder 41 and the inner cylinder 42 are arranged coaxially. Therefore, an annular space 90 is formed between the inner peripheral surface of the outer cylinder 41 and the outer peripheral surface of the inner cylinder 42.

The lid 80 is welded so that one side in the axial direction of the outer cylinder 41 is closed. A cylindrical axially extending part 81 extending toward the axially central side of the outer cylinder 41 is formed inside the lid part 80, and the inner cylinder 42 is fitted into the axially extending part 81. Positioned. On the inner peripheral surface of the axially extending portion 81, a seal member 85 is provided at a portion that contacts the outer peripheral surface of the inner cylinder 42. As a result, it is possible to liquid-tightly configure one side of the annular space 90 in the axial direction. Here, a fixing portion 101 for attaching the left hydraulic cylinder 4 to the link member 3 is welded to the outside (axially outside) of the lid portion 80.

A first cap member 82 is fitted on the other side in the axial direction of the inner cylinder 42 so that the outer peripheral surface is in contact with the inner peripheral surface of the outer cylinder 41, and is positioned with respect to the inner peripheral surface of the outer cylinder 41. Is done. The first cap member 82 is supported by the second cap member 83 from the outside in the axial direction (the side opposite to the fixed portion 101). The outer peripheral surface of the second cap member 83 is provided in contact with the inner peripheral surface of the outer cylinder 41. A Teflon (registered trademark) rod seal 84 is disposed on the radially inner side of the second cap member 83 via an O-ring 131. Thereby, the sealing performance can be enhanced while reducing the sliding resistance when the piston rod PR slides. A seal member 86 is disposed on the outer peripheral surface of the second cap member 83. Thereby, it becomes possible to form between the 2nd cap member 83 and the outer cylinder 41 liquid-tightly.

By configuring as described above, the annular space 90 can be configured in a liquid-tight manner. In the annular space 90, oil or air is sealed in a liquid-tight manner. Thereby, the heat insulation of the left hydraulic cylinder 4 can be improved. It is also possible to prevent distortion of the sliding surface (outer peripheral surface) of the piston P due to a stepping stone from the outside.

The inner side of the inner cylinder 42 is provided with a piston P coaxially and a piston rod PR that is fixed to the piston P on one side in the axial direction. The piston rod PR is formed so that its outer diameter is smaller than the inner diameter of the inner cylinder 42 and its outer peripheral surface is slidable on the inner peripheral surfaces of the first cap member 82 and the second cap member 83. A region surrounded by the inner peripheral surface of the inner cylinder 42, the piston P, and the lid 80 corresponds to the lower cylinder chamber 4L.

In the piston rod PR, a cylindrical tube 93 (corresponding to the “tubular member” of the present invention) is disposed coaxially on the radially inner side. A cap 94 is fastened and fixed to the other side of the piston rod PR with a screw. The cap 94 is formed with a port 111 for supplying and discharging oil R from the upper cylinder chamber 4U and a port 110 for supplying and discharging oil R from the lower cylinder chamber 4L. The cap 94 is welded with a fixing portion 102 for attaching the left hydraulic cylinder 4 to the support portion 1B of the vehicle body 9. Therefore, the

ports

110 and 111 can be disposed at positions separated from the lower fixing portion 101.

As described above, the piston rod PR is fastened and fixed by the cap 94. For this reason, the fixing | fixed part 102 is corresponded to the fixing | fixed part of piston rod PR provided in the upper side. Therefore, in this embodiment, the

ports

110 and 111 can be disposed on the fixed portion 102 side of the piston rod PR.

One side of the pipe 93 in the axial direction is inserted through the piston P, and is communicated with the lower cylinder chamber 4L through a space inside the pipe 93 in the radial direction. The space on the radially inner side of the pipe 93 serves as a lower cylinder chamber oil passage 171 for supplying and discharging the oil R in the lower cylinder chamber 4L. The other axial side of the pipe 93, that is, the other axial side of the lower cylinder chamber oil passage 171 is communicated with the port 110 via the radial oil passage 181. The space surrounded by the outer peripheral surface of the pipe 93, the inner peripheral surface of the inner cylinder 42, the piston P, and the first cap member 82 corresponds to the upper cylinder chamber 4U.

An annular space is formed between the outer peripheral surface of the pipe 93 and the inner peripheral surface of the piston rod PR. One side of this annular space communicates with the upper cylinder chamber 4 U via the radial oil passage 182, and the other side communicates with the port 111. Therefore, this annular space becomes the upper cylinder chamber oil passage 170 for supplying and discharging the oil R. As described above, in the present embodiment, the upper cylinder chamber oil passage 170 and the lower cylinder chamber oil passage 171 are provided on the radially inner side of the piston rod PR.

The upper cylinder chamber 4U and the lower cylinder chamber 4L are filled with oil R, and the volumes of the upper cylinder chamber 4U and the lower cylinder chamber 4L change as the piston P moves in the inner cylinder 42. In response to this change, oil R is supplied and discharged from the

ports

110 and 111. In accordance with the movement of the piston P, the piston rod PR also moves along the axial direction. For this reason, the bush 120 is disposed at a position facing the outer peripheral surface of the piston rod PR of the first cap member 82.

A small-diameter portion 41A that reduces the inner diameter is formed at the axial end of the outer cylinder 41. A disk-shaped iron plate 150 is disposed on the axial position side (the second cap member 83 side) of the small diameter portion 41A. The iron plate 150 is positioned with its outer peripheral surface in contact with the inner peripheral surface of the outer cylinder 41. A rubber member 151 attached to the iron plate 150 is disposed on the radially inner side of the small diameter portion 41A, and a metal spring 152 that biases the rubber member 151 radially inward is disposed on the outer peripheral surface of the rubber member 151. Has been. Thereby, the penetration | invasion of the dust from the outside through the radial inside of the small diameter part 41A can be prevented.

A disc-shaped iron plate 140 is disposed on the axial end surface of the iron plate 150 on the second cap member 83 side. The outer peripheral surface of the iron plate 140 is positioned in contact with the inner peripheral surface of the outer cylinder 41. A rubber seal member 121 is disposed on the inner peripheral surface of the iron plate 140 and the axial end surface on the second cap member 83 side. The seal member 121 extends in the axial direction along the piston rod PR. This extending portion is urged radially inward by the metal spring 142 from the radially outer side. In addition, a resin bush 191 is disposed on the radially inner side of the seal member 121 on which the iron plate 140 is disposed on the radially outer side. Thereby, the sealing performance especially at the time of low pressure can be enhanced, and the oil R in the left hydraulic cylinder 4 can be prevented from leaking through the outer peripheral surface of the piston rod PR. Therefore, the oil R can be prevented from leaking outside. With the above configuration, the piston rod PR can move coaxially with the piston P.

A cover member 160 is disposed on the cap 94 so as to cover at least part of the outer peripheral surface of the piston rod PR and the outer cylinder 41. Thereby, it becomes possible to protect the outer peripheral surface of the piston rod PR from dust or the like.

3. Other Embodiments In the first to third embodiments, the acceleration detection unit 30 that detects the vertical acceleration of the vehicle body of the vehicle 1 is provided, and the variable valve 11 is based on the detection result of the acceleration detection unit 30. It has been described that the opening area is adjusted. However, the scope of application of the present invention is not limited to this. A method other than the acceleration detection unit 30, for example, a configuration in which the stroke amount of the wheel is detected and the opening area of the variable valve 11 is adjusted based on the detected result may be employed. Of course, it is naturally possible to use other methods.

In the first to third embodiments, the damping force valve 14 is illustrated as a mechanical valve. However, the scope of application of the present invention is not limited to this. It is naturally possible to provide an electromagnetic variable valve in the upper cylinder chamber 10U as well as the lower cylinder chamber 10L.

In the first to third embodiments, the inflow side valve of the accumulator 23 is described as the variable valve 24. However, the scope of application of the present invention is not limited to this. Naturally, the valve on the inflow side of the accumulator 23 can be constituted by a mechanical valve (damping force valve). In such a case, an orifice is provided in parallel with the mechanical valve (damping force valve) and the check valve 25 so that each of the first communication path 21 and the second communication path 22 does not become negative pressure. As a result, the accumulator 23 can communicate with each of the first communication path 21 and the second communication path 22.

The differential pressure mechanism 8 and the load mechanism 13 in the fourth embodiment are not limited to being individually formed, and for example, as shown in FIG. It may be. The unit Y can be installed simply by providing the oil passage connection portions 16 corresponding to the respective ports and connecting each oil passage to the oil passage connection portion 16. In this way, by integrating the differential pressure mechanism 8 and the load mechanism 13 as a unit, exposure of parts such as valves can be prevented to improve the durability of the parts, and the attachment of the unit Y to the vehicle body 9 can be improved. It can be improved and space saving can be realized.

The differential pressure mechanism 8 and the load mechanism 13 are not limited to the specific configuration described in the previous embodiment, and may include a configuration for electrically controlling the valve opening state.

In the above embodiment, the configuration of the left hydraulic cylinder 4 (right hydraulic cylinder 5) is schematically shown in FIG. However, the scope of application of the present invention is not limited to this. For example, as shown in FIG. 36, the present invention can naturally be applied to a hydraulic cylinder included in the McPherson-Strut type suspension mechanism 50. In such a case, it is preferable that the bracket 202 is used instead of the fixing portion 102 to fasten and fix to the vehicle body 9. It is also possible to fasten and fix the cap 94 and the pipe 93 with the nut 203.

In the fourth and fifth embodiments, an example in which the suspension system 100 is provided on a front wheel has been described. However, the scope of application of the present invention is not limited to this. The present invention can be applied to the rear wheel, and naturally can be applied to both the front wheel and the rear wheel.

In the fourth to sixth embodiments, it has been described that the accumulator first valve 13B is a check valve and the accumulator second valve 13A is a damping force valve. However, the scope of application of the present invention is not limited to this. In other words, the first valve 13B for the accumulator is not a check valve, and can naturally be constituted by a damping force valve that applies a load smaller than the load of the damping force valve as the second valve 13A for the accumulator.

Here, the suspension system 100 according to the fourth to sixth embodiments includes a left hydraulic cylinder interposed between the left wheel 32A and the vehicle body 9 in the pair of left and right wheels 2 of at least one of the front wheel and the rear wheel. 4, a right hydraulic cylinder 5 interposed between the right wheel 32 B and the vehicle body 9, a first oil that communicates and connects the upper cylinder chamber 4 U of the left hydraulic cylinder 4 and the lower cylinder chamber 5 L of the right hydraulic cylinder 5. The passage 6 communicates with a second oil passage 7 communicatively connecting the upper cylinder chamber 5U of the right hydraulic cylinder 5 and the lower cylinder chamber 4L of the left hydraulic cylinder 4, and the first oil passage 6 and the second oil passage 7.

Accumulators

23A, 23B respectively provided in the state, and first accumulator valves provided in the

accumulators

23A, 23B so as to discharge the oil R from the

respective accumulators

23A, 23B. 13B and the flow rate of the oil R entering the

respective accumulators

23A and 23B is adjusted to each of the

accumulators

23A and 23B so that the load applied to the oil R is greater than the load applied to the oil R by the first accumulator valve 13B. It can be described that the second valve 13A for the accumulator is provided.

With such a configuration, when a roll is generated in the vehicle body 9, the oil R flowing out from the left and right cylinder chambers passes through the accumulator second valve 13A, and a large resistance pressure acts. As a result, a large damper effect acts on the

hydraulic cylinders

4 and 5, the roll of the vehicle body 9 can be suppressed, and traveling stability can be easily ensured. The stabilizer function by this structure makes it possible to omit the conventional stabilizer bar.

In addition, each of the

ports

110 and 111 in each cylinder chamber may be provided corresponding to each of the ports, and each

port

110 and 111 may be configured to include a differential pressure mechanism 8 that makes a difference in the input / output pressure of the oil R. .

With such a configuration, when bounce occurs in the vehicle body 9, a smaller resistance pressure acts on the oil R passing through the

ports

110 and 111 in a predetermined direction than when rolling. The differential pressure mechanism 8 can be actuated. As a result, the bounce of the vehicle body 9 can be attenuated by the damper effect of the

hydraulic cylinders

4 and 5, and a good riding comfort can be obtained. According to this configuration, it is possible to provide an absorber function, so that the conventional absorber can be omitted or downsized, and the conventional stabilizer bar can be omitted by having the above-described stabilizer function. In addition, the structure around the wheel 2 can be simplified.

When the vehicle body 9 rolls, the lower cylinder chamber 4L (5L) of one hydraulic cylinder 4 (5) and the upper cylinder chamber 5U (4U) of the other hydraulic cylinder 5 (4) communicating therewith. Since both of them contract and cause a volume reduction, the oil R is pushed out from both cylinder chambers and moves to one accumulator 23B (23A). In the present invention, since the second valve 13A for accumulator is provided to apply a load when the oil R enters the accumulator 23B (23A), the cylinder together with the second valve 13A for accumulator at the time of such movement of the oil R is provided. The differential pressure mechanism 8 corresponding to each of the

ports

110 and 111 can also generate a flow resistance, and as a result, the damping effect on the roll of the vehicle body 9 can be exerted more strongly. As a result of the above, it is possible to exert a damping force suitable for rolling and bounce of the vehicle body 9 in a passive system without providing a complicated mechanical mechanism and control mechanism, ensuring traveling stability, It is possible to achieve a good ride comfort together.

Further, the differential pressure mechanism 8 can be configured such that the set pressure when the oil R is discharged from the cylinder chamber is set to be larger than the set pressure when the oil R enters the cylinder chamber.

With this configuration, the damping force can be increased when the oil R is discharged from the cylinder chamber, while the oil R can enter smoothly when the oil R enters the cylinder chamber. It is possible to effectively generate a damping force suitable for suppressing rolls and bounces.

Further, the differential pressure mechanism 8 may be provided with an orifice 8C, a check valve 8A, and a damping force valve 8B that generates a damping force by applying a load to the oil R when the oil R is discharged from the cylinder chamber.

According to such a configuration, it is possible to generate appropriate damping force characteristics with respect to the input from the road surface by effectively using the resistance characteristics of the orifice 8C and the damping force valve 8B. Therefore, for example, when the input speed acting on the hydraulic cylinder is slow, the orifice 8C mainly performs the damping, and when the input speed is fast, the shock is attenuated by the damping force valve 8B in addition to the orifice 8C. It becomes possible. As a result, it is possible to achieve appropriate attenuation regardless of the magnitude of the road surface input acting on the wheel 2, and it is possible to achieve both running stability and improved riding comfort.

It is also possible to unitize the differential pressure mechanism 8 and the load mechanism 13 having the first accumulator valve 13B and the second accumulator valve 13A.

According to such a characteristic configuration, the differential pressure mechanism 8 and the load mechanism 13 are unitized, so that the number of parts such as pipes can be reduced, the attachment to the vehicle body 9 can be improved, and the space can be saved. Can be realized. Moreover, it becomes easy to prevent parts, such as each valve which comprises the differential pressure mechanism 8 and the load mechanism 13, from being exposed, and it can aim at the improvement of component durability.

The second valve 13A for accumulator is supplied to the oil R by the first valve 13B for accumulator provided in the accumulator 23B (23A) on the side different from the accumulator 23A (23B) provided for the second valve 13A for accumulator. It is also possible to provide a load that is greater than the load.

With such a configuration, the damper effect acting on the hydraulic cylinder can be increased, so that the roll of the vehicle body 9 can be suppressed and the running stability can be easily ensured.

Further, a suspension mechanism 50 for suspending the wheel 2 may be provided.

With such a configuration, it is possible to increase the level of roll damping, rigidity, etc. of the vehicle 1, and the range of damping force tuning such as rolls, bounces, etc. is widened. Miniaturization of 100 and mounting flexibility are also improved.

As mentioned above, although the code | symbol was written in order to make contrast with drawing convenient, this invention is not limited to the structure of an accompanying drawing by this entry. In addition, it goes without saying that the present invention can be carried out in various modes without departing from the gist of the present invention.

The present invention can be used for a suspension system that improves the ride comfort and handling stability of a vehicle.

1: Vehicle 2: Wheel 9: Vehicle body 4: Left hydraulic cylinder 4L: Lower cylinder chamber 4U: Upper cylinder chamber 5: Right hydraulic cylinder 5L: Lower cylinder chamber 5U: Upper cylinder chamber 10: Damping force control cylinder 10A: One Damping force control cylinder 10B: the other damping force control cylinder 10U: upper cylinder chamber 10L: lower cylinder chamber 11: variable valve 21: first communication path 22: second communication path 23: accumulator (oil receiving portion)
24: Variable valve 25: Check valve 30: Acceleration detector 32A: Left wheel 32B: Right wheel 93: Tube (tubular member)
DESCRIPTION OF SYMBOLS 100: Suspension system 101: Fixed part 102: Fixed part 110: Port 111: Port 170: Oil path for upper cylinder chamber 171: Oil path for lower cylinder chamber PR: Rod R: Oil

Claims

The upper cylinder chamber that increases in volume when expanded and decreases in volume when contracted, the lower cylinder chamber that decreases in volume when expanded and increases in volume when contracted, and the flow rate of oil flowing out of the lower cylinder chamber A variable valve that adjusts based on the detection result of the detection unit that detects the physical quantity of, a damping force control cylinder incorporated in a pair of wheels among a plurality of wheels of the vehicle,
A first communication passage communicating the upper cylinder chamber of one damping force control cylinder and the lower cylinder chamber of the other damping force control cylinder;
A second communication passage communicating the lower cylinder chamber of the one damping force control cylinder and the upper cylinder chamber of the other damping force control cylinder;
A pair of oil receivers that are provided in each of the first communication path and the second communication path and store and discharge oil in the first communication path and the second communication path according to the operation of the damping force control cylinder. And
Suspension system comprising.
An acceleration detection unit for detecting acceleration in a vertical direction of the vehicle body;
The suspension system according to claim 1, wherein the variable valve adjusts a flow rate of the oil based on a detection result of the acceleration detection unit.
The suspension system according to claim 1 or 2, wherein the oil receiving portion is an accumulator.
The suspension system according to claim 3, further comprising a variable valve that restricts a flow rate of the oil flowing into the accumulator.
The suspension system according to claim 4, wherein a check valve is provided in parallel with a variable valve that restricts a flow rate of oil flowing into the accumulator.
The suspension system according to any one of claims 1 to 5, wherein the pair of wheels are a left wheel and a right wheel provided to face each other in the width direction of the vehicle.
The suspension system according to any one of claims 1 to 5, wherein the pair of wheels are a front wheel and a rear wheel provided in a front-rear direction of the vehicle.
The left hydraulic cylinder interposed between the left wheel and the vehicle body and the right hydraulic cylinder interposed between the right wheel and the vehicle body each receive oil from the upper cylinder chamber and the lower cylinder chamber. The suspension system according to claim 6, wherein the supply / exhaust port is disposed at a position separated from the lower fixing portion.
The port for supplying and discharging oil in the upper cylinder chamber and the port for supplying and discharging oil in the lower cylinder chamber are disposed on the side of the fixed portion of the rod provided on the upper side. The suspension system according to claim 8.
An upper cylinder chamber oil passage for supplying and discharging oil in the upper cylinder chamber and a lower cylinder chamber oil passage for supplying and discharging oil in the lower cylinder chamber are provided on the radially inner side of the rod. The suspension system according to claim 9.
The rod has a cylindrical member coaxially on the radially inner side, the lower cylinder chamber oil passage is formed on the radially inner side of the cylindrical member, and the inner circumferential surface of the rod and the cylindrical member The suspension system according to claim 10, wherein the upper cylinder chamber oil passage is formed between the outer peripheral surface of the upper cylinder chamber.