JP4200883B2 - Suspension system - Google Patents

Description

  The present invention relates to control of vehicle behavior in a suspension system.

Patent Document 1 discloses a shock absorber provided corresponding to each of the front, rear, left and right wheels, and a communication adjusting device provided between two of these four shock absorbers or between four shock absorbers. A suspension system including a pressure regulating device is described. When the pressure adjusting device is provided between the left and right shock absorbers on the front wheel side and the rear wheel side, the roll is suppressed, and when it is provided between the front and rear shock absorbers, the pitch is suppressed, When it is provided between the wheels in the diagonal position, the behavior of combining rolls, pitches, rolls and pitches is suppressed.
In addition, when it is installed between the shock absorber on the right front and rear wheels and the shock absorber on the left front and rear wheels, rolls are suppressed and the front wheels and rear wheels are viewed from the front of the vehicle body. A behavior that twists in the left-right direction is allowed.
Japanese Patent Laid-Open No. 8-132846

  The present invention is an improvement of the suspension system, for example, in a state in which the roll and pitch are suppressed, the wheels that are diagonal to each other among the front, rear, left, and right wheels are in phase in the vertical direction and are in diagonal positions with each other Switch between allowing and suppressing two wheels belonging to one of two sets of wheels and two wheels belonging to the other moving in opposite phases (hereinafter referred to as articulation). In a suspension system in which hydraulic cylinders provided on front, rear, left and right wheels are connected to each other through a communication path, it is possible to suppress rolls and pitches and allow articulation.

In the first aspect of the present invention, the suspension system provided between the front and rear, left and right wheels of the vehicle and the vehicle body includes hydraulic cylinders respectively provided corresponding to the front and rear and left and right wheels; A first movable member is provided that is movable when the hydraulic pressure of the hydraulic cylinder of the right front wheel and the hydraulic cylinder of the left rear wheel of the front, rear, left and right hydraulic cylinders change in the same direction. Separate from the first actuating device and (b) the first movable member movable when the hydraulic pressure of the hydraulic cylinder of the left front wheel and the hydraulic pressure of the hydraulic cylinder of the right rear wheel change in the same direction A second actuating device including a second movable member of the body, and in a state of suppressing the roll and pitch of the vehicle, the state allowing the movement of the first movable member and the second movable member; In a state of preventing movement of the first movable member and the second movable member By switching, the two wheels belonging to one of the two pairs of the front and rear, left and right wheels that are diagonally positioned in the same direction in the vertical direction and that are mutually diagonally positioned A suspension control device that can be switched between a state in which the two wheels belonging to the other are allowed to move in opposite phases and a state in which the movement is suppressed is included.
In articulation, two wheels belonging to each of the two sets of wheels that are diagonally positioned to each other are in phase in the vertical direction, and belong to the two wheels belonging to one set and the other set The two wheels move in opposite phases. To move in reverse phase means that two wheels belonging to one set move upward or downward relative to two wheels of the other set, and two wheels belonging to one set go upward. Typically, the other two wheels move downward while moving, but a special case includes a case where only one set of two wheels moves upward or downward. In other words, the direction of change in the relative distance between the wheel side member and the vehicle body side member for the two wheels in one set and the relative relationship between the wheel side member and the vehicle body side member for the two wheels in the other set. The case where the direction of the distance change is opposite, the case where only the relative distance of the wheels belonging to one set changes, and the like are applicable.
In the suspension system according to the first aspect, in a state where the roll and the pitch are suppressed, the state can be switched between a state where the articulation is allowed and a state where the articulation is suppressed.
For example, if articulation is allowed in a state where rolls and pitches are suppressed, it is possible to suppress a decrease in ride comfort due to road surface input while ensuring running stability and to suppress articulation. By doing so, it is possible to improve running stability during turning and when acceleration is large.

Patentable invention

  In the following, the invention that is claimed to be claimable in the present application (hereinafter referred to as “claimable invention”. The claimable invention is at least the “present invention” to the invention described in the claims. Some aspects of the present invention, including subordinate concept inventions of the present invention, superordinate concepts of the present invention, or inventions of different concepts) will be illustrated and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is for the purpose of facilitating the understanding of the claimable invention, and is not intended to limit the combinations of the constituent elements constituting the claimable invention to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

(1) A suspension system provided between the front and rear wheels and the vehicle body of the vehicle,
Hydraulic cylinders respectively provided corresponding to the front, rear, left and right wheels;
(a) The first movable member that is movable when the hydraulic pressure of the right front wheel hydraulic cylinder and the hydraulic pressure of the left rear wheel hydraulic cylinder change in the same direction among the front, rear, left and right hydraulic cylinders. And (b) the first movable member movable when the hydraulic pressure of the hydraulic cylinder of the left front wheel and the hydraulic cylinder of the right rear wheel change in the same direction. And a second actuating device having a second movable member that is separate from the first movable member and permitting movement of the first movable member and the second movable member in a state where the roll and pitch of the vehicle are suppressed. By switching between the state and the state in which the movement of the first movable member and the second movable member is prevented, the wheels in the diagonal position among the front, rear, left and right wheels are in phase in the vertical direction, and , Two belonging to one of the two sets of wheels that are diagonal to each other Two and is a state that allows the movement in the opposite phase and the suspension controller capable of switching on and the inhibit movement state wheels belonging to wheels and other
A suspension system comprising: (Claim 1).
(2) The suspension control device allows movement of the first and second movable members by controlling the state of hydraulic fluid exchange between the first operating device and the second operating device. The suspension system according to item (1), including an operating state switching device capable of switching between a state and a blocking state.
If the movement of the first movable member and the second movable member is allowed, the articulation is allowed, and the movement is prevented, the articulation is suppressed.
It can be considered that the articulation control device is constituted by the first operating device, the second operating device, the operating state switching device, and the like.
(3) The first movable member is a stepped piston fitted in a housing in a liquid-tight and slidable manner. In the first operating device, two first movable members provided in the same direction of the first movable member. The hydraulic cylinder for the left front wheel and the hydraulic cylinder for the right rear wheel are respectively connected to the pressure receiving surface in a state where the hydraulic pressure acts, and a liquid chamber facing the remaining pressure receiving surface is first. It is a volume change chamber, and the second movable member is a stepped piston that is liquid-tightly and slidably fitted to the housing. In the second operating device, the second movable member is provided in the same direction as the second movable member. In addition, the hydraulic cylinder for the right front wheel and the hydraulic cylinder for the left rear wheel are respectively connected to the two pressure receiving surfaces in a state in which the hydraulic pressure acts, and the liquid chambers that face the remaining pressure receiving surfaces Is the second volume change chamber, and the operating state switching device is (a) an electromagnetic valve provided in a liquid passage connecting the first volume change chamber and the second volume change chamber; and (b) a current supplied to a solenoid of the electromagnetic valve by controlling these currents. The suspension system according to the item (2), further including a flow state control device that switches between a state in which the flow of the hydraulic fluid is allowed and a state in which it is blocked.
The first actuating device is provided between the hydraulic cylinder for the left front wheel and the hydraulic cylinder for the right rear wheel. For example, in the first actuating device, the hydraulic pressure of the hydraulic cylinder of the left front wheel acts on one of the pressure receiving surface on the small diameter side of the first movable member and the pressure receiving surface of the stepped portion, and the liquid on the right rear wheel acts on the other. The hydraulic cylinders of the left front wheel and the right rear wheel are connected in a state where the hydraulic pressure of the pressure cylinder acts.
The second actuating device is provided between the hydraulic cylinder for the right front wheel and the hydraulic cylinder for the left rear wheel. For example, the hydraulic pressure of the hydraulic cylinder of the right front wheel acts on one of the pressure receiving surface on the small diameter side of the second movable member and the pressure receiving surface of the stepped portion, and the hydraulic pressure of the hydraulic cylinder of the left rear wheel acts on the other. In this state, hydraulic cylinders for the right front wheel and the left rear wheel are connected.
In a state where the flow of hydraulic fluid is allowed between the first volume change chamber and the second volume change chamber, the movement of the first and second movable members is allowed and articulation is allowed.
In a state where the flow of the hydraulic fluid is blocked between the first volume change chamber and the second volume change chamber, the movement of the first and second movable members is blocked and the articulation is suppressed.
(4) The suspension system according to (3 ), wherein the flow state control device includes a solenoid valve control unit that controls a flow state between the solenoid valves by controlling a current supplied to a solenoid of the solenoid valve.
The solenoid valve may be an electromagnetic on-off valve that can be switched between open and closed states by turning on and off the current supplied to the solenoid, or an electromagnetic linear control valve that can change the flow area in the open state. it can.
(5) The first movable member is a stepped piston fitted in a housing in a liquid-tight and slidable manner. In the first operating device, two first movable members provided in the same direction of the first movable member. The hydraulic cylinder for the left front wheel and the hydraulic cylinder for the right rear wheel are respectively connected to the pressure receiving surface in a state where the hydraulic pressure acts, and a liquid chamber facing the remaining pressure receiving surface is first. It is a volume change chamber, and the second movable member is a stepped piston that is liquid-tightly and slidably fitted to the housing. In the second operating device, the second movable member is provided in the same direction as the second movable member. In addition, the hydraulic cylinder for the right front wheel and the hydraulic cylinder for the left rear wheel are respectively connected to the two pressure receiving surfaces in a state in which the hydraulic pressure acts, and the liquid chambers that face the remaining pressure receiving surfaces Is the second volume change chamber, and the operating state switching device is (a) a first accumulator connected to the first volume change chamber via a first liquid passage; (b) a first electromagnetic valve provided in the first liquid passage; and (c) the second volume. A second accumulator connected to the change chamber via a second liquid passage; (d) a second electromagnetic valve provided in the second liquid passage; (d) the first electromagnetic valve and the second electromagnetic valve; And a solenoid valve control unit that can be switched between a state in which the volume change in the first volume change chamber and a volume change in the second volume change chamber are allowed and a state in which the volume change is blocked by The suspension system according to (1) (claim 4).
(6) The suspension control device includes: (a) a front roll control solenoid valve provided in a communication path connecting the hydraulic cylinder of the left front wheel and the hydraulic cylinder of the right front wheel; and (b) the left front wheel A left-side pitch control solenoid valve provided in a communication path connecting the hydraulic cylinder of the left and the rear left hydraulic cylinder, and (c) the left rear hydraulic cylinder and the right rear hydraulic cylinder A rear-side roll control solenoid valve provided in the communication path connecting the right side wheel, and (d) a right-side pitch control provided in the communication path connecting the right rear wheel hydraulic cylinder and the right front wheel hydraulic cylinder. And (e) controlling the flow state of the hydraulic fluid between the two hydraulic cylinders on both sides of the solenoid valve by controlling each of the solenoid valves, thereby controlling the roll and pitch of the vehicle. A state that allows at least one of and (1) to claim and a solenoid valve control unit capable of switching the on purpose (5) suspension system according to any one of claim (Claim 5).
Rolls, pitches, and articulations are allowed when the left and right, front and rear hydraulic cylinders are in communication with each other, and rolls, pitches, and articulations are allowed when the left and right, front and rear hydraulic cylinders are blocked. Is suppressed. If the flow of hydraulic fluid between the left and right hydraulic cylinders is suppressed, the roll is suppressed, and if the flow of hydraulic fluid between the front and rear hydraulic cylinders is suppressed, the pitch is suppressed.
The suspension system includes a first diagonal passage that connects the hydraulic cylinder for the right front wheel and the hydraulic cylinder for the left rear wheel, and a first diagonal passage that connects the hydraulic cylinder for the left front wheel and the hydraulic cylinder for the right rear wheel. The suspension control device may include an electromagnetic valve provided in each of the first diagonal passage and the second diagonal passage, and an electromagnetic valve control unit that controls the electromagnetic valve. . If the flow of hydraulic fluid between them is allowed by the solenoid valves provided in the first and second diagonal passages, the roll and the pitch are allowed, and if the flow of hydraulic fluid between them is suppressed , Roll and pitch are suppressed.
(7) When the suspension control device suppresses the roll and pitch of the vehicle and allows articulation, the flow of hydraulic fluid in the right and left hydraulic cylinders on the right and left sides is controlled by the electromagnetic valve. The suspension system according to item (6) , including a hydraulic fluid suppression device that suppresses and suppresses the flow of hydraulic fluid in the left and right hydraulic cylinders on the front and rear sides.
As in the suspension system described in (6), a communication path for connecting four hydraulic cylinders is provided and an electromagnetic valve is provided. Even if the electromagnetic valve is controlled, the roll and pitch are suppressed and articulation is performed. An acceptable state cannot be realized. On the other hand, according to the articulation control device, it is possible to switch between a state where the articulation is allowed and a state where the articulation is suppressed in a state where the roll and pitch are suppressed. If the flow of hydraulic fluid between the front and rear hydraulic cylinders and between the left and right hydraulic cylinders is suppressed, the roll and pitch can be suppressed.
(8) The suspension control device includes a heave control device provided between the first operating device and the second operating device, and the heave control device includes: (i) a housing and a liquid-tight seal in the housing. And a third movable member that is a slidable stepped piston, and the hydraulic pressure of the first operating device acts on one of the two pressure receiving surfaces provided in the same direction of the third movable member, On the other hand, in a state where the hydraulic pressure of the second operating device acts, the first operating device, the third operating device to which the second operating device is connected, and (ii) allowing the movement of the third movable member, respectively. A movement permission / suppression device that can be switched between a state that allows heaves and a state that suppresses heaves by switching between a state and a suppression state, according to any one of items (1) to (7) Suspension system (Claim 6).
The third movable member is movable when the hydraulic pressure in the first volume change chamber and the hydraulic pressure in the second volume change chamber change in the same direction. In principle, the third actuator operates regardless of whether the flow of the hydraulic fluid is suppressed or allowed between the first volume change chamber and the second volume change chamber.
The heave control device may include an elastic force applying device that applies an elastic force from the opposite side of the two movable pressure receiving surfaces of the third movable member. The elastic force applying device may include a spring or an accumulator.
If the movement of the third movable member is allowed, heave is allowed, and if the movement is suppressed, the heave is suppressed.
(9) The suspension control device includes an articulation suppression / acceptance acquisition unit that acquires whether the articulation is to be suppressed or allowed to be suppressed (1) to (8) The suspension system according to any one of the above.
When articulation suppression / allowance acquisition unit determines that articulation should be suppressed, and when articulation is determined to be suppressed, and when articulation should be permitted In addition, articulation is allowed.
Whether the articulation should be permitted or suppressed can be acquired based on the traveling state of the vehicle or can be acquired based on the road surface state.
For example, when the longitudinal acceleration is greater than or equal to a set value during a turn, the degree of turn is greater than or equal to a set level (for example, when the turn radius is less than or equal to a set value, centrifugal force or lateral acceleration is greater than or equal to a set value, etc. It can be said that the articulation should be suppressed when the longitudinal acceleration is equal to or greater than the set value. Further, when the road surface has a large unevenness, or when the road surface is rough, such as when the unevenness frequency is high, the articulation should be allowed. The unevenness state of the road surface is acquired based on the detection value by the road surface state sensor, or based on the change amount, change speed, change acceleration (vertical acceleration), etc. of the relative distance between the wheel side member and the vehicle body side member. Or get it.
(10) The first actuator includes a first volume change chamber whose volume changes in accordance with the movement of the first movable member, and the second actuator has a volume in accordance with the movement of the second movable member. And the operation state switching device includes: a volume change according to the movement of the first movable member in the first volume chamber; and a second volume change chamber of the second volume change chamber. The suspension system according to item (2), including means for switching between a state where the volume change according to the movement is allowed and a state where the volume change is blocked.
If the volume change of the first volume change chamber and the second volume change chamber is allowed, the movement of the first movable member and the second movable member is allowed and the articulation is allowed. If the volume change between the first volume change chamber and the second volume change chamber is blocked, the movement of the first movable member and the second movable member is blocked and the articulation is suppressed.

BEST MODE FOR CARRYING OUT THE INVENTION

A suspension system according to an embodiment of the present invention will be described in detail with reference to the drawings.
In FIG. 1, hydraulic cylinders 10 to 16 are provided between the vehicle body side member 6 and the wheel side member 8 corresponding to the front, rear, left, and right wheels of the vehicle. Each of the hydraulic cylinders 10 to 16 includes a housing 20 and a piston 22 fitted in the housing 20 so as to be fluid-tight and slidable. In the present embodiment, the housing 20 is attached to the wheel side member 8 so as not to be relatively movable in the vertical direction and to be relatively rotatable, and the piston rod 24 of the piston 22 is not relatively movable in the vertical direction to the vehicle body side member 6 and is relatively rotatable. Mounted movably. The piston 22 is provided with a liquid passage 26 extending in the vertical direction. The two fluid chambers partitioned by the piston 22 are communicated with each other by the communication passage 26 and have the same fluid pressure. The hydraulic pressure in the hydraulic chamber 28 has a magnitude corresponding to the load acting between the wheel side member 8 and the vehicle body side member 6. An accumulator 30 is connected to the hydraulic pressure chamber 28 and relative movement of the piston 22 with respect to the housing 20 is allowed.

The fluid pressure chamber 28 of the fluid pressure cylinder 10 corresponding to the left front wheel and the fluid pressure chamber 28 of the fluid pressure cylinder 12 corresponding to the right front wheel are connected by a fluid passage 40 and the fluid of the fluid pressure cylinder 14 corresponding to the left rear wheel. The pressure chamber 28 and the hydraulic chamber 28 of the hydraulic cylinder 16 corresponding to the right rear wheel are connected by a fluid passage 42. The hydraulic cylinders 10 and 14 corresponding to the left front and rear wheels are connected by a fluid passage 44, and the hydraulic cylinders 12 and 16 corresponding to the right front and rear wheels are connected by a fluid passage 46. Solenoid valves 50 to 56 are provided in the liquid passages 40 to 46, respectively. The electromagnetic valves 50 to 56 are electromagnetic on-off valves that can be switched between an open state and a closed state by turning the solenoid ON / OFF.
In the present embodiment, the left and right hydraulic cylinders 10 to 16 are in communication with each other through liquid passages 40 to 46 as communication passages. In the open state of the solenoid valves 50 to 56, the flow of hydraulic fluid between the two hydraulic cylinders is allowed, and in the closed state, the flow of hydraulic fluid is blocked.

For example, when a roll having a direction in which the relative distance between the wheel side member 8 and the vehicle body side member 6 becomes smaller on the right side of the vehicle on the right side of the vehicle, the liquid in the hydraulic chamber 28 of the hydraulic cylinders 12, 16 is generated. The pressure becomes higher than the hydraulic pressure in the hydraulic chamber 28 of the hydraulic cylinders 10 and 14.
When the solenoid valves 50 and 52 are in the open state, the hydraulic fluid flows from the hydraulic cylinders 12 and 16 toward the hydraulic cylinders 10 and 14. In each of the hydraulic cylinders 10 to 16, relative movement of the piston 22 with respect to the housing 20 is allowed, and relative movement between the wheel side member 8 and the vehicle body side member 6 due to the roll is allowed.
When the solenoid valves 50 and 52 are in the closed state, the flow of hydraulic fluid between the left and right hydraulic cylinders 10 and 12 and between the left and right hydraulic cylinders 14 and 16 is blocked. The hydraulic cylinders 10 to 16 are the same as being made independent, and the relative movement of the piston 22 with respect to the housing 20 in the hydraulic cylinders 10 to 16 is larger than when the solenoid valves 50 and 52 are open. The relative movement between the wheel side member 8 and the vehicle body side member 6 due to the roll is suppressed.
Thus, by switching the electromagnetic valves 50 and 52 between the open state and the closed state, it is possible to switch between a state where the roll is allowed and a state where the roll is suppressed.

For example, when a pitch occurs in which the relative distance between the wheel side member 8 and the vehicle body side member 6 becomes smaller on the front side of the vehicle than on the rear side, the hydraulic pressure of the hydraulic cylinders 10 and 12 increases. The hydraulic pressure in the pressure cylinders 14 and 16 is reduced.
When the solenoid valves 54 and 56 are in the open state, the flow of hydraulic fluid from the front-wheel hydraulic cylinders 10 and 12 to the rear-wheel hydraulic cylinders 14 and 16 is allowed, and the pitch is allowed.
When the solenoid valves 54 and 56 are in the closed state, the flow of the hydraulic fluid is blocked, so that the hydraulic cylinders 10 to 16 are the same as when the solenoid valves 54 and 56 are opened independently. The pitch is suppressed compared to the case of
As described above, the opening and closing of the electromagnetic valves 54 and 56 can be switched between a state in which the pitch is suppressed and a state in which the pitch is allowed.
A roll / pitch control device 58 is constituted by the liquid passages 40 to 46, the electromagnetic valves 50 to 56, and the like. The electromagnetic valves 50 and 52 can be referred to as roll suppression control valves, and the electromagnetic valves 54 and 56 can be referred to as pitch suppression control valves.

Individual hydraulic passages 60 to 66 are connected to the left and right hydraulic cylinders 10 to 16, respectively, and an articulation control device 70 is provided in each of the individual passages 60 to 66.
The articulation control device 70 includes a first hydraulic cylinder 80 as a first operating device, a second hydraulic cylinder 82 as a second operating device, and an electromagnetic valve 84 provided therebetween. The first and second hydraulic cylinders 80 and 82 include housings 90 and 91 each having a cylinder bore having a stepped shape, and stepped pistons fitted to the housings 90 and 91 in a liquid-tight and slidable manner, respectively. And first and second movable members 92 and 93. The end surfaces of the first and second movable members 92 and 93 with the small diameter portions are the first pressure receiving surfaces 94 and 95, and the end surfaces of the step portions of the small diameter portion and the large diameter portion are the second pressure receiving surfaces 96 and 97, respectively. The end surfaces of the diameter portions are the third pressure receiving surfaces 98 and 99, and the liquid chambers facing the third pressure receiving surfaces 98 and 99 are the volume change chambers 100 and 101. The first pressure receiving surfaces 94 and 95 and the second pressure receiving surfaces 96 and 97 are provided on the same side of each of the first and second movable members 92 and 93, and the first pressure receiving surfaces 94 and 95 and the second pressure receiving surfaces 96 and 97 are provided. The third pressure receiving surfaces 98 and 99 are provided so as to face each other.

The first hydraulic cylinder 80 includes a fluid passage 60 connected to the hydraulic cylinder 10 for the left front wheel and a fluid passage 66 connected to the hydraulic cylinder 16 for the right rear wheel. The hydraulic pressure of the hydraulic cylinder 10 for the left front wheel acts on the surface 94, and the second pressure receiving surface 96 is connected in a state where the hydraulic pressure of the hydraulic cylinder 16 for the right rear wheel acts. The second hydraulic cylinder 82 includes a fluid passage 62 connected to the hydraulic cylinder 12 on the right front wheel and a fluid passage 64 connected to the hydraulic cylinder 14 on the left rear wheel. The hydraulic pressure of the right front wheel hydraulic cylinder 12 acts on the surface 95 and the second pressure receiving surface 97 is connected in a state where the hydraulic pressure of the left rear wheel hydraulic cylinder 14 acts.
Further, the volume change chamber 100 of the first hydraulic cylinder 80 and the volume change chamber 101 of the second hydraulic cylinder 82 are connected by a communication path 102, and an electromagnetic valve 84 is provided in the communication path 102. The electromagnetic valve 84 is an electromagnetic open / close valve that can be switched between an open state and a closed state by turning ON / OFF the current supplied to the solenoid. By opening / closing the electromagnetic valve 84, the flow of the hydraulic fluid between the volume change chambers 100, 101 is switched between a permitted state and a blocked state. A state in which the volume change of the volume change chambers 100 and 101 is allowed and the movement of the movable members 92 and 93 is allowed, and a volume change of the volume change chambers 100 and 101 is blocked and the movement of the movable members 92 and 93 is blocked. It can be switched to the state.

For example, the relative distance between the vehicle body side member 6 and the wheel side member 8 is reduced at the left front wheel and the right rear wheel, and the relative distance between the vehicle body side member 6 and the wheel side member 8 is increased at the right front wheel and the left rear wheel. When curation occurs, the hydraulic pressures of the hydraulic cylinders 10 and 16 for the left front wheel and the right rear wheel increase, and the hydraulic pressures of the hydraulic cylinders 12 and 14 for the right front wheel and the left rear wheel decrease.
In the first hydraulic cylinder 80, the hydraulic pressure of the first pressure receiving surface 94 and the second pressure receiving surface 96 of the first movable member 92 is increased, and the hydraulic pressure of the volume change chamber 100 is increased. In the second hydraulic cylinder 82, the hydraulic pressures of the first pressure receiving surface 95 and the second pressure receiving surface 97 of the second movable member 93 are reduced, and the hydraulic pressure of the volume change chamber 101 is reduced.

In this case, when the electromagnetic valve 84 is in the open state, the hydraulic fluid flows from the first hydraulic cylinder 80 toward the second hydraulic cylinder 82. In the first hydraulic cylinder 80 and the second hydraulic cylinder 82, the volume change of the first volume change chamber 100 and the second volume change chamber 101 is allowed, and the movement of the first movable member 92 and the second movable member 93 is allowed. Is done. Thereby, relative movement of the piston 22 with respect to the housing 20 in the hydraulic cylinders 10 to 16 is allowed, and relative movement with respect to the wheel side member 8 and the vehicle body side member 6 is allowed. Articulation is allowed.
When the solenoid valve 84 is in the closed state, the flow of hydraulic fluid between the first hydraulic cylinder 80 and the second hydraulic cylinder 82 is blocked. In both the first hydraulic cylinder 80 and the second hydraulic cylinder 82, the movement of the first movable member 92 and the second movable member 93 is suppressed. Thereby, articulation is suppressed.

A heave controller 108 is provided between the first hydraulic cylinder 80 and the second hydraulic cylinder 82 in parallel with the electromagnetic valve 84.
The heave suppressing device 108 includes a third hydraulic cylinder 110 and an accumulator 111. The third hydraulic cylinder 110 includes a housing 112 and a third movable member 114 that is a stepped piston that is fluid-tightly and slidably fitted to the housing 112. The first pressure receiving surface 120, which is the end surface on the small diameter side of the third movable member 114, receives the hydraulic pressure in the volume change chamber 101 of the second hydraulic cylinder 82, and is the end surface of the step portion of the small diameter portion and the large diameter portion. A certain second pressure receiving surface 122 receives the hydraulic pressure of the volume change chamber 100 of the second hydraulic cylinder 80. An accumulator 111 is connected to the volume change chamber 126 facing the end surface 124 on the large-diameter portion side via an electromagnetic valve 130. The electromagnetic valve 130 is a normally closed electromagnetic on-off valve that can be switched between an open state and a closed state by ON / OFF of a supply current to the solenoid. The third movable member 114 is movable when the hydraulic pressures of the volume change chambers 100 and 101 change in the same direction, that is, when the hydraulic pressures of the hydraulic cylinders 10 to 16 all change in the same direction. is there.

In the open state of the solenoid valve 130, the flow of the hydraulic fluid between the volume change chamber 126 and the accumulator 111 is allowed, the movement of the third movable member 114 is allowed, and the heave is allowed. In the closed state of the electromagnetic valve 130, the flow of the hydraulic fluid between the volume change chamber 126 and the accumulator 111 is suppressed, the movement of the third movable member 114 is suppressed, and the heave is suppressed.
When heave occurs, the liquid in the volume change chambers 100 and 101 of the first hydraulic cylinder 80 and the second hydraulic cylinder 82 is maintained regardless of whether the electromagnetic valve 84 is open or closed. Since the pressures are almost the same, the hydraulic fluid does not flow through the electromagnetic valve 84, and the third hydraulic cylinder 110 is operated.

This suspension system is controlled based on a command from the suspension ECU 200. The suspension ECU 200 is mainly a computer and includes an execution unit 202, a storage unit 204, an input / output unit 206, and the like. The input / output unit 206 is connected to a traveling state detection device 210 that detects the traveling state of the vehicle. The traveling state detection device 210 includes a turning state detection device 212 that detects a turning state, a front / rear G sensor 214 that detects front / rear acceleration, and the like. The turning state detection device 212 can include a lateral acceleration sensor, a steering angle sensor and a vehicle speed sensor, or a yaw rate sensor.
In the present embodiment, when the lateral acceleration is greater than or equal to the set value, when the centrifugal force is greater than or equal to the set value, or when the yaw rate is greater than or equal to the set value, the turning level is greater than or equal to the set level. Solenoids of the solenoid valves 50 to 56, 84, and 130 are connected to the execution unit 202 via a drive circuit (not shown). The storage unit 204 stores an attitude change control program represented by the flowchart of FIG.

In the present embodiment, the solenoid valves 50 to 56 and 84 are normally open valves, and the solenoid valve 130 is a normally closed valve. When no current is supplied to each solenoid, it is in the position shown in the figure. In this state, roll, pitch, and articulation are allowed and heave is suppressed.
The posture change control program represented by the flowchart of FIG. 2 is executed at predetermined time intervals. In step 1 (hereinafter abbreviated as S1, the same applies to other steps), it is determined whether or not the turning level is equal to or higher than the set level.
If the turning level is greater than or equal to the set level, it is determined in S2 whether the longitudinal acceleration is greater than or equal to the set acceleration. If the longitudinal acceleration is smaller than the set acceleration, the electromagnetic valves 50 and 52 are closed and the electromagnetic valve 84 is opened in S3 and S4. In this case, the roll of the vehicle is suppressed and the pitch is allowed.
If the turning level is lower than the set level, it is determined in S5 whether or not the absolute value of the longitudinal acceleration is greater than or equal to the set value. If the absolute value of the longitudinal acceleration is greater than or equal to the set value, the solenoid valves 54 and 56 are closed and the solenoid valve 84 is opened in S6 and S7. In this case, the pitch is suppressed and the roll is allowed.
In these cases, articulation is allowed because the electromagnetic valve 84 is in the open state. Thereby, it is possible to suppress a decrease in riding comfort due to road surface input. Moreover, since any one of the solenoid valve 50 and the solenoid valve 52 and the solenoid valve 54 and the solenoid valve 56 is in the open state, the articulation is allowed by this.

When the turning level is equal to or higher than the set level and the longitudinal acceleration is equal to or higher than the set acceleration, the solenoid valves 50 to 56 are closed and the solenoid valve 84 is closed in S8 and S9. . Roll and pitch are suppressed, and articulation is suppressed. Thereby, running stability when turning at a large acceleration can be improved.
When the turning level is lower than the set level and the absolute value of the longitudinal acceleration is also smaller than the set value, no current is supplied to the solenoid valves 50 to 56 and the solenoid valve 84, and the position shown in the figure is obtained. Thereby, roll, pitch and articulation are allowed.

Thus, according to this embodiment, when the turning state is higher than the set level and the longitudinal acceleration is equal to or greater than the set value, the roll and pitch are suppressed and the articulation is suppressed. Thereby, running stability can be improved.
In other cases, since articulation is allowed, for example, traveling stability can be ensured, and a decrease in riding comfort due to road surface input can be suppressed.
As described above, in the present embodiment, the solenoid valves 50 to 56, 84, the first hydraulic cylinder 80, the second hydraulic cylinder 82, and the posture change control program represented by the flowchart of FIG. The suspension control device is constituted by the portion to be executed, the portion to be executed, and the like, and the operation state switching device is constituted by the portion for storing S4, 7, 9 and the portion to be executed among them. The first hydraulic cylinder 80, the second hydraulic cylinder 82, etc. constitute an operating device.

  In the above embodiment, the solenoid valves 50 and 52 are closed in S3 and the solenoid valves 54 and 56 are closed in S6. However, the solenoid valves 50 to 56 are closed. You can also. The flowchart of the posture change suppression program in that case is shown in FIG. In the present embodiment, the solenoid valves 50 to 56 are closed in S3 ′ and 6 ′. If the turning state is equal to or higher than the set level and the absolute value of the longitudinal acceleration is equal to or higher than the set value, the traveling stability can be improved by closing all the solenoid valves 50 to 56.

The structure of the articulation control device is not limited to that in the above embodiment.
For example, the articulation control device 248 shown in FIG. 4 includes the same first and second hydraulic cylinders 80 and 82 as in the above embodiment, but the volume of the first and second hydraulic cylinders 80 and 82 is the same. Accumulators 254 and 256 are connected to the change chambers 100 and 101 via liquid passages 250 and 252, respectively. The liquid passages 250 and 252 are provided with electromagnetic valves 260 and 262, respectively.
In the open state of the electromagnetic valves 260 and 262, the volume change chambers 100 and 101 and the accumulators 254 and 256 are communicated with each other. Volume changes in the volume change chambers 100 and 101 are allowed, and movement of the first and second movable members 92 and 93 is allowed. Thereby, articulation is allowed.
When the electromagnetic valves 260 and 262 are closed, the volume change chambers 100 and 101 and the accumulators 254 and 256 are blocked, and the movement of the first and second movable members 92 and 93 is suppressed. Thereby, articulation is suppressed.
In addition, heave is also permitted in the open state of the electromagnetic valves 260 and 262.

  5 includes a first hydraulic cylinder 302 and a second hydraulic cylinder 304. The articulation permission apparatus 300 shown in FIG. In the first hydraulic cylinder 302 and the second hydraulic cylinder 304, the first and second pistons 314 and 316 are fitted into the housings 310 and 312 so as to be fluid-tight and slidable, respectively. The two first and second pistons 314 and 316 are connected by a connecting rod 318. The first and second pistons 314 and 316 and the connecting rod 318 are integrally movable, and this is referred to as a control piston 320.

The first hydraulic cylinder 302 is provided between the left front wheel hydraulic cylinder 10 and the left rear wheel hydraulic cylinder 14, and the second hydraulic cylinder 304 includes the right front wheel hydraulic cylinder 12 and the right rear wheel. Provided between the hydraulic cylinders 16.
In the first hydraulic cylinder 302, the first pressure receiving surface 320 outside the first piston 314 receives the hydraulic pressure of the hydraulic cylinder 10 of the left front wheel, and the inner second pressure receiving surface 322 receives the hydraulic pressure of the left rear wheel. The hydraulic pressure of the cylinder 14 is received. In the second hydraulic cylinder 304, the third pressure receiving surface 324 inside the second piston 316 receives the hydraulic pressure of the hydraulic cylinder 16 of the right rear wheel, and the outer fourth pressure receiving surface 326 receives the hydraulic pressure of the right front wheel. The hydraulic pressure of the cylinder 12 is received.
In the control piston 320, the hydraulic pressure of the hydraulic cylinder 10 for the left front wheel and the hydraulic pressure of the hydraulic cylinder 16 for the right rear wheel are in the same direction, and the hydraulic pressure of the hydraulic cylinder 12 for the right front wheel and the hydraulic pressure of the left rear wheel. The hydraulic pressure of the cylinder 14 is in the same direction, and these act in opposite directions.

  The control piston 320 is provided with a moving state control device 330. The movement state control device 300 includes a fourth hydraulic cylinder 332. The fourth hydraulic cylinder 332 includes a housing 334 and a piston 336 that is provided on the connecting rod 318 so as not to move relatively. The connecting rod 318 is provided by protruding the pistons 314 and 316, and the piston 336 is provided at the protruding portion. The interior of the housing 334 is divided into two hydraulic chambers 338 and 339 by a piston 336. The two hydraulic chambers 338 and 339 are connected by a liquid passage 340, and an electromagnetic valve 342 is provided in the liquid passage 340. The electromagnetic valve 342 is an electromagnetic open / close valve that is opened and closed by turning on and off the current supplied to the solenoid.

When articulation occurs, the hydraulic pressure of one of the hydraulic cylinders of the left front wheel and right rear wheel and the hydraulic cylinder of the right front wheel and left rear wheel increases, and the other hydraulic pressure increases. Lower. In the control piston 320, the state of balance changes, and a hydraulic pressure difference is generated between the hydraulic chambers 338 and 339 in the fourth hydraulic cylinder 332.
When the electromagnetic valve 342 is in the open state, the flow of hydraulic fluid from the higher hydraulic pressure chamber to the lower hydraulic pressure chamber is allowed between the hydraulic pressure chambers 338 and 339, and the control piston 320 movements are allowed and articulations are allowed.
When the electromagnetic valve 342 is in the closed state, the flow of hydraulic fluid between the hydraulic chambers 338 and 339 is blocked, and the movement of the control piston 320 is blocked. Thereby, articulation is suppressed.
As described above, in this embodiment, by switching the electromagnetic valve 342 between the open state and the closed state, it is possible to switch between the state where articulation is allowed and the state where it is suppressed.

  The articulation control device 300 is provided with an elastic force applying device that applies an elastic force according to the movement of the control piston 320 and a damping force generator that generates a damping force according to the moving speed of the control piston 320. Can do. As the elastic force applying device, it is desirable to employ a spring.

Moreover, in the said embodiment, although the hydraulic cylinders 10-16 provided for each of the left and right and front and rear wheels are single-acting, they can be shock absorbers. When two or more shock absorbers are communicated with each other, the damping force is small, and when the shock absorbers are independent, the damping force is large and the change in posture is suppressed. become.
Furthermore, in the above embodiment, when the turning level is equal to or higher than the set level and the longitudinal acceleration is equal to or higher than the set value, the articulation is suppressed. Even if it is above or lower than the set level, when the vehicle is turning, if the longitudinal acceleration is equal to or higher than the set value, the articulation can be suppressed.
In the above-described embodiment, the four hydraulic cylinders 10 to 16 are in communication with each other by the liquid passages 40 to 46. However, it is not indispensable to have communication with each other. For example, a communication path that connects the hydraulic cylinder 10 for the left front wheel and the hydraulic cylinder 16 for the right rear wheel, and a communication path that connects the hydraulic cylinder 12 for the right front wheel and the hydraulic cylinder 14 for the left rear wheel. It is possible to provide electromagnetic valves in these communication paths.

Furthermore, it is not essential to be able to switch between a state where articulation is allowed and a state where articulation is suppressed. The electromagnetic valve 84 is not indispensable. If the volume change chambers 100 and 101 of the first and second hydraulic cylinders 80 and 82 are in communication with each other, the roll and pitch are suppressed when the electromagnetic valves 50 to 56 are closed. Thus, articulation is allowed.
In addition, the solenoid valves 50 to 56, 84, and 130 can be flow path control valves whose flow path areas can be continuously changed in an open state, rather than electromagnetic open / close valves.
In addition to the aspects described in the above [Problems to be Solved by the Invention, Problem Solving Means and Effects], the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art. it can.

1 is a diagram conceptually showing an entire suspension system according to an embodiment of the present invention. It is a flowchart showing the attitude | position change suppression program memorize | stored in the memory | storage part of suspension ECU of the said suspension system. It is a flowchart showing another attitude | position change suppression program memorize | stored in the memory | storage part of suspension ECU of the said suspension system. It is a figure which shows another aspect of a part of said suspension system. It is a figure which shows another aspect of a part of said suspension system.

Explanation of symbols

10-16: Hydraulic cylinder 40-46: Liquid passage 50-56: Electromagnetic valve 60-66: Connection passage 70: Articulation control device 80, 82: Hydraulic cylinder 84: Electromagnetic valve 248: Articulation control device 260, 262: Solenoid valve 300: Articulation control device 320: Control piston 330: Movement control device 342: Solenoid valve

Claims (6)

  A suspension system provided between the front and rear wheels and the vehicle body of the vehicle,
  Hydraulic cylinders respectively provided corresponding to the front, rear, left and right wheels;
  (a) The first movable member that is movable when the hydraulic pressure of the right front wheel hydraulic cylinder and the hydraulic pressure of the left rear wheel hydraulic cylinder change in the same direction among the front, rear, left and right hydraulic cylinders. And (b) the first movable member movable when the hydraulic pressure of the hydraulic cylinder of the left front wheel and the hydraulic cylinder of the right rear wheel change in the same direction. And a second actuating device having a second movable member that is separate from the first movable member and permitting movement of the first movable member and the second movable member in a state where the roll and pitch of the vehicle are suppressed. By switching between the state and the state in which the movement of the first movable member and the second movable member is prevented, the wheels in the diagonal position among the front, rear, left and right wheels are in phase in the vertical direction, and , Two belonging to one of the two sets of wheels that are diagonal to each other Two and is a state that allows the movement in the opposite phase and the suspension controller capable of switching on and the inhibit movement state wheels belonging to wheels and other
A suspension system comprising:   The suspension control device controls and prevents the movement of the first and second movable members by controlling the state of hydraulic fluid exchange between the first operating device and the second operating device. The suspension system according to claim 1, further comprising an operation state switching device capable of switching to a state to be performed.   The first movable member is a stepped piston that is liquid-tightly and slidably fitted to a housing. In the first operating device, two pressure receiving surfaces provided in the same direction of the first movable member are provided. The left front wheel hydraulic cylinder and the right rear wheel hydraulic cylinder are connected in a state in which the hydraulic pressure is applied, and the liquid chamber facing the remaining pressure receiving surface is a first volume change chamber. The second movable member is a stepped piston that is liquid-tightly and slidably fitted to the housing. In the second operating device, the two movable members are provided in the same direction of the second movable member. The hydraulic cylinder for the right front wheel and the hydraulic cylinder for the left rear wheel are connected to the pressure receiving surface in a state in which the hydraulic pressure acts, and a liquid chamber facing the remaining pressure receiving surface is second. A volume change chamber, and the operating state switching device is (a) An electromagnetic valve provided in a liquid passage connecting the first volume change chamber and the second volume change chamber; and (b) an operation between them by controlling a supply current to the solenoid of the electromagnetic valve. The suspension system according to claim 2, further comprising a flow state control device that switches between a state in which liquid flow is allowed and a state in which liquid flow is blocked.   The first movable member is a stepped piston that is liquid-tightly and slidably fitted to a housing. In the first operating device, two pressure receiving surfaces provided in the same direction of the first movable member are provided. The left front wheel hydraulic cylinder and the right rear wheel hydraulic cylinder are connected in a state in which the hydraulic pressure is applied, and the liquid chamber facing the remaining pressure receiving surface is a first volume change chamber. The second movable member is a stepped piston that is liquid-tightly and slidably fitted to the housing. In the second operating device, the two movable members are provided in the same direction of the second movable member. The hydraulic cylinder for the right front wheel and the hydraulic cylinder for the left rear wheel are connected to the pressure receiving surface in a state in which the hydraulic pressure acts, and a liquid chamber facing the remaining pressure receiving surface is second. A volume change chamber, and the operating state switching device is (a) A first accumulator connected to the first volume change chamber via a first liquid passage; (b) a first electromagnetic valve provided in the first liquid passage; and (c) a second volume change chamber. A second accumulator connected via a second liquid passage; (d) a second electromagnetic valve provided in the second liquid passage; (d) the first electromagnetic valve and the second electromagnetic valve; The electromagnetic valve control part which can be switched to the state which accept | permits the volume change of the said 1st volume change chamber and the volume change of the said 2nd volume change chamber by each controlling, and the state which blocks | prevents. Suspension system described in.   The suspension control device comprises: (a) a front roll control solenoid valve provided in a communication path connecting the hydraulic cylinder of the left front wheel and the hydraulic cylinder of the right front wheel; and (b) the hydraulic pressure of the left front wheel. A solenoid valve for left pitch control provided in a communication path connecting the cylinder and the hydraulic cylinder for the left rear wheel; and (c) connecting the hydraulic cylinder for the left rear wheel and the hydraulic cylinder for the right rear wheel. A rear roll control solenoid valve provided in the communication path; and (d) a right pitch control solenoid valve provided in the communication path connecting the hydraulic cylinder of the right rear wheel and the hydraulic cylinder of the right front wheel. And (e) controlling each of the solenoid valves to control the flow state of the hydraulic fluid between the two hydraulic cylinders on both sides of the solenoid valves, thereby providing at least the roll and pitch of the vehicle. A state that allows one and a state that suppresses at least one The suspension system according to any one of claims 1 to 4 and a solenoid valve control unit capable of switching to.   The suspension control device includes a heave control device provided between the first operating device and the second operating device, and the heave control device includes: (i) a housing, and a fluid-tight and sliding slide on the housing A third movable member that is a stepped piston, and the hydraulic pressure of the first operating device acts on one of two pressure receiving surfaces provided in the same direction of the third movable member, and the other A third operating device to which the first operating device and the second operating device are connected, respectively, in a state in which the hydraulic pressure of the second operating device acts, and (ii) a state in which the movement of the third movable member is allowed and a suppression The suspension system according to any one of claims 1 to 5, further comprising a movement permission / suppression device that can be switched between a state that allows heaves and a state that suppresses heaves.

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