JP2008168747A - Articulation acceptable suspension system - Google Patents

Abstract

In a suspension system capable of suppressing rolling and allowing articulation, jacking up of a vehicle body is facilitated.
When the vehicle height control is not performed (S2) and the vehicle is stopped (S4), a jack-up switch that should be manually operated before the start of jack-up is turned ON ( In S6), the valve in the articulation suppression state is closed (S12). Alternatively, the change in vehicle height corresponding to one of the four wheels exceeds a threshold value set to a small value (L1) when the door is closed and a large value (L2) when the door is open. In this case, it is determined that jackup has been started (S10), and the valve to be in the articulation suppression state is closed (S12). The valve once closed is opened when the end of jackup is detected (S13), and returned to the articulation allowable state (S16).
[Selection] Figure 4

Description

  The present invention relates to a vehicle suspension system, and more particularly to a suspension system capable of both suppressing rolling and allowing articulation.

This type of suspension system is already known, for example, from Patent Document 1 below. When the vehicle turns, a roll moment is generated. The roll moment is a moment that rotates the vehicle body about an axis extending substantially in the front-rear direction. Rolling of the vehicle body due to the roll moment reduces the ride comfort and running stability of the vehicle, and is therefore desired to be suppressed. In order to suppress rolling, it is necessary to suppress the relative movement of the wheel and the vehicle body in the vertical direction. On the other hand, when the vehicle travels on a road surface with relatively large unevenness (hereinafter abbreviated as a bad road). Therefore, it is desirable to allow the relative movement between the wheel and the vehicle body to suppress the shaking of the vehicle body, and for this purpose, a suspension excellent in the ability to allow articulation is required. Articulation is usually used as `` wheel articulation '' and is used as a term indicating the difficulty of lifting the wheel when driving on rough roads. Therefore, it is necessary to allow the relative movement directions of the left and right wheels with respect to the vehicle body to be opposite to each other. A vehicle having a higher permissible capacity is suitable for traveling on a rough road. Therefore, in this specification, the phenomenon itself in which the directions of relative movement of the left and right wheels with respect to the vehicle body are opposite to each other on the front side and the rear side of the vehicle is referred to as articulation. The suspension system described in the following Patent Document 1 is an example that can meet the requirements of both the suppression of the roll moment and the allowance of articulation.
WO2004 / 080735 JP 2004-17849 A

  Thus, a suspension system (referred to as an articulation allowable system) capable of both suppressing rolling and allowing articulation is excellent, but there is still room for improvement. For example, when jacking up the part corresponding to one of the front, rear, left and right wheels of the vehicle body to lift the wheel corresponding to that part from the road surface, the articulation permission function Since the wheel to be moved easily moves away from the vehicle body, the jack-up amount of the vehicle body must be increased as compared with a vehicle having a suspension system that is not an articulation allowable type. This problem is an example of a problem that hinders the practical use of the conventional suspension system, and the conventional system has room for improvement from various viewpoints. The present invention has been made in view of this situation, and an object of the present invention is to obtain a more practical suspension system.

  In order to solve the above-described problems, the present invention provides a suspension system capable of suppressing rolling while a vehicle is running and allowing articulation, and suppressing articulation during stopping to suppress articulation while stopping. A device is provided.

  Allowing articulation is beneficial while the vehicle is running, but it is often desirable not to allow it when the vehicle is stopped. The increase in the jack-up amount is an example. The present invention has been made in recognition of this fact.According to the present invention, the use of the articulation permission function during traveling and the avoidance of inconvenience due to the presence of the articulation function while stopped are avoided. It has succeeded in making it compatible easily.

  Patent Document 2 describes an invention that facilitates jack-up in a work vehicle having an outrigger. In this type of work vehicle, when the vehicle body is jacked up by the outrigger, the wheel easily falls off the vehicle body due to the presence of the suspension system, and the amount of jack-up required to separate the wheel from the road surface increases. In order to avoid this inconvenience, an invention is described in which the suspension system is locked so as not to operate when the outrigger is operated. However, this technology solves the problems peculiar to work vehicles equipped with outriggers based on the operating state of the outriggers, and can be applied as it is to ordinary vehicles such as passenger cars equipped with an articulation allowable suspension system. is not.

Aspects of the 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, the prior art, and the like. The added aspect and the aspect in which the constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

  In each of the following terms, (1) corresponds to claim 1, (2) corresponds to claim 2, (3) corresponds to claim 3, (4) corresponds to claim 4, (7) corresponds to claim 5, (9) corresponds to claim 6, (10) corresponds to claim 7, and (12) corresponds to claim 8.

(1) In a suspension system that can take a state of suppressing articulation while suppressing rolling while the vehicle is running,
A suspension system comprising an articulation suppression device that stops articulation while the vehicle is stopped.
The articulation suppressing device may be configured to always suppress articulation while the vehicle is stopped, or to suppress when the vehicle is stopped and a specific condition is satisfied. In the former case, the stopping articulation suppression device is a drive source state-based stop detection device that detects that the main drive device such as an engine is stopped, or the transmission is in the neutral range. A device that detects a stop by itself, such as a transmission state-based stop detection device that detects that the vehicle is in a non-traveling range such as a parking range, or a wheel speed-based stop detection device that detects that the rotational speed of a wheel is below a set speed. Or a stop information receiving unit that receives information indicating that the vehicle is stopping from a stop detection device already provided for other purposes. These stop detection devices and stop information receiving units are collectively referred to as a stop state acquisition unit. In the latter case, when it is to be suppressed when the vehicle is stopped and a specific condition is satisfied, it is detected that the specific condition is satisfied in addition to the stop state acquisition unit, or It is desirable to include a specific condition establishment state acquisition unit that receives information to that effect, but the specific condition is established only when the vehicle is stopped, and it can be considered that the establishment of the specific condition also serves as a condition of stopping In addition, the stop state acquisition unit can be omitted.
(2) one or more front hydraulic actuators that are provided corresponding to the left and right front wheels provided on the left and right of the front side of the vehicle, and that operate in accordance with the relative movement of the left and right front wheels in the vertical direction;
One or more rear hydraulic actuators provided corresponding to the left and right rear wheels provided on the left and right of the rear side of the vehicle, and operating in accordance with the vertical movement of the left and right rear wheels relative to the vehicle body;
A liquid passage network including one or more liquid passages connecting the corresponding fluid chambers of the front hydraulic pressure actuator and the rear hydraulic pressure actuator;
Provided in the liquid passage network, the state of communication between the front hydraulic pressure actuator and the rear hydraulic pressure actuator via the liquid passage network is allowed to allow articulation and to suppress articulation. A switching valve device for switching to a suppressed state;
A valve device control device that controls switching of the switching valve device, and the valve device control device comprises:
A traveling control unit that switches the switching valve device between the permissible state and the restrained state at least at one time during travel of the vehicle;
A suspension control unit that switches the switching valve device to the suppressed state at least at one time during a stop of the vehicle.
When the articulation permission device includes the front hydraulic pressure actuator, the rear hydraulic pressure actuator, the liquid passage network, the switching valve device, and the valve device control device, the valve device control device is connected to the running control unit. And the stopping control unit, and the object of the invention of item (1) can be achieved at low cost.
The suspension control unit can be an “electrical control unit” including those described in (8), (10) to (12), which will be described later. This is desirable. However, it is possible to use a manually operated valve, and the purpose can be achieved particularly at a low cost. For example, the valve that is electrically controlled in the items (8), (10) to (12), etc. and realizes the articulation suppression state is changed to a manually operated valve, or other valve that is electrically controlled. A manually operated valve is added to the valve, or a manually operated part is added to an electrically controlled valve. In these aspects, the manual operation valve and the manual operation unit constitute a stop control unit.
Also in the traveling control unit, as described later in the section of the embodiment, the valve that is closed due to the occurrence of leakage of hydraulic fluid or the like can be a manually operated valve.
(3) The suspension system according to (2), wherein the traveling control unit includes a turning response control unit that keeps the switching valve device in an allowable state during straight traveling of the vehicle and switches to a suppressed state when the vehicle turns.
In general, in order to suppress rolling, it is better to place the articulation permission device in a suppressed state. When the articulation permission device includes the front hydraulic pressure actuator, the rear hydraulic pressure actuator, the liquid passage network, the switching valve device, and the valve device control device, the articulation control device does not have to be in an articulation suppression state during turning. Rolling can often be suppressed, but even in that case, rolling can be suppressed better in the articulation suppression state.
(4) a front stabilizer bar that is disposed with respect to the left and right front wheels and is rotatable relative to the vehicle body in a vertical plane parallel to a lateral direction of the vehicle;
A rear stabilizer bar disposed with respect to the left and right rear wheels and rotatable relative to the vehicle body in a vertical plane parallel to a lateral direction of the vehicle, the front hydraulic pressure actuator and the rear hydraulic pressure The actuator can change each of the front stabilizer bar and the rear stabilizer bar into a state in which relative rotation with respect to the vehicle body is suppressed and a state in which the actuator is allowed. Suspension system.
According to the suspension system including the stabilizer bar and the hydraulic actuator that changes the operation state thereof, it is possible to easily realize both the allowance of articulation and the suppression of the rolling.
(5) At least one of the front hydraulic pressure actuator and the rear hydraulic pressure actuator is located between at least one of the front stabilizer bar and the rear stabilizer bar and the vehicle body, and the side of the vehicle between the one and the vehicle body. The suspension system according to item (4), wherein the suspension system is a hydraulic cylinder that is arranged to expand and contract with relative rotation in a vertical plane parallel to the direction.
The articulation permission device in this section is a more specific example of the one in section (4). In the suspension system of this section, a switching circuit is provided for switching the front hydraulic pressure actuator and the rear hydraulic pressure actuator to a state in which the front hydraulic pressure actuator and the rear hydraulic pressure actuator can be freely expanded and contracted independently and a suppressed state in which expansion and contraction is suppressed (including a blocking state). In this case, a suspension system in which the rolling allowance and suppression and the articulation allowance and suppression correspond to each other can be obtained.
Further, as will be described later as an example, if two fluid passages for connecting the corresponding fluid pressure chambers of the front hydraulic pressure actuator and the rear hydraulic pressure actuator are provided, the rolling suppression state and the articulation are Can be realized at the same time. However, in this hydraulic circuit, if an electromagnetic on-off valve for controlling the communication and shut-off of the two liquid passages is provided and the electromagnetic on-off valve is in the shut-off state, rolling can be suppressed more reliably.
(6) a front stabilizer bar disposed between the left and right front wheels;
A rear stabilizer bar disposed between the left and right rear wheels, wherein at least one of the front stabilizer bar and the rear stabilizer bar is divided into a right side member and a left side member, the front hydraulic pressure actuator and the At least one of the rear hydraulic pressure actuator is provided between the right side member and the left side member, and is a rotary that rotates with the relative rotation of the right side member and the left side member about an axis extending in the left-right direction of the vehicle. The suspension system according to (2) or (3), which is an actuator.
The articulation permission device in this section is another example of the one in section (4). If the stabilizer bar is divided into a right side member and a left side member, a rotary actuator is provided between the two members, and the rotary actuator is allowed to rotate relative to the right side member and the left side member, the articulation allowable state is As a result, an articulation-suppressed state and a rolling-suppressed state can be obtained if the relative rotation is suppressed. For example, a stabilizer device including a rotary actuator described in JP-A-2004-122944 and left and right stabilizer bars is provided on the front wheel side and the rear wheel side, and two ports of each of these rotary actuators are connected by two liquid passages. A switching valve device is provided by providing an electromagnetic valve that is connected to a state in which rolling is suppressed while allowing curation, and can be switched between a communication state in which the two liquid passages are communicated and a cutoff state in which the two liquid passages are blocked. If the valve control device for controlling is a switching valve control device, articulation can be allowed or suppressed. Alternatively, a switching valve device capable of switching between a communication path for communicating the two hydraulic pressure chambers of the rotary actuators on the front wheel side and the rear wheel side, a communication state for communicating the communication path, and a shut-off state for blocking the communication valve device, and control thereof A switching valve control device may be provided. The rotary actuator is not limited to that described in JP-A-2004-122944.
(7) The front hydraulic actuators are provided corresponding to the left and right front wheels of the vehicle, respectively, while the rear hydraulic actuators are provided corresponding to the left and right rear wheels of the vehicle, respectively, The switching valve device can realize a state where the articulation is allowed and a state where the hydraulic chambers of the two front hydraulic pressure actuators and the rear hydraulic pressure actuators are allowed to be suppressed (2 ) Or suspension system according to item (3).
It is a more specific example of the suspension system described in the above (2) or (3). For this suspension system, for example, the articulation permission device described in FIGS. 10 and 11 of the WO 2004/080735, the articulation permission device described in Japanese Patent Application No. 2005-313282, and the like can be employed.
(8) The stopping control unit includes a manual input device including a manual operation member, and a manual input corresponding control unit that switches the switching valve device to the suppression state based on an input by the manual input device. The suspension system according to any one of items) to (7).
The manual input corresponding control unit only needs to operate based on at least manual input by the manual input device. In addition to manual input, the manual input corresponding control unit is stopped by another additional condition, for example, a stop detection device that detects that the vehicle is stopped. It may be activated when an additional condition such as being detected as being in is satisfied.
(9) The suspension system according to (8), wherein the manual input device includes a jackup input device that is manually operated to input execution of jackup.
Before executing jackup, be sure to operate the jackup input device in the instruction manual etc., and the manual input corresponding control unit will change the switching valve according to the input of jackup information from the jackup input device. This is a mode in which the apparatus is switched to a suppressed state. There is an advantage that the device cost can be reduced, and if the jack-up input device is already provided for other purposes, it is only necessary to supply the input from the device to the manual input compatible control unit, The purpose can be achieved at a lower cost.
(10) The stop control unit detects a jackup execution, and the jackup detection unit automatically detects the jackup detection by the jackup detection unit and switches the switching valve device to the suppression state. The suspension system according to any one of (1) to (9), including a control unit.
The jackup detection unit may include, for example, a vehicle height change state based detection unit that detects jackup based on a change state of the vehicle height detected by the vehicle height detection device. In many cases, the vehicle height detection device is already provided for vehicle height control and vehicle body posture control. In that case, the vehicle height information acquisition for acquiring information from the vehicle height detection device to the control unit during stoppage. And a jack-up determination unit that determines execution of jack-up based on the acquired vehicle height information, and the object can be achieved relatively inexpensively. In addition, even if the operator starts jackup without performing jackup input, the jackup control unit automatically switches the switching valve device to the suppressed state, so that the usability can be improved.
As the jack-up determination unit, for example, in a vehicle that does not include a vehicle height control device or in a vehicle that includes a vehicle height control device, the vehicle height corresponding to one wheel is equal to or greater than a set value when the vehicle height control device is inoperative. A device that determines that jack-up has been performed when it becomes high can be employed. Furthermore, if the condition that the door is closed is added, it is possible to eliminate the possibility of an increase in the vehicle height due to the passenger getting off or unloading the luggage, and the set value can be set small. Thus, jack-up determination can be performed at an early stage.
In addition, the jack-up determination unit may be configured so that the vehicle height corresponding to one wheel has a slope that is equal to or less than a set value in a vehicle that does not include the vehicle height control device or in a vehicle that includes the vehicle height control device and the vehicle height control device is inoperative. It can also be determined that jack-up is being performed when the setting value is increased by a predetermined value or more. Jackup determination is performed by taking advantage of the fact that the increase in the vehicle height due to jackup is usually smaller in the increase gradient than the increase in the vehicle height caused by the passenger getting off or lowering the luggage.
(11) Based on the detection results of the stop state acquisition unit that acquires the stop state, the articulation detection unit that detects the articulation, and the stop state acquisition unit and the articulation detection unit. The suspension system according to any one of (1) to (10), further including an articulation corresponding control unit for stopping the vehicle that automatically switches the switching valve device to the suppression state.
The articulation detection unit can include, for example, a vehicle height information acquisition unit and an articulation determination unit. In this aspect, the articulation determination unit is substantially the same as the jack-up determination unit. It is also possible. However, it is not indispensable. For example, a table storing a plurality of standard change patterns of vehicle height corresponding to each of the four front, rear, left and right theories at the time of articulation is provided, and the actual vehicle height change patterns are those standard change patterns. It is also possible to detect the occurrence of articulation when it matches any of the above.
(12) A stop state information in which the control unit during stoppage acquires a stop state, and stop state information that automatically switches the switching valve device to the suppression state based on stop state information from at least the stop state acquisition unit The suspension system according to any one of (1) to (11), including a corresponding control unit.
While jack-up is performed while the vehicle is stopped, it is not usually necessary to allow articulation while the vehicle is stopped, so the switching valve device automatically switches to the suppressed state while the vehicle is stopped. By doing so, jacking up can be facilitated easily. For example, (a) two fluid passages connecting the corresponding fluid pressure chambers of the front hydraulic pressure actuator and the rear hydraulic pressure actuator described in relation to the above (5), and (b) them. In a suspension system including a hydraulic circuit including an electromagnetic on-off valve that controls communication and blocking of two liquid passages, the electromagnetic on-off valve is normally closed, and the vehicle travels on a good road such as an asphalt road. If a valve device control device is provided that keeps the electromagnetic on-off valve closed during times and when the vehicle is stopped, and keeps the electromagnetic on-off valve open when driving on rough roads, the valve device control device will respond to stop state information A control unit will be included. If this item is subordinate to any one of items (9) to (11), the one described in any one of items (9) to (11) may cause, for example, a stop state information corresponding control unit to malfunction. Can be used as an alternative to it.

  FIG. 1 shows a suspension system according to an embodiment of the claimable invention. This suspension system connects the right front wheel 10, the left front wheel 12, the right rear wheel 14, and the left rear wheel 16 to a vehicle body (not shown) while allowing relative movement in the vertical direction of both of them and is not shown. Includes suspension links, shock absorbers, suspension springs, etc. On the front wheel side, a stabilizer bar 20 is further included. The stabilizer bar 20 includes an intermediate rod portion 22 that extends in the lateral direction of the vehicle, and a right arm portion 24 and a left arm portion (not shown) that extend from both ends in a direction having components in the front-rear direction. Two portions of the intermediate rod portion 22 separated in the longitudinal direction are connected to corresponding portions of the vehicle body by connecting rods 28 and a hydraulic cylinder 30 extending in the vertical direction. The connecting rod 28 and the hydraulic cylinder 30 are connected to the intermediate rod portion 22 so as to be relatively rotatable at their lower ends, and are connected to the vehicle body so as to be relatively rotatable at their upper ends. As the hydraulic cylinder 30 expands and contracts, the stabilizer bar 20 rotates relative to the vehicle body around the connecting portion of the connecting rod 28 in a vertical plane parallel to the lateral direction of the vehicle. The right arm portion 24 of the stabilizer bar 20 is operatively connected to the right front wheel 10 via a lower arm 32 that is one of suspension links. Although not shown, the left arm is connected to the left front wheel 12 in the same manner. The left and right front wheels 12 and 10 are non-driven wheels and are steering wheels.

  On the other hand, on the rear wheel side, the suspension system includes a stabilizer bar 40. The stabilizer bar 40 includes an intermediate rod portion 42 that extends in the lateral direction of the vehicle, and a right arm portion 44 and a left arm portion 46 that extend from both ends thereof in a direction having components in the front-rear direction. Although not indispensable, in the present embodiment, the right rear wheel 14 and the left rear wheel 16 are rotatably held at both ends of the axle tube 48 and are rotationally driven by a driving device (not shown). The left and right rear wheels 16 and 14 are drive wheels. Like the stabilizer bar 20, the stabilizer bar 40 has two portions separated in the longitudinal direction of the intermediate rod portion 42 connected to corresponding portions of the vehicle body by a connecting rod 50 and a hydraulic cylinder 52, respectively. By the expansion and contraction of 52, the stabilizer bar 40 rotates relative to the vehicle body in a vertical plane parallel to the lateral direction of the vehicle around the connecting portion of the connecting rod 42. Further, each of the right arm portion 44 and the left arm portion 46 is rotatably connected to two portions separated in the longitudinal direction of the axle tube 48.

  The hydraulic cylinders 30 and 52 are connected to a hydraulic circuit 60 having a flow control unit 58 shown in FIG. Each of the hydraulic cylinders 30 and 52 includes a housing 62, a piston 64 and a piston rod 66, and hydraulic chambers 68 and 70 are formed on both sides of the piston 64. Fluid pressure chambers 68 and fluid pressure chambers 70 located on the same side of the fluid pressure cylinders 30 and 52 with respect to the piston 64 are connected by fluid passages 80 and 82, respectively. The fluid passage 80 is provided with valves 84 and 86, an accumulator 88 and a fluid pressure sensor 90. The valve 84 is a normally open electromagnetic on-off valve that switches the liquid passage 80 between a communication state and a cutoff state, and the valve 86 is a normally open switch that switches between the state where the accumulator 88 is communicated with the liquid passage 80 and the state where the liquid passage 80 is blocked. This is an electromagnetic on-off valve. The accumulator 88 absorbs the working fluid when the fluid pressure in the fluid passage 80 becomes excessive, and supplements the working fluid when the fluid pressure in the fluid passage 80 becomes too small. In the present embodiment, the accumulator 88 is provided on the rear wheel side of the liquid passage 80 from the valve 84.

Valves 92 and 94, an accumulator 96, and a hydraulic pressure sensor 98 are also provided on the liquid passage 82 side, similarly to the liquid passage 80 side. The liquid passages 80 and 82 are communicated with each other by a communication passage 102, and a valve 104 is provided in the communication passage 102. The valve 104 is a normally closed electromagnetic on-off valve that switches the communication path 102 between a communication state and a cutoff state.
The valves 84 and 86, the accumulator 88 and the hydraulic pressure sensor 90 on the liquid passage 80 side described above, the valves 92 and 94, the accumulator 96 and the hydraulic pressure sensor 98 on the liquid passage 82 side, the communication passage 102 and the valve 104, The distribution control unit 58 is configured.

  The distribution control unit 58 is controlled by the control unit 110. As shown in FIG. 3, the control unit 110 is mainly composed of a computer 112, and the hydraulic pressure sensors 90 and 98 are connected to the computer 112, and valves 84, 86, 92, 94, and 104 are provided. They are connected via a drive circuit 114. Further, a lateral G sensor 120, a jack up switch 122, a vehicle height control device 124, a wheel speed sensor 126, and a door switch 128 are connected. The lateral G sensor 120 detects a lateral acceleration of the vehicle body, and is a kind of roll state acquisition device. The jackup switch 122 is a switch operated by an operator before jackup is executed. The vehicle height control device 124 includes a fluid actuator provided between the front, rear, left and right wheels 10, 12, 14, 16 and the vehicle body, and a fluid supply / discharge device that controls the amount of fluid in the fluid actuator, This is a device that controls the vertical distance between the wheel and the vehicle body. The vehicle height control device 124 includes a vertical distance between the wheel and the vehicle body at a position corresponding to each of the wheels 10, 12, 14, and 16. Four vehicle height sensors 130 (one of which is representatively shown in FIG. 3) for detecting a deviation from the standard value are connected. The door switch 128 is provided on all doors such as a vehicle door and a luggage door, and one of them is representatively shown in FIG.

  Various control programs are stored in the ROM of the computer 112. Of these, a jack-up related program deeply related to the claimable invention is shown in FIG. This jackup-related program is repeatedly executed once every fixed minute time regardless of whether the main switch such as an ignition switch of the vehicle is on or off.

  First, in step 1 (hereinafter referred to as S1, the same applies to other steps), it is determined whether or not the flag F is ON. Usually, however, the determination result is NO. It is determined whether execution of high control is necessary. This determination includes a determination as to whether or not the vehicle height control needs to be started in a state where the vehicle height control is not being performed, and a determination as to whether or not the vehicle height control once started has been completed. During the vehicle height control, the determination result is YES, and the vehicle height control in S3 is executed. The details of the vehicle height control will not be described. If the determination result in S2 is NO, it is determined in S4 whether or not the vehicle is running. This determination is performed based on the detection result of the vehicle speed detection device 126. If the determination result is YES, the suspension system is controlled during traveling in S5. Although detailed illustration of this control is omitted, the following control is roughly performed.

  When the vehicle is traveling straight, the valves 84, 86, 92, 94, 104 are in their original positions shown in FIG. In this state, the hydraulic pressures detected by the hydraulic pressure sensors 90 and 98 are substantially predetermined values Pc and Pd. Here, the hydraulic pressure Pc of the upper hydraulic pressure chamber 68 detected by the hydraulic pressure sensor 90 is lower than the hydraulic pressure Pd of the lower hydraulic pressure chamber 70 detected by the hydraulic pressure sensor 98. In the piston 64, since the pressure receiving area facing the upper hydraulic pressure chamber 68 is larger than the pressure receiving area facing the lower hydraulic pressure chamber 70, the vehicle is traveling straight (a state where no external force is applied to the piston 64). Therefore, the hydraulic pressure in the lower hydraulic chamber 70 is higher. In each of the hydraulic cylinders 30 and 52, the forces opposite to each other against the piston 64 are balanced, so that the stabilizer bars 20 and 40 are not twisted, and the posture of the vehicle is kept substantially horizontal.

  When the vehicle is turning, the valves 84 and 92 of the liquid passages 80 and 82 are opened, and the valves 86 and 94 of the accumulators 88 and 96 and the valve 104 of the communication passage 102 are closed. In the right turn state of the vehicle, the vehicle tilts to the state where the outside of the turn (left side) is lowered by the roll moment based on the centrifugal force. On the front wheel side and the rear wheel side, the hydraulic pressure in the hydraulic chamber 68 on the upper side of the hydraulic cylinders 30 and 52 decreases, and the hydraulic pressure in the lower hydraulic chamber 70 increases. These upper fluid pressure chambers 68 are communicated with each other by a fluid passage 80, and the lower fluid pressure chambers 70 are communicated with each other by a fluid passage 82. The fluid pressures of the two upper fluid pressure chambers 68 are almost equal. Since the hydraulic pressures of the two lower hydraulic chambers 70 are substantially the same, there is almost no flow of hydraulic fluid between them. In the stabilizer bars 20, 40, the inclination of the intermediate rod portions 22, 42 is suppressed, twisting occurs, and elastic force is generated. The elastic force, that is, the force in the direction of separating the left wheels 12 and 16 and the vehicle body due to the restoring force, and the direction in which the right wheels 10 and 14 and the vehicle body are brought close to each other. Each force is applied to suppress the tilt of the vehicle body.

  In this case, the difference between the hydraulic pressure in the upper hydraulic pressure chamber 68 and the hydraulic pressure in the lower hydraulic pressure chamber 70 is a large force for tilting the vehicle, that is, a force applied to the piston 64 of the hydraulic cylinders 30 and 52. It gets bigger. The greater the roll moment, the greater the hydraulic pressure difference, and the relationship between the roll moment and the hydraulic pressure difference is predetermined. Further, since a substantially constant relationship is established between the hydraulic pressure in the upper hydraulic pressure chamber 68 and the hydraulic pressure in the lower hydraulic pressure chamber 70, the upper hydraulic pressure chamber 68 and the lower hydraulic pressure chamber 70 are A substantially constant relationship is also established between any one of the hydraulic pressures and the roll moment. Therefore, in the present embodiment, the relationship between the lateral G as the roll moment related amount and the higher hydraulic pressure of the liquid passages 80 and 82 is stored in a table.

In the left turn state of the vehicle, the vehicle tilts so that the right side, which is the outside of the turn, is lowered by the roll moment. In the hydraulic cylinders 30 and 52, the hydraulic pressure in the lower hydraulic chamber 70 is lowered, and the hydraulic pressure in the upper hydraulic chamber 68 is increased. The flow of the hydraulic fluid in the liquid passages 80 and 82 is suppressed, and the movement of the piston 64 in the hydraulic cylinders 30 and 52 is suppressed. The stabilizer bars 20 and 40 are twisted to generate an elastic force.
In the present embodiment, when the vehicle is in a turning state, it is assumed that the vehicle is in a rolling state, and a hydraulic pressure difference can occur in the hydraulic cylinders 30 and 52.

  In this case, when the higher hydraulic pressure in the fluid passages 80 and 82 is lower than the fluid pressure determined for the lateral G detected by the lateral G sensor 120, the fluid passages 80 and 82 or the hydraulic cylinders 30 and 52. It can be estimated that liquid leakage has occurred in at least one of the above. Therefore, when it is estimated that liquid leakage has occurred, both the valves 84 and 92 of the liquid passages 80 and 82 are switched to the closed state. As a result, the hydraulic cylinder 60 can be divided into two parts because the other hydraulic cylinder can be shut off from one hydraulic cylinder where the liquid leaked or the part where the liquid leak occurred in the liquid passage. In the other hydraulic cylinder, a hydraulic pressure difference can occur between two hydraulic chambers partitioned by a piston. Elastic force is generated in the stabilizer bars 20 and 40 on either the front wheel side or the rear wheel side, and the inclination of the vehicle is suppressed. Compared to the case where the hydraulic cylinders on both the front wheel side and the rear wheel side become inoperable, if any one of the hydraulic cylinders becomes operable, the reduction in the roll suppression effect of the vehicle can be suppressed. it can.

Further, for example, when the vehicle is traveling on a rough road, when the right front wheel and the left rear wheel move upward and the left front wheel and the right rear wheel move downward, the hydraulic cylinder 30 on the front wheel side The hydraulic pressure in the lower hydraulic chamber 70 is low, the hydraulic pressure in the lower hydraulic chamber 70 on the rear wheel hydraulic cylinder 52 is increased, and the hydraulic pressure in the upper hydraulic chamber 68 on the hydraulic cylinder 30 is increased. Is higher, and the hydraulic chamber 68 on the upper side of the hydraulic cylinder 52 is lower. And since the distribution | circulation of the hydraulic fluid in the liquid channel | paths 80 and 82 is permitted, the free inclination of the stabilizer bars 20 and 40 is permitted, and a twist does not arise. Thereby, articulation is allowed.
Further, in the straight traveling state of the vehicle, as described above, the fluid pressure in the upper fluid pressure chamber 68 and the fluid pressure in the lower fluid pressure chamber 70, that is, the fluid pressure in the fluid passages 80 and 82 are determined in advance. Should be in size.

  On the other hand, when a large hydraulic pressure difference occurs between the hydraulic chambers 68 and 70 of the hydraulic cylinder 30 and between the hydraulic chambers 68 and 70 of the hydraulic cylinder 52 in a turning state of the vehicle, or a sealing failure occurs. In such a case, the hydraulic fluid may leak from the high-pressure side hydraulic chamber toward the low-pressure side hydraulic chamber through the seal portion of the piston 64. Therefore, when the vehicle returns to the straight traveling state, the fluid pressures in the fluid passages 80 and 82 are different from the set values Pc and Pd, respectively. Even though the vehicle is in a straight traveling state, an elastic force is generated in the stabilizer bars 20 and 40, and thereby the vehicle may tilt. Therefore, in the present embodiment, when the vehicle is in a straight traveling state, that is, when it is estimated that the vehicle should be in a substantially horizontal posture, the fluid pressure of one of the fluid passages 80 and 82 is the other. When the pressure is higher than the set pressure of the liquid passage, the valve 104 is switched to the open state and the communication passage 102 is put in the communication state, and the liquid pressure in the liquid passages 80 and 82 is set to the predetermined set pressures Pc and Pd. To be.

When the determination results of S1, S2, and S4 are all NO, jackup control after S6 is performed.
In S <b> 6, it is determined whether or not information indicating that jackup is to be executed is input by the jackup switch 122. Since the operator is required to turn on the jack-up switch when performing jack-up according to the instruction manual or work standard manual, this operation is usually executed. Accordingly, the determination result in S6 is YES, the flag F is turned on in S11, and the valves 84 and 92 in the liquid passages 80 and 82 and the valves 86 and 94 corresponding to the accumulators 88 and 96 are closed in S12. The The valve 104 that is a normally closed valve of the communication passage 102 is kept closed. When these valves are closed, both the hydraulic cylinders 30 and 52 become inoperable, and both the stabilizer bars 20 and 40 become non-rotatable and restrain the vertical movement of the front and rear wheels relative to the vehicle body. It becomes. Since the articulation is suppressed, the wheel can be separated from the road surface by a relatively small amount of jack-up of the vehicle body.
Normally, even if the valves 86 and 94 corresponding to the accumulators 88 and 96 are kept open, the operating strokes of the hydraulic cylinders 30 and 52 are small, so that the valves 86 and 94 need to be closed. is not.

If the determination result in S6 is NO, it is determined in S7 whether or not the door is in a closed state. Based on the detection result of the door switch 128, it is determined whether or not all the doors such as the entrance door and the luggage door of the vehicle are in the closed state. If the determination result is YES, the threshold of the vehicle height increment is determined. The value is set to L1. On the other hand, if any door is open, the determination result in S7 is NO, and the threshold value is set to L2, which is larger than L1. Then, it is determined whether or not jackup has been performed by comparing the actual increase in vehicle height corresponding to the front, rear, left and right wheels with the threshold value L1 or L2, and if the determination result is YES, S11 , S12 are executed, and the articulation suppression state is set.
As described above, the operator is required to turn on the jack-up switch 122 before starting the jack-up, but there are cases where the operator forgets or does not operate because the user does not know. Even in such a case, when jackup is started, it is detected as early as possible, and articulation is suppressed.

  Further, the reason why the threshold values are set to different values (here, two levels) is as follows. When all the doors are closed, there is no possibility that the vehicle height will increase due to a decrease in load such as occupant getting off or unloading, so a relatively small threshold value L1 is used. It is detected that jack-up has occurred while the increase in height is relatively small. On the other hand, when one of the doors is in the open state, the vehicle height may increase due to the load reduction, so a relatively large threshold value L2 must be used, and detection of jackup execution is slightly delayed. It is unavoidable.

  As described above, the suspension system is brought into the articulation suppression state based on the operation of the jackup switch 122 (S6) or based on the detection of the jackup (S7 to S10). After the articulation suppression state is set, the suppression state is not released until the end of jackup is detected. This is because in the state where the articulation is suppressed, it is better that the wheel does not descend even if the jack-up switch 122 is erroneously turned OFF while the jack-up is performed and the wheel is away from the road surface.

Therefore, in the present embodiment, the articulation suppression state is released as follows.
In the articulation suppression state, the flag F is ON, the determination result in S1 is YES, and it is determined in S13 whether jack-up is completed. This determination can be made based on, for example, whether or not the vehicle height once increased has decreased to the normal vehicle height. Until the determination result in S13 is YES, S1 and S13 are repeated, and during that time, necessary work such as jack-up and wheel replacement is performed. When the work is finished, the jacked up car body is returned to its original position. As a result, the determination result in S13 is YES, the flag F is turned OFF in S14, and the state of the jack-up switch 122 is turned OFF in S15. The jack-up switch 122 is a switch that switches the output signal between ON and OFF each time it is pressed, and the output signal in the ON state is returned to the OFF state. In S16, the valves 84, 92, etc., closed in S12 are returned to the open state, and the articulation suppression state is released.

  As is clear from the above description, in this embodiment, the stabilizer bar 20 constitutes the front stabilizer bar, the stabilizer bar 40 is the rear stabilizer bar, the hydraulic cylinder 30 is the front hydraulic pressure actuator, and the hydraulic cylinder 52 is the hydraulic cylinder 52. Each of the post hydraulic actuators is configured. Further, the liquid passages 80 and 82 constitute a liquid passage network, the valves 84 and 92 constitute a switching valve device, and the control unit 110 constitutes a valve device control device, respectively. The part which performs S4 and S5 in the flowchart of 4 comprises a driving | running | working control part, and the part which performs S4 and S6-S16 comprises the control part during a stop. Further, the jack-up switch 122 constitutes a jack-up input device as a manual input device, and the portions that execute S6, S11, and S12 of the computer 112 constitute a manual input-compatible control unit. 130 and the part that executes S7 to S10 of the computer 112 is a jack-up detection part, and the part that executes S11 and S12 in response to the jack-up detection of the computer 112 is a jack-up control part or a stopped-articulation control part. Each is composed.

  As described above, jacking up can be facilitated by closing only one of the valves 84 and 92 instead of closing both the valves 84 and 92 of the liquid passages 80 and 82. If one of the valves 84 and 92 is closed, the flow of hydraulic fluid between the hydraulic cylinder 30 on the front wheel side and the hydraulic cylinder 52 on the rear wheel side can be suppressed even if the other of the valves 84 and 92 is open. Articulation can be suppressed and jack-up can be facilitated.

In the above embodiment, the control unit 110 opens the valves 84 and 92 of the liquid passages 80 and 82 and the valves 86 and 94 of the accumulators 88 and 96 while the vehicle is running, as long as there is no liquid leakage in the hydraulic circuit 60. Although it was supposed to be kept in the state, the control during running in S5 in FIG. 4 is performed when the roll G acquisition device such as the lateral G sensor 120 detects that the vehicle has started turning. It is also possible to change it to a thing which makes 94 and 94 closed. Alternatively, the valves 86 and 94 of the accumulators 88 and 96 can be kept open, and the valves 84 and 92 of the liquid passages 80 and 82 can be closed, and these aspects can also be claimed. This is an example.
As described above, even when the valves 84 and 92 of the fluid passages 80 and 82 are kept open, the upper fluid pressure chambers 68 of the fluid pressure cylinder 30 and the fluid pressure cylinder 52 and the fluid pressure on the lower side are both rolled. When the hydraulic pressure between the chambers 70 increases or decreases, the operation of the hydraulic cylinders 30 and 52 is suppressed and rolling is suppressed, but all the valves 84, 92, 86 and 94 are closed. Then, the operation of the hydraulic cylinders 30 and 52 is blocked, and if the valves 84 and 92 of the liquid passages 80 and 82 are kept closed, the operation of the hydraulic cylinder 30 is blocked and the rolling is further increased. It is suppressed well.
In this embodiment, it is also possible to omit the detection of the liquid leakage and the switching of the valves 84 and 92 of the liquid passages 80 and 82 to the closed state in accordance with the detection in the above-described embodiment.

  As is clear from the above description, in the present embodiment, (a) a part for detecting that the vehicle has started turning, (b) valves 84, 92, 86, The part that closes all of 94, or the part that keeps the valves 84 and 92 of the liquid passages 80 and 82 closed while the valves 86 and 94 of the accumulators 88 and 96 are opened is the swivel control unit. Is configured.

In the two embodiments described above, the control unit during stoppage sets the switching valve device to an articulation suppressed state at the time of jackup based on an input from the manual input device or according to detection of jackup by the jackup detection unit. Although it was supposed to be switched, it is also possible to switch the switching valve device to the articulation suppression state based on the stop state information. For example, instead of the program represented by the flowchart of FIG. 4, the program represented by the flowchart of FIG. 5 is stored in the ROM of the computer 112.
In the flowchart of FIG. 5, the same step code indicates the same processing as each step in the above embodiment, so that the description is omitted, and only different steps are described. If the determination in S4 is NO, S11 and S12 are executed, and the switching valve device (valves 84, 92, 86, 94, or valves 84, 92) is brought into an articulation suppressed state. On the other hand, if the determination result in S4 is YES, it is determined in S21 whether or not the flag F is ON. If it is not ON, the running control in S5 is executed. If the flag F is ON, the switching valve device is returned to the articulation allowable state in S22, and the flag F is turned OFF in S23.
In this aspect, the vehicle speed detection device 126 and the part that executes S4 of the computer 112 constitute a stop state acquisition unit, and the part that executes S11 and S12 of the computer 112 constitutes a stop state information correspondence control unit. become.

Yet another embodiment is shown in FIG. In the present embodiment, hydraulic cylinders 210 and 212 are provided between lower arms 204 and 206 as suspension arms and a vehicle body side member (not shown) for the right front wheel 200 and the left front wheel 202. The lower arms 204 and 206 are held on the vehicle body side member so as to be swingable at the connecting portions 214 and 216.
Further, hydraulic cylinders 226 and 228 are provided between the axle housing 224 and the vehicle body side member for the right rear wheel 220 and the left rear wheel 222, respectively.
Reference numeral 232 denotes a torsion bar. The torsion bar 232 is fixed to the connecting portions 214 and 216 at one end, and is fixed to the vehicle body side member at the other end. An elastic force is generated by torsion of the torsion bar 232, and rolling of the vehicle is suppressed. However, providing the torsion bar 232 is not essential. Furthermore, the torsion bar 232 can be provided in a state where the left and right wheels are connected to function as a stabilizer bar. Further, it can be provided not only on the front wheel side but also on the rear wheel side.

  The hydraulic cylinders 210, 212, 226, and 228 extend in the vertical direction of the vehicle. As shown in FIG. 7, the housing 240 and the interior of the housing 240 are divided into two hydraulic chambers 242 and 244. A partitioning piston 246. In the present embodiment, the housing 240 is connected to the vehicle body side member, and the piston rod 248 is connected to the wheel side members (on the front wheel side to the lower arms 204 and 206 and on the rear wheel side to the axle housing 224). Yes. In each of the hydraulic cylinders 210, 212, 226, and 228, the hydraulic chamber 242 is positioned above the piston 246, and the hydraulic chamber 244 is positioned below the piston 246.

In the present embodiment, the two fluid pressure chambers 242, 244 corresponding to each other are connected by a fluid passage. Corresponding hydraulic chambers refer to the hydraulic chambers whose hydraulic pressure increases when the vehicle rolls or the hydraulic chambers whose hydraulic pressure decreases. The hydraulic cylinder 242 above the right front wheel hydraulic cylinder 210 and the right rear wheel hydraulic cylinder 226 and the hydraulic cylinder 244 below the left front wheel hydraulic cylinder 212 and the hydraulic cylinder 244 below the left rear wheel correspond to each other. These hydraulic chambers are connected by a liquid passage 250. Similarly, the hydraulic chamber 244 below the hydraulic cylinder 210 for the right front wheel, the hydraulic cylinder 226 for the right rear wheel, the hydraulic cylinder 212 for the left front wheel, and the hydraulic chamber 242 above the hydraulic cylinder 228 for the left rear wheel. Are hydraulic chambers corresponding to each other, and these hydraulic chambers are connected by a liquid passage 252. These liquid passages 250 and 252 are connected by a communication passage 254.
The fluid passages 250 and 252 correspond to the first portions 260 and 262 that connect the corresponding hydraulic chambers of the hydraulic cylinders 210 and 212 of the left and right front wheels and the hydraulic cylinders 226 and 228 of the left and right rear wheels, respectively. Second portions 264 and 266 that connect the hydraulic chambers to each other, and third portions 270 and 272 that connect the first liquid passage portions 260 and 262 and the second liquid passage portions 264 and 266.
One of the first parts 260 and 262 (the first part 260 in the illustrated example) is provided with a valve 274 that is a normally open electromagnetic on-off valve, and one of the second parts 264 and 266 (the second part in the illustrated example). H.264 also includes a valve 276 that is a normally open electromagnetic on-off valve, and valves 280 and 282 that are normally open electromagnetic on-off valves are provided on the third portions 270 and 272, respectively. Is provided with a valve 284 which is a normally closed electromagnetic on-off valve, and a hydraulic pressure sensor 286 is further provided on the third portions 270 and 272.

The first portions 260 and 262 are provided with accumulators 290 and 292, respectively, and the second portions 264 and 266 are provided with accumulators 291 and 293, respectively. The hydraulic fluid is exchanged between the accumulators 290 to 293 and the liquid passages 250 and 252, thereby preventing the liquid pressure in the liquid passages 250 and 252 from becoming excessive or negative.
Damper valves 294 are provided between the accumulators 290 to 293 and the liquid passages 250 and 252, respectively, in the vicinity of the connection portion between the liquid passages 250 and 252 and the hydraulic pressure chambers 244 of the hydraulic cylinders 210, 212, 226 and 228. Also, a damper valve 296 is provided for each. The damper valves 294 and 296 have a throttling function, generate a damping force against the flow of hydraulic fluid, and obtain a vibration damping effect.
The damper valves 294 and 296 may have any structure as long as they have a throttle function. For example, the degree of restriction may be fixed, or an electromagnetic valve with variable degree of restriction may be used. In the case of an electromagnetic valve, even if it is an electromagnetic open / close valve that can be opened and closed by turning on and off the supply current, it is an electromagnetic control valve that can control the degree of restriction (flow channel area) to a magnitude corresponding to the supply current. There may be. Further, the flow of hydraulic fluid between the fluid passages 250 and 252 and the accumulators 290 and 292 and the hydraulic pressure chamber 244 has a throttle function in the flow of hydraulic fluid in one direction, and the throttle function in the other flow. Or having a throttling function in the flow in both directions. Further, the damper valve can be provided corresponding to the hydraulic chamber 242.

  In the present embodiment, the hydraulic cylinders 210, 212, 226, 228, liquid passages 250, 252, communication passage 254, valves 274, 276, 280, 282, 284, hydraulic pressure sensor 286, accumulators 290, 291, 292 293, damper bubbles 294, 296, etc. constitute a hydraulic circuit 298.

When the valves 274, 276, 280, and 282 of the suspension system are open and the valve 284 is closed, the hydraulic cylinders 210, 212, 226, and 228 have corresponding hydraulic pressures when a roll moment is applied to the vehicle body. Since both chambers increase in hydraulic pressure or decrease in hydraulic pressure, the hydraulic cylinders 210, 212, 226, and 228 hardly operate, and rolling is suppressed.
On the other hand, of the hydraulic cylinders 210, 212, 226, and 228, a force for contraction is applied to two on one diagonal, and a force for expansion is applied to two on the other diagonal. In this case, since the flow of the hydraulic fluid is not hindered by the valves 274, 276, 280, 282, the contraction and extension of the hydraulic cylinders 210, 212, 226, 228 are allowed. The generation of articulation is allowed.
If the valves 274, 276, 280, and 282 are closed, articulation is suppressed. By closing the valves 280 and 282, the communication between the hydraulic cylinders 210 and 212 on the front wheel side and the hydraulic cylinders 226 and 228 on the rear wheel side is blocked, and then the valve 274 is closed. As a result, the transfer of hydraulic fluid between the hydraulic cylinders 210, 212 on the front wheel side is blocked, and the transfer of hydraulic fluid between the hydraulic cylinders 226, 228 on the rear wheel side is blocked by closing the valve 276. This is because the operation of all the hydraulic cylinders 210, 212, 226, and 228 is blocked.

When this embodiment is compared with the embodiment described in FIGS. 1 and 2, the combination of the hydraulic cylinders 210, 212, 226, 228 and the liquid passages 250, 252 is the combination of the stabilizer bars 20, 40 and the liquid. Functions similar to the combination of the pressure cylinders 30 and 52 and the fluid passages 80 and 82 are performed, and the valves 274 and 276 or the valves 274, 276, 282 and 284 perform functions similar to the valves 84 and 92. Further, the valve 284 performs a function similar to the valve 104, and the hydraulic pressure sensor 286 performs a function similar to the hydraulic pressure sensors 90 and 98.
The valves corresponding to the valves 86 and 94 in the embodiment of FIGS. 1 and 2 are not provided in this embodiment, and the valves corresponding to the damper valves 294 and 296 of this embodiment are shown in FIGS. It is not provided in the embodiment.

  As described above, the present suspension system has similar components to those in the embodiments of FIGS. 1 and 2 with respect to rolling suppression and articulation tolerance and suppression. By providing a control unit for controlling the valves 274, 276, 280, 282, and 284, the plurality of embodiments (the embodiment of FIGS. 1 to 4 and the embodiment of FIGS. It is possible to perform jack-up related control similar to the modified embodiment, the embodiment of FIG. In particular, the jack-up can be facilitated by closing all the valves 274, 276, 280 and 282 as necessary.

  Thus, by making all the valves 274, 276, 280 and 282 closed, it is possible to reliably achieve jack-up, but when the vehicle is stopped on a horizontal plane, etc. Normally, jack-up can be facilitated by simply closing the valve valves 280 and 282 without closing the valves 274 and 276. For example, when the right front wheel 200 side is jacked up and the right front wheel 200 tends to descend relative to the vehicle body, the hydraulic pressure in the hydraulic chamber 244 below the hydraulic cylinder 210 increases, It tries to flow into the hydraulic chamber 242 on the upper side of the hydraulic cylinder 212 on the left front wheel 202 side through the first portion 262, but when the jack on the right front wheel 200 side is jacked up, the load on the hydraulic cylinder 212 on the left front wheel 202 side is increased. Further, since the hydraulic pressure in the hydraulic chamber 242 of the hydraulic cylinder 212 increases, the flow of hydraulic fluid in the first portion 262 is suppressed (rather, a reverse flow occurs), and the right front wheel 200 is relative to the vehicle body. Therefore, jacking up is facilitated. From this point of view, the valves 274 and 276 can be omitted.

  Further, as described above, instead of closing the valve valves 280 and 282 without closing the valves 274 and 276, only the other of the valves 280 and 282 is not closed without closing the valves 274 and 276 and one of the valve valves 280 and 282. Even if is closed, jack-up can be facilitated. If the other of the valves 280 and 282 is closed, even if one of the valves 280 and 282 is open, the flow of hydraulic fluid between the front wheel side and the rear wheel side can be suppressed. It is possible to facilitate this.

Yet another embodiment is shown in FIG.
In this embodiment, shock absorbers 330, 332, 334, and 336 as hydraulic actuators are provided on the right front wheel 320, the left front wheel 322, the right rear wheel 324, and the left rear wheel 326, respectively. Since these shock absorbers have the same structure, the shock absorber 330 will be described, and other shock absorbers will be denoted by the same reference numerals and description thereof will be omitted.

  The shock absorber 330 is provided with a housing 340, a piston 342, a piston rod 344, a hydraulic pressure chamber 346, 348 as in the embodiment of FIGS. 6 and 7, but the communication path having a fixed throttle 354 in the piston 342. And the connection port is provided with a variable throttle 356, which is different in that a damping force generator is included. A low pressure accumulator 358, a high pressure accumulator 360, and a spring characteristic switching valve 362 are connected to the connection port. When the spring characteristic switching valve 362 is in the open state, both the low pressure and high pressure accumulators 358 and 360 are communicated with the shock absorber 320 to have low spring characteristics. When the spring characteristic switching valve 362 is in the closed state, only the high pressure accumulator 360 is present. Is communicated with the shock absorber 320 and has high spring characteristics.

  The shock absorbers 330, 332, 334, 336 and the corresponding low-pressure and high-pressure accumulators 358, 360 are connected to the control cylinder 380 by liquid passages 372, 374, 376, 378, respectively. The control cylinder 380 includes a stepped housing 382 having a central large-diameter portion and small-diameter portions on both ends, and a stepped piston 384 fitted in a liquid-tight and slidable manner with four hydraulic pressures. Chambers 386, 388, 390, 392 are provided. The effective pressure receiving areas of the stepped piston 384 with respect to the hydraulic chamber 386 and the hydraulic chamber 392 on the end side are the same, and the pressure receiving areas of the central hydraulic chamber 388 and the hydraulic chamber 390 are also the same. The effective pressure receiving area of the stepped piston 384 with respect to the hydraulic pressure chambers 386 and 392 and the effective pressure receiving area with respect to the hydraulic pressure chambers 388 and 390 can be equal to each other, the former can be increased, or the latter can be increased. It is. Liquid passages 376 and 378 connected to at least one of the end-side hydraulic chambers 386 and 392 and the central-side hydraulic chambers 388 and 390 (the central-side hydraulic chambers 388 and 390 in the illustrated example) Valves 394 and 396, which are normally open electromagnetic on-off valves capable of blocking them, are provided.

  Individual passages 400, 402, 404, and 406 are connected to the fluid passages 372, 374, 376, and 378, respectively, and these individual passages are connected to a fluid pressure source 412 through a common passage 410. Individual valves 400, 416, 418, 420 are provided in the individual passages 400, 402, 404, 406, respectively, and the shock absorbers 330, 332, 334, 336 are individually communicated with the hydraulic pressure source 412, and the shock absorbers 330, The vehicle height can be controlled by increasing or decreasing the amount of hydraulic fluid in 332, 334, 336. The individual passages 400, 402, 404, 406, the common passage 410, the hydraulic pressure source 412, and the individual valves 414, 416, 418, 420 are jointly operated with the vehicle height control unit 432 of the suspension electronic control unit (ECU) 430. A control device 434 is configured. Along with the variable throttle 356 and the spring switching characteristic valve 362, four vehicle height sensors 436 provided corresponding to each of the shock absorbers 330, 332, 334, and 336 are connected to the suspension ECU 430. Based on the detection value of the sensor 436, the vehicle height control unit 432 and the suspension characteristic control unit 438 of the suspension ECU 430 respectively control the vehicle height and the suspension characteristic.

  Also in this suspension system, when the roll moment is applied, the hydraulic pressures of the shock absorbers 330, 332, 334, and 336 located on the right side and the left side of the vehicle both increase or decrease. The hydraulic pressure acting on the stepped piston 384 is substantially balanced and the control cylinder 380 does not operate, and rolling is suppressed. On the other hand, when articulation occurs, the hydraulic pressure between the diagonal absorbers among the shock absorbers 330, 332, 334, and 336 increases or decreases, so that it acts on the stepped piston 384 of the control cylinder 380. The hydraulic cylinder is out of balance and the control cylinder 380 is activated. As a result, the shock absorbers 330, 332, 334, and 336 can be easily operated, and articulation is allowed.

  On the other hand, when the valves 394 and 396 are closed and the liquid passages 376 and 378 are shut off, the operation of the control cylinder 380 is blocked and the articulation is suppressed. Therefore, also in this embodiment, a similar effect can be obtained by storing a program similar to the program represented by the flowcharts of FIGS. 4 and 5 in the computer of the suspension ECU 430.

Yet another embodiment is shown in FIG. In this embodiment, the claimable invention is applied to a particularly simple suspension system capable of suppressing rolling and allowing articulation.
Four hydraulic cylinders 452, 454, 456, and 458 are provided corresponding to the front, rear, left and right four wheels. Each hydraulic cylinder includes a housing 462, a piston 464, a piston rod 466, an upper hydraulic chamber 468, and a lower hydraulic chamber 470, respectively. The fluid pressure chambers 468 and the fluid pressure chambers 470 of the fluid pressure cylinders 452, 454, 456, and 458 communicate with each other by a fluid passage 476 and a fluid passage 478, respectively. One of these liquid passages 476 and 478 (liquid passage 476 in the illustrated example) is provided with a valve 480 that is an electromagnetic on-off valve that can be switched between a communication state for communicating the liquid passage 476 and a blocking state for blocking the liquid passage 476. The liquid passages 476 and 478 are provided with accumulators 484, respectively. The valve 480 is controlled by the control device 450.
The present suspension system also includes other components such as a suspension link in addition to the above, but illustration and detailed description thereof are omitted.

  While the vehicle is running, the valve 480 is kept in communication. Accordingly, it is allowed that one of the two sets of hydraulic cylinders that are diagonal to each other contracts and the other expands. Articulation is allowed. In addition, when the roll moment is applied, a force for contracting them acts on one of the two sets of hydraulic cylinders positioned on the right side and the left side, and a force for extending them is applied on the other. That is, the hydraulic pressures in the corresponding hydraulic chambers of the hydraulic cylinders located on the right and left sides both increase or decrease, so that almost no hydraulic fluid flows through the fluid passages 476 and 478, and the hydraulic cylinder 452. , 254, 456, and 458 hardly operate, and rolling of the vehicle body is suppressed.

Then, when it is necessary to suppress articulation, such as when jacking up, the control device 450 causes the valve 480 to be shut off. As a result, the flow of hydraulic fluid in the fluid passage 476 is blocked, and the hydraulic cylinders 452, 254, 456, and 458 are almost inoperable. The articulation is suppressed.
In this embodiment, the hydraulic cylinders 452 and 454 constitute the front hydraulic pressure actuator, the hydraulic cylinders 456 and 458 constitute the rear hydraulic pressure actuator, the liquid passages 476 and 478 constitute the liquid passage network, and 2 The two valves 480 constitute a switching valve device, and the control device 450 constitutes a switching valve control device.

  The above is literally an example, and the claimable invention further includes a suspension system including the hydraulic circuit shown in FIG. 14 of Patent Document 1, a suspension system not shown but variously described, The present invention can also be applied to a suspension system in which various changes are made to the hydraulic circuit and the actuator.

It is a perspective view which shows the principal part of the suspension system which is one Example of claimable invention. It is a hydraulic circuit diagram of the suspension system. It is a block diagram which shows the electric control part of the said suspension system. It is a flowchart which shows a part of program which controls the said suspension system. It is a flowchart which shows a part of program which controls the suspension system which is another Example. It is a perspective view which shows the principal part of the suspension system which is another Example. It is a figure which shows notionally the hydraulic circuit of the suspension system of FIG. It is a hydraulic-pressure circuit diagram which shows the suspension system which is another Example. It is a figure which shows notionally the hydraulic circuit of the suspension system which is another Example.

Explanation of symbols

10: Right front wheel 12: Left front wheel 14: Right rear wheel 16: Left rear wheel 20: Stabilizer bar 22: Intermediate rod part 24: Right arm part 28: Connecting rod 30: Hydraulic cylinder 32: Lower arm 40: Stabilizer bar 42: Intermediate rod part 44: Right arm part 46: Left arm part 50: Connecting rod 52: Hydraulic cylinder 58: Flow control unit 60: Hydraulic circuit 62: Housing 64: Piston 68, 70: Hydraulic chamber 80, 82: Liquid Passage 84, 86, 92, 94: Valve 88, 96: Accumulator 90: Fluid pressure sensor 102: Communication passage 104: Valve 110: Control unit 120: Lateral G sensor 122: Jack up switch 124: Vehicle height control device 126: Vehicle speed Detection device 128: Door switch H 130: vehicle height sensor 226, 228: hydraulic cylinder 250, 252: liquid passage 254: communication passage 260, 262: first part 264, 266: second part 270, 272: third part 274, 276, 280, 282, 284: Valve 286: Hydraulic pressure sensor 290, 291, 292, 293: Accumulator 294, 296: Damper valve 298: Hydraulic pressure sensor 330.3332.334.336: Shock absorber 354: Fixed throttle 356: Variable throttle 358: Low pressure Accumulator 360: High pressure accumulator 362: Spring characteristic switching valve 372, 374.376, 378: Liquid passage 380: Control cylinder 382: Stepped housing 384: Stepped piston 386, 388, 390, 392: Pressure chamber 394, 396; Valve 412: Hydraulic pressure source 414, 416, 418, 420: Individual valve 430: Suspension electronic control device 432: Vehicle height control unit 434: Vehicle height control device 436: Vehicle height sensor 438: Suspension characteristic control Part 452, 454, 456, 458: Hydraulic cylinder 468, 470: Hydraulic chamber 476, 478: Liquid passage 480: Valve 484: Accumulator 450: Control device

Claims (8)

In a suspension system that can take a state that suppresses rolling and allows articulation while the vehicle is running,
A suspension system comprising an articulation suppression device that stops articulation while the vehicle is stopped. One or more front hydraulic actuators that are provided corresponding to the left and right front wheels provided on the left and right of the front side of the vehicle, and that operate in accordance with the vertical movement of the left and right front wheels relative to the vehicle body;
One or more rear hydraulic actuators provided corresponding to the left and right rear wheels provided on the left and right of the rear side of the vehicle, and operating in accordance with the vertical movement of the left and right rear wheels relative to the vehicle body;
A liquid passage network including one or more liquid passages connecting the corresponding fluid chambers of the front hydraulic pressure actuator and the rear hydraulic pressure actuator;
Provided in the liquid passage network, the state of communication between the front hydraulic pressure actuator and the rear hydraulic pressure actuator via the liquid passage network is allowed to allow articulation and to suppress articulation. A switching valve device for switching to a suppressed state;
A valve device control device that controls switching of the switching valve device, and the valve device control device comprises:
A traveling control unit that switches the switching valve device between the permissible state and the restrained state at least at one time during travel of the vehicle;
A suspension control unit that switches the switching valve device to the suppressed state at least at one time during a stop of the vehicle.   The suspension system according to claim 2, wherein the traveling control unit includes a turning correspondence control unit that keeps the switching valve device in an allowable state while the vehicle is traveling straight ahead and switches to a restrained state when the vehicle is turning. A front stabilizer bar that is disposed with respect to the left and right front wheels and is rotatable relative to the vehicle body in a vertical plane parallel to a lateral direction of the vehicle;
A rear stabilizer bar disposed with respect to the left and right rear wheels and rotatable relative to the vehicle body in a vertical plane parallel to a lateral direction of the vehicle, the front hydraulic pressure actuator and the rear hydraulic pressure 4. The suspension system according to claim 2, wherein the actuator can change each of the front stabilizer bar and the rear stabilizer bar between a state in which relative rotation with respect to the vehicle body is suppressed and a state in which the actuator is allowed.   The front hydraulic actuators are provided corresponding to the left and right front wheels of the vehicle, respectively, while the rear hydraulic actuators are provided corresponding to the left and right rear wheels of the vehicle, respectively, and the liquid passage network and the switching valve The apparatus is capable of realizing a state in which the articulation is allowed and a state in which the hydraulic chambers of the two front hydraulic pressure actuators and the rear hydraulic pressure actuators are allowed to be suppressed. Suspension system described in.   Corresponding to manual input for switching the switching valve device to the suppression state based on an input to the jack-up input device, and a jack-up input device that is manually operated to input the jack-up execution by the control unit during the stop The suspension system according to claim 1, further comprising a control unit.   The stop control unit detects a jackup execution, and a jackup control unit that automatically switches the switching valve device to the suppression state based on the jackup detection by the jackup detection unit. A suspension system according to any one of claims 1 to 6.   The stop state acquisition unit that acquires the stop state, and the stop state information corresponding control unit that automatically switches the switching valve device to the suppression state based on stop state information from at least the stop state acquisition unit. A suspension system according to any one of claims 1 to 7.

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