JP2021130311A - Suspension device - Google Patents

Abstract

To provide a suspension device which can achieve both steering stability and riding comfort of a vehicle.SOLUTION: An accumulator device 25 which is provided by connecting to at least one connection duct of first and second connection ducts 5, 6 includes a first accumulator 27, second accumulators 30, 31 which are connected to the first accumulator 27 in parallel and are large in volume, a normally closed type first control valve 32 which is provided on upstream side of the second accumulators 30, 31, and a stationary orifice 34 which is positioned between the connection ducts and the second accumulators 30, 31, and is provided in parallel to the first control valve 32. Flow passage area of the stationary orifice 34 is formed sufficiently small for limiting flow of working liquid within the connection ducts caused by stroke of hydraulic cylinders 1-4.SELECTED DRAWING: Figure 1

Description

The present invention relates to a suspension device suitably used for buffering vibration of, for example, a four-wheeled vehicle.

Generally, in a vehicle such as a four-wheeled vehicle, a hydraulic cylinder is provided between the left and right wheel sides and the vehicle body side, and upward and downward vibrations generated during running and left and right directions occur. Suspension devices having a configuration that buffers roll vibration and the like are known. As such a suspension device, there is a related suspension device in which the upper chamber and the lower chamber of the left and right hydraulic cylinders are piped in a cross in order to achieve both the ability of the vehicle to run on rough roads and the maneuverability on good roads. (See, for example, Patent Documents 1 and 2).

Japanese Patent No. 4674882 JP-A-2015-120364

By the way, the suspension device according to the prior art has a problem that it is not always possible to sufficiently achieve both steering stability and riding comfort of the vehicle.

An object of the present invention is to provide a suspension device capable of achieving both steering stability and riding comfort of a vehicle.

In order to solve the above-mentioned problems, the configuration adopted by the present invention is interposed between the left and right wheels and the vehicle body, respectively, and the inside of the cylinder is defined as an upper chamber and a lower chamber by a piston. , The upper chamber of one hydraulic cylinder communicates with the lower chamber of the other hydraulic cylinder between the right hydraulic cylinder and the left and right hydraulic cylinders, and the upper chamber of the other hydraulic cylinder is said. Attenuates to at least one of the first and second connecting pipelines, which are connected by a cross so as to communicate with the lower chamber of one hydraulic cylinder, and the first and second connecting pipelines. A suspension device having an accumulator device connected via a force generating mechanism, wherein the accumulator device includes a first accumulator, a second accumulator connected in parallel with the first accumulator, and the first accumulator. 2 It has a first control valve provided on the upstream side of the accumulator and a fixed orifice located between the connecting pipeline and the second accumulator and provided in parallel with the first control valve, and is fixed. The flow path area of the orifice is sufficiently small to limit the flow of the hydraulic fluid in the connecting pipeline generated by the stroke of the hydraulic cylinder to such an extent that it does not affect the damping force generated by the damping force generating mechanism. It is characterized by that.

According to the present invention, it is possible to achieve both steering stability and riding comfort of the vehicle.

It is an overall block diagram which shows the suspension apparatus by 1st Embodiment of this invention. It is a hydraulic circuit diagram which shows the accumulator device in FIG. 1 enlarged. It is a control block diagram which shows the controller which switches and controls the bridge valve and the 1st and 2nd control valves in FIG. It is a perspective view which shows the concrete structure by enlarging the accumulator device in FIG. It is a characteristic diagram which shows the relationship between the displacement of a wheel and the accumulator pressure. It is a characteristic diagram which shows the relationship between a gas volume and a roll rigidity. It is a flow chart which shows the switching control processing of a bridge valve by a controller. It is a flow chart which shows the switching control processing of the 1st control valve by a controller. It is a hydraulic circuit diagram which shows the accumulator device by the 2nd Embodiment in an enlarged manner.

Hereinafter, a case where the suspension device according to the embodiment of the present invention is applied to a four-wheeled vehicle will be described in detail with reference to the accompanying drawings.

Here, FIGS. 1 to 8 show the first embodiment of the present invention. In FIG. 1, the left and right hydraulic cylinders (hereinafter referred to as the left hydraulic cylinder on the front wheel side and the right hydraulic cylinder 2 on the front wheel side) are the vehicle body and the left and right front wheels (neither shown). Each is intervened between. The left and right hydraulic cylinders on the rear side (hereinafter referred to as the left hydraulic cylinder 3 on the rear wheel side and the right hydraulic cylinder 4 on the rear wheel side) are the vehicle body and the left and right rear wheels (neither shown). ) And each.

These hydraulic cylinders 1 to 4 are cylinder devices that connect between the vehicle body (upper spring) and each wheel (unsprung) and expand and contract according to the relative movement of the vehicle body and each wheel. It constitutes a shock absorber that cushions vibration. For example, the left hydraulic cylinder 1 on the front wheel side includes a cylinder 1A made of a bottomed cylindrical tube, a piston 1B slidably inserted in the cylinder 1A, and one end side fixed to the piston 1B and the other end side. It is configured to include a piston rod 1C protruding outside the cylinder 1A. The inside of the cylinder 1A is defined by the piston 1B into two chambers above and below (that is, an upper chamber A and a lower chamber B).

Similarly, the other hydraulic cylinders 2, 3 and 4 are also configured to include cylinders 2A, 3A, 4A, pistons 2B, 3B, 4B and piston rods 2C, 3C, 4C. The insides of the cylinders 2A, 3A, and 4A are defined by the pistons 2B, 3B, and 4B into two upper and lower chambers (that is, an upper chamber A and a lower chamber B), respectively.

The first and second connecting pipes 5 and 6 are provided as cross pipes between the left hydraulic cylinder 1 and the right hydraulic cylinder 2 on the front wheel side, and are connected by a cross between the two. Of these, the first connecting pipeline 5 is arranged so as to extend between the cylinders 1A and 2A in the left and right directions so as to communicate between the upper chamber A in the cylinder 1A and the lower chamber B in the cylinder 2A. ing. The second connecting pipeline 6 is arranged so as to extend between the cylinders 1A and 2A in the left and right directions so as to communicate between the lower chamber B in the cylinder 1A and the upper chamber A in the cylinder 2A. ..

The left hydraulic cylinder 1 on the front wheel side is provided with a damping force control valve 7 at a connection portion between the upper chamber A and the first connecting pipe line 5. The damping force control valve 7 has a damping valve that controls the damping force of the pressure oil flowing out from the upper chamber A toward the first connecting pipe 5 and damps the flow from the upper chamber A. Further, the damping force control valve 7 has a check valve 7A that allows the pressure oil to flow from the first connecting pipe line 5 toward the upper chamber A and blocks the flow in the opposite direction.

The left hydraulic cylinder 1 on the front wheel side is provided with a damping force control valve 8 at a connection portion between the lower chamber B and the second connecting pipe line 6. The damping force control valve 8 has a damping valve that controls the damping force of the pressure oil flowing out from the lower chamber B toward the second connecting pipeline 6 and damps the flow from the lower chamber B. Further, the damping force control valve 8 has a check valve 8A that allows the pressure oil to flow from the second connecting pipe 6 toward the lower chamber B and blocks the flow in the opposite direction.

The right hydraulic cylinder 2 on the front wheel side is provided with a damping force control valve 9 at a connection portion between the upper chamber A and the second connection pipeline 6, and a connection portion between the lower chamber B and the first connection pipeline 5. Is provided with a damping force control valve 10. These damping force control valves 9 and 10 have damping valves that dampen the flow from the upper chamber A and the lower chamber B in the same manner as the damping force control valves 7 and 8 described above. Further, the damping force control valves 9 and 10 have check valves 9A and 10A like the damping force control valves 7 and 8.

The left hydraulic cylinder 3 and the right hydraulic cylinder 4 on the rear wheel side are connected by a cross by the first and second connecting pipes 11 and 12 as cross pipes. That is, the first connecting pipeline 11 is arranged so as to extend between the cylinders 3A and 4A in the left and right directions so as to communicate between the upper chamber A in the cylinder 3A and the lower chamber B in the cylinder 4A. ing. The second connecting pipeline 12 is arranged so as to extend between the cylinders 3A and 4A in the left and right directions so as to communicate between the lower chamber B in the cylinder 3A and the upper chamber A in the cylinder 4A. ..

The left hydraulic cylinder 3 on the rear wheel side is provided with a damping force control valve 13 at the connection portion between the upper chamber A and the first connection pipe 11, and connects the lower chamber B and the second connection pipe 12. A damping force control valve 14 is provided at the portion. These damping force control valves 13 and 14 have damping valves that dampen the flow from the upper chamber A and the lower chamber B in the same manner as the damping force control valves 7 and 8 described above. Further, the damping force control valves 13 and 14 have check valves 13A and 14A like the damping force control valves 7 and 8.

The right hydraulic cylinder 4 on the rear wheel side is provided with a damping force control valve 15 at the connection portion between the upper chamber A and the second connection pipe 12, and connects the lower chamber B and the first connection pipe 11. A damping force control valve 16 is provided at the portion. These damping force control valves 15 and 16 have damping valves that dampen the flow from the upper chamber A and the lower chamber B in the same manner as the damping force control valves 7 and 8 described above. Further, the damping force control valves 15 and 16 have check valves 15A and 16A like the damping force control valves 7 and 8.

Next, the front connecting path 17 is a pipeline that communicates and shuts off between the first and second connecting pipelines 5 and 6 via the bridge valve 18 on the front wheel side. The bridge valve 18 on the front wheel side is composed of a normally closed solenoid valve, and is normally held at the closed position (a) so as to block the flow of pressure oil (liquid) along the front connecting path 17. .. However, when the valve closing position (a) is switched to the valve opening position (b) by energization from the controller 43, which will be described later, the pressure oil of the bridge valve 18 is between the first and second connecting pipes 5 and 6. Allows distribution through the front connecting path 17. Therefore, while the bridge valve 18 is switched to the valve opening position (b), the upper chamber A and the lower chamber B of the hydraulic cylinders 1 and 2 pass through the damping force control valves 7, 8, 9, and 10. It will be in a state of communication.

The front connecting path 17 is provided with a bypass path 19 bypassing the bridge valve 18, and the bypass path 19 is provided with a throttle 20 for limiting the flow of pressure oil. The throttle 20 presses through the bypass path 19 when a pressure difference occurs in the front connecting passage 17 (that is, between the first and second connecting pipes 5 and 6) before and after the bridge valve 18. Allows the oil to gradually flow from higher pressure to lower pressure. Therefore, the pressure difference between the first and second connecting pipes 5 and 6 is gradually eliminated by the throttle 20, and the pressures of both are made uniform with a delay time.

On the other hand, the rear connecting path 21 is a pipeline that communicates and shuts off between the first and second connecting pipelines 11 and 12 via the bridge valve 22 on the rear wheel side. The bridge valve 22 on the rear wheel side is composed of a solenoid valve like the bridge valve 18 on the front wheel side, and is normally closed so as to block the flow of pressure oil (liquid) along the rear connecting path 21. It is held in (a). However, when the valve closing position (a) is switched to the valve opening position (b) by energization from the controller 43, which will be described later, the pressure oil of the bridge valve 22 is between the first and second connecting pipes 11 and 12. Allows distribution via the rear connecting path 21. Therefore, while the bridge valve 22 is switched to the valve opening position (b), the upper chamber A and the lower chamber B of the hydraulic cylinders 3 and 4 on the rear wheel side are the damping force control valves 13, 14, 15, and so on. It becomes a state of communicating through 16.

The right side connecting passage 23 is a pipe line that always communicates the front side connecting line 5 and the rear side connecting line 12 at a position close to the right hydraulic cylinder 2 on the front wheel side and the right hydraulic cylinder 4 on the rear wheel side. .. The left side connecting passage 24 is a pipe line that always connects the front side connecting line 6 and the rear side connecting line 11 at a position close to the front wheel side left hydraulic cylinder 1 and the rear wheel side left hydraulic cylinder 3. ..

Next, the left and right accumulator devices 25 provided in the middle of the right side passage 23 and the left side passage 24 will be described. Since the left and right accumulator devices 25 are similarly configured on the right side passage 23 side and the left side passage 24 side, the accumulator device 25 provided in connection with the right side passage 23 will be described below. The description of the accumulator device 25 provided by connecting to the left side passage 24 will be omitted.

The accumulator device 25 is provided so as to be connected to the first connecting pipe 5 on the front side and the second connecting pipe 12 on the rear side via the right side passage 23. Here, the accumulator device 25 includes a first pipeline 26 branched from the middle of the right side communication passage 23, a first accumulator 27 as a pressure accumulator provided connected to the first pipeline 26, and a first pipe. A damping valve 28 provided in the middle of the road 26, a second pipeline 29 branched from an intermediate portion of the first pipeline 26 between the damping valve 28 and the first accumulator 27, and the second pipeline 29. Two second accumulators 30 and 31 provided connected to the tip (downstream) side of the second accumulator and a second accumulator located in the middle of the second pipeline 29 located on the upstream side of the second accumulators 30 and 31. It is configured to include one control valve 32.

As shown in FIG. 2, the damping valve 28 controls the damping force of the pressure oil flowing in the first pipeline 26 toward the first accumulator 27, and generates a damping force that attenuates the flow from the right side communication passage 23. The inflow control valve 28A as a mechanism and the outflow that damps the flow from the first accumulator 27 by controlling the damping force of the pressure oil flowing from the first accumulator 27 toward the right side communication passage 23 in the first pipeline 26. A control valve 28B and an orifice 28C provided connected in parallel with the inflow control valve 28A and the outflow control valve 28B to limit the flow of pressure oil flowing in the first pipeline 26 to generate a damping force are included. It is composed of.

The damping valve 28 is configured as a valve device in which the inflow control valve 28A, the outflow control valve 28B, and the orifice 28C are connected in parallel to each other. Then, when the pressure oil flows from the outside into the first pipeline 26 between the right side communication passage 23 and the first accumulator 27, for example, the damping valve 28 flows into the orifice 28C and the pressure oil with respect to the pressure oil. A throttle resistance is given by the control valve 28A to generate a predetermined damping force. Further, when the pressure oil flows out from the first pipeline 26 (for example, the first accumulator 27) toward the right side communication passage 23, the orifice 28C and the outflow control valve 28B give the pressure oil a throttle resistance to give a predetermined damping. Generate force.

The first control valve 32 is composed of a normally closed type valve, in other words, a normally closed type solenoid valve, and always connects the second accumulators 30 and 31 to the upstream side of the second pipeline 29 (that is, the right side passage 23). It is held in a closed state so as to shut off the valve. However, when the first control valve 32 is excited by energization from the controller 43, which will be described later, pressure oil flows through the second pipeline 29 from the right side passage 23 toward the second accumulators 30 and 31. forgive. Therefore, while the first control valve 32 is open, the second accumulators 30 and 31 are in a state of communicating with the upstream side (that is, the right communication passage 23) of the second pipeline 29. The gas volume of the second accumulators 30 and 31 has a total gas capacity (volume) larger than that of the first accumulator 27 and has about twice the volume (volume) when the pressure is the same as that of the first accumulator 27. ing. In the present embodiment, the normally closed valve is used as the first control valve 32, but the normally open valve may be used and the valve may be closed by energizing when the roll rigidity is desired to be increased. However, since electric power is used in normal times, the power consumption is high. Therefore, it is preferable to use a normally closed type control valve for the first control valve 32.

The second pipeline 29 is provided with a bypass path 33 bypassing the first control valve 32, and the bypass path 33 is provided with a fixed orifice 34. In this fixed orifice 34, when a large pressure difference occurs in the second pipeline 29 before and after the first control valve 32, the pressure oil gradually flows from the higher pressure side to the lower pressure side through the bypass passage 33. Allow to be distributed to. The fixed orifice 34 has a sufficient flow path area of the fixed orifice 34, for example, in order to limit the flow of pressure oil (hydraulic fluid) generated in the connecting pipelines 5 and 12 due to the expansion and contraction operation (stroke) of the hydraulic cylinders 1 to 4. It is formed small in. When this flow path area is sufficiently small, the flow of the hydraulic fluid in the connecting pipeline generated by the stroke of the hydraulic cylinder is restricted to the extent that it does not affect the damping force generated by the damping valve 28 as the damping force generating mechanism. It is the size required to do so. That is, in relation to the damping valve 28, it means that it is not affected by the damping force and further does not affect the roll rigidity, and is within the error range.

Since the roll rigidity of the first accumulator 27 is high, the volume of the first accumulator 27 is very small, and the volume change in the pipeline (system) due to the load weight or the hydraulic pressure change cannot be tolerated. Therefore, the fixed orifice 34 is provided in the second accumulators 30 and 31 having a volume larger than that of the first accumulator 27, and the fixed orifice 34 has a volume against the volume change in the pipeline (system) due to the load weight and the change in the oil pressure. Functions as an orifice for change compensation. The fixed orifice 34 is configured by providing a plurality of holes having a diameter of 0.1 mm in series, for example, two holes.

The second accumulators 30 and 31 are accumulators for volume change compensation for compensating for the volume change of the hydraulic fluid due to, for example, the load weight of the vehicle and the temperature change (oil temperature change) of the hydraulic fluid, and the first control valve 32 is closed. Even at the time of valve, it is connected to the tip side of the second pipeline 29 and the bypass path 33 via a fixed orifice 34 for compensating for volume change, which has a sufficiently small flow path area.

When the first control valve 32 is closed, the fixed orifice 34 receives a transient flow of pressure oil (hydraulic fluid) due to a change in the posture of the vehicle body, vibration, etc., that is, a flow of pressure oil toward the second accumulators 30 and 31. It gives a large resistance and restricts the flow of pressure oil in this case. However, the fixed orifice 34 allows the flow of pressure oil toward the second accumulators 30 and 31 against the volume change in the pipeline (system) due to the load weight and the oil temperature change, and the orifice for volume change compensation. , Acts as an accumulator.

A relief valve 35 is provided in parallel with the first control valve 32 and the fixed orifice 34 in the middle of the bypass path 33. The relief valve 35 is opened, for example, when an excessive pressure is generated on the upstream side (that is, the right side passage 23) of the second pipeline 29, and the excess pressure at this time is directed toward the second accumulators 30 and 31. It is something that is missed (relieved). The relief valve 35 has a function of protecting the system by opening the valve when, for example, the internal pressure of the system rises excessively due to an excessive suspension input.

Further, the accumulator device 25 includes a third accumulator 36 connected in parallel with the first accumulator 27 and the second accumulators 30 and 31. The third accumulator 36 is connected to an intermediate portion of the first line 26 (for example, between the first accumulator 27 and the damping valve 28) via the third line 37. The capacity (volume) of the third accumulator 36 is equal to or larger than that of the first accumulator 27 or smaller than that of the second accumulators 30 and 31.

In the middle of the third pipeline 37, a normally closed type second control valve 38 is provided on the upstream side of the third accumulator 36. The second control valve 38 is composed of a normally closed type solenoid valve, and is normally held in a closed state so as to shut off the third accumulator 36 with respect to the first pipeline 26. However, when the second control valve 38 is excited by the energization from the controller 43 described later, the pressure oil in the first pipeline 26 is allowed to flow toward the third accumulator 36. Therefore, while the second control valve 38 is open, the third accumulator 36 is on the upstream side of the third line 37 (for example, between the first accumulator 27 and the damping valve 28, the first line 26 It will be in a state of communicating with the part in the middle of.

The first pipeline 26 is provided with, for example, a filter 39 and a shut valve 40 located between the first accumulator 27 and the damping valve 28. The shut valve 40 is used for lubrication into the system and oil removal work at the time of disassembly. The shut valve 40 serves as a lubrication port for the hydraulic fluid when the valve is opened, and can be injected from the outside toward the first pipeline 26 so as to fill the hydraulic fluid (pressure oil). The filter 39 filters foreign matter in the hydraulic fluid injected from the shut valve 40 toward the first pipeline 26 to purify the hydraulic fluid.

As shown in a perspective view in FIG. 4, the accumulator device 25 is configured to have a manifold structure, and the first accumulator 27 and the third accumulator 36 are arranged so as to be separated from each other in the direction of the X-axis, for example. Further, the second accumulators 30 and 31 are also arranged apart from each other in the direction of the X-axis. The second accumulators 30 and 31 are arranged apart from the first accumulator 27 and the third accumulator 36, for example, in the direction of the Y-axis.

The temperature sensor 41 and the pressure sensor 42 are connected and provided in the middle of the right side passage 23, for example. The temperature sensor 41 constitutes, for example, a temperature output means that detects the temperature of the pressure oil (hydraulic fluid) in the connecting pipelines 5 and 12 and outputs the temperature to the controller 43. The pressure sensor 42 uses the pressure in the right side passage 23 (that is, the connecting pipes 5 and 12) as the system pressure at a position close to the connection portion (branch position) between the first pipe 26 and the second pipe 29, for example. It constitutes a pressure output means that detects and outputs this system pressure to the controller 43.

In the middle of the left side communication passage 24, as in the right side communication passage 23, the first line 26, the first accumulator 27, the damping valve 28, the second line 29, the second accumulators 30, 31 and the first control valve 32. An accumulator device 25 including a bypass path 33, a fixed orifice 34, a relief valve 35, a third accumulator 36, a third pipeline 37, and a second control valve 38 is provided. Further, a temperature sensor 41 and a pressure sensor 42 are provided in the middle of the left side passage 24 as well as the right side passage 23.

The controller 43 shown in FIG. 3 is a control device configured by, for example, a microcomputer or the like, and switches and controls the bridge valves 18, 22 and the first and second control valves 32, 38 and the like. The input side of the controller 43 is connected to the temperature sensor 41, the pressure sensor 42, the roll rigidity selection switch 44, the steering angle sensor 45, the vehicle speed sensor 46, the lateral acceleration sensor 47, etc., and the output side is the bridge valves 18, 22 and the first and first. 2 It is connected to control valves 32, 38, etc. The controller 43 has a memory 43A including, for example, a ROM, a RAM, a non-volatile memory, or the like.

In the memory 43A of the controller 43, a processing program for performing switching control of the bridge valves 18 and 22 (see FIG. 7), a processing program for performing switching control of the first control valve 32 (see FIG. 8), and a processing program for performing switching control of the first control valve 32. A counter N, a timer for measuring the elapsed time T, and the like are stored. The controller 43 individually switches and controls the bridge valves 18, 22 and / or the first and second control valves 32, 38 according to the operating state of the vehicle in order to variably adjust the roll rigidity of the vehicle. For example, the controller 43 switches and controls the bridge valves 18 and 22 and / or the first and second control valves 32 and 38 based on the lateral acceleration (lateral G) according to the steering (steering) state when the vehicle turns. be able to.

The roll rigidity selection switch 44 is a mode selection switch manually operated by the driver (operator) of the vehicle, and has a high roll rigidity "Sport", a standard roll rigidity "Standard", and a low roll rigidity "Comfort". Select one of the modes. That is, the first and second control valves 32 and 38 are switched and opened and closed as described below by the driver (operator) of the vehicle operating the roll rigidity selection switch 44.

The first and second control valves 32 and 38 of the accumulator device 25 are both held in the closed state when, for example, the "Sport" mode is selected. When the "Standard" mode is selected by the roll rigidity selection switch 44, the first control valve 32 is held in the closed state, but the second control valve 38 is switched to the open state. When the "Comfort" mode is selected by the roll rigidity selection switch 44, both the first and second control valves 32 and 38 are switched to the valve open state.

As a result, in the "Sport" mode, the roll rigidity is set to a high value only by the first accumulator 27. In the "Standard" mode, the roll stiffness is set to a standard value by the first accumulator 27 and the third accumulator 36. On the other hand, in the "Comfort" mode, the roll rigidity is set to a low value by the first accumulator 27, the second accumulators 30, 31 and the third accumulator 36.

The characteristic lines 48 to 50 shown in FIG. 5 show the relationship between the displacement of the wheels (that is, the expansion and contraction of the hydraulic cylinders 1 to 4) and the accumulator pressure. Since the characteristic line 48 is in the "Sport" mode and the first and second control valves 32 and 38 are closed together, the change in the accumulator pressure with respect to the displacement of the wheel depends only on the first accumulator 27. Is getting bigger. The characteristic line 49 is the case of the “Standard” mode, in which the first control valve 32 is closed and the second control valve 38 is open. Therefore, the change in accumulator pressure with respect to the displacement of the wheel is smaller than the characteristic line 48 depending on the first accumulator 27 and the third accumulator 36.

On the other hand, the characteristic line 50 shows that both the first control valve 32 and the second control valve 38 are opened in the "Comfort" mode. Therefore, the pressure change in the system due to the expansion and contraction of the hydraulic cylinders 1 to 4 is absorbed by the first accumulator 27, the second accumulators 30, 31 and the third accumulator 36, and the change in the accumulator pressure with respect to the wheel displacement is characteristic. It is even smaller than line 49.

In other words, in the "Sport" mode, since the first and second control valves 32 and 38 are both closed, the gas volume of the accumulator device 25 depends only on the first accumulator 27 and is the volume shown in FIG. It becomes S1. As a result, the roll rigidity on the front wheel side is set to a large rigidity at the volume S1 as in the characteristic line 51, and the roll rigidity on the rear wheel side is also increased as in the characteristic line 52. In the "Standard" mode, since the second control valve 32 is opened, the gas volume of the accumulator device 25 becomes the volume S2 shown in FIG. 6 depending on the first accumulator 27 and the third accumulator 36. As a result, the roll rigidity on the front wheel side and the rear wheel side is set to the standard rigidity in the volume S2 as shown in the characteristic lines 51 and 52.

In the "Comfort" mode, the first and second control valves 32 and 38 are opened together, so that the gas volume of the accumulator device 25 is determined by the first accumulator 27, the second accumulators 30, 31 and the third accumulator 36. It is greatly enlarged to become the volume S3 shown in FIG. As a result, the roll rigidity on the front wheel side and the rear wheel side is set to a low rigidity at the volume S3 as shown in the characteristic lines 51 and 52.

The steering angle sensor 45 detects the operating angle of the steering handle (not shown) as the steering angle during the steering operation (turning operation) of the vehicle, and outputs the detection signal to the controller 43. The vehicle speed sensor 46 detects the traveling speed of the vehicle as the vehicle speed and outputs the detection signal to the controller 43. The lateral acceleration sensor 47 detects, for example, the lateral acceleration (lateral G) that acts when the vehicle is turning, and outputs the detection signal to the controller 43. The lateral acceleration (lateral G) of the vehicle can also be calculated by calculation based on the detection signals from the steering angle sensor 45, the vehicle speed sensor 46, and the like.

The suspension device according to the first embodiment has the above-described configuration, and its operation will be described next.

First, in the hydraulic cylinders 1 to 4, the upper end side (bottom side) of the cylinders 1A to 4A is attached to the vehicle body side, and the protruding end side of the piston rods 1C to 4C is attached to the wheel side. When the vehicle is running, if vibrations in the upward or downward direction occur due to unevenness of the road surface, or vibrations such as pitching or rolling occur, the piston rods 1C to 4C extend and contract from the cylinders 1A to 4A. The pistons 1B to 4B slide up and down in the cylinders 1A to 4A.

Therefore, the pressure oil flows in and out (circulates) between the right side communication passage 23 and the left side communication passage 24 and the left and right accumulator devices 25, and at this time, the damping valve 28 of each accumulator device 25 enters the inside. A damping force is generated by the throttle resistance against the circulating pressure oil to buffer the expansion and contraction operation of the hydraulic cylinders 1 to 4.

Here, the first to third accumulators 27, 30, 31, and 36 of the accumulator device 25 are mode-selected by manual operation of the roll rigidity selection switch 44. When the driver (operator) of the vehicle selects, for example, the "Sport" mode, the gas volume of the accumulator device 25 becomes the volume S1 shown in FIG. 6, and the roll rigidity (characteristic line 51) on the front wheel side and the rear wheel The roll rigidity (characteristic line 52) on the side can be set to a large value.

When the "Standard" mode is selected, the gas volume of the accumulator device 25 becomes the volume S2 shown in FIG. 6, and the roll rigidity on the front wheel side and the rear wheel side can be set to the standard rigidity. On the other hand, when the "Comfort" mode is selected, the gas volume of the accumulator device 25 becomes the volume S3 shown in FIG. 6, and the roll rigidity on the front wheel side and the rear wheel side is low at the volume S3 as shown in the characteristic lines 51 and 52. It can be set to rigidity.

Next, the switching control process of the bridge valves 18 and 22 by the controller 43 will be described with reference to FIG. 7.

When the processing operation of FIG. 7 starts, it is determined in step 1 whether or not the “Sport” mode is selected by the roll rigidity selection switch 44. If "YES" is determined in step 1, it is determined in the next step 2 whether or not the vehicle speed is speed V1 or less. If "YES" is determined in step 2, it is determined in the next step 3 whether or not the steering angle is the angle θ1 or less. If "NO" is determined in step 3, the counter N is reset to zero (N = 0) in the next step 4, and the process returns to step 1.

If "YES" is determined in step 3, it is determined in the next step 5 whether or not the steering angular velocity, which is a differential value of the steering angle, is equal to or less than the angular velocity ω1. If "YES" is determined in step 5, it is determined in the next step 6 whether or not the lateral G acting on the vehicle is acceleration G1 or less. When it is determined as "NO" in steps 5 and 6, the counter N is reset to zero (N = 0) in step 4 and the process returns to step 1.

However, when it is determined as "YES" in step 6, it can be determined that the vehicle is substantially traveling straight because the steering angle and steering angular velocity of the vehicle are small and the lateral G is also small. Therefore, in the next step 7, the counter N is stepped by 1 (N = N + 1). In the next step 8, the time Δt of the program cycle is integrated with the counter N, and the elapsed time T is calculated as T = N × Δt. In the next step 9, it is determined whether or not the elapsed time T is equal to or greater than the determination time threshold value T0.

When it is determined as "NO" in step 9, the process returns to step 1 and the subsequent processing is continued. However, if it is determined as "YES" in step 9, it can be determined that the vehicle is traveling substantially straight over the determination time threshold value T0 or more. In this case, the roll rigidity is not necessarily large as in the "Sport" mode. No need to set the value. Therefore, in the next step 10, the bridge valves 18 and 22 are opened for a predetermined time, and the bridge valves 18 and 22 are returned in the next step 11.

That is, the bridge valves 18 and 22 are switched from the valve closing position (a) to the valve opening position (b) by energization from the controller 43 when the vehicle is traveling straight. As a result, the bridge valve 18 allows the pressure oil to flow between the first and second connecting pipes 5 and 6 through the front connecting line 17. Therefore, the hydraulic cylinders 1 and 2 on the front wheel side are in a state where the upper chamber A and the lower chamber B communicate with each other. Further, even on the rear wheel side, the first and second connecting pipelines 11 and 12 are in a communicating state via the rear connecting path 21 and the bridge valve 22. As a result, the upper chamber A and the lower chamber B of the hydraulic cylinders 1 to 4 of each wheel communicate with each other, so that each wheel independently receives an input from the road surface and smoothly moves up and down with a small resistance. It moves and gives a good ride.

Further, when it is determined as "NO" in the step 2, it is determined in the next step 12 whether or not the vehicle speed is speed V2 (however, V2> V1) or less. When it is determined as "NO" in step 12, it can be determined that the vehicle is traveling at a relatively high speed exceeding the speed V2. When the vehicle is traveling at high speed, for example, if the roll rigidity is sharply lowered, the steering stability may be adversely affected. Therefore, for example, the bridge valves 18 and 22 are set to the valve closing position (a), and the process returns to step 1. ..

When it is determined as "YES" in step 12, it is determined whether or not the steering angle is the angle θ2 (however, θ2 <θ1) or less by the next step 13 under the condition that the vehicle speed is faster than the speed V1 and the speed is V2 or less. do. When the steering angle exceeds the angle θ2, if the roll rigidity is lowered by the amount that the vehicle speed is increased, the steering stability may be adversely affected. Therefore, if "NO" is determined in step 13, the counter N is reset to zero (N = 0) in the next step 14, and the process returns to step 1.

If "YES" is determined in step 13, it is determined in the next step 15 whether or not the steering angular velocity is equal to or less than the angular velocity ω2 (however, ω2 <ω1). If "YES" is determined in step 15, it is determined in the next step 16 whether or not the lateral G acting on the vehicle is acceleration G2 (however, G2 <G1) or less. If "NO" is determined in steps 15 and 16, lowering the roll rigidity may adversely affect steering stability, so in each case, the counter N is reset to zero (N = 0) in step 14. , Return to the process of step 1.

However, when it is determined as "YES" in step 16, the steering angle and the steering angular velocity of the vehicle are equal to or less than the respective threshold values (angle θ2, angular velocity ω2), and the lateral G is also equal to or less than the threshold acceleration G2. Can be judged to be traveling substantially straight. Therefore, by the processes of steps 7 to 9, it is determined whether or not the vehicle is substantially traveling straight over the determination time threshold value T0 or more, and in step 10, the bridge valves 18 and 22 are opened for a predetermined time. The process is performed, and the process returns in the next step 11.

On the other hand, when it is determined as "NO" in step 1, the "Standard" mode or the "Comfort" mode is selected by the roll rigidity selection switch 44. In this case, the counter N is reset to zero (N = 0) in the next step 17, and returns in the next step 18. When the "Standard" mode or the "Comfort" mode is selected, the appropriate vehicle speed, steering angle, angular velocity and lateral G threshold value are set separately, and the switching control process of the bridge valves 18 and 22 is performed. It may be configured to be performed.

Next, the valve opening control process of the first control valve 32 by the controller 43 will be described with reference to FIG. In the process of FIG. 8, it is assumed that the bridge valves 18 and 22 and the first control valve 32 are in the closed state in advance.

When the processing operation of FIG. 8 starts, it is determined in step 21 whether or not the detected temperature (oil temperature) of the temperature sensor 41 is equal to or higher than the threshold temperature t1. If it is determined as "NO" in step 21, it can be determined that the oil temperature in the system (for example, the communication passage 23) is in the normal temperature range, so the process returns to step 21. In this state, the bridge valves 18 and 22 and the first control valve 32 are in the closed state.

If "YES" is determined in step 21, the system pressure Pt is calculated from the oil temperature according to step 21 in step 22. In the next step 23, whether or not the detected value Ps of the system pressure detected by the pressure sensor 42 has risen to the total value (Pt + α) or more of the calculated value (system pressure Pt) and the system pressure adjustment margin value α. Is determined as (Ps ≧ Pt + α).

When it is determined as "NO" in step 23, it can be determined that the detected value Ps of the system pressure is in the normal range. Therefore, in the next step 24, the counter N is reset to zero (N = 0), and the processing after step 21 is performed. Return to. However, if "YES" is determined in step 23, the oil temperature in the system becomes high, and the detected value Ps of the system pressure also rises to the total value (Pt + α) or more. Therefore, in the next step 25, the vehicle speed Determines whether or not the speed is V1 or less. If "YES" is determined in step 25, it is determined in the next step 26 whether or not the steering angle is the angle θ1 or less. If "NO" is determined in step 26, the counter N is reset to zero (N = 0) in step 24, and the process returns to the processes after step 21.

If "YES" is determined in step 26, it is determined in the next step 27 whether or not the steering angular velocity is equal to or less than the angular velocity ω1. If it is determined as "NO" in step 27, the counter N is reset to zero (N = 0) in step 24, and the process returns to the process after step 21. Therefore, both the bridge valves 18 and 22 and the first control valve 32 are placed in the closed state, and the roll rigidity of the hydraulic cylinders 1 to 4 can be increased.

However, when it is determined as "YES" in step 27, the vehicle speed, steering angle, and steering angular velocity are equal to or less than the respective threshold values (speed V1, angle θ1, angular velocity ω1), so that the vehicle travels substantially straight. , Or it can be determined that the vehicle is in a running state close to straight ahead, and it is not always necessary to increase the roll rigidity. Therefore, in the next step 28, the counter N is stepped by 1 (N = N + 1). In the next step 29, the time Δt of the program cycle is integrated with the counter N, and the elapsed time T is calculated as T = N × Δt. In the next step 30, it is determined whether or not the elapsed time T is equal to or greater than the determination time threshold value T0.

When it is determined as "NO" in step 30, the process returns to step 21 and the subsequent processing is continued. However, when it is determined as "YES" in step 30, it is determined that the vehicle is substantially straight or nearly straight ahead over the judgment time threshold value T0 or more in the state where the system pressure is rising as described above. can. Therefore, in the next step 31, it is determined whether or not the bridge valves 18 and 22 are open. If it is determined as "YES" in step 31, the bridge valves 18 and 22 are opened so as to reduce the roll rigidity. Therefore, in the next step 32, the first control valve 32 is opened for a predetermined time. And return in the next step 33.

On the other hand, when it is determined as "NO" in the step 25, it is determined in the next step 34 whether or not the vehicle speed is speed V2 (however, V2> V1) or less. When it is determined as "NO" in step 34, it can be determined that the vehicle is traveling at a relatively high speed exceeding the speed V2. When the vehicle is traveling at high speed, for example, if the roll rigidity is sharply lowered, the steering stability may be adversely affected. Therefore, for example, the bridge valves 18 and 22 are set to the valve closing position (a), and the process returns to step 21. ..

When it is determined as "YES" in step 34, it is determined whether or not the steering angle is the angle θ2 (however, θ2 <θ1) or less by the next step 35 under the condition that the vehicle speed is faster than the speed V1 and the speed is V2 or less. do. When it is determined as "NO" in step 35, if the steering angle exceeds the angle θ2, the steering stability may be adversely affected if the vehicle speed is increased, for example, if the roll rigidity is lowered. In the next step 36, the counter N is reset to zero (N = 0), and the process returns to the process of step 21.

If "YES" is determined in step 35, it is determined in the next step 37 whether or not the steering angular velocity is equal to or less than the angular velocity ω2 (however, ω2 <ω1). Even if it is determined as "NO" in step 37, if the roll rigidity is suddenly lowered by the amount that the steering angular velocity is increased, the steering stability may be adversely affected. Therefore, the counter N is set in step 36. The process is reset to zero (N = 0), and the process returns to step 21.

However, when it is determined as "YES" in step 37, the steering angle and the steering angular velocity of the vehicle are equal to or less than the respective threshold values (angle θ2, angular velocity ω2), so that the vehicle is substantially straight or nearly straight. It can be judged that there is no possibility that the steering stability will be adversely affected even if the roll rigidity is suddenly lowered. Therefore, it is determined whether or not the elapsed time T has reached the determination time threshold value T0 or more by the processing of steps 28 to 30.

When it is determined as "YES" in step 30, it can be determined that the vehicle is substantially straight or nearly straight ahead over the determination time threshold value T0 or more in the state where the system pressure is rising as described above. Therefore, in the next step 31, it is determined whether or not the bridge valves 18 and 22 are open. If it is determined as "YES" in step 31, the bridge valves 18 and 22 are opened so as to reduce the roll rigidity. Therefore, in the next step 32, the first control valve 32 is opened for a predetermined time. And return in the next step 33.

When the first control valve 32 is opened in the process of step 32, the second accumulators 30 and 31 are in a state of communicating with the upstream side (that is, the right communication passage 23) of the second pipeline 29. Therefore, the pressure change in the system due to the expansion and contraction of the hydraulic cylinders 1 to 4 is absorbed by the first accumulator 27 and the second accumulators 30 and 31.

Moreover, when it is determined in step 23 that the detected value Ps of the system pressure has risen to the total value (Pt + α) or more of the system pressure Pt and the system pressure adjustment margin value α (Ps ≧ Pt + α), that is, abruptly. When the detected value Ps of the system pressure becomes high due to the temperature rise, the change of the system pressure is changed to the first accumulator 27 and the second accumulators 30 and 31 by opening the first control valve 32 in the process of step 32. Can be absorbed by.

Therefore, the change in the internal pressure in the system can be leveled by the second accumulators 30 and 31, and the change in the internal pressure in the system due to the sudden temperature change (oil temperature rise) can be corrected by the process of step 32 in the first control valve 32. By opening the valve, the second accumulators 30 and 31 can absorb the oil, and the system internal pressure compensation can be realized. Further, against a gradual temperature change (pressure rise), the fixed orifice 34 allows the flow of pressure oil toward the second accumulators 30 and 31 even when the first control valve 32 is closed, and the internal pressure of the system is increased. Can be compensated.

Further, a relief valve 35 is provided in parallel with the first control valve 32 and the fixed orifice 34 in the middle of the bypass path 33. For example, when an excessive pressure is generated on the upstream side (right side passage 23) of the second pipeline 29, the relief valve 35 is opened to prevent the system internal pressure from rising excessively due to an excessive suspension input. It is possible to protect the suspension device (that is, the passive roll control system).

The pressure compensation control in the system for the temperature rise described above should not be performed at a high vehicle speed in which the traveling speed of the vehicle exceeds a predetermined value. Also, do not perform the bridge valves 18 and 22 even when they are in the closed state. Further, when the vehicle is steered, it is preferable that the pressure compensation control for the temperature rise is performed only at the time of the minute steering when the steering angles are θ1 and θ2 or less. The steering thresholds of the steering angles θ1 and θ2 are changed according to the vehicle speed, the thresholds are lowered at high speeds, and the first control valve 32 is inadvertently opened to prevent the steering stability from being lowered.

Thus, according to the first embodiment, the suspension device provided with the passive roll control system is electronically controlled, and between the two hydraulic lines (for example, the first and second connecting pipes 5 and 6). In addition to the bridge valves 18 and 22 that communicate and shut off, a plurality of accumulators 27, 30, 31, and 36 are arranged in the accumulator device 25, and the second and third accumulators are arranged by the first and second control valves 32 and 38. The 30th, 31st, and 36th are selectively communicated with and cut off from the 1st, 2nd, and 3rd pipelines 26, 29, and 37. Therefore, the roll rigidity of the bridge valves 18 and 22 when closed can be switched in multiple stages by a plurality of accumulators 27, 30, 31 and 36, and for example, the roll rigidity mode can be switched.

Moreover, the change in the system internal pressure due to the sudden temperature change (oil temperature rise) can be absorbed by the second accumulators 30 and 31 by opening the first control valve 32, for example, and the system internal pressure compensation can be realized. Further, against a gradual temperature change (pressure rise), the fixed orifice 34 allows the flow of pressure oil toward the second accumulators 30 and 31 even when the first control valve 32 is closed, and the internal pressure of the system is increased. Can be compensated. Further, when an excessive pressure is generated on the upstream side (right side passage 23) of the second pipeline 29, the relief valve 35 is opened to prevent the system internal pressure from rising excessively due to an excessive suspension input. This makes it possible to protect the suspension device (that is, the passive roll control system).

Further, since the bridge valves 18 and 22 and the first and second control valves 32 and 38 are composed of normally closed solenoid valves, for example, in the event of a system failure (power failure), the bridge valves 18 and 22 and the first and second control valves 32 and 38 are used. The first and second control valves 32 and 38 are held in the closed state, a large roll rigidity can be obtained, and high steering stability can be ensured.

On the other hand, when the controller 43 can be energized, the bridge valves 18 and 22 can be opened when the vehicle goes straight, and by communicating the two hydraulic lines, the four-wheel suspension operates independently with respect to the road surface input. It is possible to improve the riding comfort. Moreover, by selectively opening and closing the first and second control valves 32 and 38, the roll rigidity of the accumulator device 25 can be variably switched in multiple stages, and the riding comfort of the vehicle can be improved. Further, since the fixed orifice 34 is provided in the accumulator device 25 as a compensation mechanism for a gradual temperature change (pressure rise), it is not necessary to separately provide a compensation mechanism. Further, since the fixed orifice 34 has a sufficiently small size, the flow of pressure oil can be allowed only when necessary without affecting the roll rigidity.

Next, FIG. 9 shows a second embodiment of the present invention. The feature of the second embodiment is that the second control valve of the accumulator device is composed of a normally open type (normally open type) solenoid valve. In the second embodiment, the same components as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

The accumulator device 61 adopted in the second embodiment is the same as the accumulator device 25 described in the first embodiment, that is, the first line 26, the first accumulator 27, the damping valve 28, and the second line 29. , Second accumulators 30, 31, first control valve 32, bypass path 33, fixed orifice 34, relief valve 35, third accumulator 36, third line 37, filter 39, shut valve 40, and the like. There is.

However, the accumulator device 61 in this case is provided with a normally open type second control valve 62 located in the middle of the third pipeline 37 and on the upstream side of the third accumulator 36. That is, the second control valve 62 is composed of a normally open type (normally open type) solenoid valve, and is always held in an open state so as to communicate the third accumulator 36 with the first pipeline 26. .. That is, the second control valve 62 opens when the energization from the controller 43 is stopped and degaussed, and the third accumulator 36 is on the upstream side of the third pipeline 37 (for example, the first accumulator 27 and the damping valve). It is in a state of communicating with 28 (in the middle of the first pipeline 26).

On the other hand, when the second control valve 62 is excited by the energization from the controller 43, the second control valve 62 is switched to the valve closing position, and the pressure oil in the first pipeline 26 is blocked from flowing toward the third accumulator 36. Therefore, when the second control valve 62 is closed, the third accumulator 36 is shut off from the upstream of the third pipeline 37 (that is, the first pipeline 26), and the operation as an accumulator is prohibited. ..

Thus, in the second embodiment configured as described above, the roll rigidity at the time of closing the bridge valve 18, for example, can be switched in multiple stages by the plurality of accumulators 27, 30, 31, 36. It is possible to obtain the same effect as that of the first embodiment. In particular, in the second embodiment, the second control valve 62 is composed of a normally open solenoid valve.

As a result, in the event of a system failure such as a power failure, the second control valve 62 is opened and the third accumulator 36 is maintained in a state of communicating with the first pipeline 26. Therefore, the roll rigidity of the accumulator device 61 is set in the same manner as in the above-mentioned "Standard" mode, and the gas volume of the accumulator device 61 depends on the first accumulator 27 and the third accumulator 36, and the volume shown in FIG. It becomes S2, and the roll rigidity on the front wheel side and the rear wheel side can be set to the standard rigidity.

As a result, the risk of vehicle overturning due to excessive roll rigidity can be reduced (for example, the risk of overturning can be reduced when the inner ring side gets over a large protrusion while turning the vehicle, or when sudden steering to avoid danger, etc.). It is possible to ensure safety in the event of a fall. Further, since the gas volume of the accumulator device 61 can be increased to some extent by the first accumulator 27 and the third accumulator 36, deterioration of riding comfort due to excessive spring constant and roll rigidity can be reduced.

When the system fails, the bridge valves 18 and 22 also return to the closed position (a), so the riding comfort tends to deteriorate even when going straight, but the gas volume of the accumulator device 61 can be increased to some extent. Deterioration of riding comfort can be reduced. Moreover, during system control, the roll rigidity of the accumulator device 61 is most frequently used in the "Standard" mode, during which the first and second control valves 32 and 62 are both degaussed, eliminating the need to energize the solenoid. Power consumption can be reduced.

In each of the above embodiments, for example, a case where the oil temperature in the first and second connecting pipes 5 and 6 is detected by the temperature sensor 41 has been described as an example. However, the present invention is not limited to this, and for example, a temperature output means that estimates and outputs the oil temperature in the first and second connecting pipelines from the running state of the vehicle, the ambient temperature, and the like may be used. ..

Further, in the first embodiment, the case where the accumulator device 25 is composed of the first, second, and third accumulators 27, 30, 31, and 36 has been described as an example. However, the present invention is not limited to this, and an accumulator device may be configured by using, for example, two accumulators or four or more accumulators.

The first accumulator is not limited to the first accumulator 27 shown in FIG. 2, for example, and the third accumulator 36 may be configured as the first accumulator. In this case, it is also possible to abolish the first accumulator 27 shown in FIG. 2 and configure the accumulator device.

Further, in each of the above-described embodiments, the case where the piston rods 1C to 4C project downward from the cylinders 1A to 4A of the hydraulic cylinders 1 to 4 has been described as an example. However, the suspension device of the present invention is not limited to this, and for example, the piston rod of each hydraulic cylinder may be configured to protrude upward from the cylinder.

Further, in each of the above-described embodiments, the pistons 1B to 4B are provided in the cylinders 1A to 4A of the hydraulic cylinders 1 to 4, and the cylinders 1A to 4A are divided into two upper and lower chambers (upper chamber A and lower chamber B). The case of imaging has been described as an example. However, the present invention is not limited to the one shown in the drawing. For example, a throttle is provided in each of the pistons 1B to 4B, and the pressure oil (liquid) flowing between the upper chamber A and the lower chamber B through the throttle is used. It may be configured to generate a damping force.

Next, as the suspension device included in the above embodiment, for example, the suspension device described below can be considered.

In the first aspect, a left and right hydraulic accumulator, which is interposed between the left and right wheels and the vehicle body, and the inside of the cylinder is defined as an upper chamber and a lower chamber by a piston, and the left. ， Between the right hydraulic cylinders, the upper chamber of one hydraulic cylinder communicates with the lower chamber of the other hydraulic cylinder, and the upper chamber of the other hydraulic cylinder communicates with the lower chamber of the one hydraulic cylinder. The first and second connecting pipelines connected by a cross and at least one of the first and second connecting pipelines are connected to each other via a damping force generating mechanism. A suspension device including an accumulator device, wherein the accumulator device includes a first accumulator, a second accumulator connected in parallel with the first accumulator, and a first accumulator provided on the upstream side of the second accumulator. It has a control valve and a fixed orifice located between the connecting pipeline and the second accumulator and provided in parallel with the first control valve, and the flow path area of the fixed orifice is the hydraulic pressure. It is characterized in that it is sufficiently small in order to limit the flow of the hydraulic fluid in the connecting pipeline generated by the stroke of the cylinder to such an extent that it does not affect the damping force generated by the damping force generating mechanism.

As a second aspect of the suspension device, in the first aspect, the first control valve is a normally closed type control valve. As a third aspect of the suspension suspension device, in any one of the first to second aspects, the gas volume of the second accumulator is such that the pressures of the first accumulator and the second accumulator are the same. The first accumulator is larger than the first accumulator. As a fourth aspect of the suspension device, in any one of the first to third aspects, a third accumulator connected in parallel with the first and second accumulators is further provided, and the third accumulator is provided. A normally closed type second control valve is provided on the upstream side. As a fifth aspect of the suspension device, in any one of the first to third aspects, a third accumulator connected in parallel with the first and second accumulators is further provided, and the third accumulator is provided. It is characterized in that a normally open type second control valve is provided on the upstream side.

As a sixth aspect of the suspension device, in any one of the first to fifth aspects, the temperature output means for outputting the temperature in the connecting pipeline is provided, and the temperature by the temperature output means is predetermined. When the temperature is exceeded and the vehicle speed, steering angle, and steering angular velocity of the vehicle are below the threshold value, or when the lateral acceleration of the vehicle is below the threshold value for a predetermined time or longer, the first control valve is turned on. It is characterized by opening the valve. As a seventh aspect of the suspension device, in the sixth aspect, when the bridge valve that communicates with and shuts off the first and second connecting pipelines is in the valve open state, the first control valve is in the valve open state. It is characterized by doing.

As an eighth aspect of the suspension device, in any one of the first to seventh aspects, a relief valve is provided in parallel with the fixed orifice. A ninth aspect of the suspension device is characterized in that, in any one of the first to eighth aspects, the opening and closing of the control valve is switched by an operator's switch operation.

1,2,3,4 Hydraulic cylinder (hydraulic cylinder)
1A, 2A, 3A, 4A Cylinder 1B, 2B, 3B, 4B Piston 5,11 First connecting line 6,12 Second connecting line 17 Front connecting line 18, 22 Bridge valve 21 Rear connecting line 23, 24 consecutive passages 25, 61 accumulator device 27 1st accumulator 28 damping valve 30, 31 2nd accumulator 32 1st control valve 34 fixed orifice 35 relief valve 36 3rd accumulator 38, 62 2nd control valve 41 Temperature sensor (temperature output means) )
43 Controller 44 Roll stiffness selection switch A Upper chamber B Lower chamber

Claims (9)

The left and right hydraulic cylinders, which are interposed between the left and right wheels and the vehicle body, and the inside of the cylinder is defined by the piston into the upper chamber and the lower chamber, respectively.
Between the left and right hydraulic cylinders, the upper chamber of one hydraulic cylinder communicates with the lower chamber of the other hydraulic cylinder, and the upper chamber of the other hydraulic cylinder is the lower chamber of the one hydraulic cylinder. The first and second connecting pipelines, which are connected by a cross so as to communicate with
An accumulator device provided by connecting to at least one of the first and second connecting pipes via a damping force generating mechanism.
Suspension device with
The accumulator device is
With the first accumulator
A second accumulator connected in parallel with the first accumulator,
The first control valve provided on the upstream side of the second accumulator and
A fixed orifice located between the connecting line and the second accumulator and provided in parallel with the first control valve,
Have,
The flow path area of the fixed orifice limits the flow of the hydraulic fluid in the connecting pipeline generated by the stroke of the hydraulic cylinder to such an extent that it does not affect the damping force generated by the damping force generating mechanism. A suspension device characterized by being sufficiently small. The suspension device according to claim 1, wherein the first control valve is a normally closed type control valve. The suspension according to claim 1 or 2, wherein the gas volume of the second accumulator is larger than that of the first accumulator when the pressures of the first accumulator and the second accumulator are the same. Device. A third accumulator connected in parallel with the first and second accumulators is further provided.
The suspension device according to any one of claims 1 to 3, wherein a normally closed type second control valve is provided on the upstream side of the third accumulator. A third accumulator connected in parallel with the first and second accumulators is further provided.
The suspension device according to any one of claims 1 to 3, wherein a normally open type second control valve is provided on the upstream side of the third accumulator. It has a temperature output means for outputting the temperature in the connection pipeline.
When the temperature of the temperature output means exceeds a predetermined temperature, and the vehicle speed, steering angle, and steering angular velocity of the vehicle are below the threshold value, or the lateral acceleration of the vehicle is below the threshold value, the state continues for a predetermined time or longer. The suspension device according to any one of claims 1 to 5, wherein the first control valve is sometimes opened. The suspension device according to claim 6, wherein the first control valve is opened when the bridge valve that communicates with and shuts off the first and second connecting pipes is opened. The suspension device according to any one of claims 1 to 7, wherein a relief valve is provided in parallel with the fixed orifice. The suspension device according to any one of claims 1 to 8, wherein the control valve is opened and closed by operating a switch of an operator.

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