JP2006213119A - Suspension device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suspension device for a vehicle capable of certainly controlling a vehicle posture without causing enlargement of the device and increase of power loss. <P>SOLUTION: Elevation adjusting mechanisms 14A, 14B by hydraulic pressure are provided on an upper spring sheet 5 of suspension units 1A, 1B, and both of the elevation adjusting mechanisms 14A, 14B are connected to a hydraulic circuit 2 furnished with a first hydraulic pump 16 and a second hydraulic pump 17 driven by a common motor 15. A first passage 19 to supply hydraulic fluid to the elevation adjusting mechanism 14B from the elevation adjusting mechanism 14A by the first hydraulic pump 16 and a second passage 20 to supply hydraulic fluid to the elevation adjusting mechanism 14A from the elevation adjusting mechanism 14B by the second hydraulic pump 17 are provided in the hydraulic circuit 2. The passages 19, 20 to connect both of the elevation adjusting mechanisms 14A, 14B to each other are properly changed over to each other by first and second channel change-over valves 23, 24. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle suspension device capable of controlling the attitude of a vehicle.

As a vehicle suspension device, one having an attitude control function has been developed. In this vehicle suspension apparatus, actuators that can be adjusted up and down by hydraulic pressure are respectively provided in the left and right suspension units of the vehicle, and the left and right actuators of the vehicle are controlled according to the driving state of the vehicle such as rolling. Specifically, for example, when rolling, the hydraulic oil is supplied to the actuator on the side where the vehicle body is going to sink, and the hydraulic oil of the actuator on the side where the vehicle body is about to rise is discharged, so that the vehicle posture is stably maintained. It is supposed to be.
JP 2002-542977 gazette

  However, in the case of this conventional suspension device, during the attitude control, the hydraulic oil in the reservoir tank is supplied to one actuator by a hydraulic pump, and the hydraulic oil in the other actuator is returned to the reservoir tank. For this reason, the hydraulic pump must generate all the operating force of the actuator that lifts the vehicle, and the flow of hydraulic oil that is returned from the reverse actuator to the reservoir tank is wasted. For this reason, the pump capacity of the hydraulic pump has to be increased, and there is a concern that the size of the apparatus may increase and the power loss of the drive source may increase.

  Accordingly, the present invention is intended to provide a vehicle suspension device that can reliably control the vehicle posture without increasing the size of the device and increasing the power loss.

  In order to achieve the above object, the invention according to claim 1 is directed to a suspension unit (for example, suspension units 1A and 1B in an embodiment described later) that forms a pair of the left and right sides of the vehicle body and the front and rear. A coil spring (for example, a coil spring 3 in an embodiment described later) to be connected to the vehicle, an upper spring seat (for example, an upper spring seat 5 in an embodiment described later) for supporting the upper end of the coil spring on the vehicle body side, And a lower spring seat that supports the lower end of the coil spring on the wheel side (for example, a lower spring seat 6 in an embodiment described later), an upper spring seat of each suspension unit At least the lower spring seat One of the displacements is provided with a hydraulic lift adjustment mechanism (for example, a first lift adjustment mechanism 14A and a second lift adjustment mechanism 14B in an embodiment to be described later), and the lift adjustment mechanism of the suspension unit that forms a pair is used as a common motor (for example, The first hydraulic pump (for example, the first hydraulic pump 16 in the embodiment described later) and the second hydraulic pump (for example, the second hydraulic pump in the embodiment described later) driven by the motor 15 in the embodiment described later. Connected to a hydraulic circuit (for example, a hydraulic circuit 2 in an embodiment described later) provided with a hydraulic pump 17), and this hydraulic circuit is operated in the lifting adjustment mechanism of one suspension unit by the operation of the first hydraulic pump. A first passage for supplying oil to the lifting and lowering adjustment mechanism of the other suspension unit, and the other by the operation of the second hydraulic pump. A second passage for supplying hydraulic oil in the lift adjustment mechanism of the suspension unit to the lift adjustment mechanism of one suspension unit, and connection switching between the first passage and the second passage to both the lift adjustment mechanisms are possible. A flow path switching valve (for example, first and second flow path switching valves 23 and 24 in an embodiment described later) is provided, and the flow path switching valve is controlled according to the running state of the vehicle.

  In the case of this invention, when controlling the attitude of the vehicle, the first hydraulic pump and the second hydraulic pump are driven by a common motor, and the flow path switching valve is selectively operated according to the traveling state of the vehicle. When the flow path switching valve connects one of the first passage and the second passage to both the lift adjustment mechanisms, the hydraulic oil in one of the lift adjustment mechanisms is moved to the other side by the action of the hydraulic pump in the passage. Supplied to the lift adjustment mechanism.

  According to a second aspect of the present invention, there is provided a reservoir tank (for example, a reservoir tank 28 in an embodiment described later) on the pump suction side of the first passage and the second passage. Are provided with branch passages (for example, branch passages 25 and 26 in embodiments described later) and an opening / closing valve (for example, an opening / closing valve 27 in embodiments described later) for opening and closing the branch passages.

  In this case, when the branch passage is opened by the opening / closing valve, the pump suction side of the first passage and the second passage is connected to the reservoir tank. For this reason, the hydraulic oil sucked from the reservoir tank is supplied to both the lift adjustment mechanisms by the operation of the first hydraulic pump and the second hydraulic pump, or the hydraulic oil in both the lift adjustment mechanisms is discharged to the reservoir tank. Is possible.

According to the first aspect of the present invention, the hydraulic oil in the lift adjustment mechanism on one side is supplied to the lift adjustment mechanism on the other side by either the first hydraulic pump or the second hydraulic pump, thereby Since posture control is performed, reliable posture control can be performed with small power of the hydraulic pump. That is, the first or second hydraulic pump only needs to perform pump operation in the form of adding pump power to the pressure in the suction-side lift adjustment mechanism. Can be supplied.
Therefore, according to the present invention, reliable posture control can be realized while suppressing the enlargement of the apparatus and the power loss of the motor.
Further, in the case of the present invention, when controlling the attitude of the vehicle, by switching the first passage and the second passage by the flow passage switching valve while operating the first pump and the second pump with a common motor, Since the raising / lowering operation of the paired vehicle height adjusting devices can be switched, there is an advantage that the operation responsiveness is good and quick attitude control according to the driving state is possible.

  According to the invention described in claim 2, the vehicle height adjustment function can be provided by a slight improvement of the hydraulic circuit.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
1 to 4 are configuration diagrams showing an embodiment in which a vehicle suspension device (hereinafter referred to as “suspension device”) according to the present invention is applied to a front wheel side of a vehicle. The suspension device of this embodiment includes a pair of suspension units 1A and 1B that suspend a vehicle body on left and right front wheels (not shown), and a hydraulic circuit 2 that controls these suspension units 1A and 1B.

  Each of the suspension units 1A and 1B includes a coil spring 3 that absorbs vibration and shock between the vehicle body and the wheel, and a shock absorber 4 that generates a damping force due to oil flow resistance. It is supported on the vehicle body side and the wheel side via the spring seat 5 and the lower spring seat 6, respectively. The shock absorber 4 includes a cylinder tube 7 filled with oil, and a piston rod 8 inserted and fitted to the cylinder tube 7 so as to be able to advance and retract. The lower end of the cylinder tube 7 is disposed on the wheel side via a suspension arm (not shown). In addition, the upper end of the piston rod 8 is coupled to the vehicle body side together with the upper spring seat 5. The coil spring 3 is disposed on the outer peripheral side of the shock absorber 4, and the lower spring seat 6 is coupled to the outer peripheral surface of the cylinder tube 7 and is supported on the wheel side via the cylinder tube 7.

  The upper spring seat 5 has an annular cylinder hole 9 a and a base member 9 that is directly fixed to the vehicle body side together with the piston rod 8. The upper spring seat 5 is slidably fitted into the cylinder hole 9 a of the base member 9. An annular piston 11 that forms a working chamber 10 between the base body 9 and a seat body 13 that is coupled to the annular piston 11 via a connecting wall 12 and directly supports the upper end of the coil spring 3. The annular piston 11 constitutes a hydraulic lift adjustment mechanism 14A (14B). Hereinafter, the lift adjustment mechanism of the suspension unit 1A on the left side in the figure is referred to as a first lift adjustment mechanism 14A, and the lift adjustment mechanism of the suspension unit 1B on the right side in the figure is referred to as a second lift adjustment mechanism 14B.

  The hydraulic circuit 4 includes a first hydraulic pump 16 and a second hydraulic pump 17 that are driven by a common motor 15. In this embodiment, the first hydraulic pump 16 and the second hydraulic pump 17 are constituted by plunger pumps. The hydraulic circuit 4 includes a first passage 19 and a second passage 20 which are two passages connecting the supply / discharge ports 18A and 18B of the first elevation adjustment mechanism 14A and the second elevation adjustment mechanism 14B. It is provided in parallel. The first hydraulic pump 16 is interposed in the middle of the first passage 19 via check valves 21 and 22, and similarly in the middle of the second passage 20 through the check valves 21 and 22. The second hydraulic pump 17 is interposed. The first passage 19 supplies the hydraulic oil in the first lifting adjustment mechanism 14 </ b> A to the second lifting adjustment mechanism 14 </ b> B by the operation of the first hydraulic pump 16, and the second passage 20 operates the second hydraulic pump 17. The hydraulic oil in the second lifting adjustment mechanism 14B is supplied to the first lifting adjustment mechanism 14A.

  The pump suction side of the first passage 19 (the suction port 16a side of the first hydraulic pump 16) and the pump discharge side of the second passage 20 (the discharge port 17b side of the second hydraulic pump 17) are the first flow. It is connected to the supply / discharge port 18A of the first lifting adjustment mechanism 14A via the path switching valve 23, and is connected to the pump discharge side (discharge port 16b side of the first hydraulic pump 16) and the second path 20 of the first passage 19. The pump suction side (the suction port 17a side of the second hydraulic pump 17) is connected to the supply / discharge port 18B of the second lift adjustment mechanism 14B via the second flow path switching valve 24. The first and second flow path switching valves 23 and 24 are constituted by electromagnetic three-port two-position switching valves, and supply / discharge of the first and second lifting / lowering adjustment mechanisms 14A and 14B by on / off control by a controller (not shown). The ports 18A and 18B can be selectively conducted to corresponding ports of the first passage 19 and the second passage 20. FIG. 1 shows a state where the energization of the first and second flow path switching valves 23 and 24 is off. In this state, the pump discharge sides of the second passage 20 and the first passage 19 are the first. , Are connected to the first and second elevation adjustment mechanisms 14A, 14B via the second flow path switching valves 23, 24.

  Further, branch passages 25 and 26 are provided on the pump suction sides of the first passage 19 and the second passage 20, respectively, and these branch passages 25 and 26 store hydraulic oil via a common opening / closing valve 27. Connected to the reservoir tank 28. The on-off valve 27 is constituted by an electromagnetic valve, and can open and close both branch passages 25 and 26 simultaneously by on / off control by a controller (not shown). The open / close valve 27 closes the branch passages 25 and 26 in the off state.

  This suspension device can be switched by a driver's switch operation between a normal mode in which active vehicle attitude control is not performed and an attitude control mode in which vehicle attitude is actively controlled in accordance with driving conditions. The vehicle height can be adjusted by operating another switch. Hereinafter, operations in the normal mode, the posture control mode, and the vehicle height adjustment will be sequentially described.

<Normal mode>
In the normal mode, as shown in FIG. 1, the first and second flow path switching valves 23 and 24 and the opening / closing valve 27 are turned off, and the motor 15 is also turned off. At this time, the first lift adjustment mechanism 14A is connected to the pump discharge side of the second passage 20 via the first flow path switching valve 23, and the second lift adjustment mechanism 14B is connected via the second flow path switching valve 24. Although connected to the pump discharge side of the first passage 19, the pump suction side of the first passage 19 and the second passage 20 is the first passage switching valve 23 and the second passage switching valve 24 on the main passage side. Since the branch passages 25 and 26 are closed by the opening / closing valve 27, the first and second lifting / lowering adjustment mechanisms 14A and 14B are blocked from flowing the hydraulic oil and locked. Therefore, in this state, the overall height of the left and right upper spring seats 5 with respect to the vehicle body is maintained constant.

<Attitude control mode>
In the posture control mode, for example, when posture control is performed to lower the left suspension unit 1A side in FIG. 2 and raise the right suspension unit 1B side, the second flow path switching valve 24 and the open / close valve are controlled by a controller (not shown). The first flow path switching valve 23 is switched to the on state while the motor 27 is in the off state, and the motor 15 is turned on in that state. As a result, the first and second hydraulic pumps 16 and 17 are driven by the motor 15, and the first lift adjustment mechanism 14 </ b> A and the second lift adjustment mechanism 14 </ b> B are connected by the first passage 19. Accordingly, at this time, the hydraulic oil in the first lifting adjustment mechanism 14A is sucked into the first hydraulic pump 16 as indicated by an arrow in FIG. Supplied to mechanism 14B. As a result, the attitude of the vehicle is controlled so that the left side is lowered and the right side is pushed up in FIG.
In addition, when posture control is performed in which the left suspension unit 1A side in FIG. 2 is raised and the right suspension unit 1B side is lowered, the second flow path switching valve 24 is turned on instead of the first flow path switching valve 23. On the contrary, the hydraulic oil in the second elevating mechanism 14B is supplied to the first elevating mechanism 14A by the operation of the second hydraulic pump 17.

  A recirculation passage that is opened and closed by a valve (not shown) is provided between the discharge ports 16b and 17b and the suction ports 16a and 17b of the first hydraulic pump 16 and the second hydraulic pump 17, respectively. When the hydraulic pump 16 (or 17) is performing the above-described pump operation for posture control, the return passage on the other hydraulic pump 17 (or 16) side is opened and the hydraulic pump 17 (or 16) is allowed to idle. It has come to be.

<Vehicle height adjustment-(1) Lift adjustment>
When the vehicle height is adjusted to increase, as shown in FIG. 3, all of the first and second flow path switching valves 23 and 24 and the opening / closing valve 27 are turned on, and the motor 15 is turned on in that state. As a result, the first and second hydraulic pumps 16 and 17 are driven by the motor 15, and the first lift adjustment mechanism 14 </ b> A and the second lift adjustment mechanism 14 </ b> B discharge the pumps in the second passage 20 and the first passage 19. It is connected to the reservoir tank 28 via the side and branch passages 26, 25. At this time, the hydraulic oil in the reservoir tank 28 is sucked in by the first and second hydraulic pumps 16 and 17, and the pump operation of both the hydraulic pumps 16 and 17 causes the second lifting adjustment mechanism 14B and the first lifting adjustment mechanism 14A to move. Supplied. As a result, the vehicle height is adjusted to rise.

<Vehicle height adjustment-(2) Descent adjustment>
When the vehicle height is adjusted downward, as shown in FIG. 4, the opening / closing valve 27 is turned on while the first and second flow path switching valves 23 and 24 and the motor 15 are turned off. As a result, the first elevating / lowering adjusting mechanism 14A and the second elevating / lowering adjusting mechanism 14B are connected to the reservoir tank 28 via the pump suction sides of the first passage 19 and the second passage 20 and the branch passages 25 and 26. At this time, the hydraulic oil in the first lifting adjustment mechanism 14A and the second lifting adjustment mechanism 14B is discharged to the reservoir tank 28, and as a result, the vehicle height is adjusted downward.

  As described above, this suspension apparatus supplies the hydraulic oil in one lifting adjustment mechanism 14A (or 14B) to the other lifting adjustment mechanism 14B (or 14A) by the action of the hydraulic pump 16 (or 17). Since the power of the hydraulic pump 16 (or 17) is added to the pressure of the hydraulic oil in one of the lift adjustment mechanisms 14A (or 14B), the other lift adjustment mechanism 14B (or 14A) is controlled. It is only necessary to supply hydraulic oil to the other, and it is possible to perform posture control with small pump power compared to the case where all the hydraulic oil pressure to be supplied to the other lift adjustment mechanism 14B (or 14A) is generated by only the hydraulic pump. . Therefore, the pump capacity required for operation can be reduced, the pump can be made compact, and the power consumption by the motor 15 can be greatly reduced.

  Further, in the case of this suspension device, the first flow path switching valve 23 and the second flow are kept while the first hydraulic pump 16 and the second hydraulic pump 17 are continuously operated by the common motor 15 during vehicle attitude control. Since the path switching valve 24 is switched and controlled by the controller, the supply and discharge of the hydraulic fluid of both the lifting adjustment mechanisms 14A and 14B is switched, so that the attitude control according to the change in the vehicle state during driving is performed with good responsiveness. Can do.

  In addition, the suspension device includes branch passages 25 and 26 connected to a reservoir tank 28 on the pump suction side of the first passage 19 and the second passage 20, and an open / close valve 27 that opens and closes the branch passages 25 and 26. While having a simple configuration, it is possible to realize a reliable vehicle height adjustment of the vehicle. Further, since a vehicle height adjusting function can be obtained only by adding a simple configuration to the hydraulic circuit 2 of the suspension device instead of providing a separate vehicle height adjusting device, the manufacturing cost is reduced by reducing the number of parts. The overall device can be made compact.

  In addition, this invention is not limited to the said embodiment, A various design change is possible in the range which does not deviate from the summary. For example, in the above embodiment, the first and second lifting / lowering adjusting mechanisms 14A and 14B by the base member 9 and the annular piston 11 are provided on the upper spring seat 5 side of the suspension unit, but the same lifting and lowering mechanism is provided on the lower spring seat 6 side. It is also possible to provide adjustment mechanisms 14A and 14B. It is also possible to apply the same configuration as described above to the suspension units at the front and rear of the vehicle body as a pair.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an embodiment of the present invention, and is a hydraulic circuit diagram of a vehicle suspension device in a normal mode. The hydraulic circuit diagram of the suspension apparatus for vehicles at the time of attitude control which shows the embodiment. The hydraulic circuit diagram of the suspension apparatus for vehicles at the time of raising the vehicle height, showing the embodiment. The hydraulic circuit diagram of the suspension apparatus for vehicles at the time of lowering the vehicle height, showing the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1A, 1B ... Suspension unit 2 ... Hydraulic circuit 3 ... Coil spring 5 ... Upper spring seat 6 ... Lower spring seat 14A ... 1st raising / lowering adjustment mechanism (elevation adjustment mechanism) 14B ... 2nd elevation adjustment mechanism (elevation adjustment mechanism) 15 ... Motor 16 ... first hydraulic pump 17 ... second hydraulic pump 19 ... first passage 20 ... second passage 23 ... first flow path switching valve (flow path switching valve) 24 ... second flow path switching valve ( 25, 26 ... Branch passage 27 ... Open / close valve 28 ... Reservoir tank

Claims (2)

The suspension unit that forms a pair of the left and right sides of the vehicle body or the front and rear is a coil spring that elastically connects the vehicle body and the wheel, an upper spring seat that supports the upper end of the coil spring on the vehicle body side, and a lower end of the coil spring. In a vehicle suspension device comprising a lower spring seat supported on a wheel side,
Each suspension unit is provided with a hydraulic lifting adjustment mechanism on at least one of the upper spring seat and the lower spring seat,
Connecting the lifting and lowering adjustment mechanism of the paired suspension unit to a hydraulic circuit including a first hydraulic pump and a second hydraulic pump driven by a common motor;
In this hydraulic circuit,
A first passage for supplying hydraulic oil in the lifting adjustment mechanism of one suspension unit to the lifting adjustment mechanism of the other suspension unit by the operation of the first hydraulic pump;
A second passage for supplying hydraulic oil in the lift adjustment mechanism of the other suspension unit to the lift adjustment mechanism of one suspension unit by the operation of the second hydraulic pump;
A flow path switching valve capable of switching connection between the first passage and the second passage with respect to both the lifting adjustment mechanisms,
A suspension apparatus for a vehicle, wherein the flow path switching valve is controlled in accordance with a running state of the vehicle. 2. The branch passage connected to a reservoir tank is provided on the pump suction side of the first passage and the second passage, and an opening / closing valve for opening and closing the branch passage is provided. Vehicle suspension device.

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