JP2005119563A - Vehicle suspension system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle suspension device capable of efficiently generating a damping force.
SOLUTION: In a vehicle 10, a left front wheel side electromagnetic suspension 24 and a left front wheel side hydraulic absorber 26 are provided between a vehicle body left front wheel side member 20 and a left front wheel side lower arm 22. A damping force is generated in the electromagnetic suspension 24. The ECU 100 controls the left front wheel side hydraulic pressure adjusting device 30 according to the damping force in the left front wheel side electromagnetic suspension 24 to generate a damping force by the left front wheel side hydraulic absorber 26. The right front wheel side electromagnetic suspension 44, the left rear wheel side electromagnetic suspension 64, and the right rear wheel side electromagnetic suspension 84 generate a damping force in the same manner as the left front wheel side electromagnetic suspension 24. The right front wheel side hydraulic absorber 46, the left rear wheel side hydraulic absorber 66, and the right rear wheel side hydraulic absorber 86 generate a damping force in the same manner as the left front wheel side hydraulic absorber 26.
[Selection] Figure 1

Description

  The present invention relates to a vehicle suspension device, and more particularly to a technique of a shock absorber provided in the vehicle suspension device.

2. Description of the Related Art Conventionally, there has been known a vehicle attitude control device that controls an attitude of a vehicle by operating an actuator disposed between an unsprung member and a sprung member of each wheel (see, for example, Patent Document 1). In this conventional attitude control device, the hydraulic pressure in the cylinder generates a damping force, and the attitude of the vehicle is controlled by generating an active damping force with a motor.
JP 2001-180244 A

  According to the above-described conventional technique, since the damping force due to the hydraulic pressure always acts, the damping force cannot be generated only by the motor, and a desired damping force may not be obtained. On the other hand, if all the loads are generated only by the motor without using any damping force due to the hydraulic pressure, the size of the motor is directly increased. Further, when the speed of the stroke, which is the vertical displacement of the vehicle body, reaches a high speed range, the output of the motor is lowered due to the influence of inductance, and a desired damping force may not be obtained. Further, as an unexpected situation when all loads are generated only by the motor, there is a possibility that a damping force cannot be obtained fundamentally if a malfunction occurs in the motor.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a vehicle suspension device that efficiently generates a damping force.

  In order to solve the above-described problem, a vehicle suspension apparatus according to an aspect of the present invention is a vehicle suspension apparatus that generates a damping force between an unsprung member and an unsprung member by a motor and hydraulic pressure, and is adapted to the damping force by the motor. And a hydraulic damping force adjusting means for changing the damping force by the hydraulic pressure. The hydraulic damping force adjusting means includes, for example, a hydraulic shock absorber, a variable orifice provided therein, a step motor for adjusting the opening of the variable orifice, a hydraulic adjustment device for driving the step motor, and the number of drive steps of the step motor. You may implement | achieve with the structure of the electronic controller etc. which determine. The vehicle suspension device may further include a motor damping force adjusting unit that actively changes the damping force of the motor. The motor damping force adjusting means may be realized by a configuration of an electromagnetic shock absorber, an electromagnetic motor constituting a part thereof, an electronic control device for controlling the electromagnetic motor, or the like.

  According to the vehicle suspension device of this aspect, the magnitude of the damping force by the motor and the magnitude of the damping force by the hydraulic pressure are related, and either or both of the damping force by the motor and the damping force by the hydraulic pressure are adjusted. The generation of damping force for the required load is shared by the motor and hydraulic pressure. Therefore, the optimum damping force according to the situation can be obtained more efficiently, and the motor can be reduced in size as compared with the configuration in which the damping force is generated only by the motor. The vehicle suspension apparatus may actively change the damping force by the motor in accordance with the damping force by the hydraulic pressure in order to maintain the relationship between the damping force by the motor and the damping force by the hydraulic pressure.

  In the vehicle suspension system according to this aspect, the hydraulic damping force adjusting means may increase the damping force due to the hydraulic pressure when the damping force due to the motor increases. In this vehicle suspension system, when the required load is large, the damping force by the motor is assisted by the damping force by the hydraulic pressure. Therefore, it is possible to reduce the size of the motor by distributing the load on the motor with respect to the required load to the hydraulic pressure. Further, it is possible to generate a larger damping force by using both the motor and the hydraulic pressure.

  In the vehicle suspension device according to this aspect, the hydraulic damping force adjusting means may reduce the damping force due to the hydraulic pressure when the damping force due to the motor is reduced. This vehicle suspension system reduces the damping force due to the hydraulic pressure when the required load is small, so that the optimum damping force for the required load can be efficiently generated as a whole without actively operating the motor. Power consumption for actively operating the motor can also be reduced.

  In the vehicle suspension device according to this aspect, the hydraulic damping force adjusting means may increase the damping force due to the hydraulic pressure when the damping force due to the motor is reduced. In the vehicle suspension system according to this aspect, the motor damping force adjusting unit may reduce the damping force by the motor when the hydraulic damping force adjusting unit increases the damping force by the hydraulic pressure. This vehicle suspension system can reduce the size of the motor by distributing the load on the motor with respect to the required load to the hydraulic pressure, and can efficiently generate the optimum damping force with respect to the required load. Further, power consumption for actively operating the motor can be reduced.

  In the vehicle suspension apparatus according to this aspect, the hydraulic damping force adjusting means may reduce the damping force due to the hydraulic pressure when the thrust by the motor increases. This vehicle suspension device can be controlled so that the thrust generated by the motor is not lost by the damping force due to the hydraulic pressure.

  ADVANTAGE OF THE INVENTION According to this invention, the vehicle suspension apparatus which generates a damping force efficiently can be provided.

(First embodiment)
The vehicle suspension apparatus according to the present embodiment includes an electromagnetic suspension that generates a damping force by a motor and a hydraulic absorber that generates a damping force by hydraulic pressure, corresponding to each wheel of the vehicle. The damping force generated by the hydraulic absorber is variable, and the damping force by the hydraulic absorber is adjusted according to the magnitude of the damping force generated by the electromagnetic suspension. The vehicle suspension apparatus in the present embodiment can efficiently generate an appropriate damping force for a required load by providing a relationship between the damping force by the motor and the damping force by the hydraulic pressure.

  FIG. 1 shows a configuration of a vehicle suspension apparatus according to a first embodiment of the present invention. The vehicle 10 includes a first vehicle suspension device 12, a second vehicle suspension device 14, a third vehicle suspension device 16, and a fourth vehicle suspension device 18 that are respectively a left front wheel 110, a right front wheel 112, a left rear wheel 114, and a right rear wheel. 116 in preparation for correspondence. The first vehicle suspension device 12, the second vehicle suspension device 14, the third vehicle suspension device 16, and the fourth vehicle suspension device 18 generate a damping force between the sprung member and the unsprung member of the vehicle 10, respectively. A member on the vehicle body supported by a coil spring (not shown) is referred to as a “sprung” or “sprung member”, and a member on the wheel that is not supported by the coil spring is referred to as “unsprung” or “sprung member”. Call.

  The first vehicle suspension device 12 includes a left front wheel side electromagnetic suspension 24 and a left front wheel side hydraulic absorber 26. The left front wheel side electromagnetic suspension 24 and the left front wheel side hydraulic absorber 26 are attached between the left front wheel side member 20 of the vehicle body that is a sprung member and the left front wheel side lower arm 22 that is an unsprung member. The second vehicle suspension device 14 includes a right front wheel side electromagnetic suspension 44 and a right front wheel side hydraulic absorber 46. The right front wheel side electromagnetic suspension 44 and the right front wheel side hydraulic absorber 46 are attached between a vehicle body right front wheel side member 40 that is a sprung member and a right front wheel side lower arm 42 that is an unsprung member. The third vehicle suspension device 16 includes a left rear wheel side electromagnetic suspension 64 and a left rear wheel side hydraulic absorber 66. The left rear wheel side electromagnetic suspension 64 and the left rear wheel side hydraulic absorber 66 are attached between the left rear wheel side member 60 of the vehicle body that is a sprung member and the left rear wheel side lower arm 62 that is an unsprung member. The fourth vehicle suspension device 18 includes a right rear wheel side electromagnetic suspension 84 and a right rear wheel side hydraulic absorber 86. The right rear wheel side electromagnetic suspension 84 and the right rear wheel side hydraulic absorber 86 are attached between the vehicle body right rear wheel side member 80 that is a sprung member and the right rear wheel side lower arm 82 that is an unsprung member.

  The first vehicle suspension device 12, the second vehicle suspension device 14, the third vehicle suspension device 16, and the fourth vehicle suspension device 18 operate in the same manner with the same configuration. Hereinafter, the configuration and operation of the vehicle suspension apparatus will be described using the first vehicle suspension apparatus 12 as an example.

  The left front wheel side electromagnetic suspension 24 of the first vehicle suspension device 12 includes a coil spring and an electromagnetic shock absorber. The coil spring is contracted between the left front wheel side member 20 of the vehicle body, which is a sprung member, and the left front wheel side electromagnetic suspension 24 to support the weight on the spring, and vibrations and impacts from the road surface are passed through the left front wheel 110 through the left front wheel 110. Suppresses being transmitted to. The electromagnetic shock absorber attenuates the vertical vibration of the vehicle body caused by the coil spring. This electromagnetic shock absorber can actively generate a damping force or a thrust between the sprung and unsprung portions of the vehicle using a motor, and has excellent control response.

  The electromagnetic shock absorber has members such as a left front wheel motor 28, a ball screw, and a rod as a configuration on the upper side of the spring, and members such as a ball screw nut and an outer shell as a configuration on the lower side of the spring. The left front wheel side motor 28 supports one end of the ball screw by serration so as to be rotatable. The ball screw is in a state of being engaged with the ball screw nut, and when the ball screw rotates relative to the ball screw nut, the rod slides in the vertical direction within the outer shell. When the ball screw rotates relative to the ball screw nut, the left front wheel side motor 28 rotates and acts as a generator, and a damping force is generated by the resistance force of the left front wheel side motor 28 generated at this time. Further, when a drive current is applied to the left front wheel side motor 28, the left front wheel side motor 28 is actively operated to generate a damping force or a thrust. Whether the load generated in the left front wheel side motor 28 acts as a damping force or a thrust depends on the direction of the drive current, the direction of expansion / contraction of the required load, and its magnitude.

  The left front wheel side hydraulic absorber 26 of the first vehicle suspension device 12 is a hydraulic shock absorber that generates a damping force by hydraulic pressure, and attenuates the vertical vibration of the vehicle body by the coil spring of the left front wheel side electromagnetic suspension 24. The left front wheel side hydraulic absorber 26 has a member such as a piston as an upper spring configuration, and a member such as a cylinder as an unspring configuration. The cylinder is filled with hydraulic oil. When the piston slides in the vertical direction in the cylinder, the hydraulic oil moves through the variable orifice. The variable orifice is provided in the piston or cylinder. The opening of the variable orifice is variable, and a flow path resistance corresponding to the opening is generated. Accordingly, the flow path resistance of the variable orifice generated when the piston moves up and down in the cylinder becomes the damping force against the coil spring of the left front wheel side electromagnetic suspension 24.

  The left front wheel side hydraulic pressure adjusting device 30 increases or decreases the magnitude of the damping force due to the hydraulic pressure by changing the opening of the variable orifice. The left front wheel side hydraulic pressure adjusting device 30 includes a step motor for adjusting the opening of the variable orifice.

  In the second vehicle suspension device 14, the third vehicle suspension device 16, and the fourth vehicle suspension device 18, the right front wheel side electromagnetic suspension 44, the left rear wheel side electromagnetic suspension 64, and the right rear wheel side electromagnetic suspension 84 are the first The operation is the same as that of the left front wheel side electromagnetic suspension 24 of the vehicle suspension device 12. The right front wheel side hydraulic absorber 46, the left rear wheel side hydraulic absorber 66 and the right rear wheel side hydraulic absorber 86 operate in the same manner as the left front wheel side hydraulic absorber 26 of the first vehicle suspension device 12. The right front wheel side motor 48 of the right front wheel side electromagnetic suspension 44, the left rear wheel side motor 68 of the left rear wheel side electromagnetic suspension 64, and the right rear wheel side motor 88 of the right rear wheel side electromagnetic suspension 84 are the left front wheel side electromagnetic suspension 24. The same operation as that of the left front wheel side motor 28 is performed. The right front wheel side hydraulic pressure adjusting device 50, the left rear wheel side hydraulic pressure adjusting device 70, and the right rear wheel side hydraulic pressure adjusting device 90 operate in the same manner as the left front wheel side hydraulic pressure adjusting device 30, respectively.

  The vehicle 10 further includes an electronic control device (hereinafter referred to as “ECU”) 100, a stroke sensor 102, an acceleration sensor 104, a rudder angle sensor 106, and a vehicle speed sensor 108. The ECU 100 includes a CPU, a RAM, and a ROM. The stroke sensor 102 calculates a stroke speed that is a relative vertical displacement speed of the sprung member and the unsprung member based on the rotation angle detected by the rotation angle sensor provided in the vicinity of the rotation axis of each wheel. As another configuration, the stroke sensor 102 may obtain the stroke speed from the rotation angle of each motor such as the left front wheel side motor 28.

  The acceleration sensor 104 detects acceleration such as vertical acceleration, longitudinal acceleration, and lateral acceleration of the vehicle body for each wheel. The steering angle sensor 106 detects the steering angle of each wheel. The vehicle speed sensor 108 detects the vehicle speed of the vehicle 10. The ECU 100 determines the state of the vehicle 10 based on at least one of detection results such as stroke speed, acceleration, steering angle, and vehicle speed received from the stroke sensor 102, acceleration sensor 104, steering angle sensor 106, and vehicle speed sensor 108. To do. The ECU 100 controls the first vehicle suspension device 12, the second vehicle suspension device 14, the third vehicle suspension device 16, and the fourth vehicle suspension device 18 according to the determined state of the vehicle 10.

  Next, control of each vehicle suspension device by the ECU 100 will be described by taking the first vehicle suspension device 12 as an example. When the vehicle 10 is traveling on a good road, the ECU 100 sets the value of the drive current applied to the left front wheel side motor 28 of the left front wheel side electromagnetic suspension 24 to, for example, a reference current value of 0A. For example, when the road surface is uneven, the ECU 100 sets the value of the drive current applied to the left front wheel side motor 28 according to the vertical stroke speed of the vehicle body, and adjusts the damping force of the left front wheel side electromagnetic suspension 24 by the electromagnetic absorber. . The ECU 100 generates an active damping force or thrust force by giving the left front wheel side motor 28 a drive current in the same direction or in the opposite direction to the current generated by electromagnetic induction as well as the generation of the damping force inside the left front wheel side motor 28. You may let them. The ECU 100 may determine the value of the drive current applied to the left front wheel side motor 28 in order to control the posture of the vehicle body in accordance with detection results such as acceleration, steering angle, and vehicle speed.

  The ECU 100 adjusts the damping force by the left front wheel side hydraulic absorber 26 according to the damping force by the left front wheel side electromagnetic suspension 24. The ECU 100 calculates the number of driving steps of the step motor that changes the opening of the variable orifice of the left front wheel side hydraulic absorber 26 in order to adjust the damping force by the left front wheel side hydraulic absorber 26, and the number of driving steps is calculated on the left front wheel side. It transmits to the hydraulic pressure adjusting device 30. The left front wheel side hydraulic pressure adjustment device 30 drives the step motor based on the number of drive steps received from the ECU 100.

  FIG. 2 schematically shows the relationship between the sprung member, the unsprung member, the coil spring, the electromagnetic absorber, and the hydraulic absorber. The unsprung member 120 includes a left front wheel 110, a right front wheel 112, a left rear wheel 114, a right rear wheel 116, a left front wheel side lower arm 22, a right front wheel side lower arm 42, a left rear wheel side lower arm 62, a right rear wheel side lower arm 82, and the like. The wheel side member. The sprung member 122 is a member on the vehicle body side such as the vehicle body left front wheel side member 20, the vehicle body right front wheel side member 40, the vehicle body left rear wheel side member 60, the vehicle body right rear wheel side member 80, and the like. Between the unsprung member 120 and the sprung member 122, an electromagnetic absorber 124 and a hydraulic absorber 126 are provided in parallel, and the electromagnetic absorber 124, the hydraulic absorber 126, and a coil spring 128 are provided in parallel. The electromagnetic absorber 124 and the coil spring 128 constitute the left front wheel side electromagnetic suspension 24, the right front wheel side electromagnetic suspension 44, the left rear wheel side electromagnetic suspension 64, and the right rear wheel side electromagnetic suspension 84, respectively. The hydraulic absorber 126 corresponds to the left front wheel side hydraulic absorber 26, the right front wheel side hydraulic absorber 46, the left rear wheel side hydraulic absorber 66, and the right rear wheel side hydraulic absorber 86. The electromagnetic absorber 124, the hydraulic absorber 126, and the coil spring 128 constitute the first vehicle suspension device 12, the second vehicle suspension device 14, the third vehicle suspension device 16, and the fourth vehicle suspension device 18, respectively.

  Either or either of the electromagnetic absorber 124 and the hydraulic absorber 126 generates a damping force for damping the vertical vibration of the coil spring 128. The hydraulic absorber 126 generates a hydraulic damping force in accordance with the damping force generated by the motor in the electromagnetic absorber 124. As schematically shown in FIG. 2, the electromagnetic absorber 124 and the hydraulic absorber 126 are in a mutually supporting relationship, and a load related to generation of a damping force with respect to the required load is distributed to the electromagnetic absorber 124 and the hydraulic absorber 126. Thereby, this vehicle suspension apparatus can generate | occur | produce optimal damping force efficiently.

  FIG. 3 is a graph showing the relationship between the stroke speed in the vertical movement of the vehicle body and the load generated in the electromagnetic absorber 124. The stroke and the generated load act in one of the extending direction and the contracting direction of the electromagnetic absorber 124, respectively. On the horizontal axis, the positive direction indicates the stroke speed in the extension direction, and the negative direction indicates the stroke speed in the contraction direction. On the vertical axis, the positive direction indicates the generated load in the expansion direction, and the negative direction indicates the generated load in the contraction direction. A first curve 130 indicated by a solid line indicates a load generated in the motor in a state where no drive current is applied to the motor of the electromagnetic absorber 124. As the stroke speed increases in the extension direction, a load is generated on the motor as a damping force in the extension direction, and as the stroke speed increases in the contraction direction, a load is generated on the motor as a damping force in the contraction direction.

  A second curve 132 indicated by a broken line indicates a load generated in the motor in a state where a driving current is applied to increase the load generated in the motor of the electromagnetic absorber 124 in the extension direction. If a stroke in the extension direction occurs with a driving current applied to increase the load generated in the motor in the extension direction, the load generated in the motor appears in the first quadrant of the graph, and the load in the extension direction generated in the motor is Greater than no drive current applied. On the other hand, if a stroke in the contraction direction occurs with a drive current that increases the load generated in the motor in the extension direction, the stroke in the contraction direction is small and the load generated in the motor appears in the second quadrant of the graph. A load is generated on the motor as an active thrust in the extension direction against the stroke in the contraction direction. In addition, when the stroke generated in the contraction direction is large with the drive current increasing the load generated in the motor in the extension direction and the load generated in the motor appears in the third quadrant of the graph, the contraction direction generated in the motor The load is smaller than the state where no drive current is applied.

  A third curve 134 indicated by a broken line indicates a load generated in the motor in a state where a driving current is applied to increase the load generated in the motor of the electromagnetic absorber 124 in the contracting direction. When the stroke in the extension direction is large with the drive current applied to increase the load generated in the motor in the shrinking direction and the load generated in the motor appears in the first quadrant of the graph, the load in the extension direction generated in the motor is driven. It is smaller than the state where no current is applied. On the other hand, if the stroke in the extension direction is small with the driving current applied to increase the load generated in the motor in the contraction direction and the load generated in the motor appears in the fourth quadrant of the graph, the contraction is opposite to the stroke in the extension direction. A load is generated on the motor as an active thrust in the direction. Also, when a stroke in the contraction direction occurs with a drive current that increases the load generated in the motor in the contraction direction, the load generated in the motor appears in the third quadrant of the graph and the contraction direction generated in the motor The load is larger than the state in which no drive current is applied.

  FIG. 4 is a graph showing the relationship between the stroke speed in the vertical movement of the vehicle body and the load generated in the hydraulic absorber 126. The stroke and the generated load act in either direction of expansion or contraction of the hydraulic absorber 126, respectively. On the horizontal axis, the positive direction indicates the stroke speed in the extension direction, and the negative direction indicates the stroke speed in the contraction direction. On the vertical axis, the positive direction indicates the generated load in the expansion direction, and the negative direction indicates the generated load in the contraction direction. A fourth curve 136 and a fifth curve 138 indicate loads generated in the hydraulic absorber 126. However, the fourth curve 136 shows a state where the opening of the variable orifice of the hydraulic absorber 126 is reduced, while the fifth curve 138 shows a state where the opening of the variable orifice of the hydraulic absorber 126 is increased.

  As the stroke speed increases in the extension direction, a load of the hydraulic absorber 126 is generated as a damping force in the extension direction, and the load appears in the first quadrant of the graph. As the stroke speed increases in the contraction direction, a load on the hydraulic absorber 126 is generated as a damping force in the contraction direction, and the load appears in the third quadrant of the graph. In the state indicated by the fourth curve 136 in which the opening degree of the variable orifice of the hydraulic absorber 126 is reduced, the expansion direction or the contraction direction in the state indicated by the fifth curve 138 in which the opening degree of the variable orifice of the hydraulic absorber 126 is increased. The generated load as a damping force is large.

  Here, the control of the damping force by the ECU 100 based on the characteristics of the electromagnetic absorber 124 and the hydraulic absorber 126 shown in FIGS. 3 and 4 will be described. The ECU 100 determines the opening degree of the variable orifice of the hydraulic absorber 126 according to the magnitude of the damping force by the motor of the electromagnetic absorber 124. For example, when the required load is large and the damping force by the electromagnetic absorber 124 should be increased, the ECU 100 decreases the opening of the variable orifice of the hydraulic absorber 126 to increase the hydraulic damping force, and the hydraulic absorber against the required load. When the damping force by 126 is insufficient, the shortage may be supplemented by the damping force by the electromagnetic absorber 124. For example, regardless of the magnitude of the required load, the damping force by the electromagnetic absorber 124 may be reduced by the amount by which the damping force by the hydraulic absorber 126 is increased, or both the damping force by the hydraulic absorber 126 and the damping force by the electromagnetic absorber 124 may be reduced. It may be increased. For example, when the required load is small and the damping force by the electromagnetic absorber 124 is also small, the ECU 100 may obtain an optimum damping force by increasing the opening of the variable orifice of the hydraulic absorber 126 to reduce the hydraulic damping force. .

  In this way, by compensating each other with the damping force by the electromagnetic absorber 124 and the damping force by the hydraulic absorber 126, an optimum load can be efficiently generated as the damping force for the required load. The motor can be reduced in size as compared with the configuration in which the damping force with respect to the required load is generated only by the electromagnetic absorber 124, and the necessary load can be covered with the damping force by the hydraulic absorber 126 even if a malfunction occurs in the motor as an unexpected situation. it can. Even when the stroke speed in the vertical movement of the vehicle body reaches a high speed range, the damping force by the electromagnetic absorber 124 can be supplemented by the damping force by the hydraulic absorber 126, so that the required load can be efficiently satisfied. Since the damping force by the hydraulic absorber 126 is optimized, the necessity of actively generating the damping force and thrust by the electromagnetic absorber 124 is reduced, so that there is also an effect of power saving.

  The ECU 100 reduces the damping force by the hydraulic absorber 126 so as not to lose the thrust when the electromagnetic absorber 124 generates an active thrust in the extending direction or the contracting direction. As a result, the thrust generated by the electromagnetic absorber 124 works sufficiently, and the operation efficiency of the electromagnetic absorber 124 can be improved.

FIG. 5 is a flowchart illustrating the control process of the electromagnetic absorber 124 and the hydraulic absorber 126 by the ECU 100. Each sensor such as the stroke sensor 102 and the acceleration sensor 104 detects a vehicle state such as a stroke speed and vertical acceleration (S10). The ECU 100 calculates a required load on each wheel such as the left front wheel 110 (S12), and determines in which region the calculated required load is located on the graphs shown in FIGS. As a result of determination in S14, when the required load belongs to the first quadrant or the third quadrant on the graphs of FIGS. 3 and 4, that is, when the required load × stroke speed is greater than zero (S16Y), the ECU 100 If it is determined whether or not the required load can be satisfied with the damping force of the hydraulic absorber 126 (S18N), control is performed to compensate for the shortage with the damping force of the electromagnetic absorber 124. (S20). When it is determined that the required load can be satisfied with the damping force by the hydraulic absorber 126 (S18Y), the ECU 100 adjusts the damping force with the hydraulic pressure (S24). In S16, when the required load belongs to the second quadrant or the fourth quadrant on the graphs of FIGS. 3 and 4, that is, when the required load × stroke speed is smaller than zero (S16N), the ECU 100 reduces the damping force by the hydraulic absorber 126. To improve the operational efficiency of the electromagnetic absorber 124 (S22).
(Second Embodiment)
The present embodiment is different from the first embodiment in that a linear motor is used as a mechanism for generating a damping force by the motor. Hereinafter, the difference from the first embodiment will be mainly described.

  FIG. 6 shows a vehicle suspension apparatus according to the second embodiment. This vehicle suspension mainly includes a linear motor absorber 140 and a hydraulic absorber 142. The linear motor absorber 140 includes a fixed cylinder provided with an electromagnetic coil 148 as a configuration on the upper side of the spring and a hydraulic absorber 142 capable of sliding in the vertical direction within the fixed cylinder as a configuration on the lower side of the spring. A plurality of permanent magnets 150 are provided on the outer peripheral surface of the hydraulic absorber 142 so that N poles and S poles are alternately arranged. The permanent magnets 150 react to magnetic flux generated by the electromagnetic coil 148, and the hydraulic absorber 142 is guided in the vertical direction and slides in the fixed cylinder. In such a linear motor structure, the magnetic force between the electromagnetic coil 148 and the permanent magnet 150 acts as a damping force. When ECU 100 changes the direction and magnitude of the current flowing to electromagnetic coil 148, the direction and magnitude of the damping force or thrust generated in linear motor absorber 140 changes.

  The hydraulic absorber 142 includes a shaft 152 and a step motor 144 as a configuration on the upper side of the spring, and includes a cylinder attached to the lower arm via a lower arm side mounting portion 146 as a configuration on the lower side of the spring. The hydraulic absorber 142 has the same configuration as the hydraulic absorber 126 in the first embodiment and operates in the same manner. The step motor 144 changes the opening of the variable orifice of the hydraulic absorber 142. Step motor 144 is driven based on the number of drive steps calculated by ECU 100.

  In the vehicle suspension apparatus shown in FIG. 6 as well, the linear motor absorber 140 and the hydraulic absorber 142 functioning as an electromagnetic absorber are theoretically provided in parallel as in the first embodiment. Since the ECU 100 changes the damping force in the hydraulic absorber 142 according to the damping force generated in the linear motor absorber 140, the same effect as in the first embodiment can be obtained.

  The present invention has been described above based on the embodiment. The present invention is not limited to this embodiment, and various modifications thereof are also effective as aspects of the present invention. For example, in each embodiment, the mechanism for adjusting the opening of the variable orifice of the hydraulic absorber with a step motor has been described. However, in a modified example, the opening of the variable orifice of the hydraulic absorber is adjusted using an actuator such as an electromagnetic solenoid. You may employ | adopt the mechanism to adjust.

It is a figure which shows the structure of the vehicle suspension apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows typically the relationship between a sprung member, an unsprung member, a coil spring, an electromagnetic absorber, and a hydraulic absorber. It is a figure which shows the relationship between the stroke speed between an unsprung and unsprung and the load which generate | occur | produces in an electromagnetic absorber. It is a figure which shows the relationship between the stroke speed between a sprung and unsprung and the load which generate | occur | produces in a hydraulic absorber. It is a flowchart which shows the control process of the electromagnetic absorber and hydraulic absorber by ECU. It is a figure which shows the structure of the vehicle suspension apparatus which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Vehicle, 12 1st vehicle suspension apparatus, 14 2nd vehicle suspension apparatus, 16 3rd vehicle suspension apparatus, 18 4th vehicle suspension apparatus, 100 ECU, 102 Stroke sensor, 104 Acceleration sensor, 120 Unsprung member, 122 On spring Members, 124 electromagnetic absorbers, 126 hydraulic absorbers, 128 coil springs, 140 linear motor absorbers, 142 hydraulic absorbers.

Claims (5)

In a vehicle suspension device that generates a damping force between an unsprung member and an unsprung member by a motor and hydraulic pressure,
A vehicle suspension device comprising: a hydraulic damping force adjusting means for changing a damping force by the hydraulic pressure in accordance with a damping force by the motor.   The vehicle suspension apparatus according to claim 1, wherein the hydraulic damping force adjusting means increases the damping force due to the hydraulic pressure when the damping force due to the motor increases.   2. The vehicle suspension apparatus according to claim 1, wherein the hydraulic damping force adjusting means reduces the damping force due to the hydraulic pressure when the damping force due to the motor is reduced.   2. The vehicle suspension apparatus according to claim 1, wherein the hydraulic damping force adjusting means increases the damping force due to the hydraulic pressure when the damping force due to the motor is reduced.   The vehicle suspension apparatus according to claim 1, wherein the hydraulic damping force adjusting means reduces the damping force due to the hydraulic pressure when thrust generated by the motor is generated.

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