JP2008114745A - Vehicular suspension system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the practicality of a suspension system with a solenoid absorber for generating resistance force with respect to relative action of the upper part of a spring and the lower part of the spring. <P>SOLUTION: The electromagnetic absorber with two electromagnetic motors is adopted and a plurality of current-carrying terminals of a second electromagnetic motor are mutually electrically connected. In that state the resistance force which the absorber generates is controlled by connecting a first electromagnetic motor with a power source and adjusting electric current flowing the electromagnetic motor. When stroke speed is high, the second electromagnetic motor generates force in dependent on electromotive force, so that the reduction of force which the first electromagnetic motor generates is compensated, and accordingly the shortage of damping force when the stroke speed is high is suppressed. Namely, the suspension system has an advantage of suppressing the degradation of the ride comfort or the like of a vehicle, so that a suspension system has high practicality. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a suspension system for a vehicle that includes an electromagnetic absorber that generates a resistance force against relative movement between an upper portion and an unspring portion.

In recent years, as a vehicle suspension system, instead of a conventional suspension system provided with a hydraulic absorber, for example, an electromagnetic motor for relative movement between an upper part and an unsprung part as described in the following patent document. A suspension system including an electromagnetic absorber that generates a resistance force that depends on the force of the so-called electromagnetic suspension system has been studied. Such a suspension system is capable of appropriately controlling the magnitude of the resistance force by controlling the force of the electromagnetic motor, and has a high performance because it can easily realize suspension characteristics based on the so-called skyhook theory. Expected to be a suspension system.
JP 2005-256888 A

  The electromagnetic suspension system currently under study is referred to as “stroke operation” because it can be considered as relative movement between the sprung part and the unsprung part (it can be considered as a stroke action with respect to one of the sprung part and the unsprung part). However, there is a problem that the resistance force (damping force) is insufficient when a high-speed stroke operation is forced due to road surface unevenness or the like. Such a lack of damping force contributes to a deterioration in the ride comfort of the vehicle and the maneuverability / stability of the vehicle. Since the electromagnetic suspension system is still under development, it has various problems including the problem of insufficient damping force, leaving much room for improvement for improving practicality. The present invention has been made in view of such circumstances, and an object thereof is to provide a highly practical suspension system.

  In order to solve the above-described problems, the vehicle suspension system of the present invention employs an electromagnetic absorber having two electromagnetic motors, and electrically connects a plurality of energizing terminals of one of the electromagnetic motors. In this state, the other electromagnetic motor is connected to the power source and the current flowing through the electromagnetic motor is adjusted to control the resistance force generated by the absorber.

  According to the suspension system of the present invention, when the stroke speed is high, the one electromagnetic motor generates a force depending on the electromotive force, so that a decrease in the force generated by the other electromagnetic motor can be compensated. It is possible to suppress a dampening force shortage when the stroke speed is high. In other words, the present suspension system has the advantage that deterioration of the riding comfort of the vehicle can be suppressed, so that the suspension system of the present invention becomes a highly practical system.

Aspects of the Invention

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

  In each of the following items, the item (1) corresponds to the item (1), and the item (2) and the item (3), which are limited by the technical features of the item (1), are claimed in the item (2). Claim 1 or Claim 2 with limitations due to the technical features of (5) is added to Claim 3, and any one of Claims 1 to 3 is provided with the technical features of (7) to (9). What is limited by the feature is claimed in claim 4, and what is limited by the technical feature of (10) in claim 4 is claimed in claim 5, and in claim 5 according to the technical feature of (11). The limitation is added to claim 6, the claim 6 is limited by the technical feature of (12), the claim is limited to claim 7, and the limitation of the technical feature of (13) is added to claim 6. The additions correspond to claim 8 respectively.

(1) A first electromagnetic motor and a second electromagnetic motor, which are disposed between a spring top and a spring bottom, and operate in accordance with the relative movement between the spring top and the spring bottom, respectively. An electromagnetic absorber that generates a resistance force against the relative motion of the sprung portion and the unsprung portion depending on the force generated by
A control device for controlling the absorber, wherein the plurality of energization terminals of the second electromagnetic motor are electrically connected to each other, and in this state, the first electromagnetic motor and a power source are connected and the first electromagnetic A vehicle suspension system comprising: a control device capable of executing a specific resistance force control for controlling the resistance force generated by the absorber by adjusting a current flowing through the motor.

  In general, an electromagnetic motor has a limited range of motor operating speed that can generate a large force (in the case of a rotating motor, a range of rotating speed that can generate a large rotating torque). ing. For this reason, in the absorber provided in the electromagnetic suspension system currently being studied, for example, in a range where the operating speed is low due to the importance of damping effect of relatively low-frequency vibration such as sprung resonance frequency range. An electromagnetic motor that can reliably generate a large force is employed. In such an electromagnetic motor, generally, the force that can be generated decreases as the operation speed increases due to the influence of a time constant or the like, and the damping force becomes insufficient when the operation speed is high.

  The aspect of this section has been made in view of the above circumstances, and the aspect described in this section employs an electromagnetic absorber having two electromagnetic motors, and conducts electricity between the energization terminals of one of the electromagnetic motors. In this state, the resistance force generated by the absorber is controlled by controlling the other electromagnetic motor. According to the aspect of this section, when the relative motion speed (stroke speed) between the sprung portion and the unsprung portion is high, the force depending on the electromotive force generated by the second electromagnetic motor, which is the one electromagnetic motor, It is possible to compensate for a decrease in force generated by the first electromagnetic motor, which is the other electromagnetic motor. Accordingly, deficiency of damping force when the stroke speed is high is suppressed or prevented, and deterioration of the riding comfort of the vehicle can be effectively suppressed or prevented.

  The two “electromagnetic motors” in the aspect of this section are not particularly limited in type, and various types of motors such as a brushless DC motor can be adopted, and in terms of operation, they are rotary motors. Alternatively, a linear motor may be used. Furthermore, the “absorber” is not limited to one that can only generate a resistance force. For example, as will be described later, a propulsive force that actively moves the upper and lower portions of the spring and input from the outside. However, it may be possible to generate a force that prevents relative movement between the sprung portion and the unsprung portion, specifically, a vehicle body posture control force for suppressing the roll and pitch of the vehicle body.

  Of the two electromagnetic motors described above, the “first electromagnetic motor (hereinafter sometimes simply referred to as“ first motor ”)” is generated when an energization current that is a current flowing through itself is controlled by the control device. The force is to be controlled. The first motor may generate power by being supplied with electric power from a power source, or may generate a force that functions as a generator and depends on the electromotive force. That is, the control device is configured to be able to control the energization current regardless of whether it is a supply current from the power source to the first motor or a generation current of the first motor when the first motor functions as a generator. It is desirable that That is, in the suspension system according to the aspect of this section, it is desirable that the control device includes a “drive circuit” for driving the first motor, more specifically, for controlling the energization current. In consideration of power saving of the system, it is desirable that the drive circuit, the power source, and the like have a structure that can regenerate the current generated by the first motor.

  Further, the “second electromagnetic motor (hereinafter sometimes simply referred to as“ second motor ”)” does not receive power supply because the plurality of current-carrying terminals are electrically connected to each other in the specific resistance control. This generates power that depends on the electromotive force. The “conduction between current-carrying terminals” may be a state where some resistance exists between the current-carrying terminals, or may be a state where the current-carrying terminals are short-circuited. By the way, when a short circuit is made, it is possible to generate a larger force than when a resistor is present. In addition, the second motor connected to the power source and configured to conduct between the energization terminals by the control of the drive circuit or the like is not excluded, but for example, simplification of the system is considered. In this case, it is desirable to be configured not to be connected to the power source. Incidentally, the control device can open the plurality of energization terminals of the second motor, and controls the resistance force generated in the absorber by controlling the energization current of the first motor in that state. Resistance control may be performed.

  In addition, since the second motor compensates for a decrease in force generated by the first motor when the stroke speed is high, the mode of this section is applied between the energization terminals in the first motor when the stroke speed is low. When the force generated when short-circuiting is greater than the force generated when short-circuiting between the current-carrying terminals in the second motor, and when the stroke speed is high, when the current-carrying terminals in the second motor are short-circuited It is desirable that the force generated in the above is greater than the force generated when the energization terminals in the first motor are short-circuited. To put it plainly, the aspect is that the first motor is a low-speed motor (a low-rotation motor in the case of a rotary motor) that is a motor that can obtain a large output in a relatively low-speed operation, and the second motor is relatively In this mode, the motor is a high-speed motor (a high-speed motor in the case of a rotary motor) that is a motor that can obtain a large output in a high-speed operation.

(2) The absorber can also generate a propulsive force for relative movement between the spring top and the spring bottom.
The control device can execute a propulsive force control for controlling the propulsive force generated by the absorber by adjusting a current flowing through the first electromagnetic motor while supplying a current from a power source to the first electromagnetic motor. The vehicle suspension system according to item (1).

  In the embodiment described in this section, the sprung vibration damping control (skyhook) that generates a damping force against the sprung vibration based on the sprung absolute speed, and the damping force against the unsprung vibration generated based on the unsprung absolute speed. This is a mode in which unsprung vibration damping control (ground hook), combined vibration damping control, and the like can be executed. In the aspect of this section, vehicle height change control that generates a vehicle height change force for changing the vehicle height may be executable.

  (3) The vehicle suspension according to (2), wherein the control device is configured to execute the propulsive force control in a state where the plurality of energization terminals of the second electromagnetic motor are open. system.

  In a state where a plurality of energization terminals are opened, even if the absorber is operated by an external input, the motor force that depends on the electromotive force of the second motor, that is, the resistance force is not generated. . Therefore, according to the aspect described in this section, it is possible to prevent the propulsive force generated by the absorber from being reduced by the second motor when the propulsive force control is executed.

  (4) The control device according to any one of (1) to (3), wherein the control device includes a drive circuit that is disposed between the first electromagnetic motor and a power source and adjusts a current flowing through the first electromagnetic motor. The vehicle suspension system according to any one of the above.

  For the “drive circuit” described in this section, for example, a so-called inverter can be employed. According to this aspect, the first motor can be controlled and driven easily and accurately by controlling the operation of switching elements such as FETs provided for each phase of the first motor.

  (5) The control device includes a conduction / open state switching device that switches between a state in which the plurality of energization terminals included in the second electromagnetic motor are in conduction and a state in which the conduction terminals are open (1 The vehicle suspension system according to any one of items) to (4).

  The mode described in this section is a mode effective for the mode in which the propulsive force control is executed in a state where the energization terminals of the second motor are opened, and the state of the second motor can be easily switched. is there. For example, a switch that opens and closes the current-carrying terminals can be adopted as the “conduction / open state switching device”.

  (6) The vehicle suspension system according to any one of (1) to (5), wherein the first electromagnetic motor and the second electromagnetic motor are both DC brushless motors.

  Since the DC brushless motor has good controllability, it is suitable as a power source for the electromagnetic absorber.

  (7) The first electromagnetic motor and the second electromagnetic motor are both rotary motors, and the respective rotors rotate with respect to the respective stators in accordance with the relative movement of the upper and lower springs. The vehicle suspension system according to any one of items (1) to (6).

  (8) A structure in which each stator of the first electromagnetic motor and the second electromagnetic motor has a plurality of coils corresponding to each phase of the two motors, and each rotor of the two motors has a magnet. The vehicle suspension system according to item (7).

  The modes described in the above two sections are modes in which the structures of the two electromagnetic motors are limited. However, the two electromagnetic motors may be an inner rotor type motor or an outer rotor type motor.

  (9) The vehicle suspension system according to (8), wherein the absorber has a single rotor in which a rotor of the first electromagnetic motor and a rotor of the second electromagnetic motor are integrated.

  According to the aspect described in this section, since the rotors of the two electromagnetic motors are made common, an absorber having a simplified structure is realized.

  (10) Item (9), wherein the plurality of coils included in the first electromagnetic motor and the plurality of coils included in the second electromagnetic motor are respectively arranged on a circumference located at different positions in the axial direction. The vehicle suspension system described in 1.

  The “axial direction” described in this section is specifically the rotational axis of the rotor, but may be the same as the direction in which the rotor extends and the direction in which the absorber extends depending on the structure of the absorber. The aspect described in this section is an aspect in which the configuration of the stator included in the absorber is limited. In the aspect in which the stator of the first motor and the stator of the second motor are arranged in series in the axial direction. is there. According to the aspect of this section, a system capable of executing the specific resistance control is realized using an absorber that can be configured relatively simply.

  (11) The vehicle suspension system according to (9), wherein the plurality of coils included in the first electromagnetic motor and the plurality of coils included in the second electromagnetic motor are arranged at the same position in the axial direction.

  The aspect described in this section is an aspect in which the configuration of the stator included in the absorber is limited. According to the aspect described in this section, by arranging the coils of the two electromagnetic motors on the same circumference, the configuration as if the stator of the absorber is single, that is, the absorber is It is possible to adopt a configuration as if a single motor is included.

  (12) The vehicle according to (11), wherein each of the plurality of coils included in the second electromagnetic motor is disposed between two of the plurality of coils included in the first electromagnetic motor. Suspension system.

  The aspect described in this section is an aspect in which, for example, coils of the first motor and coils of the second motor are alternately arranged. When the number of coils of the first motor and the number of coils of the second motor are different, for example, two or more of the plurality of coils of one of the first motor and the second motor are replaced with the other. It may be an aspect in which two coils are sandwiched.

  (13) Each of the plurality of coils included in the first electromagnetic motor is wound around each of a plurality of cores provided to protrude toward the rotor, and the plurality of coils included in the second electromagnetic motor include: The vehicle suspension system according to (11), wherein the suspension system is wound around a plurality of cores among the plurality of cores.

  The mode described in this section is a mode in which both coils of two electromagnetic motors are wound around one core. The aspect of this term may be an aspect in which the coil of the second motor is wound around all of the plurality of cores, or may be an aspect in which the coil is wound around a part of the plurality of cores. . In addition, in the aspect of this section, for example, the number of turns including the number of turns of the coil of the first motor and the number of turns of the coil of the second motor is standard when an electromagnetic absorber having only one electromagnetic motor is designed. A mode that is configured to be the same as the number of turns of the motor coil (standard number of turns), the number of turns of the coil of the first motor is the standard number of turns, and in this state, the space remaining in the stator is used to make the second motor It is possible to adopt a mode in which a coil is wound. According to the aspect of this section, the stator included in the absorber becomes compact, and a system capable of executing the specific resistance control using the compact absorber is realized.

  (14) Each of the plurality of coils of the second electromagnetic motor is wound at a position farther from the rotor than the coil of the first electromagnetic motor wound around each of the coils (13). The vehicle suspension system according to item.

  The mode described in this section is a mode suitable for an inner rotor type motor. Specifically, in the stator of the inner rotor type motor, a space can be secured between the cores as the distance from the rotor increases, so that the coil of the second motor can be wound using the space.

  (15) Any one of (8) to (14), wherein the number of turns of each of the plurality of coils included in the second electromagnetic motor is less than the number of turns of each of the plurality of coils included in the first electromagnetic motor. The vehicle suspension system described in 1.

  When the number of turns of the coil is reduced, the inductance of the coil is generally reduced, and the time constant of the motor having the coil is reduced. That is, according to the aspect of this section, since the time constant of the second motor is reduced, a decrease in the force generated by the second motor is suppressed in a region where the stroke speed is high. It is possible to suppress or prevent power shortage.

  (16) The absorber includes a male screw portion provided on one of the spring upper portion and the spring lower portion, and a female screw portion provided on the other of the spring upper portion and the spring lower portion and screwed into the male screw portion. The male screw part and the female screw part are structured to rotate relative to each other in accordance with the relative movement of the spring upper part and the spring unsprung part, and the first electromagnetic motor and the second electromagnetic motor rotate the male screw part and the female screw part relative to each other. The vehicle suspension system according to any one of items (1) to (15), which is configured to generate a force to be generated.

  The aspect described in this section is an aspect in which the electromagnetic absorber is limited to a so-called screw mechanism. In this aspect, when a rotary motor is employed as the electromagnetic motor, it is possible to easily convert the rotational force of the motor into a damping force with respect to a stroke operation. In the aspect of this section, it is arbitrary whether the male screw part is provided in the upper part of the spring or the unsprung part, and the female screw part is provided in any of them. Furthermore, the male screw portion may be configured to be non-rotatable and the female screw portion may be configured to rotate. Conversely, the female screw unit may be configured to be non-rotatable and the male screw unit configured to be rotatable.

  Hereinafter, embodiments of the claimable invention and modifications thereof will be described in detail with reference to the drawings. In addition to the following examples, the claimable invention is implemented in various modes including various modifications and improvements based on the knowledge of those skilled in the art, including the mode described in the above [Aspect of the Invention] section. can do.

≪Suspension system configuration≫
FIG. 1 schematically shows a vehicle suspension system 10 that is an embodiment of the claimable invention. The suspension system 10 includes four independent suspension type suspension devices corresponding to the front, rear, left and right wheels 12, each of which is a spring absorber in which a suspension spring and a shock absorber are integrated. Assy20. The wheel 12 and the spring absorber assembly 20 are generic names, and when it is necessary to clarify which of the four wheels corresponds, as shown in FIG. In some cases, FL, FR, RL, and RR are attached to the front wheel, the right front wheel, the left rear wheel, and the right rear wheel.

  As shown in FIG. 2, the spring absorber assembly 20 is provided between a suspension lower arm 22 that holds the wheel 12 and constitutes a part of the unsprung part, and a mount part 24 that is provided on the vehicle body and constitutes a part of the unsprung part. The actuator 26 is an electromagnetic absorber disposed so as to connect them, and an air spring 28 as a suspension spring provided in parallel therewith.

  The actuator 26 includes an outer tube 30 and an inner tube 32 that fits into the outer tube 30 and protrudes upward from the upper end portion of the outer tube 30. The outer tube 30 is connected to the lower arm 22 via a mounting member 34 provided at the lower end portion thereof, while the inner tube 32 is connected to the mount portion 24 at a flange portion 36 formed at the upper end portion thereof. ing. The outer tube 30 is provided with a pair of guide grooves 38 on the inner wall surface thereof so as to extend in the direction in which the axis of the actuator 26 extends (hereinafter sometimes referred to as “axial direction”). Each of a pair of keys 40 attached to the lower end of the inner tube 32 is fitted into each of the outer tube 30 and the inner tube 32 by the guide groove 38 and the key 40. Relative rotation is impossible and relative movement is possible in the axial direction. Incidentally, a seal 42 is attached to the upper end portion of the outer tube 30 to prevent air leakage from the pressure chamber 44 described later.

  The actuator 26 includes a screw rod 50 as a male screw portion in which a thread groove is formed, and a nut 52 as a female screw portion that holds the bearing ball and is screwed with the screw rod 50. A mechanism and an electromagnetic motor 54 as a power source (hereinafter sometimes simply referred to as “motor 54”) are provided. The motor 54 is fixedly accommodated in the motor case 56, and the flange portion of the motor case 56 is fixed to the upper surface side of the mount portion 24, and the flange portion 36 of the inner tube 32 is attached to the flange portion of the motor case 56. By being fixed, the inner tube 32 is connected to the mount portion 24 via the motor case 56. A motor shaft 58 that is a rotation shaft of the motor 54 is integrally connected to the upper end portion of the screw rod 50. That is, the screw rod 50 is disposed in the inner tube 32 with the motor shaft 58 extended, and is rotated by the motor 54. On the other hand, the nut 52 is fixedly supported on the upper end portion of the nut support cylinder 60 attached to the inner bottom portion of the outer tube 30 in a state of being screwed with the screw rod 50.

  FIG. 3 is a plan sectional view of the motor 54 (AA section in FIG. 2). A plurality of permanent magnets 72 functioning as rotors are attached to the outer periphery of the motor shaft 58 of the motor 54 in the housing 70 of the motor 54. Strictly speaking, six magnets 72 are arranged so that the polarities are alternately changed. A plurality (9) of cores 74 projecting toward the permanent magnet 72 are formed integrally with the motor housing 70 on the inner peripheral portion of the motor housing 70. Each of the plurality of first coils 76 is wound around each of the plurality of cores 74, and each of the plurality of second coils 78 is disposed at a position away from the permanent magnet 72 from above the first coil 76. Is wound. Therefore, the stator includes the plurality of cores 74, the plurality of first coils 76, and the plurality of second coils 78.

  Due to the above structure, the actuator 26 includes a first electromagnetic motor 90 including the first coil 76 and the permanent magnet 72, a second coil 78 and the permanent magnet 72. An electromagnetic motor 92 is provided. The permanent magnet 72 functions as a rotor for both the first motor 90 and the second motor 92, and the actuator 26 has a single rotor. Further, the first coil 76 and the second coil 78 are arranged at the same position in the rotational axis direction of the rotor (hereinafter referred to as the “axial direction” because it coincides with the direction in which the axis of the actuator 26 extends). Has been. That is, the two motors 90 and 92 are configured as if they were one motor. With such a configuration, the actuator 26 of the present system 10 has two motors 90 and 92, but is very compact.

  The air spring 28 includes a housing 100 fixed to the mount portion 24, an air piston 102 fixed to the outer tube 30 of the actuator 26, and a diaphragm 104 connecting them. The housing 100 has a generally cylindrical shape with a lid, and is fixed to the lower surface side of the mount portion 24 on the upper surface side of the lid portion 106 in a state where the inner tube 32 of the actuator 26 is passed through a hole formed in the lid portion 106. Yes. The air piston 102 has a generally cylindrical shape, and is fixed to the upper portion of the outer tube 30 with the outer tube 30 fitted therein. The housing 100 and the air piston 102 are connected by a diaphragm 104 while maintaining airtightness, and a pressure chamber 44 is formed by the housing 100, the air piston 102, and the diaphragm 104. The pressure chamber 44 is filled with compressed air as a fluid. With such a structure, the air spring 28 elastically supports the lower arm 22 and the mount portion 24, that is, the wheel 12 and the vehicle body, by the pressure of the compressed air.

  From the structure as described above, when the spring upper portion and the spring lower portion approach and separate from each other, the outer tube 30 and the inner tube 32 can be relatively moved in the axial direction. Along with the relative movement, the screw rod 50 and the nut 52 relatively move in the axial direction, and the screw rod 50 rotates with respect to the nut 52. The motor 54 can apply a rotational torque to the screw rod 50, and with this rotational torque, it is possible to generate a resistance force that prevents the stroke operation of the spring top and the spring bottom. ing. The actuator 26 functions as a so-called absorber (also referred to as “damper”) by causing this resistance force to act as a damping force against the stroke motion of the sprung portion and the unsprung portion. In other words, the actuator 26 has a function of imparting a damping force to the relative motion between the sprung portion and the unsprung portion by an actuator force that is an axial force generated by the actuator 26 itself. The actuator 26 also has a function of causing the actuator force to act as a driving force, that is, a driving force with respect to the relative motion between the spring top and the spring bottom. With this function, it is possible to execute skyhook control in which a damping force proportional to the sprung absolute speed is applied. Further, the actuator 26 positively changes the distance between the sprung portion and the unsprung portion in the vertical direction (hereinafter sometimes referred to as “distance between sprung springs”) by the actuator force, It also has a function of maintaining the distance at a predetermined distance. With this function, it is possible to effectively suppress the roll of the vehicle body at the time of turning, the pitch of the vehicle body at the time of acceleration / deceleration, and the adjustment of the vehicle height of the vehicle.

  The suspension system 10 is a fluid inflow / outflow device for inflowing / outflowing air (air) as a fluid to / from an air spring 28 of each spring / absorber assembly 20, more specifically, a pressure chamber 44 of the air spring 28. An air supply / discharge device 110 that is connected and supplies air to the pressure chamber 44 and discharges air from the pressure chamber 44 is provided. Although detailed description is omitted, the suspension system 10 can adjust the air amount in the pressure chamber 44 of each air spring 28 by the air supply / discharge device 110. The spring length of the air spring 28 can be changed to change the distance between the sprung springs for each wheel 12. Specifically, it is possible to increase the amount of air in the pressure chamber 44 to increase the distance between the sprung springs and decrease the amount of air to decrease the distance between the sprung springs.

  In the present suspension system 10, the suspension electronic control unit (ECU) 140 operates the spring absorber assembly 20, that is, controls the actuator 26 and the air spring 28. Specifically, the operation of the motor 54 of the actuator 26 and the operation of the air supply / discharge device 110 is controlled. The ECU 140 is a controller 142 composed mainly of a computer having a CPU, ROM, RAM, etc., a driver 144 as a drive circuit of the air supply / discharge device 110, and a drive circuit corresponding to the first motor 90 of each actuator 26. Inverter 146, a switch 147 for opening and closing between energization terminals of the second motor 92 included in each actuator 26, and the like. The inverter 146 is connected to the battery 150 via the converter 148, and power is supplied to the first motor 90 of each actuator 26 from a power source including the converter 148 and the battery 150. Since the first motor 90 is driven at a constant voltage, the amount of power supplied to the first motor 90 is changed by changing the amount of supplied current.

The vehicle includes an ignition switch [I / G] 160, a vehicle speed sensor [v] 162 for detecting a vehicle traveling speed (hereinafter sometimes abbreviated as “vehicle speed”), and a sprung unsprung state for each wheel 12. Four stroke sensors [St] 164 for detecting the distance, a vehicle height change switch [HSw] 166 operated by the driver for the vehicle height change instruction, an operation angle sensor [δ for detecting the operation angle of the steering wheel 170, longitudinal acceleration sensor [Gx] 172 that detects actual longitudinal acceleration that is the longitudinal acceleration actually generated in the vehicle body, and lateral acceleration sensor [Gy] 174 that detects actual lateral acceleration that is the lateral acceleration actually generated in the vehicle body four vertical acceleration sensors [Gz _U] 176 for detecting a longitudinal acceleration (vertical acceleration) of the vehicle body of the mount portion 24 corresponding to the wheels 12, the wheels 1 Four vertical acceleration sensor for detecting a longitudinal acceleration of the [Gz _L] 178, a throttle sensor [Sr] 180 for detecting an accelerator opening of the throttle, the brake pressure sensor [Br] 182 for detecting a master cylinder pressure of the brake, the motor 54 A resolver [θ] 184 for detecting the rotation angle of the rotor is provided, and these are connected to the controller 142. The ECU 140 controls the operation of the spring absorber assembly 20 based on signals from these switches and sensors. Incidentally, the character [] is a symbol used when the above-mentioned switch, sensor, etc. are shown in the drawing. The ROM of the computer of the controller 142 stores a program related to the control of the actuator 26 described later, various data, and the like.

≪Resistance by motor≫
As shown in FIG. 4, each of the two motors 90 and 92 of each actuator 26 is a three-phase DC brushless motor in which coils are star-connected (Y-connected). As described above, the first motor 90 is The second motor 92 is controlled and driven by an inverter 146, and a switch 147 opens and closes between energization terminals. The inverter 146 is a general one as shown in the figure, corresponds to each of the high side (high potential side) and the low side (low potential side), and is the three phases of the first motor 90. Six switching elements HUS, HVS, HWS, LUS, LVS, and LWS corresponding to the U phase, V phase, and W phase are provided. The controller 142 of the ECU 140 determines a rotation angle (electrical angle) by a resolver 184 provided in the motor 54, and opens and closes the switching element based on the rotation angle. The inverter 146 drives the first motor 90 by so-called sine wave drive, and the amount of current flowing in each of the three phases of the first motor 90 changes in a sine wave shape, and the phase difference is an electrical angle. It is controlled to be different by 120 °. The inverter 146 energizes the motor 54 by PWM (Pulse Width Modulation) control, and the current flowing through the first motor 90 is changed by changing the ratio (duty ratio) between the pulse on time and the pulse off time. By changing the amount (energization current amount), the magnitude of the rotational torque generated by the first motor 90 is changed. Specifically, increasing the duty ratio increases the energizing current amount, increasing the rotational torque generated by the first motor 90. Conversely, decreasing the duty ratio decreases the energizing current amount. Thus, the rotational torque generated by the first motor 90 is reduced.

  The direction of the rotational torque generated by the first motor 90 may be the same as the direction in which the first motor 90 is actually rotating, or vice versa. When the direction of the rotational torque generated by the first motor 90 is opposite to the rotational direction of the first motor 90, in other words, when the force generated by the first motor 90 is a damping force (resistance force), It does not necessarily depend on the power supplied from the power source. More specifically, when the first motor 90 is rotated by an external force, an electromotive force is generated in the first motor 90, and the first motor 90 may generate a damping force depending on the electromotive force. There is. Note that the inverter 146 has a structure that can regenerate the power generated by the electromotive force in the battery 150. In the PWM control of the switching element, the amount of current flowing through each coil of the first motor 90 is also controlled by the electromotive force. In the case where the rotational torque Tq generated by the first motor 90 and the rotational direction are reversed. However, the magnitude of the rotational torque Tq generated by the first motor 90 is changed by changing the duty ratio. That is, the inverter 146 controls the current flowing through the coil of the first motor 90, that is, the energization current of the first motor 90, regardless of whether the current is supplied from the power source or generated by electromotive force. Thus, the force generated by the first motor 90 is controlled.

  The switch 147 is opened / closed by the controller 142 of the ECU 140, and in a closed state, the energization terminals of the second motor 92 are short-circuited, and functions as a conduction / open state switching device. Therefore, the second motor 92 does not generate a force when the current-carrying terminals are opened, and generates a damping force depending on the electromotive force for the stroke operation when the current-carrying terminals are short-circuited. .

FIG. 5 shows the rotational speed-torque characteristics of the motor 54. This graph shows the relationship between the rotational speed ω of the rotor of the motor 54 and the rotational torque Tq that can be generated, that is, the stroke speed V _St that is the speed of the stroke operation and that can be generated for the stroke operation. It shows the relationship with the force F _M (which may be considered as the rotational torque Tq). The characteristic line in FIG. 5 shows the case where the force that can be generated with respect to the stroke operation (hereinafter sometimes referred to as “motor force”) is in the bounce direction, and the motor force is in the rebound direction. The characteristic line in the case is omitted because it is point-symmetric with respect to the origin in the case of the bound direction.

A one-dot chain line in FIG. 5 is a characteristic line showing the force F _M1 that can be generated by the first motor 90. As can be seen by paying attention to this line, when the damping force is generated by the first motor 90, the damping force that can be generated increases the stroke speed V _St while the stroke speed V _St is relatively small. However, if the stroke speed V _St increases to some extent, the stroke speed V _St decreases as the stroke speed V _St increases due to the influence of the time constant of the first motor 90 and the like. 5 is a characteristic line indicating the force F _M2 that can be generated by the second motor 92, and this line is a characteristic line when the current-carrying terminals of the second motor 92 are short-circuited, so-called. It is a short circuit characteristic line. Therefore, the sum of the force that can be generated by the first motor 90 and the force that can be generated by the second motor 92, that is, the actuator force F _MAX that can be generated by the actuator 26 is a characteristic as shown by the solid line in FIG. It becomes. According to the present system 10, when the stroke speed is high, the force generated by the second motor 92 can compensate for the decrease in the damping force generated by the first motor 90, and the attenuation when the stroke speed is high. The lack of power will be suppressed or prevented.

  Incidentally, the broken line in FIG. 5 is a short-circuit characteristic line of the first motor 90, and the second motor 92 has a large rotational torque in a relatively high rotational range, as can be seen by comparing it with that of the second motor 92. The motor is capable of generating Therefore, in the present system 10, the first motor 90 is a low turning point type motor, and the second motor 92 is a high rotation type motor.

≪Control of suspension system≫
In the present suspension system 10, each of the four spring absorber assemblies 20 can be controlled independently. In each of the spring absorber assemblies 20, the actuator force of the actuator 26 is independently controlled to control the vibration of the vehicle body and the wheel 12, that is, the control for damping the sprung vibration and the unsprung vibration (hereinafter referred to as “vibration damping”). May be referred to as “control”). In addition, control for suppressing the roll of the vehicle body caused by turning of the vehicle (hereinafter sometimes referred to as “roll suppression control”), control for suppressing the pitch of the vehicle body caused by acceleration / deceleration of the vehicle (hereinafter referred to as “roll control”). (Sometimes referred to as “pitch suppression control”). In the vibration damping control, roll suppression control, and pitch suppression control, the target actuator force is determined by adding the vibration damping component, roll suppression component, and pitch suppression component, which are components of the actuator force for each control. It is executed comprehensively by being controlled to generate the target actuator force. In the following description, the actuator force and its component are positive values corresponding to the force in the direction (rebound direction) separating the sprung portion and the unsprung portion, and the direction causing the sprung portion and the unsprung portion to approach each other. It is assumed that the one corresponding to the force in the (bound direction) is a negative value.

  In the suspension system 10, the air spring 28 is used to control the vehicle height based on the driver's intention for the purpose of dealing with a rough road (hereinafter referred to as “vehicle height change control”). Is executed). The vehicle height change control will be briefly described. The vehicle height change control is executed when a target set vehicle height that is a set vehicle height to be realized by an operation of the vehicle height change switch 166 based on the driver's intention is changed. A sprung unsprung distance as a target for each wheel 12 is set according to each of the target set vehicle heights, and a sprung spring for each wheel 12 is set based on a detection value of the stroke sensor 164. The operation of the air supply / discharge device 110 is controlled so that the lower distance becomes the target distance, and the unsprung distance between the springs of each wheel 12 is changed to a distance corresponding to the target set vehicle height. Further, in this vehicle height change control, so-called auto leveling control is also performed for the purpose of dealing with changes in vehicle height due to, for example, changes in the number of passengers and changes in the load capacity of luggage.

i) Vibration damping control In the vibration damping control, a vibration damping component F _V of the actuator force is determined so as to generate an actuator force having a magnitude corresponding to the vibration speed in order to attenuate the vibration of the vehicle body and the wheel 12. . Specifically, the vertical movement speed of the vehicle body mount portion 24 calculated from the vertical acceleration detected by the vertical acceleration sensor 176 provided on the vehicle body mount portion 24, the so-called sprung speed V _U, and the lower arm On the basis of the vertical movement speed of the wheel 12 calculated from the vertical acceleration detected by the vertical acceleration sensor 178 provided at 22, so-called unsprung speed V _L , the vibration damping component F _V is expressed by the following equation: Calculated.
F _V = C _U・ V _U −C _L・ V _L
Here, C _U is a gain for generating a damping force corresponding to the vertical operating speed of the mount 24 of the vehicle body, and C _L is a damping force corresponding to the vertical operating speed of the wheel 12. It is a gain for generating. That is, C _U and C _L can be considered as damping coefficients for so-called sprung and unsprung absolute vibrations.

ii) Roll restraint control When the vehicle turns, the roll moment resulting from the turn causes the sprung portion on the turning inner ring side to be separated from the unsprung portion, and the sprung portion on the turning outer ring side to move closer to the unsprung portion. It is done. In the roll suppression control, in order to suppress the separation on the turning inner ring side and the approach on the turning outer ring side, the actuator force in the bounce direction is applied to the actuator 26 on the turning inner ring side, and the actuator force in the rebound direction is applied to the actuator 26 on the turning outer ring side. Each is generated as a roll restraining force. Specifically, first, as a lateral acceleration indicating the roll moment received by the vehicle body, an estimated lateral acceleration Gyc estimated based on the steering angle δ of the steering wheel and the vehicle speed v, and a lateral acceleration sensor 174 were measured. Based on the actual lateral acceleration Gyr, a control lateral acceleration Gy ^* , which is a lateral acceleration used for control, is determined according to the following equation.
Gy ^* = K ₁ · Gyc + K ₂ · Gyr (K ₁ , K ₂ : gain)
Such based on the determined control-use lateral acceleration Gy ^*, the roll restraining force component F _R is determined according to the following equation.
F _R = K ₃ · Gy ^* (K ₃ : Gain)

iii) Pitch suppression control For the nose dive of the vehicle body that occurs during deceleration, such as when braking the vehicle body, the sprung moment causing the nose dive brings the front spring side and the unsprung part closer together, The sprung part on the ring side and the unsprung part are separated from each other. In addition, for the squat of the vehicle body generated during the acceleration of the vehicle body, the sprung moment that generates the squat separates the front wheel side spring top and the spring bottom, and the rear wheel side spring top and spring bottom. Is approached. In the pitch suppression control, the actuator force is generated as the pitch suppression force in order to suppress the approach / separation distance in those cases. Specifically, as longitudinal acceleration indicative of the pitch moment acting on the vehicle body, is employed the actual longitudinal acceleration Gx that is actually measured by the longitudinal acceleration sensor 172, and based on the actual longitudinal acceleration Gx, the pitch restraining force component F _P is the following Determined according to the formula.
F _P = K ₄ · Gx (K ₄ : Gain)
It should be noted that the pitch suppression control is executed when the throttle opening detected by the throttle sensor 180 or the master cylinder pressure detected by the brake pressure sensor 182 exceeds a set threshold.

iv) Determination of target actuator force The actuator 26 is controlled based on a target actuator force which is an actuator force that should be generated. In detail, as described above, the vibration damping component F _V of the actuator force, a roll restrain component F _R, the pitch restrain component F _P is determined on the basis of their, the actuator force as a target in accordance with the following equation F ^* Is determined.
F ^* = F _V + F _R + F _P

v) Operation control of each motor Since the actuator force generated by the actuator 26 depends on the sum of the forces generated by the two motors 90 and 92, the force generated by each motor 90 and 92 is controlled. Specifically, it is determined whether the energization terminals of the second motor 92 are short-circuited or opened, and the target actuator force F ^* is generated according to the force generated by the second motor 92 in that case. In addition, the force generated by the first motor 90 is controlled.

a) Specific resistance force control When the force generated in the actuator 26 is a resistance force with respect to the relative motion between the spring top and the spring bottom, the ECU 140 causes the current-carrying terminals of the second motor 92 to be short-circuited and in that state The resistance force generated by the actuator 26 is controlled by controlling the energization current flowing through the first motor 90. That is, the specific resistance control is executed by the ECU 140. Specifically, the switch 147 is closed and the energization terminals of the second motor 92 are short-circuited. Next, in this case, the resistance force F ₂ generated by the second motor 92 is estimated according to the stroke speed V _St that is the relative speed between the spring top and the spring bottom. Specifically, the ROM of the ECU 140 stores map data of the rotational torque Tq (resistance force) using the stroke speed V _St indicated by the two-dot chain line in FIG. 5 as a parameter. The resistance force F ₂ of the motor 92 is estimated. Next, on the basis of the estimated resistance force of the second motor 92, the target energization current i ₁ ^{* of} the first motor 90 is determined according to the following equation.
i ₁ ^* = K ₅ · (F ^* −F ₂ ) (K ₅ : gain)
Based on the determined target energization current amount i ₁ ^* , a target duty ratio is determined, and a command based on the duty ratio is transmitted to the inverter 146. The inverter 146 drives the first motor 90 so as to generate a motor force corresponding to the target energization current amount i ₁ ^* under the appropriate duty ratio. By the operation control of the first motor 90 and the second motor 92 as described above, the actuator 26 generates an actuator force that becomes the target actuator force F ^* .

b) Propulsive force control When the force generated by the actuator 26 is a propulsive force for the relative movement between the spring upper part and the spring unsprung part, the ECU 140 causes the switch 147 to be in an open state and Opened. In this case, since the force generated by the second motor 92 is 0, the target energization current amount i ₁ ^{* of} the first motor 90 is determined based on the target actuator force F ^* .

≪Actuator control flow≫
The actuator 26 as described above is controlled by the actuator control program shown in the flowchart of FIG. 6 at a short time interval (for example, several milliseconds to several tens of milliseconds) while the ignition switch 160 is in the ON state. It is performed by being repeatedly executed by 142. The control flow will be briefly described below with reference to the flowchart shown in the figure. The actuator control program is executed for each actuator 26 of the spring absorber assembly 20 provided on each of the four wheels 12. In the following description, processing by this program for one actuator 26 will be described in consideration of simplification of description.

In this program, first, in steps 1 (hereinafter abbreviated as “S1”, other steps are the same) to S4, the vibration damping component F _V and the roll suppression component F are obtained by the method described above. and _R, and the pitch restrain component F _P is determined by summing them, the target actuator force F ^* is determined. Next, it is determined which of specific resistance control and propulsion control is to be executed. Specifically, the specific resistance force control is executed when the direction of the target actuator force and the direction of the stroke operation are opposite, and the propulsive force control is executed when they are in the same direction. Specifically, based on the sign of the product of the target actuator force F ^* and the stroke speed V _St , the specific resistance control is executed when the products are negative and zero. In S5, the stroke speed V _St is calculated by the difference between the detection value at the previous execution of the program by the stroke sensor 164 and the current detection value.

When the specific resistance control is executed, in S7, the switch 147 is closed and the energization terminals are short-circuited, and in S8, the resistance F ₂ generated by the second motor 92 in that state is It is estimated with reference to the map data according to the stroke speed V _St calculated in S5. Further, when the driving force control is executed in S9, is a state of inter-switch 147 is opened conductive terminal is opened, in S10, it is resistant F ₂ 0 of the second motor 92.

Then, in S11, based on the resistance force F ₂ of the target actuator force F ^* and the second motor 92, the target of the first motor 90 in accordance with the formula i ₁ ^* = K ₅ · the above-mentioned (F ^* -F ₂₎ The amount of energization current is determined. A duty ratio is determined based on the target energization current amount i ₁ ^* of the first motor 90 determined as described above, and a control signal corresponding to the duty ratio is transmitted to the inverter 146. After the series of processes described above, one execution of the actuator control program ends.

≪Modification≫
i) First Modification In the system of this modification, the configuration of the electromagnetic motor included in the actuator is different from the configuration of the motor 54 in the above embodiment. FIG. 7 shows a plan cross-sectional view of an electromagnetic motor 200 that is a power source of an actuator provided in the system of this modification. In the above embodiment, both the plurality of coils 76 included in the first motor 90 and the plurality of coils 78 included in the second motor 92 are wound around each of the plurality of cores 74. , Each of the plurality of second coils 78 included in the second motor 92 is interposed between each of the plurality of first coils 76 included in the first motor 90. Specifically, a plurality of cores 202 (hereinafter sometimes referred to as “first cores”) are provided in the inner peripheral portion of the motor housing 70 as in the above-described embodiment, and each of the plurality of first cores 202 is provided. In between, a plurality of second cores 204 smaller than the first core 202 are provided using the space between them. Each of the first cores 202 is wound with one of a plurality of first coils 76 constituting the stator of the first motor 90, and each of the second cores 204 constitutes a stator of the second motor 92. One of the plurality of second coils 78 is wound. By the way, in the figure, the three phases (U, V, W) of the first coil 76 are indicated by circles, and the three phases of the second coil 78 are indicated by triangles. Yes.

ii) Second Modification FIG. 8 is a plan sectional view of an electromagnetic motor 220 that is a power source of an actuator provided in a system of another modification. In the electromagnetic motor 220 of this modification, twelve cores 222 are provided, and the first coil that constitutes the stator of the first motor 90 is arranged on the six cores arranged every other one of the cores 222. 76 are wound, and the second coils 78 constituting the stator of the second motor 92 are wound around the six cores 222 existing between the cores 222 around which the first coils 76 are wound. It has been turned. That is, each of the plurality of second coils 78 included in the second motor 92 is interposed between each of the plurality of first coils 76 included in the first motor 90. In addition, the rotor of the electromagnetic motor 220 of the present embodiment is provided with four permanent magnets 72 and is a four-pole rotor.

iii) Third Modification FIG. 9 is a front sectional view of an electromagnetic motor 240 that is a power source of an actuator provided in a system of another modification. In the embodiment and the two modifications, the plurality of first coils 76 included in the first motor 90 and the plurality of second coils 78 included in the second motor 92 are disposed at the same position in the axial direction. However, in this modification, they are arranged on the circumferences located at different positions in the axial direction. Specifically, on the inner peripheral portion of the motor housing 70, a plurality of first coils 76 are arranged on the lower side, and a plurality of second coils 78 are arranged on the upper side. In this modification as well, the plurality of permanent magnets 72 attached to the outer periphery of the motor shaft 58 function as a common rotor for both the two motors 90 and 92.

iv) Effects of Modifications In the above three modifications, the two motors 90 and 92 are controlled in the same manner as in the above-described embodiments. Therefore, according to the system 10 of these three modifications, the above-described embodiments can be used. Similarly, when the stroke speed is high, the force generated by the second motor 92 can compensate for the decrease in the damping force generated by the first motor 90, and the damping force is insufficient when the stroke speed is high. It can be suppressed or prevented.

1 is a schematic diagram showing the overall configuration of a vehicle suspension system that is an embodiment of the claimable invention. It is front sectional drawing which shows the spring absorber Assy shown in FIG. FIG. 3 is a plan sectional view of the electromagnetic motor provided in the actuator of FIG. FIG. 3 is a circuit diagram of a drive circuit or the like that controls an electromagnetic motor included in the actuator of FIG. 2. It is a figure which shows the relationship between the rotational speed and rotational torque of an electromagnetic motor with which the actuator of FIG. 2 is provided. It is a flowchart showing the actuator control program performed by the suspension electronic control unit shown in FIG. It is a top sectional view of an electromagnetic motor which is a motive power source of an actuator with which a suspension system of the 1st modification is provided. It is a plane sectional view of an electromagnetic motor which is a motive power source of an actuator with which a suspension system of the 2nd modification is provided. It is front sectional drawing of the electromagnetic motor which is a motive power source of the actuator with which the suspension system of a 3rd modification is provided.

Explanation of symbols

  10: Vehicle suspension system 20: Spring absorber assembly 22: Lower arm (lower spring) 24: Mount part (spring upper part) 26: Actuator (absorber) 28: Air spring 50: Screw rod (male screw part) 52: Nut (female screw) 54): Electromagnetic motor 72: Permanent magnet (rotor) 74: Core 76: First coil 78: Second coil 90: First electromagnetic motor (DC brushless motor) 92: Second electromagnetic motor (DC brushless motor) 110: Air supply / discharge device 140: Suspension electronic control unit (control device) 146: Inverter (drive circuit) 147: Switch (conducting / opening state switcher) 148: Converter 150: Battery

Claims (8)

There are a first electromagnetic motor and a second electromagnetic motor that are arranged between the spring top and the spring bottom and operate in accordance with the relative movement between the spring top and the spring bottom, and these two electromagnetic motors generate An electromagnetic absorber that generates a resistance force relative to the relative motion of the sprung portion and the unsprung portion depending on the force;
A control device for controlling the absorber, wherein the plurality of energization terminals of the second electromagnetic motor are electrically connected to each other, and in this state, the first electromagnetic motor and a power source are connected and the first electromagnetic A vehicle suspension system comprising: a control device capable of executing a specific resistance force control for controlling the resistance force generated by the absorber by adjusting a current flowing through the motor. The absorber is capable of generating a driving force for relative movement between the sprung portion and the unsprung portion,
The control device is
By adjusting the current flowing through the first electromagnetic motor while supplying current from the power source to the first electromagnetic motor, propulsive force control for controlling the propulsive force generated by the absorber can be executed.
2. The vehicle suspension system according to claim 1, wherein the propulsive force control is executed in a state where the plurality of energization terminals of the second electromagnetic motor are opened.   The said control apparatus has a conduction | electrical_connection / open state switching device which switches the state in which the said several energization terminals which the said 2nd electromagnetic motor has conduct | electrically_connected, and the state in which these energization terminals were open | released. Item 3. The vehicle suspension system according to Item 2. The first electromagnetic motor and the second electromagnetic motor are both rotary motors, and each rotor having a magnet is moved to each phase of the two motors in accordance with the relative movement of the spring top and the spring bottom. It is structured to rotate with respect to each stator having a plurality of corresponding coils,
4. The vehicle suspension system according to claim 1, wherein the absorber has a single rotor in which a rotor of the first electromagnetic motor and a rotor of the second electromagnetic motor are integrated. 5.   5. The vehicle according to claim 4, wherein the plurality of coils included in the first electromagnetic motor and the plurality of coils included in the second electromagnetic motor are arranged on a circumference located at different positions in the axial direction. Suspension system.   The vehicle suspension system according to claim 4, wherein the plurality of coils included in the first electromagnetic motor and the plurality of coils included in the second electromagnetic motor are arranged at the same position in the axial direction.   The vehicle suspension system according to claim 6, wherein each of the plurality of coils included in the second electromagnetic motor is disposed between two of the plurality of coils included in the first electromagnetic motor.   Each of the plurality of coils included in the first electromagnetic motor is wound around each of a plurality of cores provided so as to protrude toward the rotor, and the plurality of coils included in the second electromagnetic motor includes the plurality of coils. The vehicle suspension system according to claim 6 wound around a plurality of cores.

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