JP2009214836A - Electromagnetic suspension - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic suspension capable of adequately controlling a force in the vertical direction thereof. <P>SOLUTION: A screw shaft 42 of the electromagnetic suspension 10 and an electric motor 6 are connected to each other by a rotation transmission device 8 having a continuously variable transmission. The ratio of the number of rotation of the electric motor 6 to the rotation of the screw shaft 42 is variable. For example, when a transmission gear ratio is increased when a vertical stroke speed is high, the number of rotation of the electric motor 6 can be decreased, and the force in the vertical direction can be excellently applied. Furthermore, when the transmission gear ratio is decreased during the regenerative operation of the electric motor 6, the number of rotation of the electric motor 6 can be increased, and a large electromotive force can be generated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electromagnetic suspension, and more particularly to a rotation transmission device provided between a rotating member of an electromagnetic suspension and an electric motor.

Patent Documents 1 and 2 include (a) an electric motor, (b) a screw shaft provided between a spring top and a spring bottom of a vehicle, a screw shaft, and a nut member screwed to the screw shaft, and a spring. An electromagnetic suspension is described that includes a telescopic mechanism that expands and contracts with relative movement between the upper part and the unsprung part, and (c) a rotation transmission device that is provided between the electric motor and the screw shaft and has a pair of gears. . In these electromagnetic suspensions, the transmission gear ratio ε (= ω _S / ω _M ), which is the ratio between the rotational angular velocity ω _M of the electric motor and the rotational angular velocity ω _S of the screw shaft in the rotation transmission device, is constant.
Patent Document 1 describes a rotation transmission device including a planetary gear mechanism. In this rotation transmission device, the sun gear and the rotating shaft of the electric motor are connected, the planetary gear carrier and the screw shaft are connected, and the ring gear is fixed. The speed ratio ε (= ω _S / ω _M ) in the rotation transmission device is constant.
JP 2004-11824 A JP 2005-256920 A

  An object of the present invention is to improve an electromagnetic suspension. For example, the ratio between the rotational angular velocity of a motor-side rotating shaft connected to an electric motor and the rotational angular velocity of a suspension-side rotating shaft connected to a rotating member is variable. It is to do.

Means and effects for solving the problem

The electromagnetic suspension according to claim 1 is provided between (a) an electric motor, and (b) a spring upper part and a lower part of a vehicle, and transmission of rotation between the electric motor via a rotation transmission device. A rotating member capable of rotating, and (c) a non-rotating member engaged with the rotating member so as to be able to convert between a rotational motion and a linear motion, and between the spring upper portion and the spring lower portion. An electromagnetic suspension for applying a vertical force to the motor, wherein the rotation transmission device is provided between a motor-side rotating shaft connected to the electric motor and a suspension-side rotating shaft connected to the rotating member, The present invention is characterized in that it is a variable transmission ratio type rotation transmission device in which the ratio of the rotational angular velocity of the suspension side rotational shaft to the rotational angular velocity of the motor side rotational shaft is variable.
In the electromagnetic suspension described in this section, the motor-side rotating shaft is connected to the rotating shaft (motor shaft) of the electric motor, and the suspension-side rotating shaft is connected to the rotating member. When the motor shaft of the electric motor is directly connected to the motor-side rotating shaft (the motor-side rotating shaft and the motor shaft are connected so as not to be relatively rotatable, the motor shaft and the motor-side rotating shaft are integrated. The motor side rotating shaft and the motor shaft may be connected in a relatively rotatable manner, but the motor side rotating shaft may rotate. A predetermined relationship is established between the angular velocity and the rotational angular velocity of the motor shaft of the electric motor, and these correspond one-to-one. Similarly, when the rotating member is directly connected to the suspension side rotating shaft (the suspension side rotating shaft and the rotating member are connected so as not to be relatively rotatable, the rotating member and the suspension side rotating shaft are integrally formed. In some cases) or indirectly connected via a transmission or the like (the suspension-side rotating shaft and the rotating member are connected so as to be relatively rotatable), but the suspension-side rotating shaft rotates. A predetermined relationship is established between the angular velocity and the rotational angular velocity of the rotating member, which corresponds one-to-one. The rotation transmission device is provided between the motor side rotation shaft and the suspension side rotation shaft. The output torque of the electric motor is applied to the rotating member via the rotation transmission device, whereby a vertical force is applied to the non-rotating member, and a vertical force is applied between the spring top and the spring bottom.
In the rotation transmission device for the electromagnetic suspension described in this section, the transmission gear ratio that is the ratio (ε = ω _S / ω _M ) of the rotation angular velocity ω _S of the suspension side rotation shaft to the rotation angular velocity ω _M of the motor side rotation shaft is variable. Is done. Hereinafter, in order to simplify the description in the present specification, when the motor-side rotating shaft and the motor shaft of the electric motor are directly connected and the suspension-side rotating shaft and the rotating member are directly connected, that is, the motor-side rotating It is assumed that the rotational angular velocity of the shaft is the same as the rotational angular velocity of the motor shaft of the electric motor, and that the rotational angular velocity of the suspension-side rotational shaft and the rotational angular velocity of the rotating member are the same.
For example, the absolute value of the expansion / contraction speed (corresponding to the rotational angular speed of the rotating member and the rotational angular speed of the suspension-side rotating shaft, hereinafter abbreviated as the vertical stroke speed) between the sprung part and the unsprung part is larger than the set value. rotational speed N _M of the motor, its upper limit rotation speed determined by the characteristics of the electric motor N _MAX if (synchronous speed and may be referred to) composed of large (N _M> N _MAX), by a large value the speed ratio ε For example, the rotational speed N _M of the electric motor can be made smaller than the upper limit rotational speed N _MAX (N _M <N _MAX ). As a result, an appropriate vertical force can be applied between the sprung portion and the unsprung portion. In addition, even if the absolute value of the vertical stroke speed is large, the rotation speed of the electric motor can be reduced. Therefore, the electric motor can be made smaller in the upper limit rotation speed N _MAX . Cost can be reduced.
Furthermore, by reducing the speed ratio ε than during power running operation at the time of regenerative operation, it is possible to increase the rotational speed N _X of the electric motor with respect to the absolute value of the vertical stroke speed. As a result, the electromotive force can be increased and the power storage device can be charged effectively.
The rotation transmission device transmits rotation between two rotation shafts connected to each other, and transmits rotation angular velocity and torque. Between the transmission ratio ε _ro (ω _S / ω _M ) and the torque ratio ε _tq (T _S / T _M ), the relational expression ε _ro · ε _tq = 1.
Is often established, but may not be established. For example, even if the speed ratio ε _ro changes, the torque ratio ε _tq may be constant. In the electromagnetic suspension described in this section, at least the gear ratio is variable.
In the electric motor, the rotation axis of the motor shaft of the electric motor (or the rotation axis of the motor-side rotation shaft) and the rotation axis of the rotating member (or the rotation axis of the suspension-side rotation shaft) are on the same straight line. Even if it provides, you may provide in the state which does not exist on the same straight line. When it is provided in a state that does not exist on the same straight line, it is provided in a state where the two rotation axes are in the same plane (the two rotation axes are separated from each other in parallel or the two rotation axes intersect). Or you may provide in the state (position of a twist) which two rotation axes do not exist in the same plane.
In the electromagnetic suspension, the rotating member may be a rod-shaped screw shaft, the non-rotating member may be a nut member screwed to the screw shaft, the rotating member may be a nut member, and the non-rotating member may be a screw shaft.
Furthermore, the electric motor may be a direct current motor or an alternating current motor, and may be of any kind. For example, a brushless DC motor or an induction motor can be used.

Patentable invention

  In the following, the invention that is claimed to be claimable in the present application (hereinafter sometimes referred to as “claimable invention”. The claimable invention is at least the “present invention” to the invention described in the claims. Some aspects of the present invention, including subordinate concept inventions of the present invention, superordinate concepts of the present invention, and inventions of other concepts) 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 understanding of the claimable invention, and is not intended to limit the set of components constituting the claimable invention to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, 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 constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

(1) (a) an electric motor, and (b) a rotating member provided between a sprung portion and a unsprung portion of the vehicle and capable of transmitting rotation to and from the electric motor via a rotation transmitting device; (c) The rotating member is provided with a non-rotating member engaged in a state in which a rotational motion and a linear motion can be converted, and a vertical force is applied between the spring upper portion and the spring lower portion. Electromagnetic suspension,
The rotation transmission device is provided between a motor-side rotating shaft connected to the electric motor and a suspension-side rotating shaft connected to the rotating member, and the motor-side rotating shaft has a rotation angular velocity of the suspension-side rotating shaft. An electromagnetic suspension characterized in that it is a variable transmission ratio type rotation transmission device in which the ratio of the rotation angle to the rotational angular velocity is variable.
(2) The electromagnetic suspension according to (1), wherein the electric motor is provided in a state where the line axis thereof and the rotation axis of the rotating member do not exist on the same straight line (Claim 2).
(3) The electromagnetic suspension according to (2), wherein the electric motor is provided in a state in which a rotation axis of the electric motor and a rotation axis of the rotating member are separated from each other in parallel.
Compared to the case where the electric motor is provided in a state where the rotation axis of the electric motor and the rotation axis of the rotating member are on the same straight line, the allowable stroke between the spring upper part and the spring lower part can be increased. The degree of freedom in design can be improved. In particular, it is effective in the case where there is a great design restriction to provide the same line.
The same applies to the relationship between the rotation axis of the motor-side rotation shaft and the rotation axis of the suspension-side rotation shaft. Even if the electric motor is provided in a state where these two rotation axes exist on the same straight line, they are separated from each other. You may provide in a parallel state.
(4) In the transmission ratio variable type rotation transmission device, when the absolute value of the expansion / contraction speed of the distance between the sprung portion and the unsprung portion is larger than a predetermined setting value, The electromagnetic suspension according to any one of (1) to (3), further including a high-speed movement speed ratio control unit that increases the ratio.
Setting value V _th of the absolute value of the vertical stroke speed, for example, if the gear ratio ε is the reference value, the rotational speed of the electric motor N _M is an upper limit rotation speed N _MAX is determined by the characteristics of the electric motor or the upper limit when the rotational speed less than the set rotational speed N _th, can be sized up and down stroke speed.
In this case, the reference value is the speed ratio in the rotation transmission device when the absolute value of the up / down stroke speed is equal to or less than the set value _Vth . The gear ratio when the absolute value of the vertical stroke speed is equal to or less than the set value V _th is determined in advance based on one or more of the characteristics of the electric motor, the specifications of the electromagnetic suspension, the specifications of the rotation transmission device, and the like. If the value is 1, the value may be 1.
In the electromagnetic suspension described in this section, when the absolute value of the vertical stroke speed is larger than the set value _Vth , the transmission ratio is set to a value larger than the reference value. The speed ratio ε may be a constant value or a value determined by the absolute value of the vertical stroke speed. Gear ratio ε is, for example, during normal running of the vehicle, even if a large absolute value of the vertical stroke speed, it is desirable that the rotational speed N _M of the electric motor is a size that does not exceed the upper limit rotation speed N _MAX.
Since the absolute value of the up / down stroke speed corresponds to the number of rotations of the rotating member, the absolute value of the up / down stroke speed can also be expressed by the number of rotations of the rotating member.
(5) The high speed movement speed ratio control unit includes a ratio gradually increasing unit that increases the ratio as the absolute value of the expansion / contraction speed increases when the absolute value of the expansion / contraction speed is larger than the set value ( The electromagnetic suspension described in 4).
When the absolute value of the up / down stroke speed is larger than the set value _Vth, if the speed ratio ε is increased as the absolute value of the up / down stroke speed increases, the rotation speed of the electric motor can be kept constant below the upper limit rotation speed N _MAX . or maintaining the size, rotational speed N _M of the electric motor can be or to not larger than the upper limit rotational speed N _MAX.
(6) A ratio increasing unit that makes the ratio larger than when the absolute value of the expansion / contraction speed of the distance between the sprung portion and the unsprung portion is large. The electromagnetic suspension according to any one of (1) to (5).
When the speed ratio ε is large, the number of rotations of the electric motor with respect to the absolute value of the vertical stroke speed can be made smaller than when the speed ratio ε is small. As a result, the ability of the switching circuit for controlling the electric motor and the ability of the computer can be reduced, and the cost can be reduced accordingly.
(7) The speed ratio variable type rotation transmission device includes a regenerative operation speed ratio control unit that reduces the ratio when the electric motor is in a regenerative operation state than in a powering operation state. The electromagnetic suspension as described in any one of thru | or (6) term (Claim 5).
Electromotive force generated by an electric motor to a case of operating as a generator, since the rotational speed magnitude corresponding to of the electric motor (induction), regenerative operation, the row when the rotation speed N _M of the electric motor is large It is better to be
Therefore, at the time of regenerative operation, to reduce the speed ratio epsilon, it is that reasonable to increase the rotational speed N _M of the electric motor with respect to the absolute value of the vertical stroke speed.
In addition, the regenerative operation can be performed in a region where the regenerative operation has not been performed due to the low rotation speed of the electric motor.
In the electromagnetic suspension described in this section, when the speed ratio ε is the reference value during the power running operation, the value is smaller than the reference value during the regenerative operation.
The feature described in this section can be applied not only when the electric motor is in the regenerative operation state but also when it is desirable to apply a damping force to the suspension. For example, it is desirable to increase the rotation speed of the electric motor not in a state where positive vertical force is applied but in a short circuit state, a state functioning as a generator, a power generation braking state, or the like.
(8) When the power storage amount stored in the power storage device, which is the power source of the electric motor, is less than or equal to a predetermined set amount, the electromagnetic suspension is configured so that the decreasing slope of the power storage amount is a predetermined set gradient. The electromagnetic suspension according to item (7), including an electric motor control unit that performs the regenerative operation in at least one of the cases described above.
When the amount of power stored in the power storage device is equal to or less than a predetermined set amount, it is desirable to stop the control of the vertical force by the electric motor and charge the power storage device. In addition, when the power storage device is common to the power source of another power consuming device (for example, a drive motor) mounted on the vehicle, in a state where power is supplied to the other power consuming device, There is a case where the amount of stored electricity increases and decreases at a set gradient or more. In this case, it is desirable that charging is performed by regenerative operation of the electric motor of the electromagnetic suspension.
(9) The electromagnetic suspension obtains a charge request level in the power storage device based on at least one of a power storage amount stored in a power storage device that is a power source of the electric motor and a decrease rate of the power storage amount. The electromagnetic suspension according to any one of items (1) to (8), further including a charge request corresponding speed change ratio determining unit that reduces the ratio when the degree of the charge request is strong when compared with the weak case.
If the ratio is reduced, such as when the amount of power stored in the power storage device is large or when it is predicted that the power will be insufficient, the rotational speed of the electric motor relative to the absolute value of the vertical stroke speed at that time will be increased. And regenerative efficiency can be increased.
(10) The variable transmission ratio rotation transmission device includes: (i) a variable pulley connected to the motor-side rotation shaft and the suspension-side rotation shaft, respectively, and a belt stretched between the pair of variable pulleys. And (ii) a groove width changing portion for changing the width of the belt by changing the width of the V-shaped groove of the pair of variable pulleys. (1) to (9) The electromagnetic suspension as described in any one of Claims (Claim 6).
In the continuously variable transmission mechanism, the gear ratio ε is expressed by the following equation: ε = R _M / R _S = ω _S / ω _M = T _M / T _S
Can be expressed as
R _M and R _S are the belt engagement diameter of the variable pulley connected to the motor-side rotation shaft and the belt engagement diameter of the variable pulley connected to the suspension-side rotation shaft, respectively, and T _M and ω _M are Torque and rotational angular velocity applied to the motor-side rotating shaft, and T _S and ω _S are torque and rotational angular velocity applied to the suspension-side rotating shaft. In the continuously variable transmission mechanism, the product of the transmission ratio (ω _S / ω _M ) and the torque ratio (T _S / T _M ) is 1.
As shown in the above equation, the gear ratio ε can be changed by changing the ratio of the contact diameters R _M and R _S of the pair of variable belts.
(11) The transmission ratio variable type rotation transmission device is provided between (i) a sun gear connected to the motor side rotation shaft, a ring gear connected to the suspension side rotation shaft, and the sun gear and the ring gear. A planetary gear mechanism including a planetary gear; and (ii) a planetary gear carrier rotation control unit that changes the ratio of the rotation angular velocity of the sun gear and the rotation angular velocity of the ring gear by controlling the rotation state of the planetary gear carrier that holds the planetary gear. The electromagnetic suspension according to any one of items (1) to (10), including:
When the planetary gear carrier is prevented from rotating in the planetary gear mechanism, the transmission ratio ε _P0 is expressed by the equation ε _P0 = −Z _M / Z _R = ω _R / ω _M = T _M / T _R
Can be expressed as
Z _M and Z _R are the number of teeth of the sun gear (electric motor side) and the number of teeth of the ring gear, respectively. T _M and ω _M are the torque and rotational angular velocity of the sun gear, and T _R and ω _R are the ring gear. Torque and rotational angular velocity. When the planetary carrier is prevented from rotating, the product of the gear ratio (ω _R / ω _M ) and the torque ratio (T _R / T _M ) between the ring gear and the sun gear is 1.
Further, when the suspension-side rotating shaft is connected directly to the ring gear, in the above formulas, Z _R, omega _R, the T _R, respectively, the number of teeth of the suspension side rotation shaft side, the rotation angular velocity of the rotating member, Torque can be used. On the other hand, when the suspension-side rotating shaft is connected to a suspension-side gear that meshes with the ring gear, the gear ratio between the ring gear and the suspension-side gear (rotating member side) is γ (−Z _R ′ / Z _S = Ω _S / ω _R ), the gear ratio ε (ratio of the rotational angular velocity ω _S of the suspension-side rotary shaft to the rotational angular velocity ω _M of the motor-side rotary shaft) in the rotation transmission device is expressed by the equation ε = ε _P0 · γ
It will be represented by When the suspension side gear meshes with the outer peripheral side of the ring gear, Z _R ′ is the number of teeth on the outer peripheral side (suspension side) of the ring gear, and Z _R is the number of teeth on the inner peripheral side (planetary gear side) of the ring gear. It becomes.
In the present specification, the rotational angular velocity ω and the torque T each have a direction and a magnitude, and the signs (positive and negative) represent the rotational direction of the rotating shaft and the direction of the torque. When the planetary gear carrier is fixed, the direction of rotation is reversed between the ring gear and the sun gear.
When the planetary gear carrier provoking rotation (planetary gear revolves), the rotational angular velocity omega _RY of the ring gear, when the rotational angular velocity of the planetary gear carrier and the omega _C, wherein _{ω RY = - (Z M /} Z R) (ω _MY −ω _C ) + ω _C = ε _P0 (ω _MY −ω _C ) + ω _C
Can be expressed as The rotational angular velocity when the planetary gear is revolving is distinguished by adding a subscript Y. The ring gear torque T _M is
T _R = T _M / ε _P0
Can be expressed as
The gear ratio ε _Y when the planetary gear is revolved is
ε _Y = ω _RY / ω _MY = − (Z _M / Z _R ) {1−ω _C / ω _MY } + ω _C / ω _MY
It becomes.
From these equations, when the planetary gear carrier is rotated in the same direction as the sun gear (electric motor), the absolute value of the rotational angular velocity of the ring gear is smaller than that when the planetary gear carrier is fixed, and the gear ratio ε The absolute value of _Y becomes smaller. Further, when the planetary gear carrier is rotated in the opposite direction to the sun gear, the absolute value of the rotational angular velocity of the ring gear is increased, and the absolute value of the speed ratio ε _Y is increased.
In this case, since the torque ratio (1 / ε _P0 ) is constant, the product of the speed ratio ε _Y and the torque ratio (1 / ε _P0 ) is not 1.
The gear ratio ε _Y can also be changed by switching between a state where the rotation of the planetary gear carrier is allowed and a state where it is blocked. When the rotation of the planetary gear carrier is free, the rotation angular velocity ω _{R of the} ring gear is 0, and in the state where the rotation is blocked, the rotation angular velocity ω _R is ε _P0 · ω _M , and the tolerance is adjusted. The rotation angular velocity ω _{R of the} ring gear can be set to an intermediate value between them.
(12) When the planetary gear carrier rotation control unit changes the vehicle height, which is a relative position of the spring upper part to the spring unsprung part, by controlling the rotation state of the planetary gear carrier, the change in vertical force The electromagnetic suspension according to item (11), further including a vehicle height control unit that controls a relationship between a speed and a change speed of the vehicle height.
In the planetary gear mechanism, as described above, even if the planetary gear carrier is rotated or prevented from rotating, the ratio of the ring gear torque to the sun gear torque is constant, whereas the planetary gear carrier is rotated. The ratio between the rotational angular velocity of the ring gear and the rotational angular velocity of the sun gear varies depending on whether or not the rotation is prevented. Therefore, by controlling the rotation state of the planetary gear carrier, the relationship between the rotation angular velocity of the ring gear and the change in torque can be controlled even if the change in the rotation angular velocity and torque of the sun gear is constant. It is possible to control the relationship between the vertical stroke speed between the spring and the unsprung part and the change speed of the vertical force applied between them.
(13) In the transmission ratio variable type rotation transmission device, when the absolute value of the expansion / contraction speed of the distance between the sprung portion and the unsprung portion is larger than a predetermined set speed, the ratio is determined in advance. The electromagnetic suspension according to any one of items (1) to (12), including a high-speed expansion / contraction speed ratio determining unit that is larger than a set value corresponding to the expansion / contraction speed.
Stretching speed corresponding setting value is in a normal running state of the vehicle, the absolute value of the upper and lower stroke speed is even set speed over a predetermined rotation speed N _M of the electric motor is equal to or less than the upper limit rotation speed N _MAX or the size, rotational speed N _M of the electric motor can, etc. or to the size of the desired size.
The speed ratio ε can be a predetermined fixed value larger than the set value corresponding to the expansion / contraction speed, or a value determined by the absolute value of the up / down stroke speed.
(14) A regenerative operation speed ratio determining unit that sets the ratio to a value smaller than a preset value corresponding to a regenerative operation when the electric motor is in a regenerative operation state. The electromagnetic suspension according to any one of (1) to (13).
The regenerative operation setting value is, for example, a large value at which the rotation speed of the electric motor is equal to or higher than the set rotation speed suitable for the regenerative operation even when the absolute value of the vertical stroke speed is equal to or less than the set speed in the normal traveling state of the vehicle. It can be.

Hereinafter, an electromagnetic suspension according to an embodiment of the present invention will be described in detail with reference to the drawings. In FIG. 1, the electromagnetic suspension includes a vertical force generator 4, an electric motor 6, a rotation transmission device 8, and the like.
The vertical force generator 4 is provided between the lower arm 12 and the vehicle body (the upper part of the tire housing) 14 for each of the front, rear, left and right wheels of the vehicle. The lower arm 12 is a member that holds the wheel and constitutes the unsprung portion, and the vehicle body 14 is a member that constitutes the unsprung portion. Hereinafter, the lower arm 12 may be referred to as an unsprung portion, and the vehicle body 14 may be referred to as an unsprung portion.
Further, a vertical force generator 4 and a hydraulic shock absorber 16 are provided in series between the spring lower portion 12 and the spring upper portion 14, and an air spring 18 as a suspension spring is connected to the vertical force generator 4. And in parallel with the hydraulic shock absorber 16. In this embodiment, an electromagnetic suspension expansion / contraction mechanism 20 is constituted by the vertical force generator 4, the hydraulic shock absorber 16, the air spring 18, and the like.
Further, the electric motor 6 is provided at a position of the vehicle body 14 separated from the position where the vertical force generator 4 is provided, with the respective axes L _M and L _S being parallel to each other. The electric motor 6 is provided separately and independently from the vertical force generator 4. The electric motor 6 and the rotation transmission device 8 are held by a housing (not shown) and fixed to the vehicle body 14.

The air spring 18 is provided on the outer peripheral side of the housing 28 of the vertical force generator 4. The air spring 18 includes a chamber shell 30, an air piston cylinder 32, and a diaphragm 34 connecting them.
The chamber shell 30 is connected to the vehicle body 14 in principle so as not to be relatively movable in the vertical direction, and the air piston cylinder 32 is fixed to a housing (hereinafter referred to as a damper housing) 36 of the hydraulic shock absorber 16. . Since the damper housing 36 is connected to the lower arm 12 in principle so as not to be relatively movable in the vertical direction, the air spring 20 is provided between the vehicle body 14 and the lower arm 12. The air piston cylinder 32 is provided in the housing 28 so as to be airtight and slidable.
The diaphragm 34 has one end fixed to the chamber shell 30 and the other end fixed to the air piston cylinder 32. The chamber shell 30, the diaphragm 34, the air piston cylinder 32, and the housing 28 serve as an air chamber (air chamber). 38 is formed.
In the present embodiment, the axis L _S direction (up and down) between the chamber shell 30 (and the housing 28) connected to the spring upper portion 14 and the air piston cylinder 32 (and the damper housing 36) connected to the spring lower portion 12. The distance between the spring upper part 14 and the spring lower part 12 is expanded and contracted by relative movement in the axial direction of the directional force generating device 4 and in the vertical direction. The movement limit on the bounce side of the air piston cylinder 32 with respect to the housing 28 is defined by the upper surface 40a of the air piston cylinder 32 coming into contact with the stopper 40b provided on the housing 28. The movement limit on the rebound side is determined by the air piston cylinder 32. The stopper 41 a provided on the housing 28 is defined by contacting the upper surface 41 b of the step portion of the housing 28.
The air chamber 38 is filled with compressed air as a fluid, and the vehicle body 14 is elastically supported by the compressed air. Further, by adjusting the amount of compressed air accommodated in the air chamber 38, the vehicle height (steady distance) that is the distance between the spring upper portion 14 and the spring lower portion 12 can be adjusted.

The vertical force generator 4 includes the housing 28, the screw shaft 42, the nut member 44, and the like.
The screw shaft 42 is supported by the housing 28 through a bearing 46 so as to be relatively rotatable, and is relatively rotated around the axis L _S. A rotation transmission device 8 is provided between the screw shaft 42 and the rotation shaft 50 of the electric motor 6, and rotation can be transmitted in both directions between them.
The screw shaft 42 is provided so as to penetrate the inner peripheral side of the nut member 44. Threaded portions are formed on the outer peripheral surface of the screw shaft 42 and the inner peripheral surface of the nut member 44, and are screwed together via bearing balls. The nut member 44 is fitted to the cylindrical member 58 so as not to be relatively rotatable and relatively unmovable, and the cylindrical member 58 is held by the housing 28 via the anti-rotation mechanism 60 so as not to be relatively rotatable and relatively movable in the axial direction. Yes. In the present embodiment, the screw shaft 42, the nut member 44, the anti-rotation mechanism 58, and the like constitute a motion conversion mechanism 62 that converts between rotational motion and linear motion. The cylindrical member 58 is fixed to the transmission member 66 of the vertical force transmission device 64.

The vertical force transmission device 64 includes a transmission member 66, compression coil springs 74 and 76, and the like, and is provided on the inner peripheral side of the air cylinder cylinder 32.
The transmission member 66 is held on the inner peripheral side of the air piston cylinder 32 so as to be relatively movable in the axial direction. The transmission member 66 generally has a disk shape, and a cylindrical member 58 of the nut member 44 is fixed to a central portion, and a piston rod 78 of a piston of the hydraulic shock absorber 16 is fixed. The outer peripheral portion is an intermediate retainer (also referred to as a common retainer) 79, and is positioned between the lower retainer 80 and the upper retainer 82. A compression coil spring 74 is provided between the upper retainer 82 and the intermediate retainer 79, and a compression coil spring 76 is provided between the intermediate retainer 79 and the lower retainer 80. The lower retainer 80 and the upper retainer 82 are fixedly provided on the air cylinder cylinder 32.

  Since the hydraulic shock absorber 16 is well known, a description thereof will be omitted. However, the hydraulic shock absorber 16 includes a piston that is slidably fitted to the inner peripheral side of the damper housing 36, and the piston relative to the damper housing 36. A damping force is generated with the movement. For example, since the nut member 44 is coupled to the piston rod 78 of the piston, a damping force is generated as the nut member 44 moves in the vertical direction.

The rotation transmission device 8 is a variable transmission ratio type rotation transmission device, and has a continuously variable transmission mechanism in this embodiment. The rotation transmission device 8 includes a variable pulley 90 provided on the screw shaft 42 of the vertical force generator 4, a variable pulley 92 provided on the rotation shaft 50 of the electric motor 6, and a belt stretched between them. 94. In this embodiment, the suspension side rotation shaft and the screw shaft 42 are integrally provided, and the motor side rotation shaft and the rotation shaft 50 of the electric motor 6 are integrally provided.
The variable pulley 90 includes a fixed rotator 100 formed on the screw shaft 42, a movable rotator 102 provided so as to be relatively movable with respect to the screw shaft 42, and a hydraulic cylinder 104 that moves the movable rotator 102. Including. The hydraulic cylinder 104 includes a housing 106 fixed to the screw shaft 42 and a piston member 108 provided in the housing 106 so as to be liquid-tight and slidable. The movable rotating body 102 cannot move relative to the piston member 108. It is attached. The screw shaft 42 is formed with a liquid passage 110 extending in the axial direction (the direction of the axis L _S ) and communicated with the liquid chamber 112. When the hydraulic fluid is supplied to the liquid chamber 112, the piston member 108 and the movable rotating body 102 approach the fixed rotating body 100, and the width of the V-shaped groove 114 formed between the fixed rotating body 100 and the movable rotating body 102 is reduced. It is made smaller. When the hydraulic fluid flows out from the liquid chamber 112, the piston member 108 and the movable rotating body 102 are separated from the fixed rotating body 100, and the width of the V-shaped groove 114 is increased.
Similarly, the variable pulley 102 provided on the rotating shaft 50 of the electric motor 6 includes a fixed rotating body 120, a movable rotating body 122, a hydraulic cylinder 124, and the like. In the hydraulic cylinder 124, a piston member 128 is fitted in a fluid-tight and slidable manner on a housing 126 fixed to the rotating shaft 50, and the movable rotating body 122 is held on the piston member 128. The movable rotating body 122 is moved closer to and away from the fixed rotating body 120 by the inflow / outflow of hydraulic fluid in the liquid chamber 130, and the width of the V-shaped groove 132 between the fixed rotating body 120 and the movable rotating body 122 is reduced. Or enlarged. A spring 134 is provided between the movable rotating body 122 and the housing 126. Incidentally, the rotary shaft 50, a fluid passage 135 extending in the axial L _M direction is provided, it is communicated with the liquid chamber 130.
In the present embodiment, the engagement diameter of the belt 94 is adjusted in the variable pulley 90, and the tension of the belt 94 is adjusted in the variable pulley 92. In the variable pulley 90, when the width of the V-shaped groove 122 is reduced and the engagement diameter is increased, in the variable pulley 92, the width of the V-shaped groove 132 is increased and the engagement diameter is decreased.

A fluid pressure circuit 140 is connected to the fluid chambers 112 and 130. The hydraulic circuit 140 includes a pump 144 that pumps and discharges the hydraulic fluid in the reservoir 142, a pump motor 145 that drives the pump 144, a discharge side of the pump 144, the reservoir 142, and each of the liquid chambers 112 and 130. There are provided valve devices 146 and 148, respectively. The valve devices 146 and 148 can control the pressure of the hydraulic fluid supplied to the liquid chambers 112 and 130, respectively, according to an electrical signal, and can be, for example, pressure control valves.
The valve devices 146 and 148 can also control the inflow and outflow flow rates of the hydraulic fluid in the liquid chambers 112 and 130. In this case, both the pressure control valve and the flow rate control valve are used. It will be included.

As shown in FIG. 2, the electric motor 6 is a three-phase brushless DC motor in which three-phase coils 150, 152, and 154 are star-connected (Y-connected), and is controlled by control of an inverter 156. The inverter 156 is a general one as shown in the figure, and the U-phase, V-phase, and W-phase coils 150, 152, and 154 of the electric motor 6 are on the high side (high potential side) and low side (low potential side). ) And six switching elements HUS, HVS, HWS, LUS, LVS, and LWS, respectively, and a switching element control circuit 160 that controls opening and closing of these switching elements. These six switching elements HUS, HVS, HWS, LUS, LVS, and LWS are connected to power storage device 164 via converter 162. The switching element control circuit 160 opens and closes the switching element based on the motor rotation angle (electrical angle), and controls the PWM (Pulse Width Modulation) of the plurality of switching elements to thereby control the amount of current flowing through the electric motor 6. Control. When the switching element control circuit 160 changes the duty ratio R _duty (= T _ON / (T _ON + T _OFF )) determined by the pulse on time T _ON and the pulse _off time T _OFF , the amount of current flowing through the electric motor 6 is controlled. The magnitude of the rotational torque is controlled. Specifically, when the duty ratio is increased, the amount of current is increased and the rotational torque generated in the electric motor 6 is increased.
The electromotive force generated by the function of the electric motor 6 as a generator can be regenerated in the power storage device 164, thereby suppressing the relative movement of the electromagnetic suspension 10.

FIG. 6 shows TN characteristics (torque / rotational speed characteristics) of the electric motor 6 in this embodiment. As shown in the figure, at the time of power running, the rotational speed N _M is capable of outputting torque is reduced significantly, during regenerative operation, it can be outputted torque and rotational speed N _M is reduced is reduced. Further, as shown in the figure, regarding the TN characteristics of the electric motor 6 in the present embodiment, the relationship between the rotational speed and the outputtable torque is a relationship represented by a straight line. Even if the electric motor 6 having this characteristic rotates at a speed higher than the upper limit rotational speed N _MAX , no driving torque is generated. For this reason, during powering operation, it is usually used within a range not _exceeding the upper limit rotational speed N _MAX . In the state in which the electric motor 6 is rotating at a speed higher than the upper limit rotation speed N _MAX , the electric motor 6 operates as a generator, so that the speed of changing the distance between the spring upper portion 14 and the spring lower portion 12 of the expansion / contraction mechanism 20 ( Hereinafter, it is possible to apply a damping force according to the expansion / contraction speed of the expansion / contraction mechanism 20 or abbreviated as the vertical stroke speed).

As shown in FIG. 3, the suspension control ECU 170 is configured mainly by a computer including an execution unit, an input / output unit, a storage unit, and the like. The input / output unit includes a vehicle height sensor 172 and a power storage device 164. Are connected to a storage amount sensor 174 for detecting the stored amount of electricity, a detection device 175 for controlling the vertical force, and the solenoids of the switching element control circuit 160, the pump motor 145 of the hydraulic circuit 140, and the valve devices 146 and 148. Etc. are connected via a drive circuit (not shown). The switching element control circuit 160 is connected to a rotation angle sensor (for example, a resolver) 176 that detects the rotation angle of the electric motor 6.
The vehicle height sensor 172 is provided for each of the front, rear, left and right wheels, and detects a vehicle height that is a relative position of each spring upper portion 14 to the spring lower portion 12. If the detected value is differentiated with respect to time, the vehicle height changing speed, that is, the vertical stroke speed can be obtained.
The power storage amount sensor 174 detects the amount of power (power storage amount) actually stored in the power storage device 164. Based on the amount of stored electricity, the amount of power (charge amount) that can be charged (supplied) to the power storage device 164 can be acquired. Normally, the power storage device 164 is maintained such that electric power of a predetermined amount or more is stored. Therefore, when the actual power storage is less than the set amount, the amount of power storage is insufficient, and it can be assumed that the battery should be charged quickly.
The vertical force control detection device 175 includes, for example, the above-described vehicle height sensor, a sprung acceleration sensor that detects the vertical acceleration of the spring upper portion 18, and a lateral acceleration of the vehicle. A lateral acceleration sensor, a longitudinal acceleration sensor that detects longitudinal acceleration, and the like are included. The vertical force is controlled based on the detection value of one or more of these sensors.
The storage unit stores a plurality of programs, data, and the like such as the electric motor control program represented by the flowchart of FIG. 4 and the transmission ratio control program represented by the flowchart of FIG.

In the electromagnetic suspension configured as described above, when the electric motor 6 is driven by power supplied from the power storage device 164, the rotation of the rotating shaft 50 is transmitted to the screw shaft 42 via the rotation transmitting device 8. Then, the screw shaft 42 is rotated. The driving torque of the electric motor 6 is transmitted to the screw shaft 42 and applied as a vertical force to the cylindrical member 58 via the nut member 44. The vertical force applied to the cylindrical member 58 is applied to the cylinder cylinder 32 via the vertical force transmission device 64 or applied to the piston of the hydraulic shock absorber 16. This force acts as an approach / separation force (vertical force) between the spring top 14 and the spring bottom 12.
In the present embodiment, control that combines vibration suppression control, roll suppression control, and pitch suppression control is executed. For each of the front, rear, left, and right wheels, the target vertical force is determined in each of the vibration suppression control, roll suppression control, and pitch suppression control, and the total of the target vertical force determined in each is output. A current supplied to the motor 6 (inverter 156) is controlled.

In the vibration suppression control, the target vertical force (vibration suppression target value) is determined to have a direction and magnitude that can suppress the vibration of the sprung portion 14. The absolute sprung speed is acquired based on the value detected by the sprung acceleration sensor, and a value obtained by multiplying the sprung absolute speed by a predetermined gain (attenuation coefficient) is set as the vibration suppression target value. The direction of the vibration suppression target value is opposite to the direction of the stroke of the sprung portion 14. Even if the vibration suppression control is performed when a start condition such as when the magnitude of the sprung absolute speed is greater than or equal to a predetermined set value is satisfied, It may be performed.
In the roll suppression control, the target vertical force (the target value for roll suppression) is determined to have a direction and magnitude that can suppress the roll moment generated when the vehicle turns. The direction of the roll suppression target value is the direction in which the sprung portion 14 and the unsprung portion 12 approach each other on the turning inner ring side, and the separating direction on the turning outer ring side. The magnitude is a magnitude obtained by multiplying the absolute value of the lateral acceleration acting on the vehicle by a gain. Note that the roll suppression control is executed when the absolute value of the lateral acceleration is equal to or greater than a predetermined set value.
In the pitch suppression control, the target vertical force (target value for pitch suppression) is determined to have a direction and magnitude that can suppress the pitch moment generated during braking and braking of the vehicle body. For example, at the time of driving, the direction of the target value for pitch suppression is a direction in which the spring upper portion 14 and the spring lower portion 12 approach each other on the front wheel side, and a direction in which they are separated on the rear wheel side. The magnitude is a magnitude obtained by multiplying the absolute value of the longitudinal acceleration acting on the vehicle by a gain. Note that the pitch suppression control is executed when the absolute value of the longitudinal acceleration is greater than or equal to a predetermined set value.
The target vertical force in each of the front, rear, left and right electromagnetic suspensions is the sum of the vibration suppression target value, the roll suppression target value, and the pitch suppression target value.

  Further, when a vertical force is applied to the vertical force generator 4 by road surface input or the like, torque is applied to the screw shaft 42 via the cylindrical member 58 and the nut member 44. When the screw shaft 42 is rotated, the rotation is transmitted to the electric motor 6 via the rotation transmission device 8. The rotating shaft 50 of the electric motor 6 is rotated and functions as a generator (when the electric motor 6 is not in a free state). In the electric motor 6, an electromotive force corresponding to the number of rotations of the electric motor 6 is generated by electromagnetic induction and is applied to the screw shaft 42 via the rotation transmission device 8. The resistance force applied to the screw shaft 42 is a force corresponding to the rotation speed of the electric motor 6, that is, the vertical stroke speed, and acts as a damping force. Further, when the electromotive force is stored in the power storage device 164 when functioning as a generator, a resistance force is applied thereby.

In this embodiment, the speed ratio ε in the rotation transmission device 8 is controlled based on the vertical stroke speed, the operating state of the electric motor 6 and the like as shown in FIGS. By the motion conversion mechanism 60, the rotational speed of the screw shaft 42 and the absolute value of the vertical stroke speed (the absolute value of the differential value with respect to the time of the detected value by the vehicle height sensor 172) correspond one-to-one.
The speed ratio ε can be expressed as the following equation.
ε = R _M / R _S = ω _S / ω _M = T _M / T _S
In the above equation, R _M and R _S are the engagement diameters of the belt 94 on the electric motor side (variable pulley 92) and the telescopic mechanism (suspension) side (variable pulley 90), respectively, and ω _M and T _M are respectively Represents the rotational angular velocity and rotational torque of the electric motor 6, and ω _S and T _S represent the rotational angular velocity and rotational torque of the screw shaft 42 of the vertical force generator 4.
From the above equation, in the rotation transmission device 8, there is a relational expression ε _ro · ε _tq = 1 between the speed ratio ε _ro (ω _S / ω _M ) and the torque ratio ε _tq (T _S / T _M ).
It can be seen that In the rotation transmission device 8 in the present embodiment, when the gear ratio changes, the torque ratio also changes accordingly.

As shown in FIG. 7A, the gear ratio ε is set to a reference value ε ₀ (for example, 1) in the normal operation state. The normal operating state is a normal traveling state of the vehicle, and is a state where the absolute value of the vertical stroke speed is equal to or less than the set value _Vth . Setting value V _th, when the speed ratio epsilon is the reference value epsilon _0, a rate at which the rotational speed N _M of the electric motor 6 is the upper limit rotation speed N _MAX (see FIG. 6).
ε ₀ = R _M0 / R _S0 = ω _S0 / ω _M0 = T _M0 / T _S0
However, in the state the gear ratio is the reference value epsilon _0, the upper and lower absolute value of the stroke speed is greater than the set value V _th, when the rotational speed N _M of the electric motor 6 is greater than the upper limit rotation speed N _MAX is drawing As shown in FIG. 7B, the speed ratio ε of the rotation transmission device 8 is increased to ε _H. In the rotation transmission device 8, the engagement diameter R _S of the belt 94 in the variable pulley 90 is decreased, and the engagement diameter R _M of the belt 94 in the variable pulley 92 is increased to adjust the tension (ε _H = R _MH / R). _SH ).
As a result, even if the absolute value of the vertical stroke speed is large, the rotational speed of the electric motor 6 can be reduced, for example, the rotational speed _NHH shown in FIG. In this case, the vertical force generator 4 includes
T _SH = T _MH / ε _H
A torque T _SH having a magnitude represented by

On the other hand, the case where the storage amount Q of the power storage device 164 is smaller than the set value Q _th and the case where the decreasing gradient (−dQ / dt) of the storage amount Q is greater than or equal to a predetermined set gradient (ΔQ _th ). In at least one of the cases, it is assumed that the power storage device 164 needs to be charged quickly, and the regenerative operation is performed. In that case, as shown in FIG. 7 (c), the speed ratio ε is reduced to ε _L. In the rotation transmission device 8, the engagement diameter R _S of the belt 94 in the variable pulley 90 is increased, and the engagement diameter R _M of the belt 94 in the variable pulley 92 is decreased to adjust the tension (ε _L = R _ML / R). _SL ). The rotation speed N _M of the electric motor 6 is increased with respect to the rotation speed N _S of the screw shaft 42.
In regenerative operation, a larger electromotive force is obtained when the rotational speed of the electric motor 6 is larger. Therefore, the rotational speed N _M of the electric motor 6 is usually regenerative operation is not performed when the regenerative corresponding set speed N _thr smaller (N _M <N _thr) shown in FIG. In contrast, in the present embodiment, even with a small absolute value of the vertical stroke speed for speed ratio ε is reduced during regenerative operation, it is possible to increase the rotational speed N _M of the electric motor 6, conventionally, the row Regeneration operation can be performed even if it is not missed. Further, since the number of revolutions of the electric motor 6 can be increased even in a region where the regenerative operation is performed conventionally, the generated electromotive force is increased accordingly, and the power storage device 164 can be effectively powered. Can be charged. In this case, the regenerative braking torque generated by the regenerative operation is transmitted to the vertical force generator 4 via the rotation transmission device 8. Thereby, expansion and contraction of the electromagnetic suspension can be suppressed.
In the case where the electromagnetic suspension in this embodiment is provided in a hybrid vehicle or an electric vehicle, when the power storage device 164 is common with the driving electric motor, the driving electric motor is operated. (When power is supplied from the power storage device 164 to the driving electric motor), the regenerative operation can be performed. This case corresponds to a case where the decrease gradient of the charged amount is equal to or greater than the set gradient.

The electric motor control program of FIG. 4 is executed at predetermined time intervals while the vehicle is traveling.
In step 1 (hereinafter abbreviated as S1. The same applies to other steps), the amount of power storage is detected, and it is determined whether or not there is a charge request. As described above, the charge request is generated in at least one of the case where the charged amount Q is smaller than the set amount Q _th and the decrease gradient (−dQ / dt) of the charged amount Q is equal to or greater than the set gradient (ΔQ _th ). It is determined that there is. If there is no charge request, it is determined in S2 whether or not there is a request for control of the vertical force. As described above, when the control of the vertical force is executed when a predetermined start condition is satisfied, it is determined that there is a control request when the start condition is satisfied. If the vertical force control is always performed while the vehicle is running, the determination in S2 is always YES.
If there is a request for control of the vertical force, in S3, control of the current supplied to the electric motor 6 (control of the inverter 156) is performed for the wheel so that the target vertical force is obtained. On the other hand, when there is a charge request, regenerative operation is performed in S4. Inverter 156 is controlled such that the electromotive force generated in electric motor 6 is supplied to power storage device 164. In this case, the above-described vertical force control is not performed.

The transmission ratio control program represented by the flowchart of FIG. 5 is executed at predetermined time intervals while the vehicle is running.
In S11, it is determined whether or not there is a charge request, as in the case described above. If there is no charge request, the vertical stroke speed is acquired based on the differential value (dH / dt) of the detected value H by the vehicle height sensor 172 in S12, and the absolute value of the vertical stroke speed is set to the set value V in S13. _It is determined whether it is greater than _th . If it is equal to or less than the set value V _th , the speed ratio ε is set to 1 (reference value) in the rotation transmission device 8 in S14. If it is greater than the set value V _th , the speed ratio ε is set to 1 in S15. The value ε _H is larger than the (reference value).
On the other hand, if there is a charge request, the gear ratio ε is set to a value ε _L smaller than 1 (reference value) in S16.

As described above, in the present embodiment, as shown by the solid line of FIG. 8 (a), when the absolute value of the upper and lower stroke speed is greater than the set value V _th has gear ratio ε than the set value or less V _th Increased. As a result, as shown by the solid line in FIG. 8 (b), the rotational speed N _M of the electric motor 6 can be prevented from becoming excessively large, even larger absolute value of the upper and lower stroke speed, the appropriate torque Can be added.
Further, since the rotational speed N _M of the electric motor 6 is prevented from becoming excessively large, the electric motor 6, it is out of those of the upper limit rotation speed N _MAX is small characteristics. As a result, the cost of the electric motor 6 can be reduced.
Further, the switching speed of the switch of the inverter 156 for controlling the electric motor 6 can be made slow, and the switching element control circuit 160 can be made slow in the calculation speed. As a result, the cost of the inverter 156 and the switching element control circuit 160 can be reduced. In addition, since the number of times the inverter 156 is switched can be reduced, there is an advantage that the life can be extended accordingly.
Further, during regenerative operation, it is possible to increase the rotational speed N _M of the electric motor 6 with respect to the absolute value of the vertical stroke speed, it is possible to generate a large electromotive force, effective electrical energy storage device 164 Can be charged.
In the present embodiment, the screw shaft 42 corresponds to a rotating member, and the nut member 44 corresponds to a non-rotating member.
Further, a part for storing S12, 13, 15 of the transmission ratio control program of FIG. 5 of the suspension ECU 170, a part for executing the high-speed movement speed ratio control part is configured, a part for storing S11, 16 and a part for executing it. Thus, a regenerative operation speed ratio control unit is configured. The high speed movement gear ratio control unit is also a gear ratio increasing unit.
Further, a portion for storing S14-16 of the gear ratio control program of FIG. 5 of the suspension ECU 170, a portion for executing, the variable pulleys 90 and 92, the hydraulic circuit 140, and the like constitute a groove width changing portion.

The set value V _th of the absolute value of the vertical stroke speed described above can be set to a value smaller than the speed corresponding to the upper limit rotation speed N _MAX of the electric motor 6. Thereby, it is possible to satisfactorily avoid that the rotation speed of the electric motor 6 exceeds the upper limit rotation speed _NMAX .
Further, the control of the speed ratio ε is not limited to that in the above embodiment. For example, the speed ratio ε can be set to a value that increases as the absolute value of the vertical stroke speed increases as indicated by the alternate long and short dash line in FIG. By doing so, for example, it is possible to maintain the rotational speed N _M of the electric motor 6 constant. In this case, it is desirable that the relationship between the speed ratio ε and the absolute value of the up / down stroke speed is tabulated and stored in the storage unit in advance. Further, the gear ratio ε can be controlled to be larger when the absolute value of the vertical stroke speed is large than when it is small. Thereby, the rotational speed of the electric motor 6 can be relatively reduced. Furthermore, the speed ratio ε can be controlled so that the number of rotations of the electric motor 6 becomes a desired magnitude.
Furthermore, when the charge request level in the power storage device 164 is acquired based on at least one of the power storage amount actually stored in the power storage device 164 and the decreasing gradient of the power storage amount, and the charge request level is strong The gear ratio ε can be made smaller than when it is weak. For example, the gear ratio ε can be made smaller when the storage amount is small than when it is large, and the gear ratio ε can be made smaller than when it is small when the decrease gradient is large. Thereby, the number of rotations of the electric motor 6 can be made larger than the number of rotations of the screw shaft 42 than when the charging request is strong and weak.
In the above embodiment, the screw shaft 42 is a rotating member and the nut member 44 is a non-rotating member. However, the nut member 44 is a rotating member and the screw shaft 42 is a non-rotating member. It can also be applied to suspensions.
Further, in the above embodiment, the electric motor 6 has a characteristic in which the relationship between the torque and the rotational speed is represented by a straight line, but has a characteristic in which the relationship between the torque and the rotational speed is represented by a curve. It can also be applied to things.
Further, the electric motor 6 can be an electric motor with a speed reducer, or a transmission can be provided between the motor shaft 50 and the motor side rotating shaft. Furthermore, a transmission between the screw shaft 42 and the suspension side rotation shaft can be provided in the telescopic mechanism 20. Further, the manner of controlling the vertical force is not limited to that in the above embodiment.

Furthermore, in the above-described embodiment, the rotation transmission device has a continuously variable transmission mechanism including a variable pulley, but may have a planetary gear mechanism. An example in that case is shown in FIG.
In this embodiment, the vertical force generator 200 is provided between the spring upper part 14 and the spring lower part 12 in parallel with a coil spring 202 as a suspension spring. The vertical force generating device 200 includes an inner cylinder 204 provided on the spring upper portion 14 so as to be relatively non-movable in the vertical direction, and an outer cylinder 206 provided on the spring lower portion 12 so as to be relatively non-movable in the vertical direction. A pair of screw shafts 208 and a nut member 210 are included. The screw shaft 208 is held by the inner cylinder 204 through a bearing 212 so as to be relatively rotatable, and an output shaft 224 of the main electric motor 220 is connected through a rotation transmission device 226. The screw shaft 208 is provided through the nut member 210 and is screwed together via a ball provided between the outer peripheral surface of the screw shaft 208 and the screw portion provided on the inner peripheral surface of the nut member 210. .
The nut member 210 is fixed to the cylindrical transmission member 230, and the transmission member 230 is fixed to the outer cylinder 206. In addition, the inner cylinder 204 is held relative to the outer cylinder 206 via a detent mechanism 232 so that the inner cylinder 204 is not relatively rotatable and is relatively movable in the axial direction. Thereby, the relative rotation of the nut member 210 is prevented. The screw shaft 208, the nut member 210, the anti-rotation mechanism 232, and the like constitute a motion conversion mechanism 234.
The suspension spring 202 is provided between an upper retainer 240 fixed to the spring upper portion 14 (inner cylinder 204) and a lower retainer 242 fixed to the outer cylinder 206.

The rotation transmission device 226 is a variable gear ratio type device and has a planetary gear mechanism. The rotation transmission device 226 includes a sun gear 250, a ring gear 252, three planetary gears 254, a suspension side gear 256, and the like. The suspension side gear 256 is provided in a state of being meshed with the outer peripheral surface of the ring gear 254.
The sun gear 250 is attached to the rotation shaft 224 of the main electric motor 220 so as not to be relatively rotatable, and the suspension-side gear 256 is attached to the screw shaft 208 so as not to be relatively rotatable. In the present embodiment, rotation is transmitted between the sun gear 250 and the ring gear 252 (suspension side gear 256).
The three planetary gears 254 mesh with the outer peripheral portion of the sun gear 250 and are engaged with the inner peripheral portion of the ring gear 252, and a pair of connecting members (planetary gear carriers) 258, 259 provided on both sides in the axial direction. Are connected to each other so as to be relatively rotatable. An output shaft of the auxiliary electric motor 260 is fixed to the connecting member 258. Hereinafter, the connecting members 258 and 259 may be combined, or one of the connecting members 258 and 259 may be referred to as a planetary gear carrier.
In this embodiment, the vertical force applied to the electromagnetic suspension 200 is controlled by the control of the main electric motor 220, and the speed ratio ε in the rotation transmission device 226 is changed by the control of the sub electric motor 260.

In this embodiment, the gear ratio γ between the ring gear 252 and the suspension side gear 256 is expressed by the equation γ = −Z _R ′ / Z _S = ω _S / ω _R = T _R / T _S
It is represented by Here, ω _S , Z _S , T _S are the rotational angular velocity, the number of teeth, and the torque of the suspension side gear 256, and ω _R , Z _R ′, T _R are the rotational angular velocity, the number of teeth (outside) of the ring gear 252, Torque.
Further, in the planetary gear mechanism, in a state where the rotation of the planetary gear carrier 258 is blocked, the transmission ratio ε _P between the ring gear 252 and the sun gear 250 (on the electric motor side) is expressed by the equation ε _P = −Z _M / Z _R = ω _R / ω _M = T _M / T _R
Represented by Here, ω _M , Z _M , and T _M are the rotational angular velocity, the number of teeth, and the torque of the sun gear 250, and Z _R is the number of teeth inside the ring gear 252.
From these relationships, the rotational angular speed of the sun gear 250 (the rotational angular speed ω of the main electric motor 220) at the transmission ratio ε {the rotational angular speed of the suspension side gear 256 (the rotational angular speed ω _S of the screw shaft 208 of the electromagnetic suspension 200) in the rotation transmission device 226. _M )) (ω _S / ω _M )} is given by the equation ε = ε _P · γ
Can be expressed as From this equation, when the gear ratio γ is 1, the transmission gear ratio ε _P in the planetary gear mechanism and the transmission gear ratio ε of the rotation transmission device 226 are the same, but even if the gear ratio γ is not 1, it is fixed. Therefore, the transmission gear ratio ε _P in the planetary gear mechanism and the transmission gear ratio ε of the rotation transmission device 226 have a one-to-one correspondence.
The rotational angular velocity and torque are values having a magnitude and a direction. When the directions are opposite, the signs (+,-) are reversed. In this embodiment, the gear ratio γ and the speed ratio ε _P in the planetary gear mechanism are negative values. The rotation direction of the ring gear 252 and the rotation direction of the suspension side gear 256 are opposite, and the rotation direction of the ring gear 252 and the rotation direction of the sun gear 250 are opposite.
Hereinafter, in order to simplify the description, the gear ratio ε _P in the planetary gear mechanism will be described.

As shown in FIG. 10A, when the revolution of the planetary gear 254 is blocked by the auxiliary electric motor 260 (when the rotation of the planetary carrier 258 is blocked, the rotation of the auxiliary electric motor 260 is blocked. The planetary gear 254 is rotated at that position.
As described above, the transmission ratio ε _P0 in the planetary gear mechanism is expressed by the equation ε _P0 = −Z _M / Z _R = ω _R0 / ω _M0 = T _M / T _R
The value represented by
As shown in FIGS. 10B and 10C, when the planetary gear 254 is revolved with respect to the sun gear 250 (when the planetary carrier 258 is rotated and the auxiliary electric motor 260 is rotated). The planetary gear 254 revolves while rotating. Rotational angular velocity omega _R of the ring gear 252 in this case, when the omega _C (rotational angular speed of the planetary carrier) revolution speed of the planetary gear 254, wherein _{ω R = - (Z M /} Z R) · (ω M -ω C ) + Ω _C = ε _P0 (ω _M −ω _C ) + ω _C
It is known that Further, from this equation, the gear ratio ε _P when the revolution speed of the planetary gear 254 is not 0 is expressed by the equation ε _P = ω _R / ω _M = ε _P0 −ε _P0 {ω _C / ω _M −ω _C / (ω _M・ Ε _P0 )}
It becomes.
As shown in FIG. 10B, when the planetary gear 254 is revolved in the direction opposite to that of the sun gear 250, the sign is reversed between the rotational angular velocity ω _M and the rotational angular velocity ω _C. As a result, the rotational angular velocity omega _R of the ring gear 252, when the magnitude of the rotational angular velocity omega _M of the sun gear 250 are the same, becomes larger than the state of revolution of the planetary gear 254 is prevented, the gear ratio ε _P (ω _R / ω _M The absolute value of) becomes larger than the case where the revolution is prevented and becomes ε _PH . When the revolution speed ω _{C in} the reverse direction of the planetary gear 254 is large, the rotational angular speed ω _{R of the} ring gear 252 is larger than when it is small, and the absolute value of the gear ratio ε _PH is also larger.
| Ε _PH | = | ω _RH / ω _M |> | ε _P0 |
As shown in FIG. 10C, when the planetary gear 254 is revolved in the same direction as the sun gear 250, the rotational angular velocity ω _M and the rotational angular velocity ω _C have the same sign. The absolute value of the speed ratio ε _P becomes smaller than the case where revolution is prevented and becomes ε _PL . The rotational angular velocity ω _R of the ring gear 252 is smaller than the state in which the revolution of the planetary gear 254 is prevented.
| Ε _PL | = | ω _RL / ω _M | <| ε _P0 |
In this case, the rotational angular speed ω _RL of the ring gear 254 is smaller when the revolution speed ω _C is large (when it is close to a free state) than when it is small.

As shown in FIG. 11, the suspension ECU 280 mainly includes a computer, and includes an input / output unit, an execution unit, a storage unit, and the like. The input / output unit includes a vehicle height sensor 172, a storage amount sensor 174, upper and lower parts. A direction force control detecting device 175 is connected, and two switching element control circuits 284 and 286 are connected. The switching element control circuit 284 is a computer that controls the inverter 290 provided corresponding to the main electric motor 220, and the switching element control circuit 286 is a computer that controls the inverter 292 provided corresponding to the auxiliary electric motor 260. It is.
The main electric motor 220 and the sub electric motor 260 are brushless DC motors as in the above embodiment, and the structures of the inverters 290 and 292 are the same as in the above embodiment. The power storage device 164 is common to the electric motors 220 and 260. The switching element control circuits 284 and 286 are connected to rotation angle sensors 294 and 296 for detecting the rotation angles of the main electric motor 220 and the sub electric motor 260, respectively.

In the present embodiment, the main electric motor 220 is controlled according to the electric motor control program represented by the flowchart of FIG. 4, and the auxiliary electric motor 260 is controlled according to the speed ratio control program represented by the flowchart of FIG. Therefore, the main electric motor can be referred to as a vertical force control motor, and the auxiliary electric motor 260 can be referred to as a speed control motor or a gear ratio control motor.
Steps in which the same execution is performed in the transmission ratio control program represented by the flowchart of FIG. 12 and the transmission ratio control program represented by the flowchart of FIG.
In S20, it is determined whether or not the main electric motor 220 is in operation. The main electric motor 220 may be in a power running operation or a regenerative operation.
If the main electric motor 220 is in operation, it is determined in S11 whether or not there is a charge request for the power storage device 164. If there is no charge request, the absolute value of the vertical stroke speed is determined in S12 and S13. Is greater than the set value _Vth . If it is equal to or less than the set value V _th , the revolution of the planetary gear 254 is prevented by the control of the sub electric motor 260 in S14 ′, and if it is greater than the set value V _th , the sub electric motor 260 is controlled in S15 ′. Under the control, planetary gear 256 is revolved in the reverse direction to sun gear 250 at a predetermined set speed. Thereby, it is possible to reduce the rotational speed N _M of the main electric motor 220 relative to the rotational speed N _S of the screw shaft 208. If it is determined that there is a charge request and the regenerative operation is performed, the planetary gear 254 is revolved at the predetermined speed in the same direction as the sun gear 250 under the control of the auxiliary electric motor 260 in S16 ′. It is done. Thereby, it is possible to increase the rotational speed N _M of the main electric motor 220 relative to the rotational speed N _S of the screw shaft 208.
In the present embodiment, the planetary gear carrier rotation control unit is configured by the part for storing S14 ', 15', 16 ', the part for executing, etc. of the suspension ECU 280.

  In the above embodiment, the revolution speed is a fixed value, but the magnitude of the revolution speed can be determined each time. For example, if the revolution speed of the planetary gear 254 in the direction opposite to the sun gear 250 is increased, the rotational speed of the main electric motor 220 with respect to the absolute value of the vertical stroke speed can be reduced. The revolving speed in the reverse direction of the planetary gear 254 can be increased as compared with the case where it is small. Further, if the revolution speed of planetary gear 254 in the same direction as sun gear 250 is increased, the rotational speed of main electric motor 220 relative to the rotational speed of screw shaft 42 can be increased. For example, when the charge request is strong, the revolution speed in the same direction can be made larger than when the charge request is weak. When the amount of stored electricity is small, the rotational speed is increased as compared to when it is large, and when the decrease gradient is large, the rotational speed is increased as compared with the case where it is small. In these cases, the relationship between the rotational speed of the planetary gear carrier 258 and the absolute value of the vertical stroke speed, and the relationship between the rotational speed and the degree of charge request can be stored in a table in advance.

In the above embodiment, the rotation state of the planetary gear 254 is controlled by the auxiliary electric motor 260. However, it can be controlled by a brake. An example of that case is shown in FIG. In this embodiment, the auxiliary electric motor 260 is not necessary.
In FIG. 13, the planetary gear 254 is connected to each other by a pair of connecting members (planetary gear carriers) 300 and 302 so as to be relatively rotatable. In this embodiment, a shaft 304 for holding the planetary gear 254 is relatively rotatable. The connection members 300 and 302 are provided so as not to protrude from the end faces.
In addition, brakes 312 and 314 are provided on the housing 310 that holds the planetary gear mechanism, the electric motors 220 and 260, etc., corresponding to the connection members 300 and 302, respectively. The brakes 312 and 314 have the same structure and include a friction member 320 and a brake cylinder 322, respectively. When hydraulic fluid is supplied to the hydraulic chamber 324 of the brake cylinder 322, the piston 326 is advanced, the friction member 320 is frictionally engaged with the connection members 300 and 302, respectively, and the rotation of the connection members 300 and 302 is suppressed. Is done. When the hydraulic fluid flows out from the hydraulic chamber 324, the piston 326 is retracted, and the rotation of the connecting members 300 and 302 is allowed.

A hydraulic circuit 340 is connected to the hydraulic chamber 324. The hydraulic circuit 340 includes a pump 344 that pumps up and pressurizes the hydraulic fluid in the reservoir 342, a pump motor 346 that drives the pump 344, a supply control valve 348 provided between the discharge side of the pump 344 and the hydraulic chamber 324, A discharge control valve 350 provided between the hydraulic chamber 324 and the reservoir 342 is included, and the hydraulic pressure in the hydraulic chamber 324 is controlled by the control of the supply control valve 348 and the discharge control valve 350.
By controlling the fluid pressure in the fluid pressure chamber 324, the rotation of the connecting members 300 and 302, that is, the revolution state of the planetary gear 254 can be controlled (a state in which revolution is prevented, a state in which free revolution is allowed, a state in which revolution is allowed) State to add restrictions). In this embodiment, the hydraulic pressures in the hydraulic chambers 324 of the brakes 312 and 314 are controlled in common.
Thus, by controlling the hydraulic pressures of the brakes 312 and 314, the planetary gear 254 can be switched between a state in which the rotation of the planetary gear 254 in the same direction as the sun gear 250 and a state in which the restriction is applied, and the speed ratio ε _{P is set} to ε _P0. And 0 (ε _P0 <ε _P <0), and the rotational angular velocity ω _R of the ring gear 252 can be controlled between ε _P0 · ω _M <ω _R <0. It becomes.

The brakes 312 and 314 may be electric brakes that are driven by solenoids, electric motors, or the like.
Further, in the electromagnetic suspension of Figure 9 and 13, it may be provided coaxially with the rotation axis L _M of the electric motor 220 and the axis L _S of the vertical force generator 200.
In addition to the above-described embodiments, the present invention can be carried out in various modifications and improvements based on the knowledge of those skilled in the art.

It is sectional drawing which shows notionally the electromagnetic suspension which is one Example of this invention. It is a figure which shows the switching circuit which controls the said electric motor. It is a figure which shows the periphery of suspension ECU contained in the said electromagnetic suspension. It is a flowchart showing the electric motor control program memorize | stored in the memory | storage part of the said suspension ECU. It is a flowchart showing the gear ratio control program memorize | stored in the memory | storage part of the said suspension ECU. It is a figure which shows the TN characteristic of the said electric motor. It is a figure which shows notionally the state of the said rotation transmission apparatus. (a) It is a figure which shows the relationship between the absolute value of up-down stroke speed, and the gear ratio of a rotation transmission apparatus. (b) It is a figure which shows the relationship between the absolute value of an up-and-down stroke speed, and the rotation speed of an electric motor. It is sectional drawing which shows notionally the electromagnetic suspension which is another one Example of this invention. It is a figure which shows the state of the said rotation transmission apparatus. FIG. 3 is a diagram conceptually showing the periphery of a suspension ECU included in the electromagnetic suspension. It is a flowchart showing the gear ratio control program memorize | stored in the memory | storage part of the said suspension ECU. It is sectional drawing which shows notionally the electromagnetic suspension which is another one Example of this invention.

Explanation of symbols

  4, 200: Vertical force generator 6: Electric motor 8: Rotation transmission device 12: Spring lower portion 14: Spring upper portion 42: Screw shaft 44: Nut member 50: Rotating shaft 60: Motion conversion mechanism 64: Vertical force transmission device 90 , 92; variable pulley 94: belt 100, 120: fixed rotating body 102, 122: movable rotating body 104, 124: hydraulic cylinder 140: hydraulic circuit 146, 148: valve device 156, 290, 292: inverter 170, 280 : Suspension ECU 172: Vehicle height sensor 174: Storage amount sensor 160, 284, 286: Switching element control circuit 202: Suspension spring 208: Screw shaft 210: Nut member 220: Main electric motor 226: Rotation transmission device 260: Sub electric motor 250: Sun gear 252: Ring Gear 254: Planetary gear 256: Suspension side gear 258, 259: Planetary gear carrier (connection member) 312, 314: Brake 320: Friction member 322: Hydraulic cylinder 340: Hydraulic circuit

Claims (7)

(a) an electric motor, and (b) a rotating member provided between the sprung portion and the unsprung portion of the vehicle and capable of transmitting rotation to and from the electric motor via a rotation transmitting device, and (c) An electromagnetic suspension that includes a non-rotating member engaged with the rotating member in a state where conversion between a rotational motion and a linear motion is possible, and applies a vertical force between the spring upper portion and the spring lower portion. There,
The rotation transmission device is provided between a motor-side rotating shaft connected to the electric motor and a suspension-side rotating shaft connected to the rotating member, and the motor-side rotating shaft has a rotation angular velocity of the suspension-side rotating shaft. An electromagnetic suspension, characterized in that it is a variable transmission ratio type rotation transmission device in which the ratio to the rotational angular velocity is variable.   The electromagnetic suspension according to claim 1, wherein the electric motor is provided in a state in which a rotation axis thereof and a rotation axis of the rotation member do not exist on the same straight line.   When the absolute value of the expansion / contraction speed of the distance between the sprung portion and the unsprung portion is greater than a predetermined setting value, the speed ratio variable type rotation transmission device is less than the setting value than the ratio. The electromagnetic suspension according to claim 1, further comprising a high speed movement speed ratio control unit that increases   2. The transmission ratio variable type rotation transmission device includes a transmission ratio increasing unit that increases the ratio when the absolute value of the expansion / contraction speed of the distance between the sprung part and the unsprung part is small. The electromagnetic suspension as described in any one of thru | or 3.   5. The regenerative operation speed ratio control unit that makes the ratio smaller than when the electric motor is in a regenerative operation state and in a powering operation state when the electric motor is in a regenerative operation state. The electromagnetic suspension as described in any one.   The transmission ratio variable type rotation transmission device includes: (i) a variable pulley connected to the motor side rotation shaft and the suspension side rotation shaft, respectively, and a belt stretched between the pair of variable pulleys. 6. A continuously variable transmission mechanism, and (ii) a groove width changing portion that changes a width of the belt by changing a width of a V-shaped groove of the pair of variable pulleys. The described electromagnetic suspension.   The transmission ratio variable type rotation transmission device includes: (i) a sun gear connected to the motor side rotation shaft, a ring gear connected to the suspension side rotation shaft, and a planetary gear provided between the sun gear and the ring gear; And (ii) a planetary gear carrier rotation control unit that changes the ratio between the rotation angular velocity of the sun gear and the rotation angular velocity of the ring gear by controlling the rotation state of the planetary gear carrier that holds the planetary gear. The electromagnetic suspension according to any one of claims 1 to 5.

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