JP2007290669A - Electromagnetic suspension system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic suspension system which charges an electric source effectively and generates the sufficient load even when the stroke speed is in the middle and high speed range. <P>SOLUTION: The electromagnetic suspension system comprising: one side member 1 and the other side member 2 to show relative movement for one side member 1; and a motor M sustaining at least the relative movement 1, is provided with variable resistors r1, r2, r3 connected to a winding 12 of the motor M, so as to adjust the resistance of the variable resistors r1, r2, r3, and to control the short-circuit characteristics T which is the relationship of the stroke speed with the load in which the motor M is short-circuited. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an improvement of an electromagnetic suspension device.

  This type of electromagnetic suspension device includes, for example, a ball screw nut, a screw shaft that is screwed to the ball screw nut, and a motor that is coupled to the screw shaft, and the ball screw nut and screw when the shock absorber expands and contracts. The linear motion with the shaft is converted into the rotational motion of the screw shaft, and the rotational motion of the screw shaft can be transmitted to the rotor of the motor. The motor torque is controlled by the motor drive circuit to control the screw shaft and the ball screw. A load (control force) that suppresses the relative movement of the nut in the axial direction can be generated (see, for example, Patent Document 1).

  As a motor drive circuit for controlling the torque of the motor, for example, as shown in FIG. 11, switching elements 71 and 72, a switching element 73 to enable output torque control of a motor configured as a three-phase brushless motor. , 74, and arms 81, 82, 83 each having switching elements 75, 76 connected in series are connected to a plurality of power sources, and the switching elements 71, 72, 73, 74, 75, 76 are known. Is controlled to control the load generated by the electromagnetic suspension device (see Patent Documents 2 and 3).

Furthermore, there is also a proposal of a drive circuit for connecting motors in a linear motor type electromagnetic suspension device interposed between the left and right wheels of an automobile. In this proposed motor drive circuit, rolling of a vehicle body and vertical vibrations are proposed. The connection state between the motors is switched in accordance with the vibration mode, and the resistance value of the variable resistor is changed to control the current flowing through each motor (see Patent Document 4).
JP 2003-104025 A (Detailed description of the invention, FIG. 4 and FIG. 17) JP 2001-204194 A (Detailed Description of the Invention, FIG. 1) JP 2003-324986 A (Detailed Description of the Invention, FIG. 1) JP 2001-310736 A (paragraph numbers 0012 to 0037, FIGS. 1 and 3)

  And, in the electromagnetic suspension device as described above, since it is mounted on a vehicle, there is a demand for reducing the power consumption as much as possible. On the other hand, a sufficient load is applied even in a region where the stroke speed is low. There is a desire to make it possible.

  In order to achieve both power saving and load generation, it is necessary to reduce the resistance of the motor winding and the motor drive circuit as much as possible. Here, as shown in FIG. 12, the regenerative region (shaded area in FIG. 12) in which the power can be charged by the power generation of the motor is a stroke in the electromagnetic suspension device in a state where the windings of each phase of the motor are short-circuited from the origin. It is partitioned by the slope of the tangent drawn so as to contact the short-circuit characteristic that is the relationship between the speed and the load. The smaller the resistance, the greater the slope of the tangent and the larger the regeneration region. And if a load is generated with respect to the stroke speed in this regeneration region, the electromagnetic suspension device does not consume electric power.

  The rotational speed of the rotor of the motor is proportional to the relative speed of the screw shaft and the ball screw nut, that is, the stroke speed of the electromagnetic suspension device, and the output torque of the motor is proportional to the load of the electromagnetic suspension device. The short-circuit characteristic described above is obtained by converting the short-circuit characteristic, which is the relationship between the rotational speed and torque of the motor itself, into the relationship between the stroke speed and the load of the electromagnetic suspension device. In the present specification, the term “short-circuit characteristic” refers to the relationship between the stroke speed and the load of the electromagnetic suspension device when the motor is short-circuited as described above unless otherwise specified.

  As described above, in this electromagnetic suspension device, if the resistance is reduced, the regenerative region is expanded. Therefore, an opportunity to generate a necessary load in the regenerative region even if the stroke speed is low. As a result, power saving and load generation are both achieved.

  From the above advantages, it is better to reduce the resistance of the motor winding and the drive circuit. However, as shown in FIG. 12, when the stroke speed of the electromagnetic suspension device increases, Has a characteristic that the load reaches a certain peak at a certain stroke speed, but the load gradually decreases as the stroke speed increases thereafter. And has a property of being compressed toward the origin.

  In this electromagnetic suspension device, as the stroke speed continues to increase, the uncontrollable range (vertical line portion in FIG. 12) eventually increases, the load generation range gradually narrows, and only the load in accordance with the short-circuit characteristic is applied. It can no longer occur.

  Therefore, if the resistance is set to a small value as described above, there is a merit that it is possible to achieve both power saving and load generation in a region where the stroke speed is low, but it is difficult to generate a large load if the stroke speed is medium to high. In some cases, a sufficient load cannot be generated when the stroke speed is medium to high.

  In addition, the electromagnetic suspension device disclosed in Patent Document 4 exhibits a damping force due to the induced electromotive force generated in each of the left and right wheel motors. Even if the stroke speed is in the middle to high speed range and high damping force must be exhibited, sufficient damping force may not be exhibited depending on the vibration mode. .

  Therefore, the present invention was devised to improve the above-described problems, and the object of the present invention is to efficiently charge the power source and to provide a sufficient load even when the stroke speed is medium to high. An electromagnetic suspension device capable of generating

  In order to achieve the above-described object, the present invention provides an electromagnetic suspension device including one member, the other member that exhibits relative motion with respect to the one member, and a motor that can suppress at least the relative motion. And a short-circuit characteristic which is a relationship between a stroke speed and a load in a state where the motor is short-circuited by adjusting a resistance value of the variable resistor.

  According to the electromagnetic suspension device of the present invention, since the resistance value of the variable resistor is adjusted, it is possible to generate a load within the regeneration region, thereby making it possible to achieve both charging of the power source and generation of the necessary load. It is.

  In addition, when the stroke speed is in the middle to high speed range, the controllable area can be expanded by adjusting the resistance value of the variable resistor. Even if it cannot be generated, a large load can be generated.

  That is, according to this electromagnetic suspension device, the power source can be charged efficiently, and a sufficient load can be generated even when the stroke speed is medium to high.

  The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a diagram conceptually showing an electromagnetic suspension device according to an embodiment. FIG. 2 is a circuit diagram of the motor drive circuit. FIG. 3 is a diagram illustrating a regeneration region. FIG. 4 is a diagram illustrating the relationship between the change in resistance value of the variable resistor and the change in short-circuit characteristics. FIG. 5 is a diagram showing the frequency of each load on the expansion side and the contraction side generated by the shock absorber while the vehicle is running. FIG. 6 is a diagram showing the frequency of the expansion / contraction stroke speed of the shock absorber while the vehicle is running. FIG. 7 is a diagram illustrating a change in short-circuit characteristics. FIG. 8 is a diagram showing the relationship between the stroke speed and the load at which the power supply can be charged most efficiently. FIG. 9 is a diagram illustrating a relationship between a load and a regenerative current at an arbitrary stroke speed. FIG. 10 is a conceptual diagram of another electromagnetic suspension device.

  As shown in FIGS. 1 and 2, the electromagnetic suspension device according to the embodiment basically includes a screw shaft 1 that is one member, a ball screw nut 2 that exhibits relative motion with respect to the screw shaft 1, and a motor M. And variable resistors r1, r2 and r3 connected to the winding 12 of the motor M. More specifically, the variable resistors r1, r2, and r3 are respectively interposed between the windings 12 of the motor M and the motor drive circuit C. The electromagnetic suspension device includes resistances of the variable resistors r1, r2, and r3. By adjusting the value, the short-circuit characteristic T, which is the relationship between the stroke speed and the load when the motor M is short-circuited, is controlled.

  In the following, the screw shaft 1 is rotatably engaged with the ball screw nut 2 and the upper end in FIG. 1 of the screw shaft 1 is connected to the rotor R of the motor M. The other ball screw nut 2 is fixed to the upper end of a cylinder 4 into which the screw shaft 1 is inserted, and can be connected to one of the sprung member and the unsprung member of the vehicle via this cylinder 4. It is like that.

  The screw shaft 1 is rotatably connected to the other of the sprung member and the unsprung member of the vehicle. Specifically, the screw shaft 1 is provided on the other of the sprung member and the unsprung member of the vehicle. The motor M is fixed to the other of the sprung member and the unsprung member of the vehicle.

  Therefore, when the screw shaft 1 and the ball screw nut 2 exhibit a linear relative motion in the axial direction, the screw shaft 1 exhibits a rotational motion, and the rotational motion of the screw shaft 1 is transmitted to the rotor R of the motor M. It will be. Here, the rotational speed of the screw shaft 1 may be reduced through a reduction gear constituted by a gear mechanism or the like to transmit the rotational motion of the screw shaft 1 to the rotor R.

  When the screw shaft 1 and the ball screw nut 2 exhibit a linear relative motion in the axial direction, the ball screw nut 2 is used when the screw shaft 1 cannot be rotated and the ball screw nut 2 is rotated instead. The rotational motion of 2 may be transmitted to the rotor R of the motor M. Specifically, the screw shaft 1 is non-rotatably connected to one of the sprung member and unsprung member of the vehicle, and the other ball screw nut 2 is connected to the other of the sprung member and unsprung member of the vehicle with a ball bearing or the like. And the rotational movement of the ball screw nut 2 may be transmitted to the rotor R of the motor M via a gear mechanism, a friction wheel mechanism, or the like.

  In this case, the motor M includes a cylindrical frame 10, a stator that is an armature provided on the inner peripheral side of the frame 10, and a rotor R that is rotatably supported by the frame 10. Specifically, the stator includes an annular stator core 11 having a plurality of teeth, and a winding 12 in each of the U, V, and W phases wound around each tooth, The rotor R includes a shaft 13 and a driving magnet 14 mounted on the outer periphery of the intermediate portion of the shaft 13.

  Each of the U-phase, V-phase, and W-phase windings is Y-shaped at one end, but may be Δ-connected.

  And the drive magnet 14 is comprised with the magnet made into the block so that the predetermined number of poles can be implement | achieved, and it is embedded in the shaft 13, This motor M is made into the embedded magnet type. Of course, the drive magnet 14 is blocked so that a predetermined number of poles can be realized and bonded to the outer periphery of the shaft 13, or it is formed in an annular shape and dividedly magnetized so as to be fitted to the outer periphery of the shaft 13. May be.

  The motor M is equipped with a rotation angle sensor 15 for detecting the rotation angle of the rotor R. Specifically, for example, the rotation angle sensor 15 is attached to the resolver core provided on the shaft 13 and the frame 10. It only has to be constituted by a resolver stator facing the provided resolver core. In addition, an optical encoder may be adopted, and when a sensing magnet is provided in the rotor R, a Hall element, MR element, etc. The magnetic sensor may be provided on the frame 10.

  Further, a current sensor (not shown) for detecting the current flowing in each of the U, V, and W phase windings 12 of the motor M is separately provided. Entered.

  In order to control the current flowing through each winding 12 of the motor M, specifically, each U, V, W phase winding 12 is connected to the motor drive circuit C shown in FIG.

  As shown in FIG. 2, the motor drive circuit C for driving the motor M includes an arm A1 in which switching elements S1 and S4 are connected in series, an arm A2 in which switching elements S2 and S5 are connected in series, and a switching element S3. , S6 are connected in series, and the arms A1, A2, A3 are connected in parallel, and the switching elements S1, S4, S2, S5, S3, S6 of the arms A1, A2, A3 are connected in parallel. The output terminals P1, P2 and P3 connected to the motor M are between the terminals.

 Further, the upper connection point in FIG. 2 of each arm A1, A2, A3 is connected to a power source E such as a vehicle battery, and the lower connection point in FIG. 2 is grounded.

 The arm A1 is configured by connecting two switching elements S1 and S4 in series. An output terminal P1 is provided between the switching elements S1 and S4 of the arm A1, and the output terminal P1 is connected to a motor. It is connected to the U phase of the M winding 12.

  The other arms A2 and A3 have the same configuration as the arm A1, and their output terminals P2 and P3 are connected to the V phase and W phase of the winding 12 of the motor M, respectively.

  A variable resistor r1 is interposed between the output terminal P1 and the U-phase winding 12, and a variable resistor r2 is provided between the output terminal P2 and the V-phase winding 12. A variable resistor r3 is interposed between P3 and the W-phase winding 12 respectively.

  Specifically, the variable resistors r1, r2, and r3 may be of a volume type. For example, a drive source such as a motor is used to adjust the resistance values of the variable resistors r1, r2, and r3. do it. The resistance values of the variable resistors r1, r2, and r3 may be adjusted by operating the drive source with the control device 20 described above.

  In this case, since the motor M is configured as a three-phase brushless motor, the three variable resistors r1, r2, and r3 are provided. However, when the number of phases of the winding 12 is different, the variable resistor The number corresponding to the number may be provided.

  Further, the above-described variable resistors r1, r2, and r3 are mounted on the vehicle, but are provided at locations where the wind is good when the vehicle is running, that is, locations where air cooling is possible. Specifically, it is provided inside the front grill after being sealed.

  Returning to this motor drive circuit C, for example, when the switching element S1 and the switching element S5 are turned on, currents can flow in the U phase and the V phase of the winding of the motor M. If the switching elements S1, S2, S3 of one arm A1, A2, A3 and one switching element S4, S5, S6 of the other two arms A1, A2, A3 are turned on, the winding of the motor M More specifically, the controller 20 controls the opening and closing of the motor M so that a rotating magnetic field is formed in each of the windings 12 of the UVW phase.

  As described above, since the current supply from the power source E to the winding 12 is always performed through the variable resistors r1, r2, and r3, the current is looped by adjusting the resistance values of the variable resistors r1, r2, and r3. It is possible to adjust the resistance values of the windings 12 and the motor drive circuit C. Further, as described above, since the variable resistors r1, r2, and r3 are mounted at locations where the vehicle can be air-cooled, an increase in temperature due to power consumption by the variable resistors r1, r2, and r3 is suppressed, and the variable resistors The performance deterioration due to the temperature rise of r1, r2, and r3 is prevented, so that the current flowing through each winding 12 can be stably controlled.

  The switching element S1 is a MOSFET (Metal Oxide Semiconductor, FET: Field Effect Transistor), and the MOSFET includes a parasitic diode K1 that connects the source electrode and the drain electrode.

  The other switching elements S2, S3, S4, S5, and S6 have the same configuration as that of the switching element S1, are respectively MOSFETs, and incorporate parasitic diodes K2, K3, K4, K5, and K6.

  These parasitic diodes K1, K2, K3, K4, K5, and K6 are flywheel diodes that absorb a surge generated in the winding of the motor M when the switching elements S1, S2, S3, S4, S5, and S6 are turned off. Functioning, the switching elements S1, S2, S3, S4, S5 and S6 can be protected. A switching element other than the MOSFET may be used.

  The switching elements S1, S2, S3, S4, S5, and S6 switch the energization phase of the control device 20 based on the rotation angle of the rotor detected by the rotation angle sensor 15 and the current flowing through each winding, respectively. The motor M is driven by applying a voltage to the gate electrode by the control to control the opening and closing, and the output torque and the rotor rotational speed of the motor M are controlled by the PWM control.

  In addition to PWM control, control using a continuous modulation method such as PAM (Pulse Amplitude Modulation) or PPM (Pulse Position Modulation) or a discontinuous modulation method such as a PNM (Pulse Number Modulation) circuit may be performed.

  In the motor drive circuit C, during the PWM control, each of the switching elements S1, S2, S3, S4, S5, and S6 has a predetermined pulse width period that realizes a predetermined duty ratio under the control of the control device 20, respectively. The control is performed so that the torque generated by the motor M is turned on, and the torque generated by the motor M is thereby controlled.

  Therefore, in this electromagnetic suspension device, since the drive source is the motor M, when the motor M is driven by being supplied with electric energy via the motor drive circuit C, the screw shaft 1 is generated by the torque generated by the motor M. Can be rotated to positively move the screw shaft 1 and the ball screw nut 2 relatively linearly, that is, the function as an actuator can be exhibited.

  In addition, when a rotational motion is forcibly input from the screw shaft 1, the motor M generates a magnetic field due to a current flowing through the winding 12 by the induced electromotive force or the power from the power source E, and an electromagnetic force is generated. Since the torque that suppresses the rotational movement of the screw shaft 1 is generated, it functions to suppress the relative linear movement of the screw shaft 1 and the ball screw nut 2. That is, in this case, the torque generated by the electric power obtained by the motor M regenerating kinetic energy input from the outside and converting it into electric energy, or by the electric power supplied from the power source in addition to this regeneration. Thus, the relative linear motion of the screw shaft 1 and the ball screw nut 2 can be suppressed.

  Furthermore, this electromagnetic suspension device can cause the motor M to function as both an actuator and a generator, so that the relative linear motion of the screw shaft 1 and the ball screw nut 2 can be suppressed, and at the same time, the function as an actuator can be utilized. Thus, the posture control of the vehicle body of the vehicle can be performed at the same time, so that the function as an active suspension can be exhibited.

  The control device 20 is not shown as hardware, but specifically includes, for example, an amplifier for amplifying signals output from the current sensor, the rotation angle sensor 15 and various sensors necessary for vehicle body posture control. A converter that converts an analog signal into a digital signal, a storage device such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a crystal oscillator, and a bus line that connects these And calculating a load to be generated in the electromagnetic suspension device based on a predetermined control law for vehicle body posture control, and each switching element S1, S2, S3, S4, S5 of the motor drive circuit C. In S6, control signal as PWM pulse signal For example, further, giving a control signal to the drive source of the variable resistor r1, r2, r3 described above, and is capable of generating a load that is the calculation to the electromagnetic suspension system.

  Then, the control processing procedure for PWM control of the motor M by adjusting the switching elements S1, S2, S3, S4, S5, and S6 of the motor drive circuit C and the adjustment of the resistance values of the variable resistors r1, r2, and r3 The processing procedure related to this is stored in advance in a ROM or other storage device as a program.

  The control device 20 performs three-phase to two-phase conversion processing, calculates each d-phase and q-phase current target values in accordance with a control law in vehicle body posture control, and uses each current target value as a torque command. A current loop process is performed to perform proportional-integral control of the motor M. Note that not only proportional-integral control but also proportional-integral-derivative control may be performed.

  Moreover, the control apparatus 20 may be integrated into ECU mounted in a vehicle as this hardware.

  By the way, in this electromagnetic suspension device, when the rotor R of the motor M rotates, the magnetic flux of the driving magnet 14 of the rotor R crosses the winding 12, so that an induced electromotive force is generated in the winding 12 and a regenerative current flows. The current due to the power source E and the regenerative current due to the induced electromotive force flow through the winding 12, but the regenerative operation capable of recharging the power source E by the induced electromotive force of the winding 12 of the motor M can be performed. The region K is a range surrounded by the stroke speed axis and the tangent line S that passes through the origin and is in contact with the stroke speed and load curve in the short circuit characteristic T, and can be determined by the short circuit characteristic T as shown in FIG.

  Here, the stroke speed is the linear relative movement speed of the ball screw nut 2 in the axial direction with respect to the screw shaft 1, and the load is the straight line between the screw shaft 1 and the ball screw nut 2 generated by the torque generated by the motor M. It is a force that suppresses or promotes relative movement.

  In FIG. 3, on the stroke speed axis, if the stroke speed in the direction in which the electromagnetic suspension device contracts is a positive value for the sake of convenience, the right side of the origin indicates the stroke speed in the contraction direction, and the electromagnetic suspension device extends. If the stroke speed is a negative value for convenience, the left side of the origin indicates the stroke speed in the extension direction. On the other hand, if the load in the direction of extending the electromagnetic suspension device is positive for the load axis for the sake of convenience, the portion above the origin indicates the load in the expansion direction, and the load in the direction of contracting the electromagnetic suspension device is negative for convenience. The value below the origin indicates the load in the contraction direction.

  Therefore, in FIG. 3, the first quadrant shows a state in which the electromagnetic suspension device strokes in the contracting direction, but generates a load that suppresses the stroke, and the second quadrant shows the electromagnetic suspension device. Indicates a state in which a load is generated in a direction that promotes the stroke while a stroke is generated in the extending direction, and the third quadrant is a load that suppresses the stroke in the extending direction. The fourth quadrant shows a state in which a load that promotes the stroke is generated while the stroke is in the contracting direction.

  As described above, the regenerative region K is a range (hatched portion in FIG. 3) surrounded by the stroke speed axis and the tangent line S passing through the origin and in contact with the stroke speed and load curve in the short circuit characteristic T. Furthermore, since the inclination at the tangent S is a value determined by the torque constant of the motor M, the regeneration region K can also be determined by setting the torque constant. Note that a horizontal line a that determines the maximum or minimum load of each quadrant in FIG. 3 is a line that divides an area where load can be generated and an area where load cannot be determined determined by the maximum voltage when the motor M is controlled by PWM control. In addition, the curve b is also a line that divides a region where a load can be generated from a region where a load can not be generated.

  The short-circuit characteristic T described above draws a curve in which the load reaches a peak at a certain stroke speed as the stroke speed is increased, and the load gradually decreases as the stroke speed increases thereafter. . That is, until the load peak is reached, the current obtained by power generation caused by forcibly rotating the rotor R of the motor M flows through the windings 12 of each phase so as to effectively generate torque that suppresses the stroke. However, when the stroke speed is increased to the extent that the load peak is exceeded, the reactive current that does not contribute to torque increases and the load decreases. This does not affect the regeneration region K.

  The short-circuit characteristic T can be compressed and expanded along the stroke speed axis by changing the resistance values of the variable resistors r1, r2, and r3. This is because, when the stroke speed is constant, if the resistance value is decreased, the current flowing through each winding 12 is increased. Conversely, if the resistance value is increased, the current flowing through each winding 12 is decreased. If it is made smaller, the magnetic field generated by each winding 12 becomes larger, the torque generated by the motor M with respect to the stroke speed becomes larger, and the load generated by the electromagnetic suspension device becomes larger. Conversely, if the resistance value is increased, each winding 12 becomes This is because the generated magnetic field is reduced, the torque generated by the motor M with respect to the stroke speed is reduced, and the load generated by the electromagnetic suspension device is reduced.

  Therefore, if the resistance values of the variable resistors r1, r2, and r3 are changed, the torque generated by the motor M can be changed. As shown in FIG. 4, when the resistance value is increased, the maximum value of the load is changed. When the short circuit characteristic T is extended along the stroke speed axis without reducing the resistance value, conversely, when the resistance value is reduced, the short circuit characteristic T is moved along the stroke speed axis to the origin side without changing the maximum value of the load. Therefore, it is possible to control the short-circuit characteristic T by changing the resistance values of the variable resistors r1, r2, and r3, thereby changing the slope of the tangent line S.

  In this electromagnetic suspension device, basically, the resistance values of the variable resistors r1, r2, and r3 are adjusted based on the stroke speed. Specifically, when the stroke speed is low, the resistance values of the variable resistances r1, r2, and r3 are adjusted to be small, and the short-circuit characteristic T is drawn toward the origin along the stroke speed axis to tangentially The slope of S is increased and the regeneration area K is expanded.

  At this time, the resistance value is adjusted by the operation of the drive source of the control device 20 so that the load to be generated with respect to the stroke speed calculated by the control device 20 is in the regeneration region K.

  Therefore, according to this electromagnetic suspension device, a load can be generated in the regenerative region K, whereby it is possible to achieve both charging of the power source E and generation of a necessary load.

  Moreover, since the regeneration area | region K can be expanded according to stroke speed, the opportunity to charge the power supply E can be increased, and also in this point, power saving is achieved.

  As shown in FIG. 5, a general passive damper generates a load frequently in the range of 200N to 1000N centering on approximately 600N on the extension side, and on the contraction side, as shown in FIG. Loads are frequently generated in the range of 0N to 600N around 300N. Furthermore, the expansion / contraction stroke speed that appears at a high frequency while the vehicle is running is generally within the range of 0.1 m / s as shown in FIG.

  As can be understood from the above, the frequently used stroke speed range in expansion and contraction of a general passive damper is within a range of 0.1 m / s, and the frequently used load is within 1000 N.

  Therefore, in this electromagnetic suspension device, a load of 1000 N is set for a stroke speed of 0.1 m / s in the regenerative region K in a state where the resistance values of the variable resistors r1, r2, and r3 are minimized. Then, when the vehicle travels on a paved road, it is possible to charge the power source E approximately.

  Therefore, in the case where the electromagnetic suspension device is frequently used, when the electromagnetic suspension device is frequently used, the power source E is always regenerated and the power source E is not consumed and the power of the power source E is not consumed. Power saving can be ensured, and the situation where the power source E is raised due to the operation of the electromagnetic suspension device can be prevented. Further, the present invention is optimal for a vehicle using a drive source such as an electric vehicle as a motor.

  That is, since the regeneration region K in the stroke speed range that frequently appears during vehicle travel is increased, the opportunity to charge the power source E by regeneration can be increased, and power saving can be ensured. .

  In addition, by setting as described above, a sufficiently large load can be generated in the regenerative region K even if vibration with a relatively fast stroke speed of about 0.3 m / s is input. An electromagnetic suspension device.

  On the other hand, when the stroke speed reaches the middle-high speed region, the resistance values of the variable resistors r1, r2, r3 are increased according to the stroke speed. Then, as the resistance value increases, the magnetic field generated by each winding 12 becomes smaller, and the short-circuit characteristic T changes so as to be extended along the stroke speed axis as described above.

  Therefore, even if the induced electromotive force generated in the winding 12 of the motor M becomes a stroke speed exceeding the voltage of the power supply E and the load corresponding to the short-circuit characteristic T cannot be generated, the short-circuit characteristic can be adjusted by adjusting the resistance value. 7, the short-circuit characteristic indicated by the dotted line Y in FIG. 7 is changed to the short-circuit characteristic indicated by the solid line Z, and a large load can be generated.

  That is, according to this electromagnetic suspension device, the power source can be charged efficiently, and a sufficient load can be generated even when the stroke speed is medium to high.

  In addition, from the above, since the control range of the load with respect to the stroke speed in the electromagnetic suspension device can be expanded by adjusting the resistance value, the load is increased with respect to the load that the electromagnetic suspension device should generate. A situation in which shortage occurs is prevented, the ride comfort in the vehicle can be improved, and the vehicle body posture control can be reliably performed because there is no load shortage.

  In the above description, the resistance values of the variable resistors r1, r2, and r3 are adjusted so as to increase according to the stroke speed. However, when the stroke speed becomes medium to high, sufficient load is generated. In general, the regeneration region K is increased with the aim of charging efficiency of the power source E at a low stroke speed, and the resistance value of the variable resistor is increased when the induced electromotive force of the motor M reaches a predetermined voltage. May be. In this case as well, control for gradually increasing the resistance values of the variable resistors r1, r2, and r3 with respect to the increase in the stroke speed may be performed together.

  If the predetermined voltage is set to the voltage of the power supply E or set to be smaller than the voltage of the power supply E, the stroke speed increases and the induced electromotive force of the motor M exceeds or exceeds the voltage of the power supply E. When there is, it is prevented that the ride comfort in the vehicle is impaired due to insufficient load. In particular, when the predetermined voltage is set to be equal to or lower than the voltage of the power supply E, a sufficient load can be activated against a sudden increase in stroke speed. Even in such a case, the generated load of the electromagnetic suspension device is reduced. It is possible to avoid a situation where there is a shortage.

  In addition to setting the predetermined voltage to the power supply voltage, the value to which the predetermined voltage is set varies depending on the purpose of use of the vehicle, etc. It is good to adjust according to the vehicle.

  Further, when the induced electromotive force of the motor M reaches a predetermined voltage, the resistance values of the variable resistors r1, r2, and r3 are increased, so that it is difficult to frequently adjust the resistance values of the variable resistors r1, r2, and r3. Therefore, the adjustment of the resistance values of the variable resistors r1, r2, and r3 is simplified, and the regeneration region K can be normally expanded, so that the charging opportunity loss of the power source E can be suppressed.

  By the way, considering the charging efficiency of the power supply E, it is ideal to generate a load that can charge the power supply E most efficiently within the regeneration region K with respect to the stroke speed.

  Here, as shown in FIG. 8, the line that can charge the power source E most efficiently passes through the origin and is half of the slope of the tangent line S that is in contact with the stroke speed and load curve in the short-circuit characteristic T. A straight line A passing through the origin with an inclination of.

  The relationship between the load generated at an arbitrary stroke speed and the regenerative current is as shown in FIG. 9, and the regenerative current is the load at the midpoint between the minimum value and maximum value of the load at which the regenerative current is zero. Is the maximum.

  The minimum value and the maximum value of the load at which the regenerative current is 0 indicate the minimum value and the maximum value of the load in the regenerative region K generated for an arbitrary stroke speed, respectively. Specifically, since the minimum value of the load at which the regenerative current is 0 is the load on the stroke speed axis in FIG. 3, the value is 0, and the maximum value of the load at which the other regenerative current is 0 is The value of the load on the tangent line S in FIG.

  That is, the maximum regenerative current is the load at the midpoint between the minimum value and the maximum value of the load at which the regenerative current is 0, as described above, on the straight line A having a ½ slope of the tangent line S. When a load is generated at, charging efficiency of the power source E is maximized.

  Therefore, if the load generated with respect to the stroke speed is adjusted to be on the straight line A by adjusting the resistance values of the variable resistors r1, r2, and r3, the charging efficiency of the power source E is maximized.

  Specifically, the slope of the tangent S is adjusted by adjusting the resistance values of the variable resistors r1, r2, and r3 to control the short-circuit characteristic T, that is, the slope of the straight line A is adjusted, and the stroke speed is adjusted. The load to be generated is controlled so as to be on the straight line A.

  In this way, by adjusting the resistance values of the variable resistors r1, r2, and r3 and controlling the short-circuit characteristic T, the electromagnetic suspension device can generate a load to be generated and improve the riding comfort in the vehicle. The charging efficiency of the power source E can be maximized, and power saving can be further measured.

  Moreover, since it becomes possible to charge the power supply E most efficiently, even if the vehicle is left parked for a long time and the voltage of the power supply E drops, the power supply E was originally exhibited. The voltage can be recovered quickly.

  In addition, the electromagnetic suspension device, like the other electromagnetic suspension devices shown in FIG. 10, has at least a cylinder 31 that is one member, a rod 32 that is the other member that exhibits relative motion with respect to the tube 31, and at least restrains the relative motion. You may make it comprise with possible motor M2.

  Specifically, the cylinder 31 is connected to one of a sprung member and an unsprung member of the vehicle, and a rod 32 connected to the other of the sprung member and the unsprung member of the vehicle is passed through the cylinder 31. .

  The motor M2 includes a driving magnet 33 that is mounted on the outer periphery of the rod 32 so that S poles and N poles appear alternately in the axial direction, and a winding 34 that faces the driving magnet 33 in the cylinder 31. The windings 34 are arranged so that the U, V, and W phases are alternately arranged along the axial direction of the cylinder 31 over a predetermined length.

  Note that the winding 34 provided in the cylinder 31 is formed in an annular shape, and at least the inner peripheral side is coated with resin or the like. The inner periphery of the winding 34 and the outer periphery of the rod 32 or the drive magnet 33 An annular bearing (not shown) is arranged between them directly or indirectly, and the shaft 32 is prevented from being shaken with respect to the cylinder 31.

  That is, in this other electromagnetic suspension device, a so-called linear motor type configuration in which the drive magnet 33 moves relative to the winding 34 when the rod 32 advances and retreats relative to the cylinder 31 and exhibits relative motion. Even in the other electromagnetic suspension devices, similarly to the electromagnetic suspension device in the above-described embodiment, the motor M2 functions as both a motor and a generator. Therefore, if the above-described variable resistors r1, r2, and r3 are provided, the same effects as those of the electromagnetic suspension device according to the embodiment can be achieved by adjusting the resistance values.

  This is the end of the description of the embodiment of the present invention, but the scope of the present invention is of course not limited to the details shown or described.

It is the figure which showed notionally the electromagnetic suspension apparatus in one embodiment. It is a circuit diagram of a motor drive circuit. It is a figure which shows a regeneration area | region. It is the figure which showed the relationship between the change of the resistance value of a variable resistance, and the change of a short circuit characteristic. It is a figure which shows the frequency of each load of the expansion | extension side and shrinkage | contraction side which a buffer produces | generates while driving | running | working a vehicle. It is a figure which shows the frequency of the expansion-contraction stroke speed of the buffer during driving | running | working of a vehicle. It is a figure which shows the change of a short circuit characteristic. It is a figure which shows the relationship between the stroke speed and load which can charge a power supply most efficiently. It is a figure which shows the relationship between the load and regenerative current in arbitrary stroke speeds. It is a conceptual diagram of another electromagnetic suspension apparatus. It is a figure which shows the conventional motor drive circuit. It is a figure which shows the regeneration area | region and uncontrollable area | region of the conventional electromagnetic suspension apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Screw shaft which is one member 2 Ball screw nut 10 which is the other member Frame 11 Stator core 12, 33 Winding 13 Shaft 14, 34 Driving magnet 15 Rotation angle sensor 20 Control device 31 Tube 32 which is one member Rod S1 which is the other member , S2, S3, S4, S5, S6 Switching element A1, A2, A3 Arm B Bypass C Motor drive circuit E Power supply K1, K2, K3, K4, K5, K6 Parasitic diode L Relay M Motor P1, P2, P3 Output terminal R Stator r1, r2, r3 Variable resistance

Claims (11)

In an electromagnetic suspension device including one member, the other member that exhibits relative motion with respect to the one member, and a motor that can suppress at least the relative motion, the electromagnetic suspension device includes a variable resistor connected to a winding of the motor. An electromagnetic suspension device that controls a short-circuit characteristic that is a relationship between a stroke speed and a load in a state where a motor is short-circuited by adjusting a resistance value. 2. The electromagnetic suspension device according to claim 1, wherein the variable resistor is interposed between each winding of the motor and the motor drive circuit. The electromagnetic suspension apparatus according to claim 1 or 2, wherein the variable resistor is installed at a location where the vehicle can be air-cooled while the vehicle is running. 4. The electromagnetic suspension device according to claim 1, wherein the resistance value of the variable resistor is adjusted based on the stroke speed. 5. The electromagnetic suspension device according to claim 1, wherein the resistance value of the variable resistor is increased with respect to an increase in stroke speed. 6. The electromagnetic suspension device according to claim 1, wherein the resistance value of the variable resistor is adjusted so as to generate a load in a regeneration region where the power supply of the motor can be charged with respect to the stroke speed. 7. The electromagnetic suspension device according to claim 1, wherein the resistance value of the variable resistor is increased when the induced electromotive force of the motor reaches a predetermined voltage. 8. The electromagnetic suspension device according to claim 7, wherein the predetermined voltage is a voltage of a power source that supplies electric power to the motor. The electromagnetic suspension device according to any one of claims 1 to 8, wherein the resistance value of the variable resistor is adjusted so as to maximize a regenerative current generated by the power generation of the motor with respect to the stroke speed. The resistance value of the variable resistor can be adjusted so that a point where the generated load is 1000 N at a stroke speed of 0.1 m / s is included in the regenerative region where the power can be charged by the power generation of the motor. The electromagnetic suspension apparatus according to claim 1, wherein the electromagnetic suspension apparatus is characterized in that: The one member exhibits a rotational motion when the other member exhibits a linear relative motion with respect to the one member and the other member, and the rotational motion of the one member is transmitted to the motor. The electromagnetic suspension device described.

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