JP2001280417A - Electromagnetic suspension device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heighten a flexural rigidity not to increase its outside diameter in an electromagnetic suspension device. SOLUTION: A cylindrical movable bobbin 15, a working rod, is slidably supported by bearings 16 installed in the inner circle part of a cylindrical outside yoke 12. Multiple coils 17 are fixed in the inner circle part of the movable bobbin 15. Permanent magnets 18, placed facing to the inner circle surface of the coils 17, are fixed on a center yoke 13 set into the outside yoke 12 together and lengthways. Against the stroke of the movable bobbin 15, damping force or thrust is acted by electromagnetic force of the coils 17 and the permanent magnets 18. As supporting the movable bobbin 15 by the outside yoke 12 of the biggest diameter, the electromagnetic suspension device can extremely heighten the flexural rigidity without increasing its outside diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic suspension device which is mounted on an automobile, a railway car, a structure, a building, and the like, and controls vibration by an electromagnetic force.

[0002]

2. Description of the Related Art An example of a conventional electromagnetic suspension device will be described with reference to FIG. As shown in FIG. 8, the electromagnetic suspension device 1 includes a main body member 4 having a double cylindrical structure in which a cylindrical center yoke 3 is disposed inside a cylindrical outer yoke 2, and an outer yoke 2 and a center yoke 3. And a cylindrical movable bobbin 5 inserted therebetween.

The movable bobbin 5 is slidably supported by a bearing 6 mounted on the outer periphery of the center yoke 4 so as to be able to expand and contract with respect to the main body member 4 (see FIG.
1 shows a state where the movable bobbin 5 is most shortened). A plurality of coils 7 are wound around the outer periphery of the movable bobbin 5 over substantially the entire length thereof. Large diameter part of outer yoke 2
A permanent magnet 9 arranged in an annular shape facing the coil 6 is fixed to the inner peripheral portion of the coil 8. In FIG. 1, reference numeral 10 denotes a protective cover.

[0004] With this configuration, the main body member 4 and the movable bobbin 5 are moved by the electromagnetic force acting between the permanent magnet 9 and the coil 7.
Relative displacement (expansion and contraction) can be controlled. In other words, by controlling the current supplied to the coil 7, the coil 7 and the permanent magnet 9 can be operated as a linear motor to generate a thrust on the movable bobbin 5, and the electromagnetic suspension device 1 can function as an actuator. Can be. In addition, by moving the movable bobbin 5 to operate the coil 7 and the permanent magnet 9 as a generator and controlling the current flowing through the coil 7 by a variable resistor or on / off of a switch, A damping force can be generated.

[0005] By controlling the current of the coil 7 in this manner, the thrust or damping force acting on the movable bobbin 5 can be easily controlled. For example, the electromagnetic suspension device 1 can be mounted on a vehicle suspension. The electromagnetic suspension device 1 according to acceleration, vibration, etc. generated in the vehicle body using various sensors and controllers, etc.
By controlling the damping force and the stroke of the vehicle in real time, posture control and vibration control (so-called active suspension control and active damper control) of the vehicle body can be performed.

[0006]

However, the conventional electromagnetic suspension device 1 has the following problems. Since the movable bobbin 5 is supported by the small-diameter center yoke 3, the bending rigidity is low. If the diameter of the center yoke 3 is increased in order to increase the bending rigidity, the entire device becomes large.

Since the permanent magnet 9 is fixed to the outer yoke 8, if the size of the permanent magnet 9 is increased in order to secure a sufficient electromagnetic force, the outer diameter of the entire device becomes larger. Also, since a magnetic circuit is constituted by the outer yoke 8, in order to prevent magnetic saturation and leakage of magnetic flux to the outside,
The thickness of the outer yoke 8 cannot be reduced, and it is difficult to reduce the size of the entire device.

[0008] The present invention has been made in view of the above points, and has as its object to provide an electromagnetic suspension device capable of obtaining high bending rigidity without increasing the outer diameter.

[0009]

According to another aspect of the present invention, there is provided an electromagnetic suspension having a cylindrical outer yoke and an integrally erected inside the outer yoke along an axial direction thereof. A center yoke, a cylindrical movable bobbin slidably supported inside the outer yoke, a coil fixed to an inner peripheral portion of the movable bobbin, and a coil disposed facing the inner peripheral portion of the coil. And a permanent magnet fixed to the center yoke.

With this configuration, the movable bobbin is supported by the large-diameter outer yoke, so that the bending rigidity is increased. Further, by disposing the coil outside the permanent magnet, the diameter of the coil can be increased.

According to a second aspect of the present invention, there is provided an electromagnetic suspension device according to the first aspect, wherein a cylinder formed in the center yoke and filled with an oil liquid is slidably fitted in the cylinder. A piston, a piston rod connected to the piston and extending to the outside of the cylinder and connected to the movable bobbin, and a damping force generated by controlling a flow of an oil liquid generated by sliding of the piston. And a damping force generating means.

With this configuration, in addition to the electromagnetic force generated by the coil and the permanent magnet, a damping force can be generated by the flow of the oil liquid.

According to a third aspect of the present invention, in the electromagnetic suspension device according to the first or second aspect, the electromagnetic force acting between the coil and the permanent magnet is controlled by controlling a current flowing through the coil. And controlling the movable bobbin to generate a thrust or a damping force.

[0014] With this configuration, the damping force or thrust of the movable bobbin can be controlled by controlling the current flowing through the coil.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. A first embodiment of the present invention will be described with reference to FIGS. 1 to 4 and FIG. As shown in FIGS. 1 and 2, the electromagnetic suspension device 11 has a double-cylinder main body member 14 including a bottomed cylindrical outer yoke 12 and a center yoke 13 concentrically provided inside the outer yoke 12.
And a cylindrical movable bobbin 15 inserted between the outer yoke 12 and the center yoke 13.

The movable bobbin 15 is slidably supported by a bearing 16 mounted on the inner periphery of the outer yoke 12.
An operating rod that can extend and contract with respect to the main body member 14 is configured. In the present embodiment, the outer yoke 12 has a divided structure including a distal end portion 12a to which the bearing 16 is attached and a base end portion 12b formed integrally with the center yoke 13. A plurality of coils 17 are attached to the inner periphery of the movable bobbin 15 along the axial direction. Multiple coils 17
Are cylindrically arranged over substantially the entire length of the movable bobbin 15.

A movable bobbin is provided around the center yoke 13.
A plurality of cylindrically arranged permanent magnets 18 are attached to face the 15 coils 17. Then, as shown in FIG. 3, the outer yoke 12, the center yoke 13, the movable bobbin 1
5, a magnetic circuit is constituted by the coil 17 and the permanent magnet. A sufficiently small gap C is provided between the coil 17 and the permanent magnet 18.

The permanent magnet 18 is disposed on the distal end side of the center yoke 13 over about one half of its entire length, whereby the substantial movable range of the movable bobbin 15 (all the permanent magnets 1
The range in which the coil 8 faces the coil 17) is defined. Note that a stroke end stopper (not shown) is provided to restrict the actual movable range of the movable bobbin 15 to this range. FIG. 1 shows a state where the movable bobbin 15 is most shortened.

Next, the operation of the embodiment constructed as described above will be described. Working rod or movable bobbin 15
When a stroke occurs, an induced electromotive force is generated in the coil 17 by the relative movement between the coil 17 and the permanent magnet 18 (acting as a generator), and the stroke of the movable bobbin 15 is
A damping force is generated according to the current flowing through the coil 17. At this time, for example, the damping force can be controlled by controlling the current flowing through the coil 17 with a variable resistor, or controlling the ON / OFF of the circuit by duty.

Further, by applying a current to the coil 17 in accordance with the relative position between the coil 17 and the permanent magnet 18, a thrust is generated on the movable bobbin 15 by electromagnetic force (operating as a linear motor). Thus, the thrust can be controlled, and the electromagnetic suspension device 11 can be operated as an actuator.

The coil 17 is fixed inside the movable bobbin 15,
The permanent magnet 18 is arranged inside the coil 17 and the center yoke 13
The outer yoke 12 with the largest outer diameter
Since the movable bobbin 15 can be supported by the bearing 16 provided in the electromagnetic suspension device 11, the bending rigidity of the electromagnetic suspension device 11 can be greatly improved.

Since the movable bobbin 15 is provided outside the permanent magnet 18 and the coil 17, the outer diameter of the movable bobbin 15 can be increased and its bending rigidity can be increased. Movable bobbin
Since the coil 17 is protected by 15, the conventional protective cover is not required. Further, by disposing the coil 17 outside the permanent magnet 18, the diameter of the coil 17 can be easily increased, the electromagnetic force can be increased, and the cooling of the coil 17 can be promoted.

In order to prevent leakage of magnetic flux to the outside due to magnetic saturation in the magnetic circuit, it is necessary to make the thickness of the members constituting the magnetic circuit sufficiently large. However, the permanent magnet 18 is arranged inside the coil. Since the center yoke 13 is attached to the hollow center yoke 13, the required magnetic path can be secured without increasing the outer diameter of the electromagnetic suspension device 11 by increasing the thickness of the center yoke 13.

Since only axial thrust and damping force act on the center yoke 13 and no bending stress acts on the center yoke 13, the portion of the center yoke 13 that does not constitute a magnetic circuit should be made thinner. And lightening can be achieved.

Further, in general, the coil 17 can have higher dimensional accuracy on the inner peripheral side than on the outer peripheral side for manufacturing reasons. However, the permanent magnet 18 is opposed to the inner peripheral side of the coil 17. Therefore, the accuracy of these gaps C can be enhanced, a stable strong electromagnetic force can be obtained, and stable damping force and thrust can be generated.

Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. The second embodiment differs from the first embodiment in that a hydraulic damper is incorporated inside the center yoke. Therefore, the same reference numerals are used for the same parts as those in the other first embodiment. In addition, only different parts will be described in detail.

As shown in FIG. 4, in the electromagnetic suspension device 19 of the second embodiment, a piston 21 is slidably fitted in a cylinder 20 formed inside a center yoke 13,
The interior of the cylinder 20 is moved by the piston 21 to the cylinder upper chamber 20.
a and a cylinder lower chamber 20b. Piston 2
1, one end of a piston rod 22 is connected, and the other end of the piston rod 22 is inserted through a rod guide 23 and an oil seal 24 mounted on an upper end of the cylinder 20, and extends to the outside of the cylinder 20. The tip is connected to the movable bobbin 15.

A cylindrical reservoir chamber 25 is provided on the outer peripheral portion of the center yoke 13 on the base end side where the permanent magnet 18 is not mounted.
Is formed, and the reservoir chamber 25 communicates with the cylinder lower chamber 20b via an oil passage 26 (orifice). Cylinder upper and lower chamber 2
An oil liquid is sealed in 0a and 20b, and an oil liquid and a gas are sealed in the reservoir chamber 25. An oil passage 27 is provided in the piston 21 to communicate between the cylinder upper and lower chambers 20a and 20b.
A damping force generating means comprising an orifice, a disc valve and the like for controlling the flow of the oil liquid to generate a damping force.
(Not shown).

With this structure, the hydraulic fluid in the cylinder upper and lower chambers 20a and 20b flows through the oil passage 27 of the piston 21 to generate a damping force due to the stroke of the piston rod 22 accompanying the stroke of the movable bobbin 15. . The change in volume in the cylinder 20 caused by the intrusion and retreat of the piston rod 22 is caused by flowing the oil liquid between the cylinder lower chamber 20b and the reservoir chamber 25 through the oil passage 26, thereby displacing the gas in the reservoir chamber 25. It is absorbed by compressing and expanding.

Thus, in addition to the damping force by the electromagnetic force, the damping force can be generated by the flow of the oil liquid, so that the load on the coil 17 and the permanent magnet 18 can be reduced, and the size of the electromagnetic suspension device 19 can be reduced. can do. In this case, since the hydraulic damper is disposed inside the center yoke 13, space efficiency is excellent and it is advantageous to promote downsizing. Further, even when the damping force due to the electromagnetic force is excessively reduced due to the disconnection of the coil 17 or the like, the damping force can be maintained by the hydraulic damper.

The piston 21 is provided with only an oil passage 27. By providing different oil passages on the extension side and the contraction side, different damping force characteristics can be obtained on the extension side and the contraction side. Can also.

Next, the damping force characteristics of the electromagnetic suspension device 19 will be described with reference to FIG. When the resistance to the coil 17 is constant, the damping force generated by the electromagnetic force is substantially proportional to the stroke speed as shown in FIG.
On the other hand, the damping force generated by the hydraulic damper is substantially proportional to the square of the piston speed as shown in FIG. Here, the damping force by the electromagnetic force can be controlled by the current of the coil 17, and by combining the damping force by the hydraulic damper with the damping force by the electromagnetic force being maximized, the damping force shown by the following can be obtained. Therefore, an arbitrary damping force can be generated in a range between the curves, and by ideally controlling the current of the coil 17, the ideal damping force shown in the following can be obtained.

Next, a third embodiment of the present invention will be described with reference to FIG. Note that the third embodiment has a structure generally similar to that of the second embodiment except that the structure of the hydraulic damper is different. Therefore, the same reference numerals are given to the same parts as those of the second embodiment. Only different portions will be described in detail with reference to FIG.

As shown in FIG. 5, in the electromagnetic suspension device 28 of this embodiment, the hydraulic damper is of a double rod type, and the piston 21 has one end of the piston rod 29 on the side opposite to the piston rod 22. Are connected. The other end of the piston rod 29 is inserted through a rod guide 30 and an oil seal 31 attached to the lower end of the cylinder 20, and extends outside the cylinder 20. Note that the reservoir chamber is omitted.

With this configuration, the second
The same operation and effect as the embodiment can be obtained. In addition, the piston rod 2
Since there is no change in the volume in the cylinder 20 for 2, 29 strokes, no reservoir chamber is required, and miniaturization can be promoted.

Next, an example of a control circuit for controlling the electromagnetic suspension devices of the first to third embodiments will be described with reference to FIG. As shown in FIG. 6, the control circuit 32 includes a switch for switching the energization of the plurality of coils 17.
The CPU 34 determines which coil 17 needs to be energized based on a position detection signal indicating the stroke of the movable bobbin 15, and switches the energized state by the switch 33.

First, a case will be described in which the electromagnetic suspension device is operated as a generator and is controlled by the control circuit 32 as a passive damper having a variable damping force. The switches D, E and F are all turned on, and the passive control signal from the CPU 34 allows the U-phase and V-phase of the coil 17 (three-phase coil)
Switches G and H for turning on / off the short circuit of phase and W
And the duty ratio of I. This allows the coil
By adjusting the magnitude of the current flowing through 17, the damping force can be controlled.

For example, if the ratio of the on time to the off time of the switches G, H, and I is 0: 100 (duty ratio 100), the coil 17 is short-circuited, and the damping force of the electromagnetic suspension device becomes maximum. If the ratio of the on time to the off time is 100: 0 (duty ratio 0), the circuit is opened and the damping force of the electromagnetic suspension device is minimized. Therefore, the damping force can be arbitrarily adjusted by controlling the duty ratio between 100 and 0.

Next, a case will be described in which the electromagnetic suspension device is operated as an actuator and controlled by the control circuit 32 as an active suspension or the like for controlling the attitude of the vehicle body. The switches G, H, and I are all turned on, the voltage from the power supply 35 such as a battery is boosted by a DC / DC converter, and the switches A, B, C, D, E, and F are arbitrarily set by an active control signal from the CPU 34. On / off at a duty ratio of
Generate three-phase drive signals for the phase, V phase, and W phase. Thus, the electromagnetic suspension device can be operated as an actuator to control the thrust.

As a result, control forces (damping force and thrust) for controlling the vibration and posture of the vehicle body are calculated based on, for example, the acceleration of the vehicle body and wheels, the stroke of the electromagnetic suspension device, the yaw rate of the vehicle body, and the like. Optimal control of vehicle conditions by controlling the electromagnetic suspension device
(Active suspension control and active damper control).

[0041]

As described in detail above, according to the electromagnetic suspension device of the first aspect, since the movable bobbin is supported by the large-diameter outer yoke, the bending rigidity can be increased. Further, since the coil is arranged outside the permanent magnet, the diameter of the coil can be easily increased, the electromagnetic force can be increased, and the cooling of the coil can be promoted.

According to the electromagnetic suspension device of the second aspect, in addition to the electromagnetic force of the coil and the permanent magnet, a damping force due to the flow of the oil liquid can be generated, so that the load on the coil and the permanent magnet can be reduced. In addition, the size of the electromagnetic suspension device can be reduced. Further, even when the damping force due to the electromagnetic force is excessively reduced due to the disconnection of the coil or the like, the damping force can be maintained.

According to the electromagnetic suspension device of the third aspect, the damping force or thrust of the movable bobbin can be controlled by controlling the current flowing through the coil.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a schematic configuration of an electromagnetic suspension device according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of the apparatus of FIG.

FIG. 3 is an explanatory diagram showing a magnetic circuit of the device of FIG. 1;

FIG. 4 is a longitudinal sectional view illustrating a schematic configuration of an electromagnetic suspension device according to a second embodiment of the present invention.

FIG. 5 is a longitudinal sectional view illustrating a schematic configuration of an electromagnetic suspension device according to a third embodiment of the present invention.

FIG. 6 is a diagram showing a control circuit for controlling the electromagnetic suspension device of the present invention.

FIG. 7 is a diagram showing damping force characteristics of the electromagnetic suspension device of the present invention.

FIG. 8 is a longitudinal sectional view showing a schematic configuration of a conventional electromagnetic suspension device.

[Explanation of symbols]

 11, 19, 28 Electromagnetic suspension device 12 Outer yoke 13 Center yoke 15 Movable bobbin 17 Coil 18 Permanent magnet 20 Cylinder 21 Piston 22, 29 Piston rod 27 Oil path (damping force generating means)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16F 15/02 F16F 9/32 NHF term (Reference) 3D001 AA02 BA00 DA03 DA17 EB32 3J048 AA10 AB07 AB08 AB11 AC08 AD05 BE03 BE09 CB21 DA01 EA15 EA38 3J069 AA54 BB10 CC09 CC15 DD29 DD40 EE03

Claims (3)

[Claims] 1. A cylindrical outer yoke, a center yoke integrally erected within the outer yoke along its axial direction, and a cylindrical yoke slidably supported inside the outer yoke. An electromagnetic device comprising: a movable bobbin; a coil fixed to an inner peripheral portion of the movable bobbin; and a permanent magnet disposed to face the inner peripheral portion of the coil and fixed to the center yoke. Suspension device. 2. A cylinder formed in the center yoke and filled with an oil liquid, a piston slidably fitted in the cylinder, and connected to the piston and external to the cylinder. A piston rod extending to the movable bobbin and damping force generating means for controlling a flow of an oil liquid generated by sliding of the piston to generate a damping force. 2. The electromagnetic suspension device according to 1. 3. A thrust or damping force is generated on the movable bobbin by controlling a current flowing through the coil to control an electromagnetic force acting between the coil and the permanent magnet. The electromagnetic suspension device according to claim 1 or 2, wherein: