JP3016260B2 - Electromagnetic suspension device - Google Patents

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.

[0002]

2. Description of the Related Art Conventionally, as an electromagnetic suspension device, for example, an electromagnetic suspension device described in Japanese Patent Application Laid-Open No. 2-37016 is known.

[0003] In this conventional apparatus, an outer cylinder formed in a cylindrical shape and fixed to the vehicle body is provided between a vehicle body and a wheel, and is slidably provided in the outer cylinder and attached to the wheel side. A suspension unit having a rod is provided,
In the outer cylinder, a permanent magnet is fixed to the outer periphery of the rod, and a coil is fixed to the inner peripheral side of the outer cylinder facing the permanent magnet.

[0004] By controlling the direction of current supply to the coil and the current, a driving force is generated in the axial direction of the coil of the suspension unit, for example, control is performed to keep the vehicle height constant.

[0005]

However, such a conventional electromagnetic suspension device, as described above,
Because the suspension is controlled by the driving force in the axial direction of the coil, the shock absorbing capacity is limited only by the driving force of the coil, and it is not possible to absorb the large shock input generated depending on the running conditions of the vehicle. In addition, there is a problem that the suspension unit itself may be damaged, and all necessary driving force is generated by electric power, so that power consumption becomes excessive and fuel efficiency of the vehicle is deteriorated. .

The present invention has been made in view of the above-mentioned problem, and provides an electromagnetic suspension device which can prevent the suspension unit from being damaged by a large shock input and can reduce power consumption. It is intended to be.

[0007]

According to the present invention, in addition to the electromagnetic actuator, a shock absorber is provided between the vehicle body-side member and the wheel-side member of the suspension unit, and the damper has a damping force characteristic that is changed. The above object is achieved by providing a force changing means.

[0008] That is, in the electromagnetic suspension apparatus of the present invention, and a vehicle body-side member and the wheel-side member interposed the suspension unit is formed to be relatively moved between the vehicle body and wheels, the vehicle body-side member and the wheel Between the side members
A cylinder tube provided on one of the members,
Is provided on the other side of the material to define the inside of the cylinder tube
A piston rod having a movable piston,
Hydraulic relief that generates damping force with piston stroke
衝器is provided, the liquid pressure shock absorber is changeable damping force changing means the damping force characteristics provided we are in, the vehicle body-side member and the wheel
On one side with the side member, a cylindrical gap suspends its axial direction.
Extending in the stroke direction of the
And a magnetic field that creates a radial magnetic field in this gap
A road is formed, and the other of the vehicle body side member and the wheel side member
Is inserted into the gap, and the magnetic field and the
And the coil is wound in a direction perpendicular to the stroke direction.
It was a means you are.

[0009]

[Work] When the vehicle body-side member and the wheel-side member of the suspension unit relatively move, a damping force is generated in the shock absorber in the same direction as the speed direction of the relative movement. Therefore, when a control force is required in the same direction as the direction of the relative movement speed, the required control force can be obtained by controlling the damping force of the shock absorber, and the control force can be obtained by controlling the damping force of the shock absorber. When an uncontrollable control force is required, the shortage of the control force can be compensated by driving the electromagnetic actuator to generate the electromagnetic force. As described above, since the control force is not obtained only by the electromagnetic force of the electromagnetic actuator, the power consumption of the electromagnetic actuator can be reduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is an overall view showing the structure of an electromagnetic suspension device according to an embodiment of the present invention. In FIG. ing. The suspension unit S has a vehicle body-side member 1 connected to the vehicle body, and a wheel-side member 2 connected to the wheel side.

The vehicle body side member 1 includes an inner cylinder 1 as shown in FIG.
a and the outer cylinder 1b are formed into an inner / outer double cylindrical structure having a cylindrical gap 1c between them. That is, the inner cylinder 1a has a large-diameter cylinder portion 1d formed on an upper portion thereof.
b is provided in the outer cylinder 1b by fitting to the inner surface of the outer cylinder 1b.

The upper end opening of the outer cylinder 1b is closed by a canopy member 1f screwed to the inner peripheral side thereof. The canopy member 1f is formed by a cylindrical portion 1p and a canopy portion 1r screwed to the inner periphery of the outer cylinder 1b.
At the center of the upper surface of r, a stud 1e for attachment to the vehicle body side is formed so as to protrude. An annular groove 1s is formed on the upper surface of the canopy portion 1r.
The annular receiving surfaces 1t and 1u are formed heavily, and the load sensor 9 is provided on the two annular receiving surfaces 1t and 1u. That is, the load sensor 9 is formed by a sensor body 9a and a strain gauge 9b formed in a substantially annular shape by a plate material, and an inner peripheral portion and an outer peripheral portion of the sensor body 9a are connected to the both annular receiving surfaces 1t and 1u. The sensor is provided with the inner peripheral portion sandwiched between the inner annular receiving surface 1t and the washer 1v, and the amount of bending of the sensor body 9a based on the bending of the canopy portion 1r is detected by the strain gauge 9b. Thus, the load input to the suspension unit S can be detected. A step motor 14 is accommodated in the hollow portion of the canopy member 1f, and a harness 14a of the step motor 14 is led out through the center hole 1w of the stud 1e and connected to a control circuit 6 described later. Have been.

At the lower ends of the inner cylinder 1a and the outer cylinder 1b,
A magnetic inner cylinder portion 12 and a magnetic outer cylinder portion 11 made of a ferromagnetic material are respectively mounted. In addition, among the members constituting the vehicle body side member 1, the magnetic inner cylinder portion 12 and the magnetic outer cylinder portion 1 are provided.
The members other than 1 are formed of a non-magnetic material. The inner peripheral surface of the magnetic outer cylinder 11 has a predetermined interval H at the center.
While holding the upper outer permanent magnet 1j and the lower outer permanent magnet 1
k and the inner peripheral surface of the magnetic inner cylinder portion 12, the upper inner permanent magnet 1m and the lower inner permanent magnet 1n are provided on the inner peripheral surface of the magnetic inner cylinder portion 12 while maintaining a predetermined interval H at the center, thereby forming the upper outer permanent magnet 1j An upper magnetic field forming portion 1g and a lower magnetic field forming portion 1h in which the gap of the gap 1c is narrowed are formed between the upper inner permanent magnet 1m and the lower outer permanent magnet 1k and the lower inner permanent magnet 1n. Then, each of the permanent magnets 1
j, 1k, 1m, and 1n form magnetic paths A indicated by alternate long and short dash lines in the figure, and in the upper and lower magnetic field forming portions 1g and 1h, apply magnetic fields B ₁ and B _{2 in} which magnetic flux flies in the radial direction through the gap 1c. The polarities are set so as to form them, that is, in this embodiment, the upper outer permanent magnet 1j and the upper inner permanent magnet 1m
Is an N pole on the inner circumference side, and the lower outer permanent magnet 1k and the lower inner permanent magnet 1n are set to the inner circumference S pole. A guide member 13 having a center hole 13a is screwed and integrated with the lower end of the magnetic inner cylindrical portion 12.

On the other hand, the wheel-side member 2 is formed in a bottomed cylindrical shape having a bottom at a lower end, and a lower end of the piston rod 20 is fixed to the bottom, and a lower spring seat is provided at a lower end of the bottom. 23 and mounting eye 2 for wheel side
a is provided. A suspension spring 33 is interposed between the upper spring seat member 19 and the lower spring seat member 23. The wheel-side member 2 is inserted into the gap 1c from the opening end, and the coil 3 is wound around the outer periphery of the wheel-side member 2 with a small gap with respect to the vehicle-body-side member 1.

The coil 3 is divided into ten first to tenth coils 3a to 3j along the direction of relative movement of the two members 1 and 2, and each coil 3a to 3j is
k. The length of the portion of each bobbin 3k where the coils 3a to 3j are wound is formed between the upper outer permanent magnet 1j (upper inner permanent magnet 1m) and the lower outer permanent magnet 1k (lower inner permanent magnet 1n). It is formed shorter than the set interval H. Note that dry bearings 4a and 4b are provided on the outer periphery of the tip end of the wheel side member 2 and the outer periphery of the guide member 13.

The coil 3 is connected to a control circuit 6. That is, the control circuit 6 is formed so as to be able to conduct current between the terminals of the coils 3a to 3j and to short-circuit the terminals. It is configured to connect. Incidentally, when the coil 3 is short-circuited, when the suspension unit S strokes, the coil 3 moves in a direction crossing the magnetic fields B ₁ , B ₂ of the two magnetic field forming portions 1g, 1h, so that the relative speed to the coil 3 is increased. Is generated, and the induced current consumes power by the variable resistor, so that the moving energy is reduced, that is, a damping force is obtained. On the other hand, when the coil 3 is energized and driven,
When a current is applied across the magnetic fields B ₁ and B ₂ of the two magnetic field forming units 1 g and 1 h, a driving force is generated in the extension direction or the pressure direction of the suspension unit S according to the direction of the current supply. That is, as shown in FIG. 5, a control force proportional to the value of the supplied current is obtained. Thus, in this embodiment, the coil 3 and each of the permanent magnets 1j, 1k, 1m, 1
n and the like form the electromagnetic actuator T.

The control circuit 6 individually turns on and off the energization of each of the coils 3a to 3j in accordance with the stroke position of the suspension unit S based on the input signal from the stroke sensor 7, and controls the energization direction. Is provided. That is, the energization switching means 6a controls so that only the coils existing in the _two magnetic fields B ₁ and B ₂ are energized, and the directions in which the magnetic flux flies in the two magnetic fields B ₁ and B ₂ are opposite to each other. Therefore, in order to make the acting directions of the driving forces generated in the two magnetic field forming portions 1g and 1h coincide, each coil 3a
Of ～3J, upper magnetic field forming unit coils 3a as energizing direction of the coil in a magnetic field B ₂ of the coil and the lower magnetic field forming unit 1h in a magnetic field B ₁ is made in the opposite directions of 1g
To 3j, and switching control of the energizing direction to each of the coils 3a to 3j is performed according to the stroke position of the suspension unit S. still,
The stroke sensor 7 comprises a Hall element (not shown) mounted at the center of each bobbin 3k, and this Hall element changes its output voltage in response to the magnetic fluxes of the magnetic fields B ₁ and B ₂ . By detecting this output voltage, each coil 3a for the magnetic field forming portions 1g and 1h
3j, that is, the stroke position of the suspension unit S is detected.

A hydraulic buffer P is provided in the inner cylinder 1a. That is, a cylinder tube 15 is provided at the axial center of the inner cylinder 1a, and an outer chamber C is formed between the cylinder tube 15 and the inner cylinder 1a on the outer periphery of the inner cylinder 1a to form an outer tube. 16 are provided,
The upper and lower ends of the tubes 15 and 16 are fitted and fixed to the damping force variable valve 18 provided in the large-diameter cylindrical portion 1d and the rod guide 10 formed at the lower end of the inner cylinder 1a. And both tubes 15,
The inside of 16 is filled with a fluid such as oil. The cylinder tube 15 is provided inside the cylinder tube 15.
A piston 17 is slidably defined by defining an upper chamber A and a lower chamber B, and a variable damping force valve 18 and an outer tube are provided in an inner cylinder 1a including the large-diameter cylinder 1d. 16 a desired amount of fluid is formed a main reservoir chamber D ₁ filled under pressure by the gas sealed therein with defined in. The rod guide 10 is provided with a lower communication passage 10b for communicating between the lower chamber B and the outer chamber C.

The piston 17 is mounted on the rod guide 1
It is attached to the upper end of a piston rod 20 inserted into the cylinder tube 15 from the rod insertion hole 10a. Note that a guide bush 21 and an oil seal 22 are provided in the rod insertion hole 10a in contact with the outer peripheral surface of the piston rod 20. An upper spring seat member 1 is provided on an outer peripheral portion of an upper end of the outer cylinder 1b.
9 are provided. The upper spring seat member 19, an annular seat surface 19a is formed on the lower surface periphery, it is an annular groove 19b is formed on the inner peripheral surface side of a position consistent with the main reservoir chamber D _1, the annular A sub-reservoir chamber D filled with a desired amount of fluid under the pressure of the sealed gas between the groove 19b and the outer peripheral surface of the outer cylinder 1b.
₂ are formed. Then, between the and the Saburizaba chamber D ₂ main reservoir chamber D ₁ is the outer cylinder 1b and the communication holes 1x bored in the large-diameter cylindrical portion 1d, which enables mutual fluid communication through 1y.

Next, the structure of the variable damping force valve 18 will be described in detail with reference to FIG.

As shown, the damping force variable valve 18 is
A _first communication passage E that communicates the upper chamber A with the main reservoir chamber D1, a second communication passage F that communicates with the middle of the first communication passage E and the outside chamber C, and a first communication passage with the valve body 18a. Passage E
A first bypass passage G which communicates the main reservoir chamber D ₁ upper chamber A, bypassing the middle and a second bypass passage K for communicating the middle of the first communication passage E in the first bypass passage G
When the first check passage M that communicates the main reservoir chamber D ₁ to the upper chamber A, the main reservoir chamber D ₁ second communication passage F
And a second check flow path N communicating therewith is formed. The first communication passage E has a first damping valve 2
4 and a second damping valve 25 are provided, and an adjuster (damping force changing means) 28 forming the first orifice 26 and the second orifice 27 is provided in the middle of the first bypass path G and the second bypass path K. The first check flow path M is provided with a first check valve 29,
A second check valve 30 is provided in the second check channel N.

The valve body 18a is fastened to a lower end of a support pipe 31 by a nut 31, and an upper end of the support pipe 31 is connected and fixed to a casing of the step motor 14. And the adjuster 28
Is rotatably provided in a through hole 31a of the support pipe 31, is connected to an output shaft of the step motor 14 via a control rod 28a, and is rotated by the adjuster 28 based on driving of the step motor 14. The opening degree of the first orifice 26 and the second orifice 27 is configured to be variable.

The control circuit 6 includes an acceleration sensor 8
And the step motor 14 is controlled based on the input from the stroke sensor 7 and the load sensor 9. Incidentally, the acceleration sensor 8 is attached to the vehicle body to detect the vertical acceleration of the vehicle body, and is provided for obtaining the vehicle speed in the vertical direction. Further, the load sensor 9 detects an input load from the suspension unit S in order to obtain a relative speed between the vehicle body side and the wheel side.

Next, the operation of the embodiment will be described.

In the electromagnetic suspension device having the above-described structure, the suspension unit S is provided between each of the four wheels of the automobile and the vehicle body. The control circuit 6 and the sensors 7, 8, 9 are also provided for each suspension unit S. Is used.

First, the operation of the hydraulic buffer P will be described with reference to the circuit diagram shown in FIG.

In the pressure side process, the upper chamber A is reduced and the lower chamber B is expanded. Therefore, in this case, the fluid in the upper chamber A, but flows to the lower chamber B and the main reservoir chamber D _1,
In this case, there are the following three routes that can be distributed.

The path that flows into the main reservoir chamber D ₁ and the first bypass passage G through the first orifice 26 as.

After passing through the first communication passage E, passing through the first damping valve 24, flows into the outer chamber C via the second communication passage F, and further flows from the outer chamber C through the lower communication passage 10b to the lower chamber B.
The route that flows into.

After passing through the first bypass path G, from there,
A path bypassing the second bypass path K, passing through the second orifice 27, and flowing into the outer chamber C and the lower chamber B via the second communication path F in the same manner as the path.

Accordingly, a damping force is generated in the first damping valve 24 or both orifices 26 and 27. The flow of the above-mentioned respective paths differs depending on the opening degree of both orifices 26 and 27 and the characteristics of the first damping valve 24. However, when the opening degree of both orifices 26 and 27 is opened, the low damping is achieved. It becomes a force characteristic and becomes a high damping force characteristic when closed, and the damping force characteristic is shown in FIG.

During the extension stroke, the lower chamber B is reduced and the upper chamber A is expanded. In this case, the fluid in the lower chamber B flows through the outer chamber C to the upper chamber A or the main reservoir chamber D _1.
With flows to, those fluid in the main reservoir chamber D ₁ flows into the upper chamber A, allows flow paths of the fluid in this case, the following three-fold.

The route outer chamber and C flows from the lower chamber B, from which, through the second communication passage F, and the first communication passage E, flows into the main reservoir chamber D ₁ by opening the second damping valve 25.

In the same manner as described above, the vehicle passes through the second communication path F,
From there, a path that passes through the second bypass path K to the first bypass path G and flows into the upper chamber A.

A path that flows from the main reservoir chamber D ₁ to the upper chamber A via the first check channel M.

Therefore, the second damping valve 25 or the second damping valve 25
A damping force is generated at the orifice 27. Also in this case, the flow path changes depending on the opening degree of the second orifice 27 and the characteristics of the second damping valve 25, and the damping force characteristics also change as shown in FIG.

Next, the operation of the electromagnetic actuator T will be described.

In order to generate a damping force in the electromagnetic actuator T according to the running condition of the vehicle, each coil 3
a to 3j are short-circuited. Then, a damping force (control force) is generated according to the relative speed between the vehicle body-side member 1 and the wheel-side member 2, that is, in direct proportion to the speed of the coil 3 passing through the upper and lower magnetic field forming portions 1g, 1h. As described above, when performing the damping force control, the coil 3 is not energized, that is, the damping force (control force) can be obtained without consuming any power.

When a driving force is generated in the electromagnetic actuator T such as for controlling the attitude, the coil 3 is energized in accordance with the vehicle conditions obtained based on the inputs from the sensors 7 to 9. As a result, a driving force (control force) is generated upward or downward in the axial direction of the suspension unit S. In this case, the direction and strength of the driving force (control force) change depending on the direction of power supply and the power. Incidentally, such a driving force (control force) is generated, for example, in such a direction as to cancel a change in the vehicle height, whereby the vehicle height can be kept constant. Further, by generating the driving force (control force) in a direction to cancel the road surface input transmitted to the vehicle body via the suspension unit S, the road surface input to the vehicle body is canceled and a constant vehicle body posture is obtained.

FIG. 6 shows an example of controlling the control force (driving force / damping force) of the apparatus according to the embodiment of the present invention. The required control force characteristics are shown, and the hatched lines indicate the control force (damping force) F _{D that} can be generated by the hydraulic buffer P.
It is. That is, assuming that the proportionality constant is a and the sprung speed is v _u , a large control force (F _S = a · v) is required to achieve suspension control equivalent to an ideal skyhook damper.
requires a _u), the spring - in the area where the direction between the unsprung relative speed coincides with the direction of the suspension control force F _S, the control force of the hydraulic shock absorber P (damping force) F _D is to work , The control force F _G required to be generated at the electromagnetic actuator
Is F _G = F _S −F _D , thus saving power consumption.

Incidentally, the skyhook theory is a theory in which, in the vibration model shown in FIG. 7, a control force F _S having a relationship represented by the following equation 1 is generated for the sprung speed V ₁ to control only sprung vibration. It is. Note that M is mass, K is spring constant, C is damping coefficient, and V ₁ is sprung speed.

[0042]

(Equation 1)

As described above, in the apparatus of the present invention, the electromagnetic actuator T is provided with the hydraulic buffer P in parallel, so that the suspension unit can be prevented from being damaged by a large shock input. In addition, it has a feature that the power consumption of the electromagnetic actuator T can be reduced.

Further, in performing the damping force control and the posture control, in the apparatus of the present invention, the gap 1c is formed, and the magnetic outer cylinder 11 and the magnetic cylinder 12 facing each other are moved relative to each other. Two magnets (an upper outer permanent magnet 1j, a lower outer permanent magnet 1, and an upper inner permanent magnet) which are separated in the same direction and oppose each other to form magnetic fields B ₁ and B ₂ in opposite directions with the gap 1c interposed therebetween. 1m, lower inner permanent magnet 1
n), a magnetic path A for forming _two magnetic fields B ₁ and B ₂ is formed, and the direction of energization of each of the plurality of divided coils 3a to 3j is crossed by one of the magnetic fields B _1. and because of the other coil which intersects the magnetic field B ₂ in a configuration in which a control circuit 6 for switching to be opposite to each other, there is no need to lengthen the path a, even if increasing the stroke of the suspension unit S Therefore, it is characterized in that a constant and sufficient control force can be obtained regardless of the magnitude of the stroke.

In this embodiment, the power consumption is controlled by controlling only the coil portion necessary for generating the control force (driving force) in each of the 10 divided coils 3a to 3j. Has the feature of being able to save money.

Further, in the apparatus of the present invention, a magnetic flux sensor such as a Hall element is used as the stroke sensor 7 for detecting the stroke position of the suspension unit S, so that the suspension can be extended without increasing the basic length of the suspension. The stroke position of the unit S can be detected, which has a feature that the degree of freedom in space when mounted on a vehicle is increased.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific structure of the present invention is not limited to these embodiments. For example, in the embodiment, the example in which the vehicle body-side member is formed in a double structure is described. . Further, in the embodiment, the case where the magnetic path is formed between the two upper and lower magnetic field forming units has been described.
A magnetic path may be formed by one set of the magnetic field forming portion and the magnetic member. Further, in the embodiment, the magnetic field is formed by the permanent magnet, but the magnetic field may be formed by the electromagnet. Further, in the embodiment, both magnets and coils for forming a magnetic field are formed in a ring shape, and both are arranged concentrically. However, the shapes and arrangement relationship of both magnets and coils can be arbitrarily set. Further, by changing the number of turns of each coil depending on the stroke position, the control force can be arbitrarily changed depending on the stroke position.

[0048]

As described above, in the electromagnetic suspension device of the present invention, a shock absorber is provided between the vehicle body-side member and the wheel-side member of the suspension unit in addition to the electromagnetic actuator. Since the damping force changing means for changing the damping force characteristics is provided, the effect of preventing the suspension unit itself from being damaged by a large shock input due to the shock absorbing action of the shock absorber is obtained, and the electromagnetic actuator is provided with the damping force of the shock absorber. By driving the electromagnetic actuator only when a control force that cannot be controlled by force is required, the power consumption of the electromagnetic actuator can be saved.

[Brief description of the drawings]

FIG. 1 is an overall view showing an electromagnetic suspension device according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a damping force variable valve portion of the device according to the embodiment of the present invention.

FIG. 3 is a circuit diagram of a hydraulic buffer in the apparatus according to the embodiment of the present invention.

FIG. 4 is a damping force characteristic diagram of a hydraulic shock absorber in the device according to the embodiment of the present invention.

FIG. 5 is a control force characteristic diagram of an electromagnetic actuator in the device according to the embodiment of the present invention.

FIG. 6 is a control force characteristic diagram when the apparatus of the present invention is controlled as a skyhook damper.

FIG. 7 is an explanatory diagram for explaining the skyhook theory.

[Explanation of symbols]

 S Suspension unit P Hydraulic shock absorber T Electromagnetic actuator 1 Body side member 2 Wheel side member 28 Adjuster (damping force changing means)

Claims (1)

(57) [Claims] A suspension unit interposed between a vehicle body and a wheel includes a vehicle body-side member and a wheel-side member formed to be relatively movable, and a suspension unit is provided between the vehicle body-side member and the wheel-side member. On one of the members
The cylinder tube provided and the other of the two members
Slidable piston that defines the inside of the cylinder tube
And a piston rod having a ton.
There is a hydraulic shock absorber that generates damping force with the troke.
Is, liquid pressure shock absorber is changeable damping force changing means the damping force characteristics provided we are in, in one of said vehicle body side member and the wheel-side member, a cylindrical gap
Is the direction of the stroke of the suspension unit.
In the direction of
A magnetic path for forming a magnetic field in the opposite direction is formed, and the other of the vehicle body-side member and the wheel-side member is inserted into the gap.
The magnetic field and the stroke
An electromagnetic suspension device , wherein a coil is wound in a direction perpendicular to the direction .