JPH04197813A - Electromagnetic suspension unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an electromagnetic suspension device.

(Prior Art) Conventionally, as an electromagnetic suspension device, one described in, for example, Japanese Utility Model Application Publication No. 1-116710 is known.

This conventional suspension system has a cover formed in a cylindrical shape and fixed to the vehicle body between the vehicle body and the wheels, and a piston that is slidably provided inside the cover and attached to the wheel side. A unit is provided, a fixed coil and a control coil are provided in the cover, a fixed coil is provided in the piston, and an outer surface of the cover includes:
The structure includes a position sensor that detects the relative position of the piston to the fixed coil.

Based on the detection signal from the position sensor, by controlling the direction of energization and current to each coil, a control force (attraction/repulsion force) is generated in the axial direction of the coil, for example, to maintain a constant vehicle height. control to maintain the temperature.

(Problem to be Solved by the Invention) However, as described above, in such conventional electromagnetic suspension devices, the suspension was controlled by the control force generated in the axial direction of the electromagnetic coil, so the suspension unit When the distance between the electromagnetic coils changes, the attraction/repulsion between the coils changes accordingly, making accurate control difficult.

Additionally, when the suspension unit strokes, the distance between the piston-side coil and the position sensor changes, so the output characteristics of the position sensor with respect to the coil displacement become non-linear, making it difficult to obtain accurate relative velocity values. Moreover, when the stroke becomes large, the output gain decreases, making it difficult to detect the relative speed.

Furthermore, the electromagnetic coil must always be energized while the control force is being generated, resulting in a problem of extremely large power consumption.

The present invention has been made with attention to the above-mentioned problem, and it is possible to obtain a constant strong control force even when the suspension unit strokes, and to achieve excellent controllability and reduce power consumption. It is an object of the present invention to provide an electromagnetic suspension device which is capable of detecting relative speed even when the stroke is large, and which can obtain linear output characteristics in this case.

(Means for Solving the Problems) In order to achieve the above-mentioned object, in the present invention, a magnetic field forming part that forms a magnetic field in the radial direction is formed on one of the vehicle body side member and the wheel side member, and inside this magnetic field forming part. At the same time as placing the other member on this part, a driving coil is wound around this part, and further,
A speed detection coil was provided in the middle of this drive coil.

That is, in the electromagnetic suspension device of the present invention, the suspension unit interposed between the vehicle body and the wheels is formed of a vehicle body side member and a wheel side member that are formed to be relatively movable in the axial direction, and the vehicle body side member A magnetic field forming portion for forming a magnetic field in a radial direction orthogonal to the axial direction is formed on one of the vehicle body side member and the wheel side member, and a magnetic field forming portion of the other member of the vehicle body side member and the wheel side member is formed. A drive coil is wound in a direction that intersects the relative displacement direction and the magnetic field direction, and a speed sensor is similarly wound in the middle part of the drive coil in a direction that intersects the relative displacement direction and the magnetic field direction. This is the means by which the coil is wound.

(Function) In the electromagnetic suspension device of the present invention, when the drive coil is energized, it is energized in a direction that intersects the stroke direction of the suspension unit and the magnetic field direction.
A driving force is generated in a direction that intersects both the direction of the magnetic field and the energization direction, that is, the stroke direction of the suspension unit.

Therefore, this driving force causes the suspension unit to expand or shorten.

Therefore, this driving force can be applied to resist the input to the suspension unit, thereby suppressing the stroke of the suspension unit due to external input.

Furthermore, when the suspension unit strokes, the speed detection coil relatively moves in a direction across the magnetic field within the magnetic field forming section, thereby generating an induced electromotive force in the speed detection coil that is linearly proportional to the relative speed.

Therefore, by measuring this induced electromotive force, the relative speed can be detected, and the suspension unit can be controlled based on this detected value.

On the other hand, when the drive coil is not energized, when the suspension unit is stroked by external input, the drive coil moves relatively within the magnetic field, and an induced current is generated in the drive coil in proportion to the relative speed.

Therefore, when this induced current is consumed by the coil resistance or external resistance, the input energy to the suspension unit is consumed and damping is achieved.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

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

In this figure, S indicates a suspension unit. This suspension unit S includes a vehicle body side member 1 connected to the vehicle body side and a wheel side member 2 connected to the wheel side.

The vehicle body side member 1 is made of a magnetic material, and has a cylindrical inner column 1a and a bottomed cylindrical outer tube 1b provided at the axial center as shown in the figure, with a gap 1C between them. It is formed into a double structure. The inner column 1a is integrally formed with the outer tube 1b by fastening the tip of the rod portion 1d to a bolt member 1e with a rod portion 1d formed at the upper part passing through the bottom of the outer tube 1b. .

Further, in the vehicle body side member 1, the lower path half of the outer cylinder 1b is bulged inward, and the outer permanent magnet 1 is attached along the inner circumferential surface of the bulged portion.
j, and by bulging the lower half of the inner column 1a outward and providing the inner permanent magnet 1k along the outer peripheral surface of the bulging portion, a magnetic field is formed by narrowing the interval between the gaps 1c. A portion 19 is formed.

Further, as shown in FIG. 3, both the permanent magnets 1j and lk are each divided into four in the circumferential direction, and the magnetic field direction thereof is in the radial direction across the circumferential gap 1c. , the poles and direction of both permanent magnets 1j and Ik are set. In this embodiment, the inner circumferential side is set to be the S pole.

A cylindrical reinforcing permanent magnet 1f is provided on the outer periphery of the rod portion 1d, and is fixed by the fastening force between the rod portion 1d and the bolt member 1e. Note that the bolt member 1e is for attaching to the main body.

That is, since this heavy body side member 1 is formed of a magnetic material, both the permanent magnets 1j, 1k and the reinforcing permanent magnet 1
f, a magnetic path A shown by a dashed line in the figure is formed, and in this magnetic field forming portion 19, a magnetic field B is formed in the radial direction as shown in FIG. In addition, the direction of magnetic path A is
It differs depending on the polarity direction of each permanent magnet 1j, lk, if.

Further, a reinforcing drive coil 1h is wound around the outer periphery of the inner column 1a at a position between the magnetic field forming part 19 and the reinforcing permanent magnet 1f.

On the other hand, the wheel side member 2 is formed into a bottomed cylindrical shape having a bottom at the lower end, and a port 2a for attachment to the wheel side is provided upright at the lower end. The wheel side member 2 is inserted into the gap 1C through its open end, and the drive coil 3 has a slight gap on its outer periphery with respect to the vehicle body side member 1.
is wrapped around it. The drive coil 3 is formed of independent first to eighth drive coils 38 to 3h.

The fourth drive coil 3d and the fifth drive coil 3e
A speed detection coil 7c is wound between. Note that each drive coil 3a to 3h and 5 is wound around one bobbin 3k.

In addition, the overwhelming stroke range of the suspension unit S is S1%, the stroke range on the extension side is 82, the range where the speed detection coil IC can move to the compression side is 7, and the range where the speed detection coil 7c can move to the extension side. Letting D2 be, the length of the magnetic field forming portion 19 is set so that the relationship between the respective lengths is S I <DI S2 <D2.

That is, in the stroke range of the suspension unit S, the speed detection drive coil 7c is always placed in the magnetic field B.

Further, bearings 4a, 4b, and 4c are provided between the wheel side member 2, the inner column 1a, and the outer cylinder 1b.

The drive coil 3, the speed detection coil 7c, and the reinforcing drive coil 1h are connected to a control circuit 6. That is,
The control circuit 6 energizes the reinforcing drive coil 1h so that a magnetic field is generated in the same direction as the magnetic field formed in the vehicle body side member 1.

The control circuit 6 also switches the connection state of each of the drive coils 38 to 3h to the drive coil 3 by connecting them in series as shown in FIG. 4 or in parallel as shown in FIG. Each drive coil 3a~
The drive coil 3 is configured to be able to conduct current or short-circuit between the terminals of 3h, and is further configured to connect a variable resistor to these drive coils 3 during this current conduction and short-circuit.

FIG. 6 is a circuit diagram showing the configuration of the control circuit 6, in which the first drive coil 3a and the second drive coil 3b
Only the parts that control the are shown.

This control circuit 6 includes a variable resistor 6a, and applies signals of 0 and 1 to the terminals ■, ■, ◎, and ■, respectively, in the combinations shown in Figure 1, to control the first drive coil 3.
A and the second drive coil 3b are connected in parallel or in series, and both drive coils 3a and 3b are short-circuited or both drive coils 3a and 3b are driven with electricity.

<Chart 1> By the way, when the drive coil 3 is short-circuited, when the suspension unit S strokes, the magnetic field forming part 1
When the drive coil 3 moves in a direction across the magnetic field mill 9, an induced current proportional to the relative speed is generated in the drive coil 3, and this induced current consumes power by the variable resistor 6a, thereby reducing the movement energy. In other words, damping force can be obtained.

On the other hand, when the drive coil 3 is energized and driven, the energization is carried out in a direction that crosses the magnetic field B of the magnetic field forming section 19, so that a driving force is generated in the extension direction of the suspension unit S depending on the direction and strength of the energization. act or a driving force acts on the pressure surface.

Incidentally, the damping force and driving force (hereinafter referred to as control force) generated as described above are larger when the drive coils 3 are connected in parallel than when they are connected in series.

That is, the number of drive coils 38 to 3h that cross the magnetic field forming section 19 is set to 5, and the length of all drive coils 38 to 3h is set to 5! . When closed, the generated force F5 in the case of series connection is expressed by the following 0 formula, while the generated force FP in the case of parallel connection is 0
Expressed by the formula.

That is, B2 (5[)2 ・E・” 8RX 2582L2 ・=1× 8 ・X・・・・・・・・・■82L2 ・Fp=5X-Go・× R/8 82L2 ・=40× R・×・・・・・・・・・■However, B: Magnetic flux density in the magnetic field forming part: Relative speed between the drive coil and the magnetic field: Winding length per drive coil R: Winding length per drive coil It is the resistance value.

Therefore, Fp / Fs = 40/ (25'/ 8) # 1
3, and the parallel connection provides 13 times more control power than the series connection.

Note that the control circuit 6 includes a vehicle height sensor 7a and an acceleration sensor 7b.
Control is performed based on the input from the speed detection drive coil 7c.

The vehicle height sensor 7a is provided between the vehicle body side member 1 and the wheel side member 2 of the suspension unit S, and is configured to be able to detect the vehicle height based on the stroke amount of both.

The acceleration sensor 7b is attached to the vehicle body to detect the vertical acceleration of the vehicle body, and is provided to determine the vehicle speed in the vertical direction.

The speed detection drive coil 7C is provided to determine the relative speed between the vehicle body side and the wheel side.

The calculation section of the control circuit 6 performs control to keep the vehicle posture constant based on the input from the vehicle height sensor 7a, and performs damping force control based on the input signals from the acceleration sensor ab and the speed detection drive coil 7C. It is configured to do so.

This damping force control is performed, for example, as disclosed in Japanese Patent Application No. 1-177792 filed by the applicant of the present application.

Next, the operation of the embodiment will be explained.

In the electromagnetic suspension device having the above-mentioned configuration, the suspension unit S is provided between each of the four wheels of the automobile and the vehicle body, and the control circuit 6, both sensors 7a and 7b, and the speed detection drive coil 7C are also integrated into one suspension. It is provided and used for each unit S.

(a) When controlling damping force When generating damping force in the suspension unit S according to the vehicle running condition, each drive coil 38 to
Short-circuit 3h.

Then, a damping force (control force) is generated in accordance with 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 drive coil 3 passing through the magnetic field forming section 19.

A diagram showing the damping force characteristics at this time is shown in FIG. 7. If the drive coils 3 are connected in parallel as shown in FIG. By arbitrarily selecting the resistance value of the resistor 6a, H in FIG.
The damping force characteristic can be selected within the range of i.

On the other hand, in the case of series connection as shown in Fig. 4, the control force becomes small, and in this case as well, by arbitrarily selecting the resistance value of the variable resistor 6a, the damping force characteristic can be adjusted within the range of Lo shown in Fig. 7. can be selected.

In this way, when performing damping force control, the drive coil 3
In other words, damping force (control force) can be obtained without consuming any electric power.

Note that when the reinforcing drive coil 1h is energized, a decrease in magnetic flux density in this region is prevented, and as a result, the magnetic field B of the magnetic field forming section 19 increases, thereby making it possible to obtain a large damping force (control force). and large damping force (control force)
Power consumption can be saved by turning off the power when it is not needed.

(b) Attitude control When performing attitude control, the drive coil 3 is energized according to the vehicle situation obtained based on the input from each sensor 7az7c, and the driving force ( control force) to perform posture control.

In this case, the direction and strength of the driving force (control force) change depending on the direction of energization and electric power, and the driving force (control force) at this time changes.
Fig. 8 shows the control force characteristics.

At this time as well, the magnitude of the control force differs depending on whether the drive coils 3a to 3h are connected in parallel or in series.
, Hi2 indicates the case of parallel connection, and the variable resistor 6a
By arbitrarily changing the resistance value of Hil, Hi
The driving force (control force) changes within a range of 2. Note that the current direction is reversed between Hil and Hi2.

On the other hand, in the case of series connection, the driving force (control force) changes within the range of Lol and Lo2.

For example, by generating such driving force (control force) in a direction that cancels out changes in vehicle height, the vehicle height can be kept constant. Further, by generating the driving force (control force) in a direction that cancels the road surface input transmitted to the vehicle body via the suspension unit S, the road surface input to the vehicle body can be canceled and a constant vehicle body posture can be obtained.

(c) When the suspension unit S strokes when detecting relative speed, the speed detection coil 7c moves in a direction crossing the magnetic field B of the magnetic field forming section 19.
By moving, an induced electromotive force proportional to the relative speed is generated in the speed detection coil 7c. FIG. 9 shows the output characteristic at this time, which is a linear characteristic that is linearly proportional to the relative speed of the suspension unit S.

Note that the speed detection coil γC is connected to the magnetic field B of the magnetic field forming section 19.
By moving within the range of , the relative velocity can be detected over the entire stroke.

In performing the damping force control and attitude control as explained above, in the apparatus according to the embodiment of the present invention, in the magnetic field forming section 19,
Since a magnetic field mill is formed in the radial direction and the drive coil 3 is configured to move within this magnetic field B, the distance between the magnetic field B and the drive coil 3 is always kept constant even when the suspension unit S strokes. , the generated control force can be kept constant, there is no problem that the control force changes depending on the stroke amount, and the controllability is excellent.

Furthermore, by arranging the inner permanent magnet 1 and the outer permanent magnet 1j in the magnetic field forming section 19, the magnetic field of the magnetic field forming section 19 becomes stronger, and thereby a large control force can be obtained. There is.

In addition, a speed detection coil 7c is provided in the middle part of the drive coil 3.
By arranging and moving the speed detection coil 7c within the range of the magnetic field B of the magnetic field forming part 1g, relative speed can be detected in the entire stroke range, and the speed detection coil A By moving within the magnetic field B of the same strength, a linear output characteristic proportional to the relative speed can be obtained, which is characterized in that controllability can be improved.

Furthermore, in this embodiment, the reinforcing permanent magnet 1f is provided on the inner column 1a, thereby reinforcing the strength of the magnetic field of the magnetic path A formed on the inner column 1a, so that the inner and outer permanent magnets 1j
, 1k, that is, without increasing the outer diameter of the suspension unit S, the strength of the magnetic field can be reinforced.

Further, in the middle of the magnetic field formed by the permanent magnets 1j, lk and the reinforcing permanent magnet 1f, a reinforcing drive coil 1h is provided at a portion where the magnetic field is formed in the axial direction, so that the magnetic field by each permanent magnet 1j, lk, if is Since the current is energized so that a magnetic field is generated in the same direction as the magnetic field, a decrease in magnetic flux density is prevented in this part, and a strong control force can be obtained. It has the feature that power consumption can be saved by canceling it.

Furthermore, by making it possible to connect the drive coils 3 in parallel,
It is possible to obtain a large control force compared to the length of the drive coil 3, resulting in high efficiency, and the inductance is reduced compared to a case where the drive coil 3 has the same overall length in series, improving responsiveness. It has characteristics.

Moreover, when generating a damping force in the suspension unit S, there is no need to apply a drive current to the drive coil 3, and the control force (damping force) can be obtained without consuming electric power. have.

Next, a second embodiment of the present invention shown in FIG. 10 will be described.

This embodiment is different from the first embodiment in which the first to eighth drive coils 3a to 3h are wound around each of a plurality of bobbins, that is, one drive coil is wound around one bobbin. This is an example in which a plurality of drive coils 201, 201, 203 are wound around one bobbin 200.

In this second embodiment, a large current can be passed without changing the total number of turns of the drive coils 201 to 203.
Can generate large output.

Furthermore, since such a large output can be obtained, it is possible to use a drive coil with a small diameter, and therefore, the external dimensions can be reduced and the device can be made more compact.

Moreover, since the drive coil length of each of the drive coils 201 to 203 is shortened, inductance is reduced and responsiveness can be improved.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration of the present invention is not limited to these embodiments.

For example, in the embodiment, an example is shown in which the vehicle body side member is formed into a double structure, but the wheel side member and the vehicle body side of the embodiment device may be reversed to form the wheel side member into a double structure. .

Further, in the embodiment, the magnetic field is mainly formed by permanent magnets in the vehicle body side member, but the magnetic field may be formed by electromagnets. In this case, the electromagnets may be provided to form the magnetic path A of the embodiment.

In addition, in the embodiment, the number of turns of each of the first to eighth drive coils is the same (same resistance value), but by changing the number of turns of each drive coil depending on the stroke position, the control force can be adjusted depending on the stroke position. It can be changed arbitrarily.

(Effects of the Invention) As described above, in the electromagnetic suspension device of the present invention, a magnetic field forming portion is formed in one of the vehicle body side member and the wheel side member, and the drive coil is located at the position of the other magnetic field forming portion of both members. Even if the suspension unit strokes and the vehicle body side member and the wheel side member move relative to each other, the distance between the magnetic field forming part and the drive coil can be kept constant. It is possible to obtain a constant driving force and damping force without being affected by the amount, and the effect of excellent controllability can be obtained.

In addition, when the drive coil is de-energized, it is possible to generate damping force by consuming the induced current generated in the drive coil, making it possible to obtain damping force without consuming any power. Effects can be obtained.

Furthermore, in the present invention, since the speed detection coil is disposed in the middle part of the drive coil, when the suspension unit is stroked, an induced current linearly proportional to the relative speed is generated in the speed detection coil. It is possible to detect the stroke amount, and the detection accuracy can be improved.

[Brief explanation of the drawing]

Fig. 1 is an overall view showing an electromagnetic suspension device according to a first embodiment of the present invention, Fig. 2 is an enlarged sectional view showing main parts of the device according to the first embodiment, and Fig. 3 is a cross section taken along the line ■-■ in Fig. 1. Figures 4 and 5 are circuit diagrams showing the connection of the drive coil, and Figure 6 is the circuit diagram showing the connection of the drive coil.
A circuit diagram showing the main parts of the control circuit of the embodiment device, FIG. 7 is a damping force characteristic diagram of the first embodiment device, FIG. 8 is a driving force characteristic diagram of the first embodiment device, and FIG. 9 is a diagram of the first embodiment device. FIG. 10 is a side view showing the main parts of the device according to the second embodiment of the present invention. S...Suspension unit...Vehicle side member 19...Magnetic field forming section 2...Wheel side member 3...Drive coil 6...Control circuit 7c...Speed detection coil

Claims (1)

[Claims] 1) A suspension unit interposed between a vehicle body and a wheel is formed of a vehicle body side member and a wheel side member that are formed to be relatively movable in an axial direction, and the vehicle body side member and the wheel A magnetic field forming portion that forms a radial magnetic field perpendicular to the axial direction is formed on one side of the side member, and is arranged across the magnetic field forming portion of the other member of the vehicle body side member and the wheel side member. A drive coil is wound in a direction crossing the relative displacement direction and the magnetic field direction, and a speed detection coil is similarly wound in the middle part of the drive coil in a direction crossing the relative displacement direction and the magnetic field direction. An electromagnetic suspension device characterized by being wound with.