JP2002257189A - Electromagnetic suspension unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively cool a coil of an electromagnetic damper in an electromagnetic suspension unit. SOLUTION: Air chambers 24, 26, and 27 are formed by arranging the electromagnetic damper 4 in the inside of an air spring 2. The air chamber 27 has volume elasticity by means of a diaphragm 7. The air chambers 24 and 26 are connected each other through circular clearance 28 and circular passages 29 and 30 adjacent to a coil 18. The air chambers 26 and 27 are also connected each other by a passage 34 having lead valve 34. The air chambers 24 and 27 are connected each other by a passage 31 having a lead valve 32. When the electromagnetic suspension unit 1 is in a stroke, differential pressure is generated between the air chambers 24 and 26 and the air chamber 27 caused by volume elasticity of the air chamber 27, and air is circulated to one direction through the circular clearance 28 and the passages 29, 30, 31, and 33 by means of the lead valves 32 and 34. Consequently, heat of the coil 18 can be diffused to an entire air chamber, and its cooling can be promoted.

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 a vehicle such as an automobile or a railway vehicle, and controls the vibration between a sprung portion and an unsprung portion by an electromagnetic force.

[0002]

2. Description of the Related Art A magnet and a coil are mounted between a sprung portion and a unsprung portion of a vehicle, and a damping force or a propulsive force is generated between the sprung portion and the unsprung portion by controlling an induced current generated in the coil by a relative displacement between the magnet and the coil. Electromagnetic dampers adapted to act are known.

In an electromagnetic damper, the damping force is almost proportional to the magnitude of the current flowing through the coil. Therefore, the damping force can be easily controlled by controlling the current flowing through the coil by means of a variable resistor or on / off duty control of the circuit. The damping force can be adjusted. In this manner, the so-called semi-active control that controls the body posture by controlling the damping force and the stroke of the electromagnetic damper in real time based on parameters representing the running state such as the vehicle speed and acceleration using various sensors and controllers. Damper control can be performed relatively easily. At this time, since it is not necessary to supply power to the electromagnetic damper, power consumption can be reduced.

[0004] In addition, since the propulsion force is obtained by supplying electric power to the coil of the electromagnetic damper, the electromagnetic damper can be operated as an actuator (motor). Active suspension control can also be performed.

[0005] As a prior art relating to an electromagnetic damper, for example, an electromagnetic damper that is combined with a normal hydraulic shock absorber to reduce the load on the electromagnetic damper and reduce the size and weight has been proposed. (See JP-A-4-215510).

Further, an electromagnetic damper and a hydraulic shock absorber are arranged inside the air spring, and the electromagnetic damper is shielded from the outside to prevent foreign matters such as iron powder and moisture from adhering to the magnet and the coil. An electromagnetic suspension device has been proposed (see JP-A-10-47405).

[0007]

However, the electromagnetic suspension device in which the electromagnetic damper is arranged inside the above-mentioned conventional air spring has the following problems. Since the electromagnetic damper is arranged inside the air spring and most of the hydraulic shock absorber is covered by the air spring, the electromagnetic damper and the hydraulic shock absorber cannot be directly cooled by the outside air. Oil temperature tends to rise. As a result, there is a possibility that the temperature of the magnet increases and the magnetic force decreases, or that the viscosity of the oil liquid decreases and the damping force decreases due to the increase in the oil temperature. In addition, in order to prevent overheating of the electromagnetic suspension device, it is necessary to reduce the current flowing through the coil and / or set the damping force of the hydraulic shock absorber to a low level to suppress the generation of heat, which makes it difficult to obtain a large damping force. There is.

[0008] The present invention has been made in view of the above points, and has as its object to provide an electromagnetic suspension device that can efficiently cool the coil of an electromagnetic damper.

[0009]

In order to solve the above-mentioned problems, the invention according to claim 1 controls a current generated in a coil by a relative displacement between a magnet and a coil to generate a damping force or a propulsion force. An electromagnetic suspension device having an electromagnetic damper disposed inside an air spring, wherein a plurality of chambers are formed in the air chamber, and a passage communicating the plurality of chambers is arranged adjacent to the coil. With the stroke, air is circulated in one direction between the plurality of chambers through the passage to cool the coil. With this configuration, heat is exchanged between the air circulating in the passage in one direction and the coil by the stroke of the air spring, so that the heat of the coil can be diffused to the entire air chamber. An electromagnetic suspension device according to a second aspect of the present invention is characterized in that, in the configuration of the first aspect, the passage is provided with a throttle or a check valve. With this configuration, the air flowing through the passage can be reliably circulated in one direction. An electromagnetic suspension device according to a third aspect of the present invention is characterized in that, in the configuration of the first or second aspect, at least one of the plurality of chambers has volume elasticity. With this configuration, a pressure difference is generated between the plurality of chambers due to the volume elasticity, and the air can be circulated by the pressure difference.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 1, an electromagnetic suspension device 1 according to the present embodiment is a suspension device mounted between a vehicle body (spring-up) and a wheel (unsprung) of a vehicle, and includes a spring element that supports the vehicle body. , An air spring 2, and a hydraulic shock absorber 3 and an electromagnetic damper 4 as shock absorbing elements.
And

The air spring 2 is formed by connecting a large-diameter, substantially bottomed cylindrical upper case 5 and a small-diameter, substantially bottomed cylindrical lower case 6 by a diaphragm 7 formed by folding an elastic cylindrical member. , And an air chamber is formed therein. The upper case 5 has a supply / discharge device including a pressurized air source and a supply / discharge control valve via an electromagnetic on-off valve 8.
(Not shown) is connected. The air spring 2 has an upper case 5 connected to a vehicle body side (not shown) via an upper mount 9, and a lower case 6 serving as a cylinder of a hydraulic shock absorber 3 described later.
It is connected to the wheel side (not shown) via 10.

In the hydraulic shock absorber 3, a piston (not shown) having a piston rod 11 connected thereto is slidably fitted in a cylinder 10 in which oil is sealed, and the piston rod 11 is extended to the outside. The damping force is generated by controlling the flow of the oil liquid generated by the movement of the piston accompanying the expansion and contraction of the piston rod 11 by a damping force adjusting valve including an orifice and a disc valve. The hydraulic shock absorber 3
The cylinder 10 is inserted into the air spring 5, the cylinder 10 is fixed to the bottom of the lower case 6, and the tip of the piston rod 11 is fixed to the upper mount 9 by a nut 13 via a rubber bush 12.

The electromagnetic damper 4 has a cylindrical outer yoke 14.
It has a double cylinder structure in which a cylindrical center yoke 15 is slidably inserted. The outer yoke 14 is mounted on the upper end via a bush 12 together with the piston rod 11 of the hydraulic shock absorber 3 by means of a cylindrical support member 16 having a substantially bottomed upper end.
9 and the lower end is the lower case 6 of the air spring 2.
And is slidably guided by the dry metal 17. A plurality of coils 18 are wound around the inner periphery of the outer yoke 14 over substantially the entire length.

A plurality of permanent magnets 19 are fixed to the outer periphery of the center yoke 15 so as to face the coil 18 of the outer yoke 14 and are arranged in a ring shape over substantially the entire length. The outer peripheries of the center yoke 15 and the permanent magnet 19 are covered by a thin guide pipe 20. The center yoke 15 has the cylinder 10 of the hydraulic shock absorber 3 inserted therein. You are being guided. A bump stopper 22 is attached to the bottom of the support member 16.

The outer yoke 14, the center yoke 1
5, a magnetic circuit as shown in FIG. 4 is constituted by the coil 18 and the permanent magnet 19, and the coil 18 fixed to the outer yoke 14 and the permanent magnet fixed to the center yoke 15
The relative displacement between 19 and 19 causes an induced electromotive force in coil 18. Coil 18 has lead wire 23
The lead 23 is hermetically inserted into the upper mount 9 and extends to the outside.

The air chamber in the air spring 7 includes an air chamber 24 (chamber) formed in the support member 16 and the outer yoke 14, and an annular air chamber 26 (formed around the center yoke 19 in the lower case 6). ) And an air chamber 27 (chamber) formed on the outer periphery of the outer yoke 14 of the upper case 5 and the diaphragm 7. Here, the volume of the air chamber 24 and the air chamber 26 changes according to the stroke of the hydraulic shock absorber 3 and the electromagnetic damper 4, and is uniquely determined according to the stroke position, whereas the air chamber 27 is , Its volume is air spring
It changes with the stroke 2 and has volume elasticity due to the elasticity of the diaphragm 7.

The air chamber 24 and the air chamber 26 are connected to the center yoke 15
An annular gap 28 (passage) formed between the cylinder and the cylinder 10 and adjacent to the coil 18, a passage 29 provided on the side wall of the center yoke 15, and a passage provided on the side wall of the guide pipe 20.
They are interconnected by 30. Air chamber 24 and air chamber 27
Are connected to each other by a passage 31 provided in the support member 16, and the passage 31 is provided with a reed valve 32 (a check valve) that allows only the flow of air from the air chamber 24 to the air chamber 27. ing. The air chamber 26 and the air chamber 27 are communicated with each other by a passage 33 provided on a side wall of the lower case 6,
The passage 33 is provided with a reed valve (check valve) that allows only the flow of air from the air chamber 27 to the air chamber 26. The reed valves 32 and 34 have a predetermined spring force and act as throttles for the passages 31 and 33, and
A pressure difference is generated between 24 and 27 and between the air chambers 26 and 27.

Next, the operation of the embodiment constructed as described above will be described. A spring force is generated by the pressure of pressurized air sealed in the air chamber of the air spring 2 to support the vehicle body. By supplying and discharging pressurized air in the air chamber by the supply and discharge device via the electromagnetic on-off valve 8, the spring force can be changed and the vehicle height can be adjusted.

The damping force of the hydraulic shock absorber 3 and the electromagnetic damper 4 acts on the stroke of the air spring 2 to dampen the vibration between the sprung and unsprung portions. At this time, by combining the hydraulic shock absorber 3 and the electromagnetic damper 4, the burden on the electromagnetic damper 4 can be reduced.

The electromagnetic damper 4 generates a damping force by controlling the current caused by the induced electromotive force generated in the coil 18 by the resistance means connected to the lead wire 23 by the relative displacement between the coil 18 and the permanent magnet 19. At this time, the coil
The damping force can be controlled by adjusting the current flowing through 18 by a variable resistor or the on-off duty control of the circuit.

Further, power is supplied to the coil 18 so that the coil 18
By applying a current to the coil 18 according to the relative position with respect to the permanent magnet 19, a propulsive force is obtained, and the electromagnetic damper 4 can be operated as an actuator (linear motor), and the outer yoke 14 and the center yoke 15 , A propulsive force is generated between the vehicle and the vehicle to control the posture of the vehicle body.

In this case, for example, the coil 1 of the electromagnetic damper 4
The permanent magnet 8 and the permanent magnet 19 are configured as a three-phase synchronous linear motor, a Hall element (not shown) is mounted on the outer yoke 14 to which the coil 12 is fixed, and based on the output waveform of the Hall element, the coil 18 and the permanent magnet 19 By detecting the relative position of the electromagnetic damper 4, the electromagnetic damper 4 can be operated as a linear motor using a normal three-phase synchronous motor driving driver.

Next, the flow of air in the air spring 2 with the stroke of the electromagnetic suspension device 1 will be described with reference to FIG.
This will be described with reference to FIG.

During the extension stroke of the electromagnetic suspension device 1, as shown in FIG. 2, the air chamber 24 is decompressed by the retraction of the cylinder 10 and the center yoke 15, and the air chamber 26 is
The pressure is reduced by the retreat of the outer yoke 14, and
27 is depressurized by retreating the lower case 6. At this time, since the pressure receiving area of the movable portion hardly changes in each of the air chambers 24, 26, and 27, the volume increases at a substantially constant ratio with respect to the stroke, and the pressure is reduced at that ratio. , Almost the same pressure. However, since the air chamber 27 has volume elasticity due to the diaphragm 7, the volume is reduced correspondingly as the pressure is reduced, and the pressure becomes higher than the other air chambers 24 and 26. Due to this pressure difference,
The reed valve 34 is opened, and the air flows from the air chamber 27 to the air chamber 26, and the air in the air chamber 26 flows to the air chamber 24 through the passages 30, 29 and the annular gap 28.

During the contraction stroke, as shown in FIG. 3, the air chamber 24 is pressurized by the advance of the cylinder 10 and the center yoke 15, and the air chamber 26 is pressurized by the advance of the outer yoke 14. Air chamber 27, lower case 6
Pressurized by the advance of. At this time, each air chamber 24, 2
In Nos. 6 and 27, since the pressure receiving area of the movable portion hardly changes, the volume is reduced at a substantially constant ratio with respect to the stroke, and the pressure is increased at that ratio, so that the pressure is substantially the same. However, since the air chamber 27 has volume elasticity due to the diaphragm 7, the volume is expanded correspondingly with pressurization, and the pressure is lower than those of the other air chambers 24 and 26. This pressure difference causes the reed valve 32 to open, causing air to flow from the air chamber 24 to the air chamber 27, and the air in the air chamber 26 to pass through the passages 30, 29 and the annular gap 28 to the air chamber 24. Flows.

Thus, the electromagnetic suspension device
Since air can be circulated in a certain direction between the air chambers 24, 26, 27 by one stroke, the cylinder 10,
The heat of the coil 18 and the permanent magnet 19 can be diffused throughout the air chamber of the air spring 2, and their cooling can be promoted. That is, since the hot air that has cooled the coil 18 and the permanent magnet 19 does not move around or stay around the coil 18 and the permanent magnet 19, the temperature of the air is efficiently lowered to cool the coil 18 and the permanent magnet 19. be able to.

As a result, a large current can be passed through the coil 18, so that a larger damping force can be generated. In addition, when the electromagnetic damper 4 is used as an actuator and used, a larger propulsive force is generated. be able to. Further, a decrease in magnetic force due to a rise in the temperature of the permanent magnet 19 can be suppressed. Since the thermal expansion of each part can be suppressed, the gap between the coil 18 and the permanent magnet 19 can be reduced, the efficiency of the electromagnetic damper 4 can be increased, and the effect of thermal stress can be reduced to improve durability. Can be improved. Further, deterioration of the hydraulic oil, the seal portion, and the like due to heat can be reduced, and the durability of the hydraulic shock absorber 3 can be improved.

In the above embodiment, the annular gap 28 is formed as an air passage between the cylinder 10 of the hydraulic shock absorber 3 and the center yoke 15. An axial longitudinal groove may be provided so that the center yoke 15 and the cylinder 10 are in close contact with each other. Thus, the center yoke 15 can be firmly supported. The numbers and positions of the passages 29 of the center yoke 15, the passages 30 of the guide pipe 20, the passages 33 of the lower case 6, the passages 32 of the support member 16, and the check valves (reed valves 32, 34) are different from those of the present invention. It can be changed appropriately within the range.

[0029]

As described above in detail, according to the electromagnetic suspension device of the first aspect of the present invention, heat exchange is performed between the air and the coil circulating in one direction in the passage by the stroke of the air spring. As a result, the heat of the coil can be diffused throughout the air chamber, and cooling of the coil can be promoted. As a result, a large current can be passed through the coil, so that a larger damping force can be generated, and when an electromagnetic damper is used as an actuator and used, a larger propulsion force can be generated. According to the electromagnetic suspension device of the second aspect of the present invention, the air flowing through the passage can be reliably circulated in one direction by the throttle or the check valve, thereby promoting heat exchange and increasing cooling efficiency. Can be. Further, according to the electromagnetic suspension device of the invention of claim 3, a pressure difference is generated between the plurality of chambers due to the volume elasticity, and the air can be circulated by the pressure difference.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing the flow of air during the extension stroke of the apparatus of FIG. 1;

FIG. 3 is a diagram showing the flow of air during a contraction stroke of the device of FIG. 1;

FIG. 4 is an explanatory diagram showing a magnetic circuit of the device of FIG. 1;

[Explanation of symbols]

 1 Electromagnetic suspension device 2 Air spring 4 Electromagnetic damper 18 Coil 19 Permanent magnet 24,26,27 Air chamber (chamber) 28 Gap (passage) 32,34 Reed valve (check valve, throttle)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J048 AA05 AC08 BE02 BE09 DA03 EA16 3J069 AA60 EE68

Claims (3)

[Claims] 1. An electromagnetic suspension device in which an electromagnetic damper for controlling a current generated in a coil by a relative displacement between a magnet and a coil to generate a damping force or a propulsion force is disposed inside an air spring, wherein the air chamber is provided. A plurality of chambers are formed, and a passage communicating with the plurality of chambers is arranged adjacent to the coil, and a stroke of the air spring causes air to flow in one direction through the passage between the plurality of chambers. An electromagnetic suspension device for cooling the coil by circulating the coil. 2. The electromagnetic suspension device according to claim 1, wherein a throttle or a check valve is provided in the passage. 3. The electromagnetic suspension device according to claim 1, wherein at least one of the plurality of chambers has a volume elasticity.