JPH07120357A - Eddy current type power absorber and its production method - Google Patents

Abstract

PURPOSE:To provide an eddy current type power absorber and its production method wherein desired power absorption can be performed without generating hysteresis. CONSTITUTION:In the eddy current type power absorber composed of a stator 7, on the circumferential face of which eddy current generation parts 7a, 7b are formed, and a rotor 11 disposed to be rotated around the stator 7, a ladder type copper part 13 is formed on the surface of the eddy current generation parts 7a, 7b. In addition, the surfaces of the eddy current generation parts 7a, 7b are cut in the form of a ladder only down to a specified depth and a ladder member composed of the same size copper as cut depth in thickness is fitted in the cut part, so that the ladder type copper part 13 is formed on the eddy current generation parts 7a, 7b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eddy current type power absorber used as a power absorber in a chassis dynamometer device and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 5 shows a schematic structure of a conventional eddy current type power absorbing device. In this figure, reference numeral 41 is a rotating shaft, and a rotating roller of a chassis dynamometer device is provided via a coupling device (not shown). Connected (not shown).
Reference numeral 42 denotes a stator having a circular shape in a side view and an H-shaped cross-section, which is fixedly provided around the rotary shaft 41, is made of iron, and has an appropriate thickness so that the entire circumferential surface serves as an eddy current generating portion. It is composed of two disk portions 42A and 42B and a horizontal portion 42C connecting them, and an exciting coil 43 is wound around the horizontal portion 42C. A rotor 44 is mechanically coupled to the rotating shaft 41 and rotates together with the rotating shaft 41. The rotor 44 is made of iron and has a plurality of magnetic poles (not shown) formed on the inner surface facing the stator 42 at appropriate intervals. There is.

In the eddy current type power absorber having the above structure, when a current (excitation current) is passed through the exciting coil 43 while the rotor 44 is rotating together with the rotating roller of the chassis dynamometer device, as shown in FIG. For example, magnetic flux in the direction of the arrow indicated by the dotted line is generated, and this magnetic flux causes eddy currents in the eddy current generating portions 42a and 42b of the stator 42. As a result, the eddy current and the magnetic field generated by the exciting coil 43 generate an electromagnetic force (absorption force) in a direction that brakes the rotation of the rotor 44, and the rotational force of the rotating shaft 44 is absorbed. Therefore, by controlling the magnitude of the exciting current supplied to the exciting coil 43 by the current control device or the like, it is possible to perform predetermined power absorption.

[0004]

By the way, in this type of eddy current type power absorber, a large magnetic flux change is required when performing power absorption, and for that purpose, the stator 42 is used.
Also, a large magnetic flux must be passed through the magnetic circuit formed by the rotor 44. When the magnetic flux becomes large in this way, the iron constituting the magnetic circuit causes magnetic saturation and does not supply an exciting current. However, absorption power is generated, and its hysteresis is a problem.

The present invention has been made in view of the above matters, and an object of the present invention is to provide an eddy current type power absorber capable of performing desired power absorption without causing hysteresis and a method for manufacturing the same. There is.

[0006]

To achieve the above object, the present invention comprises a stator having an eddy current generating portion formed on its peripheral surface, and a rotor arranged to rotate around the stator. In the eddy current type power absorber, a ladder-shaped copper portion is formed on the surface of the eddy current generating portion.

Further, according to the method of manufacturing the eddy current type power absorber of the present invention, the surface of the eddy current generating portion made of iron is cut into a ladder shape by a predetermined depth, and the cut portion has a thickness of the above-mentioned cutting. By inserting a ladder member made of copper having the same size as the depth, a ladder-shaped copper portion is formed in the eddy current generating portion.

[0008]

In the eddy current type power absorber having the above structure,
When the exciting current is passed through the exciting coil while the rotor is rotating, the magnetic flux flows vertically to the eddy current generating portion of the stator.
At this time, since the magnetic flux passes through the iron part having a small magnetic resistance, an electromotive force is generated in the ladder-shaped copper part. And since the electric resistance of copper is much smaller than that of iron, a large braking force can be obtained, and it is not necessary to flow a large magnetic flux in the magnetic circuit, so iron is not magnetically saturated and hysteresis is reduced. It will not occur. Further, since the copper portion that originally generates heat is formed so as to be exposed on the surface, the temperature increase in the eddy current generating portion is effectively prevented by cooling this portion with air.

According to the method for manufacturing the eddy current type power absorber, the ladder-shaped copper portion can be easily formed in the eddy current generating portion.

[0010]

1 and 2 show an example of the structure of an eddy current type power absorber according to the present invention. In these figures, 1 is, for example, an iron pedestal, and a rotary shaft via a bearing 2 3 is rotatably held. The rotating shaft 3 is mechanically coupled to rotate with the rotating roller 4 of the chassis dynamometer device via a coupling device (not shown). In addition, in FIG. 1, 5 is a drive wheel of the test vehicle 6.

Reference numeral 7 denotes a stator having a circular shape in a side view and a substantially H-shaped cross section, which is fixedly provided around the rotary shaft 3 via a bearing 8 and is made of iron, and the entire peripheral surface thereof serves as an eddy current generating portion. As described above, it is composed of two disk portions 7A and 7B having an appropriate thickness and a horizontal portion 7C connecting them, and is joined and held to the pedestal 1 by the screw member 9. Reference numeral 10 denotes an exciting coil wound around the horizontal portion 7C of the stator 7.

Reference numeral 11 denotes a rotor which is mechanically coupled to the rotating shaft 3 and rotates together with the rotating shaft 3. The rotor 11 is made of iron and has a plurality of inner surfaces opposed to the eddy current generating portions 7a and 7b of the stator 7 and arranged at appropriate intervals. The magnetic pole 12 is formed. The configuration so far is no different from the conventional eddy current type power absorber.

This embodiment is largely different from the conventional eddy current type power absorber of this kind in that FIG.
As shown in (A) and (B), the ladder-shaped copper portion 1 is provided over the entire circumference of the eddy current generating portions 7a and 7b in the stator 7.
3 is formed. Note that FIG. 3A is a top view showing, for example, a part of the eddy current generating unit 7a in a developed manner,
FIG. 3B is a front view thereof.

As is apparent from FIG. 3, the iron portion 14 that is the portion that originally generates the eddy current is the ladder-shaped copper portion 1.
Surrounded by 3. Then, the eddy current generator 7a,
In order to make 7b such a shape, for example, as shown in FIG. 4 (A), the surface of the eddy current generators 7a and 7b has a depth d.
A ladder member 15 made of copper having the same thickness as the depth d, as shown in FIG.
By fitting the above into the cut portion and welding the end, the desired ladder-shaped copper portion 13 can be easily formed in the eddy current generating portions 7a and 7b.

In the eddy current type power absorber constructed as described above, when the rotor 11 is rotating, 10 exciting currents are supplied to the exciting coil, whereby the stator 7 is rotated.
Magnetic flux flows perpendicularly to the eddy current generators 7a and 7b, and eddy currents are generated in the eddy current generators 7a and 7b. At this time, the magnetic flux passes through the iron portion 14 having a small magnetic resistance, and an electromotive force is generated in the ladder-shaped copper portion 13. In this case, the electrical resistance of copper is much smaller than that of iron, so a large braking force can be obtained, and the magnetic circuit does not need to flow a very large magnetic flux, so iron is not magnetically saturated, Hysteresis does not occur.

Since the eddy current is exponentially attenuated, a sufficient effect can be obtained if the depth (dimension d or h) of the copper portion 13 in the eddy current generating portions 7a and 7b is about 6 mm. Was confirmed.

Further, in the eddy current type power absorber, since the copper portion 13 that originally generates heat is formed so as to be exposed on the surface, the eddy current generating portion 7a is cooled by being cooled by air. , 7b are effectively prevented from increasing in temperature.

[0018]

As described above, according to the present invention, since the ladder-shaped copper portion is formed on the surface of the eddy current generating portion, a large eddy current can be generated with a small change in magnetic flux. As a result, it is not necessary to apply a large magnetic flux to the magnetic circuit, so that hysteresis does not occur in the magnetic circuit and the exciting current can be reduced. Therefore, it is possible to obtain an eddy current type power absorption device which has a higher performance and is cheaper than the conventional device of this type.

Further, since the copper portion, which originally generates heat, is formed so as to be exposed on the surface, by cooling this portion with air, the temperature rise in the eddy current generating portion is effectively prevented. It

Further, according to the method of manufacturing the eddy current type power absorber of the present invention, the ladder-shaped copper portion can be easily formed in the eddy current generating portion.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an example of the configuration of an eddy current type power absorber according to the present invention.

FIG. 2 is a cross-sectional view showing a configuration of a main part of the eddy current power absorber.

FIG. 3 (A) is a top view showing a part of an eddy current generator in the eddy current type power absorber in a developed state, and FIG. 3 (B) is a front view thereof.

FIG. 4A is a cross-sectional view showing a cut state of the eddy current generating portion, and FIG. 4B is a view showing an example of a cross-sectional shape of a ladder member fitted into the cut portion.

FIG. 5 is a diagram for explaining a conventional technique.

[Explanation of symbols]

7 ... Stator, 7a, 7b ... Eddy current generating part, 11 ... Rotor, 13 ... Ladder-like copper part.

Claims (2)

[Claims] 1. An eddy current type power absorber comprising a stator having an eddy current generating portion formed on its peripheral surface and a rotor arranged so as to rotate around the stator. An eddy current type power absorber characterized in that a ladder-shaped copper portion is formed on the inner surface. 2. A surface of an eddy current generating part made of iron is cut into a ladder shape by a predetermined depth, and a ladder member made of copper having a thickness equal to the cutting depth is fitted into the cut part. According to the method, a ladder-shaped copper part is formed in the eddy current generating part.