JP2002223556A - Eddy current type deceleration device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit drag torque that is generated, when braking is turned off, without losing the braking force when braking is on. SOLUTION: The eddy current type deceleration device is in a single-row turning system. A support ring 2 is divided into two portions in the radial direction, so that the sectional area of the support ring 2 between adjacent permanent magnets 3 is large at braking, and the support ring 2 between the adjacent permanent magnets 3 is small at non-braking. The braking force when damping is on is not impaired, thus inhibiting magnetic flux that is generated from the permanent magnets when braking is off, to necessarily decrease the magnetic flux which leaked to the cylindrical section of a rotor from a switch board, accompanied by the decrease in the magnetic flux that is generated from the permanent magnets when braking is off, and inhibiting drag torque.

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 speed reducer mounted on a large vehicle such as a bus or a truck as a brake assist device.

[0002]

2. Description of the Related Art In recent years, large vehicles such as buses and trucks perform stable deceleration on long downhills and the like to reduce the number of times a foot brake is used, thereby preventing abnormal wear of a lining and a fade phenomenon. At the same time, in order to shorten the braking stop distance, an eddy current type speed reducer has been mounted in addition to a foot brake which is a main brake and an exhaust brake which is an auxiliary brake. As the eddy current type speed reducer, there are a type using an electromagnet and a type using a permanent magnet as a magnet. I have.

As an eddy current type speed reducer using this permanent magnet, for example, the one proposed by the present applicant in Japanese Patent Application No. 1-298948 is integrally mounted on a rotating shaft as shown in FIG. A rotor 1 and a group of permanent magnets 3 supported opposite to the rotor 1 and arranged uniformly on a ferromagnetic support ring 2 so that the magnetic poles are opposite to each other along the circumferential direction of the rotor 1. And a group of ferromagnetic switch plates 4 equally disposed by the same number as the number of the permanent magnets 3 between the group of permanent magnets 3 and the rotor 1. Nonmagnetic support 5 interposed between
A predetermined gap is maintained between the outer peripheral surface of the permanent magnet 3 and the inner peripheral surface of the switch plate 4.
In FIG. 7, 1a is a cylindrical portion of the rotor 1, 1b is a cooling fin of the rotor 1, 6 is a driving portion for reciprocatingly rotating the support ring 2 by a predetermined angle, and 7 is an inner peripheral surface side and both side wall sides of the support ring 2. And bearings respectively interposed between the support ring 5 and the support member 5 for rotatably supporting the support ring 2.

In the eddy current type speed reducer proposed in Japanese Patent Application Laid-Open No. 1-298948, when the support ring 2 is rotated so that the permanent magnet 3 overlaps the switch plate 4 as shown in FIG. , Support ring 2, adjacent permanent magnet 3, adjacent switch plate 4, and cylindrical portion 1a of rotor 1.
As a result, a magnetic circuit is formed as shown by an arrow, and a so-called braking ON state is established. The magnetic flux from the permanent magnet 3 acts on the cylindrical portion 1a to generate an eddy current, thereby generating a braking torque.

Therefore, a high braking force can be obtained by passing a large amount of magnetic flux through the magnetic circuit including the rotor 1 during braking. Therefore, it is necessary to sufficiently increase the magnetic capacitance of the circuit components such as the support ring 2 and the switch plate 4 during braking and to reduce the magnetic resistance on the magnetic circuit during braking, thereby increasing the braking efficiency and increasing the cost of permanent magnets. Can be saved, leading to cost reduction.

[0008] Further, the support ring 2 is turned from the above-mentioned braking ON position, and as shown in FIG. 8 (b), one permanent magnet 3 overlaps the adjacent switch plate 4 so as to half overlap each other. , The support ring 2, the adjacent permanent magnet 3, and one switch plate 4, a short-circuit magnetic circuit is formed as shown by an arrow, and a so-called braking OFF state is established.

In this state, it is ideal that an eddy current does not flow through the above-mentioned cylindrical portion 1a and no braking torque is generated. However, since the switch plate 4 and the cylindrical portion 1a are close to each other, in reality, FIG. As shown by a broken line in FIG.
Part of the magnetic flux passing through the cylindrical portion 1a of the rotor 1 enters the cylindrical portion 1a and generates drag torque in the cylindrical portion 1a, and the power loss caused by this causes problems such as deterioration of fuel efficiency.

Therefore, in order to prevent the generation of the drag torque, conventionally, in order to suppress the invasion of magnetic flux from the switch plate to the cylindrical portion of the rotor, the cross-sectional area of the switch plate in the circumferential direction is made sufficiently large. It was easy to pass the magnetic flux between the plates.

[0009]

However, as described above, the technique of increasing the circumferential cross-sectional area of the switch plate necessarily increases the thickness of the switch plate.
This has caused a vicious cycle in which the magnetic resistance of the magnetic circuit at the time of braking increases and the braking efficiency decreases.

The present invention has been made in view of the above-mentioned conventional problems, and suppresses a magnetic flux generated from a permanent magnet at the time of braking OFF without impairing a braking force at the time of braking ON. It is an object of the present invention to provide an eddy current type reduction gear capable of suppressing a magnetic flux leaking into a cylindrical portion of a rotor and suppressing a drag torque.

[0011]

In order to achieve the above object, an eddy current type speed reducer according to the present invention is represented by the following formula (1) of a support ring in a single-row turning type eddy current type speed reducer. Κ = 0.08-
0.12, or the support ring is divided into two in the radial direction, the cross-sectional area of the support ring between adjacent permanent magnets is large during braking, and the support ring between adjacent permanent magnets is non-braking. Are configured to have a small cross-sectional area. By doing so, the magnetic flux generated from the permanent magnet is suppressed at the time of braking OFF, the magnetic flux leaking from the switch plate to the cylindrical portion of the rotor is suppressed without damaging the braking force at the time of braking ON, and the drag torque is reduced. It can be suppressed.

[0012]

A = κ · (BHmax · W / ρ) / Br where BHmax: maximum energy product of the permanent magnet used (J / m ³ ) W: Permanent magnet mass per unit (kg) ρ: Used to the permanent magnet specific gravity (kg / m ³⁾ a: circumferential direction of the cross-sectional area in the support ring (m ²⁾ Br: saturation magnetic flux density of the support ring in the magnetic field strength 5000A / m (T)

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 5 and 6 show magnetic circuits during braking and non-braking of an eddy current type speed reducer of a single-row turning type.
FIGS. 5 and 6 show the magnetic flux flowing through the magnetic circuit as a current circuit as a current circuit for easy understanding.

At the time of braking shown in FIG. 8 (a), for example, the magnetic flux flowing out of the permanent magnet 3 on the left side of the drawing shows a gap between the permanent magnet 3 on the left side of the drawing and the switch plate 4 → the switch plate 4 on the left side of the drawing. → A gap between the switch plate 4 on the left side of the drawing and the cylinder 1a of the rotor → A gap between the cylinder 1a of the rotor and the switch plate 4 on the right side of the drawing through the cylinder 1a of the rotor → A switch plate 4 on the right side of the drawing → A switch on the right side of the drawing The gap between the plate 4 and the permanent magnet 3 → the support magnet 2 returns to the permanent magnet 3 on the left side of the drawing.

FIG. 5 shows the current flowing through the magnetic circuit during braking.
In FIG. 5, the circuit is replaced.
The permanent magnet 3 is considered to be equivalent to a power supply and is represented by BH.
ing. Also, a circumferential section of the support ring 2 (FIG. 8A)
AA cross-section at R)_{y (A)},permanent magnet
The resistance of the gap between the switch 3 and the switch plate 4 is represented by R_Gap1, Sui
8 (a sectional view taken along the line BB in FIG. 8A).
Surface) has a resistance of R _{P (A)}, Switch plate 4 and rotor circle
The resistance of the gap between the cylinders 1a is R_Gap2, Rotor cylinder 1
a in the circumferential direction (CC section in FIG. 8A)
R_DThink.

In the current circuit shown in FIG. 5, when the total resistance during braking is R _ON , the current (magnetic flux) I during braking is
The magnitude of _ON can be represented by I _ON ∝BH / R _ON . Here, R _ON = (R _Gap1 + R _{P (A)} + R _Gap2 ) × 2 +
Since R _D + R _{y (A)} , R _ON ≫R
_{y (A)} .

On the other hand, in the non-braking state shown in FIG. 8 (b), for example, the magnetic flux flowing out of the permanent magnet 3 on the left side of the drawing is a gap between the permanent magnet 3 on the left side of the drawing and the switch plate 4 at the center of the drawing → the drawing. The switch plate 4 at the center → the gap between the switch plate 4 at the center of the drawing and the permanent magnet 3 on the right side of the drawing → returns to the permanent magnet 3 on the left side of the drawing through the support ring 2.

The drag torque at the time of non-braking shown in FIG. 8 (b), for example, flows out of the permanent magnet 3 on the left side of the drawing and the gap between the permanent magnet 3 on the left side of the drawing and the switch plate 4 at the center of the drawing → paper drawing. A part of the magnetic flux that has passed through the central switch plate 4 is transmitted to the central switch plate 4 and the rotor cylinder 1.
a, and flows into the rotor cylinder 1a through the gap between the rotor cylinder 1a and the switch plate 4 in the center of the paper → the switch plate 4 in the center of the paper → the switch plate 4 in the center of the paper and the permanent magnet 3 on the right side of the paper. The gap is caused by returning to the permanent magnet 3 on the left side of the drawing through the support ring 2.

FIG. 6 shows a state in which the magnetic circuit during the non-braking operation is turned on.
The circuit is replaced with a current circuit, as shown in FIG.
In the current circuit, the circumferential direction of the switch plate 4 (FIG. 8B)
The cross section taken along the line DD in FIG._{P (t)}, All non-braking
R_OFF , The current (magnetic flux) I during non-braking_OFF 
The size of I_OFF ∝BH / R_OFF Can be represented by
You. Where R_OFF = 2 · R_Gap1+ R '+ R_{y (A)}But
And 1 / R '= (1 / R _{P (t)}) + 1 / (2 · R_{P (A)}+2
・ R_Gap2+ R_D ), R
_OFF > R_{y (A)}Becomes

The magnetic resistances R _Gap1 and R _{Gap2 of the gap}
Is much larger than the magnetic resistances R _{P (A)} , R _{P (t)} , R _D , and R _{y (A)} of the switch plate 4, the rotor cylinder 1a, and the support ring 2, so that R _ON ≫ R _OFF , and the effect of the support ring 2 is small during braking and large during non-braking. Therefore, by reducing the circumferential cross-sectional area of the support ring 2, the flow of magnetic flux during non-braking, and hence the drag torque, can be reduced.

An eddy current type speed reducer according to a first aspect of the present invention comprises:
This is based on the above-described concept, and a rotor integrally mounted on a rotating shaft and a rotor supported opposite to the rotor so that the directions of magnetic poles are opposite to each other along the circumferential direction of the rotor. A permanent magnet group evenly arranged on the ferromagnetic support ring; and a ferromagnetic switch plate group equally interposed between the permanent magnet group and the rotor by the same number as the permanent magnets. In the eddy current type reduction gear having a nonmagnetic support member interposed between the switch plates of the switch plate group, the circumferential cross-sectional area A of the support ring represented by the above equation 1 is κ = 0.08-0.1
2 is set.

In the eddy current type speed reducer according to the first aspect of the present invention, the cross-sectional area A of the support ring in the circumferential direction represented by the above equation 1 is in the range of κ = 0.08 to 0.12. The reason is that in the eddy current type speed reducer of the single-row turning type, the circumferential cross-sectional area A
Is changed (when κ is changed), the braking torque and the drag torque are measured.

FIG. 1 shows the measurement results of the braking torque and the drag torque when the cross-sectional area A of the support ring in the circumferential direction was changed (when κ was changed).
Is greater than 0.12, the braking torque is saturated. When κ is less than 0.08, it can be seen that the rate of decrease in the drag torque does not change much, but the braking torque drops significantly.

According to the results, the cross-sectional area A of the support ring in the circumferential direction of the support ring obtained by the above equation 1 in the single-row turning type eddy current type speed reducer is such that κ is in the range of 0.08 to 0.12. In the case of a sectional area, for example, in an eddy current type speed reducer having the following specifications, the braking torque is 90% of the maximum generated torque.
The above can be secured, and the drag torque at the time of braking OFF can be suppressed to 18 to 28% of the maximum value.

Specification of single-row turning type eddy current type speed reducer BHmax: 360 (kJ / m ³ ) W: 199 (g / piece) ρ: 7.5 × 10 ³ (kg / m ³ ) κ = 0. A at time of 1: 586 (mm ² ) Br: 1.63 (T)

In the eddy current type speed reducer according to the first aspect of the present invention, the magnetic flux density Br of the support ring is set to 50
The saturation magnetic flux density at 00 A / m is used not only when the material is different, but also when the same material has a different magnetic field strength, the magnetic flux density Br is different.
This is because if only r is determined, the applicable support ring becomes ambiguous.

An eddy current type speed reducer according to a second aspect of the present invention has a rotor integrally mounted on a rotating shaft, and is supported opposite to the rotor, and has magnetic poles extending along the circumferential direction of the rotor. And a permanent magnet group equally disposed on the ferromagnetic support ring so as to be opposite to each other, and the same number of permanent magnets as the number of the permanent magnets interposed between the permanent magnet group and the rotor. In an eddy current type speed reducer having a switch plate group of a magnetic material and a support portion of a non-magnetic material interposed between the switch plates of the switch plate group, the support ring is divided into two in a radial direction, and braking is performed. In some cases, the cross-sectional area of the support ring between adjacent permanent magnets is large, and the cross-sectional area of the support ring between adjacent permanent magnets is small when braking is not performed.

In the eddy current type speed reducer according to the second aspect of the present invention, when one permanent magnet is in a braking OFF state in which the two permanent magnets overlap each other over an adjacent switch plate, the support ring between the adjacent permanent magnets is disconnected. Since the area is reduced, the magnetic flux generated from the permanent magnet is suppressed, the magnetic flux leaking to the cylindrical portion of the rotor can be reduced, and the drag torque is reduced.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An eddy current speed reducer according to the present invention will be described below with reference to the embodiments shown in FIGS. 2 to 4
7 and 8 denote the same or corresponding parts, and a detailed description thereof will be omitted. FIG. 2 is a cross-sectional view showing a first embodiment of the eddy current type speed reducer of the second invention in the direction of the rotation axis, and FIG.
FIG. 3 (b) is an explanatory view showing a brake ON state, FIG. 3 is a cross-sectional view showing a second embodiment of the eddy current type speed reducer of the second invention in the rotation axis direction, and FIG. FIG. 4B is an explanatory diagram showing a state, FIG.
3A is a cross-sectional view showing a third embodiment of the eddy current type speed reducer of the present invention in the direction of the rotation axis, and FIG.
(B) is an AA cross-sectional view of (a), (c) is a view of arrow B of (a) showing a state of braking OFF, and (d) is a view B of arrow (a) of FIG. FIG.

An eddy current type speed reducer according to a first aspect of the present invention comprises:
For example, a permanent magnet having a density ρ of 7500 kg / m ³ and a mass W per unit of 199 g is used as a maximum energy product BHmax.
Is 360 kJ / m ³ , the supporting ring made of a material having a saturation magnetic flux density Br of, for example, 1.63 T when the magnetic field strength is 5000 A / m. , The circumferential cross-sectional area A is 468.8 mm ²
To 703.2 mm ² , that is, κ in Expression 1 is set in the range of 0.08 to 0.12.

By setting the circumferential cross-sectional area A of the support ring in the above range, the braking force when the brake is ON is not impaired, and the magnetic flux generated from the permanent magnet when the brake is OFF is suppressed. The magnetic flux leaking from the rotor to the cylindrical portion of the rotor can be suppressed, and the drag torque can be suppressed.

FIGS. 2 to 4 show a case where the supporting ring is replaced with a supporting ring in the same manner as in the eddy current type speed reducer according to the first embodiment of the present invention. The second aspect of the present invention, which is divided into two parts in the radial direction so that the cross-sectional area of the support ring between adjacent permanent magnets is large during braking and the cross-sectional area of the support ring between adjacent permanent magnets is small during non-braking. 1 shows a specific embodiment of the eddy current type speed reducer according to the present invention.

That is, in the first embodiment shown in FIG. 2, the support member 5 which is located on the inner peripheral side of the radially divided two parts.
Groove 1 reaching the entire width direction at a position facing the circumferential center of the switch plate 4 in the first support ring 11 fixed to
1a.

In this manner, the permanent magnets 3 which are evenly installed on, for example, the outer peripheral surface of the second support ring 12 located on the outer peripheral side of the radially divided two parts are replaced with the switch plate 4.
In the braking ON state shown in FIG. 2B opposed to the above, the circumferential cross-sectional area of the support ring increases (substantially the same as the circumferential cross-sectional area of the conventional support ring 2), and the braking torque is impaired. Nothing.

The second support ring extends from the braking ON state shown in FIG. 2B to the braking OFF state shown in FIG. 2A in which one permanent magnet 3 overlaps the adjacent switch plate 4 by half each other. When the support ring 12 is turned, the circumferential cross-sectional area of the support ring is reduced by the provision of the concave groove 11a, and the magnetic flux flowing through the short-circuit magnetic circuit is reduced. Leakage magnetic flux decreases,
Drag torque is reduced. In addition, 14 in FIG.
This is a bearing provided between the support ring 11 and the second support ring 12.

Further, in the second embodiment shown in FIG. 3, instead of the first embodiment shown in FIG. The apex angle of the polygon is arranged so as to face the center of the switch plate 4 substantially in the circumferential direction, and the outer peripheral surface of the support 5 is located on the inner circumferential side of the radially divided two. First support 1
3 are arranged at predetermined intervals between adjacent first support members 13.

The second embodiment shown in FIG. 3 has the same operation and effect as the first embodiment shown in FIG. In FIG. 3, reference numeral 14 denotes a bearing provided between the first support 13 and the second support ring 12.

In the third embodiment shown in FIG. 4, one side in the width direction of the first support ring 11 of the first embodiment shown in FIG. 11a is cut out at the same height as the bottom of the second support ring 1b.
The two opposing portions are made to protrude, and this protruding portion 12a is made to oppose the notch 11b.

The third embodiment shown in FIG. 4 has the same operation and effect as the first embodiment shown in FIG.

[0040]

As described above, according to the eddy current type speed reducer of the present invention, it is possible to suppress the magnetic flux generated from the permanent magnet when the brake is OFF without damaging the braking force when the brake is ON. . Accordingly, as the magnetic flux generated from the permanent magnet at the time of braking OFF is reduced, the magnetic flux leaking from the switch plate to the cylindrical portion of the rotor is inevitably reduced, and the drag torque can be suppressed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an eddy current type speed reducer of the first invention,
FIG. 8 is a diagram showing the results of measuring the braking torque and the drag torque when the cross-sectional area A of the support ring in the circumferential direction obtained by Expression 1 is changed (when κ is changed).

FIGS. 2A and 2B are cross-sectional views showing a first embodiment of the eddy current type speed reducer according to the second aspect of the present invention in the direction of the rotation axis, wherein FIG. It is explanatory drawing which shows the state.

FIGS. 3A and 3B are cross-sectional views showing a second embodiment of the eddy current type speed reducer of the present invention in the rotation axis direction, wherein FIG. 3A is an explanatory diagram showing a state where braking is OFF, and FIG. It is explanatory drawing which shows the state.

FIGS. 4A and 4B are sectional views showing a third embodiment of the eddy current type speed reducer according to the second aspect of the present invention in the rotation axis direction, where FIG. 4A is a view showing a circumferential section, and FIG. 3A is a cross-sectional view taken along the line AA, FIG. 3C is a view B in an arrow direction of FIG. 3A showing a brake OFF state, and FIG. 3D is a view B in an arrow direction of FIG.

FIG. 5 is a diagram in which the magnetic circuit at the time of braking shown in FIG. 8A is replaced with a current circuit.

FIG. 6 is a diagram in which the magnetic circuit at the time of non-braking shown in FIG. 8B is replaced with a current circuit.

FIG. 7 is a side view of an eddy current type reduction gear proposed in Japanese Patent Application Laid-Open No. 1-298948, in which an upper half is shown in cross section.

8A and 8B are explanatory diagrams showing a magnetic circuit configuration in the eddy current type reduction gear of FIG. 7, in which FIG. 8A shows a brake ON state, and FIG. 8B shows a brake OFF state.

[Explanation of symbols]

 1a cylindrical part 2 support ring 3 permanent magnet 4 switch plate 11 first support ring 11a concave groove 11b notch 12 second support ring 12a protrusion 13 first support

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Mitsuo Miyahara 4-5-33 Kitahama, Chuo-ku, Osaka-shi, Osaka F-term (reference) in Sumitomo Metal Industries, Ltd. 5H649 AA03 BB02 BB07 GG09 GG13 GG16 HH08 HH16 JK03 PP02 PP08 PP13

Claims (2)

[Claims] 1. A rotor integrally mounted on a rotating shaft, and a ferromagnetic support ring supported opposite to the rotor and having magnetic poles opposite to each other along the circumferential direction of the rotor. A permanent magnet group evenly arranged in the same manner, a ferromagnetic switch plate group equally interposed between the permanent magnet group and the rotor by the same number as the permanent magnets, and each of the switch plate group. In an eddy current type reduction gear having a non-magnetic support member interposed between switch plates, a circumferential cross-sectional area A of a support ring represented by the following equation is κ
= 0.08 to 0.12. An eddy current type speed reducer, characterized in that: 0.08 to 0.12. A = κ · (BHmax · W / ρ) / Br where BHmax: maximum energy product of the permanent magnet used (J / m ³ ) W: Permanent magnet mass per unit (kg) ρ: Permanent magnet used Specific gravity (kg / m ³ ) A: Cross-sectional area of support ring in circumferential direction (m ² ) Br: Saturation magnetic flux density of support ring at magnetic field strength of 5000 A / m (T) 2. A rotor integrally mounted on a rotating shaft, and a ferromagnetic support ring supported opposite to the rotor and having magnetic poles opposite to each other along a circumferential direction of the rotor. A permanent magnet group evenly arranged in the same manner, a ferromagnetic switch plate group equally interposed between the permanent magnet group and the rotor by the same number as the permanent magnets, and each of the switch plate group. In an eddy current speed reducer having a non-magnetic support member interposed between switch plates, the support ring is divided into two parts in a radial direction, and the cross-sectional area of the support ring between adjacent permanent magnets is increased during braking. An eddy current type reduction gear characterized in that the cross-sectional area of the support ring between adjacent permanent magnets is reduced when braking is not performed.