JP2004153925A - Ferromagnetic plate and eddy current type reduction gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ferromagnetic plate and an eddy current type reduction gear that increase the density of a line of magnetic force that goes toward a rotor from a permanent magnet via a pole piece, increase the density of a line of magnetic force that enters the rotor from the rear rotational side of the pole piece, make the line of magnetic force from the permanent magnet easily enter the rotor via the pole piece, make the line of magnetic force from the rotor easily enter the pole piece, and improve braking torque particularly when braking. <P>SOLUTION: The pole piece 4 is arranged so as to oppose the permanent magnets 5, 5a and 5b of the eddy current type reduction gear. Between external and internal peripheries of the pole piece 4, throttled parts 4a each having a cross section smaller than the internal peripheral surface, or than the external peripheral surface, or than the area of the external peripheral surface are formed at either the external periphery or the internal periphery. A forward protrusion 4c and a backward protrusion 4b are formed for braking, which are formed such that forward and backward external peripheral sides facing traveling directions of rotations of the rotors 2a, 2b are flatly protruded. A projected shape viewed from the upper side of a main surface is spread toward the front side or the backside facing the traveling directions of the rotations. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a ferromagnetic plate of an eddy current type speed reducer which is attached to a large vehicle such as a bus or a truck as a braking auxiliary device and which can improve braking torque, and an eddy current type speed reducer employing the ferromagnetic plate. It is about.
[0002]
[Prior art]
In recent years, stable deceleration has been performed on long downhills, etc., and the number of times the foot brake has been used has been reduced to prevent abnormal lining wear and fade phenomena. Eddy current type reduction gears have been attached to large vehicles in addition to foot brakes and exhaust brakes.
[0003]
At present, the eddy current type reduction gear is mainly of a permanent magnet type which does not need to be energized at the time of braking, and there are the following four types.
{Circle around (1)} As shown in FIG. 12, for example, a non-magnetic member is provided on the inner peripheral surface side of a drum-shaped member (hereinafter referred to as “rotor”) 2a which is attached to the rotating shaft 1 and generates an eddy current inside during braking. N poles and S poles at the same interval as the pole pieces 4 via a group of ferromagnetic plates (hereinafter referred to as "pole pieces") 4 arranged at predetermined intervals in the circumferential direction between the supports 3 A ferromagnetic magnet support ring 6 having permanent magnets 5 arranged alternately in the circumferential direction attached to the outer peripheral surface thereof is arranged, and the permanent magnets 5 are entirely opposed to the pole pieces 4 by the magnet support ring 6. (See, for example, Japanese Patent Application Laid-Open No. 1-234043).
[0004]
{Circle around (2)} As shown in FIG. 13, a permanent magnet 5 in which a magnet support ring 6 disposed on the inner peripheral surface side of the rotor 2 a so as to face the same is attached to the outer peripheral surfaces of the pole piece 4 and the magnet support ring 6. (See Japanese Patent Application Laid-Open No. 1-298948) in which a single row turning system is provided so as to be able to turn so that a position at which a permanent magnet 5 overlaps and a position at which one permanent magnet 5 overlaps by half over an adjacent pole piece 4 can be selected. .
[0005]
(3) For example, as shown in FIG. 14, two magnet support rings each having a permanent magnet group in which N poles and S poles are alternately arranged on the outer peripheral surface at predetermined intervals along the circumferential direction thereof are arranged in parallel, One of the magnet support rings is fixed (hereinafter, referred to as a “fixed support ring 6a”), and the other magnet support ring is configured to be rotatable by a predetermined angle (hereinafter, referred to as a “movable support ring 6b”). Due to the turning movement of the ring 6b, the position where the permanent magnet 5b of the movable support ring 6b and the permanent magnet 5a of the fixed support ring 6a adjacent to each other have the same polarity, and the position of the permanent magnet 5b of the adjacent movable support ring 6b and the fixed support ring 6a. A double-row turning system (for example, Japanese Patent Application Laid-Open No. 4-12659) in which a position where the permanent magnet 5a has a different polarity can be selected.
[0006]
{Circle around (4)} As shown in FIG. 15, for example, at a position facing the disk-shaped rotor 2 b attached to the rotating shaft 1, the non-magnetic support 3 is disposed at a predetermined interval in the circumferential direction thereof. Through the group of pole pieces 4, a ferromagnetic magnet support ring 6 having permanent magnets 5 in which N poles and S poles are alternately arranged in the circumferential direction at the same intervals as the pole pieces 4 is attached to the side face, A shaft-sliding method using a disk-type rotor provided with the magnet support ring 6 so as to be able to move forward and backward in the case by an actuator 7 from a position where the group of permanent magnets 5 is entirely opposed to a group of pole pieces 4 to a position where the permanent magnet is completely separated.
[0007]
In any of the above-described eddy current type speed reducers, the magnet support ring 6 is adjacent to the pole support 4 and the permanent magnets 5, 5a, 5b during braking in which the entire surface is opposed. A magnetic circuit is formed between the permanent magnets 5, 5a, 5b and the adjacent pole pieces 4, and the rotors 2a, 2b. Lines of magnetic force from the permanent magnets 5, 5a, 5b act on the rotors 2a, 2b to generate eddy currents. And a braking torque is generated.
[0008]
In order to efficiently generate the braking force, it is necessary to input the magnetic lines of force constituting the magnetic circuit perpendicularly to the rotor surface. Among the magnetic lines of force input from the pole piece 4 to the rotor surface at the time of braking, as shown by the thin line in FIG. 16, the rotor 2a, 2b moves forward in the direction of rotation (hereinafter simply referred to as “rotation forward”). The lines of magnetic force input from the side of ()) contain many components that are input vertically.
[0009]
[Problems to be solved by the invention]
However, conventionally, the shape of the pole piece 4 is a substantially rectangular parallelepiped, and the length in the rotation (circumferential) direction on the inner peripheral side is substantially the same as the outer peripheral surface length of the permanent magnet 5 as shown in FIG. . Therefore, the magnetic circuit formed at the time of the braking is distorted in such a manner as to be dragged in the direction of rotation of the rotors 2a and 2b as shown by the thin line in FIG. As a result, there is a drawback that, even among the lines of magnetic force input from the rotation front side of the pole piece 4, those input perpendicular to the rotors 2a and 2b decrease, and the braking force decreases.
[0010]
The present invention has been made in view of the above-mentioned conventional problems, and in particular, a pole piece of an eddy current type reduction device capable of improving braking torque during braking, and an eddy current type deceleration employing the pole piece. It is intended to provide a device.
[0011]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention provides a pole piece disposed opposite to a permanent magnet of an eddy current type reduction gear, in a forward or rearward direction (hereinafter simply referred to as “rotation”) in a direction in which a rotor rotates. The outer peripheral side of “front” and “rotational rear” is projected in a flat plate shape, and a narrowed portion having a cross-sectional area smaller than the area of the inner peripheral surface is provided between the inner and outer peripheries of the pole piece. . This makes it possible to improve the braking torque particularly during braking.
[0012]
By the way, the description “front or rear” includes any one of the front and rear, and all cases of both front and rear. The same applies to the description “front side or rear side” and “front projection or rear projection”. Further, the expression “inner peripheral surface or outer peripheral surface” also includes any one of the inner peripheral surface and the outer peripheral surface and all cases of both the inner peripheral surface and the outer peripheral surface.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, a portion having a sectional area smaller than the area of the inner peripheral surface of the pole piece 4 facing the permanent magnets 5, 5a, 5b (substantially the same as the area of the permanent magnets 5, 5a, 5b) or the area of the outer peripheral surface. That is, as shown in FIG. 3A, the installation position of the portion 4a narrowed so as to have a cross-sectional area smaller than the above-mentioned area (hereinafter, referred to as a "restricted portion") is located inside and outside the pole piece 4. Not only the intermediate part between the circumferences, but also the outer peripheral part of the pole piece 4 as shown in FIG. 3B or the inner peripheral part of the pole piece 4 as shown in FIG. good. Further, since the cross-sectional area only needs to be reduced, the length of the rotor in the rotational (circumferential) direction is not limited to be reduced, and the length in the direction of the rotation axis perpendicular to the rotor is reduced, or both. May be shortened.
[0014]
In the eddy current type reduction gear according to the present invention, since the pole piece 4 according to the present invention having the throttle portion 4a is used, as shown in FIG. 4 (a), during braking, the permanent magnets 5, 5a, 5b The density of the lines of magnetic force traveling toward the rotors 2a and 2b via the pole piece 4 is higher than that using a conventional pole piece 4 (see FIG. 4B) having a constant cross-sectional area between the inner and outer circumferences.
[0015]
When the magnetic field lines having the increased density reach the rotors 2a and 2b, a large eddy current is generated, and a large Lorentz force is obtained. Therefore, as described above, for example, the magnetic field lines input vertically by being dragged by the rotation of the rotors 2a and 2b. , The overall braking force improves.
[0016]
In the eddy current type speed reducer according to the present invention, in addition to the above-described throttle portion 4a, the pole piece 4 according to the present invention is used in which the outer peripheral side behind the rotation is protruded in a flat plate shape from the permanent magnets 5, 5a, 5b. I do. As shown in FIG. 5A, when the brake is not applied, the magnetic leakage from the permanent magnets 5, 5a, 5b to the rotors 2a, 2b via the support 3 is caused by the rear protruding portion 4b protruding in the flat shape. Since it is absorbed, the torque loss can be reduced as compared with the conventional pole piece 4 without the rear protruding portion 4b (see FIG. 5B). It is preferable that the rear protruding portion 4b has a thickness that is magnetically saturated when the short-circuit magnetic circuit is formed during braking, because short-circuit magnetism is less likely to flow and a reduction in braking force can be suppressed.
[0017]
In another eddy current type speed reducer according to the present invention, in addition to the above-described throttle portion, a pole provided with a flat front protruding portion 4c protruding beyond the permanent magnets 5, 5a, 5b on the outer peripheral side in front of rotation. Use a piece. In this eddy current type reduction gear, as shown in FIG. 6 (a), during braking, the lines of magnetic force input to the rotors 2a, 2b from the rotation front side of the pole piece 4 are caused by the action of the front protruding portions 4c. And the braking force is further improved. At this time, when the end face of the front protruding portion 4c is inclined rearward with respect to the inner peripheral surfaces of the rotors 2a and 2b as shown in FIG. 6B, the input is input to the rotors 2a and 2b. The magnetic force lines become nearly vertical, and the braking force is further improved. It is preferable that the front protruding portion 4c has a thickness that does not cause magnetic saturation when the short-circuit magnetic circuit is formed during braking, because it reaches the rotation front of the magnetic flux pole piece 4 input to the rotor and becomes more vertical.
[0018]
In the present invention, the pole piece 4 shown in FIGS. 5 and 6 may have a shape obtained by combining them. The combinations may be incorporated in one pole piece 4, or may be arranged alternately or with a regularity such as every few pieces. In any case, these effects provide both effects.
[0019]
Further, still another eddy current type speed reducer according to the present invention as shown in FIG. 7 (a) has a projection shape 4d, 4e viewed from above the main surface thereof, or FIG. 8 (a). As described above, with respect to the shape of the outer peripheral surface 4e, the pole piece 4 that is widened on the rotation rear side in the width direction orthogonal to the rotation direction of the rotor is employed. In the eddy current type reduction gear transmission according to the present invention, the lines of magnetic force from the rotor are more likely to enter the pole piece during braking, and the braking force is further improved. In this case, not only the outer peripheral surface shape as shown in FIG. 8A but also the pole piece according to the present invention which spreads on the rotation rear side as shown in FIG. preferable. Here, the main surface of the pole piece 4 refers to the surface having the largest surface area among the surfaces of the pole piece 4, and for example, in the case of a kamaboko type, a curved surface is the main surface. The term “above the main surface” refers to an axial direction that extends vertically from the center of the main surface based on this definition.
[0020]
Further, another eddy current type speed reducer according to the present invention described above, as shown in FIG. 9 (a), has a projected shape 4e, 4d viewed from above the main surface, or as shown in FIG. 10 (a). Regarding the shape of the outer peripheral surface 4e, a pole piece 4 that is widened on the rotation front side in the width direction orthogonal to the rotation direction of the rotor is adopted. In the eddy current type speed reducer according to the present invention, at the time of braking, the lines of magnetic force from the permanent magnets are more likely to enter the rotor via the pole pieces, and the braking force is further improved. In this case as well, not only the outer peripheral surface shape as shown in FIG. 10A but also the pole piece according to the present invention which spreads on the rotation front side as shown in FIG. More preferred.
[0021]
The pole piece 4 shown in FIGS. 7 to 10 may have a shape obtained by combining them in the present invention. The combinations may be incorporated in each possible pole piece 4 in a possible combination, or may be arranged alternately or with a regularity such as every few pieces. By these combinations, the respective effects are also synergized. Further, the shapes shown in FIGS. 5 and 6 may be combined with the shapes shown in FIGS. 7 to 10 in a possible combination. The combination method can be performed in the same manner as described above, and the effect is also synergistic.
[0022]
In the present invention described above, the rotation front side or the rotation rear side refers to the rotation front side or the rotation rear side from the center of the circumferential length of the pole piece. As shown in FIG. 11A, not only the rotation front end or the rotation rear end only extends in the width direction (rotation axis direction), but also the rotation 11A and 11B. On the other hand, as shown in FIG. 11B, there is also a case where the rotation front side is wider than the rotation rear side.
[0023]
In the above-described eddy current type speed reducer according to the present invention, although not shown, the present invention has a projection shape or an outer peripheral shape viewed from above the main surface extending to both the rotation front side and the rotation rear side. In the eddy current type reduction gear transmission according to the present invention employing the pole piece according to the above, the braking force is further improved by the above synergistic effect.
[0024]
【Example】
Hereinafter, a pole piece according to the present invention will be described based on an embodiment shown in FIGS.
[0025]
FIG. 1 is a view showing a first embodiment of a pole piece 4 according to the present invention. In the first embodiment, a rotation front of a pole piece 4 arranged opposite to a permanent magnet of an eddy current type speed reducer is shown. The projections 4b and 4c are formed on both the rear side and the rear side of the rotation so that the outer peripheral side protrudes into, for example, a flat plate having a thickness of 2 mm. The rotation direction of the rotor is the direction of arrow A shown in FIG. The direction of the rotation axis is also the arrow B direction.
[0026]
Then, the length of the pole piece 4 in the direction of the rotation axis is temporarily increased at an intermediate portion between the inner peripheral surface 4d and the outer peripheral surface 4e, then is shortened at the outer peripheral surface 4e, and then the outer peripheral surface 4e is reduced to the inner peripheral surface 4d. And the outer peripheral surface 4e is formed so that the shape of the outer peripheral surface 4e is widened at both ends of the pole piece 4 before and after rotation.
[0027]
In the eddy current type speed reducer according to the present invention using the pole piece 4 having such a shape, at the time of braking, the braking force is improved by the following operations.
{Circle around (1)} The density of the lines of magnetic force from the permanent magnet to the rotor via the pole piece 4 is narrowed and increased on the outer peripheral surface 4e, and when reaching the rotor, a large eddy current is generated and a large Lorentz force is obtained.
[0028]
{Circle over (2)} The density of the lines of magnetic force input to the rotor from the rear side of the rotation of the pole piece 4 is increased by the action of the protrusions 4c.
{Circle around (3)} The lines of magnetic force from the permanent magnets easily enter the rotor via the pole piece.
(4) Magnetic lines of force from the rotor easily enter the pole piece.
[0029]
Also, when not braking,
{Circle around (5)} Magnetic leakage from the permanent magnet to the rotor via the support is absorbed by the projecting portions 4b and 4c projecting in a plate shape, so that the torque loss can be reduced.
[0030]
FIG. 2 is a view showing a second embodiment of the pole piece according to the present invention. In the second embodiment shown in FIG. 2, the throttle portion 4a is not formed unlike the first embodiment. The other configuration is the same as that of the first embodiment.
[0031]
In the second embodiment having such a configuration, although there is no action of the above-mentioned (1) at the time of braking, the actions of the other (2) to (5) are the same, so that the eddy current using the conventional pole piece is used. As compared with the type reduction gear transmission, the braking torque can be improved and the loss torque can be reduced.
[0032]
The present invention is not limited to the above embodiment, and it goes without saying that even if only the claims correspond, the braking torque can be improved and the loss torque can be reduced.
[0033]
【The invention's effect】
As described above, according to the present invention,
(1) Increasing the density of lines of magnetic force from the permanent magnet to the rotor via the pole piece,
(2) The line of magnetic force input to the rotor from the rear side of the pole piece is made nearly vertical,
(3) The magnetic field lines from the permanent magnet can easily enter the rotor through the pole piece,
▲ 4 ▼ The lines of magnetic force from the rotor can easily enter the pole piece,
In particular, the braking torque during braking can be improved.
[Brief description of the drawings]
FIGS. 1A and 1B are views showing a first embodiment of a pole piece according to the present invention, wherein FIG. 1A is a perspective view, FIG. 1B is a view A in FIG. 1A, and FIG. 1C is an arrow in FIG. A view B is shown, and (d) is an arrow C view of (a).
FIGS. 2A and 2B are diagrams showing a second embodiment of the pole piece according to the present invention, wherein FIG. 2A is a perspective view, FIG. A view B is shown, and (d) is an arrow C view of (a).
FIGS. 3A and 3B are explanatory diagrams of a throttle portion which is an essential component of the pole piece according to the present invention. FIG. 3A shows a case where the throttle portion exists at an intermediate portion between the inner and outer circumferences, and FIG. And (c) is a diagram in a case where the aperture portion is an inner peripheral portion.
FIG. 4A is an explanatory view of a flow of magnetic lines of force when the pole piece according to the present invention has a constricted portion, which is an essential component of the pole piece, and FIG. 4B is a diagram of a magnetic field line of a conventional pole piece having no constricted portion. It is explanatory drawing of a flow.
FIG. 5A is an explanatory view of the flow of the lines of magnetic force during non-braking when the pole piece according to the present invention has a plate-like projection at the rear of rotation, which is an essential component of the pole piece according to the present invention; FIG. 4 is an explanatory view of the flow of magnetic force lines when a conventional pole piece having no protruding portion is not braked.
FIG. 6A is an explanatory view of a flow of lines of magnetic force at the time of braking when the pole piece according to the present invention has a plate-shaped protrusion in front of rotation, which is an essential component of the pole piece according to the present invention; FIG. 8 is an explanatory diagram of the flow of the lines of magnetic force similar to (a) when the end surface of FIG.
FIG. 7 is a view showing an example of a pole piece according to the present invention in which a projected shape as viewed from above the main surface spreads rearward in a width direction orthogonal to the rotation direction of the rotor, and FIG. , (B) is a view from the front, and (c) is a view from the left side.
8A and 8B are diagrams illustrating an example of a pole piece according to the present invention in which the outer peripheral surface shape is widened on the rotation rear side in a width direction orthogonal to the rotation direction of the rotor, where FIG. Is a view seen from the front, and (c) is a view seen from the left side.
FIG. 9 is a diagram showing an example of a pole piece according to the present invention in which a projected shape as viewed from above the main surface spreads forward in the width direction orthogonal to the rotation direction of the rotor, and FIG. , (B) is a view from the front, and (c) is a view from the left side.
10A and 10B are diagrams illustrating an example of a pole piece according to the present invention in which the outer peripheral surface shape is widened on the rotation front side in a width direction orthogonal to the rotation direction of the rotor, wherein FIG. Is a view seen from the front, and (c) is a view seen from the left side.
11A is a diagram illustrating the meaning of “spreading backward in rotation” in the present invention, and FIG. 11B is a diagram illustrating the meaning of “spread forward in rotation” in the present invention.
FIG. 12 is a cross-sectional view of a shaft slide type eddy current type reduction gear in a rotation axis direction.
FIG. 13 is a sectional view of the single-row turning type eddy current type speed reducer in the rotation axis direction.
FIG. 14 is a cross-sectional view of a double-row turning type eddy current type speed reducer in the rotation axis direction.
FIG. 15 is a sectional view of a shaft type eddy current type speed reducer using a disk type rotor in the direction of the rotation axis.
FIG. 16 is an explanatory diagram of the flow of magnetic lines of force input from a pole piece to a rotor during braking in a conventional eddy current type speed reducer.
FIG. 17 is an explanatory diagram of a magnetic circuit formed at the time of braking in a conventional eddy current type speed reducer.
[Explanation of symbols]
2a, 2b Rotor 4 Pole piece 4a Restricted portion 4b Rear protruding portion 4c Front protruding portion 4d Inner peripheral surface 4e Outer peripheral surface 5, 5a, 5b Permanent magnet

Claims (8)

A ferromagnetic plate arranged opposite to a permanent magnet of the eddy current type reduction gear,
Between the inner and outer peripheries of the ferromagnetic plate, an outer peripheral portion, an aperture portion having a cross-sectional area smaller than the area of the inner peripheral surface or the outer peripheral surface is provided at any of the inner peripheral portion,
A ferromagnetic plate having a front protruding portion or a rear protruding portion in which a front or rear outer peripheral side projects in a flat plate shape in a rotation progress direction of a member that internally generates an eddy current during braking. A ferromagnetic plate arranged opposite to a permanent magnet of the eddy current type reduction gear,
Between the inner and outer peripheries of the ferromagnetic plate, an outer peripheral portion, an aperture portion having a cross-sectional area smaller than the area of the inner peripheral surface or the outer peripheral surface is provided at any of the inner peripheral portion,
The width of the projected shape or the outer peripheral surface of the ferromagnetic plate viewed from above the main surface thereof, which is orthogonal to the rotation direction of the member that internally generates the eddy current at the time of braking, is the front side or the rear side in the rotation traveling direction. A ferromagnetic plate characterized by being spread out in. A ferromagnetic plate arranged opposite to a permanent magnet of the eddy current type reduction gear,
The ferromagnetic plate has a front protruding portion or a rear protruding portion in which a front or rear outer side protrudes in a flat plate shape toward a traveling direction of a member that generates an eddy current inside during braking. The ferromagnetic plate according to claim 2. A ferromagnetic plate arranged opposite to a permanent magnet of the eddy current type reduction gear,
A front or rear protruding portion in which a front or rear outer circumferential side protrudes in a flat plate shape toward a traveling direction of a member that internally generates an eddy current during braking,
The width of the projected shape or the outer peripheral surface of the ferromagnetic plate viewed from above the main surface thereof, which is orthogonal to the rotation direction of the member that internally generates the eddy current at the time of braking, is the front side or the rear side in the rotation traveling direction. A ferromagnetic plate characterized by being spread out in. The ferromagnetic plate having a forward protrusion,
The ferromagnetic material according to any one of claims 1, 3 and 4, wherein a front end surface of the front protruding portion is inclined rearward with respect to an inner peripheral surface of the member that generates the eddy current therein. Board. The ferromagnetic plate according to any one of claims 1 to 3, wherein the thickness of the rear protrusion is a thickness that is magnetically saturated when a short-circuit magnetic circuit is formed during braking. 7. The ferromagnetic plate according to claim 1, wherein the thickness of the front protrusion is a thickness that does not cause magnetic saturation when a short-circuit magnetic circuit is formed during braking. An eddy current type speed reducer comprising at least the ferromagnetic plate according to claim 1.

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