JP2004096935A - Eddy current type reduction gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an eddy current type reduction gear which can reduce in weight without decreasing a braking performance. <P>SOLUTION: In the eddy current type reduction gear 1, a support member 3 made of a nonmagnetic material is disposed oppositely to a rotatable rotor 2, a plurality of permanent magnets 4 are provided at the rotor 2 side of the member 3 in such a manner that poles are directed in a circumferential direction and opposed poles are provided at the same polarity at an interval in the circumferential direction, and magnetic members 5 are provided between the adjacent magnets 4. Further, holes 12 for lightening are formed at the side radially separate from the rotor 2 at circumferential intermediate positions of the members 5. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to an eddy current type speed reducer that applies deceleration braking to a rotating body such as a drive shaft.
[0002]
[Prior art]
2. Description of the Related Art As an eddy current type speed reducer using a permanent magnet, there is known an eddy current type speed reducer described in Patent Literature 1 of the present applicant.
[0003]
As shown in FIG. 19, the eddy current type speed reducer 50 includes a rotor 51 coupled to a rotating shaft (not shown), and a yoke 52 provided on the inner peripheral side of the rotor 51 so as to face the rotor 51 and made of a non-magnetic material. A permanent magnet 53 is provided between the permanent magnets 53 adjacent to each other, and a permanent magnet 53 is provided in the circumferential direction so that the magnetic poles are directed in the circumferential direction on the outer periphery of the yoke 52 and the magnetic poles facing each other are made the same. It is provided with a magnetic member 54 made of a magnetic material and a cover 55 provided on the outer peripheral side of the permanent magnet 53 and made of a non-magnetic material.
[0004]
The magnetic member 54 is configured to form a pole piece, and allows a magnetic flux from a magnetic pole facing in the circumferential direction to enter the rotor 51 facing in the radial direction.
[0005]
The eddy current type reduction gear 50 causes the magnetic flux emitted from the permanent magnet 53 to reach the rotor 51 via the magnetic member 54 and returns to the permanent magnet 53 only via the other magnetic member 54. Unlike the eddy current type speed reducer (not shown) of the directing type, the magnetic flux does not flow through the yoke 52, and the excellent performance that the entire magnetic flux can be effectively used for braking is exhibited.
[0006]
[Patent Document 1]
JP-A-2000-184690 (page 3, FIG. 1)
[0007]
[Problems to be solved by the invention]
However, since it is a completely new type of eddy current type speed reducer, it was not possible to reduce the weight in a blind manner considering the effect on the performance, and there is room for improvement in the weight reduction.
[0008]
Therefore, an object of the present invention is to solve the above-described problems and to provide an eddy current type speed reducer that can be reduced in weight without reducing braking performance.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a support member made of a non-magnetic material is arranged facing a rotatable rotor, and a plurality of permanent magnets are respectively directed in a circumferential direction on a rotor side of the support member, and In an eddy current type speed reducer in which magnetic poles facing each other are provided at intervals in the circumferential direction so as to have the same polarity, and magnetic members are provided between these adjacent permanent magnets, at a circumferential intermediate position of the magnetic member. In addition, a hole for reducing the weight is formed on the side radially separated from the rotor.
[0010]
Since the holes do not interfere with the magnetism flowing in the magnetic member, the weight can be reduced without increasing the magnetic resistance and without reducing the braking performance.
[0011]
Further, a groove for reducing the weight may be formed at a circumferentially intermediate position of the magnetic member and on a surface radially separated from the rotor.
[0012]
Then, a support member made of a non-magnetic material is arranged facing the rotatable rotor, and a plurality of permanent magnets are directed to the rotor side of the support member in the circumferential direction and the facing magnetic poles are made to be the same. In the eddy current type reduction gear transmission provided with a magnetic member between these adjacent permanent magnets at an intermediate position in the circumferential direction of the magnetic member and radially separated from the rotor, A groove for reducing the weight may be formed on the surface on the side to be formed.
[0013]
Further, the hole, the groove, or both the hole and the groove may be formed so as to extend in the axial direction.
[0014]
The magnetic member may have a plurality of holes or grooves or both holes and grooves.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0016]
FIG. 1 is a front cross-sectional view of the eddy current type speed reducer according to the present embodiment as viewed from the shaft end side of a rotor. FIG. 2 is a cross-sectional view of the eddy current type speed reducer cut radially along the axis of the rotor.
[0017]
As shown in FIGS. 1 and 2, an eddy current type speed reducer 1 is mounted on a rotating shaft (not shown) of a power transmission system such as a drive shaft of a vehicle, and is a drum-shaped rotor 2 which rotates integrally with the rotating shaft. And a yoke 3 as a support member provided movably in the axial direction on the inner peripheral side of the rotor 2, and a plurality of yokes 3 provided on the outer peripheral side (rotor 2 side) of the yoke 3 at predetermined intervals (equal pitch) in the circumferential direction. And a magnetic member 5 provided between adjacent permanent magnets 4.
[0018]
The rotor 2 is formed of a magnetic material such as iron that transmits magnetism, and has an inner circumference formed in a perfect circle so as to be always close to the permanent magnet 4 at a fixed minute interval. A plurality of heat dissipating fins 6 are formed on the outer periphery of the rotor 2.
[0019]
The yoke 3 is formed of a nonmagnetic material in a cylindrical shape, and has a length in the axial direction shorter than that of the rotor 2. The yoke 3 circumscribes a guide 7 formed in a cylindrical shape, is supported movably in the axial direction, and is attached to a cylinder rod 9 of an air cylinder 8 that expands and contracts in the axial direction. The yoke 3 is moved into a braking position where the air cylinder 8 extends into the rotor 2 and the outer peripheral surface 11 of the magnetic member 5 faces the inner peripheral surface 10 of the rotor 2 when the air cylinder 8 expands, and the air cylinder 8 retracts. , The magnetic member 5 is moved to a non-braking position where the magnetic member 5 is separated from the rotor 2 in the axial direction.
[0020]
The permanent magnets 4 all have the same shape and the same magnetic force, and are alternately reversed so that the magnetic poles are directed in the circumferential direction and the magnetic poles facing each other have the same polarity (for example, the N poles face each other). Are located.
[0021]
The magnetic member 5 is formed by forming a magnetic material (for example, a soft magnetic material: an iron block material, a laminated electromagnetic steel plate, or the like) in a block shape, and all have the same shape. The magnetic member 5 is formed so that the length in the circumferential direction is greater than the thickness in the radial direction, and when attached to the yoke 3, the outer peripheral surface 11 is attached to the inner peripheral surface 10 of the rotor 2 by a predetermined minute size. It is formed in an arc shape so as to be spaced apart.
[0022]
One hole 12 for reducing the weight is formed on the inner peripheral side of the magnetic member 5 in the circumferential direction and radially separated from the rotor 2. The hole 12 is formed to extend in the axial direction, and penetrates the magnetic member 5. The hole 12 is formed in a circular shape that is easy to process and has a diameter of 7 mm (about 5.7% of the axial end surface area (including the end surface area of the hole) of the magnetic member 5).
[0023]
Next, the operation of the present embodiment will be described.
[0024]
When the yoke 3 is moved into the rotor 2 by extending the air cylinder 8, the outer peripheral surface 11 of the magnetic member 5 is opposed to the inner peripheral surface 10 of the rotor 2 at a small interval. The magnetism emitted from the permanent magnet 4 is transmitted to the rotor 2 through the magnetic member 5 and returns to the permanent magnet 4 as a magnetic source via another magnetic member 5 adjacent in the circumferential direction. That is, the magnetic circuit 13 is configured between the permanent magnet 4 and the rotor 2. Then, an interaction between an eddy current generated by the rotation of the rotor 2 with respect to the permanent magnet 4 and a magnetic field from the permanent magnet 4 generates a braking force.
[0025]
At this time, since the hole 12 of the magnetic member 5 is formed at an intermediate position in the circumferential direction and at an inner circumferential side which is radially separated from the rotor 2, it is necessary to increase the magnetic resistance by interfering with the magnetic flux. There is no effect on braking performance.
[0026]
When the air cylinder 8 is retracted, the yoke 3 is moved out of the rotor 2, and the magnetism from the permanent magnet 4 stops flowing to the rotor 2.
[0027]
As described above, since the hole 12 for reducing the weight is formed at the circumferentially intermediate position of the magnetic member 5 and on the side radially separated from the rotor 2, the eddy current type reduction gear 1 can be reduced in weight while maintaining the braking performance. Can be Then, the air cylinder 8 for moving the yoke 3 in the axial direction together with the magnetic member 5 can be replaced with a small and lightweight one.
[0028]
In this embodiment, the magnetic member 5 is formed so that the φ7 mm round hole 12 is formed so as to penetrate in the axial direction. However, the present invention is not limited to this.
[0029]
As shown in FIG. 3, it has been confirmed that it is practical to form a round hole 21 of φ15 mm (about 26% of the axial end surface area of the magnetic member) in the magnetic member 20 instead of the round hole 12 of φ7 mm. did it.
[0030]
Specifically, when the hole for reducing the weight is not formed in the magnetic member, when the round hole 12 of 7 mm is formed, and when the round hole 21 of 15 mm is formed, the rotation speed of the rotor 2 is 1000 rpm, An electromagnetic field analysis of the braking torque at 2000 rpm and 3000 rpm was performed.
[0031]
The result was the torque curve shown in FIG. When there is a φ7 mm round hole 12, the braking torque at each rotation speed (open triangle in the figure) is the same as when there is no hole (black circle in the figure), and the weight can be reduced without deteriorating the braking performance. Was confirmed. In the case where there is a round hole 21 of φ15 mm (open circles in the figure), a slight decrease in torque was observed at 1000 rpm (low rotation), but there was no decrease in torque at 2000 rpm or more (middle and high rotation). It was confirmed that the weight can be reduced while maintaining the braking performance.
[0032]
In addition, electromagnetic field analysis was performed on the influence of the size of the hole diameter on the braking torque when the rotation speed of the rotor 2 was 1000 rpm, 2000 rpm, and 3000 rpm.
[0033]
The results are as shown in FIG. No reduction in braking torque is observed at any of 1000 rpm, 2000 rpm, and 3000 rpm until the hole diameter is φ0 to 7 mm, and the braking torque at 1000 rpm is inversely proportional to the size of the hole diameter even when the hole diameter exceeds φ7 mm. It was confirmed that the braking torque could be almost maintained with a slight decrease. From these results, it is expected that the maximum value of the hole diameter is about 15 mm + 2 to 3 mm in practical use. That is, it has been found that a round hole up to φ18 mm (about 38% of the axial end surface area of the magnetic member) can be formed in the magnetic member. However, if a decrease in performance torque at low rotation becomes a problem, a hole smaller than φ15 mm may be formed.
[0034]
4, 5, and 6, the shape of the holes 22, 23, and 24 may be triangular in cross section, rectangular, or trapezoidal. Then, as shown in FIG. 7, a hole 25 having a shape combining a circle and a rectangle or a hole (not shown) having a shape combining other shapes may be used. Further, the holes 12, 21, 22, 23, 24, 25 described above may not penetrate the magnetic members 5, 20, 26, 27, 28, 29. Then, a plurality of holes 31 and 32 may be formed in the magnetic member 30 as shown in FIG. However, in order to prevent interference with the magnetic flux, it is preferable to determine the shape of the hole and the like so that the hole is separated from the permanent magnet 4 as it approaches the rotor 2 at a position relatively close to the rotor 2.
[0035]
Further, as shown in FIG. 9, a groove 42 for reducing the weight is formed in the circumferential surface 41 at the intermediate position in the circumferential direction of the magnetic member 40 and on the side (inner circumferential side) radially separated from the rotor 2. May be. The groove 42 is formed in a triangular cross-section that narrows radially outward (toward the rotor 2). The groove 42 may be a groove 43 having a semicircular cross section or a rectangular groove 44 as shown in FIGS. 10 and 11, and may be formed in another shape. Further, as shown in FIG. 12, a plurality of grooves 46 may be formed in the magnetic member 45, or both the grooves 46 and the holes 47 may be formed. In this case, a plurality of grooves 46 and a plurality of holes 47 may be respectively formed, or only one of the plurality of grooves 46 and a plurality of holes 47 may be formed.
[0036]
Further, in the present embodiment, the magnetic member 5 is directly opposed to the rotor 2 at the time of braking, but the present invention is not limited to this. As shown in FIGS. 15 and 16, it is more preferable that the magnetic member 5 and the permanent magnet 4 are surrounded by the casing 60 together with the yoke 3, and the magnetic member 5 is opposed to the rotor 2 through the casing 60. The casing 60 may be formed of a non-magnetic material such as aluminum. The casing 60 may be formed to be long in the axial direction so as to allow the yoke 3 to move in the axial direction, and may be provided in the air cylinder 8. Surrounding the magnetic member 5, the permanent magnet 4, and the yoke 3 with the casing 60 in this way can prevent dust and water from entering the inside of the apparatus, so that the durability can be improved and is practical.
[0037]
Further, the casing 60 is not limited to this, and as shown in FIGS. 17 and 18, a part (a part 62 sandwiched between the rotor 2 and the magnetic member 5) is formed of a magnetic material such as low carbon steel. It is good also as casing 61 made. In addition, it goes without saying that all the eddy current type speed reducers shown in FIGS. 3 to 12 may include the above-described casing 60 or casing 61.
[0038]
【The invention's effect】
In short, according to the present invention, the following excellent effects can be obtained.
(1) The eddy current type reduction gear can be reduced in weight without deteriorating the braking performance.
[Brief description of the drawings]
FIG. 1 is a front sectional view of an eddy current type reduction gear transmission showing a preferred embodiment of the present invention.
FIG. 2 is a sectional view taken along line II-II of FIG.
FIG. 3 is a front sectional view of an eddy current type reduction gear transmission showing another embodiment.
FIG. 4 is a front sectional view of an eddy current type reduction gear transmission according to another embodiment.
FIG. 5 is a front sectional view of an eddy current type speed reducer showing another embodiment.
FIG. 6 is a front sectional view of an eddy current type reduction gear transmission according to another embodiment.
FIG. 7 is a front sectional view of an eddy current type reduction gear transmission showing another embodiment.
FIG. 8 is a front sectional view of an eddy current type speed reducer according to another embodiment.
FIG. 9 is a front sectional view of an eddy current type reduction gear transmission showing another embodiment.
FIG. 10 is a front sectional view of an eddy current type reduction gear transmission according to another embodiment.
FIG. 11 is a front sectional view of an eddy current type speed reducer according to another embodiment.
FIG. 12 is a front sectional view of an eddy current type reduction gear transmission according to another embodiment.
FIG. 13 is a diagram showing the relationship between the rotational speed of the rotor and the braking torque when the magnetic member has no hole, when it has a hole of φ7 mm, and when it has a hole of φ15 mm.
FIG. 14 is a diagram showing the relationship between the hole diameter and the braking torque when the rotation speed of the rotor is 1000 rpm, 2000 rpm, and 3000 rpm.
FIG. 15 is a front sectional view of an eddy current type reduction gear transmission according to another embodiment.
FIG. 16 is a sectional view taken along line XVI-XVI in FIG. 15;
FIG. 17 is a front sectional view of an eddy current type speed reducer according to another embodiment.
18 is a sectional view taken along the line XVIII-XVIII in FIG.
FIG. 19 is a front sectional view of a conventional eddy current type speed reducer.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Eddy current type reduction gear 2 Rotor 3 Yoke (support member)
4 permanent magnet 5 magnetic member 12 hole 42 groove

Claims (5)

A support member made of a non-magnetic material is arranged facing the rotatable rotor, and a plurality of permanent magnets are arranged on the rotor side of the support member such that the magnetic poles are oriented in the circumferential direction and the magnetic poles facing each other have the same polarity. In an eddy current reduction device provided with a magnetic member between these adjacent permanent magnets, the magnetic member is provided at an intermediate position in a circumferential direction of the magnetic member and is radially separated from the rotor. An eddy current type speed reducer, wherein a hole for reducing the weight is formed on the side. 2. The eddy current type reduction gear according to claim 1, wherein a groove for reducing the weight is formed on a surface at a radially intermediate position of the magnetic member and radially separated from the rotor. A support member made of a non-magnetic material is arranged facing the rotatable rotor, and a plurality of permanent magnets are arranged on the rotor side of the support member such that the magnetic poles are oriented in the circumferential direction and the magnetic poles facing each other have the same polarity. In an eddy current reduction device provided with a magnetic member between these adjacent permanent magnets, the magnetic member is provided at an intermediate position in a circumferential direction of the magnetic member and is radially separated from the rotor. An eddy current type speed reducer, wherein a groove for reducing weight is formed on a side surface. The eddy current reduction device according to any one of claims 1 to 3, wherein the hole, the groove, or both the hole and the groove are formed to extend in an axial direction. The eddy current type reduction gear according to any one of claims 1 to 4, wherein a plurality of the holes, the grooves, or both the holes and the grooves are formed in the magnetic member.

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