JP2001224160A - Eddy current type deceleration apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve magnetic circuit efficiency and remove extra processes. SOLUTION: This eddy current type deceleration apparatus comprises a rotor 1 mounted integrally to a rotating shaft, a group of permanent magnets 3 supported counterposing this rotor 1 and allocated to keep a constant interval to a support ring 2, made of ferro-magnetic material to provide mutually reverse direction of magnetic poles along the circumference of rotor 1, a group of switch plates 4 of a ferromagnetic material provided between the permanent magnet group 3 and rotor 1 via the interval equal to the permanent magnet 3 of the group of permanent magnets 3 and a nonmagnetic support body 5 provided between each switch plate 4 of the group of switch plates 4. A bearing 12, supporting the support ring 2 for ensuring the revolution in the predetermined angle, is provided between the support body 5 and the external circumference of the support ring 2. Thereby, efficiency of magnetic circuit is improved in comparison with the existing structure. Moreover, such improvement can be realized using a low-price surface treatment, and extra process can also be removed for improvement of accuracy.

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 of using a foot brake to prevent abnormal wear of a lining and a fade phenomenon. At the same time, in order to reduce 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. Recently, many types use a permanent magnet that does not need to be energized during braking. 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. 11-228267 is integrally mounted on a rotating shaft as shown in FIG. A rotor 1 and a ferromagnetic support ring 2 which are supported opposite to the rotor 1 and are spaced apart from each other along a circumferential direction of the rotor 1 so that the magnetic poles are opposite to each other. A group of permanent magnets 3 and a group of ferromagnetic switch plates 4 interposed between the group of permanent magnets 3 and the rotor 1 at the same intervals as the respective permanent magnets 3 of the group of permanent magnets 3 And a non-magnetic support member 5 interposed between the switch plates 4 of the group of switch plates 4, and a braking unit in which the permanent magnet 3 overlaps the switch plate 4 via the support ring 2 by the driving unit 6. ON or one permanent magnet 3 is adjacent Be one or no braking OFF the overlapping halves across the switch plate 4 is obtained by defining the thickness and spacing of the switch plate 4 so as to maintain an optimum relationship. In FIG. 3, reference numeral 1 a denotes a cylindrical portion of the rotor 1, 1 b denotes a cooling fin of the rotor 1, 7 is interposed between the inner peripheral surface side and one side wall side of the support ring 2 and the support 5, respectively.
3 shows a bearing that rotatably supports the support ring 2.

[0004] The applicant of the present invention is disclosed in Japanese Patent Application No. 11-228267.
An eddy current type speed reducer of the single-row turning type proposed in Japanese Patent Application Laid-Open No. 4-12659 discloses a rotor 1 provided on a rotating shaft, as shown in FIG. A fixed support ring 9 having a group of permanent magnets 8 which are supported from the fixed side in opposition to each other and in which N poles and S poles are alternately arranged at predetermined intervals along the circumferential direction, and the same as the fixed support ring 9 A movable support ring 11 having a group of permanent magnets 10 and rotatable with respect to the fixed support ring 9, and a movable support ring 11 interposed between the rotor 1 and the group of permanent magnets 8 and 10. A plurality of ferromagnetic switch plates 4 extending from above each permanent magnet 8 to above the movable support ring 11
And the number of parts can be greatly reduced as compared with a double-row turning type eddy current type reduction gear provided with a non-magnetic support member 5 interposed between the switch plates 4. And the cost can be reduced, and the turning angle of the permanent magnet is halved, so that the cylinder can be downsized and the air consumption can be reduced.

[0005]

By the way, the ambient temperature of the eddy current type reduction gear at the time of starting the vehicle is in a temperature range of -20 to -30.degree.
The temperature during use of the eddy current type speed reducer during traveling increases to 70 to 90 ° C. due to heating by heat transfer from the rotor 1 located on the outer peripheral portion.

On the other hand, in the eddy current type speed reducer described above, the support 5 is generally made of an aluminum alloy casting or the like in order to reduce the weight, secure non-magnetism, and secure heat radiation. , High coefficient of thermal expansion. Therefore, the dimensional change of the support body 5 due to temperature change is remarkable with respect to the steel bearing 7 and the support ring 2.

For this reason, the gap ε ₁ between the switch plate 4 and the permanent magnet 3 is determined so that the switch plate 4 and the permanent magnet 3 do not interfere with each other even at the lowest temperature when the vehicle is started. Also, the gap ε ₂ between the support 5 and the bearing 7 is determined to a value that can secure an appropriate gap as the bearing 7 at the maximum temperature when the eddy current type reduction gear is used during traveling.

However, at low temperatures, the gap ε ₂ increases due to the difference in the coefficient of thermal expansion between the bearing 7 and the support 5, and it is necessary to take this increase into account when determining the gap ε ₁ . In the conventional structure in which the support ring 2 is supported by the bearing 7 provided on the inner peripheral surface side of the support ring 2 and the inner peripheral surface side of the support 5, the gap ε ₁ becomes unnecessarily large. . The size of the gap epsilon ₁ is made to a decrease in the magnetic circuit efficiency becomes reluctance in the magnetic circuit, so that the amount of expensive permanent magnet 3 is increased.

In addition, high precision is required for the surface accuracy of the gaps ε ₁ and ε _{2 in} the support 5, and the sliding surface of the support 5 opposed to the bearing 7 is hardened to ensure durability. It is necessary to take measures such as the above, which is also a factor that increases the manufacturing cost.

The present invention has been made in view of the above-mentioned conventional problems, and has been made in consideration of a gap ε between a switch plate and a permanent magnet.
Minimum clearance ε without increasing ₁ more than necessary
With _1, thereby improving the magnetic circuit efficiency, and its object is to provide an eddy current type reduction gear can be omitted even extra processing, such as for improved accuracy.

[0011]

In order to achieve the above-mentioned object, an eddy current type speed reducer according to the present invention comprises a bearing for supporting a support ring so as to be able to turn at a predetermined angle with the support body. It is arranged between the outer peripheral parts of the ring.
Then, by doing so, as a switch plate with a gap epsilon ₁ minimum necessary size of between permanent magnets, the can be improved magnetic circuit efficiency, extra processing, such as for improved accuracy Can also be omitted.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An eddy current type speed reducer according to the present invention has a rotor integrally mounted on a rotating shaft and a rotor supported opposite to the rotor and having magnetic poles oriented along the circumferential direction of the rotor. A permanent magnet group arranged at a fixed interval on a ferromagnetic support ring so as to be in the opposite direction, and between the permanent magnet group and the rotor, the same as each permanent magnet of the permanent magnet group. An eddy current type reduction gear comprising: a ferromagnetic switch plate group interposed at intervals and a non-magnetic support member interposed between the switch plates of the switch plate group. A bearing for rotatably supporting the ring at a predetermined angle is provided between the support and the outer peripheral portion of the support ring.

In the eddy current type speed reducer of the present invention, since the bearing for supporting the support ring so as to be able to pivot at a predetermined angle is provided between the support and the outer peripheral portion of the support ring, the support ring is supported. , as compared to the inner peripheral surface side of the support ring and the inner peripheral surface of the conventional has been performed by interposed the bearing side structure of the support, the permanent magnet and the switch plates gap epsilon ₁ and the support and between the bearings it is as shown substantially dimensional changes of the same shape and size gap epsilon ₂ is a temperature change, can be a minimum size without increasing more than necessary clearance epsilon _1. In addition, since the sliding surface of the bearing is not supported by the conventional aluminum alloy casting support, but by a steel support ring, it can be handled with inexpensive surface treatment. Since a product can be obtained, extra processing for improving accuracy or the like can be omitted.

In the eddy current type speed reducer of the present invention, when the switch plate and the permanent magnet overlap with each other due to the turning movement of the support ring (permanent magnet group), the support ring, the adjacent permanent magnet and the adjacent switch plate, and the rotor A magnetic circuit is formed in the cylindrical portion, so-called braking ON state occurs. When the cylindrical portion of the rotating rotor crosses the magnetic field from the permanent magnet, the eddy current generated in the cylindrical portion of the rotor and the action of the magnetic field cause the cylindrical portion of the rotor to rotate. Generates a braking torque.

Further, from the above-mentioned brake ON position, when one permanent magnet is in a brake OFF state in which the two permanent magnets overlap each other over an adjacent switch plate, a support ring,
A short-circuit magnetic circuit is formed by the adjacent permanent magnets and the switch plate straddling these permanent magnets, and the magnetic field hardly acts on the cylindrical portion of the rotor, so that the braking force becomes extremely small.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An eddy current type speed reducer according to the present invention will be described below with reference to the embodiments shown in FIGS. 1 and 2, the same reference numerals as those in FIGS. 3 and 4 denote the same or corresponding parts, and a detailed description thereof will be omitted. FIG. 1 is an enlarged explanatory view showing a main part of an eddy current type reduction gear of the present invention, and FIG. 2 is a view similar to FIG. 1 showing another embodiment of the eddy current type reduction gear of the present invention.

FIGS. 1 and 2 show an eddy current type speed reducer according to the present invention, which is similar to the one proposed by the present applicant described in FIG. 3 in Japanese Patent Application No. 11-228267. A rotor 1 integrally attached to a shaft;
And a group of permanent magnets 3 arranged at regular intervals on a ferromagnetic support ring 2 so that the directions of the magnetic poles are opposite to each other along the circumferential direction of the rotor 1. A group of four ferromagnetic switch plates interposed between the group of permanent magnets 3 and the rotor 1 at the same intervals as the respective permanent magnets 3 of the group of permanent magnets 3, and a group of switch plates 4 of this type The structure has a non-magnetic support member 5 interposed between the switch plates 4.

In the eddy current type speed reducer of the present invention, in the above-mentioned structure, the support ring 2 is extended on both sides of the permanent magnet 3 and the support 5 is provided on a portion facing the outer peripheral side of the extension 2a. By projecting, a bearing 12 such as a slide bearing is interposed between the outer peripheral portion of the projecting portion 2a on both sides and the projecting portion 5a of the support 5 so that the support ring 2 can be turned by a predetermined angle. It is intended to be supported.

The overhang 2a may have the same shape on the left and right as shown in FIG. 1, but may have different shapes on the left and right as shown in FIG. When the left and right shapes are different as shown in FIG. 2, the weight of the support ring 2 can be reduced, so that the overall weight can be reduced.

In the eddy current type speed reducer shown in FIGS. 1 and 2, when the switch plate 4 and the permanent magnet 3 overlap with each other by turning the support ring 2 by the drive unit 6, the support ring 2 When a magnetic circuit is formed by the adjacent permanent magnet 3 and the adjacent switch plate 4 and the cylindrical portion 1a of the rotor 1, a so-called braking ON state is provided, and when the rotating cylindrical portion 1a crosses the magnetic field from the permanent magnet 3, By the action of the eddy current and the magnetic field generated in the cylindrical portion 1a, a braking torque is generated in the cylindrical portion 1a.

Further, from the braking ON position, the support ring 2 is rotated to rotate the three rows of permanent magnets by a half pitch of the magnets. In this state, one permanent magnet 3 overlaps the adjacent switch plate 4 by half, and a short-circuit magnetic circuit is formed by the support ring 2, the adjacent permanent magnet 3 and the switch plate 4. As a result, a so-called braking OFF state is set.

Since the eddy current type speed reducer of the present invention employs the above-described structure, the gap ε ₁ between the permanent magnet 3 and the switch plate 4 and the gap ε ₂ between the support 5 and the bearing 12 change with temperature. Of the same size and size. Therefore, when determining the gap ε ₁ between the permanent magnet 3 and the switch plate 4, it is not necessary to consider an increase in the gap ε ₂ between the support 5 and the bearing 12, and the gap ε ₁ is made larger than necessary. The size of the magnetic circuit can be reduced to the minimum necessary without increasing the efficiency of the magnetic circuit.

In the eddy current type speed reducer of the present invention, the sliding surface of the bearing is not covered by the conventional aluminum alloy casting support 5 but by the steel support ring 2.
In addition to being able to cope with an inexpensive surface treatment, it is also possible to easily obtain a high-precision processing accuracy, so that extra processing for improving the accuracy can be omitted.

In the embodiment shown in FIGS. 1 and 2, the pole piece is omitted, but the pole piece may be attached to the outer periphery of the permanent magnet 3.

[0025]

As described above, according to the eddy current speed reducer of the present invention, the support of the support ring is provided by the bearing provided on the inner peripheral surface side of the support ring and the inner peripheral surface side of the support. compared with the conventional structure that has been done, so that a gap epsilon ₂ between the gap epsilon ₁ and the support and the bearing of the permanent magnet and the switch plates exhibit substantially dimensional changes of the same shape and size with respect to the temperature change from becoming it can be the size of the minimum required clearance epsilon _1. Therefore, as compared with the conventional structure in which bearings are provided on the inner peripheral surface side of the support ring and the inner peripheral surface side of the support,
Magnetic circuit efficiency is improved.

Further, according to the eddy current type speed reducer of the present invention, the sliding surface of the bearing is not a conventional aluminum alloy casting support but a steel support ring. It can be handled by surface treatment. Also, as for the processing accuracy, a high-precision one can be easily obtained, so that extra processing for improving the accuracy can be omitted.

[Brief description of the drawings]

FIG. 1 is an enlarged explanatory view showing a main part of an eddy current type speed reducer of the present invention.

FIG. 2 is a view similar to FIG. 1, showing another embodiment of the eddy current type speed reducer of the present invention.

FIG. 3 is an explanatory view showing an enlarged main part of a single-row turning type eddy current type speed reducer proposed by the present applicant in Japanese Patent Application No. 11-228267.

FIG. 4 is a side view of an eddy current type reduction gear proposed in Japanese Patent Application Laid-Open No. 4-12659, in which an upper half is shown in cross section.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotor 2 Support ring 2a Overhang part 3 Permanent magnet 4 Switch plate 5 Support body 5a Projection part 12 Bearing

Claims (1)

[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. And a ferromagnetic material interposed between the permanent magnet group and the rotor at the same interval as each permanent magnet of the permanent magnet group. In the eddy current type speed reducer provided with a switch plate group and a non-magnetic support member interposed between the switch plates of the switch plate group, a bearing for supporting the support ring so as to be able to pivot at a predetermined angle is provided. An eddy current type reduction gear, which is interposed between an outer peripheral portion of the support and a support ring.