JP3966259B2 - Eddy current reducer - Google Patents

Description

  The present invention relates to an eddy current type reduction gear mounted on a vehicle such as an automobile for assisting a main brake, and in particular, a magnetic pole surface of a magnetic source such as a magnet is brought close to and separated from a braking disk attached to a rotating shaft of the vehicle. The present invention relates to an eddy current type reduction device.

For example, as an eddy current type speed reducer, a stationary magnet support ring is arranged opposite to a braking disk attached to a rotating shaft of a vehicle, and a plurality of electromagnets are attached to the magnet support ring at predetermined intervals in the circumferential direction. There is a disk-type eddy current type speed reducer that generates an eddy current in a braking disk by energizing the motor and generates a braking force on a rotating shaft.
JP 2002-291222 A

In recent years, functions required for an eddy current type speed reducer have diversified, and one of them is a simplified structure while ensuring the durability of the apparatus.
This requirement is the same for the disk-type eddy current type speed reducer. In this case, instead of turning on / off the electromagnet, the permanent magnet is moved closer to and away from the brake disk. A simple structure can be achieved by adopting a structure.

  Now, for the purpose of simplifying the structure, for example, an eddy current type speed reducer of the type in which the magnetic pole surface of the permanent magnet is brought close to and separated from the main surface of the braking disk is attached to the rotary shaft 1 as shown in FIG. At a position facing the main surface of the brake disk 2, for example, a ring-shaped holding member 6 in which a group of permanent magnets 5 in which N poles and S poles are alternately arranged in the circumferential direction is attached to the side surface via a cover 8 is arranged. The holding member 6 is structured such that the inside of the case 3 can be advanced and retracted by the actuator 7 from a proximity position where the permanent magnet 5 group completely faces the control disk main surface to a separation position where the permanent magnet 5 group completely separates.

  Here, the braking disk main surface refers to a flat surface that faces a permanent magnet or the like in a disk-shaped or ring-shaped mainly flat plate. The magnetic force source means a permanent magnet, an electromagnet, or a combination of them that can generate a magnetic field spontaneously. Further, the magnetic pole surface refers to one end surface of the magnetic source such that the magnetic flux emitted from the magnetic source includes a component that crosses in the vertical direction.

  In such an eddy current type speed reducer, the braking disk 2 is formed of a ferromagnetic material, and the surface on the left side of FIG. 9 functions as a braking surface in FIG. The case 3 is made of a nonmagnetic material or a soft magnetic material, and is formed of a material such as aluminum, an aluminum alloy, carbon steel, cast iron, or stainless steel. The holding member 6 is formed of a ferromagnetic material. The cover 8 is made of a ring-shaped flat plate and is made of a nonmagnetic material or a soft magnetic material. Examples of the cover material include aluminum, an aluminum alloy, carbon steel, cast iron, and stainless steel. These may be used alone or in a stacked manner.

  In the eddy current type speed reducer, the brake is turned on when the permanent magnet is brought close to the brake disk, and the brake is turned off when the permanent magnet is separated from the brake disk. In the braking ON state, the ferromagnetic braking disk that rotates the magnetic flux generated by the permanent magnet crosses, so an eddy current is generated in the braking disk, and the braking force is applied to the braking disk by the interaction between the eddy current and the magnetic flux. appear.

  At this time, Joule heat is generated near the surface of the braking disk on the side facing the permanent magnet, so that the temperature of the braking disk rises. When the temperature of the brake disk rises, the cover adjacent to the brake disk is heated by heat conduction using radiation and air as a medium.

  On the other hand, in the brake OFF state, since no magnetic flux acts on the brake disk, the brake disk does not generate heat and the cover is not heated. Therefore, when braking ON / braking OFF is repeated, the temperature of the braking disk fluctuates, and accordingly, the cover is repeatedly heated / cooled and a thermal cycle is loaded.

  Therefore, in an eddy current type speed reducer in which the permanent magnet is brought close to and away from the braking disk, in order to improve the braking efficiency, the distance between the permanent magnet and the surface of the braking disk is shortened, and the magnetic flux generated by the permanent magnet is reduced. It is necessary to act on the brake disc without damping as much as possible. Therefore, it is necessary to bring the brake disk as close to the cover as possible. However, if the distance between the brake disk and the cover is shortened, the amount of heat transfer from the disk to the cover increases, and the temperature of the cover increases.

  However, the attachment of the cover 8 to the case 3 in this type of eddy current type reduction gear is only to fix the cover 8 to the case 3 by screwing, caulking, press-fitting, adhesion, welding, etc. No consideration was given to the durability.

  Accordingly, the problem to be solved by the present invention is that in the eddy current type speed reducer of the type in which the magnetic pole surface of a magnetic source such as a permanent magnet is brought close to and away from the main surface of the braking disk, the magnetic source (that is, the magnet) is changed. The durability of the covering cover was not considered at all.

The main feature of the present invention is to provide a mechanism that absorbs deformation of the cover due to thermal expansion when the temperature rises in order to improve the durability of the cover that covers the magnet.
For example, the following structure is used as a mechanism for absorbing the thermal expansion of the cover.
1) A gap for absorbing thermal expansion is provided at least on the outer peripheral side of the cover.
2) The cover has a shape in which a main surface that faces the brake disk main surface and the magnetic pole surface group and a side surface that supports the main surface at least on the outer peripheral side are provided.
3) The cover has a shape in which a concave portion or a convex portion is provided on at least the outer peripheral side of the main surface facing the brake disk main surface and the magnetic pole surface group.
4) The cover has a shape in which a recess extending in the radial direction is provided on the main surface facing the brake disk main surface and the magnetic pole surface group.

  Since the eddy current type speed reducer of the present invention is provided with a mechanism for absorbing the thermal expansion of the cover, it can prevent inelastic deformation and thermal cracking of the cover due to repeated braking ON / braking OFF, and can be used for a long time. However, there is an advantage that an eddy current type speed reducer excellent in durability can be obtained because the deformation and fatigue crack are hardly generated.

  In an eddy current type speed reducer in which a magnet is brought close to and away from the main surface of the braking disk, inelastic deformation occurs in the cover when restraining thermal expansion of the cover when braking is ON. Accordingly, when braking ON / braking OFF is repeated, the deformation accumulates and the cover may come into contact with the magnet or the braking disk main surface, or a fatigue crack may occur in the cover.

  Therefore, the present inventor believes that providing a mechanism that absorbs the thermal expansion of the cover suppresses inelastic deformation of the cover, and makes it difficult for deformation and fatigue cracks to occur even when used for a long period of time. 1) At least the outer periphery of the cover If the gap is provided on the side, the thermal expansion of the cover can be absorbed by the gap, so that the cover is less likely to be inelastically deformed. 2) The cover has at least a main surface facing the brake disk main surface and the magnetic pole surface group, If the outer peripheral side is provided with a side surface that supports the main surface, the thermal expansion of the main surface can be absorbed by elastic deformation of the side surface, and 3) the cover faces the brake disk main surface and the magnetic pole surface group. If the main surface has a shape in which a concave portion or a convex portion is provided on at least the outer peripheral side, or a shape in which a concave portion extending in the radial direction is provided on the main surface, the concave portion or the convex portion absorbs the thermal expansion of the cover. Inelastically deformed Ensure that Kunar was established the above-mentioned present invention.

FIG. 1 shows an example of the eddy current type speed reducer of the present invention having a structure in which a gap for absorbing thermal expansion is provided between a cover and a case.
The eddy current type speed reducer according to the present invention includes a braking disk 2 attached to a rotating shaft 1 of a vehicle, and a braking unit (stator) disposed in the vicinity of the braking disk 2. The brake disc 2 is formed in a disc shape, and its central portion is fixed to the rotary shaft 1.

The braking unit comprises:
1) Multiple magnets (permanent magnets) 5
2) A ring-shaped holding member 6 for holding the magnet 5
3) Case 3 for housing the magnet 5 and the holding member 6
4) An actuator 7 such as an air cylinder, which includes a piston 7a and a piston rod 7b connected to the holding member 6 and reciprocates the piston 7a in order to move the magnet 5 toward and away from the brake disk 2.
5) Cover 11 which is a ring-shaped flat plate disposed at the end of brake disk 2 side of case 3
6) Fixing ring 9 for fixing the cover 11 to the case 3

  In the eddy current type reduction gear of the present invention having the above-described configuration, the present embodiment is characterized in that predetermined gaps 12 a and 12 b are provided between the case 3 and the outer peripheral side and inner peripheral side of the cover 11, for example. The gaps 12a and 12b provided between the cover 11 and the case 3 are preferably equal to or greater than the thermal expansion amount of the cover 11.

  In the eddy current type speed reducer having such a configuration, as shown by a solid line in FIG. 1, when the magnet 5 is brought close to the brake disk 2, the brake is turned on, and the magnetic flux generated by the magnet 5 acts on the brake disk 2. A braking force is generated. On the other hand, as indicated by an imaginary line in FIG. 1, the state in which the magnet 5 is separated from the braking disk 2 is the braking OFF state, and almost no magnetic flux acts on the braking disk 2 and almost no braking force is applied. Does not occur.

  By the way, since the magnetic flux acts on the rotating brake disk 2 during braking, an eddy current is generated near the surface of the brake disk 2 and the brake disk 2 generates heat. Since the heat generated in the brake disk 2 is transmitted to the cover 11 by heat conduction using radiation and air as a medium, the temperature of the cover 11 also rises as the temperature of the brake disk 2 increases during braking. When the temperature of the cover 11 rises, the cover 11, which is a ring-shaped flat plate, expands in the direction in which the diameter of the ring increases (in FIG. 1, the upward direction on the paper (radially outer peripheral side)).

  However, in the eddy current type reduction gear of the embodiment shown in FIG. 1, the initial setting state of the cover 11 where the temperature of the cover 11 has not increased is the inner peripheral side of the cover 11 as shown in FIG. Since the predetermined gap 12 is provided between the outer peripheral side and the case 3, even if the temperature of the cover 11 rises and the diameter of the cover 11 increases, as shown in FIG. The deformation of the cover 11 is not restricted by the case 3 due to the gap 12a on the side, and can be deformed relatively freely in the radial direction. As a result, thermal stress and thermal strain generated in the cover 11 are reduced, and inelastic strain is hardly generated. Therefore, when the braking is switched off and the temperature of the cover 11 decreases, the cover 11 returns to its original shape, and the cover 11 is less likely to be distorted.

  If the gap 12 is not provided between the outer peripheral side of the cover 11 and the case 3 or if the gap amount is insufficient, the thermal expansion of the cover 11 is restrained by the case 3 and the compressive stress in the direction of reducing the diameter of the cover 11 Compression distortion occurs. When the temperature of the cover 11 further increases, compressive stress and compressive strain increase, and inelastic strain occurs in the cover 11. In that case, after cooling, the cover 11 is distorted and the original state is not restored.

  When residual strain gradually accumulates in the cover 11 due to repetition of braking ON / braking OFF, a fatigue crack occurs in the cover 11 when the cover 11 comes into contact with the magnet 5 or the braking disk 2 or when inelastic strain is repeatedly applied. there is a possibility.

  Therefore, the gaps 12a and 12b between the cover 11 and the case 3 need to be provided with a sufficient amount, for example, the thermal expansion amount of the cover 11 or more. Note that the braking force and the dimensions of the cover 11 differ depending on the vehicle on which the eddy current speed reducer is mounted and the model of the eddy current speed reducer, and the rising temperature and the amount of thermal expansion of the cover 11 are different. Needless to say, the appropriate gap amount is selected individually.

  In the embodiment shown in FIG. 1, the cover 11 is provided with the gaps 12 a and 12 b on both the inner peripheral side and the outer peripheral side. However, either the inner peripheral side or the outer peripheral side, for example, only on the outer peripheral side. A gap 12a may be provided. That is, when the temperature rises, the cover 11 is deformed in the direction in which the diameter increases, so theoretically, in order to absorb the thermal expansion of the cover 11, it is only necessary to provide the gap 12 a only on the outer peripheral side of the cover 11. It is.

  However, when the temperature of the cover 11 rises excessively and the amount of the gap provided on the outer peripheral side becomes insufficient, resulting in compression inelastic strain in the direction of decreasing the diameter, the cooling of the cover 11 after cooling is more than before heating. Since the diameter is reduced, it is desirable to provide a gap 12b on the inner peripheral side of the cover 11 as well. Moreover, since the diameter of the cover 11 will become small if the outside air temperature falls from the time of manufacture and the atmospheric temperature of the cover 11 falls, it is desirable to provide the clearance 12b in advance on the inner peripheral side also from this point. If the gap 12b is not provided on the inner peripheral side, the inner peripheral side of the cover 11 comes into contact with the case 3, and tensile stress or tensile strain in the direction of increasing the diameter of the cover 11 occurs. Since the cover 11 may be deformed by repetition of such tensile stress and tensile strain and may come into contact with the magnet 5 or the brake disk 2 or a fatigue crack may occur, only the outer peripheral side as in the embodiment of FIG. It is better to provide the gap 12b on the inner peripheral side.

FIG. 3 shows a different embodiment of the eddy current type speed reducer of the present invention. In addition, description of the site | part which overlaps with the Example shown in FIG. 1 is abbreviate | omitted.
The cover 21 disposed between the magnet (permanent magnet) 5 and the brake disk 2 is formed of a non-magnetic material or a soft magnetic material, and faces the magnet 5 and the brake disk 2 (hereinafter referred to as “main surface 21a”). ”), The cross-section formed by side surfaces 21ba and 21bb that support the main surface 21a on the inner peripheral side and the outer peripheral side of the main surface 21a is formed in a U-shaped cross section. Examples of the material of the cover 21 include aluminum, aluminum alloy, carbon steel, cast iron, stainless steel, and the like. These may be used alone, or a plurality may be laminated. The cover 21 is formed by pressing, casting or the like.

  The cover 21 is fixed to the case 3 by screwing, caulking, press-fitting, adhesion, welding or the like at the end of the side surface 21b opposite to the main surface 21a. Therefore, the end portion of the cover 21 on the side fixed to the case 3 may be formed in a shape suitable for each fixing method, for example, an end portion shape as shown in FIG. For example, when attaching to the case 3 by caulking, it is easy to fix the cover 21 to the case 3, and since the case 3 can be sealed to prevent water and sand from entering the case 3, caulking is adopted as the fixing method. It is desirable to do.

  When the brake disk 2 generates heat when braking is applied, the heat is transmitted to the main surface 21a of the cover 21 facing the brake disk 2 by heat conduction using radiation and air, and the main surface 21a is heated. When the main surface 21a is heated, it thermally expands in the direction in which the ring diameter increases (in FIG. 3, the upper direction on the paper (radially outer peripheral side)). At this time, the side surfaces 21ba and 21bb of the cover 21 are moved from the state shown in FIG. 4 (a) to the outer peripheral side in the radial direction as shown in FIG. Tilt.

  When the side surfaces 21ba and 21bb are deformed in this way, the main surface 21a can expand and contract (deform) relatively freely without much thermal deformation, so the thermal stress and thermal strain generated on the main surface 21a are small, and the main surface 21a. Inelastic deformation is less likely to occur. Therefore, when switching to braking OFF and the temperature of the cover 21 is lowered, the cover 21 returns to its original state, and the cover 21 is less likely to be distorted. Therefore, even if braking ON / braking OFF is repeated over a long period of use, the cover 21 maintains the initial shape, and fatigue cracks do not easily occur, and the cover 21 having excellent durability can be obtained.

  By the way, in the embodiment of FIG. 3, the side surfaces 21ba and 21bb of the cover 21 are repeatedly deformed to incline in the radial direction as shown in FIGS. 4 (a) and 4 (b) as the main surface 21a is heated and cooled. Absorbs the thermal expansion of the surface 21a. Therefore, if the lengths of the side surfaces 21ba and 21bb (the width in the axial direction of the rotating shaft 1) are excessively short, the effect of absorbing the thermal expansion of the main surface 21a is small, so that sufficient durability may not be ensured. Since the braking force and the dimensions of the cover 21 differ depending on the shape and model of the main surface 21a, the lengths of the side surfaces 21ba and 21bb are determined based on the shape and model of the main surface 21a.

  Further, in the embodiment shown in FIG. 3, the description has been given of the case where the side surfaces are provided on both the inner peripheral side and the outer peripheral side of the main surface 21a. It may be good. The durability in this case is superior to that provided with the side surface only on the inner peripheral side, and is considered to be at the same level as that provided on both the inner peripheral side and the outer peripheral side. Note that the angle formed between the main surface 21a and the side surfaces 21ba and 21bb when viewed in the cross-sectional shape of FIG. 3 is not necessarily a right angle, and the same effect can be obtained with an acute angle or an obtuse angle. The intersection of the main surface and the side surface may have an arc shape.

  When inelastic deformation occurs in the cover 21, the cover 21 may come into contact with the magnet 5 and the brake disk 2 that are close to each other, and fatigue cracking may occur in the cover 21 when inelastic strain is repeatedly applied to the cover 21. However, in the eddy current type reduction gear of the embodiment of FIG. 3, the inelastic strain generated in the cover 21 is small, and these problems are unlikely to occur.

6 and 7 show different embodiments of the eddy current type speed reducer of the present invention. In addition, description of the site | part which overlaps with the Example shown in FIG. 1 is abbreviate | omitted.
The embodiment of FIG. 6 is provided with recesses 31aa and 31ab recessed on the magnet (permanent magnet) 5 side on the outer peripheral side and inner peripheral side of the cover 31, and the embodiment of FIG. In the figure, protrusions 31ba and 31bb protruding toward the brake disk 2 are provided on the circumferential side. 6 and 7 show only one section of the apparatus, it goes without saying that the recesses 31aa and 31ab and the protrusions 31ba and 31bb are desirably provided on the entire circumference. Further, the end portion of the case 31 is fixed to the case 3 by caulking, press fitting, adhesion, welding, or the like.

  In the following description, a surface that is located between the magnet (permanent magnet) 5 and the brake disk 2 and faces the magnet 5 and the brake disk 2 is referred to as a main surface 31 c of the cover 31. In the embodiment of FIG. 6, the cover 31 is composed of a main surface 31c and recesses 31aa, 31ab, and in the embodiment of FIG. 7, the cover 31 is composed of a main surface 31c and projections 31ba, 31bb.

  6 and 7, when the temperature of the main surface 31c of the ring-shaped cover 31 facing the braking disk 2 rises when braking is applied, the cover 31 has a direction in which the ring diameter increases ( In FIG. 6 and FIG. 7, it thermally expands in the upper direction (radial direction) on the paper surface. At this time, the concave portion 31aa or the convex portion 31ba on the outer peripheral side is deformed in a direction in which the width in the radial direction is reduced (so that the opening width on the side where the mouth of the concave portion 31aa or the convex portion 31ba is open) is reduced. 2 to absorb the thermal expansion of the main surface 31c that becomes high temperature. Further, the concave portion 31ab or the convex portion 31bb on the inner peripheral side is deformed in a direction in which the width in the radial direction is widened (so that the opening width of the concave portion 31ab or the convex portion 31bb is widened) to absorb the thermal expansion of the main surface 31c. Therefore, the restraining force with respect to the deformation of the main surface 31c is weakened, the inelastic deformation generated in the cover 31 is reduced, and even when used repeatedly for a long time, the cover 31 is hardly distorted and fatigue cracks are hardly generated.

  The deeper the recesses 31aa and 31ab and the larger the opening, the greater the effect of absorbing the thermal expansion of the main surface 31c. Therefore, it is desirable that the depth be as deep as possible and the opening be wide. . However, if the opening is excessively widened, the size of the case 3 may be increased and the mountability on the vehicle may be deteriorated. If the depth is excessively increased, the formability of the cover 31 may be deteriorated. Therefore, the appropriate depth and the width of the opening are determined according to the vehicle to be mounted, the model of the eddy current reduction device, and the method of forming the cover 31.

  As described above, when the concave portions 31aa and 31ab or the convex portions 31ba and 31bb are provided on the outer peripheral side and the inner peripheral side of the cover 31, the constraint on the thermal expansion of the main surface 31c is reduced, and the cover 31 is less likely to be inelastically deformed. . For this reason, when the cover 31 is cooled by switching to braking OFF, the cover 31 returns to its original shape and is less likely to be distorted. That is, when inelastic strain is repeatedly applied to the cover 31, fatigue cracks may occur in the cover 31 or the cover 31 may be distorted, but the eddy current type deceleration of the embodiment of FIGS. In the apparatus, these problems are less likely to occur. In the embodiments shown in FIG. 6 and FIG. 7, the description has been given of the case where the outer peripheral side and the inner peripheral side are provided with the concave portions (or convex portions). A cover with even higher durability can be obtained by providing a concave portion (or convex portion) on the inner peripheral side.

FIG. 8 shows a different embodiment of the eddy current type speed reducer of the present invention. In addition, description of the site | part which overlaps with the Example shown in FIG. 1 is abbreviate | omitted.
(A) of FIG. 8 is the figure which looked at a part of cover 41 from the front, (b) is BB sectional drawing of (a).

The cover 41 is provided with a plurality of concave portions 41a extending in the radial direction, for example, on the circumference at predetermined equal intervals. Further, the end portion of the cover 41 is fixed to the case 3 as shown in FIG. 8B by screwing, caulking, press fitting, adhesion, welding, or the like.
In the following description, the portion that is not the recess 41a on the surface facing the braking disk 2 is referred to as a main surface 41b.

  In the eddy current type reduction gear shown in FIG. 8, when the temperature of the ring-shaped cover 41 facing the braking disk 2 rises when braking is applied, the ring expands and the diameter of the ring increases. That is, the circumference of the ring becomes longer due to thermal expansion. At this time, if the concave portion 41a extending in the radial direction exists on the circumference, the concave portion 41a is deformed so that the width of the opening portion becomes small, and absorbs thermal expansion in the circumferential direction. When the cover 41 is cooled after switching to braking OFF, the opening of the recess 41a expands and returns to its original width.

  As described above, when the concave portion 41a is provided, the concave portion 41a expands and contracts to absorb the thermal expansion in the circumferential direction of the main surface 41b, and the constraint on the deformation of the main surface 41b is reduced. It becomes difficult. Therefore, when inelastic strain is repeatedly applied to the cover 41 due to long-term use, there is a possibility that the cover 41 may be fatigue cracked or the cover 41 may be distorted, but the eddy current of the embodiment of FIG. These problems are less likely to occur in the type reduction gear. The recess 41a is provided on the radiation extending from the center of the rotation axis. However, as shown in FIG. 8C, the recess 41a may be provided inclined in the circumferential direction, or the recess provided on the main surface 41b. There may be one 41a, and even when a plurality of 41a are provided, it is not always necessary to provide them at equal intervals. However, in consideration of the relative positional relationship with the magnet 5 described later, a plurality of recesses 41a may be provided at equal intervals. desirable.

  By the way, in order to increase the braking efficiency, it is necessary to bring the permanent magnet 5 as close to the braking disk 2 as possible. Therefore, a plurality of the concave portions 41a are arranged at predetermined intervals in the circumferential direction (permanent magnets) 5 and magnets. It is desirable to provide it so that it is located between the two. This is because if the recess 41a is provided at a position facing the magnet 5, the distance between the magnet 5 and the main surface 41b increases, and as a result, the distance between the magnet 5 and the braking disk 2 increases.

  Further, since the recess 41a has a greater effect of absorbing the thermal expansion of the main surface 41b as the depth is deeper and the opening is wider, it is desirable that the depth be as deep as possible and the opening be widened. However, when the recess 41 a is provided so as to be positioned between the magnets 5 as described above, the depth of the recess 41 a and the width of the opening are limited by the interval and thickness of the magnets 5. Therefore, an appropriate depth and an opening width are determined according to the model of the eddy current type reduction gear, that is, according to the shape and interval of the magnet 5.

  Since the above-described covers 11, 21, 31, and 41 are excellent in durability, the eddy current reduction device of the present invention provided with the covers 11, 21, 31, and 41 is naturally excellent in durability. Device. In the present invention, a permanent magnet, an electromagnet, or a combination of them can be used as a magnetic force source, and can indicate an eddy current in a braking disk.

In the above embodiment, a structure in which the pole piece is not provided in the covers 11, 21, 31, and 41 (pole piece-less) is shown, but a structure in which the pole piece is provided in the cover is also within the technical scope of the present invention. Needless to say, similar effects can be obtained.
Further, when the above embodiments are used in combination, a further effect can be obtained.

  As described above, since the eddy current reduction device of the present invention is excellent in durability, the eddy current of a vehicle that travels in an area having a difference in elevation or a vehicle that travels from an urban area to a remote area by traveling on a highway. Suitable for current type speed reducer.

It is the Example of the eddy current type | formula speed reducer of this invention, and is the figure which showed the upper half of the apparatus. It is the figure which showed the deformation | transformation of the cover of the eddy current type | formula speed reducer of this invention shown in FIG. 1, (a) when the temperature of a cover is not rising, (b) when the temperature of a cover rises. FIG. It is the Example which is a different Example of the eddy current type | formula speed reducer of this invention, and is the figure which showed the upper half of the apparatus. It is the figure which showed the deformation | transformation of the cover of the eddy current type | formula speed reducer shown in FIG. 3, (a) when the temperature of a cover is not rising, (b) is the figure which showed the time when the temperature of a cover rose. It is. (A) and (b) are the figures which showed the example of the cover shape of the eddy current type reduction gear shown in FIG. It is the Example which is a different Example of the eddy current type deceleration device of this invention, and is the figure which showed the cross section of the cover vicinity which provided the recessed part in the outer peripheral side and the inner peripheral side. It is the Example which is a different Example of the eddy current type deceleration device of this invention, and is the figure which showed the cross section of the cover vicinity which provided the convex part in the outer peripheral side and the inner peripheral side. It is the figure which is a different Example of the eddy current type speed reducer of this invention, and showed the cover which provided the recessed part extended in radial direction on the circumference, (a) is a front view of a part of cover, (b) (A) BB sectional drawing of (a), (c) is a figure similar to (a) which shows a different example. It is the figure which showed the cross section of the rotating shaft direction of the eddy current type | formula speed reducer of the type which makes a permanent magnet approach and space apart from a brake disc.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating shaft 2 Brake disk 3 Case 5 Permanent magnet 6 Holding member 7 Actuator 11 Cover 12a, 12b Clearance 21 Cover 21a Main surface 21ba, 21bb Side surface 31 Cover 31aa, 31ab Concavity 31ba, 31bb Convex part 31c Main surface 41 Cover 41a Concave 41b Main face

Claims (6)

  A magnetic force source group in which N poles and S poles are alternately arranged in the circumferential direction with a cover interposed at a position facing the brake disk attached to the rotating shaft is such that the magnetic pole surface of the magnetic force source is in contact with the main surface of the brake disk. An eddy current type speed reducer which is arranged so as to be parallel when braking and is provided so as to be able to advance and retreat in a case from a position close to the braking disk to a position away from the braking disk. An eddy current type speed reducer comprising a mechanism for absorbing.   2. The eddy current according to claim 1, wherein the mechanism for absorbing thermal expansion is a structure in which the cover is formed in a ring-shaped flat plate shape, and a gap is provided at least on the outer peripheral side of the cover and fixed to the case. Type speed reducer.   The mechanism for absorbing thermal expansion is a structure using a cover provided with a main surface facing the brake disk main surface and the magnetic pole surface group, and a side surface supporting the main surface at least on the outer peripheral side. The eddy current type speed reducer according to claim 1.   The mechanism for absorbing thermal expansion is a structure using a cover provided with a main surface facing the brake disk main surface and the magnetic pole surface group, and at least a concave portion or a convex portion on the outer peripheral side. The eddy current type speed reducer according to claim 1.   The mechanism for absorbing the thermal expansion is a structure using a cover provided with a recess extending in a radial direction on a main surface facing the brake disk main surface and the magnetic pole surface group. The eddy current type reduction gear described. 6. The eddy current reduction device according to claim 5, wherein a plurality of radially extending recesses provided on the main surface of the cover are provided at equal intervals on the circumference.

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