JP3882398B2 - Eddy current reducer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an eddy current type reduction device for assisting a foot brake as a main brake of a vehicle and for applying deceleration braking to the vehicle.
[0002]
[Prior art]
  When the vehicle goes down a long slope, it is necessary to continuously apply braking force to the vehicle in order to suppress acceleration generated in the vehicle. If this braking force is applied only by the foot brake, which is the main brake, The lining burns out and burns out. In order to solve this problem, large vehicles have conventionally been equipped with exhaust brakes and used as auxiliary brakes when going downhill.High superchargingUnder the present circumstances, a sufficient braking force cannot be obtained due to a reduction in the displacement of the engine. Therefore, an eddy current type reduction device has been proposed and put into practical use as a deceleration braking device (retarder) for reducing or limiting the traveling speed of the vehicle when the vehicle is going downhill.
[0003]
Eddy current type speed reducers are disclosed in, for example, Japanese Patent Publication No. 6-14782 and Japanese Patent Publication No. 7-118901.
Japanese Patent Publication No. 6-14782 discloses an eddy current type speed reducer comprising a braking drum attached to an output shaft of a transmission mounted on a vehicle and a plurality of permanent magnets at equal intervals in the circumferential direction. The mounted annular magnet means, the magnet means being brought close to the brake drum, the brake position where the magnet means applies a magnetic field to the brake drum, and the magnet means being separated from the brake drum to the brake release position where the magnet means does not exert a magnetic field on the brake drum. The actuator is selectively operated. When the magnet means is positioned at the braking position by the actuator, a braking action is performed. When the magnet means is positioned at the braking release position, the braking action is released.
[0004]
In addition, an eddy current type speed reduction device disclosed in Japanese Patent Publication No. 7-118901 is arranged to face a braking drum driven by an output shaft of a transmission mounted on a vehicle and an inner peripheral surface of the braking drum. Fixed magnet means provided, movable magnet means disposed adjacent to the fixed magnet means in the axial direction so as to be rotatable in the circumferential direction, and configured to be operable in a predetermined braking position and a non-braking position; The actuator comprises an actuator that selectively operates the movable magnet means to a braking position and a non-braking position. When the magnet means is positioned at the braking position by the actuator, a braking action is performed, and when the magnet means is positioned at the braking release position. The braking action is released.
[0005]
The magnet means includes a magnet support ring made of a magnetic material and a plurality of permanent magnets arranged on the outer peripheral surface of the magnet support ring at a predetermined interval. The plurality of permanent magnets have magnetic poles on the outer peripheral side and the inner peripheral side, and are arranged so that the N poles and the S poles are alternated. Thus, since the magnetic pole of each magnet which comprises a magnet means is formed in the outer peripheral side and the inner peripheral side, it is necessary to enlarge the dimension of the circumferential direction of a magnet.
[0006]
As a technique for solving the above problem, the present applicant has arranged a magnet support cylinder made of a non-magnetic material inside a brake drum driven by a rotating shaft, and a plurality of magnet support cylinders are arranged at equal intervals on the outer peripheral surface of the magnet support cylinder. The eddy current type deceleration provided with magnet means in which the magnets are arranged so that the polarities of the end portions in the circumferential direction are the same on opposite surfaces, and a ferromagnetic material is arranged between the magnets A device was proposed as Japanese Patent Application No. 10-362273.
[0007]
[Problems to be solved by the invention]
Thus, each of the eddy current type speed reducers is configured such that a plurality of magnets constituting the magnet means are arranged on the outer peripheral surface of the magnet support cylinder, and therefore the magnet means corresponds to the thickness of the magnet support cylinder. The height dimension in the radial direction is increased by an amount corresponding to this, so that the weight of the magnet means and the magnet housing that accommodates the magnet means increases. Further, when the height of the magnet means in the radial direction is increased, if the diameter of the brake drum is made the same in order to obtain a predetermined braking capability, the inner diameter of the magnet means becomes small, for example, the output of a transmission mounted on a vehicle. The radial height of the mounting flange for mounting the brake drum mounted on the shaft must be reduced. If the height dimension in the radial direction of the mounting flange mounted on the output shaft is reduced, the mounting operation becomes difficult when, for example, a propeller shaft is mounted on the mounting flange.
[0008]
  The present invention has been made in view of the above facts,The technical challenge isEddy current type speed reducer capable of reducing the radial height of the magnet means,In particular, an eddy current type comprising a fixed magnet means and a rotatable movable magnet means arranged opposite to the inner peripheral surface of the brake drum, and selectively operating the movable magnet means to a braking position and a non-braking position. Reduction gearIs to provide.
[0009]
[Means for Solving the Problems]
  According to the present invention,The above technical issuesTo solve,
"A brake drum driven by a rotating shaft, a fixed magnet means disposed to face the inner peripheral surface of the brake drum, and arranged to be rotatable in the circumferential direction adjacent to the fixed magnet means in the axial direction. In the eddy current reduction device comprising the movable magnet means configured to be operable at a predetermined braking position and a braking release position,
The fixed magnet means and the movable magnet means are each provided with a ring-shaped side plate made of a non-magnetic material and a side surface of the side plate at a predetermined interval in the circumferential direction, and the polarities of the end portions in the circumferential direction are relative to each other. A plurality of magnets arranged to have the same polarity on the facing surface, and a plurality of pole pieces arranged on both sides of the plurality of magnets,
The pole pieces of the fixed magnet means and the movable magnet means are respectively disposed so as to protrude from the outer peripheral surface of the side plate, and the outer peripheral side end portions protrude in directions approaching each other. ''
An eddy current type speed reducer characterized by the above is provided.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, a preferred embodiment of an eddy current type speed reducer configured according to the present invention is illustrated.1 to 7Will be described in more detail.
[0014]
FIG. 1 is a cross-sectional view of an eddy current type speed reducer constructed according to the present invention mounted on an output shaft of a transmission mounted on a vehicle. The eddy current type speed reducer in the illustrated embodiment includes a braking drum 20 that is spline-fitted to the output shaft 11 of the transmission 10 and fixed to a mounting flange 13 that is mounted by a nut 12. The braking drum 20 includes a boss 21 having a mounting portion 211, an end wall 22 extending upward from the right end in the figure of the boss 21, and an annular braking attached to the upper end of the end wall 22 by fixing means such as welding. The mounting portion 211 of the boss 21 is fixed to the mounting flange 13 by fastening means such as a bolt 14a and a nut 14b. The braking portion 23 is made of a magnetic material, and a plurality of heat radiating fins 24 are mounted on the outer peripheral surface thereof.
[0015]
  Next, the magnet housing 30 disposed facing the inner peripheral surface of the braking portion 23 of the braking drum 20 and the magnet means 40 accommodated in the magnet housing 30 will be described.
  The magnet housing 30 includes an attachment member 31 and a hollow annular housing body 32 that is integrally formed on the outer periphery of the attachment member 31. The attachment member 31 is formed in a disk shape, and an inner peripheral end thereof is attached to the case 15 of the transmission 10 by a fastening bolt 16. The hollow annular housing body 32 includes an inner peripheral wall 321, an outer peripheral wall 322, a right end wall 323, a left end wall 324, and an intermediate wall 325 formed so as to protrude upward from the left end in the drawing of the outer peripheral wall 322. 322 is disposed to face the inner peripheral surface of the annular braking portion 23 constituting the braking drum 20 with a slight gap. The outer peripheral wall 322 and the right end wall 323 constituting the housing main body 32 are formed of a magnetic insulating material such as non-magnetic material such as aluminum, and the outer peripheral wall 322 has a predetermined circumferential direction as shown in FIG. A plurality of windows 322a are formed at intervals. A ferromagnetic material 326 made of a ferromagnetic material is disposed in the plurality of windows 322a. Preferably, the ferromagnetic body 326 is formed when the outer peripheral wall 322 is molded.Cast. The ferromagnetic body 326 may be attached to the outer peripheral wall 322 by welding. A lid plate 327 is attached to the upper ends of the right end wall 323 and the intermediate wall 325 by mounting bolts 328.
[0016]
The magnet means 40 is disposed with the inner peripheral surface fitted to the outer peripheral surface of the inner peripheral wall 321, and the fixed magnet means 50 disposed at a position facing the ferromagnetic body 326 mounted on the outer peripheral wall 322. And a movable magnet means 60.
The fixed magnet means 50 will be described with reference to FIGS. The fixed magnet means 50 in the illustrated embodiment includes a pair of annular side plates 51 and 52 disposed at a predetermined interval, and a predetermined interval in the circumferential direction between the side plates 51 and 52. A plurality of permanent magnets 53 are provided, and pole pieces 54 made of a ferromagnetic material are provided on both sides of the plurality of permanent magnets 53, respectively. The side plates 51 and 52 are made of a nonmagnetic material. The plurality of permanent magnets 53 are made of a rare earth such as neodymium having a light weight and a strong magnetic force, have a magnetic pole at the circumferential end, and have the same polarity on the surface where the polarities of the circumferential end are opposite to each other. It is arranged to be. Therefore, the pole piece 54 disposed on the N pole side of the permanent magnet 53 functions as the N pole, and the pole piece 54 disposed on the S pole side of the permanent magnet 53 functions as the S pole. The permanent magnet 53 has a height dimension larger than the height of the side plates 51 and 52, and the outer peripheral side is disposed so as to protrude from the outer peripheral surfaces of the side plates 51 and 52. The pole piece 54 is formed such that the central portion on the outer peripheral side protrudes from the permanent magnet 53, and this central portion is formed so that the side adjacent to the movable magnet means 60 (side plate 51 side) projects toward the movable magnet means 60. Has been. The plurality of permanent magnets 53 and the pole pieces 54 arranged between the side plates 51 and 52 in this way are inserted through the bolts 55 through the bolt insertion holes provided in the side plates 51 and 52 and the pole piece 54. The nuts 56 are screwed onto the bolts 55 to be attached to the side plates 51 and 52. The fixed magnet means 50 configured as described above is fixed to the right end wall 323 of the housing body 32 by a fixing pin 329.
[0017]
Similarly to the fixed magnet means 50, the movable magnet means 60 also includes a pair of annular side plates 61 and 62, and a plurality of pieces disposed between the side plates 61 and 62 at predetermined intervals in the circumferential direction. The permanent magnet 63 includes a pole piece 64 made of a ferromagnetic material disposed on both sides of each of the plurality of permanent magnets 63. The side plates 61 and 62 are made of a nonmagnetic material. The plurality of permanent magnets 63 are made of rare earth such as neodymium, have a magnetic pole at the circumferential end, and are arranged so that the polarities of the circumferential end are the same on opposite surfaces. . Therefore, the pole piece 64 disposed on the N pole side of the permanent magnet 63 functions as an N pole, and the pole piece 64 disposed on the S pole side of the permanent magnet 63 functions as an S pole. The permanent magnet 63 has a height dimension larger than the height of the side plates 61 and 62, and the outer peripheral side is disposed so as to protrude from the outer peripheral surfaces of the side plates 61 and 62. The pole piece 64 is formed so that the outer peripheral side central portion protrudes from the permanent magnet 63, and the central portion protrudes toward the fixed magnet means 50 on the side adjacent to the fixed magnet means 50 (side plate 61 side). Is formed. The plurality of permanent magnets 63 and the pole pieces 64 arranged between the side plates 61 and 62 in this way are bolts provided on the side plates 61 and 62 and the pole piece 64 in the same manner as the fixed magnet means 50. The bolts are inserted into the insertion holes, and the nuts 56 are screwed together so that the side plates 61 and 62 are attached. Note that the pitch of the permanent magnet 63 and the pole piece 64 of the movable magnet means 60 is the same as the pitch of the permanent magnet 53 and the pole piece 54 of the fixed magnet means 50. An annular sliding member 67 formed of a stainless steel plate and coated with, for example, Teflon (trade name), which is a material having a small friction coefficient, is press-fitted into the inner peripheral surface of the movable magnet means 60 configured as described above. Is installed. The movable magnet means 60 is arranged to be slidable in the circumferential direction by bringing the sliding member 67 into contact with the outer peripheral surface of the inner peripheral wall 321 of the housing main body 32.
[0018]
An arm 66 is attached to the side plate 62 opposite to the fixed magnet means 50 of the movable magnet means 60 (left side in FIG. 1). The arm 66 is connected to a magnet actuated actuator (not shown). A magnet actuating actuator (not shown) slides the movable magnet means 60 on the outer peripheral surface of the inner peripheral wall 321 in the circumferential direction. Note that the operation amount of the movable magnet means 60 by the magnet actuator is set to a dimension corresponding to the pitch of the permanent magnet 63 and the pole piece 64 in the illustrated embodiment.
[0019]
As described above, the magnet means 40 including the fixed magnet means 50 and the movable magnet means 60 includes an annular side plate and a plurality of permanent magnets disposed on the side plate at predetermined intervals in the circumferential direction. And a magnetic pole piece made of a ferromagnetic material disposed on both sides of each of the plurality of permanent magnets, so that conventional magnet means having a plurality of permanent magnets disposed on the outer peripheral surface of the magnet support cylinder Compared to the above, the height in the radial direction can be reduced, and the weight of the magnet means 40 and the magnet housing 30 that houses the magnet means 40 can be reduced. Further, since the height of the magnet means in the radial direction can be reduced, the inner diameter of the magnet means 40 can be increased when the diameter of the brake drum 20 is the same in order to obtain a predetermined braking capability. . Accordingly, it is possible to increase the height in the radial direction of the mounting flange 13 that is mounted on the output shaft 11 and mounts the braking drum 20. When the propeller shaft is mounted on the mounting flange 13, for example, the mounting work is reduced. It becomes easy.
[0020]
The eddy current type speed reducer in the illustrated embodiment is configured as described above, and the operation thereof will be described below.
First, the braking operation will be described. The movable magnet means 60 is rotated in one direction by a magnet actuating actuator (not shown), and the permanent magnets 53 of the fixed magnet means 50 and the magnets having the same polarity as the permanent magnet 63 of the movable magnet means 60 are adjacent to each other as shown in FIG. A braking action is performed by positioning the brake position.
[0021]
Hereinafter, the braking action will be described with reference to FIG.
When the magnets having the same polarity of the permanent magnet 53 of the fixed magnet means 50 and the permanent magnet 63 of the movable magnet means 60 are positioned at the adjacent braking positions, the pole piece 54 of the adjacent fixed magnet means 50 and the movable magnet means 60 Since the pole piece 64 has the same polarity, no magnetic circuit is formed between the pole piece 54 of the fixed magnet means 50 and the pole piece 64 of the movable magnet means 60. Therefore, as shown in FIG. 5, the fixed magnet means 50 and the movable magnet means 60 are arranged such that the permanent magnet 53 (63) and the pole piece 54 (64) adjacent to each other in the circumferential direction are disposed between the braking portion 23 and the non-movable magnet means 50. The ferromagnetic material 326 made of a ferromagnetic material magnetically insulated by the outer peripheral wall 322 of the housing body 32 formed of a magnetic material is magnetically connected to the braking portion 23 of the braking drum 20 using a magnetic path. As a result, a magnetic circuit 41 is formed that passes through the fixed magnet means 50 and the movable magnet means 60 on the fixed side and the braking portion 23 of the braking drum 20 on the rotation side. Accordingly, an eddy current is generated on the inner peripheral surface of the braking portion 23 due to the relative speed difference between the fixed magnet means 50 and the movable magnet means 60 and the braking portion 23 of the braking drum 20, and the braking portion 23 receives the braking torque.
[0022]
Next, the braking release operation will be described.
From the state shown in FIG. 3, the movable magnet means 60 is rotated in the other direction by operating the movable magnet means 60 in the other direction by a magnet actuating actuator (not shown). As shown in FIG. 6, when the permanent magnet 53 of the fixed magnet means 50 and the permanent magnet 63 of the movable magnet means 60 are positioned at adjacent brake release positions, the braking action is released.
[0023]
Hereinafter, the reason why the braking action is released will be described with reference to FIGS. 6 and 7.
As shown in FIGS. 6 and 7, when positioned at the brake release position, the pole piece 54 of the adjacent fixed magnet means 50 and the pole piece 64 of the movable magnet means 60 have different polarities, so that the fixed magnet A magnetic short circuit 42 is formed between the means 50 and the movable magnet means 60 as shown in FIG. At this time, the pole piece 54 of the fixed magnet means 50 and the pole piece 64 of the movable magnet means 60 are formed so that their outer peripheral end portions protrude in directions approaching each other, so that the magnetic short circuit 42 is reliably formed. can do. Accordingly, the magnetic field that acts perpendicularly to the inner surface of the braking portion 23 of the braking drum 20 is extremely weak, so that no braking torque is generated in the braking portion 23 and the braking action is released.
[0024]
  By the way, the method of fixing the pole piece using the side plate similar to the present invention is applicable to other types of eddy current type reduction gears, and one reference example thereof is as follows.This will be described with reference to FIGS. In addition, it shows in FIG. 8 thru | or FIG.Reference example1 is different from the embodiment shown in FIGS. 1 to 7 in the magnet housing 30 and the magnet means 40 accommodated in the magnet housing 30, but other configurations are shown in FIGS. Since it is substantially the same as the embodiment, the same member is denoted by the same reference numeral, and the detailed description thereof is omitted.
  The magnet housing 30 in the eddy current type speed reducer shown in FIG. 8 has an outer peripheral wall 322a constituting the hollow annular housing body 32, that is, an outer peripheral wall facing the inner peripheral surface of the annular braking portion 23 constituting the braking drum 20. 322a is formed of a thin plate made of a nonmagnetic material. The outer peripheral wall 322a is formed in a cylindrical shape with a thickness of about 0.5 to 1.0 mm using, for example, austenitic stainless steel, aluminum, a heat-resistant synthetic resin, a carbon material containing reinforcing fibers, and the like by a fixing means such as a bolt. The housing body 32 is connected by a right end wall 323 and an intermediate wall 325. As described above, in the eddy current type speed reducer shown in FIGS. 8 to 10, the outer wall 322a constituting the housing body 32 is formed of a thin plate made of a non-magnetic material, so that the embodiment shown in FIGS. The ferromagnetic body 326 can be removed.
[0025]
  The magnet means 40 includes a pair of annular side plates 71 and 72 and a circumferential direction between the side plates 71 and 72 in the same manner as the fixed magnet means 50 and the movable magnet means 60 in the embodiment shown in FIGS. A plurality of permanent magnets 73 disposed at predetermined intervals, and pole pieces 74, 74 made of a ferromagnetic material disposed on both sides of the plurality of permanent magnets 73, respectively. The side plates 71 and 72 are made of a nonmagnetic material. The plurality of permanent magnets 73 are made of rare earth such as neodymium, have a magnetic pole at the circumferential end, and are arranged so that the polarities of the circumferential end are the same on opposite surfaces. . Therefore, the pole piece 74 disposed on the N pole side of the permanent magnet 73 functions as the N pole, and the pole piece 74 disposed on the S pole side of the permanent magnet 73 functions as the S pole. The permanent magnet 73 has a height dimension larger than the height of the side plates 71, 72, and the outer peripheral side is disposed so as to protrude from the outer peripheral surfaces of the side plates 71, 72. In addition,The form shown in FIG., A gap is provided between the pole piece 74 and the pole piece 74. The plurality of permanent magnets 73 and pole pieces 74 arranged between the side plates 71 and 72 in this way are inserted through the bolts 75 through the bolt insertion holes provided in the side plates 71 and 72 and the pole piece 74. The bolts 75 are attached to the side plates 71 and 72 by being screwed onto the nuts 76. The magnet means 40 configured as described above is fitted to the outer peripheral surface of the inner peripheral wall 321 of the housing main body 32 and is slidable in the axial direction.
[0026]
An operating rod 76 is attached to the left side plate 72 of the magnet means 40 in FIG. The actuating rod is connected to a magnet actuating actuator (not shown). A magnet actuating actuator (not shown) operates the magnet means 40 to a braking position indicated by a solid line in FIG. 8 and a braking release position indicated by a two-dot chain line in FIG.
[0027]
The eddy current type speed reducer shown in FIGS. 8 to 10 is configured as described above, and its operation will be described.
In the case where braking is performed by the eddy current type reduction gear, a braking action is performed by operating a magnet operating actuator (not shown) and positioning the permanent magnet 73 at a braking position indicated by a solid line in FIG. That is, in the magnet means 40, as shown in FIG. 10, a permanent magnet 73 adjacent in the circumferential direction and pole pieces 74, 74 disposed on both sides of the permanent magnet 73 are disposed between the brake unit 23. A magnetic circuit 43 passing through the braking portion 23 of the braking drum 20 through a thin outer peripheral wall 322a made of a nonmagnetic material is formed. Therefore, when the rotating braking unit 23 crosses the magnetic field, an eddy current is generated in the braking unit 23, and the braking unit 23 receives a braking torque.
[0028]
Next, a case where braking is released will be described.
From a braking state indicated by a solid line in FIG. 8, a magnet actuating actuator (not shown) is operated to position the magnet means 40 at a braking release position indicated by a two-dot chain line in FIG. When the magnet means 40 is positioned at the braking release position, the permanent magnet 73 does not face the braking portion 23 that constitutes the braking drum 20, so that the braking portion 23 does not receive braking torque.
[0029]
  next,Other reference examples in which the method of fixing the pole piece using the side plate similar to the present invention is applied to another type of eddy current type speed reducerThis will be described with reference to FIGS. 11 to 13. In addition, it shows in FIG. 11 thru | or FIG.Reference exampleThe eddy current type speed reducer is shown in FIG.Form1 is applied to the magnet housing 30 in the embodiment shown in FIG.Each form aboveThe same members are denoted by the same reference numerals, and detailed description thereof is omitted.
  As shown in FIGS.Reference exampleThe magnet means 40 includes a pair of annular side plates 71 and 72, a plurality of permanent magnets 73 disposed between the side plates 71 and 72 at a predetermined interval in the circumferential direction, Each of the plurality of permanent magnets 73 includes pole pieces 74 and 74 made of a ferromagnetic material disposed on both sides. An annular sliding member 77 formed of a stainless steel plate and coated with, for example, Teflon (trade name), which is a material having a small friction coefficient, is press-fitted into the inner peripheral surface of the magnet means 40 configured as described above. It is installed. The magnet means 40 is disposed so as to be slidable in the circumferential direction by bringing the sliding member 77 into contact with the outer peripheral surface of the inner peripheral wall 321 of the housing main body 32. In addition, the circumferential length of each set including the permanent magnet 73 and the pole pieces 74 and 74 is configured to have a dimension substantially corresponding to the circumferential length of the ferromagnetic body 326 disposed on the outer peripheral wall 322 of the magnet housing 30. The interval is set to a dimension corresponding to the pitch of the ferromagnetic material 326.
[0030]
The eddy current type speed reducer shown in FIGS. 11 to 13 is configured as described above, and its operation will be described.
When braking is performed by the eddy current type speed reducer, a magnet actuating actuator (not shown) is actuated to rotate the magnet means 40 in one direction so that each permanent magnet 73 is strongly connected to the ferromagnetic material 326 as shown in FIG. It positions so that it may be located between the magnetic bodies 326. Accordingly, the pole pieces 74 and 74 disposed on both sides of the permanent magnet 73 face the adjacent ferromagnetic body 326, respectively. As a result, as shown in FIG. 12, a magnetic circuit 44 that passes through the braking portion 23 of the braking drum 20 is formed, and the braking portion 23 receives braking torque.
[0031]
Next, the braking release operation will be described.
From the state shown in FIG. 12, a magnet actuator (not shown) is operated to rotate the magnet means 40 in the other direction, and each permanent magnet 73 is opposed to the central portion of the ferromagnetic body 326 as shown in FIG. Position to position. Accordingly, the pole pieces 74 and 74 disposed on both sides of the permanent magnet 73 also face the ferromagnetic body 326, respectively. As a result, a magnetic short circuit 44 is formed between the permanent magnet 73, the pole pieces 74 and 74, and the ferromagnetic body 326 as shown in FIG. For this reason, the magnetic field acting perpendicularly to the inner surface of the braking portion 23 of the braking drum 20 is extremely weak, so that no braking torque is generated in the braking portion 23 and the braking action is released.
[0032]
Although the present invention has been described based on the illustrated embodiment, the present invention is not limited to the embodiment, and various modifications are possible within the scope of the technical idea of the present invention. For example, in the illustrated embodiment, the magnet means is configured such that the magnet and the pole piece are sandwiched by a pair of side plates. However, the magnet means is configured such that the magnet and the pole piece are mounted on the side surface of one side plate. Also good.
[0033]
【The invention's effect】
Since the eddy current type speed reducer according to the present invention is configured as described above, the following effects can be obtained.
[0034]
  That is, according to the present invention, the magnet means disposed opposite to the inner peripheral surface of the braking drum driven by the rotating shaft is provided with the annular side plate and the side surface of the side plate in a predetermined direction in the circumferential direction. A plurality of magnets arranged at intervals and arranged such that the polarities of the end portions in the circumferential direction are the same on opposite surfaces, and arranged on both sides of each of the plurality of magnetsPole piece made of ferromagnetic materialAs compared with the conventional magnet means in which a plurality of permanent magnets are arranged on the outer peripheral surface of the magnet support cylinder, the radial height thereof can be reduced, and the magnet means and the magnet The weight of the magnet housing that houses the means can be reduced. Further, since the height of the magnet means in the radial direction can be reduced, the inner diameter of the magnet means can be increased when the diameter of the brake drum is the same in order to obtain a predetermined braking capability. Therefore, it is possible to increase the radial height of the mounting flange for mounting the braking drum mounted on the rotating shaft, and for example, when mounting a propeller shaft of a vehicle on the mounting flange, the mounting work is easy. Become.
  And the eddy current type speed reducer of the present invention isThe fixed magnet means disposed opposite to the inner peripheral surface of the brake drum, and the movable magnet means disposed rotatably adjacent to the fixed magnet means in the circumferential direction. The fixed magnet means and the pole pieces of the movable magnet means are arranged so as to protrude from the outer peripheral surface of the side plate, and the outer peripheral side end portions protrude in directions approaching each other. Therefore, it is possible to reliably form a magnetic short circuit between the opposing pole pieces and a magnetic circuit to the outer braking drum, and no braking torque (drag torque) is generated when the brake is released, and more reliable when braking. A large braking force can be generated.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a principal part showing an embodiment of an eddy current type speed reducer configured in accordance with the present invention.
FIG. 2 is a partial perspective view of a magnet housing and magnet means constituting the eddy current type reduction gear shown in FIG.
3 is a partial perspective view of magnet means constituting the eddy current type speed reducer shown in FIG. 1. FIG.
4 is a partial plan view of a fixed magnet means constituting the magnet means shown in FIG. 3. FIG.
FIG. 5 is a cross-sectional view taken along line AA in the braking state of the eddy current type speed reducer shown in FIG.
6 is a partial plan view of the magnet means shown in FIG. 3 in a brake release state.
FIG. 7 is a cross-sectional view of a main part in a braking release state of the eddy current type reduction gear shown in FIG. 1;
[Fig. 8]The figure which shows one reference example of the eddy current type reduction gear which uses the side plate similar to this invention.
9 is a partial front view of magnet means constituting the eddy current type reduction gear shown in FIG.
10 is a cross-sectional view taken along the line BB in the braking state of the eddy current type reduction gear shown in FIG.
FIG. 11The figure which shows another reference example of the eddy current type reduction gear which uses the side plate similar to this invention.
12 is a cross-sectional view taken along the line CC of the eddy current reduction device shown in FIG. 11 in a braking state.
13 is a cross-sectional view taken along line CC in the brake released state of the eddy current type reduction gear shown in FIG.
[Explanation of symbols]
    10: Transmission
    11: Output shaft of transmission
    20: Braking drum
    23: Braking part of braking drum
    24: Radiation fin
    30: Magnet housing
    40: Magnet means
    50: Fixed magnet means
    51: Side plate
    52: Side plate
    53: Permanent magnet
    54: Pole piece
    60: Movable magnet means
    61: Side plate
    62: Side plate
    63: Permanent magnet
    64: Pole piece
    65: Sliding member
    66: Arm
    71: Side plate
    72: Side plate
    73: Permanent magnet
    74: Pole piece
    76: Actuating rod

Claims (1)

A brake drum driven by a rotating shaft, a fixed magnet means disposed to face the inner peripheral surface of the brake drum, and arranged to be rotatable in the circumferential direction adjacent to the fixed magnet means in the axial direction. In the eddy current reduction device comprising the movable magnet means configured to be operable at a predetermined braking position and a braking release position,
The fixed magnet means and the movable magnet means are each provided with a ring-shaped side plate made of a non-magnetic material and a side surface of the side plate at a predetermined interval in the circumferential direction, and the polarities of the end portions in the circumferential direction are relative to each other. A plurality of magnets arranged to have the same polarity on the facing surface, and a plurality of pole pieces arranged on both sides of the plurality of magnets ,
The pole pieces of the fixed magnet means and the movable magnet means are respectively disposed so as to protrude from the outer peripheral surface of the side plate, and the outer peripheral side end portions are protruded in directions approaching each other.
An eddy current type speed reducer characterized by that.

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