JP2001037204A - Eddy current decelerating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an eddy current decelerating device wherein increase of temperature of good conductor is restrained by increasing volume of the good conductor and heat capacity and improving cooling property due to air. SOLUTION: This eddy current decelerating device consists of a brake drum 15 which is combined with a rotary shaft 21 and composed of conductor, a guide cylinder 6 which is fixed on a stationary part so as to face the inside of the brake drum 15 and composed of nonmagnetic member, a pivotable magnet retaining cylinder 9 and an immovable magnet retaining cylinder 9a which are accommodated in an inner vacant part 20 of the guide cylinder 6, a large number of magnets 8, 8a which are combined with the outer peripheral surfaces of the magnet retaining cylinders 9, 9a at equal intervals in the peripheral direction, and ferromagnetic plates 31 which are cast in an outer cylinder 6a of the guide cylinder 6 so as to face the respective magnets 8, 8a. Annular members 41-44 composed of good conductor like copper are continuously combined with an end wall surface of the brake drum 15 and an end portion of an inner peripheral surface 15b which end portion does not face the ferromagnetic plates 31. The annular members 42, 44 of the inner peripheral surface 15b are made thicker than the annular members 41, 43 of the end wall surface of the brake drum 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eddy current reduction device for assisting a friction brake of a vehicle or the like, and more particularly, to improving the flow of an eddy current by connecting a good conductor such as copper to both ends of a braking drum. The present invention relates to an eddy current reduction device with improved power.

[0002]

2. Description of the Related Art In a conventional eddy current reduction device, a magnet support cylinder is disposed inside a brake drum made of a conductor such as steel or low-carbon steel. When a magnet (including an electromagnet) coupled so that the polarity with respect to the inner peripheral surface is alternately different in the circumferential direction is brought closer to the inner peripheral surface of the braking drum, the rotating braking drum crosses the magnetic field from the magnet and is based on the eddy current. A braking force is generated on the braking drum. Through nickel plating layers on both ends of the braking drum,
An annular body (cylindrical body or annular plate) made of a good conductor such as copper
Is combined, the flow of the eddy current is improved, and the braking ability is improved.

However, at the time of braking, the eddy current concentrates on the ring made of a good conductor, and the temperature of the ring made of a good conductor becomes:
There is almost no difference from the temperature at the axially central portion of the inner peripheral surface of the braking drum. At a high temperature exceeding 600 ° C., the low-carbon steel constituting the braking drum has better heat resistance than the copper constituting the annular body made of a good conductor, so that the temperature of the annular body made of a good conductor eventually causes a vortex. The operation range of the current reduction device is limited, and the braking performance of the braking drum having the annular body made of a good conductor cannot be sufficiently exhibited. In other words, if the annular body made of a good conductor is overheated, an obstacle such as cracking of the annular body or peeling off from the braking drum occurs, so that there is a limit to the improvement of the braking capacity. Therefore, in order to further improve the braking ability, it is required to suppress the temperature rise of the annular body made of a good conductor.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to increase the heat capacity by increasing the volume of a good conductor, and to enhance the cooling performance by outside air to suppress the temperature rise of the good conductor. SUMMARY OF THE INVENTION It is an object of the present invention to provide an eddy current speed reducer.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a brake drum made of a conductor connected to a rotating shaft and a non-rotating portion such as a vehicle body facing the inside of the brake drum. A guide tube made of a non-magnetic material having an inner space with a rectangular cross section attached, a magnet support tube housed in the inner space of the guide tube, at least one of which is rotatable, and an outer peripheral surface of the magnet support tube. It has a number of magnets connected at equal intervals in the circumferential direction, and a ferromagnetic plate cast in the outer tube portion of the guide tube so as to face the respective magnets, and a braking force based on eddy current due to a magnetic field from the magnets In the eddy current reduction device that generates the braking drum, the end of the inner peripheral surface of the braking drum that does not face the ferromagnetic plate and the end wall surface of the braking drum are continuously connected to each other by a good conductor such as copper. And an annular body on the end wall surface of the braking drum. And characterized in that increasing the thickness of the annular body of the inner peripheral surface of the brake drum than.

Further, the structure of the present invention comprises a braking drum made of a conductor connected to a rotating shaft and an inner space having a rectangular cross section attached to a non-rotating part of a vehicle body or the like so that a half part faces the inside of the braking drum. A guide cylinder having the magnet, a magnet support cylinder accommodated in the inner space of the guide cylinder so as to be movable in the axial direction, a large number of magnets coupled to the outer peripheral surface of the magnet support cylinder at equal circumferential intervals, A portion made of a magnetic material that does not face the inner peripheral surface of the braking drum of the cylindrical portion, and an inner circumferential surface of the braking drum of an outer cylindrical portion of the guide cylinder that is made of a non-magnetic material, and faces each of the magnets. An eddy current reduction device for generating a braking force based on an eddy current on the braking drum by a magnetic field from the magnet, wherein the ferromagnetic plate on an inner peripheral surface of the braking drum is provided. And the end wall of the braking drum Subsequently, an annular body made of a good conductor such as copper is joined, and the thickness of the annular body on the inner peripheral surface of the brake drum is made thicker than the annular body on the end wall surface of the brake drum. .

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, an L-shaped cross-section made of a good conductor such as copper is connected to both ends of the inner peripheral surface of the brake drum and both end wall surfaces of the brake drum. By making the thickness of the annular body coupled to the bad inner peripheral surface thicker than that of the annular body coupled to the end wall surface, the density of the eddy current is reduced, and the temperature rise of the annular body due to Joule heat is suppressed. . Also, in order to enhance the heat radiation of the annular body coupled to the inner peripheral surface of the braking drum, a number of axial grooves are provided in the annular body at intervals in the circumferential direction. As the braking drum rotates, the annulus acts as an impeller and directs outside air to the annulus for cooling.

[0008]

FIG. 1 is a front sectional view of an eddy current reduction device according to the present invention, and FIG. 2 is a side sectional view of the eddy current reduction device. The eddy current reduction device includes, for example, a braking drum 15 made of a conductor such as steel coupled to the output rotation shaft 21 of the vehicle transmission;
A guide tube 6 made of a non-magnetic material is provided inside the braking drum 15, and a movable magnet support tube 9 and an immovable magnet support tube 9 a accommodated in an inner space 20 having a rectangular cross section of the guide tube 6. ing. The braking drum 15 is a flange 1 of the boss 19.
9a, together with the end wall of the braking drum 23 of the parking brake, is superimposed on the mounting flange 22 fitted to the spline 22a of the rotating shaft 21 and fastened by the nut 21a, and fastened to the plurality of bolts 24 by the nut. You.
The base end of the brake drum 15 provided with the cooling fin 15a is connected to a number of support arms 16 extending radially from the boss 19. At both ends of the inner peripheral surface 15b of the braking drum 15, annular bodies 41 and 42 and annular bodies 43 and 43 made of a good conductor such as copper are provided.
44 is connected, and the flow of the eddy current of the braking drum 15 is spread in the axial direction to increase the braking force.

The guide cylinder 6 is constituted by connecting an end wall 6d made of an annular plate to a cylinder made of a nonmagnetic material having a C-shaped cross section, for example. The guide tube 6 is fixed to a non-rotating part, for example, a gear box of a transmission by a suitable means. Outer tube part 6a of guide tube 6
The ferromagnetic plate 31 having the retaining ridges 31a is coupled to a number of openings 32 provided at equal intervals in the circumferential direction. Preferably, the ferromagnetic plate 31 is cast when the guide tube 6 is formed by casting. The ferromagnetic plate 31 has a rectangular plate shape, and the plate surface is curved in an arc shape.

A movable magnet support cylinder 9 made of a magnetic material is provided in the inner space 20 of the guide cylinder 6 and is provided with a sliding bearing or roller bearing 3.
5 supports the inner cylinder 6b so as to be able to rotate forward and backward. The arm 34 extending in the axial direction from the magnet support cylinder 9 is connected to the rod of the actuator A via an arc-shaped slit 33 provided on the end wall 6c of the guide cylinder 6. The magnet support cylinder 9 is coupled to the outer peripheral surface of the magnet 8 facing the left half of each ferromagnetic plate 31 such that the polarity of each ferromagnetic plate 31 is alternately different in the circumferential direction. On the other hand, an immovable magnet support cylinder 9a made of a magnetic material is fixed to the inner cylinder section 6b at the inner space 20 of the guide cylinder 6, and a magnet 8a facing the right half of each ferromagnetic plate 31 is provided on the outer peripheral surface. ,
The ferromagnetic plates 31 are coupled such that their polarities alternately differ in the circumferential direction. A plurality of actuators A are coupled to the end wall 6c of the guide cylinder 6 at equal circumferential intervals. The actuator A has a piston 4 fitted in the cylinder 2, and a rod projecting from the piston 4 to the outside is connected to an arm 34.

As shown in FIG. 2, the inner surface and the outer surface of the magnet 8a of the magnet support cylinder 9a are cylindrical, and each magnet 8a
a between the stepped portion 26 formed at the end in the circumferential direction of FIG.
8 fastens to the magnet support cylinder 9a.

Next, the operation of the eddy current reduction device according to the present invention will be described. During non-braking, as shown in FIG. 1, the magnet 8 of the magnet support tube 9 and the magnet 8a of the magnet support tube 9a have opposite polarities to the ferromagnetic plate 31. At this time, the magnets 8 and 8a are connected to the respective ferromagnetic plates 31 and the magnet support cylinders 9 and
9a, a short-circuit magnetic circuit w is formed, and no magnetic field is applied to the braking drum 15. When the magnet A is turned by the actuator A from the non-braking position to the braking position shown in FIG. 2 by the actuator A by the arrangement pitch of the magnets 8, the magnets 8, 8 a arranged in the axial direction have polarities opposed to the ferromagnetic plates 31. And a magnetic field is applied to the braking drum 15 via the ferromagnetic plate 31. When the rotating brake drum 15 crosses the magnetic field, an eddy current flows through the brake drum 15 and the brake drum 15 generates a braking torque. At this time, each magnet 8, 8a is
And a magnetic circuit z between the magnet support cylinders 9 and 9a.

As shown in FIGS. 1 and 3, according to the present invention, annular bodies 41 and 42 made of a good conductor having an L-shaped cross section are provided at the open end or the left end of the brake drum 15, and the brake drum 15 is provided at the base end or the right end. The ring members 43 and 44 made of a conductor are connected to each other. The method of connecting the annular bodies 41 to 44 to the braking drum 15 is by welding, welding, plating, or the like. In particular,
It is preferable that nickel plating is applied to the end wall surface and the inner peripheral surface 15b of the braking drum 15 in advance, and the ring members 41 to 44 made of a good conductor are joined to the plating layer by brazing. With respect to the end wall surface of the braking drum 15 to which the support arm 16 is coupled, when an annular body 43 made of a good conductor is interposed between the support arm 16 and the braking drum 15, the coupling between the support arm 16 and the braking drum 15 is established. Since the force is weakened, the annular body 43 made of a good conductor is provided so as to be divided in the circumferential direction so as to remove the connecting portion between the support arm 16 and the braking drum 15. It is preferable to connect to the end wall surface by welding. Annular bodies 42 and 44 made of a good conductor
Is shifted to the same position as the edge of the ferromagnetic plate 31, or to the outside of the edge of the ferromagnetic plate 31, that is, toward the end wall surface.

As shown in FIGS. 3 and 4, an annular body 42 made of a good conductor is connected to the inner peripheral surface 15b of the braking drum 15.
Is inferior to the annular body 41 made of a good conductor bonded to the end wall surface 55, so that the thickness t2 of the annular body 42 made of a good conductor on the inner peripheral surface 15b is reduced by the thickness of the end wall surface 55. The heat capacity is increased by making the annular body 41 thicker than the thickness t1 of the annular body 41, and the density of the eddy current is reduced to suppress the temperature rise.

In order to enhance the cooling performance of the annular body 42 made of a good conductor, a number of axial grooves 45 are provided in the annular body 42 at intervals in the circumferential direction. The depth of the groove 45 is configured to gradually increase from the inner peripheral surface 15 b of the braking drum 15 to the end wall surface 55. It is preferable that the annular bodies 43 and 44 at the base end of the braking drum 15 be similarly configured. As shown in FIG. 5, instead of the groove 45 being tapered, the groove may have a substantially constant depth in the axial direction.

In the modified embodiment shown in FIGS. 6 and 7, the annular body 42 made of a good conductor has a tapered groove 45 and the annular body 41 made of a good conductor has a relatively shallow groove 46 in the radial direction. These are provided continuously with each other. By providing a large number of grooves 46, 45 at circumferential intervals in the annular bodies 41, 42 made of a good conductor, the annular bodies 41, 4 made of a good conductor are provided.
2 has a large surface area, and a portion without the grooves 46 and 45 functions as an impeller to guide the outside air to the inner peripheral surface 15b of the brake drum 15, thereby increasing the temperature at the end of the brake drum 15,
Particularly, the temperature rise of the annular bodies 41 and 42 is suppressed. Even if the eddy current at both ends of the braking drum 15 increases, the temperature rise at both ends of the braking drum 15 is suppressed, so that the annular bodies 41 to 44 made of a good conductor do not peel off from the braking drum 15. The braking ability is improved by the increase of the eddy current.

As shown in FIG. 8, if the grooves 45, 46 are inclined not in the radial direction of the braking drum 15, but in the radial direction, outside air is easily drawn inward along the grooves 46, 45. Thus, the inner peripheral surface 15b of the braking drum 15 is effectively cooled.

In the above embodiment, the inner space 20 of the guide cylinder 6
Accommodates a rotatable magnet support tube 9 and an immovable magnet support tube 9a, and the magnets 8, 8a are provided with a braking drum 15 and a magnet support tube 9,
9a and a non-braking position where the magnets 8 and 8a form a short-circuit magnetic circuit w between the ferromagnetic plate 31 and the magnet support cylinders 9 and 9a. Although the type of eddy current reduction device has been described, the present invention is not limited to this, and can be applied to an eddy current reduction device as shown in FIG.

In the embodiment shown in FIG. 9, the right half of the guide tube 6 faces the inside of the brake drum 15, and the left half of the guide tube 6 projects outside the brake drum 15. The guide cylinder 6 has a C-shaped cross section having an outer cylinder portion 6a, an end wall 6c, and an inner cylinder portion 6b made of a magnetic material, and an end wall 6d coupled with a bolt 12.
Further, the conical portion formed at the left end of the outer cylinder portion 14 formed from a thin plate is overlapped with the conical surface 30 of the outer cylinder portion 6a, and the right end portion of the outer cylinder portion 14 is bent inward in a radial direction and the end wall 6d is bent. And an inner space 20 having a rectangular cross section. An actuator A, which inserts the piston 4 into the cylinder 2 and separates the end chamber 3 and the end chamber 5, is connected to the end wall 6c of the guide cylinder 6, and a rod 7 projecting from the piston 4 to the inner space 20 is magnet-supported. It is connected to the cylinder 9. Brake drum 15
The left half outer cylindrical portion 6a protruding from the outer cylindrical portion is made of a thick magnetic body. The right half part of the guide cylinder 6, that is, the outer cylinder part 14 facing the inner peripheral surface 15b of the braking drum 15 is made of a thin plate made of a non-magnetic material, or further made of a ferromagnetic stainless steel thin plate, for example. Only the portion of the outer cylinder portion 14 not facing the outer surface of the magnet 8 is rapidly cooled from a high temperature state to a non-magnetic austenitic phase.

In this embodiment, similarly to the embodiment shown in FIG. 1, the annular body 4 made of a good conductor is
The annular bodies 42 and 44 made of a good conductor thicker than the annular bodies 41 and 43 are respectively coupled to the inner peripheral surface 15b. The inner ends of the annular bodies 42 and 44 made of a good conductor are arranged outside the both ends of the magnet 8 so as not to overlap with the outer surface of the magnet 8. In order to increase the thickness of the outer cylindrical portion 6a protruding to the outside of the braking drum 15, a conical surface 30 is formed at the end of the outer cylindrical portion 6a, and the open end of the braking drum 15 corresponds to the conical surface 30. The portion is also formed in a conical surface, and an annular body 41 made of a good conductor is connected to the conical surface.

When the magnet A is pulled out of the brake drum 15 by the actuator A during non-braking, each magnet 8 forms a short-circuited magnetic circuit facing the outer cylinder portion 6a of the guide cylinder 6, and Has no magnetic field. At the time of braking, when the magnet support cylinder 9 is protruded into the inside of the braking drum 15, the magnetic field from each magnet 8 passes through the outer cylinder part 14 and
Extends to 5. When the rotating brake drum 15 crosses the magnetic field from the magnet 8, an eddy current flows through the brake drum 15, and the brake drum 15 generates a braking torque.

In the embodiment shown in FIG. 9, the outer cylinder portion 14 facing the inner peripheral surface 15b of the braking drum 15 is made of a thin plate made of a non-magnetic material. The same operation and effect can be obtained even when the ferromagnetic plate 31 is coupled so as to face the outer surface of the magnet 8 (see FIG. 1).

[0023]

As described above, according to the present invention, the amount of eddy current generated in the braking drum is made by connecting the annular body made of a good conductor such as copper to both ends of the braking drum made of low carbon steel or the like. And the braking ability is improved. In particular, the annular body made of a good conductor bonded to the inner peripheral surface of the braking drum,
The heat capacity of the annular body made of a good conductor is increased by making it thicker than the annular body made of a good conductor bonded to the end wall surface of the braking drum, and the temperature rise of the annular body due to the Joule heat during braking is suppressed. . Further, by providing a large number of axial grooves in the annular body made of a good conductor at intervals in the circumferential direction, the surface area of the annular body made of a good conductor is increased,
In addition, since the outside air is introduced to the inner peripheral surface and the cooling performance of the annular body is enhanced, the temperature rise of the annular body made of a good conductor is suppressed also in this point, the braking capacity is enhanced, and the annular body is also improved. The durability against peeling and thermal cracking is improved.

[Brief description of the drawings]

FIG. 1 is a front sectional view of an eddy current reduction device according to the present invention.

FIG. 2 is a side sectional view of the eddy current reduction device.

FIG. 3 is an enlarged front sectional view showing a main part of the eddy current reduction device.

FIG. 4 is a side sectional view of the eddy current reduction device.

FIG. 5 is a front sectional view showing a main part of an eddy current reduction device according to a modified embodiment of the present invention.

FIG. 6 is a front sectional view showing a main part of an eddy current reduction device according to a modified embodiment of the present invention.

FIG. 7 is a side sectional view taken along line 7A-7A of FIG. 6;

FIG. 8 is a side view of an eddy current reduction device according to a modified embodiment of the present invention.

FIG. 9 is a front sectional view of another type of eddy current reduction device to which the present invention is applied.

[Explanation of symbols]

A: Actuator 2: Cylinder 4: Piston
6: Guide tube 6a: Outer tube portion 6b: Inner tube portion 6c: End wall 6d: End wall 8: Magnet 8
a: Magnet 9: Magnet support cylinder 9a: Magnet support cylinder 14:
Outer cylinder 15: Brake drum 16: Support arm 15b: Inner peripheral surface 20: Inner space 23: Brake drum 31: Ferromagnetic plate 34: Arm 41: Annular body 42: Annular body 43: Annular body 44: Annular body 45 : Groove 46: Groove 55: End wall

Claims (3)

[Claims] 1. A guide cylinder comprising a non-magnetic material having a braking drum made of a conductor coupled to a rotating shaft and a hollow portion having a rectangular cross section attached to a non-rotating part such as a vehicle body so as to face the inside of the braking drum. At least one rotatable magnet support cylinder housed in the inner space of the guide cylinder, a number of magnets coupled to the outer peripheral surface of the magnet support cylinder at equal intervals in the circumferential direction, An eddy current reduction device that has a ferromagnetic plate cast in opposition to each of the magnets in a cylindrical portion and generates a braking force based on an eddy current on the braking drum by a magnetic field from the magnet; An annular body made of a good conductor such as copper is connected to an end portion of the inner peripheral surface that does not face the ferromagnetic plate and an end wall surface of the braking drum. Also, the thickness of the annular body on the inner peripheral surface of the braking drum was increased. Eddy current reduction apparatus according to claim. 2. A guide drum having a braking drum made of a conductor coupled to a rotating shaft, and a hollow section having a rectangular cross section attached to a non-rotating part of a vehicle body or the like such that a half part faces the inside of the braking drum. A magnet support cylinder accommodated in the inner space of the guide cylinder so as to be movable in the axial direction, a number of magnets coupled to the outer peripheral surface of the magnet support cylinder at equal circumferential intervals, and the braking of the outer cylinder part of the guide cylinder A portion made of a magnetic material that does not face the inner circumferential surface of the drum, and a portion of the outer tube portion of the guide tube made of a non-magnetic material that faces the inner circumferential surface of the braking drum and faces the magnets. An eddy current reduction device having a ferromagnetic plate and generating a braking force based on an eddy current on the braking drum by a magnetic field from the magnet; an end of an inner peripheral surface of the braking drum not facing the ferromagnetic plate; And the end wall of the braking drum Combining annular body made of a conductor, an eddy current reduction apparatus characterized by the annular body of the end wall of the brake drum to increase the thickness of the annular body of the inner peripheral surface of the brake drum. 3. The eddy current reduction device according to claim 1, wherein a number of axial grooves are provided at equal intervals in a circumferential direction in an annular body on an inner peripheral surface of said braking drum.