JPH0727830Y2 - Eddy current trigger - Google Patents

Description

[Detailed Description of Device] a. Purpose of the Invention (Industrial field of application) The present invention arranges a rotating body made of a ferromagnetic material so as to cross a magnetic flux generated from an electromagnet, and brakes the rotation of the rotating body by an eddy current generated in the rotating body. The present invention relates to an eddy current brake that is configured to generate a torque that operates.

(Prior Art) An example of an eddy current brake that has been conventionally used is shown in FIG. In this brake,
Bearings 58a, 58b in a fixed housing 55 that is fixedly held
The shaft 54 is rotatably supported via the. shaft
Flange couplings 52 and 53 are spline-coupled and attached to both ends of 54, and a rotary drum 51 is coupled to one coupling 52. The flange couplings 52, 53 are connected to a rotating shaft (not shown) to be braked.

On the other hand, a cylindrical bracket 56 is coupled to the fixed housing 55, and a plurality of electromagnets 60 are radially fixed on the outer peripheral surface of the bracket 56 at substantially equal intervals. This electromagnet 60
Is a prismatic core member 61 made of a ferromagnetic material such as iron and having a rectangular cross section, and a coil wound around the core member 61.
62 and is fixed to the bracket 56 by the bolt 63. The core shaft of the core member 61 is arranged so as to extend in the radial direction, and the outer end surface 61a of the core member 61 closely faces and faces the cylindrical inner surface 51a of the rotary drum 51. For this reason, when the coil 62 is energized, the magnetic flux of the electromagnet 60 extends across the cylindrical portion of the rotating drum 51 along the column axis of the core member 61, whereby the rotating drum 51.
Eddy current is generated in the cylindrical part of. The rotating drum 51 is the shaft
Since it is connected to a rotating shaft (not shown) via 54 and the flange couplings 52, 53, when the rotating drum 51 is rotated by the rotation of the rotating shaft, the rotating direction of the rotating drum 51 is opposite to that of the rotating drum 51 due to the action of the eddy current. Braking torque is applied.

(Problems to be Solved by the Invention) When the rotation of the rotary shaft is braked by the eddy current braking device having the above configuration, the eddy current generating portion of the rotating drum 51 generates heat, and this portion becomes hot. This heat is generated by the rotating drum 51.
Occurs in a portion where the end surface 61a of the core member 61 of the electromagnet 60 in, ie, a portion indicated by a width l in the figure, is generated when a large braking is performed by this brake or when a long braking is performed. There is a problem that the portion indicated by the width 1 becomes high temperature red heat, and there is a problem that thermal distortion may occur at this portion due to the high temperature.

It is considered that if the core member 60 is thickened so that the area of the end face 61a of the core member 60 is increased and the width 1 is increased, the heat generation portion can be diffused and the temperature rise can be prevented.
If the thickness of 60 is made thick, the density of the magnetic flux to be generated in this portion becomes small, the generated braking torque becomes small, and there is a problem that the desired braking ability cannot be obtained.

The present invention has been made in view of the above problems, and has an eddy-current braking gas structure that can suppress a temperature rise of a rotating body due to heat generated by an eddy current to a low level without reducing a generated braking torque. The purpose is to provide.

B. Configuration of the Invention (Means for Solving the Problem) In order to achieve this object, in the eddy current brake according to the present invention, the columnar portion and the end of the columnar portion are integrally connected and bifurcated and extended. Using a core member formed in a Y shape from the bifurcated portion, a coil is wound around the columnar portion to form an electromagnet, and the columnar portion and the bifurcated portion are located in the same plane including the rotation axis of the rotating body. An electromagnet is arranged so that the end surface closely faces the surface of the rotating body. In this case, the core member is formed so that the area (A) of the cross section perpendicular to the axis of the columnar part is substantially equal to the sum (2B) of the areas (B) of the cross sections perpendicular to the extension direction of the bifurcated part. Is preferred.

(Operation) When the eddy current brake having the above-mentioned configuration is used, the magnetic flux generated in the columnar portion when the coil is energized passes through the bifurcated portion and crosses the surface of the rotating body facing the end face of the bifurcated portion. With this configuration, the magnetic flux is divided into right and left at the bifurcated portion and spreads and crosses the rotating body, so that a local heat generating portion of the rotating body is diffused and the temperature rise of the rotating body is suppressed. Even in this case, the cross-sectional area of the columnar portion is the same as the conventional one, and the magnetic flux density generated in this portion does not decrease, and the desired braking torque is secured. In order to prevent the magnetic flux from being weakened by being diffused or squeezed when passing through the bifurcated portion, the cross-sectional area (A) of the columnar portion is set to the cross-sectional area (B) perpendicular to the extension direction of the bifurcated portion. It is desirable to make it equal to the sum (2B).

(Embodiment) Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

First, FIG. 1 shows an eddy current brake according to the present invention, and FIG. 2 shows a cross section taken along the arrow II-II in this figure.

This eddy current brake is basically a fixed housing 5 fixed to a base 20 and fixedly held, a bracket 6 fixed to the fixed housing 5, a plurality of electromagnets 10 mounted on the bracket 6, and the like. Section, a shaft 4 rotatably held in a fixed housing 5 through bearings 8a, 8b, flange couplings 2, 3 connected to both ends of the shaft 4, and a rotary drum 1 connected to the flange coupling 2. And a rotating part including

The bracket 6 that constitutes the fixed portion has a cylindrical ring-shaped portion, and eight electromagnets 10 are radially attached to the outer peripheral surface 6a of the ring-shaped portion at substantially equal intervals by bolts 17. The electromagnet 10 includes a core member 11 made of a ferromagnetic material such as iron, and a coil 15 wound around the core member 11.
Composed of and.

This core member 11 is enlarged and shown in FIG. 3, and as shown in the drawing, the core member 11 includes a columnar portion 12 and a bifurcated portion 13 extending upward from the columnar portion 12 and viewed from the front side. It is formed in a letter shape. The columnar portion 12 has a rectangular cross section perpendicular to the axis, that is, a rectangular columnar shape, and has a width dimension a and a thickness dimension t.
Is. A forked portion 13 is integrally connected to the upper end of the columnar portion 12, and a cross section of the forked portion 13 at a right angle to the extension direction is also rectangular. The width of each bifurcated portion 13 in the extending direction is b.
The thickness dimension is t like the columnar portion 12. For this reason,
The area A of the cross section of the columnar portion 12 perpendicular to the axis A = a × t,
The area B of the cross section perpendicular to the extension direction of 13 is B = b × t. Further, an upper end surface 13a cut at a right angle to the axis of the columnar portion 12 is formed on the upper end of the bifurcated portion 13. The coil 15 is wound around the columnar portion 12. Electromagnet configured in this way
The columnar portion 12 and the bifurcated portion 13 of the core member 11 are attached to the bracket 6 so that the columnar portion 12 and the bifurcated portion 13 are positioned in the same plane P including the rotation axis S of the rotating drum 1 (shaft 4). There is.

On the other hand, the flange couplings 2 and 3 are concentrically connected to both ends of the shaft 4 constituting the rotating portion by splines 4a and 4b, and the inner peripheral end 1c of the rotating drum 1 is connected to the flange coupling 2. It is bolted. Rotating drum 1
The inner peripheral surface 1a of the cylindrical portion of is disposed so as to cover the electromagnet 10, and in this state, the upper end surface of the forked portion 13 of the core member 11
13a is located in close proximity to the inner peripheral surface 1a of the rotary drum 1. A plurality of heat radiation fins 1d are formed on the outer periphery of the cylindrical portion of the rotary drum 1. Further, a plurality of heat radiation fins for radiating the high temperature air inside are radially penetrated through the center of the cylindrical portion. The hole 1b is formed.

In the eddy current brake configured as described above, the flange couplings 2 and 3 are connected to a rotating shaft (not shown), and the rotating portion rotates with this rotating shaft. In this state, the coil 15 of the electromagnet 10 is energized to activate the eddy current brake and brake the rotation of the rotating shaft. When the coil 15 is energized, a magnetic flux is generated in the columnar portion 12 in the axial direction, the magnetic flux flows along the bifurcated portion 13 in the extension direction thereof, and crosses the cylindrical portion of the rotary drum 1 from the upper end surface 13a. Therefore, an eddy current is generated in the cylindrical portion of the rotating drum 1, and the action of this eddy current generates a braking torque opposite to the rotating direction of the rotating drum 1 to brake the rotating shaft.

Here, the place where the eddy current is generated in the rotating drum 1 is
A portion where the magnetic flux crosses, that is, a portion where the upper end surface 13a of the bifurcated portion 13 faces each other, and a portion where heat is generated by this eddy current is a portion indicated by a width L in FIG. This width L is larger than the width of the columnar portion 12 and larger than the width 1 of the conventional heat generating portion shown in FIG. Therefore, when the cross-sectional area A perpendicular to the axis of the columnar portion 12 and the coil 15 are equal to the columnar portion 61 and the coil 62 of the conventional brake (FIG. 5), the width of the heat generating portion is wider in this example ( L> l), the heat is diffused, so that the temperature of the heat generating portion in the rotary drum 1 becomes lower than in the conventional case. That is, as long as the cross-sectional area A of the columnar portion 12 and the performance of the coil 15 are equal, the magnetic flux density generated in the columnar portion 12 is the same, and the amount of heat generated by the eddy current generated in the rotating drum is the same in both the conventional case and this example. Although it is the same, since the width (area) of the heat generating portion is larger in this example, the brake of this example diffuses the heat generation and prevents the temperature from rising locally. As a result, it is possible to prevent the heat generation portion of the rotating drum 1 from becoming hot red and causing thermal distortion.

Since the magnetic flux density generated in the columnar portion 12 is the same as the conventional one, the braking force obtained as long as this magnetic flux traverses the rotary drum 1 is the same as the conventional one, and the braking ability is not lowered. However, it is necessary to prevent the magnetic flux generated in the columnar portion 12 from decreasing in the bifurcated portion 13, and from this point,
It is desirable that the area A of the cross section perpendicular to the axis of the columnar portion 12 be substantially equal to the sum (= 2B) of the areas B of the cross sections of the bifurcated portion 13 perpendicular to the extending direction.

In the above, the example in which the rotating drum is cylindrical and the electromagnets 10 are radially arranged is shown, but the eddy current brake according to the present invention is not limited to such a structure, and for example,
The configuration may be as shown in FIG.

In this brake, in the fixing member 35, the bearings 38a, 38a
The shaft 34 is rotatably supported via b. Flange couplings 32 and 33 and rotating disks 31 and 31 are connected to both ends of the shaft 54. On both sides of the fixing member 35, a plurality of electromagnets are arranged on the circumference at substantially equal intervals.
10 is fixed. This electromagnet 10 is the same as the above-mentioned electromagnet, and the columnar portion 12 and the forked portion 13 of the core member 11 include the same plane P including the rotation axis S of the rotating disk 31 (shaft 34).
The end face 13a of the forked portion 13 of the core member 11 is attached to the bracket 6 with its orientation determined so as to be located inside.
Are arranged in close proximity to the inner end surface 31a of the rotating disk 31. Even in the case of an eddy current brake with such a configuration,
The width L of the portion where the eddy current is generated and heat is generated is wider than before.
Since the heat generation is diffused, it is possible to prevent the heat generation part from locally increasing in temperature.

C. EFFECTS OF THE INVENTION As described above, according to the present invention, a core member formed in a Y-shape is formed from a columnar portion and a bifurcated portion which is integrally connected to an end portion of the columnar portion and is branched into two forks. A coil is wound around the pillar to form an electromagnet, and this electromagnet is arranged so that the end face of the forked portion closely faces the surface of the rotating body. Since the generated magnetic flux is divided into left and right at the bifurcated part and spreads across the rotating body, the heat generating part of the rotating body is diffused and the temperature rise of the rotating body can be suppressed. Can be prevented. Moreover, even in this case, the cross-sectional area of the columnar portion is the same as the conventional one, and the magnetic flux density generated in this portion does not decrease, and the desired braking torque can be secured.

[Brief description of drawings]

FIG. 1 is a side view showing an example of an eddy current brake according to the present invention, FIG. 2 is a sectional view of the eddy current brake taken along arrow II-II, and FIG. FIG. 4 is a side view showing a core member of an electromagnet used, FIG. 4 is a schematic sectional view showing another example of the eddy current brake according to the present invention, and FIG. 5 is a sectional view showing a conventional eddy current brake. DESCRIPTION OF SYMBOLS 1 ... Rotating drum, 4 ... Shaft 6 ... Bracket, 10 ... Electromagnet 11 ... Core member, 12 ... Columnar part 13 ... Bifurcated part, 15 ... Coil

Claims (2)

[Scope of utility model registration request] 1. A rotating body formed of a ferromagnetic material and an electromagnet, wherein the rotating body is arranged so as to cross a magnetic flux generated from the electromagnet, and an eddy current generated in the rotating body causes the rotating body to rotate. In an eddy current brake configured to brake rotation, a core member forming the electromagnet is integrally connected to a columnar portion around which a coil is wound and an end portion of the columnar portion, and a bifurcated portion bifurcated and extended. And Y-shaped, the columnar portion and the bifurcated portion are located in the same plane including the rotation axis of the rotating body, and the end face of the bifurcated portion is closely faced to the surface of the rotating body and the electromagnet is formed. An eddy current braking device characterized by being provided with. 2. The area (A) of the cross section perpendicular to the axis of the columnar portion is
2. The eddy current brake according to claim 1, wherein the core member is formed so as to be substantially equal to a sum (2B) of areas (B) of respective cross sections perpendicular to the extension direction in the bifurcated portion.