EP3934381B1

EP3934381B1 - Induction heated roll apparatus

Info

Publication number: EP3934381B1
Application number: EP21182691.2A
Authority: EP
Inventors: Takatsugu Kitano
Original assignee: Tokuden Co Ltd Kyoto
Current assignee: Tokuden Co Ltd Kyoto
Priority date: 2020-07-03
Filing date: 2021-06-30
Publication date: 2022-08-10
Anticipated expiration: 2041-06-30
Also published as: JP2022013229A; EP3934381A1; JP7437762B2

Description

BACKGROUND

TECHNICAL FIELD

The present invention relates to an induction heated roll apparatus.

Related Art

Conventionally, as disclosed in Patent Literature 1, an induction heated roll apparatus includes a cylindrical roller that is rotatable and a cylindrical iron core, and an induction coil is wound around the cylindrical iron core and disposed inside the cylindrical roller. The induction heated roll apparatus is provided with a cooling structure for cooling the cylindrical iron core or the induction coil.
In this cooling structure, a hollow strip is spirally provided on an inner peripheral surface of the cylindrical iron core, and an inlet/outlet of a cooling medium is provided at one end side of the cylindrical roller. Specifically, an introduction pipe is connected to one end of the hollow strip, a lead-out pipe is connected to the other end of the hollow strip, a cooling medium is supplied from the introduction pipe, and the cooling medium is discharged from the lead-out pipe.
However, since the lead-out pipe connected to the other end of the hollow strip cannot penetrate the hollow strip, it is necessary to shift the lead-out pipe toward an inner periphery or an outer periphery (for example, in the iron core) with respect to the hollow strip, and a piping structure becomes complicated, or the lead-out pipe cannot be disposed in relation to a surrounding structure in some cases.

Prior Art Document

Patent Document

Patent Document 1: JP 3756261 B2

SUMMARY

Therefore, the present invention has been made to solve the above problems, and a main object thereof is to simplify a piping structure of a cooling pipe for cooling a cylindrical iron core.
That is, an induction heated roll apparatus according to the present invention includes a roller main body that is rotatably supported, a cylindrical iron core provided inside the roller main body, an induction coil wound around an outer peripheral surface of the cylindrical iron core, and a cooling pipe welded to an inner peripheral surface of the cylindrical iron core, in which the cooling pipe includes an outward pipe and a return pipe spirally wound in a same winding direction along the inner peripheral surface of the cylindrical iron core, the outward pipe and the return pipe communicate with each other at one end side, a cooling medium inlet is formed at another end of the outward pipe, and a cooling medium outlet is formed at the other end of the return pipe.
In such an induction heated roll apparatus, when the cooling medium is introduced into the cooling pipe from the cooling medium inlet, the cooling medium flows through the outward pipe, then flows through the return pipe connected to the outward pipe, and is led out from the cooling medium outlet. Here, since both the outward pipe and the return pipe are spirally wound in the same winding direction along the inner peripheral surface of the cylindrical iron core, the cooling pipe can be disposed along the inner peripheral surface of the cylindrical iron core from the cooling medium inlet to the cooling medium outlet. As a result, a piping structure of the cooling pipe for cooling the cylindrical iron core can be simplified. In addition, since the cooling medium can be introduced and led out in a configuration in which the cooling pipe runs along the inner peripheral surface of the cylindrical iron core, a space occupied by the cooling pipe can be reduced. Further, since the outward pipe and the return pipe of the cooling pipe are not provided in the thickness of the iron core, it is possible to prevent a decrease in a cross-sectional area of the iron core.
Examples of the induction heated roll apparatus include a single-sided support type (cantilever type). Specifically, the roller main body has a bottomed cylindrical shape, the induction heated roll apparatus further includes a rotary shaft connected to a bottom central portion of the roller main body and provided along a rotation center axis of the roller main body inside the roller main body, and the rotary shaft is inserted into the cylindrical iron core, while the cylindrical iron core is disposed in a hollow space between the roller main body and the rotary shaft.
In such a single-sided support type (cantilever type) induction heated roll apparatus, in addition to the arrangement of the rotary shaft inside the roller main body, a space between the rotary shaft and the roller main body, in which the cylindrical iron core is disposed is narrowed due to a reduction in diameter of the roller main body, and the like. In order to suitably cool a cylindrical iron core disposed in such a narrow space, it is desirable to have a configuration including an outward pipe and a return pipe spirally wound in the same winding direction along the inner peripheral surface of the cylindrical iron core as in the present invention.
Specifically, when a distance between the inner peripheral surface of the cylindrical iron core and the outer peripheral surface of the rotary shaft is equal to or greater than the one cooling pipe and less than two of the cooling pipes, an effect of the configuration of the cooling pipe of the present invention becomes remarkable.
In order to uniformly cool the cylindrical iron core as a whole over the axial direction, it is desirable that the outward pipe and the return pipe are wound at a same pitch.
Specifically, it is conceivable that a spiral element of the forward pipe and a spiral element of the return pipe adjacent to each other are equidistant from each other. In addition, it is conceivable that the spiral element of the outward pipe and the spiral element of the return pipe are in contact with each other.
According to the present invention configured as described above, since the cooling pipe has the outward pipe and the return pipe spirally wound in the same winding direction along the inner peripheral surface of the cylindrical iron core, it is possible to simplify the piping structure of the cooling pipe for cooling the cylindrical iron core.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view schematically illustrating a configuration of an induction heated roll apparatus according to an embodiment of the present invention;
FIG. 2 is a perspective view of a cooling pipe according to the embodiment; and
FIG. 3 is a modification of the cooling pipe.

DETAILED DESCRIPTION

Hereinafter, an embodiment of an induction heated roll apparatus according to the present invention will be described with reference to the drawings.

1. Apparatus Configuration

An induction heated roll apparatus 100 according to the present embodiment is a so-called single-sided support type (cantilever type), and includes a roller main body 2 and a magnetic flux generation mechanism 3 provided inside the roller main body 2 as illustrated in FIG. 1.
The roller main body 2 has a bottomed cylindrical shape, and a rotary shaft 4 is connected to the bottom central portion of the roller main body. The rotary shaft 4 is provided along a rotation center axis of the roller main body 2 inside the roller main body 2, and is rotatably supported by a machine (not illustrated) via bearings 5 such as rolling bearings outside the roller main body 2. Since the rotary shaft 4 is rotatably supported, the roller main body 2 is also rotatably supported. Note that the rotary shaft 4 is rotated by a motor (not illustrated).
The magnetic flux generation mechanism 3 includes a cylindrical iron core 31 and an induction coil 32 wound around an outer peripheral surface of the cylindrical iron core 31. The cylindrical iron core 31 is formed by radially arranging and stacking iron core steel plates having curved portions. The curved portion has, for example, an involute shape. The rotary shaft 4 is inserted into the cylindrical iron core 31, while the cylindrical iron core is disposed in a hollow space between the roller main body 2 and the rotary shaft 4. An AC power supply (not illustrated) is connected to a lead wire L1 of the induction coil 32. The magnetic flux generation mechanism 3 is supported by a flange member 6 fixed to a machine base.
When an AC voltage is applied to the induction coil 32 by such a magnetic flux generation mechanism 3, an alternating magnetic flux is generated, and the alternating magnetic flux passes through a cylindrical portion (shell portion) of the roller main body 2. By this passage, an induced current is generated in the shell portion, and the shell portion generates Joule heat by the induced current. In order to improve temperature uniformity in the shell portion, a jacket chamber in which a gas-liquid two-phase heating medium is sealed may be formed in the shell portion.
The induction heated roll apparatus 100 according to the present embodiment includes a cooling pipe 7 that is provided inside the roller main body 2 and cools the cylindrical iron core 31 and the induction coil 32. Note that a cooling medium such as cooling water is supplied from a cooling medium supply source (not illustrated) to the cooling pipe 7.
Specifically, the cooling pipe 7 is welded to the inner peripheral surface of the cylindrical iron core 31, and includes an outward pipe 71 and a return pipe 72 spirally wound in a same winding direction along an inner peripheral surface of the cylindrical iron core 31. The cooling pipe 7 of the present embodiment is configured using a circular pipe, and includes one outward pipe 71 and one return pipe 72. Note that the cooling pipe 7 desirably has heat resistance and is made of a nonmagnetic material, and for example, stainless steel can be used.
As particularly shown in FIG. 2, the outward pipe 71 and the return pipe 72 communicate with each other at one end side, a cooling medium inlet P1 is formed at the other end of the outward pipe 71, and a cooling medium outlet P2 is formed at the other end of the return pipe 72. The cooling medium inlet P1 and the cooling medium outlet P2 are provided on the opening side of the roller main body 2, and here, the cooling medium inlet P1 and the cooling medium outlet P2 penetrate the flange member 6 and are located on the machine base-side.
The outward pipe 71 and the return pipe 72 are wound at the same pitch, and a spiral element of the outward pipe 71 and a spiral element of the return pipe 72 adjacent to each other are configured to be equidistant from each other. In addition, the spiral element of the outward pipe 71 and the spiral element of the return pipe 72 are alternately arranged along the axial direction of the roller main body 2.
In the cooling pipe 7 of the present embodiment, the one outward pipe 71 and the one return pipe 72 communicating with each other at the one end side are formed by bending one pipe into a U-shape and then spirally bending the pipe. As a method of welding the cooling pipe 7 configured as described above to the inner peripheral surface of the cylindrical iron core 31, by inserting a linear filler material into the gap between the cylindrical iron core 31 and the cylindrical cooling pipe 7 and welding them, the welding between the cylindrical iron core 31 and the cooling pipe 7 can be strengthened, and a heat transfer area can be increased.
In the induction heated roll apparatus 100 of the present embodiment, the distance W (see FIG. 1) between the inner peripheral surface of the cylindrical iron core 31 and the outer peripheral surface of the rotary shaft 4 is equal to or greater than the one cooling pipe 7 and less than two of the cooling pipes 7, and the cooling pipe 7 having the above-described two-pipe configuration can be easily provided between the inner peripheral surface of the cylindrical iron core 31 and the outer peripheral surface of the rotary shaft 4 without efforts. In addition, since the distance between the cooling pipe 7 and the rotary shaft 4 is short, the rotary shaft 4 heated by heat from the roller main body 2 can be cooled, the bearings 5 that rotatably supports the rotary shaft 4 can be prevented from becoming high temperature, and thermal deterioration of the bearings 5 can be prevented.

2. Effects of Present Embodiment

In the induction heated roll apparatus 100 according to the present embodiment configured as described above, when the cooling medium is introduced from the cooling medium inlet P1 into the cooling pipe 7, the cooling medium flows through the outward pipe 71, then flows through the return pipe 72 connected to the outward pipe 71, and is led out from the cooling medium outlet P2. Here, since both the outward pipe 71 and the return pipe 72 are spirally wound in the same winding direction along the inner peripheral surface of the cylindrical iron core 31, the cooling pipe 7 can be disposed along the inner peripheral surface of the cylindrical iron core 31 from the cooling medium inlet P1 to the cooling medium outlet P2. As a result, the piping structure of the cooling pipe 7 for cooling the cylindrical iron core 31 can be simplified. In addition, since the cooling medium can be introduced and led out in the configuration in which the cooling pipe 7 is disposed along the inner peripheral surface of the cylindrical iron core 31, an occupied space by the cooling pipe 7 can be reduced. Further, since the outward pipe 71 and the return pipe 72 of the cooling pipe 7 are not provided in the thickness of the iron core 31, it is also possible to prevent a decrease in the cross-sectional area of the iron core 31.

3. Other Effects of Present Embodiment

Note that the present invention is not limited to the above embodiment.
For example, the cooling pipe 7 of the above embodiment has a configuration including one outward pipe 71 and one return pipe 72, but may have a configuration including two or more outward pipes and two or more return pipes. In this case, the cooling medium inlets of the two or more outward pipes may be independently provided in each of the outward pipes, or the cooling medium may be branched from one cooling medium inlet to be introduced into the two or more outward pipes. Similarly, the cooling medium outlets of the two or more return pipes may be independently provided in each of the return pipes, or the two or more return pipes may be joined and led out from one cooling medium outlet.
In addition, as illustrated in FIG. 3, the spiral element of the outward pipe 71 and the spiral element of the return pipe 72 may be configured to be in contact with each other.
Furthermore, in the above embodiment, the outward pipe 71 and the return pipe 72 are integrally formed by deforming one pipe, but the outward pipe 71 and the return pipe 72 may be communicated with each other by connecting a spiral pipe to be the outward pipe 71 and a spiral pipe to be the return pipe 72 at one end thereof using a connecting pipe or the like.
In addition, the cooling pipe of the above embodiment is a circular pipe having a circular cross-section, but may be an elliptical pipe having an elliptical cross-section or a rectangular pipe having a rectangular cross-section.
A heat insulating material may also be disposed on an outer periphery of the induction coil 32. This heat insulating material blocks a heat flow such as heat radiation and air heat conduction from the roller main body 2 to the induction coil 32, and contributes to lowering the temperature of the induction coil 32.
Furthermore, the cylindrical iron core 31, the induction coil 32, and the cooling pipe 7 may be molded with a heat-resistant resin. Specifically, when the gap between the cylindrical iron core 31, the induction coil 32, and the cooling pipe 7 is impregnated with a heat-resistant resin and molded, the air layer present in each portion is eliminated by filling with the heat-resistant resin, and the overall heat transfer coefficient is increased, the void portion of the magnetic flux generation mechanism 3 is eliminated, the thermal resistance is further reduced, and the heat of the cylindrical iron core 31 and the induction coil 32 can be effectively transferred to the cooling medium flowing through the cooling pipe 7.
In addition, in the above embodiment, an example in which the present invention is applied to a single-sided support type (cantilever type) induction heated roll apparatus has been described, but the present invention may be applied to a double-sided support type induction heated roll apparatus. In this case, the roller main body includes a cylindrical shell portion and a pair of journals provided at both ends of the shell portion. The journal portion includes a flange portion covering an end opening of the shell portion, and a hollow drive shaft integrally formed with the flange portion. The drive shaft is rotatably supported by the machine base via bearings such as rolling bearings, and is configured to be rotated by a driving force applied from the outside by, for example, a motor. The magnetic flux generation mechanism of the embodiment described above is disposed inside the roller main body.

Reference Signs List

100: induction heated roll apparatus
2: roller main body
31: cylindrical iron core
32: induction coil
4: rotary shaft
7: cooling pipe
71: outward pipe
72: return pipe
P1: cooling medium inlet
P2: cooling medium outlet

Claims

An induction heated roll apparatus (100) comprising:
a roller main body (2) that is rotatably supported;

a cylindrical iron core (31) provided inside the roller main body;

an induction coil (32) wound around an outer peripheral surface of the cylindrical iron core;

a cooling pipe (7) welded to an inner peripheral surface of the cylindrical iron core,

characterised in that the cooling pipe includes an outward pipe (71) and a return pipe (72) spirally wound in a same winding direction along the inner peripheral surface of the cylindrical iron core, the outward pipe and the return pipe communicate with each other at one end side, a cooling medium inlet (P1) is formed at another end of the outward pipe, and a cooling medium outlet (P2) is formed at another end of the return pipe.
The induction heated roll apparatus according to claim 1, wherein
the roller main body has a bottomed cylindrical shape,

the induction heated roll apparatus further comprises a rotary shaft (4) connected to a bottom central portion of the roller main body and provided along a rotation center axis of the roller main body inside the roller main body, and

the rotary shaft is inserted into the cylindrical iron core, while the cylindrical iron core is disposed in a hollow space between the roller main body and the rotary shaft.
The induction heated roll apparatus according to claim 2, wherein a distance between the inner peripheral surface of the cylindrical iron core and the outer peripheral surface of the rotary shaft is equal to or greater than the one cooling pipe and less than two of the cooling pipes.
The induction heated roll apparatus according to any one of claims 1 to 3, wherein the outward pipe and the return pipe are wound at a same pitch.
The induction heated roll apparatus according to claim 4, wherein a spiral element of the outward pipe and a spiral element of the return pipe adjacent to each other are equidistant from each other.
The induction heated roll apparatus according to claim 4, wherein the spiral element of the outward pipe and the spiral element of the return pipe are in contact with each other.