JPH1187029A - Annular metal body inductive heating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an annular metal body inductive heating apparatus capable of uniformly heating an annular metal body to a set temperature and easily inserting the body into a shaft without any fail at a maintenance site or the like. SOLUTION: In this annular metal body inductive heating apparatus, a metal plate 9 is disposed on the upper side of a ceramic plate 8 placed upwardly of a heating coil 1 of an inductive heater, a temperature detecting element 11 is embedded from a lower face at a position corresponding to the center of the heating coil 1 of the metal plate 9, a fixing metal fitting 12 comprised of a thin plate and having an expandable structure is securely mounted at the end of the metal plate 9, an annular metal body 13 is further loaded on the upper face of the metal plate 9, a control part 2 receives output of the temperature detecting element 11, and controls output to the heating coil 1 so that the metal plate 9 is at a set temperature, and the annular metal body 13 is heated to a given temperature by the conductive heat and radiation heat from the metal plate 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of mounting a ring-shaped metal body such as a steel wheel such as a bearing or a gear or a pulley on a ring-shaped metal body by heating the ring-shaped metal body and utilizing thermal expansion to make a predetermined diameter small. The present invention relates to a ring-shaped metal body induction heating device used at a maintenance site or the like in order to insert it into a shaft after increasing its size.

[0002]

2. Description of the Related Art Conventionally, when mounting a ring-shaped metal body such as a bearing or a steel wheel, the following method or a ring-shaped metal is used as a simple type which can be easily moved at a maintenance site or the like. It had been heated by a body heating device.

[0003] There is a method in which a metal plate is provided on a gas burner or an electric heater, and an annular metal body (for example, a bearing) to be heated is placed on the metal plate for heating. Inevitably, if there is insufficient experience, there is a problem that mounting cannot be performed due to insufficient heating, or excessive heating occurs. If the oil seal type bearing is overheated, oil flows out and the bearing becomes unusable.

[0004] There is a method in which a container containing oil such as machine oil is placed on a gas stove or an electric stove, and a ring-shaped metal body is put in the heated oil to heat the oil. However, odor is generated because the oil is heated. In addition, there is a problem that it is difficult to treat hot oil after the work is finished, and that oil such as a machine oil for heating adversely affects the oil of the bearing in the oil seal type bearing.

As shown in FIG. 6, a heating element such as a sheath heater a is disposed on the back side of the metal plate 9, and a temperature detecting element (not shown) for controlling temperature is disposed at an appropriate position. An annular metal body heating device including a hot plate dedicated to bearing heating for controlling the temperature to a predetermined temperature and setting an annular metal body (for example, a bearing) 13 placed on the metal plate 9 to a set temperature is also commercially available. This method has the merit that it can be controlled to the set temperature as compared with the above two methods, but has problems such as a large heat capacity, a long time to rise, overshoot to the set temperature, and large temperature unevenness. ,Also,
Oil-sealed bearings have the problem of overheating and oil spill.

As shown in FIG. 7, a pair of upper and lower cores for induction heating and a rod-shaped core for magnetically connecting the cores are penetrated through a hole in the center of an annular metal body (for example, a bearing) 13 to induce induction. A ring-shaped metal body induction heating device for heating has been invented (Japanese Patent Application Laid-Open No. 8-257843, Japanese Utility Model Application Laid-Open No. 6-1).
No. 5294). This method can shorten the rise time as compared with the method using a heating element such as a sheathed heater, and is the most suitable among the above four methods.

[0007]

In the above-mentioned conventional heating device for an annular metal body, even in a system in which the annular metal body is formed of an inner ring and an outer ring, even in the most suitable system of penetrating a rod-shaped core for induction heating, Since the inner ring is heated, there is a problem that the expansion ratio of the inner ring is larger than that of the outer ring and a metal ball located between the inner ring and the outer ring is pressed, which is not preferable as a heating method of the bearing. In addition, it is necessary to change the shape and dimensions of the rod-shaped core according to the type and size of the annular metal body. Was inconvenient.

An object of the present invention is to provide a ring-shaped metal body induction heating apparatus which can solve these problems.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has an annular metal body placed on a metal plate uniformly heated to a predetermined temperature by induction heating.
This is a ring-shaped metal body induction heating apparatus that can be heated to a set temperature without excess or shortage and can easily insert a ring-shaped metal body into a shaft without failure at a maintenance site or the like.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a heating coil, a control section for controlling a high-frequency current supplied to the heating coil and controlling the entire apparatus, and an operation section including various input operation means and display means. A metal plate made of a magnetic material is placed above the ceramic plate placed above the heating coil of the induction heater provided, and a temperature detector connected to the control unit from the lower surface at a position corresponding to the center of the heating coil of the metal plate Bury the element,
A metal fitting is provided at an end of the metal plate to fix the metal plate, and an annular metal body as a body to be heated is placed on the upper surface of the metal plate.

With the above arrangement, the temperature of the metal plate is detected by the temperature detection element, and the control unit receives the output of the temperature detection element and sets the metal plate to a predetermined temperature determined by an experiment in advance so that the annular metal body has a predetermined temperature. The output to the heating coil is controlled so that the annular metal body is heated to a predetermined temperature without overshooting by conduction heat and radiant heat from the metal plate, and the diameter is suitable for mounting to the shaft using thermal expansion. The size can be increased by a minute predetermined dimension.

Further, by providing the metal plate fixing metal so as to have a telescopic structure, thermal expansion and contraction of the metal plate can be absorbed.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view showing a schematic structure of an annular metal body induction heating apparatus according to one embodiment of the present invention.
3 is a perspective view of the same, and FIG. 3 and FIG.
FIG. 5 is a temperature distribution diagram of the object to be heated when the ring-shaped metal body induction heating device starts heating.

In FIG. 1, reference numeral 1 denotes a heating coil;
Reference numeral 3 denotes a control unit comprising an inverter circuit, a switching circuit, and a control circuit, which controls a high-frequency current supplied to the heating coil 1 and controls the entire apparatus. An operation unit provided with means and the like; 4 a cooling fan for cooling the heating elements in the control unit 2; 5 a dust fan provided at the upstream air supply port of the cooling fan 4 An air filter 6 is provided to prevent intrusion of dust and dust, and 6 is an outlet for discharging hot air inside the container to the outside of the container. Reference numeral 7 denotes a metal cabinet (outer shell) containing the heating coil 1, the control unit 2, and the like.
Reference numeral 8 denotes a ceramic plate disposed above the heating coil 1 with a predetermined distance from the heating coil 1. The configuration described above is the same as that of the induction heater used as the cooking device.

The following configuration is added according to the present invention, and 9 is a cushioning material 10 above the ceramic plate 8.
Is a magnetic metal plate for heating (hereinafter referred to as a metal plate) which is disposed via a through hole. Reference numeral 11 denotes a temperature detecting element buried from the lower surface of the metal plate 9 at a position corresponding to the center of the heating coil 1. The temperature detecting element 11 is connected to the control unit 2. Reference numeral 12 denotes a fixing bracket for fixing the metal plate 9 to the cabinet 7, and uses a material having a low thermal conductivity such as a stainless material to reduce heat radiation from the metal plate 9 to the cabinet 7 and is bent. In order to increase the heat resistance by increasing the distance between the metal plate 9 and the cabinet 7 by processing, a convex configuration bent upward with a thin plate material is used. By providing a plurality of bent portions, it is possible to give a rotational movement to the arm portion 12c with the bent portions 12a and 12b as fulcrums.

As shown in FIG. 4, when the metal plate 9 is thermally expanded by heating, the bent portions 12a and 12b have an inner angle from 90 ° to an acute angle and the arm 12c is bent to the left to absorb the elongation of the metal plate. It is. The expansion of the metal due to thermal expansion is very small, and when the temperature of the metal plate falls to room temperature, the dimensions of the metal plate 9 return to the original state, and thus the bent portion 12
The inner angles of a and 12b return to the initial angles (the state of FIG. 3) without causing plastic deformation.

One end of the fixing bracket 12 is fixed to an end of the metal plate 9 by a fastening component (a screw or the like) 17. On the other hand, the other end is fixed to the cabinet 7 by a fastening part 17, but in order to prevent the heat of the metal plate 9 from being dissipated to the cabinet 7 through the fixing bracket 12, the heat insulating between the fixing bracket 12 and the cabinet 7 is provided. Material 18 is attached.

The metal plate 9 is floated on the ceramic plate 8 by the cushioning material 10 to prevent conduction and heat radiation to the body, and by interposing a heat insulating material 18 between the cabinet 7 and the fixture 12. The heat loss is reduced, the heating efficiency is improved, and the temperature of the body including the cabinet 7 is prevented from rising.

Reference numeral 13 denotes an annular metal body as a body to be heated placed at the center of the upper surface of the metal plate 9. The temperature at which the annular metal body 13 is heated when it is mounted on the shaft is an oil seal type bearing. The suitable temperature is 100 to 120 ° C, and 110 to 130 ° C for bearings other than oil seals and around 160 ° C for gears and pulleys. Here, a description will be given of a bearing composed of an inner ring 14, an outer ring 15, and a metal ball 16 mounted between the inner ring 14 and the outer ring 15.

Next, the operation of this embodiment having the above configuration will be described. A bearing, which is an annular metal body 13, is placed at the center of the upper surface of the metal plate 9 and operated by the operation unit 3 (for example, the power switch and the heating on / off switch are turned on, and the temperature control knob is operated to set the temperature. ) And start operation,
A high-frequency current is passed through the heating coil 1 and an induced eddy current flows through the metal plate 9. As shown in FIG. 5, in the initial stage of the heating, the temperature of the portion corresponding to the middle portion between the inner circumference and the outer circumference of the heating coil 1 increases, Since the portion slightly outside the center of the metal plate 9 is annularly heated, an annular high-temperature zone matching the shape of the annular metal body 13 such as a bearing is generated, so that the annular metal body 13 is efficiently produced.
Heat transfer is performed.

The temperature of the metal plate 9 that rises with time while transferring heat to the annular metal body 13 is changed from the lower surface to the metal plate 9.
When the temperature detecting element 11 buried in the sensor detects the temperature and reaches a predetermined temperature which is previously determined to be a set temperature by an experiment, the control unit 2 receives the detection signal and stops the supply of the high-frequency current to the heating coil 1 to stop the metal. The heating of the plate 9 is stopped, and when the temperature detecting element 11 detects that the stopped state is continued and the temperature of the metal plate 9 has decreased by a certain temperature range, the control unit 2 receives the detection signal and sends a signal to the heating coil 1. The supply of the high-frequency current is started again, and the metal plate 9 is heated.

The ON / OFF operation is repeated with a small temperature change width, and the surface temperature of the metal plate 9 is maintained at a predetermined temperature. The ring-shaped metal body 13 is heated to the set temperature without overshooting due to heat conduction and heat radiation from the metal plate 9. The heating of the metal plate 9 is performed intermittently by ON and OFF operations, and heat is transferred to the ring-shaped metal body 13.
Is gradually more uniform than the initial distribution shown in FIG. The temperature distribution of the metal plate 9 becomes more uniform as the plate pressure of the metal plate 9 becomes thicker, and as the heating power becomes smaller and the heating speed becomes lower.

Therefore, according to the present embodiment, since the heating is performed uniformly, not only the general annular metal body 13 but also a temperature-sensitive bearing such as an oil seal type does not leak out of the oil, and the inner ring 14 and the outer ring 15 are not leaked. Metal ball 16 between
The mounting work can be easily performed while maintaining the quality of the bearing without compressing the bearing. In addition, since fine temperature control is performed, even if heating is performed for a long time, overheating is not performed, and overheating is not performed.

In order to minimize the heat radiation from the high-temperature metal plate 9 and to improve the heating efficiency, the metal fittings 12 for fixing the metal plate 9 and the cabinet 7 are made of a material having a low thermal conductivity. In order to increase the heat resistance by increasing the distance between the metal plate 9 and the cabinet 7, a convex structure bent upward with a thin plate material is used. By providing a plurality of bending portions, a structure is provided in which the arm portion 12c is given a rotational movement with the bent portions 12a and 12b as fulcrums.

The metal plate 9 expands thermally when heated. This extends in all directions. Since the end of the metal plate 9 is fixed to the fixing metal 12 and the other end of the fixing metal 12 is fixed to the cabinet 7, the bent parts 12a and 12b of the fixing metal 12 have an inner angle of 90 as shown in FIG. The arm 12c is bent to the left from an angle of acute to absorb the elongation of the metal plate 9. The elongation of the metal due to thermal expansion is very small, and if the temperature of the metal plate 9 decreases to room temperature, the dimensions of the metal plate 9 return to the original state. Therefore, the inner angles of the bent portions 12a and 12b are also the initial angles without causing plastic deformation (the state of FIG. 3).
Return to

One end of the fixture 12 is fixed to an end of the metal plate 9 by a fastening component (such as a screw) 17. On the other hand, the other end is fixed to the cabinet 7 by a fastening part 17, but in order to prevent heat of the metal plate 9 from being radiated to the cabinet 7 through the fixing bracket 12, heat insulation is provided between the fixing bracket 12 and the cabinet 7. Material 18 is attached.

Further, the metal plate 9 is a ceramic plate 8
Above, it is in a floating state by the cushioning material 10 to prevent conduction and heat radiation to the fuselage. Further, by interposing the heat insulating material 18 between the cabinet 7 and the fixture 12, the heat radiation loss is reduced, and the heating efficiency is improved. This is to prevent the temperature of the body including the cabinet 7 from rising.

The annular metal body induction heating apparatus according to the present embodiment is effectively heated and thermally expanded when the steel metal wheel such as a gear or a pulley is mounted as well as a bearing as the annular metal body 13 to be heated. It can be used at a maintenance site or the like where the diameter is increased by a minute predetermined dimension and inserted into the shaft. Further, since oil for heating or the like is not required, there is no problem of odor or troublesome cleaning.

[0029]

According to the present invention, an operation including a heating coil, a control unit for controlling a high-frequency current supplied to the heating coil and controlling the entire apparatus, a power switch, various input operation means, display means, and the like. A metal plate made of a magnetic material is arranged above a ceramic plate placed above a heating coil of an induction heater having a portion and the like via a buffer material, and a lower surface is positioned at a position corresponding to the center of the heating coil of the metal plate. A temperature detecting element connected to the control unit is embedded, and an end of the metal plate is fixed with a fixing metal having an expandable structure, and an annular metal body as a body to be heated is placed on the upper surface of the metal plate. Therefore, not only general ring-shaped metal bodies such as gears and pulley steel wheels, but also temperature-sensitive bearings such as oil seal type can be heated easily and reliably without oil spillage. An annular metal body induction heating device that can perform uniform heating at all times without overshoot, overheating for a long time, without overheating, and without skilled work because of fine temperature control Is provided.

Furthermore, the thermal expansion and shrinkage of the metal plate can be absorbed by the fixing bracket, so that the device can be safely and long-lived without deformation and residual stress of these parts.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a schematic structure of an annular metal body induction heating apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view of the same.

FIG. 3 is a detailed view of the main part, showing a state in which heating is not performed.

FIG. 4 is a detailed view of the main part, showing a state during heating.

FIG. 5 is a temperature distribution diagram of a heated body when the annular metal body induction heating device starts heating.

FIG. 6 is an external perspective view of a ring-shaped metal body heating device according to a conventional example, comprising a hot plate dedicated to bearing heating.

FIG. 7 is an external perspective view of a core type annular metal body induction heating apparatus showing another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating coil 2 Control part 3 Operation part 8 Ceramic plate 9 Metal plate (magnetic metal plate) 11 Temperature detection element 12 Fixture 13 Ring metal body (bearing)

Claims (1)

[Claims] 1. A heating coil (1), a control unit (2) for controlling a high-frequency current supplied to the heating coil (1) and controlling the entire apparatus, etc., and various input operation means and display means. Ceramic plate (8) placed above heating coil (1) of induction heater equipped with operating part (3)
A magnetic metal plate (hereinafter referred to as a metal plate) (9) is disposed above the metal plate (9), and is connected to the control unit (2) from the lower surface at a position corresponding to the center of the heating coil (1) of the metal plate (9). A metal fitting (9) that embeds the temperature detecting element (11) and fixes a metal plate (9) having a low thermal conductivity and a large thermal resistance at the end of the metal plate (9) and having a stretchable structure. 12) is fixed, and an annular metal body (13) as a body to be heated is placed on the upper surface of the metal plate (9). The control unit (2) receives the output of the temperature detecting element (11) and The output to the heating coil (1) is controlled so that the plate (9) reaches the set temperature, and the annular metal body (13) is heated to a predetermined temperature by conduction heat and radiation heat from the metal plate (9). Annular metal body induction heating device.