JPH07102385B2 - Electric heating device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric heating device, and more particularly to an electrode member that is pressed against a member to be heated.

(Prior Art) When heating a steel material for processing, there is an electric heating method in which an electric current is directly applied to the steel material for heating. In this energization heating method, electrode parts are pressed against both ends of the steel material, and the steel material is energized through both of these electrode parts, and the steel material is directly heated by its Joule heat. This energization heating is rapid heating, the high temperature region time is short, and it is also advantageous for scale generation and surface quality. In addition, the electric heating is advantageous in terms of cost because it directly heats the steel material as a resistor and is advantageous in terms of cost. In addition, since the temperature control is on-off control, the responsiveness is also excellent. In addition, electric heating can heat the entire length of the steel material at the same time, eliminating the need for a heat-retaining zone, which is advantageous in terms of equipment and space, and is widely used in place of other induction heating methods, combustion heating methods, etc. Is being done.

(Problems to be Solved by the Invention) However, in the above-mentioned electric heating, in general, since both ends of the steel material are pressed into contact with each other, these electrode portions and both end portions of the steel material where the electrode portions are pressure-contacted are in contact with each other. There is a problem in that the resistance easily causes overheating, and as a result, the temperature of the steel material is locally different and non-uniform.

The present invention has been made in order to solve the above-mentioned problems, and provides an electric heating device for preventing overheating due to contact resistance of an electrode portion and an end portion of a member to be heated which is pressed against the electrode portion. The purpose is to provide.

(Means for Solving the Problems) According to the present invention in order to achieve the above object, according to the present invention, an electric heating for heating by heating the member to be heated by pressing electrode portions on both ends of the member to be heated in the shape of a round bar. In the apparatus, a configuration is provided that is provided near both ends of the heated member, has end surfaces that are in pressure contact with the outer peripheral surfaces near both ends of the heated member, and has a flat surface, and includes electrode portions that make line contact with the heated member. It was done.

(Operation) The electrode portion disposed on the outer periphery near the end of the heated member has its end surface (contact surface) in line contact with the outer peripheral surface near the end of the rod-shaped heated member. By setting the length of this line contact to an appropriate length according to the length of the member to be heated, the value of the current to be applied, etc., the contact resistance is dispersed, and the electrode portion and the member to be heated are The contact resistance is reduced, and the contact portion is prevented from overheating.

(Embodiment) An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a schematic configuration of an electric heating apparatus according to the present invention,
The electric heating apparatus 1 includes a material charging apparatus 2 for mounting a steel material to be rolled, for example, a stainless steel round bar 300 (hereinafter referred to as steel material 300) and charging it into an insertion line mechanism, and a heating apparatus 3 for electrically heating the steel material. , A charging / extracting device 4 which carries in the steel material to be heated from the material charging device 2 to the heating device 3, and takes it out after the heating is finished and carries it out to the conveying device 5, and a rolling device for the heated steel material taken out from the heating device 3. Transfer device to transfer to 5.
The heating device 3 includes a power supply device 6 that supplies necessary electric power and a control device 7 that controls each of these devices at a predetermined timing.

The material charging device 2 includes a mounting table 20 on which the steel material 300 is mounted, a charging mechanism 21, an insertion line mechanism 22 and the like, and the charging mechanism 21 sets the steel material 300 mounted on the mounting table 20 to 1 This is a well-known technique for sequentially supplying each line to the insertion line mechanism 22.

The insertion line mechanism 22 is arranged on one side of the mounting table 20 and temporarily holds the steel material to be supplied to the heating device 3. The insertion line mechanism 22 is composed of a roller conveyor, and a stopper 22a for positioning the material is fixed at one end thereof. , The rollers 22b are individually rotated by motors (not shown), and the steel materials placed on the rollers 22b are transferred in the direction of the stopper 22a along the insertion line LNa, and the tip surface thereof is the stopper 22a.
Position it by locking it to. The insertion line mechanism 22 is provided with a detection device 8 for detecting the length of the steel material, as shown in FIG. 11 described later, along the insertion line mechanism 22.

The detection device 8 is composed of a plurality of, for example, 6 sets of photoelectric detectors 80 to 85 arranged at a predetermined interval from the other end of the insertion line mechanism 22 toward the center, and the light emitting elements of the photoelectric detector 80.
80a and the light receiving element 80b are arranged facing each other on both sides of the insertion line LNa, and detects the presence or absence of the rear end of the steel material placed on each roller 22b of the insertion line mechanism 22, that is, the length of the steel material. . The other photoelectric detectors 81 to 85 are also configured similarly to the photoelectric detector 80. Each of these detectors 80 to 85 is connected to the control device 7.

The heating device 3 is for electrically heating the steel material, is arranged along one side of the insertion line mechanism 22, and has a pair of rails 30 and 30 laid on the floor and the rails 30 and 30. Bus bar 31 for power supply laid parallel to the outside and rail
A fixed carriage 32, which is arranged and fixed on one end side of 30 and has a heating electrode section arranged on the upper side thereof, and a heating carriage section which is movably mounted on the rail 30 so as to be opposed to the fixed carriage 32. It is composed of a moving carriage 33 and the like in which is provided.

The charging / extracting device 4 is composed of a plurality of, for example, five charging / extracting machines 40 to 44 and a holder mechanism 45 (Fig. 11), and each of the charging / extracting machines 40 to 44 has an insertion line mechanism 22 as shown. The rails 30 of the heating device 3, the bus bars 31 and the like are arranged orthogonally to each other at a predetermined interval.

The transport device 5 is arranged on the opposite side of the heating device 3 from the insertion line mechanism 22, and is constituted by a roller conveyor.
5a is driven by a motor (not shown) to convey the steel material placed on each of these rollers 5a in the direction of arrow A of the conveyance line LNb. A rolling device (not shown) is arranged on the extension of the transfer line LNb in the direction of arrow A.

As shown in FIGS. 2 and 3, the power supply bus bar 31 includes a pair of fixed bus bars 31A and 31A and a pair of moving bus bars 31B and 3B.
1B and each of these fixed bus bars 31A, 31
A, the moving busbars 31B, 31B are each formed of a copper rectangular rod-like body, and are electrically connected to a plurality of support rollers 34 arranged on the outer surface of each rail 30, 30 along the longitudinal direction thereof at predetermined intervals. It is insulated and supported by. Each fixed bus bar 31A, 31A
Are fixed, one end 31a, 31a (Fig. 2) is located at the substantially central position of these rails 30, 30, and the other end 31a ', 31a' is higher than the other end of each rail 30, 30 in the power source. It projects to the device 6 side.

The movable bus bars 31B, 31B are parallel to the outer sides of the fixed bus bars 31A, 31A, respectively, with a slight gap, and are arranged on each roller 34 so as to be movable along the longitudinal direction of each of these fixed bus bars 31A, 31A, and the other ends thereof. 31b 'and 31b' are fixed to both sides of the moving carriage 33 as described later and are connected to respective electrode portions mounted on the moving carriage 33, and slide along with the movement of the moving carriage 33 to move the moving carriage 33. The length of the connecting conductor between the power supply device 6 and the power supply device 6 is minimized to reduce the conductor loss. Further, the other ends 31b and 31b of these movable bus bars 31B and 31B are movable trolleys.
In a state in which 33 is retracted to the maximum retracted position indicated by the chain double-dashed line, the fixed bus bars 31A, 31A are located at substantially central positions of the rails 30, 30 and the clamp mechanism 3 is provided with the respective ends 31a, 31a.
Abutment is possible from 5, 35.

Clamping mechanism 35, 35 is one end 31 of fixed bus bar 31A, 31A
The movable bus bars 31B and 31B are provided at the outer positions of a and 31a.
Is pressed from its outer side to press the fixed bus bars 31A, 31A, 31A of the fixed 31A, which are opposed to each other, to electrically connect them, and the hydraulic cylinder 35a and the rod 35b of the hydraulic cylinder 35a. It is composed of a pressing pad 35c attached to the tip. When the hydraulic cylinder 35a is extended, the moving busbar 31B is brought into pressure contact with one end 31a of the fixed bumper bar 31A via the pad 35c, and when shortened, the pressing force is released to bring them into sliding contact with each other so that the moving busbar 31B can move.
Each hydraulic cylinder 35a, 3 of each of these clamp mechanisms 35, 35
A solenoid valve (not shown) that drives 5a is controlled by the controller 7.

The other ends 31a ', 31a' of the fixed bus bars 31A, 31A are connected to the positive electrode terminal 6a (first terminal) of the power supply device 6 via connecting members 31c, 31c, respectively.
Figure) connected. The load terminals 6b, 6b of the power supply device 6 are connected via connecting members 36, 36 to an electrode portion, which will be described later, mounted on the fixed carriage 32.

The fixed carriage 32 is configured as shown in FIGS. 4 and 5,
The base 100 of the fixed carriage 32 is fixed to one end of the rail 30 as described above, and a pair of rails 101 and 101 are laid on the base 100 in parallel with the rail 30. A pedestal 103 is slidably mounted on a pair of guides 102, 102 on the substrate 101. An air cylinder 104 is arranged between the base 100 and the pedestal 103 along the sliding direction of the pedestal 103, the bottom end of the cylinder portion 104a is fixed to the upper rear portion of the base 100, and the rod 104b is fixed. The tip is a pedestal via a connecting member
It is fixed to the bottom front part of 103. The gantry 103 can be advanced in the direction indicated by the arrow B by the maximum stroke L ₁ by the extension of the air cylinder 104. This stroke L ₁ is for retracting the fixed carriage 32 when the steel material is carried in and out of the heating device 3.

Three support members 105 to 107 are provided on the pedestal 103, the support member 105 is provided at the rear end of the pedestal 103, and the support members 106 and 107 are provided separately on both sides of the front end so as to face each other. Support member 10
5 is a hole in the center at a position matching the axial center position LNc of the heating device 3.
105a is provided, an air cylinder 110 is provided on the rear end surface of the supporting member 105, and a rod 105b of the air cylinder 110 is loosely fitted in the hole 105a so as to project forward and the electrode supporting member 115 at the tip. Is installed.

An intermediate position between the two support members 106 and 107 of the gantry 103 and an upper portion of the support members 106 and 107 with the axis LNc as the center thereof.
Holes 103a, 106a, 107a that are opened in the radial direction are formed. And, each of these holes 103a, 106a, 107a is the core LN.
They are arranged at equal intervals in the circumferential direction on a circle centered on c. The hydraulic cylinder 1 is provided at the position of the hole 103a on the bottom surface of the frame 103.
11, a rod 111a is loosely fitted in the hole 103a and protrudes upward, and an electrode support member 116 is attached to the tip. A hydraulic cylinder 112 is also arranged outside the hole 106a of the support member 106, and the rod 112a thereof is loosely fitted in the hole 106a and protrudes inward, and an electrode support member 117 is attached to the tip thereof. Similarly to the support member 106, the support member 107 has a hydraulic cylinder.
113 is attached, and an electrode support member 118 is attached to the tip of the rod of the hydraulic cylinder 113.

Each electrode support member 115-118 is electrically connected and fixed to the support member 105 via flexible conductors 120-123. A connection terminal 125 is electrically connected and fixed to the support member 105,
Both ends of the connection terminal 125 are connected to the connection members 36, 36 shown in FIG. 2 through the flexible conductors 126, 126.

As shown in FIG. 5, an electrode member 130 is attached to the position of the shaft center LNc of the electrode supporting member 115, and the electrode members 131 to 131 are attached to the shaft center positions of the electrode supporting members 116 to 118 as shown in FIG. It is fitted with 133. The electrode member 115 can be moved forward and backward according to the expansion and contraction of the air cylinder 110. When the air cylinder 110 is extended, it is advanced in the direction of arrow B as shown in FIG. Is retracted until it touches. The electrode members 131-133 are hydraulic cylinders 111-113.
According to the expansion and contraction of the shaft, the shaft can be moved in the radial direction of a circle centered on the axis LNc. When the cylinders 111 to 113 are extended, the tip surfaces of the electrode members 131 to 133 are gathered on the axis Lc, and when the cylinders are shortened, the electrode support members 116 to 118 are mounted on the mount 103 and the support member 10.
Retreat until it contacts 6 and 107. Each of these hydraulic cylinders 110 to 113 is controlled by the control device 7.

As shown in FIGS. 5 and 7, the electrode member 130 mounted on the electrode support member 115 has a substantially conical shape, and its tip 130a is formed in a substantially hemispherical shape. Tip 1 of this electrode member 130
30a is brought into contact with the end surface of the steel material 300 as shown in FIG. Further, as shown in FIG. 6, the electrode member 131 mounted on the electrode support member 116 is formed into a substantially columnar body, and its tip is cut out in a substantially wedge shape from both sides at a predetermined angle to form inclined surfaces 131a and 131a.
And the end surface 131b thereof has a predetermined length d in the diametrical direction.
It is formed by forming a slanted surface 131c by cutting out only. The width of the tip surface 131b is w as shown in FIG. 7C, and the end surface 131b can be in line contact with the side surface of the one end 300a of the steel material 300 as shown in FIG. Other electrode member 13
2 and 133 are formed similarly to the electrode member 131. Therefore, regardless of the outer diameter of the steel material 300, the three electrode members 131 to 133 are capable of abutting the respective end surfaces on the end surface of the steel material along the longitudinal direction and at equal intervals in the circumferential direction.

These electrode members 131 to 133 have an end face 131b (only one of which is shown) having an appropriate length, for example, d ₁ , d ₂ (d ₁ > d, d ₂ > d) depending on the steel material to be heated. It can be used by exchanging it with another one. In this way, by changing the contact length d of the electrode members 131 to 133 to the steel material, the contact resistance is dispersed,
It is possible to prevent overheating of the contact portion.

As shown in FIG. 4, a nozzle 135 for cooling is arranged on the upper part of the electrode support member 117, and its nozzle (tip) 135a.
Is one end of the shaft core LNc, that is, the steel
It is arranged so as to face one end 300a (Fig. 7) of 300 and the other end 135b.
Is connected to the cooling system via a hose 136. For example, air is used as the cooling medium, and the hose 136 is connected to an air source (both not shown) via a solenoid valve. This solenoid valve is controlled by the control device 7. Since the end portion 300a of the steel material 300, which is pressed against the electrode members 131 to 133 during electric heating, is locally overheated compared to other portions, the steel material 300 is cooled by blowing air to the end portion 300a. It is installed to keep the temperature of 300 as a whole. Such nozzle 135
The number may be one as shown, or may be provided for each electrode supporting member.

Note that the cooling medium is not limited to the air, and other materials such as water are used to mist the water and the steel material 30 is used.
You may make it cool by spraying on the overheated part of the 0 end part 300a.

The movable carriage 33 is configured as shown in FIGS. 8 and 9,
The base 150 has two sets of rollers 15 mounted on the front and rear of the bottom.
Mounted movably on rails 30, 30 via 1, 152,
Further, the motor 153 housed in the base 150 allows the vehicle to move back and forth. On the base 150, a pair of rails 154, 154 are laid in parallel with the rail 30. These rails 154, 1
A pedestal 156 is slidably mounted on the 54 via two pairs of guides 155, 155 fixed to the front and rear ends of the bottom surface, respectively.

An air cylinder 157 is arranged along the rail 154 at a central position between the base 150 and the pedestal 156, and the bottom end of the cylinder portion of the cylinder 157 is at the rear end of the upper surface of the base 150 and the tip of the rod. Are fixed to the front end of the bottom surface of the frame 156, respectively. Stand 1
When the cylinder 157 is extended, it can be moved to the front end position as shown by the solid line in FIG. 9 and to the rear end position as shown by the two-dot chain line by the maximum stroke L ₂ when it is shortened. The cylinder 156 is set free when energized to allow the movable carriage 33 to move freely, and absorbs a change in length due to thermal expansion of the steel material caused by the energization. Support members 160 to 162 are arranged on the pedestal 156 similarly to the fixed carriage 32, and the electrode support members 170 to 162 are provided on the support members 160 to 162 via air cylinders 165 and hydraulic cylinders 166 and 167, respectively. 172 is mounted, and an electrode support member 173 is arranged on the gantry 156 at an intermediate position between the support members 161 and 162 via a hydraulic cylinder 168.

Electrode members 175 to 178 are mounted on the electrode supporting members 170 to 173, and these electrode members 175 to 178 are formed similarly to the electrode members 130 to 133 (FIG. 4) of the fixed carriage 32. .
Then, the electrode members 130 and 175 of the fixed carriage 32 and the movable carriage 33, respectively.
And are located on the axis LNc and face each other. A nozzle 210 (FIG. 8) is provided above the electrode supporting member 171, and its nozzle has an injection port similar to that of the nozzle 135 shown in FIG.
The shaft LNc is arranged diagonally above 75, and the rear end is connected to the air source via a hose 211 and a solenoid valve (not shown). This solenoid valve is also controlled by the control device 7.

The other ends 31b ', 31b' of the moving bus bars 31B, 31B are respectively the second and third.
As shown in FIGS. 8 and 9, insulating members are fixed to both sides of the base 150 via connecting members 180, 180, and the upper ends of the connecting members 180, 180 have flexible conductors 181, 181, respectively. Connection member
It is electrically connected and fixed to the support member 160 via 182 and 183. Then, the electrode supporting member 1 is provided on the supporting member 160.
70 to 173 are electrically connected and fixed via a flexible conductor.

The two support members 16 provided on both sides of the front end of the pedestal 156.
Supporting members 190, 190 (FIG. 11) are fixedly provided on the reference numerals 1, 162, respectively, with the axis LNc interposed therebetween and projecting forward of the pedestal 156.
Detectors 86, 87 for detecting the rear end position of the steel material 300 are arranged on the respective support members 190, 190 at predetermined intervals along the direction of the axis LNc. These detectors 86 and 87 are the core LN
The presence or absence of the rear end portion of the steel material 300, which is composed of the light emitting elements 86a and 87a and the light receiving elements 86b and 87b which are spaced apart and opposed to both sides of c, and which is disposed at the axis LNc position, is detected. Each of these detectors 86, 87 is connected to the control device 7, respectively.

An extraction mechanism 200 for extracting the heated steel material 300 from the heating device 3 to the transfer device 5 in cooperation with the charging and extracting device 4 is provided on both sides and the front end of the base 150, as shown in FIG. The extraction mechanism 200 is arranged such that each lower end is horizontally bridged to the supporting members 201, 201 fixedly provided on both sides of the front end of the base 150, and each upper end of each of the supporting members 201, 201. Guided
202, an air cylinder 205 horizontally arranged at one end of the guide 202, and a support member fixed to the tip of a rod 205a of the air cylinder 205 and slidably supported by the guide 202 in the horizontal direction. 206, an air cylinder 207 arranged perpendicularly to the support member 206, a clamp mechanism 208 arranged at the tip of a rod 207a of the air cylinder 207, and the like.

The air cylinder 205 includes a support member 206 fixed to the tip of the rod 205a and a shaft core LNc of the heating device 3 indicated by a two-dot chain line 206 '.
From the position of to the position of the transport line LNb indicated by the solid line 2
It can slide horizontally along 02. The clamp mechanism 208 is composed of a pair of arms 208a, 208a which are rotatably supported at their central portions by a supporting member 206a slidably mounted on the supporting member 206 and whose lower ends can be opened and closed. Each arm 208a, the upper end of each 208a is respectively connected to the rod 207a of the air cylinder 207, and when the cylinder 207 is extended, the carrier line LNb and the axis LNc are moved downward and closed,
When shortened, it is moved up and opened. As a result, the end of the steel material 300 heated by the heating device 3 can be sandwiched, extracted from the heating device 3 and placed on the conveying device 5, so that the end portion of the steel material hangs down due to its own weight. To prevent.

An air cylinder 157 that drives a frame 156 of the moving carriage 32, an air cylinder 165 that drives the electrode members 170 to 173, hydraulic cylinders 166 to 168, and air cylinders 205 and 207 of the extraction mechanism 200.
Are each connected to an air source via a solenoid valve, and each of these solenoid valves is connected to the control device 7.

The pedestal 156 is driven, and the air cylinder 157 is provided with solenoid valves 210, 211 and 21 respectively for ports 157b and 157c as shown in FIG.
The solenoid valve 212 is connected to the air source through the solenoid valve 21.
0 or 211 is selectively connected to the air source,
The solenoid valves 210 and 211 have the ports 157b and 157c connected to the solenoid valves 212 and 212, respectively.
Or open to the atmosphere. Each of these solenoid valves 210-2
12 is connected to the control device 7.

As shown in FIG. 11 and FIG. 12, the charging / extracting device 40 of the charging / extracting device 4 (FIG. 1) has its front end orthogonal to the position above each of the rails 30 and 30 and immediately below the unloading line LNb. Movably mounted on a pair of rails 220, 220 that are laid
221, and is arranged between the rail 220 and the carriage 221 and along the moving direction of the carriage 221, the tip of the rod 222a is fixed to one end side of the rail 220, and the cylinder portion 222b.
An air cylinder 222 whose bottom end is fixed to approximately the center of the bottom of the truck 221 and a truck 223 movably mounted on the truck 221.
Between the carriages 221 and 223 and along the moving direction of the carriage 223, and the tip of the rod 224a is mounted on the carriage 22.
An air cylinder 224 fixed to approximately the center of the bottom of 3 and a bottom end of a cylinder portion 224b fixed to one end of a truck 221, and a truck 22
3 and two holder mechanisms 225 and 230 which are arranged at a predetermined interval at the substantially central position.

The air cylinders 222 and 224 respectively advance the carriages 221 and 223 in the direction of arrow D to the position shown by the solid line in FIG. 12 when extended, and retreat in the direction of arrow E to the position shown by the two-dot chain line when shortened. The holder mechanism 225 is composed of an air cylinder 226 arranged vertically to the carriage 223, and a holder 227 fixed to the tip of the rod of the air cylinder 226. When the air cylinder 226 is shortened, the holder 227 is shown in FIG. As indicated by the solid line, the charging line LNa and the axis LNc of the heating device 3 are lowered to a position slightly lower, and when extended, the insertion line LNa and the axis LNc are slightly higher than the positions indicated by the two-dot chain line. Raise to position. The holder mechanism 230 is also configured similarly to 225.

Air cylinders 222, 224 for driving the carriages 221, 223 and air cylinders 226, 231 of the holder mechanisms 225, 230.
The solenoid valve (not shown) for driving the motor is controlled by the control device 7 (shown by a chain double-dashed line in FIG. 11). Other charging and extracting machines 4
1, 42 have the same structure as the charging and extracting machine 40.

As shown in FIGS. 11 and 13, the charging / extracting device 43 of the charging / extracting device 4 (FIG. 1) is laid at the front end above each rail 30, 30 and at a position right below the unloading line LNb at a right angle. Base 240
A dolly 241 movably mounted on the base and these bases 240
And the carriage 241 and along the moving direction of the carriage 241, the tip of the rod 242a is fixed to one end of the base 240, and the bottom end of the cylinder portion 242b is located substantially in the center of the bottom of the carriage 241. A fixed air cylinder 242 and two holder mechanisms 245, 2 arranged at a predetermined distance from the tip of the carriage 241 at a substantially central position.
It is composed of 50 and.

The air cylinder 242 advances the carriage 241 in the direction of arrow D to the position indicated by the chain double-dashed line in FIG. 13 when extended, and retracts it in the direction of arrow E to the position indicated by the solid line when shortened. Holder mechanism
245 is an air cylinder 246 arranged vertically on the carriage 241;
It is composed of a holder 247 fixed to the tip of the rod of the air cylinder 246. When the air cylinder 246 is shortened, the holder 247 is positioned slightly lower than the axis LNc of the heating device 3 as shown by the solid line in FIG. And when it is extended, it is raised to a position slightly higher than the axial core LNc position as shown by the chain double-dashed line. The holder mechanism 250 is also configured similarly to 245.

The air cylinder 242 that drives the carriage 241 and the solenoid valve (not shown) that drives the air cylinders 246 and 251 of the holder mechanisms 245 and 250 are the control device 7 (shown by a chain double-dashed line in FIG. 11). Controlled by. The other charging / extracting machine 44 has the same structure as the charging / extracting machine 43.

The charging / extracting device 4 is further provided with a holder mechanism 45 as shown in FIGS. 11 and 14, and the holder mechanism 45 is located at the center position of the rails 30, 30 of the heating device 3 along the longitudinal direction of the rail 30. A plurality of, for example, 6 are arranged at predetermined intervals. The holder mechanism 45 includes an air cylinder 260 vertically disposed between the rails 30, a table 261 fixed to the tip of the rod of the air cylinder 260, and an axis LNc of the heating device 3 on the table 261. The roller 262 is rotatably supported along the direction. When the air cylinder 260 is extended, the upper surface of the roller 262 is aligned with the axis LNc as shown by the solid line in FIG. 14, and when the air cylinder 260 is shortened, the roller 262 is rotated as shown in the second holder mechanism 45 from the left in FIG. Lower the height H from the core LNc.
The drive of the air cylinder 260 is controlled by the controller 7. Each of the other holder mechanisms 45 has the same structure.

Further, as shown by the chain double-dashed line in FIG. 11, a temperature sensor 88 is arranged near the fixed carriage 32. The temperature sensor 88 has its detection portion as shown in the drawing, which is the axis LNc of the heating device 3.
Tip 300a of steel 300 that is placed facing one end of and heated
The temperature is detected and the corresponding temperature signal is output to the controller 7. The temperature sensor 88 is, for example, an infrared temperature sensor.

The power supply device 6 is each electrode member of the movable carriage 33 of the heating device 3.
175 to 178 for supplying a predetermined DC current, equipped with a high voltage power supply panel, a transformer, a rectifier, a cooling device for cooling the rectifier and a control panel (neither is shown), and inputs a three-phase AC Then, this is rectified and a direct current is output. Incidentally, the output is about 2000 Kw.

When a DC power supply is used as the power supply for the electric heating device, there is no dielectric obstacle during energization compared to the case where a single-phase AC is used. Since the three-phase AC can be used as the power source, the power factor is well balanced, and the power factor can be set to about 100%, so that the power can be effectively used.
For this reason, it is possible to reduce the facility cost of the entire electric heating device in combination with the reduction of the electric power charge and the need for the countermeasure for the induction failure to the peripheral device.

The control device 7 is, as will be described later, the entire electric heating device 1, that is,
The material charging device 2, the heating device 3, the charging and extracting device 4, the conveying device 5, the power supply device 6 and the like are controlled at a predetermined timing,
Carrying in the steel material to be heated from the mounting table 20 to the heating device 3, energization heating, extraction of the steel material that has been heated from the heating device 3 after heating, carrying in the extracted steel material to the transportation device 5 and the transportation device 5 A series of operations such as transporting the steel material carried in to the rolling mill is controlled.

The operation will be described below.

The electric heating apparatus 1 shown in FIG. 1 is capable of electrically heating a steel material having a maximum length from the length La of the mounting table 20 to the minimum length Lb.

In FIG. 1, first, when an operator turns on a start switch (not shown) of the control device 7, the electric heating device 1 starts to operate, and the charging mechanism 21 of the material charging device 2 is set on the mounting table 20.
The steel materials 300 placed on the top are sequentially moved one by one in parallel in the direction of arrow F, and placed on each roll 22b of the insertion line mechanism 22 and loaded. When the steel material 300 is carried in, the insertion line mechanism 22 rotates each roller 22b to move the steel material 300 to the right in the figure and bring the end face of the tip 300a into contact with the stopper 22a (first
1) (shown by the chain double-dashed line in Fig. 1).

The detectors 80 to 85 of the detector 8 (FIG. 11) detect the position of the rear end 300b of the steel material 300 on the insertion line mechanism 22. In this case, the light emitted from the light emitting element 80a of the detector 80 is received by the light receiving element 80b, and as a result, the detection 81 does not detect the rear end 300b. On the other hand, the light emitted from each light emitting element of the detectors 81 to 85 is blocked by the rear end 300b, and therefore these detectors 81 to 85 detect the rear end 300b. The control device 7 determines that the rear end 300b of the steel material 300 is between the detectors 80 and 81 based on the signals from the detectors 80 to 85. In this way, the control device 7 determines the length of the steel material 300.

The charging / extracting device 4 depends on the length of the steel material 300.
You can decide whether to use 1 or not. That is, when the length of the steel material 300 is longer than the position of the detector 81, all the charging and extracting machines 40
~ 44 and the trailing end 300b is between the detectors 82 and 83, the charge extractors 41-44 are used and the trailing end 300b is the detector 84.
, 85 are used, and when the trailing end 300b is not detected by the detector 85, only the charge / extractors 43 and 44 are used.

In the above case where the rear end 300b of the steel material 300 is between the detectors 80 and 81, the controller 7 extends the cylinders 222, 224 of the charging / extracting machine 40 as shown by the solid lines in FIGS. 11 and 12. Let each trolley
221 and 223 are advanced in the direction indicated by arrow D. On the other hand, the trolley
The cylinders 226 and 231 of the holder mechanisms 225 and 230 of 223 are shortened, and the holders 227 and 232 of the holder mechanism 225 and 230 are respectively inserted into the insertion line LN.
a, located just below the axis LNc of the heating device 3. The other charging / extracting machines 41 to 44 are similarly controlled. Also, the shaft core LNc
Each holder mechanism 45 (FIGS. 11 and 14) located immediately below the cylinder has its cylinder extended so that each roller 262 is aligned at the position of the axis LNc.

The fixed carriage 32 (Fig. 5) has the cylinder 104 shortened and the pedestal 1
03 is moved by the stroke L ₁ thereof in the direction indicated by the arrow B ′ and is retracted from the position of the tip 300a of the steel material 300. At the same time, each cylinder 110 of each electrode support member 115-118 (Fig. 4)
~ 113 is shortened, the electrode member 130 is retracted, the electrode member 13
1-133 are retracted from the axial center LNc to the outside in the radial direction. Further, the clamp mechanisms 35, 35 for clamping the movable bus bars 31B, 31B (Figs. 1 and 2) have the cylinders 35a, 35a shortened, respectively, so that the movable bus bars 31B, 31B can be moved.

The moving carriage 33 (FIGS. 1, 8, and 9) is driven by the motor 153 and is retracted in the direction indicated by arrow C ′ to the position indicated by the solid line in FIG. At this time, the moving bus bars 31B, 31B
Moves along with the movable carriage 33 by sliding on fixed bus bars 31A, 31A. Further, the pedestal 156 is retracted by the stroke L ₂ thereof due to the shortening of the cylinder 157 and stopped at the position P1 shown by the two-dot chain line in FIGS. 3 and 9. The solenoid valves 212 and 211 (FIG. 10) that control the cylinder 157 are switched to the port 157c side to shorten the cylinder 157. At the same time, the cylinders 165 to 168 of the electrode supporting members 170 to 173 are shortened so that the electrode members are
175 is retracted, and the electrode members 176 to 178 are retracted radially outward from the shaft core LNc.

The cylinder 205 of the extraction mechanism 200 (FIG. 8) is shortened to move the support member 206 to a position just above the axis LNc as shown by the chain double-dashed line. Further, the cylinder 207 is shortened so that the shaft core LNc
Clamping mechanism 2 just above (at the position of the chain double-dashed line 206 ′)
Open the tip of each arm 208a, 208a of 08.

Next, the control device 7 extends the cylinders 226 and 246 of the holder mechanisms 225 and 245 (only the charging and extracting machines 40 and 43 are shown in FIGS. 12 and 13) of the charging and extracting machines 40 to 44 to extend the cylinders 226 and 246, respectively. Holder 227, 247
The steel material 300 on the insertion line mechanism 22 is placed on top and lifted to a position slightly higher than the insertion line LNa. The same applies to the other charging and extracting machines 41, 42 and 44. Since the charging / extracting machines 41 to 42 and 44 operate in the same manner as the charging / extracting machines 40 and 43, the operation of the charging / extracting apparatus 4 will be described with respect to the charging / extracting machines 40 and 43 for convenience of description below.

The control unit 7 has the charging and extracting machines 40, 43 shown in FIGS. 12 and 13.
The cylinders 224 and 242 are shortened to move the carriages 223 and 241 backward in the direction indicated by arrow E. In this retracted position, the holders 227 and 247 are located directly above the axis LNc of the heating device 3, and the holders 232 and 252 are located directly above the carry-out line LNb. The control unit 7 has the cylinders 226, 246 in this position.
And the steel material 300 on each holder 227, 247 is placed on each roller 262 (FIG. 14) of each holder mechanism 45. In this way, the charging / extracting device 4 carries in the steel material 300 from the insertion line mechanism 22 to the position of the axis LNc of the heating device 3.

After this loading, the charging / extracting machines 40 and 43 are connected to the respective cylinders 226 and 246.
Is shortened to make the holders 227, 247 slightly lower than the shaft core LNc, and is advanced again in the direction of the arrow D to move the holders 227, 2
It is controlled so that 47 is positioned directly below the insertion line LNa and each holder 232, 252 is positioned directly below the axial center LNc.

Next, the control unit 7 controls the cylinder of the fixed carriage 32 (Fig. 5).
104 is extended and the gantry 103 is advanced in the direction indicated by the arrow B, and the tip of the electrode member 130 is brought into contact with the end surface of the tip 300a of the steel material 300. At the same time, the control unit 7 controls the moving carriage 33 (Fig. 9).
The motor 153 is driven to move the movable carriage 33 forward at high speed in the direction indicated by arrow C. The movable carriage 33 moves forward and the light emitting elements of the detector 86 arranged on the supporting members 161, 162 (Fig. 8).
The light emitted from 86a to the light receiving element 86b is the rear end 300 of the steel material 300.
When it is cut off by b, the control device 7 detects the rear end 300b, switches the motor 153 from high speed to low speed, and causes the moving carriage 33 to travel at low speed. Next, the light emitting element 87 of the detector 87
When the light emitted from a to the light receiving element 87b is blocked by the rear end 300b, the control device 7 stops the motor 153 and stops the moving carriage 33 at the position.

After stopping the movable carriage 33, the control device 7 extends the cylinder 157 for a certain period of time to move the pedestal 156 forward so that the tip of the electrode member 175 is brought into contact with the end surface of the rear end 300b of the steel material 300. The cylinder 157 stops at the position where the electrode member 175 comes into contact with the rear end surface of the steel material, and the cylinder 157 is not always extended for the entire stroke. As shown in FIG. 10, the control device 7 controls the solenoid valves 212 and 210 to switch to the port 157b to extend the cylinder 157 as described above, and then connects the solenoid valves 210 and 211 to the atmosphere to connect them to the cylinder. The ports 157b and 157c of 157 are made to communicate with the atmosphere, respectively, so that they can freely expand and contract.

After stopping the positioning of the movable carriage 33, the control device 7 extends the cylinders 35a, 35a of the clamp mechanisms 35, 35 for fixing the movable busbars 31B, 31B (Figs. 1, 2, 3), and the pads 35
These moving bus bars 31B and 31B are pressed and fixed to the fixed bus bars 31A and 31A by c and 35c, and both are electrically connected. This makes it possible to always adjust the length of the moving bus bars 31B, 31B according to the position of the moving carriage 33, that is, the length of the steel material 300, so that the length of the power feeding conductor can always be set to the minimum length.

After the positioning of the fixed carriage 32 and the movable carriage 33 as described above, the control device 7 controls the cylinders 110 of the electrode support members 115 (Fig. 5) and 170 (Fig. 8) of the carriages 32 and 33, respectively. 165
(Fig. 9) is extended to attach each electrode member 130, 175 to the steel material 300.
The front and rear end surfaces are pressed into contact with each other to securely connect them. At the same time, the cylinders 111 to 113 (FIG. 4) of the electrode support members 116 to 118 and the cylinders 166 to 168 (FIG. 8) of the electrode members 171 to 173 are extended to form the electrode members 131 to 13.
3, 176 to 178 are respectively moved in the center, that is, in the direction of the axis LNc, and are pressed into contact with the peripheral surfaces of the front end 300a and the rear end 300b of the steel material 300 at three locations to electrically connect and hold the steel material 300. .

FIG. 7 shows a state in which the electrode members 130 and 131 are pressed against the steel material 300. The electrode member 130 has its spherical tip end 130a pressed against the end surface of the steel material 300 and is in point contact. Electrode member 17 of mobile carriage 33
Similarly to the electrode 130, the spherical tip of the electrode 5 is pressed against the end surface of the steel material 300. The end surface 131b of the electrode member 131 is made of steel 3
The tip end 300a of 00 is pressed and line-contacted from its end face position along its axial direction along its length d (FIG. 6 (b)). The contact length of the end surface 131b of the electrode member 131 with the steel material 300 is changed to an appropriate length according to the diameter and material of the steel material 300.

The other electrode members 132, 133, 176 to 178 are similarly made of the steel material.
The front end 300a and the rear end 300b of the 300 are pressed against each other at three locations. By using such an electrode member, it is possible to disperse the contact resistance and prevent overheating. Also, each electrode member 131-133 and 17
6 to 178 are pressed onto the peripheral surfaces of the front and rear ends of the steel material 300 from their respective end face positions to thereby press the front end 300a and the rear end 300b.
Can supply a sufficient current.

After the mounting of the steel material 300 on the heating device 3 is completed as described above, the control device 7 operates the power supply device 6 (Fig. 1) to output a predetermined DC current from the positive electrode terminal 6a, and the fixed bus bar. 31A, 31A → movable busbars 31B, 31B → electrode members 175 to 178 of movable carriage 33 (Fig. 8) → steel material 300 → fixed carriage 32
Each of the electrode members 130 to 133 (Fig. 4) → connecting terminals 36, 36 → a large direct current is passed through the path of the negative electrode terminal 6b to electrically heat the steel material 300. During this electric heating, the electrode support members 117 (Fig. 4) and 171 (Fig. 8) of the fixed carriage 32 and the movable carriage 33 are shown.
Air is blown from the nozzles 135 and 210 disposed on each of the steel materials 300 including the respective electrode members to the front end 300a and the rear end 300b of the steel material 300 to cool them, and the respective electrode members and the front end 300a, the rear end are cooled.
Prevents abnormal overheating of 300b. As a result, the entire steel material 300 is heated to a uniform temperature.

As the steel material 300 is heated, its length is expanded by thermal expansion, and when the length is expanded, the electrode members 130 and 175 of the fixed carriage 32 and the movable carriage 33 are pressed in the axial direction. Fixed trolley 32
The pedestal 103 is fixed by a cylinder 1104 so that it cannot be retracted, and each electrode member 130 is pressed against the tip 300a of the steel material 300.
˜133 are fixed to the supporting members 105 to 107 and are immovable. On the other hand, the cylinder 157 of the pedestal 156 of the moving carriage 33 is expandable and contractable because the ports 157b and 157c are connected to the atmosphere as described above. In addition, the movable carriage 33
Each of the electrode members 175 to 178 also fixes the rear end 300b of the steel material 300 immovably. As a result, the cylinder 157 of the moving carriage 33 is shortened by the axial pressing force of the steel material 300 at the time of the extension, and the pedestal 156 retracts according to the extension. That is,
The electrode members 175 to 178 are retracted while holding the rear end 300b of the steel material 300 and absorb the change in length due to thermal expansion.

The temperature sensor 88 (Fig. 11) detects the temperature near the tip 300a of the steel material 300 and outputs a corresponding temperature signal. Control device 7
Determines whether or not the temperature of the steel material 300 has reached a predetermined heating temperature based on the temperature signal from the temperature sensor 88, and when the predetermined temperature is reached, the operation of the power supply device 6 is stopped and the steel material 300 is energized. To stop.

After the heating of the steel material 300 is completed, the control device 7 shortens the cylinders 110 to 113 and 165 to 168 of the fixed carriage 32 and the movable carriage 33 to separate the electrode members 130 to 133 and 175 to 178 from the steel material 300. The pedestals 103 and 156 can be moved backward to extract the steel material 300 that has been heated. At the same time, the control unit 7 controls the cylinders 226, 231 and 24 of the holder mechanisms 225, 230 and 245, 250 of the charging and extracting machines 40 (Fig. 12) and 43 (Fig. 13), respectively.
6 and 251 are extended to each holder 22 of holder mechanism 225 and 245.
The steel materials 300, which are carried into the insertion line mechanism 22 by 7 and 247 and are to be heated next, are supported, and the heated steel materials 300 are supported by the holders 232 and 252.

Further, the control device 7 is an extraction mechanism 200 for the movable carriage 33 (FIG. 8).
Cylinder 207 is extended to lower support member 206a,
The rear end 30 of the heated steel material 300 by the clamp mechanism 208
Hold 0b. This prevents the rear end 300b of the heated steel material 300 from hanging down by its own weight.

Next, the cylinders 224 and 242 of the insertion extractors 40 and 43 are shortened to retract the carriages 223 and 241 in the arrow E direction, and the holder 22
7 and 247 are placed right above the axis LNc of the heating device 3, and the holder 23
2, 252 is moved to a position directly above the transfer line LNb of the transfer device 5 (FIG. 1), and the cylinder 205 of the extraction mechanism 200 is extended to move the support member 206 directly above the transfer line LNb. Further, each roller 5a of the transport device 5 (FIG. 1) is rotated in the direction of arrow A so that it can be transported.

Next, the control unit 7 controls the cylinders 226, 231 and the holders 225, 230 and 245 and 250 of the charging and extracting machines 40 and 43, respectively.
246, 251 are shortened, the steel material 300 supported on the holders 227, 247 is placed on each roller 262 of each holder mechanism 45, and the heated steel material is supported on the holders 232, 252. The 300 is placed on each roller 5a of the conveying device 5 (FIG. 1), and the cylinder 207 of the support member 206 of the extraction mechanism 200 is shortened to open the clamp mechanism 208 and the rear end 30 of the steel material 300 concerned.
Release 0b. The conveying device 5 moves the heated steel material 300 loaded and placed on each roller 5a toward a rolling device (not shown) arranged on the extension of the conveying line LNb at a high speed in a direction indicated by an arrow A. Transport.

The charging / extracting machines 40 and 43 (Figs. 12 and 13) are again trolley 22
3, 241 is advanced in the direction of arrow D to move the holder mechanisms 225, 245
Is placed directly below the insertion line LNa of the insertion line mechanism 22, and the holder mechanisms 230 and 250 are placed immediately below the axis LNc of the heating device 3 and stands by. On the other hand, fixed carriage 32 and movable carriage 33
Each of the pedestals 103 and 156, each of the electrode members 130 to 133 and 175 to 178
Is also driven as described above, and is pressed against the front end 300a and the rear end 300b of the steel material 300 to be heated next.

Such operations are repeated to sequentially heat the steel material 300 placed on the mounting table 20 and convey it to the rolling device.

In addition, the steel material 300 mounted on the mounting table 20 of the material charging device 2
If the length is Lb as shown in FIG. 1, as described above, the charging / extracting machines 40 to 42 are fully retracted to the position shown by the chain double-dashed line in the direction of arrow E in FIG. Position of mobile trolley 33
Allows forward movement up to P3 (Fig. 3). Of course, at this time, the three holders 45 shown in FIG. 11 from the middle left to the third from the left do not operate. Therefore, the two charging / extracting machines 43 and 44 and the two holder mechanisms 45 are driven to drive the heating device 3 for the steel material 300.
Carry in and out. Of course, the length L of the steel material 300 is Lb
When <L <La, the charging / extracting machine 40-
A suitable number of loading and extracting machines and holder mechanisms 45 out of 42 are used.

(Effects of the Invention) As described above, according to the present invention, in the electric heating device that presses the electrode portions to both ends of the round bar-shaped member to be heated to energize and heat the member to be heated, the member to be heated is Is disposed near both ends of the member to be heated, the end faces of the member to be heated that come into pressure contact with the outer peripheral surface near the ends are formed into a flat surface, and the electrode member is provided in line contact with the member to be heated. It is possible to reduce the contact resistance with the heating member, and accordingly it is possible to prevent local overheating of the heated member, and it is possible to heat the heated member to a substantially uniform temperature. At the same time, there is an excellent effect that overheating of the electrode portion is prevented.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an electric heating apparatus according to the present invention, FIG. 2 is a plan view of a power supply bus bar of FIG. 1,
3 is a side view of FIG. 2, FIG. 4 is a front view of a fixed carriage,
FIG. 5 is a side view of the fixed carriage of FIG. 4, FIG. 6 is a view showing an embodiment of the electrode member, FIG. 7 is an enlarged view of the essential parts showing the relationship between the electrode member and steel material, and FIG. FIG. 9 is a side view of the moving carriage shown in FIG. 8, FIG. 10 is a circuit diagram of a cylinder for driving the mount of the moving carriage shown in FIG. 9, and FIG. 11 is a main part of FIG. FIG. 12 is a side view of the charging and extracting machine of FIG. 11, and FIG. 14 is a side view of FIG. 2 ... Material charging device, 3 ... Heating device, 4 ... Charge extraction device, 5 ... Conveying device, 6 ... Power supply device, 7 ... Control device, 8 ... Detection device, 22 ... Insertion Line mechanism, 30 …… Rail, 31 …… Power supply busbar, 31A …… Fixed busbar, 3
1B: Moving bus bar, 32: Fixed trolley, 33: Moving trolley, 35: Clamping mechanism, 40-44: Charging / extracting machine, 45 ...
… Holder mechanism, 300 …… Steel material.

Claims (1)

[Claims] 1. A current-carrying heating device for heating an electric current by heating the member to be heated by pressurizing electrode portions to both ends of the member to be heated in the shape of a round bar. An electric heating apparatus, comprising: an end portion which is in flat contact with the outer peripheral surfaces near both ends of the member to be heated, and which is provided with an electrode portion which is in line contact with the member to be heated.