JPH07242933A - Semi-opening induction hardening coil - Google Patents

Abstract

PURPOSE:To provide the subject coil able to the used safely without heating a coil holding member and having extended service life of the coil. CONSTITUTION:This device is provided with a hollow shaped first heating coil 21 having an arc part, a second heating coil 22 having almost the same shape as the first heating coil 21 and arranged opposite the first heating coil 21 at a prescribed interval D, electric power supply coils 23, 24 whose are ends are connected to almost center parts of the first and the second heating coils, respectively, connecting coils 25, 26 connecting both ends of the first and the second heating coils 21, 22 to each other, cooling liquid supplying pipes 61A, 61B respectively connected to the other ends of the electric power supply coils 23, 24, cooling liquid discharging pipes 62, 63 respectively connected to the first and the second heating coils 21, 22 and a core 60 arranged in each coil. The first and the second heating coils 21, 22 are arranged at an interval smaller than the interval D near the center parts of the arc parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semi-open induction hardening coil, and more particularly to a semi-open induction hardening coil for hardening an annular hardening surface of a hardened object such as a crankshaft pin or a journal.

[0002]

2. Description of the Related Art A conventional technique will be described below with reference to the drawings, taking as an example the case of quenching a pin of a crankshaft. FIG. 4 is an external perspective view of a conventional semi-open induction hardening coil, FIG. 5 is a cross-sectional view taken along the line BB of FIG. 4, and FIG. 6 is a high frequency wave for explaining a state in which the induction hardening coil is placed on the hardened portion. It is a principal part front view of a hardening apparatus.

A conventional half open induction hardening coil (hereinafter referred to as quenching coil) 50 is a heating coil 5 as shown in FIG.
1, 52, 53, 54 connecting coils 55, 56, 57, feeding coils 58, 59 and a core 60. Each of these coils is made of a hollow, highly conductive metal.

The heating coils 51, 52, 53, 54 have substantially the same shape, and are formed in a substantially 1/4 arc shape so as to correspond to the shape of the surface 11 of the pin 10. Heating coil 51
Has a front end at one end of the feeding coil 58 and a rear end at the connection coil 5
5 and the front end of the heating coil 52 are connected to the rear end of the connection coil 55, respectively. The rear end of the heating coil 52 and the front end of the heating coil 53 are connected to the connection coil 56. The heating coils 53 and 54 are connected to the connection coil 57 and the power feeding coil 59 according to the above. The quenching coil 50 is formed in an S shape in plan view.
The power supply 4 is connected to the power supply coils 58 and 59 via the lead body 41.
0, the hollow portion of the coil is a cooling liquid supply pipe 6
1, the discharge pipe 62 is connected.

As shown in FIG. 5, the heating coils 51, 52, 53, 54 and the connecting coils 55, 56 are covered with a core 60 made of laminated steel plates or ferrite, except the surface 60A. This core 60 has heating coils 51, 5
This is for focusing the magnetic flux generated by the currents flowing through 2, 53, 54 and the connecting coils 55, 56 in the core 60 and concentrating the magnetic flux emitted from the core 60 on the surface 11 of the pin.

The quenching coil 50 is mounted on an induction hardening apparatus as shown in FIG. In the figure, 64 is a coil side plate, 6
Reference numeral 8 is a jacket for spraying the quenching cooling liquid onto the surface 11 of the pin 10.

Further, in order to prevent the quenching coil 50 from coming into contact with the pin 10 during quenching of the pin 10 and to keep the gap distance between the quenching coil 50 and the pin 10 constant, the quenching coil 5
A spacer 65 is provided in the central portion of 0 and side spacers 66 are provided on both sides of the quenching coil 50. Both the spacers 65 and 66 are attached to the coil side plate 6 by bolts 67.
It is fixed at 4.

The coil side plate 64 is responsible for load fluctuations of the quenching coil 50 and a transformer (not shown) for supplying electric power to the quenching coil 50 due to crank motion.
It is composed of aluminum plate, brass plate, glass laminate plate, etc. Further, each of the spacers, particularly the spacer 65 at the central portion is made of a cemented carbide chip material.

After the quenching coil 50 is arranged so as to closely face and face the surface 11 of the pin 10, the crankshaft is rotated. The cooling liquid for the quenching coil 50 is supplied to the supply pipe 61, passes through the hollow portion of the quenching coil 50 to cool the coil, and then is discharged from the discharge pipe 62.

The high frequency current is supplied from the power source 40 to the power feeding coil 58.
The heating coil 51, the connecting coil 55, the heating coil 52, the connecting coil 56, the heating coil 53, the connecting coil 57, the heating coil 54, and the power feeding coil 59 flow through the surface 1 of the pin 10.
1 is heated by the induced current by the coils.
The cooling liquid is supplied from the power supply pipe 61, cools each coil, and is discharged from the discharge pipe 62.

[0011]

However, in the quenching coil 50, the spacer 65 located in the central portion of the quenching coil 50 by the induction current due to the high frequency current flowing through the connecting coil 56 in the central portion forming the S-shape. Is heated and finally reaches a red hot state. Therefore, the coil side plate 63 also has a high temperature.

Since the side spacer 66 is not surrounded by the quenching coil 50, it does not heat like the spacer 65, but in any case, it is dangerous for the coil holding member of the induction hardening device to glow red. However, improvement was requested for safety measures.

The present invention was devised in view of the above circumstances, and an object thereof is to provide a quenching coil which is safe and has a long life without the coil holding member being heated.

[0014]

A semi-open induction hardening coil according to the present invention is disposed substantially above a to-be-quenched surface above an annular hardened surface of a to-be-quenched object. Or a hollow first heating coil having an arc portion formed by a circle smaller than a semicircle, and having a substantially same shape as the first heating coil, and having a predetermined distance from the first heating coil. A second heating coil that is disposed so as to face each other and is close to the surface to be quenched, and a pair of hollow shapes whose one ends are connected to substantially central portions of arc portions of the first and second heating coils. Power feeding coil, a pair of hollow connecting coils connecting both ends of the first and second heating coils, a cooling liquid supply pipe connected to the other end hollow portion of the power feeding coil, and A coolant discharge pipe connected to a second heating coil, and the quenching of the first and second heating coils and the connecting coil. And a core formed so as to cover a surface that does not face, and the vicinity of the central portion of the arc portion of the first and second heating coils is arranged narrower than the predetermined distance interval, A high frequency voltage is applied between the other ends of the power feeding coils.

Further, the cooling liquid discharge pipe is provided at opposite ends of the heating coil, and the hollow portions of the first and second heating coils and the connecting coil are arranged according to the length of the cooling liquid passage. The cooling liquid is made to flow evenly in each of the coils by forming grooves having different widths.

[0016]

Function: The high frequency current is divided into two parts by the power supply coil and supplied to the left and right. . One of the two is divided into a feeding coil, a left half of the first heating coil, a connecting coil, a route passing through the left half of the second heating coil, and the other is a feeding coil.
The first half of the heating coil is divided into the right half and the connection coil is divided into the route of the right half of the second heating coil. High-frequency currents flow in opposite directions at the center of the arc, so
The induced current is canceled by the spacer placed in this portion.

The cooling liquid for the quenching coil is divided into two and supplied from the supply pipe. One of the two divided parts is from the discharge pipe after cooling the coil through the left half of the power feeding coil first heating coil, and the other is from the discharge pipe through the power feeding coil, the right half of the first heating coil and the connecting coil. Is discharged.
One of the two halves is discharged to the discharge pipe via the power supply coil, the left half of the second heating coil and the connecting coil, and the other is discharged from the discharge pipe via the power supply coil and the left half of the second heating coil. It

Since the groove width of the cooling liquid flowing from the supply pipe is changed based on the length of the passage, the cooling liquid flows evenly in each coil and is discharged from the discharge pipe. Therefore, the first and second heating coils are cooled uniformly.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings.
A half-open induction hardening coil for hardening the surface of the crankshaft pin will be described as an example.

FIG. 1 is a schematic external perspective view for explaining an embodiment of the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG.
FIG. 3 is an explanatory diagram of an electric current and a coolant flow path. The same components as those described in the related art will be described with the same reference numerals.
A semi-open induction hardening coil (hereinafter referred to as a hardening coil) 20 of the present embodiment is arranged close to the surface 11 of the pin 10 of the crankshaft and is used for hardening the surface 11.

As shown in FIGS. 1 and 3, the quenching coil 20 comprises a first heating coil 21, a second heating coil 22, feeding coils 23 and 24, connecting coils 25 and 26, and a core 60. ing. Each of these coils is made of a hollow, highly conductive metal.

The first heating coil 21 has an arc portion 21a formed in a substantially semicircular shape or a circle smaller than the semicircle so as to correspond to the shape of the surface 11 of the pin. However, the value is not limited to the semicircle, and an appropriate value is selected depending on the required depth of the hardened layer and the like.

The second heating coil 22 has substantially the same shape as that of the first heating coil 21, and faces the first heating coil 21 with a predetermined distance D to the surface 1 of the pin.
1 is arranged.

The first heating coil 21 and the second heating coil 22 are bent and formed so that a predetermined distance interval is narrower than the distance interval D in the vicinity of the substantially central portion of the arcuate portions 21a, 22a. One ends of the power feeding coils 23 and 24 are electrically connected to the portion.

A pair of connecting coils 25 and 26 are electrically connected to both ends of the first and second heating coils 21 and 22. The other ends of the power feeding coils 23 and 24 are electrically connected to the high frequency power source 40 via a lead body 41 (see FIG. 6), and the hollow portions of the power feeding coils 23 and 24 are cooling liquid supply pipes 61A and 61B, respectively. It is connected to the. Coolant discharge pipes 62 and 63 are connected to the target positions of the ends of the first and second heating coils 21 and 22, respectively.

As shown in FIG. 2, the first and second heating coils 21 and 22 and the connecting coils 25 and 26 are made of a laminated steel plate or a ferrite system as shown in the example of the first heating coil 21. Is covered with a core 601 having a substantially U-shaped cross section except for a surface 60A facing the surface 11. Reference numeral 30 in the figure denotes a groove formed on the inner surface in the longitudinal direction of the coil. (The groove 30 will be described later.)

Further, in order to keep the quenching coil 20 and the pin 10 at a predetermined distance, a spacer 65 is attached near the feeding coils 23 and 24 by a method similar to that shown in FIG. A side spacer 66 is attached near the connection coils 25 and 26. Furthermore, quenching coil 20
According to FIG. 6, a jacket 68 (not shown) for injecting a cooling liquid for quenching is provided on the surface 11 of the pin 10 heated by.

Next, the operation of this embodiment will be described. The quenching coil 20 is arranged such that the first and second heating coils 21 and 22 approach the surface 11 of the pin and face the pin 10, and the crankshaft rotates.

As shown by the black arrow in FIG. 3, the cooling liquid for the quenching coil 20 is divided into two and supplied to the supply pipes 61A and 61B. One of them is the feeding coil 23 and the first heating coil 21.
After cooling these coils through the left half of the drawing in FIG.
2 and the other one is discharged from the discharge pipe 63 through the power feeding coil 23, the right half of the first heating coil 21 in the figure, and the connection coil 26. In addition, the cooling liquid supplied to the supply pipe 61B passes through the power supply coil 24, the left half of the second heating coil 22 in the drawing, the connection coil 25, and the discharge pipe 62 according to the above description, and the other is the power supply coil 24, the second heating coil It is discharged from the discharge pipe 63 through the right half of 22 in the figure.

Further, as shown by the white arrow in FIG. 3, the high frequency current is divided into two parts from the feeding coil 23 to the left and right, and flows through half of each of the first and second heating coils 21 and 22 and one of the connecting coils 25 and 26. , And returns to the power source 40 via the power feeding coil 24. The surface 11 of the pin 10 has the first and second heating coils 2
1, 22 and the connecting coils 25, 26 are heated by an induction current induced by a high frequency current.

Therefore, the quenching coil 20 has a reduced impedance as well as an impedance, and a large current can be passed therethrough, and a large power can be obtained.

Further, the cooling liquid flow path is approximately 1/2 of that of the conventional quenching coil, so that the cooling effect can be enhanced.
Therefore, the temperature rise can be made lower than that of the conventional quenching coil, so that the degree of deterioration thermal fatigue is reduced and the occurrence of cracks caused by the decrease in mechanical strength accompanying the progress of deterioration can be prevented. You can Therefore, the life of the quenching coil can be extended.

The central portion of the surface 11 has the first and second portions.
The distance D between the heating coils 21 and 22 is narrowed, and the distance between the feeding coils 23 and 24 is also narrowed accordingly. Further, since the current directions of the central portions are opposite to each other, the spacer 65 is not heated by the induced current. The operation of the core 60 is the same as that described in the related art, and the description thereof is omitted.

As described above, the core 60 is provided on the first and second heating coils 21 and 22 and the connecting coils 25 and 26. However, in order to make the flow paths of the cooling liquid uniform, the discharge pipes 62, 63 are provided in the central portions of the connection coils 25, 26.
, The installation location of the core 60 is the connection coil 25,
Since it cannot be located at the center of the pin 26, there arises a problem that it is difficult to uniformly heat the surface of the pin 10.

Therefore, as shown in FIGS. 1 and 3, the discharge pipe 6
The connection positions of 2, 63 are set to the first and second heating coils 21, 2,
While connecting to the opposite ends A and B of 2,
The core 60 is provided so as to be located substantially in the center of the connecting coils 25 and 26. That is, the end portions A and B are the quenching coil 2
It is symmetrical with respect to the center point C of 0.

When the discharge pipes 62 and 63 are connected as described above, the flow path of the cooling liquid becomes long and short, and the cooling liquid does not flow evenly through each coil. Therefore, the sizes (cross-sectional areas) of the first and second heating coils 21 and 22 and the connecting coils 25 and 26 are changed and supplied, and the discharge pipes 62, 62 are supplied from the pipes 61A and 61B.
The cooling liquid is made to flow evenly through each of the paths leading to 63.

In this embodiment, grooves are formed by changing the width in the lateral width direction of the inner surface of the hollow portion of the coil, the coil having a longer water channel has a larger width of the groove 30, and the coil having a shorter water channel has a width of the groove 30 increased. The problem is solved by making it small.

[0038]

As described above, in the quenching coil of the present invention, both ends of the first and second heating coils in which the annular surfaces formed on the surface of the object to be quenched are connected in parallel are connected by the connection coil. The power feeding coil forms two parallel circuits.

Then, the substantially central portions of the first and second heating coils are connected to a power source and a cooling liquid supply port to heat each coil, and at the same time, the reciprocal of the connecting coils which are symmetrical with respect to the center of the quenching coil. The cooling liquid discharge pipe is provided at the end of the connecting coil, and the core is provided at the center of the connecting coil. Further, in the vicinity of the central portions of the first and second heating coils, the facing distance interval is arranged to be narrower than that of the other portions.

Therefore, the quenching coil has a small impedance and can obtain a large power. Further, the cooling liquid passage is halved compared with the conventional one, so that the cooling effect of the coil is enhanced and the life of the quenching coil is extended.

Further, since the spacer located at the central portion is not heated by the induced current, the spacer is not heated to a high temperature and the safety of the quenching apparatus is improved.

[0042]

[Brief description of drawings]

FIG. 1 is a schematic external perspective view of a quenching coil according to the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a plan view illustrating a current passage of a quenching coil in a current cooling unit.

FIG. 4 is a schematic external perspective view of a quenching coil according to a related art.

5 is a view taken along the line BB of FIG.

FIG. 6 is a front view of a main portion of an induction hardening apparatus for explaining a state where an induction coil is placed on a portion to be hardened.

[Explanation of symbols]

 10 pins 20 half-open induction hardening coil 21 1st heating coil 22 2nd heating coil 23 feeding coil 24 feeding coil 25 connecting coil 26 connecting coil 40 power supply 60 core 61A, 61B supply pipe 62 discharge pipe 63 discharge pipe 64 coil Side plate 65 Spacer

Claims (2)

[Claims] 1. An arc-shaped portion of a substantially semi-circular shape or a circle smaller than the semi-circular shape, which is arranged in the upper part of an annular hardened surface of a hardened object and is close to the hardened surface. The first heating coil having a hollow shape and the first heating coil have substantially the same shape, and are arranged to face the first heating coil at a predetermined interval and close to the surface to be hardened. A second heating coil,
A pair of hollow feeding coils having one ends connected to substantially central portions of arc portions of the first and second heating coils;
A pair of hollow connection coils connecting both ends of the heating coil, a cooling liquid supply pipe connected to the other end hollow part of the power feeding coil, and cooling connected to the first and second heating coils. A liquid discharge pipe; and a core formed so as to cover the surfaces of the first and second heating coils and the connection coil that do not face the hardened surface, and the first and second cores A semi-open induction hardening coil, characterized in that the vicinity of the central part of the arc portion of the heating coil is arranged narrower than the predetermined distance interval and a high frequency voltage is applied between the other ends of the feeding coil. . 2. The cooling liquid discharge pipe is provided at opposite ends of the first and second heating coils, and the cooling liquid is provided in hollow portions of the first and second heating coils and the connection coil. The semi-open induction hardening coil according to claim 1, wherein the cooling liquid is made to flow evenly in each of the coils by forming grooves having different widths depending on the length of the flow path.