JPS6199624A - Quenching apparatus - Google Patents

Abstract

PURPOSE:To perform high frequency quenching at inner surface of small hole efficiently, by inserting an adjacent conductor in a small hole of body to be quenched to heat it by high frequency conduction, and supplying quenching cooling water therein spirally in fluid state. CONSTITUTION:A quenching apparatus 10 is composed of a unit conductor 14, the first and second contact electrodes 18, 26, the adjacent conductor 30 arranged near inner surface of the small hole 2, a means 38 for supplying cooling water to hollow part thereof, a high frequency source 16 and means 34, 35 for supplying quenching cooling water. Said conductor 14 is composed of the first conductor 11, second conductor 12 and electrical insulating material 13 interposed between them. Said means 34, 35 are arranged at a prescribed angle to fluidize quenching cooling water spirally between inner surface of the hole 2 and the conductor 30.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to an apparatus for hardening the inner surface of a small hole in a body to be hardened by high frequency direct current hardening.

b. Prior Art Conventionally, induction hardening of the inner surface of a small hole has been carried out using an apparatus as shown in FIG. The induction hardening apparatus shown in FIG. 5(A) uses a copper vibrator 1 having a hollow part 1a for water cooling, and uses a multi-turn coil 3 according to the inner diameter and wall thickness T of a small hole 2 to be hardened. The coil 3 is inserted into the small hole 2, the inner surface 2a of the coil 3 is heated by high frequency induction, and then hardened by rapid cooling. However, in the case of this hardening device, in order to supply a large current to the copper vibrator 1, it is necessary to use a diameter of 2111φ or more, so if the inner diameter of the small hole 2 is about 8 fl or less, the hollow part 1a is It becomes impossible to wind the water-cooled copper vibrator into a coil.

Further, the induction hardening apparatus shown in FIG. 5(B) uses a so-called hairpin type coil 4, but even in this case, when the inner diameter of the small hole 2 becomes about 7 mm or less, the coil 4
This creates dimensional limitations in the production of.

Therefore, in the past, the coils 3 and 4 shown in FIGS.
When heating a small hole with the following dimensions for hardening,
As shown in FIG. 5(C), annular coils 6a and 6b are installed around the small hole 2 and on both upper and lower end surfaces 5a and 5b of the object to be hardened 5.
were placed in each chamber and subjected to high-frequency induction heating.

C1 Problem to be Solved by the Invention However, in the device shown in FIG. 5(C), the inner surface 2a of the small hole 2
In this method, the object to be quenched 5 is heated from the upper end surface 5a side and the lower end surface 5b side, heated to the center of the inner surface 2a of the small hole 2 by heat conduction, and then quenched and cooled.
The hardened layer pattern 7 is located near the upper and lower end surfaces 5a and 5b as shown in FIG. 5(C).

It becomes deep at F 8b and becomes shallow at the central point 9.

Therefore, this apparatus has the disadvantage that it is not possible to obtain a uniform hardened layer pattern. In particular, when the wall thickness T of the object to be quenched 5 becomes large, heating from both the upper and lower end surfaces 5a and 5b takes time to heat up to the central part 9, resulting in poor work efficiency, and furthermore, the quench hardened layer pattern In addition, the degree of nonuniformity of the inner surface 2a of the small hole 2 increases, and the amount of deformation of the inner surface 2a of the small hole 2 also increases. Due to these circumstances, there is a limit to the amount of material to be quenched 5 that can be quenched using this apparatus.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide an apparatus that can efficiently and effectively perform induction hardening of small diameter holes that are difficult to perform good induction hardening with conventional methods. It is about providing.

Means for Solving Problem d1 In order to solve the above-mentioned problem, in the present invention, in an apparatus for hardening the inner surface of a small hole in a body to be hardened by high-frequency direct current hardening, <A> a first conductor; and a second conductor with an electrical insulator interposed between them; <B) a first contact electrode connected to the first conductor and disposed in contact with one end surface of the object to be hardened; and <C> a second contact electrode connected to the second conductor and placed in contact with the other end surface of the object to be quenched; and <D> connected to the second conductor and arranged in contact with the first contact electrode. a proximal conductor disposed close to the inner surface of the small hole between the second contact electrode; (E) cooling water supply means for supplying cooling water to the hollow part of the proximal conductor; <F> the first s a high frequency power source connected between the body and the second conductor; <G) w between the inner surface of the small hole and the outer surface of the adjacent conductor;
In order to cause the quenching cooling water to flow into the lance in a spiral manner, quenching cooling water supply means arranged at an angle oblique to a direction perpendicular to the axis of the small hole; I have to.

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 4.

1 and 2 show the configuration of a hardening device 10. This device 10 consists of a plate-shaped first conductor 11 and a second conductor 1.
A unit conductor 14 is provided with an insulating plate 13 interposed between the unit conductor 14 and the unit conductor 14, which is fixedly arranged on a device base 15. And the above-mentioned first and second conductor 1
A high frequency power source 16 is connected between 1 and 12 via a lead wire 17.

Further, a first contact electrode 18 made of chromium copper or the like is arranged in association with the unit conductor 14. That is, the first contact electrode 18 is placed on the insulating plate 13 at one end of the unit conductor 14 and is fixed by brazing or the like while being electrically connected to one end surface of the first R body 11. has been done. As shown in FIG. 1, the first contact electrode 18. Through holes 19, 20, 21 are formed in the unit conductor 14 and the device base 15, respectively.
21 are in communication with each other.

Further, a branch passage 22 communicating with the above-mentioned through hole 19 is formed in the first contact TL pole 18, and a quenching cooling water discharge vibe 23 connected to this branch passage 22 is disposed. Furthermore, a cooling water drainage vibe 24 connected to the above-mentioned through hole 21 is disposed on the four-piece base 15 .

Further, in FIGS. 1 and 2, 26 is a second contact electrode made of chromium copper or the like, and a central through hole 29 having two stepped portions 27 and 28 is formed in the center thereof. A proximity conductor 30 having an annular cross section is integrally attached to this second contact electrode. That is, the above-mentioned proximity conductor 30 is constituted by a hollow cylindrical body having external dimensions such that it is disposed close to the cylindrical inner surface 2a of the small hole 2 of the object to be hardened 5, and the upper end 30a thereof is connected to the second contact electrode. It is fitted and fixed to the stepped portion 28 of 26 and electrically connected.

Furthermore, as shown in FIGS. 1 and 2, the side wall portion of the second contact electrode 26 is provided in a vertical direction (that is, in the axial direction of the small hole 2) from the outer peripheral portion 32 toward the inner peripheral surface 33. A quenching cooling water supply hole 34 is formed at an angle of, for example, 30° to 45° with respect to the direction perpendicular to the direction. A quenching cooling water supply pipe 35 extending in the same direction as the supply hole 34 is connected to the outer peripheral surface 33 of the second contact electrode. In addition, this quenching cooling water supply hole 34 and pipe 35 are
As shown in FIG. 2, they are disposed at two locations on the side wall of the second contact electrode 26 facing each other by approximately 180 degrees, and are arranged in an annular region between the inner surface 2a of the small hole 2 and the proximal conductor 30. They are each oriented in the tangential direction of S.

Further, a fixed plate 36 is integrally fixed to the upper surface 26a of the second contact electrode 26, and a passage 37 communicating with the central through hole 29 of the second contact electrode 26 is formed in the fixed plate 36. ing. A cooling water supply pipe 38 is provided on the stationary plate 36 so as to communicate with the passage 37. Thus, the second contact electrode 26° proximal conductor 30 and the fixed plate 36 are integrally connected to each other, and can be raised and lowered by the lifting cylinder 39.

Although not shown, the upper and lower surfaces of the first and second contact electrodes 18.26 (i.e., the contact surfaces 41, 42)
) is provided with a copper O-ring in order to make good contact with the object to be hardened 5 and prevent wear.

Next, the operation of the induction hardening apparatus 10 of this example will be explained.

First, the object to be hardened 5 having the small hole 2 to be hardened is placed on the first contact electrode 18, and the small hole 2 is placed on the first contact electrode 18.
8 to match the center through hole 19 of No. 8. Thereafter, by operating the lifting cylinder 39, the fixed platen 36. The assembly consisting of the second contact electrode 26 and the proximal conductor 30 is lowered, and the proximal conductor 30 is inserted into the small hole 2 of the object to be quenched 5 from above. As a result, as shown in FIG. 1, the proximal conductor 30 is coaxially arranged close to the inner surface 2a of the small hole 2, and the lower end thereof! ) Ob passes through the central through hole 19 of the first contact electrode 18 and is electrically connected to the second conductor 12 . Along with this, the object to be hardened 5 is sandwiched between the first and second contact electrodes 18.26, and the object to be hardened 5 is held between the first and second contact electrodes 18.26.
Second and first contact electrodes 2 are provided on the upper end surface 5a and the lower end surface 5b.
The contact surfaces 42, 41 of 6°18 are respectively crimped.

Therefore, the first and second contact electrodes 18,26 are connected to the object to be hardened 5 as described above, and the cooling water supply pipe 38, the passage 37 of the fixed plate 36, the second contact electrode 26 The central through hole 29. The hollow portion 31.1 of the adjacent conductor 30! The through hole 21 of the mounting base 15 and the cooling water discharge pipe 24 are communicated with each other to form one communication path.

Under this condition, when a high frequency current is supplied from the high frequency power source 16 to the unit conductor 14, the high frequency current passes from the first conductor 11 through the first contact electrode 18 as shown by the arrow in FIG. The inner surface 2a of the small hole 2.

Second contact electrode 26. It flows sequentially through the outer surface of the proximal conductor 30 and the second conductor 12 to the high frequency power source 16, or alternatively flows through the opposite path. In FIG. 1, the current supplied from the high-frequency power source 16 is expressed as 'I+the current flowing through the inner surface 2a of the small hole 2 of the object to be hardened 5 as i,', and the current flowing through the adjacent conductor 30 as 12. ing.

A current i flowing along the inner surface 2a of the small hole 2 of the object to be hardened 5,
r and the current 12 flowing through the adjacent conductor 30 are attracted to each other so that the generated magnetic flux is minimized, and the current density is distributed so that they flow close to each other. In addition, the object to be quenched 5
Since one coil is formed by the inner surface 2a of the small hole 2 and the adjacent conductor 30, an induced current also flows through the inner surface 2a of the small hole 2.

FIG. 3 shows details of the current flowing through the inner surface 2a and the adjacent conductor 30. That is, in the inner surface 2a, there is a composite current 11'' (
(not shown) flows, and the inner surface 2a is uniformly heated by high-frequency induction.

At this time, in order to prevent heating of the adjacent conductor 30, cooling water is supplied to the hollow portion 31 of the adjacent conductor 3o via the pipe 38 and is discharged to the outside through the pipe 24.

Next, when the inner surface 2a reaches a predetermined quenching temperature, the current supply from the high frequency power source 16 is cut off, and quenching cooling water is supplied through the quenching cooling water supply pipe 35 and the quenching cooling water supply hole 34. It is supplied into the region S between the inner surface 2a of the small hole 2 of the object to be hardened 5 and the adjacent conductor 30. In this case, as described above, the quenching cooling water supply hole 34 is inclined with respect to the axis of the small hole 2 and is arranged in the tangential direction of the region S, so that the quenching cooling water is supplied to the first As shown by the imaginary line A in the figure, the inner surface 2 is rapidly cooled while flowing spirally between the inner surface 2a of the small hole 2 and the adjacent conductor 30, and the quenched hardened layer 44 ( (see FIG. 4) is formed. Note that the water pressure of the quenching cooling water supplied to the pipe 35 is, for example, 3 kg/c.
11, and the flow rate is, for example, 900 to 1000c.
c/sec.

According to the induction hardening apparatus 1o of this example configured as described above, one proximal conductor 3o having a hollow portion 31 is inserted into the small hole 2 to perform high-frequency induction heating. It can be used for quenching small holes 2 of ~8 diameter or less, and since the quenching cooling water is made to flow in a spiral shape, the quenching cooling water can be made to flow efficiently and smoothly. Rapid cooling of the inner surface 2a is possible. For this reason,
Even if the small hole 2 has a diameter of 7 to 8 mφ or less, the inner surface 2a thereof can be efficiently hardened by a simple operation, and a uniform hardened layer pattern can be obtained.

Further, in this example, as clearly shown in FIG.
Edges 49a of the upper and lower portions of the small hole 2 where eddy currents tend to concentrate because of the step portions 46 and 47 formed therein.

49b, 49c, and 49d can be prevented from overheating, and the inner surface 2c of the small hole 2 can be uniformly heated and, as a result, uniformly hardened. Note that even if the size of the stepped portions 46 and 47 is small, the above effect can be sufficiently achieved;
It may be about a~0.2 conductor.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment;
Various modifications and changes are possible based on the technical idea of the present invention.

For example, in the above embodiment, two quenching cooling water supply pipes 35 are used, but the number may be one, or three or more pipes may be arranged equally spaced. You may also do so. In addition, it is not limited to the round small hole 2,
The hardening apparatus of the present invention can also be used for small holes such as square or hexagonal.

C9 Effects of the Invention As described above, the quenching apparatus of the present invention performs high-frequency induction heating by inserting and arranging a proximal conductor into the small hole of the object to be quenched, and heats the object through the angled quenching cooling water supply pipe. This device has an extremely simple structure because it is configured to supply quenching cooling water between the inner surface of the small hole and the outer surface of the adjacent conductor, causing it to flow in a spiral pattern and rapidly cooling the inner surface. Despite this, it is possible to create small holes (e.g. 7 to 8
It is possible to efficiently perform induction hardening on the inner surface of a diameter (up to uφ), and to obtain a uniform hardened layer pattern. Therefore, according to the hardening apparatus of the present invention, it is possible to significantly improve work efficiency, shorten work time, and reduce product cost.

[Brief explanation of the drawing]

1 to 4 show one embodiment of the present invention, in which FIG. 1 is a sectional view of an induction hardening apparatus according to the present invention, and FIG.
The figure is a sectional view taken along the line ■-■ in Fig. 1, Fig. 3 is an enlarged sectional view of the main part schematically showing the current flowing through the inner surface of the small hole of the object to be hardened and the adjacent conductor, and Fig. 4 is a sectional view of the small hole in the object to be hardened. A cross-sectional view showing a hardened layer pattern formed on the inner surface of the hole, FIG. 5(A),
(B) and ('C) are main part sectional views showing conventional induction hardening equipment, respectively. 2...Small hole, 2a...Inner surface, 5...
... Hardened object, 5a... Upper end surface, 5b.
...lower end surface, 10...quenching device, 11
...First conductor, 12...Second conductor, 1
3... Insulating plate, 14... Unit conductor,
16... High frequency power supply, 18... First contact electrode, 23... Quenching cooling water discharge pipe, 24... Cooling water discharge pipe, 26... Second contact electrode, pole, 30 ... Proximity conductor, 31... Hollow part, 34... Quenching cooling water supply hole, 35... Quenching cooling water supply pipe, 38... Cooling water supply pipe, 39... Lifting cylinder, 41, 42...contact surface, 44...
Quench hardened layer. Figure 2 S l'j Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] In an apparatus for hardening the inner surface of a small hole in a workpiece by high-frequency direct current hardening, <A> a unit formed by interposing an electrical insulator between a first conductor and a second conductor; a conductor, <B> a first contact electrode connected to the first conductor and placed in contact with one end surface of the object to be hardened; <C> connected to the second conductor and placed in contact with one end surface of the object to be hardened; a second contact electrode placed in contact with the other end surface; <D> connected to the second conductor and placed close to the inner surface of the small hole between the first contact electrode and the second contact electrode; <E> A cooling water supply means for supplying cooling water to the hollow part of the adjacent conductor; <F> A high frequency power source connected between the first conductor and the second conductor; G> In order to cause the quenching cooling water to flow spirally in the area between the inner surface of the small hole and the outer surface of the adjacent conductor, the small hole has an angle inclined with respect to a direction perpendicular to the axis of the small hole. A quenching apparatus comprising: a quenching cooling water supply means arranged therein; and quenching cooling water supply means.