JPS61195923A - Method and device for hardening surface of shaft member having small hole opened to peripheral surface - Google Patents

Abstract

PURPOSE:To avert the overheating and overcooling around a small hole and to harden uniformly the surface of a shaft member by closing one end of the through-hole of the shaft member, introducing fluid therein and heating and cooling quickly the shaft member while ejecting the fluid through the opening on the peripheral surface of the shaft member. CONSTITUTION:The shaft member W is fitted between center shafts 20 and 50 and a closing member 60 is brought into press contact with the other end face of the shaft member W. A driving shaft 11 is turned to rotate the member W. A prescribed flow rate of gas is admitted into a passage 33 and is ejected from the aperture on the peripheral surface through the through-hole or blind holes Ha-Hc and small hole (h) of the shaft member W. The member W is subjected to induction heating by a heating coil so that the surface layer is heated up to the prescribed hardening temp. The cooling fluid for hardening is then injected and to cool quickly the surface layer. The injection of the fluid from the aperture on the peripheral surface of the hole (h) is continued during this time. The hardened layer having the uniform hardness distribution down to the uniform depth is formed over the entire surface on the peripheral surface of the part to be treated of the member W.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method and apparatus for induction hardening the surface of a shaft member having small holes such as oil holes in the circumferential surface.

(Prior art) The surface of shaft members is often subjected to hardening treatment in order to improve their mechanical properties. Particularly when a predetermined portion of the curved surface is used as a sliding surface, surface hardening treatment is performed to impart wear resistance. Although this can be said to be essential, oil holes are often opened to supply lubricating oil to the sliding surface.

Conventionally, when induction heating hardens a shaft member that has small holes such as oil holes on its surface, magnetic flux concentrates around the openings of the small holes due to the edge effect, which is a characteristic of induction heating, during heating. The temperature is abnormally high compared to other parts, and the ridge line part is easily cooled during rapid cooling, so the deep part is cooled excessively compared to other parts, and this causes a breakdown in the internal stress of the member, resulting in quench cracking. Even if it does not lead to quench cracking, it may cause excessive quenching and make it impossible to obtain a uniform quenched finish, so a steel plug member may be fitted into the small hole,
They were filled with magnetic material powder and then hardened.

(Problems with conventional technology) As a pre-quenching process, plug members are fitted into small holes,
The work of filling the magnetic material powder and the work of extracting the plug member and magnetic material powder from the small hole as a post-quenching process must all be done manually, and in addition, the plug member is removed from the small hole after the hardening process. It is not easy to pull out the hole because it is shrink-fitted, and if the plug member does not completely seal the small hole (which is normal), the cooling fluid for quenching (an aqueous solution of a water-soluble resin agent) is used. Magnetic material powder must be used with care, as it will enter the small hole and adhere to the hole wall during heating, and if it is not removed with a small wire brush after the hardening process, it will cause rust. Since scissors pieces remain in the hole, it is extremely complicated and time-consuming, and lacks productivity, so a solution has been desired.

(Object of the Invention) The present invention has been made to solve the problems that exist in the conventional method when surface hardening a shaft member having small holes in the circumferential surface. By avoiding overheating and overcooling of the periphery of the small hole, it is possible to obtain the same quenched finish as other parts with no risk of quench cracking, and moreover, it is possible to achieve the same hardening finish as other parts, and to prevent cracking of the through hole or blind hole and the wall of the small hole. The purpose of the present invention is to provide a quenching method and device that eliminates the risk of rust and oxidation.

(Configuration of the first invention) The configuration of the first invention of the present application is as follows: (1) A through hole drilled along the axis from one end surface to the other end surface or a blind hole drilled from one end surface to a predetermined position branches. When induction heating and hardening the circumferential surface of a shaft member in which a small hole opens into an open surface, (2) gas is introduced into the hole from one end surface of the through hole that is closed, or from the hole end surface of the blind hole; (3) A shaft having small holes in its circumferential surface, characterized in that: (3) the gaseous fluid is ejected from an opening in the circumferential surface, and is heated by a heating coil and rapidly cooled by a cooling fluid for quenching; There is a method for surface hardening of parts.

In other words, a through hole or a blind hole provided along the axis of the shaft member that serves as a lubricating oil supply path is used, and in the case of a through hole, the hole opening on the other end side is closed and the hole on one end side is closed. A gaseous fluid is caused to flow into the hole from the hole opening, or from the hole opening on the end face in the case of a blind hole, and is jetted out from a small hole that branches from the through hole or blind hole and opens on the peripheral surface. It is subjected to a quenching process.

(Effect of the first invention) During heating in the quenching process, the gaseous fluid ejected from the small holes opened in the peripheral surface concentrates magnetic flux due to the edge effect, absorbs heat from the overheated periphery of the opening, and lowers the temperature of other parts. The heating temperature is maintained at the same temperature as , and during cooling, the quenching cooling fluid is prevented from entering the hole, thereby preventing overcooling by the quenching cooling fluid from the hole wall side.

(Configuration of the second invention) The configuration of the second invention of the present application regarding a device for embodying the idea of the first invention of the present application is as follows: (1) A through hole or one end surface that is bored along the axis from one end surface to the other end surface. In an apparatus for induction heating hardening of the circumferential surface of a shaft member in which a small hole branching from a blind hole drilled to a predetermined position is opened on the circumferential surface, (2) the shaft member is A center shaft that holds and rotates the member from both end faces, (3) one side is a solid part in the direction of the 40 yuan part, and a predetermined outer diameter that is formed into a hollow tubular part for a predetermined length from the tip face. σ-shaft material, B. The outer periphery of the center shaft in the base direction is covered with a fixed case in which an annular circumferential groove is formed inside so that the center shaft can rotate and maintain airtightness, and C. The tip part A two-stage inner diameter with a predetermined length portion as a large inner diameter portion into which one end of the shaft member can be inserted, and the remaining portion into a small inner diameter portion into which the center shaft can be inserted and whose diameter includes the hole position on the end surface of the shaft member. The shaft member support tube is fixedly arranged so that the center shaft end face is located within the small inner diameter portion, and (4) the other side is formed into a cone shape so that the tip can be inserted into the center hole on the other end face of the shaft member. (b) a cylindrical closing member having an end surface that can come into contact with substantially the entire surface of the other end surface of the shaft member is fixedly disposed on the outer periphery excluding the cone-shaped tip; (5) of the center shaft on one side; The inside of the tubular part and the circumferential groove of the case are communicated through a through hole, and (6) a small groove is formed on the circumferential surface, the circumferential groove being set such that a passage connected to the gas supply source opens in the circumferential groove. There is a surface hardening device for a shaft member in which a hole is opened.

(Example) The second invention of the present application will be described in detail below according to the example shown in FIG.

In the figure, W is a shaft member, 10 is a drive shaft part, 20
1 is a center shaft on one side, 30 is a case that covers the outer periphery of the center shaft 20 in the direction of the base, 40 is a shaft member support tube, 50 is a center shaft on the other side, and 60 is a closing member.

The shaft member W has a large inner diameter of 1 from one end surface to the other end surface.
(a) Holes with different diameters, medium-thickness IHb and small internal diameter Hc, are drilled along the axis, forming a through-hole H that is bent in the middle or communicates, and the through-hole H has a predetermined position. There is a small hole that branches out from the top and opens on the circumference.

The drive shaft section 10 is the same as that of a normal shaft member hardening machine, and the drive shaft 1 is supported by a bearing 12 via a bearing group 13 and rotated by a rotary drive source (not shown).
1, an insertion hole 14 with a predetermined inner diameter is bored in the tip end face of the drive shaft 11, a threaded portion 15 is formed on the outer periphery of the tip, and a tightening cap is provided with a through hole with a predetermined inner diameter on the end face. 16 can be screwed together.

The one-side center shaft 20 of the present invention is inserted up to the collar 21 into the insertion hole 14 of the drive shaft portion IO, and is secured by a cap 16, and is rotatable as the drive shaft portion 10 rotates. be. The center shaft 20 on one side has a solid portion 22 . A hollow tubular portion 23 is formed at a predetermined length from the distal end surface.

The case 30 has one end face fixed to the end face of the bearing 12 so as to be coaxial with the center shaft 20 on one side, and is tightened from the cap 16 to the tubular portion 20 of the center shaft 20 on the one side.
It consists of a cylindrical body with a length that can include up to a predetermined range of. The end face of the case 30 in the direction of the bearing 12 and the drive shaft 11 and the end face in the tip direction are each provided with an oil seal 3.
1, and the inner wall of the case 30 and the center shaft 20 on one side
For example, ball bearings 32a and 32b are fitted into the space formed between the outer periphery and the outer periphery of the ball bearings 32a and 32b while maintaining a predetermined spacing S. Therefore, the center shaft 20 is
It is surrounded by a circumferential groove formed by the spacing S between the bearings 32a and 32b, and is rotatable within the case 30 while maintaining airtightness.

Thus, the circumference m of the tubular portion 23 of the one-way center shaft 20 is
On the one hand, the specifications are set so that the part surrounded by providing a passage 33 that opens to a predetermined position;
A conduit that connects to a gas supply source (not shown), such as an air compressor, is connected to the passage 33 so as to be connectable thereto.

The shaft member supporting tube 40 has a predetermined length portion having a large inner diameter portion 41 into which one end of the shaft member can be fitted. The remaining part is made of a tubular material with a two-stage inner diameter formed into a small inner diameter part 42 into which the one-way center shaft 20 can be inserted, and the end face is at a predetermined distance from the large inner diameter part 41 at the tip of the one-way center shaft 20. The screw hole 43 is used to securely tighten the screw hole 43 so that the portion K is maintained within the small inner diameter portion 42 . Therefore, the inner diameter of the small inner diameter portion 42 must be set to a size that includes at least the opening of the through hole H located at any position on one end surface of the shaft member W.

The center shaft 50 on the other side has an integral structure with the closing member 60, and is equipped with a forward/backward movement mechanism (not shown), and is movable toward and away from the one-way center shaft 20, and A displacement shaft 51 that is supported by a bearing (not shown) and can freely rotate; a closing member 60 having a stepped through hole 62 fixedly arranged with a bolt using a threaded hole 61 at the tip of the displacement shaft 51; A cone shaft 52 in which a main body having a cone-shaped tip 521 (conical shape) is inserted into the smallest inner diameter portion of the hole 62 located in the direction of the end face facing the center shaft 20, and the flange portion 522 is in the small inner diameter portion.
, a compression coil spring 53 is inserted between the end surface of the displacement shaft 51 in contact with the step of the medium diameter portion of the closing member 60 and the end surface of the flange portion 522 of the cone shaft 52.

The end face of the closing member 60 is formed to have substantially the same shape as the other end face of the shaft member W. Further, the cone 521 of the cone shaft 52 is formed to be insertable into a center hole on the other end surface of the shaft member W.

When the displacement shaft 51 is displaced in a direction away from the one-way center shaft 20, the compression coil spring 53 is expanded and the flange 522 is brought into contact with the step of the minimum inner diameter part, so that the cone shaft 5
When the cone 521 is inserted into the center hole of the shaft member W by making the tip of the cone 521 sufficiently protrude from the end surface of the closing member 60 and moving toward each other, the cone shaft 52 presses the other end surface of the shaft member W. The compression coil spring 53 is compressed by the retreat of the cone shaft 52, as shown in the figure (the flange 522 is separated from the step at the innermost diameter part, and in this state, the other end surface of the shaft member W and the end surface of the closing member 60 are separated from each other). The specifications are set so that the pressure contact is made by the urging force of the compression coil spring 53.

The case of hardening a shaft member W having a small hole in its shoulder surface using the apparatus having the configuration of the above embodiment will be described below.

A shaft member W is carried in between the two center shafts 20.50 in which the other side center shaft 50 is displaced in a direction away from the one-sided center shaft 20, and the carried shaft member W is axially moved to the right in the figure. by moving one end to the large inner diameter portion 4 of the shaft member support tube 40.
1 until the end surface comes into contact with the step.Then, the forward/backward mechanism is driven to displace the displacement shaft 51 of the other center shaft 50 in the direction toward the other center shaft 50. As a result, the closure member 60 is attached to the attached cone shaft 52. The cone 52 moves forward toward the other end surface of the shaft member W accompanied by the compression coil spring 53.
1 is inserted into the center hole provided on the other end surface of the shaft member W, and the shaft member W is supported in cooperation with the one-way center shaft 20 while being pressed in the direction of the one-way center shaft 20. In this state, the end surface of the closing member 60 is in pressure contact with the other end surface of the shaft member W.

As described above (when the shaft member W is supported by the one side center shaft 20 and the other side center shaft 50, the passage 33 of the case 30 is connected to the circumferential groove S, the through hole 24 of the one side toilet shaft 20, and the inside of the tubular part 23. 231 and the predetermined interval part K in the small inner diameter part 42 of the shaft member support tube 40, it communicates with the hole opening of the large inner diameter part Ha on one side of the through hole H of the shaft member W, but in the direction of the other end of the through hole H. Since the hole opening of the small inner diameter portion Hc located at The Rukoto.

Next, the drive shaft 11 is rotated by operating a rotary drive source (not shown), and gas adjusted to a predetermined flow rate per unit time flows into the passage 33 from a gas supply source (not shown) via the conduit. The shaft member W rotates while being supported by the center shaft 20 on one side, which rotates with the rotation of the drive shaft 11, and the center shaft 50 on the other side, without rotating freely, and the gas flowing in from the passage 33 is transferred to the rotating shaft member W. It is ejected from the opening in the peripheral surface via the through hole H.

In this state, the shaft member W is subjected to induction heating using, for example, a branch-shaped heating coil, and the shaft member W whose surface layer has been heated to a predetermined quenching temperature by the induction heating is provided with a cooling jacket at a predetermined position. The shaft member W is moved into a cooling tank filled with a cooling fluid for quenching, while the center shafts 20.50 maintain the rotation and gas supply state using a predetermined moving mechanism. The material is rapidly cooled and quenched by immersion. During this time,
Gas continues to be ejected from the opening on the circumferential surface of the small hole, and due to the action described above in connection with the first invention of the present application, the opening periphery is prevented from overheating during heating and subcooling during rapid cooling, and the shaft member W is prevented from overheating during heating and overcooling during rapid cooling. A hardened layer having a uniform hardness distribution to a uniform depth is formed over the entire surface of the treated part.

The shaft member W, which has been hardened as described above, is released from the supported state by the displacement of the other side center shaft 50 in the direction away from the one-way center shaft 20, and is carried out.

(Other Embodiments) In the above embodiment, the one-way center shaft 20 is placed on the drive shaft 11 side,
Although the configuration has been described in which the other side center axis 50 is set on the displacement axis side, there is no problem even if this is set in the opposite direction.

Further, the configuration inside the case 30 is not limited to the above embodiment, and the tubular portion 23 of the center shaft 20
1, and the one-way center shaft 20 can be rotated while maintaining airtightness, and any structure that satisfies this condition falls within the scope of the design of the present invention.

Further, a closing member 6 fixedly arranged on the other side center shaft 50
0, as shown in FIG.
02, and an elastic body such as a disc spring 63 is inserted between both members 601 and 602 to give the closing plate 602 elasticity in the same way as the cone shaft 52, so that the shaft member W is heated and cooled. The closing action may be performed while the cone shaft 52 follows the expansion/contraction behavior that sometimes occurs.

In the above embodiment, the shaft member W is provided with a through hole H, but even if the shaft member W is provided with a blind hole along the axis line, the shaft member W may have a blind hole. The end surface with the opening of the hole may be fitted into the shaft member support tube 40 fixedly disposed at the tip of the center shaft 20 on one side (in this case, the center shaft 50 on the other side may be fitted with the shaft member support tube 40 of the present invention). A normal cone shaft for shaft member hardening may be used without using the closing member 60 or the closing plate 602, which form part of the shaft member, or the hardening process may be performed with the structure of the present invention as it is.

In addition, the gas used in the present invention may normally be air, but if necessary, an inert gas may be used to prevent through holes, blind holes, and small holes from oxidizing during hardening. good.

The flow rate of the fluid ejected from the opening of the small hole can be adjusted as long as the heat removal of the superheat during heating of the periphery of the opening and the prevention of the cooling fluid from entering the small hole during cooling are achieved. It's not something to ask.

Furthermore, it is also possible to control the heating in the vicinity of the small hole opening during heating by the cooling capacity of the selected gas.

In the present invention, if the design specifications are appropriately changed, the method for hardening the shaft member W can be one-shot hardening using saddle-shaped heating coils facing each other over substantially the entire axial length to a predetermined length, or one-shot hardening over substantially the entire axial length to a predetermined length of the shaft member W. One-shot hardening and moving hardening using a multi-turn heating coil that covers the surrounding surface.

Of course, it is applicable to all cases, such as moving hardening using a single-turn heating coil, and stationary hardening at one or more locations where small holes are opened using one or more single-turn heating coils.

(Effects of the Invention) By applying the method and apparatus of the present invention to the surface hardening of a shaft member having small holes in its circumferential surface, (1) the shaft member covers the entire circumferential surface to be treated including the periphery where the small holes are formed; A uniform quenching finish is guaranteed, and (2) the pre-process of inserting or packing the plug member and magnetic powder into the small hole, and the post-process of extracting or removing them from the small hole and other post-processes are required. Labor-saving has been achieved by completely eliminating the need for extremely complicated, time-consuming and manual work; (3) There is no risk that the cooling fluid for quenching will enter the hole, and the aqueous solution of the water-soluble resin agent will flow through the hole wall. Since it is avoided that the aqueous solution adheres to the surface and forms a film by firing, the aqueous solution can be used with confidence, and rusting can be prevented without the conventional trouble of removing the film. The availability of active gases ensures protection against oxidation during heating of through holes or blind holes and small holes; The facets during the process can also be removed outside the opening, and (4) the combined effects of (1) to (5) above have a remarkable effect, such as automation of the hardening process of the shaft member. .

[Brief explanation of drawings]

FIG. 1 is a cross-sectional front view of the entire device according to one embodiment of the present invention, and FIG.
The figure is a partially sectional front view of another example device. H, Ha, Hb, Hc・---------
---Through hole or blind hole h・-----11--------・Small hole W・-1-
−−−−−−−−−−−−Shaft member s −−−−−−−−
-------- Circumferential groove 20 ---- One-way center shaft 22 --- Solid portion 23 ---- One --- Tubular portion 231 --- ----- Inside the tubular part of the center shaft on one side 24
−−−−−−−−−−−Through hole 30 on one side center shaft−・
-------------・Case 33-----1・----・Passage 4 G -------Uniaxial member support tube 41・-
−−1−−−−−−・Large inner diameter portion 42−−−−−−−
-----・Small inner diameter part 50---------One side center shaft 52---Cone-shaped shaft member 521---Cone-shaped tip part

Claims (1)

[Scope of Claims] 1) A shaft member having a through hole drilled from one end face to the other end face along the axis or a small hole branched from a blind hole drilled from one end face to a predetermined position on the circumferential surface. In the case of induction hardening the peripheral surface of the through hole, a gaseous fluid is caused to flow into the hole from one end surface of the through hole whose other end surface is closed or from the hole end surface of the blind hole, and the gaseous fluid is passed through the opening of the peripheral surface. 1. A method for surface hardening a shaft member having small holes in its circumferential surface, the method comprising heating with a heating coil and rapidly cooling with a hardening cooling fluid while ejecting water from the shaft. 2) Induction heating of the circumferential surface of a shaft member in which a small hole branching from a through hole drilled along the axis from one end face to the other end face or a blind hole drilled from one end face to a predetermined position opens on the circumferential surface. In a hardening device, a center shaft that holds and rotates the shaft member from both end surfaces with the tips thereof facing each other at a predetermined interval, one side has a solid portion in the direction of the base and a predetermined length from the tip surface. A shaft member with a predetermined outer diameter is formed in a hollow tubular part, and the center shaft is rotatable in a fixed case in which an annular circumferential groove is formed inside the outer periphery of the center shaft in the direction of the base. In addition to being covered in an airtight manner, a predetermined length of the tip portion includes a large inner diameter portion into which one end of the shaft member can be inserted, and the remaining portion is a hole position on the end surface of the shaft member into which the center shaft can be inserted. A two-stage inner diameter shaft member support tube with a small inner diameter portion is fixedly arranged so that the center shaft end surface is located within the small inner diameter portion, and the tip portion of the other side can be inserted into the center hole on the other end surface of the shaft member. The shaft member is formed into a cone shape, and a cylindrical closing member having an end surface that can come into contact with substantially the entire surface of the other end surface of the shaft member is fixedly arranged on the outer periphery excluding the cone-shaped tip, and the one center shaft is The inside of the tubular part and the circumferential groove of the case are communicated through a through hole, and a small hole is opened in the circumferential surface, and the circumferential groove is set so that a passage connecting to the gas supply source opens. Surface hardening equipment for shaft members.