JPH0114288B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel longitudinal striped surface hardening method and apparatus for forming a plurality of surface hardening stripes along the axial direction on the wall of a small diameter hole of a member.

Regardless of the size and shape of the member, parts in which the hole wall of a small diameter hole formed therein is a sliding wall are extremely frequently used. In order to improve the wear resistance of the hole walls of these members, surface hardening has been conventionally performed over the entire circumference of the hole walls using induction heating means. As shown in Figure 1a, the conventional method described above uses an induction heating coil C which is wound multiple times to have an outer diameter that separates a predetermined gap from the hole wall depending on the hole diameter of the hole H. After heating, for example, a cooling liquid is injected from the direction of the lower end face to form a surface hardening layer around the entire hole wall.

However, in conventional methods, when the member is a cylindrical member with no thickness in the hole wall, the entire circumferential wall is heated and rapidly quenched, resulting in a large number of unsuitable products deformed by quenching distortion. However, when the hole length or hole depth becomes large, the pattern of the magnetic lines of force φ generated from the heating coil C becomes as shown in Fig. 1b in so-called one-shot hardening.
As shown in Figure a, there is a tendency for a hardened layer to form as indicated by h, which is deep in the central part of the heating coil C in the longitudinal direction and gradually becomes shallower toward both ends, making it difficult to form a hardened layer with a uniform depth. Furthermore, a fatal drawback of the conventional method is that even if the R part of the deformed small-diameter hole H' shown in Fig. 1c is a sliding wall that requires wear resistance, the shape of the heating coil C is too large to be a multi-turn coil. Therefore, the entire circumferential wall must be heated, and a quenched hardened layer is formed not only in the R part but also in the parallel plane P part, so that the toughness that is lost due to the formation of the hardened layer is ensured. Therefore, an inconvenience may arise in which the wall thickness shown as S' must be used when the wall thickness S is originally sufficient. Furthermore, as can be seen from Figure 1a, since the reciprocating path of the conductor constituting the heating coil C must be accommodated within the inner diameter of the winding, the space for housing the coolant injection pipe within the inner diameter of the winding is extremely small. However, it is difficult to form an integral structure, and even if it were an integral structure, the reciprocating path conductor would get in the way, making it difficult to spray the cooling liquid uniformly over the entire circumference of the heating surface.

In order to solve the above-mentioned problems that exist in the conventional one-shot all-periphery wall surface hardening of the small diameter hole wall of a member using a multi-turn heating coil, the present inventor has developed a method in which a hardened layer is formed on a part of the sliding surface instead of the entire surface. The purpose of the present invention is to provide a method and apparatus for extremely easily surface hardening a hole wall in the form of vertical stripes, taking into account that wear resistance can be ensured if the hole wall is hardened.

The gist of the first invention of the present application is that (1) in the case where a plurality of surface hardened strips are formed along the axial direction on the wall of a small diameter hole of a member, (2) the surface hardened strips extend in the axial direction apart from the wall of the hole with a predetermined gap. (3) using a heating coil comprising a plurality of induction elements each having a pair of parallel conductors, (3) heating each wall strip simultaneously while concentrating magnetic lines of force on the wall strips facing each other; (4) A method for hardening the vertically striped surface of a small-diameter hole wall, in which the heated wall strip is cooled by a cooling liquid jetted from a cooling liquid jet pipe extending in the axial direction and arranged behind the induction element group.

Further, the second invention of the present application relates to a quenching apparatus for carrying out the above-mentioned first invention, and the gist thereof is (1) (a) providing a plurality of cutting parts in an annular conductive plate material to generate electricity. (b) each of the lead substrates in the vicinity of the other cut portions, excluding the cut portion between the portion portions where any of the adjacent lead substrates are connected to an induction heating power source; A heating coil consisting of a U-shaped inductive element group that stands up from the surface at right angles and extends for a predetermined length, adjacent ones connected at their tips, each having a pair of parallel conductors; 2) a coolant injection pipe passing through the annular hole of the lead board and parallel to the induction element group; (3) a magnetic material fitted to each of the parallel conductors; There is a vertical striped surface hardening device for a small-diameter hole wall, which is set to face a predetermined hardened strip on the hole wall with a predetermined distance apart.

A case in which the present invention is applied to a small diameter hole as shown in FIG. 1c, for example, will be explained with reference to FIGS. 2a to 2c. FIG. 2a is a perspective view of the device of the present invention, showing 1
The lead board shown as is an abbreviation for the annular conductive plate material.
Fragment 1a having an arc of 180° and each segment having an arc of 180°
It is divided into three pieces 1b and 1c each having an arc of 90°, and formed into an annular shape with electrical insulating materials 2a, 2b and 2c interposed therebetween. Lead portions 11b and 1 protruding in the circumferential direction are provided at end surfaces of the segmented pieces 1b and 1c that face each other via the electrical insulating material 2b.
1c is provided and connected to the high frequency power source E. The vicinity of the ends of the segmented segments 1b and 1c facing the segmented segment 1a through the electrical insulating materials 2a and 2c, respectively, and the segmented segments 1b and 1 of the segmented segment 1a.
Conductors 3b, 3c, 3 that stand up at right angles and extend a predetermined length on the respective surfaces near the ends opposite to c.
a ₂ and 3a ₁ are fixed, respectively, and conductors 3a ₂ and 3b, which are parallel to each other across the cut portions of the lead board 1 through the electrical insulating materials 2a and 2c, are connected at a connecting portion 31, and conductors 3a ₁ and 3c is connected at a connecting portion 32 at its tips to form U-shaped induction elements 301 and 302. Therefore, as shown in FIG.
- Conductor 3a ₂ - Segment 1a - Conductor 3a ₁ - Connecting portion 32
It flows through a circuit consisting of - conductor 3c, segment 1c, and lead portion 11c. Furthermore, 411 and 41
2 is a water supply pipe and a drain pipe for passing self-cooling water to the induction element 301 made of a pipe material, and 421 and 422 are respectively for passing self-cooling water to the induction element 302 made of the same material. The dimensions are set such that the outer surface of each of the conductors 3, which are constituent elements of the induction elements 301 and 302, faces a predetermined wall strip of the sliding wall R surface of the small diameter hole of the member W with a predetermined gap therebetween. At the same time, a magnetic body having a U-shaped end face, for example, a core 5, is fitted over a predetermined length on the inner surface opposite to the predetermined wall strip. Reference numeral 6 denotes a coolant injection pipe, whose upper end face is closed, and a coolant supply pipe 61 is connected to the lower end face, which passes through the ring hole 10 of the lead board 1 and extends through 301,
302, and extends a predetermined length in the axial direction. A large number of coolant injection holes 62 are provided in a predetermined portion of the pipe wall of the coolant injection pipe 6.
are provided with holes so that the cooling liquid can be injected in the direction of the wall stripes facing each of the conductors 3. A piece 7 made of an insulating material is fixed on the lead board 1, and is used as a stopper or positioning member when inserting the guide element group 30 into the small diameter hole H of the member W.

Using the above device, the sliding wall R of the small diameter hole H of the member W is
A case in which surface hardening is applied to a surface in the form of a plurality of vertical stripes will be explained.

Either the member W or the device is moved, and the inductive element group 30 of the device is inserted into the small diameter hole H, and each conductor 3 is
are opposed to a predetermined wall strip to be hardened with a predetermined gap between them. Next, when the high-frequency power source E is turned on, the high-frequency current flows through a circuit as shown in FIG. is concentrated on the opposing wall surface across a predetermined gap, and only the wall surface portion shown as h in FIG. 2b is heated in the form of vertical stripes along the axial direction. After a predetermined period of time has elapsed, the power supply E is turned off, and a coolant supply source (not shown) is driven to supply the coolant to the coolant injection pipe 6 through the coolant supply pipe 61 and injected from the injection hole 62. The wall strip that has been heated to a predetermined temperature is rapidly cooled down. After a predetermined period of time has elapsed, the injection of the coolant is stopped, and the device is removed from the small diameter hole H to complete the quenching.

The lines of magnetic force φ generated from each conductor 3 by the energization in the above-mentioned hardening are in the axial circumferential direction as shown by the arrows in FIG. 3. Therefore, when using the multi-turn heating coil shown in FIG. The quenching depth near the opening end will not become shallow due to the escape of the lines of magnetic force φ at the opening end, and even if the hole wall is relatively long in the axial direction, the quenching depth will be reduced to the wall striations over the entire length. uniformity of color is guaranteed. If it is desired to leave a non-hardened layer on the edge of the opening, it is preferable to use a shield plate S made of a metal material.

Thus, on each sliding wall R surface of the small-diameter hole H of the member W, there are two vertically striped surface-hardened stripes that are spaced apart from each other by a predetermined interval and parallel to the axial direction, and that have a uniform depth and the same width in the axial direction. Formed in one shot.

In the above embodiment, the core 5 is fitted to each conductor 3, but if the core 5 is not used,
The hole wall is an end surface (flat) called a hairpin type.
Similar to heating, for example, as shown in Fig. 4, a heating pattern h' is formed in which the wall striations facing each of the pair of parallel conductors 3, 3 are continuous, and the same power source and heating time provide sufficient hardness. However, if the heating conditions are changed to form a hardened layer with the required hardness, the same hardening distortion as in the conventional method will occur. This has been confirmed by other experiments conducted by Dr.

Figures 5a and 5b show a second embodiment of the invention. In this embodiment, the member W ₁ is a thin cylindrical body, and for example, eight longitudinal striped hardened strips are formed on the peripheral wall of the cylindrical body W ₁ over the entire circumference of the small-diameter inner hole wall. The high frequency current circuit of this embodiment is shown in FIG. 5a. In this case, the number of conductors 3 corresponding to the number of hardened strips is eight, so
A lead board 1 in which conductive plates made of five pieces each having a circular outer circumference and a rectangular inner circumference are arranged in a ring shape with an electrical insulating material 2 interposed therebetween, and an electrical insulating material 2 in the lead board 1. A heating coil is constituted by four induction elements 30 extending across each of the four divided parts, excluding the divided part connected to the high frequency power source E among the five divided parts 2. Behind the inductive element group 30 is the ring hole 1 of the lead board 1.
A coolant injection pipe 6 is arranged to extend in the axial direction through the cooling liquid injection pipe 6, and the core 5 is fitted with the coolant from a coolant injection hole 62 formed in a predetermined side surface of the coolant injection pipe 6. The specifications are set so that each of the conductors 3 can inject in the direction of the opposing hole wall stripes. The hardening operation is exactly the same as that in the first embodiment, so a description thereof will be omitted, but it is possible to form eight hardening stripes on the hole wall as shown at h in FIG. 5b. In this case, if the cylindrical body _W1 is thin and it is desired to leave a non-hardened layer between it and the outer periphery, the purpose can be achieved by jetting the cooling liquid from the outer periphery direction during heating.

In the first and second embodiments described above, the case where the heating coil and the coolant injection pipe are integrated has been described. It is configured to be relatively movable, for example, during heating, both the heating coil and the cooling liquid injection pipe are in the hole of the member W, and during cooling, only the heating coil moves, escapes from the hole, and remains inside the hole. The heating wall strip may be cooled by jetting the cooling liquid from the cooling liquid injection pipe 6.
Also, during heating, only the heating coil is inserted into the hole,
After the heating is completed, it may escape from the hole, and the coolant injection pipe 6 may be replaced and enter the hole to cool the heated wall strip. The heating coil and coolant injection pipe 6
The relative movement structure with the cooling liquid injection pipe 6 solves the difficulty of forming the shape of the coolant injection pipe 6 with an integral structure when the number of vertical striped walls increases. The same cooling effect as in the above embodiment can be obtained by injecting the cooling liquid all around the hole wall by using a cooling liquid injection pipe 6' having a circular end face as shown in FIG.

Note that the lead substrate is not limited to an annular shape, but any annular shape corresponding to the hole shape is sufficient.

The present invention has a structure in which the small diameter hole H has both ends open, or one end is open and the other end is closed.
Further, the present invention is applicable even if the hole wall is an inner wall of a cylindrical body having a U-shaped cross section. For example, if a cylinder with a U-shaped cross section is the member to be processed, the electrical insulating material 2 is sandwiched between 3,
The connecting part connecting between 3 and 3 is shown in Figure 2 a.
If it is close to the cylindrical wall or closed end wall as shown in Figure 2, there may be concerns about heat generation in the vicinity of the bottom of the hole due to the influence of magnetic lines of force generated from the connection, but as shown in Figure 7. As shown, in the case of the cylindrical body _W2 which is open on one side and closed on the other side, the wall thickness of the closed end surface is larger than the wall thickness in the circumferential direction, and the core 5 is not fitted in the connecting part. Therefore, the lines of magnetic force are diffused, so that the opposing wall portion near the connecting portion does not experience a high temperature rise. If you really want to avoid heat generation in that part, you can install the connecting part on the opposite side of the opposite wall of the conductors 3, 3, as shown at 33 in FIG. There is almost no influence from magnetic lines of force on the magnetic field, and no heat generation phenomenon occurs.

By carrying out the present invention, (1) a desired number of longitudinal hardened stripes can be formed in a single shot in a small diameter hole with both end faces open, or in a small diameter hole with one end face open and the other end closed; (2) Moreover, regardless of the size or shape of the part, and even if the small diameter hole has a circular, elliptical or other deformed cross section, it is possible to harden the hole wall of almost any shape in the form of vertical stripes. (3) Moreover, even if the length of the hardened strip is relatively long, the hardened strip can be formed with a substantially uniform depth and a clear width over the entire length; By forming the minimum number of hardened striations on the wall, the necessary wear resistance of the wall surface is guaranteed and the occurrence of hardening distortion in the member is prevented (5) Furthermore, it is possible to provide a sufficiently large coolant injection pipe. Extremely remarkable effects such as effective cooling can be obtained due to the heat, and its range of applications is wide.

[Brief explanation of drawings]

FIG. 1a is a cross-sectional front view for explaining the conventional small diameter hole hardening method, FIG. 1b is a front view showing lines of magnetic force generated from the conventional heating coil used in FIG. 1a,
FIG. 1c is a cross-sectional plan view of a member for explaining the drawbacks of hardening small diameter hole walls by the conventional method, FIG. Figure 2b is a plan view showing the hardening device shown in Figure 1a inserted into the small diameter hole;
Figure c is a perspective view showing the current circuit flowing through the heating coil of the hardening device shown in Figure 2a, and Figure 3 is a partial cross section for explaining the effect of the magnetic lines of force generated from the conductor on the hole wall in the device of the present invention. 4 is a front view, FIG. 4 is a plan view for explaining the disadvantages of not fitting the core to the conductor, FIG. 5a is a perspective view showing the current circuit in the second embodiment of the device of the present invention, and FIG. 5b is the fifth
FIG. 6 is a perspective view showing another embodiment of the coolant injection pipe used in the device of the present invention; FIG.
The figure is a sectional front view showing an example of forming longitudinal striped hardened stripes on the inner wall of a cylinder whose one end face is closed. 1... Lead board, 1a, 1b, 1c... segment, 10... ring hole, 2, 2a, 2b, 2c... division part; electrical insulating material, 3, 3a ₁ , 3a ₂ , 3b, 3c
...Conductor, 30...Inductive element group, 301, 302
...Induction element, 5...Magnetic material, 6...Cooling liquid injection pipe, W, _W1 , _W2 ...Member, H...Small diameter hole, E...
...High frequency power supply.

Claims (1)

[Scope of Claims] 1. In the case of forming a plurality of surface hardened strips axially aligned on the wall of a small diameter hole of a member, a pair of parallel portion conductors extending in the axial direction apart from the hole wall with a predetermined gap; Using a heating coil equipped with a plurality of inductive elements with 1. A method for hardening the surface of a small-diameter hole wall in the form of vertical stripes, characterized in that the heated wall strip is cooled by a cooling liquid jetted from a cooling liquid injection pipe extending in the direction. 2. A lead board that forms a plurality of surface-hardened strips along the axial direction on the wall of a small-diameter hole of a member, and a lead board that is made up of electrically opened fragments obtained by providing a plurality of cut parts in an annular conductive plate material, and the lead board. Excluding the cut section between the section sections where any of the adjacent sections are connected to an induction heating power source, the sections stand up at right angles from the surface of each section section near the other cut section and extend for a predetermined length, and the sections adjacent to each other are connected to each other. and a U-shaped induction element group connected at their tips and each having a pair of parallel conductors; and a cooling liquid injection pipe that passes through the ring hole of the lead board and runs parallel to the induction element group. A magnetic material is fitted into each of the parallel conductors, and each of the parallel conductors is set to face a predetermined distance from a predetermined quenched strip of the hole wall. Vertical striped surface hardening equipment for small diameter hole walls. 3. The vertical striped surface hardening device for a small diameter hole wall according to claim 2, wherein the lead substrate and the coolant injection pipe are formed into an integral fixed structure. 4. A vertically striped surface hardening device for a small diameter hole wall according to claim 2, wherein the coolant injection pipe is configured to be relatively movable within the annular hole of the lead substrate.