JPH0511028Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a metal surface hardening device, and more specifically, it injects plasma gas from a nozzle tip onto a workpiece to melt the surface of the workpiece, and injects powder into the molten part. When supplying a high hardness metal to form a hardened layer with excellent wear resistance on a predetermined portion of the workpiece, a first pipe made of metal that conveys the high hardness metal and the high hardness metal are melted. The present invention relates to a metal surface hardening device configured to be able to integrally and firmly hold a second pipe body made of ceramics which is led out into a pipe holder via separate holder members.

[Background of the invention] Camshafts, rocker arms, etc. installed in automobiles must be used continuously for long periods of time, and therefore, it is particularly desirable that their sliding parts have extremely excellent wear resistance. For this reason, various processing treatments have been conventionally applied to the camshaft, rocker arm, etc. in order to form a sliding contact portion with high hardness and excellent wear resistance.

For example, when casting and molding such camshafts, rocker arms, etc., a chiller is placed in the sliding contact area, and the supplied molten metal is rapidly cooled by the chiller to form a hardened chill layer. There is a way to do it. However, this cold metal does not provide sufficient hardness to the sliding contact portion, resulting in the inconvenience that products such as camshafts, rocker arms, etc. cannot be used for a long period of time.

Furthermore, a method has been devised in which a high hardness metal such as Cr or Mo is added to the molten metal and a chilled metal is used to form a high hardness chill layer at the portion that will become the sliding contact part. However, in order to form a chill layer having a desired hardness using this type of Cr, Mo, etc., it is necessary to add a certain amount or more of the high hardness metal to the molten metal. Moreover, during the hardening process, a considerable amount of this high-hardness metal gets mixed into parts other than the sliding contact parts.
Therefore, the workpiece taken out after casting has a high hardness as a whole, and it has been pointed out that there is a drawback that cutting is difficult when performing finishing machining or the like on the molded workpiece.

Therefore, in order to eliminate the above-mentioned drawbacks, the applicant has
A nozzle chip that has an electrode inside and ejects plasma gas, a shield cap that surrounds the nozzle chip, a metal introduction pipe that supplies high-hardness metal powder or granules toward the plasma gas, and the nozzle chip and shield cap. A metal surface hardening apparatus has been proposed in which a shielding member is provided between the nozzle tip and a shielding member that is spaced from the nozzle tip and covers the tip of the nozzle tip (Japanese Patent Laid-Open No. 62-33785).

As a result, when plasma gas is injected onto the workpiece, the plasma gas does not diffuse through the shielding gas, melting a predetermined part of the workpiece well, and giving the workpiece high hardness with excellent wear resistance. It is possible to form a hardened layer, and furthermore, it is possible to obtain the effect that the shielding member can prevent high hardness metal from adhering to the nozzle tip.

By the way, since the metal introduction tube enters the shield cap and is exposed to high temperature heat generated by plasma gas, the metal introduction tube is made of a ceramic material. It is proposed that. This is because ceramics have excellent heat resistance and do not generate arcs themselves.

In this case, ceramics are relatively expensive, and the tip of the metal introduction tube that enters the shield cap is made of ceramic material, and the other parts, i.e., the metal source, are used for the device. Metal materials such as stainless steel are used for the metal conveyance path leading to. Therefore, it is necessary to bond the first tube made of ceramics and the second tube made of metal, and a heat-resistant adhesive is usually used.

However, this type of adhesive has poor durability and cannot maintain the bond between the ceramics and the metal for a long period of time. Moreover, in order to prevent the metal from adhering to the inner wall of the metal introduction tube, the metal introduction tube itself is vibrated by an ultrasonic vibration device. This causes vibrations at the joint between the ceramics and the metal, which causes the joint to separate in a short period of time.

[Purpose of the invention] The present invention has been made to overcome the above-mentioned disadvantages, and includes a first tube body made of ceramics for supplying high-hardness metal to the plasma gas injected from the nozzle tip, and the high-temperature tube body. A second tube body made of metal for conveying hard metal is configured to be integrally engaged with the pipe holder via separate holder members, whereby the first tube body made of a different material, respectively And since the second pipe bodies are not directly joined to each other, the first and second pipe bodies can be firmly held in the pipe holder without being affected by external vibrations, etc., and can be continuously used for a long period of time. The object of the present invention is to provide a metal surface hardening device that can be used as a metal surface hardening device.

[Means for Achieving the Object] In order to achieve the above-mentioned object, the present invention generates a plasma arc between an electrode and a workpiece to melt the surface portion of the workpiece, and also introduces a plasma arc into the molten surface portion. A metal surface hardening device that supplies high-hardness metal powder from a pipe to form a hardened layer, and a pipe holder that is attached to a shield cap for supplying shield gas to the plasma arc;
a first holder member that fits into a pipe holder by engaging a first pipe made of ceramics that forms the introduction pipe and guides the powder to the melting surface; a second holder member that is externally fitted onto a second metal pipe body that conveys particles and is screwed into the pipe holder; and the second holder member that is interposed between the first and second holder members. and a locking member that presses and holds the outer circumferential portion of the second tube under the spiral action of.

In addition, the present invention has a slotted structure in which the end of the first holder member is provided with a hole into which the first tube fits, and the end is press-deformed in advance and the first tube is press-fitted into the end. It is characterized by

[Embodiments] Next, preferred embodiments of the metal surface hardening device according to the present invention will be described in detail with reference to the accompanying drawings.

In FIGS. 1 and 2, reference numeral 10 indicates a metal surface hardening device according to this embodiment. A main body 12 that constitutes the device 10 and is surrounded by an outer cylinder member 11 has a substantially cylindrical shape, and a screw hole 14 is formed in the inner peripheral surface of the main body 12 . Then, an electrode 16 is disposed within the main body 12, and a threaded portion 20 formed at one end of the nozzle tip 18 is screwed into the screw hole 14. In this case, a substantially conical tip 22 is provided at the other end of the nozzle tip 18, a hole 24 is formed in the center of the nozzle tip 18 through which the electrode 16 is inserted, and an outlet of the hole 24 is formed. A plasma gas deriving nozzle portion 26 having a smaller diameter is formed in communication with the side via a step portion. An opening 28 is defined between the outer periphery of the nozzle tip 18 and the inner periphery of the main body 12, and cooling water is supplied to the opening 28. In addition, nozzle tip 18
A sealing O-ring 30 is interposed at the joint portion between the main body portion 12 and the main body portion 12 .

Furthermore, a circumferential groove 32 is cut into the tip end 22 of the nozzle tip 18, and a shielding member 36 is attached to the nozzle tip 18 via a ring member 34 that fits into the circumferential groove 32. That is, the shielding member 3
6 is made of an insulator, for example, a ceramic material, and its shape corresponds to the tip 22 of the nozzle tip 18, with openings 38 and 40 defined in its upper and lower parts, respectively. Locking parts 42a to 42d, which are formed on the upper part of the shielding member 36 and have a predetermined width and bulge radially inward, face near the inner end of the rotating opening 38, and these locking parts 4
A ring member 34 is engaged with the lower ends of the shielding members 2a to 42d to attach the shielding member 36 to the nozzle tip 18. Therefore, a plurality of passages 44 can be defined between the outer peripheral wall of the nozzle tip 18 and the inner peripheral wall of the shielding member 36 by the locking parts 42a to 42d that bulge into the interior of the shielding member 36. It will be easily understood.

Next, the flow rate adjustment member 46 is attached to the end of the shielding member 36 on the opening 38 side. The flow rate adjusting member 46 has a substantially ring shape, and a hole 48 is formed at one end thereof into which the end of the shielding member 36 is fitted to a predetermined depth. A first fluid inlet 50 having a predetermined gap is defined between the inner circumferential surface of the flow rate adjusting member 46 and the outer circumferential surface of the main body portion 12, and a first fluid inlet 50 is formed between the inner circumferential surface of the flow rate adjusting member 46 and the shield cap. A second fluid introduction port 54 having a predetermined gap is defined between the second fluid introduction port 54 and the inner circumferential surface of the second fluid introduction port 52 .

The shield cap 52 has a hollow shape and has a stepped portion 55 formed on its outer periphery, and holes 56a and 56b are formed therein at a predetermined angle, for example, 45°, with respect to the horizontal direction. In this case, a threaded portion 58 is provided at the end of the shield cap 52, and a nut member 59 is screwed into the threaded portion 58.
The shield cap 52 is attached to the main body portion 12 through. Therefore, a passage 60 is defined in the shield cap 52 that communicates with a shield gas passage (not shown) of the main body 12, and this passage 60 communicates with the passage 44 via the first fluid introduction port 50, The second fluid inlet 54 communicates with a passage 61 defined between the shield cap 52 and the shield member 36 .

Then, the pipe holder 62 is attached to the shield cap 52. A hole 64 into which the outer periphery of the shield cap 52 fits is formed in the center of the pipe holder 62, and a slit-shaped opening 66 opening the hole 64 to the outside is formed at the end of the pipe holder 62. defined. A screw hole 68 and a hole 70 coaxially communicate with each other at both ends of the opening 66, and the end of a bolt (not shown) inserted through the hole 70 is screwed into the screw hole 68. As a result, the diameter of the hole 64 is reduced, and the outer periphery of the shield cap 52 is held between the pipe holder 62.
Thereby, the pipe holder 62 can be fixed to the shield cap 52 while being engaged with the stepped portion 55.

At both ends of the pipe holder 62 in the diametrical direction, bulges 71a and 71b are formed to protrude outward, respectively. The stepped holes 72a, 72b and the screw holes 74a, 74b are coaxially formed with the holes 56a, 56b of the shield cap 52.

First holder members 76a, 76b fit into the stepped holes 72a, 72b. The first holder member 76a is substantially made of stainless steel, and its outer peripheral portion has a shape corresponding to the stepped hole portion 72a. In the center of the first holder member 76a, a hole 78 into which a stainless steel pipe (to be described later) is fitted is bored from the large diameter end side to a predetermined depth, and a tapered hole 79 communicates with the hole 78. On the other hand, a hole 80 is similarly provided from the small diameter end side of the first holder member 76a to a predetermined depth, and this hole 80 has a slit 82 formed on the outer circumference of the first holder member 76a. communicate (see Figure 3).
That is, the small diameter end portion of the first holder member 76a employs a slotted structure. A high-hardness metal powder introduction pipe is configured in the hole 80 of the first holder member 76a, and the first holder member 76a is made of a ceramic material.
One end of the tube body 84a is fitted. Note that the first holder member 76b is the first holder member 76a described above.
The configuration is similar to that, and detailed explanation thereof will be omitted.

Next, a second tubular body 86a made of a stainless steel pipe is connected at one end to a high hardness metal powder supply source (not shown) in the hole 78 of the first holder member 76a.
The other end is fitted, and the locking member 88a is fitted onto the second tube 86a. That is, the locking member 88a is made of a metal material that is easily deformable, for example, a copper material, and both ends of its outer periphery have a substantially cylindrical shape that is inclined inward in the radial direction. Then, one end of the locking member 88a is attached to the first holder member 7.
6a, while the other end is engaged with the second holder member 90a.

The second holder member 90a has a substantially cylindrical shape,
A threaded portion 92a that is screwed into the threaded hole 74a of the pipe holder 62 is formed on its outer peripheral portion. A tapered hole 94a is provided in the center of the second holder member 90a at the end on the first holder member 76a side.
The other end of the locking member 88a is fitted into the locking member 88a.

Note that the first holder member 76b is attached to the bulged portion 71b.
The first tubular body 84b is held through the first tubular body 84b, and the second tubular body 86b is secured by a locking member and a second holder member 90b (not shown). At that time, the first
The ends of the holder members 76a, 76b fit into holes 56a, 56b formed in the shield cap 52, and the ends of the first tubes 84a, 84b fit into the shielding member 36.
and the shield cap 52.
1 for a predetermined length and the first tube body 84a,
The extension line of 84b and the extension line of nozzle part 26 intersect at the bottom.

The metal surface hardening device according to the present invention is basically constructed as described above, and its operation and effects will be explained next.

First, the device 10 is positioned near a portion of the workpiece W that will be the sliding contact portion, and then the electrode 16 is connected to the negative side of a DC power source (not shown), while the workpiece W is connected to the positive side. Further, a working gas such as argon gas is supplied to the hole 24, and the passage 60
supply shielding gas. For this reason, the electrode 16
An arc is generated between the and the workpiece W, and the plasma gas is squeezed through the nozzle part 26 and flows from the tip part 22 to the shielding member 3 as a high-temperature, high-speed plasma arc.
It is led out to the outside through the opening 40 of No. 6.

In this case, as shown in FIG.
The liquid enters the passage 44 of the shielding member 36 through the first fluid inlet 50 of the plasma arc and is blown onto the led-out plasma arc. Therefore, the diameter of the plasma arc can be further reduced by the convergence effect of the gas flow and the thermal pinch effect caused by cooling due to the shielding gas supplied from the circumferential direction, and a high temperature is applied to a desired part of the workpiece W. ,
It becomes possible to inject a high-speed plasma arc to effectively melt it and form a molten pool 100 (see FIG. 4).

On the other hand, a high hardness metal 102 is supplied to the second tube bodies 86a, 86b from a high hardness metal supply source (not shown), and the high hardness metal 102 is supplied to the second tube bodies 84a, 84b.
into the plasma arc. In this case, the high hardness metal 102 includes Cr, Mo, Ni,
It is possible to select various materials such as W, V, Nb, etc. alone, alloys of these metals with each other or with other metals, and compounds with carbon or the like. Also,
At that time, the high hardness metal 102 may be used alone or in combination.
Supplied in combination with more than one species.

The high hardness metal 102 supplied into the plasma arc from the respective first tube bodies 84a and 84b is heated by the plasma arc and forms a molten pool 100 at high speed.
mixed in. Here, the ejection pressure of the plasma arc acts on the high hardness metal 102, and the movement of the device 10 is controlled to displace above the work W in a predetermined direction.
2 is stirred and uniformly dispersed within the molten pool 100. At this time, if the high-hardness metal 102 is easily melted, it will be melted in the molten pool 100, whereas if it is difficult to melt, it will be dispersed in the molten pool 100.

In this manner, after the device 10 is displaced to form the molten pool 100 at a predetermined portion of the workpiece W, the power supply to the electrode 16 and the workpiece W is stopped. Next, by cooling the workpiece W for a predetermined period of time, a hardened layer in which the high hardness metal 102 is uniformly dispersed or mixed is formed on a desired surface layer portion of the workpiece W.

In this case, according to this embodiment, the first and second holder members 76a, 90a and the locking member 88a can be connected without directly joining the first tube 84a and the second tube 86a, which are made of different materials, with an adhesive. It can be firmly held to the pipe holder 62 via.

That is, as described above, the first holder member 7
A hole 80 for fitting the first tube 84a is formed in the end of the shield cap 52 that fits into the hole 56a of the shield cap 52, and a slit 82 communicates with the hole 80 so as to allow the sliding. It uses a split structure. Therefore, first, the end of the first holder member 76a is pressed to deform the hole 80 into an elliptical shape through the slit 82 in advance. And the hole 80
When one end of the first tube 84a is press-fitted into the first tube 84, the hole 80, which has been deformed into an elliptical shape, will fit into the first tube 84.
The first hole 80 is expanded by a and forms the hole 80.
The end of the holder member 76a allows the first tube body 84 to be
A can be firmly held.

The first holder member 76a holding the first pipe body 84a in this way is inserted into the stepped hole 72 of the pipe holder 62.
a, and one end of the locking member 88a is fitted into the tapered hole 79 of the first holder member 76a.
Furthermore, the second
The second tube 86a is integrally fitted into the holder member 90a, the locking member 88a, and the hole 78 of the first holder member 76a. Next, when the second holder member 90a is screwed and the threaded portion 92a formed on the second holder member 90a is screwed into the screw hole 74a of the pipe holder 62, the end of the second holder member 90a The locking member 8 is inserted into the tapered hole 94a formed in the
The other end of 8a is fitted.

In this case, both ends of the locking member 88a are directed outward and inclined radially inward, and if the second holder member 90a is further screwed in this state,
A pressing force is applied to both ends of the locking member 88a in the direction of the arrow in FIG. 5 by the respective ends of the first holder member 76a and the second holder member 90a. At this time, since the locking member 88a is made of a relatively easily deformable material, for example, copper, the locking member 88a is deformed radially inward due to the pressing force in the direction of the arrow, and the second This results in firmly holding the outer circumferential portion of the tube body 86a.

As a result, the first tube 84a and the second tube 86a are firmly held by the pipe holder 62. As a result, unlike the conventional method in which the first tube 84a made of a ceramic material and the second tube 86a made of a stainless steel pipe are directly bonded with adhesive, the first tube 84a is
a and the second tubular body 86a are never separated. Therefore, for example, even when a predetermined vibration is applied to the second tube 86a via an ultrasonic vibration device (not shown), the first tube 84a and the second tube 86a are not affected by the vibration. It is possible to firmly hold the pipe holder 62 against the pipe holder 62. After all, the apparatus 10 can be used continuously for a long period of time, and has the advantage of being able to carry out extremely efficient surface treatment processes.

[Effects of the invention] As described above, according to the invention, the first tube made of ceramics supplies a high hardness metal into the plasma arc generated between the electrode and the workpiece, and the first pipe body that conveys the high hardness metal. and a second metal pipe body, which are integrally held with respect to the pipe holder via separate holder members. In this way, since the first tube body and the second tube body, which are made of different materials, are not directly joined with adhesive or the like, it is possible to prevent the first tube body and the second tube body from separating. I can do it. Therefore, it is possible to firmly hold the first and second pipe bodies against the pipe holder without being affected by external vibrations, etc., and the device can be used continuously for a long period of time. Effects can be obtained. This brings to light the advantage that the efficiency of surface hardening work can be easily achieved.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments, and various improvements and design changes can be made without departing from the gist of the present invention. Of course.

[Brief explanation of the drawing]

Fig. 1 is a partially omitted exploded perspective view of a metal surface hardening device according to the present invention, Fig. 2 is a partially omitted longitudinal sectional view of the device, and Fig. 3 is a partially omitted exploded view of the introduction pipe that constitutes the device. A perspective view, FIG. 4 is a partially omitted explanatory view showing the usage state of the device, and FIG. 5 is an explanatory view of the assembling work of the introduction pipe shown in FIG. 3. 10... Metal surface hardening device, 12... Main body part,
18... Nozzle tip, 36... Shielding member, 46
...Flow rate adjustment member, 52...Shield cap,
62...Pipe holder, 76a, 76b...Holder member, 84a, 84b, 86a, 86b...Pipe body, 88a, 88b...Locking member, 90a, 90
b...Holder member.

Claims (1)

[Claims for Utility Model Registration] (1) Generating a plasma arc between an electrode and a workpiece to melt the surface of the workpiece,
A metal surface hardening device for forming a hardened layer by supplying high-hardness metal powder from an introduction pipe to the molten surface, the pipe being attached to a shield cap for supplying shield gas to the plasma arc. a holder; a first holder member that fits into the pipe holder by engaging a first pipe made of ceramics that constitutes the introduction pipe and guides the granular material to the melting surface; a second holder member which is fitted externally to a second pipe made of metal and which conveys powder and granular material and is screwed into the pipe holder; and a second holder member which is interposed between the first and second holder members and 2. Under the spiral action of the holder member, the second
A metal surface hardening device comprising: a locking member that presses and holds an outer peripheral portion of a tube body. (2) In the device according to claim 1, the end of the first holder member has a slotted structure with a hole into which the first tube is fitted, and the end is pressed and deformed in advance to form a slotted structure. A metal surface hardening device characterized in that a first pipe body is press-fitted.