JPH10296474A - Powder material injection nozzle and method for preventing vibration of the nozzle - Google Patents

Abstract

(57) [Problem] To stabilize the pouring position of a powder material by preventing vibration of a powder material pouring nozzle for pouring a powder material into a metal base material. SOLUTION: When forming a piston ring groove of an aluminum alloy engine piston, in order to improve abrasion resistance and durability, a build-up layer of a copper alloy powder material is formed by laser beam irradiation, Groove processing is performed on this buildup layer. At the time of laser beam irradiation, a powder material is charged into the groove from the powder material charging nozzle 17, and the powder material is melted to form a build-up layer. The powder material input nozzle 17 includes a nozzle body 19 and a powder nozzle port 21 for discharging the powder material.
And a gas nozzle port 23 for discharging an assist gas for blowing off plasma generated during laser beam irradiation. The base end of the powder nozzle port 21 is fixed to the end face 19a of the nozzle body 19, and is fixed to the gas nozzle port 23 by a support bracket 33 provided between the end face 19a and the mesh 31 for rectifying assist gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder material for feeding a powder material when a powder material made of another metal is melted on a surface of a metal base material by laser beam irradiation to form a build-up layer. The present invention relates to a charging nozzle and a method of preventing vibration of the nozzle.

[0002]

SUMMARY OF THE INVENTION It is an object of the present invention to stabilize the powder material charging position by preventing the vibration of the powder material charging nozzle even if vibration occurs in the movable part of the cladding apparatus main body. The purpose is.

[0003]

Means for Solving the Problems To achieve the above object, first, the present invention provides a method of forming a cladding layer by melting a powder material made of another metal on a surface of a metal base material by irradiating a laser beam. When forming, in a powder material charging nozzle for charging the powder material, a powder body is introduced from the outside and fixed to the cladding apparatus main body side, and one end is fixed to the nozzle body and the introduction is performed. An inner cylindrical portion provided with a powder discharge port for discharging the powder material from the other end side, and a plasma which covers the periphery of the base end side of the inner cylindrical portion, is introduced into the nozzle body, and is generated at the time of the laser beam irradiation. An outer cylinder part that sends out an assist gas for blowing off the air through a space formed between the inner cylinder part and the outside.
A support bracket for supporting the distal end of the inner cylindrical portion from the base end with the outer cylindrical portion is provided.

According to the above construction, the inner cylindrical portion having the powder discharge port at the distal end is fixed at the base end to the nozzle body, and the distal end side from the proximal end is supported by the outer cylindrical portion by the support bracket to provide a two-point support. Therefore, even if the vibration of the movable portion is transmitted to the nozzle body during the operation of the build-up device, the vibration of the inner cylindrical portion is prevented.

Secondly, a rectifying section for rectifying the flow of the assist gas is provided in a space between the inner cylindrical section and the outer cylindrical section,
The support bracket is provided on the base end side of the inner cylindrical portion with respect to the straightening portion.

[0006] According to the above configuration, since the support bracket is arranged upstream of the rectifying section, the assist gas rectified by the rectifying section does not disturb.

Third, in the support bracket, the ratio b / a of the distance a from the rectifying portion to the fixed portion of the inner cylinder portion to the nozzle body and the distance b from the rectifying portion to the support bracket is 1 /.
It is provided at a position where 4 <b / a <1/2.

If the ratio b / a is 1/4 or less, that is, if the support bracket is too close to the rectifying section, the rectifying action in the rectifying section is impaired, and the assist gas is disturbed. On the other hand, if b / a is 以上 or more, that is, if the support bracket is too close to the base end of the inner cylinder, it is fixed to the base body of the nozzle on the base end, which serves as two support portions for the inner cylinder. Since the distance between the portion and the support bracket is too close, the effect of preventing vibration on the inner cylindrical portion is impaired.

Therefore, the ratio b / a is set to 1/4 <b /
By setting a <1/2, the vibration of the inner cylindrical portion is prevented without causing disturbance of the assist gas.

Fourthly, the support bracket is disk-shaped, the outer peripheral surface of which is fixed to the inner peripheral surface of the outer cylindrical portion, and the inner peripheral surface of the through hole provided at the center is the outer peripheral surface of the inner cylindrical portion. And a plurality of assist gas passage holes in the circumferential direction.

According to the above configuration, the support bracket supports the entire circumference of the inner cylindrical portion in the circumferential direction while passing the assist gas, and the entire outer circumferential surface thereof is supported by the outer cylindrical portion. The effect of preventing vibration on the inner cylindrical portion is improved.

Fifth, when a powder material made of another metal is melted by laser beam irradiation on the surface of the metal base material to form a build-up layer, a powder material injection nozzle for feeding the powder material is used. In the vibration preventing method, an inner cylinder provided with a powder discharge port for externally introducing a powder material and having one end fixed to a nozzle body fixed to the cladding apparatus main body side and discharging the introduced powder material from the other end side. Part, which covers the periphery of the base end side of the inner cylindrical part, and an assist gas for blowing plasma generated at the time of laser beam irradiation introduced into the nozzle body is formed between the inner cylindrical part and the assist gas. Vibration is prevented by being supported by the outer cylindrical portion that is sent out through the space.

According to the above method, the inner cylindrical portion having the powder discharge port at the distal end is fixed at the base end to the nozzle body, and the distal end side from the base end is supported by the outer cylindrical portion by the support bracket to provide a two-point support. Therefore, even if the vibration of the movable portion is transmitted to the nozzle body during the operation of the build-up device, the vibration of the inner cylindrical portion is prevented.

[0014]

According to the first invention or the fifth invention,
The inner cylinder part with the powder discharge port at the tip is fixed at the base end to the nozzle body, and the tip side is supported by the outer cylinder part by the support bracket, so that it is supported at two points, so it can be moved when the build-up device is operating Even when the portion vibrates, the vibration of the inner cylindrical portion can be prevented, and the pouring position of the powder material discharged from the powder discharge port becomes stable, so that a high-quality overlay can be obtained.

According to the second invention, the support bracket is
Since it is arranged on the upstream side of the rectifying section, it does not cause disturbance of the assist gas rectified by the rectifying section, and prevents the generation of holes in the build-up layer due to the entrainment of the assist gas into the powder material. Can be.

According to the third invention, the support bracket is
The ratio b of the distance a from the rectifying portion to the fixed portion of the inner cylindrical portion to the nozzle body and the distance b from the rectifying portion to the support bracket.
Since / a is provided at a position where 1/4 <b / a <1/2, the support bracket is located at a predetermined distance from the rectifying section, and the rectifying action in the rectifying section is effectively exhibited, and assist is provided. The gas turbulence can be reliably prevented, and the fixed portion to the nozzle body and the support bracket, which are two support portions for the inner cylinder portion, are also separated from the support bracket by a predetermined distance, and the vibration of the inner cylinder portion is also reduced. It can be reliably prevented.

According to the fourth invention, the support bracket is
Since the entire circumference in the circumferential direction of the inner cylindrical portion is supported while the assist gas is passed, and the entire outer circumferential surface is supported by the outer cylindrical portion, the vibration suppressing effect can be improved.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall configuration diagram of a laser cladding apparatus having a powder material charging nozzle according to an embodiment of the present invention. The metal base material here is a piston 1 made of an aluminum alloy in an engine, and the piston 1 is formed in a ring groove 3 serving as a piston ring groove formed in advance by a powder material made of a copper alloy as another metal. A build-up layer is formed. The piston ring groove into which the piston ring is fitted is
It is formed by machining. Thereby, the wear resistance and durability of the piston ring groove in the piston lightened as an aluminum alloy are improved.

The piston 1 is held in a horizontal position by a jig 5, and the rotation of the jig 5
Rotate about the center axis T of The powder material 7 is injected into the annular groove 3 from obliquely above the annular groove 3, and a laser beam 9 for heating and melting the charged powder material 7 is irradiated from above the annular groove 3. You.
In FIG. 1, the charging direction of the powder material 7 is shown from the left side in the drawing along the center axis line T for simplicity, but is actually obliquely upward along the groove 3.

The laser beam 9 oscillated from a CO ₂ laser oscillator built in the cladding apparatus main body 11 is collected at a predetermined irradiation site via a condensing head 13 constituting a part of the cladding apparatus main body 11. Be lighted.

On the other hand, the powder material 7 is injected into the annular groove 3 by the powder material injection nozzle 17. As shown in FIG. 2 which is a sectional view showing the internal structure of the powder material charging nozzle 17 and FIG. 3 which is a right side view of FIG.
A powder nozzle port 21 serving as an inner cylindrical portion, one end of which is connected to a substantially central portion of a right end face 19a in the drawing of the nozzle main body 19, and covering the periphery of the base end side of the powder nozzle port 21; And a gas nozzle port 23 as an outer cylinder part having one end connected to the gas nozzle port 23.

The powder nozzle port 21 has a base end 21a which is screwed to the end face 19a of the nozzle body 19, and the base end 21a has a front end projecting outward from the other end of the gas nozzle opening 23. A distal end 21b having a powder discharge port is screwed to the end. This powder nozzle port 21
A powder introduction passage 25 into which a powder material is introduced from the outside is formed in the nozzle body 19 on the same straight line as the above. One end of the powder introduction passage 25 is open to the end face 19a and communicates with the powder nozzle port 21, and the other end is the left end face 19b in the drawing.
The opening 25a is formed in the opening 25a.
A powder material is introduced from a. A cooling water passage 27 is also formed in the nozzle body 19.

The gas nozzle port 23 sends out an assist gas for blowing off the plasma generated at the time of laser beam irradiation through the space 28 formed between the gas nozzle port 21 and the outside. 19
One end is screw-connected to the outer peripheral portion of a. Further, a gas introduction passage 29 for introducing the assist gas is formed in the nozzle body 19. One end of the gas introduction passage 29 is opened at the end face 19a as an opening 29a, and the other end is opened at a side surface (an upper part in the drawing).
And an assist gas is externally introduced into a space 28 between the powder nozzle port 21 and the gas nozzle port 23.

Almost half of the gas nozzle port 23 in the longitudinal direction (left-right direction in FIG. 2) has a stepped portion 2 having a large inner diameter.
Near the tip of the gas nozzle port 23 in the step 23a, a mesh 31 is provided as a rectifying section for rectifying the flow of the assist gas.
A disk-shaped support bracket 33 is provided at the left end in FIG. A cylindrical collar 35 is interposed in the step 23 a between the support bracket 33 and the mesh 31, and a mesh holder 37 is attached to the tip of the gas nozzle port 23 by screw connection.

As shown in FIG. 4, the support bracket 33 is provided with six assist gas passage holes 33a for allowing the assist gas to pass therethrough at equal circumferential intervals.
Through hole 33b into which powder nozzle port 21 is inserted at the center
Are formed. The inner peripheral surface of the through hole 33b of the support bracket 33 is fixed to the outer peripheral surface of the powder nozzle port 21, while the outer peripheral surface of the support bracket 33 is fixed to the inner peripheral surface of the step portion 23a. Thereby, the powder nozzle port 21
Is fixed to the nozzle main body 19 at the base end side, and is fixed to the gas nozzle port 23 via the support bracket 33 at the distal end side, and is supported at two points.

The mounting position of the support bracket 33 is a ratio b between a distance a from the mesh 31 to an end surface 19a which is a fixing portion of the powder nozzle port 21 to the nozzle body 19 and a distance b from the mesh 31 to the support bracket 33. / A is 1 /
4 <b / a <1/2.

The nozzle body 19 has two mounting holes 19c penetrating in a direction perpendicular to the plane of the paper of FIG. 2, and the mounting holes 19c are circular mounting holes provided on the side of the nozzle body 19. It penetrates the board 19d. On the other hand, a mounting bracket 38 is fixed to a side portion of the light-collecting head 13 on the side of the building-up device main body 11, and a screw (not shown) is inserted into the mounting hole 19 c and screwed into the mounting bracket 38. The powder material charging nozzle 17 is attached to the main body 11 side.

The powder material is supplied to the powder material supply nozzle 17 from a material supply section 39 having a material storage section for storing a powder material made of a copper alloy via a switching valve 41. The switching valve 41 is supported by the cladding device main body 11 by a support arm 42, and houses therein a valve main body that moves in the left-right direction in FIG. The movement of the valve body switches between a material supply mode in which the powder material fed from the material supply section 39 is supplied to the powder material input nozzle 17 and a material discharge mode in which the powder material is discharged to the discharge container 43.

The material supply section 39 includes a hollow disk-shaped case 45 that is a material storage section, and a material storage cylinder 47 that feeds powder material into the case 45 from an upper portion near the outer periphery of the case 45. And a gas supply port 49 for feeding helium gas into the case 25 from below the case 45. One end of a material supply pipe 51 is connected to an upper portion of the case 45 near the outer peripheral side at a position different from the material storage tube 47.

The case 45 houses a rotatable material receiver having an annular concave portion into which the powder material from the material storage tube 47 enters, and the powder material supplied to the material receiver is rotated by the rotation of the material receiver. When the helium gas sent into the case 45 reaches the connection portion of the material supply pipe 51, the helium gas is sequentially sent to the material supply hose 51 as the helium gas flows into the material supply pipe 51. The other end of the material supply pipe 51 is
Degassing hopper 53 installed above switching valve 43
It is connected to the. The degassing hopper 53 plays a role of releasing helium gas sent together with the powder material through the material supply pipe 51 to the outside.

Switching valve 43 and powder material injection nozzle 17
Is connected to each other by the relay section 55 and the material supply pipes 57 and 59 connected to both ends thereof, and is sent from the material supply section 39 to the switching valve 43 in a state where the switching valve 43 is switched to the material supply mode. The powder material is supplied to the material supply pipe 5
7, and is supplied to the powder material input nozzle 17 via the relay section 55 and the material supply pipe 59.

In the above-mentioned laser cladding apparatus, the powder material injection nozzle 17 is inserted into the groove 3 of the rotating piston 1.
And a laser beam 9 is applied to the charged powder material to form a build-up layer on the groove 3.

At this time, on the side of the cladding apparatus main body 11, in the movable object, for example, in the switching valve 43, vibration is generated by the movement of the accommodated valve main body, and this vibration is transmitted to the powder material charging nozzle 17. Will be.
However, since the powder material injection nozzle 17 has the powder nozzle port 21 fixed at the base end side to the nozzle body 19 and also fixed to the gas nozzle port 23 by the support bracket 33, it is a two-point support. The vibration of the powder nozzle port 21 is prevented, the position of the powder material discharged from the tip 21b into the groove 3 of the piston 1 is stable, and the shape of the build-up layer formed in the groove 3 is also stable. Becomes

When a buildup layer is formed on the entire circumference of the annular portion as in a piston ring groove, as shown in FIG.
It is necessary to form an overlap portion L where the end portion E is overlapped with the start end portion S serving as the build-up work start portion. In such a case, depending on the shape of the starting end portion S in the overlapped portion L, a problem such as a non-welded portion or a crack in the overlapped portion may occur, which is particularly effective.

In the powder material introduction nozzle 17, the powder material introduced through the powder introduction passage 25 is discharged from the powder nozzle opening 21, and at the same time, the assist gas introduced through the gas introduction passage 29 is supplied to the gas nozzle opening 23. It is discharged from. This assist gas is supplied to the support bracket 33.
After passing through the assist gas passage hole 33b, the mesh 3
The laser beam 9 is rectified by passing through the laser beam 1 and efficiently blows off the plasma generated when the powder material is melted by the laser beam irradiation, thereby preventing the laser beam 9 from absorbing the plasma and causing poor powder material melting.

Here, the ratio of the distance a between the mesh 31 and the end face 19a, which is a fixing portion of the powder nozzle port 21 to the nozzle body 19, and the length b from the mesh 31 to the support bracket 33 is as follows: b / a is
It is provided at a position where ４ <b / a <１ ／,
The distance between the end face 19a and the mesh 31 is at least a predetermined distance.

When the support bracket 33 is separated from the end face 19a by a predetermined distance or more, the vibration preventing effect by the two-point support is exhibited, and the vibration of the powder nozzle port 21 can be reliably prevented. On the other hand, since the support bracket 33 is separated from the mesh 31 by a predetermined distance or more, the rectifying action of the mesh 31 is effectively performed, and the disturbance of the assist gas can be reliably prevented. By preventing disturbance of assist gas,
The generation of voids in the build-up layer due to the entrainment of the gas is avoided, and a high-quality build-up layer is obtained.

FIG. 6 shows the frequency of occurrence of defects in the build-up layer with respect to the ratio b / a. In the case where the ratio is less than 1/4, the assist gas is disturbed.
This shows a state in which vibrations occur, and these cause defects in the build-up layers.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a laser cladding apparatus having a powder material charging nozzle according to an embodiment of the present invention.

FIG. 2 is a sectional view showing an internal structure of a powder material charging nozzle of FIG.

FIG. 3 is a right side view of FIG. 2;

FIG. 4 is a front view of a support bracket used for the powder material charging nozzle of FIG. 2;

FIG. 5 is a cross-sectional view of the vicinity of an overlapped portion in which a start end portion and a terminal end portion of a build-up layer are overlapped.

FIG. 6 is an explanatory diagram showing the frequency of occurrence of defects in the build-up layer with respect to the mounting position of the support bracket.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piston (metal base material) 7 Powder material 9 Laser beam 17 Powder material injection nozzle 19 Nozzle main body 21 Powder nozzle port (inner cylinder part) 23 Gas nozzle port (outer cylinder part) 31 Mesh (rectifying part) 33 Support bracket 33a Assist gas Through hole 33b Through hole

Claims (5)

[Claims] When a powder material made of another metal is melted by irradiating a laser beam on a surface of a metal base material to form a build-up layer, a powder material charging nozzle for charging the powder material includes an external nozzle. A nozzle body which is fixed to the cladding apparatus body side by introducing a powder material from the inside, and an inner cylindrical portion having one end fixed to the nozzle body and having a powder discharge port for discharging the introduced powder material from the other end side. A space formed between the inner cylinder and an assist gas for covering the periphery of the base end side of the inner cylinder and blowing off the plasma generated during the laser beam irradiation introduced into the nozzle body. A powder material injection nozzle, comprising: an outer tubular portion that is sent to the outside through a portion; and a support bracket that supports the distal end of the inner tubular portion with respect to a distal end side from a base end of the inner tubular portion. 2. A rectifying portion for rectifying the flow of assist gas is provided in a space between the inner cylindrical portion and the outer cylindrical portion, and a support bracket is provided on a base end side of the inner cylindrical portion with respect to the rectifying portion. The powder material injection nozzle according to claim 1, wherein 3. The support bracket has a ratio b / a of a distance a from the rectifying portion to the fixing portion of the inner cylindrical portion to the nozzle body and a distance b from the rectifying portion to the support bracket, １ ／ <b.
3. The powder material injection nozzle according to claim 2, wherein the nozzle is provided at a position where / a <1/2. 4. The support bracket has a disk shape, an outer peripheral surface of which is fixed to an inner peripheral surface of the outer cylindrical portion, and an inner peripheral surface of a through hole provided at the center is formed on an outer peripheral surface of the inner cylindrical portion. The powder material injection nozzle according to any one of claims 1 to 3, wherein the nozzle is fixed and includes a plurality of assist gas passage holes in a circumferential direction. 5. When a powder material made of another metal is melted by irradiating a laser beam on a surface of a metal base material to form a build-up layer, vibration of a powder material charging nozzle for charging the powder material is prevented. In the method, one end is fixed to a nozzle body which is fixed to the cladding apparatus main body side by introducing a powder material from the outside, and has an inner cylindrical portion provided with a powder discharge port for discharging the introduced powder material from the other end side. A space formed between the inner cylindrical portion and an assist gas for covering around the base end side of the inner cylindrical portion and blowing the plasma generated during the laser beam irradiation introduced into the nozzle body. A method of preventing vibration of a powder material injection nozzle, wherein the vibration is prevented by supporting the outer cylindrical portion which is sent to the outside through the outside.