JPH027645Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention is applicable to, for example, when manufacturing a low-cost press mold suitable for small-volume production, the mold body is formed of an inexpensive and relatively soft metal material or synthetic resin,
The mold surface part relates to a nozzle structure in a metal spraying device used to form a hard metal coating layer to ensure the required hardness. [Prior Art] Conventionally, the nozzle 20 of this type of metal spraying apparatus has a pair of thermal spraying metal wires 14 and
4' A guide tube 13, 13' is provided so that the tips of the metal wires 14, 14' are gathered in a V-shape, and compressed gas is injected so as to be concentrated in front of the gathering position of the metal wires 14, 14'. A metal spraying device equipped with an injection port 11 is generally used, and according to such a metal spraying device, a conical low pressure (that is, a semi-vacuum) is formed by the gas flow injected from the compressed gas injection port 11. A pair of thermal spraying metal wires 14, 1 within area A
4' gather in a V-shape and generate an arc discharge, whereby the molten spherical metal particles move to the gathering part where the forward jetted gas flow is largest, and become fine particles with many dendritic shapes, increasing the surface area. By enlarging the solid particles, a cooling force is generated, which causes them to scatter as solid particles, become entangled with each other on the adhering surface of the sprayed object, and undergo a chain reaction of compression to form a coating layer. By the way, in recent years, chromium-based materials, which are high melting point materials, have been used as thermal spray metals to obtain particularly hard coating layers.
The use of metals such as stainless steel has been tested and considered, but when this type of metal is used for thermal spraying using conventional metal spraying equipment, the degree of vacuum in cyclone A is not sufficient. Therefore, there was a problem in that the tip of the metal wire was not sufficiently melted and the molten particles became coarse, resulting in unmelted slag adhering to the coating layer and small pores caused by air bubbles. [Purpose of the invention] In order to solve the above-mentioned problems of conventional metal thermal spraying equipment, the present invention provides a nozzle structure in which another compressed gas injection port is provided in front of the original compressed gas injection port. With the goal. [Structure of the invention] The present invention has been made to achieve the above-mentioned object. A compressed gas injection port is provided with a gap having a tapered cross section that approaches the center toward the front in order to cause an arc discharge at the tip gathering part to form molten granules, and to inject compressed gas so as to concentrate in front of the discharge position. , in a metal spraying apparatus in which the gas injected from the injection port atomizes and scatters molten metal and attaches it to the object to be sprayed; This is a nozzle structure in a metal thermal spraying apparatus characterized by providing another compressed gas injection port formed by a gap in a tapered cross section for injecting gas. [Example] Hereinafter, an example of the present invention will be described based on the drawings. In FIG. 1, reference numeral 1 denotes a metal thermal spray gun as an embodiment of the metal thermal spraying apparatus of the present invention, and a nozzle 3 is protruded from the front end of the main body 1a.
Flexible hoses 2, 2' for passing metal wires 14, 14' for thermal spraying (hereinafter referred to as metal wires 14, 14') are connected to the rear end, and a lower surface of the rear end of the main body 1a is connected to A grip portion 5 is provided in a downwardly protruding manner, and a cable 4 leading to a power source is connected to the front side of the lower surface. Next, the structure of the nozzle 3 will be explained. In FIG. 2, the nozzle 3 is integrated by screwing the rear end of the front nozzle 10 and the front end of the rear nozzle 8 onto the front and rear ends of the intermediate nozzle 9, respectively. The rear nozzle 8 is formed in a cylindrical shape, and a wall 8c is integrally formed inside the front end portion thereof, in which a tapered hole 8b that expands rearward from an opening of a predetermined diameter at the front end is formed. Along the inner surface of the tapered hole 8b, guide tubes 13, 13' are provided for guiding a pair of metal wires 14, 14' inside, and the metal wires protruding from the guide tubes 13, 13' and the tapered hole 8b are provided. Both ends of the wires 14, 14' are V-shaped and concentrated in front of the ends of the guide tubes 13, 13'. The guide tubes 13, 13' extend through the rear nozzle 8 and the inside of the thermal spray gun body 1a, and also extend through the interior of the spray gun body 1a.
The flexible hoses 2, 2' described above are connected to the rear end of a, and the guide tubes 13, 13', the flexible hoses 2,
The metal wires 14, 14' passed through the interior of the metal wires 2' reach a winding reel (not shown). The intermediate nozzle 9 is provided with a hole 9b in the center, and the hole 9b has a tapered cross section such that its rear end has a slight gap 11 with the outer surface of the tip of the wall 8c of the rear nozzle 8. The front end of the gap 11 is the first compressed gas injection port 11a (hereinafter referred to as the first injection port 11a).
At the rear of the first injection port 11a, a space 8d is formed by the rear nozzle 8 and the intermediate nozzle 9, and a gas hose shown in FIG. Connect 6. Next, as a feature of the present invention, the first injection port 1
Furthermore, in front of 1a, the first injection port 11a
The second compressed gas injection port (hereinafter referred to as the second
12a (referred to as an injection port) 12a is provided. That is, the tapered cross section 8 of the wall 8c of the rear nozzle 8 is removed so that the front end outer peripheral portion of the intermediate nozzle 9 is removed.
A tapered cross section 9c is formed substantially parallel to c'. Further, the front nozzle 10 has a hole 10b in the center, and the center of the hole 10b forms a tapered cross-section 10c' with a slight gap 12 between it and the tapered cross-section 9c of the intermediate nozzle 9. , the front end of the gap 12 becomes the second injection port 12a. The hole 10b widens in a tapered manner in front of the second injection port 12a. The metal wires 14, 14' are connected to the guide hoses 2, 2' by a drive device (not shown) provided in the main body 1a.
It is guided by guide tubes 13, 13' and fed forward,
In the main body 1a, the metal wires 14, 14' are always in contact with the cable 4 to collect current, and a predetermined DC voltage is applied thereto. [Operation] The operation when metal spraying is performed using the metal spray gun of the present invention configured as described above will be explained using specific examples. 13 Metal wire 14 made of chromium steel with a wire diameter of 1.1 mm,
14' is continuously fed at a speed of 200 mm/min, and the degree of vacuum in the cyclone A formed by the gas flow injected from the first injection port 11a is equal to that of the gas flow from the second injection port 12a. It was significantly improved by the gas flow and was applied to the gathering point of both metal wires 14, 14' within the low pressure area A.
By generating an arc with a DC voltage of 20 volts, the molten spherical metal particles move to the collecting part of the gas flow injected from the first injection port 11a, and become fine particles having a large number of dendritic shapes. As a result, the surface area expands and the molten metal particles are solidified, scattered, and attached to the press mold body.

[Table] [Effects] According to the nozzle structure of the thermal spray gun of the present invention, the conventional problems are solved, and the mold surface of the press mold body formed of relatively soft metal or synthetic resin is replaced with a hard high-melting point metal. Since the coating layer can be formed well depending on the material, cost reduction can be achieved without any problem by applying it to a press mold for small quantity production.

[Brief explanation of the drawing]

Figure 1 is an overall perspective view of the thermal spray gun of the present invention;
The figure is an enlarged sectional view taken along the line - in FIG. 1, and FIG. 3 is a sectional view similar to FIG. 2 showing a conventional example. 1... Metal spray gun, 3... Nozzle, 8... Rear nozzle, 8b... Tapered hole, 8c'... Tapered cross section, 9... Intermediate nozzle, 9b... Hole, 9c...
Tapered cross section, 10... Front nozzle, 10b...
Hole, 10c'...Tapered cross section, 11a...First
Compressed gas injection port, 12a...second compressed gas injection port.

Claims (1)

[Scope of utility model registration request] A plurality of metal wires for thermal spraying that are continuously supplied are arc-discharged at the tip gathering part of the metal wires by electric power supplied from a power source to form molten granules, and concentrated in front of the discharge position. In order to inject compressed gas, a compressed gas injection port is provided with a gap of a tapered cross section that approaches the center toward the front, and the gas injected from the injection port atomizes the molten metal and scatters it to the spray target. A metal thermal spraying device that is attached to an object, characterized in that another compressed gas injection port is provided with a gap of a tapered cross section that injects compressed gas so that the compressed gas is concentrated further forward than the concentrated position of the compressed air. Nozzle structure for metal spraying equipment.