JPH07100302B2 - Nozzle type shot peening machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention relates to a nozzle type shot peening apparatus for performing surface treatment of, for example, a metal material.

(Prior Art) Conventionally, a shot, which is a small metal ball, is projected on the surface of a portion such as a spring or gear used in a vehicle that receives stress concentration to increase the compressive stress and improve the fatigue strength. Shot peening equipment is known. According to this apparatus, a grain boundary oxide layer is formed on the surface of a work that has been carburized and quenched, and the fatigue strength is reduced. However, this layer can be removed by shot projection, and the peening effect is extremely large. .

As such a shot peening device, a nozzle type device is shown in FIG. 4, for example. In the figure, in the shot peening apparatus 101, the negative pressure when the compressed air generated by the compressor 103 passes through the compressed air pipe 105, the shot 109 of the hopper 107 is mixed with the compressed air, and accelerated from the nozzle 111. The shot 109 is projected onto the work 113.

(Problems to be Solved by the Invention) In such a conventional nozzle type shot peening apparatus, compressed air from the compressor 103 is continuously ejected from the nozzle 111 at a constant pressure. Therefore, there is a case where it is desired to project with a high pressure in order to form a high compressive residual stress from the surface to a deeper position, but in the above-mentioned apparatus, the shot 109 is shot with a different pressure.
Cannot project to 13.

On the other hand, by using two shot peening devices having different pressures for one work 113,
The shot 109 can be projected onto the work 113 with different pressures.

However, when two shot peening devices are used, there is a problem in that the entire device becomes large and the work space is increased.

The present invention has been made in view of the above-mentioned problems, and it is possible to change the depth of the shot by projecting the shot on the work with different pressures while having a configuration that can downsize the entire apparatus. An object is to provide a nozzle type shot peening apparatus.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention is a nozzle type shot in which a shot is mixed with compressed air ejected from a nozzle and an accelerated shot is projected onto a work. The peening apparatus is configured to be switchable between a first state in which the compressed air is continuously ejected and a second state in which the compressed air is ejected intermittently, and a projection speed of the shot is variable.

Also, a compressor for generating compressed air, a compressed air pipe having one end connected to the compressor, a shot supply unit connected to an intermediate portion of the compressed air pipe for mixing shots into the compressed air, A nozzle type shot peening device which is provided at the other end of the compressed air pipe and ejects compressed air mixed with a shot to project an accelerated shot onto a work, wherein the shot side of the compressed air pipe is closer to the compressor side. An on-off valve that is provided to open and close the compressed air and a control means that can switch between a first state in which the on-off valve is continuously opened or closed and a second state in which the on-off valve is opened and closed intermittently are provided.

(Operation) In the above configuration, by switching to the first state,
The pressure of the shots in which compressed air is continuously ejected and projected onto the work is almost constant. On the other hand, by switching to the second state, the pressure of the shot that the compressed air is jetted intermittently and is projected onto the work temporarily increases.

Further, when the opening and closing of the on-off valve is controlled by the control means, the compressed air generated by the compressor flows continuously or intermittently in the compressed air pipe, and when the compressed air is continuously ejected from the nozzle, it is projected onto the work. While the pressure of the shot is almost constant, the pressure of the shot temporarily rises when it is ejected intermittently.

(Embodiment) An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a nozzle type shot peening apparatus according to an embodiment of the present invention.

First, the structure will be described.
A compressor 3 for generating compressed air and a hopper 7 in which shots 5 are stored are provided. One end of the compressed air pipe 9 is connected to the compressor 3 and the compressed air pipe 9
A nozzle 13 facing the inside of the shot chamber 11 is provided at the other end of the. One end of a shot supply pipe 15 as a shot supply unit is connected to the hopper 7, and the other end of the shot supply pipe 15 is connected to an intermediate portion 9a of the compressed air pipe 9 as a shot supply unit.

An electromagnetic valve 17, which is an opening / closing valve for opening / closing the compressed air pipe 9, is provided on the compressor 3 side of the compressed air pipe 9 from the intermediate portion 9a. The solenoid valve 17 is opened by turning on a solenoid valve switch (not shown). A pulse generator 19 as a control means is connected to the solenoid valve 17, and the pulse generator 19
Operates by turning on a pulse generator switch (not shown). When the solenoid valve 17 and the pulse generator switch (not shown) are turned on,
Opening and closing are controlled at appropriate timing according to the pulse generated by the pulse generator 19.

A shot supply pipe opening / closing valve 21 that opens and closes the shot supply pipe 15 is provided in the middle of the shot supply pipe 15. When the shot supply pipe opening / closing valve 21 is opened when the solenoid valve 17 is opened and the compressed air is flowing in the compressed air pipe 19, the shot 5 in the hopper 7 is compressed by the negative pressure in the compressed air pipe 9. Mix in.

In the shot chamber 11, a turntable 23 rotatable with respect to the shot chamber 11 is provided, and a gear 25 as a work is placed on the turntable 23, for example.

Next, the operation will be described based on the flowchart shown in FIG.

In the above configuration, after turning on the start switch in step S101, turn on the solenoid valve switch in step S103,
When the pulse generator switch is turned on in step S105, the solenoid valve 17 opens and closes according to the pulse of the pulse generator 19. In this state, in step S107, when the shot supply pipe opening / closing valve 21 is opened, the shot 5 in the hopper 7 is attracted by negative pressure and the intermediate portion 9a of the compressed air pipe 9 is attracted.
In step S109, the compressed air is intermittently ejected from the nozzle 13 to temporarily increase the pressure per shot, and the projection speed of the shot 5 projected onto the gear 25 in step S109. Is temporarily increased to increase the so-called arc height value.

On the other hand, even though the solenoid valve switch is turned on in step S103, the solenoid valve 17 maintains the open state without turning on the pulse generator switch. Therefore, in the first state, since the compressed air is continuously ejected from the nozzle 13 at a constant pressure, the shot supply pipe opening / closing valve 21 is opened and the shot speed of the shot 5 mixed in the compressed air is constant. It has a certain arc height value.

As described above, in this embodiment, the shot 5 can be projected onto the gear 25 at different pressures by one device. Therefore, for example, shot 5 is first projected onto the surface of the carburized gear 25 with a high arc height value to remove the incompletely hardened layer which is an abnormal layer, and then shot 5 is projected with a low arc height value. As a result, the compressive stress of the entire gear 25 is increased and the fatigue strength is improved.

Further, a single apparatus can obtain stable quality by projecting the shot 5 with different arc height values on the tooth root and tooth surface of the gear 25.

Needless to say, the shot 5 may be projected onto different works at a pressure corresponding to each work.

Such different flow velocities of the shot 5 are shown in FIG. 3, for example. That is, it is understood that when the shots 5 are continuously projected from the nozzle 13, a certain constant pressure is maintained as in the state A in the figure, and when the shots 5 are intermittently projected, the pressure is temporarily increased as in the state B.

[Effects of the Invention] As described above, according to the present invention, since the shot projection speed can be varied with one device, the entire device can be downsized, but the same work or different works can be achieved. It is possible to project an appropriate shot according to the above condition and improve the quality of the work.

By ejecting the compressed air continuously or intermittently, the pressure of the compressed air can be temporarily increased, and it becomes possible to project a shot with a high arc height value and to change the arc height value. By projecting a shot, stable quality of springs, gears, etc. can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic overall configuration diagram of a nozzle type shot peening apparatus according to an embodiment of the present invention, FIG. 2 is a flow chart showing the operation, and FIG. 3 is a diagram showing shot flow velocity,
FIG. 4 is a schematic overall configuration diagram of a nozzle type shot peening apparatus according to a conventional example. 1 …… Shot peening device 3 …… Compressor 5 …… Shot 3 …… Compressed air pipe 9a …… Intermediate part (shot supply part) 13 …… Nozzle 17 …… Solenoid valve (open / close valve) 19 …… Pulse generator 25 ...... Gear (work)

Claims (2)

[Claims] 1. A nozzle-type shot peening apparatus for projecting a shot that is accelerated by mixing a shot with compressed air ejected from a nozzle, and a first state in which the compressed air is ejected continuously and intermittently. A nozzle type shot peening apparatus having a switching selection means for switching to a second state in which the jetting is performed to select one of the states. 2. A compressor for generating compressed air, a compressed air pipe having one end connected to the compressor, and a shot supply unit connected to an intermediate portion of the compressed air pipe for mixing shots into the compressed air. And a nozzle provided on the other end of the compressed air pipe for ejecting compressed air mixed with a shot to project an accelerated shot onto a work, the nozzle type shot peening apparatus comprising: It is possible to switch between an open / close valve that is provided closer to the compressor than the shot supply unit and that opens and closes the compressed air pipe, and a first state that continuously opens or closes the open / close valve and a second state that opens and closes intermittently. Nozzle type shot peening apparatus, which is provided with various control means.