JPH0310770A - Centrifugal type shot peening machine - Google Patents

Abstract

PURPOSE:To reliably blow off steel balls entering in a recessed part by means of high pressure air by providing air nozzles which are opened in the steel ball shot direction of an impeller and blow high pressure air against a substance to be cured at which the steel balls are shot. CONSTITUTION:Simultaneously with shooting of steel balls S... at a gear G, high pressure air is blown through air nozzles 10 and 10. Even when the steel ball S enters the recessed part of the gear G, it is blown off by means of high pressure air, and is prevented from being guided out in a state to enter in the recessed part. High pressure air is always blown against the gear G through the nozzles 10 and 10, and the gear is forcibly cooled. Further, though the gear G is heated by striking a number of the steel balls S... thereagainst, the gear is exposed to high pressure air through the nozzles 11 and 11, resulting in the generation of no heat.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an improvement in a centrifugal shot peening machine.

(Prior Art) For example, a centrifugal shot peening machine is known as an apparatus for cold working the surface of a gear or a leaf spring to generate compressive stress and thereby harden the surface. Hardened objects such as gears or leaf springs that have been surface hardened using this type of device have significantly improved fatigue limits and wear resistance.

To explain the general structure of the centrifugal shot peening machine, objects to be cured, such as gears, are placed and conveyed on a conveyor that is driven to run endlessly in the horizontal direction. An impeller is disposed at a predetermined position and above the conveyor. A fly ball collection section is provided in the lower part, which has a large opening area relative to the conveyor side which is the upper surface side, and the collected steel balls are provided on one side of the bottom part. A screw is provided for transferring to the outlet. A supply device is provided opposite the discharge port of the steel ball collecting section.

This is made by running a conveyor vertically endlessly, on which a plurality of boxes are provided at predetermined intervals on one surface.

The upper end of the separator is disposed to face the second-most upper end of the supply device, and the lower end of the separator faces the impeller. The above-mentioned impeller has a fixed wheel part at its axis that temporarily receives and collects the steel balls delivered from the separator and has a delivery hole bored on its circumference for delivering a predetermined number of steel balls. . An impeller main body, which has a plurality of shot chambers divided into radial sections, is rotatably fitted onto the circumferential surface of the wheel portion. A through hole is provided only at a portion of each shot portion that rotatably fits into the wheel portion, and when the shot portion communicates with the delivery hole, the steel ball is received into the shot chamber. Further, each shot chamber is opened only on the peripheral end surface.

Thus, a large number of steel balls delivered from the separator to the wheel portion of the impeller are temporarily collected there. The impeller main body is driven to rotate, and when the through hole of the shot part communicates with the delivery hole of the wheel part, a predetermined amount of steel balls are introduced into the shot chamber. Since the impeller main body is rotationally driven, these steel balls are blown away from the opening surface of the peripheral end of the shot chamber by centrifugal force. That is, the object to be cured is shot and transported to a conveyor in the direction of the shot.

The object to be hardened is continuously subjected to extremely strong impacts from a large number of steel balls over its entire surface. the result.

The surface of the material to be cured will be subjected to cold working.

Obtain curing as described above. The steel balls that collide with the object to be heated fall into the steel ball collection section and are discharged from the discharge port.

The receiver of the supply device is placed into the box. Then, as the conveyor runs, it is transferred upward, and is thrown into the upper end of the separator to be used for the next shot.

FIG. 2 schematically shows the configuration of the main parts of such a centrifugal shot peening machine. Reference numeral 1 denotes an impeller, and a fixed wheel portion 3 is provided at the axis of an impeller main body 2 that is rotationally driven by a drive motor, and steel balls S are guided from a separator (not shown). Above impeller body 2
The shot chamber 4 constituting the steel ball S receives the steel balls S and shoots them using the centrifugal force caused by rotation. A hardened object, for example a gear G, is located in the shot direction, and all the steel balls S collide with the gear G. The diameter of the steel balls S... is extremely small, and a large number of steel balls S...
... hits the circumferential surface of gear 6 without any gaps, so this surface is uniformly cold-worked. Steel ball S with a gear G shot
... falls into the steel ball collecting section 5 and is supplied again for the next shot operation.

(Problems to be Solved by the Invention) Although the shot peening process has such advantages, it also has disadvantages.

In other words, in the case of an object to be hardened, such as the gear G, which has a complicated shape and has fine irregularities, the diameter of the steel ball S is extremely small and the surface of the gear G is shot strongly, so that the gear G is hardened. It is often the case that the machining process is completed and the material remains inside the recess (groove) of the machine and is led out of the device. If the above-mentioned steel ball S is assembled into a predetermined device and operated in an undiscovered state, there is a risk that one component may be damaged. Therefore, after finishing the machining, it is necessary to always inspect the steel ball S, which takes time and effort to remove the steel ball S that has entered the recess. Furthermore, the gear G, which is continuously hit by a large number of steel balls S, generates heat due to the impact. There is no noticeable change in the appearance of this metal crystal, but the stress caused by cold working gradually decreases. This corresponds to the so-called recovery period of annealing, and the hardening obtained by shot is reduced.

The present invention has been made in view of the above-mentioned circumstances, and is capable of blowing away steel balls that have entered the recesses of the object to be hardened due to shot peening, even if the object to be hardened has a complicated shape, and to It is an object of the present invention to provide a centrifugal shot peening machine that prevents a decrease in surface compressive stress by forced cooling and obtains a predetermined surface hardening.

[Structure of the invention]

(Means for solving problems) A large number of extremely small diameter steel balls are supplied to the impeller.

The impeller is rotationally driven to shoot the steel balls onto a material to be hardened, and the surface of the material to be hardened is cold-worked to obtain surface hardening due to the generation of compressive stress.

This centrifugal shot peening machine is characterized in that an air nozzle is opened toward the shot direction of the steel balls of the impeller, and high-pressure air is blown onto the material to be hardened together with the steel balls.

(Function) By spraying high-pressure air from the working air nozzle together with a shot of the steel balls against the object to be hardened, the steel balls that have entered the recesses of the object to be hardened are blown away by the high-pressure air, eliminating the need for separate removal. At the same time, the material to be cured is forcibly cooled by high-pressure air. That is,
It does not have any effect on the surface compressive stress generated by cold working associated with shot pinning.

(Embodiment) An embodiment of the present invention will be described below based on FIG. 1. Except for the newly provided air nozzle 10.10, the other components are the same as those previously explained in FIG. 2. Since they are completely the same, the same numbers will be given and new explanations will be omitted. The air nozzle 10°10 opens toward the shot direction of the steel balls S shot from the shot chamber 4 of the impeller body 2. Air vibes 11, 11 to which each air nozzle 10.10 is connected communicate with a high-pressure air source (not shown).

Therefore, the shot chamber 4 that constitutes the impeller body 2 is
A steel ball S... is received through the wheel portion 3, and is shot onto a hardened object, such as a gear G, by the centrifugal force accompanying the rotation. The diameter of the steel ball S... is extremely small,
In addition, since a large number of steel balls S hit the circumferential surface of gear 0 without any gaps, this surface is uniformly cold-worked, compressive stress is generated, and the surface is hardened.

High-pressure air is blown from the air nozzle 11.11 together with the shot of the steel ball S against the gear G. As a result, even if the steel ball S enters the recess of the gear G, it will be blown away by the high-pressure air and will not be drawn out of the machine while remaining in the recess. At the same time, the gear G is constantly blown with high pressure air from the air nozzle 10, 10, and is forcedly cooled. Although the gear G is heated by being hit by a large number of steel balls S, it does not have heat because it is exposed to high pressure air from the air nozzles 11 and 11. That is, there is no influence on the surface compressive stress generated by cold working associated with shot peening.

Note that the steel balls S shot into the gear G fall into the steel ball collecting section 5 and are again supplied to the next shot, as in the conventional case.

〔Effect of the invention〕

As explained above, according to the present invention, even if the object to be cured has a complicated shape, the high-pressure air reliably blows out the steel balls that have entered the four parts, eliminating the need for additional inspection and saving time and effort. No need to worry.

Moreover, since the material to be cured is forcibly cooled by high-pressure air, there is no reduction in compressive stress generated during cold working, and the shot peening effect is ensured.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the main part of a centrifugal shot peening machine showing an embodiment of the present invention, and FIG. 2 is a schematic diagram of the main part of a centrifugal shot peening machine showing a conventional example of the invention. S... Steel ball, 1... Impeller, G... Hardened material (
Gear), 10...Air nozzle.

Claims (1)

[Claims] A large number of extremely small diameter steel balls are supplied to an impeller, and the impeller is driven to rotate to shoot the steel balls onto the object to be hardened.
In a device that cold-works the surface of a workpiece to obtain surface hardening by generating compressive stress, the impeller opens toward the shot direction of the steel balls and blows high-pressure air onto the workpiece where the steel balls are shot. A centrifugal shot peening machine featuring a nozzle.