This invention relates to an apparatus that can detect the intensity of shot peening while the peening is being performed, and it also relates to a replacement part or unit for the apparatus.
Conventionally, the degree to which shot peening is performed is measured by a method of observing the average projection intensity of shot or a method of observing the projection density of shot. In the method of observing the projection intensity of shot, a piece of thin steel plate bends back when a shot collides with it, and the height of the bend (the height of the arc) is measured by a gage. In the method of examining the projection density of shot, the shot are projected onto a piece of thin steel plate and a picture of the dents formed in the steel plate by the shot is taken to observe the rate (or the coverage) of the dents.
However, since in both methods the steel plate is taken out to observe it after the shot peening is performed, they are not available if the shot peening is performed while the amount of the shot is being observed, so as to perform it under the optimum conditions, although they are suitable for predetermining the conditions for projecting the shot.
Thus the applicant discloses a device for detecting the intensity of shot peening, which is described in JP 4-19071 A. The device comprises a shot collision propagating member, which is structured as one body or connected parts of a shot collision portion for generating an elastic wave when a shot collides with it and a propagating portion for propagating the generated elastic wave; an outer case of a U-shaped cross section which the shot collision propagating member bridges and is fixed to; a transducer connected to the shot collision propagating member for receiving the propagating elastic wave and converting it to high frequency signals to output them; and a measuring circuit including a counter circuit connected to the transducer for detecting the number of generated solitary waves of the high frequency signals and a peak value detecting circuit for detecting the peak values of the solitary waves of the high frequency signals.
However, the device is large and it is difficult to use in some cases. Further, its portability and work efficiency are poor.
Further, since the recent, popular shot peening by fine shot (for example, 20-150 xcexcm in diameter) uses a great number of shot, the device discussed above cannot treat the signals of each collision as a solitary wave. Thereby it fails to measure the intensity of the shot peening. In view of this problem, the applicant discloses (in JP2000-94330 A) a device for automatically detecting the intensity of shot peening that uses fine shot. However, in these conventional devices for detecting the intensity of shot peening, the output from them tends to be changed, or affected, due to any change in temperature, and the maintenance of them takes much time. As a result of keenly studying these problems, the inventors have conceived the present invention.
The present invention has been conceived in view of these problems. The purpose of it is to provide an apparatus for automatically detecting the amount and the intensity of shot during shot peening, and which is portable and works effectively. Another purpose of it is to provide a replacement unit for the apparatus, for which unit the initial setting and maintenance are easy.
To attain the above end, the apparatus of the present invention is an improved apparatus for detecting the intensity of shot peening by detecting at least one of the number of shot that have collided with the apparatus and the intensity of the colliding shot, comprising a box-like case having an opening at its top; a first resilient member disposed under the top of the case; a hollow supporting member resiliently supported in the case between the first resilient member and a second resilient member which is mounted in the case, the hollow supporting member including a third resilient member mounted therein; a shot collision propagating member supported by the hollow supporting member to close the opening of the top of the box-like case by way of the first resilient member, the shot collision propagating member producing and propagating an elastic wave when colliding with a shot; a transducer, for receiving the propagating elastic wave from the shot collision propagating member and converting the elastic wave to high frequency signals, disposed in the hollow supporting member and resiliently supported by the third resilient member such that a top surface of the transducer contacts a lower surface of the shot collision propagating member; and a cable passing through the hollow supporting member so as to be connected at one end to the transducer and to be connected at the other end to a measuring circuit.
To attain the above end, the replacement unit for the apparatus includes the hollow supporting member including the third resilient member, the transducer, and the shot collision propagating member.
According to the apparatus of the present invention, the amount and the mean projection intensity of shot can be detected during shot peening without being affected by the temperature. Further, the apparatus has advantages in portability and working efficiency.
The inventors have found that the reason for the change in the output of the conventional device for detecting the intensity of shot peening, in particular, for the change when fine shot are used, is that an adhesive is used between the contacting surfaces of the shot collision propagating member and the transducer. Thus, to avoid any effect of the temperature, they chose the surface contact by using a resilient support. The reason that the maintenance takes much time is that there are problems such as the contacting surfaces peeling off during the maintenance because of the adhesive being used between them.
Further, by using the replacement unit of the invention, maintaining the apparatus will be easy, since the maintenance requires that only the unit be tested.