JPS643634Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a tool abnormality detection device for a machine tool such as a cutting tool, and more particularly to a mounting device for a sensor that detects acoustic emission (referred to as AE).

In machine tools such as drilling machines and milling machines where the tool is attached to the spindle, it is impossible to directly attach the AE sensor to the tool or spindle in order to detect abnormalities in the machining. I had no choice but to attach it to the main shaft support. For example, the one published in Japanese Patent Application Laid-Open No. 55-37273 is
It is mounted on the feed shaft support member of the drill head in contact with the feed shaft. However, it is possible to extract the electric signal for detecting the resonance frequency of the workpiece by pressing a sensor against the center of the spindle, as described in Japanese Patent Application Laid-Open No. 57-48450, for example.
Although it is well known in the above publication, in the case of an AE sensor, such an installation is not reliable due to wear and relative positional deviation of the contact portion on the main shaft side. For this reason, since conventional products are attached to the spindle support, bearing noise, noise from cutting oil equipment and chips, and changes in frequency characteristics or vibration modes due to acoustic effects of the spindle support cannot be avoided, and such support parts Due to this, the AE signal generated by the tool was attenuated significantly, making it impossible to obtain an accurate AE signal.

(Purpose of the invention) The purpose of the invention is to directly detect the abnormal AE signal of the tool transmitted to the spindle by pressing the AE sensor that detects the AE signal directly against the spindle in a tool abnormality detection device attached to the spindle. By taking out the AE signal, noise, frequency change, vibration mode change, or AE
The purpose is to prevent signal attenuation.

(Structure and effect of the invention) Therefore, the present invention includes a base fixed to the back surface of the spindle supported by the spindle support, and a high-speed steel, carbide ceramic, or A centering tool member including a tip made of a hard material such as diamond, and an AE sensor supported movably in the axial direction with respect to the main shaft support part are fixed on one side and are in contact with the tip on the other side. This tool abnormality detection device includes a tip member having a low-friction surface disposed at the tip, and a pressing device that presses the AE sensor toward the tip. With this configuration, the AE sensor is mounted directly on the spindle, so there is extremely little attenuation of the AE signal generated by the tool, and there is also less noise caused by bearing noise, cutting oil equipment, and chips, and there is also less noise due to the acoustic effects of the spindle support member. This eliminates any alterations in frequency characteristics or vibration modes due to
It is now capable of receiving AE signals, greatly increasing the accuracy of tool abnormality detection.

(Description of an Embodiment) An embodiment of the present invention will be described with reference to the drawings. A spindle 1 is rotatably supported by a spindle support part 13, such as a spindle head, by a bearing 8.
A tool chuck 7 holding a tool 6 such as a drill is attached to its tip. Back side 1 of main shaft 1
1, that is, on the opposite side of the main shaft, a centering tool member 2 having a base 12 having approximately the same outer diameter as the main shaft 1 is fixed with its tip 10 and the center of rotation aligned with the main shaft axis. The tip 10 is made of a hard, low friction, wear material such as high speed steel, cemented carbide or diamond. Supported so as to be movable in the axial direction with respect to the main shaft support part 13
A chip member 3 having a flat, low-wear, low-friction surface 14 is fixed to one surface 15 of the AE sensor 4. A spring 5, ie, a pressing device, presses the AE sensor 4 so as to press the pointed end 10 of the tip member 3 with an appropriate force, and the spring 5 is supported at a fixed position with respect to the main shaft support portion 13. 9 is a pulley, 16 is an AE signal extraction wire, 17
is the work. The tip 10 and the low friction surface 14 preferably have a mirror finish to reduce friction. In addition, the AE sensor 4 and spring 5 are
It is preferable that the spindle support part 13 be supported via a vibration absorbing material so as to cut out vibrations from the main shaft support part 13 or the machine body (not shown) that supports it. Note that in order to make the resonance frequency higher than the AE signal frequency component, it is desirable that the direct diameter of the core tool member 2 and the tip member 3 is not too large.

With this configuration, the AE waves generated by the tool 6 and the workpiece 17 can be detected directly from the spindle by the AE signal transmitted through the spindle 1. That is, the vibration is transmitted to the tip 10 and the low friction surface 14, which are the contact points of the corer tool member 2 and the tip member 3 fixed to the main shaft 1, and is detected by the AE sensor 4. With respect to the propagation of AE waves (mainly vertical waves), attenuation from the coring tool member 2 to the tip member 3 is extremely small. In addition, there is less noise from bearings, cutting oil equipment, and chips, and the spindle support part 3
Changes in frequency characteristics or vibration modes due to acoustic effects cause the AE sensor 4 and spring 5 to
This can be eliminated by not being affected by this effect. Therefore, since an extremely accurate AE signal can be received, the accuracy of abnormality detection of the tool 6 can be greatly improved.

[Brief explanation of the drawing]

The drawing is a schematic side view showing an embodiment of the present invention. 1...Main shaft, 2...Corner tool member, 3...
Chip member, 4... AE sensor, 5... Pressing device, 10... Tip, 11... Back, 12... Base, 13... Spindle support part, 14... Low friction surface, 1
5... Page 1.

Claims (1)

[Scope of utility model registration request] Main shaft 1 supported by main shaft support part 13, back surface 11
a centering tool member 2 comprising a base 12 secured to the base 12 and a tip 10 made of a hard material, such as high speed steel, cemented carbide or diamond, projecting from said base in a direction counter to the main axis and on the main axis; ,
A tip member 3 having one surface 15 fixed to an AE sensor 4 movably supported in the axial direction with respect to the main shaft support portion 13 and having a low friction surface 14 disposed on the other surface so as to be in contact with the tip 10. , a pressing device 5 that presses the AE sensor 4 toward the tip 10, and a tool abnormality detection device.