JPS63265106A - Flatness judging method for grinding wheel - Google Patents

Abstract

PURPOSE:To judge whether a grinding wheel has undergone flat truing or not, by computing the elapsed time of acoustic emission, which is yielded when the abrasive grain of the grinding stone is broken. CONSTITUTION:A rotary dressor 3 and a grinding wheel 2 are rotated and a dressing device 1 is moved in the direction A. Then a grinding blade 4 is brought into contact with an outer surface 2a of the grinding wheel 2, and abrasive grain on the outer surface 2a is broken. At this time acoustic emission (referred to AE hereinafter) is generated. When the AE is detected, the movement of the dressing device 1 is stopped, and the movement of the grinding wheel 2 is started so that the rotary dressor 3 crosses the outer surface 2a of the grinding wheel 2. The generation of the high level AE from a starting time point PS of traverse to a terminating time point PE of traverse is detected. In this way, it is judged that the outer surface 2a of the grinding wheel 2 has undergone flat truing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for determining whether or not a grinding wheel surface has been trued flat during truing of a grinding wheel using a dresser.

[Description of Prior Art] As is well known, in grinding wheels, truing using a dresser is widely used in order to eliminate irregularities on the outer circumferential surface caused by partial wear of the grinding surface or missing abrasive grains and to flatten the outer circumferential surface. It is being done. Conventionally, whether or not the outer circumferential surface of a grinding wheel has been trued flat has been manually determined based on sparks and sounds during truing, or the feel of the outer circumferential surface of the grinding wheel. This not only causes variations in truing, such as the depth of cut becoming unnecessarily large, or, conversely, the necessary flatness not being achieved due to an insufficient depth of cut, but also requires skill and reduces the ease of truing. It was something that was missing.

[Object of the Invention] The present invention has been made based on the above viewpoint, and its purpose is to be able to determine whether or not a grinding wheel has been trued flat, and to minimize the depth of cut during truing. It is an object of the present invention to provide a method for determining the flatness of a grinding wheel that is particularly effective and contributes to ease of truing.

[Means for achieving the object] In the present invention, during truing of a grinding wheel by a dresser, acoustic emissions generated during the truing are detected, and the continuation of the detected acoustic emissions at a predetermined level or higher is performed. A grinding wheel that measures the time width, calculates the integrated value of the duration until the dresser crosses the outer peripheral surface of the grinding wheel, and determines whether or not the grinding wheel has been trued flat based on this integrated value. By the flatness determination method,
Achieve the above objectives.

That is, acoustic emissions are generated when the abrasive grains of the grinding wheel are crushed, so if there is an open part on the outer circumferential surface of the grinding wheel where the abrasive grains are not crushed, the acoustic emissions will be below a predetermined level.

Therefore, since the integrated value of the duration width of acoustic emissions above a predetermined level increases as the open area decreases, it is possible to determine whether or not truing has been done flatly based on the integrated value.

[Embodiments of the invention] Figures 1, 2(a) to 2(d) and 3(a)
) to FIG. 3(d) are diagrams explaining the principle of the method of the present invention. FIG. 1 shows the relationship between the dressing device and the grinding wheel. FIGS. 2(a) to 2(d) show a truing process in which the outer peripheral surface of the grinding wheel is shaped to be flat. Figures 3(a) to 3(d) are similar to Figures 2(a) to 2.
The process in Figure (d) shows the acoustic emission level generated, where the horizontal axis is time, Ps is the traverse start point, and PE is the traverse end point.

In FIG. 1, 1 is a dressing device, and 2 is a grinding wheel. The dressing device 1 has a rotary dresser 3 that is rotationally driven, and a diamond grinding blade 4 is provided on the outer periphery of the tip of the rotary dresser 3. The dressing device 1 is configured such that the grinding blade 4 of the rotary dresser 3 can come into contact with the outer peripheral surface 2a of the grinding wheel 2.
It is set diagonally to the Dressing equipment
can move in the direction of arrow A-B in the figure, and the grinding blade 4 comes into contact with the outer circumferential surface 2a of the grinding wheel 2 when moving in the direction of A. The grinding wheel 2 is rotationally driven by a shaft 5 and can move in the direction of arrow C-D in the figure.
This movement causes the rotary dresser 3 to cross the outer peripheral surface 2a of the grinding wheel 2.

With this configuration, when the rotary dresser 3 and the grinding wheel 2 are rotated and the dressing device l is moved in the direction A, the grinding blade 4 comes into contact with the outer peripheral surface 2a of the grinding wheel 2, and the abrasive grains on the outer peripheral surface 2a are It is crushed and Acoustic Kai Emissions (hereinafter referred to as AE) are generated. Upon detection of AE, the movement of the dressing device 1 is stopped and the movement of the grinding wheel 2 is started so that the rotary dresser 3 crosses the outer peripheral surface 2a of the grinding wheel 2 (traverse), as shown in Fig. 2 (a). As shown, the outer peripheral surface 2a of the grinding wheel 2 has openings 6a, 6b,
6c exists and the abrasive grains in the open portions 6a to 6c are not crushed during traverse, the AE is as shown in Fig. 3(a).
As shown in , the abrasive grains are at a low level in the open parts 6a to 6c where they are not crushed, and are at a high level in other parts. When the movement of the dressing device 1 and the grinding wheel 2 is controlled as described above and the second traverse is performed, as shown in FIG.
Assuming that the abrasive grains in the open portion 6b are crushed as shown in b), the time width of the high level portion of AE increases as shown in FIG. 3(b). Assuming that the abrasive grains in the open portion 6a are crushed as shown in FIG. 2(C) during the third traverse, A
As for E, the time width of the high level portion further increases as shown in FIG. 3(C). In the fourth traverse, the abrasive grains in the last open part 6c are crushed and the grinding wheel 2 is removed, as shown in FIG. 2(d).
Assuming that the outer circumferential surface 2a of the traverse becomes flat, a high level of AE occurs from the traverse start point PS to the traverse end point PE, as shown in FIG. 3(d).

Therefore, by detecting that a high level of AE has occurred from the traverse start time PS to the traverse end time PE, it can be determined that the outer circumferential surface 2a of the grinding wheel 2 has been trued flat.

FIG. 4 is a block diagram showing an embodiment of the method of the present invention, and FIG.
FIG. 1 is a block diagram showing an example of the dressing device 1 shown in FIG.

The dressing device having the configuration shown in FIG. 5 is the dressing device described in Japanese Patent Application Laid-Open No. 61-265269 previously filed by the present applicant, and the rotary dresser 3 of the dressing device 1 is fixed to a shaft 10. The shaft 10 is rotatably supported by the housing 12 via a bearing 11 and is rotationally driven by a drive shaft 13. Inside the housing 12, an AE sensor 1 is installed.
4 is provided, and a cutting fluid jetting passage 15 is also formed. The AE sensor 14 is housed in a through hole 16 formed in parallel with the shirt 10, and is attached to the rotary dresser 3.
A screw plug 17 that closes the open end of the through hole 16 facing the
The wave receiving surface is arranged so as to be in close contact with the inner surface of a, and is fixed by a spacer 17b and another screw plug 17c.

The cutting fluid jetting passage 15 is connected to the shaft 10 and the through hole 16.
It is formed in parallel with the rotary dresser 3 and has a spout 15a on the rotary dresser 3 side, and the other end is connected to the cutting fluid introduction pipe 18. High-pressure cutting fluid is supplied to the cutting fluid jetting passage 15 through a cutting fluid introducing pipe 18, and the cutting fluid is jetted toward the rotary dresser 3 from the jetting port 15a. AE that occurs when the abrasive grains of grinding wheel 2 (Fig. 1) are crushed
The wave is received by the AE sensor 14 via the rotary dresser 3 → the ejected cutting fluid → the housing 12 and the screw plug 17a, and is taken out to the outside via the lead 19 of the AE sensor 14.

In FIG. 4, an input circuit 20 receives the AE multiplied signal output from the AE sensor 14, performs processing such as noise removal and amplification, and then supplies the AE multiplied signal to the level comparison circuit 21. The level comparison circuit 21 provides an H level output for the AE multiplied signal that is higher than the reference level by comparison with the reference level.

The H level output of the level comparison circuit 21 is shown in FIG.
This corresponds to the high level AE in FIG. 3(d). 22 is a time measurement circuit which inputs the output of the level comparison circuit 21', measures the duration of the H level output of the level comparison circuit 21, and also integrates the duration of the duration from the start to the end of the traverse. A value T is determined and this integrated value T is provided to the time comparator circuit 23. The integrated value T is shown in Figures 3(a) to 3
The zero time comparison circuit 23 corresponding to the integrated value of the time width of the high level AE from the traverse start point PS to the traverse end point PE in FIG. When the integrated value T reaches a predetermined time To, a truing completion signal is given to the control device 24. The predetermined time To is determined based on the speed V (rubber speed) at which the rotary dresser 3 crosses the outer circumferential surface 2a of the grinding wheel 2 and the wheel width W of the grinding wheel 2.
Selected as MoW/V. The control device 24 controls the AE sensor 1
4 through the AE multiplied signal level comparison circuit 21 to control the rotation and movement of the dressing device 1 and the grinding wheel 2 as described in FIG. A traverse start signal is given in synchronization with the start of movement of the grinding wheel 2 for traverse, and is applied in synchronization with the start of movement of the grinding wheel 2 for traverse. The end signal is given by detecting that the rotary dresser 3 has crossed the outer peripheral surface 2a of the grinding wheel 2.

According to the above configuration, FIGS. 2(a) to 2(C)
), when a concave portion exists on the outer peripheral surface 2a of the grinding wheel 2, the AE multiplied signal level becomes below the reference level in the concave portion, so the integrated value T becomes smaller than the predetermined time To, No truing completion signal is given, whereas the grinding wheel 2 as shown in FIG. 2(d)
When the outer circumferential surface 2a of the outer circumferential surface 2a has no concave portions and becomes flat, an AE multiplied signal higher than the reference level is applied from the start to the end of the traverse, so that the integrated value T reaches the predetermined time To.
A truing completion signal indicating that flat truing has been performed will be given.

In the embodiments described above, the rotary dresser is equipped with an AE sensor, but it is also possible to use a non-rotating type dresser such as a single-sided diamond dresser. AE directly
An AE sensor can be provided to receive the waves.

[Effects of the Invention] As explained above, according to the present invention, attention is paid to the fact that the level of acoustic emissions generated when the abrasive grains of a grinding wheel are crushed changes depending on the surface condition of the grinding wheel, and By integrating the duration width of the acoustic emissions and determining whether or not the truing has been flat based on this integrated value, it is possible to easily know whether the truing has been flat or not.
Furthermore, it is possible to provide a method for determining the flatness of a grinding wheel that not only achieves the effect of flat truing with the minimum necessary cutting depth, but also contributes to automation of the grinding process.

[Brief explanation of drawings]

Figures 1, 2(a) to 2(d) and 3(a)
) to FIG. 3(d) are diagrams explaining the principle of the method of the present invention, FIG. 4 is a block diagram showing an embodiment of the method of the present invention, and FIG.
It is a block diagram which shows an example of the dressing device of a figure. l... Dressing device 2... Grinding wheel 3...
・Rotary dresser 4... Grinding blade 2a... Outer peripheral surface of grinding wheel 14... AE sensor 21...
Level comparison circuit 22...Time measurement circuit 23 Time comparison circuit

Claims (1)

[Claims] When truing a grinding wheel using a dresser, the acoustic emissions generated during the truing are detected, the duration of the detected acoustic emissions at or above a predetermined level is measured, and the dresser truss the outer peripheral surface of the grinding wheel. A method for determining the flatness of a grinding wheel, characterized in that the integrated value of the duration time width until crossing is determined, and based on this integrated value, it is determined whether or not the grinding wheel has been trued flat.