JPH0561563B2 - - Google Patents

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 in truing a grinding wheel using a dresser.

[Description of Prior Art] As is well known, in grinding wheels, tooling with a dresser is used to flatten the outer circumferential surface of the grinding wheel by eliminating unevenness caused by partial wear of the grinding surface or missing abrasive grains. It is widely practiced. 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 cannot be obtained due to an insufficient depth of cut, but also requires skill and reduces the ease of truing. It was something I lacked.

[Object of the invention] The present invention has been made based on the above viewpoints, and
The purpose of this is to determine whether the grinding wheel has been trued flat or not, and to determine the flatness of the grinding wheel, which is effective in minimizing the depth of cut during truing and contributes to the ease of truing. The purpose is to provide a method.

[Means for Achieving the Object] In the present invention, during truing of a grinding wheel by a dresser, acoustic emissions occurring during the truing are detected, and acoustic emissions of a predetermined level or higher among the detected acoustic emissions are detected.・Measure the duration time width of the emission, calculate the integrated value of the duration time width from the start to the end of the traverse in which the dresser crosses the outer peripheral surface of the grinding wheel, and calculate the integrated value of the duration time width from the time when the dresser crosses the outer peripheral surface of the grinding wheel. depending on whether a predetermined time set based on the traverse speed of the grinding wheel and the grinding wheel width of the grinding wheel has been reached.
The above object is achieved by a method for determining the flatness of a grinding wheel, which comprises determining whether or not the grinding wheel has been trued flat.

In other words, acoustic emission occurs when the abrasive grains of the grinding wheel are crushed, so if there is a concave part on the outer circumferential surface of the grinding wheel that prevents the abrasive grains from being crushed, the acoustic emission will be below a predetermined level. Become. Therefore, since the integrated value of the duration width of the acoustic emission above a predetermined level increases as the concave portion decreases, it is possible to determine whether or not the truing has been flat based on the integrated value. .

[Embodiments of the invention] Fig. 1, Fig. 2 a to Fig. 2 d, and Fig. 3 a to
FIG. 3d is a diagram explaining the principle of the method of the present invention. 1st
The figure shows the relationship between the dressing device and the grinding wheel. FIGS. 2a to 2d show a truing process in which the outer peripheral surface of the grinding wheel is shaped to be flat. Figures 3a to 3d show the acoustic emission levels generated in the steps of Figures 2a to 2d, where the horizontal axis is time, P _S is the traverse start point, and P _E is the traverse start point. This is the 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 set diagonally with respect to the grinding wheel 2 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. Dressing device 1
can move in the direction of arrow A-B in the figure,
By moving in the direction, the grinding blade 4 touches the outer peripheral surface 2 of the grinding wheel 2.
It is designed to come into contact with a. The grinding wheel 2 is
It is rotationally driven by the shaft 5 and is rotated by the arrow C- in the diagram.
Movement in the D direction is possible, and this movement causes the rotary dresser 3 to cross the outer circumferential 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 1 is moved in the direction A, the grinding blade 4 connects to the outer circumferential surface 2a of the grinding wheel 2, thereby removing the abrasive grains on the outer circumferential surface 2a. is crushed and acoustic emission (hereinafter referred to as AE)
occurs. Upon detection of AE, dressing device 1
The movement of the grinding wheel 2 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. 2a, a concave portion 6a,
6b and 6c exist, and when traversing, the concave portion 6
Assuming that the abrasive grains a to 6c are not crushed,
As shown in FIG. 3a, the AE is at a low level in the concave portions 6a to 6c where the abrasive grains are not crushed, and is at a high level in other portions. The movements of the dressing device 1 and the grinding wheel 2 are controlled as described above, and the
When the abrasive grains in the concave portion 6b are crushed as shown in FIG. 2b during the second traverse, the time width of the high level portion of AE increases as shown in FIG. 3b. When the abrasive grains in the concave portion 6a are crushed in the third traverse as shown in FIG. 2c, the time width of the high level portion of AE further increases as shown in FIG. 3c. Assuming that in the fourth traverse, the abrasive grains in the last concave portion 6c are crushed and the outer circumferential surface 2a of the grinding wheel 2 becomes flat as shown in FIG. 2d, the traverse start point is as shown in FIG. 3d. A high level of AE occurs from P _S to the traverse end point P _E.

Therefore, by detecting that a high level of AE has occurred from the traverse start point P _S to the traverse end point P _E , it is determined that the outer circumferential surface 2a of the grinding wheel 2 has been trued flat. be able to.

FIG. 4 is a block diagram showing an embodiment of the method of the present invention, and FIG. 5 is a block diagram showing an example of the dressing device 1 of FIG. 1.

The dressing device configured as shown in FIG. ing. The shaft 10 is easily rotated by the housing 12 via the bearing 11, and the drive shaft 1
3. Inside the housing 12, an AE sensor 14 is provided, and a cutting fluid ejection passage 15 is formed. The AE sensor 14 is housed in a through hole 16 formed parallel to the shaft 10, and the wave receiving surface is placed in close contact with the inner surface of a screw plug 17a that closes the open end of the through hole 16 facing the rotary dresser 3. It is arranged and fixed by a spacer 17b and another screw plug 17c. Cutting fluid spout passage 1
5 is formed in parallel with the shaft 10 and the through hole 16, and has a spout 1 on the rotary dresser 3 side.
5a, and the other end is connected to the cutting fluid introduction pipe 18. A cutting fluid introduction pipe 1 is provided in the cutting fluid jetting passage 15.
High-pressure cutting fluid is applied through the spout 15
Cutting fluid is spouted from a toward the rotary dresser 3. Grinding wheel 2 (Fig. 1)
The AE generated when the abrasive grains are crushed is received by the AE sensor 14 through the rotary dresser → 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. It's becoming like that.

In FIG. 4, 20 is an input circuit which inputs the AE signal output from the AE sensor 14, performs processing such as noise removal and amplification, and then supplies the AE signal to the level comparison circuit 21. Level comparison circuit 2
1 provides an H level output for an AE 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 Figure 3b. 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 calculates the integrated value T of the duration of the duration from the start to the end of the traverse. is calculated, and this integrated value T is given to the time comparator circuit 23. The integrated value T is at the start of the traverse in Figures 3a to 3d.
High level AE from P _S to traverse end point P _E
corresponds to the integrated value of the time width. Time comparison circuit 23
compares the integrated value T given from the time measuring circuit 22 and _T0 at a predetermined time, and if the integrated value T is determined at a predetermined time
When T ₀ is reached, a truing completion signal is given to the control device 24. The predetermined time T ₀ is selected based on the speed V (traverse speed) at which the rotary dresser 3 crosses the outer circumferential surface 2 a of the grinding wheel 2 and the grinding wheel width W of the grinding wheel 2 so that T ₀ ≈W/V. The control device 24 inputs the AE signal of the AE sensor 14 through the level comparison circuit 21, controls the rotation and movement of the dressing device 1 and the grinding wheel 2 as described in FIG. 1, and also outputs a traverse start signal and a traverse end signal. The signal is given to the time measurement circuit 22, and further, upon receiving a truing completion signal from the time comparison circuit 23, truing completion control such as displaying truing completion is performed. The traverse start signal is given in synchronization with the start of movement of the grinding wheel 2 for traverse, and the traverse 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, as shown in FIGS. 2a to 2c, the outer peripheral surface 2a of the grinding wheel 2
If a concave portion exists in the concave portion, the level of the AE signal becomes lower than the reference level in the concave portion, so the integrated value T becomes smaller than the predetermined time _T0 , and a truing completion signal is not given. On the other hand, when the outer circumferential surface 2a of the grinding wheel 2 has no concave portions and becomes flat as shown in FIG. , the integrated value T reaches the predetermined time T ₀ ,
A truing completion signal indicating that flat truing has been achieved will be given.

In the embodiment described above, the rotary dresser has AE
Although we have described the case where a sensor is installed, it is of course possible to use a non-rotating type dresser such as a single stone diamond dresser, and if it is a non-rotating type, AE can be received directly from the dresser.
An AE sensor can be provided.

[Effects of the Invention] As explained above, according to the present invention, attention is paid to the fact that the level of acoustic emission that occurs when the abrasive grains of a grinding wheel are crushed changes depending on the evaluation state of the grinding wheel, and Accumulate the acoustic emission and duration width of
Since we decided to determine whether or not the truing was done flatly based on this integrated value, it is possible to easily know whether the truing was done flatly or not, and moreover, it is possible to truing flatly with the minimum necessary cut. It is possible to provide a method for determining the flatness of a grinding wheel that not only achieves the following effects, but also contributes to automation of the grinding process.

[Brief explanation of the drawing]

Figures 1, 2a-2d and 3a-
FIG. 3d is a diagram illustrating the principle of the method of the present invention, FIG. 4 is a block diagram showing an embodiment of the method, and FIG. 5 is a block diagram showing an example of the dressing apparatus of FIG. 1. 1... 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] 1. In the truing of a grinding wheel by a dresser, the acoustic emission occurring during the truing is detected, and the duration of the acoustic emission of a predetermined level or higher among the detected acoustic emissions is measured, and the dresser is An integrated value of the continuous width from the start to the end of the traverse across the outer peripheral surface of the grinding wheel is determined, and the integrated value of the continuous time width is based on the traverse speed of the dresser and the grinding wheel width of the grinding wheel. A method for determining flatness of a grinding wheel, characterized in that it is determined whether or not the grinding wheel has been trued flat depending on whether or not a set predetermined time has been reached.