JP2024053318A - Centerless Grinding Equipment - Google Patents

Abstract

A centerless grinding device capable of further reducing the time and cost required for changeover work is provided.
[Solution] The operations of a first grindstone translation drive mechanism 110, a second grindstone translation drive mechanism 120 and a blade translation drive mechanism 130 are controlled so that the positions of contact points P1, P2 and P3 between the workpiece W and the grinding wheel 11, the regulating wheel 12 and the blade 13, respectively, coincide with the target positions. At this time, the operations of a main guide translation drive mechanism 140, a first auxiliary guide translation drive mechanism 1410 and a second auxiliary guide translation drive mechanism 1420 are controlled so that the position of the workpiece W guided between the grinding wheel 11 and the regulating wheel 12 is adjusted according to the positions of the contact points P1, P2 and P3.
[Selected Figure] Figure 1

Description

This invention relates to technology for automating changeover to workpieces of different diameters in a centerless grinding machine.

The present applicant has proposed a centerless grinding method that enables automation of the changeover work of adjusting the position and/or posture of the grinding wheel, adjusting wheel, and blade depending on the workpiece diameter to be changed over (see Patent Document 1).

Patent No. 5057947

However, in conventional technology, although the relative positions of the grinding wheel and the regulating wheel and the position of the blade are automatically adjusted, the position and/or attitude of the guide plate must be adjusted. This limits the reduction in time and cost required for changeover work.

Therefore, the present invention aims to provide a centerless grinding device that can further reduce the time and cost of changeover work.

The centerless grinding device of the present invention comprises:
A grinding wheel;
Adjusting wheel;
a workpiece guiding mechanism including a pair of guide mechanisms between the grinding wheel and the regulating wheel for guiding the workpiece in the direction of the central axis of the workpiece;
a blade that supports the workpiece from below between the grinding wheel and the regulating wheel;
a wheel translation drive mechanism for relatively translating the grinding wheel and the regulating wheel at least in a horizontal direction;
a main guide translation drive mechanism that translates the work guide mechanism at least in a vertical direction;
an auxiliary guide translation drive mechanism that relatively translates the pair of guide mechanisms at least in a horizontal direction;
and a control device that controls the operation of the grinding wheel translation drive mechanism so as to adjust the positions of the contact points between the grinding wheel, the regulating wheel and the blade and the workpiece in accordance with the outer diameter of the workpiece, and controls the operation of each of the main guide translation drive mechanism and the auxiliary guide translation drive mechanism so as to adjust the position of the workpiece guided between the grinding wheel and the regulating wheel in accordance with the positions of the contact points between the grinding wheel, the regulating wheel and the blade and the workpiece.

In the centerless grinding apparatus having the above configuration,
The grindstone translation drive mechanism includes a first grindstone translation drive mechanism that translates the regulating grindstone at least in a horizontal direction, and a second grindstone translation drive mechanism that translates the grinding grindstone at least in a horizontal direction,
a blade translation drive mechanism that translates the blade at least in a vertical direction;
It is preferable that the control device controls the operation of each of the first grinding wheel translation drive mechanism, the second grinding wheel translation drive mechanism and the blade translation drive mechanism so as to adjust the positions of the contact points between the grinding wheel, the regulating wheel and the blade, respectively, and the workpiece in accordance with the outer diameter of the workpiece.

When changing over to a workpiece of a different diameter in the centerless grinding apparatus having the above configuration,
It is preferable that the control device controls the operation of each of the first grinding wheel translation drive mechanism, the second grinding wheel translation drive mechanism and the blade translation drive mechanism in accordance with the outer diameter of the workpiece so that a first angle, which is an angle formed by a first line segment connecting the center of the workpiece and a first tangent point, which is the tangent point of the workpiece and the blade, with respect to a reference line that passes through the center of the workpiece and extends in the translation direction of the blade, and a second angle, which is an angle formed by a second line segment connecting the center of the workpiece and a second tangent point, which is the tangent point of the workpiece and the adjusting grinding wheel, with respect to the reference line, in a virtual plane perpendicular to the central axis of the workpiece, are constant.
In the centerless grinding apparatus having the above configuration,
It is preferable that the control device controls the operation of each of the main guide translation drive mechanism and the auxiliary guide translation drive mechanism in accordance with the outer diameter of the work so that a third angle, which is an angle formed by a third line segment connecting the center of the work and a third tangent point that is a tangent point between the work and one of the pair of guiding mechanisms, and a fourth angle, which is an angle formed by a fourth line segment connecting the center of the work and a fourth tangent point that is a tangent point between the work and the other of the pair of guiding mechanisms, are constant, with respect to a reference line that passes through the center of the work and extends in the translation direction of the blade, in a virtual plane perpendicular to the central axis of the work.

In the centerless grinding apparatus having the above configuration,
a load sensor for measuring a load acting on the blade;
It is preferable that the control device controls the operation of at least one of the first grindstone translation drive mechanism, the second grindstone translation drive mechanism and the blade translation drive mechanism based on the time-varying behavior of the load acting on the blade while in contact with the workpiece, or a frequency spectrum representing the time-varying behavior of the load, measured using the load sensor, so that the roundness of the workpiece is equal to or greater than a threshold value.

In the centerless grinding apparatus having the above configuration,
It is preferable that the control device controls the operation of at least one of the first grinding wheel translation drive mechanism, the second grinding wheel translation drive mechanism and the blade translation drive mechanism based on designated factors including at least one of the physical property values representing the material of the workpiece, the outer diameter or the outer diameter and the inner diameter, the outer diameter of the grinding wheel, the outer diameter of the regulating wheel, the rotational speed of the grinding wheel, the rotational speed of the regulating wheel, the physical property values representing the material of the grinding wheel, and the physical property values representing the material of the regulating wheel, which are input through an input interface, so that the roundness of the workpiece is equal to or greater than the threshold value.

In the centerless grinding apparatus having the above configuration,
It is preferable that the control device constructs a model through machine learning using a combination of the input results of the specified factors, the measurement results of the positions of the contact points between the grinding wheel, the regulating wheel and the blade and the workpiece, and the measurement results of the roundness of the workpiece as training data, and inputs new input results of the specified factors into the model as input data, thereby outputting as output data target positions of the contact points between the grinding wheel, the regulating wheel and the blade and the workpiece such that the roundness of the workpiece to be newly ground is equal to or greater than the threshold value.

1 is a configuration explanatory diagram of a centerless grinding device according to an embodiment of the present invention; FIG. 2 is an explanatory diagram relating to the configuration of a control device. FIG. 2 is an explanatory diagram regarding the function of the centerless grinding device. FIG. 4 is an explanatory diagram of an operation example of the centerless grinding device.

(composition)
1, a centerless grinding machine according to an embodiment of the present invention includes a grinding wheel 11, a regulating wheel 12, a blade 13, and a workpiece guide mechanism 14. The blade 13 supports the workpiece W from below between the grinding wheel 11 and the regulating wheel 12. The blade 13 is provided with a load sensor S (dynamometer) that outputs a signal according to the load or power acting on the blade 13. The grinding wheel 11, the regulating wheel 12, the blade 13, and the workpiece guide mechanism 14 are provided so as to be displaceable or translatable relative to a bed (not shown) that constitutes the centerless grinding machine and is installed or fixed at an installation location.

In this embodiment, the grinding wheel 11 and the regulating wheel 12 are each configured to be translatable in a first designated direction (x-axis direction in FIG. 1) that is inclined relative to the horizontal direction. The blade 13 and the workpiece guide mechanism 14 are each configured to be translatable in a second designated direction (z-axis direction in FIG. 1) that is perpendicular to the first designated direction and inclined relative to the vertical direction. The regulating wheel 12 may be configured to be translatable in a direction inclined relative to the first designated direction (e.g., the horizontal direction). The horizontal direction may be defined as the first designated direction, and the vertical direction may be defined as the second designated direction.

The workpiece guide mechanism 14 (workpiece feeder) has a first guide mechanism 141 and a second guide mechanism 142 as a pair of roller-type guide mechanisms between the grinding wheel 11 and the adjusting wheel 12 that guide the workpiece W in the direction of the central axis of the workpiece W (the y-axis + direction in Figure 1).

The centerless grinding device shown in FIG. 1 has a first grindstone translation drive mechanism 110, a first grindstone pivot drive mechanism 111, a first grindstone rotation drive mechanism 112, a second grindstone translation drive mechanism 120, a second grindstone pivot drive mechanism 121, a second grindstone rotation drive mechanism 122, a blade translation drive mechanism 130, a main guide translation drive mechanism 140, a first sub-guide translation drive mechanism 1410, and a second sub-guide translation drive mechanism 1420.

The first grinding wheel translation drive mechanism 110 is configured to translate the grinding wheel 11 in a first specified direction. The first grinding wheel swivel drive mechanism 111 is configured to swivel the grinding wheel 11 in a horizontal direction. The first grinding wheel rotation drive mechanism 112 is configured to rotate the grinding wheel 11 around its central axis (axis parallel to the y-axis). The second grinding wheel translation drive mechanism 120 is configured to translate the regulating wheel 12 in a first specified direction. The second grinding wheel swivel drive mechanism 121 is configured to swivel the regulating wheel 12 in a horizontal direction. The second grinding wheel rotation drive mechanism 122 is configured to rotate the regulating wheel 12 around its central axis (axis parallel or approximately parallel to the y-axis).

In this embodiment, the first grindstone translation drive mechanism 110 and the second grindstone translation drive mechanism 120 constitute a "grindstone translation drive mechanism" that relatively translates the grinding wheel 11 and the regulating wheel 12 at least in the horizontal direction (in a first specified direction having a horizontal component). In other embodiments, the "grindstone translation drive mechanism" may be constituted by one of the first grindstone translation drive mechanism 110 and the second grindstone translation drive mechanism 120.

The blade translation drive mechanism 130 is configured to translate the blade 13 at least vertically (in a second specified direction having a vertical component). The blade translation drive mechanism 130 may be omitted. The main guide translation drive mechanism 140 is configured to translate the work guide mechanism 14 in the second specified direction. The first auxiliary guide translation drive mechanism 1410 is configured to translate the first guide mechanism 141 in the first specified direction. The second auxiliary guide translation drive mechanism 1420 is configured to translate the second guide mechanism 142 in the first specified direction.

In this embodiment, the first auxiliary guide translation drive mechanism 1410 and the second auxiliary guide translation drive mechanism 1420 constitute an "auxiliary guide translation drive mechanism" that translates the first guide mechanism 141 and the second guide mechanism 142 relatively at least in the horizontal direction. In other embodiments, the "auxiliary guide translation drive mechanism" may be constituted by one of the first auxiliary guide translation drive mechanism 1410 and the second auxiliary guide translation drive mechanism 1420.

As shown in FIG. 2, the centerless grinding machine includes a control device 200, an input interface 201, and an output interface 202. The control device 200 is configured with an arithmetic processing device (e.g., a CPU, a processor, a processor core) and a storage device (e.g., memories such as ROM and RAM). The control device 200 is configured to execute a task by reading necessary data and a program (software) from the storage device and executing arithmetic processing according to the program on or based on the data.

The control device 200 is configured to control the operation of each of the first grindstone translation drive mechanism 110, the second grindstone translation drive mechanism 120, and the blade translation drive mechanism 130 so as to adjust the positions of contact points P1, P2, and P3 between the grinding wheel 11, the regulating wheel 12, and the blade 13, respectively, and the workpiece W, in accordance with the outer diameter of the workpiece W. The control device 200 is configured to control the operation of each of the main guide translation drive mechanism 140, the first auxiliary guide translation drive mechanism 1410, and the second auxiliary guide translation drive mechanism 1420 so as to adjust the position of the workpiece W guided between the grinding wheel 11 and the regulating wheel 12, in accordance with the positions of the contact points P1, P2, and P3.
Furthermore, the control device 200 is configured to control the operation of each of the first auxiliary guide translation drive mechanism 1410, the second auxiliary guide translation drive mechanism 1420, and the main guide translation drive mechanism 140 so as to adjust the positions of the contact points P4 and P5 between the first guide mechanism 141 and the second guide mechanism 142, respectively, and the workpiece W in accordance with the outer diameter of the workpiece W.

The control device 200 is configured to control the operation of at least one of the first grindstone translation drive mechanism 110, the second grindstone translation drive mechanism 120, and the blade translation drive mechanism 130 to adjust the positions of the contact points P1, P2, and P3 between the grinding wheel 11, the adjusting wheel 12, and the blade 13 and the workpiece W, respectively, based on the output signal of the load sensor S and, in turn, the time-varying state of the load applied to the blade 13 represented by the output signal, so that the roundness of the workpiece W is equal to or greater than a threshold value. Furthermore, the control device 200 is configured to control the operation of the first auxiliary guide translation drive mechanism 1410, the second auxiliary guide translation drive mechanism 1420, and the main guide translation drive mechanism 140, respectively, to adjust the positions of the contact points P4 and P5 between the first guide mechanism 141 and the second guide mechanism 142 and the workpiece W, respectively.

The input interface 201 is configured, for example, with a touch panel display and/or buttons or push keys. The input interface 201 is configured so that designated factors that affect the shape accuracy or roundness of the workpiece W can be input and transmitted to the control device 200 by its operation.

The "designated factors" include at least one of the following: a physical property value representing the material of the workpiece W, the outer diameter (if the workpiece W is cylindrical) or the outer diameter and inner diameter (if the workpiece W is cylindrical), the outer diameter of the grinding wheel 11, the outer diameter of the regulating wheel 12, the rotational speed of the grinding wheel 11, the rotational speed of the regulating wheel 12, a physical property value representing the material of the grinding wheel 11, and a physical property value representing the material of the regulating wheel 12. Among the designated factors, a relatively dynamic first designated factor such as a physical property value representing the material of the workpiece W and the outer diameter (if the workpiece W is cylindrical) or the outer diameter and inner diameter (if the workpiece W is cylindrical) may be input by the operator through the input interface 201. Among the specified factors, relatively static second specified factors such as the outer diameter of the grinding wheel 11, the outer diameter of the regulating wheel 12, the rotational speed of the grinding wheel 11, the rotational speed of the regulating wheel 12, the physical property values representing the material of the grinding wheel 11, and the physical property values representing the material of the regulating wheel 12 may be stored in advance in a storage device constituting the control device 200.

The output interface 202 is configured, for example, by a touch panel display. The output interface 202 is configured to output and display the value of the load measured by the load sensor S, the time-varying state of the load, the frequency spectrum obtained by subjecting the time-varying state of the load to frequency analysis, and/or the roundness of the workpiece W estimated according to the frequency spectrum.

(function)
The function of the centerless grinding machine having the above-described configuration, specifically, the processing procedure executed by the control device 200, will be described with reference to the flowchart shown in FIG.

First, the specified factors such as the outer diameter of the workpiece W are recognized (Figure 3/STEP 102).

Next, the target positions (coordinate values in a virtual plane perpendicular to the central axis O of the workpiece W) of the contact points P1, P2, P3, P4 and P5 of the grinding wheel 11, the adjusting wheel 12, the blade 13, the first guide mechanism 141 and the second guide mechanism 142 with the workpiece W are recognized according to the outer diameter of the workpiece W (FIG. 3/STEP 104). In this process, a reference line is defined in the virtual plane that passes through the center O of the workpiece W and extends in the second specified direction (z-axis direction) that is the translation direction of the blade 13. For example, the target positions of the contact points P1, P2 and P3 are determined so that the first angle, which is the angle formed by the first line segment connecting the center O of the workpiece W and the first contact point P3, which is the contact point between the workpiece W and the blade 13, and the second angle, which is the angle formed by the second line segment connecting the center O of the workpiece W and the second contact point P2, which is the contact point between the workpiece W and the adjusting wheel 12, are constant. Furthermore, the target positions of the contact points P4 and P5 are determined so that the third angle, which is the angle between the third line segment connecting the center O of the work W and the third tangent point P4, which is the tangent point between the work W and the first guide mechanism 141, and the fourth angle, which is the angle between the fourth line segment connecting the center O of the work W and the fourth tangent point P5, which is the tangent point between the work W and the second guide mechanism 142 ... are constant.

Next, the operation of the first grindstone translation drive mechanism 110, the second grindstone translation drive mechanism 120, the blade translation drive mechanism 130, the first sub-guide translation drive mechanism 1410, the second sub-guide translation drive mechanism 1420, and the main guide translation drive mechanism 140 is controlled so that the positions of the contact points P1, P2, P3, P4, and P5 coincide with the target positions.

Then, the workpiece W, which is in contact with the adjusting grindstone 12, which is rotated by the second grindstone rotation drive mechanism 122, is ground (or polished) by the grinding wheel 11, which is rotated by the first grindstone rotation drive mechanism 112 (FIG. 3/STEP 110). At this time, the load applied to the blade 13, and therefore the grinding resistance of the workpiece W, are measured over time based on the output signal of the load sensor S (FIG. 3/STEP 112).

It is determined whether the time-varying behavior of the grinding resistance satisfies a specified condition (FIG. 3/STEP 114). A "specified condition" is a condition that increases the probability that the shape accuracy or roundness of the workpiece will be less than a threshold value. For example, the specified condition may be that the amplitude of the curve representing the time-varying behavior of the grinding resistance exceeds a specified value, and/or that the height of the peak of a specific frequency component in a frequency spectrum obtained by frequency analysis (e.g., FFT) of the time-varying behavior of the grinding resistance exceeds a specified value.

If it is determined that the specified conditions are not met (FIG. 3/STEP 114...NO), it is determined whether grinding of the workpiece W has been completed (FIG. 3/STEP 118).

If it is determined that the specified condition is satisfied (FIG. 3/STEP 114...YES), the operation of at least one of the first grindstone translation drive mechanism 110, the first grindstone pivot drive mechanism 111, the second grindstone translation drive mechanism 120, the second grindstone pivot drive mechanism 121, and the blade translation drive mechanism 130 is controlled so that the positions of the contact points P1, P2, and P3 change (FIG. 3/STEP 116). For example, if the height of the peak of a specific frequency component in the frequency spectrum exceeds a specified value, the positions of the contact points P1, P2, and P3 are feedback-controlled based on the deviation between the height of the peak and the specified value. At this time, the feedback gain may be dynamically determined according to the specified factor.

Then, it is determined whether grinding of the workpiece W has been completed (FIG. 3/STEP 118). For example, if a specified period of time has elapsed since the load on the blade 13 measured by the load sensor S became 0, it is determined that the series of grinding processes for the workpiece W has been completed.

If the result of the determination is negative (FIG. 3/STEP 118...NO), the process for grinding the workpiece W (FIG. 3/STEP 110) and subsequent processes are repeated. If the result of the determination is positive (FIG. 3/STEP 118...YES), the series of processes for the workpiece W to be ground this time is terminated, and the series of processes for the workpiece W to be ground next is started (FIG. 3/STEP 102 and subsequent processes are repeated).

(effect)
According to the centerless grinding device exhibiting the above-mentioned functions, the operations of the first grindstone translation drive mechanism 110, the second grindstone translation drive mechanism 120, and the blade translation drive mechanism 130 are controlled so that the positions of the contact points P1, P2, and P3 between the workpiece W and the grinding wheel 11, the regulating wheel 12, and the blade 13, respectively, coincide with the target positions. At this time, the contact points P4 and P5 are controlled by the operations of the main guide translation drive mechanism 140, the first sub-guide translation drive mechanism 1410, and the second sub-guide translation drive mechanism 1420 so that the position of the workpiece W guided between the grinding wheel 11 and the regulating wheel 12 is adjusted according to the positions of the contact points P1, P2, and P3 (see FIG. 3/STEP 106). This further reduces the time and cost of the changeover work.

Other Embodiments of the Invention
The control device 200 may be configured to construct a model by machine learning using a combination of the input results of the designated factors, the measurement results of the positions of the contact points P1, P2, and P3 between the grinding wheel 11, the regulating wheel 12, and the blade 13 and the workpiece W, and the measurement results of the roundness of the workpiece W as teacher data. Only the first factor may be included in the teacher data, and the model may be constructed for each combination of the second designated factors. Then, the control device 200 may input new input results of the designated factors as input data to the model, and output target positions of the contact points P1, P2, and P3 of the workpiece W such that the roundness of the new workpiece W is equal to or greater than the threshold value as output data. In addition, the target positions of the contact points P4 and P5 of the main guide translation drive mechanism 140, the first sub-guiding translation drive mechanism 1410, and the second sub-guiding translation drive mechanism 1420 may be output as output data.

11: Grinding wheel 12: Adjusting wheel 13: Blade 14: Workpiece guide mechanism 110: First grindstone translation drive mechanism 112: First grindstone rotation drive mechanism 120: Second grindstone translation drive mechanism 122: Second grindstone rotation drive mechanism 130: Blade translation drive mechanism 140: Main guide translation drive mechanism 141: First guide mechanism 142: Second guide mechanism 1410: First sub-guide translation drive mechanism 1420: Second sub-guide translation drive mechanism 200: Control device 201: Input interface 202: Output interface S: Load sensor W: Workpiece.

Claims (7)

A grinding wheel;
Adjusting wheel;
a workpiece guiding mechanism including a pair of guide mechanisms between the grinding wheel and the regulating wheel for guiding the workpiece in the direction of the central axis of the workpiece;
a blade that supports the workpiece from below between the grinding wheel and the regulating wheel;
a wheel translation drive mechanism for relatively translating the grinding wheel and the regulating wheel at least in a horizontal direction;
a main guide translation drive mechanism that translates the work guide mechanism at least in a vertical direction;
an auxiliary guide translation drive mechanism that relatively translates the pair of guide mechanisms at least in a horizontal direction;
a control device that controls operation of the wheel translation drive mechanism so as to adjust positions of contact points between the grinding wheel, the regulating wheel and the blade and the workpiece in accordance with an outer diameter of the workpiece, and that controls operation of each of the main guide translation drive mechanism and the auxiliary guide translation drive mechanism so as to adjust a position of the workpiece guided between the grinding wheel and the regulating wheel in accordance with the positions of contact points between the grinding wheel, the regulating wheel and the blade and the workpiece. 2. The centerless grinding apparatus according to claim 1,
The grindstone translation drive mechanism includes a first grindstone translation drive mechanism that translates the regulating grindstone at least in a horizontal direction, and a second grindstone translation drive mechanism that translates the grinding grindstone at least in a horizontal direction,
a blade translation drive mechanism that translates the blade at least in a vertical direction;
The control device controls the operation of each of the first grinding wheel translation drive mechanism, the second grinding wheel translation drive mechanism, and the blade translation drive mechanism so as to adjust the positions of the contact points between the grinding wheel, the regulating wheel, and the blade, respectively, and the workpiece, in accordance with the outer diameter of the workpiece. 3. The centerless grinding apparatus according to claim 2,
The control device controls the operation of each of the first grinding wheel translation drive mechanism, the second grinding wheel translation drive mechanism and the blade translation drive mechanism in accordance with the outer diameter of the work so that a first angle, which is an angle formed by a first line segment connecting the center of the work and a first tangent point, which is a tangent point between the work and the blade, with respect to a reference line that passes through the center of the work and extends in the translation direction of the blade, and a second angle, which is an angle formed by a second line segment connecting the center of the work and a second tangent point, which is a tangent point between the work and the regulating grinding wheel, with respect to the reference line, in a virtual plane perpendicular to the central axis of the work. 3. The centerless grinding apparatus according to claim 2,
a third angle which is an angle formed by a third line segment connecting the center of the workpiece and a third tangent point which is a tangent point between the workpiece and one of the pair of guide mechanisms, and a fourth angle which is an angle formed by a fourth line segment connecting the center of the workpiece and a fourth tangent point which is a tangent point between the workpiece and the other of the pair of guide mechanisms, in a virtual plane perpendicular to the central axis of the workpiece, with respect to a reference line which passes through the center of the workpiece and extends in the translation direction of the blade, and 4. The centerless grinding apparatus according to claim 2,
a load sensor for measuring a load acting on the blade;
The control device controls the operation of at least one of the first grinding wheel translation drive mechanism, the second grinding wheel translation drive mechanism, and the blade translation drive mechanism based on the time-varying state of the load acting on the blade while in contact with the workpiece, measured using the load sensor, or a frequency spectrum representing the time-varying state of the load, so that the roundness of the workpiece is equal to or greater than a threshold value. 6. The centerless grinding apparatus according to claim 5,
A centerless grinding apparatus in which the control device controls the operation of at least one of the first grinding wheel translation drive mechanism, the second grinding wheel translation drive mechanism, and the blade translation drive mechanism based on designated factors including at least one of the physical property values representing the material of the workpiece, the outer diameter or the outer diameter and the inner diameter, the outer diameter of the grinding wheel, the outer diameter of the regulating wheel, the rotational speed of the grinding wheel, the rotational speed of the regulating wheel, the physical property values representing the material of the grinding wheel, and the physical property values representing the material of the regulating wheel, which are input through an input interface, so that the roundness of the workpiece is equal to or greater than the threshold value. 7. The centerless grinding apparatus according to claim 6,
The control device constructs a model through machine learning using a combination of the input results of the specified factors, the measurement results of the positions of the contact points between the grinding wheel, the regulating wheel, and the blade and the workpiece, and the measurement results of the roundness of the workpiece as training data, and by inputting new input results of the specified factors into the model as input data, the centerless grinding device outputs as output data the target positions of the contact points between the grinding wheel, the regulating wheel, and the blade and the workpiece such that the roundness of the workpiece to be newly ground is equal to or greater than the threshold value.