WO2013002371A1

WO2013002371A1 - Superfinishing method and superfinishing device

Info

Publication number: WO2013002371A1
Application number: PCT/JP2012/066700
Authority: WO
Inventors: 大橋　一仁; 孝大西; 眞也塚本; 晃平東
Original assignee: Ntn株式会社
Priority date: 2011-06-29
Filing date: 2012-06-29
Publication date: 2013-01-03
Also published as: JP5926137B2; JP2013031915A

Abstract

Provided is a superfinishing method and superfinishing device with which stable processing conditions can be obtained. The grinding wheel head (4) of a superfinishing device in which a grindstone (10) supported on the grinding wheel head (4) is pressed, while oscillating, against a rotating workpiece (9) is provided with: a cutting force component sensor (6a) that detects a force component (Q) in a direction tangential to the rotating workpiece (9); a thrust force component sensor (6b) that detects a force component (P) in the direction of pressure; an oscillation load sensor (6c) that detects a force component (R) in the direction of grindstone (10) oscillation; a movement sensor (7) that detects the amount of movement in the direction in which the grindstone (10) is pressed; and an in-process gauge (8) that detects the size reduction of the workpiece (9). Processing conditions are assessed based on the output of the sensors (6a, 6b), which change as a result of "coarse finishing" → "superfinishing", and processing efficiency is improved by changing processing conditions (rotation rate, oscillation rate, pressing force).

Description

Superfinishing method and superfinishing machine

The present invention relates to a superfinishing processing method and a superfinishing processing apparatus.

In general, mirror finishing of industrial parts typified by bearings having raceway surfaces employs super-finishing processing in which grinding is performed by pressing a grindstone against a rotating workpiece while rocking.
In the super-finishing process, as represented by Patent Document 1, first, a “rough” process is performed in which abrasive grains are dropped to increase the grinding efficiency, and then the grindstone is clogged to generate a mirror surface. "Finish" processing. Switching from “rough” machining to “finishing” machining is done by lowering the rocking speed of the grindstone without changing the rotation speed of the workpiece, and the switching timing is generally determined by timer control. is there.

Also, as a superfinishing method using a technique other than the timer control, there is a method using a force sensor described in Patent Document 2. This is because the end face in the axial direction of the annular workpiece is supported by a backing plate that rotates integrally with the spindle of the superfinishing machine, and at the same time the inner or outer peripheral surface of the annular workpiece is supported by a shoe. A force sensor for detecting the force applied to the shoe from the object is provided, and the processing state of the grindstone is determined based on the detection output of the force sensor. Based on this determination, the switching timing from the “rough” machining to the “finishing” machining and the end timing of the “finishing” machining are determined.

JP-A-6-79616 JP 2004-114279 A

However, in the processing method of Patent Document 1, the time from the start of “rough” processing to the switching to “finishing” processing is set in advance by a timer. For this reason, there are problems that sufficient processing accuracy cannot be obtained and processing efficiency is lowered. In other words, the machining time for “rough” machining is constant regardless of the surface roughness of the workpiece before machining, so depending on the surface roughness of the workpiece before machining, The surface roughness of the object does not reach the target surface roughness, and as a result, there is a possibility that sufficient processing accuracy cannot be obtained when the “finishing” processing is completed. Therefore, in order to ensure sufficient machining accuracy, it may be possible to lengthen the machining time for the “rough” machining set by the timer. However, if this is done, the machining time for the “rough” machining will be longer than necessary and the machining efficiency will be increased. Decreases.

In addition, when the grindstone is in an extremely clogged state (adhesion state) due to some trouble, there has been no means to detect the extremely clogged state, so that sufficient machining allowance can be obtained for subsequent processing. There was a risk of defective products.

On the other hand, in the method of Patent Document 2, the state of the grindstone is determined based on the detection output of the force sensor, and the switching timing from “rough” processing to “finishing” processing is determined based on the determination. However, in the method of Patent Document 2, the workpiece is supported by the backing plate and the shoe, and only the supporting force by the shoe is detected by the force sensor among the supporting force by the backing plate and the supporting force by the shoe. The detection output is likely to be unstable due to the influence of the support force by the backing plate. Therefore, it is difficult to stably determine the state of the grindstone, and there is a possibility that the switching timing from the “rough” processing to the “finishing” processing becomes unstable. In particular, when the grindstone to be used is a superabrasive grindstone, the processing efficiency is high and the machining resistance is small compared to general abrasive grindstones represented by alumina and silicon carbide, so the state of the grindstone has changed. When the force changes little. Therefore, it is difficult to stably determine the state of the grindstone.
Moreover, the method using the force sensor of patent document 2 is a method limited only to the bearing ring of a ball bearing.

Therefore, an object of the present invention is to provide a superfinishing method and a superfinishing device that can obtain a stable machining state.

In order to solve the above-described problems, in the present invention, a workpiece is rotated, and the workpiece is pressed against the workpiece while the grindstone is swung in a direction perpendicular to the tangential direction of the rotation of the workpiece. A main component force sensor for detecting a component force Q in a tangential direction of rotation of the workpiece of the force applied to the grindstone in a state of being pressed against the workpiece on the grindstone table that supports the grindstone. A back component force sensor for detecting a component force P in the pressing direction of the grindstone of the force applied to the grindstone in a state of being pressed against the workpiece, and based on the component forces P and Q detected by each sensor The method of determining the machining state of the workpiece was adopted.

In this way, the tangential component force Q detected by the main component force sensor during the superfinishing process changes the machining resistance between the grindstone and the work piece according to the grindstone machining state. It exhibits a reaction according to the processing state of the grindstone.
For example, when “rough” processing is performed, the processing state of the grindstone is a state (cutting state) in which the blades are positively spontaneously generated by dropping off the abrasive grains. Thereafter, when shifting to the “finishing” process, the processing state of the grindstone shifts to a clogged state (polished state) through a semi-cut state. During this time, since the component force P in the pressing direction is determined by the pressing force against the grindstone, when the pressing force is set to be constant, a substantially constant value is indicated accordingly. Here, normally, the component force (back component force) P in the pressing direction is a gutter that indicates a value corresponding to the grinding stone pressing force. However, the tangential component force (main component force) Q generally has a characteristic of maintaining a constant ratio with respect to the back component force P according to the processing. Therefore, if the surface condition or the machining state of the grindstone does not change under the machining conditions, the machining component force ratio P / Q shows a constant value even if the pressing force is changed. Therefore, when the pressing force is set to be constant, the component force P shows a substantially constant value accordingly. On the other hand, the component force Q in the tangential direction shows a change according to the processing state of the grindstone. Specifically, when “rough” machining is performed, the grindstone is self-generated, increasing the machining resistance, and the tangential component force Q takes a large value. Thereafter, when the process shifts to “finishing”, the self-generated blade is stopped and the grindstone is in a polished state, so that the machining resistance is reduced and the main component force Q is a small value. Therefore, if this is monitored, the processing state of the grindstone during the “rough” processing and “finishing” processing can be determined.

At this time, the grindstone table is provided with an air cylinder that presses the grindstone supported on the tip by advancing the rod against the workpiece, and the main wheel is disposed between the tip of the rod of the air cylinder to which the grindstone is attached and the grindstone. A component force sensor and the back component force sensor can be arranged.

In this case, since the force applied to the grindstone is detected instead of detecting the force applied to the member that supports the workpiece, the processing state of the grindstone can be determined regardless of the method of supporting the workpiece. Therefore, the range of application of workpieces is wide.

Further, an in-process gauge for detecting a reduction in the size of the workpiece caused by processing with a grindstone, and a movement amount sensor for detecting a movement amount in the pressing direction of the grindstone due to a reduction in the size of the workpiece and wear of the grindstone. And adopting a method of determining the machining state of the workpiece based on the dimension reduction amount of the workpiece detected by the in-process gauge and the movement amount of the grindstone detected by the movement amount sensor. Can do.

In this way, when performing “rough” processing, the processing state of the grindstone becomes a state (cutting state) in which the blades are positively spontaneously generated by the removal of the abrasive grains. Therefore, the movement amount detected by the movement amount sensor increases (advances) at a constant speed, and the reduction amount of the finishing dimension detected by the in-process gauge decreases at a constant rate. On the other hand, when shifting to “finishing” processing, the processing state of the grindstone shifts to a clogged state (polished state) through a semi-cut state. For this reason, the movement amount detected by the movement amount sensor is constant, and the change in the finishing dimension detected by the in-process gauge is stagnant. As described above, since the dimension reduction amount detected by the in-process gauge and the movement amount detected by the movement amount sensor exhibit different characteristics, it is possible to discriminate between “rough” processing and “finishing” processing. Therefore, by combining the output characteristics of the movement amount sensor and the in-process gauge with the detection outputs of the main component force sensor and the back component force sensor, it is possible to improve the discrimination accuracy for switching from “rough” to “finish” processing.

Further, in the present invention, the workpiece is rotated, and the grinding stone is pressed against the workpiece while swinging the grinding stone in a direction perpendicular to the tangential direction of the rotation of the workpiece, thereby super-finishing the workpiece. A main component force sensor for detecting a component force Q in a tangential direction of rotation of the workpiece applied to the grindstone in a state of being pressed against the workpiece on the grindstone table that supports the grindstone; A back component force sensor that detects a component force P in the pressing direction of the grindstone of the force applied to the grindstone in the applied state, and the superfinishing processing based on the component forces P and Q detected by each sensor The method of performing the control is adopted.

By adopting such a method, it is possible to obtain a stable machining state by changing machining conditions in accordance with changes in the component forces P and Q detected by the main component force sensor and the back component force sensor. Become.
That is, as described above, during super finishing, the component force P in the pressing direction shows a substantially constant value. On the other hand, the component force Q in the tangential direction has a large machining resistance when the “rough” machining is performed, and the component force Q takes a large value. Thereafter, when the process shifts to “finishing”, the self-generated blade stops and the machining resistance decreases, so the main component force Q becomes a small value. Therefore, it is possible to determine the processing state of the grindstone during the “rough” machining and the “finishing” machining by monitoring this, and based on the judgment, the rotational speed of the workpiece, the rocking of the grindstone By controlling the processing conditions such as the number and the pressing force of the grindstone, a stable processing state can be obtained. Further, by using the determination method, it is possible to control the superfinishing process even in a process other than using a shoe or a process using a superabrasive grindstone. Furthermore, if an abnormality is detected from the determination, a grindstone defect can also be detected.

At this time, the grindstone table is provided with an air cylinder for pressing the grindstone supported at the tip by advancing the rod against the workpiece, and the main wheel is disposed between the tip of the rod of the air cylinder to which the grindstone is attached and the grindstone. A component force sensor and the back component force sensor can be arranged.

In this way, the force applied to the grindstone can be detected, and the processing state of the grindstone can be determined regardless of the workpiece support method. Therefore, based on the determination, it is possible to obtain a more stable machining state by changing machining conditions such as the number of rotations of the workpiece, the rocking speed of the grindstone, and the pressing force of the grindstone.

At this time, as the control of the superfinishing process performed based on the respective component forces P and Q, the ratio P / of the component force P detected by the back component force sensor with respect to the component force Q detected by the main component force sensor. Processing conditions so that the ratio of the rocking speed of the grindstone to the rotational speed of the workpiece is increased when Q is sequentially calculated and the ratio P / Q is larger than a preset upper limit value. It is possible to adopt a control that changes.

In this way, during the superfinishing process, the main component force Q is reduced when the machining resistance is reduced due to a lack of self-generated blades of the grindstone, and as a result, the ratio P / Q is large. Becomes larger than a preset upper limit value. At this time, the ratio of the rocking speed of the grindstone to the rotational speed of the workpiece is increased, that is, the maximum intersection formed by the trajectory of the abrasive grain generated on the workpiece surface and the traveling direction of the workpiece surface. Since the control for changing the machining conditions so as to increase the angle is executed, the self-generated blade of the grindstone is promoted, and the deterioration of the processing accuracy due to the lack of the self-generated blade of the grindstone can be prevented.

Further, as the super finishing process control based on the respective component forces P and Q, the ratio P / Q of the component force P detected by the back component force sensor with respect to the component force Q detected by the main component force sensor. Are sequentially calculated, and when the magnitude of the ratio P / Q becomes smaller than a preset lower limit value, the machining conditions are set so that the ratio of the rocking speed of the grindstone to the rotational speed of the workpiece becomes small. Variable control can be employed.

In this way, during the superfinishing process, when the machining resistance increases due to excessive self-generated blades of the grindstone, the main component force Q increases, and as a result, the ratio P / Q increases. Becomes smaller than a preset lower limit value. At this time, the ratio of the rocking speed of the grindstone to the rotational speed of the workpiece is reduced, that is, the maximum intersection formed by the locus of the abrasive grains generated on the workpiece surface and the traveling direction of the workpiece surface. Since control is performed to change the machining conditions so as to reduce the angle, the self-generated blade of the grindstone is suppressed, and due to the excessive self-generated blade of the grindstone, the ratio of the amount of wear of the grindstone to the amount of reduction in the size of the workpiece A reduction in the superfinishing ratio can be prevented.

Further, as the super finishing process control based on the respective component forces P and Q, the ratio P / Q of the component force P detected by the back component force sensor with respect to the component force Q detected by the main component force sensor. Is calculated, and when the ratio P / Q becomes larger than a preset upper limit value, control is performed to change the machining conditions so as to increase the pressing force of the grindstone against the workpiece. Can do.

In this way, during the superfinishing process, the main component force Q is reduced when the machining resistance is reduced due to a lack of self-generated blades of the grindstone, and as a result, the ratio P / Q is large. Becomes larger than a preset upper limit value. At this time, since control is performed to change the processing conditions so as to increase the pressing force of the grindstone against the workpiece, the self-generated blade of the grindstone is promoted, and the deterioration of the processing accuracy due to the lack of the self-generated blade of the grindstone is prevented. Can do.

Further, as the super finishing process control based on the respective component forces P and Q, the ratio P / Q of the component force P detected by the back component force sensor with respect to the component force Q detected by the main component force sensor. Is calculated, and when the magnitude of the ratio P / Q becomes smaller than a preset lower limit, a control is adopted that changes the machining conditions so as to reduce the pressing force of the grindstone against the workpiece. Can do.

In this way, during the superfinishing process, when the machining resistance increases due to excessive self-generated blades of the grindstone, the main component force Q increases, and as a result, the ratio P / Q increases. Becomes smaller than a preset lower limit value. At this time, since control is performed to change the processing conditions so as to reduce the pressing force of the grindstone against the workpiece, the self-generated blade of the grindstone is suppressed, and the reduction of the superfinishing ratio due to excessive self-generated blade of the grindstone is prevented. be able to.

Further, as the super finishing process control based on the respective component forces P and Q, the ratio P / Q of the component force P detected by the back component force sensor with respect to the component force Q detected by the main component force sensor. Is calculated successively, and when the magnitude of the ratio P / Q becomes larger than a preset abnormality detection threshold, it is possible to adopt a control for determining that the clogged stone is extremely clogged. it can.

In this way, during the superfinishing process, when the machining resistance becomes too small due to the extreme clogging of the grindstone, the main component force Q becomes too small. As a result, the ratio P Since the magnitude of / Q becomes larger than a preset abnormality detection threshold value, control is performed to determine that extreme clogging has occurred in the grindstone. As a result, it is possible to detect the abnormality of the grindstone at an early stage, and it is possible to prevent the occurrence of defective products due to clogging of the grindstone.

Further, an in-process gauge for detecting a reduction in the size of the workpiece due to machining with a grindstone, and a movement amount sensor for detecting a movement amount in the pressing direction of the grindstone due to a reduction in the size of the workpiece and wear of the grindstone And the superfinishing ratio can be calculated based on the dimensional reduction amount of the workpiece detected by the in-process gauge and the movement amount of the grindstone detected by the movement amount sensor.

In this way, it is possible to know in real time the superfinishing ratio at each point in time when superfinishing is being performed. As a result, in order to improve the superfinishing ratio, It becomes easy to grasp at which point the processing conditions should be adjusted. The superfinishing ratio is the ratio of the amount of wear of the grindstone to the amount of reduction in the size of the workpiece, and greatly affects the machining cost.

In addition, a rocking load sensor for detecting a component force R in the rocking direction of the grindstone of the force applied to the grindstone pressed against the workpiece is further provided on the grindstone table that supports the grindstone, and the rocking load is provided. The superfinishing process can be controlled based on the amplitude of the component force R detected by the sensor.

In this case, the magnitude of the component force R in the oscillating direction detected by the oscillating load sensor depends on the inertial force of the oscillating grindstone and the machining resistance acting between the grindstone and the workpiece, It exhibits sine wave vibration according to the rocking number of the grindstone. Here, when the processing state of the grindstone is a state (cutting state) in which the abrasive grains are positively generated spontaneously by cutting off the abrasive grains, the processing resistance is increased because the grindstone is spontaneously bladed, and the component force in the oscillating direction The amplitude of R increases. On the other hand, when the processing state of the grindstone is a polished state in which the self-generated blade is stopped, the processing resistance decreases and the amplitude of the component force R in the swinging direction decreases. Therefore, if the amplitude of the component force R in the swinging direction is monitored, it is possible to determine the machining state when performing “rough” machining and “finishing” machining, and based on this judgment, the rotational speed of the workpiece By changing the processing conditions such as the rocking number of the grindstone and the pressing force of the grindstone, a stable processing state can be obtained.

At this time, as the control of the super finishing performed based on the magnitude of the amplitude of the component force R, the magnitude of the amplitude of the component force R detected by the swing load sensor is larger than a preset lower limit width. In this case, it is possible to adopt a control for changing the machining condition so that the ratio of the rocking speed of the grindstone to the rotational speed of the workpiece increases.

In this way, the amplitude of the component force R is smaller than the preset lower limit width when the machining resistance is reduced due to the lack of the self-generated blade of the grindstone during superfinishing. Get smaller. At this time, the ratio of the rocking speed of the grindstone to the rotational speed of the workpiece is increased, that is, the maximum crossing angle formed by the abrasive locus generated on the workpiece surface and the traveling direction of the workpiece surface. Since the control to change the machining conditions is executed so that the grinding wheel becomes large, the self-generated blade of the grindstone is promoted, and the deterioration of the machining accuracy due to the lack of the self-generated blade of the grindstone can be prevented.

Further, as the control of the superfinishing process performed based on the magnitude of the amplitude of the component force R, the magnitude of the amplitude of the component force R detected by the swing load sensor is larger than a preset upper limit width. Control that changes the machining conditions so that the ratio of the rocking speed of the grindstone to the rotational speed of the workpiece becomes small when it becomes large can be employed.

In this way, during the superfinishing process, when the machining resistance increases due to excessive self-generated blades of the grindstone, the amplitude of the component force R is larger than the preset upper limit width. growing. At this time, the ratio of the rocking speed of the grindstone to the rotational speed of the workpiece is reduced, that is, the maximum crossing angle formed by the abrasive locus generated on the workpiece surface and the traveling direction of the workpiece surface. Since the control is performed to change the machining conditions so as to decrease, the self-generated blade of the grindstone is suppressed, and the reduction of the superfinishing ratio due to the excessive self-generated blade of the grindstone can be prevented.

In addition, as the super finishing process control based on the amplitude of the component force R, the amplitude of the component force R detected by the swing load sensor is smaller than a preset lower limit width. When it becomes smaller, it is possible to adopt a control for changing the machining conditions so as to increase the pressing force of the grindstone against the workpiece.

In this way, the amplitude of the component force R is smaller than the preset lower limit width when the machining resistance is reduced due to the lack of the self-generated blade of the grindstone during superfinishing. Get smaller. At this time, since control is performed to change the processing conditions so as to increase the pressing force of the grindstone against the workpiece, the self-generated blade of the grindstone is promoted, and the deterioration of the processing accuracy due to the lack of the self-generated blade of the grindstone is prevented. Can do.

Further, as the control of the superfinishing process performed based on the magnitude of the amplitude of the component force R, the magnitude of the amplitude of the component force R detected by the swing load sensor is larger than a preset upper limit width. When it becomes larger, it is possible to adopt control for changing the machining conditions so as to reduce the pressing force of the grindstone against the workpiece.

In this way, during the superfinishing process, when the machining resistance increases due to excessive self-generated blades of the grindstone, the amplitude of the component force R is larger than the preset upper limit width. growing. At this time, since control is performed to change the processing conditions so as to reduce the pressing force of the grindstone against the workpiece, the self-generated blade of the grindstone is suppressed, and the reduction of the superfinishing ratio due to excessive self-generated blade of the grindstone is prevented. be able to.

As the coolant supplied between the workpiece and the grindstone when superfinishing is performed, a water-insoluble (oil-based) coolant excellent in lubricity and permeability is generally employed. , Even if water-soluble coolant with poor lubricity and permeability is used, it is possible to control the self-generated blade of the grindstone based on the detection signal of each sensor, so that a stable machining state can be obtained. Is possible.

Examples of the workpiece include an inner ring, an outer ring, and a rolling element of a bearing.

Further, in the present application, as the super-finishing processing apparatus for performing the super-finishing processing method, the workpiece is rotated while the grindstone is swung in a direction perpendicular to the tangential direction of the rotation of the workpiece. A superfinishing machine that presses the grindstone against the workpiece and superfinishing the workpiece, and a grinder mounted on the grindstone table that supports the grindstone, and the rotation of the workpiece with the force applied to the grindstone pressed against the workpiece A main component sensor for detecting a component force Q in the tangential direction, and a component force P in the pressing direction of the grindstone applied to the grindstone that is attached to the grindstone table that supports the grindstone and is pressed against the workpiece. And a control device that controls the superfinishing process based on the component forces P and Q detected by the sensors.

At this time, the grindstone table includes an air cylinder that presses the grindstone supported at the tip by advancing the rod against the workpiece, and a main component force sensor between the tip of the rod of the air cylinder to which the grindstone is attached and the grindstone It can be set as the structure which provided the back component force sensor.

The control device sequentially calculates a ratio P / Q of the component force P detected by the back component force sensor to the component force Q detected by the main component force sensor, and the magnitude of the ratio P / Q is preset. When the upper limit value is exceeded, control can be performed to change the machining conditions so that the ratio of the rocking speed of the grindstone to the rotational speed of the workpiece is increased.

The control device sequentially calculates a ratio P / Q of the component force P detected by the back component force sensor with respect to the component force Q detected by the main component force sensor, and the magnitude of the ratio P / Q is determined in advance. When it becomes smaller than the set lower limit value, it is possible to perform a control for changing the machining conditions so that the ratio of the rocking number of the grindstone to the rotation speed of the workpiece becomes small.

The control device sequentially calculates a ratio P / Q of the component force P detected by the back component force sensor with respect to the component force Q detected by the main component force sensor, and the magnitude of the ratio P / Q is determined in advance. When it becomes larger than the set upper limit value, it is possible to perform a control for changing the machining conditions so as to increase the pressing force of the grindstone against the workpiece.

The control device sequentially calculates a ratio P / Q of the component force P detected by the back component force sensor with respect to the component force Q detected by the main component force sensor, and the magnitude of the ratio P / Q is determined in advance. When it becomes smaller than the set lower limit value, it is possible to perform a control for changing the machining conditions so as to reduce the pressing force of the grindstone against the workpiece.

Further, an in-process gauge for detecting a reduction in the size of the workpiece caused by processing with a grindstone, and a movement amount sensor for detecting a movement amount in the pressing direction of the grindstone due to a reduction in the size of the workpiece and wear of the grindstone. And the control device reduces the dimension of the workpiece based on the dimension reduction amount of the workpiece detected by the in-process gauge and the movement amount of the grindstone detected by the movement amount sensor. A configuration in which a superfinishing ratio, which is a ratio of the wear amount of the grindstone to the amount, can be employed. The control device further includes a rocking load sensor for detecting a component force R in the rocking direction of the grindstone of the force applied to the grindstone pressed against the workpiece on the grindstone table that supports the grindstone. May employ a configuration in which the superfinishing process is controlled based on the amplitude of the component force R detected by the swing load sensor.

Further, a configuration having a discharge nozzle for supplying water-soluble coolant between the workpiece and the grindstone can be adopted.

The superfinishing processing method and superfinishing processing device of the present invention are based on the component forces P and Q detected by the main component force sensor and the back component force sensor, and the rotational speed of the workpiece, the rocking number of the grindstone, By changing processing conditions such as pressing force, it is possible to obtain a stable processing state.

Schematic diagram of the embodiment Block diagram of the embodiment (A), (b) Action explanatory drawing of embodiment Action explanatory diagram of the embodiment Action explanatory diagram of the embodiment Action explanatory diagram of the embodiment Action explanatory diagram of the embodiment Action explanatory diagram of the embodiment Action explanatory diagram of the embodiment (A), (b) Schematic diagram of Example 2 (A)-(d) Action explanatory drawing of Example 3

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
1 and 2 are schematic views of a superfinishing apparatus for explaining the present invention. FIG. 1 is a schematic diagram of the superfinishing machine, and FIG. 2 is a block diagram of the control device 19.

The superfinishing apparatus includes a superfinishing machine and a control device 19.
As shown in FIG. 1, the superfinishing machine includes a fixed center 1, a turner 2, a swing device 3, a grinding wheel base 4, an air cylinder 5, a main component force sensor 6a, a back component force sensor 6b, and a swing load sensor 6c. , A movement amount sensor 7, an in-process gauge 8, a grindstone 10, and a discharge nozzle 12.

The workpiece 9 supported by the fixed center 1 of the superfinishing machine is given a rotational force by the turner 2. A grindstone base 4 that supports the grindstone 10 is attached to the rocking device 3. The oscillating device 3 applies a driving force for reciprocating the grindstone table 4. A main component force sensor 6a, a back component force sensor 6b, and a swing load sensor 6c are attached to a grindstone table 4 that is swung by the swing device 3 via an air cylinder 5, and the main component force sensor 6a, The grindstone 10 is supported by the component force sensor 6b and the swing load sensor 6c. Specifically, the main component force sensor 6a, the back component force sensor 6b, and the swing load sensor 6c are provided between the tip of the rod 13 of the air cylinder 5 to which the grindstone 10 is attached and the grindstone 10.
Here, the main component force sensor 6a detects the component force Q in the tangential direction of the rotation of the workpiece 9 out of the force applied to the grindstone 10 pressed against the workpiece 9.
The back component force sensor 6b detects the component force P in the pressing direction of the grindstone 10 out of the force applied to the grindstone 10 pressed against the workpiece 9.
The rocking load sensor 6 c detects a component force R in the rocking direction of the grindstone 10 out of the force applied to the grindstone 10 pressed against the workpiece 9.
As these main component force sensor 6a, back component force sensor 6b, and swing load sensor 6c, for example, a force sensor such as a load cell, a piezoelectric element (semiconductor (piezoresistive element) strain gauge, unimorph, bimorph) or the like can be used. . These

sensors

6a, 6b, and 6c can be provided as separate sensors, respectively, but may be an integrated three-axis type. In this embodiment, an integral unit is used.

Further, a movement amount sensor 7 is attached to the rear end of the air cylinder 5 to detect the movement amount S of the grindstone 10. In this case, as the movement amount sensor 7, for example, a potentiometer can be used.
In addition to such a potentiometer, a non-contact type linear motion displacement meter using an optical type or a differential transformer may be used aiming at a drip-proof effect from a coolant which is a liquid.
The in-process gauge 8 is for detecting a dimensional change of the workpiece 9 during processing, and is arranged so that the stylus comes into contact with the workpiece 9 and measures the size of the workpiece 9 simultaneously with the processing. It is like that. By doing so, the superfinishing ratio U can be obtained from the finishing dimension reduction amount T and the movement amount S of the grindstone 10 described later.
The coolant 11 has the performance of reducing the frictional force between the grindstone 10 and the workpiece 9 (lubricating action), discharging chips (cleaning action), and discharging processing heat (cooling action). And the coolant 11 arrange | positions the discharge nozzle 12 in the vicinity of the workpiece 9, and supplies it to a processing point like FIG. In this case, the coolant used may be either water-insoluble or water-soluble.

FIG. 2 is a block diagram focusing on a signal (input) system obtained from the superfinishing machine of the control device 19 and a signal (output) system output to the superfinishing machine and external devices (dressing 25, grindstone exchanger 26). .

That is, the control device 19 includes an A / D conversion function 20a, a D / A conversion function 20b, an arithmetic processing function (CPU) 21, and an I / O interface 24.
The CPU 21 is connected to the main component force sensor 6a, the back component force sensor 6b, the swing load sensor 6c, the movement amount sensor 7 and the in-process gauge 8 provided on the superfinishing board via the A / D conversion function 20a. The output of each of the three component forces P, Q, R output from the main component force sensor 6a, the back component force sensor 6b, and the swing load sensor 6c, and the measurement output S from the movement amount sensor 7 and the in-process gauge 8 , Collect T.
On the other hand, the CPU 21 is connected to each inverter circuit 27 of the spindle motor 22 and the swing motor 23 of the superfinishing machine via the D / A conversion function 20b. At the same time, the CPU 21 is connected to the electropneumatic air regulator 28 of the air cylinder 5 through the D / A conversion function 20b. Therefore, the CPU 21 determines the processing state of the grindstone 10 based on the detection outputs of the main component force sensor 6a, the back component force sensor 6b, the swing load sensor 6c, the movement amount sensor 7 and the in-process gauge 8. Then, the spindle motor 22, the swing motor 23, and the air cylinder 5 are controlled to operate the rotational speed of the workpiece 9, the swing speed of the grindstone 10, and the pressure applied to the grindstone 10, and the machining conditions for the superfinishing processing are real-time. It comes to control with.
The CPU 21 is connected to the air cylinder 5 via the I / O interface 24. In this way, when an abnormality of the grindstone 10 is detected from the detection outputs of the main component force sensor 6a, the back component force sensor 6b, the swing load sensor 6c, the movement amount sensor 7 and the in-process gauge 8, the swing is stopped. Can be commanded to the air cylinder 5.
Further, the CPU 21 can be connected to the

external devices

25 and 26 via the I / O interface 24 to instruct maintenance operation of the grindstone 10.
Here, the external devices are the dressing device 25 for sharpening and the grindstone changing device 26, both of which may be well known. Both

devices

25 and 26 determine that the CPU 21 is necessary based on the detection outputs of the main component force sensor 6a, the back component force sensor 6b, the swing load sensor 6c, the movement amount sensor 7 and the in-process gauge 8. When the command is issued, the sharpening and replacement of the grindstone 10 are automatically performed.

As described above, the processing apparatus of the present application is configured, and next, super finishing used in the processing apparatus will be described.

First, consider cylindrical grinding using a rotating grindstone 30 as shown in FIG. In this case, the workpiece 9 is rotated by the fixed center 1 and the turner 2 as shown in FIG. When the workpiece 9 is ground with the rotary grindstone 30, the normal back force P acting on the workpiece 9 with the

strain gauges

31a and 31b attached to the fixed center 1 and the tangential grinding main portion By measuring the force Q, the load on the grindstone 10 can be digitized and the grinding state can be estimated.

From this concept, next, consider a case where the conditions set in FIG. 4 are given to the cylindrical workpiece 9 supported as shown in FIG.
In other words, the “coarse” condition for lowering the spindle speed and increasing the swing speed and increasing the maximum crossing angle, and conversely the “finishing” condition for increasing the spindle speed and lowering the swing speed and reducing the maximum crossing angle. When the whetstone 10 is continuously given, each signal obtained as the grindstone 10 shifts from the cutting state to the polishing state with respect to the input condition changes. An example of the signal change is shown in FIG.

In FIG. 5, the horizontal axis represents time transition, and the vertical axis represents signal strength (grinding resistance). After the machining starts, the state of the grindstone 10 changes in accordance with the transition from the “rough” machining to the “finishing” machining.
At this time, the detection outputs of the main component force sensor 6a, the back component force sensor 6b, and the swing load sensor 6c are three axes (X axis, Y axis) of the main component force Q, the back component force P, and the swing load R, respectively. , Z-axis) direction component, and as shown in FIG. 5, a signal including the frequency resulting from the number of rotations of the workpiece 9 and the number of oscillations of the grindstone 10 is presented. Each signal varies according to the processing state of the grindstone 10.

FIG. 6 shows signal changes of the moving amount (grinding wheel wear amount) S of the grindstone 10 and the finish dimension reduction amount (stock amount: so-called “removing allowance”) T of the workpiece 9 of the in-process gauge 8. Here, the horizontal axis represents time transition, and the vertical axis represents the amount of displacement.
In this case, in the process of the “coarse” condition, the grindstone 10 is crushed and dropped. Therefore, the moving amount S of the grindstone 10 increases (advances) at a constant speed. At the same time, the finishing dimension reduction amount T also decreases at a constant rate.
On the other hand, in the process of the “finishing” condition, since the processing state of the grindstone 10 is polished, the moving amount S of the grindstone 10 is constant (the forward movement of the rod 13 of the air cylinder 5 is stopped), and the finish. The change in the dimension reduction amount T is also stagnant.

FIG. 7 shows a component force Q (so-called “main component force”) in the tangential direction of rotation of the workpiece 9 of the force applied to the grindstone 10 when machining is performed under the conditions set in FIG. An example of measuring the component force P in the contact direction (so-called “back component force”) and its ratio P / Q is shown. Here, the horizontal axis of FIG. 7 indicates the time transition, and the vertical axis indicates the magnitude of each component force and the ratio thereof.
From FIG. 7, when the machining start point is A, the grindstone 10 actively and spontaneously blades in “rough” machining (cutting state). Thereafter, when shifting to the “finishing” process, the grindstone 10 shifts from a semi-cut state to a clogged state (polished state).
Here, attention is focused on the component force Q in the pressing direction and the component force P in the tangential direction during this period. Then, the component force P in the tangential direction is determined by the pressing force of the grindstone 10. From this, it can be seen that the condition of FIG. 4 shows a substantially constant value.
At this time, the component force Q in the pressing direction shows a change according to the grinding resistance between the workpiece 9 and the grindstone 10.
Specifically, in the “rough” processing, the grindstone 10 spontaneously cuts and the grinding resistance increases. Therefore, the component force Q in the pressing direction takes a large value. Thereafter, during the “finishing” process, the self-generated blade stops and the grindstone 10 is polished. Therefore, the grinding resistance is reduced, and the component force Q in the pressing direction takes a small value. As a result, the ratio P / Q (representing the load balance) shows a change according to the processing state of the grindstone 10 as shown in FIGS.
That is, the ratio P / Q shows a gradual increase as shown in FIG. 7 (b) as the process shifts from “rough” to “finish”.
In the case of the grindstone 10 having the same specifications, this ratio P / Q shows almost the same tendency regardless of which numerical value is set in the processing conditions of FIG. Therefore, the ratio P / Q is effective as an index for monitoring the processing efficiency and finishing accuracy in super finishing.

8 shows the grinding wheel wear amount, which is the moving amount (advance amount) S of the grindstone 10 on the same time axis as FIG. 7, the finishing dimension reduction amount T of the workpiece 9, and the moving amount S of the grinding stone 10 and the finishing dimension reduction amount T. The super-finishing ratio U is taken as the cumulative ratio.
That is, the superfinishing ratio U is obtained by accumulating the “dimension reduction amount (removed volume)” detected by the in-process gauge 8 from the start of machining, and the movement amount S obtained by the movement amount sensor 7 (whetstone wear amount + workpiece). Only the grinding wheel wear amount is calculated from the dimensional reduction amount of the article 9 and is taken as a ratio with the cumulative amount from the start of machining. At this time, the grinding wheel wear amount can be calculated by subtracting the “dimension reduction amount (removed volume)” detected by the in-process gauge 8 from the movement amount S.
In the present apparatus, in order to obtain the grinding efficiency with the in-process gauge 8, the superfinishing ratio U is expressed by the ratio of the cumulative value of the amount of wear of the grinding wheel 10 from the start of machining and the finishing dimension reduction amount T. is there.

FIG. 9 shows a component force P in the pressing direction and a component force Q in the tangential direction and a ratio P / Q when the material of the workpiece 9 is adhered to the grindstone 10 (adhesion state). Shows changes.
That is, the component force P in the pressing direction, the component force Q in the tangential direction, and the ratio P / Q follow a relatively gradual change in FIG. Then, the component force Q of the said tangential direction shows the tendency to fall instantaneously. As a result, the ratio P / Q increases rapidly as shown in FIG. Therefore, if a limit value (threshold value) is set for the ratio P / Q, the occurrence of adhesion can be detected.

As described above, by providing the main component force sensor 6a, the back component force sensor 6b, and the swing load sensor 6c on the grindstone base 4 that supports the grindstone 10, it is possible to discriminate from "rough" processing to "finishing" processing. Thus, it can be used for super-finishing using the grindstone table 4.
Further, by providing the movement amount sensor 7 and the in-process gauge 8, it is possible to determine the finish. And it becomes possible to judge the processing state of the grindstone 10 comprehensively using those detected values, and the processing conditions (the number of rotations of the workpiece 9, the number of oscillations of the grindstone 10, and the pressing force of the grindstone 10). It is possible to always keep the super-finish ratio U optimally by operating it intentionally.
Furthermore, by using these detected values, it becomes possible to detect grinding abnormalities typified by adhesion. When a grinding abnormality is detected, an external device is operated by an I / O circuit as will be described later. It is also possible to maintain the optimum machining state.
In addition, in this way, the superfinishing ratio can be manipulated arbitrarily, and problems such as clogging and adhesion can be prevented in advance. Although it is inferior, good processing accuracy can be obtained even if a water-soluble coolant that is superior in terms of cooling performance and cost is used.

Next, a control method based on the above principle will be described.
For example, in the superfinishing apparatus, two conditions of “rough” and “finishing” are set as shown in FIG. 4 for the cylindrical workpiece 9 supported as shown in FIG. In this case, the machining apparatus includes the main shaft motor 22 and the swing motor 23 based on the outputs of the main component force sensor 6a, the back component force sensor 6b, the swing load sensor 6c, the movement amount sensor 7, and the in-process gauge 8. Then, the air cylinder 5 is controlled to change the machining conditions.
That is, from FIG. 5, the detection output of the main component force sensor 6a and the back component force sensor 6b is the transition point from the processing start point A where the grindstone 10 and the workpiece 9 contact each other to “rough” processing → “finishing” processing. Fluctuates greatly. Therefore, switching from “rough” machining to “finishing” machining is determined from this variation, and switching control to “finishing” machining is performed.
At this time, the oscillating load sensor 6c receives the oscillating inertia and the machining resistance of the grindstone 10, and thus exhibits a sine wave vibration corresponding to the oscillating number. Therefore, in the “rough” process in which the grindstone 10 is crushed and dropped, the grindstone 10 is in a cutting state and the amplitude of the sine wave is increased. On the other hand, in the “finishing” process, the amplitude of the sine wave is reduced because the grindstone 10 is in a polished state.
Therefore, if the determination is made by adding the detection output of the swing load sensor 6c to the detection output of the main component force sensor 6a and the back component force sensor 6b, the determination accuracy is improved. Therefore, even in the superabrasive grindstone, the determination of the transition from “rough” to “finishing” processing is ensured. For example, automatic switching control from “rough” processing to “finishing” processing can be easily controlled.

On the other hand, “coarse” machining and “finishing” machining can also be discriminated by the detection output of the movement amount sensor 7 and the in-process gauge 8.
That is, as shown in FIG. 6, the movement amount S of the grindstone 10 detected by the movement amount sensor 7 advances at a constant speed because crushing or dropping occurs in “rough” processing. In the “finishing” process, the polishing state is stopped.
Further, the processing characteristics of the finishing dimension reduction amount T of the workpiece 9 measured by the in-process gauge 8 change according to the moving amount (grinding wheel wear) S of the grindstone 10 as shown in FIG.
Therefore, if the output characteristics of the movement amount sensor 7 and the in-process gauge 8 are combined with the detection outputs of the main component force sensor 6a and the back component force sensor 6b, the accuracy of switching control from “rough” to “finish” processing can be improved. .

Here, in general, in the superfinishing process, a processing cycle in which three steps of cutting, semi-cutting, and polishing are regularly repeated is considered good.
Therefore, this machining cycle switching control can be realized by monitoring the dimension reduction amount T of the workpiece 9 based on the detection output of the in-process gauge 8.

Further, as shown in FIG. 7, during the “rough” machining period starting from the machining start point A, the grinding wheel 10 is in a cutting state, and the grinding stone 10 at this time actively blades spontaneously. Then, the process proceeds to “finishing” processing (polished state). Then, the grindstone 10 gradually shifts from a semi-cut state to a clogged state. During this time, the two-way component forces Q and P detected by the main component force sensor 6a and the back component force sensor 6b are not as large as the component force (swing load) R in the swing direction detected by the swing load sensor 6c. A sinusoidal signal including a frequency of the same phase caused by the rotational speed of the workpiece 9 or the vibration frequency of the grindstone 10 is exhibited.
Incidentally, the fluctuation of the component force Q in the tangential direction and the component force P in the pressing direction due to the state change of the grindstone 10 is very small with respect to the amplitude included in the rotation speed or frequency component.
Since the constant minute amplitude appearing in the waveform of the component force Q in the tangential direction and the component force P in the pressing direction has the same phase as the machining characteristics, the ratio P / Q cancels each other and has a relatively low amplitude. It becomes a direct current waveform. For this reason, the ratio P / Q can clearly show the change according to the processing state of the grindstone 10 as shown in FIGS. 7 (a), (b), and (c).
Therefore, the machining process can be determined from the output change pattern. In addition, if the determination is made with the output change pattern as described above, the superfinishing can be performed by determining the processing state of the grindstone 10 regardless of the difference in surface roughness of the workpiece 9 before processing.

By the way, in super finishing, since the processing efficiency fluctuates every moment during one processing cycle, the super finishing ratio U does not become a constant value. Further, since the dimension reduction amount T of the superfinished workpiece 9 is very small, it is not easy to obtain the superfinishing ratio U.
Furthermore, since the amount of change of the grindstone 10 converges to zero from the “finishing” process to the completion of the process, “grinding ratio = workpiece removal amount / whetstone wear amount” used in the grinding process using the rotating grindstone 30 is set. There is a possibility that the numerical value may diverge even if it is calculated with respect to the time axis.
Therefore, as described above, as the superfinishing ratio U, the dimension reduction amount T based on the detection output of the in-process gauge 8 and the movement amount S of the grindstone 10 based on the detection output of the movement amount sensor 7 from the start of machining. Accumulated, a ratio T / S (= dimension reduction amount T / movement amount S) between the accumulated dimension reduction amount T and the movement amount S is calculated, and the grindstone 10 is calculated from the tendency of the calculated ratio to change with respect to the time axis. Estimate the machining state.

That is, FIG. 8 shows the superfinishing calculated from the transition of the movement amount S and dimension reduction amount T of the grindstone 10 when machining under the conditions set in FIG. 4 and the accumulated value of the movement amount S and dimension reduction amount T. The ratio U is drawn.
As shown in FIG. 8, in the “rough” machining starting from point A immediately after the machining starts, the self-generated blade and the workpiece removal proceed at the same time. From this result, if the processing efficiency at the time of grinding in the cutting state is high, the initial gradient of the superfinishing ratio U at the initial stage of processing increases.
As described above, since the machining condition with a large gradient is a condition for increasing the machining efficiency in super-finishing, the rotational speed of the spindle motor 22 and the swing motor 23 of the grinding wheel base 4 are controlled so that the value of U becomes large.

Therefore, by associating the ratio P / Q and the superfinishing ratio U in the control device 19, it is possible to set a machining condition that can obtain the highest machining efficiency according to the shape of the workpiece 9 and the specifications of the grindstone 10.
If such a method is employed, it is possible to reduce processing time adjustment time and processing failure during adjustment, which conventionally requires considerable man-hours.

Further, at this time, the ratio P / Q and the superfinishing ratio U can be used for determining the finished state of the workpiece 9. In this case, when the grindstone 10 is polished and the ratio P / Q rises again, and the machining is completed when the set value is exceeded, stable machining quality can be obtained. Further, by finishing the processing when the detection output of the in-process gauge 8 reaches the finished size, the workpiece 9 can be finished to a predetermined size.

On the other hand, when the workpiece 9 and the grindstone 10 are incompatible, when the processing conditions of the workpiece 9 and the grindstone 10 are incompatible, or when the coolant 11 is incompatible, the metal is attached to the grindstone 10 (attached). Occurs.
In this case, since the grindstone 10 and the workpiece 9 partially make metal contact, the ratio P / Q increases and the size reduction amount T decreases.
Therefore, if the processing state of the grindstone 10 is monitored by combining the change in the ratio P / Q and the dimensional change of the dimensional reduction amount T detected by the in-process gauge 8, the occurrence of adhesion can be detected.
At this time, if adhesion is detected, the air cylinder 5 is retracted via the I / O interface 24 in order to stop the processing. Next, the dressing device 25 connected as an external device via the I / O interface 24 is operated to perform dressing (sharpening) of the grindstone 10. Next, the air cylinder 5 is advanced to return to the finishing process and the work is continued.
Then, when it is detected that the adhesion is not improved when the operation is continued, the grindstone exchanging device 24 connected as an external device via the I / O interface 24 is operated to replace the grindstone 10 with a new one. To do. After the replacement, the air cylinder 5 is advanced to return to the polishing process and the operation is continued. Thus, if it responds to abnormality of the grindstone 10, an automatic driving | operation can be continued stably.

In addition, in the present application, since the super-finishing ratio U can be changed by freely operating the processing efficiency, a water-soluble coolant can be used during processing as shown in FIG.
That is, the ratio P / Q is sequentially calculated from the tangential component force Q detected by the main component sensor 6a and the pressing component component Q detected by the back component sensor 6b, and the calculated ratio P / Q is When the value changes below a preset lower limit value, the number of oscillations of the grindstone table 4 is increased or the number of rotations of the workpiece 9 is decreased to increase the machining efficiency. On the other hand, when the ratio P / Q is larger than the preset upper limit value, the number of oscillations of the grindstone table 4 is decreased or the number of rotations of the workpiece 9 is increased to lower the machining efficiency.
Thus, clogging due to adhesion or adhesion can be prevented in advance by changing the processing efficiency and arbitrarily setting the superfinishing ratio U and setting the limit value to the ratio P / Q. For this reason, even if the coolant 11 to be used is a water-soluble coolant that is clogged due to inferior cleanability and lubricity and is likely to cause adhesion, it is possible to set processing conditions that hardly cause these problems.
Therefore, water-soluble coolant that is excellent in cooling performance and cost can be used in the superfinishing process, and as a result, the productivity can be improved by improving the quality of the superfinishing process and reducing the production cost. Further, even when a conventional water-insoluble coolant is employed, the machining efficiency can be optimally maintained by adopting the above-described machining control, which can contribute to a reduction in production cost.

Even when super-finishing is performed using a water-soluble coolant with inferior machining performance, the output P (back component force) of the back component force sensor 6b and the output Q (main component force) of the main component force sensor 6a are sequentially calculated. It is also possible to maintain optimum machining efficiency by feeding back to the machining conditions.

In this way, the processing state of the grindstone 10 is monitored to determine the processing state for each of “rough” processing and “finishing” processing, and can be maintained optimally, so switching from rough processing to finishing processing is automatically performed. Can be done.
Moreover, since the processing state of the grindstone 10 can be monitored to detect adhesion of the grindstone 10, dressing and replacement of the grindstone 10 can be automatically performed.
Furthermore, since the processing state of the grindstone 10 can be monitored and the processing efficiency can be kept constant, a good processing state can be maintained even with a water-soluble coolant that is inferior in lubricity and cleanability to a water-insoluble (oil-based) coolant.

Hereinafter, a specific example of the control method is shown as Example 1.

The processing apparatus according to the first embodiment includes a main shaft motor 22, a swing motor based on outputs from the main component force sensor 6 a, back component force sensor 6 b, swing load sensor 6 c, movement amount sensor 7, and in-process gauge 8. Control is performed to change the machining conditions by controlling the dynamic motor 23 and the air cylinder 5.

For example, the control device 19 reads the component force Q detected by the main component force sensor 6a and the component force P detected by the back component force sensor 6b during the superfinishing process, and the back of the detected output P of the main component force sensor 6a. The ratio P / Q of the component force P detected by the component force sensor is sequentially calculated.
Then, for example, as shown in FIG. 7, the magnitude of the ratio P / Q is compared with a preset upper limit value Th1 or lower limit value Th2, and control is performed to prevent the superfinishing ratio from being lowered during processing.
Specifically, the controller 19 calculates the ratio P / Q with respect to the rotational speed of the workpiece 9 when the preset ratio P / Q is larger than a preset upper limit value Th1 for determining whether the self-generated blade is insufficient. The ratio of the number of oscillations of the grindstone 10 is increased, that is, the grain trajectory generated on the workpiece surface and the traveling direction of the workpiece surface (tangential direction of rotation of the workpiece). The machining conditions are changed by controlling the spindle motor 22 and the swing motor 23 so that the maximum crossing angle is increased.
In this way, by increasing the ratio of the rocking speed of the grindstone 10 to the rotational speed of the workpiece 9, the self-generated blade of the grindstone 10 is promoted, and a reduction in machining accuracy due to a lack of the self-generated blade of the grindstone 10 is prevented. .
On the other hand, when the calculated ratio P / Q is smaller than a preset lower limit Th2 for determining the excessive self-generated blade of the grindstone 10, the control device 19 swings the grindstone 10 with respect to the rotational speed of the workpiece 9. The machining conditions are changed by controlling the spindle motor 22 and the swinging motor 23 so that the ratio of the dynamic numbers becomes small, that is, the maximum crossing angle becomes small.
In this way, by reducing the ratio of the rocking speed of the grindstone 10 to the rotational speed of the workpiece 9, the superfinishing ratio is prevented from being lowered due to excessive self-generated blades of the grindstone 10.

Furthermore, when the ratio P / Q does not become small even if control is performed to change the machining conditions when the previous ratio P / Q becomes larger than the upper limit value Th1, the control unit 19 does not reduce the ratio P / Q. The air cylinder 5 is controlled so as to increase the pressing force against the control to change the machining conditions.
This is because, during superfinishing, the grinding resistance is reduced due to a lack of self-generated blades of the grindstone 10 and the main component force Q is reduced, so that the ratio P / Q is set to an upper limit value Th1 set in advance. It is because it became larger. Therefore, by changing the processing conditions so as to increase the pressing force of the grindstone 10 against the workpiece 9, the self-generated blade of the grindstone 10 is promoted, and the deterioration of the processing accuracy due to the lack of the self-generated blade of the grindstone 10 is prevented.

Similarly, if the ratio P / Q does not increase even if control is performed to change the machining condition when the previous ratio P / Q becomes smaller than the lower limit Th2, the control device 19 does not increase the ratio P / Q. The processing conditions are changed by controlling the air cylinder 5 so as to reduce the pressing force of the grindstone 10 against 9.
This is because the main component force Q increases and the ratio P / Q is a preset lower limit because the cutting force increases due to excessive self-generated blades of the grindstone 10 during superfinishing. This is because the value is smaller than the value Th2. Therefore, by changing the machining conditions so that the pressing force of the grindstone 10 against the workpiece 9 is reduced, the superfinishing ratio is prevented from being lowered due to excessive self-generated blades of the grindstone 10.

Further, the control device 19 detects that the ratio P / Q to be sequentially calculated during the superfinishing process is larger than a preset abnormality detection threshold Th3 as shown in FIG. 9, for example. Then, it determines with the extreme clogging having generate | occur | produced in the grindstone 10. FIG.
This is because the main component force Q is too low when the machining resistance is too low due to the extreme clogging of the grindstone 10 during superfinishing. For this reason, it is determined that the grindstone 10 is extremely clogged. Thereby, it becomes possible to discover the abnormality of the grindstone 10 at an early stage, and it is possible to prevent generation of defective products due to clogging of the grindstone 10.
At this time, if the control device 19 determines clogging, the control device 19 activates the dressing device 25 for dressing via the I / O interface 24. Then, the clogged grindstone 10 is sharpened using the activated dressing device 25. When the setting is finished, the control device 19 performs super finishing. When the productivity reduction due to dressing is disliked, the grindstone exchanging device 26 is activated via the I / O interface 24 and the grindstone 10 is exchanged. Thus, the maintenance operation is performed.

At the same time, the control device 19 calculates the superfinishing ratio U from the detected values of the movement amount sensor 7 and the in-process gauge 8 during superfinishing, so that the calculated superfinishing ratio U becomes an optimum value. The machining conditions are controlled by controlling the motor 22, the swing motor 23, and the air cylinder 5.
That is, the superfinishing ratio U is obtained by accumulating the “dimension reduction amount (removed volume)” detected by the in-process gauge 8 from the start of machining, and the movement amount S obtained by the movement amount detection sensor 7 (whetstone wear amount + Only the grinding wheel wear amount is calculated from the dimension reduction amount of the workpiece 9 and is taken as a ratio with the cumulative amount from the start of machining. Therefore, the control device 19 samples and accumulates the detection output of the in-process cage 8 and the output of the movement amount detection sensor 7 at regular intervals, and calculates the superfinishing ratio U by taking the ratio of the accumulated values. In this way, the superfinishing ratio U is detected in real time.
At this time, the grinding wheel wear amount is calculated by subtracting the “dimension reduction amount (removed volume)” detected by the in-process gauge 8 from the movement amount S, for example.
Then, the machining conditions of the spindle motor 22, the swing motor 23, and the air cylinder 5 are controlled so as to approach the superfinishing ratio U set so that the cost of the finished dimension reduction amount and the wear amount of the grindstone 10 are harmonized. . By doing so, the processing cost can be reduced.

Further, the control device 19 determines the machining state by detecting the output of the rocking load sensor 6c. Based on the determination, the number of rotations of the workpiece 9, the number of rocking of the grindstone, and the pressing of the grindstone 10 are determined. A stable machining state is obtained by changing machining conditions such as force.

Therefore, as shown in FIG. 5, the control device 19 determines the shortage of the self-generated blade of the grindstone 10 and sets the amplitude lower limit value Th4 set in advance and the amplitude of the component force R detected by the swing load sensor 6c. Compare sequentially. When the amplitude of the component force R becomes smaller than a preset lower limit Th4 of the amplitude, the spindle motor 22 and the swing motor 23 are controlled. Then, the machining state is changed so that the ratio of the rocking speed of the grindstone 10 to the rotational speed of the workpiece 9 is increased, that is, the maximum crossing angle is increased.
By controlling in this way, when the grinding resistance becomes small due to the lack of the self-generated blade of the grindstone 10, the self-generated blade of the grindstone 10 is promoted, and the processing accuracy is reduced due to the lack of the self-generated blade of the grindstone 10. To prevent.

In addition, the use of the swing load sensor 6c that can detect the state of the self-generated blade as described above prevents the superfinishing ratio U from being lowered.
In this case, as shown in FIG. 5, the control device 19 determines the excess of the self-generated blade of the grindstone 10, and the magnitude of the amplitude of the component force R detected by the preset upper limit value Th5 and the swing load sensor 6c. Are compared sequentially. When the amplitude of the component force R becomes larger than the preset upper limit value Th5 of the amplitude, the spindle motor 22 and the swing motor 23 are controlled to swing the grindstone 10 with respect to the rotational speed of the workpiece 9. The machining conditions are changed so that the ratio of the numbers becomes smaller, that is, the maximum crossing angle becomes smaller.
If it does in this way, when resistance becomes large because of the excessive self-generated blade of the grindstone 10, the self-generated blade of the grindstone 10 is suppressed, and the fall of the super finishing ratio U by the excessive self-generated blade of the grindstone 10 is prevented. it can.

Further, at this time, the control device 19 sequentially compares the amplitude of the component force R detected by the swing load sensor 6c with a preset lower limit Th6 of the amplitude in order to determine whether the self-generated blade is insufficient. When the amplitude becomes smaller than the lower limit value Th6, the processing conditions are changed so as to increase the pressing force of the grindstone 10 against the workpiece 9 by controlling the air cylinder 5.
If it does in this way, when processing resistance becomes small, since the self-generated blade of the grindstone 10 is accelerated | stimulated, the fall of the processing precision by the lack of the self-generated blade of the grindstone 10 can be prevented.

Conversely, the control device 19 sequentially compares the amplitude of the component force R detected by the swing load sensor 6c with an amplitude upper limit value Th7 set in advance in order to determine the excessive self-generated blade. Then, when the amplitude becomes larger than the upper limit value Th7, the processing conditions are changed so as to control the air cylinder 5 to reduce the pressing force of the grindstone 10 against the workpiece 9.
In this way, when the processing resistance increases due to excessive self-generated blades of the grindstone 10, the pressing force of the grindstone 10 against the workpiece 9 is reduced, and the self-generated blades of the grindstone 10 are suppressed, and the grindstone 10 It is possible to suppress a decrease in the superfinishing ratio U due to excessive self-generated blades.

In this second embodiment, a case where the superfinishing of the present application is applied to a tapered roller bearing will be described.
FIGS. 10A and 10B schematically show the processing. Here, FIG. 10A shows the super-finishing of the tapered inner ring 40 and FIG. 10B shows the super-finishing of the outer ring 41. By setting in this way, it is possible to improve the superfinishing quality and productivity of the tapered roller bearing.
10 (a) and 10 (b), reference numeral 14 denotes a shoe, 15 denotes a packing plate, 3 denotes a rocking device, 4 denotes a grindstone base, 5 denotes an air cylinder, 6a denotes a main component force sensor, and 6b spine. A force sensor, 6c swing load sensor, 7 is a potentiometer, and 8 is an in-process gauge.
In the present application, since the force applied to the grindstone 10 is detected instead of detecting the force applied to the member that supports the workpiece (in this case, the inner ring 40), the machining state of the grindstone 10 is determined regardless of the method of supporting the workpiece. Can be determined. Therefore, the range of application of workpieces is wide.
Therefore, the present invention can be applied to super finishing of a workpiece supported by a chuck gripping type, a center supporting type, or the like. It can also be applied to super finishing of tapered rollers.
Therefore, it is possible to provide a tapered roller bearing that uses these inner rings, outer rings, and tapered rollers to improve the quality and productivity of superfinishing.

Example 3 describes a machine part to which the present invention is applied.
11 (a) to 11 (d) show typical bearings to which the present invention is applied and application locations in parts constituting the bearings.
FIG. 11A shows a ball bearing 50 in which a plurality of balls 53 are incorporated between an inner ring 51 and an outer ring 52. 11 (b) and 11 (c) show a processing target portion 54 for performing the superfinishing of the present application in the ball bearing of FIG. 11 (a). FIG. 11 (b) is provided on the outer periphery of the inner ring 51. The machining can be performed as shown in FIG. 10A on the raceway surface having an arcuate cross section. FIG. 10C shows a rolling surface provided on the inner periphery of the outer ring, and the processing may be as shown in FIG.
FIG. 11 (d) shows a machining target portion 54 for the “roller” 55 of the self-aligning roller bearing, and shows the outer periphery of the convex roller 55 having a convex outer diameter as the machining target portion 54. Is.

DESCRIPTION OF SYMBOLS 1 Fixed center 2 Turner 3 Oscillating device 4 Grinding wheel base 5 Air cylinder 6a Main component force sensor 6b Back component force sensor 6c Oscillating load sensor 7 Movement amount sensor 8 In-process gauge 9 Workpiece 10 Grinding stone 11 Water-soluble coolant 12 Discharge Nozzle 13 Rod 14 Shoe 15 Packing plate 40 Inner ring 41 Outer ring 50 Ball bearing 51 Inner ring 52 Outer ring 53 Ball 54 Location to be processed 55 Roller P Component force Q Component force R Component force S Travel amount T Finish dimension reduction amount U Super finish ratio

Claims

Rotate the workpiece, press the grinding stone against the workpiece while swinging the grinding stone in a direction perpendicular to the tangential direction of the workpiece rotation, and superfinish the workpiece to support the grinding stone A main component force sensor for detecting a component force Q in a tangential direction of rotation of the workpiece applied to the grindstone in a state of being pressed against the workpiece, and a grindstone in a state of being pressed against the workpiece And a back component force sensor that detects a component force P in the pressing direction of the grindstone of the force applied to the grinding wheel, and superfinishing that determines the machining state of the workpiece based on the component forces P and Q detected by each sensor Method.
The grindstone table includes an air cylinder that advances the rod and presses the grindstone supported at the tip against the workpiece, and the main component force between the tip of the rod of the air cylinder to which the grindstone is attached and the grindstone The superfinishing method according to claim 1, wherein a sensor and the back component force sensor are arranged.
An in-process gauge for detecting a reduction in the size of the workpiece due to machining with a grindstone, and a movement amount sensor for detecting a movement amount in the pressing direction of the grindstone due to a reduction in the size of the workpiece and wear of the grindstone. 3. The machining state of the workpiece is determined based on a dimension reduction amount of the workpiece detected by the in-process gauge and a movement amount of the grindstone detected by the movement sensor. Super finishing method.
The workpiece is rotated, and the grinding wheel is pressed against the workpiece while swinging the grinding wheel in a direction perpendicular to the tangential direction of the rotation of the workpiece, thereby superfinishing the workpiece and supporting the grinding wheel. A main component force sensor for detecting a component force Q in a tangential direction of rotation of the workpiece applied to the grindstone in a state of being pressed against the workpiece, and a grindstone in a state of being pressed against the workpiece And a back component force sensor for detecting a component force P in the pressing direction of the grindstone of the force applied to the grinding wheel, and superfinishing for controlling the superfinishing process based on the component forces P and Q detected by each sensor. Processing method.
The grindstone table includes an air cylinder that advances the rod and presses the grindstone supported at the tip against the workpiece, and the main component force between the tip of the rod of the air cylinder to which the grindstone is attached and the grindstone The superfinishing method according to claim 4, wherein a sensor and the back component force sensor are arranged.
The control of the superfinishing process performed based on the respective component forces P and Q sequentially calculates the ratio P / Q of the component force P detected by the back component force sensor to the component force Q detected by the main component force sensor. Then, when the magnitude of the ratio P / Q becomes larger than a preset upper limit value, the control is performed to change the machining condition so that the ratio of the rocking speed of the grindstone to the rotational speed of the workpiece becomes large. The superfinishing method according to claim 4 or 5.
The control of the superfinishing process performed based on the respective component forces P and Q sequentially calculates the ratio P / Q of the component force P detected by the back component force sensor to the component force Q detected by the main component force sensor. Then, when the magnitude of the ratio P / Q becomes smaller than a preset lower limit value, control is performed to change the machining conditions so that the ratio of the rocking speed of the grindstone to the rotational speed of the workpiece becomes small. The superfinishing method according to any one of claims 4 to 6.
The control of the superfinishing process performed based on the respective component forces P and Q sequentially calculates the ratio P / Q of the component force P detected by the back component force sensor to the component force Q detected by the main component force sensor. In addition, when the magnitude of the ratio P / Q becomes larger than a preset upper limit value, control is performed to change the machining conditions so as to increase the pressing force of the grindstone against the workpiece. The superfinishing method according to any one of the above.
The control of the superfinishing process performed based on the respective component forces P and Q sequentially calculates the ratio P / Q of the component force P detected by the back component force sensor to the component force Q detected by the main component force sensor. In addition, when the magnitude of the ratio P / Q becomes smaller than a preset lower limit value, control is performed to change the machining conditions so as to reduce the pressing force of the grindstone against the workpiece. The superfinishing method according to any one of the above.
The control of the superfinishing process performed based on the respective component forces P and Q sequentially calculates the ratio P / Q of the component force P detected by the back component force sensor to the component force Q detected by the main component force sensor. The control according to any one of claims 4 to 9, wherein when the magnitude of the ratio P / Q becomes larger than a preset abnormality detection threshold, it is determined that an extreme clogging has occurred in the grindstone. The superfinishing method according to any one of the above.
An in-process gauge for detecting a reduction in the size of the workpiece due to machining with a grindstone, and a movement amount sensor for detecting a movement amount in the pressing direction of the grindstone due to a reduction in the size of the workpiece and wear of the grindstone. The ratio of the wear amount of the grinding wheel to the dimensional reduction amount of the workpiece based on the dimension reduction amount of the workpiece detected by the in-process gauge and the movement amount of the grinding wheel detected by the movement amount sensor. The superfinishing method according to any one of claims 4 to 10, wherein a superfinishing ratio is calculated.
A wobble load sensor for detecting a component force R in a wobbling direction of the grindstone of the force applied to the whetstone pressed against the workpiece is further provided on the grindstone table that supports the whetstone. The superfinishing method according to any one of claims 4 to 11, wherein the superfinishing process is controlled based on the detected amplitude of the component force R.
In the super finishing process control based on the amplitude of the component force R, the amplitude of the component force R detected by the swing load sensor is smaller than a preset lower limit width. 13. The superfinishing processing method according to claim 12, wherein the processing condition is controlled so that a ratio of a rocking speed of the grindstone to a rotational speed of the workpiece is increased.
In the superfinishing control performed based on the amplitude of the component force R, the amplitude of the component force R detected by the swing load sensor is larger than a preset upper limit width. The superfinishing processing method according to claim 12 or 13, wherein control is performed to change a processing condition so that a ratio of a rocking speed of the grindstone to a rotational speed of the workpiece is small.
In the super finishing process control based on the amplitude of the component force R, the amplitude of the component force R detected by the swing load sensor is smaller than a preset lower limit width. The superfinishing method according to any one of claims 12 to 14, wherein the machining condition is controlled to increase the pressing force of the grindstone against the workpiece.
In the superfinishing control performed based on the amplitude of the component force R, the amplitude of the component force R detected by the swing load sensor is larger than a preset upper limit width. The superfinishing method according to any one of claims 12 to 15, wherein control is performed to change a machining condition so as to reduce a pressing force of a grindstone against the workpiece.
The superfinishing method according to any one of claims 1 to 16, wherein a water-soluble coolant is used as a coolant supplied between the workpiece and the grindstone.
The superfinishing method according to any one of claims 1 to 17, wherein the workpiece is any one of an inner ring, an outer ring, and a rolling element of a bearing.
A super finishing machine that rotates a workpiece and presses the grindstone against the workpiece while swinging the grindstone in a direction perpendicular to the tangential direction of the rotation of the workpiece;
A main component force sensor that is attached to a grindstone table that supports the grindstone and that detects a component force Q in a tangential direction of rotation of the workpiece that is applied to the grindstone while being pressed against the workpiece;
A back component force sensor that is attached to a grindstone table that supports the grindstone and that detects a component force P in the pushing direction of the grindstone of a force applied to the grindstone in a state of being pressed against the workpiece;
A superfinishing apparatus having a control device for controlling the superfinishing process based on the component forces P and Q detected by the sensors.
The grindstone table includes an air cylinder that advances the rod and presses the grindstone supported at the tip against the workpiece, and a main component force sensor between the tip of the rod of the air cylinder to which the grindstone is attached and the grindstone The superfinishing processing apparatus according to claim 19, further comprising a control device that includes a back component force sensor and controls the superfinishing processing based on the component forces P and Q detected by the sensors.
The control device sequentially calculates a ratio P / Q of the component force P detected by the back component force sensor to the component force Q detected by the main component force sensor, and the magnitude of the ratio P / Q is preset. 21. The superfinishing apparatus according to claim 19 or 20, wherein control is performed to change a machining condition so that a ratio of a rocking speed of the grindstone to a rotation speed of the workpiece increases when the upper limit is exceeded. .
The control device sequentially calculates a ratio P / Q of the component force P detected by the back component force sensor to the component force Q detected by the main component force sensor, and the magnitude of the ratio P / Q is preset. The superposition according to any one of claims 19 to 21, wherein control is performed to change a machining condition so that a ratio of a rocking speed of the grindstone to a rotation speed of the workpiece becomes small when the lower limit is exceeded. Finishing device.
The control device sequentially calculates a ratio P / Q of the component force P detected by the back component force sensor to the component force Q detected by the main component force sensor, and the magnitude of the ratio P / Q is preset. The superfinishing apparatus according to any one of claims 19 to 22, wherein control is performed to change a machining condition so as to increase a pressing force of a grindstone against the workpiece when the upper limit is exceeded.
The control device sequentially calculates a ratio P / Q of the component force P detected by the back component force sensor to the component force Q detected by the main component force sensor, and the magnitude of the ratio P / Q is preset. The superfinishing apparatus according to any one of claims 19 to 23, wherein control is performed to change a machining condition so as to reduce a pressing force of a grindstone against the workpiece when the lower limit is exceeded.
An in-process gauge for detecting a dimensional reduction amount of the workpiece by machining with a grindstone;
A movement amount sensor for detecting a movement amount in the pressing direction of the grindstone due to a reduction in size of the workpiece and wear of the grindstone;
The control device is configured to wear the grinding wheel with respect to the dimensional reduction amount of the workpiece based on the dimensional reduction amount of the workpiece detected by the in-process gauge and the movement amount of the grinding wheel detected by the movement amount sensor. The superfinishing apparatus according to any one of claims 19 to 24, wherein a superfinishing ratio that is a ratio of amounts is calculated.
A wobble load sensor that detects a component force R in a wobbling direction of the grindstone of a force applied to the grindstone in a state of being pressed against the workpiece on the grindstone support that supports the whetstone;
26. The superfinishing apparatus according to any one of claims 19 to 25, wherein the control apparatus controls the superfinishing process based on an amplitude of a component force R detected by the swing load sensor.
The superfinishing apparatus according to any one of claims 19 to 26, further comprising a discharge nozzle that supplies water-soluble coolant between the workpiece and the grindstone.