JP6488894B2 - Cylindrical workpiece grinding machine - Google Patents

Description

  The present invention relates to a grinding apparatus for grinding an outer peripheral surface of a cylindrical workpiece.

  Conventionally, a through-feed centerless grinding apparatus is known as an apparatus for grinding an outer peripheral surface of a cylindrical workpiece such as an outer ring of a rolling bearing. As shown in FIG. 9, this grinding apparatus is configured so that a plurality of cylindrical workpieces W pass between a grinding wheel 90 having a columnar shape and an adjustment wheel 91 along a blade 92. This is an apparatus for grinding by bringing a grindstone 90 into contact with the outer peripheral surface.

However, in the through-feed centerless grinding apparatus, there is no clear position as a machining reference on the apparatus, and in order to obtain desired accuracy (dimension, roundness, roughness, etc.), the grindstone 90 and the adjustment wheel 91 are Although it is necessary to finely adjust the arrangement of each mechanism part such as the interval and the work core height, the work largely depends on the trial and error of the operator. For this reason, when the size (model number) of the cylindrical workpiece W is changed, it is necessary to change the interval between the grindstone 90 and the adjustment wheel 91, but it takes time to change (step change). In particular, when multi-mix production or multi-product small lot production is performed, it is necessary to frequently change the setup, and in this case, the operating rate of the apparatus is significantly reduced and productivity is deteriorated.
When performing such through-feed centerless grinding, it is necessary to reduce the grinding allowance (removal allowance) once, and in order to obtain a desired accuracy, the grindstone 90 and the adjustment wheel having a plurality of sets of different intervals. It is necessary to line up the grinding devices including 91 and pass the cylindrical workpiece W sequentially through these grinding devices. For this reason, it is necessary to adjust all of these plural sets of grinding apparatuses when changing the setup.

  As another apparatus for grinding the outer peripheral surface of a cylindrical workpiece, an in-feed grinding apparatus is known (for example, see Patent Document 1). For example, as shown in FIG. 10, the apparatus includes two shoes 99 that support the cylindrical workpiece W from below, a chuck 98a that holds the cylindrical workpiece W, and a rotation mechanism 98 that includes a motor (not shown) that rotates the chuck 98a. And a grindstone 97.

Japanese Utility Model Publication No. 6-11957

  The in-feed grinding apparatus is suitable for grinding an outer peripheral surface of a cylindrical workpiece that is relatively thick like an inner ring of a rolling bearing. In other words, when the grinding device is used to grind the outer peripheral surface of the outer ring, which is a relatively thin rolling bearing, the cylindrical workpiece W is crushed and deformed by the contact force of the grindstone 97 as shown in FIG. Therefore, desired accuracy (for example, roundness) cannot be obtained. In particular, when the feed speed of the grindstone 97 is increased in order to increase the production efficiency, the grinding resistance increases and the deformation of the cylindrical workpiece W increases, making it difficult to ensure accuracy.

Therefore, in order to suppress the deformation of the cylindrical workpiece W due to the contact with the grindstone 97, the feed speed of the grindstone 97 may be set low, but in this case, the grinding time (cycle time) becomes long and the productivity is lowered. .
Thus, in the case of an in-feed grinding apparatus, improvement in accuracy (machining accuracy) and improvement in productivity are in a trade-off relationship, and it has been considered impossible to satisfy these simultaneously.

  In the technique disclosed in Patent Document 1, a cylindrical work is pushed from above by a roller. As a result, even if the cylindrical workpiece is about to deform, it can be corrected by the roller. However, it is possible to perform roughing using the apparatus disclosed in Patent Document 1, but it is difficult to perform finishing that requires high accuracy. This is because the grinding stone feed speed is reduced when finishing processing. In this case, although the grinding resistance is small and the cylindrical work is hardly deformed, the upper roller presses the cylindrical work so that the cylindrical work is moved. This is because the deformation is unnecessarily small, but this deformation adversely affects the accuracy required for finishing.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a cylindrical workpiece grinding apparatus capable of improving machining accuracy while shortening grinding time.

  A grinding apparatus for a cylindrical workpiece for achieving the object includes a rotating mechanism for rotating the cylindrical workpiece around a center line of the cylindrical workpiece, and a grindstone for performing grinding by bringing the cylindrical workpiece into contact with the outer peripheral surface of the rotating cylindrical workpiece. A correction mechanism that has a contact portion that can contact the outer peripheral surface of the cylindrical workpiece at a position different from that of the grindstone, and suppresses deformation of the cylindrical workpiece due to contact with the grindstone; In the first time zone, the contact portion is brought into contact with the outer peripheral surface of the cylindrical workpiece to perform grinding with the grindstone, and in the second time zone after the first time zone and including the end of grinding, the contact portion is A grinding control unit that performs grinding by reducing the feed speed of the grindstone while being separated from the cylindrical workpiece.

According to this grinding apparatus, in the first time zone, the deformation of the cylindrical workpiece due to the contact of the grindstone is suppressed by bringing the contact portion into contact with the outer peripheral surface of the cylindrical workpiece. Can be faster. Thereby, grinding time is shortened. In the subsequent second time zone, grinding is performed by reducing the feed speed of the grindstone while the contact portion is separated from the cylindrical workpiece, so that the deformation of the cylindrical workpiece due to the contact with the grindstone is suppressed, and the contact portion is cylindrical. Since the work is not forcibly pushed, the accuracy of the cylindrical work can be increased. As described above, it is possible to improve accuracy while shortening the grinding time.
In addition, although the feed rate of the grindstone is lowered in the second time zone, this means that the feed rate of the grindstone is lowered in the first time zone, and when the feed rate has a low value. In addition, the case where the feed rate is set to zero is included.

The first time zone includes a time zone during which rough machining is performed on the outer circumferential surface of the workpiece, and the second time zone is a time zone during which finishing machining is performed on the outer circumferential surface of the workpiece, and a spark. It is preferable to include at least the spark-out time zone among the out-time zones.
In this case, rough machining can be performed in a short time, production efficiency can be improved, and grinding can be performed with high machining accuracy in the second time zone.

The correction mechanism further includes an actuator capable of pressing the contact portion against the cylindrical workpiece and changing a pressing force, and the grinding control unit controls the operation of the actuator. It can be set as the structure which has a pressure control part which controls the said pressing force.
In this case, it is possible to suppress the deformation of the cylindrical workpiece by setting the pressing force of the contact portion against the cylindrical workpiece to a predetermined value.

In the case of controlling the pressing force, the pressure control unit acquires load information regarding a reaction force generated when the grindstone comes into contact with the cylindrical workpiece, and based on the acquired load information, It is preferable to adjust the output of the actuator by feedback control of the actuator.
There is a correlation between the feed speed of the grindstone and the reaction force generated by bringing the grindstone into contact with the cylindrical workpiece. Therefore, by acquiring load information related to the reaction force and adjusting the output of the actuator based on the load information, the pressing force of the contact portion is changed according to the contact state (contact force) of the grindstone with respect to the cylindrical workpiece. Can do. As a result, the contact portion comes into contact with the cylindrical workpiece by an appropriate pressing force, and the deformation of the cylindrical workpiece can be suppressed.
In this case, when the load information when the reaction force increases is acquired, the pressure control unit increases the output of the actuator and acquires the load information when the reaction force decreases. Then, it is preferable to reduce the output of the actuator.
When the reaction force increases, the grindstone is in strong contact with the cylindrical workpiece, and in this case, the cylindrical workpiece is in a state of being easily deformed. Can be suppressed.

Alternatively, in the case of controlling the pressing force as described above, the pressure control unit has a storage unit that stores output information of the actuator corresponding to the pressing force, and based on the output information, It can be set as the structure which performs control which operates an actuator.
In this case, the contact portion can be brought into contact with the cylindrical workpiece with a predetermined pressing force, and deformation of the cylindrical workpiece can be suppressed.

  In addition to the control of the pressing force as described above, the correction mechanism is an actuator that can press the contact portion against the cylindrical workpiece and change the relative position between the cylindrical workpiece and the contact portion. And the grinding control unit can be configured to include a position control unit that controls the operation stroke of the actuator to adjust the relative position between the cylindrical workpiece and the contact unit. Control may be performed. That is, the relative position between the cylindrical workpiece and the contact portion can be maintained at a predetermined value, and the deformation of the cylindrical workpiece can be suppressed by the contact portion.

  In the cylindrical workpiece grinding apparatus, the contact portion may have any shape that does not hinder the rotation of the cylindrical workpiece, and is a roller that is rotatable around a center line that is parallel to the outer peripheral surface of the cylindrical workpiece. In this case, the contact portion (roller) can be rotated by contacting the rotating cylindrical workpiece, and a good contact state can be obtained.

  According to the present invention, even when grinding is performed on the outer peripheral surface of a thin cylindrical workpiece, it is possible to improve accuracy while shortening the grinding time.

It is explanatory drawing which looked at one Embodiment of the grinding-work apparatus of a cylindrical workpiece from the side. It is explanatory drawing which looked at a part of grinding apparatus from the top. It is a graph for demonstrating each process included in a grinding process. It is a flowchart of the pressure control (the 1). It is explanatory drawing explaining the mode of operation | movement of the grinding apparatus shown in FIG. It is explanatory drawing explaining the mode of operation | movement of the grinding apparatus shown in FIG. It is a flowchart of pressure control (the 2). It is a flowchart of position control. It is explanatory drawing which looked at the through-feed centerless grinding apparatus from the top. It is explanatory drawing which looked at the conventional in-feed grinding apparatus from the side. It is explanatory drawing which looked at the conventional in-feed grinding apparatus from the side.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Configuration of grinding device for cylindrical workpiece]
FIG. 1 is an explanatory view of a cylindrical workpiece grinding apparatus according to an embodiment of the present invention as viewed from the side. FIG. 2 is an explanatory view of a part of the grinding apparatus as viewed from above. The grinding apparatus 1 is an apparatus for grinding an outer peripheral surface of a hollow cylindrical workpiece such as an outer ring of a rolling bearing. In the present embodiment, a cylindrical workpiece is described as an outer ring W of a rolling bearing. The outer ring W is thinner than the inner ring provided on the radially inner side, and is more easily deformed than the inner ring by an external force applied from the radial direction. In addition, the outer ring W is thinner than the inner ring in terms of the ratio to the radius, and has low rigidity and is easily deformed. Therefore, even when grinding is performed on the outer peripheral surface f of the outer ring W, the grinding apparatus 1 of the present embodiment reduces the grinding time while reducing the accuracy (dimension, roundness, roughness). Etc.) can be increased for grinding. Hereinafter, the configuration will be described.

  The grinding apparatus 1 includes a rotation mechanism 10 that rotates the outer ring W, a grindstone 7, a correction mechanism 20, and a grinding control unit 30. The grinding apparatus 1 shown in FIG. 1 further includes two shoes 8 and 9 as a supporting member that supports the outer ring W from below, and a measuring device 6 that measures the diameter of the outer ring W.

  The rotation mechanism 10 includes a chuck 11 that holds the outer ring W, and a drive motor 12 (see FIG. 2) that rotates the chuck 11. The chuck 11 of the present embodiment is a magnet chuck, and holds the outer ring W such that the center line C1 of the outer ring W coincides with the rotation center line of the chuck 11. When the drive motor 12 rotates the chuck 11, the outer ring W can be rotated around the center line C1.

  The shoes 8 and 9 are provided at a position below the center line C1 of the outer ring W held by the chuck 11. One shoe 8 is provided on the side opposite to the grindstone 7 and is provided at a position to support the outer ring W so that it does not escape when the grindstone 7 contacts and presses the outer ring W. The other shoe 9 is provided on the grindstone 7 side, and is provided at a position to support the outer ring W together with the one shoe 8 from below so that it does not fall.

The grindstone 7 has a disc shape (annular shape) and is attached to a holder that is rotated by a grindstone motor, although not shown. The grindstone 7 rotates around the center line C2 of the grindstone 7 by the rotation of the grindstone motor. Further, the holder (not shown) is configured to be moved back and forth by the grindstone actuator 5 (see FIG. 2), whereby the grindstone 7 can move toward and away from the outer ring W to be ground. The grindstone actuator 5 moves the grindstone 7 toward or away from the outer ring W and moves the grindstone 7 in the approaching direction based on a command signal from the grinding control unit 30, that is, feed of the grindstone 7 Or change the speed.
And the grindstone 7 grinds by contacting the outer peripheral surface f of the rotating outer ring W. At this time, the grinding controller 30 controls the operation of the grindstone actuator 5, and the outer peripheral surface f of the outer ring W can be ground while the grindstone 7 is operated at a predetermined feed rate.

In FIG. 1, the correction mechanism 20 has a contact portion that can contact the outer peripheral surface f of the outer ring W. In the present embodiment, the contact portion is a roller 21. Further, the correction mechanism 20 has a correction actuator 22 that operates the roller 21. The correction actuator 22 may be an air cylinder, and may have a mechanism (for example, a ball screw mechanism) that converts the rotation of the servo motor into a linear movement, a hydraulic mechanism (hydraulic cylinder), and the like. When pressure control (Part 1) and (Part 2) described below are employed, the actuator 22 is an air cylinder. When position control described below is employed, the actuator 22 converts the rotation of the servo motor into linear movement. It has a mechanism. In any case, the actuator 22 can linearly move the rod 23 along its longitudinal direction. A roller 21 is attached to the tip of the rod 23. In particular, the roller 21 is attached to the rod 23 so as to be rotatable around a center line C3 parallel to the outer peripheral surface f of the outer ring W.
In the form shown in FIG. 1, the grindstone 7 comes into contact with the outer ring W from the horizontal direction, and the roller 21 comes into contact with the outer ring W from the vertical direction. Contact with f is possible at a position different from the contact position with the grindstone 7.

  When the straightening actuator 22 advances the rod 23, the roller 21 can be pressed against the outer ring W, and by moving the rod 23 forward and backward, the relative position between the outer ring W and the roller 21 can be changed. . The correction mechanism 20 further includes a displacement sensor 24 that manages (measures) the operating distance of the actuator 22, that is, the movement stroke of the roller 21 (rod 23). The measurement value of the displacement sensor 24 is transmitted to the grinding control unit 30.

  Further, when the straightening actuator 22 is an air cylinder, the straightening mechanism 20 further includes a pressure control function such as an electropneumatic regulator in order to adjust the pressure of the air that operates the actuator 22. Therefore, the actuator 22 can press the roller 21 against the outer ring W and can change the pressing force of the roller 21 against the outer ring W. The change (adjustment) of the pressing force is performed by the grinding control unit 30, although a specific example will be described later.

  According to the correction mechanism 20 as described above, the deformation (distortion) of the outer ring W due to the contact with the grindstone 7 can be suppressed regardless of the type of the actuator 22 for correction. That is, when the grindstone 7 comes into contact with the outer ring W with a predetermined feed speed (> 0) for grinding, the outer ring W having low rigidity tends to be deformed. The deformation of the outer ring W can be suppressed by bringing the rollers 21 into contact with different portions.

  The grinding control unit 30 includes a programmable logic controller (PLC), and is configured to perform various types of control when the arithmetic unit (CPU) executes various programs stored in the storage unit 31 such as an internal memory. . The grinding control unit 30 has at least one of the pressure control unit 32 and the position control unit 33 as a functional unit that performs various controls. These functional units will be described later.

  The measuring device 6 is for measuring the diameter (diameter) of the outer ring W to be ground, and is composed of a contact sensor in this embodiment. The diameter of the outer peripheral surface f of the outer ring W that decreases in diameter as the grinding progresses is measured every moment by the measuring device 6, and the measured value is transmitted to the grinding control unit 30.

[About grinding method]
The grinding process performed by the grinding apparatus 1 having the above configuration will be described.
As shown in FIG. 1, the outer ring W is placed on the shoes 8 and 9. At this time, the grindstone 7 and the roller 21 are in a retracted position away from the outer ring W. Then, the chuck 11 holds the outer ring W on the shoes 8 and 9, and the outer ring W is rotated around the center line C <b> 1 by the rotation mechanism 10. Further, the grindstone 7 is rotated and the correction mechanism 20 is brought into an operable state. Then, the outer peripheral surface f of the outer ring W is ground by the grindstone 7 while pressing the roller 21 against the outer ring W by the correction mechanism 20.

  Here, each process included in the grinding process will be described. The grinding process includes a first roughing process, a second roughing process, a finishing process, and a spark-out process. Management (operation control) of each process performed in this order is performed by the grinding control unit 30. Done. The first roughing process and the second roughing process are processes for roughing the outer peripheral surface f of the outer ring W, and these are included in the roughing process. FIG. 3 is a graph for explaining these steps. In this graph, the horizontal axis represents the elapsed time from the start of grinding S1 to the end of grinding S5, and the vertical axis represents the processing amount (grinding amount). As shown in FIG. 3, the processing amount increases with time, and the outer ring W obtained by grinding for a predetermined processing amount has a finished dimension K.

  The first roughing step is a black skin removing step, and in this step, the grinding stone 7 is brought into contact with the outer peripheral surface f of the outer ring W to remove the black skin layer. In the first roughing process, the feed speed V1 of the grindstone 7 is increased. Specifically, it is faster than the feed speed V3 in the finishing process (V1> V3).

  In the second roughing step, a predetermined machining allowance is further removed from the outer peripheral surface f of the outer ring W from which the black skin layer has been removed. In the second roughing process, the feeding speed V2 of the grindstone 7 is set to be the fastest. Specifically, it is faster than the feed speed V1 in the first roughing process (V2> V1).

  In the finishing process, a finishing process is performed on the outer peripheral surface f of the outer ring W after the roughing process to obtain a finished surface. In this finishing process, the grindstone feed speed V3 is decreased. Specifically, it is slower than the feed speeds V1 and V2 in the first roughing process and the second roughing process (V3 <V1 <V2).

  In the spark-out step, the grindstone 7 is rotated without giving a cut to the outer ring W that has been finished. That is, in this spark-out process, the feed speed V4 of the grindstone 7 is zero (V4 = 0). This spark-out process is performed to eliminate uncut portions on the outer peripheral surface f of the outer ring W and to improve the accuracy of the finished surface.

From the above, when the feeding speed of the grindstone 7 in each step included in the grinding process of the present embodiment is summarized, V4 (= 0) <V3 <V1 <V2.
Thus, the outer peripheral surface f of the outer ring W is ground by the grindstone 7 while changing the feed speed of the grindstone 7. During this time, the grinding control unit 30 and the correction mechanism 20 function to suppress deformation of the outer ring W caused by the contact of the grindstone 7. The control performed by the grinding control unit 30 and the correction mechanism 20 is one of pressure control and position control. Hereinafter, pressure control (part 1), pressure control (part 2), and position control will be described.

[Pressure control (part 1)]
In the first roughing process and the second roughing process, pressure control (part 1) for controlling the pressing force of the roller 21 against the outer ring W is performed. In FIG. 3, “correction execution range” indicates a range in which this pressure control (part 1) is performed. FIG. 4 is a flowchart of pressure control (part 1). The pressure control (part 1) is executed by the pressure control unit 32 (indicated as PLC in FIG. 4).

  When the first roughing process is started by a command signal from the pressure control unit 32 (step St11 in FIG. 4), the operation of the correction mechanism 20 is also started (step St21). That is, according to the command signal, the grindstone 7 is brought into contact with the outer peripheral surface f of the outer ring W and the roller 21 is pressed against the outer peripheral surface f of the outer ring W with a predetermined pressing force as shown in FIG. In the first roughing step, the grindstone 7 is fed at a constant feed speed V1, and grinding is performed in contact with the outer ring W.

When the grindstone 7 comes into contact with the outer ring W, a grinding resistance acts on the grindstone 7, and this grinding resistance affects the current value of the drive motor 12 (see FIG. 2) included in the rotation mechanism 10. Therefore, the pressure control unit 32 monitors the current value i of the driving motor 12 as load output information (load information) of the grindstone 7 that contacts the outer ring W (step St31 in FIG. 4).
Based on the current value i, the pressure control unit 32 performs feedback control so that the roller 21 presses the outer ring W at the set condition pressure. That is, the current value i varies when grinding is performed with the feed speed V1 of the grindstone 7 constant. Therefore, when the acquired current value i increases, the pressure control unit 32 increases the output of the actuator 22 formed of an air cylinder and increases the pressing force of the roller 21 against the outer ring W. On the other hand, when the acquired current value i decreases, the pressure control unit 32 reduces the output of the actuator 22 formed of an air cylinder and weakens the pressing force of the roller 21 against the outer ring W.

  This means that an increase in the current value i means that the grinding resistance of the grindstone 7 is increased, and the outer ring W is easily deformed when the grinding resistance is increased. This deformation is suppressed by increasing the pressing force. The lower current value i means that the grinding resistance of the grindstone 7 becomes smaller. When the grinding resistance becomes smaller, the outer ring W becomes difficult to deform. Deformation of the outer ring W is prevented by reducing the pressing force.

The pressure controller 32 performs such pressure control, and when the first roughing process is completed (step St12 in FIG. 4), the second roughing process is started (step St13). With the start of the second roughing process, the feed speed of the grindstone 7 is increased (changes from the feed speed V1 to the feed speed V2). And also in this 2nd roughing process, the pressure control part 32 monitors the electric current value i of the drive motor 12 as the information of the load output of the grindstone 7 which contacts the outer ring W (step St32 of FIG. 4).
Based on the current value i, the pressure control unit 32 performs feedback control so that the roller 21 presses the outer ring W at the set condition pressure (step St22 in FIG. 4). When grinding is performed with the feed speed V2 of the grindstone 7 constant, the current value i varies. Therefore, when the acquired current value i increases, the pressure control unit 32 increases the output of the actuator 22 and increases the pressing force of the roller 21 against the outer ring W. On the other hand, when the acquired current value i decreases, the pressure control unit 32 decreases the output of the actuator 22 and weakens the pressing force of the roller 21 against the outer ring W.

  This also means that the current value i increases in the second roughing process, which means that the grinding resistance of the grindstone 7 increases, and the outer ring W easily deforms when the grinding resistance increases. In such a case, this deformation is suppressed by increasing the pressing force of the roller 21. The lower current value i means that the grinding resistance of the grindstone 7 becomes smaller. When the grinding resistance becomes smaller, the outer ring W becomes difficult to deform. Deformation of the outer ring W is prevented by reducing the pressing force.

  The pressure control unit 32 performs such pressure control, and when the second roughing process is finished (step St14 in FIG. 4), that is, when a predetermined machining allowance is removed, a finishing process is started (step St15). Along with the start of the finishing process, the feed speed of the grindstone 7 is decreased (changed from the feed speed V2 to the feed speed V3). Further, along with the start of the finishing process, the actuator 22 is operated by the command signal from the pressure control unit 32 to move the roller 21 backward (step St23), and the roller 21 and the outer ring W are moved as shown in FIG. Contactless. In addition, the grindstone 7 and the outer ring | wheel W are in a rotation state continuously.

  When the finishing process ends (step St16), that is, when a predetermined accuracy is obtained, the spark-out process is started (step St17). In the spark-out process, the feeding of the grindstone 7 is stopped (feed speed V4 = 0), and the grindstone 7 and the outer ring W are rotated for a predetermined time. When the predetermined time has elapsed, the grindstone 7 is separated from the outer ring W, the rotation of the outer ring W and the grindstone 7 is stopped, and the grinding is finished.

  As described above, the pressure control unit 32 of the grinding control unit 30 performs the roughing process (the first roughing process and the second roughing process) after the grinding start S1 of the outer ring W as shown in FIG. In the 1-hour period T1, the roller 21 is brought into contact with the outer peripheral surface f of the outer ring W to perform grinding with the grindstone 7 (see FIG. 5). Then, in the second time zone T2 after the first time zone T1 and performing the spark-out process including the grinding end S5 and the finishing process before that, the roller 21 is separated from the outer ring W (FIG. 6). Reference), the grinding speed is controlled by lowering the feed speed of the grindstone 7 below the feed speeds V1 and V2 in the roughing process.

  And the actuator 22 which the correction mechanism 20 of this embodiment has is the structure which can press the roller 21 with respect to the outer ring | wheel W and can change a pressing force as mentioned above. Therefore, in this pressure control (part 1), the pressure control unit 32 controls the pressing force by controlling the operation of the actuator 22. That is, there is a correlation between the feed speed (V1, V2) of the grindstone 7 and the reaction force generated by bringing the grindstone 7 into contact with the outer ring W. Therefore, the pressure control unit 32 acquires load information related to the reaction force, and adjusts the output of the actuator 22 based on the load information, so that the grinding wheel 7 is in contact with the outer ring W (contact force). The pressing force of the roller 21 against the outer ring W can be changed.

  This pressure control (part 1) will be specifically described. The pressure control unit 32 acquires the current value i of the drive motor 12 (see FIG. 2) that rotates the grindstone 7 as load information regarding the reaction force generated when the grindstone 7 comes into contact with the outer ring W. Then, the pressure control unit 32 performs feedback control of the actuator 22 based on the acquired load information (current value i) and performs control for adjusting the output of the actuator 22.

For example, when the load information (current value i) when the reaction force increases is acquired, the pressure control unit 32 increases the output of the actuator 22 and loads information (current value) when the reaction force decreases. When i) is acquired, the output of the actuator 22 is reduced. When the reaction force increases, the grindstone 7 is in strong contact with the outer ring W. In this case, the outer ring W is in a state of being easily deformed, and therefore, the pressing force by the roller 21 is increased to suppress deformation of the outer ring W. can do. On the other hand, when the reaction force is small, the grindstone 7 is in relatively weak contact with the outer ring W. In this case, since the deformation of the outer ring W is small, the pressing force by the roller 21 is reduced, The deformation of the outer ring W is suppressed.
As described above, according to the pressure control (part 1), the roller 21 comes into contact with the outer ring W by an appropriate pressing force, and the deformation of the outer ring W with which the grindstone 7 comes into contact can be suppressed.

In the first roughing process and the second roughing process, feedback control is performed so that the roller 21 presses the outer ring W by the set condition pressure. There is a correlation between the set condition pressure and the output of the actuator 22, and the output of the actuator 22 for obtaining a predetermined set condition pressure is predetermined by the pressure control unit 32.
The set condition pressure can be expressed as load output of the grindstone 7 × setting coefficient. The setting coefficient can be freely changed by inputting and can take any value. Further, different setting factors can be employed in the first roughing process and the second roughing process.

[Pressure control (part 2)]
The pressure control performed by the pressure control unit 32 with respect to the pressing force of the roller 21 against the outer ring W may be another procedure. In the case of this pressure control (part 2) as well, the pressing force of the roller 21 against the outer ring W is controlled in the first roughing process and the second roughing process. That is, the “correction implementation range” shown in FIG. 3 is a range in which this pressure control (part 2) is performed. FIG. 7 is a flowchart of pressure control (part 2). The pressure control (part 2) is executed by the pressure control unit 32 (referred to as PLC in FIG. 7).

  When the first roughing process is started by a command signal from the pressure control unit 32 (step St41 in FIG. 7), the operation of the correction mechanism 20 is also started (step St51). That is, according to the command signal, the grindstone 7 is brought into contact with the outer peripheral surface f of the outer ring W and the roller 21 is pressed against the outer peripheral surface f of the outer ring W with a predetermined first pressing force as shown in FIG. In the first roughing step, the grindstone 7 is fed at a constant feed speed V1, and grinding is performed in contact with the outer ring W.

  The first pressing force is controlled by the pressure control unit 32 so as to be constant. For this reason, an output value of the actuator 22 that only applies the first pressing force from the roller 21 to the outer ring W is determined, and a command signal for operating the actuator 22 with this output value is stored in the internal memory ( It is stored in the storage unit 31). The actuator 22 is an air cylinder. Therefore, the command signal is transmitted from the pressure control unit 32 to the actuator 22 during the first roughing process. As a result, the actuator 22 operates with a predetermined output value, and the roller 21 can be pressed against the outer ring W by the first pressing force.

  The pressure controller 32 performs such pressure control, and when the first roughing process is finished (step St42 in FIG. 7), the second roughing process is started (step St43). With the start of the second roughing process, the feed speed of the grindstone 7 is increased (changes from the feed speed V1 to the feed speed V2). Also in this second roughing process, the roller 21 is pressed against the outer ring W by a predetermined second pressing force (step St52).

  The second pressing force is controlled by the pressure control unit 32 so as to be constant. For this purpose, an output value of the actuator 22 that gives the second pressing force from the roller 21 to the outer ring W is determined, and a command signal for operating the actuator 22 with this output value is stored in the internal memory ( It is stored in the storage unit 31). Therefore, the command signal is transmitted from the pressure control unit 32 to the actuator 22 during the second roughing process. As a result, the actuator 22 operates with a predetermined output value, and the roller 21 can be pressed against the outer ring W by the second pressing force.

  The pressure control unit 32 performs such pressure control, and when the second roughing process is completed (step St44 in FIG. 7), that is, when a predetermined machining allowance is removed, the finishing process is started (step St45). Along with the start of the finishing process, the feed speed of the grindstone 7 is decreased (changed from the feed speed V2 to the feed speed V1). Further, at the start of this finishing process, the actuator 22 is operated by the command signal from the pressure control unit 32 to move the roller 21 backward (step St53), and the roller 21 and the outer ring W are moved as shown in FIG. Contactless. In addition, the grindstone 7 and the outer ring | wheel W are in a rotation state continuously.

  When the finishing process is completed (step St46), that is, when a predetermined accuracy is obtained, the spark-out process is started (step St47). In the spark-out process, the feeding of the grindstone 7 is stopped (feed speed V4 = 0), and the grindstone 7 and the outer ring W are rotated for a predetermined time. When the predetermined time has elapsed, the grindstone 7 is separated from the outer ring W, the rotation of the outer ring W and the grindstone 7 is stopped, and the grinding is finished.

  In the first roughing process and the second roughing process, the roller 21 is controlled to press the outer ring W by the first and second pressing forces, but the first and second pressing forces can be changed respectively. And can take any value. Further, different pressing forces can be employed in the first roughing process and the second roughing process.

  As described above, the pressure control unit 32 of the grinding control unit 30 performs the roughing process (the first roughing process and the second roughing process) after the grinding start S1 of the outer ring W as shown in FIG. In the 1-hour period T1, the roller 21 is brought into contact with the outer peripheral surface f of the outer ring W to perform grinding with the grindstone 7 (see FIG. 5). Then, in the second time zone T2 after the first time zone T1 and performing the spark-out process including the grinding end S5 and the finishing process before that, the roller 21 is separated from the outer ring W (FIG. 6). Reference), the grinding speed is controlled by lowering the feed speed of the grindstone 7 below the feed speeds V1 and V2 in the roughing process.

  And the actuator 22 which the correction mechanism 20 of this embodiment has is the structure which can press the roller 21 with respect to the outer ring | wheel W and can change a pressing force as mentioned above. Therefore, in this pressure control (part 2), the pressure control unit 32 controls the pressing force by controlling the operation of the actuator 22.

Therefore, the storage unit 31 included in the pressure control unit 32 outputs, as output information of the actuator 22 corresponding to the first and second pressing forces, outputs for obtaining the first and second pressing forces. The command signal for operating the actuator 22 is stored. And the pressure control part 32 performs control which operates the actuator 22 based on the output information (command signal) memorize | stored in the memory | storage part 31 in each of a 1st roughing process and a 2nd roughing process. Thereby, in each of the first roughing process and the second roughing process, the roller 21 can be brought into contact with the outer ring W with a predetermined pressing force.
Note that the deformation of the outer ring W to be ground by the grindstone 7 is suppressed by bringing the roller 21 into contact with the outer ring W with a constant pressing force in this way. The outer ring W is ground at a constant rate in each step. Based on that.

[Position control]
In addition to the pressure control (part 1) (part 2) for controlling the pressing force of the roller 21 against the outer ring W as described above, position control is performed for performing control to adjust the relative position between the outer ring W and the roller 21. The correction mechanism 20 may function. In this position control, the position of the roller 21 relative to the outer ring W is controlled in the first roughing process and the second roughing process. That is, the “correction implementation range” shown in FIG. 3 is a range in which this position control is performed. FIG. 8 is a flowchart of position control. The position control is executed by the position control unit 33 (referred to as PLC in FIG. 8).

  When the first roughing process is started by a command signal from the position controller 33 (step St61 in FIG. 8), the operation of the correction mechanism 20 is also started (step St71). That is, according to the command signal, the grindstone 7 is brought into contact with the outer peripheral surface f of the outer ring W and the roller 21 is pressed against the outer peripheral surface f of the outer ring W with a predetermined pressing force as shown in FIG. In the first roughing step, the grindstone 7 is fed at a constant feed speed V1, and grinding is performed in contact with the outer ring W.

The diameter of the outer peripheral surface f of the outer ring W gradually decreases as the grinding progresses. The position control unit 33 can obtain the distance between the outer peripheral surface f and the roller 21 whose diameter decreases with the passage of time by calculation. Then, the position control unit 33 performs control to operate the actuator 22 so that the distance becomes zero. The diameter of the outer ring W may be a value obtained in advance based on the feed speed V1 of the grindstone 7 and stored in the internal memory (storage unit 31), or measured by the measuring device 6 during grinding. It may be a value.
As described above, in this position control, the position control unit 33 controls the operation of the actuator 22 so that the roller 21 is positioned with a distance from the outer peripheral surface f of the outer ring W being zero. For this reason, the actuator 22 has a mechanism (for example, a ball screw mechanism) that converts the rotation of the servo motor into a linear movement, thereby enabling fine position control of the roller 21.

  The position control unit 33 performs such position control, and when the first roughing process is completed (step St62 in FIG. 8), the second roughing process is started (step St63). With the start of the second roughing process, the feed speed of the grindstone 7 is increased (changes from the feed speed V1 to the feed speed V2). Also in this second roughing step, the position control unit 33 operates the actuator 22 so that the distance between the outer peripheral surface f of the outer ring W and the roller 21 gradually decreases as the grinding progresses. Control is performed (step St72).

  The position control unit 33 performs such position control, and when the second roughing process is finished (step St64 in FIG. 8), that is, when the predetermined machining allowance is removed, the finishing process is started (step St65). Along with the start of the finishing process, the feed speed of the grindstone 7 is decreased (changed from the feed speed V2 to the feed speed V1). Further, at the start of this finishing process, the actuator 22 is operated by the command signal from the position control unit 33 to move the roller 21 backward (step St73), and the roller 21 and the outer ring W are moved as shown in FIG. Contactless. In addition, the grindstone 7 and the outer ring | wheel W are in a rotation state continuously.

  When the finishing process is completed (step St66), that is, when a predetermined accuracy is obtained, the spark-out process is started (step St67). In the spark-out process, the feeding of the grindstone 7 is stopped (feed speed V4 = 0), and the grindstone 7 and the outer ring W are rotated for a predetermined time. When the predetermined time has elapsed, the grindstone 7 is separated from the outer ring W, the rotation of the outer ring W and the grindstone 7 is stopped, and the grinding is finished.

  As described above, the pressure control unit 32 of the grinding control unit 30 performs the roughing process (the first roughing process and the second roughing process) after the grinding start S1 of the outer ring W as shown in FIG. In the 1-hour period T1, the roller 21 is brought into contact with the outer peripheral surface f of the outer ring W to perform grinding with the grindstone 7 (see FIG. 5). Then, in the second time zone T2 after the first time zone T1 and performing the spark-out process including the grinding end S5 and the finishing process before that, the roller 21 is separated from the outer ring W (FIG. 6). Reference), the grinding speed is controlled by lowering the feed speed of the grindstone 7 below the feed speeds V1 and V2 in the roughing process.

  And the actuator 22 which the correction mechanism 20 of this embodiment has is a structure which can press the roller 21 with respect to the outer ring W, and can change the relative position of the outer ring W and the roller 21 as mentioned above. Therefore, in this position control, the position control unit 33 performs control to adjust the relative position between the outer ring W and the roller 21 by controlling the operation stroke of the actuator 22. That is, the position control of the roller 21 is performed so as to follow the outer peripheral surface f of the outer ring W whose diameter decreases with the lapse of grinding time. Thereby, the relative position between the outer ring W and the roller 21 can be maintained at a predetermined value (zero in this embodiment), and the deformation of the outer ring W with which the grindstone 7 comes into contact can be suppressed by the roller 21.

[About each form]
As described above, according to the grinding apparatus 1 shown in FIG. 1, in the first time zone T <b> 1 (see FIG. 3) in which roughing is performed, the grinding wheel 7 is brought into contact with the outer peripheral surface f of the outer ring W by contacting the roller 21. The deformation of the outer ring W due to the contact of the wheel is suppressed, and the feed speed (V1, V2) of the grindstone 7 can be increased in the first time zone T1. Thereby, grinding time is shortened.
Then, in the second time zone T2 thereafter, the outer ring W caused by the contact of the grindstone 7 is performed by reducing the feed speed (V3, V4) of the grindstone 7 while grinding the roller 21 away from the outer ring W. Further, since the roller 21 is not forced to push the outer ring W, the accuracy (roundness) of the outer ring W can be improved. As described above, even when grinding the thin outer ring W, it is possible to increase the accuracy while reducing the grinding time by in-feed grinding.
And if the outer ring | wheel W is set to the grinding apparatus 1, it can complete from a 1st roughing process to a spark-out process. That is, it is possible to perform a plurality of processes in a single device 1 and to reduce the size of the production line.

  In the present embodiment, the contact portion that is brought into contact with the outer peripheral surface f of the outer ring W is a roller 21 that is rotatable about a center line C3 that is parallel to the outer peripheral surface f. For this reason, the roller 21 can be rotated by contacting with the rotating outer ring W, and a preferable contact state is obtained. For example, it becomes difficult to be damaged by sliding contact.

In the embodiment (see FIG. 3), the first time zone T1 is a time zone during which rough machining is performed on the outer circumferential surface f of the outer ring W, and the second time zone T2 is the outer circumferential surface f of the outer ring W. The case where it is both the time zone which finishes with respect to and the time zone of a spark out was demonstrated. However, the boundary between the first time zone T1 and the second time zone T2 may be other than the form shown in FIG. For example, the first time zone T1 includes a time zone in which finishing is performed in addition to a time zone in which rough machining is performed on the outer peripheral surface f of the outer ring W, and the second time zone T2 is only in a spark-out time zone. It may be.
That is, the first time zone T1 includes a time zone during which rough machining is performed on the outer circumferential surface f of the outer ring W, and the second time zone T2 is a time zone during which finishing machining is performed on the outer circumferential surface f of the outer ring W. And at least the spark-out time zone among the spark-out time zones. Thereby, rough machining can be performed in a short time, production efficiency can be improved, and grinding can be performed with high machining accuracy in the second time zone T2.

The embodiments disclosed above are illustrative in all respects and not restrictive. That is, the grinding apparatus of the present invention is not limited to the illustrated form, and may be of another form within the scope of the present invention.
For example, in the above-described embodiment, the case where the shoes 8 and 9 are used as the supporting members that support the outer ring W from below (shoe grinding) has been described. However, other grinding processes that perform grinding without using such shoes 8 and 9 are described. It may be a device. In the case of cylindrical grinding without using a shoe, for example, the outer ring W can be gripped (core pushed) from both sides in the axial direction, and the outer ring W can be rotated for grinding.
Moreover, although the grinding | polishing object was demonstrated as the outer ring | wheel W of a rolling bearing, the cylindrical workpiece | work made into the object may be another thing, and the inner ring | wheel of a rolling bearing may be sufficient as it. Further, it may be a long cylindrical workpiece that is long in the axial direction. In this case, it is preferable to use a support member in order to prevent deflection due to its own weight.
Furthermore, although the case where the correction mechanism 20 has the single roller (contact part) 21 was demonstrated, you may have the some roller (contact part) 21. FIG. That is, the position pressed with respect to the outer peripheral surface f of the outer ring | wheel W may be multiple places.
Moreover, although the said embodiment demonstrated that the measuring device 6 might be used at the time of a process, it is also possible to process without using the measuring device 6 at the time of a process.
Moreover, although the said embodiment demonstrated the case where the feed speed V2 of the grindstone 7 in a 2nd roughing process is faster than the feed speed V1 in a 1st roughing process (V2> V1), it differs from this. There are also patterns. That is, the feed speed V1 of the grindstone 7 in the first roughing process may be equal to or higher than the feed speed V2 in the second roughing process (V1 ≧ V2).

1: Grinding device 7: Grinding wheel 10: Rotating mechanism 20: Correction mechanism 21: Roller (contact part) 22: Actuator 30: Grinding control part 31: Storage part 32: Pressure control part 33: Position control part W: Outer ring (cylindrical) F) Outer peripheral surface C1: Center line of outer ring C3: Center line of roller T1: First time zone T2: Second time zone V1, V2, V3, V4: Feeding speed

Claims (8)

A rotation mechanism for rotating the cylindrical workpiece around the center line of the cylindrical workpiece;
A grindstone for grinding in contact with the outer peripheral surface of the rotating cylindrical workpiece;
A correction mechanism that has a contact portion that can contact the outer peripheral surface of the cylindrical workpiece at a position different from the grindstone, and suppresses deformation of the cylindrical workpiece due to contact of the grindstone,
In the first time zone after the start of grinding of the cylindrical workpiece, the contact portion is brought into contact with the outer peripheral surface of the cylindrical workpiece to perform grinding with the grindstone, and after the first time zone and including the end of grinding. In the belt, a grinding control unit that performs control by reducing the feed rate of the grindstone in a state where the contact portion is separated from the cylindrical workpiece,
An apparatus for grinding cylindrical workpieces. The first time zone includes a time zone for roughing the outer peripheral surface of the workpiece,
2. The cylindrical workpiece according to claim 1, wherein the second time zone includes at least a spark-out time zone among a time zone in which finishing processing is performed on the outer peripheral surface of the workpiece and a spark-out time zone. Grinding equipment. The correction mechanism further includes an actuator capable of pressing the contact portion against the cylindrical workpiece and changing a pressing force.
3. The cylindrical workpiece grinding apparatus according to claim 1, wherein the grinding control unit includes a pressure control unit that controls an operation of the actuator to control the pressing force. 4.   The pressure control unit acquires load information related to a reaction force generated when the grindstone contacts the cylindrical workpiece, and adjusts the output of the actuator by feedback controlling the actuator based on the acquired load information. The cylindrical workpiece grinding apparatus according to claim 3.   When the load information when the reaction force increases is acquired, the pressure control unit increases the output of the actuator, and when the load information when the reaction force decreases is acquired, the actuator The cylindrical workpiece grinding apparatus according to claim 4, wherein the output of is reduced.   The cylinder according to claim 3, wherein the pressure control unit includes a storage unit that stores output information of the actuator corresponding to the pressing force, and performs control to operate the actuator based on the output information. Work grinding machine. The correction mechanism has an actuator capable of pressing the contact portion against the cylindrical workpiece and changing a relative position between the cylindrical workpiece and the contact portion;
3. The cylinder according to claim 1, wherein the grinding control unit includes a position control unit that controls an operation stroke of the actuator to adjust a relative position between the cylindrical workpiece and the contact unit. Work grinding machine.   The cylindrical work grinding apparatus according to claim 1, wherein the contact portion is a roller that is rotatable around a center line that is parallel to the outer peripheral surface of the cylindrical work.

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