JP6419616B2 - Cleaning method of spindle end face in machining center - Google Patents

Description

The present invention relates to a machining center that performs machining by mounting an arbitrary tool on a main shaft and rotationally driving it, and in particular, a special foil that is sandwiched and consolidated between the end surface of the main shaft and the tool when the tool is replaced. Jo cuttings relates cleaning method of the main shaft end face which is to be effectively cleaned.

  Machining centers are widely used in the industry to select any tool according to the machining purpose from a variety of tools prepared in advance and mount it on the spindle, and drive the spindle to machine machine parts. Yes. In this type of machine tool, in order to obtain the required machining accuracy, it is important to mount the tool on the spindle with high accuracy. However, it is inevitable that a large amount of swarf is generated and scattered at the machining site, and this swarf adheres to the main shaft and tool, and a tapered mounting hole provided on the main shaft when the tool is attached or detached. There was a case in which chips entered into

  In order to avoid such a problem, it is necessary to remove chips adhering to the main shaft and a tool attached to the main shaft. The following Patent Documents 1 to 6 disclose inventions of a cleaning device for cleaning chips adhering to a main shaft or the like of a machine tool or the like. In these inventions, air or coolant liquid is supplied to a path formed in a spindle of a machine tool or a tool, and this is injected from an opening of the path to remove chips and the like.

Japanese Utility Model Publication No. 7-40053 Japanese Patent No. 4175825 Japanese Patent Laid-Open No. 8-281531 JP 2009-233772 A JP 2002-254271 A Japanese Patent No. 4028993

  A tapered attachment hole for attaching a tool is provided at the center of the end surface of a main spindle of a general machine tool, and a chuck for grasping the tool is provided at the back of the attachment hole. Moreover, the tool attached to such a main axis | shaft is provided with the taper-shaped shank part.

  When attaching such a tool to the main shaft, the shank portion of the tool is inserted into an attachment hole of the main shaft, and connected and fixed to the main shaft side with a chuck. At this time, the main shaft and the tool are in close contact with each other at the tapered surfaces, and are also in close contact with the end surface of the main shaft and the end surface on the rear side of the flange of the tool, and the tool is attached to the main shaft with high accuracy in a two-surface constrained state.

  According to the spindle cleaning device in the conventional machine tool as shown in each of the above patent documents, the chips adhering to the spindle and the tool are removed, and the chips entering the spindle mounting hole when the tool is replaced It was possible to remove However, as a result of earnest research on cleaning of the spindle in a machine tool, the inventor of the present application, as will be described below, has a novel existence of special chips formed on the end face of the spindle and a reduction in machining accuracy due to this. It came to discover a subject. In addition, it has also been confirmed that the solution of this problem is difficult with the conventional spindle cleaning apparatus as shown in the above patent documents.

  That is, according to the mounting structure by the two-surface constraint of the tool with respect to the main shaft as described above, the tapered surfaces and the end surfaces are in close contact with each other when the tool is mounted on the main shaft. For this reason, the possibility that chips generated during processing enter the gap between the tapered surface and the end surface is small. However, when the tool is replaced, if the tool is removed from the main shaft, the entire end surface of the main shaft is exposed, so that there is a possibility that chips will adhere to the mounting area where the tool will be in close contact with the end surface of the main shaft. Arise. When the tool is changed, chips adhere to the attachment area on the end face of the spindle.If the next tool is attached to the spindle as it is, the chips in the attachment area on the end face of the spindle will remain between the end faces of the tool flange. It is compressed and crushed to form a foil-like swarf that is stuck to the end face of the main shaft. Even if the thickness of the foil-like chips formed on the end face of the spindle is small after a single tool change, the foil-like chips gradually become thicker as the tool change is repeated several times. It will be stacked.

  When a tool is attached in a state where such foil-like chips are present and a hole is to be drilled with a predetermined hole diameter accuracy, the tip of the tool is shaken and the required hole diameter is changed, The expected accuracy may not be obtained. If the hole diameter becomes large, it must be discarded as a defective product. If the hole diameter becomes small, reworking is necessary and the number of man-hours increases.

The present invention has been made in order to solve the novel problems discovered by the inventors of the present invention described above, and is effective for the compacted special foil-like chips formed on the end face of the spindle of the machining center. and its object is to provide a cleaning method of the main shaft end face which is to be cleaned.

According to the cleaning method of the end face of the spindle in the machining center according to claim 1 ,
After the cleaning tool mounting step of mounting the cleaning tool on the main shaft such that a gap of 3 mm or more is generated between the end surface of the main shaft of the machining center,
A first coolant cleaning step of rotating the spindle at a rotation speed of 100 revolutions per minute or less while supplying coolant into the gap;
A second coolant cleaning step of rotating the main shaft in a direction opposite to the rotation direction of the first coolant cleaning step at a rotation speed of 100 rpm or less while supplying the coolant into the gap;
Have
Thereafter, there is provided a cleaning tool air cleaning step in which the main shaft is rotated while air is blown to the end face from an injection hole opened in the facing surface of the cleaning tool facing the end face across the gap.
In addition, other cleaning processes such as a parallel air flow cleaning process, which will be described later, drying, etc., if necessary, between the cleaning tool mounting process, the first coolant cleaning process, the second coolant cleaning process, and the cleaning tool air cleaning process. This process can be inserted.

According to the cleaning method of the end surface of the main shaft in the machining center of the present invention, the clearance between the end surface of the main shaft and the cleaning tool attached to the end surface of the main shaft is set to 3 mm or more. The coolant can be sufficiently distributed to the end face of the main shaft to which the chip-like chips are adhered. And the sticky foil-like chips can be peeled off by rotating the spindle at a rotation speed of 100 revolutions per minute or less while supplying the coolant. Furthermore, by reversing the spindle under the same conditions, even if there are obstacles related to cleaning such as keys that attach the cleaning tool to the spindle, the end face can be cleaned evenly, and the attached foil-like chips can be further removed. Can be removed reliably. Then, further, if air is sprayed from the spray hole of the cleaning tool facing the end surface of the main shaft across the gap, and air is sprayed to the end surface of the main shaft, peeling is performed by rotating in two directions with different rotational directions while spraying coolant. And the remainder of the foil-shaped chip from which at least a part has been removed is also completely removed, and the end face of the main shaft is in a clean state.

In the machining center according to the embodiment, the main axis and the cleaning tool attached to the main axis are viewed with a line of sight parallel to a horizontal axis (X axis in the coordinate system) perpendicular to the center line of the main axis (Z axis in the coordinate system). FIG. It is the figure which looked at the main axis | shaft which mounted | wore with the cleaning tool in embodiment and was set to the washing | cleaning position with the same eyes | visual_axis as FIG. It is the figure which looked at the main axis | shaft which mounted | wore with the cleaning tool in embodiment and was set to the washing | cleaning position with the eyes | visual_axis parallel to the centerline (Z axis in a coordinate system) of a main axis. FIG. 3 is a partially enlarged sectional view of the cleaning tool and the main shaft in FIG. 2. It is a partial expanded sectional view of the outer peripheral part (A section of FIG. 1) of the main axis | shaft in FIG.

An embodiment of the present invention will be described with reference to FIGS.
1. About the structure of the machining center The machining center of the present embodiment selects an arbitrary tool according to the machining purpose from a plurality of types of tools prepared in advance and mounts it on the spindle, and rotationally drives the spindle to make metal milling and drilling. It is a machine tool that performs various types of machining such as tapping and multi-face machining. The tool includes a cleaning tool 10 (details will be described later) having no cutter used for cleaning the end face of the spindle, in addition to various types of tools provided with a cutter for machining a workpiece. .

  Although not shown, the machining center main body has a sealed processing chamber for processing, and the workpiece is processed while being supplied with coolant in the processing chamber, and coolant, chips, etc. are externally supplied. It is designed not to scatter. As shown in FIG. 1, a main shaft 1 is disposed in parallel to the horizontal direction on a main body (not shown) of the machining center, and one end face 2 is projected as a free end into the machining chamber. The main shaft 1 is rotationally driven at a necessary speed at the time of processing, and can arbitrarily move along each axis of the XYZ coordinate system shown in FIGS. FIG. 1 shows a state in which the main shaft 1 is at the tool attaching / detaching position, and FIGS. 2 and 3 show a state in which the main shaft 1 is in the cleaning position. The positional relationship between the tool attachment / detachment position and the cleaning position is not particularly limited. For example, as illustrated in FIG. 3, a positional relationship in which a predetermined distance is arranged along the X axis may be used.

  As shown in FIG. 1, a tapered attachment hole 3 for attaching a tool is provided in the center of the end surface 2 of the main shaft 1. Further, the inner part of the attachment hole 3 communicates with the cylindrical hole part 4. A chuck 5 for attaching and detaching a tool is provided in the hole portion 4, and the tool attached to the attachment hole 3 can be arbitrarily fixed and released.

  As shown in FIGS. 1 and 5, a plurality of first fluid circuits 6 are formed in the main shaft 1 along the axial direction at positions close to the outer peripheral surface thereof. The plurality of first fluid circuits 6 are provided at equiangular intervals along the circumferential direction of the main shaft 1. In FIG. 1, two first fluid circuits 6 located at positions separated by 180 degrees in the circumferential direction are shown. The first fluid circuit 6 extends from an air source (not shown) on the main body side of the main shaft 1, bends 90 degrees in the axial center direction in the vicinity of the end surface 2 of the main shaft 1, and further branches into two to be tapered. The front and back of the inner surface of the mounting hole 3 are opened. If air is supplied from the air source of the main body to the first fluid circuit 6 with the tool removed, air can be injected into the mounting hole 3, and chips etc. are contained in the mounting hole 3. This can be blown out.

  Further, as shown in FIG. 5 which is an enlarged sectional view of a portion A in FIGS. 1 and 1, a part of the first fluid circuit 6 extends as it is and opens to the end face of the main shaft 1. 8 communicates. An arc-shaped eaves member 19 is attached to the periphery of the end surface 2 of the main shaft 1 so as to cover the first injection port 8. As can be seen from FIG. 5, the eaves member 19 is a member that is fixed to the periphery of the end surface 2 and extends in a cantilever direction toward the center of the main shaft 1. It faces the back side. Therefore, as shown by an arrow in FIG. 5, if air is supplied from the air source of the main body to the first fluid circuit 6, the air from the first fluid circuit 6 is ejected from the first injection port 8 and the eaves member 19, and flows in the center direction along the end surface 2 of the main shaft 1.

  Further, a second fluid circuit 7 is provided in the cylindrical hole portion 4 provided in communication with the tapered mounting hole 3 in the main shaft 1 so that the axis line coincides with the central axis. The second fluid circuit 7 can be selectively connected to an air source or a coolant source (not shown) on the main body side, and can selectively supply air or coolant. For example, when a tool is mounted on the spindle 1, the second fluid circuit 7 is connected to a flow path formed along the axis of the tool, and coolant is sprayed from the main point of the tool during processing to cut the tool edge. It can be used for applications such as cooling of chips and chip discharge in drilling. In addition, when the cleaning tool 10 is mounted on the main shaft 1 as shown in FIG. 2, the second fluid circuit 7 is connected to the air central hole 11 provided in the cleaning tool 10 so that the air is removed during the cleaning process. Can be injected.

  As shown in FIG. 1, the cleaning tool 10 as a tool attached to the main shaft 1 is provided with a tapered shank portion 12. The taper of the shank portion 12 has the same inclination as the taper of the mounting hole 3 of the main shaft 1. Although the cleaning tool 10 shown in FIG. 1 does not have a blade, a disk part 13 is provided at the front part of the shank part 12. There is a flange 14 on the main shaft 1 side of the disk portion 13, and when the cleaning tool 10 is mounted on the main shaft 1 as shown in FIG. 2, there is a gap between the end surface 15 of the flange 14 and the end surface 2 of the main shaft 1. A gap S having a dimension of 3 mm or more is formed.

  As shown in FIG. 3, in order to insert the cleaning tool 10 into the mounting hole 3 of the main shaft 1 and fix it, a fixing key 16 provided protruding from the main shaft 1 is used (in FIGS. 1 and 2). , Key 16 is omitted.) The keys 16 are provided at two positions 180 degrees apart in the circumferential direction, and are inserted into the respective key grooves of the cleaning tool 10 (in FIG. 1 and FIG. 2, the key grooves are not shown). As a result, the cleaning tool 10 is fixed to the main shaft 1.

  As shown in FIG. 1, the cleaning tool 10 is formed with a central hole 11 along the central axis thereof. The center hole 11 opens at the end of the shank portion 12 on the small diameter side, extends to the disk portion 13 along the center axis, and is formed in the disk portion 13 along the radial direction and tilted backward. The plurality of radiation holes 17 are branched. The plurality of radiation holes 17 are arranged at equiangular intervals along the circumferential direction of the disk portion 13. Each radiation hole 17 communicates with a plurality of second injection ports 18 arranged at equiangular intervals in the circumferential direction on the end surface 15 of the flange 14. Therefore, as shown in FIGS. 2 and 4, when the cleaning tool 10 is mounted on the main shaft 1, each second injection port 18 faces the end surface 2 of the main shaft 1 over the entire circumference.

  As shown in FIGS. 2 and 3, a long nozzle 20 for injecting coolant is provided above the main shaft 1 at the cleaning position in the machining chamber of the machining center. Two nozzles 20 are provided, and can be discharged at an arbitrary flow rate by receiving coolant from a main body (not shown). The diameter of the nozzle 20 is, for example, about 6 mm. However, if the flow rate is the same, a thinner nozzle is preferable because the momentum of coolant injection becomes stronger.

  The nozzle 20 is a flexible tubular body having a length of about several tens of centimeters, is connected to a coolant source of a main body (not shown), and is attached downward to the ceiling of the processing chamber. The nozzle 20 can arbitrarily adjust the bent shape of the long body, and can arbitrarily set the position and discharge direction of the tip. Specifically, the tip of the nozzle 20 is arranged at a position at least 1 cm away from the rotation locus of the main shaft 1 on which the cleaning tool 10 is mounted in consideration of safety. As an example, when the outer diameter of the main shaft 1 is 170 mm, the distance from the tip of the nozzle 20 to the center of the main shaft 1 is set to 100 mm. When the outer diameter of the main shaft 1 is 130 mm, the distance from the tip of the nozzle 20 to the center of the main shaft 1 is 80 mm. Furthermore, when the outer diameter of the main shaft 1 is 150 mm, the distance from the tip of the nozzle 20 to the center of the main shaft 1 is 90 mm.

  Further, the direction of the nozzle 20 is directed to the gap S between the flange 14 of the cleaning tool 10 and the main shaft 1 and the coolant is directly supplied to the end surface 2 of the main shaft 1 with the injection port slightly directed toward the main shaft 1 as shown in FIG. Set to be. Although the number of nozzles 20 is two, it may be one or three or more.

  The machining chamber of the conventional machining center may be provided with a nozzle for coolant. This is a short nozzle provided on the ceiling of the machining chamber, and several tens of centimeters to 1 meter or more from the spindle 1. Even if there is a gap S between the main shaft 1 and the cleaning tool 10, the coolant is not sprayed to hit the gap S and cannot be hit.

2. Cleaning Process When performing a normal tool change in such a machining center, as shown in FIG. 1, the tool is removed from the spindle 1 with an unillustrated changer, and then the first fluid circuit 6 from the air source of the main body is used. The air is supplied to the inside of the mounting hole 3 which is emptied by removing the tool. Even if chips or the like are contained in the mounting hole 3, it can be blown out.

  When the subsequent machining operation is a precision machining operation exceeding a certain standard, the end surface 2 of the main shaft 1 is cleaned using the cleaning tool 10, and then the next tool is attached. First, as shown in FIG. 1, a cleaning tool attaching step for attaching the cleaning tool 10 to the spindle 1 is performed using an attaching / detaching device (not shown) at a tool attaching / detaching position. Thereby, the positional relationship between the main shaft 1 and the cleaning tool 10 is the same as that shown in FIG. 2, and a gap S of 3 mm or more is provided between the end surface 15 of the flange 14 of the cleaning tool 10 and the end surface 2 of the main shaft 1. Occurs. Since this gap S is for the convenience of a cleaning process performed later by spraying the coolant onto the end surface 2 of the main shaft 1, 3 mm is the minimum, and in practice it is preferably 5 mm or more, and there is no particular upper limit.

Thereafter, as shown in FIGS. 2 and 3, the spindle 1 equipped with the cleaning tool 10 is moved to the cleaning position, and the next cleaning process is executed.
First, while discharging the coolant from the nozzle 20 and supplying the coolant into the gap S, the spindle 1 is rotated at a rotation speed of 100 revolutions per minute or less, and the foil-like chips stuck to the end surface 2 of the spindle 1 are removed. It is made to peel and it removes by flying with a centrifugal force (1st coolant washing | cleaning process). Note that the end surface 2 of the main shaft 1 is not a flat surface over the entire circumference. As described above, there is a portion where the key 16 for fixing the cleaning tool 10 protrudes from the end surface 2, and when this rotates at high speed, there is a gap. Since the coolant supplied in S is ejected out of the gap S, the rotation speed is preferably 100 revolutions per minute as described above, and more preferably 50 revolutions per minute. However, if the rotational speed is too small, it becomes difficult to obtain the cleaning effect by the rotation, so at least 30 revolutions per minute is necessary. The cleaning time is at least 10 seconds.

  Next, the rotation of the main shaft 1 is stopped, and the main shaft 1 is rotated in the direction opposite to the first coolant cleaning step at a rotation speed of 100 rotations per minute or less while supplying the coolant discharged from the nozzle 20 into the gap S. The foil-like chips stuck to the end face 2 of the main shaft 1 are peeled off and removed by centrifugal force (second coolant cleaning step). In this case, the number of rotations is preferably 100 or less per minute for the same reason, and more preferably 50 or less per minute, but at least 30 or more is necessary. The cleaning time is at least 10 seconds as in the case of normal rotation.

  In addition, it is preferable that the flow volume of the coolant supplied while rotating the main shaft 1 forward and backward is 3 liters or more in total.

  By such first and second coolant cleaning steps in which the rotation direction of the main shaft 1 is different, the foil-like chips attached to the end surface 2 of the main shaft 1 can be effectively peeled off and removed. In addition, when the end surface 2 of the main shaft 1 has a portion in which a key 16 for fixing the cleaning tool 10 protrudes and the main shaft 1 is rotated in only one direction during cleaning, the main shaft 1 There is a possibility that an area where it is difficult to obtain a cleaning effect due to the absence of coolant on one side of the end face 2 near the protruding key 16 may occur. However, in the embodiment, as described above, since the coolant cleaning is performed by changing the rotation direction, there is no such fear, and a sufficient cleaning effect can be obtained on both sides of the key 16 with respect to the rotation direction of the main shaft 1.

  When the coolant washing process performed by changing the rotation direction of the main shaft 1 and supplying the coolant is finished, the injection of the coolant from the nozzle 20 is stopped. Next, as shown by an imaginary line in FIG. 3, in order to avoid coolant dripping from the nozzle 20, the main shaft 1 is moved from the cleaning position to the tool attaching / detaching position or other position that is adjacent to the X direction.

  Here, a parallel air flow cleaning process using air flowing in the center direction along the end surface 2 of the main shaft 1 is performed. As shown in FIG. 5, air is supplied to the first fluid circuit 6 from an air source of the main body (not shown). This air is injected from the first injection port 8 and hits the back side of the eaves member 19, changes its direction downward by 90 degrees, flows along the end surface 2 of the main shaft 1, and cleans the end surface 2 of the main shaft 1. At this time, the main shaft 1 is rotated at 30 to 100 revolutions per minute, preferably 50 revolutions, so that the centrifugal force due to the rotation acts on the chips simultaneously with the air injection force. The air pressure is 0.45 to 0.55 MPa, preferably 0.5 MPa. The first air cleaning time is at least 10 seconds. The remainder of the foil-like chips from which at least a portion has been removed by the first and second coolant cleaning is removed, and the end surface 2 of the main shaft 1 is in a clean state.

  Next, the second cleaning with air is performed (cleaning tool air cleaning step). As shown in FIG. 4, air supplied from an air source on the main body (not shown) enters the central hole 11 of the cleaning tool 10 from the second fluid circuit 7 of the main shaft 1, passes through the radial hole 17, and the flange of the disk portion 13. 14 is sprayed from the second injection port 18 opened to 14 and sprayed to the entire end surface 2 of the main shaft 1. At this time, the main shaft 1 is rotated at 800 to 1200 revolutions per minute, preferably at 1000 revolutions per minute, so that the chips separated by the air are blown away by centrifugal force and removed. The air pressure is 0.5 MPa. The time for the second air cleaning is at least 10 seconds. Even after the first and second coolant cleaning and the parallel air flow cleaning process, even if foil-like chips still remain on the end surface 2 of the main shaft 1, this final cleaning tool air All the residue of the foil-like chips is removed by the cleaning process, and the end surface 2 of the main shaft 1 is completely clean.

  As described above, according to the embodiment, the cleaning tool 10 is attached by providing a clearance S of 3 mm or more on the end surface 2 of the main shaft 1, and the coolant is supplied to the clearance S so that the coolant is directly applied to the end surface 2 of the main shaft 1. The coolant cleaning process of rotating the main shaft 1 while applying was performed in two directions with different rotation directions. Further, while the main shaft 1 was rotated, a parallel air flow cleaning step by an air flow parallel to the end surface 2 of the main shaft 1 and a cleaning tool air cleaning step in which air was blown onto the end surface 2 of the main shaft 1 were performed. For this reason, even if the chips that have become foil-like due to compression due to the mounting of the tool are firmly attached to the end surface 2 of the main shaft 1, they can be completely removed.

3. Comparative Example The inventors of the present application have studied various cleaning apparatuses and cleaning methods for removing foil-like chips adhering to the end face 2 of the main shaft 1 before conceiving the present invention. Next, these studied cleaning methods will be described and compared with the present invention or the present embodiment.
(1) Using a commercially available cleaning tool, cleaning was performed by a method of spraying air from the inside of the main shaft from the nozzle of the cleaning tool and blowing it onto the end face of the main shaft. Since this is a conventional cleaning tool that is commercially available, only a gap of about 1 mm can be formed between the end surface of the main shaft and the cleaning tool. The rotation speed of the main shaft is 1000 rpm, the air pressure is 0.5 MPa, and the time is 30 seconds. Air did not sufficiently enter the narrow gap, and foil-like chips could not be removed from the end face of the main shaft.

  (2) Using the same cleaning tool as in (1) above, cleaning was performed by spraying coolant instead of air and spraying it onto the end face of the main shaft. The rotation speed of the main shaft is 1000 revolutions per minute, the coolant discharge amount is 10 L / min, the discharge pressure is 3 MPa, and the time is 30 seconds. There was not enough coolant in the narrow gap of about 1 mm between the end surface of the main shaft and the conventional cleaning tool, and foil-like chips could not be removed from the end surface of the main shaft.

  (3) In the conventional machining center, the main shaft according to the above (1) while the coolant is discharged from the conventional short coolant nozzle provided on the ceiling of the processing chamber and applied to the vicinity of the end of the main shaft several centimeters away from the nozzle. Rotation and air injection. In this method, the coolant is not sufficiently distributed in the narrow gap between the cleaning tool and the end surface of the main shaft, and air is not sufficiently input, so that the foil-like chips can be removed from the end surface of the main shaft. There wasn't.

DESCRIPTION OF SYMBOLS 1 ... Main shaft 2 ... End surface of main shaft 8 ... 1st injection port 10 ... Cleaning tool 11 ... Center hole 18 ... 2nd injection port 20 ... Nozzle for supplying coolant S ... Gap

Claims (1)

After the cleaning tool mounting step of mounting the cleaning tool on the main shaft such that a gap of 3 mm or more is generated between the end surface of the main shaft of the machining center,
A first coolant cleaning step of rotating the spindle at a rotation speed of 100 revolutions per minute or less while supplying coolant into the gap;
A second coolant cleaning step of rotating the main shaft in a direction opposite to the rotation direction of the first coolant cleaning step at a rotation speed of 100 rpm or less while supplying the coolant into the gap;
Have
And a cleaning tool air cleaning step of rotating the main shaft while blowing air to the end face from an injection hole opened on the opposite surface of the cleaning tool facing the end face across the gap. Cleaning method for the end face of the main shaft.

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