JP5882104B2 - Machine Tools - Google Patents

Description

  The present invention relates to a machine tool on which a tool or an attachment is mounted on a spindle.

  A conventional machine tool is a collet that holds a pull stud bolt (hereinafter referred to as a pull stud) provided at the tip of a tool holder or the tip of an attachment adapter in order to detachably attach a tool or attachment to the spindle of the machine tool. And a draw bar for releasing the holding of the pull stud by the collet. The collet and the draw bar are arranged so as to be movable in the axial direction inside the main shaft.

  Specifically, a tool mounting portion into which a tool holder or an attachment adapter can be inserted is formed at the end of the main shaft. Further, a central through hole penetrating in the axial direction is formed inside the main shaft. The central through hole communicates with the tool mounting portion.

  The collet includes a pull stud that is a held portion of a tool holder or an adapter of an attachment and a plurality of claws that can be held. The collet is disposed so as to be movable in the axial direction inside the tool mounting portion and the central through hole inside the main shaft. The collet holds the pull stud when moving from the tool mounting portion toward the central through hole, and releases the pull stud when moving from the central through hole to the tool mounting portion.

  The draw bar is a rod-like body that is disposed in the central through-hole so as to be movable in the axial direction and that performs a push-pull operation of the collet. A collet is connected to the end of the draw bar on the tool mounting portion side (so-called front end). The end (the so-called rear end) of the draw bar opposite to the tool mounting portion side protrudes outside the main shaft.

  The draw bar is always urged in a direction from the tool mounting portion toward the central through hole by a spring provided inside the main shaft. When the rear end portion of the draw bar is pushed in the direction toward the tool mounting portion by a hydraulic cylinder or the like, the draw bar pushes the collet toward the tool mounting portion and releases the holding of the pull stud by the collet. On the other hand, when the urging force from the hydraulic cylinder disappears, the draw bar is pushed back from the tool mounting portion to the central through hole by the restoring force of the spring. Thereby, the collet is returned to the central through hole together with the draw bar, thereby making it possible to hold the pull stud.

  In a machine tool equipped with such a collet and drawbar, the holding state of the pull stud by the collet cannot be visually recognized from the outside. Therefore, the holding state of the pull stud by the collet is determined by the position of the draw bar. For example, in the machine tool described in Patent Document 1, a probe is installed at a position where it can come into contact with an end surface (hereinafter referred to as a rear end surface) opposite to the tool mounting portion side of the draw bar. The position of the draw bar is detected by bringing this probe into contact with the rear end surface of the draw bar, and the control unit of the machine tool determines whether or not the draw bar position is the normal return position. Determine. For example, when the collet is correctly holding the pull stud, the collet is correctly drawn into the central through hole, and the draw bar moves to the normal return position, so that the probe detects the position of the rear end surface of the draw bar. It can be determined that the pull stud holding state by the collet is normal. On the other hand, when the collet does not hold the pull stud correctly, for example, when it is in a half-gripping state, the drawbar is positioned closer to the tool mounting part than the normal return position because the collet is not correctly drawn into the center through hole. Stop at. When the probe detects the position of the draw bar, it can be determined that the holding state of the pull stud by the collet is abnormal.

JP 2005-319540 A

  However, in the machine tool described in Patent Document 1, the probe for detecting the position of the draw bar is arranged at a position where it can contact the rear end surface of the draw bar, and the position of the draw bar is detected by the probe contacting the rear end surface of the draw bar. Therefore, if the main shaft is long, the distance between the probe and the collet may be increased and it may be difficult to accurately determine the holding state of the pull stud by the collet.

  For example, if the main shaft becomes longer as the machine tool becomes larger, the draw bar inside the main shaft also needs to be longer. If the draw bar becomes longer, the influence of the deflection or elongation of the draw bar increases, and there is a possibility that the displacement between the displacement amount of the rear end surface of the draw bar and the displacement amount of the collet becomes larger. Therefore, it becomes difficult to accurately determine the holding state of the pull stud by the collet.

  Further, the draw bar is a rod-like body having a diameter smaller than that of the main shaft, and it is difficult to integrally form the draw bar having a small diameter. For this reason, when the size of the machine tool is increased, a plurality of drawbars that are not connected may be arranged inside the main shaft, and the collet may be pushed by the plurality of drawbars. In this case, even if the amount of movement of the draw bar is detected on the rear end surface of the last draw bar, there is a possibility that it does not coincide with the amount of movement of the collet, so it is difficult to accurately determine the holding state of the pull stud by the collet. .

  The present invention has been made in view of the above circumstances, and provides a machine tool capable of accurately determining the holding state of a tool holder or an adapter of an attachment without being affected by an increase in the length of a spindle. The purpose is to provide.

A machine tool according to a first aspect of the present invention includes a peripheral wall that surrounds a central through hole extending along a central axis, and a tool mounting portion that communicates with the central through hole and has a shape on which a tool holder or an attachment adapter can be mounted. And a tool shaft or a holder to be held by the attachment adapter when retracted from the tool mounting portion to the central through hole. A holding portion having a structure in which holding from the held portion is released when the tool is moved forward from the central through hole, and is arranged movably along the central axis inside the central through hole, An operation shaft connected to the holding portion and performing an operation of moving the holding portion into and out of the tool mounting portion from the central through hole, and the operation shaft in a direction in which the central axis extends. An operating shaft drive unit to be moved, a detected object connected to the operating shaft, and an operating shaft position detection sensor that detects the position of the operating shaft by detecting the position of the detected object. The main shaft has a peripheral wall side through hole that penetrates the peripheral wall and communicates the central through hole and the peripheral wall outside, and the detected object is exposed to the outside through the peripheral wall side through hole in the operation shaft. The peripheral wall side through-hole is equal to or greater than the amount by which the operation shaft moves between a holding state where the holding portion holds the held portion and a holding release state where the holding is released. The operation shaft position detection sensor is disposed outside the peripheral wall, and the operation shaft includes a first shaft member and a second shaft. A first shaft member and a shaft member. The second shaft member is arranged inside the central through hole of the main shaft in a state where the ends of the first shaft member and the second shaft member are in contact with each other, and the first shaft member is the second shaft member. It is arranged at a position closer to the holding part than the shaft member and is connected to the holding part, and the detected body is connected to a portion exposed to the outside through the peripheral wall side through hole in the first shaft member, The operation shaft drive unit includes a retreat drive unit for retreating the first shaft member in a direction away from the tool mounting unit, and a forward drive unit for advancing the second shaft member in a direction approaching the tool mounting unit. and said that you are.

  In the present invention, instead of detecting the position of the operation shaft such as a draw bar at the rear end surface of the operation shaft, a peripheral wall side through hole is formed in the peripheral wall of the main shaft, and the portion exposed to the outside through the peripheral wall side through hole in the operation shaft By performing the position detection at, it is possible to detect the position of the operation axis at a position closer to the holding unit.

  In other words, the detected object detected by the operation shaft position detection sensor is connected to a portion exposed to the outside through the peripheral wall side through hole in the operation shaft, and the operation shaft position detection sensor detects the position of the detected object from the outside of the peripheral wall. I can do it.

Moreover, the peripheral wall side through hole that opens in the radial direction of the main shaft has an opening width that is larger than the amount by which the operation shaft moves between the holding state and the holding release state of the holding portion. The detected object can move in the axial direction of the main shaft without the connecting portion of the operation shaft and the detected object or the detected object interfering with the main shaft. With such a configuration, it becomes possible to arrange the detected object outside or inside the peripheral wall of the main shaft, which could not be arranged in the past, and thereby arrange it at a position closer to the holding part than the rear end surface of the operation shaft. Is possible. Therefore, it is possible to accurately detect the displacement amount of the operation shaft without being affected by the length of the main shaft, and as a result, it is possible to accurately determine the holding state of the held portion by the holding portion. Thus, the reliability of the determination of the holding state is improved.
Moreover, according to said structure, an operating shaft is provided with the 1st shaft member and the 2nd shaft member, and these shaft members are arranged side by side in the center through-hole of a main axis | shaft in the state which faced each edge part. Has been. The retraction drive unit of the operation shaft drive unit retreats the first shaft member in the direction away from the tool mounting unit, so that the second shaft member is pushed and retreated by the first shaft member. The shaft member can be moved backward together. Further, since the advance drive unit of the operation shaft drive unit advances the second shaft member in a direction to approach the tool mounting unit, the first shaft member is pushed forward by the second shaft member, and thus the first shaft member and The second shaft member can move forward integrally. In such a configuration, the object to be detected is connected to the first shaft member that is the shaft member closer to the holding unit and is connected to the holding unit. Even if the size is increased, the displacement of the first shaft member to which the holding portion is connected can be accurately detected without being affected by the increase in length. As a result, it is possible to more accurately determine the holding state of the holding unit.

  The operation axis position detection sensor generates a magnetic field and detects the position of the detected object by detecting impedance due to the eddy current generated by the detected object, and the detected object receives the magnetic field. It is preferable that the object to be detected has a protrusion that protrudes in a direction away from the peripheral wall outside the peripheral wall of the main shaft.

  According to this configuration, the position of the detection target can be accurately detected using the magnetic field while suppressing the influence from the main axis.

  Here, when a sensor that detects the position of the detected object by detecting impedance due to eddy current generated inside the detected object that has received a magnetic field is used as the operation axis position detection sensor, If the distance from the peripheral wall is short, there is a possibility that the impedance due to the eddy current generated in the detection target cannot be accurately detected due to the influence of the impedance due to the eddy current generated in the peripheral wall.

  Therefore, according to the above configuration, since the detected body has a protruding portion protruding in a direction away from the peripheral wall, it becomes possible to reduce the distance between the sensor and the protruding portion of the detected body, It is possible to accurately detect the impedance due to the eddy current generated in the detection target while suppressing the influence of the impedance due to the eddy current generated in the peripheral wall, and it is possible to more accurately detect the displacement amount of the operation shaft.

  Further, the operation axis position detection sensor has a configuration capable of detecting the movement amount of the operation axis, and based on the movement amount of the operation axis, a holding state of the held portion by the holding portion It is preferable to further include a holding state discriminating unit for discriminating the above.

  When the holding part correctly holds the held part, the operating shaft is in a predetermined position corresponding to the normal holding state, but in the incomplete holding state, for example, in the half-gripping state, Stop at a different position. Therefore, in the above configuration, the position detection sensor quantitatively detects the movement amount of the operation shaft, and based on this, the holding state determination unit can more accurately determine the holding state.

According to a fourth aspect of the present invention, there is provided a machine tool including a peripheral wall surrounding a central through hole extending along a central axis, and a tool mounting portion communicating with the central through hole and having a shape capable of mounting a tool holder or an attachment adapter. And a tool shaft or a holder to be held by the attachment adapter when retracted from the tool mounting portion to the central through hole. A holding portion having a structure in which holding from the held portion is released when the tool is moved forward from the central through hole, and is arranged movably along the central axis inside the central through hole, An operation shaft connected to the holding portion and performing an operation of moving the holding portion into and out of the tool mounting portion from the central through hole, and the operation shaft in a direction in which the central axis extends. Receiving an operating shaft drive unit for moving the object to be detected which is connected to the operating shaft, a control shaft position sensor for detecting a position of the operating shaft by detecting a position of the detection object, said spindle A storage member that holds the main body of the attachment to the storage member, and an attachment holding portion that releases the hold, an attachment position detection sensor that detects a position of the main body of the attachment relative to the storage member, and the operation shaft based on the location and position of the body of the attachment comprises an abnormality discriminating unit for discriminating abnormality of the mounting of the attachment at the time when the body of the attachment and held in the housing member, the spindle, the peripheral wall Through the central through hole and the peripheral wall outside through the peripheral wall side through hole, the detected object is, The operation shaft is connected to a portion exposed to the outside through the peripheral wall side through hole, and the peripheral wall side through hole is in a holding state in which the holding portion holds the held portion and a holding release in which the holding portion is released. An opening width in a direction in which the central axis extends is larger than the amount by which the operation shaft moves between states, and the operation shaft position detection sensor is disposed outside the peripheral wall. It is characterized by.

When connecting the adapter of the attachment to the main shaft, the main body of the attachment is held by a storage member such as a ram for storing the main shaft in the machine tool by the attachment holding portion. Here, even if the position of the attachment main body with respect to the storage member is in the normal position, when the held portion of the attachment adapter is not normally held by the holding portion, for example, the attachment may be in a half-gripping state. . On the other hand, even if the held portion of the attachment adapter is normally held by the holding portion, the position of the attachment main body relative to the storage member may not be a normal position. In these cases, there is a possibility that an abnormality in attachment attachment, for example, a problem such as dropping of the attachment during indexing turning may occur. Therefore, according to the above configuration, the abnormality determination unit can determine an abnormality in attachment attachment at the time of attachment attachment based on the position of the operation shaft and the position of the attachment. Thereby, for example, before indexing the attachment, even if the position of the main body of the attachment with respect to the storage member is in a proper position, it is possible to determine in advance the abnormality in the holding state of the held portion by the holding portion Thus, it is possible to reduce the risk of the attachment falling during indexing turning.
Further, according to the above configuration, as in the invention according to claim 1 of the present application, instead of detecting the position of the operation shaft such as the draw bar on the rear end surface of the operation shaft, the peripheral wall side through-hole is formed in the peripheral wall of the main shaft. In addition, the position of the operation shaft can be detected at a position closer to the holding portion by performing position detection at a portion of the operation shaft exposed to the outside through the through hole on the peripheral wall side. In other words, the detected object detected by the operation shaft position detection sensor is connected to a portion exposed to the outside through the peripheral wall side through hole in the operation shaft, and the operation shaft position detection sensor detects the position of the detected object from the outside of the peripheral wall. I can do it. Moreover, the peripheral wall side through hole that opens in the radial direction of the main shaft has an opening width that is larger than the amount by which the operation shaft moves between the holding state and the holding release state of the holding portion. The detected object can move in the axial direction of the main shaft without the connecting portion of the operation shaft and the detected object or the detected object interfering with the main shaft. With such a configuration, it becomes possible to arrange the detected object outside or inside the peripheral wall of the main shaft, which could not be arranged in the past, and thereby arrange it at a position closer to the holding part than the rear end surface of the operation shaft. Is possible. Therefore, it is possible to accurately detect the displacement amount of the operation shaft without being affected by the length of the main shaft, and as a result, it is possible to accurately determine the holding state of the held portion by the holding portion. Thus, the reliability of the determination of the holding state is improved.

  Further, the detected body has a contact surface that contacts an outer peripheral surface of the peripheral wall of the main shaft, and the detected object is in a state where the contact surface is in contact with an outer peripheral surface of the peripheral wall of the main shaft. It is preferable to support the operating shaft.

  According to such a configuration, the detection object can function to support the operation shaft when the contact surface of the detection body contacts the outer peripheral surface of the peripheral wall of the main shaft. Thereby, it is possible to prevent problems such as the operation shaft deviating from the axis of the main shaft.

  Furthermore, it is preferable that the detected body has a symmetrical shape with respect to the axial center of the main shaft.

  According to such a configuration, the object to be detected has a symmetric shape (for example, a disk shape) with respect to the axial center of the main shaft, so that it is possible to suppress a decrease in the rotation balance of the operation shaft.

  As described above, according to the present invention, it is possible to accurately determine the holding state of the held portion by the holding portion without being affected by the length of the main shaft.

It is sectional drawing of the spindle vicinity of the machine tool concerning embodiment of this invention. It is an arrow A view of the main axis | shaft and ram of FIG. FIG. 2 is a cross-sectional view around a lower end portion of a main shaft in FIG. 1. FIG. 2 is a cross-sectional view of an operation axis position detection sensor and a detected object periphery in FIG. 1. It is sectional drawing which shows the state in which the adapter of the attachment was inserted with respect to the tool mounting part of the main axis | shaft of FIG. 1, and the collet is open. It is sectional drawing which shows the state which the draw bar of FIG. 5 raises and the collet is hold | maintaining normally with respect to a pull stud. It is sectional drawing which shows the state which clamped the main body of the attachment of FIG. 6 to the ram. It is sectional drawing which shows the state which the collet of FIG. 4 hold | maintains in the state of half-gripping with respect to the pull stud. It is a perspective view of the adapter of the attachment of FIG. It is a block diagram which shows the structure of the control part of FIG.

  Next, the machine tool of the present invention will be described in more detail with reference to the drawings.

  1 to 4 includes a main shaft 2, a ram 3 that houses the main shaft 2, a main shaft clamp mechanism 4, an attachment clamp mechanism 5, a draw bar position detection mechanism 6, and an attachment position detection mechanism 7. And. In the machine tool 1, the main shaft 2 and the ram 3 are arranged extending in the vertical direction.

  In the machine tool 1, the adapter 51 of the attachment 50 is attached to the spindle 2 by the spindle clamp mechanism 4. The attachment body 53 is fixed to the ram 3 by the attachment clamp mechanism 5.

  Here, the attachment 50 attached to the machine tool 1 will be briefly described. As shown in FIG. 3, the attachment 50 includes an adapter 51, a pull stud 52 provided at the tip of the adapter 51, an attachment main body 53, a carbide gear 54, an attachment pin 56, and a vertical direction inside the attachment main body 53. And an attachment main shaft (not shown).

  The adapter 51 is attached to the upper end of the attachment main shaft inside the attachment main body 53 so that the adapter 51 can rotate around the central axis C of the main shaft 2 with respect to the attachment main body 53. The adapter 51 is spline-coupled to the attachment main shaft inside the attachment main body 53 so that it can be moved in the direction of the central axis C in the vertical direction independently of the attachment main body 53, and is always attached upward by a spring (not shown). It is energized.

  The adapter 51 has a conical shape as shown in FIGS. 3 and 9, and a pull stud 52 is provided at the tip of the adapter 51 as a held portion held by the collet 12 of the spindle clamping mechanism 4. It has been. The pull stud 52 includes a shaft portion 52a and a head portion 52b projecting in the radial direction of the shaft portion 52a provided at the tip of the shaft portion 52a. The adapter 51 also has a pair of key holes 51a into which the main shaft end key 2c4 at the lower end of the main shaft 2 can be inserted. The clutch pin 51c (see FIGS. 5 and 9) is provided so as to protrude upward at a position away from the pull stud 52 in the adapter 51.

  As shown in FIG. 5, in a state before the attachment main body 53 is fixed to the ram 3 (for example, a state when the attachment 50 is prepared for clamping), the clutch pin 51c (see FIGS. 5 and 9) of the adapter 51 is The adapter 51 and the attachment main body 53 are inserted into the insertion hole 57 of the attachment main body 53, and can be indexed and swiveled around the central axis C in a state where they are coupled via the clutch pin 51c. . On the other hand, in the state where the attachment main body 53 is fixed to the ram 3 as shown in FIG. 7, the clutch main body 53 is pulled up by the attachment holding portion 25, so that the clutch pin 51 c is lowered from the insertion hole 57 of the attachment main body 53. I'm slipping out. In this state, since the coupling between the adapter 51 and the attachment main body 53 via the clutch pin 51c is released, the adapter 51 can turn around the central axis C alone.

  Next, each part of the machine tool 1 will be described in detail.

  The main shaft 2 has a peripheral wall 2b surrounding a central through hole 2a extending along the central axis C in the vertical direction, and a tool mounting portion 2c provided at the lower end of the peripheral wall 2b.

  Further, the main shaft 2 has a peripheral wall side through hole 2d that penetrates the peripheral wall 2b and communicates the central through hole 2a and the outer periphery of the peripheral wall 2b.

  The peripheral wall side through hole 2d has an operation shaft 13 (specifically, the first draw bar 16) described later between a holding state in which the collet 12 holds the pull stud 52 and a holding release state in which the holding is released. ) Has an opening width W in the direction in which the central axis C extends in a direction larger than the moving amount.

  The tool mounting portion 2c has a shape that allows the adapter 51 of the attachment 50 to be mounted. The tool mounting portion 2c has a space portion 2c1 that opens downward so that the conical adapter 51 can be inserted.

  The space 2c1 extends in a conical shape of the adapter 51 and is formed at an adapter storage portion 2c2 in which the adapter 51 is stored, and at the tip of the conical portion 2c2. The collet 12 opens and closes to hold the pull stud 52 and to hold the pull stud 52. And a collet opening / closing portion 2c3 for releasing. The collet opening / closing part 2c3 communicates with the central through hole 2a. The inner diameter of the collet opening / closing portion 2c3 is set to be larger than the inner diameter of the central through hole 2a so that the collet 12 can be opened and closed to perform the operation of holding the pull stud 52 and releasing the holding.

  When the adapter 51 is normally stored in the adapter storage portion 2c2, the outer peripheral surface of the adapter 51 can contact the inner peripheral surface of the adapter storage portion 2c2. When the adapter 51 is normally stored in the adapter storage portion 2c2, the shaft portion 52a of the pull stud 52 is positioned at the collet opening / closing portion 2c3. When the shaft portion 52a is in this position, the collet 12 opens and closes to sandwich the shaft portion 52a of the pull stud 52, so that the collet 12 is engaged with the head portion 52b at the tip of the shaft portion 52a. It is possible to hold

  The tool mounting portion 2c includes a spindle end key 2c4 at the lower end thereof. The spindle end key 2c4 is composed of a pair of protrusions arranged on both sides of the space 2c1. The spindle end key 2 c 4 has a shape that can be inserted into the key hole 51 a of the adapter 51.

  The ram 3 is a cylinder that rotatably stores the main shaft 2 and corresponds to the storage member of the present invention. The ram 3 has a space 3 a that houses the main shaft 2. The main shaft 2 is supported on the inner wall of the space 3 a of the ram 3 via a bearing 11 so as to be rotatable around the central axis C.

  A ring-shaped carbide gear 61 for indexing the attachment 50 is provided at the lower end of the ram 3. The carbide gear 61 has a plurality of teeth 61a protruding downward. The plurality of teeth 61a are arranged at equal intervals in a circumferential shape. When the attachment main body 53 of the attachment 50 is attached to the lower end of the ram 3, the carbic gear 61 can mesh with the carbic gear 54 provided on the upper end side of the attachment main body 53.

  The main shaft 2 and the ram 3 can be moved in the horizontal direction and the vertical direction by a moving mechanism (not shown).

  The main shaft clamp mechanism 4 is provided on the main shaft 2. The spindle clamping mechanism 4 is a mechanism that holds the adapter 51 so as to be fixed to the tool mounting portion 2c and releases the holding. Specifically, the spindle clamping mechanism 4 includes a collet 12 that holds the pull stud 52 of the adapter 51, an operation shaft 13 that pushes and pulls the collet 12, and an operation shaft drive unit. The collet 12 corresponds to the holding unit of the present invention.

  The collet 12 is attached to the tip of the operation shaft 13 so as to be able to protrude and retract from the central through hole 2a to the tool mounting portion 2c. As shown in FIGS. 2 to 3, the collet 12 is coupled to the fixing portion 12 a so as to be openable and closable, and a cylindrical fixing portion 12 a that is fixed to a distal end of a first draw bar 16 to be described later that constitutes the operation shaft 13. The four tongue pieces 12b, the claw portions 12c provided at the tips of the tongue pieces 12b, and the four tongue pieces 12b are urged away from the central axis C of the main shaft 2 (that is, in the opening direction). And a spring 12d (see FIG. 3). The claw portion 12 c has a shape that can be engaged with the head portion 52 b of the pull stud 52. The tongue piece 12b can move in the radial direction of the main shaft 2 (that is, the direction approaching and leaving the center axis C).

  When the collet 12 receives an operation force from the operation shaft 13 and retreats from the tool mounting portion 2c to the central through hole 2a, each tongue piece 12b is pushed against the inner wall of the central through hole 2a of the main shaft 2, and the spring 12d. The claw portion 12c moves in a direction approaching the central axis C while resisting the urging force. As a result, the claw portion 12 c can hold the pull stud 52 of the adapter 51 of the attachment 50. Further, when the collet 12 moves forward from the central through hole 2a to the tool mounting portion 2c, the claw portion 12c of each collet 12 protrudes from the central through hole 2a of the main shaft 2 to the collet opening / closing portion 2c3 having a larger inner diameter than the central through hole 2a. The tongue 12b of the collet 12 moves away from the central axis C by the restoring force of the spring 12d. Thereby, the nail | claw part 12c leaves | separates from the pull stud 52, and the holding | maintenance of the said pull stud 52 is cancelled | released.

  The operation shaft 13 is disposed inside the central through hole 2a so as to be movable along the central axis C, and performs an operation of projecting and retracting the collet 12 from the central through hole 2a to the tool mounting portion 2c.

  Specifically, the operation shaft 13 includes a first draw bar 16 and a second draw bar 17. The first draw bar 16 and the second draw bar 17 are arranged side by side inside the central through hole 2a of the main shaft 2 with the upper end portion 16b of the first draw bar 16 and the lower end portion 17a of the second draw bar 17 abutting each other. .

  The first draw bar 16 is disposed closer to the collet 12 than the second draw bar 17 and is connected to the collet 12.

  The lower end 16a of the first draw bar 16 has a recess 16c extending in the circumferential direction of the lower end 16a. The fixing portion 12a of the collet 12 is fitted into the recess 16c. Thereby, the collet 12 is fixed to the lower end portion 16a of the first draw bar 16 so that the pull stud 52 can be held and released from the lower end portion 16a of the first draw bar 16.

  The operation shaft drive unit moves the operation shaft 13 in the direction in which the central axis C extends. The operation shaft drive unit includes a reverse drive unit 18 and a forward drive unit. The reverse drive unit 18 retracts the first draw bar 16 in a direction away from the tool mounting unit 2c. The advance drive unit advances the second draw bar 17 in a direction to approach the tool mounting unit 2c.

  The forward drive unit includes a hydraulic cylinder 19 that pushes the second draw bar 17 toward the tool mounting unit 2c.

  Specifically, the backward drive unit 18 includes a plurality of stacked leaf springs 18a, a first washer 18b, a second washer 18c, and a washer presser 18d. The first washer 18b is sandwiched between the lowermost leaf spring 18a and the stepped portion 2e inside the central through hole 2a in the main shaft 2. The washer presser 18 d is fixed at a position near the upper end portion 16 b of the first draw bar 16. The second washer 18c is sandwiched between the uppermost plate spring 18a and the washer retainer 18d. When the first draw bar 16 receives the pressing force from the hydraulic cylinder 19 via the second draw bar 17, the first draw bar 16 descends while compressing the plurality of leaf springs 18a, and the lower end 16a of the first draw bar 16 The collet 12 attached to is pushed out to the space portion 2c1 of the tool mounting portion 2c. On the other hand, when the pressing force from the hydraulic cylinder 19 disappears, the first draw bar 16 moves upward by the restoring force of the plurality of leaf springs 18a, so the collet 12 moves from the tool mounting portion 2c to the inside of the central through hole 2a. Be drawn.

  The draw bar position detection mechanism 6 is a detection unit that detects the holding state of the adapter 51 by the spindle clamping mechanism 4 by detecting the position of the draw bar. Specifically, the drawbar position detection mechanism 6 includes an operation axis position detection sensor 20 and a detected body 21 as shown in FIG.

  The operation shaft position detection sensor 20 detects the position of the operation shaft 13 by detecting the position of the detected object 21.

  Specifically, the operation axis position detection sensor 20 shown in FIG. 4 is a sensor that can detect the position of the detected object 21 without contacting the detected object 21, and a magnetic field (specifically, a high frequency magnetic field). And the position of the detected object 21 is detected by detecting the impedance (magnetic loss) due to the eddy current generated by the detected object 21.

  The operation shaft position detection sensor 20 includes a sensor main body 20 a and a bracket 20 b that fixes the sensor main body 20 a to the inner wall of the space 3 a of the ram 3.

  In the sensor body 20a, a plurality of high-frequency coils (not shown) are arranged along the direction in which the central axis C extends. The high frequency magnetic field generated from the plurality of high frequency coils is radiated to the outside of the sensor main body 20a from the radiation surface 20c facing the peripheral wall through hole 2d of the main shaft 2 in the sensor main body 20a. In this operation axis position detection sensor 20, an eddy current is generated in the detected object 21 by a high frequency magnetic field generated from a plurality of high frequency coils, and the amount of movement of the operation shaft 13 is reduced to 1 mm or less by detecting impedance due to the eddy current. Can be detected with a resolution of about 125 μm.

  The detected object 21 is detected by the operation axis position detection sensor 20. The detected object 21 is connected to a portion exposed to the outside through the peripheral wall side through hole 2 d in the first draw bar 16 constituting the operation shaft 13.

  Specifically, the detected body 21 includes a main body 21a, a bolt 21b that connects the main body 21a to the first draw bar 16, and an inner support member 21c. The main body 21 a is a symmetric shape with respect to the direction in which the central axis C of the main shaft 2 extends, for example, a ring-shaped member that surrounds the outer periphery of the main shaft 2. The main body 21a is connected to a portion exposed to the outside through the peripheral wall side through hole 2d in the first draw bar 16 by a bolt 21b penetrating the peripheral wall side through hole 2d.

  The main body 21 a has a contact surface 21 a 1 that contacts the outer peripheral surface of the peripheral wall 2 b of the main shaft 2. The main body portion 21 a supports the operation shaft 13 in a state where the contact surface 21 a 1 is in contact with the outer peripheral surface of the peripheral wall 2 b of the main shaft 2.

  The main body 21 a has a protruding portion 22 that protrudes in a direction away from the peripheral wall 2 b outside the peripheral wall 2 b of the main shaft 2. The protrusion 22 is disposed at a position facing the radiation surface 20c of the sensor body 20a of the operation axis position detection sensor 20 with a minute gap (about 2 mm). The operation axis position detection sensor 20 detects the position of the protrusion 22. In addition, since the length of the projecting portion 22 in the central axis C direction is set to be shorter than the length of the main body portion 21a, the operation shaft position detection sensor 20 accurately detects a minute change in the amount of movement of the projecting portion 22. It becomes possible to detect.

  The main body 21a of the detected body 21 includes a material capable of generating an eddy current when receiving a magnetic field (high frequency magnetic field) generated from the operation axis position detection sensor 20. For example, the detected object 21 is made of a metal material such as iron.

  The inner support member 21 c is attached near the upper end portion 16 b of the first draw bar 16. The inner support member 21c has a contact surface 21c1 that contacts the inner peripheral surface of the peripheral wall 2b of the main shaft 2 on the outer peripheral surface thereof.

  In the present embodiment, the detected object 21 is in contact with the outer peripheral surface and the inner peripheral surface of the peripheral wall 2b of the main shaft 2. Specifically, the contact surface 21a1 of the main body 21a contacts the outer peripheral surface of the peripheral wall 2b of the main shaft 2, and the contact surface 21c1 of the inner support member 21c contacts the inner peripheral surface of the peripheral wall 2b. As a result, it is possible to prevent the first draw bar 16 from being displaced from the central axis C inside the central through hole 2a of the main shaft 2.

  As shown in FIG. 3, the attachment clamp mechanism 5 includes an attachment holding part 25, a hydraulic cylinder 26, and a guide part 27. The attachment holding unit 25 holds the attachment main body 53 so as to be fixed to the ram 3, and releases the holding.

  The attachment holding part 25 is made of a collet having a claw part 25b1. The intermediate part of the attachment holding part 25 can move in the radial direction of the main shaft 2 (that is, the direction approaching and separating from the central axis C). The base side end portion 25 a of the attachment holding portion 25 is fixed to the downward extension portion 26 b 1 of the piston portion 26 b of the hydraulic cylinder 26. The distal end portion 25b of the attachment holding portion 25 has a claw portion 25b1 projecting toward the central axis C and a protruding portion 25b2 (see FIG. 3) protruding in the opposite direction to the claw portion 25b1. The claw portion 25b1 can be engaged with a stepped portion 55 provided in the carbide gear 54 or the like as a held portion in the attachment main body 53.

  The hydraulic cylinder 26 includes a cylinder portion 26a provided on the peripheral wall of the ram 3, and a piston portion 26b arranged to be movable up and down in the space portion 26a1 of the cylinder portion 26a. The compressed oil is fed into the space 26a1 above the upper end surface of the piston portion 26b, whereby the piston portion 26b and the attachment holding portion 25 can be lowered. On the other hand, it is possible to raise the piston part 26b and the attachment holding | maintenance part 25 by sending compressed oil to the part below the lower end surface of the piston part 26b among space part 26a1.

  The guide portion 27 has a guide surface 27a extending in the direction in which the central axis C extends. When the attachment holding part 25 rises, the protruding portion 25b2 of the tip part 25b of the attachment holding part 25 is pressed in a direction approaching the central axis C by the guide surface 27a. Thereby, in a state where the intermediate portion of the attachment holding portion 25 is moved in a direction approaching the central axis C, the attachment holding portion 25 is guided upward while maintaining a position where it can be engaged with the stepped portion 55 of the attachment main body 53. Is done.

  The attachment position detection mechanism 7 includes an attachment position sensor 28. The attachment position sensor 28 is a sensor that detects the position of the attachment main body 53 with respect to the ram 3. As the attachment position sensor 28, for example, a differential transformer type displacement sensor is used. Such an attachment position sensor 28 includes a probe 28a that comes into contact with the detected portion on the attachment main body 53 side, a coil portion 28b, and a core portion (not shown) connected to the upper end portion of the probe 28a.

  The coil part 28b includes a plurality of electromagnetic coils arranged coaxially, and has a space part in which the core part can move inside the electromagnetic coil. The coil portion 28b excites an AC voltage to a certain electromagnetic coil, and detects the voltage that changes depending on the position of the core portion moving inside the space portion by using another electromagnetic coil, whereby the core portion and the probe connected thereto It is possible to detect the position 28a.

  The probe 28 a shown in FIG. 3 is in contact with a detected portion on the attachment main body 53 side, specifically, an attachment pin 56 provided on the upper end surface of the attachment main body 53. Thereby, the position of the attachment 50 can be detected. The probe 28a and the coil portion 28b are arranged in order from the bottom in the insertion hole 3b of the attachment pin 56 formed on the lower end surface of the ram 3.

  When the attachment main body 53 is attached to the lower end surface of the ram 3, the attachment pin 56 is inserted into the insertion hole 3b, so that the probe 28a is pushed upward by the attachment pin 56. Therefore, the position of the attachment 50 depends on the position of the probe 28a. Can be detected.

  As shown in FIGS. 5 and 10, the machine tool 1 includes a control unit 31 such as a CPU that controls the overall operation of the machine tool 1. The control unit 31 includes a holding state determination unit 32 and an attachment abnormality determination unit 33.

  The holding state determination unit 32 determines the holding state of the pull stud 52 by the collet 12 based on the movement amount of the operation shaft 13 detected by the operation shaft position detection sensor 20.

  The attachment abnormality determination unit 33 determines the attachment abnormality of the attachment 50 when the attachment body 53 is held on the ram 3 based on the position of the operation shaft 13 and the position of the attachment body 53.

(How to attach attachment 50)
Next, a method for mounting the attachment 50 in the machine tool 1 will be described.

  First, as shown in FIGS. 1 and 5, the main shaft 2 and the ram 3 are moved to the position of the cradle on which the attachment 50 is placed. Then, the spindle 2 and the ram 3 are lowered, and the adapter 51 of the attachment 50 is inserted into the space 2c1 of the tool mounting portion 2c of the spindle 2, and the spindle end key 2c4 is inserted into the key hole 51a of the adapter 51. At this time, the attachment main body 53 and the lower end surface of the ram 3 are in a separated state. Then, the operating shaft 13 (the first draw bar 16 and the second draw bar 17) is pushed down by a downward pressing force generated in the hydraulic cylinder 19 against the urging force of the leaf spring 18a. Thereby, the collet 12 attached to the lower end portion 16a of the first draw bar 16 is pushed down from the central through hole 2a to the tool mounting portion 2c, and the claw portion 12c of the collet 12 goes out to the collet opening / closing portion 2c3. At this time, the tongue 12b of the collet 12 is moved away from the central axis C by the biasing force of the spring 12d, so that the claw 12c is opened outward.

  At this time, the protrusion 22 of the detected body 21 connected to the upper end of the first draw bar 16 is located at the lowest position I, and the position I of the protrusion 22 at this time is the operation axis position. It is detected by the detection sensor 20.

  Next, as shown in FIGS. 1 and 6, the downward pressing force of the hydraulic cylinder 19 is unloaded. At this time, the operating shaft 13 (the first draw bar 16 and the second draw bar 17) is raised by the restoring force of the leaf spring 18a. Thereby, the collet 12 attached to the first draw bar 16 is pulled back from the tool mounting portion 2c to the central through hole 2a. At this time, each tongue piece 12b is pushed by the inner wall of the central through hole 2a of the main shaft 2, and the claw portion 12c moves in a direction approaching the central axis C while resisting the biasing force of the spring 12d. Thereby, the collet 12 can hold the pull stud 52 of the adapter 51 of the attachment 50.

  Next, after the collet 12 holds the pull stud 52, the ram 3 and the main shaft 2 are raised by about 5 mm so that the attachment main body 53 can be indexed and turned. If the holding of the pull stud 52 is normal, the attachment 50 is raised by about 5 mm as described above. The protruding portion 22 of the detected body 21 in this state is located at the uppermost position II in the state where the pull stud 52 is held, and this position II is detected by the operation shaft position detection sensor 20. Based on this position detection signal, the holding state determination unit 32 of the control unit 31 determines that the holding state is normal.

  In addition, after the collet 12 holds the pull stud 52, the ram 3 and the main shaft 2 are raised so that the attachment main body 53 can be indexed and swiveled so that the attachment main body 53 can be raised in the same amount as the ram 3 and the main shaft 2. It is also possible to check whether the collet 12 holds the pull stud 52 normally by using another method. In this case, the amount of ascent of the attachment main body 53 is confirmed by a position sensor (not shown) provided on the cradle.

  When it is determined that the holding state of the pull stud 52 is normal, the control unit 31 starts a program for the attachment clamping operation. Specifically, as shown in FIG. 7, the attachment holding portion 25 is raised by the hydraulic cylinder 26 of the attachment clamp mechanism 5. At this time, the protruding portion 25b2 of the distal end portion 25b of the attachment holding portion 25 is pressed in a direction approaching the central axis C by the guide surface 27a. Thereby, the attachment holding part 25 is guided upward while maintaining the position where it can be engaged with the step part 55 of the attachment main body 53 in a state where the intermediate part of the attachment holding part 25 is moved in the direction approaching the central axis C. The The attachment main body 53 engaged with the attachment holding portion 25 is lifted together with the attachment holding portion 25, and the carb 3 gear 61 on the ram 3 side and the carbide gear 54 on the attachment main body 53 side mesh with each other. At the same time, the attachment pin 56 provided on the upper end surface of the attachment main body 53 pushes up the probe 28a of the attachment position sensor 28, so that the attachment position sensor 28 detects the position of the attachment 50 based on the amount of movement of the probe 28a.

  The attachment abnormality determination unit 33 of the control unit 31 attaches the attachment 50 based on the position of the first draw bar 16 detected by the operation axis position detection sensor 20 and the position of the attachment 50 detected by the attachment position sensor 28. It is determined whether or not it is normally performed. In the above case, it is determined that the attachment 50 is normally attached.

(Method for determining holding state of pull stud 52)
Next, a method for determining the holding state of the pull stud 52 in the machine tool 1 will be described.

  When the pull stud 52 is normally held by the above procedure, the operating shaft (the first draw bar 16 and the second draw bar 17) are lowered and the collet in the state before the holding, as shown in FIG. Since 12 is in an open state, the protrusion 22 of the detected object 21 connected to the upper end of the first draw bar 16 is at the lowest position I. The position I of the protrusion 22 at this time is detected by the operation shaft position detection sensor 20.

  Further, in the state in which the index 50 of the attachment 50 after holding the pull stud 52 can be turned, as shown in FIG. 6, the collet 12 normally holds the pull stud 52. One draw bar 16 and the second draw bar 17) can be raised to their normal positions. Therefore, the protruding portion 22 of the detected object 21 is located at the uppermost position II. This position II is detected by the operation axis position detection sensor 20. Based on this position detection signal, the holding state determination unit 32 of the control unit 31 determines that the holding state is normal.

  On the other hand, for various reasons, the normal pull stud 52 is not held as shown in FIGS. 5 to 6 and the pull stud 52 is not normally held as shown in FIG. It may become.

  For example, when the main shaft end key 2c4 is not normally inserted into the key hole 51a of the adapter 51 (specifically, friction occurs between the main shaft end key 2c4 and the inner wall of the key hole 51a (a predetermined amount (2. When the adapter is pushed down or when the spindle end key 2c4 is not inserted into the key hole 51a at all, the spindle end key 2c4 pushes down the adapter 51), the adapter 51 is moved by the spindle end key 2c4. Since it is pushed down by a predetermined amount (about 2.5 mm) or more, the adapter 51 is shifted downward from the normal position shown in FIG.

  Therefore, as shown in FIG. 8, the claw portion 12c of the collet 12 does not reach the shaft portion 52a of the pull stud 52, and the head 52b of the pull stud 52 is gripped (so-called half-gripped state). In this case, the collet 12 is open in a direction away from the central axis C as compared to the case where the shaft portion 52a is normally gripped. For this reason, the claw part 12c of the collet 12 cannot be pulled back into the central through hole 2a, and the first draw bar 16 cannot return to the normal position as shown in FIG. . Correspondingly, the protruding portion 22 of the detected object 21 is located at a position III lower than the maximum upper limit position II. The position III of the protrusion 22 is detected by the operation axis position detection sensor 20. Based on this position detection signal, the holding state determination unit 32 of the control unit 31 determines that the holding state is abnormal. As a result, the control unit 31 stops the subsequent attachment mounting operation (for example, the clamping operation of the attachment main body 53 by the attachment clamp mechanism 5), and notifies the operator of an abnormality in the holding state by displaying on the buzzer or the operation panel. It is possible to inform.

  As in the case where the spindle end key 2c4 is not normally inserted into the key hole 51a of the adapter 51, foreign matter such as a facet is inserted between the adapter 51 and the tapered surfaces of the space 2c1 on the spindle 2 side. Also in this case, since the adapter 51 is pushed down by the foreign matter, the adapter 51 is shifted downward from the normal position shown in FIG. Therefore, as shown in FIG. 8, the claw portion 12 c of the collet 12 does not reach the shaft portion 52 a of the pull stud 52, resulting in a semi-gripping state of gripping the head 52 b of the pull stud 52. Also in this case, based on the position detection signal detected by the operation axis position detection sensor 20, the holding state determination unit 32 of the control unit 31 can determine that the holding state is abnormal.

(Attachment abnormality determination method of attachment)
Further, in the machine tool 1 described above, the attachment abnormality determination unit 33 of the control unit 31 is based on the position of the first draw bar 16 and the position of the attachment body 53 detected by the draw bar position detection mechanism 6 and the attachment position detection mechanism 7. The attachment abnormality of the attachment 50 when the attachment main body 53 is held in the ram 3 can be determined.

  For example, in a state before the attachment main body 53 is fixed to the ram 3 (see FIG. 5), when the clutch pin 51c of the adapter 51 is not normally inserted into the insertion hole 57 of the attachment main body 53, the adapter 51 Will sink into the attachment body 53 by the length of the clutch pin 51c. In this state, as shown in FIG. 6, if the pull stud 52 is held by the collet 12, the attachment main body 53 is connected to the clutch even though the adapter 51 is normally held by the tool mounting portion 2 c of the main shaft 2. The abnormal position rises relative to the adapter 51 by the length of the pin 51c.

  In such a case, in the machine tool 1 described above, the attachment position sensor 28 of the attachment position detection mechanism 7 can detect the abnormal position of the attachment main body 53 based on the amount by which the attachment pin 56 is raised. At this time, the attachment abnormality determination unit 33 indicates that the attachment 50 is abnormally attached based on the detection result of the position of the operation shaft 13 (specifically, the position of the first draw bar 16) and the position of the attachment main body 53. Is determined. Specifically, the attachment abnormality determination unit 33 determines that the “an abnormal state where the attachment main body 53 is raised despite the fact that the collet 12 normally holds the pull stud 52”, that is, the insertion of the clutch pin 51c. It is possible to detect an abnormal state. By displaying the detection result on the operation panel of the machine tool 1 or the like, it is possible to inform the operator of the cause of the attachment abnormality of the attachment 50 in more detail.

  As another example, when the collet 12 normally holds the pull stud 52 and the attachment main body 53 is clamped and lifted by the attachment clamp mechanism 5, the carbic gear 61 on the ram 3 side and the attachment main body are raised. If the 53 side carbic gear 54 does not mesh properly, the attachment body 53 may not reach the normal ascent. In this case as well, the attachment position sensor 28 can detect an abnormal position of the attachment main body 53 based on the rising amount of the attachment pin 56. At this time, the attachment abnormality determination unit 33 determines that the attachment 50 is abnormally attached based on the detection result of the position of the operation shaft 13 (specifically, the position of the first draw bar 16) and the position of the attachment body 53. More specifically, “an abnormal state in which the attachment body 53 does not rise normally even though the collet 12 holds the pull stud 52 normally”, that is, the engagement of the carbic gear is abnormal. Can be detected.

  As yet another example, the attachment clamp mechanism 5 may normally clamp the attachment body 53 even though the collet 12 does not hold the pull stud 52 at all. In this case, since the collet 12 does not hold the pull stud 52, the operation shaft 13 (specifically, the first draw bar 16) moves to a position above the position II in the normal holding state. The operation shaft position detection sensor 20 can detect an abnormal position of the first draw bar 16 based on the amount of rise of the detected object 21 connected to the first draw bar 16. On the other hand, when the attachment position sensor 28 detects the normal clamping position of the attachment main body 53, it is possible to determine that the attachment main body 53 is in a normally clamped state. At this time, the attachment abnormality determination unit 33 indicates that the attachment 50 is abnormally attached based on the detection result of the position of the operation shaft 13 (specifically, the position of the first draw bar 16) and the position of the attachment main body 53. More specifically, it is possible to detect that “the attachment body 53 is clamped even though the collet 12 does not hold the pull stud 52”.

(Feature)
(1)
In the machine tool 1 of the present embodiment, instead of detecting the position of the operation shaft 13 such as a draw bar at the rear end surface of the operation shaft 13, the peripheral wall side through hole 2 d is formed in the peripheral wall 2 b of the main shaft 2. By performing position detection at a portion exposed to the outside through the peripheral wall side through hole 2d, it is possible to detect the position of the operation shaft 13 at a position closer to the collet 12.

  That is, the detected object 21 detected by the operation shaft position detection sensor 20 is connected to a portion exposed to the outside through the peripheral wall side through hole 2d in the operation shaft 13, and the operation shaft position detection sensor 20 is detected from the outside of the peripheral wall 2b. The position of the detection body 21 can be detected.

  Moreover, the peripheral wall side through hole 2d that opens in the radial direction of the main shaft 2 has an opening width W that is larger than the amount by which the operation shaft 13 moves between the holding state and the holding release state of the collet 12. Therefore, the operating shaft 13 and the detected body 21 can move in the axial direction of the main shaft 2 without the bolt 21b connecting the operating shaft 13 and the main body 21a of the detected body 21 interfering with the main shaft 2. Is possible. With such a configuration, it becomes possible to dispose the detected object 21 outside the peripheral wall 2b of the main shaft 2 that could not be disposed in the prior art, and thereby disposed closer to the collet 12 than the rear end face of the operation shaft 13. It becomes possible to do. Therefore, it is possible to accurately detect the amount of displacement of the operation shaft 13 without being affected by the increase in the length of the main shaft 2, and as a result, it is possible to accurately determine the holding state of the pull stud 52 by the collet 12. This makes it possible to improve the reliability of holding state determination.

(2)
In addition, the machine tool 1 of the present embodiment can accurately detect the position of the detected object 21 using a magnetic field while suppressing the influence from the main shaft 2.

  That is, in this embodiment, the operation axis position detection sensor 20 detects the position of the detected object 21 by detecting the impedance caused by the eddy current generated inside the main body 21a of the detected object 21 that has received a magnetic field. A sensor is employed, and the main body 21a has a protruding portion 22 that protrudes outward from the peripheral wall 2b. As a result, the distance between the operation axis position detection sensor 20 and the protruding portion 22 of the detected body 21 can be reduced, and the eddy current generated in the detected body 21 while suppressing the influence of impedance caused by the eddy current generated in the peripheral wall 2b. Therefore, it is possible to accurately detect the impedance due to the above, and it is possible to more accurately detect the displacement amount of the operation shaft 13.

(3)
In the machine tool 1 of the present embodiment, the operating shaft 13 includes a first draw bar 16 and a second draw bar 17, and these shaft members 16, 17 are in the central through hole of the main shaft 2 in a state in which the respective end portions are butted together. 2a are arranged side by side. The retreat drive unit 18 of the operation shaft drive unit retreats the first draw bar 16 in the direction away from the tool mounting unit 2c by the restoring force of the leaf spring 18a, whereby the second draw bar 17 is pushed by the first draw bar 16 and retreats. Therefore, the first draw bar 16 and the second draw bar 17 can be moved backward together. Further, when the hydraulic cylinder 19 which is the forward drive portion of the operation shaft drive portion advances the second draw bar 17 in a direction to approach the tool mounting portion 2c, the first draw bar 16 is pushed forward by the second draw bar 17 and moves forward. The first draw bar 16 and the second draw bar 17 can move forward together. In such a configuration, the detected object 21 is a shaft member closer to the collet 12 and is connected to the first draw bar 16 connected to the collet 12, so that the operation shaft 13 abuts the plurality of shaft members. Even if the length is increased, the displacement of the first draw bar 16 to which the collet 12 is connected can be accurately detected without being affected by the length increase. As a result, the holding state of the collet 12 can be determined more accurately.

(4)
In the machine tool 1 of the present embodiment, the operation shaft position detection sensor 20 detects the movement amount of the operation shaft 13, and based on this, the holding state determination unit 32 of the control unit 31 determines the holding state more accurately. It becomes possible. For example, when the collet 12 is correctly holding the pull stud 52, as shown in FIG. 6, the first draw bar 16 of the operating shaft 13 is at a predetermined position corresponding to the normal holding state, and the corresponding cover is provided. The position II of the protrusion 22 of the detection body 21 is detected by the operation axis position detection sensor 20. On the other hand, as shown in FIG. 8, when the collet 12 is in a half-gripping state where the pull stud 52 is not correctly held, the first draw bar 16 stops at an abnormal position different from a predetermined position, and the corresponding covering is applied. The position III of the protrusion 22 of the detection body 21 is detected by the operation shaft position detection sensor 20.

(5)
In the machine tool 1 of the present embodiment, when the adapter 51 of the attachment 50 is connected to the main shaft 2, the attachment main body 53 is held by the ram 3 that houses the main shaft 2 in the machine tool 1 by the attachment holding portion 25. Here, when the pull stud 52 of the adapter 51 of the attachment 50 is not normally held by the collet 12 even if the position of the attachment main body 53 with respect to the ram 3 is in a normal position, for example, when the gripper 12 is in a half-gripping state. There is. On the contrary, even if the pull stud 52 of the adapter 51 of the attachment 50 is normally held by the collet 12, the position of the attachment main body 53 with respect to the ram 3 may not be a normal position. In these cases, there is a possibility that an abnormality in attachment of the attachment 50, for example, a problem such as dropping of the attachment 50 during indexing turning may occur. However, in the above-described embodiment, the controller 31 attachment abnormality determination unit 33 can determine the attachment abnormality of the attachment 50 when the attachment 50 is attached based on the position of the operation shaft 13 and the position of the attachment 50. . Thus, for example, before the attachment 50 is indexed, the abnormality of the holding state of the pull stud 52 by the collet 12 can be determined in advance even if the position of the attachment main body 53 with respect to the ram 3 is in the normal position. It becomes possible, and it is possible to reduce the possibility of the attachment 50 falling during the indexing turn.

(6)
In the machine tool 1 according to the present embodiment, the contact surface 21a1 of the main body 21a of the detected body 21 contacts the outer peripheral surface of the peripheral wall 2b of the main shaft 2 so that the detected body 21 functions to support the operation shaft 13. It becomes possible. Thereby, it is possible to prevent problems such as the operation shaft 13 being displaced from the axis of the main shaft 2.

(7)
In the machine tool 1 of the present embodiment, the detected object 21 has a disk shape that is symmetrical with respect to the central axis C of the main shaft 2, so that the rotational balance of the operation shaft 13 (particularly, the first draw bar 16) is reduced. It is possible to suppress.

(Modification)
(A)
In the above embodiment, an example in which the attachment 50 is mounted on the main shaft 2 and the ram 3 is shown, but the present invention is not limited to this, and a tool holder may be mounted on the main shaft 2 and used. Good. Also in this case, it becomes possible to accurately determine the holding state of the held portion (for example, pull stud) of the tool holder by the collet 12, and the reliability of determination of the holding state is improved.

(B)
In the above embodiment, the main shaft 2 and the ram 3 are arranged extending in the vertical direction, but the present invention is not limited to this, and the main shaft 2 and the ram 3 may be arranged in the horizontal direction. .

(C)
In the above-described embodiment, the main body 21a of the detected object 21 is disposed outside the peripheral wall 2b of the main shaft 2 and is connected to the first draw bar 16 via the bolt 21b penetrating the peripheral wall side through hole 2d. However, the present invention is not limited to this, and it is only necessary that the detected object 21 is connected to a portion of the operation shaft 13 (for example, the first draw bar 16) exposed to the outside through the peripheral wall side through hole 2d. Therefore, as a modified example of the present invention, the detected object is arranged inside the peripheral wall 2b of the main shaft 2 and connected to a portion exposed to the outside through the peripheral wall side through hole 2d in the first draw bar 16. There may be. In this case, if a sensor (such as an infrared sensor) that optically detects the position is used as the operation axis position detection sensor, the position of the detection object disposed inside the peripheral wall 2b is optically transmitted through the peripheral wall side through hole 2d. Can be detected automatically.

  Also in such a modification, the peripheral wall side through hole 2d that opens in the radial direction of the main shaft 2 has an opening width that is larger than the amount by which the operation shaft 13 moves between the holding state and the holding release state of the collet 12. Since W is provided, the operation shaft 13 and the detected object can move in the axial direction of the main shaft 2 without the detected object interfering with the main shaft 2.

DESCRIPTION OF SYMBOLS 1 Machine tool 2 Main axis | shaft 2a Center through-hole 2b Perimeter wall 2c Tool mounting part 2d Perimeter wall side through-hole 3 Ram (storage member)
4 Spindle clamp mechanism 5 Attachment clamp mechanism 6 Drawbar position detection mechanism 7 Attachment position detection mechanism 12 Collet (holding part)
13 Operation shaft 16 First draw bar 17 Second draw bar 20 Operation shaft position detection sensor 21 Detected object 22 Protrusion 28 Attachment position sensor 31 Control unit 32 Holding state determination unit 33 Attachment abnormality determination unit 50 Attachment 51 Adapter 52 Pull stud (cover Holding part)
53 Attachment body C Center axis W Opening width

Claims (6)

A main wall having a peripheral wall surrounding a central through hole extending along the central axis, and a tool mounting portion communicating with the central through hole and having a shape to which a tool holder or an adapter of an attachment can be mounted;
The tool holder or the attachment adapter is held when the tool holder or the attachment adapter is retracted from the tool through part to the tool through part and retracted from the tool through part to the tool through part. A holding portion having a structure in which the holding with the held portion is released when the tool advances from the tool mounting portion,
An operation shaft that is movably arranged along the central axis inside the central through hole, is connected to the holding portion, and performs an operation of causing the holding portion to protrude from the central through hole to the tool mounting portion,
An operation shaft drive unit that moves the operation shaft in a direction in which the central axis extends;
A detected object coupled to the operation shaft;
An operation axis position detection sensor that detects the position of the operation axis by detecting the position of the detected object;
The main shaft has a peripheral wall side through hole that passes through the peripheral wall and communicates the central through hole and the outer peripheral wall;
The detected object is connected to a portion exposed to the outside through the peripheral wall side through hole in the operation shaft,
The peripheral wall side through-hole has the center larger than the amount by which the operation shaft moves between a holding state in which the holding portion holds the held portion and a holding release state in which the holding portion is released. Having an opening width in the direction in which the shaft extends;
The operation shaft position detection sensor is disposed outside the peripheral wall ,
The operation shaft includes a first shaft member and a second shaft member,
The first shaft member and the second shaft member are arranged side by side inside the central through hole of the main shaft in a state where the ends of the first shaft member and the second shaft member are butted together.
The first shaft member is disposed at a position closer to the holding unit than the second shaft member, and is connected to the holding unit,
The detected body is connected to a portion exposed to the outside through the peripheral wall side through hole in the first shaft member,
The operation shaft drive unit includes a retreat drive unit that retreats the first shaft member in a direction away from the tool mounting unit, and a forward drive unit that advances the second shaft member in a direction closer to the tool mounting unit. ing,
A machine tool characterized by that. The operation axis position detection sensor detects a position of the detected object by generating a magnetic field and detecting an impedance due to the eddy current generated by the detected object,
The detected object includes a material capable of generating an eddy current when receiving the magnetic field;
The detected body has a protruding portion that protrudes in a direction away from the peripheral wall outside the peripheral wall of the main shaft.
The machine tool according to claim 1. The operation axis position detection sensor has a configuration capable of detecting a movement amount of the operation axis,
A holding state determination unit that determines a holding state of the held portion by the holding unit based on a movement amount of the operation shaft;
The machine tool according to claim 1 or 2 . A main wall having a peripheral wall surrounding a central through hole extending along the central axis, and a tool mounting portion communicating with the central through hole and having a shape to which a tool holder or an adapter of an attachment can be mounted;
The tool holder or the attachment adapter is held when the tool holder or the attachment adapter is retracted from the tool through part to the tool through part and retracted from the tool through part to the tool through part. A holding portion having a structure in which the holding with the held portion is released when the tool advances from the tool mounting portion,
An operation shaft that is movably arranged along the central axis inside the central through hole, is connected to the holding portion, and performs an operation of causing the holding portion to protrude from the central through hole to the tool mounting portion,
An operation shaft drive unit that moves the operation shaft in a direction in which the central axis extends;
A detected object coupled to the operation shaft;
An operation axis position detection sensor that detects the position of the operation axis by detecting the position of the detected object;
A storage member for storing the main shaft;
An attachment holding section for holding the main body of the attachment in the storage member, and releasing the holding;
An attachment position detection sensor for detecting a position of a main body of the attachment with respect to the storage member;
An abnormality determination unit that determines abnormality of attachment of the attachment when the main body of the attachment is held on the storage member based on the position of the operation shaft and the position of the main body of the attachment;
With
The main shaft has a peripheral wall side through hole that passes through the peripheral wall and communicates the central through hole and the outer peripheral wall;
The detected object is connected to a portion exposed to the outside through the peripheral wall side through hole in the operation shaft,
The peripheral wall side through-hole has the center larger than the amount by which the operation shaft moves between a holding state in which the holding portion holds the held portion and a holding release state in which the holding portion is released. Having an opening width in the direction in which the shaft extends;
The operation shaft position detection sensor is disposed outside the peripheral wall,
A machine tool characterized by that . The object to be detected has a contact surface that contacts an outer peripheral surface of the peripheral wall of the main shaft;
The detected body supports the operation shaft in a state where the contact surface is in contact with an outer peripheral surface of a peripheral wall of the main shaft.
The machine tool according to any one of claims 1 to 4 . The detected object has a symmetrical shape with respect to the axial center of the main axis.
The machine tool according to claim 5 .

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