JP2005271179A - Tool changer of machining tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tool changer of a machining tool, preventing abrasion of the respective parts of a tool holding member to the utmost in attaching and detaching a tool holder. <P>SOLUTION: A holder gripping part 45 is provided on the end of an arm body 41 of a grip arm 36. The holder gripping part 45 includes: a holder receiving part 46 integrally provided on the arm body 41; a pair of gripping arms 48 rotatably supported on the holder receiving part 46; a gripping roller 51 provided on one end of the gripping arm 48; and a compression coiled spring 50 interposed in the other end of the gripping arm 48. The gripping arm 48 is energized in the direction from which the gripping roller 51 comes close by the compression coiled spring 50. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a tool changer for a machine tool for exchanging a tool holder provided on a machine tool and mounted on a spindle with another tool.

  A multi-function machine tool such as a machining center (MC) capable of performing various types of machining on a workpiece in a complex manner with a single device, a spindle head that rotatably supports a spindle holding a tool via a tool holder, The workpiece is processed by reciprocating in the axial direction of the spindle. Such a machine tool is provided with a tool changer that automatically changes a tool holder mounted on the spindle, and a tool that has been processed by the tool changer is replaced with a tool used for the next process.

  The tool changer includes a tool magazine having grip arms as a plurality of tool gripping members that grip a tool holder so as to be swingable and rotationally indexable. When the spindle head is moved from the machining area to the exchange area by the tool changer, the tool holder is transferred between the spindle and the indexed grip arm. Therefore, the grip arm is required to have a configuration that can easily perform insertion and extraction work of the tool holder while ensuring a sufficient gripping force for the tool holder.

  FIG. 6 shows a configuration of a conventional grip arm. As shown in FIG. 6, one of both end portions of the grip arm 1 is a holder gripping portion 2 that is divided into two forks. A hole 3 that penetrates in the opposite direction is provided at the tip of the holder grip 2, and a finger 4 and a biasing spring 5 are accommodated in the hole 3. One end of the urging spring 5 is fixed to a spring retainer 6 attached to the outer surface of the holder grip 2, and the other end is connected to the finger 4. Thus, the finger 4 is urged by the urging spring 5 in a direction protruding from the hole 3 toward the other finger 4. The finger 4 is housed in the hole 3 in a retaining state.

With the above configuration, when the tool holder is arranged in the holder gripping portion 2, the tip end portion of the finger 4 is pressed against and engaged with the gripping groove 7 (shown by a two-dot chain line in FIG. 6) of the tool holder. . Therefore, the tool holder does not fall from within the holder grip 2. At this time, the key groove 7 a of the tool holder is adapted to engage with a positioning key 8 provided at the base of the holder grip 2.
Japanese Patent Publication No. 7-80109

  When the tool holder is attached to the grip arm 1 having the above configuration, the tool holder is inserted between the fingers 4 in the direction indicated by the arrow A. On the other hand, when removing the tool holder from the grip arm 1, the tool holder is pulled out from between the fingers 4 in the direction of the arrow A. In this way, when the tool holder is passed between the fingers 4 in the direction of the arrow A and the direction of the opposite arrow A, the fingers 4 move in the direction of the arrow B while being pressed against the inner surface of the hole 3. In particular, when the tool holder is removed from the holder gripping portion 2, the finger 4 is strongly pressed against the portion indicated by C1, and when the tool holder is attached to the holder gripping portion 2, the finger 4 is pressed strongly against the portion indicated by C2. Is done.

For this reason, one or both of the fingers 4 and the holder gripping portion 2 are worn at the portions indicated by reference numerals C1 and C2, which causes a problem that the life of the grip arm 1 is reduced and the reliability of the tool change operation of the machine tool is reduced. It was.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a tool changer for a machine tool that prevents as much as possible wear on each part of the tool gripping member when the tool holder is attached or detached. is there.

  The present invention includes a spindle for detachably holding a tool holder, and a spindle head that rotatably supports the spindle and moves between a tool change area and a machining area by reciprocating in the axial direction of the spindle. A tool changer provided with a tool gripping member that is provided in a machine tool provided and delivers the tool holder to and from the spindle when the spindle head is located in the tool change area, the tool gripping member being A gripping member main body, and a holder gripping portion that is provided at an end of the gripping member main body and grips the tool holder, and the holder gripping portion is supported by the gripping member main body and is an axis of the main shaft A pair of arm members pivotable about a pivot shaft extending in the direction, a pair of roller members provided at the distal ends of the pair of arm members and engaged with a gripping groove of the tool holder, the pair of arms A spring member that spans between the pair of arm members and urges the pair of arm members in a direction in which the roller member approaches, so that the tool holder is sandwiched between the gripping member main body and the arm member It is characterized by comprising.

  When the tool holder is inserted into the holder holding portion of the tool holding member, the arm member is pushed and spread against the biasing force of the spring member. At this time, the roller member rotates along the gripping groove with the insertion of the tool holder into the holder gripping portion while engaging with the gripping groove of the tool holder. And a tool holder is clamped by a holding member main body and an arm member by being completely inserted in a holder holding part.

  According to the tool changer for a machine tool of the present invention, wear does not occur in each part of the tool gripping member when the tool holder is inserted into or removed from the holder gripping part.

  The first embodiment of the present invention will be described below with reference to FIGS. First, the configuration of the machine tool according to the present embodiment will be described. As shown in FIG. 1, a machine tool 11 includes a table 14 that holds a workpiece (not shown), a machine tool body 15, a tool such as a drill or a tap inside a splash guard 12 for preventing scattering of cutting waste. A tool exchanging device 17 for exchanging 16 is arranged.

The splash guard 12 includes a display unit 18 for displaying the operation status of the machine tool 11, buttons for inputting a command to the machine tool 11 and inputting conditions, a floppy (registered trademark) disk drive, and the like. An operation panel 19 provided with a workpiece, a workpiece changing port 20 for entering and leaving the workpiece and maintenance, an inspection hatch 21 and the like are provided.
As shown in FIG. 2, the machine tool main body 15 includes a Z-axis servo motor (hereinafter referred to as a Z-axis motor) 23 fixed to a column 22 and a ball screw 24 by the Z-axis motor 23 (corresponding to a drive mechanism). Is configured around a spindle support 25 that moves up and down in the column 22 and a magazine support 27 that is fixed to the column 22 via a frame 26.

The spindle head 25 includes a spindle 28 having a tool holding portion (not shown), a spindle motor 29 that rotationally drives the spindle 28, a pair of first cam bodies 30, a second cam body 31, and the tool holding section. A clamp / unclamp mechanism (not shown) for detachably holding the tool holder 32 held by the tool holder 32 is provided. The tool 16 is fitted to the lower end of the tool holder 32.
The tool changer 17 includes a tool magazine 33, a magazine motor 34, and the like. The tool magazine 33 is supported by the magazine support 27 and rotates about an axis a that is inclined obliquely to the lower left, and a plurality of, for example, ten grip arms provided radially on the outer periphery of the magazine base 35. 36 (corresponding to a tool gripping member). Ten clevises 37 are provided on the outer periphery of the magazine base 35 at a predetermined angle, and the grip arm 36 is swingably supported by the clevis 37 via a swinging shaft 36a.

  A magazine cover 38 (shown only in FIG. 1) is fixed to the side surface of each grip arm 36 opposite to the surface facing the spindle head 25. The magazine cover 38 is bent along the grip arm 36 and has a larger area than the grip arm 36. When the spindle head 25 is located in the tool change area and the magazine base 35 is in a state where the rotation can be indexed, the magazine cover 38 has a truncated cone shape as a whole so that the tool magazine 33 is covered by the magazine cover 38. It has become.

  The magazine base 35 is rotated by the magazine motor 34. A magazine cam 34 is connected to a bevel cam (both not shown) via a rotating shaft and a bevel gear. The magazine base 35 has ten roller-shaped cam followers (not shown) provided corresponding to the positions where the grip arms 36 are disposed. The cam follower is sequentially fitted in the cam groove of the Babel cam, so that intermittent indexing rotation is applied to the magazine base 35.

The first cam body 30 is fixed to the bottom surface of the spindle head 25. The cam body 31 is provided on a surface that is a vertical surface of the spindle head 25 and faces the tool magazine 33 via a compression coil spring (not shown). The cam bodies 30 and 31 have cam surfaces 30a and 31a, respectively. On the other hand, the grip arm 36 has first and second cam followers 39 and 40. Each of the first cam followers 39 is provided on the outer surface of the tip end portion of the tool gripping portion 28 (see FIG. 3). It abuts on the surface 20a. The second cam follower 40 is provided in the vicinity of the swing shaft 36 a of the grip arm 36, and abuts on the cam surface 31 a of the cam body 31 within a predetermined lift region of the spindle head 25.
With the above configuration, the grip arm 36 is pivoted by the cooperative action of the first and second cam bodies 30, 31 and the first and second cam followers 39, 40 as the spindle head 25 moves up and down. A predetermined oscillating motion in the direction indicated by the arrow D is performed around the center.

Next, the configuration of the grip arm 36 will be described with reference to FIGS. 3 and 4.
The arm main body 41 (corresponding to the gripping member main body) of the grip arm 36 has a hole (not shown) at the end on the magazine base 35 side (inner peripheral side) of both ends thereof. A steel ball 42 is accommodated together with a compression coil spring (not shown). A part of the steel ball 42 protrudes from the end face of the arm main body 41 and abuts on a guide face 43 provided around the axis a of the magazine base 35.

The swing shaft 36 a is provided closer to the magazine base 35 than the central portion in the longitudinal direction of the arm body 41.
A portion of the arm main body 41 on the side opposite to the magazine base 35 (outer peripheral side) than the swing shaft 36a is bent near the center in the longitudinal direction, and a portion ahead of the bent portion 44 is gripped by the holder. Part 45. Specifically, a holder receiving portion 46 having a bifurcated shape is provided in a portion of the arm main body 41 that is ahead of the bent portion 44. An arcuate holder support surface 47 is provided on the inner surface of the holder receiving portion 46. The holder support surface 47 is set to a shape and size capable of supporting the tool holder 32.

  In addition, a pair of gripping arms 48 (corresponding to arm members) are supported on the base of the holder receiving portion 46 via a rotation shaft 49. The grip arm 48 is disposed on the surface of the holder receiving portion 46 on the side opposite to the main spindle head 25, and is configured so that the vicinity of the center in the longitudinal direction is the center of rotation. The end of the grip arm 48 on the magazine base 35 side is located near the bent portion 44, and a compression coil spring 50 is interposed therebetween.

  An end of the gripping arm 48 on the side opposite to the magazine base 35 protrudes from the tip of the holder receiving portion 48, and a gripping roller 51 (corresponding to a roller member) is rotatably supported by the protruding portion. The rotating shaft 51 a of the gripping roller 51 is set to be substantially parallel to the axis of the tool holder 32 gripped by the holder gripping part 45. The center of the gripping roller 51 in the thickness direction is set to substantially coincide with the center of the holder receiving portion 46 in the thickness direction. The gripping arms 48 are biased in the direction approaching the roller 51 by the compression coil spring 50.

The roller 51 is set to a size that can be engaged with a gripping groove 32 a provided around the outer periphery of the tool holder 32. In particular, in this embodiment, the cross-sectional shape of the outer peripheral surface of the roller 51 is configured as a trapezoidal shape corresponding to the shape of the gripping groove 32a. The size and spring constant of the compression coil spring 50 are set so that the roller 51 engaged with the grip groove 32a of the tool holder 32 can be pressed strongly against the grip groove 32a. With such a configuration, the tool holder 32 attached to the holder gripping portion 45 is securely gripped by the holder support surface 47, the gripping arm 48, and the gripping roller 51.
A positioning key 52 protruding from the holder support surface 47 is fixed at the center of the base of the holder receiving portion 46. The grip groove 32a of the tool holder 32 is provided with a key groove (not shown) corresponding to the positioning key 52, and the tool holder 32 is positioned by the positioning key 52 and the key groove.

  In the machine tool, a tool change operation is executed as follows in accordance with a preset machining program. The machining program is for instructing the tool exchange timing, the tool 16 used for the next machining, the motor driving amount for the tool exchange (the rotation angle of the magazine base 35), and the like, and executes a series of machining operations. At this time, the operator inputs a key. In the state before the tool change operation is started, the cam followers 39 and 40 are in contact with the cam surfaces 30a and 31a, respectively, and the holder grip 45 of the grip arm 36 is at a position away from the main shaft 28.

  When the execution of the tool change operation is started, the spindle head 25 located below the origin for machining the workpiece is moved to an exchange position that is raised by a predetermined distance from the origin. Then, the grip arm 36 is swung by the cam action of the cam surfaces 30a, 31a and the cam followers 39, 40, and the holder grip 45 of the grip arm 36 is moved from a separated position away from the main shaft 28 to a close position close to the main shaft 28. Moving. As a result, the tool holder 32 mounted on the main shaft 28 is inserted into the holder receiving portion 46 while the gripping roller 51 of the grip arm 36 is engaged with the gripping groove 32a. As a result, the tool holder 32 is held between the holder support surface 47 and the grip arm 48 in a state where the grip roller 51 is engaged with the grip groove 32a.

  Next, extraction of the tool holder 32 held by the tool holding portion of the main shaft 28 is started. First, the clamping / unclamping mechanism ends the unclamping operation on the tool holder 32 immediately before the spindle head 25 reaches the replacement position. When the spindle head 25 is further raised, the tool holder 32 held by the spindle 28 is left in the holder grip 45 of the grip arm 36, and the tool holder 32 is transferred from the spindle 28 to the grip arm 36. Complete.

  In this state, when the magazine motor 34 is driven and the rotation of the magazine base 35 is indexed, another grip arm 36 holding the tool 16 to be used next moves directly below the spindle 28 of the spindle head 25. When the spindle head 25 is lowered, the tool holder 32 held by the newly determined grip arm 36 is inserted into the tool holding portion of the spindle 28. On the other hand, as the spindle head 25 descends, the cam followers 39 and 40 of the grip arm 36 again come into contact with the corresponding cam surfaces 30a and 31a. As a result, the grip arm 36 starts to swing around the swing shaft 36a. At the same time, clamping of the tool holder 32 inserted into the tool holding portion of the spindle 28 by the crank / unclamp mechanism of the spindle head 25 is started. When the spindle head 25 is further lowered, the tool holder 32 is completely clamped by the tool holder of the spindle 28, and the grip arm 36 is completely detached from the tool holder 32 clamped by the tool holder.

  Thus, in this embodiment, the arm main body 41 is provided with a pair of gripping arms 48 so as to be rotatable, and a gripping roller 51 that engages the gripping groove 32 a of the tool holder 32 is provided at the tip of the gripping arm 48. . When the tool holder 32 is inserted into the holder gripping part 45 or when the tool holder 32 is removed from the holder gripping part 45, the gripping arm 48 is pushed and spread against the biasing force of the spring 50. The tool holder 32 passes between the rollers 51 by separating the rollers 51. Therefore, unlike the conventional tool changer, since the members such as the gripping roller 51 and the gripping arm 48 are not strongly pressed against a specific part when the tool holder 32 is attached or detached, the holder gripping portion 45 is worn. Can be suppressed.

When the tool holder 32 passes between the gripping rollers 51, the roller 51 rotates while engaging with the gripping grooves 32a. Therefore, unlike the conventional tool changer in which the fingers repair the grip groove as the tool holder passes, wear of the grip roller 51 itself can be suppressed.
Further, in this embodiment, the gripping arms 48 are connected by a spring 50, and the urging force of the gripping roller 51 is obtained by the spring 50. Therefore, as compared with the conventional tool changer in which the biasing spring is built in the grip arm, the installation space of the spring 50 is not limited, and the degree of freedom in designing the spring 50 is increased. For this reason, by setting the size of the spring 50 and the spring constant to an appropriate value, it is possible to realize a configuration of the grip arm 26 having excellent tool exchange operability while ensuring a sufficient gripping force of the tool holder 32.
Further, since the spring 50 is provided so as to cross the grip arm 26, even if the spring 50 is enlarged in order to secure a sufficient gripping force of the tool holder 32 by the gripping arm 48, the grip arm 26. Does not become large.

  FIG. 5 shows a second embodiment of the present invention, and the differences from the first embodiment will be described. In other words, in the second embodiment, the outer peripheral surface of the gripping roller 51 is formed in a circular arc shape. According to such a configuration, when the gripping roller 51 is engaged with the gripping groove 32a of the tool holder 32, the contact area between the gripping roller 51 and the gripping groove 32a is reduced. For this reason, the wear of the gripping roller 51 can be further suppressed.

The present invention is not limited to the above-described embodiments, and for example, the following modifications are possible.
Instead of swinging each grip arm, the entire magazine base may swing integrally so that each grip arm is displaced between the proximity position and the separation position.

A spring member (pulling coil spring) may be attached to the gripping roller side with respect to the rotation center of the grip arm.
The grip arm may be configured to be swung by a mechanism other than the cam mechanism.

The perspective view which shows the 1st Example of this invention and shows the whole structure of a machine tool Partial vertical side view of the periphery of the spindle head and tool changer Top view of grip arm Enlarged side view of the periphery of the holder gripping part of the grip arm shown with the tool holder attached FIG. 4 equivalent view showing a second embodiment of the present invention. Plan view showing conventional configuration of grip arm

Explanation of symbols

In the drawings, 11 is a machine tool, 15 is a machine tool body, 17 is a tool changer, 23 is a Z-axis motor (drive mechanism), 25 is a spindle head, 28 is a spindle, 30 and 31 are cam bodies, and 32 is a tool holder. , 33 is a tool magazine, 36 is a grip arm (tool gripping member), 39 and 40 are cam followers, 41 is an arm main body (gripping member main body), 45 is a holder gripping part, 48 is a gripping arm (arm member), and 50 is compression Coil springs (spring members) 51 are gripping rollers (roller members).

Claims (3)

A machine tool comprising: a spindle that detachably holds a tool holder; and a spindle head that rotatably supports the spindle and moves between a tool change area and a machining area by reciprocating in the axial direction of the spindle. A tool changer provided with a tool gripping member for transferring the tool holder to and from the spindle when the spindle head is located in the tool change area;
The tool gripping member includes a gripping member main body and a holder gripping portion that is provided at an end of the gripping member main body and grips the tool holder.
The holder gripping portion is supported by the gripping member body and is pivotable about a pivot shaft that extends in the axial direction of the main shaft, and the tool holder provided at the tip of the pair of arm members A pair of roller members that engage with the gripping grooves of each other, and a spring member that is spanned between the pair of arm members and biases the pair of arm members in the direction in which the roller members approach, A tool changer for a machine tool, wherein the tool holder is sandwiched between the arm member and the arm member. A tool magazine which is provided so as to be indexable and rotates, and a plurality of the tool gripping members are radially arranged on the outer periphery thereof;
A drive mechanism for reciprocating the spindle head in the axial direction of the spindle;
A cam body provided on the spindle head and a cam mechanism provided on the tool gripping member and comprising a cam follower that contacts the cam body based on the reciprocating movement of the spindle head;
When the tool gripping member is indexed, the tool gripping member is swung around a swinging shaft that is substantially orthogonal to the axis of the main shaft by the cam action of the cam mechanism, and closes to the main shaft with a retracted position retracted from the main shaft. 2. The tool changer for a machine tool according to claim 1, wherein the tool changer is configured to be displaceable between adjacent positions. The tool changer for a machine tool according to claim 1 or 2, wherein the roller member has an outer peripheral surface formed in an arcuate shape.

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