JP3545555B2 - Attachment fastening device for machine tools - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an attachment attached to a spindle head end of a machining center.
[0002]
[Prior art]
Conventionally, this type of attachment is generally large and cannot be stored in the tool magazine, and a stand is provided separately from the tool magazine, and when mounted on the spindle head, the spindle head moves to the position of this stand. I was wearing it. At the time of mounting on the spindle head, as shown in FIG. 6, an L-shaped hook 94 at the tip of the piston 93 of the hydraulic cylinder device on the spindle head engages with the jaw 92 of the large diameter coupling 91 provided on the attachment. It is known that the piston 93 is pulled up and clamped by a piston 93.
[0003]
[Problems to be solved by the invention]
The large attachment described in the related art has a problem that the structure is complicated because a hydraulic cylinder is arranged on the spindle head side and hydraulic piping is required, and piping equipment is required and the cost is high. In addition, replacement of the attachment requires a separate table, which requires an installation place, and is subject to restrictions such as interference. If you try to use the automatic tool change arm for this attachment change, the dimensions of the gripping part of the change arm can be changed only for the attachment of the same size as the tool, and the overall dimensions are limited, and the internal components are reduced in size. However, there is a problem that the attachment has a small processing ability.
[0004]
The present invention has been made in view of these problems of the prior art, and aims at attaching a relatively large attachment to a spindle head without using a special device such as a hydraulic piston. Another object of the present invention is to provide an attachment fastening device for a machine tool that can easily and automatically clamp a strong clamp.
[0005]
[Means for Solving the Problems]
The attachment fastening device for a machine tool according to the present invention is an attachment that performs cutting by fitting to a spindle head end of a machine tool such as a machining center that pulls up a tool through a collet with a draw bar inserted through the center of the spindle. An attachment body provided with a mating coupling that engages with the inner peripheral flanged coupling at the lower end surface of the spindle head, and a flange formed with a cut stud at the lower end where a pull stud gripped by a collet is attached and engages with the spindle drive key at the lower end A shank member attached to the main shaft tip tapered hole, wherein a small-diameter shaft having a member which is movable in the axial direction with respect to the attachment main body at the center of the lower end and bears the weight of the attachment main body is provided at the shaft end; Between the attachment body weight receiving member and the attachment body. A first elastic member that urges the attachment body in a pulling-up direction, and is swingable in a plane including a center line of the attachment body provided at a plurality of locations on an inner circumference of a mating coupling on an upper end surface of the attachment body. One end of the arm facing upward has a clamp claw that is removably engaged with the upper surface of the inner peripheral flange of the coupling. The other arm facing the center of the attachment main body has a top surface on the top of the flange of the shank member. An L-shaped clamp arm that abuts the lower surface, and a plurality of forces for urging the clamp claws of each of the L-shaped clamp arms in a direction to always engage with the inner peripheral flange portion are smaller than the first elastic member. And a clamp pawl is engaged with the inner peripheral flange of the coupling together with the engagement of the coupling when the attachment is mounted on the main shaft. It is intended to remove the engagement of the clamp jaws of the L-shaped clamp arm by lowering the shank member by releasing the pulling collet.
[0006]
According to the fastening device for an attachment for a machine tool configured as described above, only by holding and pulling up the pull stud with the collet in the main shaft so as to mount a normal tool, the large diameter of the attachment is obtained by the first elastic member. Is pressed against the large-diameter first coupling at the tip of the spindle head, and the clamp claw automatically engages with the upper surface of the inner peripheral flange portion of the first coupling on the spindle head side, thereby increasing the cutting force. The attachment is clamped to the spindle head with a force that does not move.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 is an external view of a machining center, FIG. 2 is an explanatory view of a tool magazine and a replacement arm of the machining center, FIG. 3 is a cross-sectional view showing a state where an attachment is attached to a spindle head, and FIG. 4 is a part of FIG. 3 showing a clamp arm portion. FIG. 5 is an enlarged view of the enlarged portion, and is a view mainly showing a clamp arm arrangement state when the attachment is not mounted on the spindle head.
[0008]
In the machining center shown in FIG. 1, a table 2 is placed on a bed 1 installed on a floor so as to be movable and positioned in the X-axis (front-back) direction. A column 3 is erected on the floor on both sides of the bed 1, and a top beam 4 is fixed on the column 3. The column 3 has a W-axis (vertical) guide on the front surface, and a cross rail 5 is mounted on the W-axis guide so as to be movable and positionable. The cross rail 5 has a guide in the Y-axis (left / right) direction on the front surface. A spindle head 6 is mounted on the Y-axis guide so as to be movable and positionable. A spindle ram 7 is mounted on the spindle head 6 in the Z-axis (vertical) direction. Is provided so as to be movable and positionable.
[0009]
An attachment 8 is detachably attached to the tip of the spindle ram 7, and a tool magazine device 9 that can store the attachment together with tools is provided at the left end of the left column 3. An exchange arm unit 11 is provided at the lower left portion of the cross rail 5 so as to be pivotable on the tool magazine side and the main spindle side in a horizontal plane, to be able to pivot the arm pivot axis horizontally and vertically, and to be able to move horizontally linearly. The exchange arm unit 11 is a twin-arm type having centrally symmetric tool grippers A1 and A2 and attachment grippers B1 and B2 corresponding to the V-shaped grip grooves of tools having different grip diameters and the V-shaped grip grooves of the attachment. The compound exchanging arm 12 is provided so that it can be turned around the turning center axis 52 by the NC and can be moved and positioned in the turning center axis direction.
[0010]
In FIG. 2, a large attachment 8 having the same shank dimensions as a normal tool is housed in a tool magazine 9 in addition to a normal tool. An exchange arm unit 11 that can rotate and axially move a tool and an attachment 8 between the tool magazine 9 and the spindle head 6 has a pair of center-symmetric tool exchanges used when exchanging normal tools. Gripper B1 used for exchanging and transporting an attachment 8 having a gripping dimension different from that of a normal tool, in addition to the grippers A1 and A2, and an attachment used for rotating and indexing the attachment 8 at the position of the spindle head 6. A composite exchange arm 12 having a total of four grippers formed as a pair with the indexing gripper B2 symmetrically with respect to the center is provided.
[0011]
Although not shown, a gripping tool and an auxiliary finger that opens and closes to prevent the attachment from falling off are provided at the tip of each gripper. The pair of tool replacement grippers A1 and A2 and the attachment replacement gripper B1 are provided with detent pawls 14 for preventing rotation of the tool and the attachment 8, respectively, so that the tools and the attachment 8 do not shift during transport.
However, since it is necessary to rotate the entire attachment in the gripper B2 for indexing the attachment, a claw for preventing rotation is not attached, and the auxiliary finger is not strongly tightened when gripping the attachment.
[0012]
In FIG. 3, a spindle ram 7 is provided in the spindle head 6 so as to be movable in the spindle axis direction, and a large-diameter coupling 21 for fixing the attachment 8 is provided on a lower end surface of the spindle ram 7. The coupling 21 is provided integrally with an inner peripheral flange 21a which engages with a clamp claw described later.
[0013]
A main shaft 22 having a through hole is rotatably supported by a bearing 23 in the main shaft ram 7. The tip of the through hole 22a of the main shaft 22 is formed in a taper capable of receiving a shank portion of the tool. A draw bar 24 that is operated by a fluid pressure cylinder device (not shown) is inserted into the through hole of the main shaft 22 so as to be movable in the axial direction. The pull stud 31 is engageable with the tip of the draw bar 24 and fixed to the tool shank. Is provided.
[0014]
The attachment 8 has a large V-shaped groove 26a for gripping, which is different from the normal V-shaped groove for gripping a normal tool, on the outer periphery of the main body 26, and receives the grippers B1, B2 for attachment. Further, a key groove 27 for engaging with the claw 14 of the attachment replacement gripper B1 is formed in the V-shaped groove 26a. A large-diameter coupling 29 that meshes with a large-diameter coupling 21 provided on the lower surface of the main shaft ram 7 is attached to a surface of the main body 26 of the attachment 8 facing the main shaft ram 7. The attachment 8 has a shank portion 30 that fits into the tapered hole 22 b of the spindle 22 when attached to the spindle head 6, and a pull stud 31 that is gripped by a collet 25 that is engaged with the draw bar 24.
[0015]
On the lower end surface of the flange 32 of the shank portion 30, a small-diameter coupling 33 concentric with the above-described large-diameter coupling 29 is engraved. At the center of the lower end surface of the shank portion 30, a spline shaft 34 having a small end 37 at its tip is protruded, and a female shaft of a sleeve shaft of a bevel gear 36 rotatably supported by a bearing 35 at the center of the attachment body 26. Spline and spline fit. The bevel gear 36, the attachment body 26, the shank 30, and the spline 30 are interposed between the bevel gear 36 and the collar 38 fitted to the tip of the small diameter portion 37 of the spline shaft 34 and fixed by a nut. The shaft 34 is always urged to approach the shaft 34 in a direction of approaching the shaft 34.
[0016]
A small-diameter coupling 40 that engages with a small-diameter coupling 33 engraved on the lower surface of the flange 32 is attached to a surface of the attachment body 26 that faces the end surface of the flange 32. There is a step between the meshing position of the large-diameter couplings 21 and 29 and the meshing position of the small-diameter couplings 33 and 40. When the large-diameter coupling is engaged when the attachment is attached to the main shaft, the small-diameter coupling does not mesh. In the attachment body 26, a tool spindle 42 having a bevel gear 41 meshing with the bevel gear 36 is rotatably supported by a bearing 43 at an angle to the axis of the spindle 22. The angle between the tool spindle 42 and the spindle is a right angle in the present embodiment, but is not limited to this.
[0017]
A drive key 44 is attached to the tip end surface of the main shaft 22 to reliably transmit the rotation of the main shaft 22 to a tool, and can be fitted into a key groove 45 cut out in the flange 32 of the shank portion 30. Then, the pull stud 31 is released from the collet 25, and the shank portion 30 approaches the attachment main body 26 by the disc spring 39, and the small diameter couplings 33 and 40 are engaged with each other. Then, the attachment main body 26 is separated from the main shaft ram 7 to have a large diameter. Even when the couplings 21 and 29 are disengaged and a slight gap is formed between both ends of the couplings 21 and 29, the drive key 44 still maintains the engagement state with the key groove 45 of the flange 32. It is elongated in the direction of the main shaft axis.
[0018]
In FIG. 4 and FIG. 5, a plurality of two pairs in this example are provided at centrally symmetric positions of the lower end surface of the large diameter coupling 29 attached to the upper end surface of the attachment main body 26 and the inner peripheral surface following the lower end surface. The notch portions 29a are cut out, and the clamp claw members 80 are attached to the respective notch portions 29a symmetrically with respect to the center. A bracket 82 of the clamp claw member 80 is fixed to the notch 29a of the large diameter coupling 29 so as to protrude inward by a plurality of bolts 81. An L-shaped clamp arm 83 is attached to the bracket 82 by a pivot pin 84. The attachment body 26 is swingably provided in a plane including the center line.
[0019]
The L-shaped clamp arm 83 has an arm 83a facing upward and an arm 83b facing laterally, that is, the center side of the attachment main body, formed integrally at a substantially right angle, and is fixed to the tip of the ram 7 at the upper end of one arm 83a. A clamp claw 83c that engages with the upper surface of the inner peripheral flange 21a of the large-diameter coupling 21 so as to be able to be freely engaged with and disengaged from the upper end of the other arm 83b. A surface 83e is formed.
[0020]
Further, a blind hole 26b is formed vertically below the tip of the other arm 83b of each L-shaped clamp arm 83 in the attachment body 26 from above, and a top end surface of the blind hole 26b is formed in a spherical surface. The attached pin 86 is vertically movably fitted, and a disc spring 85 whose total thrust at four locations is weaker than the thrust of the disc spring 39 is interposed between the stepped end face of the headed pin 86 and the bottom of the blind hole 26b. The L-shaped clamp arm 83 is urged by a disc spring 85 in a direction in which the clamp claw 83c at the upper end of one arm 83a can engage with the inner peripheral flange 21a.
[0021]
Therefore, when the pull stud 31 is released from the collet 25, the shank portion 30 approaches the attachment body 26 by the disc spring 39, and the small diameter couplings 33 and 40 mesh with each other, the contact surface 83e of the other arm 83b of the L-shaped clamp arm 83 is changed. The arm 83a swings in contact with the lower surface of the flange 32, and the one arm 83a assumes a substantially vertical posture, and the clamp claw 83c comes off the upper surface of the flange 21a.
[0022]
When the pull stud 31 engages with the collet 25 and the shank portion 30 is pulled up to engage the large diameter couplings 21 and 29 with the force of the disc spring 39, the lower surface of the flange 32 separates from the contact surface 83e, and the disc spring 85 The L-shaped clamp arm 83 is swung so that one arm 83a is inclined from the substantially vertical position to the outward position, and the wedge effect acts so as to press the upper surface of the inner peripheral flange 21a by a change in the vertical position of the clamp claw 83c at this time. , And the attachment 8 is strongly clamped to the spindle head 6 assuming that the large-diameter couplings 21 and 29 are firmly engaged with each other.
[0023]
Next, the operation of the embodiment will be described.
When the attachment 8 is accommodated in the tool magazine 9, the shank portion 30 and the attachment main body 26 are approached by the disc spring 39 to keep the small-diameter couplings 33 and 40 engaged, and the arm 83 a of the L-shaped clamp arm 83 is moved. The vertical position substantially parallel to the center line of the attachment body 26 is maintained, and the shank portion 30 cannot rotate with respect to the attachment body 26. Therefore, the tool spindle 42 is not rotated with respect to the attachment main body 26, and the key position of the tool spindle 42 can maintain a fixed positional relationship with the keyway of the flange 32 of the shank 30.
[0024]
When the attachment 8 is taken out from the tool magazine 9 and transported, the V-shaped groove 26a of the attachment body 26 is gripped by the attachment replacement gripper B1 of the composite replacement arm 12 of the replacement arm unit 11, and at this time, the claw 14 of the gripper B1 The engagement with the key groove 27 cut out in the shape groove 26a prevents the attachment 8 from being displaced in the gripper B1. For this reason, the key groove 45 of the flange 32 of the shank portion 30 is conveyed to the main shaft without being displaced, and the key groove 45 of the flange 32 can be correctly engaged with the drive key 44 of the main shaft 22.
[0025]
When the attachment 8 is conveyed to the position of the main shaft, the shank portion 30 is inserted into the tip tapered hole 22b of the main shaft 22, the draw bar 24 is pulled by a disc spring (not shown), and is pulled up to the rear of the main shaft 22, and the pull stud 31 is moved to the collet 25. Is gripped by At this time, the attachment body 26 is also pulled up through the disc spring 39 up to a point in the middle. However, when the large-diameter coupling 29 on the attachment body side engages with the large-diameter coupling 21 provided on the end surface of the spindle ram 7, the attachment body 26 It is fixed and pulling is prevented.
[0026]
When the pull stud 31 is further pulled up in this state, and the shank portion 30 and the flange 32 are both pulled up, the disc spring 39 is compressed by the collar 38 attached to the small diameter portion 37 at the tip of the spline shaft 34. Since the attachment body 26 is fixed by the engagement of the large diameter couplings 21 and 29, the engagement of the small diameter couplings 33 and 40 is released. As a result, the contact surface 83e of the L-shaped clamp arm 83 is released from the lower surface of the flange 32, and one arm 83a facing upward is swung by the force of the disc spring 85 to change from a substantially vertical position to an inclined position, thereby causing the clamp claw to move. 83c is engaged with the upper surface of the inner peripheral flange 21a of the large coupling 21, and the engagement of the large couplings 21 and 29 is strengthened by a wedge effect utilizing a change in the vertical position of the clamp claw 83c at this time. I do.
[0027]
Thereafter, the pulling is completed when the shank portion 30 is pressed against the inner surface of the tapered hole 22b at the tip end of the main shaft 22. At this time, since the disc spring 39 is compressed and deflected, the spring force is transmitted to the contact surfaces of the large-diameter couplings 29 and 21 through the bevel gear 36 and the bearing 35, and the attachment body 26 is strongly pressed to the main shaft ram 7. However, a strong pressing force by the clamp claw 83c is applied to this, and a large clamping force that can withstand strong cutting without obtaining other elements such as a hydraulic mechanism is obtained.
[0028]
Next, a method of indexing the attachment main body 26 will be described. The spindle head 6 and the exchanging arm unit 11 are positioned at the tool exchanging position, the turning servomotor is driven by the command of the NC device to turn the compound exchanging arm 12, and the attachment body is provided by the attachment indexing gripper B2 having no detent key. The V-shaped groove 26a of FIG.
[0029]
The draw bar 24 pulled up by the spring is advanced by a fluid pressure cylinder device (not shown), the grip of the pull stud 31 by the collet 25 is released, and the engagement of the clamp claw 83c is released. At the same time, the insertion / removal servomotor is driven by a command from the NC device, and the composite exchange arm 12 is moved in the main shaft axis direction by the first-stage extraction operation to disengage the large-diameter couplings 21, 29.
[0030]
At this time, the moving distance is set to a distance at which the leading ends of the large diameter couplings 21 and 29 have a slight gap. The shank portion 30 is pulled toward the attachment main body 26 by the disc spring 39, the small diameter couplings 33 and 40 are engaged, and the engagement of the clamp claws 83c is released.
[0031]
However, the drive key 44 attached to the tip of the main shaft 22 still maintains a state of being engaged with the key groove 45 of the flange 32. In this state, if the main shaft 22 is rotated by a servo motor (not shown) at a predetermined angle in accordance with an NC command, the rotation is transmitted to the drive key 44, the flange 32, the small diameter couplings 33 and 40, and the attachment main body 26, and the rotation is transmitted to the inside of the gripper B2. The entire attachment 8 is indexed.
[0032]
After the completion of the indexing, the insertion / removal servomotor is driven to move the composite exchange arm 12 and the gripper B2 toward the spindle head 6 in the first step insertion operation so that the large diameter couplings 21 and 29 are engaged, and the drawbar 24 is moved. When the pull stud 31 is gripped and clamped by the collet 25 by pulling up with the disc spring, the attachment 8 is reattached to the spindle head 6, the small-diameter couplings 33 and 40 are disengaged, and the clamp claw 83c is moved to the inner peripheral flange 21a. And the cutting process can be resumed.
[0033]
As another embodiment of the compound exchange arm 12, if the detent claw 14 of the attachment exchange gripper B1 can be taken in and out of the gripper by a hydraulic piston, an electromagnetic solenoid, a cam, or the like, the attachment exchange gripper B1 can be used to divide the attachment. This makes it possible to use the extension gripper B2 as well.
In addition, a plurality of rollers can be attached to the inner periphery of the attachment indexing gripper B2 of the composite exchange arm 12 in order to smoothly rotate the attachment.
[0034]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
According to the first aspect, since the first elastic member (disc spring) is incorporated in the attachment body to urge the shank portion and the attachment body always in the approaching direction, a tool for attaching the attachment to the spindle head is required. Using the operation of pulling up and clamping, the first body member is flexed to strongly press the attachment body to the main shaft ram by the elasticity of the first body member, and the clamp pawl of the L-shaped clamp arm is connected to the second body. Since the resilient force of the member (disc spring) presses and engages the upper surface of the inner peripheral flange on the spindle head side, the attachment can be automatically operated by one operation without using a large-scale clamping means such as another hydraulic mechanism. Can be strongly clamped to the spindle head.
[Brief description of the drawings]
FIG. 1 is an external view of a machining center.
FIG. 2 is an explanatory diagram of a tool magazine and an exchange arm.
FIG. 3 is a sectional view showing a state in which the attachment of the present invention is attached to a spindle head.
FIG. 4 is a partially enlarged cross-sectional view around a clamp claw in FIG. 3;
FIG. 5 is a top view of the attachment detached from the spindle head, and is a diagram mainly illustrating a state where clamp claws are provided.
FIG. 6 is a sectional view showing a state in which a conventional attachment is attached to a spindle head.
[Explanation of symbols]
6 Spindle head 7 Spindle ram 8 Attachment 12 Replacement arm A1, A2 Tool gripper B1 Attachment gripper B2 Attachment indexing gripper 14 Claw 21a Inner peripheral flange 22 Main shaft 25 Collet 26 Attachment main body 26a V-shaped groove 21, 29 Large Coupling 30 Shank 31 Pull stud 33, 40 Small diameter coupling 36 Bevel gear 39, 85 Disc spring 42 Tool spindle 80 Clamp claw member 82 Bracket 83 L-shaped clamp arm 83c Clamp claw 84 Pivot pin 86 Pin with head

Claims (1)

Attachment to the tip of the spindle head of a machine tool such as a machining center that pulls up a tool through a collet with a drawbar inserted through the center of the spindle. Attachment body provided with mating coupling that meshes with, and pull stud gripped by the collet is attached to the upper end.Flange part is formed at the lower end that has a cutout that engages with the main shaft drive key. A shank member that projects in the axial direction and has a member that bears the weight of the attachment body at the end of the shaft and that is mounted in the tapered hole at the tip of the spindle; and a member for holding the weight of the attachment body of the small diameter shaft and the attachment body. The first, which is interposed between and biases the attachment body in the pulling direction Machine member, and a coupling provided at a plurality of locations on the inner circumference of a mating coupling on the upper end surface of the attachment main body, which is swingable in a plane including the center line of the attachment main body and faces upward. An L-shaped clamp arm having a clamp claw that is removably engaged with an upper surface of an inner peripheral flange portion of the other arm facing the center of the attachment main body, and an upper surface of a distal end of the other arm abutting against a lower surface of a flange portion of the shank member; A clamp body of each L-shaped clamp arm is constantly urged in a direction of engaging with the inner peripheral flange portion, and a plurality of forces are included in the second body member which is weaker than the first body member. When it is mounted on the coupling, the clamp claw is engaged with the inner peripheral flange of the coupling together with the engagement of the coupling, the pulling up of the collet is released, and the shank member is lowered. Fastening device for a machine tool attachment, characterized by disengaging the clamp jaws of the L-shaped clamp arm by.

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