JPH0118275Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a tool changing arm in an automatic tool changing device of a machine tool, such as a machining center.

Prior Art In general, a tool exchange arm requires sliding in the axial direction beyond the length of the shank of the tool in order to attach and detach the tool to the spindle, and also requires rotation to exchange the tool, and the twin arm type requires 180° sliding movement in the axial direction. rotation is required. For this reason, the pivot shaft of the arm has a spline fitting part, and a clearance for sliding is provided. When the tool or tool holder (hereinafter referred to as the tool) is attached to the spindle, it must rotate together with the spindle, so the drive is designed so that the keyway fits in the flange on the tool side without any gaps on the spindle side. A key is provided. When changing the tool, the spindle is angularly indexed to a positioning position, and one gripper of the exchange arm is set so that the key groove of the tool holder is at a constant angle position.When the tool is transported and installed in the spindle hole, the spindle's drive key is is fitted into the keyway of the tool flange.

Problems that the invention aims to solve: However, even if the drive system parts of the replacement arm are manufactured within manufacturing tolerances, depending on how the errors appear, they add up and become large, appearing as gaps in the rotation direction of related parts such as the rotation axis. Or, if the tool has become loose due to wear due to use, when the tool gripped by the tool change arm is attached to the spindle, the swing arm may be slightly deviated from the normal swing angle position and the keyway edge of the tool flange may This may cause a problem where the replacement arm comes into contact with the drive key of the main shaft, producing a sound, or collides with the main shaft drive key, causing the replacement arm to stop on the spot without mating, which may hinder work. Therefore, the present invention seeks to provide an angular positioning device for a tool changing arm that solves the above problems.

Means for Solving the Problem A protrusion 10a is provided at one location on the circumference of the pivot shaft 3 of the tool changing arm 1, and a guide groove 14a that slides into the member that supports the pivot shaft 3 is fitted with the protrusion. ,14
b is cut at two locations in the circumferential direction, and the protruding portion 10a of the pivot shaft guide 10 is cut just before the keyway Ta of the tool flange and the drive key 13 of the main shaft 12 are fitted together.
and a guide groove are fitted, and when the key groove and the drive key are fitted, the protrusion is positioned such that it passes through the guide groove.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings. The machining center (not shown) is assumed to be vertical, and the exchange arm for exchanging the tool in the magazine or the tool conveyed to the ready station with the tool in the spindle is exemplified as a twin arm type. The exchange arm 1 has grippers 2 at both ends for gripping a grip groove Ta in the flange portion of the tool T, and a pivot shaft 3 is attached to the center of the arm. The pivot shaft 3 is supported by a bracket 5 of the arm support 4 via a flat bearing, and a male spline is cut into the spline 3a of the pivot shaft 3, and a bracket 6 of the arm support 4 is supported by the bracket 5 of the arm support 4.
A female spline of a gear 8 supported by bearings 7, 7 is fitted. The gear 8 meshes with a swing rack 9 driven by a piston of a hydraulic cylinder (not shown). At the base of the spline 3a of the pivot shaft 3, as shown in FIG. 2, there is a pivot shaft having a protrusion 10a at one location on the outer periphery with a long parallel width in the axial direction and with chamfered ends in the axial direction as shown in FIG. A guide 10 is fixed by two keys 11 and a taper pin 16. When the tool T is attached to the main shaft 12 with the exchange arm 1, the protrusion 10a of the pivot guide 10 is inserted into the key groove of the flange of the tool T.
In order to hold the exchange arm 1 at an accurate angle in front of the drive key 13 at the end of the main shaft 12, a fixed guide 14 is attached to the end surface of the bracket 6 concentrically with the pivot shaft 3, as shown in FIG. It is selectively slidably fitted into guide grooves 14a or 14b cut at 180° symmetrical positions. When the shank of the tool T is completely attached to the main shaft, the protrusion 10a is positioned in the state shown in FIG. 1, having passed through the guide groove 14a or 14b of the fixed guide 14. After this, the exchange arm 1 is rotated at an angle within 90 degrees to wait in a position where it does not interfere with the work around the main shaft.
The turning guide 10 can turn together with the turning shaft 3 without interfering anywhere. Furthermore, when the exchange arm 1 completely pulls out the tool T from the main shaft 12, the protrusion 10a of the pivot shaft guide 10 is located at both end surfaces of an arc-shaped stopper 15 that is concentric with the pivot shaft fixed to the end of the bracket 5 of the arm support 4. It has the role of a dog that determines the end position of the 180° rotation of the exchange arm 1 by coming into contact with one of them. The tip (not shown) of the pivot shaft 3 is integrated with a piston of a hydraulic cylinder (not shown), moves in the axial direction, and is positioned at two positions: tool mounting and tool extraction. It goes without saying that this device can also be applied to a single arm type.

Operation When a tool exchange command is issued, the main spindle 12 moves from the working position to the exchange position, the ready station receives tools from the magazine, and the exchange arm is at the leftward position and the standby angle position in the figure. The turning rack 9 is moved by the action of the hydraulic cylinder, the turning shaft 3 is turned by the gear 8, and the main shaft 12 and the tool T of the ready station are gripped by the gripper 2. Due to the action of the hydraulic cylinder, the pivot shaft 3 moves to the right in the figure and pulls out the tool T. Next, the swinging rack 9 moves again to swing the exchange arm 1 through 180 degrees, and the protrusion 10a of the swing shaft guide 10 is brought into contact with the other end of the stopper 15 and positioned. Next, the rotation axis 3 is moved to the left in the figure, the tool T faces the tapered hole of the main spindle 12, and the drive key 13 is inserted into the key groove of the tool T.
Before facing Ta, the protrusion 10a of the pivot guide 10
is smoothly fitted into the guide groove 14a or 14b of the fixed guide 14 from the chamfered part, and the replacement arm 1 is positioned at an accurate angle by sliding the parallel part of the protruding part 10a.
At this position, the drive key 13 of the spindle 12 is
It fits smoothly without colliding with the keyway Ta. At the position where the shank of the tool T is completely attached, the protrusion 10a of the pivot shaft guide 10 is connected to the fixed guide 14.
The fitting is separated so that there is no support for the turning of the turning shaft 3. The pivot shaft 3 then pivots, the gripper 2 is removed, and the exchange arm 1 returns to the standby position.

Effects As detailed above, the present invention provides a protrusion on the pivot shaft and a guide groove that fits into the protrusion on the pivot shaft support member, so that the drive key of the spindle slides just before it fits into the keyway of the tool. Since it is made to fit together, there is no gap in the rotation direction of the rotation axis of the exchange arm,
This has the effect of preventing the replacement arm from stopping midway and interrupting the operation due to contact noise or collision between the drive key and the tool flange portion, thereby enabling highly reliable continuous operation.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the invented part of the tool change arm, Figure 2 is a plan view of the pivot guide, and Figure 3 is a cross-sectional view of the invented part of the tool change arm.
The figure is a view from A-A in Fig. 2, and Fig. 4 is a view from B-A in Fig. 1.
This is a view from B. DESCRIPTION OF SYMBOLS 1... Replacement arm, 3... Swivel shaft, 8... Gear, 9... Swivel rack, 10... Swivel shaft guide, 10a... Projection, 12... Main shaft, 13...
Drive key, 14...Fixed guide, 14a, 1
4b...Guide groove, T...Tool.

Claims (1)

[Scope of utility model registration request] A protrusion is provided at one location on the pivot shaft of the tool exchange arm that is supported so as to be able to rotate and slide in the axial direction, and guide grooves that slide into the protrusion are provided at two locations in the circumferential direction on the pivot shaft support member. , When the tool is attached to the spindle with the tool exchange arm, the protrusion is fitted into the guide groove immediately before the key groove of the tool and the drive key of the spindle are fitted, and the key groove and the drive key are fitted. An angular positioning device for a tool changing arm, characterized in that the protruding portion is positioned so as to pass through the guide groove.