JP2782300B2 - Tool change mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool exchanging mechanism of a tool exchanging arm unit for turning and exchanging a tool exchanging arm of a machine tool such as a machining center.

[0002]

2. Description of the Related Art Conventionally, there has been a system in which a tool changing arm of a tool changing arm unit of a machining center uses a cam to rotate and insert / remove a tool changing arm. As shown in FIG. 9 and FIG.
The rotation of the drive shaft 103 via the speed reducer 102 causes the shift cam 104 to insert and remove the tool change arm 105 in the turning axis direction, and the roller gear cam 106 and the cam follower 107 to turn the tool change arm 105. It is.

[0003]

The method described in the prior art, in which the exchange operation is performed by a cam, is problematic in that the machining of the cam is difficult, the structure is complicated, the frequency of malfunctions is high, and the cost is increased. Had a point. The present invention has been made in view of such problems of the prior art, and has as its object the purpose of one drive motor, a simple structure with few components, high-speed stabilization of operation and cost reduction. It is an object of the present invention to provide a tool changing mechanism capable of achieving reduction.

[0004]

In order to achieve the above object, a tool changing mechanism according to the present invention performs a tool change by turning a tool changing arm at the center between a main shaft and a tool pot and by inserting / removing in a direction of an arm center axis. A tool changing arm unit mechanism for: a screw provided on a frame of the tool changing arm unit so as to be concentric and rotatable with the arm center axis and driven by a variable speed motor; and a rear end of the arm center axis. A nut member concentrically fitted to the portion and screwed to the screw and having a clutch claw at each end and an engagement piece on the outer periphery; and a notch engraved in a hole into which the arm central axis of the frame is fitted. A series of guide grooves bent in the axial direction and the circumferential direction in which the engagement piece is slidably engaged, a spring for preventing inversion provided at each bent portion of the guide grooves, and both ends of the screw; Axial shift to The two-way type two-way clutch is provided so as to be able to engage with the clutch claw at the axially moving end of the nut member, and to be urged by a spring provided at both ends of the screw. And

[0005]

When the engaging piece on the outer periphery of the nut is engaged in the circumferential guide groove formed in the hole into which the arm center axis of the frame is inserted, the nut is not attached to the shaft. Since the directional movement is regulated, the tool is rotated together with the screw, and the turning operation of the tool changing arm is performed. When the engaging piece is engaged in the guide groove in the axial direction, the rotation of the nut is restricted, so that the nut is moved in the axial direction by the rotation of the screw, so that the tool changing arm is inserted and removed. . When there is an engaging piece at the bending point of the guide groove, the spring prevents the tool change arm from reversing due to an imbalance in the weight of the gripping tool, and the one-way pawl clutch at both ends of the screw engages one of the claws at both ends of the nut. And the direction of the engagement piece is smoothly changed.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described with reference to FIGS. In the machining center shown in FIG. 6, the table 2 is mounted on the X-axis guide provided on the front side of the bed 1 so as to be movable and positionable, and the column 3 is mounted on the Z-axis guide on the rear side of the bed 1 so as to be movable and positionable. Is placed. A spindle head 4 is movably mounted on a Y-axis guide provided on the front surface of the column 3, and a spindle 5 is rotatably supported on the spindle head 4. Further, a tool magazine 6 is installed on the left floor of the column 3, and a table 10 attached to the magazine 6 is provided.
A transfer arm 8 for transferring the tool pot 7 from the tool magazine side change position to the spindle side standby position is provided so as to be able to turn 90 ° in a horizontal plane, and a tool change arm unit shown in FIG. 9 are attached.

The frame 11 of the tool change arm unit 9 is provided with a hole 11a in the Z-axis direction, and a cylindrical arm center shaft 13 having a tool change arm 12 at the tip thereof is turned and rotated in the hole 11a. It is fitted so as to be movable in the axial direction.
Further, a screw 14 is rotatably supported on the frame 11 concentrically with respect to the hole 11a. The screw 14 is formed as a left-handed screw, and a gear 15 is fitted to the rear end. The gear 15 meshes with a gear 17 fitted on an output shaft of a variable speed motor 16 fixed to the frame 11, and the variable speed motor 16 has a position detector 18.
Are mounted concentrically.

A nut 19 screwed to the screw 14 is fitted to the rear end of the arm center shaft 13 via the housing 21, and clutch claws 21 are provided at both ends of the housing 21.
a and 21b are provided integrally. Claw clutches 22 and 23 integrally having claws 22a and 23a on both sides of the screw portion are inserted into the screw 14 so as to be movable only in the axial direction. The claw clutches 22 and 23 are provided with springs 24 and 25, respectively.
, Are always urged toward the claws 22a and 23a, respectively. FIG. 5 is a perspective view showing the shape of the claw 22a, which has the same lead angle as the screw 14 and rotates the screw 14 clockwise (the motor 1).
When viewed from the side (6), the one-way clutch is capable of transmitting a rotational force to the claw 21a, and the claw 23a is also formed in a similar shape.

In the hole 11a of the frame body 11, as shown in FIG.
And a circumferential guide groove 28 connecting the front ends (left ends) of the guide grooves 27 and 29, and a substantially 90 ° circumferential guide groove 26 and a guide connected to the rear end (right end) of the guide groove 27. An approximately 90 ° circumferential guide groove 30 connected to the rear end of the groove 29 is formed as a series of bent guide grooves. An engaging piece 31 projecting on the outer periphery of the housing is slidably engaged in the guide grooves 26 to 30. Further, the frame 11 is provided with four radial through holes near the bending points of the guide grooves 26 to 30, and plate springs 32 to 35 for preventing inversion are formed in the through holes as shown in FIG. They are mounted in the states shown in FIGS.

Next, the operation of the embodiment will be described with reference to the operation numbers (1) to (5) of FIGS. When the tool change arm 12 is in the horizontal standby state, the engagement piece 31 is at the point A, and the claw 23a of the claw clutch 23 and the claw 2 of the housing 21 are set.
1b is in the engaged state. Screw 1 by variable speed motor 16
4 is rotated to the left (as viewed from the motor 16 side), the engaging piece at the point A moves (1) toward the point B along the circumferential guide groove 26, and the leaf spring 32 is inclined. The plane spring 32 gets over from the side 32b to reach the point B, and the leaf spring 32 restricts reverse rotation. During this time, the tool exchanging arm 12 turns by approximately 90 °, and simultaneously grasps the current tool of the main shaft 5 and the next tool of the tool pot 7 at the standby position by the grasping claws at both ends.

The reverse rotation of the engagement piece at the point B is restricted by the leaf spring 32, and the axially forward (left) movement is enabled by the guide groove 27. It moves (2) toward the point C along the guide groove 27,
The vehicle reaches the point C in a state where the clockwise rotation is not restricted by passing over the leaf spring 33 from the inclined surface 33a side, and the pawl 21a engages with the pawl 22a of the pawl clutch 22. During this time, the tool exchange arm 12 holding the two tools extends in the direction of the arm center axis 13 and extracts both tools from the main shaft 5 and the tool pot 7. Since the engaging piece 31 at the point C can be moved in the circumferential direction by the guide groove 28, it moves toward the point D by turning the screw 14 clockwise (3), gets over the leaf spring 34, and reversely rotates. Reaches the point D in a state where is regulated. During this time, the tool change arm 1
2 rotates 180 °, and the positions of the next tool to be gripped and the current tool are switched.

The reverse rotation of the engagement piece 31 at the point D is restricted by the leaf spring 34, and the axial movement to the rear side (right side) is enabled by the guide groove 29.
The plate spring 35 is moved toward the point E (4), and the leaf spring 35 is
The vehicle gets over from the side a and reaches the point E (4), the reverse rotation is restricted, and the pawl 21b is engaged with the pawl 23a of the pawl clutch 23.
During this time, both tools to be gripped are simultaneously inserted into the spindle 5 and the tool pot 7. Since the engagement piece 31 at the point E can be moved clockwise in the circumferential direction by the guide groove 30, the engagement piece 31 moves toward the point F by rotating the screw 14 clockwise (5). During this time, the tool change arm 12 turns by approximately 90 °, separates from both tools, and returns to the horizontal standby state. The next tool change operation is performed in the reverse order of (6) to (10).

[0013]

Since the present invention is configured as described above, the following effects can be obtained. A single variable speed motor and a set of screws and nuts allow the tool changing arm to be turned and inserted / removed, so that a simple tool changing mechanism with a small number of parts can be obtained, and stable high speed operation can be obtained at low cost.

[Brief description of the drawings]

FIG. 1 is a sectional view of a side surface of a tool changing unit according to the present embodiment.

FIG. 2 is a sectional view taken along line GG of FIG. 1, showing a mounting posture of a plate spring for preventing reverse rotation.

FIG. 3 is a sectional view taken along line HH of FIG. 1, showing a mounting posture of a reverse rotation preventing leaf spring.

FIG. 4 is a perspective view of a plate spring for preventing reverse rotation.

FIG. 5 is a perspective view of only a claw portion of the claw clutch.

FIG. 6 is a view of a machining center.

FIG. 7 is a diagram illustrating an operation sequence of the present embodiment.

FIG. 8 is a view showing a development view of a guide groove and an operation order.

FIG. 9 is a cross-sectional view of a conventional cam type tool changing unit.

FIG. 10 is a sectional view of a conventional cam type tool changing unit.

[Explanation of symbols]

9 Tool changing arm unit 11 Frame 11a hole 12 Tool changing arm 13 Arm center axis 14 Screw 16 Variable speed motor 19 Nut 21 Housing 22, 23 Claw clutch 21a, 21b, 22a, 23a Claw 24, 25 Spring 31 Engagement piece 26 -30 Guide groove 32-35 Leaf spring

Claims (1)

(57) [Claims] A mechanism of a tool changing arm unit for performing tool changing by turning a tool changing arm at a center between a main shaft and a tool pot and inserting and removing the tool in a direction of a center axis of the arm, wherein a frame of the tool changing arm unit is provided. A screw provided concentrically with and rotatable with the arm center shaft and driven by a variable speed motor; and a clutch claw fitted at the rear end of the arm center shaft and screwed to the screw and at both ends thereof. And a nut member having an engaging piece on the outer periphery, and an axial direction and a circumferential direction in which the engaging piece is engraved in a hole into which the arm central axis of the frame is inserted and slidably engaged. A series of bent guide grooves, a reversing prevention spring provided at each bent portion of the guide grooves, and an axially movable end of the nut member provided at both ends of the screw so as to be movable only in the axial direction. Nails and hooks A tool changing mechanism comprising: two one-way type pawl clutches which are urged to engage freely by springs provided at both ends of the screw.