JP2000288858A - Automatic tool changing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a change time for a tool by changing the tool with rotating the tool. SOLUTION: For the purpose of allowing a change of a tool with rotating a spindle motor 40, a tool to be succeedingly used is previously rotated at a high speed with a tool rotation motor 50 in advance of the change of the tool. When the tool is changed, an ATC motor 60 is operated to rotate a rotation arm, and the tool rotated at the high speed is detached from the rotation motor 50 and is transferred to the spindle motor 40. An encoder 25 detects a rotation speed of the tool during the transfer, and the spindle motor 40 changes its rotation speed with the detected rotation speed of the tool as a center so as to allow easy insertion of the tool into the spindle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic tool changer capable of reducing a tool change time.

[0002]

2. Description of the Related Art Conventionally, in order to increase production efficiency, NC machine tools capable of performing a plurality of types of machining operations on the same work, that is, machining centers, have been used. This machining center has an automatic tool changer (hereinafter referred to as “tool changer”) that changes tools according to the type of machining operation.
ATC).

When a tool is changed using the ATC, the spindle rotating at a high speed is temporarily stopped, and after the replacement, the spindle is rotated again at a high speed to perform machining such as drilling or cutting.

[0004] Since a machining center is a machine tool characterized in that it can work efficiently, it is very important to improve the work efficiency and reduce the time required for changing tools.

For this reason, the rotation speed of the spindle is increased (tens of thousands to
(100,000 rotations) to improve work efficiency (shortening of machining time), or devising tool replacement work so as to reduce the stop time of the spindle (simplification and machining of tool replacement work) (Optimization of the order) and reduction of the time required for tool change (sudden acceleration and rapid deceleration of the spindle) by using a motor or brake having a large output for the spindle.

[0006]

However, in such a conventional ATC, when the tool is changed, the rotation of the spindle must be stopped without fail, so that rapid acceleration and deceleration of the spindle are required. A spindle motor having a large output that does not match the machining load must be used, and a brake must be provided on the spindle.

The use of a motor having a large output for the main spindle not only leads to an increase in the cost of the apparatus, but also increases the weight of the main spindle itself, resulting in a large-sized motor for moving the main spindle (for example, a linear motor or a high-speed ball screw). And the maximum moving speed of the spindle is also limited.

[0008] In a machining center, tools are frequently changed. Therefore, in order to realize efficient work, it is necessary to reduce the time required for changing tools. Just allowing the speed to decelerate limits the reduction of tool change time and does not provide a fundamental solution.

SUMMARY OF THE INVENTION The present invention has been made to fundamentally solve such problems of the conventional ATC, and it has been made possible to change a tool while rotating the tool, thereby shortening a tool changing time. The purpose is to provide an automatic tool changer.

[0010]

The present invention for achieving the above object is constituted as follows for each claim.

According to a first aspect of the present invention, there is provided a holder configured to rotatably support a tool by a bearing and detect a rotation speed of the tool by an encoder, and to provide a tool of the holder for a tool changing operation. A tool rotating means for rotating the tool in advance, a spindle rotating means for processing a workpiece by rotating a tool in the holder, and a tool rotating means for holding the holder while the tool is being rotated by the tool rotating means. The tool is removed from the tool rotating means, the tool is moved to the spindle rotating means, the tool is attached to the spindle rotating means and the holder is released, and the tool is removed from the tool rotating means by the tool changing means. A tool that calculates the rotation speed of the tool via the encoder of the holder while moving to the spindle rotating means. The rotation speed calculation means, the spindle rotation speed calculation means for calculating the rotation speed of the spindle rotation means based on the rotation speed of the tool calculated by the tool rotation speed calculation means, and the rotation speed calculation means are calculated by the rotation speed calculation means. And a driving means for driving the main shaft rotating means at a predetermined rotation speed.

According to a second aspect of the present invention, in the automatic tool changer according to the first aspect, rotation of an encoder provided on the holder is indirectly transmitted via a sensor attached to the tool changing means. Characteristically detected.

According to a third aspect of the present invention, in the automatic tool changer according to the first aspect, the holding and releasing of the holder by the tool changing means is performed by a hydraulic chuck mechanism provided in the tool changing means. Characterized in that it is configured to perform such operations.

According to a fourth aspect of the present invention, in the automatic tool changer according to the first aspect, the main spindle rotational speed calculating means centers on the rotational speed of the tool calculated by the tool rotational speed calculating means. Calculate a rotation speed that periodically fluctuates with a constant width, and periodically change the rotation phase of the spindle rotating means and the tool of the holder so that the tool is easily mounted on the spindle of the spindle rotating means. It is characterized by having done.

[0015]

According to the automatic tool changer according to any one of the first to fourth aspects of the present invention, the tool is moved from the tool rotating means to the main spindle rotating means without stopping (while being rotated). Therefore, the acceleration time of the tool can be shortened, and as a result, the working efficiency can be improved.

Further, since it is not necessary to perform acceleration in a short time, the output capacity of the spindle rotating means can be reduced, and the spindle rotating means can be downsized.

In addition, the moving means for moving the main spindle can be downsized by downsizing the main spindle rotating means, so that the machining center can be downsized and the cost can be reduced.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A tool changer according to the present invention will be described below in detail with reference to the drawings.

First, the mechanical configuration of the tool changer will be described.

[0020] The tool changer of the present invention conveys a tool to be mounted on a spindle to a tool rotation motor or stores a tool removed from the spindle in a predetermined place, and a tool supply device rotated by the tool rotation motor. A tool changer that removes the tool from the main spindle motor and moves it to the tool supply device while holding the tool with the rotating arm and moving it to the spindle motor for mounting,
A processing device for performing a processing operation on a workpiece with a tool rotated by a spindle motor.

The tool 10 used in the tool changer of the present invention
Is provided through a holder 20 as shown in FIG. 1, and is rotatably supported by a bearing (not shown) provided in the holder 10. Therefore, the tool 10 can rotate by its inertia even when the holder 20 is gripped by the rotating arm (described later).

The holder 20 has a built-in encoder (not shown) for detecting the rotational speed of the tool 10. The rotation of this encoder is read indirectly by a photoelectric sensor attached to the rotating arm.

It should be noted that all the tools 10 of the machining center
Is supported by the holder 20, so that the tool 10 can be used in all cases, such as when it is mounted on a spindle motor, when it is mounted on a tool rotation motor and it is preliminarily rotated, or when it is stored in a tool supply device. And holder 20
Is treated as one. Therefore, in the machining center exemplified in the present embodiment, there is no case where only the tool 10 is removed from the holder 20 and used.

FIG. 2 is an explanatory view of the engagement state between the tool 10 and the spindle of the spindle motor.

Although not shown in FIG. 1, a notch groove 15 as shown in FIG. 2A is provided in a portion of the tool 10 inserted into the spindle 30 of the spindle motor. On the other hand, spindle 3
A projection 35 that engages with the cutout groove 15 is provided on the inner peripheral surface of the “0”. The notch 15 and the projection 35 are
It is provided so that the spindle 30 and the tool 10 do not slip and run idle due to the processing load.

As shown in FIG. 2B, the shape of the notch groove 15 has a tapered shape in which the width increases toward the end of the tool 10.
The projection 35 engaging with 5 is simply rectangular. The reason why only the cutout groove 15 is tapered is that even when both of them are rotating at a high speed, they can be easily engaged as long as the phases are adjusted to some extent.

The tool 10 required for the next processing is taken out of the tool supply device and attached to the tool rotation motor.
Then, the tool 10 is rotated prior to the replacement operation. This rotation is performed by a tool changing motor, and the rotation speed is very high, for example, tens of thousands to 100,000 rotations / minute.

When changing a tool, a tool rotated by a tool rotation motor is gripped by a rotating arm and moved to a spindle motor to be mounted. On the other hand, a tool after machining of a workpiece is removed from the spindle motor and supplied. Use a tool changer that moves to the machine.

This tool changing device is disclosed in, for example,
As disclosed in Japanese Patent Publication No. 11821, this is generally referred to as a tool rotating arm, and is also used in a conventional machining center.

In the tool changer of the present invention, the tool is rotated at a high speed prior to the machining operation.
And remove the tool 10 from the tool rotation motor,
The tool 10 is moved to the spindle motor, and the tool 10 is mounted on the spindle 30 while aligning the notch groove 15 of the tool 10 with the projection 35 of the spindle 30 of the spindle motor.
Has been released.

In the tool changer of the present invention, the tool rotated at a high speed by the tool changer must be quickly mounted on the spindle motor rotating at a high speed. ing. Hereinafter, this device will be described in detail.

FIG. 3 is a block diagram of a control system of the tool changer according to the present invention.

The encoder 25 shown in FIG.
And is used to detect the rotational speed of the tool 10.

The spindle motor 40 rotates the tool 10 mounted together with the holder 20 when processing a workpiece, and performs desired processing. The tool 10 has an tens of thousands to 100,000 rotations during processing. Rotate at high speed for efficient machining.

The tool rotation motor 50 is a motor for rotating the tool 10 of the holder 20 in advance in preparation for a tool change operation, and rotates at a rotation speed equal to or higher than the rotation speed of the tool at the time of machining. Things.

The ATC motor 60 is a tool changing device, that is, a motor for rotating the tool rotating arm. The ATC motor 60 is rotated by rotating the tool rotating arm, from which the tool 10 attached to the tool rotating motor has been removed, to the spindle motor 40. It is to let.

The controller 70 controls the rotation speed of the spindle motor 40 based on the encoder pulse obtained from the encoder 25, rotates the tool rotation motor 50 at high speed, and controls the rotation of the ATC motor 60. is there.

The apparatus configured as described above controls the rotation speed of the spindle motor 40 as shown in the flowchart of FIG.

First, when a certain machining operation is completed and a tool insertion instruction signal is input to the controller 70 (S1),
The ATC motor 60 is rotated by 1/4, and one end of the tool rotation arm is rotated by the tool 10 rotated by the tool rotation motor 50, and the other end of the tool rotation arm is rotated by the spindle motor 40. To the tools 10 that are in use. Then, both ends of the arm firmly hold each holder 20 by the hydraulic chuck mechanism, and remove the rotating tool from the shaft of each motor.

When the removal of the tool is completed, the holder 2
0, the ATC motor 60 is further rotated by 1/2, and one arm end is connected to the main shaft 30 rotated by the main shaft motor 40, and the other arm end of the tool rotating arm is connected to the tool supply device. Approach each loader. Until the tool 10 removed from the tool rotation motor 50 is mounted on the spindle motor 40, the tool 10 is provided in the holder 20 by the photoelectric sensor attached to the arm end on the side where the tool is removed from the tool rotation motor 50. The encoder pulse from the encoder 25 is read, and is input to the controller 70 to continuously calculate the rotational speed of the tool 10.

Since the tool 10 removed from the tool rotation motor 50 is rotated only by inertia in the holder 20 from the moment of removal, the rotation speed gradually decreases as shown in FIG. 5 or FIG. Come. Controller 7
0 detects the current rotational speed of the tool 10 based on the number of encoder pulses per unit time. in this way,
The rotational speed of the tool 10 is detected because it is necessary to match the rotational speed of the spindle motor 40 with the rotational speed of the tool 10 (S2, S3).

Next, the controller 70 calculates the rotation speed of the spindle motor 40 based on the detected rotation speed of the tool 10. The rotation speed of the spindle motor 40 is
This is a rotation speed that periodically fluctuates with a constant width around a rotation speed of 0, for example, a rotation speed that fluctuates as shown by a dotted line in FIG. 5 or FIG. The reason why the rotation speed of the spindle motor 40 fluctuates is that the rotation phase of the spindle 30 and the tool 10 of the holder 20 is periodically changed so that the tool 10 is easily mounted on the spindle 30. To do that.

That is, the spindle 30 of the spindle motor of the tool 10
2A is provided in a portion to be inserted into the main shaft 30, and a projection 35 engaging with the notch groove 15 is provided on the inner peripheral surface of the main shaft 30. , Tool 1
When the tool 10 is mounted on the main shaft 30 and the rotation speed of the main shaft is changed as described above while pressing the tool 10 against the main shaft 30, the tool 10 can be used even if the phase of the notch groove 15 and the projection 35 are not surely matched. This is because it can be easily inserted into the main shaft 30 (S4).

When the tool 10 is mounted on the main shaft 30 in this manner, the tool rotating arm recognizes this and outputs a tool insertion completion signal. Therefore, until the controller 70 inputs this tool insertion completion signal, the spindle motor 4
The phase shift control for controlling the rotational speed of the tool 10 to fluctuate around the rotational speed of the tool 10 at which the rotational speed of 0 is detected is continued (S5,
S6) When the tool insertion completion signal is input, the tool 10 can be mounted on the main shaft 30. Therefore, the rotating arm releases the gripped holder 20 and makes a quarter turn, as shown in FIG. Then, the spindle motor 40 is accelerated to rotate the tool 10 at a processing speed (tens of thousands to 100,000 rotations / minute) (S7).

As described above, according to the tool changing apparatus of the present invention, the tool can be changed while the main shaft 30 is being rotated, so that the acceleration of the tool at the time of starting the machining can be reduced. The spindle motor can be made smaller than before.

Further, by reducing the size and weight of the spindle motor, the speed of the moving shaft on which the spindle motor is mounted can be increased.

Since the machining time can be shortened by increasing the rotation speed of the spindle, the tool exchange time can be made much shorter than before, and the speed of the moving shaft is also increased, thereby significantly improving the working efficiency. Will be able to do it.

As a synergistic effect of the above effects, the weight, cost and speed of the entire machining center can be reduced.

The tool changer having the above-described structure can be employed without greatly changing the structure of a conventional machining center, and therefore can be applied to an existing machining center.

[Brief description of the drawings]

FIG. 1 is an external view of a tool used in a tool changer of the present invention and a holder for supporting the tool.

FIG. 2 is an explanatory view of an engagement state between a tool used in the tool changing device of the present invention and a spindle of a spindle motor.

FIG. 3 is a block diagram of a control system of the tool changing device according to the present invention.

FIG. 4 is a flowchart showing the operation of the tool changing device according to the present invention.

FIG. 5 is an explanatory diagram of an operation of the tool changing device according to the present invention.

FIG. 6 is an explanatory diagram of an operation of the tool changing device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Tool 15 Notch groove 20 Holder 30 Main shaft 35 Projection

Claims (4)

[Claims] 1. A holder configured to rotatably support a tool by a bearing and detect a rotation speed of the tool by an encoder, and a tool rotating means for rotating the tool of the holder in advance in preparation for a tool changing operation. Spindle rotating means for processing a workpiece by rotating the tool of the holder; holding the holder while the tool is being rotated by the tool rotating means, removing the tool from the tool rotating means, A tool changing means for moving a tool to the spindle rotating means, attaching the tool to the spindle rotating means and releasing the holder, and moving the tool from the tool rotating means to the spindle rotating means by the tool changing means. Tool rotation speed calculating means for calculating the rotation speed of the tool via the encoder of the holder, Main shaft rotation speed calculating means for calculating a rotation speed of the main spindle rotation means based on the rotation speed of the tool calculated by the tool rotation speed calculation means; and the main spindle with the rotation speed calculated by the main spindle rotation speed calculation means. An automatic tool changer comprising: driving means for driving a rotating means. 2. The automatic tool changer according to claim 1, wherein the rotation of the encoder provided on the holder is indirectly detected via a sensor attached to the tool changer. apparatus. 3. The automatic apparatus according to claim 1, wherein the holding and releasing of the holder by the tool changing means is performed by a hydraulic chuck mechanism provided in the tool changing means. Tool changer. 4. The spindle rotation speed calculating means calculates a rotation speed periodically fluctuating at a constant width around the rotation speed of the tool calculated by the tool rotation speed calculation means, 2. The automatic tool changer according to claim 1, wherein the rotation phase of the tool and the tool of the holder is periodically changed so that the tool is easily mounted on the spindle of the spindle rotating means.