JP3536719B2 - Automatic tool changer - Google Patents

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 shortening a tool change time.

[0002]

2. Description of the Related Art Conventionally, in order to improve production efficiency, an NC machine tool capable of performing a plurality of types of machining operations on the same work, that is, a machining center has 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 by being able to work efficiently, it is very important to improve the work efficiency and reduce the time required for changing tools.

For this reason, the rotational speed of the spindle is increased to improve the work efficiency (shortening of machining time), or the tool replacement operation is devised so as to reduce the stop time of the spindle (for example, by changing the tool). Simplification of exchange work, optimization of machining order),
By using a motor with a large output for the spindle, the time required for tool change is reduced (rapid acceleration and deceleration of 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 with a large output that does not match the machining load must be used.

[0007] The use of a motor having a large output for the spindle not only increases the cost of the apparatus, but also increases the weight of the spindle itself, so that the size of the motor for the spindle for moving the spindle (for example, a linear motor or a high-speed ball screw) is increased. In addition, the maximum movement speed of the spindle is also limited.

In a machining center, since tools are frequently changed, it is necessary to reduce the time required for changing tools in order to realize efficient work. 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 .

[0011]

According to a first aspect of the present invention, there is provided a spindle rotating means for rotating a tool when machining a workpiece, a first tool rotating means for rotating a tool in advance in preparation for a tool changing operation, A second tool rotating means for removing the tool rotated by the spindle rotating means while rotating it;
The first tool rotating means and the second tool rotating means are attached to both ends of an arm, and a moving means rotatably supported around the center of the arm as an axis, and a tool rotated by the main shaft rotating means. Detecting the rotation speed, synchronizing the rotation speeds of the first and second tool rotation means with the rotation speed of the tool, and selecting an arbitrary position of the tool rotated by the first tool rotation means and a spindle of the spindle rotation means. any synchronize the phases of the position, while the Ru to synchronize the phases of the arbitrary position of the axis of an arbitrary position and the second tool rotating means of the tool which is rotated by the spindle rotating means, said spindle rotation means
The first and second tools because of the high rotational speed of the
The rotation speed and phase of the rotation means cannot be synchronized.
The rotation speed of the spindle rotation means
And control means for facilitating synchronization between the rotation speed and the phase .

[0013]

[0014]

[0015]

According to the first aspect of the present invention, the configuration is as described above.
According to the automatic tool changer, the tool can be moved from the tool rotating means to the main spindle rotating means without stopping (while rotating), so that the acceleration time of the tool can be shortened, and as a result, the working efficiency is improved. Will be able to do it.

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 reduced in size.

Further, the downsizing of the spindle rotating means enables the moving means for moving the spindle to be downsized, thereby enabling the machining center to be reduced in size and cost.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a tool changing device according to the present invention will be described in detail with reference to the drawings.

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

The tool changer according to the present invention includes a tool supply device for transporting a tool to be mounted on a spindle to a tool rotation motor or storing a tool removed from the spindle in a predetermined place, and a tool rotation device rotated by the tool rotation motor. While the tool is moved to the spindle motor and attached, the tool changer that removes the tool after machining of the workpiece from the spindle motor and moves to the tool supply device and the tool rotated by the spindle motor to work on the workpiece And a processing device for performing the following.

Tool 10 used in the tool changer of the present invention
Is penetrated 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 be rotated by the tool rotation motor even when the holder 20 is gripped.

It should be noted that all tools 10 of the machining center
Is supported by the holder 20, so that the tool 10 can be mounted on the spindle motor, or preliminarily rotated by mounting on the tool rotation motor, or stored in the 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
On the inner peripheral surface of the groove 0, a projection 35 that engages with the cutout groove 15 is provided. The notch 15 and the projection 35 are
The spindle 30 and the tool 10 are provided so that they do not slip and run idle due to a 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 the projections can be easily engaged only with a certain degree of phase adjustment, even when both are rotating at high speed.

The tool 10 required for the next processing is taken out from the tool supply device and is mounted on a tool rotation motor attached to one end of the tool rotation arm. Then, the tool 10 is rotated prior to the replacement operation. This rotation is
The rotation is performed by a tool changing motor, and the rotation speed tends to be higher, for example, from tens of thousands to 100,000 rotations / minute.

When changing the tool, the rotation speed of the tool rotated by the spindle motor and the rotation speed of the tool rotation motor (second tool rotation means) are made to match, and the phase of the tool and the phase of the tool rotation motor are changed. And the tool is removed from the spindle motor and mounted on the tool rotation motor. Next, the tool used for the next machining operation rotated by the tool rotating motor (first tool rotating means) is moved to the spindle motor by rotating the tool rotating arm together with the tool rotating motor, and the rotation speed of the spindle motor and The tool is mounted on the spindle motor from the tool rotation motor by matching the rotation speed of the tool with the phase of the tool and the phase of the spindle of the spindle motor.

Such an operation is performed by a tool changing device.
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. Therefore, a detailed description of the configuration is omitted here.

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

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

A spindle motor 40 shown in FIG. 1 is used for a tool 10 mounted together with the holder 20 when machining a workpiece.
Is rotated to perform desired processing, and the tool 10
Rotates at high speed during machining to perform efficient machining operations.

The tool rotation motor 50 synchronizes the tool mounted on the spindle motor 40 with the rotation of the first tool rotation motor for rotating the tool 10 of the holder 20 in advance in preparation for the tool change operation. The motor comprises two motors, a second tool rotation motor to be removed while being attached, and attached to both ends of the tool rotation arm.

When the tool is mounted on the spindle and when the tool is removed from the spindle, the tool rotation motor 50 adjusts the rotation speed and phase of the shaft of the tool rotation motor 50 to match the rotation speed and phase of the tool. It has become.

The ATC motor 60 is a motor for rotating the tool rotating arm. The ATC motor 60 is used for attaching a tool attached to the tool rotating motor 50 to the spindle 30 of the spindle motor 40, or for attaching a tool from the spindle 30 of the spindle motor 40 to the tool. This is a motor that rotates the tool rotation arm when attached to the rotation motor 50.

The controller 70 includes the tool rotation motor 50
Controlling the rotation speed and phase of the spindle motor 40 based on the rotation speed of the tool, and conversely controlling the rotation speed and phase of the tool rotation motor 50 based on the rotation speed of the spindle motor 40,
It controls the rotation of the ATC motor 60.

The apparatus configured as described above controls the rotation speed of the spindle motor 40 and the tool rotation motor 50 as shown in the flowchart of FIG. This control is described below with reference to FIG.
This will be described with reference to FIG.

At present, when the machining of the workpiece is completed by the tool attached to the spindle motor 40, machining completion information is input to the controller 70. Controller 70
Receives the information and causes the ATC motor 60 to rotate the tool rotation arm to move the tool rotation motor 50, which is the ATC tool rotation axis, to a position facing the spindle motor 40. At this point, the spindle motor 40 rotates the tool at the same rotation speed as the rotation speed at the time of machining. For this reason,
In order for the tool rotating motor 50 to receive the rotating tool, the tool rotating motor 50 must be rotated at the same rotation speed as that of the tool.
Need to be rotated. Further, it is necessary to match the phase of the tool with the phase of the rotation axis of the tool rotation motor 50. At this stage, the rotation speed of the tool rotation motor 50 is first increased to the rotation speed of the spindle motor 40 (S1).

When the rotation speed of the tool rotation motor 50 has increased to the rotation speed of the spindle motor 40, each feed shaft of the tool supply device is returned to the tool change position, and processing for removing the tool is started (S2, S3).

First, the rotation speed of the spindle motor 40 and the rotation speed of the tool rotation motor 50 are synchronized. This synchronization is performed as follows.

As shown in FIG. 5, a spindle motor rotation command value is input to a counter provided in the controller 70. The differential value of the feedback pulse (spindle current position) output from the encoder provided in the spindle motor 40 is subtracted from this command value. This subtracted value is proportionally integrated and then amplified by the amplifier 80.
The spindle motor 40 is rotated by the amplification value.

Similarly, a tool rotation motor rotation command value is input to a counter provided in the controller 70 for the tool rotation motor 50. The differential value of the feedback pulse (ATC current position) output from the encoder provided in the tool rotation motor 50 is subtracted from this command value. This subtracted value is proportionally integrated and then amplified by the amplifier 90, and the amplified value is used as the tool rotation motor 5
0 is rotated.

Therefore, to synchronize the rotation speed of the spindle motor 40 with the rotation speed of the tool rotation motor 50, the same value as the spindle motor rotation command value may be input to the tool rotation motor rotation command value. For this reason, the controller 70
Recognizing the value currently input to the counter as the spindle motor rotation command value, detecting the rotation speed of the spindle motor, and setting the counter value for the tool rotation motor to the same value as the spindle motor rotation command value ( S4).

When the rotation speed of the spindle motor 40 matches the rotation speed of the tool rotation motor 50 as described above, the phase of the spindle of the spindle motor 40 and the rotation speed of the tool rotation motor 50
And the phase of the axis. In this phase matching, as shown in FIG. 2, the tool cannot be inserted into the shaft of the tool rotating motor 50 unless a specific phase relationship is established, as in the case of aligning the notch groove 15 of the tool with the projection 35 of the shaft. This is because This phase adjustment is performed as follows.

The encoder pulse (spindle current position) output from the encoder of the spindle motor 40 and the encoder pulse (A) output from the encoder of the tool rotation motor 50
TC current position) is input to the phase matching circuit 100 shown in FIG. 5, and when the phases of both motors are different, a pulse corresponding to the phase difference is output from the phase matching circuit 100 to the spindle motor command value or tool rotation. It is added to the motor rotation command value. For this reason, the rotation speed of one of the motors is temporarily reduced, and the phases of the axes of both motors are matched (S5).

When the phase matching process is performed as described above, it is determined whether or not the rotation speed and the phase of the spindle motor 40 and the tool rotation motor 50 are synchronized (S6), and the synchronization is performed. If the tool is
The tool is moved from the main spindle 30 to the axis of the tool rotation motor 50, and the tool is removed from the main spindle 30 (S7).

When the tool is removed from the spindle 30 in this manner, the ATC motor 60 rotates the tool rotation arm to position the tool rotation motor (first tool rotation motor) 50 so as to face the spindle motor 40. Tool rotation motor 50
Has already rotated the tool at the same rotation speed as that of the spindle motor 40 at this time,
Performs exactly the same processing as the processing in step S4 to synchronize the rotation speed of the spindle motor 40 with the rotation speed of the tool rotation motor 50 (S8, S9).

When the rotation speed of the spindle motor 40 and the rotation speed of the tool rotation motor 50 match, the same processing as that in step S5 is performed, and the phase of the spindle of the spindle motor 40 and the axis of the tool rotation motor 50 are determined. (S1)
1).

When the phase matching process is performed in this way, it is determined whether or not the rotation speed and the phase of the spindle motor 40 and the tool rotation motor 50 are synchronized (S12), and the synchronization is performed. Then, the tool is moved from the axis of the tool rotation motor 50 to the spindle 30 of the spindle motor 40, and the tool is attached. When the installation of the tool is completed, the spindle motor 40 immediately starts working (S13).

As described above, according to the automatic tool changer according to the present invention, the tool can be attached and detached while the spindle motor 40 is rotating. And can be shortened as shown in FIG.

That is, in the conventional tool changer, FIG.
As shown in (1), while the tool rotating arm (ATC main body) is rotating and the tool is attached to or detached from the main spindle as shown by a straight line B, the rotational speed of the main spindle is temporarily reduced to zero as shown by a straight line A. After dropping and changing tools, the machine accelerates to the rotational speed at the time of machining when entering machining work. However, in the automatic tool changer of the present invention, the spindle motor 4 is rotated in a state where the tool rotation motor 50 rotates the tool as indicated by a straight line C.
Since the tool can be attached to or removed from the main spindle, the tool rotation arm (ATC main body) rotates and the main spindle can be attached or detached as shown by the straight line B while the tool is attached to or removed from the main spindle. Is constant as shown by the straight line A. Therefore, the acceleration / deceleration time of the spindle can be saved, and the machining time can be shortened accordingly.

In the above-described embodiment, the description has been made on the assumption that the tool rotation motor 50 can be synchronized with the spindle motor 40. However, since the rotation speed of the spindle motor 40 is high, synchronization cannot be performed well ( In the case of synchronous NG), the rotation speed of the spindle motor 40 is reduced as shown by the straight line A only when the tool is changed as shown in FIG.
After making it easy to synchronize the rotational speed with 0 and the phase, the tool is replaced, and after the tool is replaced, the spindle motor 40 is accelerated to the rotational speed at the time of machining.

As described above, when the synchronization is not achieved, if the rotation speed of the spindle motor is reduced once, the synchronization of the tool rotation motor 50 becomes easy, and the acceleration after the tool change is slightly smaller than the conventional one. Therefore, the advantage of shortening the processing time can be maintained.

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. Therefore, the acceleration of the tool at the time of starting the processing is small. 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. As a result, the work efficiency is significantly improved. Will be able to do it.

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

[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 a diagram for explaining the operation of the tool changing device according to the present invention.

FIG. 6 is a diagram for explaining the operation of the tool changing device according to the present invention.

FIG. 7 is a diagram for explaining the operation of the tool changing device according to the present invention.

FIG. 8 is a diagram for explaining the operation of the tool changing device according to the present invention.

[Explanation of symbols]

10 Tools 15 Notch groove 20 holder 30 spindle 35 protrusion

Claims (1)

(57) [Claims] 1. A spindle rotating means for rotating a tool when machining a workpiece, a first tool rotating means for rotating a tool in advance in preparation for a tool changing operation, and a rotation by the spindle rotating means during a tool changing operation. Second tool rotating means for removing the tool while being rotated, the first tool rotating means and the second tool rotating means are attached to both ends of an arm, and are supported rotatably about the center of the arm. Moving means for detecting the rotation speed of the tool rotated by the main spindle rotation means, and synchronizing the rotation speeds of the first and second tool rotation means with the rotation speed of the tool; The phase of an arbitrary position of the tool rotated by the main shaft rotating means and the arbitrary position of the main shaft of the main spindle rotating means are synchronized, and the arbitrary position of the tool rotated by the main spindle rotating means and the second tool rotation One of Ru to synchronize the phases of the arbitrary position of the shaft means
On the other hand, because the rotation speed of the spindle rotating means is high,
The rotation speed and the phase of the first and second tool rotation means are the same.
If it is not possible to take the
The rotation speed is once decreased to make the rotation speed and the phase equal.
An automatic tool changer comprising: control means for facilitating a period .