JP3694777B2 - Tool change method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a machine tool, for example, a machining center, a spindle that is rotatably supported by a spindle head that can move at least in the X-axis direction and the Y-axis direction perpendicular to the Z-axis direction that is the spindle axis direction, and a predetermined trajectory. The present invention relates to a method for exchanging a tool with a tool gripping means that has a plurality of tool gripping portions that move and moves closer to and away from the main axis in the Z-axis direction.
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, the following two methods are known as a tool change method in a machining center.
[0003]
The first method is a method using a tool changer arm having two tool grippers which are provided so as to be rotatable around an axis parallel to the Z-axis direction and extend radially from the rotation center axis to form a predetermined angle with each other. It is. In this method, first, when the work using the tool attached to the spindle is completed, the spindle is moved to the tool change position, and the tool is held at the tool attachment / detachment position of the tool change arm by one tool gripper. Hold it. The other tool gripper of the tool change arm holds and grips the next tool used for the next work from the tool magazine. Next, the main shaft and the tool exchange arm are relatively separated from each other in the Z-axis direction, and the tool is pulled out from the main shaft. Next, the tool changing arm is rotated by a predetermined angle, and the tool gripper holding the next tool is brought to the tool attaching / detaching position. Thereafter, the main shaft and the tool change arm are relatively moved in the Z-axis direction, and the next tool is inserted into the main shaft. In this way, the tool is changed.
[0004]
The second method is a method of delivering a tool directly between the spindle and the tool magazine without using a tool changing arm. In this method, first, when the work using the tool attached to the spindle is completed, the spindle is moved to the tool changing position, and the tool is held by the tool holding unit waiting at the tool attaching / detaching position of the tool magazine. . Next, the spindle and the tool magazine are relatively separated in the Z-axis direction, and the tool is pulled out from the spindle. Next, the tool magazine is driven, and the tool gripping part that grips the next tool is moved to the tool attaching / detaching position. Thereafter, the main shaft and the tool magazine are relatively moved in the Z-axis direction, and the next tool is inserted into the main shaft. In this way, the tool is changed.
[0005]
However, in the above-described two methods, since the insertion / extraction of the tool to / from the spindle and the rotation of the exchange arm or the movement of the tool gripping portion of the tool magazine are performed separately, the time required for the tool change becomes long. was there.
[0006]
Therefore, in order to shorten the tool change time, in the first method, it is considered that the relative movement in the Z-axis direction between the spindle and the tool change arm overlaps with the rotation of the tool change arm. ing. This method will be described with reference to a time chart shown in FIG. In this description, it is assumed that only the main shaft moves in the Z-axis direction. First, when the work using the current tool attached to the spindle is completed, the spindle is moved to the tool change position, and the current tool is gripped by one tool gripper waiting at the tool removal position of the tool change arm. . The other tool gripper holds the next tool extracted from the tool magazine. Next, the spindle is linearly moved from the tool insertion position toward the tool removal position so as to be separated from the tool change arm in the Z-axis direction. After a lapse of a predetermined time from the start of this linear movement of the spindle, the rotation of the tool changing arm is started, and the tool gripper holding the current tool is moved on a predetermined path so as to move away from the tool attachment / detachment position. While moving the spindle straight to the tool removal position, the tool is pulled out of the spindle. The spindle is stopped at the tool removal position. The tool change arm further rotates, and before the tool gripper holding the next tool reaches the tool detachment position, the main axis starts moving in the Z-axis direction, and the tool change arm moves from the tool removal position toward the tool insertion position. Against the Z-axis direction. As a result, the tool gripper holding the next tool is moved on a predetermined track so as to approach the tool detachment position, and the spindle is linearly moved to the insertion position to insert the tool into the spindle. In this way, the tool is changed.
[0007]
Although detailed explanation is omitted, also in the second method, in order to shorten the tool change time, the relative movement in the Z-axis direction between the spindle and the tool magazine is changed between the tool gripping portion of the tool magazine. It is considered to overlap.
[0008]
However, in the improved method described above, the spindle and the tool interfere with each other when the tool is inserted into and removed from the spindle. Therefore, when the tool is pulled out from the spindle, the movement start time and movement of the tool gripping portion of the tool exchange arm or the tool magazine are removed. There is a limit to advancing the end time. Similarly, when a tool is inserted into the spindle, there is a limit to advancing the approach start timing in the Z-axis direction with respect to the tool exchange arm or tool magazine of the spindle, and the tool insertion into the spindle cannot be finished early. . Therefore, there is a limit to the effect of shortening the tool change time.
[0009]
An object of the present invention is to provide a tool changing method that solves the above problems and can shorten the tool changing time as compared with the conventional method.
[0010]
[Means for Solving the Problems]
The tool changing method according to the first aspect of the invention is a spindle that is rotatably supported by a spindle head that is movable in at least one of an X-axis direction and a Y-axis direction that are orthogonal to the Z-axis direction that is the spindle axis direction. And a tool gripper that has a tool gripper that moves on a predetermined track and that can approach and separate in the Z-axis direction relative to the main shaft, When pulling out the spindle from the spindle, the tool gripper grips the tool attached to the spindle, and then the spindle moves with the tool gripper along the trajectory where the tool gripper that grips the tool moves away from the tool removal position. The tool is pulled out from the main shaft by separating the main shaft and the tool gripping means relatively in the Z-axis direction.
[0011]
A tool change method according to a second aspect of the present invention is a spindle that is rotatably supported by a spindle head that is movable in at least one of an X-axis direction and a Y-axis direction that are orthogonal to the Z-axis direction, which is the axis direction of the spindle. And a tool gripper that has a tool gripper that moves on a predetermined track and that can approach and separate in the Z-axis direction relative to the main shaft, When the spindle is attached to the spindle, the spindle and the tool gripping means are moved while moving the spindle along with the tool gripper along a trajectory that moves so that the tool gripping part that holds the tool to be attached to the spindle approaches the tool attachment / detachment position. The tool is inserted into the main shaft by relatively approaching in the Z-axis direction.
[0012]
3. The tool change method according to claim 1 or 2, wherein the tool gripping means includes a tool change arm having a tool gripper provided rotatably around an axis parallel to the Z-axis direction, and a plurality of tool grips. A tool magazine having a section is used.
[0013]
According to the tool exchanging method of the first aspect of the present invention, when the vacant tool gripping portion of the tool gripping means comes to the tool detaching position where the tool can be gripped and released, the tool gripping portion is attached to the spindle. The tool and gripper are moved relative to each other while moving the spindle along with the tool gripper along the trajectory where the tool gripper that grips the tool moves away from the tool attachment / detachment position. Since the tool is pulled out from the main shaft by being separated in the axial direction, the movement of the tool gripping part that grips the tool away from the tool attaching / detaching position can be started earlier than the conventional method. Therefore, tool change time can be shortened compared with the conventional method.
[0014]
According to the tool changing method of the invention of claim 2, before the tool gripping part that grips the tool to be attached to the spindle comes to the tool detaching position, the tool gripping part that grips the tool approaches the tool detaching position. The tool is inserted into the spindle by relatively moving the spindle and the tool gripping means in the Z-axis direction while moving the spindle along with the tool gripper along the moving trajectory. Relative approach in the axial direction can be started earlier than in the conventional case, and as a result, tool insertion into the main spindle can be finished early. Therefore, tool change time can be shortened compared with the conventional method.
[0015]
Next, according to the method of the present invention, two tool grippers in which the tool gripping means is provided so as to be rotatable around an axis parallel to the Z-axis direction and extend radially from the rotation center axis to form a predetermined angle with each other. A time chart shown in Fig. 3 (b) for the case where the main tool moves only in the Z-axis direction and the current tool is pulled out and the next tool is attached continuously. Will be described with reference to FIG.
[0016]
First, when the work using the current tool attached to the spindle is completed, the spindle is moved to the tool change position, and the current tool is gripped by one tool gripper waiting at the tool removal position of the tool change arm. . The other tool gripper holds the next tool extracted from the tool magazine. Next, the spindle is linearly moved from the tool insertion position toward the tool removal position so as to be separated from the tool change arm in the Z-axis direction. After a lapse of a predetermined time from the start of the movement of the spindle, first, the spindle is moved away from the tool attachment / detachment position along a trajectory in which the tool gripper holding the current tool moves away from the tool attachment / detachment position, Next, rotation of the tool changing arm is started, and the tool gripper is moved on the track so as to move away from the tool attaching / detaching position. When the tool gripper moves, the spindle moves with the tool gripper along the track. The main shaft moves along the track to a position away from the tool removal position by a predetermined distance, and then moves in the opposite direction along the same track toward the tool removal position. When the main shaft moves along the track to a position away from the tool attachment / detachment position by a predetermined distance, the tool and the tool held by the tool gripper do not interfere with each other in the Z-axis direction. During the movement of the main shaft along the track and the rotation of the tool arm, the main shaft is moved straight to the tool removal position, and the extraction of the current tool from the main shaft is completed. The straight movement of the spindle in the Z-axis direction is stopped at the tool removal position.
[0017]
Thereafter, the movement of the main shaft on the track and the rotation of the tool changing arm are continued. Due to the rotation of the tool changing arm, the gripper holding the next tool moves on the track toward the tool detaching position. Z axis direction of the spindle that approaches the tool change arm after a lapse of a predetermined time after the spindle starts moving in the direction away from the tool attachment / detachment position in the direction opposite to the first movement direction after passing the tool attachment / detachment position along the track. Start moving straight ahead. After a predetermined time has elapsed after the linear movement of the spindle in the Z-axis direction starts, the spindle is moved from the tool attachment / detachment position along the track before the tool gripper holding the next tool reaches the tool attachment / detachment position. Since the position reaches a distance, the movement of the main shaft along the trajectory is stopped here. When the tool gripper gripping the next tool reaches a position corresponding to the main shaft whose movement along the track is stopped, the main shaft is moved along with the tool gripper again toward the tool attaching / detaching position along the track. Let Then, the insertion of the next tool into the spindle is started during the movement of the tool gripper and the movement of the spindle along the trajectory. Then, after stopping the movement of the tool gripper on the track and the movement of the spindle along the track on the tool changing arm, if the linear movement of the spindle in the Z-axis direction so as to approach the tool changing arm is continued, The insertion of the tool into the spindle is complete. In this way, the tool is changed. According to this method, as is apparent from FIG. 3, the movement of the tool gripper holding the tool away from the tool attaching / detaching position for the time t1 can be started earlier than the conventional method. Further, the Z axis direction approach to the tool change arm of the main spindle can be started earlier than the conventional case only at time t2, and as a result, the tool insertion into the main spindle can be ended earlier by time t3. Therefore, the time required for tool change is shortened.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In the following description, the top and bottom, left and right in FIG. 1A are referred to as top and bottom, and left and right, respectively, and the left side in FIG.
[0019]
In this embodiment, a tool is exchanged between the main shaft and the tool exchange arm.
[0020]
The main shaft (1) is a main shaft head that can move in the Z-axis direction (front-rear direction), which is the axial direction of the main shaft, and in the X-axis direction (left-right direction) and Y-axis direction (up-down direction) orthogonal (Not shown) is rotatably supported. (1a) is a drive key for rotating the tool (T). The tool change arm (2) is provided so as to be rotatable about an axis parallel to the Z-axis direction and extends in a radial direction from the rotation center axis to form a predetermined angle with respect to each other, in this embodiment, 180 degrees. It has grippers (2A) (2B). The tool change arm (2) is rotated at an arbitrary angle by an appropriate drive means, in this embodiment a servo motor (3), and has a tool gripper (4A) at the tip of the tool gripper (2A) (2B). (4B) moves on a circular orbit (W) located on the XY plane.
[0021]
When exchanging the tool (T) between the spindle (1) and the tool change arm (2), first, when the work using the current tool (T) attached to the spindle (1) is completed, the spindle (1) is moved to the tool change position, and the current tool (T) is held by the tool holding part (4A) of one tool gripper (2A) waiting at the tool removal position of the tool change arm (2) ( (See FIG. 1). The next tool (T) is extracted from the tool magazine and is gripped by the tool gripping portion (4B) of the other tool gripper (2B).
[0022]
Next, the spindle (1) is moved straight backward from the tool insertion position (the position indicated by the solid line in FIG. 1 (b) and FIG. 2) toward the tool removal position (the position indicated by the chain line in FIG. 1 (b)). . The direction in which the tool gripper (2A) holding the current tool (T) moves away from the tool attachment / detachment position after a predetermined time has elapsed after the spindle (1) starts moving backward, that is, FIG. 1 (a) counterclockwise The main shaft (1) is moved along the trajectory (W) in the direction (see arrow a in FIG. 1 (a)), and the positional relationship in the Z-axis direction with respect to the main shaft (1) of the tool (T) is shown in FIG. When the tool change arm (2) is rotated counterclockwise as shown in Fig. 1 (a), the gripper (4A) of the tool gripper (2A) moves away from the tool removal position on the track (W). Move with. In FIG. 2, the relative positional relationship between the tool (T) and the main shaft (1) in the Z-axis direction is shown as the tool (2) moving in the Z-axis direction for convenience. Actually, the spindle (1) moves. When the grip portion (4A) of the tool gripper (2A) moves on the track (W), the spindle (1) moves along the track (W) together with the grip portion (4A) of the tool gripper (2A). The position of the tool (T) relative to the spindle (1) when the spindle (1) moves along the track (W) to a position (see the chain line u in Fig. 1 (a)) that is a predetermined distance away from the tool attachment / detachment position. 2 is shown by chain lines e and g in FIG. 2, and the main shaft (1) and the tool (T) do not interfere in the Z-axis direction.
[0023]
After the spindle (1) reaches the position indicated by the chain line u in FIG. 1 (a), it moves in the opposite direction (clockwise in FIG. 1 (a)) toward the tool detachment position along the track (W). (See arrow b in FIG. 1 (a)). While the main shaft (1) is moving and the tool arm (2) is rotating, the main shaft (1) is moved straight back to the tool removal position, and the extraction of the tool (T) from the main shaft (1) is completed. (Refer to chain line f in FIG. 2). The straight movement of the spindle (1) to the rear is stopped at the tool removal position.
[0024]
Thereafter, the movement of the spindle (1) along the track (W) and the rotation of the tool changing arm (2) are continued. As the tool change arm (2) rotates, the gripping part (4B) of the gripper (2B) that grips the next tool (T) moves on the track (W) to the tool removal position. When the spindle (1) starts moving in the direction away from the tool attachment / detachment position (clockwise in Fig. 1 (a)) after passing the tool attachment / detachment position along the track (W), the specified time passes. Then, the spindle (1) is moved straight forward so as to approach the tool changing arm (2). After a predetermined time has elapsed after the spindle (1) starts to move straight forward, before the gripping part (4B) of the tool gripper (2B) gripping the next tool (T) reaches the tool removal position. The main shaft (1) moves along the track (W) to a position away from the tool attachment / detachment position by a predetermined distance (see the chain line v in FIG. 1 (a)), and here, the main shaft (1) follows the track (W) of the main shaft (1). Stop moving. When the gripper (4B) of the tool gripper (2B) reaches a position corresponding to the spindle (1) where movement along the track (W) is stopped, the spindle (1) is moved to the tool gripper (2B). Together with the gripping part (4B), it is moved again along the track (W) toward the tool detachment position (see arrow c in FIG. 1 (a)). Then, the insertion of the tool (T) into the main shaft (1) is started during the movement of the grip portion (4B) of the tool gripper (2B) and the movement of the main shaft (1) along the track (W). After the movement of the tool gripper (2B) on the track (W) of the grip portion (4B) and the movement of the spindle (1) along the track (W) is stopped, the spindle (1) moves straight forward. If the operation is continued, the insertion of the next tool (T) into the spindle (1) is completed. When the tool (T) is inserted into the main shaft (1), the relative positional relationship between the two changes in a state opposite to that of the drawing shown in FIG. Thus, the tool (T) is exchanged.
[0025]
In the above embodiment, only the main shaft (1) moves in the front-rear direction, and the main shaft (1) and the tool change arm (2) approach and separate in the Z-axis direction. 2) or both of them may move in the front-rear direction so that the main shaft (1) and the tool change arm (2) approach and separate in the Z-axis direction. In addition, tool exchange between the spindle (1) and the tool magazine is performed in the same manner as described above.
[0026]
In the above embodiment, depending on the rotational speed of the tool changing arm or tool magazine and the moving speed of the main shaft in each direction, the main shaft can be moved only in two directions, the Z-axis direction and the X-axis direction.
[Brief description of the drawings]
1A and 1B show a state in which a tool gripper of a spindle and a tool arm is in a tool detaching position, and a tool attached to the spindle is gripped by a gripping portion of the tool gripper, (a) is a front view, and (b) is a side view. FIG.
FIG. 2 is a diagram showing a relative positional relationship between the two when the tool is pulled out from the spindle.
FIG. 3 is a time chart of tool change, (a) shows a conventional method, and (b) shows a method of the present invention.
[Explanation of symbols]
(1): Spindle
(2): Tool change arm
(2A) (2B): Tool gripper
(4A) (4B): Tool gripping part
(T): Tool
(W): Orbit

Claims (4)

A spindle that is rotatably supported by a spindle head that is movable in at least one of an X-axis direction and a Y-axis direction orthogonal to the Z-axis direction that is the spindle axis direction, and a tool that moves on a predetermined track A tool is exchanged with a tool gripping means having a portion and capable of approaching and separating in the Z-axis direction relative to the spindle, and when the tool is pulled out of the spindle, the tool gripper The tool and the tool gripping means are moved relative to each other along the trajectory in which the tool gripping part that grips the tool moves away from the tool attachment / detachment position while moving the spindle together with the tool gripping part. A tool changing method characterized in that the tool is pulled out from the main shaft by being separated in the Z-axis direction. A spindle that is rotatably supported by a spindle head that is movable in at least one of an X-axis direction and a Y-axis direction orthogonal to the Z-axis direction that is the spindle axis direction, and a tool that moves on a predetermined track A tool for exchanging a tool with a tool gripping means having a portion and capable of approaching and separating in the Z-axis direction relative to the spindle, and a tool to be attached to the spindle when the tool is attached to the spindle By moving the spindle along with the tool gripping part along the trajectory that moves so that the tool gripping part that grips the tool approaches the tool detachment position, the spindle and the tool gripping means are moved closer to each other in the Z-axis direction. A tool changing method characterized by inserting a tool into a spindle. The tool changing method according to claim 1 or 2, wherein the tool gripping means is a tool changing arm provided rotatably around an axis parallel to the Z-axis direction and having a tool gripper. The tool changing method according to claim 1 or 2, wherein the tool holding means is a tool magazine having a plurality of tool holding portions.

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