JPS5824220B2 - Machine tool tool change mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tool exchange mechanism for a machine tool, and particularly to a tool exchange mechanism that exchanges tools between a turret holding a large number of tools and a spindle according to the movement of a spindle head. By configuring the turret to move close to the spindle, interference between the tool held in the turret and the workpiece during machining can be prevented, and the number of tools held by the turret can be increased, making it easier for the machine tool to operate. This invention relates to a tool changing mechanism that has been improved to improve machining capacity.

Conventionally, in the tool exchange mechanism of machine tools, a tool turret or tool magazine holding multiple tools at equal pitches is rotatably attached to a position close to the spindle on the spindle head, and the spindle head is moved when changing tools. Tool changing mechanisms of the type are known in which indexing rotation of a tool turret and tool loading/unloading are activated in response.

In this well-known type of tool change mechanism, the tool turret is composed of a tool holder and a disk rotatably fitted into the tool holder, and the spindle head is moved via a link mechanism provided between the rotating disk and the spindle head. The rotary disk is indexed and rotated for each pitch angle in accordance with the pitch angle, and tools are exchanged between the turret and the main shaft.

In this case, the tool holding turret is always held close to the spindle not only when changing tools, but also during machining with the machine tool. Therefore, during machining, the tool attached to the spindle is held in the tool holding hole of the tool turret. A configuration is adopted in which the cutting rotation is performed while being held.

The known tool changing mechanisms of the type described above have the advantage of being relatively simple in construction and accurately accomplishing tool changing operations, but on the other hand, the tool turret is always located in close proximity to the spindle, so that the tool is not easily removed during machining. The turret may approach the workpiece and the workpiece may interfere with the turret or a tool held in the turret that is not in use.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a tool changing mechanism for a machine tool which, while following the advantages of the known types of tool changing mechanisms mentioned above, is further improved.

That is, according to the present invention, in a tool exchange mechanism for a machine tool that exchanges tools between the spindle and a turret that holds a plurality of tools at equal pitches in accordance with the movement of the spindle head of the machine tool, the spindle head The turret is pivotally coupled to a sliding member provided so as to be relatively slidable in the direction of movement of the spindle head via a swing support arm, and the turret is moved in the direction of the spindle head side with respect to the tool exchange position near the spindle. When the spindle head and the turret move in translation to a certain position above the machining position, A fixedly disposed stopper is provided which abuts and engages with the pivoting support arm of the turret to restrain the turret, and then a pivoting force acting from the stopper causes the turret to be rotated while only the spindle head continues upward movement. The tool is rotated from the tool holding position to the tool exchange position against a spring biasing force, and an index rotation mechanism is provided between the turret and the spindle head when the tool exchange position is reached, and the spindle head is further moved upward. The tool is characterized in that the indexing rotation mechanism is operated in the meantime, and the turret is indexed and rotated by a pitch angle, thereby sequentially indexing each tool to the tool exchange position.

Hereinafter, the present invention will be described in detail based on embodiments shown in the attached circular.

FIG. 1 is a schematic side view showing an example of the main body of a machine tool equipped with a tool changing mechanism according to the present invention.

In Figure 1, the main body of the machine is a column 10 and a bed 1.
2, and a work table 14 on the bed 12.
is included.

This work table 14 is connected to the bed 12 in an X-axis direction perpendicular to the paper surface of FIG.
They are each configured to be moved in the axial direction by a drive motor (not shown) such as a servo motor.

The upper surface of the work table 14 is formed as a table surface on which a workpiece can be fixedly placed.

A spindle head 16 is provided above the work table 14, and a ball spline groove formed inside the bracket 22 of the spindle head 16 is fitted into a ball spline shaft 24 fixed to the column 10. By aligning them together, they can be moved in the Z-axis direction by a drive motor (not shown) such as a servo motor.

A spindle 18 is mounted inside the spindle head 16 to rotate under the driving force of a spindle rotation motor (not shown), and a tool 30a is fitted to the tip of the spindle 18 via a tool arbor 30. It is formed to be worn.

Now, 20 shows a tool exchange mechanism according to the present invention, and this tool exchange mechanism 20 has a tool turret 26, and the tool turret 26 has a large number of tool holding holes 28 at equal pitches on its outer circumferential surface. A large number of tools 30 are placed in this tool holding hole 28.
a is inserted and held through the tool arbor 30.

The tool turret 26 is formed as an annular body supported at the tip of a swing arm 42 attached by a pivot pin 44 to a sliding plate 40 that is slidable in the Z-axis direction on the side surface of the spindle head 16. It is configured to be indexable and rotatable therearound by a structure to be described later, and to be pivotable together with the pivot arm 42 in both directions indicated by the arrow P with respect to the pivot pin 44.

Further, the swing arm 42 has a spring 36 whose one end is locked to the upper end of a vertical bracket 34 fixed to the side surface of the spindle head 16.
The other end is locked, and by receiving the biasing force of the spring 36 in the spring direction, the swing arm 42 supporting the tool turret 26 is normally maintained in the horizontal state shown in FIG.

Reference numeral 32a denotes a stopper member that abuts and engages with the swinging arm 42 during the tool exchange operation described later to start the swinging operation of the tool turret 26, and its upper end is connected to the tip of the bracket 46 fixed to the upper end of the column 10. is fixed to.

Further, 32b is another stopper member that defines the amount of rotation of the rotating arm 42 from the horizontal state, and this stopper member 32b
The tool turret 26 of the tool change mechanism 20 comes closest to the main shaft 18 when the swing arm 42 comes into contact with the tool turret 26 .
Tool exchange can be achieved between one of the many held tools 30a and the tool 30a mounted on the spindle 18, as will be described later.

Therefore, in the following, the position where the tool turret 26 is located away from the immediate position of the main shaft 18 shown in FIG. The position where the tool turret 26 reaches the closest position to the main spindle 18 through the rotation of the tool 42 will be referred to as the "tool change position", and the structure, operation, and effects of the tool change mechanism 20 according to the present invention will be further explained with reference to specific examples. do.

FIG. 2 is an enlarged partial side view, partially in section, of a first embodiment of a tool changing mechanism 20 according to the invention, in which elements already described in FIG. 1 are designated by the same reference numerals. .

As shown in FIG. 2, the slide plate 40 is attached to be slidable in the Z-axis direction along two Z-axis guide rails 52a fixed to the side surface of the spindle head 16, and the upper limit of its sliding is It is defined by a stop plate 52b fixed to the spindle head 16.

The swing arm 42 is held in the horizontal state shown in the figure under the spring force of the spring 36, and the slide plate 40 is in contact with the stop plate 52b when the tool turret 26 is held at the tool holding position.

In this way, when the tool turret 26 of the tool change mechanism 20 is in the tool holding position, if the spindle head 16 moves downward along the ball spline shaft 24 by the drive of the two-axis drive motor, the tool turret 26 also moves to the stop plate 52b. and moves downward through engagement with the sliding plate 40.

When the tool 30a attached to the spindle 18 via the tool arbor 30 reaches the workpiece held on the work table 14 shown in FIG. 1, the spindle rotation drive motor rotates the spindle 18. Machine processing can be performed on the workpiece.

In this case, according to the present invention, the tool turret 26 of the tool change mechanism 20 is retracted to the tool holding position, so that the tool turret 26 or the tool held by the tool turret 26 may come into contact with the workpiece during machining. The fear of interference is successfully avoided.

In other words, in the conventional tool change mechanism, the tool turret is held close to the spindle during machining, so the tool turret itself or the tip of the tool held by the tool turret and protruding outward changes to the workpiece as machining progresses. Although contact interference may occur with the workpiece on the table, in the case of the tool change mechanism according to the present invention, as described above, the tool turret 26 is retracted to the tool holding position far from the position closest to the spindle, so contact interference occurs. The occurrence of this can be avoided.

In particular, since it has become possible to avoid contact interference between the protruding tip of the tool held in the tool turret 26 and the workpiece, the pitch interval between adjacent tool holding holes 28 in the tool turret 26 can be made as narrow as possible. Therefore, it is possible to increase the number of tools held by the conventional tool changing mechanism, and therefore, a machine tool equipped with the tool changing mechanism according to the present invention can also achieve improved machining performance.

To achieve the tool changing function in the embodiment of FIG. 2, the spindle head 16 is first moved upwardly along the ball spline shaft 24 by being driven by a two-axis drive motor.

At this time, the tool turret 26 of the tool change mechanism 20 also
Since it is always subjected to an upward pulling force by the spring biasing force 6, it is translated to the spindle head 16 and moves upward in the Z-axis direction.

When the swing arm 42 eventually comes into contact with the lower end of the stopper member 32a whose length has been adjusted appropriately, the upward movement of the swing arm 42 and the tool turret 26 is blocked.

In this state, the spindle head 16 is attached to the ball spline shaft 24.
As the pivot arm 42 continues to move along the pivot pin 44
Since the tool turret 26 pivots around , the tool turret 26 pivots from the tool holding position toward the tool exchange position nearest to the main spindle 18.

When the tool turret 26 moves to the tool exchange position and the swing arm 42 comes into contact with the stopper member 32b, the pinion 54, which is rotatably attached to the swing arm 42 in this embodiment, is attached to the lower end of the spindle head 16. rack 50
It is formed to mesh with the

Therefore, when the spindle head 16 is further moved to the Z-axis upward force from the state in which the pinion 54 and the rack 50 are engaged, the tool turret 26 is moved so that its swing arm 42 is connected to the upper and lower stopper members 32.
The pinion 54 is rotated by the rack 50 which rises together with the spindle head 16 since it is clamped and restrained by the pinion a and 32b.

Therefore, a bevel gear 56 provided concentrically with this pinion 54
The wheel 5 is rotated and meshed with the bevel gear 56.
8, the tool turret 26 is turned in one direction and rotated around its central axis.

As a result, the tool turret 26 indexes and rotates at the tool exchange position closest to the main spindle 18.

Of course, in this case, the amount of meshing between the rack 50 and the pinion 54 and the meshing rotation ratio between the bevel gear 56 and the wheel 58 are such that indexing rotation of the tool turret 26 by one pitch angle is achieved in advance by one tool change operation. Designed and formed.

The tool turret 26 is also equipped with a wheel 5 so that the tool turret 26 is always indexed and rotated in one direction to achieve tool exchange between the tool turret 26 and the spindle 18 in a predetermined order.
A ratchet wheel 60 is attached integrally with the tool turret 8, and a ratchet 62, which is also fixed to the inner bottom surface of the tool turret 26, meshes with this ratchet wheel 60, and the ratchet wheel 60 and ratchet 62 prevent the tool turret 26 from reversing. is forming.

Since the tool turret 260 indexing rotation mechanism is formed as described above, when the turret 26 reaches the tool exchange position, the spindle head 16 is continuously moved upward and the tool 30a mounted on the spindle 18 is removed. The tool arbor 3
0 and released from the main shaft 18 and returned to the empty tool holding hole 28 of the tool turret 26. Thereafter, the tool turret 26 is indexed and rotated by one pitch angle as described above, and the next tool 30a and its tool arbor 30 are removed. This makes it possible for the main shaft 18 to come directly under the main shaft 18.

When this state is reached, if the spindle head 16 is then moved downward in two axial directions, the spindle 18 will grip the indexed new tool 30a, and the tool will be further moved in accordance with the downward movement of the spindle head 16. The tool turret 26 of the exchange mechanism 20 returns from the above-described tool exchange position to the tool holding position together with the rotation arm 42, thereby completing the tool exchange.

In addition, in FIG. 2, the adjustment screw 32'b provided on the stopper member 32b finely aligns the axis of the tool holding hole 28 with the axis of the main shaft 18 when the tool turret 26 reaches the tool exchange position. The rotation movement of the tool turret 26 is restrained with the two axes accurately aligned.

Figures 3a''-e are schematic diagrams sequentially showing the relative positional relationship between the spindle head 16 and the tool turret 26 during the tool changing action in the tool changing mechanism of the embodiment shown in Figure 2. 3a is the state before the start of tool exchange, and FIG. 3 is a state in which the tool turret 26 has rotated to the tool exchange position and the tool 30a of the spindle 18 is placed in the empty tool holding hole 28 in its tool arbor 30.
3C is a state where the tool 30a is returned from the main shaft 18 to the tool turret 26, FIG. 3D is a state where the tool turret 26 is being indexed and rotated, and FIG. Each figure shows a state in which a new tool 30a is fastened to the main spindle 18 via its tool arbor 30 due to the downward movement of the spindle head 16.

FIG. 4 is a partially enlarged sectional view including a partial sectional view showing a second embodiment of the tool changing mechanism according to the present invention, and shows the elements shown in FIG. 1 or the embodiment shown in FIG. 2. Similar components are designated by the same reference numerals.

As is clear from the illustration in the embodiment shown in FIG. 4, the structure and operation for pivoting the tool turret 26 of the tool changing mechanism 20 from the tool holding position to the tool changing position during tool changing are the same as those shown in FIG. This embodiment has exactly the same structure as the first embodiment of the present invention shown in FIG.

However, in the second embodiment, the indexing and rotation mechanism for the tool turret 26 is constructed using a link transmission mechanism 70, which is completely different from the gear mechanism used in the first embodiment.

Therefore, a tool turret 260 indexing and rotating mechanism using this link transmission mechanism 70 will be described below.

Now, the link transmission mechanism 70 is a universal joint between the upper outer part of the ratchet wheel 60 and the link rod 74).
The first link rod 74 and the second link rod 76 are connected by a universal joint 72a, and the second link rod 76 and the bracket 90 attached to the spindle head 16 are connected by a universal joint 72a. They are formed by being joined by a ball joint 84 fitted into a joint hole 94.

The second link rod 76 is inserted through the ball joint 84, and the ball joint 84 can be freely moved within the ball surface hand hole 94 of the bracket 900.

A spring seat 78 is fixed to the lower part of the second link rod 76, and an elastic spring 80 is wound around the second link rod 16 between the spring seat 78 and the bottom surface of the tip of the bracket 90. It is installed.

Further, a stopper 82 is fixed to the upper end of the second link rod 76.

Note that the bracket 90 has a bolt 92 attached to the top of the spindle head 16.
It is fixed by an appropriate fixing means such as.

The link mechanism 70 configured as described above rotates the first and second link rods 74 as the tool turret 26 pivots from the tool holding position to the tool exchange position during tool exchange.
．． Both link rods 76 extend and move downward against the spring force caused by the extension of the telescopic spring 80, and when the tool turret 26 reaches the tool change position closest to the main spindle, the stopper 82 at the upper end of the second link rod 76 is moved downwardly by the stopper 82 of the bracket 90. It comes into contact with the upper surface and reaches a state where downward extension movement is no longer possible.

When this state is reached, when the spindle head 16 further rises along the ball spline shaft 24 due to the Z-axis force, the bracket 90
The first and second link rods 74, 76 are pulled upward through engagement with the stopper 82.

On the other hand, the tool turret 26 that has reached the tool exchange position is stopped by the stop member 32a as described above.

32b, the tool turret 26 is started to index and rotate in response to the lifting force acting on the first and second link rods 74, 76.

Even in the indexing rotation mechanism using this link transmission mechanism 70, the tool turret 26 always rotates only in a certain direction due to the engagement between the ratchet wheel 60 and the ratchet 62 provided on the tool turret 26, and tool exchange is always performed in a certain order. It is designed to be carried out according to the following.

Of course, in the link transmission mechanism described above, the lengths of the first and second link rods 74 and 76 are selected in advance so that one pitch of index rotation is performed in the tool turret 26 in one tool exchange operation. In addition, the connection point connecting the first link rod 74 to the ratchet wheel 60 attached to the tool turret 26 via the universal joint 72a is selected in advance at a position where accurate indexing rotation is activated. Needless to say.

Note that when the tool exchange is completed and the tool turret 26 is retracted from the tool exchange position to the tool holding position, the link transmission mechanism 70
The first and second link rods 74 and 76 are extended upwardly by the tensile force of the telescopic spring 80 to prepare for indexing rotation during the next tool change.

Although the present invention has been described above based on the first and second embodiments, the present invention is not limited to being installed in a vertical machine tool as in both of these embodiments, and is not limited to cases in which the main shaft is arranged in the horizontal direction. It can also be applied to horizontal machine tools without any special modification, and therefore, even in horizontal machine tools, contact interference between the tool change mechanism and the workpiece can be avoided, and the tool turret can accommodate a larger number of tools than before. By holding it, the machining ability of the machine tool can be improved.

Furthermore, unlike the conventional tool exchange mechanism, the tool exchange mechanism of the present invention is configured such that the machining tool is completely transferred from the tool turret to the spindle head side when the tool is exchanged. For example, it is possible to form a key groove in the tool mounting hole, while a key is preformed in the tool arbor to achieve the orientation of the tool when changing the tool. By configuring a keyed connection between the arbor and the spindle, slippage during torque transmission between the spindle and the tool is completely prevented, thus ensuring reliable cutting even when the cutting load is large during machining. It also has the advantage of being able to do this.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing the main body of a machine tool equipped with a tool changing mechanism according to the present invention, and FIG. 2 is a partial cross section showing a first embodiment of the tool changing mechanism for a machine tool according to the present invention. FIGS. 3a"'-e are schematic diagrams illustrating changes in the relative positional relationship between the tool turret and the spindle head during a tool change operation in the embodiment shown in FIG.
FIG. 4 is an enlarged partial side view including a partial sectional view showing a second embodiment of the tool changing mechanism for a machine tool according to the present invention. In the figure, 10... Column, 12... Bed, 14... Work table, 16...
・Spindle head, 18... Main spindle, 20... Tool exchange mechanism, 24... Ball spline shaft, 2
6... Tool turret, 28... Tool holding hole, 30... Tool arbor, 30a...
・Tools, 32a, 32b--stop member,
36... Spring, 40... Sliding plate, 4
2... Swivel arm, 44... Pivot pin.

Claims (1)

[Scope of Claims] 1. In a tool exchange mechanism for a machine tool that exchanges tools between the spindle and a turret that holds a plurality of tools at equal pitches according to the movement of the spindle head of the machine tool, The turret is pivotally connected to a sliding member provided so as to be relatively slidable in the direction of movement of the spindle head via a swing support arm, and the turret is moved toward the side of the spindle head with respect to the tool exchange position near the spindle. The tool is moved in translation together with the spindle head by spring-biased holding toward the tool holding position that was far away from the retracted position, and when the spindle head and the turret are translated to a fixed position above the machining position, the A fixed stop is provided which abuts and engages with a swing support arm of the turret to restrain the turret, and then a swing force acting from the stop causes the turret to be moved by a swing force acting from the stop while only the spindle head continues upward movement. A rotation operation is performed against a spring biasing force from the holding position to the tool exchange position, and an indexing rotation mechanism is provided between the turret and the spindle head when the tool exchange position is reached, while the spindle head is further moved upward. A tool changing mechanism for a machine tool, wherein each tool is sequentially indexed to the tool changing position by activating the indexing rotation mechanism and indexing and rotating the turret by a pitch angle. 2. In the tool changing mechanism for a machine tool as set forth in claim 1, the turret is attached to the sliding member so as to come into contact with the swing support arm when the turret reaches the tool changing position. A tool changing mechanism for a machine tool configured such that its rotational movement is restricted by a second stopper.