JP2000024862A - Dividing mechanism for automatic tool changer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform positioning accurately by reducing the axial clearance of a tool changing arm. SOLUTION: This dividing mechanism 1 changes a tool holder for holding a tool to be changed, by a tool changing arm 45, and divides the tool changing arm 45 by cam mechanism 2. In this case, stopper mechanism 3 is provided at the rear part of a shaft 46 integral with the tool changing arm 45, and positioning and impact absorption of the tool changing arm 45 are performed by this stopper mechanism 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an indexing mechanism for an automatic tool changer. More specifically, the present invention provides:
The present invention relates to an improvement in positioning means for a tool changing arm that moves back and forth at the time of tool changing.

[0002]

2. Description of the Related Art As shown in FIG. 7, an automatic tool changer 101 is provided to exchange a tool 104 between a tool stocker 102 and a spindle 103. When performing tool change, first, the tool holder 106 chucked by the tool change arm 105 is
After being unclamped and pushed forward by a cylinder (not shown) provided inside the spindle 103,
The tool is completely pulled out and replaced by the operation of the tool changing arm 105.

In this automatic tool changing apparatus 101, an indexing mechanism 10 for moving a tool changing arm 105 back and forth at a constant stroke and reciprocating between predetermined positions.
For example, a parallel cam, a roller gear cam for high-speed use, an NC servomotor, and the like are generally used. For example, the apparatus shown in FIG. 8 is a combination of a cam 108, two levers 109 and 110, and a link 111, and finally converts the rotational motion of the cam 108 into a linear motion, Arm 105 is moved back and forth.

At this time, as shown in FIG.
In some cases, the shape of 10 is asymmetric, the length of the arm is changed, and the swing width of the swing motion of the first lever 109 is enlarged to move the tool changing arm 105 back and forth. In this way, the tool changing arm 105 can be moved back and forth at a desired stroke without using a large cam.

[0005]

However, when the tool changing arm 105 is moved back and forth by increasing the swing width by the cam 108 as described above, the clearance of the levers 109 and 110 is also enlarged and the tool changing arm 105 is extended. 10
5 may be transmitted. That is, in the cam 108 used for indexing the tool changing arm 105, the clearance between the cam groove 113 and the cam follower 114 is the clearance (play, play,
Therefore, depending on the length ratio of each element such as the lever 109 connected to the cam groove 113, the clearance may be enlarged.

When the tool changing arm 105 rattles largely in the axial direction in this way, a shift may occur particularly at a predetermined position with the tool holder 106, and a loud noise may be generated. Therefore, in order to reduce such a noise, it is preferable that the positioning be more accurate at a predetermined position, particularly at a position where the tool holder 106 is gripped or separated.

In addition, the automatic tool changer 101 is reduced in size.
If the speed is to be increased, the tool
The distance to the position 4 needs to be reduced. Therefore, when the tool changing arm 105 is shortened, the center shaft 11
2 and the axis of the cam 108 are closer, and the shape of the cam 108 must be smaller. Therefore, in order to secure a stroke for pulling out the tool holder 106 from the spindle 103, the lift amount of the cam 108 and the lever 1
For example, the ratio of the length to 09 or the like must be increased. Therefore, the gap of the cam follower 114 that transmits the movement to the lever 109 in the cam groove 113 is also enlarged,
Clearance increases. Also, since these elements must be stored in a small space, lever 1
It is necessary to devise the number and arrangement of 09, etc., and the clearance in each element may be a clearance of the tool changing arm 105 which is larger.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an indexing mechanism for an automatic tool changer which can accurately perform positioning by reducing the axial clearance of a tool changing arm.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, a tool holder holding a tool to be replaced is replaced by a tool replacement arm and a tool replacement arm is provided. In the indexing mechanism of the automatic tool changer, the index is determined by a cam mechanism. I'm trying to do it.

Therefore, when the tool changing arm is at a predetermined position, particularly at a position where the tool holder is gripped or separated, the rattling is reduced, and accurate positioning is achieved. As a result, the operation of the tool changing arm, such as when gripping the tool holder, becomes accurate, and the impact noise is reduced. In addition, the wear of the contact portion is reduced, so that the tool changing arm, such as the chuck portion of the tool changing arm, is reduced. Long life.

In the indexing mechanism of the automatic tool changer according to the second aspect of the present invention, the cam mechanism has two cam portions, and performs forward and backward movement and turning of the tool changing arm. In this case, the tool changing arm is moved back and forth as predetermined by the movement of the cam mechanism in the indexing mechanism,
In addition, since the tool can be swirled, the tool can be automatically changed using the tool changing device.

In the indexing mechanism of the automatic tool changer according to the third aspect of the present invention, the stopper mechanism has a stopper pin, a disc spring, and a screw member for adjusting a buffer stroke. According to this stopper mechanism, the elastic force of the disc spring can be transmitted to the tool changing arm via the stopper pin and urged to perform positioning and shock absorption. If a screw member is used, the position of the stopper pin can be changed, and the buffer stroke can be easily changed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail based on an example of an embodiment shown in the drawings.

1 to 6 show an embodiment of an indexing mechanism of the automatic tool changer according to the present invention. The automatic tool changing device 50 uses a tool changing arm 45 to change tools between a tool stocker and a spindle. At the time of this tool change, a mechanism for moving the tool changing arm 45 back and forth is the indexing mechanism 1 as illustrated. In the indexing mechanism 1 of the present invention, the stopper mechanism 3 is provided at the rear of the central shaft 46, which is a shaft, to absorb the impact when the tool changing arm 45 moves back and forth, and to perform positioning.

The indexing mechanism 1 in the present embodiment is shown in FIGS.
As shown in FIG. 3, the cam 45, the first lever 53, the link 54, the second lever 55, the cam follower 67, etc.
It is provided so as to be moved back and forth and positioned at a predetermined position. Further, in the automatic tool changer 50, the roller gear cam 56 and the cam followers 71,.
Movement of the tool changing arm 45 to the central axis 46.
It is provided so that it can be turned around.

The tool changing arm 45 is rotated by a bearing 59 provided on a frame 58 and a bearing 60 provided inside so that a center shaft 46 as a center of rotation can slide in the axial direction. Supported as possible. The forward and backward strokes of the tool changing arm 45 are appropriately set according to the swing width of the swing of the second lever 55.

The cam 51 forms the timing of the forward and backward movement of the tool changing arm 45, and is provided with a cam surface 52 having a groove having a shape as shown in FIGS. A projection 61 provided at one end of the first lever 53 is engaged with the cam surface 52, and the distance from the center 62 of the cam 51 is changed according to the rotation of the cam 51. Therefore, when the cam 51 rotates, the projection 61 swings and swings the first lever 53 around the swing center 63.

As shown in FIGS. 1 and 2, the first lever 53 is rotatably attached to a swing center 63 provided on a frame 58, and the second lever 55 is rotatably attached to a swing center 64. A link 54 is rotatably provided between a fulcrum 65 at an end of the first lever 53 and a fulcrum 66 at an end of the second lever 55, and the swinging motion of the first lever 53 is applied to the second lever 55. Has communicated. In this case, the shapes of the first lever 53 and the second lever 55 are
The ends of the second and third levers are formed so that a large swing width can be finally obtained at the end of the second lever 55.

A rotary shaft 69 to which the above-mentioned cam 51 and the like are attached is provided inside the automatic tool changer 50. The rotating shaft 69 is provided in a direction perpendicular to the paper surface as shown in FIG.
Are oriented in a direction different from the longitudinal direction. In FIG. 2, the rotation shaft 69 is represented only by its center line 69c. In addition, although not particularly shown in the figure, FIG.
A drive source for rotating the rotation shaft 69 is provided inside a portion indicated by reference numeral 70 in FIG.

The roller gear cam 56 is attached to the rotating shaft 69. As shown in FIG. 3, the roller gear cam 56 is provided on the rear side of the cam 51 and coaxially with the cam 51 to form the cam portion 7. This figure 3
As can be seen from FIG.
And a cylindrical cam follower 7 radially provided about the central axis 46.
1, ..., 71 are engaged. In this embodiment, the roller gear cam 56 is provided separately from the cam 51. However, it goes without saying that the roller gear cam 56 may be provided integrally as a composite cam as shown in FIG. Around this roller gear cam 56, cam followers 71,
, 71 are formed diagonally with grooves 72.

The cam follower 71 transmits the rotation of the rotary shaft 69 to the central shaft 46, and is fixed to the central shaft 46 as shown in FIG. Since the cam follower 71 in this embodiment has a cylindrical shape, the groove 7
Although it is possible to realize a smooth engagement with 2, the shape is not particularly limited to this.

Then, the automatic tool changer 50 of the present embodiment
Is further provided with a stopper mechanism 3. The stopper mechanism 3 is provided with a stopper pin 4, a disc spring 5, and a screw member 6 at a rear position of the center shaft 46 as shown in FIG. Is absorbed and positioned.

As shown, the stopper pin 4 is provided so as to be movable back and forth in the axial direction with its center coincident with the axis of the central shaft 46. A disc spring 5 is provided around the stopper pin 4, and urges the head 4 a of the stopper pin 4 toward the front side of the device 50. Therefore, while the head 4a of the stopper pin 4 is in contact with the end face of the central shaft 46, the central shaft 46 is receiving a forward urging force. The disc spring 5 is an example of a means for applying an urging force to the stopper pin 4 and is not particularly limited to this. However, when the installation space is limited and a relatively large accumulating force is provided, This is one of the preferred means.

The stopper pin 4 is provided so that an end 4b facing the rear side projects from the end frame 8, and the end 4b is further threaded. A screw member 6 is attached to the screw and abuts against the end frame 8 to regulate the stroke width of the stopper pin 4. In the case of the present embodiment, the screw member 6 is constituted by two nuts, and the easy adjustment of the stroke width and the prevention of loosening at times other than the adjustment are achieved.

The center shaft 46 and the tool changing arm 45
1 is in the rearward position as shown in FIG. 1, the stopper pin 4 is in contact with and biases the central shaft 46, but the central shaft 46 is in the forward position (the cam follower in FIG. 1). 67 is moved to the position indicated by the imaginary line), that is, the stopper pin 4 is
It does not matter whether or not it is in contact with the end face. If there is no contact, the central axis 46
Is no longer biased in the forward position, but at this time, the tool changing arm 45 also moves forward, and fine positioning in the axial direction such as when gripping a tool is not required. There is no particular problem even if it is not energized.

Next, the relationship between the shape of the cam surface 52 and the movement of the tool changing arm 45 will be described.

The cam 51 of the cam mechanism 2 in the present embodiment
Has a mechanism for moving the tool changing arm 45 forward at a speed substantially equal to the speed at which the tool holder is pushed out by a cylinder (not shown) of the spindle driving device. Is moved back and forth in two stages, a stage of pushing out in synchronism with the pushing speed of the cylinder, and a stage of pushing out for the original forward and backward movement.

In order to realize such two-stage forward and backward movement, the cam surface 52 in the present embodiment is formed in a shape as shown in FIG. The state of forward and backward movement of the tool changing arm 45 when the cam 51 having such a shape makes one rotation, for example, clockwise will be described below with reference to the graph shown in FIG. Here, the state shown by the solid line in FIG. 4 is the rotation angle of 0 °.

First, in the range of R1 in FIG.
Is an arc shape. Therefore, even if the cam 51 rotates within the range of R1, the projection 61 of the first lever does not move, and the tool changing arm 45 does not move (corresponding to R1 in FIG. 6). The tool changing arm 45 does not move back and forth in this way, but pivots clockwise from a rotation angle of 10 ° to 65 °.

When the cam 51 further rotates, the projection 61 reaches the area R2 of the cam surface 52. The cam surface 52 at this R2 has a shape that slightly increases the diameter from the center 62, and as shown in FIG.
The projection 61 is moved to 5 ° so that the tool changing arm 45 slides smoothly. The speed at this time is substantially the same as the pushing speed of the tool holder by the cylinder, and the sliding width thereof is also substantially equal to the pushing width of the tool holder by the cylinder. And the rotation angle 72.
Since the cam surface 52 from 5 ° to 80 ° is again arcuate, the tool changing arm 45 stops sliding again in the range of R3 as shown in FIG. Therefore, it is possible to eliminate the inertia accompanying the sliding of the tool changing arm 45.

The rotation angle is in the range of R4 from 80 ° to 150 °, where the protrusion 61 moves, and the first
The lever 53 also swings greatly. Therefore, the tool changing arm 45 also slides largely forward and projects from the device 50 (R4 in FIG. 4). Also on the way,
The tool changing arm 45 starts to rotate clockwise again.
And since the movement of the projection 61 stops at the arc-shaped R5,
The tool changing arm 45 stops in that state.

At R6 from a turning angle of 210 ° to 280 °, the diameter of the cam surface 52 gradually decreases. Therefore, the projection 61 moves in the opposite direction to the above, and starts sliding the tool changing arm 45 backward. The clockwise turning of the tool changing arm 45 is stopped during the backward sliding. Then, in R7, the sliding stops once, similarly to R3, and slides backward again in the range of R8. This R
The sliding speed at 8 is the same as that at R2. When the cam 51 further rotates, it returns to the state of R1 again.

As described above, in this embodiment in which the cam surface 52 is formed as shown in FIG. 4, a tool changing arm such as R2 and R4 when sliding forward, and R6 and R8 when sliding backward. The speed of the forward sliding and the backward sliding of the 45 is divided into two stages. As a result, in the range of R2, that is, in the first movement stage, the sliding speed can be synchronized with the pushing speed of the tool holder.

Further, since the stopper mechanism 3 provided in the indexing mechanism 1 of the present invention acts on the tool changing arm 45 and the center shaft 46 which perform the forward and backward movement and the turning movement as described above, the equipment is operated as follows. The accuracy is improved. That is, when the center shaft 46 is retracted, the stopper pin 4 abuts on the center shaft 46 and urges forward, so that the tool changing arm 45 does not rattle at each position and is positioned at the desired position. Become. Therefore, the backlash of the tool changing arm 45 can be eliminated particularly at the rear position where fine positioning in the axial direction is required. For this reason, even if the tool exchange arm 45 is caused to collide with the tool holder while rotating at a high speed, the misalignment of the center is small, and the wear at this time is also reduced.

As a result, it is less necessary to increase the processing accuracy of the grooves and the like in the cam mechanism 2 of the indexing mechanism 1. Therefore, the cost in processing can be reduced.

The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited thereto, and various modifications can be made without departing from the gist of the present invention. For example, the stopper mechanism 3 shown in this embodiment is merely an example, and such a stopper pin 4
In addition to the combination of the stopper mechanism 5 and the disc spring 5, a biasing means such as various compression coil springs and hydraulic dampers can be used alone or in combination with a pin having another shape as the stopper mechanism 3.

The timing of the forward and backward movement and turning of the tool changing arm 45 described with reference to FIG. 6 is merely an example, and can be appropriately set according to the equipment.

[0038]

As is apparent from the above description, according to the indexing mechanism of the automatic tool changer according to the first aspect of the present invention, accurate positioning and impact absorption of the tool changing arm can be performed. The impact sound can be reduced by accurately grasping the holder. Therefore, a faster and more reliable tool change becomes possible. In this case, the wear of the contact portion is reduced, so that the life of the chuck portion and the like can be extended.

Further, according to the stopper mechanism of the present invention, the rattling of the tool changing arm can be absorbed, so that it is possible to eliminate the occurrence of rattling accompanying the downsizing of the automatic tool changing device. Moreover, since the stopper mechanism has a relatively simple structure, the above-described effects can be obtained at a low cost.

Further, in the indexing mechanism of the automatic tool changer according to the second aspect of the present invention, since the tool changing arm is moved back and forth and turned by the two cam portions, the arm is represented by a cam diagram. It can make a certain predetermined movement. Moreover, since no rattling occurs at the predetermined position,
The tool can be changed accurately and automatically.

According to the indexing mechanism of the automatic tool changer according to the third aspect of the present invention, the tool changing arm is urged with a large load capacity for relatively simple structure to perform positioning and shock absorption. be able to. If a screw member is used, the buffer stroke can be easily adjusted.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view from the front of an automatic tool changer for illustrating an indexing mechanism of the automatic tool changer of the present invention.

FIG. 2 is a plan view showing a cross section of the automatic tool changer of FIG.

FIG. 3 is a vertical sectional view taken along a line III-III in FIG. 1 from the right side.

FIG. 4 is a simplified view showing a cam surface of a cam and movements of each lever, link, and cam follower.

FIG. 5 is a diagram showing an example of a composite cam including a cam and a roller gear cam.

FIG. 6 is a graph showing an example of timing of forward and backward movement and turning of a tool changing arm.

FIG. 7 is a schematic view showing the entirety of a conventional automatic tool changer.

FIG. 8 is a longitudinal sectional view showing a conventional spindle drive device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Indexing mechanism 2 Cam mechanism 3 Stopper mechanism 4 Stopper pin 5 Disc spring 6 Screw member 7 Cam part 45 Tool changing arm 46 Center axis (shaft) 50 Automatic tool changing device

Claims (3)

[Claims] 1. An indexing mechanism for an automatic tool changing apparatus, wherein a tool holder holding a tool to be changed is changed by a tool changing arm and the tool changing arm is indexed by a cam mechanism. An indexing mechanism for an automatic tool changer, wherein a stopper mechanism is provided at a rear portion of a shaft integrated with the tool changing arm, and the stopper mechanism performs positioning and shock absorption of the tool changing arm. 2. An indexing mechanism for an automatic tool changer according to claim 1, wherein said cam mechanism has two cam portions, and performs forward and backward movement and turning of said tool changing arm. 3. The indexing mechanism according to claim 1, wherein said stopper mechanism includes a stopper pin, a disc spring, and a screw member for adjusting a buffer stroke.