JP2535479B2 - Automatic tool changer - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to an automatic tool changer for use in CNC drill of a machine tool, especially when rotating people work for tool change turret for holding the tool, simultaneously CNC drill the turret Of the turret, the relative speed of the turret with respect to the main spindle is sufficiently reduced to remove the impact generated when the tool is exchanged, and the movement of the spindle head required for the tool exchange is performed. The present invention relates to an automatic tool changing device which shortens the distance, speeds up the tool changing operation, and downsizes the device.

[0002]

2. Description of the Related Art Recently, in the field of machine tools, machine tools equipped with an automatic tool changer, particularly so-called CNC drills, have been widely used. As shown in FIG. 9 , a tool changer used for such a CNC drill conventionally has a turret 74 which accommodates a plurality of tools on its circumference. When the tool replacement is instructed, first, orientation of the spindle on which the tool (holder) 70 is mounted is carried out, and then the spindle head 60 is moved upward. When the spindle head 60 moves upward, the cam 62 engages with the lever 64 and the lever 64 rotates. This rotational movement is transmitted to the crank 68 via a link 66 attached to the end of the lever 64,
Is rotated (hereinafter, the rotation of the crank and the turret is referred to as a swing operation), and a predetermined grip 72 disposed on the outer periphery of the turret 74 approaches the tool holder 70 mounted on the spindle. , Hold this. Then, in order to pull out the tool holder 70 from the spindle, the spindle head 60 further moves upward. When the tool holder 70 is removed from the main shaft, the turret 74 is indexed by the rotation of the main shaft while the spindle gear 76 and the turret gear 78 are engaged with each other, whereby the desired tool on the turret 74 is selected. It Then, the spindle head 60 moves downward to move the spindle gear 76 and the turret gear 78 of the spindle.
Is disengaged. During this time, orientation is carried out again in order to recover the orientation deviation due to the turret indexing operation. Then, when the spindle head 60 further moves downward, the tool holder held by the grip 72 is mounted on the spindle, and the tool exchanging operation is completed.

In the conventional automatic tool changer described above, when the grip 72 holds the tool holder 70 mounted on the spindle by the swing motion of the turret 74, or the tool holder gripped by the grip 72 serves as the spindle. When mounted, an impact occurs due to the swing motion of the turret 74. In order to suppress this impact as small as possible, the conventional automatic tool changer must reduce the feed rate of the vertical movement of the spindle head 60 in the section where the impact occurs, and therefore, due to the decrease in this feed rate, There is a drawback that the time required for the tool changing operation becomes long. In addition, in the conventional automatic tool changer, in order to pull out the tool holder from the spindle, after gripping the tool holder attached to the spindle, the spindle head 60 is removed until the tool holder is completely removed from the spindle. It must be further on the motion. On the contrary, when mounting the tool holder on the spindle, keep the spindle head until the tool holder is completely mounted on the spindle.
It must be downward movement. For this reason, in the conventional automatic tool changer, the moving distance of the spindle head 60 becomes long, which increases the machine height and lengthens the time required for the tool change operation in the conventional automatic tool changer. There are drawbacks.

[0004]

SUMMARY OF THE INVENTION Therefore, in view of the above problems, an object of the present invention is to eliminate or minimize the impact generated during the tool changing operation without decreasing the operation speed of the spindle head. In addition to the above, it is possible to provide an automatic tool changer which is configured to be capable of exchanging tools with a shorter moving distance of the spindle head than in the past, thereby accelerating a tool exchanging operation.

[0005]

In order to solve the above problems, according to the present invention, a spindle head that rotatably supports a spindle, and
Holds the tool with multiple grips on the circumference
Wherein comprising a rotatably supported by the turret around the predetermined rotation axis, the index the desired tool by indexing operation of the turret at a predetermined exchange position, the turret around said rotary shaft together with the In an automatic tool changer used in a machine tool for exchanging tools between the tool mounted on the spindle and the desired tool by rotating and rotating the spindle toward and away from the spindle, first cooperating with cam roller rotatably mounted on the back, for rotating people create the turret, a first cam provided in front Symbol main spindle head, the turret, the spindle A second cam provided on the spindle head for moving up and down relative to the spindle head in a direction along the center of the second cam roller, and a second cam roller that cooperates with the second cam. , The spindle head moves up and down When the second cam and the second cam roller
It Seung said second cam roller or we receive an action force by cooperation with the turret is configured by including a link mechanism for operating the up and down direction along the center of the main shaft, is vertically operating the spindle head When the turret is moved toward and away from the turret for tool exchange, the turret is simultaneously moved up and down relative to the spindle head to reduce the relative speed of the turret with respect to the spindle head. Characterized by
An automatic tool changer is provided.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, referring to FIGS. 1 and 2, an automatic tool changer according to the present invention has a substantially U-shaped arm member 2 which can move vertically and a plurality of grips 28 on the outer circumference. And a turret 38 for holding the tool by the grip 28. Then, the turret 38, the indexing operation comprises a reduction gear 39 in order to select the desired tool, and is rotatably constructed around a predetermined axis a.
Further, the CNC drill shown in FIG. 1 includes a spindle head 34 that rotatably holds a spindle on which a tool used for machining is mounted, and the spindle head 34 is mounted on the guide rail 1. Is configured to be vertically movable. In the following description, the case where the turret 38 holds ten tool holders on the outer periphery thereof will be described as one embodiment of the present invention.

Referring to FIG. 3, first, the speed reducer 39
Will be explained. In the speed reducer 39, a drive side cam 44 and a driven side cam 42 are rotatably connected to both sides of the reducer 39 by bearing means 50 such as a ball bearing with a cage 46 interposed therebetween. . Still referring to FIG. 4, the driven cam 42 is provided with a cam groove 52, the drive cam 44 is provided with a cam groove 58, and the retainer 46 is provided with a groove portion 54. Each of the groove portions 54 holds one steel ball 48 for transmitting the driving force (see FIG. 3 ).
It is configured to engage with 2, 58. Then, as described below, the rotation of the drive side cam 44 is decelerated by the operation of the ball 48 via the ball 48 and is transmitted to the driven side cam 42.

As shown in FIG. 4 (c), the drive cam 44 is a substantially circular member having a turret gear 30 which engages with the spindle gear 32 of the main shaft of the CNC drill on the outer periphery thereof. A cam groove 58 that engages with the ball 48 for transmitting the driving force is provided. The cam groove 58 is a circular groove with a radius r as shown in FIG. 4 (c), it is arranged eccentrically by eccentricity Q in the radial direction from the center axis of the drive cam 44. The cage 46
Referring to FIG. 4 (b), a columnar protrusion provided with means (see FIG. 3) for fixing the holder 46 to the turret of the tool changer 1 so that the holder 46 does not rotate in the center. 56
Is a substantially circular member having. Then, in the cage 46, an oval groove 54 extending in the longitudinal direction along the radial direction has a reduction ratio n (n = 2, 3, 4, ...) And n.
+1 pieces are arranged at equal angular intervals. FIG.
FIG. 3B shows a case where the reduction ratio n = 6 as one embodiment of the present invention. The length of the oval groove 54 in the longitudinal direction along the axis is at least twice the eccentric amount Q of the eccentric circular cam groove 58 of the drive cam 44. Each of the balls 48 is held in the groove 54. Then, the drive cam 44
The movement of the ball 48 is constrained in the radial direction by the groove 54 with respect to the movement of. That is, the length of the groove 54 in the longitudinal direction is 2Q or more, and the ball 48 is
The drive cam 44 reciprocates once in the groove portion 54 in the radial direction while making one revolution. On the other hand, the driven cam 42, as shown in FIG.
8 is a substantially circular member having petals or starfish-shaped grooves 52 having the same number of irregularities as the reduction ratio n in the radial direction. Similarly, FIG. 4A shows the case where the reduction ratio is 6.

Next, the operating principle of the speed reducer 39 will be described. As described above, while the drive cam 44 makes one round in the cam groove 58 of the drive cam 44 while engaging with the ball 48 held in the groove portion 54 of the retainer 46, the ball 48 is moved by the cam of the driven cam 42. While engaging with the groove 52, it operates to reciprocate once in the radial direction in the groove portion 54. In the cam groove 52 of the driven cam 42, the operation of the ball 48 in the groove portion 54 is exactly one cycle with respect to the central angle φ representing the cam groove 52, such as from apex to apex, that is, a petal-like unevenness. Since n are provided, the center angle φ moves by 2π / n. Therefore, in this embodiment with a reduction ratio of 6, the driven cam 42 is
The drive cam 44 makes one-sixth rotation while making one rotation, so that deceleration of one-sixth can be obtained. Further, the detailed structure and operating principle of the speed reducer can be understood by referring to Japanese Patent Application No. 4-014182 filed by the present applicant. Therefore, if the gear ratio between the spindle gear 32 of the spindle and the turret gear 30 is 3: 5 , one tool can be indexed while the spindle rotates once, and the spindle phase matches the phase before the turret indexing. .

Referring again to FIGS. 1 and 2, the automatic tool changer swings the crank 4 fixed to the spindle head 34 vertically movable up and down around the rotary shaft 18 in the direction of arrow SS. The first cam (hereinafter referred to as a swing cam surface) C _S for causing the crank 4 and the crank 4 are indicated by an arrow L.
A second cam (hereinafter referred to as a lift cam) C _{L for} moving up and down in the direction indicated by S is provided. The crank 4 is fixed to the back surface of the turret 38 holding the tool holder 36 via a plurality of grips 28. Therefore, the turret 38 is configured to be operated by the crank 4 in the directions of arrows SS and LS. A first cam roller (hereinafter referred to as a swing roller) 21 that cooperates with the swing cam C _S is rotatably provided around the rotary shaft 20 at an end portion of the crank 4 opposite to the rotary shaft 18. It is attached. Further, a biasing means 26 is attached to the central portion of the crank 4 via an attachment pin 19, and the crank 4 has the rotating shaft 1
It is urged in the direction of arrow SP with 8 as the center. That is, the swing roller 21 is configured to be biased by the biasing means 26 on the cam surface of the swing cam C _S. Such arrangement swinging the swing roller 21 is the swing is supported on the cam C _S and the swing cam on C _S by relatively operation, in the direction of arrow SS the turret 38 according to the shape of the swing cam C _S Operate.

The rotating shaft 18 is connected to a lift slider 16, and the lift slider 16 is connected to the arm member 2.
It is configured to be movable up and down in the vertical direction indicated by the arrow LS along the linear guide 40 fixed to. A lift link 14 is attached to an end of the lift slider 16 on the opposite side of the rotary shaft 18 via an attachment bolt 15, and the lift link 14 is integrally formed with the lift slider 16 by the arrow. It is configured to move up and down in the direction of LS. A lift lever having two arm members 8 and 6 at an end portion on the opposite side of the attachment bolt 15 in the lift link 14 and rotatable about a rotation shaft 10 is provided with an attachment pin 12 therebetween. Have been installed. The rotating shaft 10 is horizontally attached to the arm member 2, and the lift levers 6 and 8 are attached so as to be rotatable about the rotating shaft 10 in a direction of an arrow LL shown in FIG. ing. In the arm member 6 of the lift lever, the rotary shaft 1
0 and the end portion on the opposite side (hereinafter referred to lift roller) second cam roller that engages the lift cam C _L 2
2 is attached rotatably around a rotary shaft 24. With such a configuration, the lift roller 22 rotates in the direction of the arrow LL by the engagement with the lift cam C _L , that is, the lift levers 6 and 8 rotate about the rotation shaft 10 in the direction of the arrow LL. By moving the lift link 14 and the lift slider 16,
The turret 38 moves up and down in the direction of the arrow LS, and the turret 38 also moves in the direction of the arrow LS (hereinafter, this up-and-down movement of the turret 38 is referred to as a lift operation).

The two cams C _S and C _L used in the automatic tool changer according to the present invention will be described below with reference to FIG. As can be seen from FIG. 5, the swing cam C _S supports the swing roller 21 and has two uneven flat surfaces extending parallel to the central axis (hereinafter referred to as Z axis) of the main axis of the CNC drill. Bearing surfaces C _Sa and C _Sb, and an outwardly convex curved portion C _Sc that substantially defines the movement of the turret 38. Next, the operation of the turret 38 by the cooperation of the swing cam C _S and the swing roller 21 will be outlined below. First, while the swing roller 21 is on the bearing surface C _Sa , the turret 38 does not move and is held in the standby position (see FIG. 6). Then, when the swing roller 21 moves to the start point of the cam surface C _Sc (C _S1 ), the turret 38
Starts a swinging motion around the rotary shaft 18 along the cam surface C _Sc , and the grip 28 engages with the V groove 35 of the tool holder 36. Here, the case where the swing roller 21 is at C _S1 is defined as the origin of the Z axis. Further, the swing roller 21 is
When the turret 38 moves on the cam surface C _Sc and comes into contact with the cam surface C _Sb (C _S2 ), the swing operation of the turret 38 is stopped. At this time, the grip 28 is sufficiently engaged with the V groove 35 of the tool holder 36 and grips the tool holder 36. According to FIG. 5, the two bearing surfaces C _Sa and C _Sb are formed by separate members as a preferred embodiment of the present invention, but it goes without saying that they can also be formed by a single member.

On the other hand, the lift cam C _L is a groove-shaped cam having a substantially key-like shape composed of a straight portion C _La and a curved portion C _Lb extending in the Z-axis direction. The lift roller 22 is configured to roll while contacting the inner surface of the lift roller 22. Outlining the relationship between the turret 38 and the lift cam C _L below. While the lift roller 22 is in the straight portion C _La of the lift cam C _L, the cam lever 6 and 8 does not operate, the turret is not lifted. Then, the the lift roller 22 moves to the curved portion C _Lb, firstly, in the first part of the curved portion C _Lb, the arm member 6 of the lift lever by rotating operation in a clockwise direction, the lift link 14 and the lift slider 16 with arrow L
Move upward in the S direction. This allows the turret 3
8 lifts upward. Next, when the lift roller 22 moves to the latter half of the curved portion C _Lb of the lift cam, the arm member 6 of the lift lever rotates counterclockwise to move the lift link 14 and the lift link. The slider 16 is moved downward. As a result, the turret 38 is pulled down. That is, the turret 38 lifts downward. Incidentally, Z
When the origin of the shaft, that is, the swing roller 21 is at C _S1 , the lift roller 22 is at C _L1 in FIG.

Next, FIG. 6 is a diagram showing the shape of the cam by lowering the spindle head 34 shown in FIG. 1 to the lowest point, and FIG. 6 showing the shape of each cam and the swing and lift operations of the turret. The tool change operation of the automatic tool changer according to the present invention will be described with reference to FIGS. 7 and 8 showing the change amount, the change speed, and the change acceleration. First, when a tool change command is issued,
Completion of spindle orientation is confirmed. At the same time, the spindle head 34 moves upward by rapid movement, and the swing roller 21 moves to the swing operation start position C _S1 , that is, the origin of the Z axis, on the flat bearing surface C _{Sa of the} swing cam C _S. At this point, the spindle head 34 stops and the spindle orientation starts. When the orientation is completed, the spindle head 34 starts moving up again. During this time, the lift roller 22, Z of the lift cam C _L
The lift operation is not performed in the straight portion C _La extending parallel to the axis (the portion indicated by L ₁ in FIG. 8). Next, the swing roller 21 is moved by the upward movement of the spindle head 34.
The curved portion C _Sc of the swing cam C _L is moved, and the turret 38 starts a swing operation of rotating in the counterclockwise direction about the rotation shaft 18. The curved portion C _Sc of the swing cam C _S approaches the V groove 35 of the tool holder 36 without the tip of the grip 28 coming into contact with the spindle gear 32 of the main shaft, and is attached to the tip of the grip 28. The provided roller (not shown) is a V groove 3
After engaging with 5, the roller is shaped so as to move accurately on the V groove. Further, it is desirable to determine the curved portion C _Sc of the swing cam C _S so that the tip of the grip 28 of the turret 38 draws a minimum locus and performs a swing motion.

Further, the spindle head 34 moves upward while linearly accelerating the operating speed, and the swing roller 21 moves to C
Move from _S1 to C _S2 . The acceleration of the swing motion of the turret 28 during this period (S ₁ , S _{2 in} FIG. 7) is a natural acceleration determined by the swing cam shape and the linear acceleration of the spindle head 34. As is apparent from FIG. 1, the swing operation speed of the turret 38, the shape of the swing cam C _S, is determined by the relative speed between the swing roller 21 with the swing cam C _S. Therefore, immediately before the end of the swing motion, the swing motion of the turret 38 is decelerated by lifting the turret 38 in the same direction as the motion of the spindle head 34 to reduce the relative speed between them (see FIG. 7). S ₅ ), the swing operation can be ended without lowering the operation speed of the spindle head 34 and without giving an impact to the grip 28 or the tool holder 36. In order to realize this, at the time of deceleration of the swing operation (S ₃ in FIG. 7, between C _L4 and C _{L2 in} FIG. 8), the lift roller 22 is not connected to the portion of the lift cam C _L between C _L4 and C _L2 . Due to the engagement, the lift levers 6 and 8 are rotated counterclockwise around the rotation shaft 10, and the lift link 14 is rotated.
And the lift slider 16 is moved upward to move the crank 4,
That is, the turret 38 is accelerated in the same direction with respect to the upward motion of the spindle head 34 (L _{6 in} FIG. 8). There Consequently swing motion at the end, that is, (C _S2 in the same manner Fig. 7) the swing roller 21 is C _S2 in FIG. 5 and 6, and the lift roller 22 is C _L2 (C _L2 in the same manner FIG 8) Sometimes, the upper moving motion of the spindle head 34 and the turret 38
The relative speed of the lift operation in the Z-axis direction becomes almost 0 (L _P in FIG. 8, that is, the spindle head 34 operates at a speed corresponding to L _P at this time), and the above-mentioned impact is significantly reduced. Or, it will be removed. This point is 1 of the present invention.
It has one important feature.

After the swing operation is completed, the spindle head 34 moves upward to the turret indexing point by fast-forwarding, and at the same time, the turret 38 starts a lift operation for withdrawing the tool holder 36 from the spindle (during this time, the swing roller 21: (It moves from the point C _S2 to C _S3 , and the lift roller 22 moves from the point C _L2 to C _L3 ). That is, in FIG. 8, after the point C _{L2 of the} lift roller 22, the lift acceleration is in the direction opposite to the Z-axis direction (toward the − side), and the upward lift operation is decelerated. At the end of the swing operation, the crank 4 has a velocity in the same direction as the upward motion of the spindle head 34, so that the crank 4 is once overrun in the same direction as the upward motion of the spindle head 34. From (L _{2 in} FIG. 8), the downward lift operation is started (L _{3 in} FIG. 8). This crank 4
By the lifting operation of the turret 38 and the turret 38 relative to the spindle head 34, it is possible to remove the tool holder 36 from the spindle with a smaller moving distance as compared with the conventional automatic tool changer. It is an important feature of the invention. During this period, the acceleration / deceleration of the crank 4 was linear acceleration / deceleration in order to sufficiently reduce the acceleration (L ₈ and L _{9 in} FIG. 8).

After completion of the upward movement of the spindle head 34 (the state shown in FIG. 1), the spindle spindle 32 of the CNC drill and the turret gear 30 of the speed reducer 39 are engaged with each other. Rotates to perform the desired tool indexing. As described above, since one tool is indexed by one rotation of the spindle, no matter which tool on the turret 38 is selected, the phase of the spindle at the end of the tool indexing operation is: It matches the phase of the spindle orientation. After the turret indexing operation is completed, the spindle head 34 moves downward to the Z-axis origin in the reverse order to the above-mentioned order. Therefore, when the spindle receives the tool holder 36 from the grip 28, the downward motion speed of the spindle head 34 and the relative speed of the turret 38 are substantially zero.
Becomes Simultaneously with the completion of the return swing operation of the turret 38, the spindle head 34 returns to the origin and the tool exchange operation is completed.

[0018]

According to the automatic tool changer of the present invention described above, when the turret swings for tool change, the turret is moved up and down relatively with respect to the spindle head. Since the relative speed to and is small or no, it is possible to minimize the impact caused by the swing motion, which ensures the stability of the tool replacement motion and speeds up the tool replacement motion. Achieved Furthermore, since the turret moves relative to the vertical movement of the spindle head, when the tool holder is pulled out of the spindle or mounted, the tool head can be replaced with less movement than before. As a result, the tool change time was shortened and the device was downsized.

[Brief description of drawings]

1 is an elevational view of an automatic tool changer according to the present invention used in a CNC drill.

FIG. 2 is a plan view of an automatic tool changer according to the present invention used in a CNC drill.

FIG. 3 is a schematic cross-sectional view of a speed reducer used in the turret of the automatic tool changer shown in FIG.

4 is a front view of a driven cam, a retainer, and a drive cam of the speed reducer shown in FIG.

FIG. 5 is a diagram illustrating a tool used in the automatic tool changer according to the present invention .
FIG.

6 is a bottom view of the spindle head of the CNC drill shown in FIG .
Down to a point, the cam of the automatic tool changer according to the invention
FIG.

FIG. 7 is a diagram showing a relationship between a cam (swing cam) for swinging the turret of the automatic tool changer according to the present invention and a swing motion of the turret.

FIG. 8 is a diagram showing a relationship between a cam (lift cam) for lifting the turret of the automatic tool changer according to the present invention and a lift operation of the turret.

FIG. 9 is a schematic elevational view of an automatic tool changer according to the prior art.

[Explanation of symbols]

1 ... Strut 2 ... Arm member 4 ... Crank 6 ... Lift lever 8 ... Lift lever 10 ... Rotating shaft 14 ... Lift link 16 ... Lift slider 18 ... Rotating shaft 21 ... Swing roller 22 ... Lift roller 28 ... Grip 34 ... Spindle head 36 ... toolholder 38 ... turret 39 ... reduction gear C _L ... lift cam C _S ... swing cam

Claims (1)

(57) [Claims] 1. A spindle head (3 ) for rotatably supporting a spindle.
And 4); and a turret (38) which is rotatably supported about a predetermined rotational axis (18) holds the tool by a plurality of grips arranged on the periphery (28), A desired tool is indexed to a predetermined exchange position by an indexing operation of the turret (38), and the turret (38) is also indexed.
Close to the main axis around the rotation axis (18),
An automatic tool changer used in a machine tool for exchanging tools between a tool mounted on the spindle and the desired tool by rotating the turret (38) to rotate on the back surface of the turret (38). Cooperating with a freely attached first cam roller (21), the turret (3
For 8) rotates s work, a first cam provided in front Symbol main spindle head (34) (C _S), the main shaft said turret (38), in a direction along the center of the main spindle A second cam ( _CL ) provided on the spindle head (34) for moving up and down relative to the head (34); and a second cam ( _CL ) cooperating with the second cam ( _CL ). has a second cam roller (22), when said spindle head (34) is operated up and down, the second cam (C _L) and a second cam roller (22)
Acting force by the cooperation of the second cam roller (22)
It Seung Luo received, the link mechanism for operating the up and down the turret (38) in a direction along the center of the main shaft (6,8,14,1
6) and is configured to move the spindle head (34) up and down to rotate the turret (38) toward and away from the turret (38) at the same time for changing the tool. The spindle head (34)
The turret (38) is moved up and down relatively to the turret (38).
Wherein reducing the relative speed with respect to the spindle head (34) of
Automatic tool changer characterized by .