JPH0327321B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic workpiece changing device in a turning machine tool.

2. Description of the Related Art Various types of conveyance devices have been known in the art for turning machine tools, such as for exchanging a raw material and a processed workpiece, or for carrying in a material and carrying out a processed workpiece.

However, conventional exchange or transfer devices are generally installed independently of the machine tool and assembled externally, and are then attached to the completed machine tool. It is complicated and expensive, and requires centering work during installation, that is, positioning the conveyor device relative to the chuck of the machine tool.
However, this was a tedious task.

However, it is not necessary for all parts to have the above-described configuration, and the configuration and assembly work can be simplified if some functions are shared with existing functions of the machine tool.

The present invention was developed to solve the above-mentioned conventional problems, and has a structure in which a workpiece on the in-situ can be quickly exchanged with a machined workpiece in the chuck of a machine tool, and this exchange device is integrated into the machine tool. An object of the present invention is to provide a device in which the rotational movement of the exchange arm is performed by a drive source common to the main shaft drive mechanism.

Another object of the present invention is to provide a device in which the axial movement of the exchange arm is a common drive source for the drive mechanism of the tool post.

As a result, the drive source that was conventionally provided independently for swinging the arm has been omitted, and the swinging mechanism has been simplified. Furthermore, by integrating this device into the machine tool, centering work can be omitted, contributing to a reduction in manufacturing man-hours.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a turning machine equipped with the device of the present invention. The one shown shows an automatic workpiece exchange device with a chute attached.
A tool turret 5 and a tool holder 6 are mounted on a slide 4 that moves back and forth (X) and left and right (Z) by guides 2, 2 provided on the headstock 1 and a guide 3 of a saddle guided by the guides 2, 2. , and tool 7 are held. 8 is a ball screw for moving the saddle 3a, and 9 is a drive motor for driving the saddle 3a. Further, the slide 4 is driven in the X direction by a motor 9a and a ball screw 8a.

On the other hand, the main shaft head 10 is rotatably provided with a main shaft 26 (see FIG. 2), and a chuck 11 is attached to one end.
is installed. A workpiece 13 is gripped by gripping claws 12 attached to the chuck 11, and the workpiece 13 is cut by the tool 7.
The workpieces 13 are sequentially slid down using the slope of the insert 14, and mounted on one side of the automatic exchange arm 16 by the pushing action of the cylinder 15.
The chuck 11 is attached to and detached from the chuck 11 by moving the automatic exchange arm 16 back and forth and rotating. 1
4a is an outshoot for taking out the processed workpiece. The workpiece 13 is a main shaft drive source 20 such as a motor.
It is rotated by a pulley 17, a pulley 18 on the main shaft side, and a belt 19 connecting both pulleys.

FIG. 2 shows an example of a rotation transmission mechanism for driving the automatic exchange arm 16. As shown in FIG. Therefore, parts common to those in FIG. 1 will be described with the same reference numerals.

As mentioned above, 20 in the figure is the motor, and the pulley 1
7, 18 The rotational force is transmitted to the gear shaft 21 by the belt 19, and the gear shaft 21 is connected to the main shaft head 10.
A gear 2 is rotatably supported through bearings 22, 22, and selectively meshes with gears 27, 28 of the main shaft 26.
4 and 25 are provided.

The gears 24 and 25 are integrated and are attached so as to be shifted in the axial direction of the gear shaft formed on the spline 21' in order to obtain different rotational speeds and rotational torques of the main shaft.

Therefore, the main shaft 26 receives the torque of the gear shaft 21 to rotate the workpiece 13 held by the chuck, and is equipped with a large gear 28 and a small gear 27 that are fixed to the main shaft 26 by a key 26'. The gear 27 and the gear 24 and the gear 28 and the gear 25 are selectively engaged with each other and are configured to rotate at different rotational speeds with different speed ratios.

The present invention accommodates the rotational drive mechanism for the main shaft 26 having the above-mentioned configuration, in which the rotating shaft 29 for automatic workpiece replacement is housed in the same outer casing, and the rotating shaft 29 freely rotates by receiving the rotational force of the main shaft 26. an engaging body for causing
That is, it is characterized by the provision of a gear that can be freely engaged and detached.

That is, between the main shaft 26 and the turning shaft 29, the intermediate shaft 3
0, a small gear 31 and a large gear 32 are fixed to the intermediate shaft 30 via a key 30', and the gear 32
mesh with gear 27. On the other hand, the pivot shaft 29
Also, a large gear 33 and a small gear 34 are fixed via a key 29', and as the pivot shaft 29 moves in the axial direction, the large gear 33 is attached to the small gear 31 fixed to the intermediate shaft 30, respectively. Alternatively, the small gear 34 is configured to selectively mesh with the large gear 32.

Reference numerals 35 and 35' denote driving bodies consisting of cylinders for sliding the rod 36 left and right as indicated by arrow S, thereby moving the pivot shaft 29 in the axial direction;
The rod 36 and the pivot shaft 29 are connected through a shifter 37, and the pivot shaft 29 also slides left and right in synchronization with the left and right movement of the rod 36.

Note that 38 is a fluid distributor for sending fluid to a driving source for opening and closing the gripping devices 16a and 16b provided at the tip of the exchange arm 16, and 39a, 39b, and 39c are provided on the pivot shaft 29 A limit switch for confirming the position of the rotating shaft 29 and stopping the movement, which is placed at a position where the dog 40 contacts the rotating shaft 29, and 41 is a rotating shaft 29 fixed to the bracket 43.
This is a rotation prevention guide groove, into which one end of the rod 42 protruding from the pivot shaft 29 is fitted.

The operation of the apparatus of the present invention having the above configuration will be explained below. Now, when driving the cylinders 35, 35' and moving the rotation shaft 29 left and right by the left and right movement of the rod 36, the position shown in FIG. 2 (solid line) is
is temporarily set as the first position _S1 . That is, in the first position, the gears fixed to the pivot shaft 29 and the intermediate shaft 30 are not engaged, and the pivot shaft 29 is prevented from rotating and is in a retracted position on the headstock side.

Next, the rod 36 is slid to the right (dotted line) by applying pressure oil to the cylinder 35' and draining the oil inside the cylinder 35, so that the dog 40 of the rotation shaft 29 reaches the position of the limit switch 39b. FIG. 3 shows the state in which it has been moved, and this position is set as the second position. That is, in the second position, the large gear 33 of the rotating shaft 29 and the small gear 31 of the intermediate shaft 30
are engaged, and the automatic exchange arm 16 extends and moves to the _S1 position.

This second position is a position where the workpiece can be transferred between the gripping device of the exchange arm and the chuck.

FIG. 4 shows a state in which the cylinder 35' is further driven and the dog 40 of the pivot shaft 29 is slid to the limit switch 39c position, and this position is set as the third position.

That is, in the third position, the small gear 34 of the pivot shaft 29
and the large gear 32 of the intermediate shaft 30 are meshing and rotating, and the automatic exchange arm 16 further extends and moves to the _S2 position. This third position is a position where the workpiece gripped by the gripping device of the exchange arm is removed from the chuck side, and the exchange arm can rotate while gripping the old and new workpieces.

Of course, the means for slidingly moving the pivot shaft 29 is not limited to the above-mentioned cylinder device, but for example, as shown in FIG. The shifter 37 may be engaged with the pivot shaft 29 to move the pivot shaft 29 left and right as in S _{1 ,} S _{2 , and} S ₃ .

Next, the operation mode of the apparatus according to the present invention will be explained in detail with reference to FIG. In FIG. 1, a workpiece 13 sliding down inside an insert 14 is positioned at a predetermined position.
It shows how it is pushed out by the piston 15' of the cylinder 15 and gripped by the gripping devices 16a, 16b of the automatic exchange arm 16. At this time, the automatic exchange arm 16 is in the first position.

Next, FIG. 2 shows a state in which the workpiece 13 is gripped and the automatic exchange arm 16 is set at the second position.
That is, reference numeral 13' indicates a processed workpiece gripped by the chuck 11, which occupies a position coincident with and parallel to the position of the unprocessed workpiece 13. Next, FIG. 3 shows a state in which the pivot shaft 29 is rotated 90 degrees in the second position and the automatic exchange arm 16 grips the works 13 and 13' at both ends. At this time, chuck 1 of workpiece 13'
1 is in the free state. Next, as shown in FIG. 4, the pivot shaft 29 is further extended to _S2 , the automatic exchange arm 16 is set to the third position, and then the pivot shaft 29 is extended as shown in FIG.
Rotate 9 180 degrees to create work 13 and work 1.
3' is reversed, and then, as shown in FIG. 6, the rotating shaft 29 is shortened and the automatic exchange arm 16 is returned to the second position, while the unprocessed work 13 is inserted and fixed into the chuck 11.

Next, as shown in FIG. 7, the rotation axis 29 is extended to S ₂ again to complete the gripping operation of the workpiece 13, and then, as shown in FIG. 8, the automatic exchange arm 16 is rotated 90 degrees, and then As shown in FIG. 9, the automatic exchange arm 16 is reset to the first position by shortening the pivot shaft 29 to its original position, the automatic exchange arm 16 is released from gripping the workpiece, and the machined workpiece 13' is output. It is discharged to 14a.

FIG. 7 shows another embodiment of the present invention, in which an engaging member 37-1 is attached to the tool post instead of the cylinders 35, 35' shown in FIG.
By directly connecting this engaging member to the pivot shaft 29a and moving it in the axial direction using the operation of the tool post, the same operating mode as the example shown in FIG. 2 can be obtained. In FIG. 7, numeral 6 indicates a turret head attached to the tool rest. In this case, the axial movement of the exchange arm also uses the existing drive body of the machine body, and a dedicated drive source for the device is not required. FIG. 8 is a front sectional view showing an example of the exchange arm, and FIG. 9 is a plane sectional view thereof.
The workpiece 13 and the workpiece 13' are gripped and released by the interaction of the cylinders S _{1 and} S ₂ housed in the support member 83 and the drive gears G _{1 and} G ₂ with respect to the gripping claws 81 and 82. In this embodiment, the cylinders are operated independently.
However, since this mechanism is well known, detailed explanation of its operation will be omitted.

The turning operation of the automatic exchange arm 16 in the operation mode shown in detail above is such that the rotation angle is different from that of the main shaft 2.
6. It is determined by the gear ratio of various large and small gears disposed on the intermediate shaft 30 and the rotating shaft 29, and the rotation angle of the main shaft drive source 20 such as a servo motor, and is determined by the axial movement of the automatic exchange arm. By automatically controlling these, all operations can be automated.

An example of the control configuration will be described below.
FIG. 10 is a block diagram showing the overall circuit configuration, basically a control circuit 51 for the CPU 50.
Consists of various parts attached to a crystal oscillator 52 and a bus 53, including a program PROM 54 for NC control, and an interrupt timer control circuit 5.
5. RAM 56 for temporary memory, bubble memory 57 for machining program, servo control device 5
8. Drive NC control and spindle motor control device 62 by paper tape reader PTR 59, input/output interface 60, keyboard and display device 61, etc.

FIG. 11 is a control block diagram including a spindle positioning loop, in which the spindle of an NC machine tool is provided with a rotational position detector and has the function of positioning the spindle at any fixed angle position. To describe this in detail, the S register 63 in the figure sets the speed in the case of spindle speed control, so that this value is input to the D/A converter 65 via the switching gate 64; When positioning the spindle, set the spindle positioning speed in the S register 63.
, the switching gate 64 and the D/A converter 6
By activating the drive amplifier 66 of the motor M via 5, the rotational position detector PG of the motor M is activated.
Rotate the main shaft in the normal direction until a one-rotation signal is generated. When the PG signal (grid signal) is turned on, the switching gate 64 is switched to the error counter 67, and at the same time, the feedback gate 68 from the rotational position detector PG to the error counter 67 is opened, thereby forming a closed loop. The opening and closing of the gate 68 is controlled by an interrupt control circuit 69 operated by a grid signal.

The spindle is accurately positioned by controlling the error counter so that the contents of the error counter become zero through the closed loop described above. The contents of the error counter include the error between the start position of the spindle (hereinafter referred to as the spindle origin) and the detector grid point, and the error in the shift amount (= rotation amount) of the spindle origin, which are input into the respective memory addresses as parameters. Just set it.

Next, the error counter 67 is a presettable addition/subtraction counter, and the output to the D/A converter 65 has a limiter function. That is, the first
The output of the error counter 67 shown in Figure 3A is the D/A
The pattern shown in the limit portion L shown in FIG.
In other words, the limit portion L determines the upper limit (or lower limit) of the positioning speed of the spindle, and this limiter function allows the output to the D/A converter 65 to be kept below a certain value to determine the positioning speed. can.

In addition, if it is necessary to determine the forward or reverse positioning direction of the spindle, the shift amount of the spindle origin (i.e., the rotation amount)
The second and third shift amounts can be treated as errors with respect to the spindle origin.

FIG. 12 is a flowchart summarizing the above-mentioned spindle positioning control method as an operation system diagram. As can be seen from the same chart, first the rotation is performed in speed control mode, and 1
The rotation detection signal will switch the gate to closed loop control mode. Therefore, smoother and faster positioning can be achieved by matching the direction of rotation of the main shaft in the speed control mode and the closed loop control mode. Furthermore, the shift amount set in the error counter 67 must be a value that matches the direction of rotation in the speed control mode, and when the positioning direction is reversed, the shift amount must be set as a two's complement number. Good.

As explained in detail above, the automatic tool and workpiece changing device according to the present invention has a drive source for the spindle.
The rotation and positioning drive sources of the ATC device are the same, and a means for transmitting and disconnecting rotational force is provided between the two, making it possible to unify the drive control system, as well as the ATC arm rotation drive source. Since no power source is required, the entire device can be made more compact.
Since a D/C motor for the spindle is used as the drive source, the slow-up and slow-down can be adjusted according to the size of the workpiece. Furthermore, when transferring the arm, the arm gripper position is on the spindle center line, making it possible to exchange workpieces and tools on the tool rest using one ATC arm. The back-and-forth movement of the ATC arm not only provides flexibility in responding to the length of the workpiece, but also has the advantage of being able to change sequence motions and be applied to bar pull-out operations for bar work by back-and-forth movement of the arm. It is effective mainly when applied to NC machining machine tools.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a perspective view illustrating an overview of the entire device, FIG. 2 is a sectional view of essential parts showing an example of a rotational force transmission mechanism, and FIG.
FIG. 4 is a sectional view of an embodiment showing the mode of operation, FIG. 5 is a sectional view of another embodiment showing the sliding mechanism of the rotation shaft, and FIG. 6 is a section explaining the mode of operation of the device according to the present invention. FIG. 7 is a cross-sectional view of main parts showing another embodiment of the present invention, FIG. 8 is a front cross-sectional view showing an example of the ATC arm, FIG. 9 is a plan cross-sectional view of the same, and FIG. 10 is an electronic FIG. 11 is a control block diagram including a main shaft positioning loop,
FIG. 12 is a flowchart summarizing the main shaft positioning control method as an operation system diagram, and FIG. 13 is a graph of the output characteristics of the error counter. 1... Headstock, 4... Slide, 5... Tool turret, 6... Tool holder, 7... Tool, 8...
Ball screw, 9...drive motor, 10...spindle head, 11...chuck, 12...gripping claw, 1
3, 13', 13''... Work, 14... In-shu, 15... Cylinder, 16... Automatic exchange arm, 14a... Outshoot, 20... Main shaft drive source, 21... Gear shaft, 26... Main shaft ,28,3
2,33...Large gear, 27,31,34...Small gear, 29...Rotating shaft, 30...Intermediate shaft, 35,3
5'... Cylinder, 36... Rod, 37... Shifter, 38... Distributor, 39a,
39b, 39c...limit switch.

Claims (1)

[Scope of Claims] 1. A headstock, a main shaft rotatably supported by the headstock, a first gripping device provided at one end of the main shaft for gripping a workpiece, and a rotation drive for rotating the main shaft. a mechanism, an engaging body that is rotatable by being engaged with the rotational drive mechanism, a shaft that integrally holds the engaging body and is rotatable and movable parallel to the axis of the main shaft; a driving body that moves parallel to the axis; an exchange arm that is provided at one end of the shaft and is rotatable in a direction perpendicular to the main shaft axis; and the first gripping device that is provided at the tip of the exchange arm. 1. An automatic workpiece exchange device for a machine tool, comprising a second gripping device that transfers a workpiece between the two grippers, and an exchange arm that is rotated by a rotational drive mechanism of a main shaft to automatically exchange a workpiece. 2. A patent in which when the shaft body moves to a plurality of predetermined positions in the axial direction, the rotating position of the exchange arm can be changed by engaging the engaging body with different positions of the rotational drive mechanism of the main shaft. Claim 1
Automatic workpiece changing device for machine tools as described in Section 1. 3. A tool post that is driven to process a workpiece is configured to be engageable with the exchange arm as the driving body, and the exchange arm is moved parallel to the spindle axis by the operation of the tool post. An automatic workpiece changing device for a machine tool according to claim 1. 4. The automatic workpiece changing device for a machine tool according to claim 1, wherein the engaging body and the rotational drive mechanism are gears.