JPH0790446B2 - Indexing control device for turret tool rest of machine tool - Google Patents

Description

TECHNICAL FIELD The present invention relates to a turret tool rest for a machine tool. More specifically, it is to provide an indexing control device for a turret tool base for indexing a turret tool base at high speed.

[Prior Art] When using a plurality of tools for machining a machine tool, a turret tool base is used, and by sequentially turning and indexing, various machining operations can be performed efficiently without changing the tools one by one. ing. For example, in the case of a turret tool stand of a lathe, front cutting, filing, boring, and thread cutting work are efficiently performed by sequentially indexing the tools. Hexagons, flats, drums, etc. are known when classified by the type of tool rest. If the indexing speed of the turret tool base is slow, the actual cutting time becomes short and the cutting efficiency becomes poor.

On the other hand, as the indexing and positioning mechanism of the turret tool base, a curvic coupling mechanism, a method of inserting and positioning a knock pin, etc. are known. Japanese Unexamined Patent Publication No. 62-9853 discloses a drum-shaped cam as an intermittent indexing device, which is not a machine tool for cutting or grinding, but has a plurality of cam followers radially mounted on the circumferential surface of the shaft. There is described an indexing rotary type automatic working device for intermittently rotating and driving. The shape of the cam and the position of the table are stored in association with each other and accurately positioned.

[Problems to be Solved by the Invention] The indexing positioning of the conventional turret tool base described above is
Two operations, an indexing operation for rotating and a clamping operation, are required. After the turret tool base is rotated and indexed to a desired position, the turret tool base is fixed by a means such as hydraulic pressure in the next operation so as not to move. Therefore, there has been a limit to shortening the rotation indexing time of the turret tool base, including the above-mentioned two operations.

The indexing control device as disclosed in JP-A-62-9853 has a camshaft,
The rotation angle must be detected from both cam follower shafts. This complicates the control device. In addition, since positioning accuracy is required, there is a problem that speed cannot be increased.

An object of the present invention is to provide an indexing control device for a turret tool rest of a machine tool, which is optimal for an indexing mechanism that can use a necessary turret surface only by indexing without a clamping operation.

Still another object of the present invention is to provide an indexing mechanism for a turret tool rest of a machine tool that is optimally controlled so that high speed indexing can be performed.

[Means for Solving the Problems] In order to solve the problems, the present invention employs the following means.

a. a turret (7) with tools on each of a plurality of turret surfaces for machining, b. a turret shaft (3) fixed to the turret (7)
A bearing (4) for immovably supporting the turret shaft (3) in the axial direction and supporting a load in the thrust direction, and d. A cam follower (8) provided on the turret shaft (3), e. A cam (20) having a cam surface that engages with the cam follower (8) for rotating the cam follower (8).
F. An indexing motor (26) for driving the cam (20) to index the turret surface; and g. Rotationally drive the cam follower (8) on the cam surface (21). A machine tool having a straight portion (30) forming a non-raceway surface; h. A first dog (45) fixed to the cam (20); and i. A second dog fixed to the cam (20). The dog (46) and j. The second dog (46) is detected and the turret (7) is detected.
Stop confirmation sensor (44) for confirming whether or not is indexed to a predetermined angle, and k. A stop that detects the first dog (45) and issues an index stop signal to the indexing motor (26). Command sensor (43)
L. The time constant is set so that the cam surface (21) and the cam follower (8) are engaged with each other at the position of the straight line portion (30) to receive the output signal of the stop command sensor (43) and stop. This is an indexing control device for the turret tool rest of machine tools consisting of a control device and m.

EXAMPLES Examples of the present invention will be described below with reference to the drawings. What is shown in FIG. 1 is a partial cross section of the turret tool base 1. The turret body 2 has a box shape, has an internal space, and is made of a casting material. The turret body 2 is mounted on a carriage (not shown), and is machined by a tool provided on the turret 7 by the movement of the carriage during cutting. Both ends of the turret body 2 are rotatably supported by bearings 4 and 4 that bear a load in the thrust direction.

A flange surface 6 is provided at one end of the turret shaft 3.
An output shaft 5 is provided on the flange surface 6, and a turret 7 is fixed in close contact with the output shaft 5 and the flange surface 6. The turret shaft 3 between the bearings 4 and 4 is provided with a plurality of cam followers 8 whose center axis is oriented in a direction perpendicular to the axis of the turret shaft 3. The cam follower 8 is rotatably provided on the cam follower shaft 9 via a bearing or the like.
The cam follower shaft 9 is fixed to the turret shaft 3. A plurality of cam follower shafts 9 and cam followers 8 are provided on the outer periphery of the turret shaft 3 at equal intervals.

On the other hand, a protrusion 21 having a trapezoidal spiral cross section is formed on the outer periphery of the roller gear cam 20 (FIG. 2). The cam follower 8 is engaged with the protrusion 21. The roller gear cam 20
Rotate about axis 29. The drawing shown in FIG. 3 is a developed view of the roller gear cam 20. The projection 21 is sandwiched by a cam follower 8 to rotate the turret shaft 3. Protrusion
21 includes an inclined portion 31, a straight portion 30, and a steep inclined portion 32. The inclined portion 31 and the steep inclined portion 32 have a certain pitch and do not have a spiral shape along the axis 29 of the roller gear cam 20, but the pitch is not constant. The straight portion 30 has an advantage that it does not affect the stopping position of the turret shaft 3 even if the roller gear cam 20 has a slightly poor angular positioning accuracy. This part is used for indexing and positioning the turret shaft 3. Therefore, the rotation speed of the roller gear cam 20 can be increased. On axis 22,
Timing pulley with constant pitch teeth formed on the outer circumference
23 is fixed. A toothed belt 25 is engaged with the timing pulley 23. The other timing pulley 24 is engaged with the other of the toothed belt 25. The timing pulley 24 is directly connected to and driven by the indexing motor 26.

FIG. 4 is a functional block diagram of the tool turret tool post. The NC controller 40 is a known numerically controlled machine tool. When a T-code command, which is a turret tool table indexing command, is issued from the NC control device 40, it is transmitted to the controller 41. When the controller 41 receives this command,
The tool post controller 42 is instructed to send forward / reverse rotation commands and start commands. The turret controller 42 is an indexing motor.
Electric power is output to 26 to rotate the indexing motor 23.

The rotation of the indexing motor 26 is transmitted to the turret shaft 3 to index the turret 7. Dog on roller gear cam 20
There are 45 and 46. (FIG. 5) A stop command LS43 and a stop confirmation LS44 are provided in the turret main body 2 corresponding to the dogs 45 and 46, respectively, and operate corresponding to the indexing surface of the turret 7. That is, the stop command LS43 is provided so that the indexing surface is located at the indexing position. Stop command
When the LS43 operates, it sends a signal to the controller 41. The stop confirmation LS44 is provided at a position where the angular position of the turret 7 divided into a predetermined angle can be confirmed. When the stop confirmation LS44 is activated, a signal is sent to the controller 41. Roller gear cam 20
Since the dogs 45 and 46 are provided on the to detect the angular position, the rotation range is wide, so positioning can be performed with a little roughness.

Operation Flow of Turret Tool Table The time chart shown in FIG.
6 is a time chart showing the operation of a roller gear cam 20 and a stop command LS43. Since the indexing motor 26 and the roller gear cam 20 are directly connected by the toothed belt 25, they operate simultaneously. tM is the time when the indexing motor 26 is powered off. tB is the stop time of the roller gear cam after the power of the indexing motor 26 is cut off. The roller gear cam 20 does not stop immediately. This is because there is a delay determined by the time constant such as the inertia of the rotor of the motor and the inertia of the roller gear cam 20. The tA point, which is the starting point for outputting the stop command signal, is
This is the end point of the stop command LS43.

| tM−tA | is the time due to the processing delay until the start command of the indexing motor 26 is cut off after receiving the stop command. | tB−tM |
Is the time (time constant) until the indexing motor 26 stops. Point A in Fig. 5 passes stop command LS43 | tB
After -tA |, the roller gear cam 20 stops at point B. This stopping point will be explained with reference to FIG.
This is the point of contact with 30. Design is performed so as to operate at maximum speed in consideration of the time constant.

The flow chart shown in FIG. 7 shows the operation of the turret tool base 1. In step, the NC controller 40 issues a T code command, that is, an index command for the turret tool base 1. Raise an alarm in steps. If YES, it makes an arbitrary shortcut decision. The technique for making this determination is a conventionally known technique. In this step, it is determined whether the rotation is normal or reverse. If it is reverse rotation, a reverse rotation command is issued in steps.
If it is forward rotation, a forward rotation command is issued in steps.

The number of surfaces of the turret 7 is counted in steps. This counting method counts +1 for forward rotation and -1 for reverse rotation. If the numbers counted in the step match, it is determined that the indexing surfaces match, and the process proceeds to step. If the index surfaces do not match, the process ends. At the step, wait for the signal of the stop command LS43, and proceed to the step. The controller 41 issues a turret stop command in steps.

In step, the receipt of the stop confirmation signal from the stop confirmation LS44 is confirmed, and if YES, the T code is completed in step. This indexing time is an extremely short time of 0.1 seconds for one surface indexing. If you cannot confirm with step, proceed to step. If you cannot confirm with step, proceed to step.
Issue an index alarm.

[Other Embodiments] The indexing mechanism described above uses a roller gear cam and a cam follower, but is not limited to this.
As described above, another similar cam mechanism may be used as long as there is no play between the cam followers.

[Effects of the Invention] As described above in detail, the present invention does not have a clamp mechanism and a speed change mechanism, and therefore, extremely high-speed indexing is possible with a relatively simple structure.

[Brief description of drawings]

FIG. 1 is a partial sectional view of a turret tool base of the present invention, FIG. 2 is a side view of a roller gear cam and a cam follower portion, FIG. 3 is a development view of a roller gear cam, and FIG. 4 is a control block diagram.
FIG. 5 is a detection mechanism for detecting the angle of the roller gear cam, FIG. 6 is a time chart, and FIG. 7 is an index operation diagram of the turret tool base. 1 ... Turret tool base, 2 ... Turret body, 3 ... Turret shaft, 7 ... Turret, 8 ... Cam follower, 9 ... Cam follower shaft, 26 ... Indexing motor, 41 ... Controller, 43 ... Stop command LS, 44 ... Stop confirmation LS, 45,46 ... Dog

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takayuki Nagasawa 1 Abiko, Abiko City, Chiba Hitachi Seiki Co., Ltd. (56) References JP 59-169752 (JP, A) JP 52-81681 JP, A) Actually open 61-85340 (JP, U)

Claims (1)

[Claims] 1. A turret (7) provided with tools on a plurality of turret surfaces for machining, and b. A turret shaft (3) fixed to the turret (7).
A bearing (4) for immovably supporting the turret shaft (3) in the axial direction and supporting a load in the thrust direction, and d. A cam follower (8) provided on the turret shaft (3), e. A cam (20) having a cam surface that engages with the cam follower (8) for rotating the cam follower (8).
F. An indexing motor (26) for driving the cam (20) to index the turret surface; and g. Rotationally drive the cam follower (8) on the cam surface (21). A machine tool having a straight portion (30) forming a non-raceway surface; h. A first dog (45) fixed to the cam (20); and i. A second dog fixed to the cam (20). The dog (46) and j. The second dog (46) is detected and the turret (7) is detected.
Stop confirmation sensor (44) for confirming whether or not is indexed to a predetermined angle, and k. A stop that detects the first dog (45) and issues an index stop signal to the indexing motor (26). Command sensor (43)
L. The time constant is set so that the cam surface (21) and the cam follower (8) are engaged with each other at the position of the straight line portion (30) to receive the output signal of the stop command sensor (43) and stop. A turret tool stand indexing control device for machine tools consisting of a control device and m.