JPH0310701A - Working by spindle moving type automatic lathe - Google Patents

Abstract

PURPOSE:To facilitate the formation of a working program while maintaining the high reliability and productivity of a cam type automatic lathe by executing the working program by means of respective servo motors in the directions of Z, X and performing the X direction control in its form converted to a cam angle. CONSTITUTION:The mounting angles, heights and upward and downward angles of respective cams 20 are previously stored in a controller 40, and a cam shaft 24 is provided with respective cams (only the cam 20 is shown in the drawing) at mounting angles according to a program so that respective tool rests 16 are driven by a mechanism consisting of a link 17, rod 18 and cam follower 19. A spindle head 2 is moved by a servomotor 11 to a position in the direction Z by the command of the controller 40 according to the program, and a blank is brought to a working start position. A predetermined tool rest 16 is selected by one cam 20 and the cam shaft 24 is rotated by a servo motor 25 so that a cutter 15 cuts the blank by the converted rotational angle of the cam 20. When the blank is cut by a predetermined amount, the cam shaft 24 is stopped and the servo motor 11 is again rotated so that the spindle 1 is moved in the direction Z and the cutter 15 is fed in the direction Z to work the blank in said direction.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a machining method using a moving spindle type automatic lathe.

[Conventional technology]

Spindle-moving lathes are broadly classified into cam-type automatic lathes and NC-type automatic lathes based on the control type of their operation.

In the cam type, selection of the cutting tool, cutting, movement of the spindle, and other operations are all performed by the cam. The cams have a unique shape as many as the number to be operated on the camshaft, and there are 36 cams.
It is provided within a range of 0°. Therefore, since it has quick responsiveness and a short processing cycle, it is suitable for processing products with relatively simple shapes that can be processed in a short time, and is particularly suitable for mass production processing. He is also highly trustworthy.

For example, such a cam type is described on page 48 of the Automatic Lathe Handbook (Kogyo Chosenkai Co., Ltd., September 1968).
published on the 30th of each month). In this method, the driving force of the motor rotates the main shaft and also rotates the camshaft via a transmission to select the blade and make the cut.
Furthermore, various operations such as feeding during cutting are also performed by each cam on the camshaft.

Furthermore, in the case of the NC type, the various operations described above are performed by independent driving elements according to a program. Therefore, by changing the program, it is possible to freely respond to changes in the shape of the product. For example, Tokuko Sho 60-5976
No. 3 shows an example in which the selection of cutlery is made by NC. In this known device, a plurality of tool rests are arranged radially with respect to the main shaft, and each tool rest can be moved in and out of the main shaft by a cylinder attached to each tool rest.

Then, to select the cutter, NC signals are used to drive a predetermined cylinder to move one tool rest forward along the main axis and bring it to the processing position, while the other tool rests are maintained in a retreated standby position. .

Next, in Utility Model Application No. 63-103901, a selection mechanism consisting of a cylinder was installed in each of the connecting ronds and the swivel arm for cutting provided in each of the plurality of tool rests, and a selection mechanism consisting of a cylinder was installed in response to an NC signal. A predetermined cylinder is operated to select the corresponding tool rest. Furthermore, in Japanese Patent Publication No. 46-26392, in place of the above-mentioned selection mechanism, each clutch is provided, and a predetermined tool rest is selected by operating only one of them.

[Problem to be solved by the invention]

However, the conventional device described above has the following problems.

First, in the cam type, both the cutting of the selected blade (movement in the X-axis direction) and the feeding of the main shaft (movement in the X-axis direction) are performed by respective cams provided on one camshaft. Therefore, the shape of the cam is such that, for example, when the blade is cutting, the main shaft does not feed, so when one of the cams is at a cam angle for feeding, the other is at a cam angle that does not operate. Since the cam typically cycles within 360 degrees, the result is that the available cam angle is reduced accordingly. In particular, it is not desirable in the design of the cam to perform a large amount of feed with a narrow cam angle. This results in limitations on feed rate and machining complexity.

Additionally, if the product changes, a new cam must be designed and manufactured for that product, and the cam set must be changed, so the so-called product manufacturing start-up time is much longer than with an NC machine. , it is unsuitable for high-variety, low-volume production.

In addition, with the NC method, there is no such restriction,
It can easily accommodate changes in products, which can be said to be a drawback of the cam type, that is, small-lot, wide-variety machining. However, it takes time to operate and check the operation of cylinders, clutches, etc. as actuators, and the machining efficiency decreases when machining parts with relatively simple shapes. Moreover, since an actuator is required for each turret, the device becomes expensive.

However, simply replacing the conventional cam type with an NC type will not solve the problem of the unused cam angle mentioned above, and a special cam that corresponds to the shape and dimensions of the product must be prepared for each product. .

Furthermore, although the problem of the unutilized cam angle remains, it is also possible to use a so-called standard cam for the cam itself and operate it proportionally according to the dimensions of the product. However, in this case, in order to process the product without any problems, use a machining program that is based on the center of the workpiece, such as that used in the NC lathe in -a. , it is necessary to convert it into a machine control program on the control device side, but this causes the following problems.

That is, the particular diameter A in FIG. 5 of the accompanying drawings.

When machining a cylindrical body with steps B and C, if the machining start position P1 of the first selected cutting tool P is the maximum cutting position of that cutting tool as shown in the figure, the cam follower that operates that cutting tool is the sixth cam follower. As seen in the developed view of the cam shown in Figure (A), the rotation angle from the cam shaft origin should be selected so that it is located at the point Fm, that is, the highest lift point of the cam.Then, as the machining progresses, Rotate the cam and
Machining of the cutting tool is completed at the point of the cam follower F1 shown in ), and it can be retreated to the point FE (the lowest point of the cam). In FIG. 6(A), the angle β is the cam angle for machining, and the cam angle up to the corner T machining start (end) position.

However, such machining is only possible in the first process when the previous product is completely cut off and the next product begins machining, and in the case of the second and third cutting tools. 0 For example, as shown in Figure 7, it is often impossible to
When machining starts from point iO and the cutting edge cuts in, in a work where machining is completed at point Pn', Pn'
The point will be the highest point of the cam, and in this machining program, the highest point of the cam will be at the end of the program for that cutting tool.

However, in this case, the point of the cam follower F1'' at the point Pn' of the cutting tool cannot be selected as the point F shown in FIG. 8(B) which jumps over the highest point of the cam,
The point on the rising side of the cam shown in (camshaft rotation angle θ−αl)
The location must be selected.

Further, selection of this point is not possible in a general NC program that uses a sequential operation execution method.

Also, as seen in Figures 7 and 8 above,
Even if machining starts from the same point P1''+Pl'' (position K from the center of the workpiece), if the maximum depth of cut of the cutting tool is different (i.e. Pn''=Kh+*Pn'''-
(-hz), the machining start point of the cam for the cam follower will be different.

The position of the cam in this case is determined by how far the position of the maximum cutting tool is from the center of the workpiece, or in other words, the distance between the machining start point Pl'+PI'' and the maximum cutting tool position Pn', P
The position of the cam and cam follower at the cutting tool position at the start of machining changes depending on the distance from n'' and the difference in h2 (Fig. 6 (C)
and (D)).

That is, as shown in FIG. 6(C), the machining start point PI° in FIG. 7 is set at the position θ-α, and the machining start point Pn'' in FIG. It is clear that the cam and cam follower must be started if the selected cutting tool completes the work even if the cam on the rising side is used.
Of course, it must end at point i.

In addition, the positive and negative signs of the tool correction of the cutting tool are opposite when using the upward side of the cam and when using the downward side of the cam, so when using the upward side, the sign of the tool correction must be reversed.

Creating a machining program taking into account the above conditions not only places a very heavy burden on the programmer who uses it, but also leads to the occurrence of programming errors, which is a major problem.

The purpose of the present invention is to solve such problems and provide a machining method that takes advantage of both the cam type and the NC type, and allows easy programming and error-free programming using a main-spindle moving automatic lathe. It is something.

[Means to solve the problem]

According to the present invention, the above objects include a main shaft that can grip and rotate a material that is rotatably and slidably guided by a push and move in the Z-axis direction, which is the axis thereof; A plurality of turrets that advance in the X direction toward the main spindle so that a predetermined one can be selected, a servo mechanism that moves the main spindle in the Z direction according to a set program, and a servo mechanism that corresponds to each of the plurality of turrets mentioned above. , a main-spindle movable lathe comprising a camshaft that is provided with a cam for selecting the tool post and cutting the blade and is rotated by a servo mechanism under a setting program, and a control device that controls the servo mechanism and the camshaft. This is a processing method in which the mounting angle, cam height, ascending angle and descending angle of each cam are stored in advance in the control device, and then a processing program for product processing is input, and then the control device executes the above-mentioned steps. Read the machining start position and maximum cutting position in the X direction of the blade corresponding to each cam from the machining program, select the blade by rotating the cam shaft by the mounting angle of the cam corresponding to the blade, and then select. The distance between the machining start position and the maximum depth of cut position of the cutter corresponds to the cam height, and the rotation of the camshaft by angle is executed using the upward and downward angles of the cam to execute the movement program in the X direction of the above mentioned cutter. This is achieved by controlling the rotation of the camshaft by converting it into a program, and controlling the movement of the main shaft in the Z direction using a servo mechanism according to the set program.

[Effect]

According to the present invention, the cam corresponding to the selected cutter is selected by rotating the cam shaft by its mounting angle in accordance with a command from the control device, and the rotation of the cam causes the cutter to move in the X direction. Machining is performed by independently moving the blade in the Z direction using a servo mechanism.

At that time, program conversion for controlling the camshaft is performed in the following manner.

■In advance, set the standard cam installation angle position, cam height, ascending angle, and descending angle as parameters in the NC, which are data necessary for tool selection and camshaft angle control. Even if the machining program, ie, the product, changes, these data will not be changed.

■Prior to converting the program, the manual machining program for each product is read and the machining start position and maximum cutting position of each tool are stored in the internal memory so as to correspond to each tool number. Thus, by reading the machining program prior to execution, the maximum cutting position of each tool can be determined.

■Then, while sequentially reading the machining program, proportional distribution is performed to the camshaft angle based on the data set as parameters. The problem of the same tool movement position on both the up and down sides of the cam is also due to the fact that the maximum cutting position of each tool is known, so while reading the machining program sequentially, the movement command can be applied to the tool. All movement commands after commanding the maximum cutting position are set to the downward side of the cam.

〔Example〕

Hereinafter, the present invention will be described in detail based on the accompanying drawings.

In FIG. 1, 1 is a main shaft, which is rotatably supported by a headstock 2. In FIG. The main shaft 1 includes a chuck (not shown) that penetrates and guides a material such as a bar (not shown) in the Z direction shown in the drawing and grips it.

A pulley 3 is provided on the main shaft 1, and driving force is transmitted to the main shaft 1 by a belt 5 stretched between it and a pulley 4A of a motor 4. Note that as the main shaft 1 moves in the Z direction, the belt 5 can slide on the pulley 4A of the motor 4 in the same direction.

A bracket 6 containing a ball nut 7 is attached to the headstock 2, and a ball screw 8 is screwed through the ball nut 7. This ball screw 8 has bearings 9 at both ends,
10, and is connected to the shaft of a servo motor 11 at one end. The servo motor 11 rotates based on a command from a control device, which will be described later, in response to a signal related to Z-direction feed in a setting program, thereby moving the ball screw 8, that is, the headstock 2, in two directions.

Further, a tension spring 12 is stretched between one end of the headstock 2 and a fixed part, and is applied with a force of returning to the left in the figure.

At the forward (right) position of the main shaft 1 in the Z direction, a pusher 13 is provided on an immovable frame 14 for rotatably and slidably guiding the material in two directions. The frame 14 includes
A plurality of tool rests 16 each having a cutter 15 are pushed 1
3 and are provided radially so as to be movable in a plane perpendicular to the Z direction. However, only one tool rest 16 is shown in the figure. A link 17 for driving the tool rest is in contact with the end (the upper end in the case of the one shown) of each tool rest 16, and the link 17 is driven by a cam 20 via a rod 18 and a cam follower 19. Ru. The cam 20 is provided on a cam shaft 24 that is rotatably supported by bearings 21, 22 and 23. This cam shaft 24 has respective cams (only the cam 20 is shown) corresponding to each of the above-mentioned tool rests.
are installed at mounting angles according to the program, and each turret is driven by a mechanism consisting of the same links, rondos, and cam followers.

Each of the above cams is formed as a standard cam with the same shape and dimensions, and as shown in Figure 2, the minimum rising angle γ for approaching the start of machining on the upward side, and the maximum angle for machining to the maximum cutting position. has an equal lift angle β,
On the downhill side, symmetrical to this is the equal lift angle β and the lower I! s has a minimum angle γ.

Note that the above-mentioned cam does not necessarily have to have a symmetrical shape as shown in the drawings, and even if it is asymmetrical, it can be used as a standard cam for each cam.

The camshaft 24 is rotatably driven via a worm 26 and a worm wheel 27 by an X-axis servo motor 25 which rotates based on a command from a control device, which will be described later, in response to a signal related to X-direction feed of a set program.

Also, on the right end of the camshaft 24, a cam 2 for a lever 27 that pushes out the attachment spindle 26 in two axial directions is provided.
8 is also provided. Furthermore, a sensor 29 is provided at the left end of the camshaft 24 to detect the origin of one revolution of the camshaft 24.

In addition, the chuck of the main shaft 1 is attached to the cam shaft 24.
A cam 31 is also provided for operating a lever 30 that opens and closes every rotation.

The servo motor 11 for controlling the Z-axis direction and the servo motor 25 for controlling the camshaft are connected to a control device 40, thereby receiving rotation control. The control device 40 includes the mounting angle of each cam, the height of the cam, the rising angle,
The descending angle is set as a parameter, and data regarding these parameters will not change even if the machining program, that is, the product dimensions change.Furthermore, the control device 40 has the machining program for each product as an X-direction and two-direction command. It is now entered as .

The control device separates the input machining program into an X-direction command and an X-direction command, and uses the former to control the servo motor 11.
The latter is converted into a rotation angle of the cam, and the servo motors 25 are each controlled to rotate based on the command. To convert this into a rotation angle, read the machining start position and maximum cutting position in the X direction of the cutter selected from the input machining program, and calculate the distance between the machining start position and maximum cutting position using the cam. This is done by calculating the rotation angle of the camshaft from the ascending angle and descending angle of the cam, which are proportionally distributed in accordance with the height. At this time, the angle is calculated so that all commands after the blade passes through the maximum cutting position are on the downward side of the cam. Thus, since the Z-direction program is separated as described above, only the X-direction program is executed on the camshaft by controlling the angle of the standard cam.

Next, in the apparatus of this embodiment as described above, processing is performed as follows.

The servo motors 11 and 25 operate independently according to a program set at the time when Z-axis and X-axis feed is required, respectively, based on commands from the control device 40.

First, the headstock 2 is moved to a predetermined position in the Z direction by the servo motor 11, and the workpiece is brought to the processing start position.

The servo motor 11 stops at this point.

Next, the servo motor 25 rotates the camshaft 24 according to the command from the control device 40 according to the angle command obtained by converting the amount of movement of the cutter in the X direction, and one cam 20
A predetermined tool rest 16 is selected. Since the amount of movement of the blade 15 in the X direction (the depth of cut it) is converted into the rotation angle of the cam by the control device 40 as described above, the camshaft 24 is rotated by the servo motor 25 as an angle program. Then, the cut with the cutter 15 is performed. When the cut is made by a predetermined amount, the camshaft 24 stops, the servo motor 11 rotates again, the main shaft l moves in the Z direction, the blade is fed in the Z direction, and the material is processed in the same direction. When a predetermined amount of machining is completed in the Z direction, the servo motor 11 stops.

Next, when selecting another cutter, the servo motor 25
The camshaft 24 rotates, and the appropriate cam moves the corresponding tool rest.

Normally, tool compensation is performed in this type of lathe to compensate for tool wear, but it is clear that at the top of the cam, it is physically impossible to perform tool compensation in the direction of increasing the depth of cut. Therefore, in the present invention, as shown in Figs. 3 and 4 (by creating a machining program that causes the cutter to make an extra cut of d into a part unrelated to the shape of the product, By setting the position at an angle away from the highest point of the cam, it is possible to make the value d the maximum and perform tool correction in the product shape within that range.

C Effects of the Invention] As described above, in the present invention, the machining program is executed by the servo motors in the Z direction and the X direction, and
Since we decided to convert the direction control into cam angles, machining programs can be easily created while maintaining the high reliability and high productivity that are the advantages of the cam type, and the work efficiency is extremely improved. This has the effect of drastically reducing production errors.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a device for an embodiment of the present invention, FIG. 2 is a diagram showing an example of a cam used in the device shown in FIG. 1, and FIGS. 3 and 4 are similar to those shown in FIG. 1. Figures 5, 7, and 8 are diagrams showing the amount of tool correction in the device, and Figures 6 (A) to (6) are diagrams showing the tool movement process when machining is performed with a conventional cam type. D) is a diagram showing how the cam moves in the steps of FIGS. 5, 7, and 8. 1... Main shaft 11... Servo mechanism (servo motor) 1
3...Push 16...Turret 20...Cam 24...Cam shaft 25... ... Servo mechanism (servo motor) 4
0......Control device

Claims (1)

[Scope of Claims] A main shaft that can rotate and rotate a material that is rotatably and slidably guided by a push and move in the direction of the Z-axis, which is the axis thereof, and a main shaft that moves toward the main shaft in a plane perpendicular to the Z-axis. A plurality of turrets extending in the X direction so that a predetermined one can be selected, a servo mechanism that moves the main axis in the Z direction according to a setting program, and a turret corresponding to each of the plurality of turrets. A machining method using a moving spindle lathe that is equipped with a camshaft that is provided with a cam for selection and cutting of the blade and is rotated by a servo mechanism under a setting program, and a control device that controls the servo mechanism and the camshaft. Then, the mounting angle, cam height, ascending angle, and descending angle of each cam are stored in advance in the control device, and then the machining program for product machining is input, and then each of the above machining programs is inputted into the control device. The machining start position and maximum cutting position in the X direction of the blade corresponding to the cam are read, the blade is selected by rotating the cam shaft by the mounting angle of the cam corresponding to the blade, and the selected blade is The distance between the machining start position and the maximum depth of cut position is made to correspond to the cam height, and the above-mentioned blade movement program in the X direction is converted into a camshaft rotation program by angle using the cam's ascending angle and descending angle. A machining method using a main spindle moving type automatic lathe, in which the rotation of the camshaft is controlled by the rotation of the camshaft, and the movement of the main spindle in the Z direction is controlled by a servo mechanism according to a set program.