JPS6238091B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a cutting tool that reciprocates in a direction parallel to the axis of a workpiece, a numerically controlled motor that rotatably drives a headstock spindle on which a workpiece is attached, and a numerically controlled motor that reversibly drives the mount of the tooling tool. A machine dedicated to processing roots rotors, which is equipped with an X numerically controlled motor that moves in the front-back direction perpendicular to the reciprocating line of movement, and a Z numerically controlled motor that moves the mounting base in the up and down direction that is perpendicular to the back-and-forth direction. The present invention relates to a processing method exclusively for roots rotors, in which a roots rotor with two to several leaves is precisely processed by a machine.

A roots rotor with two or several leaves is created by creating two or several heads of convex circular curves at equal angular intervals and valleys forming concave arc curves between the heads with a cutting tool, and then casing several of the rotors. Each head is fitted into the inner surface of the casing with a clearance of about 0.02 to 0.05mm, making it almost in contact with the inner surface of the casing, and the rotors are also rotated in the meshing direction by a timing gear with the above-mentioned clearance. A high degree of precision is required to create this roots rotor using a special machine tool, but since the cross-sectional shape is non-circular, it cannot be cut using normal cutting methods, and special cutting methods are required. Requires technique.
The present invention relates to a special processing method specific to such roots rotors, and is a workpiece for creating a two- to several-leaf roots rotor whose circumferential surface connects equiangularly spaced heads 32 made of convex arc wires and valleys 33 made of concave arc wires. Regarding W, a convex arc locus 52 whose radius is a straight line connecting the convex arc curve center a of the head 32 with the axis 41 of the workpiece
, the center b of the concave arc line of the trough 33 and the axis 4 of the workpiece
1, and a concave arc locus 53 whose radius is the straight line connecting 1.
The rotation of the X numerical motor 22 and the Z numerical motor is controlled by the program of the moon-shaped locus 51 drawn by aligning the straight line connecting each center a, b and the axis 41 with the axis 41, and connecting the intersection points on both sides. At the same time, the numerically controlled motor 21 is synchronously rotated, and the workpiece W is moved in the opposite direction alternately when cutting according to the convex arc trajectory 52 program and when cutting according to the concave arc trajectory 53 program. It is characterized by rotation.

A machine tool dedicated to Roots rotor machining suitable for carrying out the method of the present invention will be described with reference to FIGS. 1-3.

In the figure, reference numeral 1 denotes an installation board, in which a column 3 is provided on a frame 2 erected on the rear side, a ram 4 is provided on the column, and a slide 5 that reciprocates in the left and right direction is attached to the ram 4. Attach the cutting tool 7 facing the front to the cutting tool stand 6 of the slide 5. Part-time job stand 6 is y
The movement stroke is adjusted by a stroke adjustment shaft 8 shown in FIGS. 1 and 2. The speed of the tool table 6 in the y-axis direction is determined by a variable rotation speed motor (not shown) that reciprocates the slide 5, and the rotation speed of the motor is adjusted by rotating an adjustment handle 9.

There is a lifting screw 11 on the front of the frame 2 of the installation stand 1.
and is supported by the lifting guide 1 of the frame 2.
A lifting platform 12 that moves up and down guided by Stand 14 and tailstock 1
6 are installed in correspondence with each other, and the workpiece W is attached to the chuck 15 of the headstock spindle and the tailstock 16.

Reference numeral 21 denotes a numerically controlled motor that controls the reversible rotation of the main shaft (chuck 15) of the headstock 14, and the workpiece W is reversibly rotated by the motor 21. Reference numeral 22 denotes an X numerically controlled motor that moves the table 13 and the headstock 14 in the x direction, and the workpiece W is moved in the back and forth direction x by the motor 22. Reference numeral 23 is a Z numerically controlled motor that moves the lifting platform 12 up and down, and moves the work W in the up and down direction z together with the headstock 14, table 13, etc.

FIG. 4 shows an example of a roots rotor 31 processed by the method of the present invention, and the figure shows a three-lobed rotor.
The rotor 31 is created from a workpiece W, and protrudes three convex arcuate heads 32 at equal angular intervals around an axis 41.
An imaginary circle 42 connected by a trough 33 forming a concave arc curve between the two and drawn around an axis 41;
Determining a convex arc curve of the head 32 with the center a being the intersection with the radius line 44 passing through the center of the head 32,
A concave arc curve is determined with the intersection point of a virtual circle 43 concentric with the virtual circle 42 and a radius line 45 passing through the center of the valley portion 33 as the center b. The virtual circles 42 and 43 have different radius values depending on the number of heads, etc., but the center a is the center of the head convex arc curve, and the center b is the center of the trough 3.
The principle of the center of the concave arc curve in No. 3 is the same.
The radius value L of the convex arc curve and the radius value L' of the concave arc curve show the relationship L=L'. Of course, L' may be increased very slightly.

The numbers for Figures 4 and 5 ~ indicate the outer diameter.
76.8, the required dimensions of a three-lobed roots rotor in which the radius of the virtual circle 43 is 25 and the radius of the virtual circle 43 is 28.5, and the unit is mm.

The method of the present invention is carried out by moving the cutting tool 7 in the left-right direction y at an arbitrary height. Reversible rotation of the workpiece W about the shaft 41 is performed by the numerically controlled motor 21 of the headstock main shaft.

Movement of the shaft 41 of the workpiece W in the back-and-forth direction x perpendicular to the reciprocating direction y of the cutting tool 7 is performed by rotating the X numerical motor 22 that moves the headstock 14 in the back-and-forth direction x, and is perpendicular to the front-back direction x of the shaft 41. vertical direction z
The movement is performed by the rotation of the Z numerical motor 23 that moves the headstock 14 in the vertical direction z, and the roots rotor 3
The method of the present invention involves recording the program of the crescent-shaped locus 51 in FIG. Performed by command signal. The program for the crescent-shaped locus 51 is as shown in FIGS. 4 and 5. As illustrated in FIG.
The program of the crescent-shaped locus 51 is drawn by matching the intersection points of both sides, and the program of the crescent-shaped locus 51 rises in the z direction and connects the center a of the convex arc locus 53, the center b of the concave arc locus 53, and the workpiece W. The data are recorded on the computer so that the axis 41 of In this recording, the upper and lower intersections of the convex arc locus 52 and the concave arc locus 53 are defined as the limits of the relative movement of the cutting tool 7. A crescent-shaped locus 51 for the cutting tool 7 is located between the center a of the convex arc curve of the head 32 and the axis 41 of the workpiece W.
and the cutting tool 7 are in a straight line in the front-rear direction x as shown in FIG. This is determined by giving the opportunity to form a straight line in the front and rear directions as shown. Axis 41 of workpiece W
As described above, the cutting tool 7 is rotated by the numerically controlled motor 21 to bring the cutting tool 7 into contact with the head 32 or the trough 33. The program for the crescent-shaped locus 51 described above may be slightly modified in order to make the cutting smoother or easier to assemble when actually cutting the roots rotor. Correction is made using the crescent-shaped locus 51 in FIG. 6 as a standard, and the crescent-shaped locus 5 illustrated in FIG.
There is no need to change the principle of the Roots rotor dedicated processing method, which is performed by creating a program according to 1.

The program of the crescent-shaped locus 51 is the same for the two-lobed Roots rotor.

The cutting tool 7 has a convex arc curve that almost matches the concave arc curve at the center of the valley portion 33, as shown in FIG.

To explain the method of this embodiment in detail, the workpiece W having a machining allowance of the roots rotor 31 illustrated in FIG. The axis 41 of
2. The drive control of the Z numerically controlled motor 23 is performed according to the program of the crescent-shaped locus 51, and the sequence shown in FIG. 5 is repeated. The numerically controlled motor 21 rotates the workpiece W on the concave arc locus 53 of the crescent-shaped locus 51 in the opposite direction to the direction during cutting on the convex arc locus 52.

FIG. 5 shows a mode in which the top of the head 32 of the roots rotor 31 is cut, and in this case, the motor control is performed for the cutting tool 7 so that the axis 41 of the workpiece W coincides with the center point of the convex arc locus 52 that is farthest on the horizontal line. administer. FIG. 5 shows a mode in which the side part of the head 32 is cut, in which case the shaft 41 is moved along the moon-shaped trajectory 51.
The convex arc locus 52 approaches the concave arc locus 53 one after another. Next, as shown in FIG. 5, the shaft 41 moves to the intersection of the convex arc locus 52 and the concave arc locus 53 to finish cutting the head 32, the shaft 41 moves on the concave arc locus 53, and the numerically controlled motor 21 moves to the intersection of the convex arc locus 52 and the concave arc locus 53. Rotate in the opposite direction as described above. FIG. 5 shows a state in which the center of the valley portion 33 is cut by the cutting tool 7, and at this time the shaft 41 approaches the cutting tool 7 closest. The cutting of the valley part 33 is thus completed, and the shaft 4 is cut as shown in FIG.
1 reaches the intersection of the convex arc locus 52 and the concave arc locus 53, the workpiece W is rotated forward again by the numerically controlled motor 21, and the shaft 41 moves the convex arc locus 52 to the fifth point.
Moving as shown in the figures, the next head 32 is cut by the cutting tool 7, and cutting from FIG.

In FIG. 5, the axis 41 of the workpiece W,
The center a of the head 32 or the center b of the valley 33,
The cutting tool 7 forms a horizontal straight line in the front-rear direction x.

In the method of the present invention, the W axis 41 of the workpiece is driven based on the reciprocating direction y of the cutting tool 7 in accordance with a program based on the crescent-shaped locus 51 of the X numerically controlled motor 22 and the Z numerically controlled motor 23. W
The roots rotor 31 illustrated in FIG. 4 is sequentially cut and formed from one end to the other by repeating the movement of the shaft 41. By combining the generated program controls, it is possible to precisely process a roots rotor with a unique configuration in which the number of leaves changes in various ways.

[Brief explanation of the drawing]

Fig. 1 is a side view of a machine tool adapted to implement the present invention, Fig. 2 is a plan view thereof, Fig. 3 is a front view thereof, Fig. 4 is a perspective view illustrating a roots rotor, and Figs. FIG. 6, which is a front view illustrating the implementation of the invention method in sequence, is an explanatory diagram of a crescent-shaped locus 51. 7 → Bit, 15 → Headstock, W → Work, 21
→ Numerical control motor, 22 → x Numerical control motor, 2
3 → z numerical control motor, 31 → Roots rotor, 3
2 → head, 33 → valley, 41 → axis, 51 → crescent-shaped locus, 52 → convex arc locus, 53 → concave arc locus.

Claims (1)

[Scope of Claims] 1. A cutting tool that reciprocates in the direction y parallel to the axis 41 of the workpiece W, a numerically controlled motor 21 that reversibly rotates the headstock main shaft on which the workpiece W is attached, and a headstock that rotates in the direction of movement of the tooling tool. an X numerical motor 2 that moves in a front-rear direction x perpendicular to the moving direction y with reference to y;
2, and a Z numerically controlled motor 23 that moves the headstock in the vertical direction z perpendicular to the longitudinal direction
For a workpiece W that creates a two- to several-lobed roots rotor connecting valleys 33 made up of concave arc lines, a convex arc locus 52 whose radius is a straight line connecting the convex arc curve center a of the head 32 and the axis 41 of the workpiece. , Tanibe 3
A concave arc locus 53 whose radius is a straight line connecting the center b of the concave arc line of No. 3 and the axis 41 of the workpiece is defined by each center a,
The rotation of the X numerical motor 22 and the Z numerical motor is controlled by the program of the crescent-shaped locus 51 drawn by aligning the straight line connecting b and the axis 41 and the axis 41, and connecting the intersection points on both sides, and the workpiece is placed at the tip of the cutting tool. W is brought into contact, and at the same time, the numerically controlled motor 21 is rotated synchronously,
A processing method exclusively for roots rotors, characterized in that the workpiece W is alternately rotated in opposite directions during cutting according to the program of the convex arc locus 52 and when cutting according to the program of the concave arc locus 53.