JPH0636701U - Cutting equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] In turning of high hardness members, it is possible to process in heavy cutting areas without reducing the tool life. [Structure] The work 8 rotates around the axis at a peripheral speed Vw,
The two cutting tools 5 rotate around the axis in the same direction as the work 8 at a peripheral speed Vt higher than the peripheral speed Vw of the work 8. The three cutting tools 5 are arranged on the same circumference at intervals of 120 degrees, and are held by the jig 3 so as to be movable in the radial direction. Positioning control of these cutting tools 5 is performed in synchronization with the radial direction by a positioning control mechanism.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cutting device for turning a high hardness member such as hardened steel using a plurality of cutting tools.

[0002]

[Prior art]

 For example, so-called hardened steel cutting is known in which steel members are hardened and then turned for the purpose of finishing with high accuracy while avoiding heat treatment deformation of thin-walled products. For cutting, a single cutting tool was used, and the peripheral speed was 100 m / min and the feed rate was 0. It is generally applied in a light to medium cutting region of 1 mm / rev and a diameter cut of about 0.5 mm.

[0003]

[Problems to be solved by the device]

 Conventionally, in the case of hardened steel cutting, machining in the heavy cutting region (cutting under conditions of high cutting speed and high feed / deep cutting) has not been performed because the hardness of the work is high and the cutting speed that affects the tool life When the cutting tool life is extremely shortened in the heavy cutting area due to the significant influence of the tool, the machining efficiency decreases due to the increased frequency of tool replacement, or the machining accuracy decreases due to machining with a worn tool. Is a concern.

The object of the present invention is to improve the machining efficiency by turning in a heavy cutting area without deteriorating the tool life in the turning of a high hardness member such as hardened steel. It is in.

[0005]

[Means for Solving the Problems]

 The cutting device of the present invention includes a plurality of cutting tools arranged on the same circumference, a jig for movably holding these cutting tools, and a radial direction position of the cutting tools held by the jig. A positioning control mechanism for controlling the cutting tool is used to position the cutting tool in the radial direction while rotating in the same direction as the rotation direction of the work and at a higher rotation speed than the work.

[0006]

[Action]

 Actually cutting each cutting tool against the peripheral speed of the work by positioning the cutting tools in the radial direction and rotating them in the same direction as the work rotation direction and at a higher rotation speed than the work. The speed (the speed at which each cutting tool actually cuts the work) is relatively reduced, and the burden on each cutting tool during machining is reduced.

[0007]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an overall configuration of a cutting device according to this embodiment. This cutting device includes a cylindrical housing 1 that can move back and forth in the axial direction, a cylindrical main shaft 2 that is rotatably supported by a pair of bearings 1b on the inner diameter of the housing 1, and a jig that is connected to the tip of the main shaft 2. The tool 3, the three cutting tools 5 held by the jig 3, and the positioning control mechanism 6 connected to the jig 3 are main components. A chuck 7 that is rotatable and axially movable (not necessarily axially movable) is arranged facing the jig 3. For example, the shaft-shaped work 8 is held by the chuck 7.

The spindle 2 is rotationally driven by a motor 10 connected via a belt 9. When the spindle 2 rotates, the jig 3 connected to it rotates, and the cutting tool 5 rotates.

The positioning control mechanism 6 axially drives the pair of ball splines 61 fixed to the inner diameter of the main shaft 2, the ball spline shaft 62 and the ball spline shaft 62 axially guided by the ball splines 61. The ball screw 63 and the servo motor 64 are main components. The tip end portion of the ball spline shaft 62 is connected to the jig 3, and the rear end portion thereof is connected to the ball nut 63a of the ball screw 63 via a pair of bearings 65 and a coupling 66. Further, the coupling 66 and the ball nut 63a are integrally connected, and these can be moved only in the axial direction by being guided by the guide member 67.

When the servo motor 64 rotates, the screw shaft 63b rotates, and the ball nut 63a screwed to the screw shaft 63b and the coupling 66 integrally move in the axial direction. Then, the ball spline shaft 62 connected to the coupling 66 slides in the axial direction. The sliding movement of the ball spline shaft 62 is position-controlled by the servo motor 64.

FIG. 2 shows the jig 3. In this embodiment, a commercially available three-jaw chuck (for example, HO27 manufactured by Towa Kogyo Co., Ltd.) is used as the jig 3. The structure will be briefly described. In this jig 3, a master jaw 32 is mounted in a radial notch 31a provided in an end surface of a main body 31 so as to be movable in a radial direction, and a taper provided in the master jaw 32 is provided. The surface 32a is brought into contact with the tapered surface 33a of the wedge plunger 33 which is slidable in the axial direction. When the wedge plunger 33 is slid in the axial direction, the master jaw 32 is moved in the radial direction. ing. The master jaws 32 are attached to the main body 31 at three circumferentially equidistant positions, and a soft jaw 36 is fixed to each of these three master jaws 32. The slide movement of the wedge plunger 33 is performed by the draw screw 34. The draw screw 34 is abutted against the end surface of the wedge plunger 33, and is retained by the retainer 35. The retainer 35 is fixed to the end surface of the wedge plunger 33 by bolts.

In this embodiment, the cutting tools 5 are attached to the three soft jaws 36, and the ball spline shaft 62 is connected to the draw screw 34. For example, when the ball spline shaft 62 is slid to the left in the figure, the wedge plunger 33 slides to the left via the drop crow 34 and the retainer 35, and the master jaw 32 moves to the inner diameter direction. Conversely, when the ball spline shaft 62 is slid to the right in the figure, the master jaw 32 moves in the outer diameter direction. Since the radial position of the master jaw 32 is determined by the axial position of the wedge plunger 33, eventually, the radial position of the master jaw 32 can be controlled by controlling the positioning of the ball spline shaft 62 in the axial direction. . This makes it possible to position and move the three cutting tools 5 in synchronism with each other in the radial direction.

FIG. 3 is a diagram showing a processed state of the work 8. The work 8 is held by the chuck 7 shown in FIG. 1 and is rotated at a peripheral speed Vw (m / min) around the axis, and the three cutting tools 5 are held by the jig 3, and the circumference of the work 8 is around the axis. The workpiece 8 rotates in the same direction as the peripheral speed Vt (m / min), which is higher than the speed Vw. The three cutting tools 5 are arranged on the same circumference at intervals of 120 degrees, and are fixed to the soft jaws 36 of the jig 3 shown in FIG. Positioning control of these cutting tools 5 is performed in the radial direction in synchronization with each other by the positioning control mechanism 6 in the manner described above. The axial feed can be given by positioning and moving the cutting tool 5 in the axial direction, but as described above, in this embodiment, the housing 1 (see FIG. 1) can be moved back and forth in the axial direction. Is moved in the axial direction by an appropriate feed control mechanism (not shown) to feed the cutting tool 5 in the axial direction at the feed speed F (mm / rev: rev is based on the rotation of the work 8). I am doing it. In the following, when the work peripheral speed Vw = 300 (m / min), the tool peripheral speed Vt = 400 (m / min), the feed speed F = 0.25 (mm / rev), and the diameter cut d = 1.0 mm are set. I will explain.

Since the work 8 and the cutting tool 5 rotate in the same direction, the cutting speed (actual cutting speed: Vd) at which the cutting tool 5 actually processes the work 8 is the peripheral speed Vt and the peripheral speed V. The peripheral speed difference from w is 100 m / min. The actual cutting speed Vd = 100 m / min is the same as the cutting speed 100 m / min in the conventional hardened steel cutting described above. However, the feed rate F of the cutting tool 5 is 2.5 times, and the depth of cut d is doubled.

For example, focusing on one cutting tool 5 (referred to as 51) in FIG. 3, the peripheral speed difference between the cutting tool 51 and the work 8 is 1/3 rotation in terms of rotation speed (that is, Then, the cutting tool 51 makes 4/3 rotations with respect to one rotation of the work 8.), and when the work 8 makes one rotation, the cutting tool 51 rotates relative to the work 8 by 1/3 rotation. At this time, the relative position of the cutting tool 51 with respect to the workpiece 8 is exactly the position of the cutting tool 52 adjacent in the rotational direction, which is 120 degrees apart in FIG. In this manner, the cutting tool 51 rotates relative to the work 8 by 1/3 rotation, so that the region R1 corresponding to 1/3 circumference of the work 8 is processed. At this time, the actual cutting speed Vd of the cutting tool 51 is 100 m / min, and the set feed speed is F = 0.25 mm / rev. Similarly, since the cutting tool 52 and the cutting tool 53 process the regions R2 and R3 for 1/3 turn respectively, eventually, the entire circumference of the work 8 is processed for one rotation of the work 8. Therefore, the same result as that obtained by machining with a single cutting tool (only rotating the work) at a cutting speed of 100 m / min and a feed speed of 0.25 mm 2 / rev is obtained. However, it is impossible to achieve the machining efficiency obtained by the machining method using the cutting device of the present embodiment by the conventional machining method (method that uses only a single cutting tool and rotates only the workpiece). Is. The reason is shown below.

Although three cutting tools are used in this embodiment, if it is assumed that 900 workpieces could be machined by the machining method of this embodiment in a total machining time of 600 minutes, the same machining is performed. It will be examined whether the efficiency can be achieved by the conventional processing method (the number of cutting tools is 3, and these are sequentially replaced). Since both cutting methods use three cutting tools, the cutting distance per cutting tool is 300 in terms of the number of workpieces. However, the time required for one cutting tool to perform cutting is 600 minutes, which is the same as the total processing time, in the processing method of the present embodiment, since three cutting tools are used for processing at the same time. Since three cutting tools are sequentially replaced, 600/3 = 200 minutes. Therefore, if it is attempted to achieve the same machining efficiency with the conventional machining method, it is necessary to perform machining at a cutting speed (300 / min) that is three times that of the machining method of this embodiment, and the tool life is extremely reduced. As a result, it becomes practically impossible to secure a cutting distance of 300 workpieces per cutting tool. That is, it is difficult to achieve the same processing efficiency as the processing method of this embodiment.

As described above, the cutting device according to the present embodiment sets the actual cutting speed Vd of each cutting tool 5 to the same level as the cutting speed in the conventional light to medium cutting region, thereby making the tool life according to the cutting speed. This eliminates the cause of the decrease in the tool life. Therefore, without decreasing the tool life, the heavy cutting area such as the work peripheral speed Vw = 300 / min, the feed speed F = 0.25 mm / rev, and the diameter cut d = 1.0 mm. Can be processed. As a result, it is possible to significantly improve the machining efficiency in cutting hardened steel compared to conventional methods. In this embodiment, the three cutting tools 5 are arranged at equal intervals on the circumference, but this is done by matching the set feed speed with the actual feed speed and using a single cutting tool. This is to obtain the same surface roughness as. That is, the difference in peripheral speed between the cutting tool 5 and the work 8 is 1/3 rotation, and by arranging the three cutting tools 5 at equal intervals on the circumference, one rotation of the work 8 makes a full rotation. Since it is machined, it has the same surface roughness as a single cutting tool. Therefore, for example, if the peripheral speed difference between the cutting tool 5 and the work 8 is 1/4 rotation, 4 cutting tools are arranged at equal intervals on the circumference, and if it is 1/5 rotation, 5 cutting tools 5 are used. The same effect can be obtained by arranging. However, if the number of cutting tools 5 arranged is increased, the actual cutting distance of each cutting tool 5 is reduced, and the tool life is further improved. In other words, more heavy cutting is possible. The above relationship can be generalized by the following equation.

N = Vw / (Vt-Vw) N: number of cutting tools arranged Vw: peripheral speed of work Vt: peripheral speed of cutting tool

The above description is for the case where the outer diameter of the shaft-shaped work 8 is machined. In this case, the radial position of the cutting tool 5 is kept constant (that is, the cutting depth is kept constant). Machining is performed by giving a constant feed in the axial direction, but by performing machining while interpolating the radial position and axial position of the cutting tool 5 with the positioning control mechanism 6 and an appropriate feed control mechanism, It is possible to freely process curved surfaces such as running surfaces and end surfaces.

[0021]

[Effect of device]

 As described above, according to the present invention, a plurality of cutting tools arranged on the same circumference are held so as to be movable in the radial direction, and while these are positioned in the radial direction, they are in the same direction as the rotation direction of the workpiece. In addition, the actual cutting speed of each cutting tool relative to the peripheral speed of the work is reduced because it is rotated at a higher rotation speed than the work. By reducing the load, it is possible to process a high hardness member such as hardened steel in the heavy cutting region without lowering the tool life. Also, by performing machining while performing interpolation control of the radial position and axial position of the cutting tool, the outer diameter of the shaft-shaped member, the inner and outer diameters of the ring-shaped member, as well as the curved surface and end surface can be freely processed. be able to.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing a jig in FIG.

FIG. 3 is a view showing a processing state of a work.

[Explanation of symbols]

 3 jig 5 cutting tool 6 positioning control mechanism 8 work

Claims (1)

[Scope of utility model registration request] 1. A plurality of cutting tools arranged on the same circumference, a jig for movably holding these cutting tools, and a radial position of the cutting tools held by the jig are controlled. A cutting device, comprising: a positioning control mechanism, wherein the cutting tool is rotated in the same direction as the rotation direction of the work and at a higher rotational speed than the work while positioning the cutting tool in the radial direction.