JPH01222801A - Lathe, tool rest of lathe and machining method by lathe - Google Patents

Abstract

PURPOSE:To reduce the quantity of abrasion of a tool caused by turning and improve machining efficiency and machining accuracy by rotating a tool having a circular arc shaped tool bit centering around the circular arc during cutting and changing the position of the tool bit which is brought into contact with a workpiece. CONSTITUTION:The captioned lathe has a headstock 2 and a tail stock 3 for supporting both ends of a workpiece 1, and the head stock 2 houses a main motor for driving the workpiece 1. A tool rest 6 for supporting a cutting tool 5 is provided on a carriage 4. The cutting tool 5 has a circular arc shaped tool bit and the tool rest 6 is formed so that the cutting tool is rotated centering around the point which agrees with the center of the curvature radius of the tool bit, while having a rotation driving motor 30 for rotating the tool 5. The tool 5 is rotated centering around the point which nearly agrees with the curvature center of the tool bit configuration thereof while rotating the workpiece 1, to carry out the relative movement in the direction of the rotation axis of the workpiece 1 thereto to obtain an excellent effect.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a lathe that performs machining by moving a tool relative to a workpiece, a tool stand for the lathe, and a machining method using the lathe. .

[Conventional technology]

In general, in conventional lathes, the cutting edge of a tool is fixed to a tool stand and touches the rotating workpiece, and the tool is moved in the direction of the rotational axis of the workpiece. Processing is performed by moving it. That is, the same portion of the cutting edge of the tool is always in contact with the workpiece during machining.

[Problem to be solved by the invention]

In general, when machining with a lathe, the wear of the tool cutting edge is significant.
Particularly, when machining is always carried out on the same part of the cutting edge of the tool, as in the conventional lathe described above, wear increases in proportion to time, resulting in a very short tool life. Particularly, when processing a highly hard workpiece (for example, a rolling roll, etc.), the wear rate is high, and such tool wear deteriorates the processing accuracy. Furthermore, even if the tool is replaced during turning, a difference in joint level will be created in the workpiece at the replacement location, which inevitably deteriorates machining accuracy.

Conventionally, when machining the workpiece, six methods have been adopted: using a lathe only in the rough machining stage, and grinding with a grinding tool such as a grindstone in the finishing machining stage. However, in this case, since both a turning machine and a grinding machine must be prepared, a large amount of equipment costs are required, resulting in high costs.

Furthermore, in the above-mentioned grinding process, compared to turning process using a lathe, it is not possible to obtain a large depth of cut at once, so the process has to be performed while repeatedly moving the tool back and forth, resulting in a long process time. Is required. In addition, the grinding wheel must be replaced periodically depending on the required finished surface roughness and the material of the workpiece, and such grinding tools are relatively heavy and inconvenient to handle.
Processing efficiency is poor. Furthermore, a large amount of grinding fluid is required, cleaning and processing of the grinding wheel powder is troublesome, and equipment management is difficult.

In view of these circumstances, the present invention provides a lathe, a tool stand thereof, and a machining method using the lathe, which can improve machining efficiency and machining accuracy by reducing tool wear caused by turning. The purpose is to

[Means to solve the problem]

The present invention provides a tool rest for supporting a tool, a workpiece rotation driving means for supporting and rotating a workpiece, and a workpiece rotation driving means for supporting and rotating a workpiece, and a tool stand for supporting a workpiece and a workpiece rotation driving means for supporting and rotating a workpiece, and In a lathe equipped with a feeding means for relatively moving a tool rest, the cutting edge of the tool is formed into an arc shape, and the tool rest is arranged so that the tool can rotate around a point that substantially coincides with the center of curvature of the cutting edge shape. The tool rotation driving means for rotating the tool is provided.

Then, the workpiece is rotated, and while the tool is in contact with the workpiece, a tool having an arc-shaped cutting edge is rotated around a point that approximately coincides with the center of curvature of the cutting edge shape, and the tool is placed against the workpiece. Excellent effects can be obtained by performing processing to relatively move the shaft in the direction of its rotation axis.

Furthermore, it is more preferable to rotate the tool so that the entire area of the cutting edge of the tool comes into contact with the workpiece while the tool rest moves over the entire area of the workpiece.

(Function) According to the above configuration, as the tool rotates during turning, the part of the cutting edge that contacts the workpiece changes, compared to a structure in which the same part of the cutting edge always contacts the workpiece. , the tool life is significantly extended.Furthermore, by making the entire area of the tool tip contact the workpiece while the tool carriage is moving across the entire area of the workpiece, the tool life can be significantly extended. It can be used evenly over the entire range, preventing uneven wear.

(Embodiment) FIG. 1 is a diagram showing the overall configuration of a lathe in an embodiment of the present invention. This lathe is equipped with a headstock 2 and a tailstock 3 that support both ends of a substantially cylindrical workpiece (workpiece) 1, and the headstock 2 is configured to rotate the workpiece 1 at high speed. It has a built-in main motor. A carriage 4 configured to be movable in the direction of the rotational axis of the workpiece 1 is installed on the side of the workpiece 1 in this supported state, and a cutting tool 5 is placed on the carriage 4.
A tool stand 6 is provided to support the.

The structures of the carriage 4 and the tool stand 6 will be explained based on FIGS. 2 to 7. As shown in FIG. 2, two ball screw nuts 7 are fixed in series at the bottom of the carriage 4.
is screwed into a ball screw 8 rotatably supported on the lathe main body side. This ball screw 8 is connected via a reduction gear box 9 to a vertical feed drive motor 10 installed in the lathe body, and the ball screw 8 is rotationally driven by this vertical feed drive motor 10. , the carriage 4 is integrally driven reciprocatingly (vertically fed) in the above direction with the ball screw nut 7 meshing therewith.

As shown in FIG. 3, a loss slide 11 is fixed to the lower part of the tool stand 6, and this cross slide 11 is guided in a horizontal direction toward and away from the workpiece 1. It is mounted on the carriage 4 as shown in FIG.

A ball screw nut 13 similar to the ball screw nut 7 described above is provided inside this cross slide 11, and a ball screw 12 screwed into this ball screw nut 13 is supported horizontally within the carriage 4. In this state, it is connected to a lateral feed drive motor (feeding means) 15 via a reduction gear box 14. When the ball screw 12 is rotationally driven by this lateral feed driving motor 15, the tool stand 6 is driven (transversely fed) in the above direction together with the ball screw nut 13 that meshes with the ball screw 12, and the cutting tool 5 is adapted to approach and separate from the workpiece 1. In addition, in FIG. 6, 33 is a limit switch for detecting the displacement of the tool stand 6 in the lateral feed direction.

As shown in FIGS. 4 to 7, a swivel base 17 is supported on the main body of the tool base 6 via a bearing 35. As shown in FIGS. This turning table 17 is capable of turning around a turning shaft 16' and integrally with this turning shaft 16, and the cutting tool 5 is placed on the upper surface of this turning table 17.

This cutting tool 5 has two through holes 5a and 5b.
are provided, and bolts 18 are inserted into the through holes 5a and 5b.
is inserted in a loosely fitted state, and this bolt 18 is screwed and fixed to the upper surface of the swivel base 17, so that the cutting tool 5
is fixed on the swivel table 17 so as to be able to move slightly toward and away from the workpiece 1. Further, on this swivel table 17, a tool 0 removal equipment M22 is provided, which includes an adjustment bolt 19 fixed to the cutting tool 5, a 2m nut 20 screwed onto the adjustment bolt 19, and a support member 21 that supports the adjustment bolt 19. is provided, and by appropriately rotating the adjustment bolt 19, the relative position of the cutting tool 5 with respect to the swivel base 17 can be adjusted.

As shown in FIG. 7, the cutting tool 5 has an arc-shaped cutting edge with a radius of curvature r, and as described later, the cutting tool 5 rotates around a point that coincides with the center of curvature of the cutting edge. As such, its mounting position is adjusted by the tool zeroing device 1122.

Below the swivel table 17, as shown in FIG.
Two gears 23 and 24 are arranged in parallel in the vertical direction. The gear 23 is fixed to the circumferential surface of the rotating shaft 16 via a key 25, and the gear 24 is directly fixed to the lower surface of the rotating shaft 16 while being fitted onto the outer circumferential surface of the gear 23. .

On the other hand, a ball screw 26 is rotatably supported on the main body of the tool stand 6, and two ball screw nuts 27 that mesh with the ball screw 26 are provided in series, and the gear 23. A rack 28, 29 is fixed which meshes with each of 24. The ball screw 26 is connected to a swing drive motor (tool rotation drive means) 30 fixed to the side of the tool stand 6 via a shaft coupling device 31.

As the ball screw 26 is rotationally driven by the swing drive motor 30, the ball screw nut 27 that meshes with the ball screw nut 27 and the two racks 28 and 29 are moved in translation, and the movement of the rack 28 and 29 causes these to move in translation. The meshing gears 23 and 24, the pivot shaft 16, and the pivot base 17 are integrally driven to pivot, thereby cutting the cutting tool 5.
is adapted to pivot relative to the workpiece 1.

In the figure, reference numeral 35 denotes a limit switch for detecting both limit positions of the rotation of the swivel base 17.

Furthermore, as shown in FIG. 1, the lathe in this embodiment includes an operation 113 for inputting a predetermined machining command.
6, and a control I board 37 equipped with a computer. This control W37 includes a rotation detector 38 for the workpiece 1 provided on the headstock 2, each limit switch including the limit switches 33 and 34,
The lti control panel 37 receives these signals and outputs control signals to each motor.

Next, the method for machining workpiece 1 using this lathe will be explained in the eighth section.
This will be explained based on the flowchart shown in the figure.

First, before machining, cutting conditions are set (step S1). The cutting conditions here include the material of the cutting tool 5, the radius of curvature r1 of its cutting edge, the degree of cutting (relative speed between the workpiece 1 and the cutting tool 5) υ, and the feed rate (vertical feed fl per one rotation of the workpiece) f. , the turning angular velocity β of the cutting tool 5, and the like.

The radius of curvature r and the feed rate f of the cutting edge can be determined from the required surface roughness Rwax of the workpiece 1. That is, these values include Rmax-f2
It is known that there is a relationship such as / (8·r>...■), so the radius of curvature r and the feed rate 1.f f can be set from this required surface roughness Rwax. In this case, by setting the radius of curvature r of the cutting edge large, the feed rate [f can also be increased, thereby increasing the machining speed. The radius of curvature of the cutting edge must also be set large, which leads to an increase in the size of the device. Therefore, it is desirable to set the radius of curvature of the cutting edge in consideration of the balance between the two.

In addition, as for the cutting speed, the higher the cutting speed υ, the faster the machining can be achieved, but the tool life will be shortened, so it is necessary to set the cutting speed in consideration of both factors. .

Furthermore, the turning angular velocity of the cutting tool 5 (i.e., the turning base 17
The turning angular velocity) β is set so that the entire area of the cutting edge contacts the workpiece 1 from the start to the end of machining. In other words, the central angle of the cutting edge arc is θ,
When the cutting time required for machining is t, the angular velocity β is set to β-θ/l...■. Note that this cutting time t is determined from the total length L1 of the workpiece area of the workpiece 1, the cutting degree υ, and the feed rate f.

In the case of an NC lathe, the above setting values may be input into the program, or in other cases, the obtained values may be manually set using a speed adjustment dial, dial, etc.

After setting the cutting conditions in this way, the workpiece 1 is set between the headstock 2 and the spindle 3 (step S2), and the cutting tool 5 is mounted on the turning table 17 (step S3). .

To install the cutting tool 5, first place the cutting tool 5 in a predetermined position on the swivel table 17, and then insert the cutting tool 5 into the through hole 5a.

After inserting the bolt 18 into 5b and fixing it to the swivel base 17,
An adjustment bolt 19 of a tool 6 ejecting device 22 is fixed to the tail end of the cutting tool 5, and by rotating this bolt 19 and sliding the cutting tool 5, the center of rotation thereof is adjusted. Here, the position of the cutting tool 5 is adjusted so that the center of curvature of the cutting edge shape of the cutting tool 5 coincides with its center of rotation (point C in FIG. 7). Regarding this position adjustment, a measuring device such as a dial indicator is brought into contact with the tool cutting edge, and the cutting edge is adjusted to a position where the cutting edge will not be displaced in the radial direction even if the tool 5 is turned in any direction.
The above conditions can be satisfied. In addition, when the standby position of the carriage 4 before processing is set near the Shinshindai 3, the dial indicator 38 is fixed to the side of the Shinshindai 3 as shown in FIG. By this,
This dial indicator 38 can be used to center the cutting tool 5 at the standby position, which is very rational.

Next, by operating the vertical feed drive motor 10, the cutting tool 5 is moved to the starting point of machining (the right end of the workpiece in FIG. 1).
(step S4), move the swivel table 17 to the origin position (in FIG. 1, the most rotated position in the clockwise direction), and in this state, rotate the main motor to rotate the workpiece 1 at a predetermined rotation speed ( It is rotated at a rotational speed corresponding to the cutting speed υ (step 85). Then, as shown by the two-dot chain line on the right side of FIG. ).

After the origin position is set in this way, the cutting tool 5 is moved slightly away from the workpiece 1.

Then, by receiving a switch operation on the operation panel 36, the cutting tool 5 is brought into contact with the workpiece 1 again while discharging cooling means such as cutting oil and air, and machining of the workpiece 1 is started (step 87 ).

This processing is performed by vertically feeding the carriage 4 at the above-mentioned feed rate and simultaneously rotating the swivel table 17 at the above-mentioned angular velocity β (step Ss). As a result, the workpiece 1 is machined with the new part of the tool cutting edge constantly in contact with the workpiece, and moreover, while the carriage 4 moves from the processing start point to the finishing point, the entire area of the tool cutting edge touches the workpiece. It will come into contact with piece 1. Further, since the cutting tool 5 is rotated around the same point as the center of curvature of the tool cutting edge, the depth of cut does not change.

After finishing the cutting process in this way (YES in step S9), the cutting tool is returned to the standby position before machining by driving the vertical feed drive motor 10 and the horizontal feed drive motor 15 (step 5111), and the main After stopping the motor (step 511), the workpiece 1 is removed from the lathe (step 512), thereby completing the entire machining process.

As described above, in machining using this lathe, turning is performed while rotating the cutting tool 5, so that the following effects can be obtained compared to conventional lathes.

(2) During machining, a new cutting edge is constantly supplied by the rotation of the cutting tool 5, so the cutting time for the same part of the cutting edge is short, and the degree of wear is extremely low. Therefore, the life of the tool can be significantly extended, and cutting accuracy can be improved.

■By extending the tool life in this way, the cutting speed υ can be set much higher than before, so the machining time can be significantly shortened, thereby increasing the speed of machining. Furthermore, since there is no need to change tools during all machining steps, machining efficiency is further improved, and no joint steps occur due to tool changes.

As described above, this lathe allows for faster and more accurate machining by extending the tool life, so it can be used consistently from rough machining to finishing machining without using conventional grinding machining. This can be done by turning,
This can significantly reduce equipment costs. Moreover, in the case of turning, compared to grinding, the desired surface roughness can be obtained by adjusting the feed rate f without changing the tool, and the tool is small and lightweight, easy to handle, and can be replaced automatically. It is also possible to recycle the tool after its life has ended, and the advantages include: - It is possible to take a large cutting interval, and - It is not necessary to use a large amount of grinding fluid or to clean and treat the grindstone powder after machining. Therefore, being able to omit the grinding process is of great significance.

Furthermore, as mentioned above, if the entire area of the tool cutting edge is brought into contact with the workpiece 1 until the machining is finished,
Since the tool cutting edge will wear evenly, the cutting tool 5
It is possible to reuse the tool, and it is also extremely easy to grind the tool during playback.

Note that the present invention is not limited to the above-mentioned embodiments, and similar effects can be obtained by implementing the following embodiments.

(2) In the above embodiment, the cutting edge of the tool is arcuate, but the center angle may be large or small, and the cutting edge may be provided in a circular shape over the entire circumference of the tool, for example. Moreover, it does not have to be a precise circular arc as long as the cutting accuracy is within an allowable range.

■In the above embodiment, cutting is performed using a single cutting tool 5, but in the case of rough machining in particular, conventional small cutting tools may be arranged in parallel in the circumferential direction. . Further, a plurality of tools 5 similar to those in the above embodiment are arranged in a turret type on the tool stand 6 or arranged in parallel in the circumferential direction,
If the tool can be changed by rotation, the tool changing operation can be performed more smoothly. Furthermore, like conventional machine tools, it is also possible to include an ATC (automatic personnel changer).

■In the above embodiment, the center of curvature of the tool cutting edge and the turning base 17
However, if the center of curvature of the tool cutting edge is slightly shifted from the center of rotation of the swivel table 17, the depth of cut will gradually change from both ends of the workpiece 1 to the center of the workpiece 1. This makes it possible to extremely easily perform circular arc processing such as crown processing in which the center portion is slightly bulged.

(2) In the above embodiment, the translational drive and rotational drive in each axis are automatically controlled, but these may also be controlled manually by operating a handle or the like.

〔Effect of the invention〕

As described above, the present invention has a cutting edge of a tool having an arc shape, a tool stand configured such that the tool can be rotated around a point that substantially coincides with the center of curvature of the cutting edge shape, and a tool base that allows the tool to be rotated. This tool is equipped with a tool rotation drive means that rotates the tool relative to the rotating workpiece while moving it in the direction of the rotational axis of the workpiece, resulting in less wear on the cutting edge and longer tool life than before. It is possible to perform long machining. Accordingly, it is possible to increase the precision of machining, increase the speed of machining by increasing cutting speed, and further improve machining efficiency by omitting tool exchange.

Furthermore, in addition to the high precision of machining mentioned above, finishing machining can also be performed by turning in the same way as rough machining, eliminating the need for grinding machining, and thereby significantly reducing equipment costs. You can also save money.

In addition, if the tool is rotated so that the entire area of the tool tip contacts the workpiece while the tool rest moves over the entire area of the workpiece, the tool edge will be used evenly. As a result, the tool can be reused, and tool grinding work during remanufacturing is also facilitated.

[Brief explanation of the drawing]

jRI is a schematic plan view of a lathe according to an embodiment of the present invention, FIG. 2 is a vertical cross-sectional front view of the same lathe, FIG. 3 is a cross-sectional side view of the same lathe, and FIG. 5 is a sectional view taken along the line v-v in FIG. 6, FIG. 6 is a front view of the carriage in the lathe, FIG. 7 is a plan view of the carriage, and FIG. 8 is the lathe. FIG. 9 is a plan view of the vicinity of the tailstock of the same lathe. 1... Workpiece (workpiece), 2... Headstock (
Workpiece support rotation means), V tool “;”, o
...Longitudinal feed drive motor (feeding means), 15...Horizontal feed drive motor (feeding means), 3o...Swivel drive motor (tool rotation drive means), 37...-1iIlts
Board. Patent applicant Agent: Shin Nippon Koki Co., Ltd.
Patent Attorney Etsushi Kotani Patent Attorney Chief 1) Patent Attorney Yasuo Itayaqfu

Claims (1)

[Scope of Claims] 1. A tool stand that supports a tool, a workpiece support and rotation means that supports and rotates a workpiece, a direction of approaching and separating from the workpiece, and a rotation of the workpiece. In a lathe equipped with a feeding means for relatively moving the tool stand in the axial direction, the cutting edge of the tool is formed into an arc shape, and the tool is rotatable around a point that substantially coincides with the center of curvature of the cutting edge shape. A lathe comprising the tool stand and a tool rotation drive means for rotating the tool. 2. A tool having an arc-shaped cutting edge is supported so as to be rotatable about a point that substantially coincides with the center of curvature of the cutting edge shape, and a tool rotation driving means for rotating the tool is provided. A tool stand for a lathe according to claim 1. 3. Rotate the workpiece, and while the tool is in contact with the workpiece, rotate the tool having an arc-shaped cutting edge around a point that approximately coincides with the center of curvature of the cutting edge shape. 2. The method of machining using a lathe according to claim 1, wherein the lathe is moved relatively in the direction of its rotation axis.