JPH032601B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a machine tool capable of performing taper thread cutting and the like.

Conventionally, machine tools that perform taper thread cutting, etc. are capable of opening and closing the tool in the radial direction along the tapered surface of a motion direction changing member that advances and retreats while rotating, and is controlled by a separately provided taper block for setting the taper. A rotating gear mechanism causes the tool to expand at a predetermined speed. However, this technique has the disadvantage that the accuracy of taper setting by the taper block is not sufficient, and the sliding between the tapered surfaces as the tool opens and closes is not smooth. Another disadvantage is that the mechanism for transmitting the tool opening/closing operation by the taper block to the tool becomes complicated.

In view of the above circumstances, the present invention displaces a tool in the radial direction with high precision under NC control by mutual movement between inclined surfaces via a slide bearing, and combines this displacement with rotation and axial movement. The object of the present invention is to provide a machine tool that performs accurate helical motion on a rotating tapered surface and performs taper thread cutting.

An embodiment in which the present invention is applied to a thread cutting machine will be described below based on the drawings. Fig. 1 is a longitudinal cross-sectional view of the thread cutting machine, the whole of which is indicated by the number 1, Fig. 2 is a partially cutaway front view as seen from arrow A in Fig. 1, and Fig. 3 is a plane seen from arrow B in Fig. 2. It is a diagram. 2 is a spindle housing of the thread cutting machine 1. The spindle housing 2 is placed on a housing retract base 3 so as to be movable in the Z-axis direction (parallel to the spindle axis). A Z-axis DC servo motor 5 (first
A gear 6 is attached to the output shaft of the drive means (driving means), and a gear 7 that meshes with the gear 6 is fixed to the rear end of a screw rod 8 in the Z-axis direction. Also housing retract base 3
A bushing 10 is fitted and fixed in a mounting hole 9 drilled in the bushing 10, and a bearing 11 mounted in the bushing 10 rotatably supports the vicinity of the rear end of the threaded rod 8. Furthermore, the front end of the screw rod 8 is pivotally supported by a bearing bracket 12 mounted on the housing retract base 3. A nut 13 with a flange 13a is screwed into the threaded rod 8, and the nut 13 is fitted into a mounting hole 14 formed in the spindle housing 2, and the flange 13a is fixed to the spindle housing 2 by a screw 15. . Therefore, when the Z-axis DC servo motor 5 is driven, the spindle housing 2 is moved back and forth in the Z-axis direction due to the rotation of the screw rod 8.
By retracting the housing retract base 3 in the Z-axis direction with the spindle housing 2 placed thereon, it is possible to quickly create a space in front of the spindle housing 2 for tool replacement work.

Next, the spindle will be explained. A flange 16 is fixed to the front part of the spindle housing 2,
A bearing 17 is provided within the flange 16 . Further, a bush 18 is fixed within the spindle housing 2, and a bearing 19 is provided within the bush 18. A spindle 20 is rotatably supported by both bearings 17 and 19, and is driven by a known drive device (not shown).

Next, holding the tool will be explained. A die head 24 is attached to the front of the spindle 20. Bearing units 26, 27 are fixed to the die head 24 within mounting holes 25, 25, . . . arranged on the circumference of the die head 24. The bearing units 26, 27 and the roller bearings 28, 29, 30, 31, 32, 33 provided in the die head 24 allow the tool holding member 34 to be positioned within the mounting hole 25 in the longitudinal direction (Z-axis) and rotational direction. It is possible to move freely in the radial direction while being restricted. A groove 34a is formed at the front end of the tool holding member 34 facing outward from a cover plate 35 attached to the die head 24, and a chaser 36 (thread cutting tool) is inserted into the groove 34a.
is removably attached. Also, the tool holding member 3
4 has a through hole 34b formed in the radial direction. A plug 37 is screwed into the outer end of the through hole 34b, and a protrusion 38 is retractably fitted into the inner end of the through hole 34b. The abutment 38 is connected to the die head 2
The cover tube 39 comes into contact with the outer circumferential surface of the cover tube 39 fixed to the cover tube 4 .
A spring 40 is interposed in the through hole 34b as a biasing means so as to be compressed between the plug 37 and the abutment 38. The tool holding member 34 is therefore biased radially outwardly by the spring 40. The tool holding member 34 has a rearward protrusion 34c, and the protrusion 34c has an inclined surface 34d. Nao 4
1 is a gib interposed between the bearing unit 26 and the die head 24.

Next, opening and closing of the tool holding member 34 will be explained. X-axis DC servo motor 42 (second drive means) attached to the rear end of the spindle housing 2
A gear 43 is attached to the output shaft of the gear 43, and a gear 44 that meshes with the gear 43 is fixed to the rear end of a screw rod 45 in the Z-axis direction. Further, a bush 47 is fitted and fixed in a mounting hole 46 formed in the spindle housing 2, and a bearing 48 mounted in the bush 47 rotatably supports the vicinity of the rear end of the screw rod 45. Furthermore, the front end of the screw rod 45 is connected to the spindle housing 2.
The shaft is supported by a bearing 49 mounted on the shaft. screw rod 45
A nut 50 with a flange 50a is screwed into the bracket 50, and the nut 50 is fitted into a mounting hole 51a formed in a bracket 51, and the flange 50a is fixed to the bracket 51 with a screw 52. A mounting hole 51b is further formed in the bracket 51 in the Z-axis direction, and a guide bar 53 passes through the mounting hole 51b.
Both ends of the guide bar 53 are fixedly held by the spindle housing 2. and guide bar 5
3 guides the bracket 51 to move back and forth in the Z-axis direction by means of bearings 54, 54 provided so as to be interposed between the guide bar 53 and the bracket 51. Further, a protrusion 55 for front and rear positioning is attached to a predetermined position of the bracket 51.
On the other hand, an opening 56 is formed in the spindle housing 2 so that the protrusion 55 can move back and forth as the bracket 51 moves back and forth. A restricting member 5 is provided on the inner wall of the opening 56 to abut against the protrusion 55 when the protrusion 55 moves back and forth, and to restrict the extreme position of the protrusion 55.
7,57 is attached. Note that 58 is the opening 5.
6 is a cover provided on the spindle housing 2 above the spindle housing 2. Furthermore, a mounting hole 51 is provided in the bracket 51.
c is drilled in the Z-axis direction. A connecting rod 59 is fitted into the mounting hole 51c and locked with a key 60, and a nut 61 screwed into the connecting rod 59 prevents the bracket 51 and the connecting rod 59 from shifting in the axial direction. The connecting rod 59 is connected to the hole 2 of the spindle 20.
0a and extends into the die head 24 with a bearing 62 interposed between the connecting rod 59 and the spindle 20. An opening/closing member 63 is rotatably attached to the front part of the connecting rod 59 via a bearing 64. 65 is a bearing holder. The opening/closing member 63
is movably supported in the enlarged hole 66 of the spindle 20. The opening/closing member 63 is guided in the axial direction via a bearing 68 provided on its arm 67 along a guide bar 68a provided on the die head 24, and relative rotation of the opening/closing member 63 with respect to the die head 24 is restricted. . The opening/closing member 63 also has an arm 69, and the inner surface of the arm 69 is provided with an inclined surface 70 parallel to the inclined surface 34d of the protrusion 34c. An axial surface 24 provided on the inner circumference of the die head 24
A bearing 71 is interposed between the arm 69 and an axial surface 69a provided on the outer periphery of the arm 69. Also, the tool holding member 34
A bearing 72 is interposed between the inclined surface 34d of the arm 69 and the inclined surface 70 of the arm 69.

73 is a backup cylinder attached to the rear of the spindle housing 2. An abutting adapter 75, which is an abutting member that applies a predetermined back pressure to regulate the forward and backward movement of the connecting rod, is screwed onto the piston rod 74 of the back-up cylinder 73, and the abutting adapter 75 is attached to the back of the bracket 51. comes into contact with. Since an unload valve (not shown) is provided in the hydraulic circuit of the backup cylinder 73, the abutment adapter 75 applies a predetermined back pressure to the bracket 51 when the bracket 51 moves backward.

Next, 76 is an inner support that grips the inner surface of the end of a steel pipe 77 such as an oil country pipe. The guide tube 78 of the inner support 76 is connected to the connecting rod 5.
A guide 79 is provided at the rear end of the guide tube 78 and is slidable in the axial direction along the guide bar 80 .

The thread cutting machine 1 of the present invention has the above configuration, and its effects will be explained below. First, with the spindle housing 2 retracted, the steel pipe 77
will be brought in. The guide tube 78 is moved forward, the inner support 76 grips the end of the steel pipe 77, a detection device (not shown) detects the end of the pipe to be threaded, and a clamp device (not shown) grips the steel pipe 77 at an appropriate position. Next, while rotating the spindle 20, move the spindle housing 2 to Z.
advance in the axial direction. When the cheeser 36 reaches the predetermined position of the detected tip, processing begins. When the opening/closing member 63 is moved relatively backward in the Z-axis direction with respect to the die head 24 by driving the X-axis DC servo motor 42, the tool holding member 34 performs an opening operation due to the biasing force of the spring 40. Therefore, under NC control, the X-axis DC servo motor 4 is moved so that the tool holding member 34 opens by a predetermined distance corresponding to the distance that the cheezer 36 advances in the Z-axis direction from the end of the steel pipe 77.
2, the steel pipe 77 can be machined with a taper thread along the desired rotational taper surface. By adjusting the opening speed of the tool holding member 34,
An arbitrary rotational taper surface can be obtained. Moreover, the opening/closing member 63 is connected to the die head 24 and the tool holding member 3.
4 through bearings 71 and 72, respectively, so that the axial movement of the opening/closing member 63 can be smoothly and precisely converted into the radial movement of the tool holding member 34. Furthermore, since the back-up cylinder 73 prevents the connecting rod 59 from moving back excessively, the tool holding member 34 is prevented from opening too much due to centrifugal force.

Furthermore, as shown in Fig. 1, parallel threads can be machined by operating only the Z-axis DC servo motor 5 without operating the X-axis DC servo motor 42, and furthermore, by replacing the chaser 36 with a normal cutting tool. Cylindrical machining and taper machining are also possible, allowing for diversified machining.

Since the present invention is configured as described above, the following effects can be expected. That is,
In order to move the tool holding member to which the cutter is attached in the radial direction of the die head, an opening/closing member having an inclined surface corresponding to the inclined surface formed at the rear of the tool holding member is attached in the direction of the spindle axis. This is done by moving back and forth. Furthermore, since bearings are interposed between these inclined surfaces, stable and reliable feeding can be achieved.

Further, the opening/closing member is restricted from moving back and forth by an abutment member connected to the backup cylinder at the rear. Therefore, even when the tool holding member is rotated, the opening/closing member does not return, resulting in a machine tool that can perform taper thread cutting with high precision.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view, FIG. 2 is a front view taken along arrow A in FIG. 1, and FIG. 3 is a plan view taken along arrow B in FIG. 1...Thread cutting machine, 2...Spindle housing,
5...Z-axis DC servo motor (first drive means), 3
4... Tool holding member, 34d... Inclined surface, 36... Chaser, 40... Spring, 42... X-axis DC servo motor (second drive means), 63... Opening/closing member, 70... Inclined surface, 71, 72... Bearing , 75...Abutment adapter (abutment member).

Claims (1)

[Claims] 1. A spindle housing that is movable relative to the workpiece, a spindle that is rotatably supported within the spindle housing, and an opening/closing device that rotates with the spindle, is rotatably supported in the axial direction, and has an inclined surface. a member, and an inclined surface that is provided on the spindle and faces the inclined surface of the opening/closing member across a bearing, and moves in a radial direction perpendicular to the axis of the spindle in conjunction with movement of the opening/closing member. a freely guided tool holding member; urging means for urging the tool holding member in the radially expanding side;
a first drive means for relative movement under NC control; a second drive means for moving the opening/closing member in the axial direction of the spindle under NC control while rotating the spindle; a connecting rod that presses the opening/closing member relatively rotatably in the axial direction in response to the driving force of the second driving means; and a connecting rod that is provided on the spindle housing and applies a predetermined back pressure to advance and retreat the connecting rod. A machine tool consisting of a regulating abutment member.