JPS6125493B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a screw tapping device using a tap with a drill.

Tapping a screw using a tap with a drill has the advantage of high work efficiency because it can cut the pilot hole and the female thread in one process. However, in this case, the feed amount of the drill is limited to 0.1 mm to 0.3 mm per rotation of the spindle, whereas the feed amount of the tap is usually 1.0 mm to 3.0 mm to correspond to the pitch of the screw. The feed must be 10 times more than that for drilling.

Conventionally, screw tapping devices using a tap with a drill and equipped with a hydraulic feeding mechanism are known. In this conventional device, the feed rate by the hydraulic cylinder is controlled by a flow rate adjustment valve, so that it is slowed down when feeding a drill, and when feeding a tap, it is designed to give a feed amount equivalent to the pitch of the screw per revolution of the tap. It uses a hydraulically driven feeding mechanism. However, it is difficult to adjust the feed rate of the tap, and even if it is adjusted, as the temperature of the oil fed into the cylinder rises, the feed rate of the tap tends to increase, resulting in cutting problems. The fatal flaw was that the precision of the internal thread was poor.

The present invention has been made with the aim of solving the above-mentioned drawbacks, and uses a feed screw shaft for tap feed to enable accurate pitch feed, and uses hydraulic pressure for drill feed and forward/backward movement of the entire tool. To provide a screw tapping device that is simple in structure and can efficiently cut female threads with high precision by using a mechanism in combination.

Hereinafter, one embodiment of the present invention will be described based on the drawings. 1 is a base, 2 is a movable casing that is slidably attached to the base 1, and a rotary drive device 3 such as a geared motor is mounted on the top of the movable casing, and together with the rotary drive device 3, a main shaft, which will be described later, is mounted. It is designed to be able to reciprocate in the axial direction, that is, in the tap feeding direction.

Reference numeral 4 denotes a main shaft, which is rotatably supported by the casing 2 via bearings 5 and 6, and has a chuck 8 on its tip protrusion for attaching a drilled tap 7, and a driven pulley 9 wedged on its rear protrusion. A belt 12 is stretched between the passive pulley 9 and a transmission pulley 11 wedged on the output shaft 10 of the rotary drive device 3, so that the main shaft 4 is driven to rotate at a constant speed.

13 is a feed screw shaft arranged parallel to the main shaft 4, the front half of which is formed as a spline shaft 13a, the rear half of which is formed as a screw shaft 13b, and the spline shaft portion 13a is fixed to the side wall of the casing 2. The threaded shaft portion 13b is fitted into the splined cylinder 14 and supported so as to be non-rotatable but slidable only in the axial direction.
is screwed onto and supported by the female threaded body 15. The female threaded body 15 is rotatably supported by a bracket 16 fixed to the side wall of the casing 2 via a bush 17. Further, a gear 18 is integrally provided on the female threaded body 15, and a gear 19 that meshes with the gear 18 is loosely fitted to the main shaft 4. 20 is an electromagnetic clutch for interlocking the gear 19 with the main shaft 4; when the clutch operates, the gear 19 moves in conjunction with the main shaft 4;
The rotational force is transmitted to the female threaded body 15 through the gear 18, and the rotation of the female threaded body 15 causes a gap between the feed screw shaft 13 fixed to a hydraulic cylinder device 21, which will be described later, and the female threaded body 15. A relative movement in the axial direction occurs at . Therefore, the casing 2 and the drilled tap 7 move in the axial direction. The amount of movement in this axial direction is the gears 18 and 19.
By adjusting the ratio of the number of teeth, it is set to correspond to the thread pitch of the drilled tap 7 used for one revolution of the main shaft 4.

Reference numeral 21 denotes a hydraulic cylinder device, which is fixed to the base 1 by a coaxially disposed bracket 36 behind the feed screw shaft 13, and its piston rod 22 is connected to the rear end of the feed screw shaft 13. The hydraulic cylinder device 21 is used for feeding the drill tap 7 and moving the movable casing 2 forward and backward.

Next, the operation will be explained. When the hydraulic cylinder device 21 operates and the casing 2 moves forward in rapid motion, and the tip of the tap 7 with the drill approaches the workpiece 35,
The kicker 23 pushes the flow rate regulating valve 24 to switch to drill feed. At this time, the electromagnetic clutch 20 is demagnetized and disconnected. Therefore, the female threaded body 15 does not rotate.

When the drill part 7a of the tap 7 with a drill completes the drilling of the pre-screw hole, the kicker 25 pushes the limit switch 26 to switch the port of the switching solenoid valve 27 (see FIG. 2) of the hydraulic cylinder device 21 to the center.
Stop the piston and hold it fixed with pressure oil. Subsequently, the electromagnetic clutch 20 is energized, and the main shaft 4
The rotational force is transmitted to the female threaded body 15 via the gears 19 and 18. When the female threaded body 15 rotates, the feed screw shaft 13 is connected and fixed to the piston rod 22 of the hydraulic cylinder device 21, so that the female threaded body 1 rotates.
5 begins to move in the axial direction on the feed screw shaft 13, and as a result, the drilled tap 7 together with the casing 2 moves forward by an amount corresponding to the thread pitch per one revolution of the main shaft 4, as described above. Then, a female thread is cut into the workpiece by the tap portion 7b. When the tap portion 7b advances to a predetermined position and the screw tapping is completed, the kicker 28 pushes the limit switch 29 and the main shaft 4 rotates in the reverse direction, and in conjunction with this, the female screw body 1
Since 5 also rotates in the opposite direction, the casing 2 and the tap 7 with a drill are moved back by screw feeding. When the tap portion 7b is completely removed from the tapped female screw, the electromagnetic clutch 20 is disconnected and the transmission of rotational force from the main shaft 4 to the female screw body 15 is interrupted. At the same time, the kicker 30 pushes the limit switch 31 to switch the port of the switching solenoid valve 27 of the hydraulic cylinder device 21 to the left side, and the hydraulic cylinder device 21 causes the casing 2 and the tap 7 with the drill to move back to the fixed position in a fast forward motion. In the fixed position, the kick 32 pushes the limit switch 33, and the switching solenoid valve 27
The entire operation is completed by switching the port to the neutral position.

As explained above, according to the present invention, a highly accurate female thread can be cut very efficiently using a tap with a drill. Moreover, the structure is simple and the entire device can be made compact.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a vertical sectional front view of the main part, and FIG. 2 is an explanatory diagram of the cylinder device. DESCRIPTION OF SYMBOLS 1... Base, 2... Movable casing, 3... Rotation drive device, 4... Main shaft, 7... Tap with drill, 13... Feed screw shaft, 15... Female threaded body, 2
0...Electromagnetic clutch, 21...Hydraulic cylinder device.

Claims (1)

[Claims] 1. A movable casing 2 slidably attached to a base 1 in the tap feed direction, and a rotation drive device 3 attached to the casing 2.
and a main shaft 4 which is rotatably supported by the casing 2, is operatively connected to the rotary drive device 3, and is provided with a chuck 8 on its tip to which a tap 7 with a drill is attached, and parallel to the main shaft 4. a feed screw shaft 13 which is disposed in the casing 2, is supported by the casing 2 so as to be non-rotatable but slidable only in the axial direction, and is threaded into a female threaded body 15 rotatably attached to the casing 2; Transmission devices 18 and 19 that rotate the female threaded body 15 in conjunction with the main shaft 4; and transmission devices 18 and 19 that are interposed between the transmission devices 18 and 19 and the main shaft 4 to transmit rotational force from the main shaft 4 to the female threaded body 15. or a shutoff clutch 20, which is fixed to the base 1 and whose piston rod 2
2, a cylinder device 21 connected to the feed screw shaft 13;