JPH04343614A - Electric tapping tool - Google Patents

Abstract

PURPOSE:To sharply improve the efficiency of the tapping work by providing the rotating speed detecting means of a rotary shaft and a switching means switching the rotation direction of a motor when the preset rotating speed is attained to repeat the forward/reverse rotations of the rotary shaft. CONSTITUTION:When a power switch 7 is closed, a motor 2 is rotated, and a rotary shaft is rotated forward. The first count number N1 is preset in a programmable down-counter 12, when the rotating speed of the rotary shaft reaches the preset rotating speed proportional to the first count number N1, transfer switches 10a-10c are switched, the rotation direction of the motor 2 is switched, and the rotary shaft is switched to the reverse rotation. When the rotating speed reaches the preset rotating speed proportional to the second count number N2, the transfer switches 10a-10c are again switched, the rotation direction of the motor 2 is switched, and the rotary shaft is switched to the forward rotation. Whenever the rotating speed of the rotary shaft reaches the preset rotating speed thereafter, the rotary shaft is repeatedly switched to the forward/reverse rotations.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electric tap cutting tool for cutting a female thread using a tap, which is a male thread type tool.

[Conventional technology]

Conventionally, tap cutting work has been performed using an electric rotary tool that can be switched between forward and reverse rotation.

That is, by attaching a machining tap to the rotating shaft of a rotary tool,
First, the rotary tool is rotated in the normal direction to cut the thread, and when the thread has been cut to a certain extent, the rotary tool is rotated in the reverse direction, the tap is returned a little, and then the rotary tool is rotated in the forward direction to cut the thread again. Repeat this series of actions to turn off the tap.

[Problem to be solved by the invention]

In tap cutting work using a rotary tool as described above, the operator manually switches the rotary tool between forward and reverse directions one by one, and this has to be done frequently, which is extremely time-consuming and troublesome. It was a lot of work, and the work efficiency was poor. Moreover, the timing of switching the rotation direction of a rotary tool depends on the user's intuition, and if the rotation is reversed for an unnecessarily long time, machining time will be increased, further reducing work efficiency. There was also the problem.

The present invention has been made in view of the above circumstances, and its object is to provide a tap cutting tool that can perform tap cutting work with extremely high efficiency.

[Means to solve the problem]

In order to solve this problem, the electric tap cutting tool of the present invention includes a rotation number detection means for detecting the number of rotations of a rotating shaft on which a tap is attached, and a means for detecting the number of rotations of the rotating shaft when the number of rotations of the rotating shaft reaches a predetermined number of rotations. , switch the rotation direction of the motor,
The rotating shaft is provided with a switching means for repeatedly rotating the rotating shaft in forward and reverse directions.

[Effect]

The electric tap cutting tool of the present invention is provided with a switching means that switches the rotation direction of the motor when the number of rotations of the rotary shaft reaches a predetermined number of times, so that the rotary shaft automatically rotates at a predetermined number of times. Repeat forward and reverse rotation.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on FIGS. 1 and 2.

FIG. 2 shows the overall structure of the tap cutting tool, the outer shell of which is formed by a generally T-shaped housing 1. The housing 1 houses a motor 2, which is a brushless motor, a speed reducer 3, and a rotating shaft 4, and these motor 2, speed reducer 3, and rotating shaft 4 are connected to form a rotation transmission system. . The rotary shaft 4 has its tip projected from the housing 1, and is fitted with a machining tap (not shown) of a well-known structure. Reference numeral 6 denotes a battery pack that is detachably attached to the lower surface of the handle portion of the housing 1.

The battery pack 6 contains a rechargeable battery and is connected to the motor 2 via a power switch 7. 8 is a circuit board on which circuit blocks such as a switching means 13, which will be described later, are loaded.

FIG. 1 shows the configuration of a circuit block, in which 2a is the rotor of the motor 2, and 2b is the stator coil. The rotor 2a has a four-pole permanent magnet portion 2c on its outer periphery, and the stator coil 2b is a three-phase coil. Ha, Hb, and Hc are Hall elements disposed around the rotor 2a, and form rotation number detection means 9 for detecting the number of times the motor 2 has rotated. The Hall element H
Since the permanent magnet portion 2c of the rotor 2a has four poles, a, Hb, and Hc output two cycles of approximately AC wave-shaped pulses each time the rotor 2a rotates once. Therefore, the number of rotations of the motor 2 can be detected from the number of pulses output from the Hall elements Ha, Hb, and Hc. Each Hall element Ha, Hb, Hc is a selector switch 10a,
Motor control IC11 via 10b and 10c
It is connected to the. The motor control IC 11 is
According to the outputs from the Hall elements Ha, Hb, and Hc, drive signals are output to driver circuits D1 to D6 of six switching elements Q1 to Q6 to control the rotation of the motor 2.

Three Hall elements Ha forming the rotation number detection means 9,
One of Hb and Hc is connected to the programmer pull-down counter 12. A switching means 13 is formed by the programmer pull-down counter 12 and the changeover switches 10a, 10b, and 10c. The switching means 1
3, when the number of rotations of the motor 2, that is, the number of rotations of the rotating shaft 4 reaches a predetermined number of rotations, the direction of rotation of the motor 2 is switched to cause the motor 2 to repeat forward and reverse rotations.

In the programmer pull-down counter 12, by switching the number setting switch 14, either one of the first count number N1 and the second count number N2 proportional to a predetermined number of rotations is preset, and the number of rotations detection means Every time a pulse is output from the Hall element Hc 9, this pulse is counted and subtracted from the preset count number. Then, when the count number reaches zero, the programmer pull-down counter 1
2 outputs a signal to the changeover switches 10a, 10b, 10c and the number of times setting switch 14, which switches the changeover switches 10a, 10b, 10c, and changes each Hall element Ha, H input to the motor control IC 11.
b, reverse the polarity of the output of Hc and switch the rotation direction of the motor 2. At the same time, the number setting switch 14 is switched and the programmer pull-down counter 12 is set to
The other count number that is not the previously preset count number is preset.

The subsequent steps are the same as before, and when the count number reaches zero, the programmer pull-down counter 12 switches the changeover switches 10a, 10b, and 10c again to reverse the motor 2. The above operation is repeated until the power switch 7 is opened, and the motor 2 repeats forward and reverse rotation.

The first and second count numbers N1 and N2, which are switched by the number setting switch 14, are such that the first count number N1 is the number of rotations of the rotating shaft 4 when the motor rotates in the normal direction, and the second count number N2 is the number of rotations when the motor rotates in the reverse direction. The number is set in proportion to the number of rotations of
It is assumed that N1>N2.

When using the tap cutting tool configured as described above, when a machining tap is attached to the chuck 5 and the power switch 7 is closed, the motor 2 rotates and the rotating shaft 4 first rotates in the normal direction. At this time, a first count number N1 is preset in the programmer pull-down counter 12, and when the number of rotations of the rotating shaft 4 reaches a predetermined number of times proportional to the first count number N1, the changeover switches 10a, 10b, 10c is switched, the rotation direction of the motor 2 is switched, and the rotating shaft 4 is switched to reverse rotation. Next, when the number of rotations of the rotating shaft 4 reaches a predetermined count number proportional to the second count number N2, the changeover switches 10a, 10b, 10c are set again.
is switched, the rotation direction of motor 2 is switched,
The rotating shaft 4 switches to normal rotation. Thereafter, each time the number of rotations of the rotary shaft 4 reaches a predetermined number, the rotation direction of the motor 2 is switched, and the rotary shaft 4 repeats forward and reverse rotation.

In the above embodiment, a brushless motor is used as the motor 2, but this is because the brushless motor has a built-in Hall element for detecting the position of the rotor for rotation control. This is because the output of this Hall element can be used to detect the number of rotations of 4. Further, it is naturally possible to employ a general commutator motor other than a brushless motor, and in this case, the rotation number detection means may be configured by means for detecting the rotation of a motor such as a frequency generator.

〔Effect of the invention〕

Since the electric tap cutting tool of the present invention is configured as described above, it includes a rotation number detection means for detecting the number of times the rotating shaft has rotated, and a rotation number detecting means for detecting the number of rotations of the rotating shaft, and a motor that rotates when the number of rotations of the rotating shaft reaches a predetermined number of rotations. By providing a switching means that switches the direction and repeatedly rotates the rotating shaft in forward and reverse directions, the rotating shaft can automatically switch between forward and reverse rotation at a predetermined number of rotations, allowing the user to manually rotate the rotating shaft in forward and reverse directions. Since there is no need to change the rotation, the efficiency of tap cutting work is greatly improved. Furthermore, since the rotating shaft does not rotate more than necessary, there is no need for additional machining time.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram of an embodiment of the present invention, and FIG. 2 is a sectional view showing its structure. 2...Motor, 4...Rotating shaft, 9...Rotation number detection means, 13...Switching means. Patent applicant Matsushita Electric Works Co., Ltd.

Claims (1)

[Claims] 1. An electric tap cutting tool comprising a motor capable of forward and reverse rotation, a rotating shaft rotationally driven by the motor, and a tap attached to the rotating shaft, An electric motor comprising a rotation number detection means for detecting the number of rotations, and a switching means for switching the rotation direction of the motor and causing the rotation shaft to repeat forward and reverse rotations when the rotation number of the rotation shaft reaches a predetermined number of rotations. Tap cutting tool.