JPS6025662A - Variable speed gear for motorized driver - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a transmission device for an electric screwdriver that outputs a transmission output via a planetary gear mechanism.

(B) Background and Background of the Invention Conventionally, small electric screwdrivers have been used mainly for relatively light-load rotating operations with high-speed, low-torque rotation. In recent years, electric screwdrivers that are capable of low-speed, high-torque rotation have been provided, as there is a desire for a screwdriver that can produce high torque output even at low speeds.

However, in this case, because it is small, it does not have torque and cannot be applied to a wide range of rotational work, resulting in a decrease in work efficiency.

In addition, the output structure has a problem that the transmission mechanism and its transmission changeover mechanism require many gears, making the structure complicated and large, resulting in high cost.

(c) Purpose of the Invention Therefore, the object of the present invention is to provide a transmission device for an electric screwdriver that can easily obtain different transmission outputs for high speed and low speed without complicating the structure.

(D) Summary of the Invention The present invention is a transmission device for an electric screwdriver that can output both high-speed transmission output and low-speed transmission output through a small planetary gear mechanism that produces high output. It is characterized by

(E) Effects of the invention According to the invention, by locking the internal gear and the planetary gear and rotating them together, high-speed transmission output can be obtained through the planetary gear that revolves at high speed, and also by releasing the lock. As a result, the planetary gear naturally becomes a planetary gear reduction mechanism that rotates at a low speed, and a horn for low-speed transmission is obtained.

By appropriately switching between high and low speed transmission outputs, so-called different types of torque outputs, to suit the required load on the rotated object at the start and end of rotation, a single electric screwdriver can perform a series of operations from beginning to end. It becomes a highly capable screwdriver that performs rotational operations with good work efficiency.

Moreover, since the speed can be changed only by locking and unlocking the internal gear and the propeller gear, the speed change mechanism is simple and the selection means for these speed changes can be easily provided.

(f) Examples of the invention An embodiment of the present invention will be described in detail below based on the drawings.

The drawings show an electric screwdriver, and in FIG. 1, the -c1 electric screwdriver 1 has a chuck 2 at its tip, and this chuck 2 holds various rotary tools (not shown).

The casing 3 is formed into a cylindrical shape, and is equipped with an operating tube 4 at its tip for setting a load of 1 to 1,000 liters.By rotating this operating tube 4 by C in accordance with the scale,
Set the output shaft load. A grip part 5 is connected to the intermediate lower part of the cooling sink 3, and a trigger 6 is provided on the front surface of the base of the grip part 5, and the trigger 6 is used to turn the power on and off.

A forward/reverse rotation selector switch 7 for the forward/reverse motor is provided on the side surface of the intermediate portion of the casing 3, and by operating the switch 7 in the vertical direction, the motor can be switched between forward rotation, stop, and reverse rotation. Note that since the switch 7 is internally configured in a ring shape, the switch 7 is also provided on the opposite side surface of the casing 3.

This electric screwdriver 1 uses a battery as a power source,
This battery is provided so as to be housed in the rear end of the casing 3 as appropriate.

In FIG. 2, the output of the forward/reverse motor 8 fixed in the casing 3 is connected to a first planetary gear reduction mechanism 9 equipped with variable speed outputs of high speed and low speed, and a constant speed Then, the power is transmitted to the output shaft 11 via the second, third, etc. planetary gear reduction mechanisms 10 that reduce the speed, and as a result, the chuck 2 is rotated.

Each of the reduction mechanisms 9, 10, .
The motor 8 is housed in an inner gear case 13 fixed to the inner side of the motor 8, opposite to the motor 8.

This first planetary gear reduction mechanism 9 has a first planetary gear 1 connected to a first Zang gear 15 which is rotatably attached to the end of the main shaft 14 of the motor 8.
6 are equally spaced in the circumferential direction and mesh with each other, and these first planetary gears 16 mesh with the first internal gear 17 and are allowed to revolve.

The first planetary gear 16 described above has each gear shaft connected to the first planetary gear 16.
It is fixed to the carrier 18, and the revolving output of these gears t16 is transmitted to the first carrier 18. Power is transmitted to the second planetary gear reduction mechanism 10 at the subsequent stage via an intermediate output shaft 19 that is integrated with the second planetary gear reduction mechanism 10 .

A slide gear 20 that slides in the axial direction is fitted onto the main shaft 14 of the aforementioned motor 8, and this slide gear r20
meshes with the first internal gear 17, and the first
It is provided with a recess 23 into which the protrusion 21 of the planetary shaft 2.2 is fitted, and a permanent magnet 24 and a locking protrusion 25 on the other end surface.

The above-mentioned protrusion 21 has a conical tip and serves to generate a sliding action that allows the protrusion 21 to be lightly fitted into the corresponding recess 23 and easily removed.

The above-mentioned permanent magnet 24 is integrally fitted into the exposed end surface of the central portion of the slide gear 20, and a permanent magnet 26 is similarly exposed at the boss portion 8a on the motor 8 side facing the slide gear 20. The permanent magnets 24 and 26 are separated by the magnetic repulsion of both permanent magnets 24 and 26, and the slide gear 20 is moved away from the main shaft 14 by the magnetic repulsion and the action of the magnetic circuit described later. can be slid in any direction along the .

The above-mentioned opposing permanent magnets 24 and 26 are set in a magnetic repulsion state with the same magnetic poles facing each other, so that the slide gear 20 is normally magnetically biased in a direction away from the motor 8 side, and the slide gear The protrusion 21 of the first planetary shaft 22 is fitted and locked in the end face recess 23 on the opposite side of the second planetary shaft 20, thereby locking the rotation of the first planetary gear v16. Therefore, if power is transmitted in this state, a high-speed transmission output will be obtained in which only the high-speed revolution of the first planetary gear 16 is allowed.

If you want to obtain a low-speed transmission horn, use slide gear 2.
It is installed when 0 slides and both permanent stones 24 and 26 are in contact with each other.

In this case, the locking protrusion 25 of the slide gear 20 is locked with a locking portion 27 carved on the end face on the motor 8 side, and the slide gear 20 is provided in a fixed state in which rotation is stopped, and at this time, the slide The gear 20 is unlocked from the first planetary shaft 22, allowing the first planetary gear 16 to rotate, and by transmitting power in this state, relatively low-speed transmission output can be obtained.

The above-mentioned locking protrusion 25 is provided with a spring so as to be movable forward and backward on its corresponding side, and is configured to promote a stable shock absorbing effect when it is locked with the corresponding locking portion 27.

The above-mentioned sliding operation of the slide gear 20 is performed by energizing the auxiliary coil 29 for guiding the slide gear, which is wound around the outer circumference of the boss portion 8a of the main shaft 14 via the annular frame 28. A current generated from inside the motor to be electrically connected to the main coil inside the motor is passed through the motor case 8b which is a conductor, the inner gear 1r case 13 annular frame 28, the first internal gear 17, and the slide gear 2.
A magnetic circuit is constructed that circulates around a so-called auxiliary coil 29 that flows through both the permanent magnets 24 and 26 and the boss portion 8a, and the auxiliary coil 29 is excited by the generation of this magnetic circuit.

By the way, when the auxiliary coil 29 is excited, when the load on the rotated body increases during use of the gastric driver 1 and a large current is generated in the motor 8, the magnetic repulsion of the permanent magnet A large magnetic circuit is generated to excite the auxiliary coil 29, and the slide gear 20 is slid by the excitation action of this magnetic circuit.

In addition, in the separation operation between the slide gear 20 and the boss portion 8a, it is possible to use a spring instead of a permanent magnet, but in this case, the frictional resistance at the supporting contact surfaces at both ends of the spring is high. Therefore, it is not preferable to use a permanent magnet.

Above) That second planetary gear reduction mechanism 10 has an intermediate output shaft 19
A second planetary gear 30 is pivotally connected to the second planetary gear 30, and three second planetary gears 31 are meshed with this gear and are equally spaced in the circumferential direction.
The second internal gear 3 meshes with the planetary gear 31
2, and a second carrier 34 integrated with the second planetary shaft 33
It consists of

Then, the decelerating rotational force from the intermediate output shaft 19 is further decelerated through each of these gears and the power is transmitted to the second carrier 34, and the third M star gear reduction mechanism (illustration omitted) is transmitted through the second carrier 34. ) are arranged in series so that the output shaft 11 has a predetermined deceleration rotation speed ( ).

A ball locking protrusion 35 is formed around the side surface of the second internal gear 32 facing the motor 8, and a ball 37 supported by a ball support plate 36 abuts between these protrusions 35. This ball 37 is urged toward the ball locking protrusion 35 by a spring 39 via a receiving plate 38, thereby forming a ball clutch 40.

In the ball clutch 40 described above, a torque limiter can be set by adjusting the biasing force of the spring 39.
The biasing force of the spring 39 is adjusted by adjusting the amount by which the second internal gear 32 is moved toward the ball side.

In the figure, 41, 42, and 43 are spacers, and 44 is a bearing.

FIG. 3 shows an electric circuit, in which a forward/reverse changeover switch 7 controls the forward/reverse rotation by switching the polarity of the forward/reverse motor 8. The auxiliary coil 29 is interposed between the positive side of the battery 45 and the trigger 6.

When using the tC electric screwdriver configured in this manner to tighten a bolt or nut, operate the forward/reverse selector switch 7 from the neutral stop position to the desired forward or reverse direction of rotation, and then turn the trigger 6 on. Turn on. trigger 6
When the motor 8 rotates in the forward or reverse direction due to the operation of Power is transmitted to.

At this time, in the first planetary gear reduction mechanism 9, the slide gear 20 is magnetically energized and is in the state of a high-speed transmission horn that locks the rotation of the first planetary gear 16. The fastening operation is performed under high-speed rotation conditions suitable for initial fastening, and the fastening is performed carefully.

Then, as the fastening load gradually increases, the auxiliary coil 29 is automatically excited, and the slide gear 20 slides based on the generation of a magnetic circuit. 1 planetary gear 16 is unlocked, this gear 16 is allowed to rotate, rotates at a low speed, and is switched to a sufficiently decelerated low speed, high torque transmission output. Therefore, in the tightening operation of bolts, etc., the high torque required at the end of tightening can be automatically obtained, and a rotation operation suitable for the tightening operation can be obtained with one electric screwdriver.

In the above-mentioned embodiment, the tightening operation of a rotating object such as a bolt is taken as an example, but this is not limited to the tightening operation of a rotating object such as when removing a bolt or the like, as well as other rotating objects for which torque exchange is desired. Can be applied to rotation operations. Although the once-in-a-time gear change is automatically performed by excitation of the coil, it may be configured to be changed manually.

[Brief explanation of drawings]

The drawings show one embodiment of the invention, and FIG. 1 is a side view of an electric screwdriver. Figures 2 and 2 are enlarged vertical cross-sectional views of essential parts of the transmission. FIG. 3 is its electrical circuit diagram. 1... Electric screwdriver 9... First planetary gear reduction mechanism 15... First Zang gear 16... First planetary gear 17... First internal gear 18... First carrier 20... Slide gear 22
...First planetary shaft 23...Concave portion 24.26...Permanent magnet 29...
・Auxiliary coil Fig. 2 1 Fig. 3

Claims (1)

[Scope of Claims] 1. A planetary gear reduction mechanism that includes a sun gear connected to the main shaft of the motor, a planetary gear that meshes with the sun gear, and an internal gear that meshes with the planetary gear, and extracts a variable speed output from a carrier that pivotally supports the planetary gear. A transmission device for an electric screwdriver, which locks the internal gear and the planetary gear, and generates a high-speed transmission output based on allowing their integral rotation, and unlocks the internal gear and the planetary gear. 1. A transmission device for an electric screwdriver, comprising: a selection means for selecting a low-speed transmission output based on fixing the rotation of the internal gear.