JPH0630328Y2 - Switching device for a speed change mechanism in a power tool - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a switching device for switching the output rotation speed of a speed change mechanism in an electric power tool.

(Prior Art) As a conventional technology, there is, for example, JP-A-58-59710.

(Problems to be solved by the invention) The problem that the mechanism of the conventional transmission mechanism switching mechanism is complicated and the number of parts increases, and the gear switching device is damaged when switching operation is performed during rotation of the transmission mechanism. There was a problem.

The present invention aims to solve the above problems.

(Means for Solving the Problems) The present invention includes two transmission gear systems each having a sun gear, a planetary gear, and an internal gear, and both sun gears of both transmission gear systems are rotatably coupled and input. The planetary gear on the output side is pivotally attached to the internal gear on the output side, and the revolution number of the planetary gear on the output side is switched depending on whether the internal gear on the output side is rotating or stopped. In a power tool having a speed change mechanism configured to have a plurality of gears, the power tool includes a stopper that selectively engages one of the internal gears and restricts a rotational operation of the engaged internal gear, and the switching A slider supported slidably in the same direction as the sliding direction of the lever is provided in parallel, and when the switching lever is slid in a spring groove formed in the slider. A structure is provided in which a spring installed between both of the projecting pieces is inserted so as to be pressed in the sliding direction and compressed by one projecting piece of the pair of projecting pieces provided at both ends of the switching lever. Have.

(Operation) In the switching device for the speed change mechanism having the above-mentioned configuration, when one of the input-side and output-side internal gears is selectively stopped to switch the revolution speed and output speed of the output-side planetary gear When a switching lever having a pair of protrusions for pressing the springs inserted in the spring grooves of the slider is slid in the direction in which the two internal gears of the speed change mechanism are arranged, the spring causes one of the protrusions to move. Is pressed in the sliding direction of the switching lever to compress, and the slide pressed by this spring slides in the sliding direction of the switching lever later than the switching lever, and the stopper of the slide acts as an internal gear on the sliding direction side. Due to the elastic engagement, the rotational movement of the internal gear is naturally prevented.

(Embodiment) Next, an embodiment of the present invention applied to an electric drill will be described with reference to FIGS. 1 to 4.

A motor 2 housed in the upper part of the housing 1 of the electric drill is a battery 3 housed in the lower part of the housing 1.
The motor 2 is rotationally driven in the forward and reverse directions, and the rotation direction of the motor 2 is switched by the forward / reverse switch 4.

In the speed change mechanism H in which three series of transmission gear systems G1, G2, G3 are arranged, the first sun gear 5 of the first transmission gear system G1.
Is fitted to the motor shaft 2a of the motor 2 serving as an input shaft, while the first sun gear 5 is fitted internally to the rear end of the gear case 7 fitted near the front end in the housing 1. The internal gear 6 has a gear case cover 8 in which an engaging recess formed in a rear end surface of the internal gear 6 is attached to a front end surface of the motor 2.
It is fixed to the gear case cover 8 so as not to rotate freely by meshing with the engaging protrusions provided on the gear case cover 8.

The first planetary gears 9 to 9 meshed with the first sun gear 5 and the first internal gear 6 are concentrically arranged in front of the first sun gear 5 in order to output the revolution operation of the first planetary gear 9. The carrier 10 is rotatably and revolvably supported via the support shaft 10a, and the first planetary gear 9 revolves to rotate the carrier 10 at a constant speed.

The second sun gear 11 of the second transmission gear system G2 is the carrier 10
The third sun gear 12 of the third transmission gear system G3 has the same number of teeth as the second sun gear 11, and is integrally connected to the front of the second sun gear 11 in a concentric manner. .

The second internal gear 13 of the second transmission gear system G2 is rotatably fitted so as to face the second sun gear 11 in the vicinity of the central portion of the gear case 7 so as to face the ring 14 in front of the first internal gear 6. Rear engaging grooves 13a to 13a, which are recessed along the circumferential direction, are arranged at equal intervals on the front portion of the outer peripheral surface of the rear engaging grooves.

The third internal gear 15 of the third transmission gear system G3 is rotatably fitted so as to face the third sun gear 12 in the vicinity of the front end of the gear case 7 and is adjacent to the front of the second internal gear 13. Front engaging grooves 15a, which are arranged side by side and are arranged at equal intervals with the rear engaging grooves 13a of the second internal gear 13 at equal intervals, are provided near the center of the outer peripheral surface thereof.
A flat portion 15b aligned with the bottom surfaces of the front and rear engagement grooves 15a and 13a is formed over the entire periphery at the rear portion of the outer peripheral surface thereof so as to be interposed between the front and rear engagement grooves 15a and 13a.

The second planetary gears 16 to 16 of the second transmission gear system G2, which are meshed with the second sun gear 11 and the second internal gear 13 so as to rotate and revolve, project on the rear end surface of the third internal gear 15. Spindle 1 installed and arranged in a planetary pattern
5c are respectively fitted and connected to the third internal gear 15, and when the rotational operation of the second internal gear 13 is regulated, the second sun gear 11 revolves to drive the third internal gear 15 to rotate. To be done.

The third planetary gears 17 to 17 of the third transmission gear system G3, which are meshed with the third sun gear 12 and the third internal gear 15 so as to be capable of rotating and revolving, project on the rear end surface of the spindle 25 serving as an output shaft. The support shafts 25a arranged and arranged in a planetary pattern are fitted into the support shafts 25a and linked to the spindle 25 to restrict the rotational movement of the third internal gear 15 and release the rotational restriction of the second internal gear 13. When this occurs, the third planetary gear 17 revolves with the rotation of the third sun gear 12, the spindle 25 decelerates and rotates at the revolution number of the third planetary gear 17, and the rotation of the second internal gear 13 is restricted and When the rotation restriction of the internal gear 15 is released, the second planetary gear 16 revolves by the rotation of the second sun gear 11, and the third planetary gear 17 rotates the third internal gear 15. And the rotation of the third sun gear 12 are transmitted to the third planetary gear 17, and the third planetary gear 17 revolves at a rotational speed that is higher than the rotational speed of the third internal gear 15 such as the rotation restriction. Spindle 2 in revolutions
5 is rotated at variable speed.

The rotation operation of the second internal gear 13 or the third
A switching lever 18 provided for restricting one of the rotational movements of the internal gear 15 is provided so as to be slidable in the front-rear direction with respect to the vicinity of the lower end of the front portion of the housing 1, and protrudes near the front-end of the upper surface thereof. The coil spring 19 is narrowed between the pair of front and rear projecting pieces 18a, 18a, and both ends thereof are held by the projecting pieces 18a. On the outer wall surface of the side piece 18b projecting on one side thereof. The bent portion of the leaf spring 20 which is interposed between the side piece 18b and the housing 1 and is bent into a substantially V-shape is elastically engaged so that the switching lever 1
Locking portions 21 and 21, which are respectively recessed to lock 8 at the front end or the rear end, are arranged side by side in front and rear,
Further, a knob 18c that is partially exposed to the outside of the housing 1 for slidingly operating the switching lever 18 is provided on the lower surface thereof.
Is projected.

The slider 22 mounted in parallel on the switching lever 18 has a slide groove 2 which is recessed along the front-rear direction with respect to the central portion of the lower end thereof.
Both projections 18a of the switching lever 18 are fitted into the switching lever 2a and are connected to the switching lever 18 so as to be slidable in the front-rear direction. For this reason, the spring groove 23 has a length that is substantially equal to the distance between the two protruding pieces 18a and that is slightly expanded.
On the other hand, on the upper surface of the slider 22, a flat portion 15b which is in a neutral position with respect to the rear engagement groove 13a of the second internal gear 13 and the front engagement groove 15a of the third internal gear 15 is formed. To selectively engage with each other to regulate one of the rotation of the second internal gear 13 and the rotation of the third internal gear 15, and a through-hole having a long hole penetrating the lower end of the gear case 7. Stopper 2 inserted in 7a
When the switching lever 18 is slid forward or backward, the coil spring 19 is pressed by the projection 18a on the side opposite to the moving direction of the switching lever 18 and compressed, and the slider 22 is compressed. The repulsive force of 19 pushes the switch lever 18 in the moving direction to move it forward or backward, and the stopper 24 elastically engages with the front engaging groove 15a that is rotating from the rear engaging groove 13a through the flat portion 15b. Or from the front engaging groove 15a to the flat portion 15
The rotation of the second internal gear 13 or the rotation of the third internal gear 15 is restricted by the elastic engagement with the rotating rear engagement groove 15a via b, and the spindle 25 moves at a low speed. The number of rotations of the chuck 26 fixed to the tip of the spindle 25 by rotating or rotating at high speed, and the number of rotations of the drill bit inserted in the chuck 26 is 2
It is possible to shift in steps.

Next, the operation and effect of the embodiment having the above configuration will be described.

In this example, two transmission gear systems G2, G3 each having a sun gear 11, 12, a planetary gear 16, 17 and an internal gear 13, 15 are provided, and both transmission gear systems G2, G2 are provided.
Both G3 sun gears 11 and 12 are rotatably coupled to each other, the input side planetary gear 16 is pivotally attached to the output side internal gear 15, and the output side internal gear 15 is rotated and stopped. In the electric power tool having the speed change mechanism in which the revolution number of the planetary gear 17 on the output side is switched by this so that the revolution number becomes the output revolution number, the both internal gears 13 and 15 slide in the arrangement direction. A switching lever 18 operably supported and a stopper 24 that selectively engages one of the internal gears 13 and 15 to restrict the rotational movement of the internal gears 13 and 15 that are engaged are provided. A slider 22 supported so as to be slidable in the same direction as the sliding direction of the lever 18 is provided in parallel, and a switching lever 18 is provided in a spring groove 23 formed in the slider 22. It is installed between both projecting pieces 18a so as to be pressed in the sliding direction and compressed by one projecting piece 18a of a pair of projecting pieces 18a projecting at both ends of the switching lever 18 when the ride operation is performed. A spring 19 is inserted.

Therefore, the retracting operation of the stopper 24 from both the engaging grooves 13a and 15a and the engaging operation into the engaging grooves 13a and 15a are performed without difficulty, and the switching operation of the output rotation speed of the speed change mechanism H is smoothly performed. In addition, the pressing force for controlling the forward / backward movement of the slider 22 can be ensured by the retracting operation of one spring, and the switching mechanism can be simplified and the number of parts can be reduced.

In addition, in this example, the stopper 24 has both the engaging grooves 13a and 15a.
The flat portion 15b during the transition when engaging with the
Since both of the engaging grooves 13a, 1 of the stopper 24 are provided,
It is possible to suppress a problem that the retracting operation and the engaging operation with respect to 5a are separated in the middle of the transition, both rotating members linked to the stopper 24 rotate synchronously, and the stopper 24 and both rotating members are damaged early.

Further, when the switch is operated to rotate the transmission mechanism H at the time of switching the rotation speed, the stopper 24 is automatically engaged with one of the front and rear engagement grooves 13a and 15a by the repulsive force of the coil spring 19 by the sliding operation of the switching lever 18. Therefore, the switching operation can be simplified, and the stopper 24 can be smoothly displaced even during rotation of the speed change mechanism H to easily switch the rotation speed.

(Effects of the Invention) With the configuration of the present invention as described above, the stopper and the internal gear can be smoothly engaged with each other during the rotation of the internal gear, and the internal gear can be stopped without difficulty.

In addition, the output speed is switched by using the internal gear of the speed change mechanism with a planetary gear, and the slider stopper is directly engaged with and disengaged from the internal gear to change the speed. Therefore, the switching mechanism can be simplified and made compact. The space occupied by the mechanism can be reduced,
The setting range of the gear ratio can be expanded.

Further, since the pressing force is applied to the slider by one spring to move the slider, the switching mechanism can be simplified and the number of parts of the switching mechanism can be reduced.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a cutaway side view of a main part of an electric power tool, and FIGS. 2 (a) and 2 (b) are side cross-sections of the main part for explaining the operation of a switching mechanism. Figures and 3 are XX of Figure 1.
4 is an exploded perspective view of the switching mechanism. 18 ... Switching lever 19 ... Coil spring 22 ... Slider 24 ... Stopper H ... Transmission mechanism

Claims (1)

[Scope of utility model registration request] 1. A transmission gear system comprising a sun gear, a planetary gear and an internal gear, wherein both sun gears of the two transmission gear systems are rotatably coupled to each other and the planetary gear on the input side is connected to the output side. It is pivotally attached to the internal gear, and the revolution number of the output side planetary gear is switched depending on whether the output side internal gear is rotating or stopped, and this revolution number becomes the output revolution number. In a power tool having a speed change mechanism, a switching lever supported so as to be slidable in the arrangement direction of the both internal gears,
A slider having a stopper that selectively engages with one of the internal gears to restrict the rotational movement of the engaged internal gear, and is slidably supported in the same direction as the sliding direction of the switching lever; Are arranged side by side, and when the switching lever is slid in a spring groove formed in the slider, one of the pair of projecting pieces projecting at both ends of the switching lever slides in the sliding direction. A switching device for a speed change mechanism, comprising a spring installed between the projecting pieces so as to be pressed and compressed.