JP4132005B2 - Electric tool - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric tool such as a driver drill in which a planetary gear reduction mechanism is disposed between a motor and a spindle.
[0002]
[Prior art]
In a power tool such as a driver drill, a planetary gear speed reduction mechanism is provided between an output shaft of a motor and a spindle that are arranged coaxially. This planetary gear speed reduction mechanism is formed by connecting a plurality of carriers supporting a plurality of planetary gears meshed in an internal gear in the gear case in the axial direction so as to mesh at the center of the planetary gear of the next stage, By attaching the gear case to the motor, the pinion of the output shaft meshes with the center of the first stage planetary gear. The spindle is connected to the last stage carrier.
[0003]
Further, here, the one internal gear is provided so as to be rotatable and movable in the axial direction, while the one internal gear is slid in conjunction with a slide operation of a switching member provided outside the outer housing. An interlocking member is provided, and by operating the switching member, the internal gear is simultaneously meshed with the carrier and the planetary gear meshed at the next stage to reduce the number of speed reduction stages, and the slide position for obtaining high-speed rotation, and the internal gear as a gear case. In some cases, a speed switching mechanism is used that is engaged with the inner surface of the motor and restricts rotation, and that can be switched to a slide position that is engaged with only the planetary gear to return the number of stages of deceleration to rotate at a low speed. For example, in the utility model registration No. 2585716, a pin provided at the lower end is provided on the outer surface of the gear case with a semi-arc-shaped shift arm (interlocking member) that engages with the internal gear through the gear case. By connecting the protrusion provided on the upper end of the arm into the groove of the shift knob (switching member) provided slidably on the outer surface of the housing via a spring, the shift arm is slid in the axial direction by operating the shift knob. A mechanism is disclosed in which a null gear can be slid.
[0004]
[Problems to be solved by the invention]
In the above speed switching mechanism, the internal gear is connected to the shift arm (interlocking member) provided outside the gear case through the gear case. Therefore, it is necessary to provide a through hole in the gear case, and grease leaks from the inside. On the other hand, the dust that has entered the housing further enters the gear case, thereby deteriorating the slidability of the internal gear.
Further, if the space between the gear case and the housing is large, the pin of the shift arm provided between them may be disengaged from the internal gear, resulting in lack of reliability.
[0005]
Therefore, the invention according to claim 1 provides an electric tool that is excellent in reliability because it can reliably slide the internal gear in addition to the possibility of grease leakage and dust intrusion in the gear case. It is intended to do.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is characterized in that the interlocking member is located between the inner peripheral surface of the gear case and the outer peripheral surface of the one internal gear in the gear case, and the axial direction of the internal gear of the one internal gear. And a pin projecting from the inner periphery of the slide ring toward the shaft center is inserted into a recessed groove provided on the outer periphery of one internal gear. One of the connecting projections projecting from the upper end of the slide ring is connected to the switching member through a long groove formed in the gear case, and either the outer peripheral surface of the slide ring or the inner peripheral surface of the gear case the protrusion, the guide groove protrusion is fitted into the other, the upper increases arranged in cross section of the gear case, characterized in that a plurality provided along the axial direction of the respective slide ring Than is.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a partial cross-sectional explanatory view of a driver drill 1 as an example of an electric tool. The battery pack 5 is detachably attached to the lower end of the handle 3 that includes the DC motor 4 and extends below the main body housing 2. A switch (not shown) that is electrically connected when the battery pack 5 is mounted is built in the handle 3, and the DC motor 4 is driven by pushing the switch lever 6 provided on the handle 3.
Further, a unit 7 shown in FIG. 2 is arranged in front of the DC motor 4. This unit 7 includes a planetary gear speed reduction mechanism 10 in the rear first gear case 8, a torque adjustment mechanism 11 in the front second gear case 9, and the rear surface of the first gear case 8 screwed to the front surface of the DC motor 4. On the other hand, the change ring 38 of the torque adjustment mechanism 11 is rotatably held at the front end of the main body housing 2 so that the torque adjustment mechanism 11 is assembled to the main body housing 2.
[0008]
The planetary gear reduction mechanism 10 includes carriers 13, 14, 15 that support three planetary gears 12, 12,... In the cylindrical first gear case 8, respectively, and planetary gears 12, 12,. .. Three stages are connected in the axial direction so as to mesh with each other at the center of the shaft. When the unit 7 is assembled, the pinion of the output shaft 4a of the DC motor 4 meshes with the center of the first stage planetary gears 12, 12,. The spindle 16 is coaxially splined to the third stage carrier 15.
In the first gear case 8, the planetary gears 12, 12... At each stage mesh with the inner circumferences of the ring-shaped internal gears 17, 18, 19 and revolve, respectively. The internal gear 18 is accommodated in the first gear case 8 so as to be rotatable and movable in the axial direction, and teeth 20, 20... Provided on the inner peripheral surface of the first gear case 8 are disposed on the outer periphery thereof. ··· and engagement grooves 21, 21,..., And a recessed groove 22 having a ring shape in the circumferential direction behind the engagement teeth 21. That is, the internal gear 18 meshes with the teeth 20, 20,... Of the first gear case 8 in the state of meshing with the second stage planetary gears 12, 12,. In the retracted position, the gears mesh with the teeth 23, 23,... Provided on the outer periphery of the first-stage carrier 13 while meshing with the second-stage planetary gears 12, 12,.
[0009]
As shown in FIG. 3, a slide ring 24 as an interlocking member is externally mounted on the outer periphery of the internal gear 18 in the first gear case 8 so as to be movable in the axial direction. The slide ring 24 has a pair of headed pins 25, 25 penetrating from the outer periphery toward the axial center at left and right point-symmetrical positions, and the tip of each headed pin 25 is formed in the concave groove 22 of the internal gear 18. (In FIGS. 1, 2 and 4, for the purpose of explaining the inserted state of the headed pin 25, it is displayed below the slide ring 24 for the sake of convenience.) 24 and the internal gear 18 are integrally moved in the axial direction. In addition, since the inner peripheral surface of the first gear case 8 is close to the outside of the head portion 26 of each head pin 25, the head pin 25 is prevented from coming off outward.
Further, on the outer periphery of the slide ring 24, three protrusions 27, 27,... Projected in the axial direction are arranged at equal intervals (however, two of the protrusions are arranged in the upper half). .. Are fitted into guide grooves 28, 28,... Recessed at corresponding positions on the inner peripheral surface of the first gear case 8. Due to the fitting between the projection 27 and the guide groove 28, the slide ring 24 is restricted from rotating in the first gear case 8 and is guided to slide in the axial direction.
Further, a connecting projection 29 is provided in the axial direction slightly behind the upper end of the slide ring 24, and protrudes from the long groove 30 formed at the upper end of the first gear case 8 to the outside of the first gear case 8. A speed changeover switch 31 as a changeover member is provided above the main body housing 2 so as to be movable back and forth in the axial direction, and the connecting protrusion 29 is a coil spring 32, 32 housed in the speed changeover switch 31. It is elastically connected with a shape sandwiched between.
[0010]
On the other hand, in the torque adjustment mechanism 11, an internal gear 19 that meshes with the third stage planetary gears 12, 12... Is rotatably provided in the second gear case 9, and in front of the internal gear 19, Balls 33 and 33, and a washer 35 that is fitted onto a cylindrical portion 34 that supports the spindle 16 in front of the second gear case 9 are provided. On the other hand, a slide sleeve 36 is screwed into the cylindrical portion 34 and a coil spring 37 is disposed between the cylindrical sleeve 34 and the washer 35. The slide sleeve 36 is moved by rotating the change ring 38 that is integrated only with the slide sleeve 36. By screw feeding in the axial direction and changing the pressing force applied to the internal gear 19 by the coil spring 37, when a load exceeding the pressing force is applied to the spindle 16, the internal gear 19 is idled to transmit torque. It is designed to shut off (driver mode). At the screw feed position where the slide sleeve 36 abuts against the washer 35, since the elasticity by the coil spring 37 does not work, the internal gear 19 is prevented from idling even if a large load is applied, and the rotation transmission to the spindle 16 is continued. (Drill mode). Reference numeral 39 denotes a drill chuck attached to the tip of the spindle 16.
[0011]
In the driver drill 1 configured as described above, when the DC motor 4 is driven by operating the switch lever 6, the rotation of the output shaft 4a is decelerated by the planetary gear reduction mechanism 10 and transmitted to the spindle 16. Here, When the speed changeover switch 31 is slid forward, the slide ring 24 connected via the connection protrusion 29 also moves forward as shown in FIG. 2, and further connected internally via the headed pins 25, 25. The gear 18 is moved forward. Then, the engaging teeth 21, 21... On the outer periphery of the internal gear 18 engage with the teeth 20, 20. Therefore, in this case, the rotation reduced by the first stage planetary gears 12, 12,... And the carrier 13 is sequentially reduced by the second stage, the third planetary gears 12, 12,. The spindle 16 rotates at a low speed (low speed mode). Since the connecting protrusion 29 is elastically connected to the speed change switch 31 by the coil springs 32, 32, the speed change switch 31 can be slid even if the engagement teeth 21 and the teeth 20 are not first engaged. While permitting, the slide ring 24 and the internal gear 18 are urged forward, and when the DC motor 4 is driven, the internal gear 18 is slightly rotated so that they are immediately engaged.
[0012]
On the other hand, when the speed changeover switch 31 is slid rearward, the slide ring 24 moves backward and the internal gear 18 moves backward as shown in FIG. Then, since the inner periphery of the internal gear 18 is meshed with the first stage carrier 13 while meshing with the second stage planetary gears 12, 12... The rotation of the shaft 4a is decelerated in two stages by the first stage planetary gears 12, 12,... And the carrier 13 and the third stage planetary gears 12, 12, .. and the carrier 15, and the spindle 16 rotates at a high speed. (Fast mode).
[0013]
As described above, according to the embodiment, the interlocking member that slides the internal gear 18 is located in the first gear case 8 between the inner peripheral surface of the first gear case 8 and the outer peripheral surface of the internal gear 18. Since the slide ring 24 is provided so as to be slidable in the axial direction and is connected to the internal gear 18, only one portion of the long groove 30 is provided in the first gear case 8. Therefore, there is no possibility that grease leaks from the inside or that the dust that has entered the main body housing 2 further enters the first gear case 8, and the suitable sliding property between the slide ring 24 and the internal gear 18 is eliminated. Is maintained. Further, since the headed pins 25 and 25 are prevented from coming off at the inner peripheral surface of the first gear case 8, the headed pins 25 and 25 are not likely to escape from the concave groove 22 of the internal gear 18, and the The null gear 18 can be reliably slid and excellent in reliability. In addition, since the distance between the slide ring 24 and the internal gear 18 is reduced, the size of the headed pin 25 can be shorter than that of the conventional structure connected to the internal gear from outside the gear case. The strength of the pin with pin is ensured and the durability is improved.
[0014]
The interlock member is a slide ring 24 of the ring body, and the three protrusions 27 and the guide groove 28 that are fitted to each other between the inner peripheral surface of the first gear case 8 and the slide ring 24 are respectively formed on the slide ring 24. By providing in the axial direction, the slidability of the slide ring 24 can be further enhanced. In particular, here, since two of the three protrusions 27 and the guide groove 28 are arranged on the upper side (the connection protrusion 29 side), the upper side is likely to be inclined when the connection protrusion 29 is slid at one position. Can be guided in a balanced manner.
[0015]
In the slide ring, the number of protrusions and guide grooves can be increased, or the guide grooves can be provided in the slide ring and the protrusions can be provided in the first gear case, respectively, contrary to the above configuration.
Further, instead of the headed pin, the pin may be integrally provided on the inner peripheral surface of the slide ring. In this case, as described above, since the distance from the internal gear is reduced and the strength can be secured, there is no problem in durability even with a synthetic resin.
[0016]
【The invention's effect】
According to the first aspect of the present invention, the interlocking member is provided in the gear case between the inner peripheral surface of the gear case and the outer peripheral surface of the one internal gear so as to be slidable in the axial direction of the one internal gear. And a pin projecting from the inner periphery of the slide ring toward the shaft center is inserted into a concave groove provided on the outer periphery of one internal gear and connected to the one internal gear. Then, one connecting protrusion projecting from the upper end of the slide ring is connected to the switching member through a long groove formed in the gear case, while a protrusion is provided on one of the outer peripheral surface of the slide ring and the inner peripheral surface of the gear case, and the other the guide groove protrusion is fitted, in becomes large upper arranged in cross section of the gear case along the axial direction of the respective slide ring that has plurality, or leaks grease from the inside, opposite Dust that enters into the body housing there is no possible entering further into the gear case, a suitable sliding resistance between the slide ring and the internal gear is maintained. Further, there is no possibility that the pin will come off the internal gear, and the internal gear can be reliably slid and excellent in reliability. Further, since the distance between the slide ring and the internal gear is reduced, the dimensions of the pin can be shortened, so that the strength of the pin is ensured and the durability is improved.
Further, the arrangement form of the protrusion and the guide groove makes it possible to guide the upper side where the inclination is likely to occur when the sliding operation is performed at one position of the connection protrusion in a well-balanced manner, and to further improve the sliding performance of the slide ring.
[Brief description of the drawings]
FIG. 1 is an overall explanatory view of a driver drill.
FIG. 2 is an enlarged cross-sectional explanatory view of a unit in a low-speed mode (the upper part shows a partial plane in the vicinity of a connecting protrusion).
FIG. 3 is an enlarged cross-sectional explanatory view of a first gear case.
FIG. 4 is an enlarged cross-sectional explanatory view of a unit in a high-speed mode (the upper part shows a partial plane near a connection protrusion).
[Explanation of symbols]
1 .... driver drill, 2 .... main body housing, 4 .... DC motor, 7 .... unit, 8 .... first gear case, 9 .... second gear case, 10 .... planetary gear reduction mechanism, 11 .... torque adjustment Mechanism, 16 ... Spindle, 17-19 ... Internal gear, 24 ... Slide ring, 25 ... Pin with head, 31 ... Speed switch.

Claims (1)

A planetary gear comprising a plurality of planetary gears housed in a gear case and revolving in an internal gear, and a carrier for supporting these planetary gears, between a motor and a spindle provided in the main body housing. A gear reduction mechanism is provided, and one of the internal gears is provided so as to be rotatable in the gear case and slidable in the axial direction, and in conjunction with the operation of a switching member provided outside the main body housing. An electric tool that is capable of changing the rotation speed of the spindle by changing the gear ratio by selecting the slide position of the internal gear,
The interlocking member is a slide ring provided between the inner peripheral surface of the gear case and the outer peripheral surface of the first internal gear in the gear case so as to be slidable in the axial direction of the first internal gear. The pin projecting from the inner periphery of the slide ring toward the axial center is inserted into a recessed groove provided on the outer periphery of the one internal gear to be connected to the first internal gear, and the slide while connecting the ring upper end one of the coupling protrusions projecting from the of the switching member through a long groove formed in the gear case,
A protrusion is formed on one of the outer peripheral surface of the slide ring and the inner peripheral surface of the gear case, and a guide groove into which the protrusion is fitted is arranged on the other side. A power tool provided with a plurality along the axial direction of the slide ring .

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