JP2002046007A - Power tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power tool having a built-in planet gear device capable of changing speed to a high speed range without rotating an internal gear to eliminate an increase in inertia and generation of vibration and noise caused by arranging a built-in type speed change gear which increases spindle speed by lowering a speed reduction ratio by rotating an internal gear integral with a carrier in a conventional manner in a motor driven drill having a built-in type planet gear type speed reduction gear for reduction the revolution of a motor for example. SOLUTION: The motor driven tool 1 has a built in type planet gear device 10 of the following specifications. A high speed constitution is provided such that a speed change member 60 is interposed between a first stage planet gear train 20 and a second stage planet gear train 40, and with this speed change member 60 displaced axially, the second stage speed reduction by means of the second stage planet gear train 40 is omitted by connecting a first stage carrier 24 and a second stage carrier 77 directly. This constitution can change speed without rotating the internal gear 73.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric tool, such as an electric drill, for reducing the rotation of an electric motor by a planetary gear unit and outputting the rotation.

[0002]

2. Description of the Related Art Heretofore, as a planetary gear device incorporated in a power tool of this type, for example, there has been a structure disclosed in Japanese Patent Application Laid-Open No. 61-90812. This conventional planetary gear device is shown in FIG. 5, which employs FIG. 2 of the publication.
As shown in the figure, the conventional planetary gear device 100 is built in an electric tool 140 driven by an electric motor 101, and includes three planetary gears sequentially connected in series from the electric motor 101 to the output shaft 102. Gear trains 110, 120,
130. Hereinafter, the first-stage planetary gear train 110, the second-stage planetary gear train 120, the third
It is referred to as a step planetary gear train 130. The first-stage sun gear 1 of the first-stage planetary gear train 110 is attached to the output shaft 101 a of the electric motor 101.
11 is attached. This first stage sun gear 111
Are meshed with first-stage planetary gears 113 to 113 attached to the first-stage carrier 112. This first
The stage planetary gears 113 to 113 are meshed with the first stage internal gear 114. The first-stage internal gear 114 is connected to the housing 1 of the power tool 140.
The gear case 142 is formed integrally with a gear case 142 attached to the inner peripheral side of the gear case 41. Therefore, the first-stage internal gear 1
14 is fixed so as not to rotate and not move in the axial direction.

The first-stage carrier 112 is formed with a second-stage sun gear 121 of a second-stage planetary gear train 120. The second-stage sun gear 121 is connected to the second-stage carrier 12.
3 are meshed with the second stage planetary gears 122 to 122 attached. This second stage planetary gear 122
122 are meshed with the second-stage internal gear 124. The second-stage internal gear 124 is installed on the inner peripheral side of the gear case 142 so as to be rotatable and movable in the axial direction (machine length direction). On the other hand, a slider 150 is attached to the side of the housing 141 so as to be movable in the axial direction, and a bracket 151 is attached to the slider 150. This bracket 151
Is inserted into an engagement groove 124 a formed over the entire outer peripheral surface of the second-stage internal gear 124. For this reason, the second-stage internal gear 124 is
In the axial direction, the slider 1
Since the slider 150 is integrated with the slider 150, the slider 150 moves forward or backward in the axial direction by the movement operation of the slider 150. However, since the rotation direction is not restricted, the slider 150 is rotatable regardless of the position of the slider 150. .

When the slider 150 is moved backward as shown in the figure, the second-stage internal gear 124 is moved backward and meshes with a meshing gear portion 142a formed on the gear case 142, so that the second stage internal gear 124 cannot rotate. On the other hand, the slider 150
When the second stage internal gear 124 is advanced by the forward operation of the second stage, the second stage internal gear 124 is disengaged from the meshing gear portion 142a and meshes with the meshing gear portion 123a formed on the second stage carrier 123.
Therefore, the second-stage internal gear 124 is rotatable with respect to the gear case 142 and the carrier 123
It becomes a state that can be rotated integrally with. Second stage carrier 123
The third stage sun gear 131 of the third stage planetary gear train 130
Are formed. The third-stage sun gear 131 has a third
Third stage planetary gear 1 attached to the stage carrier 132
33-133. The third-stage planetary gears 133 to 133 are meshed with a third-stage internal gear 134 fixed to the gear case 142. At the center of the third stage carrier 132, the power tool 14
0 output shaft 102 is fixed.

[0005] The conventional electric power tool 1 configured as described above.
According to the planetary gear device 100 of FIG. 40, the slider 150 is retracted as shown in FIG.
4 is meshed with the meshing gear portion 142a of the gear case 142, the second-stage internal gear 124 does not rotate, so the second-stage planetary gears 122 to 122 are not rotated.
Are revolved along the inner peripheral side of the second-stage internal gear 124 while rotating, whereby the rotation speed of the electric motor 101 is reduced at a constant reduction ratio and transmitted to the third-stage planetary gear train 130. Is done. Therefore, when the slider 150 is moved backward, the planetary gear device 100 switches to the low speed side. On the other hand, when the slider 150 is moved forward, the second-stage internal gear 124 engages with the gear unit 1.
42 and is engaged with the meshing gear portion 123a on the second carrier 123 side. Therefore, the second-stage internal gear 124 rotates integrally with the second-stage carrier 123. Second stage internal gear 124
Are integrated with the second-stage carrier 123, the second-stage planetary gears 122 to 122 do not rotate or revolve, so that the second-stage sun gear 131 and the second-stage carrier 123 rotate integrally to form the first-stage planetary gear. The rotation speed output from the gear train 110 is transmitted to the third-stage planetary gear train 130 without being reduced. For this reason, when the slider 150 is moved forward, the planetary gear device 100 switches to the high-speed side.

[0006]

As described above, the conventional planetary gear device 100 has a structure in which the second-stage internal gear 124 is moved in the axial direction to switch the reduction ratio thereof, thereby shifting the electric power tool 140. When the gear is switched to the high-speed side, the second-stage sun gear 121, the second-stage internal gear 124, and the second-stage carrier 123 rotate integrally. For this reason, especially when the second-stage internal gear 124 having a large diameter rotates, a large inertia is generated, and as a result, there is a problem that vibration and heat generation of the entire planetary gear train increase. This problem is remarkable in, for example, a relatively large electric drill or the like in which a 13 mm drill is mounted, and has been a particularly serious problem in this type of power tool. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a power tool having a built-in planetary gear device that generates less vibration and less heat than before.

[0007]

For this reason, the present invention provides an electric power tool having the structure described in each of the above claims. According to the power tool of the first aspect, when the speed change member is moved to the low speed side, the sun gear of the second stage planetary gear train is integrated with the carrier of the first stage planetary gear train for rotation via the speed change member. . In this state, since the rotation of the carrier of the first-stage planetary gear train is input to the second-stage planetary gear train via the sun gear,
In the second-stage planetary gear train, the planetary gears revolve around the inner peripheral side of the internal gear while rotating, whereby the rotation reduced by the first-stage planetary gear train is further reduced by the second-stage planetary gear train and output. Therefore, the output rotation speed of the planetary gear device becomes low (low-speed mode).

On the other hand, when the speed change member is moved to the high speed side, the carrier of the first stage planetary gear train and the carrier of the second stage planetary gear train are directly connected via the speed change member for rotation. The sun gear of the stage planetary gear train is rotationally disconnected from the carrier of the first stage planetary gear train. In this state, the carrier of the first-stage planetary gear train and the carrier of the second-stage planetary gear train rotate at the same rotation speed, and the rotation speed of the carrier of the second-stage planetary gear train depends on the output of the second-stage planetary gear train. Since the rotation speed of the second stage planetary gear train is not reduced, the rotation speed output from the first stage planetary gear train is output as it is as the rotation speed of the second planetary gear train. The output rotation speed of the device increases (high-speed mode). Thus, according to the power tool of the first aspect, the internal gear is not rotated integrally with the carrier as in the related art, but the high-speed mode is realized while the internal gear is fixed without being rotated. Therefore, vibration and heat generation of the planetary gear device can be suppressed as compared with the related art.

According to the power tool of the second aspect, the number of parts can be reduced as compared with a configuration in which a support shaft for supporting the transmission member is separately provided. According to the electric power tool of the third aspect, the high-speed mode and the low-speed mode can be switched by rotating the speed change dial, so that a speed change mechanism with good operability can be provided. According to the power tool of the fourth aspect, the low-speed mode and the high-speed mode can be reliably locked, and the locked state of the speed change dial can be released with a single fingertip. A good speed change mechanism can be provided.

[0010]

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. In the present embodiment, an electric drill 1 will be described as an example of a power tool. FIG. 1 shows the internal structure on the distal end side of the electric drill 1 of the present embodiment.
The illustrated electric drill 1 is a relatively large electric drill to which a drill (tip tool) having a diameter of, for example, 13 mm can be mounted, and a so-called angle type in which the drill is mounted at a right angle to the machine length direction (the left-right direction in the drawing). Electric drill. The electric drill 1 has a built-in planetary gear device 10 for reducing and outputting the rotation of an electric motor 3 as a driving source. The details of the planetary gear set 10 are shown in FIG. In FIG. 1, reference numeral 2 denotes a housing of the electric drill 1. The housing 2 has a substantially cylindrical shape, and the electric motor 3 is built in the middle in the machine length direction. The planetary gear device 10 described below is connected to the output shaft 3 a of the electric motor 3. The output of the planetary gear set 10 is further reduced by bevel gears 4 and 5. In the following description, deceleration by the bevel gears 4 and 5 is referred to as a third-stage deceleration.

The planetary gear device 10 according to the present embodiment is
The transmission has a configuration in which a transmission member 60 is interposed between the first-stage planetary gear train 20 and the second-stage planetary gear train 40. Hereinafter, the configuration of each unit will be described in detail with reference to FIG. First
The first stage sun gear 21 of the stage planetary gear train 20 is formed on the output shaft 3 a of the electric motor 3. The first stage sun gear 21 is meshed with three planetary gears 22 to 22. Each of the planetary gears 22 is
3 and rotatably supported by the first carrier 24. The three planetary gears 22 to 22 mesh with the inner peripheral side of the internal gear 25. The internal gear 25 is fixed to the housing 2 by bolts 25a to 25a.

The three support shafts 23 to 23 project from the side surface of the carrier 24 (the side surface opposite to the planetary gear 22). The transmission member 60 is attached via the protruding portions of the three support shafts 23 to 23 so as to be able to move in parallel in the machine length direction. In the following description, the transmission member 60
With respect to the moving direction of the vehicle, the front end side in the machine length direction (the right side in FIGS. 1 and 2) is referred to as a high speed side, and the rear end side in the machine length direction (the left side in FIGS. 1 and 2) is referred to as a low speed side. In the figure, the transmission member 60 that has moved to the low speed side is shown by a solid line, and the transmission member 60 that has moved to the high speed side is shown by a two-dot chain line. The speed change member 60 has a substantially annular shape, and rotates integrally with the first stage carrier 24. As shown in FIG. 3, three engagement projections 60 b to 60 b are formed on the distal end surface of the transmission member 60 at three equally-spaced positions in the circumferential direction. An engagement groove 60c is formed on the entire peripheral surface of the transmission member 60. The engagement protrusions 60b to 60b and the engagement groove 60
The function of c will be described later. A meshing tooth 60a is formed on the inner peripheral side of the speed change member 60, and a gear portion 70 formed on the first intermediate shaft 70 is formed on the meshing tooth 60a.
a is engaged. When the speed change member 60 moves to the low speed side, the meshing teeth 60a mesh with the gear portion 70a, and when the speed change member 60 moves to the high speed side, the meshing between them is released.

A rear end portion 70b of the first intermediate shaft 70 is supported coaxially with the first stage carrier 24 so as to be relatively rotatable via a needle bearing 26 attached to the center of the first stage carrier 24. A support pin 79 is attached to the front end of the first intermediate shaft 70 so as to protrude forward. This support pin 79 is inserted along the axis of the first intermediate shaft 70. The protruding portion of the support pin 79 is rotatably inserted into a support hole 95b formed along the axis of a rear end surface of a second intermediate shaft 95 described later. The support pin 79 and the needle bearing 2
6, the first intermediate shaft 70 is rotatably supported in a double-supported state.

A second intermediate shaft 70 is provided with a second end.
The second stage sun gear 71 of the stage planetary gear train 40 is formed. Three second-stage planetary gears 72 to 72 are meshed with the second-stage sun gear 71. The three second-stage planetary gears 72 to 72 are meshed with a second-stage internal gear 73. The second-stage internal gear 73 is rotatably supported by the gear case 6 attached to the front end of the housing 2. This second
Lock holes 73 a to 73 a having a V-shaped cross section are provided at an end surface of the step internal gear 73 at appropriate intervals in the circumferential direction.
Are formed. A steel ball 75 is fitted into each of the lock holes 73a to 73a. Each steel ball 75 is attached to the gear case 6.
The lock hole 7 is formed by the compression spring 76 housed in the holding hole 6a.
It is urged in a direction to fit into 3a. Therefore, the second
The step internal gear 73 is pressed against the fixed plate 7 attached to the rear end of the gear case 6 by the urging force of the steel balls 75 to 75, thereby imparting a constant rotational resistance to the second step internal gear 73. Have been. The electric drill 1
In the normal use state of the second stage internal gear 7
Since no external force greater than the rotation resistance is applied to the third internal gear 3, the second-stage internal gear 73 does not rotate with respect to the gear case 6. On the other hand, when the electric drill 1 is used, if a large rotation resistance (overload) of a certain level or more is externally applied through the mounted drill, the second-stage internal gear 73 resists the compression spring 76. As a result, the steel ball 75 is rotated while being pushed into the holding hole 6a, thereby preventing a large external resistance from returning to the electric motor 3 via the first intermediate shaft 70. In this regard, this second stage planetary gear train 4
0 has a so-called torque limiter function.

Next, three second-stage planetary gears 72 to 72
Reference numeral 72 denotes a second-stage carrier 77 via a support shaft 74.
It is supported rotatably. Each support shaft 74 is provided with the first
Contrary to the step planetary gear train 20, the second planetary gear 72 protrudes further rearward (to the left in FIG. 2) from the rear end face. A receiving member 78 is attached to the rear of the second-stage planetary gears 72 to 72 via the protruding portions. The receiving member 78 has a substantially annular shape like the transmission member 60, but does not move in the machine length direction unlike the transmission member 60. However, the receiving member 78 rotates integrally with the second carrier 77 via the support shafts 74 to 74. The receiving member 78 is provided at the rear of the transmission member 6.
0. On the rear surface of the receiving member 78, meshing recesses 78a to 78a meshing with the meshing projections 60b to 60b of the transmission member 60 are formed.
When the speed change member 60 moves to the high speed side, the engagement projections 60b to 60b are engaged with the engagement concave portions 78a to 78b of the receiving member 78.
The transmission member 60 and the receiving member 78 rotate integrally with each other. When the speed change member 60 moves to the low speed side, the meshing state of the meshing projections 60b to 60b with the meshing recesses 78a to 78a is released.

Next, a switching mechanism for switching the position of the transmission member 60 will be described. As described above, the engaging groove 6 is formed on the entire peripheral surface of the speed change member 60.
0c is formed. The forked portion 80a of the speed change bracket 80 is fitted into the engagement groove 60c over a substantially half circumference thereof. Thereby, the speed change bracket 8
The zero forked portion 80a is engaged for the movement in the machine length direction while allowing the rotation of the transmission member 60. For this reason,
As the speed change bracket 80 moves in the machine length direction, the speed change member 60 moves to the high speed side or the low speed side. The speed change bracket 80 includes a support shaft 8 attached to the housing 2.
It is supported so as to be able to move in parallel in the machine length direction via 1 and 81. Also, as shown in FIG.
Is bent in a U-shape, and a guide groove 80b long in a direction orthogonal to the machine length direction (the width direction of the electric drill 1) is formed in the bottom plate portion 80c of the bent portion. The speed change dial 90 is provided in the guide groove 80b.
The eccentric pin 91 attached to the is inserted.

The speed change dial 90 is rotatably supported on the lower surface of the housing 2 via a boss 90a formed on the upper surface thereof. The center of the boss 90a is the center of rotation of the speed change dial 90. Boss part 90a
The eccentric pin 91 is attached at a position eccentric to the rotation center by a certain dimension on the upper surface of the eccentric pin so as to protrude upward. When the speed change dial 90 is rotated, the eccentric pin 91 revolves around the rotation center of the speed change dial 90. The guide groove 80 into which the eccentric pin 91 is inserted.
Since b is elongated in the direction orthogonal to the machine length direction as described above, the displacement of the eccentric pin 91 in the same direction is released, and only the displacement in the machine length direction is transmitted to the speed change bracket 80. The bracket 80 moves in the machine length direction.

The speed change dial 90 is provided with a lock button 92 movably in the radial direction. The lock button 92 is urged radially outward by a compression spring 93. A protrusion 92 a is provided on the upper surface of the lock button 92.
Are formed. On the other hand, as shown in FIG. 4, the housing 2 is formed with a circular groove 2 a centered on the rotation center of the speed change dial 90. Lock grooves 2b and 2c are formed radially outward at two opposing positions of the circular groove 2a. When the lock button 92 is pushed in against the compression spring 93, the protrusion 92a is displaced radially inward and moves from the lock grooves 2b, 2c into the circular groove 2a, whereby the speed change dial 90 can be rotated. State. On the other hand, when the pressing operation of the lock button 92 is stopped, since the lock button 92 is urged radially outward by the compression spring 93, the speed change dial 9 is pressed.
0 is rotated to two circumferential positions (high-speed position, low-speed position), the protrusion 92a moves from the circular groove 2a to the lock grooves 2b, 2c.
And the rotation operation of the speed change dial 90 is prohibited. In a state where the rotation operation of the speed change dial 90 is prohibited, the speed change bracket 80 is locked immovably, so that the speed change member 60 is locked to the high speed side or the low speed side.

Next, meshing teeth 77a are formed on the inner peripheral side of the second stage carrier 77 of the second stage planetary gear train 40, and the meshing teeth 77a are formed with the meshing teeth 95a formed on the second intermediate shaft 95. Are always engaged. Therefore, the second intermediate shaft 95 rotates integrally with the second stage carrier 77. The second intermediate shaft 95 is rotatably supported via a bearing 96 and a needle type bearing 98. A support hole 95b is formed in the rear end surface of the second intermediate shaft 95, and a protruding portion of a support pin 79 attached to the first intermediate shaft 70 is rotatably inserted into the support hole 95b. As described above, the first intermediate shaft 70 is supported by the support pins 79 in a double-supported state. Second intermediate shaft 9
The bevel gear 4 is integrally formed on the tip side of the bevel gear 5, and the bevel gear 4 is meshed with the bevel gear 5 having a larger diameter. The bevel gear 5 is fixed to a spindle 8. The spindle 8 is rotatably supported by bearings 8a and 8b along a direction orthogonal to the machine length direction.
A chuck device 9 for mounting a drill is attached to the distal end side of the spindle 8.

According to the electric drill 1 incorporating the planetary gear device 10 configured as described above, the lock button 92 is pushed in against the compression spring 93, and the speed dial 90 is rotated in this pushed state, whereby The speed of the planetary gear device 10 can be shifted to a high speed side or a low speed side. When the projection 92a formed on the lock button 92 is located in the lock groove 2b on the left side in FIG. 4 (the state shown in FIG. 1), the eccentric pin 91 is located on the rear side in the machine length direction. The transmission member 60 is located at the lower speed side. Hereinafter, this state is referred to as a low-speed mode. In the low-speed mode, when the first-stage sun gear 21 rotates by starting the electric motor 3, the first-stage planetary gears 22 to 22 rotate. Since the first-stage planetary gears 22 to 22 are meshed with the non-rotating first-stage internal gear 25, the first-stage planetary gears 22 to 22 revolve around the inner peripheral side of the first-stage internal gear 25, thereby rotating the first-stage carrier. 24 and the speed change member 60 rotate. At this stage, deceleration by the first planetary gear train 20 is performed (first stage deceleration).

In the low speed mode, the gear portion 70a of the first intermediate shaft 70 is meshed with the meshing teeth 60a of the transmission member 60, so that the rotation of the transmission member 60 rotates the first intermediate shaft 70. When the first intermediate shaft 70 rotates, the second-stage sun gear 71 integrally formed with the first intermediate shaft 70 rotates, whereby the second-stage planetary gears 72 to 72 rotate. Second
Since the stage planetary gears 72 to 72 are meshed with the second stage internal gear 73 which does not rotate in a normal use state, the stage planetary gears 72 to 72 rotate while revolving around the inner peripheral side of the second stage internal gear 73, thereby rotating the second stage internal gear 73. The step carrier 77 and the second intermediate shaft 95 rotate. At this stage, the speed is reduced by the second planetary gear train 40 (second stage reduction). The rotation of the second intermediate shaft 95 is further reduced by the engagement of the bevel gear 4 and the bevel gear 5 and transmitted to the spindle 8 (third stage reduction). Thus, in a state where the planetary gear device 10 is switched to the low-speed mode, the first to third stages of deceleration are performed.

On the other hand, the lock button 92 is pushed in against the compression spring 93, and the speed dial 90 is rotated by about 180 ° in the pushed state.
When the lock 2a is positioned in the lock groove 2c on the right side in FIG. 4, the eccentric pin 91 is displaced to the front in the machine length direction as shown by the two-dot chain line in FIG. The transmission member 60
Is displaced to the high speed side. Hereinafter, this state is referred to as a high-speed mode.

When the speed change member 60 is displaced to the high speed side on the right side in FIG. 2 and the planetary gear device 10 enters the high speed mode, the meshing projections 60b to 60b of the speed change member 60 move to the second speed.
Meshing recess 78a of receiving member 78 of stepped planetary gear train 40
Meshing teeth 6 of the transmission member 60
0a is disengaged from the gear portion 70a of the first intermediate shaft 70, and the rotation of the transmission member 60 is not transmitted to the first intermediate shaft 70. Therefore, the first-stage carrier 24 and the receiving member 78 are integrated via the transmission member 60. Rotate with. The receiving member 78 rotates integrally with the second-stage carrier 77, and the second-stage carrier 77 engages with the meshing teeth 77a and the meshing teeth 95a to form the second carrier.
Since it rotates integrally with the intermediate shaft 95, the first-stage planetary gear train 2
The rotation output from 0 is input to the third-stage reduction gear train without being reduced by the second-stage planetary gear train 40. Therefore, in the high-speed mode, the rotation speed of the spindle 8 is higher than in the low-speed mode.

As described above, in the low-speed mode, the first to third stages of deceleration are all performed, but in the high-speed mode, the second stage of deceleration is not performed, so that the rotation speed of the spindle 8 can be switched to two stages. . Moreover, according to the planetary gear device 10 of the present embodiment, the internal gear 73 is not fixed to shift in the axial direction as in the related art, but is shifted in a fixed state with the internal gear 73 as it is. Therefore, vibration and heat generation of the planetary gear device 10 can be significantly reduced as compared with the related art. Also,
According to the illustrated planetary gear device 10, the electric drill 1
During use, when a rotation resistance (overload) of a certain level or more is externally applied through the attached drill, the second-stage internal gear 73 is pressed against the steel balls 7 against the compression springs 76 to 76.
In order to rotate while pushing the 5-75 into the holding hole 6a,
Such a large external resistance is prevented from being returned to the electric motor 3 (torque limiter function).

Various modifications can be made to the embodiment described above. For example, an eccentric pin 91 is attached to a rotary type speed dial 90 as a means for moving the speed change bracket 80, and a configuration using the displacement of the eccentric pin 91 is exemplified. However, a speed change button is provided so as to be slidable in the machine length direction. Alternatively, the shift button may be slid to displace the shift bracket directly in the machine length direction. Also, the angle type electric drill 1 is illustrated as an example of the electric tool, but the planetary gear device according to the present invention includes:
The present invention can be widely applied as a straight type electric drill or a speed reducer for other electric tools such as an impact driver.

[Brief description of the drawings]

FIG. 1 is a side view showing an internal structure of an angle type electric drill incorporating a planetary gear device according to an exemplary embodiment.

FIG. 2 is an enlarged view of the planetary gear device.

FIG. 3 is a sectional view taken along line (3)-(3) of FIG. 1;
It is the figure which looked at the speed change member from the front side.

FIG. 4 is a sectional view taken along line (4)-(4) of FIG. 1;
It is a top view of a circular groove and a lock groove.

FIG. 5 is a diagram showing a transmission mechanism of a conventional planetary gear device, which is a diagram in which FIG. 2 of JP-A-61-90812 is used.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electric drill (angle type) 2 ... Housing 2a ... Circular groove, 2b ... Lock groove (low-speed side), 2c ... Lock groove (high-speed side) 10 ... Planetary gear device 20 ... 1st stage planetary gear train 21 ... 1st Stage sun gear 22 First stage planetary gear 24 First stage carrier 25 First stage internal gear 40 Second stage planetary gear train 60 Transmission member 70 First intermediate shaft 71 Second stage sun gear 72 Second Step planetary gear 73 Second stage internal gear 77 Second stage carrier 78 Receiving member 80 Speed change bracket 90 Speed change dial 91 Eccentric pin 92 Lock button 95 Second intermediate shaft 100 Planetary gear device (conventional) 124 second stage internal gear

Claims (4)

[Claims] 1. A power tool for reducing the rotation of an electric motor by a planetary gear set and outputting the reduced power, wherein the planetary gear set has a transmission between a first stage planetary gear train and a second stage planetary gear train. And the transmission is provided with the first
A transmission member that rotates integrally with the carrier of the stepped planetary gear train and is attached so as to be relatively movable in the axial direction, and moves the transmission member to a low-speed side separated from the carrier of the second stage planetary gear train. Then, the sun gear of the second-stage planetary gear train is integrated with the carrier of the first-stage planetary gear train for rotation via the transmission member, and the transmission member is moved to the second planetary gear train.
When the carrier of the first stage planetary gear train is moved to the high speed side approaching the carrier of the stage planetary gear train, the carrier of the first stage planetary gear train and the carrier of the second stage planetary gear train are integrated in rotation via the speed change member, A power tool having a configuration in which a sun gear of the second-stage planetary gear train is rotatably separated from a carrier of the first-stage planetary gear train. 2. The power tool according to claim 1, wherein
An electric power tool in a stepped planetary gear train, wherein a transmission member is supported so as to be non-rotatable and axially movable with respect to the carrier by using a support shaft rotatably supporting a planetary gear to a carrier. 3. The power tool according to claim 1, wherein a speed change dial is rotatably provided on the housing, and an eccentric pin is provided at a position of the speed change dial eccentric from a rotation center of the speed change dial, and the housing is provided with the eccentric pin. The bracket is provided so as to be movable in the same direction as the moving direction of the speed change member, the bracket is provided with a long engaging groove in a direction orthogonal to the moving direction of the speed changing member, and the eccentric pin is inserted into the engaging groove. An electric tool having a configuration in which the bracket is moved by the displacement of the eccentric pin accompanying rotation of the speed change dial to move the speed change member to a high speed side or a low speed side. 4. The power tool according to claim 3, wherein a lock button is provided on the speed change dial so as to be movable in the radial direction and spring-biased radially outward, and the lock button is directed toward the side surface of the housing. While the protrusion is provided, a circular groove is formed on the side surface of the housing, and a lock groove is cut radially outward at two opposite positions of the circular groove, and in a state where the protrusion is positioned in the lock groove, the speed change dial is turned. A power tool which is not rotatable and has a configuration in which the lock button is moved against a spring urging force to position the protrusion in the circular groove and rotate the speed change dial.