JPH0679637A - Torque clutch coupled rotary tool with motor-off mechanism - Google Patents

Abstract

PURPOSE:To secure the following performance of a sensor member, and improve the efficiency of the screw fastening work by adding a decelerating mechanism between an output shaft of a driving motor and a clutch and an accelerating mechanism between the clutch and a main spindle. CONSTITUTION:Since the number of revolution of a second gear 47 is restricted low by a decelerating mechanism C, a sensor member can follow the displacement of a pin 52. Since the number of revolution of a main spindle 91 is sufficiently increased by an accelerating mechanism B, speed-up of the screw fastening work is enabled. Small screws can be therefore fastened in order to enable the speed-up of the work. When the number of revolution of the main spindle 91 is increased, the fastening torque is lowered with the increase of the number of rotation of the main spindle 91, but is this rotary tool, in addition to the increase of the number of revolution of the main spindle 91, since the accelerating mechanism B is rotated with the main spindle 91 when a clutch A starts the idle rotation, practical moment of inertia of the main spindle 91 or a bit 99 is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary tool with a tightening torque management mechanism.

[0002]

2. Description of the Related Art A rotary tool for tightening screws is known in which a tightening force management mechanism is incorporated.
This tool incorporates a clutch that rotates between a main shaft that rotates a bit and an output shaft of a drive motor that idles when an excessive torque acts. When this clutch is assembled, when the screw is tightened and a certain tightening force is reached, the clutch loosely rotates and further tightening is prevented. It is also known that this tool further includes means for stopping the power supply to the drive motor. With this tool,
A kind of switch means for detecting the clutch idling phenomenon is provided, and this switch stops the energization of the motor at the same time as the clutch idling. According to this tool, even if the operator continuously turns on the operation switch,
The motor is stopped at the same time when the screw tightening is completed.

[0003]

For this reason, the conventional tool is provided with a sensor member which is displaced at the position adjacent to the clutch when the idle phenomenon occurs. At this time, if the clutch before idling rotates at high speed, the followability of the sensor member deteriorates, and the sensor member is not likely to be displaced even when the clutch starts idling. Therefore, in the conventional tool, a speed reducing mechanism is added between the output shaft of the motor and the clutch so that the rotational speed of the clutch is sufficiently low, that is, the sensor member can ensure sufficient followability. And the main shaft is directly connected to the clutch. Therefore, in the conventional tool, the rotation speed of the main shaft cannot be increased to such an extent that the followability of the sensor member is impaired, and the work efficiency is not necessarily good.

For example, in the case of a tool for tightening small screws that can be tightened with a light torque, even if there is a margin to rotate at a higher speed due to the capacity of the drive motor, the speed can be increased only within a range in which the followability of the sensor member can be secured. Can not be converted. At present, efforts are being made to improve the rotational speed of the clutch and main shaft by adjusting the reduction ratio of the reduction mechanism and improving the followability of the sensor member. If the rotation is used, the followability of the sensor member cannot be guaranteed. Therefore, in the present invention, a new technique has been developed which can increase the speed of the spindle rotation in proportion to the motor capacity and also ensure the followability of the sensor member.

[0005]

To this end, according to the present invention, a clutch is added between the main shaft on which the bit is mounted and the output shaft of the drive motor for rotating the main shaft when the excessive torque acts on the main shaft. In a rotary tool incorporating a mechanism for stopping power supply to the drive motor when the clutch starts to rotate freely, a reduction mechanism is added between the output shaft of the drive motor and the clutch, and A rotary tool with a torque clutch interlocking motor-off mechanism, which is characterized by adding a speed increasing mechanism between the clutch and the main shaft, has been created.

[0006]

According to the structure of the present invention, the speed of the clutch is reduced by the reduction mechanism, so that the followability of the sensor member can be secured. Further, since the spindle speed is increased by the speed increasing mechanism, the efficiency of the screw tightening work can be improved.

[0007]

According to the present invention, when the rotation speed of the motor is reduced and then the spindle is rotated, the speed is greatly reduced first, and then the speed is increased. However, in this case, since the speed of the main shaft is increased by the speed increasing mechanism, the clutch rotational speed can be lowered regardless of the main shaft rotational speed. Therefore, the followability of the sensor member can be secured. On the other hand, even if the clutch speed is lowered,
The spindle speed can be increased by adjusting the speed increasing ratio of the speed increasing mechanism. Therefore, according to the present invention, the followability of the sensor member can be ensured, and at the same time, the spindle speed can be matched with the motor capacity, and the degree of freedom in designing the tool can be significantly improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will specifically describe one embodiment embodying the present invention with reference to the drawings. FIG. 1 shows an embodiment in which the present invention is applied to a cordless electric tool 72, and a handle housing 71 for accommodating a battery 70 and an upper housing 73 are integrally housed in a housing integrally formed. An electric motor 74 for driving a tool is housed in the rear portion of the upper housing 73. A first gear 76 is fixed to the output shaft 75 of the electric motor 74. First gear 7
A second gear 47 meshes with the gear 6. The first gear 76 and the second gear 47 form a reduction mechanism C. Second
The gear 47 is rotatable around the intermediate shaft 44.

The intermediate shaft 44 is rotatably supported by a bearing 45 and a bearing 102. Gear teeth 44b are provided on the outer periphery of the left end portion in the figure, an enlarged diameter portion 44c is provided on the right side thereof (see FIGS. 2 to 4), and a right side thereof is provided. The extension 44a is formed. A through hole 50 is formed in the diameter expansion portion 44c in the diameter direction. The cross section of the through hole 50 is a long hole in the axial direction. Further, a through hole 44d reaching the through hole 50 along the axis is formed from the right end surface of the extension portion 44a in the figure. The second gear 47 is rotatable around the extension portion 44a.

2 to 4 of the second gear 47 are formed with two bottomed recesses 49, 49 in the diametrical direction. The steel balls 48, 48 fit in here. A disk-shaped disc 51 having a through hole formed in the center thereof is movable in the axial direction in the enlarged diameter portion 44c of the intermediate shaft 44. The disk 51 has two notches 5 in the radial direction.
3, 53 are formed, and both ends of the pin 52 are fixed thereto. The pin 52 penetrates the through hole 50 and is attached. When the disk 51 moves axially of the intermediate shaft 44, the pin 52 moves axially in the through hole 50. As shown in FIGS. 3 and 5, when the pin 52 is located on the side of the steel ball 48, the pin 52 is located on the right side of the elongated through hole 50 in FIG. On the other hand, as shown in FIGS. 4 and 6, when the pin 52 gets over the steel balls 48, 48, the pin 52 moves to the left in FIG. 4 and the pin 52 moves to the left of the through hole 50 having a long hole shape. As shown in FIGS. 3 and 5, when the second gear 47 rotates with the pin 52 positioned on the side of the steel ball 48, the pin 52 also rotates. As a result, the intermediate shaft 44 also rotates. On the other hand, FIG.
As shown in FIG. 6, when the steel ball 48 pushes the pin 52 to the left, the pin 52 does not rotate. Ie the second
Even if the gear 47 rotates, the pin 52 and the intermediate shaft 44 do not rotate. In this way, steel balls 48
A clutch A is mainly constituted by the pin 52 to make the second gear 47 and the intermediate shaft 44 in a torque transmittable state or in an idle state.

As shown in FIG. 1, a torque adjusting knob 82 is rotatable around a shaft 83 below the substantially central portion of the upper housing 73. An eccentric cam 84 is fixed to the upper end of the shaft 83. A slider 85 is arranged near the eccentric cam 84, and the slider 85 is slidable in the left-right direction in FIG. As best shown in FIGS. 2-4, the slider 85
The vertical plate 85a of the circular plate 54 having a through hole at the center
Is fixed. A spring 54c is circumferentially rotatable on the disc 54 by a bearing 54b.
The spring 4 is provided between the spring receiver 54c and the disc-shaped disc 51.
3 is mounted in a compressed state. Inside the spring 43, a shorter and stronger spring 42 is attached.

FIG. 1 shows a state in which the radius of the eccentric cam 84 to the right in the figure is minimum, and in this state, the spring receiver 54c.
Is located on the leftmost side, and the compression force of the spring 43 is weakest. Therefore, the steel ball 48 pushes the pin 52 to the left only by applying a weak torque between the second gear 47 and the intermediate shaft 44, and the torque cannot be transmitted from the second gear 47 to the intermediate shaft 44. That is, the clutch A idles. When the knob 82 is rotated to increase the radius of the eccentric cam 84 to the right in the drawing, the spring receiver 54c moves to the right and the pressing load of the spring 43 increases. In response to this, when the pin 52 is pushed out by the steel ball 48 and the torque cannot be transmitted, the torque value increases. When the knob 82 is further rotated and the spring receiver 54c is short and compresses the strong spring 42, the force for biasing the pin 52 to the right is further increased, and the pin 52 is constituted by the steel ball 48 and the pin 52. The torque at which the existing clutch A starts to idle rapidly increases.
When the eccentric cam 84 is adjusted to have the maximum radius in the right direction in the drawing, the spring receiver 54c is located on the rightmost side. In this case, the spring receiver 54c and the second gear 47
There is not enough space for the steel ball 48 to push the pin 52 to the left in between, and the pin 52 moves to the steel ball 4
You will not be able to get over 8. Ie pin 5
The clutch A, which is composed of 2 and the steel ball 48, is in the non-idle state.

As described above, the torque value at which the steel ball 48 and the pin 52 start idling can be adjusted by the knob 82, the eccentric cam 84, etc., and the state in which the disengagement of the clutch A is prohibited can be realized. ing. The push rod 81 is biased by the spring 80 and abuts against the side of the knob 82, so that the knob 82 does not rotate carelessly.

In this embodiment, a mechanism for turning off the motor 74 when the pin 52 is pushed leftward by the steel ball 48 is added. This will be explained next. Note that reference numeral 21 in FIG. 1 denotes a trigger operated by the operator to rotate the tool, and the operator continues to press this while tightening the screw. By the mechanism described above, (1) if the clutch A is disengaged even if the trigger 21 is continuously pressed, the motor 74
Is turned off, and (2) once the trigger 21 is turned off and then turned on again, energization of the motor 74 is started. The details are shown in FIGS.

2 to 4, reference numeral 10 is a micro switch, which energizes the motor 74 as long as the button 17 on the side is pushed. The button 17 is biased toward the side where it pops out. Reference numeral 11 in the drawing denotes a holder of the micro switch 10, which fixes the micro switch 10 to the housing 73, and guides a guide hole 15 for guiding the sensor pin 16 and a groove 2 for guiding the upper end 21a of the trigger 21.
0 is formed. Micro switch 10 has screw 12
It is fixed to the holder 11 with.

The microswitch 10 has a first elastic piece 13
Are fixed by the base portion 13a. The first elastic piece 13 has a substantially U shape, and the sensor pin 16 is attached to the intermediate piece 13b. The sensor pin 16 is inserted into the through hole 44d of the intermediate shaft 44. The sensor pin 16 is provided with a collar 65, and a compression spring 66 is inserted between the collar 65 and the piece 11 a of the holder 11. As a result, the sensor pin 16 is urged to come into contact with the pin 52. The first elastic piece 13 wraps around to form a piece 13c, and the piece 13c is positioned corresponding to the button 17.

The second elastic piece 1 is attached to the support pin 19 of the holder 11.
8 is swingably attached. The state of FIG. 2 shows a state where the trigger 21 is not operated. In this state, the upper end 21a of the trigger is at the left end position in the figure, the button 17 is protruding, and the tip 18e of the second elastic piece 18 is the first position. The tip 13d of the elastic piece 13 is pushed from the outside. FIG. 3 shows a case where the trigger 21 is operated.
1a pushes the second elastic piece 18, the second elastic piece 18 pushes the first elastic piece 13, and the first elastic piece 13 pushes the button 17. This starts energization of the motor 74.

FIG. 4 shows when the steel ball 48 pushes the pin 52 to the left, the sensor pin 16 moves to the left, and the intermediate piece 13b of the first elastic piece 13 is pulled to the left. The tip 13d of the first elastic piece 13 is moved to the second
It is separated from the tip 18e of the elastic piece 18. For this reason, the button 17 pops out and the power supply to the motor 74 is stopped. At this time, as will be understood from the fact that the upper end 21a of the trigger 21 is located on the right side in the drawing, the trigger 21
The energization of the motor 74 is stopped even when is operated. When the trigger 21 is returned after this state, the state of FIG. 2 is restored, and the operation of the trigger 21 enables re-energization. Thus, in this embodiment, even if the trigger 21 is operated, the clutch A is disengaged and the motor 74 is de-energized at the same time.

When the second gear 47 rotates at a high speed, the sensor pin 16 becomes difficult to move, and even if the clutch A is disengaged, the button 17 does not easily pop out. However, in this embodiment, since the speed reduction mechanism C sufficiently reduces the speed between the first gear 76 and the second gear 47, such inconvenience does not occur.

Next, returning to FIG. 1, the structure of the tip side of the intermediate shaft 44 will be described. The third gear 87 meshes with the gear teeth 44b of the intermediate shaft 44. Third gear 87
3 shafts 89, 89, 89 are fixed to the end surface on the left side in the figure of FIG.
90, 90 are attached. Planet gears 90, 90,
Reference numeral 90 meshes with gear teeth 91a of the main shaft 91. Spindle 9
1 is rotatably supported by bearings 86 and 92. The third gear 87 is rotatable around a main shaft 91 by a bearing 88. The planetary gear 90, the internal gear 103, and the sun gear 91a constitute a speed increasing mechanism B, and the main shaft 91 rotates faster than the intermediate shaft 44.

A slide cover 96 is slidable on the main shaft 91. This slide cover 96 has a spring 9
It is urged to the right in the figure by 7. Reference numeral 98 is a retaining ring for the spring 97. A steel ball 95 is housed inside the slide cover 96 so as not to fall out. FIG. 1 shows a state in which the driver bit 99 is attached to the main shaft 91, and the steel ball 95 fits into the groove 99a of the driver bit 99 so that the driver bit 99 does not fall off. When exchanging the bit, the slide cover 96 is moved to the left in the drawing. Then, the steel ball 95 can move in the outer peripheral direction, and the driver bit 99 can be removed. When tightening nuts and sockets, socket bits are used instead of the driver bits 99. That is, the bit can be replaced according to the type of screws.

In this embodiment, the speed reduction mechanism C keeps the rotation speed of the second gear 47 low, and the sensor member (sensor pin 16) follows the displacement of the pin 52 well. Further, the speed increasing mechanism B sufficiently increases the number of rotations of the main shaft 91, so that screw tightening can be speeded up. Therefore, the small screws can be fastened one after another, and the work can be speeded up. When the rotation speed of the main shaft 91 is increased, it is unavoidable that the tightening torque is reduced accordingly. However, in the tool of the present embodiment, not only the rotation speed of the main shaft 91 is high, but the clutch A rotates freely. Since the speed increasing mechanism B rotates together with the main shaft 91 when starting the, the substantial moment of inertia of the main shaft 91 or the bit 99 increases. This is because when the main shaft 91 is directly connected to the clutch A, there is no moment of inertia of the speed increasing mechanism B.

When the screws are screwed into the screw holes in which the female screw is formed in advance, a large torque acts between the main shaft and the motor shaft at the same time as the neck of the screws comes into contact with the screw holes, and the clutch is released. Be disconnected. And at about the same time, the screw stops rotating. At this time, the rotational energy of the main shaft is transmitted to the screw, and the screw is strongly tightened. In this phenomenon, large rotational energy is transferred to the screw when the substantial moment of inertia of the bit is large. In the tool of the present embodiment, since the inertial energy of the speed increasing mechanism B is also transmitted to the screw, the final screw tightening force can be obtained despite the low torque due to the increased spindle speed. It is possible to keep high.

Before reaching this embodiment, the present inventor devised various structures around the sensor pin 16 so that even if the clutch A is rotated at the same speed as the main shaft rotation speed of the present embodiment, the sensor pin 16 will not be removed. I tried to move it smoothly, but it worked. This example solves all of these problems at once.

[Brief description of drawings]

FIG. 1 is an overall sectional view of an embodiment.

[Fig. 2] Enlarged view of main parts (before driving)

FIG. 3 is an enlarged view of a main part (during driving)

[Fig. 4] Enlarged view of main parts (when excessive torque is applied)

FIG. 5 is a diagram corresponding to FIG.

FIG. 6 is a diagram corresponding to FIG. 4;

FIG. 7 is a VII-VII diagram of FIG.

[Explanation of symbols]

 A: Clutch 42, 43: Spring 44: Intermediate shaft 47: Second gear 48: Steel ball 49: Recess 51: Disc 52: Pin 75: Motor drive shaft 82: Torque adjustment knob 84: Eccentric cam 91: Main shaft B: Increase Speed mechanism C: Reduction mechanism

Claims (1)

[Claims] 1. A clutch is added between a main shaft on which a bit is mounted and an output shaft of a drive motor for rotating the main shaft when the excessive torque is applied, and the drive is performed when the clutch starts to rotate. In a rotary tool incorporating a mechanism for stopping the power supply to a drive motor, a reduction mechanism is added between the output shaft of the drive motor and the clutch, and a speed increasing mechanism is added between the clutch and the main shaft. A rotary tool with a torque clutch interlocking motor-off mechanism.