KR100556041B1 - Electric driver - Google Patents

Abstract

The present invention is a simple structure in which the rotational force transmission means of the electric screwdriver, when loosening the screw to apply a greater rotational driving force than when the screw is tightened to the driver bit, less wear of parts, the transmission to transmit a constant rotational force As for the driver,

Rotation input member 106 rotated and driven by the drive motor, drive roller 108 engaged with the rotation input member to which rotation driving force is transmitted, and rotatable rotation output member 110 driven to the bit holder. And a driven ball 112 which is held by the rotational output shaft and is engaged with the driving roller 108 to transmit the rotational driving force to the rotational output shaft, and the driving roller 108 has a rotational drive input member in the rotational center axis line. Are displaced with respect to the rotation input member 106 at the time of forward rotation and reverse rotation, and are engaged at different points with respect to the driven ball 112, thereby driving rollers and dodges from the rotation input member 106. It is characterized in that the rotational driving force transmitted to the rotary output member 110 through the ball is different.

Rotary input member, drive roller, rotary output member, driven ball

Description

Electric driver {ELECTRIC DRIVER}

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a sectional view showing a main part of a rotational force transmitting means in a conventional electric driver.

Fig. 2 is a sectional view showing a main part of a rotational force transmission means of another type in the conventional electric driver.

Figure 3 is a longitudinal sectional view of the electric driver according to the present invention.

Fig. 4 is a cross-sectional view along the line A-A in Fig. 3, showing a state at the time of screw tightening.

Fig. 5 is a sectional view taken along the same line A-A, showing a state when the screw is loosened.

6 is a longitudinal sectional view of another embodiment of the electric driver according to the present invention.

FIG. 7 is a cross-sectional view taken along line B-B in FIG. 6.

※ Explanation of symbols for main parts of drawing

100: electric driver 102: bit holder

102-1: center hole 102-2, 102-3: locking ball

104: rotational transmission means 105: reducer

106: rotation input member 106-1: roller holding portion

106-2: first holding part 106-3: second holding part

106-4: Displacement unit 106-5: First side

108: drive roller 110: rotation output member

110-1: cylindrical portion 110-2: radial through hole

110-3: second side 110-4: through hole

112: driven ball 120: cylindrical housing portion

124: spring pressure adjusting means 124-1: cylindrical member

124-2: Taper surface 124-3: Ball mill pressing member

124-4: coil spring 124-5: end cylindrical member

124-6: spring pushing member 124-7: spring end fitting member

124-8: spring adjustment member 130: pilot pin

a, b: radial position F: spring force

α, β: angle

The present invention relates to an electric driver, in particular, when the rotation transmission means for transmitting the rotational driving force from the drive motor to the bit holder when the screw is loosened (when forward rotation) by the electric driver ( The present invention relates to an electric driver that enables the side to transmit a large rotation driving force to the bit holder.

The electric screwdriver needs to give a greater rotational driving force than when tightening the screw at the first time of loosening the screw. On the other hand, when tightening the screw too much rotational driving force may damage them by applying excessive force to the screw itself, the member to which the screw is fastened, and the electric driver itself.

For this reason, the electric screwdriver usually has a torque limiting means for limiting the rotational driving force transmitted to the driver bit to a predetermined value or less.

1 shows an example of such torque limiting means. In the torque limiting means 10, the cylindrical member 12 which is rotationally connected to the driver bit, the drive shaft 14 which receives and rotates the rotation driving force from the drive motor, and the radially opposite side of the drive shaft A pair of rollers 16 set at a position, a pair of balls 20 set in a radial through hole provided at a position opposite to the radial direction of the cylindrical member 12, and a predetermined spring force in the radial direction. It has a spring means (not shown) which pushes in (F). When screwing in, the drive shaft 14 rotates counterclockwise to engage the roller 16 with the ball 20 (in the positional relationship indicated by the solid line with respect to the roller), and when the screw is loosened, the drive shaft 14 ) Rotates clockwise to engage the roller 16 with the ball 20 (in the positional relationship indicated by a dashed line with respect to the copper roller), and rotational driving force is applied to the copper ball 20 and the cylindrical member 12. It is passed to driver bit through. When the rotational driving force from the drive shaft 14 to the cylindrical member 12 becomes equal to or more than the predetermined, the ball 20 is displaced radially outward against the spring force F inwardly applied thereto, thereby driving the drive shaft. The idling is interrupted the transmission of the rotational driving force (for example, patent document 1). In this torque limiting means, torque limiting can be implemented in this way, because the radial position (from the center of rotation axis of the drive shaft) that the roller engages with the ball, even when tightening the screw, is the same as that of the rotational driving force that can be transmitted. The maximum value is the same, and therefore, it is not possible to satisfy the requirement to give a greater driving force at the time of loosening the screw.

On the contrary, the rotary drive shaft 14 is shaped as shown in Fig. 2, and accordingly, when the drive shaft 14 is rotated clockwise for loosening the screw, the drive shaft 14 is rotated counterclockwise for screwing. As compared with the above, the engagement position of the corresponding rotary drive shaft with respect to the ball 20 is engaged at a radial position away from the central axis of rotation of the rotary drive shaft 14 as shown in the figure, so that the larger rotary driving force is applied to the corresponding ball 20. There is a form of one that can be delivered (for example, Patent Document 2).

In such a case, if the drill is used for a certain period of time, wear occurs in the engagement portion of the rotary drive shaft 14 with the ball 20, and their engagement position is displaced inward in the radial direction. Rotational driving force applied to (20) may decrease.

There is also a type in which only one-way clutch is used to transmit the required rotational driving force from the rotational drive shaft to the ball without idling, in which case the loosening screw is too tightly tightened. There is a concern that the driving motor may be damaged or an operator may be injured due to the driver being unable to restrain the driver.

[Patent Document 1] Special Publication 2-42631

[Patent Document 2] Actual Fairness 2-12053

An object of the present invention is to provide an electric driver having a rotational transmission means that solves the above problems.

That is, the present invention,

A bit holder for holding the driver bit

It is an electric driver having a rotation transmission means for transmitting the rotational driving force from the drive motor to the bit holder,

Rotation transfer means,

A rotation input member which receives the rotation driving force from the drive motor and is rotated and driven;

A roller which is engaged with the rotation input member and transmits rotational driving force around the rotation center axis line of the rotation input member from the rotation input member;

A rotation output member connected to the bit holder and being rotatable about the rotation center axis of the rotation input member;

It is held by the rotation output member, is engaged with the drive roller and the rotation driving force is transmitted from the driving roller, and has a driven ball for transmitting the rotation driving force to the rotation output member,

The drive roller is displaced with respect to the rotational input member when the rotational drive input member is rotated forwardly and about the rotational center axis, and in a different direction from the rotational centerline with respect to the driven ball. It provides an electric driver characterized in that the rotational driving force transmitted from the rotation input member to the rotation output member through the driving roller, the driven ball according to the position.

According to this electric driver, since the rotational driving force transmitted from the driving roller to the driven ball can be changed at the forward rotation and the reverse rotation, it is possible to generate an appropriate rotational driving force at the time of screwing and loosening. In addition, since the rotational driving force is transmitted by engaging the driving roller and the ball, the reduction of the rotational driving force due to the wear described above can be reduced.

Specifically, the rotation output member has a cylindrical portion concentrically around the rotation input member, and the driven ball is held by the cylindrical portion, and the driving roller is configured to rotate the rotation input member forward. And at the other time of reverse rotation, it can be engaged with the driven ball at another radial position about the center of rotation axis.

More specifically, the rotation input member includes a first holding part for holding the drive roller when the rotation input member rotates forward and engages the driven ball, and the rotation input member rotates in reverse to drive roller. It may be provided with a ball holding portion having a second holding portion for holding the drive roller when engaging the driven ball, and a displacement portion for allowing the drive roller to be displaced between the first holding portion and the second holding portion.

In another embodiment,                         

The rotation input member is perpendicular to the rotation center axis line, and has a first surface facing the rotation output member;

The rotation output member is a disk-shaped member having a second surface parallel to the first surface,

The rotating output member has a through hole extending from the second surface to the opposite side, and the driven ball is held in the through hole to partially protrude from the second surface toward the first surface.

Wherein the first surface holds the drive roller with its axis arranged along the radial direction from the center of rotation axis, and wherein the drive roller rotates in reverse rotation with the forward rotation of the rotation input member. The distance to the second surface may be engaged with the driven ball at another position.

More specifically, the rotation input member,

A first holding part for holding the drive roller when the drive roller is engaged with the driven ball when the rotation input member rotates forward;

A second holding part for holding the driving roller when the driving roller is engaged with the driven ball when the rotation input member is reversely rotated;

A ball holding portion having a displacement portion that allows the drive roller to displace between the first holding portion and the second holding portion,

The driving roller held in the first holding portion can be positioned closer to the second surface than the driving roller held in the second holding portion, so that the driving roller can be engaged with the driven ball.

More specifically, the driven ball is sized to protrude from the second surface and the opposite side of the rotational output member, and is driven by a predetermined spring force by a ball mill pressing member set adjacent to the opposite side. It can be pushed toward the roller.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of the electric driver concerning this invention is described based on attached drawing (FIGS. 3-7).

3 is a longitudinal cross-sectional view of the electric driver 100 according to the present invention, FIG. 4 is a AA cross-sectional view of FIG. 3 at the time of screwing, and FIG. 5 at the time of loosening the screw in FIG. It shows the state.

As shown, the electric driver 100 drives the bit holder 102 for fixedly holding a driver bit (not shown) (inserted from the right end as shown in FIG. 3) and driving (set at the left end as shown in FIG. 1). Rotational transmission means 104 for transmitting rotational driving force from a motor (not shown) to the bit holder 102 is provided.

The rotation transfer means 104 receives the rotation driving force from the drive motor through the reduction gear 105 and is engaged with the rotation input member 106 and the rotation input member 106 that are rotated to drive the rotation input member 106. Drive roller 108 to which the rotational driving force is transmitted around the rotational center axis of the rotation input member 106 and the bit holder 102, and at the same time, the rotation of the rotation input member 106 The rotational output member 110, which is rotatable about the central axis, is held by the rotational output member 110 and engaged with the driving roller 108 to transmit the transmission of the rotational driving force from the driving roller 108. Received, and has a driven ball 112 for transmitting the rotational driving force to the rotational output member 110.

The rotation output member 110 has a cylindrical portion 110-1 formed concentrically around the rotation input member 106, and the driven ball 112 is formed in the cylindrical portion 110-1 in the radial direction. The through hole 110-2 is held in a radially displaceable manner.

The rotation input member 106 has a groove-shaped roller holding portion 106-1 as shown in FIGS. 4 and 5, and the roller holding portion 106-1 has a corresponding rotation input member at the time of screwing. When the 106 rotates counterclockwise (with the motor side seen from the drill bit side of the electric driver), and the driving roller 108 engages the driven ball 112, the driving roller 108 is held. Holding the drive roller 108 when the first rotation part 106-2 and the same rotation input member 106 are reversely rotated and the drive roller 108 is engaged with the driven ball 112 at the time of loosening the screw. The second holding portion 106-3 and the displacement portion 106- that allows the driving roller 108 to be displaced between the first holding portion 106-2 and the second holding portion 106-3. Have 4) Specifically, the roller holding portion 106-1 is a displacement portion that is substantially perpendicular to the diameter at a position opposite to the diameter direction of the rotational input member 106 which is circumferentially centered on the rotation center axis line as a whole. And the first holding portion 106-2 provided to be curved to conform to the curved surface of the driving roller 108 at one end of the displacement portion 106-4, and the other end is equally radially outwardly curved at the other end thereof. The radial position (b) of the drive roller 108 (from the center of rotation axis) held by the second holding part 106-3 and having the second holding part 106-3 provided is the first holding. It is made larger than the radial position a (from said rotation center axis line) of the drive roller 108 held by the part 106-2. The driven ball 112 has a predetermined spring force (F) is applied toward the center of rotation axis as described below, and is transmitted from the rotation input member 106 through the drive roller 108 (the ball 112 and the drive When the radially outward component force of the force (in the direction along the line connecting the center of the roller 108) becomes equal to or greater than the corresponding spring force F, the driven ball 112 is displaced radially outward so that the transmission of the rotational driving force is Under the spring force, the driven ball 112 is held at a position shown in the drawing, and the tangential component of the force transmitted to the driven ball 112 is used as the rotational driving force of the rotation output member 110. It will work. Thus, as described above, the second holding portion 106-3 is held at the radial position b (disting from the rotational center axis line) than the first holding portion 106-2. Angle (beta) becomes larger than angle (alpha) in FIG. 4, and it becomes possible to give rotation output member 110 the rotational driving force with a larger screw loosening side.

In Fig. 3, reference numeral 120 denotes a cylindrical housing portion of the electric driver, and a spring pressure adjusting means for allowing a spring force of radially inward deflection to the driven ball 112 to be adjusted at the tip of the cylindrical housing portion. 124 is provided. The spring pressure adjusting means 124 is installed in the cylindrical member 124-1 screwed to the distal end of the cylindrical housing portion 120 and movable in the axial direction in the cylindrical member, and hangs on the driven ball 112. A ball spring pressing member 124-3 having a tapered surface 124-2 to be fitted and a coil spring 124-4 for applying a spring pressure to the left direction as seen in FIG. 3 to the ball mill pressing member 124-3. ) And the cylindrical member 124-1 are screwed to the tip cylindrical member 124-5 fixed coaxially with the cylindrical member at the right end of the cylindrical member 124-1, and displaced in the axial direction by screw rotation. It has a spring adjustment member 124-8 which gives an appropriate pushing force to the coil spring 124-4 through the pushing member 124-6 and the spring end fitting member 124-7. The driver bit (not shown) is inserted from the right side in the center hole 102-1 of the bit holder 102, and is fixed by the locking ball 102-2. When the bit holder 102 is inserted, The pilot pin 130 extending along the central axis of the electric driver is pushed to the left to act on the start switch of the drive motor. As described above, when the screw is fastened, the resistance to fastening becomes large, and the driven ball when the radial force of the radially outward force of the force transmitted from the rotation input member 106 to the driving roller 108 becomes equal to or greater than the spring force F. 112 is displaced radially outward, accompanied by the ball-pressing member 124-3 being displaced to the right (as seen in FIG. 3), and the inclined surface near the right end of the member is a ball 102-. 3) push inward in the radial direction, accordingly push the pilot pin 130 to the left to close the start switch of the drive motor, and stop the drive of the electric driver.

6 and 7 show another embodiment of the electric driver according to the present invention.

This electric driver has the same basic configuration, but the transmission mechanism of the rotational driving force between the rotation input member 106 and the rotation output member 110 is different from that of the above embodiment.

That is, in this embodiment, the rotation input member 106 has a first surface (that is, the right facing surface in FIG. 7) 106-5 facing the rotation output member 110, while the rotation output member ( 110 is a disk-shaped member having a second surface 110-3 that is parallel to the first surface 106-5. The rotation output member 110 has a through hole 110-4 extending in the rotation axis direction, and the driven ball 112 is displaceably held in the through hole 110-4. The first surface 106-5 holds the drive roller 108 with its axis along a radial direction about the center of rotation axis, and the drive roller 108 is connected to the rotary input member 106. Accompanying the rotation, the driven ball 112 is engaged in the circumferential direction.

Specifically, as shown in FIG. 7, the roller holding part which extends along the circumferential direction made into the said rotation axis, and faces the 2nd surface to the 1st surface 106-5 of the rotation input member 106 is opened. 106-1 is formed, and the driving roller 108 in the roller holding part 106-1 is set to be movable so that its axis becomes a direction orthogonal to the circumferential direction (that is, the radial direction). have. The end of the roller holding portion 106-1 (lower side in Fig. 7) is driven by the driving roller 108 to the driven ball 112 when the rotation input member 106 rotates counterclockwise at the time of loosening the screw. By engaging, it engages with the said lower end part, and the 2nd holding part 106-3 for turning the driven ball 112 counterclockwise is formed. In addition, the end (upper side in Fig. 7) opposite the roller holding part 106-1 is engaged by being driven to the driven ball 112 when the rotation input member 106 is rotated clockwise when tightening. The first holding portion 106-2 engaged with the end portion and continuously rotating the rotation output member 110 through the driven ball 112 is formed. In this embodiment, the ball mill pressing portion 124-3 is a disk shape adjacent to the rotation output member 110, and the spring in the axial direction so as to push the driven ball 112 to the drive roller 108. Force is applied to the corresponding rotation output member 110.

As shown, the bottom surface of the roller holding groove is inclined, shallow in the second holding portion 106-3, and deep in the first holding portion 106-2. For this reason, the driving roller 108 held in the second holding portion 106-3 is closer to the second surface 110-3 than the driving roller 108 held in the first holding portion 106-2. It is brought into a close position to engage with the driven ball 112, and thus, as in the case of the first embodiment, it is possible to give the rotation output member 110 a greater rotational driving force than that of the first holding member.

Claims (6)

A bit holder for holding the driver bit In the electric driver having a rotation transmission means for transmitting the rotational driving force from the drive motor to the bit holder, Rotation transfer means, A rotation input member which receives the rotation driving force from the drive motor and is rotated and driven; A driving roller which is engaged with the rotation input member and transmits rotational driving force around the rotation center axis line of the rotation input member from the rotation input member; A rotation output member connected to the bit holder and being rotatable about the rotation center axis of the rotation input member; It has a driven ball which is held by the rotation output member, is engaged with the drive roller, the rotation driving force is transmitted from the driving roller, and transmits the rotation driving force to the rotation output member, The drive roller is displaced with respect to the rotational input member when the rotational drive input member is rotated forward and reversely about the rotational center axis line, and is engaged at a different point with respect to the driven ball. And a rotation driving force around the center of rotation axis transmitted from the rotation input member to the rotation output member through the driving roller and the driven ball. The method of claim 1, The rotation output member has a cylindrical portion concentrically around the rotation input member, The driven ball is held by the cylindrical portion, And the driving roller is engaged with the driven ball at another radial position about the center of rotation axis when the rotation input member rotates forward and reverse. The method of claim 2, The rotation input member, A first holding part for holding the driving roller when the rotation input member is rotated forward and the driving roller is engaged with the driven ball; A second holding part for holding the driving roller when the rotation input member is rotated in reverse and the driving roller is engaged with the driven ball; And a ball holding portion having a displacement portion that allows the drive roller to displace between the first holding portion and the second holding portion. The method of claim 1, The rotation input member is perpendicular to the rotation center axis line, and has a first surface facing the rotation output member. The rotation output member is a disk-shaped member having a second surface parallel to the first surface, The rotating output member has a through hole extending from the second surface to the opposite side, and holds the driven ball in the through hole to partially protrude from the second surface toward the first surface. The first surface holds the drive roller such that its axis is arranged along the radial direction from the center of rotation axis, and the drive roller is rotated when the rotation input member rotates forward and backward. And the distance to the second surface is to be engaged with the driven ball at different positions. The method of claim 4, wherein The rotation input member, A first holding part for holding the driving roller when the rotation input member is rotated forward and the driving roller is engaged with the driven ball; A second holding part for holding the driving roller when the rotation input member is rotated in reverse and the driving roller is engaged with the driven ball; A ball holding portion having a displacement portion that allows the drive roller to displace between the first holding portion and the second holding portion, And the driving roller held in the first holding portion is closer to the second surface than the driving roller held in the second holding portion so as to be engaged with the driven ball. The method of claim 5, wherein The driven ball is sized to protrude from the second surface and the opposite side of the rotation output member, and pushed toward the driving roller with a predetermined spring force by a ball mill pressing member set adjacent to the opposite side. Electric driver, characterized in that to lose.

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