JP2681247B2 - Clutch device in electric screwdriver - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clutch device for transmitting rotation from a drive device to a spindle provided with a driver bit in an electric screwdriver. 2. Description of the Related Art Conventionally, in an electric screwdriver of this type, a clutch device for transmitting rotation from a drive device to a main shaft having a driver bit and for interrupting the rotation transmission is mainly used. A dog clutch means is adopted, a main shaft provided with a driver bit is movably arranged in the axial direction, a movable clutch part is provided on the main shaft, and the movable clutch part is engaged with and disengaged from a main gear rotated from a drive device. A fixed clutch portion is provided, and the movable clutch portion is engaged with and disengaged from the fixed clutch portion by moving the main shaft in the axial direction. However, in the clutch device having the above structure, since the clutch device has a simple meshing clutch structure, the meshing (engagement / disengagement) between the movable clutch part and the fixed clutch part is performed. ) Is lacking in smoothness, and the axial length including the main shaft and the dog clutch device inevitably becomes long, that is, the axial dimension of the portion to which the driver bid is attached as the whole electric screwdriver becomes long, There is a problem that the workability in using the electric screwdriver is impaired. Therefore, in order to solve the above-mentioned conventional drawbacks, the present invention makes it possible to smoothly engage and disengage the movable clutch portion and the fixed clutch portion, and to shorten the axial length including the main shaft and the clutch mechanism. Therefore, it is intended to improve the workability of the electric screwdriver. In order to achieve the above-mentioned object, the present invention is mounted on a housing and has an end portion.
To a stopper which can come into contact with the site to tightening, the main gears to be rotated from the drive, provided with a driver bit and the
A main shaft movably supported together with the driver bit in an axial direction; and a mesh clutch mechanism that is operated by the axial movement of the main shaft to transmit rotation from the main gear to the main shaft and cut off the rotation transmission. In the electric screwdriver provided with, the clutch mechanism includes a fixed clutch portion provided on the main gear side and an axial direction on the main shaft side.
Always consist of a movable clutch portion which is urged in a direction away from the fixed clutch part by movably provided Rutotomoni same spindle axial movement and cooperating to and spring of the movable clutch part into a tubular shape As it forms
Assemble by inserting the spindle end into the tubular shape,
The engagement of the movable clutch portion with respect to the fixed clutch portion is allowed by allowing rotation transmission from the movable clutch portion to the main shaft and relative movement of the main shaft and the movable clutch portion in a predetermined range in the axial direction and the rotational direction at the mounting portion. Form the engaging means to control the disengagement, and screw it onto the driver bit to tighten it.
When pressed against the part that should be
And the movable clutch part retracts together.
Forming the amount of movement in the axial direction relative to the main axis
In this state, mesh with the fixed clutch to transmit rotation to the main shaft.
Allow the screw to tighten and place it in the area where it should be tightened.
To the specified depth, and the stopper end is
When it comes into contact with the part to be mounted, it moves with the fixed clutch part.
The mesh with the clutch part is released, and the movable clutch part and the main shaft
Spring bias when the relative torque between them disappears
Movement of the movable clutch part formed by force between the main shaft
The gist is that the meshed state is moved by an amount to bring the meshed state into non-contact . The movable clutch portion is pushed toward the fixed clutch portion side against the elastic force of the spring by pushing the main shaft in the axial direction and engaging means of the fitting portion of the main shaft and the movable clutch portion. When the movable clutch portion and the fixed clutch portion are engaged with each other, the rotation from the drive device is transmitted to the main shaft, and the stopper mounted on the main body is brought into contact with the member to be screwed, the main shaft and the movable clutch The portion is pushed in the direction opposite to the axial pushing by the clutch tooth height in the clutch means, the engagement between the movable clutch portion and the fixed clutch portion is disengaged, and the rotation is interrupted. The movable clutch part is completely disengaged from the fixed clutch part via the engaging means. An embodiment of the present invention will be described in detail below with reference to the drawings. First, the first embodiment shown in FIGS. 1 to 7 will be described. Reference numeral 1 denotes an electric screw driver as a whole, and its housing 1a is meshed with a gear 2 of a drive device (not shown). A main gear 3 is rotatably supported via a support shaft 4, and a main shaft 5 having a driver bit 6 at its tip in a cylindrical portion of the housing 1a moves axially on the same axis as the support shaft 4. And rotatably supported. The rear end of the main shaft 5 is opposed to the main gear 3 at a predetermined interval. A pair of meshing clutch means 7 is interposed between the main gear 3 and the rear end of the main shaft 5, and this clutch means 7 is the same as a fixed clutch part 8 provided on the main gear 3 side. A ring cap-shaped movable clutch section 9 is engaged with the fixed clutch section 8 so as to be meshable and is loosely fitted on the outer periphery of the main shaft 5. The rear end portion of the main shaft 5 is fitted (i.e., loosely fitted) to the inner circumference of the cylindrical portion of the movable clutch portion 9, and this fitting portion, that is, the outer circumference of the rear end portion of the main shaft 5. Is formed with three inclined grooves 10 to 10 which are displaced in the axial direction by a predetermined length at equal intervals, and the end portion of which is released at the inner circumference of the cylindrical portion of the movable clutch portion 9 facing the inclined grooves. Groove 11-
11 are also formed in three places. Then, the engaging balls 12 to 1 extend over the both grooves 10 to 10 and 11 to 11.
2 is fitted. Thus, the movable clutch portion 9 moves in the axial direction of the main shaft 5, the oblique grooves 10 to 10 and the engaging groove 1.
The engagement balls 12 to 12 in the shafts 1 to 11 are engaged with and disengaged from the fixed clutch portion 8 by axial movement. In addition, between the main gear 3 and the movable clutch portion 9, the first and second springs 13 and 13a for constantly urging the movable clutch portion 9 in the direction to disengage the movable clutch portion 9 from the fixed clutch portion 8. Is mounted. A cylindrical stopper sleeve 14 for fitting the driver bit 6 so that the distal end thereof projects is provided at the tip of the cylindrical portion of the housing 1a by means of screw means. The protrusion degree of the knob 14 with respect to the tip of the driver bit 6 can be adjusted according to the screwing depth to be tightened with respect to the tubular portion of the housing 1a. This embodiment is constructed as described above, and after adjusting the projecting degree of the stopper sleeve 14 in accordance with the screw-in depth of the screw Y to be tightened, the tip of the driver bit 6 is tightened. The head of the screw Y to be fitted is matched and the screw Y is brought into contact with the portion W to be tightened. In this state, as shown in FIG. 5, the engaging balls 12 to 12 are located in the inclined grooves 10 to 10 and the engaging grooves 11 to 11 apart from the main gear 3 of the inclined grooves 10 to 10, that is, Since the movable clutch 9 is disengaged from the fixed clutch 8 at the lower side in the figure, when the drive device is rotated, only the main gear 3 is rotated to rotate the main shaft 5 and the driver bit 6. The rotation to is not transmitted. (See FIG. 7A) Then, the main body 1 of the electric screwdriver.
Is pressed (downward in the figure), the main shaft 5 along with the driver bit 6 is axially moved toward the main gear 3 side, and the movable clutch portion 9 resists the elasticity of the spring 13 and the main gear 3 side. And the engagement with the fixed clutch portion 8 is started, and the rotation from the drive device is performed via the main gear 3 to the main shaft 5
Is transmitted to the driver bit 6 and the driver bit 6 starts rotating. (7th
(See FIG. B) Further, when the driver bit 6 rotates as described above, and the tightening of the screw Y is started by the rotation of the driver bit 6, the movable clutch portion 9 is moved along with the rotation transmission operation. While being completely meshed with the fixed clutch portion 8, the engaging balls 12 to 12 are formed in the inclined grooves 10 to 10 and the engaging grooves 11 to 11, respectively.
The main shaft 5 is moved to a tip end portion of the main groove 3 of 0 to 10 which is close to the main gear 3, and as a result, the main shaft 5 is pushed out by an axial displacement amount a of the inclined grooves 10 to 10 and its end face and the movable clutch portion 9
A gap a'corresponding to the deviation amount a is generated between the and.
(See FIG. 4 and FIG. 7C) As described above, the tightening of the screw Y proceeds, and the electric screw is accompanied with this tightening operation.
When the whole body 1 of the driver is advanced and the tip of the stopper sleeve 14 of the body 1 comes into contact with the portion W to be tightened, the advance of the body 1 with respect to the screw Y to be tightened is stopped. The main shaft 5 and the movable clutch portion 9 are temporarily pushed by the clutch tooth height b of the fixed clutch 8 in the direction opposite to the pushing direction, and the screw bit Y is tightened by the driver bit 6 by that much b. Done,
After that, the engagement between the movable clutch portion 9 and the fixed clutch portion 8 is disengaged. (See FIGS. 7D and 7E) Then, at the moment when the engagement between the movable clutch portion 9 and the fixed clutch portion 8 is disengaged, the engagement balls 12 to 12 between the main shaft 5 and the movable clutch portion 9 to 12 is moved along the inclined grooves 10 to 10 by the elasticity of the spring 13, and the main gear 3
Since the displacement amount a is moved (escaped) in the direction away from the movable clutch unit 9, the displacement amount a with respect to the main shaft 5 is increased.
Is moved by a gap a'corresponding to the gap a ', and the gap a'is formed between the fixed clutch portion. Here, the engagement between the movable clutch portion 9 and the fixed clutch portion 8 is completely disengaged, and rotation transmission from the main gear 3 to the main shaft 5 is completely cut off. (See FIGS. 7E and 7F) Therefore, the disengagement operation of the fixed clutch portion 8 and the movable clutch portion 9 can be smoothly and reliably performed without producing mechanical noise or the like. Next, the second embodiment will be described with reference to FIGS. 8 to 11. This embodiment has a configuration in which the second spring 13a in the first embodiment described above is eliminated. Since the rest of the configuration is the same as that of the first embodiment, the same reference numerals are given in the figure and the description thereof is omitted. Therefore, this embodiment enjoys the same functions and effects as those of the first embodiment. Further, referring to FIGS.
This embodiment is a mode in which the movable clutch portion and the like in the first embodiment described above are modified, and the configuration thereof will be described below. As with the first embodiment described above, Shows an electric screwdriver as a whole, and a main gear 17 meshed with a gear 16 of a drive unit (not shown) is rotatably supported by a support shaft 18 in a housing 15a thereof. Also housing 15
A main shaft 19 having a driver bit 20 having a hexagonal hole, for example, is supported at the tip in the cylindrical portion of a so as to be axially movable and rotatable on the same axis as the support shaft 18. The rear end of the main shaft 19 is opposed to the main gear 17 with a predetermined space. A pair of meshing clutch means 21 is interposed between the main gear 17 and the rear end of the main shaft 19, and the clutch means 21 is a fixed clutch portion mounted on the main gear 17 side. 22 and a movable clutch portion 23 that is movably opposed to the fixed clutch portion 22 and is mounted on the rear end portion of the main shaft 19. Then, the mounting state of the movable clutch portion 23 with respect to the rear end portion of the main shaft 19 will be described. A flange portion 24 is integrally formed at the rear end portion of the main shaft 19, and a circular recess 25 is formed on the end surface of the flange portion 24. Then, on the inner peripheral surface of the recess 25, three engaging grooves 26 to 26 of a predetermined length are formed at equal intervals in the circumferential direction from the end surface to the bottom surface, and the bottom surface of each engaging groove 26 is As shown in FIG. 14, a substantially V-shaped sloping surface 26a having the deepest central portion, that is, a sloping surface 26a having an axial displacement amount is formed. The movable clutch portion 23 includes a boss portion 23a and a flange portion 23.
b, the boss portion 23a is integrally formed in the circular recess 25 of the flange portion 24 of the main shaft 19, and the engagement groove is formed on the outer periphery of the boss portion 23a. The engaging groove 26 is provided at a portion opposed to 26-26.
An engaging groove 27 having a bottom surface which forms an approximately V-shaped inclined surface 27a which releases the end portion symmetrical to
~ 27 are also formed in three places. Then, the engaging balls 28 to 28 extend over the grooves 26 to 26, 27 to 27.
28 is fitted. Then, the movable clutch unit 23
Is an engaging groove 26-26, 2 having slanted surfaces 26a, 27a having a displacement of the main shaft 19 in the axial direction and a displacement in the axial direction.
The engagement balls 28 to 28 in 7 to 27 are axially moved to engage and disengage the fixed clutch portion 22. Incidentally, the main gear 17 and the movable clutch portion 2
3, a spring 29 for constantly urging the movable clutch portion 23 in a direction to disengage the movable clutch portion 23 from the fixed clutch portion 22.
Is armed. Further, a cylindrical stopper sleeve 30 for fitting the driver bit 6 so that the distal end thereof projects is provided by a screw means at the tip of the cylindrical portion of the housing 15a. The degree of protrusion of the knob 30 with respect to the tip of the driver bit 6 can be adjusted according to the screw-in depth to be tightened with respect to the tubular portion of the housing 15a. The third embodiment is constructed as described above, and its operation is different from that of the first embodiment in that the engagement shaft in the relationship between the main shaft 19 and the movable clutch portion 23 is different. The only difference is that the movement control of the levers 28 to 28 is performed on the inclined surfaces 26a and 27a having the axial deviation amounts of the engagement grooves 26 to 26 and 27 to 27, respectively. All are the same as those in the first embodiment.
Therefore, the same operation and effect as those of the first embodiment can be expected. Although the inclined grooves 10 to 10 are formed on the main shaft 5 side in the first embodiment described above, they may be formed on the movable clutch 9 side, and further, in each of the above-described embodiments, the engagement balls 12 to 10 are formed. Instead of 12, 28 to 28, engaging pins may be provided so as to project, and the engaging pins may be combined with the inclined groove and the engaging groove. Furthermore, the clutch device of both embodiments can be easily applied to a pneumatic screwdriver. As described above, according to the present invention, the movable clutch is
The latch part is formed in a tubular shape, and the main shaft is
By assembling by inserting the end portion, rotation transmission from the movable clutch portion to the main shaft and relative movement in the predetermined range of the axial direction and the rotational direction between the main shaft and the movable clutch portion are allowed at the assembled portion. by forming the engaging means for controlling the engagement and disengagement movement of the movable clutch part relative to the fixed clutch part, it is possible to achieve smooth engagement and disengagement operation of the fixed clutch part movable clutch part in the assembling site, Main shaft and clutch mechanism , engagement of this clutch mechanism
The axial length including the means for controlling disengagement and disengagement can be shortened. This is the tightening area where the screw should be tightened.
Of the electric screwdriver as a whole including the stopper means that abuts against the shaft, the axial dimension of the portion to which the driver bid is attached is shortened as much as possible to improve the workability such as the ease of use of the electric screwdriver. be able to.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a first embodiment of the present invention, FIG. 1 is a front view including a partially cutaway view, FIG. 2 is an exploded perspective view of essential parts, and FIG. 3 shows an operating state. FIG. 4 is an enlarged cross-sectional view of essential parts. FIG. 4 is a front view showing a meshed state of the clutch means. FIG. 5 is a front view showing a disengaged state of the clutch means. (A) ~ (F) is an explanatory view showing an operating state [Fig. 8] A front view showing a second embodiment of the present invention including a partial break [Fig. 9] An exploded perspective view of a main part [Fig. 10] FIG. 11 is an enlarged cross-sectional view of an essential part showing a state. FIG. 11 is a cross-sectional view taken along the line BB of FIG. 10. FIG. 12 is a front view including a partially broken view showing a third embodiment of the present invention. 14 is a cross-sectional view taken along the line cc of FIG. 14. Explanatory view showing both groove portions in an expanded manner [Explanation of reference numerals] 1,15 ... Main body 3, 17 ... Main gear 5, 19 ... Main shaft 6, 20 ... Driver bit 7 21: clutch means 8, 22 ... fixing clutch unit 9, 23 ... movable clutch portion 10 ... inclined grooves 12, 28 ... Kakarigobo - le 26 ... engaging groove

Claims (1)

(57) [Claims] The part that is installed in the housing and the end of which should be tightened
A stopper capable of abutting against the position, a main gear rotated from the drive device, and a driver bit.
Both are provided with a main shaft movably supported in the axial direction, and a mesh clutch mechanism that is operated by the axial movement of the main shaft and that transmits rotation to the main shaft from the main gear and cuts off the rotation transmission. and in the electric screwdriver, the clutch mechanism is moved in cooperation axial Rutotomoni the spindle <br/> provided movably in the axial direction on the fixed clutch part and the main shaft side is provided on the main gears side by and composed of a movable clutch part is always biased in a direction away from the fixed clutch part by the spring, the movable clutch
The part is formed into a circular shape, and the spindle end is
The assembly is assembled by inserting the parts, and the assembly is allowed to transmit rotation from the movable clutch part to the main shaft and relative movement of the main shaft and the movable clutch part in a predetermined range in the axial direction and the rotational direction. form an engagement means for controlling the engagement and disengagement movement of the movable clutch part relative to the fixed clutch part, the de
Place the screw on the driver bit and push it to the area to be tightened.
When attached, the spindle will retract with respect to the stopper.
The movable clutch part retracts and
Fixed clutch with a relative amount of axial movement formed
Tighten the screw by engaging with the section to allow rotation transmission to the spindle.
A predetermined depth to the part where the screw is to be tightened
The part that is tightened up to the end of the stopper
Contact the fixed clutch part and the movable clutch part.
And the relative torque between the movable clutch and the main shaft
When there is no torque, the movable clutch is driven by the spring force.
The part by the amount of movement formed between the main shaft and the main shaft.
A clutch device for an electric screwdriver, characterized in that the engagement state of the two is non-contact .