JP3661387B2 - Tightening torque adjustment device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tightening torque adjusting device used for a tightening tool such as an electric screwdriver, that is, a tightening torque adjusting device that makes the set value variable in a torque clutch that cuts off power transmission when the tightening torque reaches a set value. It is about.
[0002]
[Prior art]
Various types of tools with a torque clutch that cuts off power transmission when the tightening torque reaches a set value have been provided. Conventionally, these torque clutches are connected together by mutual engagement. When the load torque becomes larger than the set value, the transmission of power is cut off by repeating idling while one clutch member rides on the protrusion on the other clutch member. In general, the setting value is made variable by adjusting the spring force of the clutch spring that biases the clutch member toward the other clutch member. Yes.
[0003]
FIG. 7 shows an example of a conventional tightening torque adjusting device. A plurality of planetary gears 22 supported by a carrier 24 mesh with a sun gear 21 provided on the rotating shaft 20 of the motor and a ring gear 23 fixed to the inner surface of the gear case 8, and are formed integrally with the carrier 24. A plurality of planetary gears 26 are engaged with the sun gear 25 and the ring gear 27. The carrier 28 supporting the planetary gear 26 is integrally provided with a sun gear 29 of a third stage planetary mechanism, and this sun gear 29 and a ring gear 31 arranged in a freely rotatable manner in the gear case 8. Planetary gears 30 are engaged with each other. The carrier 32 supporting the planetary gear 30 is connected to the output shaft 9 via a lock plate 60 in the lock mechanism. The ring gear 27 is slidable in the axial direction. In the state shown in the upper part of FIG. 7, the ring gear 27 meshes with the carrier 28 and rotates integrally with the carrier 28. In the state shown in the lower part of FIG. The case 8 meshes with the case 8 so that its rotation is locked, and shifting is performed by switching between the two states. The locking mechanism performs automatic locking of the output shaft 9 during manual tightening work, but the description thereof is omitted here.
[0004]
The tightening torque adjusting device uses a ring gear 31 that is freely rotatable in the third stage planetary mechanism. A ridge 310 formed on an end surface of the ring gear 31 in the axial direction, a gear case, and the like. 8 is arranged in a through hole provided so as to penetrate the stepped portion in the axial direction, and is arranged on the outer peripheral surface of the gear case 8 having a small diameter and the ball 33 engaged with the protrusion 310. And a clutch spring 37 that elastically contacts one end of the adjusting member 34 and elastically contacts the ball 33 via the clutch plate 36 at the other end.
[0005]
The adjustment member 34 includes an internal thread that engages with an external thread formed on the outer peripheral surface of the small diameter portion of the gear case 8 on the inner peripheral surface, and is screwed back and forth in the axial direction with respect to the gear case 8. The annular clutch plate 36 positioned between the clutch spring 37 and the ball 33 is non-rotatable and axially movable with respect to the gear case 8.
[0006]
Now, when the adjusting member 34 is in the position shown in the upper side of FIG. 7, the output of the motor is generated by the ball 33 being locked by the first and second stage planetary mechanisms and the bias by the clutch spring 37. It is decelerated by the third stage planetary mechanism having the ring gear 31 that is prevented from rotating and transmitted to the output shaft 9. When the load torque applied to the ring gear 31 is higher than the engagement force between the ball 33 and the protrusion 310 of the ring gear 31 provided by the clutch spring 37, the ring gear 31 resists the clutch spring 37. The ball 33 is pushed out to start idling. Since the torque clutch composed of the ring gear 31 and the ball 33 slips, the tightening torque is limited.
[0007]
When the adjustment member 34 is moved to the left in FIG. 7 to increase the compression amount of the clutch spring 37, the engagement force between the ball 33 and the ring gear 31 increases, so that the load torque at which the ring gear 31 starts idling. Becomes larger. That is, the tightening torque increases.
When the adjustment member 34 is further moved to the left side so that the pressing protrusion 341 provided on the adjustment member 34 is in contact with the clutch plate 36 as shown in the lower part of FIG. Since it becomes impossible to move backward by being pushed by the ridge 32, the starting torque of the torque clutch becomes infinite, which is suitable for use as an electric drill.
[0008]
[Problems to be solved by the invention]
By the way, even in the locked state in which the pressing protrusion 341 is brought into contact with the clutch plate 36 to prevent the movement of the clutch plate 36 as described above, if the load torque increases, the protrusion 310 of the ring gear 31 passes through the ball 33. The clutch plate 36 is pushed up, but the position where the ball 33 is in contact with the clutch plate 36 is closer to the outer periphery than the position where the pressing protrusion 341 of the adjustment member 34 is in contact with the clutch plate 36.
[0009]
For this reason, when the push-up of the clutch plate 36 by the ball 33 with a large load torque is repeated many times in the locked state in which the pressing projection 341 is brought into contact and the movement of the clutch plate 36 is prevented, the clutch plate 36 is deformed. And the pressing protrusion 341 of the adjustment member 34 may be crushed. In the case where the portion of the clutch plate 36 that contacts the pressing projection 341 is a projecting piece that protrudes to the inner peripheral side so that the clutch plate 36 can be unlocked by rotating the adjustment member 34 at a slight angle, the clutch plate 36 is still more of a projecting piece. Deformation tends to occur.
[0010]
The present invention has been made in view of these points, and an object of the present invention is to provide a tightening torque adjusting device in which malfunction due to deformation of a clutch plate or the like is unlikely to occur.
[0011]
[Means for Solving the Problems]
Accordingly, the present invention provides a torque clutch that cuts off the power transmission to the output shaft by pushing up the clutch plate against the clutch spring as the load torque increases, and one end abutting the clutch plate in the torque clutch. And an adjusting member for receiving the other end of the clutch spring, the spring force by which the clutch spring presses the clutch plate by the movement of the adjusting member is adjustable, and the clutch spring of the clutch plate is brought into contact with the clutch plate. In the tightening torque adjustment device in which the adjustment member that prevents the movement against the adjustment member is provided in the adjustment member, the adjustment member that is engaged with the male screw provided on the outer periphery of the output shaft holding part and moves in the axial direction by rotation thereof is the restricting portion abutting on the annular clutch plates disposed on the outer periphery of the output shaft holding section, member and the clutch plate to push the clutch plate with an increase in load torque Together provided on both sides the position of sandwiching the contact point and outer circumferential sides, a particular feature in a position where the restricting portion is located in the regulating portion and the inner peripheral side located on the outer peripheral side shifted in the circumferential direction Yu doing.
[0012]
In this case , the adjustment member may be formed in a double cylinder shape, and a restricting portion may be provided at each end of the inner cylinder and the outer cylinder between which the clutch spring is disposed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on an example of the illustrated embodiment. FIG. 4 shows a tightening tool equipped with a tightening torque adjusting device according to the present invention. A driver bit and a drill bit are selectively attached. In addition, a battery in a storage battery pack (not shown) that is detachably attached to the handle portion of the main body 1 is used as a power source, and the motor 2 that is fed through a switch unit 16 that is turned on when the trigger handle 15 is pulled is rotated. It is a battery-powered electric type as a power source. A gear case 8 and a tightening torque setting member configured as shown in FIG. 1 are housed between the motor 2 and the output shaft 9 provided with the chuck 90 in the main body 1. A clutch handle 3 is rotatably attached to the front end portion of the main body 1, and a protrusion that slidably engages with an axial longitudinal groove formed on the inner surface of the clutch handle 3. Since 34 is provided on the outer peripheral surface, the adjusting member 34 is screwed back and forth in the axial direction with respect to the gear case 8 as the clutch handle 3 rotates. Reference numeral 65 in FIG. 4 denotes a speed change handle. By moving the speed change handle 65 back and forth, the ring gear 27 moves back and forth.
[0014]
Since the configuration of each member arranged in the gear case 8 is the same as that shown in the conventional example, only the adjustment member 34 and the clutch plate 36 will be described here. The adjusting member 34 used here is a double cylinder on the clutch plate 36 side, and the adjusting member 34 for positioning the clutch spring 37 between the inner cylinder and the outer cylinder is a clutch plate in the inner cylinder. A plurality of pressing projections 341 are projected from the end surface on the 36 side, and at the same time, a plurality of pressing projections 342 are projected from the end surface on the clutch plate 36 side of the outer cylinder. It should be noted that the inner peripheral pressing protrusion 341 and the outer peripheral pressing protrusion 342 are provided at different positions in the circumferential direction as shown in FIG.
[0015]
On the other hand, as shown in FIG. 3, the clutch plate 36 is provided with a portion a that contacts the pressing projection 341 as a protruding piece that protrudes toward the inner peripheral side, and a portion B that contacts the pressing projection 342 protrudes toward the adjustment member 34 side. It becomes what was provided as a convex part. 3 indicates the position of the ball 33, and the clutch spring 37 is in contact with the clutch plate 36 inside the circle passing through the point where the ball 33 contacts, and the portion B where the pressing protrusion 342 contacts the ball It can be positioned in the vicinity of the point where 33 contacts.
[0016]
In order that the pressing protrusion 342 positioned on the outer peripheral side of the clutch spring 37 locks the clutch plate 36, the pressing protrusion 341 positioned on the inner peripheral side of the clutch spring 37 locks the clutch plate 36. In contrast, the deformation of the clutch plate 36 is less likely to occur, and not only the pressing protrusion 342 but also the pressing protrusion 341 is used in combination with the inner peripheral side and the outer peripheral side of the clutch spring 37 (ball Since the clutch plate 36 is locked at the inner periphery side and the outer periphery side of the circle passing through the contact point between the clutch plate 36 and the clutch plate 36, the clutch plate 36 is further less likely to be deformed. Further, since the number of contact portions of the adjustment member 34 with the clutch plate 36 is increased, the surface pressure applied to the individual pressing protrusions 341 and 342 is reduced, and therefore, the pressing protrusions 341 and 342 are not easily crushed.
[0017]
【The invention's effect】
As described above, in the present invention, the adjustment member that is screwed with the external screw provided on the outer periphery of the output shaft holding portion and moves in the axial direction by the rotation thereof is an annular clutch disposed on the outer periphery of the output shaft holding portion. Restricting portions that contact the plate are provided at both the inner and outer peripheral positions sandwiching the contact point between the clutch plate and the member that pushes up the clutch plate as load torque increases, and are also positioned on the outer peripheral side. And the restricting portion located on the inner peripheral side are shifted in the circumferential direction, the push-up force is increased by increasing the load torque when the restricting portion is in contact with the clutch plate and the clutch plate is locked. be added to the plate, which deform the clutch plate is less likely to occur, without impairing at all the function as the torque clutch, Ru can be reliably prevented deformation during locking clutch plate.
[0018]
In addition, providing the restricting portions on the inner peripheral side and the outer peripheral side means that the adjusting member is formed in a double cylinder shape, and the restricting portions are provided at the end portions of the inner cylinder and the outer cylinder between which the clutch spring is disposed. This can be realized simply.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an example of an embodiment of the present invention.
FIGS. 2A and 2B show the adjustment member of the same, wherein FIG. 2A is a rear view and FIG. 2B is a cross-sectional view.
FIG. 3 is a front view of the above clutch plate.
FIG. 4 is a sectional view of a tightening tool provided with the same as above.
FIG. 5 is a side view of the above gear block.
FIG. 6 is a front view of the gear block.
FIG. 7 is a cross-sectional view of a conventional example.
[Explanation of symbols]
33 Ball 34 Adjustment member 36 Clutch plate 37 Clutch spring 341 Press protrusion 342 Press protrusion

Claims (2)

A torque clutch that blocks power transmission to the output shaft by pushing up the clutch plate against the clutch spring as the load torque increases, and a clutch spring having one end abutting against the clutch plate in the torque clutch. An adjustment member for receiving the other end, and the spring force by which the clutch spring presses the clutch plate can be adjusted by the movement of the adjustment member, and the clutch plate abuts against the clutch spring by contacting the clutch plate. In the tightening torque adjusting device having the adjusting member provided on the adjusting member, the adjusting member that is screwed with the male screw provided on the outer periphery of the output shaft holding portion and moves in the axial direction by the rotation thereof is provided on the output shaft holding portion. the clutch plate and restricting portion abutting annular arranged on the outer circumference, across the contact point between the member and the clutch plate to push the clutch plate with an increase in load torque Together provided the positions on both sides of the peripheral side and the outer peripheral side, tightening torque adjusting apparatus, characterized in that in a position where the restricting portion is located in regulating portion and an inner peripheral side located on the outer peripheral side shifted in the circumferential direction. 2. The tightening according to claim 1, wherein the adjusting member is formed in a double cylinder shape, and is provided with a restricting portion at each end of the inner cylinder and the outer cylinder between which the clutch spring is disposed . Torque adjustment device.

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