JPS63200975A - Clamping torque regulating mechanism of power tool - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] 【Technical field】

The present invention relates to a tightening torque adjustment mechanism for electric tools, particularly electric screwdrivers.

[Background Art 1] In order to enable a tightening torque of 114n in a power tool such as an electric screwdriver, as shown in Fig. 7, the torque adjustment If is used as a torque limiter.
f structure is being incorporated. This torhufu R
To briefly explain the adjustment mechanism, an M star mechanism is arranged in the power transmission path from the motor 4 to the output shaft 48, and the ring gear 747 in this ix* structure is freely rotatable, and the end face of the ring gear 47 is A protrusion 50 is provided on the clutch, and a ball 51 is provided which comes into contact with the end face of the ring gear 47 on which the protrusion 50 is formed by the urging force of the clutch spring 53, and the clutch is screwed into the gear case 8. A shaft 58 is disposed between the handle 10 and the ring gear 47, and by moving the ring gear 47 back and forth as the clutch handle 10 rotates, the protrusion 50 on the ring gear 47 and the ball 51 are connected. This is done so that the engagement force changes. While the load torque is small, the rotation of the ring gear 47 is prevented by the engagement with the balls 51, so power is transmitted from the motor 4 to the output shaft 48! ! However, when the load torque applied to the ring gear 47 becomes larger than the engagement force between the balls 51 and the ring gear 47, the ring gear 47 starts to idle, and the rotation of the motor 4 is transferred to the output shaft 48. It won't be communicated. clutch handle 1
0, the engagement force between the ring gear 47 and the ball 51 changes, so the ring gear 47
starts idling.The load torque changes. Therefore, it is possible to perform tightening torque of 1lI9. However, in this case, the clutch handle 10 is screwed into the gear case 8, and the clutch handle 10 itself moves back and forth when adjusting the tightening torque.
The ease of fabrication and appearance is poor, and since the threaded part between the clutch handle 10 and the gear case 8 is exposed, there is a risk of malfunction due to contamination with dust, etc. As shown in Fig. 8. The clutch handle 10 is rotatably disposed at the tip of the main body 1, and is screwed into the clutch handle 10 at the opening between the clutch handle 10 and the shaft 58, and is slidable only in the axial direction. Some models are equipped with an adjustment member 52, but the problem with the conventional example described above has been solved, but the spring pressure of the clutch spring 53 is adjusted by the ring gear 47, shaft 58, and V131 adjustment member 52.
In order to engage the clutch handle 10 via the clutch handle 10, in other words, to engage the main body 1 that rotatably holds the clutch handle 10, there is a gap between the ring gear 47 and the ball 51 incorporated in the gear case 8. It is difficult to achieve dimensional accuracy in the axial direction, and as a result, there is a problem in that the torque adjustment setting value varies greatly depending on the type. [Object of the invention] The present invention has been made in view of the above points, and its purpose is to provide a product with good appearance and ease of development, and
It is an object of the present invention to provide a tightening torque adjuster for a power tool that has high assembly accuracy and less variation in torque adjustment setting values. A freely disposed clutch handle and an llI movable in the axial direction on the outer circumferential surface of the gear case installed inside the main body.
The adjustment member includes a torque adjustment latch portion disposed within the gear case, a clutch spring provided between the adjustment member and the clutch portion, and an adjustment member disposed between the gear case and the adjustment member. A first engaging portion is provided between the adjusting member and the clutch handle, and a first engaging portion is provided that allows the adjusting member to be moved in the axial direction by rotation of the clutch handle. It is characterized by having two engaging parts, and the adjustment member is $
Due to the presence of the second engaging portion, the clutch handle is rotated to cause axial movement, but the spring force of the clutch spring is received by the first engaging portion between the clutch spring and the gear case. The present invention will be described in detail below based on illustrated embodiments. First, to explain the overall structure, this power tool is an electric drill driver that has a dry bar 9a shown in FIG. 5(a) and a drill pin 9b shown in FIG. It consists of a main body 1 having a bit mounting part at its tip, and a grip 2 rotatably connected to the rear end of the main body 1, and the grip 2 also serves as a storage part for a battery pack 20. A clutch handle 10 for adjusting the tightening torque is provided at the tip, and the rear i
By rotating the grip 2 relative to the main body 1, which has a switch handle 11 on the side surface of the main body 1, the grip 2 is continuously connected to the main body 1 in a straight line, and the grip 2 shown in FIG. 2 with the folded state compared to 1
It is designed to be able to take on different states. Inside the main body 1 of this electric drill driver, there is a first
As shown in the figure, a motor 4, a two-stage planetary mechanism for decelerating the output of the motor 4, a tightening torque adjustment R mechanism for use as an electric screwdriver, and a chuck are provided. Both of the above-mentioned i-star mechanisms are arranged in the large diameter part on the rear side of the gear case 8, and the chuck is arranged in the small diameter part on the front side of the gear case 8. To explain these in order, the sun gear 41 provided on the output shaft of the motor 4 and the rIBy installed on the inner surface of the gear case 8.
A plurality of planetary gears 42 supported by a carrier 44 are engaged with the second ring gear 43? A plurality of 1! l
Star gear 46 is engaged. Planetary gear 4 here
6 is supported by a bearing 15 in the gear case 8, and is also supported by an output shaft 48 having a bit insertion hole 49 on its tip end surface. Tightening torque llll adjustment W1 structure is 3 in the second stage above! ! It utilizes a freely rotatable ring gear 747 in a star mechanism, and between the protrusion 50 formed on the axial end face of this ring gear 47 and the large diameter part and small diameter part of the gear case 8. A ball 51 is disposed in a through hole 16 provided to axially pass through the stepped portion of the gear case 8 and engages with the protrusion 50. an adjusting member 52, a clutch spring 53 having one end in elastic contact with the adjusting member 52 and the other end elastically contacting the ball 51 via a thrust plate 54, and a clutch rotatably attached to the tip of the main body 1. The adjusting member 52 has a female thread 56 formed on its inner circumferential surface that engages with a male thread 80 formed on the outer circumferential surface of the small diameter portion of the gear case 8, as shown in FIG. The outer peripheral surface is provided with a protrusion 55 that slidably engages with the axial longitudinal groove 18 formed on the inner surface of the clutch handle 10. On the other hand, it is designed to spiral forward and backward in the axial direction. The chuck has a hole formed in the curved surface of the output shaft 48 having a rectangular bit insertion hole 49, a ball 60 disposed in this hole, and a ball 60 facing inward on the outer peripheral surface of the output shaft 48. It is configured with a C-shaped leaf spring 61 attached thereto for urging. The drill bit 9b and the driver bit 9a are both configured to have an annular groove 90 on the circumferential surface of the base end of a rectangular cross section, and when inserted into the bit insertion hole 49, the ball 60 is inserted into the plate. It is held by the chuck by being elastically locked in the groove 90 under the bias of the spring 61. The pins 9a and 9b can be easily attached and removed from the chuck by inserting and removing them. Next, the operation of the torque adjustment mechanism that functions when used as an electric screwdriver will be explained. FIG. 1 shows a state in which the tightening torque is minimized, and the output of the motor 4 rises due to the ball 51 being locked by the biasing force of the first stage ylL star groove mechanism clutch spring 53, which prevents rotation. 2 with ring gear 47
The speed is reduced by the planetary mechanism in the second stage and transmitted to the output shaft 48 and the bit attached thereto. When the load torque applied to the ring gear 47 becomes higher than the engagement force between the ball 51 and the ring gear 47 given by the clutch spring 53, the ring gear 47 pushes out the ball 51 against the clutch spring 53. Start idling. Projection 50
The tightening torque is limited because the torque adjusting clutch section 5, which is made up of a ring gear 47 and balls 51, slips. By rotating the clutch handle 10, the adjusting member 52 is moved to the right in FIG. 1 and the clutch spring 53 is compressed.
Since the engagement force with the ring gear 47 increases, the load torque at which the ring gear 47 starts idling increases. In other words, the tightening torque increases. As shown in FIG. 2, when the clutch handle 10 is rotated until the clutch spring 53 is compressed all at once, the ring gear 4
7 is fixed and the tightening torque adjustment mechanism becomes inoperative. This means that it can be used as an electric drill. Incidentally, the thrust force applied from the clutch spring 53 to the ring gear 47 is applied to a pair of pins 59 and 59 that are attached to the gear case 8 through the gear case 8, as shown in FIGS. 1 and 4.
received by. In other words, not only the adjustment member 52 that compresses the clutch spring 53 by moving in the axial direction as the clutch handle 10 is ground, but also the ring gear 47 side are directly supported by the gear case 8. In particular, since the pin 59 inserted and fixed into the gear case 8 receives thrust force,
It is easy to receive the ring gear 47 with high precision so as not to hinder the rotation of the ring gear 47. In the above embodiment, gear case 8 and l! The first engagement portion with the adjustment member 52 has a screw structure, and I! ! Although the second engaging portion between the adjusting member 52 and the clutch handle 10 is configured to consist of the longitudinal groove 18 and the protrusion 55,
The first engaging portion between the gear case 8 and the 11!9 member 52, which moves in the axial direction as the clutch handle 10 is operated, is configured to receive the repulsive force of the clutch spring 53. For example, a slide groove and a protrusion that slidably engages with the slide groove may be provided between the gear case 8 and the adjusting member 52, and the axial direction of the adjusting member 52 with respect to the gear case 8 may be Click locking parts are formed at several positions within the movement range, and a taper cam is also provided on the clutch handle 10, so that the taper cam can be activated by rotating the clutch handle 10! The R adjusting member 52 may be moved in the axial direction. [Effects of the Invention] As described above, in the present invention, the clutch handle is rotatably disposed at the tip of the main body, and the adjustment member is moved in the axial direction by this rotation. In addition, although the adjustment member moves in the axial direction in conjunction with the rotation of the clutch handle, the spring force of the clutch spring is limited to the first part between the clutch spring and the gear case. Since it is received by the engaging part, the dimensions between the adjusting member and the torque adjusting clutch part can be assembled with high precision based on the gear case, and the torque is 114 g! There is little variation in setting values.

[Brief explanation of the drawing]

Figures 1 and 2 are longitudinal sectional views of one embodiment of the present invention, Figures 3 and 4 are cross sectional views of the same, and Figures 5 (a) and (b) are side views of a driver bit and a drill bit. , $6 Figure is a side view of the same as above, Figure 7 is a longitudinal sectional view of the conventional example, and Figure 8 is a longitudinal sectional view of another conventional example, where 1 is the main body, 5 is the clutch part, and 10 is the clutch handle. , 48 is an output shaft, 52 is an adjustment member, and 53 is a clutch handle. Agent Patent Attorney Ishi 1) Ai Figure 7 Figure 5 (a) (b) Figure 6

Claims (3)

[Claims] (1) A clutch handle rotatably disposed at the tip of the cylindrical body, an adjustment member movable in the ring direction on the outer circumferential surface of the gear case installed inside the body, and the gear case. A torque adjusting clutch section disposed inside the gear case, a clutch spring provided between the adjusting member and the clutch section, and a mechanism for axial movement and arbitrary positioning of the adjusting member between the gear case and the adjusting member. A first engaging portion is provided between the adjusting member and the clutch handle, and a second engaging portion is provided between the adjusting member and the clutch handle to move the adjusting member in the axial direction by rotation of the clutch handle. A tightening torque adjustment mechanism for a power tool, characterized in that: (2) The first engaging part has a threaded structure of a male thread and a female thread, and the second engaging part is provided in a vertical groove provided in the clutch handle and in the adjustment member, and is slidably engaged with the vertical groove. A tightening torque adjustment mechanism for a power tool according to claim 1, characterized in that the mechanism comprises a mating protrusion. (3) The tightening torque adjustment mechanism for a power tool according to claim 1, wherein the torque adjustment clutch portion receives a clutch spring load by a pin passing through the gear case.