JPS61293735A - Automatic screw tightening machine - Google Patents

Abstract

PURPOSE:To enable the smooth exchange of clutch mechanism parts by providing in an internal cylinder a clutch mechanism connected to a driver bitt in such a way that said mechanism can be detached from a differential planetary mechanism. CONSTITUTION:A driver body 12 has a housing 18 screwed to a cylinder 17 and the bottom thereof. This internal cylinder 18 is connected to a fixing tool 16 by a bolt 38 and the fixing tool 16 is so fixed to a driver mount 8 as to be freely detachable. Also, the driver body 12 has a motor 19 as a turning drive source and fixed to the housing 18, and the drive shaft 19a of said motor 19 is connected with the input disc 21 of a differential planetary mechanism 20. Furthermore, a connecting shaft 28 has a hexagonal coupling hole at the lower end and the projected hexagonal part of a clutch shaft 29 as part of a clutch mechanism in the internal cylinder 17 is so coupled to said hexagonal hole as to be detachable, thereby turning the connecting shaft 28 and the clutch shaft 29 monolithically.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an automatic screw tightening machine in which a deceleration mechanism that decelerates the rotation of a motor and a clutch mechanism that engages and disengages the rotation of the motor are completely shielded and separably connected. .

Conventional technology Conventionally, in order to eliminate the influence of inertia of the driver bit when screw tightening is completed, there is a device that tightens the screw at high speed and low torque until the screw is seated on the workpiece, and then tightens the screw at low speed and high torque after seating. Common.

An example of this type of device is a power screw tightening machine with an automatic transmission described in Japanese Utility Model Publication No. 51-14556. This screw tightening machine has a motor 19 fixed to a housing 18, as shown in FIGS. 8 and 9, and its drive shaft constitutes a drive gear 42 of a planetary gear mechanism 41. The gear 42 meshes with a ring gear 43 via a planetary gear 44. The rotation of the planetary gear 44 is configured to be transmitted to the output shaft 45 via a carrier pin 49. Further, the ring gear 43 is connected to the output shaft 45 via a slip clutch 46, and when a torque of more than a predetermined torque is applied to the ring gear 43 due to the load torque of the output shaft 45, the output shaft 45 and the ring gear 43 After the planetary gear 44 is disengaged from the ring gear 43, the planetary gear 44 is configured to rotate along the ring gear 43 or independently.

In this screw tightening machine, until the screw is seated on the workpiece, the rotation speed of the motor 19 is transmitted to the driver bit (not shown) at the tip of the output shaft 45 via the planetary gear 44, and the screw is driven at high speed and low torque. It can be tightened with. After that, when the screw comes into contact with the workpiece and its tightening torque approaches a predetermined torque, the slip clutch 46 disengages and the output shaft 45
The ring gear 43, which was rotating together with the planetary gear 44, is rotated by the planetary gear 44 and receives a rotational force in the opposite direction, but it is stopped at that position by the stop plate 47 and the one-way stop collar 48, so the planetary gear 44 is rotated. Rotates along ring gear 43. Therefore, the rotation speed of the motor 19 is reduced according to the gear ratio of the planetary gear 44 and the ring gear 43, so that the screw is tightened at low speed and high torque.

Problems to be Solved by the Invention The above-mentioned screw tightening machine uses gears 42, 43, and 44 as a reduction mechanism to reduce the rotation speed of the motor 19, and in order to avoid wear of the gears as much as possible, the clutch is The bottom of a housing 18 containing many parts such as a mechanism is shielded, and the housing 18 is filled with lubricating oil so that the area around the gear mechanism is filled with lubricating oil. Therefore, when replacing the clutch part inside the housing 18,
Not only does it have to handle the lubricating oil inside the housing 18, but it also requires disassembling the screw tightening machine and removing parts connected to the clutch mechanism, such as the motor and gear mechanism, which takes time and reduces work efficiency. This results in disadvantages such as poor quality, troublesome maintenance, and soiling of the device.

Means for Solving the Problems The present invention is aimed at eliminating the above-mentioned drawbacks, and the driver body is comprised of a housing fixed to the driver stand and an inner cylinder. A rotary drive source is fixed to the housing, and a connecting shaft is connected to the drive shaft via a differential planetary mechanism that decelerates the rotation of the rotary drive source. This connecting shaft is rotatably held by the inner cylindrical portion, and furthermore, this connecting shaft is sealed by a sealing mechanism. Lubricating oil is filled between the inner cylindrical portion and the housing,
Further, a clutch mechanism located within the inner cylinder portion is rotatably held on the driver mounting base.

A clutch mechanism is removably fitted to one end of the connecting shaft, and a driver bit is connected to the clutch mechanism so as to rotate together with the clutch mechanism.

Function: In the automatic screw tightening machine described above, the differential planetary mechanism that decelerates the rotation of the rotary drive source is disposed between the housing and the inner cylindrical portion 17, is shielded by the inner cylindrical portion 17, and is connected to the driver bit. Since the clutch mechanism is arranged in the inner cylindrical part 11 so as to be separable from the differential planetary mechanism, the clutch mechanism and the differential planetary mechanism can be separated by simply removing the inner cylindrical part 17, which is integrated with the housing, from the driver mounting base. The mechanism can be completely separated from the clutch mechanism, and when replacing the clutch mechanism, there is no need to remove the rotary drive source and differential planetary mechanism from the housing, and there is no need to remove the lubricating oil that is filled around the differential planetary mechanism. , only the clutch mechanism can be removed.

EXAMPLE Hereinafter, an example will be described with reference to the drawings. In FIGS. 1 to 3, reference numeral 1 denotes an automatic screw tightening machine, which has a support 3 implanted in a base 2. As shown in FIG. A fixing plate 4 is fixed to the support column 3, and an upper bracket 5 and a lower bracket 6 are fixed to the fixing plate 4 above and below. A cylinder 7 is fixed to the upper bracket 5, and a driver mounting base 8 is fixed to its rod (not shown). A chuck stand 10 elastically biased by a first spring 9 is arranged on the driver mount 8 at a predetermined interval. They are configured to move together along the same line to a predetermined position. Further, a driver main body 12 is provided on the upper part of the driver mounting base 8.
is held, and this driver body 12 is connected to the connecting mechanism 1.
The screwdriver bit 14 is configured to rotate through the screwdriver bit 3.

On the other hand, a chuck unit 15 is fixed to the chuck base 10, and the driver bit 14 is inserted into the chuck unit 15 and screws a screw (not shown) held by the chuck claw 15a into a predetermined position. is configured to do so.

The driver main body 12 has an inner cylindrical portion 17 and a housing 18 that is screwed into the bottom portion of the inner cylindrical portion 17.
is connected to a fixture 16, which will be described later, by a bolt 38, and this fixture 16 is detachably fixed to the driver mounting base 8. Further, the driver main body 12 has a motor 19 as a rotational drive source fixed to the housing 18, and an input disk 21 of a differential planetary mechanism 20 is connected to the drive shaft 19a. This input disk 21 has an annular portion 21a on its outer periphery, and this annular portion 21a transmits power formed by circumferential grooves 23a of a plurality of planetary cones 23 held with their axes inclined by a cone holder 22. It is configured to frictionally engage the surface. Moreover, this planetary cone 23
has a flat surface 23b on its surface, a cam disk 24 is frictionally engaged with this flat surface 23b, and this planetary cone 23
is held between the input disk 21 and the input disk 21. Further, a speed change ring 25 is positioned around the planetary cone 23 so as to be in contact with its conical surface 23C, and this speed change ring 25 is held by a plurality of piano wires 26, which will be described later. This piano wire 26 is bent in accordance with the torque applied to the speed change ring 25, and the speed change ring 25 is bent with the conical surface 23C.
The frictional engagement position of the gear change ring 25 changes.
The reduction ratio determined by the 2119 engagement position of the cam disc 24 changes continuously, and the rotational speed of the cam disc 24 decreases. Further, the cam disc 24 is configured to rotate at zero when the frictional engagement position of the speed change ring 25 reaches the position shown in FIG. 4 (a position satisfying a:b=c:d). .

A pressure regulating mechanism 27 is connected to the cam disk 24, and the cam disk 24 is configured to press the planetary cone 23. The pressure regulating mechanism 27 has a connecting shaft 28, which passes through the cam disk 24 and is rotatably held via a bearing fixed to the upper part of the inner cylindrical portion 17. . The connecting shaft 2
An oil seal mechanism is arranged around the connecting shaft 28.
The differential planetary mechanism and the pressure regulating mechanism 27 are connected to the inner cylinder part 1 by sealing the shaft.
7. Further, oil is filled between the housing 18 and the inner cylindrical portion 17 to prevent wear of the differential planetary mechanism 20.

Further, the connecting shaft 28 has a hexagonal engagement hole 28a at its lower end.
The hexagonal protrusion 29a of the clutch shaft 29, which is part of the clutch mechanism disposed in the inner cylindrical portion 17, is removably fitted into the hexagonal engagement hole 28a, thereby connecting the connecting shaft 28 and the clutch shaft. 29 are configured to rotate together. A drive clutch section 30 is rotatably fitted into the lower end of the clutch shaft 29. This drive clutch section 30 and the clutch shaft 29 are connected by a second spring 31, and the connecting mechanism 13 and driver bit 14 are connected to each other by a second spring 31. The second spring 31 is configured to absorb inertia during rotation.

A driven clutch 81 is provided below the drive clutch section 30.
32 is rotatably arranged, the clutch shaft 29 is inserted into the driven clutch section 32, and a third spring 33 is arranged between it and the drive clutch section 30. Further, the driven clutch portion 32 has a hollow portion as shown in FIG. 6, and the locking pin 3 protrudes into the hollow portion.
4 is installed. This locking pin 34 has a hemispherical portion at its tip, and this locking pin 34 engages with a pin 35 implanted in the clutch shaft 29, so that the rotation of the clutch shaft 29 is constantly transmitted to the driven clutch portion 32. It is configured to Furthermore, the driven clutch section 32 is connected to the articulated mechanism 13, so that the rotation of the motor 19 is transmitted to the driver bit 14.

On the other hand, a torque adjustment sleeve 3 is provided on the outer periphery of the inner cylindrical portion 17.
6 is slidably disposed, and a plurality of piano wires 26, which are linear elastic bodies, are fixed between the bottom of the inner cylindrical portion 17 and the speed change ring 25, as shown in FIG. has been done. The torque adjustment sleeve 36 has notched grooves 36a at equal intervals on its outer periphery, and the piano wire 26 is configured to pass through the notched grooves 38a. Also,
The torque adjustment sleeve 36 has a flange portion into which an adjustment bolt 37 rotatably held at the bottom of the inner cylindrical portion 17 is screwed. By changing the height position of the piano wire 36, the spring constant of the piano wire 26 changes, and the tightening is configured so that an elastic force corresponding to the torque is obtained.

In the automatic screw tightening machine described above, when the motor 19 rotates, the rotation is transmitted from the input disk 21 to the cam disk 24 via the planetary cone 23. When the driver main body 12 is lowered by the operation of the cylinder 7, the driver bit 14 is fitted into the screw in the chuck claw 15, and the screw comes into contact with the workpiece, and the lowering of the driver bit 14 is stopped. Roughly speaking, since the driver body 12 descends, the driven clutch 32 integrated with the driver bit 14 rises relatively, the driving clutch 30 and the driven clutch 32 are engaged, and the driver bit 14 drives this screw into a predetermined position. Screw into position. Along with this, the torque for tightening the screw increases, and when the load torque of the driver bit 14 increases and its rotational speed decreases, the speed change ring 25 receives the torque.

As the torque applied to the speed change ring 25 increases, the deflection of the piano wire 26 also increases as shown in FIG.
The movement of the speed change ring 25 stops at the friction engagement position where the torque applied to the speed change ring 25 and the elastic force of the piano wire 26 are balanced.

Roughly speaking, as the tightening torque increases, the speed change ring 25 will continue to slide, and the reduction ratio will become larger and larger, until the cam disc 24 will stop moving even though the input disc 21 is rotating. The rotation is stopped, the driver bit 14 is held at a predetermined torque of 1 to 1 torque, and the screw tightening is completed.

In addition, when parts of the clutch mechanism such as the driving clutch section 30 and the driven clutch section 32 of this automatic screw tightening machine are worn out and need to be replaced, the inner cylinder section 17 that is integrally fixed to the housing 18 can be moved with a screwdriver. When it is removed from the mounting base 8 and this inner cylinder part 17 is lifted upward, the connecting shaft 28 and the clutch shaft 29 are separated, and the differential planetary mechanism 20 and the clutch mechanism can be easily separated. Therefore, the motor 19 and the differential planetary mechanism 20 are completely removed from the housing 18.
It is possible to disassemble only the clutch mechanism and replace the necessary parts without removing it from the vehicle.

DETAILED DESCRIPTION OF THE INVENTION As described in detail, the present invention provides a differential planetary mechanism that reduces the rotation of the motor between the housing and the inner cylindrical portion;
The connecting shaft, which is rotatably held within the inner cylinder, and the clutch mechanism located within the inner cylinder are configured to removably fit together, so when replacing the clutch mechanism, you simply need to remove the driver body. All you need to do is remove it from the driver mounting base, and there is no need to remove the motor or differential planetary mechanism at all. Not only can you smoothly replace parts of the clutch mechanism, but you can also fill the area around the deceleration mechanism that decelerates the rotation of the motor. Since there is no need to scoop out the lubricating oil, the device is not contaminated with lubricating oil or the like, and there are advantages such as being able to provide a device that is extremely easy to maintain.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of the main part of the present invention, FIG. 2 is an overall explanatory diagram of the present invention, FIG. 3 is a partially cutaway sectional view of the driver main body according to the present invention, and FIG. 4 is a difference according to the present invention. FIG. 5 is an enlarged sectional view of the main part showing the operating state of the moving planetary mechanism, FIG. 5 is a perspective view of the main part of the torque adjustment ring according to the present invention, and FIG.
FIG. 7 is a sectional view of the main part showing the operating state of the present invention, FIG. 8 is a sectional view of the main part of the conventional example, and FIG. 9 is an enlarged perspective view of the main part seen from line A. FIG. 1 automatic screw tightening machine, 2 base, 3 support, 4 fixing plate, 5 upper bracket, 6 lower bracket, 7 cylinder, 8 driver mounting base, 9 first spring, 10 chuck base, 11 guide shaft, 12 driver main body, 13 connecting mechanism, 14 driver bit, 15 chuck unit, 15a chuck claw, 16 fixture, 17 inner cylinder part,
18 housing, 19 motor, 1
9a drive shaft, 20 differential planetary mechanism, 21 human power disk, 21a annular portion, 22 cone holder, 23 planetary cone, 23a circumferential groove, 24
Cam disc, 25 speed change ring, 26 piano wire, 21 pressure regulator groove, 28 connecting shaft,
28a hexagonal engagement hole, 29 clutch shaft,
29a hexagonal protrusion, 30 drive clutch portion, 31
Second spring, 32 Driven clutch portion, 33 Third
Spring, 34 Locking pin, 35 Pin, 36
Torque adjustment sleeve, 36a notch groove, 37 adjustment bolt, 38 bolt, 41 planetary gear mechanism,
42 Drive gear 43 Ring gear, 44
Planetary gear, 45 Output shaft, 46
Slip clutch, 47 Stopper plate, 48
One-way brim, 49 carrier pin,

Claims (1)

[Claims] The driver body 12 is composed of an inner cylindrical part 17 and a housing 18, which are detachably held on a driver mounting base 8, and a rotational drive source is fixed to the housing 18, and connected to the drive shaft via a differential planetary mechanism 20. connected to the shaft 28, this connecting shaft 2
8 is rotatably held by the inner cylindrical portion 17, and the connecting shaft 28 is sealed by a sealing mechanism, and the inner cylindrical portion 17
While lubricating oil is filled between the housing 18 and the clutch mechanism, the clutch mechanism is rotatably held on the driver mounting base so as to be located within the inner cylinder portion 17, and one end of the connecting shaft 28 is detached from the clutch mechanism. An automatic screw tightening machine characterized in that a driver bit 14 is connected to the clutch mechanism so that the driver bit 14 can be fitted together and rotated integrally with the clutch mechanism.