JPH0466654B2 - - Google Patents

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 are completely shielded and separably connected.

Conventional technology Conventionally, in order to eliminate the influence of the inertia of the driver bit when screw tightening is completed, devices generally tighten the screw at high speed and low torque until the screw is seated on the workpiece, and then tighten the screw at low speed and high torque after seating. It is true. 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.
The drive shaft constitutes a drive gear 42 of a planetary gear mechanism 41, and this drive 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 a predetermined torque or more 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 are connected to each other. is disengaged, and thereafter the planetary gear 44 is configured to rotate independently along the ring gear 43.

In this screw tightening machine, until the screw is seated on the workpiece, the rotation speed of the motor 19 is transmitted to a 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 the tightening torque approaches the predetermined torque,
With the slip clutch 46 disengaged, the ring gear 43, which had been rotating together with the output shaft 45, receives the rotation of the planetary gear 44 and receives a rotational force in the opposite direction, but at that position, the ring gear 43 is rotated by the rotation of the planetary gear 44 and receives a rotational force in the opposite direction. 48, the planetary gear 44 rotates along the 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 In the above screw tightening machine, gears 42, 43, 4 are used as a reduction mechanism to reduce the rotation speed of the motor 19.
4, in order to avoid wear as much as possible, the bottom of the housing 18, which houses many parts such as the clutch mechanism, is shielded, and lubricating oil is filled inside the housing 18 to lubricate the area around the gear mechanism. It is designed to be filled with oil. Therefore, when replacing the clutch part inside the housing 18,
Not only does it have to drain 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 is time consuming and inefficient. As a result, maintenance becomes troublesome and the equipment becomes dirty.

Means for Solving the Problems The present invention aims to eliminate the above-mentioned drawbacks.
The driver body is composed of a housing fixed to a driver stand and an inner cylinder part. 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 is provided within the inner cylinder portion and having a clutch shaft releasably fitted to one end of the connecting shaft. This clutch mechanism is comprised of a driving clutch portion provided on a clutch shaft, and a driven clutch portion which is disposed so as to be meshable with the driving clutch portion and is connected to rotate integrally with the driver bit.

Function In the automatic screw tightening machine described above, the differential planetary mechanism that decelerates the rotation of the rotary drive source is connected to the housing and the inner cylindrical portion 17.
The clutch mechanism connected to the driver bit is disposed within the inner cylinder part 17 so as to be separable from the differential planetary mechanism, so that it is integrated with the housing. The clutch mechanism and differential planetary mechanism can be completely separated by simply removing the worn-out inner cylinder part 17 from the driver mounting base, and the rotational drive source and differential planetary mechanism can be removed from the housing when replacing the clutch mechanism. In addition, only the clutch mechanism can be removed without draining the lubricating oil around the differential planetary mechanism.

Embodiments Hereinafter, embodiments 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 fixed plate 4 is fixed to this support column 3, and upper brackets 5 are attached to this fixed plate 4 above and below.
and the lower bracket 6 are fixed. 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 at a predetermined interval on the driver mounting stand 8,
The driver mounting base 8 is configured to move together with the driver base along the guide shaft 11 to a predetermined position. Further, a driver main body 12 is held at the upper part of the driver mounting base 8, and this driver main body 12 is configured to rotate a driver bit 14 via a connecting mechanism 13. 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 screwed into a predetermined position with a screw (not shown) held by a chuck pawl 15a. It is composed of

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 cylinder portion 17.
This inner cylindrical portion 17 is attached to a bolt 3 to a fixture 16 to be described later.
8, and this fixture 16 is removably fixed to the driver mounting base 8.
Further, the driver main body 12 is connected to the housing 1.
It has a motor 19 as a rotational drive source fixed to 8,
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
are the circumferential grooves 23a of a plurality of planetary cones 23 held by the cone holder 22 with their axes inclined;
It is configured to frictionally engage with the transmission surface formed by the transmission surface. Moreover, this planetary cone 23 has a flat surface 23b on the back surface, and a cam disk 24 is frictionally engaged with this flat surface 23b, and holds this planetary cone 23 between it and the input disk 21. . Also,
Around the planetary cone 23, there is a conical surface 23.
A speed change ring 25 is positioned so as to be in contact with c, and this speed change ring 25 is held by a plurality of piano wires 26, which will be described later. This piano wire 2
6 is bent in accordance with the torque applied to the speed change ring 25, and the frictional engagement position of the speed change ring 25 with the conical surface 23c changes, whereby the speed change ring 25
The speed reduction ratio determined by the frictional engagement position of the cam disk 24 changes continuously, and the rotational speed of the cam disk 24 decreases. Further, the friction engagement position of the speed change ring 25 is the position shown in FIG. 4 (a:b=c:
When the position that satisfies d) is reached, the cam disc 2
4 is configured to have zero rotation.

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 2
7 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. An oil seal mechanism is arranged around the connecting shaft 28, and an oil seal mechanism is arranged around the connecting shaft 28.
The differential planetary mechanism and the pressure regulating mechanism 27 are shielded by the inner cylindrical portion 17 by sealing the shaft. 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, and a hexagonal protrusion of a clutch shaft 29, which forms a part of the clutch mechanism disposed in the inner cylindrical portion 17, is located in the hexagonal engagement hole 28a. 29a is removably fitted, so that the connecting shaft 28 and the clutch shaft 29 rotate together. A drive clutch portion 30 is provided at the lower end of the clutch shaft 29, the extension of which is configured to fit into a hollow portion of the driven clutch shaft having a driven clutch portion 32. The drive clutch portion 30 and the clutch shaft 29 are connected by a second spring 31, and the second spring 31 absorbs the inertia that the connecting mechanism 13 and the driver bit 14 have when they rotate. . A driven clutch portion 32 is rotatably disposed below the driving clutch portion 30, and the clutch shaft 29 is inserted into the driven clutch portion 32. A spring 33 is arranged. Further, the driven clutch portion 32 has a hollow portion as shown in FIG. 6, and a locking pin 34 is attached so as to protrude into the hollow portion. This locking pin 34 has a hemispherical portion at its tip, and this locking pin 34 is connected to a pin 35 implanted in the clutch shaft 29.
The clutch shaft 29 is engaged with the clutch shaft 29 so that the rotation of the clutch shaft 29 is constantly transmitted to the driven clutch portion 32.
Further, the connecting mechanism 13 is connected to the driven clutch portion 32, and the rotation of the motor 19 is transmitted to the driver bit 14.

On the other hand, a torque adjustment sleeve 36 is slidably disposed on the outer periphery of the inner cylindrical portion 17, and there is a line between the bottom of the inner cylindrical portion 17 and the speed change ring 25 as shown in FIG. A plurality of piano wires 26, which are shaped like elastic bodies, are fixed. The torque adjustment sleeve 36 has notched grooves 36 at equal intervals on its outer circumference.
a, and the piano wire 26 is configured to pass through this notched groove 36a. 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 26, the spring constant of the piano wire 26 changes, so that an elastic force corresponding to the tightening torque can be obtained.

In the above automatic screw tightening machine, when the motor 19 rotates, the rotation is transmitted from the input disk 21 to the planetary cone 2.
3 to the cam disk 24. When the driver body 12 is lowered by the operation of the cylinder 7, the driver bit 14 is fitted into the screw in the chuck pawl 15, and the screw comes into contact with the workpiece, and the lowering of the driver bit 14 is stopped. Further, since the driver body 12 is lowered, the driven clutch 32, which is integrated with the driver bit 14, is relatively raised, the driving clutch 30 and the driven clutch 32 are engaged, and the driver bit 14 holds this screw in a predetermined position. screw into. Along with this, the tightening torque of the screw increases, the load torque of the driver bit 14 increases, and when the rotational speed thereof decreases, the speed change ring 25 receives the torque. When the torque applied to the speed change ring 25 increases, the piano wire 2
The deflection of the gear ring 6 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.

Furthermore, as the tightening torque increases, the speed change ring 25 continues to slide, and the reduction ratio increases, until the input disc 21
Although the cam disk 24 rotates, the rotation of the cam disk 24 stops, and the driver bit 14 stops while being held at a predetermined torque, completing the screw tightening.

In addition, the drive clutch part 3 of this automatic screw tightening machine
0. When parts of the clutch mechanism such as the driven clutch part 32 are worn out and need to be replaced, the inner cylinder part 17, which is integrally fixed to the housing 18, is removed from the driver mounting base 8, and the inner cylinder part 17 is replaced. When it 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, without removing the motor 19 and the differential planetary mechanism 20 from the housing 18, only the clutch mechanism can be disassembled and necessary parts can be replaced.

Effects of the Invention As explained above, the present invention provides a differential planetary mechanism that decelerates the rotation of the motor, which is disposed between the housing and the inner cylinder, and a connecting shaft and the inner cylinder that are rotatably held within the inner cylinder. Since it is configured to removably engage with the clutch mechanism located inside the unit, when replacing the clutch mechanism, it is only necessary to remove the driver body from the driver mounting base, and the motor and differential planetary mechanism Not only does it become unnecessary to remove parts such as the clutch mechanism, it is possible to smoothly replace parts of the clutch mechanism, but there is no need to drain the lubricating oil that is filled around the deceleration mechanism that decelerates the rotation of the motor. This has advantages such as being able to provide an extremely easy-to-maintain device without being contaminated by the like.

[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. 6 is an enlarged perspective view of the main part as seen from line A-A in FIG. 7 is a sectional view of a main part showing the operating state of the present invention, FIG. 8 is a sectional view of a main part of a conventional example, and FIG. 9 is a sectional view taken along the line BB in FIG. 1... Automatic screw tightening machine, 2... Base, 3... Support column, 4
...Fixing plate, 5...Upper bracket, 6...Lower bracket, 7...Cylinder, 8...Driver mounting base, 9
...first spring, 10...chuck stand, 11...guide shaft, 12...driver body, 13...coupling mechanism,
14...driver bit, 15...chuck unit, 15a...chuck claw, 16...fixing tool, 17...
Inner cylinder part, 18...Housing, 19...Motor, 19
a... Drive shaft, 20... Differential planetary mechanism, 21... Input disk, 21a... Annular part, 22... Cone holder, 23
... Planetary cone, 23a ... Circumferential groove, 24 ... Cam disk, 25 ... Speed change ring, 26 ... Piano wire, 27
...Pressure adjustment mechanism, 28...Connection shaft, 28a...Hexagonal engagement hole, 29...Clutch shaft, 29a...Hexagonal protrusion, 30
... Drive clutch part, 31... Second spring, 32... Driven clutch part, 33... Third spring, 34... Locking pin,
35...Pin, 36...Torque adjustment sleeve, 36a
...notch groove, 37...adjustment bolt, 38...bolt, 4
DESCRIPTION OF SYMBOLS 1... Planetary gear mechanism, 42... Drive gear, 43... Ring gear, 44... Planetary gear, 45... Output shaft, 46... Slip clutch, 47... Stopper plate, 48... One-way stopper, 49... Carrier pin.

Claims (1)

[Claims] 1. The inner cylindrical part 17 and the housing 18 that hold the driver body 12 in a detachable manner on the driver mounting base 8
A rotary drive source is fixed to the housing 18, and the drive shaft thereof is connected to a connecting shaft 28 via a differential planetary mechanism 20, and this connecting shaft 28 is rotatable by a bearing in the inner cylindrical portion 17. At the same time, the connecting shaft 28 is sealed by a sealing mechanism, and lubricating oil is filled between the inner cylinder part 17 and the housing 18. One end of the shaft 29 is removably fitted, and the other end is fitted into a driven clutch shaft having a driven clutch portion 32, which is comprised of a driving clutch portion 30 and a driven clutch portion 32 provided on the clutch shaft 29. Attach the clutch mechanism to the driver mounting base 8
An automatic screw tightening machine characterized in that a screwdriver bit 14 is rotatably held in a clutch mechanism, and a driver bit 14 is connected to the clutch mechanism so as to rotate integrally therewith.