JP2002028874A - Pneumatic screw fastener - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic screw fastener usable in the building environment with an inferior condition of a compressed air source, improving the durability of a planetary gear section and an oil pulse section, and having a small-sized and lightweight oil pulse mechanism. SOLUTION: An air motor 6, the planetary gear section 11, and the oil pulse section 12 are linearly arranged, with their rotation axes matched. The exhaust air from the exhaust hole 9 of the air motor 6 is fed via a first exhaust passage formed by a scooped space 23 provided around the planetary gear section 11 and a second exhaust passage formed around the oil pulse section 12, thus cooling the planetary gear section 11 and the oil pulse section 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic screwdriver having an oil pulse mechanism.

[0002]

2. Description of the Related Art A pneumatic screw tightening machine employing an oil pulse mechanism having a low impact sound is shown in FIG. 7 as an oil pulse type torque wrench used for tightening and loosening bolts and nuts in an automobile factory or the like. The structure is known. The pneumatic screw tightening machine shown in FIG. 7 is provided with an air supply port 4 connected to a compressed air source such as an air compressor (not shown) for supplying compressed air through an air hose or the like, and is provided in communication with the air supply port 4 to provide compression. A pressure accumulating chamber 5 for accumulating air, an air motor 6, an air supply valve 7 provided between the air motor 6 and the pressure accumulating chamber 5 for controlling communication between the air motor 6 and the pressure accumulating chamber 5, and a tip of a not-shown hexagon socket or the like. It has an anvil 19 to which a tool is attached, and an oil pulse unit 12 for transmitting rotation of the air motor 6 to the tip tool via the anvil 19. Since the oil pulse type torque wrench shown in FIG. 7 is an operation in a factory, a large output large fixed type air compressor is generally used as a compressed air source, which hardly causes a decrease in output due to a pressure drop inside the torque wrench. Driven.

[0003] In recent years, as the fastening method in the construction field has shifted from nailing to screwing, the demand for screw tightening machines has increased, and in particular, oil that has a small impact sound for screwing work in densely populated areas or remodeling. There is a strong need for a pulsed pneumatic impact driver. However, since the compressed air source used by general carpenters engaged in construction is a small-output, usually 1-1.5 hp portable air compressor, the pressure inside the driver is particularly high when screw tightening is performed continuously. The drop is large, and the output (torque) is insufficient in the structure of the conventional oil pulse type torque wrench used in the factory. It is conceivable to increase the size of the air motor for this purpose,
Then, the driver itself becomes large, and the air consumption increases accordingly. As a result, the pressure drop further increases, which is not preferable.

[0004]

In order to solve the above-mentioned drawbacks of the conventional pneumatic screwdriver, the required output (torque) is obtained by reducing the rotation of the air motor between the air motor and the oil pulse section. A pneumatic screwdriver equipped with a speed reduction mechanism, which is provided with a speed reduction mechanism composed of a planetary gear and the like and maintains the size of an air motor and an oil pulse unit, can be considered. However, it has been found that such a pneumatic screwdriver with a reduction mechanism also has the following new problems. In general, an impact time of about one second is sufficient to tighten bolts and nuts, whereas a screw for architectural purposes requires several seconds of impact.
For long screws such as 20 mm, it is necessary to tighten while hitting for about 10 seconds. For this reason, damage to the planetary gear portion and the oil pulse portion is large, and particularly, due to frictional heat generated in each portion, deterioration of lubricating oil applied to the planetary gear,
This means that the internal oil viscosity decreases due to seizure between gears, premature wear, and an increase in the temperature of the oil pulse portion, resulting in an inferior durability, such as a decrease in output and oil leakage occurring early.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned drawbacks, and to be used in construction where the condition of a compressed air source is poor. It is to provide.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to arrange an air motor, a planetary gear unit and an oil pulse unit in series with their respective rotation axes coincident with each other. A first exhaust passage communicating with
This is achieved by providing a second exhaust passage communicating the outer peripheral space of the planetary gear portion and the outer peripheral space of the oil pulse portion.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pneumatic screwdriver according to the present invention will be described below with reference to FIGS.

In FIG. 1, an air supply port 4 connected to a compressed air source such as a compressor via an air hose or the like (not shown) is provided in a motor housing 2 and a clutch housing 3 which form outer shells of the screw tightening machine main body 1; A pressure accumulating chamber 5 provided in communication with the air port 4, an air supply valve 7 for selectively controlling communication between the pressure accumulating chamber 5 and the air motor 6, and rotation by compressed air supplied from the air supply valve 7. An air motor 6 having a rotor 8, an exhaust passage 10 for guiding air exhausted from an exhaust hole 9 of the air motor 6 to outside air, a planetary gear unit 11 arranged on a rotation axis of the rotor 8 to reduce the rotation of the rotor 8,
An oil pulse unit 12 arranged on the rotation axis of the planetary gear unit 11 for converting the rotational torque of the planetary gear unit 11 into a percussion torque
Etc. are accommodated.

The planetary gear unit 11 includes a sun gear 13 integrally mounted on the tip of the rotor 8, a planetary gear 14 meshing with the sun gear 13, an internal gear 15 meshing with the planetary gear 14, and a planetary gear 14 And a planetary gear frame 16 that rotates while being reduced in speed.

On the other hand, the oil pulse portion 12 is fitted to the planetary gear frame 16 and rotates so that the liner case 1 rotates.
7, a liner 18 provided integrally with the liner case 17 therein, an anvil 19 provided rotatably coaxially within the liner 18, and a spring housed in a groove provided in the anvil 19. The blade 20 is constantly urged in the outer peripheral direction by the blade 20 and is in contact with the inner peripheral surface of the liner 18. Liner 18 and anvil 1
9 is sealed with oil, and when the liner 18 rotates, the seal surface (not shown) formed on the inner peripheral surface of the liner and the seal surface formed on the outer peripheral surface of the anvil 19 and the blade 21 match. A pulse-like impact torque is generated in the anvil 19. One end of the anvil 19 is rotatably supported by the clutch housing 3 and protrudes outward from the clutch housing 3, and a tip of the anvil 19 is detachably attached to a driver bit (not shown).

The motor housing 2 and the clutch housing 3 are connected via a cylindrical housing adapter 22 having a full thread formed on the outer periphery. Further, the housing adapter 22 is fastened to the motor housing 2 side to press and fix the planetary gear portion 11 and the air motor 6 so that they cannot move in the axial direction.

In FIG. 2 to FIG. 6, the air motor 6 and the planetary gear portion 11 are supported by the inner wall of the motor housing 2 so as not to move in the radial direction, and the inner wall of the motor housing 2 has an exhaust hole 9 formed in the air motor 6. Starting from the position, the entire circumference or a part of the undercut space 23 is continuously formed up to the lowermost support portion of the planetary gear portion 11. The bore space 23 reduces the exhaust discharged from the exhaust hole 9 downward, that is, from the air motor 6 to the planetary gear unit 11 and the oil pulse unit 12.
The first exhaust passage of the present invention is configured to flow to the first exhaust passage. The lower end of the first exhaust passage communicates with the exhaust passage 10 via the lateral hole 24.

The gap between the inner wall of the clutch housing 3 and the outer periphery of the oil pulse section 11 constitutes a second exhaust passage of the present invention, and the first exhaust passage is provided through a plurality of holes 22 a provided on the upper surface of the housing adapter 22. It communicates with the passage.

Next, the operation of the pneumatic screwdriver configured as described above will be described with reference to FIG.

When the trigger 26 is pulled, the air supply valve 7 opens, and the compressed air in the accumulator 5 flows into the air motor 6 through the air inlet passage 27 to rotate the rotor 8. The rotation of the rotor 8 is reduced by the planetary gear unit 11 to rotate the planetary gear frame 16. When the liner case 17 and the liner 18 rotate together with the planetary gear frame 16, a pulsed impact energy is applied to the anvil 19 once per rotation to rotate the anvil 19 due to an increase in internal oil pressure. Thus, the screw is tightened by the driver bit attached to the tip of the anvil 19.

Next, the flow of exhaust gas discharged from the air motor 6 during this time will be described. The exhaust gas consumed by the rotation of the rotor 8 flows out of the exhaust hole 9 of the air motor 6 and
5, and in FIG. 5, the planetary gear portion 11 is cooled by exhaust gas flowing through a hollow space 23 provided on the entire outer periphery of the planetary gear portion 11, and partly flows from the lateral hole 24 to the exhaust passage 10. A part of the oil pulse flows into FIG. 6 and passes through the hole 22a of the housing adapter 22 shown in FIG. The exhaust gas flowing into the lower end of the portion 11 flows upward again along the second exhaust passage, passes through the hole 22a of the housing adapter 22, and flows into the exhaust passage 10 through the lateral hole 24 while further cooling the oil pulse portion 11. Finally, it is released to the outside air.

[0017]

As described above, according to the present invention, the air motor, the planetary gear section, and the oil pulse section are coaxially arranged in series, and the exhaust hole of the air motor, the outer space of the planetary gear section, and the outer space of the oil pulse section are provided. Are connected in series by an exhaust passage, and exhaust is exhausted from the air motor when the screw is tightened.
The planetary gear section and oil pulse section are always cooled, so there is almost no heat generation in each section, deterioration of the lubricating oil in the planetary gear section due to heat generation, seizure between gears, early wear,
Further, it is possible to provide a durable pneumatic screw tightening machine with reduced output of the oil pulse portion and early oil leakage.
Also, the adoption of a durable planetary gear unit provides a small, lightweight pneumatic screwdriver with an oil pulse mechanism that can be used without increasing the size of the air motor unit even in buildings where the conditions of the compressed air source are poor. it can.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a pneumatic screwdriver according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view taken along line CC of FIG. 1;

FIG. 5 is a sectional view taken along line DD of FIG. 1;

FIG. 6 is a sectional view taken along line EE of FIG. 1;

FIG. 7 is a front sectional view showing an example of a conventional screw tightening machine.

[Explanation of symbols]

1 is a screw tightening machine main body, 4 is an air supply port, 6 is an air motor, 7
Is an air supply valve, 9 is an exhaust hole, 10 is an exhaust passage, 11 is a planetary gear section, 12 is an oil pulse section, 18 is a liner, 19 is an anvil, 20 is a spring, and 21 is a blade.

Claims (4)

[Claims] 1. An air supply port connected to a compressed air source, an air motor rotated by compressed air, an oil pulse portion transmitting rotation of the air motor to a driver bit, and an air motor provided between the air supply port and the air motor. Having an air supply valve for controlling the communication between the air supply port and the air motor, an exhaust hole provided in the air motor, and an exhaust passage for guiding exhaust discharged from the exhaust hole, and tightening the screw by rotating the driver bit. A pneumatic screwdriver, wherein a planetary gear portion for reducing the rotation of the air motor is provided between the air motor and the oil pulse portion, and the rotation axes of the air motor, the planetary gear portion and the oil pulse portion are substantially aligned with each other. Pneumatic screw tightening machine. 2. A method according to claim 1, wherein a first exhaust passage is provided on an outer periphery of the planetary gear portion, and exhaust gas discharged from an exhaust hole of the air motor flows along an outer periphery of the planetary gear portion via the first exhaust passage. The pneumatic screwdriver according to claim 1, characterized in that: 3. The pneumatic screwdriver according to claim 2, wherein a second exhaust passage is provided on an outer periphery of the oil pulse section, and the second exhaust passage is communicated with the first exhaust passage. 4. Exhaust gas discharged from an exhaust hole of the air motor is sent to a tip end side of an oil pulse portion through a first exhaust passage and a second exhaust passage, and then returned to a tip end side of a planetary gear portion through a second exhaust passage. 4. The pneumatic screwing machine according to claim 3, wherein the planetary gear portion and the oil pulse portion are cooled after being discharged outside the machine body.