JPH01121181A - Power wrench with torque measuring device - Google Patents

Abstract

PURPOSE: To display fastening torque immediately and facilitate handling of a power wrench by disposing a non-electric torque measuring piece on a casing, and fitting a torque display, device for displaying the measurements of the measuring piece integrally with the measuring piece. CONSTITUTION: With an operation handle 14 turned clockwise and counter-clockwise turning of a casing 6 inhibited by a reaction arm 11 constrained with an anchorage (b), the input torque of the operation handle 14 is increased with a planetary gear mechanism 8, and transmitted to a socket 17 mounted on an output shaft 3. The socket 17 is turned clockwise to tighten a bolt (a). The reaction torque acting on a casing arm 10 in proportional to tightening torque is measured with a load measuring piece 12. The measured reaction torque is converted and represented as a torque value displaying the tightening torque on a torque display device 13.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is capable of strongly tightening objects such as bolts and nuts by increasing input torque using an operating handle, etc.
This article relates to a planetary gear mechanism type power wrench used for disassembly.

The present invention also relates to the above-mentioned power wrench to which a torque measurement function is added.

(Prior art and problems to be solved by the invention) Conventionally, when tightening objects such as bolts and nuts using torque for large tightening, and moreover, for tightening to a predetermined level, it is necessary to combine a power wrench with a torque wrench. was being carried out. At this time, the following relationship holds between the input torque value Ti3 of the torque wrench, the torque value To for tightening the object to be fastened, and the power increase ratio a of the power wrench.

To= a Ti −−−−−−−−−−−−−−−−
−−−−−−−−−−−(1) Also, the power increase ratio a can be expressed by the following formula, which is the theoretical power increase ratio ao obtained by theoretical calculation multiplied by the mechanical efficiency η of the planetary gear mechanism of a power wrench, etc. can.

a−ηa o −−−−−−−−−−−−−−−−−
--(2) By the way, conventionally it is assumed that a=ao, and To
= a.

The torque value TO was calculated for tightening as Ti, but even when η is considerably smaller than 1 due to wear of the gears in the planetary gear mechanism, deterioration of the lubrication condition, etc. When a.

Predetermined tightening was based on the torque value of the object to be fastened. However, the actual tightening torque value at this time was significantly insufficient compared to that obtained by calculation (1
If aoTi<<aoTi), there is a problem that accurate fastening work cannot be performed.

Further, in the conventional method, the input torque value Ti of the torque wrench has to be calculated, which is troublesome.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a power wrench equipped with a torque measuring device that is easy to handle and allows immediate visual inspection of the input torque value, while solving the problems of the prior art described above.

(Means for Solving the Problems) In order to achieve the above object, the present invention has a sun gear 2 attached to an input shaft 1 that receives rotational force, as illustrated in the illustrated embodiment.
A planetary gear 4. is attached to the output shaft 3 which rotates the fastened object a.
A carrier 5 supporting the planetary gears 4.4 is attached to a casing 6 supporting the input shaft 1 and the output shaft 3.
A power wrench equipped with a planetary gear mechanism 8 each having internal gears 7 for guiding the power wrench, and a reaction force receiving part 9 for stopping the rotation of the casing 6 by stopping the rotation of the casing 6 on a fixed object outside the power wrench. In the wrench, a non-electrical torque measuring element 12 for measuring the torque acting on the casing 6 is disposed on the casing 6 or a member 10 that rotates in the same manner as the casing, and the measured value of the non-electrical torque measuring element 12 is measured. The torque display device 13 for display is connected to the non-electric torque measuring element 1.
It is characterized by being provided integrally with 2.

(Embodiment) The illustrated embodiment has a square fitting hole 15 on the top surface of the input shaft 1 that fits into the square drive 16 of the operating handle 14. ) can be taken into the input shaft 1, and a socket 17 can be removably attached to the output shaft 3, and an object a to be fastened such as a bolt or nut can be rotated through this socket 17. can be tightened or disassembled.

A sun gear 2 is provided on the input shaft, a carrier 5 is provided on the output shaft 3, and the carrier 5 supports four planetary gears 4, 4, . . . . The planetary gear 4 meshes with the outer periphery of the sun gear 2 and also meshes with an internal gear 7 formed on the inner surface of the casing 6, and is guided by the internal gear 7 to revolve around the sun gear 2. Both the input shaft 1 and the output shaft 3 are supported by a casing 6.

The casing 6 is integrally provided with a casing arm (a member that rotates in the same manner as the casing) 10 that protrudes in the radial direction, while a reaction force receiving arm 11 that protrudes in the radial direction around the output shaft 3 is rotatable. It is supported. The casing arm 10 and the reaction force receiving arm 11 are arranged in a plane where they abut each other, and the compressive force acting between these abutting surfaces is measured (tensile force may also be measured; will ultimately measure the torque acting on the casing 6.

) A load measuring element (non-electrical torque measuring element) 12 is provided. Specifically, a spring type compressive force measuring device is attached to the casing arm 10.

The compressive force measured by the load measuring head 12 rotates the pointer 18 of the dial gauge type torque display device 130 by a predetermined amount. The scale 19 of the torque display bag W13 displays a value obtained by converting the compressive force into a tightening torque value using a predetermined calculation formula (see formula (3)). Incidentally, the torque display device 13 is integrally attached on the load measuring head 12.

Next, the operation of the power wrench of the present invention will be explained.

For example, to explain the case where bolt a is tightened clockwise using torque, first, the casing 6
After locking the reaction force receiving arm 11 to a fixed object b (FIG. 2) outside the power wrench, the operation handle 14 is rotated clockwise (a latent type operation handle When using, set it so that it can rotate freely in the counterclockwise direction.) At this time, the casing 6 and, by extension, the casing arm 10 try to rotate counterclockwise, but this rotation is blocked by the reaction force receiving arm 11 restrained by the fixed object. Therefore, the input torque of the operating handle 14 is amplified by the planetary gear mechanism 8, transmitted to the socket 17 attached to the output shaft 3, and rotated clockwise to tighten the socket (a).

At this time, when tightening the bolt a, the following equation holds between the torque To and the reaction torque Tc of the casing arm 10.

To= r) c (ao -1) Tc------
(3) Here, ηC is the mechanical efficiency between the casing arm 10 and the output shaft 3, and ao is the theoretical amplification ratio, which is a constant.

The reaction torque Tc expressed by the equation (3) acts on the load measuring element 12 as a compressive force, which is converted and displayed on the torque display device 13 as a torque value indicating tightening torque.

Since the frictional portion in the torque transmission path between the casing arm 10 and the output shaft 3 is smaller than the frictional portion in the torque transmission path between the input shaft 1 and the output shaft 3, the ηC is (see equation (2)), it is possible to bring the value closer to 1, and the fluctuation value of ηC after long-term use can also be reduced. Therefore, the torque value displayed on the torque display device 13 can be close to the actual tightening torque value, and this can be made highly reliable (by considering ηC in advance). (If the display torque value of the torque display device 13 is determined in advance, the -layer reliability can be improved.) Accurate tightening can be performed.

The present invention can be configured in various ways other than those shown in the above embodiments. For example, the input shaft 1 may have a structure in which a bar handle is directly attached to the input shaft 1, or the input shaft 1 may be configured to accept input torque from an electric drive device, an air drive device, a hydraulic drive device, or the like. Also sun gear 2
, the planetary gears 4.4, . . . , the carrier 5, and the internal gear 7. Of course, the aspect of the planetary gear mechanism 8 is not limited to that shown in the above embodiment. Further, in the above embodiment, the non-electric torque measuring element 12 is provided on the casing arm 10, but it is also possible to provide this on the casing 6. Further, as the non-electric torque measuring element 12, a hydraulic measuring device or the like may be used. Further, the torque display device 13
can be of a type other than a dial gauge type, for example, a digital display type can be adopted. Furthermore, the socket 17 can be integrally formed on the output shaft 3, or a fitting member other than the socket that fits into the object to be fastened a can be attached to the output shaft 3.

(Effects of the Invention) Since the present invention has the above configuration, the following effects can be achieved.

■ When using the power wrench with the torque measuring device of the present invention, it is possible to obtain torque for accurate tightening, and it is easier to perform the work for accurate tightening, compared to a combination of a conventional torque wrench and a power wrench. Can be done. In addition, in the conventional combination of a torque wrench and a power wrench, it was necessary to calculate the input torque value of the torque wrench, but with the device of the present invention, tightening can be performed immediately by displaying the torque value on the torque display device. can be displayed.

■ The power wrench with a torque measuring device of the present invention has a non-electric torque measuring head and a torque display device is integrally provided with the torque measuring head, so it is separate from the power wrench. It is not necessary to connect the electric measuring device/display device with a cord, making handling convenient and reducing costs.

[Brief explanation of the drawing]

FIG. 1 is a partially longitudinal front view of an embodiment of the present invention, and FIG. 2 is a partially transverse plan view thereof. 1-・・−−−−−−−−−−−−−−・−・−・−
−−−One person power axis 2-11−・−−−−−−−−−−−
−−−1・−1−−−Sun gear 3−・−・・・・−−
−−−−−−−−−−−111~Output shaft 4−・・−・−
・−1−−−−−−−−−−−−− Planetary gear 5 ・
・−−−−−−−−−−−−−−−−−−−−−−
−・Carrier 6−・−−−−−−−m−−−・−・−
...-1--Casing 7--
−−−−−−−−−−−−−・−Internal gear 8 ・−・−・
-・・−・・−・−−−−−−−− Arm 12---1------
・−・−・−・−11−−Non-electric torque measuring element 13−
−−−−・−−−−11111・−・−・−・・・・・−
Torque display device a-・-・-・・-・・・・−・−・
− Fastened object b −−−−−−−−−−−−−−−
−−−−−−− Fixed property agent Patent attorney Ishihara
Victory

Claims (1)

[Claims] (1) A sun gear is placed on an input shaft that receives rotational force, a carrier that supports a planetary gear is placed on an output shaft that rotates an object to be fastened, and the planetary gear is guided to a casing that supports the input shaft and the output shaft. In a power wrench, the power wrench is equipped with a planetary gear mechanism each having internal gears, and a reaction force receiving part that stops rotation of the casing by locking it to a fixed object outside the power wrench. A non-electrical torque measuring element to be measured is disposed on the casing or a member that rotates in the same manner as the casing, and a torque display device for displaying the measured value of the non-electrical torque measuring element is integrated into the non-electrical torque measuring element. A power wrench with a torque measuring device that is characterized by being equipped with a torque measuring device.