JP3128539U - Measuring device for measuring angular displacement of output shaft of impact nut runner during tightening of threaded joint, and impact nut runner equipped with said measuring device - Google Patents

Abstract

A measuring device capable of obtaining an angular displacement of an output shaft during tightening without using an angle sensing means on the output shaft, and an impact nutrunner provided with the measuring device.
An impact nut runner includes a housing having a handle, a throttle valve, a pressurized air introduction connecting portion, and an exhaust port. The nut runner further includes a pneumatic vane motor 20 having a rotor 21 and a fixed cylinder 22, and a pulse unit 23 having an output shaft 24 for connection to a screw component 25 via a nut socket 26. In addition, the pulse unit 23 includes a cylindrical inertial drive member 27, which includes a hydraulic fluid chamber 29 that is firmly connected to the rotor 21 of the motor and partially defined by the front end wall 30. ing.
[Selection] Figure 1

Description

  The present invention uses the information from the angle sensing device arranged to detect the angular displacement of the inertial drive member of the impact nut runner, the angular displacement of the output shaft of the impact nut runner, i.e. the screw during the tightening process. The present invention relates to a measuring device for measuring the angular displacement of a joint and an impact nutrunner provided with the assumed device.

In the impact nut runner, there is a problem of obtaining accurate information on the angular displacement of the output shaft, that is, the angular displacement of the threaded joint during the tightening process. In the prior art, an impact nut runner in which an angle sensor for obtaining a signal related to a rotation angle is provided on an output shaft is disclosed. For example, see US Pat. No. 6,341,533 (Patent Document 1).
US Pat. No. 6,341,533 International Publication WO02 / 083366

  With this type of angle sensing device, there is a problem that the outer diameter of the nut runner is increased, and in particular, there is a problem that the length of the tool is increased. In particular, in an impact nut runner in which an angle sensor for detecting the angular displacement of the inertial drive member is already provided for the purpose of torque calculation, adding an extra angle sensor to the output shaft It is undesirable and complicates the nut runner. For example, International Publication WO02 / 083366 (Patent Document 2) is referred to.

The main object of the present invention is to provide a measuring device capable of obtaining the angular displacement of the output shaft during tightening without using an angle sensing means on the output shaft, and an impact nut runner equipped with the measuring device. In other words, the angular displacement between the output shaft and the threaded joint is immediately calculated from the angle signal provided by the angle sensing device that detects the angular displacement of the inertial drive member of the impact unit.
Further objects and advantages of the present invention will become apparent from the following description and the utility model registration claims.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
The measuring device according to the invention is applied to an impact nutrunner having a specific angle sensing means, i.e. an angle sensor associated with the inertial drive member of the torque impact generating pulse unit. In order to understand the improvement by this invention, this kind of impact nutrunner is demonstrated in detail below.

  The impact nut runner schematically shown in FIG. 1 includes a housing 10 having a handle 11, a throttle valve 12, a pressure air introduction connecting portion 13, and an exhaust port 14. The nut runner further includes a pneumatic vane motor 20 having a rotor 21 and a fixed cylinder 22, and a pulse unit 23 having an output shaft 24 for connection to a screw component 25 via a nut socket 26.

  In addition, the pulse unit 23 includes a cylindrical inertia drive member 27, and the inertia drive member 27 includes a hydraulic fluid chamber 29 that is firmly connected to the rotor 21 of the motor and partially defined by the front end wall 30. ing. A rear end portion 34 is formed on the output shaft 24, and this rear end portion 34 extends into the hydraulic fluid chamber 29 and receives a torque impact from the impact generating mechanism. The latter comprises two opposing pistons 31a and 31b, which are reciprocated in the lateral bore 33 of the output shaft 24 by two actuating balls 32a and 32b. The balls 32 a and 32 b engage with a cam (not shown) on the inner cylindrical surface of the drive member 27. The pistons 31 a and 31 b form a high-pressure chamber for generating a torque impact between them in the hole 33.

  This type of pulse unit has already been disclosed, for example, in U.S. Pat. No. 5,092,410 and does not form part of the present invention and will not be described in further detail.

  In order to detect the rotational movement of the rotating part of the torque transmitting tool, the inertial drive member 27 is provided with a ring element 35 made of a resin material. The ring element 35 is magnetized by a number of parallel bands 36 corresponding to magnetic poles arranged at equal intervals on the entire outer periphery thereof (see FIG. 3a). As shown in FIG. 2, the ring element 35 is fixed to the inertial drive member 27 by two screws 37 and forms a rigid unit with the inertial drive member 27.

  Further, the angle encoder includes a fixed sensor unit 38 disposed on the circuit board 39. The fixed sensor unit 38 is configured to detect the rotation of the inertial drive member 27 when the magnetic band 36 of the ring element 35 passes through the sensor unit 38. The circuit board 39 is fixed to the tool housing 10, and the housing 10 is also provided with power supply means connected to the motor 20. The sensor unit 38 is configured to transmit a signal corresponding to the number of times the magnetic band 36 passes to an external control unit 40 connected to the sensor unit 38. The control unit 40 uses the signal from the sensor unit 38 and the signal from the total moment of inertia value as a tool-related coefficient to calculate arithmetic means for measuring the magnitude of the delay of the rotating member in addition to the transmission torque. It has. Several signal processing electronics can also be provided on the nut runner itself.

  The sensor unit 38 includes a plurality of elongated sensing loops 42. These sensing loops 42 are arranged in parallel to obtain a phase lag signal from the sensor unit 38 and are spaced apart from one another by a distance different from the spacing of the magnetic bands 36 on the ring element 35. This phase delay makes it possible to measure the direction in which the inertia member 27 rotates.

  The angle encoder described above is particularly suitable for this device because of its robust design and very good angular resolution. This angle encoder is not new per se and is commercially available as Series EK 622 Encoder Kit from Admotec (Advanced Motion Technologies) in the United States.

  During operation, the output shaft 24 is connected to the threaded part 25 via a nut socket 26 and power pressure air is supplied to the motor 20 to send drive torque to the pulse unit 23. As long as the torque resistance from the screw component 25 is below a certain level, the pulse unit 23 sends continuous motor torque directly to the output shaft 24 without causing any impact. As the screw component 25 stops gradually and the torque resistance rises above the specified level, the pulse unit 23 begins to convert continuous motor torque into torque shock. As a result, the inertial drive member 27 is continuously accelerated during a complete rotation between two successive impacts, and sends kinetic energy to the output shaft 24 via the impact mechanism 23. The torque sent via this kinetic energy is several times higher than the continuous torque sent by the motor 20 and achieves a gradual tightening of the screw part 25.

  By detecting the movement of the rotating part using the magnetized ring element 35 and the sensor unit 38, the magnitude of the delay of the rotating part in addition to the rotation speed can be calculated, and the calculated magnitude of the delay, By using the drive member 27 and the total moment of inertia of the part cooperating with the drive member of the tool, the torque transmitted to the screw component 25 can be determined.

According to the present invention, it is also possible to measure the angular displacement between the output shaft and the screw component by using the signals generated by the angle sensors 35 and 38. Rotational movement phi _D of the driving member 27 between the impact occurs, one complete rotation, i.e., to 360 °, since it is the result displacement [Delta] [phi ₀ a value obtained by adding the drive shaft, the total output axis displacement phi _0Tot is First, the total rotation angle φ _Dtot of the drive member 27 is determined, and then the angle obtained by subtracting one complete rotation: 360 ° from the total angle φ _Ntot : N _tot · 360 ° of the total number of complete rotations. Can be calculated by subtracting. This can be expressed as:
φ _0tot = φ _Dtot − (N _tot −1) · 360
Since the first impact can be preceded by an unknown acceleration angle of the drive member, one full rotation needs to be subtracted.

Since the initial stage of tightening is very fluid due to the setting of the threaded joint or the like, the total angular displacement φ _Dtot of the drive member 27 in addition to the total number of impacts is from the very first impact during the tightening process. It cannot be calculated. In other words, the total drive member displacement φ _Dtot is calculated from a predetermined reference torque level T _t that meets a certain percentage of the desired final torque level T _f , for example 50%.

  The present invention uses the signal sent by the angle sensor, which is provided on the impact unit drive member and used for other purposes such as calculation of the transmission output torque of the nut runner, to change the angular displacement of the output shaft. There is an effect that measurement can be performed without hindrance, and no extra angle sensing means is required for enlarging the outer shape of the nut runner or complicating the structure.

It is a partial section side view of an impact nut runner provided with a measuring device concerning the present invention. FIG. 2 is a longitudinal sectional view of an impact nut runner of the type shown in FIG. 1 connected to a threaded part. (A) is a perspective view of the ring element which forms a part of rotation detection apparatus of the tool of FIG. 1, (b) is a perspective view of the sensor unit which forms a part of rotation detection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Housing 11 Handle 12 Throttle valve 13 Pressure air introduction connection part 14 Exhaust port 20 Vane motor 21 Rotor 22 Fixed cylinder 23 Pulse unit 24 Output shaft 25 Screw part 26 Nut socket 27 Inertial drive member 29 Hydraulic fluid chamber 30 Front end wall 31a Piston 31b Piston 32a Actuating ball 32b Acting ball 33 Lateral hole 34 Rear end portion 35 Ring element 36 Parallel band 37 Screw 38 Fixed sensor unit 39 Circuit board 40 External control unit 42 Sensing loop

Claims (4)

An impact unit (23) having a motor driven inertial drive member (27) for transmitting a torque impact to the output shaft (24) for every complete rotation;
For an impact nutrunner with an angle sensing device (35, 38) arranged to detect the rotational movement (φ _D ) of the inertial drive member (27),
A measuring device for an impact nut runner capable of measuring the angular displacement (φ ₀ ) of the output shaft (24) of the impact nut runner when the threaded joint is tightened to a desired final torque level (T _f ),
A reference torque level (T _t ) that is a basis for detecting the rotational motion (φ _D ) of the inertial drive member (27) is determined,
_Determining the total rotational angle (φ _Dtot ) of the inertial drive member achieved by the total number of torque impacts (N _tot ) calculated from the reference torque level (T _t );
A value obtained by subtracting one complete rotation from the total angle (φ _Ntot ) of the total number of complete rotations (N _tot ) from the total rotation angle (φ _Dtot ) of the inertial drive member (27) calculated from the reference torque level (T _t ). By subtracting ((N _tot −1) · 360 °), the total angular displacement of the output shaft (24) achieved by the total number of torque impacts (N _tot ) calculated from the reference torque level (T _t ) ( A measuring apparatus configured to calculate φ _0tot ). The measuring apparatus according to claim 1, wherein the reference torque level (T _t ) is a predetermined ratio of a desired final torque level (T _f ). An impact unit (23) having a motor driven inertial drive member (27) for transmitting a torque impact to the output shaft (24) for every complete rotation;
Angle sensing device (35, 38) arranged to detect rotational movement (φ _D ) of inertial drive member (27) and impact nut runner when screw joint is tightened to desired final torque level (T _f ) An impact nutrunner comprising a measuring device (40) for measuring the angular displacement (φ ₀ ) of the output shaft (24) of
The measuring device (40)
A reference torque level (T _t ) that is a basis for detecting the rotational motion (φ _D ) of the inertial drive member (27) is determined,
Based on the signal from the angle sensing device,
_Determining the total rotational angle (φ _Dtot ) of the inertial drive member achieved by the total number of torque impacts (N _tot ) calculated from the reference torque level (T _t );
A value obtained by subtracting one complete rotation from the total angle (φ _Ntot ) of the total number of complete rotations (N _tot ) from the total rotation angle (φ _Dtot ) of the inertial drive member (27) calculated from the reference torque level (T _t ). By subtracting ((N _tot −1) · 360 °), the total angular displacement of the output shaft (24) achieved by the total number of torque impacts (N _tot ) calculated from the reference torque level (T _t ) ( An impact nut runner characterized in that φ _0tot ) is calculated. The impact nutrunner according to claim 3, wherein the reference torque level (T _t ) is a predetermined ratio of a desired final torque level (T _f ).

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