JP2015000457A - Fastening device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fastening device having an external diagnostic function capable of confirming simply from the outside whether a torque sensor detects a torque correctly or not.SOLUTION: A connection part 110 positioned on the elongation of a shaft center line C of a driving shaft 93 and on the rear end side is provided on a casing 100. A torque wrench 200 can be mounted on/dismounted from the connection part 110.

Description

  The present invention relates to a tightening device such as a nut runner or an impact wrench.

  Conventionally, as this kind of tightening device, there is one described in JP 2009-113132 A (Patent Document 1).

  In this conventional tightening device, the rotational torque from the air motor is converted into a pulsed hitting torque by the hitting torque generator, and the drive shaft is driven with the pulsed hitting torque, that is, the increased large torque. Then, the screws are tightened. Then, the tightening torque with respect to the screw of the drive shaft is detected by a torque sensor, the rotation angle of the drive shaft is detected by an angle sensor, and the determination unit tightens the screw based on the output of the torque sensor and the angle sensor. It is determined whether or not is properly performed.

JP 2009-113132 A

  However, the conventional tightening device has a problem that when an abnormality occurs in the detection accuracy of the torque sensor, the abnormality cannot be easily detected. Although it is conceivable to provide an internal diagnostic device in the tightening device and constantly check the detection performance of the torque sensor, the internal diagnostic device itself may fail.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a tightening device that is provided with an external diagnostic function and can easily confirm from the outside whether or not the torque sensor correctly detects torque.

In order to solve the above problems, the tightening device of the present invention provides:
A power unit,
An intensifier driven by the power unit;
A drive shaft driven by the force-increasing section;
A casing for receiving at least a force-increasing portion and receiving a reaction force when tightening the drive shaft;
A torque sensor for detecting a reaction force when the drive shaft is tightened;
A torque wrench is detachably connectable on an extension of the shaft center line of the drive shaft and on the rear end side.

  In the tightening device having the above-described configuration, a torque wrench is externally attached to a connecting portion that is located on the rear end side of the drive shaft and that can be detachably connected to the drive shaft. Then, by applying a known torque from the torque wrench to this connecting portion and collating this known torque with the detected torque of the torque sensor, it is externally determined whether or not the torque sensor correctly detects the torque. Easy to check.

  In this way, it is possible to easily check whether the torque sensor is normal or not from the outside of the tightening device, for example, at the start of work.

  Further, since the connecting portion to which the torque wrench can be detachably connected is located on the rear end side of the extension of the axis of the drive shaft, the torque wrench can be easily attached and detached. Can do.

In one embodiment,
The casing is
A fixed portion located outside the drive shaft and fixed to the support member;
A thick-walled portion to which one end in the axial direction opposite to the free end in the axial direction of the internal gear of the force increasing portion is fixed;
It is located between the fixed part and the thick part and on the free end side in the axial direction of the internal gear, the outer diameter is smaller than the outer diameter of the thick part, and more than the thick part. Also has a thin part with a thin thickness,
The torque sensor is provided in the thin portion.

  According to the embodiment, the axial end of the internal gear of the booster is fixed to the thick part of the casing, while the thin part of the casing is located on the free end side of the internal gear, It is not fixed directly to lugia. Therefore, the reaction force transmission path is in the order of the internal gear, the thick portion of the casing to which the integral of the internal gear in the axial direction is fixed, the thin portion, and the fixed portion. That is, since the internal gear is turned back at the thick part and passes through the thin part to become a force transmission path to the fixed part, the overall length of the tightening device is shortened and the sensor provided in the thin part This detection signal is less affected by noise components such as mechanical vibrations and can accurately detect only an accurate reaction force, that is, a tightening force. Therefore, such a torque sensor with high detection accuracy can be subjected to the external diagnosis as described above, and is extremely valuable.

  In addition, since the thin portion has an outer diameter smaller than that of the thick portion and is thinner than the thick portion, the thin portion can be distorted more greatly, and tightening torque can be reduced. More accurate detection is possible.

In one embodiment,
The connecting portion is provided integrally with the casing.

  In this case, since the connecting portion provided integrally with the casing is located on the extension of the axis of the drive shaft, the detected torque of the torque sensor and the applied torque of the torque wrench are 1: 1. Are in a relationship.

  The connecting portion provided integrally with the casing is, for example, a hexagonal head shape or a hexagonal hole shape of a bolt, and the connecting portion is regarded as a part of the casing (not a movable portion). Therefore, it is safe and can be manufactured easily and inexpensively.

In one embodiment,
The connecting portion is provided on the shaft of the power increasing portion exposed from the casing.

  In this case, since the connecting portion is provided on the shaft of the power increasing portion exposed from the casing, a torque proportional to the power increasing ratio of the power increasing portion applied to the shaft of the power increasing portion with a torque wrench is applied to the drive shaft. be able to. Therefore, a large torque applied to the drive shaft can be detected by a torque sensor, and compared with a known torque increase ratio multiplied by a torque wrench, an external diagnosis can be made.

Moreover, the tightening device of the present invention comprises:
A power unit,
An intensifier driven by the power unit;
A drive shaft driven by the force-increasing section;
A casing for receiving at least a force-increasing portion and receiving a reaction force when tightening the drive shaft;
The casing is
A fixed portion located outside the drive shaft and fixed to the support member;
A thick-walled portion to which one end in the axial direction opposite to the free end in the axial direction of the internal gear of the force increasing portion is fixed;
It is located between the fixed part and the thick part and on the free end side in the axial direction of the internal gear, the outer diameter is smaller than the outer diameter of the thick part, and more than the thick part. Also has a thin part with a thin thickness,
A torque sensor is provided in the thin portion.

  The tightening device having the above-described configuration has an advantage that the tightening torque can be detected with high accuracy and the total length is short.

  According to this invention, it can be easily confirmed from the outside of the tightening device whether or not the torque sensor of the tightening device correctly detects the torque.

It is a partial cross section front view of the clamping device of a 1st embodiment of this invention. It is a figure explaining the external diagnosis of the clamping apparatus of the said 1st Embodiment. It is a partial cross section front view of 2nd Embodiment.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(First embodiment)
As shown in FIG. 1, a nutrunner as an example of a tightening device includes an air motor part 94 as an example of a power part, a spur gear mechanism 99 and planetary gear mechanisms 91 and 92 as examples of a booster part, a drive And a shaft 93. The output of the air motor 94 is decelerated and increased by the spur gear mechanism 99 and the planetary gear mechanism 91, and further decelerated and increased by the planetary gear mechanism 92. A planetary gear 97 that meshes with the sun gear 95 and the internal gear 96 of the planetary gear mechanism 92 is supported by a carrier 98 that is the base of the drive shaft 93.

  In the first embodiment, the planetary gear mechanisms 91 and 92 constitute a two-stage planetary gear mechanism, but a one-stage planetary gear mechanism may be used.

  One end of the internal gear 96 in the axial direction is fixed to the thick portion 101 of the casing 100 with a bolt 119, while the other end of the internal gear 96 in the axial direction is a free end and is fixed to another member. It has not been.

  The portion of the casing 100 outside the planetary gear mechanism 92 is the thick portion 101, and one end (rear end) of the internal gear 96 in the axial direction is formed on the thick portion 101 of the casing 100 as described above. It is fixed.

  On the other hand, the fixing portion 103 of the casing 100 is fixed to a support member (not shown).

  The thin part 102 between the thick part 101 and the fixed part 103 of the casing 100 is thinner than the thick part 101 and is located radially inside the outer diameter of the thick part 101. It has become. That is, the thin portion 102 is thinner than the thick portion 101 and has an outer diameter that is smaller than the outer diameter of the thick portion 101. The thin portion 102 is positioned on the free end side that is the other end in the axial direction of the internal gear 96, and the other end in the axial direction of the internal gear 96 is not fixed to the thin portion 102. A strain sensor 105 such as a strain gauge is provided on the outer surface of the thin portion 102 as an example of a torque sensor that detects a reaction force when the drive shaft 93 is tightened. As a result, the internal gear 96 that receives the reaction force of the tightening torque of the drive shaft 93 causes a relatively large distortion in the thin-walled portion 102. This distortion is detected by the distortion sensor 105, and the tightening torque is accurately determined. It can be detected. More specifically, one end of the internal gear 96 in the axial direction is fixed to the thick portion 101 of the casing 100, while the other end of the internal gear 96 in the axial direction is not fixed to the thin portion 102 of the casing 100. . Therefore, the reaction force transmission path is in the order of the internal gear 96, the thick portion 101 of the casing 100 to which the integral of the internal gear 96 in the axial direction is fixed, the thin portion 102, and the fixed portion 103. Accordingly, the internal gear 96 is folded back at the thick portion 101 and passes through the thin portion 102 to be a force transmission path to the fixed portion 103. Therefore, the detection signal of the strain sensor 105 provided on the thin portion 102 is In addition, the influence of noise components such as mechanical vibrations is small, and it is possible to detect only the exact reaction force during tightening, that is, the tightening force. Furthermore, since the force transmission path is a path that folds back at the thick part 101 and transmits the force to the thin part 102, the total length of the nut runner can be shortened.

  Although not shown, the outer diameter of the thin portion 102 may be the same as the outer diameter of the thick portion 101.

  Further, the casing 100 is integrally provided with a hexagonal head 110 as an example of a connecting portion located on the extension of the axis C of the drive shaft 93 and on the rear end side. The hexagonal head 110 may be fixed to the casing 110 and integrated so as not to allow relative rotation. The hexagonal head 110 can be detachably fitted to the torque wrench shown in FIG.

  In the nutrunner having the above configuration, when an electromagnetic valve (not shown) is opened, high pressure air is supplied to the air motor 91 and the air motor 94 is driven, the output of the air motor 94 is the spur gear mechanism 99. Further, the planetary gear mechanisms 91 and 92 further increase the force to rotate the drive shaft 93, and a nut (not shown) at the tip of the drive shaft 93 is tightened.

  When the nut is tightened by the drive shaft 93, one end in the axial direction of the internal gear 96 is fixed to the thick portion 101 of the casing 100, so that a large reaction force of the tightening force of the drive shaft 93 is applied to the thickness of the casing 100. Although it is received by the meat portion 101, it is thick, so that it has sufficient strength and little vibration.

  On the other hand, at this time, the thin portion 102 between the thick portion 101 and the fixed portion 103 of the casing 100 is thinner and smaller in diameter than the thick portion 101, so that it is sufficiently distorted with respect to the tightening force. The strain sensor 105 can detect the large strain of the thin-walled portion 102 more accurately with less vibration and the like, and can accurately detect the tightening force. More specifically, one end of the internal gear 96 in the axial direction is fixed to the thick portion 101 of the casing 100, while the other end of the internal gear 96 in the axial direction is not fixed to the thin portion 102 of the casing 100. . Therefore, the reaction force transmission path is in the order of the internal gear 96, the thick portion 101 of the casing 100 to which the integral of the internal gear 96 in the axial direction is fixed, the thin portion 102, and the fixed portion 103. Accordingly, the internal gear 96 is folded back at the thick portion 101 and passes through the thin portion 102 to be a force transmission path to the fixed portion 103. Therefore, the detection signal of the strain sensor 105 provided on the thin portion 102 is In addition, the influence of noise components such as mechanical vibrations is small, and only an accurate reaction force, that is, a tightening force can be detected. Furthermore, since the force transmission path is a path that folds back at the thick part 101 and transmits the force to the thin part 102, the total length of the nut runner can be shortened.

  Next, an external diagnosis is performed as follows, for example, as to whether the strain sensor 105 serving as a torque sensor correctly detects torque at the start of work or the like.

  As shown in FIG. 2, a cap 201 of a torque wrench 200 is externally fitted to a hexagonal head 110 of the casing 100 located on the extension of the axis C of the drive shaft 93 and on the rear end side. And attach. Then, a known torque is applied to the hexagonal head 110 from the torque wrench 200 and the casing 100 is twisted. Since the fixing portion 103 of the casing 100 is fixed to a support member (not shown), the casing 100 is twisted with the known torque. By collating this known torque with the detected torque output from the strain sensor 105, it can be easily diagnosed and confirmed from the outside whether or not the strain sensor 105 as the torque sensor has correctly detected the torque.

  In this way, it is possible to easily confirm whether or not the strain sensor 105 is normal from the outside of the nutrunner, for example, at the start of work.

  The hexagonal head 110 to which the torque wrench 200 can be detachably connected is positioned on the extension of the axis C of the drive shaft 93 and on the rear end side. Operation can be performed easily.

  Further, since the hexagonal head 110 is regarded as a part of the casing 100 (not a movable part), it is safe, and can be manufactured easily and inexpensively.

  Further, since the hexagonal head 110 provided integrally with the casing 100 is located on the extension of the axis C of the drive shaft 93, the detected torque of the strain sensor 105 and the applied torque of the torque wrench 200. Is in a 1: 1 relationship.

  In the first embodiment, the connecting portion provided integrally with the casing 100 is configured by the hexagonal head 110. For example, the connecting portion may be configured by a quadrangular head, a hexagonal hole shape, or the like. Good. The point is that it can be detachably fitted to the torque wrench.

(Second Embodiment)
As shown in FIG. 3, the nut runner as the fastening device of the second embodiment is different from the first embodiment only in the configuration of the connecting portion. Therefore, in the second embodiment of FIG. 3, the same or similar components as those of the first embodiment of FIGS. 1 and 2 are denoted by the same reference numerals as those of FIGS. Description is omitted and only different components will be described below.

  In the second embodiment, the shaft 199 on the input side of the planetary gear mechanism 91, which is an example of the boosting portion located on the drive shaft 93 on the extension of the axis C and on the rear end side, that is, the spur gear mechanism 99. The output side shaft 199 is exposed from the casing 100, and a connecting portion 120 made of a fitting hole such as a hexagonal hole or a quadrangular hole is provided at the tip of the shaft 119. The connecting portion 120 is detachably fitted to a hexagonal or quadrangular fitting protrusion 212 of the torque wrench 200.

  In the above configuration, the tip of the drive shaft 93 is fitted and fixed in a fitting hole such as a jig (not shown) so that the air motor unit 24 can be unloaded and freely rotated. At 200, the connecting portion 120 of the shaft 199 is twisted with a known torque. Then, since the connecting portion 120 is provided on the shaft 199 of the planetary gear mechanisms 91 and 92 as the boosting portion, the known torque applied to the connecting portion 120 by the torque wrench 200 is converted into the planetary gear mechanisms 91 and 91 as the boosting portion. The torque is increased to a torque proportional to the increase ratio of 92 and applied to the drive shaft 93. Therefore, the large torque applied to the drive shaft 93 is detected by the strain sensor 105 (see FIG. 1) as a torque sensor via the internal gear 96 (see FIG. 1). Compared with the known torque increase ratio times of the torque wrench 200, it can be easily externally diagnosed whether or not the strain sensor 105 correctly detects the torque.

  In addition, you may make it provide a cap in the location where the said connection part 120 is exposed.

  In the first and second preferred embodiments, the air motor unit 24 is used as the power unit. However, an electric motor or a hydraulic motor may be used as the power unit.

  In the first and second preferred embodiments, the planetary gear mechanisms 91 and 92 and the spur gear mechanism 99 are used as the force-increasing part, but a pulse-like impact torque as in Patent Document 1 is generated as the force-increasing part. A striking torque generator may be used. This impact torque generating device may be a hydraulic type or a mechanical type.

91, 92 Planetary gear mechanism 93 Drive shaft 94 Air motor part 99 Spur gear mechanism 100 Casing 101 Thick part 102 Thin part 103 Fixed part 105 Strain sensor

Claims (5)

A power unit,
An intensifier driven by the power unit;
A drive shaft driven by the force-increasing section;
A casing for receiving at least a force-increasing portion and receiving a reaction force when tightening the drive shaft;
A torque sensor for detecting a reaction force when the drive shaft is tightened;
A tightening apparatus comprising: a connecting portion that is detachably connectable with a torque wrench and is located on the rear end side of the drive shaft on the extension of the axis. The fastening device according to claim 1,
The casing is
A fixed portion located outside the drive shaft and fixed to the support member;
A thick-walled portion to which one end in the axial direction opposite to the free end in the axial direction of the internal gear of the force increasing portion is fixed;
It is located between the fixed part and the thick part and on the free end side in the axial direction of the internal gear, the outer diameter is smaller than the outer diameter of the thick part, and more than the thick part. Also has a thin part with a thin thickness,
The tightening device, wherein the thin portion is provided with the torque sensor. The tightening device according to claim 1 or 2,
The fastening device is characterized in that the connecting portion is provided integrally with the casing. The tightening device according to claim 1 or 2,
The fastening device according to claim 1, wherein the connecting portion is provided on a shaft of a power increasing portion exposed from the casing. A power unit,
An intensifier driven by the power unit;
A drive shaft driven by the force-increasing section;
A casing for receiving at least a force-increasing portion and receiving a reaction force when tightening the drive shaft;
The casing is
A fixed portion located outside the drive shaft and fixed to the support member;
A thick-walled portion to which one end in the axial direction opposite to the free end in the axial direction of the internal gear of the force increasing portion is fixed;
It is located between the fixed part and the thick part and on the free end side in the axial direction of the internal gear, the outer diameter is smaller than the outer diameter of the thick part, and more than the thick part. Also has a thin part with a thin thickness,
A tightening device, wherein a torque sensor is provided in the thin portion.

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