JP3005466U - Nut runner - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a nut runner that can accurately detect tightening torque. [Structure] The nut runner body 1 is fixedly installed on a fixed body 8 via a casing 5. An internal gear 13 is rotatably provided in the casing 5. A sun gear is formed on the outer surface of the output rotary shaft 3 of the nut runner body 1, the planet gear 11 is interposed between the sun gear 4 and the internal gear 13, and the shaft 12 of the planet gear 11 is supported by the spindle 10. Transducer 1 in casing 5
5, the front and rear ends of the transducer 15 are connected to the casing and the internal gear 13. The strain gauge 18 is attached to the outer wall of the transducer 15.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a nut runner used for bolt tightening work, and more particularly to a nut runner capable of detecting that a predetermined tightening torque has been reached.

[0002]

[Prior art]

 Conventionally, a nut runner that automatically stops when a predetermined tightening torque is reached has already been developed. One example is shown in FIG. In the figure, 30 is a nut runner main body, 31 is a transducer, 32 is a spindle, 33 is a fixed frame, and 34 is a strain gauge. Since the nut runner main body 30 is attached to the fixed frame 33 through the transducer 31, the rotational reaction force due to the tightening work acts on the transducer 31, and the transducer 31 receives a torsion of the same magnitude as the tightening torque. And transform. Then, this deformation is detected by the strain gauge 34, the tightening torque is calculated from this detected value, and when the predetermined tightening torque is reached, the nut runner is automatically stopped.

[0003]

[Problems to be solved by the device]

 However, since the above-mentioned conventional type is a type in which the nut runner main body is supported by the transducer, all the force applied to the nut runner main body acts on the transducer. Therefore, it is affected not only by the reaction force at the time of rotation tightening but also by all other forces applied to the nut runner. For example, when the nut runner is used horizontally, the weight of the nut runner is applied to the transducer, and therefore the force of its own weight is applied to the deformation of the transducer. In this type of conventional device, a force other than the reaction force of the tightening torque acts on the transducer, and the strain gauge detects the deformation caused by these forces.Therefore, only the tightening torque is accurately measured. However, the actual tightening torque varies and the accuracy of tightening work is reduced.

In view of the above, the present invention is to provide a nut runner that improves the detection accuracy of the tightening torque by allowing only the reaction force of the tightening torque to act on the transducer. is there.

[0005]

[Means for Solving the Problems]

 The technical means of the nut runner of the present invention includes a nut runner main body, a spindle connected to the output rotation shaft of the nut runner main body through a planetary gear type speed reducing mechanism, and an outer side of the spindle. It consists of a casing fixedly supported by a fixed body, a transducer installed in the casing, and a strain gauge attached to the transducer.The internal gear of the planetary gear reduction mechanism is separate from the casing. It is rotatably provided with respect to the casing, and both ends of the transducer are connected to the casing and the internal gear, respectively.

The front end of the transducer may be splined to the inner surface of the casing, and the rear end of the transducer may be splined to the front end of the internal gear.

Further, it is possible to form a sun gear on the outer surface of the output rotary shaft of the nut runner main body and to support the planet gear shaft meshing with the sun gear and the internal gear by the spindle.

[0008]

[Action]

 In the nut runner of the present invention, the output rotary shaft of the nut runner main body and the spindle are connected via the planetary gear type speed reducing mechanism, so that the rotation of the output rotary shaft is decelerated and transmitted to the spindle. Then, attach an appropriate tool to the tip of this spindle and perform screw tightening work. Further, since the nut runner body is fixedly supported by the fixed body through the casing, the force acting on the nut runner body is supported by the casing including its own weight. Therefore, no force for supporting the nut runner body acts on the transducer provided inside the casing.

Further, the internal gear of the planetary gear type speed reducing mechanism is separate from the casing and has a rotatable relationship with the casing. A transducer is interposed between the two, and both ends of the transducer are connected to the internal gear and the casing. That is, the internal gear is fixedly supported by the transducer, and the rotational reaction force applied to the internal gear during nut runner operation is supported by the transducer. As a result, the transducer naturally undergoes torsional deformation due to the rotational reaction force. Since this torsional deformation amount is proportional to the magnitude of the reaction force, the tightening torque of the nut runner can be obtained by detecting the deformation amount with a strain gauge.

[0010]

【Example】

 An embodiment of the nut runner of the present invention will be described with reference to the drawings. 1 is a nut runner main body, 2 is its casing, and 3 is an output rotary shaft. Currently, as the nut runner, an air type and an electric type are mainly used, but the type is not limited in the present invention. Further, teeth are formed on the outer surface of the output rotary shaft 3 to form a sun gear 4.

Reference numeral 5 denotes a common casing for the speed reducing unit 6 and the measuring unit 7, which is integrally connected and fixed to the front end of the main body casing 2. Further, the front end of the casing 5 is fixed to a fixed body 8 such as a nut runner mounting member. Reference numeral 10 is a spindle, and the output rotation shaft 3 is rotatably fitted in the rear end thereof. Reference numeral 11 is a planet gear, and its shaft 12 is supported by the rear portion of the spindle 10. Reference numeral 13 denotes an internal gear, which is rotatably supported on the inner surface of the casing 5 via a bearing 14. The sun gear 4, the planet gears 11, and the internal gear 13 are meshed with each other to form a speed reduction unit 6 of a planetary gear type speed reduction mechanism.

Reference numeral 15 denotes a transducer, which has a cylindrical shape and is loosely fitted to the outside of the spindle 10. The rear end of the transducer 15 is splined 16 with the front end of the internal gear 13, and the front end of the transducer 15 is splined 17 with the inner surface of the casing 5. Further, a strain gauge 18 is attached to the outer wall of the transducer 15, and the strain gauge 18 is signal-connected to the signal processing unit 19. The transducer 15, the strain gauge 18, and the signal processing unit 19 constitute a tightening torque measuring / controlling device 20.

Next, the operation of the apparatus of the above embodiment will be described. When the nut runner body 1 is started, the output rotary shaft 3 rotates. This rotation is decelerated by the planetary gear type speed reduction mechanism and transmitted to the spindle 10. A tool is attached to the tip of the spindle 10 to perform bolt tightening work. During this tightening work, a rotational reaction force acts on the internal gear 13. Since the internal gear 13 is separate from the casing 5 and is rotatably supported, it tries to rotate by this reaction force.

This rotating force of the internal gear 13 is transmitted to the transducer 15 connected to the front end portion of the internal gear 13 and tries to rotate the transducer 15 in an interlocking manner. However, the front end of the transducer 15 is prevented from rotating by the connection 17 with the casing 5. Therefore, the transducer 15 is twisted and deformed corresponding to the rotational force. The twist deformation of the transducer 15 is always detected by the strain gauge 18, and when the predetermined deformation amount is reached, that is, when the predetermined tightening torque is reached, the nut runner body 1 is automatically moved. To stop.

The transducer 15 is separate from the casing 5, and is completely separated from the casing 15 except that it is connected by a spline coupling 17. On the other hand, the casing 5 is fixed to the fixed body 8, and the nut runner main body 1 is fixedly supported by the casing 5. Therefore, no force other than the rotational reaction force acts on the transducer 15 in the casing 5, and the transducer 15 is not affected by other external force acting on the nut runner, such as gravity of the nut runner body 1. Absent. As a result, accurate torque detection is always possible.

It should be noted that the present invention is not limited to the above-mentioned embodiment, and can be freely modified and implemented within the scope of the claims for utility model registration. In particular, the type of nutrunner body, the detailed shape of the planetary gear type speed reducer, and the shape of the transducer are free.

[0017]

[Effect of device]

 The nut runner of the present invention is fixedly supported by the casing, and no force related to the support of the nut runner acts on the transducer contained in the casing separately from the casing. In other words, since only the rotational reaction force that accompanies the screw tightening operation acts on the transducer, the torsional deformation of the transducer accurately corresponds to the rotational reactional force, and the torsional deformation is detected by the strain gauge to accurately check the tightening torque. You can ask. Furthermore, the nut runner of the present invention has a structure in which the internal gear of the planetary gear type speed reducer mechanism is provided separately from the casing, rotatably provided in the casing, and coupled to the end of the transducer. The advantages are that the structure is simple, there are no malfunctions, it is easy to manufacture, it can be provided at low cost, and there are few failures.

According to the second aspect, since both ends of the transducer are spline-coupled, only the rotational reaction force can be accurately transmitted to the transducer with a simple structure, and the torque measurement can be performed with high accuracy. .

According to the third aspect of the present invention, the planetary gear type speed reducing mechanism can be simply constructed, and the structure of the entire Runner can be simplified and downsized.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of an embodiment of a nut runner of the present invention.

FIG. 2 is a sectional view taken along line AA.

FIG. 3 is a side view of a conventional nut runner.

[Explanation of symbols]

 1 Nutrunner Main Body 2 Casing 3 Output Rotating Shaft 4 Sun Gear 5 Casing 6 Reduction Unit 7 Measuring Unit 8 Fixed Body 10 Spindle 11 Planet Gear 12 Shaft 13 Internal Gear 14 Bearing 15 Transducer 16, 17 Spline Coupling 18 Strain Meter 19 Signal Processing Unit 20 Tightening torque measurement / control device

Claims (3)

[Scope of utility model registration request] 1. A nut runner main body, a spindle connected to an output rotary shaft of the nut runner main body via a planetary gear type speed reduction mechanism, and an outer side of the spindle is surrounded to fix and support the nut runner main body to a fixed body. The internal gear of the planetary gear type speed reducing mechanism is a separate body from the casing and is rotatable with respect to the casing, the casing, a transducer provided in the casing, and a strain gauge attached to the transducer. A nut runner is provided, and both ends of the transducer are connected to the casing and the internal gear, respectively. 2. The nut runner according to claim 1, wherein a front end of the transducer is splined to an inner surface of the casing, and a rear end of the transducer is splined to a front end of the internal gear. 3. The nut runner according to claim 1, wherein a sun gear is formed on the outer surface of the output rotary shaft of the nut runner main body, and the planet gear shaft meshing with the sun gear and the internal gear is supported by the spindle.