JP2000094355A - Torque wrench for clamping part in plastic region - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque wrench for a clamping part in a plastic region, capable of easily and reliably detecting whether or not a clamped bolt is clamped in a plastic region and capable of standardizing inspection. SOLUTION: A grip 12 is arranged on one end of a main body 14 of a torque wrench 10 for a clamping part in a plastic region, and a detachable socket 18 is provided on the other end through a gear 22 rotatable only in the clamping direction of a bolt 16a. An angle fixing member 20 for determining the start position of the rotation of the socket 18 is fixed to the gear 22. Torque to be applied to the socket 18 through the gear 22 is detected by a torque sensor 26, and the rotation angle of the socket 18 is detected by an encoder in an angle measuring gear box 24 and provided to a judging part in the main body 14. On the basis of the detected result, the judging part judges that the bolt 16a is clamping a work piece in a plastic region when the change of clamping torque in the specified angle change is not more than a specified value, and a plastic region judging LED 28d indicative of OK of the judgement is lighted up.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque wrench for a plastic region tightening portion, and more particularly to a plastic region tightening device capable of easily determining whether a tightening member enters a plastic region and tightens a work. It relates to improvement of a torque wrench for a part.

[0002]

2. Description of the Related Art Conventionally, fastening members such as screws and bolts have been used for fastening separated mechanical parts and the like. Screws and bolts are used in various fields because they generate a strong fastening force by an easy screwing operation. Usually, when a bolt or the like is tightened, there are a method called torque tightening and a method called plastic zone tightening. The torque tightening is a method of tightening a bolt and completing the tightening when the tightening torque during the operation exceeds a predetermined value. On the other hand, plastic region tightening is a method of continuing the tightening work of the bolt until the bolt is extended by the work tightening and reaches the plastic region,
Tightening can be performed more strongly than the torque tightening, and there is an advantage that loosening due to vibration or the like is unlikely to occur. This plastic region tightening is used for tightening head bolts, con-lot bolts, and the like of engines of automobiles and the like which are frequently subject to vibration.

[0003] When performing the plastic region tightening, a tightening device using a motor such as a nut runner is used. By the way, in a production line or the like, it is necessary to periodically inspect (sampling inspection) whether or not the plastic zone is sufficiently tightened in terms of manufacturing quality. Normally, when the bolt reaches the plastic region, the tightening torque does not increase thereafter even if the bolt is tightened. Utilizing this characteristic, the torque rise is increased by, for example, 50 × 9.8 Nm by turning a predetermined angle, for example, 30 °, from the point in time when the increase in torque is reduced or reduced.
If it was within, it was determined that the plastic zone was tightened. By performing such an inspection regularly, it is possible to maintain a fastening operation with stable quality.

Japanese Patent Application Laid-Open No. 7-40262 discloses that
A method is disclosed in which the rate of increase in torque with respect to the tightening angle of the bolt is calculated, and the change in the rate of increase is used to determine plastic region tightening. According to this method, it is possible to determine whether or not plastic region tightening has been performed at the time of bolt tightening.

[0005]

However, when an inspection for tightening the plastic region is performed, the torque that reaches the plastic region differs for each bolt. Further, the torque that reaches the plastic region also varies depending on the state of the screw hole (state of the nut) of the work to be fastened.
In other words, there is a problem that a stable determination cannot be easily made because the torque indicating the point in time when the plastic region is entered changes each time. For example, depending on the inspector, a predetermined angle (30 °)
, The reliability of the results was reduced, and it was difficult to standardize the judgment of the plastic zone closure. When calculating the rate of increase in torque with respect to the bolt tightening angle,
Since the change in the tightening torque is small after the bolt tightening is completed, it is not suitable for the determination after the bolt tightening. That is, although the determination at the time of bolt tightening can be performed, it is not suitable for a sampling inspection or the like. In addition, a large measuring device is required for the judgment, and the inspection cannot be easily performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is possible to reliably and easily detect whether or not a fastening member after completion of fastening is tightened in a plastic region, and to easily perform standardization of inspection. An object of the present invention is to provide a torque wrench for a plastic region tightening portion.

[0007]

In order to achieve the above object, a first aspect of the present invention is to provide a main body having an operation grip, and a tightening mechanism provided at an opposite end of the main body grip to tighten a work. A socket connectable to a member and rotatable and detachable, a gear interposed between the socket and the main body and capable of transmitting the rotation of the socket, and a member connected to the gear and defining a rotation angle reference of the socket. An angle fixing member capable of adjusting an interval between the socket and the socket; an angle detector for detecting the socket rotation angle; a torque detector for detecting a tightening torque of the socket with respect to the tightening member; It is determined that the fastening member is tightening the work in the plastic region when the change in the tightening torque is within the predetermined value within the predetermined angle change based on the detection results of the section and the torque detection section. Characterized in that it comprises a determining unit. According to this configuration, it is possible to reliably and easily detect whether or not the fastening member after the completion of the fastening is tightened in the plastic region from the torque fluctuation within the predetermined rotation angle. In addition, since the start timing of the torque fluctuation can be easily and stably specified by determining the rotation angle reference by the angle fixing member, the inspection can be standardized.

In order to achieve the above object, a second invention based on the first invention is characterized in that the determination section has a counter for recognizing the number of determinations. According to this configuration, even when a plurality of tightening members are present in the work and the plastic region tightening inspection is sequentially performed, the number of inspections is not erroneously recognized, and it is possible to prevent the omission of the inspection and improve the reliability of the determination. Can be.

According to a third aspect of the present invention, in the first or second aspect, the determining section outputs an interlock signal to a related device based on the determination result. It is characterized by. According to this configuration, when a defect occurs, the subsequent process can be stopped without fail, and the determination result can be used effectively and reliably.

In order to achieve the above object, a fourth aspect of the present invention is the invention according to any one of the first to third aspects, wherein the determination section includes a detection result of the angle detection section and the torque detection section, and a plastic region tightening. And an analog output section for outputting any of the determination results. According to this configuration, it is possible to easily perform the process control of the plastic region tightening operation,
Inspection can be standardized easily.

[0011] In order to achieve the above object, a fifth aspect of the present invention is the invention according to any of the first to fourth aspects, further comprising the step of determining whether or not the tightening member has reached a plastic range and is tightening the work. It is characterized by having switching means for switching between a judgment mode for judging and a tightening mode for tightening the tightening member to the plastic region. According to this configuration, it is possible to perform an inspection regarding the plastic region tightening with the same torque wrench at an arbitrary timing during the tightening operation of the tightening member, and a quick inspection operation can be easily performed. The nutrunner and the inspection device can be shared, and the process can be simplified easily.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention (hereinafter referred to as embodiments) will be described below with reference to the drawings.

FIG. 1 is a schematic perspective view of a torque wrench 10 (hereinafter simply referred to as a torque wrench) for a plastic region fastening portion according to the present invention. The torque wrench 10 includes an operation grip 12 held by a user and the grip 1
2 is disposed at one end, and a main body 14 in which a circuit board including a determination unit to be described later and a battery (for example, a dry battery) for driving the circuit are housed. For example, a bolt 16a
A socket 18 engageable with a head portion of the
Is constituted by an angle fixing member 20 and the like for specifying the starting position of rotation when rotating for tightening.

The socket 18 is provided with bolts 1 of various sizes.
6a, the grip 1
2 is detachably connected to a ratchet in a gear 22 formed at the opposite end. The main body 14 of the torque wrench 10
A ratchet mechanism that can transmit torque is provided at the tip of the
The socket 18 fits into this drive unit and transmits torque. A gear 22 provided outside the socket 18
Is rotatably provided with the ratchet as a core via a bearing. This gear 22 is composed of the main body 14 and the socket 18
The gear for detecting the rotation angle of the motor does not transmit the tightening torque. The gear 22 is connected to an angle measuring gear box 24 as an angle detecting unit, so that the rotation angle of the socket 18 can be directly detected. The detected rotation angle of the socket 18 is provided to a determination unit of the main body 14. The gear 22 is connected to the angle fixing member 20. The angle fixing member 20 has a holder 20a which can be engaged with a head portion of a bolt at the distal end similarly to the socket 18, and engages with a bolt 16b near (preferably adjacent) the bolt 16a with which the socket 18 is engaged. Combine. Therefore, by connecting the angle fixing member 20 to the bolt 16b other than the bolt 16a with which the socket 18 is engaged, the starting position of the rotation of the gear 22 can be determined. Note that the holder 20a is the main body 20 of the angle fixing member 20.
b (replaceable according to the shape of the bolt 16b to be connected), and the spring 20c
Can move up and down. Further, the main body 20
The arm 20d connecting the gear b and the gear 22 is slidable in the direction of arrow B. Therefore, the position of the holder 20a can be moved to an arbitrary position, and even when the height of the mounting position of the bolt 16a with which the socket 18 engages and the bolt 16b with which the holder 20a engages is different or the relative distance changes. Both the bolts 16a and 16b can be easily engaged with the socket 18 and the holder 20a.

The main body 14 is provided with a well-known torque sensor (torque detecting unit) 26 for measuring a tightening torque applied to the socket 18 by the gear 22, and measures the tightening torque in real time. Is provided to the determination unit.

A torque wrench 10 is provided on the surface of the box portion 14a for housing a battery or the like in the main body 14.
Power switch 28a, various displays (peak torque display,
A liquid crystal display unit 28b for performing a tightening angle display, an alarm display, a counter display, etc., a reset button (clear display at the end of inspection, clear stored data, clear an interlock signal described later, etc.), and a mode switching button (described later). An operation button group 28c such as a switching between a tightening mode and a determination mode), a set value change button (change of an inspection condition or the like), a plastic region determination LED 28d (for example, OK is green and NG is red) are arranged. . An interlock output cable 30a and an analog output cable 30b, which will be described later, protrude from the side surface of the main body 14. Although FIG. 1 shows an example in which each cable is pulled out from the side surface, the position where the cable is pulled out is arbitrary, and the cable may be unified by using a connector or the like, or the cable may be connected by a connector only when data is required. You may make it connect. In addition, wireless transmission of data may be performed.

The torque wrench 10 configured as described above
The usage of is explained. First. The plastic region tightening determination will be described with reference to FIG. As shown on the left side of FIG. 2, usually, in a manufacturing process of an automobile engine or the like, a bolt 16a is continuously tightened by a nut runner or the like. This work is based on the preset snag torque Tg.
(For example, 350 × 9.8 Nm) and a plastic region tightening (for example, 1050 × 9.8 Nm ± 400 × 9.8 N) while being tightened at a predetermined angle (for example, 180 ° ± 10 °).
m) has been completed.

In the case of the present embodiment, for the work arbitrarily extracted from the work tightened in the plastic region by the nut runner, the plastic region tightening judgment is performed by the torque wrench 10 shown in FIG. First, the holder 20a of the angle fixing member 20 is fixed to the bolt 16 adjacent to the bolt 16a to be determined.
b, and then the socket 18 is mounted on the bolt 16a to be determined. At this time, as described above, the relative position of the holder 20a with respect to the socket 18 can be arbitrarily adjusted, so that both can be easily mounted. In this state, the user grips the grip 12 of the main body 14 and rotates the main body 14 in the tightening direction. At this time, the angle fixing member 20
The gear 22 which starts rotating relative to the main body 14 starts rotating. This rotation is transmitted to the angle measurement gear box 24 via the gear 22, and the rotation angle is read by an internal encoder. At the same time, torque reading by the torque sensor 26 is performed. As shown on the right side of FIG. 2, the bolt 16 already sufficiently tightened is completed.
In the case of a, the torque increases simultaneously with the rotation. Note that, in the case of the present embodiment, it is assumed that reading of the rotation angle by the encoder is started at a point in time when the torque sensor 26 exceeds a preset trigger torque Ta.

The determination section inside the main body 14 sets a torque when the trigger torque Ta is reached and further rotated by a predetermined neglect angle θn (for example, 2 to 3 °) as a start torque Ts. By rotating the bolt 16a by the amount of the neglect angle θn prior to the start of the determination, it is possible to absorb the variation in the plastic deformation start timing of the bolt 16a or the bolt 16a which varies for each work. The judging unit recognizes the maximum torque until it is further rotated by a predetermined angle θr (for example, 30 °) as the peak torque Tp. The determination unit calculates a determination amount Th = Tp−Ts from the recognized Ts and Tp, and when the determination amount Th ≦ the specified value (for example, 50 × 9.8 Nm), the plastic region tightening is performed well. Then, the OK (green) side of the plastic region determination LED 28d formed on the main body 14 is turned on (see FIG. 1). On the other hand, when the determination amount Th> predetermined value, that is, since the bolt is seized or the nut runner is out of order, it is determined that the complete plastic region tightening has not been performed, and the NG of the plastic region determination LED 28d is determined.
Turn on the (red) side. At the same time, an interlock signal is output to another device via the interlock output cable 30a. In addition, if necessary, OK judgment and NG
The data relating the rotation angle and the torque at the time of determination and the determination result are output to a storage device (not shown) from the analog output cable 30b.

When the NG determination is made, the work that has been closed in the plastic region is checked between the previous determination and the present determination. In general, a plurality of head bolts and the like of an automobile engine are arranged at equal intervals for one work, so that the angle fixing member 20 can be easily fixed. In addition, since the torque wrench 10 of the present embodiment displays a counter indicating the number of determinations, even when a plurality of bolts are present in the work and the inspection (judgment) of the plastic region tightening is sequentially performed, erroneous recognition of the number of inspections is performed. In addition, it is possible to prevent the omission of the inspection and improve the reliability of the determination.

As described above, by determining the reference of the rotation angle by the angle fixing member 20, the start timing of the torque fluctuation can be easily and stably specified. Further, it is possible to reliably and easily detect whether or not the fastening member after the completion of the fastening is tightened in the plastic region from the torque fluctuation within the predetermined rotation angle. Therefore, the inspection staff can standardize the inspection without error.

FIG. 3 is a conceptual diagram of a system in a plastic zone tightening step including an inspection using the torque wrench 10 described above. The conveyor 32 that moves the workpiece detects the dog 36 disposed on the conveyor belt by the limit switch (LS) 34 for detecting a fixed position, provides the detection signal to the conveyor control panel 38, and controls the conveyor motor 40. Thus, the intermittent operation is performed at a predetermined interval. The OK and NG signals including the interlock signal output from the torque wrench 10 are provided to the conveyor control panel 38 via the nut runner control panel 44 of the nut runner 42, and stop control in the event of an abnormality or the like is performed. .

FIG. 4 shows a timing chart of each signal. The conveyor rotation signal output from the conveyor control panel 38 is normally output as a stop and start signal based on the conveyor fixed position signal from the limit switch 34. NG output by the torque wrench 10
An interlock signal based on the signal is supplied to the nut runner control panel 44, and a fastening abnormality signal is transmitted to the conveyor control panel 38.
Is also output, the conveyor rotation signal stops. When the conveyor control panel 38 recognizes the interlock signal, the operation is continued to the home position based on the detection of the dog 36, and thereafter, stops at the home position. On the other hand, restart after the conveyor rotation signal is stopped, in normal inspection operation,
It is confirmed that the plastic region tightening determination for each work to be inspected has been completed for the number of tightenings (for example, the liquid crystal display unit 28).
When the counter shown in b has confirmed the end of the inspection by counting a predetermined number of OK signals), when the NG signal is detected, and when the quality check of the workpiece from the previous determination to the present determination is completed, the tightening confirmation OK signal is output. Is output, and when the abnormal tightening signal is withdrawn (when the interlock release signal is output from the torque wrench 10), the restart is performed.

As described above, by outputting the interlock signal from the torque wrench 10, even if a failure occurs in the tightening of the plastic region, it is possible to reliably stop the subsequent process and prevent the outflow of the defective product. Thus, the determination result can be used effectively and reliably. Further, as described above, if the rotation angle and the detected torque used for the determination are output from the analog output cable 30b to the storage device side, it can be used as data for failure analysis and process analysis.

The system shown in FIG. 3 shows an example in which the plastic region tightening operation is continuously performed by the nut runner 42 and the sampling inspection (determination) is performed by the torque wrench 10 at a predetermined timing. In a small-scale assembly line or the like in which the nut runner 42 cannot be introduced, the plastic region tightening operation and the determination operation can be performed only with the torque wrench 10 of the present embodiment. First, when performing the plastic region tightening operation, the mode switching button in the operation button group 28c on the main body 14 is switched to the tightening mode, and the plastic region tightening operation as illustrated on the left side of FIG. 2 is performed. Further, at an arbitrary timing, the mode switching button is operated to switch to the determination mode, and the plastic region tightening determination operation shown in the right side of FIG. 2 is performed. As described above, it is possible to perform the inspection (determination) regarding the plastic region tightening at an arbitrary timing during the tightening operation of the bolt 16a, and it is possible to easily perform the quick inspection operation. Also,
The nut runner and the inspection (judgment) device can be shared, and the process can be simplified, the equipment cost can be reduced, and the like.

In the present embodiment, the various torques and rotation angles that have been set are arbitrary, and the setting can be changed by the set value change button of the operation button group 28c. It is preferable to arbitrarily select the type and shape of the bolt and the design specifications of the work.

[0027]

According to the present invention, it is possible to reliably and easily detect whether or not the fastening member after the completion of the fastening is tightened in the plastic region from the torque fluctuation within a predetermined rotation angle. In addition, since the start timing of the torque fluctuation can be easily and stably specified by determining the rotation angle reference by the angle fixing member, the inspection can be standardized.

[Brief description of the drawings]

FIG. 1 is a conceptual perspective view illustrating a configuration of a torque wrench for a plastic region fastening portion according to an embodiment of the present invention.

FIG. 2 illustrates a relationship between a torque variation and a rotation angle at the time of quality check (judgment) when the torque wrench for a plastic region tightening portion according to the embodiment of the present invention is used and at the time of performing plastic region tightening by a nut runner. FIG.

FIG. 3 is an explanatory diagram illustrating a layout of a plastic region tightening process when performing interlock control using the torque wrench for a plastic region tightening portion according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a timing chart of signals output from each device in the layout of FIG. 3;

[Explanation of symbols]

Reference Signs List 10 Torque wrench for plastic region tightening part, 12 grip, 14 body, 16a bolt (tightening member), 18 socket, 20 angle fixing member, 20a holder, 20b
Body, 20c spring, 20d arm, 22
Gear, 24 angle measurement gear box, 26 torque sensor, 28a power switch, 28b liquid crystal display, 28
c operation button group, 28d LED for plastic region judgment, 30
a Interlock output cable, 30b Analog output cable.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshitaka Kamikubo 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Kenji 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation ( 72) Inventor Mitsuaki Morita 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Shozo Aikawa 1-16-5 Omori Nishi, Ota-ku, Tokyo Co., Ltd. Nobuyoshi Kobayashi F-term (reference) 3C038 AA03 CA06 CA07 CC08 EA02 1-16-5 Omorinishi, Ota-ku, Tokyo

Claims (5)

[Claims] A main body having an operation grip; a socket provided at an opposite end of the grip of the main body, connectable to a tightening member for tightening a work, and rotatable and detachable; and between the socket and the main body. A gear interposed between the gears and capable of transmitting the rotation of the socket; a member connected to the gear and defining a reference for the rotation angle of the socket; an angle fixing member capable of adjusting a space between the socket and the socket; An angle detector for detecting a torque of the socket with respect to the tightening member; a torque detector for detecting a tightening torque of the socket; and a tightening torque within a predetermined angle change based on a detection result of the angle detector and the torque detector. And a determination unit for determining that the fastening member is tightening the work in the plastic region when the change in the torque is within a predetermined value. Ji. 2. The torque wrench according to claim 1, wherein the determination unit includes a counter that recognizes the number of determinations. 3. The torque wrench according to claim 1, wherein the determination unit outputs an interlock signal to a related device based on a determination result. Torque Wrench. 4. The torque wrench according to claim 1, wherein the determination unit outputs one of a detection result of the angle detection unit and the torque detection unit and a determination result of plastic region tightening. A torque wrench for a plastic region tightening portion, comprising: an analog output portion. 5. The torque wrench according to claim 1, further comprising: a determination mode for determining whether or not the tightening member has reached a plastic region to tighten the work. A torque wrench for a plastic region tightening portion, comprising: switching means for switching a tightening mode for tightening the plastic region to a plastic region.