JPS61279441A - Bolt force fitting and fastening device - Google Patents

Abstract

PURPOSE:To enable bolts to be force fitted and fastened continuously only with a nut runner, by utilizing the rotary operation of the nut runner to force fit connecting rod body of the bolt, i.e. a member to be force fitted into a bolt inserting hole. CONSTITUTION:A first torque setter 8 sets a first predetermined torque value produced in a nut runner 1 in a bolt force fitting process. A second torque setter 9 sets a second torque value larger than the first one. A timer 19 sets force fitting time needed from starting the operation of nut runner 1 to the completion of force fitting the bolt. A force fitting judging section 21 judges the proper force fitting condition of the bolt when the rotational torque of the nut runner 1 detected by a torque detector within the forcing time set by the timer 19 exceeds the first torque value set by the first torque setter 8 and does not reach the second torque value set by the second torque setter 9.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a bolt having a shaft portion formed with a press-fitting groove and a nut screwed onto the bolt, which are rotated relative to each other. The present invention relates to a press-fitting and tightening device that continuously press-fits and tightens a press-fitted member.

(Prior Art) Generally, the big end of a connecting rod that connects an engine piston and crankshaft is divided into a connecting rod body and a cap, and these two parts are usually manufactured in separate processes. After being manufactured, they are assembled together by sandwiching the crankshaft in the connecting rod cap assembly process. That is, in the above-mentioned connecting rod cap assembly process, a stud bolt having serrations on its shaft portion is press-fitted into a bolt insertion hole of a connecting rod body using the serrations, and then a nut is screwed into the threaded portion of the bolt via the cap. This allows the connecting rod body and the cap to be integrated.

By the way, when assembling a cap to the connecting rod body by press-fitting a bolt into the connecting-rod body and screwing a nut onto the press-fitted bolt, conventionally the bolt was press-fitted into the connecting-rod body and then tightened with the nut. This is carried out at separate stations, and after the bolt is press-fitted by, for example, a press-fitting press at the bolt press-fitting station, the bolt is tightened with a nut using a nut runner at the station.

(Problems to be Solved by the Invention) However, in the above conventional method, the press-fitting and tightening of the bolts are performed at separate stations, so the press-fitting brace IN
Both the d3 and nut runner blades are required, and the work involved in the connecting rod cap assembly process is troublesome.

The present invention has been made in view of the above, and its object is to utilize the rotational movement of the nut runner that screws the nut and bolt together to tighten the bolt body, etc. of the bolt.
By press-fitting the press-fitted member into the bolt insertion hole, a press-fitting press or the like for press-fitting the bolts is not necessary, and the bolts can be press-fitted and subsequently tightened continuously using only the nut runner. There is a particular thing.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention is as described above, in which a bolt having serrations on the shaft portion and a nut screwed onto the bolt are connected by a nut runner. First, a torque detector is provided to detect the rotational torque of the nut runner as a bolt press-fitting tightening device which press-fits a bolt into a bolt insertion hole of a press-fitted member and then tightens the bolt by relatively rotating the bolt. Further, a first torque setting device sets a predetermined first torque value generated in the nut runner during the bolt press-fitting process, and a first torque value generated at the nut runner during the tightening process after the bolt is press-fitted. a second torque setting device that sets a second torque value that is larger than the first torque value; a timer that sets the press-fitting time required from the start of operation of the nut runner to the end of press-fitting the bolt; , when the rotational torque of the nut runner detected by the torque detector exceeds the first torque value set by the first torque setting device and does not reach the second torque value set by the second torque setting device. A press-fitting control means is provided having a press-fitting determination section that determines the proper press-fitting state of the bolt. Furthermore, a tightening control means is provided for stopping tightening by the nut runner when the rotational torque of the nut runner detected by the torque detector reaches a set value during the tightening process of the bolt.

(Function) With the above configuration, in the present invention, when the nut is screwed into the pin 1 inserted into the bolt insertion hole of the press-fitted member and the nut runner is operated in this state, the bolt and the nut are rotated relative to each other. With this rotation, the bolt is first press-fitted into the bolt insertion hole of the press-fitted member by the serrations of its shaft portion, and after this press-fitting process is completed, the bolt is subsequently tightened with a nut. Further, at the same time as the nut runner starts operating, a timer starts counting the press-fitting time. The rotational torque of the nut runner is detected by a torque detector during the press-fitting process and tightening process of the bolt, and the rotational torque of the nut runner is detected by a torque detector, and the rotational torque is set by a first torque setting device and a second torque setting device, respectively. Then, the relationship between the time when the second torque value is reached and the end of the press-fitting time by the timer, that is, the time when the bolt transitions from the press-fitting process to the tightening process, is determined, and the rotational torque is determined to be the end of the press-fitting time by the timer. If the first torque value is reached before and the second torque value is reached after the end of the press-fitting time, it is determined that the bolt has been properly press-fitted into the bolt through hole according to the standard. In other words, if the rotational torque has not yet reached the first torque value even though the press-fitting time indicated by the timer has elapsed, it can be assumed that the press-fitting pressure of the bolt is insufficient. Conversely, if the rotational torque reaches the second torque value before the end of the operating time, it can be assumed that the press-fitting pressure of Pole 1- is excessive, and in either case, the press-fitting condition of the bolt is determined to be inappropriate. Ru.

After this press-fitting determination, in the process of tightening the nut, when the detected rotational torque of the nut runner reaches a set value, the tightening by the nut runner is stopped. The above operations complete the press-fitting of the bolt and subsequent tightening. Therefore, the bolts are press-fitted and tightened continuously by such rotational operation of the nut runner.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 schematically shows the overall configuration of a bolt press-fitting and tightening device A according to an embodiment of the present invention. As shown in Fig. 4, the press-fitting tightening device △ is connected to each of the connecting rod body W and the cap W', which are press-fitted members constituting an engine connecting rod, and the corresponding port I-insertion hole W+ + W' +. A stud bolt B that is inserted into both from the connecting rod body W side and has a serration BI near the head of the shaft part, and a nut t-N that is screwed onto each bolt B from the cap W' side are relatively rotated. , due to its rotation, the bolt B is inserted into the bolt insertion hole W of the rod body W with its serration B1.
It is used to assemble the cap W' to the connecting rod body W by pressing it into the connecting rod body W and then tightening it with the nut N.

The press-fitting and tightening device A is provided with a nut runner 1 for relatively rotating each bolt B and a nut N screwed onto the bolt B. The nut runner 1 includes a head portion 2 having a fitting hole 2a into which the head portion of a bolt B or a nut N can be fitted, and a DC motor 4 that rotationally drives the head portion 2 via a reduction gear mechanism 3. The above motor 4 (
The nut runner 1) is started to operate in response to a start i3@ from the nut runner operation start signal generating circuit 5. In addition, a shaft portion between the head portion 2 and the reduction gear 1m structure 3 is provided with a torque that detects the rotational torque T of the nut runner 1 when the bolt B is press-fitted and tightened by the nut runner 1, and generates a voltage corresponding to the rotational torque T. A torque transducer 6 is installed as a detector.

In addition, a pulse transducer 7 (angle encoder) that detects the number of rotations of the motor 4 and generates a pulse signal in accordance with the rotation speed of the motor 4 is mounted on the shaft between the reduction gear mechanism 3 and the motor 4.
is installed.

In addition, 8 is a first torque setting device that sets a predetermined first torque value 1''I that is generated in the nut runner 1 during the tightening process of the bolt B, and 9 is a torque setting device that is generated in the nut runner 1 during the tightening process after the bolt B is press-fitted. a second torque setting device that sets a second torque 5n T2 that is larger than the first torque value T1 that is generated;
10 occurs during the same tightening process. The second torque value T2
29 is a fourth torque setting device for setting a third torque value lower 3 which is larger than the final tightening torque value T4 and smaller than the final tightening torque value T4; The torque values T+ to T4 set by these torque setting devices 8 to 10 and 29 are based on the change in rotational torque with respect to the elapsed time from the start of operation of the nut runner 1, which has been determined in advance through experiments, etc., as shown in FIG. Determined based on reference characteristics.

Further, 11 indicates an O when the rotational torque T of the nut runner 1 detected by the torque transducer 6 is larger than the first torque value TI set by the first torque setting device 8.
The first comparator 12 that outputs the N signal outputs a sharpening ON signal when the rotational torque T of the nut runner 1 is greater than the second torque value lower 2 set by the second torque setting device 9. The outputs of these comparators 11 and 12 are turned on by the first logic circuit 13, respectively.
The signal is input to the same logic circuit 13 via first and second analog switch circuits 14 and 15 which are turned off. Further, reference numeral 16 indicates a third torque value T at which the rotational torque T of the nut runner 1 is set by the third torque setting device 10.
3, the output of the comparator 16 is connected to a second logic circuit 17 that operates in conjunction with the first logic circuit 13. The signal is input to the same logic circuit 17 via an analog switch circuit 18 of M3, which is ON/OFF controlled by .

Furthermore, when the rotational torque of the nut runner 1 reaches the fourth torque value T4, the 30 outputs an ON signal to the second logic circuit 17.
This output is the fifth comparator that outputs to the nut runner 1.
This is a signal to stop the operation. Note that the fourth torque setting device 29. The comparator 30 and the 20th switch circuit 17 constitute a tightening control means 2B. The logic circuits 13 and 17 operate upon receiving the operation start signal output from the nut runner operation start signal generating circuit 5.

On the other hand, 19 is the press-fitting time j, such as 10 seconds, required from the start of operation of the nut runner 1 to the end of press-fitting the bolt B.
+, that is, a press-fitting timer that sets the time required for the normal increase process of the bolt B, and the timer 19 receives the start signal from the first logic circuit 13 and sets the press-fitting time t10.
It starts counting the light, and when it counts up, outputs the signal to the logic circuit 13. Further, 20 is a cycle timer for setting a cycle time t2 required from the start of operation of the nut runner 1 to the end of press-fitting and tightening of the bolt B, and the timer 20 receives a start signal from the second logic circuit 17. It starts counting the cycle time t2, and when it counts up, outputs the signal to the logic circuit 17. Then, the first logic circuit 13 causes the first torque setter 8 to set the rotational torque T of the nut runner 1 detected by the torque transducer 6 within the press-fitting time fl determined by the press-fitting timer 19. Press-fit determination in which a state in which the bolt B exceeds the first torque value T1 and does not reach the second torque value T2 set by the second torque setting device 9 is determined to be a proper press-fit state of the bolt B into the bolt insertion hole W+. A section 21 is configured. Further, a press-fitting control means 22 for controlling the press-fitting of the bolt B is constituted by the press-fitting determining section 21, the first and second torque setters 8.9, and one press-fitting timer.

Furthermore, 23 is a pulse counter that counts the number of pulses of the pulse signal outputted from the pulse transducer 7 to detect the rotation angle of the nut runner 1.
When the rotational torque T2 reaches the pulse gate ON signal from the first logic circuit 13, pulse counting is started, and when the rotational torque T reaches the third torque T3, the second
Upon receiving the pulse gate OFF signal from the logic circuit 17, the pulse count is stopped, and the rotational torque T becomes the second
d T (=
fl and II are controlled so as to detect the rotation angle dθ of the nut runner 1 during the period when the rotation angle dθ changes by Tt −T2 ). 24 is a torque rate dT at which the rotational torque lower reaches the torque value lower 2 to T3 based on the output of the pulse counter 23.
The torque rate dT/dθ calculated by the calculation circuit 24 is the reference torque rate set by the torque rate setter 26 in the fourth comparator 25. If the torque rate dT/dθ is within the reference torque rate range, the comparator 25 outputs an ON signal. 27 is the comparator 2
A fourth analog switch circuit operates in response to the ON signal of No. 5, and its output is input to the second logic circuit 17, and the actual torque rate dT/dθ is within the reference torque rate range. When the bolt B is properly tightened by the nut runner 1, the torque rate d T
If /dθ exceeds the reference torque rate range, it is determined that the Bordeaux 8 is improperly tightened.

Next, the operation of the bolt press-fitting and tightening device A in the above embodiment will be explained along the operating procedure shown in FIG.

First, in step SI, the corresponding bolt insertion holes W+ + W' of the connecting rod body W and the cap W' are
+ Stud bolts B are inserted into both sides from the Hun rod body W side, and nuts N are screwed into each of the inserted stud bolts B from the cap W' side, and then the nuts l-N are inserted into a predetermined jig. The nut runner 1 is activated by a start signal from the nut runner operation start signal generation circuit 5 in a state where the bolt B is prevented from rotating and the fitting hole 2a of the head portion 2 of the nut runner 1 is fitted into the head portion of the bolt B. Press-fitting and tightening of bolt B is started. Further, in step S2, both logic circuits '13.17
operates, and the press-fit and cycle timer 19.
20 is not counted, and the first analog switch circuit 14 is kept in the ON state by the operation of the first logic circuit 13. Next, the process proceeds to step S3, where the rotational torque T generated in conjunction with the operation of the nut runner 1 is
is the first torque value T set by the first torque setting device 8
1 and whether an ON signal was output from the first comparator 11), and if the determination is NO, the process advances to step S4, where it is determined whether the press-fit timer 19 has counted up or not. It will be judged. If this determination is NO, the process returns to step $3, but if it is YES, that is, even after the predetermined press-fitting time t1 has elapsed since the start of operation of the nut runner 1, the nut runner 10 rotation torque is still below the first torque value in the press-fitting process. If T+ has not been reached, it is assumed that the press-fitting pressure of the bolt B into the bolt insertion hole W1 is insufficient, and the process proceeds to step S16 to check the incorrect press-fitted rNGJ.
(No Good> is determined.

If the determination in step S3 is YES, the process proceeds to step S5, where the first analog switch circuit 14 is turned off by the operation of the first logic circuit 13, and the second analog switch circuit 15 is turned on. In this state, it is determined whether or not one of the press-fit timers has counted up. If this determination is No, the process advances to step S6, and the rotational torque T of the nut runner 1 is set to the second level.
(Whether or not there is an ON signal from the second comparator 12)
is determined. If this determination is No, step S5
Returning to , if YES, that is, before the predetermined press-fitting time t1 elapses, the rotational torque T of the nut runner 1 reaches the second torque value T2 that should originally be generated during the tightening process to the pole 1. It is assumed that the press-fitting pressure of the bolt B into the bolt insertion hole WI is excessive, and the process proceeds to step S+6, where it is determined that the press-fitting is inappropriate rNGJ.

Furthermore, if the determination in step S5 is YES due to the count up of the press-fit timer 19, step S7
After the second analog switch circuit 15 is turned off by the operation of the first logic circuit 13 and the third analog switch circuit 18 is turned on by the operation of the second logic circuit 17, the nut runner is turned on. It is determined whether or not the rotational torque T of No. 1 has reached the second torque value T2. If this determination is NO, step Sa
Then, it is determined whether or not the cycle timer 20 has counted up. If this determination is NO, the process returns to step S7, but if it is YES, that is, the rotational torque T of the nut runner 1 reaches the second torque value T2 even though the bolt B has originally been press-fitted and tightened. If not, the process proceeds to step S+s, where rNG and J are determined.

Then, when the determination in step S7 is YES (when the rotational torque of the nut runner 1 has reached the second torque value T2), the pulse counter 2 is
The pulse gate 3 is turned on, and the pulse counter 23 counts the number of signal pulses from the pulse transducer 7.

Thereafter, the process moves to step S+t+, where the rotational torque T of the nut runner 1 is set by the third torque setting device 10.
The third comparator 1 determines whether the torque lfi T 3 has been reached or not.
If the determination is No, the process advances to step Sn, where it is determined whether the cycle timer 20 has counted up.

When this determination is N or O, the process returns to step Sre, but when it is YES, that is, when it is considered that the press-fitting and tightening of the bolt B has been completed, the rotational torque of the nut runner 1 is lower than the third torque value T3. If this has not been reached, the process moves to step S16, where it is determined that rNGJ has occurred.

When the determination in step Sha is YES, the process moves to step S12, the pulse gate for the pulse counter 23 is turned off, the counting of the number of signal pulses by the pulse counter 23 is completed, and the pulse counter 23 rotates the nut runner 1. An angle dθ is detected.

Next, the process moves to step S+3, and in the numbing circuit 24, the nut runner 10 rotation torque T is changed to the second torque till.
The torque value is changed from T2 to T based on the torque change value dT=Ts-72 when increasing from T2 to the third torque value lower 3 and the rotation angle dθ of the nut runner 1 required during that time.
The torque rate dT/dθ between 3 and 3 is calculated. After that, the process proceeds to step S14, where it is determined in the fourth comparator 25 whether or not the above calculation 1adT/dθ is within the reference torque rate range set by the torque rate setting device 26, and if this determination is No, , the bolt B is considered to be improperly tightened, and the process proceeds to step S+s, where it is determined to be rNGJ. On the other hand, when the determination is YES, it is assumed that the bolt B is properly tightened, and a determination of rOKJ is made in step S+s. When the rotational torque T (tightening torque) of the nut runner 1 reaches the tightening torque 1aT4 set by the fourth torque setting device 29 after the judgment of "OK", the ON signal from the comparator 30 is set to the logic level. circuit 1
7 as a tightening completion signal, the operation of the nut runner 1 is stopped, and with this stop, the press-fitting and tightening device for the bolt B is completed.

Therefore, with the above operating procedure, the bolt B can be press-fitted into the bolt insertion hole W+ of the connecting rod body W without requiring a special device for press-fitting, such as a press-fitting press, and can be used to control the operation of the nut runner 1 used for tightening the press-fitting. This can be done with only slight corrections, and therefore, one nut runner 1 can continuously carry out the process from press-fitting the bolt B to tightening, thereby simplifying the device configuration and work contents in the bolt press-fitting and tightening work process. I can do it.

In the above embodiment, a case has been described in which the cap W' is integrally fastened to the connecting rod body W for an engine by press-fitting and tightening the bolt B. However, the present invention also provides for connecting various other members to each other using bolts having serrations. Of course, the present invention can also be applied to cases in which they are integrally fastened with nuts.

In the above embodiment, the tightening completion is controlled only by the rotation torque value of the nut runner, but it may be controlled by a combination of the torque value and the rotation angle of the nut runner.

(Effects of the Invention) As described above, according to the bolt press-fit tightening device of the present invention,
Based on the relationship between the time when the rotational torque of the nut runner to the bolt reaches the torque value generated during the bolt press-fitting and tightening processes under standard conditions, and the transition from the bolt press-fitting process to the tightening process. Since the bolt is determined to be properly press-fitted and the nut runner is stopped when the rotational torque of the nut runner reaches a set value during the bolt tightening process, a press-fitting press or the like is required to press-fit the bolt. The bolts can be press-fitted and tightened continuously using only the nut runner.
The device configuration and work contents in the bolt fastening process can be simplified.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and Fig. 1 is an overall configuration diagram of a bolt press-fitting and tightening device, Fig. 2 is an explanatory diagram showing the operating procedure of the device, and Fig. 3 is a diagram showing how to tighten a bolt while press-fitting it. FIG. 4 is an exploded perspective view of an engine connecting rod that is integrally fastened with bolts and nuts as a target of the press-fit tightening device. A... Bolt press-fit tightening device, 1... Nut runner,
6... Torque transducer, 8... First torque setting device, 9... Second torque setting device, 19... Press-fit timer, 21... Press-fit determination section, 22... Press-fit control Means, 28... Tightening control means, 29... Fourth torque setting device, W... Connecting rod body, Wl... Bolt insertion hole, B... Bolt, B+... Serration, N.・・・
Nut, Tl~T4...Torque value, 1+...Press-fitting time. Patent applicant: Mazda Motor Corporation

Claims (1)

[Claims] (1) A bolt with serrations on its shaft and a nut screwed onto the bolt are rotated relative to each other by a nut runner, and the bolt is press-fitted into the bolt insertion hole of the press-fitted member by the rotation, and then the bolt is tightened. The press-fitting tightening device includes a torque detector that detects the rotational torque of the nut runner, and a first torque setting device that sets a predetermined first torque value generated in the nut runner during the bolt press-fitting process, and a bolt press-fitting device. A second torque setting device that sets a second torque value that is larger than the first torque value that will be generated in the nut runner during the subsequent tightening process, and a press-fitting time required from the start of nut runner operation to the end of press-fitting the bolt. a timer to perform press-fitting, and a rotational torque of the nut runner detected by the torque detector exceeds a first torque value set by the first torque setting device within the press-fitting time by the timer, and a second
The press-fitting control means includes a press-fitting determination unit that determines that the bolt is in a proper press-fitting state when the second torque value set by the torque setting device is not reached, and the torque is detected during the tightening process of the bolt. 1. A bolt press-fitting tightening device comprising a tightening control means for stopping tightening by the nut runner when the rotational torque of the nut runner detected by the nut runner reaches a set value.