JPH04141328A - Abnormally detecting method for press fitting - Google Patents

Abstract

PURPOSE:To correctly detect the press fitting abnormality of a work, by performing the check of a press fitting state on each simple substance of the press fitting part, with respect to those which are slid at their press fitting start time, by the plural press fitting parts provided on the work. CONSTITUTION:A press fitting abnormality is detected by a load cell 2 based on the press fitting load of the case of the work equipped with plural press fitting parts press-fitted with a time slippage in the same direction being fixed with its press fitting to the specified assembly position in once press fitting cycle. In this case, the load applied on the work in the course from the press fitting start to press fitting completion is detected, it is stored as a press fitting load characteristic, the difference in the lowest value of the press fitting load values in the source from the peak to the next peak in this press fitting load characteristic and the press fitting load value in the next peak is operated by a decision unit 10, and it is decided as to whether or not this operation value is within a preset allowable range.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for detecting a press-fitting abnormality in a workpiece having a plurality of press-fitting portions that are press-fitted in the same direction with a time lag.

[Conventional technology]

To detect a press-fitting abnormality when a workpiece is press-fitted into a predetermined position of a part, first, the load applied to the workpiece from the start of press-fitting to the end of press-fitting is detected by a load cell, etc., and this is calculated as the press-fitting load. Store as a characteristic. Next, it is determined whether the peak (maximum value of press-fit load) in this press-fit load characteristic is within an allowable range. and,
If the pic value is not within the allowable range, it is determined that there is a press-fitting abnormality.

In addition, if the workpiece has multiple press-fit parts that are press-fitted in the same direction with a time lag, the peak press-fit load value caused by the press-fit of each press-fit part will be different in the press-fit load characteristics. Determine whether it is within the allowable range. If each peak value is not within the respective allowable range, it is determined that there is a press-fit abnormality.

Here, the plurality of press-fitting portions described above each have a time lag in the timing at which press-fitting starts, and the timing at which each press-fitting ends is the same. Therefore, when the final press-fitting part is press-fitted, the first press-fitting part is still being press-fitted.

That is, the press-fitting load characteristic represents the sum of the loads applied to each press-fitting part.

[Problem to be solved by the invention]

According to the conventional method, a press-fitting abnormality is detected based on the peak value of the press-fitting load applied to the workpiece.

For example, if we consider a case where a workpiece has two press-fitting parts that are press-fitted in the same direction, the first peak of the press-fitting load value that occurs after the start of press-fitting, that is, the maximum press-fitting load of the press-fitting part that is press-fitted first. It is determined whether the value is within an acceptable range.

Next, the second peak of the press-fitting load value, that is, the sum of the maximum press-fitting load value of the second press-fitting part and the stable press-fitting load value of the first press-fitting part, is calculated. It is determined whether or not it is within the allowable range.

However, if the second peak value of the press-fitting load is determined to be abnormal, check whether the cause is due to the stable press-fitting load value of the first press-fitting part.
Alternatively, it is not possible to determine whether the cause is the maximum press-fitting load value due to the second press-fitting part. Also,
On the other hand, even if it is determined to be normal, if the stable press-fitting load value of the first press-fitting part is small and the maximum press-fitting load of the second press-fitting part is larger than the allowable value, It is also possible that the sum of both is within the permissible range.

The technical problem of the present invention is to calculate the maximum press-fit load value applied to each press-fit part from the press-fit load characteristics representing the load applied to the workpiece based on two-dimensional knowledge, and set this value to a normal value. It is an object of the present invention to provide a method for accurately detecting a press-fitting abnormality in a workpiece by checking the press-fitting state of each press-fitting part by comparing with the press-fitting state of the press-fitting part.

[Means to solve the problem]

The above problem is solved by the press-fit abnormality detection method of the present invention, which will be described below.

That is, in a method of detecting a press-fitting abnormality based on a press-fitting load when a workpiece having a plurality of press-fitting parts that are press-fitted in the same direction with a time lag is press-fitted and fixed at a predetermined assembly position in one press-fitting cycle. , detects the load applied to the workpiece from the start of press-fitting to the end of press-fitting, and stores this as a press-fitting load characteristic.

Then, the difference between the lowest value of the press-fit load value between the peak and the next peak in the press-fit load characteristic and the press-fit load value at the next peak is calculated.

Furthermore, it is determined whether this calculated value is within a preset allowable range.

[For production]

According to the present invention, first, the lowest value of the press-fit load value between one peak and the next peak in the press-fit load characteristic is determined.

Here, to simplify the explanation, if the peaks are considered as the first peak and the second peak, the first peak indicates the maximum press-fitting load value of the press-fitting part that is press-fitted first. The second peak indicates the sum of the stable press-fitting load value of the first press-fitting part and the maximum press-fitting load value of the second press-fitting part.

Therefore, the lowest value of the press-fitting load value between the peak and the next peak indicates the stable press-fitting load value of the press-fitting part that is press-fitted first.

Therefore, the difference between the minimum press-fit load value and the press-fit load value at the second peak means the maximum press-fit load value applied to the second press-fit unit alone.

Then, by comparing this value with an allowable value, the press-fitting state of the second press-fitting part is determined.

As described above, according to the workpiece press-fitting abnormality detection method according to the present invention, if the press-fitting start time deviates between multiple press-fitting parts provided on the workpiece, the maximum press-fitting load value applied to each press-fitting part alone can be calculated. Since each can be determined, the press-fit condition of each press-fit portion can be checked.

〔Example〕

EMBODIMENT OF THE INVENTION Hereinafter, the press-fit abnormality detection method based on 1st Example of this invention is demonstrated concretely with reference to drawings.

FIG. 3 is a perspective view showing an injector 20 that intermittently injects and supplies fuel to an engine (not shown) and a delivery 40 that supplies fuel to the injector 20. Also, Figure 4 shows the injector 20 and delivery 4.
The assembly with 0 represents a cross-sectional view.

The injector 20 has a delivery 4 as shown in FIG.
The fuel supplied through the fuel passage 42 of the delivery 40 is guided into the interior through the filter 21 on the side, and is then delivered from the fuel injection hole 23 at the tip at a predetermined timing. Inject.

Here, the injector 20 is equipped with a seal ring 22.24 for sealing fuel on the outer periphery and an insulator link 26 for absorbing vibration, and the delivery 40 is carried out via the link 22.24.26. Fixed.

A press fitting method is used to attach the injector 20 to the delivery 40. In this case, the injector 20 and the delivery 4o do not come into direct contact with each other, and the seal link 22.24 and the insulator link 26
is sandwiched between the outer peripheral surface of the injector 20 and the inner wall surface of the delivery 40 and is press-fitted without being deformed. That is, they correspond to the seal rings 22, 24, the insulator ring 26, and the press-fitted parts of the injector 20.

Here, the seal links 22, 24 are attached to the large diameter portion at the approximate center of the injector 20 with the filter 21 in between, and the insulator ring 26 is attached to the small diameter portion at the tip of the injector 20.
It is installed coaxially with 24. Therefore, when the injector 2o is press-fitted into the inside of the delivery 40, the seal rings 22, 24 come into contact with the delivery 40 earlier than the insulator ring 26, and press-fitting is started, and after sliding for a predetermined stroke, , insulator ring 2
6 is pressed into contact with the delivery 40. Then, with the injector 20 inserted into the delivery 4o by a specified length, the press-fitting of the seal ring 22, 24 and the insulator link 26 is completed.

Further, the injector 20 is firmly attached to the delivery 40 by being pressed by the cover member 6 via the upper insulator ring 28.

FIG. 1 is an overall block diagram of an apparatus for detecting a press-fitting abnormality between the seal rings 22, 24 and the insulator ring 26 when the injector 20 is press-fitted into the delivery 40.

In the figure, reference numeral 2 denotes a load cell, which continuously measures the press-fitting load when the workpiece, that is, the injector 20 is press-fitted into the delivery 40 by the press-fitting device 1.

The analog output signal from the load cell 2 is input to the press-fit state determining device 10, where it is digitally converted and stored in a memory. Then, data processing is performed using a method to be described later, and the press-fit state is determined.

The result of the determination of the press-fit state is displayed on the display device 12.14.16.

FIG. 2 is a control flowchart for detecting a press-fit abnormality, which is executed in the press-fit state determination device 10.

The processing according to this flowchart is repeatedly executed every 0.05 seconds. In addition, since the time required for press-fitting is approximately 3 seconds, it is possible to obtain the data necessary to determine the press-fitting state even if the processing time takes 0.05 seconds.
There is no particular problem.

First, when press-fitting is started from the seal ring 2224 portion of the injector 20, the process proceeds from step 100 via step 101, step 102, and step 103 to step 104, where press-fitting load data P is read.

Then, in step 105, 1 is added to the number N of times the process has been performed. If this is the first time processing, N=1. That is, by multiplying the processing time (0.05 seconds) by the number of times N of processing has been performed, it is possible to measure the time from when press-fitting is started.

Then, the above process is repeatedly executed during press-fitting, and the judgment in step +02 becomes YES at the timing when press-fitting of the insulator ring 26 is started, that is, when the press-fitting of the seal ring 22.24 portion is stable. , processing proceeds to step 106. Then, the press-fit load characteristics are determined from the press-fit load data P and time T (0,05XN) that have been read so far, and PImax, which is the peak value in the press-fit load characteristics, is selected.

Here, Plmax is the maximum press-fitting load applied to the seal ring 22.24, and is the load value before the seal ring 22.24 comes into contact with the inner wall surface of the delivery 40, deforms, and stabilizes.

Next, in step 107, the value of Plmax and the allowable value P1 are compared. Here, Pl is a load value determined in advance through experiments.

If Plmax>PI, the press-fitting of the seal rings 22, 24 is abnormal, and the process proceeds to step 109, where a press-fit NG display is made, and the press-fit operation is stopped at step 110. Then, in step 111, the press fitting normal flag F is cleared and the process is returned to the start position.

If Plmax<PI, the press-fitting of the seal rings 22, 24 is normal, and in step 108, the press-fitting normal flag F is set to 1, and the process is returned to the starting position. Here, F
= 1, so the decision in step 1, O] is YES.
Therefore, in the next processing, step 102 is bypassed, the process proceeds from step 103 to step 104, and the press-fit load data P is read again. Then, in step 105, N is counted.

In this way, while the above process is repeatedly executed, when the press-fitting is completed, the judgment in step 103 becomes YES,
The process clears flag F in step 112 and proceeds to step 1.3.

In step 113, the press-fit load characteristics are determined from the press-fit load data P and time T (0,05xN) read so far, the second peak value P2max in the press-fit load characteristics is selected, and the first peak P], ma
Plmin, the minimum value of the data obtained between X and P2ma, which is the second peak value, is selected.

An example of the press-fit load characteristics obtained in step 1) 3 is shown in
As shown in the figure.

Here, Plmin is the press-fitting load value of the seal ring 22.24 in a stable state, and Plmin is the press-fitting load value of the seal ring 22.24
This is the load value when the delivery member 40 is sliding stably after a predetermined period of time has elapsed after contacting the inner wall surface of the delivery member 40 and being deformed.

Furthermore, the second peak value P2max is the maximum press-fitting load value of the insulator ring 26 and the seal ring 22
．． 24 represents the sum of press-fitting load values (Plmin) in a stable state. Here, the maximum press-fitting load value of the intulator ring 26 is the load value before the intulator link 26 comes into contact with the inner wall surface of the delivery 40, deforms, and stabilizes.

Next, in step 114, the difference between P2max and Plmin, that is, the maximum press-fitting load value applied to the insulator ring 26 alone is calculated, and this value is compared with the allowable value P2.

Here, the allowable value P2 is a load value determined in advance through experiments.

If P2max - P lm1n <P2, the press-fitting of the insulator ring 26 is normal, and press-fitting OK is displayed in step +15, and the process is returned to the starting position.

If P 2max - P lm1n <P 2 , the press-fitting of the insulator link 26 is abnormal, and press-fitting NG is displayed in step 116, and the process is returned to the starting position.

Thus, according to this embodiment, the seal link 22.
24 and insulator ring 2G, the seal υ
It is possible to check whether each of the puffers 22, 24 or the insulator ring 26 is press-fitted.

Therefore, the press-fitting state of the injector 20 is accurately detected.

FIG. 6(a) is a press-fit state diagram of the injector 20 according to the second embodiment of the present invention, and FIG. 6(l) is a sectional view of the insulator ring 126.

Insulator ring 1 used in this example
26 is approximately the same in shape and function as the insulator ring 26 used in the first embodiment, but
The installation procedure is different. That is, the injector 20
At the time of press-fitting, the insulator link 12G is attached to the delivery 40 side separately from the injector 20 in advance, and is fixed at a predetermined position between the injector 20 and the delivery 40 when the press-fitting is completed.

Here, the outer diameter DI of the insulator ring 126 is smaller than the inner diameter of the delivery 40, and the inner diameter D2
is made larger than the outer diameter d of the tip of the injector 20. However, the insulator ring 12
6 has variations of about ±α in the outer diameter DI and ±β in the inner diameter D2 for each product, and the manufacturing accuracy is not very high. For this reason, even if the insulator link 126 is installed at a predetermined position on the delivery 40, the axis of the injector 20 and the center of the insulator ring 126 are largely misaligned, and the tip of the injector 20 is attached to the insulator ring 126 during press-fitting. may be destroyed.

In the press-fitting abnormality detection method according to this embodiment, the press-fitting load during normal press-fitting of the insulator link 126 is determined experimentally, and this value is set as the allowable value P2. Then, calculate the maximum press-fitting load to be applied to the insulator ring 126 alone in the same manner as in the first embodiment,
This value is compared with the allowable value P2 to check the press-fit condition.

〔Effect of the invention〕

According to the present invention, if the press-fitting start time of a plurality of press-fitting parts provided on a workpiece is different, the press-fitting state can be checked for each press-fitting part.
Press-fit abnormalities in the workpiece are accurately detected.

[Brief explanation of drawings]

Fig. 1 is an overall block diagram of a press-fitting abnormality detection device used in the first embodiment of the present invention, Fig. 2 is a control flowchart for detecting press-fitting abnormalities, and Fig. 3 shows an injector 20 and an injector to be press-fitted. Delivery 40 that stores 20
FIG. 4 is a perspective view of the injector 20 housed inside the delivery 40, FIG. 5 is a press-fit load characteristic diagram, and FIG. 6 is a press-fit state of the injector 20 according to the second embodiment of the present invention. It is a diagram. 2...Load cell (load detection means) 10...Press-fitting state determination device step 113...Press-fitting load characteristic step 114...Press-fitting state determining means 0...Injector (work) 2...Seal ring (Press fit part) 4... Seal ring (Press fit part) 6... Insulator ring (Press fit part) 0... Delivery

Claims (1)

[Claims] A press-fitting abnormality is detected based on the press-fitting load when a workpiece having a plurality of press-fitting parts that are press-fitted in the same direction with a time lag is press-fitted and fixed at a predetermined assembly position in one press-fitting cycle. In the detection method, the load applied to the workpiece from the start of press-fitting to the end of press-fitting is detected, this is stored as a press-fitting load characteristic, and the press-fitting load between the peak and the next peak in this press-fitting load characteristic is detected. A workpiece press-fitting abnormality characterized by calculating the difference between the lowest value and the press-fitting load value at the next peak, and determining whether or not this calculated value is within a preset tolerance range. Detection method.