JP2002361525A - Method for inspecting assembly parts having seal member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for inspecting an assembly parts having a seal member capable of correctly determining acceptance or rejection of a screwing step and a pressing step of the parts having the seal member. SOLUTION: When the assembly parts having the seal member is assembled by screwing a fixing screw 9, the assembled condition via the seal member 10 of the assembly parts is inspected. When assembling the assembled part by screwing the fixing screw 9, the torque detection signal from a torque sensor 6 for detecting the screwing torque is sampled at each predetermined time, and the sampled torque data is stored. Next, a point B having the torque value b and a point A having the torque value a are obtained on the torque curve indicating the change of the torque to the time, and the area S of a substantially right triangle with the torque curve connecting the point A to the point B as a substantially hypotenuse is obtained. If the area S of the substantially right triangle is smaller than the preset reference value K, the assembly parts is accepted. If the area S is larger than the preset reference value K, the assembled part is rejected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection method for inspecting an assembled state of a part to be assembled via a sealing material when the part is assembled through a sealing material such as an O-ring.

[0002]

2. Description of the Related Art For example, a cover is placed via a sealing material such as an O-ring so as to cover an upper opening of a cylindrical body.
There is a part for fastening the cover to the main body with a plurality of fixing screws. When assembling these parts on an automated assembling line, a sealing material and a cover are placed on the main body and temporarily fixed using fixing screws. Then, the temporarily fixed assembly part is placed on the base of the screw tightening device,
With the tool of the screw tightening device fitted on the head of the fixing screw, the tool is lowered while rotating the tool, the fixing screw is screwed into the main unit through the cover, and the cover is tightened and fixed to the main unit. Will be

[0003] However, when assembling the cover component so as to be fastened and fixed to the main body via the seal material, the seal material is normally disposed in an annular groove formed on the main body, and
Whether or not a component has been assembled cannot be determined only by its appearance, so it is necessary to perform an inspection when the component is assembled.

[0004]

Conventionally, as a test method for screwing such a part with a seal material to a main body, a torque sensor is provided on a rotating portion of the screw tightening device, and the screw tightening device is temporarily fixed. When the fixing screw is screwed into the main body through the cover, the rotational torque when turning the screw is measured with time. When the torque rises abruptly at the final stage of screw tightening, the slope of a graph showing the change over time of the torque is obtained. If the slope of the graph is gentler than a predetermined value, the sealing material is attached to the main body and the cover. It was inspected to output a rejection judgment assuming that an assembly failure occurred due to the intrusion into a gap or the like.

[0005] However, in the graph showing the change in torque at the time of screw tightening, in the case of normal and the case of abnormal,
Since the difference in the inclination of the graph is small, there is a problem that the inspection accuracy is poor and it is difficult to accurately determine whether the screwing process of the part with the sealing material is good or not.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and provides a method of inspecting an assembled part with a seal material, which can accurately determine the quality of a screw tightening step or a press-fitting step of the part with the seal material. The purpose is to provide.

[0007]

In order to achieve the above object, a method for inspecting an assembly part with a seal material according to the first aspect of the present invention is to assemble the assembly part with a seal material by a screwing operation of a fixing screw. In this case, the inspection method is to inspect the assembled state of the assembled parts through the seal material, wherein a torque detection signal from a torque sensor for detecting a screw tightening torque of the fixing screw is sampled at predetermined time intervals, and the sampling is performed. Storing the obtained torque data, a first point having a first torque value and a second point having a second torque value are obtained on a torque curve indicating a change in the torque with respect to time, and the first point and the second point are obtained. A step of obtaining an area of a substantially right triangle having a torque curve connecting two points as a substantially hypotenuse; and, if the area of the substantially right triangle is smaller than a predetermined reference value, it is judged as pass, and the area is set to a predetermined reference value. If Ri large, characterized by comprising the steps of rejected, the.

According to a second aspect of the present invention, there is provided a method for inspecting an assembly part with a seal material, wherein when assembling the assembly part with a seal material by press-fitting the part, an assembly state of the assembly part via the seal material is inspected. A step of capturing and storing indentation load data in accordance with an indentation stroke at the time of indenting and press-fitting a part, and setting a local maximum position of a preceding stage as a first stroke position in advance in a load curve indicating a change in load with respect to the stroke. Then, the next minimum position of the load curve is set in advance as the second stroke position, the first load at the first stroke position and the second load at the second stroke position are obtained from the stored load data, and the second load is set in advance. The process falls within the reference value range that has been determined, and when the first load is greater than the second load, the pass is determined to be acceptable, otherwise, the process is rejected. And wherein the Mukoto.

[0009]

According to the inspection method of the first aspect, when assembling the assembly part with the sealing material by the screwing operation of the fixing screw,
This is to inspect the assembled state of the assembled parts via the sealant.When assembling the assembled parts by tightening the fixing screws, the torque detection signal from the torque sensor that detects the screw tightening torque is determined. Sampling is performed every time, and the sampled torque data is stored. Next, a first point having a first torque value and a second point having a second torque value are obtained on a torque curve indicating a change in the torque with respect to time, and a torque curve connecting the first point and the second point is obtained. The area of a substantially right triangle with as the hypotenuse is determined. If the area of the substantially right triangle is smaller than a preset reference value, it is considered as a pass,
If the area is larger than a preset reference value, it is rejected.

In this manner, the area of a substantially right triangle having a part of the torque curve as the hypotenuse is calculated, and the pass / fail judgment is made based on this area. As a result, the inspection accuracy is improved, and it is possible to accurately determine the quality of the assembly by screwing the component with the sealing material.

According to a second aspect of the present invention, when assembling an assembly part with a sealing material by press-fitting the part, the assembly state of the assembly part via the sealing material is inspected. At the time of press-fitting of a part, the load data is fetched and stored according to the pressing stroke. Next, in the load curve showing the change of the load with respect to the stroke, the maximum position of the preceding stage is set in advance as the first stroke position, the next minimum position of the load curve is set in advance as the second stroke position, and the stored load data is used. A first load at a first stroke position and a second load at a second stroke position are obtained. Then, when the second load falls within the preset reference value range and the first load is larger than the second load, it is determined to be acceptable, and otherwise, it is rejected.

As described above, if the assembled part with the sealing material is normally assembled, the load curve of the indentation load first has a maximum at the former stage and then descends once and then has a minimum. The maximum stroke is set as the first stroke position, the next minimum stroke is set as the second stroke position, and the first load at the first stroke position and the second load at the second stroke position are determined. Since the pass / fail judgment of the date is judged, the difference between normal and abnormal becomes clear,
The inspection accuracy is improved, and the quality of the assembly of the component with the sealing material can be accurately determined.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration diagram of an inspection device of a screw tightening device 1 used in the present inspection method. The screw tightening device 1 is a device for screwing when a cover component 7 is assembled to a main body component 8. Reference numeral 2 denotes a base of the screw tightening device 1, on which a screw tightening mechanism is mounted on a column erected on the base 2, and components to be assembled, that is, a main body part 8 and a cover part 7 are fixed on the base 2. Is placed in the position.

The screw tightening mechanism of the screw tightening device 1 includes a rotating unit 3 that rotationally drives the tool unit 5 fitted to the head of the fixing screw 9.
And a vertical operation unit 4 for moving the tool unit 5 up and down, and a torque sensor 6 for detecting a torque when the tool unit 5 is driven to rotate is mounted on the rotating unit 3.

As shown in FIG. 2, the main body part 8 is formed, for example, in a cylindrical shape, and a screw hole 8a for screwing a fixing screw 9 is formed in the upper surface thereof. The cover part 7 is the main body part 8
Is formed in a disk shape so as to close the upper opening, an annular groove 8b is formed in an annular shape on the upper surface of the main body part 8, and a sealing material 10 such as an O-ring is fitted into the annular groove 8b. A plurality of holes through which fixing screws 9 are inserted are provided in the peripheral portion of the cover component 7, and the fixing screws 9 pass through the holes, are screwed into screw holes 8 a of the main body component 8, and are temporarily fixed. The assembled body of the temporarily fixed main body component 8, the cover component 7, the sealing material 10, and the fixing screw 9 is placed at a predetermined position on the base 2 of the screw tightening device 1, as shown in FIG.

Such a screw tightening apparatus 1 is installed on, for example, a fully automated production line, and products such as the main body part 1 temporarily fixed are placed on a predetermined position of a base 2 by a robot hand or the like (not shown). To change its position, and is taken out when screwing is completed. During the screw tightening process, the torque detection data from the torque sensor 6 for detecting the screw tightening torque is taken into the inspection device 11, and the fixing state of the cover component 7 including the sealing material 10 is inspected.

The inspection apparatus 11 is composed of a personal computer having a display, a printer, and the like. When the inspection is started, the CPU samples the torque data from the torque sensor 6 every predetermined sampling time, and stores the data in the storage unit. To memorize. Then, the inspection device 11 detects a point B at which the sampling torque reaches the preset torque value b.
Is obtained, and a point A at which the sampling torque reaches a preset torque value a is obtained.

Here, the torque value b is the initial torque value at which the fixing screw 9 is screwed in and the head thereof comes into contact with the cover part 7, and finally the step of tightening the main body part 8 and the cover part 7 is started. a is a torque value immediately before the screwing of the fixing screw 9 is completed, and is a case where the relationship of torque value a> torque value b is satisfied. Then, the inspection device 1
1 obtains the area of a triangle having the hypotenuse of the point A and the point B. If the area S is smaller than the reference value K, the inspection apparatus 11 determines that the screw tightening is passed, and the area S is the reference value K If it is larger, it is determined that the screw tightening has failed.

Next, a method for inspecting an assembled part with a sealing material, which is performed by using the inspection device 11 and the screw tightening device 1, will be described.
This will be described with reference to the flowchart of FIG. First, a main body part 8, a cover part 7, a sealing material 10, and a fixing screw 9 temporarily fixed by operating a robot hand or the like (not shown).
Is mounted at a predetermined position on the base 2 of the screw tightening device 1. In this state, the screw tightening device 1 operates,
The vertical operating unit 4 lowers the tool unit 5, and fits the tool unit 5 to the head of the fixing screw 9. Then, the rotating part 3 turns the tool part 5 in the screwing direction to start screw tightening (step 10).
0) At the same time, sampling of torque is started (step 110).

The sampling is performed by sampling the torque data from the torque sensor 6 every predetermined sampling time, and all the data sampled during the screw tightening process is stored in the storage unit of the inspection device 11. Thereafter, the inspection device 11 obtains a point B exceeding the torque value b while checking the data stored in the storage unit in step 120, and further obtains a point A exceeding the torque value a in step 130. .

As mentioned above, the torque value b is
Is the initial torque value at which the head of the cover member 7 comes into contact with the cover component 7 and finally the process of tightening the main body component 8 and the cover component 7 is started. The torque value a is the torque immediately before the screwing of the fixing screw 9 is completed. Value. That is, a period in which the slope of the torque graph in which the torque graph rises in the final stage of the tightening process is obtained. And
In step 140, the inspection device 11 obtains an area S of a right triangle having the points A and B as hypotenuses.

[0022] If the sampled torque value trq (n) to the sampling time width t, the equation of _{^{S = Σ a n = b trq}} (n) × t, it is possible to obtain the area S.

Then, the inspection apparatus 11 performs step 150
If the area S is smaller than the preset reference value K, the process proceeds to step 160, and it is determined that the area is acceptable, and a pass process is performed. If the area S is larger than the preset reference value K, the process proceeds to step 170. Rejection is determined, and rejection processing such as excluding the assembled part as a defective product is performed.

As shown in FIG. 4, the sealing material 10 is
When the cover part 7 is correctly fitted in the upper annular groove 8b and is properly seated on the main body part 8, the screwing torque of the fixing screw 9 sharply increases from the state where the cover part 7 is seated. For this reason, as shown in the graph of FIG.
The area S of the right triangle having the point B as the hypotenuse is smaller than the reference value K.

On the other hand, as shown in FIG. 5, when the sealing material 10 is sandwiched between the main body part 8 and the cover part 7 and bites, the screwing torque of the fixing screw 9 is such that the cover part 7 is seated. Even in a state where it does, it does not rise rapidly but rises relatively slowly. Therefore, as shown in the graph of FIG. 7, the area S of the right triangle having the points A and B as hypotenuses is larger than the reference value K, and as shown in FIG.
If the reference value K is a little below the area S when the fitting is abnormal and the fitting is abnormal, the defective product in a case where the sealing material 10 is caught and bitten between the main body component 8 and the cover component 7 is considered. , Can be reliably found by this inspection.

FIGS. 8 to 14 show another embodiment. In this embodiment, when the press-fitting part 27 is pressed into the main body part 28 using the press device 21, the assembled state of the assembled parts is changed. inspect.

Reference numeral 22 denotes a base of the press device 21. A press mechanism is mounted on a support on the base 22.
The components to be assembled, that is, the main component 28 and the press-fit component 27 are placed on the top 2. The press device 21 is provided with, for example, a servo press mechanism, and a slider 23 mounted movably up and down has a main body component 28 mounted on a base 22.
It is arranged so that the press-fitting part 27 on the top may be pressed from above. A load sensor 24 for detecting a load applied to the slider 23 when the slider 23 is pressed down is mounted. The slider 23 is provided with a stroke detector such as a linear scale that outputs a signal indicating a stroke length according to the stroke when the slider 23 slides up and down. The stroke detector and the load sensor 24 are input to an inspection device 31 described later. Connected to the side.

As shown in FIG. 9, the main body part 28 is formed, for example, in a cylindrical shape, and the press-fitting part 27 is formed by providing a disk-shaped flange part 27b on a cylindrical part 27a. At the time of assembly, the portion 27a enters the main body component 28, and the flange portion 27b is seated on the upper surface of the main body component 28. An annular groove is formed in the cylindrical portion 27a of the press-fitting part 27, and a sealing material 3 such as an O-ring is formed in the annular groove.
0 is fitted to seal between the main body part 28. The main body part 28 and the press-fitting part 27 are placed at predetermined positions on the base 22 of the press device 21 with the column part 27a inserted into the main body part 28.

The pressing device 21 is installed on, for example, a fully automated production line,
The assembly parts 8 and the like are placed on a predetermined position of the base 22 by a robot hand (not shown) or the like, and are unloaded when the assembly is completed. During the press-fitting (push-in) process of the press-fitting part 27, detection data from the load sensor 24 for detecting the pushing load is taken into the inspection device 31 together with the stroke length detection data of the slider 23, and the press-fitting part 27 including the sealing material 30 is provided. Is inspected.

The inspection device 31 is composed of a personal computer having a display, a printer and the like as described above. When the inspection is started, in response to the descending operation of the slider 23, together with the stroke length data, ie, a unit stroke signal The load data from the load sensor 24 is fetched every time is input, and is stored in the storage unit.

Then, the inspection device 31 obtains the load F1 at the time of the stroke S1 of the slider 23,
The load F2 at the time of is obtained. Stroke S of slider 23
Reference numeral 1 denotes a front part of a normal pushing operation, which is set in advance as a stroke length at which a maximum load is once generated, and a stroke S
Reference numeral 2 denotes a middle portion of a normal pushing operation, which is set in advance as a stroke length at which a load temporarily drops and a minimal load is generated.

As described above, the inspection device 31 obtains the load F1 at the time of the stroke S1, and also obtains the load F2 at the time of the stroke S2.
If the load is between _min and the maximum value _Kmax , and the load F1 is larger than the load F2, it is determined that the press-fitting has been performed well, and a pass is determined. In other cases, the press-fit is poor due to the sealing material being bitten or the like. Is judged as having occurred, a rejection determination is made.

Next, the inspection device 31 and the press device 2
Inspection method of assembly parts with seal material performed using
This will be described with reference to the flowchart of FIG. First, an unillustrated robot hand or the like is operated to place the temporarily fixed main body part 28, the press-fit part 27, and the assembled part of the sealant 30 at a predetermined position on the base 22 of the press device 21. In this state, the press device 21 operates, the slider 23 descends, and the slider 23 presses the upper part of the press-fitting part 27 from above, and the pushing starts (step 20).
0).

When the pushing operation is started, step 2
At 10, the detection data of the stroke length and the pushing load of the slider 23 is taken into the inspection device 31. All the detection data of the stroke length and the pushing load are stored in the storage unit of the inspection device 31. And the inspection device 31
Pressing (pressing) of the press-fit part 27 by the press device 21
Is completed, the load F1 at the time of the stroke S1 is obtained from the stored stroke length and load data (step 2).
20), a load F2 at the time of the stroke S2 is obtained (step 230). As described above, the stroke S1 is a stroke length at which a maximum load is once generated at the front stage of the normal pushing operation, and the stroke S2 is a stroke length at the middle stage of the normal pushing operation when the load temporarily drops to generate the minimal load. Stroke length.

Next, the inspection device 31 proceeds to step 240
Then, it is determined whether the load F2 at the time of the stroke S2 is between the predetermined minimum value _Kmin and the maximum value _Kmax , that is, within the range of the reference value, and the load F2 at the time of the stroke S2 is set at the predetermined minimum value. If not between the value K _min and the maximum value K _max ,
It is rejected as an abnormal load state. On the other hand, when the load F2 at the time of the stroke S2 is between the preset minimum value _Kmin and the maximum value _Kmax , it is further determined in step 250 whether the load F1 is greater than the load F2.
Is smaller than the load F2, it is rejected.

That is, as shown in FIG. 14, when the sealing material 30 is caught in the gap in the main body part 28 and bites, the sealing material 30 does not fit in a stable position. As shown in (1), the pushing loads F1 and F2 increase according to the stroke length of the slider 23. For this reason, in the case where the press-fitting component 27 is not properly pushed, the load F2 at the time of the stroke S2 becomes larger than the load F1 of the stroke S1, and it is determined that the load F2 is unacceptable.

On the other hand, as shown in FIG.
When the press-fitting part 27 is normally press-fitted into the inside and the sealing material 30 is in a state of sealing the inside of the main body part 28 satisfactorily, the load F2 at the time of the stroke S2 is a predetermined minimum value _Kmin.
And the maximum value _Kmax , and as shown in FIG. 12, the load F1 at the time of the stroke S1 is the load F2 of the stroke S2.
Be larger. Therefore, Step 240 and Step 2
If 50 is established, the process proceeds to step 260, where it is determined to be acceptable, and a pass process is performed.

[0038]

As described above, according to the first aspect of the present invention,
According to the inspection method of the assembled part with the sealing material, the area of a substantially right triangle having a part of the torque curve obtained at the time of screw tightening as the hypotenuse is calculated, and a pass / fail judgment is made based on this area. Therefore, the difference between the normal and abnormal cases can be set large, the inspection accuracy can be improved, and the quality of the screw tightening process of the part with the sealing material can be accurately determined. In the inspection method according to the second aspect, if the assembled part with the sealing material is normally assembled, the load curve of the indentation load first has a local maximum at the former stage, and then temporarily descends to generate a local minimum. From
This maximum stroke is set as a first stroke position, the next minimum stroke is set as a second stroke position, and the first load at the first stroke position and the second load at the second stroke position are determined. Since the pass / fail of the assembly is determined, the difference between normal and abnormal becomes clear,
The inspection accuracy is improved, and it is possible to accurately determine whether the assembly of the component with the sealing material is good or bad.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and is a schematic configuration diagram of an inspection device including a screw fastening device 1 for performing the inspection method.

FIG. 2 is an exploded perspective view of an assembly component.

FIG. 3 is a flowchart illustrating an inspection method.

FIG. 4 is a cross-sectional view of a state in which a cover component is normally fixed on a main body component.

FIG. 5 is a cross-sectional view of a state in which the sealing member is engaged in the gap and the cover component on the main component is fixed in an inclined state.

FIG. 6 is a graph showing a change in torque with respect to a normal time.

FIG. 7 is a graph showing a change in torque with respect to time at the time of abnormality.

FIG. 8 is a schematic configuration diagram of an inspection device including a press device 21 for performing an inspection method according to another embodiment.

FIG. 9 is an exploded perspective view of an assembly component.

FIG. 10 is a flowchart for carrying out the inspection method.

FIG. 11 is a cross-sectional view showing a state in which a press-fit component is normally pressed and pressed into a main component.

FIG. 12 is a graph showing changes in stroke length and load in the same state.

FIG. 13 is a graph showing a change in a stroke length and a load in a state where the sealing material is engaged in the gap.

FIG. 14 is a cross-sectional view of a state where the press-fitting component is pushed into the main body component in a state where the sealing material is engaged in the gap.

[Explanation of symbols]

 1-Screw fastening device 6-Torque sensor 7-Cover component 8-Body component 9-Fixing screw 10-Seal material 11-Inspection device 21-Press device 24-Load sensor 27-Press-fit component 28-Main component 30-Seal material 31 -Inspection equipment

Claims (2)

[Claims] 1. An inspection method for inspecting an assembled state of a part with a sealing material via a sealing material when assembling the part with the sealing material by a screw tightening operation of the fixing screw, the method comprising: Sampling a torque detection signal from a torque sensor for detecting a tightening torque at predetermined time intervals, storing the sampled torque data, and having a first torque value on a torque curve indicating a change in the torque with respect to time. Obtaining a first point and a second point having a second torque value, obtaining an area of a substantially right triangle having a torque curve connecting the first point and the second point as a substantially hypotenuse; and A step of rejecting if the area is smaller than a preset reference value, and rejecting if the area is greater than a preset reference value, wherein: Inspection method. 2. An inspection method for inspecting an assembled state of a part with a seal material through a seal material when assembling the part with a seal material by the press-fitting of a part. And loading and storing the indentation load data in accordance with the following. In the load curve indicating the change of the load with respect to the stroke, the maximum position of the preceding stage is set in advance as the first stroke position, and the next minimum position of the load curve is set in advance. The second stroke position is set, the first load at the first stroke position and the second load at the second stroke position are determined in the stored load data, and the second load falls within a preset reference value range. And a process in which when the first load is greater than the second load, the pass is judged to be acceptable; otherwise, the process is rejected. Inspection method for assembled parts.