KR20160011060A - Method for inspecting rivetting portions of metal panel - Google Patents

Abstract

The present invention provides a method to inspect riveting of a self-piercing rivet apparatus to rivet a metallic panel (Pa, Pb) by a punch and an anvil. The inspection method of the present invention comprises: a data setting process of setting a standard range for displacement and load of the punch in one stroke process for riveting; an upper panel judgment process of judging whether the load corresponding to at least one displacement position on a same position is included in the standard load range, or judging whether the displacement corresponding to at least one load to the same load is included in the standard displacement range during a process where a rivet presses an upper panel; and a lower panel judgment process of judging whether a gradient of the load to the displacement belongs to a standard gradient range during the process that the rivet passing through the upper panel presses the lower panel. Moreover, the method of the present invention may further include a process of judging whether a maximum displacement and a maximum load at a maximum displacement position of the rivet to the lower panel belongs to a range of a standard maximum displacement and a standard maximum load after the upper panel judgment process.

Description

Technical Field [0001] The present invention relates to a method of inspecting rivetting portions of a metal panel,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of inspecting a rivet joint of a metal panel, and more particularly, to a method of inspecting a rivet joint of a metal panel using a load and a displacement of a punch used for a rivet joint, And a method for testing a joint.

For example, in the process of producing various machinery including automobiles, it is often necessary to connect two metal panels. For example, even when a plurality of metal panels are connected to form a chassis of an automobile, two metal panels (hereinafter, simply referred to as panels) must be connected. In addition to such automotive fields, metal panels are connected to construct structures in various technical fields.

Various methods are used to connect the two metal panels in this way. For example, welding including spot welding or riveting using rivets is widely used. Here, connecting the panels by spot welding is advantageous in terms of cost, but it can be applied only when the two panels are made of a weldable material. For example, such spot welding can be useful when connecting two steel panels together, but it is quite disadvantageous to connect different panels such as steel and aluminum.

Rivetting is a somewhat disadvantageous aspect in terms of cost, but it can be said that it is widely used due to the advantage that different kinds of materials can be easily connected. In this case, a self-Piercing Rivet (SPR) . The basic principle of this self-piercing rivet device is shown in Fig. As shown in the figure, the self-piercing rivet device is a device for connecting two panels Pa and Pb using rivets, and includes a punching portion 10 including a punch 12, And a die or anvil 20 for supporting an applied load. Such a self-piercing rivet device is mounted on an end of a multi-axis robot and sequentially rivets the panel of the corresponding part in accordance with the programmed process in the production line.

The rivet used in such a self-piercing rivet device may use a rivet R having a leg portion Ra protruding in a circular shape at a lower end thereof. However, it goes without saying that the inspection method described below can not be limited to this type of rivet (R). FIG. 2 schematically shows a process of connecting the two panels Pa and Pb using the rivet R. FIG.

As shown in the figure, in the process (a), the punch 12 is inserted into the end portion of the rivet R. In the process (b), the punch 12 is moved downward by the hydraulic pressure, And begins to press on the panel. And, in the process (c), when the rivet R passes through the upper panel and continues to pass completely to the lower panel as shown in (d), the two panels Pa and Pb The process is complete.

Such a self-piercing rivet device is installed in a state in which it is set in an optimal condition after performing a plurality of tests so as to perform a normal operation with respect to two panels to be combined before being put into an actual line. Here, for the normal operation of the self-piercing rivet device, the pressing force for pressing the panels Pa and Pb, that is, the load and the moving distance, i.e., displacement, of the punch 12 is one of the most important factors have.

Therefore, a sensor capable of measuring a load applied to the anvil 20 by displacement and punching of the punch 12 is mounted. Based on the information measured by the sensor, two panels (Pa , Pb) can be normally set to be rivetted, and then put into the actual manufacturing process.

However, in actual manufacturing processes, it is not appropriate to accurately check whether the riveting process has been performed correctly with respect to the product being produced. That is, in the actual manufacturing process, various parameters may exist. For example, the rivet itself supplied to the apparatus may be a defective product, and the rivet itself may not be set correctly in the punch 12 described above Of course. Even if the rivet is normal and normally set in front of the punch 12, there is a possibility that defects may occur in the process of riveting by the self-piercing rivet device.

For the time being, it is difficult to check whether a rivet is more complete as in the case of a full inspection, since it is only possible to determine whether the rivet joint is bad in the overall process by visually identifying the appearance of the product produced in the manufacturing process. Can not.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an inspection method capable of precisely grasping whether or not a rivet joint is defective with respect to all manufactured products.

As described above, the present invention can be said to precisely grasp whether the above-described self-piercing rivet device is in normal operation, and it can be said that the present invention is based on the value of the load and displacement that can be sensed in the self- And the most accurate inspection method is provided.

According to an aspect of the present invention, there is provided a punch comprising: a punch for pressing a rivet while linearly reciprocating in a predetermined section; and an anvil provided so as to correspond to the punch with a pair of metallic panels, As a rivet inspection method of a rivet device; A data setting step of setting a standard range for the displacement and the load of the punch in one stroke process for riveting; It is determined whether or not the corresponding load is included in the standard load range in at least one displacement position in the process of pressing the upper panel by the rivet or whether or not the displacement corresponding to the at least one load is included in the standard displacement range An upper panel judgment process; And a maximum displacement and load determining process for determining whether the rivet passing through the upper panel determines whether the maximum displacement and the maximum load at the maximum displacement point of the punch in the lower panel belong to the standard maximum displacement and the standard maximum load. do.

The method may further include determining whether a maximum displacement and a maximum load at a maximum displacement point of the rivet with respect to the lower panel belong to a standard maximum displacement and a standard maximum load after the upper panel determination process.

According to another embodiment of the present invention, there is provided a rivet joint of a self-piercing rivet device including a punch for linearly moving a rivet, and an anvil provided so as to correspond to the punch with a pair of metallic panels as a bonding object interposed therebetween By inspection method; A data setting step of setting a standard range for the displacement and the load of the punch in one stroke process for riveting; A lower panel judging step of judging whether or not a slope of a load with respect to displacement is within a standard slope range when a rivet penetrating the upper panel presses the lower panel; And determining the maximum displacement and the maximum load at the maximum displacement point of the punch in the range of the standard maximum displacement and the standard maximum load with the rivet being pressed into the lower panel as far as possible, .

According to another embodiment of the present invention, there is provided a rivet joint of a self-piercing rivet device including a punch for linearly moving a rivet, and an anvil provided so as to correspond to the punch with a pair of metallic panels being a bonding object interposed therebetween By inspection method; A data setting step of setting a standard range for the displacement and the load of the punch in one stroke process for riveting; It is determined whether or not the corresponding load is included in the standard load range in at least one displacement position in the process of pressing the upper panel by the rivet or whether or not the displacement corresponding to the at least one load is included in the standard displacement range An upper panel judgment process; And a maximum displacement and load determining process for determining whether the rivet passing through the upper panel determines whether the maximum displacement and the maximum load at the maximum displacement point of the punch in the lower panel belong to the standard maximum displacement and the standard maximum load. do.

The data setting process is preferably performed based on a plurality of displacements of the punch and a plurality of load information measured when the rivet joint is normally performed. The standard range set in the data setting process can be updated using data generated in a subsequent riveting operation.

In the upper panel determination process, it is determined whether or not the load corresponding to the displacement at the first position of the punch is included in the standard load range, and whether the displacement corresponding to the load at the second position of the punch is included in the standard displacement range It is preferable to judge.

According to the method of the present invention as described above, it can be seen that whether the rivet joint is normal or not is determined based on accurate data on the load of the punch applied to the rivet and the displacement of the punch. Thus, it can be seen that an accurate inspection can be performed on all the joint portions which are actually riveted, which means that the full inspection of the rivet joint can be performed most accurately. By applying the inspection method of the present invention as described above, it can be said that the produced product can have the highest reliability.

According to the present invention, it can be seen that the standard range of the load applied to the rivet and the displacement of the punch in the punch can be updated based on the data obtained as the work progresses. Therefore, the reliability of data including the standard range of load and punch can be further improved according to long-term use, which means that the reliability of the product to be produced can be continuously improved .

1 is an explanatory view for explaining the principle of a self-piercing rivet device;
Figure 2 is an exemplary illustration of a process by a self-piercing rivet device.
3 is a flow chart illustrating the method according to the present invention.
4 is a graph showing changes in load and displacement for one stroke.
5 is an exemplary block diagram showing a configuration for applying the control method of the present invention.
FIG. 6 is a cross-sectional view illustrating a state in which riveting is completed, in which (a) is a sectional view showing a normal state, and (b) is a sectional view showing an abnormal riveting state.

Hereinafter, the present invention will be described in more detail based on the embodiments shown in the drawings. FIG. 3 is a flowchart illustrating an exemplary inspection method according to an embodiment of the present invention, and FIG. 4 is a graph showing a load-displacement relationship obtained in a process in which normal riveting is completed. In the following description, the construction of the self-piercing rivet device itself will be described with reference to FIG.

As shown in FIG. 3, the inspection method of the present invention includes a step (S 110) of setting a standard range showing a normal relationship between a load and a displacement when two metal panels are normally riveted . In this specification, the term "load" refers to the force by which the punch 12 presses the rivet to the two panels Pa, Pb (S110). Such a load may be measured, for example, in a load cell installed in the anvil.

The term "displacement" means the distance that the punch 12 moves downward as the rivet joint proceeds, and a sensor for measuring the displacement of the punch 12 is provided in the self-piercing rivet device. Same as. It is a matter of course that the punch 12 connects the pair of panels Pa and Pb with rivets in a single stroke while performing a linear reciprocating motion within a set interval.

Here, the graph illustrated in FIG. 4 can be said to indicate how much load is applied substantially in accordance with the displacement of the punch 12 in one stroke (or cycle) in which normal riveting is performed . Therefore, it can be said that the 110th step (S110) substantially exemplifies how much the load range is preferable according to the displacement of the punch. With reference to the graph shown in FIG. 4, the meaning of each section or point in one process will be described with respect to a displacement of a punch and a change in a load with respect to one riveting process.

In Fig. 4, the horizontal axis represents the displacement (mm), and the vertical axis represents the load (Kg). As shown, the punch 12 is initially located at the top, with the punch 12 substantially in no contact with the panels Pa and Pb at this time. When riveting starts in this state, for example, the punch is moved downward by the hydraulic cylinder. After moving a certain distance downward, the rivet R will come into contact with the upper surface of the upper panel Pa, and this is the portion indicated by "A" in FIG.

The punch actually moves relatively quickly until the point A is reached, for example, at a speed of about 50-100 mm / sec. During the constant displacement after the point A, the rivet R is pressed into the upper panel Pa and the section passing through the upper panel proceeds. In this section, since the punch receives a certain repulsive force, the speed is relatively lowered and maintained at a speed of, for example, 10-30 mm / sec.

When the punch 12 passes through the upper panel Pa, the process of the section C is substantially progressed. In this section C, the load is temporarily lowered as the upper panel Pa penetrates, And the process of starting to rise again in the predetermined section is performed.

The section D continues to the section C so that the section D is formed by pushing the rivet R into the lower panel Pb and finally completing the process until the riveting is completed it means. In order to deform the rivet R so as to be completely fixed to the lower panel Pb in this process, a relatively large load is required in consideration of frictional force and the like, and since the displacement is relatively short, It can be seen that the section D has a steep slope.

The final point of the section D is indicated by a point D which is the moment when the rivet R causes the maximum deformation in the lower panel Pb, A point or point having a load value and a maximum displacement value. 6 (a) shows a state in which the rivet R passes through the upper panel Pa and is in a state of being deformed to the maximum in the lower panel And the above-mentioned point D means the point or point at which the rivet R is deformed to have such a state.

In addition, since the punch 12 has a rapid speed increase since the rivet fitting is substantially completed when the point E is completed, the load is lowered at a steep slope in the section F, . ≪ / RTI >

As described above, the relationship between the load-displacement in one stroke (riveting) in the self-piercing rivet device can be known. Step 110 of FIG. 3 refers to a process of obtaining a standard range of load and displacement of the punch in one scrub process in which normal riveting is completed as shown in FIG. These standard ranges include standard load ranges for angular displacement points of punches displaced while moving, standard displacement ranges at each point relative to the load applied by the punches, and standard slope ranges for the slope in section (D) And the standard maximum load and standard maximum displacement for the maximum load at point (E).

Here, the standard load range, the standard displacement range, the standard slope range, and the standard maximum load and standard maximum displacement are defined as a concept that includes an allowable tolerance range in which riveting operation can be performed in addition to a range of substantially desirable values I will use it. This standard range can be obtained, for example, by a number of tests. For example, a very large number of tests (for example, several hundred times) are performed on a pair of panels Pa and Pb, Can be determined based on the numerical value of the load-displacement seen at each point when a joint or a preferred riveting is performed.

For example, in FIG. 4, assuming that the load at the first position (m) is approximately 700 Kg, the standard displacement range corresponding to this load is in the range shown by the section bar at the first position (m) The range of 158 mm is the standard displacement range. The standard displacement range includes an allowable tolerance as described above.

And the displacement at point A is approximately 155 mm, and the load is approximately 400 kg. However, at point (A), at a specific displacement (for example 155 mm), the load may include a certain tolerance, so if it has a load of, for example, 350-450 Kg, it is normal and is referred to as the standard load range .

In addition, the standard displacement range is a value of 153 mm to 158 mm for a constant load (for example, 1000 Kg) at a specific point in the section (B). As described above, it can be judged that a normal rivet joint is performed when a load or a displacement within a certain range is taken into account in consideration of the allowable tolerance with respect to each displacement or load, and this will be referred to as a standard range. The standard slope described below also refers to a slope including an allowable tolerance and is a range in which normal riveting can be performed.

The standard range of the load or displacement obtained in the step 110 of superposition is stored in the storage unit 60 shown in Fig. Each of the measured values described below is a value measured by the sensor 70 including the load sensor and the displacement sensor, and this is transmitted to the control unit 50. The control unit 50 compares the measured value of the sensor 70 with a standard value (standard range) including the tolerance stored in the storage unit 60 and determines whether the value is normal or bad as described below .

The standard value stored in the storage unit 60 may be updatable using the accumulated data for a long period of time. Further, it is needless to say that the storage unit 60 may store the above-mentioned standard value, so that it is possible to use a memory mounted on the control unit. Here, the control unit 50 may be configured as a controller for controlling the entire self-piercing rivet device, or may be formed by a separate microprocessor.

It will be appreciated that the process of obtaining the standard value (standard range) can be obtained by a number of experiments as described above. However, such a standard range can be expected to be well known to those of ordinary skill in the art, in addition to being obtainable by actually testing panels and rivets, by accurate simulations. That is, based on the exact characteristics of the components of the self-piercing rivet device and the pair of panels and rivets.

If the standard range of the displacement and the load is obtained in step 110, the process 120 is performed to determine whether the standard range of the displacement and the load is normal by using the rivetting process in the actual production line. That is, in step 120 (S120), a first test is performed to determine whether the displacement or load corresponding to the load or displacement at an arbitrary point in the section B described above is within a predetermined range .

In the first test step, for example, the reference load value (actual load value) at an arbitrary first point m in the section B is judged as to whether or not the corresponding displacement value is within the standard displacement range do. And the first test step is a step of determining, for the reference displacement value (actual displacement value) at an arbitrary second point (n) within the interval (B), a load value corresponding thereto, It can be judged that it is within the range.

As described above, in the first test process shown in operation 120, the load value or the displacement value corresponding to the displacement value or the load value at a specific point in the section B, as described above, It is judged whether it is within the standard load range including the allowable tolerance or within the standard displacement range. Step 120 (first test procedure) is performed as follows: (1) it is determined whether the displacement for a predetermined load value at an arbitrary first position (m) is within a standard displacement range; (2) It is also possible to judge whether the load on the displacement value determined in the second position n is within the standard load range or (3) to separately perform the above-mentioned (1) and (2).

The section B described above is substantially a deformed section related to the panel Pa while the rivet R is press-fitted into the upper panel Pa. Accordingly, the section B may be referred to as a process in which the rivet R is press-fitted into the upper panel Pa. Also, since the section D shows a load-displacement in the process of pressing the rivet R substantially into the lower panel Pb, the section D may be referred to as a process in which the rivet presses the lower panel. If it is determined in step 120 that it is normal, the process 130 is performed. If it is determined that the process is defective, it is determined that there is a defect in the production line (S 160).

In operation 130, the second test is performed in the process of passing the section D, that is, the rivet R through the lower panel Pb. In the above-mentioned section D, the slope of the graph substantially progresses as described above. For the reason described above, it is a matter of course that there is a certain tolerance in the slope of the graph in the section D, and the inclination including the tolerance is defined as the standard slope range. Therefore, the second test performed in operation 130 is to determine whether the slope generated in the section D in the actual riveting process belongs to the standard slope range.

If the slope measured in step 130 is within the standard slope range, it is determined that the slope is normal. In step 140, the third test is performed. If the measured slope is out of the error range, it is determined that the slope is defective.

In operation 140, as described above, it is determined whether the highest load and the highest displacement occurring in one rivet joint process are within the standard maximum load range or the standard maximum displacement range stored in the storage unit. As can be seen from the graph of FIG. 4, since the range of the maximum load value and the maximum displacement value at the point (E) is already stored in the standard maximum range, during the actual riveting operation, It is judged whether or not the actual maximum load value and the displacement value measured within the range are within this range.

As described above, according to the present invention, the process of pressing the rivet into the upper panel Pa, the process of pushing the rivet into the lower panel Pb, and the load at the time when the pressing of the rivet is completed, It can be seen that the displacement is measured to determine whether the rivet joint performed by the self-piercing rivet device is normal or not.

When a plurality of test procedures as described above are performed, it is confirmed that not only the connection state of the pair of panels Pa and Pb but also the defect due to the invisible defect of the rivet itself can be sufficiently checked . For example, FIG. 6A illustrates a section of a state in which normal riveting is completed, and FIG. 6B illustrates an abnormal rivet, that is, a section of a rivet portion in a defective state.

Performing a test for load-displacement as described above will obviously check anything that results in the result shown in (b), such as the internal defects of the rivet itself, as described above, Pa, and Pb can be checked. That is, in a metallic material which causes small deformation in the riveting process, it is impossible for the load-displacement occurring in the normal process to fall within the standard range when any one is engaged. Even if it is a normal rivet, misalignment or the like in the process of setting the punch in front of the above-described punch can be sufficiently checked.

In the description of the above-described embodiments, the tests performed in accordance with the progression of the displacement of the punch have been sequentially described. However, it should be understood that various modifications may be made by those skilled in the art within the scope of the basic technical idea of the present invention, and that the present invention should be construed based on the scope of the appended claims.

Pa ..... upper panel
Pb ..... lower panel
R ..... Rivet

Claims (7)

A punch for pressing a rivet while reciprocating in a straight line in a predetermined section and an anvil provided so as to correspond to the punch with a pair of metallic panels Pa and Pb being an object to be bonded therebetween; to;
A data setting step of setting a standard range for the displacement and the load of the punch in one stroke process for riveting;
It is determined whether or not the corresponding load is included in the standard load range in at least one displacement position in the process of pressing the upper panel by the rivet or whether or not the displacement corresponding to the at least one load is included in the standard displacement range An upper panel judgment process; And
A lower panel judging step of judging whether or not a slope of a load with respect to a displacement is within a standard slope range in a process of press-fitting a lower panel by a rivet passing through the upper panel, Way.
A punch for pressing a rivet while linearly moving; and an anvil provided so as to correspond to the punch with a pair of metallic panels (Pa, Pb) being a joining object between the rivet and the joining object;
A data setting step of setting a standard range for the displacement and the load of the punch in one stroke process for riveting;
It is determined whether or not the corresponding load is included in the standard load range in at least one displacement position in the process of pressing the upper panel by the rivet or whether or not the displacement corresponding to the at least one load is included in the standard displacement range An upper panel judgment process; And
And a maximum displacement and load determining process for determining whether the rivet passing through the upper panel determines whether the maximum displacement and the maximum load at the maximum displacement point of the punch in the lower panel belong to the range of the standard maximum displacement and the standard maximum load Self-piercing rivet inspection method of riveting.
A punch for pressing a rivet while linearly moving; and an anvil provided so as to correspond to the punch with a pair of metallic panels (Pa, Pb) being a joining object between the rivet and the joining object;
A data setting step of setting a standard range for the displacement and the load of the punch in one stroke process for riveting;
A lower panel judging step of judging whether or not a slope of a load with respect to displacement is within a standard slope range when a rivet penetrating the upper panel presses the lower panel; And
And a maximum displacement and load determining process for determining whether the maximum displacement and the maximum load at the maximum displacement point of the punch belong to the range of the standard maximum displacement and the standard maximum load with the rivet being pressed into the lower panel as far as possible Self-piercing rivet inspection method of riveting.
The method of claim 1, further comprising, after the upper panel determination, determining whether a maximum displacement and a maximum load at a maximum displacement point of the rivet with respect to the lower panel belong to a range of a standard maximum displacement and a standard maximum load A method of inspecting a rivet of a self-piercing rivet device comprising:
4. The method according to any one of claims 1 to 3, wherein the data setting process comprises: a riveting operation of a self-piercing rivet device obtained based on a plurality of displacements of the punch and a plurality of load information measured when the rivet joint is normally performed method of inspection.
6. The method of claim 5, wherein the standard range set in the data setting step is an riveting operation of the self-piercing rivet device.
The method of claim 1 or 2, wherein the upper panel determination step comprises: determining whether the load corresponding to the displacement at the first position of the punch is included in the standard load range, Of the self-piercing rivet device is within a standard displacement range.

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