JPS6350115B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention abuts the joined parts of joined members against each other, rubs them against each other, melts the joined parts, and then stops the frictional movement and cools and solidifies the fused parts. The present invention relates to a method and apparatus for determining the quality of joined products by so-called friction welding, in which joined members are joined together.

(Conventional technology) Conventionally, as for friction welding,
Publication No. 41-21125, Japanese Patent Publication No. 44-28984, etc. are disclosed.

(Problems to be Solved by the Invention) Friction welding has high joining performance and excellent productivity, so it is widely used for joining metals and plastics.

In addition, various relationships among friction conditions such as friction pressure, friction speed, and time required for friction have been conventionally determined in order to improve the joining performance of welded products.

It has been thought that it is possible to completely control these frictional speeds, pressures, etc. to a certain extent, and that it is possible to maintain a constant bonding strength of welded products by controlling them to ideal conditions.

However, even with well-scrutinized joining conditions, so-called defective products with low joining strength often occur.Furthermore, conventionally, the joining performance of friction-welded products could only be confirmed through destructive testing.
There was a problem that complete quality assurance was not possible.

Therefore, in the past, a welding device with higher precision was used to obtain a bonding strength commensurate with the condition setting, and by selecting welding conditions with sufficient margin, the production of defective products was avoided.

It would be particularly desirable if a pass/fail judgment method or a pass/fail judgment device capable of determining the quality of a joined product during welding work could be realized, since it would be possible to significantly improve the reliability of welding without the need for inspection.

(Means for Solving the Problems) Therefore, in view of the above problems, the present inventors,
As a result of various experiments and research, as well as intensive consideration, we have found that under conventional welding conditions, the time required from the time the frictional motion, which was completely unmarked, starts to stop until it comes to a stop is a major factor. I discovered that.

The present invention has been made based on this discovery, and in order to meet the above-mentioned needs, it is an object of the present invention to provide a method and apparatus that can reliably determine the quality of a joined product during welding work.

That is, in a welding method in which the joined parts of joined members are butted against each other, rubbed against each other, the joined parts are melted, the frictional motion is stopped, the fused parts are cooled and solidified, and the joined members are joined. Perform welding based on the conditions, determine the relationship between the time from when the frictional motion starts to stop until it stops, and the bonding strength, and from this relationship, predetermine a reference value corresponding to the required bonding strength, During friction welding, the time from the time the frictional motion starts to stop until it stops is measured, and if the value is greater than the above standard value, the joined product is judged as defective. In a device that butts together the joints of and frictionally joins them,
A means for measuring the time from when the friction motion starts to stopping until it ends, and a means for displaying the measured value, or a means for comparing the measured value with a preset reference value to indicate whether the joined product is good or bad. Alternatively, there is provided a device for determining the quality of jointed products by friction welding, characterized in that it has a means for sorting the joined products into good and defective products.

(Effects of the Invention) According to the present invention, it is possible to determine the quality of a joined product by checking the time from when frictional motion, which has not been marked at all in the past, starts to stop until it ends.

Therefore, it is possible to determine whether the joint is good or bad during the welding process, which was previously impossible, so the quality of the joined product can be easily improved, and costs can be reduced by eliminating the inspection process. It has the following characteristics.

(Example) The embodiments shown in the drawings will be described below.

FIG. 1 is a basic configuration diagram of a conventionally known friction welding device.

In FIG. 1, 7a and 7b are joining members,
Each is held by jigs 6a and 6b. The gripping tool 6a on the driving side is fixed to the main shaft 4, and is driven by the motor 1 through the brake 3 and the clutch 2, and is moved by the arrow 5.
It is designed to rotate in the direction of.

On the other hand, the gripper 6b on the fixed side does not rotate, but is pressurized by the cylinder 8 in the direction of the arrow 9.

In such a welding device, the joining members 7a, 7b
are rotated relative to each other while pressurizing each other, and after the joint surfaces are rubbed against each other and melted, the frictional movement is stopped by the brake 3, and the molten part is cooled and solidified to perform friction welding.

FIG. 2 is a basic configuration diagram of another conventionally known type of friction welding device.

In FIG. 2, 17a and 17b are joining members, and 16a and 16b are jigs for gripping the joining members. The jig 16b on the pressurizing side is the cylinder 18
This allows pressure to be applied in the direction of arrow 19.

The jig 16a on the moving side is connected to the eccentric portion 14a of the rotating shaft 14 via the bearing 10,
Further, rotation is restrained by a restraint device 20.

The rotating shaft 14 is connected to a motor 11 via a brake 13 and a clutch 12, and can be rotated by the motor 11 as shown by an arrow 15.

FIG. 3 shows the jig 16a and rotating shaft 1 of the device shown in FIG.
The engagement relationship with 4 is shown in detail.

When the rotating shaft 14 is rotated in such a combination, like the jig 16a, it moves in a circular orbit having a radius equal to the distance r between the center _O0 of the rotating shaft 14 and the center _O1 of the rotating shaft 14a.

That is, the joining members 17a and 17b perform a frictional motion relative to each other in a circular orbit.

In addition, in the device shown in FIG. 2, if the hole 21 of the jig 16a circumscribing the bearing 10 is made into an elongated hole as shown in FIG. This is a reciprocating motion that strokes.

As described above, there are several types of friction welding devices depending on the type of frictional motion, but all of them have the drawback that it is not possible to determine the quality of the welded products during the welding process.

The present invention provides a method and apparatus that can determine the quality of the joint during the welding process in friction welding using various motion forms.

Conventionally, it was thought that there was no good inspection method other than destructive inspection for production control of friction welding.

Therefore, conventionally, defective products have been prevented by using a welding device with high accuracy in setting conditions and by selecting welding conditions with sufficient margin.

It was thought that conventional welding conditions such as friction speed, friction pressure, and friction time could be managed with this management method, but even if welded under carefully-scrutinized welding conditions, defective products may still be produced. Sometimes it comes out.

After intensively investigating this point, we discovered that the stopping time of frictional motion, which had previously been completely unmarked, was a major factor.

The graph in FIG. 5 schematically shows the change in friction speed during welding, with time on the horizontal axis and friction speed on the vertical axis. In FIG. 5, V ₁ is the portion where the velocity increases at the beginning of the movement. V ₂ is a constantly moving part with stable velocity.

The stop time of frictional motion is the point at which the motion is completed from the _point at which the frictional motion begins to decrease at the end of welding.
The time corresponding to the period V ₂ up to V ₀ is the stop time t _s of the frictional motion. As a result of examining various examples of t _s (hereinafter referred to as stop time), it became clear that there is an extremely close relationship with bonding performance.

Figures 6 and 7 are examples. FIG. 6 shows an example in which nylon resin is bonded using the method shown in FIG. 1, and FIG. 7 shows an example in which polyacetal resin is bonded using the method shown in FIGS. 2 and 3.

Looking at Figures 6 and 7, it can be seen that in both cases, the longer t _s becomes, the lower the bonding strength becomes.

However, the _ts at which good welding performance can be obtained is usually an extremely short time of 0.1 seconds or less. It is difficult to manage absolute values with good reproducibility.

In particular, in ordinary welding equipment that is stopped by a brake or a clutch, the condition of the friction plate constantly changes due to external disturbances and wear, so t _s actually varies considerably.

As a result of various studies, we found that setting the conditions was insufficient, and in the end, the most effective method was to actually measure the time required to stop each time we welded, and then judge whether the joined products were good or bad based on the measured value. Turns out it's legal.

Therefore, we first perform welding several times under various conditions for friction welding, and then examine the strength of the welded product to determine the relationship between the time from when the frictional motion begins to stop until it stops and the joint strength. death,
Based on this relationship, a standard value corresponding to the required joint strength is determined in advance, and when performing friction welding, the time from the time the frictional movement starts to stopping until it stops is determined, and the value is determined to be higher than the above standard value. If it is large, the bonded product is determined to be defective.

Of course, the critical time that serves as a standard for determining pass/fail differs depending on the joining members, joining conditions, required performance of the joined product, etc. Naturally, a product with t _s smaller than the standard value is a passed product, and a larger t s is a rejected product.

Furthermore, which of A, B, or C in FIG. 7 should be used as the standard depends on the technical level and the nature of the product.

In addition, good products and defective products are handled differently, with defective products sometimes being discarded or even subjected to strict inspection.

As described above, the present invention measures the stopping time of the frictional motion and compares it with a predetermined time to determine whether it is good or bad, and has the effect of being able to determine whether the joined products are good or bad at the time of welding.

8 to 10 relate to an example of an apparatus for implementing the method of the present invention.

A conventionally known friction welding device as shown in Figs. 1 and 2 is equipped with a means for measuring the time from when the friction motion starts to stopping until it stops, and the measured time is displayed or the measured time is displayed. This is a determination device that compares it with a preset reference time and displays whether it is good or bad.

The means for measuring the required stopping time can be achieved by generally known measurements of rotational speed, time, etc., and processing of these data.

For example, the rotation of the shaft 4 or 14 is measured using a mechanical, electromagnetic or pulse count type tachometer, the _Vs point is detected by successive comparison or differentiation of the measured values, and a timer is started. Then, by stopping the timer when the shaft rotation reaches zero, the required stopping time _ts can be determined.

There are several methods for processing the required stop time value obtained in this way. The simplest method is to display the required stop time itself.

If the operator is aware of the standard values for determining pass/fail in advance, he or she can judge whether or not the joining was successful. Furthermore, set a standard value,
If the measured value is large based on this, it is "defective".
If it is smaller, it may be displayed as "good".

Furthermore, if the machine is an automatic machine, the bonded products may be automatically sorted into good and defective products based on a reference value. This automatic sorting device will be described later.

In a friction welding device in which frictional motion is generated by rotation of a rotary shaft, the required stopping time can be configured with a simpler device.

In FIGS. 8 to 10, 4 is a rotating shaft, and 4' is a frame of a stop time measuring device fixed to the rotating shaft. 32 is a leaf spring, and the inertial body 31 is movably fixed to the rotating shaft 4.

S ₁ and S ₂ are electrical switches, which close the circuit when the inertial body 31 comes into contact with them, and open the circuit when they separate.

With such a device, if the strength of the leaf spring, the mass of the inertial body, and the positions of electrical switches S ₁ and S ₂ are adjusted appropriately, the rotating shaft will stop when the rotation direction is indicated by arrow 5. When the inertial body is being accelerated or rotating at a constant speed, the inertial body is kept in the position shown in Figure 8, and _S2 and the inertial body come into contact, closing the electric circuit of _S2 ,
When the electric circuit of S ₁ is opened and stop acceleration is applied, that is, when the speed decreases, the spring 32 is deflected by the inertia force as shown in FIG. 9, S ₁ is closed, and S ₂ is opened.

S ₁ and S ₂ of such a device constitute a circuit as shown in FIG. 10. In Figure 10, DC is a constant voltage power supply, C is a capacitor, is a voltmeter, and R
is resistance.

With such a device, when the welding device is stopped, accelerated, or operating at a constant speed, that is, in the state shown in Figure 8,
Figure 10 S ₂ is closed and the capacitor is connected to the power supply.
Charge is stored by DC, and eventually the voltage becomes the same as the power supply.

On the other hand, when the welding equipment is stopped and a stop acceleration is applied to the rotating shaft, the stop time measuring device of this example becomes as shown in Fig. 9, and since S ₂ opens and S ₁ closes, as shown in Fig. 10. In this circuit, the charge stored in the capacitor is discharged and the voltage drops. Naturally, the voltage drop occurs when switch _S1 is closed,
In other words, the time during which stopping acceleration is applied to axis 4
t is proportional to _s . Therefore, by reading the voltage of the capacitor with a voltmeter, the required stopping time _ts can be determined.

In this example, the displacement of the inertial body was detected using a contact type switch, but the required stop time can be similarly measured using a non-contact type proximity switch such as an electromagnetic type or a photoelectric type.

Next, an example of an automatic sorting device will be described.

In the bonding apparatus shown in FIG. 11, a hole 51 is provided in the base 50 below the gripper 6. The hole 51 is provided with a two-way chute 52 having a switching damper 53.

The damper 53 rotates around the shaft 54 and assumes a position 53a indicated by a solid line and a position 53b indicated by a dotted line. When the damper 53 is not in operation, the spring 5
7, the tank takes the position 53a indicated by the solid line, so the tank A side of the chute is open.

A spring 5 is connected to the shaft 54 via an electromagnetic clutch 55.
It is connected to a constant torque motor 56 whose rotational direction is opposite to the operating direction of 7.

The electromagnetic clutch 55 is connected to X in FIG. 10 through point X of the circuit as shown in FIG.

In Figure 13, AMP is an amplifier, R is a variable resistor,
Tr is a triax, DC is a direct current power supply, K is an electromagnetic clutch 55, and Ti is a timer.

When the variable resistor R is adjusted with such a device, when the required stop time exceeds a predetermined time (set by R), the triac Tr is activated, the electromagnetic clutch 55 is activated, and the damper 53 is activated by the motor 56. 57 and rotates to the dotted line position 53b.
It will take the position of

Therefore, the tank B side of the chute 52 is opened only for the time preset by the timer Ti. Therefore, the joined products that have been removed from the grip after joining fall into the hole 51, pass through the chute 52, and are sorted into tank B, which is a stock of defective products.

If the product is normal, the voltage of X does not reach the trigger voltage of the tri-ac Tr, so the tank A side of the chute 52 is open, and the product is sorted into the tank A of non-defective products.

The above is an example of an automatic sorting device, and it goes without saying that any other automatic sorting device can be employed.

In the embodiment, an example of plastic is shown, but the present invention can be similarly applied to welding of metal.

As explained in detail above, if the present invention is carried out, it is possible to determine the quality of the joint in the welding process, which was previously impossible, so the quality of the joined product can be easily improved, and the inspection process can be eliminated. This makes it possible to reduce costs.

[Brief explanation of the drawing]

Figure 1 shows an example of a conventionally known friction welding device.
Figure 2 shows another example of a conventionally known friction welding device. FIG. 3 is a detailed view of the joint between the rotating shaft and the joining jig of the friction welding device shown in FIG. 2. FIG. 4 is an explanatory diagram of yet another friction welding device, and FIG.
The X′ plane is shown. FIG. 5 is a graph showing changes in friction speed over time in a friction welding device. Figure 6,
FIG. 7 is a graph showing the relationship between the required stopping time _ts and the bonding strength. FIG. 8 and FIG. 9 are diagrams showing the main parts of the stop time measuring device of the present invention, and show a cross section perpendicular to the axis of the rotating shaft. FIG. 10 shows an example of the electric circuit of the stop time measuring device of the present invention. FIGS. 11 and 12 are cross-sectional and oblique views of the automatic sorting device of the present invention. FIG. 13 shows an example of the electric circuit of the automatic sorting device. 4... Rotation axis, 4'... Frame, 31... Inertial body,
32... Leaf spring, S ₁ , S ₂ ... Switch, DC... Direct current power supply, V... Voltmeter, C... Capacitor, R... Resistor.

Claims (1)

[Claims] 1. In a welding method in which the joined parts of joined members are butted against each other, rubbed against each other, the joined parts are melted, the frictional motion is stopped, and the fused parts are cooled and solidified to join the joined members. Perform welding under various welding conditions, determine the relationship between the time from when the frictional motion starts to stop until it stops, and the joint strength, and use this relationship to determine the standard value corresponding to the required joint strength. Measure the time from when the friction motion starts to stop until it stops during friction welding, and if the value is greater than the above standard value,
A method for determining the quality of jointed products using friction welding, in which the joined products are considered defective. 2. In a device that butts the joint parts of joining members and causes them to rub against each other and join, there is a means for measuring the time from when the frictional motion starts to stopping until it ends, and a means for displaying the measured value, or a means for displaying the measured value and a preset value. Compare with the standard value to determine whether the bonded product is good or not.
1. A device for determining the quality of jointed products made by friction welding, characterized by having means for displaying defects or for sorting joined products into good and defective products. 3 In claim 2, the frictional motion is generated by a rotating shaft, and a mass body that can move in the rotational circumferential direction is disposed on the rotating shaft, and the relative stop delay of the mass body due to stopping acceleration is A device for determining the quality of jointed products made by friction welding, which measures the time required for frictional motion to stop by detecting 4. A device for determining the quality of a jointed product by friction welding according to claim 3, wherein the relative stop delay of the mass body is detected by an electric switch operated depending on the position of the mass body. 5. A device for determining the quality of a jointed product by friction welding according to claim 3, wherein the relative stop delay of the mass body is detected by a non-contact switch.