JPH04169828A - Method and apparatus for detecting riveting pressure of riveting machine - Google Patents

Abstract

PURPOSE:To make it possible to provide constant riveting force regardless of the length of a hose for connecting a pressure-oil supply source. which is different for each riveting machine, and the riveting machine by fixing a sensor which transmits an electric signal in proportion to the amount of strain to the yoke of the riveting machine. CONSTITUTION:A sensor 2 which converts the amount of mechanical strain into an electric signal in proportion to the amount of the strain and transmits the signal is fixed to a yoke 9 of a riveting machine 8. At the same time, a measuring device which measures the riveting force of the riveting machine 8 is mounted on the riveting machine 8. With the riveting pressure being measured with the measuring device, riveting is performed with the specified riveting pressure. Then, the magnitude of the signal outputted from the sensor 2 is stored in a memory device 4. The magnitude of the signal sent out of the sensor at the time of the riveting is compared with the magnitude of the stored signal in a judging device 2. When the magnitude from the sensor is larger than the magnitude of the stored 4 signal, OK is displayed. When the magnitude of the signal from the sensor 2 is smaller, NG is displayed. In this way, the riveting force can be made constant regardless of the length of a hose for connecting the supply source of pressure oil, which is different for every riveting machine, and the riveting machine.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a method and device for detecting the driving force of a fastener driving machine, and particularly to a method and device for automatically determining whether or not a fastener has been driven with a predetermined driving force for each fastener. and display the results to improve fastener driving performance.
The present invention relates to a method and device for detecting driving force of a fastener driving machine that can improve product reliability.

2. Description of the Related Art Conventionally, for example, when a main chassis frame of an automobile and a gusset are fastened together using a rivet, a round tapered rivet with a roughly hemispherical head is used to fasten the rivet with a snap attached to a riveting machine operated by pressure oil. Both ends of the round tapered head were pressed to form a cone shape and fastened.

The driving force at that time was controlled by the pressure of the pressure oil supplied to the fastener driving machine, but when the pressure oil flows through the hose that connects the pressure oil supply source and the fastening machine, the pressure increases due to pipe resistance. This has the disadvantage that the actual striking force decreases, and that it is difficult to statistically process the striking force to control quality since data on the striking force cannot be collected.

In addition, since the distance between the pressure oil supply source and the fastener driving machine differs for each fastener driving machine, the drop in driving force also differs depending on the fastening machine, making it difficult to manage and drive fasteners with a predetermined driving force. However, there was a drawback in that the hitting force varied from one hit to the next.

Furthermore, the appearance of the foot is not significantly different from the appearance of the head when the rivet is driven with a certain driving force, and it is impossible to judge the quality from the appearance alone. However, the drawback was that inspection was difficult and product performance varied.

As a method to eliminate the above-mentioned drawbacks, there is a method of attaching a driving force measuring device to the fastening machine and driving the fasteners while measuring the driving force, but this method not only requires an expensive measuring device but also is difficult to handle. The drawback is that it is difficult to use in actual situations.

Purpose The present invention has been made in order to eliminate the above-mentioned drawbacks of the prior art, and its purpose is to install a sensor that transmits an electrical signal proportional to the amount of mechanical strain on the yoke of a fastener driving machine. This makes it possible to maintain a constant driving force regardless of the length of the hose that connects the different pressure oil supply sources and the fastener setting machine to each fastener setting machine, and also makes it possible to The purpose is to make it possible to directly know the driving force when setting rivets.

Another purpose is to fix a sensor that sends out an electrical signal proportional to the amount of mechanical strain on the yoke of a fastener setting machine so that when a fastener is driven, the magnitude of the electrical signal sent out from the sensor is set to a predetermined value. To easily inspect whether each rivet can be hammered with a predetermined hammering force without requiring special attention by determining and displaying whether or not the size of the rivet has been reached. This also enables the fastening of rivets to be controlled not from the appearance but from the striking force, thereby eliminating variations in the striking force and improving the reliability of the product.

Still another purpose is to manage the fastener driving force directly as data, thereby statistically processing the driving force to perform quality control and improve product performance.

Configuration In short, the method of the present invention (claim 1) fixes a sensor that converts the amount of mechanical strain into an electrical signal proportional to the amount of strain and sends it out to the yoke of a fastener driving machine, and also adjusts the driving force of the fastening machine. A measuring device for measuring the driving force is attached to the fastener driving machine, and while the driving force is measured by the measuring device, the magnitude of the signal output from the sensor when driving a fastener with a predetermined driving force is stored in a storage device. and comparing the magnitude of a signal sent from the sensor when a fastener is driven with the magnitude of the stored signal to detect whether or not the fastener is driven with the predetermined driving force. It is something to do.

The device of the present invention (claim 2) also includes a sensor that is fixed to a yoke of a fastener driving machine and converts the amount of mechanical distortion of the yoke when driving a fastener into an electrical signal proportional to the amount of distortion, and sends the electrical signal;
A measuring device that is attached to the fastener driving machine and measures the driving force, and a storage device that stores the magnitude of the signal output from the sensor when a fastener is driven with a predetermined driving force while measuring the driving force with the measuring device. a determination device that determines whether the magnitude of the electrical signal sent from the sensor when a fastener is driven has reached the magnitude of the signal stored in the storage device; and a display device that displays the determined result. It is characterized by having the following.

The present invention will be explained below based on embodiments shown in the drawings. A driving force detection device 1 for a fastener driving machine according to the present invention is shown in FIGS.
In the figure, a sensor 2, a measuring device 3, a storage device 4,
It includes a discrimination value w5 and a display device 6.

The sensor 2 is for converting the amount of mechanical strain into an electrical signal and sending it out. Referring to FIGS. 1, 2, and 5, for example, a foil strain gauge 2 is an example of a sensor. is fixed to the yoke 9 of the fastener driving machine 8, and when the fastener is driven, the yoke is slightly bent by the driving force, and the foil strain gauge 2 is also slightly deformed along with the yoke 9, thereby changing its electrical resistance. However, this slight change in electrical resistance is converted into a change in voltage by the bridge box 10 and the dynamic strain meter 11, and the amount of mechanical strain on the yoke 9 is sent out as an electrical signal in proportion to the amount of strain. It has become.

Further, the riveting machine 8 is for pressing and fastening the rivet 12 in the vertical direction, and has a conical protrusion 13 on the lower surface 13a of the countersunk rivet snap 13 formed in the shape of a truncated cone.
b is formed.

The convex portion 13b has, for example, a diameter of 5 m at the base, an opening angle of 90 to 120° in a longitudinal section, and a rounded tip with a radius of about 2 mm. And snap for belly button 1
3 is fixed to a piston loft (not shown) of a hydraulic cylinder 14 fixed to one end 9a of the yoke 9 of the fastener driving machine 8, and operates in the vertical direction by supplying pressure oil to the flexible hose 15. ing. Also, the other end 9b of the yoke 9
A cone snap 16 is fixed opposite to the countersunk rivet snap 13. The cone snap 16 has a shape that intersects with the countersunk rivet snap 13, and the top surface 1
A cone-shaped recess 16b is formed in 6a.

The fastener driver 8 is equipped with a holding member 19 for suspending the fastener driver 8 by means of a bottle 18, and a switch 20 for operating the fastener driver 8.

Referring to FIGS. 3 and 4, the measuring device 3 is for accurately measuring the driving force of the fastener driving machine 8, and includes a measuring section 22.
, a dynamic strain meter 23, and a display 24.

The measuring unit 22 is a so-called load cell in which four electrical resistors 22a, which are precisely adjusted and which are attached to one end 9a of the yoke 9 of the fastener driving machine 8, are bridge-connected only when measuring the driving force. When strain occurs, the electrical resistance changes.

Depending on the magnitude of the striking force to be measured, the measuring section 22 is divided into, for example, a measuring section 22A for 25 tons and a measuring section 22B for 35 tons.
, 50 ton measuring section 22C, etc. are prepared, and an appropriate one is selected and used by connecting it to the dynamic strain meter 23.

The change in electrical resistance generated in the load cell is converted into a voltage change by the dynamic strain meter 23, and is displayed on a peak holder 24A or an oscilloscope 24B, which is an example of a display.

The storage device 4 is for storing the magnitude of the electrical signal sent from the sensor 2 when a fastener is driven with a predetermined driving force while measuring the driving force using the measuring instrument 3, and is for storing the magnitude of the electrical signal sent from the sensor 2. This is an electronic device electrically connected to 11.

The determination device 5 compares the magnitude of the electrical signal sent from the sensor 2 with the magnitude of the electrical signal stored in the storage device 4 to determine whether the magnitude of the stored electrical signal has been reached. It inputs signals from the storage device 4 and the dynamic strain meter 11, and outputs the result of comparing both signals to the display device 6.

The display device 6 displays OK (good) or NG (bad) according to the signal from the discriminating device 5, and is, for example, a known CRT (cathode ray tube) device. Further, the display device 6 may be a printing type storage device that stores the hitting force in numbers, or a magnetic storage device that converts it into magnetic data and stores it. Furthermore, the oscilloscope 6A may be used to display the signal from the dynamic strain meter 11 as a waveform.

The method of the present invention (claim 1) provides a sensor 2 that converts the amount of mechanical strain into an electrical signal proportional to the amount of strain and sends it out.
is fixed to the yoke 9 of the fastener driving machine 8, and a measuring device 3 for measuring the driving force of the fastening machine 8 is attached to the fastening machine 8.
While measuring the driving force, the magnitude of the signal output from the sensor 2 when driving a fastener with a predetermined driving force is stored in the storage device 4, and the magnitude of the signal output from the sensor 2 when driving a fastener is compared to This method compares the magnitude of the stored signal to detect whether or not the fastener has been driven with a predetermined driving force.

Function The present invention is constructed as described above, and its function will be explained below. In FIGS. 1, 2, and 3, the measurement unit 22 is attached to the fastener driving machine 8, and while measuring the driving force with the display 24A or the oscilloscope 24B, the pressure is supplied from a pressure oil source (not shown). The oil is supplied to the hydraulic cylinder 14 while adjusting the pressure, and the fasteners are driven with a predetermined driving force, for example, 50 tons, and the output signal of the sensor 2 is stored in the storage device 4 (at this time, the dynamic strain is By calibrating the output value of the total 11 and the output value of the measuring device 3, the hitting force can also be known as a numerical value.

Next, after removing the measuring part 22 from the fastener driving machine 8, the main chassis frame 23 and the gusset 24 are fastened together by driving fasteners with rivets 12, but the output from the sensor 2 during fastening is stored in the discriminator 5. It is compared with the magnitude of the signal stored in the device 4, and if the magnitude is greater than the magnitude of the cough memorized signal, it is OK, and if it is smaller than the magnitude of the signal, it is NG.
is displayed on the display W6, so it can be immediately determined whether or not the fastener has been driven with a predetermined correct driving force.

As mentioned above, it is possible to easily determine whether or not the hitting force is appropriate using the measuring device 3 that is difficult to handle. You only need to do this when replacing sensor 2.
It's not bothersome.

In the above embodiments, the display device was described as one that displays whether the hitting force is good or bad, but the display device is not limited to displaying whether the hitting force is good or bad, and may display the hitting force in numbers, Alternatively, it may be something that is recorded. Furthermore, the output signal of the dynamic strain meter 11 can be connected to a counter to count the number of rivets driven to prevent forgetting to drive a rivet, or can be fed to a pressure oil supply device to control the pressure of pressure oil. It may be controlled to automatically obtain a predetermined hitting force.

Effects As described above, the present invention has a sensor that sends an electric signal proportional to the amount of mechanical strain fixed to the yoke of the fastener driving machine, so that each fastener driving machine has a different pressure oil supply source and a different fastener driving machine. This has the advantage that the driving force can be kept constant regardless of the length of the hose connecting to the machine, and that the driving force when actually driving a fastener can be directly known.

Furthermore, when a sensor that sends out an electrical signal proportional to the amount of mechanical strain is fixed to the yoke of a fastener driving machine and a fastener is driven, the electrical signal sent out from the sensor reaches a predetermined size. Since it is possible to determine and display whether or not the rivet has been hammered, it is possible to easily and without requiring special attention check whether or not each rivet can be hammered with the specified hammering force. This has the effect of making it possible to manage fastening based on the striking force rather than looking at the appearance, thereby eliminating variations in the striking force and improving the reliability of the product.

Furthermore, since the fastener driving force can be directly managed as data, it is possible to statistically process the driving force to perform quality control and improve product performance.

[Brief explanation of the drawing]

The drawings relate to embodiments of the present invention; FIG. 1 is a perspective view showing the entire fastener driving machine equipped with a driving force detection device, FIG. 2 is a front view of the same, and FIG. FIG. 4 is a block diagram showing the configuration of the measuring device, and FIG. 5 is a block diagram showing the configuration of the striking force detection device. 1 is a driving force detection device, 2 is a sensor, 3 is a measuring device, 4 is a storage device, 5 is a discrimination device, 6 is a display device, 8 is a fastener driving machine, 9
is a yoke.

Claims (1)

[Scope of Claims] 1. A measuring device in which a sensor that converts the amount of mechanical strain into an electrical signal proportional to the amount of strain and sends it out is fixed to the yoke of a fastener driving machine, and measures the driving force of the fastener driving machine. is attached to the fastener driving machine, the driving force is measured by the measuring device, and the magnitude of the signal output from the sensor is stored in a storage device when a fastener is driven with a predetermined driving force. A fastener driving machine, characterized in that it detects whether or not the fastener has been driven with the predetermined driving force by comparing the magnitude of a signal sent from the sensor when a fastener is driven with the magnitude of the stored signal. Hitting force detection method. 2. A sensor fixed to the yoke of the fastener driving machine to convert the amount of mechanical distortion of the yoke when a fastener is driven into an electrical signal proportional to the distortion and send it out; A measuring device for measuring, a storage device for storing the magnitude of a signal outputted from the sensor when a fastener is driven with a predetermined driving force while measuring the driving force with the measuring device, and a signal sent from the sensor when a fastener is driven. The device is characterized in that it is equipped with a discriminating device for discriminating whether the magnitude of the electric signal reached the magnitude of the signal stored in the storage device, and a display device for displaying the determined result. A driving force detection device for a riveting machine.