JPS6071932A - Piston cup inspecting machine - Google Patents

Abstract

PURPOSE:To discriminate accurately whether an outer lip part easy to crack is defective or not by pressing an inspecting jig to the inside of the outer lip of a piston cup and impressing an inspecting pressure and detecting variation of the inspecting pressure. CONSTITUTION:When a piston cup 1 is placed in a fixed position just under an inspecting jig 10, a hydraulic cylinder is operated, and the inspecting jig 10 falls and has the tip fitted to an annular recessed part 1c of the piston cup 1. At this time, an outer lip 1d of the piston cup 1 is brought closely into contact with the taper outside circumferential part of the inspecting jig, and the annular tip part of the inspecting jig 10 is brought closely into contact with the inside of the annular recessed part 1c. Next, the inspecting pressure is impressed to the inside of the outer lip 1d of the piston cup 1 from an inspecting pressure source through a nozzle hole 12. The inspecting operation is started several seconds after, and the inspecting pressure in the piston cup 1 is detected by a pressure sensor to inspect whether the outer lip 1d is cracked or not.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piston cup inspection machine for inspecting the sealing performance of a piston cup used in a master cylinder of an automobile brake system or the like.

As shown in FIG. 1, the conventional piston cup inspection machine includes an inspection table 2 which is hollow and has a hole in the center for holding the cup l, and an outer lip peripheral edge 1 of the cup l on the inspection table 2.
The center hole 3a of the pressing part 3 is provided with a pressing part 3 for pressing a.
Pressure air is applied to the upper part of the cup 1 from the cup 1, and the air leaking into the examination table 2 through the cup 1 is introduced into the water tank 5 through the pipe 4, and the presence or absence of bubbles generated in the water tank 5 is detected using an optical sensor, etc. However, since the holding jig of this type of piston cup inspection machine presses the outer lip periphery 1a of the cup 1, the cracks created in this area are compressed and held. There was a problem in that the product was judged to be good even though it had a crack, and it was not possible to detect the flaws from the outer lip periphery to the inside, which accounted for most of the defective products.

This invention focuses on the above points, and aims to provide a piston cup inspection machine that can accurately detect cracks from the outer lip periphery to the inner side of a piston cup, and for this purpose,
An inspection jig having a nozzle hole whose tip is inserted into a piston cup and applies pressurized air to the outer lip of the cup; an inspection pressure source that supplies pressurized air at a predetermined inspection pressure to the inspection jig; A pressure sensor detects the air pressure applied to the inspection jig from a pressure source and outputs a voltage signal according to the pressure, and the detection data of the air pressure detected by the pressure sensor is compared with the set value, and the comparison result is The system is equipped with an inspection circuit that determines the quality of the piston cup based on the above.

Embodiments of the present invention will be described below based on the drawings.

FIG. 2 shows a cross-sectional view of the inspection jig 10 that is fitted into the piston cup 1. The inspection jig 10 has a bullet-shaped main body with a cutout with the center of the tip aligned with the central protrusion 1b of the piston cup 1.
The ring-shaped notch tip is formed so that it can be fitted into the annular recess 1c of the piston cup 1, and an air passage 11 is formed inside the bullet-shaped body, and as shown in FIG. It communicates with a plurality of nozzle holes 12 provided on the outer periphery of the tip of the inspection jig IO. The air passage 11 is connected to a suction pipe 13 and a pipe 13 for supplying test pressure, which will be described later, at the outer peripheral portion of the test jig IO.

FIG. 4 shows a schematic configuration diagram of a piston cup inspection machine, in which the inspection jig 10 is attached to the tip of a piston rod of a fluid pressure cylinder 15 attached to the tip of a transfer arm 14, and is movable up and down. . 16 is a suction pump, and a solenoid valve 17
It is connected to the pipe 13 via the pipe. 18 is an inspection pressure source that supplies a predetermined inspection pressure, for example 0.3 kg/c
It is constituted by an air pump device etc. that supplies low pressure air of about m', and is connected to piping 13 via solenoid valves 19 and 20 connected in series. A pressure sensor 21 is attached to a pipe between electromagnetic valves 19 and 20, which detects the air pressure within this pipe and outputs an analog voltage signal corresponding to the detected pressure. 22 is an amplifier for amplifying the pressure detection signal output from the pressure sensor 21; 23 is for comparing the level of the amplified pressure detection signal output from the amplifier 22 with a preset value corresponding to the lower limit pressure for a non-defective product. The comparator outputs a high level signal when the detected signal level is above a set value, that is, when the product is good. Reference numeral 24 denotes a determination circuit that inputs the signal output from the comparator 23 and determines the test result based on the signal. A logical OR with the output signal is taken, and if this is a high level, a non-defective signal is output. 2
5 is a control circuit that performs sequence control of the entire inspection machine;
Upon receiving the non-defective product signal sent from the determination circuit 24, a control operation is started to send the piston cup 1 after the inspection to the next cutting process. On the other hand, if the non-defective product signal is not input within a predetermined time, the subsequent control operations are stopped and an alarm is issued to notify the occurrence of a defective product. The amplifier 22, comparator 23, and determination circuit 24 constitute a test circuit.

Next, the operation of the piston cup inspection machine will be explained.

When the piston cup l is placed in a fixed position directly below the inspection jig lO, the fluid pressure cylinder 15 is activated and the inspection jig lO
is lowered, and the tip of the inspection jig 10 is fitted into the annular recess 1c of the piston cup 1, as shown in FIG. At this time, the outer lip ld of the piston cup 1 is in close contact with the tapered outer periphery 5- of the inspection jig lO, and the ring-shaped tip of the inspection jig lO is in contact with the annular four part 1.
Closely attached to inside c.

Next, the solenoid valves 19 and 20 are opened (the solenoid valve 17 is closed), and a relatively weak test pressure of, for example, about 0.3 kg/cm'' is applied from the test pressure source 18 through the pipe 13, air passage 11, and nozzle hole 12. Outer lip ld of piston cup l
is applied inside. After that, for example, after a few seconds, the solenoid valve 2
0 is closed and a test operation in the test circuit is started. Incidentally, FIG. 5 shows temporal changes in the test pressure detected by the pressure sensor 21, and shows time 1. When the test pressure is applied,
Time t2 is the time when the test starts when the solenoid valve 20 is closed. The test pressure applied within the piston cup l is detected by the pressure sensor 21, and an analog voltage signal corresponding to the pressure is sent to the comparator 23 via the amplifier 22. For example 0.27
kg/ctn". In this state, in synchronization with a timing signal generated at time t2, that is, 1.3 seconds after the start of the test, the piston cup is In other words, when the outer lip ld of the piston cup 1 is good without any cracks, the detected pressure is approximately 0.3 kg/cr.
When the signal level input to the comparator 23 exceeds the set value, a high level signal is sent to the determination circuit 24, and the determination circuit 24 checks the input signal level at time tl. If the level is high, the control circuit 2 will output a good product signal.
Output to 5. When a good product signal is input to the control circuit 25, the solenoid valve 19 is first closed, the solenoid valve 17 is opened, and the suction pump 16 changes the piston cup l into a negative pressure state, and the piston cup l is moved to the inspection jig lO. Attach to the tip of the In this state, the fluid pressure cylinder 15 operates to lift the inspection jig 10, and the transport arm 14 is operated to carry the piston cup l adsorbed to the inspection jig lO to a predetermined location. Return to the original position and perform the inspection.

On the other hand, when a defective product with a crack in the outer lip ld of the piston cup 1 is inspected, the pressure detected by the pressure sensor 21 decreases from inspection start time t2 due to air leakage, as shown by the broken line in FIG. 5. Therefore, at the time of inspection at time t3,
The signal level entering the comparator 23 will be below its set value, and
A low level signal is sent from the comparator 23 to the determination circuit 24, and the determination circuit 24 determines that the product is defective, and the control circuit 2
No good product signal is sent to the piston cup 5, the subsequent transport operation of the piston cup 1 is stopped, and at the same time, a warning for detecting a defective product is issued by a lamp or a buzzer.

As explained above, according to the piston cup inspection machine of the present invention, the inspection jig is pressed against the inside of the outer lip of the piston cup to apply inspection pressure, and pass/fail is determined based on the change in the inspection pressure. Compared to conventional equipment that compresses and holds the outer lip for inspection, it is possible to accurately and quickly determine the acceptability of the outer lip, where cracks tend to occur, and the inspection time is short, making it easier to transport the piston cup after inspection. This makes it possible to completely automate the inspection process and improve inspection efficiency.

[Brief explanation of drawings]

Fig. 1 is a main sectional view of a conventional inspection machine, Fig. 2 is a sectional view of an inspection jig in an inspection machine showing an embodiment of the present invention, Fig. 3 is a sectional view taken along line A-A in Fig. The figure is a schematic configuration diagram of the inspection machine, and FIG. 5 is a graph showing changes in inspection pressure. 1... Piston cup, ld... Outer lip, lO.
... Inspection jig, 12... Nozzle hole, 18... Inspection pressure source, 21... Pressure sensor, 22... Amplifier, 23
... Comparator, 24... Judgment circuit. Patent application Toyoda Gosei Co., Ltd.-9= Figure 1 Figure 2

Claims (1)

[Claims] an inspection jig having a nozzle hole whose tip is inserted into a piston cup and applies pressurized air to the outer lip of the cup; an inspection pressure source that supplies pressurized air at a predetermined inspection pressure to the inspection jig; A pressure sensor detects the air pressure applied to the inspection jig from the inspection pressure source and outputs a voltage signal according to the pressure, and the detection data of the air pressure detected by the pressure sensor is compared with a set value. A piston cup inspection machine comprising: an inspection circuit that determines the quality of a piston cup based on a comparison result.