JPS6318789B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for detecting a shortage of parts in an object to be inspected, such as a shortage of rolling elements in full roller bearings, some roller bearings with cages, full spherical bearings, etc. It is.

Conventionally, as a means of detecting the shortage of rolling elements in a bearing as described above, a weight sorter is used.
Bearings with a normal number of rolling elements and bearings with an insufficient number of rolling elements can be sorted by comparing their weights, or
As shown in the figure, with the rolling elements 30 inserted between the outer ring 10 and the shaft 20 of the bearing, a specified number of rolling elements 30
In order to detect whether or not the shaft is charged, a notch 40 is provided in the shaft, and a slider 50 is provided in the notch 40 so as to protrude outward (in the radial direction) in a free state. , the state in which the slider 50 protrudes outward (in the radial direction) can be detected by a micro switch, and when the specified number of rolling elements 30 are inserted and there is almost no gap, the above-mentioned sliding The slider 50 does not protrude outward, but if the specified number of rolling elements 30 are not loaded, the slider 50 will close the gap between the rolling elements 30 (a gap larger than one rolling element). ), and this protrusion was detected by the microswitch, and it was possible to detect that the specified number of rolling elements 30 were not inserted.

However, when detecting a parts shortage using the above method, in the former case, if the rolling elements are small and light, the difference in weight between the normal case and the case of a shortage of rolling elements is small, making it difficult to detect a parts shortage. There were times when it was difficult.

In the latter case, if the slider becomes worn out due to long-term detection work, it is necessary to replace it with a new slider to eliminate detection errors. Even if a gap occurs due to a lack of rolling elements, if the rolling elements continue to tilt as shown in Figure 3, the gap will disappear, the slider will not protrude, and the lack of rolling elements will not be detectable. There were other drawbacks.

This invention was made in order to eliminate the above-mentioned drawbacks, and uses an eddy current to detect the distance between metal objects near the parts of an object to be inspected placed on a rotating support. A detection coil is provided,
The presence or absence of a component in the object to be inspected that moves with the rotational displacement of the rotary support is detected in a non-contact manner, and a detection signal based on the presence or absence of the component is measured during two or more rotations of the rotary support. This is a device that detects a shortage of parts in an object to be inspected by comparing the number of parts of the object to be inspected with a preset number.

Next, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a full-complement rolling bearing is selected as the object to be inspected, and a device for detecting the lack of rolling elements is shown. 1 is a detection coil for detecting the rolling elements of the above-mentioned rolling bearing, and 2 is the above-mentioned detection coil. This is a high frequency oscillation circuit in which a detection coil 1 is configured as the L component of an LC oscillation circuit.A detection circuit 3 that detects an amplitude modulated output is connected to this high frequency circuit 2.
is connected to an AC amplifier 4 for amplifying the voltage, and is further provided with a comparator 5 for converting the analog signal from the AC amplifier into a digital signal for input to the AND circuit 10 described below. . 6 is a proximity switch, which is arranged near the circumferential surface of the rotary support 13 described below, and detects a slit 14 provided in a part of the circumferential surface of the rotary support 13;
One pulse signal is obtained for each rotation of the rotary support 13. Preset counters 7 and 8 are connected to the proximity switch 6, and the rotation signal from the proximity switch 6 is inputted to the proximity switch 6. When the count reaches a predetermined set value, a signal is emitted. There is a difference of 2 or more between the set values of the preset counters 7 and 8. For example, if the set value of the preset counter 7 is n, the setting of the other preset counter 8 will be different. The value n+2 is selected.
9 and 10 are AND circuits, and the AND circuit 9 is connected to the preset counters 7 and 8, and upon receiving signals from these preset counters, the
The AND circuit 10 is a circuit for obtaining a logic output during a period in which the rotary support 13 rotates twice (or more), and the AND circuit 10 receives a detection signal of the rolling elements 16 in the rolling bearing 15 during a period in which the rotating support 13 rotates twice. This is a gate circuit for supplying data to the preset counter 11 described below. This preset counter 11 counts the detection signal of the rolling element 16 from the AND circuit 10, and issues an insufficiency signal when this detection signal does not reach a preset value. Reference numeral 12 is a display circuit for displaying detection results in response to a signal from the preset counter 11, and reference numeral 13 is a rotary support for rotating the rolling bearing 15, which is rotated by a drive mechanism (not shown). This rotary support 13 is provided with one slit 14 on its outer periphery. 17 is a counter reset circuit which receives a test signal from an external sequence and resets each preset counter 7,
8 and 11 to provide a reset signal.

In the above-mentioned apparatus, the reason why counting is performed during two or more revolutions of the rotary support is as follows.

Usually, a counter using an IC or the like operates by receiving either the rising edge or the falling edge of an input pulse as shown in FIG. For example, in a counter that operates based on the rising edge of a pulse, if the rising edge of the count signal of a rolling element and the falling edge of the rotational signal of a rotating support coincide with each other as shown in FIG. Counting is not performed and a counting error occurs. Therefore, when the rotary support rotates once, the count value of a good product with a counting error is the same as the count value of a defective product with one rolling element missing, making it impossible to determine whether it is good or bad. Therefore, if the rotating support is rotated twice or more, even if there is a previous counting error, there will be a difference in the count value of pass/fail. Now, the number of rolling elements is 10.
In the case of 1, if the rolling bearing is rotated twice, the rolling element count including the previous counting error is 20~
There are 19 rolling elements, and if one rolling element is missing, the counted value will be 18 to 17, making it possible to determine whether the rolling element is good or bad.

In order to detect a shortage of the rolling elements 16 arranged along the outer ring raceway surface of the rolling bearing 15 using the above device, first, the rolling bearing 15 is placed on the rotating support 13 and the rotating bearing 13 is rotated. This causes the rolling bearing 15 to rotate. Next, when the detection coil 1 is located near the rolling element 16 of the rolling bearing 15, each time the rolling element 16 passes near the detection coil 1, the inductance of the detection coil 1 changes depending on the presence or absence of the rolling element 16. A signal for detecting the rolling element 16 is obtained from the high frequency oscillation circuit 2 . This detection signal is detected by a wave detector 3, amplified by an AC amplifier 4, converted into a digital signal by a comparator 5, and input to an AND circuit 10.

On the other hand, when the slit 14 passes by the proximity switch 6 as the rotary support 13 rotates, the proximity switch 6 receives one pulse per rotation of the rotary support 13, and this pulse is sent to the preset counter. Enter 7 and 8. Here, the counter reset circuit 17 receives a test start signal from an external sequence and resets each preset counter 7, 8, 11 to a counting start state. Then, when the first pulse enters the preset counter 7, which was previously set to 1, after entering the counting start state, the rolling element counting start signal is input to the previous AND circuit 1.
0, and the preset counter 11 for counting rolling elements starts counting. Next, the rotation support 13 is
When the third pulse enters the preset counter 8 to which 3 has been previously set after the rolling element rotates and the counting starts, the rolling element counting end signal enters the AND circuit 10 and the preset counter 11 receives the third pulse. ends counting. Here, the preset counter 11 has
A value of (number of rolling elements x number of rotations of the rolling bearing) - 1 is set beforehand, and if the cumulative value of the rolling elements counted earlier reaches that set value,
The rolling bearing 15 is determined to be a good product in which the specified number of rolling elements 16 have been inserted, and if it has not reached the specified number, it is determined that the rolling bearing 15 is defective because the specified number of rolling elements 16 has not been inserted into the rolling bearing 15. Ru.

In the above-mentioned embodiment, the case where the rolling bearing rotates twice has been described, but it is also possible to judge whether the bearing is good or bad using the same concept even in the case where the rolling bearing rotates twice or more.

Since the device of the present invention is configured as described above, it is possible to accurately detect a shortage of parts in an object to be inspected without contact, and moreover, the device to be inspected can be used to count the parts of an object to be inspected. There is no need to stop accurately at the first rotation, and detection can be performed while the object to be inspected is continuously rotating, so the device itself is simple and has the advantage of being easy to incorporate into an automated line.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing a conventional detection device;
Figures 2 and 3 show the alignment of needle rollers in a needle roller bearing as an object to be inspected.
Fig. 2 is an explanatory diagram showing a state in which there are insufficient needle rollers, Fig. 3 is an explanatory diagram showing a state in which there are also insufficient needle rollers and they are lined up at an angle with respect to the outer ring flange surface, and Fig. 4 is an explanatory diagram showing a state in which there are insufficient needle rollers. Schematic explanatory diagram showing one embodiment of the present invention, No. 5
The figure is an explanatory diagram of pulses, and FIG. 6 is an explanatory diagram of a case where a detection error occurs. Explanation of symbols: 1 is a detection coil, 2 is a high frequency oscillation circuit, 3 is a detection circuit, 4 is an AC amplifier, 5 is a comparator, 6 is a proximity switch, 7 and 8 are preset counters, 9 and 10 are AND circuits, 11 is a preset counter, 13 is a rotating support, 14 is a slit, 15 is a rolling bearing, 16 is a rolling element, 17
is the counter reset circuit.

Claims (1)

[Claims] 1. A rotary support having a notch for supporting and rotating an object to be inspected, and a detection coil that uses eddy current to detect the presence or absence of a component in the object to be inspected;
a high-frequency oscillation circuit that includes the detection coil as a part of its configuration circuit; a detection circuit that detects the amplitude modulated output from the high-frequency oscillation circuit; an AC amplifier that amplifies the voltage from the detection circuit; a comparator for converting an analog signal from the rotary support into a digital signal; a proximity switch for detecting the notch of the rotary support and obtaining a signal of one pulse per rotation of the rotary support; and a proximity switch connected to the proximity switch. a second preset counter connected to the proximity switch and having a difference of 2 or more from the set value of the first preset counter; and a second preset counter connected to the first and second preset counters. an AND circuit for obtaining a logic output for a period during which the rotating support rotates at least twice;
A gate circuit is provided for transmitting detection signals of the parts of the object to be inspected during a period in which the rotary support rotates at least twice to a preset counter, and a preset counter is provided to count and preset the detection signals of the parts from the gate circuit. A component shortage detection device for an object to be inspected, which comprises a preset counter that issues a shortage signal when the preset value is not reached.