JPH0672623U - Clogging detection device - Google Patents

Abstract

(57) [Abstract] [Purpose] The Hall IC in the clogging detection device and the permanent magnet are opposed to each other, and a shield plate is erected on the operating member and positioned between them to avoid false notification of the clogging detection device. Let [Structure] An operating member 5 composed of a diaphragm 9 and a retainer 10 is arranged in the container 1, and the inside of the container 1 is divided into a negative pressure chamber 1a and a storage chamber 1b. The Hall IC 6 and the permanent magnet 7 are arranged to face each other in the storage chamber 1b. The spring 12 is contracted in the negative pressure chamber 1a. A shield plate 11 is erected on the operating member 5 and is located between the Hall IC 6 and the permanent magnet 7.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a clogging detection device used for an air cleaner of an internal combustion engine, for example, and relates to a clogging detection device that detects a negative pressure generated by intake air and notifies the filter of the clogging.

[0002]

[Prior art]

 A conventional clogging detection device is disclosed, for example, in Japanese Utility Model Publication No. 2-15533. FIG. 2 is a cross-sectional view of the clogging detection device, in which a tubular body 22 having a bottomed tubular body 21 and a partition wall 22a having an insertion hole formed in the center is horizontally fitted, is fitted into a tray. The cover 20 is attached to form the casing 20. A bellows-shaped diaphragm 24 is attached between the cylinders 21 and 22 in the casing 20 to divide it into a negative pressure chamber 20a and an atmosphere chamber 20b. The negative pressure chamber 20a communicates with the outside of the casing 20 through the port 21a. Inside the casing 20, a plate-like circuit board 25 is further provided laterally sandwiched between the upper end of the tubular body 22 and the lid 23. A control circuit is incorporated in the circuit board 25 and a hall element 26 is attached at the center. A screw member 24a is attached to the center of the diaphragm 24, and a rod-shaped body 28 having a permanent magnet 27 attached to its tip is attached to the screw member with the permanent magnet 27 facing the Hall element. The Hall element 26 has a characteristic that the output voltage of the Hall element 26 becomes OV when the permanent magnet 27 approaches, and the voltage rises when isolated. A guide cylinder 29 is mounted on the outer side of the diaphragm 24, a compression spring 30 is mounted between the guide cylinder 29 and the bottom of the cylindrical body 21, and the diaphragm 24 is biased upward.

The clogging detection device is attached to, for example, an air outlet pipe of an air cleaner, and the negative pressure chamber 20a and the negative pressure source are communicated with each other via a port 21a. When the negative pressure is transmitted to the negative pressure chamber 20a and exceeds the set pressure, the diaphragm 24 is displaced downward against the urging force of the compression spring 30, and the rod-shaped body 28 is also lowered downward so that the permanent magnet 27 at the front end is moved. Away from the element 26. If a power supply and a notification means consisting of a notification lamp are connected to the terminals connected to the circuit board 25, the output voltage of the hall element 26 will suddenly rise from OV to a large voltage, the notification lamp will light up, and the filter will be clogged. The state is notified.

[0004]

[Problems to be solved by the device]

 By the way, in this conventional clogging detection device, a rod-shaped body with a permanent magnet attached to the tip is erected at the center of the diaphragm, and is inserted into the insertion hole of the partition wall installed horizontally in the casing. The holes are sized so that a gap is formed between them so that the rod-shaped body can be lowered easily. For this reason, the rod-shaped body descends downward while inclining together with the irregular lowering of the bellows-shaped diaphragm, and the permanent magnets are displaced and face the Hall element.

Therefore, the magnetic field of the permanent magnet impinges obliquely on the Hall element, and the magnetic flux acting on the Hall element is smaller than that when vertically descending, before reaching the regular lowering position of the permanent magnet in the setting. A large voltage will be generated in the Hall element, and the notification lamp will be turned on, resulting in an erroneous clogging notification.

[0006]

[Means for Solving the Problems]

 In the clogging detection device of the present invention, the inside of the container is partitioned into a negative pressure chamber and a storage chamber by an operating member composed of a diaphragm and a retainer, and the hall IC including a Hall element and a control circuit and a permanent magnet are provided in the storage chamber. Are arranged so as to face each other, and a spring is contracted between the bottom wall of the negative pressure chamber and the operating member so that the shield plate is located between the Hall IC and the permanent magnet on the operating member. It was erected.

[0007]

[Action]

 The clogging detection device of the present invention is installed, for example, in the outlet pipe of the air cleaner of the internal combustion engine so that the inside of the pipe communicates with the negative pressure chamber, and the alarm means is connected to the Hall IC, the negative pressure inside the outlet pipe is transmitted to the negative pressure chamber. To be When the negative pressure exceeds a predetermined value, the operating member descends, and at the same time, the shield plate also descends downward and the magnetic field of the permanent magnet reaches the Hall IC. Even if the shield plate does not fall vertically, the magnetic field of the permanent magnet acts on the Hall IC with the same magnetic flux density as when vertically descending, generating a large voltage and turning on the indicator lamp, which notifies the filter clogging state. .

[0008]

【Example】

 An embodiment of the present invention will be described with reference to FIG. In the figure, reference numeral 1 denotes a container, which is formed by fitting an upper casing 2 made of synthetic resin and a lower casing 3 made of metal. The upper casing 2 has a cup-like shape, and a fitting recess 2a having a U-shaped cross section is formed around the open end of the upper casing 2. The upper wall is provided with metal-made connecting bodies 14 and 14 and is connected to the outside. A mouth 13 is provided. A U-shaped rubber tube body 15 is fitted into the atmosphere opening 13. The lower casing 3 also has a cup shape, and the periphery of the open end is bent to have a U-shaped cross section to form a fitting protrusion 3a. The bottom wall has a through hole and a part of the hole has a reduced diameter to form a restriction hole. A cylindrical metal connecting pipe 3b having a threaded portion is fixedly installed on the outer wall of the lower end.

Inside the container 1, a holding member 4 and an actuating member 5 are provided laterally with their outer peripheral edges sandwiched inside the fitting protrusion 3a of the lower casing 3, and the inside of the container 1 is accommodated with the negative pressure chamber 1a. It is divided into a chamber 1b. The holding member 4 is made of a synthetic resin and has a disk-shaped bottom wall having an opening in the center and a cylindrical side wall 3a standing on the bottom wall, and a notch 4b is formed in the side wall 4a. Inside the side wall 4a of the holding member 4, a Hall IC 6 composed of a Hall element and a control circuit which operates by the rise of a magnetic field of a single polarity is arranged by fitting one side into the notch 4b and further The magnet 7 is disposed with one pole facing the Hall IC 6 and at a position where the magnetic field rises, that is, a position where a magnetic flux density causing a sudden voltage rise acts on the Hall element. The holding member may have a pair of plate-shaped side walls standing upright with a disc-shaped bottom wall provided with an opening sandwiching the opening. One side of the Hall IC 6 is connected to a rod body 8 suspended from the upper wall of the upper casing 2. The rod body 8 has a screw portion 8a formed at the upper end for adjusting the position of the hole IC6 by moving the rod body 8 up and down. The actuating member 5 is composed of a diaphragm 9 and a retainer 10. The diaphragm 9 has a substantially thin disk shape, and is stacked on a metal-made substantially plate-shaped retainer 10 and their centers are riveted. A guide edge 10 a is provided at the open end of the retainer 10. A shielding plate 11 integrated with the rivet is erected on the diaphragm 9. The shield plate 11 is made of metal such as iron, nickel and cobalt, or a magnetic shield material such as synthetic resin in which powder of these metals is kneaded. The lower part is formed in a substantially cylindrical shape and the upper part is formed in a flat plate shape.

In the negative pressure chamber 1 a of the container 1, the retainer 10 guide edge 10 a of the operating member 5 is inserted into the lower casing 3, and the coiled spring 12 is contracted between the bottom wall of the lower casing 3 and the retainer 10. To be done. As a result, the actuating member 5 is urged by the holding member 4, and in the storage chamber 1b, the shield plate 11 is inserted from the opening of the holding member 4 into the side wall 4a and the upper portion is cut between the Hall IC 6 and the permanent magnet 7. Located in the state.

The Hall IC 6 has a power supply terminal, an output terminal and a contact terminal. The power supply terminal and the output terminal are connected to the connecting bodies 14 and 14 of the upper casing 2, respectively, and the ground terminal is connected to the lower casing 3. It

The Hall IC and the permanent magnet are formed by forming plate-like holding walls projecting inwardly on the inner wall of the upper casing so as to face each other, and disposing them on the wall surfaces facing each other, or the upper casing upper wall. It is also possible to arrange two rods so that they face each other and hang down so as to be connected to their lower ends. In this case, the holding member is a disc-shaped member having an opening at the center.

In these clogging detection devices, a communication pipe 3b is connected to an outlet pipe of an air cleaner of an internal combustion engine (not shown), and further, a connection means (not shown) including a power source and a notification lamp is connected to the connection bodies 14, 14. Are connected. The negative pressure generated by the air sucked into the internal combustion engine is transmitted to the negative pressure chamber 1a of the clogging detection device, and the filter in the air cleaner traps the dust in the intake air, increasing the negative pressure on the outlet pipe side and increasing the negative pressure. When the negative pressure in the pressure chamber 1a becomes equal to or higher than a predetermined value, a negative pressure larger than the urging force of the spring 12 acts on the operating member 5 and the operating member 5 descends. At the same time, the shield plate 11 provided upright on the actuating member 5 also descends downward so that there is no obstruction of the magnetic field between the Hall IC 6 and the permanent magnet 7, and the magnetic field of the permanent magnet 7 reaches the operating magnetic flux density of the Hall element as it is. . At this time, even if the upper end of the shield plate 11 crosses the magnetic flux diagonally to shield, the right half magnetic flux corresponding to the left half shielded magnetic flux reaches the Hall IC 6 as shown in the schematic diagram of FIG. However, when the shield plate 11 descends vertically (two points and a chain line), the same magnetic flux density is obtained. Therefore, when the negative pressure in the negative pressure chamber 1a reaches a predetermined value, a large voltage is inevitably generated in the Hall IC 6 and the notification lamp is turned on.

The clogging detection device of the present invention is mounted on the outlet pipe of the air cleaner, and is installed in a place where the pressure in the negative pressure chamber falls below atmospheric pressure, such as an air filter of an air conditioner or an air purifier for a vehicle. The clogging of the filter can also be detected by mounting.

[0015]

[Effect of device]

 As described above, in the clogging detection device of the present invention, the inside of the container is divided into the negative pressure chamber and the storage chamber by the operating member, and the holding member is provided horizontally in the storage chamber so that the side wall hole IC and the permanent magnet face each other. Since the operating member is provided with a shield plate standing upright and positioned between the Hall IC and the permanent magnet, a negative pressure corresponding to a predetermined value is applied to the negative pressure chamber and the operating member descends at the same time. The shield plate that has blocked the magnetic field of the magnet vertically or obliquely also reaches the hall I C by the magnetic field of the permanent magnet. At this time, the magnetic flux density that uniformly causes a rapid voltage rise is applied to the Hall IC regardless of any descending state including the vertical descending of the shield plate. Therefore, if a predetermined negative pressure is transmitted to the negative pressure chamber, a large voltage is inevitably generated between the output terminal and the ground terminal of the Hall IC. For example, if the clogging detection device is installed in the air cleaner, the clogging of the regular filter will occur. It detects the condition and notifies it to avoid false notification.

[Brief description of drawings]

FIG. 1 is a diagram of a clogging detection device according to an embodiment of the present invention.

FIG. 2 is a diagram of a conventional clogging detection device.

FIG. 3 is a schematic diagram showing a shielding state of magnetic flux.

[Explanation of symbols]

 1 Container 1a Negative Pressure Chamber 1b Storage Chamber 5 Operating Member 6 Hall IC 7 Permanent Magnet 11 Shield Plate 12 Spring

Claims (1)

[Scope of utility model registration request] 1. An inside of the container is partitioned into a negative pressure chamber and a storage chamber by an operating member composed of a diaphragm and a retainer, and a Hall IC including a Hall element and a control circuit and a permanent magnet face each other in the storage chamber. Clogs that are respectively arranged, a spring is contracted between the bottom wall of the negative pressure chamber and the operating member, and a shielding plate is erected on the operating member so as to be located between the Hall IC and the permanent magnet. Detection device.