JPS6324732B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present application relates to a clogging detection device for an air cleaner for an internal combustion engine.

The clogging sensing device detects the clogging state of the filter element in the air cleaner, and when the clogging state exceeds a predetermined level, it issues an alarm that it is time to replace the filter element. This type of device associates the clogging state with a negative pressure value on the clean side of the filter element, and uses the negative pressure to activate a clogging sensing mechanism, such as a diaphragm equipped with an indicator. However, the following problems occur in devices operated by negative pressure as described above. First, it is necessary to fine-tune the spring etc. in advance so that it operates accurately at a predetermined negative pressure value, and it takes a great deal of effort to do this during assembly. Second, vibrations occurring in the internal combustion engine or sudden changes in negative pressure may cause the sensing mechanism to malfunction, resulting in inaccurate alarms.

Accordingly, the present application provides a clogging sensing device that is operated by a negative pressure source and has a structure that allows for easy adjustment and more accurate operation.

FIG. 1 shows a clogging detection device 10, which consists of upper and lower casings 1 and 2, an operating body 3, and a microswitch 4. The upper casing 1 has an annular flange portion 5, and a micro switch 4 is held therein. The lower casing 2 has an inlet portion 7 containing a filter 6 on one side, and the periphery of the other open end is crimped 8 to the annular flange portion 5 of the upper casing 1, thereby fixing the upper and lower casings. An actuating body 3 is disposed between the upper and lower casings 1 and 2, and a chamber formed inside the casing is divided into a negative pressure chamber 9 and a storage chamber 11. 12 is an opening communicating with the atmosphere. The actuating body 3 is made up of a diaphragm 13 and a retainer 14 stacked one on top of the other and a press pin 15 provided in the center thereof, and a spring 16 is compressed between the retainer 14 and the inner wall of the lower casing 2. .

The microswitch 4 in the storage chamber 11 is a conventionally well-known type that conducts or interrupts an electric circuit, which will be described later, and is a rectangular type equipped with connection terminals 17, 18 and a switching terminal 19. Also,
The microswitch 4 has hysteresis characteristics.

The pressing pin 15 of the actuating body 3 is normally in contact with the switching terminal 19 of the micro switch 4 and is in a state of pressing the terminal. Further, the microswitch 4 in the storage chamber 11 is adjusted and positioned to be activated, that is, turned on and off (ON-OFF) under predetermined conditions, and is fixed there.

FIG. 2 shows an embodiment of the clogging detection device of the present invention, in which a holding case 20 for storing and holding the microswitch 4 is arranged in the storage chamber 11 in FIG. Here, the holding case 20 is
As shown in FIG. 3, it is a rectangular box without a bottom plate, with a pressing wall 21 made of, for example, a thin plate spring material on one side, and the opposite side forming a side wall perpendicular to the bottom.

In the above clogging detection device, a warning lamp 22 or a buzzer (not shown) and a circuit 24 connected to a power source 23 are connected to the connection terminals 17 and 18 of the microswitch 4. Further, the inlet portion 7 of the lower casing 2 is connected to the clean side (not shown) of the filter element.

In the device shown in FIG. 1, when the engine is stopped, that is, when no negative pressure is generated on the clean side of the filter element and the inside of the negative pressure chamber 9 is at atmospheric pressure, the pressing pin 15 of the actuating body 3 is moved by the spring force of the spring 16. Therefore, the switching terminal 19 of the micro switch 4 is pressed to turn it off (OFF) and cut off the circuit. When the engine starts and the intake air flows through the filter element, a negative pressure (pressure below atmospheric pressure) is generated on the clean side, which causes the air in the negative pressure chamber 9 of the device communicating with the clean side to The air is exhausted and the pressure in the room becomes negative as well. Due to this negative pressure, the actuating body 3 moves against the spring force of the spring 16. When the filter element reaches a predetermined clogging state, that is, the set negative pressure value, the pressing pin 15 of the actuating body 3 separates from the switching terminal 19 of the micro switch 4, and the switching terminal 1
9 to the switch-on (ON) state.
Accordingly, the circuit 24 becomes conductive, emitting light from a warning lamp 22 disposed in the driver's cab to warn of the clogging condition. Due to the hysteresis characteristic of the micro switch 4, the switching of the circuit 24 turns on the negative pressure in the negative pressure chamber 9 exactly at the set value, but in the case of switching off, the negative pressure in the negative pressure chamber 9 turns on at the set value (a pressure close to atmospheric pressure). ) will operate. In other words, even if the negative pressure in the negative pressure chamber 9 becomes lower than the set value in a clogged state, the warning lamp 22 continues to emit light within a predetermined range.

Next, a method for holding and adjusting the micro switch 4 will be explained. In the apparatus shown in FIG. 2, a holding case 20 is fixed within the storage chamber 25 of the upper casing 1, and the micro switch 4 is disposed within the case. The microswitch 4 held within the case 20 is slidable due to the presence of the pressing wall 21. The negative pressure in the negative pressure chamber 9 is set to a set value, and the microswitch 4 is slid to a point where the switching terminal 19 is turned on by this negative pressure, and is fixed, for example, with an adhesive.

As described above, the clogging detection device of the present invention uses a micro switch with hysteresis characteristics, and when the filter element is clogged, the negative pressure in the negative pressure chamber decreases depending on the engine operating condition. Since the warning lamp is emitted even in the event of a malfunction, accurate operation without malfunction can be achieved. Further, since this device has a structure in which the microswitch is slidably held in a holding case having a pressing wall, even when the set pressure is a minute value, it can be easily adjusted.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a clogging sensing device, FIG. 2 is a sectional view showing an embodiment of the clogging sensing device of the present invention, and FIG. 3 is a perspective view of the holding case in FIG. 2. 1... Upper casing, 2... Lower casing, 3
...Operating body, 4...Micro switch, 21,3
3,43...pressing wall.

Claims (1)

[Claims] 1 A chamber formed by an upper casing and a lower casing having an inlet part is divided into a negative pressure chamber and a storage chamber by an actuating body consisting of a diaphragm, a retainer, and a pressing pin, and the storage chamber has a pressing wall on one side. A holding case made of a box having side walls perpendicular to the bottom surface is installed on the other side facing the case, and a rectangular micro switch with hysteresis characteristics is held and fixed in pressure contact with the pressing wall, and a negative pressure is applied. A clogging detection device for an air cleaner in which a spring is contracted in a chamber to press a pressing pin of an operating body against a micro switch, and the micro switch is turned on and off by negative pressure fluctuations in the negative pressure chamber.