JPH059798Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The invention detects when the oil level of an internal combustion engine falls below a predetermined level and controls the ignition system for the internal combustion engine to stop its operation. This invention relates to an oil level detection control unit for an internal combustion engine.

[Prior Art] When the level of lubricating oil in an internal combustion engine falls below a permissible lower limit level, if the engine continues to be operated, the engine may be damaged. Therefore,
An oil level detection system that is equipped with a detection device that detects the oil level of an internal combustion engine, and when it is detected that the oil level has fallen below the allowable lower limit level, the operation of the ignition device for the internal combustion engine is stopped and the engine misfires. Control units are provided to protect the internal combustion engine by shutting it down when the oil level falls below a lower permissible level.

A conventional oil level detection control unit for an internal combustion engine includes an oil level detection device inserted into the oil pan through a screw hole provided in the oil pan of the internal combustion engine, and an ignition device control device connected to the oil level detection device. When the oil level falls below the allowable lower limit level and the oil level detection device performs a detection operation, the ignition device control switch circuit is closed and the ignition device control switch circuit starts the ignition for the internal combustion engine. The ignition operation is stopped by short-circuiting a part of the device.

[Problems to be solved by the invention] In the conventional oil level detection control unit, the circuit board constituting the ignition device control switch circuit is provided separately from the oil level detection device.
Since it was fixed in place with a single bolt, there was a risk of the circuit board coming off due to vibration, etc.

In addition, in the conventional oil level detection control unit, the ignition phase value control switch circuit was connected to the ignition device via a lead wire, so there was a problem that the lead wire got in the way when the unit was being installed and removed.

[Means for Solving the Problems] The present invention includes a case 1 that is inserted into an oil pan of an internal combustion engine through a screw hole provided in the oil pan, and a case 1 that is housed in the case 1 and that is inserted into the oil pan. a float 2 that moves up and down following the oil level; a proximity switch 5 that operates by detecting the position of the float when the oil level falls below the allowable lower limit level; An engine stop control switch that short-circuits a part of the ignition device to stop the operation of the ignition device, and parts that constitute a trigger circuit that conducts the engine stop control switch when the proximity switch is activated are mounted on a circuit board. The subject matter is an oil level detection control unit for an internal combustion engine, which is equipped with a device control switch circuit.

In the present invention, the case 1 includes a board storage chamber 1 surrounded by a wall 108 having a board contacting surface 110 on which the circuit board 3 comes into contact and having a hexagonal cross section.
09, and a proximity switch storage chamber 10 with one end open to the board contacting surface of the board storage chamber 109 and the other end closed.
5, and a float storage chamber 1 that is provided to surround the proximity switch storage chamber 105 and stores the float 2.
04, and a board locking means 111 that is provided to protrude from the board contact surface 110 and elastically engages with the circuit board 3 to lock the circuit board. A screw 11 is screwed into the screw hole of the oil pan on the outer surface of the peripheral wall surrounding the float storage chamber of the case.
6 is formed.

The circuit board 3 is placed in the board storage chamber 109 and is locked by a board locking means 111 while in contact with a board contacting surface 110 . The proximity switch 5 is inserted into the proximity switch storage chamber 109 with its terminal conductors 5a and 5b soldered to the circuit board 3, and the circuit board 3 is provided with a switch circuit for connecting an ignition device control to an ignition device for an internal combustion engine. Plug terminals 7A and 7B are fixed. The board storage chamber is filled with an insulating resin 10, which fixes the circuit board and protects the components mounted on the board.

[Operation of the device] By using a case having an integrated board housing chamber, a proximity switch housing chamber, and a float housing chamber as described above, the circuit board constituting the ignition device control switch circuit and the oil level detection device are integrated together,
This eliminates the risk of the circuit board coming off due to vibration or the like, thereby improving reliability.

In addition, when the plug terminal is fixed to the circuit board as described above, the ignition control switch circuit can be connected to the ignition device using this plug terminal, so when installing or removing the unit, the ignition control switch circuit and ignition The lead wire connecting to the device can be removed, and the lead wire can be prevented from interfering with the attachment and detachment of the unit.

Furthermore, by attaching the proximity switch to the circuit board as described above and inserting the proximity switch into the proximity switch storage chamber of the case, the proximity switch can be attached at the same time as the circuit board is attached.
The unit can be easily assembled. In this case, the circuit board is always mounted in contact with the board contacting surface of the case, so the proximity switch can always be positioned in a fixed positional relationship.
Variations in detection accuracy of the oil level detection device can be prevented.

Furthermore, if the case is provided with a board fixing means that resiliently engages with and locks the circuit board, the circuit board can be easily fixed.

Further, as described above, if the wall surrounding the substrate storage chamber has a hexagonal cross-sectional shape, a wrench can be engaged with this wall, so that the unit can be easily attached.

[Embodiments] Examples of the present invention will be described below with reference to the accompanying drawings.

1 and 2 show an embodiment of the present invention, with FIG. 1 being a longitudinal sectional view and FIG. 2 being a bottom view of the unit. In these figures, 1 is a unit case integrally molded from resin or the like, and this case 1 is equipped with a cylindrical float storage tube section 100, one end of which is closed by a bottom wall section 101. . An opening 102 is provided in the center of the bottom wall 101, and one end of a cylindrical proximity switch housing cylindrical portion 103 extending concentrically within the cylindrical portion 100 is continuous to the periphery of the opening 102. are doing. The other end of the proximity switch storage cylindrical portion 103 reaches outward from the other end of the float storage cylindrical portion 100, and the other end of the proximity switch storage cylindrical portion 103 is closed by an end wall. Float storage cylinder part 100 peripheral wall part and proximity switch storage cylinder part 10
The annular space between the peripheral wall of No. 3 and the surrounding wall portion is a float storage chamber 104, and this float storage chamber 104
An annular float 2 is housed inside. Further, a proximity switch storage chamber 105 is formed inside the proximity switch storage cylindrical portion 103, and a lid plate 106 welded to the outer periphery of the other end of the float storage cylindrical portion 100 and the proximity switch storage cylindrical portion 103 provides space for float storage. The opening at the other end of the cylindrical portion 100 is closed. Further, a flange portion 107 is formed at one end of the float storage cylinder portion 100, and this flange portion 107
The lower surface of is flush with the lower surface of the bottom wall portion 101 (the surface opposite to the cylindrical portion 100). Flange part 107
A wall portion 108 having a regular hexagonal cross section is integrally provided on the lower surface of the board, and a circuit board storage chamber 109 is formed inside this wall portion 108 . The dimensions of the wall portion 108, which has a hexagonal cross-sectional shape, are set to a size that conforms to the JIS standard for nuts so that a spanner can be fitted into this wall portion.

Of the plane formed by the lower surface of the bottom wall portion 101 and the lower surface of the flange portion 107, the circuit board storage chamber 1
09 is a substrate abutting surface 110, and a plurality of snap pins 111 constituting a substrate locking means are integrally provided on this substrate abutting surface 110. The snap pin 111 has a tapered head 112 at its tip, and a groove 113 is formed in the head 112. This split groove gives elasticity to the head 112, and when the head is inserted into a hole in a substrate to be described later, the diameter of the head contracts and the head can elastically fit into the hole in the substrate. It's becoming like that.

A circuit board 3 equipped with parts constituting an ignition control switch circuit to be described later is stored in the board storage chamber 109, and a snap pin 111 is elastically engaged in a hole provided in the circuit board. .
The length of the lower part of the neck of the snap pin is set to be equal to or slightly smaller than the thickness of the circuit board 3, so that the head 112 of the snap pin 111 that has passed through the hole in the circuit board comes into contact with the circuit board 3. The circuit board 3 is in contact with the surface opposite to the contact surface 110.
is adapted to be locked in a state in which it is brought into contact with the substrate contacting surface 110.

Proximity switch storage chamber 10 in the center of the circuit board 3
One end of a reed switch 5 constituting a proximity switch is brought into contact with the portion facing the reed switch 5 via an insulating collar 4 having a predetermined length in the axial direction. The reed switch 5 is arranged to extend in the axial direction within the proximity switch storage chamber 105, and the terminal conductor (lead wire) 5a led out from one end of the reed switch 5 is connected to the inside of the collar 4 and the through hole of the circuit board 3. through which it is led out to the side opposite to the substrate contact surface 110. Further, the terminal conductor 5b led out from the other end side of the reed switch 5 is folded back to the circuit board 3 side,
It is inserted into the through hole of the substrate 3 through the outer side of the collar 4. The surface 3a of the circuit board 3 opposite to the board contact surface 110 is a soldering surface, and the terminal conductors 5a and 5b of the reed switch 5 led out to this soldering surface are provided on the soldering surface 3a. It is soldered to a predetermined conductive part.

An integrated circuit electronic component 6 is arranged on the soldering surface of the circuit board 3, and the electronic component 6 is soldered to a predetermined conductive portion, and the electronic component 6 constitutes a switch circuit for controlling the ignition device. There is.

The soldering surface of the circuit board 3 is also provided with a pair of conductive parts constituting the output terminals of the ignition control circuit, and each of the pair of conductive parts is provided with one end of a pair of plug terminal fittings 7A and 7B. is soldered. The plug terminal fittings 7A and 7B extend perpendicularly to the board surface of the circuit board 3, protrude outward from the board storage chamber 109, and are connected to terminal conductors 8A and 7B connected to an ignition device to be described later. A receptacle 9 connected to 8B is connected to the receptacle 9 in a detachable manner. The inside of the board storage chamber 109 is filled with an insulating resin 10, and the circuit board 3 is fixed and protected by this resin.

A permanent magnet 11 is attached to the inner periphery of the float 2, and the permanent magnet 11 operates the reed switch 5 when the position of the float 2 falls below a predetermined allowable lower limit level. In this example, a normally open type reed switch 5 is used, and the reed switch 5 closes when the float 2 descends to a position below a predetermined allowable lower limit level.

A hole 115 for letting oil in and out is provided in the peripheral wall of the float housing cylinder 100, and a hole 115 for letting oil in and out is provided at the end of the peripheral wall on the flange 107 side. A mating screw 116 is provided.

In addition, the bottom surface of the float storage chamber 104 and the lid plate 10
6 has a convex strip 11 extending in the circumferential direction on the inner surface of each
7 and 118 are provided, and these protruding stripes prevent the float 2 from coming into close contact with the bottom surface of the float storage chamber or the inner surface of the lid plate 106, respectively.

The above-mentioned parts constitute an oil level detection control unit U for an internal combustion engine.

The above-mentioned detection control unit U inserts the float storage cylindrical portion 100 into the oil pan through a screw hole provided in the oil pan of an engine (not shown), and screws the screw portion 116 into the screw hole of the oil pan. It can be attached to the engine by fitting it together. In the present invention, since the wall portion 108 surrounding the substrate storage chamber 109 is formed to have a hexagonal cross section, a spanner is directly engaged with this wall portion 108.
The screws 116 can be tightened. Also, when installing unit U on the engine, plug terminal 7
Since it is sufficient to remove the receptacle 9 from A and 7B, the lead wires 8A and 8B do not get in the way, and the unit can be easily installed.

The ignition device control switch circuit configured on the circuit board 3 includes an engine stop control switch that short-circuits a part of the ignition device for an internal combustion engine to stop the operation of the ignition device when conductive, and a reed switch 5 (nearby). When the reed switch 5 is activated when the oil level falls below the allowable lower limit level, the engine stop control switch is activated. As a result, a part of the ignition device for the internal combustion engine is short-circuited and the ignition operation is stopped, so that the engine misfires and eventually stops, thereby preventing damage to the engine.

As in the above embodiment, the proximity switch (reed switch 5 in the above example) is mounted in contact with the board 3 via the collar 4, and
If the reed switch 5 is attached to the case in contact with the board contact surface 110, the reed switch 5 can be positioned accurately by setting the dimensions of the collar 4 to a predetermined value. Therefore, the allowable lower limit level of the oil level can always be set accurately, and variations in detection accuracy can be reduced. Furthermore, by changing the length of the collar 4, the lower limit level can be changed.

Further, as described above, when the two terminal conductors 5a and 5b led out from the reed switch are arranged through the inside and outside of the collar 4, the terminal conductors 5a and 5
b. contact can be prevented.

As in the above embodiment, if the soldering surface of the circuit board 3 is set opposite to the board contact surface 110 and all components are soldered on this soldering surface, the circuit board 3 Since it can be brought into close contact with the board contact surface, it is possible to prevent unnecessary space from being formed between the board 3 and the board contact surface.
The unit can be made smaller. Furthermore, since the circuit board 3 can be brought into close contact with the board contact surface, not only can the reed switch be positioned accurately, but also the resin 10 can be prevented from flowing into the reed switch 5 side.

As in the above embodiment, a board locking means that resiliently engages with the circuit board to lock the board is provided, and the circuit board is brought into contact with the board contacting surface by this locking means. By locking, the circuit board can be attached to the case 1 with a single touch, and the unit can be easily assembled.

In the above embodiment, the snap pin 111 is used as the board locking means, but this board locking means elastically engages the circuit board 3 to bring the circuit board into contact with the board contact surface. It is not limited to a snap pin, as long as it can be locked to the pin. For example, as shown in FIG.
The claws 120, 120, . . . having a
10, and the circuit board 3 may be locked by elastically engaging the hook-shaped portions 120a of these claws with both ends of the circuit board 3.

Next, the configuration of the ignition device control switch circuit 20 will be explained with reference to FIG. 21 in Figure 4
is an ignition coil, and at least one of the ignition coils
The secondary coil 21a is placed in a magnet generator driven by an engine (not shown), and an alternating current voltage is induced in the primary coil 21a in synchronization with the rotation of the engine. That is, in this example, the primary coil 21a also serves as a power source for the ignition device. One ends of the primary coil 21a and secondary coil 21b of the ignition coil 21 are grounded,
A spark plug 22 attached to a cylinder of an engine (not shown) is connected to both ends of the secondary coil 21b. The emitter of a transistor 23 whose collector is grounded is connected to the non-grounded terminal of the primary coil 21a, and the ignition coil 21, the spark plug 22, the transistor 23, and the trigger circuit (not shown) of this transistor operate the internal combustion engine. An ignition system is configured. This ignition device is a current interrupt type device, and when a voltage V1 in the direction of the arrow shown in the figure is induced in the primary coil 21a, a base current is applied to the transistor 23 and the transistor 23 becomes conductive. When the transistor 23 becomes conductive, a short-circuit current flows from the primary coil 21a through the collector and emitter of the transistor 23.
Next, when the engine ignition timing comes, the transistor 23
is cut off, and as a result, the primary coil 21a
The current flowing through is cut off. By interrupting this current, a high voltage is induced in the primary coil 21a, and this voltage is further increased to induce a high voltage for ignition in the secondary coil 21b. Since this high voltage is applied to the ignition plug 22, a spark is generated at the ignition plug and the engine is ignited.

The ignition device control switch circuit 20 includes a thyristor 25 as an engine stop control switch and a trigger circuit 26 for the engine stop control switch. The trigger circuit 26 is connected to one of the ignition coils.
A diode 27 whose anode is connected to the non-grounded terminal of the next coil 21a via a lead wire 8B and a plug terminal 7B, and a capacitor 2 whose one end is connected to the cathode of the diode 27 via a resistor 28.
9, a diode 30 whose anode is connected to the other end of the capacitor 29 and whose cathode is connected to the terminal conductor 5a of the reed switch 5, and a Zener diode 31 connected in parallel to both ends of the capacitor 29.
, a resistor 32 connected between the anode of the diode 30 and the terminal 7B, a capacitor 29 and a resistor 28
a diode 34 whose anode is connected to the connection point via a resistor 33; a capacitor 35 connected between the cathode of the diode 34 and the terminal 7B;
A resistor 36 connected between the diode 34 side terminal of the capacitor 35 and the gate of the thyristor 25
It is made up of. Further, the anode of the thyristor 25 is connected to the terminal conductor 5b of the reed switch 5.

A diode 37 for preventing reverse voltage to the gate is connected between the gate and cathode of the thyristor 25, with its anode facing the cathode side of the thyristor 25, and a capacitor for preventing erroneous firing is connected between the gate and cathode of the thyristor 25. 38 are connected.

Also, the rate of change dV/dt of the voltage between the anode and cathode of the thyristor 25 becomes excessive, causing the thyristor 25 to
A series circuit of a capacitor 39 and a resistor 40 is connected between the anode and cathode of the thyristor 25 in order to prevent the thyristor 25 from becoming conductive.

In the circuit of FIG. 4, when the oil level falls below the allowable lower limit level and the reed switch 5 is closed, a voltage V1 in the direction opposite to the arrow shown in the figure is induced in the primary coil 21a, and the diode 27, Current flows through the resistor 28, capacitor 29 and diode 30, and the capacitor 2
9 is charged to the Zener voltage of the Zener diode 31. The charge on this capacitor 29 is the resistance 3
3, diode 34, and capacitor 35, thereby charging capacitor 35 to the polarity shown. The charge on the capacitor 35 is the resistor 3
6 and the gate cathode of the thyristor 25, and an ignition signal is given to the thyristor 25. As a result, the thyristor 25 becomes conductive during a half cycle in which a voltage in the direction of the arrow shown in the figure is induced in the primary coil 21a (a half cycle in which ignition operation is performed), and both ends of the primary coil 21a (ignition power source) are substantially short-circuited. to prevent ignition operation. Thyristor 2
5 becomes conductive once, the voltage drop between its gate and cathode is applied to the capacitor 35 through the resistor 36, so that the capacitor 35 is charged. Since the charge in the capacitor 35 is discharged through the resistor 36 and the gate cathode of the thyristor 25, when a voltage in the direction of the arrow shown in the figure is induced in the primary coil 21a, the thyristor 25 becomes conductive again. By repeating these operations, the thyristor 25 becomes conductive repeatedly as long as the engine is rotating and a voltage is induced in the primary coil 21a, and the engine continues to misfire. This stops the engine and prevents damage to the engine due to low oil levels.

FIG. 5 shows the main part of another configuration example of the ignition device control switch circuit used in the present invention. In this example, a resistor 41 is connected in series with the thyristor 25.
is connected, and the anode of the diode 42 is connected to the cathode of the thyristor 25. A capacitor 43 is connected between the cathode of the diode 42 and the terminal 7B.
A light emitting diode 45 is connected to both ends of the capacitor 43 via a resistor 44.

In the circuit shown in FIG. 5, when the oil level falls below the allowable lower limit level and the thyristor 25 becomes conductive, the voltage across the resistor 41 is applied to the capacitor 43.
is charged, and the voltage across the capacitor 43 is applied to the light emitting diode 45. This causes the light emitting diode 45 to emit light, indicating that the oil level has fallen below the allowable lower limit level.

In the above embodiment, a current interrupt type ignition device is used as the ignition device for the internal combustion engine, but the unit of the present invention can be used when other types of ignition devices are used, such as capacitor discharge type ignition devices. can also be applied.

Furthermore, in the above example, the thyristor 25 as a switch for stopping the ignition operation is connected to both ends of the ignition power supply, but this switch
It may be connected to both ends of the part that stops the ignition operation when short-circuited. For example, if a signal coil is provided to determine the ignition timing, it may be connected to both ends of the signal coil.

[Effects of the invention] As described above, according to the invention, the circuit board constituting the ignition device control switch circuit and Since it is integrated with the oil level detection device, it is possible to eliminate the risk of the circuit board coming off due to vibration etc., and reliability can be improved. In addition, the plug terminal is fixed to the circuit board so that the ignition device control switch circuit can be connected to the ignition device using the plug terminal, so when installing or removing the unit, the ignition device control switch circuit and the ignition device can be connected. The lead wire connecting between the two can be removed, and the lead wire can be prevented from interfering with the installation and removal of the unit. Furthermore, by attaching the proximity switch to the circuit board as described above and inserting the proximity switch into the proximity switch storage chamber of the case, the proximity switch can be attached at the same time as the circuit board is attached, making assembly of the unit easier. It can be done. In this case, since the circuit board is always mounted in contact with the board contacting surface of the case, the proximity switch can always be positioned in a constant positional relationship, which prevents variations in the detection accuracy of the oil level detection device. I can do it. Furthermore, since the case is provided with a board fixing means that elastically engages with and locks the circuit board, the circuit board can be easily fixed. Further, since the wall surrounding the substrate storage chamber has a hexagonal cross-sectional shape, a spanner can be engaged with this wall, and the unit can be easily attached.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, FIG. 2 is a bottom view of the detection control unit portion of FIG. 1,
FIG. 3 is a vertical sectional view showing the main parts of another embodiment of the present invention, FIG. 4 is a circuit diagram showing an example of the configuration of a switch circuit for controlling the ignition device used in the present invention, and FIG. FIG. 3 is a circuit diagram showing a main part of another example of the configuration of the switch circuit. 1... Case, 104... Float storage chamber, 1
05... Proximity switch storage chamber, 109... Board storage chamber, 110... Board contact surface, 2... Float,
3...Circuit board, 4...Color, 5...Reed switch, 7A, 7B...Plug terminal, 10...Resin, 11...Magnet.

Claims (1)

[Scope of Claim for Utility Model Registration] A case that is inserted into an oil pan of an internal combustion engine through a screw hole provided in the oil pan, and a case that is housed in the case and moves up and down in accordance with the oil level in the oil pan. a proximity switch that operates by detecting the position of the float when the oil level falls below a permissible lower limit level; An ignition device control switch circuit comprising an engine stop control switch for stopping the operation of the device and a component constituting a trigger circuit for conducting the engine stop control switch when the proximity switch is activated, mounted on a circuit board. In the oil level detection control unit for an internal combustion engine, the case includes a board storage chamber surrounded by a wall having a hexagonal cross section and having a board contacting surface for contacting the circuit board; a proximity switch storage chamber that is open to the board contact surface of the board storage chamber and whose other end is closed; a float storage chamber that is provided to surround the proximity switch storage chamber and stores the float; The outer surface of the peripheral wall surrounding the float storage chamber includes a board locking means that is provided to protrude from the surface and elastically engages with and locks the circuit board, and A screw is formed to be engaged with a screw hole of the oil pan, and the circuit board is placed in the board storage chamber and is locked by the board locking means while in contact with the board contacting surface. The proximity switch is inserted into the proximity switch storage chamber with its terminal conductor soldered to the circuit board, and the circuit board has a plug terminal for connecting the ignition device control switch circuit to the internal combustion engine ignition device. An oil level detection control device for an internal combustion engine, characterized in that: is fixed, and the board storage chamber is filled with an insulating resin.