JP2008196411A - Oil sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oil sensor improved to provide stable detection value without dropping detection accuracy. <P>SOLUTION: The oil sensor 7 is provided with a ventilation hole 18 at a position projecting above an oil level surface, with an oil flow-in hole 17 at a position sinking under the oil level surface, and with a sensing part 11 touching engine oil stored in an oil pan 2 and outputting signal according to parameters of the engine oil. The oil sensor 7 is provided with a cover member 21 covering the whole circumference of a part projecting above the oil level surface including a part at which the ventilation hole is provided in the sensing part and sunk under the oil level surface at a lower end part thereof. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an oil sensor provided in an oil pan for storing engine oil and detecting a parameter of engine oil.

  There is known an oil remaining amount sensor including a detection body capable of taking out an output value corresponding to an area ratio with respect to the entire portion immersed in engine oil (see Patent Document 1).

This oil remaining amount sensor is configured by housing a detection body that contacts the engine oil stored in the oil pan and outputs a signal corresponding to the parameter of the engine oil in the cover. A cover containing the detection body is inserted upward into the oil pan through the formed opening, and then fixed to the bottom wall of the oil pan. In the cover, an oil inflow hole for allowing engine oil to enter and exit from the cover is formed in a portion of the oil pan that is recessed below the oil level, and a vent hole for introducing the oil pan internal pressure into the cover is formed. It is formed in the part which protruded in the oil surface space in an oil pan.
JP 2003-83935 A

  However, the oil level in the oil pan may oscillate due to vibrations during traveling, etc., which may cause oil droplets to scatter and enter the cover through the vent hole. If the engine oil that has entered through the vent hole in this way adheres to the detection body, it may adversely affect the detection accuracy of the remaining amount of oil. Further, the fluctuation of the oil level directly leads to fluctuations in the output of the detection body, which makes the detected value of the remaining oil level unstable.

  The present invention has been devised to eliminate such inconveniences, and a main object of the present invention is to provide an oil sensor improved so that a stable detection value can be obtained without degrading detection accuracy. There is.

In order to solve such a problem, claim 1 of the present invention is a sensing in which a vent hole 18 is provided at a position protruding above the oil level OL and an oil inflow hole 17 is provided at a position where the oil hole is immersed below the oil level. In the oil sensor 7 in which a detecting body that contacts the engine oil stored in the oil pan 2 and outputs a signal corresponding to the parameter of the engine oil is housed in the portion 11, a vent hole in the sensing portion is provided. And a shielding member 21 that covers the entire circumference of the portion that protrudes above the oil level including the portion that has been immersed in the lower end of the oil surface.
According to a second aspect of the present invention, the shielding member covers the periphery from the entire portion of the sensing portion that protrudes above the oil surface to at least a portion of the portion that is submerged below the oil surface, and protrudes above the oil surface. The second ventilation hole 23 is provided at a position that does not overlap with the ventilation hole of the sensing unit when viewed from the outer surface of the part.
Further, in claim 3, a flange 22 parallel to the oil surface is provided at the lower end portion of the shielding member that is immersed below the oil surface, and the shielding member is fixed to the oil pan with the flange.
In claim 4, the oil sensor is attached to the oil pan together with the shielding member. In particular, in claim 5, a female screw hole for screwing the bolt B1 for fastening the oil sensor from the outside of the oil pan is provided. The boss 16 is projected from the inner surface of the bottom wall of the oil pan, and a female screw hole is provided in the boss 16 for screwing a bolt B3 for fastening the flange of the shielding member from the inside of the oil pan.

According to such a configuration of claim 1 of the present invention, by providing the lower end portion of the shielding member at a position lower than the oil surface, oil level fluctuation around the oil sensor can be prevented at the lower end portion of the shielding member, and It is possible to effectively prevent the splash of engine oil from entering from the lower end opening of the shielding member.
In particular, according to the configuration of claim 2, since all of the upper part of the oil surface of the oil sensor is covered with the shielding member, the positions of the ventilation hole of the sensing unit and the second ventilation hole of the shielding member are shifted, It is possible to more reliably prevent oil droplets from entering the sensing unit.
Further, according to the configuration of the third aspect, the engine oil can be prevented from moving in the vertical direction by the flange, so that the action of suppressing the oscillation of the oil surface around the oil sensor can be further enhanced, and the engine oil can be contained in the engine oil. Since the generated air bubble hits the flange and disappears, it is possible to prevent the air level from entering the sensing portion and making the oil level inaccurate.
Further, according to the fourth aspect of the present invention, the oil pan can be attached and detached while the oil sensor is covered with the shielding member, so that the possibility of damaging the oil sensor during maintenance can be eliminated.
According to the fifth aspect of the present invention, the oil flow path is formed between the bottom wall inner surface of the oil pan and the lower end opening of the shielding member using the oil sensor fixing boss protruding from the bottom wall inner surface of the oil pan. Since the shielding member can be fixed to the oil pan above, there is no need to separately set an attachment portion only for the shielding member, and the structure can be simplified.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  The engine 1 to which the present invention is applied is, for example, an automobile diesel engine, and a box-shaped oil pan 2 having an open upper surface is coupled to the lower surface of the cylinder block 3. The oil pan 2 accommodates a balancer device 6 for reducing secondary vibration of the engine 1 from the crank pulley 5 side below the crankshaft 4 to the center. An oil sensor 7 for detecting the oil level OL of the engine oil stored in the oil pan 2 is disposed at a position adjacent to the end surface in the cylinder row direction of the balancer device 6. The oil level OL represents the oil level when the engine is idling while the vehicle is stationary on a horizontal plane. The oil level described in the claims is the oil level OL described above. Defined.

  The oil sensor 7 includes a base portion 10 that integrally includes a circuit board housing portion 8 and a wire harness connection portion 9, and a sensing portion 11 that extends upward from the center of the base portion 10. The oil sensor 7 includes a sensing portion 11 inserted into the oil pan 2 through a circular hole 12 provided in the bottom wall of the oil pan 2, and the upper surface of the base portion 10 is liquid-tightly attached to the bottom surface of the oil pan 2. After being in close contact, the oil pan 2 is fixed with a plurality of bolts B1.

  A rib 14 surrounding the base portion 10 of the oil sensor 7 and the wire harness 13 protrudes from the bottom surface of the bottom wall of the oil pan 2, and the cover plate 15 is fixed to the lower end edge of the rib 14 with a plurality of bolts B 2. Thus, the entire base portion 10 and the lower portion of the wire harness 13 are covered.

  A plurality of (three in the present embodiment) bosses 16 each having a substantially truncated cone shape are erected around a circular hole 12 (an insertion hole for the sensing portion) on the inner surface of the bottom wall of the oil pan 2. In these bosses 16, female screw holes for screwing bolts B <b> 1 for fixing the base portion 10 of the oil sensor 7 are formed from the outer surface of the bottom wall of the oil pan 2.

  The sensing unit 11 of the oil sensor 7 is a well-known one in which a detection body (not shown) is housed in a hollow case, and energizes to raise the detection body to a temperature that is, for example, 10 ° C. higher than the oil temperature. After that, the time until the temperature drops, for example, 5 ° C. is measured, and the ratio of the portion immersed in the engine oil with respect to the entire detection body is calculated from the time, and the oil level OL in the oil pan 2 is calculated from that value. Is estimated.

  In this type of oil sensor 7, the oil level in the sensing unit 11 is stored in the oil pan 2 at the lower end of the case constituting the sensing unit 11 in order to equalize the oil level in the oil pan 2. An oil inflow hole 17 for circulating the engine oil is formed, and a ventilation hole 18 for circulating air on the oil surface in the oil pan 2 is formed at the upper end of the case constituting the sensing unit 11. ing. Thereby, the inside of the sensing unit 11 has the same atmospheric pressure as that in the oil pan 2, and the oil level in the sensing unit 11 and the oil pan 2 is made equal to each other.

  However, since the oil pan 2 is filled with mist of engine oil and the counterweight provided on the crankshaft 4 scatters the oil droplets, the oil droplets enter the sensing unit 11 from the vent hole 18. there is a possibility. It is not preferable that extra oil droplets adhere to the upper oil level in the sensing unit 11 because it causes a measurement error of the oil level.

  Therefore, in the present invention, in order to prevent oil droplets from entering the sensing unit 11 from the vent hole 18, all of the portions protruding above the oil level of the sensing unit 11 and of the portion immersed under the oil level are detected. The shielding member 21 covering a part is provided.

  The shielding member 21 has a cylindrical shape with the upper end closed and the lower end opened, and a radially outward flange 22 having a generally triangular shape is provided at the lower end. The shielding member 21 is integrally fixed to the oil pan 2 by fastening each apex angle of the flange 22 to the top surface of the boss 16 having a truncated cone shape protruding from the inner surface of the bottom wall of the oil pan 2 with a bolt B3. It has become so.

  In this way, by immersing the lower end of the shielding member 21 below the oil level, the influence of the oil surface swing is suppressed from reaching the sensing unit 11. In particular, by extending the flange 22 on a plane parallel to the oil level, resistance to the movement of the engine oil in the vertical direction can be given and the oscillation of the oil level around the oil sensor 7 can be further suppressed. . At the same time, the bubbles generated in the engine oil hit the flange 22 and disappear, so that the oil surface in the sensing unit 11 can be prevented from foaming due to the bubbles entering from the oil inflow hole 17. That is, the flange 22 can favorably suppress fluctuations in the liquid level in the sensing unit 11.

  Here, the boss 16 is formed with a female screw hole for screwing the fixing bolt B1 of the oil sensor 7 from the outside of the oil pan 2, and the bolt B3 for fastening the flange 22 of the shielding member 21 from the inside of the oil pan 2 is formed. A female screw hole for screwing is provided in the boss 16 adjacent to the female screw hole. That is, the shielding member 21 is fixed by using the boss 16 projecting inside the oil pan 2 in order to provide a female screw hole for screwing the fixing bolt B1 of the oil sensor 7 from the outside of the oil pan 2. As a result, the shielding member 21 can be fixed to the oil pan 2 after the flow path of the engine oil is formed between the bottom wall inner surface of the oil pan 2 and the lower end opening of the shielding member 21. Therefore, there is no need to separately set a mounting portion only for this purpose.

  A second ventilation hole 23 for introducing the air in the oil pan 2 into the shielding member 21 is formed at the upper end of the shielding member 21. The second vent hole 23 is provided at a position where it does not overlap with the vent hole 18 of the sensing unit 11 when viewed from the outer surface of the shielding member 21, and oil droplets from the second vent hole 23 into the shielding member 21 are preferably used. Even if it enters, it does not enter the sensing unit 11.

  The present invention can be particularly effective when applied to an engine equipped with a balancer device 6 for reducing secondary vibration. The balancer device 6 includes two balancer shafts 32 a and 32 b each having an eccentric weight 31 that are linked to a crankshaft and two balancer shafts 32 a and 32 b that are linked by a linkage gear 33. The balancer shafts 32a and 32b are well-known ones configured to rotate in reverse to each other at twice the rotational speed of the crankshaft 4. When such balancer shafts 32a and 32b rotate, splashes of engine oil picked up by the eccentric weight 31 will be scattered in the oil pan 2, but by covering the sensing unit 11 with the shielding member 21, the engine Oil droplets can be reliably prevented from entering the sensing unit 11.

  The oil sensor 7 and the shielding member 21 are both attached to the oil pan 2. Accordingly, the oil pan 2 can be attached and detached while the oil sensor 7 is still covered with the shielding member 21, so that the possibility of the oil sensor 21 hitting the balancer device 6 during the maintenance work can be eliminated. .

  In the present embodiment, the second ventilation hole 23 is provided on the opposite side of the balancer device 6 with respect to a plane that passes through the axis of the shielding member 21 and is orthogonal to the axis of the balancer device 6, and passes through the sensing unit 11. The air holes 18 are oriented in a direction perpendicular to the second air holes 23 on a plane parallel to the oil level OL. In short, the second air holes 23 are located at positions where the engine oil splashed by the balancer shafts 32a and 32b is not directly applied. Needless to say, the positional relationship between the air holes 18 and 23 is not limited to the above-described form.

  In general, a baffle plate 35 is provided below the crankshaft 4. If a part of the baffle plate 35 covers the upper portion of the shielding member 21 (see FIG. 2), the upper end surface of the shielding member 21 is completely closed. Even if not, the intrusion of engine oil can be prevented. In this case, the second vent hole is unnecessary.

It is a principal part longitudinal cross-sectional view of the engine to which this invention was applied. FIG. 2 is an elevational view showing a part of the oil pan side of the engine shown in FIG. 1 along the line II-II in FIG. 1. It is a principal part top view of an oil pan.

Explanation of symbols

2 Oil pan 7 Oil sensor 11 Sensing unit 17 Oil inflow hole 18 Vent hole 21 Shield member 22 Flange 23 Second vent hole

Claims (5)

The engine oil parameters stored in the oil pan are brought into contact with the engine oil stored in the oil pan in the sensing part in which the vent hole is provided at a position protruding above the oil level and the oil inflow hole is provided at a position immersing below the oil level. An oil sensor containing a detection body that outputs a signal corresponding to
The sensor includes a shielding member that covers the entire circumference of a portion protruding above the oil level including the portion provided with the vent hole in the sensing unit, and has a lower end portion immersed under the oil level. Oil sensor.   The shielding member covers the periphery from all of the portion of the sensing unit that protrudes above the oil level to at least a part of the portion that is submerged below the oil level, and on the oil level of the shielding member. 2. The oil sensor according to claim 1, further comprising a second ventilation hole at a position that does not overlap with the ventilation hole when viewed from the outer surface of the portion projecting into the first part.   The shielding member includes a flange extending on a plane parallel to the oil surface at a position where the shielding member is immersed below the oil surface, and is fixed to the oil pan with the flange. The oil sensor according to claim 1 or 2.   The oil sensor according to any one of claims 1 to 3, wherein the oil sensor is attached to the oil pan together with the shielding member. A boss provided with a female screw hole for screwing a bolt for fastening the oil sensor from the outside of the oil pan projects from the inner surface of the bottom wall of the oil pan,
The oil sensor according to claim 4, wherein a female screw hole for screwing a bolt for fastening a flange of the shielding member from the inside of the oil pan is provided in the boss.

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