JP2017198602A - Liquid level detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid level detection device in which a float can be satisfactorily displaced with simple structure even when a liquid container where a liquid is retained or a liquid level is tilted, and which is hardly affected by disturbance of the liquid level.SOLUTION: An oil level detection device 12 is provided that comprises: a guide shaft 13 extending vertically; a float 14 having a shaft hole 26 through which the guide shaft 13 is inserted and displaced in the axial direction of the guide shaft 13 following the liquid level of a lubricating oil retained in an oil pan; and a reed switch 20 for detecting the position of the float 14 relative to the guide shaft 13. In the oil level detection device 12, the float 14 comprises a disc-like float center portion 22 having a float lower surface 25 orthogonal to the shaft center P of the guide shaft 13 and an annular float peripheral portion 23 provided spanning the outer circumference of the float center portion 22 and extending in an outward inclined manner from the outer circumference toward the radial outside of the float center portion 22.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a liquid level detecting device, and more particularly to a liquid level detecting device for detecting the level of oil in an oil pan of an engine mounted on an automobile or fuel in a fuel tank.

  As a conventional liquid level detection device, for example, the oil level detection device disclosed in Patent Document 1 can be cited. The oil level detection device disclosed in Patent Document 1 is used in an internal combustion engine, and detects the level of the level of engine oil stored in the internal combustion engine. The oil level detection device includes a housing having a cylindrical shaft portion, a float that forms a center hole, and a reed switch that detects a position of the float that is displaced up and down along the cylindrical shaft portion inserted into the center hole. Yes. The oil level detection device is suspended and supported by a support mechanism on a sensor stay provided in the internal combustion engine. By this support mechanism, the housing is allowed to tilt with respect to the sensor stay.

Japanese Patent Laid-Open No. 2015-219062

  However, the oil level detection device disclosed in Patent Document 1 requires a support mechanism for allowing the housing to tilt with respect to the sensor stay, and there is a problem that the structure of the oil level detection device is complicated. In addition, this type of oil level detection device is susceptible to the influence of the oil level fluctuation, such as the housing being liable to tilt sensitively following the oil level disturbance.

  The present invention has been made in view of the above problems, and an object of the present invention is to displace the float satisfactorily with a simple structure even when the liquid container storing the liquid or the liquid level is inclined. In addition, the present invention is to provide a liquid level detecting device that is hardly affected by the disturbance of the liquid level.

  In order to solve the above problems, the present invention has a guide shaft extending vertically and a shaft hole through which the guide shaft is inserted, and follows the liquid level of the liquid stored in the liquid container. In the liquid level detecting apparatus, comprising: a float that is displaced in an axial direction of a shaft; and a detection unit that detects a position of the float with respect to the guide shaft, the float is a bottom surface of the float that is orthogonal to the axis of the guide shaft A disc-shaped float central part having an annular float outer peripheral part provided over the outer periphery of the float central part and extending upwardly from the outer periphery of the float central part toward the radially outer side. It is characterized by providing.

  In the present invention, even if the liquid container or the liquid level is inclined, a part of the outer periphery of the float is buried in the liquid level and the float obtains buoyancy. For this reason, it is possible to prevent erroneous detection that the float cannot capture the liquid level and is insufficient in an appropriate amount, and the liquid level can be detected appropriately. No means for tilting the liquid level detection device is required, and the structure is simple. Moreover, the float outer peripheral part is equipped with the performance (wave surpassing performance) which surpasses the wave of a liquid level, and a float is hard to be influenced by the disordered liquid level. Therefore, even when the liquid level is waved and disturbed, a stable displacement of the float with respect to the guide shaft is maintained.

Further, in the liquid level detecting device, the outer peripheral portion of the float has an inclined outer peripheral surface inclined with respect to the lower surface of the float, and an angle of the inclined outer peripheral surface with respect to the lower surface of the float is in a range of 10 to 45 °. It is good also as the composition set up.
In this case, the angle of the inclined outer peripheral surface is set in the range of 10 to 45 °, so that it can cope with the inclination of the liquid surface that occurs when the vehicle turns and the maximum inclination of the liquid container that occurs when the vehicle tilts. Can do.

  In the liquid level detecting device, the float center portion has a float upper surface, and the float upper surface has a downward gradient from the outer periphery toward the shaft hole or a groove depth from the outer periphery toward the shaft hole. It is good also as a structure which has the groove | channel which increases.

  In this case, the liquid that has flowed from the outer peripheral side of the float to the float upper surface flows into the shaft hole through the float upper surface having a gradient at the center of the float or a groove provided in the float upper surface, and the liquid stored in the liquid container through the shaft hole Join. For this reason, liquid does not accumulate on the upper part of the float, and the function of the float is not impaired.

  According to the present invention, even when the liquid container storing the liquid or the liquid level is inclined, the float can be displaced favorably with a simple structure, and the liquid level detection that is not easily affected by the disturbance of the liquid level. An apparatus can be provided.

It is a longitudinal cross-sectional view which shows the outline | summary of the oil pan provided with the oil level detection apparatus which concerns on 1st Embodiment. It is a longitudinal cross-sectional view of the oil level detection apparatus which concerns on 1st Embodiment. It is a perspective view of the float of the oil level detection apparatus concerning a 1st embodiment. (A) is a longitudinal cross-sectional view which shows the oil level detection apparatus in the state in which the liquid level of lubricating oil inclines, (b) is a vertical cross section in which the oil level detection apparatus in the state in which the liquid level of lubricating oil inclines FIG. It is a longitudinal cross-sectional view of the float with which the oil level detection apparatus which concerns on 2nd Embodiment is provided.

(First embodiment)
Hereinafter, an oil level detection device as a liquid level detection device according to a first embodiment will be described with reference to the drawings. In this embodiment, an oil level detection device as a liquid level detection device will be described. The oil level detection device of the present embodiment is provided in an oil pan of an engine mounted on a vehicle.

  As shown in FIG. 1, an oil pan 11 is attached to the bottom of the engine 10. The oil pan 11 stores lubricating oil which is supplied to each part in the engine 10 and used for lubrication and cooling of the sliding part. The oil pan 11 corresponds to a liquid container. Lubricating oil stored in the oil pan 11 is pumped up by an oil pump (not shown) and supplied to each part in the engine 10. The oil pump is driven as the engine 10 is operated. Lubricating oil used for lubrication and cooling of the sliding portion flows down to the oil pan 11 through an oil circulation passage (not shown) in the engine 10 and is stored in the oil pan 11 again. An appropriate amount (hereinafter referred to as “appropriate amount”) of lubricating oil is stored in the oil pan 11 for proper lubrication and cooling of the engine 10 with the lubricating oil. Since the liquid level of the lubricating oil in the oil pan 11 fluctuates due to the inclination of the road surface and the acceleration / deceleration of the vehicle, the inclination of the road surface and the acceleration / deceleration of the vehicle are factors that cause the liquid level to fluctuate. The level of the lubricating oil fluctuates regardless of the longitudinal direction and the lateral direction of the vehicle.

  The oil pan 11 is provided with an oil level detection device 12. The oil level detection device 12 detects the level of the lubricating oil in order to monitor whether or not the amount of lubricating oil stored in the oil pan 11 is an appropriate amount. The oil level detection device 12 is provided at a position where it does not interfere with a crankshaft (not shown) provided in the engine 10.

  The oil level detection device 12 includes a guide shaft 13 extending vertically and a float 14 that follows the liquid level of the lubricating oil and is displaced in the axial direction of the guide shaft 13. The guide shaft 13 is fixed to the inner wall surface of the oil pan 11 via a bracket 15. The oil level detection device 12 is electrically connected to the controller C. The controller C is connected to the warning light E, and has a function of turning on the warning light E when the lubricating oil falls below an appropriate amount based on a signal from the oil level detection device 12.

  As shown in FIG. 2, the guide shaft 13 includes a small-diameter shaft portion 16 that allows the float 14 to move, and a large-diameter shaft portion 17 that has a larger diameter than the small-diameter shaft portion 16. The small diameter shaft portion 16 extends downward from the lower end of the large diameter shaft portion 17. The guide shaft 13 includes a step 18 between the small diameter shaft portion 16 and the large diameter shaft portion 17. The step 18 is a stopper that defines the uppermost position of the float 14. In the vicinity of the lower end of the small-diameter shaft portion 16, a protruding piece 19 that protrudes in the radial direction of the axis P of the guide shaft 13 is provided. The projecting piece 19 prevents the float 14 from coming out of the guide shaft 13 and defines the lowest position of the float 14.

  The guide shaft 13 has a bottomed cylindrical shape, and a reed switch 20 as a detection unit is accommodated in a space in the guide shaft 13. The reed switch 20 has a function of detecting the position of the float 14 and opening and closing the contact. Specifically, the switch is turned on or off when magnetic flux flows through the reed switch 20 by the permanent magnet 21 provided in the float 14. The reed switch 20 extends from the lower end of the small diameter shaft portion 16 to the vicinity of the lower end of the large diameter shaft portion 17.

  Next, the float 14 will be described. The float 14 is formed of an oil-resistant foamed resin having a specific gravity smaller than that of the lubricating oil. The float 14 includes a disk-shaped float central portion 22 and an annular float outer peripheral portion 23 provided over the outer periphery of the float central portion 22. The float center part 22 and the float outer peripheral part 23 are integrally formed. The float center portion 22 has a shaft hole 26 penetrating from the float upper surface 24 to the float lower surface 25 at the center. The small diameter shaft portion 16 of the guide shaft 13 is inserted into the shaft hole 26. An annular permanent magnet 21 is built in the float center portion 22 so as to surround the shaft hole 26.

  As shown in FIG. 3, a groove 27 is formed in the float upper surface 24 in the radial direction of the axis P of the guide shaft 13 so as to connect the outer periphery of the float upper surface 24 and the shaft hole 26. The groove depth of the groove 27 increases from the outer periphery of the float upper surface 24 toward the shaft hole 26. A plurality of grooves 27 are radially formed in the float upper surface 24 in the circumferential direction. The groove 27 guides the lubricating oil flowing into the float upper surface 24 to the shaft hole 26 and prevents the lubricating oil from being stored in the float upper surface 24.

  The float outer peripheral portion 23 provided over the outer periphery of the float central portion 22 extends while inclining from the outer periphery of the float central portion 22 toward the radially outer side of the float central portion 22. Accordingly, the float outer peripheral portion 23 has an inclined outer peripheral surface 28 that extends from the float lower surface 25 and is inclined radially outward with respect to the float lower surface 25. The float outer peripheral portion 23 has an inclined inner peripheral surface 29 that extends from the float upper surface 24 and that inclines toward the radially outer side upward with respect to the float upper surface 24. The float outer peripheral portion 23 has an outer end surface 30 that connects the inclined outer peripheral surface 28 and the inclined inner peripheral surface 29. The outer end surface 30 is a surface orthogonal to the inclined outer peripheral surface 28 and the inclined inner peripheral surface 29.

  Incidentally, in the present embodiment, the inclination angle θ of the inclined outer peripheral surface 28 with respect to the float lower surface 25 is set to 45 °. The inclination angle θ is set based on a preset maximum inclination angle of the lubricating oil surface or the maximum inclination angle of the vehicle, and is preferably set in the range of 10 to 45 °. The inclination angle of the inclined inner peripheral surface 29 with respect to the float upper surface 24 is also set to 45 ° similarly to the inclination angle θ. Therefore, the thickness H of the float outer peripheral portion 23 is constant, and the thickness H is set based on the buoyancy required by the float outer peripheral portion 23.

  The float outer peripheral portion 23 has a shape in which it is easy to obtain buoyancy from the liquid level so that the liquid level L of the lubricating oil is correctly detected even when the level of the lubricating oil is inclined. Further, the float 14 includes the float center portion 22 and the float outer peripheral portion 23, so that the float 14 as a whole has a reduced weight. In FIG. 2, for convenience of explanation, the boundary between the float center portion 22 and the float outer peripheral portion 23 is indicated by a one-dot chain line.

  By the way, if the diameter of the conventional float is enlarged so that the float can capture the liquid level even if the oil pan 11 or the liquid level is inclined, the float can obtain buoyancy. However, if the float diameter is simply enlarged, the radial space required for the float also increases. On the other hand, in this embodiment, since the float outer peripheral part 23 was provided, the maximum diameter of the float 14 is larger than the conventional float. However, the float 14 realizes a float that can capture the liquid level without enlarging the maximum diameter of the float 14 so much as compared with the case of simply enlarging the diameter of the float.

  Next, the operation of the oil level detection device 12 of this embodiment will be described. In a state where the level of the lubricating oil and the vehicle are not inclined, as shown in FIG. 2, a part of the float 14 is submerged in the lubricating oil so that the level of the lubricating oil and the float lower surface 25 are parallel to each other. When the lubricating oil level and the vehicle are not inclined, the position of the float 14 varies according to the lubricating oil level L. When the lubricating oil is reduced, the liquid level L is lowered and the float 14 is lowered. When the amount of lubricating oil increases, the liquid level L increases and the float 14 rises. The reed switch 20 opens and closes the contact by detecting the position of the float 14 with respect to the guide shaft 13 by the magnetic flux of the permanent magnet 21.

  When the float 14 is displaced to a position below the proper amount of lubricating oil, the controller C turns on the warning lamp E in response to the OFF signal of the reed switch 20. When the float 14 is displaced to a position that is an appropriate amount of lubricating oil, the ON signal of the reed switch 20 is transmitted to the controller C, and the warning lamp E is not lit.

  When the vehicle turns on a curve or suddenly starts or stops, the liquid level of the lubricating oil is inclined rather than horizontal due to the inertial force. As shown in FIG. 4A, when the liquid level of the lubricating oil is inclined, a part of the float outer peripheral portion 23 is submerged in the lubricating oil. Therefore, even when the liquid level is inclined, the float 14 obtains buoyancy and is displaced up and down with respect to the guide shaft 13 according to the liquid level L. At this time, when the inclination angle of the liquid surface is smaller than the inclination angle of the float outer peripheral portion 23, the lubricating oil does not flow into the upper surface of the float 14.

  When the vehicle travels on an inclined surface, the oil pan 11 is inclined as the vehicle body is inclined. Even if the oil pan 11 is tilted, the liquid level of the lubricating oil does not tilt. As shown in FIG. 4B, when the oil pan 11 is inclined, a part of the float outer peripheral portion 23 is submerged in the lubricating oil. Accordingly, even when the oil pan 11 is inclined, the float 14 obtains buoyancy and is displaced with respect to the guide shaft 13 according to the liquid level L. At this time, when the inclination angle of the oil pan 11 is smaller than the inclination angle of the float outer peripheral portion 23, the lubricating oil does not flow into the upper surface of the float 14.

  By the way, the liquid level of the lubricating oil may be disturbed. In the present embodiment, since the inclined outer peripheral surface 28 is provided, the float outer peripheral portion 23 has a performance (wave surpassing performance) that surpasses the wave of the liquid surface, and the float 14 is hardly affected by the disturbed liquid surface. Accordingly, even when the liquid level of the lubricating oil is turbulent and disturbed, the stable displacement of the float 14 with respect to the guide shaft 13 is maintained. In some cases, the liquid surface swells violently and the lubricating oil gets over the float outer peripheral portion 23 and flows into the float upper surface 24. In this case, the flowing lubricating oil flows through the groove 27 to the shaft hole 26 and merges with the lubricating oil stored in the oil pan 11 through the shaft hole 26, so that the lubricating oil does not collect on the float upper surface 24.

The oil level detection device 12 according to the present embodiment has the following operational effects.
(1) Even if the liquid level of the oil pan 11 or the lubricating oil is inclined, a part of the float outer peripheral portion 23 is buried in the liquid level and the float 14 obtains buoyancy, so that the liquid level L is properly detected. Can do. There is no need for means for inclining the entire oil level detection device 12 in accordance with the inclination of the oil pan 11 or the level of the lubricating oil, and the structure of the oil level detection device 12 is simple. Moreover, since the structure of the float 14 is simple, it is possible to replace the float of the existing oil level detection device with the float 14.

(2) Since the angle of the inclined outer peripheral surface 28 with respect to the float lower surface 25 is set to 45 °, the maximum inclination of the oil pan 11 generated when the lubricating oil is inclined when the vehicle is turned or when the oil pan 11 is inclined when the vehicle is inclined. Can respond.

(3) Since the float center portion 22 includes the groove 27, the lubricating oil that has flowed from the outer peripheral side of the float 14 to the float upper surface 24 flows to the shaft hole 26 through the groove 27 provided on the float upper surface 24, and oil flows through the shaft hole 26. The lubricating oil stored in the pan 11 joins. For this reason, lubricating oil does not accumulate on the float upper surface 24, and the function of the float 14 is not impaired.

(Second Embodiment)
Next, a second embodiment will be described. The second embodiment differs from the first embodiment in the configuration of the float. In the present embodiment, the description of the first embodiment is used for the same configuration as the first embodiment, and the reference numerals are used in common.

  The oil level detection device 40 according to this embodiment includes a float 41 shown in FIG. The float 41 has a float center part 42 and a float outer peripheral part 23. The float center portion 42 includes a float upper surface 43, a float lower surface 44, and a shaft hole 45. The shaft hole 45 penetrates from the float upper surface 43 to the float lower surface 44 at the center of the float central portion 42. An annular permanent magnet 21 is built in the float center portion 42 so as to surround the shaft hole 45.

  The float upper surface 43 has a downward gradient from the outer periphery of the float center portion 42 toward the shaft hole 45. Therefore, the thickness of the float center part 42 decreases from the outer periphery of the float center part 42 toward the shaft hole 45. Due to the slope of the float upper surface 43, even if the lubricating oil flows over the float outer peripheral portion 23 and flows into the float upper surface 43, the lubricating oil that has flowed is concentrated toward the shaft hole 45 by the float upper surface 43.

  According to this embodiment, there exists an effect equivalent to the effect (1), (2) of 1st Embodiment. Furthermore, since the float center part 42 includes the float upper surface 43 having a gradient, the lubricating oil flowing into the float upper surface 43 from the outer peripheral side of the float 41 is concentrated toward the shaft hole 45 through the float upper surface 43 having the gradient. The collected lubricating oil merges with the lubricating oil stored in the oil pan 11 through the shaft hole 45. For this reason, lubricating oil does not accumulate on the float upper surface 43, and the function of the float 41 is not impaired.

  The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the gist of the invention. For example, the following modifications may be made.

In the above embodiment, the oil level detection device that detects the liquid level of the lubricating oil stored in the oil pan is exemplified as the liquid level detection device, but this is not restrictive. The liquid level detection device may be, for example, a fuel level detection device that detects the liquid level of the fuel stored in the fuel tank. If the liquid level detection target is the liquid stored in the liquid container, Good.
In the above embodiment, the angle of the inclined outer peripheral surface with respect to the float lower surface is set to 45 °, but this is not restrictive. The angle of the inclined outer peripheral surface with respect to the float lower surface is preferably set in the range of 10 to 45 °. What is necessary is just to set the angle of the inclination outer peripheral surface with respect to a float lower surface according to the maximum inclination angle of the liquid level assumed by turning of a vehicle, an uphill, etc., and the maximum inclination angle of a liquid container.
In the above embodiment, the maximum diameter of the float is larger than that of the conventional float, but this is not restrictive. For example, the maximum diameter of the float may be the same as that of a conventional float. In this case, the radial space required for the float is the same as that of the conventional float.
In the above embodiment, a step is provided on the guide shaft and the uppermost position of the float is defined. However, this is not restrictive. The guide shaft may have a structure that defines only the lowest position of the float and does not have a step. In this case, a liquid level detecting device that transmits an off signal only when the float is displaced to the lowest position may be used.
In the above embodiment, the case where the liquid container or the liquid surface is inclined in a specific direction is exemplified, but the inclination direction of the liquid container or the liquid surface is 360 ° including front and rear, right and left, and is not particularly limited.

DESCRIPTION OF SYMBOLS 10 Engine 11 Oil pan 12, 40 Oil level detection apparatus 13 Guide shaft 14, 41 Float 22, 42 Float center part 23 Float outer peripheral part 24, 43 Float upper surface 25, 44 Float lower surface 26, 45 Shaft hole 27 Groove 28 Inclined outer peripheral surface 29 Inclined inner peripheral surface 30 Outer end surface P Axis center H Thickness θ Inclination angle L Liquid level

Claims (3)

A guide shaft extending vertically,
A float having a shaft hole through which the guide shaft is inserted and following the liquid level of the liquid stored in the liquid container and displacing in the axial direction of the guide shaft, and detection for detecting the position of the float with respect to the guide shaft A liquid level detecting device comprising:
The float is
A disc-shaped float central portion having a float lower surface perpendicular to the axis of the guide shaft;
A liquid level detecting device, comprising: an annular float outer peripheral portion that is provided over the outer periphery of the float central portion and extends upwardly from the outer periphery of the float central portion toward the radially outer side. . The float outer peripheral portion has an inclined outer peripheral surface inclined with respect to the lower surface of the float,
The liquid level detecting device according to claim 1, wherein an angle of the inclined outer peripheral surface with respect to the lower surface of the float is set in a range of 10 to 45 °. The float center has a float top surface,
3. The liquid level according to claim 1, wherein the upper surface of the float has a groove having a downward gradient from the outer periphery toward the shaft hole or a groove whose groove depth increases from the outer periphery toward the shaft hole. Detection device.

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