JP2008014866A - Liquid level detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid level detector capable of stably detecting the level of a liquid inside a tank. <P>SOLUTION: A liquid amount sensor 10 as a liquid level detector is equipped with a sensor body 24, attached to the side wall 18B of a washer tank 12 for storing a liquid, a first electrode 26 projecting from the sensor body 24 into the washer tank 12, and a second electrode 28 projecting from the sensor body 24 into the washer tank 12 and arranged offset, in a direction vertical to the first electrode 26, and the sensor outputs a signal, according to the existence of continuity between the first electrode 26 and the second electrode 28. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid level detection device that outputs a signal corresponding to a liquid level in a tank.

  A float type liquid level sensor for detecting the cleaning liquid level is installed in the mounting hole at the bottom of the tank to light the warning lamp when the cleaning liquid level (remaining amount) of the washer tank mounted on the vehicle is low. A configuration that is inserted and attached is known. In this technology, when the cleaning liquid level is not low, the float is in the up position and the reed switch is turned off and the warning lamp goes off.When the cleaning liquid level is low, the float is in the down position and the magnet in the float is The warning lamp is lit by turning on the reed switch.

  In such a float type liquid level sensor, the float moves following the rise and fall of the cleaning liquid level, so if the cleaning liquid in the tank shakes near the low level, the float also moves up and down, and the warning lamp turns on and off. It will be repeated. In order to prevent this, a technique is known in which an outer cylinder surrounding the float is provided while allowing the flow of the cleaning liquid to suppress the influence of the fluctuation of the cleaning liquid surface (see, for example, Patent Document 1 and Patent Document 2). .

In addition, since the liquid level sensor as described above has a structure in which the float rises and falls in the vertical direction following the cleaning liquid surface, as described above, the float moves in the direction of movement of the float with respect to the mounting hole provided in the tank bottom wall. It is inserted and attached along, and can be attached to a mounting hole having a small opening area.
Japanese Utility Model Publication No. 62-92427 Japanese Utility Model Publication No. 3-93735

  However, since the conventional technology as described above has a structure in which the liquid level sensor is attached to the mounting hole in the tank bottom wall, for example, the liquid level sensor is likely to be wetted by winding up from a water pool on the road surface. There is a risk of flooding the site. Also, when connecting the vehicle-side connector to the connector of the liquid level sensor after the tank is mounted on the vehicle, the connection work is complicated because the connector of the liquid level sensor attached to the bottom wall faces downward. There was a problem such as.

  On the other hand, it is conceivable to attach the liquid level sensor to an attachment hole formed in the side wall of the tank, but in this structure, the insertion direction of the liquid level sensor into the attachment hole does not coincide with the movement (up / down) direction of the float. This makes it difficult to align the float guide of the liquid level sensor with the direction of movement of the float, and causes malfunction due to the float being caught on the float guide.

  In view of the above fact, an object of the present invention is to obtain a liquid level detection device capable of stably detecting a liquid level in a tank.

  In order to achieve the above object, a liquid level detection device according to the first aspect of the present invention includes a main body attached to a side wall of a tank for storing a liquid, and protrudes from the main body into the tank. A first electrode; and a second electrode that protrudes into the tank from the main body and includes a portion that is offset in a vertical direction with respect to the first electrode. The first electrode and the second electrode A signal corresponding to the presence or absence of conduction with the electrode is output.

  In the liquid level detection device according to claim 1, for example, when the first and second electrodes are electrically connected by the liquid in the tank, and when the conduction between the first and second electrodes is interrupted. Based on the difference between the output signals (including ON / OFF switching), it is possible to detect whether or not the liquid level in the tank, that is, the liquid amount is greater than or equal to a predetermined value. Here, in this liquid level detection apparatus, since it is attached to the side wall of the tank, the part located outside the tank in the main body does not face downward. For this reason, for example, when the tank is mounted on a vehicle such as an automobile, it is difficult to receive water from the road surface, and for example, connector connection work after the tank is mounted can be easily performed.

  Moreover, in this liquid level detection apparatus, since the output signal is switched according to the presence or absence of conduction between the first electrode and the second electrode, in other words, there is no need for a movable part such as a float. The liquid level can be detected without being affected by the posture (accuracy). In the present liquid level detection device, the first electrode and the second electrode are offset in the vertical direction at least partially and have different height positions. In other words, the first electrode and the second electrode Since the electrode can be tied so as to intersect the liquid level in the static state, even if the liquid level fluctuates, there is a probability that the lower electrode (part) in the vertical direction is located in the liquid relative to the upper electrode (part). high. For this reason, the possibility that any of the electrodes will be separated from the liquid due to the fluctuation of the liquid level is halved. For example, an electrode positioned relatively vertically (having a part) should be set as the output signal switching liquid level. For example, it is possible to prevent the liquid level detection / non-detection from frequently switching with the fluctuation of the liquid level in the tank.

  Thus, in the liquid level detection device according to the first aspect, the liquid level in the tank can be stably detected. The present liquid level detection device may be configured such that at least a part of the first and second electrodes are located in the tank (liquid storage part thereof), and a part of the main body part is a tank together with each electrode. The structure located inside may be sufficient.

  The liquid level detection device according to a second aspect of the present invention is the liquid level detection device according to the first aspect, wherein the main body is attached by being inserted into an attachment hole formed in a side wall of the tank, Each of the first and second electrodes includes a base electrode portion protruding from the main body portion along the insertion direction of the main body portion with respect to the mounting hole.

  In the liquid level detecting device according to the second aspect, the main body portion is inserted and attached to the mounting hole provided in the tank side wall with the protruding side of the first and second electrodes as the head. Thus, the main body is attached to the tank side wall while the first and second electrodes are positioned in the tank. The main body is easy to mount because the protruding direction of each base electrode, that is, the first and second electrodes, and the direction of insertion into the mounting hole coincide.

  A liquid level detection device according to a third aspect of the present invention is the liquid level detection device according to the second aspect, wherein the base electrode portion projects in a straight line from the main body portion, and the main body portion. Are arranged along a horizontal plane in a state of being attached to the side wall.

  In the liquid level detection device according to claim 3, each base electrode portion of the first and second electrodes is in a horizontal plane, that is, in a static state in a state where the main body portion is attached to a tank held in a predetermined posture. It is located in a straight line along the liquid surface. Thereby, the first and second electrodes are likely to be in contact with the liquid in the tank at least in the longitudinal direction of the base electrode portion (at least partially contact with the liquid in the longitudinal direction).

  The liquid level detection device according to a fourth aspect of the present invention is the liquid level detection device according to the second or third aspect, wherein the first electrode extends from the base electrode portion to the main body portion of the base electrode portion. An extended electrode portion extending in a direction intersecting with the protruding direction is included.

  In the liquid level detection device according to claim 4, since the extended electrode portion extends from the base electrode portion of the first electrode, the first electrode is not in contact with the liquid even in the extending direction of the extended electrode portion. It is easy to be secured.

  The liquid level detection device according to a fifth aspect of the present invention is the liquid level detection device according to the fourth aspect, wherein the extension electrode portion is formed from an end portion of the base electrode portion opposite to the main body portion. It extends on both sides of the base electrode part so as to form a right angle with the base electrode part.

  In the liquid level detection device according to claim 5, since the extended electrode portion is provided so as to form a T shape with the base electrode portion, the first electrode portion is in contact with the liquid in two orthogonal directions. It is easy to be secured and hardly affected by the shaking of the liquid level in each direction.

  The liquid level detection device according to a sixth aspect of the present invention is the liquid level detection device according to the fourth or fifth aspect, wherein the first electrode has the base electrode portion and the extended electrode portion from the second electrode. Is also arranged on the upper side in the vertical direction.

  The liquid level detection device according to claim 6, wherein the first electrode, which has the base electrode portion and the extension electrode portion and is easily in contact with the liquid surface, has the base electrode portion and the extension electrode portion as the second electrode. Since it is placed above the base electrode part in the vertical direction, it is easy to ensure contact with the liquid at the upper electrode in the vertical direction, which is easily separated from the liquid level due to liquid level fluctuations, and the liquid level in the tank is stable. Can be detected.

  The liquid level detection device according to claim 7 is the liquid level detection device according to any one of claims 2 to 6, wherein the first electrode and the second electrode are attached to the main body. It is formed so as to be located inside the outer edge of the main body as a whole when viewed from the direction of insertion into the hole.

  In the liquid level detection device according to the seventh aspect, the first and second electrodes are prevented from interfering (hooking) with the portion around the mounting hole on the tank side wall as the main body is inserted into the mounting hole. Thereby, the assembly workability is improved and the deformation of the electrode is also prevented.

  The liquid level detection device according to an eighth aspect of the present invention is the liquid level detection device according to any one of the first to seventh aspects, wherein the first and second electrodes are surrounded and the liquid level detection device is disposed in the tank. A cylindrical portion having a communication path communicating with the space was further provided.

  In the liquid level detection device according to claim 8, for example, when the liquid in the tank is introduced into the cylindrical part through the communication path, the first and second electrodes are electrically connected, and the liquid level becomes low and becomes cylindrical. When the liquid is discharged from the part, the conduction between the first and second electrodes is interrupted. Since the cylindrical portion suppresses the vibration from being transmitted to the first and second electrodes, the liquid level detection / non-detection is frequently switched with the liquid level fluctuation in the tank. Can be prevented.

  A liquid level detection device according to a ninth aspect of the present invention is the liquid level detection device according to any one of the first to eighth aspects, wherein the tank is mounted on a vehicle and is disposed on a surface to be cleaned of the vehicle. A washer tank constituting a washer device for supplying a cleaning liquid.

  In the liquid level detection device according to the ninth aspect, the output signal is switched according to the level of the cleaning liquid in the washer tank. This signal is used to issue an alarm or the like when, for example, the amount of cleaning liquid stored is less than a predetermined amount. In this case, when the liquid level of the cleaning liquid fluctuates in the washer tank as described above, it is easy to ensure contact between the first and second electrodes and the cleaning liquid, so that frequent alarms can be prevented.

  A liquid level sensor 10 as a liquid level detection apparatus according to an embodiment of the present invention will be described based on FIGS. 1 to 4 together with a washer tank 12 to which the liquid level sensor 10 is applied.

  FIG. 3 shows a schematic overall configuration of the washer tank 12 in a front view, and FIG. 4 shows a lower portion of the washer tank 12 in a side view. The washer tank 12 is mounted on a vehicle such as an automobile and stores cleaning liquid therein. For example, the washer tank 12 constitutes a washer device that supplies cleaning liquid to a surface to be cleaned such as a front windshield glass or a lens of a headlamp. ing. In this embodiment, the washer tank 12 is configured such that the injection pipe 16 protrudes upward in the vertical direction from the upper part of the tank body 14.

  That is, the washer tank 12 has a posture in which the injection pipe 16 extends along the vertical direction above the tank body 14 as shown in FIG. In the following description, when a direction such as a vertical direction or a horizontal direction is used, it is assumed that the washer tank 12 is attached to the vehicle body in the above mounting posture (displacement of the washer tank 12 itself due to vibration of the vehicle body is ignored). In each drawing, the upper side in the vertical direction is indicated by an arrow U and the lower side in the vertical direction is indicated by an arrow L as appropriate. In addition, a direction along a horizontal plane perpendicular to the vertical direction is indicated by an arrow H.

  As shown in FIGS. 1 and 3, the tank body 14 is configured by joining a lower tank 18 and an upper tank 20. The lower tank 18 is open upward with a side wall 18B standing from the periphery of the bottom wall 18A. In the upper tank 20, the side wall 20 </ b> B is suspended from the periphery of the top wall portion 20 </ b> A and opened downward, and the shape of the opening end substantially matches the shape of the upward opening end of the lower tank 18. By joining the lower tank 18 and the upper tank 20 at the opening ends of each other, a tank main body 14 capable of storing a predetermined amount of cleaning liquid is configured.

  A recess 18 </ b> C that opens upward in the tank body 14 is formed in the bottom wall 18 </ b> A of the lower tank 18, and constitutes the lowermost part of the tank body 14. The recess 18C communicates with a suction portion (not shown) of a washer pump 22 that pumps the cleaning liquid toward the spray nozzle. The washer pump 22 is fixedly mounted across the side wall 18B of the lower tank 18 and the side wall 18D of the recess 18C that is flush with the side wall 18B. The other end of a piping hose whose one end is connected to a washer nozzle (not shown) is connected to the discharge portion 22A of the washer pump 22.

  Further, a liquid amount sensor 10 for detecting that the amount of the cleaning liquid in the tank main body 14 has become a predetermined amount or less is provided in the lower part of the tank main body 14. As shown in FIGS. 1A and 1B, the liquid amount sensor 10 includes a sensor body 24 as a main body, and a first electrode 26 and a second electrode 28 supported by the sensor body 24, respectively. It is configured to include. The liquid amount sensor 10 outputs an ON signal when the first electrode 26 and the second electrode 28 are electrically connected, and is OFF when the electrical connection between the first electrode 26 and the second electrode 28 is interrupted. It is configured to output a signal.

  The sensor body 24 formed in a substantially columnar or cylindrical shape has a flange portion 24A formed at the center portion in the axial direction, a fitting portion 24B positioned on one side in the axial direction with respect to the flange portion 24A, and a flange portion 24A. And a connector portion 24C located on the other side in the axial direction. The first electrode 26 and the second electrode 28 are each formed in a substantially rod shape, and project from the fitting portion 24B side of the sensor body 24 along the axial direction of the sensor body 24. Each of the first electrode 26 and the second electrode 28 according to this embodiment corresponds to the base electrode portion in the present invention as a whole (a portion protruding from the shell of the sensor body 24).

  The first electrode 26 and the second electrode 28 are electrically connected to output terminals 32 and 34 provided in the connector portion 24C, respectively. The liquid amount sensor 10 is configured to output the above-described ON signal or OFF signal to an automobile relay or ECU (described later) applied via a counterpart connector connected to the connector portion 24C.

  As shown in FIGS. 3 and 4, the liquid amount sensor 10 is attached to the side wall 18 </ b> B of the washer tank 12. Specifically, as shown in FIG. 1A, a mounting hole 36 is formed in the side wall 18B. The mounting hole 36 is a circular hole (not shown) having a size that allows the fitting portion 24B of the sensor body 24 to be inserted and the flange portion 24A not to be inserted, and a grommet 38 is held on the inner edge thereof. . The fitting part 24 </ b> B of the sensor body 24 is fitted to the grommet 38. That is, the grommet 38 is interposed between the fitting portion 24B of the sensor body 24 and the hole edge of the mounting hole 36 in the side wall 18B.

  When the liquid amount sensor 10 is attached to the side wall 18B, the sensor body 24 is inserted into the grommet 38 with the grommet 38 set on the side wall 18B. On the outer periphery of the fitting portion 24 </ b> B, an annular convex portion for preventing removal that bites into the grommet 38 may be formed. Further, instead of the structure in which the liquid amount sensor 10 is attached to the side wall 18B via the grommet 38, the side wall 18B inserted in the attachment hole 36 and the sensor body 24 may be welded and attached.

  As described above, the liquid amount sensor 10 is attached to the side wall 18B of the washer tank 12 so that the first electrode 26 and the second electrode 28 are positioned in the tank body 14, and the flange portion 24A is disposed outside the tank body 14 in the grommet 38. The connector portion 24C is positioned outside the tank main body 14 in contact with the positioned end surface 38A. The lower portion 18E to which the liquid amount sensor 10 is attached on the side wall 18B is a flat surface extending substantially along the vertical direction, and the sensor body 24 is inserted into the attachment hole 36 (grommet 38) along the horizontal direction. It is set as the structure. Further, since the side wall 18B extends in the vertical direction, in the liquid amount sensor 10, the first electrode 26 and the second electrode 28 are arranged in a horizontal plane in the tank body 14, that is, along the insertion direction of the sensor body 24 into the mounting hole 36. Thus, a long rod-shaped electrode is formed.

  As shown in FIGS. 1A and 1B, in the liquid amount sensor 10, the first electrode 26 is disposed on the upper side in the vertical direction with respect to the second electrode 28. That is, the first electrode 26 and the second electrode 28 are arranged offset in the vertical direction. In this embodiment, the first electrode 26 and the second electrode 28 are arranged such that the axis of the sensor body 24 is as shown in FIG. 1B, which is a view in the axial direction of the sensor body 24 (viewed in the direction of arrow A in FIG. 1A). It arrange | positions so that it may be located on the centerline CL in alignment with a perpendicular direction by direction view.

  That is, the plane passing through both the first electrode 26 and the second electrode 28 coincides with the center line CL in the plane extending in the vertical direction and the longitudinal direction of the first electrode 26 and the second electrode 28 (FIG. 1B). Which is substantially perpendicular to the liquid level S1 (horizontal plane) in the static state of the cleaning liquid stored in the tank body 14. The liquid amount sensor 10 is prevented from rotating with respect to the side wall 18B by a stopper or the like (not shown) so as to maintain the positional relationship between the first electrode 26 and the second electrode 28.

  Further, in the liquid amount sensor 10, the vertical position of the first electrode 26 located on the upper side in the vertical direction is set to the liquid level to be detected. Here, the cleaning liquid is a liquid having water as a main component and conductivity, and the liquid amount sensor 10 outputs an ON signal as described above when the first electrode 26 and the second electrode 28 are conducted by the cleaning liquid. . On the other hand, the liquid amount sensor 10 is used when either the first electrode 26 or the second electrode 28 is separated from the cleaning liquid or when the cleaning liquid becomes discontinuous between the first electrode 26 and the second electrode 28. Is disconnected from the first electrode 26 and the second electrode 28, and outputs an OFF signal.

  Therefore, in a static state where the cleaning liquid level Sl is along the horizontal plane, the liquid level sensor 10 is configured so that the liquid level sensor 10 has the first electrode 26 and the second electrode 26 as long as the cleaning liquid level Sl is higher than the lowermost portion 26A of the first electrode 26. When both of the electrodes 28 come into contact with the cleaning liquid and output an ON signal, and the liquid level Sl of the cleaning liquid falls below the lowermost portion 26A of the first electrode 26, the liquid amount sensor 10 becomes conductive when the first electrode 26 is separated from the cleaning liquid. It is shut off and outputs an OFF signal. That is, as described above, the vertical position of the first electrode 26 is set to the liquid level to be detected, and when the cleaning liquid is consumed and the liquid level Sl of the cleaning liquid falls below the lowermost part 26A of the first electrode 26, the liquid The output signal of the quantity sensor 10 is switched from the ON signal to the OFF signal. The liquid level to be detected is a liquid level (low level) corresponding to the predetermined amount to be replenished with the remaining amount of cleaning liquid in the tank body 14.

  The liquid amount sensor 10 is electrically connected to a relay provided in a circuit for turning on the warning indicator or a warning ECU that controls turning on / off of the warning indicator. A relay or warning ECU on the vehicle side is provided on an instrument panel arranged so as to be visible from the driver's seat when an OFF signal is input from the liquid amount sensor 10, that is, when the remaining amount of cleaning liquid is less than a predetermined amount. The warning indicator (warning light) is turned on by supplying power.

  Next, the operation of the present embodiment will be described.

  In the liquid amount sensor 10 having the above configuration, when the amount of the cleaning liquid in the washer tank 12 is larger than a predetermined amount, the liquid level Sl of the cleaning liquid is located above the lowermost portion 26A of the first electrode 26, The first electrode 26 and the second electrode 28 are made conductive by the cleaning liquid and output an ON signal. The warning ECU receiving the ON signal maintains the warning indicator in the off state.

  For example, when the front windshield glass or the headlamp is cleaned and the remaining amount of the cleaning liquid decreases and falls below a predetermined amount, the liquid level Sl of the cleaning liquid falls below the lowermost portion 26A of the first electrode 26 and the first electrode 26 It reaches the non-contact state with the cleaning liquid. Then, the conduction between the first electrode 26 and the second electrode 28 is interrupted, and the liquid amount sensor 10 outputs an OFF signal. Upon receiving the OFF signal, the warning ECU turns on the warning indicator and maintains the warning indicator in the lit state during the period of receiving the OFF signal.

  By the way, in the washer tank 12 mounted on the automobile, road surface input, engine vibration, and the like accompanying traveling may be transmitted to cause a phenomenon that the liquid level Sl of the cleaning liquid fluctuates (waves). This shaking causes the cleaning liquid to contact and separate from the first electrode 26 and the second electrode 28.

  Here, in the liquid amount sensor 10, since the first electrode 26 and the second electrode 28 are disposed so as to be offset in the vertical direction, in the vicinity of the lower surface of the cleaning liquid surface Sl where the remaining amount of the cleaning liquid becomes a predetermined amount. Even when the liquid level S1 of the cleaning liquid fluctuates, the second electrode 28 disposed vertically below the liquid level to be detected (low level of the cleaning liquid) is located in the cleaning liquid (contact with the cleaning liquid). Is likely to be maintained).

  As a result, as shown in FIG. 2 (A), the liquid level sensor 10 switches the output signal due to the contact and separation between the liquid surface Sl of the cleaning liquid that mainly fluctuates and the first electrode 26. Compared to the configuration in which a pair of electrodes are arranged in parallel with the power level, one electrode is separated from the cleaning liquid despite the remaining amount of the cleaning liquid being a predetermined amount or more (the liquid level of the cleaning liquid is higher than a low level). The possibility of losing is almost halved. For this reason, in the automobile (washer device) to which the liquid amount sensor 10 is applied, the warning indicator is prevented from being frequently turned on due to the shaking of the liquid surface Sl of the cleaning liquid.

  Further, as shown in FIG. 2B, since the first electrode 26 is long in a predetermined direction, it is easy to ensure contact with the liquid surface Sl of the cleaning liquid that swings in the longitudinal direction (a part of the longitudinal direction is the cleaning liquid). Likely to come in contact). Moreover, since the longitudinal direction of the first electrode 26 is a direction along the horizontal plane, in other words, the first electrode 26 extends along the liquid surface Sl (the reference plane of shaking) of the cleaning liquid in a static state. There is a high possibility that any part of the first electrode 26 flower in the hand direction comes into contact with the cleaning liquid. In particular, it is easier to ensure contact between the cleaning liquid level Sl and the first electrode 26 swaying at a short wavelength due to vibrations transmitted from the automobile body, and the warning indicator is frequently lit by the shaking of the cleaning liquid level Sl. Is more effectively prevented.

  Further, since the liquid amount sensor 10 is attached to the side wall 18B of the washer tank 12, the connector portion 24C does not face downward as in the configuration attached to the bottom wall portion 18A. For this reason, in the liquid amount sensor 10, it is difficult to receive water due to winding from a water pool accompanying traveling of an automobile in which the washer tank 12 is mounted on the connector portion 24C, and the connection work of the mating connector to the connector portion 24C is easy. Can be done.

  In particular, the liquid amount sensor 10 is formed on the side wall 18B because the insertion direction of the sensor body 24 into the mounting hole 36 and the protruding direction of the first electrode 26 and the second electrode 28 from the sensor body 24 coincide. The washer tank 12 is attached so that the first electrode 26 and the second electrode 28 are positioned in the position 14 by simply inserting the sensor body 24 in the axial direction into the attachment hole 36 formed, and this attachment operation As a result, the rod-shaped first electrode 26 and the second electrode 28 do not interfere with the surface around the mounting hole 36 in the side wall 18B, so that the workability of assembling the liquid amount sensor 10 to the washer tank 12 is improved. Deformation of the first electrode 26 and the second electrode 28 is prevented.

  In the liquid amount sensor 10, the ON signal and the OFF signal are switched according to the presence / absence of conduction between the first electrode 26 and the second electrode 28, in other words, no moving parts such as a float are required. The liquid level can be detected without being affected by the mounting posture (accuracy) with respect to the tank. For this reason, the liquid amount sensor 10 can be applied to the side wall 18B which can obtain the above-described effects without causing the problem of malfunction due to the attachment to the side wall 18B, which has been a concern with the float type liquid amount sensor. Installation was able to be realized.

  As described above, the liquid level sensor 10 according to the first embodiment can stably detect the level of the cleaning liquid in the washer tank 12.

(Other embodiments)
Next, another embodiment of the present invention will be described. Parts and portions that are basically the same as those in the first embodiment or the previous configuration are denoted by the same reference numerals as those in the first embodiment or the previous configuration, and the description thereof is omitted. May be omitted.

(Second Embodiment)
FIG. 5 shows a liquid level sensor 40 according to the second embodiment of the present invention in a side view corresponding to FIG. As shown in this figure, the liquid amount sensor 40 is different in the vertical position and the horizontal position perpendicular to the longitudinal direction instead of the first electrode 26 and the second electrode 28 arranged on the center line CL. It differs from the liquid amount sensor 10 according to the first embodiment in that it includes the first electrode 42 and the second electrode 44 that are arranged. That is, in the liquid quantity sensor 40, the plane passing through both the first electrode 42 and the second electrode 44 is a plane extending in the longitudinal direction of the imaginary straight line L1 and the first electrode 26 and the second electrode 28 (see FIG. 5, a surface that coincides with the virtual straight line L <b> 1), and intersects the liquid surface Sl (horizontal surface) in the static state of the cleaning liquid stored in the tank body 14. The other configuration of the liquid amount sensor 40 is the same as the corresponding configuration of the liquid amount sensor 10.

  Therefore, the liquid sensor 40 according to the second embodiment can obtain the same effect by the same operation as the liquid sensor 10 according to the first embodiment. Note that the liquid amount sensor 40 can be grasped as a single unit having the same configuration as the liquid amount sensor 10 as having a different mounting posture with respect to the washer tank 12.

(Third embodiment)
FIG. 6 is a perspective view of a liquid amount sensor 50 according to the third embodiment of the present invention. As shown in this figure, the liquid amount sensor 50 includes a first electrode 52 and a second electrode 54 each formed in a flat bar shape instead of the first electrode 26 and the second electrode 28 each formed in a round bar shape. In the point provided, it differs from the liquid quantity sensor 10 which concerns on 1st Embodiment. Other configurations of the liquid amount sensor 50 are the same as the corresponding configurations of the liquid amount sensor 10.

  Therefore, the liquid sensor 50 according to the third embodiment can obtain the same effect by the same operation as that of the liquid sensor 10 according to the first embodiment.

(Fourth embodiment)
FIG. 7 is a perspective view showing a liquid amount sensor 60 according to the fourth embodiment of the present invention. As shown in this figure, the liquid amount sensor 60 includes a first electrode 62 formed in a substantially T shape in plan view, instead of the first electrode 26 corresponding to the base electrode portion as a whole. This is different from the liquid amount sensor 10 according to the first embodiment.

  The first electrode 62 includes a base electrode portion 64 that is elongated along the axial direction of the sensor body 24, that is, the insertion direction into the mounting hole 36, and an extension in which the center portion in the longitudinal direction is connected to the tip of the base electrode portion 64. The crossing electrode part 66 as an electrode part is formed as a main part. The longitudinal direction of the intersecting electrode portion 66 is a direction perpendicular to the base electrode portion 64 (a direction orthogonal to the longitudinal direction of the base electrode portion 64).

  Further, as shown in FIG. 8A, the length a of the cross electrode portion 66 is set shorter than the diameter b of the mounting hole 36. In this embodiment, as shown in FIG. 8B, when the inner edge of the attachment hole 36 along the upper edge 66A of the cross electrode portion 66 in a state where the sensor body 24 is attached to the side wall 18B is a chord C, the cross electrode portion 66 is used. Is set to be shorter than the length c of the string C. Thereby, the liquid amount sensor 60 is configured to prevent the cross electrode portion 66 from being caught on the surface of the side wall 18B around the mounting hole 36 when the sensor body 24 is inserted into the mounting hole 36 along the axial direction. ing. Note that the length of the cross electrode portion 66 may be determined so as not to interfere with the grommet 38 based on the inner edge (inner diameter) of the grommet 38 instead of the mounting hole 36.

  Furthermore, as shown in FIGS. 9A and 9B, the liquid amount sensor 60 is configured so that the base electrode portion 64 and the cross electrode portion 66 of the first electrode 62 extend along the same horizontal plane. The sensor body 24 is attached to the side wall 18B. In this attached state, the second electrode 28 is located on the lower side in the vertical direction of the base electrode portion 64 of the first electrode 62. That is, the plane passing through both the base electrode portion 64 and the second electrode 28 coincides with the center line CL in the vertical direction and the plane extending in the longitudinal direction of the base electrode portion 64 and the second electrode 28 (FIG. 8B). Which is substantially perpendicular to the liquid level S1 (horizontal plane) in the static state of the cleaning liquid stored in the tank body 14.

  The other configuration of the liquid amount sensor 60 is the same as the corresponding configuration of the liquid amount sensor 10. The liquid amount sensor 60 can be grasped as a configuration in which a cross electrode portion 66 is added to the liquid amount sensor 10.

  Therefore, the liquid sensor 60 according to the fourth embodiment can obtain the same effect by the same operation as the liquid sensor 10 according to the first embodiment. Further, since the liquid amount sensor 60 is provided with the crossed electrode portion 66, the liquid of the cleaning liquid in the direction as shown in FIG. 9B, which is different from the shaking direction of the liquid surface Sl of the cleaning liquid shown in FIG. Even when the surface Sl is shaken (especially when the wavelength is short), the contact between the liquid surface Sl and the first electrode 62 is more easily secured, and the warning indicator is frequently lit by the shake of the liquid surface Sl of the cleaning liquid. Is more effectively prevented.

  In the fourth embodiment, the example in which the first electrode 62 is arranged along the horizontal plane is shown. However, the present invention is not limited to this, and for example, the cross electrode portion 66 is arranged to be inclined with respect to the horizontal plane. You may be made to do. In this case, for example, the lowest part of the cross electrode part 66 and the second electrode 28 can be made isotopic at the liquid level to be detected.

  Further, instead of the first electrode 62 formed in a T shape, an L-order first electrode in which the tip side of the base electrode portion 64 is bent may be provided.

(Fifth embodiment)
FIG. 10 is a front view in which a liquid level sensor 70 according to the fifth embodiment is partially cut away. As shown in this figure, the liquid amount sensor 70 is different from 10 according to the first embodiment in that it includes a cover case 72 as a cylindrical body surrounding the first electrode 26 and the second electrode 28.

  The cover case 72 is formed in a bottomed cylindrical shape in which the end of the cylindrical wall 72A opposite to the sensor body 24 is closed by the bottom wall 72B, and the first electrode 26 and the second electrode 28 in the sensor body 24 are formed. The sensor body 24 is coaxially connected to the end surface of the sensor. The cover case 72 is formed with a window portion 74 and a hole portion 76 as communication paths for allowing the cleaning liquid to flow in and the cleaning liquid to flow out. As a result, the liquid level in the cover case 72 is configured to match the liquid level in the tank body 14.

  In this embodiment, as shown in FIG. 11, each of the window portions 74 is formed in a rectangular shape, and a pair is provided so as to pass through the cylindrical wall 72 </ b> A of the cover case 72 and open in the direction opposite to the substantially horizontal direction. ing. On the other hand, the hole 76 is formed in a substantially circular shape, and is provided in the cylindrical wall 72A of the cover case 72 so as to open downward.

  Other configurations of the liquid amount sensor 70 are the same as the corresponding configurations of the liquid amount sensor 10. The cover case 72 may be formed integrally with the sensor body 24, or may be configured by joining a separate body to the sensor body 24. In the case of integral molding, the first electrode 26, the second electrode 28, and the output terminals 32 and 34 are insert-molded while holding the mold. In addition, the window part 74 and the cover case 72 are formed using a slide core.

  Therefore, the liquid sensor 70 according to the fifth embodiment can obtain the same effect by the same operation as the liquid sensor 10 according to the first embodiment. Further, since the liquid amount sensor 70 includes the cover case 72, the fluctuation of the liquid surface Sl of the cleaning liquid in the tank body 14 is difficult to be transmitted to the first electrode 26 and the second electrode 28 (installation site). In particular, it is easy to ensure that the first electrode 26 is in contact with the cleaning liquid even with respect to large fluctuations in wavelength as shown in FIG. For this reason, in an automobile (washer device) to which the liquid amount sensor 70 is applied, it is more effectively prevented that the warning indicator is frequently turned on due to the shaking of the liquid surface Sl of the cleaning liquid.

  Similar effects can also be obtained by a configuration in which the cylindrical wall portion 100 is erected from the bottom wall portion 18A as shown in FIG. 12B as a comparative example. In the configuration according to this comparative example, There is concern about the deterioration of the moldability and releasability of the lower tank 18, and even if the cylindrical wall portion 100 formed as a separate member is joined, the mass of the washer tank 12 as a whole increases and the amount of resin used increases. Problems arise. On the other hand, since the liquid amount sensor 70 has a structure in which the cover case 72 is provided on the sensor body 24, it does not affect the moldability and releasability of the lower tank 18, and is small, that is, increases in mass and resin amount. Therefore, the lighting of the warning indicator due to the fluctuation of the liquid level Sl of the cleaning liquid can be suppressed.

(Sixth embodiment)
FIG. 13 is a perspective view of a liquid amount sensor 80 according to the sixth embodiment. As shown in this figure, the liquid amount sensor 80 is provided with a cylindrical cover case 82 that does not have a bottom wall corresponding to the bottom wall 72B, instead of the cover case 72, according to the fifth embodiment. Is different.

  The cover case 82 has an opening end on the side opposite to the sensor body 24 and a window portion 84 as a communication path. For this reason, the cover case 82 is configured to be easily formed integrally with the sensor body 24 (the mold structure is simple). The other configuration of the liquid amount sensor 80 is the same as the corresponding configuration of the liquid amount sensor 70.

  Accordingly, the liquid amount sensor 80 according to the sixth embodiment also has the same effect (including the same effect by the same operation as the liquid amount sensor 10) by the same operation as the liquid amount sensor 70 according to the fifth embodiment. ) Can be obtained.

(Seventh embodiment)
FIG. 14 is a perspective view of a liquid amount sensor 90 according to the seventh embodiment. As shown in this figure, the liquid amount sensor 90 is a fifth embodiment in that it includes a cover case 92 having no window portion 74 instead of the cover case 72 having a pair of window portions 74 that open in the horizontal direction. Different from 70 according to form.

  The cover case 92 has a cylindrical wall 72A and a bottom wall 72B, and a hole portion 94 is formed as a communication path that opens upward in the cylindrical wall 72A. The hole portion 94 is a circular hole having a diameter similar to that of the hole portion 76, and is configured to have a sufficiently small opening area with respect to the window portion 74. The cover case 92 is formed separately from the sensor body 24, and an open end 92A opposite to the bottom wall 72B of the cylindrical wall 72A is an end surface 24D from which the first electrode 26 and the second electrode 28 of the sensor body 24 protrude. It is joined to. Other configurations of the liquid amount sensor 90 are the same as the corresponding configurations of the liquid amount sensor 70.

  Accordingly, the liquid amount sensor 90 according to the seventh embodiment also includes the same effect (including the same effect by the same operation as the liquid amount sensor 10) by the same operation as the liquid amount sensor 70 according to the fifth embodiment. ) Can be obtained.

  In each of the above-described embodiments, the liquid amount sensors 10, 40, 50, 60, 70, 80, and 90 according to the present invention are applied to the washer tank 12, but the present invention is not limited to this. First, the present invention can be applied to liquid level detection of various liquids having conductivity.

  In each of the above-described embodiments, the sensor body 24 is inserted into the mounting hole 36 and attached to the side wall 18B. However, the present invention is not limited to this. For example, the sensor body is provided on the side wall 18B. It may be held in a concave portion, or may be fixed to the side wall 18B by fastening means, clamping means or the like. In these cases, for example, only the first electrode 26 and the second electrode 28 may be protruded into the tank body 14.

  Furthermore, in each of the above-described embodiments, the lowermost part of the pair of electrodes disposed on the upper side in the vertical direction (the lowermost part 26A of the first electrode 26, etc.) is made to coincide with the liquid level to be detected. Although an example has been shown, the present invention is not limited to this. For example, in a configuration in which a pair of electrodes has an isotope portion in the vertical direction, the isotope portion (the lowermost portion thereof) coincides with the liquid level to be detected. be able to.

It is a figure which shows the liquid quantity sensor which concerns on the 1st Embodiment of this invention, Comprising: (A) is a front view, (B) is a side view. It is a figure which shows the liquid quantity sensor which concerns on the 1st Embodiment of this invention, Comprising: (A) is a side view which shows the contact state of the liquid level and electrode which shakes, (B) is the contact of the liquid level and electrode which shakes. It is a front view which shows a state. 1 is a front view of a washer tank to which a liquid amount sensor according to a first embodiment of the present invention is applied. It is a side view of the washer tank lower part to which the liquid quantity sensor concerning a 1st embodiment of the present invention was applied. It is a side view which shows the liquid quantity sensor which concerns on the 2nd Embodiment of this invention. It is a perspective view which shows the liquid quantity sensor which concerns on the 3rd Embodiment of this invention. It is a perspective view which shows the liquid quantity sensor which concerns on the 4th Embodiment of this invention. It is a figure which shows the liquid quantity sensor which concerns on the 4th Embodiment of this invention, Comprising: (A) is a top view, (B) is a side view. It is a figure which shows the liquid quantity sensor which concerns on the 4th Embodiment of this invention, Comprising: (A) is a front view which shows the contact state of the liquid level and electrode which shakes, (B) is the contact of the liquid level and electrode which shakes. It is a side view which shows a state. It is a side view which shows the liquid quantity sensor which concerns on the 5th Embodiment of this invention. It is a perspective view which shows the liquid quantity sensor which concerns on the 5th Embodiment of this invention. (A) is a side view which shows the contact state of the electrode of the liquid quantity sensor which concerns on the 5th Embodiment of this invention, and the liquid surface which shakes, (B) shows the comparative example with the 5th Embodiment of this invention. It is a side view. It is a perspective view which shows the liquid quantity sensor which concerns on the 6th Embodiment of this invention. It is a disassembled perspective view which shows the liquid quantity sensor which concerns on the 7th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Liquid level sensor (liquid level detection apparatus), 12 ... Washer tank (tank), 18B ... Side wall (side wall part of tank), 24 ... Sensor body (main body part), 26 ... -1st electrode (1st electrode, base electrode part), 28 ... 2nd electrode (2nd electrode, base electrode part), 36 ... Mounting hole, 40 * 50 * 60 * 70 * 80 * 90 ... Liquid level sensor (liquid level detection device), 42.52 ... First electrode (first electrode, base electrode part), 44.54 ... Second electrode (second electrode, base) Electrode part), 62 ... 1st electrode (1st electrode), 64 ... Base electrode part, 66 ... Crossing electrode part (extension electrode part), 72, 82, 92 ... Cover case (Cylindrical part), 74/84 ... Window part (communication path), 76/94 ... Hole part (communication path)

Claims (9)

A main body attached to the side wall of the tank for storing liquid;
A first electrode protruding from the main body into the tank;
A second electrode that protrudes from the main body into the tank and includes a portion that is vertically offset with respect to the first electrode;
And a liquid level detection device that outputs a signal corresponding to the presence or absence of conduction between the first electrode and the second electrode. The main body is attached by being inserted into an attachment hole formed in the side wall of the tank,
2. The liquid level detection device according to claim 1, wherein each of the first and second electrodes includes a base electrode portion protruding from the main body portion along an insertion direction of the main body portion with respect to the attachment hole.   The liquid level detection device according to claim 2, wherein the base electrode portion is projected in a straight line from the main body portion and is disposed along a horizontal plane in a state where the base electrode portion is attached to the side wall.   4. The liquid level detection according to claim 2, wherein the first electrode includes an extended electrode portion extending from the base electrode portion in a direction intersecting with a protruding direction of the base electrode portion with respect to the main body portion. apparatus.   The said extended electrode part is extended from the edge part on the opposite side to the said main-body part in the said base electrode part to the both sides of this base electrode part so that it may make a right angle with this base electrode part. Liquid level detection device.   6. The liquid level detection device according to claim 4, wherein the first electrode has the base electrode portion and the extended electrode portion arranged on the upper side in the vertical direction with respect to the second electrode.   The first electrode and the second electrode are formed so as to be located inside the outer edge of the main body as a whole when viewed from the insertion direction of the main body into the mounting hole. The liquid level detection device according to any one of the above.   8. The liquid level detection device according to claim 1, further comprising a cylindrical portion surrounding the first and second electrodes and having a communication path communicating with a space in the tank. 9.   The liquid level detection device according to any one of claims 1 to 8, wherein the tank is a washer tank that is mounted on a vehicle and constitutes a washer device that supplies a cleaning liquid to a surface to be cleaned of the vehicle.

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