JP2016090300A - Liquid detector, compressor and air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capacitance liquid detector capable of preventing a detection error of liquid level height of a liquid such as lubricant, and detecting capacitance accurately, a compressor having the liquid detector, and an air conditioner having the compressor.SOLUTION: A detection element part 10 of a liquid detection unit 1 is configured so that, a facing gap between a pair of electrode plates 40S, 40mS is set to become wide, and a facing gap between a pair of electrode plates 40mL, 40L is set to become narrow. By a detection signal corresponding to the pair of electrode plates 40S, 40mS having the wide facing gap, presence/absence of a liquid, namely, liquid level height is detected. By a detection signal corresponding to the pair of electrode plates 40mL, 40L having the narrow facing gap, capacitance is detected, for detecting a ratio of impurities contained in the liquid.SELECTED DRAWING: Figure 2

Description

  The present invention relates to, for example, a capacitance type liquid detector used for detecting a liquid level of a lubricating oil of a compressor used in an air conditioner, a compressor having the liquid detector, and the compression The present invention relates to an air conditioner equipped with a machine.

  The air conditioner includes an outdoor heat exchanger and an indoor heat exchanger, and an expansion valve and a compressor provided therebetween. In the refrigeration cycle of an air conditioner, for example, the liquid refrigerant that has passed through the outdoor heat exchanger becomes gaseous by the expansion valve, and the temperature is lowered to cool air, which is led to the indoor heat exchanger. The gaseous refrigerant that has transferred heat (low temperature) to the indoor air by the indoor heat exchanger is compressed by the compressor to a high temperature / high pressure state, and heat (high temperature) is given to the outdoor air by the outdoor heat exchanger. It becomes liquid again by transferring.

  As a compressor used in such an air conditioner, there is a compressor adopting a rotary method or a scroll method. For example, in a rotary compressor disclosed in Patent Document 1, a compression unit having a cylinder in which a working chamber is formed and an annular piston accommodated in the working chamber is disposed in a tank-like compressor housing. The annular piston is rotated while a part of the outer peripheral surface is in contact with the peripheral wall surface of the working chamber, whereby the refrigerant introduced into the working chamber is compressed.

  In the compressor disclosed in Patent Document 1, lubricating oil is accommodated in the compressor housing for lubrication of sliding parts such as cylinders and pistons and sealing (sealing) of minute gaps. And if this lubricating oil becomes less than a predetermined amount for some reason, it will hinder the operation of the compressor, so it is necessary to monitor the amount of lubricating oil. For example, Patent Document 2 discloses a sensor that can be used for monitoring the amount of such lubricating oil.

  As shown in FIG. 14, the sensor disclosed in Patent Document 2 (indicated by reference numeral 901 in the figure) is parallel to the ends of a pair of conductive pins 904 attached to the substrate body 902 with a space between each other. A pair of arranged strip-shaped electrode plates 905 are attached. And since the electrostatic capacitance between the conductive pins 904 changes depending on the presence or absence of the lubricating oil between the pair of electrode plates 905, by providing this sensor 901 at an appropriate height in the compressor casing, It can be detected whether the amount is equal to or greater than a predetermined amount.

JP 2012-207585 A JP 2013-92491 A

  The conventional sensor described above detects the presence or absence of lubricating oil between a pair of electrode plates by a change in electrostatic capacity. However, if the facing distance between the pair of electrode plates is too narrow, the lubricating oil is reduced in the compressor. However, the lubricating oil may remain adhered between the pair of electrode plates, and in fact, there is a possibility that the oil level is detected as a normal level even when the oil level is low. Further, if the gap between the electrode plates is increased in order to solve this problem, there is a problem that the area of the electrode plate must be increased in order to obtain a desired capacitance, and the sensor itself is increased in size.

  Accordingly, the present invention provides a capacitance type liquid detector capable of accurately detecting the capacitance while preventing erroneous detection of the liquid level of a liquid such as lubricating oil, a compressor having the liquid detector, And it aims at providing the air conditioner provided with this compressor.

  The liquid detector according to claim 1 is a liquid detector that detects a liquid by a capacitance between a plurality of electrode plates, and the plurality of electrode plates at least have a pair of electrodes with a facing interval as a first interval. A first electrode pair made of a plate and a second electrode pair made of a pair of electrode plates having an opposing interval that is a second interval narrower than the first interval are configured.

  The liquid detector according to claim 2, wherein the liquid detector is used for detecting a liquid contained in the housing, and the wall is formed so as to close a through hole provided in a wall portion of the housing. And a plurality of conductive terminals protruding from one surface of the base so that at least a part thereof is disposed in the housing, and the plurality of electrode plates are Each of the plurality of conductive terminals is attached to the part of the corresponding conductive terminal so as to be arranged parallel to each other along the base.

  The liquid detector according to claim 3 is the liquid detector according to claim 1 or 2, wherein each of the plurality of electrode plates is formed in a disc shape or a regular polygon plate shape. And

  The compressor according to claim 4 is a compressor having a casing, a compression section provided in the casing, and a liquid detection section that detects lubricating oil accommodated in the casing. The part is configured to include the liquid detector according to any one of claims 1 to 3.

  The air conditioner according to claim 5 is an air conditioner including a refrigerant circuit including an indoor heat exchanger, an outdoor heat exchanger, an expansion valve, and a compressor, wherein the compressor is the compression according to claim 4. It is composed of a machine.

  According to the first, fourth, and fifth aspects of the present invention, the first electrode pair having a large distance between the opposing electrodes is capable of cutting off the liquid, so that the liquid surface height of the liquid such as lubricating oil can be increased by the first electrode pair. Can be detected without erroneous detection, and a desired capacitance can be obtained with the second electrode pair having a narrow opposing interval, so that the capacitance can be detected with high accuracy.

  According to the invention described in claim 2, the plurality of electrode plates are respectively attached to a part of the corresponding conductive terminals among the plurality of conductive terminals so as to be arranged in parallel with each other along the base. Yes. Since it did in this way, a plurality of electrode plates do not protrude greatly in the axial direction of the conductive terminal from the conductive terminal, and the moment (or load) applied to the conductive terminal due to, for example, vibration can be suppressed. The load concentrated on the portion where the terminal is attached to the base can be reduced. As a result, the mounting space can be reduced, and failure due to breakage can be suppressed. Also, by providing three or more conductive terminals parallel to each other with respect to one electrode plate, the second moment of section in the plane parallel to the electrode plate is increased, resulting in a robust structure.

  According to the invention described in claim 3, each of the plurality of electrode plates is formed in a disc shape or a regular polygon plate shape. For this reason, for example, in a configuration in which a plurality of electrode plates are formed in a band plate shape, an attachment angle when the base is attached to the housing (the direction of penetration of the through hole of the housing is a rotation axis) If there is a variation in the rotation angle), the height at which the liquid contacts the plurality of electrode plates also varies, so there may be variations in detection accuracy, but the plurality of electrode plates are disc-shaped or regular polygonal. By being formed in a plate shape, the height at which the liquid contacts the plurality of electrode plates can be made substantially constant regardless of the mounting angle, and variations in detection accuracy can be suppressed.

It is a front view of the liquid detection unit which has a detection element part as a liquid detector which concerns on 1st Embodiment of this invention. It is sectional drawing which follows the XX line of FIG. It is a rear view of the detection element part which the liquid detection unit of FIG. 1 has. It is a front view of the detection control part which the liquid detection unit of FIG. 1 has. It is a figure which shows the outline of the electric circuit of the liquid detection unit of FIG. It is sectional drawing of the detection element part as a liquid detector which concerns on 2nd Embodiment of this invention. It is a rear view of the detection element part of FIG. It is a figure which shows the outline of the electric circuit of the liquid detection unit of FIG. It is a front view of the detection element part as a liquid detector which concerns on 3rd Embodiment of this invention. It is sectional drawing which follows the XX line of FIG. It is a top view of the detection element part of FIG. It is sectional drawing of the compressor which concerns on one Embodiment of this invention. It is a figure which shows schematic structure of the air conditioner which concerns on one Embodiment of this invention. It is a perspective view of the conventional liquid level sensor.

(Embodiment of liquid detector)
Below, the liquid detector which concerns on embodiment of this invention is demonstrated with reference to FIGS. FIGS. 1-5 shows the liquid detection unit which has a detection element part as a liquid detector of 1st Embodiment. For example, the liquid detection unit is attached to a side wall of a casing of a compressor, which will be described later, and is used to detect the level of the lubricating oil contained in the casing and the degree of contamination of impurities in the lubricating oil. It is done.

  FIG. 1 is a front view of a liquid detection unit having a detection element section according to the first embodiment of the present invention. 2 is a cross-sectional view taken along line XX of FIG. FIG. 3 is a rear view of the detection element unit included in the liquid detection unit of FIG. FIG. 4 is a front view of a detection control unit included in the liquid detection unit of FIG. FIG. 5 is a diagram showing an outline of an electric circuit of the liquid detection unit of FIG.

  As shown in FIGS. 1 to 4, this liquid detection unit (indicated by reference numeral 1 in the figure) has a detection element unit 10 as a liquid detector and a detection control unit 50 (FIG. 2). . The detection element unit 10 and the detection control unit 50 are configured to be fitted to each other as a pair of connectors.

  The detection element unit 10 includes a base 20, a plurality of conductive terminals 30, and four electrode plates 40.

  The base 20 is made of, for example, a metal such as stainless steel, and integrally includes a base main body portion 21, a cylindrical portion 22, and a flange portion 23, and a plurality of conductive materials described later. A hermetic glass 24 for fixing the terminal 30 is provided.

  The base main body 21 is formed in a disc shape. The cylindrical portion 22 is provided so as to protrude from one surface 21 a of the base body 21 so as to be coaxial with the base body 21. A plurality of through holes 21c penetrating the one surface 21a and the other surface 21b are formed at a location inside the cylindrical portion 22 in the base main body portion 21. The flange portion 23 is provided over the entire peripheral surface 21 d of the base main body portion 21 so as to protrude in the radial direction of the base main body portion 21. An attachment surface 23a facing the same direction as the other surface 21b of the base main body portion 21 in the flange portion 23 is an annular flat surface, and is attached to the case 502 of the compressor 101 to be described later. It surrounds the through hole 503a provided in the side wall portion 503 as a “wall portion” and is arranged so as to be in close contact with the outer surface of the side wall portion 503. The hermetic glass 24 is fixed in the plurality of through holes 21c.

  The plurality of conductive terminals 30 are made of, for example, a conductive metal such as a nickel alloy, and are each formed in a rod shape that extends straight. Each of the plurality of conductive terminals 30 is inserted through the corresponding through hole 21c, and is fixedly attached to the base body 21 while being electrically insulated from the base body 21 by the hermetic glass 24. Yes. In order to fix the conductive terminal 30 to the base body portion 21, another insulating material may be used instead of the hermetic glass 24. Each of the plurality of conductive terminals 30 is arranged so that each part 31 protrudes perpendicularly from the other surface 21 b of the base body 21, and the other part 32 protrudes perpendicularly from the bottom surface in the cylindrical part 22. Yes. The other part 32 of each conductive terminal 30 is brought into contact with the female terminal of the detection control unit 50 as a male terminal when fitted with the detection control unit 50 described later.

  In this embodiment, twelve conductive terminals 30 are included, and four types of lengths are included. Specifically, three of the plurality of conductive terminals are formed to be the longest (indicated by 30 mL in the figure), and three are formed to be the second longest (indicated by 30 L in the figure). Are formed to be the second shortest (indicated by reference numeral 30S in the figure), and three are formed to be the shortest (indicated by reference numeral 30mS in the figure). The three conductive terminals 30mL, the three conductive terminals 30L, the three conductive terminals 30S, and the three conductive terminals 30mS are staggered in the circumferential direction so as to be the vertices of a regular dodecagon when viewed from the front. Is arranged. And each three terminals are arrange | positioned so that it may space apart at an angle of 120 degrees in the circumferential direction. The plurality of conductive terminals 30 (30 mL, 30 L, 30 S, and 30 mS) are fixed to the base body 21 so that the other portions 32 have the same length. A part 31 of the terminal 30mL, a part 31 of the three conductive terminals 30L, a part 31 of the three conductive terminals 30S, and a part 31 of the three conductive terminals 30mS have different lengths. Has been.

  The four electrode plates 40 are made of, for example, a conductive metal such as stainless steel, and are formed in the same disc shape. The outermost electrode plate 40mL of the four electrode plates 40 is fixedly attached to the tip of each part 31 of the three conductive terminals 30mL. The second outer electrode plate 40L is fixedly attached to the tip of each of the three conductive terminals 30L described above. The second inner electrode plate 40S is fixedly attached to the tip of each of the three conductive terminals 30S described above. The innermost electrode plate 40mS is fixedly attached to the tip of each part 31 of the three conductive terminals 30mS described above.

  A through hole 40a through which the three conductive terminals 30mL are inserted is provided at a position corresponding to the three conductive terminals 30mL in the electrode plate 40L. Each through hole 40a is formed so that the conductive terminal 30mL and the electrode plate 40L do not contact each other. Further, through holes 40a through which the six conductive terminals 30mL and 30L are inserted are provided at positions corresponding to the six conductive terminals 30mL and 30L in the electrode plate 40S. Each through hole 40a is formed so that the conductive terminals 30mL, 30L and the electrode plate 40S do not contact each other. Further, through holes 40a through which these nine conductive terminals 30mL, 30L, and 30S are inserted are provided at positions corresponding to the nine conductive terminals 30mL, 30L, and 30S in the electrode plate 40mS. Each through hole 40a is formed so that the conductive terminals 30mL, 30L, and 30S do not contact the electrode plate 40mS. Each through hole 40a may be covered with an insulating material in a state where the conductive terminals 30mL, 30L, and 30S are inserted.

  Each electrode plate 40 is attached to each conductive terminal 30 by, for example, welding or brazing. Thus, by attaching one electrode plate 40mL and the other electrode plate 40L to the tips of the part 31 of the conductive terminal 30mL and the part 31 of the conductive terminal 30L having different lengths, the electrode plate 40mL , 40L are arranged parallel to each other with a space therebetween. Further, by attaching one electrode plate 40S and the other electrode plate 40mS to the tips of the part 31 of the conductive terminal 30S and the part 31 of the conductive terminal 30mS having different lengths, the electrode plates 40S and 40mS are attached. Are arranged in parallel and spaced from each other. The electrode plates 40 mL, 40 L, 40 S, and 40 mS are also arranged in parallel with the mounting surface 23 a of the flange portion 23. As described above, each electrode plate 40 is disposed at a right angle to the corresponding conductive terminal 30 and is disposed along the other surface 21b of the base body 21 in parallel with the other surface 21b. Yes.

  The detection control unit 50 includes a housing 60, a case 70, and a control board 80.

  The housing 60 is made of, for example, a synthetic resin, and integrally includes a housing main body 61, a cylindrical portion 62, and a substrate housing portion 63, and further includes a seal member 64. Yes.

  The housing main body 61 is formed in a disc shape. The cylindrical portion 62 is provided so as to protrude from one surface 61 a of the housing main body 61 so as to be coaxial with the housing main body 61. The cylindrical part 62 has an outer diameter substantially the same as the inner diameter of the cylindrical part 22 so that the cylindrical part 62 is accommodated in the cylindrical part 22 of the detection element part 10 when fitted, and its height is substantially equal to the depth of the cylindrical part 22. Are the same. The cylindrical portion 62 is formed with terminal holes 62b that open to locations corresponding to the plurality of conductive terminals 30 on the end face 62a and accommodate female terminals (not shown). The substrate housing portion 63 is provided on the other surface 61 b of the housing main body 61 so as to protrude in a square tube shape. The substrate accommodating portion 63 may be of any shape as long as it can accommodate a control substrate 80 to be described later, such as a cylindrical shape.

  The seal member 64 is formed in an annular shape using, for example, silicone rubber or the like, and is partially embedded in one surface 61 a of the housing main body 61 so as to surround the cylindrical portion 22. The seal member 64 is crushed by the end surface 22a of the cylindrical portion 22 of the detection element unit 10 when fitted, and seals (seal) between the detection element unit 10 and the detection control unit 50.

  The case 70 is made of, for example, a synthetic resin, and integrally includes a cylindrical peripheral wall portion 71 and a bottom wall portion 72 that closes one end of the peripheral wall portion 71.

  The inner diameter of the peripheral wall 71 is substantially the same as the outer diameter of the cylindrical portion 22 so as to accommodate the cylindrical portion 22 of the detection element portion 10 when fitted. Further, a locking claw (not shown) that locks into a locking receiving hole (not shown) formed on the outer peripheral surface of the cylindrical portion 22 when fitted is formed on the inner peripheral surface of the peripheral wall portion 71 so as to protrude. Yes. The bottom wall portion 72 is formed with a fitting hole 72a formed in substantially the same shape (in the present embodiment, a square shape) as the planar view shape of the substrate housing portion 63 so that the substrate housing portion 63 can be fitted therein. Has been.

  The control board 80 is an electronic board in which various electronic components constituting a detection circuit for detecting capacitance are mounted on a printed board. The control board 80 is housed and fixed in the board housing portion 63, and is connected to a host control device (not shown) through the lead wire 85. The control board 80 is connected to a female terminal (not shown) accommodated in the terminal hole 62b, and in a state where the female terminal is in contact with the other part 32 (that is, a male terminal) of the conductive terminal 30, The capacitance between the electrode plates 40 mL and 40 L and the capacitance between the other pair of electrode plates 40 S and 40 mS are detected, and detection signals corresponding to the respective capacitances are output through the lead wires 85. It is configured. For example, the control board 80 detects a capacitance based on a time constant, a resonance frequency in a resonance circuit, and the like, and outputs a voltage signal (detection signal) that changes according to the magnitude of the capacitance.

  The detection element unit 10 and the detection control unit 50 are fitted closer to each other from the state shown in FIG. 2, so that the conductive terminal 30 (male terminal) of the detection element unit 10 and the housing 60 of the detection control unit 50 are included. The liquid detection unit 1 is configured to output a detection signal corresponding to the capacitance that changes in accordance with the liquid state between the pair of electrode plates 40. Here, the “liquid state” includes, for example, the ratio of impurities mixed in the liquid in addition to the presence or absence of the liquid.

  As shown in FIG. 5, the sensing element unit 10 can be regarded as two capacitors that store electric charges between the pair of electrode plates 40 mL and 40 L and between the pair of electrode plates 40 S and 40 mS, respectively. And the liquid detection unit 1 detects the electrostatic capacitance between a pair of electrode plates 40mL and 40L and the electrostatic capacitance between a pair of electrode plates 40S and 40mS, respectively, and two according to the detected electrostatic capacitance. Species detection signal is output. Based on this detection signal, the presence or absence of liquid at the height at which the detection element unit 10 is attached, that is, the liquid level can be detected. In addition, the ratio of impurities mixed in the liquid can be detected based on the capacitance value indicated by the detection signal. The electrode plates 40mL and 40mS are connected to a ground terminal (frame ground) indicated by “GND”, and the electrode plates 40L and 40S are connected to a signal terminal indicated by “+”.

  Here, as shown in FIG. 2, the facing distance (first distance) between the pair of electrode plates 40S, 40mS is wide, and the facing distance (second distance) between the pair of electrode plates 40mL, 40L is narrow. . In other words, in the plurality of electrode plates 40, the pair of electrode plates 40S and 40mS having the opposing interval as the first interval constitutes a “first electrode pair”, and the opposing interval is the second narrower than the first interval. The pair of electrode plates 40mL, 40L having the interval of "constitutes a" second electrode pair ". Note that the facing distance between the innermost electrode plate 40mS and the other surface 21b of the base main body 21 is wider than the facing distance (first distance) between the pair of electrode plates 40S and 40mS.

  And the presence or absence of a liquid, ie, a liquid level height, is detected with the detection signal corresponding to a pair of electrode plate 40S and 40mS (1st electrode pair) with a large opposing space | interval. Thereby, in this embodiment, it is possible to detect a lack of oil in the compressor. Note that the compressor is stopped when oil shortage is detected.

  Further, the ratio of impurities mixed in the liquid is detected based on detection signals corresponding to the pair of electrode plates 40mL, 40L (second electrode pair) having a narrow facing interval. In this embodiment, the ratio of impurities is detected as the relative dielectric constant of the oil inside the compressor. Thereby, it is determined how much refrigerant and oil are mixed in the compressor.

  As described above, since the pair of electrode plates 40S and 40mS having a large opposing distance is used for detecting the presence or absence of the liquid, when the liquid runs out, the liquid is surely provided between the pair of electrode plates 40S and 40mS. Furthermore, the liquid is surely lost from between the electrode plate 40mS and the other surface 21b, and the absence of liquid can be reliably detected. Further, in order to detect the ratio of impurities (relative dielectric constant of oil), the pair of electrode plates 40mL and 40L having a small facing distance are used, so that the capacitance can be detected with high accuracy. For this reason, the ratio of impurities (relative permittivity of oil) can be detected with high accuracy. In addition, when calculating | requiring the ratio of an impurity (relative dielectric constant of oil) from this electrostatic capacitance, the liquid level detected by a pair of electrode plates 40S and 40mS, ie, the liquid level between electrode plates 40mL and 40L The capacitance is converted into the ratio of impurities in accordance with the height.

  In addition, since the electrode plates 40L and 40S connected to the signal terminal (+) are sandwiched between the electrode plates 40mL and 40mS connected to the ground terminal (GND), the influence of floating charges on the base body 21 and the like is affected. Capacitance can be detected accurately without receiving.

  Next, the operation of the liquid detection unit 1 of the first embodiment described above will be described.

  For example, as shown in FIG. 12, the detection element unit 10 of the liquid detection unit 1 is attached to a side wall portion 503 as a “wall portion” along the vertical direction in a casing 502 of the compressor 101 described later. Specifically, a circular through hole 503a that is larger than the outer diameter of the base main body portion 21 of the detection element portion 10 and smaller than the outer diameter of the flange portion 23 is formed in the side wall portion 503 of the housing 502. A part 31 of the plurality of conductive terminals 30 and the four electrode plates 40 are inserted into the housing 502 from the through hole 503a, and the entire mounting surface 23a of the flange portion 23 is brought into contact with the outer surface of the side wall portion 503. And after welding the flange part 23 to the side wall part 503 and plugging the through hole 503a, the detection control part 50 is fitted to the detection element part 10.

  At this time, the four electrode plates 40 of the detection element unit 10 are arranged in parallel to each other along the vertical direction in the housing 502. Therefore, for example, as compared with a configuration in which the electrode plate 905 has a strip shape and extends toward the inside of the housing as in the conventional configuration shown in FIG. In addition, the load concentrated on the portion of each conductive terminal 30 supported by the hermetic glass 24 is reduced.

  Further, the four electrode plates 40 and the mounting surface 23a of the flange portion 23 are disposed in parallel to each other. Therefore, even when the base 20 is attached to the side wall portion 503 with a deviation in the rotation direction about the axis, that is, when the attachment angle of the base 20 is different, the side wall portion 503 along which the attachment surface 23a extends along the vertical direction. The four electrode plates 40 are also arranged along the vertical direction.

  Further, the four electrode plates 40 are formed in a disc shape. Therefore, for example, in the case of the configuration in which the four electrode plates 40 are formed in a band plate shape, when the base 20 is attached to the side wall portion 503 in a rotational direction centered on the axis, that is, the base If there is a deviation in the mounting angle of 20, the height in contact with the liquid in the housing 502 differs depending on the degree of deviation, but because of the disc shape, there is a deviation in the rotational direction of the attachment. However, the height in contact with the liquid is constant.

  As described above, according to the present embodiment, the correspondence among the plurality of conductive terminals 30 is such that the four electrode plates 40 are arranged in parallel to each other along the vertical direction in the casing 502 of the compressor 101. The conductive terminal 30 is attached to a part 31 disposed in the housing 502. As a result, the four electrode plates 40 do not protrude greatly to the inside of the housing 502, and the conductive terminal 30 is attached to the base 20, that is, the portion supported by the hermetic glass 24. The concentrated load can be reduced. As a result, the mounting space can be reduced, and failure due to breakage can be suppressed.

  Further, the four electrode plates 40 are arranged in parallel with the mounting surface 23 a of the flange portion 23. Thus, even when there is a variation (shift) in the mounting angle when the base 20 is mounted on the housing 502, the four electrode plates 40 are surely arranged along the vertical direction. For this reason, it is possible to suppress variation in detection accuracy due to a difference in liquid breakage (hardness of remaining liquid) between the four electrode plates 40.

  Each of the four electrode plates 40 is formed in a disc shape. Thus, for example, in the configuration in which the four electrode plates 40 are formed in a band plate shape, if there is a variation (shift) in the mounting angle when the base 20 is mounted on the housing 502, the liquid However, the height of contact with the four electrode plates 40 also varies, so that the detection accuracy may also vary. However, since the four electrode plates 40 are formed in a disc shape, the liquid is The height in contact with the four electrode plates 40 can be made constant regardless of the mounting angle, and variations in detection accuracy can be suppressed.

  In the above-described embodiment, the configuration includes the four electrode plates 40, but is not limited thereto. FIG. 6 is a cross-sectional view of a detection element unit as a liquid detector according to the second embodiment of the present invention. FIG. 7 is a rear view of the detection element portion of FIG. FIG. 8 is a diagram showing an outline of an electric circuit of the liquid detection unit of FIG. In the second embodiment, the detection element unit 10 </ b> A is configured to have three electrode plates 40. This detection element unit 10A has nine conductive terminals 30 and includes three types of lengths. That is, three of the plurality of conductive terminals are formed long (indicated by reference numeral 30L in the figure), the other three from these three are formed short (indicated by reference numeral 30M in the figure), and the remaining three terminals Is further shortened (indicated by reference numeral 30S in the figure). The conductive terminals 30L, 30M, and 30S are sequentially arranged in the circumferential direction so as to be the apexes of a regular hexagon as viewed from the front. The plurality of conductive terminals 30 (30L, 30M, 30S) are fixed to the base body 21 so that the lengths of the other portions 32 thereof are the same, whereby the respective conductive terminals 30L, 30M are fixed. , 30S have different lengths 31 from each other. One electrode plate 40L among the three electrode plates 40 is fixedly attached to the tip of each of the three conductive terminals 30L described above, and the other one electrode plate 40M is: The other three conductive terminals 30M are fixedly attached to the tips of the respective parts 31, and the remaining one electrode plate 40S is attached to the tips of the respective parts 31 of the remaining three conductive terminals 30S. It is fixedly attached to. Thereby, a space is provided between the electrode plate 40L and the electrode plate 40M, and between the electrode plate 40M and the electrode plate 40S, and they are arranged in parallel to each other.

  In the second embodiment, as shown in FIG. 6, the facing distance (first distance) between the pair of electrode plates 40S, 40M is wide, and the facing distance (second distance) between the pair of electrode plates 40M, 40L is as follows. It is narrower. That is, the electrode plate 40M is a common electrode, and the pair of electrode plates 40S and 40M having a first interval as the opposing interval constitutes a “first electrode pair”, and the opposing interval is narrower than the first interval. The pair of electrode plates 40M and 40L having the second interval constitutes a “second electrode pair”. Note that the facing distance between the innermost electrode plate 40S and the other surface 21b of the base body 21 is wider than the facing distance (first distance) between the pair of electrode plates 40S and 40M.

  As shown in FIG. 8, the detection element unit 10A can be regarded as two capacitors that store electric charge between the pair of electrode plates 40L and 40M and between the pair of electrode plates 40S and 40M, respectively. As in the first embodiment, the presence / absence of the liquid, that is, the liquid surface height is detected based on the detection signals corresponding to the pair of electrode plates 40S and 4M (first electrode pair) having a large facing distance. Further, the ratio of impurities mixed in the liquid is detected by detection signals corresponding to the pair of electrode plates 40M and 40L (second electrode pair) having a narrow facing interval. In the second embodiment, the electrode plate 40M is connected to a ground terminal (frame ground) indicated by “GND”, and the electrode plates 40L and 40S are connected to a signal terminal indicated by “+”.

  As described above, also in the second embodiment, the pair of electrode plates 40S and 40M having a large opposing interval is used for detecting the presence or absence of the liquid. Therefore, when the liquid runs out, the pair of electrode plates 40S and 40S The liquid reliably disappears from between 40M, and the liquid reliably disappears from between the electrode plate 40S and the other surface 21b, and the absence of liquid can be reliably detected. In addition, since the pair of electrode plates 40M and 40L having a narrow facing distance are used to detect the ratio of impurities (relative dielectric constant of oil), the capacitance can be detected with high accuracy.

  In the second embodiment, since the electrode plate 40S connected to the signal terminal (+) is disposed on the base main body 21 side, there is a possibility of being affected by floating charges in the base main body 21 and the like. However, even if it is affected by floating charges, the electrode plate 40S is used for detecting the presence or absence of a liquid, and it is not necessary to detect the capacitance with high accuracy and there is no problem.

  In the above-described embodiment, each electrode plate 40 is formed in a disk shape. However, the present invention is not limited to this, and the electrode plate 40 is arbitrary in shape, size, and the like. However, from the viewpoint of suppressing variation in height at which the liquid contacts the plurality of electrode plates 40, that is, suppressing variation in detection accuracy, the electrode plate 40 is formed in a disc shape, a regular triangle plate shape, a square plate shape, or a regular hexagon shape. It is preferably formed in a regular polygonal plate shape such as a square plate shape or a regular octagonal plate shape.

  In the above-described embodiment, the mounting surface 23a of the flange 23 of the base 20 is welded in a state of being in contact with the outer surface of the side wall portion 503 of the compressor 101. However, the present invention is not limited to this. . For example, a configuration in which the flange 23 is omitted and the peripheral portion of the other surface 21b of the base main body portion 21 of the base 20 is welded while being in contact with the outer surface of the side wall portion of the compressor 101 over the entire circumference, or the side wall portion The base 20 is fixed to the side wall portion 503 so as to close the through hole 503a of the side wall portion 503 unless the object of the present invention, such as fixing the screw 503 and the base 20 with a screw structure and sealing with a flare seal structure. As long as the structure is attached, the attachment structure is arbitrary.

  In the above-described embodiment, the conductive terminal 30 is arranged horizontally and the electrode plate 40 is attached so as to be perpendicular to the conductive terminal 30 along the vertical direction. However, the present invention is not limited to this. is not. For example, even when attached to a side wall portion that is not parallel to the vertical direction, the shape of the conductive terminal 30 and the angle formed by the conductive terminal 30 and the electrode plate 40 are appropriately set so that the plurality of electrode plates 40 are along the vertical direction. A set configuration may be used.

  Moreover, in embodiment mentioned above, although the detection element part 10 and the detection control part 50 were separate bodies, and these were comprised so that fitting was possible as a pair of connector, it is not limited to this, Detection The liquid detection unit which comprised the element part 10 and the detection control part 50 integrally may be sufficient. In this configuration, the liquid detection unit corresponds to a liquid detector.

  FIG. 9 is a front view of a detection element unit as a liquid detector according to the third embodiment of the present invention. 10 is a cross-sectional view taken along line XX in FIG. FIG. 11 is a plan view of the detection element portion of FIG. The detection element unit 10B includes a base 120, a plurality of conductive terminals 130, and three electrode plates 140.

  The base 120 is made of, for example, a metal such as stainless steel, and has a rotationally symmetric shape with the axis L as the central axis. And it has integrally the base main-body part 121 and the cylindrical part 122 which encloses the cavity part 123, and also has the hermetic glass 124 which fixes the four conductive terminals 130. FIG.

  The base main body 121 is formed in a disc shape, and the cylindrical portion 122 is provided to protrude from the outer peripheral edge of the base main body 121 so as to be coaxial with the base main body 121. The base body 121 is formed with four through holes 121c penetrating the outer surface 121a and the other surface 121b serving as the bottom surface of the cavity 123, and a hermetic glass 124 is formed in the through hole 121c. It is fixed. An attachment surface 122a facing the same direction as the other surface 121b of the base main body 121 in the cylindrical portion 122 is an annular flat surface, and is attached to the casing 502 of the compressor 101 in the same manner as in the above embodiment. The through hole 503a provided in the side wall portion 503 of the body 502 is surrounded so as to be in close contact with the outer surface of the side wall portion 503. In the case of the third embodiment, the diameter of the through hole 503a can be reduced.

  The four conductive terminals 130 are made of, for example, a conductive metal such as a nickel alloy, and are each formed in a rod shape that extends straight. Each of the four conductive terminals 130 is inserted into the corresponding through hole 121c, and is fixedly attached to the base main body 121 in a state of being electrically insulated from the base main body 121 by the hermetic glass 124. . In order to fix the conductive terminal 130 to the base main body 121, another insulating material may be used instead of the hermetic glass 124.

  Each of the four conductive terminals 130 is arranged such that a part 131 projects perpendicularly from the other surface 121 b of the base body 121 and the other part 132 projects perpendicularly from the one surface 121 a of the base body 121. Are arranged. The other part 132 of each conductive terminal 130 is brought into contact with the female terminal of the detection control unit as a male terminal when fitted with a detection control unit (not shown).

  The four conductive terminals 130 have the same length. In FIGS. 9 and 10, the lower conductive terminal 130 (indicated by reference numeral 130A in the figure) and the upper conductive terminal 130 (indicated by reference numeral 130B in the figure) Are one by one and are arranged on the upper and lower axes. In FIG. 9 and FIG. 10, there are two conductive terminals 130 (indicated by reference numeral 130C) between the conductive terminals 130A and 130B, and are arranged closer to the conductive terminal 130A side at the target position with respect to the upper and lower axes. Has been.

  The three electrode plates 140 are made of, for example, a conductive metal such as stainless steel, and are formed in the same strip shape. Of the three electrode plates 140, the lower electrode plate 140A is fixedly attached to a part 131 of the conductive terminal 130A, and the upper electrode plate 140B is fixed to a part 131 of the conductive terminal 130B. It is attached. The inner electrode plate 140C is fixedly attached to a part 131 of each of the two conductive terminals 130C. The electrode plates 140A and 140B are respectively fixed to the conductive terminals 130A and 130B on the central axis in the longitudinal direction, and the electrode plate 140C is fixed to the conductive terminals 130C at both edges in the longitudinal direction. The electrode plate 140C has a slightly larger width than the electrode plates 140A and 140B. Each electrode plate 140 is attached to each conductive terminal 130 by, for example, welding or brazing.

  With the above configuration, the electrode plates 140A, 140B, and 140C are arranged in parallel with a space therebetween. Further, the facing distance (first distance) between the pair of electrode plates 140A and 140C is wide, and the facing distance (second distance) between the pair of electrode plates 140B and 140C is narrow. That is, the electrode plate 140C is a common electrode, and the pair of electrode plates 140A and 140C having a first interval as the opposing interval constitutes a “first electrode pair”, and the opposing interval is narrower than the first interval. The pair of electrode plates 140B and 140C having the second interval constitutes a “second electrode pair”.

  In the same manner as in the above-described embodiment, the presence / absence of the liquid, that is, the liquid surface height is detected based on the detection signals corresponding to the pair of electrode plates 140A and 140C (first electrode pair) having a large facing distance. Further, the ratio of the impurities mixed in the liquid is detected by the detection signals corresponding to the pair of electrode plates 140B and 140C (second electrode pair) having a narrow facing distance.

  In the detection element unit 10B of this embodiment, the electrode plates 140A, 140B, and 140C are in the shape of a strip plate, and are arranged in parallel with the axis L of the base 120 and the axis of the conductive terminal 130. Therefore, when attaching to the casing 502 of the compressor 101, by setting the angle around the axis L, the electrode plates 140A, 140B, 140C can be arranged horizontally or arranged parallel to each other along the vertical direction. You can also. In particular, by arranging along the vertical direction, the lubricating oil breakage at the electrode pair is improved. In addition, since the electrode plates 140A, 140B, and 140C have a band plate shape, a necessary area can be secured depending on the length of the electrode plates 140A, 140B, and 140C, so that the width can be reduced and the through hole of the compressor can be secured. The diameter of 503a can be reduced.

(Embodiment of compressor)
Below, the compressor which concerns on one Embodiment of this invention is demonstrated with reference to FIG. FIG. 12 is a cross-sectional view of a compressor according to an embodiment of the present invention. This compressor is provided in a refrigerant circuit of an air conditioner, for example, and is used for circulation of the refrigerant in the refrigerant circuit.

  The compressor 101 employs a rotary system, and is housed in a casing 502 with a motor unit 510 having a motor stator 511 and a motor rotor 512, and a cylinder 521 and a working chamber 522 formed in the cylinder 521. And a compression portion 520 having an annular piston 525. The motor rotor 512 and the annular piston 525 are connected by a crankshaft 530. Further, a lubricating oil K for lubricating the compression unit 520 and the like is accommodated in the housing 502.

  When the crankshaft 530 is rotated by the motor unit 510, the compressor 101 is rotated while the annular piston 525 is in contact with a peripheral wall surface of the working chamber 522. In accordance with the rotation of the annular piston 525, the refrigerant is introduced into the working chamber 522 from the suction pipe 541 through the suction muffler 542 and the introduction pipe 543. Then, the refrigerant is compressed by the annular piston 525 in the working chamber 522, and is led out of the compressor 101 through the discharge muffler 544, the casing 502, and the discharge pipe 545.

  The compressor 101 has the liquid detection unit 1 described above. The detection element portion 10 of the liquid detection unit 1 is attached to a side wall portion 503 along the vertical direction in the housing 502. Specifically, in the detection element unit 10, a part 31 of the plurality of conductive terminals 30 and the pair of electrode plates 40 are inserted into the through holes 503 a provided in the side wall part 503, and the flange part 23 of the base 20 The flange portion 23 is fixed by welding in a state where the entire mounting surface 23a is in contact with the outer surface of the side wall portion 503 around the through hole 503a.

  The four electrode plates 40 of the detection element unit 10 are arranged in parallel to each other along the vertical direction in the housing 502. In the normal state where the lubricating oil K is in an appropriate amount, the detection element unit 10 is one of the four electrode plates 40 in the abnormal state where the entire four electrode plates 40 are submerged below the liquid level and the lubricating oil K is insufficient. It arrange | positions so that a part or the whole may be exposed on a liquid level.

  As mentioned above, according to this embodiment, since it has the liquid detection unit 1 mentioned above, while being able to reduce the attachment space of the detection element part 10, it can suppress the failure by breakage, therefore, it is small and has few failures. can do.

  In the above-described embodiment, the rotary system is used. However, the present invention is not limited to this. For example, a structure using another system such as a scroll system may be used.

(Embodiment of air conditioner)
Below, the air conditioner which concerns on one Embodiment of this invention is demonstrated with reference to FIG. FIG. 13 is a diagram illustrating a schematic configuration of an air conditioner according to an embodiment of the present invention. This air conditioner is used, for example, as an air conditioner provided in a house or a commercial facility.

  The air conditioner 201 includes a refrigerant circuit 210 including an indoor heat exchanger 211, an outdoor heat exchanger 212, an expansion valve 213, the compressor 101 described above, and a flow path switching valve 215.

  The flow path of the refrigeration cycle of the air conditioner 201 is switched to two flow paths of “cooling mode” and “heating mode” by the flow path switching valve 215. In the cooling mode, as indicated by solid arrows in FIG. 13, the refrigerant compressed by the compressor 101 flows into the outdoor heat exchanger 212 from the flow path switching valve 215 and into the expansion valve 213. Then, the refrigerant is expanded by the expansion valve 213 and flows into the indoor heat exchanger 211. The refrigerant that has flowed into the indoor heat exchanger 211 flows into the compressor 101 via the flow path switching valve 215. On the other hand, in the heating mode, the refrigerant compressed by the compressor 101 flows into the indoor heat exchanger 211 from the flow path switching valve 215 and flows into the expansion valve 213 as indicated by the dashed arrows in FIG. Then, the refrigerant is expanded by the expansion valve 213 and circulated in the order of the outdoor heat exchanger 212, the flow path switching valve 215, and the compressor 101.

  In the cooling mode, the outdoor heat exchanger 212 functions as a condenser, the indoor heat exchanger 211 functions as an evaporator, and indoor cooling is performed. In the heating mode, the outdoor heat exchanger 212 functions as an evaporator, the indoor heat exchanger 211 functions as a condenser, and the room is heated.

  As described above, according to the present embodiment, since the compressor 101 having the liquid detection unit 1 described above is provided, the air conditioner 201 with a small size and few failures can be obtained.

  In the above embodiment, an example having only two electrode pairs of the first electrode pair and the second electrode pair has been described. However, the first electrode pair and the second electrode pair may be provided. For example, a plurality of electrode pairs having three or more pairs may be provided.

  In the above embodiment, the conductive terminals 30 and 130 are rod-shaped. However, the present invention is not limited to this, and the conductive terminals may be formed in one piece with the electrode plates 40 and 140 or formed as separate bodies. Good.

  In the above embodiment, the example in which the liquid detection unit is attached to the side wall portion of the compressor has been described. However, the liquid detection unit may be attached to the bottom portion of the casing or other places.

  In addition, embodiment mentioned above only showed the typical form of this invention, and this invention is not limited to embodiment. That is, those skilled in the art can implement various modifications in accordance with conventionally known knowledge without departing from the scope of the present invention. Of course, such modifications are included in the scope of the present invention as long as the liquid detector, the compressor and the air conditioner of the present invention are provided.

1 Liquid detection unit 10, 10A Detection element part (liquid detector)
20 Base 23a Mounting surface 24 Hermetic glass 30 Conductive terminal 31 Part of conductive terminal 32 Other part of conductive terminal 40 Electrode plate 50 Detection controller 120 Base 124 Hermetic glass 130 Conductive terminal 131 Part of conductive terminal 132 Conductive terminal 132 Other part 140 Electrode plate 101 Compressor 502 Housing 503 Side wall (wall)
503a Through hole 201 Air conditioner 210 Refrigerant circuit 211 Indoor heat exchanger 212 Outdoor heat exchanger 213 Expansion valve 215 Flow path switching valve K Lubricating oil

Claims (5)

A liquid detector that detects liquid by capacitance between a plurality of electrode plates,
The plurality of electrode plates include at least a first electrode pair composed of a pair of electrode plates having an opposing interval as a first interval, and a pair of electrodes having an opposing interval as a second interval that is narrower than the first interval. A liquid detector comprising a second electrode pair made of a plate. The liquid detector according to claim 1, which is used for detecting a liquid contained in a housing.
A base attached to the wall so as to close a through hole provided in the wall of the housing;
A plurality of conductive terminals attached so as to protrude from one surface of the base so that at least a part thereof is disposed in the housing;
The plurality of electrode plates are respectively attached to the portions of the corresponding conductive terminals among the plurality of conductive terminals so as to be arranged parallel to each other along the base. The liquid detector according to 1.   3. The liquid detector according to claim 1, wherein each of the plurality of electrode plates is formed in a disc shape or a regular polygon plate shape. A compressor having a casing, a compression section provided in the casing, and a liquid detection section for detecting the lubricant contained in the casing;
The said liquid detection part is comprised including the liquid detector as described in any one of Claims 1-3, The compressor characterized by the above-mentioned.   It is an air conditioner provided with the refrigerant circuit containing an indoor heat exchanger, an outdoor heat exchanger, an expansion valve, and a compressor, Comprising: The said compressor is comprised with the compressor of Claim 4. Air conditioner.

Images