JP2005344612A - Hermetic compressor and refrigerating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem in a conventional device for detecting an oil level by measuring the temperature of an oil in a compressor wherein it is difficult to discriminate an accurate oil level when a plurality of temperature sensors indicate the same temperature. <P>SOLUTION: When the position of the oil level in a casing 10 is discriminated by the detected temperatures of the first temperature sensor 20a and the second temperature sensor 20b, the second temperature sensor 20b is disposed at the bottom face of the casing. Since the second temperature sensor 20b always detects the temperature of a lubricating oil, the detected temperature of the first temperature sensor 20a becomes higher than the detected temperature of the second temperature sensor 20b when the first temperature sensor 20a is put in the lubricating oil, and the oil level is found to be positioned below the first temperature sensor 20a. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hermetic compressor that compresses refrigerant and a refrigeration apparatus including the same.

  2. Description of the Related Art Conventionally, a hermetic compressor formed by sealing a compression mechanism and an electric motor in a casing having a welded structure is known. This hermetic compressor has high reliability because refrigerant does not leak and there is no risk of moisture intrusion, and is widely used in air conditioners and refrigerators (see, for example, Patent Document 1).

  In the hermetic compressor, it is necessary to supply electric power to the electric motor in the casing. For this reason, what is called a sealing terminal excellent in pressure resistance and airtightness is welded to the casing, and electric power is supplied to the electric motor via this sealing terminal.

  Further, in the above-described hermetic compressor, lubricating oil stored in the casing is supplied to a compression mechanism, a bearing, and the like for lubrication. However, the lubricating oil in the casing is discharged from the compressor together with the compressed gas refrigerant. Normally, the lubricating oil circulates through the refrigerant circuit and returns to the compressor, so that the amount of lubricating oil stored in the casing is ensured.

However, depending on the operating conditions, the amount of lubricating oil stored varies, and there is a risk that the amount of lubricating oil stored will be insufficient, leading to poor lubrication.
In order to solve the above-mentioned problems, a proposal has been made to protect the compressor by detecting the position of the oil level in the casing with a temperature sensor and detecting an insufficient amount of lubricating oil stored. In other words, when a decrease in the oil level is detected, the compressor is stopped, or a protective operation such as an operation of collecting the refrigeration oil from the refrigerant circuit is performed to avoid damage to the compressor (for example, patents). Reference 2).

  However, in this case, when there is no temperature difference between the two measurement points, there is a problem that it cannot be determined whether the detected temperature is the temperature of the lubricating oil or the temperature of the refrigerant gas. That is, it was not possible to determine whether the lubricating oil was sufficient or insufficient.

In order to solve the above problem, a proposal has been made to provide a temperature detection means at a position where the temperature of the refrigerant gas can always be detected (see, for example, Patent Document 3).
JP-A-6-159274 JP 2001-12351 A JP 2001-32772 A

  As described above, in the air conditioner, it has been proposed to detect the oil level of the lubricating oil in order to control the lubricating oil of the compressor.

  In this method of detecting the oil level, the oil level is detected based on the temperature difference between the measurement points in the casing of the compressor.

  However, since the oil temperature detection unit is exposed and installed in the casing in the conventional configuration, the splash of lubricating oil is generated even though the actual oil level exists below the oil temperature detection unit. It took the oil temperature detector and had the problem of misjudging the oil level.

  The present invention solves the above-described conventional problems, and reliably detects the position of the oil level in the casing while maintaining a simple configuration of the compressor, and at the same time, the reliability of the refrigeration apparatus using the compressor. The purpose is to provide improved sex.

  In order to solve the above-described conventional problems, the compressor of the present invention includes an oil temperature detecting means disposed at a position corresponding to the lower limit of the lubricating oil surface in the casing to detect the temperature of the lubricating oil, and a casing bottom. An oil temperature detecting means is provided.

  Thus, when the detected temperature of the oil temperature detecting means arranged at the position corresponding to the lower limit of the lubricating oil level matches the detected temperature of the oil temperature detecting means arranged at the bottom of the casing, the oil level becomes the lubricating oil level. It can be determined that the oil temperature is present above the oil temperature detecting means disposed at the position corresponding to the lower limit of the above.

  In the compressor of the present invention, the oil temperature detecting means arranged at the bottom of the casing is provided at a position where the lubricating oil always exists.

  Thereby, when there is no temperature difference between the detected temperatures of the two temperature detecting means, it is possible to avoid the problem that it cannot be determined whether the detected temperature is the temperature of the lubricating oil or the temperature of the refrigerant gas.

  Since the compressor of the present invention always detects the temperature of the lubricating oil, the compressor according to the present invention is based on the temperature difference between the temperature sensor arranged at the position corresponding to the lower limit of the lubricating oil surface and the temperature sensor arranged at the bottom of the casing. The lubricating oil level can be accurately determined.

  According to a first aspect of the present invention, in the compressor in which the lubricating oil is stored in the casing and the refrigerant gas is sucked in, compressed and discharged, the detecting means is provided when the means for detecting the temperature is provided in the casing. By providing it at a position corresponding to the lower limit of the oil level inside, when the oil level is sufficiently secured and does not fall below the lower limit, the temperatures detected by the two detection means can be made equal.

  In the second invention, in particular, when one of the temperature detecting means provided in the compressor of the first invention is provided at a position where the lubricating oil always exists, there is no temperature difference between the detected temperatures of the two temperature detecting means. The problem that it cannot be determined whether the detected temperature is the temperature of the lubricating oil or the temperature of the refrigerant gas can be avoided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a sectional view of a compressor in the first embodiment of the present invention.

  In FIG. 1, the compressor is formed by housing a compressor section 11 and an electric motor section 12 in a cylindrical container-like casing 10, and is configured in a so-called high-pressure dome shape. At the upper end of the casing 10, a discharge pipe 14 which is a refrigerant pipe for sending out a compressed refrigerant gas is provided.

The compressor unit 11 is configured as a so-called rolling piston type and is fixed to the casing 10. A suction pipe 13, which is a refrigerant pipe for sucking refrigerant gas, is connected to the compressor section 11 via an accumulator 16. The compressor unit 11 is connected to the electric motor unit 12 by a drive shaft 15 and is rotationally driven by the electric motor unit 12.

  Although not shown, the drive shaft 15 includes a centrifugal pump and an oil supply path, and is provided through the compressor unit 11. The centrifugal pump is provided at the lower end portion of the drive shaft 15 and is configured to pump up the lubricating oil stored in the bottom portion of the casing 10 as the drive shaft 15 rotates. On the other hand, the oil supply path is formed inside the drive shaft 15 along the axial direction thereof, and is configured to supply the lubricating oil pumped up by the centrifugal pump to each sliding portion.

  The casing 10 of the compressor is provided with a first temperature sensor 20a and a second temperature sensor 20b which are oil temperature detecting means. The first temperature sensor 20a and the second temperature sensor 20b detect the temperature of the lubricating oil.

  The first temperature sensor 20 a is provided at a position below the casing 10 and corresponding to the lower limit of the oil level position in the casing 10. The second temperature sensor 20 b is provided at the bottom of the casing 10.

  The first temperature sensor 20 a and the second temperature sensor 20 b are attached to the sealed terminal 21.

  The sealing terminal 21 includes a disk-like base 22 attached to the casing 10 by welding, and three electrode pins 23 that pass through the base 22. Each electrode pin 23 is fixed to the base 22 via a glass insulator 24 and is insulated from the base 22.

  A first temperature sensor 20a and a second temperature sensor 20b are connected to one end of each electrode pin 23, and a signal line is connected to the other end. The other end of each electrode pin 23 is connected to the controller 30.

  About the compressor comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, during operation, lubricating oil is discharged from the compressor together with the discharged refrigerant. Therefore, the position of the oil level 17 in the casing 10 varies during operation. In the compressor of this embodiment, the oil level position in the casing 10 is detected by the first temperature sensor 20a and the second temperature sensor 20b. Here, in the case of the high-pressure dome type, during operation, the lubricating oil is about 60 ° C., whereas the refrigerant gas is about 80 ° C., and there is a clear difference between the temperatures of the two. In addition, said temperature value is an illustration and it changes with driving | running states etc. The temperature sensor 20 detects the position of the oil surface 17 based on the difference between the temperature of the lubricating oil and the temperature of the refrigerant gas.

  Specifically, in a state where the oil level 17 exists above the first temperature sensor 20a, the detected temperature of the first temperature sensor 20a becomes the temperature of the lubricating oil, and coincides with the detected temperature of the second temperature sensor 20b. Further, in the state where the oil level 17 exists below the first temperature sensor 20a, the first temperature sensor 20a exists in the refrigerant gas atmosphere, and therefore the detected temperature of the first temperature sensor 20a is detected by the second temperature sensor 20b. It becomes higher than the temperature.

  Therefore, when the detected temperature of the first temperature sensor 20a matches the detected temperature of the second oil temperature sensor 20b, the oil level 17 exists above the first temperature sensor 20a and is higher than the detected temperature of the first temperature sensor 20a. When the detected temperature of the two temperature sensor 20b is high, it is determined that the oil level 17 exists below the first temperature sensor 20a.

  As described above, in the present embodiment, by disposing the second temperature sensor 20b at the bottom of the casing 10, the position of the oil level can be determined even when the detected temperatures of the two temperature sensors are the same.

  Further, the position where the first temperature sensor 20a is disposed is not limited to the lower limit position of the oil level 17, and may be installed at the upper limit position. This makes it possible to detect an excessive state of lubricating oil in the casing 10.

  Further, the first temperature sensor 20a is not limited to one, and a plurality of first temperature sensors 20a may be arranged. As a result, the position of the oil surface 17 of the lubricating oil can be determined in more detail.

  In addition, the present invention may be applied only to a refrigeration machine, a heating machine, or a compressor other than a refrigeration apparatus.

  As described above, the compressor according to the present invention accurately determines the position of the oil level in the compressor casing based on the temperatures detected by the two temperature sensors, and prevents damage to the compressor due to lack of lubricating oil. Therefore, it can be applied to uses such as control of a compressor used in a refrigeration cycle.

Sectional drawing of the compressor in embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Casing 11 Compressor part 12 Electric motor part 13 Drive shaft 14 Lubricating oil surface 20a Temperature sensor 20b Temperature sensor 21 Sealing terminal 22 Base 23 Electrode pin 24 Insulator 30 Controller

Claims (3)

In the compressor in which the lubricating oil is stored in the casing and the refrigerant gas is sucked in, compressed, and discharged, an oil level detecting device having a structure in which one of the plurality of temperature sensors is arranged on the bottom surface of the casing is provided. Hermetic compressor. The hermetic compressor according to claim 1, wherein the temperature sensor is installed at a position corresponding to a lower limit of the oil level inside the casing. A refrigerating apparatus comprising the compressor according to claim 1, further comprising a determination unit that determines a lubricating oil level from temperatures detected by a plurality of temperature sensors.