JPH0799154B2 - Hermetic compressor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hermetic compressor having an oil level detection device for detecting the oil level height of lubricating oil stored at the bottom of a compressor.

(Prior Art) Generally, when the compressor is stopped, a large amount of refrigerant may flow into the compressor and dissolve in the lubricating oil stored in the compressor. For this reason, when the compressor is restarted, the oil level rises and the lubricating oil flows out of the machine from the discharge pipe, the lubricating oil is reduced below the refuelable amount, and metal burn of the drive equipment occurs. The problem occurs.

Therefore, it is necessary to prevent the lubricating oil from rising by providing the compressor with a detection device for detecting the oil level of the lubricating oil.

As the detection device, a proximity switch type oil level sensor and a photoelectric type oil level sensor are known, but each has its advantages and disadvantages. On the other hand, the applicant of the present invention has proposed an oil level detection position using a float switch that performs an ON operation and an OFF operation depending on the fluctuation of the oil level as shown in FIG. 5 (Japanese Patent Application No. 63-160954). issue).

This float switch comprises a cover body (8) having a conductive inner surface (81) constituting a first switch contact and allowing oil to flow therein, and the conductive inner surface inside the cover body (8). The protrusion-like conductor (9) that is insulated from the (81) and the protruding conductor (9) moves up and down due to the change in the oil surface position flowing into the cover body (8), and the up and down movement causes the movement. A spherical float conductor (10) that short-circuits between the electrically conductive inner surface (81) and the projecting conductor (9). The throat switch is arranged on the inner wall surface of the closed casing (1), Since the spherical flow conductor (10) simultaneously contacts the cover body (8) and the projecting conductor (9) when the oil level of the lubricating oil (0) becomes lower than the refillable position, The float switch is turned on and the amount of lubricating oil is less than the required amount. It is designed to detect that something is wrong.

(Problems to be Solved by the Invention) However, in an oil level detection device using a float switch, detection is made when the amount of lubricating oil becomes less than necessary due to movement of the float conductor (10). So
Accurate detection is not possible, and each of the above-mentioned oil level detection devices only detects when the oil level of the lubricating oil in the compressor reaches a height equal to or lower than the refillable position,
Only the lack of lubricating oil can be detected.Therefore, an incorrect state before the lack of lubricating oil, that is, when the compressor is stopped, a large amount of refrigerant flows into the compressor and dissolves in the lubricating oil, and It is not possible to detect a state where the oil level rises abnormally when activated.

Moreover, in the float switch, the power supply line (91) connected to the cover body (8) and the projecting conductor (9) must be wired in the compressor under high pressure and high temperature. There was a problem with material selection and safety.

The present invention has been developed in view of the above circumstances, and an object thereof is to provide a primary space (5) in a closed casing (1).
(EN) Provided is a hermetic compressor capable of accurately detecting an abnormal rise in the oil level of lubricating oil, and preventing the outflow of lubricating oil from the compressor and the seizure of the drive equipment of the compressor.

(Means for Solving the Problem) The present invention, however, is provided with the outer peripheral surface of the closed casing (1),
An ultrasonic sensor (7) for transmitting an ultrasonic wave and receiving a reflected wave is brought into contact with a height position corresponding to an abnormal oil level rising height [H] in the primary space (5) in the casing (1). Along with this, when the ultrasonic sensor (7) detects an abnormal rise in the oil level in the primary space (5), suction closing means (71) is provided to prevent the inflow of suction fluid to be sucked into the compression element (3). It is characterized by that.

Further, it is preferable that the reflecting surface (33b) for reflecting the ultrasonic wave transmitted from the ultrasonic sensor (7) is provided on the upper bearing boss portion (33a) of the drive shaft (4) of the compression element (3). is there.

(Operation) According to the present invention, since the propagation speeds of ultrasonic waves in liquid and gas are significantly different, the closed casing (1)
The ultrasonic sensor (7) in contact with the outer peripheral surface of the internal space (5) in the closed casing (1) is different due to the difference in the time required from transmitting the ultrasonic wave to receiving the reflected wave. The abnormal rise of the oil level can be accurately detected, and when the abnormal rise of the oil level is detected, the suction port (38) of the compressor is closed and the suction element sucked into the compression element (3). Since the inflow of the fluid is prevented, the oil level can be suppressed from further increasing, and the oil level can be lowered for a long time to prevent the lubricating oil from flowing out of the compressor.

Furthermore, since the ultrasonic sensor (7) can be fixed in contact with the outside of the compressor, the wiring of the power supply line can be performed only outside the compressor.

Further, the reflection surface (33b) for reflecting the ultrasonic wave transmitted from the ultrasonic sensor (7) is provided on the upper bearing boss portion (33a) of the drive shaft (4) in the compression element (3), so that it is redundant. It can be easily provided without arranging various members.

FIG. 1 shows a rotary compressor as an example of a hermetic compressor to which the oil level detection device according to the present invention is applied. A motor (2) and a compression element ( 3) is incorporated, an oil sump (1a) is provided at the bottom, and a discharge pipe (12) is connected to the top.

The motor (2) arranged in the upper part of the inside of the closed casing (1) includes a stator (21) and a rotor (22), and a drive shaft (4) is provided at a lower position of the motor (2).
A compression element (3) interlockingly connected via. The primary space (5) is provided below the motor (2).
The secondary space (6) is formed on the upper part.

The compression element (3) includes a cylinder (32) having a cylinder chamber (31) and a suction port (38) forming a refrigerant flow port for introducing a suction refrigerant into the cylinder chamber (31); Front head (33) fixed to the upper and lower parts of the cylinder (32)
Also, the rear head (34), the muffler (35) (36) covering the entire outer side thereof, and the eccentric shaft portion (4a) of the drive shaft (4) are fitted to rotate in the cylinder chamber (31). Comprised of freely installed rollers (37), said inlet (38)
The suction pipe (11) is connected to. The refrigerant supplied from the suction port (38) to the cylinder chamber (31) of the cylinder (32) is supplied to the roller (3) by the drive shaft (4).
It is compressed by rotating 7).

Therefore, the present invention makes it possible to detect an abnormal rise in the oil level of the lubricating oil in the primary space (5), and further, by detecting the abnormal rise, the suction port (38) of the hermetic compressor is closed, The hermetic compressor is controlled, and the oil level detecting device and the control system will be described below.

First, in the oil level detection device shown in FIG. 1, the casing (1) is provided on the outer peripheral surface of the closed casing (1) at a height position corresponding to an abnormal oil level rise height (H) in the primary space (5). The ultrasonic sensor (7) that transmits ultrasonic waves and receives reflected waves is abutted and fixed to the ultrasonic anti-slope (33b) provided at the height (H) position in 1). is there.

More specifically, the ultrasonic sensor (7) is
On the outer peripheral surface of the casing (1), the primary space (5)
In the motor (2), the lower end of the coil end (21a) of the stator (21) and the upper surface of the upper muffler (35) of the compression element (3) are brought into contact with and fixed at a height [H] position. Therefore, by transmitting the ultrasonic wave to the reflecting surface (33b) and receiving the reflected wave, when the oil level of the lubricating oil is higher than the height [H] position, that is, the ultrasonic wave is When it travels in liquid, the oil level is at the height [H]
The oil level can be detected by the difference in the time required from the transmission to the reception of the ultrasonic wave when the ultrasonic wave is lower than the position, that is, when the ultrasonic wave propagates in the gas.

The reflecting surface (33b) is, as shown in FIG. 2 to FIG. 3, one side of the outer peripheral surface of the bearing boss portion (33a) of the front head (33) of the compression element (2), from above. It is formed by providing an arcuate dent extending to the bottom.

Further, FIG. 4 shows the ultrasonic sensor (7) as described above.
It shows a control system of the hermetic compressor (70) in which the transmission is transmitted to the output unit of the transmission / reception unit (72) of the sensor (7) that transmits ultrasonic waves and receives the reflected waves. Height detection unit (73) that detects the height from the time required until reception
And a comparison unit (74) for comparing the oil level height [H] set by the setting unit (75) with the actually measured oil level height detected by the height detection unit (73).

On the other hand, the suction port (38) of the compressor (70) or the suction pipe (11) connected to the suction port (38) has a suction port (38) as shown in FIGS. The on-off valve (76) for closing the valve 38) is interposed, and the measured oil level height detected by the height detector (73) is on the output side of the comparator (74). When the oil level height [H] set in (75) is reached, output is made to close the on-off valve (76),
The suction closing means (71) for closing the suction port (38) is connected.

However, when the compressor is stopped, a large amount of refrigerant
When the oil flows into the compressor and dissolves in the lubricating oil, the oil level rises when the compressor is restarted. At this time, ultrasonic waves are emitted from the ultrasonic sensor (7) to the anti-slope (33b).
The oil level height measured by the height detection unit (73) is detected from the time required from the transmission to the reception, and the oil level height is detected by the setting device (75). When the set oil level height [H] is reached, the suction closing means (71) is actuated by the output of the comparing part (74) and the on-off valve (76) is closed. As a result, the suction port (38)
Is closed, and moreover, since the compressor operates while the suction port (38) is closed, no refrigerant is discharged from the compression element (3), and therefore,
The refrigerant is not discharged to the outside of the compressor either.

That is, the refrigerant dissolved in the lubricating oil is discharged together with the refrigerant,
The mist-like lubricating oil is not discharged outside the compressor, and as a result, the lubricating oil can be prevented from flowing out of the compressor.

Moreover, since the temperature inside the closed casing (1) can be raised by the heat generated by driving the motor (2), the refrigerant dissolved in the lubricating oil is vaporized and the abnormal oil level rise height [H ] While the oil level rise above can be suppressed, the oil level can be lowered to the steady oil level in a short time. Thus, the lubricating oil can be prevented from flowing out of the compressor, so that the problem of oil shortage can be solved without abnormal lowering of the oil level.

(Effect of the invention) According to the present invention, on the outer peripheral surface of the closed casing (1), at a height position corresponding to the abnormal oil level rise height [H] in the primary space (5) in the casing (1). , An ultrasonic sensor (7) for transmitting an ultrasonic wave and receiving a reflected wave is brought into contact, and when an abnormal oil level rise in the primary space (5) is detected by the ultrasonic sensor (7), a compression element ( Since the hermetic compressor is provided with the suction closing means (71) for preventing the inflow of the suction fluid to be sucked into 3), a large amount of refrigerant flows into the compressor and dissolves in the lubricating oil when the compressor is stopped. In this case, the oil level rises abnormally when the compressor is restarted, but this abnormal oil level rise can be detected accurately and safely with a simple structure, and the oil level rises. Is abnormally increased, the suction closing means (71 As a result, the warm-up operation is performed while the suction port (38) is closed, so that the dissolved refrigerant in the lubricating oil can be vaporized and released, and the oil level can be lowered, while the warm-up operation is performed. Since the refrigerant is not discharged from the element (3), the lubricating oil is not discharged out of the compressor due to the discharge of the refrigerant.

Therefore, as described above, the oil surface height can be lowered to the steady oil surface height in a short time, so that oil running out can be reliably prevented and seizure of the bearing portion or the like due to oil running out can be prevented.

Further, the upper bearing boss portion (33a) of the drive shaft (4) of the compression element (3) is provided with a reflection surface (33b) for reflecting the ultrasonic wave transmitted from the ultrasonic sensor (7), thereby compressing Since the constituent parts of the element (3) can be utilized and it is not necessary to dispose an extra member, the number of parts can be reduced accordingly.

[Brief description of drawings]

1 is a sectional view of a compressor to which an embodiment of the hermetic compressor according to the present invention is applied, FIG. 2 is a perspective view of a front head, and FIG. 3 is a plan view of the front head of FIG. FIG. 4 is a block diagram showing a control system of a hermetic compressor according to the present invention, and FIG. 5 is a sectional view of a conventional example. (1) …… Hermetic casing (1a)… Oil sump (2) …… Motor (3) …… Compression element (33a)… Front head bearing boss (33b)… Reflecting surface (4) …… Drive shaft (5) …… Primary space (6) …… Secondary space (7) …… Ultrasonic sensor (71) …… Suction closure means (H) …… Abnormal oil level rise height

Claims (2)

[Claims] 1. A motor (2) at the top of a closed casing (1) having an oil sump (1a) at the bottom and a compression element (3) at the bottom.
And a secondary space located above the motor (2) by releasing discharge gas discharged from the compression element (3) into a primary space (5) located below the motor (2). In the hermetic compressor taken out from (6) to the outside, on the outer peripheral surface of the casing (1), at a height position corresponding to the abnormal oil level rise height [H] in the primary space (5), When the ultrasonic sensor (7) for transmitting the ultrasonic wave and receiving the reflected wave is brought into contact with the ultrasonic sensor (7) and an abnormal oil level rise in the primary space (5) is detected by the ultrasonic sensor (7), the compression element ( A hermetic compressor characterized in that a suction closing means (71) for preventing the inflow of suction fluid to be sucked into 3) is provided. 2. A reflecting surface (33b) for reflecting ultrasonic waves transmitted from said ultrasonic sensor (7) is provided on an upper bearing boss (33a) of a drive shaft (4) of a compression element (3). The hermetic compressor according to Item 1.