JP7657018B2 - Rotary Compressor - Google Patents

Description

The present invention relates to a rotary compressor.

Conventionally, a sealed electric rotary compressor, such as that shown in Patent Document 1, is known that includes a housing, a rotating shaft that extends vertically within the housing and supports a cylinder at its lower part, and a discharge pipe that penetrates the top wall of the housing in the thickness direction, has a lower part located within the housing and an upper part located outside the housing, and discharges the refrigerant compressed within the housing to the outside of the housing.

JP 2015-17574 A

However, conventional rotary compressors are required to be smaller and lighter. When rotary compressors are made smaller and lighter, the space required is reduced, and some of the lubricating oil that is mixed into the refrigerant and circulates with the refrigerant is more likely to be discharged outside the housing through the discharge pipe, improving the oil circulation rate, and there is room for improvement in this regard.

The present invention was made in consideration of the above-mentioned problems, and aims to provide a rotary compressor that can reduce the oil circulation rate by suppressing the release of lubricating oil that accompanies size and weight reduction.

In order to achieve the above object, a rotary compressor according to one aspect of the present invention includes a housing, a rotating shaft having a cylinder supported at a lower portion thereof and extending vertically within the housing, and a discharge pipe that is provided coaxially with the rotating shaft, penetrates a top wall portion of the housing in a thickness direction, and discharges a refrigerant compressed within the housing to an outside of the housing, wherein the rotating shaft includes a first cylindrical member having a constant outer diameter over its entire length, and a shaft taper portion whose diameter decreases from an upper end of the first cylindrical member toward the upper side, and an upper portion of the first cylindrical member is disposed in a direction perpendicular to the outer periphery of the rotating shaft. the discharge pipe protrudes upwardly beyond a rotor fixed to a surface, the discharge pipe comprises a second cylindrical member of the same outer diameter over its entire length and a different diameter portion extending upwardly from the second cylindrical member, only the lower portion of the second cylindrical member of the discharge pipe protrudes downwardly beyond the top wall portion of the housing, the lower end of the second cylindrical member and the upper end of the shaft taper portion are arranged in close proximity to each other in a position directly opposed to each other only through the internal space within the housing, and when the inner diameter of the second cylindrical member is D (mm), the distance L (mm) between the upper end of the shaft taper portion and the lower end of the second cylindrical member satisfies the following formula (1):

According to the rotary compressor of the above aspect, by bringing the rotating shaft close to the discharge pipe and setting the distance L between the upper end of the rotating shaft and the lower end of the discharge pipe within the range of the above formula (1), the lubricating oil can be collided with the rotating shaft near the discharge pipe, and the oil droplet flow rate can be reduced. This makes it possible to prevent the lubricating oil from being discharged to the outside of the housing through the discharge pipe. Note that when the distance L is smaller than D and the discharge pipe and the rotating shaft are close to each other, pressure loss is likely to occur in the compressed refrigerant. Also, when the distance L is larger than 5D and the discharge pipe and the rotating shaft are separated from each other, the amount of lubricating oil discharged increases.
In this way, in the rotary compressor according to the present embodiment, the release of lubricating oil that accompanies the reduction in size and weight can be suppressed, and therefore the oil circulation rate can be reduced. Therefore, even a small and lightweight rotary compressor can be operated without improving the oil circulation rate.

In the above rotary compressor, the second cylindrical member may have an inner diameter D that satisfies the following formula (2).

In this case, by setting the inner diameter D of the discharge pipe within the range of formula (2) above, the lubricating oil can be caused to collide with the rotating shaft near the discharge pipe, and the effect of slowing down the flow rate of the oil droplets can be more effectively achieved. If the inner diameter D of the discharge pipe is smaller than 2 mm, a pressure loss occurs due to the smaller inner diameter of the discharge pipe. Also, if the inner diameter D of the discharge pipe is larger than 15 mm, the area of collision with the rotating shaft when the lubricating oil droplets flow into the discharge pipe with the discharge gas flow is reduced, making it impossible to slow down the flow rate of the lubricating oil droplets, and the oil circulation rate remains the same as that of products currently on the market.

The rotary compressor of the present invention can reduce the oil circulation rate by suppressing the release of lubricating oil that accompanies the reduction in size and weight.

1 is a vertical cross-sectional view showing a configuration of a rotary compressor according to an embodiment of the present invention.

The following describes a rotary compressor according to an embodiment of the present invention with reference to the drawings. This embodiment shows one aspect of the present invention, does not limit the present invention, and can be modified as desired within the scope of the technical concept of the present invention.

As shown in FIG. 1, the rotary compressor according to this embodiment (hereinafter simply referred to as compressor 1) is an example of a hermetically sealed electric rotary compressor used in, for example, air conditioners and refrigeration devices, and includes a compressor body 10, a suction pipe 11, and an accumulator 12.

The compressor body 10 includes a housing 2, a rotating shaft 3, an upper bearing 4A, a lower bearing 4B, an electric motor 5, and a rotary compression section 6. The rotary compression section 6 is provided with a disk-shaped cylinder 60 within the housing 2.
Here, the central axis of the housing 2 and the rotating shaft 3 are arranged on a common axis that extends vertically (up and down), and hereinafter this common axis is referred to as the rotation axis O. The rotating shaft 3 is arranged so that its extension direction is the vertical direction, and is accommodated within the housing 2 so as to be rotatable around the rotation axis O.

The housing 2 is sealed and extends in the vertical direction. The housing 2 has a cylindrical main body 21, and an upper lid 22 (top wall) and a lower lid 23 that close the upper and lower openings of the main body 21. The housing 2 has an opening 24 formed in a position facing the outer circumferential surface of the cylinder 60 at the lower side wall. The cylinder 60 has an intake port 25 formed in a position facing the opening 24, which communicates with a predetermined position within the cylinder 60.

An oil reservoir is formed at the bottom of the housing 2 by storing oil (lubricating oil). When the lubricating oil is initially charged, the liquid level of the oil reservoir is located above the rotary compression section 6. This allows the rotary compression section 6 to operate within the oil reservoir.

The upper lid 22 is provided with a discharge pipe 13 that penetrates in the thickness direction, with the lower part 13A located inside the housing 2 and the upper part 13B located outside the housing 2. The discharge pipe 13 contains lubricating oil and discharges the compressed refrigerant to the outside of the housing 2.

The lower end 13a of the discharge pipe 13 is disposed adjacent to a position facing the upper end 3a of the rotating shaft 3. In this embodiment, the pipe axis of the discharge pipe 13 is disposed coaxially with the rotation axis O (the central axis of the rotating shaft 3), but this is not limited to being coaxial. In other words, the rotating shaft 3 and the discharge pipe 13 may be offset from each other when viewed from the direction of the rotation axis O.

In the compressor 1, when the inner diameter of the discharge pipe 13 is D (mm), the distance L (mm) between the upper end 3a of the rotating shaft 3 and the lower end 13a of the discharge pipe 13 is set to satisfy the following formula (1). When the distance L is smaller than D and the discharge pipe 13 and the rotating shaft 3 are close to each other, pressure loss is likely to occur in the compressed refrigerant. When the distance L is larger than 5D and the discharge pipe 13 and the rotating shaft 3 are far apart, the amount of lubricating oil discharged increases.
It is more preferable that the range of the inner diameter D of the discharge pipe 13 is set to satisfy the following formula (2). In other words, when the inner diameter D of the discharge pipe 13 is smaller than 2 mm, a pressure loss occurs due to the small inner diameter of the discharge pipe. Also, when the inner diameter D of the discharge pipe 13 is larger than 15 mm, the area of collision with the rotating shaft 3 when the lubricating oil droplets flow into the discharge pipe 13 with the discharge gas flow is reduced, and the flow rate of the lubricating oil droplets cannot be decelerated, and the oil circulation rate does not change from that of the current market product.
Further, it is more preferable that the inner diameter D of the discharge pipe 13 is 2.5 mm or more and 13 mm or less (2.5 mm≦D≦13 mm).

An accumulator 12 is provided on the outside of the housing 2 to separate the refrigerant into gas and liquid before supplying it to the compressor body 10. The accumulator 12 is fixed to the outer circumferential surface of the housing 2 via a bracket 14. The accumulator 12 is provided with the above-mentioned suction pipe 11 for sucking the refrigerant inside into the compressor body 10. The suction pipe 11 connected to the accumulator 12 is connected to the suction port 25 through an opening 24 of the housing 2. The accumulator 12 supplies the gas phase of the refrigerant to the rotary compression section 6 through the suction pipe 11.

The electric motor 5 is accommodated in the vertical center of the housing 2. The electric motor 5 has a rotor 51 and a stator 52. The rotor 51 is fixed to the outer circumferential surface of the rotating shaft 3, and is disposed above the rotary compression unit 6. The stator 52 is disposed so as to surround the outer circumferential surface of the rotor 51, and is fixed to the inner surface 21 a of the main body 21 of the housing 2.
A power source (not shown) is connected to the electric motor 5 configured as above. The electric motor 5 is configured to rotate the rotating shaft 3 by electric power from the power source.

The upper bearing 4A and the lower bearing 4B are arranged so as to sandwich the rotary compression unit 6 from above and below. The upper bearing 4A and the lower bearing 4B are each made of a metal material, and are fixed to a cylinder 60 constituting the rotary compression unit 6 with a bolt 61.
The rotating shaft 3 is supported rotatably about a rotation axis O by an upper bearing 4A and a lower bearing 4B.

The rotary compression section 6 is disposed at the bottom of the housing 2 below the electric motor 5. The rotary compression section 6 has a cylinder 60, an eccentric shaft section 62, and a piston rotor 63.

The cylinder 60 has a compression chamber 60A, a suction hole 60B, and a discharge hole (not shown). The compression chamber 60A is formed inside the cylinder 60. The compression chamber 60A accommodates a piston rotor 63.
The cylinder 60 is fixed to the inner surface 21 a of the main body portion 21 of the housing 2 .

The eccentric shaft portion 62 is provided at the lower end of the rotating shaft 3 and is offset in a direction perpendicular to the central axis of the rotating shaft 3 inside the piston rotor 63 .
The piston rotor 63 has a cylindrical shape with an outer diameter smaller than the inner diameter of the cylinder 60, is disposed inside the cylinder 60, and is inserted into and fixed to the eccentric shaft portion 62. The piston rotor 63 rotates eccentrically with respect to the rotation axis O as the rotating shaft 3 rotates.

The suction hole 60B is a hole that allows the refrigerant to flow into the inside of the cylinder 60.
The refrigerant compressed by the rotary compression section 6 is discharged through a discharge hole (not shown) into the internal space of the housing 2, which is kept at an intermediate pressure.

The cylinder 60 is provided with a blade (not shown) that divides the compression chamber 60A into two and is elastically pressed by a compression spring (not shown) so that its tip is always pressed against the outer circumferential surface of the piston rotor 63.

The eccentric shaft portion 62 has an outer diameter that is slightly smaller than the inner diameter of the piston rotor 63. As a result, when the rotating shaft 3 rotates, the eccentric shaft portion 62 revolves around the rotating shaft 3, and the piston rotor 63 rolls eccentrically within the cylinder 60.

In this type of compressor 1, refrigerant is taken into the accumulator 12, the refrigerant is separated into gas and liquid within the accumulator 12, and the gas phase is supplied from the suction pipe 11 through the suction port 25 of the cylinder 60 to the compression chamber 60A, which is the internal space of the cylinder 60.
The eccentric rotation of the piston rotor 63 gradually reduces the volume of the compression chamber 60A, compressing the refrigerant. A discharge hole (not shown) for discharging the refrigerant is formed at a predetermined position of the cylinder 60, and this discharge hole is equipped with a reed valve (not shown). As a result, when the pressure of the compressed refrigerant increases, the reed valve is pushed open and the refrigerant is discharged to the outside of the cylinder 60. The discharged refrigerant is discharged from a discharge pipe 13 provided at the top of the housing 2 to an external piping (not shown).

Next, the operation of the above-mentioned rotary compressor will be specifically described with reference to the drawings.
In the compressor 1 according to this embodiment, as shown in FIG. 1, by bringing the rotating shaft 3 close to the discharge pipe 13 and setting the distance L between the upper end 3a of the rotating shaft 3 and the lower end 13a of the discharge pipe 13 within the range of the above formula (1), the lubricating oil can be made to collide with the rotating shaft 3 near the discharge pipe 13, thereby slowing down the oil droplet flow velocity.
This makes it possible to prevent the lubricating oil from being discharged outside the housing 2 through the discharge pipe 13.

In addition, in this embodiment, by setting the inner diameter D of the discharge pipe 13 within the range of the above formula (2), the lubricating oil can be collided with the rotating shaft 3 near the discharge pipe 13, and the effect of slowing down the oil droplet flow rate can be more effectively achieved.

In this way, the compressor 1 according to this embodiment can suppress the release of lubricating oil that accompanies the reduction in size and weight, and therefore can reduce the oil circulation rate. Therefore, even a small and lightweight rotary compressor 1 can be operated without improving the oil circulation rate.

The above describes an embodiment of the rotary compressor according to the present invention, but the present invention is not limited to the above embodiment and can be modified as appropriate without departing from the spirit of the invention.

For example, in this embodiment, the inner diameter D of the discharge pipe 13 is set to satisfy (2) above, but the inner diameter D of the discharge pipe 13 may be configured by only setting the distance L between the upper end 3a of the rotating shaft 3 and the lower end 13a of the discharge pipe 13 without limiting the numerical range of the inner diameter D of the discharge pipe 13.

In addition, in this embodiment, the upper lid 22 is the top wall portion of the housing 2 through which the discharge pipe 13 passes, but the discharge pipe 13 may be provided on the top wall portion of a housing in which the main body 21 and the upper lid 22 are integrated.

The shape, size, and other configurations of the housing 2, rotating shaft 3, upper bearing 4A, lower bearing 4B, electric motor 5, rotary compression section 6 (cylinder 60, eccentric shaft section 62, piston rotor 63), and accumulator 12 can be set as appropriate.

In addition, the components in the above-described embodiments may be replaced with well-known components as appropriate without departing from the spirit of the present invention, and the above-described embodiments may be combined as appropriate.

1. Compressor (rotary compressor)
Reference Signs List 2 Housing 3 Rotating shaft 3a Upper end 4A Upper bearing 4B Lower bearing 5 Electric motor 6 Rotary compression section 10 Compressor body 12 Accumulator 13 Discharge pipe 13a Lower end 21 Body section 22 Upper lid section (top wall section)
23 Lower cover 60 Cylinder O Rotation axis

Claims (2)

Housing and
a rotating shaft having a cylinder supported at its lower portion and extending vertically within the housing;
a discharge pipe that is provided coaxially with the rotating shaft, that penetrates a top wall portion of the housing in a thickness direction, and that discharges the refrigerant compressed in the housing to an outside of the housing;
Equipped with
The rotating shaft includes a first cylindrical member having a constant outer diameter over its entire length, and a shaft taper portion whose diameter decreases from an upper end of the first cylindrical member toward an upper portion,
an upper portion of the first cylindrical member protrudes above a rotor fixed to an outer circumferential surface of the rotating shaft;
the discharge pipe includes a second cylindrical member having a constant outer diameter over the entire length, and a different diameter portion extending upward from the second cylindrical member,
Only a lower portion of the second cylindrical member of the discharge pipe protrudes downward from the top wall portion of the housing,
The lower end of the second cylindrical member and the upper end of the shaft tapered portion are disposed in close proximity to each other in a position directly facing each other with only the internal space in the housing interposed therebetween,
a distance L (mm) between an upper end of the shaft tapered portion and a lower end of the second cylindrical member satisfies the following formula (1), when an inner diameter of the second cylindrical member is D (mm).

The rotary compressor according to claim 1 , wherein an inner diameter D of the second cylindrical member satisfies the following formula (2):

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