JPH11132178A - Rotary compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary compressor having high pump efficiency and high durability by keeping delivering flow from a delivering port and simultaneously reducing volume of the delivering port. SOLUTION: An eccentric rotor 20 fixed to a rotational shaft 19 eccentrically rotates in a cylinder chamber consisting of a cylinder 21, an upper bearing 22 which is fixed to the upper part of the cylinder 21 and supports the rotational shaft 19 above the eccentric rotor 20, and a lower bearing 23 which is fixed to the lower part of the cylinder 21 and supports the rotational shaft 19 below the eccentric rotor 20. In a rotary compressor which delivers gas suctioned from a suction port 29 by pressing up a delivery valve 33 from a delivering port 30, a thin part 22a is provided for the upper bearing 22 forming a wall surface of the cylinder chamber, the delivering port 30 is formed to penetrate through this thin part 22a, and a spot facing hole 22b is formed around the delivering port 30 facing the cylinder chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary compressor used for a refrigeration system or an air conditioner, for example.

[0002]

2. Description of the Related Art A conventional rotary compressor includes a cylindrical housing, a motor disposed in the housing, and a hermetic rotary compression mechanism driven by the motor to compress gas (fluid to be conveyed). It is comprised including.

As shown in FIG. 5, for example, a rotary compression mechanism includes a rotary shaft 1 joined to a drive shaft of a motor, an eccentric rotor 2 fixed to an eccentric position with respect to the rotary shaft 1, and an eccentric rotor 2. Cylinder 3 inserted into the housing with eccentric rotor 2 arranged in a space with a circular cross section that slides on the outer peripheral surface at one location.
An upper bearing 4 fixed to the upper end surface of the cylinder 3 and rotatably supporting the rotary shaft 1 above the eccentric rotor 2
And a lower bearing 5 fixed to the lower end surface of the cylinder 3 and rotatably supporting the rotary shaft 1 below the eccentric rotor 2.

A suction port 7 for sucking gas toward a suction chamber formed in a cylinder chamber 6 is opened in the cylinder 3, and a gas flows from a compression chamber formed by turning over the suction chamber to the upper bearing 4. The eccentric rotor 2 is accommodated in a cylinder chamber 6 formed by closing the cylinder 3 with the upper bearing 4 and the lower bearing 5 from above and below.

The cylinder chamber 6 is provided on one side of the blade by pressing the tip of a blade (not shown) against the outer peripheral surface of the eccentric rotor 2, and is connected to the suction chamber communicating with the suction port 7 and the other side of the blade. And a compression chamber communicating with the discharge port 8.

[0006] The discharge port 8 is formed as a circular hole in a plan view penetrating the upper bearing 4, and a discharge valve 9 that is opened when a pressure equal to or larger than a predetermined magnitude is received on the upper surface of the discharge port 8. Is provided.

In the rotary compressor shown in the figure, the gas continues to flow out of the discharge port 8 during the process in which the eccentric rotor 2 gradually narrows the compression chamber and closes to the discharge port 8, but the eccentric rotor 2 connects the discharge port 8 to the discharge port 8. When passing, the end face of the eccentric rotor 2 closes the discharge port 8, and the discharge port 8 is in a state in which gas less than the pressure required to push up the discharge valve 9 is sealed. This discharge port 8
Gas starts to expand after the eccentric rotor 2 passes, and decreases the pressure until the pressure reaches the pressure in the suction chamber (the pressure at the suction port).

The actual volume of the compression chamber is considered to be the sum of the volume of the portion partitioned by the eccentric rotor 2 in the cylinder chamber 6 and the volume of the discharge port 8. Therefore, if the volume of the discharge port 8 is large, extra time is required to increase the actual gas pressure in the compression chamber to a pressure at which the discharge valve 9 can be pushed up.

Therefore, in order to reduce the volume while keeping the discharge flow rate from the discharge port 8 constant, it is necessary to shorten only the depth (length of the flow path) without changing the opening area of the discharge port 8. For that purpose, it is effective to reduce the thickness of the portion of the upper bearing 4 where the discharge port 8 is provided.

[0010]

However, simply reducing the wall thickness not only reduces the strength of the bearing, but also causes the thin wall portion to be elastically deformed under the influence of the gas pressure fluctuation, and the end face of the eccentric rotor. Is expected to hinder stable rotation of the eccentric rotor. For this reason, in the conventional rotary compressor, the volume of the discharge port has to be larger than a certain size, which is one of the factors that hinders an improvement in pump efficiency.

The present invention has been made in view of such circumstances, and by reducing the volume of a discharge port while keeping the discharge flow rate from the discharge port constant, high pump efficiency and excellent durability are achieved. It is intended to provide a rotary compressor.

[0012]

In order to solve the above-mentioned problems, an eccentric rotor fixed to a rotary shaft rotates a rotary shaft above a cylindrical cylinder and an eccentric rotor fixed to an upper portion of the cylinder. An upper bearing that freely supports,
An eccentric rotational movement is made in a cylinder chamber comprising a lower bearing fixed below the cylinder and rotatably supporting a rotary shaft below the eccentric rotor, and sucks the fluid to be conveyed from a suction port opened toward the cylinder chamber. In a rotary compressor, which compresses together with the same and pushes up and discharges a discharge valve from a discharge port provided in a cylinder chamber, a thin portion having a thinner thickness is provided on a bearing provided with a discharge port than other portions. A discharge port penetrating toward the cylinder chamber is provided in the thin portion. As a result, even if the opening area of the discharge port is the same size as the conventional one, the flow path is shortened, so that the volume is reduced, and the actual volume of the compression chamber including the discharge port is reduced.

Further, a counterbore is formed in the thin portion around the discharge port facing the cylinder chamber. Thereby, even if the thin portion is elastically deformed inward due to the influence of the gas pressure fluctuation by forming the counterbore, the stable rotation of the eccentric rotor can be obtained without contacting the end surface of the eccentric rotor. In addition, there is no problem that a part of the end face of the eccentric rotor is extremely worn and the airtightness of the cylinder chamber is impaired. The discharge port may be provided on either the upper bearing or the lower bearing or on both.

If the thickness of the thin portion is too small, the strength of the bearing around the discharge port cannot be ensured. If the thickness is too large, the capacity of the discharge port necessarily increases, so that the pump efficiency cannot be improved. . Therefore, by setting the thickness to be in the range of 1.5 mm or more and 3 mm or less, desired high pump efficiency can be obtained while securing sufficient strength for the bearing.

If the counterbore is too shallow, contact between the thin portion and the end face of the eccentric rotor cannot be avoided. If the counterbore is too deep, the volume of the counterbore increases, and even if the discharge port wall thickness is set appropriately. The effect is halved. Therefore, by setting the depth of the counterbore in the range of 10 μm or more and 200 μm or less, stable rotation of the eccentric rotor and high pump efficiency can be obtained.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a rotary compressor according to the present invention will be described with reference to FIGS. The rotary compressor has a cylindrical housing 11 as shown in FIG.
And a motor 12 disposed in the housing 11, and a hermetically sealed rotary compression mechanism 13 driven by the motor 12 to compress refrigerant gas (fluid to be conveyed).

The housing 11 has a hollow cylindrical shape in which a bottom part 11b and a lid part 11c are welded and closed on the upper and lower sides of a cylindrical part 11a. One end of a suction pipe 14 connected to the rotary compression mechanism 13 is provided in the cylindrical part 11a in a penetrating state, and a discharge pipe 15 connected to a cooling mechanism (not shown) is provided in the lid part 11c in a penetrating state. Have been.

In the motor 12, the stator 16 has the housing 1
1 and the drive shaft 1 to which the rotor 17 is fixed
8 extends toward the rotary compression mechanism 13 located below.

The rotary compression mechanism 13 includes a rotary shaft 19 press-fitted into the lower end of a hollow drive shaft 18, an eccentric rotor 20 fixed at an eccentric position with respect to the rotary shaft 19, and one outer circumferential surface of the eccentric rotor 20. A cylinder 21 welded to the housing 11 in a state having a space having a circular cross section which slides at a location and the eccentric rotor 20 is arranged in this space;
Upper bearing 2 fixed to the upper end surface of cylinder 21 and rotatably supporting rotary shaft 19 above eccentric rotor 20
2 and the eccentric rotor 2 fixed to the lower end face of the cylinder 21
0 and a lower bearing 23 that rotatably supports the rotating shaft 19 below the lower shaft 0.

The rotary shaft 19 is supported with its lower end protruding from the lower bearing 23, and an oil pump is constituted by a spirally formed blade 24 inside the hollow, and is provided at the bottom of the housing 11. Is the oil sump 25
Are formed.

The eccentric rotor 20 is housed in a cylinder chamber 26 formed by closing a space provided in a cylinder 21 with an upper bearing 22.

As shown in FIG. 2, a slot hole 21a is formed in the inner surface of the cylinder 21 forming the cylinder chamber 26, and the slot hole 21a has one side substantially equal in length to the thickness of the eccentric rotor 20. The blade 27 is inserted so that one side of the blade 27 can protrude and retract from the cylinder chamber 26, and a spring body 28 that pushes the blade 27 toward the cylinder chamber 26 is provided behind the blade 27. The blade 27 is a plate-like member having one side substantially equal to the length in the thickness direction of the eccentric rotor 20, and is biased by the spring body 28 so that one side thereof is pressed against the outer peripheral surface of the eccentric rotor 20. It has become.

Further, the cylinder 21 forming the cylinder chamber 26 is provided with a suction port 29 which is located forward of the blade 27 in the rotation direction of the eccentric rotor 20 and communicates with the suction pipe 14. A discharge port 30 which is located rearward in the rotation direction of the eccentric rotor 20 and communicates with the discharge pipe 15 is opened. The cylinder chamber 26
When the tip of the blade 27 is pressed against the outer peripheral surface of the eccentric rotor 20, the suction port provided on one side of the blade 27 and communicating with the suction port 29 and the discharge port 30 provided on the other side of the blade 27 are provided. And a compression chamber communicating with the compression chamber.

The discharge port 30 is formed as a circular hole in plan view that penetrates the upper bearing 22 and communicates with an upper muffler chamber 32 formed by a cover 31 that covers the upper surface of the upper bearing 22. The discharge port 30 located on the upper muffler chamber 32 side is provided with a discharge valve 33 that is opened when a pressure equal to or more than a predetermined value is received.

As shown in FIG. 3, the upper bearing 22 is provided with a thin portion 22a which is thinner than other portions around the discharge port 30. The thin portion 22a is the upper bearing 22
The discharge port 30 is formed so as to penetrate the thin portion 22 a toward the cylinder chamber 26.

A counterbore 22b facing the cylinder chamber 26 is formed in the thin portion 22a at a uniform depth. The counterbore 22b is formed concentrically with the discharge port 30 so as to extend in substantially the same range.

The rotary compressor is provided with an accumulator 34 for separating a small amount of lubricating oil contained in the gas from the gas flowing through the cooling mechanism.

The accumulator 34 has a cylindrical container 35 connected to a pipe through which gas flows. Inside the cylindrical container 35, the other end of the suction pipe 14 is provided in a penetrating state, and is upward. Has been extended towards.

The process of operating the rotary compressor configured as described above to compress and convey gas will be described. First, when the motor 12 is operated, the rotating shaft 19 connected to the drive shaft 18 rotates, and the eccentric rotor 20 starts rotating. The eccentric rotor 20 performs eccentric rotational movement in the cylinder chamber, and accordingly, gas is sucked from the suction pipe 14 into the suction chamber, and at the same time, gas already sucked into the compression chamber is gradually compressed. The compressed gas is supplied to the discharge port 30
Then, the discharge valve 33 is pushed up to flow into the upper muffler chamber 32, and its pulsating component is removed. The gas that has flowed into the upper muffler chamber 32 passes through a not-shown through hole formed in the cover 31 and flows below the motor 12 and expands, whereby the pulsating component is further removed. The gas flowing below the motor 12 passes through an air gap between the stator 16 and the rotor 17 and a gas passage formed between the stator 16 and the housing 11 and flows above the motor 12 to expand. Thereby, the pulsation component is further removed. The gas flowing above the motor 12 flows into the discharge pipe 15,
It is transported toward a cooling mechanism (not shown).

The gas flowing through the cooling mechanism flows into the accumulator 34 to separate lubricating oil dispersed as fine oil droplets in the gas.

The lubricating oil accumulated in the oil sump 25 is moved upward in the rotary shaft 19 by the pumping action generated by the rotational movement of the blade 24, and is moved from a supply passage (not shown) into the cylinder chamber 26. Is supplied to the sliding portion between the eccentric rotor 20 and the cylinder 21 and is jetted from the upper end of the rotating shaft 19 to cool the rotary compression mechanism 13.

In the rotary compressor configured as described above, the upper bearing 22 is provided with the thin portion 22a, and the thin portion 22a is provided with the discharge port 30 penetrating toward the cylinder chamber 26. The flow path of the discharge port 30 is configured to be short, and the volume is reduced as compared with the related art.

Further, in the upper bearing 22, the thin portion 22a is affected by the pressure fluctuation of the flowing gas so that the cylinder portion 26a
May be elastically deformed to the side, but since the thin portion 22a is provided with the bore hole 22b facing the cylinder chamber 26, a clearance for avoiding contact with the end surface of the eccentric rotor 20 is secured, Even if the portion 22a is elastically deformed, it does not contact the end face of the eccentric rotor 20.

FIG. 4A shows the relationship between the thickness H of the thin portion 22a and the amount of deflection た generated in the thin portion 22a with respect to the thickness of the thin portion 22a. FIG. 4B shows the relationship with the stress σ acting on the thin portion 22a when the thin portion 22a is bent.

According to FIG. 4A, the thickness H of the thin portion 22a is shown.
Is larger than 3 mm, the amount of deflection χ becomes very small, so the counterbore hole 22b becomes unnecessary, and the thickness H becomes 1.5 mm.
When it is smaller than mm, the deflection amount χ rapidly increases.

According to FIG. 4 (b), if the thickness H of the thin portion 22a is large, the stress is small and does not reach the fatigue limit of the sintered material forming the bearing at all, but the thickness H is 1.5 mm. If it becomes smaller, the stress σ acts on the thin portion 22a beyond the fatigue limit of the sintered material.

Therefore, in the rotary compression mechanism 13, the thickness H of the thin portion 22a is set in the range of 1.5 mm or more and 3.0 mm or less, and the upper bearing 22 provided with the discharge port 30 has sufficient strength. Secured. In addition, since the volume of the discharge port 30 is reduced as compared with the related art, high pump efficiency can be obtained.

FIG. 4A shows that the maximum deflection χ when the thickness H of the thin portion 22a is set in the range of 1.5 mm or more and 3.0 mm or less is slightly smaller than 10 μm. Considering this, the depth δ of the counterbore 22b is set to 10 μm.
Is set to the lower limit, and a clearance sufficient to avoid contact between the thin-walled portion 22a that is elastically deformed and the end surface of the eccentric rotor 20 is secured. Also, the depth δ of the counterbore hole 22b
Is set in the range of 200 μm or less, and the counterbore 2
Since the volume of the space formed by 2b is kept small, the effect of providing thin portion 22a is sufficiently maintained.

Therefore, according to the rotary compressor configured as described above, it is possible to improve the pump efficiency of the rotary compression mechanism 13 while maintaining the stable rotation of the eccentric rotor 20.

Incidentally, the rotary compressor shown in the above embodiment has the discharge port provided in the upper bearing, but the discharge port may be provided in the lower bearing. Also,
The upper and lower bearings may each be provided with a discharge port.

[0041]

As described above, according to the rotary compressor of the present invention, a thin portion is provided on one or both of the upper bearing and the lower bearing, and the thin portion penetrates toward the cylinder chamber. Since the discharge port is provided, the flow path of the discharge port is configured to be short, and the volume is reduced as compared with the related art. Moreover, since the counterbore hole is formed in the thin portion around the discharge port facing the cylinder chamber, a clearance for avoiding contact with the end face is secured. This makes it possible to improve the pump efficiency of the rotary compression mechanism while maintaining stable rotation of the eccentric rotor.

The thickness of the thin portion is 1.5 mm or more and 3.0 mm
Since it is set in the following range, the volume of the discharge port is reduced as compared with the related art while ensuring sufficient strength for the bearing provided with the discharge port. As a result, the pump efficiency can be improved while the rotary compression mechanism has sufficient durability.

Since the depth of the counterbore is set to a range of 200 μm or less, the volume of the space formed by the counterbore can be reduced, and the volume of the space formed by the counterbore can be reduced. Therefore, the effect of reducing the volume of the discharge port by providing the thin portion can be fully utilized.

In addition, since the depth of the counterbore hole is set to a range of 10 μm or more, a sufficient clearance for avoiding contact with the end surface of the eccentric rotor due to elastic deformation of the thin portion is secured, and the eccentric rotor Can achieve stable rotation.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing one embodiment of a rotary compressor according to the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a cross-sectional view of a main part of the periphery of the discharge port 30 viewed from the side.

4A is a table showing the relationship between the thickness H of the thin portion 22a and the amount of deflection 生 じ る generated in the thin portion 22a with respect to the thickness, and FIG. 4B is a diagram showing the thickness of the thin portion 22a. 6 is a table showing a relationship between H and a stress σ acting on the thin portion 22a when the thin portion 22a is bent.

FIG. 5 is a side sectional view showing an example of a rotary compression mechanism provided in a conventional rotary compressor.

[Explanation of symbols]

 Reference Signs List 11 housing 12 motor 13 rotary compression mechanism 14 suction pipe 15 discharge pipe 19 rotation shaft 20 eccentric rotor 21 cylinder 22 upper bearing 22a thin portion 22b counterbore hole 23 lower bearing 26 cylinder chamber 29 suction port 30 discharge port 33 discharge valve

Claims (4)

[Claims] An eccentric rotor fixed to a rotating shaft includes a cylindrical cylinder, an upper bearing fixed to an upper portion of the cylinder and rotatably supporting the rotating shaft above the eccentric rotor, and an upper bearing at a lower portion of the cylinder. An eccentric rotational movement is made in a cylinder chamber comprising a fixed and lower bearing rotatably supporting a rotary shaft below the eccentric rotor, and sucks and compresses the fluid to be conveyed from a suction port opened toward the cylinder chamber. A rotary compressor that pushes up and discharges a discharge valve from a discharge port also provided in a cylinder chamber, wherein the discharge port is provided in one or both of the upper bearing and the lower bearing and a wall surface of the cylinder chamber. And a counterbore is formed around the discharge port facing the cylinder chamber. Rotary compressor according to claim and. 2. The thickness of the thin portion is 1.5 mm or more.
2. The rotary compressor according to claim 1, wherein the rotary compressor is set to a range of 0 mm or less. 3. The rotary compressor according to claim 1, wherein the depth of the counterbore is set to a range of 200 μm or less. 4. The counterbore hole has a depth of not less than 10 μm and not more than 20 μm.
3. The rotary compressor according to claim 1, wherein the rotary compressor is set to a range of 0 [mu] m or less.