JP2604835B2 - Rotary compressor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary compressor used in a refrigeration cycle or the like, and particularly relates to a configuration with a small sliding loss.

2. Description of the Related Art FIGS. 7, 8, 9, 10, and 11 show a conventional configuration.
This will be described with reference to the drawings.

Reference numeral 1 denotes a sealed casing, and 2 denotes an electric motor unit, which is connected via a shaft 3 to a machine unit main body 9 constituted by a cylinder 4, a roller 5, a vane 6, a main bearing 7, and an auxiliary bearing 8. The shaft 3 includes a main shaft 3a, a sub shaft 3b, and a crank 3c. In addition, a hole 3d is formed at the center of the shaft 3, and the crank 3
An oil supply hole 3e and an oil supply groove 3f are provided in 3c. 10 is a spring provided on the back of the vane. Reference numerals 11a and 11b denote a suction chamber and a compression chamber in the cylinder 4, each of which includes a roller 5, a vane 6, a main bearing 7, and an auxiliary bearing 8. Reference numeral 12 denotes an oil supply mechanism connected to the shaft 3, which communicates with the hole 3d, the oil supply hole 3e, and the oil supply groove 3f of the shaft 3, and also connects the inner peripheral surface of the roller 5 and the crank.
The main bearing 7 communicates with the space 12a surrounded by the sub bearing 8. Reference numeral 13 denotes a back pressure chamber formed by a back surface opposite to the contact surface of the vane 6 with the roller 5, a syringe 4, a main bearing 7, and a sub bearing 8. The main bearing 7 has a first oil passage 7a.
And a third oil passage 7b, and the vane 6 is also provided with a second oil passage 6a. These oil passages 7a, 7
b and 6a indicate that the vane 6 has the crank rotation angle θ as shown in FIG.
= 0.2π when near the top dead center A, all communicate with each other, and when the vane 6 is near the bottom dead center B when the crank rotation angle θ = π as shown in FIG. 8 and FIG. , Are all closed so that they do not communicate with each other.

Reference numeral 14 denotes a suction pipe, which is an auxiliary bearing 8 and a suction passage 15 for the cylinder 4.
Through the suction chamber 11a. Reference numeral 16 denotes a discharge section which communicates with the inside of the closed casing 1 via a discharge valve (not shown). Reference numeral 17 denotes a discharge pipe which is open into the closed sequence 1. Reference numeral 18 denotes a lubricating oil in which a refrigerant is partially dissolved.

Next, the compression mechanism of the rotary compressor will be described. Refrigerant gas from a cooling system (not shown) is guided through the suction pipe 14 and the suction passage 15 and reaches the suction chamber 11a in the cylinder 4. Refrigerant gas reaching the suction chamber 11a is supplied to the crank 3c of the shaft 3.
In the compression chamber 11b partitioned by the roller 5 and the vane 6 rotatably accommodated in the motor unit 2, the compression is gradually performed by the rotation motion of the shaft 3 accompanying the rotation of the electric motor unit 2. The compressed refrigerant gas is once discharged into the closed casing 1 through the discharge part 16 and the discharge valve, and then discharged to the cooling system through the discharge pipe 17.

Next, the flow of the lubricating oil 18 in which the refrigerant is partially dissolved will be described. The lubricating oil 18 lubricates between the shaft 3 and the main bearing 7 and the sub-bearing 8 via the supply mechanism 12 and the hole 3d and returns to the lower part of the closed casing 1, and a part of the roller 5 is supplied from the oil supply hole 3e and the oil supply groove 3f. And between the crank 3c, and further enters the compression chamber 11b from the end face of the roller 5 through the space 12a, is discharged together with the refrigerant gas, and returns to the lower part of the closed casing 1.

Between the vane 6 and the cylinder 4, when the vane 6 reaches the top dead center, the lubricating oil 18 at the lower part of the closed casing 1 and the back pressure chamber 13 communicate with each other via the oil passages 7a, 7b, 6a. High-pressure lubricating oil 18 flows into the inside. During the reciprocating sliding movement of the vane 6, the leaking vane 6 and the cylinder 4 are lubricated and sealed into the suction chamber 11a and the compression chamber 11b.

By the way, after the high pressure lubricating oil is sucked in the vicinity of the top dead center A, while the vane 6 moves from the top dead center A to the bottom dead center B, the back pressure part B and the lubricating oil 18 at the lower part of the closed casing 1 are connected. The pressure of the back pressure chamber 13 decreases because the volume of the back pressure chamber 13 increases without being able to pass through,
Intermediate pressure P _M next to the high pressure P _d and the low-pressure pressure P _S, while the next moving the bottom dead center B → top dead point A also volume have kept you waiting chamber 13 without communicating decreases the lubricating oil 18 Therefore, the pressure in the back pressure chamber 13 rises again to a high pressure.

Therefore, the pressure in the back pressure chamber 13 is between the high pressure _Pd and the intermediate pressure _PM.
Limit pressure P _C at which the vane 6 and the roller 5 fluctuate between
Compared to the case of always high pressure P _d the back pressure of the vane 6 to greater than sliding loss reduces the contact load of the vane 6 and the roller 5 is lowered, and there is the effect of the reliability is improved Was. For example, it is disclosed in JP-A-61-106992.

In such a conventional configuration, a part of the lubricating oil once flowing into the back pressure chamber flows out to the suction chamber or the compression chamber through the gap between the vane and the cylinder. Since the pressure is small, this amount is small, and the pressure in the back pressure chamber becomes a high pressure at the top dead center. Therefore, even if the back pressure chamber communicates with the lubricating oil portion, lubricating oil is hardly supplied. Therefore, there is little lubricating oil in and out of the back pressure chamber, the temperature of the lubricating oil rises, the temperature of the sliding part between the vane and the cylinder rises, and there are problems such as poor lubrication due to a decrease in viscosity. There was a problem in terms of reliability that accumulated in the room and caused seizure. Also, in specifications such as small eccentricity, the volume of the back pressure chamber at the top dead center and bottom dead center is small, and the intermediate pressure P _M
But there is a problem that does not fall enough to approach the P _C.

Furthermore, in the stroke to the bottom dead center → top dead center, requires extra torque for pressure subjected to compression action in the back pressure chamber rises to P _M → P _d, reduction effect is small challenges sliding loss there were.

The present invention solves the disadvantages of the above conventional example,
By lowering the pressure in the back pressure chamber, especially near the bottom dead center, the torque required for compression from bottom dead center to top dead center is reduced, performance is improved, and lubricating oil in the compression chamber is transferred to the back pressure chamber. The purpose is to provide reliability and ensure reliability.

Means for Solving the Problems The present invention has a communication path having one end communicating with the back pressure chamber and the other end intermittently communicating with the compression chamber with the eccentric rotation of the roller.

Effect of the Invention According to the above configuration, when the back pressure chamber communicates with the compression chamber during the compression stroke, the refrigerant and the lubricating oil in the back pressure chamber flow out, the pressure in the back pressure chamber decreases, and new lubrication occurs in the communication section. Some oil is supplied. In particular, by communicating the back pressure chamber and the compression chamber at the bottom dead center position where the volume of the back pressure chamber is the largest,
The pressure from the bottom dead center to the top dead center falls, the compression torque is reduced, and the lubricating oil for the back pressure guide is replaced little by little, so that the reliability can be improved.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. The same parts as those in the conventional example are denoted by the same reference numerals, and detailed description will be omitted. Reference numeral 19 denotes a main bearing which houses the main shaft 3a as in the conventional case. The main bearing 19 constitutes a suction chamber 11a and a compression chamber 11b, and is a space surrounded by the crank 3c and the roller 5.
Make up 12a. Reference numeral 20 denotes a back pressure chamber.

Reference numeral 21 denotes a communication passage provided in the main bearing 19, the first opening 21a always communicating with the back pressure chamber 20, and the second opening 2a.
1b is installed at a position that is opened and closed as the roller 5 rotates.

That is, when the roller 5 is in the vicinity of the bottom dead center B of the crank rotation angle θ = π, the second opening 21b is connected to the compression chamber 11b.
Is in communication with When the crank rotation angle θ is at a point other than the vicinity of the point B, the second opening 21b is
Is closed at the end face.

As before, the refrigerant gas is sucked into the suction chamber 11a through the suction pipe 14 and the suction passage 15, and is discharged through the discharge section 16, the closed casing 1, and the discharge pipe 17 after being compressed in the compression chamber 11b. Is done.

At this time, the back pressure chamber 20 is in the vicinity of the bottom dead center B of the crank rotation angle theta = [pi, at an intermediate pressure in the low-pressure pressure P _S and the high pressure P _d, lower than the intermediate pressure P _M in the prior art, a limit compression chamber 11 where the pressure to a slightly higher intermediate pressure P _M 'than the pressure P _C is rising
The position of the second opening 21b is set so as to communicate with b. As a result, while the second opening 21b communicates with the compression chamber 11b, the pressure in the back pressure chamber 20 decreases to the intermediate pressure P _M ′, and a part of the lubricating oil in the back pressure chamber 20 decreases. Then, the lubricating oil in the compression chamber 11b flows in. At other points of the crank rotation angle, the second communication passage 21b is closed by the end face of the roller 5, so that the back pressure chamber between them is provided.
The pressure at 20 changes with the change in volume of the back pressure chamber 20 due to the reciprocating motion of the vane 6.

Therefore, the pressure in the back pressure chamber 20 is slightly higher than P _C is the limit pressure vane 5 and the vane 6 are separated, the conventional intermediate pressure
Well below the P _M intermediate pressure P _M 'and the high pressure P _d slightly below the high pressure P _d' will be controlled between.

Therefore, the contact load between the vane 6 and the roller 5 is reduced in the entire range of the crank rotation angle θ, and the sliding loss is reduced as compared with the related art. Further, when the back pressure chamber 20 and the compression chamber 11b communicate with each other, the lubricating oil flows in and out, and a flow of the lubricating oil is formed, whereby poor lubrication due to a rise in temperature can be prevented, and seizure can also be prevented.

Also, for example, after introducing high-pressure lubricating oil in the closed casing into the back pressure chamber, the low-pressure or intermediate-pressure chamber is connected to the back pressure chamber to reduce the back pressure and supply the lubricating oil to the back pressure chamber. Compared with the method, the number of short circuits between high and low pressures can be reduced, and the volume efficiency can be improved.

Effect of the Invention As is clear from the above description, the present invention provides a cylinder and
A main shaft and a sub-bearing fixed to both ends of the cylinder, a shaft rotatably housed in the main bearing and the sub-bearing and having a crank, a roller fitted to the crank of the shaft and rotating eccentrically in the cylinder, and a groove in the cylinder. A reciprocating motion and a contact with a roller to divide the inside of the cylinder into a suction chamber and a compression chamber, a back pressure chamber formed on the back surface of the vane, and a first opening communicating with the back pressure portion, Since the second opening has a communication path intermittently communicating with the compression chamber due to the eccentric rotation of the roller, the sliding loss is reduced, the volume efficiency is good, the lubrication is poor, and the seizure is poor. Thus, a compressor with high efficiency and high reliability can be provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a rotary compressor showing one embodiment of the present invention, FIG. 2 is a view taken along the line II-II 'of FIG. 1 at a crank angle θ = 0,2π, and FIG. FIG. 4 is also an arrow view at θ = π / 2, FIG. 4 is an arrow view at θ = π, FIG. 5 is an arrow view at θ = 3 / 2π, and FIG. FIG. 1 is a diagram showing the open / close state of the communication passage and a change curve of the back pressure chamber pressure in the embodiment of FIG. 1, FIG. 7 is a longitudinal sectional view of a conventional rotary compressor, and FIG.
FIG. 9 is a sectional view at the top dead center of the conventional back pressure chamber, FIG. 10 is a sectional view at the bottom dead center of the conventional back pressure chamber, FIG. FIG. 3 is a diagram showing a conventional oil passage opening / closing state and a change curve diagram of a back pressure chamber pressure. 3 ... shaft, 3c ... crank, 4 ... cylinder, 5
Roller, 6 Vane, 8 Sub bearing, 11a Suction chamber, 11b Compression chamber, 19 Main bearing, 20 Back pressure chamber, 2
1 ... communication passage, 21a ... first opening, 21b ... second opening.

Claims (1)

(57) [Claims] 1. A cylinder, a main bearing and a sub-bearing fixed to both ends of the cylinder, a shaft rotatably housed in the main bearing and the sub-bearing, having a crank, and fitted to a crank of the shaft. A roller that eccentrically rotates in the cylinder, a vane that reciprocates in the groove of the cylinder and divides the interior of the cylinder into a suction chamber and a compression chamber by coming into contact with the roller, and a back pressure formed on the back surface of the vane. A rotary compressor having a chamber and a communication path in which a first opening communicates with the back pressure chamber and a second opening intermittently communicates with the compression chamber with eccentric rotation of the roller.