JPH03145592A - Compressor - Google Patents

Abstract

PURPOSE:To release a piston from thrust force by forming a pressure closing chamber between the end face portion of the piston and the supporting member of a bearing, etc., opposite thereto, and leading opposite fluid pressure resisting against the thrust force generated in the piston from a compressor unit to the pressure closing chamber. CONSTITUTION:When a cylinder 7 together with a rotor 6 are rotated by supply ing electricity to an electric-motor unit 3, a piston provided with helical blades 17 arranged on the outer circumference thereof is eccentrically rotated in such a condition that a part of the outer circumference makes contact with the inner circumference of the cylinder 7. And refrigerant gas sucked from a suction hole 21 is compressed and discharged from a discharge hole 27. In this case, both ends of the piston 11 and bearings 8, 9 facing thereto are slightly parted from each other, ring like packings 19 are fitted to surround each parted portion for defining pressure closing chambers 20a, 20b. Lubricating oil in an oil introduc ing passage 28 is led to the pressure closing chamber 20a and the pressure of sucked refrigerant is led via a passage gas outlet 26 to the pressure closing chamber 20b.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a compressor for compressing compressed gas such as refrigerant gas in a refrigeration cycle.

(Prior art) Compressors used in refrigeration cycles, such as air conditioners and refrigerators, generally use a reciprocating type that uses a reciprocating piston, or a rotary type that rotates a disk-shaped piston eccentrically within a cylinder. There is.

However, all of these types of compressors have the disadvantage that the structure of the drive section, such as the crankshaft that transmits rotational force to the compressor, and the compressor section are complex, and the number of parts is large.

Therefore, recently, a compressor called a helical blade type has been proposed. The compressor section is constructed by combining a cylindrical cylinder with one end on the suction side and the other end on the discharge side, and a cylindrical piston with a spiral blade on its outer circumferential surface. ing.

Specifically, the piston is provided with a groove on its outer circumferential surface, the pitch of which decreases from the suction side to the discharge side.
A spiral blade with an outer diameter that corresponds to the inner diameter of the cylinder is fitted into this structure so that it can move in and out. This piston is inserted into the cylinder and placed so that the blade is in contact with the inner peripheral surface of the cylinder, and the entire piston is positioned eccentrically from the axis of the cylinder so that a portion of the outer peripheral surface is in contact with the inner peripheral surface of the cylinder. Place it in Both ends of the cylinder are supported by bearings so as to be rotatable around the axis. Both ends of the piston are also rotatably supported using the same bearings so that they can pivot relative to the cylinder. Furthermore, between the piston and cylinder,
It is equipped with an Oldham mechanism that rotates the piston synchronously with the rotation of the cylinder.

In such a helical blade type compressor, the cylinder rotates in the normal direction around its axis by rotating the cylinder. Further, the piston rotates around the axis of the cylinder while maintaining contact with the inner circumferential surface of the cylinder, and rotates in synchronization with the rotation of the cylinder. Then, the volume of the crescent-shaped compression chamber inside the cylinder partitioned by the blades changes continuously in the direction of contraction. As a result, refrigerant gas (compressed gas) is sucked in from the suction side of the cylinder. This refrigerant gas is then compressed while moving to the discharge side of the cylinder, and then at the discharge side, a helical blade compressor sucks in from one end of the cylinder and discharges the compressed gas from the other end. Due to its structure, a pressure difference (suction pressure, discharge pressure) occurs at both ends of the piston.

Therefore, this pressure difference generates a force in the thrust direction, that is, an excessive force in a direction that pushes the piston toward the suction side.

Since this thrust force acts as a force that impairs the rotation of the piston, the operation of the compressor is not smooth.

This invention was made with attention to these circumstances,
The aim is to provide a compressor that allows the piston to be released from thrust forces.

[Configuration of the Invention (Means for Solving the Problems)] In order to achieve the above object, the compressor of the present invention creates pressure between the end face of the piston and the part of the supporting member that supports the piston. While forming a sealed room,
A means is provided for guiding an opposite fluid pressure from the compressor section to the pressure-tight chamber to counteract the thrust force generated in the piston.

(Function) According to the compressor of the present invention, in the pressure sealed chamber,
By introducing fluid pressure that resists the force in the thrust direction generated on the piston, the differential pressure that caused the generation of thrust force is eliminated, and the forces at both ends of the piston are balanced. In other words, the piston is released from the thrust force.

Therefore, the piston can rotate smoothly,
The compressor can operate smoothly.

(Example) The present invention will be described below based on an example shown in FIGS. 1 and 2. FIG. 1 shows a hermetic compressor for refrigerant gas used, for example, in a refrigeration cycle, to which the present invention is applied. The compressor 1 includes, for example, a horizontal closed case 2, and a motor section 3 and a compressor section 4 disposed within the closed case 2. The electric motor section 3 includes a substantially annular stator 5 fixed to the inner surface of the sealed case 2 and an annular rotor 6 provided inside the stator 5.

The compressor section 4 has a cylindrical cylinder 7. The rotor 6 is coaxially fixed to the outer peripheral surface of the cylinder 7. Further, both ends of the cylinder 7 are rotatably fixed to bearings 8 and 9 (corresponding to supporting members) fixed to the inner surface of the end portion of the closed case 2. That is, the bearings 8 and 9 have a fitting portion 8a on the tip side corresponding to the inner diameter of the cylinder.
, 9a, and has installation parts 8b and 9b installed on the wall of the cylinder 7 on the base side, and one end of the cylinder is rotatably inserted into each insertion part 8a and 9a of the bearing 8.9. has been done. Thereby, both ends of the cylinder 7 are hermetically closed and rotatably supported.

A cylindrical piston 11 having an outer diameter smaller than the inner diameter of the cylinder 7 is disposed inside the cylinder 7 along the axial direction of the cylinder 7 . This piston 11 is arranged so that its central axis A is eccentrically downward in FIG. 1 by a distance Me with respect to the central axis B of the cylinder 7. With this arrangement, a part of the outer circumferential surface of the piston 11 is brought into line contact with the inner circumferential surface of the cylinder 7.

A support shaft portion 12 is provided at both axial ends of the piston 11.
a and 12b are provided in a protruding manner. And these support shaft parts 1
2a and 12b are the fitting portions 8a of the bearings 8 and 9, respectively;
The piston 11 is rotatably inserted into bearing holes 8c, 9c formed in the cylinder 9a, and supports the piston 11 in a rotatable manner relative to the cylinder 7.

Further, an Oldham mechanism 10 is provided between, for example, one support shaft portion 12a of the piston 11 and the peripheral wall of the cylinder 7 facing thereto. The Oldham mechanism 10 includes, for example, a prism part 13 having a square cross section formed on the base side of the support shaft part 12H, and an Oldham ring 15 in which a rectangular long hole 14 is bored into the prism part 13. The ring 15 is slidable only in the longitudinal direction. Furthermore, this Oldham ring 15 is fixed to the peripheral wall of the cylinder 7 with a pin or the like so that it can slide freely only in the radial direction perpendicular to the longitudinal direction of the elongated hole 14, and the piston 11 is attached to the cylinder 7 in the radial direction of the cylinder 7. It has a structure in which it is eccentrically connected to the With this Oldham mechanism 10, when the electric motor section 3 is energized to rotate the cylinder 7, the rotational force of the cylinder 7 is transmitted to the piston 11 via the Oldham ring 15. That is, the piston 11 internally rotates (turns while rotating) within the cylinder 7 with a portion of the piston 11 in line contact with the inner surface of the cylinder 7 .

Further, a spiral groove 16 is formed on the outer peripheral surface of the piston 11 along the axial direction of the piston 11. The pitch of the groove portions 16 is gradually reduced from the left side to the right side in the drawing, that is, from the suction side to the discharge side of the cylinder 7. A spiral blade 17 is fitted into this groove 16. The thickness of this blade 17 is almost the same as the width of the spiral groove 16, and each part of the blade 17 is connected to the groove 16 by the piston 11.
It is designed to be able to freely move forward and backward (in and out) along the radial direction. Further, the blade 17 has an outer diameter corresponding to the inner diameter of the cylinder 7, and the entire outer peripheral end is
is in contact with the inner peripheral surface of

Thereby, the blade 17 slides on the inner circumferential surface of the cylinder 7 with the outer circumferential surface being in close contact with the inner circumferential surface of the cylinder 7. And this blade 1
7 partitions the space between the inner circumferential surface of the cylinder 7 and the outer circumferential surface of the piston 11 into a plurality of compression chambers 18 . That is, each working chamber 18 is formed between two adjacent windings of the blade 17. In addition, its shape is similar to that of blade 1.
It has a substantially crescent shape extending along the line 7 from one contact point between the piston 11 and the inner circumferential surface of the cylinder 7 to the next contact point. Due to the pitch of the blades 17, the volume of the compression chamber 18 gradually decreases from the suction side to the discharge side of the cylinder 7.

Also, between the end face of the suction side of the piston 11 and the fitting end of the bearing 8 on the suction side opposite thereto, and the piston 1
There is a slight distance between the end face of the discharge side of the bearing 1 and the tip of the insertion portion of the bearing 9 on the discharge side opposing thereto. On the outer circumferential side of these separation parts, a sealing member surrounding the separation parts,
For example, a ring-shaped packing 19 with excellent wear resistance is attached, and a pressure sealed chamber 20a,
20b. That is, the pressure sealed chambers 20a and 20b on the suction side and the discharge side are both connected to the piston 11.
, the ends of the shafts of the bearings 8 and 9 opposing this, and the suction side support shaft portion 12a.

12b, and a bearing hole 8c opposite thereto.

It is composed of a space surrounded by the bottom surface of 9C and a closed space formed by a gap between the sliding parts of the support shafts 12a and 12b communicating with this space.

As shown in FIG. 2, a suction hole 21 extends axially through the inside of the bearing 8 located on the suction side of the cylinder 7. One end of this suction hole 21 opens into the inside of the cylinder 7. A suction pipe 22 connected to a refrigeration cycle (not shown) is connected to the other end of the suction hole 21, and is formed between a bearing 8 constituting the suction end side of the cylinder 7 and the suction side end of the blade 17. The refrigerant can be introduced into the space 23 where the refrigerant is located.

Further, a gas inlet 24 is opened on the outer peripheral surface of the cylinder 7 facing the space 23 . And this gas inlet 24
As shown in FIG. 2, it communicates with a gas outlet 26 opened in the shaft end surface of the discharge side support shaft portion 12b via a passage 25 provided along the axial direction inside the piston 11. The fluid pressure that resists the force in the thrust direction generated in the piston 11, that is, the pressure of the suction refrigerant, can be guided to the pressure sealed chamber 20b on the discharge side.

A discharge hole 27 is bored inside the other bearing 9 . One end of this discharge hole 27 communicates with the discharge end side inside the cylinder 7 . The other end of the discharge hole 27 is connected to the closed case 2.
It opens into the inside of the case 2 and discharges compressed gas into the sealed case 2.

Further, an oil introduction passage 28 is bored inside the piston 11 along the central axis A thereof. One end of this oil introduction path 28 communicates with the bottom of the spiral groove 16 on the discharge side. The other end opens into an oil reservoir 2a formed at the bottom of the sealed case 2 via a through hole 29 formed in the suction side bearing 8 and an introduction pipe 30. As a result, sealed case 2
When the pressure inside increases due to the discharged gas, the lubricating oil 31 stored in the oil reservoir 2a flows into the inlet pipe 30. The oil is introduced into the space between the bottom of the spiral groove 16 and the blade 17 through the through hole 29 and the oil introduction path 28 .

At the same time, the lubricating oil 31 is transferred to the pressure sealed chamber 20 on the suction side.
It is designed so that it can be introduced into a. In other words, lubricating oil 3
1 as a transmission medium, fluid pressure that resists the force in the thrust direction generated in the piston 11, that is, the pressure of the discharged refrigerant, is introduced into the pressure sealed chamber 20a on the suction side, as described above.

Each pressure sealed chamber 20a defined by one packing
, the pressure receiving area S1 in the direction perpendicular to the axial center of the piston 11 is the cross section 11a S 2 and r2 in the direction perpendicular to the axial center of the piston 11.
It is set to have a relationship of St -82J, and Patsukin 1
The suction pressure and the discharge pressure applied to the end of the piston are made equal to each other.

Note that 32 is a suction groove, and 33 is a discharge pipe for discharging discharge gas from inside the sealed case 2 to the refrigeration cycle circuit.

Thus, in such a compressor, when the rotor 6 rotates due to energization of the electric motor section 3, the cylinder 7 also rotates together with the rotor 6. Along with this, the piston 11
rotates around the central axis B of the cylinder 7, with a part of its outer circumferential surface contacting the inner circumferential surface of the cylinder 7.

Note that such relative rotational movement between the piston 11 and the cylinder 7 is ensured by the Oldham ring 15.

On the other hand, the blade 17 rotating together with the piston 11 rotates with its outer circumferential surface in line contact with the inner circumferential surface of the cylinder 7. Then, each part of the blade 17 is connected to the piston 11.
As it approaches the contact area between the outer peripheral surface of the cylinder 7 and the inner peripheral surface of the cylinder 7, it is pushed into the groove part 16, and as it moves away from the contact part, it comes out of the groove part 16. As a result, the medium gas is sucked into the cylinder 7 through the suction pipe 22 and the suction hole 21. And this refrigerant gas is space 2
3, it is sequentially transferred to the compression chamber 18 on the discharge side whose volume decreases as the piston 11 rotates while remaining confined in the crescent-shaped compression chamber 18. As a result, the refrigerant gas is compressed. Then, this compressed refrigerant gas passes through the discharge hole 27, the inside of the sealed case 2, and the discharge pipe 33, and is discharged into the refrigeration cycle circuit.

During this compression process, the lubricating oil 31 is constantly pressed by the discharge pressure discharged into the sealed case 2, and
The oil is introduced into the inner bottom of the groove 16 through the oil introduction path 28. The blade 17 is constantly pressed toward the inner peripheral surface of the cylinder 7 by the lubricating oil 31 introduced between the groove 16 and the blade 17, thereby preventing gas leakage from the compression chamber 18.

During this compression operation, a part of the suction gas in the space 23 is introduced into the pressure sealed chamber 20b on the discharge side through the gas inlet 24, the passage 25, and the gas outlet 26. At the same time, a portion of the lubricating oil 31 passing through the through hole 29 and the introduction pipe 30 is introduced into the pressure sealed chamber 20a on the suction side, eliminating the differential pressure that causes the thrust force of the piston 11. It will be done.

In detail, if we look at the pressure applied to the end of the piston 11,
On the suction side, suction pressure is applied to the end surface of the piston outside the seal with the seal 19 as a boundary. However, a discharge pressure opposite to the suction pressure is applied to the inside of the packing by the pressure sealed chamber 20g.

Further, on the discharge side, discharge pressure is applied to the piston end face outside the seal with the seal 19 as a boundary. However, a suction pressure opposite to the discharge pressure is applied to the inside of the packing by the pressure sealed chamber 20b.

However, at both ends of the piston 11, the differential pressure between the suction pressure on the suction side and the discharge pressure on the discharge side, which causes the generation of thrust force, is canceled by the fluid pressure acting in the opposite direction to the thrust direction. Here, both forces are r2s,
Since they are set equally in the relationship of -52J, the thrust force is almost completely canceled out in balance. In other words, the piston 11 is released from the thrust force.

Therefore, the piston 11 can be rotated smoothly, and the compressor 1 can operate smoothly.

In addition, in the above embodiment, the passage 25 provided in the piston 11
The fluid pressure can be introduced into the pressure sealed chamber 20a using is introduced into the pressure sealed chamber 20b, but the present invention is not limited to this structure, and other introduction structures may be used to guide the required fluid pressure into the pressure sealed chambers 20a, 20b by rotating the piston around the cylinder. Although the present invention has been applied to a helical blade type compressor, it goes without saying that it can also be applied to a helical blade type compressor in which the piston is rotated about the axis of the piston.

[Effects of the Invention] As described above, according to the present invention, it is possible to eliminate the differential pressure that causes the generation of thrust force and balance the forces at both ends of the piston.

Therefore, the piston can be released from the thrust force, and the piston can be rotated smoothly.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a sectional view showing a helical blade type compressor, and FIG.
It is a sectional view taken along the line XX in the figure. 4... Compressor section, 7... Cylinder 8, 9...
Bearing (supporting member), 11... Piston, 12a, 12
b... Support shaft portion, 10... Oldham mechanism, 16...
Spiral groove, 17...blade, 18...compression chamber, 20a. 20b...Pressure sealed chamber, 21...Suction hole, 24...
・Gas inlet, 25... Passage, 26... Gas outlet, 27... Discharge hole, 28... Oil inlet, 29...
Through hole, 30...Introduction pipe, 31...Lubricating oil.

Claims (1)

[Claims] A cylindrical cylinder with one end on the suction side and the other end on the discharge side, and a cylindrical piston inserted into the cylinder eccentrically so that a part of the outer circumferential surface touches the inner circumferential surface of the cylinder. , a spiral groove formed on the outer peripheral surface of the piston with a pitch that decreases from the suction side to the discharge side; an inserted helical blade; a support member that supports the ends of the piston and the cylinder so as to be rotatable about the axis on one side; and a support member that supports the ends of the piston and the cylinder so as to be rotatable relative to the other; In the compressor, the compressor has a means for rotating the piston and rotating the rotation support side relative to the piston in accordance with the rotation, the end face of the piston facing the end surface of the piston. A pressure sealed chamber is formed between the supported part of the supporting member and a means for guiding an opposite fluid pressure from the compressor section to the pressure sealed chamber to resist the force in the thrust direction generated in the piston. A compressor characterized by the following: