JPH05231309A - Structure for lubrication in piston type compressor - Google Patents

Abstract

PURPOSE:To improve lubricating performance and volumetric efficiency of a piston driving mechanism by leading a gas purging passage up to a connecting portion between a rotary shaft and a rotary valve which supplies refrigerant gas to a compression chamber, and also by forming an inlet of the gas purging passage in a housing chamber of the piston driving mechanism. CONSTITUTION:In a rocking swash plate type compressor, rotary motion of a rotary shaft 4 is converted to reciprocating rock motion of a rocking swash plate 9 through a rotary holder 5 and a rotary driver 6. Thus, pistons 10A move backwards and forwards in cylinder bores 1a. Refrigerant gas and lubricating oil are introduced into a crank case 2a in which driving mechanisms 5, 6 and 9 are contained. In this case, a rotary valve 14 is contained in respective containing parts 1b and 3b of a cylinder block 1 and a rear housing 3. In addition, a suction passage 17 is formed in the rotary valve 14, and is connected to a compression chamber P. Furthermore, gas purging passages 18 (A, B) are formed in the rotary shaft 4 and elongated up to the part connected to the rotary valve 14, and also an inlet 18a of the gas purging passage 18 is formed in the crank case 2a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crank chamber in which a piston is housed in a plurality of cylinder bores arranged around a rotary shaft and a drive mechanism for converting the rotation of the rotary shaft into a reciprocating linear motion of the piston. With introducing refrigerant gas into
The present invention relates to a lubricating structure in a piston type compressor provided with a gas vent passage for venting the refrigerant gas from the crank chamber by introducing lubricating oil into the crank chamber by the action of refrigerant gas inflow.

[0002]

2. Description of the Related Art In a conventional piston type compressor, a suction port between a compression chamber and a suction chamber defined by a piston in a cylinder bore is opened and closed by a flapper valve in the compression chamber. The refrigerant gas in the suction chamber pushes the flapper valve open by the suction operation of the piston moving from the top dead center side to the bottom dead center side and flows into the compression chamber. In the discharge stroke in which the piston moves from the bottom dead center side to the top dead center side, the flapper valve closes the suction port, and the refrigerant gas in the compression chamber is discharged from the discharge port to the discharge chamber.

The opening / closing operation of the flapper valve is based on the pressure difference between the compression chamber and the suction chamber, and if the pressure in the suction chamber is higher than the pressure in the compression chamber, the flapper valve flexes and deforms to open the suction port. .. The pressure in the suction chamber becomes higher than the pressure in the compression chamber during the suction stroke in which the piston moves from the top dead center side to the bottom dead center side.

The rocking swash plate type compressor disclosed in JP-A-61-255285 and JP-A-61-268877 is a kind of piston type compressor. A mechanism for reciprocating a piston housed in the cylinder bore is housed in a crank chamber in the front housing. This drive mechanism consists of a lug plate, sleeve, and
The drive plate is supported on the sleeve, and the swing swash plate is supported on the drive plate so as to be relatively rotatable. The drive plate is connected to the lug plate with the engagement relationship between the guide pin and the long hole, and rotates in the same direction as the rotation shaft rotates. The rotation of the drive plate causes the swash plate to oscillate back and forth, causing the piston to reciprocate linearly in the cylinder bore.

In this conventional rocking swash plate compressor, the discharged refrigerant gas is introduced into the crank chamber and the refrigerant gas in the crank chamber is discharged so as to have a constant pressure. The stroke amount of the piston is determined based on the differential pressure between the constant pressure in the crank chamber and the suction pressure in the cylinder bore,
The compression capacity changes according to the fluctuation of the suction pressure that reflects the cooling load.

[0006]

The flexural deformation of the flapper valve used in such a piston type compressor acts as an elastic resistance and does not open unless the pressure in the suction chamber exceeds the pressure in the compression chamber to some extent. That is, opening of the flapper valve is delayed. Lubricating oil is mixed in the refrigerant gas in order to lubricate the inside of the compressor, and this lubricating oil is sent together with the refrigerant gas to a necessary lubrication site in the compressor. This lubricating oil can enter anywhere in the circulation region of the refrigerant gas, and the lubricating oil also adheres between the flapper valve that closes the suction port and its close surface. The attached lubricating oil enhances the adhesion between the close contact surface and the flapper valve, and the start of the flexural deformation of the flapper valve is further delayed. Such a delay in the start of deformation causes a decrease in the amount of refrigerant gas flowing into the compression chamber, that is, a decrease in volumetric efficiency. Further, even when the flapper valve is open, the elastic resistance of the flapper valve acts as suction resistance, and the refrigerant gas inflow amount decreases.

Further, the refrigerant gas flowing into the suction chamber from the external refrigerant circuit expands due to the heat generated by the compressor itself, and the density of the refrigerant gas in the suction chamber decreases. Usually, the suction chamber is adjacent to the discharge chamber, and the refrigerant gas in the suction chamber expands due to the heat of the discharge chamber, which is the region where the high temperature gas exists. The decrease in density of the refrigerant gas before flowing into the compression chamber leads to a substantial decrease in compression capacity in the compression chamber, that is, a decrease in volumetric efficiency.

In the conventional rocking swash plate type compressor using the flapper valve as the intake valve, there is a problem related to lubrication of the drive mechanism in the crank chamber in addition to the problem of volume efficiency. That is, in order to keep the pressure in the crank chamber at a constant pressure, the refrigerant gas in the crank chamber is extracted into the suction pressure region, but with this degassing, the lubricating oil in the crank chamber is taken out, and the amount of lubricating oil in the crank chamber is increased. May run short.

In the rocking swash plate type compressor disclosed in JP-A-61-255285 and JP-A-61-268877, a passage for removing gas from the crank chamber is formed in the rotary shaft. , Its inlet opens into the crank chamber. With such a gas vent passage structure, the oil in the refrigerant gas flowing in the gas vent passage in the rotary shaft is separated by centrifugal action. Therefore, the drive mechanism in the crank chamber is well lubricated.

An object of the present invention is to provide a piston type compressor which improves volumetric efficiency while utilizing such a gas vent passage.

[0011]

Therefore, according to the present invention,
An intake passage for introducing the refrigerant gas into the compression chamber defined by the piston in the cylinder bore is formed on the rotary valve so that the compression chamber and the intake passage are sequentially communicated with each other in synchronization with the reciprocating movement of the piston. The rotary valve is provided, and a degassing passage is introduced through the inside of the rotary shaft to a connecting portion between the rotary shaft and the rotary valve, and in a crank chamber in which a drive mechanism for converting the rotation of the rotary shaft into a reciprocating linear motion of the piston is housed. An inlet for the gas vent passage was provided.

[0012]

The suction passage on the rotary valve sequentially communicates with the plurality of compression chambers as the rotary valve rotates. When the suction passage and the compression chamber communicate with each other, the piston moves toward the bottom dead center side, and the pressure in the compression chamber decreases to the pressure in the suction passage (suction pressure) or less. Due to this pressure decrease, the refrigerant gas in the suction passage flows into the compression chamber. Unlike the flapper valve,
The suction passage communicates with the compression chamber at a predetermined timing.

Refrigerant gas in the crank chamber enters the degassing passage in the rotary shaft and escapes to the suction pressure region. The lubricating oil that has entered the gas vent passage together with the refrigerant gas is returned to the crank chamber from the inlet of the gas vent passage by the centrifugal action. The remaining lubricating oil is guided to the connecting portion between the rotary valve and the rotary shaft together with the refrigerant gas. By providing a passage from this connection portion to the inner peripheral surface of the rotary valve accommodating chamber, the lubricating oil in the refrigerant gas is efficiently supplied to the peripheral surface of the rotary valve accommodating chamber by the centrifugal action. The supplied lubricating oil enhances the sealing property between the peripheral surface of the rotary valve and the peripheral surface of the housing chamber, and prevents leakage of high-pressure refrigerant gas in the compression chamber.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a variable displacement type swash plate compressor will be described below with reference to FIGS.

A front housing 2 and a rear housing 3 in which a crank chamber 2a is formed are joined and fixed to the front and rear of the cylinder block 1, and a rotary shaft 4 rotatably supported by the cylinder block 1 and the front housing 2.
The rotary support 5 is fixed to the. A rotation driving body 6 is connected to and supported by the rotation support body 5 by engaging a long hole 5b on the arm 5a and a pin 7 with a variable tilt angle. The rotary drive body 6 is swingably supported by shaft pins 8a projecting from the left and right sides of a guide sleeve 8 on the rotary shaft 4, and a swing swash plate 9 is relatively rotatable on the rotary drive body 6. It is supported. A drive mechanism including the rotary support 5, the rotary drive 6, the swing swash plate 9 and the like is housed in the crank chamber 2a.

The cylinder block 1 has a plurality of cylinder cylinders.
A 1a (six in this embodiment) is provided in the axial direction of the rotary shaft 4.
Are arranged at equal angular positions around the rotation axis 4.
Has been. A piston 10A is provided in the cylinder bore 1a.₁，
10A₂, 10A₃, 10A _Four, 10A_Five, 10A₆But
It is housed. Each piston 10A_j(J = 1 to 6) is
Is connected to the swing swash plate 9 via the piston rod 10a.
There is. The rotary motion of the rotary shaft 4 is driven by the rotary support 5 and the rotary drive.
The swing swash plate 9 is converted into forward and backward reciprocating swing through the body 6, and
Stone 10A_jMoves back and forth in the cylinder bore 1a.

A valve plate 11, a valve forming plate 12 and a retainer forming plate 13 are sandwiched between the cylinder block 1 and the rear housing 3, and a discharge chamber 3a is formed in the rear housing 3. Piston 1
0A compression chamber is defined in each cylinder bore 1a by _{j P 1, P 2, P} 3, P 4, P 5, P 6 is partitioned from the discharge chamber 3a by a valve plate 11, the discharge port on the valve plate 11 11a is formed so as to communicate with the compression chamber P _j . A flapper valve type discharge valve 12a is formed on the valve forming plate 12, and a retainer 13a is formed on the retainer forming plate 13. The discharge valve 12a opens and closes the discharge port 11a on the discharge chamber 3a side, and the retainer 13a regulates the amount of bending deformation of the discharge valve 12a.

Cylinder block 1 and rear housing 3
Housing recesses 1b and 3b are formed in the center of the facing end faces of the rotary shaft 4, and the end of the rotary shaft 4 projects into the housing recess 1b. Both of the accommodating recesses 1b and 3b form a cylindrical accommodating chamber having an axis in the axial direction of the rotary shaft 4, and the rotary valve 14 is rotatably accommodated in the accommodating recesses 1b and 3b.
A thrust bearing 15 is interposed between the end surface of the housing recess 3b and the end surface of the rotary valve 14, and a coupling 16 is fitted and fixed to the end surface of the rotary valve 14 on the housing recess 1b side. The projecting end 4a of the rotary shaft 4 projecting into the accommodation recess 1b and the coupling 16 are fitted together such that they cannot rotate relative to each other.
It rotates integrally in the accommodating chambers 1b and 3b in the direction of arrow R in FIG. Thrust bearing 15 is rotary valve 14
It receives the thrust load against.

A suction passage 17 is formed in the rotary valve 14 so as to extend from the end surface on the accommodation recess 3b side to the peripheral surface of the rotary valve 14. An inlet 3c is formed in the center of the rear housing 3 so as to connect to the accommodation recess 3b, and an inlet 17a of the suction passage 17 communicates with the inlet 3c.

Compression chambers P _{1 to} P ₆ are provided on the peripheral surface of the accommodation recess 1b.
The same number of suction ports 1c ₁ , 1c ₂ , 1c ₃ , 1c ₄ ,
1c ₅ and 1c ₆ are arrayed at equal angular positions. The suction port 1c _j and the compression chamber P _j (j = 1 to 6) are always in one-to-one communication, and each suction port 1c _{j in} the suction process is connected to the circulation region of the outlet 17b of the suction passage 17. ing. In the state shown in FIGS. 1 and 2, the piston 10A
₁ is at the top dead center position, and the piston 10A ₄ at the 180 ° rotationally symmetrical position is at the bottom dead center position. In such a piston arrangement state, the outlet 17b is connected to the suction port 1c ₁ ,
It is arranged between the two without connecting to 1c ₄ . That is,
When the piston 10A ₁ enters the suction stroke from the top dead center position to the bottom dead center position, the suction passage 17 communicates with the compression chamber P ₁ , and the refrigerant gas supplied from the introduction port 3c receives the suction passage in the rotary valve 14. It is sucked into the compression chamber P ₁ via 17. On the other hand, when the piston 10A ₄ enters the discharge stroke from the bottom dead center position to the top dead center position, the suction passage 1
7 is cut off from communication with the compression chamber P ₄ . Such refrigerant gas suction is similarly performed in the other compression chambers P _{1 to} P ₃ , P ₅ , and P ₆ .

The refrigerant gas sucked into the compression chamber P _j is discharged to the discharge chamber 3a while being compressed by the discharge operation of the piston from the bottom dead center position to the top dead center position. The stroke of the piston changes according to the pressure difference between the suction pressure in the compression chamber P _j and
The tilt angle of the swing swash plate 9 that affects the compression capacity changes. The pressure in the crank chamber 2a is controlled by supplying the refrigerant gas in the discharge pressure region to the crank chamber 2a and controlling the discharge of the refrigerant gas in the crank chamber 2a to the suction pressure region by a control valve mechanism (not shown).

In the rotary shaft 4, gas vent passages 18A, 18
B extends from the peripheral surface of the rotating shaft 4 to the end surface of the protruding end portion 4a. The gas vent passage 18A is orthogonal to the rotation axis of the rotary shaft 4, and the gas vent passage 18B is provided on the rotation axis. An inlet 18a of the gas vent passage 18A opens into the crank chamber 2a.

A space S ₁ is secured between the end surface of the protruding end 4a of the rotary shaft 4 and the coupling 16, and the outlet 18b of the gas vent passage 18B opens into the space S ₁ .
The projecting end 4a and the coupling 16 are fitted in a square shape, and one of the fitting corners of the projecting end 4a has a passage forming surface 4a.
₁ is chamfered. That is, a passage is formed between the inner surface of the coupling 16 and the passage forming surface 4a ₁ .
The coupling 16 passing port 16a is formed notches in correspondence with the passage formation surface 4a _1, passing opening 16a and the gap S
It communicates with ₁ .

The bottom of the accommodating recess 1b and the rotary valve 14
A gap S ₂ is secured between the end face of the
a is connected to the void S ₂ . A gas vent passage 19 is formed in the cylinder block 1 and the rear housing 3. One end of the gas vent passage 19 is connected to the space S ₂ , and the other end is connected to a control valve (not shown). Therefore,
The crank chamber 2a has a gas vent passage 18, a gap S ₁ , and a passage 1
6a, the space S ₂ , and the gas vent passage 19 communicate with the control valve.

The crank chamber 2a communicates with the discharge chamber 3a via a gas introduction passage (not shown), and the high-pressure refrigerant gas in the discharge chamber 3a passes through the gas introduction passage to the crank chamber 2a.
Flows in. The refrigerant gas in the crank chamber 2a reaches the control valve through the gas vent passage 18, the gap S ₁ , the passage 16a, the gap S ₂ , and the gas vent passage 19, and the control valve controls the pressure in the crank chamber 2a. The degassing amount in the crank chamber 2a is controlled so that the pressure is constant.

In the case of the flapper valve type suction valve, the lubricating oil increases the suction force between the suction valve and its contact surface, and the suction valve delays the opening start timing of the suction valve. This delay, the suction resistance due to the elastic resistance of the suction valve, and the thermal expansion of the refrigerant gas in the suction chamber reduce the volumetric efficiency. However, the rotary valve 14 that is forcedly rotated
In this case, there is no problem of the suction force due to the lubricating oil and the suction resistance due to the elastic resistance of the suction valve, and if the pressure inside the compression chamber P _j is slightly lower than the suction pressure, the refrigerant gas immediately flows into the compression chamber P _j . Further, since the refrigerant gas flowing from the external refrigerant circuit into the compression chamber P _j passes through the path of the suction passage 17 in the rotary valve 14 relatively separated from the discharge chamber 3a, the thermal expansion of the refrigerant gas is also suppressed. Therefore, the rotary valve 1
In the case of adopting No. 4, the volume efficiency is significantly improved compared to the case of adopting the flapper valve type intake valve.

The lubricating oil mixed in the refrigerant gas in the crank chamber 2a enters the gas vent passage 18 together with the refrigerant gas flow flowing from the inlet 18a of the gas vent passage 18. Part of the lubricating oil that has entered the gas vent passage 18 is separated from the refrigerant gas by the centrifugal action in the rotating gas vent passage 18A, and is returned to the crank chamber 2a from the inlet 18a. Therefore, the retention efficiency of the lubricating oil in the crank chamber 2a is good, and the rotation support body 5, the rotation drive body 6, the guide sleeve 8,
The necessary lubrication portion of the piston drive mechanism including the swing swash plate 9 and the like is satisfactorily lubricated.

The lubricating oil that has entered the gas vent passage 18B together with the refrigerant gas reaches the space S ₁ . The passage cross-sectional area in the void S ₁ is considerably larger than the passage cross-sectional area in the degassing passage 18B, and the flow velocity of the refrigerant gas flow from the degassing passage 18B to the void S ₁ decreases. The lubricating oil in the refrigerant gas is separated due to the decrease in the flow velocity and adheres to the peripheral surface of the void S ₁ . The lubricating oil separated in the space S ₁ flows out into the space S ₂ through the passage 16a together with the refrigerant gas flow.
In addition, the lubricating oil in the refrigerant gas in the passage 16a is also separated by the centrifugal action. Since the coupling 16 also rotates integrally with the rotary shaft 4, the lubricating oil separated in the space S ₁ and in the through hole 16a adheres to the peripheral surface of the housing recess 1b by centrifugal action. The lubricating oil attached to the peripheral surface of the housing recess 1b enters the clearance between the peripheral surface of the rotary valve 14 and the peripheral surface of the housing recess 1b. The lubricating oil that has entered the clearance between the peripheral surface of the housing recess 1b and the peripheral surface of the rotary valve 14 plays a role of preventing leakage of the compressed refrigerant gas in the compression chamber P _j . That is, the refrigerant gas in the compression chamber P _j in the compressed state is a low pressure region due to the high pressure, and the accommodation recess 1b,
Easy to leak to 3b. The refrigerant gas that has leaked to the accommodation recess 1b is returned to the suction passage 17 again. Such refrigerant gas recirculation reduces the amount of refrigerant gas flowing into the compressor from the external refrigerant circuit, leading to a reduction in volumetric efficiency.

Refrigerant gas leakage along the peripheral surface of the rotary valve 14 is prevented by the lubricating oil efficiently separated and adhered to the peripheral surface of the accommodation recess 1b by the centrifugal action, and the volumetric efficiency is prevented from decreasing due to the refrigerant gas leakage. ..

That is, the gas vent passage 18A is connected to the crank chamber 2
The lubrication of the piston drive mechanism is enhanced by suppressing the outflow of the lubricating oil in a, and the lubricating oil that has flowed out from the crank chamber 2a is prevented from gas leakage between the rotary valve 14 and the housing recesses 1b and 3b by the centrifugal separation action. Be offered to.

The present invention is of course not limited to the above-mentioned embodiment, and an embodiment in which a cylindrical coupling 20 is used as shown in FIG. 4 to increase the volume of the space S ₁ is also possible. .. Flow rate decrease of the refrigerant gas flowing out from the gas vent passage 18B into the gap S ₁ is increased by promoting the volume expansion of the gap S _1, a lubricating oil separation is better.

Further, as shown in FIGS. 5 and 6, the refrigerant gas extracted from the crank chamber 2a via the gas vent passages 18A and 18B is supplied to the gas vent passage 2 in the rotary valve 14.
An embodiment in which it is taken out to the suction passage 17 via 1 is also possible. A fixed throttle 21a is formed on the gas vent passage 21, and a gas supply passage 22 is formed on the cylinder block 1 and the rear housing 3. One end of the gas supply passage 22 communicates with the crank chamber 2a, and the other end communicates with a control valve (not shown). This control valve is used in the crank chamber 2a
The amount of refrigerant gas supplied to the crank chamber 2a is controlled so that the internal pressure is kept constant. Therefore, degassing from the crank chamber 2a needs to be throttled by the fixed throttle 21a.

In the case of the embodiment of FIG. 5, the coupling 16
The Tsuguchi 16b Yes and is formed, enters into centrifuged lubricant accommodating recess 1b in through the through hole 16b in the gap S _1. In the embodiment shown in FIG. 6, a space S ₃ is secured between the end face of the coupling 16 and the rotary valve 14, and the fixed orifice 21a is directly connected to the space S ₃ . Further, the formation circumferential surface of the space S ₃ are lubricating passageway 14a is formed, lubricating oil separated in the gap S ₃ is reached from the lubricating passage 14a by centrifugal action on the peripheral surface of the rotary valve 14.

Further, in the present invention, as shown in FIG. 7, the inlet 23a of the gas vent passage 23 may be provided on the rotary support 6. If the inlet 23a is far away from the center of rotation of the rotary shaft 4, the lubricating oil separating action will be further improved.

[0035]

As described above in detail, according to the present invention, the gas vent passage is guided to the connection point between the rotary valve for supplying the refrigerant gas to the compression chamber and the rotary shaft, and the gas vent is introduced into the accommodating chamber of the piston drive mechanism. Since the entrance of the passage was set up,
This has the excellent effect that the piston drive mechanism can be satisfactorily lubricated and the volume efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a side sectional view of an entire compressor showing an embodiment embodying the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a side sectional view showing another example.

FIG. 5 is a side sectional view showing another example.

FIG. 6 is a side sectional view showing another example.

FIG. 7 is a side sectional view showing another example.

[Explanation of symbols]

1a ... Cylinder bore, 2a ... Crank chamber accommodating the piston drive mechanism, 4 ... Rotating shaft, 10A ₁ , 10A ₂ , 10
A ₃ , 10A ₄ , 10A ₅ , 10A ₆ ... Piston, 14
... Rotary valve, 17 ... Suction passage, 18A, 18B ...
Degassing passage, 18a ... inlet, P ₁ , P ₂ , P ₃ ,
_{P 4, P 5, P 6} ... the compression chamber.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideki Mizutani, 2-chome, Toyota-cho, Kariya city, Aichi Prefecture Toyota Industries Corporation

Claims (1)

[Claims] 1. A refrigerant gas is introduced into a crank chamber in which a piston is housed in a plurality of cylinder bores arranged around a rotary shaft, and a drive mechanism for converting the rotation of the rotary shaft into a reciprocating linear motion of the piston. Along with the introduction of the lubricating gas into the crank chamber by the inflow action of the refrigerant gas, in a piston type compressor provided with a gas vent passage for venting the refrigerant gas in the crank chamber, the refrigerant enters the compression chamber defined by the piston in the cylinder bore. An intake passage for introducing gas is formed on the rotary valve, and the rotary valve is provided so as to sequentially connect the compression chamber and the intake passage in synchronism with the reciprocating movement of the piston. A piston-type pressure that guides the gas vent passage to the connection point between the rotary shaft and the rotary valve and that has an inlet for the gas vent passage in the crank chamber. Lubrication structure in the compressor.