JP3666170B2 - Swash plate compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a swash plate type compressor, and is effective as a compressor for a refrigeration cycle applied to a refrigeration cycle having a high discharge pressure using carbon dioxide (CO ₂ ) or the like as a refrigerant.
[0002]
[Prior art]
In recent years, research on a refrigeration cycle using carbon dioxide (CO ₂ ) as a refrigerant (hereinafter referred to as a CO ₂ cycle) has been actively conducted as a countermeasure against de-Freon of an air conditioner (refrigeration cycle). Since this CO ₂ cycle has a higher discharge pressure of the compressor than a normal refrigeration cycle (hereinafter abbreviated as refrigeration cycle) using chlorofluorocarbon as a refrigerant, the compressor used in the refrigeration cycle should be used as it is. I can't.
[0003]
By the way, in the swash plate type compressor, the swing plate (swash plate) and the piston can swing by sliding while the spherical sliding surface formed at the tip of the piston and the shoe are in contact with each other. A compression reaction force is concentrated on the shoe and the sliding surface. For this reason, when a high discharge pressure is required as in the CO ₂ cycle, it is particularly necessary to sufficiently lubricate the sliding surface and the shoe.
[0004]
Incidentally, the discharge pressure in the case of Freon is about 1.6 MPa, and the discharge pressure in the case of CO ₂ is about 12 MPa that exceeds the critical pressure (7.4 MPa) of CO ₂ .
In order to satisfy the above-described need, a hydraulic pump or the like that sucks and compresses an incompressible fluid slides from the working chamber (compression chamber) side as described in, for example, Japanese Patent Laid-Open No. 5-113173. A communication passage that penetrates in the longitudinal direction of the piston to the surface is provided, and means for guiding the working oil sucked into the working chamber to the sliding surface is adopted.
[0005]
[Problems to be solved by the invention]
However, when the means described in the above publication is applied to a swash plate compressor that sucks and compresses a compressible fluid as in a CO ₂ cycle, the following problems occur.
That is, in the means described in the above publication, since the communication path a is formed in the piston 6 as shown in FIG. 10, even if the piston 6 reaches the top dead center, the swing plate 10 and the shoe 8 The hydraulic fluid leaking into the swash plate chamber through the gap between the discharge flow rate and the volume of the communication passages a, b, c decreases.
[0006]
By the way, since the discharge flow rate to be reduced is small in terms of volume flow rate, in the case of sucking and compressing an incompressible fluid like a hydraulic pump, a decrease in efficiency due to the reduced discharge flow rate can be almost ignored.
However, since the compressor applied to the refrigeration cycle included in the CO ₂ cycle sucks and compresses a compressive fluid such as chlorofluorocarbon or CO ₂ as a refrigerant, the refrigerant density at the time of discharge is high, and the discharge flow rate that decreases is volume Even if it is small in flow rate conversion, it becomes large when converted into mass flow rate. Therefore, when the means described in the above publication is applied to a compressor for a refrigeration cycle (included in a CO ₂ cycle), there arises a problem that the efficiency of the compressor is greatly reduced.
[0007]
An object of the present invention is to supply lubricating oil to a shoe and a sliding surface in a swash plate type compressor that sucks and compresses a compressive fluid while suppressing a decrease in efficiency of the compressor. To do.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention uses the following technical means. In the invention according to any one of claims 1 to 7 , in the swash plate type compressor for sucking and compressing the compressive fluid, the cylinder port (51) which opens to the inner wall (5a) of the cylinder bore (5) and into which the lubricating oil is guided, A piston port (63) opening in the side wall (6b) of the piston (6), and a communication path (64, 65) communicating from the piston port (63) through the inside of the piston (6) to the sliding surface (6a) It is characterized by providing.
[0009]
Thereby, the lubricating oil slides from the cylinder port (51) formed on the inner wall (5a) of the cylinder bore (5) via the piston port (63) formed on the side wall (6b) of the piston (6). Since it is guided to the surface (6a), it is prevented from decreasing the discharge flow rate of the compressive fluid discharged from the swash plate compressor, unlike the case where the lubricating oil is supplied from the working chamber side as described in the above publication. be able to. Accordingly, it is possible to supply the lubricating oil to the shoe (8) and the sliding surface (6a) while suppressing a decrease in the efficiency of the swash plate compressor.
[0011]
By the way, the force (F1) acting on the contact surface between the sliding surface (6a) and the shoe (8) is maximized when the compression reaction force acting on the piston (6) is maximized. In the invention described in claim 1 , when the compression reaction force acting on the piston (6) becomes maximum, the cylinder port (51) and the piston port (63) It is characterized by being formed so that the opening surface faces.
[0012]
Therefore, in the first aspect of the invention, the contact surface between the sliding surface (6a) and the shoe (8) can be efficiently lubricated. Further, as in the invention according to claim 2, the lubricating oil is directly led to the cylinder port from the tank means (140) for separating the gas-phase refrigerant and the liquid-phase refrigerant provided in the refrigeration cycle. Can be. Further, in the swash plate type compressor according to 請 Motomeko 2, as in the invention of claim 3, lubricating oil is guided directly to the cylinder port via an external pipe (150,25) (51) Can be. Further, in the swash plate compressor according to claim 2, as in the invention according to claim 4 , the tank means is disposed between the radiator (110) and the evaporator (130) in the refrigeration cycle. It may be a receiver that has been changed. In addition, as described in claim 5 , a cylinder groove for guiding lubricating oil over the entire circumference of the inner wall (5a) to a portion of the inner wall (5a) of the cylinder bore (5) corresponding to the cylinder port (51). 51a) may be formed. In addition, as described in claim 6 , the piston groove that guides the lubricating oil to the portion corresponding to the piston port (63) in the side wall (6b) of the piston (6) over the entire outer wall of the side wall (6b). (61a) may be formed. The invention according to claim 7 is characterized in that the swash plate type compressor according to any one of claims 1 to 6 is used as a compressor for compressing to a critical pressure or higher of the compressive fluid.
[0013]
In addition, the code | symbol in the bracket | parenthesis of each said means shows a corresponding relationship with the specific means of embodiment description later mentioned.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention shown in the drawings will be described.
(First embodiment)
This embodiment shows a case where the present invention is applied to a compressor of a vapor compression refrigeration cycle (CO ₂ cycle) using CO ₂ as a refrigerant. FIG. 1 shows a swash plate compressor (hereinafter simply referred to as compression) according to the present invention. This is a CO ₂ cycle using a vehicle air conditioner.
[0015]
In FIG. 1, reference numeral 100 denotes a compressor driven by obtaining driving force from a vehicle running engine (not shown), and compresses CO ₂ in a gas phase state. Reference numeral 110 denotes a radiator (gas cooler) that cools CO ₂ compressed by the compressor 100 by exchanging heat with the outside air or the like, and 120 radiates heat according to the CO ₂ temperature on the outlet side of the radiator 110. It is a pressure control valve that controls the outlet side pressure of the vessel 110. The pressure control valve 120 controls the outlet side pressure of the radiator 110 and also serves as a decompressor. The CO ₂ is decompressed by the pressure control valve 120 and is a low-temperature low-pressure gas-liquid two-phase CO 2. ₂
[0016]
130 is an evaporator (heat absorber) that serves as an air cooling means in the passenger compartment, and CO ₂ in a gas-liquid two-phase state takes away latent heat of evaporation from the passenger compartment air when it is vaporized (evaporates) in the evaporator 130. Cool the passenger compartment air. 140 is configured to separate the CO ₂ in the CO ₂ and the liquid-phase state of gas phase is accumulator (tank unit) for storing CO ₂ in the gas phase state temporarily.
[0017]
FIG. 2 shows a cross section in the axial direction of the compressor 100. Reference numeral 1 denotes a shaft that rotates by obtaining a driving force from an external driving source (such as a vehicle traveling engine) via an electromagnetic clutch (not shown). The shaft 1 is rotatably held by a radial bearing 101 disposed in the front housing 2 and the cylinder block 3. Here, the radial bearing 101 opposes the load in the vertical direction of the shaft 1.
[0018]
Further, in a space (hereinafter referred to as a swash plate chamber) 2 a formed by the front housing 2 and the cylinder block 3 in the shaft 1, an inclined surface 4 a inclined with a predetermined angle with respect to the shaft 1 is provided. The formed swash plate 4 is press-fitted into the shaft 1, whereby the shaft 1 and the swash plate 4 rotate together. Further, a surface 4b perpendicular to the shaft 1 is formed on the swash plate 4 on the side opposite to the inclined surface 4a. A thrust bearing 102 is disposed between the surface 4b and the front housing 2. It opposes the compression reaction force acting on the swash plate 4.
[0019]
Further, in the cylinder block 3, a cylinder bore 5 that penetrates the cylinder block 3 in the axial direction of the shaft 1 at a position that is parallel to the shaft 1 and is equally divided into six in the circumferential direction around the shaft 1 (see FIG. 3). Are formed, and pistons 6 that reciprocate in the axial direction of the shaft 1 while being in contact with the inner walls of the respective cylinder bores 5 are inserted into the respective cylinder bores 5.
[0020]
Between the piston 6 and the swash plate 4, a swing member 7 that swings in the axial direction of the shaft 1 about the shaft 1 is disposed. It is slidably connected to the piston 6 via a brass shoe 8 slidably connected to a spherical sliding surface 6a formed at the end. The shoe 8 is in contact with a retainer 9 that is a holding member for the shoe 8 and a rolling element 103 a of a thrust bearing 103 disposed on the swash plate 4, and a swing plate 10 that is rotatably connected to the swash plate 4. And is held so as to be slidable with respect to the swing plate 10.
[0021]
Incidentally, the rocking plate 10 also serves as a bearing race for the thrust bearing 103, and this thrust bearing 103 opposes the compression reaction force acting on the rocking member 7 via the piston 6.
A spacer 11 is disposed between the retainer 9 and the shaft 1 so as to be rotatable in contact with the retainer 9, and the contact surface between the spacer 11 and the retainer 9 changes the inclination angle of the swash plate 4. The swash plate 4 side is formed in a substantially spherical shape with a convex shape. Reference numeral 12 denotes a spring that generates an elastic force that presses the spacer 11 toward the swash plate 4, and a gap 11 a is formed between the spacer 11 and the shaft 1. The gap 11a prevents the frictional resistance between the spacer 11 and the shaft 1.
[0022]
Incidentally, a valve plate 13 is disposed at the end of the cylinder block 3 so as to face the piston 6 and close one end side of the cylinder bore 5, and the valve plate 13 includes a plurality of valves communicating with the cylinder bore 5. A suction port 14 and a discharge port 15 are formed.
Between the valve plate 13 and the rear housing 16, a suction chamber 17 that distributes refrigerant sucked from a suction port of a compressor (not shown) to each suction port 14 and refrigerant discharged from each discharge port 15. And a discharge chamber 18 that leads to a discharge port (not shown) of the compressor.
[0023]
A reed valve-like suction valve 19 is disposed on the piston 6 side of each suction port 14, and a reed-valve-like discharge valve 20 is similarly disposed on the discharge chamber 18 side of each discharge port 15. Has been. The maximum opening of the discharge valve 20 is regulated by a stopper 21, and both the valves 19 and 20 and the stopper 21 are sandwiched and fixed by the cylinder block 3 and the rear housing 16 together with the valve plate 13.
[0024]
Incidentally, 22 is a lip seal that prevents the refrigerant in the swash plate chamber 2a from leaking out of the compressor, and 23 is an O-ring made of nitrile rubber.
By the way, the piston 6 is composed of a cylindrical piston main body 61 and a connecting portion 62 in which a sliding surface 6a is formed. As shown in FIG. It is integrally formed from a steel material (SUJ-2).
[0025]
A piston port 63 is opened in a side wall 6 b facing the inner wall of the cylinder bore 5 in the piston main body 61 (piston 6). The piston port 63 is formed in the piston communication path 64 formed in the piston 6. , 65 to the sliding surface 6a.
In addition, a cylinder port 51 is opened in the inner wall 5a of each cylinder bore 5, and lubricating oil separated from CO ₂ in the accumulator 140 provided in the CO ₂ cycle is externally connected to the cylinder port 51. 150 (see FIG. 1).
[0026]
Incidentally, not only in the CO ₂ cycle but also in a refrigeration cycle using Freon, the lubricating oil and the refrigerant are usually mixed, and the lubricating oil circulates in the cycle together with the refrigerant. Therefore, CO ₂ surplus CO ₂ (coolant) is stored in the accumulator 140 is the density difference between them is separated into CO ₂ and lubricating oil.
A cylinder groove 51a is formed in the inner wall 5a of each cylinder bore 5 corresponding to each cylinder port 51 over the entire circumference of the inner wall 5a of the cylinder bore 5, and the lubrication guided to the cylinder port 51 by the cylinder groove 51a. Oil is circulated around the entire inner wall of the cylinder bore 5 (the entire periphery of the side wall of the piston 6).
[0027]
As shown in FIG. 3, each cylinder port 51 communicates with three cylinder communication paths 52 formed in the cylinder block 3, and the lubricating oil from the external pipe 150 is guided to the inlet 53. Yes. Incidentally, 53a, 53b is closed by a lid member after the cylinder communication passage 52 is formed.
Next, features of the present embodiment will be described.
[0028]
According to the present embodiment, as in the means described in the above publication, the communication passage penetrating from the working chamber (space formed by the cylinder bore and piston) side to the sliding surface 6a is provided to allow fluid in the working chamber to slide. 2, the lubricating oil is slid through each cylinder port 51 formed on the inner wall 5a of each cylinder bore 5, the side wall 6b of the piston 6, and the piston communication passages 64 and 65, as shown in FIG. Guided to the moving surface 6a.
[0029]
As a result, the lubricating oil is guided from the cylinder port 51 formed on the inner wall 5a of the cylinder bore 5 to the sliding surface 6a via the piston port 63 formed on the side wall 6b of the piston 6. Thus, unlike the case of supplying the lubricating oil from the working chamber side, it is possible to prevent the discharge flow rate of CO ₂ (compressible fluid) discharged from the compressor 100 from decreasing. Therefore, it is possible to supply the lubricating oil to the shoe 8 and the sliding surface 6a while suppressing a decrease in the efficiency of the compressor 100.
[0030]
Incidentally, the lubricating oil guided to the sliding surface 6a lubricates the contact surface between the sliding surface 6a and the shoe 8, and reaches the swing plate 10 through the lubrication hole 8a formed in the shoe 8. Lubricate the contact surface between 10 and the shoe 8.
By the way, the force F ₁ acting on the contact surface between the sliding surface 6 a and the shoe 8 is maximized when the compression reaction force acting on the piston 6 is maximized. Therefore, in this embodiment, when the compression reaction force is maximized to efficiently lubricate the contact surface between the sliding surface 6a and the shoe 8, the opening surfaces of both ports 51 and 63 are directly surfaced. As shown, both ports 51 and 63 are formed.
[0031]
Hereinafter, the positions of both ports 51 and 63 will be described in detail.
FIG. 4 shows the displacement of the piston 6 (hereinafter abbreviated as piston displacement) X, the pressure in the working chamber (hereinafter abbreviated as internal pressure) P, and the end face position of the piston 6 (hereinafter abbreviated as piston end face position) L. The solid line indicates the internal pressure P, and the alternate long and short dash line indicates the piston end face position L. Here, the end surface position (L) of the piston 6 means the distance from the end of the cylinder block 3 on the swash plate chamber 23a side to the end surface of the piston 6 on the working chamber side, as shown in FIG.
[0032]
As is apparent from FIG. 4, when the internal pressure P increases as the piston end surface position L (piston displacement X) increases and reaches the discharge pressure (the piston end surface position L at this time is changed to the discharge end surface position). CO ₂ is directed toward the radiator 110 until the discharge valve 20 is opened and the piston end face position L (piston displacement X) reaches top dead center (referred to as L ₁ and piston displacement X as discharge start displacement X ₁ ). Discharged.
[0033]
Therefore, the compression reaction force becomes maximum when the internal pressure P reaches the discharge pressure, and therefore, the piston end surface position L (piston displacement X) is the maximum from the discharge end surface position L ₁ (discharge start displacement X ₁ ). when located between the piston end surface position L _max (top dead center), it is sufficient to open surfaces of both ports 51,63 faces.
Specifically, the discharge end face position L ₁ is obtained by changing the stroke L _s (= L _max −L _min ) of the piston 6 to a compression ratio P _r (= P _d) which is a ratio between the discharge pressure P _d and the suction pressure P _s. / P _s ) (L ₁ = L _s / P _r ). Incidentally, the compression ratio P _r of CO ₂ cycle, usually because it is 2 to 3, and _{L 1 = L s / 3~L s} / 2.
[0034]
In determining the positions of the ports 51 and 63, in addition to the above-described points, the cylinder port 51 is prevented from directly communicating with the working chamber even when the piston 6 reaches the bottom dead center. That is, even when the piston 6 reaches the bottom dead center, the cylinder port 51 needs to be positioned on the swash plate chamber 2a side from the piston end surface position L.
[0035]
By the way, when the force F ₁ acting on the contact surface between the sliding surface 6a and the shoe 8 is maximized, the force F ₂ acting between the side wall 6b of the piston 6 and the inner wall 5a of the cylinder bore 5 (see FIG. 5). Is also the largest.
In the present embodiment, when the force F ₁ is maximized, that is, when the compression reaction force is maximized, the ports 51 and 63 are respectively set so that the opening surfaces of the ports 51 and 63 directly face each other. Since it is formed, the lubricating oil can be supplied to the side wall 6b and the inner wall 5a when the force F ₂ becomes maximum, and the side wall 6b and the inner wall 5a can be lubricated more effectively. it can.
[0036]
(Second Embodiment)
In the present embodiment, the cylinder groove 51a is eliminated, and as shown in FIG. 6, the piston groove that guides the lubricating oil to the portion corresponding to the piston port 63 in the side wall 6b of the piston 6 over the entire outer wall of the side wall 6b. 63a is formed.
(Third embodiment)
In this embodiment, as shown in FIGS. 7 and 8, not only when the groove width (dimension in the reciprocating direction of the piston 6) W of the cylinder groove 51a and the piston groove 63a is increased and the compression reaction force becomes maximum, The opening surfaces of both ports 51 and 63 are made to face in the whole stroke of the reciprocating motion of the piston 6.
[0037]
Incidentally, in the above-described embodiment, the lubricating oil is guided from the accumulator 140 to the cylinder port 51. For example, as shown in FIG. 9, an oil separator (refrigerant (CO ₂ ) and lubricating oil is used by utilizing a density difference. In the compressor 100 having the separator 24, the lubricating oil may be guided from the oil separator 24 to the cylinder port 51.
[0038]
In FIG. 9, the lubricating oil is guided from the oil separator 24 to the cylinder port 51 using the external pipe 25, but the communication path that guides the lubricating oil from the oil separator 24 to the cylinder port 51 in the cylinder block 3 and the rear cylinder 16. May be provided.
Further, both the cylinder groove 51a and the piston groove 63a may be provided simultaneously, or both the grooves 51a and 63a may be eliminated and only the cylinder port 51 and the piston port 63 may be provided.
[0039]
Further, in the above-described embodiment, the lubricating oil is guided from the accumulator 140 to the cylinder port 51. However, the receiver (disposed between the radiator 110 and the evaporator 130 is disposed between the gas phase CO ₂ (refrigerant) and the liquid phase. CO ₂ (refrigerant) may be derived from the separated gas phase CO ₂ that flows toward the (refrigerant) in the evaporator 130).
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a CO ₂ cycle.
FIG. 2 is a cross-sectional view of the swash plate compressor according to the first embodiment.
3 is a cross-sectional view taken along the line AA in FIG.
FIG. 4 is a graph showing the relationship between piston displacement X, internal pressure P, and piston end face position L.
FIG. 5 is an enlarged view of a piston portion of the swash plate compressor according to the first embodiment.
FIG. 6 is an enlarged view of a piston portion of a swash plate compressor according to a second embodiment.
FIG. 7 is an enlarged view of a piston portion of a swash plate compressor according to a third embodiment.
FIG. 8 is an enlarged view of a piston portion of a swash plate compressor according to a third embodiment.
FIG. 9 is a cross-sectional view of a swash plate compressor showing a modification.
FIG. 10 is an explanatory diagram for explaining “the problem to be solved by the invention”;
[Explanation of symbols]
5 ... Cylinder bore, 6 ... Piston, 6a ... Sliding surface, 8 ... Shoe,
51 ... Cylinder port, 51a ... Cylinder groove, 63 ... Piston port,
63a ... piston port, 64, 65 ... piston communication passage.

Claims (7)

A swash plate compressor that sucks and compresses a compressible fluid,
A shaft (1) that rotates with driving force;
Housings (2, 3, 16) for accommodating the shaft (1) and rotatably holding the shaft (1);
A cylinder bore (5) formed in the housing (2, 3, 16) parallel to the axial direction of the shaft (1);
A piston (6) reciprocating within the cylinder bore (5);
A swing member (10) disposed in the housing (2, 3, 16) and swinging in conjunction with rotation of the shaft (1);
A spherical sliding surface (6a) formed on the swing member (10) side of the piston (6);
A shoe (8) that comes into contact with the sliding surface (6a) and that oscillates the swing plate (10) and the piston (6);
A cylinder port (51) through which lubricating oil is guided and opened in the inner wall (5a) of the cylinder bore (5);
A piston port (63) opening in a side wall (6b) facing the inner wall (5a) of the cylinder bore (5) of the piston (6);
A communication path (64, 65) communicating from the piston port (63) through the inside of the piston (6) to the sliding surface (6a),
The cylinder port (51) and the piston port (63) are arranged so that the opening surfaces of both the ports (51, 61) face when the compression reaction force acting on the piston (6) becomes maximum. A swash plate compressor characterized by being formed. A swash plate compressor that sucks and compresses a compressible fluid,
A shaft (1) that rotates with driving force;
Housings (2, 3, 16) for accommodating the shaft (1) and rotatably holding the shaft (1);
A cylinder bore (5) formed in the housing (2, 3, 16) parallel to the axial direction of the shaft (1);
A piston (6) reciprocating within the cylinder bore (5);
A swing member (10) disposed in the housing (2, 3, 16) and swinging in conjunction with rotation of the shaft (1);
A spherical sliding surface (6a) formed on the swing member (10) side of the piston (6);
A shoe (8) that comes into contact with the sliding surface (6a) and that oscillates the swing plate (10) and the piston (6);
A cylinder port (51) through which lubricating oil is guided and opened in the inner wall (5a) of the cylinder bore (5);
A piston port (63) opening in a side wall (6b) facing the inner wall (5a) of the cylinder bore (5) of the piston (6);
A communication path (64, 65) communicating from the piston port (63) through the inside of the piston (6) to the sliding surface (6a),
The slanted oil is introduced directly into the cylinder port (51) from a tank means (140) for separating a gas-phase refrigerant and a liquid-phase refrigerant provided in the refrigeration cycle. Plate type compressor. The swash plate compressor according to claim 2, wherein the lubricating oil is guided directly to the cylinder port (51) through an external pipe (150, 25).   The swash plate compressor according to claim 2, wherein the tank means is a receiver disposed between a radiator (110) and an evaporator (130) in the refrigeration cycle. A cylinder groove (51a) for guiding lubricating oil is formed in the inner wall (5a) of the cylinder bore (5) corresponding to the cylinder port (51) over the entire circumference of the inner wall (5a). The swash plate type compressor according to any one of claims 1 to 4 . A piston groove (61a) that guides lubricating oil is formed in the portion of the side wall (6b) of the piston (6) corresponding to the piston port (63) over the entire outer wall of the side wall (6b). The swash plate compressor according to any one of claims 1 to 5 , wherein the compressor is provided. A compressor for a refrigeration cycle, wherein the swash plate compressor according to any one of claims 1 to 6 is used as a compressor that compresses the compressive fluid to a critical pressure or higher.

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