JPH10246182A - Swash plate type compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply lubricating oil to a shoe and a slide surface while suppressing a decrease of efficiency of a compressor, in the swash plate type compressor suction compressing a compressive fluid. SOLUTION: A compressor is provided with a cylinder port 51 opened to an inner wall 5a of a cylinder bore 5 also guided with lubricating oil, piston port 63 opened to a side wall 6b of a piston 6, and piston communication paths 64, 65 communicating to a slide surface 6a from the piston port 63 via the inside of the piston 6. In this way, a delivery flow amount of compressive fluid delivered from a swash plate type compressor 100 can be prevented from reducing. Accordingly, while suppressing a decrease of efficiency of the swash plate type compressor, lubricating oil can be supplied to a shoe 8 and the slide surface 6a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a swash plate type compressor, is effective as carbon dioxide (CO ₂₎ compressor applied refrigeration cycle high refrigeration cycle of the discharge pressure of the refrigerant and the like .

[0002]

2. Description of the Related Art In recent years, a refrigeration cycle using carbon dioxide (CO ₂ ) as a refrigerant (hereinafter referred to as a CO ₂ cycle) has been actively studied as a measure against defluorocarbon in an air conditioner (refrigeration cycle). . In this CO ₂ cycle, the discharge pressure of the compressor is higher than that of a normal refrigeration cycle using chlorofluorocarbon as a refrigerant (hereinafter, abbreviated as refrigeration cycle). Therefore, the compressor used in the refrigeration cycle must be used as it is. Can not.

[0003] In a swash plate compressor, the oscillating plate (swash plate) and the piston slide while a shoe is in contact with a spherical sliding surface formed at the tip of the piston. The compression reaction force is intensively applied to the shoe and the sliding surface. For this reason, when a high discharge pressure is required as in a CO ₂ cycle,
It is necessary to sufficiently lubricate the sliding surface and the shoe.

By the way, the discharge pressure in the case of Freon is about 1.
Is 6 MPa, the discharge pressure in the case of CO ₂ is about 12MPa exceeding CO ₂ the critical pressure (7.4 MPa). In the case of a non-compressible fluid such as a hydraulic pump that sucks and compresses, in order to satisfy the above-mentioned need, for example,
As described in Japanese Patent Application Laid-Open No. 5-113173, a communication passage penetrating in the longitudinal direction of the piston from the working chamber (compression chamber) side to the sliding surface is provided, and hydraulic oil sucked into the working chamber is guided to the sliding surface. That means is adopted.

[0005]

However, when the means described in the above-mentioned publication is applied to a swash plate type compressor that sucks and compresses a compressible fluid like a CO ₂ cycle, the following problems occur. Occurs. That is, in the means described in the above publication, as shown in FIG. 10, since the communication path a is formed in the piston 6, even if the piston 6 reaches the top dead center, the swing plate 10 and the shoe 8 The hydraulic fluid leaked into the swash plate chamber from the gap between the two and the discharge flow rate is reduced by the volume of the communication passages a, b, and c.

[0006] Incidentally, since the decreasing discharge flow rate is small in terms of the volume flow rate, the decrease in efficiency due to the decreasing discharge flow rate can be almost neglected in the case of sucking and compressing an incompressible fluid like a hydraulic pump. However, since the compressor applied to the refrigeration cycle included in the CO ₂ cycle sucks and compresses a compressible fluid such as chlorofluorocarbon or CO ₂ as a refrigerant, the refrigerant density at the time of discharge is high, and the decreasing discharge flow rate is Even if it is small in the flow rate conversion, it becomes large when converted into the mass flow rate. Therefore, when the means described in the above publication is applied to a compressor for a refrigeration cycle (including a CO ₂ cycle), a problem occurs that the efficiency of the compressor is greatly reduced.

In view of the above, the present invention provides a swash plate type compressor for sucking and compressing a compressible fluid, in which lubricating oil is supplied to a shoe and a sliding surface while suppressing a decrease in compressor efficiency. With the goal.

[0008]

The present invention uses the following technical means to achieve the above object. Claim 1
According to the invention described in Item 4, in the swash plate type compressor that sucks and compresses a compressible fluid, the cylinder port (51) that opens to the inner wall (5a) of the cylinder bore (5) and that lubricating oil is guided, and the piston (6). ), And a communication path (64, 65) communicating from the piston port (63) to the sliding surface (6a) through the inside of the piston (6) to the sliding surface (6a). It is characterized by.

Thus, the lubricating oil flows 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). Is guided to the sliding surface (6a), so that the discharge flow rate of the compressible fluid discharged from the swash plate type compressor is reduced, unlike the lubricating oil supplied from the working chamber side as described in the above publication. Can be prevented. Therefore, lubricating oil can be supplied to the shoe (8) and the sliding surface (6a) while suppressing a decrease in efficiency of the swash plate type compressor.

The cylinder port (5) of the inner wall (5a) of the cylinder bore (5) is defined in claim 2.
A cylinder groove (51a) for guiding lubricating oil over the entire circumference of the inner wall (5a) may be formed in a portion corresponding to (1). As described in claim 3, a piston groove for guiding lubricating oil over the entire outer wall of the side wall (6b) to a portion of the side wall (6b) of the piston (6) corresponding to the piston port (63). (61a) may be formed.

By the way, the sliding surface (6a) and the shoe (8)
The force (F ₁ ) acting on the contact surface with the piston becomes maximum when the compression reaction force acting on the piston (6) becomes maximum. According to the fourth aspect of the invention, when the compression reaction force acting on the piston (6) becomes maximum, the cylinder port (51) and the piston port (63) are connected to both ports (51, 61). It is characterized in that it is formed so that the opening surface faces.

Therefore, in the present invention, the sliding surface (6a)
The contact surface between the shoe and the shoe (8) can be efficiently lubricated. According to a fifth aspect of the present invention, the swash plate type compressor according to any one of the first to fourth aspects is used as a compressor for compressing the compressible fluid to a pressure not lower than the critical pressure.

The reference numerals in parentheses of the above means indicate the correspondence with the concrete means described in the embodiments described later.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; (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, and FIG. 1 shows a swash plate type compression according to the present invention. A CO ₂ cycle using a compressor (hereinafter simply referred to as a compressor) is applied to an air conditioner for a vehicle.

In FIG. 1, reference numeral 100 denotes a compressor which is driven by a driving force from an engine (not shown) for driving a vehicle, and compresses CO ₂ in a gaseous state. 110 is the compressor 10
A radiator (gas cooler) for exchanging heat between the CO ₂ compressed at 0 and outside air or the like to cool the radiator, and 120 is a radiator 1
10 is a pressure control valve that controls the outlet pressure of the radiator 110 according to the CO ₂ temperature at the outlet side. The pressure control valve 120 also serves as a pressure reducer controls the outlet pressure of the radiator 110, CO _2, the pressure control valve 1
At 20, the pressure is reduced to CO ₂ in a low-temperature, low-pressure gas-liquid two-phase state.

Reference numeral 130 denotes an evaporator (heat absorber) serving as air cooling means in the passenger compartment, and CO ₂ in a gas-liquid two-phase state is supplied to the evaporator 13.
At the time of vaporization (evaporation) within 0, the latent heat of evaporation is taken from the air in the vehicle interior to cool the air in the vehicle interior. Reference numeral 140 denotes an accumulator (tank means) that separates CO ₂ in a gaseous state and CO ₂ in a liquid state and temporarily stores CO ₂ in a gaseous state.

FIG. 2 shows an axial cross section of the compressor 100. Reference numeral 1 denotes a shaft which rotates by obtaining a driving force from an external drive source (vehicle running engine or the like) via an electromagnetic clutch (not shown). The shaft 1 is rotatably held by a radial bearing 101 provided 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.

A space (hereinafter referred to as a swash plate chamber) 2a formed by the front housing 2 and the cylinder block 3 in the shaft 1 has an inclination with a predetermined angle with respect to the shaft 1. The swash plate 4 on which the surface 4a is formed is pressed into the shaft 1, whereby the shaft 1 and the swash plate 4 rotate integrally. Further, a surface 4 perpendicular to the shaft 1 is provided on the side of the swash plate 4 opposite to the inclined surface 4a.
b, and a thrust bearing 102 is disposed between the surface 4 b and the front housing 2 to form a swash plate 4.
Opposing the compression reaction force acting on the

In the cylinder block 3, there are 6 cylinders parallel to the shaft 1 and circumferentially around the shaft 1.
Six cylinder bores 5 penetrating the cylinder block 3 in the axial direction of the shaft 1 are formed at equally dividing positions (see FIG. 3). Each cylinder bore 5 has a shaft that contacts the inner wall of the cylinder bore 5 while contacting the inner wall of the cylinder bore 5. A piston 6 reciprocating in the axial direction is inserted.

Then, between the piston 6 and the swash plate 4,
A swing member 7 that swings in the axial direction of the shaft 1 around the shaft 1 is provided, and the swing member 7 is
The piston 6 is connected via a brass shoe 8 slidably connected to a spherical sliding surface 6a formed at the end of the piston 6.
And swingably connected. The shoe 8 is provided with a retainer 9 serving as a holding member for the shoe 8 and a rocking plate 10 which is in contact with the rolling element 103a of the thrust bearing 103 disposed on the swash plate 4 and rotatably couples with the swash plate 4. And is slidably held on the swinging plate 10.

Incidentally, the rocking plate 10 has a thrust bearing 10
3 also serves as a bearing race, and the thrust bearing 103
Is to oppose a compression reaction force acting on the swinging member 7 via the piston 6. Also, the retainer 9 and the shaft 1
A spacer 11 that is rotatably in contact with the retainer 9 is disposed between the spacer 11 and the spacer 11.
The contact surface with the swash plate 4 is formed in a substantially spherical shape with the swash plate 4 side being convex so as to be able to respond to a change in the inclination angle of the swash plate 4. A spring 12 generates an elastic force for pressing the spacer 11 toward the swash plate 4.
A gap 11a is formed between the two. The gap 11a prevents frictional resistance between the spacer 11 and the shaft 1.

A valve plate 13 is disposed at an end of the cylinder block 3 so as to oppose the piston 6 and close one end of the cylinder bore 5. The valve plate 13 communicates with the cylinder bore 5. A plurality of suction ports 14 and discharge ports 15 are formed. Then, the valve plate 13 and the rear housing 16
And a suction chamber 17 that distributes refrigerant sucked from a suction port of a compressor (not shown) to each suction port 14.
And a discharge chamber 18 that collects refrigerant discharged from each discharge port 15 and guides the refrigerant to a discharge port (not shown) of the compressor.

A reed valve-shaped suction valve 19 is provided on the piston 6 side of each suction port 14, and a reed valve-shaped discharge valve 20 is similarly provided on the discharge chamber 18 side of each discharge port 15. Are arranged. The maximum opening of the discharge valve 20 is regulated by the stopper 21.
The stopper 20 and the stopper 21 are fixed together with the valve plate 13 by the cylinder block 3 and the rear housing 16.

Incidentally, a lip seal 22 prevents the refrigerant in the swash plate chamber 2a from leaking out of the compressor.
23 is an O-ring made of nitrile rubber. By the way, the piston 6 is composed of a cylindrical piston body 61 and a connecting portion 62 having a sliding surface 6a formed thereon. As shown in FIG. It is integrally formed from steel (SUJ-2).

A side wall 6b of the piston main body 61 (piston 6) facing the inner wall of the cylinder bore 5 has:
The piston port 63 is open, and the piston port 63 communicates with the sliding surface 6 a through piston communication passages 64 and 65 formed inside the piston 6. A cylinder port 51 is opened in the inner wall 5a of each cylinder bore 5.
The accumulator 1 provided in the CO ₂ cycle
The lubricating oil separated from CO _{2 in the} outer pipe 150
(See FIG. 1).

Incidentally, not only in the CO ₂ cycle but also in a refrigeration cycle using chlorofluorocarbon, lubricating oil and 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. The inner wall 5 of each cylinder bore 5 corresponding to each cylinder port 51
a, a cylinder groove 51a is formed over the entire circumference of the inner wall 5a of the cylinder bore 5, and the lubricating oil guided to the cylinder port 51 by the cylinder groove 51a is supplied to the entire circumference of the inner wall of the cylinder bore 5 (all the side wall of the piston 6). Lap).

As shown in FIG. 3, each of the cylinder ports 51 communicates with three cylinder communication passages 52 formed in the cylinder block 3.
Is led to the inlet 53. By the way,
53a and 53b are closed by a lid member after the cylinder communication passage 52 is formed. Next, features of the present embodiment will be described.

According to the present embodiment, as in the means described in the above-mentioned publication, a communication passage penetrating from the working chamber (space formed by the cylinder bore and the piston) side to the sliding surface 6a is provided, and fluid in the working chamber is provided. Unlike the one that leads to the sliding surface 6a, as shown in FIG. 2, the lubricating oil passes 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. And is guided to the sliding surface 6a.

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. And lubricating oil is supplied from the working chamber side as described in
It is possible to prevent the discharge flow rate of CO ₂ (compressible fluid) discharged from 00 from decreasing. Therefore, lubricating oil can be supplied to the shoe 8 and the sliding surface 6a while suppressing a decrease in efficiency of the compressor 100.

Incidentally, the lubricating oil guided to the sliding surface 6a is:
While lubricating the contact surface between the sliding surface 6a and the shoe 8,
The lubrication hole 8a formed in the shoe 8 reaches the rocking plate 10 and lubricates the contact surface between the rocking plate 10 and the shoe 8. By the way, the force F acting on the contact surface between the sliding surface 6a and the shoe 8
₁ becomes maximum when the compression reaction force acting on the piston 6 becomes maximum. Therefore, in this embodiment,
In order to efficiently lubricate the contact surface between the sliding surface 6a and the shoe 8, when the compression reaction force is maximized, both ports 51, 6
3 so that the opening faces of the ports 3 directly face each other.
3 are formed respectively.

Hereinafter, the positions of the ports 51 and 63 will be described in detail. FIG. 4 shows the displacement X of the piston 6 (hereinafter abbreviated as piston displacement), 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 dashed line indicates the piston end face position L. Here, the end face position (L) of the piston 6
5 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.

As is apparent from FIG. 4, the internal pressure P increases in accordance with the rise of the piston end surface position L (piston displacement X).
There continue to rise, upon reaching the discharge pressure (referred to as the discharge end face position L ₁ of the piston end surface position L at this time is called the piston displacement X and the discharge start displacement X _1.) The discharge valve 20 is opened,
Until the piston end surface position L (piston displacement X) reaches the top dead center, CO ₂ is discharged toward the radiator 110.

Therefore, the maximum compression reaction force is as follows.
Since the internal pressure P has reached the discharge pressure, the piston end
The surface position L (piston displacement X) is the discharge end surface position L₁(Spit
Discharge start displacement X₁) To the maximum piston end face position L_max(Up
When located between (dead center), both ports 51 and 63 open.
What is necessary is just to make a mouth face. Specifically, the discharge end face
Position L₁Is the stroke L of the piston 6_s(= L_max−
L_min) Is the discharge pressure P_dAnd suction pressure P_sIs the ratio
Compression ratio P_r(= P_d/ P _s) (L₁
= L_s/ P_r). By the way, CO_TwoCycle compression ratio P_r
Is usually 2-3, so L₁= L_s/ 3 to L_s/
It becomes 2.

In determining the positions of the ports 51 and 63, in addition to the above-described points, even when the piston 6 reaches the bottom dead center, the cylinder port 51 does not directly communicate with the working chamber. So that the piston 6
The cylinder port 51 even when
Must be located closer to the swash plate chamber 2a than the piston end face position L.

By the way, when a force F ₁ acting on the contact surface between the sliding surface 6a and the shoe 8 is maximum, the piston 6
Force F ₂ acting between the inner wall 5a of the side wall 6b and the cylinder bore 5 (see FIG. 5) also becomes maximum. In the present embodiment, when the force F ₁ is maximum, that is, when the compression reaction force is maximum, the ports 51 and 63 are respectively connected so that the opening surfaces of the ports 51 and 63 face directly. because it is formed, it is possible to force F ₂ to supply lubricating oil to the lubricating oil when maximized and the side wall 6b and the inner wall 5a, is possible to lubricate the side wall 6b and the inner wall 5a effectively it can.

(Second Embodiment) In this embodiment, the cylinder groove 51a is eliminated, and as shown in FIG. 6, a portion of the side wall 6b of the piston 6 corresponding to the piston port 63 is provided around the entire outer wall of the side wall 6b. Piston groove 63 that guides lubricating oil over
a is formed. (Third Embodiment) In the present embodiment, as shown in FIGS. 7 and 8, 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 is maximized. The opening surfaces of both ports 51 and 63 face the entire stroke of the reciprocating motion of the piston 6 as well as when it comes to.

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 (a refrigerant (CO ₂ ) and In the compressor 100 having a
Lubricating oil is supplied from the oil separator 24 to the cylinder port 51.
You may lead to.

In FIG. 9, the lubricating oil is introduced from the oil separator 24 to the cylinder port 51 by using the external pipe 25.
A communication path for guiding lubricating oil from the oil separator 24 to the cylinder port 51 may be provided in 6. Further, both the cylinder groove 51a and the piston groove 63a may be provided at the same time, or both the grooves 51a and 63a may be omitted and only the cylinder port 51 and the piston port 63 may be provided.

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 to provide gaseous CO ₂ (refrigerant)) And the liquid-phase CO ₂ (refrigerant) may be separated and guided from the gas-phase CO ₂ (refrigerant) flowing out toward 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 type compressor according to the first embodiment.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a graph showing a relationship between a piston displacement X, an internal pressure P, and a piston end surface position L.

FIG. 5 is an enlarged view of a piston portion of the swash plate type compressor according to the first embodiment.

FIG. 6 is an enlarged view of a piston portion of the swash plate type compressor according to the second embodiment.

FIG. 7 is an enlarged view of a piston portion of the swash plate type compressor according to the third embodiment.

FIG. 8 is an enlarged view of a piston portion of the swash plate type compressor according to the third embodiment.

FIG. 9 is a sectional view of a swash plate type 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, 6
4, 65: piston communication passage.

Claims (5)

[Claims] 1. A swash plate type compressor for sucking and compressing a compressible fluid, wherein a shaft (1) rotating by obtaining a driving force, the shaft (1) is housed and the shaft (1) is housed. Housing (2, 3, 1) for rotatably holding
6) and the shaft (1) on the housing (2, 3, 16).
A cylinder bore (5) formed in parallel with the axial direction of the piston, a piston (6) reciprocating in the cylinder bore (5), and a shaft (1) disposed in the housing (2, 3, 16). The swing member (1) that swings in conjunction with the rotation of
0), a spherical sliding surface (6a) formed on the side of the oscillating member (10) of the piston (6), and the sliding surface (6a). Shoe (8) for swingably connecting the piston (6) to the piston (6).
The lubricating oil is guided to the inner wall (5) of the cylinder bore (5).
a) a piston port (63) opening to a side wall (6b) of the piston (6) facing the inner wall (5a) of the cylinder bore (5); 63) through the interior of the piston (6) to the sliding surface (6a).
(4, 65). 2. An inner wall (5a) of the cylinder bore (5).
The cylinder groove (51a) which guides lubricating oil over the whole circumference of the inner wall (5a) is formed in a portion corresponding to the cylinder port (51) among them. Swash plate type compressor. 3. A piston groove (61a) for guiding lubricating oil over the entire outer wall of the side wall (6b) in a portion of the side wall (6b) of the piston (6) corresponding to the piston port (63). 3. The swash plate type compressor according to claim 1, wherein 4. The cylinder port (51) and the piston port (63) are connected to the two ports (5) when a compression reaction force acting on the piston (6) is maximized.
The swash plate type compressor according to any one of claims 1 to 3, wherein the opening surfaces of (1, 61) are formed so as to face each other. 5. A compressor for a refrigeration cycle, wherein the swash plate type compressor according to any one of claims 1 to 4 is used as a compressor for compressing to a pressure equal to or higher than a critical pressure of a compressible fluid.