JPS6310311B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a refrigerant compressor.

A refrigerant having a suction and discharge cavity and a crankcase comprising a compressor mechanism for allowing gaseous refrigerant to enter the crankcase under pressure from the discharge cavity with an accompanying lubricant and vented to the suction cavity. Compressors are known (eg US Pat. No. 4,145,163).

The lubrication system for refrigerant compressors equipped with wobble plate drive mechanisms uses pressurized oil circulation by splashing and/or pumps, so the oil entrained in the refrigerant is used to prevent critical damage to the compressor. Advances have been made to simpler and less expensive passive type systems for lubricating rotating bearing surfaces, particularly those of wobble plates. However, conventional passive type lubrication systems typically rely on a compressor mechanism located within the crankcase, which can be formed as part of the compressor's refrigerant circuit, including the compressor's suction or exhaust refrigerant passages. Therefore, conventional passive type lubrication systems require that refrigerant gas pressure be generated within the crankcase to maintain optimum compressor performance and/or to control compressor displacement in the compressor suction circuit for crankcase pressure control. It is usually not suitable for types of compressors that must be vented to

The present invention advantageously utilizes crankcase ventilation to properly control critical bearing surfaces of compressor mechanisms under all operating conditions and in a simple, inexpensive, passive manner that does not require oil pumps or other forms of pressurized lubrication. To this end, the refrigerant compressor according to the invention has a passive lubrication system that vents crankcase pressure into a suction cavity between the rotating bearing surfaces of the compressor mechanism. a lubrication and ventilation passage for lubricating the bearing surface with an entrained lubricant and separating some of the entrained lubricant by centrifugal action at the bearing surface and returning it to the crankcase for further compressor lubricant use; means for substantially reducing the amount of lubricant actually delivered from the crankcase to the compressor suction cavity and available for evacuation from the compressor in the discharge cavity and returning to the crankcase by said centrifugal action. It is characterized in that a certain amount of lubricant is retained therein and is always available for further compressor lubrication.

In a preferred form of the refrigerant compressor according to the present invention, the variable displacement axial piston type refrigerant compressor is a demand responsive compressor that operates to bleed or vent the crankcase to the suction section to provide desired displacement control. The refrigerant gas pressure difference between the crankcase and the compressor suction is controlled by a hydraulic valve so that it can be automatically varied according to demand. In accordance with the present invention, a crankcase-suction vent connects the crankcase to the compressor suction between critical bearing surfaces of the compressor drive mechanism and lubricates these bearing surfaces with entrained lubricant in the gaseous refrigerant. Bleed or vent passage means are provided for centrifugally separating some of the entrained lubricant at the bearing surface and returning it to the crankcase for further compressor lubrication. the result,
The amount of lubricant actually delivered to the compressor suction and available for circulation within the refrigerant circuit served by the compressor is substantially reduced;
The amount of lubricant returned to the crankcase by said centrifugal action is retained therein and becomes available for further lubrication of the compressor.

In Fig. 1, a conventional condenser 12 and an orifice pipe 1 are installed between the discharge side and the suction side of the compressor.
4. A variable displacement refrigerant compressor 10 of a variable angle wobble plate type is shown connected in an automobile air conditioning system in which an evaporator 16 and an accumulator 18 are arranged in that order. Compressor 1
0 has a cylinder block 20 having a head 22 and a crankcase 24 hermetically clamped to each end thereof. In the center of the compressor are a cylinder block 20 and a crankcase 24.
A drive shaft 26 is supported by radial needle bearings 28 and 30, respectively, and is axially held inward of needle bearing 28 by a thrust washer 32 and inward of radial needle bearing 30 by a thrust needle bearing 34. The drive shaft 26 is connected to the crankcase 24 so as to be connected to an automobile engine (not shown) by an electromagnetic clutch 36 mounted on the crankcase.
It is driven from the engine by a belt 38 that passes through the clutch and engages a pulley 40 on the clutch.

Cylinder block 20 has five axial cylinders 42 (only one shown) extending therethrough;
The cylinders 42 are evenly angularly spaced about and evenly radially spaced from the axis of the drive shaft 26. The cylinders 42 extend parallel to the drive shaft 26 and have seals 4 within each cylinder.
A piston 44 having a number 6 is mounted for reciprocating sliding movement. Another piston rod 48 is connected to a non-rotating ring-shaped wobble plate 50 received around the drive shaft 26 aft of each piston 44. Each piston rod 48 has a retainer 56 installed in place.
It is connected to its respective piston 44 by a spherical rod end 52 held in a socket 54 on the rear side of the piston. The opposite end of each piston rod 48 is connected to the wobble plate 50 by a similar spherical rod end 58 held in a socket 60 on the wobble plate by a split retaining ring 62 that snaps into the wobble plate.

The non-rotating wobble plate 50 is mounted at its inner diameter 64 onto the journal 66 of the rotary drive plate 68;
Further, it is held in the axial direction with respect to the thrust needle bearing 70 by a thrust washer 71 and a retaining ring 72. As shown in FIG. 2, drive plate 68 is pivotally connected at journal 66 to a sleeve 76 slidably mounted on drive shaft 26 by a pair of pivot pins 74, each pin being A common axis of the pivot pins is mounted in alignment holes 78 and 80 on opposite sides of radially outwardly extending bosses 82 on journal 66 and sleeve 76 , with the common axis of the pivot pins
It intersects the axis of the drive shaft 26 at right angles to allow the wobble plate 50 to be tilted with respect to the drive shaft.

The drive shaft 26 is connected to the drive plate 6 by a protrusion 84 that freely passes through a longitudinal slot 86 in the sleeve 76.
8. This drive projection 84 is threaded at one end at right angles to the drive shaft 26 and extends radially outwardly beyond the journal 66 where it forms a guide slot 88 for guiding the slope of the drive plate 68 and wobble plate 50. It is equipped with The drive projection 84 engages on one side in a lateral flat manner at 90 with an ear 92 integrally formed with the drive plate 68 and is perpendicular to the drive shaft and the sleeve 76 extends along the drive shaft 26 . It is held against said ear by a transverse pin 94 which slides in and is guided by a guide slot 88 as it moves along. The transverse pin 94 has at one end an enlarged head 96 that engages a projection on one side of the slot 88 and adjacent the other end a transverse hole 98 in the drive plate lug 92 in which it is retained by a retaining ring 100. It is held in place at its ears 92 on the drive plate 68 by being received therein. Although the wobble plate 50 can tilt together with the rotary drive plate 68, it is prevented from rotating together with the rotary drive plate by a guide pin 102 to which a ball guide 104 is slidably attached and held on the wobble plate. The guide pin 102 is press-fitted at both ends into the cylinder block 20 and crankcase 24 parallel to the drive shaft 26, and the ball guide 104 is slidably mounted for reciprocating radial movement within the wobble plate 50. It is held between semi-cylindrical guide shoes 106 (only one shown).

The drive protrusion arrangement for the drive plate 68 and the anti-rotation guide arrangement for the wobble plate 50 are respectively known (e.g., U.S. Pat. No. 4,175,915 and U.S. Pat.
4297085). With such an arrangement,
As the sleeve 76 moves along the drive shaft 26 while the drive shaft 26 drives the drive plate 68 in the direction of the arrow in FIG. An essentially constant top dead center position for each piston 44 is provided by the pin follower 94, which is radially movable along its guide slot or cam track 88. As a result, the angle of the wobble plate 50 changes with respect to the axis of the drive shaft 26 between the large angle position shown by the solid line in the first figure, which is a complete stroke, and the zero angle virtual line position shown in the figure, which is a zero stroke. The process of
Therefore, the displacement (capacity) of the compressor is varied steplessly between these two extremes. As shown in FIG. 1, the sleeve 7 is installed in the groove of the drive shaft 26 and one end thereof is moved to the zero wobble angle position.
A split ring return spring 107 is provided which is adjusted to initiate a return movement by being engaged by 6.

The working end of the cylinder 42 is covered by a valve plate 108 which, with an intake or suction valve disc 110 and an exhaust or exhaust valve disc 112 located on either side thereof, connects it to the cylinder block 20 and its head. It is clamped between 22. Head 22 includes a suction cavity or chamber 114 communicated via an outer port 116 to receive gaseous refrigerant from an accumulator 18 downstream of evaporator 16. The suction cavity 114 opens to the inlet 118 of the valve plate 108 at the working end of each cylinder 42, where refrigerant is passed through each reed valve 120 integrally formed with the suction valve disc 110 at these locations. Each cylinder is entered during its suction stroke. During the compression stroke, a discharge port 12 is opened to the working end of each cylinder 42.
2, the compressed refrigerant is discharged from the discharge cavity or chamber 12 of the head 22 by means of a discharge reed valve 126 formed integrally with the discharge valve disc 112 at these locations.
4, but the degree of opening of each discharge reed valve is limited by a rigid support strap 128 riveted to valve plate 108 at one end.
The compressor discharge cavity 124 is connected to deliver compressed gaseous refrigerant to the condenser 12, from where it is sent back to the evaporator 16 via the orifice tube 14 to complete the refrigerant circuit shown in FIG. do.

The wobble plate angle, and therefore the compressor displacement, is controlled by controlling the refrigerant gas pressure within the sealed interior 129 of the crankcase behind the piston 44 relative to the suction pressure. In this type of control, the angle of the wobble plate is such that when the crankcase suction pressure difference slightly exceeds the set suction pressure control point, the wobble plate angle decreases, thereby reducing the compressor capacity. It is determined by the force balance on the piston that produces a net force on the piston with a pivoting moment about the pivot pin 74. One practice for such control is to maintain air bleed or venting from the crankcase to the suction line so that there is no crankcase suction pressure difference, such as when the compressor suction pressure is energized and the associated suction pressure has high air conditioning capacity demands. Use a control valve that is automatically activated by a bellows or diaphragm that activates when the control point is exceeded. As a result, wobble plate 50 tilts to its full stroke high angle position shown in FIG. 1 and establishes maximum displacement. on the other hand,
When the air conditioning capacity demand becomes low and the suction pressure drops to the control point, the control valve with suction pressure activation is activated to cut off the crankcase ventilation communication with the suction section and to close the communication between the compressor outlet and the crankcase. or allow the pressure therein to increase as a result of blow-by of the gas past the piston. This is due to the wobble plate pivot pin 74 which reduces the wobble plate angle during a slight rise, thereby reducing the compressor displacement.
This has the effect of increasing the crankcase suction pressure differential which generates a net force on the piston with a pivoting moment about the piston.

Another, more advanced method of control is to use a variable displacement control valve system 130 that automatically controls compressor displacement or capacity as required in response to compressor discharge and suction pressures. In this latter control valve arrangement, as in the former, ventilation is provided to the compressor suction of the crankcase in order to control the crankcase pressure and thereby the compressor displacement, and this ventilation is maintained under all operating conditions. It is utilized in accordance with the present invention to provide adequate lubrication of the critical bearing surfaces of a compressor in a simple, low cost, passive manner without the need for oil pumps or other forms of pressurized lubrication.

A preferred embodiment of a passive lubrication system according to the present invention is shown incorporated into an advanced control valve assembly 130, and a complete understanding of this control valve and its operation is required to understand this improved lubrication system. It helps to understand. As shown in FIGS. 1 and 3, the control valve assembly 130 includes a valve housing 132, which in the preferred embodiment is integrally formed within the head 22.
2, an open outer end 14 and a closed inner end 135, and a stepped hole portion 13 that gradually becomes smaller.
6, 138, 140, 142 and a stepped blind hole 1
It has 33. Innermost maximum diameter hole portion 136
radial port 144 and passageway 146 in head 22.
It opens into a suction cavity 114 which is also located in the head of the compressor.

This passive lubrication system includes a radial port 148 in the head 22, a port 150 in the valve plate 108, passages 152 and 154 in the cylinder block 20, a central axial passage 156 in the drive shaft 26, and a radial passage 158 intersecting the central axial passage 156 in the drive shaft 26. , one of the drive plate pivot pins 74
Adjacent bore portions 1 of smaller diameter through lubrication and ventilation passage means formed by a central axial passage 160 in the wobble plate 50 along the drive plate journal 66 and through its thrust needle bearing 70.
38 is incorporated into the control valve device by connecting it to the inside 129 of the crankcase (the second
(See Figure and Figure 3). As detailed further below,
The crankcase ventilation passage thus provided, apart from its crankcase pressure control function, ensures lubrication of the critical rotating bearing surfaces of the wobble plate mechanism by such routing.

In the valve itself, the smaller diameter adjacent bore portion 140 of the valve housing also enters the interior 129 of the crankcase 24 and, by direct route, into the head 2.
2 through a radial port 162 in the valve plate 108, a port 164 in the valve plate 108, and a passage 166 in the cylinder block 20. The adjacent minimum diameter bore portion 142 at the closed end 136 of the stepped valve body bore opens directly into the discharge cavity 124 through a radial opening 168 in the head.

A cup-shaped valve bellows cover 170 having a closed outer side 172 and an open inner end 174 extends over the stepped hole 13 of the housing at the large bore portion 136.
3 in a fixed position within the open end 134 of the large bore portion 136, the positioning of which engages a shoulder 178 at the stepped outer end of the large bore portion 136, as best seen in FIG. Determined by a cylindrical flange 176 on the cover. The seal is then provided by an O-ring 180 received within the inner groove of large bore portion 136 and in sealing contact with cylindrical land 182 of bellows cover 170.
Retention of the bellows cover 170 is received within the inner groove of the bore end 134 and the bellows cover flange 1
provided by a retaining ring 184 that engages the outside of 76. Therefore, the closed end 1 of the bellows cover 170
72 is located within and closes the opening 134 of the valve housing 132, with the open end 174 facing inwardly toward the closed end 135 of the valve housing.

Concentrically positioned within the bellows cover 170 is an evacuated bellows 186 seated against the closed end 172 of the cover. Bellows 1
86 is a cup-shaped corrugated thin metal casing 187
, which receives a spring seat member 188 at its closed, seated end. The other end of the bellows casing 187 is hermetically closed by and sealingly secured to an end piece 190 which extends centrally through the output rod 191. bellows 186
is formed by the exterior of the bellows and the interior of the bellows cover 170 and is connected to the control valve housing 1 through a radial opening 194 in the bellows cover 170.
The annular pressure control cell 192, which is continuously opened to the suction pressure communication ports 144 of 32, is evacuated so as to expand and contract in response to pressure changes within the annular pressure control cell 192. A compression coil spring 196 is arranged within the bellows to
extending between two rigid end members 188 and 190. The spring 196 thus captured maintains the bellows in an extended position that produces an outward force on the output rod 191 at all times. The output rod 191 is tapered at its inner end so that it can be guided within the blind hole 202 of the inner seat member 188 during contraction of the bellows. The opposite external end 20 of the output rod 191
6 is pointed and seats within the coupling pocket 208 of the actuation valve pin member 210. The actuating valve pin member 210 has a reduced valve needle stem portion 2 at its opposite end.
12 and mounted within the valve housing bore 133 inwardly of the bellows 186.
6 and along its intermediate constant diameter section or length 214 for reciprocating movement in a sealed manner.

Valve body 218 includes a cylindrical land 2 press fit within open end 174 of bellows cover 170.
19 is formed, and this land has a bellows
It extends within the open end of the valve bellows cover sufficiently to provide an axially adjustable sealed joint operable to tightly calibrate the unit. In addition, a conical compression coil spring 220 is concentrically positioned between the bellows end member 190 and the outer end of the valve body 218.
6 in seated engagement with the bellows cover 170. With such an arrangement, the bellows output rod and the actuating valve pin member 206 are in one position by forcing the output rod 191 into automatically aligned coupling of the valve pin pocket 208 in the actuating valve pin member 210. is moved in the axial direction.

Central valve body 218 has O-ring seals 226, 228, and 230, each received within an annular groove thereof and sealingly engaged with a respective valve body bore portion. Land portions 221, 222 and 224 of progressively smaller diameter formed on the valve body are hermetically received and positioned within progressively smaller diameter bore portions 138, 140 and 142. The O-ring 226 in the large diameter land portion 221 thus seals the bellows pressure control cell 192, which is open to suction pressure and closes to the smaller diameter adjacent valve body land 222.
In cooperation with the O-ring seal 228 in the opening, the annular chamber 232 is sealed in the bore portion 138 which is open indirectly through the mouth 148 to the crankcase via the ventilation passage provided by the present invention. The O-ring seal 228 also has an O-ring seal 230 at the smaller diameter adjacent valve body land 224.
In conjunction with the opening 162 to seal the annular chamber 234 extending in place of the spool valve body in the bore portion 140 which opens directly into the crankcase via the mouth 162. The valve body O-ring seal 230 also connects the discharge cavity 1 through the port 168 at the smallest diameter bore portion 142.
The closed end 136 of the valve body hole, which opens directly to 24, is sealed.

The valve body 218 has a central hole 21 passing through the middle portion.
6 counterbore 2 at its end closest to the bellows
36, the counterbore joins a larger counterbore 238 which is open to the bellows pressure control cell 192 and thus to the compressor suction. Counterbore 236 extends around actuation valve pin member portion 214 and defines an annular crankcase bleed or vent valve passage 240 connected to the crankcase according to chamber 232 by a pair of diametrically aligned radial ports 242. . Larger diameter counterbore 238
is open to the crankcase vent valve passage 240 and slidably supports an enlarged cylindrical head 244 formed at its bellows end on the actuation valve pin member 210. The enlarged valve pin member head 244 is operative to control crankcase ventilation and for that purpose includes a tapered step 246 where it joins the elongated cylindrical pin portion 214. There is. A tapered step 246 engages a conical valve seat 248 forming a step between valve body counterbores 236 and 238 to form a fourth
A valve face is provided which closes off the crankcase vent valve passage 240 as shown and described in detail below. Alternatively, the valve face 246 is connected to the valve seat 248.
First away from the crankcase vent valve passage 240
can be opened into the counterbore 238 and then, with a further slight movement, the valve head 244 opens the circular groove 249 in the counterbore 238. Groove 2
49 is also open to a pair of longitudinally extending passages 250 in the counterbore 238 which simultaneously direct such valve movement to the crankcase vent valve passage 240 to the bellows pressure control cell 192 and thus to the compressor. It is effective in connecting to the suction cavity 114.

A central bore 216 in the valve body 218 joins a larger diameter valve body bore 252 at its opposite end, which is closed at one end by a tapered step 253 extending from the actuation valve pin member portion 214 and closed at the other end. Case/charge valve main body member 2
54 is accepted. The crankcase charge valve body member 254 is press fit into the valve body bore 252 and extends on one side thereof and within the valve body, around the actuation valve pin member portion 214 and through a radial port 258 in the valve body. A cavity 256 is formed with respect to the outwardly located chamber 234 and thus with respect to the crankcase. The crankcase charge valve body member 254 also cooperates with the small diameter valve body portion 224 and its O-ring seal 230 to connect the compressor discharge cavity 124 with the closed end 135 of the valve housing bore through the radial port 168 of the valve housing. A chamber 260 is formed that is open to the air.

The crankcase charge valve body member 254 is formed with a bell-shaped valve cavity 262 that is exposed through an open end 264 to a discharge pressure connected chamber 260 and at the other end of the central crankcase charge valve. Valve port 266 is open to chamber 256 which receives smaller diameter stem portion 212 of actuating valve pin member 210 and which communicates with the crankcase. Mounted within the crankcase charge valve body member 254 within the cavity 262 is a crankcase charge valve having a large ball portion 268 and a small ball portion 270 that are welded together. and a large ball portion 268 is held against the end of the actuation valve pin member axle portion 212 and normally seats on a complementary shaped portion of the bell-shaped cavity 262 to close the crankcase charge valve port 266. It is biased by a shaped coil compression spring 272. Spring 272 is attached to valve body member 2 defining an opening 264 to the valve cavity at its opposite enlarged end.
54, and a screen 275 is mounted over the opening to allow foreign matter to pass through. The smaller end of the conical spring has a slightly smaller diameter than the smaller ball portion 270 to enable this spring end to be snapped into place to be captured between the two ball portions. ing. This is done so that the large ball valve element 268 fits sufficiently to ensure a sealing relationship between the valve seat and the refrigerant gas at the discharge pressure when the valve is in its closed position as shown in the third figure. so that ball valve element 268 remains aligned during valve opening movement to the fully open position of FIG. This facilitates free movement of integral ball valve elements 268, 270 relative to spring 272.

Crankcase venting by closing valve element 268 on crankcase charge valve port 266 and simultaneously acting on actuating valve pin member 210 via valve elements 268, 270 to bring its vent valve end 244 into an open position. In addition to the spring biasing force that acts to open the valve port 240, the movable crankcase
Gas exhaust pressure activation is accomplished by exhaust pressure within cavity 260 acting on the unbalanced upstream sides of charge valve elements 268, 270. This discharge pressure biasing at the crankcase charge end of the control valve arrangement causes the discharge pressure to charge the crankcase to achieve a reduced compressor displacement as detailed below.
In addition to being made available by 68,270 through the opening of crankcase charge valve port 266, increasing exhaust pressure is also used to lower the compressor displacement control point.

The large ball valve portion 268 is the actuating valve pin member 2
suction pressure acting through 10 and expansion of spring-loaded bellows 186 to open crankcase charge valve port 266 away from its valve seat against the force of spring 272 and variable discharge pressure biasing. However, the operating valve pin member 210
simultaneously acts on its valve head 244 to close the crankcase bleed valve orifice 240. In turn, these crankcase charge and crankcase vent valve actuations are reversed by suction pressure-energized contraction of bellows 186 assisted by exhaust pressure activation in crankcase charge valve 268 .

Referring now to the operation of the variable displacement compressor control valve arrangement 130 in the system, gaseous refrigerant exiting the accumulator 18 at low pressure enters the compressor suction cavity 114, is discharged to the compressor discharge cavity 124, and is then discharged to the compressor discharge cavity 124. It is discharged to the capacitor 12 at a certain rate depending on the wobble plate angle of the compressor. At the same time, the gaseous refrigerant at the suction pressure is transmitted to the bellows cell 192 in the compressor and acts on the deaerated bellows 186, which expands in response to the decrease in suction pressure and acts on the actuating valve pin. A force is applied on bellows output rod 191 to urge movement of member 210 toward the fourth illustrated position, closing crankcase vent valve 240 and simultaneously opening crankcase charge valve 266. On the other hand, the gaseous refrigerant discharge pressure in the compressor is simultaneously transmitted to the valve chamber 260 and acts on the ball valve devices 268, 270 against the expansion of the bellows, thereby closing the crankcase charge valve port 266 as shown in FIG. At the same time, the crankcase vent valve 240 is encouraged to open. These variable pressure biases normally cause maximum compressor pumping by closing crankcase charge valve port 266 and simultaneously opening crankcase vent valve port 240 to establish zero crankcase suction pressure differential. This is in addition to the spring bias that normally acts to adjust the control valve system 130. The purpose is to keep the evaporator 16 just above freezing temperature (pressure) without cycling the compressor on and off with the clutch 36, and as much as can be achieved at higher ambient temperatures without evaporator freezing. Air conditioning the compressor displacement under all conditions to achieve the optimum of maintaining a cool evaporator and maintaining as high an evaporator temperature as can be maintained while still providing some dehumidification at lower ambient temperatures. The goal is to meet the requirements. For this purpose, the control point for the control valve arrangement 130 that determines the displacement change is determined such that when the air conditioning capacity demand is high, the suction pressure at the compressor after the pressure drop from the evaporator 16 is at the control point (e.g. 170 ~ 210kPa). The control valve traverse 130 closes the crankcase charge valve port 266 and closes the crankcase vent valve when the then existing discharge-suction pressure differential acting on the control valve system is high enough to maintain it in the condition shown in FIG. The bellows 186 is removed during assembly to open the opening 240.
calibrated at and with spring bias. The control valve device 130 maintains air bleed or ventilation from the crankcase to the suction section while simultaneously cutting off the discharge pressure to the crankcase so that a difference in suction pressure does not occur, and as a result, the wobble plate 5
0 remains in its maximum angular position, shown in solid line in FIG. 1, to provide maximum compressor displacement. Then, as the air conditioning capacity demand decreases and the suction pressure reaches the control point, the associated control valve arrangement 130
Changes in the exhaust-suction pressure differential acting on the valve adjust the valves to open the crankcase charge valve port 266 and simultaneously close the crankcase bleed port 240, thereby increasing the crankcase suction pressure differential. Since the angle of the wobble plate 50 is controlled by the force balance on the piston 44, only a slight increase in crankcase suction pressure (e.g. 40-100 kPa) will cause the wobble plate axis to decrease, reducing the wobble plate angle and therefore the compressor displacement. It is effective to generate a net force on the piston that induces a moment around it. Moreover, in addition to being acted upon by the suction control pressure, the control valve bellows 186 must also overcome the discharge pressure when expanding to increase the crankcase suction pressure differential and reduce the compressor displacement. At , the displacement change control point decreases with increasing exhaust pressure (higher ambient temperature). Refrigerant flow rate, and suction pressure drop increases as discharge pressure (higher ambient temperature)
The control valve decreases the control point in proportion to the discharge pressure and similarly decreases the suction line pressure drop in that it increases with the discharge pressure. This compressor displacement compensation feature allows control at the compressor suction while maintaining a nearly constant evaporator pressure (temperature) above the freezing point, which results in reduced power consumption and substantial It has been found that this results in better high-load performance.

In the above type of compressor, the lubrication is provided as in some other reciprocating piston type compressors and engines which provide ventilation from the crankcase to the suction section but do not include the lubrication and ventilation arrangement of the present invention. Most, if not all, of the oil added to the crankcase is evacuated from the cylinder due to venting to the suction along with the gases therein. On the other hand, some of the expelled oil is returned to the crankcase via the piston rings scraping against the cylinder walls and/or operating pressure differentials blowing the oil over the piston rings. According to the invention, ports and passages 148, 15
0,152,154,156,158 and 160
The lubrication and ventilation passage means formed by the rotating bearing surface of the wobble plate 50, that is, the thrust needle bearing 7
0 and a journal 66 supporting the wobble plate at its inner diameter 64 to the compressor suction cavity 114 of the crankcase 24.
Determine the route for ventilation. The arrows shown in FIGS. 1 and 2 depict the circulation of the refrigerant within the compressor, and in this circulation, the entrained oil also flows between the two radial needle bearings 28 and 30 of the drive shaft and the variable angle within the crankcase. It can be used to lubricate the friction or sliding surface of the wobble plate mechanism. The ventilation passage thus provided carries the pressurized gaseous refrigerant with its accompanying oil through the wobble plate's rolling bearing or thrust needle bearing 70 and also along the drive plate journal 66 at the inner diameter 64 of the wobble plate 50. The compressor suction cavity 114 of the wobble plate pivot in one pivot pin allows the flow to flow radially inwardly over or over one pivot pin.
160 to ensure lubrication of these critical rotating bearing surfaces. Moreover, the entrained oil is separated by centrifugal action on the surfaces of these rotating bearings and returned to the crankcase for further compressor lubrication. As a result, even with such venting, the amount of oil actually delivered to the compressor suction cavity and available for discharge from the compressor to the refrigerant circuit in the discharge cavity is substantially reduced, so that no oil is returned to the crankcase by centrifugal action. Some amount of this is retained therein and always available for further lubrication of the compressor mechanism, especially its critical bearing surfaces. This ensures that at all compressor operating conditions some amount of oil is retained within the crankcase for lubrication of the mechanism's critical bearing surfaces. Additionally, the amount of oil allowed to circulate within the cooling system external to the compressor is minimized, resulting in substantially improved air conditioning performance.

[Brief explanation of the drawing]

FIG. 1 is a sectional view, partially in elevation, of a refrigerant compressor according to the present invention, which is a variable angle wobble plate type compressor incorporating a preferred embodiment of the passive lubrication system according to the present invention; FIG. 2 is a fragmentary enlarged sectional view taken along line 2-2 of FIG. 1 in the direction of the arrow;
FIG. 3 is a fragmentary enlarged sectional view of the displacement control valve device shown in FIG. 1 as a whole, viewed in the direction of the arrow, and FIG. 4 shows some parts of the displacement control valve device shown in FIG. 3. FIG. [Description of symbols of main parts], 10... Refrigerant compressor, 50... Wobble plate, 66... Journal, 70... Thrust needle bearing, 74... Pivot pin, 114... Suction cavity, 124... Discharge cavity ,
129...Crankcase, 148...Head 2
Radial port of 2, 150...Port of valve plate 108, 1
52, 154... passage in cylinder block 20, 156, 158... central axial passage and intersecting radial passage in drive shaft 26, 160... central axial passage in drive plate pivot pin 74.

Claims (1)

Claims: 1 Suction and exhaust cavities 114 and 124 such that a gaseous refrigerant, together with an accompanying lubricant, enters the crankcase from the exhaust cavity 124 under pressure and is vented into the suction cavity 114. In a refrigerant compressor having a crankcase 129 containing the compressor mechanism, a passive lubrication system transfers crankcase 129 pressure to the suction cavity 114 between the rotating shaft surfaces 66, 70 of the compressor mechanism.
lubrication and ventilation passageway for venting to the shaft surface with entrained lubricant and centrifugally separating some of the entrained lubricant at the bearing surface and returning it to the crankcase for further compressor lubricant use; having means 148 to 160;
This substantially reduces the amount of lubricant that is actually delivered from the crankcase into the compressor suction cavity and available for evacuation from the compressor in the discharge cavity, and eliminates the amount of lubricant that is returned to the crankcase by said centrifugal action. A refrigerant compressor, characterized in that a lubricant is retained therein and always available for further compressor lubrication. 2. In the compressor according to claim 1, the compressor mechanism includes a variable angle wobble plate 50 mounted via a rolling thrust bearing 70 and a journal bearing 66, and the lubrication and ventilation passage means 148 to 160 are connected to a crankshaft. A refrigerant compressor characterized in that the refrigerant compressor is arranged to vent case 129 pressure to the suction cavity 114 through the bearing. 3. In the compressor according to claim 2, the lubrication and ventilation passage means 148 to 160
A refrigerant compressor comprising a passageway 160 in the pivot shaft 74 forming a mounting for the variable angle wobble plate 50.