Refrigerant Compressor

Abstract

In order to operate as energy-efficiently as possible a refrigerant compressor, comprising a reciprocating piston compressor and an electric motor, an overall housing having a motor housing portion for the electric motor and a compressor housing portion for the reciprocating piston compressor, a suction connector connected to a low-pressure side of the reciprocating piston compressor, a pressure connector connected to a high-pressure side of the reciprocating piston compressor, wherein provided in the compressor housing portion is at least one cylinder of the reciprocating piston compressor, which has a piston that is movable in a cylinder bore formed in the compressor housing portion, a valve plate closing the cylinder bore, and a cylinder head that spans the valve plate and forms part of the compressor housing portion, it is proposed that a mechanical performance control unit should be provided by which the low-pressure side and the high-pressure side are connectable to one another for the purpose of reducing performance, and that there should be provided in the region of the cylinder head a nonreturn valve that is held against the cylinder head and that allows a refrigerant stream exiting therefrom on the high-pressure side and blocks a refrigerant stream counter to this refrigerant stream.

Claims

1. A refrigerant compressor, comprising a reciprocating piston compressor and an electric motor, an overall housing having a motor housing portion for the electric motor and a compressor housing portion for the reciprocating piston compressor, a suction connector connected to a low-pressure side of the reciprocating piston compressor, and a pressure connector connected to a high-pressure side of the reciprocating piston compressor, wherein provided in the compressor housing portion is at least one cylinder of the reciprocating piston compressor, which has a piston that is movable in a cylinder bore formed in the compressor housing portion, and a valve plate closing the cylinder bore, and a cylinder head that spans the valve plate and forms part of the compressor housing portion, wherein a mechanical performance control unit is provided by which the low-pressure side and the high-pressure side are connectable to one another for the purpose of reducing performance, and wherein provided in the region of the cylinder head is a nonreturn valve that is held against the cylinder head and that allows a refrigerant stream exiting therefrom and blocks a refrigerant stream counter to this exiting refrigerant stream.

2. The refrigerant compressor as claimed in claim 1, wherein the nonreturn valve is arranged downstream of the outlet chamber and prevents backflow of refrigerant downstream of the nonreturn valve into the outlet chamber.

3. The refrigerant compressor as claimed in claim 1, wherein the nonreturn valve is arranged on the cylinder head at a spacing from the valve plate.

4. The refrigerant compressor as claimed in claim 1, wherein the nonreturn valve is arranged at a region of the cylinder head remote from the valve plate.

5. The refrigerant compressor as claimed in claim 1, wherein the nonreturn valve is arranged in the region of a transition from the outlet chamber into an outlet refrigerant path.

6. The refrigerant compressor as claimed in claim 1, wherein the nonreturn valve is arranged and fixed in a receptacle that is arranged on the cylinder head.

7. The refrigerant compressor as claimed in claim 1, wherein the receptacle is integrally formed on the cylinder head.

8. The refrigerant compressor as claimed in claim 1, wherein the nonreturn valve is arranged sealed tight to the receptacle.

9. The refrigerant compressor as claimed in claim 1, wherein the nonreturn valve has a valve body with at least one through opening in it, and wherein the through opening is closable by a reed valve that is movable in relation to the valve body.

10. The refrigerant compressor as claimed in claim 9, wherein the reed valve is resiliently urged in the direction of a flow-blocking position in which the reed valve abuts against a sealing face of the valve body.

11. The refrigerant compressor as claimed in claim 9, wherein the reed valve is guided such that it is movable in relation to the valve body.

12. The refrigerant compressor as claimed in claim 11, wherein the reed valve as a whole is at a spacing from the valve body in a cleared-for-flow position.

13. The refrigerant compressor as claimed in claim 9, wherein the nonreturn valve has a capturing body for the reed valve, which positions the reed valve in its cleared-for-flow position.

14. The refrigerant compressor as claimed in claim 9, wherein the valve body takes the form of an annular body.

15. The refrigerant compressor as claimed in claim 14, wherein the valve body has at least one through opening which is arranged in an annular region around a center axis.

16. The refrigerant compressor as claimed in claim 15, wherein the reed valve takes the form of an annular body.

17. The refrigerant compressor as claimed in claim 16, wherein, in the cleared-for-flow position of the reed valve, refrigerant flowing through the through openings flows around the reed valve both in the region of its internal edge and also in the region of its external edge.

18. The refrigerant compressor as claimed in claim 1, wherein the mechanical performance control unit is arranged on the at least one cylinder head, in particular wherein the mechanical performance control unit is at least partly integrated into the at least one cylinder head.

19. The refrigerant compressor as claimed in claim 1, wherein, for the purpose of reducing performance, the mechanical performance control unit connects an outlet chamber in the cylinder head to an inlet chamber in the cylinder head by way of a controllable connection channel, in particular wherein the connection channel is arranged integrated into the cylinder head.

20. The refrigerant compressor as claimed in claim 1, wherein an outlet chamber in the cylinder head is arranged directly adjoining at least one outlet opening for the respective cylinder in the valve plate.

21. The refrigerant compressor as claimed in claim 1, wherein an inlet chamber in the cylinder head is arranged directly adjoining an inlet opening for the respective cylinder of the valve plate.

22. The refrigerant compressor as claimed in claim 1, wherein the mechanical performance control unit has a closing piston for the purpose of closing the connection channel, in particular wherein, for the purpose of closing the connection channel, the closing piston is settable on a sealing seat that runs in a manner surrounding the connection channel, in particular wherein a sealing region of the closing piston is made from a metal with lower hardness than a metal from which the sealing seat is made, or vice versa, in particular wherein the sealing seat is arranged in a wall portion of the cylinder head that separates the inlet chamber from the outlet chamber, in particular wherein the sealing seat is arranged in a wall portion running above the valve plate and above the inlet chamber, in particular wherein the sealing seat is arranged on an opposite side of the inlet chamber to the valve plate.

23. The refrigerant compressor as claimed in claim 1, wherein a cylinder head has an inlet chamber and an outlet chamber for a cylinder bank that comprises at least two cylinders.

24. The refrigerant compressor as claimed in claim 1, wherein the respective mechanical performance control unit is associated with a cylinder bank.

25. The refrigerant compressor as claimed in claim 1, wherein, in the case of the refrigerant compressor having N cylinder banks, a mechanical performance control unit is associated with at least N1 cylinder banks.

26. The refrigerant compressor as claimed in claim 23, wherein a mechanical performance control unit is associated with each cylinder bank.

27. The refrigerant compressor as claimed in claim 22, wherein the closing piston is urged by a pressure spring in the direction of the position in which it cooperates with the sealing seat.

28. The refrigerant compressor as claimed in claim 22, wherein the closing piston is actuable by a pressure chamber which, depending on the external control of the performance control unit, is configured to be acted upon either by negative pressure or by high pressure.

29. The refrigerant compressor as claimed in claim 1, wherein a control unit comprised within the performance control unit is provided, by which the action of pressure upon the closing piston is controllable.

30. The refrigerant compressor as claimed in claim 1, wherein there is provided a performance controller that controls the at least one performance control unit in accordance with a demanded compressor conveying performance.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0151] FIG. 1 shows a side view of an exemplary embodiment of a refrigerant compressor according to the invention;

[0152] FIG. 2 shows a plan view, in the direction of the arrow A in FIG. 1, of the refrigerant compressor according to the invention;

[0153] FIG. 3 shows a front view of the exemplary embodiment of the refrigerant compressor according to the invention;

[0154] FIG. 4 shows a section along the line 4-4 in FIG. 2, with one half offset;

[0155] FIG. 5 shows a longitudinal section, along the line 5-5 in FIG. 2, through the refrigerant compressor according to the invention;

[0156] FIG. 6 shows a section along the line 6-6 in FIG. 7;

[0157] FIG. 7 shows a section through a first exemplary embodiment of a cylinder head according to the invention, along the line 7-7 in FIG. 6;

[0158] FIG. 8 shows an enlarged illustration of a nonreturn valve according to the invention in the closed position;

[0159] FIG. 9 shows an illustration similar to FIG. 8, of the nonreturn valve according to the invention in the open position;

[0160] FIG. 10 shows an illustration similar to FIG. 7, of a second exemplary embodiment of a cylinder head according to the invention;

[0161] FIG. 11 shows an illustration similar to FIG. 7, of a third exemplary embodiment of a cylinder head according to the invention; and

[0162] FIG. 12 shows an illustration similar to FIG. 7, of a fourth exemplary embodiment of a cylinder head according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0163] One exemplary embodiment of a refrigerant compressor according to the invention, illustrated in FIGS. 1 to 5, comprises an overall housing 10 in which there are arranged a reciprocating piston compressor 12, in particular a compressor with pistons that are movable by a shaft axis, and an electric motor 14.

[0164] Preferably, the overall housing 10 comprises a compressor housing portion 22, which is an external housing of the reciprocating piston compressor 12, and a motor housing portion 24, which is an external housing of the electric motor 14.

[0165] The overall housing 10 is preferably formed by a one-piece housing body 26 which extends in a direction parallel to a center axis 28, explained in detail below, and is closed at the end on the compressor housing portion 22 side by a bearing cap 32 and is closed at the end in the region of the motor portion 24 by an end cover 34.

[0166] A compressor shaft, designated 42 as a whole, extends in the compressor housing portion 22, coaxially relative to the center axis 28, between a first shaft bearing 44 arranged on the bearing cap 32 and a second shaft bearing 46 that is arranged between the reciprocating piston compressor 12 and the electric motor 14, wherein the second shaft bearing 46 is held against a center wall 48, which is made in the housing body 26 and delimits a drive compartment 52, wherein the drive compartment 52 is located between the bearing cap 32 and the center wall 48, the compressor shaft 42 extends through it, and eccentrics 54 and 56 of the compressor shaft 42 are arranged therein, wherein arranged on each of the eccentrics 54 and 56 are respectively a connecting rod 62.sub.1 and 62.sub.2 each having a connecting rod arm, and two connecting rods 64.sub.1 and 64.sub.2 each having a connecting rod arm, wherein the connecting rod arms of the connecting rods 62.sub.1 and 64.sub.1 drive the pistons 66.sub.1 and 68.sub.1, and the connecting rod arms of the connecting rods 62.sub.2 and 64.sub.2 drive the pistons 66.sub.2 and 68.sub.2.

[0167] The pistons 66 and 68, which in particular in the case of the compressor are driven and movable radially relative to the compressor shaft 42, are guided in cylinder bores 72 and 74 that are formed by cylinder housings 76, 78 that are made in the compressor housing portion 22 and are in particular made in one piece therewith.

[0168] Each cylinder housing 76, 78, together with the cylinder bore 72, 74 and the piston 66, 68 guided therein, forms a respective cylinder 82, 84.

[0169] The two first cylinders 82.sub.1 and 84.sub.1 that are made in the compressor housing portion 22 form a first cylinder bank 86.sub.1, while the two cylinders 82.sub.2 and 84.sub.2 that are formed in the compressor housing portion 22 form a second cylinder bank 86.sub.2.

[0170] In each of the cylinder banks 86.sub.1 and 86.sub.2, the respective cylinder bores 72.sub.1 and 74.sub.1, and 72.sub.2 and 74.sub.2, are closed by a common valve plate 88.sub.1 and 88.sub.2, which with the aid of a gasket 89 lies on the respective cylinder housings 76.sub.1 and 78.sub.1, and 76.sub.2 and 78.sub.2, such that it is sealed tight, and thus delimit compression chambers that are surrounded by the respective valve plate 88.sub.1 and 88.sub.2 respectively and the respective piston 66.sub.1 and 68.sub.1, or 66.sub.2 and 68.sub.2, and the cylinder bores 72.sub.1 and 74.sub.1 or 72.sub.2 and 74.sub.2.

[0171] For their part, the valve plates 88.sub.1 and 88.sub.2 are then in turn covered by cylinder heads 92.sub.1 and 92.sub.2 respectively, wherein the open sides 93.sub.1, 93.sub.2 of the respective cylinder heads 92.sub.1 and 92.sub.2 face the valve plates 88.sub.1 and 88.sub.2 and lie on the valve plates 88.sub.1 and 88.sub.2 such that they are sealed tight.

[0172] As illustrated in FIGS. 6 and 7, in each of the cylinder heads 92.sub.1 and 92.sub.2 there is arranged respectively an inlet chamber 94, comprised within a low-pressure side of the reciprocating piston compressor 12, and an outlet chamber 96, comprised within a high-pressure side of the reciprocating piston compressor 12, and these are associated with the two cylinders 82 and 84 of the respective cylinder bank 86.

[0173] In particular, the inlet chamber 94 lies above inlet openings 102 and 104 of the cylinder 82, which are made in the respective valve plate 88, and inlet openings 106 and 108 of the cylinder 84 of the respective cylinder bank 86, for example the cylinder bank 86.sub.2, and directly adjoins the valve plate 88.

[0174] Further, the outlet chamber 96 lies above outlet openings 112 and 114 of the cylinder 82, which are made in the respective valve plate 88, and outlet openings 116 and 118 of the cylinder 84, which are provided with outlet valves 113, 115, 117, 119 seated on the valve plate 88, and directly adjoins the valve plate 88.

[0175] As illustrated in FIGS. 6 and 7, each cylinder head 92 comprises an external body 122 which is supported on the respective valve plate 88 by way of a sealing layer 123 and spans this and surrounds the inlet chamber 94 and the outlet chamber 96, which for their part are in turn separated from one another by a separating body 124 that runs within the external body 122 and is connected thereto, wherein the external body 122 and the separating body 124 extend upward from the respective valve plate 88 and extend over and span the inlet chamber 94 and the outlet chamber 96.

[0176] Thus, the outlet chamber 96 lies laterally next to the inlet chamber 94 in the region of the valve plate 88, and extends between the external body 122 and the separating body 124, at least in certain regions also above the inlet chamber 94.

[0177] For the purpose of controlling performance, that is to say controlling the compressor conveying performance, of the refrigerant compressor, associated with each cylinder head 92 there may be a mechanical performance control unit 142 that is actively controlled by a performance controller 138 and by which a connection channel 144 between the outlet chamber 96 and the inlet chamber 94 may be closed or opened, wherein when the connection channel 144 is closed (FIG. 7) the respective cylinders 82, 84 associated with the cylinder head 92 compress refrigerant at full performance, and when the connection channel 144 is open they do not compress refrigerant, since the refrigerant flows back from the outlet chamber 96 and into the inlet chamber 94 through the connection channel 144.

[0178] Here, a portion 144a of the connection channel 144 runs through an insert part 146 which is inserted into the separating body 124, which forms a sealing seat 148 facing the outlet chamber 96, and which adjoins a part of the outlet chamber 96 that surrounds the sealing seat 148 and adjoins it.

[0179] Further, the sealing seat 148 faces a closing piston 152 which is configured to be set on the sealing seat 148, for example by a sealing region 154 made of metal, in order to close the connection channel 144 in a manner that seals tight, and which is configured to be raised away from the sealing seat 148 far enough for the sealing region 154 to be at a spacing from the sealing seat 148 and thus for refrigerant to be able to flow over from the outlet chamber 96 through the portion 144b and into the inlet chamber 94 through the portion 144a.

[0180] Preferably in this case, the closing piston 152 is guided coaxially relative to the insert part 146 having the sealing seat 148 and, sealed by a piston ring 153, in a guide bore 156 that is formed by a guiding bushing body 158 of the cylinder head 92 which is integrally formed on the external body 122.

[0181] Preferably, the closing piston 152 itself or at least the sealing region 154 is made from a metal, for example a non-ferrous metal, of lower hardness than the metal of the sealing seat 148, which is made for example from steel, in particular hardened steel.

[0182] In order to enable rapid movement of the closing piston 152, in particular a stroke of the closing piston 152 between a closed position (FIG. 7) and an open position, indicated in dashed lines in FIG. 7, is in the range between a quarter and a half of an average diameter of the connecting channel 144.

[0183] Here, the closing piston 152 delimits a pressure chamber 162, which is arranged on a side of the closing piston 152 remote from the sealing region 154 and is closed by a terminating body 164 on an opposite side to the closing piston 152.

[0184] The volume of the pressure chamber 162 is in particular so small that in the open position of the closing piston it is smaller than a third, preferably smaller than a quarter, more preferably smaller than a fifth, advantageously smaller than a sixth and even more advantageously smaller than an eighth of the maximum volume of the pressure chamber 162 in the closed position of the closing piston 152.

[0185] Further, arranged in the pressure chamber 162 is a pressure spring 166 that on one side is supported against the terminating body 164 and on the other urges the closing piston 152 in the direction of its closed position seated on the sealing seat 148.

[0186] Depending on the pressurized urging of the pressure chamber 162, the closing piston 152 is movable into its open position, illustrated in dashed lines in FIG. 7, or into its closed position, illustrated in FIG. 7.

[0187] For this purpose, a throttle channel 172 passes through the closing piston 152 and extends from the pressure chamber 162 through the closing piston 152 to an outlet opening 157 that is arranged radially outside the sealing region 154 on a side facing the sealing seat 148, but, because it lies radially outside the sealing element 154, in the closed position of the closing piston 152 it allows entry to refrigerant that is under pressure in the outlet chamber 96 and that flows around the sealing seat, and supplies it to the pressure chamber 162 in a throttled arrangement.

[0188] Moreover, a relief channel 176 leads into the pressure chamber 162, for example through the terminating body 164, and is configured to be connected by a solenoid valve, designated 182 as a whole, to a pressure relief channel 184 connected to the inlet chamber 94.

[0189] For example, the solenoid valve 182 takes a form such that it has a valve body 186 by which the connection between the pressure relief channel 184 and the relief channel 176 can be made or broken.

[0190] If the connection between the relief channel 176 and the pressure relief channel 184 is made, negative pressure dominates in the pressure chamber 162, while the closing piston 152 is acted upon by the pressure in the outlet chamber 96 on its side facing the outlet chamber 96 and is thus moved into its open position.

[0191] However, if the connection between the pressure relief channel 184 and the relief channel 176 is broken by the valve body 186, the pressure spring 166 presses the closing piston 152 onto the sealing seat 148, and in addition high pressure flows into the pressure chamber 162 through the throttle channel 172, with the result that in the pressure chamber 162 high pressure builds up and, in addition to the action of the pressure spring 166, presses the closing piston 152 onto the sealing seat 148 with the sealing element 154.

[0192] In particular, the closing piston 152 takes a form such that it extends radially beyond the sealing seat 148, such that even when the closing piston 152 is in the closed position the piston face that is radially outside the sealing seat 148 and is acted upon by high pressure results in the closing piston 152 being moved in opposition to the force of the pressure spring 166 and into the open position, illustrated in dashed lines in FIG. 7, provided the valve body 186 of the solenoid valve 182 makes the connection between the relief channel 176 and the pressure relief channel 184, which has the result that a negative pressure is established in the pressure chamber 162.

[0193] Refrigerant under negative pressure is supplied by way of a supply channel 202 (FIG. 5) that is made in the compressor housing portion 22, is comprised within the low-pressure side of the reciprocating piston compressor 12, and leads to an inlet opening 204 (FIG. 7) leading to the valve plate 88, wherein refrigerant under negative pressure flows through the inlet opening 204 to a passage opening 206 in the valve plate 88 and passes through this into the inlet chamber 94.

[0194] Moreover, as illustrated in FIG. 7, an outlet channel 210 that is made in the cylinder head 92 and comprised within the high-pressure side of the reciprocating piston compressor 12 leads from the outlet chamber 96 to an outlet opening 212 in the valve plate 88, through which the pressurized refrigerant in the outlet chamber 96 passes into an outlet channel 214 provided in the compressor housing portion 22 and can flow to a pressure connector 216.

[0195] Provided at the transition from the outlet chamber 96 to the outlet channel 210 is a nonreturn valve, designated 220 as a whole, which, as illustrated on a larger scale in FIGS. 8 and 9, has a valve body 222 which takes the form for example of an annular body and has through openings 226 that are arranged successively in an annular region around a center axis 224 and pass through the valve body 222 from an inflow side 228 to an outflow side 232.

[0196] A reed valve 234, likewise taking the form of an annular body, is provided such that it is movable in relation to the valve body 222 and, for the purpose of closing the through openings 226, is configured to abut against the outflow side 232 of the valve body 222 in a manner that seals tight and, for the purpose of clearing the through openings 226, is configured to move as a whole away from the outflow side 232 and to be positioned at a spacing therefrom.

[0197] This position of the reed valve 234, blocking flow 226 through the nonreturn valve 220 from the outflow side 232 in the direction of the inflow side 228, is brought about by a spring element 236 which likewise takes the form of an annular body and is supported on the one hand on an opposite side of the reed valve 234 to the outflow side 232 and on the other hand against a capturing body 242 of the nonreturn valve 220, wherein the capturing body 242 is held at a spacing from the outflow side 232, for example at a center region 244 of the valve body 222 that lies between the through openings 226 and the center axis 224, this center region 244 running around the center axis 224 and on the inside of the through openings 226.

[0198] Preferably, anchored in the center region 244 is a holding pin 246 which passes through central openings in both the reed valve 234 and also the spring element 236 and extends as far as the capturing body 242 and is firmly connected thereto, with the result that the holding pin 246 fixes the capturing body 242 such that it is undisplaceable in the direction of the center axis 224 in relation to the valve body 222, to prevent movements in the direction of the center axis 224.

[0199] In the position illustrated in FIG. 9, which is open to the maximum, the reed valve 234, which has been moved as a whole away from the outflow side 232, enables flow through each of the respective through openings 226 from the inflow side 228 in the direction of the outflow side 232, wherein the flow then exits on the outflow side 232, from the respective through opening 226, and in relation to the center axis 224 flows radially outward and radially inward in the direction of the holding pin 246, in order to flow past both an internal edge 252 and an external edge 254 of the reed valve 234, and past an outer side of the spring element 236 and the capturing body 242 and through openings 248 made in the capturing body 242 around the holding pin 246.

[0200] Preferably, the valve body 222 takes the form of an annular bodythat is to say is rotationally symmetrical in relation to the center axis 224and has a circle-cylindrical outer face 255 by which it is inserted in a receptacle 258 formed at the transition from the outlet chamber 96 to the outlet channel 210, and is fixed for example on the one side thereof by a flange 256 that is provided and on the other by a securing ring 257, and in so doing terminates at the receptacle 258 and tight therewith.

[0201] As an alternative thereto, the outer face 255 may be provided with a thread and be screwed into a thread in the receptacle 258.

[0202] When a pressure lower than high pressure prevails in the outlet chamber 96, for example when there is a drop in pressure brought about by the performance controller 138 using the performance control unit 142, the reed valve 234 closes the through openings 226 as a result of the action of the spring element 236, with the result that pressure is maintained in the outlet channel 210, and a pressure equalization between the outlet chamber 96 and the inlet chamber 94 as a result of the action of the mechanical performance control unit 142 does not have an effect on the pressure in the outlet channel 210.

[0203] Thus, as a result of arranging the nonreturn valve 220 in the respective cylinder head 92, it is possible, in a simple manner, to convert a conventional compressorfor example one without performance controlinto a cylinder head 92 with controllable performance by substituting the cylinder head 92 with the performance control unit 142 and the nonreturn valve 220, without the need for any changes in the construction of the respective valve plate 88 and the respective cylinder bank 86.

[0204] In a second exemplary embodiment of a refrigerant compressor according to the invention with a second exemplary embodiment of a cylinder head 92 according to the invention, the elements that are identical to those of the first exemplary embodiment are provided with the same reference numerals, so reference can be made to the statements regarding the first exemplary embodiment in their entirety.

[0205] Unlike the first exemplary embodiment, the outlet channel 210 in the cylinder head 92 takes a form such that it leads directly to a pressure connector 260 that is provided on the cylinder head 92 and that is guided, for example from an opposite side to the valve plate 88, to the external body 122 and is directly connected thereto, with the result that the outlet channel 210 merges directly into a pressure conduit of the pressure connector 260.

[0206] In this case, the receptacle 258 for the valve body 222 is provided in the cylinder head 92 in a receiving body 262 that projects into the outlet chamber 96 from an opposite side to the valve plate 88, wherein the receiving body 262 is preferably likewise integrally formed in one piece with the external body 122 of the cylinder head 92.

[0207] In a third exemplary embodiment of a refrigerant compressor according to the invention with a third exemplary embodiment of a cylinder head 92, illustrated in FIG. 11, the nonreturn valve 220 is arranged such that the valve body 222 is seated in a receptacle 258 that is formed directly in an outer wall of the external body 122 of the cylinder head 92, with the result that there is absolutely no need for any additional measures for receiving the nonreturn valve 220 in the cylinder head 92, but all that needs to be done is to provide a passage in the outer wall of the external body 122, which forms the receptacle 258 for the valve body 222, wherein for example the valve body 222 is screwed into an internal thread of the receptacle 258 by an external thread.

[0208] In this case, the pressure connector 260 can be mounted on the external body 122 in a simple manner, with the result that the refrigerant passing through the nonreturn valve 220 can directly enter the pressure conduit of the pressure connector 260.

[0209] Otherwise, in the third exemplary embodiment, the elements that are identical to the above exemplary embodiments are provided with the same reference numerals, so for a description thereof reference can be made to the statements regarding the above exemplary embodiments in their entirety.

[0210] In a fourth exemplary embodiment of a refrigerant compressor according to the invention with a fourth exemplary embodiment of a cylinder head 92, the elements that are identical to those of the above exemplary embodiments are provided with the same reference numerals, so for a description thereof reference can be made to the statements regarding the above exemplary embodiments in their entirety.

[0211] Unlike the above exemplary embodiments, in the fourth exemplary embodiment it is provided for there to be made in the external body 122 of the cylinder head 92 a passage 264 from which refrigerant can directly enter the pressure connector 260, wherein the nonreturn valve 220 is inserted into a receptacle 258 that is arranged on the inlet side of the pressure connector 260, with the result that the pressure connector 260 itself forms the receptacle 258 for the valve body 222.

[0212] Here, for example the pressure connector 260 may be part of a blocking valve 266 mounted on the cylinder head 92.

[0213] Thus, in the fourth exemplary embodiment of the refrigerant compressor according to the invention, the nonreturn valve 220 is not received in the cylinder head 92 but held on the cylinder head 92 indirectly by way of the high-pressure connector 260.

[0214] The exemplary embodiments of the refrigerant compressors according to the invention take the form for example of semi-hermetic compressors, such that refrigerant under negative pressure is supplied to a motor compartment 274 by an inlet connector element 272 that is arranged on the end cover 34, and flows through the electric motor 14 in the direction of the center wall 48 and passes out of the motor compartment 274 through into the supply channel 202, with the result that the supplied refrigerant on the low-pressure side brings about cooling of the electric motor 14 in the motor compartment 274.

[0215] For its part, the electric motor 14 comprises a stator 282 that is held fixed in the motor housing portion 24 and has a stator winding 284.

[0216] The stator 282 further has a rotor 286, which comprises for example permanent magnets and is operable as a synchronous motor, and in addition a squirrel cage, so that it may start up as an asynchronous motor.