Pumping unit for feeding a cooling fluid and reciprocating machine comprising said pumping unit

Abstract

Pumping unit for feeding a cooling fluid into a reciprocating machine provided with an outer casing (2), an oscillating unit (3) arranged in the outer casing (2), and an elastic assembly (4), which elastically connects the oscillating unit (3) to the outer casing (2), the pumping unit (5) has a cooling circuit (23), which is formed inside the oscillating unit (3) and is designed to allow a cooling fluid to pass through the inside of the oscillating unit (3); and at least one reciprocating feed pump (24), which is arranged between the outer casing (2) and the oscillating unit (3) and is designed to damp the oscillations of the oscillating unit (3) with respect to the outer casing (2) and to feed the cooling fluid into the cooling circuit (23).

Description

[0001] Description

[0002] Title

[0003] Pumping unit for feeding a cooling fluid and reciprocating machine comprising said pumping unit of the patent for an industrial invention entitled:

[0004] “PUMPING UNIT FOR FEEDING A COOLING FLUID AND RECIPROCATING MACHINE COMPRISING SAID PUMPING UNIT” in the name of ROBERT BOSCH GMBH of German nationality with registered office at: POSTFACH 30 02 20

[0005] 70442 STUTTGART (GERMANY)

[0006] Inventors: CECERE Martino, PINTO Valerio, MAYER Robert, MEISIEK Achim

[0007] *** ***** ***

[0008] Technical sector

[0009] The present invention relates to a pumping unit for feeding a cooling fluid into a reciprocating machine, such as a reciprocating piston compressor.

[0010] Furthermore, the present invention relates to a reciprocating machine comprising said pumping unit.

[0011] Prior art

[0012] Known reciprocating machines comprise an outer casing, a cylinder coupled to the outer casing by a suspension system, a piston slidingly engaged inside the cylinder, and an actuating system to slide the piston inside the cylinder.

[0013] In particular, different types of reciprocating machines are known, such as reciprocating compressors, reciprocating pumps, or internal combustion engines. As an example, known reciprocating compressors comprise an elastic assembly, which elastically couples the piston to the cylinder, and an electric linear actuator, which is integral with the cylinder and is designed to slide the piston in a reciprocating manner inside the cylinder so as to selectively draw and compress gas. Since the linear actuator and the cylinder are elastically supported by the suspension system, the reciprocating sliding of the piston inside the cylinder causes the cylinder and the linear actuator to oscillate with respect to the outer casing in the sliding direction of the piston.

[0014] When the compressor is in use, the electric current powering the linear actuator, the friction caused by the sliding of the piston inside the cylinder, and the compression of the gas in the cylinder generate heat inside the compressor, and the internal components of the compressor therefore need to be cooled.

[0015] Generally, known compressors incorporate a cooling system comprising a cooling circuit, which has a series of channels formed inside the compressor to allow a cooling fluid to flow in the compressor, and a feed system to feed the cooling fluid into the cooling circuit.

[0016] Known feed systems comprise a cooling fluid, which is contained inside the outer casing and is in fluidic communication with an inlet and an outlet of the cooling circuit, and a reciprocating pump, which is arranged inside one of the channels of the cooling circuit and is actuated by the vibrations of the compressor in order to feed the cooling fluid from the external reservoir into the cooling circuit.

[0017] However, since the fuel pumps are built into the cooling circuit of the compressor and are only actuated by compressor vibrations, the fuel systems that are currently known are only able to feed limited amounts of cooling fluid.

[0018] Subject matter of the invention

[0019] One objective of the present invention is to provide a pumping unit for feeding a cooling fluid into a reciprocating machine that does not have the aforementioned drawbacks. The present invention provides a pumping unit for feeding a cooling fluid into a reciprocating machine, which comprises an outer casing, an oscillating unit arranged in the outer casing, and an elastic assembly, which elastically connects the oscillating unit to the outer casing, the pumping unit comprising:

[0020] - a cooling circuit, which is formed inside the oscillating unit and is designed to allow a cooling fluid to pass through the inside of the oscillating unit; and

[0021] - at least one reciprocating feed pump, which is arranged between the outer casing and the oscillating unit and is designed to damp the oscillations of the oscillating unit with respect to the outer casing and to feed the cooling fluid into the cooling circuit.

[0022] The present invention makes it possible to dissipate heat from the oscillating unit efficiently, while simultaneously damping the oscillations of the oscillating unit with respect to the outer casing.

[0023] In other words, the feed pump performs the dual function of feeding the cooling fluid into the cooling circuit and damping the oscillations of the oscillating unit with respect to the outer casing.

[0024] Furthermore, appropriately dimensioning the feed pump enables the viscous damping coefficient of the feed pump to be adjusted to ensure that the damping of the oscillations of the oscillating unit is appropriate to the particular operating conditions to which the reciprocating machine is subjected.

[0025] Another objective of the present invention is to provide a reciprocating machine that does not have the aforementioned drawbacks.

[0026] The present invention provides a reciprocating machine, preferably a piston machine, the reciprocating machine comprising:

[0027] - an outer casing;

[0028] - an oscillating unit arranged in the outer casing;

[0029] - an elastic assembly, which elastically connects the oscillating unit to the outer casing; and - a pumping unit as described above.

[0030] This allows the reciprocating machine to be cooled simply and efficiently, while simultaneously ensuring the appropriate dynamic behaviour of the reciprocating machine.

[0031] Short description of the figures

[0032] Further features and advantages of the present invention will become clearer from the description below of the non-limiting embodiments thereof, with reference to the figures in the attached drawings, in which:

[0033] - Figure 1 shows a reciprocating machine according to the present invention in cross section, with parts removed for clarity; and

[0034] - Figure 2 shows a detail of the reciprocating machine in Figure 1 in cross section, with parts removed for clarity.

[0035] Preferred embodiment of the invention

[0036] In Figure 1 , reference sign 1 denotes a reciprocating machine, preferably a piston machine, as a whole.

[0037] In the case described and illustrated here, which does not limit the present invention, the reciprocating machine 1 is a reciprocating compressor, which can be used in particular in a domestic appliance, such as a refrigerator, an air conditioning unit, or a heat pump.

[0038] The reciprocating machine 1 comprises an outer casing 2, an oscillating unit 3 arranged in the outer casing 2, an elastic assembly 4, which elastically connects the oscillating unit 3 to the outer casing 2, and a pumping unit 5.

[0039] In particular, the outer casing 2 has a base support 35 and delimits a closed chamber 6, inside which the oscillating unit 3, the elastic assembly 4, and the pumping unit 5 are arranged.

[0040] In more detail, the elastic assembly 4 forms a suspension system 7 comprising elastic elements 8 arranged between the outer casing 2 and the oscillating unit 3. In practice, the suspension system 7 elastically supports the oscillating unit 3, in particular in a substantially vertical direction.

[0041] In the case described and illustrated here, which does not limit the present invention, each elastic element 8 comprises a helical spring and is designed to be selectively compressed and extended as the distance between the outer casing 2 and the oscillating unit 3 varies. In particular, each elastic element 8 extends in a substantially vertical direction.

[0042] The oscillating unit 3 comprises an actuating assembly 9, which is connected to the outer casing 2 by the elastic assembly 4 and comprises a compression cylinder 10 extending along a central axis A1 and a linear actuator 11 ; a sliding assembly 12, which comprises a compression piston 13 engaged slidingly inside the compression cylinder 10; and elastic elements 14, which elastically connect the sliding assembly 12 to the actuating assembly 9.

[0043] In particular, the linear actuator 11 is designed to slide the sliding assembly 12 in a reciprocating manner with respect to the actuating assembly 9 along the central axis A1 .

[0044] In more detail, the linear actuator 11 is electric, and in particular comprises a stationary portion 15 and a movable portion 16, which is provided with permanent magnets and is coupled slidingly to the stationary portion 15 along the central axis A1.

[0045] The stationary portion 15 is integrally coupled to the compression cylinder 10, is annular, and extends around the central axis A1 . Furthermore, the stationary portion 15 is provided with an annular sliding seat 17. The movable portion 16 is annular and is engaged slidingly inside the sliding seat 17.

[0046] According to the present invention, the linear actuator 11 is designed to control the reciprocating sliding of the compression piston 13 inside the compression cylinder 10 so as to selectively draw gas into the compression cylinder 10 and compress said gas inside the compression cylinder 10. In practice, said reciprocating sliding of the compression piston 13 comprises an intake stroke, in which the gas is drawn into the compression cylinder 10, and a compression stroke, in which the compression piston 13 compresses the drawn gas inside the compression cylinder 10.

[0047] In the case described and illustrated here, the actuating assembly 9 comprises a support element 18, which is integrally coupled to the stationary portion 15 of the linear actuator 11 and is interposed between the linear actuator 11 and the elastic assembly 4; and a connecting frame 19, which integrally connects the stationary portion 15 of the linear actuator 11 and the compression cylinder 10 together.

[0048] Furthermore, the actuating assembly 9 comprises a dissipation chamber 20, which is in fluidic communication with the compression cylinder 10 and is designed to contain the compressed gas leaving the compression cylinder 10 so as to dissipate pressure waves generated by the intake and compression phases of the gas inside the compression cylinder 10.

[0049] In particular, the stationary portion 15 of the linear actuator 11 is arranged around the dissipation chamber 20. In more detail, the dissipation chamber 20 is arranged between the compression cylinder 10 and the support element 18.

[0050] The sliding assembly 12 comprises a connecting element 21 , which connects the compression piston 13 to the movable portion 16 of the linear actuator 11 ; and a dissipation chamber 22, which is in fluidic communication with the compression piston 13 and the compression cylinder 10, and is designed to contain the gas entering the compression cylinder 10 so as to dissipate pressure waves generated by the intake and compression phases of the gas inside the compression cylinder 10.

[0051] According to the present invention, the pumping unit 5 comprises a cooling circuit 23, which is formed inside the oscillating unit 3 and is designed to allow a cooling fluid to pass through the inside of the oscillating unit 3; and a reciprocating feed pump 24, which is arranged between the outer casing 2 and the oscillating unit 3 and is designed to damp the oscillations of the oscillating unit 3 with respect to the outer casing 2 and to feed the cooling fluid into the cooling circuit 23.

[0052] In particular, the cooling circuit 23 extends through the compression cylinder 10 and the linear actuator 11.

[0053] In the case described and illustrated here, the cooling circuit 23 comprises a plurality of channels formed inside the oscillating unit 3.

[0054] In particular, the cooling circuit 23 comprises a delivery channel 25, which is formed in the support element 18 and is in fluidic communication with the feed pump 24; a delivery channel 26, which is formed in the stationary portion 15 of the linear actuator 11 and is in fluidic communication with the delivery channel 25; a delivery channel 27, which is formed in the connecting frame 19 and is in fluidic communication with the delivery channel 26; an annular channel 28, which is formed in the compression cylinder 10 and is in fluidic communication with the delivery channel 27; a return channel 29, which is formed in the connecting frame 19 and is in fluidic communication with the annular channel 28; a return channel 30, which is formed in the stationary portion 15 of the linear actuator 11 and is in fluidic communication with the return channel 29; a return channel 31 , which is formed in the support element 18 and is in fluidic communication with the return channel 30.

[0055] The pumping unit 5 is immersed in the cooling liquid, which is contained inside the casing 2, in particular between the base support 35 and the support element 18, and is in fluidic communication with an inlet of the feed pump 24 and an outlet of the return channel 31.

[0056] In more detail, the delivery channel 26 and the return channel 30 are arranged inside the stationary portion 15 of the linear actuator 11 so that the passage of the cooling fluid through the delivery channel 26 and the return channel 30 cools the stationary portion 15.

[0057] In particular, the feed pump 24 extends along a respective longitudinal axis A2 substantially parallel to the central axis A1 of the compression cylinder 10. In practice, the feed pump 24 is coupled to the oscillating unit 3 and to the outer casing 2 in such a way that it is driven by the oscillations of the oscillating unit 3 with respect to the outer casing 2.

[0058] In more detail, the feed pump 24 is coupled to the oscillating unit 3 and to the outer casing 2 in parallel with the elastic assembly 4. In this way, the elastic elements 8 and the feed pump 24 form a spring-damper suspension system.

[0059] In the case described and illustrated here, which does not limit the present invention, the feed pump 24 is built into a respective elastic element 8. In practice, the feed pump 24 is arranged inside the helical spring of the respective elastic element 8.

[0060] It is understood that the feed pump 24 may adopt any other position in the space between the outer casing 2 and the oscillating unit 3, without having to be built into one of the elastic elements 8.

[0061] According to one embodiment, the pumping unit 5 comprises a plurality of feed pumps 24 arranged in parallel with one another between the outer casing 2 and the oscillating unit 3. In particular, the pumping unit 5 comprises one or more feed pumps 24 in parallel.

[0062] With reference to Figure 2, the feed pump 24 comprises a pumping cylinder 32, which extends along the longitudinal axis A2 and is integral with one of the oscillating unit 3 and the outer casing 2, and a pumping piston 33, which is arranged slidingly inside the pumping cylinder 32 integrally connected to the other of the oscillating unit 3 and the outer casing 2.

[0063] In the case described and illustrated here, the pumping piston 33 is integral with the external casing 2 and the pumping cylinder 32 is integral with the oscillating unit 3. In particular, the pumping cylinder 32 is fastened to the support element 18.

[0064] In practice, the pumping piston 33 is slidingly engaged in the pumping cylinder 32 in order to produce a reciprocating straight motion comprising an intake stroke, in which the cooling fluid is drawn into the pumping cylinder 32, and a delivery stroke, in which the pumping piston 33 forces the cooling fluid into the cooling circuit 23.

[0065] Furthermore, the feed pump 24 comprises a counter spring 34, which is arranged in the pumping cylinder 32 in order to exert a force countering the sliding of the pumping piston 33 inside the pumping cylinder 32, keeping the pumping piston 33 integral with the casing 2.

[0066] In use and with reference to Figure 1 , the actuation of the stationary portion 15 of the linear actuator 11 causes the movable portion 16 to slide in the sliding seat 17 along the central axis A1 . Since the movable portion 16 is integral with the connecting element 21 and the compression piston 13, the sliding of the movable portion 16 in the sliding seat 17 causes the compression piston 13 to slide inside the compression cylinder 10.

[0067] The elastic elements 14 generate a counter force between the connecting frame 19 and the connecting element 21 that causes the compression piston 13 to slide in a reciprocating manner inside the compression cylinder 10 so as to selectively draw and compress the gas inside the compression cylinder 10.

[0068] The electric current powering the linear actuator 11 , the friction caused by the sliding of the compression piston 13 inside the compression cylinder 10, and the compression of the gas in the compression cylinder 10 generate heat inside the actuating assembly 9.

[0069] The reciprocating sliding of the sliding assembly 12 with respect to the actuating assembly 9 along the central axis A1 causes the actuating assembly 9 to oscillate with respect to the outer casing 2. In other words, the distance between the outer casing 2 and the oscillating unit 3 measured along the central axis A1 varies intermittently.

[0070] The oscillations of the actuating assembly 9 with respect to the outer casing 2 determine the intake stroke and the delivery stroke of the pumping piston 33 inside the pumping cylinder 32. In this way, the feed pump 24 feeds the cooling fluid into the cooling circuit 23 in order to dissipate heat from the actuating assembly 9, while simultaneously damping the oscillations of the actuating assembly 9 with respect to the outer casing 2. It is understood that, according to additional embodiments that are not shown in the attached figures, the reciprocating machine 1 may take additional forms other than those shown in Figure 1 and may be used in a wide range of different applications. As an example, the reciprocating machine may be part of an internal combustion engine.

[0071] Finally, it is clear that the present invention comprises further variants of the described embodiments included in the scope of protection of the attached claims.

Claims

Claims1 . Pumping unit for feeding a cooling fluid into a reciprocating machine, which comprises an outer casing (2), an oscillating unit (3) arranged in the outer casing (2), and an elastic assembly (4), which elastically connects the oscillating unit (3) to the outer casing (2), the pumping unit (5) comprising:- a cooling circuit (23), which is formed inside the oscillating unit (3) and is designed to allow a cooling fluid to pass through the inside of the oscillating unit (3); and- at least one reciprocating feed pump (24), which is arranged between the outer casing (2) and the oscillating unit (3) and is designed to damp the oscillations of the oscillating unit (3) with respect to the outer casing (2) and to feed the cooling fluid into the cooling circuit (23).

2. Pumping unit according to Claim 1 , wherein the at least one feed pump (24) is coupled to the oscillating unit (3) and to the outer casing (2) in such a way that it is driven by the oscillations of the oscillating unit (3) with respect to the outer casing (2).

3. Pumping unit according to Claim 2, wherein the at least one feed pump (24) comprises a pumping cylinder (32), which is integral with one of the oscillating unit (3) and the outer casing (2), and a pumping piston (33), which is arranged slidingly inside the pumping cylinder (32) and is integrally connected to the other of the oscillating unit (3) and the outer casing (2).

4. Pumping unit according to any one of the preceding claims, wherein the at least one feed pump (24) is coupled to the oscillating unit (3) and to the outer casing (2) in parallel with the elastic assembly (4).

5. Pumping unit according to any one of the preceding claims, wherein the elastic assembly (4) comprises at least one first elastic element (8); the atleast one feed pump (24) being built into the at least one first elastic element (8).

6. Pumping unit according to any one of the preceding claims, and comprising a plurality of feed pumps (24) arranged in parallel with one another between the outer casing (2) and the oscillating unit (3); the pumping unit (5) preferably comprising two feed pumps (24) in parallel or four feed pumps (24) in parallel.

7. Reciprocating machine, preferably a piston machine, the reciprocating machine (1) comprising:- an outer casing (2);- an oscillating unit (3) arranged in the outer casing (2);- an elastic assembly (4), which elastically connects the oscillating unit (3) to the outer casing (2); and- a pumping unit (5) according to any one of the preceding claims.

8. Reciprocating machine according to Claim 7, wherein the oscillating unit (3) comprises:- an actuating assembly (9), which is connected to the outer casing (2) by the elastic assembly (4) and by the at least one feed pump (24), and comprises a compression cylinder (10) extending along a central axis (A1) and a linear actuator (11);- a sliding assembly (12), which comprises a compression piston (13) able to slide inside the compression cylinder (10); and- at least one second elastic element (14), which elastically connects the sliding assembly (12) to the actuating assembly (9); the linear actuator (11) being designed to slide the sliding assembly (12) in a reciprocating manner with respect to the actuating assembly (9) along the central axis (A1).

9. Reciprocating machine according to Claim 8, wherein the at least one feed pump (24) extends along a respective longitudinal axis (A2) substantially parallel to the central axis (A1) of the compression cylinder (10).

10. Reciprocating machine according to Claim 8 or 9, wherein the cooling circuit(23) extends through the compression cylinder (10) and the linear actuator (11).

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