Fluid machine

An object of the invention is to minimize energy loss to be generated at a driving shaft and a shaft seal device, when an electric rotating device is driven by an expansion-and-compressor device. According to a feature of the invention, a first driving shaft is rotationally supported by a housing and transmits a driving force from an engine to a second shaft of the expansion-and-compressor device, wherein a shaft seal device is provided on the first driving shaft for air-tightly sealing the inside of the housing from the outside of the housing. A power transmission control device (electromagnetic clutch or one way clutch) is operatively provided in a path between the first driving shaft and the second shaft, so that power transmission from the second shaft to the first driving shaft is cut off, to suppress any energy loss to be generated between the first driving shaft and the shaft seal device.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2003-171993 filed on Jun. 17, 2003, the disclosures of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a fluid machine having both a pumping and a motor functions, wherein the motor function is to convert an inside energy of working fluid to a rotational energy by expanding superheated gas in an isentropic manner, and the pumping function is to suck in and compress the working fluid.

BACKGROUND OF THE INVENTION

A fluid machine shown inFIG. 6is a fluid machine proposed by the inventors of the present invention in the course of developing the present invention. The fluid machine has a pumping mode for compressing and discharging working fluid, and a motor mode for converting fluid pressure to kinetic energy and thereby to output mechanical energy. The fluid machine operates in the following manner.

In this operational mode, a movable scroll102pof a pump-motor mechanism100pis rotated by applying a rotational force to a shaft109p, to thereby suck in and compress refrigerant.

More in detail, the shaft109pis rotated while an electromagnetic valve107pand an inlet port106pare closed. An expansion-and-compressor device, namely the fluid machine, sucks in the refrigerant from a low pressure port111p, compresses the same by working chambers103p, pumps out pressurized refrigerant through a pump-out port105pinto a high pressure chamber104pand discharges the pressurized refrigerant through a high pressure port110p, in the same manner to a well known scroll type compressor.

There are two ways for applying the rotational force to the shaft109a, according to one of which the expansion-and-compressor device is disconnected from an engine by cutting off power supply to an electromagnetic clutch300pand the rotational force is applied from an electric rotating machine200pto the shaft109a, and according to the other of which the expansion-and-compressor device is operatively connected to the engine and driven by the rotational force from the engine.

In this operational mode, the movable scroll102pis rotated by introducing superheated steam of the refrigerant into the high pressure chamber104pand expanding the superheated gas by the pump-motor mechanism100p, while the expansion-and-compressor device is disconnected from the engine by means of the electromagnetic clutch300p. The rotation of the movable scroll102pis transmitted to the shaft109pto obtain a mechanical output.

In the fluid machine explained above, it is necessary to air-tightly seal a gap between the shaft109aand a housing230pof the fluid machine, for example by a shaft seal device333such as a lip seal, because the shaft109aextends from the outside into the inside of the housing230p.

Since the air-tightness at the gap between the shaft109aand the housing230pis obtained by the shaft seal device333, in which the shaft seal device333is pressed against an outer peripheral surface of the shaft109aat a certain contact pressure, an energy loss will be generated due to friction resistance at the shaft seal device333when the shaft109ais rotated.

Accordingly, an efficiency of energy collection will be decreased in the above described fluid machine, because the energy to be collected is decreased in the motor mode operation.

The maximum energy to be collected in the motor mode operation is smaller in comparison with collected heat quantity, as seen from p-h diagram shown inFIG. 7. Accordingly, the energy loss at the shaft seal device333for the energy collection occupies a relatively large portion of the maximum energy to be collected.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention, in view of the above mentioned problems, to provide a fluid machine which can operate with less energy loss.

According to a feature of the present invention, a fluid machine has an expansion-and-compressor device which selectively operates as an expansion device for collecting waste heat energy from an internal combustion engine and for converting the collected heat energy into mechanical rotational force, or as a compressor for compressing refrigerant for an air-conditioner. The fluid machine further has an electric rotating device disposed in a housing for the expansion-and-compressor device and operatively connected thereto, so that the electric rotating device is operated as an electric motor for generating a rotational force to drive the expansion-and-compressor device when the electric power is supplied thereto, or the electric rotating device is operated as an electric power generator for generating electric power when it is driven by the expansion-and-compressor device. A first driving shaft is rotationally supported by the housing and operatively connected to an outside driving source (an engine), and a second shaft is operatively connected to the expansion-and-compressor device, so that the driving force is transmitted from the engine to the expansion-and-compressor device, wherein a shaft seal device is provided on the first driving shaft for air-tightly sealing the inside of the housing from the outside of the housing. A power transmission control device (electromagnetic clutch or one way clutch) is operatively provided in a path between the first driving shaft and the second shaft, so that power transmission from the second shaft to the first driving shaft is cut off.

According to this feature of the invention, the first driving shaft will not be rotated when the electric rotating device is driven by the rotational force from the expansion-and-compressor device so that any energy loss to be generated between the first driving shaft and the shaft seal device can be suppressed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A first embodiment of the present invention will now be explained with reference toFIGS. 1 through 3. A fluid machine of the present invention is used to, for example, a motor vehicle, which is equipped with an air-conditioning system and a waste heat utilizing system. The waste heat utilizing system is composed of a Rankine cycle, which collects waste heat from an internal combustion engine for generating a running power for the motor vehicle. In addition, in the fluid machine of the present invention, the heat generated by the fluid machine is utilized for performing an air-conditioning operation for the motor vehicle.

InFIG. 1, a reference numeral10designates a fluid machine comprising an expansion-and-compressor device, so that the fluid machine operates as a compressor for compressing a gas-phase refrigerant (this is referred to as a pump mode operation) and also as a power generator for generating a mechanical driving force by converting fluid pressure of superheated steam into kinetic-energy (this is referred to as a motor mode operation). A reference numeral11designates a heat radiating device connected to an outlet side of the fluid machine10for cooling down the refrigerant gas by heat radiation (The heat radiating device11will be also referred to as a condenser).

A reference numeral12designates a receiver for dividing the refrigerant from the condenser11into a gas-phase refrigerant and a liquid-phase refrigerant. A reference numeral13is an expansion valve of a temperature-dependent type for expanding and decreasing the pressure of the liquid-phase refrigerant from the receiver12, more particularly for decreasing the pressure of the refrigerant in an isenthalpic manner and controlling an opening degree of a passage for the refrigerant so that the degree of superheat of the refrigerant to be sucked into the fluid machine10will be maintained at a predetermined value when the fluid machine10is operating in the pump mode operation.

A reference numeral14designates a heat absorbing device (also referred to as an evaporator) for evaporating the refrigerant from the expansion valve13and thereby absorbing heat. The above fluid machine10, the condenser11, the receiver12, the expansion valve13and the evaporator14constitute a refrigerating cycle.

A heating device30is disposed in a refrigerant passage connected between the fluid machine10and the condenser11and heats the refrigerant flowing through the refrigerant passage by heat-exchanging the refrigerant with engine cooling water flowing through the heating device30. A switching valve21of a three-way valve is provided in a circuit (Hot water circuit) for the engine cooling water, so that the flow of the cooling water through the heating device30is switched on and off.

A first by-pass passage31is connected between the receiver12and the heating device30so that the liquid-phase refrigerant will flow from the receiver12to an inlet side of the heating device30when a liquid pump32is operated. A check valve31ais provided in this first by-pass passage so that only the flow of the refrigerant from the receiver12to the heating device30is allowed. The liquid pump32in this embodiment is an electrically driven pump.

A second by-pass passage34is connected between the outlet side of the fluid machine10and the inlet side of the condenser11and a check valve34ais disposed in this passage, so that the refrigerant is allowed to flow from the fluid machine10to the condenser11, only when the fluid machine10is operated in the motor mode operation.

A check valve14ais provided in the refrigerating cycle so that the refrigerant is allowed to flow from the outlet side of the evaporator14to the inlet side of the fluid machine10when the fluid machine10is operated in the pump mode operation. An ON-OFF valve35is an electromagnetic type for opening and closing the passage for the refrigerant passage, wherein the valve35and the switching valve21are controlled by an electronic control unit (not shown).

A water pump22circulates the engine cooling water, and a radiator23is a heat exchanger for heat-exchanging the heat of the engine cooling water with the ambient air to cool down the engine cooling water. A by-pass passage for by-passing the radiator23and a valve for controlling an amount of the engine cooling water flowing through the radiator23are omitted inFIG. 1.

The water pump22is a mechanical type pump driven by the engine20in this embodiment. It is, however, possible to replace it with an electric type pump operated with an electric motor.

Now, the fluid machine10will be explained with reference toFIG. 2. The fluid machine10according to the embodiment comprises the expansion-and-compressor device100for selectively expanding or compressing the refrigerant (the gas-phase refrigerant in this embodiment), an electric rotating device200for generating an electric power when a rotational force is applied thereto and for generating a rotational force when the electric power is applied thereto, an electromagnetic clutch300for controlling (switching on and off) a power transmission of a rotational force from the engine20to the expansion-and-compressor device100, and a transmission device400comprising a planetary gear drive for changing a path for the power transmission among the expansion-and-compressor device100, the electric rotating device200and the electromagnetic clutch300and for increasing and decreasing the rotational speed to be transmitted.

The electric rotating device200comprises a stator210and a rotor220rotating within a space of the stator210, wherein a winding is wound on the stator210and a permanent magnet is fixed to the rotor220.

When the electric power is supplied to the stator210, the rotor220will be rotated to operate as an electric motor so that it drives the expansion-and-compressor device100, whereas it will operate as an electric power generator when a rotational force is applied to the rotor220.

The electromagnetic clutch300comprises a pulley310to be connected to the engine20via a V-belt, an electromagnetic coil320and a friction plate330which will be displaced by an electromagnetic force generated at the electromagnetic coil320when it is energized. The coil320will be energized when the rotational force from the engine20will be transmitted to the fluid machine10, and the supply of the electric power to the coil320will be cut off when the power transmission of the rotational force to the engine shall be cut off.

The expansion-and-compressor device100has the same construction to a well known scroll type compressor, and comprises a middle housing101fixed to a stator housing230of the electric rotating device200, a fixed scroll102connected to the middle housing101, and a movable scroll103disposed in a space defined by the middle housing101and the fixed housing102. The movable scroll103is rotated in the space with an orbit motion to form multiple working chambers V. The device100further comprises a high pressure chamber104, passages105and106operatively communicating the working chamber V with the high pressure chamber104, and a valve mechanism107for controlling an opening and closing of the passage106.

The fixed scroll102comprises a base plate102aand a spiral scroll wrap102bprotruding from the base plate102atowards the middle housing101, whereas the movable scroll likewise has a base plate103aand a spiral scroll wrap103bprotruding from the base plate103atowards the fixed scroll, wherein wall portions of the spiral scroll wraps102band103bare contacted with each other to form the working chambers V. When the movable scroll103is rotated, the space of the working chamber V will be expanded or decreased.

A shaft108(a second shaft) is rotationally supported by the middle housing101and provided with an internal gear401, which is a part of the transmission device400. The shaft108is further provided with an eccentric shaft108awhich is eccentric from a rotational axis of the shaft108to operate as a crank arm and operatively connected to the movable scroll103over a bush103dand a bearing103c.

The bush103dis connected to the eccentric shaft108ain such a way that the bush103dcan be displaced by a certain small distance in a plain perpendicular to the axis of the eccentric shaft108a, so that the movable scroll103will be displaced in a direction that contact pressure between the scroll wraps102band103bwill be increased by means of a reaction force for compression.

A reference numeral109designates an auto rotation preventing mechanism for preventing the autorotation of the movable scroll103and allowing the orbital motion thereof. When the shaft108is rotated by one revolution, the movable scroll103is moved around the shaft108with the orbital motion, and the volume of the working chamber V will be decreased as the working chamber is moved from the outer position to the inner position. The mechanism109here comprises a ring and a pair of pins.

The passage105operates as an outlet port for pumping out the pressurized refrigerant by communicating the working chamber V, which will reach its minimum volume during the pump mode operation, with the high pressure chamber104, whereas the passage106operates an inlet port for introducing high-temperature and high-pressure refrigerant, namely superheated steam of the refrigerant, from the high pressure chamber104into the working chamber V, the volume of which becomes at its minimum value during the motor mode operation.

The high pressure chamber104has a function of equalizing the pressure of the refrigerant by smoothing pulsation of the pumped out refrigerant. A high pressure port110is formed in a housing forming the high pressure chamber104and the port110is connected to the heating device30and the heat radiating device11.

A low pressure port111is formed in the stator housing230for communicating a space defined by the stator housing230and the fixed scroll102with the evaporator14and the second by-pass passage34.

A discharge valve107aand a valve stopper107bare fixed to the base plate102aof the fixed scroll102by a bolt107c, wherein the valve107ais a check valve of a reed valve type for preventing the pumped out refrigerant from flowing back to the working chamber V from the high pressure chamber104, and the stopper107bis a plate for limiting the movement of the reed valve107a.

A spool107dis a valve for opening and closing the inlet port106, an electromagnetic valve107eis a control valve for controlling pressure in a back pressure chamber107fby opening and closing a passage between back pressure chamber107fand the high pressure chamber104or the space communicated with the low pressure port111. A spring107gis disposed in the back pressure chamber107fto urge the spool107din a direction to close the inlet port106, and an orifice107hhaving a certain flow resistance is formed in the passage connecting the high pressure chamber104with the back pressure chamber107f.

When the electromagnetic valve107eis opened, the back pressure chamber107fis communicated to the space defined by the stator housing230(the lower pressure side), then the pressure in the back pressure chamber107fwill be decreased lower than that in the high pressure chamber104and finally the spool107dwill be moved against the spring force of the spring107gin a direction to open the inlet port106. Since the pressure drop at the orifice107his so high that an amount of the refrigerant flowing from the high pressure chamber104into the back pressure chamber107fis negligible small.

On the other hand, when the electromagnetic valve107eis closed, the pressure in the back pressure chamber107fbecomes equal to that in the high pressure chamber104and then the spool107dwill be moved in the direction to close the inlet port106. As above, the spool107d, the electromagnetic valve107e, the back pressure chamber107fand the orifice107hconstitute a pilot-type electric valve for opening and closing the inlet port106.

The transmission device400is composed of a planetary gear mechanism having a ring shape internal gear401(ring gear) integrally formed with and rotated with the shaft108, multiple (e.g. three) planetary gears402supported by a planetary carrier402aand being engaged with the ring gear401, and a sun gear403being engaged with the planetary gears402.

The sun gear403is integrally formed with the rotor220of the electric rotating device200and the planetary gears402are integrally fixed to a shaft331to which a friction plate330is connected.

A one-way clutch500allows a rotation of the shaft331only in one rotational direction, a bearing332rotationally supports the shaft331, a bearing404rotationally supports the sun gear403, namely the rotor220with respect to the shaft331, a bearing405rotationally supports the internal gear401with respect to the shaft108, and a bearing108crotationally supports the shaft108with respect to the middle housing101.

A lip seal333is a seal for preventing the refrigerant from flowing out through a gap between the shaft331and the stator housing,230, in which the lip seal is contacted with (pressed against) the outer peripheral surface of the shaft331.

Now, an operation of the fluid machine as described above will be explained.

The pump mode operation is the operation in which a rotational force is applied to the shaft108and the expansion-and-compressor device100is thereby operated to compress the refrigerant by rotating the movable scroll103with the orbit motion. In this operation, the expansion-and-compressor device100is also referred to as the compressor device100.

In this pump mode operation, the electromagnetic valve107eis closed and thereby the inlet port106is closed. When the shaft108and the movable scroll103are rotated, the compressor device100sucks the refrigerant from the low pressure port111, compresses the refrigerant by the working chamber V, pumps out the pressurized refrigerant to the high pressure chamber104through the outlet port105, and finally discharges the high pressure refrigerant to the heat radiating device (condenser)11through the high pressure port110. The refrigerant from the low pressure port111flows through the inside of the stator housing230and flows into the compressor device100.

In this operation, there are two methods for applying the rotational force to the shaft108, namely one of them is a method in which the supply of the electric power to the electromagnetic clutch300is cut off and thereby the compressor device100is mechanically disconnected from the pulley310and then the electric rotating device200is operated as the electric motor by supplying the electric power thereto so that the rotational force of the device200will be applied to the compressor device100. In the other method, the compressor device100is mechanically connected to the engine20over the electromagnetic clutch300, and the driving force from the engine20is applied to the compressor device100.

In this operation, since the planetary carrier402ais not rotated because of the one-way clutch500, the rotational force of the electric rotating device200will be transmitted to the compressor device100through the transmission device400with the rotational speed being reduced thereby.

In the case that the electromagnetic clutch300is supplied with the electric power to mechanically connect the compressor device100with the engine20to transmit the rotational force from the engine20to the compressor device100, the electric power is also supplied to the electric rotating device200to generate electromagnetic force at the stator and thereby to apply a torque to the rotor220so that the sun gear403and the rotor220may not be rotated.

As a result, the rotational force transmitted from the engine20to the electromagnetic clutch300(the pulley310) will be further transmitted to the compressor device100through the transmission device400with the rotational speed being increased thereby.

The motor mode operation is the operation in which high pressure and superheated steam of the refrigerant, which is superheated by the heating device30, is introduced into the expansion-and-compressor device100and the refrigerant is expanded in the working chamber V, so that a rotational force is generated by rotating the movable scroll103with the orbit motion in the different rotational direction to that for the pump mode operation. In this operation, the expansion-and-compressor device100is also referred to as the expansion device100.

The rotational force generated at the expansion device100is-used for rotating the rotor220to generate the electric power at the electric rotating device200, and the electric power will be charged into a battery.

More in detail, the supply of the electric power to the electromagnetic clutch300is cut off and the electromagnetic valve107eis opened so that the inlet port106is also opened. Then the high pressure and superheated refrigerant heated by the heating device30will be introduced into the working chamber V through the inlet port106and the superheated refrigerant will be expanded in the working chamber V.

As a result, the movable scroll103will be rotated by the expansion of the superheated refrigerant, and the refrigerant which has been expanded and the pressure of which has been decreased will be discharged to the condenser11through the low pressure port111.

In this operation, when the movable scroll103is rotated in the reversed direction to that of the pump mode operation, the planetary gears402(namely, the planetary carrier402a) are urged to rotate likewise in the reversed direction around the shaft331. However, since the rotation of the shaft331(the first shaft) in the reversed direction is restricted by the one way clutch500, the planetary gears402and the planetary carrier402acan not be rotated in the reversed direction around the shaft331, while the planetary gears402will be rotated on their own axis.

Accordingly, the rotational energy given to the movable scroll103is transmitted to the rotor220of the electric rotating device200through the transmission device400with the rotational speed being increased.FIG. 3shows a diagram explaining the above mentioned operation.

In this embodiment, the transmission device400and the one way clutch500constitute a power transmission control device.

As understood from the above operation, the electric rotating device200is arranged in a path of transmitting the driving force at such a point closer to the expansion-and-compressor device100than the power transmission control device (the transmission device400and the one way clutch500).

An operation of the refrigerating cycle and the waste heat collecting cycle of the above mentioned embodiment will be explained.

The air-conditioning operational mode is an operational mode in which air is cooled down at the evaporator14and the heat of the refrigerant is radiated at the condenser11.

In this operational mode, the operation of the liquid pump32is stopped, the ON-OFF valve35is opened and the device100is operated as the compressor device (pump mode operation). And the engine cooling water is circulated by by-passing the heating device30by means of the switching valve21.

The refrigerant flows in this operational mode from and back to the compressor device100through the heating device30, heat radiating device11(condenser), the receiver12, the expansion valve13, and the evaporator14. In this flow of the refrigerant, the refrigerant will not be heated by the heating device30since the engine cooling water is flowing by by-passing it.

The low pressure refrigerant, which is decompressed at the expansion valve13, will be evaporated at the evaporator14by absorbing the heat from the air flowing through the evaporator14and the cooled down air will be blown out into a passenger room of the motor vehicle. The evaporated gas-phase refrigerant will be again compressed by the compressor device100and the high temperature compressed refrigerant is then cooled down and condensed at the condenser11.

Although Freon (HFC134a) is used as the refrigerant (working fluid) in this embodiment, any other refrigerant which will be liquidized at a higher pressure side can be used (not limited to HFC134a).

This is an operational mode in which the operation of the air-conditioning is stopped, namely the operation of the compressor device100is stopped, and instead the waste heat from the engine20is collected and converted to mechanical energy.

In this operational mode, the liquid pump32is operated, the ON-OFF valve35is closed and the device100is operated as the expansion device (motor mode operation). And the engine cooling water is circulated through the heating device30by means of the switching valve21.

The refrigerant flows in this operational mode from and back to the expansion device100through the second by-pass passage34, heat radiating device11, the receiver12, the first by-pass passage31, the pump32and the heating device30. The flow of the refrigerant in the heat radiating device11is different from that for the pump mode operation.

As above, the superheated steam heated by the heating device30flows into the expansion device100and expanded therein so that the enthalpy of the refrigerant will be decreased in an isentropic manner. Accordingly, the electric power corresponding to an amount of decrease of the enthalpy will be charged into the battery.

The refrigerant from the expansion device100will be cooled down and condensed at the heat radiating device11and charged in the receiver12. Then the liquid-phase refrigerant will be sucked from the receiver12by the liquid pump32and pumped out to the heating device30. The liquid pump32pumps out the liquid-phase refrigerant at such a pressure that superheated steam at the heating device30may not flow in a backward direction.

As explained above, the shaft331, with which the lip seal333is contacted, is not rotated in the motor mode operation because of the transmission device400and the one way clutch500, so that energy collected by the expansion-and-compressor device100will not be lost by the lip seal333.

In the first embodiment, the power transmission control device is constituted by the transmission device400and the one way clutch500. However, in the second embodiment, as shown inFIG. 4, an electromagnetic clutch600is arranged within the housing (for example, the stator housing230) of the expansion-and-compressor device100and between the first and second shafts331and108, and the supply of electric power to the electromagnetic clutch600is controlled by an electronic control unit601.

In the motor mode operation and the pump mode operation in which the compressor device100is driven by the electric rotating device200, the electric power to the electromagnetic clutch600is cut off to disconnect the second shaft108from the first shaft331. In the pump mode operation in which the compressor device100is driven by the engine20, the electric power is supplied to the electromagnetic clutch600to connect the shafts108and331with each other to transmit the driving force from the engine20to the compressor device100.

In this embodiment, the electromagnetic clutch600and the control unit601constitute the power transmission control device.

The third embodiment shown inFIG. 5is a modification of the above explained second embodiment, in which a one way clutch700is arranged between the first and second shafts331and108, instead of the electromagnetic clutch600.

According to this embodiment, the transmission of the driving force is likewise allowed from the shaft331to the shaft108and the transmission of the rotational force in the reversed direction (from the shaft108to the shaft331) is cut off by the one way clutch700.

The expansion-and-compressor device100of the scroll type can be also replaced by any other type of expansion and compressor devices, such as a rotary type, a piston type, a vane type and so on.

Although the collected waste heat energy from the engine is converted into the electric power by the expansion-and-compressor device100and charged in the battery in the above embodiment, the collected energy can be converted into mechanical energy, for example, into kinetic energy by a flywheel, or into elastic potential energy by springs.

The fluid machine should not be limited to the use for the automobile compressor device having Rankine cycle.

In the above embodiments, the single device is used for performing two functions, one of which is to convert the internal energy of the working fluid into the rotational energy by expanding the superheated steam in the isentropic manner and the other of which is to compress the working fluid. The present invention, however, shall not be limited to the single device. For example, the fluid machine may be provided with two independent devices, one of which is a device for converting the internal energy of the working fluid into the rotational energy by expanding the superheated steam in the isentropic manner and the other of which is another device for compressing the working fluid.