Patent Application
20150023824
The present invention relates to a scroll-type expander and a fluid machine having the scroll-type expander.
Patent Document 1 describes a scroll-type expander configured to introduce a high-temperature and high-pressure gas-phase working medium (refrigerant), which has evaporated by an evaporator, into an expansion chamber via a through hole formed at the center of a base plate (base) of a fixed scroll. In such a scroll-type expander, since a working fluid supplied from the outside is directly guided into the expansion chamber, heat loss, pressure loss, or the like of the working fluid in the scroll-type expander is reduced.
Patent Document 1: Japanese Patent No. 4537948
However, in the scroll-type expander described in Patent Document 1, a case in which the working fluid that is not sufficiently vaporized by the evaporator is supplied, that is, a case in which a liquid-phase working fluid is introduced into the expansion chamber, is not taken into account. When a liquid-phase working fluid is introduced into the expansion chamber, the liquid-phase working fluid also enters into sliding portions or rotating portions inside the expansion chamber to cause a lubricant to flow away and thus seizure or the like may occur in a thrust bearing portion. Accordingly, the scroll-type expander described in Patent Document 1 may have problems in terms of durability and reliability.
Here, in order to prevent introduction of a liquid-phase working fluid into the expansion chamber, the scroll-type expander would be configured to introduce a working fluid, which is supplied from the outside, into the expansion chamber via a suction chamber or the like that can reserve a liquid-phase working fluid.
However, in this case, additional components (such as a casing) for forming the suction chamber or the like are required, which complicates the structure, thereby causing an increase in cost or an increase in size of the apparatus. Since the suction chamber or the like has a volume of a certain magnitude, pressure loss or heat loss of the working fluid may occur in the suction chamber or the like, and energy loss may be increased.
The present invention is made in consideration of the above-mentioned circumstances and an object thereof is to provide a scroll-type expander having a relatively simple structure, small energy loss, and high durability and reliability, and to provide a fluid machine having the scroll-type expander.
Accordingly, according to an aspect of the present invention, there is provided a scroll-type expander that has a fixed scroll and an orbiting scroll, each of which has a scroll portion rising upright on a base thereof, the scroll-type expander generating a drive force by causing a working fluid to expand in an expansion chamber formed between the scroll portion of the fixed scroll and the scroll portion of the orbiting scroll, the scroll-type expander including: a working fluid passage that is formed in the base of the fixed scroll and that extends from a suction port open to the outside to an inlet open to the inside of the expansion chamber so as to guide the working fluid, which has flowed into the suction port, to the expansion chamber; and an anti-rotation mechanism that is disposed between a fixed portion of the scroll-type expander and the base of the orbiting scroll, that receives a thrust force acting on the orbiting scroll, and that prevents a rotation of the orbiting scroll, in which the anti-rotation mechanism is a ball-coupling anti-rotation mechanism using balls as rolling members.
Here, the scroll-type expander may be used alone, or alternatively, the scroll-type expander and a pump unit driven with a drive force generated from the scroll-type expander so as to draw in and discharge the working fluid may be integrated as a unified body, to constitute a fluid machine, or alternatively, the scroll-type expander and a power generation unit driven with a drive force generated from the scroll-type expander so as to generate electric power may be integrated as a unified body to constitute a fluid machine.
It has been confirmed by experiments that the ball-coupling anti-rotation mechanism using balls as rolling members has high durability even in an insufficient lubrication state.
The scroll-type expander is configured to receive a thrust force acting on the orbiting scroll and to prevent the rotation of the orbiting scroll through the use of the anti-rotation mechanism. Accordingly, even when a liquid-phase working fluid is supplied from the outside and lubrication becomes insufficient, it is possible to guarantee high durability and reliability without causing any problem. Since the working fluid passage is formed in the base of the fixed scroll and the working fluid supplied from the outside is directly guided to the expansion chamber, it is possible to relatively simplify the structure and to reduce pressure loss or heat loss of the working fluid.
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
The engine 10 is a water-cooled internal combustion engine and is cooled with a coolant flowing in a coolant circulation passage 11. In the coolant circulation passage 11, an evaporator 22 of the Rankine cycle device 2 is disposed.
The Rankine cycle device 2 recovers waste heat of the engine 10 from the coolant of the engine 10, converts the recovered waste heat into a drive force, and outputs the drive force. The Rankine cycle device 2 includes a circulation passage 21 of a working fluid (refrigerant) and an evaporator 22, an expander 23, a condenser 24, and a pump 25 are arranged in this order in the circulation passage 21.
The evaporator 22 is a heat exchanger that heats and evaporates (vaporize) the working fluid by causing the coolant having absorbed heat from the engine 10 to exchange heat with the working fluid.
The expander 23 is a scroll-type expander that generates a drive force by causing the working fluid as superheated vapor heated by the evaporator 22 to expand and converting the heat into rotational energy.
The condenser 24 is a heat exchanger that cools and condenses (liquefies) the working fluid by causing the working fluid having passed through the expander 23 to exchange heat with external air.
The pump 25 is a mechanical pump that sends out the working fluid liquefied by the condenser 24 to the evaporator 22. The pump 25 is driven to draw in and discharge the working fluid, whereby the working fluid circulates in the circulation passage 21.
In this embodiment, a “pump-integrated expander 27” is constituted in which the expander 23 and the pump 25 are connected to each other via a rotating shaft 26. That is, the rotating shaft 26 of the pump-integrated expander 27 has a function of an output shaft of the expander 23 and a function of a drive shaft of the pump 25.
The Rankine cycle device 2 is first started by causing the engine 10 to drive the pump 25 (the pump unit in the pump-integrated expander 27), and then when the expander 23 (the expansion unit in the pump-integrated expander 27) generates sufficient drive force, the pump 25 is driven with the drive force generated from the expander 23.
A transmission mechanism 3 includes a pulley 31 attached to the rotating shaft 26 of the pump-integrated expander 27, a crank pulley 32 attached to a crank shaft 10a of the engine 10, a belt 33 wound on the pulley 31 and the crank pulley 32, and an electromagnetic clutch 34 disposed between the rotating shaft 26 of the pump-integrated expander 27 and the pulley 31.
By turning on (engaging) or off (disengaging) the electromagnetic clutch 34, the drive force can be transmitted or cut off between the engine 10 and the Rankine cycle device 2 (specifically, the pump-integrated expander 27).
A control unit 4 has a function of controlling the operation of the electromagnetic clutch 34 and controls activation and deactivation of the Rankine cycle device 2 by the on and off control of the electromagnetic clutch 34.
That is, the control unit 4 starts the Rankine cycle device 2 by turning on (engaging) the electromagnetic clutch 34 to activate the pump 25 (the pump unit in the pump-integrated expander 27) by the use of the engine 10. Thereafter, when the expander 23 (the expansion unit in the pump-integrated expander 27) is activated and starts to generate a drive force, a part of the drive force generated from the expander 23 is used to drive the pump 25 and the other drive force is transmitted to the engine 10 via the transmission mechanism 3 to assist the output (driving force) of the engine 10.
Although not illustrated in the drawings, the working fluid may be circulated to bypass the expander 23 by providing an expander bypass passage and a bypass valve opening and closing the expander bypass passage and by opening the bypass valve if necessary (for example, when superheating of the working fluid in the evaporator 22 is insufficient). The evaporator 22 may be configured to exchange heat between the working fluid of the Rankine cycle device 2 and the exhaust air of the engine 10.
The pump-integrated expander 27 is a fluid machine in which the pump 25 circulating the working fluid of the Rankine cycle device 2 and the expander 23 generating a drive force by causing the working fluid heated and vaporized by the evaporator 22 to expand are integrated as a unified body using the rotating shaft 26.
The pump-integrated expander 27 includes an expansion unit 50 constituting the expander 23 and a pump unit 60 constituting the pump 25.
The expansion unit 50 (scroll-type expander) includes a fixed scroll 51, an expander housing 52, and an orbiting scroll 53.
The fixed scroll 51 has a disc-like base 51a and a spiral scroll portion 51b rising upright on one surface (the left surface in the drawing) of the base 51a.
The expander housing 52 is formed in a tubular shape having a large-inner-diameter portion 52a and a small-inner-diameter portion 52b and a part of the inner circumferential surface of the large-inner-diameter portion 52a is fitted to a part of the outer circumferential surface of the base 51a of the fixed scroll 51.
The orbiting scroll 53 is received in the large-inner-diameter portion 52a of the expander housing 52. Similarly to the fixed scroll 51, the orbiting scroll 53 has a disc-like base 53a and a spiral scroll portion 53b rising upright on one surface (the right surface in the drawing) of the base 53a. A tubular portion 53c protruding toward the pump unit 60 is formed on the other surface (the left surface in the drawing) of the base 53a.
The fixed scroll 51 and the orbiting scroll 53 are arranged so that the scroll portions 51b and 53b thereof engage with each other, and an expansion chamber 54 for causing the working fluid to expand is formed between the scroll portion 51b of the fixed scroll 51 and the scroll portion 53b of the orbiting scroll 53.
Substantially at the center of the base 51a of the fixed scroll 51, a working fluid passage 51e extending from a suction port 51c open to the outside to an inlet 51d open to the expansion chamber 54 is provided. The cross-sectional area of the working fluid passage 51e is less than or equal to the opening area of the suction port 51c. The working fluid sent to the expander 23 (the expansion unit 50) via the evaporator 22 flows from the suction port 51c and is guided to the expansion chamber 54 via the working fluid passage 51e and the inlet 51d.
An eccentric bush 83 is disposed inside the tubular portion 53c formed in the base 53a of the orbiting scroll 53 with a needle bearing 55 interposed therebetween. The eccentric bush 83 constitutes a driven crank mechanism 80.
The working fluid guided to the expansion chamber 54 expands in the expansion chamber 54, and the orbiting scroll 53 makes orbiting motion relative to the fixed scroll 51 with the expansion of the working fluid in the expansion chamber 54. The orbiting motion of the orbiting scroll 53 is converted into rotational motion of the rotating shaft 26 by the driven crank mechanism 80.
Here, in order to prevent the rotation of the orbiting scroll 53 during the orbiting motion and to receive a thrust force acting on the orbiting scroll 53, an anti-rotation mechanism 56 is disposed between the base 53a of the orbiting scroll 53 and an end face (fixed portion) of the expander housing 52 opposed thereto.
The anti-rotation mechanism 56 is a ball-coupling anti-rotation mechanism using balls as rolling members and includes a ring-like fixed-side plate 561 attached to a stepped face 52c connecting the large-inner-diameter portion 52a and the small-inner-diameter portion 52b of the expander housing 52, a ring-like orbiting-side plate 562 attached to a face of the base 53a of the orbiting scroll 53 opposite to the scroll portion 53b, and multiple balls 563 rollably supported between the fixed-side plate 561 and the orbiting-side plate 562.
In the fixed-side plate 561, annular race grooves 564 of which the groove cross-section has an arc-like shape are formed at equal intervals in the circumferential direction. The annular race grooves 564 are formed to correspond to the orbiting motion of the orbiting scroll 53.
In the orbiting-side plate 562, semi-spherical or bowl-like concave portions 565 for receiving the balls 563 in a rollable manner are formed at equal intervals in the circumferential direction. The number of concave portions 565 is equal to the number of annular race grooves 564 of the fixed-side plate 561. In the orbiting-side plate 562, the inner edge portion thereof is fixed to the base 53a of the orbiting scroll 53 by a pin 566, and a predetermined gap C is formed between the outer edge portion including an area having the concave portions 565 formed therein and the base 53a of the orbiting scroll 53. The gap C allows the elastic deformation of the outer edge portion of the orbiting-side plate 562 toward the orbiting scroll 53.
The balls 563 are rollably arranged between the annular race grooves 564 of the fixed-side plate 561 and the concave portions 565 of the orbiting-side plate 562.
When the orbiting scroll 53 moves around, the balls 563 roll along the corresponding annular race grooves 564 of the fixed-side plate 561 and thus the rotation of the orbiting scroll 53 is prevented.
Referring to
The pump housing 65 includes a first housing 66 having a recessed portion, in which the driving gear 61 and the driven gear 63 are disposed, on a face thereof on the expansion unit 50 side, and a second housing 67 that is disposed on the expansion unit 50 side of the first housing 66 so as to close the recessed portion. The recessed portion of the first housing 66 closed by the second housing 67 serves as a pump chamber 64.
In the second housing 67, a tubular portion 67a protruding to the expansion unit 50 is formed, and the outer circumferential surface of the tubular portion 67a is fitted to the inner circumferential surface of the small-inner-diameter portion 52b of the expander housing 52.
The rotating shaft 26 extends to pass through the pump housing 65 (the first housing 66 and the second housing 67) and has a large-diameter portion 26a at an end on the expansion unit 50 side. The rotating shaft 26 is rotatably supported by a ball bearing 68 disposed on the first housing 66 side and a ball bearing 69 disposed on the inner side of the tubular portion 67a of the second housing 67. The driven gear shaft 62 is rotatably supported by bearings 70 and 71 disposed in the first housing 66 and the second housing 67, respectively.
The pulley 31 and the electromagnetic clutch 34 constituting the transmission mechanism 3 are arranged on one end (the left side in the drawing) of the rotating shaft 26. The other end (the right side in the drawing) of the rotating shaft 26 is connected to the orbiting scroll 53 via the driven crank mechanism 80.
The driven crank mechanism 80 includes a flange portion 81 fixed to an end face of the large-diameter portion 26a of the rotating shaft 26, a crank pin 82 disposed on an end face of the flange portion 81 in a manner such that the crank pin 82 is off-centered with respect to the center of the rotating shaft 26, and an eccentric bush 83 disposed inside the tubular portion 53c of the orbiting scroll 53 with the needle bearing 55 interposed therebetween. The crank pin 82 is inserted into an insertion hole formed at a position eccentric from the bush center of the eccentric bush 83 and the eccentric bush 83 is configured to oscillate with respect to the crank pin 82. Accordingly, the crank pin 82 also makes orbiting motion with the orbiting motion of the eccentric bush 83.
The orbiting motion of the orbiting scroll 53 is converted into rotational motion of the rotating shaft 26 by the driven crank mechanism 80, and the pump unit 60 is driven by the rotation of the rotating shaft 26.
In order to balance the eccentric bush 83 and the orbiting scroll 53 and to suppress generation of vibrations in the expansion unit 50, a counterweight (balance weight) 84 is fixed to the eccentric bush 83. The oscillating range of the eccentric bush 83 with respect to the crank pin 82 is regulated by engagement of a restriction hole 81 a formed in the flange portion 81 and a restriction protrusion 83b formed in the eccentric bush 83.
In the above-mentioned pump-integrated expander 27, the expansion unit 50 constituted as a scroll-type expander generates a drive force by causing the working fluid to expand in the expansion chamber 54. More specifically, the orbiting scroll 53 moves around with the expansion of the working fluid in the expansion chamber 54, the orbiting motion of the orbiting scroll 53 is converted into rotational motion (driving force) of the rotating shaft 26 by the driven crank mechanism 80, and the pump unit 60 is driven with the rotational motion (driving force).
Here, the working fluid supplied from the outside to the expansion unit 50 is introduced into the expansion chamber 54 via only the working fluid passage 51e formed in the base 51a of the fixed scroll 51, and a space (buffer space) such as a suction chamber having a cross-sectional area greater than that of the working fluid passage 51e is not present on the way. Accordingly, components for forming the space (buffer space) such as the suction chamber are not required and thus an increase in number of components can be reduced, thereby realizing a simple structure. Since the working fluid is introduced into the expansion chamber 54 via only the working fluid passage 51e, it is possible to reduce pressure loss or heat loss of the working fluid in the expansion unit 50, thereby reducing energy loss.
In the configuration in which the working fluid supplied from the outside is introduced into the expansion chamber 54 via only the working fluid passage 51e in this way, a liquid-phase working fluid may be introduced into the expansion chamber 54 and thus an internal lubricant may flow away, whereby sliding portions or rotating portions may be lack of lubrication.
In the expansion unit 50 according to this embodiment, the ball-coupling anti-rotation mechanism 56 using balls as rolling members is employed as the structure rotating to prevent the rotation of the orbiting scroll 53 and sliding by receiving a thrust force acting on the orbiting scroll 53. It has been confirmed by experiments that the anti-rotation mechanism 56 does not cause a problem such as seizure even in an insufficient lubrication state and has high durability.
Accordingly, in the expansion unit (scroll-type expander) according to this embodiment, it is possible to achieve both the realization of the simple structure and the reduction in energy loss, as mentioned above, and the securement in high durability and reliability.
In the anti-rotation mechanism 56 according to this embodiment, the predetermined gap C is formed between the outer edge portion including the area having the concave portions 565 formed in the orbiting-side plate 562 and the base 53a of the orbiting scroll 53, so as to allow the elastic deformation of the orbiting-side plate 562. Accordingly, even when a large thrust force is applied to the anti-rotation mechanism 56, it is possible to reduce deformation of the balls 563 and to prevent malfunction of the anti-rotation mechanism 56 or generation of noise.
The present invention is not limited to the above-mentioned embodiment, but may be modified and changed in various forms based on the technical spirit of the present invention. Several modification examples will be described below.
In the above-mentioned embodiment, the working fluid passage 51e formed in the base 51a of the fixed scroll 51 extends substantially in the horizontal direction, but the working fluid passage may be formed substantially in an L shape as illustrated in
In this case, a part from the evaporator 22 of the circulation passage 21 of the working fluid to the expansion unit 50 (expander 23) can be disposed above the expansion unit 50. Accordingly, this configuration is useful, for example, when a lateral space of the expansion unit 50 has no margin or when the space is used for another purpose, and it is possible to enhance a degree of freedom in layout and thus to effectively utilize the space.
In this case, it is more preferable as illustrated in
An anti-rotation mechanism 57 illustrated in
In
In the fixed-side plate 571 and the orbiting-side plate 572, annular race grooves 574 of which the groove cross-section has an arc-like shape are formed at equal intervals in the circumferential direction. The annular race grooves 574 are formed to correspond to the orbiting motion of the orbiting scroll 53.
The balls 573 are rollably arranged between the annular race grooves 574 of the fixed-side plate 571 and the annular race grooves 574 of the orbiting-side plate 572.
When the orbiting scroll 53 moves around, the balls 573 roll along the corresponding annular race grooves 574 and thus the rotation of the orbiting scroll 53 is prevented.
An anti-rotation mechanism 58 illustrated in
In
Both surfaces of each of the fixed race 581 and the orbiting race 583 have a flat ring shape. The fixed ring 582 and the orbiting ring 584 have circular ball receiving portions (through holes) 585 formed at equal intervals in the circumferential direction.
The balls 586 are supported by the fixed race 581 and the orbiting race 583 in a state in which the balls are arranged between the ball receiving portions 585 of the fixed ring 582 and the orbiting ring 584.
When the orbiting scroll 53 moves around, the balls 586 roll along the inner circumferences of the through holes 585 and thus the rotation of the orbiting scroll 53 is prevented. In the anti-rotation mechanism 58, the fixed race 581 corresponds to the fixed-side plate and the orbiting race 583 corresponds to the orbiting-side plate.
These anti-rotation mechanisms 57 and 58 are also ball-coupling anti-rotation mechanisms using balls as rolling members, and it has been confirmed by experiments that the anti-rotation mechanisms do not cause a problem such as seizure even in an insufficient lubrication state and has high durability, similarly to the anti-rotation mechanism 56 according to the above-mentioned embodiment. As a result, as in the above-mentioned embodiment, according to the scroll-type expander, it is possible to achieve both the realization of the simple structure and the reduction in energy loss, as mentioned above, and the securement in high durability and reliability.
The anti-rotation mechanism is not limited to the above-mentioned configurations as long as it is a ball-coupling anti-rotation mechanism using balls as rolling members. For example, an anti-rotation mechanism may be employed which has a configuration in which a ring-like intermediate plate is disposed between the fixed-side plate and the orbiting-side plate, balls are rollably arranged between grooves formed in the fixed-side plate and grooves formed on one surface of the intermediate plate and between grooves formed on the other surface of the intermediate plate and grooves formed in the orbiting-side plate. The end face of the orbiting scroll may be formed to serve as the orbiting-side plate.
In the above-mentioned embodiment, the pump 25 and the expander 23 of the Rankine cycle device 2 are integrated as a unified body to form a pump-integrated expander (fluid machine) 27, but the expander may be used alone. The expander 23 and a power generator of the Rankine cycle device 2 may be integrated as a unified body to form a power-generator-integrated expander (fluid machine). In this case, the power generator is driven with a drive force generated from the expander 23, and electric power generated from the power generator is supplied to, for example, an on-board battery or an on-board electric motor (both are not illustrated).
The configuration of the power-generator-integrated expander will be described below. The elements common to the above-mentioned pump-integrated expander 27 (
As illustrated in
The power generation unit 100 includes a power generator housing 110 and a power generator 120 disposed in the power generator housing 110.
The power generator housing 110 includes a first housing 112 that is open toward the expansion unit 50 and that defines a housing space 111 of the power generator 120 and a second housing 113 that is disposed on the expansion unit 50 side of the first housing 112 and that closes the housing space 111. In the second housing 113, a tubular portion 113a protruding to the expansion unit 50 side is formed. The outer circumferential surface of the tubular portion 113a is fitted to the inner circumferential surface of the small-inner-diameter portion 52b of the expander housing 52.
The power generator 120 includes a rotor 121 that is fixed to the rotating shaft 26 and that is formed of, for example, a permanent magnet and a stator 122 that is fixed to the inner circumferential surface of the first housing 112 so as to surround the rotor 121. The stator 122 includes a yoke 122a and, for example, three sets of coils 122b wound around the yoke 122a, and generates three-phase AC currents with the rotation of the rotor 121.
The rotating shaft 26 extends to pass through the power generator housing 110 (the first housing 112 and the second housing 113) and includes a large-diameter portion 26a at the end on the expansion unit 50 side. The rotating shaft 26 is rotatably supported by a ball bearing 68 disposed on the first housing 112 side and a ball bearing 69 disposed inside the tubular portion 113a of the second housing 113. The other end (the right side in the drawing) of the rotating shaft 26 is connected to the orbiting scroll 53 via the driven crank mechanism 80.
Similarly to the above-mentioned embodiment, the orbiting motion of the orbiting scroll 53 is converted into the rotational motion of the rotating shaft 26 by the driven crank mechanism 80, and thus the power generator 120 is driven to generate electric power. The modification examples of the pump-integrated expander 27 can be applied to the power-generator-integrated expander 90.
1 Waste heat reusing apparatus
2 Rankine cycle device
22 Evaporator
23 Expander
24 Condenser
25 Pump
26 Rotating shaft
27 Pump-integrated expander (fluid machine)
50 Expansion unit (scroll-type expander)
51 Fixed scroll
51
a Base
51
b Scroll portion
51
c Suction port
51
d Inlet
51
e Working fluid passage
51
f Vertical passage
51
g Horizontal passage
51
h Liquid reservoir
52 Expander housing
52
c Stepped face (end face)
53 Orbiting scroll
53
a Base
53
b Scroll portion
54 Expansion chamber
56 to 58 Anti-rotation mechanism
60 Pump unit
90 Power-generator-integrated expander (fluid machine)
100 Power generation unit
561, 571 Fixed-side plate
562, 572 Orbiting-side plate
563, 573 Ball
564, 574 Annular race groove
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-024635 | Feb 2012 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2013/052872 | 2/7/2013 | WO | 00 |
