JP2020020263A - Scroll expander - Google Patents

Abstract

To provide a scroll expander whose volume ratio can be increased without causing an increase in its size, or whose size can be decreased while keeping its volume ratio.SOLUTION: A scroll expander 7 includes: a suction chamber 80 formed near a scroll center part by a first scroll wall 712 of a fixed scroll 71 and a second scroll wall 722 of a movable scroll 72, and whose volume is changed by turning of the movable scroll 72; a fluid passage 73 for guiding working fluid to the suction chamber 80; and a valve device 74 for opening the fluid passage 73 in order to introduce the working fluid to the suction chamber 80, and closing the fluid passage 73 before the suction chamber 80 is partitioned into two expansion chambers.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a scroll expander, and more particularly to a scroll expander suitable for being incorporated in a Rankine cycle.

  A conventional scroll expander is generally configured to repeat the following operation. First, the scroll wall of the fixed scroll and the scroll wall of the movable scroll come into contact with each other near the center of the scroll. Next, the movable scroll was turned and the scroll wall of the movable scroll was moved to form a suction chamber near the center of the scroll, and a high-pressure working fluid such as a superheated vapor refrigerant was provided to the fixed scroll. It is introduced into the suction chamber via the introduction part. The introduction of the working fluid into the suction chamber is continued with the expansion of the suction chamber due to the turning of the movable scroll. Next, when the movable scroll makes one rotation (orbits), and the scroll wall of the fixed scroll and the scroll wall of the movable scroll come into contact again near the center of the scroll, the suction chamber expands two times. It is divided (divided) into a room (closed space). Thereby, the introduction of the working fluid is stopped, and the working fluid introduced into the suction chamber is taken into the two expansion chambers. Next, the taken-in working fluid expands in the two expansion chambers, whereby the orbiting scroll orbits and the two expansion chambers move toward the outer periphery of the scroll while expanding. Then, when the two expansion chambers move to the vicinity of the outer peripheral portion of the scroll and communicate with the discharge port, the expansion of the working fluid is completed, and the working fluid that has expanded to a low pressure in the two expansion chambers is discharged. Discharged from the discharge port.

  In the conventional scroll expander, as described above, the introduction of the working fluid is continued until the suction chamber is divided into the two expansion chambers. Then, basically, the volumes (hereinafter referred to as “discharge volumes”) of the two expansion chambers (at the outer peripheral side of the scroll) communicating with the discharge port and the working fluid (at the center of the scroll) are taken in. The ratio between the volumes of the two expansion chambers (hereinafter referred to as “take-in volumes”), that is, the bottom areas of the two expansion chambers (hereinafter referred to as “bottom areas of discharge volumes”) communicating with the discharge ports and the working fluid are taken in. The ratio to the bottom area of the two expansion chambers (hereinafter referred to as the “bottom area of the intake volume”) is the volume ratio of the scroll expander.

JP 2006-242133 A

  In a conventional scroll expander, the scroll wall is generally formed along an involute curve of a circle, and parameters such as a radius, a thickness, and an opening angle of a base circle of the scroll wall are determined according to an application. It is determined. Then, the bottom area of the intake volume is substantially determined from the determined parameters. For this reason, it is difficult to largely change the bottom area of the intake volume in a scroll expander used for the same kind of application. Further, the bottom area of the discharge volume, in other words, the number of turns of the scroll wall (the outer diameter of the scroll) is determined by the bottom area of the intake volume and the volume ratio required for the scroll expander. The size of the machine (radial size) is almost fixed.

  Therefore, conventionally, in a scroll expander used for the same kind of application, there is a problem that it is difficult to reduce the size while maintaining the volume ratio or to increase the volume ratio without increasing the size. there were. In recent years, scroll expanders have been increasingly required to be smaller and have higher output, and it is desired to be able to respond to such needs.

  Therefore, an object of the present invention is to provide a scroll expander that can increase the volume ratio without increasing the size or reduce the size while maintaining the volume ratio.

  According to one aspect of the present invention, a scroll expander includes a fixed scroll having a first substrate portion and a spiral first scroll wall erected on the first substrate portion, a second substrate portion, and the second substrate. A scroll-shaped second scroll wall erected on the portion, wherein the second scroll wall is disposed so as to mesh with the first scroll wall of the fixed scroll and is rotatable with respect to the fixed scroll. A suction chamber formed near the center of the scroll by the held movable scroll, the first scroll wall and the second scroll wall, and whose volume changes by turning the movable scroll, and guiding a working fluid to the suction chamber. A fluid passage, wherein the suction chamber is divided into two expansion chambers by turning the movable scroll, and the working fluid expands in the two expansion chambers. The movable scroll is further configured to pivot. The scroll expander further includes a valve device that opens the fluid passage for introducing the working fluid into the suction chamber and closes the fluid passage before the suction chamber is partitioned into the two expansion chambers. Including.

  According to the scroll expander, before the suction chamber is divided into the two expansion chambers, the fluid passage is closed by the valve device, and the introduction of the working fluid is stopped. For this reason, compared with the conventional scroll expander in which the introduction of the working fluid is continued until the suction chamber is divided into the two expansion chambers, the bottom area of the intake volume of the working fluid is reduced. be able to. As a result, it is possible to increase the volume ratio of the scroll expander without increasing the size of the scroll expander, or to reduce the size of the scroll expander while maintaining the volume ratio of the scroll expander. .

It is a figure showing the schematic structure of the waste heat recovery equipment to which the scroll expansion machine concerning one embodiment of the present invention was applied. It is a schematic sectional drawing of the said scroll expander. FIG. 3 is an enlarged view of a main part of FIG. 2. It is AA sectional drawing of FIG. It is a perspective view of the rotating body which comprises a valve apparatus. It is a figure for explaining an example of operation of the above-mentioned scroll expander. It is a figure showing the modification of the above-mentioned rotating body. It is a figure which shows the other modification of the said rotating body. It is a figure which shows another modification of the said rotating body. It is a principal part expanded sectional view of the modification of the said scroll expander.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 shows a schematic configuration of a waste heat recovery device 1 to which a scroll expander according to an embodiment of the present invention is applied. The waste heat recovery device 1 is mounted on a vehicle, and is configured to recover and use waste heat of an engine 20 of the vehicle.

  As shown in FIG. 1, the waste heat recovery device 1 includes a Rankine cycle 2, a transmission mechanism 3, and a control unit 4. The engine 20 is a water-cooled engine, and is cooled by engine cooling water circulating in a cooling water circulation path 21. A heater 6 (which will be described later), which is a component of the Rankine cycle 2, is disposed in the cooling water circulation path 21, and engine cooling water that has absorbed heat from the engine 20 (high temperature) passes through the inside of the heater 6. .

  The Rankine cycle 2 is a device that recovers waste heat of the engine 20 from the engine cooling water, converts the waste heat into power (drive power), and outputs the power. The Rankine cycle 2 has a refrigerant circulation path 5 through which a refrigerant as a working fluid circulates. A heater 6, a scroll expander 7, a condenser 8, and a pump 9 are arranged in the refrigerant circulation path 5 in this order along the refrigerant circulation direction. Although not particularly limited, as the working fluid (refrigerant), for example, ethanol, HFC-134a, HFC-245fa, or HFO-1233zd can be used.

  The heater 6 is a heat exchanger that exchanges heat between the engine cooling water that has absorbed heat from the engine 20 (high temperature) and the refrigerant of the Rankine cycle 2. The refrigerant is heated by the engine cooling water when passing through the heater 6, and becomes a high-pressure superheated vapor refrigerant (high-pressure working fluid).

  The scroll expander 7 generates power (driving force) by expanding the superheated vapor refrigerant from the heater 6. As described later, the scroll expander 7 includes a fixed scroll and a movable scroll, and the movable scroll is driven by expanding the superheated vapor refrigerant in an expansion chamber formed between the fixed scroll and the movable scroll. It is configured to be. The driven movable scroll performs a revolving motion, and the revolving motion of the movable scroll is converted into a rotational motion of an output shaft and output as a driving force. Then, the refrigerant (low-pressure working fluid) that has expanded to a low pressure in the expansion chamber is discharged from the scroll expander 7.

  The condenser 8 is a heat exchanger that exchanges heat between the refrigerant discharged from the scroll expander 7, that is, the low-pressure refrigerant and the outside air. When passing through the condenser 8, the low-pressure refrigerant is cooled by outside air and condensed (liquefied). Although not shown, a fan that blows outside air toward the condenser 8 may be provided near the condenser 8.

  The pump 9 is a mechanical pump, and pumps the refrigerant condensed (liquefied) through the condenser 8 by being driven through the drive shaft to the heater 6. When the pump 9 operates, the refrigerant circulates through each element of the Rankine cycle 2, that is, the heater 6, the scroll expander 7, the condenser 8, and the pump 9.

  Here, in the present embodiment, the scroll expander 7 and the pump (mechanical pump) 9 are integrally connected by a rotating shaft 10a to form a pump-integrated expander 10. That is, the rotary shaft 10 a of the pump-integrated expander 10 has a function as the output shaft of the scroll expander 7 and a function as the drive shaft of the pump 9.

  Further, in the present embodiment, the refrigerant circulation path 5 has a bypass path 51 for circulating the refrigerant bypassing the scroll expander 7 and a bypass valve 52 for opening and closing the bypass path 51. The operation of the bypass valve 52, that is, the opening and closing of the bypass passage 51, is controlled by the control unit 4.

  The transmission mechanism 3 transmits power between the engine 20 and the Rankine cycle 2. Specifically, the transmission mechanism 3 transmits the output torque of the engine 20 to (the pump 9 of) the pump-integrated expander 10 and the torque (axial torque) of the pump-integrated expander 10 that is the output of the Rankine cycle 2. ) To the engine 20.

  The transmission mechanism 3 includes a pulley 32 attached to an end of the rotating shaft 10a of the pump-integrated expander 10 via an electromagnetic clutch 31, a crank pulley 33 attached to the crankshaft 22 of the engine 20, a pulley 32, And a belt member 34 wound around the crank pulley 33. When the electromagnetic clutch 31 is turned on (engaged), power is transmitted between the engine 20 and the Rankine cycle 2 (the pump-integrated expander 10), and when the electromagnetic clutch 31 is turned off (released). Power transmission between the engine 20 and the Rankine cycle 2 (the pump-integrated expander 10) is shut off. ON (engagement) / OFF (release) of the electromagnetic clutch 31 is controlled by the control unit 4.

  The control unit 4 controls the operation of the Rankine cycle 2 by controlling the electromagnetic clutch 31 and the bypass valve 52 as follows, for example. When starting the Rankine cycle 2, the control unit 4 opens the bypass valve 52, turns on (engages) the electromagnetic clutch 31, and drives the pump 9 by the engine 20. Thereby, in the Rankine cycle 2, the refrigerant circulates around the scroll expander 7. The control unit 4 closes the bypass valve 52 when, for example, the pressure difference between the front and rear of the scroll expander 7 becomes a predetermined value or more. Accordingly, in the Rankine cycle 2, the refrigerant circulates through the scroll expander 7, and the scroll expander 7 starts generating a driving force by expanding the superheated vapor refrigerant from the heater 6. Thereafter, when the scroll expander 7 generates a sufficient driving force, a part of the driving force generated by the scroll expander 7 drives the pump 9, and the remaining driving force is transmitted to the engine via the transmission mechanism 3. 20 to assist the output (driving force) of the engine 20. Further, when stopping the Rankine cycle 2, the control unit 4 turns off (disengages) the electromagnetic clutch 31 and stops the pump 9 (that is, stops the circulation of the refrigerant). Although not shown, the generator may be driven by the driving force generated by the scroll expander 7, and the power generated by the generator may be stored in a battery or the like. In this case, an electric pump operated by electric power from the battery or the like can be used as the pump 9.

  Next, the scroll expander 7 in the present embodiment, that is, the expander portion of the pump-integrated expander 10 will be described. The description of the pump 9 (the pump portion of the pump-integrated expander 10) is omitted, but the pump 9 is a known mechanical pump (gear pump) having a configuration that can be connected to the scroll expander 7 by a rotating shaft 10a. Or a vane pump).

  2 is a schematic sectional view of the scroll expander 7, FIG. 3 is an enlarged view of a main part of FIG. 2, and FIG. 4 is a sectional view taken along line AA of FIG. As shown in FIGS. 2 to 4, the scroll expander 7 according to the present embodiment includes a fixed scroll 71 and a movable scroll 72.

  The fixed scroll 71 includes a disk-shaped substrate portion (hereinafter, referred to as a “first substrate portion”) 711 and a spiral scroll wall (hereinafter, referred to as a “first scroll portion”) erected on one surface 711 a of the first substrate portion 711. 712). The fixed scroll 71 is formed or fixed to a housing member (not shown) of the scroll expander 7, for example.

  Similar to the fixed scroll 71, the movable scroll 72 includes a disk-shaped substrate portion (hereinafter, referred to as “second substrate portion”) 721, and a spiral scroll wall erected on one surface 721 a of the second substrate portion 721. (Hereinafter, referred to as “second scroll wall”) 722.

  The fixed scroll 71 and the movable scroll 72 are formed of an aluminum-based material such as aluminum or an aluminum alloy, or an iron-based material such as cast iron or steel. The first scroll wall 712 of the fixed scroll 71 and the second scroll wall 722 of the movable scroll 72 are formed along a circular involute curve. The movable scroll 72 is disposed so that the second scroll wall 722 meshes with the first scroll wall 712 of the fixed scroll 71, and is held rotatably with respect to the fixed scroll 71. Specifically, the orbiting scroll 72 can perform a turning motion while maintaining a fixed eccentric distance from the fixed scroll 71.

  In the present embodiment, the center-side start end (hereinafter, referred to as a “first center-side start end”) 712a of the first scroll wall 712 of the fixed scroll 71 and the center-side start end (hereinafter, referred to as “first center-side start end”) of the movable scroll 72. The second center-side starting end 722a) is formed to have an arcuate (semicircular) cross section, and the flat side surfaces of the two substantially face each other (see FIG. 4).

  In the present embodiment, between the other surface 721b of the second substrate portion 721 of the orbiting scroll 72 and a fixed portion (not shown) of the scroll expander 7, an anti-rotation mechanism for preventing the orbiting scroll 72 from rotating. 41 (for example, a ball coupling) are arranged. The orbiting scroll 72 is connected to the rotary shaft 10a of the pump-integrated expander 10 via an eccentric bearing 42 and a driven crank mechanism 43, so that the orbital motion of the orbiting scroll 72 is reduced by the rotation of the rotary shaft 10a. Converted to movement.

  In the fixed scroll 71, a column-shaped concave portion (hole portion) 712 b having substantially the same depth as the height of the first scroll wall 712 is formed on the upper surface of the first center-side start end 712 a of the first scroll wall 712. ing. The center line of the concave portion 712b coincides with the turning center line O of the orbiting scroll 72.

  The internal space of the concave portion 712b is provided outside the scroll expander 7 via a first hole 711c formed in the first substrate portion 711, specifically, on the inlet side of the scroll expander 7 in the refrigerant circulation path 5. It communicates with a passage portion (a passage portion between the heater 6 and the scroll expander 7). In the present embodiment, the first hole 711c is formed so as to penetrate the first substrate 711 in the thickness direction. One end of the first hole 711c is opened on the inner surface of the recess 712b, specifically, on the inner bottom surface of the recess 712b, and the other end of the first hole 711c is connected to the other surface 711b of the first substrate 711. It is open to. However, the present invention is not limited to this, and the first hole portion 711c may be formed such that one end is opened on the inner bottom surface of the concave portion 712b and the other end is opened on the peripheral side surface of the first substrate portion 711. .

  In addition, the internal space of the concave portion 712b is connected to the first scroll wall 712 of the fixed scroll 71 via a second hole 712c formed on the flat side surface of the first center side starting end 712a of the first scroll wall 712. And the second scroll wall 722 of the movable scroll 72 communicates with the suction chamber 80 formed near the center of the scroll. That is, one end of the second hole 712c opens to the inner surface of the recess 712b, specifically, the inner surface of the recess 712b, and the other end of the second hole 712c opens to the suction chamber 80. . In the present embodiment, two second holes 712c are formed side by side in the height direction of the first scroll wall 712. However, the present invention is not limited to this, and one second hole 712c may be provided.

  A rotating body 741 is rotatably accommodated in a concave portion 712b formed on the upper surface of the first center side starting end 712a. That is, the rotating body 741 is arranged on the center line O of the orbiting of the movable scroll 72. FIG. 5 is a perspective view of the rotating body 741. As shown in FIGS. 4 and 5, the rotating body 741 is formed in a cylindrical shape with a bottom, and is accommodated in the concave portion 712b such that the opening end is located on the inner bottom surface side of the concave portion 712b. . Therefore, the outer surface (bottom surface) of the bottom wall of the rotating body 741 faces one surface 721 a of the second substrate portion 721 of the movable scroll 72.

  An opening 741a having an opening area larger than the opening area of the second hole 712c is formed on the peripheral wall of the rotating body 741. In the present embodiment, one opening 741a corresponding to the two second holes 712c is formed in the peripheral wall of the rotating body 741. However, the present invention is not limited to this, and two openings 741a may be formed in the peripheral wall of the rotating body 741 like the second hole 712c.

  In addition, a pin hole 741b is provided at a position on the bottom surface of the rotating body 741 shifted from the center line of the rotating body 741 (= center line of the concave portion 712b = rotating center line O of the movable scroll 72) by the turning radius R of the movable scroll 72. Are formed. The distal end of a drive pin 742 whose base end is fixed to one surface 721a of the second substrate portion 721 of the orbiting scroll 72 is mounted (inserted) into the pin hole 741b.

  The rotating body 741 is rotationally driven in the concave portion 712b via the driving pin 742 by the orbiting of the movable scroll 72. That is, the rotating body 741 is configured to operate in conjunction with the turning of the movable scroll 72. The rotating body 741 closes the second hole 712c when the opening 741a does not overlap the second hole 712c, and rotates when the opening 741a rotates to a position overlapping the second hole 712c. The second hole 712c is configured to be opened.

  When the second hole 712c is opened by the rotating body 741, the first hole 711c and the second hole 712c communicate with each other via the internal space 741c of the rotating body 741. In this case, the superheated vapor refrigerant from the heater 6 flows into the scroll expander 7 from the first hole 711c, passes through the internal space 741c of the rotating body 741 and the second hole 712c, and flows out to the suction chamber 80. I do. That is, the superheated vapor refrigerant is introduced into the suction chamber 80. On the other hand, when the second hole 712c is closed by the rotating body 741, the communication between the first hole 711c and the second hole 712c is interrupted, so that the superheated vapor refrigerant is not introduced into the suction chamber 80. That is, the introduction of the superheated vapor refrigerant into the suction chamber 80 is stopped.

  Therefore, in the present embodiment, the fluid that guides the superheated vapor refrigerant to the suction chamber 80 is mainly provided by the first hole 711c, the internal space 741c of the rotating body 741, the opening 741a of the rotating body 741, and the second hole 712c. A passage 73 is formed. The first hole portion 711c forms an inlet hole through which the superheated vapor refrigerant flows in from the outside, and the second hole portion 712c forms an outlet hole through which the superheated vapor refrigerant flows out to the suction chamber 80. The internal space 741c of 741 and the opening 741a constitute a connecting part connecting the entrance hole and the exit hole. Further, in the present embodiment, a valve device (rotary valve) 74 for opening and closing the fluid passage 73 (the outlet hole) in conjunction with the turning of the movable scroll 72 is mainly constituted by the rotating body 741 and the driving pin 742. ing.

  In the present embodiment, the scroll expander 7 (the movable scroll 72) that is stopped with the fluid passage 73 (the outlet hole) closed by the valve device 74 (the rotator 741) is started. For this reason, a communication path (throttle path) 75 is provided which constantly connects the first hole 711c (the inlet hole) and the second hole 712c (the outlet hole). The communication path 75 is formed by a first groove portion 751 formed on the inner bottom surface of the concave portion 712b and a second groove portion 752 formed on the inner side surface of the concave portion 712b and connected to the first groove portion 751.

  Next, an example of the operation of the scroll expander 7 will be described with reference to FIGS.

  First, as shown in FIG. 6A, the first center-side starting end 712a of the first scroll wall 712 of the fixed scroll 71 and the second center-side starting end 722a of the second scroll wall 722 of the movable scroll 72 are formed. Contact near the center of the scroll. More specifically, the flat side surface of the first center-side start end 712a and the flat side surface of the second center-side start end 722a abut near the scroll center. At this time, the opening 741a of the rotating body 741 is at a position that does not overlap the second hole 712c. Therefore, the valve device 74 closes the second hole 712c, that is, the (the outlet hole of) the fluid passage 73. The second hole 712c is also closed by the flat side surface of the second center-side start end 722a.

  As described above, the first hole 711c (the inlet hole) and the second hole 712c (the outlet hole) are always in communication with each other through the communication passage 75. Therefore, when the superheated vapor refrigerant is supplied from the heater 6 to the scroll expander 7, the second center-side start end 722a of the second scroll wall 722 of the movable scroll 72 receives the pressure of the superheated vapor refrigerant. Thereby, as shown in FIG. 6B, the orbiting scroll 72 turns and the second scroll wall 722 (the second center side start end 722a) moves, and the first scroll wall 712 and the second scroll wall 712. 722 forms the suction chamber 80 near the center of the scroll. In addition, with the turning of the movable scroll 72, the opening 741a of the rotating body 741 moves to a position overlapping the second hole 712c. Therefore, the valve device 74 opens the second hole portion 712c, that is, the (the outlet hole of) the fluid passage 73. Thereby, the superheated vapor refrigerant is introduced into the suction chamber 80 via the fluid passage 73. That is, introduction of the superheated vapor refrigerant into the suction chamber 80 is started.

  When the superheated vapor refrigerant is introduced into the suction chamber 80, the orbiting scroll 72 turns, the second scroll wall 722 moves, and the suction chamber 80 expands (the volume of the suction chamber 80 increases). Further, the valve device 74 maintains the open state of the second hole portion 712c, that is, (the outlet hole of) the fluid passage 73. Therefore, the expansion of the suction chamber 80 and the introduction of the superheated vapor refrigerant into the suction chamber 80 are continued (FIGS. 6C and 6D).

  Thereafter, when the movable scroll 72 turns to a predetermined angle from the state shown in FIG. 6A, the opening 741a of the rotating body 741 moves to a position where it does not overlap the second hole 712c, and the valve device 74 The second hole 712c, that is, (the outlet hole of) the fluid passage 73 is closed (FIG. 6E). As a result, the introduction of the superheated vapor refrigerant into the suction chamber 80 is stopped, and the suction chamber 80 is closed to form an expansion chamber 80 '. The volume of the suction chamber 80 (expansion chamber 80 ') at this time becomes the intake volume of the scroll expander 7, and the bottom area of the suction chamber 80 (expansion chamber 80') at this time is equal to the bottom area of the intake volume. Become.

  Even after the introduction of the superheated vapor refrigerant into the suction chamber 80 is stopped, the superheated vapor refrigerant already introduced (taken) into the suction chamber 80 (expansion chamber 80 ') expands. As a result, the turning of the movable scroll 72 is continued (FIG. 6F).

  Then, when the orbiting scroll 72 makes one rotation (orbit) and returns to the state shown in FIG. 6A, the suction chamber 80 formed near the center of the scroll is the first expansion chamber, which is two sealed spaces. It is partitioned (divided) into 81 and a second expansion chamber 82. More specifically, the suction chamber 80 becomes an expansion chamber 80 ′, which is one closed space by closing the fluid passage 73 by the valve device 74, and thereafter, the orbiting of the movable scroll 72 due to the expansion of the superheated steam refrigerant. It is divided into a first expansion chamber 81 and a second expansion chamber 82 which are the two closed spaces. At this time, the superheated vapor refrigerant introduced into the suction chamber 80, in other words, the superheated vapor refrigerant introduced into the expansion chamber 80 'is introduced into each of the first expansion chamber 81 and the second expansion chamber 82.

  The superheated vapor refrigerant taken into each of the first expansion chamber 81 and the second expansion chamber 82 expands in the first expansion chamber 81 and the second expansion chamber 82. As a result, the orbiting scroll 72 further turns, and the first expansion chamber 81 and the second expansion chamber 82 move toward the outer periphery of the scroll while expanding.

  When the first expansion chamber 81 and the second expansion chamber 82 move to the vicinity of the outer peripheral portion of the scroll and communicate with a discharge port (not shown), the superheated steam refrigerant in the first expansion chamber 81 and the second expansion chamber 82 is formed. When the expansion of the refrigerant is completed, the refrigerant that has been reduced in pressure by expanding in the first expansion chamber 81 and the second expansion chamber 82 is discharged from the discharge port. The (low-pressure) refrigerant discharged from the discharge port flows toward the condenser 8.

  The scroll expander 7 converts the expansion of the superheated vapor refrigerant into a revolving motion of the movable scroll 72 by repeating the above operation. Then, as described above, the orbiting motion of the orbiting scroll 72 is converted into the rotational motion of the rotating shaft 10a by the eccentric bearing 42 and the driven crank mechanism 43 and the like.

  As described above, the scroll expander 7 according to the present embodiment includes the fluid passage 73 that guides the superheated vapor refrigerant (working fluid) from the heater 6 to the suction chamber 80, and the valve device 74 that opens and closes the fluid passage 73. And The valve device 74 opens the fluid passage 73 for introducing the superheated vapor refrigerant into the suction chamber 80, and the suction chamber 80 is divided into two expansion chambers (a first expansion chamber 81 and a second expansion chamber 82). Before the cooling, the fluid passage 73 is closed to stop the introduction of the superheated vapor refrigerant (FIGS. 6B and 6E).

  Here, as described above, in the scroll expander 7 according to the present embodiment, the bottom area of the suction chamber 80 (expansion chamber 80 ') when the introduction of the superheated vapor refrigerant into the suction chamber 80 is stopped is reduced. The bottom area of the intake volume, which is smaller than the bottom areas of the two expansion chambers (the first expansion chamber 81 and the second expansion chamber 82). For this reason, in the scroll expander 7 according to the present embodiment, the superheated vapor refrigerant is compared with the conventional scroll expander in which the introduction of the working fluid is continued until the suction chamber is divided into two expansion chambers. The bottom area of the intake volume can be reduced. This means that the volume ratio can be increased without changing the bottom area of the discharge volume (and the intake volume), and that the bottom area of the discharge volume can be reduced without changing the volume ratio (and the intake volume) ( That is, the number of turns (the outer diameter of the scroll) of the scroll wall can be reduced. Therefore, according to the scroll expander 7 according to the present embodiment, it is possible to increase the volume ratio without increasing the size (particularly, the size in the radial direction), or to maintain the volume ratio while maintaining the volume ratio (particularly, in the radial direction). Size) can be reduced. As a result, the scroll expander 7 according to the present embodiment can achieve a higher volume ratio than a conventional scroll expander of substantially the same size used for the same kind of use, or is used for the same kind of use. The size can be reduced as compared with a conventional scroll expander that realizes substantially the same volume ratio.

  Here, most of the conventional scroll expanders are configured such that one of the two expansion chambers is hermetically sealed before the other expansion chamber and / or immediately before being partitioned into the two expansion chambers. In the suction chamber, there is a difference between the flow resistances to the areas corresponding to the two expansion chambers, and the volume of the working fluid taken into the two expansion chambers (and, consequently, the pressure of the two expansion chambers) differs. Had occurred. In this regard, in the scroll expander 7 according to the present embodiment, the fluid passage 73 is closed by the valve device 74 before the suction chamber 80 is divided into two expansion chambers (the first expansion chamber 81 and the second expansion chamber 82). Have been. Therefore, the two expansion chambers (the first expansion chamber 81 and the second expansion chamber 82) are sealed almost simultaneously. In each stage of the process of dividing the suction chamber 80 into the first expansion chamber 81 and the second expansion chamber 82, the area corresponding to the first expansion chamber 81 and the area corresponding to the second expansion chamber 82 have the same shape ( (A symmetrical shape), and there is almost no difference between the flow resistance to the area corresponding to the first expansion chamber 81 and the flow resistance to the area corresponding to the second expansion chamber 82. Therefore, according to the scroll expander 7 according to the present embodiment, the superheated vapor refrigerant is taken into the two expansion chambers (the first expansion chamber 81 and the second expansion chamber 82) in a well-balanced manner, and the space between the two expansion chambers is increased. Is also suppressed. As a result, the scroll expander 7 according to the present embodiment can operate more stably and efficiently than the conventional scroll expander.

  Further, in the present embodiment, the valve device 74 opens and closes the fluid passage 73 in conjunction with the turning of the movable scroll 72, specifically, the second hole 712c (a part of the fluid passage 73). The outlet hole is opened and closed. For this reason, opening the fluid passage 73 at an appropriate timing to introduce the superheated vapor refrigerant into the suction chamber 80, closing the fluid passage 73 at an appropriate timing to stop the introduction of the superheated vapor refrigerant, and In addition, it is possible to suppress variations in the volume of the superheated vapor refrigerant taken into the two expansion chambers.

  In particular, the valve device 74 includes a rotating body 741 rotatably housed in a concave portion 712b formed on the upper surface of the first center-side starting end 712a, and the rotating body 741 rotates in conjunction with the turning of the movable scroll 72. Thereby, it is configured to open and close the second hole 712c (that is, the outlet hole of the fluid passage 73), one end of which is opened on the inner side surface of the concave portion 712b. Specifically, the rotating body 741 (and the concave portion 712b) is disposed on the rotation center line O of the movable scroll 72, and the rotating body 741 is rotated in the concave portion 712b by a driving pin 742 fixed to the movable scroll 72. Driven. Therefore, the provision of the valve device 74 prevents the scroll expander 7 from increasing in size, and does not require a drive source for the valve device 74 (the rotator 741). Further, by adjusting the size of the opening 741a to adjust the timing of closing the fluid passage 73, the bottom area of the intake volume is adjusted, and the scroll (especially the size in the radial direction) is not enlarged. It is also possible to adjust the volume ratio of the expander 7.

  In the above-described embodiment, the heater 6 is configured to cause heat exchange between the engine cooling water and the refrigerant of the Rankine cycle 2. However, it is not limited to this. The heater 6 may be configured to cause heat exchange between the exhaust gas of the engine 20 and the refrigerant of the Rankine cycle 2. The exhaust of the engine 20 is higher in temperature than the engine cooling water, and a larger temperature difference is obtained in the Rankine cycle 2, so that the output of the Rankine cycle 2 increases. Although illustration is omitted, in this case, the exhaust of the engine 20 is configured to pass through the heater 6 instead of the engine cooling water.

  When the heater 6 is configured to cause heat exchange between the exhaust gas of the engine 20 and the refrigerant of the Rankine cycle 2, ethanol is used as a suitable refrigerant based on characteristic values (critical temperature, critical pressure, etc.). Can be selected. However, ethanol may corrode the aluminum-based material. For this reason, when ethanol is selected as the refrigerant, the scroll expander 7 uses the fixed scroll 71 and the movable scroll 72 formed of the iron-based material.

  The fixed scroll 71 and the movable scroll 72 formed from the iron-based material are heavier than those formed from the aluminum-based material. In addition, when the weight of the fixed scroll 71 and the movable scroll 72 increases, even if the number of turns of the scroll wall (the outer diameter of the scroll) is the same, the number of parts for balancing and the shape for securing the strength increase, and / or the like. Alternatively, the size of the scroll expander 7 is increased as a result.

  Therefore, the fixed scroll 71 and the movable scroll 72 formed of the iron-based material have a higher necessity to reduce the number of turns (the outer diameter of the scroll) of the scroll wall than those formed of the aluminum-based material. I can say. In this regard, as described above, the scroll expander 7 according to the present embodiment can reduce the number of turns (scroll outer diameter) of the scroll wall without changing the volume ratio. This is particularly effective when the formed fixed scroll 71 and movable scroll 72 are used.

  In the above-described embodiment, the rotating body 741 is configured to be rotationally driven by a driving pin 742 fixed to the movable scroll 72. However, it is not limited to this. As shown in FIG. 7, the rotating body 741 has a pin member 741 d protruding toward one surface 721 a of the second substrate portion 721 of the movable scroll 72 instead of the pin hole 741 b, and A pin hole (not shown) into which the tip of the pin member 741d is mounted (inserted) may be provided on one surface 721a of the two substrate portion 721 instead of the drive pin 742. That is, the rotating body 741 only needs to be configured to be rotationally driven via the pin portion (the driving pin 742, the pin portion 741d) connecting the movable scroll 72 and the rotating body 741.

  Further, in the above-described embodiment, a communication passage 75 is provided that constantly connects the first hole 711c (the inlet hole) and the second hole 712c (the outlet hole). However, it is not limited to this. The communication passage 75 does not always require the first hole 711c and the second hole 712c to always communicate with each other, and at least when the valve device 74 closes the fluid passage 73, the first hole 711c and the second hole What is necessary is just to make it communicate with the part 712c.

  For example, as shown in FIG. 8, a groove 741e extending from one end to the other end in the circumferential direction of the opening 741a is formed on the outer surface of the peripheral wall of the rotating body 741. In this case, a communication path 75 is formed by the internal space 741c of the rotating body 741 and the groove 741e, and the formed communication path 75 is connected to the first hole 711c and the first hole 711c when the valve device 74 closes the fluid path 73. The two holes 712c are communicated. Alternatively, as shown in FIG. 9, a plurality of through holes 741f are formed in the peripheral wall of the rotating body 741 instead of the grooves 741e. In this case, a communication passage 75 is formed by the internal space 741c of the rotating body 741 and at least one of the plurality of through holes 741f, and the formed communication passage 75 is formed when the valve device 74 closes the fluid passage 73. The one hole 711c and the second hole 712c are communicated. Although not shown, the first hole portion 711c and the second hole portion are formed by the gap between the outer surface of the peripheral wall of the rotating body 741 and the inner surface of the concave portion 712b and the internal space 741c of the rotating body 741. A communication path 75 that constantly communicates with the 712c may be formed.

  Furthermore, in the above-described embodiment, the second hole portion 712c that constitutes the outlet hole of the fluid passage 73 is located at an intermediate position in the height direction on the flat side surface of the first center-side starting end portion 712a of the first scroll wall 712. The opening 741a of the rotator 741 is formed at an intermediate position in the height direction of the peripheral wall of the rotator 741 so as to correspond to this position. However, it is not limited to this. As shown in FIG. 10, instead of the second hole 712 c at the first center side start end 712 a of the first scroll wall 712, a concave portion 712 b is formed on the upper surface of the first center side start end 712 a of the first scroll wall 712. A groove 712d extending from the inner side surface to the flat side surface of the first center-side starting end 712a may be formed. In this case, in the rotating body 741, instead of the opening 741a, a cutout portion 741g in which a part of the bottom wall and a part of the peripheral wall of the rotating body 741 are cut out is formed. The fluid passage 73 is formed mainly by the first hole 711c, the internal space 741c of the rotating body 741, the cutout 741g of the rotating body 741, and the groove 712d. The groove 712d forms the outlet hole of the fluid passage 73. Even in this case, the same effect as in the above-described embodiment can be obtained.

  Note that the above-described modifications can be applied in appropriate combinations.

  As described above, the embodiments of the present invention and the modifications thereof have been described. However, the present invention is not limited to the above-described embodiments and the modifications, and further modifications and changes are possible based on the technical idea of the present invention. It is.

  7: scroll expander, 71: fixed scroll, 72: movable scroll, 73: fluid passage, 74: valve device, 75: communication passage, 80: suction chamber, 80 ': expansion chamber, 81: first expansion chamber, 82 ... Second expansion chamber, 711 ... Fixed scroll substrate portion, 711c ... First hole portion (entrance hole), 712 ... Fixed scroll scroll wall (First scroll wall), 712a ... Center end portion of first scroll wall , 712b: concave portion, 712c: second hole portion (exit hole), 712d: groove portion (exit hole), 721: movable scroll substrate portion, 722: movable scroll scroll wall (second scroll wall), 722a: second Central end of scroll wall, 741 ... rotating body, 741a ... opening, 741b ... pin hole, 741c ... internal space of rotating body, 741d ... pin member (pin section), 742 ... drive pin (Pin portion)

Claims (6)

A fixed scroll having a first substrate portion and a spiral first scroll wall erected on the first substrate portion;
A second scroll portion provided upright on the second substrate portion and the second scroll portion, the second scroll wall being disposed so as to mesh with the first scroll wall of the fixed scroll; A movable scroll held rotatably with respect to the fixed scroll,
A suction chamber formed in the vicinity of the center of the scroll by the first scroll wall and the second scroll wall, the volume of which changes with the turning of the movable scroll;
A fluid passage for guiding a working fluid to the suction chamber;
Including
A scroll expander configured such that the suction chamber is divided into two expansion chambers by turning the movable scroll, and the movable scroll further turns by expanding the working fluid in the two expansion chambers. ,
A valve device that opens the fluid passage for introducing the working fluid into the suction chamber and closes the fluid passage before the suction chamber is partitioned into the two expansion chambers;
Scroll expander.   The scroll expander according to claim 1, wherein the valve device is configured to open and close the fluid passage in conjunction with the turning of the movable scroll. The fluid passage is formed at an inlet hole formed in the first substrate portion of the fixed scroll and through which the working fluid flows from the outside, and at a side surface of a center-side start end of the first scroll wall of the fixed scroll. An outlet hole in which the working fluid flowing from the inlet hole flows out to the suction chamber,
The valve device is configured to open and close the outlet hole of the fluid passage in conjunction with the turning of the movable scroll,
The scroll expander according to claim 2. A recess is formed on the upper surface of the center-side start end of the first scroll wall of the fixed scroll, and one end of the inlet hole and one end of the outlet hole are respectively opened on the inner surface of the recess. ,
The valve device includes a rotating body rotatably housed in the recess, and is configured as a rotary valve that opens and closes the outlet hole by rotating the rotating body in conjunction with turning of the movable scroll.
The scroll expander according to claim 3.   The scroll expander according to claim 4, wherein the rotating body is disposed on a center line of rotation of the movable scroll, and is rotationally driven via a pin member that connects the movable scroll and the rotating body.   The scroll according to any one of claims 3 to 5, further comprising a communication path that connects the inlet hole and the outlet hole when at least the valve device closes the outlet hole of the fluid passage. Expander.