JP2007239588A - Multi-stage rotary fluid machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-stage rotary fluid machine in which a pressure loss when a working fluid moves from a first cylinder to a second cylinder is small. <P>SOLUTION: An expander 100 is of a two-stage rotary type comprising the first cylinder 105 and the second cylinder 106. A communication hole 104b allowing a discharge side operating chamber 115b between the first cylinder 105 and the second cylinder 109 to communicate with a suction side operating chamber 116a between the second cylinder 106 and a second piston 110 and used to feed a refrigerant from the first operating chamber 115b to the second operating chamber 116a is formed in an intermediate plate 104 partitioning the first cylinder 105 from the second cylinder 106. The shape and position of the communication hole 104b are so set that a part of the opening edge on the first cylinder 105 side forms a part of a virtual circle having a diameter of equal to or larger than d<SB>1</SB>and less than D<SB>1</SB>which is inscribed in the first cylinder 105 at a first angular position and extends in the direction opposite to the rotating direction of the first piston 109 from the first angular position. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a multistage rotary fluid machine represented by a compressor and an expander such as a refrigerator-freezer and an air conditioner.

  A power recovery type refrigeration cycle apparatus has been proposed in which the expansion energy of the refrigerant is recovered by an expander and the recovered energy is used as part of the work of the compressor. For example, as an expander applied to such a refrigeration cycle apparatus, a two-stage rotary expander as shown in Japanese Patent Application Laid-Open No. 2005-106046 has been studied.

10A and 10B are cross-sectional views of a conventional two-stage rotary expander 200. FIG. FIG. 10A shows the first-stage cylinder 205 (first cylinder), and FIG. 10B shows the second-stage cylinder 206 (second cylinder). The refrigerant sucked into the first cylinder 205 is an expansion chamber constituted by the working chamber 215b of the first cylinder 205, the working chamber 216a of the second cylinder 206, and a communication hole 204a communicating the both working chambers 215b and 216a. Inflates with. The first cylinder 205 and the second cylinder 206 are partitioned by an intermediate plate, and a communication hole 204a is formed so as to penetrate the intermediate plate in the thickness direction. If such a structure is adopted, the working chamber for sucking the refrigerant, the working chamber for expanding the refrigerant, and the working chamber for discharging the refrigerant can be easily partitioned, and at the same time, the working chamber on the suction side is 360 ° continuous. Inhalation is possible, and inhalation pulsation can be reduced.
JP 2005-106046 A

  In the two-stage rotary expander 200 as described above, the cross-sectional shape of the communication hole 204a that connects the working chamber 215b of the first cylinder 205 and the working chamber 216a of the second cylinder 206 is usually circular. Hereinafter, the operation of the circular communication hole 204a will be described with reference to FIGS. 11A to 11D. 11A to 11D show a communication state between the working chamber 215b of the first cylinder 205 and the communication hole 204a when the shaft 203 rotates counterclockwise.

  FIG. 11A shows a moment when the working chamber 215b of the first cylinder 205 and the communication hole 204a communicate with each other. The communication between the working chamber 215b of the first cylinder 205 and the working chamber 216a of the second cylinder 206 starts by gradually opening the communication hole 204a from the closed state as the shaft 203 rotates. When the communication hole 204a is circular, at the moment when the working chamber 215b of the first cylinder 205 and the communication hole 204a communicate with each other, the contact P between the communication hole 204a and the first cylinder 205 is replaced by the first piston 209 and the first cylinder 205. This is the moment that coincides with the contact point Q.

  FIG. 11B shows a state in which the shaft 203 has rotated 20 ° after the working chamber 215b and the communication hole 204a communicate with each other. FIG. 11C shows a state in which the shaft 203 is rotated by 40 ° after the working chamber 215b and the communication hole 204a communicate with each other. FIG. 11D shows a state in which the shaft 203 is rotated by 60 ° after the working chamber 215b and the communication hole 204a communicate with each other. In each figure, the communication portion is indicated by hatching.

  In FIG. 12, the rotation angle of the shaft 203 and the first piston 209 in the communication hole 204a overlap with the time point when the communication between the working chamber 215b of the first cylinder 205 and the working chamber 216a of the second cylinder 206 starts. It is a graph which shows the relationship with the ratio of the area (henceforth a communication area) of the part which is not. As can be understood from FIGS. 11A to 11D and FIG. 12, the communication area is the opening of the communication hole 204a when the shaft 203 is rotated by 20 ° after the working chamber 215b of the first cylinder 205 and the communication hole 204a communicate. It is about 1.3% of the area, and even when the shaft 203 is rotated by 40 °, it is less than 10%, and the communication area does not increase easily.

  Generally, when an expander is introduced into a thermal home appliance, the capacity of the working chamber of the expander is preferably 1 cc or less because of its capability. Specifically, the inner diameter of the first cylinder 205 is of the order of 20 to 40 mm, and the diameter of the communication hole 204a is about 3 to 4 mm. Therefore, after the working chamber 215b and the communication hole 204a communicate with each other, the refrigerant leaks from the working chamber 215b into the communication hole 204a through the minute gap until the shaft 203 rotates about 30 ° to 40 °. .

  Further, in the conventional two-stage rotary expander 200, at the moment when the working chamber 215b and the communication hole 204a communicate with each other, the pressure of the refrigerant on the working chamber 215b side is equal to the suction pressure and is high. The pressure of the refrigerant is equal to the discharge pressure and is low. For example, when the refrigerant is carbon dioxide, the pressure difference reaches 50 atmospheres. When a working fluid is allowed to flow through a minute gap in a state where such a large differential pressure exists, a large fluid resistance is generated and the pressure loss of the working fluid becomes significant. The expansion of the pressure loss is a problem that directly leads to a reduction in expansion energy recovery efficiency. Such problems can occur not only in a two-stage rotary expander but also in other multi-stage rotary fluid machines such as a two-stage rotary compressor.

  In view of the above problems, an object of the present invention is to provide a multi-stage rotary fluid machine having a small pressure loss when a working fluid (refrigerant) moves from a first cylinder to a second cylinder.

That is, the present invention
A first cylinder;
A shaft that penetrates the inside and outside of the first cylinder;
A first piston attached to the shaft and rotating eccentrically in the first cylinder;
A second cylinder arranged concentrically with the first cylinder in a shared shaft;
A second piston attached to the shaft and rotating eccentrically in the second cylinder;
A first partition member that is movably mounted in a first groove formed in the first cylinder and partitions a space between the first cylinder and the first piston into a first suction side space and a first discharge side space;
A second partition member that is movably mounted in a second groove formed in the second cylinder, and divides a space between the second cylinder and the second piston into a second suction side space and a second discharge side space;
A communication hole that communicates the first discharge side space and the second suction side space to form one working chamber, and includes a middle plate that separates the first cylinder and the second cylinder;
When the outer diameter of the first piston is defined as d ₁ and the inner diameter of the first cylinder is defined as D ₁ ,
In the communication hole, a part of the opening edge on the first cylinder side forms a part of a virtual circle having a diameter d ₁ or more and less than D ₁ inscribed in the first cylinder at the first angle position. Provided is a multistage rotary fluid machine whose shape and position are set so as to extend in a direction opposite to the rotation direction of one piston.

  In another aspect of the present invention, the communication hole is shaped so that a part of the opening edge on the first cylinder side is along the inner peripheral surface of the first cylinder in a direction parallel to the rotation axis of the shaft. And position are set.

  According to the multistage rotary fluid machine of the present invention, the communication area between the first discharge side space of the first cylinder and the communication hole is rapidly increased from the beginning of communication compared to at least the case where the communication hole is circular. To come. That is, since the time required for the working fluid to pass through the minute gap can be shortened, the pressure loss of the working fluid can be reduced, which contributes to higher efficiency of the multistage rotary fluid machine.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. A rotary fluid machine represented by a rotary expander or a rotary compressor is subdivided into a rolling piston system or a swing system, but the present invention can be applied to either of them. In this specification, a rolling piston system will be described as an example.

(First embodiment)
FIG. 1 is a longitudinal sectional view showing a configuration of a two-stage rotary expander that is an embodiment of the present invention. 2A is an X1-X1 cross-sectional view of the two-stage rotary expander of FIG. 1, and FIG. 2B is an X2-X2 cross-sectional view. A two-stage rotary expander 100 shown in FIG. 1 includes a sealed container 102, a generator 101, and an expansion mechanism section 120.

  The generator 101 includes a stator 101 a fixed to the hermetic container 102, a shaft 103, and a rotor 101 b fixed to the shaft 103.

  The expansion mechanism 120 includes an upper bearing member 107, a first cylinder 105, an intermediate plate 104, a second cylinder 106, a lower bearing member 108, a first piston 109, a second piston 110, a first vane 111, a second vane 112, The first spring 113, the second spring 114, and the shaft 103 are provided, and a so-called two-stage rotary type configuration is provided. The shaft 103 is shared with the generator 101, passes through the first cylinder 105 and the second cylinder 106 that are separated from each other by the intermediate plate 104, and is freely rotatable by the upper bearing member 107 and the lower bearing member 108. It is supported by. The shaft 103 is provided with a first eccentric portion 103a and a second eccentric portion 103b so as to protrude outward in the radial direction. A ring-shaped first piston 109 disposed inside the first cylinder 105 is fitted into the first eccentric portion 103a. A second piston 110 disposed inside the second cylinder 106 is fitted to the second eccentric portion 103b.

  As shown in FIG. 2A, the first cylinder 105 is formed with a first vane groove 105a. A first vane 111 is slidably mounted in the first vane groove 105a, in other words, can move forward and backward in the longitudinal direction. The first spring 113 is disposed on the back side of the first vane 111, and has one end contacting the first cylinder 105 and the other end contacting the first vane 111 to press the first vane 111 against the first piston 109. ing. Further, as shown in FIG. 2B, the second cylinder 106 is formed with a second vane groove 106a. A second vane 112 is slidably mounted in the second vane groove 106a, in other words, can be moved back and forth in the longitudinal direction. The second spring 114 is disposed on the back side of the second vane 112, and has one end in contact with the second cylinder 106 and the other end in contact with the second vane 112 to press the second vane 112 against the second piston 110. ing.

  The crescent-shaped space formed by the first cylinder 105 and the first piston 109 is divided into a first suction-side working chamber 115a which is a suction-side working chamber by a first vane 111 which is a partition member, and a discharge-side working chamber. It is partitioned off from a first discharge side working chamber 115b. The crescent-shaped space formed by the second cylinder 106 and the second piston 110 is divided into a second suction side working chamber 116a which is a suction side working chamber by a second vane 112 which is a partition member, and a discharge side operation. It is partitioned into a second discharge side working chamber 116b which is a chamber. The total volume of the second suction side working chamber 116a and the second discharge side working chamber 116b is larger than the total volume of the first suction side working chamber 115a and the first discharge side working chamber 115b.

  A suction hole 105b formed in the first cylinder 105 communicates with the first suction side working chamber 115a. In addition, a communication hole 104b is formed in the intermediate plate 104 so as to penetrate in the thickness direction, and the first discharge side working chamber 115b of the first cylinder 105 and the second cylinder 106 have a first shape through the communication hole 104b. The two suction side working chambers 116a communicate with each other to form one space, that is, an expansion chamber. Further, the discharge hole 106b formed in the second cylinder 106 communicates with the second discharge side working chamber 116b.

The inner diameter D ₁ of the first cylinder 105 is equal to the inner diameter D ₂ of the second cylinder 106. Further, the first cylinder 105 and the second cylinder 106 are arranged concentrically. However, the arrangement position of the first vane 111 around the rotation axis O of the shaft 103 is similarly shifted from the arrangement position of the second vane 112 by a predetermined angle, for example, several tens of degrees. Further, the first eccentric portion 103 a and the second eccentric portion 103 b of the shaft 103 are different in the direction of projecting around the rotation axis O of the shaft 103. This difference in the protruding direction coincides with the angular difference between the first vane 111 and the second vane 112. That is, the timing at which the first piston 109 arrives at the top dead center (position where the first vane 111 is pushed up most) and the timing at which the second piston 110 arrives at the top dead center (position where the first vane 112 is pushed up most) are Match. Such a configuration can smoothly increase the volume of the expansion chamber formed by the first discharge side working chamber 115b of the first cylinder 105 and the second suction side working chamber 116a of the second cylinder 106. Maximize 100 recovery power. The communication hole 104b is formed in the intermediate plate 104 so as to extend from the first cylinder 105 toward the second cylinder 106 in an angular region sandwiched between the first vane 111 and the second vane 112. . With such a configuration, the length of the communication hole 104b in the direction parallel to the rotation axis O of the shaft 103 can be minimized, and the pressure loss when the refrigerant (working fluid) passes through the communication hole 104b. Can be reduced. However, as will be described later, the first vane 111 and the second vane 112 may be positioned at the same angle with respect to the rotation axis O.

Next, the operation of the expander 100 will be described.
The high-pressure refrigerant is sucked into the first suction side working chamber 115a of the first cylinder 105 from the suction pipe 117 shown in FIG. 2A through the suction hole 105b. With the rotational movement of the shaft 103, the volume of the first suction side working chamber 115a expands, and eventually the state shifts to the first discharge side working chamber 115b, and the suction stroke ends. The high-pressure refrigerant moves from the first discharge side working chamber 115b of the first cylinder 105 to the second suction side working chamber 116a of the second cylinder 106 through the communication hole 104b. Accordingly, the volume of the entire working chamber communicated with the communication hole 104b increases, that is, the volume of the first discharge side working chamber 115b of the first cylinder 105 decreases, and the second suction side operation of the second cylinder 106 occurs. The shaft 103 rotates in the direction in which the volume of the chamber 116a increases, and the generator 101 is driven. As the shaft 103 rotates, the first discharge side working chamber 115b of the first cylinder 105 disappears. The second suction side working chamber 116a of the second cylinder 106 moves to the second discharge working chamber 116b communicating with the discharge hole 106b, and the expansion stroke ends. Then, the low-pressure refrigerant is discharged from the discharge hole 106b to the discharge pipe 118.

FIG. 3A shows an enlarged view of the communication hole 104b on the first cylinder 105 side. FIG. 3A shows the positional relationship between the first vane 111, the first piston 109, and the communication hole 104b in the state where the first vane 111 is pushed out most, that is, at the bottom dead center. On the first cylinder 105 side, the communication hole 104 b has a maximum opening width in the circumferential direction of the first cylinder 105 that is larger than a maximum opening width in the direction toward the rotation axis O of the shaft 103. Specifically, a part of the opening edge of the communication hole 104b (opening edge H ₁ I ₁ ) is an imaginary circle having a diameter less than the inner diameter D ₁ of the first cylinder 105 and the outer diameter d ₁ of the first piston 109 or more. The arc-shaped opening edge H ₁ I ₁ is adjacent to the inner peripheral surface of the first cylinder 105. By forming the communication hole 104b having such an opening shape and position, the communication area between the first discharge side working chamber 115b of the first cylinder 105 and the communication hole 104b is rapidly increased from the initial communication.

Next, a procedure for determining the shape and position of the communication hole 104b will be described.
First, as shown in FIG. 3A, the inner diameter of the center O ₁ of the first cylinder 105, draws a virtual line toward the H ₁ point where the first cylinder 105 and the side surface of the first vane groove 105a intersects. The inner diameter center O ₁ of the first cylinder 105 coincides with the rotation axis O of the shaft 103. Next, a virtual circle having a center on the line segment O ₁ H ₁ , the same diameter as the outer diameter d ₁ of the first piston 109, and inscribed at the point H ₁ (first angular position) with the first cylinder 105. Draw. A part of the virtual circle extending from the point H _{1 in} the direction opposite to the rotation direction of the first piston 109 (clockwise in FIG. 3A) is set as the opening edge H ₁ I ₁ of the communication hole 104b. That is, when the first piston 109 is in contact with the first cylinder 105 at the point H ₁ , the opening edge H ₁ I ₁ of the communication hole 104 b coincides with the outer peripheral edge of the first piston 109. By aligning the opening edge H ₁ I ₁ of the communication hole 104b with the outer peripheral edge of the first piston 109, the communication between the first discharge side working chamber 115b of the first cylinder 105 and the communication hole 104b can be made smooth.

For the opening edge H ₁ I ₁ opening edge I ₁ J _{1 except, J 1 K 1, K 1} H 1 of the communication hole 104b, can be set somewhat arbitrarily. In the present embodiment, settings are made as follows. That is, the point I ₁ is set so that the angle of the opening edge H ₁ I ₁ is 20 °, and then a virtual line is drawn from the point I ₁ toward the inner diameter center O ₁ of the first cylinder 105, and on this virtual line Set the opening edge I ₁ J ₁ . Moreover, from the point H ₁ along the longitudinal direction of the first vane 111 drawn an imaginary line (which is also the extension of the first vane groove 105a), setting the opening edge H ₁ K ₁ to the virtual line. Further, a virtual circle centered on the point O ₁ is drawn so that the opening area of the communication hole 104b is equal to the circular communication hole 204a (see FIG. 11A) shown in the conventional example, and the points J ₁ and K ₁ are drawn. Set. However, the opening edge J ₁ K ₁ is not necessarily a curve, and can be set as appropriate so that the opening area of the communication hole 104b can be easily adjusted, for example, a straight line.

In the present embodiment, the communication hole 104b is such that a part of the opening edge H ₁ K ₁ on the first cylinder 105 side is along the movable range of the first vane 111 (the range in which the first vane 111 can operate). The shape and position are set. In this way, the power recovery loss described below can be prevented as compared with the circular communication hole described in FIG. 11A and the like.

  As can be seen from FIG. 11A and the like, when a conventional circular communication hole is employed, a space is inevitably generated between the vane and the communication hole. A very small amount of refrigerant stays in this space without being sent to the second cylinder, but receives a compression action according to the rotation of the piston, generates a torque that brakes the rotation of the piston, and causes a recovery loss of expansion energy. On the other hand, by adopting the communication hole 104b of the present embodiment, it is possible to almost eliminate the space where the refrigerant is left, so that more energy can be recovered compared to the conventional circular communication hole. Become.

Next, the second cylinder 106 side will be described. As shown in FIG. 3B, on the second cylinder 106 side, the communication hole 104 b includes an opening edge h ₁ i ₁ coinciding with the inner peripheral surface of the second cylinder 106 and an opening edge i ₁ along the movable range of the second vane 112. Its shape and position can be set to include j ₁ . The other opening edges h ₁ k ₁ and j ₁ k ₁ can be appropriately determined so as to ensure a sufficient opening area. For example, in the present embodiment, the opening edge h ₁ i ₁ j ₁ k ₁ of the communication hole 104 b forms a part of a sector shape with the rotation axis O as the center. By adjusting the opening shape and position of the communication hole 104b in this way, the following effects can be expected.

  As shown in FIGS. 10A and 10B, in the case of the conventional circular communication hole 204a, a space is inevitably generated between the communication hole 204a and the vane even if the circular communication hole 204a is brought close to the vane. This problem has already been described. If there is such a space on the second cylinder 206 side, no matter how the communication timing between the working chamber 215b of the first cylinder 205 and the working chamber 216a of the second cylinder 206 is optimized, Until just before the communication timing arrives, the refrigerant is not supplied from the communication hole 104b, and the volume is increased from a state where there is almost no refrigerant. Such a phenomenon generates a brake torque in a direction opposite to the rotational direction of the piston. As a result, if the communication hole 104b communicates with the working chamber on the second cylinder 206 side, which has become very low in pressure, the expansion energy of the refrigerant is consumed by free expansion, and power cannot be recovered. Thus, the space between the communication hole 104b and the vane is a cause of reducing the performance of the expander.

However, according to the communication hole 104b in the present embodiment, the volume of the space between the opening edge h ₁ i ₁ j ₁ k ₁ and the second vane 112 is substantially equal to zero. Therefore, by appropriately adjusting the phase difference between the first piston 109 and the second piston 110, and the positions of the first vane 111 and the second vane 112, generation of torque for applying the brake is prevented, or It can be sufficiently reduced.

Note that a communication hole 104b ′ in which the opening shape and position on the second cylinder 106 side are determined by the same rules as those on the first cylinder 105 side can also be employed. That is, as indicated by a broken line in FIG. 3C, the opening edge h ₂ i ₂ on the second cylinder 106 side is inscribed in the second cylinder 106 at a point h ₂ (second angular position) in the circumferential direction. The shape and position of the communication hole 104b ′ (the shape and position of the opening edge h ₂ i ₂ j ₂ k ₂ ) can be set so as to form a part of a virtual circle having the same diameter as the outer diameter d ₂ . In this case, as can be easily understood from FIG. 2A, the point H ₁ (first angular position) shown in FIG. 3A and the point h ₂ (second angular position) shown in FIG. Matches around axis O. That is, the communication hole 104b ′ extends straight from the first cylinder 105 toward the second cylinder 106 along the rotation axis O of the shaft 103 so that the cross-sectional shape is constant in the direction along the rotation axis O. . With such a shape, the processing of the intermediate plate 104 is easy, and the communication hole 104b connects the first cylinder 105 and the second cylinder 106 with the shortest distance, so that the pressure loss can be minimized.

Also, a communication hole having different opening positions on the first cylinder 105 side and the second cylinder side 106 can be employed. That is, it is possible to form a communication hole for communicating the first discharge side working chamber 115b of the first cylinder 105 and the second suction side working chamber 116a of the second cylinder 106 by drilling the middle plate 104 obliquely. It is. When doing so, the point H ₁ (first angle position) on the first cylinder 105 side and the point h ₁ (second angle position) on the second cylinder 106 side do not coincide with each other, and they are separated by a predetermined angle. It becomes.

In addition, the cross-sectional shape (transverse cross-sectional shape) of the communication hole 104b in the direction perpendicular to the rotation axis O may or may not be constant in the direction along the rotation axis O. Specifically, as shown in FIG. 3D, the through hole TH is formed by penetrating the intermediate plate 104 in the thickness direction and forming a through hole TH having a circular cross-sectional shape, and then sitting on both ends of the through hole TH. _A communication hole 134b having ₁ I ₁ J ₁ K ₁ (first cylinder 105 side) and an opening edge h ₁ i ₁ j ₁ k ₁ (second cylinder 106 side) is formed. In this way, the middle plate 104 can be easily processed.

When the shaft 103 rotates counterclockwise in the communication hole 104b having the above-described shape, the state of communication between the first discharge side working chamber 115b and the communication hole 104b is as shown in FIGS. 4A to 4D. . The moment the first discharge-side working chamber 115b and the communication hole 104b is communicated, is when the contact point between the first piston 109 and the first cylinder 105 matches the point H _1. FIG. 4A shows a moment when the first discharge side working chamber 115b and the communication hole 104b communicate with each other. It can be seen that the opening edge H ₁ I ₁ of the communication hole 104 b coincides with the outer peripheral edge of the first piston 109. FIG. 4B shows a state in which the shaft 103 is rotated by 20 ° after the first discharge side working chamber 115b and the communication hole 104b communicate with each other. FIG. 4C shows a state in which the shaft 103 is rotated by 40 ° after the first discharge side working chamber 115b and the communication hole 104b communicate with each other. FIG. 4D shows a state in which the shaft 103 is rotated by 60 ° after the first discharge side working chamber 115b and the communication hole 104b communicate with each other. In each figure, the communication portion between the first discharge side working chamber 115b and the communication hole 104b is indicated by hatching. It can be understood that the region along the opening edge H ₁ I ₁ immediately appears as a communication portion immediately after the start of communication.

  FIG. 5 shows the relationship between the rotation angle of the shaft 103 and the ratio of the communication area between the first discharge side working chamber 115b and the communication hole 104b. The time (communication start time) at which communication between the first discharge-side working chamber 115b of the first cylinder 105 and the communication hole 104b starts is defined as zero rotation angle of the shaft 103. In the present invention, with the shaft 103 rotated 20 ° after the first discharge side working chamber 115b and the communication hole 104b communicated, the communication area reached 14% of the opening area of the communication hole 104b and rotated 40 °. The state has reached about 40%. That is, the communication area is rapidly increasing in the initial stage from the start of communication. When the shaft 103 rotates about 80 ° from the start of communication, the first discharge side working chamber 115b and the communication hole 104b are completely in communication. Therefore, by adopting the communication hole 104b of this embodiment, it is possible to reduce the pressure loss by shortening the time for which the refrigerant passes through the minute gap as much as possible. In addition, in the case of the conventional circular communication hole 204a, it turns out that the increase speed of a communication area is remarkably small compared with this invention.

(Second Embodiment)
FIG. 6 shows a communication hole 104 c in which the opening edge H ₂ I ₂ is set along the first cylinder 105 from the shaft 103. Of the opening edges of the communication hole 104 c, the opening edge H ₂ I ₂ located farthest from the shaft 103 forms a part of a circle having the same diameter as the inner diameter D ₁ of the first cylinder 105, and the shaft 103 rotates. In the direction parallel to the axis O, the arc-shaped opening edge H ₂ I ₂ coincides with the inner peripheral surface of the first cylinder 105. This also applies to the second cylinder 106 side. The positional relationship between the first cylinder 105 and the second cylinder 106 is also the same as in the first embodiment.

When the shaft 103 rotates counterclockwise, the state of communication between the first discharge side working chamber 115b and the communication hole 104c is as shown in FIGS. 7A to 7D. The moment the first discharge-side working chamber 115b and the communication hole 104c is communicated, it is when the contact point between the first piston 109 and the first cylinder 105 matches the point I _2. FIG. 7A shows a moment when the first discharge side working chamber 115b and the communication hole 104c communicate with each other. FIG. 7B shows a state in which the shaft 103 is rotated by 20 ° after the first discharge side working chamber 115b and the communication hole 104c communicate with each other. FIG. 7C shows a state in which the shaft 103 is rotated by 40 ° after the first discharge side working chamber 115b and the communication hole 104c communicate with each other. FIG. 7D shows a state in which the shaft 103 is rotated by 60 ° after the first discharge side working chamber 115b and the communication hole 104c communicate with each other. In each figure, the communication portion is indicated by hatching.

  FIG. 8 shows the relationship between the rotation angle of the shaft 103 and the ratio of the communication area between the first discharge side working chamber 115b and the communication hole 104c. The increase speed of the communication area when the communication hole 104c of this embodiment is adopted is sufficiently large as compared with the conventional circular communication hole 204a.

(Third embodiment)
FIG. 9 shows the communication hole 104 d that is partially hidden behind the first cylinder 105. The communication hole 104 d as shown in FIG. 9 can be formed by moving a drill for drilling the intermediate plate 104 along the circumferential direction of the first cylinder 105. Although the communication hole 104 d is partially blocked by the first cylinder 105, the substantial opening edge is an arc H ₃ I ₃ that coincides with the inner peripheral surface 105 p of the first cylinder 105.

Assuming that the direction along the circumferential direction of the first cylinder 105 is the longitudinal direction, the communication hole 104d forms an arc having the same diameter at the opening edges H ₃ K ₃ and I ₃ J ₃ located at both ends in the longitudinal direction. An opening edge H ₃ I ₃ along the longitudinal direction coincides with the inner peripheral surface 105 p of the first cylinder 105. Furthermore, the opening edge J ₃ K _3, which is another opening edge along the longitudinal direction and is located on the opposite side of the opening edge H ₃ I ₃ that coincides with the inner peripheral surface 105 p of the first cylinder 105, It forms a part of a virtual circle having the same diameter as the inner diameter of one cylinder 105. Even in the communication hole 104d having such a shape, the increase speed of the communication area is sufficiently larger than that of the conventional circular communication hole 204a. The same applies to the second cylinder 106 side.

  As described above, the communication holes 104b, 104b ′, 104c, 104d, and 134 described in the present embodiment are used to communicate between the discharge side working chamber 115a of the first cylinder 105 and the suction side working chamber 116a of the second cylinder 106. Can be performed promptly. That is, since the state where the minute gap in the communicating portion leaks is short, the pressure loss can be reduced, and the efficiency of the expander can be improved. Further, the present invention is particularly effective when carbon dioxide, which generates a large pressure difference reaching 50 atm between the discharge side working chamber 115a of the first cylinder 105 and the suction side working chamber 116a of the second cylinder 106, is used as the refrigerant. It is valid.

  In the present embodiment, the opening shapes of the communication holes 104b, 104b ′, 104c, and 104d are mentioned. However, the cross-sectional shapes of the communication holes 104b, 104b ′, 104c, and 104d are not particularly limited, and the opening shape is left as it is in the middle plate. There is no need to reflect in the inside of 104. For example, as described in FIG. 3D, the opening shape is set as in this embodiment, and the communication hole in which the inside of the intermediate plate is cylindrical can obtain the same effect as in this embodiment.

  In the present embodiment, the case of a two-stage rotary expander has been described as an example, but the same effect can be obtained even in a multistage type having three or more stages.

  The two-stage rotary expander 100 of the present invention is useful as a power recovery means for recovering the expansion energy of the refrigerant in the refrigeration cycle, and also useful as an energy recovery means from a compressive fluid other than the refrigerant.

1 is a longitudinal sectional view of a two-stage rotary expander according to an embodiment of the present invention. Cross-sectional view of the two-stage rotary expander of FIG. Another cross-sectional view of the two-stage rotary expander of FIG. Partial enlarged view of FIG. 2A Partial enlarged view of FIG. 2B The top view which shows the modification of a communicating hole Sectional drawing which shows the other modification of a communicating hole Operation explanatory diagram showing the communication state between the working chamber and the communication hole Figure following Figure 4A Figure following Figure 4B Figure following Figure 4C A graph showing the relationship between the rotation angle of the shaft and the ratio of the communication area of the communication hole The top view which shows the other form of a communicating hole Operation | movement explanatory drawing which shows the communication state of the communicating hole and working chamber which are shown in FIG. Figure following Figure 7A Figure following Figure 7B Figure following Figure 7C The graph which shows the relationship between the rotation angle of a shaft, and the ratio of the communication area of the communication hole shown in FIG. The top view which shows the other form of a communicating hole Cross-sectional view of a conventional two-stage rotary expander Another cross-sectional view of a conventional two-stage rotary expander Operation explanatory diagram showing the communication state between the circular communication hole and the working chamber Figure following Figure 11A Figure following Figure 11B Figure following Figure 11C Graph showing the relationship between the rotation angle of the shaft and the ratio of the communication area of the circular communication hole

Explanation of symbols

100 Two-stage rotary expander 101 Generator 102 Sealed container 103 Shaft 104 Middle plate 105 First cylinder 106 Second cylinder 109 First piston 110 Second piston 104b, 104b ', 104c, 104d, 134 Communication hole 115b First discharge Side working chamber 116a second suction side working chamber 120 expansion mechanism section

Claims (6)

A first cylinder;
A shaft penetrating the inside and outside of the first cylinder;
A first piston attached to the shaft and rotating eccentrically in the first cylinder;
A second cylinder disposed concentrically with the first cylinder so as to share the shaft;
A second piston attached to the shaft and rotating eccentrically in the second cylinder;
A first partition member that is movably mounted in a first groove formed in the first cylinder and partitions a space between the first cylinder and the first piston into a first suction side space and a first discharge side space. When,
A second partition member that is movably mounted in a second groove formed in the second cylinder and partitions a space between the second cylinder and the second piston into a second suction side space and a second discharge side space. When,
The first discharge side space and the second suction side space communicate with each other to form a working chamber, and include a middle plate that separates the first cylinder from the second cylinder,
When the outer diameter of the first piston is defined as d ₁ and the inner diameter of the first cylinder is defined as D ₁ ,
In the communication hole, a part of an opening edge on the first cylinder side forms a part of a virtual circle having a diameter d ₁ or more and less than D ₁ inscribed in the first cylinder at a first angular position. A multi-stage rotary fluid machine whose shape and position are set so as to extend from an angular position in a direction opposite to the rotation direction of the first piston. A first cylinder;
A shaft penetrating the inside and outside of the first cylinder;
A first piston attached to the shaft and rotating eccentrically in the first cylinder;
A second cylinder disposed concentrically with the first cylinder so as to share the shaft;
A second piston attached to the shaft and rotating eccentrically in the second cylinder;
A first partition member that is movably mounted in a first groove formed in the first cylinder and partitions a space between the first cylinder and the first piston into a first suction side space and a first discharge side space. When,
A second partition member that is movably mounted in a second groove formed in the second cylinder and partitions a space between the second cylinder and the second piston into a second suction side space and a second discharge side space. When,
The first discharge side space and the second suction side space communicate with each other to form a working chamber, and include an intermediate plate that separates the first cylinder and the second cylinder;
In the direction parallel to the rotation axis of the shaft, the communication hole is set in shape and position so that a part of the opening edge on the first cylinder side is along the inner peripheral surface of the first cylinder. Multistage rotary fluid machine. 3. The multistage rotary fluid machine according to claim 1, wherein the first cylinder and the second cylinder are concentrically arranged with their inner diameters D ₁ and D ₂ set equal. The first partition member and the second partition member are arranged at a predetermined angle around the rotation axis of the shaft,
The communication hole is formed in the intermediate plate so as to extend from the first cylinder toward the second cylinder in an angular region sandwiched between the first partition member and the second partition member. The multistage rotary fluid machine according to any one of claims 1 to 3.   4. The shape and position of the communication hole are set so that an opening edge on the first cylinder side is along a movable range of the first partition member. 5. A multi-stage rotary fluid machine according to claim 1.   The shape and position of the communication hole are set such that an opening edge on the second cylinder side is along an inner peripheral surface of the second cylinder and a movable range of the second partition member. The multistage rotary fluid machine according to any one of claims 3 to 3.

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