JP2006336597A - Expander - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an expander capable of reducing amount of oil discharge by a simple and highly reliable configuration and achieving high efficiency and high reliability. <P>SOLUTION: Annular channels 401, 402 are provided in bearings 105, 106 sliding with upper and lower end faces of a piston 107, and a sealing material 403 is provided in them to reduce amount of oil flowing into operation chambers 110a, 110b from the vicinity of an eccentric part 103a. In this expander used in refrigerating cycle, since working fluid is expanded from supercritical phase or liquid phase into gas-liquid two phases, oil is diluted by working fluid having liquid phase, its viscosity is reduced, and wear of the sealing material 403 may occur. For this reason, a rotation prevention mechanism such as an engaging channel 107a in which a tip of a vane 108 is fitted is provided on an outer peripheral face of the piston 107 to reduce sliding speed among the sealing material 403 and upper and lower end faces of the piston 107 and prevent wear of the sealing material 403. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an expander that generates power by recovering expansion energy of a high-pressure compressive fluid, and more particularly to an expander that replaces a throttle mechanism in a refrigeration cycle and recovers expansion power of a refrigerant. .

  As an expander used for the purpose of recovering expansion energy when the refrigerant of the refrigeration cycle apparatus expands, a rotary type expander is known (for example, see Patent Document 1 and Non-Patent Document 1).

  The configuration of a rotary expander as disclosed in Patent Document 1 will be described below. However, in order to simplify the description, a single piston type is used.

  9 is a longitudinal sectional view showing a configuration of a conventional rotary expander 100, and FIG. 10 is a transverse sectional view taken along line D1-D1 of the expander 100 of FIG. The generator 101 includes a stator 101a fixed to the hermetic container 102 and a rotor 101b fixed to the shaft 103. The rotor 101b rotates to generate an electromotive force between the stator 101a and the stator 101a to obtain electric power. . The shaft 103 passes through the cylinder 104 and is rotatably supported by bearings 105 and 106. The shaft 103 is provided with an eccentric portion 103a, and a piston 107 disposed inside the cylinder 104 is fitted into the eccentric portion 103a. In addition, an axial flow path 103b is provided in the longitudinal direction of the shaft 103, and a radial flow path 103d that connects the axial flow path 103b and the opening 103c is provided in the eccentric portion 103a.

  As shown in FIG. 10, an engagement groove 107 a is formed on the outer peripheral surface of the piston 107, and a vane groove 104 a is formed in the cylinder 104. The vane 108 reciprocally held by the vane groove 104a engages with the engagement groove 107a at the tip, and the piston 108 is always driven by the force of the spring 109 or the force difference between the tip side and the back side of the vane 108. It is in close contact with the 107 side. A crescent-shaped space formed by the cylinder 104 and the piston 107 is partitioned by the vane 108 into two working chambers 110a and 110b. The suction hole 107b provided in the piston 107 communicates with the working chamber 110a, and the discharge hole 104b provided in the cylinder 104 communicates with the working chamber 110b.

  The high-pressure working fluid flows into the sealed container 102 from the suction pipe 111, and then reaches the opening 103c through the axial flow path 103b and the radial flow path 103d of the shaft 103. The opening 103c rotates with the rotational motion of the shaft 103, but the piston 107 performs an eccentric rotational motion without so-called rotational motion, so-called rocking motion. For this reason, the suction hole 107 b provided in the piston 107 and the opening 103 c provided in the eccentric part 103 a repeat communication and non-communication with the rotational movement of the shaft 103. The working fluid is sucked into the working chamber 110a while the opening 103c and the suction hole 107b communicate with each other. Thereafter, when the opening 103c and the suction hole 107b are not in communication, the suction stroke ends. The working fluid expands while reducing the pressure, and rotates the shaft 103 in the direction in which the volume of the working chamber 110a expands to drive the generator 101. As the shaft 103 rotates, the working chamber 110a shifts to the working chamber 110b, and the expansion stroke ends when the working chamber 110a communicates with the discharge hole 104b. Then, the low-pressure working fluid is discharged from the discharge hole 104b to the discharge pipe 112.

  Oil for lubricating the expander is stored in an oil sump 113 at the bottom of the hermetic container 102, and the helical shape provided on the sliding surface of the bearings 105, 106 with the shaft 103 as the shaft 103 rotates. It is pumped up by the dynamic pressure generated by the oil grooves 105a and 106a, and lubricates between the sliding surface between the shaft 103 and the bearings 105 and 106, and between the eccentric portion 103a and the inner surface of the piston 107. Further, the oil in the vicinity of the eccentric portion 103a lubricates the sliding surfaces of the upper and lower surfaces of the piston 107 when flowing into the working chambers 110a and 110b where the pressure becomes lower. The oil that has lubricated the upper and lower end surfaces of the piston 107 flows into the working chambers 110a and 110b, is mixed with the working fluid, and is discharged from the discharge pipe 112 together.

  Next, the configuration of a conventional rotary expander as shown in Non-Patent Document 1 will be described below. The rotary expander of Non-Patent Document 1 has the same basic configuration as the compressor shown in Patent Document 2, although the refrigerant flow and the shaft rotation direction are opposite.

  11 is a longitudinal sectional view showing a configuration of a conventional rotary expander 200, FIG. 12 (a) is a transverse sectional view taken along line D2-D2 of the expander 200 of FIG. 11, and FIG. 12 (b) is FIG. It is a cross-sectional view in the line D3-D3 of the expander 200. The generator 201 includes a stator 201 a fixed to the hermetic container 202 and a rotor 201 b fixed to the shaft 203. The shaft 203 passes through a first cylinder 205 and a second cylinder 206 that are partitioned independently by an intermediate plate 204, and is rotatably supported by bearings 207 and 208. The shaft 203 is provided with a first eccentric portion 203 a and a second eccentric portion 203 b that have the same eccentric direction with respect to the axis of the shaft 203, and the first eccentric portion 203 a is arranged inside the first cylinder 205. The second piston 210 arranged inside the second cylinder 206 is fitted into the second eccentric portion 203b.

  The height and diameter of the first cylinder 205 and the first piston 209, and the second cylinder 206 and the second piston 210 are crescent-shaped spaces formed by the first cylinder 205 and the first piston 209. Is set to be smaller than the crescent-shaped space formed by the second cylinder 206 and the second piston 210. Vane grooves 205a and 206a are formed in the first cylinder 205 and the second cylinder 206, respectively. The first vane 211 and the second vane 212, which are reciprocally held by the vane grooves 205a and 206a, respectively, are caused by the force caused by the springs 213 and 214 and the pressure difference between the front end side and the rear side of each vane 211 and 212. Are in close contact with the pistons 209 and 210, respectively. The crescent-shaped space formed by the first cylinder 205 and the first piston 209 is divided into two working chambers 215a and 215b by the first vane 211, and the second cylinder 206 and the second piston 210. The crescent-shaped space formed by is divided into two working chambers 216 a and 216 b by the second vane 212. The suction hole 205b provided in the first cylinder 205 communicates with the working chamber 215a, and the working chamber 215b and the working chamber 216a pass between the first vane 211 and the second vane 212. The middle plate 204 communicates with a communication hole 204a provided in an oblique direction to form one space. The discharge hole 206b provided in the second cylinder 206 communicates with the working chamber 216b.

  The high-pressure working fluid flows into the sealed container 202 from the suction pipe 217 and is then sucked into the working chamber 215a in the first cylinder 205 through the suction hole 205b. With the rotational movement of the shaft 203, the volume of the working chamber 215a increases, and eventually, the working chamber 215b communicates with the communication hole 204a on the first cylinder 205 side, and the suction stroke ends. The working chamber 215b communicates with the working chamber 216a of the second cylinder 206 through the communication hole 204a to form one working chamber, and the high-pressure working fluid has a direction in which the volume of the whole working chamber communicated increases. That is, the volume of the working chamber 215b decreases, the shaft 203 is rotated in the direction in which the volume of the working chamber 216a increases, and the generator 201 is driven. As the shaft 203 rotates, the working chamber 215b disappears, the working chamber 216a moves to the working chamber 216b communicating with the discharge hole 206b, and the expansion stroke ends. Then, the low-pressure working fluid is discharged from the discharge hole 206b to the discharge pipe 218.

  Oil for lubricating the expander is stored in an oil sump 219 at the bottom of the hermetic container 202, and the helical shape provided on the sliding surface of the bearings 207 and 208 with the shaft 203 as the shaft 203 rotates. Pumped up by the dynamic pressure generated by the oil grooves 207a and 208a, the sliding surfaces between the shaft 203 and the bearings 207 and 208, the first eccentric portion 203a and the inner surface of the first piston 209, the second Lubrication is performed between the eccentric portion 203b and the inner surface of the second piston 210. Further, when the oil in the vicinity of the eccentric parts 203a and 203b sequentially flows into the working chambers 215a, 215b, 216a, and 216b where pressure is lowered, the sliding surfaces of the upper and lower end surfaces of the pistons 209 and 210 are lubricated. . The oils that have lubricated the upper and lower end surfaces of the pistons 209 and 210 sequentially flow into the working chambers 215a, 215b, 216a, and 216b, are mixed with the working fluid, and are discharged from the discharge pipe 218 together.

  In the expander of Patent Document 1 and the expander of Non-Patent Document 1 described above, when oil is discharged together with the working fluid from the discharge pipe, the oil in the oil reservoirs 113 and 219 below the sealed containers 102 and 202 is depleted, The sliding part cannot be lubricated, and the reliability of the expander decreases. Moreover, the oil which seals a clearance gap for the same reason is insufficient, and the performance of the expander also deteriorates. Therefore, it is necessary to reduce the amount of oil flowing into the working chamber from the upper and lower end surfaces of the pistons 107, 209, and 210.

In a conventional compressor having a configuration similar to that of a conventional expander, Patent Documents 3 and 4 disclose a structure that reduces the amount of oil flowing into the working chamber from the upper and lower end surfaces of the piston. FIG. 13 shows a conventional compressor of Patent Document 3. In this configuration, the sealing materials 304 and 305 are provided on the sliding surfaces of the bearing members 302 and 303 facing the upper and lower end surfaces of the piston 301. FIG. 14 shows a conventional compressor of Patent Document 4. In this configuration, sealing materials 307 and 308 are provided on the upper and lower end surfaces of the swing piston 306.
JP 08-338356 A JP 2003-343467 A Japanese Patent Laid-Open No. 61-215482 Japanese Patent Laid-Open No. 09-100791 "Research and Development of Energy-Effective Utilization Fundamental Technology Development of Two-phase Flow Expander / Compressor for CO2 Air Conditioner" March 2004 (Germany) New Energy and Industrial Development Organization

  However, in the expander used for the refrigeration cycle, the working fluid expands from the liquid phase or supercritical phase to the gas-liquid two phase, so that the oil is diluted to the liquid phase working fluid, and the oil viscosity is greatly reduced. When a sealing material is used in the configuration of the compressor of Patent Document 3 shown in FIG. 13, the sliding speed between the sealing material and the upper and lower end surfaces of the piston becomes very large due to the rotation of the piston. In the case of (3), the wear of the sealing material became remarkable, and the reliability was lowered.

  Moreover, when using a sealing material with the structure of the compressor of patent document 4 shown in FIG. 14, it is necessary to provide the groove | channel which fits a sealing material in the upper-lower-end surface of a piston, but since a piston end surface is narrow, it is processed. It is difficult to raise the processing cost and secure the processing accuracy. In addition, the provision of the groove reduces the strength in the vicinity of the inner and outer peripheral edges of the upper and lower end surfaces of the piston and causes the piston edge to bend the mating sliding surface by being deformed by the pressure of the working fluid acting on the piston. Cause abnormal wear.

  In the conventional compressor shown in FIGS. 13 and 14, the working fluid exiting the working chamber is once discharged into the inner space of the sealed container, and after separating the oil from the working fluid by centrifugal force or gravity, Since the working fluid in which the oil to be mixed is sufficiently reduced is discharged from the discharge pipe to the outside of the compressor, the oil in the oil reservoir is always held, but Patent Document 1 and Non-Patent Documents shown in FIGS. In the conventional expander described in No. 1, the working fluid exiting the working chamber is discharged from the discharge pipe without separating the oil by centrifugal force or gravity. Therefore, in the conventional expander, compared with the conventional compressor, the oil in the oil reservoir in the lower part of the closed container is easily depleted, and the reliability is deteriorated due to insufficient lubrication and the performance is deteriorated due to insufficient seal. In addition, since the oil discharged from the expander adheres to the inside of the heat transfer tube of the heat exchanger of the refrigeration cycle and lowers the heat transfer performance, the COP of the refrigeration cycle is lowered.

  The present invention has been made in view of the above circumstances, and in an expander used in a refrigeration cycle, an oil discharge amount is reduced by a simple and reliable configuration, and a highly efficient and highly reliable expander, and It aims to provide a highly efficient refrigeration cycle.

  In order to solve the above-described problems, an expander according to the present invention includes at least a shaft having an eccentric portion, a piston connected to the eccentric portion of the shaft and performing an eccentric rotational movement, and an inner surface having a cylindrical shape. A cylinder arranged so that a part of its inner surface is in contact with the piston, a closing member that closes both end faces of the cylinder, and a crescent-shaped space constituted by the cylinder, the piston, and the closing member A partition member that is divided into a discharge side space, a mechanism that prevents the piston from rotating, a groove provided on a sliding surface of the closing member with the piston, and a seal material provided in the groove Features.

  The expander of the present invention is characterized in that a concave portion is provided on the outer peripheral surface of the piston, and the tip of the partition member is fitted into the concave portion to prevent the piston from rotating.

  In the expander of the present invention, the piston and the partition member are integrally formed.

  In the expander of the present invention, the radial width of the piston is larger than a value obtained by adding the radial width of the groove to twice the width of the eccentric amount of the eccentric portion of the shaft.

  The expander of the present invention is characterized in that the sealing material is pressed against the sliding surface of the piston by a spring provided in the groove of the closing member.

  The expander of the present invention is characterized in that a taper is provided on the outer peripheral side wall surface of the groove of the closing member.

  The expander of the present invention is characterized by using carbon dioxide as a working fluid.

  According to the expander of the present invention, it is possible to greatly reduce the amount of oil flowing into the working chamber with a simple configuration. Therefore, the oil discharge amount of the expander is reduced, and high efficiency and high reliability are achieved. An expander and a highly efficient refrigeration cycle can be realized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
1 is a longitudinal sectional view showing a configuration of an expander 400 according to Embodiment 1 of the present invention, FIG. 2 is a transverse sectional view taken along line D1-D1 of the expander 400 of FIG. 1, and FIG. It is a perspective view of the sealing material of the expander 400. FIG. The configuration of the expander 400 according to the first embodiment is the same as that of the conventional expander 100 described with reference to FIGS. 9 and 10 except that a sealing material is installed. Also, the same numbers are used for the same functional parts, and the description of the same configuration and operation as in the conventional example is omitted.

  In the expander 400 of the first embodiment, the annular grooves 401 and 402 are provided on the sliding surfaces of the bearings 105 and 106 with the upper and lower end surfaces of the piston 107, and the sealing material 403 is installed therein. The sealing material 403 is preferably made of a resin such as polyimide (Vespel PS-1), polyphenylene sulfide (PPS), polyether ether ketone (PEEK). Further, an annular sealing material 403 as shown in FIG. 3A may be used, but a sealing material 403 provided with a cut 403a at one place as shown in FIG. 3B is more preferable. The range of the radial width w of the piston 107 satisfies the relationship of w> 2e + s between the eccentric amount e that is the distance from the axis of the shaft 103 to the axis of the eccentric portion 103a and the width s of the sealing material 403. Like that.

  By adopting such a configuration, the sealing material 403 receives pressure on the inner surface side thereof and adheres closely to the outer peripheral surfaces of the annular grooves 401 and 402. Further, by closely contacting the outer peripheral surfaces of the annular grooves 401 and 402, high pressure oil that has entered between the bottom surfaces of the annular grooves 401 and 402 and the sealing material 403 is prevented from leaking into the working chambers 110a and 110b having a low pressure. To do. These high-pressure oils press the sealing material 403 against the upper and lower end surfaces of the piston 107. Therefore, the amount of oil that passes between the sealing material 403 and the upper and lower surfaces of the piston 107 and flows into the working chambers 110a and 110b from the eccentric portion 103a can be greatly reduced. At this time, by adjusting the width s of the sealing material 403, the amount of oil flowing in is controlled, and only the minimum oil necessary for lubrication is allowed to flow to ensure reliability. Therefore, the amount of oil mixed with the working fluid and flowing out from the discharge pipe 112, that is, the amount of oil discharged, is greatly reduced, resulting in a highly efficient and reliable expander, and the performance of the refrigeration cycle due to oil is reduced. Can be prevented.

  In addition, by providing the cut 403a, even when there is a difference in processing diameter between the diameter of the sealing material 403 and the diameter of the outer circumferential surface of the annular grooves 401, 402, the sealing material 403 is securely attached to the outer circumferential surface of the annular grooves 401, 402. It can be adhered.

  In the first embodiment, the rotation of the piston 107 is prevented by fitting the vane 108 into the engagement groove 107 a of the piston 107, so that the seal material 403 slides between the upper and lower end surfaces of the piston 107. The speed can be suppressed, wear of the sealing material 403 can be prevented, and reliability can be improved.

  Further, when the radial width w of the piston 107, the eccentricity e, and the width s of the sealing material 403 satisfy the relationship of w> 2e + s, the point Q on the inner peripheral side of the piston 107 indicated by a broken line in FIG. The seal material 403 can be installed in a configuration in which the locus and the locus of the point P on the outer peripheral side of the piston 107 do not pass over the seal material 403. In other words, the sealing material 403 is between the point Q on the inner peripheral side and the point P on the outer peripheral side of the piston 107, that is, within the range on the upper and lower end surfaces of the piston 107, regardless of the rotation angle of the shaft 103. Therefore, the seal material 403 ensures the seal between the bearings 105, 106 and the upper and lower end surfaces of the piston 107, and the inner or outer edge of the upper and lower end surfaces of the piston 107 rubs against the seal material 403. It is possible to prevent the sealing material 403 from being damaged.

  Note that the sealing material 403 is not necessarily annular, and the grooves 401 and 402 formed in the bearings 105 and 106 have the same shape as the sealing material 403, and the sealing material 403 is in contact with the upper and lower end surfaces of the piston 107. Needless to say, similar effects can be obtained.

  The expander according to the first embodiment has a configuration in which the piston 107 does not rotate by fitting the tip of the vane 108 into the engagement groove 107a of the piston 107. If the 107 does not have a structure for rotating, it is necessary to prevent the rotation of the piston 107 by adding an engagement groove 107 a to the piston 107.

  In the case where the refrigeration cycle is a supercritical cycle using carbon dioxide as a working fluid, the pressure difference between the high pressure side and the low pressure side of the refrigeration cycle becomes very large. Needless to say, it becomes more prominent.

(Embodiment 2)
The second embodiment has the same configuration as that of the first embodiment except that the spring 404 is installed in the annular grooves 401 and 402 together with the sealing material 403.

  FIG. 4 is a perspective view of expander bearing 106, seal material 403, and spring 404 according to Embodiment 2 of the present invention. In the second embodiment, the spring 404 is first inserted into the annular groove 402 of the bearing 106 and then the sealing material 403 is fitted. The spring 404 is a thin leaf spring having ring-shaped and wavy irregularities. Similarly, after the spring 404 is inserted into the annular groove 401 of the bearing 105, the sealing material 403 is fitted.

  Needless to say, the spring 404 has the effect of pressing the sealing material 403 against the upper and lower end surfaces of the piston 107 by the spring 404, and further, the spring 404 provides a space between the bottom surface of the annular grooves 401 and 402 and the sealing material 403. Since the gap is surely generated, the high pressure oil flows between the sealing material 403 and the bottom surfaces of the annular grooves 401 and 402, thereby pressing the sealing material 403 against the upper and lower end surfaces of the piston 107 as described in the first embodiment. The effect can be made more reliable. For this reason, the amount of oil that passes between the sealing material 403 and the upper and lower surfaces of the piston 107 and flows into the working chambers 110a and 110b from the eccentric part 103a can be further reduced.

  The spring 404 is not necessarily a thin plate spring. It goes without saying that the same effect can be obtained if a gap can be provided between the bottom surfaces of the annular grooves 401 and 402 and the sealing material 403.

(Embodiment 3)
The third embodiment of the present invention has the same configuration as that of the first embodiment except that the outer peripheral surface of the sealing material 413 and the outer peripheral surfaces of the annular grooves 411 and 412 are tapered surfaces.

  FIG. 5 is an enlarged vertical sectional view of an expansion mechanism portion of the expander according to Embodiment 3 of the present invention. In the third embodiment, the sealing material 413 is annular as in the first embodiment, but the outer peripheral surface 413a of the sealing material 413 is tapered such that the diameter of the outer peripheral surface 413a increases toward the piston 107 side. It is a surface. Similarly, the outer peripheral surfaces 411a and 412a of the annular grooves 411 and 412 provided in the bearings 105 and 106 are also tapered surfaces having the same inclination as the outer peripheral surface 413a of the sealing material 413.

  By adopting such a configuration, the sealing material 413 receives pressure on the inner surface side and closely contacts the outer peripheral surfaces 411a and 412a of the annular grooves 411 and 412. At that time, the outer peripheral surface 413a of the sealing material 413 is The reaction force received from the outer peripheral surfaces 411a and 412a of the annular grooves 411 and 412 is perpendicular to the outer peripheral surface 413a of the seal material 413 and has a component force toward the piston 107. The piston 107 is pressed against the upper and lower end surfaces. For this reason, a gap is surely generated between the bottom surfaces of the annular grooves 411 and 412 and the sealing material 413, so that high-pressure oil flows between the sealing material 413 and the bottom surfaces of the annular grooves 411 and 412, thereby sealing the material 413. The effect described in the first embodiment of pressing the piston 107 against the upper and lower end surfaces of the piston 107 can be made more reliable. For this reason, the amount of oil that passes between the sealing material 413 and the upper and lower surfaces of the piston 107 and flows into the working chambers 110a and 110b from the eccentric portion 103a can be further reduced.

(Embodiment 4)
The fourth embodiment of the present invention has the same configuration as that of the first embodiment except for the shape of the sealing material 423.

  FIG. 6 is an enlarged longitudinal sectional view of an expansion mechanism portion of the expander according to Embodiment 4 of the present invention. In the fourth embodiment, the sealing material 423 is annular as in the first embodiment, but the inner circumferential side cross section of the sealing material 423 is formed in a concave shape.

  By adopting such a configuration, a high pressure acts on the concave portion on the inner peripheral side of the sealing material 423 and a low pressure acts on the outer peripheral side, so that the sealing material 423 is pushed up and down to form an annular shape with the upper and lower end surfaces of the piston 107. The grooves 421 and 422 are in close contact with both bottom surfaces. Therefore, the amount of oil that passes between the sealing material 423 and the upper and lower surfaces of the piston 107 and flows into the working chambers 110a and 110b from the eccentric portion 103a can be greatly reduced.

(Embodiment 5)
7 is a longitudinal sectional view showing the configuration of the expander 430 according to the fifth embodiment of the present invention. FIG. 8A is a transverse sectional view taken along the line D2-D2 of the expander in FIG. ) Is a cross-sectional view taken along line D3-D3 of the expander of FIG. The configuration of the expander 430 of the fifth embodiment is the conventional configuration described with reference to FIGS. 11 and 12 except that the pistons 209 and 210 do not rotate and the seal material 435 is installed. The configuration is the same as that of the expander 200. Also, the same numbers are used for the same functional parts, and the description of the same configuration and operation as in the conventional example is omitted.

  In the expander 430 of the fifth embodiment, the annular grooves 431 and 432 are provided on the sliding surfaces of the bearing 207 and the upper and lower ends of the first piston 209 of the intermediate plate 204, and the second groove of the bearing 208 and the intermediate plate 204 is provided. The annular grooves 433 and 434 are provided on the sliding surfaces with the upper and lower end surfaces of the piston 210, and the sealing material 435 is installed therein. The material of the sealing material 435 is the same as that of the first embodiment. Further, the engagement groove 436 in which the tip of the first vane 211 is fitted to the outer peripheral surface of the first piston 209, and the engagement groove in which the tip of the second vane 212 is fitted to the outer peripheral surface of the second piston 210. 437 is installed. The relationship between the radial width w and the eccentricity e of each piston 209, 210 and the width s of the sealing material 435 is the same as in the first embodiment.

  With such a configuration, since the sealing material 435 is provided, the oil mixes with the working fluid in the working chambers 215a, 215b, 216a, and 216b and flows out from the discharge pipe 218 for the same reason as in the first embodiment. The amount, that is, the amount of oil discharged can be greatly reduced, and the expander can be highly efficient and reliable, and the performance of the refrigeration cycle due to oil can be prevented.

  In addition, the rotation of the pistons 209 and 210 is prevented by fitting the vanes 211 and 212 into the engagement grooves 436 and 437, respectively. Therefore, the seal material 435 and the upper and lower end surfaces of the pistons 209 and 210 It is possible to reduce the wear speed of the sealing material 435 and to ensure reliability by suppressing the sliding speed.

  In the fifth embodiment, the sealing material 435 is provided for both the first piston 209 and the second piston 210, but the working chamber 216b formed on the discharge hole 206b side of the second cylinder 206 is provided. Is the lowest among all the working chambers 215a, 215b, 216a, 216b, and therefore the differential pressure between the eccentric portions 203a, 203b is large. Therefore, when the seal material 435 is installed only on the second piston 210 adjacent to the working chamber 216b, a more significant oil discharge amount reduction effect is obtained than when the seal material 435 is installed only on the first piston 209. It is done.

  In the fifth embodiment, the engagement grooves 436 and 437 are provided to prevent the first piston 209 and the second piston 210 from rotating, but the pistons 209 and 210 and the vanes 211 and 212 are provided. It goes without saying that the same effect can be obtained even if a configuration such as a swing piston is integrally formed.

  The expander of the present invention collects refrigerant expansion energy in the refrigeration cycle and is useful as power recovery means, and is also useful as energy recovery means from compressive fluid other than the refrigeration cycle.

The longitudinal cross-sectional view of the expander in Embodiment 1 of this invention 1 is a cross-sectional view taken along line D1-D1 of the expander shown in FIG. (A) Perspective view of the sealing material of the expander shown in FIG. 1 (b) Perspective view of another sealing material of the expander shown in FIG. The perspective view of the bearing of the expander, the sealing material, and the spring in Embodiment 2 of this invention The expanded longitudinal cross-sectional view of the expansion mechanism part of the expander in Embodiment 3 of this invention The expanded longitudinal cross-sectional view of the expansion mechanism part of the expander in Embodiment 4 of this invention Vertical section of an expander according to Embodiment 5 of the present invention (A) Cross section taken along line D2-D2 of the expander shown in FIG. 7 (b) Cross section taken along line D3-D3 of the expander shown in FIG. Vertical section of a conventional expander Cross section along line D1-D1 of the expander shown in FIG. Vertical section of a conventional expander (A) Cross section taken along line D2-D2 of the expander shown in FIG. 11 (b) Cross section taken along line D3-D3 of the expander shown in FIG. Enlarged longitudinal sectional view of a compression mechanism of a conventional compressor Perspective view of piston and seal material of conventional compressor

Explanation of symbols

100, 200, 400, 430 Expander 101, 201 Generator 101a, 201a Stator 101b, 201b Rotor 102, 202 Sealed container 103, 203 Shaft 103a Eccentric part 103b Axial flow path 103c Opening 103d Radial flow path 104 Cylinder 104a 205a, 206a Vane groove 104b, 206b Discharge hole 105, 106, 207, 208 Bearing 105a, 106a, 207a, 208a Oil groove 107 Piston 107a, 436, 437 Engagement groove 107b, 205b Suction hole 108 Vane 109, 213, 214 , 404 Spring 110a, 110b, 215a, 215b, 216a, 216b Working chamber 111, 217 Suction pipe 112, 218 Discharge pipe 113, 219 Oil reservoir 203a First eccentric part 2 3b 2nd eccentric part 204 Middle plate 204a Communication hole 205 1st cylinder 206 2nd cylinder 209 1st piston 210 2nd piston 211 1st vane 212 2nd vane 301 Piston 302,303 Bearing member 304 , 305, 307, 308, 403, 413, 423, 435 Sealing material 306 Swing piston 401, 402, 411, 412, 421, 422, 431, 432, 433, 434 Annular groove 403a Cut 411a, 412a An outer peripheral surface of the annular groove 413a Sealing material outer peripheral surface

Claims (7)

At least a shaft having an eccentric part;
A piston coupled to the eccentric portion of the shaft and performing eccentric rotational movement;
A cylinder having an inner surface that is cylindrical and a portion of the inner surface that is disposed in contact with the piston;
A closing member for closing both end faces of the cylinder;
A partition member that divides a crescent-shaped space constituted by the cylinder, the piston, and the closing member into a suction side space and a discharge side space;
A mechanism for preventing rotation of the piston,
An expander comprising a groove provided on a sliding surface of the closing member with the piston, and a seal member provided in the groove. A concave portion is provided on the outer peripheral surface of the piston, and the tip of the partition member is fitted into the concave portion to prevent the piston from rotating.
The expander according to claim 1. The piston and the partition member are integrally formed,
The expander according to claim 1. The width in the radial direction of the piston is greater than the value obtained by adding the width in the radial direction of the groove to twice the width of the eccentric amount of the eccentric portion of the shaft,
The expander in any one of Claims 1-3. The sealing material is pressed against the sliding surface of the piston by a spring provided in the groove of the closing member,
The expander in any one of Claims 1-4. A taper is provided on the outer peripheral side wall surface of the groove of the closing member,
The expander in any one of Claims 1-5. It is characterized by using carbon dioxide as a working fluid.
The expander according to any one of claims 1 to 6.

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