JP2005155381A - Expansion machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the heat of high-temperature and high-pressure steam supplied to an expansion chamber of an axial piston cylinder group of an expander from escaping through the piston and to ensure lubrication performance of a sliding portion between the piston and a cylinder sleeve.
SOLUTION: A piston 42 composed of a top 61 part, a skirt part 62, and a land part 63 is difficult to transfer heat by a hollow heat insulating space 64 formed therein, so that the high temperature and high pressure of the expansion chamber 43 is high. The temperature of the skirt portion 42 slidably contacting the cylinder sleeve 41 is maintained while maintaining the land portion 63 in contact with the steam in a high temperature state and minimizing the temperature drop of the high-temperature high-pressure steam to prevent the efficiency of the expander from being lowered. The lubricating performance can be ensured by suppressing. In addition, since the high-temperature and high-pressure steam in the expansion chamber 43 and the oil in the skirt portion 62 are partitioned by the piston rings 65 and 66 provided in the land portion 63, mixing of the high-temperature and high-pressure steam and the oil can be prevented.
[Selection] Figure 8

Description

  The present invention includes a casing, a rotor rotatably supported by the casing, and an axial piston cylinder group disposed on the rotor so as to surround an axis thereof, and is partitioned between a piston and a cylinder sleeve of the axial piston cylinder group. The present invention relates to an expander that rotationally drives a rotor by supplying high-temperature and high-pressure steam to the expansion chamber and lubricates sliding portions of a piston and a cylinder sleeve with oil.

Such an expander is known from Patent Document 1 below. The expander includes a first axial piston cylinder group disposed radially inward and a second axial piston cylinder group disposed radially outward. The pistons of the first axial piston cylinder group are It has a solid structure, one end of which faces the expansion chamber to which high-temperature and high-pressure steam is supplied, the other end contacts the swash plate, and the sliding portion with the cylinder sleeve is lubricated by oil. Yes.
JP 2002-256805 A

  By the way, the piston of the axial piston cylinder group of the expander is preferably maintained at a high temperature at the end facing the expansion chamber so that the high-temperature and high-pressure steam supplied to the expansion chamber does not decrease in temperature. It is desirable that the sliding portion is kept at a low temperature in order to ensure lubrication performance. However, if the piston has a solid structure, heat transfer from the high temperature side to the low temperature side is performed quickly, so the end of the expansion chamber side that should be high temperature is likely to drop, and the cylinder sleeve that should be low temperature There is a problem in that the temperature of the sliding portion is likely to rise.

  The present invention has been made in view of the above circumstances, and suppresses the heat of high-temperature and high-pressure steam supplied to the expansion chamber of the axial piston cylinder group of the expander from escaping through the piston, and the piston, cylinder sleeve, The purpose is to ensure the lubrication performance of the sliding part.

  In order to achieve the above object, according to the invention described in claim 1, a casing, a rotor rotatably supported by the casing, and an axial piston cylinder group disposed on the rotor so as to surround the axis thereof, An expansion machine that rotates the rotor by supplying high-temperature and high-pressure steam to an expansion chamber defined between the piston and cylinder sleeve of the axial piston cylinder group and lubricates the sliding portion of the piston and cylinder sleeve with oil The piston of the axial piston cylinder group includes a land portion that is exposed to the high-temperature and high-pressure steam in the expansion chamber, a top portion that contacts the swash plate, and a skirt portion that is sandwiched between the land portion and the top portion and slidably contacts the cylinder sleeve. And has a hollow heat insulating space inside, and a piston retainer provided in the land portion. Expander is proposed which is characterized in that it has partitioning the oil of the high-temperature high-pressure steam and the skirt portion of the expansion chamber grayed.

  Further, according to the invention described in claim 2, in addition to the structure of claim 1, an expander characterized in that a plurality of piston rings are provided in the longitudinal direction of the piston is proposed.

  Further, according to the invention described in claim 3, in addition to the structure of claim 2, an expander characterized in that recesses are provided between a plurality of piston rings is proposed.

  According to the invention described in claim 4, in addition to the structure of claim 1, an oil groove is provided on at least one of the outer peripheral surface of the piston skirt and the inner peripheral surface of the cylinder sleeve. An expander is proposed.

  The second land groove 63e of the embodiment corresponds to the concave portion of the present invention, and the top ring 65 and the second ring 66 of the embodiment correspond to the piston ring of the present invention.

  According to the configuration of the first aspect, the land portion is exposed to the high-temperature and high-pressure steam of the expansion chamber, the top portion is in contact with the swash plate, and the skirt portion is sandwiched between the land portion and the top portion and is in sliding contact with the cylinder sleeve. Since the pistons of the axial piston cylinder group thus made difficult to transfer heat due to the hollow heat-insulating space formed inside, the land portion that contacts the high-temperature high-pressure steam supplied to the expansion chamber is maintained at a high temperature. The lubrication performance can be ensured by suppressing the temperature rise of the skirt portion that is in sliding contact with the cylinder sleeve while minimizing the temperature drop of the high-temperature high-pressure steam to prevent the efficiency of the expander from being lowered. In addition, the piston ring provided in the land section partitions the high-temperature and high-pressure steam in the expansion chamber and the oil in the skirt section, so that the oil enters the expansion chamber and prevents the land section from being cooled. Can be prevented from entering the skirt portion side and impairing the lubricating effect of the oil.

  According to the configuration of the second aspect, since a plurality of piston rings are provided in the longitudinal direction of the piston, not only can the high-temperature and high-pressure steam blown from the land portion to the skirt portion can be more reliably prevented, but also far from the expansion chamber. By providing the piston ring on the side with the function of an oil ring, mixing of oil and high-temperature high-pressure steam can be effectively prevented.

  According to the configuration of the third aspect, since the recesses are provided between the plurality of piston rings, even when some high-temperature high-pressure steam blows through the piston ring on the expansion chamber side, The pressure difference between the expansion chamber side and the recess side is prevented from abruptly decreasing, and the piston ring is urged radially outward by the pressure difference to prevent the pressure difference from rising from the inner peripheral surface of the cylinder sleeve and the piston ring groove surface. , Sealability can be ensured.

  According to the fourth aspect of the present invention, the oil groove is provided between at least one of the outer peripheral surface of the piston skirt and the inner peripheral surface of the cylinder sleeve. The lubrication performance of the sliding surface can be improved.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 8 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of an expander, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. FIG. 4 is an enlarged view of a portion 4 of FIG. 1, FIG. 5 is an exploded perspective view of the rotor, FIG. 6 is a sectional view taken along line 6-6 in FIG. FIG. 8 is an enlarged view of 8 parts in FIG.

  The expander E of this embodiment is used in, for example, a Rankine cycle apparatus, and converts thermal energy and pressure energy of high-temperature and high-pressure steam as a working medium into mechanical energy and outputs the mechanical energy. The casing 11 of the expander E includes a casing main body 12, a front cover 15 coupled to the front opening of the casing main body 12 with a plurality of bolts 14 through a seal member 13, and a rear opening of the casing main body 12. A rear cover 18 coupled with a plurality of bolts 17 through a sealing member 16, and an oil pan 21 coupled with a plurality of bolts 20 with a lower surface opening of the casing body 12 through a sealing member 19. Consists of.

  The rotor 22 arranged to be rotatable around the axis L extending in the front-rear direction in the center of the casing 11 is supported by combination angular bearings 23, 23 provided on the front cover 15 at the front part thereof, and the rear part thereof as the casing body 12. Is supported by a radial bearing 24 provided on the surface. A swash plate holder 28 is integrally formed on the rear surface of the front cover 15, and a swash plate 31 is rotatably supported by the swash plate holder 28 via an angular bearing 30. The axis of the swash plate 31 is inclined with respect to the axis L of the rotor 22, and the inclination angle is fixed.

  The rotor 22 includes an output shaft 32 supported on the front cover 15 by combined angular bearings 23 and 23, and notches 57 and 58 (see FIGS. 4 and 8) of a predetermined width at the rear portion of the output shaft 32. Three sleeve support flanges 33, 34, 35 formed integrally, and a plurality of bolts 37... Are connected to the rear sleeve support flange 35 via a metal gasket 36, and the casing body 12 is connected by the radial bearing 24. And a heat insulating cover 40 fitted to the three sleeve support flanges 33, 34 and 35 from the front and coupled to the front sleeve support flange 33 by a plurality of bolts 39. .

  The three sleeve support flanges 33, 34, 35 are each formed with five sleeve support holes 33a, 34a, ..., 35a ... around the axis L at intervals of 72 °, and these sleeve support holes 33a, ..., Five cylinder sleeves 41 are fitted to the rear 34a, 35a,. A flange 41 a is formed at the rear end of each cylinder sleeve 41, and the flange 41 a is fitted to the metal gasket 36 in a state where the flange 41 a is fitted in a step portion 35 b formed in the sleeve support hole 35 a of the sleeve support flange 35 on the rear side. Abutting and positioning in the axial direction (see FIG. 8). A piston 42 is slidably fitted inside each cylinder sleeve 41, and the front end of the piston 42 abuts a dimple 31 a formed on the swash plate 31, and the rear end of the piston 42 and the rotor head 38 are in contact with each other. A steam expansion chamber 43 is defined between them.

  A plate-shaped bearing holder 92 is superimposed on the front surface of the front cover 15 via a seal member 91 and fixed with bolts 93... And a pump body 95 is superimposed on the front surface of the bearing holder 92 via a seal member 94. It is fixed with bolts 96. The combined angular bearings 23 and 23 are sandwiched between the step portion of the front cover 15 and the bearing holder 92 and are fixed in the direction of the axis L.

  A shim 97 having a predetermined thickness is sandwiched between a flange 32 d formed on the output shaft 32 that supports the combined angular bearings 23, 23 and an inner race of the combined angular bearings 23, 23, and is screwed onto the outer periphery of the output shaft 32. The inner race of the combined angular bearings 23, 23 is tightened by the nut 98. As a result, the output shaft 32 is positioned in the direction of the axis L with respect to the combined angular bearings 23, 23, that is, with respect to the casing 11.

  An oil passage 32 a extending on the axis L is formed inside the output shaft 32 integral with the rotor 22, and the front end of the oil passage 32 a branches in the radial direction and communicates with an annular groove 32 b on the outer periphery of the output shaft 32. At the radially inner position of the sleeve support flange 34 at the center of the rotor 22, an oil passage closing member 45 is screwed into the inner periphery of the oil passage 32a via a seal member 44, and the diameter from the oil passage 32a in the vicinity thereof. A plurality of oil holes 32 c extending outward in the direction are opened on the outer peripheral surface of the output shaft 32.

  A trochoid oil pump 49 disposed between a recess 95a formed on the front surface of the pump body 95 and a pump cover 48 fixed to the front surface of the pump body 95 with a plurality of bolts 47 through a seal member 46 is provided. The outer rotor 50 is rotatably fitted in the recess 95a, and the inner rotor 51 is fixed to the outer periphery of the output shaft 32 and meshes with the outer rotor 50. The internal space of the oil pan 21 communicates with the suction port 53 of the oil pump 49 through the oil pipe 52 and the oil passage 95b of the pump body 95, and the discharge port 54 of the oil pump 49 passes through the oil passage 95c of the pump body 95. The output shaft 32 communicates with the annular groove 32b.

  Next, the structure of the piston 42 will be described in detail with reference to FIGS.

  The piston 42 includes a top portion 61, a skirt portion 62, and a land portion 63. The top portion 61 is a member having a spherical surface portion 61 a that contacts the dimple 31 a of the swash plate 31, and is joined to the tip of the skirt portion 62 by welding. The land portion 63 and the skirt 62 are integrally formed, and a large-capacity and vacuum heat insulating space 64 is defined in the inside. An annular oil groove 62a having a slightly smaller diameter is formed in the middle of the skirt portion 62 slidably fitted to the inner peripheral surface of the cylinder sleeve 41, and the skirt portion 62 on the front side of the oil groove 62a is formed. A plurality of spiral grooves 62b... Are formed on the outer peripheral portion.

  The land portion 63 has a top land 63a on the expansion chamber 43 side and a second land 63b on the skirt portion 62 side, and a top ring groove 63c into which the top ring 65 fits between the top land 63a and the second land 63b. A second ring groove 63d into which the second ring 66 is fitted is formed between the second land 63b and the skirt portion 62, and a second land groove 63e is formed in an intermediate portion of the second land 63b. The outer diameters of the top land 63 a and the second land 63 b are slightly smaller than the outer diameter of the skirt portion 62, and between the outer peripheral surface of the top land 63 a and the second land 63 b and the inner peripheral surface of the cylinder sleeve 41. Is formed with a gap α. Therefore, the circumferential thrust load that rotates the rotor 22 is transmitted from the skirt portion 62 to the cylinder sleeve 41 without passing through the land portion 63.

  The top ring 65 disposed at a position relatively close to the top of the piston 42 (about 10% of the diameter of the piston 42) has a rectangular cross section, and the face surface that is in sliding contact with the cylinder sleeve 41 has a curved barrel. A ceramic hard film such as TiN or CrN is formed on the surface. The second ring 66 has a rectangular cross section (or a cross section with an internal bevel cut), and the face surface slidably contacting the cylinder sleeve 41 is a curved barrel face, and the surface thereof is a ceramic such as TiN or CrN. A hard coating of the system is formed. For both the top ring 65 and the second ring 66, the joint gap is set to the smallest dimension that does not contact when hot, the thickness is set as small as possible (about 3% of the diameter of the piston 42), and the initial tension is set to be small. To do.

  By applying a hard film to the top ring 65 and the second ring 66, the amount of wear can be reduced and the amount of leakage of steam can be reduced. Further, the initial tension of the top ring 65 and the second ring 66 is set small, and the thickness is reduced to reduce the pressing load on the inner peripheral surface of the cylinder sleeve 41 due to the pressure of the steam, so that the top ring 65 and the second ring 66 are reduced. The frictional force with the cylinder sleeve 41 can be reduced while improving the followability to the cylinder sleeve 41 to enhance the sealing effect.

  An annular groove 41b (see FIGS. 5 and 8) is formed on the outer periphery of the intermediate portion of the cylinder sleeve 41, and a plurality of oil holes 41c are formed in the annular groove 41b. An oil groove 62 a formed in the middle of the skirt portion 62 communicates with the oil holes 41 c of the cylinder sleeve 41.

  An annular lid member 69 is welded to the front side of the rotor head 38 or the expansion chamber 43 side connected to the rear surface of the sleeve support flange 33 on the front side of the rotor 22 by bolts 37. The heat insulating space 70 (see FIG. 8) is partitioned. The rotor head 38 is positioned in the rotational direction with respect to the rear sleeve support flange 35 by a knock pin 55.

  As shown in FIG. 1, a rotary valve 71 is provided between the rear cover 18 of the casing 11 and the cylinder head 38 of the rotor 22. The rotary valve 71 sequentially supplies the high-temperature and high-pressure steam from the steam supply pipe 67 to the five expansion chambers 43 as the rotor 22 rotates, and the low-temperature and low-pressure steam from the expansion chamber 43 passes between the main casing 12 and the rear cover 18. It is discharged into a steam discharge chamber 68 divided into two.

  The five cylinder sleeves 41 and the five pistons 42 constitute the axial piston cylinder group A of the present invention.

  Next, the operation of the expander E of the present embodiment having the above configuration will be described.

  When high-temperature and high-pressure steam generated by heating water with an evaporator is supplied from the steam supply pipe 85 to the expansion chamber 43 in the cylinder sleeve 41 through the rotary valve 71, the piston 42 fitted to the cylinder sleeve 41 is top dead. It is pushed forward from the point toward the bottom dead center, and the end portion 61 at the front end presses the dimple 31 a of the swash plate 31. As a result, a rotational torque is applied to the rotor 22 by a reaction force that the piston 42 receives from the swash plate 31. Each time the rotor 22 rotates by one fifth, high-temperature and high-pressure steam is supplied into adjacent new expansion chambers 43 and the rotor 22 is continuously rotated. The low-temperature and low-pressure steam pushed out of the expansion chamber 43 passes through the rotary valve 71 while the piston 42 that has reached the bottom dead center with the rotation of the rotor 22 is pressed against the swash plate 31 and retreats toward the top dead center. And discharged into the steam discharge chamber 68.

  As the rotor 22 rotates, an oil pump 49 provided on the output shaft 32 operates, and oil drawn from the oil pan 21 through the oil pipe 52, the oil passage 95b of the pump body 95, and the suction port 53 is discharged from the discharge port 54. The oil passage 95c of the pump body 95, the oil passage 32a of the output shaft 32, the annular groove 32b of the output shaft 32, the oil hole 32c of the output shaft 32, the annular groove 41b of the cylinder sleeve 41 and the oil hole of the cylinder sleeve 41 are discharged. 41c... Is supplied to an oil groove 62a formed in the skirt portion 62 of the piston 42. A part of the oil retained in the oil groove 62a flows into the spiral groove 62b formed in the skirt portion 62 of the piston 42, lubricates the sliding surface with the cylinder sleeve 41, and then returns to the oil pan 21. Another part of the oil lubricates the sliding surface between the top ring 65 and the second ring 66 provided on the land portion 63 of the piston 42 and the cylinder sleeve 41. Since the oil groove 62a formed in the skirt portion 62 has a function of temporarily holding the oil, the lubricating condition can be improved by supplying the oil to the sliding portions of the piston 42 and the cylinder sleeve 41 without interruption.

  Since the vacuum heat insulating space 64 is formed inside the piston 42, the heat of the high-temperature high-pressure steam supplied to the expansion chamber 43 facing the top of the piston 42 is suppressed from escaping through the piston 42, and the expansion chamber 43 The output of the expander E can be increased while minimizing the temperature drop of the high-temperature and high-pressure steam. Further, since the temperature of the top of the piston 42 is maintained at a high temperature, steam is condensed between the land portion 63 of the piston 42 and the cylinder sleeve 41, making it difficult to liquefy, improving the lubrication conditions of the land portion 63. The sealing performance and wear resistance of the top ring 65 and the second ring 66 can be improved.

  The rear side of the top ring groove 63c of the land portion 63 of the piston 42 communicates with the high-pressure expansion chamber 43 and the front side communicates with the low-pressure second land groove 63e, so that the pressure difference pushes up from the bottom of the top ring groove 63c. The top ring 65 thus formed is brought into close contact with the inner peripheral surface of the cylinder sleeve 41 and the side surface of the top ring groove 63c, thereby improving the sealing performance. Even if the high-temperature and high-pressure steam in the expansion chamber 43 blows through the top ring 65 slightly toward the second land groove 63e, the pressure difference is prevented from abruptly decreasing due to the volume of the second land groove 63e, and the tension of the top ring 65 is secured. In addition, a decrease in sealing performance can be prevented. In addition, since the second land groove 63e also has a function of holding oil, it can contribute to an improvement in lubrication performance.

  The second ring 66 has a function of an oil ring that maintains compression when high-temperature and high-pressure steam blows through the top ring 65 and scrapes off oil adhering to the inner peripheral surface of the cylinder sleeve 41. As described above, the top ring 65 and the second ring 66 provided in the land portion 63 partition the high-temperature and high-pressure steam in the expansion chamber 43 and the oil in the skirt portion 62, so that the oil enters the expansion chamber 43 side and enters the land portion 63. It is possible to prevent the oil from being cooled, and it is possible to prevent the high-temperature and high-pressure steam from entering the skirt portion 62 and damaging the lubricating effect of the oil.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, although the axial piston cylinder group A of the embodiment includes five pistons 42 and cylinder sleeves 41, respectively, the number is not limited to the embodiment.

  Moreover, although the heat insulation space 64 of the Example is evacuated, gas, such as air, may be enclosed.

  In the embodiment, the oil groove 42 a is provided on the outer peripheral surface of the piston 42, but the oil groove may be provided on the inner peripheral surface of the cylinder sleeve 41.

Vertical section of expander 2-2 sectional view of FIG. 3-3 line view of FIG. 4 enlarged view of FIG. Exploded perspective view of rotor 6-6 sectional view of FIG. Sectional view along line 7-7 in FIG. 8 enlarged view of FIG.

Explanation of symbols

11 Casing 22 Rotor 31 Swash plate 41 Cylinder sleeve 42 Piston 43 Expansion chamber 61 Top portion 62 Skirt portion 62a Oil groove 63 Land portion 63e Second land groove (concave portion)
64 Thermal insulation space 65 Top ring (piston ring)
66 Second ring (piston ring)
A Axial piston cylinder group L Axis

Claims (4)

A casing (11);
A rotor (22) rotatably supported by the casing (11);
An axial piston cylinder group (A) arranged to surround the axis (L) of the rotor (22),
The rotor (22) is rotationally driven by supplying high-temperature and high-pressure steam to the expansion chamber (43) defined between the piston (42) and the cylinder sleeve (41) of the axial piston cylinder group (A), and the piston (42 ) And an expander that lubricates the sliding portion of the cylinder sleeve (41) with oil,
The piston (42) of the axial piston cylinder group (A) includes a land portion (63) that is exposed to the high-temperature and high-pressure steam in the expansion chamber (43), a top portion (61) that contacts the swash plate (31), and a land portion. (63) and a skirt portion (62) sandwiched between the top portion (61) and slidably contacting the cylinder sleeve (41), a hollow heat insulating space (64) inside, and a land portion ( An expander characterized in that the high-temperature and high-pressure steam in the expansion chamber (43) and the oil in the skirt portion (62) are partitioned by a piston ring (65, 66) provided in 63).   The expander according to claim 1, wherein a plurality of piston rings (65, 66) are provided in the longitudinal direction of the piston (42).   The expander according to claim 2, wherein a recess (63e) is provided between the plurality of piston rings (65, 66). The expander according to claim 1, wherein an oil groove (62e) is provided on at least one of an outer peripheral surface of the skirt portion (62) of the piston (42) and an inner peripheral surface of the cylinder sleeve (41).

Images