JP2008106669A - Rotary fluid machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce mechanical loss at a slide part of a fixed member and a movable member. <P>SOLUTION: In a compressor 1, a piston 60 rotates eccentrically with respect to a cylinder 70 to change volume of a cylinder chamber C formed between the cylinder 70 and the piston 60. A cylinder side end plate part 41 slidingly contacting a tip surface 66 of the piston 60 and defining the cylinder chamber C is integrally provided in a base end side of the cylinder 70. A piston side end plate part 61 slidingly contacting tip surfaces 75, 76 of the cylinder 70 and defining the cylinder chamber C is integrally provided in a base end side of the piston 60. Coating films 67, 78, 79 for reducing friction are provided on only tip surfaces 66, 75, 76 thereof in at least one of the cylinder 70 and the piston 60. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotary fluid machine in which a fixed member and a movable member rotate relatively eccentrically.

  Conventionally, for example, a rotary fluid machine as disclosed in Patent Document 1 is known. This rotary fluid machine includes a cylinder as a fixed member and a piston as a movable member that rotates eccentrically with respect to the cylinder. A cylinder side end plate portion and a piston side end plate portion are provided on the base end side of each of the cylinder and the piston. A fluid chamber is formed between the cylinder and the piston by the tip end surface of the cylinder being in sliding contact with the piston side end plate portion and the tip end surface of the piston being in sliding contact with the cylinder end end plate portion. This rotary fluid machine compresses the fluid sucked into the fluid chamber by rotating the piston eccentrically.

  In such a rotary fluid machine, when the fluid in the fluid chamber is compressed, the internal pressure of the fluid chamber increases. When the internal pressure of the fluid chamber rises, a separation force in a direction away from each other acts on the cylinder and the piston. For this reason, if no measures are taken, the airtightness of the fluid chamber cannot be sufficiently maintained, leading to a reduction in compression efficiency.

Therefore, in the rotary fluid machine disclosed in Patent Document 1, a pressing force is applied to the back surface of the piston-side end plate portion to prevent the clearance between the piston and the cylinder from increasing, thereby ensuring the airtightness of the fluid chamber. Like to do.
JP-A-6-288358

  However, if a pressing force is applied in the direction in which the cylinder and the piston are pressed against each other against the separation force from the fluid chamber, the sliding contact portion between the tip surface of the cylinder and the piston side end plate portion, and the tip surface of the piston The frictional resistance increases at the sliding contact portion between the cylinder end plate portion and the cylinder side end plate portion.

  Therefore, as described above, when a pressing force is applied to the cylinder on the piston side, the airtightness of the fluid chamber can be secured, but on the other hand, mechanical loss due to frictional resistance at the sliding contact portion between the cylinder and the piston ( So-called thrust loss) increases.

  The present invention has been made in view of such a point, and an object thereof is to reduce mechanical loss in a sliding contact portion between a fixed member and a movable member.

  In the first invention, the movable member (60) rotates eccentrically with respect to the fixed member (70), and the fluid chamber (C) formed between the fixed member (70) and the movable member (60) is provided. The target is a rotary fluid machine that changes volume. A fixed-side end plate portion (41) that slidably contacts the distal end surface (66) of the movable member (60) and divides the fluid chamber (C) is integrally formed on the base end side of the fixed member (70). The movable end plate portion (61) is provided on the proximal end side of the movable member (60) and slidably contacts the distal end surfaces (75, 76) of the fixed member (70) to partition the fluid chamber (C). ), And at least one of the fixed member (70) and the movable member (60) has a lubricating coating (67, 67) for reducing friction only on the front end surface (66, 75, 76). 78, 79) are provided.

  In the case of the above configuration, the distal end surface (66) of the movable member (60) and the fixed side end plate portion (41) are in sliding contact with each other, and the distal end surface (75, 76) of the fixed member (70) and the movable side end plate portion ( 61) are in sliding contact with each other (hereinafter, these front end surfaces (66, 75, 76) and end plate portions (41, 61) in sliding contact with each other are also simply referred to as sliding contact portions). By providing the lubricating coating (67,78,79) on at least one tip surface (66,75,76) of the fixed member (70) and the movable member (60), the lubricating coating (67,78 , 79) can reduce the friction of the tip surfaces (66, 75, 76). Here, “reducing friction” means reducing friction as compared to the tip surface (66, 75, 76) when the lubricating coating (67, 78, 79) is not provided. As a result, between the tip surface (66,75,76) provided with the lubricating coating (67,78,79) and the end plate portion (41,61) in sliding contact with the tip surface (66,75,76) The mechanical loss can be reduced.

  Here, when the lubricating coating (67, 78, 79) is provided on the target surface, first, the lubricating coating material is applied to the surface, and then the lubricating coating material is applied to the surface. It is necessary to polish to smooth the surface. In the present invention, the lubricating coating (67, 78, 79) is provided only on the front end surface (66, 75, 76) of the fixed member (70) and / or the movable member (60), so that the polishing is easily performed. be able to.

  That is, a portion other than the distal end surface (66, 75, 76) of the fixed member (70) and / or the movable member (60), for example, a portion of the end plate portion that is in sliding contact with the distal end surface (66, 75, 76). It is also conceivable to provide it. However, a movable member (60) is integrally provided on the movable side end plate portion (61), and a fixed member (70) is integrally provided on the fixed side end plate portion (41), so that the end plate portion is polished. A polishing tool at a corner formed by the movable side end plate portion (61) and the movable member (60) or at a corner portion formed by the fixed side end plate portion (41) and the fixed member (70). And a dedicated polishing tool for polishing an intricate portion is required. Furthermore, it is necessary to move the polishing tool along the corner, and high positioning accuracy of the polishing tool is required. That is, if a lubricating film is provided on the end portion (66, 75, 76) of the end plate portion in sliding contact with the end plate surface, the workability at the time of polishing is poor and the cost is increased.

  On the other hand, in the present invention, the lubricating coating (67, 78, 79) is provided only on the front end surface (66, 75, 76) of the fixed member (70) and / or the movable member (60) protruding from the end plate portion. This makes it possible to polish the tip surface (66, 75, 76) with a simple operation and at a low cost.

  In a second aspect based on the first aspect, the movable member (60) is engaged with a support portion (64) provided at a position away from the center of eccentric rotation, and the support portion (64 ) To be eccentrically rotated around the center.

  In the case of the above configuration, the movable member (60) performs eccentric rotation while swinging around the support portion (64). As a result of intensive research, the inventor of the present application performs eccentric rotation while the movable member (60) swings (hereinafter, also simply referred to as “the movable member swings”). It has been found that the mechanical loss increases compared to a rotary fluid machine that simply performs eccentric rotation (hereinafter also referred to simply as “the movable member does not swing”) (details will be described later). That is, in the rotary fluid machine in which the movable member (60) swings, it is particularly important to reduce the mechanical loss, and as described above, the tip of the fixed member (70) and / or the movable member (60). It is very effective to provide a lubricating film (67, 78, 79) on the surface (66, 75, 76).

  In a third aspect based on the second aspect, the fixing member has an outer cylinder part (71) and an inner cylinder part (72), and the outer cylinder part (71) and the inner cylinder part (72) A cylinder (70) in which an annular fluid chamber (C) is formed, and the movable member is housed in the fluid chamber (C) in a state of being eccentric with respect to the cylinder (70). (C) is an annular piston (60) that divides the outer fluid chamber (C1) and the inner fluid chamber (C2), and the lubricating coating (67, 78, 79) is formed by the outer cylinder portion (71 ), At least one tip surface (66, 75, 76) of the inner cylinder part (72) and the piston (60).

  In the rotary fluid machine in which the movable member rotates eccentrically while swinging as described above, the part of the movable member that is away from the center of swing has a longer locus per eccentric rotation, that is, the amount of movement increases. That is, of the sliding part between the movable member and the fixed member, the part of the sliding part that is away from the support part (64) that is the center of swinging has a larger mechanical loss. In the above-described configuration, the sliding portion located on the outermost side in the radial direction on the opposite side of the support portion (64) across the center of the eccentric rotation, that is, the distal end surface (75 of the outer cylinder portion (71)). ) And the movable end plate portion (61) have the largest mechanical loss.

  By the way, in general, the configuration in which the piston (60) is a movable member is compared with the configuration in which the cylinder (70) is a movable member, compared to the outer cylinder portion (71), the piston (60), and the inner cylinder. The diameter of the portion (72) tends to increase. That is, when the diameter of the outer cylinder part (71) increases, the sliding contact part located on the outermost side in the radial direction, in which the mechanical loss is maximized, is further away from the support part (64). Will increase. Also, when the diameter of the piston (60) and the inner cylinder part (72) is increased, at least the center of eccentric rotation (66, 76) of the tip surfaces (66, 76) of the piston (60) and the inner cylinder part (72) ( The portion on the opposite side of the support portion (64) across X) has a longer distance from the support portion (64), and the mechanical loss increases. In short, when the diameters of the outer cylinder part (71), the piston (60), and the inner cylinder part (72) are increased, the mechanical loss at the sliding contact part is increased.

  Therefore, in the rotary fluid machine in which the piston (60) is a movable member, it is particularly important to reduce the mechanical loss. As described above, the outer cylinder part (71), the inner cylinder part (72), and the piston It is more effective to provide a lubricating coating (67, 78, 79) on at least one tip surface (66, 75, 76) of (60).

  In a fourth aspect based on the third aspect, the lubricating coating (78) is provided on at least the front end surface (75) of the outer cylinder part (71).

  As described above, the slidable contact portion between the distal end surface (75) of the outer cylinder portion (71) and the movable side end plate portion (61) has the longest distance from the support portion (64) that is the center of oscillation. The portion, that is, the portion with the maximum mechanical loss is included. Therefore, mechanical loss can be effectively reduced by providing the lubricating coating (78) on at least the tip surface (75) of the outer cylinder part (71).

  According to a fifth invention, in the fourth invention, the lubricating coating (66, 79) is further formed on the tip surface (66) of the piston (60) and the tip surface (76) of the inner cylinder part (72). It shall be provided.

  In the case of the above-described configuration, by providing the lubricating coating (67, 79) not only on the outer cylinder part (71) but also on the tip surfaces (66, 76) of the piston (60) and the inner cylinder part (72), Mechanical loss can be further reduced.

  According to a sixth invention, in any one of the first to fifth inventions, the front end surface (75, 76) of the fixed member (70) and the front end surface (66) of the movable member (60) are used for the lubrication. The tip surface (66,75,76) on which the coating (67,78,79) is provided is formed with a recessed groove (66a, 75a, 76a), and the lubricating coating (67,78,79) is formed. ) Is provided so as to fill the concave grooves (66a, 75a, 76a).

  In the above configuration, when the lubricating coating (67, 78, 79) is provided on the entire front end surface (66, 75, 76), the lubricating coating material is applied only to the front end surface (66, 75, 76). Therefore, it is necessary to mask the side surface with the masking member so that the lubricating coating material does not adhere to the side surface of the fixed member and / or the movable member. When the tip surface (66, 75, 76) is coated in such a masked state, the lubricating coating material does not adhere to the side surface, but may slightly adhere to the masking material. When the masking material is removed, the lubricating coating material adhering to the masking material remains as the edge of the lubricating coating (67,78,79) formed on the tip surface (66,75,76), It becomes a burr (78a) protruding from the front end surface (66, 75, 76) to the side surface side (that is, the tangential direction of the front end surface). Therefore, a step for removing the burr (78a) is further required.

  Also, in the configuration where the lubricating coating (67, 78, 79) is simply provided on the uniform tip surface (66, 75, 76), the lubricating coating (67, 78, 79) is peeled off from the edge (78b). There is a risk of doing.

  Therefore, in the above-described configuration, the groove (66a, 75a, 76a) is formed in the tip surface (66, 75, 76), and the groove (66a, 75a, 76a) is filled so as to fill the lubricating coating (67 78, 79). By doing so, it is possible to suppress the lubricating coating material from protruding in the tangential direction of the tip surface (66, 75, 76) by the both side walls of the concave groove (66a, 75a, 76a). In other words, after the lubricating coating material is applied to the concave grooves (66a, 75a, 76a), the lubricating coating (67, 78, 76, 66, 75a, 76a) that protrudes from the concave grooves (66a, 75a, 76a) to the tip surface (66, 75, 76). 79) can be polished, and as described above, it is not necessary to mask the side surfaces or remove burrs protruding from the side surfaces.

  In addition, in the configuration in which the lubricating coating is provided so as to fill the concave grooves (66a, 75a, 76a), the lubricating coating (67, 78, 79) faces the tip surface (66, 75, 76). Moreover, since the edge part is joined to the side wall of the concave groove (66a, 75a, 76a), it is possible to prevent the lubricating coating (67, 78, 79) from peeling off from the edge part.

  In a seventh aspect based on the fourth aspect, the tip surface (75) of the outer cylinder portion (71) is formed with a stepped portion (75b) in which a portion on the outer peripheral side of the inner peripheral end edge is depressed. The lubricating coating (78) is provided so as to fill the stepped portion (75b).

  In the case of the above configuration, the outer cylinder portion (71) has a fluid chamber (C) formed on the inner peripheral side thereof, while a fluid chamber (C) is not formed on the outer peripheral side thereof. Even if the coating film (78) protrudes, there is no problem, and the outer peripheral portion does not affect the airtightness of the fluid chamber (C).

  That is, in the above-described configuration, a stepped portion (75b) is formed in a portion of the front end surface (75) on the outer peripheral side of the inner peripheral edge, and the lubricating coating (78b) is filled so as to fill the stepped portion (75b). ) Can be prevented from protruding to the inner peripheral side of the outer cylinder part (71). That is, the tip surface (75) of the outer cylinder portion (71) has a portion where the step portion (75b) is not formed on the inner peripheral end portion thereof, that is, a portion forming the side wall of the step portion (75b). This prevents the non-film material for lubrication from protruding in the tangential direction of the tip surface (75).

  On the other hand, the outer peripheral edge portion of the outer cylinder portion (71) can be formed in a shape mainly intended to prevent peeling from the outer peripheral edge portion (78b) of the lubricating coating (78). For example, the outer peripheral edge (78b) of the lubricating coating (78) can be made difficult to peel by subjecting the outer peripheral edge of the tip surface (75) of the outer cylinder part (71) to R processing or the like.

  Therefore, on the front end surface (75) of the outer cylinder portion (71), the stepped portion (75b) is formed instead of the recessed groove (75a) as in the sixth invention, and the stepped portion (75b) is lubricated. By providing the coating film (78), the step of masking the side surfaces and the process of removing burrs can be reduced and the lubricating coating film (78) can be peeled off from the edge (78b), as in the sixth invention. Can be prevented.

  According to an eighth invention, in any one of the first to seventh inventions, the rotary fluid machine is connected to a refrigerant circuit that performs a refrigeration cycle, and compresses carbon dioxide filled in the refrigerant circuit as a refrigerant. Or it shall be inflated.

  In the case of the above configuration, the high pressure of the refrigeration cycle is usually set to a value higher than the critical pressure of carbon dioxide. That is, in the configuration using the carbon dioxide flow as the refrigerant, the internal pressure of the fluid chamber (C) is relatively high, so that the pressing force applied to the movable member (60) is set large, and the movable member (60) And the thrust force between the fixing member and the fixing member (70) also tends to increase. Therefore, the present invention that reduces the mechanical loss becomes more effective.

  According to the present invention, by providing the lubricating coating (67, 78, 79) on at least one of the tip surfaces (66, 75, 76) of the fixed member (70) and the movable member (60), the tip surface ( 66, 75, 76) can be reduced, and mechanical loss between the tip surface (66, 75, 76) and the end plate portion (41, 61) can be reduced. Further, by forming the lubricating coating (67, 78, 79) only on the tip surface (66, 75, 76), workability when providing the lubricating coating (67, 78, 79) is improved. And cost can be reduced.

  According to the second invention, since the rotary fluid machine in which the movable member (60) swings has a larger mechanical loss than the rotary fluid machine in which the movable member does not swing, the movable member (60) does not swing. In a rotating fluid machine that moves, the lubricating film (67, 78, 79) is provided on the front end surface (66, 75, 76) of the fixed member (70) and / or the movable member (60) to reduce mechanical loss. Reduction is particularly effective.

  According to the third invention, the rotary fluid machine in which the cylinder (70) is a fixed member and the piston (60) is a movable member is a rotary fluid machine in which the cylinder is a movable member and the piston is a fixed member. Since mechanical loss tends to increase compared to a machine, in a rotary fluid machine in which the cylinder (70) is a fixed member and the piston (60) is a movable member, the lubricating coating (67, 78, 79) may be provided on at least one tip surface (66, 75, 76) of the outer cylinder part (71), the inner cylinder part (72), and the piston (60) to further reduce mechanical loss. It is valid.

  According to the fourth invention, the tip surface (75) of the outer cylinder part (71) including the part where the distance from the (64) which is the center of oscillation is the longest, that is, the part where the mechanical loss is maximum. By providing the lubricating coating (78), mechanical loss can be effectively reduced.

  According to the fifth aspect of the invention, in addition to the tip surface (75) of the outer cylinder portion (71), the lubricating coating (66, 76) is also applied to the tip surfaces (66, 76) of the piston (60) and the inner cylinder portion (72). 67, 79), the mechanical loss can be further reduced.

  According to the sixth and seventh inventions, the concave groove (66a, 75a, 76a) or the stepped portion is formed in the tip end surface (66, 75, 76), and the concave groove (66a, 75a, 76a) Alternatively, by providing the lubricating coating (67, 78, 79) so as to fill the stepped portion (75b), the process of masking the side surfaces of the fixed member and / or the movable member and the step of removing burrs can be reduced and lubrication can be performed. The coating (67, 78, 79) can be prevented from peeling off from the edge (78b).

  According to the eighth aspect of the invention, when carbon dioxide is used as the refrigerant, the mechanical force between the movable member and the fixed member tends to increase, so that the tip surface of at least one of the fixed member and the movable member is lubricated. It is further effective to reduce the mechanical loss by providing a coating film.

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

Embodiment 1 of the Invention
A first embodiment of the present invention will be described.

  The rotary compressor (1) of the present embodiment is provided, for example, in a refrigerant circuit of a refrigerator filled with carbon dioxide as a refrigerant and used to compress carbon dioxide as a refrigerant.

  As shown in FIG. 1, the rotary compressor (1) of the present embodiment is configured as a so-called hermetic type. The rotary compressor (1) includes a casing (10) formed in a vertically long sealed container shape. The casing (10) includes a cylindrical portion (11) formed in a vertically long cylindrical shape and a pair of end plate portions (12, 12) formed in a bowl shape and closing both ends of the cylindrical portion (11). Has been. The cylindrical portion (11) is provided with a penetrating suction pipe (14), and the upper end plate portion (12) is provided with a penetrating discharge pipe (15).

  Inside the casing (10), a compression mechanism (20) and an electric motor (30) are arranged in order from the bottom to the top. Further, a drive shaft portion (33) extending in the vertical direction is provided inside the casing (10). The compression mechanism (20) and the electric motor (30) are connected via a drive shaft portion (33). In the rotary compressor (1) of the present embodiment, the refrigerant compressed by the compression mechanism (20) is discharged into the internal space of the casing (10), and then passes through the discharge pipe (15) from the casing (10). It is a so-called high-pressure dome type that is sent out. That is, the inside of the casing (10) is a high-pressure space (19).

  The drive shaft portion (33) includes a main shaft portion (33a) and an eccentric portion (33b). The drive shaft (33) is rotationally driven by the electric motor (30) about the rotation axis (X) that is the axis of the main shaft (33a). The eccentric part (33b) is provided at a position near the lower end of the drive shaft part (33), and is formed in a cylindrical shape having a larger diameter than the main shaft part (33a). The eccentric part (33b) has an axis that is eccentric by a predetermined amount from the rotation axis (X) of the main shaft part (33a). Although not shown, an oil supply passage extending upward from the lower end of the drive shaft portion (33) is formed in the drive shaft portion (33). The lower end portion of the oil supply passage constitutes a so-called centrifugal pump. Lubricating oil collected at the bottom of the casing (10) is supplied to each sliding portion of the compression mechanism (20) through the oil supply passage.

  The electric motor (30) includes a stator (31) and a rotor (32). The stator (31) is fixed to the inner wall of the cylindrical portion (11) of the casing (10). The rotor (32) is disposed inside the stator (31) and connected to the main shaft portion (33a) of the drive shaft portion (33).

  The compression mechanism (20) includes an upper housing (40), a lower housing (50), and a piston (60). In the compression mechanism (20), the piston (60) is accommodated in a space surrounded by the upper housing (40) and the lower housing (50).

  The upper housing (40) has a cylinder side end plate portion (41) and a cylinder (70).

  The cylinder side end plate portion (41) is formed in a disc shape, and the outer diameter is substantially equal to the inner diameter of the casing (10). The cylinder side end plate portion (41) is fixed to the cylindrical portion (11) of the casing (10) by welding or the like. A bearing portion (42) that supports the main shaft portion (33a) of the drive shaft portion (33) is formed through the center portion of the cylinder side end plate portion (41). The main shaft portion (33a) is rotatably inserted into the bearing portion (42).

  The cylinder (70) has cylindrical outer and inner cylinder portions (71, 72). The inner diameter of the outer cylinder part (71) is larger than the outer diameter of the inner cylinder part (72), and the inner cylinder part (72) is located inside the outer cylinder part (71). The base end portions of the outer and inner cylinder portions (71, 72) are formed integrally with the cylinder side end plate portion (41). These outer and inner cylinder parts (71, 72) are provided so that their axis centers coincide with the axis of the main shaft part (33a) of the drive shaft part (33) (that is, the axis of the bearing part (42)). It has been.

  A cylinder chamber (C) is formed between the outer cylinder part (71) and the inner cylinder part (72) as shown in FIG. The cylinder chamber (C) has an annular shape in cross section (that is, a cross section orthogonal to the axial direction of the cylinder (70)).

  A blade (73) extending across the cylinder chamber (C) is provided between the outer cylinder part (71) and the inner cylinder part (72). Specifically, the blade (73) is formed in a flat plate shape extending in the radial direction of the outer and inner cylinder portions (71, 72) from the inner peripheral surface of the outer cylinder portion (71) to the outer peripheral surface of the inner cylinder portion (72). The outer and inner cylinder parts (71, 72) are integrally formed. In addition, the blade (73) is in a state of protruding from the front surface (the surface on which the outer and inner cylinder portions (71, 72) are provided) of the cylinder side end plate portion (41). 41) is also integrally formed.

  The outer cylinder part (71) is formed with a suction port (74) penetrating in the radial direction, and a suction pipe (14) (not shown in FIGS. 2 and 3) is inserted into the suction port (74). Has been. That is, the suction pipe (14) and the cylinder chamber (C) are in communication.

  Furthermore, the eccentric part (33b) of the drive shaft part (33) is located in the inner space (77) of the inner cylinder part (72).

  The lower housing (50) has a flat plate portion (51) and a peripheral wall portion (52).

  The flat plate portion (51) is formed in a disc shape and has an outer diameter slightly smaller than the inner diameter of the casing (10). The lower housing (50) is connected to the upper housing (40) with a bolt or the like. A bearing portion (53) that supports the main shaft portion (33a) of the drive shaft portion (33) is formed through the central portion of the flat plate portion (51). The main shaft portion (33a) is rotatably inserted into the bearing portion (53). Further, the flat plate portion (51) is provided with an annular base portion (54) projecting toward the upper housing (40) so as to surround the bearing portion (53). The annular pedestal (54) is formed with a concave groove over the entire circumference, and an annular seal ring (55) is fitted into the concave groove. The annular base (54) and the seal ring (55) are provided concentrically with the bearing (53) (the rotation shaft (X) of the main shaft (33a) of the drive shaft (33)). Rather, it is eccentric with respect to the bearing portion (53) in the direction of the high pressure chamber (C1-Hp, C2-Hp) at the end of the compression stroke described later.

  The peripheral wall portion (52) is formed in a cylindrical shape extending from the peripheral edge portion of the flat plate portion (51) to the upper housing side. The inner diameter of the peripheral wall portion (52) is larger than the inner diameter of the outer cylinder portion (71). That is, in a state where the lower housing (50) is connected to the upper housing (40), the inner peripheral edge of the outer cylinder (71) protrudes radially inward of the peripheral wall (52).

  The piston (60) has a cylindrical shape, and a piston side end plate portion (61) is integrally formed on the base end side (the lower surface side in FIG. 1). The piston (60) has an inner diameter larger than the outer diameter of the inner cylinder part (72) and an outer diameter smaller than the inner diameter of the outer cylinder part (71). Further, as shown in FIG. 2, the piston (60) has a C-shape in which a part of a cylinder is divided by a dividing portion (63) in a plan view. A rocking bush (64), which will be described in detail later, is rotatably supported by the dividing portion (63).

  The piston-side end plate portion (61) is formed in a disc shape, and its outer peripheral edge portion is formed so as to protrude outward in the radial direction from the piston (60). The outer diameter of the piston side end plate portion (61) is larger than the inner diameter of the outer cylinder portion (71), and even if the piston (60) rotates eccentrically in the cylinder chamber (C), the outer cylinder portion ( 71) is set to a size that is always in sliding contact with the tip surface (the lower surface in FIG. 1) (75).

  In addition, a bearing portion (62) that is rotatably fitted to the eccentric portion (33b) of the drive shaft portion (33) is formed through the central portion of the piston side end plate portion (61). The piston (60) is provided such that its axis coincides with the axis of the eccentric part (33b) of the drive shaft part (33) (that is, the axis of the bearing part (62)).

  The piston (60) configured as described above is configured so that the bearing portion (62) is connected to the inner cylinder portion (62) when the bearing portion (62) is fitted to the eccentric portion (33b) of the drive shaft portion (33). 72) is accommodated in the inner space (77), and the piston (60) is accommodated in the cylinder chamber (C). At this time, the tip surface of the piston (60) (the surface facing the cylinder end plate portion (41)) (66) is in sliding contact with the cylinder end plate portion (41), while the inner and outer cylinder portions (71, 72) The front end surface (surface facing the piston side end plate portion (61)) (75, 76) is in sliding contact with the piston side end plate portion (61). As a result, the cylinder chamber (C) includes a cylinder side end plate portion (41), a piston side end plate portion (61), an outer cylinder portion (71) and an outer cylinder chamber (C1) surrounded by the piston (60), A side end plate portion (41), a piston side end plate portion (61), a piston (60), and an inner cylinder chamber (C2) surrounded by the inner cylinder portion (72) are partitioned.

  As shown in FIG. 2, the piston (60) has an outer peripheral surface that is in sliding contact with the inner peripheral surface of the outer cylinder portion (71) at one location, and an inner peripheral surface that is in contact with the outer peripheral surface of the inner cylinder portion (72). It is in sliding contact with the point. The sliding contact location between the piston (60) and the outer cylinder portion (71) is relative to the sliding contact location between the piston (60) and the inner cylinder portion (72). On the opposite side of the axis), that is, at a position where the phase is shifted by 180 °.

  Further, in a state where the piston (60) is housed in the cylinder chamber (C), the blade (73) is inserted through the dividing portion (63) of the piston (60). As described above, the swinging bush (64) is inserted into the dividing portion (63). The swing bush (64) is composed of a pair of bush pieces (64a, 64a). The bush pieces (64a, 64a) are small pieces in which the outer surface is formed as an arc surface and the inner surface is formed as a flat surface. The end surface of the dividing portion (63) of the piston (60) is an arc surface and is in sliding contact with the outer surface of the bush piece (64a, 64a). That is, the pair of bush pieces (64a, 64a) is disposed in the dividing portion (63) so that the inner side surfaces thereof face each other. The blade (73) is inserted into the space between the opposing inner side surfaces of both bush pieces (64a, 64a), and the inner side surfaces of both bush pieces (64a, 64a) and the blade (73) are in sliding contact. .

  In other words, the swing bush (64) is configured to freely advance and retract in the direction of the inner surface of the blade (73) with the blade (73) sandwiched therebetween. In addition, the piston (60) is configured to freely swing with respect to the swing bush (64) via the dividing portion (63). That is, the piston (60) is engaged with the swing bush (64), and the swing bush (64) constitutes a support portion.

  The outer cylinder chamber (C1) and the inner cylinder chamber (C2) are each divided into a high pressure chamber (C1-Hp, C2-Hp) and a low pressure chamber (C1-Lp, C2-Lp) by a blade (73). ing.

  The suction port (74) formed in the outer cylinder part (71) is formed to open to the low pressure chamber (C1-Lp) in the vicinity of the blade (73). The piston (60) has a position corresponding to the suction port (74) at the low pressure chamber (C1-Lp) of the outer cylinder chamber (C1) and the low pressure chamber (C2-Lp) of the inner cylinder chamber (C2). A through-hole (65) that communicates with each other is formed through. That is, the refrigerant flowing into the low pressure chamber (C1-Lp) of the outer cylinder chamber (C1) from the suction pipe (14) through the suction port (74) passes through the through hole (65) to the inner cylinder chamber (C2 ) Also flows into the low pressure chamber (C2-Lp).

  On the other hand, as shown in FIG. 2, the upper housing (40) is formed with an outer discharge port (43) and an inner discharge port (44) for discharging the compressed refrigerant. The inner discharge port (44) opens to the inner cylinder chamber (C1) near the blade (73) so that the outer discharge port (43) opens to the high pressure chamber (C1-Hp) of the outer cylinder chamber (C1) near the blade (73). It is formed through the cylinder end plate (41) so as to open to the high pressure chamber (C2-Hp) of C2). At the downstream ends of these outer and inner discharge ports (43, 44), reed valves are provided as discharge valves (not shown) that open and close the outer and inner discharge ports (43, 44).

  A muffler (45) is attached to the side of the upper housing (40) opposite to the lower housing (50) (that is, the electric motor (30) side). The muffler (45) is provided so as to cover the upper housing (40) from the side opposite to the lower housing (50), and forms a discharge space (46) between the upper housing (40). The refrigerant discharged from the outer and inner discharge ports (43, 44) is once discharged into the discharge space (46), passes through the gap between the muffler (45) and the bearing portion (42), and enters the casing (10). Flows into the high pressure space (19). That is, the muffler (45) has a silencing function for the discharge gas discharged from the compression mechanism (20).

  In the state where the piston (60) is housed in the cylinder chamber (C), as shown in FIG. 3, the back surface of the piston side end plate portion (61) has an annular base portion ( The seal ring (55) provided in 54) is in contact. With this seal ring (55), the space between the flat plate portion (51) of the lower housing (50) and the piston side end plate portion (61) is separated from the inner gap (57) inside the seal ring (55), It is divided into an outer gap (58) outside the seal ring (55).

  Since the inner gap (57) is filled with high-pressure lubricating oil supplied through the oil supply passage of the drive shaft (33), the internal pressure of the inner gap (57) is the refrigerant discharged from the compression mechanism (20). The pressure (discharge pressure) is almost the same. The outer clearance (58) communicates with the suction port (74) through a communication path (not shown). Specifically, the communication path includes a valve mechanism (for example, a ball valve and a spring) that opens and closes at a predetermined intermediate pressure that is lower than the discharge pressure and higher than the pressure of the refrigerant sucked into the compression mechanism (20) (suction pressure). It is made up of. The outer gap (58) is separated from the inner gap (57) by a seal ring (55), but high-pressure lubricating oil flows from the gap between the seal ring (55) and the piston side end plate (61). In some cases, the internal pressure rises. When the internal pressure of the outer gap (58) reaches a predetermined pressure, the valve mechanism is opened, and the outer gap (58) and the suction port (74) communicate with each other. Thus, the outer gap (58) has a predetermined intermediate pressure that is lower than the discharge pressure and higher than the suction pressure. The seal ring (55) has a function of applying a pressing force to the piston (60) in addition to a function of partitioning the inner gap (57) and the outer gap (58). That is, the piston (60) is pressed toward the cylinder (70) by the internal pressure of the inner gap (57) and the outer gap (58) and the pressing force of the seal ring (55).

  Thus, in the configuration in which the piston (60) is pressed against the cylinder (70), a thrust force (axial force) acts on the sliding contact portion between the piston (60) and the cylinder (70). Therefore, the sliding contact surfaces of the piston (60) and the cylinder (70) are coated to reduce thrust loss.

  Specifically, as shown in FIG. 3, a piston-side concave groove (66a) is formed on the tip surface (66) of the piston (60) that is in sliding contact with the cylinder-side end plate portion (41). A coating film (67) is provided so as to fill the side groove (66a). On the other hand, the front end surface (75) of the outer cylinder portion (71) and the front end surface (76) of the inner cylinder portion (72) that are in sliding contact with the piston side end plate portion (61) are respectively provided with an outer concave groove (75a) and an inner side. A concave groove (76a) is formed, and a coating film (78, 79) is provided so as to fill the outer and inner concave grooves (75a, 76a). These coating films (67, 78, 79) constitute a lubricating film.

  These piston side concave groove (66a), outer concave groove (75a) and inner concave groove (76a) have pistons (60), outer cylinder part (71) and inner cylinder part (72) on both side walls from the bottom wall, respectively. Inclined so as to spread outward (that is, so as to widen the groove width) toward the front end surface (66, 75, 76). 1 and 3, the piston-side concave groove (66a), the outer concave groove (75a), and the inner concave groove (76a) are drawn with exaggerated depths. The actual depth of the concave grooves (66a, 75a, 76a) is several tens of μm.

  As shown in FIG. 2, the piston-side concave groove (66 a) has a C-shaped piston (60) on the front end surface (66) of the piston (60) in plan view along the circumferential direction of the piston (60). It is formed in a letter shape. Further, the outer and inner concave grooves (75a, 76a) are formed over the entire circumference on the front end surface (75) of the outer cylinder portion (71) and the front end surface (76) of the inner cylinder portion (72), respectively. And formed in an annular shape in plan view.

  In the piston side ditch (66a), outer ditch (75a) and inner ditch (76a) thus configured, the piston side ditch (66a), outer ditch (75a) and inner ditch are arranged. A coating film (67, 78, 79) is provided so as to fill (76a). That is, the coating film (67, 78, 79) is provided substantially flush with the tip surface (66, 75, 76).

  The coating film (67) is first coated with a coating material so as to fill the piston-side concave groove (66a) in the piston-side concave groove (66a). At this time, the coating material is applied in the piston-side concave groove (66a) to the extent that it protrudes from the tip surface (66) of the piston (60). Then, by polishing the portion of the coating material that protrudes from the tip surface (66) of the piston (60), the coating film (67) is formed substantially flush with the tip surface (66) of the piston (60). . As the coating material, a material capable of improving the slidability of the tip surface (66) of the piston (60), that is, the coating film of the tip surface (66) of the piston (60) in the state after polishing. A material having a lower friction coefficient than that of the portion other than (67) (the portion formed of the material of the piston (60) main body) can be used. For example, fluororesin, DLC (Diamond like Carbon), ceramic, or the like can be used as the coating material.

  The coating films (78, 79) are also formed in the outer concave groove (75a) and the inner concave groove (76a).

  These coating films (67, 78, 79) are in sliding contact with the cylinder side end plate portion (41) and the piston side end plate portion (61).

-Driving action-
Next, the operation of the compressor (1) will be described.

  When the electric motor (30) is driven, the rotation of the rotor (32) is transmitted to the piston (60) of the compression mechanism (20) via the drive shaft portion (33). Then, the swinging bush (64) moves back and forth (reciprocating motion) along the blade (73), and the piston (60) swings with respect to the swinging bush (64). At that time, the swinging bush (64) substantially makes surface contact with the piston (60) and the blade (73). Then, the piston (60) rotates eccentrically with respect to the drive shaft (33) while swinging with respect to the outer cylinder (71) and the inner cylinder (72), and the compression mechanism (20) performs a predetermined compression operation. I do.

  In plan view, the eccentric rotation angle of the piston (60) is a straight line extending in the radial direction from the rotation axis (X) of the drive shaft (33) and passing through the swing center of the swing bush (64) in plan view. The axis of the piston (60) (the axis of the eccentric part (33b)) is located at the center of the piston (60) on the line connecting the rotating shaft (X) and the swinging bush (64). The eccentric rotation angle at the point of time is 0 °. (A) shows the state where the eccentric rotation angle of the piston (60) is 0 ° or 360 °, (B) shows the state where the eccentric rotation angle of the piston (60) is 90 °, and (C) shows the piston (60 60) shows the state where the eccentric rotation angle is 180 °, and FIG. 4D shows the state where the eccentric rotation angle of the piston (60) is 270 °.

  Specifically, in the outer cylinder chamber (C1), the volume of the low-pressure chamber (C1-Lp) is almost the minimum in the state of FIG. 4 (B), from which the drive shaft portion (33) rotates clockwise in the figure. Then, when the volume of the low pressure chamber (C1-Lp) increases with the change to the state of FIG. 4 (C) to FIG. 4 (A), the refrigerant flows into the suction pipe (14) and the suction port ( 74) and is sucked into the low pressure chamber (C1-Lp).

  When the drive shaft portion (33) makes one rotation and returns to the state of FIG. 4 (B), the suction of the refrigerant into the low pressure chamber (C1-Lp) is completed. The low-pressure chamber (C1-Lp) is now a high-pressure chamber (C1-Hp) in which the refrigerant is compressed, and a new low-pressure chamber (C1-Lp) is formed across the blade (73). When the drive shaft portion (33) further rotates, the suction of the refrigerant is repeated in the low pressure chamber (C1-Lp), while the volume of the high pressure chamber (C1-Hp) decreases, and the high pressure chamber (C1-Hp) The refrigerant is compressed. When the pressure in the high pressure chamber (C1-Hp) reaches a predetermined value and the differential pressure from the discharge space (46) reaches a set value, the discharge valve is opened by the high pressure refrigerant in the high pressure chamber (C1-Hp), and the high pressure refrigerant Is discharged into the discharge space (46) and flows out from the muffler (45) into the high-pressure space (19) in the casing (10).

  In the inner cylinder chamber (C2), the volume of the low-pressure chamber (C2-Lp) is almost the minimum in the state of FIG. 4 (D), and from here the drive shaft (33) rotates clockwise in FIG. When the volume of the low pressure chamber (C2-Lp) increases as the state changes from (A) to FIG. 4 (C), the refrigerant flows into the suction pipe (14), the suction port (74), and It is sucked into the low pressure chamber (C2-Lp) of the inner cylinder chamber (C2) through the through hole (65).

  When the drive shaft portion (33) makes one revolution and again enters the state of FIG. 4 (D), the suction of the refrigerant into the low pressure chamber (C2-Lp) is completed. The low-pressure chamber (C2-Lp) is now a high-pressure chamber (C2-Hp) in which the refrigerant is compressed, and a new low-pressure chamber (C2-Lp) is formed across the blade (73). When the drive shaft (33) further rotates, the suction of the refrigerant is repeated in the low pressure chamber (C2-Lp), while the volume of the high pressure chamber (C2-Hp) decreases, and the high pressure chamber (C2-Hp) The refrigerant is compressed. When the pressure in the high-pressure chamber (C2-Hp) reaches a predetermined value and the differential pressure from the discharge space (46) reaches a set value, the discharge valve is opened by the high-pressure refrigerant in the high-pressure chamber (C2-Hp), and the high-pressure refrigerant Is discharged into the discharge space (46) and flows out from the muffler (45) into the high-pressure space (19) in the casing (10).

  The high-pressure refrigerant compressed in the outer cylinder chamber (C1) and the inner cylinder chamber (C2) and flowing into the high-pressure space (19) in the casing (10) is discharged from the discharge pipe (15) and is condensed in the refrigerant circuit. After passing through the expansion stroke and the evaporation stroke, it is sucked into the compressor (1) again.

  Thus, when the piston (60) compresses the refrigerant while rotating eccentrically with respect to the cylinder (70), the piston (60) includes the seal ring (55), the inner gap (57), and the outer gap (58). A pressing force is applied to the cylinder (70) by the internal pressure. On the other hand, a separation force acts on the piston (60) in a direction away from the cylinder (70) by the internal pressure of the cylinder chamber (C). And in order to ensure the airtightness of the cylinder chamber (C), the pressing force is set to be larger than the separation force, and the difference between the pressing force and the separation force is used as a thrust force as a piston ( 60) and the cylinder (70) sliding contact, specifically between the tip surface (66) of the piston (60) and the cylinder end plate (41), the tip surface (75) of the outer cylinder (71) Between the front end surface (76) of the inner cylinder part (72) and the piston side end plate part (61). With this thrust force acting, the piston (60) and the cylinder (70) slide relative to each other and rotate eccentrically, so the tip surface (66) of the piston (60) and the cylinder end plate (41) And between the tip surfaces (75, 76) of the outer and inner cylinder parts (71, 72) and the piston side end plate part (61).

  In particular, since the compression mechanism (20) rotates eccentrically while the piston (60) swings, the thrust loss is larger than a compression mechanism in which the piston (60) does not swing.

  Specifically, when the piston (60) is simply eccentrically rotated, the locus of each part in the piston (60) and the piston side end plate (61) during the eccentric rotation of the piston (60) is As shown in FIG. 5, each part has the same length.

  On the other hand, when the piston (60) rotates eccentrically while swinging, the locus of each part in the piston (60) and the piston side end plate (61) during the eccentric rotation of the piston (60) is As shown in FIG. 6, the distance from the rocking bush (64) that becomes the rocking center is longer.

  When the length of the trajectory per eccentric rotation of each part in the piston (60), that is, the movement amount is averaged, the compression mechanism (20) in which the piston (60) swings is more suitable for the piston (60 ) Increases the amount of movement per one eccentric rotation compared to a compression mechanism that does not swing. This means that the compression mechanism (20) in which the piston (60) swings has a larger thrust loss per eccentric rotation than the compression mechanism in which the piston (60) does not swing.

  A large amount of movement per one eccentric rotation means that the sliding speed is high. That is, from the viewpoint of the sliding speed of each part in the piston (60), the compression mechanism (20) in which the piston (60) swings is compared with a compression mechanism in which the piston (60) does not swing. Thus, the sliding speed is fast and the thrust loss per unit time is large.

  Further, in the compression mechanism (20), the cylinder (70) is a fixed member, and the piston (60) is a movable member. Thus, when the piston (60) rotates eccentrically, it fits into the inner space (77) of the inner cylinder part (72) of the cylinder (70) and the eccentric part (33b) of the drive shaft part (33). It is necessary to secure a space that allows the bearing (62) of the piston (60) to rotate eccentrically with the rotation of the drive shaft (33). When the space of the inner space (77) of the inner cylinder part (72) becomes larger, the cylinder chamber (C) becomes larger in the radial direction accordingly. As a result, the diameters of the piston (60), the outer cylinder part (71) and the inner cylinder part (72) are also increased.

  On the other hand, in the case of the compression mechanism (220) in which the piston (260) is a fixed member and the cylinder (270) is a movable member, as in the compression mechanism according to the second embodiment described later, the inner cylinder portion (272) is driven. In order to fit the eccentric part (33b) of the shaft part (33), as described above, no space is provided inside the inner cylinder part (72). As a result, the cylinder chamber (C) of the compression mechanism (220) in which the cylinder (270) rotates eccentrically has the same volume as the cylinder chamber (C) of the compression mechanism (20) in which the piston (60) rotates eccentrically. However, the radial dimension is small, and the radial dimension of the piston (260), the outer cylinder part (271), and the inner cylinder part (272) is also small.

  As can be seen from FIG. 6, the radially outer portion of the piston (60) and the piston side end plate portion (61) has a greater distance from the swing bush (64). The amount of movement has increased. That is, as the diameters of the piston (60) and the piston side end plate portion (61) become larger, the portion where a large thrust loss occurs increases. Therefore, the compression mechanism (20) in which the piston (60) rotates eccentrically is compared with the compression mechanism (220) in which the cylinder (270) rotates eccentrically (see the second embodiment). ) In the radial direction, the thrust loss per one eccentric rotation is increased.

  In addition, the separating force acting on the piston (60) is the portion of the piston (60) on the high pressure chamber (C1-Hp, C2-Hp) side that performs the compression stroke and the discharge stroke, particularly the outer or inner discharge port ( 43, 44) increases just before the discharge valve is opened, at the part that divides the high-pressure chamber (C1-Hp, C2-Hp). Therefore, the action point (F) of the separation force acting on the piston (60) is biased toward the high pressure chamber (C1-hp, C2-Hp) side as shown in FIG. Thus, when the separating force acting on the piston (60) acts at a position eccentric with respect to the rotation axis (X), the piston side end plate portion (61) and the front end surface (75) of the outer cylinder portion (71) The slidable contact portion (A) opposite to the separation force acting point (F) across the rotation axis (X) in the slidable contact portion (the region surrounded by the one-dot chain line in FIG. 2) Acts in the opposite direction, that is, in the direction in which the piston (60) is pressed against the cylinder (70), as a thrust force. That is, the sliding contact portion (A) of the piston side end plate portion (61) is a portion where the thrust loss is large from the viewpoint of the amount of movement per eccentric rotation as described above (see FIG. 6). Also, the thrust loss is a part where the separation force acts eccentrically.

  As described above, with respect to the thrust force described above, in the compression mechanism (20) according to the first embodiment, the tip surface (66) of the piston (60), the tip surface (75) of the outer cylinder part (71), and the inner side The coating films (67, 78, 79) are provided on the tip surface (76) of the cylinder part (72), respectively. By doing so, the friction coefficient of the tip surface (66, 75, 76) can be reduced, so that the thrust loss can be reduced.

-Effect of Embodiment 1-
Therefore, according to the first embodiment, the tip surface (66) of the piston (60), the tip surface (75) of the outer cylinder portion (71), and the tip surface (76) of the inner cylinder portion (72), respectively. By providing the coating film (67, 78, 79), the thrust loss of the compressor (1) can be reduced.

  In the compression mechanism (20), any one of the tip surface (66) of the piston (60), the tip surface (75) of the outer cylinder portion (71), and the tip surface (76) of the inner cylinder portion (72) Thrust loss can be further reduced by providing a coating film (67, 78, 79) on all of the tip surface of the film instead of providing a coating film.

  Further, the compression mechanism (20) is configured such that the piston (60) rotates eccentrically while swinging, and the thrust loss is less than that of the compression mechanism where the movable member does not swing and only rotates eccentrically. Since it is large, it is particularly effective to reduce the thrust loss by providing the coating film (67, 78, 79).

  Furthermore, in the compression mechanism (20), the cylinder (70) is a fixed member, the piston (60) is a movable member, the cylinder (270) is a movable member, and the piston (260) is Compared with the compression mechanism (220) according to the second embodiment, which will be described later, which is a fixing member, the radial dimension of the piston (60) and the outer and inner cylinder parts (71, 72) is large, and the thrust loss is large. It is more effective to reduce the thrust loss by providing the coating film (67, 78, 79).

  In addition, in the compression mechanism (20), as described above, of the distal end surface (75) of the outer cylinder portion (71) and the piston side end plate portion (61) sliding with the distal end surface (75), There is a large thrust loss due to the separation from the oscillation center in the opposite part (A) across the high pressure chamber (C1-Hp, C2-Hp) and the rotating shaft (X) at the end of the compression stroke. In addition, a large thrust loss occurs due to the eccentric force acting as an eccentric force, and a very large thrust loss is generated when these are combined. Therefore, it is very effective to reduce the thrust loss by providing the coating film (67, 78, 79).

  The coating film (67, 78, 79) includes the tip surface (66) of the piston (60), the tip surface (75) of the outer cylinder portion (71), and the tip surface (76) of the inner cylinder portion (72). Any one of them may be provided. Thrust loss can be reduced by providing the coating film (67, 78, 79) on any one of the tip surfaces (66, 75, 76). However, as described above, the portion that is farther away from the center of the swing is increased in the radially outer portion and the thrust loss is increased, and the increase in the thrust loss due to the eccentric action of the separating force is the diameter. Since it occurs in the outer portion in the direction, it is preferable to provide the coating film (78) at least on the tip surface (75) of the outer cylinder portion (71) located on the outermost radial direction. That is, of the tip surface (66) of the piston (60), the tip surface (75) of the outer cylinder portion (71), and the tip surface (76) of the inner cylinder portion (72), the tip surface of the outer cylinder portion (71) Providing the coating film (78) on (75) can most effectively reduce the thrust loss.

  In addition, the coating film (67, 78, 79) is provided only on the tip surface (66, 75, 76) of the piston (60), the outer cylinder part (71) and the inner cylinder part (72). The workability when forming the coating film (67, 78, 79) can be improved and the cost can be reduced.

  Specifically, in order to reduce the thrust loss, the cylinder side end plate portion (41) in which the tip surfaces (66, 75, 76) of the piston (60), the outer cylinder portion (71) and the inner cylinder portion (72) are in sliding contact with each other. ) And a piston-side end plate portion (61) may be provided with a coating film. However, for example, in the cylinder side end plate portion (41), the sliding contact portion with which the front end surface (66) of the piston (60) is in sliding contact is sandwiched between the outer cylinder portion (71) and the inner cylinder portion (72). It is located in an intricate place, and it is difficult to bring the polishing tool into contact in the polishing process after the coating material is applied. Also, the corner formed by the cylinder side end plate part (41) and the outer cylinder part (71) and the corner part formed by the cylinder side end plate part (41) and the inner cylinder part (72) are for polishing. In addition to the difficulty of contacting the tool, the coating material tends to accumulate. Even if the polishing tool can be brought into contact with the sliding contact portion, it is necessary to move the polishing tool along the outer cylinder portion (71) and the inner cylinder portion (72). Therefore, high positioning accuracy is required. On the other hand, among the piston side end plate portion (61), the sliding contact portion where the front end surface (75) of the outer cylinder portion (71) and the front end surface (76) of the inner cylinder portion (72) are in sliding contact is similarly polished. In addition to being located in an intricate place where it is difficult to make the tool for contact, the corners formed by the piston end plate (61) and the piston (60) and the piston end plate (61) and the bearing (62 ) And the coating material tends to accumulate at the corners formed by Even if the polishing tool can be brought into contact with the sliding contact portion, it is necessary to move the polishing tool along the piston (60) and the bearing portion (62). High positioning accuracy is required.

  That is, the tip end surfaces (66, 75, 76) of the piston (60), the outer cylinder portion (71), and the inner cylinder portion (72) of the cylinder side end plate portion (41) and the piston side end plate portion (61) are slid. In the case where a coating film is provided on the contact portion, workability is poor and the cost increases.

  On the other hand, the tip surface (66) of the piston (60) is not an intricate place in the integrally formed piston (60) and piston-side end plate part (61), but the outside is easy to contact the polishing tool. Located in the place where it appeared. Furthermore, the tip surface (66) of the piston (60) is not curved and is a flat surface, and therefore can be easily polished. In addition, the front end surfaces (75, 76) of the outer and inner cylinder portions (71, 72) are also integrally formed in the outer cylinder portion (71), the inner cylinder portion (72), and the cylinder side end plate portion (41). It is not located in an intricate position, but is located on the outside where the polishing tool is easily brought into contact. Furthermore, the front end surface (75) of the outer cylinder part (71) and the front end surface (76) of the inner cylinder part (72) are not only flat but also have the same height at both front end faces (75, 76). Therefore, it can polish easily.

  Further, the coating film (67, 78, 79) is formed on the piston side groove (66a) of the tip surface (66) of the piston (60) and the outer groove of the tip surface (75) of the outer cylinder part (71). (75a) and the inner cylinder groove (72) on the inner groove (76a) on the tip surface (76) reduces the man-hours required for coating film (67, 78, 79) and improves workability. Can be made.

  That is, as a configuration in which the coating film is provided on the front end surface (66, 75, 76), for example, in the case of the outer cylinder portion (71), as in Modification 2 shown in FIG. Apply the coating material to the tip surface (75) with the masking tape (80) attached to the inner peripheral surface of the cylinder part (71) to prevent the coating material from adhering to the peripheral surface. A method is conceivable. However, in this method, when a coating material is applied to the tip surface (75) of the outer cylinder portion (71), a slight amount of the coating material also adheres to the edge portion of the masking tape (80). Then, when the masking tape (80) is removed, the coating material adhering to the masking tape (80) remains as burrs (78a) on the inner peripheral side edge of the coating film (78). Therefore, after removing the masking tape (80), a step of removing the burr (78a) is required, and the number of steps increases.

  In contrast, in the first embodiment, the outer concave groove (75a) is formed in the tip surface (75) of the outer cylinder portion (71), and the coating material is applied in the outer concave groove (75a). The coating material applied in the outer groove (75a) is prevented from overflowing to the inner periphery and the outer peripheral edge of the tip surface (75) by the side wall of the outer groove (75a). That is, even if the coating material applied in the outer groove (75a) overflows from the outer groove (75a), as long as the coating material to be applied is an appropriate amount (the outer groove (75a)) Unless the coating material is applied in an excessive amount), it protrudes from the outer groove (75a) so as to rise in the normal direction of the tip surface (75). It is possible to prevent burrs from occurring in the part. As a result, the step of attaching the masking tape (80) and the step of removing burrs as described above can be eliminated, and the number of steps can be reduced and the workability can be improved.

  Here, the outer cylinder part (71) has been described, but the piston side groove (66a) and the inner cylinder part (66a) are respectively formed in the tip surface (66, 76) in the same manner in the piston (60) and the inner cylinder part (72). By providing the concave groove (76a), the number of steps for providing the coating film (67, 79) can be reduced and workability can be improved.

  Further, the coating film (67, 78, 79) is formed on the piston side groove (66a) of the tip surface (66) of the piston (60) and the outer groove of the tip surface (75) of the outer cylinder part (71). (75a) and the inner concave groove (76a) of the tip surface (76) of the inner cylinder part (72) can prevent the coating film (67, 78, 79) from peeling from the edge. .

  That is, as shown in FIG. 8, in the outer cylinder portion (71), the outer concave groove (75a) is not formed on the tip surface (75), and the coating film (78) is formed on the flat tip surface (75). ), There is a risk of peeling from the outer peripheral edge (78b) of the coating film (78) as shown at the outer peripheral edge of the tip surface (75) (in the figure, the outer periphery of the coating film (78) Although an example in which the peripheral edge portion (78b) peels is shown, there is a possibility that the inner peripheral side end portion also peels in the same manner.

  On the other hand, in the first embodiment, the outer groove (75a) is formed in the tip surface (75) of the outer cylinder part (71), and the coating film (78) is formed so as to fill the outer groove (75a). By providing this, the edge of the coating film (78) is bonded to the side wall of the outer concave groove (75a) and is covered with the side wall. In this way, the edge of the coating film (78) is bonded to the side wall of the outer concave groove (75a) and is covered with the side wall, thereby preventing the peeling from occurring at the edge. Furthermore, since the side wall of the outer concave groove (75a) is inclined, the edge of the coating film (78) becomes thinner as it approaches the edge, further preventing the peeling of the edge. can do.

  Here, the same applies to the piston (60) and the inner cylinder part (72) described for the outer cylinder part (71).

-Modification 1-
Next, Modification 1 of Embodiment 1 will be described. In this modification, the method of providing the coating film (78) on the tip surface (75) of the outer cylinder part (71) is changed.

  Specifically, as shown in FIG. 7, the tip surface (75) is formed with a stepped portion (75b) whose outer peripheral portion is recessed relative to the inner peripheral edge, and this stepped portion (75b ) Is provided so as to fill in). That is, the portion other than the inner peripheral edge of the tip surface (75) is a depressed step (75b), and the inner periphery of the step (75b) is formed by the inner peripheral edge of the tip (75). Side walls are formed on the side. The side wall is formed to be inclined so as to spread outward from the bottom wall toward the tip surface (75) of the outer cylinder portion (71). By doing so, the coating film (78) is formed thinly along the side wall as it approaches the inner peripheral edge, so that peeling of the edge can be reliably prevented.

  Further, the outer peripheral edge of the stepped portion (75b) is subjected to R processing. And the outer peripheral edge part of the coating film (78) is formed thinly along the R shape as it approaches the outer peripheral edge. In this way, by forming the outer peripheral edge of the coating film (78) thinner as it approaches the outer peripheral edge, peeling of the edge can be reliably prevented.

  Also, the outer cylinder part (71) has no cylinder chamber (C) formed on the outer peripheral side, so even if coating material adheres to the outer peripheral side surface of the outer cylinder part (71), the coating material is removed. There is no need to delete or remove burrs. That is, unlike the inner peripheral side where the cylinder chamber (C) is located on the outer peripheral side of the stepped portion (75b), it is less necessary to provide a side wall to suppress leakage of the coating material. Therefore, as described above, the stepped portion (75b) having no outer peripheral side wall is formed on the distal end surface (75), and the outer peripheral edge of the stepped portion (75b) is prevented from peeling off the coating film (78). Can be processed mainly (R processing is applied in this modification).

  Therefore, according to the first modification, the coating material provided on the tip surface (75) can be prevented from overflowing to the inner peripheral edge of the tip surface (75) of the outer cylinder portion (71), and the coating film ( 78) can be prevented from peeling off. In addition, the same effects as those of the first embodiment can be achieved.

-Modification 2-
Then, the modification 2 of Embodiment 1 is demonstrated. In this modification, the way of providing the coating film (67, 78, 79) on the tip surface (66, 75, 76) is changed. Here, a description will be given using the tip surface (75) of the outer cylinder part (71).

  Specifically, as shown in FIG. 8, the tip end surface (75) is not provided with the outer concave groove (75a) or the stepped portion (75b), and is coated on the flat tip end surface (75). A membrane (78) is provided. By doing so, as described above, the step of attaching the masking tape (80) and the step of removing burrs increase, and the end of the coating film (78) may be peeled off, but the tip surface ( The coating film (78) can be provided without forming the outer concave groove (75a) and the stepped portion (75b) in 75).

  As a result, the thrust loss of the compressor (1) can be reduced. In addition, since the coating film (78) is provided only on the tip surface (75) of the outer cylinder part (71), workability when forming the coating film (78) can be improved. Cost can be reduced. In addition, the same effects as those of the first embodiment can be achieved.

<< Embodiment 2 of the Invention >>
Next, Embodiment 2 of the present invention will be described.

  The compressor (201) according to the second embodiment is different from the first embodiment in that a cylinder, not a piston, rotates eccentrically. That is, the configuration of the compression mechanism (220) is different from the compression mechanism (20) according to the first embodiment. Therefore, the configuration of the compression mechanism (220) will be mainly described below. In addition, about the structure similar to Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 9, the compression mechanism (220) includes an upper housing (240), a lower housing (250), and a cylinder (270). In the compression mechanism (220), the cylinder (270) is accommodated in a space surrounded by the upper housing (240) and the lower housing (250).

  The upper housing (240) has a flat plate portion (241) and a peripheral wall portion (242).

  The flat plate portion (241) is formed in a disc shape and has an outer diameter substantially equal to the inner diameter of the casing (10). The flat plate portion (241) is fixed to the cylindrical portion (11) of the casing (10) by welding or the like. A bearing portion (243) that supports the main shaft portion (33a) of the drive shaft portion (33) is formed through the central portion of the flat plate portion (241). The main shaft portion (33a) is rotatably inserted into the bearing portion (243). An annular groove is formed on the surface of the flat plate portion (241) on the lower housing (250) side so as to surround the bearing portion (243), and a seal ring (255) is fitted in the groove. As in the first embodiment, the seal ring (255) is not provided concentrically with the bearing portion (243) (the rotation shaft (X) of the main shaft portion (33a) of the drive shaft portion (33)). Instead, it is eccentric with respect to the bearing portion (243) in the direction of the high pressure chamber (C1-Hp, C2-Hp) (see FIG. 10) at the end of the compression stroke described later.

  The peripheral wall portion (242) is formed in a cylindrical shape extending from the peripheral edge of the flat plate portion (241) to the lower housing (250) side. A suction port (244) that penetrates the peripheral wall portion (242) in the radial direction is formed in the peripheral wall portion (242), and a suction pipe (14) is inserted into the suction port (244).

  The lower housing (250) includes a piston side end plate portion (261) and a piston (260).

  The piston side end plate portion (261) is formed in a disc shape, and has an outer diameter slightly smaller than the inner diameter of the casing (10). The piston side end plate portion (261) is connected to the upper housing (240) with a bolt or the like. A bearing portion (262) that supports the main shaft portion (33a) of the drive shaft portion (33) is formed through the central portion of the piston side end plate portion (261). A main shaft portion (33a) is rotatably inserted into the bearing portion (262).

  The piston (260) has a cylindrical shape, and a base end portion thereof is integrally formed with the piston side end plate portion (261). The piston (260) is provided such that its axis coincides with the rotation axis (X) of the main shaft (33a) of the drive shaft (33) (that is, the axis of the bearing (262)). . The piston (260) has a through hole (265) formed at a position facing the suction port (244) of the upper housing (240) in the radial direction.

  The cylinder (270) has cylindrical outer and inner cylinder portions (271,272). The inner diameter of the outer cylinder part (271) is larger than the outer diameter of the piston (260), and the outer diameter of the inner cylinder part (272) is smaller than the inner diameter of the piston (260). The outer and inner cylinder parts (271, 272) are concentrically arranged, and the base end part is formed integrally with the cylinder side end plate part (277). The inner cylinder part (272) passes through the center part of the cylinder side end plate part (277) and also functions as a bearing part that is rotatably fitted to the eccentric part (33b) of the drive shaft part (33).

  As in the first embodiment, the piston (260) has a C-shape in which a part of the cylinder is divided by the dividing portion in plan view, and the swinging bush (264) is supported by the dividing portion. Has been. Further, in the cylinder (270), a cylinder chamber (C) is formed between the outer cylinder part (271) and the inner cylinder part (272), and the outer cylinder part (271) and the inner cylinder part (272). Is provided with a blade (273) extending across the cylinder chamber (C) (see FIG. 2).

  The cylinder (270) configured as described above includes the upper housing (240) and the lower housing (250) in a state in which the inner cylinder portion (272) is fitted to the eccentric portion (33b) of the drive shaft portion (33). The piston (260) is accommodated in a space surrounded by the cylinder chamber (C). At this time, the tip surface of the piston (260) (the surface facing the cylinder side end plate portion (277)) (266) is in sliding contact with the cylinder side end plate portion (277), while the front end surfaces of the inner and outer cylinder portions (271, 272). (The surface facing the piston side end plate portion (261)) (275, 276) is in sliding contact with the piston side end plate portion (261). As a result, the cylinder chamber (C) includes a cylinder side end plate part (277), a piston side end plate part (261), an outer cylinder part (271) and an outer cylinder part (271) surrounded by the piston (260), A side end plate portion (277), a piston side end plate portion (261), a piston (260), and an inner cylinder chamber (C2) surrounded by the inner cylinder portion (272) are partitioned.

  At this time, the blade (273) of the cylinder (270) is supported by the swing bush (264) of the piston (260). Thus, the cylinder (270) can freely advance and retreat along the inner surface of the swing bush (264) via the blade (273), and can swing freely around the dividing portion via the swing bush (264). It is configured to be able to move. That is, the cylinder (270) is engaged with the swing bush (264), and the swing bush (264) constitutes a support portion.

  The outer cylinder chamber (C1) and the inner cylinder chamber (C2) are respectively divided into a high pressure chamber (C1-Hp, C2-Hp) and a low pressure chamber (C1-Lp, C2) by a blade (273) of the cylinder (270). -Lp) (see FIG. 2).

  In the state where the cylinder (270) is accommodated in the space surrounded by the upper housing (240) and the lower housing (250), the outer peripheral surface of the outer cylinder part (271), the upper housing (240), and the lower housing ( There is a space between them. This space communicates with the suction pipe (14) via the suction port (244) to form a suction space (256).

  A suction port (274) is formed through the portion of the outer cylinder portion (271) facing the suction port (244). That is, the refrigerant flowing into the suction space (256) from the suction pipe (14) via the suction port (244) passes through the suction port (274) of the outer cylinder part (271) to the outer cylinder chamber (C1). Flows into the low pressure chamber (C1-Lp). The refrigerant flowing into the low pressure chamber (C1-Lp) also flows into the low pressure chamber (C2-Lp) of the inner cylinder chamber (C2) through the through hole (265) of the piston (260).

  On the other hand, as shown in FIG. 10, an outer discharge port (251) and an inner discharge port (252) for discharging the compressed refrigerant are formed in the piston side end plate portion (261). The outer discharge port (251) opens to the high pressure chamber (C1-Hp) of the outer cylinder chamber (C1) near the blade (273), and the inner discharge port (252) closes to the inner cylinder chamber ( It is formed through the piston end plate (261) so as to open to the high pressure chamber (C2-Hp) of C2). Reed valves (not shown) are provided at the downstream ends of the outer and inner discharge ports (251,252) as discharge valves for opening and closing the outer and inner discharge ports (251,252).

  A muffler (253) is attached to the lower side of the lower housing (250). The muffler (253) is provided so as to cover the lower housing (250) from below, and forms a discharge space (254) between the muffler (253) and the lower housing (250). A lower communication passage (268) that opens to the discharge space (254) is formed through the piston side end plate portion (261) of the lower housing (250). An upper communication path (245) that communicates with the lower communication path (268) and opens to the high-pressure space (19) is formed through the peripheral wall (242) of the upper housing (240). The refrigerant discharged from the outer and inner discharge ports (251, 252) is once discharged into the discharge space (254), and the high-pressure space (19 in the casing (10) through the lower and upper communication passages (268, 245). ) Flows out. That is, the muffler (253) has a silencing function for the discharge gas discharged from the compression mechanism (220).

  In a state where the cylinder (270) is accommodated in a space surrounded by the upper housing (240) and the lower housing (250), the seal ring (255) is disposed on the back side of the cylinder side end plate portion (277). Are in contact. With this seal ring (255), the space between the flat plate portion (241) of the upper housing (240) and the cylinder side end plate portion (277) is separated from the inner gap (257) inside the seal ring (255), It is divided into an outer gap (258) outside the seal ring (255).

  Since the inner clearance (257) is filled with high-pressure lubricating oil supplied through the oil supply passage of the drive shaft (33), the inner pressure of the inner clearance (257) is reduced by the refrigerant discharged from the compression mechanism (220). It is almost the same as the pressure (discharge pressure). Further, since the outer gap (258) communicates with the suction space (256), the inner pressure of the outer gap (258) is substantially the same as the pressure of the refrigerant sucked into the compression mechanism (220) (suction pressure). . The seal ring (255) has a function of applying a pressing force to the cylinder (270) in addition to a function of partitioning the inner gap (257) and the outer gap (258). That is, the cylinder (270) is pressed toward the piston (260) by the internal pressure of the inner gap (257) and the outer gap (258) and the pressing force of the seal ring (255).

  Thus, in the configuration in which the piston (260) is pressed against the cylinder (270), a thrust force (axial force) acts on the sliding contact portion between the piston (260) and the cylinder (270). Therefore, the sliding contact surfaces of the piston (260) and the cylinder (270) are coated to reduce the thrust loss.

  Specifically, a piston-side groove (266a) is formed on the tip surface (266) of the piston (260) that is in sliding contact with the cylinder-side end plate portion (277), and the piston-side groove (266a) is formed in the piston-side groove (266a). A coating film (267) is provided so as to fill. On the other hand, the front end surface (275) of the outer cylinder portion (271) and the front end surface (276) of the inner cylinder portion (272) that are in sliding contact with the piston side end plate portion (261) are respectively provided with an outer concave groove (275a) and an inner side Concave grooves (276a) are formed, and coating films (278, 279) are provided on the outer and inner concave grooves (275a, 276a). These coating films (267, 278, 279) constitute a lubricating film.

  These piston side concave groove (266a), outer concave groove (275a) and inner concave groove (276a) have pistons (260), outer cylinder part (271) and inner cylinder part (272) on both side walls from the bottom wall, respectively. Inclined so as to spread outward (that is, so as to widen the groove width) toward the front end surface (266, 275, 276) of the film. In FIG. 9, the piston side concave groove (266a), the outer concave groove (275a), and the inner concave groove (276a) are drawn with exaggerated depths. The actual depth of the concave grooves (266a, 275a, 276a) is several tens of μm.

  Similar to the first embodiment, the piston-side concave groove (266a) has a C-shaped piston (260) on the front end surface (266) of the piston (260) in a plan view, and a plan view C along the circumferential direction of the piston (260). It is formed in a letter shape. Further, the outer and inner concave grooves (275a, 276a) are formed over the entire circumference on the front end surface (275) of the outer cylinder portion (271) and the front end surface (276) of the inner cylinder portion (272), respectively. And formed in an annular shape in plan view.

  Coating films (267, 278, 279) are formed in the piston-side groove (266a), the outer groove (275a), and the inner groove (276a). Specifically, the coating material is coated in the piston side groove (266a). At this time, the coating material is applied in the piston-side concave groove (266a) to the extent that it protrudes from the tip surface (266) of the piston (260). Then, by polishing the portion of the coating material that protrudes from the tip surface (266) of the piston (260), the coating film (267) is formed substantially flush with the tip surface (266) of the piston (260). . In addition, as a coating material, the material which can improve the slidability of the front end surface (266) of a piston (260) is used. That is, in the state after polishing, a material having a lower coefficient of friction than the portion of the tip surface (266) of the piston (260) other than the coating film (267) (the portion formed of the material of the piston (260) body). Can be adopted. For example, fluororesin, DLC (Diamond like Carbon), ceramic, or the like can be used as the coating material.

  The coating films (278, 279) are also formed in the outer concave groove (275a) and the inner concave groove (276a).

  These coating films (267, 278, 279) are in sliding contact with the cylinder side end plate portion (277) and the piston side end plate portion (261).

-Driving action-
Next, the operation of the compressor (201) will be described.

  When the electric motor (30) is driven, the rotation of the rotor (32) is transmitted to the cylinder (270) of the compression mechanism (220) via the drive shaft portion (33). Then, the blade (273) moves back and forth (reciprocating motion) along the swing bush (264), and the cylinder (270) swings with respect to the swing bush (264). At that time, the rocking bush (264) substantially makes surface contact with the piston (260) and the blade (273). The cylinder (270) rotates eccentrically with respect to the drive shaft (33) while swinging with respect to the piston (260), and the compression mechanism (220) performs a predetermined compression operation.

  In plan view, the eccentric rotation angle of the cylinder (270) is a straight line extending in the radial direction from the rotation axis (X) of the drive shaft (33) and passing through the swing center of the swing bush (264) in plan view. The axis of the cylinder (270) (the axis of the eccentric part (33b)) is located at the center of the cylinder (ie, the axis of the cylinder (270) on the line connecting the rotating shaft (X) and the swing bush (264)). The eccentric rotation angle at the point of time is 0 °. (A) shows the state where the eccentric rotation angle of the cylinder (270) is 0 ° or 360 °, (B) shows the state where the eccentric rotation angle of the cylinder (270) is 90 °, and (C) shows the state of the cylinder ( 270) shows a state where the eccentric rotation angle is 180 °, and FIG. 4D shows a state where the eccentric rotation angle of the cylinder (270) is 270 °.

  Specifically, in the outer cylinder chamber (C1), the volume of the low-pressure chamber (C1-Lp) is almost the minimum in the state of FIG. 10 (D), from which the drive shaft (33) rotates clockwise in the figure. Then, when the volume of the low pressure chamber (C1-Lp) increases with the change to the state of FIG. 10 (A) to FIG. 4 (C), the refrigerant flows into the suction pipe (14) and the suction port ( 274) and is sucked into the low pressure chamber (C1-Lp).

  When the drive shaft portion (33) makes one revolution and enters the state of FIG. 10 (D) again, the suction of the refrigerant into the low pressure chamber (C1-Lp) is completed. This low-pressure chamber (C1-Lp) is now a high-pressure chamber (C1-Hp) in which the refrigerant is compressed, and a new low-pressure chamber (C1-Lp) is formed across the blade (273). When the drive shaft portion (33) further rotates, the suction of the refrigerant is repeated in the low pressure chamber (C1-Lp), while the volume of the high pressure chamber (C1-Hp) decreases, and the high pressure chamber (C1-Hp) The refrigerant is compressed. When the pressure in the high-pressure chamber (C1-Hp) reaches a predetermined value and the differential pressure from the discharge space (254) reaches a set value, the discharge valve is opened by the high-pressure refrigerant in the high-pressure chamber (C1-Hp), and the high-pressure refrigerant Is discharged into the discharge space (254) and flows out from the muffler (253) to the high-pressure space (19) in the casing (10).

  In the inner cylinder chamber (C2), the volume of the low-pressure chamber (C2-Lp) is almost the minimum in the state of FIG. 10B, and from here the drive shaft portion (33) rotates clockwise in FIG. When the volume of the low pressure chamber (C2-Lp) increases as the state changes from (C) to FIG. 10 (A), the refrigerant flows into the suction pipe (14), the suction space (256), and the suction. The air is sucked into the low pressure chamber (C2-Lp) of the inner cylinder chamber (C2) through the port (274) and the through hole (265).

  When the drive shaft portion (33) makes one revolution and again enters the state of FIG. 10 (B), the suction of the refrigerant into the low pressure chamber (C2-Lp) is completed. The low-pressure chamber (C2-Lp) is now a high-pressure chamber (C2-Hp) in which the refrigerant is compressed, and a new low-pressure chamber (C2-Lp) is formed across the blade (273). When the drive shaft (33) further rotates, the suction of the refrigerant is repeated in the low pressure chamber (C2-Lp), while the volume of the high pressure chamber (C2-Hp) decreases, and the high pressure chamber (C2-Hp) The refrigerant is compressed. When the pressure in the high pressure chamber (C2-Hp) reaches a preset value and the differential pressure from the discharge space (254) reaches a set value, the discharge valve is opened by the high pressure refrigerant in the high pressure chamber (C2-Hp), and the high pressure refrigerant Is discharged into the discharge space (254) and flows out from the muffler (253) to the high-pressure space (19) in the casing (10).

  The high-pressure refrigerant compressed in the outer cylinder chamber (C1) and the inner cylinder chamber (C2) and flowing into the high-pressure space (19) in the casing (10) is discharged from the discharge pipe (15) and is condensed in the refrigerant circuit. After passing through the expansion stroke and the evaporation stroke, it is sucked into the compressor (201) again.

  Thus, when the piston (260) compresses the refrigerant while rotating eccentrically with respect to the cylinder (270), the piston (260) includes the seal ring (255), the inner gap (257), and the outer gap (258). The pressing force to the cylinder (270) side is applied by the internal pressure. On the other hand, a separation force acts on the piston (260) in a direction away from the cylinder (270) by the internal pressure of the cylinder chamber (C). And in order to ensure the airtightness of the cylinder chamber (C), the pressing force is set to be larger than the separation force, and the difference between the pressing force and the separation force is used as a thrust force as a piston ( 260) and the cylinder (270), in detail, between the tip surface (266) of the piston (260) and the cylinder side end plate portion (277), the tip surface (275) of the outer cylinder portion (271) Between the front end surface (276) of the inner cylinder part (272) and the piston side end plate part (261). With this thrust force acting, the piston (260) and the cylinder (270) slide relative to each other and rotate eccentrically, so the tip surface (266) of the piston (260) and the cylinder end plate (277) And between the front end face (275,276) of the outer and inner cylinder parts (271,272) and the piston side end plate part (261).

  In the compression mechanism (220) according to the second embodiment, against the thrust force described above, the tip surface (266) of the piston (260), the tip surface (275) of the outer cylinder portion (271), and the inner cylinder portion ( 272) is provided with the coating film (267, 78, 279) on the tip surface (276), respectively. By doing so, the friction coefficient of the tip surfaces (266, 275, 276) can be reduced, so that the thrust loss can be reduced.

-Effect of Embodiment 2-
Therefore, according to the second embodiment, the tip surface (266) of the piston (260), the tip surface (275) of the outer cylinder portion (271), and the tip surface (276) of the inner cylinder portion (272), respectively. By providing the coating film (267, 278, 279), the thrust loss of the compressor (201) can be reduced.

  Further, since the coating film (267,278,279) is provided only on the tip surface (266,278,279) of the piston (260), the outer cylinder part (271) and the inner cylinder part (272), the coating film (267,278,279) is formed. The workability can be improved, and the cost can be reduced.

  Further, the coating film (267, 278, 279) is formed on the piston side groove (266a) of the tip surface (266) of the piston (260), the outer groove (275a) of the tip surface (275) of the outer cylinder part (271), and By providing it in the inner concave groove (276a) of the tip surface (276) of the inner cylinder part (272), it is possible to reduce the number of steps for providing the coating film (267, 278, 279) and improve workability. In addition, the same effects as those of the first embodiment can be achieved.

  The coating film (267, 278, 279) is any one of the tip surface (266) of the piston (260), the tip surface (275) of the outer cylinder portion (271), and the tip surface (276) of the inner cylinder portion (272). It suffices if one is provided. Thrust loss can be reduced by providing the coating film (267,278,279) on any one of the tip surfaces (266,278,279). However, as the radially outer portion increases, the portion away from the oscillation center increases and the thrust loss increases, and the increase in thrust loss due to the eccentric action of the separating force is the radially outer portion. Therefore, it is preferable to provide the coating film (278) at least on the front end surface (275) of the outer cylinder part (271) located at the outermost radial direction. That is, of the tip surface (266) of the piston (260), the tip surface (275) of the outer cylinder portion (271) and the tip surface (276) of the inner cylinder portion (272), the tip surface of the outer cylinder portion (271) Providing the coating film (278) on (275) can most effectively reduce the thrust loss.

<< Embodiment 3 of the Invention >>
Next, a third embodiment of the present invention will be described.

  The compressor (301) according to the third embodiment is a scroll compressor in which a fluid chamber is formed by a fixed scroll and a movable scroll, and the compression according to the first and second embodiments in which a fluid chamber is formed by a cylinder and a piston. Different from the machine. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 1, the scroll compressor (301) includes a casing (10) formed of a closed dome type pressure vessel. Inside the casing (10), a compression mechanism (320) for compressing the refrigerant gas, an electric motor (30) for driving the compression mechanism (320), and a lower bearing (335) are accommodated in the upward direction. Yes. The compression mechanism (320) and the electric motor (30) are connected by a drive shaft portion (33) extending in the vertical direction.

  The casing (10) includes a suction pipe (14) that guides the refrigerant in the refrigerant circuit to the compression mechanism (320), and a discharge pipe (15) that discharges the refrigerant in the casing (10) to the outside of the casing (10). It is joined. The suction pipe (14) opens into a compression chamber (C) described later of the compression mechanism (320). On the other hand, the discharge pipe (15) opens into the high-pressure space (19) in the casing (10).

  The drive shaft portion (33) includes a main shaft portion (33a) and an eccentric portion (33b), and the main shaft portion (33a) is rotatably supported by the lower bearing (335) and a housing (317) described later. ing. The eccentric part (33b) is formed at the upper end of the drive shaft part (33). The eccentric portion (33b) is eccentric by a predetermined amount from the axis (rotating shaft (X)) of the drive shaft portion (33). On the other hand, at the lower end of the drive shaft portion (33), an oil supply pump (34) for pumping refrigeration oil accumulated at the bottom of the casing (10) is provided. The oil supply pump (34) supplies the refrigerating machine oil to each sliding portion of the compression mechanism (320) through an oil supply passage (35) formed through the drive shaft portion (33) in the vertical direction.

  The compression mechanism (320) includes a fixed scroll (360), a movable scroll (370), and a housing (317). In this compression mechanism (320), the fixed side wrap (363) of the fixed scroll (360) and the movable side wrap (372) of the movable scroll (370) are engaged with each other, so that the compression chamber (C ) Is formed. The fixed scroll (360) constitutes a fixed member, and the movable scroll (370) constitutes a movable member.

  The fixed scroll (360) includes a fixed side end plate portion (361), an outer peripheral cylindrical portion (362), and a fixed side wrap (363), and is fixed to the upper end plate portion (12) of the casing (10). .

  The fixed side end plate portion (361) is formed in a disc shape, and a suction port (not shown) is formed through the center portion thereof.

  The outer peripheral cylindrical portion (362) is formed in a cylindrical shape extending downward (movable scroll (370) side) from the peripheral portion of the fixed-side end plate portion (361).

  The fixed-side wrap (363) is erected and fixed on the lower surface (surface facing the movable scroll (370)) side of the fixed-side end plate portion (361) in the space surrounded by the outer peripheral cylindrical portion (362). It is formed integrally with the side end plate portion (361). The fixed side wrap (363) is formed in a spiral wall shape having a constant height.

  The movable scroll (370) includes a movable side end plate portion (371), a movable side wrap (372), and a protruding cylinder portion (373).

  The movable side end plate portion (371) is formed in a disc shape. In the movable side end plate portion (371), the movable side wrap (372) is erected on the upper surface (the surface facing the fixed scroll (360)), and the protruding cylinder is formed on the lower surface (the surface facing the housing (317)). Part (373) is erected.

  The movable side wrap (372) is formed integrally with the movable side end plate portion (371). The movable wrap (372) is formed in a spiral wall shape having a constant height.

  The protruding cylinder part (373) is formed in a cylindrical shape, and is arranged at substantially the center of the back surface of the movable side end plate part (371). The eccentric part (33b) of the drive shaft part (33) is rotatably fitted in the protruding cylinder part (373). That is, the eccentric part (33b) of the drive shaft part (33) is engaged with the movable scroll (370). When the drive shaft portion (33) rotates, the movable scroll (370) engaged with the eccentric portion (33b) rotates eccentrically about the rotation shaft (X). At this time, the rotation radius of the movable scroll (370) matches the distance between the shaft center of the eccentric part (33b) and the rotation shaft (X) of the drive shaft part (33), that is, the eccentric amount of the eccentric part (33b). .

  The housing (317) is fixed to the cylindrical portion (11) of the casing (10). The housing (317) includes an upper stage part (317a), a middle stage part (317b), and a lower stage part (317c). The upper stage part (317a) is formed in a dish shape. The middle step (317b) is formed in a cylindrical shape having a smaller diameter than the upper step (317a), and projects downward from the lower surface of the upper step (317a). The lower step portion (317c) is formed in a cylindrical shape having a smaller diameter than the middle step portion (317b), and protrudes downward from the lower surface of the middle step portion (317b). An Oldham ring (318), which is a rotation prevention mechanism, is provided on the upper stage (317a). In addition, an annular seal member (355) is disposed in the middle step (317b) so as to be in close contact with the inner peripheral surface thereof. Further, the main shaft portion (33a) of the drive shaft portion (33) is inserted into the lower step portion (317c), and the lower step portion (317c) serves as a sliding bearing that supports the drive shaft portion (33). Yes. Further, the eccentric portion (33b) of the drive shaft portion (33) is located inside the middle step portion (317b).

  In the compression mechanism (320) configured as described above, the movable scroll (370) is housed in a space surrounded by the fixed scroll (360) and the housing (317). At this time, the movable side wrap (472) and the fixed side wrap (363) are meshed with each other to form a plurality of compression chambers (C). The movable scroll (370) is placed on the upper stage (317a) of the housing (317) via the Oldham ring (318). At this time, the lower surface of the movable side end plate portion (371) of the movable scroll (370) is in contact with the seal member (355). As a result, the space defined by the movable scroll (370) and the housing (317) is divided into a high pressure space (357) inside the seal member (355) and a low pressure space (358) outside the seal member (355). It is divided into and.

  The high-pressure space (357) is a high-pressure lubricant supplied to the eccentric part (33b) and the protruding cylinder part (373) of the drive shaft part (33) through the oil supply passage (35) of the drive shaft part (33). Therefore, the internal pressure of the high-pressure space (357) is almost the same as the pressure (discharge pressure) of the refrigerant discharged from the compression mechanism (320). The seal member (355) has a function of applying a pressing force to the movable scroll (370) in addition to a function of partitioning the high pressure space (357) and the low pressure space (358). That is, the movable scroll (370) is pressed toward the fixed scroll (360) by the internal pressure of the high pressure space (357) and the low pressure space (358) and the pressing force of the seal member (355).

  Thus, in the configuration in which the movable scroll (370) is pressed against the fixed scroll (360), thrust force (axial force) acts on the sliding contact portion between the movable scroll (370) and the fixed scroll (360). . Thus, the sliding contact surfaces of the movable scroll (370) and the fixed scroll (360) are coated to reduce the thrust loss.

  Specifically, as shown in FIG. 12, the movable side concave groove (375a) is formed on the distal end surface (375) of the movable side wrap (372) of the movable scroll (370) that is in sliding contact with the fixed side end plate part (361). Is formed, and a coating film (378) is provided in the movable groove (375a). On the other hand, a fixed-side concave groove (366a) is formed in the distal end surface (366) of the fixed-side wrap (363) of the fixed scroll (360) that is in sliding contact with the movable side end plate portion (371). A coating film (367) is provided in the concave groove (366a). The distal end surface (368) of the outer peripheral cylindrical portion (362) of the fixed scroll (360) that is in sliding contact with the radially outer portion of the movable side wrap (372) in the movable side end plate portion (371) is recessed on the outer peripheral side. A groove (368a) is formed, and a coating film (369) is provided in the outer circumferential groove (368a). These coating films (367, 369, 378) constitute a lubricating film.

  These fixed-side concave groove (366a), outer peripheral-side concave groove (368a), and movable-side concave groove (375a) each have both side walls extending from the bottom wall to the distal end surface (366) of the fixed-side wrap (363) and the outer peripheral cylindrical portion. (362) and the distal end surface (375) of the movable side wrap (372) are inclined toward the distal end surface (368) and the distal end surface (375) of the movable side wrap (372). In FIG. 13, the fixed side groove (366a), the outer side groove (368a), and the movable side groove (375a) are drawn with exaggerated depths. The actual depth of the concave grooves (366a, 368a, 375a) is several tens of μm.

  Coating films (367, 369, 375) are formed in the fixed side groove (366a), the outer side groove (368a), and the movable side groove (375a) thus configured. Specifically, the coating material is coated so as to fill the fixed side ditch (366a) in the fixed side ditch (366a). At this time, the coating material is applied in the fixed side groove (366a) to the extent that it protrudes from the front end surface (366) of the fixed scroll (360). Then, by polishing the portion of the coating material that protrudes from the tip surface (366) of the fixed scroll (360), the coating film (367) is formed substantially flush with the tip surface (366) of the fixed scroll (360). Is done. In addition, as a coating material, the material which can improve the slidability of the front end surface (366) of a fixed scroll (360) is used. That is, in the state after polishing, the friction coefficient is lower than that of the tip surface (366) of the fixed scroll (360) other than the coating film (367) (the portion formed of the material of the fixed scroll (360) main body). Material can be adopted. For example, fluororesin, DLC (Diamond like Carbon), ceramic, or the like can be used as the coating material.

  The coating films (369, 378) are similarly formed in the outer circumferential groove (368a) and the movable groove (375a).

  In the scroll compressor (301) according to the third embodiment, the driving force generated by the electric motor (30) is transmitted to the movable scroll (370) via the driving shaft portion (33). In the compression mechanism (320), the volume of the compression chamber (C) changes with the eccentric rotation of the movable scroll (370). As a result, the refrigerant gas sucked into the compression chamber (C) through the suction pipe (14) is compressed. The compressed refrigerant gas flows into the high-pressure space (19) through the discharge passage (not shown), and then is sent out of the casing (10) through the discharge pipe (15).

  Thus, when the movable scroll (370) compresses the refrigerant while rotating eccentrically with respect to the fixed scroll (360), the movable scroll (370) includes the seal member (355), the high pressure space (357), and the low pressure space. The pressing force to the fixed scroll (360) side acts by the internal pressure of (358). On the other hand, a separation force acts on the movable scroll (370) in a direction away from the fixed scroll (360) by the internal pressure of the compression chamber (C). In order to ensure the airtightness of the compression chamber (C), the pressing force is set to be larger than the separation force, and the difference between the pressing force and the separation force is used as a thrust force to move the movable scroll. (370) and the fixed scroll (360) sliding contact portion, specifically, between the front end surface (375) of the movable scroll (370) and the fixed side end plate portion (361), and the front end surface of the fixed scroll (360) (366) and the distal end surface (368) of the outer peripheral cylindrical portion (362) and the movable end plate portion (371). Under this thrust force, the movable scroll (370) and the fixed scroll (360) slide relative to each other and rotate eccentrically, so that the tip surface (375) of the movable scroll (370) and the fixed end plate portion (361) and between the front end surface (366) of the fixed scroll (360) and the front end surface (368) of the outer peripheral cylindrical portion (362) and the movable side end plate portion (371), thrust loss occurs. Yes.

  With respect to the thrust force described above, in the compression mechanism (320) according to the third embodiment, the front end surface (366) of the fixed side wrap (363) of the fixed scroll (360) and the front end surface of the outer peripheral cylindrical portion (362) (368) and the coating film (367, 369, 378) are provided on the tip surface (375) of the movable side wrap (372) of the movable scroll (370), respectively. By doing so, the friction coefficient of the tip surface (366, 368, 375) can be reduced, so that the thrust loss can be reduced.

-Effect of Embodiment 3-
Therefore, according to the third embodiment, the front end surface (366) of the fixed side wrap (363) of the fixed scroll (360), the front end surface (368) of the outer peripheral cylindrical portion (362), and the movable side of the movable scroll (370). By providing the coating film (367, 369, 375) on the tip surface (375) of the wrap (372), the thrust loss of the scroll compressor (301) can be reduced.

  In addition, the same effects as those of the first embodiment can be achieved.

<< Other Embodiments >>
About the said embodiment, it is good also as following structures.

  That is, in the first and second embodiments, the compressor in which the outer cylinder chamber and the inner cylinder chamber are defined by accommodating the annular piston in the annular cylinder chamber in plan view is employed. It is not limited to. For example, a so-called swing type compressor may be used in which a circular piston is accommodated in a circular cylinder chamber so that an annular cylinder chamber is defined only on the outside of the piston. Any configuration can be adopted as long as the compressor rotates eccentrically.

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

  As described above, the present invention is useful for a rotary fluid machine that rotates relatively eccentrically while the fixed member and the movable member receive a thrust force.

It is a longitudinal section of the compressor concerning Embodiment 1 of the present invention. It is sectional drawing in the II-II line of FIG. It is a longitudinal cross-sectional view which shows the structure of the compression mechanism of a compressor. It is an operation state figure of a compression mechanism. It is a reference figure which shows the locus | trajectory of each part of the piston which rotates eccentrically without rocking | fluctuating. It is explanatory drawing which shows the locus | trajectory of each part of the piston which rotates eccentrically while rocking | fluctuating. 10 is an enlarged partial cross-sectional view showing an outer cylinder portion according to Modification 1. FIG. 10 is an enlarged partial cross-sectional view showing an outer cylinder portion according to Modification 2. FIG. It is a longitudinal cross-sectional view which shows the structure of the compression mechanism of the compressor which concerns on Embodiment 2. FIG. It is an operation state figure of a compression mechanism. It is a longitudinal cross-sectional view of the compressor which concerns on Embodiment 3. FIG. It is an enlarged view of a fixed scroll and a movable scroll.

Explanation of symbols

41 Cylinder side end plate (fixed side end plate)
60 Piston (movable member)
61 Piston side end plate (movable side end plate)
64 Swing bush (support)
66 Tip surface
66a Piston groove (groove)
67 Coating film (lubricating film)
70 Cylinder (fixing member)
75,76 Tip surface
75a Outer groove (concave groove)
76a Inner groove (concave groove)
78,79 Coating film (lubricant film)
260 Piston (fixed member)
261 Piston side end plate (fixed side end plate)
264 Swing bush (support)
266 Tip surface
266a Piston groove (groove)
267 Coating film (lubricating film)
270 cylinder (movable member)
275,276 Tip surface
275a Outer groove (groove)
276a Inner groove (concave groove)
278,279 Coating film (lubricating film)
360 Fixed scroll (fixed member)
361 Fixed end panel (fixed side panel)
366 Tip surface
366a Groove on the fixed side
368a Groove on outer side
367,369 Coating film (lubricating film)
370 Movable scroll (movable member)
375 Tip surface
375a Groove on movable side
378 Coating film (lubricant film)
C Cylinder chamber (fluid chamber)
C1 Outer cylinder chamber (fluid chamber)
C2 Inner cylinder chamber (fluid chamber)
C1-Hp, C2-Hp High pressure chamber (fluid chamber)
C1-Lp, C2-Lp Low pressure chamber (fluid chamber)

Claims (8)

A rotary type in which the movable member (60) rotates eccentrically with respect to the fixed member (70) and changes the volume of the fluid chamber (C) formed between the fixed member (70) and the movable member (60). A fluid machine,
On the base end side of the fixed member (70), a fixed-side end plate portion (41) that slidably contacts the distal end surface (66) of the movable member (60) and divides the fluid chamber (C) is integrally provided. And
On the proximal end side of the movable member (60), a movable side end plate portion (61) that slidably contacts the distal end surface (75, 76) of the fixed member (70) to partition the fluid chamber (C) is integrally formed. Provided in
At least one of the fixed member (70) and the movable member (60) is provided with a lubricating coating (67, 78, 79) for reducing friction only on the tip surface (66, 75, 76). A rotary fluid machine characterized by comprising: In claim 1,
The movable member (60) engages with a support portion (64) provided at a position away from the center of eccentric rotation, and rotates eccentrically while swinging about the support portion (64). It is comprised in the rotary fluid machine characterized by the above-mentioned. In claim 2,
The fixing member has an outer cylinder part (71) and an inner cylinder part (72), and an annular fluid chamber (C) is formed between the outer cylinder part (71) and the inner cylinder part (72). Cylinder (70)
The movable member is housed in the fluid chamber (C) in an eccentric state with respect to the cylinder (70), and divides the fluid chamber (C) into an outer fluid chamber (C1) and an inner fluid chamber (C2). An annular piston (60)
The lubricating coating (67, 78, 79) is provided on at least one tip surface (66, 75, 76) of the outer cylinder part (71), the inner cylinder part (72) and the piston (60). A rotary fluid machine characterized by comprising: In claim 3,
The rotary fluid machine is characterized in that the lubricating coating (78) is provided at least on a tip surface (75) of the outer cylinder part (71). In claim 4,
The lubricating fluid (66, 79) is further provided on the front end surface (66) of the piston (60) and the front end surface (76) of the inner cylinder part (72). machine. In any one of claims 1 to 5,
Tip surfaces (66, 75, 76) on which the lubricating coating (67, 78, 79) is provided on the tip surfaces (75, 76) of the fixed member (70) and the tip surfaces (66) of the movable member (60). ) Has recessed grooves (66a, 75a, 76a)
The rotary fluid machine, wherein the lubricating coating (67, 78, 79) is provided so as to fill the concave grooves (66a, 75a, 76a). In claim 4,
On the tip surface (75) of the outer cylinder portion (71), a stepped portion (75b) is formed in which a portion on the outer peripheral side is recessed relative to the inner peripheral edge portion,
The rotary fluid machine, wherein the lubricating coating (78) is provided so as to fill the stepped portion (75b). In any one of Claims 1 thru | or 7,
A rotary fluid machine that is connected to a refrigerant circuit that performs a refrigeration cycle, and compresses or expands carbon dioxide filled in the refrigerant circuit as a refrigerant.

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