JP5429353B1 - Compressor - Google Patents

Abstract

To improve the efficiency of a compressor by appropriately setting a lift amount of a valve body of a discharge valve.
The area of the inflow end (51) of the discharge port (50) is Ai, the peripheral length of the inflow end (51) is Li, and the hydraulic diameter of the inflow end (51) is Di = 4 (Ai / Li). And Further, the peripheral length of the outflow end (52) of the discharge port (50) is Lo, the reference lift amount of the valve body (61) is ho, the outflow end (52) of the discharge port (50) and the valve body (61) The cross-sectional area of the outflow side passage (70) formed between the two is Ao = Lo × ho, and the hydraulic diameter of the outflow side passage (70) is Do = 4 (Ao / 2Lo). Then, the ratio (Do / Di) of the hydraulic diameter Do of the outflow side channel (70) to the hydraulic diameter Di of the inflow end (51) of the discharge port (50) is set to 0.5 or less.
[Selection] Figure 5

Description

  The present invention relates to a compressor provided with a discharge valve.

  Conventionally, a compressor provided with a discharge valve for opening and closing a discharge port is known. For example, Patent Document 1 discloses a rotary compressor including a so-called reed valve as a discharge valve. Also, Patent Document 2 discloses a discharge valve similar to Patent Document 1.

  In the rotary compressor of Patent Document 1, a discharge valve is provided in the main bearing. The discharge valve includes a plate-like valve body provided so as to cover the outflow end of the discharge port. In a state where the internal pressure of the compression chamber is lower than the back pressure of the valve body, the valve body blocks the discharge port to prevent the back flow of fluid to the compression chamber. On the other hand, when the internal pressure of the compression chamber becomes higher than the back pressure of the valve body, the valve body is elastically deformed and separated from the outflow end of the discharge port. For this reason, the high-pressure fluid in the compression chamber flows out through the clearance between the outlet end of the discharge port and the valve body.

JP 2008-101503 A Japanese Patent Laid-Open No. 2002-070768

  Here, in order to improve the efficiency of the compressor, it is desirable to suppress the pressure loss when the fluid flows out from the discharge port as low as possible. In the past, “in order to reduce the pressure loss when the fluid flows out from the discharge port, it is desirable to increase the distance between the valve body in the floated state and the outflow end of the discharge port as much as possible. It has been thought that the lift amount of the valve disc must be as large as possible.

  In contrast, when the lift amount of the valve body of the discharge valve exceeds a certain level, the inventors of the present invention have little pressure loss when the fluid flows out from the discharge port even if the lift amount is further increased. It was found that it did not decrease. The reason will be explained. As will be described in detail later, the larger the lift amount of the valve body of the discharge valve, the larger the vortex generated around the outflow end of the discharge port. This vortex prevents the flow of fluid passing through the gap between the outlet end of the discharge port and the valve body. For this reason, if the lift amount of the valve body of the discharge valve exceeds a certain level, even if the lift amount of the valve body is increased further, the influence of the vortex increases, so the pressure loss when the fluid flows out from the discharge port Almost no decrease.

  This invention is made | formed in view of this point, The objective is to set the lift amount of the valve body of a discharge valve appropriately, and to improve the efficiency of a compressor.

The first invention includes a fixed side member (45) that forms a compression chamber (36), and a movable side member (38) that is driven to rotate and changes the volume of the compression chamber (36), and the fluid is The compressor is designed to be sucked into the compression chamber (36) and compressed. The fixed side member (45) is formed with a discharge port (50) that passes through the fixed side member (45) and guides fluid from the compression chamber (36), and the discharge port (50 ) Is provided, and the discharge valve (60) closes the discharge port (50) by covering the outflow end (52) of the discharge port (50). 50) is provided with a valve body (61) which opens the discharge port (50) by floating from the outflow end (52) of the discharge port (50), and the area of the inflow end (51) of the discharge port (50) is Ai. 51) The peripheral length of Li is the hydraulic diameter of the inflow end (51) is Di = 4 (Ai / Li), while the peripheral length of the outflow end (52) of the discharge port (50) is Lo. The reference lift amount of the valve body (61) is defined as ho, and is formed between the outlet end (52) of the discharge port (50) and the valve body (61). When the cross-sectional area of the outlet channel (70) is Ao = Lo × ho and the hydraulic diameter of the outlet channel (70) is Do = 4 (Ao / 2Lo), the discharge port (50) The ratio (Do / Di) of the hydraulic diameter Do of the outflow side channel (70) to the hydraulic diameter Di of the inflow end (51) is 0.25 or more and 0.5 or less.

  In the first invention, the discharge port (50) is formed in the stationary member (45) of the compressor (10). The inflow end (51) of the discharge port (50) communicates with the compression chamber (36). The outflow end (52) of the discharge port (50) is opened and closed by the valve body (61) of the discharge valve (60). When the valve body (61) of the discharge valve (60) covers the outflow end (52) of the discharge port (50), the backflow of fluid from the outside of the fixed side member (45) to the discharge port (50) Blocked by (61). In the state where the valve body (61) of the discharge valve (60) is lifted from the outflow end (52) of the discharge port (50), the fluid in the compression chamber (36) flows into the outflow end (52) of the discharge port (50). Flows out of the stationary member (45) through the gap between the valve body (61) and the valve body (61).

The peripheral length Li of the inflow end (51) of the discharge port (50) is the wet edge length of the inflow end (51) of the discharge port (50). Accordingly, the hydraulic diameter Di of the inflow end (51) of the discharge port (50) is expressed by the following equation 01.
Di = 4 (Ai / Li) (Equation 01)

In the state where the valve body (61) of the discharge valve (60) is lifted from the outflow end (52) of the discharge port (50), the outflow end (52) of the discharge port (50) and the valve body (61) are parallel. In this case, the distance between the outflow end (52) of the discharge port (50) and the valve body (61) (that is, the lift amount of the valve body (61)) is the same for the entire outflow end (52) of the discharge port (50). It is like. For this reason, the cross-sectional area Ao of the outflow side flow path (70) formed between the outflow end (52) of the discharge port (50) and the valve body (61) has a circumference of the outflow end of the discharge port (50). It is equal to the peripheral length Lo of (52), and the height is equal to the surface area of the cylinder (ie, Lo × h) equal to the lift amount h of the valve disc (61). However, for example, when the discharge valve (60) is a reed valve, the valve body (61) is inclined with respect to the outflow end (52) of the discharge port (50). The distance between the end (52) and the valve body (61) is not uniform throughout the outflow end (52) of the discharge port (50). Therefore, even in such a case, the cross-sectional area Ao of the outflow passage (70) is set in the same manner as when the lift amount of the valve body (61) is uniform over the entire outflow end (52) of the discharge port (50). A value representative of the distance between each part of the outflow end (52) of the discharge port (50) and the valve body (61) is defined as a reference lift amount ho so that it can be calculated. Then, the cross-sectional area Ao of the outflow side channel (70) is expressed by the following expression 02.
Ao = Lo x ho (Equation 02)

When the valve body (61) is parallel to the outflow end (52) of the discharge port (50), the outflow side flow path formed between the outflow end (52) of the discharge port (50) and the valve body (61) The wet edge length of (70) is twice the peripheral length Lo of the outflow end (52) of the discharge port (50). On the other hand, if the reference lift amount ho is used, even when the valve body (61) is inclined with respect to the outflow end (52) of the discharge port (50), the valve body (61) is connected to the outflow end ( 52) and can be handled in the same way. Therefore, even when the valve body (61) is inclined with respect to the outflow end (52) of the discharge port (50), the wet edge length of the outflow side channel (70) can be approximately 2 Lo. . Then, the hydraulic diameter Do of the outflow side channel (70) is expressed by the following equation 03.
Do = 4 (Ao / 2Lo) = 2ho (Equation 03)

In the first invention, the ratio (Do / Di) of the hydraulic diameter Do of the outflow channel (70) to the hydraulic diameter Di of the inflow end (51) of the discharge port (50) is 0.25 or more and 0.5 or less ( 0.25 ≦ Do / Di ≦ 0.5). As shown in Expression 03, the hydraulic diameter Do of the outflow side channel (70) is twice the reference lift amount ho. Therefore, in the present invention, the reference lift amount ho of the valve body (61) of the discharge valve (60) is set to a value corresponding to the hydraulic diameter Di of the inflow end (51) of the discharge port (50).

  According to a second aspect, in the first aspect, the ratio (Do / Di) of the hydraulic diameter Do of the outflow side passage (70) to the hydraulic diameter Di of the inflow end (51) of the discharge port (50) is set. 0.4 or less.

In the second invention, the ratio (Do / Di) of the hydraulic diameter Do of the outflow side flow path (70) to the hydraulic diameter Di of the inflow end (51) of the discharge port (50) is 0.25 or more and 0.4 or less ( 0.25 ≦ Do / Di ≦ 0.4). In this invention, as in the first invention, the reference lift amount ho of the valve body (61) of the discharge valve (60) is a value corresponding to the hydraulic diameter Di of the inflow end (51) of the discharge port (50). Set to

According to a third aspect of the present invention, in the first or second aspect of the invention, the fixed side member (45) is formed with a chamfered portion (56) over the entire circumference of the outflow end (52) of the discharge port (50). It is what is done.

In the third invention, the chamfered portion (56) of the stationary member (45) is formed over the entire circumference of the outflow end (52) of the discharge port (50). For this reason, in the portion near the outflow end (52) of the discharge port (50), the flow path cross-sectional area gradually expands toward the outflow end (52) of the discharge port (50). When the chamfered portion (56) is formed on the fixed side member (45), the area of the outflow end (52) of the discharge port (50) is larger than when the chamfered portion (56) is not formed. The area of the outflow end (52) of the discharge port (50) is the area of the portion of the valve body (61) that covers the outflow end (52) of the discharge port (50) where the pressure of the discharge port (50) acts (that is, , Pressure receiving area). For this reason, when the area of the outflow end (52) of the discharge port (50) increases, the pressure receiving area of the valve body (61) increases, and the valve body (61) is removed from the outflow end (52) of the discharge port (50). The force in the pulling direction increases.

According to a fourth aspect , in the third aspect , the height H of the chamfered portion (56) in the axial direction of the discharge port (50) and the direction in the direction orthogonal to the axial direction of the discharge port (50). The width W of the chamfered portion (56) satisfies the relationship 0 <H / W <0.5.

  Here, the greater the width W of the chamfered portion (56), the larger the pressure receiving area of the valve body (61) covering the outflow end (52) of the discharge port (50). On the other hand, the smaller the height H of the chamfered portion (56), the smaller the increase in the volume of the discharge port (50) due to the formation of the chamfered portion (56). The volume of the discharge port (50) is a dead volume that does not change even when the movable member (38) rotates. For this reason, in order to improve the efficiency of the compressor (10), it is desirable that the volume of the discharge port (50) is small.

In the fourth invention, the shape of the chamfered portion (56) formed on the fixed side member (45) is such that the height H and width W of the chamfered portion (56) are 0 <H / W <0.5. The shape will satisfy. That is, the height H of the chamfered portion (56) is suppressed to less than half of the width W of the chamfered portion (56). For this reason, while increasing the pressure receiving area of the valve body (61) covering the outflow end (52) of the discharge port (50), the amount of increase in the volume of the discharge port (50) can be kept low.

According to a fifth invention, in any one of the first to fourth inventions, a cross-sectional shape of the discharge port (50) is an oval or an ellipse.

In the fifth invention, the discharge port (50) having an oval or elliptical cross-sectional shape is formed in the stationary member (45).

  In the compressor (10) of the present invention, the ratio (Do / Di) of the hydraulic diameter Do of the outflow passage (70) to the hydraulic diameter Di of the inflow end (51) of the discharge port (50) is 0.5 or less. Thus, the reference lift amount ho of the valve element (61) of the discharge valve (60) is set. If the lift amount of the valve body (61) is set in this way, the reference lift amount ho of the valve body (61) becomes a relatively small value, and the outflow end (52) of the discharge port (50) and the valve body (61) The vortices generated when the fluid passes between them are reduced. Therefore, according to the present invention, the pressure loss when the fluid flows out from the discharge port (50) can be kept low, and the efficiency of the compressor (10) can be improved.

  By the way, if the discharge valve (60) is not closed at an appropriate timing, the fluid discharged from the compression chamber (36) through the discharge port (50) may flow back to the discharge port (50). On the other hand, if the lift amount of the valve body (61) of the discharge valve (60) is increased, the time required for the movement of the valve body (61) becomes longer. 52) The closing timing may be delayed from the appropriate timing. When the timing for the valve body (61) to close the outflow end (52) of the discharge port (50) is delayed, the amount of fluid that flows back from the outside of the fixed side member (45) to the compression chamber (36) increases, and compression occurs. The efficiency of the machine (10) decreases.

  On the other hand, when the valve body (61) closes the outflow end (52) of the discharge port (50) in the present invention, the reference lift amount ho of the valve body (61) is set to a relatively small value. For this reason, the delay of the timing when the valve body (61) closes the outflow end (52) of the discharge port (50) can be shortened, and the amount of fluid flowing back from the outside of the fixed side member (45) to the compression chamber (36) can be reduced. Can be reduced. Therefore, according to the present invention, the efficiency of the compressor (10) can be improved also in this respect.

  Here, in order to prevent the backflow of the fluid to the compression chamber (36), it is sufficient that the outflow end (52) of the discharge port (50) is closed at an appropriate timing by the valve body (61) of the discharge valve (60). It is. For this reason, if the lift amount of the valve body (61) of the discharge valve (60) is below a certain level, the efficiency of the compressor (10) can be improved even if the lift amount of the valve body (61) is further reduced. No longer contributes.

On the other hand, in the present invention, the ratio (Do / Di) of the “hydraulic diameter Do of the outflow passage (70) to the hydraulic diameter Di of the inflow end (51) of the discharge port (50) is 0.25. The reference lift amount ho of the valve body (61) of the discharge valve (60) is set so as to be 0.5 or less (0.25 ≦ Do / Di ≦ 0.5 ) . Therefore, according to the present invention, the reference lift amount ho of the valve body (61) can be set within a range in which the amount of fluid flowing back to the compression chamber (36) can be reduced.

  In particular, in the second aspect, the ratio (Do / Di) of the hydraulic diameter Do of the outflow side flow path (70) to the hydraulic diameter Di of the inflow end (51) of the discharge port (50) is 0.4 or less. As described above, the reference lift amount ho of the valve body (61) of the discharge valve (60) is set. For this reason, the delay of the timing which a valve body (61) closes the outflow end (52) of a discharge port (50) can be shortened further. Therefore, according to the present invention, the amount of fluid that flows back from the outside of the stationary member (45) to the compression chamber (36) can be further reduced, and as a result, the efficiency of the compressor (10) can be further improved. .

In the third aspect of the present invention, the chamfered portion (56) is formed in the stationary member (45) over the entire circumference of the outflow end (52) of the discharge port (50). For this reason, compared with the case where the chamfered part (56) is not formed in the stationary member (45), the area of the outflow end (52) of the discharge port (50) is enlarged. As a result, the pressure receiving area of the valve body (61) covering the outflow end (52) of the discharge port (50) can be increased, and the valve body (61) is pulled away from the outflow end (52) of the discharge port (50). The direction force can be increased. This reduces the difference between the internal pressure of the compression chamber (36) and the back pressure of the valve body (61) when the valve body (61) begins to move away from the outflow end (52) of the discharge port (50). The overcompression that compresses the fluid in the chamber (36) more than necessary can be suppressed, and the efficiency of the compressor (10) can be improved.

The chamfered portion (56) of the fourth aspect of the invention has a shape such that the height H and width W of the chamfered portion (56) satisfy the relationship 0 <H / W <0.5. For this reason, while increasing the pressure receiving area of the valve body (61) covering the outflow end (52) of the discharge port (50), the increase amount of the volume of the discharge port (50) can be kept low.

Drawing 1 is a longitudinal section of the compressor of an embodiment. FIG. 2 is a cross-sectional view of the compression mechanism showing the AA cross section of FIG. 1. FIG. 3 is a cross-sectional view showing the main part of the cross section of the compression mechanism along the major axis of the discharge port, where (A) shows the state where the discharge valve is closed, and (B) shows the state where the discharge valve is open. Show. FIG. 4 is a cross-sectional view showing the main part of the cross section of the compression mechanism along the minor axis of the discharge port. FIG. 5 is a cross-sectional view of the compression mechanism showing an enlarged main part of FIG. FIG. 6 is a plan view of the front head, and shows a portion of the front head near the outflow end of the discharge port. FIG. 7A is a perspective view showing the shape of an actual outflow side flow path, and FIG. 7B is a perspective view showing the shape of a virtual outflow side flow path. FIG. 8 is a table showing hydraulic diameter ratios Do / Di and the like for a plurality of reference lift amounts ho. 9 is a cross-sectional view of the main part of the front head showing the flow of the gas refrigerant flowing out from the discharge port. FIG. 9A is a cross-sectional view taken along line BB in FIG. 4 when the reference lift amount ho = 1.6 mm. 3 shows the CC cross section of FIG. 3, and FIG. 3B shows the BB cross section of FIG. 4 and the CC cross section of FIG. 3 when the reference lift amount ho = 0.8 mm. FIG. 10 is a graph showing simulation results when the reference lift amount ho = 1.4 mm and the reference lift amount ho = 1.6 mm. FIG. 10A shows the compression chamber during one rotation of the drive shaft. The change in the pressure and the lift amount of the valve body is shown, and (B) shows the change in the discharge flow rate of the refrigerant from the discharge port during one rotation of the drive shaft. FIG. 11 is a graph showing the simulation results when the reference lift amount ho = 1.2 mm and the reference lift amount ho = 1.6 mm. FIG. 11A shows the compression chamber during one rotation of the drive shaft. The change in the pressure and the lift amount of the valve body is shown, and (B) shows the change in the discharge flow rate of the refrigerant from the discharge port during one rotation of the drive shaft. FIG. 12 is a graph showing simulation results when the reference lift amount ho = 1.0 mm and the reference lift amount ho = 1.6 mm. FIG. 12A shows the compression chamber during one rotation of the drive shaft. The change in the pressure and the lift amount of the valve body is shown, and (B) shows the change in the discharge flow rate of the refrigerant from the discharge port during one rotation of the drive shaft. FIG. 13 is a graph showing simulation results when the reference lift amount ho = 0.8 mm and the reference lift amount ho = 1.6 mm. FIG. 13A shows the compression chamber during one rotation of the drive shaft. The change in the pressure and the lift amount of the valve body is shown, and (B) shows the change in the discharge flow rate of the refrigerant from the discharge port during one rotation of the drive shaft. FIG. 14 is a graph showing the relationship between the hydraulic diameter ratio Do / Di and the reverse flow rate of the refrigerant to the compression chamber. 15 is a cross-sectional view of the front head showing the shape of the discharge port of Modification 3 of the embodiment, in which (A) shows a cross-section corresponding to the BB cross-section of FIG. 4, and (B) shows FIG. A cross section corresponding to the CC cross section is shown. 16 is a cross-sectional view of the front head showing the shape of the discharge port of Modification 4 of the embodiment, in which (A) shows a cross-section corresponding to the BB cross-section of FIG. 4, and (B) shows FIG. A cross section corresponding to the CC cross section is shown. FIG. 17 is a plan view of a front head according to Modification 5 of the embodiment, and shows a portion of the front head near the outflow end of the discharge port. FIG. 18 is a cross-sectional view of a compression mechanism of Modification 6 of the embodiment, and shows a cross-section corresponding to FIG.

  Embodiments of the present invention will be described in detail with reference to the drawings. Note that the embodiments and modifications described below are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

  The compressor (10) of the present embodiment is provided in a refrigerant circuit that performs a vapor compression refrigeration cycle, and sucks and compresses refrigerant evaporated by an evaporator.

-Overall structure of the compressor-
As shown in FIG. 1, the compressor (10) of this embodiment is a hermetic compressor in which a compression mechanism (30) and an electric motor (20) are accommodated in a casing (11).

  The casing (11) is an upright cylindrical sealed container. The casing (11) includes a cylindrical body (12) and a pair of end plates (13, 14) that closes the end of the body (12). A suction pipe (15) is attached to the lower part of the trunk (12). A discharge pipe (16) is attached to the upper end plate (13).

  The electric motor (20) is disposed above the compression mechanism (30). The electric motor (20) includes a stator (21) and a rotor (22). The stator (21) is fixed to the body (12) of the casing (11). The rotor (22) is attached to a drive shaft (23) of a compression mechanism (30) described later.

  The compression mechanism (30) is disposed at the lower part in the casing (11). The compression mechanism (30) is a so-called oscillating piston type rotary fluid machine. The compression mechanism (30) includes a front head (31), a cylinder (32), and a rear head (33).

  The cylinder (32) is a thick disk-shaped member (see FIG. 2). A circular hole that forms a compression chamber (36) together with a piston (38) to be described later is formed at the center of the cylinder (32). The front head (31) is a plate-like member that closes the upper end surface of the cylinder (32). A main bearing (31a) that supports the drive shaft (23) protrudes from the center of the front head (31). The rear head (33) is a plate-like member that closes the lower end surface of the cylinder (32). A sub-bearing (33a) that supports the drive shaft (23) protrudes from the center of the rear head (33).

  The cylinder (32) is fixed to the body (12) of the casing (11). The front head (31), the cylinder (32), and the rear head (33) are fastened to each other by bolts, and constitute a fixed side member (45).

  The compression mechanism (30) includes a drive shaft (23). The drive shaft (23) includes a main shaft portion (24) and an eccentric portion (25). The eccentric portion (25) is disposed near the lower end of the main shaft portion (24). The eccentric portion (25) is formed in a cylindrical shape having a larger diameter than the main shaft portion (24), and is eccentric with respect to the main shaft portion (24). Although not shown, an oil supply passage is formed in the drive shaft (23). Lubricating oil collected at the bottom of the casing (11) is supplied to the sliding portions of the bearings (31a, 33a) and the compression mechanism (30) through the oil supply passage.

  As shown in FIG. 2, the compression mechanism (30) includes a piston (38) that is a movable member and a blade (43).

  The piston (38) is formed in a slightly thick cylindrical shape. An eccentric part (25) of the drive shaft (23) is rotatably fitted in the piston (38). The outer peripheral surface (39) of the piston (38) is in sliding contact with the inner peripheral surface (35) of the cylinder (32). In the compression mechanism (30), a compression chamber (36) is formed between the outer peripheral surface (39) of the piston (38) and the inner peripheral surface (35) of the cylinder (32).

  The blade (43) is a flat plate-like member protruding from the outer peripheral surface (39) of the piston (38), and is formed integrally with the piston (38). The blade (43) partitions the compression chamber (36) into a high pressure chamber (36a) and a low pressure chamber (36b).

  The compression mechanism (30) includes a pair of bushes (41). The pair of bushes (41) are fitted into the bush grooves (40) of the cylinder (32), and sandwich the blade (43) from both sides. The blade (43) integrated with the piston (38) is supported by the cylinder (32) through the bush (41).

  The cylinder (32) is formed with a suction port (42) penetrating the cylinder (32) in the radial direction. The suction port (42) communicates with the low pressure chamber (36b) of the compression chamber (36). One end of the suction port (42) opens to the inner peripheral surface (35) of the cylinder (32). The opening end of the suction port (42) on the inner peripheral surface (35) is provided at a position adjacent to the bush (41) (right next to the bush (41) in FIG. 2). On the other hand, the suction pipe (15) is inserted into the other end of the suction port (42).

  A discharge port (50) is formed in the front head (31). The discharge port (50) is a through hole that penetrates the front head (31) in the thickness direction (see FIG. 1). The discharge port (50) communicates with the high pressure chamber (36a) of the compression chamber (36). On the lower surface of the front head (31), the opening end of the discharge port (50) is located on the opposite side of the bush (41) from the suction port (42) (next to the left of the bush (41) in FIG. 2). Has been placed. The detailed shape of the discharge port (50) will be described later.

  The front head (31) is provided with a discharge valve (60) consisting of a reed valve. As shown in FIG. 3, the discharge valve (60) is attached to the upper surface of the front head (31). The discharge valve (60) includes a valve body (61), a valve presser (62), and a fixing pin (63).

  The valve body (61) is a thin and flat thin plate member. The material of the valve body (61) is, for example, spring steel. The valve body (61) is provided such that its tip end covers the outflow end (52) of the discharge port (50). When the discharge valve (60) is closed, the front surface (61a) of the valve body (61) is in close contact with the peripheral edge (52a) of the outflow end (52) of the discharge port (50). The valve presser (62) is a metal member having a slightly thick wall and high rigidity. The valve presser (62) is formed in an elongated plate shape corresponding to the shape of the valve body (61). Further, the tip of the valve presser (62) has a slightly curved shape upward. The valve presser (62) is disposed so as to overlap the valve body (61). The base end portion of the valve presser (62) and the base end portion of the valve body (61) are fixed to the front head (31) by a fixing pin (63).

  As shown in FIG. 3A, when the valve body (61) covers the outflow end (52) of the discharge port (50), the discharge port (50) is closed. On the other hand, as shown in FIGS. 3B and 4, when the valve body (61) is lifted from the outflow end (52) of the discharge port (50), the discharge port (50) is opened.

  Thus, the compression mechanism (30) of the present embodiment includes the cylinder (32), the front head (31) and the rear head (33) that are closing members for closing the end of the cylinder (32), and the cylinder. A piston (38) housed in (32) that rotates eccentrically, and a blade (43) that partitions the compression chamber (36) formed between the cylinder (32) and the piston (38) into a low pressure side and a high pressure side. A rotary fluid machine provided.

−Operation of compressor−
The operation of the compressor (10) will be described with reference to FIG.

  When the electric motor (20) is energized, the drive shaft (23) rotates in the clockwise direction in FIG. When the drive shaft (23) rotates, the piston (38) formed integrally with the blade (43) rotates eccentrically while swinging. When the piston (38) moves, the low pressure gas refrigerant is sucked into the low pressure chamber (36b) of the compression chamber (36) through the suction port (42), and at the same time, the high pressure chamber (36a) of the compression chamber (36). The gas refrigerant present in is compressed.

  Here, the gas pressure (in-dome pressure) in the internal space of the casing (11) acts on the back surface (61b) of the valve body (61) of the discharge valve (60). For this reason, while the gas pressure in the high pressure chamber (36a) is lower than the pressure in the dome, the discharge valve (60) is closed as shown in FIG. When the piston (38) moves and the gas pressure in the high pressure chamber (36a) gradually increases, and the gas pressure in the high pressure chamber (36a) exceeds the pressure in the dome, the valve body of the discharge valve (60) ( The tip of 61) moves away from the outflow end (52) of the discharge port (50). As a result, the discharge valve (60) is in the open state shown in FIG.

  When the discharge valve (60) is opened, the gas refrigerant in the high pressure chamber (36a) passes through the discharge port (50), and the gap between the outlet end (52) of the discharge port (50) and the valve body (61). And is discharged into the internal space of the casing (11) (that is, outside the compression mechanism (30)). The high-pressure gas refrigerant discharged from the compression mechanism (30) is led out of the casing (11) through the discharge pipe (16).

-Shape of discharge port-
The shape of the discharge port (50) will be described in detail with reference to FIGS.

  The discharge port (50) is a straight through hole that penetrates the front head (31) in the plate thickness direction (see FIG. 5). The inflow end (51) of the discharge port (50) opens to the front surface of the front head (31) (that is, the surface on the cylinder (32) side). On the other hand, the outflow end (52) of the discharge port (50) opens to the back surface of the front head (31) (that is, the surface opposite to the cylinder (32)). On the back surface of the front head (31), the portion surrounding the outflow end (52) of the discharge port (50) is a sheet portion (55) that is one step higher than the surroundings.

  The flow path cross section of the discharge port (50) (that is, the cross section orthogonal to the axial direction of the discharge port (50)) is an oval (see FIG. 6). The discharge port (50) is arranged so that the minor axis thereof is along the radial direction of the inner peripheral surface (35) of the cylinder (32) (see FIG. 2).

  A chamfered portion (56) is formed on the front head (31) along the peripheral edge (52a) of the outflow end (52) of the discharge port (50). The chamfered portion (56) is formed over the entire circumference of the outflow end (52) of the discharge port (50) (see FIG. 6). The chamfered portion (56) has an axial height H of the discharge port (50) and a width W in a direction perpendicular to the axial direction of the discharge port (50) over the entire circumference of the chamfered portion (56). It is constant (see FIG. 5). In the present embodiment, the height H and width W of the chamfered portion (56) satisfy the relationship of 0 <H / W <0.5. That is, the height H of the chamfered portion (56) is less than half the width W of the chamfered portion (56) (0 <H <W / 2).

In the discharge port (50), a portion below the chamfered portion (56) constitutes a main passage portion (53). The cross section of the flow path of the main passage portion (53) has an elliptical shape in which the radius of curvature of the arc portion is Ri and the length of the straight portion is Ls. Moreover, the shape of the flow path cross section of the main passage portion (53) is constant over the entire length. In other words, the main passage section (53), the major axis of the channel cross section length D ₁ and a short diameter length of D ₂ has a constant over the entire length of the main passage portion (53). Therefore, the shape of the inflow end (51) of the discharge port (50) is also an oval shape in which the radius of curvature of the arc portion is Ri and the length of the straight portion is Ls.

  On the other hand, the shape of the outflow end (52) of the discharge port (50) is an oval that is slightly larger than the inflow end (51) of the discharge port (50). Specifically, the shape of the outflow end (52) of the discharge port (50) is an oval shape in which the radius of curvature of the arc portion is Ro = Ri + W and the length of the linear portion is Ls.

  In the inflow end (51) of the discharge port (50) of the present embodiment, the radius of curvature of the arc portion is Ri = 2.1 mm, and the length of the straight portion is Ls = 5.3 mm. The outflow end (52) of the discharge port (50) has a radius of curvature of the arc portion of Ro = 3.1 mm and a length of the straight portion of Ls = 5.3 mm. Further, the ratio (H / W) of the height H to the width W of the chamfered portion (56) of the discharge port (50) is 0.5 (H / W = 0.5). However, the numerical values shown here are merely examples.

  Here, when the chamfered portion (56) is formed on the front head (31), the area of the outflow end (52) of the discharge port (50) is larger than when the chamfered portion (56) is not formed. Expands. The area of the outflow end (52) of the discharge port (50) is equal to the area of the front surface (61a) of the valve body (61) where the pressure of the discharge port (50) acts (that is, the pressure receiving area). For this reason, when the area of the outflow end (52) of the discharge port (50) increases, the pressure receiving area of the valve body (61) increases, and the valve body (61) is removed from the outflow end (52) of the discharge port (50). The force in the pulling direction increases.

  When the force in the direction of pulling the valve body (61) away from the outflow end (52) of the discharge port (50) increases, “compression” occurs when the valve body (61) begins to move away from the outflow end (52) of the discharge port (50). The difference between the “gas pressure in the chamber (36)” and the “gas pressure acting on the back surface (61b) of the valve body (61)” is reduced. For this reason, the loss (so-called overcompression loss) resulting from compressing the gas refrigerant in the compression chamber (36) more than necessary is reduced.

  On the other hand, if the width W of the chamfered portion (56) is the same, the smaller the height H of the chamfered portion (56) is, the more the volume of the discharge port (50) is increased by forming the chamfered portion (56). Get smaller. The volume of the discharge port (50) is a dead volume that does not change even when the piston (38) rotates. For this reason, in order to improve the efficiency of the compressor (10), it is desirable to make the volume of the discharge port (50) as small as possible.

  Therefore, in the compressor (10) of the present embodiment, the height of the chamfered portion (56) is considered in consideration of the improvement in efficiency due to the reduction in overcompression loss and the reduction in efficiency due to the increase in dead volume. H is less than half the width W of the chamfered portion (56).

− Lift amount of valve body of discharge valve −
In the compressor (10) of the present embodiment, the pressure loss when the gas refrigerant is discharged from the compression mechanism (30) is suppressed to a low level, and the compressor is caused by the closing delay of the valve body (61) of the discharge valve (60). The lift amount of the valve body (61) of the discharge valve (60) is set so that the efficiency reduction of (10) is suppressed. As will be described in detail later, in the compressor (10) of the present embodiment, the reference lift amount ho of the valve body (61) of the discharge valve (60) is the hydraulic diameter Di of the inflow end (51) of the discharge port (50). It is set based on.

<Hydraulic diameter Di at the inlet end of the discharge port>
As described above, the shape of the inflow end (51) of the discharge port (50) is an oval shape having the radius of curvature Ri of the arc portion and the length Ls of the straight portion. Therefore, the length (periphery length Li) of the peripheral edge (51a) of the inflow end (51) of the discharge port (50) is expressed by the following expression 1, and the area Ai is expressed by the following expression 2. The peripheral length Li of the inflow end (51) of the discharge port (50) is the wet edge length of the inflow end (51) of the discharge port (50). Accordingly, the hydraulic diameter Di of the inflow end (51) of the discharge port (50) is expressed by the following Equation 3. Equation 3 is the same as Equation 01 above.
Li = 2πRi + 2Ls (Equation 1)
Ai = πRi ² + 2Ri · Ls (Equation 2)
Di = 4 (Ai / Li) (Equation 3)

In the inflow end (51) of the discharge port (50) of the present embodiment, the radius of curvature of the arc portion is Ri = 2.1 mm, and the length of the straight portion is Ls = 5.3 mm. Accordingly, the peripheral length Li is 23.8 mm, the area Ai is 36.1Mm ^2, the hydraulic diameter Di is 6.1 mm.

<Reference lift amount ho of the valve body of the discharge valve>
As shown in FIG. 5, the reference lift amount ho of the valve body (61) of the discharge valve (60) is the maximum lift amount of the valve body (61) on the center line CL of the discharge port (50). In other words, the reference lift amount ho is the “discharge port (50) on the center line CL of the discharge port (50) when the entire back surface (61b) of the valve body (61) is in contact with the valve presser (62). ) Outflow end (52) "to the" front surface (61a) of the valve body (61) ".

  The center line CL of the discharge port (50) is the intersection of the major axis and minor axis at the inflow end (51) of the ejection port (50) and the major axis and minor axis at the outflow end (52) of the discharge port (50). A straight line passing through the intersection. The center line CL is orthogonal to the inflow end (51) and the outflow end (52) of the discharge port (50).

When the entire back surface (61b) of the valve body (61) is in contact with the valve retainer (62), the front surface (61a) of the valve body (61) is in contact with the outflow end (52) of the discharge port (50). It is inclined. For this reason, as shown in FIG. 5, the distance from the outflow end (52) of the discharge port (50) to the front surface (61a) of the valve body (61) (that is, the lift amount of the valve body (61)) is the maximum. The value is h ₁ and the minimum value is h ₂ .

<Hydraulic diameter Do of the outflow channel>
When the valve body (61) of the discharge valve (60) is lifted from the outflow end (52) of the discharge port (50), it flows out between the outflow end (52) of the discharge port (50) and the valve body (61). A side flow path (70) is formed. The gas refrigerant discharged from the discharge port (50) passes through the outflow side channel (70).

As described above, the shape of the outflow end (52) of the discharge port (50) is an oval. Further, as shown in FIG. 5, when the valve body (61) is lifted from the outflow end (52) of the discharge port (50), the front surface (61a) of the valve body (61) is discharged from the discharge port (50). The state is inclined with respect to the end (52). For this reason, the cross-sectional shape of the outflow side flow path (70) is a shape as shown in FIG. 7A (that is, the same shape as the side surface of the cylindrical body whose upper surface is inclined with respect to the lower surface). The lower peripheral edge (72) of the outflow side channel (70) has the same oval shape as the peripheral edge (52a) of the outflow end (52) of the discharge port (50). On the other hand, the upper peripheral edge (71) of the outflow channel (70) has a shape obtained by projecting the peripheral edge (52a) of the outflow end (52) of the discharge port (50) onto the front surface (61a) of the valve body (61). Become. The height of the outflow-side passage (70), the maximum value of h _1, and the minimum value becomes h _2.

By the way, in a state where the entire back surface (61b) of the valve body (61) is in contact with the valve presser (62), the front surface (61a) of the valve body (61) is a flat surface that is not substantially curved. For this reason, the reference lift amount ho of the valve body (61) is substantially equal to the average value ((h ₁ + h ₂ ) / 2) of the maximum value h ₁ and the minimum value h ₂ of the lift amount of the valve body (61). equal. Then, the channel cross-sectional area of the actual outflow side channel (70) shown in FIG. 7 (A) is substantially the same as the channel cross-sectional area of the virtual outflow side channel (75) shown in FIG. 7 (B). Is equal to

  In the hypothetical outflow channel (75) shown in FIG. 7B, the front surface (61a) of the valve body (61) is parallel to the outflow end (52) of the discharge port (50), and the discharge port (50) Between the outlet end (52) of the discharge port (50) and the valve body (61) when the distance from the outlet end (52) of the valve to the front surface (61a) of the valve body (61) is the reference lift amount ho It is a channel formed. Moreover, the cross-sectional shape of this virtual outflow side flow path (75) is the same shape as the side surface of the cylindrical body whose upper surface and lower surface are parallel.

  In this embodiment, the virtual outflow side flow path (75) shown in FIG. 7B is treated as being substantially equivalent to the actual outflow side flow path (70) shown in FIG. Then, the hydraulic diameter of the actual outflow side channel (70) shown in FIG. 7 (A) is treated as being substantially equal to the hydraulic diameter of the virtual outflow side channel (75) shown in FIG. 7 (B). It calculates based on the following formulas 4-6.

The shape of the outflow end (52) of the discharge port (50) is an oval having a radius of curvature Ro of the arc portion and a length Ls of the straight portion. Therefore, the length (periphery length Lo) of the peripheral edge (52a) of the outflow end (52) of the discharge port (50) is expressed by the following equation (4).
Lo = 2πRo + 2Ls (4)

The upper periphery (76) and the lower periphery (77) of the virtual outflow channel (75) are shaped like the lower periphery (72) of the actual outflow channel (70). Is the same as the shape of the outflow end (52) of the discharge port (50). The peripheral length of the virtual outflow side channel (75) is equal to the peripheral length Lo of the outflow end (52) of the discharge port (50). For this reason, the channel cross-sectional area Ao of the virtual outflow side channel (75) is expressed by Equation 5. Expression 5 is the same as Expression 02 described above.
Ao = Lo x ho (Equation 5)

The wet edge length of the virtual outflow side channel (75) is the sum of the upper peripheral length and the lower peripheral length. Accordingly, the wetting edge length of the virtual outflow side channel (75) is 2 Lo. For this reason, the hydraulic diameter Do of the virtual outflow side channel (75) is expressed by Equation 6. In the present embodiment, it is assumed that the actual hydraulic diameter of the outflow channel (70) is equal to the hydraulic diameter Do calculated using Equation 6. Equation 6 is the same as Equation 03 above.
Do = 4 (Ao / 2Lo) = 2ho (Equation 6)

  In the outlet port (52) of the discharge port (50) of the present embodiment, the radius of curvature of the arc portion is Ro = 3.1 mm, and the length of the straight portion is Ls = 5.3 mm. Accordingly, the peripheral length Lo of the outflow end (52) of the discharge port (50) is 30.1 mm. On the other hand, the channel cross-sectional area Ao of the virtual outflow side channel (75) and its hydraulic diameter Do are functions of the reference lift amount ho. FIG. 8 shows the values of the channel cross-sectional area Ao and the hydraulic diameter Do for each case where the reference lift amount ho is 0.8 mm, 1.0 mm, 1.2 mm, 1.4 mm, and 1.6 mm.

<Hydraulic diameter ratio Do / Di>
In the compressor (10) of the present embodiment, the ratio (Do / Di) of the hydraulic diameter Do of the outflow side channel (70) to the hydraulic diameter Di of the inflow end (51) of the discharge port (50) is expressed by the following equation (7). The reference lift amount ho of the valve body (61) of the discharge valve (60) is set so as to satisfy the relationship indicated by. As shown in Equation 6, Do = 2ho. Therefore, in the compressor (10) of the present embodiment, the reference lift amount ho of the valve body (61) of the discharge valve (60) is set to a value within the numerical range shown in Expression 8.
0.25 ≦ Do / Di ≦ 0.5 (Expression 7)
Di / 8≤ho≤Di / 4 (Equation 8)

  FIG. 8 shows the hydraulic diameter Do of the outflow channel (70) and the hydraulic diameter ratio for each case where the reference lift ho is 0.8 mm, 1.0 mm, 1.2 mm, 1.4 mm, and 1.6 mm. Shows the value of Do / Di. In each case where the reference lift amount ho is 0.8 mm, 1.0 mm, 1.2 mm, and 1.4 mm, the hydraulic diameter ratio Do / Di is a value of 0.25 or more and 0.5 or less. On the other hand, when the reference lift amount ho is 1.6 mm, the hydraulic diameter ratio Do / Di is larger than 0.5. Therefore, each case where the reference lift amount ho is 0.8 mm, 1.0 mm, 1.2 mm, and 1.4 mm is an embodiment of the present invention. On the other hand, when the reference lift amount ho is 1.6 mm, this is a comparative example that is not an embodiment of the present invention.

In addition, the value of the hydraulic diameter ratio Do / Di shown in FIG. 8 is a value calculated using the following formula 9. Expression 9 is an expression obtained by substituting Expressions 1 to 3 and Expression 6 into Do / Di.
Do / Di = 2ho / 4 (Ai / Li) = ho · Li / 2Ai
= Ho (πRi + Ls) / Ri (πRi + 2Ls) (Equation 9)

-Numerical range of hydraulic diameter ratio Do / Di-
The reason why it is desirable to set the reference lift amount ho of the valve body (61) of the discharge valve (60) so that the hydraulic diameter ratio Do / Di is 0.25 or more and 0.5 or less will be described.

<Pressure loss of discharged refrigerant>
As shown in FIG. 9, the gas refrigerant discharged from the compression mechanism (30) is first ejected from the outlet end (52) of the discharge port (50) toward the valve body (61) of the discharge valve (60), Next, it collides with the front surface (61a) of the valve body (61) and its flow direction changes, and then flows so as to spread around the outflow end (52) of the discharge port (50).

  As shown in FIG. 9A, in the case of the reference lift amount ho = 1.6 mm (0.5 <Do / Di), a relatively large vertical vortex around the outflow end (52) of the discharge port (50). Occurs. This vertical vortex prevents the flow of the gas refrigerant that is about to flow out from the outflow side flow path (70) (that is, the gap between the outflow end (52) of the discharge port (50) and the valve body (61)). Accordingly, the portion of the outflow side channel (70) through which the gas refrigerant can pass is only a small portion near the valve body (61). For this reason, although the channel cross-sectional area of the outflow side channel (70) is relatively large, the pressure loss when the gas refrigerant passes through the outflow side channel (70) is not so small.

  On the other hand, as shown in FIG. 9B, when the reference lift amount ho = 0.8 mm (0.25 ≦ Do / Di ≦ 0.5), the periphery of the outflow end (52) of the discharge port (50). However, the vertical vortex does not substantially occur. The gas refrigerant ejected from the outflow end (52) of the discharge port (50) immediately collides with the valve body (61), changes its flow direction, and passes through almost the entire outflow channel (70). . For this reason, the pressure when the gas refrigerant passes through the outflow side passage (70) although the flow passage cross-sectional area of the outflow side passage (70) is narrower than in the case of the reference lift amount ho = 1.6 mm. The loss is about the same as when the reference lift amount ho = 1.6 mm.

<Pulsation of discharged refrigerant>
The vertical vortex shown in FIG. 9A repeats generation and disappearance several times in one discharge stroke. As described above, the vertical vortex hinders the flow of the gas refrigerant that is about to flow out from the outflow channel (70). For this reason, every time the vertical vortex is repeatedly generated and disappeared, the flow rate of the gas refrigerant flowing out from the outflow side flow path (70) changes.

  10B, FIG. 11B, FIG. 12B, and FIG. 13B show the mass flow rate of the gas refrigerant discharged from the discharge port (50) of the compression mechanism (30) (that is, discharge). Change in flow rate). For example, in FIG. 10B, when the discharge valve (60) starts to move away from the outflow end (52) of the discharge port (50) when the rotation angle of the drive shaft (23) is around 230 °, the discharge flow rate is It will increase rapidly. The discharge flow rate becomes maximum when the rotation angle of the drive shaft (23) is around 250 °. Thereafter, the discharge flow rate fluctuates relatively greatly despite the lift amount of the valve body (61) being substantially constant. The fluctuation of the discharge flow rate in this discharge stroke is caused by the generation and disappearance of the vertical vortex formed around the outflow end (52) of the discharge port (50).

  Since fluctuations in the discharge flow rate cause vibration and noise of the compressor (10), it is desirable that the flow rate be as small as possible. 10 (B), FIG. 11 (B), FIG. 12 (B), and FIG. 13 (B), the fluctuation range of the discharge flow rate in the discharge stroke is the reference lift amount ho = 0.8 mm, The cases of 1.0 mm, 1.2 mm, and 1.4 mm are smaller than the case of the reference lift amount ho = 1.6 mm. Further, the fluctuation range of the discharge flow rate in the discharge stroke decreases as the reference lift amount ho decreases. Therefore, in the compressor (10) of the present embodiment, the reference lift amount ho of the valve body (61) of the discharge valve (60) is set so that the hydraulic diameter ratio Do / Di is 0.5 or less.

<Delay valve closing delay>
When the discharge valve (60) opens and closes, the tip of the valve body (61) moves due to the elastic deformation of the valve body (61). As the reference lift amount ho of the valve body (61) is larger, the moving distance of the valve body (61) when the discharge valve (60) is opened and closed becomes longer. When the moving distance of the valve body (61) becomes longer, the time required for opening and closing the discharge valve (60) becomes longer. For this reason, if the reference lift amount ho of the valve body (61) is increased too much, the valve body (61) will move to the outflow end (52 of the discharge port (50) despite the timing when the discharge valve (60) should be closed. ) Will occur (so-called closing delay phenomenon). For example, as shown in FIG. 10A, when the reference lift amount ho = 1.6 mm, the lift amount of the valve disc (61) even when the rotation angle of the drive shaft (23) reaches 360 °. Is about 0.6 mm.

  When the closing delay phenomenon occurs, the compression chamber (36) in the initial stage of the compression stroke communicates with the internal space of the casing (11) via the discharge port (50), and as a result, the internal space of the casing (11) The existing high-pressure gas refrigerant flows backward through the discharge port (50) to the compression chamber (36). For this reason, when the closing delay phenomenon occurs, the mass flow rate of the refrigerant discharged from the compression mechanism (30) per unit time decreases, and the efficiency of the compressor (10) decreases. And in order to suppress the efficiency fall of the compressor (10) resulting from the closing delay phenomenon of the discharge valve (60), it is desirable to make the reference lift amount ho of the valve body (61) of the discharge valve (60) as small as possible. .

  However, if the reference lift amount ho of the valve body (61) of the discharge valve (60) is too small, the pressure loss when the refrigerant is discharged from the compression mechanism (30) may become too large. On the other hand, as shown in FIG. 14, when the hydraulic diameter ratio Do / Di is relatively large, the reverse flow rate of the refrigerant to the compression chamber (36) gradually decreases as the hydraulic diameter ratio Do / Di decreases. However, when the hydraulic diameter ratio Do / Di is less than 0.25, the reverse flow rate of the refrigerant to the compression chamber (36) hardly decreases even if the hydraulic diameter ratio Do / Di is reduced. Therefore, in the compressor (10) of this embodiment, the reference lift amount ho of the valve element (61) of the discharge valve (60) is set so that the hydraulic diameter ratio Do / Di is 0.25 or more.

-Effect of the embodiment-
In the compressor (10) of the present embodiment, the reference lift amount ho of the valve body (61) of the discharge valve (60) is set so that the hydraulic diameter ratio Do / Di is 0.25 or more and 0.5 or less. . For this reason, the time required to open and close the valve body (61) can be reduced by suppressing the reference lift amount ho of the valve body (61) without increasing the pressure loss of the refrigerant discharged from the compression mechanism (30). Can be shortened. When the time required for opening and closing the valve body (61) is shortened, the amount of the refrigerant flowing back to the compression chamber (36) due to the delay in closing the valve body (61) decreases. Therefore, according to the present embodiment, the compressor (10) is reduced by reducing the amount of refrigerant flowing back to the compression chamber (36) while avoiding the efficiency reduction of the compression chamber (36) due to the increase in pressure loss of the discharged refrigerant. ) Efficiency can be improved.

  Here, as the rotational speed of the compression mechanism (30) increases, the time required for one discharge stroke is shortened. For this reason, as the rotational speed of the compression mechanism (30) increases, it is required to shorten the time required to open and close the valve body (61). If the reference lift amount ho of the valve body (61) of the discharge valve (60) is set so that the hydraulic diameter ratio Do / Di is not less than 0.25 and not more than 0.5, the rotational speed of the compression mechanism (30) is set. Even when the speed is considerably high (for example, 120 revolutions per second or more), adverse effects due to the delay in closing the valve body (61) can be suppressed.

  In the compressor (10) of the present embodiment, the height H and width W of the chamfered portion (56) satisfy the relationship of 0 <H / W <0.5. That is, in the present embodiment, the chamfered portion (56) has a relatively gentle inclination. Therefore, the discharge port resulting from forming the chamfered portion (56) while expanding the area (pressure receiving area) of the discharge port (50) where the pressure of the discharge port (50) acts on the front surface (61a) of the valve body (61). The increase in volume of (50) can be kept small. Therefore, according to this embodiment, the efficiency of the compressor (10) can be improved by reducing the overcompression loss while suppressing the efficiency reduction of the compressor (10) due to the increase in dead volume.

-Modification 1 of embodiment-
In the compressor (10) of the present embodiment, the reference lift amount ho of the valve body (61) of the discharge valve (60) is set so that the hydraulic diameter ratio Do / Di is 0.25 or more and 0.4 or less. Is more desirable.

  Here, when the valve body (61) is separated from the seat portion (55) when the rotation angle of the drive shaft (23) reaches 360 °, the internal space of the casing (11) becomes the discharge port (50) and There is a possibility that the amount of refrigerant that communicates with the suction port (42) via the compression chamber (36) and flows backward from the internal space of the casing (11) to the compression chamber (36) may be excessive.

  On the other hand, as shown in FIG. 11, when the hydraulic diameter ratio Do / Di = 0.4, the lift amount of the valve disc (61) becomes zero when the rotation angle of the drive shaft (23) reaches 360 °. Become. That is, when the rotation angle of the drive shaft (23) reaches 360 °, the discharge port (50) is completely blocked by the valve body (61). Further, as shown in FIGS. 12 and 13, as the hydraulic diameter ratio Do / Di becomes smaller, the time when the lift amount of the valve body (61) becomes zero becomes earlier.

  Accordingly, if the reference lift amount ho of the valve body (61) of the discharge valve (60) is set so that the hydraulic diameter ratio Do / Di is not less than 0.25 and not more than 0.4 as in the present modification, the compression chamber The amount of refrigerant flowing back to (36) can be further reliably reduced. This point will be described with reference to FIG.

Vmin shown in FIG. 14 is a lower limit value of the reverse flow rate of the refrigerant to the compression chamber (36). That is, due to the structure of the compressor (10), the reverse flow rate of the refrigerant to the compression chamber (36) cannot be made zero. For example, it is actually impossible to reduce the volume of the discharge port (50) to zero. Then, the amount exceeding the lower limit value Vmin becomes the reverse flow rate of the refrigerant to the compression chamber (36) that can be reduced. As shown in the figure, reverse flow of refrigerant to reduce possible compression chamber (36), if the hydraulic diameter ratio Do / Di = 0.53 is [Delta] V _1, the hydraulic diameter ratio Do / Di = 0. in the case of 4, which is a ΔV _2.

[Delta] V ₂ is less than half of _{ΔV 1 (ΔV 2 <ΔV 1} /2). Accordingly, if the reference lift amount ho of the valve body (61) of the discharge valve (60) is set so that the hydraulic diameter ratio Do / Di is 0.4 or less, the reverse flow rate of the refrigerant to the compression chamber (36) is reduced. It can be greatly reduced. For this reason, according to this modification, the efficiency of a compressor (10) can be improved reliably.

-Modification 2 of embodiment-
As shown in FIG. 8, when the reference lift amount ho of the valve body (61) of the discharge valve (60) is set so that the hydraulic diameter ratio Do / Di = 0.4, a virtual outflow side flow path (75 ) Is substantially equal to the area Ai of the inflow end (51) of the discharge port (50). When the reference lift amount ho of the valve element (61) of the discharge valve (60) is set so that the hydraulic diameter ratio Do / Di is less than 0.4, the flow path of the virtual outflow side flow path (75) The cross-sectional area Ao is smaller than the area Ai of the inflow end (51) of the discharge port (50). Thus, in the compressor (10) of the present embodiment, the channel cross-sectional area Ao of the virtual outflow side channel (75) is equal to or less than the area Ai of the inflow end (51) of the discharge port (50) (Ao ≦ Ai). It is desirable to set the reference lift amount ho of the valve body (61) of the discharge valve (60) so that

—Modification 3 of Embodiment—
As shown in FIG. 15, in the compressor (10) of the present embodiment, the flow passage cross-sectional area of the main passage portion (53) of the discharge port (50) flows out from the inflow end (51) of the discharge port (50). It may be gradually enlarged toward the end (52). In this modification, the wall surface forming the main passage portion (53) of the discharge port (50) is a conical surface centered on the center line CL of the discharge port (50). Further, in FIG. 15, the major axis length D ₁₂ of the upper end of the main passage portion (53) is longer than the major axis length D ₁₁ of the lower end, short necked length D ₂₂ of the upper end of the main passage portion (53) thereof It is longer than the major axis length D ₂₁ at the lower end.

-Modification 4 of the embodiment-
As shown in FIG. 16, in the compressor (10) of the present embodiment, the chamfered portion (56) may be omitted. The shape of the flow path cross section of the discharge port (50) of the present modification is a constant oval shape from the inflow end (51) to the outflow end (52) of the discharge port (50).

-Modification 5 of embodiment-
As shown in FIG. 17, in the compressor (10) of the present embodiment, the discharge port (50) may have an elliptical cross-sectional shape. Also in this modification, a chamfered portion (56) is formed on the front head (31) over the entire periphery of the peripheral edge (52a) of the outflow end (52) of the discharge port (50). Similar to the chamfered portion (56) shown in FIGS. 5 and 6, the height H and width W of the chamfered portion (56) of the present modified example are the peripheral edge (52a) of the outflow end (52) of the discharge port (50). Is constant over the entire circumference. In addition, the cross-sectional shape of the discharge port (50) of the present modification is not limited to a strict ellipse having two focal points. It may be.

-Modification 6 of embodiment-
As shown in FIG. 18, the compression mechanism (30) of the compressor (10) of this embodiment is a rolling piston type rotary fluid machine in which a blade (43) is formed separately from a piston (38). May be. In the compression mechanism (30) of the present modification, a flat blade (43) is slidably fitted into a blade groove extending in the radial direction of the cylinder (32), and the bush (41) is omitted. The blade (43) is pressed against the outer peripheral surface (39) of the piston (38) by the spring (44), and the tip thereof is in sliding contact with the outer peripheral surface (39) of the piston (38).

  In the compression mechanism (30) shown in FIG. 18, the cross-sectional shape of the discharge port (50) is circular, but the cross-sectional shape of the discharge port (50) of this modification is as shown in FIG. It may be oval or elliptical as shown in FIG.

  As described above, the present invention is useful for a compressor provided with a discharge valve.

10 Compressor
30 Compression mechanism
36 Compression chamber
38 Piston (movable member)
45 Fixed side member
50 Discharge port
51 Inlet end
52 Outflow end
56 Chamfer
60 Discharge valve
61 Disc

Claims (5)

A fixed side member (45) that forms a compression chamber (36); and a movable side member (38) that is rotationally driven to change the volume of the compression chamber (36), and fluid is supplied to the compression chamber (36). A compressor that inhales and compresses,
The fixed side member (45) is formed with a discharge port (50) that passes through the fixed side member (45) and leads the fluid from the compression chamber (36), and the discharge port (50) A discharge valve (60) that opens and closes is provided,
The discharge valve (60) closes the discharge port (50) by covering the outflow end (52) of the discharge port (50) and floats up from the outflow end (52) of the discharge port (50). It has a valve body (61) that opens the discharge port (50),
The area of the inflow end (51) of the discharge port (50) is Ai, the peripheral length of the inflow end (51) is Li, and the hydraulic diameter of the inflow end (51) is Di = 4 (Ai / Li). While
The peripheral length of the outflow end (52) of the discharge port (50) is Lo, the reference lift amount of the valve body (61) is ho, the outflow end (52) of the discharge port (50) and the valve body ( 61) When the cross-sectional area of the outflow side channel (70) formed during A) is Ao = Lo × ho and the hydraulic diameter of the outflow side channel (70) is Do = 4 (Ao / 2Lo) ,
The ratio (Do / Di) of the hydraulic diameter Do of the outflow side channel (70) to the hydraulic diameter Di of the inflow end (51) of the discharge port (50) is 0.25 or more and 0.5 or less. Compressor. In claim 1,
The ratio (Do / Di) of the hydraulic diameter Do of the outflow side channel (70) to the hydraulic diameter Di of the inflow end (51) of the discharge port (50) is 0.4 or less. . In claim 1 or 2 ,
The compressor characterized in that the fixed side member (45) is formed with a chamfered portion (56) over the entire circumference of the outflow end (52) of the discharge port (50). In claim 5 ,
The height H of the chamfered portion (56) in the axial direction of the discharge port (50) and the width W of the chamfered portion (56) in the direction orthogonal to the axial direction of the discharge port (50) are 0 < A compressor characterized by satisfying a relationship of H / W <0.5. In any one of Claims 1 thru | or 4 ,
The compressor characterized in that a cross-sectional shape of the discharge port (50) is oval or elliptical.

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