JP2017072104A - Compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compressor that can optimize a volumetric change rate of a fluid chamber to a desired behavior while an eccentric movable part rotates one rotation.SOLUTION: The compressor (10) includes: an electric motor (20); a rotation shaft (30) rotatably driven by the electric motor (20); and a compression mechanism (50) having the eccentric movable part (60) that is rotatably driven by the rotation shaft (30) to compress fluid. The rotation shaft (30) is provided with a speed changing mechanism (70) for changing a rotation speed of the eccentric movable part (60).SELECTED DRAWING: Figure 3

Description

    The present invention relates to a compressor.

    Conventionally, a compressor for compressing a fluid is known. As a compressor, there is a rotary compressor in which a substantially annular piston (eccentric movable part) rotates eccentrically in a cylinder chamber. In the rotary compressor, the rotating shaft is rotationally driven by an electric motor. Then, the eccentric part of the rotating shaft rotates eccentrically, and the piston is driven to rotate. Thereby, the volume of the low pressure chamber and the high pressure chamber of the cylinder chamber changes. As a result, the fluid is compressed as the volume of the high pressure chamber decreases.

JP 2011-21598 A

    By the way, in a rotary compressor, for example, while the piston rotates once in the cylinder chamber, the volume change rate is large especially when the piston passes the bottom dead center (that is, the position where the rotation angle of the eccentric part reaches 180 °). Become. As a result, in the compression mechanism, the peak of the compression torque becomes large when the piston passes through the bottom dead center. Due to such pulsation of the compression torque, there arises a problem that the motor efficiency is reduced and vibration and noise are increased.

    For example, in the compression mechanism, when the volume change rate of the low pressure chamber when the fluid is sucked into the low pressure chamber from the suction port increases, the flow rate of the fluid flowing through the suction port increases. In this case, the pressure loss of the fluid flowing through the suction port increases, leading to a decrease in the efficiency of illustration.

    Further, for example, in the compression mechanism, when the volume change rate of the high pressure chamber increases when the fluid is discharged from the high pressure chamber (also referred to as a compression chamber) to the discharge port, the flow velocity of the fluid flowing through the discharge port increases. In this case, the pressure loss of the fluid flowing through the discharge port increases, leading to a decrease in the efficiency of illustration.

    As described above, in the compression mechanism, various problems are caused as the volume change rate of the fluid chamber (including the low pressure chamber and the high pressure chamber) varies.

    The present invention has been made in view of this point, and an object of the present invention is to provide a compressor capable of optimizing the volume change rate of a fluid chamber to a desired behavior when the eccentric movable portion makes one rotation. is there.

    A first invention is directed to a compressor, and includes an electric motor (20), a rotating shaft (30) that is rotationally driven by the electric motor (20), and an eccentric movable portion (60) that is rotationally driven by the rotating shaft (30). And a compression mechanism (50) for compressing fluid, and the rotating shaft (30) has a speed variation mechanism (70) for varying the rotational speed of the eccentric movable part (60).

    In the first invention, when the electric motor (20) rotationally drives the rotating shaft (30), the eccentric movable portion (60) is rotationally driven by the rotating shaft (30). Thereby, the fluid is compressed in the compression mechanism (50). At this time, the speed variation mechanism (70) is configured to vary the rotational speed of the eccentric movable portion (60). By changing the rotational speed of the eccentric movable part (60), the volume change rate of the fluid chamber can be optimized to a desired behavior.

    In a second aspect based on the first aspect, the rotating shaft (30) is configured separately from the first shaft (31) driven by the electric motor (20) and the first shaft (31). An eccentric part (60) that is formed around the second axis (33, 36) so as to be eccentric with the second axis (33, 36) and rotationally drives the eccentric movable part (60). 34), and the speed variation mechanism (70) is configured to vary the rotational speed of the first shaft (31) and transmit it to the second shaft (33, 36).

    In the second invention, the first shaft (31) driven to rotate by the electric motor (20) and the second shaft (33, 36) around which the eccentric portion (34) is formed are configured separately. . When the electric motor (20) rotationally drives the first shaft (31), the speed variation mechanism (70) varies the rotational speed of the first shaft (31) and transmits it to the second shaft (33, 36). As a result, the rotational speed of the eccentric part (34), and hence the rotational speed of the eccentric movable part (60), varies. As a result, the volume change rate of the fluid chamber can be optimized to a desired behavior.

    In a third aspect based on the second aspect, the speed variation mechanism (70) is eccentric with respect to one of the first axis (31) and the second axis (33, 36), and the one axial direction A pin (71) protruding from the end surface, and a groove (72) formed on the other axial end surface of the first shaft (31) and the second shaft (33, 36) and slidably fitted with the pin (71) The axis C1 of the first axis (31) is shifted in a predetermined direction with respect to the axis C3 of the second axis (33, 36).

    In the third invention, the pin (71) is formed on one axial end surface of the first shaft (31) and the second shaft (33, 36), and the groove (72) is formed on the other axial end surface. Is done. When the pin (71) is fitted into the groove (72), the first shaft (31) and the second shaft (33, 36) are engaged. When the first shaft (31) is rotationally driven by the electric motor (20), the pin (71) and the inner wall of the groove (72) come into contact with each other, and the second shaft (33, 36) is rotationally driven. Since the pin (71) is eccentric with respect to the axis C1 of the first shaft (31), the pin (71) rotates eccentrically about the axis C1. At the same time, the pin (71) moves forward and backward in the groove (72). Thereby, when the eccentric movable part (60) rotates once, the distance between the axis C2 of the pin (71) and the axis C3 of the second axis (33, 36) changes. The rotational speed of the eccentric part (34) fluctuates according to the change in distance, and consequently the rotational speed of the eccentric movable part (60) fluctuates.

    When the axis C1 of the first axis (31) is shifted in a predetermined direction with respect to the axis C3 of the second axis (33, 36), the axis C2 of the pin (71) and the second axis in the shifted direction The distance from the axis C3 of (33, 36) becomes longer. For this reason, when the eccentric movable part (60) approaches the direction in which the axis C1 is shifted, the rotational speed of the eccentric movable part (60) increases. On the contrary, when the eccentric movable part (60) approaches the direction opposite to the direction in which the axis C1 is shifted, the rotational speed of the eccentric movable part (60) becomes slow. Thus, according to the direction in which the axis C1 is shifted, the rotational speed of the eccentric movable part (60), and thus the volume change rate of the fluid chamber, can be optimized to a desired behavior.

    In a fourth aspect based on the third aspect, the compression mechanism (50) is formed with a piston (60) that constitutes an eccentric movable portion (60) and a cylinder chamber (55) that accommodates the piston (60). A cylinder (51), a partition member (62) that partitions the cylinder chamber (55) into a low pressure chamber (55a) and a high pressure chamber (55b), a suction port (56) communicating with the low pressure chamber (55a), and a high pressure And a discharge port (57) communicating with the chamber (55b).

    The compression mechanism (50) of 4th invention is comprised by the rotation type which has a piston (60). That is, when the electric motor (20) rotationally drives the first shaft (31), the speed variation mechanism (70) varies the rotational speed of the first shaft (31) and transmits it to the second shaft (33, 36). As a result, the rotational speed of the piston (60) can be optimized during one rotation of the piston (60).

    In a fifth aspect based on the fourth aspect, the axis C1 of the first shaft (31) is located on the top dead center side of the piston (60) with respect to the axis C3 of the second shaft (33, 36). It is characterized by shifting in the direction of.

    In the fifth invention, the axis C1 of the first axis (31) is shifted in the direction toward the top dead center with respect to the axis C3 of the second axis (33, 36). As a result, the rotational speed of the eccentric part (34) or the piston (60) increases near the top dead center, and the rotational speed near the bottom dead center decreases. As a result, in the high pressure chamber (55b) (compression chamber), the volume change rate when the piston (60) passes near the bottom dead center becomes small.

    According to a sixth aspect of the present invention based on the fourth aspect, the axis C1 of the first shaft (31) is in the direction toward the suction port (56) with respect to the shaft center C3 of the second shaft (33, 36). It is characterized by shifting.

    In the sixth invention, the axis C1 of the first shaft (31) is shifted in the direction toward the suction port (56) with respect to the shaft center C3 of the second shaft (33, 36). Thereby, during the discharge stroke in which the fluid is discharged from the discharge port (57), the rotational speed of the eccentric part (34) or the piston (60) becomes slow.

    In a seventh aspect based on the fourth aspect, the shaft center C1 of the first shaft (31) is opposite to the suction port (56) with respect to the shaft center C3 of the second shaft (33, 36). It is characterized by shifting in the direction.

    In the seventh invention, the axis C1 of the first shaft (31) is shifted in the direction opposite to the suction port (56) with respect to the shaft center C3 of the second shaft (33, 36). Thereby, during the suction stroke in which fluid is sucked from the suction port (56), the rotational speed of the eccentric part (34) or the piston (60) is slowed down.

    In an eighth aspect based on any one of the third to seventh aspects, the second shaft (33, 36) extends from the eccentric portion (34) toward the first shaft (31). It has an extending part (33a), and the pin (71) or the groove part (72) is formed on the axial end surface of the extending part (33a).

    The second shaft (33, 36) of the eighth invention is formed with an extending portion (33a) extending from the eccentric portion (34) toward the first shaft (31). A pin (71) or a groove (72) is formed on the end surface in the axial direction of the extension (33a).

    According to the present invention, since the rotational speed of the eccentric movable part (60) can be varied by the speed variation mechanism (70), the volume change rate of the fluid chamber can be optimized. According to the third invention, the speed variation mechanism (70) can be configured with a relatively simple structure. The rotational speed of the eccentric movable part (60) can be optimized according to the direction in which the axis C1 of the first axis (31) is shifted.

    According to the fifth aspect, the volume change rate during one rotation of the piston (60) can be leveled. As a result, the compression torque can be leveled and the motor efficiency can be improved. Further, vibration and noise can be suppressed by reducing the maximum value of the compression torque. In addition, if the rotation speed when the piston (60) passes near the top dead center is increased, the time for the high pressure chamber (55b) or the discharge port (57) to communicate with the suction port (56) is shortened as much as possible. it can. As a result, re-expansion due to this communication can be suppressed, and the volumetric efficiency can be improved. In addition, if the rotation speed when the piston (60) passes near the bottom dead center is slowed, the flow rate of the fluid flowing through the suction port (56) in the suction stroke can be reduced. As a result, the pressure loss of the suction port (56) can be reduced, and the efficiency of illustration can be improved.

    According to the sixth aspect, the flow velocity of the fluid flowing through the discharge port (57) in the discharge stroke can be reduced. As a result, the pressure loss of the discharge port (57) can be reduced, and the efficiency of illustration can be improved.

    According to the seventh aspect, the flow velocity of the fluid flowing through the suction port (56) in the suction stroke can be reduced. As a result, the pressure loss of the suction port (56) can be reduced, and the efficiency of illustration can be improved.

    According to the eighth aspect, since the extending portion (33a) is formed on the second shaft (33, 36), the extending portion (33a) can be supported by the bearing. Thereby, the axial shift of the rotating shaft (30) can be suppressed, and the reliability of the compressor can be improved.

FIG. 1 is a longitudinal sectional view of a compressor according to an embodiment. FIG. 2 is an enlarged longitudinal sectional view of the compression mechanism. FIG. 3 is an exploded perspective view of the rotating shaft. FIG. 4 is an enlarged longitudinal sectional view of the speed variation mechanism. FIG. 5 is a plan view of the compression mechanism in a state where the crank angle is 0 °, and a graph showing the relative positional relationship between the respective axes in this state. FIG. 6 is a plan view of the compression mechanism in a state where the crank angle is 30 °, and a graph showing the relative positional relationship between the respective axes in this state. FIG. 7 is a plan view of the compression mechanism in a state where the crank angle is 60 °, and a graph showing the relative positional relationship between the respective axes in this state. FIG. 8 is a plan view of the compression mechanism in a state where the crank angle is 90 °, and a graph showing the relative positional relationship between the respective axes in this state. FIG. 9 is a plan view of the compression mechanism in a state where the crank angle is 120 ° and a graph showing the relative positional relationship of the respective axes in this state. FIG. 10 is a plan view of the compression mechanism in a state where the crank angle is 150 °, and a graph showing the relative positional relationship between the respective axes in this state. FIG. 11 is a plan view of the compression mechanism in a state where the crank angle is 180 °, and a graph showing the relative positional relationship between the respective axes in this state. FIG. 12 is a plan view of the compression mechanism in a state where the crank angle is 210 °, and a graph showing the relative positional relationship between the respective axes in this state. FIG. 13 is a plan view of the compression mechanism in a state where the crank angle is 240 ° and a graph showing the relative positional relationship between the respective axes in this state. FIG. 14 is a plan view of the compression mechanism in a state where the crank angle is 270 ° and a graph showing the relative positional relationship between the respective axes in this state. FIG. 15 is a plan view of the compression mechanism in a state where the crank angle is 300 °, and a graph showing the relative positional relationship between the respective axes in this state. FIG. 16 is a plan view of the compression mechanism in a state where the crank angle is 330 °, and a graph showing the relative positional relationship between the respective axes in this state. FIG. 17 is a graph showing the relationship between the drive angle and the seal angle in the compressor according to the embodiment. FIG. 18 is a graph showing the relationship between the drive angle and the volume of the compression chamber (high pressure chamber) in the compressor according to the embodiment, and the relationship between the rotation angle and the volume of the compression chamber in the compressor according to the conventional example. FIG. 19 is a graph showing the relationship between the drive angle and the volume change rate of the compression chamber in the compressor according to the embodiment, and the relationship between the rotation angle and the volume change rate of the compression chamber in the compressor according to the conventional example. FIG. 20 is a graph showing the relationship between the drive angle and the compression chamber pressure in the compressor according to the embodiment, and the relationship between the rotation angle and the compression chamber pressure in the compressor according to the conventional example. FIG. 21 is a graph showing the relationship between the drive angle and the compression torque in the compressor according to the embodiment, and the relationship between the rotation angle and the compression torque in the compressor according to the conventional example. FIG. 22 is a diagram corresponding to FIG. 5 according to the first modification. FIG. 23 is a diagram corresponding to FIG. 17 according to the first modification. FIG. 24 is a diagram corresponding to FIG. 5 according to the second modification. FIG. 25 is a diagram corresponding to FIG. 17 according to the second modification. FIG. 26 is an enlarged perspective view of the compression mechanism according to the third modification. FIG. 27 is a diagram corresponding to FIG. 2 according to the third modification.

    Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

<< Embodiment of the Invention >>
<Overall configuration of compressor>
FIG. 1 is a longitudinal sectional view of a compressor (10) according to the present embodiment. The compressor (10) according to the present embodiment is a hermetic rotary compressor. The compressor (10) is connected to a refrigerant circuit (not shown) filled with a refrigerant. In the refrigerant circuit, a vapor compression refrigeration cycle is performed. That is, in the refrigerant circuit, the refrigerant compressed by the compressor (10) is condensed by the condenser, depressurized by the expansion valve, evaporated by the evaporator, and sucked into the compressor (10).

    The compressor (10) includes a casing (11), an electric motor (20) accommodated in the casing (11), a rotating shaft (30) connected to the electric motor (20), and the rotating shaft (30). And a driven compression mechanism (50).

<casing>
The casing (11) is a vertically long cylindrical sealed container. The casing (11) has a trunk (12), a lower end plate (13), and an upper end plate (14). The trunk portion (12) is formed in a cylindrical shape extending vertically, and both ends in the axial direction are open. The lower end plate (13) is fixed to the lower end of the body (12). The upper end plate (14) is fixed to the upper end of the body (12).

    A suction pipe (15) is fixed through the lower portion of the body (12). A discharge pipe (16) passes through and is fixed to the upper end plate (14). A terminal (17) for supplying electric power to the electric motor (20) is attached to the upper end plate (14).

    An oil reservoir (18) is formed at the bottom of the casing (11). The oil reservoir (18) is constituted by the lower end plate (13) and the lower inner wall of the body (12). Lubricating oil (refrigeration machine oil) for lubricating the sliding parts of the compression mechanism (50) and the rotating shaft (30) is stored in the oil storage part (18).

    The inside of the casing (11) is filled with the high-pressure refrigerant compressed by the compression mechanism (50). That is, the compressor (10) is configured as a so-called high-pressure dome type in which the internal pressure of the internal space (S) of the casing (11) is substantially equal to the pressure of the high-pressure refrigerant.

<Electric motor>
The electric motor (20) is disposed above the compression mechanism (50). The electric motor (20) has a stator (21) and a rotor (22). The stator (21) is fixed to the inner peripheral surface of the body (12) of the casing (11). The rotor (22) penetrates the interior of the stator (21) in the vertical direction. A rotating shaft (30) is fixed inside the shaft center of the rotor (22). When the electric motor (20) is energized, the rotating shaft (30) is rotationally driven together with the rotor (22).

<Axis of rotation>
The rotating shaft (30) is located on the axial center of the trunk (12) of the casing (11). The rotating shaft (30) is rotatably supported by each bearing (41, 42, 43) of the compression mechanism (50).

    The rotating shaft (30) is configured by connecting a drive shaft (31) and an eccentric portion (34) that is a separate body from the drive shaft (31). The drive shaft (31) is provided on the upper portion of the rotating shaft (30) and is rotationally driven by the electric motor (20). The drive shaft (31) is formed in an elongated cylindrical shape. The crankshaft (32) is provided below the rotary shaft (30) and rotationally drives the piston (60) of the compression mechanism (50). The crankshaft (32) includes a main shaft (33), a sub shaft (35) continuous to the lower end of the main shaft (33), and an eccentric portion (pin shaft) (34) formed around the lower portion of the main shaft (33). ). Each of the main shaft (33), the sub shaft (35), and the eccentric portion (34) is formed in a cylindrical shape.

    The axis of the main shaft (33) is coincident with the axis of the sub shaft (35). The axis of the eccentric part (34) is eccentric by a predetermined amount with respect to the axis of the main shaft (33). The outer diameter of the main shaft (33) is larger than the outer diameter of the sub shaft (35). The outer diameter of the eccentric part (34) is larger than the outer diameter of the main shaft (33).

    An oil pump (38) is provided at the lower end of the rotating shaft (30). The oil pump (38) conveys the oil accumulated in the oil reservoir (18) to the internal flow path (not shown) of the rotating shaft (30). The oil in the internal flow path is supplied to the sliding mechanism of the compression mechanism (50) and each bearing (41, 42, 43).

<Compression mechanism>
The configuration of the compression mechanism (50) will be described with reference to FIG. 1, FIG. 2, FIG. 5, FIG. The compression mechanism (50) is disposed below the electric motor (20). As shown in FIG. 5 and the like, the compression mechanism (50) is configured as a perfectly circular rocking piston type. The compression mechanism (50) includes a cylinder (51), a front head (52), and a rear head (53). In the compression mechanism (50), the front head (52) is stacked on the upper end (one axial end) of the cylinder (51), and the rear head (53) is disposed on the lower end (other axial end) of the cylinder (51). Laminated. The cylinder (51), the front head (52), and the rear head (53) are integrated via a fastening member (not shown).

    The cylinder (51) is fixed to the inner peripheral surface of the lower portion of the body (12) of the casing (11). The cylinder (51) is formed in a flat and substantially annular shape, and forms a cylindrical cylinder chamber (55) at the center thereof. A suction port (56) extending in the radial direction is formed through the cylinder (51). A suction pipe (15) is connected to the suction port (56) so as to communicate with the cylinder chamber (55).

    An upper through hole (52a) through which the drive shaft (31) and the main shaft (33) pass is formed at the center of the front head (52). A drive bearing (41) that supports the drive shaft (31) is provided on an upper portion of the upper through hole (52a). A main bearing (42) that supports the main shaft (33) is provided at a lower portion of the upper through hole (52a).

    In the front head (52), a discharge port (57) communicating with the high-pressure chamber (55b) of the cylinder chamber (55) is formed penetrating in the axial direction. The discharge port (57) is provided with a discharge valve (not shown) such as a reed valve, for example. When the internal pressure of the high-pressure chamber (55b) exceeds a predetermined value, the discharge valve is opened, and the refrigerant in the high-pressure chamber (55b) flows out of the compression mechanism (50) (inside the internal space (S) of the casing (11)). To do.

    The rear head (53) is disposed below the cylinder (51) so as to cover the internal space of the cylinder (51). A lower through hole (53a) through which the auxiliary shaft (35) passes is formed in the center of the rear head (53).

    The compression mechanism (50) includes a piston (60), a bush (61), and a blade (62). The piston (60) is accommodated in the cylinder chamber (55).

    The piston (60) is formed in a perfect circular cylinder. An eccentric part (34) is fitted in the piston (60). The cross section of the cylinder chamber (55) is formed in a true circle.

    A substantially circular bush groove (63) is formed in the cylinder (51) at a position adjacent to the cylinder chamber (55). A pair of substantially semicircular bushes (61, 61) are fitted in the bush groove (63). The pair of bushes (61, 61) are arranged in the bush groove (63) so that the flat surfaces face each other. The pair of bushes (61, 61) is configured to swing around the axis of the bush groove (63).

    The blade (62) is formed in a rectangular parallelepiped shape or a plate shape extending radially outward. The base end of the blade (62) is connected to the outer peripheral surface of the piston (60). The blade (62) is accommodated in a blade groove (64) formed between the pair of bushes (61, 61) so as to advance and retreat.

    The blade (62) constitutes a partition member that partitions the cylinder chamber (55) into a low pressure chamber (55a) and a high pressure chamber (55b). As shown in FIG. 10 and the like, the low pressure chamber (55a) communicates with the suction port (56), and the high pressure chamber (55b) communicates with the discharge port (57).

<Speed fluctuation mechanism>
The speed variation mechanism and its peripheral structure will be described in detail with reference to FIGS.

    The speed variation mechanism (70) varies the rotational speed of the piston (60) every time the piston (60) makes one rotation in the cylinder chamber (55). The speed variation mechanism (70) has a pin (71) and a groove (72). In this embodiment, a pin (71) is formed on the drive shaft (31) that is the first shaft, and a groove (72) is formed on the main shaft (33) that is the second shaft. A groove (72) may be formed on the drive shaft (31), and a pin (71) may be formed on the main shaft (33).

    The pin (71) is formed on the axial end surface (lower end surface (44)) of the drive shaft (31). The pin (71) is formed in a cylindrical shape and protrudes downward from the lower end surface (44) toward the main shaft (33). The groove (72) is formed on the axial end surface (upper end surface (45)) of the main shaft (33). The groove (72) forms a horizontally long groove that passes through the axis C3 of the main shaft (33). The groove (72) is formed across both ends of the pin (71) in the radial direction. The width of the groove (72) is slightly larger than the outer diameter of the pin (71). The depth of the groove (72) is slightly larger than the height of the pin (71) in the axial direction. The pin (71) is fitted in the groove (72). In the groove (72), the pin (71) is held so as to be slidable in the radial direction of the main shaft (33).

<Relationship between each axis and pin>
As shown in FIGS. 2, 4, 5, etc., the outer diameter of the drive shaft (31) is D1, and the axis of the drive shaft (31) is C1. The outer diameter of the pin (71) is D2, and the axis of the pin (71) is C2. The outer diameter of the main shaft (33) is D3, and the axis of the main shaft (33) (crank shaft (32)) is C3. The outer diameter of the eccentric part (34) is D4, and the axis of the eccentric part (34) is C4. The outer diameter of the auxiliary shaft (35) is D5, and the axis of the auxiliary shaft (35) is C5. In the compressor (10), the relationship of D4>D3>D5>D1> D2 is satisfied.

    In the compressor (10), the shaft center C3 of the main shaft (33) and the shaft center C5 of the sub shaft (35) coincide with each other, and other than that, they are shifted with respect to each other. That is, as shown in FIG. 5 and the like, the axis C2 of the pin (71) is shifted in the radial direction with respect to the axis C1 of the drive shaft (31). The axis C1 of the drive shaft (31) is shifted in the radial direction with respect to the axis C3 of the main shaft (33). The axis C4 of the eccentric portion (34) is shifted in the radial direction with respect to the axis C3 of the main shaft (33).

    In the compressor (10) of this embodiment, the axis C1 is shifted in the direction of top dead center (0 °) with respect to the axis C3. That is, the shaft center C1 is shifted in the direction toward the bush groove (63) with respect to the shaft center C3. In other words, the axis C1 is shifted with respect to the axis C3 in the direction corresponding to 0 ° (360 °) of the seal angle of the piston (60) in the inner peripheral surface of the cylinder (51). Here, the “seal angle” refers to the inner peripheral surfaces of the piston (60) and the cylinder (51) when the piston (60) is located at the top dead center as a reference (seal angle = 0 °). Means the angle of the part that is closest or substantially touching. The amount of eccentricity between the axis C1 of the drive shaft (31) and the axis C2 of the pin (71) is the amount of eccentricity between the axis C1 of the drive shaft (31) and the axis C3 of the main shaft (33). Bigger than.

    In the above configuration, when the electric motor (20) rotationally drives the drive shaft (31) at a constant rotational speed, the speed fluctuation mechanism (70) causes the crankshaft (32) to change the rotational speed of the crankshaft (32). 32) Tell the rotational force to. Thereby, in this embodiment, during one rotation of the piston (60), the rotational speed becomes the fastest when the piston (60) is located near the top dead center, and the piston (60) is located near the bottom dead center. The rotation speed is the slowest (details will be described later).

−Operation of compressor−
The basic operation of the compressor (10) will be described.

    When electric power is supplied from the terminal (17) to the electric motor (20), the electric motor (20) is operated, and the rotating shaft (30) is rotationally driven. Then, the eccentric part (34) of the rotating shaft (30) rotates eccentrically, and the piston (60) rotates eccentrically accordingly.

    As shown in FIGS. 5 to 16, in the compression mechanism (50), the outer peripheral surface of the piston (60) is in line contact with the inner peripheral surface of the cylinder chamber (55) via an oil film to form a seal portion. When the piston (60) swings in the cylinder chamber (55), the seal portion between the piston (60) and the cylinder (51) is displaced along the inner peripheral surface of the cylinder chamber (55). The volume of the low pressure chamber (55a) and the high pressure chamber (55b) changes. At this time, the blade (62) moves back and forth in the blade groove (64) with the swinging motion of the piston (60), and swings about the axis of the bush groove (63).

    When the volume of the low pressure chamber (55a) gradually increases with the swinging motion of the piston (60), the fluid (refrigerant) flowing through the suction pipe (15) is sucked into the low pressure chamber (55a) from the suction port (56). Go. Next, when the low pressure chamber (55a) is blocked from the suction port (56), the blocked space constitutes the high pressure chamber (55b). Next, as the volume of the high pressure chamber (55b) gradually decreases, the internal pressure of the high pressure chamber (55b) increases. When the internal pressure of the high pressure chamber (55b) exceeds a predetermined pressure, the reed valve of the discharge port (57) is opened, and the refrigerant in the high pressure chamber (55b) passes through the discharge port (57) to the outside of the compression mechanism (50). leak. This high-pressure refrigerant flows upward in the internal space of the casing (11) and passes through a core cut (not shown) of the electric motor (20). The high-pressure refrigerant that has flowed out of the electric motor (20) is sent from the discharge pipe (16) to the refrigerant circuit.

<Operation of speed fluctuation mechanism>
Next, the operation of the speed variation mechanism (70) during operation of the compressor (10) will be described with reference to FIGS.

    The speed variation mechanism (70) of the present embodiment increases the rotational speed of the piston (60) (or the crankshaft (32)) when the piston (60) passes near the top dead center, and the piston (60) When passing near the bottom dead center, the rotation speed of the piston (60) (crankshaft (32)) is decreased.

    As shown in FIG. 5, when the piston (60) is at the top dead center, the axis C2 of the pin (71) is dead below the axis C1 of the drive shaft (31) and the axis C3 of the main shaft (33). Shift in the direction of the point (180 °). The line connecting the axis C1 and the axis C2 in the state of FIG. 5 is defined as the reference angle (drive angle = 0 °) of the pin (71), and the drive angle is defined clockwise from the reference angle in FIG. P1 shown in FIG. 5 etc. represents the locus of the axis C2 of the pin (71) when the piston (60) makes one rotation. Each circle on the locus of P2 is obtained by plotting a total of 36 axis C2 of the pin (71) at every drive angle of 10 °. Of these circles, the black circle indicates the position of the axis C2 of the actual pin (71).

    P2 shown in FIG. 5 etc. represents the locus of the axis C4 of the eccentric part (34) when the piston (60) makes one rotation. In the state of FIG. 5, the axis C4 of the eccentric part (34) is shifted in the direction of the top dead center (0 °) from the axis C1 and the axis C3. That is, the shaft center C4 of the eccentric portion (34) is located on the opposite side (180 ° direction) of the shaft center C2 of the pin (71) across the shaft center C3 of the main shaft (33). Each triangular mark on the locus of P1 is obtained by plotting a total of 36 axial centers C4 of the eccentric portion (34) corresponding to each circular mark of the locus P1. Among the triangle marks, the black triangle indicates the position of the axis C4 of the actual eccentric portion (34).

    When the state shown in FIG. 5 is shifted to the state shown in FIG. 6, the axis C2 of the pin (71) advances by 30 ° and the drive angle becomes 30 °. Here, a line segment connecting the axis C2 of the pin (71) and the axis C3 of the main shaft (33) is L1, and a line segment extending from the axis C3 in the opposite direction to the axis C2 and reaching the locus P2 is L2. Then, the axis C4 of the eccentric portion (34) is a position where the line segment L2 contacts the locus P2.

    Here, for example, when shifting from FIG. 5 to FIG. 6, the ratio of the line segment L2 to the line segment L1 (L2 / L1) is relatively large. For this reason, the eccentric angle or movement amount of the eccentric portion (34) when the drive angle advances by 30 ° increases. Therefore, in this state, the rotational speed of the piston (60) is also relatively fast.

    When shifting from the state of FIG. 6 in the order of FIG. 7, FIG. 8, and FIG. 9, the drive angle advances to 90 °, 120 °, and 150 °. As a result, the ratio L2 / L1 of each line segment gradually decreases. Accordingly, the rotational speed of the piston (60) gradually decreases.

    As shown in FIG. 10, when the drive angle reaches 180 °, the ratio L2 / L1 of each line segment becomes minimum. At this time, the piston (60) is located at the bottom dead center. Therefore, in the compression mechanism (50), when the piston (60) passes through the bottom dead center, the rotational speed of the piston (60) is the slowest.

    When the state shown in FIG. 10 is shifted in the order of FIGS. 11, 12, 13, and 14, the drive angle advances to 210 °, 240 °, and 270 °. Along with this, the ratio L2 / L1 of each line segment gradually increases. Accordingly, the rotational speed of the piston (60) gradually increases.

    When shifting from this state in the order of FIGS. 15, 16, and 5, the drive angle advances to 300 °, 330 °, and 360 °, and the ratio L2 / L1 of each line segment further increases. When the drive angle reaches 360 °, the ratio L2 / L1 of each line segment becomes maximum. At this time, the piston (60) is located at the top dead center. Therefore, in the compression mechanism (50), when the piston (60) passes through the top dead center, the rotational speed of the piston (60) becomes the fastest.

<Numerical data during one revolution of piston>
Each numerical data during one rotation of the piston (60) in the compression mechanism (50) of the present embodiment will be described with reference to FIGS. In the graphs shown in FIGS. 17 to 21, each numerical data of the present embodiment is represented by a solid line. In the graphs shown in FIGS. 18 to 21, each numerical value data of the conventional example in which the rotation speed of the piston (60) is constant is represented by a broken line. In FIG. 17 to FIG. 21, the numerical data corresponding to the present embodiment has a horizontal axis in the range of drive angles 0 ° to 360 ° with the state of FIG. 5 (drive angle = 0 °) as a reference. On the other hand, in the graphs of FIGS. 18 to 21, each numerical data corresponding to the conventional example has a rotation angle of 0 ° to 360 ° based on a state where the piston is at the top dead center (rotation angle = 0 °). The range is on the horizontal axis.

    As shown in FIG. 17, in the present embodiment, the change in the seal angle of the piston (60) is rapid when the drive angle is in the range of about 0 ° to about 90 ° and in the range of about 270 ° to about 360 °. . In other words, in the compression mechanism (50), when the drive angle is within these ranges, the rotational speed of the piston (60) increases, and when the drive angle is outside these ranges, the rotational speed of the piston (60). Becomes slower.

    As shown in FIG. 18, the volume of the compression chamber (high pressure chamber (55b)) according to the present embodiment decreases at a substantially constant rate except for the range where the drive angle is around 0 °. On the other hand, the volume of the compression chamber of the conventional example is gradually reduced in the range of the rotation angle of about 0 ° to about 90 ° and in the range of about 270 ° to about 360 °, and the rotation angle is about 90 ° to about 90 °. It becomes steeply smaller in the range of 180 °.

    As shown in FIG. 19, the volume change rate of the compression chamber according to the present embodiment is substantially constant except for the range where the drive angle is around 0 °. On the other hand, the volume change rate of the compression chamber of the conventional example increases sharply when the rotation angle exceeds 0 °, and reaches a peak when the rotation angle is around 180 °. Thereafter, the volume change rate of the compression chamber of the conventional example decreases sharply when the rotation angle exceeds 180 °.

    As shown in FIG. 20, the pressure in the compression chamber according to the present embodiment rises relatively slowly. In contrast, the pressure in the compression chamber of the conventional example rises relatively steeply.

    As shown in FIG. 21, the compression torque of the compression chamber according to the present embodiment is smoothed as compared with the compression torque of the conventional example. In addition, the maximum value of the compression torque of the compression chamber according to the present embodiment is lower than the maximum value of the compression torque of the conventional example.

-Effect of the embodiment-
In the said embodiment, there exist the following effects.

    The speed variation mechanism (70) increases the rotational speed of the piston (60) near the top dead center and slows the rotational speed of the piston (60) near the bottom dead center. As a result, the volume change rate becomes substantially constant when the drive angle is in the range of about 20 ° to about 340 ° (see FIG. 19), and the compression torque can be leveled (see FIG. 20). Thereby, while improving motor efficiency, a vibration and a noise can be suppressed.

    Further, the rotational speed of the piston (60) is increased at the top dead center (see FIG. 17), whereby the time during which the high pressure chamber (55b) or the discharge port (57) communicates with the suction port (56) (for example, The period of the state of FIG. 5 can be shortened as much as possible. As a result, re-expansion due to this communication can be suppressed, and the volumetric efficiency can be improved. In addition, if the rotation speed when the piston (60) passes near the bottom dead center is slowed, the flow rate of the fluid flowing through the suction port (56) in the suction stroke can be reduced. As a result, the pressure loss of the suction port (56) can be reduced, and the efficiency of illustration can be improved.

    The speed variation mechanism (70) is simply formed by forming the pin (71) on the drive shaft (31) and the groove (72) on the main shaft (33) of the crankshaft (32). Can be easily varied.

    By forming the groove (72) in the main shaft (33) of the crankshaft (32), the speed variation mechanism (70) can be configured while the main shaft (33) is supported by the main bearing (42). For this reason, the shift | offset | difference of the shaft center of a rotating shaft (30) can be suppressed reliably, and the reliability of a compressor (10) can be improved.

<< Modification of Embodiment >>
The above embodiment may be modified as follows.

<Modification 1>
As shown in FIG. 22, in the first modification, the relative eccentric direction between the axis C1 of the drive shaft (31) and the axis C3 of the main shaft (33) is different from the above embodiment. Specifically, in the above embodiment, the axis C1 is shifted to the top dead center side of the piston (60) with respect to the axis C3. On the other hand, in the first modification, the axis C1 is shifted to the suction port (56) side with respect to the axis C3. Strictly speaking, the axis C1 is shifted in the direction of the seal angle 90 ° of the piston (60) with respect to the axis C3.

    In Modification 1, as shown in FIG. 23, the rotational speed of the piston (60) until the drive angle reaches about 180 ° to about 360 ° can be reduced. Therefore, the flow velocity of the fluid flowing through the discharge port (57) in the discharge stroke can be reduced. As a result, the pressure loss of the discharge port (57) can be reduced, and the efficiency of illustration can be improved.

<Modification 2>
As shown in FIG. 24, in the second modification, the relative eccentric direction between the axis C1 of the drive shaft (31) and the axis C3 of the main shaft (33) is different from the above embodiment. Specifically, in the second modification, the axis C1 is shifted to the opposite side of the suction port (56) with respect to the axis C3. Strictly speaking, the axis C1 is shifted in the direction of the seal angle 270 ° of the piston (60) with respect to the axis C3.

    In the second modification, as shown in FIG. 25, the rotational speed of the piston (60) until the drive angle reaches about 0 ° to about 180 ° can be reduced. Therefore, the flow velocity of the fluid flowing through the suction port (56) in the suction stroke can be reduced. As a result, the pressure loss of the suction port (56) can be reduced, and the efficiency of illustration can be improved.

<Modification 3>
As shown in FIGS. 26 and 27, the third modification differs from the above embodiment in the structure of the crankshaft (32) and the front head (52).

    Specifically, the crankshaft (32) of Modification 3 is omitted from the main shaft (33) of the above embodiment. The crankshaft (32) has an intermediate shaft (36), an eccentric part (34) formed around the intermediate shaft (36), and a countershaft (35). The entire intermediate shaft (36) is located inside the eccentric portion (34). A drive bearing (41) that supports the drive shaft (31) is formed inside the upper through hole (52a) of the front head (52) of Modification 3. On the other hand, the main bearing (42) of the above embodiment is omitted inside the upper through hole (52a).

    A groove (72) is formed in the upper end surface (46) of the intermediate shaft (36). A pin (71) protruding from the lower end surface (44) of the drive shaft (31) is fitted into the groove (72). A pin (71) may be formed on the upper end surface (46) of the intermediate shaft (36), and a groove (72) may be formed on the lower end surface (44) of the drive shaft (31).

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

    The compression mechanism (50) of the above embodiment is a perfectly circular rocking piston type. However, the compression mechanism (50) may be a non-circular swinging piston type or a rolling piston type having vanes as partition members. The compression mechanism (50) may be of a scroll type having a movable scroll that is an eccentric movable portion and a fixed scroll.

    Further, the speed variation mechanism (70) may shift the axis C1 with respect to the axis C3 in a direction other than the above embodiment (for example, the direction of the bottom dead center), for example.

    As described above, the present invention is useful for a compressor.

C1 Drive shaft axis C3 Main shaft axis, intermediate shaft axis 10 Compressor 20 Electric motor 30 Rotating shaft 31 Drive shaft (first shaft)
33 Spindle (second axis)
33a Extension portion 34 Eccentric portion 36 Intermediate shaft (second shaft)
50 compression mechanism 51 cylinder 55 cylinder chamber 55a low pressure chamber 55b high pressure chamber 56 suction port 57 discharge port 60 piston (eccentric movable part)
62 Blade (partition member)
70 Speed variation mechanism 71 Pin 72 Groove

Claims (8)

A compressor,
An electric motor (20),
A rotating shaft (30) driven to rotate by the electric motor (20);
An eccentric movable part (60) that is rotationally driven by the rotary shaft (30), and a compression mechanism (50) that compresses fluid;
The compressor characterized in that the rotating shaft (30) has a speed fluctuation mechanism (70) that fluctuates the rotational speed of the eccentric movable part (60). In claim 1,
The rotating shaft (30)
A first shaft (31) driven to rotate by the electric motor (20);
A second shaft (33, 36) configured separately from the first shaft (31);
An eccentric portion (34) formed around the second shaft (33, 36) so as to be eccentric with the second shaft (33, 36) and rotating the eccentric movable portion (60);
The compressor characterized in that the speed variation mechanism (70) is configured to vary the rotational speed of the first shaft (31) and transmit it to the second shaft (33, 36). In claim 2,
The speed fluctuation mechanism (70)
A pin (71) that is eccentric with one of the first shaft (31) and the second shaft (33, 36) and protrudes from the one axial end surface;
A groove portion (72) formed on the other axial end surface of the first shaft (31) and the second shaft (33, 36) and slidably fitted with the pin (71),
The compressor characterized in that an axis C1 of the first shaft (31) is shifted in a predetermined direction with respect to an axis C3 of the second shaft (33, 36). In claim 3,
The compression mechanism (50)
A piston (60) constituting the eccentric movable part (60);
A cylinder (51) in which a cylinder chamber (55) for accommodating the piston (60) is formed;
A partition member (62) for partitioning the cylinder chamber (55) into a low pressure chamber (55a) and a high pressure chamber (55b);
A suction port (56) communicating with the low pressure chamber (55a);
And a discharge port (57) communicating with the high pressure chamber (55b). In claim 4,
The axis C1 of the first shaft (31) is shifted in the direction toward the top dead center of the piston (60) with respect to the axis C3 of the second shaft (33, 36). Compressor. In claim 4,
The compressor characterized in that an axis C1 of the first shaft (31) is shifted in a direction toward the suction port (56) with respect to an axis C3 of the second shaft (33, 36). In claim 4,
The axis C1 of the first shaft (31) is shifted in a direction opposite to the suction port (56) with respect to the shaft center C3 of the second shaft (33, 36). Machine. In any one of Claims 3 thru | or 7,
The second shaft (33, 36) has an extending portion (33a) extending from the eccentric portion (34) toward the first shaft (31),
The compressor according to claim 1, wherein the pin (71) or the groove (72) is formed on an end surface in the axial direction of the extending portion (33a).

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