JP7424260B2 - rotary compressor - Google Patents

Description

The present invention relates to a rotary compressor.

In the compression part of a rotary compressor, a piston fitted into an eccentric part of a rotating shaft rotates along the inner peripheral surface of the cylinder to form a cylinder chamber inside the cylinder, and moves along the vane groove of the cylinder. A structure is known in which the tip of the vane and the outer peripheral surface of the piston are in contact and the cylinder chamber is divided into a suction chamber and a compression chamber. In such a compression section, the piston fitted into the rotating shaft rotates around the rotating shaft while revolving along the inner circumferential surface of the cylinder as the rotating shaft rotates.

International Publication No. 2018/131265

In the compression section as described above, as the revolution speed of the piston becomes slower, the piston tends to become more difficult to rotate. For this reason, when the rotating shaft rotates at a low speed where the revolution speed of the piston is slow, there is a possibility that the rotational movement of the piston in the circumferential direction of the eccentric portion of the rotating shaft may stop. If the piston only revolves without rotating, the tip of the vane will come into contact with only a portion of the outer circumference of the piston in the circumferential direction, causing abnormal wear on a portion of the piston. Put it away. If such abnormal wear occurs, the piston may be deformed and the compression section may stop abnormally.

The disclosed technology has been made in view of the above, and provides a rotary compressor that promotes the rotational movement of the piston in the circumferential direction of the eccentric part when the rotating shaft rotates at low speed, and can suppress abnormal wear of the piston. With the goal.

One aspect of the rotary compressor disclosed in the present application includes a compressor housing provided with a refrigerant discharge part and a suction part, and a compressor housing arranged inside the compressor housing to compress and discharge refrigerant sucked from the suction part. A compression section that discharges air from the compressor, and a motor disposed within the compressor housing to drive the compression section.The compression section includes an annular cylinder, an upper end plate and a lower end plate that close the cylinder, an upper end plate A rotating shaft supported by the lower end plate and rotated by a motor, an eccentric part provided eccentrically with respect to the center of the rotating shaft, and a cylinder chamber that is fitted into the eccentric part and rotates along the inner peripheral surface of the cylinder. In a rotary compressor, the rotary compressor has a piston that forms a suction chamber and a vane that protrudes into the cylinder chamber from a vane groove provided in the cylinder and comes into contact with the piston to divide the cylinder chamber into a suction chamber and a compression chamber. A coating film that increases the frictional force between the outer circumferential surface and the inner circumferential surface of the piston is formed on a part of the outer circumferential surface in the circumferential direction, and the coating film increases in the circumferential direction of the outer circumferential surface of the eccentric part. , a first position where the direction in which the center of the eccentric part is eccentric with respect to the center of the rotating shaft intersects the outer peripheral surface of the eccentric part, and a central angle around the center of the eccentric part from this first position in the rotational direction of the rotating shaft. is formed only within the range between the second position and the second position, which forms an angle of 90 degrees.

According to one aspect of the rotary compressor disclosed in the present application, when the rotary shaft rotates at low speed, the piston is encouraged to rotate in the circumferential direction of the eccentric portion, thereby suppressing abnormal wear of the piston.

FIG. 1 is a longitudinal sectional view showing a rotary compressor according to an embodiment. FIG. 2 is an exploded perspective view showing the compression section of the rotary compressor of the embodiment. FIG. 3 is a plan view for explaining the main parts of the rotary compressor of the embodiment. FIG. 4 is an enlarged plan view showing the upper eccentric part of the rotating shaft in the embodiment. FIG. 5A is a side view showing an example of a pattern of a coating film formed on the upper eccentric portion of the rotating shaft in the example. FIG. 5B is a side view showing another example of the pattern of the coating film formed on the upper eccentric part of the rotating shaft in the example. FIG. 5C is a side view showing another example of the pattern of the coating film formed on the upper eccentric portion of the rotating shaft in the example. FIG. 6 is a diagram for explaining the behavior of the upper eccentric portion and the upper piston when the coating film is formed in the range from 0 degrees to 180 degrees in the reference example. FIG. 7 is a diagram for explaining the behavior of the upper eccentric part and the upper piston when the coating film is formed in the range from 0 degrees to 90 degrees in the example. FIG. 8 is a diagram for explaining the behavior of the upper eccentric part and the upper piston when the coating film is formed in the range from 0 degrees to 45 degrees in the example.

Embodiments of the rotary compressor disclosed in the present application will be described in detail below based on the drawings. Note that the rotary compressor disclosed in the present application is not limited to the following examples.

(Configuration of rotary compressor)
FIG. 1 is a longitudinal sectional view showing a rotary compressor according to an embodiment. FIG. 2 is an exploded perspective view showing the compression section of the rotary compressor of the embodiment.

As shown in FIG. 1, the rotary compressor 1 includes a compression section 12 disposed at the lower part of the compressor housing 10 in the form of a vertically placed vertical cylinder, and a compression section 12 disposed at the upper part of the compressor housing 10. It includes a motor 11 that drives the compression section 12 via a rotating shaft 15, and a vertically placed cylindrical accumulator 25 fixed to the outer peripheral surface of the compressor housing 10.

The accumulator 25 is connected to the upper cylinder chamber 130T (see FIG. 2) of the upper cylinder 121T via the upper suction pipe 105 and the accumulator upper curved pipe 31T, and is connected to the lower cylinder 121S via the lower suction pipe 104 and the accumulator lower curved pipe 31S. It is connected to the lower cylinder chamber 130S (see FIG. 2).

The motor 11 includes a stator 111 placed on the outside and a rotor 112 placed on the inside. The stator 111 is fixed to the inner circumferential surface of the compressor housing 10 in a shrink-fitted state, and the rotor 112 is fixed to the rotating shaft 15 in a shrink-fitted state.

In the rotating shaft 15, a lower sub-shaft part 151 of a lower eccentric part 152S is rotatably supported by a sub-bearing part 161S provided on a lower end plate 160S, and a main shaft part 153 above an upper eccentric part 152T is supported by an upper end plate 160S. It is rotatably supported by a main bearing part 161T provided at 160T. The rotating shaft 15 has an annular upper piston 125T and an annular lower piston 125S supported by an upper eccentric part 152T and a lower eccentric part 152S, which are provided with a phase difference of 180 degrees from each other. Thereby, the rotating shaft 15 is rotatably supported with respect to the compression part 12, and as it rotates, the upper piston 125T and the lower piston 125S are moved to the inner peripheral surface 137T of the upper cylinder 121T and the inner peripheral surface Each is caused to revolve along the surface 137S.

Further, the inner circumferential surface 125a of the upper piston 125T is in contact with the outer circumferential surface 152a of the upper eccentric portion 152T of the rotating shaft 15, and the upper piston 125T rotates along the circumferential direction of the inner surface of the upper cylinder 121T, and the upper eccentric The portion 152T rotates along the circumferential direction. The inner circumferential surface 125a of the lower piston 125S is in contact with the outer circumferential surface 152a of the lower eccentric part 152S, and the lower piston 125S rotates in the circumferential direction of the lower eccentric part 152S while orbiting along the circumferential direction of the inner surface of the lower cylinder 121S. Performs rotational motion along the axis. In this embodiment, a coating film 155 that increases the coefficient of friction is formed on a portion of the outer peripheral surface 152a of the upper eccentric portion 152T and a portion of the outer peripheral surface 152a of the lower eccentric portion 152S (see FIG. 1). . Details of the coating film 155 will be described later.

Inside the compressor housing 10, lubricating oil (refrigerating machine oil) 18 to be supplied to the compression section 12 is stored. Inside the compressor housing 10, lubricity of sliding parts such as an upper piston 125T and a lower piston 125S that slide in the compression part 12 is ensured, and an upper compression chamber 133T (see FIG. 2) and a lower compression chamber 133S are provided. (See FIG. 2), lubricating oil 18 is sealed in an amount that substantially immerses the compressed portion 12. Attachment legs 310 (see FIG. 1) that lock a plurality of elastic support members (not shown) that support the entire rotary compressor 1 are fixed to the lower side of the compressor housing 10.

As shown in FIG. 1, in the compressor housing 10, a discharge pipe 107 for discharging refrigerant is provided in the upper part 10b, and an upper suction pipe 105 and a lower suction pipe 104 for sucking the refrigerant are provided in the side part. ing. The compression unit 12 compresses the refrigerant sucked in from the upper suction pipe 105 and the lower suction pipe 104, and discharges it from the discharge pipe 107 to a refrigerant circuit (not shown). As shown in FIG. 2, the compression part 12 includes, from above, an upper end plate cover 170T having a bulging part with a hollow space formed inside, an upper end plate 160T, an annular upper cylinder 121T, an intermediate partition plate 140, an annular upper cylinder 121T, an annular upper cylinder 121T, an annular upper cylinder 121T, an annular It is constructed by laminating a lower cylinder 121S, a lower end plate 160S, and a flat lower end plate cover 170S. The entire compression part 12 is fixed by a plurality of through bolts 174, 175 and an auxiliary bolt 176 arranged substantially concentrically from above and below.

As shown in FIG. 2, the upper cylinder 121T has a cylindrical inner peripheral surface 137T. An upper piston 125T with an outer diameter smaller than the inner diameter of the inner circumferential surface 137 of the upper cylinder 121T is disposed inside the inner circumferential surface 137T of the upper cylinder 121T, and the inner circumferential surface 137T and the outer circumferential surface 139T of the upper piston 125T An upper compression chamber 133T is formed between the upper compression chamber 133T and the upper compression chamber 133T, which sucks in refrigerant, compresses it, and discharges it. A cylindrical inner circumferential surface 137S is formed in the lower cylinder 121S. A lower piston 125S with an outer diameter smaller than the inner diameter of the inner circumferential surface 137S of the lower cylinder 121S is disposed inside the inner circumferential surface 137S of the lower cylinder 121S, and the inner circumferential surface 137S and the outer circumferential surface 139S of the lower piston 125S A lower compression chamber 133S is formed between the refrigerant and the refrigerant.

The upper cylinder 121T has an upper side protrusion 122T extending from the circular outer circumferential portion in the radial direction of the cylindrical inner circumferential surface 137T. The upper side protrusion 122T is provided with an upper vane groove 128T that extends radially outward from the upper cylinder chamber 130T. An upper vane 127T is slidably disposed within the upper vane groove 128T. The lower cylinder 121S has a lower side protrusion 122S that protrudes from the circular outer circumferential portion in the radial direction of the cylindrical inner circumferential surface 137S. The lower side protrusion 122S is provided with a lower vane groove 128S that extends radially outward from the lower cylinder chamber 130S. A lower vane 127S is slidably disposed within the lower vane groove 128S.

The upper cylinder 121T is provided with an upper spring hole 124T at a position that overlaps with the upper vane groove 128T from the outer surface and has a depth that does not penetrate into the upper cylinder chamber 130T. An upper spring 126T is arranged in the upper spring hole 124T. A lower spring hole 124S is provided in the lower cylinder 121S at a position that overlaps with the lower vane groove 128S from the outer surface and has a depth that does not penetrate into the lower cylinder chamber 130S. A lower spring 126S is arranged in the lower spring hole 124S.

In addition, the lower cylinder 121S communicates the radially outer side of the lower vane groove 128S with the inside of the compressor housing 10 through an opening to introduce the compressed refrigerant inside the compressor housing 10 to the lower vane 127S. A lower pressure introduction path 129S is formed to apply back pressure based on the pressure of the refrigerant. Note that the compressed refrigerant in the compressor housing 10 is also introduced from the lower spring hole 124S. Further, in the upper cylinder 121T, the radially outer side of the upper vane groove 128T and the inside of the compressor housing 10 are communicated through an opening to introduce the compressed refrigerant inside the compressor housing 10 to the upper vane 127T. An upper pressure introduction path 129T is formed to apply back pressure based on the pressure of the refrigerant. Note that the compressed refrigerant in the compressor housing 10 is also introduced from the upper spring hole 124T.

An upper suction hole 135T into which the upper suction pipe 105 is fitted is provided in the upper side protrusion 122T of the upper cylinder 121T. A lower suction hole 135S into which the lower suction pipe 104 is fitted is provided in the lower protrusion 122S of the lower cylinder 121S.

The upper cylinder chamber 130T is closed at the top and bottom by an upper end plate 160T and an intermediate partition plate 140, respectively. The lower cylinder chamber 130S is closed at the top and bottom by an intermediate partition plate 140 and a lower end plate 160S, respectively.

The upper cylinder chamber 130T is formed in the upper suction chamber 131T, which communicates with the upper suction hole 135T, and the upper end plate 160T, by the upper vane 127T being pressed by the upper spring 126T and coming into contact with the outer peripheral surface 139T of the upper piston 125T. It is divided into an upper compression chamber 133T communicating with the upper discharge hole 190T (see FIG. 3). The lower cylinder chamber 130S is formed in a lower suction chamber 131S that communicates with the lower suction hole 135S and a lower end plate 160S by the lower vane 127S being pressed by the lower spring 126S and coming into contact with the outer peripheral surface 139S of the lower piston 125S. It is divided into a lower compression chamber 133S communicating with the lower discharge hole 190S (see FIG. 3).

As shown in FIG. 2, the upper end plate 160T is provided with an upper discharge hole 190T that passes through the upper end plate 160T and communicates with the upper compression chamber 133T of the upper cylinder 121T. An upper valve seat (not shown) is formed around the discharge hole 190T. The upper end plate 160T is formed with an upper discharge valve accommodating recess 164T that extends in a groove shape from the position of the upper discharge hole 190T in the circumferential direction of the upper end plate 160T.

The upper discharge valve housing recess 164T has a reed valve type upper discharge valve 200T whose rear end is fixed in the upper discharge valve housing recess 164T by an upper rivet 202T and whose front part opens and closes the upper discharge hole 190T, and a rear end thereof. The entire upper discharge valve holder 201T is stacked on the upper discharge valve 200T and fixed in the upper discharge valve accommodation recess 164T by an upper rivet 202T, and has a curved (warped) front part and regulates the opening degree of the upper discharge valve 200T. It is accommodated.

The lower end plate 160S is provided with a lower discharge hole 190S that passes through the lower end plate 160S and communicates with the lower compression chamber 133S of the lower cylinder 121S. A lower discharge valve accommodating recess (not shown) is formed in the lower end plate 160S and extends in a groove shape from the position of the lower discharge hole 190S in the circumferential direction of the lower end plate 160S.

The lower discharge valve housing recess includes a reed valve type lower discharge valve 200S whose rear end is fixed in the lower discharge valve housing recess by a lower rivet 202S and whose front part opens and closes the lower discharge hole 190S, and a lower discharge valve 200S whose rear end is a lower discharge valve. The entire lower discharge valve holder 201S, which is stacked on the valve 200S and fixed by a lower rivet 202S in the lower discharge valve housing recess and has a curved (warped) front part and regulates the opening degree of the lower discharge valve 200S, is accommodated. There is.

An upper end plate cover chamber 180T is formed between the upper end plate 160T, which is closely fixed to each other, and the upper end plate cover 170T, which has a bulging portion. A lower end plate cover chamber 180S (see FIG. 1) is formed between the lower end plate 160S and the flat lower end plate cover 170S, which are closely fixed to each other. A refrigerant passage hole 136 is provided that passes through the lower end plate 160S, the lower cylinder 121S, the intermediate partition plate 140, the upper end plate 160T, and the upper cylinder 121T and communicates the lower end plate cover chamber 180S and the upper end plate cover chamber 180T.

The flow of the refrigerant due to the rotation of the rotating shaft 15 will be explained below. In the upper cylinder chamber 130T, as the rotation shaft 15 rotates, the upper piston 125T fitted on the upper eccentric portion 152T of the rotation shaft 15 is brought into contact with the inner peripheral surface 137T of the upper cylinder 121T (the outer peripheral surface of the upper cylinder chamber 130T). As the upper suction chamber 131T expands its volume and sucks refrigerant from the upper suction pipe 105, the upper compression chamber 133T compresses the refrigerant while decreasing its volume, and the pressure of the compressed refrigerant is discharged upward. When the pressure becomes higher than the pressure in the upper end plate cover chamber 180T outside the valve 200T, the upper discharge valve 200T opens and the refrigerant is discharged from the upper compression chamber 133T to the upper end plate cover chamber 180T. The refrigerant discharged into the upper end plate cover chamber 180T is discharged into the compressor housing 10 from an upper end plate cover discharge hole 172T (see FIG. 1) provided in the upper end plate cover 170T.

In addition, in the lower cylinder chamber 130S, due to the rotation of the rotary shaft 15, the lower piston 125S fitted to the lower eccentric portion 152S of the rotary shaft 15 moves to the inner circumferential surface 137S of the lower cylinder 121S (the outer circumferential surface of the lower cylinder chamber 130S). ), the lower suction chamber 131S sucks refrigerant from the lower suction pipe 104 while expanding its volume, and the lower compression chamber 133S compresses the refrigerant while decreasing its volume, and the pressure of the compressed refrigerant increases. When the pressure becomes higher than the pressure in the lower end plate cover chamber 180S outside the lower discharge valve 200S, the lower discharge valve 200S opens and the refrigerant is discharged from the lower compression chamber 133S to the lower end plate cover chamber 180S. The refrigerant discharged into the lower end plate cover chamber 180S passes through the refrigerant passage hole 136 and the upper end plate cover chamber 180T, and is discharged into the compressor housing 10 from the upper end plate cover discharge hole 172T provided in the upper end plate cover 170T. .

The refrigerant discharged into the compressor housing 10 is discharged through a notch (not shown) provided along the vertical direction on the outer periphery of the stator 111, or a gap (not shown) in the winding part of the stator 111. Alternatively, the refrigerant is guided above the motor 11 through the gap 115 between the stator 111 and the rotor 112 (see FIG. 1), or through the refrigerant passage (not shown) inside the rotor 112, and is disposed in the upper part 10b of the compressor housing 10. The liquid is discharged from the discharge pipe 107.

(Characteristic configuration of rotary compressor)
Next, a characteristic configuration of the rotary compressor 1 according to the embodiment will be described. The features of the embodiment include a coating film 155 formed at a predetermined position that is a part of the outer circumferential surface 152a of the upper eccentric part 152T of the rotating shaft 15 and a predetermined position that is a part of the outer circumferential surface 152a of the lower eccentric part 152S. is included.

Hereinafter, the coating film 155 formed on the upper eccentric part 152T will be explained, and the explanation of the coating film 155 formed on the lower eccentric part 152S will be omitted. A coating film 155 is formed. The same applies to the effect of the coating film 155 on the upper eccentric portion 152T and the lower eccentric portion 152S.

As described above, the upper piston 125T rotates along the circumferential direction of the upper eccentric portion 152T of the rotating shaft 15 while revolving along the circumferential direction of the inner surface of the upper cylinder 121T. As the speed decreases, the upper piston 125T tends to become difficult to rotate. Therefore, when the rotating shaft 15 rotates at a low speed, the upper piston 125T may not rotate in the circumferential direction of the upper eccentric portion 152T of the rotating shaft 15, and the rotational movement of the upper piston 125T may stop. In order to prevent the rotational movement from stopping due to the upper piston 125T becoming difficult to rotate, a coating film 155 is formed on a part of the outer circumferential surface 152a of the upper eccentric portion 152T in this embodiment.

FIG. 3 is a plan view for explaining the main parts of the rotary compressor 1 of the embodiment. FIG. 4 is an enlarged plan view showing the upper eccentric portion 152T of the rotating shaft 15 in the embodiment. In FIGS. 3 and 4, the rotating shaft 15 rotates along the clockwise arrow direction, and the upper piston 125T revolves and rotates.

As shown in FIGS. 3 and 4, the outer circumferential surface 152a of the upper eccentric portion 152T of the rotating shaft 15 in this embodiment has a structure that increases the frictional force between the outer circumferential surface 152a and the inner circumferential surface 125a of the upper piston 125T. A coating film 155 is formed on a portion of the outer circumferential surface 152a in the circumferential direction. That is, on the outer circumferential surface 152a of the upper eccentric portion 152T, the friction coefficient in the area where the coating film 155 is formed is higher than the friction coefficient in the area where the coating film 155 is not formed.

With such a coating film 155, at a predetermined timing in the revolution movement of the upper piston 125T when the rotating shaft 15 rotates at a low speed, the gap between the outer circumferential surface 152a of the upper eccentric portion 152T and the inner circumferential surface 125a of the upper piston 125T is By increasing the frictional force, the rotational motion of the upper piston 125T is prevented from stopping.

Specifically, in the circumferential direction of the outer peripheral surface 152a of the upper eccentric part 152T, the coating film 155 has a center C2 of the upper eccentric part 152T eccentric with respect to a center C1 of the rotating shaft 15, as shown in FIG. A first position P1 where the direction intersects the outer circumferential surface 152a, and a second position P2 where the central angle θ around the center C2 of the upper eccentric portion 152T forms 90 degrees from this first position P1 in the rotational direction of the rotating shaft 15. It is formed only within the range between

The first position P1 of the outer peripheral surface 152a of the upper eccentric part 152T is located on the straight line L connecting the center C1 of the rotating shaft 15 and the center C2 of the upper eccentric part 152T, and is Let the central angle θ around the center C2 be 0 degrees. Hereinafter, regarding the range in which the coating film 155 is formed, as shown in FIG. Also called degree.

The coating film 155 formed between the first position P1 and the second position P2 is, for example, formed continuously in the circumferential direction on the outer circumferential surface 152a of the upper eccentric portion 152T. They may be formed discontinuously at intervals.

In addition, in this embodiment, the coating film 155 formed between the first position P1 and the second position P2 is arranged as shown in FIG. 4, it may be formed only within the range between the first position P1 and the third position P3 where the central angle θ around the center C2 of the upper eccentric portion 152T is 45 degrees (see FIG. 8). ). Note that the coating film 155 has a central angle θ around the center C2 of at least 10 degrees on the outer circumferential surface 152a of the upper eccentric portion 152T in order to appropriately increase the frictional force between the upper piston 125T and the upper eccentric portion 152T. It is desirable that it be formed over the same range.

As the coating film 155, for example, a silicone thin film is used. Since the silicone thin film has a heat resistance temperature of about 200 [° C.], durability against the internal temperature of the compression section 12 can be ensured. The thickness of the coating film 155 is preferably about several [μm]. When the thickness of the coating film 155 is thicker than several [μm], a desired gap (for example, This is not preferable because it becomes difficult to secure a gap of 20 [μm] or more, and the ease of assembling and operational reliability of the compression section 12 deteriorates. Further, if the thickness of the coating film 155 is thinner than several [μm], it is not preferable because it becomes difficult to control the thickness of the coating film 155.

As described in the subject, in the compression section 12, as the revolution speed of the upper piston 125T becomes slower, the upper piston 125T tends to become more difficult to rotate. For this reason, when the rotating shaft 15 rotates at a low speed where the revolution speed of the upper piston 125T becomes slow, there is a possibility that the rotational movement of the upper piston 125T with respect to the circumferential direction of the upper eccentric portion 152T of the rotating shaft 15 may stop. Therefore, as described above, the coating film 155 is formed between the first position P1 (0 degrees) and the second position P2 (90 degrees) in the circumferential direction of the outer peripheral surface 152a of the upper eccentric part 152T. When the upper piston 125T rotates at a low speed, the frictional force between the upper piston 125T and the upper eccentric portion 152T is increased at a predetermined timing in the revolution movement. This promotes the rotational movement of the upper piston 125T, thereby preventing the rotational movement from stopping and suppressing abnormal wear of the upper piston 125T.

The reason why the frictional force between the upper piston 125T and the upper eccentric part 152T is increased intermittently at a predetermined timing in the revolution movement of the upper piston 125T is that the coating film 155 is in the first position P1 (0 degree) and in the second position. The reason for forming the gap with P2 (90 degrees) will be described later (FIGS. 6 to 8).

Generally, the Sommerfeld number S, which represents the lubrication state of a sliding bearing by the lubricating oil 18, is S = ηn/ Represented by P. The larger the Sommerfeld number S, the better the lubrication state, and the larger the rotational speed n, the better the lubrication state. Therefore, when the rotating shaft 15 rotates at a high speed, an oil film is likely to be formed on the sliding surface.

Therefore, when the rotating shaft 15 rotates at a low speed, an oil film of the lubricating oil 18 is hardly formed between the outer circumferential surface 152a of the upper eccentric portion 152T of the rotating shaft 15 and the inner circumferential surface 125a of the upper piston 125T. Therefore, the outer peripheral surface 152a of the upper eccentric part 152T and the inner peripheral surface 125a of the upper piston 125T tend to come into direct contact, and the frictional force generated by the coating film 155 formed on the upper eccentric part 152T is impaired by the oil film. This effectively acts to rotate the upper piston 125T with respect to the upper eccentric portion 152T without causing the upper eccentric portion 152T to rotate.

On the other hand, when the rotating shaft 15 rotates at high speed, an oil film of the lubricating oil 18 is likely to be formed between the outer circumferential surface 152a of the upper eccentric portion 152T of the rotating shaft 15 and the inner circumferential surface 125a of the upper piston 125T. Therefore, the outer peripheral surface 152a of the upper eccentric part 152T and the inner peripheral surface 125a of the upper piston 125T do not come into contact with each other through the oil film, so no friction force is generated by the coating film 155 formed on the upper eccentric part 152T, and the The covering film 155 does not provide rotational resistance to the upper piston 125T with respect to the upper eccentric portion 152T. In this way, the coating film 155 promotes the rotational movement of the upper piston 125T when the rotational shaft 15 rotates at a low speed, and does not hinder the rotational movement of the upper piston 125T when the rotational shaft 15 rotates at a high speed.

FIG. 5A is a side view showing an example of the pattern of the coating film 155 formed on the upper eccentric portion 152T of the rotating shaft 15 in the example. 5B and 5C are side views showing other examples of patterns of the coating film 155 formed on the upper eccentric portion 152T of the rotating shaft 15 in the embodiment.

As shown in FIG. 5A, the coating film 155 formed on the outer circumferential surface 152a of the upper eccentric portion 152T is continuous with the upper and lower ends of the outer circumferential surface 152a in the axial direction (vertical direction) of the rotating shaft 15, for example. It is formed. The coating film 155 is not limited to being formed continuously in the axial direction of the rotating shaft 15 on the outer circumferential surface 152a of the upper eccentric portion 152T, but may be formed at intervals in the axial direction of the rotating shaft 15. It's fine.

For example, as shown in FIG. 5B, the coating film 155 may be formed only at the center of the outer circumferential surface 152a in the axial direction of the rotating shaft 15, or as shown in FIG. They may be formed on the upper end side and the lower end side of the outer circumferential surface 152a except for the center. This makes it possible to appropriately adjust the magnitude of the frictional force generated by the coating film 155 and to reduce the manufacturing cost required for forming the coating film 155.

(Range of formation of coating film)
The range in the circumferential direction of the outer circumferential surface 152a of the upper eccentric portion 152T in which the coating film 155 is formed will be described with reference to FIGS. 6 to 8 showing the revolution movement of the upper piston 125T.

6 to 8, the rotating shaft 15 rotates clockwise as shown by the arrow, and the upper piston 125T rotates while the upper piston 125T revolves clockwise along the inner peripheral surface 137T of the upper cylinder 121T. It rotates around axis 15. In addition, in FIGS. 6 to 8, the rotation angle of the rotation shaft 15 around the center C1 (referred to as the rotation angle of the upper piston 125T) is from 0 degrees to 360 degrees clockwise with reference to the orbital movement of the upper piston 125T. (0 degrees), the state changes sequentially every 45 degrees. The rotation angle of the upper piston 125T is set to 0 degrees when the upper piston 125T pushes the upper vane 127T the most into the upper vane groove 128T.

At the top dead center where the rotation angle of the upper piston 125T is 0 degrees, the first position P1 of the outer peripheral surface 152a of the upper eccentric portion 152T (the central angle θ around the center C2 of the upper eccentric portion 152T is 0 degrees) is the upper piston. It is located on a straight line L connecting the center C1 of the rotating shaft 15 and the position where the upper vane 125T and the upper vane 127T touch. As the rotation angle of the upper piston 125T that revolves changes, the position of the first position P1 of the upper eccentric portion 152T matches the rotation angle of the upper piston 125T with respect to the circumferential direction of the inner peripheral surface of the upper cylinder 121T. Move like this. That is, at the bottom dead center where the rotation angle of the upper piston 125T is 180 degrees, the first position P1 of the outer peripheral surface 152a of the upper eccentric portion 152T moves to a position of 180 degrees in the circumferential direction of the upper cylinder 121T.

For example, as shown in FIG. 6, in the upper cylinder 121T, when the upper piston 125T revolves, the contact position between the upper piston 125T and the upper vane 127T changes as the rotation angle of the upper piston 125T changes. , the sizes of the upper suction chamber 131T and the upper compression chamber 133T in the upper cylinder 121T change. When the rotation angle of the upper piston 125T is 0 degrees, the upper suction chamber 131T is just before shifting to the upper compression chamber 133T, and the upper compression chamber 133T is at a position where the volume is reduced to zero. As the rotation angle of the upper piston 125T increases from 0 degrees, the upper suction chamber 131T gradually becomes larger and the upper compression chamber 133T gradually becomes smaller.

In the upper cylinder 121T, when the refrigerant is compressed in the upper compression chamber 133T, the pressure in the upper compression chamber 133T (discharge pressure) becomes greater than the pressure in the upper suction chamber 131T (suction pressure), and the discharge The differential pressure between the pressure and the suction pressure acts on the outer peripheral surface 139T of the upper piston 125T. Due to this differential pressure, the outer circumferential surface 139T of the upper piston 125T forming the inside of the upper compression chamber 133T is moved toward the upper suction chamber 131T in the direction in which the differential pressure acts (direction F indicated by a diagonal arrow in the figure). Being pushed.

Additionally, this differential pressure is caused by changes in the position where the upper piston 125T and the upper vane 127T contact, and the position where the outer peripheral surface 139T of the upper piston 125T and the inner peripheral surface 137T of the upper cylinder 121T contact, that is, the volume of the upper compression chamber 133T. Along with the change, the direction in the direction of arrow F in which the differential pressure acts and the magnitude of the differential pressure change. In other words, as the rotation angle of the upper piston 125T increases, the differential pressure gradually increases and the direction in the direction of the arrow F in which the differential pressure acts changes.

Due to the generation of the differential pressure in this way, the position It will be pushed in the direction. Further, the position X of the inner peripheral surface 125a of the upper piston 125T moves along the circumferential direction of the inner peripheral surface 125a of the upper piston 125T as the rotation angle of the upper piston 125T changes.

In this embodiment, the position X of the inner circumferential surface 125a of the upper piston 125T pressed by the outer circumferential surface 152a of the upper eccentric portion 152T overlaps with the formation range of the coating film 155 on the outer circumferential surface 152a of the upper eccentric portion 152T. At this timing, the coating film 155 increases the frictional force generated between the upper piston 125T and the upper eccentric portion 152T.

Based on the behavior of such differential pressure, first, the formation range of the coating film 155 in the reference example will be explained. FIG. 6 shows the upper eccentricity when the coating film 155 is formed in the range from 0 degrees to 180 degrees with reference to the central angle θ (see FIG. 4) around the center C2 of the upper eccentric portion 152T in a reference example. It is a figure for explaining the behavior of part 152T and upper piston 125T.

As shown in FIG. 6, the coating film 155 extends between the first position P1 (0 degree) and the second position P2 (90 degrees) on the outer circumferential surface 152a of the upper eccentric portion 152T, and extends from 0 degrees to 180 degrees. When the position X of the inner circumferential surface 125a of the upper piston 125T that is pressed against the outer circumferential surface 152a of the upper eccentric portion 152T due to the differential pressure acting in the direction of the arrow F is one rotation of the upper piston 125T. During the orbital movement of , it always overlaps with the formation range of the coating film 155 .

Therefore, during one revolution of the upper piston 125T, the frictional force between the upper piston 125T and the upper eccentric portion 152T is constantly increased at the position X by the coating film 155. As a result, the rotational load on the rotating shaft 15 on which the upper piston 125T rotates together with the upper eccentric portion 152T increases, which causes an increase in loss of driving force of the motor 11. Therefore, in order to efficiently drive the compression section 12 by the motor 11, it is necessary to make the formation range of the coating film 155 narrower than the range from 0 degrees to 180 degrees.

FIG. 7 shows the upper eccentricity when the coating film 155 is formed in the range from 0 degrees to 90 degrees with reference to the central angle θ (see FIG. 4) around the center C2 of the upper eccentric portion 152T in the embodiment. It is a figure for explaining the behavior of part 152T and upper piston 125T. FIG. 8 shows the upper eccentric part 152T and the upper piston in the case where the coating film 155 is formed in the range from 0 degrees to 45 degrees with reference to the central angle θ around the center C2 of the upper eccentric part 152T. 125 is a diagram for explaining the behavior of 125T.

As shown in FIG. 7, when the coating film 155 is formed in the range from the first position P1 (0 degrees) to the second position P2 (90 degrees) on the outer peripheral surface 152a of the upper eccentric part 152T, the upper piston Until 125T reaches the top dead center (0 degrees) and the bottom dead center (180 degrees), the inside of the upper piston 125T is pressed against the outer circumferential surface 152a of the upper eccentric portion 152T by the differential pressure acting in the direction of arrow F. The position X of the circumferential surface 125a does not overlap the coating film 155, and the coating film 155 does not provide a large frictional force.

Then, when the upper piston 125T reaches the bottom dead center (180 degrees), the position The frictional force between the portion 152T and the portion 152T is increased. Thereafter, the frictional force between the upper piston 125T and the upper eccentric portion 152T is increased by the coating film 155 until just before the upper piston 125T reaches the top dead center (360 degrees) from the bottom dead center (180 degrees).

In this way, the magnitude of the differential pressure acting in the direction of arrow F changes during one revolution of the upper piston 125T, but the upper piston 125T has a relatively large differential pressure during the revolution. The inner circumferential surface 125a of the upper piston 125T is pressed against the coating film 155 of the upper eccentric portion 152T due to a large pressure difference between the bottom dead center (180 degrees) and the top dead center (360 degrees). Accordingly, the frictional force between the upper piston 125T and the upper eccentric portion 152T can be increased. Therefore, the frictional force generated by the coating film 155 promotes the rotation of the upper piston 125T together with the upper eccentric portion 152T, so that the upper eccentric portion 152T rotates the upper piston 125T, thereby controlling the rotational movement of the upper piston 125T. Stoppages are suppressed.

Further, by forming the coating film 155 only in the above-mentioned formation range, the rotational resistance of the inner circumferential surface 125a of the upper piston 125T with respect to the outer circumferential surface 152a of the upper eccentric portion 152T is suppressed from becoming too large. As a result, while the upper piston 125T performs an autorotational motion in which it rotates together with the upper eccentric portion 152T at the above-mentioned predetermined timing during one revolution of the revolution movement of the upper piston 125T, the inner circumferential surface 125a of the upper piston 125T rotates at a timing other than the predetermined timing. As the outer circumferential surface 152a of the upper eccentric portion 152T slides against the upper piston 152T, the rotational movement of the upper piston 125T is performed intermittently, and an increase in the rotational load on the rotating shaft 15 that rotates the upper piston 152T can be suppressed. .

Further, as shown in FIG. 8, when the coating film 155 is formed in the range from the first position P1 (0 degrees) to the third position P3 (45 degrees) on the outer peripheral surface 152a of the upper eccentric part 152T, Until the upper piston 125T reaches 270 degrees from the top dead center (0 degrees), the inner peripheral surface 125a of the upper piston 125T is pressed against the outer peripheral surface 152a of the upper eccentric portion 152T by the differential pressure acting in the direction of arrow F. The position X does not overlap the coating film 155, and the coating film 155 does not provide a large frictional force.

Then, when the upper piston 125T reaches 270 degrees, the position The frictional force is increased. Thereafter, the frictional force between the upper piston 125T and the upper eccentric portion 152T is increased by the coating film 155 from 270 degrees until just before the upper piston 125T reaches the top dead center (360 degrees). That is, in the latter half of the compression process of the refrigerant in the upper compression chamber 133T, just before the refrigerant in the upper compression chamber 133T is discharged from the upper discharge hole 190T, the frictional force between the upper piston 125T and the upper eccentric portion 152T increases. be enhanced.

In this way, by increasing the frictional force between the upper piston 125T and the upper eccentric portion 152T at the timing when the differential pressure acting in the direction of the arrow F1 becomes significantly large during one revolution of the upper piston 125T, , the rotational resistance of the upper piston 125T rotating with respect to the upper eccentric portion 152T is further suppressed from becoming too large.

(Effects of Example)
As described above, the outer circumferential surface 152a of the upper eccentric portion 152T (lower eccentric portion 152S) of the rotating shaft 15 in the rotary compressor 1 of the embodiment has an outer circumferential surface and an inner circumferential surface 125a of the upper piston 125T (lower piston 125S). A coating film 155 that increases the frictional force between the two is formed on a portion of the outer peripheral surface 152a in the circumferential direction. In the circumferential direction of the outer peripheral surface 152a of the upper eccentric part 152T (lower eccentric part 152S), the coating film 155 has a center C2 of the upper eccentric part 152T (lower eccentric part 152S) eccentric with respect to the center C1 of the rotating shaft 15. The central angle θ around the center C2 of the upper eccentric portion 152T (lower eccentric portion 152S) is 90 from the first position P1 where the direction intersects the outer peripheral surface 152a and from this first position P1 toward the rotation direction of the rotating shaft 15. It is formed only within the range between the second position P2 and the second position P2. As a result, at a predetermined timing during the revolution of the upper piston 125T (lower piston 125S), the coating film 155 reduces the frictional force between the upper piston 125T and the upper eccentric portion 152T (lower piston 125S and lower eccentric portion 152S). It is possible to increase it. Therefore, when the rotating shaft 15 rotates at low speed, the upper piston 125T (lower piston 125S) rotates together with the upper eccentric part 152T (lower eccentric part 152S) in the circumferential direction of the upper eccentric part 152T (lower eccentric part 152S). Since the movement can be encouraged, the rotational movement of the upper piston 125T (lower piston 125S) can be prevented from stopping. As a result, the upper vane 127T (lower vane 127S) prevents the compression section 12 from stopping abnormally due to deformation of the outer shape of the upper piston 125T (125S) caused by abnormal wear of the upper piston 125T (lower piston 125S).

Further, in the rotary compressor 1 of the embodiment, in the circumferential direction of the outer peripheral surface 152a of the upper eccentric part 152T (lower eccentric part 152S), the coating film 155 is located at the first position P1 and at the upper eccentric part 152T (lower eccentric part 152S) and the third position P3 where the central angle θ is 45 degrees. As a result, in the latter half of the refrigerant compression process, just before the refrigerant in the upper compression chamber 133T (lower compression chamber 133S) is discharged from the upper discharge hole 190T, the upper piston 125T and the upper eccentric part 152T (the lower piston 125S and the lower eccentric 152S) is increased. Therefore, during one revolution of the upper piston 125T (lower piston 125S), the force that presses the upper piston 125T against the upper eccentric part 152T (the force that presses the lower piston 125S against the lower eccentric part 152S) becomes significantly large. The frictional force between the upper piston 125T and the upper eccentric part 152T (lower piston 125S and the lower eccentric part 152S) can be increased at the timing when the upper piston 125T (lower eccentric part 152S) rotates with respect to the upper eccentric part 152T. It is further suppressed that the rotational resistance of the lower piston 125S) that rotates against the lower piston 125S becomes too large.

Further, the coating films 155 in the rotary compressor 1 of the embodiment are formed at intervals in the circumferential direction of the outer peripheral surface 152a of the upper eccentric portion 152T (lower eccentric portion 152S). This makes it possible to appropriately adjust the magnitude of the frictional force generated by the coating film 155 and to reduce the manufacturing cost required for forming the coating film 155.

Further, the coating film 155 of the rotary compressor 1 of the embodiment is formed at intervals in the axial direction of the rotating shaft 15 on the outer peripheral surface 152a of the upper eccentric part 152T (lower eccentric part 152S). This makes it possible to appropriately adjust the magnitude of the frictional force generated by the coating film 155 and to reduce the manufacturing cost required for forming the coating film 155.

(Modified example)
In the embodiment described above, the single coating film 155 was formed on the upper eccentric portion 152T of the rotating shaft 15, but the coating film 155 was formed at the first position P1 (0 degrees) and the second position P2 on the outer circumferential surface 152a of the upper eccentric portion 152T. (90 degrees) or between the first position P1 (0 degrees) and the third position P3 (45 degrees), the coating film 155 extends along the circumferential direction of the outer peripheral surface of the upper eccentric portion 152T. It may include a plurality of types of coating films 155 having different coefficients of friction arranged side by side.

In this case, a plurality of types of coating films 155 may be formed such that the coefficient of friction increases as the central angle θ at the upper eccentric portion 152T increases from the first position P1. By forming a plurality of types of coating films 155 on the upper eccentric part 152T, the pressing force generated at the position X where the upper piston 125T is pressed against the upper eccentric part 152T is distributed along the circumferential direction of the upper eccentric part 152T. It becomes possible to generate an appropriate frictional force between the upper piston 125T and the upper eccentric portion 152T depending on the magnitude of the change. Further, as the plurality of types of coating films 155, for example, in the circumferential direction of the outer peripheral surface 152a of the upper eccentric portion 152T, a second coating film is formed in a predetermined range on the first coating film formed on the outer peripheral surface 152a. may be formed by laminating some of them.

Note that although the embodiment was applied to a so-called two-cylinder rotary compressor 1 that includes an upper cylinder 121T and a lower cylinder 121S, it may also be applied to a so-called one-cylinder rotary compressor that has one cylinder. good.

1 Rotary compressor 10 Compressor housing 11 Motor 12 Compression section 104 Lower suction pipe (suction section)
105 Upper suction pipe (suction part)
107 Discharge pipe (discharge part)
121T Upper cylinder 121S Lower cylinder 125T Upper piston 125S Lower piston 125a Inner peripheral surface 127T Upper vane 127S Lower vane 128T Upper vane groove 128S Lower vane groove 130T Upper cylinder chamber 130S Lower cylinder chamber 131T Upper suction chamber 131S Lower suction chamber 133T upper compression chamber 133S Lower compression chamber 152T Upper eccentric part 152S Lower eccentric part 152a Outer peripheral surface 155 Coating film 160T Upper end plate 160S Lower end plate P1 1st position P2 2nd position P3 3rd position C1 Center of rotating shaft C2 Center of eccentric part L Straight line θ center angle

Claims (5)

a compressor housing provided with a refrigerant discharge part and a suction part; a compression part disposed inside the compressor housing to compress the refrigerant sucked from the suction part and discharge it from the discharge part; a motor disposed within a compressor housing and driving the compression section;
The compression section is
an annular cylinder;
an upper end plate and a lower end plate that close the cylinder;
a rotating shaft supported by the upper end plate and the lower end plate and rotated by the motor;
an eccentric part provided eccentrically with respect to the center of the rotating shaft;
a piston that is fitted into the eccentric portion and rotates along the inner circumferential surface of the cylinder to form a cylinder chamber within the cylinder;
a vane that protrudes into the cylinder chamber from a vane groove provided in the cylinder and comes into contact with the piston to divide the cylinder chamber into a suction chamber and a compression chamber;
In a rotary compressor having
A coating film that increases the frictional force between the outer circumferential surface and the inner circumferential surface of the piston is formed on a part of the outer circumferential surface of the eccentric part in the circumferential direction,
In the circumferential direction of the outer circumferential surface of the eccentric part, the coating film is arranged at a first position where a direction in which the center of the eccentric part is eccentric with respect to the center of the rotating shaft intersects with the outer circumferential surface; The rotary compressor is formed only within a range between the position and a second position where a central angle around the center of the eccentric portion forms 90 degrees in the direction of rotation of the rotary shaft. In the circumferential direction of the outer circumferential surface of the eccentric part, the coating film is formed only within a range between the first position and a third position where the central angle is 45 degrees.
The rotary compressor according to claim 1. The coating film includes a plurality of types of coating films having different coefficients of friction arranged in a line along the circumferential direction of the outer peripheral surface of the eccentric part.
The rotary compressor according to claim 1 or 2. The coating film is formed at intervals in a circumferential direction of the outer peripheral surface of the eccentric part,
A rotary compressor according to any one of claims 1 to 3. The coating film is formed on the outer circumferential surface of the eccentric portion at intervals in the axial direction of the rotating shaft.
A rotary compressor according to any one of claims 1 to 4.

Images