JP5864883B2 - Scroll compressor - Google Patents

Description

  The present invention relates to a scroll compressor used for an air conditioner, a refrigerator, and the like.

  In general, a scroll compressor employs a structure in which a sliding bearing is attached to a frame and slides on the thrust surface of the orbiting scroll in order to prevent the thrust surface of the orbiting scroll from being worn or seized (for example, patents). Reference 1).

  Hereinafter, the structure of the conventional thrust bearing described in Patent Document 1 will be described. The thrust bearing is composed of a plain bearing with a steel backing, such as an aluminum alloy or a lead bronze alloy, and is attached to the frame with rivets. The thrust bearing has a ring shape, and a plurality of oil grooves are provided at equal intervals radially from the inner peripheral side to the outer peripheral side on the sliding surface, ie, the upper surface, with the bottom surface of the orbiting scroll. . The cross-sectional shape of the oil groove is substantially rectangular, and the corners are chamfered so as to form a curved surface, and a sag portion is provided in an R shape so that oil can easily spread over the entire sliding surface.

  The conventional thrust bearings described above are effective in preventing wear and seizure of the thrust surface, but they are attached to the frame with rivets, so the number of parts increases, and the processing of oil grooves and sliding rivet holes in the slide bearings increases. It was difficult to process and increased costs.

  On the other hand, it is conceivable that the thrust bearing is not provided, and the orbiting scroll itself is made of a slidable aluminum alloy or the like, and the bottom surface of the base plate is a thrust bearing. However, in this case, since the linear expansion coefficient of the aluminum alloy rocking scroll is different from that of the cast iron fixed scroll, if the temperature of the compression section rises during the operation of the compressor, the fixed scroll and the rocking scroll There is a problem that a gap is generated between the two and refrigerant gas leaks.

  Furthermore, it is conceivable that both the fixed scroll and the swing scroll are made of an aluminum alloy. However, in this case, since the strength is weaker than that of cast iron, the tooth thickness of the spiral must be increased, and the wire Since the expansion coefficient is large, the operable temperature range is narrowed. Therefore, it is difficult to configure both the fixed scroll and the swing scroll with an aluminum alloy.

Japanese Patent Publication No. 6-105079

  The present invention has been made to solve the above-described problems. A first object of the present invention is to obtain a thrust bearing that slides in a sufficiently lubricated state with a low-resource and low-cost structure. That is.

  A second object is to obtain a scroll compressor in which the orbiting scroll can be made of the same material as that of the fixed scroll, and no leakage gap is generated due to the temperature rise of the compression section.

In order to achieve the above object, a scroll compressor according to the present invention comprises a fixed scroll provided on an upper part in a hermetic shell and formed with spiral teeth on a base plate, and a compression unit together with the fixed scroll, The upper end is an orbiting scroll having a spiral tooth formed on the base plate and having a boss portion having an oscillating bearing at the center of the bottom surface, and an eccentric shaft portion rotatably engaged with the oscillating bearing via a slider. The main shaft is rotated by an electric motor, has a bottomed cylindrical shape, the outer periphery is fixed to the inner peripheral surface of the shell, and the base plate of the fixed scroll is applied to the upper end surface of the open side with the orbiting scroll interposed therebetween. In a scroll compressor having a main bearing on which a main shaft is rotatably supported at a bottom portion, a ring-shaped thrust plate is disposed between the swing scroll and the bottom portion of the frame. Is And a thrust face ring of the outer peripheral side projecting below the bottom surface of the base plate of the orbiting scroll is formed, constitutes a thrust bearing portion in the thrust plate and the thrust surface, a portion of the outer periphery of the ring-like thrust plate A brim portion is formed, and the brim portion is accommodated in a suction port formed in the frame .

  The thrust bearing portion of the present invention has a simple structure in which a ring-shaped thrust plate disposed between the swing scroll and the frame slides directly with a ring-shaped thrust surface provided on the bottom surface of the swing scroll. The structure is adopted. Due to the revolving motion of the orbiting scroll, there is always an area where the thrust surface protrudes from the thrust plate, and the protruding surface is exposed to a space filled with oil and then slides against the thrust plate again.

  By repeating this operation the same number of times as the number of rotations, the thrust surface of the orbiting scroll and the thrust plate are slid in a lubricated state. As a result, it is not necessary to attach a slide bearing or the like to the bottom surface of the orbiting scroll, and a thrust bearing portion having a simple structure with low resources and low cost can be obtained.

  In addition, since the orbiting scroll can be made of cast iron made of the same material as the fixed scroll, even if the temperature of the compression section rises and thermally expands during the operation of the compressor, there is a leak gap between the fixed scroll and the orbiting scroll. Does not occur.

It is a longitudinal cross-sectional view of the scroll compressor concerning Embodiment 1 of this invention. It is a principal part expanded sectional view of the compression part of the scroll compressor of FIG. It is a principal part expanded sectional view explaining the function of the seal | sticker shown in FIG. It is a principal part expanded sectional view of the thrust bearing part of the scroll compressor of FIG. It is a cross-sectional view of the thrust bearing part in Embodiment 1 of this invention. It is a figure which shows the positional relationship of the thrust surface of an orbiting scroll, and a thrust plate. It is a principal part expanded sectional view of the thrust bearing part in Embodiment 2 of this invention.

Embodiment 1 FIG.
In this invention, a ring-shaped thrust surface formed on the back surface of the base plate of the orbiting scroll that revolves and a ring-shaped thrust plate disposed between the orbiting scroll and the bottom of the frame slide. Thus, a thrust bearing portion is configured. The thrust plate is a component for adjusting the distance from the tip of the orbiting scroll to the base plate of the fixed scroll and the distance from the tooth tip of the fixed scroll to the base plate of the orbiting scroll (that is, the tooth tip gap). However, this is utilized as a thrust bearing that supports the orbiting scroll in the axial direction. Hereinafter, a scroll compressor according to the present invention will be described with reference to the drawings.

  FIG. 1 is a longitudinal sectional view of a scroll compressor 1 according to a first embodiment of the present invention. In FIG. 1, a fixed scroll 2 and an orbiting scroll 3, which are main members of the compressor, are disposed in an upper portion of a hermetic shell 9. Further, a stator 4 and a rotor 5 constituting an electric mechanism section are disposed in an intermediate portion in the shell 9, the stator 4 is fixed to the inner peripheral surface of the shell 9, and the rotor 5 is fixed to the main shaft 6. Has been.

  The compression unit includes a fixed scroll 2, a swing scroll 3, and a frame 12. The fixed scroll 2 has a spiral tooth 2b formed on the lower surface of the base plate 2a and is disposed on the upper side, and the orbiting scroll 3 has a spiral tooth 3b formed on the upper surface of the base plate 3a and is disposed on the lower side. Has been.

  The spiral teeth 2b of the fixed scroll 2 and the spiral teeth 3b of the orbiting scroll 3 have substantially the same shape, and are combined so that the centers of the respective spirals are eccentric and are 180 degrees out of phase with each other. Yes. A compression chamber 17 whose volume changes relatively is formed between the spiral teeth 2 a of the fixed scroll 2 and the spiral teeth 3 a of the swing scroll 3.

  The base plate 2a of the fixed scroll 2 is fixed to the open end (upper end) of the bottomed cylindrical frame 12 whose upper end is opened with a bolt or the like. A discharge port 20 is formed at the center of the fixed scroll 2 to discharge the compressed and high-pressure refrigerant gas.

  A rocking bearing 3d is formed on the boss portion 3c provided near the center of the bottom surface of the rocking scroll 3. A slider 7 is rotatably inserted into the oscillating bearing 3d, and an eccentric shaft portion 8 provided at the upper end of the main shaft 6 is inserted into a slit formed near the center of the slider 7. The inner peripheral part of the rocking bearing 3d and the outer peripheral part of the slider 7 are in close contact with each other through the lubricating oil to constitute the rocking bearing part. The boss portion 3c of the orbiting scroll 3 is pivotally supported by the eccentric shaft portion 8 via an orbiting bearing portion, and the main shaft 6 is pivoted to the frame 12 via a main bearing 12b formed on the bottom portion 12a of the frame 12. It is supported.

  The outer periphery of the frame 12 is fixed to the inner peripheral surface of the shell 9. In addition, a space for accommodating the Oldham ring 14 is formed at the center of the upper surface of the bottom 12 a of the frame 12. The orbiting scroll 3 performs a revolving orbiting motion (oscillating motion) without rotating about the fixed scroll 2 by an Oldham ring 14 for preventing the rotating motion. At this time, the centrifugal force accompanying the eccentric rotational movement of the orbiting scroll 3 acts on the eccentric shaft portion 8.

  A suction pipe 10 for introducing refrigerant gas from the outside and a discharge pipe 11 for discharging refrigerant gas to the outside are attached to a part of the shell 9. A sub frame 21 that rotatably supports the main shaft 6 is fixed to the lower portion of the shell 9. A positive displacement oil pump 13 that sucks oil accumulated at the bottom of the shell 9 to the slider 7 through an oil supply passage in the main shaft 6 is provided below the subframe 21. A pump shaft that transmits rotational force to the oil pump 13 is formed integrally with the main shaft 6.

  FIG. 2 shows a part of the fixed scroll 2 and the swing scroll 3 in FIG. There is a gap δ between the tip surface of the spiral tooth 3b of the orbiting scroll 3 and the base plate 2a of the fixed scroll 2, and between the tip surface of the spiral tooth 2b of the fixed scroll 2 and the base plate 3a of the orbiting scroll 3. Just away. A groove 3e is formed on the tip surface of the spiral tooth 3b of the swing scroll 3, and a seal 18 is disposed in the groove 3e. Similarly, a groove 2c is formed on the tip surface of the spiral tooth 2b of the fixed scroll 2, and a seal 19 is disposed in the groove 2c. These seals 18 and 19 are provided in order to reduce refrigerant leakage from the tip surfaces of the spiral teeth 2b and 3b.

  The function of the seals 18 and 19 will be described with reference to FIG. FIG. 3 shows the load applied to the tip of the spiral tooth 3b of the orbiting scroll 3 and the seal 18 by the gas pressure of the refrigerant gas, and the direction and length of the arrow indicate the direction and magnitude of the load. .

  In the scroll compressor, there are a plurality of compression chambers 17 formed by spirals simultaneously, and the inner compression chamber has a higher pressure. As shown in FIG. 3, the seal 18 inserted in the groove 3e on the tip surface of the spiral tooth 3b of the orbiting scroll 3 is a fixed scroll due to the pressure difference between the compression chamber inside the compressed refrigerant gas and the compression chamber outside. 2 is pressed against the base plate 2a. By this function, it is possible to prevent the refrigerant gas from leaking from the inner compression chamber to the outer compression chamber via the tip surface of the spiral tooth 3b.

  In addition, the seal 19 fitted in the groove 2c on the front end surface of the spiral tooth 2b of the fixed scroll 2 also has the same principle as that of the seal 18 at the end of the base plate 3a of the orbiting scroll 3 and the end of the spiral tooth 2b of the fixed scroll 2. By being pressed against the inner wall of the groove 2c, refrigerant leakage from the spiral tooth tip can be prevented.

  Returning to the description of FIG. 1, a thrust plate 15 that supports the swing scroll 3 is disposed between the base plate 3 a of the swing scroll 3 and the bottom 12 a of the frame 12. A thrust bearing portion is configured by bringing the thrust surface formed on the bottom surface of the base plate 3a into close contact with the thrust plate 15 via lubricating oil. The structure of the thrust bearing portion will be described in detail later with reference to the drawings.

  The drive unit includes a stator 4 fixed to the inner peripheral side of the shell 9, a rotor 5 fixed to the main shaft 6, a main shaft 6 that is a rotating shaft, and the like. The rotor 5 is rotationally driven by starting energization of the stator 4 to rotate the main shaft 6. That is, the stator 4 and the rotor 5 constitute an electric mechanism unit. The main shaft 6 rotates with the rotation of the rotor 5 and causes the orbiting scroll 3 to turn.

  Next, the operation of the scroll compressor 1 will be described. When a power supply terminal (not shown) is energized, torque is generated between the stator 4 and the rotor 5, and the main shaft 6 rotates. Thereby, the orbiting scroll 3 fixed to the slider 7 attached to the eccentric shaft portion 8 of the main shaft 6 starts revolving motion.

  Refrigerant gas that has entered the compression section from the suction pipe 10 through the suction port 12c in the frame 12 is taken into the compression chamber 17 formed by the fixed scroll 2 and the swing scroll 3 and is compressed to a high pressure. When this gas pressure pushes the tooth bottom surface and the tooth tip surface of the orbiting scroll 3 downward, a downward thrust load is generated on the base plate 3a of the orbiting scroll 3, and this thrust load is all generated in the thrust bearing portion. Will bear.

  The refrigerant gas compressed in the compression chamber 17 passes through the discharge port 20 and is discharged into the discharge space 24, and then is discharged out of the shell 9 through the discharge pipe 11.

  Next, the flow of the lubricating oil will be described. The lubricating oil that accumulates at the bottom of the shell 9 and is sucked by the oil pump 13 is conveyed upward through an oil hole or the like formed in the main shaft 6 and lubricates the rocking bearing portion, and then the bottom 12a of the frame 12 is lubricated. Of the sliding space inside the frame 12, that is, the Oldham ring 14 and the frame 12, the Oldham ring 14 and the orbiting scroll 3, the thrust plate 15 and the frame 12, and the thrust plate 15 and the orbiting scroll 3. Lubricate the sliding portion of the thrust surface 3e.

  After that, a part of the oil is taken into the compression chamber 17 together with the refrigerant and used for sliding lubrication between the spiral teeth 2b of the fixed scroll 2 and the spiral teeth 3b of the orbiting scroll 3. Passes through the oil drain hole 22 and is returned to the bottom of the shell 9 again. Therefore, the lower space of the base plate 3a of the swing scroll 3 in the frame 12 is filled with oil during operation.

  Next, with reference to FIG. 4 and FIG. 5, the structure of a thrust bearing part is demonstrated. 4 is an enlarged cross-sectional view of the main part of the thrust bearing portion shown in FIG. 1, and FIG. 5 is a cross-sectional view of the frame 12 cut in a direction perpendicular to the axis O. In FIG. 5, members disposed in the hollow portion of the thrust plate 15 such as the Oldham ring 14 are omitted in order to avoid complication.

  As shown in FIG. 4, a thrust plate 15 formed of a ring-shaped metal plate is disposed on the outer peripheral side of the bottom portion 12 a of the bottomed cylindrical frame 12. In addition, a ring-shaped thrust surface 3f protruding slightly downward is formed on the outer peripheral side of the bottom surface of the base plate 3a of the orbiting scroll 3. A thrust bearing portion is constituted by the thrust surface 3 f formed on the bottom surface of the base plate 3 a and the thrust plate 15.

  As shown in FIG. 5, the outer diameter of the thrust plate 15 is substantially equal to the inner diameter of the cylindrical portion of the bottomed cylindrical frame 12. The inner diameter of the thrust plate 15 needs to be a size that does not hinder the movement of the Oldham ring 14 disposed in the hollow portion. A flange portion 16 is formed on a part of the outer periphery of the thrust plate 15, and the flange portion 16 is disposed so as to be accommodated in the suction port 12 a in which the frame 12 is formed. Even if the thrust plate 15 tries to rotate around the axis O during operation of the compressor 1, the flange portion 16 comes into contact with the flange of the suction port 12a to prevent rotation. For this reason, the thrust plate 15 does not rotate during operation.

  FIG. 6 is a view showing a positional relationship between the ring-shaped thrust surface 3 f of the orbiting scroll 3 and the thrust plate 15. The thrust plate 15 is a ring-shaped plate made of a hard steel plate such as valve steel and has a thickness of about 0.5 mm. Although the outer diameter of the ring-shaped thrust surface 3 f is smaller than the outer diameter of the thrust plate 15, the radial width L is substantially equal to the width of the thrust plate 15.

  In the figure, 0 is the axis of the shell 9, and the center of the thrust plate 15 is arranged at the axis 0 of the shell 9. On the other hand, 0 'is the center of the base plate 3a of the swing scroll 3. Since the orbiting scroll 3 revolves around the axis 0 with an eccentricity of the crank radius r, there is a portion where the thrust surface 3f of the orbiting scroll 3 protrudes inside the thrust plate 15, and the protrusion distance of the protruding portion is The maximum value R is always constant. In the present embodiment, the maximum value R of the protruding distance is, for example, about 40%.

  In FIG. 4, the space below the base plate 3a of the orbiting scroll 3 is filled with oil, whereas the space on the upper and side surfaces of the base plate 3a has an oil ratio of 0.3% or more in the refrigerant. Inhalation gas atmosphere. The lower part of the base plate 3a is slightly higher than the suction gas pressure at the upper part of the base plate 3a by the positive displacement oil pump 13, but is higher than the pump pressure.

  As shown in FIG. 6, a part of the thrust surface 3f always protrudes from the thrust plate 15 by the revolving motion of the orbiting scroll 3, and the protruding surface is exposed to a space filled with oil, and then slides on the thrust plate 15 again. Move. Since the pressure at the lower part of the base plate 3a is larger than the pressure at the upper part of the base plate 3a, the protruding portion of the thrust surface 3f repeats sliding with the thrust plate 15 again, so that the base plate 3a is lowered from the lower part of the base plate 3a. Oil flows to the upper part of the plate 3 a and is supplied to the sliding portion between the thrust surface 3 f of the orbiting scroll 3 and the thrust plate 15. In addition, oil is supplied to the sliding portion when oil adheres to the protruding surface of the thrust surface 3 f of the orbiting scroll 3. This operation is repeated for each rotation.

  In the present embodiment, the thrust plate 15 is made of a hard steel plate having a surface roughness of 0.5Z or less, and the surface roughness of the thrust surface 3f of the orbiting scroll 3 is 3.5Z or less. The smaller the surface roughness of the shaft and the bearing, the more easily an oil film is generated on the contact surface, and the slidability is improved. Since the thrust plate 15 can be barreled or polished, it can be 1.0Z or less.

  Thrust receivers (slide bearings) made of conventional bronze metal are difficult to cut due to the nature of the material, and the surface roughness of about 3.5Z is the limit. This increases the cost. On the other hand, the thrust surface when the orbiting scroll 3 is made of cast iron (FCD450) can be cut due to the properties of the material, but the surface roughness of 3.5Z is the limit from the tool life. Therefore, the surface roughness of the thrust surface is equivalent to that of a bronze metal thrust bearing (slide bearing), and sufficient slidability can be obtained.

  With the above configuration, a compressor using a conventionally used R410A refrigerant, an R32 refrigerant equivalent to the R410A refrigerant, a mixed refrigerant of R32, or a CO2 refrigerant having a large operating pressure, is used for a thrust bearing part. Without treatment, the thrust bearing portion can be sufficiently lubricated by using ester (POE), ether (PVE), or polyalkylene glycol (PAG) oil as the refrigerating machine oil.

  In this embodiment, the fixed scroll 2 is made of cast iron such as FCD450, the orbiting scroll 3 is made of cast iron of the same material as the fixed scroll, and the thrust plate 15 is made of hard steel plate such as valve steel. Yes. Since the fixed scroll 2 and the orbiting scroll 3 are made of cast iron of the same material, even if the temperature of the compression portion rises and the thermal expansion occurs during the operation of the compressor 1, the fixed scroll 2 and the orbiting scroll 3 There is no leakage gap between the two.

  As described above, the thrust bearing portion of the present embodiment uses the thrust plate 15 that is a member for adjusting the tip clearance as a member of the thrust bearing, and the thrust surface 3f of the orbiting scroll 3 is the thrust plate. 15 and a simple structure that slides directly on the lower surface of the thrust plate 15 and the bottom surface of the base plate 3a of the orbiting scroll 3 as in the conventional thrust receiver. A costly thrust bearing can be realized.

Embodiment 2. FIG.
In FIG. 7, the principal part cross section of the thrust bearing part in this Embodiment 2 is shown. The thrust surface 3f of the orbiting scroll 3 described in the first embodiment is a flat surface. On the other hand, in the present embodiment, an angle 3h between the thrust surface 3f and the outer peripheral surface 3g is formed by a curved surface (for example, an arc), and the curved surface is in contact with the thrust surface 3f, whereby the plane of the thrust surface 3f is obtained. And the joint of the curved surface of the corner 3h on the outer peripheral side is made smooth. As a processing method, for example, there is a method of processing the thrust surface 3f and the outer peripheral surface 3h at once with a lathe.

  With the above-described configuration, compared to the case where the corner 3h between the thrust surface 3f and the outer peripheral surface 3g of the orbiting scroll 3 is formed by chamfering, the edge does not stand even when the orbiting scroll 3 is tilted, and the orbiting scroll. An oil film is formed on the contact surface between the thrust surface 3f and the thrust plate 15.

  When the corner 3h between the thrust surface 3f and the outer peripheral surface 3g is chamfered, when the orbiting scroll 3 is tilted, the edge of the joint between the thrust surface 3f and the chamfer is brought into contact with the thrust plate 15, and the metal between which the oil film is not generated Since the contact occurs, the function of the thrust bearing portion is lowered, and the life of the thrust plate 15 is shortened.

  Therefore, by forming the corner 3h between the thrust surface 3f and the outer peripheral surface 3g of the orbiting scroll 3 with a curved surface (for example, an arc), a thrust bearing portion having a good slidability can be obtained while having a small number of components. Can do.

DESCRIPTION OF SYMBOLS 1 Scroll compressor 2 Fixed scroll 2a, 3a Base plate 2b, 3b Spiral tooth 2c, 3e Groove 3 Oscillating scroll 3c Boss part 3d Oscillating bearing 3f Thrust surface 3g Outer peripheral surface 3h Square 4 Stator 5 Rotor 6 Main shaft 7 Slider DESCRIPTION OF SYMBOLS 8 Eccentric shaft part 9 Shell 10 Intake pipe 11 Discharge pipe 12 Frame 12a Bottom part 12b Main bearing 12c Inlet 13 Positive displacement oil pump 14 Oldham ring 15 Thrust plate 16 Collar part 17 Compression chamber 18, 19 Seal 20 Discharge port 21 Subframe 22 Oil drain hole 23 Lower space in the frame 24 Discharge space

Claims (1)

A fixed scroll provided in the upper part of the hermetic shell and having spiral teeth formed on the base plate;
A rocking scroll comprising a compression portion together with the fixed scroll, a spiral tooth formed on the base plate, and a boss portion having a rocking bearing at the center of the bottom surface;
An eccentric shaft portion that is rotatably engaged with the rocking bearing via a slider is formed at the upper end, and a main shaft that is rotationally driven by an electric motor;
It has a bottomed cylindrical shape, the outer periphery is fixed to the inner peripheral surface of the shell, the base plate of the fixed scroll is abutted and fixed to the upper end surface of the open side across the swing scroll, and the main shaft is rotated at the bottom In a scroll compressor comprising a frame formed with a main bearing that is freely supported,
A ring-shaped thrust plate is disposed between the rocking scroll and the bottom of the frame, and a ring-shaped thrust surface protruding downward is formed on the outer peripheral side of the bottom surface of the base plate of the rocking scroll. A thrust bearing portion is constituted by the thrust plate and the thrust surface;
A scroll compressor, wherein a flange portion is formed on a part of an outer periphery of the ring-shaped thrust plate, and the flange portion is accommodated in an intake port formed in the frame.

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