JP5433603B2 - Scroll compressor - Google Patents

Description

  The present invention relates to a scroll compressor, and more particularly to a structure of a turning scroll.

  The scroll compressor revolves at a constant eccentric distance from the center of the crankshaft without the orbiting scroll rotating. Therefore, a centrifugal force corresponding to the mass of the orbiting scroll, the position of the center of gravity, the eccentric distance, and the rotational speed is generated in the orbiting portion of the crankshaft, and this centrifugal force deflects the upper part of the crankshaft in the direction of the centrifugal force (perpendicular to the axis). I will. The deflection of the crankshaft causes the orbiting scroll to oscillate and the contact between the orbiting scroll and the fixed scroll lap side surface becomes larger than necessary, and the contact pressure between the crankshaft and the bearing is biased. This will adversely affect the performance of the compressor, such as reduced efficiency, noise, and reduced life reliability due to increased wear.

  Thus, as one means for reducing the centrifugal force, it has been conventionally performed to make the center of gravity of the orbiting scroll coincide with the center of the orbiting end plate. For example, in a spiral wrap shape constituted by an involute curve or the like, the center of gravity usually does not coincide with the center of the end plate.

  As a method of bringing the position of the center of gravity closer to the end plate center, for example, as in Patent Document 1, there is a method of translating the spiral center of the wrap in the direction opposite to the center of gravity direction viewed from the end plate center. On the other hand, as a method of adjusting the center of gravity to the center of the end plate without changing the wrap itself, there is a method of balancing by turning the side opposite to the center of gravity of the orbiting scroll end plate. However, the latter method has a problem that the strength is reduced by cutting the end plate.

  During operation of the compressor, a load corresponding to the refrigerant pressure is applied to the orbiting scroll from each of the compression chambers, the back pressure chamber, and the like, so that deformation corresponding to the pressure occurs. The deformation of the orbiting scroll affects the shape of the gap between the wrap tooth tip and the side surface, and due to the non-uniformity of the gap, refrigerant leakage from the gap increases to reduce the volume efficiency of the compressor. Therefore, the reduction in the amount of deformation of the orbiting scroll leads to improvement in the efficiency of the compressor due to the improvement in volumetric efficiency.

  In order to improve the above problems, it is necessary to reduce the cutting amount of the end plate. Since the cutting amount is smaller as the cutting part is located on the outer peripheral side of the end plate, a structure that cuts the outer side further than the outermost outer periphery of the lap is desirable. An example of a structure close to that is Patent Document 2.

JP 2008-133806 A Japanese Patent Application Laid-Open No. 08-028460

  As a method of making the center of gravity of the orbiting scroll coincide with the center of the end plate, there are a method of translating the position of the wrap and a method of balancing by cutting the end plate.

  However, the former method may not be possible with conventional orbiting scroll processing equipment, which requires the introduction of a new large-scale equipment, which is not always easy to implement. . Therefore, on the premise of the latter method of processing the end plate, the method will be described below.

  In the conventional orbiting scroll, the balance plate as shown in FIG. However, in such a structure in which the bottom area of the hole is large and the end plate is so large that it extends to the back of the compression chamber, not only does the strength decrease in the balance hole portion and the deformation amount increases, but also depending on the crank angle. As the deformation amount itself fluctuates, there is a problem that the refrigerant leaks from the compression chamber and acts in the direction of increasing the deformation, resulting in a large deformation.

  Also, in the sense of center of gravity alignment, it is conceivable to cut a balance hole on the side of the lap of the end plate, but the end surface of the lap side plate plays the role of sealing the refrigerant leakage between the compression chamber, the back pressure chamber and the suction chamber. In addition, the cutting of the lapping-side panel surface may reduce the contact area between the orbiting scroll and the fixed scroll, which are the sealing surfaces of the refrigerant, and may increase refrigerant leakage in the compression chamber. For example, Patent Document 2 does not mention that, but in fact, the size of the end plate is designed to be a minimum size that can ensure sufficient sealing performance for the purpose of reducing the weight and reducing the cost. The structure of cutting the end plate wrap side is difficult to adopt in practice in the sense that the secured sealing performance is lowered. If these points can be improved, the efficiency can be improved.

  An object of the present invention is to provide a highly efficient scroll compressor.

The purpose of the present invention is to
An orbiting scroll having a spiral wrap standing on the base plate;
In a scroll compressor having a fixed scroll that forms a compression chamber and a suction chamber inside and outside the lap of the orbiting scroll and meshing with each other,
In the direction of the center of gravity of the wrap of the orbiting scroll from the center of gravity of the base plate, an arc-shaped groove is provided on the side opposite to the base plate ,
This is achieved by forming the groove outside the wrap of the orbiting scroll .

  According to the present invention, a highly efficient scroll compressor can be provided.

The structure of the scroll compressor. The rear view of the conventional turning scroll. The turning scroll structure of 1st Embodiment in this invention. The turning scroll structure (perspective view) of 1st Embodiment in this invention. The center of gravity trajectory of the orbiting scroll. Influence on the centrifugal force due to the deviation of the center of gravity. An example of cutting between the strings and the outer periphery of the orbiting scroll end plate wrap side. An arc-shaped cutting example on the orbiting scroll end plate wrap side. Fixed scroll orbiting scroll end plate contact surface. The vertical sectional view of a fixed scroll and a turning scroll. Dependence of the tip efficiency on the compressor efficiency. Stress distribution on the back side of the orbiting scroll. Comparison of deformation amount of orbiting scroll by balance hole shape. Orbiting scroll sandwich structure. 2nd Embodiment (turning scroll) in this invention. 3rd Embodiment (turning scroll) in this invention. 4th Embodiment in this invention (turning scroll). Conventional frame structure. 5th Embodiment (frame) in this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  A first embodiment of the present invention will be described below in detail with reference to FIGS.

  A basic configuration of the scroll compressor of the present invention will be described with reference to FIG. The scroll compressor 1 includes a compression mechanism unit 3 composed of an orbiting scroll 6 and a fixed scroll 5 provided with spiral wraps 6a and 5c, an electric motor 4 for driving the compression mechanism unit 3, and the compression mechanism unit 3 An airtight container 2 for storing the electric motor 4 is provided. A compression mechanism unit 3 is disposed in the upper part of the sealed container 2, and an electric motor 4 is disposed in the lower part. A lubricating oil 13 is stored at the bottom of the sealed container 2.

  The sealed container 2 is configured by welding a lid chamber 2b and a bottom chamber 2c up and down to a cylindrical case 2a. The lid chamber 2b is provided with a suction pipe 2d, and a discharge pipe 2e is provided on the side surface of the case 2a. The inside of the sealed container 2 is a discharge pressure chamber 2f.

  The compression mechanism unit 3 is integrated with the fixed scroll 5 having the spiral wrap 5c on the end plate 5d, the orbiting scroll 6 having the spiral wrap 6a on the end plate 6b, and the fixed scroll 5 with a bolt 8. And a frame 9 that supports the orbiting scroll 6.

  The frame 9 includes a main bearing 9a that rotatably supports the crankshaft 7. An eccentric portion 7 b of the crankshaft 7 is connected to the lower surface side of the orbiting scroll 6.

  An Oldham ring 12 is disposed between the lower surface side of the orbiting scroll 6 and the frame 9. The Oldham ring 12 is mounted in a groove formed on the lower surface side of the orbiting scroll 6 and a groove formed on the frame 9. Yes. The Oldham ring 12 functions to revolve by receiving the eccentric rotation of the eccentric portion 7 b of the crankshaft 7 without rotating the orbiting scroll 6.

  The electric motor 4 includes a stator 4a and a rotor 4b. The stator 4a is fastened to the sealed container 2 by press-fitting or welding. The rotor 4b is rotatably arranged in the stator 4a. A crankshaft 7 is fixed to the rotor 4b.

  The crankshaft 7 includes a main shaft 7 a and an eccentric portion 7 b and is supported by a main bearing 9 a and a lower bearing 17 provided on the frame 9. The eccentric portion 7 b is formed integrally with the main shaft 7 a of the crankshaft 7, and is fitted to a orbiting bearing 6 c provided on the back surface of the orbiting scroll 6. The crankshaft 7 is driven by the electric motor 4, and the eccentric portion 7b is eccentrically rotated with respect to the main shaft 7a, thereby causing the orbiting scroll 6 to orbit. Further, the crankshaft 7 is provided with an oil supply passage 7c that guides the lubricating oil 13 to the main bearing 9a, the lower bearing 17 and the slewing bearing 6c.

  When the orbiting scroll 6 orbits through the crankshaft 7 driven by the electric motor 4, the refrigerant gas is guided from the suction pipe 2 d to the compression chamber 11 formed by the orbiting scroll 6 and the fixed scroll 5. The volume is reduced and compressed as it moves in the center of the scroll. The compressed refrigerant gas is discharged to the discharge pressure chamber 2f in the sealed container 2 from the discharge port 5e provided at the substantially center of the end plate 5d of the fixed scroll 5, and flows out from the discharge pipe 2e to the outside.

  FIG. 2 shows a view of a conventional orbiting scroll viewed from the back side (anti-lap side). The wrap 6a is configured based on an involute curve, and the position of the center of gravity of only the wrap is positioned on the winding end side outside the spiral from the end plate center. Therefore, when there is no balance hole, the center of gravity of the entire orbiting scroll is also located in the direction of the end of the wrap winding.

  3 and 4 show the shape of the orbiting scroll 6 in this embodiment, compared to the conventional example. In this shape, the two circular balance holes on the back surface of the end plate shown in FIG. 2 are eliminated, and instead, the balance hole 6d is formed by cutting the outermost peripheral portion of the back surface into an arc shape along the outer periphery. Cutting is performed from the back side without penetrating the end plate surface, and the depth is set to the bottom surface position of the groove on the side surface of the end plate. Further, as a feature, the inner side of the lap formed on the side opposite to the end plate is not cut, and the part from the outer side to the outermost circumference is cut. The details of the length and position of the arc to be cut are determined by the center of gravity balance of the orbiting scroll. Below, the effect when using the structure of a present Example and its reason are demonstrated.

  First, the influence on the compressor when the center of gravity deviates from the center of the end plate will be described. FIG. 5 shows the rotational movement of the center of gravity of the orbiting scroll relative to the center of the crankshaft 7 when viewed from the tooth tip direction of the orbiting scroll 6, and the lower figure is seen in the vertical section of the orbiting scroll. The rotation axis of the center of gravity is shown. The broken and solid circles correspond to the case where the center of gravity is shifted from the center of the end plate and the case where it is not.

  As an example of a value close to the actual structure, the center-of-gravity shift distance is 1/3 of the eccentric amount from the center of the crankshaft of the orbiting scroll. While the center of the orbiting scroll rotates on the circular orbit indicated by the solid line, the orbiting scroll itself does not rotate, so the center of gravity deviation from the solid line circle is always the same direction and the same distance, and the misaligned center of gravity is the broken circle Move on a circular orbit like this.

  Considering the motion of the orbiting scroll as a mass point located at the center of gravity, the centrifugal force acting on the orbiting scroll is proportional to the distance from the center of the crankshaft, so the dependence of the centrifugal force on the crankshaft rotation angle is as shown in FIG. It becomes a graph. Here, the ratio of the centrifugal force when the centrifugal force without deviation of the center of gravity is set to 1 is the vertical axis. When there is no center-of-gravity shift, the centrifugal force is constant, but when there is a center-of-gravity shift, the centrifugal force fluctuates periodically as shown by the broken line.

  Whether the centrifugal force is constant or not is essentially different in the following meaning. If the centrifugal force is constant, the overall centrifugal force can be canceled by providing the balance weight 23 of FIG. However, if the centrifugal force fluctuates due to the deviation of the center of gravity as indicated by the broken line in FIG. 6, the balance weight 23 cannot cancel the centrifugal force. Therefore, the load on the crankshaft is also periodically fluctuated, and the orbiting scroll is swung during rotation to generate vibration and noise, and the volume efficiency is reduced due to the increase between the lap gaps of the fixed scroll 5 and the orbiting scroll 6. Adversely affects. Therefore, correcting the center of gravity to the center is important for improving the quality of the compressor and reducing noise. Conventionally, a circular balance hole 6d as shown in FIG. Had gone.

  In addition to the balance hole 6d shown in FIG. 2, for example, a method of adjusting the center of gravity by scraping the lap side of the end plate 6b can be considered. FIG. 7 and FIG. 8 show the cutting shapes necessary for center-of-gravity alignment when the portion surrounded by the chord and the outer periphery on the orbiting scroll end plate wrap side is cut and when it is cut into an arc shape. Here, the spiral one-dot chain line in the figure shows a part of the envelope formed by the fixed scroll extension, and the compression chamber is formed inside the outermost periphery of this chain line. Therefore, it cannot cut into this dashed-dotted line, and cannot take a shape like FIG. 7, FIG. In particular, as shown in this embodiment, in the asymmetric wrap in which the wrap winding end positions of the fixed scroll and the orbiting scroll are the same, the compression chamber forming region extends outward at the suction portion at the end of winding, and the center of gravity is also wound. Since it is located on the end side, it is more difficult to secure a sufficient cutting allowance.

  FIG. 9 shows the fixed scroll 5, and the hatched portion indicates the contact surface with the orbiting scroll 6. The end plate 6b outside the outermost one-dot chain line outer periphery of the orbiting scroll 6 in FIGS. 7 and 8 serves to seal the compression chamber and the back pressure chamber (suction chamber) by contacting the hatched portion of the fixed scroll. Even outside the alternate long and short dash line, leakage of the refrigerant increases by scraping the end plate. On the other hand, it is desirable that the end plate of the orbiting scroll should be made smaller as long as the sealing performance can be secured from the viewpoints of weight reduction, cost reduction, friction reduction, etc. Can be said to have various difficulties. From the above, the structure is such that the back side of the orbiting scroll end plate 6b is cut.

  Next, the deformation of the orbiting scroll 6 and the influence on the lap gap, and the influence of refrigerant leakage from the gap on the compressor efficiency will be described. FIG. 10 is a view showing the meshing of the wrap between the fixed scroll 5 and the orbiting scroll 6 by a vertical section. The refrigerant is compressed in a compression chamber formed by meshing two scroll wraps. At that time, gaps in the order of microns covered with an oil film are formed between the bottoms and side surfaces of the wrap tooth tips, and the refrigerant is enclosed. Here, if the orbiting scroll end plate is deformed, the tooth tip gap is narrowed and widened. There is an appropriate value for the distance between the tooth gaps. If the distance is too large, the refrigerant leakage increases and the volumetric efficiency decreases. If the distance is too small, the frictional force increases and the energy loss increases. Furthermore, when the deformation varies depending on the rotation angle, the gap width also varies, and on average the refrigerant leakage increases, leading to a decrease in volumetric efficiency.

  FIG. 11 shows a simulation of the efficiency of the compressor when the tooth tip gap is changed. In the case 2, the tooth tip gap is uniformly narrowed in the case 2. From this result, it can be said that the reduction of the gap improves the volumetric efficiency and the efficiency of the compressor.

  Next, a structure for reducing the deformation amount while matching the center of gravity of the orbiting scroll with the center will be described. The reason why the orbiting scroll provided with the balance hole 6d is likely to be deformed as shown in FIG. 2 is that the thickness of the end plate 6b is reduced in the balance hole 6d and greatly deformed there. Therefore, in order to reduce the deformation amount, it is desirable that the cutting amount is small. Since the purpose of cutting is to balance the center of gravity, the center of gravity can be centered with a smaller amount of cutting by cutting away from the center. In fact, when the cutting amount is compared between the above-described conventional example and the shape of the present embodiment described below, the volume ratio in the present embodiment is reduced to about 66%.

  On the other hand, FIG. 12 shows the calculation result of the stress distribution on the line along the back side surface of the orbiting scroll 6 indicated by the broken line A in FIG. 12 when the orbiting scroll without the balance hole 6d is deformed. Yes. The stress decreases as it goes from the center side of the end plate 6b toward the outer peripheral side, and the stress is weakened toward the outside. In this case, the stress at the outer peripheral portion is less than half of the center side, and even if it is considered that cutting is performed with the same shape, it can be said that the amount of deformation can be suppressed when the cutting position is on the outer peripheral side. Furthermore, as described above, the lap side end plate surface of the orbiting scroll plays a role of sealing the refrigerant in the compression chamber, so that it is desirable to perform the cutting on the back side of the end plate.

  If the above is arranged, it can be said that the structure in which the cutting area is on the back side of the end plate and the portion near the outer peripheral side is not penetrated is more suitable as a structure for improving the center of gravity, deformation, and refrigerant sealability. The structure is shown in FIGS. 3 and 4 as this embodiment.

  FIG. 13 shows a comparison graph of the amount of deformation in the tooth tip direction of the orbiting scroll 6 depending on the presence / absence of the balance hole 6d and the shape difference using numerical deformation analysis. Here, the conventional structure having two circular balance holes shown in FIG. 2 is taken as a conventional example, the deformation amount is set to 100%, and the deformation amount in the structure in which the center of gravity is not adjusted without the balance hole is set to 0. %, The increase in deformation due to cutting for center of gravity alignment was evaluated. According to the evaluation method, in the structure of the present embodiment shown in FIGS. 3 and 4, the deformation amount is reduced by about 80% compared to the conventional case, and the deformation is reduced to 23% compared with the conventional case. It was. As a result of reducing the deformation amount in the cutting part for center of gravity alignment, not only the deformation amount at one rotation angle is reduced, but also the variation of the deformation amount when the rotation angle changes is suppressed, and the center of gravity is suppressed. Along with the uniformizing of the centrifugal force during rotation by the combination, it is also uniformed in the deformation of the turning scroll during rotation, and a turning scroll with a better balance of the center of gravity is realized. As a result, the refrigerant sealability between the compression chamber, the back pressure chamber, and the suction chamber is improved, the volume efficiency is improved, and a highly efficient scroll compressor can be realized.

  A second embodiment of the present invention will be described with reference to FIGS.

  Before the scroll compressor 1 is started, the orbiting scroll 6 is slightly separated from the fixed scroll 5, and the end plate 6 b is on the frame 9. When the compressor is activated and the pressure in the back pressure chamber increases, the orbiting scroll 6 rises due to the back pressure and comes into contact with the fixed scroll 5. The figure shows a partial cross-sectional view of the compression mechanism section 3. As shown by B in FIG. 14, the vertical movement of the orbiting scroll 6 is suppressed by being sandwiched between the fixed scroll 5 and the frame 9.

  In Embodiment 1, the shape which cuts the outer peripheral part by the side of a turning mirror board back in circular arc shape was shown for the purpose of deformation amount reduction. Since the turning end plate cannot be sandwiched in the cutting portion, the orbiting scroll 6 is sandwiched between the remaining outer peripheral portions. As shown in FIG. 14B, since the gap between the fixed scroll 5 and the frame 9 is very small, for example, the orbiting scroll 6 does not completely disengage from the fixed scroll 5 and does not tilt significantly. However, if the portion that sandwiches the orbiting scroll 6 is biased, there is a possibility that minute backlash or the like may occur. The second embodiment has a shape for improving the point.

  FIG. 15 shows the shape of the back side of the orbiting scroll in this embodiment. Here, the arcuate groove 6d provided in the first embodiment is divided into two parts. Thereby, the length of one arc of a cutting part becomes short, a turning mirror board is inserted | pinched in the intermediate non-cutting part, and the vertical movement in the cutting part of a turning mirror board can be suppressed more. Similarly, a structure of three or more divisions can be considered.

  As described above, the tilt of the orbiting scroll during operation can be further reduced, the volume efficiency is improved, and a more efficient scroll compressor can be realized.

  Hereinafter, a third embodiment will be described with reference to FIG.

  As shown in FIG. 2, conventionally, a structure in which the balance hole 6d is formed in a circular shape has been used. Its size was a shallow and wide structure that extended inward from the outermost circumference of the lap. However, considering the small deformation of the orbiting scroll 6, a structure in which a cutting amount can be reduced and a balance hole is provided on the outer peripheral side (FIG. 10) of the end plate with less stress is more desirable. On the other hand, making the balance hole circular does not require a large-scale change in the conventional processing equipment for the balance hole, and can be manufactured more easily than making the shape other than circular.

  From the above two points, the structure of the orbiting scroll in the third embodiment is shown in FIG. The balance hole is circular, the diameter is reduced and the number is increased to five here so as to be located outside the outermost periphery of the lap and as far as possible. As a result, the amount of cutting for correcting the balance of the center of gravity is reduced while taking the conventional method of a circular balance hole, and the amount of deformation of the orbiting scroll is reduced because the cutting is performed at a position with less stress. By improving efficiency, a more efficient scroll compressor can be realized.

  Hereinafter, a fourth embodiment will be described with reference to FIGS.

  As described above, in order to reduce the deformation of the orbiting scroll 6, it is important to reduce the cutting amount of the orbiting scroll. On the other hand, the orbiting scroll is provided with radial grooves 6e on the outer peripheral portion on the back side and grooves on the side surface of the end plate in order to prevent oil from being compressed during rotation. Since these are provided for the purpose of creating an escape path so that the oil is not compressed, there is no necessity to provide a groove in the orbiting scroll if a similar path can be formed. Therefore, instead of eliminating these grooves, a structure in which similar grooves are provided on the frame side can be considered. This is a fourth embodiment, FIG. 17 shows the orbiting scroll 6, and FIGS. 18 and 19 show the conventional example and the frame 9 in this embodiment, respectively. Compared to the conventional structure shown in FIG. 18, a radiation groove 9 b and a circumferential groove 9 c are added to the frame in this embodiment shown in FIG. 19. Since these grooves are provided on the point object with respect to the center of the end plate, a change in the center of gravity balance due to the abolishment of these grooves does not occur. Therefore, if the same groove is provided on the frame side in the vicinity of the grooves instead of eliminating the above-described grooves 6e and 6f, the cutting amount of the orbiting scroll 6 can be reduced. Thus, the deformation can be further reduced, and the volumetric efficiency can be improved by shortening the gap between the orbiting scroll 6 and the fixed scroll 5. Therefore, a more efficient scroll compressor can be realized.

  As in each of the embodiments described above, by providing a cutting portion having a shape that is smallly deformed while being centered on the center of gravity with respect to the orbiting scroll, the sealing performance of refrigerant leakage in the compression chamber is provided on the outer periphery of the end plate and the side opposite to the wrap. The volume efficiency can be improved by the improvement. Therefore, a highly efficient scroll compressor can be realized.

DESCRIPTION OF SYMBOLS 1 Scroll compressor 2 Sealed container 2a Case 2b Cover chamber 2c Bottom chamber 2d Suction pipe 2e Discharge pipe 2f Discharge pressure chamber 2g End surface 3 Compression mechanism part 4 Electric motor 4a Stator 4b Rotor 5 Fixed scroll 5c, 6a Wrap 5d, 6b 5e Discharge port 6 Orbiting scroll 6c Orbiting bearing 6d Balance hole 6e, 9b Radiation groove 6f Outer peripheral groove 7 Crankshaft 7a Main shaft 7b Eccentric part 7c Oil supply passage 8 Bolt 9 Frame 9a Main bearing 9c Circumferential groove 11 Compression chamber 12 Oldham ring 13 Lubrication Oil 17 Lower bearing 19 Spring 22 Valve body 23 Balance weight

Claims (6)

An orbiting scroll having a spiral wrap standing on the base plate;
In a scroll compressor having a fixed scroll that forms a compression chamber and a suction chamber inside and outside the lap of the orbiting scroll and meshing with each other,
In the direction of the center of gravity of the wrap of the orbiting scroll from the center of gravity of the base plate, an arc-shaped groove is provided on the side opposite to the base plate ,
A scroll compressor characterized in that the groove is formed outside the wrap of the orbiting scroll .   In claim 1,
  The orbiting scroll is sandwiched between the frame fixed to the fixed scroll, the step provided in the frame, the step and the fixed scroll,
  A scroll compressor characterized in that a flat portion facing the step portion is provided in the groove. The scroll compressor according to claim 2, wherein a plurality of the flat portions are provided.   In claim 1,
  The orbiting scroll is sandwiched between the frame fixed to the fixed scroll, the step provided in the frame, the step and the fixed scroll,
  A scroll compressor characterized in that an oil discharge passage is provided in the stepped portion.   The scroll compressor according to claim 4, wherein a plurality of the oil discharge passages are provided.   6. The scroll compressor according to claim 1, wherein the wrapping angle of the orbiting scroll and the fixed scroll is an asymmetric wrap in which the winding angles are shifted from each other by about 180 degrees.