JP5581440B2 - Scroll compressor - Google Patents

Description

  The present invention relates to a scroll compressor used in a refrigerating and air-conditioning apparatus, and more particularly to a scroll compressor provided with an orbiting slide bearing that engages and slides with an eccentric portion of a crankshaft.

  The scroll compressor is a compressor that compresses a gas such as a refrigerant by relatively rotating two scroll members having a spiral tooth shape. Generally, the other movable orbiting scroll is configured to orbit with respect to a fixed scroll that is constrained by screws or welding. The orbiting scroll is provided with an orbiting sliding bearing that engages and slides with the eccentric portion of the crankshaft, while the eccentric portion of the crankshaft and the orbiting sliding bearing slide through the lubricating oil, Many mechanisms have been adopted in which the rotational movement of the crankshaft is transmitted to the orbiting scroll for the orbiting movement.

In recent years, in order to reduce the energy consumption of the scroll compressor and reduce the load on the electric motor, reduction of bearing loss caused by sliding between the shaft and the bearing has been an issue.
As a conventional technique for reducing the bearing loss, there is a technique described in Japanese Patent Laid-Open No. 2003-239876 (Patent Document 1). This document states that “a floating ring member is rotatably and idly held in a hub insertion groove formed in a lower part of the orbiting scroll, and a sliding bush fixed to an eccentric portion of a rotating shaft at the center of the floating ring member. Is inserted to constitute a friction loss reducing device for a scroll compressor. "

  In general, it is known that in a sliding portion such as a bearing in which two surfaces slide and slide via lubricating oil, friction loss increases as the sliding speed increases. In the thing of the said patent document 1, it is set as the structure which inserted the slide bush which can rotate in the space between the eccentric part of the rotating shaft filled with lubricating oil, and a hub (rotating boss | hub part). As a result, the sliding that occurs between the rotating shaft and the hub is distributed to the sliding between the outer periphery of the rotating shaft and the inner periphery of the slide bush and the sliding between the outer periphery of the slide bush and the inner periphery of the hub. The relative sliding speed at each sliding part is reduced, and the friction loss of the bearing during high speed operation is reduced.

  As another prior art, there is one described in JP-A-11-159484 (Patent Document 2). This patent document 2 states that “a D-cut is formed on the outer peripheral surface of the eccentric pin portion within the range of 30 ° or more and 120 ° or less from the eccentric direction of the eccentric pin portion to the crankshaft in the counter-rotating direction with respect to the crankshaft. It is described. In addition, the D cut is described as “a lubrication notch is provided in a relatively large area between the eccentric shaft portion and the bearing portion”.

  By providing the oil supply notch (D cut) in a relatively large area between the eccentric shaft part and the bearing part, stable oil supply is promoted during start-up, low-speed operation and transient operation. Prevention and ensuring fluid lubrication. As a result, direct contact between the outer periphery of the crankshaft and the inner periphery of the bearing is prevented, and an increase in friction loss can be prevented.

JP 2003-239876 A JP-A-11-159484

  However, in the above-mentioned Patent Document 1, since the number of parts increases, the structure becomes complicated, and the number of sliding parts also increases. Therefore, new problems arise, such as high management accuracy required for the bearing gap dimension. Further, during low speed operation, there is a problem that an oil film is difficult to be formed due to a decrease in the sliding speed, and direct contact with the slide bush is likely to occur.

  Further, in the above-mentioned Patent Document 2, it is effective in that the lubricating oil flows from the outside into the bearing gap to prevent the oil film from being cut and the direct contact between the shaft and the bearing is prevented. Since a notch is provided at a large gap with the part, reduction of the shear resistance of the fluid lubricating oil film cannot be expected or the reduction effect is small. Therefore, once the fluid lubricating oil film is formed and the state without the direct contact portion is formed, the loss is not further reduced or is limited.

  An object of the present invention is to reduce bearing loss during fluid lubrication by reducing the shear resistance of an oil film caused by lubricating oil existing between the outer peripheral surface of the eccentric portion of the crankshaft and the inner peripheral surface of the orbiting slide bearing. It is to reduce.

  In order to achieve the above object, the present invention provides a fixed scroll, a turning scroll meshing with the fixed scroll, a crankshaft having an eccentric portion at the end for turning the turning scroll, and a shaft inside the crankshaft. An oil supply hole penetrating in the direction and having an opening at an end surface of the eccentric portion, a orbiting sliding bearing provided in the orbiting scroll and slidably engaged with the eccentric portion of the crankshaft, and the eccentric portion of the crankshaft An oil supply passage provided on the outer periphery of the eccentric portion so as to communicate the upper end side and the lower end side of the eccentric portion, and lubrication between the eccentric portion and the orbiting slide bearing is performed by the lubricating oil supplied from the oil supply hole. In the scroll compressor configured to perform the axial loss reduction groove provided separately from the oil supply passage on the outer periphery of the eccentric portion of the crankshaft, and the eccentricity in the loss reduction groove Characterized in that it comprises a sealing portion provided at least one end face side and the proximal side of the.

  According to the present invention, the shear resistance of the oil film due to the lubricating oil existing between the outer peripheral surface of the eccentric part of the crankshaft and the inner peripheral surface of the orbiting sliding bearing can be reduced, and the bearing loss during fluid lubrication is reduced. There is an effect that can be done.

It is a longitudinal cross-sectional view which shows Example 1 of the scroll compressor of this invention. FIG. 2 is an enlarged perspective view near an eccentric portion shown in FIG. 1. It is an expanded sectional view of the eccentric part vicinity shown in FIG. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is CC sectional drawing of FIG. It is a figure explaining the shaft rotation direction in the BB cross section of FIG. 3, an angular position, and a bearing load direction. FIG. 4 is a diagram for explaining a start position of a loss reduction groove in the present invention, where (a) is a diagram for explaining the relationship between the start position of the loss reduction groove and relative bearing loss, and (b) is a relative view of the start position of the loss reduction groove. It is a diagram explaining the relationship with the minimum oil film thickness. It is a diagram explaining the relationship between the depth of the loss reduction groove | channel and relative bearing loss in this invention. It is a diagram explaining the relationship between the circumferential direction angular width of the loss reduction groove | channel in this invention, and a relative bearing loss. It is a diagram explaining the relationship between the rotational speed of the axis | shaft in this invention, and a relative bearing loss. It is an expansion perspective view of the eccentric part vicinity which shows the other example of the loss reduction groove | channel provided in the outer periphery of a crankshaft. It is an expansion perspective view of the eccentric part vicinity which shows the other example of the loss reduction groove | channel provided in the outer periphery of a crankshaft. It is an expansion perspective view of the eccentric part vicinity which shows the other example of the loss reduction groove | channel provided in the outer periphery of a crankshaft.

  Hereinafter, specific examples of the scroll compressor of the present invention will be described with reference to the drawings. In each figure, the part which attached | subjected the same code | symbol has shown the part which is the same or it corresponds.

FIG. 1 is a longitudinal sectional view showing Embodiment 1 of the scroll compressor of the present invention.
A scroll compressor 1 shown in FIG. 1 is a hermetic scroll compressor used for an air conditioner such as an air conditioner or a refrigeration air conditioner such as a refrigeration apparatus. A fixed scroll 112 and an orbiting scroll 109 that engages with the fixed scroll 112 and performs an orbiting motion are provided at the upper part in the sealed container 2. An electric motor 102 is provided in the sealed container 2, and a crankshaft 103 is connected to the electric motor 102, and the crankshaft 103 is a main bearing provided on a frame 104 fixed in the sealed container 2. 105 and a sub-bearing 107 provided on the lower frame 106 are rotatably supported.

  An eccentric part 108 is provided at the upper part of the crankshaft 103, and the eccentric part 108 engages and slides with the orbiting sliding bearing 110 provided on the lower surface of the end plate of the orbiting scroll 109. The whirling rotational motion (eccentric motion) is transmitted to the orbiting scroll 109. The orbiting scroll 109 is controlled to rotate by the Oldham ring 111 and revolves with respect to the fixed scroll 112. Thereby, the low-pressure refrigerant gas is sucked from the suction port 113 and compressed, and then discharged to the outside through the discharge port 114.

  The crankshaft 103 is provided with an oil supply hole 115 penetrating from the lower end thereof to the end surface (upper end surface) side of the eccentric portion 108, and the lubricating oil 3 stored in the lower part of the sealed container receives the pressure difference. Or by a pump separately attached to the lower end portion of the crankshaft so as to be pushed up through the oil supply hole 115 and supplied to a sliding portion such as each bearing portion (main bearing 105, sub-bearing 107, slewing sliding bearing 110). It is configured. In the present embodiment, the inside of the sealed container 2 has a discharge pressure, and the intermediate chamber (back pressure chamber) 119 on the back of the end plate of the orbiting scroll 109 has an intermediate pressure between the discharge pressure and the suction pressure. . For this reason, the lubricating oil stored in the lower part of the sealed container is supplied to the bearings and the like through the oil supply holes 115 due to a pressure difference between the discharge pressure and the intermediate pressure.

  FIG. 2 is an enlarged perspective view near the eccentric portion 108 shown in FIG. The oil supply hole 115 is opened at the upper end surface of the eccentric portion 108. The eccentric portion 108 is provided with an axial oil supply passage 116 so as to communicate from the upper end (end surface) 108a side to the lower end (base end) 108b side. In addition to the oil supply passage 116, a loss reduction groove 117 is formed in the axial direction by digging the outer peripheral surface of the eccentric portion 108. On the upper end 108a side and the lower end 108b side of the loss reducing groove 117, seal portions 118a and 118b, respectively, in which the outer peripheral surface of the eccentric portion 108 is not dug are provided.

  FIG. 3 is an enlarged cross-sectional view near the eccentric portion 108 shown in FIG. An orbiting sliding bearing 110 is provided in the orbiting boss 109a of the orbiting scroll 109, and an eccentric part 108 of the crankshaft 103 is inserted into and engaged with the orbiting sliding bearing 110. The sliding bearing 110 slides and slides. The space enclosed between the upper end (end surface) 108a of the eccentric part 108 and the orbiting scroll 109 communicates with the oil supply hole 115, and since the upstream of the oil supply path, the pressure of the lubricating oil supplied here is The discharge pressure is almost the same.

  On the other hand, the pressure on the lower end (base end) 108b side of the eccentric portion 108 communicates with the intermediate chamber 119 having a lower pressure than the upper end 108 side, and the lubricating oil supplied from the oil supply hole 115 passes through the orbiting scroll 109. And the space surrounded by the eccentric portion 108 and the orbiting and sliding bearing 110 (the inner space of the orbiting boss portion) 4 is filled, and then discharged to the lower intermediate chamber 119 through the oil supply passage 116 and the like.

  The oil supply passage 116 is formed by a digging groove or a notch formed by digging the outer periphery of the eccentric portion 108 inward, and the oil supply passage 116 enlarges a gap between the eccentric portion 108 and the orbiting / sliding bearing 110, and The slewing bearing 110 extends across the axial direction and communicates with both the upper end 108a side and the lower end 108b side of the eccentric portion 108. Therefore, the flow resistance of the lubricating oil in the inner space 4 of the swivel boss portion flowing through the oil supply passage 116 to the intermediate chamber 119 is greater than the flow resistance of the lubricating oil flowing through a portion other than the oil supply passage 116 on the outer peripheral surface of the eccentric portion 108. Get smaller.

  On the other hand, the loss reduction groove 117 is also formed by a digging groove or a notch formed by digging the outer periphery of the eccentric portion 108 inward. The loss reduction groove 117 has an eccentricity on the upper end 108a side and the lower end 108b side. A seal portion 118 having the same diameter as the outer peripheral surface of the portion 108 is formed, and the axial length of the loss reducing groove 117 is shorter than that of the orbiting slide bearing 110. Therefore, the loss reducing groove 117 does not straddle the slewing plain bearing 110 in the axial direction, and does not open simultaneously on the upper end 108a side and the lower end 108b side of the eccentric portion 108.

  Further, in the portions of the seal portions 118 a and 118 b, the gap between the outer periphery of the eccentric portion 108 and the inner periphery of the orbiting slide bearing 110 is equal to the portion other than the oil supply passage 116 on the outer periphery of the eccentric portion 108. That is, the flow resistance flowing from the upper end 108a to the lower end 108b of the eccentric portion 108 through the loss reducing groove 117 is substantially equal to the flow resistance flowing through a portion other than the oil supply passage 116 on the outer peripheral surface of the eccentric portion 108. For this reason, the lubricating oil supplied from the oil supply hole 115 to the inner space 4 of the turning boss part preferentially passes through the oil supply passage 116 and easily flows to the intermediate chamber 119 side. In addition, the flow resistance in which the lubricating oil flows in the axial direction in the entire portion of the slewing bearing 110 is substantially the same as that in the case where the loss reduction groove 117 is not provided. Is prevented.

  4 is a cross-sectional view taken along line AA in FIG. 3, FIG. 5 is a cross-sectional view taken along line BB in FIG. 3, and FIG. 6 is a cross-sectional view taken along line CC in FIG. Since the diameter of the outer peripheral surface of the eccentric part 108 is smaller than the diameter of the inner peripheral surface of the orbiting / sliding bearing 110, there is a gap between them, and this gap is filled with lubricating oil.

  As shown in FIG. 4, the oil supply passage 116 opens at a portion of the upper end 108 a of the eccentric portion 108, and a gap between the oil supply passage 116 and the swivel bearing 110 is a portion where the oil supply passage 116 is not provided. The gap between the eccentric portion 108 and the slewing plain bearing 110 is particularly wide.

  Further, as shown in FIG. 5, in the axially intermediate portion of the eccentric portion 108, the gap between the oil supply passage 116 of the eccentric portion 108 and the swivel slide bearing 110 and the loss reduction groove 117 of the eccentric portion 108 The gap between the slewing plain bearing 110 and the slewing plain bearing 110 is particularly wider than the gap between the other part of the eccentric portion 108 and the slewing plain bearing 110.

  Further, in the vicinity of the lower end (base end) of the eccentric portion 108 in the axial direction, as shown in FIG. 6, the loss reduction groove 117 does not exist, and the portion of the oil supply passage 116 of the eccentric portion 108 and the slewing slide bearing 110 is particularly wider than the gap between the eccentric portion 108 where the oil supply passage 116 is not provided and the slewing plain bearing 110.

  FIG. 7 is a diagram for explaining the shaft rotation direction, the angular position, and the bearing load direction in the BB cross section of FIG. FIG. 7 shows the positions in the bearing load direction 121 where the swivel bearing 110 is pressed against the oil supply passage 116, the loss reduction groove 117, the rotation direction 120 of the crankshaft 103, and the eccentric portion 108. This will be described in more detail. First, the angular positions of various parts will be described using a coordinate system in which the center of the eccentric part 108 is used as a reference and the opposite side of the eccentric part 108 to the eccentric direction is 0 °.

  When the crankshaft 103 rotates in the clockwise direction as shown in the axial rotation direction 120, the orbiting scroll 109 has a resultant force of a reaction force that compresses the gas and a centrifugal force that the orbiting scroll is swung in the eccentric direction. A bearing load is generated in the bearing load direction 121. At this time, the gap between the eccentric portion 108 and the orbiting / sliding bearing 110 is not uniform in the circumferential direction but is biased, and is minimized at the minimum gap portion 122 shifted from the bearing load direction 121 to the counter-rotating direction.

The loss reduction groove 117 is provided on the outer periphery of the shaft, and the bearing loss due to oil film shearing when the shaft is slid with respect to the cylindrical sliding bearing through the lubricating oil is evaluated. The effect of reducing bearing loss was verified. The verification results are shown in FIGS. From this result, the position, depth, and width of the loss reducing groove 117 that can effectively reduce the bearing loss were examined. In this verification, the verification is performed on the assumption that the shaft diameter of the eccentric portion is 14 to 18 mm in a scroll compressor for an air conditioner.
Hereinafter, it demonstrates in detail using FIGS. 8-11.

  FIG. 8 is a diagram for explaining the starting position of the loss reducing groove 117 according to the present invention. FIG. 8A is a diagram for explaining the relationship between the starting position of the loss reducing groove 117 and the relative bearing loss, and FIG. It is a diagram explaining the relationship between the starting position of a groove | channel and a relative minimum oil film thickness.

  In the figure (a), the loss reduction groove 117 is formed by digging the outer periphery of the shaft into a digging groove, and is caused by oil film shearing when sliding is performed on the cylindrical sliding bearing through the lubricating oil. The bearing loss is shown, and the evaluation is performed by changing various circumferential start positions of the loss reducing groove 117 formed on the outer periphery of the shaft. The horizontal axis represents the circumferential start position of the loss reducing groove 117, and the vertical axis represents the relative bearing loss relative to the bearing loss when the shaft without the loss reducing groove 117 is used. The loss reducing groove 117 is a digging groove having a depth of 0.1 mm and an angular range (angular width) of 30 degrees in the circumferential direction.

  As a result of this verification, as shown in FIG. 5A, the relative bearing loss tends to decrease particularly when the starting angle of the loss reducing groove is in the range of 140 degrees to 210 degrees. Accordingly, the starting position of the loss reduction groove 117 is preferably provided in the range of 140 ° to 210 °, and by setting this range, the bearing loss can be reduced by at least 2% or more. Further, when the start position is in the range of 145 ° to 180 °, the reduction effect becomes the largest. In addition, if it is provided so that at least a part of the loss reduction groove 117 exists in the range of 140 ° to 210 °, the bearing loss reduction effect can be reduced as compared with the conventional one.

  FIG. 7B is a diagram showing the relationship between the start position of the loss reduction groove and the relative minimum oil film thickness, where the horizontal axis represents the circumferential start position of the loss reduction groove 117 and the vertical axis represents the loss reduction groove 117. The minimum oil film thickness when using a shaft without a mark is 100%, and the relative minimum oil film thickness is shown. As shown in this figure, when the starting position of the loss reducing groove 117 is 140 degrees or less, the starting position of the loss reducing groove 117 is close to the angle at which the minimum oil film thickness is obtained. If the reduction groove 117 is provided, the bearing behavior becomes unstable, and wear due to contact between the shaft and the bearing is likely to proceed. Therefore, it is preferable to determine the start position of the loss reduction groove 117 in an angle range of at least 140 degrees or more. . Note that the minimum oil film thickness is sufficiently large even when a part of the loss reduction groove 117 covers 210 degrees or more, so if the start position of the loss reduction groove 117 is in the range of 140 ° to 210 °, the end The position may be a position of 210 degrees or more.

  FIG. 9 is a diagram for explaining the relationship between the depth of the loss reducing groove 117 and the relative bearing loss in the present invention. The loss reduction groove 117 is a digging groove formed by digging the outer periphery of the shaft, and indicates a bearing loss due to oil film shear when sliding is performed on the cylindrical sliding bearing through the lubricating oil. The depth of the loss reducing groove 117 formed in (the radial depth from the outer peripheral circle of the eccentric portion before processing) was variously evaluated. The horizontal axis represents the depth of the loss reduction groove 117 (digging depth), and the vertical axis represents the bearing loss when a shaft without the loss reduction groove 117 is used as 100%, and shows the relative bearing loss relative thereto. Yes. Further, the loss reduction groove 117 was formed in an angle range (angle width) of 30 degrees in the circumferential direction, and the start angle of the loss reduction groove was 150 degrees.

  As a result of this verification, as shown in FIG. 9, the bearing loss can be reduced by at least 2% or more by setting the digging depth of the loss reducing groove to 0.002 mm or more. Further, if the depth of the loss reducing groove is 0.01 mm or more, there is at least a 5% or more bearing loss reducing effect, and if the depth of the loss reducing groove is 0.05 mm or more, the bearing loss reducing effect is the largest. Become. If the depth of the loss reducing groove 117 is excessively increased, the rigidity of the shaft is reduced. Therefore, the depth of the loss reducing groove 117 is 20% or less of the shaft diameter (the shaft diameter of the eccentric portion of the crankshaft) at the maximum. It is preferable. Therefore, in general, the depth of the loss reducing groove is preferably about 0.05 to 0.5 mm.

  FIG. 10 is a diagram illustrating the relationship between the circumferential angular width of the loss reducing groove and the relative bearing loss in the present invention. The loss reduction groove 117 is a digging groove formed by digging the outer periphery of the shaft, and indicates a bearing loss due to oil film shear when sliding is performed on the cylindrical sliding bearing through the lubricating oil. The evaluation was performed by changing the circumferential angle width of the loss reducing groove 117 formed in various ways. The horizontal axis represents the angular width in the circumferential direction of the loss reducing groove 117, and the vertical axis represents the relative bearing loss with respect to the bearing loss when the shaft without the loss reducing groove 117 is used as 100%. The depth of the loss reducing groove 117 was 0.1 mm, and the starting angle of the groove was 150 degrees.

  As a result of this verification, as shown in FIG. 10, the relative bearing loss is an angle of 10 degrees or more in the circumferential direction from the position of the starting angle 150 degrees in the circumferential direction of the loss reducing groove 117 in this example, that is, 10 degrees or more. By setting the width, the bearing loss can be reduced by at least 2%. In addition, when the loss reduction groove is gradually expanded from the starting angle 150 ° to the circumferential angle width 60 °, the relative bearing loss decreases as the circumferential angle width increases, and even if the angular width is wider than 60 °, Bearing loss shows a tendency to hardly decrease. Therefore, the angle width is preferably set in a range of 20 ° to 60 ° in consideration of workability of the bearing loss groove 117 and the like.

  As described above, when the loss reducing groove 117 is formed on the outer periphery of the eccentric portion 108 of the crankshaft 103, the angle range from 140 degrees to 210 degrees in the coordinate system shown in FIG. By providing a portion where the digging depth is 0.002 mm or more, bearing loss can be reduced. In particular, the starting position of the loss reduction groove 117 is set at an angle of about 150 degrees in the coordinate system shown in FIG. It was verified that a great bearing loss reduction effect can be obtained by setting the position, the angular width of the groove to 20 ° to 60 °, and the depth of the groove to 0.01 mm or more.

  FIG. 11 is a diagram illustrating the relationship between the rotational speed of the shaft and the relative bearing loss in the present invention. That is, it shows the bearing loss due to oil film shearing when a shaft with a loss reduction groove 117 on the outer periphery and a shaft without a loss reduction groove are slid with respect to a cylindrical bearing through lubricating oil. The evaluation was made by changing the rotational speed of the shaft in various ways. The horizontal axis in FIG. 11 is the rotational speed, and the vertical axis is the bearing loss when rotating at a rotational speed of 6000 rpm using an axis without a loss reduction groove, and the relative bearing loss relative to this is shown. Show. The loss reduction groove 117 is a digging groove having a depth of 0.1 mm, and the loss reduction groove 117 is formed in an angular range (angle width) of 30 degrees in the circumferential direction, and the start angle of the loss reduction groove is Was 150 degrees.

  As a result of this verification, as shown in FIG. 11, it was confirmed that the bearing loss was reduced at each rotation speed by providing the loss reduction groove 117. In addition, the bearing loss increases as the rotational speed increases. However, the present invention with the loss reduction groove is relatively less as the rotational speed increases than the conventional one without the loss reduction groove. It can be seen that the reduction effect is also increasing.

12 to 14 are enlarged perspective views of the vicinity of the eccentric portion showing another example of the loss reducing groove 117 provided on the outer periphery of the crankshaft.
As is apparent from FIG. 9, the loss reduction groove 117 is preferably a digging groove having a depth of 0.05 mm or more from the shaft outer peripheral surface before processing, but as shown in FIG. A notch shape may be used, and a bearing loss reduction effect that is almost the same as that in the case of the dug groove can be obtained.

  In the case of such a notch shape, the depth from the outer peripheral surface of the shaft before machining to the axial center direction continuously increases or decreases from 0 mm depending on the angular position in the circumferential direction. In order to secure a particularly large depth of 0.05 mm or more, a wider circumferential angular width is required. However, the notch shape as shown in FIG. 12 has an effect that the processing cost can be reduced as compared with the case of forming the digging groove as shown in FIG.

  In the example of FIG. 12, a seal part 118a is provided on the end face 108a side of the eccentric part in the loss reducing groove 117, and a seal part 118b is provided on the base end 108b side. It may be provided in at least one of the portions 118a and 118b. In the example shown in FIG. 13, the seal portion 118 is provided only on the base end 108 b side (intermediate chamber side) of the loss reducing groove 117. In this case, the lubricating oil flowing out from the oil supply hole 115 opened at the upper end of the eccentric portion 108 is likely to flow into the loss reduction groove 117, and the amount of oil supply increases somewhat. However, in the example of FIG. 13, even if the circumferential width of the loss reduction groove 117 is the same, the area of the loss reduction groove 117 can be increased, so that there is an advantage that the bearing loss reduction effect can be further improved. . Further, if the seal portion 118 is provided adjacent to the intermediate chamber side (base end side), an extreme increase in the amount of oil supply can be prevented.

  Further, a plurality of loss reduction grooves 117 may be formed in the circumferential direction of the eccentric portion 108 as shown in FIG. That is, when the position of 140 degrees in the anti-eccentric direction of the eccentric portion 108 in the counter-rotating direction of the crankshaft is the start position of the loss reduction groove 117 and the end position of the groove is 210 degrees, the loss reduction groove 117 The circumferential angular width is 70 degrees. When a groove having such a wide angular width is taken, a portion where the notch is not provided in the outer peripheral surface of the eccentric shaft is taken in the middle thereof, for example, with a width of about 20 degrees in the circumferential direction, as shown in FIG. The loss reduction groove 117 is divided into a loss reduction groove 117a in the range of 140 ° to 165 ° and a loss reduction groove 117b in the range of 185 ° to 210 ° at the angular position, and the loss reduction groove 117 is provided. A portion not provided with the notch is left in the range of 165 ° to 185 ° of the intermediate portion.

  The loss reduction groove 117 does not easily form an oil film pressure that supports the bearing load. However, as shown in FIG. 14, the loss reduction groove is divided into a plurality of portions in the circumferential direction. By leaving the outer circumferential surface of the eccentric shaft without forming a digging groove or notch, it is possible to secure the ability to generate oil film pressure to some extent in the portion where the outer circumferential surface of the eccentric shaft is left. As a result, even if an earthquake or a large vibration occurs and an unexpected dynamic load is applied to the portion of the loss reduction groove, the collision between the eccentric shaft 108 and the orbiting slide bearing 110 is caused. Can be prevented, and the occurrence of galling or seizure can be prevented.

  In the example shown in FIG. 14, both of the plurality of loss reduction grooves 117a and 117b, whose circumferential start positions are located around the center of the eccentric portion from the anti-eccentric direction of the eccentric portion. It is preferable that the crankshaft be provided at a position of 140 ° to 210 ° in the counter-rotating direction of the crankshaft, but at least one circumferential start position of the plurality of loss reduction grooves is a position of the 140 ° to 210 °. The bearing loss reduction effect can be obtained by providing it in

  According to the present embodiment described above, in the structure in which the outer peripheral surface of the eccentric portion of the crankshaft and the inner peripheral surface of the orbiting sliding bearing slide through the lubricating oil, the outer peripheral surface of the eccentric portion and the inner peripheral surface of the slide bearing. Since the shear resistance of the oil film due to the lubricating oil existing between the surfaces can be reduced, bearing loss during fluid lubrication can be reduced. This effect will be described in more detail.

  In general, it is known that the shear stress τ of a thin fluid lubricating oil film has a relationship of increasing with a change gradient dU / dh in the direction of the oil film thickness h in the axial rotation direction flow velocity U of the lubricating oil and the lubricating oil viscosity η. ing. According to the present embodiment, there is almost no role of supporting the load by the oil film pressure, and the digging groove is formed in the outer periphery of the eccentric shaft so that the gap between the outer periphery of the eccentric shaft and the inner periphery of the orbiting slide bearing becomes relatively small. Or it can expand by providing the loss reduction groove | channel formed by the notch. As a result, the oil film thickness h by the lubricating oil that fills the loss reduction groove can be increased, so that the change gradient dU / dh can be reduced to reduce the shear stress of the oil film. Therefore, since the shear resistance of the oil film, which is the integral value of the shear stress, is reduced, bearing loss can be reduced.

  In addition, since at least one of the end face (upper end) side and the base end (lower end) side of the eccentric part in the loss reducing groove is provided with a seal part that serves as a flow path resistance in the axial direction of the crankshaft, The loss reducing groove straddles the slewing bearing in the axial direction and does not communicate with the end face side and the base end side of the eccentric part at the same time. On the other hand, the oil supply passage is configured to communicate with the end face side and the base end side of the eccentric portion across the slewing plain bearing in the axial direction. As a result, the axial flow resistance is minimized in the oil supply passage, and the lubricating oil supplied from the oil supply hole flows preferentially in the oil supply passage. Accordingly, the lubricating oil supply state in the eccentric portion is maintained in the same manner as the conventional one not provided with the loss reduction groove, and even if the loss reduction groove is provided as in this embodiment, the amount of oil supply increases. It is possible to prevent the oiling condition from getting worse.

  In this embodiment, the start position of the loss reducing groove is provided in the angular range of 140 ° to 210 ° around the center of the eccentric shaft from the anti-eccentric direction of the eccentric portion to the counter-rotating direction of the crankshaft. It is said. As described above, if the start position of the loss reducing groove is 140 degrees or less, the generation of the oil film pressure supporting the load is hindered, the effect of reducing the bearing loss is lost, and the oil film pressure is reduced. Therefore, the oil film may be cut, so the angle is 140 degrees or more. Even when the starting position of the loss reducing groove is 210 degrees or more, since the region is a portion where the clearance between the shaft and the bearing is originally relatively large during the operation of the scroll compressor, the change gradient dU It is difficult to obtain the effect of reducing the oil film shear stress by reducing / dh and reducing the bearing loss.

  Further, in this embodiment, the loss reducing groove has a portion having a radial depth of 0.002 mm or more (preferably 0.01 to 0.05 mm or more) from the outer peripheral circle of the eccentric portion before the processing. Since it is formed to exist in the range of 140 ° to 210 ° (preferably 145 ° to 180 °) from the anti-eccentric direction of the part to the anti-rotation direction of the crankshaft, it is stable with little variation due to dimensional errors, etc. Can reduce the bearing loss.

1: Scroll compressor, 2: Sealed container, 3: Lubricating oil, 4: Space in the rotating boss part,
102: Electric motor, 103: Crankshaft, 104: Frame, 105: Main bearing,
106: lower frame, 107: auxiliary bearing,
108: eccentric part, 108a: end face (upper end), 108b: base end (lower end),
109: orbiting scroll, 110: orbiting sliding bearing,
111: Oldham ring,
112: Fixed scroll,
113: inlet
114: discharge port,
115: Refueling hole,
116: Refueling passage,
117, 117a, 117b: loss reduction grooves,
118, 118a, 118b: seal part,
119: Intermediate chamber (back pressure chamber),
120: shaft rotation direction, 121: bearing load direction,
122 Minimum gap.

Claims (9)

A fixed scroll, a turning scroll meshing with the fixed scroll,
A crankshaft having an eccentric portion at an end portion thereof for turning the orbiting scroll;
An oil supply hole penetrating the crankshaft in the axial direction and having an opening at an end face of the eccentric part;
An orbiting slide bearing that is provided on the orbiting scroll and engages and slides with an eccentric portion of the crankshaft;
An oil supply passage provided on the outer periphery of the eccentric portion of the crankshaft so as to communicate the end face side and the base end side of the eccentric portion;
In the scroll compressor configured to lubricate between the eccentric portion and the orbiting and sliding bearing with the lubricating oil supplied from the oil supply hole,
An axial loss reduction groove provided separately from the oil supply passage on the outer periphery of the eccentric portion of the crankshaft;
A scroll compressor comprising: a seal portion provided on at least one of an end face side and a base end side of the eccentric portion in the loss reducing groove.   2. The scroll compressor according to claim 1, wherein the start position of the loss reduction groove is 140 ° to 210 ° around the center of the eccentric portion from the anti-eccentric direction of the eccentric portion to the counter-rotating direction of the crankshaft. A scroll compressor characterized by being provided at the position of.   3. The scroll compressor according to claim 2, wherein the start position of the loss reduction groove is 145 ° to 180 ° around the center of the eccentric portion from the anti-eccentric direction of the eccentric portion to the counter-rotating direction of the crankshaft. A scroll compressor characterized by being provided at the position of.   3. The scroll compressor according to claim 2, wherein the oil supply passage and the loss reduction groove are each formed by an excavation groove or a notch on an outer periphery of the eccentric portion, and the loss reduction groove is processed. A scroll compressor characterized in that a portion having a radial depth of 0.002 mm or more from the previous outer peripheral circle of the eccentric portion exists.   5. The scroll compressor according to claim 4, wherein the depth of the loss reducing groove is 0.01 mm or more and 20% or less of the shaft diameter of the eccentric portion.   6. The scroll compressor according to claim 5, wherein the loss reducing groove has a depth of 0.05 to 0.5 mm.   2. The scroll compressor according to claim 1, wherein a plurality of the loss reduction grooves are formed in a circumferential direction of the eccentric portion.   8. The scroll compressor according to claim 7, wherein at least one of the plurality of loss reduction grooves formed around the center of the eccentric portion is opposite to the crankshaft from the eccentric direction of the eccentric portion. A scroll compressor characterized by being provided at a position of 140 ° to 210 ° in the rotational direction.   2. The scroll compressor according to claim 1, wherein the seal portion is provided at least on a proximal end side of the eccentric portion in the loss reducing groove.

Images