JP4859730B2 - Scroll compressor - Google Patents

Description

  The present invention relates to a scroll compressor mounted on an air conditioner, a water heater, a refrigerator, or the like.

The scroll compressor includes a radial bearing that supports a shaft that transmits a driving force to a compression mechanism unit in order to compress gas, and a thrust bearing that supports an axial compression reaction force.
In order to prevent sliding loss, adhesion, and seizure in a thrust bearing during operation in a conventional scroll compressor, a thrust bearing that receives an axial thrust force generated during gas compression, and a frame that supports the thrust bearing When the thrust bearing receives a thrust force, a gap is formed on the inner periphery of the thrust bearing so that the thrust bearing can be deformed, and the thrust bearing is bent in accordance with the deformation of the orbiting scroll base plate. There is one that is prevented from receiving (see, for example, Patent Document 1).

JP-A-57-173585 (page 2-3, FIG. 3)

  The invention of Patent Document 1 is an abnormality that occurs because a thrust load is locally received by bending the thrust base plate following the deformation of the base plate of the orbiting scroll even under an operating condition in which the thrust load is excessive. Wear and seizure can be prevented. However, when a refrigerant whose operating cycle is extremely high in pressure compared to conventional refrigerants, such as carbon dioxide, is used, the deflection of the base plate of the orbiting scroll becomes very large due to an increase in the thrust load. The base plate also bends along with it, but unlike the slides close to the planes seen with ordinary bearings, the base plate of the orbiting scroll and the thrust bearing slide on the curved surfaces that are greatly deflected from each other. The sliding area may be reduced and seizure may occur, and cannot be adequately handled.

  In addition, it is very difficult to determine the shape and dimensions considering the mutual deformation of the base plate of the orbiting scroll and the thrust bearing of the frame, and local contact occurs at the outer peripheral part and inner peripheral part of the thrust bearing. There was a problem that it was extremely lowered. In particular, if the rigidity and material of the base plate of the orbiting scroll and the thrust bearing of the frame are extremely different (generally, the orbiting scroll revolves with a motor during the refrigerant compression process, and its centrifugal force is the cause of vibration and noise. Therefore, thrust bearings are often made of castings from the viewpoint of processing and cost, and are often made of cast scrolls or thrust bearings. The influence of deformation on the shape was great, and it was extremely difficult to determine the thickness dimension.

  The present invention has been made in order to solve the above-described problems. A highly reliable bearing portion that does not cause seizure or the like even under a refrigerant whose operating cycle is high pressure and wide, such as carbon dioxide, is obtained. An object of the present invention is to provide a scroll compressor provided.

The scroll compressor according to the present invention has a fixed scroll having spiral teeth on the lower surface, and a spiral tooth having a compression chamber formed on the upper surface of the base plate in combination with the spiral teeth of the fixed scroll. An oscillating scroll provided with a oscillating bearing at the center of the lower surface and an oil hole provided in the axial direction, and an eccentric shaft provided at the upper part is engaged with the front oscillating bearing to drive the driving force of the driving means. A main shaft that transmits to the dynamic scroll, a concave portion that is fixed to the shell and accommodates the rocking bearing of the rocking scroll at the bottom, and a main bearing that rotatably supports the main shaft at the bottom of the concave portion, A substantially cylindrical bottomed top is provided with a gap formed in the bottom part over the entire circumference from the inner peripheral surface to the outer periphery of the concave part, and a thrust bearing part for axially supporting the orbiting scroll is formed by the upper part of the gap. Frame and said orbiting scroll Preventing rotation and a rotation preventing means for revolving the spindle around it,
The outer diameter, thickness and longitudinal elastic modulus of the base plate of the orbiting scroll are D ₁ , t ₁ and E ₁ , respectively, and the inner diameter, thickness and longitudinal elastic modulus of the thrust bearing portion are D ₂ , t ₂ and E respectively. ₂ and the inner diameter of the gap is D ₃ , 5 mm ≦ t ₁ ≦ 20 mm, 50 mm ≦ D ₁ ≦ 200 mm, 0.8 ≦ D ₁ / D ₃ ≦ 1.4, D ₂ / D ₃ ≦ 0. 6, 1.0 ≦ (t ₁ / t ₂ ) × (E ₁ / E ₂ ) ≦ 2.2.

  The present invention relates to a conventional scroll compressor in which a thrust bearing is simply deformed during operation while the base plate of the orbiting scroll is deformed. In order to solve the problem that the sliding surface area of the rocking scroll base plate and the thrust bearing is reduced and seizure occurs, etc., caused by using the refrigerant that becomes The position of the contact surface between the scroll base plate and the thrust bearing portion is defined, and the base plate and the thrust bearing portion of the orbiting scroll are configured based on the dimensions and the longitudinal elastic modulus based thereon. As a result, seizure on the sliding surface on which the deformed curved surfaces of the base plate of the orbiting scroll and the thrust bearing portion slide can be prevented, and an appropriate surface pressure on the sliding surface over the entire operating pressure range can be obtained. Since it can hold | maintain, the scroll compressor provided with the highly reliable bearing part can be obtained.

FIG. 1 is a cross-sectional view of a main part of a scroll compressor according to an embodiment of the present invention.
An oil sump (not shown) in which lubricating oil is stored is provided at the bottom of the shell 1 on the cylinder whose top and bottom are closed, and a fixed scroll 2 having spiral teeth 4 on the bottom surface of the base plate 3 at the top. And a swing scroll 5 having a spiral tooth 7 which forms a compression chamber 10 in combination with the spiral tooth 4 of the fixed scroll 2 on the upper surface of the base plate 6, and a swing bearing 9 projects from the center of the lower surface. Is arranged.

  11 is an upper frame of a substantially bottomed cylindrical shape fixed to the upper part of the shell 1 and coupled with a fixed scroll 2, and has a recess 14 at the center of the thrust base plate 13 which is the bottom of the cylindrical part 12. The thrust base plate 13 is provided with a substantially donut-shaped air gap 15 (groove) formed radially from the inner peripheral surface of the recess 14 toward the outer peripheral side. A thrust bearing portion 16 that is supported in the axial direction is formed. Reference numeral 18 denotes a main bearing provided in the lower part of the recess 14. The orbiting scroll 5 has its orbiting bearing 9 inserted into the recess 14 of the upper frame 11 and accommodated in the cylindrical portion 12, and is supported on the thrust bearing portion 16 so as to be able to swing. Reference numeral 19 denotes an Oldham ring which is provided on the base plate 6 of the orbiting scroll 5 and is a rotation preventing means for preventing the orbiting scroll 5 from rotating and revolving around a main shaft 20 described later.

  Reference numeral 20 denotes a main shaft having an oil hole 21 in the axial direction of the central portion. The upper portion is a main bearing 18 of the upper frame 11, and the lower portion is a bearing (not shown) provided on a lower frame installed above the oil sump. An eccentric shaft portion 22 that is rotatably supported and is provided on the upper portion is locked to the rocking bearing 9. The lower part is connected to an oil pump and transmits the driving force of a driving means (not shown) to the orbiting scroll 5.

  Although the case where the thrust bearing portion 16 is formed integrally with the upper frame 11 has been described in the above description, it may be configured as a separate member. Further, the width of the gap 15 in the axial direction is sufficient as long as the allowance for the thrust bearing portion 16 can be secured (for example, about 0.1 mm), but it may be larger than that in processing and molding.

In the present invention, as shown in FIG. 2, the outer diameter of the base plate 6 of the rocking scroll 5 is D ₁ , the wall thickness is t ₁ , the longitudinal elastic modulus is E _1, and the inner diameter of the thrust bearing portion 16 is When D ₂ , the wall thickness is t ₂ , the longitudinal elastic modulus is E _2, and the inner diameter of the gap 15 is D ₃ , 5 mm ≦ t ₁ ≦ 20 mm, 50 mm ≦ D ₁ ≦ 200 mm, 0.8 ≦ D ₁ / D _{When 3} ≦ 1.4 and D ₂ / D ₃ ≦ 0.6, 1.0 ≦ (t ₁ / t ₂ ) × (E ₁ / E ₂ ) ≦ 2.2 is set.

In the scroll compressor configured as described above, when the driving means is energized and the main shaft 20 is rotationally driven, the orbiting scroll 5 which is connected to this and is prevented from rotating by the Oldham ring 19 and performs a revolving motion is thrust. Oscillating motion is performed along the bearing portion 16. The refrigerant gas introduced into the shell 1 from the refrigerant suction pipe is guided to the compression chamber 10 formed by the spiral teeth 4 and 7 of the fixed scroll 2 and the swing scroll 5, and the swing scroll 5 swings. The volume is reduced and compressed, and is discharged out of the shell 1 from the refrigerant discharge pipe.
At the same time, the oil pump is driven by the main shaft 20, and the lubricating oil in the oil sump is sent from the oil hole 21 of the main shaft 20 to the recess 14 to lubricate each sliding portion and return to the oil sump again.

  At this time, the base plate 6 of the orbiting scroll 5 is deformed into a concave shape by the compression reaction force of the refrigerant gas that has entered the compression chamber 10, but the thrust bearing portion 16 of the upper frame 11 is also formed in the gap 15 provided in the upper frame 11. As a result, the base plate 6 is deformed to generate a force for supporting the orbiting scroll 5 in the axial direction (thrust direction). And the place where the mutual force balances becomes a contact surface and balances, and the orbiting scroll 5 continues the oscillation motion as it is. Therefore, the upper surface 17 of the thrust bearing portion 16 and the lower surface 8 of the base plate 6 of the orbiting scroll 5 become contact surfaces.

  In this way, during operation, the lower surface 8 of the base plate 6 of the orbiting scroll 5 and the upper surface 17 of the thrust bearing portion 16 become sliding surfaces, but oil supply means (oil sump, oil pump) provided in the shell 1 are used. The lubricating oil sent by the oil holes 21 of the main shaft 20 is always present in each bearing portion. Therefore, normally, an oil film is always formed on the bearing surface that receives the thrust load due to the compression reaction force of the refrigerant gas, and the sliding is thereby performed smoothly, so that the bearing portion does not seize.

  As described above, there is lubricating oil in each bearing portion, and it enters a slight gap between the lower surface 8 of the base plate 6 of the orbiting scroll 5 and the upper surface 17 of the thrust bearing portion 16, and FIG. In order to form an oil film, as shown in FIG. The maximum gap in which the oil film is formed is said to be several microns, and the portion where the oil film is formed is generally considered as the pressure receiving area. Further, at this time, assuming that the radial position where the minimum gap is formed is the pressure receiving action point, the maximum oil film reaction force is obtained at the position of the diameter D, and the hydraulic reaction force distribution as shown is obtained.

  When the thrust load is increased under certain operating conditions, the positions of the pressure receiving action points of the base plate 6 of the rocking scroll 5 and the thrust bearing portion 16 are moved inward (center side). Considering the bending state of the base plate 6 of the orbiting scroll 5 and the thrust bearing portion 16 at that time, as shown in FIG. 9, the bending amount deflection angle increases toward the outer peripheral side. Therefore, not only the position of the sliding surface shifts inward, but also the gap between the two increases toward the outer periphery due to bending, so no oil film reaction force is generated in the gap of several microns or more where an oil film can be formed. . Thus, since the area where the oil film can be formed decreases, the surface pressure increases greatly, and seizure is likely to occur.

  On the other hand, when the thrust load is reduced, the base plate 6 of the orbiting scroll 5 is less deformed, the amount of deflection between the base plate 6 of the orbiting scroll 5 and the thrust bearing portion 16 is reduced, and the pressure receiving action point is reduced. As shown in FIG. 10, not only the position of the sliding surface shifts to the outside, but also the gap becomes smaller and the area where the oil film is formed becomes larger. The area due to the increase also becomes relatively large, and the pressure receiving area increases. Thereby, since surface pressure falls, it becomes difficult to produce seizing.

  From the above, since the deformation of the base plate 6 and the thrust bearing portion 16 of the orbiting scroll 5 is large and the pressure receiving area that supports the thrust load is smaller is the most severe sliding condition, It is necessary to ensure an appropriate surface pressure even under an overload operation condition where the load and sliding conditions are maximum values. Thereby, the surface pressure in other operation ranges can be suppressed, and the reliability of the bearing portion can be ensured over the entire operation pressure.

Next, functions and effects of the present invention will be described. The outer diameter, thickness, and longitudinal elastic modulus of the base plate 6 of the orbiting scroll 5 are D ₁ , t ₁ , E ₁ , respectively, and the inner diameter, thickness, and longitudinal elastic modulus of the thrust bearing portion 16 are D ₂ , respectively. t ₂ , E ₂ , the inner diameter of the gap 15 provided in the upper frame 11 is D ₃ , and the diameter of the pressure receiving action point of the base plate 6 of the rocking scroll 5 and the thrust bearing portion 16 is D. FIG. 3 shows the relationship between the rigidity ratio (t ₁ / t ₂ ) × (E ₁ / E ₂ ) between the base plate 6 of the dynamic scroll 5 and the thrust bearing portion 16 and D / D ₃ . Here, the parameters governing the deflection angle of the base plate 6 and thrust bearing portion 16 of the orbiting scroll 5 are the thicknesses t ₁ and t _{2 in} the axial direction and the longitudinal elastic modulus E ₁ and E ₂ . Therefore, (t ₁ / t ₂ ) × (E ₁ / E ₂ ) was defined as the rigidity ratio.

FIG. 3 shows the diameter of the pressure receiving action point of the base plate 6 of the orbiting scroll 5 and the thrust bearing portion 16 when a thrust load corresponding to the overload operation acts on the orbiting scroll 5 and the base plate 6 is deformed. D is calculated by analysis. The base plate 6 of the orbiting scroll 5 is often designed in the range of 5 mm ≦ t ₁ ≦ 20 mm and 50 mm ≦ D ₁ ≦ 200 mm in terms of machining and the size and rigidity of the shell 1, In the thrust bearing portion 16 (flexible structure portion), 0.8 ≦ D ₁ / D ₃ ≦ 1.4, D ₂ / D ₃ due to the relationship between the revolution radius of the orbiting scroll 5 and the retractability of the orbiting bearing 9. Since it is often designed in the range of ≦ 0.6, 5 mm ≦ t ₁ ≦ 20 mm, 50 mm ≦ D ₁ ≦ 200 mm, 0.8 ≦ D ₁ / D ₃ ≦ 1.4, D ₂ / D ₃ ≦ 0 The calculation result of .6 is shown.

The solid line in the figure is an approximate curve, and D / D ₃ decreases as the rigidity ratio between the base plate 6 and the thrust bearing portion 16 of the orbiting scroll 5 decreases. When the rigidity ratio is reduced, the rigidity of the thrust bearing portion 16 becomes larger than the rigidity of the base plate 6 of the orbiting scroll 5, so that the inner peripheral side (center side) of the thrust bearing portion 16 is less bent and stretched. Further, a tendency of causing a contact phenomenon on the inner peripheral side of the base plate 6 of the swing scroll 5 is observed.

In the region where D / D ₃ is very small as described above, the pressure receiving point between the base plate 6 of the orbiting scroll 5 and the thrust bearing portion 16 is extremely close to the inner peripheral side of the thrust bearing portion 16. As shown in FIG. 4, it is considered that this can occur when (the rigidity of the base plate 6 of the orbiting scroll 5) << (the rigidity of the thrust bearing portion 16). Therefore, the area for supporting the thrust load is small, the surface pressure on the sliding surface is extremely increased, and there is a possibility that local seizure due to metal contact or the like occurs due to oil shortage.

On the other hand, in the region where D / D ₃ is extremely large, the pressure receiving action points of the base plate 6 and the thrust bearing portion 16 of the orbiting scroll 5 move to the outer peripheral side and are extremely close to the inner diameter D _{3 of the} gap 15. As shown in FIG. 5, it is considered that this can occur when (the rigidity of the base plate 6 of the orbiting scroll 5) >> (the rigidity of the thrust bearing portion 16). Also in this case, the area for supporting the thrust load becomes small, and local seizure may occur.
Therefore, as shown in FIG. 6, it is desirable that the base plate 6 and the thrust bearing portion 16 of the orbiting scroll 5 are deformed so as to follow each other.

Therefore, the limit of occurrence of local wear of the rigidity ratio (t ₁ / t ₂ ) × (E ₁ / E ₂ ) between the base plate 6 of the rocking scroll 5 and the thrust bearing portion 16 was obtained by experiments. In the experiment, continuous operation was performed under an overload condition using the wall thickness t ₂ of the thrust bearing 16 as a parameter, and the operation was performed for 2000 hours at the contact position between the two by analysis (although there was some variation in the evaluation time, the progress of wear occurred). Used as a measure of convergence) and the amount of wear after completion was measured.

FIG. 7 shows the ratio of the wear amount when the wear amount of D / D ₃ = 0.7 is used as a reference.
In FIG. 7, when D / D ₃ <0.65, the amount of wear is very large, and as shown in FIG. 4, it is at the extreme pressure bearing point position on the inner peripheral side of the thrust bearing portion 16. it is conceivable that. On the other hand, when 0.8 <D / D ₃ , it is considered that the pressure receiving action point position is as shown in FIG. 5, but the wear amount gradually increases, compared with the case of D / D ₃ <0.65. The absolute amount of wear is small. This is considered to be because the surface pressure is suppressed small because the position of the pressure receiving point is longer on the outer peripheral side of the thrust bearing portion 16 than on the inner peripheral side and the contact surface area is large.

And it is thought that the amount of wear is the smallest in the vicinity of 0.7 ≦ D / D ₃ ≦ 0.9, and an appropriate contact surface pressure can be secured. When these are compared with the approximate line in FIG. 3, 0.7 ≦ D / D ₃ ≦ 0.9, that is, 1.0 ≦ (t ₁ / t ₂ ) × (E ₁ / E ₂ ) ≦ 2. It can be seen that an appropriate surface pressure can be secured in the range of 2.

As is apparent from the above description, when 1.0 ≦ (t ₁ / t ₂ ) × (E ₁ / E ₂ ) ≦ 2.2, as shown in FIG. Since the base plate 6 of the orbiting scroll 5 and the thrust bearing portion 16 are bent over each other and the contact surface area can be increased so as to obtain an appropriate surface pressure, the wear resistance and seizure resistance are excellent. A high bearing part can be obtained.

  The scroll compressor according to the present invention sets the dimensions of the base plate 6 and the thrust bearing portion 16 of the orbiting scroll 5 and the longitudinal elastic modulus of the material constituting the same as described above, thereby allowing the oscillation in the thrust bearing portion 16 to be adjusted. Since an appropriate surface pressure can be maintained for the sliding surface contact with the base plate 6 of the dynamic scroll 5, it is possible to prevent a significant sliding loss and seizure due to local contact in the thrust bearing portion 16, and to be reliable. A scroll compressor provided with a highly reliable bearing portion can be obtained. In addition, although the material of the rocking scroll 5 and the thrust bearing portion 16 is not particularly specified, if an aluminum-based material or a cast iron-based material is used, an effect can be obtained in terms of workability and cost.

It is sectional drawing of the principal part of the scroll compressor which concerns on one embodiment of this invention. It is explanatory drawing which shows the dimensional relationship of the principal part of FIG. It is a diagram which shows the relationship between the rigidity ratio of the base plate and thrust bearing part of the rocking | scrolling scroll which concerns on this invention, and the position of a contact surface. It is explanatory drawing which shows the relationship between the baseplate of a rocking | scrolling scroll at the time of an overload driving | operation, and a thrust bearing part. It is explanatory drawing which shows the relationship between the baseplate of a rocking | scrolling scroll at the time of an overload driving | operation, and a thrust bearing part. It is explanatory drawing which shows the relationship between the baseplate of a rocking | scrolling scroll at the time of an overload driving | operation, and a thrust bearing part. It is a diagram which shows the relationship between the position of the contact surface of the base plate of a rocking | fluctuation scroll, and a thrust bearing part at the time of a driving | operation, and the amount of wear. It is a conceptual diagram which shows the pressure receiving area of the base plate of a rocking scroll, and a thrust bearing part. It is explanatory drawing which shows the relationship between the pressure-receiving action point of the base plate of a rocking scroll, a thrust bearing part, and a pressure-receiving area at the time of a driving | operation. It is explanatory drawing which shows the relationship between the pressure-receiving action point of the base plate of a rocking scroll, a thrust bearing part, and a pressure-receiving area at the time of a driving | operation.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Shell, 2 Fixed scroll, 4,7 Spiral tooth, 5 Swing scroll, 6 Base plate, 9 Swing bearing, 10 Compression chamber, 11 Upper claim, 14 Recess, 15 Space | gap, 16 Thrust bearing part, 18 Main bearing, 19 Oldham ring, 20 spindle, 21 oil hole, 22 eccentric shaft.

Claims (4)

A fixed scroll having spiral teeth on the lower surface, and a spiral tooth formed on the upper surface of the base plate in combination with the spiral teeth of the fixed scroll to form a compression chamber, and a rocking bearing is provided at the center of the lower surface of the base plate An orbiting scroll
An oil hole is provided in the axial direction, and an eccentric shaft portion provided at the upper portion is engaged with the front rocking bearing to transmit the driving force of the driving means to the rocking scroll;
A concave portion that is fixed to the shell and accommodates the rocking bearing of the rocking scroll at the bottom; and a main bearing that rotatably supports the main shaft at a lower portion of the concave portion, and an inner peripheral surface of the concave portion at the bottom A generally bottomed cylindrical upper frame in which a gap is provided over the entire circumference from the outer circumference to the outer circumference, and a thrust bearing portion is formed by the upper part of the gap to support the rocking scroll in the axial direction;
Rotation prevention means for preventing rotation of the rocking scroll and revolving around the main shaft,
The outer diameter, thickness and longitudinal elastic modulus of the base plate of the orbiting scroll are D ₁ , t ₁ and E ₁ , respectively, and the inner diameter, thickness and longitudinal elastic modulus of the thrust bearing portion are D ₂ , t ₂ and E respectively. ₂ and the inner diameter of the gap is D ₃ , 5 mm ≦ t ₁ ≦ 20 mm, 50 mm ≦ D ₁ ≦ 200 mm, 0.8 ≦ D ₁ / D ₃ ≦ 1.4, D ₂ / D ₃ ≦ 0. 6, a scroll compressor characterized in that 1.0 ≦ (t ₁ / t ₂ ) × (E ₁ / E ₂ ) ≦ 2.2.   2. The scroll compressor according to claim 1, wherein the thrust bearing portion is constituted by a member separate from the upper frame.   3. The scroll compressor according to claim 1, wherein the swing scroll and the thrust bearing portion are made of an aluminum-based material or a cast iron-based material.   The scroll compressor according to any one of claims 1 to 3, wherein the gas to be compressed is carbon dioxide.

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