Scroll compressor

Abstract

The invention provides a scroll compressor, which can effectively inhibit strong contact between a scroll wrap of a movable scroll plate and a cover plate of a fixed scroll plate without compromising functions, and can improve durability. A compression chamber (34) formed between scroll teeth (24, 32) of each of a fixed scroll (21) and a movable scroll (22) is moved while narrowing from the outside toward the inside, and a working fluid is compressed. The wrap (32) of the movable scroll (22) has an inclined portion that gradually decreases in height toward a winding end point (P2) in a range from a point (P1) at which a line (L1) extending outward through an outer wall opening start point (S) from the center (O) of a vortex base circle intersects with the outermost wrap (32) to the winding end point (P2).

Description

Technical Field

[0001] The present invention relates to a scroll compressor that compresses a working fluid in a compression chamber formed between wraps of two scrolls by causing a movable scroll to orbit relative to a fixed scroll. Background Art

[0002] In the past, this type of scroll compression mechanism has become a compression mechanism composed of a fixed scroll and a movable scroll, wherein the fixed scroll has a spiral vortex tooth on the surface of a cover plate, and the movable scroll has a spiral vortex tooth on the surface of a cover plate, and the spiral teeth of each scroll are opposed to each other to form a compression chamber between the spiral teeth, and a motor is used to make the movable scroll revolve relative to the fixed scroll, thereby reducing the volume of the compression chamber from the outside to the inside while moving, thereby compressing the working fluid (refrigerant).

[0003] In this case, a tip seal of resin material was installed at the top of the spiral teeth of both the fixed scroll and the movable scroll or at one of them to prevent the metal (aluminum) from contacting each other. However, without a tip seal, in the operation state where the scroll compressor repeatedly stops and restarts, since the movable scroll starts while tipping over (tilting), it is believed that until the startup is stable, the tip of the spiral teeth of the movable scroll will contact the cover plate of the fixed scroll very strongly, especially near the winding terminal where the wall thickness of the spiral teeth is thin and the surface pressure is easy to rise, forming a groove caused by drag on the cover plate of the fixed scroll.

[0004] If this state is repeated, the plating layer at the tip of the movable scroll near the winding terminal end is worn, and strong contact resistance is generated between the metal scrolls, causing fatigue failure (cracks and breaks) due to load.

[0005] Patent Document 1: Japanese Patent No. 4545039

[0006] Therefore, although it is conceivable to lower the wrap terminal end portion of the movable scroll in a stepped manner, for example, there is a disadvantage that the surface pressure at the corner of the step joint increases, inducing local peeling of the plating layer.

[0007] In addition, for example, it is possible to gradually reduce the outermost height of the spiral tooth of the movable scroll as in Patent Document 1. However, Patent Document 1 does not clearly state the range of reducing the height of the spiral tooth. If the range is too large, the function as a scroll compressor will be impaired. On the other hand, if the range is too small, it cannot cope with the actual wear of the scroll, and the occurrence of a strong contact state cannot be effectively suppressed, which will impair durability. Summary of the invention

[0008] The present invention is completed to solve the above-mentioned existing technical problems, and its purpose is to provide a scroll compressor that can effectively suppress the strong contact between the spiral teeth of the movable scroll and the cover plate of the fixed scroll without damaging the function, thereby improving the durability.

[0009] The scroll compressor of the present invention has a compression mechanism composed of a fixed scroll and a movable scroll, wherein the fixed scroll and the movable scroll have spiral vortex teeth formed on the respective surfaces of their respective cover plates, respectively, and the working fluid is compressed by making the movable scroll revolve relative to the fixed scroll and making the compression chamber formed between the respective vortex teeth of the two scrolls shrink from the outside toward the inside while moving, wherein the vortex teeth of the movable scroll have an inclined portion, and the inclined portion gradually decreases in height toward the winding end point P2 within a range from the point P1 where a line L1 extending from the center of the vortex base circle through the outer wall and the starting point toward the outside intersects with the outermost vortex tooth to the winding end point P2.

[0010] The scroll compressor of the invention of method 2 is based on the above invention, and the spiral tooth of the movable scroll plate is continuously formed within the said range with a first inclined portion whose height gradually decreases toward the winding end point P2, a flat portion with a constant height, and a second inclined portion whose height gradually decreases toward the winding end point P2.

[0011] In the scroll compressor according to the third aspect of the invention, in the above invention, the height of the lap of the movable scroll is reduced by 10 μm at the terminal end of the first inclined portion and by 50 μm at the terminal end of the second inclined portion.

[0012] A scroll compressor according to a fourth aspect of the invention is characterized in that, in the second aspect of the invention, the length of the lap of the movable scroll is set to be longer in the flat portion than in the first inclined portion, and longer in the second inclined portion than in the flat portion.

[0013] A scroll compressor according to a fifth aspect of the invention is the scroll compressor according to the first aspect of the invention, wherein two types of scrolls are subjected to plating treatment.

[0014] A scroll compressor according to a sixth aspect of the invention is characterized in that, in addition to the first aspect of the invention, a back pressure chamber is formed on the back side of the cover plate of the movable scroll, and a back pressure hole is formed through the cover plate of the movable scroll to connect the back pressure chamber with the compression chamber.

[0015] The scroll compressor according to the invention of aspect 7 is based on the above-mentioned inventions, in which no tip seal is provided at the lap tips of the fixed scroll and the movable scroll.

[0016] According to the present invention, while maintaining the function as a scroll compressor, the drag of the cover plate of the fixed scroll is improved, and fatigue damage near the winding terminal of the volute of the movable scroll can be effectively prevented, thereby improving durability. Thus, a scroll compressor that takes both function and durability into consideration can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a longitudinal sectional view of a scroll compressor according to an embodiment of the present invention. Figure 2 yes Figure 1 A top view of a movable scroll of a scroll compressor as viewed from the wrap side. Figure 3 Yes Description Figure 2 A diagram of the height of the spiral wrap near the winding terminal of the movable scroll. DETAILED DESCRIPTION

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 This is a schematic cross-sectional view of a scroll compressor 1 according to an embodiment of the present invention.

[0019] The scroll compressor 1 of the embodiment is a so-called horizontally mounted inverter-integrated scroll compressor, which is used, for example, in a refrigerant circuit of an air-conditioning device for an electric vehicle, and sucks in a refrigerant as a working fluid of the air-conditioning device, compresses the refrigerant and discharges it to a discharge pipe. The scroll compressor 1 includes a three-phase electric motor 2, an inverter 3 for operating the electric motor 2, and a scroll compression mechanism 4 as a compression mechanism driven by the electric motor 2.

[0020] The scroll compressor 1 of the embodiment comprises: a stator housing 7, which accommodates an electric motor 2 and a central housing 6 on the inside; an inverter box 8, which is installed on the end wall 7A on one end side of the stator housing 7 and accommodates the inverter 3 on the inside; and a rear housing 9, which is installed on the other end side of the stator housing 7.

[0021] The stator housing 7, the inverter case 8 and the rear housing 9 are all made of metal (aluminum in the embodiment), and are joined together to form a housing 11 of the scroll compressor 1 of the embodiment.

[0022] A motor chamber 12 for accommodating the electric motor 2 is formed in the stator housing 7, and one end face of the motor chamber 12 is basically closed by the end wall 7A of the stator housing 7. And the end wall 7A serves as a partition wall that divides the motor chamber 12 and the inverter accommodating portion 13 described later. The other end face of the motor chamber 12 is open, and after the electric motor 2 is accommodated in the opening, the central housing 6 is accommodated. In addition, a sub-bearing 16 is mounted on the inner surface (motor chamber 12 side) of the end wall 7A, and the sub-bearing 16 is used to support one end of the drive shaft 14 of the electric motor 2 so that it can rotate.

[0023] The central casing 6 has an opening on the side opposite to the electric motor 2 (the other end side), and after accommodating a movable scroll 22 of the scroll compression mechanism 4, the opening is closed by being fixed to the stator casing 7 through a rear casing 9 to which a fixed scroll 21 of the scroll compression mechanism 4, which is described later, is fixed.

[0024] In addition, a through hole 17 is opened in the central housing 6 for the other end of the driving shaft 14 of the electric motor 2 to pass through, and a main bearing 18 is installed on the side of the scroll compression mechanism 4 of the through hole 17 and in the central housing 6. The main bearing 18 supports the other end of the driving shaft 14 on the side of the scroll compression mechanism 4 so that it can rotate.

[0025] The electric motor 2 is composed of a stator 25 on which a coil is wound and fixed to the inner side of the peripheral wall of the stator housing 7, and a rotor 23 that rotates inside the stator 25. And, for example, the inverter 3 converts a direct current from a battery (not shown) of the vehicle into a three-phase alternating current and supplies it to the coil of the stator 25 of the electric motor 2, so that the rotor 23 is driven to rotate. And the drive shaft 14 is fixed to the rotor 23.

[0026] In addition, the stator housing 7 is formed with a suction port 20, and the refrigerant sucked from the suction port 20 flows into the center housing 6 after passing through the electric motor 2 in the stator housing 7, and is then sucked into the suction portion 37 outside the scroll compression mechanism 4. Thus, the electric motor 2 is cooled by the sucked refrigerant. In addition, the refrigerant compressed by the scroll compression mechanism 4 is configured to pass through the discharge port 30 formed in the rear housing 9, and is discharged from the discharge chamber 27 described later to the discharge piping of the refrigerant circuit outside the housing 11, which is not shown.

[0027] The scroll compression mechanism 4 is composed of the aforementioned fixed scroll 21 and movable scroll 22. The fixed scroll 21 is integrally provided with a disc-shaped cover plate 23 and a spiral wrap 24 formed by an involute shape or a curve approximating the involute shape and uprightly provided on the surface (one surface) of the cover plate 23, and the surface of the cover plate 23 on which the wrap 24 is uprightly provided is fixed to the rear housing 9 as the center housing 6 side.

[0028] In addition, no tip seal is provided at the tip of the volute 24 of the fixed scroll 21 of the embodiment. In addition, in the embodiment, tin plating is applied to the surface of the cover plate 23 and the volute 24. A discharge hole 26 is formed in the center of the cover plate 23 of the fixed scroll 21, and the discharge hole 26 is connected to the discharge chamber 27 in the rear housing 9. In the figure, 28 is a discharge valve, and the discharge valve 28 is provided at the opening of the discharge hole 26 located on the back side (the other side) of the cover plate 23.

[0029] The movable scroll 22 is a scroll that revolves relative to the fixed scroll 21, and integrally comprises: a disc-shaped cover plate 31; a spiral volute 32 that is upright on the surface (one surface) of the cover plate 31 and is in the shape of an involute or a curve that is approximately the involute; and a boss 33 that protrudes from the center of the back side (the other surface) of the cover plate 31.

[0030] In addition, a tip seal is not provided at the tip of the volute 32 of the movable scroll 22 of the embodiment. In addition, in the embodiment, chemical nickel-phosphorus plating is performed on the surface of the cover plate 31 and the volute 32. The movable scroll 22 is arranged in such a manner that the volute 32 protrudes in the direction of the fixed scroll 21, the volute 32 and the volute 24 of the fixed scroll 21 are opposite and meshed with each other, and a pressure chamber 34 is formed between each volute 24, 32.

[0031] That is, the volute 32 of the movable scroll 22 is opposed to the volute 24 of the fixed scroll 21, and meshes with each other in a manner that the top end of the volute 32 contacts the surface of the cover plate 23 and the top end of the volute 24 contacts the surface of the cover plate 31, and an eccentric portion 36 is fitted in the boss 33 of the movable scroll 22, and the eccentric portion 36 is eccentrically arranged from the axis at the other end of the drive shaft 14. Moreover, if the drive shaft 14 rotates together with the rotor 23 of the electric motor 2, the movable scroll 22 does not rotate on its own, but revolves relative to the fixed scroll 21.

[0032] Since the movable scroll 22 revolves eccentrically relative to the fixed scroll 21, the eccentric directions and contact positions of the volutes 24 and 32 move while rotating, and the pressure chamber 34 that sucks the refrigerant from the suction portion 37 on the outside gradually shrinks while moving inward. As a result, the refrigerant is continuously compressed and finally discharged from the discharge hole 26 in the center through the discharge valve 28 to the discharge chamber 27.

[0033] exist Figure 1, 38 is an annular thrust plate. The thrust plate 38 is used to divide the back pressure chamber 39 formed between the back side of the cover plate 31 of the movable scroll 22 and the central housing 6 and the suction portion 37 on the outside of the scroll compression mechanism 4, and is located outside the boss 33 and between the central housing 6 and the movable scroll 22. In addition, 41 is a sealing material installed on the back side of the cover plate 31 of the movable scroll 22 and abutting against the thrust plate 38, and the back pressure chamber 39 and the suction portion 37 are divided by the sealing material 41 and the thrust plate 38.

[0034] In addition, reference numeral 48 denotes a centrifugal oil separator installed in the discharge chamber 27 of the rear housing 9 (housing 11). The oil separator 48 separates the lubricating oil mixed in the refrigerant discharged from the scroll compression mechanism 4 to the discharge chamber 27 from the refrigerant. An inlet 49 is formed in the oil separator 48, and the refrigerant containing oil flowing in from the inlet 49 rotates in the oil separator 48. The oil is separated by the centrifugal force at this time, and the refrigerant flows from the outflow port at the upper end to the discharge port 30, and is discharged to the discharge pipe as described above.

[0035] An oil storage chamber 44 is formed in the rear housing 9 below the oil separator 48, and the oil separated from the refrigerant by the oil separator 48 flows into the oil storage chamber 44 from the lower end of the oil separator 48. In the figure, 43 is a back pressure passage formed from the rear housing 9 to the central housing 6. The back pressure passage 43 is a passage that connects the oil separator 48 in the discharge chamber 27 (discharge side of the scroll compression mechanism 4) in the rear housing 9 with the back pressure chamber 39, and has a throttle hole 50 in the embodiment. Thus, it is configured to supply the discharge pressure adjusted by the throttle hole 50 of the back pressure passage 43 to the back pressure chamber 39 together with the oil in the oil storage chamber 44 separated by the oil separator 48.

[0036] The pressure (back pressure) in the back pressure chamber 39 generates a back pressure load that presses the movable scroll 22 against the fixed scroll 21. The movable scroll 22 overcomes the compression reaction force from the pressure chamber 34 of the scroll compression mechanism 4 and is pressed against the fixed scroll 21 by the back pressure load, and the contact between the volutes 24, 32 and the cover plates 31, 23 is maintained, so that the refrigerant can be compressed by the pressure chamber 34.

[0037] Furthermore, in the embodiment, back pressure holes 5 are cut and provided at two locations of the cover plate 31 of the movable scroll 22 to connect the back pressure chamber 39 with the compression chamber 34. When the pressure (back pressure) in the back pressure chamber 39 is too large, each back pressure hole 5 plays a role in releasing the pressure (refrigerant and oil) from the back pressure chamber 39 to the compression chamber 34.

[0038] On the other hand, the inverter box 8 is composed of a box body 10 and a cover member 15 that closes an opening of one end surface of the box body 10. The box body 10 constitutes an inverter housing portion 13 that houses the inverter 3. After the inverter 3 is housed in the inverter housing portion 13, the cover member 15 is attached to the box body 10.

[0039] An airtight plate 52 is mounted on the end wall 7A (partition wall) of the stator housing 7, and an electrically conductive airtight pin 53 is mounted on the airtight plate 52. One end of the airtight pin 53 penetrates the end wall 7A and enters the motor chamber 12, and is connected to the coil of the stator 25 of the electric motor 2. In addition, the other end of the airtight pin 53 is electrically connected to the circuit board 51 via a press-fit terminal 56.

[0040] Next, refer to Figure 2 , Figure 3 The shape of the tip end portion of the wrap 32 of the movable scroll 22 according to the embodiment will be described in detail. Figure 2 is a plan view of the movable scroll 22 as viewed from the lap 32 side (surface side), Figure 3 It is a diagram for explaining the height of the wrapping terminal vicinity of the wrap 32 .

[0041] exist Figure 2 In FIG. 1 , O is the center of the vortex base circle of the volute 32 of the movable scroll 22, and S is the outer wall expansion start point of the volute 32. Furthermore, when a line from the center O of the vortex base circle through the outer wall expansion start point S toward the outside of the movable scroll 22 is set as L1, the point where the line L1 intersects with the outermost volute 32 is set as P1. In addition, P2 is the winding end point of the volute 32.

[0042] In the present invention, the volute 32 in the range from point P1 to the winding end point P2 is formed with an inclined portion whose height gradually decreases toward the winding end point P2. In the case of the embodiment, as the inclined portion, a first inclined portion 32A whose height gradually decreases toward the winding end point P2 and a second inclined portion 32B whose height gradually decreases toward the winding end point P2 are formed, and a flat portion 32C with a constant height is formed between the first inclined portion 32A and the second inclined portion 32B. That is, in the volute 32 of the embodiment, in the range from point P1 to the winding end point P2, the first inclined portion 32A, the flat portion 32C and the second inclined portion 32B are continuously formed from the point P1 side.

[0043] In addition, if Figure 3As shown, when the starting end of the first inclined portion 32A is set to P3, the terminal end of the first inclined portion 32A, that is, the starting end of the flat portion 32C is set to P4, the terminal end of the flat portion 32C, that is, the starting end of the second inclined portion 32B is set to P5, and the terminal end of the second inclined portion 32B is set to P6, the length of the vortex tooth 32 satisfies the relationship that the length of the first inclined portion 32A from P3 to P4 is less than the length of the flat portion 32C from P4 to P5 and is less than the length of the second inclined portion 32B from P5 to P6.

[0044] That is, the length of the lap 32 of the movable scroll 22 is set to be longer in the flat portion 32C than in the first inclined portion 32A and longer in the second inclined portion 32B than in the flat portion 32C. In the embodiment, the height of the lap 32 of the movable scroll 22 is 10 μm lower at the terminal end P4 of the first inclined portion 32A (the starting end of the flat portion 32C) than at the starting end P3 (the normal height of the lap 32), and is 50 μm lower at the terminal end P6 of the second inclined portion 32B than at the starting end P3.

[0045] In the case where no tip seal is provided at the tip of the volute 32 as shown in the embodiment, in the operating state where the scroll compressor 1 is repeatedly stopped and restarted as described above, since the movable scroll 22 is started while tipping over (tilting), the tip of the volute 32 of the movable scroll 22 contacts the cover plate 23 of the fixed scroll 21 very strongly until the start is stable. Therefore, a drag groove is formed in the cover plate 23 of the fixed scroll 21, especially near the winding terminal where the wall thickness of the volute 32 is thin and the surface pressure is easy to rise.

[0046] Therefore, when the height of the volute 32 is lowered to prevent strong contact, if the range of the height reduction is too large, the function of the scroll compressor 1 will be impaired. On the other hand, if the range is too small, the occurrence of a strong contact state between the cover plate 23 of the fixed scroll 21 and the volute 32 of the movable scroll 22 cannot be effectively suppressed, and the durability is impaired.

[0047] On the other hand, as in the present invention, in the range from the point P1 where the line L1 extending from the center O of the vortex base circle through the outer wall extension start point S toward the outside of the volute 32 of the movable scroll 22 intersects with the outermost volute 32 to the winding end point P2, an inclined portion whose height gradually decreases toward the winding end point P2 is formed, and further, in this range, by continuously forming the first inclined portion 32A whose height gradually decreases toward the winding end point P2, the flat portion 32C whose height remains unchanged, and the second inclined portion 32B whose height gradually decreases toward the winding end point P2 as in the embodiment, the drag of the cover plate 23 of the fixed scroll 21 is improved while maintaining the function as the scroll compressor 1, and fatigue damage can be effectively prevented from occurring at the top of the volute 32 of the movable scroll 22 near the winding end point. As a result, durability can be improved, and both function and durability can be achieved.

[0048] In addition, in the embodiment, the volute 32 of the movable scroll plate 22 is continuously formed with a first inclined portion 32A whose height gradually decreases toward the winding end point P2, a flat portion 32C whose height remains unchanged, and a second inclined portion 32B whose height gradually decreases toward the winding end point P2. However, it is not limited to this. In the range from the center O of the vortex base circle through the outer wall extension start point S to the point P1 where the line L1 toward the outside intersects the outermost volute tooth 32 to the winding end point P2, a series of inclined portions (with no flat portion in the middle) whose height gradually decreases toward the winding end point P2 can also be formed, or more inclined portions and flat portions than those in the embodiment can also be formed.

[0049] In addition, in the embodiment, the present invention is applied to the scroll compressor 1 used in the refrigerant circuit of the vehicle air conditioning device, but it is not limited to this, and the present invention is effective for the scroll compressor used in the refrigerant circuit of various refrigeration devices. In addition, in the embodiment, the present invention is applied to the so-called inverter-integrated scroll compressor, but it is not limited to this, and it can also be applied to a general scroll compressor that does not have an inverter integrally. Description of Reference Numerals

[0050] 1 Scroll compressor 2 Electric motor 4 Scroll compression mechanism (compression mechanism) 5 Back pressure hole 11. Housing 21 Fixed scroll 22 Movable scroll 23, 31 Cover 24, 32 scroll teeth 32A First inclined portion 32B Second inclined portion 32C Flat L1 is a line extending from the center O of the vortex basic circle through the outer wall and starting point S toward the outside of the movable scroll 22. O The center of the swirl base circle of the volute 32 of the movable scroll 22 P1 Point where line L1 intersects the outermost volute 32 P2: End point of winding of scroll 32 S is the point at which the outer wall of the spiral wrap 32 starts to expand.

Claims

1. A scroll compressor, comprising a compression mechanism composed of a fixed scroll and a movable scroll, wherein the fixed scroll and the movable scroll have spiral volutes formed on the surfaces of their respective cover plates, respectively, and the movable scroll is caused to revolve relative to the fixed scroll, and a compression chamber formed between the volutes of the two scrolls is caused to move while shrinking from the outside to the inside, thereby compressing a working fluid, characterized in that: The volute of the movable scroll has an inclined portion, and the inclined portion gradually decreases in height toward the winding end point (P2) within a range from a point (P1) where a line (L1) extending from the center of a vortex base circle through a starting point of an outer wall extending outward intersects with an outermost volute to a winding end point (P2).

2. The scroll compressor according to claim 1, characterized in that: The lap of the movable scroll is continuously formed within the range with a first inclined portion whose height gradually decreases toward the wrapping end point (P2), a flat portion whose height remains constant, and a second inclined portion whose height gradually decreases toward the wrapping end point (P2).

3. The scroll compressor according to claim 2, characterized in that: The height of the lap of the movable scroll decreases by 10 μm at the terminal end of the first inclined portion and decreases by 50 μm at the terminal end of the second inclined portion.

4. The scroll compressor according to claim 2, characterized in that: The length of the wrap of the movable scroll is set to be longer in the flat portion than in the first inclined portion, and longer in the second inclined portion than in the flat portion.

5. The scroll compressor according to claim 1, characterized in that: The two scroll disks are subjected to coating treatment.

6. The scroll compressor according to claim 1, characterized in that: A back pressure chamber is formed on the back side of the cover plate of the movable scroll, and a back pressure hole is formed through the cover plate of the movable scroll so as to communicate the back pressure chamber with the compression chamber.

7. The scroll compressor according to any one of claims 1 to 6, characterized in that: No tip seal is provided at the lap tips of the fixed scroll and the movable scroll.

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