Helical compressor

Abstract

[Problem] To provide a helical compressor capable of having an improved compression efficiency without being affected by deformation of a casing due to internal pressure. [Solution] A helical compressor 1 comprises: a casing 2; a roller 4 disposed inside the casing 2; a cylindrical sleeve 3 provided between the casing 2 and the roller 4; a spiral groove 38 formed in the outer circumferential surface of the roller 4; and a spiral blade 7. The blade 7 abuts the sleeve 3 and demarks a compression chamber 37 formed between the sleeve 3 and the roller 4. As a result of the volume of the compression chamber 37 being reduced while the blade 7 advances in a thrust direction of the casing 2 through revolution of the roller 4, a refrigerant suctioned into the compression chamber 37 is compressed.

Description

Helical Compressor

[0001] The present invention relates to a helical compressor that includes a cylindrical casing, a roller revolving inside the casing, and a spiral blade, and compresses a working fluid.

[0002] A helical compressor, which is a helical blade type fluid machine, includes a cylindrical casing, a roller disposed inside the casing, and a blade that defines a compression chamber between the casing and the roller. The structure is such that the roller revolves relative to the casing, thereby reducing the volume of the compression chamber while advancing in the thrust direction of the casing, so as to compress the working fluid sucked into the compression chamber. In such cases, a spiral groove is formed on the outer surface of the roller, and the blade is fitted into the groove in a retractable and protrusible manner (see, for example, Patent Document 1 and Patent Document 2).

[0003] Furthermore, in this type of helical compressor, an attachment portion called a mounting boss for attaching the compressor to a mounted component (e.g., a vehicle) is provided on the outer surface of the casing, so the thickness dimension of the casing is not uniform.

[0004] Japanese Unexamined Patent Publication No. 11-159485, Japanese Unexamined Patent Publication No. 2003-97464

[0005] Here, in a helical compressor, the blade abuts against the inner peripheral surface of the casing to define the compression chamber. If the blade separates from the inner peripheral surface of the casing, the compression chamber cannot be properly formed, resulting in a decrease in compression efficiency. Therefore, in a helical compressor, it is necessary to maintain the cylindricity of the inner surface of the casing that contacts the blade at 15 µm or less.

[0006] However, as described above, the thickness dimension of the casing is not uniform. For example, the thickness dimension is larger at the attachment portion, resulting in higher strength, while the thickness dimension is smaller at other portions, resulting in lower strength.

[0007] Therefore, when internal pressure is applied to the cylindrical casing, distortion occurs in the casing due to the difference in strength between the aforementioned attachment portion and other portions, resulting in the cylindricity of the inner surface becoming 30 µm or more, which causes the problem that the roundness cannot meet the required quality.

[0008] The present invention was made to solve the aforementioned conventional technical problems, and aims to provide a helical compressor that can improve compression efficiency without being affected by deformation of the casing due to internal pressure.

[0009] The helical compressor of the present invention comprises a casing, a roller disposed inside the casing and revolving relative to the casing, a cylindrical sleeve provided between the casing and the roller, a helical groove formed on the outer circumferential surface of the roller, and a helical blade fitted into the helical groove so as to be retractable into the groove. The blade abuts against the sleeve and partitions a compression chamber formed between the sleeve and the roller, and the volume of the compression chamber decreases as it advances in the thrust direction of the casing due to the roller's revolving motion, thereby compressing the working fluid drawn into the compression chamber.

[0010] The helical compressor of the second invention is characterized in that the sleeve is press-fitted into the inside of the casing in the above invention.

[0011] The helical compressor of the third invention is characterized in that the sleeve is movably provided inside the casing in the present invention.

[0012] The helical compressor of the fourth invention is characterized in that, in the present invention, the working fluid flows between the casing and the sleeve.

[0013] The fifth helical compressor of the present invention is characterized in that it comprises a mounting portion for attaching the casing to the mounting portion, wherein the mounting portion is integrally formed and protrudes from the outer surface of the casing corresponding to the region where the blades are located.

[0014] The sixth helical compressor is characterized in that, in each of the above inventions, the casing is made of aluminum and the sleeve is made of an iron-based material.

[0015] The helical compressor of the present invention has a cylindrical sleeve between the casing and the rollers, and the compression chamber formed between this sleeve and the rollers is partitioned by spiral blades. As the volume of the compression chamber decreases while advancing in the thrust direction of the casing due to the revolution of the rollers, the working fluid drawn into the compression chamber is compressed. Therefore, even when internal pressure is applied to the casing when compressing the working fluid, the compression efficiency can be improved without being affected by the distortion deformation of the casing.

[0016] In particular, as in the fifth invention, when the mounting portion is integrally formed protruding from the outer surface of the casing corresponding to the region where the blade exists, the difference in strength between the mounting portion and the rest of the casing can cause distortion in the casing due to internal pressure, which tends to reduce compression efficiency. However, the presence of the sleeve allows for an improvement in compression efficiency without being affected by the deformation of the casing.

[0017] Furthermore, if the casing is made of aluminum as in the sixth invention, constructing the sleeve from an iron-based material effectively satisfies the required quality of the sleeve's roundness, thereby further improving the single-phase compression efficiency.

[0018] In this case, if the sleeve is press-fitted into the inside of the casing as in the second invention, it becomes unnecessary to use fasteners such as bolts, and the structure can be simplified.

[0019] On the other hand, if the sleeve is provided to be movable inside the casing, as in the third invention, it becomes possible to improve the ease of assembly.

[0020] Furthermore, by allowing the working fluid to flow between the casing and the sleeve, as in the fourth invention, it becomes possible to eliminate or suppress the generation of distortion due to the pressure difference between the inside and outside of the sleeve.

[0021] This is a perspective view of a helical compressor according to one embodiment to which the present invention is applied. This is a longitudinal cross-sectional side view of the helical compressor shown in Figure 1, excluding the motor casing.

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Figure 1 is a perspective view of a helical compressor 1 according to one embodiment of the present invention, and Figure 2 is a longitudinal cross-sectional side view of the portion of the helical compressor 1 other than the motor casing 5.

[0023] (1) Helical Compressor 1 The helical compressor 1 of this embodiment consists of a cylindrical aluminum casing 2, a cylindrical sleeve 3 made of an iron-based material (iron in this embodiment), a cylindrical roller 4, a shaft 6, a helical and flexible blade 7, a motor casing 5, etc. The helical compressor 1 of this embodiment is used, for example, in the refrigerant circuit of a vehicle air conditioning system to inhale, compress and discharge a refrigerant (including oil) as a working fluid.

[0024] (2) Casing 2 The casing 2 of the embodiment consists of a bottomed cylindrical casing body 11 with an opening at only one end in the thrust direction (axial direction of the cylinder), and a casing side plate 12 attached by bolts to close the opening at one end of the casing body 11, and the inner circumferential surface of the casing body 11 has a perfectly circular inner circumferential surface shape. That is, the casing body 11 integrally has a cylindrical portion 10 with an opening at one end in the thrust direction and an end wall 13 located at the other end of the cylindrical portion 10 in the thrust direction.

[0025] A bearing portion 14, consisting of a ball bearing, is embedded in the center of the inner surface of the casing side plate 12, and a bearing portion 16, also consisting of a ball bearing, is embedded in the center of the inner surface of the end wall 13 located at the other end of the casing body 11 in the thrust direction. The ends of the shaft 6 are then rotatably supported by these bearing portions 14 and 16.

[0026] The aforementioned motor casing 5 is connected to the casing side plate 12. One end of the shaft 6 protrudes from the casing side plate 12 into the motor casing 5, and this protruding end of the shaft 6 (the left end in Figure 2) is connected to a motor (not shown) inside the motor casing 5, which rotates the shaft 6.

[0027] In Figure 2, 19 is a sealing material that slidably seals the space between the shaft 6 and the casing side plate 12. This sealing material 19 ensures that the sleeve 3, roller 4, shaft 6, and blade 7 are securely housed within the casing 2.

[0028] Furthermore, an intake port 21 is formed in the casing side plate 12, and a discharge port 22 is formed in the cylindrical portion 10 on the end wall 13 side of the casing body 11. In addition, an annular thrust plate 26 is attached to the inside of the casing side plate 12, and an annular thrust plate 27 is also attached to the inside of the end wall 13. The ends of the roller 4 are configured to slidably contact each of the thrust plates 26 and 27.

[0029] (3) Sleeve 3 The sleeve 3 in the embodiment is an iron tube with a cylindrical shape that is open at both ends, and has dimensions that allow it to be positioned almost snugly inside the casing body 11 of the casing 2. In the embodiment, it is press-fitted along the inside of the casing body 11 and fixed to the casing 2.

[0030] The inner circumferential surface of this sleeve 3 also has a perfectly circular shape, but in this embodiment, an introduction section 18 for introducing refrigerant (working fluid) between the casing body 11 and the sleeve 3 is formed on the outer surface of the sleeve 3 (or the inner surface of the casing 2).

[0031] (4) Roller 4 The roller 4 has an overall cylindrical shape with both ends open, and cam bearing portions 28 and 29, each consisting of ball bearings, are attached to the inside of both ends. In addition, a plurality of circular recesses 31 are formed on one end face of the roller 4, and a pin 32 for preventing rotation, attached to the casing side plate 12, enters and engages with each recess 31. The pin 32 is slidably engaged with the circular inner surface of the recess 31, and these recesses 31 and pins 32 constitute the rotation prevention mechanism of the roller 4.

[0032] The roller 4 revolves around the casing body 11 and sleeve 3 of the casing 2 without rotating on its own due to the rotation of the shaft 6, thanks to the anti-rotation mechanism consisting of the recess 31 and pin 32, and the action of the cams 33 and 34 of the shaft 6, which will be described later. At that time, the outer surface of the roller 4 slides against the inner surface of the sleeve 3 (line contact). The 36 is an annular sealing material that seals the space between the thrust plate 27 and the end wall 13 of the casing body 11.

[0033] The outer diameter of the roller 4 is set to be smaller than the inner diameter of the casing body 11 of the casing 2 and the sleeve 3, thereby forming a refrigerant (working fluid) compression chamber 37 between the sleeve 3 and the roller 4.

[0034] One end of the compression chamber 37 (the side facing the casing side plate 12) is connected to the intake port 21, and the other end (the side facing the end wall 13 of the casing body 11) is connected to the discharge port 22.

[0035] On the outer circumferential surface of the roller 4, spiral grooves 38 are continuously formed as recesses from one end in the thrust direction (the side of the suction port 21 of the casing body 11 that constitutes the casing 2) to the other end (the side of the discharge port 22 of the end wall 13 of the casing body 11), and the pitch of the spiral grooves 38 is set to gradually decrease from one end to the other.

[0036] (5) Blade 7 The blade 7 is designed to be deformable and is made of a flexible material such as PTFE. The blade 7 is fitted into the spiral groove 38 of the roller 4 so as to be able to protrude and retract, and slidably contacts the inner surface of the spiral groove 38, as well as the inner circumferential surface of the sleeve 3, thereby partitioning the compression chamber 37 between the sleeve 3 and the roller 4 in the thrust direction.

[0037] As described above, the pitch of the spiral groove 38 is set to gradually decrease from one end (the suction port 21 side of the casing side plate 12) to the other end (the discharge port 22 side of the end wall 13 of the casing body 11). Therefore, the volume of the compression chamber 37 between the sleeve 3 and the roller 4, which is partitioned by the blade 7, also gradually decreases from one end to the other.

[0038] (6) Shaft 6 The shaft 6 passes through the roller 4, and both ends are rotatably supported by the bearing portions 14 and 16 of the casing side plate 12 and end wall 13, respectively, as described above. The cams 33 and 34 described above are formed eccentrically in the same direction on the shaft 6 at positions corresponding to the cam bearing portions 28 and 29 of the roller 4, and each cam 33 and 34 slidably contacts the inner surface of each cam bearing portion 28 and 29 of the roller 4.

[0039] As a result, the roller 4 does not rotate on its own axis as the shaft 6 rotates, but instead revolves eccentrically around the casing body 11 and sleeve 3. Note that 43 is a balancer formed on the shaft 6, eccentrically in the opposite direction to each of the cams 33 and 34.

[0040] (7) Operation of the helical compressor 1 Next, the operation of the helical compressor 1 with the above configuration will be explained. It should be assumed that a predetermined amount of lubricating oil is pre-filled inside the helical compressor 1. When the shaft 6 rotates due to the motor described above, the cams 33 and 34 also rotate, and due to the action of the cams 33 and 34 and the aforementioned anti-rotation mechanism (recess 31 and pin 32), the roller 4 revolves around the casing body 11 and sleeve 3 without rotating on its own axis.

[0041] Refrigerant (working fluid) is drawn in from the external refrigerant circuit through the intake port 21 and flows into the compression chamber 37 at one end (the casing side plate 12 side). The refrigerant drawn into the compression chamber 37 is pushed by the roller 4, which revolves while contacting the inner circumferential surface of the sleeve 3, and moves towards the other end (the end wall 13 side). As mentioned above, the volume of the compression chamber 37 partitioned by the blade 7 gradually decreases from one end to the other, so the refrigerant drawn into the compression chamber 37 at one end between the sleeve 3 and the roller 4 is gradually compressed. The refrigerant (including oil) thus compressed is then discharged to the external refrigerant circuit through the discharge port 22 located at the other end.

[0042] (8) Mounting portions 41, 42 Here, as shown in Fig. 1, a pair of mounting portions 41 and 42 are integrally formed on the outer surface of the casing main body 11 of the casing 2. These mounting portions 41 and 42 are boss portions for mounting the helical compressor 1 to a mounted portion formed on a vehicle (a portion where the helical compressor 1 is mounted to a vehicle not shown), and each has a through hole formed for bolt fastening.

[0043] Each of the mounting portions 41 and 42 is formed integrally so as to protrude from the outer surface of the casing main body 11 at a position corresponding to the region where the blade 7 exists, and in the case of the embodiment, they are formed at opposing positions on the same circumference of the casing 2.

[0044] (9) Effect of sleeve 3 Here, when the mounting portions 41 and 42 are integrally formed on the outer surface of the casing main body 11 of the casing 2 corresponding to the region where the blade 7 exists as in the embodiment, the thickness dimension at the mounting portions 41 and 42 of the aluminum-made casing main body 11 is larger than the thickness dimension of the casing main body 11 at other portions on the same circumference.

[0045] That is, the strength of the casing main body 11 at the mounting portions 41 and 42 is higher than the strength of other portions on the same circumference. Therefore, when the sleeve 3 is not provided, the refrigerant is compressed in the compression chamber between the casing main body 11 partitioned by the blades 7 and the roller 4, and the internal pressure of the casing 2 increases, so that the portion of the casing main body 11 with low strength, that is, the portion other than the mounting portions 41 and 42 bulges outward, causing distortion in the casing main body 11.

[0046] When the casing main body 11 is distorted, the cylindricity of the inner surface of the casing main body 11 becomes, for example, 30 μm or more, so that the roundness cannot satisfy the required quality, the compression chamber cannot be properly formed, and the compression efficiency decreases.

[0047] On the other hand, in the present invention, since the sleeve 3 is provided inside the casing main body 11 of the casing 2, even when internal pressure is applied to the casing 2 during compression of the refrigerant, the compression efficiency can be improved without being affected by the distortion deformation of the casing main body 11.

[0048] In particular, when the casing 2 is made of aluminum as in the embodiment, forming the sleeve 3 from an iron-based material can effectively satisfy the required quality for the roundness of the sleeve 3, thereby further improving the compression efficiency.

[0049] Further, in the embodiment, the sleeve 3 is press-fitted inside the casing main body 11 of the casing 2, which eliminates the need for using fixing members such as bolts and enables simplification of the structure.

[0050] Furthermore, in the embodiment, an introduction portion 18 for allowing a refrigerant to flow in is formed between the casing 2 and the sleeve 3, which makes it possible to eliminate or suppress the occurrence of distortion caused by the pressure difference between the inside and outside of the sleeve 3.

[0051] In addition, in the above-described embodiment, the sleeve 3 is press-fitted inside the casing main body 11 of the casing 2; however, the present invention is not limited thereto, and the sleeve 3 may be provided movably inside the casing main body 11, and in this case, improvement in assembly workability can be achieved.

[0052] Furthermore, in the embodiment, the present invention is applied to a helical compressor 1 used in a refrigerant circuit of a vehicle air conditioner; however, the working fluid is not limited to the refrigerant of the embodiment, and may be air or other gases. The present invention is also effective for helical compressors used for various purposes in terms of application.

[0053] 1 Helical compressor 2 Casing 3 Sleeve 4 Roller 6 Shaft 7 Blade 11 Casing main body 12 Casing side plate 13 End wall 14, 16 Bearing portion 18 Introduction portion 21 Suction port 22 Discharge port 28, 29 Cam bearing portion 31 Recess 32 Pin 33, 34 Cam 37 Compression chamber 38 Spiral groove 41, 42 Mounting portion

Claims

1. A helical compressor comprising a casing, a roller disposed inside the casing and revolving relative to the casing, a cylindrical sleeve provided between the casing and the roller, a helical groove formed on the outer circumferential surface of the roller, and a helical blade fitted into the helical groove so as to be retractable into the helical groove, wherein the blade abuts against the sleeve and partitions a compression chamber formed between the sleeve and the roller, and the volume of the compression chamber decreases as it advances in the thrust direction of the casing due to the revolving roller, thereby compressing the working fluid drawn into the compression chamber.

2. The helical compressor according to claim 1, characterized in that the sleeve is press-fitted into the inside of the casing.

3. The helical compressor according to claim 1, characterized in that the sleeve is movably provided inside the casing.

4. The helical compressor according to claim 1, characterized in that the working fluid flows between the casing and the sleeve.

5. The helical compressor according to claim 1, further comprising a mounting portion for attaching the casing to a mounting portion, wherein the mounting portion is integrally formed and protrudes from the outer surface of the casing corresponding to the region where the blade is located.

6. The helical compressor according to any one of claims 1 to 5, characterized in that the casing is made of aluminum and the sleeve is made of an iron-based material.

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