Scroll fluid machine including first and second scroll members
11002274 · 2021-05-11
Assignee
Inventors
Cpc classification
F04C18/0276
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F04C27/005
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F04C18/023
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
Abstract
Provided is a scroll fluid machine which can appropriately set a tip clearance between a tooth base and a tooth crest having an inclined portion and can achieve desired performance. An inclined portion in which a distance between opposing surfaces of an end plate of a fixed scroll and an end plate of an orbiting scroll facing each other gradually decreases from an outer peripheral side toward an inner peripheral side is provided. A tip clearance between a tooth crest of a wall of the orbiting scroll and a tooth base of the end plate of the fixed scroll facing the tooth crest at normal temperature is greater on the inner peripheral side than on the outer peripheral side.
Claims
1. A scroll fluid machine comprising: a first scroll member including a first end plate and a first wall provided on the first end plate, the first wall having a spiral shape; and a second scroll member including a second end plate that is disposed to face the first end plate, and a second wall provided on the second end plate, the second scroll member being configured to relatively rotate in orbital motion with the second wall engaged with the first wall, the second wall having a spiral shape, wherein an inclined portion in which a distance between opposing surfaces of the first end plate and the second end plate facing each other gradually decreases, along a spiral direction, from an outer peripheral side toward an inner peripheral side of the first wall and the second wall is provided, the inclined portion includes a wall inclined portion provided on both of the first wall and the second wall, and an end plate inclined portion provided on both of the first end plate and the second end plate, the scroll fluid machine further comprises: a wall flat portion that is connected to the wall inclined portion and whose height does not vary, the wall flat portion being provided in an outermost peripheral portion and an innermost peripheral portion of both of the first wall and the second wall; and an end plate flat portion that is connected to the end plate inclined portion and is provided on both of the first end plate and the second end plate, the end plate flat portion corresponding to the wall flat portion, in the inclined portion, a tip clearance between a tooth crest of the walls and a tooth base of the end plates facing the tooth crest is greater on the inner peripheral side than on the outer peripheral side in the spiral direction at normal temperature, a flat portion tip clearance between the wall flat portion of the first wall and the end plate flat portion of the second end plate is constant in the spiral direction of the first wall, and a flat portion tip clearance between the wall flat portion of the second wall and the end plate flat portion of the first end plate is constant in the spiral direction of the second wall.
2. The scroll fluid machine according to claim 1, wherein a tip seal is provided in groove portions formed in the tooth crests of the first wall and the second wall, the tip seal being configured to make contact with a tooth base facing the tip seal to perform sealing against fluid, and a groove depth of the groove portions is greater on the inner peripheral side than on the outer peripheral side in the spiral direction.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
DESCRIPTION OF EMBODIMENTS
First Embodiment
(12) The first embodiment of the present invention will be described below with reference to the drawings.
(13)
(14) The fixed scroll 3 and the orbiting scroll 5 are compression mechanisms made of metal such as aluminum alloy and iron, and are housed in a housing not illustrated. The fixed scroll 3 and the orbiting scroll 5 suck, from the outer peripheral side, fluid guided into the housing, and discharge compressed fluid from a discharge port 3c located at the center of the fixed scroll 3.
(15) The fixed scroll 3 is fixed to the housing, and includes a substantially disk-plate-shaped end plate (first end plate) 3a, and a spiral-shaped wall (first wall) 3b disposed upright on one side surface of the end plate 3a as illustrated in
(16) The fixed scroll 3 and the orbiting scroll 5 are engaged with each other such that the centers thereof are separated from each other by an orbit radius p and that the phases of the walls 3b and 5b are shifted by 180°, and fixed scroll 3 and the orbiting scroll 5 are mounted such that a slight clearance (tip clearance) in the height direction is provided between the tooth crest and the tooth base of the walls 3b and 5b of the scrolls at normal temperature. With this configuration, multiple pairs of compression chambers that are defined by the surrounding end plates 3a and 5a and the walls 3b and 5b and are symmetric about the scroll center are formed between the scrolls 3 and 5. With a rotation prevention mechanism such as an Oldham ring not illustrated, the orbiting scroll 5 rotates in orbital motion around the fixed scroll 3.
(17) As illustrated in
(18) As illustrated in
(19) It is to be noted that the term “gradually” in the inclined portion in the present embodiment is not limited to a smooth inclination, and may include a form that is visually recognized as being gradually inclined as viewed in the entire inclined portion in which small steps inevitably resulting from working processes are connected together stepwise. It should be noted that large steps such as a so-called stepped scroll is not included.
(20) A coating is provided on the wall inclined portions 3b1 and 5b1 and/or the end plate inclined portions 3a1 and 5a1. Examples of the coating include manganese phosphate treatment, nickel phosphor plating, and the like.
(21) As illustrated in
(22) Likewise, the tooth base of the end plate 5a of the orbiting scroll 5 is provided with end plate flat portions 5a2 and 5a3, each of which has a constant height. Likewise, the end plate flat portions 5a2 and 5a3 are provided in a region of 180° around the center of the orbiting scroll 5. End plate inclined connecting portions 5a4 and 5a5, which serve as bent portions, are provided at portions connecting between the end plate inclined portion 5a1 and the end plate flat portions 5a2 and 5a3, respectively.
(23) As illustrated with hatching in
(24)
φ=tan.sup.−1(h/D1) (1)
(25)
(26) As illustrated in
(27) When the scrolls 3 and 5 perform relative rotation in orbital motion, the positions of the tooth crest and the tooth base are relatively shifted by an orbit diameter (the orbit radius ρ×2). In the inclined portion, the tip clearance between the tooth crest and the tooth base varies in response to the positional displacement of the tooth crest and the tooth base. For example,
(28) In the present embodiment, as illustrated in
(29)
(30)
(31) In
(32) It is to be noted that a line S1 indicates a line of a case where the end plate flat portion 3a3 on the outer peripheral side has a constant height.
(33) The tooth crest position b1 of the orbiting scroll 5 indicates the wall inclined connecting portion 5b5 on the outer peripheral side, and the position b10 indicates the wall inclined connecting portion 5b4 on the inner peripheral side. Accordingly, the portion on the outer peripheral side (left side) of position b1 is the end plate flat portion 5b3 of on the outer peripheral side, the portion on the inner peripheral side (right side) of the position b10 is the end plate flat portion 5b2, and the portion between the position b1 and the position b10 is the wall inclined portion 5b1.
(34) The inclination φ1 of the wall inclined portion 5b1 in the region from the position b1 to the position b5 is identical to the inclination φ1 of the end plate inclined portion 3a1, and the inclination φ2 of the wall inclined portion 5b1 in the region from the position b5 to the position b10 is greater than the inclination φ1.
(35) It is to be noted that a line S2 indicates a line of a case where the wall flat portion 5b3 on the outer peripheral side has a constant height. S3 is a line extended by extrapolation from the position b5 toward the inner peripheral side (right side), that is, a line at the inclination φ1.
(36) While the position b5 where the inclination is changed may be appropriately set, the position b5 is set in consideration of the thermal expansion difference between the inner peripheral side and the outer peripheral side during the operation.
(37) By changing the inclination of the wall inclined portion 5b1 at the position b5 to increase the inclination of the inner peripheral side of the position b5 in the above-mentioned manner, the tip clearance T (see
(38) On the other hand, the tip clearance T of the flat portion between the end plate flat portions 3a2 and 3a3 and the wall flat portions 5b2 and 5b3 is constant in the spiral direction. It should be noted that, since the inclination of the inclined portion is greater on the inner peripheral side as described above, the tip clearance T of the flat portions 3a3 and 5b3 on the outer peripheral side is set to a value greater than the tip clearance T of the flat portions 3a2 and 5b2 on the inner peripheral side.
(39)
(40) As illustrated in the drawing, the tip clearances T in the flat portions 3a3 and 5b3 on the outer peripheral side and the flat portions 3a2 and 5b2 on the inner peripheral side are constant regardless of the orbit angle θ, and the tip clearance T of the flat portions 3a2 and 5b2 on the inner peripheral side is larger than that of the flat portions 3a3 and 5b3 on the outer peripheral side.
(41) On the other hand, the tip clearance T of the inclined portion on the outer peripheral side at a position slightly on the inclined portion side relative to the positions a1 and b1, and the tip clearance amount of the inclined portion on the inner peripheral side at a position slightly on the inclined portion side relative to positions a10 and b10 vary in a sine curve in accordance with the orbit angle θ. The reason for this is that the inclined portion moves forward or backward in accordance with the orbit angle θ in the inclined portion as described above with reference to
(42) The relationship of the tip clearance T between the tooth base of the end plate 3a of the fixed scroll 3 and the tooth crest of the wall 5b of the orbiting scroll 5 applies also to the relationship between the tooth base of the end plate 5a of the orbiting scroll 5 and the tooth crest of the wall 3b of the fixed scroll 3.
(43) As with the above-described tip clearance T, a groove depth 3d1 (see
(44) It is to be noted that a similar groove depth is set to a tip seal groove provided in the tooth crest of the wall 5b of the orbiting scroll 5.
(45) The above-described scroll compressor 1 operates in the following manner.
(46) The orbiting scroll 5 is rotated in orbital motion around the fixed scroll 3 by a driving source such as an electric motor not illustrated. In this manner, fluid is sucked from the outer peripheral side of the scrolls 3 and 5, and the fluid is taken into the compression chamber surrounded by the walls 3b and 5b and the end plates 3a and 5a. The fluid in compression chamber is compressed as it moves from the outer peripheral side toward the inner peripheral side, and finally compressed fluid is discharged from the discharge port 3c formed in the fixed scroll 3. When the fluid is compressed, the fluid is compressed also in the height direction of the walls 3b and 5b in the inclined portion defined by the end plate inclined portions 3a1 and 5a1 and the wall inclined portions 3b1 and 5b1, and thus three-dimensional compression is performed.
(47) According to the present embodiment, the following effects are achieved.
(48) On the inner peripheral side of the scrolls 3 and 5, fluid is compressed and temperature rise resulting from the compression heat is large in comparison with the outer peripheral side of the scrolls 3 and 5. In addition, since heat is less dissipated on the inner peripheral side than on the outer peripheral side, the temperature is high on the inner peripheral side. Accordingly, during operation, thermal expansion is greater on the inner peripheral side than on the outer peripheral side, and the tip clearance T between the tooth crest and the tooth base is small. In view of this, the tip clearance T on the inner peripheral side at normal temperature is set to a value greater than that of the outer peripheral side. With this configuration, even when heat expansion occurs during operation of the scroll compressor 1, a desired tip clearance T can be set from the inner peripheral side to the inner peripheral side, and fluid leakage can be reduced as much as possible while avoiding interference between the tooth crest and the tooth base.
(49) Also in the tip seal 7, temperature rise is greater on the inner peripheral side than on outer peripheral side. Accordingly, the tip seal rear gap 3d2 between the bottom surface of the tip seal 7 and the bottom surface of the tip seal groove 3d becomes smaller on the inner peripheral side than on outer peripheral side with thermal expansion of the tip seal 7. In particular, in the case where the tip seal 7 made of resin whose linear thermal expansion coefficient is larger than the scrolls 3 and 5 made of metal is used, reduction of the tip seal rear gap 3d2 is significant.
(50) When the tip seal rear gap 3d2 is closed and the bottom surface of the tip seal 7 and the bottom surface of the groove portion make contact with each other, the tip seal 7 protrudes to the opposing tooth base side more than necessary, and the performance of the scroll compressor 1 might be reduced. In view of this, to secure the tip seal rear gap 3d2 required according to the thermal expansion, the groove depth 3d1 of the tip seal groove 3d is set such that the groove depth 3d1 is greater on the inner peripheral side than on the outer peripheral side. With this configuration, it is possible to avoid a situation in which the inner peripheral side of the tip seal 7 makes contact with the bottom surface of the tip seal groove 3d at an excessive pressure due to thermal expansion, and it is thus possible to suppress reduction of the performance of the scroll compressor 1.
(51) When the tooth crests of the walls 3b and 5b and/or the tooth bases of the end plates 3a and 5a are inclined, it is difficult to set the measurement point and it is therefore difficult to achieve high measurement accuracy. In view of this, to perform shape measurement with high accuracy, the flat portions 3a2 3a3, 5b2 and 5b3 are provided at the outermost peripheral portions and the innermost peripheral portions of the walls 3b and 5b and the end plates 3a and 5a, and the tip clearance T in the flat portion is set to a constant value. With this configuration, the dimension of the scroll shape and the tip clearance can be readily controlled.
(52) While the inclination of the tooth crest of the wall 5b of the orbiting scroll 5 is varied to adjust the tip clearance T in the above-mentioned embodiment as described with reference to
(53) In addition, while the inclination of the tooth crest of the wall 5b of the orbiting scroll 5 is varied in two-stage in the above-mentioned embodiment, the inclination of may be varied in three-stage or greater. Alternatively, the tip clearance may be set such that the tip clearance on the inner peripheral side is greater than that of the outer peripheral side by setting different inclinations between the inclination of the inclined portion of the tooth crest and the inclination of the inclined portion of the tooth base facing the tooth crest without providing the variation in the inclined portion.
(54) In addition, while the end plate inclined portions 3a1 and 5a1 and the wall inclined portions 3b1 and 5b1 are provided in the scrolls 3 and 5 in the above-mentioned embodiment, the end plate inclined portion and the wall inclined portion may be provided in only one of the scrolls 3 and 5.
(55) To be more specific, in the case where the wall inclined portion 5b1 is provided in the wall of one scroll (the orbiting scroll 5, for example) and the end plate inclined portion 3a1 is provided in the end of plate 3a of the other scroll as illustrated in
(56) In addition, as illustrated in
(57) While the wall flat portions 3b2 3b3, 5b2 and 5b3 and the end plate flat portions 3a2 3a3, 5a2 and 5a3 are provided in the above-mentioned embodiment, the flat portion of the inner peripheral side and/or the outer peripheral side may be omitted so as to extend the inclined portion in the entirety of the walls 3b and 5b.
(58) While a scroll compressor is described in the above-mentioned embodiment, the present invention is applicable to a scroll expander used as an expander.
REFERENCE SIGNS LIST
(59) 1 Scroll Compressor (Scroll Fluid Machine) 3 Fixed Scroll (First Scroll Member) 3a End Plate (First End Plate) 3a1 End Plate Inclined Portion 3a2 End Plate Flat Portion (Inner Peripheral Side) 3a3 End Plate Flat Portion (Outer Peripheral Side) 3a4 End Plate Inclined Connecting Portion (Inner Peripheral Side) 3a5 End Plate Inclined Connecting Portion (Outer Peripheral Side) 3b Wall (First Wall) 3b1 Wall Inclined Portion 3b2 Wall Flat Portion (Inner Peripheral Side) 3b3 Wall Flat Portion (Outer Peripheral Side) 3b4 Wall Inclined Connecting Portion (Inner Peripheral Side) 3b5 Wall Inclined Connecting Portion (Outer Peripheral Side) 3c Discharge port 3d Tip Seal Groove 3d1 Groove Depth 3d2 Tip Seal Rear Gap 5 Orbiting Scroll (Second Scroll Member) 5a End Plate (Second End Plate) 5a1 End Plate Inclined Portion 5a2 End Plate Flat Portion (Inner Peripheral Side) 5a3 End Plate Flat Portion (Outer Peripheral Side) 5b Wall (Second Wall) 5b1 Wall Inclined Portion 5b2 Wall Flat Portion (Inner Peripheral Side) 5b3 Wall Flat Portion (Outer Peripheral Side) 5b4 Wall Inclined Connecting Portion (Inner Peripheral Side) 5b5 Wall Inclined Connecting Portion (Outer Peripheral Side) 7 Tip Seal Hc Height of Tip Seal L Distance between Opposing Surfaces T Tip Clearance φ, φ1, φ2 Inclination