The present invention relates to a tip seal and a scroll fluid machine using the same.
In general, a scroll fluid machine is known, in which a fixed scroll member and an orbiting scroll member each having a spiral wall provided on an end plate mesh with each other so as to perform a revolution orbiting movement and a fluid is compressed or expanded.
As the scroll fluid machine, a so-called stepped scroll compressor which is described in PTL 1 is known. In the stepped scroll compressor, step portions are provided at positions of tooth tip surfaces and tooth bottom surfaces of spiral walls of a fixed scroll and an orbiting scroll in a spiral direction and a height on an outer peripheral side of each wall is higher than a height on an inner peripheral side thereof with each step portion as a boundary. In the stepped scroll compressor, compression (three-dimensional compression) is performed not only in a circumferential direction of the wall but also in a height direction thereof, and thus, compared to a general scroll compressor (two-dimensional compression) which does not have the step portion, an amount of displacement increases, and thus, compressor capacity can increase.
[PTL 1] Japanese Unexamined Patent Application Publication No. 2015-55173
However, in a stepped scroll compressor, there is a problem that fluid leakage in a step portion is large. In addition, there is a problem that stress concentrates on a base portion of the step portion and strength decreases.
Meanwhile, the inventors are studying to provide a continuously inclined portion instead of the step portion provided on a wall and an end plate.
A groove portion for accommodating a tip seal is formed on a tooth tip, which is a tip of the wall, along a spiral direction of the wall. During an operation of a scroll compressor, the tip seal comes into contact with a tooth bottom facing the tooth tip while sliding on the tooth bottom, and thus, a fluid leakage is suppressed.
In a case where a flat portion of the wall having a constant height is provided to be adjacent to the inclined portion of the wall, the tip seal is accommodated in the groove portion formed on the inclined portion of the wall and the flat portion of the wall. In this case, even when the wall performs an orbiting movement, a distance between the flat portion of the tip seal and the facing end plate (tooth bottom) is constant. Meanwhile, the inclined portion of the tip seal repeats movements toward and away from the facing end plate (tooth bottom) according to the orbiting movement of the wall. Accordingly, repeated stress is generated in an adjacent region between the flat portion of the tip seal and the inclined portion of the tip seal, and thus, there is a possibility of a damage. In addition, the inclined portion of the tip seal repeats movements toward and away from the facing end plate (tooth bottom), and thus, there is a problem that the inclined portion wears more than the flat portion.
The present invention is made in consideration of the above-described circumstances, and an object thereof is to provide a tip seal and a scroll fluid machine using the same capable of improving durability of the tip seal installed in the tooth tip of the wall even in a case where a continuously inclined portion is provided in the wall.
In order to achieve the above-described object, a tip seal and a scroll fluid machine using the same of the present invention adopt the following means.
According to an aspect of the present invention, there is provided a tip seal which is installed in a groove portion formed on a tooth tip of a spiral wall of a scroll fluid machine and is formed of a resin, the seal including: an inclined portion which is installed in the groove portion of the wall whose height is continuously changed in a spiral direction and a flat portion which is installed in the groove portion of the wall whose height is constant in the spiral direction and is adjacent to the inclined portion, in which a concave portion is formed at a position avoiding an adjacent region between the inclined portion and the flat portion.
Even when the spiral wall performs an orbiting movement, a distance between the flat portion of the tip seal and the facing wall portion (tooth bottom) is constant. Meanwhile, the inclined portion of the tip seal repeats movements toward and away from the facing wall portion (tooth bottom) according to the orbiting movement of the spiral wall. Accordingly, repeated stress is generated in the adjacent region between the flat portion and the inclined portion of the tip seal, and thus, there is a possibility of a damage. In addition, in a case where the tip seal is manufactured, when the tip seal is resin-molded and released from a mold, the tip seal is pressed by an extrusion pin and is taken out of the mold. In this case, the concave portion is formed on the surface of the tip seal. If this concave portion is formed in the adjacent region between the flat portion and the inclined portion of the tip seal, stress concentration is generated, and thus, the tip seal is easily damaged. Accordingly, the concave portion is formed at the position avoiding the adjacent region between the inclined portion and the flat portion, and thus, the repeated stress in the adjacent region is reduced, and a risk of damages in the adjacent region can be reduced. The surface of the tip seal on which the concave portion is formed includes a surface of the facing wall portion (tooth bottom) side and a back surface or a side surface thereof.
Moreover, in the tip seal according to the aspect of the present invention, the concave portion is provided at a position away from a connection position between the flat portion and the inclined portion by twice or more width of the flat portion.
If the concave portion is provided at the position away from the connection position between the flat portion and the inclined portion by twice or more width of the flat portion, the repeated stress generated at the connection position does not significantly affect the concave portion, which is preferable. Moreover, the width of the flat portion means a dimension in a direction orthogonal to a longitudinal direction of the tip seal, and is typically the same as a width of the inclined portion.
In addition, in the tip seal according to the aspect of the present invention, the inclined portion is thicker than the flat portion.
The inclined portion repeats movements toward and away from the facing wall portion (tooth bottom), and thus, the inclined portion wears more than the flat portion. Accordingly, the inclined portion is made thicker than the flat portion to improve wear resistance. Moreover, the thickness of each of the inclined portion and the flat portion means a dimension in a standing direction of the wall.
Moreover, in the tip seal according to the aspect of the present invention, the inclined portion is formed of a material having wear resistance higher than that of the flat portion.
The inclined portion repeats movements toward and away from the facing wall portion (tooth bottom), and thus, the inclined portion wears more than the flat portion. Accordingly, the inclined portion is formed of a material having wear resistance higher than that of the flat portion. The material having high wear resistance includes PolyEtherEtherKetone (PEEK) or polytetrafluoroethylene (PTFE) or a material obtained by applying Diamond-LikeCarbon (DLC) coating or PTFE coating to a base material. In general, Polyphenylenesulfide (PPS) or the like is used as a material of the flat portion.
In addition, in the tip seal according to the aspect of the present invention, the tip seal is divided into the inclined portion and the flat portion at a connection position therebetween.
The tip seal is divided into the inclined portion and the flat portion at the connection position therebetween, and thus, it is possible to avoid occurrence of the repeated stress due to bending at the connection position.
In addition, according to another aspect of the present invention, there is provided a scroll fluid machine including: a first scroll member having a first end plate on which a spiral first wall is provided; a second scroll member having a second end plate on which a spiral second wall is provided, the second end plate being disposed to face the first end plate and the second wall meshing with the first wall such that the second scroll member performs a revolution orbiting movement relative to the first scroll member; and an inclined portion in which an inter-facing surface distance between the first end plate and the second end plate facing each other continuously decreases from outer peripheral sides of the first wall and the second wall toward inner peripheral sides thereof, in which the above-described tip seal which comes into contact with a facing tooth bottom to perform sealing for a fluid is provided in a groove portion formed on each tooth tip of the first wall and the second wall corresponding to the inclined portion.
A concave portion is formed at a position avoiding an adjacent region between an inclined portion of a tip seal and a flat portion of the tip seal, and thus, repeated stress in the adjacent region is reduced, and a risk of damages in the adjacent region can be reduced. The inclined portion of the tip seal is made thicker than the flat portion, and thus, it is possible to improve wear resistance of the inclined portion of the tip seal.
Hereinafter, an embodiment according to the present invention will be described with reference to the drawings.
In
Each of the fixed scroll 3 and the orbiting scroll 5 is a metal compression mechanism which is formed of an aluminum alloy or steel, and is accommodated in a housing (not shown). The fixed scroll 3 and the orbiting scroll 5 suck a fluid, which is introduced into the housing, from an outer peripheral side, and discharge the compressed fluid from a discharge port 3c positioned at a center of the fixed scroll 3 to the outside.
The fixed scroll 3 is fixed to the housing, and as shown in
The fixed scroll 3 and the orbiting scroll 5 are assembled to each other such that centers thereof are separated from each other by an orbiting radius ρ, the walls 3b and 5b mesh with each other with phases deviated from each other by 180°, and a slight clearance (tip clearance) in a height direction is provided in the room temperature between tooth tips and tooth bottoms of the walls 3b and 5b of both scrolls. Accordingly, a plurality pairs of compression chambers which are formed to be surrounded by the end plates 3a and 5a and the walls 3b and 5b are symmetrically formed about a scroll center between both scrolls 3 and 5. The orbiting scroll 5 performs a revolution orbiting movement around the fixed scroll 3 by a rotation prevention mechanism such as an Oldham ring (not shown).
As shown in
As shown in
In addition, the meaning of the continuity in the inclined portion in the present embodiment is not limited to a smoothly connected inclination but also includes an inclined portion in which small step portions inevitably generated during processing are connected to each other in a stepwise fashion and the inclined portion is continuously inclined as a whole. However, the inclined portion does not include a large step portion such as a so-called stepped scroll.
Coating is applied to the wall inclined portions 3b1 and 5b1 and/or the end plate inclined portions 3a1 and 5al. For example, the coating includes manganese phosphate processing, nickel phosphorus plating, or the like.
As shown in
Similarly, in the tooth bottom of the end plate 5a of the orbiting scroll 5, end plate flat portions 5a2 and 5a3 each having a constant height are provided. Each of the end plate flat portions 5a2 and 5a3 is provided over a region of 180° around the center of the orbiting scroll 5. End plate inclined connection portions 5a4 and 5a5 which become curved portions are respectively provided at positions at which the end plate flat portions 5a2 and 5a3 and the end plate inclined portion 5a1 are connected to each other.
As shown by hatching in
φ=tan−1(h/D1) (1)
In this way, the inclination φ of the inclined portion is constant in a circumferential direction in which each of the spiral walls 3b and 5b extends.
As shown in
If both the scrolls 3 and 5 perform the revolution orbiting movement relative to each other, the positions of the tooth tip and the tooth bottom are relatively deviated by an orbiting diameter (orbiting radius ρ×2). In the inclined portion, the tip clearance between the tooth tip and the tooth bottom is changed due to the positional deviation between the tooth tip and the tooth bottom. For example, in
The tip seal inclined portion 7A and the tip seal flat portion 7B are integrally formed and are fixed to each other at a connection position C1. Moreover, in the connection position C1, the surface 7a and the back surface 7b may be chamfered so as to be smoothly connected to each other.
A plurality of concave portions 8 are formed on the surface 7a of the tip seal 7 at predetermined intervals along a longitudinal direction of the tip seal 7. When the tip seal 7 is resin-molded and released from a mold, each concave portion 8 is formed as a trace of a head shape of an extrusion pin on the surface 7a of the tip seal 7 when the tip seal 7 is pressed by the extrusion pin and taken out of the mold.
As described with reference to
The above-described scroll compressor 1 is operated as follows. The orbiting scroll 5 performs the revolution orbiting movement around the fixed scroll 3 by a drive source such as an electric motor (not shown). Accordingly, the fluid is sucked from the outer peripheral sides of the respective scrolls 3 and 5, and the fluid is taken into the compression chambers surrounded by the respective walls 3b and 5b and the respective end plates 3a and 5a. The fluid in the compression chambers is sequentially compressed while being moved from the outer peripheral side toward the inner peripheral side, and finally, the compressed fluid is discharged from a discharge port 3c formed in the fixed scroll 3. When the fluid is compressed, the fluid is compressed in the height directions of the walls 3b and 5b in the inclined portions formed by the end plate inclined portions 3a1 and 5a1 and the wall inclined portions 3b1 and 5b1, and thus, the fluid is three-dimensionally compressed.
According to the present embodiment, the following operational effects are exerted. The concave portion 8 is formed at the position avoiding the adjacent region between the tip seal inclined portion 7A and the tip seal flat portion 7B, and thus, the repeated stress in the adjacent region is reduced, and a risk of damages in the adjacent region can be reduced.
Moreover, the configuration in which the concave portions 8 are formed on the surface 7a of the tip seal 7 is described. However, the concave portion 8 may be provided on the back surface 7b or the side surface 7c of the tip seal 7.
In addition, as shown in
Moreover, the tip seal inclined portion 7A may use a material having the wear resistance higher than that of the tip seal flat portion 7B. For example, PolyEtherEtherKetone (PEEK) or polytetrafluoroethylene (PTFE) may be applied to the tip seal inclined portion 7A, or Diamond-LikeCarbon (DLC) coating or PTFE coating may be applied to a base material such as Polyphenylene sulfide (PPS). In this case, PPS or the like is used as a material of the tip seal flat portion 7B.
In addition, the tip seal 7 may be divided into the tip seal inclined portion 7A and the tip seal flat portion 7B at the connection position C1 therebetween. Accordingly, it is possible to avoid occurrence of the repeated stress due to the bending at the connection position C1.
Moreover, in the present embodiment, although the end plate inclined portions 3a1 and 5a1 and the wall inclined portions 3b1 and 5b1 are provided on both the scrolls 3 and 5. However, they may be provided in any one of the scrolls 3 and 5. Specifically, as shown in
In the present embodiment, the wall flat portions 3b2, 3b3, 5b2, and 5b3 and the end plate flat portions 3a2, 3a3, 5a2, and 5a3 are provided. However, the flat portions on the inner peripheral side and/or the outer peripheral side may be omitted, and the inclined portion may be provided so as to extend to the entire walls 3b and 5b.
In the present embodiment, the scroll compressor is described. However, the present invention can be applied to a scroll expander which is used as an expander.
Number | Date | Country | Kind |
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2017-158113 | Aug 2017 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2018/023649 | 6/21/2018 | WO | 00 |