The present invention relates to a scroll fluid machine and a method for manufacturing the same.
A scroll fluid machine in which a fixed scroll member including a spiral-shaped wall provided on an end plate and an orbiting scroll member including a spiral-shaped wall provided on an end plate are engaged with each other and rotated in orbital motion to compress or expand fluid is generally known.
A so-called stepped scroll compressor such as that disclosed in Patent Document 1 is known as the above-mentioned scroll fluid machine. In this stepped scroll compressor, a step is provided at a position along the spiral direction in the tooth crest surfaces and the tooth base surfaces of the spiral-shaped walls of the fixed scroll and the orbiting scroll such that the height of the wall is greater on the outer peripheral side of the step than on the inner peripheral side of the step. The stepped scroll compressor performs compression (three-dimensional compression) not only in the circumferential direction of the wall, but also in the height direction, and therefore can achieve a larger displacement and a larger compressor capacity in comparison with a common scroll compressor (two-dimensional compression) that does not include the step.
Patent Document 1: JP 2015-55173 A
In the stepped scroll compressor, however, fluid leakage at the step is disadvantageously large. In addition, stress is concentrated at the root portion of the step, and the strength is disadvantageously reduced.
In view of this, the inventor et al. have considered regarding a configuration provided with a continuous inclined portion in place of the step provided in the wall and the end plate. In addition, a tip seal is provided in the tooth crest of the wall for the purpose of sealing the gap between the tooth crest and the opposing tooth base.
However, since the inclined portion is formed in the wall, the way of installing the tip seal to achieve desired performance has not yet been considered.
In view of the foregoing, an object of the present invention is to provide a scroll fluid machine and a method for manufacturing the same which can achieve desired performance of a tip seal installed in a tooth crest of a wall including an inclined portion.
A scroll compressor and a method for manufacturing the same according to an embodiment of the present invention employ the following means to solve the problems described above.
A scroll fluid machine according to an aspect of the present invention includes: 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. 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 from an outer peripheral side toward an inner peripheral side of the first wall and the second wall is provided, a tip seal is provided in groove portions formed in tooth crests of the first wall and the second wall corresponding to the inclined portion, the tip seal being configured to make contact with a tooth base facing the tip seal to perform sealing against fluid, and in a stop state where the scroll members do not perform compression of fluid, an inclination height of the tip seal is smaller than an inclination height of the wall.
Since an inclined portion in which the distance between opposing surfaces of the first end plate and the second end plate facing each other gradually decreases from the outer peripheral side toward the inner peripheral side of the wall is provided, the fluid sucked from the outer peripheral side is compressed not only by reduction of a compression chamber corresponding to the spiral shape of the wall, but also by reduction of the distance between the opposing surfaces of the end plates as the fluid moves toward the inner peripheral side.
The inclination height of the tip seal is set to a value smaller than that of the inclination height of the wall in a stop state where compression of fluid is not performed by the scroll members. With this configuration, the tip seal is installed such that, in the stop state, the tip seal protrudes from the tooth crest to the opposing tooth base side more on the inner periphery side than on the outer peripheral side. Since the tip seal protrudes from the tooth crest to the tooth base side more on the inner periphery side than on the outer peripheral side, fluid enters, more easily on the inner peripheral side than on the outer peripheral side, the groove portion in which the tip seal is inserted. When an operation is started from the stop state and the compression of the fluid is performed by the scrolls, the compressed fluid enters the groove portion of the inner periphery side of the tip seal, and biases the tip seal toward the tooth base from the back surface of the tip seal. Accordingly, the pressing forth of the tip seal against the tooth base is larger on the inner periphery side where the fluid pressure is high during operation, and thus a high sealing performance can be achieved, improving the performance of the scroll fluid machine.
It is to be noted that the “inclination height” means the difference between the height of the outermost peripheral end and the height of the innermost peripheral end of the inclined portion.
Further, in the scroll fluid machine according to an aspect of the present invention, the height of the tip seal in the height direction of the wall is greater than the difference between the inclination height of the wall and the inclination height of the tip seal.
Since the height of the tip seal in the height direction of the wall is greater than the difference between the inclination height of the wall and the inclination height of the tip seal, the tip seal is prevented from dropping off from the groove portion.
Further, in the scroll fluid machine according to an aspect of the present invention, the tip seal is made of an elastically deformable material.
When the tip seal is made of an elastically deformable material (such as resin), the tip seal can be installed in the groove portion by utilizing elastic deformation such that the inclination height of the tip seal is smaller than the inclination height of the wall in a stop state. As a result, it is unnecessary to form the tip seal in a shape inclined in the height direction, and therefore, by manufacturing a flat tip seal that has no inclination, the ease of manufacture and inspection of the tip seal increases.
A manufacturing method according to an aspect of the present invention is a method of manufacturing a scroll fluid machine including: 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 from an outer peripheral side toward an inner peripheral side of the first wall and the second wall is provided, and a tip seal is provided in groove portions formed in tooth crests of the first wall and the second wall corresponding to the inclined portion, the tip seal being configured to make contact with a tooth base facing the tip seal to perform sealing against fluid, the method including: installing the tip seal in the groove portions such that an inclination height of the tip seal is smaller than an inclination height of the wall; and installing the first scroll member and the second scroll member by engaging the first scroll member with the second scroll member after installing the tip seal.
Since the scroll members are engaged with each other and installed after the tip seal is installed such that the inclination height of the tip seal is smaller than the inclination height of the wall, it is possible to readily set the state where the tip seal protrudes to the tooth base side more on the inner periphery side than on the outer peripheral side in the stop state before the compression of the fluid is performed.
With the configuration in which the inclination height of the tip seal is set to a value smaller than that of the inclination height of the wall in the stop state where the compression of the fluid is not performed by the scroll members, the pressing forth of the tip seal against the tooth base is high on the inner periphery side where the fluid pressure is high during operation, and thus a high sealing performance can be achieved, improving the performance of the scroll fluid machine.
Embodiments of the present invention will be described below with reference to the drawings.
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.
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
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.
As illustrated in
As illustrated in
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.
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.
As illustrated in
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.
As illustrated with hatching in
φ=tan−1(h/D1) (1)
In this manner, the inclination φ of the inclined portion is constant with respect to the circumferential direction in which the walls 3b and 5b having the spiral shape extend.
As illustrated in
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,
It is to be noted that the tip seal is provided also in the tooth crest of the wall 5b of the orbiting scroll 5.
The inclination height Ls′ of the tip seal 7 is set to a value smaller than that of the inclination height Ls of the wall 3b. Here, the inclination height Ls′ of the tip seal 7 is a difference between the height of a position in the tip seal 7 which corresponds to the wall inclined connecting portion 3b5 (see
To install the tip seal 7 as illustrated in
The height Hc of the tip seal is greater than the difference between the inclination height Ls of the wall 3b and the inclination height Ls′ of the tip seal 7. That is, the height Hc of the tip seal 7 is set to satisfy the following equation.
Ls−Ls′≤Hc (2)
In addition, the inclination height Ls′ of the tip seal 7 is set also in the tooth crest of the wall 5b of the orbiting scroll 5 as in
The above-described scroll compressor 1 operates in the following manner.
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.
According to the present embodiment, the following effects are achieved.
The inclination height Ls′ of the tip seal 7 in a stop state where compression of fluid by the scrolls 3 and 5 is not performed is set to a value smaller than that of the inclination height of the walls 3b and 5b. With this configuration, the tip seal 7 is installed such that the tip seal 7 protrudes from the tooth crest to the tooth base side more on the inner periphery side than on the outer peripheral side in the stop state (see
Since the height Hc of the tip seal is greater than the difference between the inclination height Ls′ of the tip seal 7 and the inclination height Ls of the walls 3b and 5b (see the expression (2)), the tip seal 7 can be prevented from dropping off from the tip seal groove 3d.
When the tip seal 7 is made of a material such as an elastically deformable resin, the tip seal 7 can be installed by utilizing elastic deformation. That is, the tip seal 7 can be installed in the tip seal groove 3d so as to be elastically deformed such that the inclination height Ls′ of the tip seal 7 is smaller than the inclination height Ls of the walls 3b and 5b in the stop state. As a result, it is unnecessary to form the tip seal 7 in a shape inclined in the height direction, and therefore, by manufacturing flat tip seal 7 that has no inclination when no external force is applied thereto, the ease of manufacture and inspection of the tip seal 7 increases.
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.
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
In addition, as illustrated in
While the wall flat portions 3b23b3, 5b2 and 5b3 and the end plate flat portions 3a23a3, 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.
While a scroll compressor is described in the above-mentioned embodiment, the present invention is applicable to a scroll expander used as an expander.
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JP2016-161210 | Aug 2016 | JP | national |
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PCT/JP2017/029243 | 8/14/2017 | WO | 00 |
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WO2018/034256 | 2/22/2018 | WO | A |
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