JP7654474B2 - Scroll Fluid Machine - Google Patents

Description

This disclosure relates to scroll fluid machinery.

A scroll fluid machine is generally known in which a fixed scroll member having a spiral wall on an end plate is meshed with an orbiting scroll member, and the scroll members are caused to revolve in an orbital motion to compress or expand a fluid.

A so-called stepped scroll compressor, as shown in Patent Document 1, is known as such a scroll fluid machine. In this stepped scroll compressor, steps are provided at positions along the spiral direction of the tooth tip surface and tooth bottom surface of the spiral wall of the fixed scroll and the orbiting scroll, and the height of the outer periphery of the wall at each step is higher than the height of the inner periphery. Since the stepped scroll compressor compresses not only the wall circumferentially but also in the height direction (three-dimensional compression), it is possible to increase the displacement and compressor capacity compared to a general scroll compressor (two-dimensional compression) that does not have steps.

However, stepped scroll compressors can suffer from fluid leakage at the steps, reducing efficiency.

In response to this, it has been proposed to provide a continuous inclined portion instead of the stepped portions on the wall body and end plate, as shown in Patent Document 2.

In Patent Document 2, in consideration of the problem that it is difficult to set the measurement point and improve the measurement accuracy when the tooth tip of the wall is inclined, flat portions are provided on the outermost and/or innermost peripheries of the wall and end plate to perform shape measurement with high accuracy. It is disclosed that the flat portions of the wall and end plate are provided over an area of 180° or more around the center of the scroll member. However, if the range of the flat portions greatly exceeds 180°, the area of the inclined portions decreases and the inclination of the inclined portions increases, which may increase the risk of fluid leakage. For this reason, it is described that it is preferable that the flat portions of the wall and end plate are in an area of 180° (paragraph [0018] of Patent Document 2).

JP 2015-055173 A JP 2018-028300 A

However, after careful study by the inventors, it was found that the compression chamber formed at the innermost circumference of the scroll member has the highest pressure, resulting in a large pressure difference and a large amount of fluid leakage from the tip gap, which is the gap between the tooth tip (wall) and the tooth bottom (end plate). Even if a flat wall portion and a flat end plate portion are provided at the innermost circumference, if an inclined portion exists in the region that forms the compression chamber at the innermost circumference, the tip gap at the inclined portion changes depending on the orbital angle, so the tip gap becomes larger and fluid leakage increases further.

This disclosure was made in consideration of these circumstances, and aims to provide a scroll fluid machine that can reduce fluid leakage from the tip gap as much as possible, even in a scroll fluid machine that has an inclined portion.

In order to solve the above-mentioned problems, the scroll fluid machine of the present disclosure includes a first scroll member having a first end plate on which a spiral-shaped first wall body is provided, a second scroll member having a second end plate arranged to face the first end plate and having a spiral-shaped second wall body provided on the second end plate, the second wall body meshing with the first wall body to perform a relative orbital motion, and a sloped portion in which the distance between the opposing surfaces of the first end plate and the second end plate facing each other continuously decreases from the outer circumferential side of the first wall body and the second wall body toward the inner circumferential side, a wall flat portion provided on the innermost circumferential part of at least one of the first wall body and the second wall body and having an unchanged height, an end plate flat portion provided on the innermost circumferential part of at least one of the first end plate and the second end plate and corresponding to the wall flat portion, a wall sloped portion in which the height of the wall body forming the sloped portion continuously increases so as to form the sloped portion from the wall flat portion toward the outer circumferential side, and a wall sloped portion in which the height of the wall body forming the sloped portion continuously increases from the end plate flat portion toward the outer circumferential side. the wall flat portion and the end plate flat portion are provided over a range from an innermost peripheral position on the high pressure port side to an outer peripheral position, and in an area that is 360° or more (excluding 360°) around the center of the scroll member in which the wall flat portion and the end plate flat portion are provided, and the outer peripheral position is provided in a range from 90° on the inner peripheral side to 90° on the outer peripheral side in the spiral direction of the first wall body and the second wall body , when an outer peripheral position that defines the range of a first compression chamber formed at the innermost peripheral position at the timing of communication with the high pressure port is taken as a reference outer peripheral position.

Fluid leakage from chip gaps can be reduced as much as possible.

1 is a vertical cross-sectional view of a fixed scroll and an orbiting scroll of a scroll compressor according to an embodiment of the present disclosure. FIG. FIG. 2 is a perspective view showing the orbiting scroll of FIG. 1 . FIG. 2 is a plan view showing the fixed scroll of FIG. 1 . 4 is a plan view showing a state in which an orbiting scroll is superimposed on a fixed scroll. FIG. FIG. 2 is a schematic diagram showing a wall body stretched in the spiral direction. FIG. 5 is a partially enlarged view showing an area Z in FIG. 4 . FIG. 7 is a side view showing the tip seal gap of the inclined portion shown in FIG. 6, illustrating a state in which the tip seal gap is relatively small. FIG. 7 is a side view showing the tip seal gap of the inclined portion shown in FIG. 6, illustrating a state in which the tip seal gap is relatively large. 7B is a vertical cross-sectional view of the tip seal and its surroundings, in which a state corresponding to FIG. 7A is shown by solid lines and a state corresponding to FIG. 7B is shown by dashed lines. FIG. 4 is a vertical cross-sectional view showing the tip seal and its surroundings in a flat portion. 4 is a graph showing in-cylinder pressure versus turning angle. FIG. 11 is a vertical sectional view showing a modified example, in which a scroll having no step portion is combined with the modified example. FIG. 11 is a vertical sectional view showing a modified example in combination with a stepped scroll. 1 is a plan view showing the range of a flat portion provided on the innermost circumference, illustrating the state in which the orbiting scroll is superimposed on the fixed scroll. FIG. 11B is a plan view showing a modification of FIG. 11A. FIG. 11B is a plan view showing a modification of FIG. 11A.

Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.
1 shows a fixed scroll (first scroll member) 3 and an orbiting scroll (second scroll member) 5 of a scroll compressor (scroll fluid machinery) 1. The scroll compressor 1 is used as a compressor that compresses a gas refrigerant (fluid) that performs a refrigeration cycle of, for example, an air conditioner or the like.

The fixed scroll 3 and the orbiting scroll 5 are a compression mechanism made of metal such as aluminum alloy or iron, and are housed in a housing (not shown). The fixed scroll 3 and the orbiting scroll 5 suck in the fluid guided into the housing from the outer periphery, and discharge the compressed fluid from the discharge port (high pressure port) 3c in the center of the fixed scroll 3 to the outside.

The fixed scroll 3 is fixed to the housing and has a substantially circular end plate (first end plate) 3a and a spiral wall body (first wall body) 3b erected on one side of the end plate 3a. The orbiting scroll 5 has a substantially circular end plate (second end plate) 5a and a spiral wall body (second wall body) 5b erected on one side of the end plate 5a. The spiral shape of each wall body 3b, 5b is defined using, for example, an involute curve or an Archimedes curve.

The fixed scroll 3 and the orbiting scroll 5 are engaged with their centers separated by the orbit radius ρ, and the phase of the walls 3b, 5b is shifted by 180°, and they are assembled so that there is a slight vertical clearance (tip clearance) between the tooth tips and tooth bottoms of the walls 3b, 5b of both scrolls at room temperature. As a result, multiple pairs of compression chambers are formed between the scrolls 3, 5, surrounded by the end plates 3a, 5a and the walls 3b, 5b, symmetrically with respect to the scroll center. The orbiting scroll 5 revolves around the fixed scroll 3 by an anti-rotation mechanism such as an Oldham ring (not shown).

The distance L between the opposing surfaces of the two opposing end plates 3a, 5a is provided with a slope that continuously decreases from the outer periphery to the inner periphery of the spiral wall bodies 3b, 5b.

As shown in FIG. 2, the wall 5b of the orbiting scroll 5 has a wall inclined portion 5b1 whose height increases continuously from the inner periphery side to the outer periphery side. The tooth tip of the wall inclined portion 5b1 faces the tooth bottom surface of the fixed scroll 3, and an end plate inclined portion 3a1 (see FIG. 1) is provided that inclines according to the inclination of the wall inclined portion 5b1. The wall inclined portion 5b1 and the end plate inclined portion 3a1 form a continuous inclined portion. Similarly, as shown in FIG. 1, the wall 3b of the fixed scroll 3 also has a wall inclined portion 3b1 whose height continuously inclines from the inner periphery side to the outer periphery side, and the end plate inclined portion 5a1 facing the tooth tip of the wall inclined portion 3b1 is provided on the end plate 5a of the orbiting scroll 5.

In this embodiment, the meaning of "continuous" in the inclined portion is not limited to a smoothly connected inclination, but also includes small steps that are unavoidably generated during processing and are connected in a staircase shape, and the inclined portion as a whole is continuously inclined. However, it does not include large steps such as those found in so-called stepped scrolls.

As shown in FIG. 2, the wall 5b of the orbiting scroll 5 is provided on its innermost and outermost sides with an inner wall flat portion 5b2 and an outer wall flat portion 5b3, respectively, which have a constant height.
The inner circumferential side wall flat portion 5b2 is provided over a range from the innermost position to the outer circumferential position on the side of the center O2 (see FIG. 1) of the orbiting scroll 5. More specifically, the inner circumferential side wall flat portion 5b2 is provided over a range that defines the first compression chamber 12 (see FIG. 4) that is formed at the innermost circumference when communicating with the discharge port 3c. The reference outer circumferential position (wall inclined connection portion 5b4) that defines the outer circumferential position of the first compression chamber 12 is provided on the reference outer circumferential line L1 as shown in FIG. 11A. The reference outer circumferential line L1 indicates the angular position of the wall 5b in the spiral direction and coincides with the outer circumferential position of the first compression chamber 12.

As shown in Fig. 2, the outer peripheral side wall flat portion 5b3 is provided over an area of 180° from the outermost end 5b6 of the orbiting scroll 5 toward the inner peripheral side. However, it may be more than 180° or less than 180°. Also, the outer peripheral side wall flat portion 5b3 may be omitted and the wall inclined portion 5b1 may be formed up to the outermost end.
At positions where the wall flat portions 5b2, 5b3 and the wall inclined portion 5b1 are connected, wall inclined connection portions 5b4, 5b5 that serve as bent portions are provided. The wall inclined connection portion 5b4 on the inner peripheral side is provided on the reference outer periphery line L1 as shown in FIG. 11A.

2, the tooth bottom of the end plate 5a of the orbiting scroll 5 is also provided with an inner end plate flat portion 5a2 and an outer end plate flat portion 5a3 with a constant height. The inner end plate flat portion 5a2 is provided over a range from the innermost position to the outer periphery position on the center O2 (see FIG. 1) side of the orbiting scroll 5. More specifically, the inner end plate flat portion 5a2 is provided over a range that defines the first compression chamber 12 (see FIG. 4) that is formed at the innermost circumference when communicating with the discharge port 3c. The reference outer periphery position (end plate inclined connection portion 5a4) that defines the outer periphery position of the first compression chamber 12 is provided on the reference outer periphery line L2 as shown in FIG. 11A. The reference outer periphery line L2 indicates the angular position in the spiral direction and coincides with the outer periphery position of the first compression chamber 12.

As shown in FIG. 2, the outer peripheral end plate flat portion 5a3 is provided over an area of 180° around the center of the orbiting scroll 5.
At the positions where the end plate flat portions 5a2, 5a3 and the end plate inclined portion 5a1 are connected, end plate inclined connection portions 5a4, 5a5 are provided as bent portions. The end plate inclined connection portion 5a4 on the inner circumference side is provided on the reference outer periphery line L2 as shown in Fig. 11A. Note that the end plate inclined connection portion 5a4 has a semicircular shape when viewed in a plan view as shown in Fig. 11A, and both ends of the semicircle are provided so as to coincide with the reference outer periphery line L2.

As shown in FIG. 3, the fixed scroll 3 is provided with an inner circumferential wall flat portion 3b2 and an outer circumferential wall flat portion 3b3, similar to the orbiting scroll 5. The inner circumferential wall flat portion 3b2 is provided over a range from the innermost position to the outer circumferential position on the center O1 (see FIG. 1) side of the fixed scroll 3. More specifically, the inner circumferential wall flat portion 3b2 is provided over a range that defines the first compression chamber 12 (see FIG. 4) that is formed at the innermost circumference when communicating with the discharge port 3c. A wall inclined connection portion 3b4 that is a bent portion is provided at a position where the inner circumferential wall flat portion 3b2 and the wall inclined portion 3b1 are connected. The wall inclined connection portion 3b4 that is the outer circumferential position of the inner circumferential wall flat portion 3b2 is provided on a reference outer circumferential line L2 that passes through a reference outer circumferential position that defines the outer circumferential position of the first compression chamber 12, as shown in FIG. 11A.

As shown in FIG. 3, the tooth bottom of the end plate 3a of the fixed scroll 3 is also provided with an inner circumferential side end plate flat portion 3a2 and an outer circumferential side end plate flat portion 3a3 having a constant height. The inner circumferential side end plate flat portion 3a2 is provided over a range from the innermost peripheral position to the outer circumferential position on the center O1 (see FIG. 1) side of the fixed scroll 3. More specifically, the inner circumferential side end plate flat portion 3a2 is provided over a range that defines the first compression chamber 12 (see FIG. 4) that is formed at the innermost circumference at the timing of communicating with the discharge port 3c. At the position where the inner circumferential side end plate flat portion 3a2 and the end plate inclined portion 3a1 are connected, an end plate inclined connection portion 3a4 that serves as a bent portion is provided. The end plate inclined connection portion 3a4 that is the outer peripheral position of the inner circumferential side end plate flat portion 3a2 is provided on a reference outer peripheral line L1 that passes through a reference outer peripheral position that defines the outer peripheral position of the first compression chamber 12, as shown in FIG. 11A. In addition, the end plate inclined connection portion 3a4 is semicircular when viewed from above as shown in FIG. 11A, and both ends of this semicircle are aligned with the reference outer perimeter line L1.

As shown in FIG. 3, two injection ports 10 are provided on the end plate 3a of the fixed scroll 3. The injection ports 10 are through holes that penetrate the end plate 3a in the thickness direction, and the refrigerant that has passed through a condenser (not shown) is guided through them. The injection ports 10 are provided in positions directly opposite each other. The injection ports 10 are formed in positions that open into the second compression chamber located on the outer periphery of the first compression chamber that is formed when the injection port 10 communicates with the discharge port 3c.

Figure 4 shows the fixed scroll 3 shown in Figure 3 overlapped with the rotating scroll 5 shown in Figure 2 and meshed with it. As can be seen from the figure, the first compression chamber 12 formed at the timing of communication with the discharge port 3c, more specifically, immediately before communication with the discharge port 3c, is defined by the inner end plate flat portion 3a2 and the inner wall flat portion 3b2 of the fixed scroll 3 and the inner end plate flat portion 5a2 and the inner wall flat portion 5b2 of the rotating scroll 5. In other words, the first compression chamber 12 is defined in a sealed state only by the flat portions 3a2, 3b2, 5a2, and 5b2, and no inclined portion is formed within the first compression chamber 12. This can be understood from the fact that the end plate inclined connection portion 3a4 connecting the inner peripheral side end plate flat portion 3a2 and the end plate inclined portion 3a1, and the end plate inclined connection portion 5a4 connecting the inner peripheral side end plate flat portion 5a2 and the end plate inclined portion 5a1 are not provided in the first compression chamber 12. Note that two first compression chambers 12 (one pair) are provided symmetrically facing each other across the centers O1 and O2 of the scrolls 3 and 5.

Figure 4 shows that the injection port 10 opens into the second compression chamber 14 located on the outer periphery side of the first compression chamber 12. Two second compression chambers 14 (a pair) are provided symmetrically facing each other across the centers O1 and O2 of the scrolls 3 and 5.

FIG. 5 shows the walls 3b, 5b stretched in the spiral direction. As shown in the figure, the inner wall flat portion 3b2, 5b2 is provided over a distance D2, and the outer wall flat portion 3b3, 5b3 is provided over a distance D3. The distance D2 is a length corresponding to an area of 360° or more around the center O1, O2 of each scroll 3, 5. The distance D3 is a length corresponding to an area of 180° around the center O1, O2 of each scroll 3, 5. The wall inclined portion 3b1, 5b1 is provided over a distance D1 between the inner wall flat portion 3b2, 5b2 and the outer wall flat portion 3b3, 5b3. If the height difference between the inner wall flat portion 3b2, 5b2 and the outer wall flat portion 3b3, 5b3 is h, the inclination φ of the wall inclined portion 3b1, 5b1 is expressed by the following formula.
φ=tan ^-1 (h/D1) ... (1)
In this way, the inclination φ of the inclined portion is constant with respect to the circumferential direction in which the spiral wall bodies 3b, 5b extend. The distance D1 is longer than the distance D2 and is also longer than the distance D3.
For example, in this embodiment, the specifications of the scrolls 3 and 5 are as follows:
(1) Turning radius ρ [mm]: 2 to 15, preferably 3 to 10 (2) Number of turns of the walls 3b and 5b:
(3) Height difference h [mm]: 2 to 20, preferably 5 to 15 (4) h/Lout (height of the wall on the outermost side):
0.05 or more and 0.35 or less, preferably 0.1 or more and 0.25 or less (5) Angle range of the inclined portion (angle range corresponding to the distance D1) [°]:
(6) Inclination of the inclined portion φ [°]: 0.2 or more and 4 or less, preferably 0.5 or more and 2.5 or less

Figure 6 shows an enlarged view of the area indicated by the symbol Z in Figure 4. As shown in Figure 6, a tip seal 7 is provided on the tooth tip of the wall body 3b of the fixed scroll 3. The tip seal 7 is made of resin and contacts the tooth bottom of the end plate 5a of the opposing orbiting scroll 5 to seal the fluid. The tip seal 7 is accommodated in a tip seal groove 3d formed in the circumferential direction on the tooth tip of the wall body 3b. Compressed fluid enters this tip seal groove 3d and presses the tip seal 7 from the back side, pushing it toward the tooth bottom side and contacting the opposing tooth bottom. A similar tip seal is also provided on the tooth tip of the wall body 5b of the orbiting scroll 5.

As shown in FIGS. 7A and 7B, the height Hc of the tip seal 7 in the height direction of the wall body 3b is constant in the circumferential direction.
When the scrolls 3 and 5 revolve relatively, the positions of the tooth tips and the tooth bottoms are shifted by the orbital diameter (orbital radius ρ×2). Due to the positional shift between the tooth tips and the tooth bottoms, the tip clearance between the tooth tips and the tooth bottoms changes in the inclined portion. The tip clearance change amount Δh [mm] is, for example, 0.05 to 1.0, preferably 0.1 to 0.6. For example, in FIG. 7A, the tip clearance T is small, for example, as shown by the solid line in FIG. 8A. On the other hand, when the orbit progresses to the state of FIG. 7B, the tip clearance T becomes large, for example, as shown by the dashed line in FIG. 8B. Even if the tip clearance T changes due to the orbital motion, the tip seal 7 is pressed against the tooth bottom side of the end plate 5a from the back side by the compressed fluid, as shown by the thick arrow in FIG. 8A, so that it can follow and seal.

On the other hand, since the first compression chamber 12 (see FIG. 4) does not have an inclined portion, the tip clearance does not change according to the orbit angle as in FIG. 8A. Specifically, as shown in FIG. 8B, the orbiting scroll 5 orbits while maintaining a constant tip clearance. This makes it possible to minimize fluid leakage from the tip gap in the first compression chamber 12 compared to the other compression chambers.

The above-described scroll compressor 1 operates as follows.
A driving source such as an electric motor (not shown) causes the orbiting scroll 5 to revolve around the fixed scroll 3. As a result, fluid is sucked from the outer periphery of each scroll 3, 5, and taken into a compression chamber surrounded by each wall body 3b, 5b and each end plate 3a, 5a. The fluid in the compression chamber is compressed sequentially as it moves from the outer periphery to the inner periphery, and finally the compressed fluid is discharged from a discharge port 3c formed in the fixed scroll 3. When the fluid is compressed, it is also compressed in the height direction of the wall bodies 3b, 5b at the inclined portions formed by the end plate inclined portions 3a1, 5a1 and the wall body inclined portions 3b1, 5b1, performing three-dimensional compression.

According to this embodiment, the following advantageous effects are obtained.
After providing the chip seal 7, flat portions 3a2, 3b2, 5a2, 5b2 are provided on the innermost portions of the walls 3b, 5b and the end plates 3a, 5a, and the inner wall flat portions 3b2, 5b2 and the inner end plate flat portions 3a2, 5a2 are provided over the range of the first compression chamber 12 formed on the innermost portion at the timing when they are connected to the discharge port 3c.
Unlike the inclined portion, the tip clearance T does not change depending on the turning angle between the inner peripheral wall flat portion 3b2, 5b2 and the inner peripheral end plate flat portion 3a2, 5a2, and leakage is less than that of the inclined portion. Therefore, it is possible to prevent high-pressure refrigerant from leaking from the innermost first compression chamber 12, which is the compression chamber with the highest pressure and is formed at the timing of communication with the discharge port, through the tip clearance into other compression chambers located on the outer periphery, thereby improving efficiency.

The above-mentioned effect is shown in Fig. 9. In the figure, the horizontal axis represents the orbital angle of the orbiting scroll 5, and the vertical axis represents the internal pressure. The internal pressure means the pressure inside the closed compression chamber.
In the figure, the dashed line indicates the compression process of Comparative Example 1, which is considered ideal in that no leakage occurs at the tip gap. The dashed line indicates Comparative Example 2, in which an inclined portion is provided up to the first compression chamber 12. The solid line indicates the case in which the first compression chamber 12 is formed only by the flat portions 3a2, 3b2, 5a2, and 5b2, as in this embodiment.
As can be seen from the figure, in Comparative Example 2, the leakage in the first compression chamber 12 is relatively large, so the maximum in-cylinder pressure is reached after the swirl angle is more advanced than in Comparative Example 1 and this embodiment. In this embodiment, the maximum in-cylinder pressure is reached after the swirl angle is more advanced than in Comparative Example 1, which has no tip gap leakage, but since there is less tip gap leakage in the first compression chamber 12 than in Comparative Example 2, the maximum in-cylinder pressure can be reached at an earlier swirl angle than in Comparative Example 2.

The number of turns of the walls 3b and 5b is determined so that the second compression chamber 14 is formed on the outer periphery of the innermost first compression chamber 12. Since the second compression chamber 14, which is a closed compression space, is formed on the outer periphery of the first compression chamber 12, even if fluid leaks from the first compression chamber 12 to the second compression chamber 14, it will not flow out to the outside (suction side) of the scroll compressor 1, thereby suppressing a decrease in efficiency.

Since the second compression chamber 14 is a closed space, the injection effect can be effectively achieved by supplying fluid from the injection port 10.

The regions in which the innermost flat portions 3a2, 3b2, 5a2, and 5b2 are formed can be modified as shown in FIG. 11B or FIG. 11C.
As shown in Fig. 11B, the outer peripheral positions of the innermost flat parts 3a2, 3b2, 5a2, 5b2 may be provided on the inner peripheral side in the spiral direction from the reference outer peripheral positions on the reference outer peripheral lines L1, L2 shown in Fig. 11A. Specifically, the outer peripheral positions of the flat parts 3a2, 3b2, 5a2, 5b2 may be provided on the reference outer peripheral lines L1', L2' rotated 90° (-90°) around the center of the end plates 3a, 5a, on the inner peripheral side in the spiral direction from the reference outer peripheral lines L1, L2. As a result, a part of the inclined parts 3a1, 3b1, 5a1, 5b1 is formed within the range of the first compression chamber 12, and there is a risk of fluid leakage due to the inclined parts 3a1, 3b1, 5a1, 5b1 present in the first compression chamber 12. However, since the start positions on the inner circumference side of the inclined portions 3a1, 3b1, 5a1, 5b1 are set on the inner circumference side of the reference outer circumference position, when trying to obtain the same inclination height (corresponding to the height difference h in FIG. 5), the dimension of the entire inclined portions 3a1, 3b1, 5a1, 5b1 in the spiral direction can be increased. By increasing the dimension of the inclined portions 3a1, 3b1, 5a1, 5b1 in the spiral direction, the inclination φ of the inclined portions 3a1, 3b1, 5a1, 5b1 can be reduced, so that leakage from the inclined portions 3a1, 3b1, 5a1, 5b1 can be suppressed. In this way, compared to FIG. 11A in which the outer circumference positions of the innermost flat portions 3a2, 3b2, 5a2, 5b2 are set at the reference outer circumference position, although the leakage from the inclined portions 3a1, 3b1, 5a1, 5b1 is increased, the leakage from the inclined portions 3a1, 3b1, 5a1, 5b1 can be reduced. Therefore, it is preferable that the lower limit of the outer circumferential position of the flat portions 3a2, 3b2, 5a2, 5b2 is set to 90° on the inner circumferential side in the spiral direction from the reference outer circumferential position.

As shown in Fig. 11C, the outer peripheral positions of the innermost flat portions 3a2, 3b2, 5a2, 5b2 may be provided on the outer periphery side in the spiral direction from the reference outer peripheral positions on the reference outer peripheral lines L1, L2 shown in Fig. 11A. Specifically, the outer peripheral positions of the flat portions 3a2, 3b2, 5a2, 5b2 may be provided on the reference outer peripheral lines L1", L2", which are rotated 90° (+90°) around the center of the end plates 3a, 5a, on the outer periphery side in the spiral direction from the reference outer peripheral lines L1, L2. As a result, since the inclined portions 3a1, 3b1, 5a1, 5b1 do not exist within the range of the first compression chamber 12, leakage of fluid from the first compression chamber 12 can be suppressed. However, if the same inclination height (corresponding to the height difference h in FIG. 5) is obtained by setting the start position on the inner circumference side of the inclined portions 3a1, 3b1, 5a1, 5b1 on the outer circumference side of the reference outer circumference position, the dimension of the inclined portions 3a1, 3b1, 5a1, 5b1 in the spiral direction as a whole will be reduced. If the dimension of the inclined portions 3a1, 3b1, 5a1, 5b1 in the spiral direction is reduced, the inclination φ of the inclined portions 3a1, 3b1, 5a1, 5b1 will be increased, so there is a risk of the occurrence of fluid leakage from the inclined portions 3a1, 3b1, 5a1, 5b1 increasing. Thus, compared to FIG. 11B in which the outer circumference positions of the innermost flat portions 3a2, 3b2, 5a2, 5b2 are set on the inner circumference side of the reference outer circumference position, the leakage from the inclined portions 3a1, 3b1, 5a1, 5b1 will be increased, but the fluid leakage from the first compression chamber 12 can be reduced. Therefore, it is preferable to set the upper limit of the outer peripheral position of the flat portions 3a2, 3b2, 5a2, and 5b2 to 90° toward the outer periphery in the spiral direction from the reference outer peripheral position.

In addition, in this embodiment, the end plate inclined portions 3a1, 5a1 and the wall body inclined portions 3b1, 5b1 are provided on both scrolls 3, 5, but they may be provided on only one of them.
Specifically, as shown in FIG. 10A, when a wall inclined portion 5b1 is provided on one wall (e.g., the orbiting scroll 5) and an end plate inclined portion 3a1 is provided on the other end plate 3a, the other wall and the one end plate 5a may be flat.
Also, as shown in FIG. 10B , a shape may be combined with a conventional stepped shape, i.e., a shape in which an end plate inclined portion 3a1 is provided on the end plate 3a of the fixed scroll 3 while a stepped portion is provided on the end plate 5a of the orbiting scroll 5.

In this embodiment, a scroll compressor has been described, but the present disclosure can also be applied to a scroll expander used as an expander.

The scroll fluid machines according to the above-described embodiments can be understood, for example, as follows.
A scroll fluid machine (1) according to one aspect of the present disclosure includes a first scroll member (3) having a first end plate (3a) on which a spiral-shaped first wall body (3b) is provided, a second scroll member (5) having a second end plate (5a) arranged to face the first end plate and having a spiral-shaped second wall body (5b) on which the second wall body engages with the first wall body to perform a relative orbital motion, and a distance between the opposing surfaces of the first end plate and the second end plate that face each other is set to be equal to or larger than the outer periphery of the first wall body and the second wall body. The wall includes an inclined portion (3a1, 5a1) that decreases continuously from the circumferential side toward the inner circumferential side, a wall flat portion (3b2, 5b2) that is provided on the innermost circumferential portion of at least one of the first wall and the second wall and has a constant height, an end plate flat portion (3a2, 5a2) that is provided on the innermost circumferential portion of at least one of the first end plate and the second end plate and corresponds to the wall flat portion, and a wall flat portion (3a2, 5a2) that has a height that is continuous from the wall flat portion toward the outer circumferential side to form the inclined portion. a wall inclined portion (3b1, 5b1) which gradually increases in angle with respect to the inner circumference of the end plate flat portion, an end plate inclined portion (3a1, 5a1) in which a tooth bottom surface facing the tooth tip of the wall inclined portion is inclined from the end plate flat portion toward the outer periphery in accordance with the inclination of the wall inclined portion, a tip seal (7) which is provided in a groove formed in the wall flat portion and the tooth tip of the wall inclined portion and contacts the facing tooth bottom to seal a fluid, and a high pressure port (3c) which is formed in the center of the first end plate or the second end plate and through which a compressed high pressure fluid or a high pressure fluid introduced from the outside flows, wherein the wall flat portion and the end plate flat portion are provided over a range from an innermost peripheral position on the high pressure port side to an outer periphery position, and the outer periphery position is provided in a range from 90° on the inner circumference side to 90° on the outer circumference side in the spiral direction of the first wall body and the second wall body, when an outer periphery position which defines the range of a first compression chamber (12) formed on the innermost circumference at the timing of communication with the high pressure port is taken as a reference outer periphery position.

Since an inclined portion is provided in which the distance between the opposing faces of the first end plate and the second end plate decreases continuously from the outer periphery to the inner periphery of the wall, the fluid sucked in from the outer periphery is not only compressed as the compression chamber decreases according to the spiral shape of the wall as it moves toward the inner periphery, but is also further compressed as the distance between the opposing faces of the end plates decreases, making it possible to compress the fluid in three dimensions and to achieve a compact design.
The inclined portion is designed to decrease continuously, and thus it is possible to reduce fluid leakage compared to a conventional stepped scroll fluid machine in which steps are provided on the wall body and the tooth bottom.

A continuous inclined portion is not limited to a smoothly connected inclined portion, but also includes a portion in which small steps are connected in a staircase-like manner, and which, when viewed as a whole, appears to be inclined continuously.

By providing a wall inclined portion in which the height of the wall increases from the inner circumference side to the outer circumference side, and an end plate inclined portion in which the tooth bottom surface facing the tooth tip of this wall inclined portion is inclined according to the inclination of the wall inclined portion, it is possible to form an inclined portion in which the distance between the opposing surfaces of the end plates decreases from the outer circumference side to the inner circumference side.

The wall inclined portion and the end plate inclined portion may be provided on the first scroll and the second scroll, or on only one of them. When a wall inclined portion is provided on one wall and an end plate inclined portion is provided on the other end plate, the other wall and the one end plate may be flat, or may be a shape combined with a conventional stepped shape.

When the two scroll members revolve relative to one another, the inclined portion shifts the positions of the tooth tips and tooth bottoms by the orbital diameter (orbital radius x 2). This shift in position between the tooth tips and tooth bottoms causes a change in the gap between the tooth tips and tooth bottoms (tip clearance). To prevent fluid leakage due to the effect of this change in tip clearance, tip seals are provided at the tooth tips of each wall corresponding to the inclined portion.

After providing the tip seal, a flat portion is provided on the innermost periphery of the wall body and the end plate in a range from the innermost periphery position on the high pressure port side to the outer periphery position. The outer periphery position of the flat portion is provided in a range from 90° on the inner periphery side to 90° on the outer periphery side in the spiral direction of the first wall body and the second wall body from the reference outer periphery position, assuming that the outer periphery position that defines the range of the first compression chamber formed on the innermost periphery at the timing when the wall body flat portion and the end plate flat portion are connected to the high pressure port is the reference outer periphery position. In this disclosure, "a compression chamber is formed" means that a compression space closed by both scroll members is formed.

Between the flat wall portion and the flat end plate portion, unlike the inclined portion, the tip clearance does not change according to the turning angle, and there is less leakage compared to the inclined portion. Therefore, by matching the outer peripheral position of the flat portion with the reference outer peripheral position, it is possible to prevent high-pressure fluid from leaking from the innermost first compression chamber, which is the compression chamber with the highest pressure and is formed when the high-pressure port is connected, through the tip gap into other compression chambers located on the outer periphery, thereby improving efficiency.

If the outer peripheral position of the flat portion is located on the inner peripheral side in the spiral direction of the reference outer peripheral position, a part of the inclined portion will be formed within the range of the first compression chamber. Therefore, there is a risk of fluid leakage due to the inclined portion existing in the first compression chamber. However, by locating the starting position on the inner peripheral side of the inclined portion more inward than the reference outer peripheral position, the dimension of the entire inclined portion in the spiral direction can be increased when attempting to obtain the same inclination height. By increasing the dimension of the inclined portion in the spiral direction, the inclination of the inclined portion can be reduced, thereby suppressing leakage from the inclined portion. Therefore, the lower limit of the outer peripheral position of the flat portion is set to 90° on the inner peripheral side in the spiral direction of the reference outer peripheral position.

When the outer peripheral position of the flat portion is set within a range of 90° on the outer peripheral side of the reference outer peripheral position in the spiral direction, there is no inclined portion within the range of the first compression chamber, so fluid leakage from the first compression chamber can be suppressed. However, if an attempt is made to obtain the same inclination height by setting the start position on the inner peripheral side of the inclined portion outer peripherally than the reference outer peripheral position, the dimension of the inclined portion in the spiral direction as a whole becomes smaller. If the dimension of the inclined portion in the spiral direction becomes smaller, the inclination of the inclined portion becomes larger, and there is a risk of increasing the occurrence of fluid leakage from the inclined portion. Therefore, the upper limit of the outer peripheral position of the flat portion is set to 90° on the outer peripheral side of the reference outer peripheral position in the spiral direction.

In a scroll fluid machine according to one aspect of the present disclosure, a second compression chamber (14) is formed on the outer periphery of the first compression chamber, which is formed at the timing of communication with the high-pressure port.

The number of turns of the first wall and the second wall is determined so that a second compression chamber is formed located on the outer periphery of the first compression chamber at the innermost periphery. Since the second compression chamber, which is a closed compression space, is formed on the outer periphery of the first compression chamber, even if fluid leaks from the first compression chamber to the second compression chamber, it will not flow out to the outside of the scroll fluid machine, thereby suppressing a decrease in efficiency.

In addition, in the scroll fluid machine according to one embodiment of the present disclosure, an injection port (10) is provided to supply fluid into the second compression chamber.

Since the second compression chamber is a closed space, the injection effect can be effectively achieved by supplying fluid from the injection port. A scroll fluid machine equipped with an injection port is preferably used as a compressor that compresses refrigerant in a refrigeration cycle, and the refrigerant is guided through it after passing through the condenser.

1. Scroll compressor (scroll fluid machine)
3 Fixed scroll (first scroll member)
3a End plate (first end plate)
3a1 End plate inclined portion 3a2 Inner circumferential side end plate flat portion 3a3 Outer circumferential side end plate flat portion 3a4 End plate inclined connection portion 3b Wall body (first wall body)
3b1 wall inclined portion 3b2 inner peripheral side wall flat portion 3b3 outer peripheral side wall flat portion 3b4 wall inclined connection portion 3c discharge port (high pressure port)
3d Tip seal groove 5 Orbiting scroll (second scroll member)
5a End plate (second end plate)
5a1: End plate inclined portion 5a2: Inner peripheral side end plate flat portion 5a3: Outer peripheral side end plate flat portion 5a4: End plate inclined connection portion 5b: Wall body (second wall body)
5b1 Wall inclined portion 5b2 Inner peripheral side wall flat portion 5b3 Outer peripheral side wall flat portion 5b4 Wall inclined connection portion 5b6 Outermost peripheral end 7 Tip seal 10 Injection port 12 First compression chamber L Distance between opposing surfaces L1, L2 Reference outer peripheral line T Tip clearance φ Inclination

Claims (3)

a first scroll member having a first end plate and a first wall body formed on the first end plate;
a second scroll member having a second wall body in a spiral shape provided on a second end plate disposed opposite the first end plate, the second wall body engaging with the first wall body to perform a relative orbital motion;
an inclined portion in which a distance between opposing surfaces of the first end plate and the second end plate facing each other continuously decreases from an outer circumferential side to an inner circumferential side of the first wall body and the second wall body;
a flat wall portion provided on an innermost peripheral portion of at least one of the first wall portion and the second wall portion, the flat wall portion having a constant height;
an end plate flat portion provided on an innermost periphery of at least one of the first end plate and the second end plate and corresponding to the wall flat portion;
a wall inclined portion in which the height of the wall forming the inclined portion increases continuously from the wall flat portion toward the outer periphery to form the inclined portion;
an end plate inclined portion in which a tooth bottom surface facing the tooth tip of the wall inclined portion is inclined from the end plate flat portion toward an outer periphery in accordance with an inclination of the wall inclined portion;
a tip seal provided in a groove formed on the tooth tips of the wall flat portion and the wall inclined portion, the tip seal contacting the opposing tooth bottom to seal a fluid;
a high pressure port formed at the center of the first end plate or the second end plate, through which a compressed high pressure fluid or a high pressure fluid introduced from the outside flows;
Equipped with
the wall flat portion and the end plate flat portion are provided over a range from an innermost peripheral position to an outer peripheral position on the high pressure port side, and in a region that is 360° or more (excluding 360°) around a center of the scroll member in which the wall flat portion and the end plate flat portion are provided ,
The scroll fluid machine has an outer circumferential position that is located in a range from 90° on the inner circumferential side to 90° on the outer circumferential side in the spiral direction of the first wall body and the second wall body from the reference outer circumferential position, when the outer circumferential position that defines the range of a first compression chamber formed at the innermost circumference at the time of communication with the high pressure port is taken as a reference outer circumferential position. The scroll fluid machine according to claim 1, in which a second compression chamber is formed at the timing of communication with the high-pressure port and located on the outer periphery side of the first compression chamber. The scroll fluid machine according to claim 2, further comprising an injection port for supplying fluid into the second compression chamber.