JP6180860B2 - Scroll compressor - Google Patents

Description

  The present invention relates to a so-called stepped scroll compressor in which a step portion is provided at a position along the spiral direction of a fixed scroll and a turning scroll.

  Step portions are provided at positions along the spiral direction of the tooth tip surface and the tooth bottom surface of the spiral wrap of the fixed scroll and the orbiting scroll, and the wrap height on the outer peripheral side of the spiral wrap is the inner peripheral side with the step portion as a boundary. The stepped scroll compressor, which is higher than the wrap height of the wrap, is compressed not only in the circumferential direction of the spiral wrap but also in the wrap height direction (three-dimensional compression). Compared with a simple scroll compressor (two-dimensional compression), the displacement can be increased and the compressor capacity can be increased. Therefore, it is possible to reduce the size and weight by increasing the compression ratio and improving the performance without increasing the outer diameter of the compressor.

  In such a stepped scroll compressor, when the pressure in the compression chamber rises due to operating conditions and the pressure exceeds the set pressure before communicating with the discharge port, the compressed gas is passed through the bypass port and bypass valve to the discharge chamber. Patent Document 1 discloses a stepped scroll compressor provided with an overcompression preventing mechanism for releasing. Further, in Patent Document 2, the spiral wraps mesh with each other at the stepped portion, and the root of the stepped portion is caused by stress concentration on the root of the stepped portion on the tooth tip surface side due to contact between the wraps on the tooth tip side. In order to eliminate the situation of breakage, a thinning portion for avoiding contact between the wraps is provided in a predetermined meshing range from at least the meshing start position of one or both of the stepped portions on the tooth tip surface side or the tooth bottom surface side. Are disclosed.

  On the other hand, in a scroll compressor not provided with a step portion, the compressed gas is discharged from the compression chamber side to the discharge chamber side at a position where the operating pressure ratio of the compression chamber is 0.5 to 0.75 of the set pressure ratio. Patent Document 3 discloses a bypass port provided with a bypass valve that is allowed to reduce power loss due to overcompression. In Patent Document 4, at least four relief ports and one discharge port are provided between a compression chamber formed by both scrolls and a discharge chamber, and a relief valve is provided at each port. One is disclosed in which one of the ports or the discharge port is always in communication with the compression chamber so that liquid compression and overcompression can be prevented throughout the entire compression stroke.

JP 2009-287512 A JP 2013-36366 A Japanese Unexamined Patent Publication No. 63-140884 JP 2000-345976 A

  However, in any of the above-mentioned Patent Documents 1 to 4, attention is paid to the stepped portion on the tooth bottom side of the spiral wrap in the stepped scroll compressor, and the engagement is terminated at least from the position (θs) at which the stepped portion starts to engage. In the range up to the position (θs + π), over compression and liquid compression are surely prevented, and the stepped part on the tip of the spiral wrap receives excessive differential pressure due to over compression and liquid compression. There is no description of a technique that attempts to eliminate the situation where the root of the step portion is damaged due to the stress concentration on the root portion of the step portion due to pressure.

  As described above, at present, the spiral wraps of the fixed scroll and the orbiting scroll of the stepped scroll compressor are engaged with each other at the stepped portion, and in this state, the swirl is caused by excessive compression or liquid compression. In fact, the countermeasures against stress concentration at the root of the stepped portion on the tooth tip surface side of the wrapping wrap cannot be said to have been sufficiently taken, and the durability and reliability have not been ensured.

  The present invention has been made in view of such circumstances, and is based on fixing of a so-called stepped scroll compressor and overcompression or liquid compression on the root portion of the stepped side of the spiral wrap of the orbiting scroll. An object of the present invention is to provide a scroll compressor that avoids stress concentration and reliably eliminates the situation where the base of the step portion is damaged, thereby improving durability and reliability.

In order to solve the above problems, the scroll compressor of the present invention employs the following means.
That is, the scroll compressor according to the present invention is provided with stepped portions at positions along the spiral direction of the tooth tip surface and the tooth bottom surface of the spiral wrap of the fixed scroll and the orbiting scroll, and the spiral shape with the step portion as a boundary. In the scroll compressor in which the wrap height on the outer peripheral side of the wrap is higher than the wrap height on the inner peripheral side, the mesh is engaged at least from the position (θs) at which the stepped portion starts to mesh with the tooth bottom surface side of the fixed scroll. At least one or more bypass ports that are opened in the range up to the end position (θs + π) and that are opened when the pressure in the compression chamber is overcompressed to a set pressure or more are provided.

  According to the present invention, there is provided a so-called stepped scroll compressor in which step portions are provided at positions along the spiral direction of the tooth tip surface and the tooth bottom surface of the spiral wraps of the fixed scroll and the orbiting scroll, respectively. When the pressure in the compression chamber is overcompressed to a set pressure or higher, at least in the range from the position (θs) at which the step portion starts meshing to the position (θs + π) at which meshing ends (θs + π). Since at least one bypass port to be opened is provided, a position (θs + π) where the engagement ends from the position (θs) where the stepped portions provided on the tooth tip surface and the tooth bottom surface of the spiral wrap start to engage. In the range up to), when the pressure in the compression chamber rises due to over-compression or liquid compression and exceeds the set pressure, by opening the bypass port, Condensation chamber of the compressed gas can be a relieved the discharge chamber. Therefore, excessive stress due to over-compression or liquid compression is applied to the root part of the step part on the tooth tip surface side of the spiral wrap, and the situation that the root part is damaged is surely eliminated. Performance and reliability can be improved, and power loss due to overcompression can be reduced.

  Furthermore, in the scroll compressor according to the present invention, in the scroll compressor described above, in addition to the bypass port, the range is from a suction closing position (θd) of the compression chamber to a position (θs) where the stepped portion starts to engage. And at least one second bypass port that is opened when the pressure in the compression chamber is overcompressed to a set pressure or higher.

  According to the present invention, in addition to the bypass port, the compression chamber is opened in the range from the suction closing position (θd) of the compression chamber to the position (θs) where the step portion starts to engage, and the pressure of the compression chamber exceeds the set pressure. Since at least one second bypass port that is opened when compressed is provided, the engagement on the outer peripheral side of the stepped portion where the height of the spiral wrap is increased, that is, the suction cutoff of the compression chamber In the meshing from the position (θd) to the position (θs) where the step portion starts meshing, when the pressure in the compression chamber rises due to overcompression or liquid compression and exceeds the set pressure, the second bypass port is By opening, the compressed gas in the compression chamber can be relieved to the discharge chamber. Therefore, sufficient strength of the spiral wrap is ensured even on the outer periphery side of the step part where the strength is weakened by increasing the wrap height, and durability and reliability can be secured, and power loss is reduced. can do.

  Furthermore, in the scroll compressor according to any one of the above-described scroll compressors, in addition to the bypass port, a position where the compression chamber communicates with the discharge port from a position (θs + π) where the stepped portion has finished meshing. At least one or more third bypass ports that are opened in a range up to (θp) and that are opened when the pressure in the compression chamber is overcompressed to a set pressure or higher are provided.

  According to the present invention, in addition to the bypass port, the compression chamber is opened in a range from the position (θs + π) where the stepped portion has finished meshing to the position (θp) where the compression chamber communicates with the discharge port, and the pressure of the compression chamber is set. Position where the compression chamber communicates with the discharge port from the position (θs + π) where the meshing at the stepped portion is completed because at least one third bypass port is provided that is opened when the pressure is overcompressed to the pressure or higher. Even in the meshing range up to (θp), when the pressure in the compression chamber rises due to over-compression or liquid compression and exceeds the set pressure, the compressed gas in the compression chamber is discharged by opening the third bypass port. Relief to the room. Therefore, over the entire compression stroke including the range in which the pressure in the compression chamber rises most due to overcompression or liquid compression, the compressed gas whose pressure is abnormally increased is reliably relieved to the discharge chamber to prevent overcompression and liquid compression. In addition, durability and reliability can be ensured, and power loss can be reduced.

  Furthermore, in the scroll compressor according to any one of the above-described scroll compressors, the step portion is opened in a range from a position (θs) at which the step portion starts to mesh to a position (θs + π) at which meshing ends. The total opening area of the bypass port is larger than the opening area of the second bypass port or the third bypass port opened in another range.

  According to the present invention, the total opening area of the bypass port opened in the range from the position (θs) at which the step portion starts meshing to the position (θs + π) at which meshing ends is opened in another range. Since the opening area of the second bypass port or the third bypass port is larger than that of the second bypass port, the total opening area of the bypass ports that are opened in the range where the stepped portion is meshed is increased, and when overcompression or liquid compression occurs, Refrigerant gas in the compression chamber whose pressure has abnormally increased can be quickly relieved to the discharge chamber, and over-compression or liquid compression can be more reliably prevented in the section where the stepped portions mesh. Therefore, it is possible to more reliably avoid stress concentration due to over-compression or liquid compression on the root portion of the stepped side of the spiral wrap, and to further improve the durability and reliability of the stepped scroll compressor. .

  Furthermore, in the scroll compressor according to the present invention, in the scroll compressor described above, the total opening area is increased by increasing the number of ports of the bypass port than the number of ports of the second or third bypass port. It is characterized by.

  According to the present invention, since the total opening area is increased by increasing the number of bypass ports more than the number of ports of the second or third bypass ports, generally the diameter of this type of port is a predetermined diameter. Although limited to the following, the total opening area can be easily increased by increasing the number of bypass ports. Therefore, by increasing the number of bypass ports provided in the section where the stepped portion meshes and increasing the total opening area, it becomes possible to more reliably prevent over-compression and liquid compression in the section engaging the stepped portion. .

  Furthermore, in the scroll compressor according to the present invention, in the scroll compressor described above, a port area per one of the bypass ports is made larger than a port area per one of the second or third bypass ports. Thus, the total opening area is increased.

  According to the present invention, since the port area per one bypass port is made larger than the port area per one second or third bypass port, the total opening area is increased. When the diameter of each of the bypass ports is limited to a predetermined diameter or less, the total opening area of the bypass ports can be easily increased even when the same number of ports are provided by changing the port area per one. Therefore, by increasing the port area per bypass port provided in the section where the stepped portion meshes and increasing the total opening area, it is possible to more reliably prevent over-compression and liquid compression in the section engaging the stepped portion. Is possible.

  Furthermore, in the scroll compressor according to the present invention, in any of the scroll compressors described above, the bypass port, the second bypass port, and the third bypass port are each provided with a reed valve that is opened above a set pressure. It is characterized by being.

  According to the present invention, since the bypass port, the second bypass port, and the third bypass port are each provided with the reed valve that is opened at a pressure higher than the set pressure, overcompression and liquid are performed at the position where each bypass port is provided. When the pressure in the compression chamber rises due to compression and the pressure exceeds the set pressure of the reed valve provided in each bypass port, the reed valve opens and each bypass port can be opened to the discharge chamber. . Therefore, each reed valve can easily open each bypass port above the set pressure to relieve the compressed gas to the discharge chamber.

  Furthermore, in the scroll compressor according to the present invention, in the scroll compressor described above, when the reed valve is provided with two or more of each of the bypass port, the second bypass port, and the third bypass port. The plurality of ports are installed close to each other so that they can be opened and closed by one common reed valve.

  According to the present invention, when the reed valve is provided with two or more of each of the bypass port, the second bypass port and the third bypass port, by installing the plurality of ports close to each other, Since it can be opened and closed by one common reed valve, if the number of bypass ports is increased, it is necessary to increase the number of reed valves accordingly. The number of reed valves can be reduced with respect to the number of bypass ports. Therefore, the installation of the reed valve in a narrow space can be facilitated, and the function of preventing over-compression and liquid compression can be improved by increasing the number of bypass ports.

  Furthermore, in the scroll compressor according to the present invention, in any one of the above-described scroll compressors, each of the step portions includes a plurality of steps, and the bypass port engages with the first step of the plurality of steps. It is provided so that it may open in the range from the position ((theta) s) which starts to the position ((theta) s + (pi)) where the last stage complete | finishes meshing | engagement.

  According to the present invention, each step portion is composed of a plurality of steps, and the bypass port is a position where the first step of the plurality of steps starts to engage (θs) and the final step ends the engagement. Since it is provided to be opened in the range up to (θs + π), each step portion provided on the tooth tip surface and the tooth bottom surface of the spiral wrap of the fixed scroll and the orbiting scroll is configured with a plurality of steps (for example, Even in the case where each step portion is composed of two steps) from the position (θs) at which the first step of the plurality of steps of each step portion provided on the tooth tip surface and the tooth bottom surface of the spiral wrap starts to mesh. By opening the bypass port when the pressure in the compression chamber rises due to over-compression or liquid compression and exceeds the set pressure in the range up to the position (θs + π) where the final stage finishes meshing It is possible to relief the compressed gas in the compression chamber to the discharge chamber. In this case, the durability and reliability of the stepped scroll compressor against over-compression and liquid compression can be further improved by a synergistic effect with the effect of improving the lap strength by configuring each step portion with a plurality of steps. .

  According to the present invention, in the range from the position (θs) where the step portions provided on the tooth tip surface and the tooth bottom surface of the spiral wrap of the fixed and orbiting scroll start meshing to the position (θs + π) where meshing ends. When the pressure in the compression chamber rises due to overcompression or liquid compression and exceeds the set pressure, the compressed gas in the compression chamber can be relieved to the discharge chamber by opening the bypass port. Improves the durability and reliability of the stepped scroll compressor by eliminating excessive stress caused by over-compression or liquid compression on the root of the stepped portion on the tip of the tooth surface. And power loss due to overcompression can be reduced.

It is a longitudinal section of the scroll compressor concerning a 1st embodiment of the present invention. It is an AA cross-section equivalent view of FIG. It is compression operation explanatory drawing which shows the change of the fixed state of the said scroll compressor, and the meshing state of a turning scroll. It is an expanded view which shows the opening range of the bypass port in the said scroll compressor. It is the graph (A) which shows the stress measurement result of the step part by the side of the tooth-tip surface of the spiral wrap in the said scroll compressor, and the action state explanatory drawing (B) of the stress. It is an AA cross section equivalent figure in Drawing 1 of a scroll compressor concerning a 2nd embodiment of the present invention. It is an AA cross section equivalent figure in Drawing 1 of a scroll compressor concerning a 2nd embodiment of the present invention. FIG. 8 is a structural explanatory view of a reed valve provided in a bypass port of the scroll compressor shown in FIGS. 6 and 7. FIG. 8 is a development view (A) to (D) showing an opening range of a bypass port in the scroll compressor shown in FIGS. 6 and 7.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 5.
FIG. 1 is a longitudinal sectional view of a scroll compressor according to the first embodiment of the present invention, FIG. 2 is a cross-sectional view corresponding to the AA cross section thereof, and FIG. Has been.
The scroll compressor 1 has a housing 2 that constitutes an outer shell thereof. The housing 2 comprises a bottomed cup-shaped housing 3 sealed at one end and a front housing 4 fitted and mounted on the open end side thereof, and is configured by fastening and fixing them together with bolts or the like. Has been.

A crankshaft 5 is supported inside the front housing 4 via a main bearing 6 and a sub-bearing 7 so as to be rotatable about its axis. One end side (left end side in FIG. 1) of the crankshaft 5 is a small-diameter shaft portion 5A, and the small-diameter shaft portion 5A passes through the front housing 4 and protrudes to the left in FIG. The protruding portion of the small-diameter shaft portion 5A is provided with an electromagnetic clutch, a pulley (not shown) that receives power as is well known, and power is transmitted from a drive source such as an engine via a belt or the like. A lip seal 8 is installed between the main bearing 6 and the sub-bearing 7 to seal between the housing 2 and the atmosphere.

  A large-diameter shaft portion 5B is provided on the other end side (right end side in FIG. 1) of the crankshaft 5. The large-diameter shaft portion 5B has a crank pin 5C that is eccentric from the axis of the crankshaft 5 by a predetermined dimension. It is provided integrally. The crankshaft 5 is rotatably supported by the front housing 4 by supporting the large-diameter shaft portion 5B and the small-diameter shaft portion 5A via the main bearing 6 and the sub-bearing 7. A crank scroll 5 is connected to a crank pin 5C via a drive bush 9 and a swing bearing 10, and the swing scroll 14 is driven to rotate when the crank shaft 5 is rotated.

  The drive bush 9 is provided with a pin hole 9A for fitting the crank pin 5C, and the boss portion 14 of the orbiting scroll 14 is fitted to the outer periphery of the drive bush 9 fitted to the crank pin 5C via the orbiting bearing 10. By doing so, the crankpin 5C and the orbiting scroll 14 are connected. A known driven crank mechanism that makes the turning radius of the orbiting scroll 14 variable can be provided between the drive bush 9 and the crankpin 5C. Further, the drive bush 9 is provided with a balance weight 11 for removing an unbalanced load generated when the turning scroll 14 is turned, and is driven to turn together with the turning scroll 14.

  A scroll compression mechanism (compression mechanism) 12 constituted by a pair of fixed scroll 13 and orbiting scroll 14 is incorporated in the housing 2. The fixed scroll 13 is composed of an end plate 13A and a spiral wrap 13B standing from the end plate 13A, and the orbiting scroll 14 is standing from the end plate 14A and the end plate 14A. And a spiral wrap 14B.

  The fixed scroll 13 and the orbiting scroll 14 of the present embodiment are stepped portions 13D, 13E and 14D, 14E (see FIG. 2) at predetermined positions along the spiral directions of the tooth tip surfaces and the tooth bottom surfaces of the spiral wraps 13B, 14B, respectively. ). With the stepped portions 13D, 13E and 14D, 14E as a boundary, the tooth tip surfaces of the spiral wraps 13B, 14B have a high tooth tip surface on the outer peripheral side in the swivel axis direction and a lower tooth tip surface on the inner peripheral side. The tooth bottom surface has a lower tooth bottom surface on the outer peripheral side in the pivot axis direction and a higher tooth bottom surface on the inner peripheral side. Accordingly, the spiral wraps 13B and 14B have a wrap height on the outer peripheral side higher than a wrap height on the inner peripheral side.

  The fixed scroll 13 and the orbiting scroll 14 are separated from each other by the orbiting radius, and the phases of the spiral wraps 13B and 14B are shifted by 180 degrees to engage with each other. The tooth tip surfaces and the tooth bottom surfaces of the spiral wraps 13B and 14B of both scrolls. It is assembled so as to have a slight clearance in the lap height direction at room temperature. As a result, as shown in FIG. 1, a pair of compression chambers 15 limited by the end plates 13A and 14A and the spiral wraps 13B and 14B are symmetrical between the scrolls 13 and 14 with respect to the scroll center. In addition, the orbiting scroll 14 can be smoothly orbited around the fixed scroll 13.

  The compression chamber 15 wraps the gas not only in the circumferential direction of the spiral wraps 13B and 14B but also in the circumferential direction of the spiral wraps 13B and 14B by making the height in the swirling axis direction higher than the height on the outer peripheral side of the spiral wraps 13B and 14B. A three-dimensional compressible scroll compression mechanism 12 that can also compress in the height direction is configured. Note that tip seals 16 for sealing the tip seal surface formed between the tooth bottom surfaces of the other scrolls are provided on the tooth tip surfaces of the spiral wraps 13B and 14B in the grooves provided on the tooth tip surfaces, respectively. It is fitted and installed. The stepped scroll compressor 1 having such a configuration is a known one.

  The fixed scroll 13 is fixedly installed on the inner bottom surface of the cup-shaped housing 3 via a plurality of bolts 17. Further, in the orbiting scroll 14, the crank pin 5C provided on one end side of the crankshaft 5 is connected to the drive bush 9 and the orbiting bearing 10 with respect to the boss portion 14C provided on the back surface of the end plate 14A as described above. And are configured to be pivotally driven.

  Further, the orbiting scroll 14 is supported by the thrust bearing surface of the front housing 4 on the back surface of the end plate 14A, and a rotation preventing mechanism 18 such as an Oldham ring provided between the thrust bearing surface and the back surface of the end plate 14A. The rotation is driven around the fixed scroll 13 while being prevented from rotating. The rotation prevention mechanism 18 is not limited to the Oldham ring, and may be a known pin ring type rotation prevention mechanism.

  The fixed scroll 13 has a discharge port 13C that discharges compressed refrigerant gas at the central portion of the end plate 13A, and a discharge reed valve 19 is installed in the discharge port 13C via a retainer. . Further, a sealing material 20 such as an O-ring is interposed on the back side of the end plate 13 </ b> A of the fixed scroll 13 so as to be in close contact with the inner surface of the cup-shaped housing 3. A discharge chamber 21 partitioned from the internal space 2 is formed. As a result, the internal space of the housing 2 excluding the discharge chamber 21 functions as the suction chamber 22.

  In the stepped scroll compressor 1, when overcompression or liquid compression occurs depending on the operation state, the stepped portions 13D and 14D on the tooth tip surface side of the spiral wraps 13B and 14B of the fixed scroll 13 and the orbiting scroll 14 are used. Excessive stress due to overcompression or liquid compression may be applied to the root, and the stress concentration may cause cracks at the root of the stepped portions 13D and 14D, which may cause damage to the spiral wraps 13B and 14B. .

  Therefore, in this embodiment, at least the stepped portions 13D and 13E on the fixed scroll 13 side and the stepped portions 14D and 14E on the orbiting scroll 14 side mesh with each other, and the differential pressure in the compression chamber 15 before and after the division defined by the meshing is a tooth. In a range that acts on the stepped portions 13D and 14D on the front surface side, that is, in a range from at least a position (θs) at which the stepped portions 13D and 14E and 13E and 14D start to engage to a position (θs + π) at which engagement ends. A pair of bypass ports 23 </ b> A and 23 </ b> B that are fully open with respect to the compression chamber 15 is formed in the end plate 13 </ b> A on the fixed scroll 13 side so that the compressed gas can be relieved to the discharge chamber 21.

  The pair of bypass ports 23A and 23B are provided at least one by one with a phase shift of 180 degrees along the abdominal side surface and the back side surface of the spiral wrap 13B of the fixed scroll 13. As shown in FIG. 8, when the pressure in the compression chamber 15 becomes equal to or higher than the set pressure, the bypass ports 23A and 23B are discharged into the openings of the bypass ports 23A and 23B toward the discharge chamber 21 side. A reed valve 24 that opens to the chamber 21 is provided.

FIGS. 3A to 3D are explanatory views of a compression operation showing a change in the meshing state of the fixed scroll 13 and the orbiting scroll 14 of the stepped scroll compressor 1.
3A to 3D, FIG. 3A shows a state where the turning angle θ of the orbiting scroll 14 is 0 degree (360 degrees), and FIG. 3B shows a state where the turning angle θ is 270 degrees. FIG. (C) shows a state where the turning angle θ is 180 degrees, and FIG. (D) shows a state where the turning angle θ is 90 degrees.

  Here, FIG. 3B shows the suction closing position (θd) of the compression chamber 15, FIG. 3D shows the position (θs) at which the step portions 13D, 13E, 14D, and 14E start meshing, The position at which the turning angle θ is 280 degrees advanced by 10 degrees from FIG. (B) is the position at which the stepped portions 13D, 13E and 14D, 14E end meshing (θs + π), and the rotation is 40 degrees before the positions in FIG. The position where the angle θ is 230 degrees is the position (θp) where the pair of compression chambers 15 join and communicate with the discharge port 13C.

  Therefore, in the present embodiment, the pair of bypass ports 23A and 23B is configured to have the step portions 13D and 13E and the step portions 13D and 13E from the position (θs) at which the turning angle θ at which the step portions 13D and 13E and 14D and 14E start to engage is 90 degrees. In a section up to the position (θs + π) at which the turning angle θ at which the engagement of 14D and 14E ends is 280 degrees (θs + π), the compression chamber 15 is fully opened, and the pressure in the compression chamber 15 is equal to or higher than the set pressure of the reed valve 24. In this case, the overcompressed gas in the compression chamber 15 can be relieved to the discharge chamber 21 via the pair of bypass ports 23A and 23B.

FIG. 4 is a development view showing a range in which the bypass ports 23A and 23B are opened with respect to the compression chamber 15. The horizontal axis indicates the turning angle θ, and the vertical axis indicates the opening area of the bypass ports 23A and 23B. Is.
In the case of the present embodiment, as described above, at least from the position (θs) at which the step portions 13D, 13E and 14D, 14E start to engage to the position (θs + π) at which the step portions 13D, 13E and 14D, 14E end the engagement. In the range (section) W, the pair of bypass ports 23A and 23B are fully opened. However, the bypass ports 23A and 23B are fully opened at a predetermined angle before the position (θs) at which meshing is started, and are gradually closed from a position after the meshing end position (θs + π).

With the configuration described above, according to the present embodiment, the following operational effects can be obtained.
In the stepped scroll compressor 1, the low-pressure refrigerant gas sucked into the suction chamber 22 in the housing 2 from the suction port (not shown) is sucked into the pair of compression chambers 15 by the turning drive of the turning scroll 14. Be turned. The refrigerant gas is three-dimensionally compressed while the compression chamber 15 is moved from the outer peripheral side to the center side while decreasing the volume in the circumferential direction of the spiral wraps 13B and 14B and the wrap height direction, and a pair of compression chambers When 15 joins and communicates with the discharge port 13 </ b> C, the discharge reed valve 19 is opened and discharged into the discharge chamber 21. The high-pressure gas is sent to the outside through a discharge port provided in the housing 2.

  In this compression process, the pressure in the compression chamber 15 may rise abnormally depending on the operating conditions, resulting in an overcompressed state, or the pressure may rise abnormally due to liquid refrigerant being sucked and liquid compressed. In this case, as shown in FIG. 5B, over compression is applied to the root portions of the stepped portions 13D and 14D on the tooth tip surfaces of the spiral wraps 13B and 14B of the fixed scroll 13 and the orbiting scroll 14. In addition, excessive stress due to liquid compression is applied, and the concentration of the stress causes cracks at the bases of the step portions 13D and 14D, which may cause damage to the spiral wraps 13B and 14B.

  However, according to the present embodiment, at least the spiral wraps 13B and 14B of the scrolls 13 and 14 on the tooth bottom surface side of the fixed scroll 13 are positioned at positions where the step portions 13D, 13E, 14D and 14E start to mesh (θs). To the position (θs + π) where the engagement ends and when the pressure in the pair of compression chambers 15 is overcompressed to a set pressure or higher, the valve is opened via the reed valve 24 (see FIG. 8). At least one bypass port 23A, 23B is provided for each compression chamber 15.

  For this reason, from the position (θs) where the step portions 13D, 13E, 14D, 14E provided on the tooth tip surfaces and the tooth bottom surfaces of the spiral wraps 13B, 14B start to mesh to the position (θs + π) where meshing ends. In the range, that is, the step meshing range (section) W shown in FIG. 4, when the pressure in the compression chamber 15 rises abnormally due to overcompression or liquid compression and rises above the set pressure, the bypass ports 23A and 23B are opened. As a result, the compressed gas in the compression chamber 15 is relieved to the discharge chamber 21 via the bypass ports 23A and 23B.

  As a result, excessive stress due to over-compression or liquid compression is applied to the root portions of the stepped portions 13D and 14D on the tooth tip surface side of the spiral wraps 13B and 14B, and the situation in which the roots are damaged is reliably eliminated. The durability and reliability of the stepped scroll compressor 1 can be improved. In addition, power loss due to overcompression can be reduced. FIG. 5A shows the measurement results of stress due to over-compression and liquid compression acting on the stepped portions 13D and 14D. When the thick solid line is without the bypass port, the thin solid line is the bypass ports 23A and 23B. This is the case of the present embodiment provided. From FIG. 5A, stress due to over-compression and liquid compression in the step meshing range (step meshing) W from the meshing start position (θs: 90 degrees) to the meshing end position (θs + π: 270 degrees). It can be seen that is significantly reduced.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.
The present embodiment is different from the first embodiment in that the second bypass ports 25A and 25B and the third bypass ports 26A and 26B are provided in the meshing range other than the meshing range W of the stepped portion. Different. Since other points are the same as those in the first embodiment, description thereof will be omitted.

  In the present embodiment, as shown in FIG. 6, in addition to the bypass ports 23A and 23B, the meshing of the fixed and swirl wraps 13B and 14B of the orbiting scrolls 13 and 14 is the suction cutoff position ( A pair of second bypasses that are opened to the compression chamber 15 in a range from θd) to the position (θs) at which the step portion starts meshing, and are opened when the pressure in the compression chamber 15 is overcompressed to a set pressure or higher. At least one port 25A, 25B is provided, and the pressure in the compression chamber 15 is equal to or higher than the set pressure, as shown in FIG. 8, in the second bypass ports 25A, 25B. A reed valve 27 that is sometimes opened is provided.

  Further, in addition to the second bypass ports 25A and 25B, positions where the compression chambers 15 join from the position (θs + π) where the stepped portions 13D, 13E, 14D and 14E have finished meshing and communicate with the discharge port 13C ( At least one pair of third bypass ports 26A, 26B that are opened to the compression chamber 15 in the range up to θp) and opened when the pressure in the compression chamber 15 is overcompressed to a set pressure or higher are provided. In this case, as shown in FIG. 8, the reed valve 28 that is opened when the pressure in the compression chamber 15 becomes equal to or higher than the set pressure is also provided in the third bypass ports 26A and 26B. .

  Further, as described above, in addition to the bypass ports 23A and 23B, the second bypass ports 25A and 25B or the third bypass ports 26A and 26B are provided so that overcompression or liquid compression can be prevented over the entire compression stroke. The total opening area of the bypass ports 23A and 23B opened in the range (section) W from the position (θs) at which the step portions 13D, 13E, 14D, and 14E start to engage to the position (θs + π) at which engagement ends The total opening area of the second bypass ports 25A and 25B or the third bypass ports 26A and 26B opened in other ranges (sections) is made larger, so that overcompression or liquid compression in the section W where the stepped portions are engaged is ensured. It can be set as the structure which can prevent.

In this case, the total opening area of the bypass ports 23A and 23B may be made larger than the total opening area of the second bypass ports 25A and 25B or the third bypass ports 26A and 26B as follows.
(1) The number of bypass ports 23A and 23B provided in the range W from the position (θs) at which the stepped portions 13D, 13E, 14D, and 14E start meshing to the position (θs + π) at which meshing ends is increased. FIG. 6 shows an example in which two bypass ports 23A and 23B are provided close to each other.

(2) The bypass ports 23A and 23B provided in the above range W are elongated holes as shown in FIG. 7, and the opening area per one is increased. This is because the opening area per port can be increased under the restriction that the diameter of one port must be smaller than the thickness of the spiral wraps 13B and 14B.
In addition, by increasing the opening area of each of the bypass ports 23A, 23B, 25A, 25B, 26A, and 26B, the flow path resistance when the compressed gas is relieved is reduced, and the compression chamber 15 is smoothly transferred to the discharge chamber 21. Compressed gas can be released.

  In addition, as described above, when a plurality of bypass ports 23A, 23B, 25A, 25B, 26A, and 26B are provided for each meshing range (section) of the spiral wraps 13B and 14B, a plurality of ports are installed close to each other ( It is desirable that the bypass ports 23A and 23B shown in FIG. Thus, by installing a plurality of ports close to each other, as shown in FIG. 8, the reed valves 24, 27, and 28 for opening and closing the plurality of ports are replaced by one common reed valve 24, 27, 28. Therefore, the number of reed valves can be halved.

  FIG. 8 shows an example in which a plurality of bypass ports 23A, 23B, 25A, 25B, 26A, and 26B are provided, and each of the reed valves 24, 27, and 28 is a common reed valve.

FIG. 9 is a development view (A) to (D) showing a range in which each bypass port in each of the above-described embodiments is open to the compression chamber 15. Indicates the opening area of each bypass port.
(A) includes a pair of bypass ports 23A and 23B that are fully opened in a range W from a position (θs) at which the step portions 13D, 13E, 14D, and 14E start meshing to a position (θs + π) at which meshing ends. When the second bypass ports 25A and 25B are provided that are fully opened in the range W2 from the suction closing position (θd) of the compression chamber 15 to the position (θs) at which the step portions 13D, 13E, 14D, and 14 start to engage with each other. Is.

  The range of W2 is a range in which the spiral wraps 13B, 14B on the outer peripheral side of the stepped portions 13D, 13E, 14D, 14E where the wrap heights of the spiral wraps 13B, 14B are increased mesh with each other. Since the lap strength is weakened by increasing the height, it is beneficial to prevent over-compression and liquid compression by providing the second bypass ports 25A and 25B.

  In (B), in addition to the bypass ports 23A, 23B and the second bypass ports 25A, 25B, a pair of compression chambers 15 join from the position (θs + π) where the step portions 13D, 13E, 14D, 14E have finished meshing, and the discharge ports. This is a case where third bypass ports 26A and 26B that are fully opened in a range W3 up to a position (θp) communicated with 13C are provided.

(C) is a case where two bypass ports 23A and 23B are installed close to each other so that each port is fully opened in the range W from the mesh start position (θs) to the mesh end position (θs + π). belongs to.
(D) is the number of bypass ports 23A, 23B that are fully opened in the range W from the meshing start position (θs) to the meshing end position (θs + π) of the stepped portions 13D, 13E, 14D, 14E, or the opening area per one. And the total opening area is approximately twice the total opening area of the second bypass ports 25A and 25B and the third bypass ports 26A and 26B provided in the other ranges W2 and W3.

In any case of the above embodiment, the same effect as that of the first embodiment described above can be expected.
Further, as shown in FIGS. 6 and 9A, in addition to the bypass ports 23A and 23B, positions where the step portions 13D, 13E, 14D, and 14E start meshing from the suction closing position (θd) of the compression chamber 15 ( By providing at least one second bypass port 25A, 25B that is opened in a range W2 up to θs) and opened when the pressure in the compression chamber 15 is overcompressed to a set pressure or higher, Stepped portions 13D, 13E, 14D from the engagement on the outer peripheral side than the stepped portions 13D, 13E, 14D, 14E where the heights of the spiral wraps 13B, 14B are increased, that is, from the suction cutoff position (θd) of the compression chamber 15 , 14E in the meshing in the range W2 up to the position (θs) at which meshing starts (θs), the pressure in the compression chamber 15 increases due to over-compression or liquid compression and exceeds the set pressure. When Tsu, by opening the second bypass port 25A, the 25B, it is possible to relief the compressed gas in the compression chamber 15 to the discharge chamber 21.

  As a result, the strength of the spiral wraps 13B and 14B is sufficiently ensured even on the outer peripheral side of the step portions 13D, 13E, 14D and 14E where the strength is weakened by increasing the wrap height of the spiral wraps 13B and 14B. , Durability and reliability can be ensured. At the same time, power loss due to overcompression can be reduced.

  Further, as shown in FIGS. 6 and 9B, in addition to the bypass ports 23A and 23B and the second bypass ports 25A and 25B, positions where the step portions 13D, 13E, 14D, and 14E have finished meshing (θs + π) To the position (θp) where the pair of compression chambers 15 join and communicate with the discharge port 13C, and is opened when the pressure in the compression chamber 15 is overcompressed to a set pressure or higher. By providing at least one bypass port 26A, 26B, a position where the compression chamber 15 communicates with the discharge port 13C from the position (θs + π) where the meshing at the step portions 13D, 13E, 14D, 14E is completed. Even in meshing in the range W3 up to (θp), when the pressure in the compression chamber 15 increases due to over-compression or liquid compression and becomes equal to or higher than the set pressure, the third bypass position is reached. By opening bets 26A, the 26B, it is possible to relief the compressed gas in the compression chamber 15 to the discharge chamber 21.

  For this reason, in the entire compression stroke including the range in which the pressure in the compression chamber 15 rises most due to overcompression or liquid compression, the compressed gas whose pressure is abnormally increased is surely relieved to the discharge chamber 21 to overcompress and liquid. Compression can be prevented, durability and reliability can be ensured, and power loss due to overcompression can be reduced.

  Further, as shown in FIGS. 6, 7 and 9D, in the range W from the position (θs) where the step portions 13D, 13E, 14D and 14E start to engage to the position (θs + π) where the engagement ends. The number of bypass ports 23A and 23B to be opened is increased or the area is increased so that the total opening area of the second bypass ports 25A and 25B or the third bypass ports 26A and 26B opened in the other ranges W2 and W3. When the total opening area of the bypass ports 23A and 23B opened in the range W in which the stepped portions 13D, 13E, 14D, and 14E mesh with each other is made larger than the opening area, and overcompression or liquid compression occurs, The refrigerant gas in the compression chamber 15 whose pressure has abnormally increased is quickly relieved to the discharge chamber 21, and the steps 13D, 13E, 14 , It is possible to more reliably prevent the occurrence of over-compression and the liquid compression in the interval W of 14E meshes.

  As a result, stress concentration due to over-compression or liquid compression on the root portions of the tooth tip surface side step portions 13D and 14D of the spiral wraps 13B and 14B can be avoided more reliably, and the durability and reliability of the stepped scroll compressor 1 can be avoided. Can be further improved. Furthermore, while the diameter of this type of bypass port is limited to a predetermined diameter or less, the total opening area can be easily increased by increasing the number of bypass ports 23A and 23B or increasing the area per one. it can. Therefore, the total opening area of the bypass ports 23A and 23B provided in the section W in which the step portions 13D, 13E, 14D, and 14E mesh with each other is increased, and overcompression and liquid in the section W in which the step portions 13D, 13E, 14D, and 14E mesh with each other. Compression can be prevented more reliably.

  Further, the bypass ports 23A and 23B, the second bypass ports 25A and 25B, and the third bypass ports 26A and 26B are provided with reed valves 24, 27, and 28 that are opened at a set pressure or higher, respectively. For this reason, the pressure in the compression chamber 15 rises by over-compression or liquid compression at the position where each bypass port 23A, 23B, 25A, 25B, 26A, 26B is provided, and the pressure is increased to each bypass port 23A, 23B, When the pressure exceeds the set pressure of the reed valves 24, 27, 28 provided in 25A, 25B, 26A, 26B, the respective reed valves 24, 27, 28 are opened, and the bypass ports 23A, 23B, 25A, 25B, 26A are opened. , 26B can be opened to the discharge chamber 21. Therefore, the bypass valves 23A, 23B, 25A, 25B, 26A, 26B can be easily opened above the set pressure by the respective reed valves 24, 27, 28. The compressed gas can be relieved to the discharge chamber 21.

  When two or more of the bypass ports 23A and 23B, the second bypass ports 25A and 25B, and the third bypass ports 26A and 26B are respectively provided, the plurality of ports are installed close to each other. Since the common reed valves 24, 27, and 28 can be opened and closed, usually, when the number of bypass ports is increased, the number of reed valves needs to be increased accordingly. The number of reed valves 24, 27, and 28 can be halved with respect to the number of bypass ports. Therefore, the installation of the reed valves 24, 27, and 28 in a narrow space can be facilitated, and the function of preventing overcompression and liquid compression can be improved by increasing the number of bypass ports.

  In addition, this invention is not limited to the invention concerning the said embodiment, In the range which does not deviate from the summary, it can change suitably. For example, in the said embodiment, it is set as the stepped scroll compressor 1 which each provided step part 13D, 13E and 14D, 14E in the predetermined position along the spiral direction of the tooth tip surface and tooth bottom surface of spiral wrap 13B, 14B. However, each of the step portions 13D, 13E and 14D, 14E may be configured by a plurality of steps (for example, each step portion is configured by two steps) (FIGS. 2, 6, and 7 include The two steps are shown in each case).

  In this way, by configuring each stepped portion 13D, 13E and 14D, 14E with a plurality of steps, the stress acting on the root of the stepped portion 13D, 14D on the tooth tip surface side can be dispersed, so that the spiral wrap 13B, 14B can improve the strength of the bypass port and is provided so as to open in a range W from the position (θs) at which the step portions 13D, 13E, 14D, and 14E start meshing to the position (θs + π) at which meshing ends. The durability and reliability of the stepped scroll compressor 1 against overcompression and liquid compression can be further improved by a synergistic effect with the effects of preventing overcompression and liquid compression by 23A and 23B.

  Further, in this case, the bypass ports 23A and 23B are arranged such that the first stage of the plurality of stages 13D and 13E and 14D and 14E, each having a plurality of stages, starts from the position (θs) where the first stage starts to mesh. Is provided so as to be opened in a range up to a position (θs + π) where the meshing ends, and the first stage of the plurality of stages of the respective step portions 13D, 13E, 14D, 14E starts from the position (θs) where the meshing starts. When the pressure in the compression chamber 15 increases due to over-compression or liquid compression within the range up to the position (θs + π) where the engagement ends, the bypass port 23A, 23B is opened, and the compressed gas in the compression chamber 15 is relieved to the discharge chamber 21.

Furthermore, in the above-described embodiment, an example in which one end portion of the crankshaft 5 is protruded outward of the housing 2 and applied to the scroll compressor 1 driven by power from the outside has been described. Needless to say, the present invention can be similarly applied to a hermetic type electric scroll compressor that is integrated with an electric motor and is driven by the electric motor.
Further, as shown in FIG. 8, the reed valves 24, 28 may be constituted by a single reed valve configured in a bifurcated shape, thereby further reducing the number of reed valves and simplifying the structure. And facilitating assembly.

DESCRIPTION OF SYMBOLS 1 Scroll compressor 13 Fixed scroll 13B, 14B Spiral wrap 13C Discharge port 13D, 13E, 14D, 14E Step part 14 Orbiting scroll 15 Compression chamber 23A, 23B Bypass port 24, 27, 28 Reed valve 25A, 25B 2nd bypass port 26A, 26B Third bypass port θs Position at which stepped portion starts meshing θs + π Position at which stepped portion ends meshing θd Suction cut-off position θp of compression chamber Position at which compression chamber communicates with discharge port

Claims (13)

Step portions are provided at positions along the spiral direction of the tooth tip surface and the tooth bottom surface of the spiral wrap of the fixed scroll and the orbiting scroll, and the wrap height on the outer peripheral side of the spiral wrap is the inner periphery with the step portion as a boundary. In a scroll compressor that is higher than the wrap height on the side,
Wherein the bottom land of the fixed scroll, an opening in a range up to the position where to end the engagement from a position ([theta] s) to initiate at least the stepped portion is engaged (θs + π), the pressure in the compression chamber is excessively compressed in the set pressure bypass port is opened when it is is provided at least one,
In addition to the bypass port, an opening is made in the range from the position (θs + π) where the stepped portion has finished meshing to the position (θp) where the compression chamber communicates with the discharge port, and the pressure in the compression chamber is equal to or higher than a set pressure. A scroll compressor characterized in that at least one third bypass port that is opened when it is overcompressed is provided .   In addition to the bypass port, an opening is made in the range from the suction closing position (θd) of the compression chamber to the position (θs) where the stepped portion starts to engage, and the pressure in the compression chamber is overcompressed to a set pressure or higher. 2. The scroll compressor according to claim 1, wherein at least one second bypass port that is opened when the scroll compressor is provided. The total opening area of the bypass port being open at the range to the position ([theta] s + [pi) to terminate the engagement from a position ([theta] s) of the stepped portion starts meshing, the third bypass that is opened at the other range The scroll compressor according to claim 1 , wherein the scroll compressor is larger than an opening area of the port. The second bypass in which the total opening area of the bypass port opened in a range from a position (θs) at which the step portion starts meshing to a position (θs + π) at which meshing ends is opened in another range. port or scroll compressor according to claim 2, characterized in that it is larger than the opening area of said third bypass port. The number of ports of the bypass ports, by being more than before number system ports of the third bypass port, the scroll compressor according to claim 3, characterized in that the total opening area is large. The number of ports of the bypass ports, said by being more than the number of ports of the second bypass port or said third bypass port, scroll according to claim 4, characterized in that the total opening area is larger Compressor. The port area per one bypass port, by prior SL is larger than the port area of 1 per third bypass port, it to claim 3, characterized in that the larger total opening area The scroll compressor described. And wherein the port area per one bypass port, by being larger than the port area of one per second bypass port or said third bypass port, the total opening area is larger The scroll compressor according to claim 4. Wherein the bypass port Contact and the third bypass port, claim 1, wherein a reed valve, each being open at set pressure is provided, according to claim 3, claim 5 or claim 7 The scroll compressor in any one. Said bypass port, wherein the second bypass port and said third bypass port, claim 2, characterized in that the reed valve is provided, each being open at set pressure, according to claim 4, claim 6 or The scroll compressor according to claim 8 . The reed valve, when said one bypass port Contact and said third bypass port is provided a plurality of each of two or more, by placing in close proximity to the plurality of ports to each other, one common reed valve The scroll compressor according to claim 9 , wherein the scroll compressor can be opened and closed. In the case where two or more of each of the bypass port, the second bypass port, and the third bypass port are provided, the reed valve is provided by arranging the plurality of ports close to each other. The scroll compressor according to claim 10 , which can be opened and closed by a common reed valve. Each of the steps is composed of a plurality of steps, and the bypass port extends from a position (θs) at which the first stage of the plurality of stages starts to mesh to a position (θs + π) at which the last stage finishes meshing. The scroll compressor according to any one of claims 1 to 12 , wherein the scroll compressor is provided so as to be opened in a range of.

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