JP5786130B2 - Scroll compressor - Google Patents

Description

  The present invention relates to a scroll compressor used in a cooling device such as a cooling / heating air conditioner or a refrigerator, or a heat pump type hot water supply device.

  2. Description of the Related Art Conventionally, scroll compressors used in refrigeration air conditioners and refrigerators generally form a compression chamber between the fixed scroll and the orbiting scroll in which the spiral wrap rises from the end plate to form a compression chamber therebetween, and the orbiting scroll is rotated by a rotation restraint mechanism. When it is swung along a circular orbit under the constraint of the above, suction, compression, and discharge are performed by moving the compression chamber while changing the volume. The working fluid is gradually compressed with the turning motion of the orbiting scroll, and becomes a high pressure state toward the center portion. Therefore, a separation force acts on the orbiting scroll in a direction away from the fixed scroll. As a result, a gap is generated between the orbiting scroll and the fixed scroll, so that leakage occurs during compression, resulting in performance deterioration. As a countermeasure, there is a method in which an intermediate pressure is applied to the back of the orbiting scroll to prevent separation from the fixed scroll (see, for example, Patent Document 1).

  In the scroll compressor described in Patent Document 1, the back pressure is obtained by the opening end of the communication hole that communicates with the back pressure chamber by the orbiting motion of the orbiting scroll provided on the end plate of the orbiting scroll and the orbiting scroll. The pressure in the back pressure chamber is maintained at a predetermined pressure, that is, an intermediate pressure, by a hole communicating the chamber and the compression chamber.

JP 2009-281377 A

  In the conventional configuration, there is no disclosure regarding the presence or absence of a bypass discharge hole for refrigerant gas, the timing of bypass discharge, and the timing of communication between the communication hole communicating with the back surface of the orbiting scroll and the back pressure chamber. Therefore, it is considered that the pressure in the compression chamber is increased by the overcompression operation during the low compression ratio operation. The back pressure chamber also has pressure pulsation, but it is necessary to set the back pressure as a necessary pressure to prevent the orbiting scroll from separating. A problem is likely to occur.

  The present invention solves the above-mentioned conventional problems, and by adjusting the timing at which the high pressure region and the back pressure chamber communicate with each other and the timing at which the bypass hole on the high volume ratio side opens, the pressure pulsation in the back pressure chamber is increased. By making the pressure in the compression chamber into an overcompressed state at the timing, it is not necessary to apply an excessive back pressure, and a scroll compressor that realizes high efficiency can be provided.

In order to solve the above-described conventional problems, a scroll compressor according to the present invention is configured such that a compression scroll is formed between both the fixed scroll and the orbiting scroll in which the spiral wrap rises from the end plate, and the back of the orbiting scroll is formed. Forms a high pressure region and a back pressure chamber, and the orbiting scroll revolves with a predetermined orbiting radius along a circular orbit by regulation by a rotation restraining mechanism, so that the compression chamber moves toward the center while changing its volume. In the scroll compressor that performs a series of operations of suction, compression, and discharge, the fixed scroll has a bypass discharge hole that communicates in the middle of compression in addition to the main discharge, and intermittently connects the high pressure region and the back pressure chamber. The timing at which the communication path is opened is 10 to 80 degrees earlier than the timing at which the bypass discharge hole is opened. It is set to be.

  In the scroll compressor according to the present invention, the opening end of the path connecting the high pressure region and the back pressure chamber opens to the back pressure side in the range of the crank angle of 10 to 80 ° before the bypass hole starts to open. Since the pressure of the back pressure chamber can be set high at the timing when the internal pressure of the compression chamber rises, it is possible to suppress the separation of the orbiting scroll without applying excessive pressure, and a scroll compressor that realizes high efficiency Can be provided.

Sectional drawing of the scroll compressor in Embodiment 1 of this invention The principal part expanded sectional view of the compression mechanism part of the scroll compressor in Embodiment 1 of this invention Sectional drawing in the state which meshed the fixed scroll and turning scroll of the scroll compressor in Embodiment 1 of this invention The graph which showed the pressure change in the compression chamber by the crank angle change of the scroll compressor in Embodiment 1 of this invention, and the pressure change in a back pressure chamber Sectional view of the conventional scroll compressor with the fixed scroll and the orbiting scroll engaged Graph showing the pressure in the compression chamber and the pressure in the back pressure chamber due to the crank angle change of the conventional scroll compressor

  The scroll compressor according to the first aspect of the present invention engages the fixed scroll and the orbiting scroll where the spiral wrap rises from the end plate to form a compression chamber therebetween, and a high pressure region and a back pressure chamber are formed on the back of the orbiting scroll. By forming and turning the orbiting scroll with a predetermined orbiting radius along the circular orbit by regulation by the rotation restraining mechanism, the compression chamber moves toward the center while changing the volume, and a series of operations of suction, compression and discharge In the scroll compressor that performs the above, the fixed scroll has a bypass discharge hole that communicates in the middle of compression separately from the main discharge, and the timing at which the path that intermittently communicates the high pressure region and the back pressure chamber is opened. , So that the crank angle opens 10 degrees or more and 80 degrees or less earlier than the timing when the bypass discharge hole of the compression chamber on the high volume ratio side opens. It is constant. As a result, the pressure of the back pressure chamber can be set high at the timing when the internal pressure of the compression chamber rises due to overcompression, so that it is possible to suppress the separation of the orbiting scroll without applying excessive pressure, realizing high efficiency. can do.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a longitudinal sectional view of a scroll compressor according to the first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of a main part of the compression mechanism unit according to the present embodiment. Hereinafter, the operation and action of the scroll compressor of this embodiment will be described.

As shown in FIGS. 1 and 2, the scroll compressor of the present invention includes a main bearing member 11 of a crankshaft 4 fixed by welding or shrink fitting in a sealed container 1, and a bolt on the main bearing member 11. The scroll-type compression mechanism 2 is configured by sandwiching the orbiting scroll 13 meshing with the fixed scroll 12 between the fixed scroll 12 and the rotation of the orbiting scroll 13 between the orbiting scroll 13 and the main bearing member 11. Then, a rotation restraint mechanism 14 such as an Oldham ring that guides the circular scroll to move is provided, and the orbiting scroll 13 is eccentrically driven by the eccentric shaft portion 4 a at the upper end of the crankshaft 4, whereby the orbiting scroll 13 is circularly orbited. As a result, the compression chamber 15 formed between the fixed scroll 12 and the orbiting scroll 13 moves from the outer peripheral side to the center portion. Utilizing this, the refrigerant gas is sucked and compressed from the suction pipe 16 leading to the outside of the sealed container 1 and the suction port 17 on the outer peripheral portion of the fixed scroll 12, and the refrigerant gas having a predetermined pressure or higher is compressed. The reed valve 19 is repeatedly pushed and discharged from the discharge port 18 at the center of the fixed scroll 12 to be discharged into the sealed container 1, and during low load operation, from the bypass hole 18 a provided in the middle of the compression chamber of the fixed scroll 12. The reed valve 19 is pushed open and discharged into the sealed container 1.

  In addition, a high pressure region 30 and a back pressure chamber 29 set to a high pressure and a low pressure are formed on the back surface 13e of the orbiting scroll 13. By applying pressure on the back surface 13e, the orbiting scroll 13 is stably pressed against the fixed scroll 12, and leakage can be reduced and the circular orbit motion can be stably performed.

  During operation of the compressor, a pump 25 is provided at the lower end of the crankshaft 4 and is driven simultaneously with the scroll compressor. As a result, the pump 25 sucks up the oil 6 in the oil reservoir 20 provided at the bottom of the hermetic container 1 and removes foreign matter with an oil filter or the like, and then passes through the oil supply hole 26 running vertically through the crankshaft 4. Supply to the compression mechanism 2. The supply pressure at this time is substantially equal to the discharge pressure of the scroll compressor, and also serves as a back pressure source for the orbiting scroll 13. As a result, the orbiting scroll 13 does not move away from the fixed scroll 12 and does not come into contact with each other, and the predetermined compression function is stably exhibited.

  A part of the oil 6 supplied in this way is obtained by a supply pressure or its own weight so as to obtain a clearance, between the fitting portion between the eccentric shaft portion 4a and the orbiting scroll 13, and between the crankshaft 4 and the main bearing member 11. Then, the oil enters the bearing portion 66, lubricates the respective portions, falls, and returns to the oil sump 20. Another part of the oil 6 supplied to the high pressure region 30 is formed in the orbiting scroll 13 and passes through the first path 54 having one open end in the high pressure region 30, and the rotation restraint mechanism 14 is located. The back pressure chamber 29 is entered, and the thrust sliding portion and the sliding portion of the rotation restraining mechanism 14 are lubricated, and the back pressure of the orbiting scroll 13 is applied in the back pressure chamber 29.

  In the orbiting scroll 13, a second path 55 having one open end 55 a is formed in the back pressure chamber 29, and the back pressure chamber 29 and the compression chamber 15 are intermittently associated with the orbiting motion of the orbiting scroll 13. Communicate. For example, in the case of the configuration shown in FIG. 2, intermittent communication is realized by periodically opening the other opening end 55 b in the second path 55 in the recess 12 d formed on the bottom surface of the wrap groove of the fixed scroll 12. Yes. As a result, oil is supplied to the compression chamber 15.

  Here, the amount of oil in the back pressure chamber 29 will be described. Regarding the oil 6 entering the back pressure chamber 29 from the high pressure region 30 via the first path 54 and the oil 6 entering the compression chamber 15 from the back pressure chamber 29 via the second path 55, the former When the amount of oil is large, the excess pressure of the oil 6 is supplied to the back pressure chamber 29, so that the pressure increases. As a result, excessive back pressure is applied to the orbiting scroll 13. If excessive back pressure is applied, the thrust load increases, causing problems such as performance deterioration and reliability deterioration. When the former oil amount is small, the back pressure is the reaction force of the internal pressure of the compression chamber. The smaller size causes problems such as performance deterioration and noise increase due to separation of the orbiting scroll.

FIG. 5 shows the relationship among the conventional orbiting scroll 13, fixed scroll 12 and opening end 54b when the bypass hole 18a is opened. As is apparent from FIG. 5, when the bypass hole 18a is opened, the opening end 54b is on the high pressure region side, so that no oil is supplied to the back pressure chamber 29.

  FIG. 6 is a graph showing a pressure change in the compression chamber 15 and a pressure change in the back pressure chamber 29 accompanying a change in crank angle during low load operation. The horizontal axis represents the crank angle, and the vertical axis represents the pressure change. Since the pressure in the compression chamber 15 often reaches the system high pressure before the opening end 54b is opened during the low load operation, the state becomes an overcompression operation as shown in the graph. At that time, the pressure in the compression chamber 15 increases and the reaction force to the orbiting scroll 13 increases. However, when the opening end 54b is opened, the pressure in the back pressure chamber 29 is not opened in the back pressure side region but is in the high pressure side region, so that the back pressure is low as shown in FIG.

  Therefore, it is necessary to set the required back pressure so that the orbiting scroll 13 does not separate from the fixed scroll 12 higher than the average back pressure. The back pressure is higher than the required pressure normally in a system such as a rated operation or during a heavy load operation. Since it becomes large, the sliding loss which arises between the turning scroll 13 and the fixed scroll 12 increases.

  Therefore, in the scroll compressor according to the present embodiment, the other opening end 54b formed on the back surface 13e of the orbiting scroll 13 is periodically moved between the high-pressure region 30 and the back pressure chamber 29, and the opening end 54b. Is set to 10 ° to 80 ° before the bypass hole 18a is opened. That is, as shown in FIG. 3, since the opening end 54b opens to the back pressure side, the high pressure oil flows into the back pressure chamber 29 from the opening end 54b. FIG. 4 shows a graph showing changes in pressure due to changes in the crank angle according to the present invention. As is apparent from the graph, the pressure in the back pressure chamber increases during an overcompression state in which the pressure in the compression chamber increases, and the required back pressure during low load operation can be set small. As a result, it is possible to provide a scroll compressor that achieves high efficiency by reducing the back pressure.

  As described above, the scroll compressor according to the present invention has the back pressure by opening the opening end 54b of the first path 54 into the back pressure chamber 29 10 to 80 degrees before the timing when the bypass hole 18a opens. The chamber pressure can be set low, and the present invention can be applied to applications of scroll fluid machines such as an air scroll compressor, a vacuum pump, and a scroll type expander without limiting the refrigerant.

DESCRIPTION OF SYMBOLS 1 Airtight container 2 Compression mechanism 6 Oil 12 Fixed scroll 12d Recessed part 13 Orbiting scroll 13e Back surface 14 Rotation restraint mechanism 15 Compression chamber 18a Bypass hole 26 Oil supply hole 29 Back pressure chamber 30 High pressure area | region 54 1st path | route 54b Open end (back pressure) Room side)
55 Second path 55a Open end (back pressure chamber side)
55b Open end (compression chamber side)

Claims (1)

A compression scroll is formed between the fixed scroll and the orbiting scroll where the spiral wrap rises from the end plate, and a high pressure region and a back pressure chamber are formed on the back of the orbiting scroll, and the above-mentioned restriction is imposed by a rotation restraint mechanism. In the scroll compressor in which the orbiting scroll revolves with a predetermined orbital radius along the circular orbit, the compression chamber moves toward the center while changing the volume, and performs a series of operations of suction, compression, and discharge.
The fixed scroll has a bypass discharge hole that communicates in the middle of compression separately from the main discharge, and the bypass discharge hole opens at a timing when a path that intermittently connects the high pressure region and the back pressure chamber opens. A scroll compressor that is set to open 10 to 80 degrees earlier than the timing at a crank angle.