JP2008215115A - Scroll compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a serious problem of equipment on which a scroll compressor is mounted, which is caused when the opening degree of a back pressure control valve is minute because foreign matters existing in lubricating oil are apt to be jammed in the back pressure control valve and a back pressure control mechanism does not function, so that there occurs malfunction of the compressor, under such circumstances that operating stability of the scroll compressor under a lower differential pressure condition is required in response to a recent demand for high efficiency, while it is necessary to improve adhesion between a fixed scroll and a turning scroll by increasing a differential pressure of a back pressure chamber, and therefore, it is necessary to increase the spring constant of a spring for control in the back pressure control mechanism formed in the fixed scroll. <P>SOLUTION: A conical needle valve is employed for the back pressure control valve of the back pressure control mechanism so as to improve sealing performance and increase pressure loss, thereby ensuring a sufficient clearance of the back pressure control valve and avoiding the jamming of foreign matters. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a compressor used in an air conditioner, a refrigeration apparatus, etc., and when a back pressure control mechanism is provided, the back pressure control valve A scroll compressor that can improve the reliability by avoiding the biting of dust is provided.

  As a conventional scroll compressor, an arcuate compression chamber is formed by meshing a fixed scroll having a spiral scroll lap formed upright on an end plate and a turning scroll to form an arcuate compression chamber, and the rotating scroll is restrained from rotating with respect to the fixed scroll. In some cases, the compression operation is performed by reducing the volume while moving the compression chamber from the outer peripheral side toward the inner periphery by swirling in a state. This scroll compressor has a problem that the compressed gas leaks from the meshing portion of the orbiting scroll and the fixed scroll and causes a reduction in efficiency, and various countermeasures have been proposed conventionally (for example, Patent Document 1).

FIG. 6 is a sectional view of a conventional hermetic scroll compressor described in Patent Document 1, and FIG. 7 is an enlarged sectional view of the back pressure control mechanism. In the figure, 3 is a fixed scroll, 4 is a turning scroll, 30 is a back pressure control mechanism provided in the fixed scroll, and the control spring 41 operates so that the back pressure chamber 10 is maintained at a certain pressure difference or more. Then, the back pressure control valve 40 is lifted to form a minute fluid path, and the pressure is controlled by the flow of the compressor lubricating oil in the back pressure chamber 10, so that a gap between the fixed scroll 3 and the orbiting scroll 4 is formed. To reduce leakage loss.
JP 2002-310076 A (pages 2 to 3, FIG. 1)

  However, in response to demands for higher efficiency in recent years, scroll compressors are required to operate stably in a lower differential pressure state, and the adhesion between the fixed scroll and the orbiting scroll is improved by increasing the differential pressure in the back pressure chamber. Therefore, it is necessary to increase the spring constant of the control spring in the back pressure control mechanism formed on the fixed scroll, but if the back pressure control valve opening is too small, the back pressure control valve should be lubricated. It becomes easy to chew the dust present in the oil, causing a problem that the back pressure control mechanism does not function. As a result, the compressor malfunctions, causing a big problem in the equipment to be mounted.

  The present invention solves the above-mentioned conventional problems, and a scroll compressor that can improve reliability by avoiding back-pressure control valve dust biting by sufficiently securing a gap of the back-pressure control valve. The purpose is to provide.

  In order to solve the above-described conventional problems, the scroll compressor of the present invention uses a conical needle valve as the back pressure control valve of the back pressure control mechanism, and sufficiently increases the pressure loss so that the gap of the back pressure control valve is sufficiently increased. It secures and avoids the bite of dust.

  This configuration increases the pressure loss even when the back pressure control mechanism has a stepped taper, or when the back pressure control mechanism has the same taper angle as the back pressure control valve. It is possible to ensure a sufficient gap between the back pressure control valves and avoid the biting of dust.

The scroll compressor of the present invention can provide a scroll compressor that can ensure high efficiency even at a low differential pressure by reliable back pressure control while ensuring the reliability of the back pressure control mechanism.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a sectional view of a scroll type hermetic compressor according to an embodiment of the present invention, and FIG. 2 is an enlarged view of the back pressure control mechanism 12 in FIG. In FIG. 1, 4 is a turning scroll, and 3 is a fixed scroll, which are engaged to form a compression chamber 11. 6 is a suction hole for sucking the refrigerant, 7 is a discharge hole for discharging the compressed refrigerant, 5 is an Oldham joint that restrains the rotation of the orbiting scroll 4, and the swivel is driven by the rotation of the rotating shaft 2 driven by the electric motor 1. Compression is performed by the scroll 4 turning. Reference numeral 12 denotes a back pressure control mechanism provided on the fixed scroll 3, which includes a back pressure control valve 13, a control spring 14, and a back pressure pin 15, and a back pressure chamber 10 provided on the back of the orbiting scroll 4. The oil pump 8 connected to the lower end of the rotating shaft 2 supplies the lubricating oil 9 to the back pressure chamber 10 through the space inside the rotating shaft 2, and when the pressure reaches a certain level or more, the control pump The spring 14 is actuated to open the back pressure control valve 13 and communicate with the compression chamber 11. Thereby, the pressure of the back pressure chamber 10 is kept constant.

  In FIG. 2, the back pressure control valve 13 is a conical needle valve, and the back pressure control valve 13 forms a minute gap W so that the lubricating oil 9 is compressed from the back pressure chamber 10 to the compression chamber 11 as shown by the arrow in the figure. Flow into. By making the back pressure control mechanism part back pressure control valve 13 into a conical needle valve, the sealing performance is improved, the leakage is reduced from the seal part and the pressure loss is increased, so that W is sufficiently secured, and the lubricating oil is made dust. Even in the case where there is, reliability is improved by avoiding biting of dust.

(Embodiment 2)
FIG. 3 is a schematic diagram of the back pressure control mechanism part according to the second embodiment of the present invention. The taper part of the back pressure control mechanism part has a stepped shape to increase the pressure loss, thereby ensuring sufficient W, so that the lubricating oil can be used. Even if dust is present, reliability is improved by avoiding biting of dust.

(Embodiment 3)
FIG. 4 is a schematic diagram of the back pressure control mechanism unit according to the third embodiment of the present invention. The taper angle of the back pressure control mechanism unit is the same as that of the back pressure control valve, and W is sufficiently increased by increasing the pressure loss. The reliability is improved by avoiding biting of dust even when dust is present in the lubricating oil.

(Embodiment 4)
FIG. 5 is a schematic diagram of the back pressure control mechanism in Embodiment 4 of the present invention. The gap between the side surface of the back pressure control valve and the cylindrical space is reduced, and sufficient pressure loss is ensured to sufficiently secure W and lubricate. Even when dust is present in the oil, reliability is improved by avoiding biting of dust.

  As described above, the scroll compressor according to the present invention can sufficiently open the back pressure control valve regardless of the operating conditions, so that it does not cause malfunction of the back pressure control mechanism due to foreign matter biting, and always. Since a stable back pressure can be maintained, it can be widely applied to heat pump application devices such as a dehumidifier and a water heater in addition to a refrigerating device such as an air conditioner and a refrigerator.

Sectional drawing of the compressor in Embodiment 1 of this invention The expanded sectional view at the time of the action | operation of the back pressure control mechanism part in Embodiment 1 of this invention The expanded sectional view of the back pressure control mechanism part in Embodiment 2 of this invention The expanded sectional view of the back pressure control mechanism part in Embodiment 3 of this invention The expanded sectional view of the back pressure control mechanism part in Embodiment 4 of this invention Sectional view of a compressor in a conventional example Expanded cross-sectional view of back pressure control unit in conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric motor 2 Rotating shaft 3 Fixed scroll 4 Orbiting scroll 5 Oldham coupling 6 Suction hole 7 Discharge hole 8 Oil pump 9 Lubricating oil 10 Back pressure chamber 11 Compression chamber 12 Back pressure control mechanism 13 Back pressure control valve 14 Control spring 15 Back Pressure pin

Claims (4)

A compression chamber is formed by meshing a fixed scroll and an orbiting scroll in which spiral scroll wraps are formed upright on each end plate, and a predetermined pressure is maintained on the anti-scroll wrap side of the orbiting scroll by a back pressure control mechanism. And the revolving scroll is urged toward the fixed scroll side by the pressure from the back pressure chamber to prevent the separation from the fixed scroll. A scroll compressor that performs compression operation while reducing the volume while moving from the outer peripheral side toward the center, wherein the back pressure control mechanism is directed to the back pressure chamber through a passage that connects the back pressure chamber and the outer peripheral side compression chamber. A cylindrical space having an opening hole that opens and a tapered processing portion provided at an outer edge of the opening hole, and the opening hole is disposed in the cylindrical space so that the opening hole can be closed and opened. A back pressure control valve and a control spring that biases the back pressure control valve toward the opening hole are housed, and the control spring has a constant pressure difference between the back pressure chamber pressure and the outer compression chamber pressure. The strength of the back pressure control valve is adjusted so that the back pressure control valve is separated from the opening hole only when the value is exceeded, and the back pressure control valve has a conical needle valve with a portion that closes the opening hole. Is a scroll compressor. 2. The scroll compressor according to claim 1, wherein the back pressure control valve is formed by stepping a tapered portion of the back pressure control mechanism to reduce a gap on a side surface of the back pressure control valve to increase pressure loss. A scroll compressor characterized in that a sufficient gap is secured. 2. The scroll compressor according to claim 1, wherein a taper angle of a taper processing portion of the back pressure control mechanism portion is set to the same angle as the back pressure control valve to reduce a gap on a side surface of the back pressure control valve to reduce pressure loss. A scroll compressor characterized by ensuring a sufficient clearance between the back pressure control valves by increasing the number. 2. The scroll compressor according to claim 1, wherein the back pressure control valve has a sufficient clearance by reducing the diameter of the back pressure control mechanism to reduce the gap on the side surface of the back pressure control valve and increase the pressure loss. A scroll compressor characterized by being secured.

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