JP2007023790A - Scroll compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate useless infiltration from an external part via a drain hole 60 while draining water inside of a compression space via the drain hole 60. <P>SOLUTION: The drain hole 60 connecting the compression space to the external part exists in a lower part of this scroll compressor. An opening-closing valve 70 exists near an opening of the drain hole 60. The opening-closing valve 70 is a valve with pressure of the compression space as control pressure. When operating the scroll compressor, the opening-closing valve 70 is closed, and when stopping the scroll compressor, the opening-closing valve 70 is opened. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a scroll compressor having a drain hole for draining water from a compression space, and more particularly to a technique suitable for an electric compressor that assists an engine-driven reciprocating compressor as a compressor mounted on a vehicle.

  In general, scroll compressors are smaller and less noise than engine driven reciprocating compressors. Therefore, for example, in a commercial vehicle, it is technically effective to dispose the scroll compressor outside the engine room in order to assist the engine-driven compressor in the engine room. Unlike the interior space of a closed engine room, the exterior of the engine room must be mindful of compressor installation (eg, location, space, etc.) and must deal with the effects of sound generation. In this respect, the small size and low noise characteristics of the scroll compressor are optimal characteristics as a compressor disposed outside the engine room.

  Therefore, the inventor conducted various experiments on the case where the scroll compressor is installed in the vehicle, particularly outside the engine room. As a result, I noticed the problem of water generated in the compression space. The compressor sucks outside air, that is, an atmosphere containing moisture, and converts it into compressed air. Therefore, when the compressor is stopped, the air in the compression space is cooled and moisture is dripped, and water accumulates in the compression space. Considering the environment in which the vehicle is used, it is conceivable that water that has entered the compression space freezes at night and adversely affects the compressor when the vehicle is started. In particular, since the scroll compressor partitions the compression space by the fixed scroll and the orbiting scroll that mesh with each other, there is a risk of damaging the scroll blade (scroll tip portion).

In order to solve the problem caused by such water, it is an effective measure to provide a drain hole and discharge the intruded water. As a result of investigating the prior art with regard to the water drain hole, Patent Document 1 was found that a water drain hole is provided in the vicinity of the discharge port and water is discharged through the hole. Although patent document 1 is a scroll type, it is not a compressor for obtaining compressed air but a vacuum pump. However, in the scroll type, the idea of providing a drain hole for discharging intruding water is clarified.
Japanese Patent No. 3388558

  Although the vacuum pump of Patent Document 1 shows that a drain hole is provided, when used as a scroll compressor for a vehicle, the compression space inside the scroll and the outside air always communicate with each other through the drain hole. There remains a problem that water or the like enters the scroll from the outside through the hole. In particular, in the case of a vehicle, cleaning water may enter during cleaning with high-pressure water, and muddy water or the like may enter during operation of the vehicle. As described above, the intrusion of foreign matter containing water or moisture may freeze the water in the compression space and cause the scroll member to be damaged or the compressor function to be impaired. Moreover, the drain hole which patent document 1 shows is for discharging | emitting the water droplet liquefied by the air compression, and is provided in the center vicinity of compression space. Therefore, moisture generated by cooling the air in the compression space when the compressor is stopped cannot be effectively discharged.

Accordingly, an object of the present invention is to provide a technique capable of discharging water inside the compression space through the drain hole and preventing unnecessary intrusion from the outside through the drain hole.
Another object of the present invention is to provide a technique in which the drain hole is blocked from the outside during the operation of the scroll compressor and the drain hole is opened to the outside when the scroll compressor is stopped.
Other objects of the present invention will become clear from the following description.

  This invention is based on the premise that a water drain hole communicating with the outside from the compression space is provided in order to discharge water inside the compression space. Under the premise, a specific on-off valve is provided near the opening of the drain hole. “Near the opening” means close to the opening that opens the drain hole to the outside in the passage of the drain hole. An on-off valve near the opening can discharge water reliably and quickly.

  The on-off valve is configured to be closed when the scroll compressor 10 is in operation and open when the scroll compressor 10 is stopped. For example, the on / off valve may be an electromagnetic control valve, and the opening / closing of the valve may be controlled in accordance with a control signal accompanying the operation / stop of the scroll compressor. However, it is preferable to utilize the fact that the compression space becomes a pressurized state / normal pressure (that is, atmospheric pressure) state according to the operation / stop of the scroll compressor, and the pressure in the compression space is used as the control pressure. It is good to open and close the valve. Then, the valve can be controlled to open and close with a simple piston structure or spool structure without using an electrical signal.

  The most preferred on-off valve includes a small-diameter portion and a large-diameter portion, and includes a piston that defines a pressure-receiving area corresponding to a difference in pressure-receiving areas of the large and small-diameter portions, and a valve spring that pushes the piston in the axial direction. It is. When the scroll compressor is in operation, the stepped piston receives the pressure of the compressed air in the compression space in a portion corresponding to the difference in the pressure receiving area of the large and small diameter portions, and the force based on the pressure overcomes the force of the valve spring. Close the on-off valve. On the other hand, when the scroll compressor is stopped, the pressure in the compression space becomes atmospheric pressure, so that the opening / closing valve is opened by the force of the valve spring, and the water inside the compression space is discharged outside through the opening / closing valve in the open state.

  Here, as the pressure received by the portion corresponding to the difference in pressure receiving area of the large and small diameter portions (stepped portions), an intermediate pressure between the suction port and the discharge port in the compressor may be appropriately selected and applied. it can. Accordingly, the spring constant of the valve spring can be determined. Further, the compressed air inside the compression space gradually increases the pressure from the suction port to the discharge port. Therefore, it is possible to adopt a form in which different pressures are applied to both ends of the piston or the spool by drawing out pressures from two different portions in the compression space.

  Further, since water descends in the compression space due to gravity, the drain hole is preferably disposed below the fixed scroll and the orbiting scroll with the scroll compressor installed.

  FIG. 1 is a diagram showing a cross-sectional structure of a scroll compressor 10 according to an embodiment of the present invention. With reference to FIG. 1, first, the overall structure of the scroll compressor 10 will be clarified, and then the features of the present invention will be referred to.

  The outer shell of the scroll compressor 10 includes a bowl-shaped first housing 101 and a dish-shaped second housing 102. The second housing 102 includes an outer ring part 102a and an inner disk part 102b of the ring part. The disk part 102 b is also a part constituting the end plate of the fixed scroll 20. Therefore, the inner surface of the disk portion 102b is flat, and the spiral fixing wrap 22 is on the flat surface. The fixed wrap 22 is integral with the disk portion 102b and stands upright with respect to a flat surface. And there exists a groove | channel in the front-end | tip of the fixed wrap 22, and the chip seal | sticker 24 has entered in it.

  The second housing 102 carrying such a fixed wrap 22 integrally is positioned integrally with the first housing 101 by mounting bolts (not shown) while being positioned by the positioning pins 103. The first housing 101 combined with the second housing 102 accommodates the orbiting scroll 30 in a space portion on the inner peripheral side thereof.

  The orbiting scroll 30 is integrally provided with a spiral orbiting wrap 32 on a flat surface. Similar to the fixed wrap 22, the orbiting wrap 32 also stands upright on a flat surface and holds a tip seal 34 at its tip. The radially outer portion of one flat surface of the orbiting scroll 30 reaches the ring portion 102a on the outer periphery of the second housing 102, and together with the seal member 104 held by the ring portion 102a, the inner periphery of the second housing 102 Seal the side space tightly. Moreover, the orbiting wrap 32 of the orbiting scroll 30 meshes with the fixed wrap 22 of the fixed scroll 20 to partition the compression space.

  The scroll compressor 10 produces compressed air by causing the orbiting scroll 30 to rotate without rotating, with respect to the fixed scroll 20 that always maintains a constant state. A mechanism for orbiting the orbiting scroll 30 without rotating is the crankshaft 40 at the center of the first housing 101 (the crankshaft 40 is rotationally driven by an electric motor (not shown)) and three locations around the crankshaft 40. The anti-rotation mechanism 50 (the anti-rotation mechanism 50 is constituted by a driven crankshaft or an Oldham joint).

  The scroll compressor 10 has a suction port 105 at the outer peripheral portion of the first housing 101 and a discharge port 107 at the center of the second housing 102. The atmosphere sucked from the suction port 105 in the outer peripheral portion enters the compression space surrounded by the fixed wrap 22 and the swirl wrap 32, and moves along the movement of the swirl wrap 32. The pressure is gradually increased. Compressed compressed air is supplied to an air tank through a pipe and an air dryer from a discharge port 107 at the center of the second housing 102, and is used, for example, for brake operation of a vehicle.

  The compressed air inside the air tank has moisture removed beforehand by an air dryer, but the air that enters the scroll compressor 10 from the suction port 105 contains moisture. Therefore, as described above, it is inevitable that water accumulates in the compression space surrounded by the fixed wrap 22 and the swirl wrap 32. Most of such water flows to the lower side of the scroll compressor 10 by the gravitational action as the swirl wrap 32 moves.

  In the present invention, in order to discharge such water to the outside, the drain hole 60 is provided in the lower part of the scroll compressor 10, and the opening / closing valve 70 is provided near the opening of the drain hole 60.

  FIG. 2 is an enlarged view of a portion indicated by reference numeral 2 in FIG. 1, (A) shows each state when the scroll compressor 10 is stopped, and (B) shows each state when the scroll compressor 10 is in operation. The drain hole 60 is located at the lowest position of the second housing 102, the inner end 601 faces the inner periphery of the ring portion 102a, and the outer end 602 faces the outside. The drainage hole 60 is a hole extending vertically, and has a plurality of stepped hole structures that gradually increase in diameter from the inner end 601 toward the outer end 602. That is, a first hole 61 having a small diameter on the inner end 601 side, a second hole 62 having a medium diameter adjacent to the first hole 61, a third hole 63 having a large diameter following the second hole 62, and a third hole This is the order of the fourth hole 64 having a diameter larger than that of the hole 63.

  In such a drain hole 60, there is an on-off valve 70 mainly composed of a stepped piston 72. The stepped piston 72 includes a small-diameter portion 721 and a large-diameter portion 722, and holds seal rings 721s and 722s on the outer circumferences of both portions. The stepped piston 72 has a small diameter portion 721 in the second hole 62 and a large diameter portion 722 in the third hole 63 to define a pressure receiving area corresponding to a difference in pressure receiving areas of the large and small diameter portions. is doing. One end of the control pressure passage 80 is opened at the step portion between the second hole 62 and the third hole 63 of the drain hole 60. The control pressure passage 80 is an internal passage provided inside the second housing 102, and the other end communicates with the inside of the compression space. The pressure in the compression space defined by the fixed scroll and the orbiting scroll gradually increases as it goes from the outer peripheral suction port 105 to the central discharge port 107. In this example, however, the pressure in the portion located approximately in the middle in the radial direction is reduced. The pressure (pressure lower than the pressure produced by the scroll compressor 10) is derived. The stepped piston 72 has a through hole 723 that passes through the center.

  Further, a valve seat member 74 is provided in a portion adjacent to the stepped piston 72 in the drain hole 60. The valve seat member 74 is positioned so as to extend from the third hole 63 to the fourth hole 64, and is supported between the stopper ring 75 and its own step 742. The valve seat member 74 has a ring-shaped valve seat 740 on the inner end surface, and a notch 743 for communicating one end on the inner side and the other end on the outer side on the side surface portion. Furthermore, there is a valve spring 76 between the valve seat member 74 and the stepped piston 72. The valve spring 76 pushes the stepped piston 72 to the inside of the drain hole 60 when the scroll compressor 10 stops (that is, when the pressure of the pressure passage 80 is atmospheric pressure), and the stepped piston 72 is pushed to the valve seat member 74. The spring force is sufficient to move away from the valve seat 740. However, the spring force of the valve spring 76 is set to a value smaller than the force based on the pressure when the pressure of the control pressure passage 80 communicating with the pressure space increases as the scroll compressor 10 operates. With such setting, the on-off valve 70 can be controlled to be closed / open according to the operation / stop of the scroll compressor 10. When the scroll compressor 10 is stopped, the water inside the pressure space is in the drain hole 60, the first hole 61, the through hole 723 of the stepped piston 72, and the notch 743 and the fourth hole of the valve seat member 74. 64 is discharged to the outside.

1 is a cross-sectional structure diagram showing an embodiment of the present invention. It is a figure which expands and shows the part shown with the code | symbol 2 of FIG. 1, (A) shows each state at the time of a driving | operation at the time of a stop.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Scroll compressor 20 Fixed scroll 30 Orbiting scroll 40 Crankshaft 50 Rotation prevention mechanism 60 Water drain hole 70 On-off valve 72 Piston (piston with step)
74 Valve seat member 76 Valve spring 80 Control pressure passage 105 Suction port 107 Discharge port

Claims (5)

  A fixed scroll, a orbiting scroll that meshes with the fixed scroll and defines a compression space, and a mechanism that causes the orbiting scroll to rotate without rotating, and sucks outside air from the outer peripheral side of the fixed scroll and the orbiting scroll, A scroll compressor for discharging compressed air from the center of a scroll, comprising: a drain hole communicating from the inside of the compression space to the outside; and an on-off valve provided near the opening of the drain hole, the on-off valve being a scroll A scroll compressor configured to be closed when the compressor is in operation and open when the compressor is stopped.   The on-off valve uses the fact that the compression space is in a pressurized state / normal pressure state according to the operation / stop of the scroll compressor, and opens and closes the valve using the pressure in the compression space as a control pressure. The scroll compressor according to claim 1.   The on-off valve includes a small-diameter portion and a large-diameter portion, and includes a piston that defines a pressure-receiving area corresponding to a difference in pressure-receiving areas of the large and small-diameter portions, and a valve spring that pushes the piston in the axial direction, During operation of the scroll compressor, the piston receives the pressure in the compression space in a portion corresponding to the difference in the pressure receiving area of the large and small diameter portions, overcomes the force based on the pressure, and closes the on-off valve. The scroll compressor according to claim 2, wherein when the scroll compressor is stopped, the on-off valve is opened by the force of the valve spring.   The scroll compressor according to claim 2, wherein the pressure is an intermediate pressure between a suction port that sucks in the outside air and a discharge port that discharges the compressed air.   2. The scroll compressor according to claim 1, wherein the drain hole is positioned below both the fixed and swivel scrolls in a state where the scroll compressor is installed.

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