SCROLL COMPRESSOR

This application is a U.S. national stage application of PCT/JP2014/002017 filed on Apr. 9, 2014, the contents of which are incorporated herein by reference.

The present invention relates to a scroll compressor that is primarily mounted on a refrigerant circuit of a refrigerator, an air-conditioning apparatus, a water heater, or other devices.

As an existing scroll compressor, a scroll compressor in which, when the material of an orbiting scroll is cast iron, the orbiting scroll, a bimetal thrust bearing that supports the orbiting scroll, and a thrust plate made of Swedish steel are slid to form a thrust bearing is known.

Alternatively, a scroll compressor in which, when a thrust load is large or when sliding characteristics are not adequate, wear and seizure between an orbiting scroll and a thrust bearing are prevented by providing an oil supply hole that extends from a boss section of the orbiting scroll to a thrust surface of the orbiting scroll and increasing an oil supply amount is known (refer to, for example, Patent Literature 1).

Still alternatively, a scroll compressor that increases wear resistance of a thrust bearing section by, at a thrust bearing surface that supports an orbiting scroll, forming a plurality of spiral groove mechanisms or a plurality of taper land bearing mechanisms and generating oil film pressure is known (refer to, for example, Patent Literature 2).

Patent Literature 1: Japanese Unexamined Patent Application Publication No. 5-149277 (paragraphs to, FIG. 1)

Patent Literature 2: Japanese Unexamined Patent Application Publication No. 8-319959 (paragraphs to, FIGS. 1 to 3)

An existing thrust bearing structure is a simple structure in which the orbiting scroll made of cast iron and the thrust plate made of Swedish steel or other materials are slid. Since a bimetal thrust bearing is not used, under a condition in which a thrust load is increased, slidability between the orbiting scroll and the thrust plate deteriorates, as a result of which a back surface (lower surface) of the orbiting scroll is subjected to, for example, wear and seizure.

The invention is made to solve the above-described problems. It is an object of the invention to provide a scroll compressor that can suppress wear and seizure of a lower surface of an orbiting scroll even if the scroll compressor has a simple structure that does not use an expensive bimetal thrust bearing.

A scroll compressor according to an embodiment of the invention includes a body container that is a hermetically sealed container; a fixed scroll that is fixed to an upper portion of an inside of the body container; an orbiting scroll that is disposed below the fixed scroll and that, together with the fixed scroll, forms a compression chamber, the orbiting scroll including a boss section at a central portion of a lower surface of the orbiting scroll; a rotary drive shaft having an eccentric shaft section formed at an upper end portion of the rotary drive shaft, the rotary drive shaft including an oil passing hole that connects an upper side and a lower side in an inside of the shaft, the eccentric shaft section being rotatably supported by an orbiting bearing at the boss section of the orbiting scroll; a frame including a thrust support surface that receives the orbiting scroll, a recessed section that is formed inwardly from the thrust support surface in a radial direction of the body container and that accommodates the boss section of the orbiting scroll, and a main bearing section that is formed at a lower portion of the recessed section and that rotatably supports the rotary drive shaft, the frame being fixed to an inner peripheral surface of the body container; a thrust plate that is disposed between the lower surface of the orbiting scroll and the thrust support surface of the frame and that slidably supports the lower surface of the orbiting scroll; an Oldham ring that is accommodated the frame and that restricts rotation of the orbiting scroll around an axis of the rotary drive shaft; and an orbiting-side Oldham groove that is formed in the lower surface of the orbiting scroll outwardly from the boss section, the orbiting-side Oldham groove accommodating a part of the Oldham ring, wherein a circumferential groove that communicates with the orbiting-side Oldham groove is formed in the lower surface of the orbiting scroll.

In the scroll compressor of an embodiment of the invention, since the circumferential groove that communicates with the orbiting-side Oldham groove is formed in the lower surface of the orbiting scroll, it is possible to supply a sufficient amount of lubricating oil between the orbiting scroll and the thrust plate, and to generate oil film pressure by the wedge effect. As a result, the advantageous effects of preventing wear and suppressing seizure at the lower surface of the orbiting scroll are obtained.

In Embodiment 1, wear and seizure of a thrust surface of an orbiting scroll are suppressed.

FIG. 1 is a vertical sectional view of a scroll compressor in Embodiment 1 of the present invention. FIG. 2 illustrates an orbiting scroll of the scroll compressor. FIG. 3 illustrates a frame of the scroll compressor. FIG. 4 is a plan view showing a state in which an Oldham ring is mounted in the frame of the scroll compressor.

In each figure, the scroll compressor according to Embodiment 1 sucks refrigerant that circulates through a refrigerant circuit, compresses the refrigerant to a state of high temperature and high pressure, and discharges the refrigerant to the refrigerant circuit. The scroll compressor includes a body container 100 that is a hermetically sealed container; a fixed scroll 101 that is fixed to and disposed at an upper portion of the inside of the body container 100; an orbiting scroll 102 that is disposed below the fixed scroll 101 and that includes a boss section 102c at a lower surface thereof; a rotary drive shaft 114 including an oil passing hole 114a that connects an upper side and a lower side in the shaft; a frame 105 that is fixed to and disposed at a container inner peripheral surface of an intermediate portion of the body container 100; a thrust plate 104 that slidably supports the orbiting scroll 102 and that has the form of a ring plate; and an oil pump 108 that is connected to a lower portion of the rotary drive shaft 114. A discharge pipe 113 for discharging refrigerant gas is connected to an upper portion of the body container 100, and a suction pipe 112 for sucking the refrigerant gas is connected to a body section of the body container 100. The oil pump 108 pumps up lubricating oil (refrigerating machine oil) 109 that accumulates at a bottom portion of the body container 100, and sends the lubricating oil to the oil passing hole 114a.

The frame 105 includes a thrust support surface 105c that supports the orbiting scroll 102, a recessed section 105b that is formed inwardly from the thrust support surface 105c in a radial direction of the container and that is used for accommodating the boss section 102c of the orbiting scroll 102, and a main bearing section 105a that is formed at a lower portion of the inside of the recessed section 105b and that rotatably supports the rotary drive shaft 114. An eccentric shaft section 110 that is rotatably supported by an orbiting bearing 102a at the boss section 102c of the orbiting scroll 102 is formed at an upper end portion of the rotary drive shaft 114. An Oldham ring 103 that restricts rotation of the orbiting scroll 102 around an axis C of the rotary drive shaft 114 is accommodated in the recessed section 105b of the frame 105. A frame-side Oldham groove 105d for guiding the Oldham ring 103 is formed in the recessed section 105b of the frame 105, with the frame-side Oldham groove 105d being long in the radial direction (refer to FIGS. 3 and 4).

The thrust plate 104 that is made of a steel-plate-based material and that slidably supports the orbiting scroll 102 is disposed between a thrust surface 102e at the lower surface of the scroll 102 and the thrust support surface 105c of the frame 105. A cutaway portion 104b that communicates with the frame-side Oldham groove 105d is formed in the thrust plate 104 at a location thereof that faces the frame-side Oldham groove 105d. The cutaway portion 104b is formed with a shape having a size that is slightly larger than that of the frame-side Oldham groove 105d. A thrust bearing section is formed by bringing the orbiting scroll 102 and the thrust plate 104 in close contact with each other via the lubricating oil 109. The thrust plate 104 has a function of adjusting a gap in a compression chamber 111 in the direction of the axis C of the rotary drive shaft.

A lap 101a that is provided vertically on a lower surface (back surface) of a base plate is formed at the fixed scroll 101. A lap 102b that is provided vertically on an upper surface of a base plate and that has substantially the same shape as the lap 101a is formed at the orbiting scroll 102. The orbiting scroll 102 and the fixed scroll 101 are made of a cast-iron-based material, and are mounted in the body container 100 with the lap 102b and the lap 101a combined with each other. With the orbiting scroll 102 and the fixed scroll 101 combined with each other, a spiral direction of the lap 101a and a spiral direction of the lap 102b are opposite each other. The compression chamber 111 whose volume changes relatively is formed between the lap 10a and the lap 9a.

The fixed scroll 101 is fixed to an opening-port edge portion at an upper surface of the frame 105 with, for example, a bolt (not shown). On the other hand, the boss section 102c having a hollow cylindrical shape extends downward from a substantially central portion of the lower surface of the orbiting scroll 102, and an inner peripheral surface of the boss section 102c corresponds to the orbiting bearing 102a. An orbiting-side Oldham groove 102d that guides an upper protrusion 103a of the Oldham ring 103 is formed at a location in the lower surface of the orbiting scroll 102 that is situated outwardly from the boss section 102c, with the orbiting-side Oldham groove 102d being long in the radial direction (refer to FIG. 2). By the Oldham ring 103 for preventing rotation movement, the orbiting scroll 102 revolves (so-called orbital movement) without rotating with respect to the fixed scroll 101.

The eccentric shaft section 110 that is provided at an upper end of the rotary drive shaft 114 is rotatably placed into the orbiting bearing 102a. By causing an inner peripheral portion of the orbiting bearing 102a and an outer peripheral portion of the eccentric shaft section 110 to slidably closely contact each other via the lubricating oil 109, an orbiting bearing section is formed. An electric motor 115 includes a rotor 106 and a stator 107, the rotor 106 being fixed to the rotary drive shaft 114 and the stator 107 being fixed to the container inner peripheral surface of the intermediate portion. By starting energization to the stator 107, the rotor 106 is rotated and driven to rotate the rotary drive shaft 114.

The rotary drive shaft 114 rotates as the rotor 106 rotates, and rotates the orbiting scroll 102. An upper portion of the rotary drive shaft 114 (location near the eccentric shaft section 10) is supported by the main bearing section 105a of the frame 105. A ball bearing 117 is mounted on a central portion of a sub-frame 116 fixed to an inner peripheral surface of a lower portion of the body container 100, and rotatably supports the lower portion of the rotary drive shaft 114. The oil pump 108 of a displacement type is mounted on the sub-frame 116. The oil pump 108 is connected to the rotary drive shaft 4, and is subjected to rotary force. The lubricating oil 109 sucked by the oil pump 108 is sent to each sliding section via, for example, the oil passing hole 114a of the rotary drive shaft 114.

Next, an operation is described.

In the scroll compressor having such a structure, when voltage is applied to the electric motor 115, the rotary drive shaft 114 is rotated and driven, and the eccentric shaft section 110 rotates in the orbiting bearing 102a. Then, the orbiting scroll 102 whose rotation is suppressed by the Oldham ring 103 undergoes orbital movement. This causes part of refrigerant gas to flow into the compression chamber 111 via a suction port of the frame 105, and a suction process is started. The remaining part of the refrigerant gas passes through a cutaway portion of the stator 106, and cools the electric motor 115 and the lubricating oil 109.

The orbital movement of the orbiting scroll 102 causes the compression chamber 111 to gradually move toward the center of the orbiting scroll 102, and its volume is further reduced. This process causes the refrigerant gas sucked into the compression chamber 111 to be compressed. At this time, the compressed refrigerant gas causes a load acting in a direction away from the fixed scroll 101 in the direction of axis C to act upon the orbiting scroll 102. However, this load is received by an upper surface 104a of the thrust plate 104. The compressed refrigerant passes through a discharge port of the fixed scroll 101 and through a discharge pipe 25, and is discharged to the refrigerant circuit from the body container 100. The lubricating oil 109 sucked up to the eccentric shaft section 110 by the oil pump 108 lubricates the sliding section of a bearing metal of the orbiting scroll 102 and the sliding section between the thrust surface 102e of the orbiting scroll 102 and the upper surface 104a of the thrust plate 104. Thereafter, part of the lubricating oil 109 flows upstream from an outer peripheral edge of the orbiting scroll 102, and flows into the compression chamber 111, lubricates the sliding section between the lap 101a and the lap 102b. The remaining part of the lubricating oil 109 flows downward from the inside of the frame 105, and returns to an oil sump at the bottom portion of the body container 100.

In the scroll compressor having the above-described structure, the lubricating oil 109 flows to a circumferential groove 102f from the orbiting scroll Oldham groove 102d each time the orbiting scroll 102 reciprocates along the orbiting-side Oldham groove 102d, and a sufficient amount of lubricating oil 109 is supplied to the thrust surface 102e from the circumferential groove 102f. Since the thrust plate 104 includes the cutaway portion 104b, a flow passage for supplying the lubricating oil 109 from the frame-side Oldham groove 105d to the thrust surface 102e each time the Oldham ring 103 reciprocates along the frame-side Oldham groove 105d is provided. In the related art, since the cutaway portion 104b described above is not formed in the thrust plate, the supply of lubricating oil from the frame-side Oldham groove to the thrust surface is hindered.

As described above, according to the scroll compressor of Embodiment 1, it is possible to increase the amount of lubricating oil 109 supplied to the thrust surface 102e, so that the wedge effect occurring due to this increase makes it possible to generate high oil film pressure. As a result, it is possible to suppress wear and seizure of the thrust surface 102e of the orbiting scroll 102.

Although, in Embodiment 1, the lower surface of the orbiting scroll is a horizontal surface without being inclined, the scroll compressor of the present invention is not limited thereto. For example, Embodiment 2 in which, as shown in FIG. 5, a thrust surface 102g of an orbiting scroll 102A that is supported by an upper surface 104a of a thrust plate 104 is an inclined surface that extends downward and outward in a radial direction is also included in the present invention.

According to the orbiting scroll 102A including the inclined thrust surface 102g as described above, since a large wedge effect is provided, it is possible to generate higher oil film pressure. This makes it possible to reliably prevent wear and seizure of the thrust surface 102e of the orbiting scroll 102.