Crankshaft and rotary compressors

Abstract

The present invention provides a crankshaft and a rotary compressor. The eccentric section of the crankshaft defines a recess in its outer circumferential surface. The recess defines an opening in the outer circumferential surface of the eccentric section and a bottom surface within the eccentric section. An orthogonal projection of the opening on a cross section of the eccentric section includes a set of arcs including at least one arc. The total length of the set of arcs is shorter than the circumference of the eccentric section. An orthogonal projection of the bottom surface on a cross section of the eccentric section includes a set of curves including at least one curve having a first endpoint and a second endpoint. A first line segment connects the first endpoint to the center of the circle defined by the eccentric section, and a second line segment connects the second endpoint to the center of the circle defined by the eccentric section. The first and second line segments define an angle α therebetween, where 0°<α≦180°. The minimum distance between the center of the circle defined by the eccentric section and the curve is equal to r, where 1 / 2≦r / R<1. This invention improves lubrication between the eccentric section and the piston, reducing power losses due to friction and improving compressor performance.

Description

[Technical Field]

[0001] The present invention relates to the field of compressor technology, in particular to crankshaft and rotary compressors. [Background technology]

[0002] A rotary compressor comprises a crankshaft, a piston, and a cylinder. The crankshaft has an eccentric section, and the piston is placed on the eccentric section within the cylinder, leaving a very small clearance between the piston and the eccentric section. The eccentric section can rotate to rotate the piston. However, during rotation, the eccentric section tends to create a large amount of friction with the piston, which leads to significant frictional power loss and reduces compressor performance. Summary of the Invention

[0003] Provided herein is a crankshaft and rotary compressor that overcomes the above-mentioned problem of high friction between the eccentric section and the piston.

[0004] To this end, the present invention provides a crankshaft including an eccentric section defining a recess on its circumference, said recess defining an opening in an outer peripheral surface of said eccentric section and a bottom surface within said eccentric section; an orthogonal projection of the opening on a cross section of the eccentric section includes a set of arcs that includes at least one arc and has a total length that is less than the circumference of the eccentric section, the cross section of the eccentric section being perpendicular to an axis of the eccentric section; An orthogonal projection of the base surface at the cross section of the eccentric section has a set of curves including one curve having a first endpoint and a second endpoint, the first endpoint connected to a center of a circle defined by the eccentric section by a first line segment, the second endpoint connected to the center of the circle defined by the eccentric section by a second line segment, the first and second line segments defining an angle α therebetween such that 0°<α≦180°, and the curve is spaced from the center of the circle defined by the eccentric section by a minimum distance r such that 1 / 2≦r / R<1, where R represents a radius of the eccentric section.

[0005] Optionally, each of the at least one curve may be a circular arc.

[0006] Optionally, the set of curves may include at least two arcs joined end to end.

[0007] Optionally, the recess may extend through the upper and lower end faces of the eccentric section.

[0008] Optionally, the recess may be perpendicular to the upper and lower end faces of the eccentric section.

[0009] Optionally, the recess may extend spirally around the circumference of the eccentric section.

[0010] Optionally, the recess may extend helically in a direction opposite to the direction in which the eccentric section rotates.

[0011] Optionally, the orthogonal projection of the bottom surface at the cross section of the eccentric section may further include a set of line segments including at least one line segment having a third endpoint and a fourth endpoint, wherein the third endpoint is connected to a center of the circle defined by the eccentric section by a third line segment, and the fourth endpoint is connected to the center of the circle defined by the eccentric section by a fourth line segment, wherein the third line segment and the fourth line segment define an angle therebetween, the angle being equal to α, and wherein the line segment is spaced apart from the center of the circle defined by the eccentric section by a minimum distance, the minimum distance being equal to r.

[0012] The present invention provides a rotary compressor comprising a crankshaft as defined in any of the preceding paragraphs.

[0013] Optionally, the rotary compressor may further include a housing, a piston, an upper cylinder cap, a cylinder, and a lower cylinder cap, wherein the eccentric section of the crankshaft and the piston are mounted in the cylinder, the piston is disposed on the eccentric section, a clearance is left between the piston and the eccentric section, the eccentric section is used to rotationally drive the piston, the upper cylinder cap is fixed to an upper end surface of the cylinder, and the lower cylinder cap is fixed to a lower end surface of the cylinder; an oil intake port provided on the axis of the crankshaft, and an oil outlet port provided on the eccentric section so as to communicate with the oil intake port; The bottom of the housing defines an oil tank, and the oil intake is used to draw lubricating oil from the oil tank.

[0014] In the crankshaft and rotary compressor of the present invention, the presence of a recess in the eccentric section reduces the contact area between the eccentric section and the piston during rotation of the piston driven by the eccentric section, thereby reducing friction. Furthermore, introducing lubricating oil into the recess enhances lubrication between the eccentric section and the piston, reducing power loss due to friction and improving compressor performance. By setting the angle α between the first and second line segments within the range of 0°<α≦180°, power loss from the eccentric section to the rotational drive of the piston due to an excessively large value of α can be prevented. By setting the minimum distance r between the center of the circle defined by the eccentric section and the curve within the range of 1 / 2≦r / R<1, the strength of the crankshaft and the lubrication of the recess can be taken into consideration, and the depth of the recess can be prevented from being excessively large or small. An excessively large recess depth can reduce the strength of the crankshaft. An insufficient recess depth can prevent the lubricating oil from being sufficiently contained to provide the desired lubrication. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a schematic cross-sectional view through an eccentric section of a crankshaft according to an embodiment of the present invention. [Figure 2] 1 is a schematic diagram illustrating a crankshaft having an eccentric section defining a recess therein, according to an embodiment of the present invention. FIG. [Figure 3] FIG. 3 is a schematic right side view of FIG. 2. [Figure 4] 1 shows a schematic diagram of a crankshaft according to an embodiment of the present invention having an eccentric section defining two recesses therein. [Figure 5] FIG. 5 is a schematic right side view of FIG. 4. [Figure 6] 1 shows a schematic diagram of a crankshaft according to an embodiment of the present invention having an eccentric section defining a recess therein. [Figure 7] FIG. 7 is a schematic right side view of FIG. 6. [Figure 8]1 is a schematic partial view of a rotary compressor according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] The objects, advantages and features of the present invention will become more apparent upon reading the detailed description of the crankshaft and rotary compressor set forth herein with reference to the accompanying drawings, in which it is noted that the figures are provided in a highly simplified form, and not necessarily drawn to scale, for the sole purpose of assisting in illustrating the disclosed embodiments in a more convenient and understandable manner.

[0017] As used herein, terms such as "first," "second," etc. are used solely for ease of description and reference and should not be construed as indicating or implying relative importance, nor should they be construed as implying a numerical number of the referenced items. Thus, defining an item with terms such as "first," "second," etc., is an explicit or implicit indication of the presence of one or more such items.

[0018] As shown in FIGS. 1 to 7 , in an embodiment of the present invention, a crankshaft 1 includes an eccentric section 11. The eccentric section 11 defines a recess 2 on its circumference. The recess 2 has an opening 21 and a bottom surface 22. The opening 21 is defined on an outer peripheral surface 111 of the eccentric section 11, and the bottom surface 22 is disposed within the eccentric section 11. An orthogonal projection of the opening 21 on a cross-section of the eccentric section 11 includes a set of arcs, the set of arcs including at least one arc. A total length of the set of arcs is shorter than the circumference of the eccentric section 11. The cross-section of the eccentric section 11 is defined perpendicular to the axis of the eccentric section 11. An orthogonal projection of the bottom surface 22 on the cross-section of the eccentric section 11 includes a set of curves, the set of curves including at least one curve having a first endpoint and a second endpoint. A first line segment connects the first endpoint to a center of the circle defined by the eccentric section 11. The second line segment connects the second endpoint and the center of the circle defined by the eccentric section 11. The first and second line segments define an angle α therebetween, which satisfies 0°<α≦180°. The minimum distance between the center of the circle defined by the eccentric section 11 and the curve is equal to r, which satisfies 1 / 2≦r / R<1, where R represents the radius of the eccentric section 11. The outer circumferential surface 111 refers to the side wall surface of the eccentric section 11, and the outer circumferential surface 111 is perpendicular to both the upper end surface 112 and the lower end surface 112 of the eccentric section 11.

[0019] In the crankshaft 1 according to these embodiments of the present invention, the eccentric section 11 of the crankshaft 1 is provided with a recess 2. The presence of the recess 2 reduces the contact area between the eccentric section 11 and the piston during rotation of the piston driven by the eccentric section 11, thereby reducing friction between the eccentric section 11 and the piston. Furthermore, lubricating oil can be introduced into the recess 2 to improve lubrication between the eccentric section 11 and the piston, reduce power loss due to friction, and improve compressor performance. By setting the angle α between the first and second line segments within the range of 0°<α≦180°, power loss from the eccentric section 11 to the driving rotation of the piston due to an excessively large value of α can be prevented. By setting the minimum distance r between the center of the circle defined by the eccentric section 11 and the curve within the range of 1 / 2≦r / R<1, the strength of the crankshaft 1 and the lubrication of the recess 2 can be considered, and an excessively large or small depth of the recess 2 can be avoided. If the recess 2 is too deep, the strength of the crankshaft 1 may be reduced. If the recess 2 is not deep enough, the recess 2 may not be able to retain enough lubricant oil to provide the desired lubrication.

[0020] Optionally, the set of curves may be a set of circular arcs, as shown in FIG. 1 . In this case, each of the curves is a circular arc. If the orthogonal projection of the bottom surface 22 of the recess 2 on the cross section of the eccentric section 11 is a circular arc, the recess 2 has a constant depth throughout. This makes it easier to machine the recess 2 in the eccentric section 11. If the orthogonal projection of the bottom surface 22 of the recess 2 on the cross section of the eccentric section 11 is a curve, the recess 2 either has a constant depth throughout or does not. In the latter case, machining the recess 2 requires changing the cutting depth of the cutter used, which may make machining more difficult. Alternatively, the recess 2 can be formed directly by casting.

[0021] Optionally, as shown in Figures 1 and 5, the set of curves may include at least two curves that are arcs joined end to end. This facilitates machining of the recesses 2. As shown in Figure 1, the set of arcs includes three arcs N1, N2, and N3. In alternative embodiments, two or more of the arcs may be spaced apart. That is, two or more recesses 2 may be spaced apart circumferentially around the eccentric section 11.

[0022] Optionally, as shown in Figures 1 and 2, recess 2 may extend through the upper and lower end faces 112 of eccentric section 11. This increases the area of ​​opening 21 of recess 2, making machining of recess 2 easier.

[0023] Optionally, as shown in Figures 2 and 4, the recess 2 may be perpendicular to the upper end surface and the lower end surface 112 of the eccentric section 11. This makes machining of the recess 2 easier.

[0024] Optionally, as shown in Figures 1 and 6, recess 2 may extend spirally along the circumferential direction of eccentric section 11. Referring to Figures 6 and 7, if crankshaft 1 is designed to rotate counterclockwise, recess 2 extends spirally clockwise from the side of the long section of crankshaft 1 to the side of the short section. This allows more lubricating oil to be stored in recess 2 during rotation of eccentric section 11.

[0025] Optionally, referring to FIG. 1 , the orthogonal projection of the bottom surface 22 of the recess 2 on the cross section of the eccentric section 11 may further include a set of line segments, the set of line segments including at least one line segment having a third endpoint and a fourth endpoint. The third line segment connects the third endpoint to the center of the circle defined by the eccentric section 11, and the fourth line segment connects the fourth endpoint to the center of the circle defined by the eccentric section 11. The third line segment and the fourth line segment define an angle therebetween, the angle being equal to α. The minimum distance between the line segment and the center of the circle defined by the eccentric section 11 is r. Alternatively, the orthogonal projection of the bottom surface 22 of the recess 2 on the cross section of the eccentric section 11 may be a combination of curved and straight lines. In this manner, various crankshaft configurations 1 can be provided, and therefore, various compressor configurations with different performance specifications can also be provided.

[0026] Based on the same inventive concept as the crankshaft 1 described above, an embodiment of the present invention also provides a rotary compressor including the crankshaft 1 defined in any of the paragraphs above, as shown in FIG. 8.

[0027] In the crankshaft 1 of the rotary compressor according to these embodiments of the present invention, the eccentric section 11 of the crankshaft 1 is provided with a recess 2. The presence of the recess 2 reduces the contact area between the eccentric section 11 and the piston during rotation of the piston driven by the eccentric section 11, thereby reducing friction between the eccentric section 11 and the piston. Furthermore, lubricating oil can be introduced into the recess 2 to improve lubrication between the eccentric section 11 and the piston, reducing power loss due to friction and improving compressor performance. By setting the angle α between the first and second line segments within the range of 0°<α≦180°, power loss from the eccentric section 11 to the driving rotation of the piston due to an excessively large value of α can be prevented. By setting the minimum distance r between the center of the circle defined by the eccentric section 11 and the curve within the range of 1 / 2≦r / R<1, the strength of the crankshaft 1 and the lubrication of the recess 2 can be considered, and an excessively large or small depth of the recess 2 can be avoided. An excessively large depth of recess 2 may reduce the strength of crankshaft 1. An insufficient depth of recess 2 may not accommodate enough lubricant oil to provide the desired lubrication.

[0028] Optionally, as shown in FIGS. 1 and 8 , the rotary compressor may further include a housing, a piston, an upper cylinder cap 3, a cylinder 4, and a lower cylinder cap 5. The eccentric section 11 of the crankshaft 1 and the piston are mounted in the cylinder 4, with the piston positioned above the eccentric section 11, leaving a clearance between the piston and the eccentric section 11. The eccentric section 11 is used to rotate the piston. The upper cylinder cap 3 is fixed to the upper end surface of the cylinder 4, and the lower cylinder cap 5 is fixed to the lower end surface 112 of the cylinder 4. An oil intake port is provided on the axis of the crankshaft 1, and an oil outlet 113 is provided in the eccentric section 11, which is connected to the oil intake port. The bottom of the housing forms an oil tank, and the oil intake port is used to draw lubricating oil from the oil tank. The lubricating oil enters the clearance between the eccentric section 11 and the piston through the oil inlet and oil outlet, and flows into the recess 2, thereby enhancing the lubrication between the eccentric section 11 and the piston, reducing the power loss caused by friction, and improving the performance of the compressor.

[0029] Therefore, in the crankshaft 1 and rotary compressor according to the present invention, the eccentric section 11 of the crankshaft 1 is provided with a recess 2. During rotation of the piston driven by the eccentric section 11, the presence of the recess 2 reduces the contact area between the eccentric section 11 and the piston, thereby reducing friction between the eccentric section 11 and the piston. Furthermore, lubricating oil can be introduced into the recess 2 to improve lubrication between the eccentric section 11 and the piston, reducing power loss due to friction and improving compressor performance. By setting the angle α between the first and second line segments within the range of 0°<α≦180°, power loss from the eccentric section 11 to the driving rotation of the piston due to an excessively large value of α can be prevented. By setting the minimum distance r between the center of the circle defined by the eccentric section 11 and the curve within the range of 1 / 2≦r / R<1, the strength of the crankshaft 1 and the lubrication of the recess 2 can be considered, and the depth of the recess 2 can be prevented from being excessively large or small. If the depth of the recess 2 is excessively large, it may reduce the strength of the crankshaft 1. If the depth of the recess 2 is insufficient, it may not be possible to retain enough lubricant in the recess 2 to provide the desired lubrication.

[0030] The above merely describes some preferred embodiments of the present invention, and is not intended to limit the scope of the present invention in any way. Any changes and modifications made by those skilled in the art in light of the above teachings shall be included within the scope of the present invention. [Explanation of symbols]

[0031] 1: Crankshaft 2: Recess 3: Upper cylinder cap 4: Cylinder 5: Lower cylinder cap 11: Eccentric section 111: Outer surface 112: Bottom end surface 113: Oil outlet 21:Aperture 22: Bottom.

Claims

1. A crankshaft comprising an eccentric section, the eccentric section having a circumferential recess defining an opening and a bottom surface, the opening being formed in an outer peripheral surface of the eccentric section and the bottom surface being formed within the eccentric section, an orthogonal projection of the opening on a cross-section of the eccentric section includes a set of arcs, the set of arcs having at least one arc, a total length of the set of arcs being less than a circumference of the eccentric section, and the cross-section of the eccentric section being perpendicular to an axis of the eccentric section; an orthogonal projection of the bottom surface of the eccentric section at the cross section includes a set of curves, the set of curves including at least one curve, each curve having a first endpoint and a second endpoint, the first endpoint being connected to a center of a circle defined by the eccentric section by a first line segment, the second endpoint being connected to the center of the circle defined by the eccentric section by a second line segment, the first line segment and the second line segment defining an angle α therebetween, satisfying 0°<α≦180°, the curves being spaced apart from the center of the circle defined by the eccentric section by a minimum distance r, satisfying ½≦r / R<1, where R represents a radius of the eccentric section.

2. 10. The crankshaft of claim 1, wherein each of the at least one curved line is a circular arc.

3. The crankshaft of claim 1 , wherein the set of curves includes at least two arcs joined end to end.

4. The crankshaft of claim 1 , wherein the recess extends through both an upper end surface and a lower end surface of the eccentric section.

5. The crankshaft of claim 1 , wherein the recess is perpendicular to both the upper and lower end faces of the eccentric section.

6. The crankshaft of claim 1 , wherein the recess extends spirally around the circumference of the eccentric section.

7. 7. The crankshaft of claim 6, wherein the recess extends spirally in a direction opposite to the direction that the eccentric section rotates.

8. 2. The crankshaft of claim 1, wherein the orthogonal projection of the bottom surface at the cross section of the eccentric section further includes a set of line segments, the set of line segments including at least one line segment having a third endpoint and a fourth endpoint, the third endpoint connected to a center of the circle defined by the eccentric section at a third line segment, and the fourth endpoint connected to the center of the circle defined by the eccentric section at a fourth line segment, the third line segment and the fourth line segment defining an angle therebetween that is equal to α, and the line segment is spaced a minimum distance from the center of the circle defined by the eccentric section, the minimum distance being equal to r.

9. A rotary compressor comprising the crankshaft according to any one of claims 1 to 8.

10. The crankshaft further includes a housing, a piston, an upper cylinder cap, a cylinder, and a lower cylinder cap, wherein the eccentric section of the crankshaft and the piston are mounted in the cylinder, the piston is disposed on the eccentric section, a clearance is left between the piston and the eccentric section, the eccentric section is used to rotate the piston, the upper cylinder cap is fixed to an upper end surface of the cylinder, and the lower cylinder cap is fixed to a lower end surface of the cylinder; an oil intake port provided on the axis of the crankshaft, and an oil outlet port provided on the eccentric section, the oil outlet port communicating with the oil intake port; 10. The rotary compressor of claim 9, wherein the bottom of the housing defines an oil tank, and the oil inlet is used to draw lubricating oil from the oil tank.

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