Asymmetric connecting rod and mounting structure thereof

Abstract

The utility model discloses an asymmetric connecting rod and a mounting structure thereof, the asymmetric connecting rod comprises a rod body part, the rod body part is linear, two ends of the rod body part are provided with a large head part and a small head part, the middle part of the large head part is provided with a connecting rod large hole, and the middle part of the small head part is provided with a connecting rod small hole used for connecting a piston. The connecting line of the circle centers of the large connecting rod hole and the small connecting rod hole is parallel to the central axis of the rod body part, the horizontal distance between the connecting line and the central axis is not smaller than 1 mm, and a shaft sleeve used for being connected with a crankshaft is in interference fit with the interior of the large connecting rod hole; the utility model has the advantages of strong load capacity, good wear resistance and simple structure.

Description

Technical Field

[0001] The utility model belongs to the technical field of compressor components, and particularly relates to an asymmetric connecting rod and a mounting structure thereof. Background Art

[0002] Compressors can be divided into positive displacement compressors and speed compressors according to their principle. Positive displacement compressors are further divided into reciprocating compressors and rotary compressors; speed compressors are further divided into axial flow compressors, centrifugal compressors and mixed flow compressors.

[0003] Today, household refrigerator and air conditioner compressors are all positive displacement compressors, which can be divided into reciprocating and rotary types. Reciprocating compressors use a piston, crank, connecting rod mechanism or a piston, crank, sliding tube mechanism, while rotary compressors mostly use rolling rotor compressors.

[0004] Existing large-scale commercial compressors mostly use R290 working fluid. The ambient temperature is high, the load is heavy, and the heat generated by the compressor is also large. The starting performance requirements of the compressor are increasingly higher. The connecting rod body of conventional compressors is symmetrical relative to the connecting rod big end hole and is designed to be parallel to the center line of the connecting rod big end hole. The ordinary connecting rod design is symmetrical. When the compressor is started under high load conditions, or under some special strength and unbalanced stress conditions, the starting torque of the connecting rod cannot meet its use requirements.

[0005] The problem with the existing technology is that ordinary connecting rod designs are all bilaterally symmetrical, with the rod body and the centers of the large and small holes arranged in a collinear manner. When this structure is in operation, the piston, crankshaft and connecting rod are in the same straight line, and it is easy for them to get stuck when running at the upper and lower dead points, affecting the operating torque and load capacity of the compressor; in the second half of the piston compression stroke, under the action of the connecting rod component force, the positive pressure between the piston and the cylinder seat hole wall is relatively large, the friction is increased, and it is easy to cause wear. Summary of the Invention

[0006] The purpose of the utility model is to address the problems existing in the prior art and to provide an asymmetric connecting rod and its installation structure, which have the advantages of strong load capacity, good wear resistance and simple structure.

[0007] To achieve the above-mentioned purpose, the technical solution adopted by the utility model is: an asymmetric connecting rod and its installation structure, including a rod body part, the rod body part is linear, and a large head and a small head are provided at both ends of the rod body part. A large connecting rod hole is opened in the middle of the large head part, and a small connecting rod hole for connecting the piston is opened in the middle of the small head part. The line connecting the center of the large connecting rod hole and the small connecting rod hole is parallel to the central axis of the rod body part and the horizontal spacing is not less than 1 mm. A shaft sleeve for connecting the crankshaft is interference-connected in the large connecting rod hole.

[0008] In the above scheme, the rod body connects the large head and the small head at both ends, and a sleeve is set in the large hole of the connecting rod of the large head to be rotatably connected to the crankshaft. The crankshaft power is transmitted from the large head to the side of the small head through the rod body, and the piston is driven to move through the small hole of the connecting rod. The line connecting the centers of the large hole of the connecting rod and the small hole of the connecting rod is parallel to the central axis of the rod body and a distance is set to realize the offset setting of the rod body. This structural setting can bias the driving force transmitted by the connecting rod when the compressor is started or running, avoid the piston, crankshaft and connecting rod being in the same straight line, avoid upper and lower dead points, thereby increasing the torque of the compressor and enhancing the load capacity of the compressor. For large-sized compressors using a larger crankshaft diameter, a sleeve is set in the large hole of the connecting rod to improve the wear resistance and service life of the connecting rod.

[0009] Furthermore, the width of the shaft is equal to the diameter of the connecting rod hole, and the horizontal distance between the center line of the connecting rod large hole and the connecting rod small hole and the central axis of the shaft is equal to the adjustment coefficient k*connecting rod hole diameter, 0.1≤adjustment coefficient k≤0.3.

[0010] The width of the rod body is equal to the diameter of the connecting rod hole. Under the premise of ensuring the force conduction bias of the rod body, the structural strength of the rod body is guaranteed. By adjusting the coefficient k to control the corresponding spacing value according to the connecting rod hole diameter, the bias effect of force conduction is guaranteed.

[0011] Furthermore, both ends of the shaft are provided with reinforced connection parts for connecting with the large head or the small head, and the reinforced connection parts include a curved surface structure.

[0012] The connection stability between the shaft and the large and small heads is enhanced by strengthening the connection portion, and a curved surface structure is provided to achieve a smooth transition between the shaft and the large and small heads to avoid stress concentration.

[0013] Furthermore, the arc surface structure is provided on the upper and lower sides and the horizontal side of the shaft, which has a simple structure and good stability.

[0014] Furthermore, annular grooves are provided at both ends of the connecting rod hole, and the end faces of the large head and the small head are flush with each other. The annular grooves are provided to facilitate the positioning and connection of the piston pin, and the flush end faces facilitate the positioning and installation of parts.

[0015] Furthermore, the center distance between the connecting rod large hole and the connecting rod small hole is in the range of 40mm-60mm, the inner hole diameter of the sleeve is in the range of 25mm-35mm, and the diameter of the connecting rod small hole is in the range of 10mm-16mm.

[0016] An installation structure for an asymmetric connecting rod as described above includes a cylinder seat, a crankshaft rotatably arranged at the bottom of the cylinder seat, an eccentric shaft of the crankshaft rotatably connected to the inner hole of the sleeve, a piston slidably arranged on the front side of the cylinder seat, the piston and the small head are rotatably connected by a piston pin, and the offset direction of the central axis of the rod body relative to the line connecting the centers of the circles is consistent with the direction of the compressed side of the inner wall of the cylinder hole of the cylinder seat during the compression stroke of the piston.

[0017] In the described solution, the wear resistance of the connecting rod is improved by a shaft sleeve, thereby increasing its service life. The crankshaft is driven to rotate by a motor, which drives the connecting rod to move, and the connecting rod then drives the piston to move. During the piston compression stroke, the piston is driven by the connecting rod to press against the inner wall of the cylinder bore. The rod body is biased toward the pressure side of the inner wall of the cylinder bore, which generates centripetal force under the action of the piston pin, thereby reducing the pressure on the inner wall of the cylinder bore.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. By aligning the connecting line of the connecting rod's large and small holes with the center axis of the connecting rod, the piston, crankshaft, and connecting rod can be prevented from being aligned during compressor startup or operation, avoiding upper and lower dead points, thereby increasing compressor torque and enhancing the compressor's load capacity.

[0020] 2. By setting the rod body in parallel offset, the connection point between the rod body and the large and small heads is changed. During the compression stroke, the positive pressure between the piston and the cylinder bore side wall is reduced, reducing the wear of the cylinder seat and piston, extending the service life, and increasing the force component of the piston in the compression direction, thereby improving the operating efficiency of the compressor;

[0021] 3. By offsetting the rod body, the force transmission mode of the connecting rod is changed, the structure is simple and the manufacturing is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a three-dimensional diagram of an asymmetric connecting rod in an embodiment of the present utility model;

[0023] Figure 2 This is a top view of an asymmetric connecting rod in an embodiment of the present utility model;

[0024] Figure 3 Schematic top view of an asymmetric connecting rod installation structure in an embodiment of the present utility model;

[0025] In the figure: 1. Rod body; 2. Big head; 3. Small head; 4. Big hole of connecting rod; 5. Small hole of connecting rod; 6. Central axis; 7. Line connecting the centers of circles; 8. Bushing; 9. Arc surface structure; 10. Annular groove; 11. Crankshaft; 12. Cylinder seat; 13. Piston pin; 14. Piston. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solution of the present invention in conjunction with the drawings in the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. In the description of the present invention, it should be noted that the terms front, back, left, right, etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, or are the directions or positional relationships in which the utility model product is usually placed when in use. They are only for the convenience of describing the present invention or simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed or operated in a specific direction, and therefore cannot be understood as a limitation on the present invention. Example

[0027] like Figure 1-2 As shown, an asymmetric connecting rod includes a rod body 1, which is straight. A large head 2 and a small head 3 are provided at both ends of the rod body 1. A large connecting rod hole 4 is opened in the middle of the large head 2, and a small connecting rod hole 5 for connecting to a piston 14 is opened in the middle of the small head 3. The line 7 connecting the centers of the large connecting rod hole 4 and the small connecting rod hole 5 is parallel to the central axis 6 of the rod body 1 and the horizontal spacing L is not less than 1 mm. A sleeve 8 for connecting to a crankshaft 11 is interference-connected in the large connecting rod hole 4.

[0028] In the above scheme, the rod body 1 connects the large head 2 and the small head 3 at both ends, and a sleeve 8 is set in the large connecting rod hole 4 of the large head 2 to be rotatably connected to the crankshaft 11. The power of the crankshaft 11 is transmitted from the large head 2 to the side of the small head 3 through the rod body 1, and the piston 14 is driven to move through the connecting rod small hole 5 of the small head 3. The center line 7 of the connecting rod large hole 4 and the connecting rod small hole 5 is parallel to the central axis 6 of the rod body 1 and a distance is set to realize the offset setting of the rod body 1. This structural setting can bias the driving force transmitted by the connecting rod when the compressor is started or running, avoiding the piston 14, crankshaft 11 and connecting rod being in the same straight line, avoiding upper and lower dead points, thereby increasing the compressor torque and enhancing the load capacity of the compressor. For large-sized compressors, the crankshaft 11 with a larger shaft diameter is used, and a sleeve 8 is set in the large connecting rod hole 4 to improve the wear resistance and service life of the connecting rod.

[0029] The large head 2 and the small head 3 are both annular structures.

[0030] Furthermore, the width of the shaft portion 1 is equal to the diameter of the connecting rod hole 5, and the horizontal distance L between the center line 7 of the connecting rod large hole 4 and the connecting rod hole 5 and the central axis 6 of the shaft portion 1 is equal to the adjustment coefficient k*the diameter of the connecting rod hole 5, 0.1≤adjustment coefficient k≤0.3.

[0031] The width of the shaft portion 1 is equal to the diameter of the connecting rod hole 5. Under the premise of ensuring the force conduction bias of the shaft portion 1, the structural strength of the shaft portion 1 is guaranteed. By adjusting the coefficient k to control the corresponding spacing value according to the diameter of the connecting rod hole 5, the bias effect of force conduction is guaranteed.

[0032] The thickness of the shaft portion 1 is smaller than the thickness of the big head portion 2 , and the adjustment coefficient k is preferably 0.185.

[0033] Furthermore, both ends of the shaft portion 1 are provided with reinforced connection portions for connecting with the large head portion 2 or the small head portion 3 , and the reinforced connection portions include a curved surface structure 9 .

[0034] The connection stability between the shaft 1 and the large head 2 and small head 3 is enhanced by strengthening the connection part, and the arc surface structure 9 is provided to achieve a smooth transition between the shaft 1 and the large head 2 and small head 3 to avoid stress concentration.

[0035] Furthermore, the arc surface structure 9 is provided on the upper and lower side surfaces and the horizontal side surface of the shaft portion 1. The structure is simple and the stability is good.

[0036] Furthermore, an annular groove 10 is provided at both ends of the connecting rod hole 5, and the end surfaces of the large head 2 and the small head 3 are flush with each other. The annular groove 10 is provided to facilitate the positioning and connection of the piston pin 13, and the flush end surfaces facilitate the positioning and installation of parts.

[0037] Furthermore, the center distance between the connecting rod large hole 4 and the connecting rod small hole 5 is in the range of 40mm-60mm, the inner hole diameter of the sleeve 8 is in the range of 25mm-35mm, and the diameter of the connecting rod small hole 5 is in the range of 10mm-16mm.

[0038] The inner diameter of the sleeve 8 is preferably 30 mm, and the diameter of the connecting rod hole 5 is preferably 13 mm.

[0039] like Figure 3 As shown, an installation structure of the above-mentioned asymmetric connecting rod includes a cylinder base 12, a crankshaft 11 is rotatably provided at the bottom of the cylinder base 12, the eccentric shaft of the crankshaft 11 is rotatably connected to the inner hole of the sleeve 8, a piston 14 is slidably provided on the front side of the cylinder base 12, and the piston 14 is rotatably connected to the small head 3 through a piston pin 13, and the offset direction of the central axis 6 of the rod body 1 relative to the center line 7 is consistent with the direction of the compressed side of the cylinder hole inner wall of the cylinder base 12 during the compression stroke of the piston 14.

[0040] In the described solution, the sleeve 8 is used to improve the wear resistance of the connecting rod and increase its service life. The crankshaft 11 is driven to rotate by the motor, and the crankshaft 11 drives the connecting rod to move, and then the connecting rod drives the piston 14 to move. During the compression stroke of the piston 14, the piston 14 is pressed against the inner wall of the cylinder hole by the drive of the connecting rod. The rod body 1 is biased toward the pressure side of the inner wall of the cylinder hole, which will form a centripetal force under the action of the piston pin 13, thereby reducing the pressure on the inner wall of the cylinder hole.

[0041] On the basis of ensuring that the connecting rod holes remain unchanged, the rod body is offset parallel to the center line of the connecting rod holes to form a new asymmetric connecting rod. The new connecting rod should meet the following requirements:

[0042] 1. Suitable for high temperature and high pressure environment in compressor;

[0043] 2. Its size cannot be significantly changed, which will affect the working space of the entire mechanism or cause new interference with the operation of other parts;

[0044] 3. The offset distance of the connecting rod should ensure that when the connecting rod transmits the force from the large hole 4 to the small hole 5, the stress is still concentrated on the center line of the two holes.

[0045] 4. To ensure greater energy efficiency during the second half of the connecting rod's compression stroke, the connecting rod's offset should align with the motor's rotational direction during this period. Furthermore, to ensure connecting rod strength, the casting fillet at the connection between the connecting rod's large hole (4) and the connecting rod's body is appropriately increased. To effectively utilize the crankshaft's (11) torque transmission and reduce losses, the connecting rod's body is offset slightly toward the motor.

[0046] The stroke of the piston 14 changes. Because the crankshaft 11, piston 14, and connecting rod are not aligned, the positions of the connecting rod and piston 14 differ from those of conventional engines when the crankshaft 11 rotates, resulting in a longer stroke for the piston 14. This longer stroke of the piston 14 in the cylinder theoretically improves the engine's torque performance, thereby increasing the overall torque output.

[0047] This invention offsets the connecting rod's shaft by shifting its centerline parallel to the centerlines of its large and small holes. When the connecting rod is in the second half of its compression stroke, the motor torque approaches its maximum. While the eccentric connecting rod transmits power, the offset creates a stress intensity difference on both sides of the shaft. This creates a bending stress on the offset side of the connecting rod, directed toward the large and small holes. This improves press performance in two key ways:

[0048] ① The bending stress converts part of the force into compression work on the piston 14, thereby improving the torque efficiency of the motor;

[0049] ② The effect of bending stress will generate a centripetal force in the direction of the cylinder bore diameter, reducing the positive pressure on the cylinder wall, thereby reducing friction, reducing wear, and increasing useful work.

[0050] At the same time, since the connecting rod body is still straight, the pressure it receives is more uniform compared to the special-shaped connecting rod with a bend, and stress concentration will not occur at the bend to damage the connecting rod.

[0051] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An asymmetric connecting rod, characterized in that: It includes a rod body part, which is straight, and a large head and a small head are provided at both ends of the rod body. A large connecting rod hole is opened in the middle of the large head, and a small connecting rod hole for connecting the piston is opened in the middle of the small head. The line connecting the centers of the large connecting rod hole and the small connecting rod hole is parallel to the central axis of the rod body and the horizontal spacing is not less than 1 mm. A sleeve for connecting the crankshaft is interference-connected in the large connecting rod hole.

2. The asymmetric connecting rod according to claim 1, characterized in that: The width of the shaft portion is equal to the diameter of the connecting rod small hole, and the horizontal distance between the center line of the connecting rod large hole and the connecting rod small hole and the central axis of the shaft portion is equal to the adjustment coefficient k*connecting rod small hole diameter, 0.1≤adjustment coefficient k≤0.

3.

3. The asymmetric connecting rod according to claim 1, characterized in that: Both ends of the shaft are provided with reinforced connection parts for connecting with the large head or the small head, and the reinforced connection parts include a curved surface structure.

4. The asymmetric connecting rod according to claim 3, characterized in that: The arc surface structure is arranged on the upper and lower side surfaces and the horizontal side surface of the shaft portion.

5. The asymmetric connecting rod according to claim 1, characterized in that: Annular grooves are provided at both ends of the connecting rod hole, and the end surfaces of the large head and the small head are flush with each other.

6. The asymmetric connecting rod according to claim 1, characterized in that: The center distance between the connecting rod large hole and the connecting rod small hole is in the range of 40mm-60mm, the inner hole diameter of the sleeve is in the range of 25mm-35mm, and the diameter of the connecting rod small hole is in the range of 10mm-16mm.

7. An asymmetric connecting rod installation structure according to any one of claims 1 to 6, characterized in that: It includes a cylinder seat, a crankshaft is rotatably provided at the bottom of the cylinder seat, the eccentric shaft of the crankshaft is rotatably connected to the inner hole of the sleeve, a piston is slidably provided on the front side of the cylinder seat, the piston and the small head are rotatably connected by a piston pin, and the offset direction of the central axis of the rod body relative to the center line is consistent with the pressure side direction of the cylinder hole side wall of the cylinder seat during the piston compression stroke.

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