Manufacturing process of eccentric cross head pin and eccentric cross head pin

Abstract

The invention relates to the technical field of machining, and particularly discloses a manufacturing process of an eccentric crosshead pin and the eccentric crosshead pin, the uneven weight distribution of the eccentric crosshead pin is balanced through a counterweight rod and an insert, and the two ends of the eccentric crosshead pin are respectively provided with a top plate to realize double-tip positioning of a grinding machine. In the grinding and polishing process, the dynamic balance performance of the eccentric cross head pin provided with the balance weight rod and the insert is good, grinding machining is met, and meanwhile jumping and surface quality meet quality requirements.

Description

Technical Field

[0001] This invention relates to the field of machining technology, and in particular to a manufacturing process for an eccentric crosshead pin and an eccentric crosshead pin itself. Background Technology

[0002] As a crucial moving component of marine engines, the crosshead pin requires high machining precision. Traditional machining processes are cumbersome and time-consuming. To address this, related technologies offer optimized processes that significantly reduce procedures and steps, shortening manufacturing time. However, with the advancement of marine engine technology and the increasing use of methanol engines, the crosshead pins in methanol engines require a more lightweight design and smoother rotational motion. The traditional crosshead pin's center hole is designed to be eccentric, achieving dynamic balance at the notch plane during use, resulting in an eccentric crosshead pin structure. This structure cannot be manufactured using existing processes. The main issue is that the grinding process in those technologies uses double centers to hold the center hole in place, while a single eccentric crosshead pin cannot achieve dynamic balance when rotating along its axis of rotation. Therefore, the existing processes cannot be applied to machining eccentric crosshead pins; forcing the process will only lead to runout and compromised surface quality.

[0003] Therefore, there is an urgent need for a manufacturing process for eccentric crosshead pins to meet the requirements of eccentric crosshead pin processing and manufacturing. Summary of the Invention

[0004] The purpose of this invention is to provide a manufacturing process for an eccentric crosshead pin and an eccentric crosshead pin that meets processing requirements while ensuring that runout and surface quality meet quality standards.

[0005] This invention provides a manufacturing process for an eccentric crosshead pin, comprising the following steps:

[0006] Step 1: Position the eccentric crosshead pin axially on a horizontal boring machine and lock it radially; machine the holes on the two end faces of the eccentric crosshead pin; and machine the notch plane of the eccentric crosshead pin.

[0007] Step 2: Vertically clamp one end of the eccentric crosshead pin on the milling center and turn the outer diameter. Then clamp the other end of the workpiece and turn the outer diameter.

[0008] Step 3: Fix the eccentric crosshead pin on the rotary table of the vertical boring machine, finish machine the notch plane, and machine the hole on the circumference of the eccentric crosshead pin;

[0009] Step 4: Install a counterweight bar in the eccentric hole of the eccentric crosshead pin, fix the insert at the notch plane, and install top plates at both ends of the eccentric crosshead pin.

[0010] Step 5: Place the two centers of the grinding machine against the two center holes of the top plate respectively, and drive the eccentric crosshead pin to rotate through the chuck and transmission rod of the grinding machine to grind the eccentric crosshead pin;

[0011] Step 6: Place the two tips of the polishing machine against the tip holes of the two top plates respectively, and drive the eccentric crosshead pin to rotate through the chuck and transmission rod of the polishing machine to polish the eccentric crosshead pin.

[0012] As a preferred technical solution for the manufacturing process of the eccentric crosshead pin, step one specifically involves: machining the weight reduction holes and eccentric holes on the two end faces of the eccentric crosshead pin, machining the process mounting holes on the notch plane, and fixing the insert at the notch plane through the process mounting holes.

[0013] As a preferred technical solution for the manufacturing process of the eccentric crosshead pin, step two specifically involves: clamping the first end of the eccentric crosshead pin, turning the outer diameter to a preset length, finishing the weight-reducing hole at the second end, and machining the locating pin hole and threaded hole at the second end; clamping the second end of the eccentric crosshead pin, turning the remaining portion of the outer diameter, finishing the weight-reducing hole at the first end, and machining the locating pin hole and threaded hole at the first end; the top plate is positioned and installed with the eccentric crosshead pin through the locating pin hole and the threaded hole.

[0014] As a preferred technical solution for the manufacturing process of the eccentric crosshead pin, when clamping the second end of the eccentric crosshead pin, the jaws are corrected according to the machined outer circle.

[0015] As a preferred technical solution for the manufacturing process of the eccentric crosshead pin, the two ends of the counterweight bar are respectively provided with annular grooves, and a sealing ring is installed in the annular groove, the sealing ring abutting against the wall of the eccentric hole.

[0016] As a preferred technical solution for the manufacturing process of the eccentric crosshead pin, the two ends of the counterweight bar are fixedly connected to limit baffles by bolts, the limit baffles are in contact with the two ends of the counterweight bar, and part of the limit baffles is in close contact with the bottom wall of the weight reduction hole.

[0017] As a preferred technical solution for the manufacturing process of the eccentric crosshead pin, the total weight of the counterweight bar, the two sealing rings, the two limiting baffles and the bolt is determined after the insert and the two top plates are installed on the eccentric crosshead pin.

[0018] As a preferred technical solution for the manufacturing process of the eccentric crosshead pin, an adjusting shim is also provided between the insert and the notch plane of the eccentric crosshead pin.

[0019] As a preferred technical solution for the manufacturing process of the eccentric crosshead pin, before grinding the eccentric crosshead pin, a fixed-point test grinding is performed on the eccentric crosshead pin and the circular runout at the fixed-point test grinding position is measured.

[0020] This invention provides an eccentric crosshead pin, which is manufactured using the manufacturing process of any of the above-described eccentric crosshead pins.

[0021] The beneficial effects of this invention are as follows:

[0022] This invention provides a manufacturing process for an eccentric crosshead pin. The uneven weight distribution of the eccentric crosshead pin is balanced by a counterweight and inserts. The pin is positioned using the double centers of a grinding machine by installing top plates at both ends. During grinding and polishing, the eccentric crosshead pin equipped with the counterweight and inserts exhibits good dynamic balance, ensuring that both runout and surface quality meet the requirements of the grinding process. Attached Figure Description

[0023] Figure 1 This is a top view of the eccentric crosshead pin in an embodiment of the present invention;

[0024] Figure 2 This is a cross-sectional view of the eccentric crosshead pin in an embodiment of the present invention;

[0025] Figure 3 This is a cross-sectional view of the eccentric crosshead pin during the grinding and polishing process in an embodiment of the present invention.

[0026] Figure 4 This is a cross-sectional view of the counterweight bar and the limiting baffle in an embodiment of the present invention;

[0027] Figure 5 This is a side view of the insert in an embodiment of the present invention;

[0028] Figure 6 This is a cross-sectional view of the top plate in an embodiment of the present invention.

[0029] In the picture:

[0030] 100. Eccentric crosshead pin; 110. Weight reduction hole; 120. Eccentric hole; 130. Notched plane;

[0031] 1. Counterweight bar; 11. Circular groove; 2. Limiting baffle; 3. Insert; 4. Top plate; 41. Center hole;

[0032] 10. Chuck; 20. Center; 30. Transmission rod. Detailed Implementation

[0033] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions. Furthermore, "above," "on top of," and "over" the first feature in relation to the second feature includes the first feature directly above and diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "under," and "below" the first feature in relation to the second feature includes the first feature directly below and diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0036] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0037] like Figure 1 and Figure 2As shown, by setting the eccentric hole 120, the eccentric crosshead pin 100 can achieve good dynamic balance after being assembled into the engine. Meanwhile, weight-reducing holes 110 are set at both ends to improve weight reduction. However, during processing, due to its uneven weight distribution, excessive runout and insufficient surface finish after processing can easily occur. Therefore, this embodiment provides a manufacturing process for the eccentric crosshead pin to meet processing requirements while ensuring runout and surface finish. Specifically, as... Figures 1 to 6 As shown, the manufacturing process of the eccentric crosshead pin includes the following steps:

[0038] Step 1: On a horizontal boring machine, axially position the eccentric crosshead pin 100 and lock it radially. Machin the holes on the two end faces of the eccentric crosshead pin 100 and machine the notch plane 130 of the eccentric crosshead pin 100.

[0039] Step 2: Vertically clamp one end of the eccentric crosshead pin 100 on the milling and turning center, and turn the outer diameter. Then clamp the other end of the workpiece and turn the outer diameter.

[0040] Step 3: Fix the eccentric crosshead pin 100 on the rotary table of the vertical boring machine, finish machine the notch plane 130, and machine the hole on the circumference of the eccentric crosshead pin 100.

[0041] Step 4: Install counterweight 1 in the eccentric hole 120 of the eccentric crosshead pin 100, fix the insert 3 at the notch plane 130, and install top plates 4 at both ends of the eccentric crosshead pin 100.

[0042] Step 5: Place the two centers 20 of the grinding machine against the center holes 41 of the two top plates 4 respectively, and drive the eccentric crosshead pin 100 to rotate through the chuck 10 and transmission rod 30 of the grinding machine to grind the eccentric crosshead pin 100.

[0043] Step 6: Place the two tips 20 of the polishing machine against the tip holes 41 of the two top plates 4 respectively, and drive the eccentric crosshead pin 100 to rotate through the chuck 10 and transmission rod 30 of the polishing machine to polish the eccentric crosshead pin 100.

[0044] Before step one, the short rod-shaped blank of the eccentric crosshead pin 100 is scribed and then axially positioned on a horizontal boring machine. This can be achieved using existing structures such as V-shaped positioning blocks. It is then radially locked to prevent displacement or rotation during machining. Similarly, related structures for radial locking are also existing technologies in this field, such as hand-operated hoists, and will not be described in detail here. The milling and turning center in step two allows for turning and milling of the workpiece processed in step one, reducing the number of steps and clamping operations. The vertical boring machine and rotary table in step three enable better machining of the notch plane 130 and the radial holes on the circumference. Vertical workpiece fixation provides greater stability and helps improve the accuracy of the machined holes. In step four, the counterweight 1, insert 3, and top plate 4 are installed using clamping or similar methods, ensuring that the center of gravity of the eccentric crosshead pin 100 falls on the center of rotation and that its dynamic balance during rotation around the center of rotation meets requirements, reducing runout during subsequent machining. During grinding and polishing in steps five and six, the dynamic balance during the process is good due to the setting of counterweight 1 and insert 3. This ensures that the running out and surface quality meet the quality requirements while satisfying the grinding process.

[0045] Further, step one specifically involves: machining the weight-reducing holes 110 on both end faces of the eccentric crosshead pin 100, and machining the eccentric hole 120 of the eccentric crosshead pin 100. A process mounting hole is machined on the notch plane 130, and the insert 3 is fixed to the notch plane 130 through the process mounting hole, which is specifically a threaded hole. The insert 3 is fixed to the notch plane 130 by fasteners. Please refer to... Figure 5 As shown, the insert 3 is an incomplete cylindrical structure, and its height is less than or equal to the depth at the notch plane 130 of the eccentric crosshead pin 100. An adjustment shim can also be provided between the insert 3 and the notch plane 130 of the eccentric crosshead pin 100. The height of the insert 3 can be adjusted by setting the adjustment shim so that the use requirements of the insert 3 can be met by adding shims after the insert 3 is worn, thus avoiding frequent replacement of the insert 3.

[0046] Further, step two specifically involves: clamping one end of the eccentric crosshead pin 100, turning the outer diameter to a preset length, finishing the weight-reducing hole 110 at the second end, and machining the locating pin hole and threaded hole at the second end. Since the bottom of the weight-reducing hole 110 is uneven after boring, a milling and turning center is used to finish-machine the weight-reducing hole 110, i.e., finish-turning the inner wall of the weight-reducing hole 110 and milling the bottom wall of the weight-reducing hole 110. Then, clamp the second end of the eccentric crosshead pin 100 and turn the remaining portion of the outer diameter. Similarly, finish-machine the weight-reducing hole 110 at the first end, and machine the locating pin hole and threaded hole at the first end. The top plate 4 is positioned and installed with the eccentric crosshead pin 100 through the locating pin hole and threaded hole. Both the first and second ends have two locating pin holes and threaded holes, which are staggered. The top plate 4 is positioned with the eccentric crosshead pin 100 through two locating pins and fixed with two bolts. Please refer to... Figure 6 As shown, the top plate 4 has a center hole 41. The surface of the center hole 41 is hardened and then precision ground to ensure high precision of the center 20 angle and improve durability. The center hole 41 is used to mate with the center 20 of the grinding machine and polishing machine. This arrangement ensures stability during high-precision grinding and polishing processes. In addition, the top plate 4 is designed with a stepped structure. Its large end fits against the end of the eccentric crosshead pin 100, and its small end mates with the inner wall hole of the weight reduction hole 110 to provide support for the eccentric crosshead pin 100. Since the sidewall of the weight reduction hole 110 is precision machined, the fit with the small end of the top plate 4 is more precise, ensuring stability during subsequent grinding and polishing processes.

[0047] Specifically, when performing external turning at the first clamping end, the preset length is determined according to actual needs. In this embodiment, the external diameter of the first clamping end is turned to near the chuck jaws. When clamping the second end of the eccentric crosshead pin 100, since the second end of the eccentric crosshead pin 100 has already been turned, the chuck jaws are corrected based on the already machined external diameter to eliminate the accuracy error caused by the secondary clamping, ensuring that the two turning operations are performed according to the same datum, thus reducing accuracy error. The method of correcting the chuck jaws based on the already machined external diameter is prior art in this field and will not be described again here.

[0048] Further, please refer to Figure 4As shown, the counterweight bar 1 has annular grooves 11 at both ends, and sealing rings (not shown in the figure) are installed in the annular grooves 11. The sealing rings abut against the wall of the eccentric hole 120. By setting the annular grooves 11 and installing the sealing rings, the counterweight bar 1 is prevented from shaking in the eccentric hole 120 during processing, which would affect the dynamic balance. The two ends of the counterweight bar 1 are fixedly connected to limit plates by bolts. The limit plates fit against the counterweight bar 1, and part of the limit plates is pressed against the bottom wall of the weight reduction hole 110. By installing two limit plates, the axial movement of the counterweight bar 1 is limited, which prevents the axial movement of the counterweight bar 1 during processing, which would cause local circular runout and surface accuracy deviation. The total weight of the counterweight bar 1, the two sealing rings, the two limit plates 12 and the bolts is determined after the insert 3 and the two top plates 4 are installed on the eccentric crosshead pin 100. It is ensured that the axis of rotational inertia coincides with the axis of rotation during processing. Specifically, the total weight of the counterweight bar 1, the two sealing rings, the two limit plates 12 and the bolts can be obtained through simulation or experimentation.

[0049] Furthermore, such as Figure 3 As shown, after assembling the counterweight 1, limit baffle 12, insert 3, and top plate 4 onto the eccentric crosshead pin 100, the eccentric crosshead pin 100 is clamped onto the grinding machine, so that the two centers 20 of the grinding machine respectively engage with the two center holes 41 of the top plate 4. The eccentric crosshead pin 100 is rotated and its outer diameter is ground by the chuck 10 and transmission rod 30 of the grinding machine. Before the formal grinding of the eccentric crosshead pin 100, a trial grinding is performed at a fixed point, and the circular runout at the trial grinding position is measured. If the runout does not meet the requirements, the counterweight is adjusted or the pin is re-clamped. Formal grinding is then performed only after the runout meets the requirements, thus ensuring that the runout and surface accuracy after grinding meet the process requirements. Similarly, after grinding, the eccentric crosshead pin 100 is polished in the same way until the surface quality of the outer diameter of the eccentric crosshead pin 100 meets the product requirements. The specific process is not detailed here.

[0050] This invention provides an eccentric crosshead pin 100, specifically an eccentric crosshead pin 100 used in marine methanol engines. The eccentric crosshead pin is manufactured using the manufacturing process described in this embodiment to ensure that its runout and surface quality meet the quality requirements.

[0051] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. The manufacturing process of the eccentric crosshead pin, characterized in that, The process includes the following steps: Step 1: On a horizontal boring machine, axially position the eccentric crosshead pin (100) and lock it radially. Machin the holes on the two end faces of the eccentric crosshead pin (100) and machine the notch plane (130) of the eccentric crosshead pin (100). Step 2: Vertically clamp one end of the eccentric crosshead pin (100) on the milling center and turn the outer diameter. Then clamp the other end of the workpiece and turn the outer diameter. Step 3: Fix the eccentric crosshead pin (100) on the rotary table of the vertical boring machine, finish machine the notch plane (130), and machine the hole on the circumference of the eccentric crosshead pin (100); Step 4: Install a counterweight (1) in the eccentric hole (120) of the eccentric crosshead pin (100), fix the insert (3) at the notch plane (130), and install top plates (4) at both ends of the eccentric crosshead pin (100). Step 5: The two centers (20) of the grinding machine are respectively pressed against the center holes (41) of the two top plates (4), and the eccentric crosshead pin (100) is rotated by the chuck (10) and transmission rod (30) of the grinding machine to grind the eccentric crosshead pin (100). Step 6: Place the two tips (20) of the polishing machine against the tip holes (41) of the two top plates (4) respectively, and drive the eccentric crosshead pin (100) to rotate through the chuck (10) and transmission rod (30) of the polishing machine to polish the eccentric crosshead pin (100).

2. The manufacturing process of the eccentric crosshead pin according to claim 1, characterized in that, The first process is as follows: the weight reduction hole (110) and the eccentric hole (120) on the two end faces of the eccentric crosshead pin (100) are machined, the process mounting hole is machined on the notch plane (130), and the insert (3) is fixed at the notch plane (130) through the process mounting hole.

3. The manufacturing process of the eccentric crosshead pin according to claim 1, characterized in that, The second step is as follows: clamp the first end of the eccentric crosshead pin (100), turn the outer circle to the preset length, finish machine the weight reduction hole (110) at the second end, and machine the positioning pin hole and threaded hole at the second end; clamp the second end of the eccentric crosshead pin (100), turn the remaining part of the outer circle, finish machine the weight reduction hole (110) at the first end, and machine the positioning pin hole and threaded hole at the first end; the top plate (4) is positioned and installed with the eccentric crosshead pin (100) through the positioning pin hole and the threaded hole.

4. The manufacturing process of the eccentric crosshead pin according to claim 3, characterized in that, When clamping the second end of the eccentric crosshead pin (100), the jaws are aligned according to the machined outer diameter.

5. The manufacturing process of the eccentric crosshead pin according to claim 3, characterized in that, The counterweight bar (1) has annular grooves (11) at both ends, and a sealing ring is installed in the annular groove (11). The sealing ring abuts against the wall of the eccentric hole (120).

6. The manufacturing process of the eccentric crosshead pin according to claim 5, characterized in that, The two ends of the counterweight bar (1) are fixedly connected to the limiting baffle (12) by bolts. The limiting baffle (12) is attached to the two ends of the counterweight bar (1), and part of the limiting baffle (12) is attached to the bottom wall of the weight reduction hole (110).

7. The manufacturing process of the eccentric crosshead pin according to claim 6, characterized in that, The total weight of the counterweight (1), the two sealing rings, the two limiting baffles (12) and the bolt is determined after the insert (3) and the two top plates (4) are installed onto the eccentric crosshead pin (100).

8. The manufacturing process of the eccentric crosshead pin according to claim 1, characterized in that, An adjusting shim is also provided between the insert (3) and the notch plane (130) of the eccentric crosshead pin (100).

9. The manufacturing process of the eccentric crosshead pin according to claim 1, characterized in that, Before grinding the eccentric crosshead pin (100), the eccentric crosshead pin (100) is tested at a fixed point and the circular runout at the test point is measured.

10. An eccentric crosshead pin, characterized in that, It is manufactured using the manufacturing process described in any one of claims 1-9 for the eccentric crosshead pin.

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