Processing method for locating pin hole of connecting rod of diesel engine

Abstract

Provided is a method for processing locating pin holes for connecting rods of diesel engines, belonging to the technical field of connecting rod processing. The present invention proposes a two-stage pin hole processing for processing pin holes on connecting rods. Specifically: when processing the pin holes in the semi-finished state of the rod body and rod cover, i.e., the first-stage processing, a certain margin is left for processing the pin holes on the premise of meeting the requirements of the later assembly. After the big head hole is precisely bored, the rod body and rod cover are disassembled. During the second-stage processing, the size of the pin hole relative to the center axis and end face of the big head hole is individually calibrated, and then assembled, tested and put into storage. This method not only retains the positioning function of the original locating pin hole, but also meets the requirements of the pin hole design drawings, solving the long-standing difficulty of the pin hole position not meeting the requirements. The design concept is novel, the structure is simple, and it can be quickly promoted to solve similar problems.

Description

Technical Field

[0001] The invention belongs to the technical field of connecting rod processing, and in particular relates to a processing method for a locating pin hole of a connecting rod of a diesel engine. Background Art

[0002] The connecting rod used in a diesel engine consists of two main parts: the rod body and the rod cap. The rod body and rod cap are positioned with a pin and connected with connecting rod bolts and nuts. The connecting rod connects the crankshaft and piston, making it a crucial component of the crankshaft-connecting rod mechanism and crucial for continuous engine operation.

[0003] Among them, the position of the pin hole is particularly important, which determines the roundness of the hole after assembly and directly affects the service life of the connecting rod. The existing processing method of the connecting rod is:

[0004] 1. After milling the upper and lower sides of the connecting rod;

[0005] 2. Saw off and divide it into the rod body and rod cover

[0006] 3. Milling and boring (rod body, rod cover) big head hole, etc.;

[0007] 4. Milling the hard surface, processing bolt holes and pin holes;

[0008] 5. Assembly;

[0009] 6. Fine boring of large head holes

[0010] This method processes the pin holes in a semi-finished state and then fine-machines the grub holes after assembly. However, the drawing requires inspection in the finished state. Therefore, the pin hole position accuracy produced in this way is unlikely to meet the drawing requirements (which require a position accuracy of 0.05 or less). Furthermore, even if the pin hole position accuracy is high in the semi-finished state, the subsequent fine-machining of the grub holes will cause slight deformation of the connecting rod after the rod body and rod cap are disassembled, causing the pin hole's inspection position accuracy to exceed the drawing requirements. Therefore, improvements are necessary. Summary of the Invention

[0011] The technical problem solved by the present invention is to provide a method for processing the locating pin hole of the connecting rod of a diesel engine. The purpose of the present invention is to overcome the shortcomings of the existing technology so that the basic dimensions and form and position tolerances of the connecting rod can meet the requirements of the design drawings whether it is in an assembled state or disassembled into a rod body and a rod cover.

[0012] In order to achieve the above object, the technical solution adopted by the present invention is:

[0013] A method for machining a locating pin hole for a connecting rod of a diesel engine comprises the following steps:

[0014] Step 1): Mill the upper and lower end surfaces A of the connecting rod;

[0015] Step 2): Saw the connecting rod into the rod body and the rod cover;

[0016] Step 3): Rough milling and rough boring of the large head holes on the rod body and rod cap;

[0017] Step 4): Mill the hafnium surface on the rod body and rod cover, and process the bolt holes;

[0018] Step 5): Secondary processing of pin hole:

[0019] 5a) When machining the pin holes of the rod body and rod cap, reduce the size of the pin holes, reserve a margin, and perform rough machining on the pin holes, which is the first-level machining of the pin holes:

[0020] 5b) Connect the shaft and cap together according to the assembly requirements;

[0021] 5c) Fine boring of large head holes;

[0022] 5d) Disassemble the shaft and cap;

[0023] 5e) Using the center axis O and end face A of the finely bored large head hole as reference, re-finish and calibrate the pin holes on the rod body and rod cap to the dimensions required by the drawing. This is secondary processing.

[0024] Step 6): Assemble the shaft and cap together, inspect and put into storage.

[0025] When the drawing requires that the pin hole on the rod is The pin hole on the rod cover is required to be When the position accuracy requirement is 0.05mm:

[0026] In the above step 5a), when the pin hole is processed in the first level, the reduced size of the pin hole on the rod body is The reduced size of the pin hole on the rod cover is

[0027] In step 5e) above, when the pin hole undergoes secondary processing, the dimension L1 of the pin hole from the center axis O of the large head hole in the X and Y directions is made to meet 217.5±0.02mm, and the dimension L2 of the pin hole from the end face A is made to meet 61.5±0.015mm, thus achieving the position accuracy of 0.05mm required by the drawing.

[0028] In the above step 5b), the rod body and the rod cover are connected together by assembling elastic pins and bolts and nuts.

[0029] Furthermore, the elastic pin is provided with an axial through hole inside and an opening on one side.

[0030] Furthermore, the outer diameter of the elastic pin is The length is 35mm.

[0031] The advantages of the present invention compared with the prior art are:

[0032] This solution proposes a two-level pin hole processing for the processing of pin holes on connecting rods. Specifically, when processing the pin holes in the semi-finished state of the rod body and rod cover, that is, the first-level processing, a certain margin is left for the pin holes while meeting the requirements of the later assembly. After the big head hole is precision-bored, the rod body and rod cover are disassembled, and the pin holes are processed in the second level. The dimensions of the pin holes relative to the center axis and end face of the big head hole are individually calibrated, and then assembled, inspected and put into storage. This method not only retains the positioning function of the original positioning pin holes, but also meets the requirements of the pin hole design drawings, solving the long-standing difficulty of the pin hole position not meeting the requirements. The design concept is novel, the structure is simple, and it can be quickly promoted to solve similar problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a front view of the structure of the shaft of the present invention;

[0034] Figure 2 For the present invention Figure 1 Schematic diagram of the C-direction structure;

[0035] Figure 3 For the present invention Figure 1 A magnified schematic diagram of the structure of Part I;

[0036] Figure 4 This is a front view of the structure of the rod cover in the present invention;

[0037] Figure 5 This is a top view of the rod cover structure of the present invention;

[0038] Figure 6 For the present invention Figure 4 A magnified schematic diagram of the structure of part II;

[0039] Figure 7 This is a front view of the structure of the elastic pin in the present invention;

[0040] Figure 8 It is the left side view of the structure of the elastic pin in the present invention. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0042] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0043] See also Figure 1-8 , details the embodiments of the present invention.

[0044] The processing method for the positioning pin hole of the connecting rod of a diesel engine is as follows: Taking a certain model as an example, when the drawing requires that the pin hole 6 on the rod body 1 is The pin hole 6 on the rod cover 2 is required to be When the position accuracy requirement is 0.05mm; see Figure 1-6 As shown, the processing method includes the following steps:

[0045] Step 1): Mill the upper and lower end surfaces A of the connecting rod;

[0046] Step 2): Saw the connecting rod into the rod body 1 and the rod cover 2;

[0047] Step 3): Rough milling and rough boring of the large end hole 3 on the rod body 1 and the rod cover 2;

[0048] Step 4): Milling the hafnium surface 4 on the rod body 1 and the rod cover 2, and processing the bolt holes 5;

[0049] Step 5): Secondary processing of pin hole 6:

[0050] 5a) When machining the pin hole 6 of the shaft 1 and the cap 2, reduce the size of the pin hole 6, reserve a margin, and perform rough machining on the pin hole 6, which is the first-level machining of the pin hole 6:

[0051] In this embodiment, when the pin hole 6 is processed in the first stage, the reduced size of the pin hole 6 on the shaft 1 is The reduced size of the pin hole 6 on the rod cover 2 is

[0052] 5b) Connecting the shaft 1 and the cap 2 together according to assembly requirements;

[0053] In this embodiment, the rod body 1 and the rod cover 2 are connected together by using elastic pins 7 and bolts and nuts. Figure 7 and 8 As shown, the elastic pin 7 is provided with an axial through hole inside and an opening on one side. The outer diameter of the elastic pin 7 is The length is 35mm.

[0054] 5c) Fine boring of the big head hole 3;

[0055] 5d) disassembling the shaft 1 and the cap 2;

[0056] 5e) Using the center axis O and end face A of the finely bored large end hole 3 as reference, re-finish and calibrate the pin holes 6 on the shaft 1 and cap 2 to the dimensions specified in the drawing, which is the secondary machining;

[0057] In this embodiment, when the pin hole 6 undergoes secondary processing, the dimension L1 of the pin hole 6 from the center axis O of the big head hole 3 in the X and Y directions meets 217.5±0.02mm, and the dimension L2 of the pin hole 6 from the end face A meets 61.5±0.015mm, which can achieve the position accuracy of 0.05mm required by the drawing.

[0058] Step 6): Assemble the shaft 1 and the cap 2 together, and inspect and store them.

[0059] The present invention proposes a two-stage pin hole processing for the processing of the pin hole on the connecting rod. Specifically, when processing the pin hole in the semi-finished state of the rod body and rod cover, that is, the first-stage processing, a certain margin is left for the pin hole processing under the premise of meeting the requirements of the later assembly. After the big head hole is precisely bored, the rod body and rod cover are disassembled. During the second-stage processing, the size of the pin hole relative to the center axis and end face of the big head hole is individually corrected, and then assembled, tested and put into storage. This method retains the positioning function of the original positioning pin hole and can meet the requirements of the pin hole design drawings, solving the long-standing difficulty of the pin hole position not meeting the requirements. The design concept is novel, the structure is simple, and it can be quickly promoted to solve similar problems.

[0060] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0061] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for processing a locating pin hole for a connecting rod of a diesel engine, characterized in that: The following steps are involved: Step 1): Mill the upper and lower end surfaces A of the connecting rod; Step 2): sawing the connecting rod into the rod body (1) and the rod cover (2); Step 3): Rough milling and rough boring of the large head hole (3) on the rod body (1) and the rod cover (2); Step 4): milling the hafnium surface (4) on the rod body (1) and the rod cover (2), and processing the bolt holes (5); Step 5): Secondary processing of pin hole (6): 5a) When machining the pin hole (6) of the rod body (1) and the rod cover (2), the size of the pin hole (6) is reduced, a margin is reserved, and the pin hole (6) is rough-machined, which is the first-level machining of the pin hole (6): 5b) connecting the rod body (1) and the rod cover (2) together according to assembly requirements; 5c) Fine boring of the large head hole (3); 5d) disassembling the shaft (1) and the cover (2); 5e) Using the center axis O and end face A of the finely bored large head hole (3) as reference, fine-machine and correct the pin holes (6) on the rod body (1) and rod cover (2) to the dimensions required by the drawing, which is the secondary machining; Step 6): Assemble the shaft (1) and the rod cover (2) together, and inspect and store them.

2. The method for machining a locating pin hole for a connecting rod of a diesel engine according to claim 1, characterized in that: When the drawing requires that the pin hole (6) on the shaft (1) is The pin hole (6) on the rod cover (2) is required to be When the position accuracy requirement is 0.05mm: In the above step 5a), when the pin hole (6) is processed in the first stage, the reduced size of the pin hole (6) on the shaft (1) is The reduced size of the pin hole (6) on the rod cover (2) is In the above step 5e), when the pin hole (6) is subjected to secondary processing, the dimension L1 of the pin hole (6) from the central axis O of the large head hole (3) in the X and Y directions is made to meet 217.5±0.02mm, and the dimension L2 of the pin hole (6) from the end face A is made to meet 61.5±0.015mm, so as to achieve the position accuracy of 0.05mm required by the drawing.

3. The method for machining a locating pin hole for a connecting rod of a diesel engine according to claim 2, characterized in that: In the above step 5b), the rod body (1) and the rod cover (2) are connected together by assembling elastic pins (7) and bolts and nuts.

4. The method for machining a locating pin hole for a connecting rod of a diesel engine according to claim 3, characterized in that: The elastic pin (7) is provided with an axial through hole inside and an opening on one side.

5. The method for machining a locating pin hole for a connecting rod of a diesel engine according to claim 4, characterized in that: The outer diameter of the elastic pin (7) is The length is 35mm.

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