A process for solving the problem of off-center boring of high carbon steel cracking connecting rod bushing

Abstract

The present invention discloses a process for solving the problem of eccentric boring of high carbon steel cracking connecting rod bushing hole. The connecting rod comprises a connecting rod body and a connecting rod cover installed at the end of the connecting rod body. The connecting rod body and the connecting rod cover are connected by a plurality of bolts installed on the side. A large-head hole is provided between the connecting rod body and the connecting rod cover, and a small-head hole is provided at the other end of the connecting rod body. During the processing, the small-head hole is positioned by a positioning device. The positioning device of the present invention is an elastic chamfered expansion sleeve. The chamfered expansion sleeve is a cylinder with a through hole in the middle and two prisms protruding symmetrically on the outside of the side wall. One end of the chamfered expansion sleeve is designed with chamfered edges, and the other end is symmetrically provided with two slots. Therefore, the present invention can solve the problem of eccentric boring of high carbon steel cracking connecting rod bushing hole to ensure the processing of the connecting rod.

Description

Technical Field

[0001] The invention relates to the technical field of automobile engine connecting rod processing, in particular to a process method for solving the problem of eccentric boring of a high carbon steel cracked connecting rod bushing hole. Background Art

[0002] The connecting rod bushing is composed of a backing and a lining. Since the bushing is a thin-walled part, it is affected by the thickness error of the connecting rod bushing, the bushing joint or oil hole structure, and the contact rate between the bushing and the connecting rod hole after being pressed into the bushing. The inner diameter size and shape error of the small end of the connecting rod after being pressed into the bushing can reach 0.2mm. The big end hole of the high-carbon steel cracked connecting rod generally produces a plastic deformation of about 0.05mm after cracking. In mass production, unreasonable connecting rod processing process or positioning method may cause uneven boring of the connecting rod bushing, that is, the coaxiality of the connecting rod small end bushing hole and the connecting rod small end bottom hole after fine boring exceeds 0.2mm, and even the bushing may be partially bored, seriously affecting the function of the connecting rod. Summary of the invention

[0003] The purpose of the present invention is to provide a process method for solving the problem of off-center boring of high carbon steel cracked connecting rod bushing holes, so as to solve the problem of off-center boring of high carbon steel cracked connecting rod bushing holes in the prior art, so that the coaxiality of the connecting rod small head bushing hole and the connecting rod small head bottom hole after fine boring does not exceed 0.1mm.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] The invention discloses a process for solving the problem of eccentric boring of high carbon steel cracking connecting rod bushing hole, wherein the connecting rod comprises a connecting rod body and a connecting rod cover installed at the end of the connecting rod body, the connecting rod body and the connecting rod cover are connected by a plurality of bolts installed on the side, a large head hole is opened between the connecting rod body and the connecting rod cover, and a small head hole is opened at the other end of the connecting rod body, and the process comprises the following steps:

[0006] (1) First, rough grinding the two end surfaces of the connecting rod;

[0007] (2) using the rough-ground outer shape of the connecting rod for positioning, rough boring the large head hole and the small head hole, leaving a semi-finishing allowance for the large head hole, and machining the small head hole to the size before pressing the bushing;

[0008] (3) processing the connecting rod bolt pressure bearing surface and bolt hole;

[0009] (4) carving stress grooves into the large-head holes, cracking and assembling;

[0010] (5) positioning and processing the large head hole with the small head hole to eliminate the shape error of the connecting rod after cracking;

[0011] (6) Pressing a bushing into the small head hole and fine grinding the two end surfaces of the connecting rod;

[0012] (7) Precision boring the large-head hole and the small-head hole, using the end face of the connecting rod to position and limit three degrees of freedom, using the large-head hole to position and limit two degrees of freedom, and using the small-head hole to position and limit one degree of freedom; wherein the small-head hole is positioned using an elastic chamfered expansion sleeve.

[0013] Furthermore, in step (2), the center distance tolerance between the large-head hole and the small-head hole is 0.03 mm.

[0014] Furthermore, in step (5), the diameter tolerance of the large-head hole is 0.03 mm, and the center distance tolerance of the large-head hole and the small-head hole is 0.03 mm.

[0015] Furthermore, in step (7), the large head hole is positioned by a cylindrical pin.

[0016] The present invention discloses a positioning device for solving the problem of eccentric boring of a connecting rod bushing hole in a high carbon steel cracking process. The positioning device is an elastic chamfered expansion sleeve, which is a cylinder with a through hole in the middle and two prisms protruding symmetrically on the outside of the side wall. One end of the chamfered expansion sleeve is designed with a chamfered edge and the other end is symmetrically provided with two grooves.

[0017] Furthermore, the two prisms and the two slots are arranged crosswise.

[0018] Furthermore, the top surface of the prism in the circumferential direction is an arc with the center of the chamfered expansion sleeve as the center, and the top surfaces of the two prisms in the circumferential direction are cocircular.

[0019] Furthermore, the diameter of the circle where the top surface of the prism is located is 17.3±0.03 mm, and the outer diameter of the chamfered expansion sleeve is 16.3 mm.

[0020] Furthermore, the chord length corresponding to the arc of the top surface of the prism in the circumferential direction is 3 mm.

[0021] Compared with the prior art, the beneficial technical effects of the present invention are:

[0022] The process method for solving the problem of off-center boring of a high-carbon steel cracked connecting rod bushing hole of the present invention can solve the problem of off-center boring of a high-carbon steel cracked connecting rod bushing hole, and is easy to operate, effectively reduces costs, and has reliable product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below in conjunction with the accompanying drawings.

[0024] Figure 1 The schematic diagram of the process for solving the problem of off-center boring of high carbon steel cracked connecting rod bushing hole according to the present invention;

[0025] Figure 2 The schematic diagram of the process for solving the problem of off-center boring of high carbon steel cracked connecting rod bushing hole according to the present invention;

[0026] Figure 3 It is a top view structural schematic diagram of a positioning device for solving the problem of off-boring of a high carbon steel cracked connecting rod bushing hole according to the present invention;

[0027] Figure 4 The present invention is a schematic diagram of the three-dimensional structure of a positioning device for solving the problem of off-boring of a high carbon steel cracked connecting rod bushing hole.

[0028] Explanation of the reference numerals: 1. connecting rod body; 2. connecting rod cover; 3. small head hole; 4. large head hole; 5. chamfered expansion sleeve; 51. slotting. DETAILED DESCRIPTION

[0029] Example 1

[0030] like Figure 1 , Figure 2 As shown, a process for solving the problem of eccentric boring of high carbon steel cracking connecting rod bushing hole described in Example 1 of the present invention, the connecting rod comprises a connecting rod body 1 and a connecting rod cover 2 installed at the end of the connecting rod body 1, the connecting rod body 1 and the connecting rod cover 2 are connected by a plurality of bolts installed on the side, a large head hole 4 is opened between the connecting rod body 1 and the connecting rod cover 2, and a small head hole 3 is opened at the other end of the connecting rod body 1, which comprises the following steps:

[0031] (1) First, rough grinding the two end surfaces of the connecting rod;

[0032] (2) Using the rough-ground outer shape of the connecting rod for positioning, the large head hole 4 and the small head hole 3 are roughly bored, a semi-finishing allowance is left for the large head hole 4, and the small head hole 3 is machined to the size before the bushing is pressed;

[0033] (3) processing the connecting rod bolt pressure bearing surface and bolt hole;

[0034] (4) carving stress grooves on the large head hole 4, cracking and assembling;

[0035] (5) positioning and processing the large head hole 4 with the small head hole 3 to eliminate the shape error of the connecting rod after cracking;

[0036] (6) Press a bushing into the small head hole 3 and finely grind the two end surfaces of the connecting rod;

[0037] (7) Precision boring the large head hole 4 and the small head hole 3, using the end surface of the connecting rod to position and limit three degrees of freedom, using the large head hole 4 to position and limit two degrees of freedom, and using the small head hole 3 to position and limit one degree of freedom; wherein the small head hole 3 is positioned by an elastic chamfering sleeve 5.

[0038] Specifically, in step (2), the center distance tolerance between the large head hole 4 and the small head hole 3 is 0.03 mm.

[0039] Specifically, in step (5), the diameter tolerance of the large-head hole 4 is 0.03 mm, and the center distance tolerance between the large-head hole 4 and the small-head hole 3 is 0.03 mm.

[0040] Specifically, in step (7), the large head hole 4 is positioned by a cylindrical pin.

[0041] Example 2

[0042] like Figure 3 , Figure 4 As shown, a positioning device for solving the problem of eccentric boring of a connecting rod bushing hole in high carbon steel cracking is described in Example 2 of the present invention. The positioning device is an elastic chamfered expansion sleeve 5. The chamfered expansion sleeve 5 is a cylinder with a through hole in the middle and two prisms protruding symmetrically on the outside of the side wall. One end of the chamfered expansion sleeve 5 is designed with a chamfered edge and the other end has two symmetrical grooves 51.

[0043] Specifically, the two prisms and the two slots 51 are cross-arranged.

[0044] Specifically, the top surface of the prism in the circumferential direction is an arc with the center of the chamfered expansion sleeve 5 as the center, and the top surfaces of the two prisms in the circumferential direction are cocircular.

[0045] Specifically, the diameter of the circle where the top surface of the prism is located is 17.3±0.03 mm, and the outer diameter of the chamfered expansion sleeve 5 is 16.3 mm.

[0046] Specifically, the chord length corresponding to the arc of the top surface of the prism in the circumferential direction is 3 mm. Figure 3 Preferably, α is 120.9°.

[0047] The process method for solving the problem of off-center boring of a high-carbon steel cracked connecting rod bushing hole of the present invention can solve the problem of off-center boring of a high-carbon steel cracked connecting rod bushing hole, and is easy to operate, effectively reduces costs, and has reliable product quality.

[0048] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A process for solving the problem of eccentric boring of high carbon steel cracking connecting rod bushing hole, the connecting rod comprises a connecting rod body and a connecting rod cover installed at the end of the connecting rod body, the connecting rod body and the connecting rod cover are connected by a plurality of bolts installed on the side, a large head hole is opened between the connecting rod body and the connecting rod cover, and a small head hole is opened at the other end of the connecting rod body, characterized in that: It includes the following steps: (1) First, rough grinding the two end surfaces of the connecting rod; (2) using the rough-ground outer shape of the connecting rod for positioning, rough boring the large head hole and the small head hole, leaving a semi-finishing allowance for the large head hole, and machining the small head hole to the size before pressing the bushing; (3) processing the connecting rod bolt pressure bearing surface and bolt hole; (4) carving stress grooves into the large-head holes, cracking and assembling; (5) positioning and processing the large head hole with the small head hole to eliminate the shape error of the connecting rod after cracking; (6) Pressing a bushing into the small head hole and fine grinding the two end surfaces of the connecting rod; (7) precision boring the large head hole and the small head hole, limiting three degrees of freedom by positioning the end face of the connecting rod, limiting two degrees of freedom by positioning the large head hole, and limiting one degree of freedom by positioning the small head hole; wherein the small head hole is positioned by an elastic chamfering sleeve; The chamfered expansion sleeve is a cylinder with a through hole in the middle and two prisms protruding symmetrically on the outside of the side walls. One end of the chamfered expansion sleeve is designed with a chamfered edge and the other end has two symmetrical grooves. The two prisms and the two grooves are arranged crosswise. The circumferential top surface of the prism is an arc with the center of the chamfered expansion sleeve as the center, and the circumferential top surfaces of the two prisms are cocircular.

2. The process for solving the problem of uneven boring of high carbon steel cracked connecting rod bushing according to claim 1 is characterized in that: In step (2), the center distance tolerance between the large-head hole and the small-head hole is 0.03 mm.

3. The process for solving the problem of uneven boring of high carbon steel cracked connecting rod bushing according to claim 2 is characterized in that: In step (5), the diameter tolerance of the large-head hole is 0.03 mm, and the center distance tolerance of the large-head hole and the small-head hole is 0.03 mm.

4. The process for solving the problem of uneven boring of high carbon steel cracked connecting rod bushing according to claim 1 is characterized in that: In step (7), the large head hole is positioned by a cylindrical pin.

5. The process for solving the problem of uneven boring of high carbon steel cracked connecting rod bushing according to claim 1 is characterized in that: The diameter of the circle where the top surface of the prism is located is 17.3±0.03 mm, and the outer diameter of the chamfered expansion sleeve is 16.3 mm.

6. The process for solving the problem of uneven boring of high carbon steel cracked connecting rod bushing according to claim 1 is characterized in that: The chord length corresponding to the arc of the top surface of the prism in the circumferential direction is 3 mm.

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