Processing method of eight-shaped assembled face ball hole connecting rod

Abstract

The application discloses a processing method of an eight-shaped combined assembling ball hole connecting rod and belongs to the technical field of connecting rod machining. The processing method comprises the following steps: sequentially opening a straight hole and an assembling hole on an aluminum blank connecting rod to obtain a semi-finished connecting rod; the semi-finished connecting rod is divided into a connecting rod body and a connecting rod cover along a plane which is coplanar with the diameter of the straight hole and perpendicular to the axis of the assembling hole; an arc surface is milled on the division surface of the connecting rod body; the connecting rod body and the connecting rod cover are combined and assembled by means of the assembling hole through a fastener to obtain a combined and assembled connecting rod; a ball hole is milled on the position of the straight hole of the combined and assembled connecting rod to obtain a finished connecting rod; and the finished connecting rod which meets the quality inspection standards is screened as the ball hole connecting rod. The application provides a new eight-shaped combined assembling surface, the ball hole can be restored to the shape during processing by adjusting the fastener to a specified torque, the gap between the ball hole and the ball shaft surface is uniform at this time, the rotation is smooth, the installation is simple, and the service life of the part is long.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of connecting rod machining, and particularly relates to a processing method of an eight-shaped combined surface ball hole connecting rod. BACKGROUND

[0002] At present, the ball hole of a ball connecting rod is processed by first opening a hole in the parting surface of the ball hole, then cutting the integrally cast connecting rod into two halves, and then machining the ball hole after the two halves of the connecting rod are fastened together with screws. When the ball connecting rod is used, the screws are first removed, the two halves of the connecting rod are separated, the ball shaft is installed into the ball hole, and then the two halves of the connecting rod are fastened together again.

[0003] According to the prior art, since there is a gap between the ball shaft and the ball hole, and there is also a gap between the screw and the screw hole for fastening the two halves of the connecting rod, the ball hole formed by the screw connecting the two halves of the connecting rod has a problem of insufficient matching precision with the ball shaft, which affects the service life of the connecting rod. SUMMARY

[0004] The application aims to provide a processing method of an eight-shaped combined surface ball hole connecting rod to solve the above problems in the prior art.

[0005] Technical scheme: A processing method of an eight-shaped combined surface ball hole connecting rod, comprising the following steps:

[0006] A processing method of an eight-shaped combined surface ball hole connecting rod, comprising the following steps:

[0007] Step 1: sequentially opening a straight hole and an assembly hole in an aluminum blank connecting rod to obtain a semi-finished connecting rod;

[0008] Step 2: dividing the semi-finished connecting rod into a connecting rod body and a connecting rod cover along a plane coplanar with the diameter of the straight hole and perpendicular to the axis of the assembly hole;

[0009] Step 3: milling an arc surface on the division surface of the connecting rod body;

[0010] Step 4: combining the connecting rod body and the connecting rod cover by means of the assembly hole through a fastener to obtain a combined connecting rod;

[0011] Step 5: milling a ball hole at the position of the straight hole of the combined connecting rod to obtain a finished connecting rod;

[0012] Step 6: screening the finished connecting rod that meets the quality inspection standards as a ball hole connecting rod.

[0013] Further, the milling of the arc surface on the division surface of the connecting rod body comprises:

[0014] Step 31: fixing the division surface of the connecting rod body to a horizontal position by using a jig;

[0015] Step 32: selecting an end mill with an effective milling diameter Φ greater than the length 2A of the division surface;

[0016] Step 33: adjust the end mill vertically arranged to rotate alpha degrees around the connecting rod body on the two assembly hole circle center connecting line;

[0017] Step 34: adjust the end mill lowest point to the effective milling height of the connecting rod body H;

[0018] Step 35: drive the end mill along the direction perpendicular to the connecting rod body on the two assembly hole circle center connecting line and through the midpoint of the circle center connecting line, so that the split surface is milled into an arc surface.

[0019] Further, the angle alpha of the end mill adjustment in the step 33 is obtained from formula one

[0020] As a result,

[0021] Wherein, 0.030mm≤H≤0.040mm, 2A∈(27mm, 30mm, 33mm), the value of H is positively related to A, and the effective milling diameter Φ of the end mill is greater than 12A.

[0022] Further, the torsion of the fastener for assembling the connecting rod body and the connecting rod cover in the step 4 is 300N·cm to 350N·cm.

[0023] Further, the setting diameter of the straight hole in the step 1 is R, and R∈(9.0mm, 13.5mm, 16.0mm).

[0024] Further, the setting diameter of the ball hole in the step 5 is X, and X∈(12.700mm, 15.875mm, 19.050mm).

[0025] Further, the standard of the quality inspection finished connecting rod in the step 3 is that whether the height difference h of the eight-shaped assembled surface of the finished connecting rod satisfies 0.035mm≤h≤0.055mm; if yes, the quality inspection is up to standard, otherwise, the quality inspection is not up to standard.

[0026] Beneficial effects: the application provides a new eight-shaped assembled surface, before processing the ball hole, the integral structure of the connecting rod body and the connecting rod cover is restored by using a screw, the fastening torque causes the warping deformation before the arc surface processing, after the processing is completed, the fastening screw is removed to restore the original state of the warping deformation before the arc surface, at this time, the interference is generated when the spherical surface of the ball hole is assembled, the ball tile tightly holds the spherical surface shaft, there is no play gap, as long as the fastening member is adjusted to the torque during the processing, the ball hole can restore the shape during the processing, at this time, the gap between the ball hole and the spherical shaft surface is uniform, the rotation is smooth, the installation is simple, and the service life of the part is long. BRIEF DESCRIPTION OF DRAWINGS

[0027] Fig. 1 It is the processing step diagram of the application.

[0028] Fig. 2 is a schematic diagram of the machining steps of the present application.

[0029] Fig. 3 is a schematic diagram of the derivation of formula one in the present application.

[0030] The reference signs are: 1, aluminum blank connecting rod; 2, semi-finished connecting rod; 3, assembly hole; 4, straight hole; 5, connecting rod body; 6, connecting rod cover; 7, split surface; 8, arc surface; 9, assembled connecting rod; 10, fastener; 11, finished connecting rod; 12, ball hole; 13, eight-shaped assembly surface; 14, ball hole connecting rod. DETAILED DESCRIPTION

[0031] In the following description, a large number of specific details are given to provide a more thorough understanding of the present application. However, it is obvious to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, some technical features known in the art are not described in order not to obscure the present application.

[0032] As shown in Figs. 1-3 , a processing method of an eight-shaped assembly surface ball hole connecting rod, comprising the following steps:

[0033] Step 1: sequentially open straight hole 4 and assembly hole 3 on aluminum blank connecting rod 1 to obtain semi-finished connecting rod 2;

[0034] Step 2: split semi-finished connecting rod 2 into connecting rod body 5 and connecting rod cover 6 along a plane coplanar with the diameter of straight hole 4 and perpendicular to the axis of assembly hole 3;

[0035] Step 3: mill arc surface on split surface 7 of connecting rod body 5;

[0036] Step 4: use assembly hole 3 to assemble connecting rod body 5 and connecting rod cover 6 by fastener 10 to obtain assembled connecting rod 9;

[0037] Step 5: mill ball hole 12 on the position of straight hole 4 of assembled connecting rod 9 to obtain finished connecting rod 11;

[0038] Step 6: screen finished connecting rod 11 that meets the quality inspection standards as ball hole connecting rod 14.

[0039] Step 3 specifically includes:

[0040] Step 31: use a jig to fix split surface 7 of connecting rod body 5 to a horizontal position;

[0041] Step 32: select an end mill with an effective milling diameter Φ greater than the length 2A of split surface 7;

[0042] Step 33: adjust the end mill vertically set around the center line of the two assembly holes 3 on the connecting rod body 5 to rotate α degrees; the oblique setting of the end mill needs to be achieved by adjusting the angle of the milling machine spindle.

[0043] Step 34: adjust the effective milling height of the lowest point of the end mill to the connecting rod body 5 to H;

[0044] Step 35: drive the end mill to feed along the direction perpendicular to the center line of the two assembly holes on the connecting rod body 5 and passing through the midpoint of the center line, to obtain the connecting rod body 5 with the split surface 7 milled as a cambered surface 8.

[0045] The angle α of the end mill adjustment in step 33 is determined by formula one

[0046] The result is

[0047] Wherein, 0.030mm≤H≤0.040mm, 2A∈27mm, 30mm, 33mm, H is positively correlated with A, and the effective milling diameter Φ of the end mill is greater than 12A. When the ratio of the effective milling diameter Φ of the end mill to the length 2A of the split surface 7 is small, if you want to have a suitable effective milling height H, you need a larger installation angle of the end mill, which requires a larger angle improvement of the milling machine spindle. From the transmission design point of view, the design difficulty is larger; when the ratio of the effective milling diameter Φ of the end mill to the length 2A of the split surface 7 is small, if you want to have a suitable effective milling height H, the installation angle of the end mill is small, which makes it difficult to achieve the slight angle adjustment of the milling machine spindle. Setting the effective diameter Φ of the end mill to be greater than 12A is to make the oblique end mill have a suitable effective milling height H, and the oblique angle of the end mill is within the oblique range of the milling machine spindle, so as to reduce the adjustment difficulty of the milling machine spindle.

[0048] The torsion of the fastener 10 combined with the connecting rod body 5 and the connecting rod cover 6 in step 4 is 300N·cm to 350N·cm. The torsion is obtained by experiment. When the rotating torque of the M4 thread of this material is greater than 350N·cm, the screw hole will be deformed. When it is less than 300N·cm, the deformation of the connecting rod cannot achieve the ideal effect.

[0049] The diameter of the straight hole 4 in step 1 is R, R∈9.0mm, 13.5mm, 16.0mm. Among them, the diameter of the straight hole 4 is positively correlated with the thickness of the connecting rod.

[0050] The diameter of the ball hole 12 in step 5 is X, X∈12.700mm, 15.875mm, 19.050mm. After the connecting rod 9 is assembled, the ball hole 12 is processed at the center of the contact surface between the connecting rod body 5 and the connecting rod cover 6 (so that the ball hole is symmetrical along the contact surface), and the connecting rod product 11 is obtained through rough turning and fine boring.

[0051] The standard of the quality inspection of the finished connecting rod 11 in step 3 is to determine whether the height difference h of the eight-shaped assembling surface 13 on the finished connecting rod 11 meets 0.035mm≤h≤0.055mm; if yes, the quality inspection is up to the standard, otherwise, the quality inspection is not up to the standard.

[0052] The selected range of h is an empirical value, if the selected value of h is greater than 0.055mm, the assembled connecting rod connected by the fastener has stress concentration, which is easy to crack the connecting rod, if the selected value of h is less than 0.035mm, the assembled connecting rod connected by the fastener has insufficient deformation, and the assembling effect is poor.

[0053] Specifically, when the diameter X of the middle ball hole 12 is 12.700mm, the height difference h of the eight-shaped assembling surface 13 is preferably 0.03±0.005mm;

[0054] When the diameter X of the middle ball hole 12 is 15.875mm, the height difference h of the eight-shaped assembling surface 13 is preferably 0.04±0.005mm;

[0055] When the diameter X of the middle ball hole 12 is 19.050mm, the height difference h of the eight-shaped assembling surface 13 is preferably 0.05±0.005mm.

[0056] In particular, in the above processing process, only three sizes of the diameter of the ball hole 12 are selected, because after the industrial revolution, the textile industry developed rapidly in the United Kingdom, and with the development of sewing machine technology, the size design of the key components of the sewing machine gradually formed an industry standard based on the British standard.

[0057] The preferred embodiments of the application are described in detail above in combination with the drawings, but the application is not limited to the specific details in the above embodiments, and various equivalent transformations of the technical solutions of the application can be made within the scope of the technical concept of the application, and these equivalent transformations all belong to the protection scope of the application.

Claims

1. A method of machining an eight-point closed die ball socket connecting rod, characterized by, It comprises the following steps: Step 1: sequentially opening straight holes (4) and assembly holes (3) on an aluminum blank connecting rod (1) to obtain a semi-finished connecting rod (2); Step 2: dividing the semi-finished connecting rod (2) into a connecting rod body (5) and a connecting rod cover (6) along a plane coplanar with the diameter of the straight hole (4) and perpendicular to the axis of the assembly hole (3); Step 3: milling an arc surface on the split surface (7) of the connecting rod body (5); Step 4: assembling the connecting rod body (5) and the connecting rod cover (6) through fasteners (10) using the assembly holes (3) to obtain an assembled connecting rod (9); Step 5: milling a ball hole (12) on the straight hole (4) of the assembled connecting rod (9) to obtain a finished connecting rod (11); Step 6: screening the finished connecting rod (11) that meets the quality inspection standards as a ball hole connecting rod (14); Wherein, the milling of the arc surface (8) on the split surface (7) of the connecting rod body (5) comprises: Step 31: fixing the split surface (7) of the connecting rod body (5) to a horizontal position using a jig; Step 32: selecting an end mill with an effective milling diameter Φ greater than 2A of the length of the split surface (7); Step 33: adjusting the end mill vertically arranged to rotate α degrees around the center line of the two assembly holes (3) on the connecting rod body (5); Step 34: adjusting the lowest point of the end mill to an effective milling height H of the connecting rod body (5); Step 35: driving the end mill to feed in a direction perpendicular to the center line of the two assembly holes on the connecting rod body (5) and passing through the midpoint of the center line to obtain a connecting rod body (5) with the split surface (7) milled as an arc surface (8); Wherein, the angle α of the end mill adjustment in step 33 is determined by formula one As a result, Wherein, 0.030mm≤H≤0.040mm, 2A∈(27mm, 30mm, 33mm), the value of H is positively correlated with A, and the effective milling diameter Φ of the end mill is greater than 12A; Wherein, the torque of the fastener (10) for assembling the connecting rod body (5) and the connecting rod cover (6) in step 4 is 300N·cm to 350N·cm.

2. The method of claim 1 wherein, The diameter of the straight hole (4) in step 1 is R, and R∈(9.0mm, 13.5mm, 16.0mm).

3. The method of claim 2, wherein the method further comprises: The diameter of the ball hole (12) in step 5 is X, and X∈(12.700mm, 15.875mm, 19.050mm).

4. A method of machining an eight-shaped, built-up, face-bored connecting rod according to any one of claims 1-3, characterized in that, The standard for the finished connecting rod (11) in step 3 is: judging whether the height difference h of the eight-shaped assembled surface (13) on the finished connecting rod (11) meets 0.035mm≤h≤0.055mm; if yes, the quality inspection is up to standard, otherwise, the quality inspection is not up to standard.

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