CN109317937B - Improved aluminum piston machining method - Google Patents

Abstract

The invention discloses an improved processing method for an aluminum piston. The processing method includes the following steps: (1) in the process of finishing the skirt part, the top surface positioning surface is simultaneously refined; (2) the top surface positioning surface 27 and the head outer circle 9 are used to locate the fine boring pin hole 8, and at this time The verticality error between the axis of the pin hole and the axis of the skirt has been determined; (3) Finally, the top surface 7 is finished, that is, the processing of the aluminum piston is completed. In the improved processing method of the present invention, the skirt part and the top surface positioning surface are processed by one-time clamping with the same positioning datum; The shortening of the reference conversion chain during the machining process (only related to the finishing process of the skirt part and the fine boring pin hole process) is beneficial to reduce the perpendicularity error between the axis of the pin hole and the axis of the skirt part.

Description

An Improved Method for Machining Aluminium Pistons

technical field

The invention relates to the field of machining technology, in particular to an improved machining technology for an aluminum piston.

Background technique

The perpendicularity error between the axis of the pin hole of the aluminum piston pin and the axis of the skirt is an important and difficult to control position error in the machining of the aluminum piston. one.

In the commonly used machining process of aluminum pistons, due to the multiple datum conversion (inconsistent datum) errors in the pin hole and skirt during the machining process, the datum conversion chain is long (compared with the finishing process of the skirt and the finishing process of the top surface). and the fine boring pin hole process), which makes it difficult to control the perpendicularity error between the axis of the aluminum piston pin hole and the axis of the skirt.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide an improved processing method for an aluminum piston.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is an improved processing method for an aluminum piston, comprising the following steps:

(1) In the process of finishing the skirt part, the positioning surface of the top surface is finished at the same time;

(2) Use the top surface locating surface 27 and the outer circle 9 of the head to locate the fine boring pin hole 8, and the perpendicularity error between the axis of the pin hole and the axis of the skirt has been determined;

(3) Finally, the top surface 7 is refined, that is, the processing of the aluminum piston is completed.

Preferably, in step (1), after one positioning and clamping, the processing of the skirt 6 and the processing of the top surface positioning surface 27 are completed, and the top surface positioning surface 27 is an annular plane perpendicular to the axis of the piston skirt.

As a further preference, the axis of the piston skirt is the axis of rotation of the piston.

The processing sequence of the aluminum piston of the present invention is: fine turning skirt → fine boring pin hole → fine turning top surface.

The beneficial effects of the present invention are:

After the improved processing method of the present invention is adopted, the skirt part and the top surface positioning surface are processed by one clamping with the same positioning reference, and the fine boring pin hole is positioned with the top surface positioning surface and the outer circle of the head, so that the pin hole and the skirt part are In the process of machining, the reference conversion chain is shortened (only related to the finishing process of the skirt and the fine boring of the pin hole), which is beneficial to reduce the perpendicularity error between the axis of the pin hole and the axis of the skirt.

Description of drawings

The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

FIG. 1 is a schematic diagram of an aluminum piston and various parts thereof according to an embodiment of the present invention.

FIG. 2 is a method for positioning the outer circle of the finishing head and the profile of the finishing skirt in the prior art.

Fig. 3 is a common positioning method of the top surface of the fine turning in the prior art.

FIG. 4 is the shape of the top surface of the aluminum piston after the top surface of the prior art is finished.

FIG. 5 is a schematic diagram of the positioning of the fine boring aluminum piston pin hole in the prior art.

FIG. 6 is a schematic diagram of a finishing skirt and a top surface positioning surface according to an embodiment of the present invention.

7 is a schematic diagram of a process of fine boring an aluminum piston pin hole with a top surface positioning surface as a positioning reference according to an embodiment of the present invention.

Marks in Figure 1 to Figure 7: 1- End face of spigot, 2- Inner chamfer of spigot, 3- Inner side of spigot, 4- Ejector hole, 5- Head, 6- Skirt, 7- Top surface, 8- Pin hole, 9-head outer circle, 10-ring groove, 11-pin hole axis, 12-skirt axis, 17-machined top surface, 27-top surface positioning surface, F1-finishing top surface clamping Force, F2-Fine boring pin hole clamping force.

Detailed ways

Figure 1 is a piston made of aluminum, which is an integral part composed of a head 5 and a skirt 6. The middle of the piston is provided with a through hole - a pin hole 8 in the radial direction. There is a ring groove 10 . The relevant dimensional parameters are as follows: the distance from the pin hole axis 11 to the top surface 7 of the piston blank is 62mm (the top surface is not processed), after finishing the top surface, the distance from the pin hole axis to the top surface of the piston is 60±0.03mm, and the piston head The outer diameter of the portion 5 is φ90±0.02 mm.

1. Processing methods of aluminum pistons commonly used at present

In the commonly used machining process of aluminum piston, the main processing benchmarks are (see Figure 1): the end face of the spigot 1, the inner chamfer of the spigot 2, the inner side of the spigot 3, and the thimble hole 4.

The perpendicularity error between the axis 11 of the aluminum piston pin hole and the axis 12 of the skirt is a comprehensive reflection of the positioning reference error and machining error of multiple processes in the finishing section, except for the end face of the stop 1, the inner chamfer of the stop 2 and the thimble hole 4. In addition to the position error between the two, the processes that affect this error mainly include: finishing the skirt 6 (the skirt is generally convex and elliptical after finishing), the top surface of the finishing 7, and the fine boring pin hole 8.

The usual processing sequence is: fine turning skirt 6 → fine turning top surface 7 → fine boring pin hole 8, see Figure 1.

In the process of finishing the skirt 6, the inner chamfer 2 and the thimble hole 4 are used for positioning, and the thimble hole 4 clamps (tightens) the piston at the same time, as shown in Figure 2, the surface of the skirt after finishing is generally In the process of finishing the top surface of the turning, the end face 1 of the spigot and the inner side surface 3 of the spigot are used for positioning, F1 is the clamping force, as shown in Figure 3, and the top surface 17 after processing is shown in Figure 4; In the process of fine boring pin hole 8, the top surface 7 and the outer circle 9 of the head are used for positioning, and F2 is the clamping force, as shown in Figure 5.

The measurement reference for the perpendicularity error between the axis 11 of the piston pin hole and the axis 12 of the skirt is the axis 12 of the skirt. The axis of the skirt needs to be determined by the surface of the skirt, and the positioning reference of the surface of the skirt is the inner chamfer 2 of the spigot and the thimble Hole 4; on the other hand, the top surface 7 of the piston is positioned by the end face 1 (excluding the thimble hole 4), which is inconsistent with the positioning reference of the machining skirt; the positioning reference of the fine boring pin hole process is after the piston is finished turning The top surface 7 and the outer circle 9 of the head (before machining the outer circle of the head, the annular groove 10 on the outer surface of the head must be machined), which are also inconsistent with the positioning reference of the machining skirt. Therefore, if the turning process is carried out according to the usual method, the pin hole and the skirt will have multiple reference conversion (reference non-conformity) errors during the machining process, and the reference conversion chain will be longer (compared with the finishing process of the skirt part, the finishing process of the top surface and the process of finishing the top surface). It is related to the fine boring pin hole process), which makes it difficult to control the perpendicularity error between the axis 11 of the piston pin hole and the axis 12 of the skirt.

2. Improved processing method of aluminum piston

An improved aluminum piston machining process is as follows:

At the same time of finishing the skirt part 6 process, the finishing top surface positioning surface 27 is added, that is, after one positioning and clamping, the processing of the skirt part 6 and the processing of the top surface positioning surface 27 are completed. The top positioning surface 27 is an annular plane perpendicular to the axis 12 of the piston skirt (ie, the axis of rotation of the piston), the distance between the top positioning surface 27 and the pin hole axis 11 is 60.5±0.03, and the inner diameter of the top positioning surface 27 is φ60 , see Figure 6. Next, use the top surface locating surface 27 and the head outer circle 9 to locate the fine boring pin hole 8 , see FIG. 7 . After that, the top surface 7 is refined again, see FIG. 3 . The relevant processing sequence is: fine turning skirt 6 (including top surface positioning surface 27 ) → fine boring pin hole 8 → fine turning top surface 7 .

When the above process is used to process the aluminum piston, the perpendicularity error of the pin hole axis 11 and the skirt axis 12 is only related to the finishing process of the skirt part 6 and the fine boring pin hole 8, but has nothing to do with the finishing process of the top surface 7. Therefore, it is easier to ensure the perpendicularity error between the axis 11 of the pin hole and the axis 12 of the skirt during the machining process.

After adopting the improved aluminum piston machining process of this embodiment, the skirt 6 and the top surface positioning surface 27 are processed by one clamping with the same positioning reference, and the fine boring pin hole 8 uses the top surface positioning surface 27 and the head The outer circle 9 is positioned, so that the reference conversion chain of the pin hole and the skirt is shortened during the machining process (only related to the finishing process of the skirt and the fine boring pin hole process), which is beneficial to reduce the perpendicularity of the pin hole axis and the skirt axis. error.

The embodiments of the present invention described above do not limit the protection scope of the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (3)

1. An improved processing method for an aluminum piston, comprising the following steps: (1) In the process of finishing the skirt part, at the same time finishing the positioning surface of the top surface; (2) Use the top surface positioning surface (27) and the head outer circle (9) to locate the fine boring pin hole (8), at this time, the perpendicularity error between the axis of the pin hole and the axis of the skirt has been determined; (3) Finally, the top surface (7) is finished, that is, the processing of the aluminum piston is completed. 2. The processing method for an aluminum piston according to claim 1, wherein in step (1), after one positioning and clamping, the processing of the skirt (6) and the processing of the top surface positioning surface (27) are completed , and the top surface positioning surface (27) is an annular plane perpendicular to the axis of the piston skirt. 3 . The processing method for an aluminum piston according to claim 2 , wherein the axis of the piston skirt is the axis of rotation of the piston. 4 .

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