CN100581695C - Method for processing special-shaped top circle of piston - Google Patents

Abstract

The invention discloses a processing method of a piston irregular excircle, which relates to a piston and provides the processing method of the piston irregular excircle. Two or three turning tools are selected according to the cross-section shape of an irregular excircle piston; with a rotary encoder, turning tools are precisely positioned on a piston processing machine tool; with a normal irregular excircle piston, namely, a standard unit, the turning tools are cut at the same time; a processing parameter is set, and the processing parameter mainly comprises the main shaft speed of the piston processing machine tool, the equation of the piston irregular excircle, etc.; according to the set processing parameter, numeric control programming is made, the interpolated point trace, the feed amount and the processing delay time of the turning tools are calculated, so as to generate the numeric control process code of each turning tool and form the cross-distributed interpolated trace; the numeric control process code is operated, and the turning tools are processed together; after the turning tools are processed together with a surface-shape measuring transducer, the irregular excircle piston is on-site detected; the detected result is performed with data processing; if the detected result is satisfactory, processing is finished; if the detected result is unsatisfactory, the processing is compensated.

Description

A processing method for a special-shaped outer circle of a piston

technical field

The invention relates to a piston, in particular to a method for processing the special-shaped outer circle of the piston by using two or more turning tools.

Background technique

The working principle of the internal combustion engine is that the gas burns rapidly in the cylinder to push the piston to do work, so the piston is a key component of the internal combustion engine, and its performance affects the working ability of the entire system. With the rapid development of the internal combustion engine industry, based on the research on the thermal stress distribution of the piston and the fluid dynamics between the piston and the cylinder liner, in order to pursue the goals of high speed, high efficiency, low consumption, and low noise, the design of the piston has also been proposed. Come higher demands.

The outer circle of the new piston is no longer a simple cylindrical surface, but designed into a specific shape line. From the piston head, ring land, pin hole to skirt, its cross-sectional shape and size are gradually changing. There are cylindrical surface, Conical surface, ellipse, asymmetric ellipse or variable ellipse, etc., are a group of complex three-dimensional graphics, called special-shaped excircles. (referring to Chinese patent CN03124808.X) the turning of special-shaped outer circle is the difficulty in piston manufacture. Compared with grinding and other processing methods, due to the high processing efficiency and processing accuracy of turning processing, turning is used for large-scale processing of special-shaped outer circles of pistons (see literature: 2, Sun Yongqiang, Feng Zhijing, Zhao Guangmu. Domestic pistons Current status of special-shaped cylindrical turning technology. Mechanical Engineer, 2002, 3: 7-9).

Since the early 1990s, my country has made rapid progress in the research and application of piston CNC turning technology, and various forms of CNC piston lathes have emerged. However, due to the increasingly complex design of the piston and the higher and higher requirements for the processing accuracy, smoothness and processing efficiency of the special-shaped outer circle, new challenges are constantly posed to the manufacturing technology of the piston.

When the piston special-shaped outer circle is CNC turned, the turning tool is driven by the micro-feed mechanism. The performance of the micro-feed mechanism, such as response frequency, linear working stroke range, micro-feed resolution and control accuracy, seriously affects the machining accuracy. The smoothness and processing efficiency are mainly determined by the spindle speed. At present, the spindle speed range used in domestic piston processing is generally 1000-1500rpm, and the piston lathe can still maintain good performance when the spindle speed reaches 3000rpm. At the same time, the processing efficiency and the surface finish of the workpiece can be effectively improved by increasing the spindle speed. However, higher requirements are put forward for the performance of the micro-feed mechanism. It is urgent to further develop a micro-feed mechanism with high frequency response, high resolution, high precision, and large stroke. However, the current micro-feed mechanism is relatively Technology lags behind, and technology development still takes a long time.

Contents of the invention

The object of the present invention is to provide a processing method for the special-shaped outer circle of the piston in order to solve the problem that the performance of the micro-feed mechanism is too high due to the increase of the spindle speed.

The technical scheme of the invention is to use at least two turning tools to process the special-shaped outer circle of the piston.

The present invention comprises the following steps:

1) Select 2 or 3 turning tools according to the cross-sectional shape of the special-shaped outer circle piston;

2) Use the rotary encoder to precisely position the turning tool on the piston processing machine tool;

3) Simultaneous tool setting of the turning tool by using the standard special-shaped outer circle piston, that is, the standard part;

4) Set the processing parameters, the processing parameters mainly include the spindle speed of the piston processing machine tool, the piston special-shaped outer circle equation, etc.;

5) According to the set processing parameters, carry out NC programming, calculate the interpolation point trajectory, feed rate and processing delay time of the turning tool (that is, the delay time of turning tool feed), and then generate the NC machining code of each turning tool, Form the interpolation trajectory of the cross distribution;

6) Run the CNC machining code to realize the joint machining of turning tools;

7) Use the surface shape measurement sensor to perform in-position detection on the special-shaped outer circle piston after the joint processing of the turning tool;

8) Perform data processing on the test results. If the surface shape accuracy of the special-shaped outer circle piston meets the requirements, the processing is completed; if the surface shape accuracy of the special-shaped outer circle piston does not meet the requirements, a compensation processing program is generated to perform compensation processing.

The invention solves the problem of high requirements on the performance of the micro-feed mechanism caused by increasing the spindle speed by using 2 or 3 turning tools to jointly process the special-shaped outer circle of the piston. Under the condition of mechanism performance, the spindle speed can be effectively increased, and at the same time, the number of compensation machining can be reduced by in-position detection of the workpiece, the machining accuracy can be guaranteed, and the machining efficiency and surface finish of the piston can be improved at the same time.

Description of drawings

Fig. 1 is a schematic diagram of the basic processing principle of the embodiment of the present invention.

Fig. 2 is a schematic diagram of interpolation of two turning tools according to the embodiment of the present invention.

Fig. 3 is a distribution diagram of interpolation points of two turning tools according to the embodiment of the present invention.

Fig. 4 is a schematic diagram of the interpolation motion of two turning tools during machining according to the embodiment of the present invention.

Detailed ways

The following embodiments will further illustrate the present invention in conjunction with the accompanying drawings.

The codes of the main parts in Figures 1 to 4 are given below:

1 top, 2 micro-feed mechanism, 3 turning tool, 4 tool holder, 5 special-shaped outer circle piston, 6 machine tool table, 7 spindle, 8 chute, 9 sensor, 10 rotary encoder, 11 insertion of turning tool on the left Distribution of interpolation points, distribution of interpolation points of the turning tool on the right of 12.

Fig. 1 is a schematic diagram of the basic processing principle of the embodiment of the present invention. The special-shaped outer circle piston 5 is installed on the main shaft 7, and the upper part is supported by the top 1, and the piston 5 rotates at a high speed with the top 1 and the main shaft 7 during processing. The machine tool table 6 is located outside the main shaft 7 and has a circular structure. The tool rest 4 is installed on the workbench 6, and can move up and down with the workbench 6 during the processing. There is a chute 8 on the workbench 6, and the tool holder 4 can move along the chute 8. At the same time, a rotary encoder 10 is installed on the workbench 6 to precisely adjust the position of the micro-feed mechanism 2 . The micro-feed mechanism 2 is fixed on the tool holder 4, and the position can be adjusted by means of a rotary encoder 10. During processing, the micro-feed mechanism 2 can drive the turning tool 3 to perform reciprocating motion.

The specific processing steps are given below.

First, the number of turning tools is reasonably selected according to the cross-sectional shape of the special-shaped outer circle piston. Since the piston in this embodiment has a symmetrical structure along the major axis and the minor axis, two turning tools are selected to process the piston.

Fig. 2 shows the schematic diagram of the double-knife interpolation of the embodiment of the present invention. The micro-feed mechanism 2 is fixed on the machine table 6. The round piston is the standard part, and the two turning tools 3 are tool-set at the same time; next, the processing parameters are set, mainly including the spindle speed, the piston special-shaped outer circle equation, etc.

Secondly, according to the set processing parameters, carry out NC programming, calculate the interpolation point trajectory, feed amount and processing delay time (that is, the delay time of the turning tool feed) of the two turning tools 2, and then generate the NC machining of each tool The code forms the interpolation trajectory of the cross distribution, and the distribution diagram of the interpolation points of the two turning tools is shown in Figure 3. The distribution of interpolation point trajectories 11 and 12 of the two knives is a cross distribution.

Finally, run the CNC machining code to realize the joint machining of the two turning tools of the piston. Fig. 4 shows the schematic diagram of the interpolation motion of two turning tools in the processing of the embodiment of the present invention. After one processing is completed, the sensor 9 is used to perform in-position detection on the processed results and perform data processing on the detection results to generate a compensation processing program. Perform compensation processing.

Claims (1)

1. the processing method of an irregular excircle of piston is characterized in that may further comprise the steps:

1) selects 2 or 3 lathe tool according to the cross sectional shape of irregular excircle piston;

2) utilize rotary encoder on the piston machining tool, accurately to locate lathe tool;

3) utilizing standard irregular excircle piston is that standard component carries out the while tool setting to above-mentioned each lathe tool;

4) set machined parameters, machined parameters mainly comprises the speed of mainshaft, the irregular excircle of piston equation of piston machining tool;

5) according to the machined parameters that configures, carry out numerical control programming, calculate the time delay of interpolated point track, the amount of feeding and the lathe tool feeding of lathe tool, and then generate each lathe tool numerical control machining code, form the interpolation track of cross-distribution;

6) operation numerical control machining code, the realization lathe tool is processed jointly;

7) utilize the irregular excircle piston after sensor is processed jointly to lathe tool to carry out detection on the throne;

8) testing result is carried out data and handle,, then machine if irregular excircle piston surface figure accuracy meets the requirements; If irregular excircle piston surface figure accuracy is undesirable, then generate the compensation procedure, compensate processing.

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