阅读说明：本技术 一种干式螺杆压缩机的机体油槽加工方法 (Machining method for engine body oil groove of dry type screw compressor ) 是由 洪洲 周杰 俞鑫 王刚 堵俊杰 于 2021-06-24 设计创作，主要内容包括：本发明提供一种干式螺杆压缩机的机体油槽加工方法,其可以降低刀具损伤的概率,提高加工效率。本专利技术方案中,通过槽初始圆进行完整圆槽削切,然后逐渐调大非同心上下首尾相接半圆半径,进行螺旋渐开循环切削,最后一个槽终结圆为完整圆,加工完成后,退刀回起始点,完成对机体油槽的加工。(The invention provides a machining method for an oil groove of a machine body of a dry type screw compressor, which can reduce the probability of damage of a cutter and improve the machining efficiency. Among this patent technical scheme, carry out complete circular slot through groove initial circle and cut, then transfer big non-concentric upper and lower end-to-end connection semicircle radius gradually, carry out the spiral and open gradually the circulation cutting, last groove final circle is complete circle, and processing is accomplished the back, and the initial point is returned to the tool withdrawal, accomplishes the processing to organism oil groove.)

1. A machining method for an oil groove of a machine body of a dry type screw compressor comprises the following steps:

s1: acquiring a target groove radius R and a total machining allowance W of an oil groove of a machine body;

s2: acquiring the depth of the oil groove of the machine body as the cutter depth De;

s3: confirming the position of the center O of the oil groove;

it is characterized by also comprising the following steps:

s4: calculating the total machining times N according to the total machining allowance W and the back cutting allowance Q;

NQ≤W≤（N+1）Q

wherein Q is the back cutting depth, which is the cutting depth of the milling cutter in the radius direction of each circle processed by the milling cutter when a groove is processed, and is equal to the numerical value of the radius of the upper semicircle and the radius of the lower semicircle of the central track of the milling cutter which need to be changed each time;

s5: on a machine body workpiece to be machined, finding the position of the circle center O, and performing feed machining by taking the circle center O as a machining starting point and the tool depth De as a tool depth;

the feed distance L is the initial radius r0 of the initial circle of the groove minus the radius d/2 of the cutter;

r0 = R - W；

L= r0 - d/2；

s6: keeping the cutter depth De by taking the circle center O as the circle center and the end point of the cutter feeding groove as the starting point of the circumference, and processing the initial circle of the groove;

s7: the allowance of the subsequent groove is processed in a mode that the upper semicircle and the lower semicircle are connected end to end;

sequentially giving out the upper semicircle radius rT to be processed_iRadius rB of the lower semicircle_i；

rT_i= r0 + Q/2+（i -1）×Q；

rB_i=rT_i+ Q/2；

Wherein i is the processing frequency, and i is not more than N;

s8: step S7 is executed in a loop until i = N;

processing a whole circle with the radius as the target radius R of the groove by taking the circle center O as the circle center to serve as a groove finishing circle;

and after the groove ending circle is machined, the milling cutter is withdrawn, and the milling cutter returns to the position of the circle center O along the radius direction.

2. The oil groove processing method for the machine body of the dry type screw compressor as claimed in claim 1, wherein: before step S5 is performed, a confirmation step is performed;

the confirmation step includes: and virtually processing the initial circle of the groove by taking the circle center O as a processing starting point, setting the depth of the cutter as 0 and the radius as r 0.

3. The oil groove processing method for the machine body of the dry type screw compressor as claimed in claim 1, wherein: in step S7, the upper semicircle and the lower semicircle are divided into a diameter where the tool feeding slot is located.

4. The oil groove processing method for the machine body of the dry type screw compressor as claimed in claim 1, wherein: the back draft Q is a positive number.

Technical Field

The invention relates to the technical field of dry type screw compressor processing, in particular to a method for processing an oil groove of a machine body of a dry type screw compressor.

Background

In the operation process of the dry screw compressor, lubricating oil flows back through an oil groove in the bearing hole, and partial compressed air leaked into the bearing hole is drained, so that the compressed air in the rotor cavity is isolated from the lubricating oil, and zero oil content of the compressed air is realized.

The oil groove has large machining allowance, so that the oil groove cannot be machined in place at one time. The existing machining method of the oil groove of the engine body is to machine the groove layer by adopting a three-edge milling cutter and a circle expanding method. Fig. 1 is a diagram showing a tool path of a milling cutter according to a conventional machining method; fig. 2 is a simulation diagram of a machining track of a conventional machining method, in which a machined oil groove 1 of a machine body is provided with a feed groove 2 and a withdrawal groove 3, and a feed track groove 4 and a withdrawal track groove 5 formed by frequent feeding and withdrawal; as can be seen from fig. 1 and 2, the conventional method requires frequent tool advance and retreat for machining the groove, and the instantaneous load and impact of the tool are relatively large during the tool advance and retreat, which easily causes the blade to be broken and further damages the body structure of the tool; meanwhile, due to frequent cutter feeding and retracting, the cutting efficiency of the processing is affected, and the processing time is prolonged.

Disclosure of Invention

In order to solve the problems that a cutter is easy to damage and the machining efficiency is low in the existing machining method of the oil groove of the machine body of the dry type screw compressor, the invention provides the machining method of the oil groove of the machine body of the dry type screw compressor, which can reduce the probability of damage of the cutter and improve the machining efficiency.

The technical scheme of the invention is as follows: a machining method for an oil groove of a machine body of a dry type screw compressor comprises the following steps:

s1: acquiring a target groove radius R and a total machining allowance W of an oil groove of a machine body;

s2: acquiring the depth of the oil groove of the machine body as the cutter depth De;

s3: confirming the position of the center O of the oil groove;

it is characterized by also comprising the following steps:

s4: calculating the total machining times N according to the total machining allowance W and the back cutting allowance Q;

NQ≤W≤（N+1）Q

wherein Q is the back cutting depth, which is the cutting depth of the milling cutter in the radius direction of each circle processed by the milling cutter when a groove is processed, and is equal to the numerical value of the radius of the upper semicircle and the radius of the lower semicircle of the central track of the milling cutter which need to be changed each time;

s5: on a machine body workpiece to be machined, finding the position of the circle center O, and performing feed machining by taking the circle center O as a machining starting point and the tool depth De as a tool depth;

the feed distance L is the initial radius r0 of the initial circle of the groove minus the radius d/2 of the cutter;

r0 = R - W；

L= r0 - d/2；

s6: keeping the cutter depth De by taking the circle center O as the circle center and the end point of the cutter feeding groove as the starting point of the circumference, and processing the initial circle of the groove;

s7: the allowance of the subsequent groove is processed in a mode that the upper semicircle and the lower semicircle are connected end to end;

sequentially giving out the upper semicircle radius rT to be processed_iRadius rB of the lower semicircle_i；

rT_i= r0 + Q/2+（i -1）×Q；

rB_i=rT_i+ Q/2；

Wherein i is the processing frequency, and i is not more than N;

s8: step S7 is executed in a loop until i = N;

processing a whole circle with the radius as the target radius R of the groove by taking the circle center O as the circle center to serve as a groove finishing circle;

and after the groove ending circle is machined, the milling cutter is withdrawn, and the milling cutter returns to the position of the circle center O along the radius direction.

It is further characterized in that:

before step S5 is performed, a confirmation step is performed;

the confirmation step includes: virtually processing the initial circle of the groove by taking the circle center O as a processing starting point, setting the depth of a cutter to be 0 and the radius to be r 0;

in step S7, the upper semicircle and the lower semicircle are divided into a diameter where the tool feeding slot is located;

the back draft Q is a positive number.

The invention provides a processing method of an oil groove of a machine body of a dry type screw compressor, which comprises the steps of carrying out complete circular groove cutting through a groove initial circle, then gradually increasing the radius of non-concentric upper, lower, end and tail connected semi-circles, carrying out spiral involute circular cutting, enabling the last groove end circle to be a complete circle, and withdrawing a cutter to return to the initial point after the processing is finished; the whole method is simple in structure and higher in running speed, and the processing efficiency is improved; according to the technical scheme, each cutter processing track unit is formed in a mode that the upper semicircle and the lower semicircle are connected end to end, the final formed processing track is approximate to a spiral involute, the cutting amount is constant in the circular processing process, the damage to the cutter is small, and the probability of damage to the cutter is reduced; in the technical scheme, frequent feeding and retracting are not needed, only the action of feeding and retracting transversely is carried out at the beginning and the end of the oil groove of the machine body, and the cutting arc of each circular groove is longer, so that the impact force of the cutter at the cutting moment is greatly reduced, and the damage probability of the cutter is further reduced.

Drawings

Fig. 1 is a tool path diagram of a milling cutter of a conventional machining method;

FIG. 2 is a simulation diagram of a machining trajectory of a conventional machining method;

FIG. 3 is a simulation diagram of a machining trajectory of the machining method of the present patent;

FIG. 4 is a schematic view showing the connection of the upper and lower semicircles in the processing path;

fig. 5 shows the state of the machining blade after 50 machine body workpieces to be machined are machined according to the technical scheme of the patent;

fig. 6 is an example of the machine body oil groove processed based on the technical scheme of the patent.

Detailed Description

As shown in fig. 3 to 6, the method for processing an oil groove of a machine body of a dry type screw compressor of the present invention includes the following steps:

s1: and acquiring a target groove radius R and a total machining allowance W of the oil groove 1 of the machine body.

S2: the depth of the oil groove 1 of the machine body is obtained as the cutter depth De.

S3: on a machine body workpiece to be machined, the position of the center O of the oil groove is confirmed, and the center O is the groove center of the machine body oil groove 1.

S4: calculating the total machining times N according to the total machining allowance W and the back cutting allowance Q;

NQ≤W≤（N+1）Q

wherein Q is the back cutting depth, which is the cutting depth of the milling cutter in the radius direction of each circle processed by the milling cutter when a groove is processed, and is equal to the numerical value of the radius of the upper semicircle and the radius of the lower semicircle of the central track of the milling cutter which need to be changed each time;

and setting the specific numerical value of Q according to the working condition of the processing.

Before formal processing, a confirmation procedure is carried out;

the confirmation step includes: taking the circle center O as a processing starting point, setting the depth of a cutter to be 0, setting the radius to be r0, and processing an initial circle 1-1 of a virtual processing groove;

the state of the cutter is confirmed by trial cutting through the operation confirmation process, so that the problem that the workpiece of the machine body to be processed is not damaged due to the existence of the cutter is avoided.

S5: on a machine body workpiece to be machined, finding the position of a circle center O, and performing feed machining by taking the circle center O as a machining starting point and the cutter depth De as a cutter-entering depth;

the feed distance L is the initial radius r0 of the initial circle of the groove minus the radius d/2 of the cutter;

r0 = R - W；

L= r0 - d/2；

if a machine body oil groove 1 with W =20 mm and 120 mm of outer circle is machined, r0 is 100 mm;

in this embodiment, the depth De of the blade is 1mm, i.e., the depth of the groove is 1 mm.

S6: keeping the depth De of the cutter by taking the circle center O as the circle center and the end point of the cutter feeding groove as the starting point of the circumference, and processing a groove initial circle 1-1;

in this embodiment, the back draft Q is a positive number, that is, a concentric circle with the smallest radius is used as the initial groove circle 1-1.

S7: the allowance of the subsequent groove is processed in a mode that the upper semicircle and the lower semicircle are connected end to end,

sequentially giving out the upper semicircle radius rT to be processed_iRadius rB of the lower semicircle_i；

rT_i= r0 + Q/2+（i -1）×Q；

rB_i=rT_i+ Q/2；

Wherein i is the processing times and is a positive integer; i is less than or equal to N;

the upper semicircle and the lower semicircle are divided by the diameter of the knife feeding groove 8.

After the initial groove circle 1-1 is machined, the circular groove of the upper semicircle is machined, i is assigned from 1, and the milling cutter receives the first radius rT of the upper semicircle₁After the 1 st upper semicircle is processed, the 1 st lower semicircle connected with the head of the 1 st upper semicircle is processed to give a radius rB₁. And after the 1 st lower semicircle is machined, continuing to provide the 2 nd upper semicircle connected with the tail part of the first upper semicircle, and sequentially assigning values to machine the allowance of the subsequent groove.

The upper semi-circle and the lower semi-circle are connected in a mode, all the upper semi-circles are concentric circles, and all the lower semi-circles are concentric circles, referring to a figure 4 of a drawing of the specification; the circle center O1 of the upper semicircle is positioned at the position Q/4 of the circle center O, and the circle center O2 of the lower semicircle is positioned at the position Q/4 of the circle center O; o1 and O2 are a distance of Q/2; the terminal point of the ith upper semicircle is connected with the starting point of the ith lower semicircle, and the terminal point of the ith lower semicircle is connected with the starting point of the (i + 1) upper semicircles; the processing track formed by the upper semicircle and the lower semicircle which are connected end to end and have gradually increased radiuses is approximate to a spiral involute.

S8: step S7 is executed in a loop until i = N;

after the i-1 th semicircle is processed, the last full circle is processed without processing the semicircle, and groove type sealing is carried out on the oil groove 1 of the engine body; processing a whole circle with the radius as the target radius R of the groove by taking the circle center O as the circle center to be used as a groove finishing circle 1-2;

after finishing the processing of the groove finishing circle 1-2, withdrawing the milling cutter, and returning to the position of the circle center O along the radius direction to finally obtain the oil groove 1 of the machine body; as shown in fig. 3, the relief groove 7 and the entry groove 8 in this patent are located on the same diameter.

During specific implementation, based on the existing numerical control machining technology and a numerical control machine tool control system, machining is carried out, the rotating speed and the length compensation of the cutter are set firstly, and a corresponding coordinate system is set. All the parts are processed by a groove processing program in a numerical control machine tool control systemUpper semi-circle radius rT_iRadius rB of the lower semicircle_iStoring, firstly processing a tank initial circle 1-1, and then respectively processing an upper semicircle and a lower semicircle which are connected end to end; before processing a semicircle at each time, the radius of the upper semicircle or the lower semicircle processed at this time is discharged, and whether the radius rT exists or not is judged before processing_i、rB_iIf the current time exists, the processing is continued; if the end circle does not exist, the last whole circular groove end circle 1-2 is machined, the cutter is withdrawn finally, and the milling cutter returns to the position of the circle center O along the radius direction.

The simulated track formed after the processing based on the technical scheme of the patent is shown in figure 3, the processing track of the oil groove 1 of the engine body is a continuous involute circle formed by splicing upper and lower non-concentric semicircles one by one, and the distance between the circles is constant; compare with the frequent advance and retreat sword of orbit among the prior art, among this patent technical scheme, because avoided frequently advancing and retreat sword, so avoided the cutter body vibrations too big and the collapse sword problem that leads to take place. As shown in FIG. 4, the machine body oil groove 1 processed by the technical scheme of the patent only has a transverse feed groove 8 and a transverse withdrawal groove 7 at the beginning and the end of the groove, and the cutting arc is longer, so that the impact force of the cutter at the cutting moment is greatly reduced, and the probability of cutter damage is reduced. As shown in fig. 5, according to the technical scheme of the present patent, after 50 machine body workpieces to be processed are processed, only the normal blade is worn, the cutter body is intact, and the blade screw does not loosen.

In the aspect of machining efficiency, due to the fact that continuous cutting is adopted in the technical scheme, frequent cutter feeding and retracting are not needed in the middle, machining time can be saved by about 20% -30% in a single process, and working hours and machining cost of parts are reduced. Taking the engine oil groove 1 shown in fig. 3 as an example, the processing time in the prior art is 21 minutes, the processing time in the technical scheme of the patent is 13 minutes and 49 seconds, and the processing efficiency is improved by about 30%. As shown in fig. 6, for the machining effect of the machine body oil groove 1 machined based on the technical scheme of the patent, the machining lines of the groove body are relatively uniform, and no local extremely serious jolting knife lines exist.