阅读说明：本技术 废气再循环进出水管管口凸径的加工方法 (Method for processing pipe orifice convex diameter of waste gas recirculation water inlet and outlet pipe ) 是由 张新华 惠燕妮 张海宁 韩军 于 2020-03-30 设计创作，主要内容包括：本发明公开了一种废气再循环进出水管管口凸径的加工方法,包括步骤：一、夹持废气再循环进出水管的管身,对成品的环形凸径至管口端的整段管身扩径至成品的环形凸径外径尺寸形成扩口段；二、保持夹持废气再循环进出水管的管身,保留一段长度大于成品的环形凸径轴向长度的所述扩口段,对从保留的所述扩口段至管口端部分进行缩径,保留的所述扩口段形成预留波段；三、保持夹持废气再循环进出水管的管身,对所述预留波段进行轴向挤压至成品的环形凸径的轴向长度完成管口凸径的加工。本发明方法仅进行一次夹持,管口部分不需要夹持后进行轴向加工,加工效率高,尺寸精度好,提高了产品合格率。(The invention discloses a method for processing the convex diameter of a pipe orifice of a waste gas recirculation water inlet and outlet pipe, which comprises the following steps: clamping a pipe body of the waste gas recirculation water inlet and outlet pipe, and expanding the whole section of the pipe body from the annular convex diameter of a finished product to the pipe orifice end to the outer diameter size of the annular convex diameter of the finished product to form an expanded section; keeping a pipe body clamping the waste gas recirculation water inlet and outlet pipe, keeping a section of the flaring section with the length larger than the axial length of the finished annular convex diameter, reducing the diameter from the reserved flaring section to the end part of the pipe end, and forming a reserved waveband by the reserved flaring section; and thirdly, maintaining the pipe body clamping the waste gas recirculation water inlet and outlet pipe, and axially extruding the reserved wave band to the axial length of the annular convex diameter of the finished product to complete the processing of the convex diameter of the pipe orifice. The method only carries out one-time clamping, and the pipe orifice part does not need to be axially processed after being clamped, so that the machining efficiency is high, the dimensional precision is good, and the product percent of pass is improved.)

1. A processing method for the convex diameter of the pipe orifice of a waste gas recirculation water inlet and outlet pipe is characterized by comprising the following steps:

clamping a pipe body of the waste gas recirculation water inlet and outlet pipe, and expanding the whole section of the pipe body from the annular convex diameter of a finished product to the pipe orifice end to the outer diameter size of the annular convex diameter of the finished product to form an expanded section;

step two, keeping a pipe body clamping the waste gas recirculation water inlet and outlet pipe, reserving a flaring section with the length larger than the axial length of the finished annular convex diameter, reducing the diameter from the reserved flaring section to the end part of the pipe end, and forming a reserved waveband by the reserved flaring section;

and step three, maintaining the pipe body clamping the waste gas recirculation water inlet and outlet pipe, and axially extruding the reserved wave band until the axial length of the annular convex diameter of the finished product is reached to complete the processing of the convex diameter of the pipe orifice.

2. The method for processing the pipe orifice convex diameter of the waste gas recirculation water inlet and outlet pipe according to claim 1, wherein the axial length of the reserved wave band is 3-4 mm longer than that of the annular convex diameter of the finished product.

3. The method for processing the pipe orifice convex diameter of the exhaust gas recirculation water inlet/outlet pipe according to claim 1, wherein in the second step of reducing the diameter, the pipe diameter is reduced to the pipe diameter of the clamped pipe body.

4. The method for processing the pipe orifice convex diameter of the exhaust gas recirculation water inlet and outlet pipe according to claim 1, characterized by comprising the fourth step of holding the pipe body of the exhaust gas recirculation water inlet and outlet pipe and necking the end surface of the pipe.

5. The method for processing the pipe orifice convex diameter of the waste gas recirculation water inlet and outlet pipe according to claim 1, wherein the diameter expansion in the first step, the diameter reduction in the second step and the third step are all performed by a punch punching process.

6. The method for processing the pipe orifice convex diameter of the exhaust gas recirculation water inlet/outlet pipe according to claim 4, wherein the necking in the fourth step is performed by a punch punching process.

Technical Field

The invention relates to a method for processing a metal pipe orifice, in particular to a method for processing the convex diameter of a pipe orifice of a waste gas recirculation water inlet and outlet pipe.

Background

The automobile exhaust gas recirculation water inlet and outlet pipe is usually made of a stainless steel thin-wall pipe, the pipe orifice structure of the automobile exhaust gas recirculation water inlet and outlet pipe needs to be processed into the structure shown in figure 1, namely, an annular convex diameter is formed at a position which is about 4.5mm away from the pipe orifice, and the pipe orifice needs to be made into a necking.

The conventional processing of the annular convex diameter of the pipe orifice needs two conditions:

the first clamping end needs to be stably clamped, the phenomenon that materials are not clamped when the materials are subjected to forming opposite force, the materials are moved in a string mode and slip occurs, and the clamping friction force needs to be increased by enough clamping area. The inner cavity of the pipe fitting product is empty, and the pipe fitting is deformed by clamping the outer diameter with single force, so that the method is suitable for the contrary. If the clamping area is insufficient or the length is insufficient, the required forming clamping force needs to be reduced by reducing the forming force; secondly, a forming force is applied to the opposite surface, the forming punch generates a relative extrusion process by means of the forming force and the force for fixing the clamping die end, the middle area of the straight pipe is stressed and expanded to generate deformation, and the required contour shape of the convex-diameter bulge is designed by the profiling size of the die.

The length of the clamping end of the automobile exhaust gas recirculation water inlet and outlet pipe is very short, and the area required by clamping cannot be met. The material crosstalk amount is large, and the problem of insufficient bulge and small outer diameter is easy to occur in the process of forming the annular convex diameter. The prior art is improved, an opening expanding tool is adopted, internal expansion preforming convex-diameter bulging is carried out, and then opposite extrusion forming is carried out, so that forming extrusion force and forming clamping force are reduced, and material movement is avoided. The method can produce qualified products, and the qualified rate can reach more than 90%, but the following problems still exist and need to be continuously improved. The problems include: firstly, the processing efficiency is low, the cost is high, one product needs to be subjected to mouth expanding and extruding operations on two tools, and the operation period is long; secondly, the size and the precision are poor, the requirement of a final product cannot be guaranteed due to the internally expanded profile and shape, secondary stamping is needed, and the secondary positioning processing exists when the internally expanded shape is placed in a die for secondary stamping, so that the size deviation of the final product is caused. And thirdly, the inner expansion positioning reference is the end face of the product, the secondary extrusion positioning is the rear end bending profile of the product, the reference changes, and the length of the material subjected to molding extrusion is different. The size of the extruded material is out of tolerance when the extruded material is too large, and the waveform is small when the extruded material is small.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for processing the convex diameter of the pipe orifice of the waste gas recirculation water inlet and outlet pipe, and aims to solve the problems that the traditional processing method cannot process the pipe orifice, and the internal expansion preforming method needs to carry out clamping twice, has low processing efficiency and has poor product size precision.

The technical scheme of the invention is as follows: a processing method for the convex diameter of the pipe orifice of an exhaust gas recirculation water inlet and outlet pipe comprises the following steps:

clamping a pipe body of the waste gas recirculation water inlet and outlet pipe, and expanding the whole section of the pipe body from the annular convex diameter of a finished product to the pipe orifice end to the outer diameter size of the annular convex diameter of the finished product to form an expanded section;

step two, keeping a pipe body clamping the waste gas recirculation water inlet and outlet pipe, reserving a flaring section with the length larger than the axial length of the finished annular convex diameter, reducing the diameter from the reserved flaring section to the end part of the pipe end, and forming a reserved waveband by the reserved flaring section;

and step three, maintaining the pipe body clamping the waste gas recirculation water inlet and outlet pipe, and axially extruding the reserved wave band until the axial length of the annular convex diameter of the finished product is reached to complete the processing of the convex diameter of the pipe orifice.

Preferably, the axial length of the reserved wave band is 3-4 mm longer than that of the annular convex diameter of the finished product.

And further, reducing the pipe diameter to the pipe diameter of the clamped pipe body in the second diameter reducing step.

And further, the pipe body of the exhaust gas recirculation water inlet and outlet pipe is kept clamped, and the end face of the pipe is necked.

Preferably, the diameter expansion of the first step, the diameter reduction of the second step and the third step are all performed by a punch stamping process.

Preferably, the necking of the fourth step is performed by a punch stamping process.

The technical scheme provided by the invention has the advantages that:

1. the whole machining process only needs one-time clamping, machining benchmarks of multiple steps are unified, and bad products caused by non-unified benchmarks due to multiple clamping can be avoided.

2. In each processing step, the operations of expanding and reducing the diameter of the pipe orifice part are not obviously axially deformed, so that the pipe orifice is not required to be clamped in a large area, only the stable clamping of the pipe body is required to be kept, and the pipe orifice is not required to be clamped in a large area due to the fact that the reserved wave band can be axially stressed during axial compression, so that the operation of clamping in a large area is integrally avoided, the phenomenon that the material is moved due to the fact that the area is too small is avoided, and the size precision is ensured.

3. The processing qualification rate of the product can reach about 98 percent by the method.

4. In the processing method of the prior art, flaring needs 10 seconds, extrusion needs 12 seconds, time waste is caused by product waiting and backlog in the process, the total time of the four steps of the invention is 16 seconds, and the processing time of a single product is shortened by 6 seconds.

5. The method has the advantages that operators only need to charge, start and discharge, the operation flow is simplified, and the operators can carry out work such as product inspection and the like in the time process of equipment operation.

Drawings

FIG. 1 is a schematic structural diagram of a nozzle part of an exhaust gas recirculation water inlet and outlet pipe.

FIG. 2 is a schematic view of the deformation step of the pipe orifice of the method for processing the convex diameter of the pipe orifice of the waste gas recirculation water inlet and outlet pipe.

Fig. 3 is a schematic structural view of a pipe clamping tool.

Fig. 4 is a schematic structural view of an expanding punch.

Fig. 5 is a schematic view of a reducing punch.

Fig. 6 is a schematic view of the structure of an axial extrusion punch.

Fig. 7 is a structural schematic diagram of a pipe orifice end face necking punch.

Detailed Description

The present invention is further described in the following examples, which are intended to be illustrative only and not to be limiting as to the scope of the invention, which is to be given the full breadth of the appended claims and any and all equivalent modifications thereof which would occur to persons skilled in the art upon reading the present specification and which are intended to be within the scope of the present invention as defined in the appended claims.

Referring to fig. 2, the processing method of the pipe orifice convex diameter of the exhaust gas recirculation water inlet and outlet pipe according to the embodiment depends on a four-station punching forming machine, and specifically includes the following steps:

step one, as shown in fig. 3, a pipe body clamping tool is used for clamping a pipe body 2 of an exhaust gas recirculation water inlet and outlet pipe, embedding the pipe body 2 of the exhaust gas recirculation water inlet and outlet pipe into a clamping cavity 3, as shown in fig. 4, an expanding punch is used for expanding the whole section of the pipe body from an annular convex diameter 1 of a finished product to the outer diameter of the annular convex diameter 1 of the finished product to form an expanding section 4;

step two, keeping the pipe body 2 clamping the waste gas recirculation water inlet and outlet pipe, reducing and deforming the flared section 4 formed in the step one by a reducing punch shown in figure 5, wherein the axial length of the reducing deformation is smaller than that of the flared section 4 obtained in the step one, namely, a flared section 4 is reserved, the flared section is called a reserved waveband 5, the pipe diameter of the reserved waveband 5 is the same as that of the annular convex diameter 1 part of a finished product, the axial length of the reserved waveband 5 is 3-4 mm longer than that of the annular convex diameter 1 part of the finished product, and a processing space is reserved for the step three, and the pipe diameter after the reducing deformation is the same as that before flaring in the step one;

step three, still maintaining the clamping of the pipe body 2 of the exhaust gas recirculation water inlet and outlet pipe, and performing axial extrusion on the reserved wave band 5 by adopting an axial extrusion punch as shown in fig. 6 until the axial length of the finished annular convex diameter 1 is reached to complete the processing of the convex diameter of the pipe orifice;

and step four, continuously keeping clamping the pipe body 2 of the waste gas recirculation water inlet and outlet pipe, and necking the pipe orifice end surface 6 by adopting a pipe orifice end surface necking punch as shown in figure 7 to obtain a finished product.