EGR (Exhaust Gas Recirculation) valve rod with integral structure

Abstract

The invention provides an EGR valve rod of an integral structure. The valve rod comprises a valve rod body and a disc part which are integrally connected. The end, away from the disc part, of the valve rod is provided with a chamfer, and the end, close to the disc part, of the valve rod is in arc surface transition with the disc part. The valve rod manufacturing process comprises the steps of blanking, forming, tempering, rough shot blasting, correction, total length cutting, rod rough grinding, small end chamfering, rod end fine grinding, disc part turning, end face turning, disc part R fine turning, fine shot blasting, rod semi-fine grinding, rod fine grinding, full inspection, packaging and warehousing and the like. According to the process, a traditional valve rod machining mode is abandoned, the disc part and the valve rod are connected more stably, the machining process is reduced, cost is reduced, and the structure is simpler and more reliable.

Description

Technical Field

[0001] The invention relates to the technical field of engine tail gas emission control devices, and in particular to an EGR valve stem with an integral structure. Background Art

[0002] The engine exhaust gas recirculation system (EGR system for short) is used to reduce the emission of nitrogen oxides in the exhaust gas. When the EGR valve is opened, part of the exhaust gas discharged by the engine can be returned to the intake manifold and enter the cylinder together with the fresh combustible mixture for re-combustion to achieve optimal combustion and reduce the emission of pollutants to meet the emission requirements. The EGR valve stem plays the role of regulating the exhaust gas flow control in the electric EGR valve. Whether the EGR valve stem can work stably and reliably directly affects the operating performance of the engine.

[0003] The lower end of the EGR valve stem is provided with a disc. Existing EGR valve stems generally adopt a split manufacturing method, that is, the valve stem and the disc are manufactured separately and then connected together by welding or riveting. During normal operation, the disc will constantly hit the valve port. The split manufacturing method has defects in cumulative error control, quality stability and operating action. After long-term use, the valve stem and the disc will fall off due to insufficient connection strength.

[0004] Therefore, developing an integral EGR valve stem is of great significance to product performance stability and service life. Summary of the invention

[0005] The purpose of the present invention is to provide an EGR valve stem with an integral structure and a manufacturing process to solve the problems existing in the prior art.

[0006] The technical solution adopted to achieve the purpose of the present invention is as follows: an integral structure EGR valve stem, comprising a valve stem and a disc portion connected in one piece. The end of the valve stem away from the disc portion is chamfered, and the end close to the disc portion is transitioned with the disc portion by an arc surface.

[0007] Furthermore, the disk portion is in a flat top shape or a spherical top shape.

[0008] Furthermore, an annular oil storage groove is provided in the circumferential direction of the upper edge of the stem of the valve stem.

[0009] Furthermore, the side walls of the annular oil storage groove expand outwards from the bottom of the groove to the top of the groove.

[0010] The present invention also discloses a manufacturing process of the EGR valve stem, which comprises the following steps:

[0011] 1) Cutting: Cut the raw material bar into single bars according to the required length.

[0012] 2) Forming. The single bar is processed to form the basic shape of the EGR valve stem. One end of the single bar is heated on the electric upsetting machine, and the other end is pressurized by the oil cylinder, and the heated end is hot extruded into a garlic shape. The workpiece that has been upset by the electric upsetting is placed in the mold of the press station and is stamped into an integrated part blank by the press.

[0013] 3) Tempering. The one-piece part blank is placed in a mesh belt furnace for automatic tempering.

[0014] 4) Rough shot blasting.

[0015] 5) Perform preliminary machining on the one-piece part blank.

[0016] 5.1) Correction: Correct the deformation of the valve stem and disc to the process requirements.

[0017] 5.2) Cut the total length. Cut off the part of the valve stem that exceeds the length specified by the process.

[0018] 6) Perform fine machining to ensure the final size and shape accuracy of the EGR valve stem.

[0019] 6.1) Small end chamfer: Chamfer the valve stem end.

[0020] 6.2) Fine grinding of the stem end: Fine grinding of the stem end is performed to achieve the required length and roughness standards.

[0021] 6.3) Rough grinding of the stem. Rough grinding of the valve stem.

[0022] 6.4) Turning the disc part. The outer circle of the disc part and the sealing surface are machined to obtain the specifications and standards required by the process.

[0023] 6.5) Finish turning the disc part R. Process the transition part between the valve stem and the disc part.

[0024] 6.6) Semi-finished rod.

[0025] 6.7) Fine grinding of the rod.

[0026] 7) Precision shot blasting.

[0027] 8) Conduct a complete inspection of the EGR valve stem appearance and assembly dimensions.

[0028] Furthermore, in step 1), an automatic cutting machine is used to automatically feed the rod into the cutting mold.

[0029] Furthermore, in step 4), the tumble shot blasting machine is used to blast the stainless steel shot with a size of 0.3 mm to 0.5 mm for a certain period of time.

[0030] Furthermore, steps 5.2), 6.1) and 6.2) are processed using a CBN grinder.

[0031] Furthermore, steps 6.3), 6.6) and 6.7) are processed using a CNC automatic centerless grinder.

[0032] Furthermore, after step 8), there is also a step of packaging and warehousing.

[0033] The technical effect of the present invention is unquestionable: it eliminates the traditional valve stem processing method, the connection between the disc and the valve stem is more stable, the processing process is reduced, the cost is reduced, and the structure is simpler and more reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of the EGR valve stem structure;

[0035] Figure 2 Schematic diagram of the EGR valve stem manufacturing process.

[0036] In the figure: valve stem 1, disc 2. DETAILED DESCRIPTION

[0037] The present invention is further described below in conjunction with the embodiments, but it should not be understood that the above subject matter of the present invention is limited to the following embodiments. Without departing from the above technical ideas of the present invention, various substitutions and changes are made according to the common technical knowledge and customary means in the art, which should all be included in the protection scope of the present invention.

[0038] Embodiment 1:

[0039] See also Figure 1 This embodiment provides an integral structure EGR valve stem, including a valve stem 1 and a disc 2 connected in one piece. The end of the valve stem 1 away from the disc 2 is provided with a chamfer, and the end close to the disc 2 is transitioned with the disc 2 by an arc surface. In this embodiment, the disc 2 is flat-topped. In actual production, the disc 2 can also be spherical.

[0040] Embodiment 2:

[0041] The main contents of this embodiment are the same as those of embodiment 1, wherein an annular oil storage groove may or may not be provided on the circumference of the upper edge of the stem of the valve stem 1. The side walls of the annular oil storage groove expand outward from the bottom of the groove to the top of the groove.

[0042] Embodiment 3:

[0043] This embodiment provides a manufacturing process for the EGR valve stem described in Embodiment 1 or 2. The morphological features of the workpiece after each step in the manufacturing process are as follows: Figure 2 As shown. The EGR valve stem manufacturing process includes the following steps:

[0044] 1) Cutting. Cut the raw material bar into single bars according to the required length. The shape of a single bar is as follows: Figure 2 As shown in A.

[0045] 2) Forming. A single bar is processed to form the basic shape of the EGR valve stem. One end of the single bar is heated on the electric upsetting machine, and pressure is applied to the other end by the oil cylinder. The heated end is gradually upset and deformed into a garlic shape under high temperature and high pressure. The electric upsetting process is stopped after the pre-set parameter effect is reached. The robot puts the upset workpiece into the mold of the press station, and the press is used to stamp it into an integrated part blank.

[0046] 3) Tempering. After the mesh belt furnace is set to the temperature and time required for the process, the one-piece part blank is loaded into the mesh belt furnace for automatic tempering. After tempering, the morphology of the one-piece part blank is as follows: Figure 2 As shown in B. After processing in step 2) and step 3), the size, appearance and metallographic structure characteristics of the workpiece change.

[0047] 4) Rough shot blasting.

[0048] 5) Perform preliminary machining on the one-piece part blank.

[0049] 5.1) Calibration: The deformation of the valve stem 1 and the disc 2 is calibrated to the process requirement standard.

[0050] 5.2) Cut the total length. Cut off the part of the valve stem 1 that exceeds the length specified by the process. After cutting the total length, the appearance of the workpiece is as follows: Figure 2 C. After processing in step 5), the size of the workpiece changes.

[0051] 6) Perform fine machining to ensure the final size and shape accuracy of the EGR valve stem.

[0052] 6.1) Small end chamfering: Chamfer the end of valve stem 1.

[0053] 6.2) Fine grinding of the rod end. Fine grinding of the rod end of valve stem 1 to meet the process requirements of length and roughness standards. After fine grinding of the rod end, the morphology of the workpiece is as follows: Figure 2 As shown in D.

[0054] 6.3) Rough grinding of the stem. Rough grinding of the stem 1. After rough grinding of the stem, the morphology of the workpiece is as follows: Figure 2 As shown in E.

[0055] 6.4) Turning the disc part 2. The outer circle and sealing surface of the disc part 2 are machined to obtain the specifications required by the process.

[0056] 6.5) Finish turning the disc part 2R. Process the transition part between the stem 1 and the disc part 2. After finishing the disc part 2R, the appearance of the workpiece is as follows Figure 2 As shown in E.

[0057] 6.6) Semi-finished rod.

[0058] 6.7) Fine grinding of the rod. After the treatment in step 5), the size of the workpiece changes. After fine grinding of the rod, the morphology of the workpiece is as follows Figure 2 As shown in E. After processing in step 6), the size of the workpiece changes.

[0059] 7) Precision shot blasting.

[0060] 8) Conduct a full inspection of the EGR valve stem appearance and assembly dimensions. Use visual inspection and testing equipment to conduct 100% inspection of the appearance of parts and key assembly dimensions to ensure that 100% of the assembly requirements are met.

[0061] Embodiment 4:

[0062] The main contents of this embodiment are the same as those of Embodiment 3, wherein, in step 1), an automatic cutting machine is used to automatically feed a 4 m long bar into a cutting mold. The cutting machine is pre-set with predetermined length dimension parameters. After one end of the bar contacts the set position sensor, the cutting machine will automatically cut the material to obtain the required length of a customized single bar.

[0063] Embodiment 5:

[0064] The main contents of this embodiment are the same as those of Embodiment 3 or 4, wherein the stainless steel shots with a specification of 0.3 mm to 0.5 mm are used for shot blasting in a rolling shot blasting machine for a certain period of time.

[0065] Embodiment 6:

[0066] The main contents of this embodiment are the same as any one of embodiments 3 to 5, wherein steps 5.2), 6.1) and 6.2) are processed using a CBN grinder.

[0067] Embodiment 7:

[0068] The main contents of this embodiment are the same as any one of Embodiments 3 to 6, wherein steps 6.3), 6.6) and 6.7) are processed using a CNC automatic centerless grinder.

[0069] Embodiment 8:

[0070] The main contents of this embodiment are the same as any one of Embodiments 3 to 7, wherein step 8) is followed by the steps of packaging on a packaging machine and packaging into storage.

Claims

1. An integral structure EGR valve stem, characterized in that: It comprises an integrally connected valve stem (1) and a disc portion (2); the end of the valve stem (1) away from the disc portion (2) is provided with a chamfer, and the end close to the disc portion (2) is transitioned to the disc portion (2) by an arc surface.

2. The EGR valve stem of the integral structure according to claim 1, characterized in that: The disk portion (2) is in the shape of a flat top or a spherical top.

3. The EGR valve stem of the integral structure according to claim 1, characterized in that: An annular oil storage groove is provided in the circumferential direction of the upper edge of the stem of the valve stem (1).

4. The EGR valve stem of the integral structure according to claim 3 is characterized in that: The side walls of the annular oil storage groove expand outwards from the groove bottom to the groove top.

5. A manufacturing process of an integral structure EGR valve stem according to any one of claims 1 to 4, characterized in that: The following steps are involved: 1) Cutting: Cut the raw material bars into single bars according to the required length; 2) Forming: processing a single bar stock to form the basic shape of the EGR valve stem; One end of a single bar is heated on the electric upsetting machine, and the other end is pressurized by the oil cylinder, and the heated end is hot extruded into a garlic shape; the workpiece that has been upset by the electric upsetting is placed in the mold of the press station, and is stamped into an integrated part blank by the press; 3) Tempering: Place the one-piece part blank into the mesh belt furnace for automatic tempering; 4) Rough shot blasting; 5) Perform preliminary machining on the one-piece part blank; 5.1) Calibration: Calibrate the deformation of the valve stem (1) and the disc (2) to the process requirement standard; 5.2) Cut the total length; cut off the part of the valve stem (1) that exceeds the length specified by the process; 6) Perform fine machining to ensure the final size and shape accuracy of the EGR valve stem; 6.1) Small end chamfering: Chamfer the end of the valve stem (1); 6.2) Fine grinding of the stem end: Fine grinding of the stem end (1) to meet the process requirements of length and roughness; 6.3) Rough grinding of the stem: Rough grinding of the stem (1); 6.4) Turning the disc part (2); cutting the outer circle and the sealing surface of the disc part (2) to obtain the specifications and standards required by the process; 6.5) Fine turning the disc part (2) R; processing the transition part between the stem (1) and the disc part (2); 6.6) Semi-finished rod; 6.7) Fine grinding of rods; 7) Precision shot blasting; 8) Conduct a complete inspection of the EGR valve stem appearance and assembly dimensions.

6. The manufacturing process of the EGR valve stem with an integral structure according to claim 5 is characterized in that: In step 1), an automatic cutting machine is used to automatically feed the bar into the cutting mold.

7. The EGR valve stem manufacturing process according to claim 5, characterized in that: In step 4), the 0.3 mm to 0.5 mm stainless steel shot is used for shot blasting for a certain period of time in a rolling shot blasting machine.

8. The manufacturing process of the EGR valve stem with an integral structure according to claim 5, characterized in that: Step 5.2), step 6.1) and step 6.2) are processed using a CBN grinder.

9. The manufacturing process of the EGR valve stem with an integral structure according to claim 5, characterized in that: Step 6.3), step 6.6) and step 6.7) are processed using a CNC automatic centerless grinder.

10. The manufacturing process of the EGR valve stem with an integral structure according to claim 5, characterized in that: After step 8), there is also a step of packaging and warehousing.

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