CN110253721A - A kind of processing method of asymmetric structure honeycomb ceramics, mold and mold - Google Patents

Abstract

The invention discloses a honeycomb ceramic with an asymmetric structure, which belongs to the technical field of honeycomb ceramics. The honeycomb ceramic is alternately provided with inlet passages and outlet passages. The cross-sections of the inlet passages and the outlet passages are square. The area is larger than the cross-sectional area of the outlet channel. The advantage is that the inlet channel has a large soot capacity. When it is made into a wall-flow honeycomb ceramic filter body, it can effectively reduce the pressure drop in the later stage and prolong the service life. The invention also discloses a manufacturing method of the asymmetric structure honeycomb ceramic and the mould.

Description

A kind of processing method of asymmetric structure honeycomb ceramics, mold and mold

technical field

The invention relates to the technical field of honeycomb ceramics, in particular to a honeycomb ceramic with an asymmetric structure, a mold and a processing method for the mold.

Background technique

Honeycomb ceramic wall-flow filter can remove carbon black in gasoline engine and diesel engine exhaust. The current traditional filter design has an inlet and outlet honeycomb ceramic surface as the inlet and outlet, and a porous wall separating the inlet and outlet. These interconnected walls divide the filter into an inlet channel (abbreviation: I) and an outlet channel (abbreviation: O). To capture carbon black and ash, the outlet end of the inlet channel is blocked and the inlet of the outlet channel is blocked. Such an alternately blocked structure is like a chess board. This design forces the exhaust gas to pass through the porous walls, allowing particulate matter to settle in the channels or on the walls. Usually, the inlet and outlet channels have a square cross-section of the same area. When the amount of carbon black reaches a certain level, the regeneration process takes place, which will burn off the carbon black.

In use, it has also been found that ash is also deposited in the inlet channel. These ash particles, consisting of metal oxides, sulphates, phosphates and other substances, are non-combustible and so are not burned during the regeneration process. Therefore, the ash will remain deposited in the inlet channel until it is mechanically cleaned out. Therefore, before the ash is washed out, as the running time of the engine increases, the ash in the honeycomb ceramic inlet channel will increase, and the back pressure of the entire exhaust gas treatment system will obviously increase.

Currently, one way to reduce the effect of ash on back pressure is to increase the area of the inlet channel. For the same cross-sectional area, this means reducing the area of the outlet channel. In this way, more particulate matter (carbon black and ash) can be accommodated in the enlarged inlet passage, that is, the filter's ability to store particulate matter is increased, thereby reducing back pressure. In some designs where space is limited, this structure is very important to help small filters. Under the condition that the mesh number of the filter remains unchanged, the increase of the inlet channel will result in a smaller distance between the corners of two adjacent inlet channels. When the distance becomes smaller, the mechanical strength of the filter will be weakened, which will cause a series of problems in production and application.

Contents of the invention

The invention provides a honeycomb ceramic with an asymmetric structure, which has the advantages of large soot capacity in the inlet channel, and can effectively reduce the pressure drop in the later stage and prolong the service life when it is made into a wall-flow type honeycomb ceramic filter body.

The above object of the present invention is achieved by the following technical solutions, a kind of asymmetric structure honeycomb ceramics, the honeycomb ceramics are alternately provided with inlet passages and outlet passages, the cross-sections of the inlet passages and outlet passages are square, the inlet passages The cross-sectional area of the channel is greater than the cross-sectional area of the outlet channel.

According to the present invention, the cross-sectional area ratio of the inlet channel to the outlet channel is in the range of 1.2-2.25.

The present invention further provides that the four corners of the inlet channel are provided with rounded corners or beveled corners.

On the other hand, the present invention provides an asymmetric structure honeycomb ceramic mold for processing the above asymmetric structure honeycomb ceramics, comprising a platform, one side of the platform is provided with several feeding holes evenly distributed, the other side of the platform There are several large square columns and small square columns alternately arranged on the side, the shape of the large square columns is complementary to the inlet channel, the shape of the small square columns is complementary to the outlet channel, and the feed hole is connected to the gap between the large square columns and the small square columns For the discharge chute.

The present invention is further provided that the cross section of the feed hole is circular and the center of the feed hole coincides with the diagonal center of two adjacent large square columns and small square columns.

In yet another aspect, the present invention provides a method for processing an asymmetric structure honeycomb ceramic mold, which is used to process the above-mentioned asymmetric structure honeycomb ceramic mold, comprising the following steps:

S1: Select the mold steel blank to process the circular mold blank by machining;

S2: process the feeding hole on one side of the circular mold blank by means of numerical control machining;

S3: Polishing the feed hole to obtain a deep hole mold body;

S4: Process the tooth platform from the circular mold blank by turning to obtain the deep hole mold blank with the tooth platform;

S5: cleaning, drying and then heat-treating the deep-hole mold body with gear table obtained in step S4;

S6: Grinding the front and back sides of the deep-hole mold with gear table obtained in step S5;

S7: EDM the discharge trough to communicate with the feed hole;

S8: Cleaning and debugging the processed mold.

It is further provided in the present invention that the step S7 further includes setting an electrode, the electrode is used for machining the discharge groove by electric discharge, and the shape of the electrode matches the discharge groove.

The present invention is further provided that the step S2 further includes machining positioning holes on the outer edge of the circular mold blank, and the outer edge of the electrode is provided with corresponding electrode positioning holes.

In summary, the beneficial effects of the present invention have:

1. When the honeycomb ceramics in the present invention are made into a wall-flow honeycomb ceramic filter body, since the inlet channel is larger than the outlet channel, the soot capacity of the inlet channel is improved, the back pressure in the later stage is reduced and the life is prolonged. Angle, alleviating the strength drop caused by increasing the cross-sectional area of the inlet channel;

2. The asymmetric structure honeycomb ceramic mold in the present invention is used for processing asymmetric structure honeycomb ceramics, the mold can be used to process asymmetric structure honeycomb ceramics on an extruder, the process is simple, the production efficiency is high, and the feeding of the asymmetric structure honeycomb ceramic mold The hole is used for mud entry, and the discharge chute is used for mud discharge, and the mud blank can be formed after being extruded from the discharge chute;

3. In the processing method of the asymmetric structure honeycomb ceramic mold in the present invention, the discharge groove is processed by electric discharge, and the processing precision is high.

Description of drawings

Fig. 1 is a schematic structural view of an asymmetric honeycomb ceramic in Example 1 of the present invention;

Fig. 2 is the top view of the asymmetric structure honeycomb ceramic mold in the second embodiment of the present invention;

Fig. 3 is a side sectional view of an asymmetric structure honeycomb ceramic mold in Example 2 of the present invention;

Fig. 4 is the schematic diagram of circular mold blank in the embodiment of the present invention three;

Fig. 5 is the top view of the deep hole mold blank in the third embodiment of the present invention;

Fig. 6 is a side sectional view of the deep hole mold blank in Example 3 of the present invention;

Fig. 7 is a side sectional view of a deep-hole mold body with gear stages in Example 3 of the present invention;

Fig. 8 is a top view of an electrode in Embodiment 3 of the present invention;

Fig. 9 is a side sectional view of an electrode in Embodiment 3 of the present invention;

Fig. 10 is a schematic diagram of a grid surface of an electrode in Embodiment 3 of the present invention;

Fig. 11 is a diagram showing the relationship between the grid surface of the electrode and the deep hole of the deep hole mold blank with gear stages during EDM in the third embodiment of the present invention.

In the figure, 1. Inlet channel; 2. Outlet channel; 3. Platform; 4. Feed hole; 5. Large square column; 6. Small square column; 7. Outlet chute; 8. Positioning hole; 9. Electrode positioning hole .

Detailed ways

Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

Embodiment 1: A honeycomb ceramic with an asymmetric structure, referring to Fig. 1, the inlet channel 1 and the outlet channel 2 are arranged alternately on the honeycomb ceramic, the cross sections of the inlet channel 1 and the outlet channel 2 are square, and the inlet channel 1 The cross-sectional area is larger than the cross-sectional area of the outlet channel 2, and the ratio of the cross-sectional area of the inlet channel 1 to the outlet channel 2 ranges from 1.2 to 2.25. Preferably, the ratio of the cross-sectional area of the inlet channel 1 to the outlet channel 2 is 1.5. The corners of the outlet channel 2 are right angles. In order to improve the strength of the honeycomb ceramics, the four corners of the inlet channel 1 are provided with rounded corners. It can be understood that the rounded corners can also be set as beveled corners.

In the asymmetric wall-flow honeycomb ceramic filter body, the inlet channel 1 and the outlet channel 2 of the honeycomb ceramics are blocked alternately, the exhaust gas enters the honeycomb ceramics from the inlet channel 1, enters the outlet channel 2 through the gap of the honeycomb ceramics, and is discharged. The cross-sectional area of the inlet channel 1 increases the soot capacity of the inlet channel 1, reduces the back pressure in the later stage and prolongs the life.

Embodiment 2: A kind of asymmetric structure honeycomb ceramics, for processing asymmetric structure honeycomb ceramics, refer to Fig. 2-Fig. One side of the feeding hole 4 is the mud feeding surface, and the feeding hole 4 is used for mud feeding, and the other side of the platform 3 is alternately provided with several large square columns 5 and small square columns 6, and the large square columns 5 and the inlet channel 1. Complementary in shape, the shape of the small square column 6 is complementary to that of the outlet channel 2, the gap between the feed hole 4 connected to the large square column 5 and the small square column 6 is the discharge chute 7, and the discharge chute 7 of the platform 3 is a The side is the mud outlet surface of platform 3. In Fig. 2, the large square grid is a large square column, the small square grid is a small square column, and the black grid between the large square column 5 and the small square column 6 is a discharge trough; in Fig. 3, the large square column 5 and the small square column The white gap between the columns 6 is the discharge groove 7, and the color of the discharge groove 7 in Fig. 2 and Fig. 3 is different, which is explained here.

Further, the cross-section of the feed hole 4 is circular and the center of the feed hole 4 coincides with the diagonal centers of the two adjacent large square columns 5 and small square columns 6 (refer to FIG. 11 here. ).

The mud blank for manufacturing honeycomb ceramics enters from the feed hole 4 and is extruded from the discharge groove 7 to form, and after consolidation and firing, the processing of the asymmetric honeycomb ceramics is completed.

Embodiment 3: A processing method of an asymmetric structure honeycomb ceramic mold, for processing the above-mentioned asymmetric structure honeycomb ceramic mold, comprising the following steps:

S1: Choose mold steel blanks to process circular mold blanks by machining; specifically, use high-quality mold steel blanks to make diameter (D) and height (H) on lathes and grinders according to the size of the mold to be processed The circular mold blank, the circular mold blank refers to Figure 4. It can be understood that the circular mold blank can also be processed by other equipment, not limited to lathes and grinders.

S2: Process the feeding hole on one side of the circular mold blank by CNC machining; specifically, according to the mesh number, diameter (specification model) and raw material shrinkage ratio of the mold to be processed on the horizontal CNC deep hole drilling machine Carry out programming, set the drilling range, the hole spacing of the uniformly distributed mold feed holes, the drilling depth, the time and other programs. Fix the circular mold blank on the horizontal CNC deep hole drilling reference plane for drilling operations. Firstly, perform center drilling positioning operations according to the set program, and set the positioning holes to ensure the accuracy of the next drilling operation. precision. Then select a hollow long-handled alloy steel drill bit with a suitable diameter according to the mesh number of the product and the amount of mud entering for drilling operations. When the hollow long-handled alloy steel drill bit is drilling, the center is cooled and the lubricating oil flows out, which reduces the temperature generated by drilling. At the same time, the outflowing oil can take away the slag and iron filings produced by drilling, ensuring the accuracy and efficiency of drilling.

S3: Polish the feed hole to obtain the deep hole mold body; after the drilling is completed, replace the polishing drill with a 45-degree angle at the front end, and polish the deep hole in turn to ensure the smoothness of the deep hole, so as to ensure the mud entry Uniformity and consistency, the deep hole mold blank is obtained, and the deep hole mold blank is shown in Figure 5-6.

S4: Process the tooth platform on the circular mold blank by turning to obtain the deep hole mold blank with tooth platform; the mud outlet surface of the circular mold blank is determined according to the drilling range (d) and the mold tooth height (h ) on the CNC lathe to turn the mold tooth table, the height of the tooth table is generally 4.5mm, and the height of the mold tooth table should exceed the bottom hole of the feed by about 0.6mm, and the deep hole mold body with the tooth table is obtained (as shown in Figure 7)

S5: cleaning, drying and then heat-treating the deep-hole mold body with gear table obtained in step S4;

S6: Grinding the front and back sides of the deep hole mold blank with toothed platform obtained in step S5; grinding the front and back sides of the deep hole mold blank with gear platform after heat treatment through a high-precision surface grinder Machining to eliminate micro-deformation caused by heat treatment.

S7: The discharge groove is processed by EDM until it communicates with the feed hole; the asymmetric wall flow is determined according to the hole spacing of the deep-hole mold body with gear table, the wall thickness of the produced product, and the volume ratio of the inlet and outlet holes Then select the electrode material with good conductivity to make an electrode module with the diameter of the circular mold blank, and produce electrodes with small and large holes spaced apart by programming on the electrode processing machine tool. (as shown in Figure 8-9), the large hole is a square hole with a rounded corner R0.15, the small hole is a square hole (as shown in Figure 10), the electrode wall height is about 6mm, and the electrode wall thickness is smaller than the product wall thickness 0.08mm leaves a discharge gap during processing. High-precision EDM machine tools are used, and the asymmetrical discharge groove 7 (square holes arranged in alternate sizes) is processed by EDM using the processed electrode module. During processing, the grid surface of the electrode module and the depth of the tooth table The tooth table surface of the hole mold blank is opposite. In order to ensure the position of the tooth table surface of the deep hole mold blank and the electrode, the positioning hole 8 is processed on the outer edge of the deep hole mold blank (refer to Figure 5 and Figure 6), and the outer edge of the electrode is set. There are corresponding electrode positioning holes 9 (refer to Fig. 8 and Fig. 9). During processing, use pins to insert into the positioning holes 8 and electrode positioning holes 9 to realize the positioning of the tooth table surface and the electrode of the deep hole mold blank. The four positioning holes of the pole module correspond to the four positioning holes of the deep-hole mold blank with tooth table, ensuring that the center of each feed hole corresponds to the diagonal center of two adjacent four holes at the mud outlet of the mold. As shown in Figure 11, the circular dotted line in the figure represents the feeding hole on the deep hole mold blank. Usually, due to electrode loss during processing, 1 set of molds requires 3~4 sets of electrodes. During EDM, it is necessary to ensure that the processing depth reaches 4.5mm, so that the feed hole of the mold can communicate with the grid to form an asymmetric honeycomb ceramic mold.

S8: Cleaning and debugging the processed mold. Finally, the added asymmetric honeycomb ceramic mold is cleaned (usually soaked in gasoline for 24 hours to remove oil stains, and then rinsed with a high-pressure water gun), the mold sleeve is prepared, and the mold is debugged on the molding press until the mold Until the mud is uniform and smooth, and the grid has no broken wire defects, the mold can be used for production operations.

The above is only the preferred embodiment of the present invention, it should be pointed out that for those skilled in the art, without departing from the inventive concept of the present invention, some modifications and improvements can also be made, and these all belong to the present invention. protection scope of the invention.

Claims (8)

1. a kind of asymmetric structure honeycomb ceramic, it is characterized in that, described honeycomb ceramic is alternately provided with inlet channel (1) and outlet channel (2), and the cross section of described inlet channel (1) and outlet channel (2) is Square, the cross-sectional area of the inlet passage (1) is larger than the cross-sectional area of the outlet passage (2). 2. The ceramic honeycomb with an asymmetric structure according to claim 1, characterized in that the ratio of the cross-sectional area of the inlet channel (1) to the outlet channel (2) is in the range of 1.2-2.25. 3. The ceramic honeycomb with asymmetric structure according to claim 1, characterized in that, the four corners of the inlet channel (1) are provided with rounded corners or beveled corners. 4. A kind of asymmetric structure honeycomb ceramic mold, is used for processing the described asymmetric structure honeycomb ceramic of claim 3, is characterized in that, comprises platform (3), and one side of platform (3) is provided with some evenly distributed Material holes (4), the other side of the platform (3) are alternately provided with several large square columns (5) and small square columns (6), the shape of the large square columns (5) and the inlet channel (1) are complementary, so The shape of the small square pillar (6) is complementary to that of the outlet channel (2), and the gap between the feed hole (4) connected to the large square pillar (5) and the small square pillar (6) is a discharge groove (7). 5. asymmetric structure honeycomb ceramic mold according to claim 4, is characterized in that, the cross-section of described feed hole (4) is circular and the center of described feed hole (4) and two adjacent The diagonal centers of the large square column (5) and the small square column (6) coincide. 6. A processing method for an asymmetric structure honeycomb ceramic mold, for processing the asymmetric structure honeycomb ceramic mold according to claim 5, characterized in that, comprising the following steps: S1: Select the mold steel blank to process the circular mold blank by machining; S2: process feed hole (4) on one side of circular mold blank by the mode of numerical control machining; S3: Polishing the feed hole (4) to obtain a deep hole mold body; S4: Process the tooth platform from the circular mold blank by turning to obtain the deep hole mold blank with the tooth platform; S5: cleaning, drying and then heat-treating the deep-hole mold body with gear table obtained in step S4; S6: Grinding the front and back sides of the deep-hole mold with gear table obtained in step S5; S7: EDM the discharge trough (7) to communicate with the feed hole (4); S8: Cleaning and debugging the processed mold. 7. The processing method of the asymmetric structure honeycomb ceramic mold according to claim 6, characterized in that, the step S7 also includes setting an electrode, and the electrode is used to process the discharge groove (7) by electric discharge machining, The shape of the electrodes matches the discharge groove (7). 8. The processing method of the asymmetric structure honeycomb ceramic mold according to claim 6, characterized in that, said step S2 also includes machining positioning holes (8) on the outer edge of the circular mold blank, the outer edge of the electrode The edge is provided with corresponding electrode positioning holes (9).