Ceramic shell forming mold structure

Abstract

The ceramic shell forming die structure comprises an upper stamping die, a middle die, a lower stamping die and a floating stamping die, a die hole is formed in the middle die, powder overflowing grooves are formed in the positions, corresponding to the two sides of the die hole, of the middle die respectively, the powder overflowing grooves are formed in the middle of the upper end of the middle die, the upper ends of the powder overflowing grooves are open, and the lower ends of the powder overflowing grooves are open. The length of the powder overflow groove is 5%-15% of the length of the ceramic shell, the width of the powder overflow groove is 2-3 mm, the depth of the powder overflow groove is 5%-10% of the height of the ceramic shell, the upper punching die is located above the die hole, the lower punching die is located below the die hole, a cavity for the floating punching die to stretch into is formed in the lower punching die, and the floating punching die is located in the cavity. The upper end of the floating punching die protrudes out of the upper end of the lower punching die. According to the ceramic shell forming mold structure, the problem of deformation caused by size shrinkage in the sintering process of a ceramic shell and the problem of cracking of the ceramic shell caused by density difference are solved.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic molding, and in particular to a ceramic shell molding die structure. Background Art

[0002] The structure of the ceramic shell is as follows Figure 1 As shown, it is often used for on-off control and circuit protection of power circuits, and is widely used in power, new energy vehicles, energy storage and other fields. In recent years, the development of industries such as power, new energy vehicles, and energy storage has maintained a steady growth trend. In addition, with the transformation of rural networks, the expansion and upgrading of urban power grids, and the continuous deepening of new energy development and utilization, the use of ceramic shells has increased year by year. As one of the core parts of power appliances and new energy, ceramic shells have considerable advantages in insulation, strength, airtightness, etc., and have been widely recognized and used by the industry.

[0003] The structure of the existing ceramic shell forming mold includes an upper punch, a lower punch, a middle die and a floating die. The middle die is provided with a die hole, and the shape of the die hole is the shape of the ceramic shell. The lower punch is provided with a cavity, and the floating die can move up and down in the cavity. The lower punch is located below the die hole, and the upper punch is located above the die hole. A slot is provided at the bottom of the upper punch. During forming, the die hole is filled with powder, and the powder is dry-pressed and formed with the cooperation of the upper punch, the floating die, the middle die and the lower punch to obtain a ceramic shell blank. During the powder dry-pressing forming process of the ceramic shell blank, due to the density difference between the blank in the middle part and the blank at both ends (the powder density in the middle part is larger), the size shrinkage of the ceramic shell blank after sintering is inconsistent (the size shrinkage is smaller at the position with large powder density), and the middle part of the rectangular long side of the ceramic shell is easily deformed and convex, so that the final shape of the ceramic shell is slightly narrow at both ends and slightly wide in the middle, such as Figure 1 As shown; at the same time, the density difference between the middle and the two ends of the blank is prone to cracking in actual use.

[0004] The above deformation and cracking problems will eventually cause low reliability of the ceramic shell, affect assembly, reduce ceramic strength, etc. Therefore, the above structural problems are currently one of the troubles to ensure the production assembly and product quality of the ceramic shell dry pressing structure. Ceramic shell products produced using conventional mold structures can no longer meet the requirements of clients. Summary of the invention

[0005] The object of the present invention is to provide a ceramic shell forming die structure, which solves the problem of deformation of the ceramic shell due to size shrinkage during sintering and the problem of cracking of the ceramic shell due to density difference.

[0006] In order to achieve the above object, the solution of the present invention is: A ceramic shell forming die structure comprises an upper punch, a middle die, a lower punch and a floating die, wherein a die hole is arranged in the middle die, and powder overflow grooves are respectively opened at positions on both sides of the middle die corresponding to the die hole, each of the powder overflow grooves is arranged in the middle of the upper end of the middle die, and the upper end of each of the powder overflow grooves is open, the length of each of the powder overflow grooves is 5% to 15% of the length of the ceramic shell, the width of each of the powder overflow grooves is 2 to 3 mm, and the depth of each of the powder overflow grooves is 5% to 10% of the height of the ceramic shell, the upper punch is located above the die hole, the lower punch is located below the die hole, a cavity for the floating punch to extend into is arranged in the lower punch, and the upper end of the floating punch extends into the die hole from the upper end of the lower punch.

[0007] The powder overflow grooves are arranged symmetrically with respect to the center.

[0008] The root of the groove bottom of each of the powder overflow grooves is an arc surface with an R angle transition, and the radius of the arc surface is equal to the width of the powder overflow groove.

[0009] A plurality of through-channels are arranged in the floating punch die, and a hole-forming core rod is inserted into each of the through-channels.

[0010] One end of each of the hole-forming mandrels extends into or out of the die hole, and the other end of each of the hole-forming mandrels is mounted on a mounting seat, and the mounting seat is connected to a mandrel driving assembly.

[0011] The core rod driving assembly is a first driving cylinder, and the piston rod of the first driving cylinder is connected to the mounting seat to drive each of the hole-forming core rods to move up and down.

[0012] The bottom of the upper punch die is provided with an upper punch which extends into the die hole and extrude powder into a mold. The extrusion surface of the upper punch die is provided with a plurality of slot holes which correspond to the through-channels and accommodate the corresponding ends of each of the hole-forming core rods.

[0013] The middle mold is connected with a middle mold driving component.

[0014] The middle mold driving assembly is a second driving cylinder, and a piston rod of the second driving cylinder is connected to the middle mold to drive the middle mold to move up and down.

[0015] After adopting the above structure, the present invention provides a ceramic shell forming mold structure, in which powder overflow grooves are respectively opened on both sides of the mold hole corresponding to the middle part of the upper end of the middle mold, and the powder overflow grooves are communicated with the mold hole. During the powder dry pressing process, excess powder corresponding to the middle part of the ceramic shell blank will be squeezed out of the middle mold through the powder overflow grooves, thereby eliminating the density difference between the middle part and the two ends of the ceramic shell blank, so that the ceramic shell blank can shrink in the same proportion during the sintering process without deformation and cracking, so that the final sintered ceramic shell has a square shape without deformation and better dimensional consistency. Moreover, since this density difference is eliminated, the ceramic shell is not easy to crack, the ceramic strength is higher, and the product qualification rate is improved.

[0016] Furthermore, in order to ensure that the "density difference" mentioned in this case can be eliminated without affecting the dry pressing of the ceramic shell, it is necessary to control the size of the powder overflow groove. If the size of the powder overflow groove is too large, too much powder will be squeezed out, and the ceramic shell will not be of sufficient size or even cannot be formed. If the size of the powder overflow groove is too small, the excess powder cannot be discharged out of the middle mold, and the purpose of eliminating the density difference cannot be achieved. Therefore, in the invention, the length of each powder overflow groove is controlled to be 5%~15% of the length of the ceramic shell, the width of each powder overflow groove is 2~3 mm, the depth of each powder overflow groove is 5%~10% of the height of the ceramic shell, and the root of the groove bottom of each powder overflow groove is an arc surface with R angle transition, and the radius of the arc surface is equal to the width of the powder overflow groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a ceramic shell in the prior art; Figure 2 A schematic structural diagram of a ceramic shell forming die structure of the present invention; Figure 3 It is a structural schematic diagram of the upper punch die in the present invention; Figure 4 It is a structural schematic diagram of the middle mold in the present invention; Figure 5 It is a schematic diagram of the dimensions of the middle mold in the present invention; Figure 6 Another schematic diagram of the size of the middle mold in the present invention; Figure 7 It is another schematic diagram of the size of the middle mold in the present invention; Figure 8 It is a structural schematic diagram of the lower punch die in the present invention; Fig. 9 It is a structural schematic diagram of the floating die in the present invention; Fig.10 It is a structural schematic diagram of the hole-forming mandrel in the present invention; Fig.11 It is a schematic diagram of the structure of a ceramic shell formed by dry pressing according to the present invention.

[0018] In the figure: Upper punch die 1; upper punch 11; Slot 12; Middle die 2; Die hole 21; powder overflow groove 22; Lower punch 3; cavity 31; Floating die 4; through channel 41; The core hole rod 5 is mounted on the seat 6. DETAILED DESCRIPTION

[0019] In order to further explain the technical solution of the present invention, the present invention is described in detail below through specific embodiments.

[0020] A ceramic shell forming mold structure, such as Figure 2-Figure 10 As shown, it includes an upper punch 1, a middle die 2, a lower punch 3 and a floating die 4. A die hole 21 is arranged in the middle die 2. The die hole 21 is a rectangular die hole, with the long side of the die hole 21 as the side and the short side of the die hole 21 as the end. Powder overflow grooves 22 are respectively opened on both sides of the middle die 2 corresponding to the die hole 21. Each powder overflow groove 22 is arranged in the middle of the upper end of the middle die 2, and the upper end of each powder overflow groove 22 is open. Preferably, each powder overflow groove 22 is centrally symmetrically arranged.

[0021] The length of the powder overflow groove 22 (denoted as l) is 5% to 15% of the length of the ceramic shell to be formed, the width of the powder overflow groove 22 (denoted as d) is 2 to 3 mm, the depth of the powder overflow groove 22 (denoted as h) is 5% to 10% of the height of the ceramic shell to be formed, and the root of the groove bottom of the powder overflow groove 22 is an arc surface with an R angle transition, and the radius of the arc surface is equal to the width d of the powder overflow groove 22.

[0022] The upper punch 1 is located above the die hole 21, and the lower punch 3 is located below the die hole 21. A cavity 31 is provided in the lower punch 3 for the floating die 4 to extend into. The shapes of the lower punch 3 and the floating die 4 are set according to the internal structure of the ceramic shell to be formed. For example, the mold structure disclosed in the utility model patent CN219114332U is a common lower punch structure. The upper end of the floating die 4 extends into the die hole 21 from the upper end of the lower punch 3. In the present invention, the assembly relationship among the upper punch 1, the middle die 2, the lower die 3, and the floating die 4 is common knowledge in the art. A molding space filled with powder is formed between the upper end of the floating die 4, the die hole 21 of the middle die 2, and the bottom of the upper punch 2.

[0023] A plurality of through-channels 41 are provided in the floating punch die 4, and a hole-forming mandrel 5 is inserted in each through-channel 41. One end of each hole-forming mandrel 5 extends into or out of the die hole 21, and the other end of each hole-forming mandrel 5 is mounted on a mounting seat 6, and a mandrel driving assembly is connected to the mounting seat 6. The mandrel driving assembly is a first driving cylinder, and a piston rod of the first driving cylinder is connected to the mounting seat 6 to drive each hole-forming mandrel 5 to move up and down.

[0024] The bottom of the upper punch die 1 is provided with an upper punch 11 extending into the die hole 21 and extruding the powder into a mold. The extrusion surface of the upper punch 11 is provided with a plurality of slots 12 corresponding to the through-channels 41 and accommodating the corresponding ends of each hole-forming core rod 5.

[0025] Furthermore, the middle mold 2 is connected to a middle mold driving assembly (not shown in the figure), and the middle mold driving assembly is a second driving cylinder. The piston rod of the second driving cylinder is connected to the middle mold to drive the middle mold to move up and down.

[0026] After adopting the above structure, a ceramic shell forming mold structure of the present invention is assembled and placed on a powder press. The hole-forming core rod 5 is first raised to the die hole 21 by the first driving cylinder to fill the powder, and then the powder press applies pressure to the upper punch 11 to dry-press the powder in the die hole 21 to form a ceramic shell blank. At the same time, the excess powder corresponding to the middle part of the ceramic shell blank will be squeezed out of the middle mold 2 through the powder overflow groove 22. After the molding is completed, the hole-forming core rod 5 is lowered and exited from the die hole 21 by the first driving cylinder, and then the middle mold 2 is moved upward by the second driving cylinder to complete the demolding and obtain the ceramic shell blank.

[0027] The ceramic shell blank obtained by dry pressing the mold of the invention is placed in a sintering furnace for sintering to obtain a ceramic shell A. The appearance of the ceramic shell A is as follows: Fig.11 As shown, the square is not deformed. The outer width of ceramic shell A is measured, and the data is shown in Table 1. The ceramic shell blank formed by dry pressing with a traditional mold is sintered to obtain ceramic shell B. The outer width of ceramic shell B is also measured, and the data is shown in Table 2.

[0028] The results show that the ceramic shell formed by dry pressing of the mold of the present invention is square and has no deformation after sintering, and its size meets the standard and has better consistency of size.

[0029] Table 1 External width of ceramic shell A

[0030] Table 2 External width of ceramic shell B

[0031] The above embodiments and drawings do not limit the product form and style of the present invention. Any appropriate changes or modifications made by ordinary technicians in the relevant technical field should be deemed to be within the patent scope of the present invention.

Claims

1. A ceramic shell forming die structure, comprising an upper punch, a middle die, a lower punch and a floating die, wherein a die hole is provided in the middle die, characterized in that: The middle die is provided with powder overflow grooves at positions on both sides corresponding to the die hole, each of which is arranged in the middle of the upper end of the middle die, and the upper end of each of the powder overflow grooves is open, the length of each of the powder overflow grooves is 5% to 15% of the length of the ceramic shell, the width of each of the powder overflow grooves is 2 to 3 mm, and the depth of each of the powder overflow grooves is 5% to 10% of the height of the ceramic shell. The upper punch is located above the die hole, and the lower punch is located in the die hole. A cavity for the floating punch to extend into is provided in the lower punch, and the upper end of the floating punch extends into the die hole from the upper end of the lower punch.

2. A ceramic shell forming mold structure according to claim 1, characterized in that: The powder overflow grooves are arranged symmetrically with respect to the center.

3. The ceramic shell forming mold structure according to claim 1, characterized in that: The root of the groove bottom of each of the powder overflow grooves is an arc surface with an R angle transition, and the radius of the arc surface is equal to the width of the powder overflow groove.

4. The ceramic shell forming mold structure according to claim 1, characterized in that: A plurality of through-channels are arranged in the floating punch die, and a hole-forming core rod is passed through each of the through-channels.

5. A ceramic shell forming mold structure according to claim 4, characterized in that: One end of each of the hole-forming mandrels extends into or out of the die hole, and the other end of each of the hole-forming mandrels is mounted on a mounting seat, and the mounting seat is connected to a mandrel driving assembly.

6. The ceramic shell forming mold structure according to claim 5, characterized in that: The core rod driving assembly is a first driving cylinder, and the piston rod of the first driving cylinder is connected to the mounting seat to drive each of the hole-forming core rods to move up and down.

7. The ceramic shell forming mold structure according to claim 4, characterized in that: The bottom of the upper punch die is provided with an upper punch which extends into the die hole and extrude powder into a mold. The extrusion surface of the upper punch die is provided with a plurality of slot holes which correspond to the through-channels and accommodate the corresponding ends of each of the hole-forming core rods.

8. The ceramic shell forming mold structure according to claim 1, characterized in that: The middle mold is connected with a middle mold driving component.

9. The ceramic shell forming mold structure according to claim 8, characterized in that: The middle mold driving assembly is a second driving cylinder, and a piston rod of the second driving cylinder is connected to the middle mold to drive the middle mold to move up and down.

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