Fastener-free umbrella disc core mold and assembling method

Abstract

The invention relates to the technical field of grain core mold forming, in particular to a fastener-free loose disc core mold and an assembling method. The umbrella disc core mold comprises a pressing sleeve, a wing fixing sleeve, a front wing plate, an umbrella disc assembly and a main core rod, wherein the front wing plate and the wing fixing sleeve are connected and limited through a bolt and a pin; the umbrella disc assembly is axially divided into two layers and comprises a first-layer umbrella disc and a second-layer umbrella disc, and the axial layering size of the second-layer umbrella disc meets the demolding space size of the first-layer umbrella disc; a straight umbrella block in a first-layer umbrella tray in the umbrella tray assembly is placed on the front wing plate, other inclined umbrella blocks and the straight umbrella block are positioned in a positioning fit mode, and the first-layer umbrella tray is completely pressed through a pressing sleeve; and the second layer of umbrella disc is annularly positioned with the first layer of umbrella disc through a conical surface and is axially pressed through the main core rod. The assembling and demolding efficiency is improved by three times, and the safety and reliability are improved; if explosive seepage occurs in the explosive charging process, the safety risk of dismounting the bolt and the taper pin is high, and the bolt and the pin are omitted to completely eradicate the potential safety hazard.

Description

Technical Field

[0001] The present invention relates to the technical field of core mold forming of a charge column, and in particular to a core mold for an umbrella disc without fasteners and an assembly method thereof. Background Art

[0002] Maintaining structural integrity in high-M-number grain designs for solid rocket engines presents a design challenge, particularly at low temperatures. Limited domestic process technology and propellant materials currently limit the ability to achieve stress relief in grains. While the parachute core mold is a crucial technology for achieving stress relief in high-M-number grains, limited domestic research is available, and even fewer references are available.

[0003] A composite core mold, currently published with the publication number CN107434754B, provides the first detailed description of the core mold design for a parachute disc. The core mold consists of two layers of parachute discs, each with several straight and slanted segments. Each segment in the first layer is connected and secured to a retaining sleeve via two bolts and two conical pins. The second layer is positioned relative to the first layer using conical surfaces and steps, and a compression sleeve secures all segments in the second layer. This structure, used in many models, effectively fills a gap in parachute disc design. A detachable parachute disc, published with the publication number CN107524545A, features a structure consisting of three alternately connected segments A and B, forming a circular table. The table has axial through-holes that mate with the core mold. Segments A and B are bonded to the charge core mold; both segments are made of polytetrafluoroethylene. The reliability of this parachute disk core mold bonding process is not high. If the parachute block loosens or shifts during the loading process, the entire engine will be scrapped.

[0004] However, as the production tasks of engine propellants become increasingly heavy and the number of high-energy formula propellants increases, the disadvantages of this type of structure, which uses bolts and pins to connect and position the umbrella disc, are low in efficiency in assembly and disassembly, high risk of demolding safety when leakage occurs, and difficulty in achieving automation, are becoming increasingly obvious. Therefore, a new type of efficient and reliable umbrella disc core mold structure is needed. Summary of the Invention

[0005] Based on the above technical problems, the present invention proposes a fastener-free umbrella disk core mold and assembly method to solve the problems of the existing umbrella disk core mold of the formed annular grooved charge having a large number of bolts and conical pins, low assembly and disassembly efficiency, high demolding risk, and difficulty in achieving automated assembly and demolding.

[0006] In order to solve the above technical problems, one of the objects of the present invention is to provide a fastener-free umbrella disc core mold, including a pressing sleeve 1, a wing fixing sleeve 2, a front wing panel 3, an umbrella disc assembly 4 and a main core rod 5, wherein the front wing panel 3 and the wing fixing sleeve 2 are connected and limited by bolts and pins; the umbrella disc assembly 4 is axially divided into two layers, including a first layer of umbrella disc and a second layer of umbrella disc, and the axial layering size of the second layer of umbrella disc meets the demolding space size of the first layer of umbrella disc; the straight umbrella blocks in the first layer of umbrella disc in the umbrella disc assembly 4 are placed on the front wing panel 3, and the remaining oblique umbrella blocks are positioned with the straight umbrella blocks through positioning cooperation, and the first layer of umbrella disc is completely pressed by the pressing sleeve 1; the second layer of umbrella disc is circumferentially positioned with the first layer of umbrella disc through a conical surface, and is axially pressed by the main core rod 5.

[0007] Furthermore, the first layer of umbrella plate is composed of straight umbrella blocks and oblique umbrella blocks, the straight umbrella blocks are clearance-matched with the oblique umbrella blocks, the straight umbrella blocks are provided with positioning steps, and the oblique umbrella blocks are provided with corresponding positioning grooves. The number of straight umbrella blocks in the first layer of umbrella plate is the same as the number of front wing panels, and the number of oblique umbrella blocks is consistent with that of straight umbrella blocks.

[0008] Furthermore, the first layer of umbrella plate blocks includes six straight umbrella blocks and six oblique umbrella blocks.

[0009] Furthermore, the first layer of umbrella blocks (4) and the umbrella fixing sleeve (2) are realized by providing a 20° trapezoidal structure groove on the umbrella block and a similar 20° trapezoidal structure boss on the umbrella fixing sleeve, which facilitates installation and demoulding.

[0010] Furthermore, the second layer of umbrella plate is composed of four straight umbrella blocks, four oblique umbrella blocks I and four oblique umbrella blocks II.

[0011] Furthermore, the inner surface of the second layer of the umbrella disk is provided with a positioning step to cooperate with the main core rod (5), and a dovetail groove is provided to press it through the main core rod.

[0012] Furthermore, a step is provided on the first layer of umbrella disc for fixing with the compression sleeve, so that the first layer of umbrella blocks is fixed when the second layer of umbrella disc is assembled.

[0013] Furthermore, both the first layer of umbrella discs and the second layer of umbrella discs are provided with conical surface matching limiters, and end surface supports are provided in the middle.

[0014] Furthermore, all mating surfaces are provided with sealing grooves to prevent drug leakage.

[0015] Based on the same inventive concept, the present invention also provides a method for assembling a fastener-free umbrella disk core mold, comprising the following steps:

[0016] 1) Place the first layer of six straight umbrella blocks on the front wing plate and use the grooves on the umbrella blocks and the wing fixing sleeves to limit the position;

[0017] 2) Place the six oblique parachute blocks on the steps of the straight parachute blocks in sequence. After all are in place, lower the front wing fixing sleeve, front wing plate and the first layer of parachute disc axially to the front opening of the engine casing, and use the pressing sleeve to press the first layer of parachute disc tightly.

[0018] 3) Install the second layer of umbrella plates in sequence. The umbrella blocks in the second layer of umbrella plates have no positional correspondence with the umbrella blocks in the first layer of umbrella plates, and can be spliced at will.

[0019] The above-mentioned one or more technical solutions of the present invention have at least one or more of the following technical effects: the present invention triples the efficiency of assembly and demoulding; the operator directly places the umbrella block without the need to tighten the bolts and install the conical pins, and the assembly and demoulding efficiency is significantly improved; the safety and reliability of the present invention are improved; if drug leakage occurs during the charging process, the safety risk of disassembling the bolts and conical pins is high; the elimination of bolts and pins completely eliminates this safety hazard. The present invention reduces the difficulty of achieving automated assembly and demoulding; the automatic installation or removal of bolts and conical pins in a confined space is very difficult and the cost is also extremely high. This solution eliminates the bolts and conical pins to clear the way for the subsequent automated assembly and demoulding. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 : Schematic diagram of the structure of the umbrella disk core mold without fasteners of the present invention;

[0021] Figure 2 : Schematic diagram of the umbrella disc assembly structure;

[0022] Figure 3 : Schematic diagram of the positioning structure of the first layer of umbrella plate and umbrella blocks;

[0023] Figure 4 : Schematic diagram of the umbrella fixing sleeve structure;

[0024] Figure 5 : Schematic diagram of the first and second layer umbrella plates’ limit positions;

[0025] Figure 6 : Schematic diagram of the second layer of umbrella plate pressing steps;

[0026] Figure 7 : Schematic diagram of the first layer of umbrella plate pressing steps;

[0027] Figure 8 : Schematic diagram of the first layer of oblique umbrella blocks;

[0028] Figure 9 : Schematic diagram of the first layer of straight umbrella blocks;

[0029] Figure 10 : Schematic diagram of the first layer of umbrella plate combination;

[0030] Figure 11 : Schematic diagram of demoulding the second layer of umbrella plate straight umbrella block;

[0031] Figure 12 : Schematic diagram of demoulding the second layer of umbrella plate oblique umbrella blocks;

[0032] Figure 13 : Schematic diagram of the first layer of umbrella blocks;

[0033] Figure 14 : Schematic diagram of the demoulding hole of the umbrella block;

[0034] Figure 15 : Schematic diagram of demoulding the first layer of umbrella plate;

[0035] Figure 16 : Actual picture of the first layer of umbrella plate;

[0036] Figure 17 : Actual picture of the second layer umbrella plate;

[0037] Figure 18 : Actual assembly diagram of the oblique umbrella block and the straight umbrella block of the first layer of umbrella tray;

[0038] Among them: 1-pressing sleeve, 2-wing fixing sleeve, 3-front wing plate, 4-umbrella disc assembly, 41-first layer umbrella disc, 42-second layer umbrella disc, 5-main core rod, 6-matching cone surface, 7-end face support, 8-pressing end face, 9-dovetail groove on umbrella block, 10-core rod positioning step, 11-dovetail groove on core rod, 12-positioning groove, 13-positioning step, 14-oblique umbrella block I, 15 oblique umbrella block II, 16-draft taper, 17-demolding hole. Specific implementation plan

[0039] The present invention mainly solves the problems of too many bolts and conical pins in the core mold of the umbrella disc for forming annular grooved charge, low assembly and disassembly efficiency, high demoulding risk, and great difficulty in realizing automated assembly and demoulding. The present invention provides a new type of umbrella disc core mold structure that is efficient and reliable. The umbrella disc core mold includes a pressing sleeve, a wing fixing sleeve, a front wing plate, an umbrella disc assembly and a main core rod. The front wing plate and the wing fixing sleeve are connected and limited by bolts and pins; the umbrella disc assembly is axially divided into two layers, including a first layer of umbrella disc and a second layer of umbrella disc, and the axial layered size of the second layer of umbrella disc meets the demoulding space size of the first layer of umbrella disc; the straight umbrella blocks in the first layer of umbrella disc in the umbrella disc assembly fall on the front wing plate, and the remaining oblique umbrella blocks are positioned with the straight umbrella blocks through positioning cooperation, and the first layer of umbrella disc is completely pressed by the pressing sleeve; the second layer of umbrella disc is circumferentially positioned with the first layer of umbrella disc through the conical surface and axially pressed by the main core rod.

[0040] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments obtained. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present invention.

[0041] The overall technical solution consists of a compression sleeve 1, a wing fixing sleeve 2, a front wing panel 3, an umbrella disc assembly 4, and a main core rod 5. The front wing panel 3 and the wing fixing sleeve are connected and limited by bolts and pins; the six straight umbrella blocks in the first layer of the umbrella disc in the umbrella disc 4 are placed on the front wing panel 3, and the remaining six oblique umbrella blocks are positioned with the straight umbrella blocks through positioning cooperation, and finally the first layer of the umbrella disc is completely compressed by the compression sleeve 1. The second layer of umbrella disc is positioned circumferentially with the first layer of umbrella disc through a conical surface and compressed axially by the main core rod 5. The umbrella disc is divided into two layers axially, and the axial layered dimensions of the second layer of umbrella disc meet the demolding space dimensions of the first layer of umbrella disc. The six straight umbrella blocks in the first layer of umbrella disc are placed on the wing panel, and at the same time, all the umbrella blocks of the first layer are positioned with the umbrella fixing sleeve through grooves, and the remaining six oblique umbrella blocks are set with step limits with the straight umbrella blocks. The outer cylindrical surface of the second layer of umbrella disc is fixed with the first layer of umbrella disc through a conical surface, and an end face support is set in the middle and finally it is compressed by the main core rod. Sealing grooves are set on all mating surfaces to prevent drug leakage. See the schematic diagram of the umbrella disc structure. Figure 1 .

[0042] See the diagram of the umbrella tray assembly Figure 2 As shown, the umbrella disc is axially layered. Considering the operating space and demoulding process, the umbrella disc is divided into two layers along the axial direction. The first layer of umbrella disc 41 is closer to the front wing, and the second layer of umbrella disc 42 is closer. The axial dimensions of the second layer of umbrella disc are larger than those of the first layer.

[0043] The umbrella blocks are limited and fixed, and the original screws, conical pins and other fasteners are cancelled. All the umbrella blocks and umbrella fixing sleeves of the first layer of umbrella tray are positioned by steps. Figure 3 As shown, considering the feasibility of assembly and demoulding, the positioning step of the umbrella fixing sleeve is set with a 20° draft taper. The schematic diagram of the umbrella fixing sleeve structure is shown in Figure 4 shown.

[0044] Conical surfaces are set on both layers of umbrella plates to match the limit, and end supports are set in the middle. Figure 5 As shown. After the first layer of umbrella blocks is dropped into place, the second layer of umbrella blocks is dropped and positioned radially and on the outer end surface of the first layer of umbrella blocks by the tapered surface 6. Meanwhile, the inner end surface of the second layer of umbrella blocks is supported by the 7 near the center end. Once all the second layer of umbrella blocks are in place, the first layer of umbrella discs is compressed by the 8 to secure it.

[0045] The inner surface of the second layer of umbrella block is provided with a positioning step to match the main core rod, and a dovetail groove is provided to press it tightly through the main core rod. Figure 6 The dovetail groove 9 on the umbrella block, the core rod positioning step 10, and the core rod matching surface are set as follows Figure 7 As shown, there is a core rod positioning step 10 and a dovetail groove 11 on the core rod.

[0046] In order to facilitate demoulding, auxiliary demoulding holes 17 are set on all umbrella blocks. Figure 14 .

[0047] The engine's fastener-free parachute disk structure is optimized and designed. The schematic diagram of the first layer of oblique parachute blocks is as follows: Figure 8 As shown, the corresponding positioning groove 12 is set on the inclined umbrella block. The first layer of straight umbrella block schematic diagram is as follows Figure 9 As shown, the straight umbrella block is provided on the positioning step 13, and the first layer of the umbrella plate straight umbrella block and the inclined umbrella block are assembled as shown in the actual figure. Figure 18 The first layer of umbrella plate oblique umbrella block and straight umbrella block fit in place schematic diagram is shown in Figure 10 shown.

[0048] The umbrella plate is divided into blocks in an annular direction. Under the premise of meeting the assembly and demoulding processes, the number of straight umbrella blocks in the first layer of umbrella plate is the same as the number of front wing panels, and the number of oblique umbrella blocks is consistent with the straight umbrella blocks. Therefore, the final structure of the first layer of umbrella blocks is six straight umbrella blocks + six oblique umbrella blocks. The actual picture of the first layer of umbrella plate is as follows Figure 16 As shown, the second layer is easy to operate, and the weight of a single umbrella block cannot be too large. For this reason, it is divided into four straight umbrella blocks + four oblique umbrella blocks I + four oblique umbrella blocks II. The actual picture of the second layer umbrella plate is as follows Figure 17 shown.

[0049] Assembling the chute: First, place the six straight chute blocks on the front wing panel, using the grooves on the blocks and the wing mounting sleeves to position them. Then, place the six inclined chute blocks sequentially on the steps of the straight chute blocks. Once all are in place, lower the front wing mounting sleeve, front wing panel, and first-layer chute disk axially into the front opening of the engine housing. Use the compression sleeve to tighten the first-layer chute disk. Then, install the second-layer chute disk in sequence. The blocks in the second-layer chute do not correspond to the blocks in the first layer; they can be assembled freely.

[0050] When demoulding, first remove any straight parachute block in the second layer of parachute disk along the center of the engine, and then remove the straight parachute block from the tail opening along the grain channel. The demoulding diagram of the second layer of parachute disk straight parachute block is as follows: Figure 11 Finally, remove the oblique umbrella block I and oblique umbrella block II in sequence. The schematic diagram of the second layer of umbrella plate oblique umbrella block demoulding is as shown in the figure below. Figure 12 shown.

[0051] In order to ensure that the second layer of umbrella blocks can be smoothly removed, a draft taper of 16 is set along the center demoulding direction when designing the second layer of umbrella blocks to ensure that after the lower end of the second layer of umbrella blocks is removed, the upper end can be removed smoothly. The schematic diagram of the first layer of umbrella blocks is as follows Figure 13 shown.

[0052] To demould the layer parachute blocks, first move the oblique parachute block toward the tail opening of the engine. After all of them are detached from the wing fixing sleeve, move the parachute block toward the center of the engine. Complete the demoulding of the six oblique parachute blocks in sequence, and then use the same method to demould the remaining six straight parachute blocks. The schematic diagram of the demoulding of the first layer of parachute disc is shown as follows: Figure 15 shown.

[0053] Obviously, those skilled in the art may make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. Thus, if such changes and modifications of the embodiments of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include such changes and modifications.

[0054] The present invention has been used in the design of core molds for parachute disks of multiple models of engines, and has passed the charge test and achieved the expected effect.

Claims

1. A core mold for an umbrella plate without fasteners, characterized in that: It includes a compression sleeve (1), a wing fixing sleeve (2), a front wing plate (3), an umbrella plate assembly (4) and a main core rod (5). The front wing plate (3) and the wing fixing sleeve (2) are connected and limited by bolts and pins; The umbrella disc assembly (4) is axially divided into two layers, including a first layer of umbrella discs and a second layer of umbrella discs, and the axial layered dimensions of the second layer of umbrella discs meet the demoulding space dimensions of the first layer of umbrella discs; The straight umbrella blocks in the first layer of umbrella discs in the umbrella disc assembly (4) are placed on the front wing plate (3), and the remaining inclined umbrella blocks are positioned with the straight umbrella blocks through positioning cooperation, and the first layer of umbrella discs are all compressed by the compression sleeve (1); the second layer of umbrella discs are circumferentially positioned with the first layer of umbrella discs through the conical surface and axially compressed by the main core rod (5).

2. The fastener-free umbrella disk core mold according to claim 1, characterized in that: The first layer of umbrella plate is composed of straight umbrella blocks and oblique umbrella blocks. The straight umbrella blocks are clearance-matched with the oblique umbrella blocks. The straight umbrella blocks are provided with positioning steps, and the oblique umbrella blocks are provided with corresponding positioning grooves. The number of straight umbrella blocks in the first layer of umbrella plate is the same as the number of front wing panels, and the number of oblique umbrella blocks is consistent with that of straight umbrella blocks.

3. The fastener-free umbrella disk core mold according to claim 2, characterized in that: The first layer of umbrella plate blocks includes six straight umbrella blocks and six oblique umbrella blocks.

4. The fastener-free umbrella disk core mold according to claim 1, characterized in that: The first layer of umbrella blocks (4) and the umbrella fixing sleeve (2) are realized by arranging a 20° trapezoidal structure groove on the umbrella block and arranging a similar 20° trapezoidal structure boss on the umbrella fixing sleeve, which facilitates installation and demoulding.

5. The fastener-free umbrella disk core mold according to claim 3, characterized in that: The second layer of umbrella plate consists of four straight umbrella blocks, four oblique umbrella blocks I and four oblique umbrella blocks II.

6. The fastener-free umbrella disk core mold according to claim 1, characterized in that: The inner profile of the second layer umbrella disc is provided with a positioning step to cooperate with the main core rod (5), and a dovetail groove is provided to press the main core rod tightly.

7. The fastener-free umbrella disk core mold according to claim 2, characterized in that: A step is provided on the first layer of umbrella disc for fixing with the compression sleeve, so that the first layer of umbrella blocks is fixed when the second layer of umbrella disc is assembled.

8. The fastener-free umbrella disk core mold according to any one of claim 7, characterized in that: The first layer of umbrella discs and the second layer of umbrella discs are both provided with conical surface matching limiters, and an end surface support is provided in the middle.

9. The fastener-free umbrella disk core mold according to claim 8, characterized in that: All mating surfaces are provided with sealing grooves to prevent drug leakage.

10. The method for assembling a fastener-free umbrella disk core mold according to any one of claims 1 to 9, characterized in that: The steps are as follows: 1) Place the first layer of six straight umbrella blocks on the front wing plate and use the grooves on the umbrella blocks and the wing fixing sleeves to limit the position; 2) Place the six oblique parachute blocks on the steps of the straight parachute blocks in sequence. After all are in place, lower the front wing fixing sleeve, front wing plate and the first layer of parachute disc axially to the front opening of the engine casing, and use the pressing sleeve to press the first layer of parachute disc tightly. 3) Install the second layer of umbrella plates in sequence. The umbrella blocks in the second layer of umbrella plates have no positional correspondence with the umbrella blocks in the first layer of umbrella plates, and can be spliced at will.

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