Screw forming die for multi-layer nested annular hole grain

Abstract

The invention discloses a screw forming mold for a multi-layer nested annular hole grain. The screw forming mold comprises a rear cone, a front cone and a mold front section which form a mold cavity, a copper sleeve fixed to the outlet end of the mold cavity, and a combined mold needle assembly arranged in the mold cavity. The combined mold needle assembly comprises an inner mold needle assembly, a middle mold needle assembly and an outer mold needle assembly; the inner die needle assembly, the middle die needle assembly and the outer die needle assembly are sequentially arranged front and back, so that the inner wall of the copper sleeve, the outer die sleeve, the middle die sleeve and the inner die needle form a pressing molded surface matched with a multi-layer nested annular hole grain; the front needle frame of the inner mold needle assembly and the middle needle frame of the middle mold needle assembly are both fixed to the joint of the rear cone and the front cone, and the rear needle frame of the outer mold needle assembly is fixed to the front end of the copper sleeve. By means of the forming die, trial-manufacturing of the large-size isoplanar combustion multi-layer nested annular hole grain is achieved.

Description

Technical Field

[0001] The invention relates to a screw pressing forming die for a multi-layer nested annular hole medicine column, and belongs to the field of die design. Background Art

[0002] For a long time, the shape structure of screw-pressed propellants in China has been mainly simple tubular, cylindrical, and inner star hole loading, and the screw-pressed integrated molding of large-sized equal-surface combustion porous grain columns has not been achieved. The main reasons are that the temperature field, pressure field, velocity field, etc. in the screw-pressed molding process of complex charge are unclear, the mechanism of the coupling of material characteristics, mold structure, and process parameters on the molding quality is unclear, and the equipment is limited. In order to achieve the effect of large combustion surface, under the existing conditions, a compromise is adopted to form a brush-type charge structure by bonding and assembling multiple tubular charges in the later stage. Because the brush-type charge structure is assembled by bonding multiple charge columns, it requires more post-processing processes, including secondary heating, truncation, measurement, matching, and solidification operations, as well as moving and transporting between multiple processes. In particular, the solidification process is mostly manual, time-consuming, and requires high operating requirements for employees. The stability and consistency of the operation are directly related to the stability and consistency of the charge performance. In addition, the solidification process also has a high safety risk, and serious safety accidents caused by the friction of the plugging have occurred. Mold structure is one of the key factors affecting the forming of propellant grains, especially for complex charges. The mold structure is complex, such as flow channel compression ratio, mold hole layout, molding section aspect ratio, needle arrangement, diversion angle, etc., which will affect the flow field characteristics of the molding process, the pressure, temperature, shear rate, streamline distribution characteristics and extrusion expansion behavior in the die head. Unreasonable mold structure design will directly lead to the extruded grain not being formed, the molding is not dense, the molding is uneven, the torque is too high to extrude, or the screw press "slips". At present, although the brush-type charges formed by screw pressing and the large-sized equal-surface combustion porous charges formed by casting can meet the performance requirements of weapons and equipment at this stage, they are limited by their own process and structural deficiencies. They cannot meet the pressing of multi-layer nested annular hole grains. The cross-sectional diagram of the grain is shown in the figure. Figure 5 shown. Summary of the invention

[0003] The purpose of the present invention is to solve the trial production of large-sized equal-surface combustion multi-layer nested annular hole grains and to provide a screw pressing forming die for multi-layer nested annular hole grains.

[0004] The objective of the present invention is achieved through the following technical solutions:

[0005] The invention discloses a screw-pressing forming die for a multi-layer nested annular hole drug column, comprising a rear cone, a front cone and a front section of the die constituting a die cavity, and a copper sleeve fixed at the outlet end of the die cavity, characterized in that a combined die pin assembly is arranged in the die cavity;

[0006] The combined mold pin assembly comprises an inner mold pin assembly, a middle mold pin assembly and an outer mold pin assembly;

[0007] The inner mold needle assembly is composed of a front needle frame and an inner mold needle fixed to the middle of the front needle frame through a rib plate;

[0008] The middle mold needle assembly is composed of a middle needle frame and a middle mold sleeve, and the middle needle frame is composed of two coaxial annular frames, one large and one small. The large annular frame is connected to the small annular frame through a rib plate, and the small annular frame is connected to the middle mold sleeve through a conical frame.

[0009] The outer mold needle assembly is composed of a rear needle frame and an outer mold sleeve fixed to the middle of the rear needle frame through a rib plate;

[0010] The inner mold needle assembly, the middle mold needle assembly and the outer mold needle assembly are arranged front and back in sequence, so that the inner wall of the copper sleeve and the outer mold sleeve, the middle mold sleeve and the inner mold needle form a pressing surface that matches the multi-layer nested annular hole medicine column; the front needle frame of the inner mold needle assembly and the middle needle frame of the middle mold needle assembly are both fixed at the connection between the rear cone and the front cone, and the rear needle frame of the outer mold needle assembly is fixed on the front end of the copper sleeve.

[0011] The outer walls of the front needle frame and the middle needle frame are connected to the inner wall of the mold cavity through needle frame positioning keys, so that the combined mold needle assembly and the mold cavity maintain circumferential positioning.

[0012] The outer wall of the rear needle holder and the front outer wall of the copper sleeve are connected with the inner wall of the front section of the mold through a copper sleeve positioning key, so that the outer wall of the copper sleeve and the front section of the mold are kept in circumferential positioning.

[0013] Beneficial Effects

[0014] The molding die of the present invention realizes the trial production of large-sized equal-surface combustion multi-layer nested annular hole grains, and the test pieces are well formed and the sizes meet the requirements. It can provide a reference for subsequent large-sized equal-surface combustion special-shaped grains. Since the needle holder is reasonably designed, the screw pressure resistance is moderate, the flowability of the grain is good, the process temperature can be controlled according to the normal compression and stretching process of the propellant, and the load is within the normal range. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the screw forming mold of the present invention;

[0016] Figure 2 It is a schematic structural diagram of the inner mold pin assembly of the screw forming mold of the present invention;

[0017] Figure 3 It is a structural schematic diagram of the middle mold pin assembly of the screw forming mold of the present invention;

[0018] Figure 4It is a schematic structural diagram of the outer mold pin assembly of the screw forming mold of the present invention;

[0019] Figure 5 It is a cross-sectional view of a multi-layer nested annular hole charge;

[0020] In the figure, 1-inner mold needle assembly, 11-front needle holder, 12-inner mold needle, 2-middle mold needle assembly, 21-middle needle holder, 22-middle mold sleeve, 3-outer mold needle assembly, 31 rear needle holder, 32-outer mold sleeve, 4-mold front section, 5-copper sleeve, 6-front cone, 7-copper sleeve positioning key, 8-needle holder positioning key. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0022] Example

[0023] like Figure 1 As shown, a screw pressing molding die for a multi-layer nested annular hole drug column of the present invention comprises a rear cone, a front cone 6 and a front section 4 of the die constituting a die cavity, a copper sleeve 5 fixed at the outlet end of the die cavity, and a combined die pin assembly arranged in the die cavity;

[0024] The combined mold pin assembly comprises an inner mold pin assembly 1, a middle mold pin assembly 2 and an outer mold pin assembly 3;

[0025] like Figure 2 As shown, the inner mold needle assembly 1 is composed of a front needle frame 11 and an inner mold needle 12 fixed to the middle of the front needle frame through a rib plate;

[0026] like Figure 3 As shown, the middle mold needle assembly 2 is composed of a middle needle frame 21 and a middle mold sleeve 22. The middle needle frame 21 is composed of two coaxial annular frames, one large and one small. The large annular frame is connected to the small annular frame through a rib plate, and the small annular frame is connected to the middle mold sleeve 22 through a conical frame.

[0027] like Figure 4 As shown, the outer mold needle assembly 3 is composed of a rear needle frame 31 and an outer mold sleeve 32 fixed to the middle of the rear needle frame 31 through a rib plate;

[0028] The inner mold needle assembly 1, the middle mold needle assembly 2 and the outer mold needle assembly 2 are arranged front and back in sequence, so that the inner wall of the copper sleeve 5 and the outer mold sleeve 32, the middle mold sleeve 22 and the inner mold needle 12 form a pressing surface matching the multi-layer nested annular hole medicine column; the front needle frame 11 of the inner mold needle assembly 1 and the middle needle frame 21 of the middle mold needle assembly 2 are both fixed at the connection between the rear cone and the front cone 6, and the rear needle frame 31 of the outer mold needle assembly 2 is fixed at the front end of the copper sleeve 5.

[0029] The outer walls of the front needle frame 11 and the middle needle frame 21 are connected to the inner wall of the mold cavity via a needle frame positioning key 8, so that the combined mold needle assembly 2 and the mold cavity maintain circumferential positioning.

[0030] The outer wall of the rear needle holder 31 and the front outer wall of the copper sleeve 5 are connected with the inner wall of the front section 4 of the mold via a copper sleeve positioning key 7, so that the outer wall of the copper sleeve 5 and the front section 4 of the mold are kept in circumferential positioning.

Claims

1. A screw pressing mold for a multi-layer nested annular hole drug column, comprising a rear cone, a front cone and a front section of the mold constituting a mold cavity, and a copper sleeve fixed at the outlet end of the mold cavity, characterized in that: A combined mold pin assembly disposed in the mold cavity; The combined mold pin assembly comprises an inner mold pin assembly, a middle mold pin assembly and an outer mold pin assembly; The inner mold needle assembly is composed of a front needle frame and an inner mold needle fixed to the middle of the front needle frame through a rib plate; The middle mold needle assembly is composed of a middle needle frame and a middle mold sleeve, and the middle needle frame is composed of two coaxial annular frames, one large and one small. The large annular frame is connected to the small annular frame through a rib plate, and the small annular frame is connected to the middle mold sleeve through a conical frame. The outer mold needle assembly is composed of a rear needle frame and an outer mold sleeve fixed to the middle of the rear needle frame through a rib plate; The inner mold needle assembly, the middle mold needle assembly and the outer mold needle assembly are arranged front and back in sequence, so that the inner wall of the copper sleeve and the outer mold sleeve, the middle mold sleeve and the inner mold needle form a pressing surface that matches the multi-layer nested annular hole medicine column; the front needle frame of the inner mold needle assembly and the middle needle frame of the middle mold needle assembly are both fixed at the connection between the rear cone and the front cone, and the rear needle frame of the outer mold needle assembly is fixed on the front end of the copper sleeve.

2. A screw pressing forming die for a multi-layer nested annular hole drug column as claimed in claim 1, characterized in that: The outer walls of the front needle frame and the middle needle frame are connected to the inner wall of the mold cavity through needle frame positioning keys, so that the combined mold needle assembly and the mold cavity maintain circumferential positioning.

3. A screw pressing forming die for a multi-layer nested annular hole drug column as claimed in claim 1 or 2, characterized in that: The outer wall of the rear needle holder and the front end outer wall of the copper sleeve are connected with the inner wall of the front section of the mold through a copper sleeve positioning key, so that the outer wall of the copper sleeve and the front section of the mold are kept in circumferential positioning.

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