CN106704037B - A kind of missile propulsive plant band seam allowance locks underseal header structure - Google Patents

Abstract

The invention discloses a head structure with a bottom lock for a missile engine. The head structure with a bottom lock for a missile engine is welded by a hemisphere and a skirt with a bottom lock structure through electron beam welding. During electron beam welding, there is no need to install protective tooling between the bottom lock skirt and the hemisphere, and the gap between the two can be 0 in theory, which can make full use of the overall structural dimensions and increase the structural weight. less, the engine structure is more compact; in the case of strict control of the distance between the front and rear skirts, the charge space can be maximized, increasing the charge amount, which has a significant effect on increasing the total stroke of the engine and improving engine performance; at the same time, there is no need to customize the electron beam welding protective tooling, The cost is saved, the technological process is simplified, and the efficiency and reliability of the welding process are improved.

Description

Bottom-sealing structure with spigot and lock for missile engine

technical field

The invention relates to a solid rocket motor, in particular to a missile motor with a spigot-locked-bottom head structure.

Background technique

The head is one of the important parts in the shell of the missile engine combustion chamber. The hemisphere in the head structure bears the internal pressure generated by the combustion of the propellant, and the skirt is used for the connection between cabins or with other components, and it must bear the axial pressure , bending moment, shear and other loads, the force situation is more complicated. Therefore, the hemisphere and the skirt in the head structure are required to have high connection strength and rigidity.

The hemisphere and the skirt are usually welded by electron beam welding or argon arc welding, and the weld seam is a place that is prone to damage. Due to the complex stress of the head, there is a high requirement for the strength of the weld seam. The electron beam welding energy is high, the weld width is small, the heat affected zone is small, the mechanical properties of the welded joint are high, and the strength of the welded joint can be as strong as that of the base metal. Therefore, the structural strength and rigidity of the head welded by electron beam welding can meet the requirements of various internal pressure and external loads of the missile engine.

Figure 1 is a schematic diagram of the structure of a conventional engine head. When the conventional head structure is welded by electron beams, protective tooling needs to be added between the skirt and the hemisphere to protect the hemisphere from being damaged by the electron beam. Therefore, it is required that the minimum gap between the skirt and the hemisphere is greater than 3mm. In the case of strictly controlled axial dimensions such as the distance between the front and rear skirts, the gap between the skirt and the hemisphere will reduce the amount of charge and affect the total stroke of the engine, which cannot meet the overall requirements for the axial size and charge of the engine. In addition, the protective tooling is assembled by multi-sections of copper sheets. During the electron beam welding process, the welding tooling may be displaced due to gaps, so that the protective tooling cannot play a protective role. It can be seen that the protective tooling is not very reliable.

Contents of the invention

In order to solve the above problems, the present invention provides a missile engine head structure with a spigot and a bottom lock, which includes a hemisphere and a skirt with a spigot and a bottom lock structure. The bottom lock structure skirt with a stop has a ring-shaped bottom lock structure in the circumferential direction, the skirt with a bottom lock structure is connected to the hemisphere by electron beam welding, and the bottom lock structure replaces the protective tooling to protect the hemisphere The body is not damaged by the electron beam in the electron beam welding, so the gap between the skirt and the hemisphere can be zero theoretically.

Further, the material of the skirt with a bottom lock structure is 20CrMnTi, and the skirt with a bottom lock structure has a circular ring-shaped bottom lock structure along the circumferential direction, the length of the bottom lock is 2mm, and the wall thickness is 1.5mm. The inner diameter of the mouth lock bottom is Ф389.2mm, and the outer diameter is Ф392.2mm.

Further, the structural material of the hemisphere is 30Cr3SiNiMoVA(Z), there are steps on the hemisphere for electron beam welding with the skirt, and there are 32 M10 threaded holes on the end surface of the hemisphere for connecting with the tailpipe.

Compared with the conventional engine head structure, the present invention has advantages and beneficial effects as follows:

1) The axial gap between the skirt and the hemisphere in the head structure with a bottom lock with a seam can theoretically be 0, which can make full use of the overall size of the overall structure and make the engine structure more compact; the distance between the front and rear skirts In the case of strict control, the charging space can be maximized, increasing the amount of charge, improving the total stroke of the engine; improving engine performance;

2) There is no need to customize protective tooling, which saves costs; on the premise of determining the structure of the free-loading charge, the process is simplified and the assembly efficiency is improved;

3) The structural reliability of the bottom head with spigot lock is higher than that of the protective tooling, which can ensure that the hemisphere will not be damaged during electron beam welding.

Description of drawings

The technical solution of the present invention will be described below through specific embodiments.

Fig. 1 is the schematic diagram of conventional missile engine head structure;

Fig. 2 is a schematic diagram of the structure of the missile engine with a stopper and a bottom lock provided by the implementation of the present invention.

Detailed ways

Hereinafter, the present invention will be further described in conjunction with the drawings and embodiments.

As shown in FIG. 2 , it is a schematic diagram of the structure of the rear head of the missile engine with a spigot and a bottom lock provided by the present invention. The rear head of the combustion chamber housing of the engine adopts the structural form of a head with a spigot and a bottom lock, including: a rear hemisphere 1, and a rear skirt 2 with a spigot and a bottom lock structure. The structure of the head with spigot and bottom lock is connected by electron beam welding to ensure that the structure of the head has sufficient strength and rigidity. The back skirt 2 with a stop lock bottom structure has a ring-shaped stop lock bottom, which is used to protect the hemisphere from being damaged by the electron beam during electron beam welding, so as to complete the welding of the head to ensure The head has sufficient strength and rigidity.

The rear hemisphere 1 is processed in the form of integral forging. Compared with segmental stamping, the overall forging of the rear hemisphere has higher rigidity and strength, and better manufacturability. deformation is smaller. At the same time, there are 32 M10 threaded holes on the end face of the rear hemisphere, which are used to connect with the tail pipe.

The rear skirt 2 with the bottom lock structure has a ring-shaped bottom lock, which can replace the protective tooling and protect the rear hemisphere from damage during electron beam welding. At the same time, there are 8 φ8. 5 threaded holes and a φ8 pin hole for docking with the steering gear cabin.

In addition, the outer diameter of the rear skirt with the bottom lock structure is the same as that of the rear hemisphere. Both the rear skirt with the bottom lock structure and the rear hemisphere have steps for electron beam welding. The straight line section for welding on the steps is 5.6mm. The depth of the weld seam after electron beam welding should be greater than or equal to 5.5mm, and the inner surface of the bottom of the spigot lock must not be penetrated. There is a transitional arc R0.3 at the root of the rear skirt with spigot lock bottom structure 2 spigot lock bottom, so that there is a certain gap between the two. This gap is conducive to the overflow of metal vapor and impurity gases generated during the welding process to avoid Dense stomata.

According to the general issued mechanical interface coordination and size requirements, determine the structural size of the butt section of the combustion chamber shell. If a conventional missile engine head structure is used as shown in Figure 1, it is necessary to install protective tooling between the skirt and the hemisphere during electron beam welding to protect the hemisphere from being damaged by the electron beam, so it requires the skirt and hemisphere There is a gap of not less than 3mm between the bodies for the installation of protective tooling. At the same time, there are strict requirements on the axial size of the combustion chamber shell. Generally, the distance between the front and rear skirts is a fixed value. Due to the existence of the gap, the axial distance of the charge section will be shortened, the charge amount will be reduced, and the engine performance will be reduced. The ring-shaped bottom locking structure of the rear skirt with the locking bottom structure of the present invention can be used as a protective tool, because there is no need to install additional protective tooling, the gap between the skirt and the hemisphere can be zero in theory. If both the front and rear heads adopt the structure of the head with spigot and bottom lock, the axial length of the charge section can be increased by about 6mm, the charge amount can be increased, the engine performance can be improved, the process can be simplified, the cost can be saved, and the overall requirement for the axial size can be met. .

Taking the engine with a diameter of 400mm as an example, the outer diameter of the shell and the size of the front and rear joints are determined according to the overall mechanical coordination requirements. In the case of strict control of the axial size, the rear head adopts the structure of the bottom head with a stopper lock. The material of the rear skirt with the lock bottom structure is 20CrMnTi, the length of the lock bottom is 2mm, and the wall thickness is 1.5mm, which is used to protect the rear hemisphere from being damaged by the electron beam. The outer diameters of the rear hemisphere and the rear skirt with a seam-locked bottom structure are both 400mm, and the straight line section of the two for electron beam welding is 5.6mm, and the weld depth after electron beam welding is greater than or equal to 5.5mm, and the seam lock The inner surface of the bottom shall not be welded through. There is a gap of 0.3mm between the rear hemisphere and the rear skirt of the locking bottom structure, which is conducive to the overflow of metal vapor and impurity gases generated during the welding process and avoids dense air holes.

This structure has been applied in a certain model, and the manufacturability and producibility of the product have been verified, and it has passed the stress-strain test, hydraulic test, blasting test and projectile static test under the combined action of internal pressure and external load, and the structure is reliable , meeting the general requirements.

Claims (5)

1. A missile engine band spigot lock bottom head structure, is characterized in that: comprise band spigot lock bottom structure skirt and hemisphere; Described belt slit bottom lock structure skirt and hemisphere adopt vacuum electron beam welding; There is a ring-shaped bottom lock structure on the skirt of the bottom lock structure with a stop, and the bottom lock structure can protect the hemisphere from being damaged during the vacuum electron beam welding process. 2. The head structure of missile engine with stop lock and bottom lock as claimed in claim 1, characterized in that: the skirt material of the belt stop lock bottom structure is 20CrMnTi, the stop lock bottom structure is a section of ring, and the stop lock The bottom length is 2mm and the wall thickness is 1.5mm. 3. The structure of the missile engine with a spigot and a bottom lock as claimed in claim 2, characterized in that: the skirt end face of the structure with a spigot and a bottom lock has 8 threaded holes of φ8.5 and a pin hole of φ8. For docking with other compartments. 4. missile engine band spigot lock bottom head structure as claimed in claim 1, is characterized in that: described hemispherical body material is 30Cr3SiNiMoVA (Z), and there are 32 threaded holes of M10 on the hemispherical body end face, are used for and Tail pipe connection. 5. The missile engine head structure with a bottom lock and a bottom lock as claimed in claim 1, characterized in that: the structure skirt with a bottom lock with a stop and the outer diameter of the hemisphere are the same, and the structure skirt with a bottom lock with a stop and the hemisphere have the same diameter. There is a boss used for welding, the straight line section is 5.6mm, the depth of the weld after welding is ≥5.5mm, and the inner surface of the bottom of the spigot lock must not be penetrated.