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CN-116423258-B - Positioning fixture for milling grooves in inner bottom of liquid rocket engine and machining and assembling method of positioning fixture

CN116423258BCN 116423258 BCN116423258 BCN 116423258BCN-116423258-B

Abstract

The invention provides a positioning fixture for milling grooves in an inner bottom of a liquid rocket engine and a processing and assembling method thereof, and belongs to the technical field of mechanical processing. The method comprises the steps of installing a workpiece into a carcass, enabling the bottom of an inner hole of the workpiece to be in contact with the top surface of the appearance of the carcass, positioning the workpiece and the carcass in a circumferential direction through a positioning pin and a positioning cover plate, enabling a locking bolt to penetrate through the workpiece and be in threaded connection with the carcass, enabling the workpiece to be tightly attached to the carcass through axial locking force, and carrying out milling groove processing on the workpiece after clamping. After the workpiece is machined, the long locating pin is taken out, the short locating pin is matched with the locating cover plate through the shaft hole to be connected with the workpiece, the locking bolt is loosened and taken out, the workpiece is rotated to enable the locking threaded hole of the locating cover plate to coincide with the threaded hole of the hoisting block, the hoisting ring is pulled up, the workpiece generates reverse motion perpendicular to the workbench of the machine tool, and the product is separated from the carcass. The invention has the advantages of accurate and reliable positioning, complete functions, convenient operation, small weight, safety and reliability.

Inventors

  • LI QIANG
  • LIU HE
  • HE XIAOHU
  • ZHANG TAO
  • YAO BO
  • YAN CHENGHAO
  • LIU CHAOZHI

Assignees

  • 西安航天发动机有限公司

Dates

Publication Date
20260508
Application Date
20230421

Claims (9)

  1. 1. The positioning fixture for the milling groove in the inner bottom of the liquid rocket engine is characterized by comprising a milling groove tool, wherein the milling groove tool comprises a positioning cover plate (1), a carcass (2), a positioning shaft (3), a nut (4), a compression bolt (5), a locking bolt (6), a long positioning pin (7) and a hoisting tool; The positioning shaft (3) is positioned at the lower end of the carcass (2) and is coaxially connected with the carcass (2), the positioning shaft (3) is used for positioning the carcass (2) on a machine tool workbench through shaft hole matching, the carcass (2) and the machine tool workbench are locked and fixed with a nut (4) through a compression bolt (5), the outer surface of the carcass (2) is matched with the inner surface of a workpiece, the workpiece is sleeved at the upper end of the carcass (2), the positioning cover plate (1) is pressed above the workpiece, positioning holes are formed in the corresponding positions of the positioning cover plate (1), the carcass (2) and the workpiece, a long positioning pin (7) is inserted into the positioning holes from top to bottom and is used for positioning the relative positions of the workpiece, the carcass (2) and the positioning cover plate (1), so as to prevent the workpiece from generating circumferential rotation, the positioning cover plate (1), the carcass (2) and the corresponding positions of the workpiece are provided with locking holes, and the locking bolt (6) is inserted into the locking threaded holes from top to bottom, and sequentially penetrates through the positioning cover plate (1), the workpiece and the carcass (2) to be screwed and tightly connected, so that an axial locking force is generated to enable the workpiece to be tightly attached to the carcass (2) to prevent axial movement of the workpiece; The hoisting tool comprises a hoisting block (8), a connecting bolt (9), a short positioning pin (10) and a hoisting ring (11); The hoisting block (8) is placed in a hoisting rectangular groove at the top of the carcass (2), and a threaded hole structure is arranged in the center of the hoisting block (8); The connecting bolt (9) is used for penetrating through a locking threaded hole of the positioning cover plate (1) to be connected with an inner threaded hole of the hoisting block (8); The short positioning pin (10) is used for connecting the positioning cover plate (1) with a workpiece through shaft hole matching, so that the workpiece and the positioning cover plate (1) can rotate together relative to the carcass; The lower end of the lifting ring (11) is provided with external threads, and the center of the top of the positioning cover plate (1) is provided with a lifting threaded hole; The lifting ring (11) is fixedly connected with the lifting threaded hole of the positioning cover plate (1) in a matching way.
  2. 2. The positioning fixture for milling grooves in a liquid rocket engine according to claim 1, wherein a gap of 0.05 mm-0.1 mm is formed between the carcass (2) and a workpiece to be processed.
  3. 3. A positioning fixture for milling grooves in a liquid rocket engine according to claim 1, wherein the outer circle runout of the carcass (2) is not more than 0.02mm.
  4. 4. A positioning fixture for milling grooves in a liquid rocket engine according to claim 1, wherein the flatness of the outer circle of the top surface of the carcass (2) is not more than 0.05mm.
  5. 5. The positioning fixture for milling grooves in the liquid rocket engine bottom is characterized in that the bottom of the carcass (2) is of a disc structure, a plurality of open grooves are formed in the side face of the disc, and the carcass (2) can be locked and fixed with nuts (4) through the open grooves in different positions and machine tool tables in different types through compression bolts (5).
  6. 6. The positioning fixture for milling grooves in a liquid rocket engine according to claim 1 is characterized in that the number of the locking threaded holes is 4, and the locking threaded holes are uniformly distributed on the top surface of a carcass (2) on the same circumference.
  7. 7. The positioning fixture for milling grooves in a liquid rocket engine according to claim 1, wherein the number of the hoisting rectangular grooves is 4, and the hoisting rectangular grooves and the locking threaded holes are uniformly distributed at 45 degrees on the same circumference.
  8. 8. The positioning fixture for milling grooves in a liquid rocket engine according to claim 1 is characterized in that two positioning holes are formed in the carcass (2), are distributed on a concentric circle with the locking threaded holes, and are symmetrically distributed relative to the center of a circle.
  9. 9. The method for machining and assembling the inner bottom milling groove of the liquid rocket engine based on the inner bottom milling groove positioning clamp of the liquid rocket engine as claimed in claim 1 is characterized by comprising the following steps: Step one, positioning a carcass (2) in the center of a machine tool workbench in a mode that a positioning shaft (3) is matched with the machine tool workbench through a shaft hole during milling a workpiece, and locking and positioning the carcass (2) and the machine tool workbench through a compression bolt (5) and a nut (4); step two, loading a workpiece into the tire body (2), wherein the bottom of an inner hole of the workpiece is contacted with the top surface of the outer shape of the tire body (2), the workpiece and the tire body (2) are positioned in the circumferential direction through a positioning pin (7) and a positioning cover plate (1), the workpiece is prevented from rotating in the circumferential direction, a locking bolt (6) penetrates through the workpiece to be connected with the tire body (2) in a threaded manner, and the workpiece is tightly attached to the tire body (2) by axial locking force, so that the workpiece is prevented from moving along the axial direction; step three, after the processing of the workpiece is completed, taking out the long locating pin (7), connecting the locating cover plate (1) with the workpiece through shaft hole matching by the short locating pin (10), loosening the locking bolt (6) to ensure that the workpiece and the locating cover plate (1) can rotate together relative to the carcass, and rotating the workpiece to enable the locking threaded hole of the locating cover plate (1) to coincide with the threaded hole of the lifting block (8); and fourthly, connecting the positioning cover plate and the workpiece with an internal threaded hole of the lifting block (8) through a connecting bolt (9), fixing the lifting ring (11) and the positioning cover plate (1) through threaded connection, pulling the lifting ring (11) up by using a crane to generate pulling force, and enabling the workpiece to generate reverse motion vertical to a machine tool workbench so as to separate a product from a carcass.

Description

Positioning fixture for milling grooves in inner bottom of liquid rocket engine and machining and assembling method of positioning fixture Technical Field The invention belongs to the technical field of machining, and relates to a positioning fixture for milling grooves in an inner bottom of a liquid rocket engine and a machining assembly method thereof. Background The injector of the liquid rocket engine is an especially important part in an engine thrust chamber, is a part where a fuel agent and an oxidant are fully atomized and mixed, and the quality of the injector directly influences the combustion thrust performance of the rocket engine to determine the success or failure of ignition emission. The inner bottom and the injector shell are main components in the injector, wherein the inner bottom and the injector shell are mutually assembled to form mutually independent sealing cavities for isolating fuel and oxidant, so that the requirement on the size precision and cylindricity of the inner bottom is high, the fit clearance between the inner bottom and the injector shell is strict, the injector working environment is high temperature and high pressure, hundreds of spiral grooves are uniformly distributed on the inner bottom outer surface to meet the working condition requirement, the spiral grooves are used as fuel circulation channels in the working environment, the circulating cooling effect on the injector is achieved, the channel circulation length is increased in a spiral groove mode to achieve better cooling effect, the stress and cooling uniformity in the working process are guaranteed, the copper alloy material is used for guaranteeing the size consistency of the spiral grooves, the copper alloy material has better heat conducting effect, but the material is soft and easy to deform, and a special tool is designed to control deformation in the processing process of the copper alloy inner bottom spiral grooves, and the size consistency of the spiral grooves is guaranteed. Disclosure of Invention The invention solves the technical problems of overcoming the defects of the traditional processing method that a copper alloy inner bottom workpiece is easy to deform, difficult to mount and clamp and difficult to detach when milling a spiral groove, providing an integral processing technical device for milling the spiral groove on the inner bottom of an engine injector, which is convenient to detach, stable to process and low in cost, is specially used for processing spiral groove milling procedures on a processing center machine tool on the inner bottom of a liquid rocket engine injector with a specific model, can realize accurate positioning and convenient detachment of workpiece processing, can realize mass product processing in products, and effectively ensures product quality and production progress. The technical scheme of the invention is that the positioning fixture for milling grooves in the inner bottom of the liquid rocket engine comprises a groove milling tool, wherein the groove milling tool comprises a positioning cover plate, a carcass, a positioning shaft, a nut, a compression bolt, a locking bolt and a long positioning pin; The positioning shaft is used for positioning the tire body on the machine tool workbench through shaft hole matching, the tire body is locked and fixed with the machine tool workbench through a compression bolt, the outer profile of the tire body is matched with the inner profile of the workpiece, the workpiece is sleeved on the upper end of the tire body, the positioning cover plate is pressed above the workpiece, positioning holes are formed in the corresponding positions of the positioning cover plate, the tire body and the workpiece, long positioning pins are inserted into the positioning holes from top to bottom and used for positioning the relative positions of the workpiece, the tire body and the positioning cover plate, so that the workpiece is prevented from rotating circumferentially, locking holes are formed in the corresponding positions of the positioning cover plate, the tire body and the workpiece, the locking bolt is inserted into the locking threaded holes from top to bottom, the positioning cover plate, the workpiece and the tire body are sequentially penetrated through to be screwed and locked, and the workpiece is tightly attached to the tire body by generating axial locking force, and the axial movement of the workpiece is prevented. Preferably, a gap of 0.05 mm-0.1 mm is reserved between the carcass and the workpiece to be processed. Preferably, the carcass outer circumference runout is not more than 0.02mm. Preferably, the carcass top surface outer circumferential flatness is no more than 0.05mm. Preferably, the bottom of the tire body is of a disc structure, a plurality of open slots are formed in the side face of the disc, and the tire body can be locked and fixed with machine tool tables of different models through the open slots in differe