A liquid rocket engine inner bottom milling groove positioning clamp and a processing and assembling method thereof

Abstract

The application provides a liquid rocket engine inner bottom milling groove positioning clamp and a processing and assembling method thereof, and belongs to the technical field of machining. When a workpiece is milled, a tire body is locked and positioned on a machine tool workbench; the workpiece is loaded into the tire body, the inner hole bottom of the workpiece is in contact with the top surface of the tire body, the workpiece and the tire body are circumferentially positioned through positioning pins and a positioning cover plate, a locking bolt is screwed through the workpiece and the tire body, and the axial locking force tightly attaches the workpiece to the tire body; after the clamping is finished, the workpiece is milled. After the workpiece is processed, the long positioning pin is taken out, the short positioning pin is matched through the shaft hole to connect the positioning cover plate and the workpiece, the locking bolt is loosened and taken out, the workpiece is rotated to make the positioning cover plate locking thread hole coincide with the thread hole of the hoisting block, the hoisting ring is pulled up, the workpiece generates reverse movement perpendicular to the machine tool workbench, and the product is separated from the tire body. The application is accurate and reliable in positioning, complete in function, convenient to operate, small in weight and safe and reliable.

Description

Technical Field

[0001] This invention belongs to the field of machining technology and relates to a positioning fixture for milling grooves on the inner bottom of a liquid rocket engine and its machining and assembly method. Background Technology

[0002] The injector of a liquid rocket engine is a particularly important component in the engine thrust chamber. It is the part where the fuel and oxidizer are fully atomized and mixed. The quality of the injector directly affects the combustion thrust performance of the rocket engine and determines the success or failure of ignition and launch. The inner bottom and the injector housing are the main components of the injector. The outer shape of the inner bottom and the inner shape of the injector housing must be assembled to form independent sealed cavities to isolate the fuel and oxidizer. Therefore, the dimensional accuracy and cylindricity of the inner bottom outer shape are required, and the fit clearance between it and the injector housing must be strictly controlled. The injector operates in a high-temperature and high-pressure environment. To meet the requirements of the working conditions, hundreds of spiral grooves are evenly distributed on the outer surface of the inner bottom. These spiral grooves serve as fuel flow channels in the working environment, playing a role in circulating cooling of the injector. The spiral grooves increase the flow length of the channels to achieve better cooling effect. To ensure the uniformity of stress and cooling during operation, the dimensional consistency of the spiral grooves is required. The inner bottom is made of copper alloy material. Copper alloy has better thermal conductivity, but the material is soft and easily deformed. Therefore, a set of special tooling should be designed to control the deformation of the spiral grooves in the copper alloy inner bottom during the machining process and ensure the dimensional consistency of the spiral grooves. Summary of the Invention

[0003] The technical problem solved by this invention is to overcome the shortcomings of traditional machining methods that are prone to deformation, difficult to clamp, and difficult to disassemble when milling spiral grooves on the inner bottom of copper alloy workpieces. It provides an integrated, easy-to-disassemble, stable, and low-cost machining process equipment for milling spiral grooves on the inner bottom of engine injectors. This equipment is specifically designed for machining the spiral groove process on the inner bottom of a specific type of liquid rocket engine injector on a machining center machine tool. It enables precise workpiece positioning and easy disassembly, allowing for mass production and effectively ensuring product quality and production schedule.

[0004] The technical solution of the present invention is: a positioning fixture for milling grooves on the inner bottom of a liquid rocket engine, the positioning fixture including a milling tool, the milling tool including a positioning cover plate, a jig, a positioning shaft, a nut, a clamping bolt, a locking bolt, and a long positioning pin;

[0005] The positioning shaft is located at the lower end of the jig body and is coaxially connected to it. The positioning shaft is used to position the jig body on the machine tool table through a shaft hole. The jig body and the machine tool table are locked together by clamping bolts and nuts. The outer surface of the jig body matches the inner surface of the workpiece. The workpiece is fitted onto the upper end of the jig body, and the positioning cover plate presses down on top of the workpiece. Positioning holes are provided at corresponding positions on the positioning cover plate, jig body, and workpiece. Long positioning pins are inserted from top to bottom into the positioning holes to position the relative positions of the workpiece, jig body, and positioning cover plate, preventing circumferential rotation of the workpiece. Locking holes are provided at corresponding positions on the positioning cover plate, jig body, and workpiece. Locking bolts are inserted from top to bottom into the locking threaded holes, sequentially passing through the positioning cover plate, workpiece, and jig body to form a threaded locking connection, generating axial locking force to tightly hold the workpiece against the jig body, preventing axial movement of the workpiece.

[0006] Preferably, there is a gap of 0.05mm to 0.1mm between the jig and the workpiece to be processed.

[0007] Preferably, the runout of the outer circle of the tire is no more than 0.02 mm.

[0008] Preferably, the flatness of the outer circumference of the top surface of the tire body is no greater than 0.05 mm.

[0009] Preferably, the bottom of the tire body is a disc structure, and the side of the disc is provided with multiple opening slots. The tire body can be locked and fixed to the worktable of different models of machine tools through the opening slots at different positions by clamping bolts and nuts.

[0010] Preferably, the above-mentioned liquid rocket engine inner bottom milling groove positioning fixture further includes a lifting fixture, which includes a lifting block, connecting bolts, short positioning pins, and a lifting ring;

[0011] The lifting block is placed in the lifting rectangular groove on the top of the tire body, and the center of the lifting block is provided with a threaded hole structure;

[0012] The connecting bolts are used to connect the locking threaded holes of the positioning cover plate to the internal threaded holes of the lifting block;

[0013] The short locating pin is used to connect the locating cover plate to the workpiece through the shaft hole, so that the workpiece and the locating cover plate can rotate together relative to the jig body;

[0014] The lower end of the lifting ring is provided with external threads, and the top center of the positioning cover plate is provided with a lifting thread hole;

[0015] The lifting ring is matched and fixed with the lifting threaded hole of the positioning cover plate.

[0016] Preferably, there are four locking threaded holes, which are evenly distributed on the top surface of the tire body on the same circumference.

[0017] Preferably, there are four rectangular hoisting slots, which are evenly distributed on the same circumference at 45° intervals from the locking threaded holes.

[0018] Preferably, the tire body has two positioning holes, which are distributed on a concentric circle with the locking threaded hole and are symmetrically distributed with respect to the center of the circle.

[0019] A method for machining and assembling milled grooves on the inner bottom of a liquid rocket engine based on the above-mentioned device, characterized in that:

[0020] Step 1: When milling grooves on the workpiece, the positioning shaft and the machine tool table are fitted together to position the jig body at the center of the machine tool table. The jig body and the machine tool table are locked and positioned by clamping bolts and nuts.

[0021] Step 2: Load the workpiece into the jig body. The bottom of the inner hole of the workpiece contacts the top surface of the jig body. The workpiece and the jig body are circumferentially positioned by the positioning pin and the positioning cover plate to prevent the workpiece from rotating circumferentially. The locking bolt is threaded through the workpiece and the jig body. The axial locking force keeps the workpiece tightly against the jig body to prevent the workpiece from moving axially.

[0022] Step 3: After the workpiece is processed, remove the long locating pin and then connect the short locating pin to the locating cover plate and the workpiece through the shaft hole. Loosen the locking bolts to ensure that the workpiece and the locating cover plate can rotate together relative to the jig body. Rotate the workpiece so that the locking thread hole of the locating cover plate coincides with the thread hole of the lifting block.

[0023] Step 4: Connect the positioning cover plate and the workpiece to the internal threaded hole of the lifting block by connecting bolts. Fix the lifting ring (to the positioning cover plate by threaded connection) and use the crane to generate pulling force to lift the lifting ring. The workpiece will move in the opposite direction perpendicular to the machine tool table, causing the product to separate from the jig.

[0024] The advantages of this invention compared to the prior art are:

[0025] (1) The workpiece to be milled and the milling fixture designed in this invention have a high degree of fit and small gap, resulting in high workpiece positioning accuracy and effectively preventing deformation during product mounting.

[0026] (2) The milling fixture designed in this invention has a positioning shaft structure at the lower end of the fixture body, which facilitates the quick positioning, clamping and alignment of the milling fixture on the machine tool workbench.

[0027] (3) The present invention has a reasonable design for the tire removal fixture structure. Four lifting rectangular slots are designed on the tire body of the milling fixture. Lifting blocks of the same size are placed in the rectangular slots. The center of the rectangular blocks has a threaded hole. When disassembling the workpiece, the lifting blocks can be used to quickly disassemble the workpiece.

[0028] (4) The liquid rocket engine inner bottom milling groove positioning fixture described in this invention can be used for pressing, milling and unloading tires on the inner bottom of the engine.

[0029] Instruction manual illustrations

[0030] Figure 1 This is a three-dimensional view of the milling fixture according to an embodiment of the present invention;

[0031] Figure 2 This is a sectional view of the milling tooling according to an embodiment of the invention;

[0032] Figure 3 A three-dimensional view of the tire unloading tool according to an embodiment of the invention;

[0033] Figure 4 This is a cross-sectional view of the tire unloading tool according to an embodiment of the invention;

[0034] Figure 5 This is a schematic diagram of the tire body structure according to an embodiment of the invention;

[0035] Figure 6 This is a schematic diagram of the positioning cover plate structure according to an embodiment of the invention;

[0036] Figure 7 This is a schematic diagram of the lifting ring structure in an embodiment of the invention;

[0037] Figure 8 This is a schematic diagram of the quick-lifting structure according to an embodiment of the invention;

[0038] Figure 9 This is a schematic diagram of the long locating pin structure in an embodiment of the invention;

[0039] Figure 10 This is a schematic diagram of the short locating pin structure in an embodiment of the invention. Detailed Implementation

[0040] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0041] This invention provides a positioning fixture for milling grooves on the inner bottom of a liquid rocket engine, which consists of a milling tool and a tire removal tool.

[0042] like Figure 1 , Figure 2As shown, the milling fixture includes a positioning cover plate 1, a fixture body 2, a positioning shaft 3, a nut 4, a clamping bolt 5, a locking bolt 6, and a long positioning pin 7. The positioning shaft 3 is located at the lower end of the fixture body 2 and is coaxially connected to the fixture body 2. The positioning shaft 3 is used to position the fixture body 2 on the machine tool worktable through a shaft hole fit, facilitating precise positioning of the milling fixture and the worktable. The fixture body 2 and the machine tool worktable are locked and fixed by the clamping bolt 5 and the nut 4. The outer surface of the fixture body 2 matches the inner surface of the workpiece. The workpiece is fitted onto the upper end of the fixture body 2. The positioning cover plate 1... The positioning cover plate 1, the base plate 2, and the workpiece are provided with positioning holes at corresponding positions. The long positioning pin 7 is inserted into the positioning hole from top to bottom to position the relative position of the workpiece 21 with the base plate 2 and the positioning cover plate 1, preventing the workpiece from rotating circumferentially. The positioning cover plate 1, the base plate 2, and the workpiece are provided with locking holes at corresponding positions. The locking bolt 6 is inserted into the locking thread hole from top to bottom, and passes through the positioning cover plate 1, the workpiece, and the base plate 2 in sequence to form a threaded locking connection, generating an axial locking force to keep the workpiece tightly attached to the base plate 2, preventing the workpiece from moving axially.

[0043] In a specific embodiment of the present invention, there is a gap of 0.05mm to 0.1mm between the jig body 2 and the workpiece to be processed; the runout of the outer circle of the jig body 2 is no greater than 0.02mm; and the flatness of the outer circle of the top surface of the jig body 2 is no greater than 0.05mm.

[0044] The bottom of the tire body 2 is a disc structure, and the side of the disc is provided with multiple opening slots. The tire body 2 can be locked and fixed to the machine tool worktable 22 of different models through the opening slots at different positions by clamping bolts 5 and nuts 4.

[0045] like Figure 3 , Figure 4 As shown, the tire unloading tool includes: lifting block 8, connecting bolt 9, short positioning pin 10, and lifting ring 11.

[0046] The lifting fixture includes a lifting block 8, connecting bolts 9, short positioning pins 10, and a lifting ring 11;

[0047] The lifting block 8 is placed in the lifting rectangular groove on the top of the tire body 2, and the center of the lifting block 8 is provided with a threaded hole structure;

[0048] The connecting bolt 9 is used to pass through the locking threaded hole of the positioning cover plate 1 and connect with the internal threaded hole of the lifting block 8;

[0049] like Figure 10 As shown, the short locating pin 10 is used to connect the locating cover plate 1 to the workpiece through the shaft hole, so that the workpiece and the locating cover plate 1 can rotate together relative to the jig body.

[0050] The lower end of the lifting ring 11 is provided with external threads, and the top center of the positioning cover plate 1 is provided with a lifting thread hole;

[0051] The lifting ring 11 is matched and fixed with the lifting threaded hole of the positioning cover plate 1.

[0052] like Figure 5 As shown, in a specific embodiment of the present invention, there are four lifting rectangular slots, evenly distributed at 45° intervals on the same circumference as the locking threaded holes. The dimensions of the lifting rectangular slots are length * width * height = 50 * 30 * 25. Correspondingly, the structure of the lifting block 8 is a cuboid with length * width * height = 50 * 30 * 24, and the center of the cuboid is a threaded hole structure for connecting the lifting ring, such as... Figure 7 , Figure 8 As shown.

[0053] like Figure 6 As shown, in a specific embodiment of the present invention, the outer diameter of the positioning cover plate 1 is equal to the diameter of the machined part, and four locking holes are evenly distributed circumferentially in a direction equal to the circumferential diameter of the locking holes of the tire body 2. The tire body 2 has two positioning holes, distributed on a concentric circle with the locking threaded holes, and symmetrically distributed with respect to the center of the circle. Figure 9 As shown, the long locating pin and the short locating pin are cylindrical structures.

[0054] When disassembling the processed workpiece, the jig body 2 is fixed to the machine tool worktable by clamping bolt 5. The long positioning pin 7 is removed and the short positioning pin 10 is connected to the positioning cover plate 1 and the workpiece through the shaft hole. The locking bolt 6 is loosened to ensure that the workpiece and the positioning cover plate 1 rotate together relative to the jig body. The workpiece is rotated so that the locking thread hole of the positioning cover plate 1 coincides with the thread hole of the lifting block 8. The workpiece is connected to the internal thread hole of the lifting block by connecting bolt 9. The crane and the lifting ring 11 generate a reverse movement perpendicular to the worktable to separate the product from the jig body.

[0055] In a specific embodiment of the present invention, four positioning blocks 8 are placed in the rectangular positioning groove of the tire body 1 for fixation. After the product is processed, the positioning blocks 8 can be used to disassemble the product.

[0056] The principle behind the above scheme is:

[0057] Before milling the product groove, the positioning shaft 3 is used to position the jig 2 at the center of the machine tool table through the shaft hole fit. The jig 2 and the machine tool table are locked and positioned by clamping bolts 5 and nuts 4. When milling the product groove, the workpiece is loaded into the jig 2, ensuring that the bottom of the inner hole of the workpiece is in contact with the top surface of the outer shape of the jig 2. The workpiece and the jig 2 are circumferentially positioned by positioning pins 7 and positioning cover plates 1 to prevent the workpiece from rotating circumferentially. The locking bolts 6 are threaded through the workpiece and the jig 2, and the axial locking force keeps the workpiece tightly against the jig 2 to prevent the workpiece from moving axially. After the workpiece is processed, remove the long positioning pin 7 and then connect the short positioning pin 10 to the positioning cover plate 1 and the workpiece through the shaft hole. Loosen the locking bolt 6 to ensure that the workpiece and the positioning cover plate 1 can rotate together relative to the jig. Rotate the workpiece so that the locking thread hole of the positioning cover plate 1 coincides with the thread hole of the lifting block 8. Connect the lifting ring 11 to the internal thread hole of the lifting block 8 through the connecting bolt 9. Fix the lifting ring 11 to the positioning cover plate 1 through the threaded connection. Use the crane to generate the pulling force to lift the lifting ring 11. The workpiece will move in the opposite direction perpendicular to the worktable, so that the product will separate from the jig. The processed product will be disassembled.

[0058] Based on the above-mentioned apparatus, the present invention provides a method for machining and assembling milled grooves on the inner bottom of a liquid rocket engine, the method comprising the following steps:

[0059] Step 1: When milling grooves on the workpiece, the positioning shaft 3 and the machine tool table are fitted with shaft holes to position the jig body 2 at the center of the machine tool table. The jig body 2 and the machine tool table are locked and positioned by clamping bolts 5 and nuts 4.

[0060] Step 2: Place the workpiece into the fixture 2, ensuring the bottom of the workpiece's inner hole contacts the top surface of the fixture 2. The workpiece and fixture 2 are circumferentially positioned using the locating pin 7 and locating cover plate 1 to prevent circumferential rotation of the workpiece. Thread the locking bolt 6 through the workpiece and fixture 2, using axial locking force to firmly hold the workpiece against the fixture 2, preventing axial movement. In this step, a torque wrench is used to tighten the locking bolt, quantifying the tightening torque to avoid instability in clamping and positioning due to inconsistent tightening forces. After clamping, perform milling on the workpiece.

[0061] Step 3: After the workpiece is processed, remove the long positioning pin 7 and then connect the short positioning pin 10 to the positioning cover plate 1 and the workpiece through the shaft hole. Loosen the locking bolt 6 to ensure that the workpiece and the positioning cover plate 1 can rotate together relative to the jig body. Rotate the workpiece so that the locking thread hole of the positioning cover plate 1 coincides with the thread hole of the lifting block 8.

[0062] Step 4: Connect the lifting ring 11 to the positioning cover plate 1 by passing the connecting bolt 9 through the internal threaded hole of the workpiece and the lifting block 8. Fix the workpiece between the positioning cover plate and the positioning block by axial locking force. Use the crane to generate pulling force to lift the lifting ring 11, and the workpiece will move in the opposite direction perpendicular to the machine tool table, so that the product will separate from the jig.

[0063] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A positioning fixture for milling grooves on the inner bottom of a liquid rocket engine, characterized in that... The milling fixture includes a positioning cover plate (1), a jig body (2), a positioning shaft (3), a nut (4), a clamping bolt (5), a locking bolt (6), a long positioning pin (7), and a lifting fixture. The positioning shaft (3) is located at the lower end of the body (2) and is coaxially connected to the body (2). The positioning shaft (3) is used to position the body (2) on the machine tool table through the shaft hole. The body (2) and the machine tool table are locked and fixed by the clamping bolt (5) and the nut (4). The outer surface of the body (2) matches the inner surface of the workpiece. The workpiece is fitted on the upper end of the body (2), and the positioning cover plate (1) is pressed on the workpiece. The positioning cover plate (1), the body (2) and the workpiece are provided with positioning at corresponding positions. A long positioning pin (7) is inserted from top to bottom into the positioning hole to position the relative position of the workpiece with the body (2) and the positioning cover plate (1) to prevent the workpiece from rotating circumferentially; the positioning cover plate (1), the body (2) and the workpiece are provided with locking holes at corresponding positions, and the locking bolt (6) is inserted from top to bottom into the locking thread hole, passing through the positioning cover plate (1), the workpiece and the body (2) in sequence to lock the connection with the thread, generating an axial locking force to keep the workpiece tightly attached to the body (2) to prevent the workpiece from moving axially; The hoisting fixtures include hoisting blocks (8), connecting bolts (9), short positioning pins (10), and hoisting rings (11). The lifting block (8) is placed in the lifting rectangular groove on the top of the tire body (2), and the center of the lifting block (8) is provided with a threaded hole structure; The connecting bolt (9) is used to connect the locking thread hole of the positioning cover plate (1) to the internal thread hole of the lifting block (8); The short locating pin (10) is used to connect the locating cover plate (1) to the workpiece through the shaft hole, so that the workpiece and the locating cover plate (1) can rotate together relative to the body. The lower end of the lifting ring (11) is provided with an external thread, and the top center of the positioning cover plate (1) is provided with a lifting thread hole; The lifting ring (11) is matched and fixed with the lifting threaded hole of the positioning cover plate (1).

2. The positioning fixture for the inner bottom milling groove of a liquid rocket engine according to claim 1, characterized in that... There is a gap of 0.05mm to 0.1mm between the body (2) and the workpiece to be processed.

3. A positioning fixture for milling grooves on the inner bottom of a liquid rocket engine according to claim 1, characterized in that... The outer circle runout of the tire body (2) is no more than 0.02 mm.

4. A positioning fixture for milling grooves on the inner bottom of a liquid rocket engine according to claim 1, characterized in that... The flatness of the outer circle of the top surface of the tire body (2) is not greater than 0.05 mm.

5. A positioning fixture for milling grooves on the inner bottom of a liquid rocket engine according to claim 1, characterized in that... The bottom of the tire body (2) is a disc structure, and the side of the disc is provided with multiple opening slots. The tire body (2) can be locked and fixed to the worktable of different models of machine tools through the opening slots at different positions by clamping bolts (5) and nuts (4).

6. A positioning fixture for milling grooves on the inner bottom of a liquid rocket engine according to claim 1, characterized in that: There are four locking threaded holes, which are evenly distributed on the top surface of the tire body (2) on the same circumference.

7. A positioning fixture for milling grooves on the inner bottom of a liquid rocket engine according to claim 1, characterized in that... There are four rectangular hoisting slots, which are evenly distributed on the same circumference at 45° intervals from the locking threaded holes.

8. A positioning fixture for milling grooves on the inner bottom of a liquid rocket engine according to claim 1, characterized in that... There are two positioning holes on the tire body (2), which are distributed on the same concentric circle as the locking thread hole and are symmetrically distributed with respect to the center of the circle.

9. A method for machining and assembling the inner bottom milling groove of a liquid rocket engine based on the positioning fixture for the inner bottom milling groove of a liquid rocket engine according to claim 1, characterized in that: Step 1: When milling the workpiece, the positioning shaft (3) and the machine tool table are connected by the shaft hole to position the jig (2) at the center of the machine tool table. The jig (2) and the machine tool table are locked and positioned by clamping bolts (5) and nuts (4). Step 2: Insert the workpiece into the body (2). The bottom of the inner hole of the workpiece contacts the top surface of the outer shape of the body (2). The workpiece and the body (2) are circumferentially positioned by the positioning pin (7) and the positioning cover plate (1) to prevent the workpiece from rotating circumferentially. The locking bolt (6) is threaded through the workpiece and the body (2). The axial locking force keeps the workpiece tightly attached to the body (2) to prevent the workpiece from moving along the axial direction. Step 3: After the workpiece is processed, take out the long positioning pin (7) and then connect the positioning cover plate (1) to the workpiece through the shaft hole by using the short positioning pin (10). Loosen the locking bolt (6) to ensure that the workpiece and the positioning cover plate (1) can rotate together relative to the jig body. Rotate the workpiece so that the locking thread hole of the positioning cover plate (1) coincides with the thread hole of the lifting block (8). Step 4: Connect the positioning cover plate and the workpiece to the internal threaded hole of the lifting block (8) by connecting bolt (9), fix the lifting ring (11) and the positioning cover plate (1) by threaded connection, use the crane to generate pulling force to lift the lifting ring (11), the workpiece generates a reverse movement perpendicular to the machine tool table, so that the product separates from the body.

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