A general fixture for turbine pump casing machining

Abstract

The utility model relates to aerospace precision machining equipment technical field, especially a kind of general fixture for turbine pump shell machining, including base, precision chuck, base plate, three groups of moving slider, three centering clamping jaws and three pressing plate;Adopt composite positioning mode, through high-precision chuck three-jaw self-centering principle, initial positioning X, Y centering;Adopt three-point plane principle, utilize the locating surface of spherical contact component, realize Z positioning;Base plate adopts thread+positioning pin hole combination;It can be quickly disassembled according to different product size conversion positioning and clamping.This utility model clamps shell class parts, adopts three-jaw self-centering clamping mode to cooperate three-point spherical positioning principle.And adopt the end face of axial compression part, can be well guaranteed part deformation, realize shell processing process clamping without deformation, ensure turbine pump shell machining after ultrahigh precision, clamping operation is convenient, improve processing efficiency, satisfy design requirement after processing.

Description

Technical Field

[0001] This utility model relates to the field of aerospace precision machining equipment technology, and in particular to a general-purpose fixture for machining turbine pump housings. Background Technology

[0002] The turbopump is a core component of a rocket engine, and its performance directly affects the engine's thrust and reliability. Traditional machining processes struggle to meet the precision requirements under high-speed (≥20,000 rpm) and high-pressure (≥50 MPa) conditions, leading to efficiency losses and safety hazards. Traditional machining tooling suffers from the following shortcomings: Lack of self-adaptability: The flatness and dimensions of flange end faces vary between different shells, and traditional tooling cannot quickly adjust the positioning reference. Positioning defects: When using ordinary clamping plates, factors such as the shell blank, rough machining, and heat treatment can cause unevenness on the end faces of the parts, leading to deformation during clamping. The resulting dimensions and geometric tolerances cannot meet design requirements (typically ≥0.05 mm), affecting product quality and assembly requirements. Clamping force defects: Using ordinary three-jaw chucks, insufficient clamping force makes safe production impossible, while excessive clamping force causes part deformation after machining, with roundness ≥0.05 mm, severely impacting the consistency of subsequent machining references and becoming a precision bottleneck.

[0003] Traditional clamping methods in production and processing include chucks, pressure plates, and mandrel expansion sleeves. Chucks have a large clamping force, which can cause parts to deform. If the clamping force is too small, it cannot meet the requirements for safe production. Pressure plates are subject to deformation due to heat treatment or blanks. Mandrel expansion sleeves are usually suitable for small-diameter parts. For large-diameter products, the cost is extremely high. The prerequisite for using mandrel expansion sleeves is that the clamping and positioning parts must meet the roundness requirements in order to ensure that the processed parts are qualified. Utility Model Content

[0004] To solve the above-mentioned technical problems, this utility model discloses a universal fixture for machining turbine pump housings.

[0005] The specific technical solution is as follows: A general-purpose fixture for machining turbine pump housings includes a base, a precision chuck, a base plate, three sets of movable sliders, three centering jaws, and three pressure plates. The base has six countersunk holes A evenly spaced along its circumference. The precision chuck has three sets of slides spaced at 120° intervals and six countersunk holes B evenly spaced along its circumference. The base plate has three sets of clearance slots and three rows of locating pin holes spaced at 120° intervals, and six countersunk holes C evenly spaced along its circumference. Each set of movable sliders has two locating grooves A extending downwards along its width on its upper surface, and its upper surface is machined along its length... The positioning boss A has a sliding groove on each of its two sides along the length direction, and four threaded holes B are formed on the upper surface of the movable slider; the top surface of each centering claw has steps one, two, and three from high to low, with countersunk holes D and E respectively on steps one and three; the bottom surface of the centering claw is machined into a positioning boss B along the width direction, and a positioning groove B is machined along the length direction; both end faces of the centering claw have arcs, and the centering claw can be rotated 180° for installation, and can be internally supported or externally clamped; each pressure plate has a set of waist-shaped through grooves and a threaded through hole along the length direction.

[0006] Each row of positioning pin holes contains nine holes, all with internal threads, for installing pressure plates and ball-head positioning pins.

[0007] The slide rail is machined with teeth, and the bottom surface of the movable slider is machined with matching teeth.

[0008] The two ends of steps one, two, and three are all machined into a tooth shape.

[0009] The front end of the pressure plate is machined into a shrink head, which abuts against the shell.

[0010] When the pressure plate presses the housing, bolt C is screwed into the waist-shaped through groove and the positioning pin hole to lock it in place, and bolt D is screwed into the positioning pin hole in reverse to adjust the height.

[0011] The movable slider and centering jaw are connected by screwing bolt B into countersunk hole D and threaded hole B, and countersunk hole E and threaded hole B.

[0012] The positioning boss A matches the positioning groove B; the positioning boss B matches the positioning groove A.

[0013] The slide rail is machined into a groove along the radial direction inside, which matches the sliding groove of the moving slider.

[0014] The base and precision chuck are installed by screwing bolt A into countersunk holes A and B respectively.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: This invention relates to an ultra-precision machining fixture for rocket engine turbopump housings, particularly addressing the high-precision machining requirements of a post-machining cylindricity of ≤0.005mm. For housing-type parts, it effectively controls machining deformation, improving part machining quality and efficiency. Controllable machining accuracy effectively ensures consistency with subsequent machining datums, resolving precision limitations and guaranteeing the precision requirements of turbopumps under high-speed (≥20,000rpm) and high-pressure (≥50MPa) conditions. The machined parts exhibit no deformation, improving the first-pass yield.

[0016] This utility model employs a three-jaw self-centering clamping method combined with a three-point spherical positioning principle when clamping shell-type parts. It also uses axial clamping of the part's end face, effectively preventing part deformation and achieving deformation-free clamping during shell machining. This ensures ultra-high precision after machining of the turbine pump shell, facilitates clamping operations, improves machining efficiency, and guarantees that the machined part meets design requirements. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural diagram of the clamp of this utility model; Figure 2 This is a three-dimensional structural diagram of the base of this utility model; Figure 3 This is a three-dimensional structural diagram of the precision chuck of this utility model; Figure 4 This is a three-dimensional structural diagram of the base plate of this utility model; Figure 5 for Figure 4 Cross-sectional view of the base plate; Figure 6 This is a three-dimensional structural diagram of the centering claw of this utility model; Figure 7 This is a three-dimensional structural diagram of the ball-head positioning pin of this utility model; Figure 8 This is a three-dimensional structural diagram of the combination of the centering claw and the movable slider of this utility model; Figure 9 for Figure 8 Cross-sectional view of the centering jaw and moving slider assembly; Figure 10 This is a three-dimensional structural diagram of the movable slider of this utility model; Figure 11 This is a three-dimensional structural diagram of the pressure plate of this utility model; In the diagram: 1. Base; 101. Countersunk hole A; 2. Precision chuck; 21. Countersunk hole B; 22. Slide rail; 3. Base plate; 31. Countersunk hole C; 32. Locating pin hole; 33. Threaded hole A; 34. Clearance groove; 4. Moving slider; 41. Sliding groove; 42. Locating groove A; 43. Locating boss A; 44. Threaded hole B; 5. Centering claw; 51. Step 1; 52. Step 2; 53. Step 3; 54. Countersunk hole D; 55. Countersunk hole E; 56. Locating boss B; 57. Locating groove B; 6. Pressure plate; 61. Waist-shaped through groove; 62. Threaded through hole; 7. Ball head locating pin; 8. Bolt A; 9. Bolt B; 10. Bolt C; 11. Bolt D. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the accompanying drawings.

[0019] Figure 1 This is a three-dimensional structural diagram of the clamp of this utility model. Figure 2 This is a three-dimensional structural diagram of the base of this utility model. Figure 3 This is a three-dimensional structural diagram of the precision chuck of this utility model. Figure 4 This is a three-dimensional structural diagram of the base plate of this utility model. Figure 5 for Figure 4 Cross-sectional view of the base plate. Figure 6 This is a three-dimensional structural diagram of the centering claw of this utility model. Figure 7 This is a three-dimensional structural diagram of the ball-head positioning pin of this utility model. Figure 8 This is a three-dimensional structural diagram of the combination of the centering claw and the movable slider of this utility model. Figure 9 for Figure 8 Cross-sectional view of the centering jaw and moving slider assembly. Figure 10 This is a three-dimensional structural diagram of the movable slider of this utility model. Figure 11 The figure shows a three-dimensional structural diagram of the pressure plate of this utility model: This utility model is a general-purpose fixture for machining turbine pump housings, including a base 1, a precision chuck 2, a base plate 3, three sets of movable sliders 4, three centering jaws 5, and three pressure plates 6; the base 1 has six countersunk holes A101 evenly opened along the circumferential direction; the precision chuck 2 has three sets of slides 22 at 120° intervals, the slides 22 are machined into teeth, the bottom surface of the movable sliders 4 is machined into matching teeth, and the interior of the slides 22 is machined into a groove along the radial direction to match the sliding groove 41 of the movable sliders 4. The precision chuck 2 has six countersunk holes B21 evenly spaced along its circumference. The base 1 and the precision chuck 2 are installed by screwing bolts A8 into the countersunk holes A101 and B21 respectively. The base plate 3 has three sets of clearance grooves 34 spaced apart and at 120° intervals and three rows of positioning pin holes 32. Each row of positioning pin holes 32 contains nine holes, all with internal threads, for installing the pressure plate and ball-head positioning pins 7. The ball-head positioning pins 7 ensure three-point contact of the bottom surface of the part, ensuring no deformation during clamping. The base plate 3 has six countersunk holes C31 evenly spaced along the circumference; the upper surface of each set of movable sliders 4 has two positioning grooves A42 downward along the width direction, and the upper surface is machined into a positioning boss A43 along the length direction. A sliding groove 41 is opened on each of the two sides along the length direction. A total of four threaded holes B44 are opened on the upper surface of the movable slider 4; the top surface of each centering claw 5 has, from high to low, steps 51, 52, and 53. The two ends of steps 51, 52, and 53 are all machined into teeth. Steps 51 and 53... Countersunk holes D54 and E55 are respectively opened on the three 53. The bottom surface of the centering claw 5 is machined into a positioning boss B56 along the width direction. The positioning boss A43 matches the positioning groove B57; the positioning boss B56 matches the positioning groove A42. A positioning groove B57 is machined along the length direction of the centering claw 5. Both end faces of the centering claw have arcs. The centering claw can be rotated 180° for installation and can be internally supported or externally clamped. The movable slider 4 and the centering claw 5 are connected by screwing the bolt B9 into the countersunk hole D54 and the threaded hole B44, and the countersunk hole E55 and the threaded hole B44.

[0020] Each pressure plate 6 has a set of waist-shaped through grooves 61 and a threaded through hole 62 along its length. The front end of the pressure plate 6 is machined into a shrink head to abut against the shell. When the pressure plate 6 presses against the shell, the bolt C10 is screwed into the waist-shaped through groove 61 and the positioning pin hole 32 to lock it in place, and the bolt D11 is screwed into the positioning pin hole 32 inverted to adjust the height.

[0021] The base is made of CrWMn tool steel, with overall quenching treatment and grinding at both ends to ensure parallelism of 0.02mm and flatness of 0.01mm. The base plate is also made of CrWMn tool steel, with overall quenching treatment and grinding at both ends to ensure parallelism of 0.02mm and flatness of 0.01mm. The ball-head locating pin is made of CrWMn tool steel, with overall quenching treatment and grinding to ensure dimensional accuracy and a surface roughness of Ra0.4.

[0022] During operation, adjust the centering jaws to the appropriate position. Both forward and reverse jaws can be used, depending on the actual part specifications. Then, install the three ball-head locating pins into the locating pin holes below the part, place the part in contact with the ball-head locating pins, and use the precision chuck to center the part. There is no need to apply force to prevent the part from deforming. Adjust the bolts behind the pressure plate to the appropriate position to ensure that the pressure plate is horizontal. The pressure plate should be placed directly above the ball-head locating pins to press the part firmly.

Claims

1. A universal fixture for machining turbine pump housings, characterized in that: The system includes a base (1), a precision chuck (2), a base plate (3), three sets of movable sliders (4), three centering jaws (5), and three pressure plates (6); the base (1) has six countersunk holes A (101) evenly spaced along the circumference; the precision chuck (2) has three sets of slides (22) spaced at 120° intervals and six countersunk holes B (21) evenly spaced along the circumference; the base plate (3) has three sets of clearance slots (34) spaced at 120° intervals and three rows of positioning pin holes (32), and six countersunk holes C (31) evenly spaced along the circumference; the upper surface of each set of movable sliders (4) has two positioning grooves A (42) downward along the width direction, and the upper surface is machined into a positioning boss A (43) along the length direction, with two side surfaces along the width direction. A sliding groove (41) is opened along the length direction, and four threaded holes B (44) are opened on the upper surface of the movable slider (4); the top surface of each centering claw (5) is arranged from high to low as step one (51), step two (52) and step three (53), and countersunk holes D (54) and E (55) are opened on step one (51) and step three (53) respectively. The bottom surface of the centering claw (5) is machined into a positioning boss B (56) along the width direction, and a positioning groove B (57) is machined along the length direction. Both end faces of the centering claw (5) are rounded. The centering claw (5) can be rotated 180° for installation and can be internally supported or externally clamped; a set of waist-shaped through grooves (61) and a threaded through hole (62) are opened along the length direction on each of the pressure plates (6).

2. The universal fixture for machining turbine pump housings according to claim 1, characterized in that: Each row of positioning pin holes (32) contains nine holes, all with internal threads, for mounting the pressure plate (6) and the ball-head positioning pin (7).

3. The universal fixture for machining turbine pump housings according to claim 1, characterized in that: The slide rail (22) is machined into a tooth shape, and the bottom surface of the movable slider (4) is machined into a matching tooth shape.

4. The universal fixture for machining turbine pump housings according to claim 1, characterized in that: The two ends of the first step (51), the second step (52) and the third step (53) are all machined into a tooth shape.

5. The universal fixture for machining turbine pump housings according to claim 1, characterized in that: The front end of the pressure plate (6) is processed into a shrink head, which abuts against the shell.

6. The universal fixture for machining turbine pump housings according to claim 1, characterized in that: When the pressure plate (6) presses the housing, the bolt C (10) is screwed into the waist-shaped through groove (61) and the positioning pin hole (32) to tighten and lock it, and the bolt D (11) is screwed into the positioning pin hole (32) inverted to adjust the height.

7. The universal fixture for machining turbine pump housings according to claim 1, characterized in that: The movable slider (4) and the centering claw (5) are connected by screwing the bolt B (9) into the countersunk hole D (54) and the threaded hole B (44), and the countersunk hole E (55) and the threaded hole B (44).

8. The universal fixture for machining turbine pump housings according to claim 1, characterized in that: The positioning boss A (43) matches the positioning groove B (57); the positioning boss B (56) matches the positioning groove A (42).

9. The universal fixture for machining turbine pump housings according to claim 1, characterized in that: The slide (22) is machined into a groove in the radial direction inside, which matches the sliding groove (41) of the movable slider (4).

10. The universal fixture for machining turbine pump housings according to claim 1, characterized in that: The base (1) and the precision chuck (2) are installed by screwing bolts A (8) into countersunk holes A (101) and B (21) respectively.

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