A clamping positioning tool and method for a heat shield

Abstract

The application discloses a clamping and positioning tool and method for a heat shield, and belongs to the technical field of aero-engine manufacturing. The tool comprises a base, a positioning plate, a positioning pin and a pressing plate assembly. The positioning plate is rotatably installed on the base, and the positioning pin is inserted into a positioning pin hole of the positioning plate, and a positioning head of the positioning pin is matched with a first connecting hole of the heat shield to realize accurate positioning. The pressing plate assembly is used for pressing the heat shield. The tool realizes quick and accurate positioning of the heat shield through accurate cooperation of the positioning pin and the first connecting hole, and completely eliminates the error of manual alignment. The rotatable positioning plate design effectively avoids machining interference, and the modular positioning pin design improves the universality of the tool. The application also provides a corresponding clamping and positioning method, and the machining efficiency and product quality are significantly improved, and the method is particularly suitable for batch machining of connecting holes of heat shields.

Description

Technical Field

[0001] This invention relates to the field of aero-engine manufacturing technology, and in particular to a clamping and positioning fixture and method for a heat shield. Background Technology

[0002] Combination Figure 1 and Figure 2 As shown, the heat insulation screen is formed by riveting the heat insulation sheet 2 and the arch frame 1 together with rivets 3. Before riveting, the arch frame 1 has been machined with 6 rivet holes 102 and a first connecting hole 101. After drilling the rivet holes 102 on the heat insulation sheet 2 through the rivet holes 102 on the arch frame 1, the heat insulation screen is formed by riveting. Then, the second connecting hole 201 on the heat insulation sheet 2 needs to be milled according to the contour of the first connecting hole 101 on the arch frame 1.

[0003] The problems encountered in actual processing are as follows: Before processing each part, the center position of the first connecting hole 101 needs to be manually aligned. The manual alignment is time-consuming, inefficient, and has low alignment accuracy.

[0004] In addition, the existing process still uses manual scribing and alignment, which is not only inefficient but also makes it difficult to guarantee accuracy, seriously affecting the processing quality and production efficiency of the products. Summary of the Invention

[0005] The main objective of this invention is to propose a clamping and positioning fixture and method for heat insulation screens, in order to solve the problems of low efficiency and poor accuracy of manual alignment in the prior art, and to achieve rapid and accurate positioning and clamping of heat insulation screens, thereby improving processing efficiency and product quality.

[0006] To achieve the above objectives, the present invention provides a clamping and positioning fixture for a heat insulation screen, comprising a base, a positioning plate, a positioning pin, and a pressure plate assembly. The positioning plate is rotatably mounted on the base. A positioning pin hole is provided on the positioning plate. The positioning pin is inserted into the positioning pin hole, and one end of the positioning pin is provided with a positioning head. The cross-sectional profile of the positioning head matches the shape of a first connecting hole on the heat insulation screen. The positioning head is used to insert into the first connecting hole to achieve precise positioning. The pressure plate assembly is mounted on the base and is used to press the heat insulation screen.

[0007] Preferably, a right boss is provided on the top surface of the right end of the base, the right boss being used to support the heat insulation screen to be processed; a plurality of clearance holes are provided on the top surface of the right boss to avoid rivets on the heat insulation screen.

[0008] Preferably, a limiting plane is provided on one side of the inner surface of the positioning pin hole, and a cylindrical surface is provided on the other side; a tangent plane is provided on the main body of the positioning pin, and an axial limiting step is formed at the end of the tangent plane away from the positioning head; when the positioning pin is inserted into the positioning pin hole, the limiting plane and the tangent plane fit together to form a blocking limit, which plays a role in preventing rotation, so as to ensure the angular orientation of the positioning pin and prevent the positioning pin from rotating around its own axis after assembly; the axial limiting step abuts against the top surface of the positioning plate, which plays a role in axial limiting.

[0009] Preferably, the positioning plate is rotatably mounted on the base via a connecting plate, a left boss, and a connecting screw; the left boss is integrally formed on the top surface of the left end of the base; a square groove is formed on the left boss, and countersunk through holes are formed on both side walls of the square groove; the connecting plate is welded to the bottom surface of the left end of the positioning plate; an ear block is integrally formed on the bottom surface of the left end of the connecting plate, and a screw hole is formed on the ear block; the connecting screw includes, in sequence, a screw head, a smooth section, and a threaded section; the ear block is installed in the square groove, and the connecting screw passes through the countersunk through hole and is threadedly connected to the ear block; the smooth section of the connecting screw is rotatably engaged with the countersunk through hole, and the threaded section of the connecting screw is screwed into the screw hole of the ear block.

[0010] Preferably, the lower part of the ear block is set as an arc surface to avoid interference with the bottom of the square groove when the ear block moves.

[0011] Preferably, two square positioning keys are provided on the bottom surface of the base for embedding into the T-slots of the machine tool worktable.

[0012] Preferably, the pressure plate assembly includes a double-ended screw, a locking nut, a pressure plate, and a support pin; a slotted hole is provided on the pressure plate; one end of the pressure plate is a pressing end and the other end is a supporting end, and a threaded through hole is provided on the supporting end of the pressure plate; the upper end of the support pin is screwed into the threaded through hole of the pressure plate; the lower end of the double-ended screw is screwed into the threaded blind hole of the base, and the upper end passes through the slotted hole of the pressure plate and is screwed with a locking nut.

[0013] Preferably, a pad is placed on the top surface of the base, and the lower end of the support nail abuts against the top surface of the pad.

[0014] Preferably, an opening groove is provided in the pressing section of the pressure plate, the width of the opening groove is greater than the width of the first connecting hole, and the opening groove is used to avoid the first connecting hole on the heat insulation screen.

[0015] Secondly, the present invention also provides a clamping and positioning method for a heat insulation screen, which uses the above-mentioned clamping and positioning fixture and includes the following steps: S1. Fix the clamping and positioning fixture onto the machine tool's worktable; S2. Insert the positioning pin into the positioning pin hole of the positioning plate; S3. Clamping the heat insulation screen: Place the heat insulation screen to be processed on the clamping and positioning fixture, rotate the positioning plate to make it parallel to the base, and make the positioning head at the lower end of the positioning pin insert into the first connecting hole of the heat insulation screen to form a positioning effect on the heat insulation screen; then use the pressure plate assembly to press the heat insulation screen tightly. S4. Establish a machining coordinate system with the central axis of the locating pin as the Z-axis; S5. Rotate the positioning plate so that the angle between it and the base is greater than 90°. S6. Process the second connection hole on the heat insulation screen; S7. Loosen the pressure plate assembly and remove the heat insulation screen.

[0016] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows: (1) The present invention achieves rapid and accurate positioning of the heat insulation screen by precisely matching the positioning pin with the first connecting hole, completely eliminating the error caused by manual alignment, and significantly improving the processing accuracy and consistency.

[0017] (2) The rotatable positioning plate design allows the milling cutter to easily avoid the machining area after positioning, providing ample operating space and effectively preventing interference during the machining process.

[0018] (3) By replacing the positioning pins with different shaped positioning heads, it can adapt to the processing of various models of heat insulation screens, which greatly improves the versatility and applicability of the tooling and reduces the tooling investment cost.

[0019] (4) The special structural design of the pressure plate assembly ensures the uniform distribution of the clamping force, while the opening slot effectively avoids the processing area, which not only ensures the reliability of the clamping, but also avoids processing interference. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a heat insulation screen; Figure 2 This is a schematic diagram of the bow frame structure; Figure 3 This is a schematic diagram of the clamping and positioning fixture provided by the present invention positioning and clamping the heat insulation screen. Figure 4This is a schematic diagram showing the position plate after the clamping and positioning fixture provided by the present invention clamps the heat insulation screen and then flips it over. Figure 5 for Figure 4 Top view; Figure 6 for Figure 5 BB section view; Figure 7 This is a schematic diagram of the base structure; Figure 8 This is a front view of the base; Figure 9 This is a structural schematic diagram of the positioning plate; Figure 10 This is a structural diagram of a locating pin; Figure 11 This is a schematic diagram of the pressure plate structure; Figure 12 This is a schematic diagram of the connecting screw.

[0022] Explanation of reference numerals: 1. Bow frame; 101. First connecting hole; 102. Rivet hole; 2. Heat insulation sheet; 201. Second connecting hole; 3. Rivet; 4. Locating pin; 401. Cutting plane; 402. Locating head; 403. Axial limiting step; 5. Locating plate; 501. Locating pin hole; 502. Ear block; 503. Screw hole; 504. Arc surface; 505. Connecting plate; 6. Connecting screw; 601. Smooth rod section; 602. Threaded section; 7. Double-ended screw; 8. Locking nut; 9. Pressure plate; 901. Open slot; 902. Threaded through hole; 903. Oblong hole; 10. Support pin; 11. Base; 111. Threaded blind hole; 112. Right boss; 113. Clearance hole; 114. Left boss; 115. Square groove; 116. Countersunk through hole; 117. Square locating key; 12. Spacer block. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0025] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0026] Combination Figure 1 and Figure 2 As shown, the heat insulation screen is formed by riveting the heat insulation sheet 2 and the arch frame 1 together with rivets 3. Before riveting, the arch frame 1 has been machined with 6 rivet holes 102 and a first connecting hole 101. After drilling the rivet holes 102 on the heat insulation sheet 2 through the rivet holes 102 on the arch frame 1, the heat insulation screen is formed by riveting. Then, the second connecting hole 201 on the heat insulation sheet 2 needs to be milled according to the contour of the first connecting hole 101 on the arch frame 1.

[0027] Combination Figures 3 to 12 As shown, this embodiment provides a clamping and positioning fixture for a heat insulation screen, including a base plate 11, a positioning plate 5, a positioning pin 4, and a pressure plate assembly.

[0028] The base 11 is a rectangular structure made of 45# steel through quenching and tempering, possessing good strength and rigidity. Two square locating keys 117 are provided on the bottom surface of the base 11. These keys can precisely embed into the T-slots of the CNC milling machine's worktable, enabling rapid positioning and fixing of the tooling. This positioning method not only improves clamping efficiency but also ensures precise alignment between the tooling and the machine tool, providing a reliable reference for subsequent machining.

[0029] A right boss 112 is integrally formed on the top surface of the right end of the base 11. This boss is precision milled with a flatness error of no more than 0.02mm, providing a stable and flat support surface for the heat insulation screen. Multiple clearance holes 113 are provided on the top surface of the right boss 112. These clearance holes 113 correspond to the positions of the rivets 3 on the heat insulation screen, effectively avoiding interference between the rivets 3 and the tooling, and ensuring that the heat insulation screen can be placed stably.

[0030] The positioning plate 5 is rotatably mounted on the base 11 via a connecting plate 505, a left boss 114, and connecting screws 6. The left boss 114 is integrally formed on the top surface of the left end of the base 11, and a square groove 115 is formed on the left boss 114. The square groove 115 is precision milled, and the dimensional tolerance is controlled within ±0.01mm. Countersunk through holes 116 are formed on both side walls of the square groove 115.

[0031] The connecting plate 505 is fixed to the bottom left side of the positioning plate 5 by welding. An ear block 502 is integrally formed on the bottom left side of the connecting plate 505. The lower part of the ear block 502 is machined into an arc surface 504. This design prevents the positioning plate 5 from interfering with the bottom of the square groove 115 during rotation. A screw hole 503 is provided on the ear block 502; this hole is tapped to ensure good thread quality.

[0032] The connecting screw 6 is made of 35CrMo material and has undergone heat treatment, giving it sufficient strength and wear resistance. The connecting screw 6 includes a screw head, a smooth shank section 601, and a threaded section 602. The lug 502 is installed in the square groove 115, and the connecting screw 6 passes through the countersunk hole 116 and is threaded into the lug 502. The smooth shank section 601 of the connecting screw 6 rotatably engages with the countersunk hole 116, with the clearance controlled between 0.01-0.02 mm, ensuring both flexibility of rotation and avoiding loss of positioning accuracy due to excessive clearance.

[0033] The positioning plate 5 has a positioning pin hole 501. A limiting plane 501a is provided on one side of the inner surface of the positioning pin hole 501, while the other side remains a cylindrical surface. This special design provides a reliable circumferential positioning reference for the positioning pin 4.

[0034] The locating pin 4 is made of GCr15 bearing steel, and after quenching and low-temperature tempering, its surface hardness reaches HRC60-62, exhibiting excellent wear resistance. A tangent plane 401 is machined onto the main body of the locating pin 4, and an axial limiting step 403 is formed at the end of the tangent plane 401 away from the locating head 402. When the locating pin 4 is inserted into the locating pin hole 501, the limiting plane 501a and the tangent plane 401 are tightly fitted, providing circumferential limiting for the locating pin 4. The axial limiting step 403 abuts against the top surface of the locating plate 5, providing circumferential limiting for the locating pin 4.

[0035] The positioning head 402 at the lower end of the positioning pin 4 is precisely manufactured according to the actual shape of the first connecting hole 101 on the heat insulation screen, with the contour tolerance controlled within ±0.005mm. This precise fit ensures that the heat insulation screen can return to the same position each time it is clamped, completely eliminating the error of manual alignment.

[0036] The pressure plate assembly includes a double-ended screw 7, a locking nut 8, a pressure plate 9, and a support pin 10. A slotted hole 903 is provided on the pressure plate 9; this design allows the pressure plate 9 to be adjusted within a certain range to accommodate heat insulation screens of different sizes. One end of the pressure plate 9 is a pressing end, and the other end is a supporting end; a threaded through hole 902 is provided on the supporting end of the pressure plate 9.

[0037] The upper end of the support pin 10 is screwed into the threaded through hole 902 of the pressure plate 9. The support height is adjusted by adjusting the screwing depth of the support pin 10. The lower end of the double-ended screw 7 is screwed into the threaded blind hole 111 of the base 11, and the upper end passes through the oblong hole 903 of the pressure plate 9 and is screwed with a locking nut 8. A pad 12 is placed on the top surface of the base 11, and the lower end of the support pin 10 abuts against the top surface of the pad 12.

[0038] An opening groove 901 is provided in the pressing section of the pressure plate 9. The width of the opening groove 901 is greater than the width of the first connecting hole 101. This design effectively avoids the area of ​​the first connecting hole 101 on the heat insulation screen and prevents interference between the pressure plate 9 and the processing area.

[0039] Secondly, this embodiment also provides a clamping and positioning method for a heat insulation screen, which uses the above-mentioned clamping and positioning fixture and includes the following steps: S1. Fix the clamping and positioning fixture onto the machine tool's worktable; S2. Insert the positioning pin 4 into the positioning pin hole 501 of the positioning plate 5; S3. Clamping the heat insulation screen: Place the heat insulation screen to be processed on the clamping and positioning fixture, rotate the positioning plate 5 to make it parallel to the base 11, and make the positioning head 401 at the lower end of the positioning pin 4 insert into the first connecting hole 101 of the heat insulation screen to form a positioning effect on the heat insulation screen; then use the pressure plate assembly to press the heat insulation screen. S4. Establish a machining coordinate system with the central axis of the locating pin 4 as the Z-axis; S5. Rotate the positioning plate 5 so that the angle between it and the base 11 is greater than 90°. S6. Process the second connecting hole 201 on the heat insulation screen; S7. Loosen the pressure plate assembly and remove the heat insulation screen.

[0040] The specific work process is as follows: First, the clamping and positioning fixture is precisely installed on the CNC milling machine worktable using the positioning key 117 on the base 11, and the base 11 is fixed using the pressure plate on the machine tool worktable. Then, the positioning pin 4 is inserted into the positioning pin hole 501 of the positioning plate 5, and circumferential positioning is achieved through the cooperation of the limiting plane 501a and the cutting plane 401, so that the axial limiting step 403 abuts against the top surface of the positioning plate 5.

[0041] Next, the heat insulation screen to be processed is placed on the right protrusion 112 of the base 11, and the positioning plate 5 is rotated to make it parallel to the base 11. At this time, the positioning head 402 at the lower end of the positioning pin 4 is precisely inserted into the first connecting hole 101 of the heat insulation screen to achieve precise positioning. Subsequently, the heat insulation screen is reliably pressed by the pressure plate assembly.

[0042] When establishing the machining coordinate system, the central axis of the locating pin 4 is used as the Z-axis reference. Due to the precise fit between the locating pin 4 and the first connecting hole 101, the machining coordinate system is accurately aligned with the actual position of the part.

[0043] Before starting machining, rotate the positioning plate 5 so that the angle between it and the base 11 is greater than 90° to provide sufficient operating space for the milling cutter and effectively avoid machining interference. Then, machine the second connecting hole 201 on the heat insulation screen according to the preset program. After machining, loosen the pressure plate assembly and remove the workpiece.

[0044] Through the above structure and process, the present invention achieves rapid and accurate positioning and efficient processing of heat insulation screens, significantly improving production efficiency and product quality, and providing reliable technical support for mass production.

[0045] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A clamping and positioning fixture for a heat insulation screen, characterized in that, Includes a base (11), a positioning plate (5), a positioning pin (4), and a pressure plate assembly; The positioning plate (5) is rotatably mounted on the base (11); The positioning plate (5) is provided with a positioning pin hole (501); the positioning pin (4) is inserted into the positioning pin hole (501), and one end of the positioning pin (4) is provided with a positioning head (402). The cross-sectional profile of the positioning head (402) matches the shape of the first connecting hole (101) on the heat insulation screen. The positioning head (402) is used to be inserted into the first connecting hole (101). The pressure plate assembly is mounted on the base (11) and is used to press the heat insulation screen; A limiting plane (501a) is provided on one side of the inner hole surface of the positioning pin hole (501), and a cylindrical surface is provided on the other side; The main body of the positioning pin (4) is provided with a cutting plane (401), and the end of the cutting plane (401) away from the positioning head (402) forms an axial limiting step (403). When the positioning pin (4) is inserted into the positioning pin hole (501), the limiting plane (501a) and the cutting plane (401) fit together to form a blocking limit; the axial limiting step (403) abuts against the top surface of the positioning plate (5); The positioning plate (5) is rotatably mounted on the base (11) via the connecting plate (505), the left boss (114) and the connecting screw (6); The left boss (114) is integrally formed on the top surface of the left end of the base (11); a square groove (115) is provided on the left boss (114), and countersunk through holes (116) are provided on the two side walls of the square groove (115). The connecting plate (505) is welded to the bottom left side of the positioning plate (5); an ear block (502) is integrally formed on the bottom left side of the connecting plate (505), and a screw hole (503) is provided on the ear block (502). The connecting screw (6) includes, in sequence, a screw head, a smooth section (601), and a threaded section (602). The ear block (502) is installed in the square groove (115), and the connecting screw (6) passes through the countersunk hole (116) and is threaded to the ear block (502); the smooth section (601) of the connecting screw (6) is rotatably engaged with the countersunk hole (116), and the threaded section (602) of the connecting screw (6) is screwed into the screw hole (503) of the ear block (502).

2. The clamping and positioning fixture according to claim 1, characterized in that, A right boss (112) is provided on the top surface of the right end of the base (11), which is used to support the heat insulation screen to be processed; a plurality of clearance holes (113) are provided on the top surface of the right boss (112) to avoid the rivets (3) on the heat insulation screen.

3. The clamping and positioning fixture according to claim 1, characterized in that, The lower part of the ear block (502) is configured as an arc surface (504).

4. The clamping and positioning fixture according to claim 1, characterized in that, Two square positioning keys (117) are provided on the bottom surface of the base (11) for embedding into the T-slot of the machine tool table.

5. The clamping and positioning fixture according to claim 1, characterized in that, The pressure plate assembly includes a double-headed screw (7), a locking nut (8), a pressure plate (9), and a support pin (10). A waist-shaped hole (903) is provided on the pressure plate (9); one end of the pressure plate (9) is a pressing end and the other end is a supporting end, and a threaded through hole (902) is provided on the supporting end of the pressure plate (9). The upper end of the support pin (10) is screwed into the threaded through hole (902) of the pressure plate (9); The lower end of the double-ended screw (7) is screwed into the threaded blind hole (111) of the base (11), and the upper end passes through the waist-shaped hole (903) of the pressure plate (9) and is screwed with a lock nut (8).

6. The clamping and positioning fixture according to claim 5, characterized in that, A pad (12) is placed on the top surface of the base (11), and the lower end of the support nail (10) abuts against the top surface of the pad (12).

7. The clamping and positioning fixture according to claim 5, characterized in that, An opening groove (901) is provided at the pressing end of the pressure plate (9). The width of the opening groove (901) is greater than the width of the first connecting hole (101). The opening groove (901) is used to avoid the first connecting hole (101) on the heat insulation screen.

8. A method for clamping and positioning a heat insulation screen, characterized in that, The clamping and positioning fixture according to any one of claims 1 to 7 includes the following steps: S1. Fix the clamping and positioning fixture onto the machine tool's worktable; S2. Insert the positioning pin (4) into the positioning pin hole (501) of the positioning plate (5); S3. Clamping the heat insulation screen: Place the heat insulation screen to be processed on the clamping and positioning fixture, rotate the positioning plate (5) to make it parallel to the base (11), and make the positioning head (402) at the lower end of the positioning pin (4) insert into the first connecting hole (101) of the heat insulation screen to form a positioning effect on the heat insulation screen; then use the pressure plate assembly to press the heat insulation screen. S4. Establish a machining coordinate system with the central axis of the positioning pin (4) as the Z-axis; S5. Rotate the positioning plate (5) so that the angle between it and the base (11) is greater than 90°; S6. Machining the second connecting hole (201) on the heat insulation screen; S7. Loosen the pressure plate assembly and remove the heat insulation screen.

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