A coaxiality improving counterbore positioning fixture and method

Abstract

The application discloses a positioning clamp and method for improving coaxiality of a matched drill hole, and the positioning clamp comprises a fixed clamp base, a gasket and a locking nut, wherein the fixed clamp base comprises a threaded screw rod, a positioning step and a head in a coaxial connection, the height of the positioning step is slightly lower than the thickness of an outer adjusting sheet, and the outer adjusting sheet is ensured to be in surface contact with a reinforcing rib. During positioning, the outer adjusting sheet is in surface contact with the fixed clamp base. The threaded screw rod is matched with the gasket and the locking nut, the outer adjusting sheet and the reinforcing rib are pressed by screwing the locking nut, and the gasket is in surface contact with the reinforcing rib. The coaxiality between the outer adjusting sheet and the reinforcing rib can be quickly determined by the positioning step and the threaded screw rod on the fixed clamp base, and then the position of the matched drill hole is determined, the machining efficiency is improved, and the machining time is saved.

Description

Technical Field

[0001] This invention belongs to the field of machining technology, and in particular, it relates to a method and fixture for quickly determining the positioning of drill holes during the drilling process. Background Technology

[0002] like Figure 1 and Figure 2 As shown, the outer adjustment plate 1, based on composite materials, is one of the important components in an aero-engine. Its shape consists of a rectangle and an isosceles triangle located on one side of the rectangle. Because the outer adjustment plate 1 is made of sheet metal, its rigidity is relatively poor, making it unsuitable for the assembly of overall aero-engine components. To increase its rigidity, the outer adjustment plate 1 is typically overlapped with reinforcing ribs 2 to form an outer adjustment plate assembly, thereby increasing its rigidity. Figure 2 The reinforcing rib 2 is an isosceles trapezoid with a weight-reducing groove, which is also an isosceles trapezoid.

[0003] The outer adjusting plate 1 and the reinforcing rib 2 are connected and fixed by threads, therefore, matching drill holes are required for the outer adjusting plate 1 and the reinforcing rib 2. Currently, the actual on-site matching drill hole machining involves overlapping the outer adjusting plate 1 and the reinforcing rib 2, clamping the overlapping outer adjusting plate 1 and the reinforcing rib 2 with two bolt cutters, and then performing matching drill hole machining. The machining state is as follows. Figure 2 As shown. The current method produces poor fit of the holes, which easily leads to poor coaxiality between the outer adjusting piece 1 and the reinforcing rib 2, resulting in poor assembly effect. In severe cases, it can cause the outer adjusting piece assembly to be scrapped, resulting in significant economic losses. Summary of the Invention

[0004] The present invention aims to provide a positioning fixture and method for drilling holes to improve coaxiality, ensuring that the coaxiality of each hole after the outer adjusting plate and the reinforcing rib are drilled meets the assembly requirements, avoiding poor coaxiality and poor assembly effect due to inaccurate clamping and positioning, reducing scrap and economic losses, and the positioning method and positioning fixture are simple to implement.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A drilling positioning fixture for improving coaxiality, used for positioning the outer adjusting plate and reinforcing rib, comprising: The fixed clamp base includes a head and a threaded screw connected coaxially. The minimum outer diameter of the head is greater than the maximum outer diameter of the threaded screw. The threaded screw includes a smooth cylindrical section and a threaded section. The smooth cylindrical section is connected to the head. A circular positioning step, coaxial with the smooth cylindrical section, is provided on the connection interface between the head and the smooth cylindrical section. The outer diameter of the positioning step is equal to the diameter of the first positioning hole on the outer adjusting plate. The axial height of the positioning step is less than the thickness of the outer adjusting plate. The outer diameter of the smooth cylindrical section is equal to the diameter of the second positioning hole on the reinforcing rib. The gasket is an annular gasket with an outer diameter larger than the outer diameter of the positioning step and an inner diameter between the outer and inner diameters of the positioning step. The gasket is fitted onto the threaded screw. A locking nut is connected to the threaded section of a threaded screw and restricts a washer between the locking nut and the positioning step. The maximum outer diameter of the locking nut is between the inner and outer diameters of the washer.

[0006] As one embodiment, the head of the fixed clamp base is a rotating body, and the end faces at both ends of the rotating body's axis of rotation are both planes.

[0007] A method for improving coaxiality through a pre-drilled hole positioning fixture, used for positioning an outer adjusting plate and a reinforcing rib, employing the aforementioned pre-drilled hole positioning fixture, and comprising: Step 1: Machining a first positioning hole on the outer adjusting plate and a second positioning hole on the reinforcing rib, wherein the diameter of the first positioning hole is larger than the diameter of the second positioning hole, the center of the first positioning hole is located on the axis of symmetry of the outer adjusting plate, and the center of the second positioning hole is located on the axis of symmetry of the reinforcing rib. Step two: Align the outer adjusting plate and the reinforcing rib according to their respective axes of symmetry and overlap them together, aligning the first positioning hole with the second positioning hole. Then, insert the threaded screw of the fixing fixture base into the first positioning hole and the second positioning hole, wherein: The positioning step forms a hole-shaft fit with the first positioning hole; A hole-shaft fit is formed by the second positioning hole in the smooth cylindrical section of the threaded screw; The axial height of the positioning step is less than the thickness of the outer adjusting plate to ensure that the outer adjusting plate and the reinforcing rib are in surface contact. Insert a washer onto the threaded screw, and then screw the locking nut onto the threaded section of the threaded screw until the locking nut presses the washer against the surface of the reinforcing rib. At this point, the outer adjusting plate and the reinforcing rib are clamped together. Step 3: Use bolt clamps to hold the outer adjusting plate and the reinforcing rib. The clamping point of the bolt clamps with the outer adjusting plate is located on the axis of symmetry of the outer adjusting plate, and the clamping point of the bolt clamps with the reinforcing rib is located on the axis of symmetry of the reinforcing rib. The distance from the clamping point of the bolt clamps with the outer adjusting plate to the center of the first positioning hole is equal to the distance from the clamping point of the bolt clamps with the reinforcing rib to the center of the second positioning hole.

[0008] As one approach, in step one, the distance between the two parallel sides of the outer adjustment piece is obtained based on the dimensional information in the drawing of the outer adjustment piece. The position corresponding to half of this distance is taken as the position of the axis of symmetry, and a first positioning hole is machined on the axis of symmetry. Similarly, the length of the bottom edge of the reinforcing rib is obtained based on the dimensional information in the drawing of the reinforcing rib. The position corresponding to half of this length is taken as the position of the axis of symmetry, and a second positioning hole is machined on the axis of symmetry.

[0009] As one possible approach, in step three: Based on the dimensional information in the drawing of the outer adjustment plate, obtain the distance L1 from the center of the first positioning hole to one of the two parallel sides on the outer adjustment plate; Based on the dimensional information in the reinforcing rib drawing, obtain half of the length of the top edge of the reinforcing rib, denoted as L2. Determine the clamping point of the clamping pliers by measuring whether the distance L3 from both ends of the top edge of the reinforcing rib to the two parallel sides on the outer adjusting plate is equal to L1-L2.

[0010] Compared with the prior art, the positioning fixture and positioning method of the present invention have the following characteristics: (1) The present invention can quickly determine the coaxiality between the outer adjusting plate and the reinforcing rib by fixing the positioning step and the threaded screw on the fixture base, thereby determining the position of the drilling hole, improving processing efficiency and saving processing time; (2) In this invention, the outer adjusting plate and the reinforcing rib are fixed and positioned by positioning steps and threaded screws, which avoids slippage between the outer adjusting plate and the reinforcing rib due to force, thereby ensuring the coaxiality of the drilling position between the outer adjusting plate and the reinforcing rib, thus avoiding the problem of scrapping the outer adjusting plate assembly during processing and saving processing costs. Attached Figure Description

[0011] Figure 1 This is a simplified schematic diagram of the external adjustment plate and reinforcing ribs; Figure 2 This is a schematic diagram of the existing external adjustment plate assembly processing method; Figure 3 This is a schematic diagram of the overall setup for the drilling positioning fixture; Figure 4 This is an exploded view of the drilling positioning fixture; Figure 5 This is a schematic diagram of the drilling positioning method. Figure 6 This is a cross-sectional view of the assembly of the drilling positioning fixture and the external adjusting plate; Figure 7 yes Figure 6 Enlarged view of key components for coaxiality positioning; Figure 8 This is a diagram showing the clamping position of the bolt clamps; In the diagram: 1. Reinforcing rib; 2. External adjusting plate; 3. Fixing fixture base; 4. Shim; 5. Threaded screw; 6. Locking nut; 7. Positioning step. Detailed Implementation

[0012] The present invention will be further described below with reference to specific embodiments, but it should not be construed as limiting the scope of the subject matter of the present invention to the following embodiments. All modifications, substitutions and alterations made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention are included within the scope of the present invention.

[0013] like Figure 3 and Figure 4 As shown, the present invention designs a fixture that can quickly determine the positioning of the matching drill hole, so as to improve the coaxiality of the matching drill hole between the outer adjusting plate 1 and the reinforcing rib 2, thereby greatly increasing the assembly success rate of the product.

[0014] The hole positioning fixture for improving coaxiality includes a fixed fixture base 3, a washer 4, a threaded screw 5, a locking nut 6, and a positioning step 7, which are achieved by the above components together.

[0015] The main body of the drilling positioning fixture for improving coaxiality is a fixed fixture base 1. The fixed fixture base 3 includes a head and a threaded rod 5 coaxially connected. The minimum outer diameter of the head is greater than the maximum outer diameter of the threaded rod 5. The threaded rod 5 includes a smooth cylindrical section and a threaded section. The smooth cylindrical section is connected to the head, and a circular positioning step 7, coaxial with the smooth cylindrical section, is provided on the connection interface between the head and the smooth cylindrical section. The outer diameter of the positioning step 7 is equal to the diameter of the first positioning hole on the outer adjusting plate 1, and the axial height of the positioning step 7 is less than the thickness of the outer adjusting plate 1. The outer diameter of the smooth cylindrical section is equal to the diameter of the second positioning hole on the reinforcing rib 2. The outer adjusting plate 1 and the reinforcing rib 2 are fixed by the fixed fixture base 1, and then the threaded rod 5 is fixed by using a locking nut 6.

[0016] like Figure 7 The height of the positioning step 7 is slightly lower than the thickness of the outer adjusting plate 1, ensuring that the outer adjusting plate 1 and the reinforcing rib 2 are in surface contact, and that the outer adjusting plate 1 and the base of the fixing fixture 3 are in surface contact. The threaded screw 5 cooperates with the washer 4 and the locking nut 6. By turning the locking nut 6, the outer adjusting plate 1 and the reinforcing rib 2 are pressed together, and the washer 4 and the reinforcing rib 2 are in surface contact.

[0017] The principle behind this invention to improve coaxiality: Using the fixture base 3 as the main body, first install the outer adjusting piece 1, ensuring that the thickness of the outer adjusting piece 1 is slightly higher than the thickness of the positioning step 7. Then install the reinforcing rib 2. Install a shim 4 on the reinforcing rib 2 to prevent the locking nut 6 from damaging the surface of the reinforcing rib 2 material. Install the locking nut 6 and engage it with the fixture threaded rod 5 to press the shim 4, thereby pressing the reinforcing rib 2 and the outer adjusting piece 1 together. The outer adjusting piece 1 and the reinforcing rib 2 are positioned coaxially by the positioning step 7 and the threaded rod 5 on the fixture base 1. Finally, the locking nut 6 engages with the fixture threaded rod 5 to fix the outer adjusting piece 1 and the reinforcing rib 2, ensuring the coaxiality between them is guaranteed by the positioning step 7 and the threaded rod 5. The other end of the outer adjusting piece 1 and the reinforcing rib 2 is fixed and tightened using a bolt cutter.

[0018] See Figures 3-8 A fixture for quickly determining the positioning hole of a drilled hole mainly consists of a fixed fixture base 3, a positioning step 7, a threaded screw 5, a washer 4, and a locking nut 6. The positioning method of the outer adjusting piece 1 and the reinforcing rib 2 is as follows: (1) Insert the outer adjustment piece 1 into the surface of the fixed fixture base 3, and the thickness of the outer adjustment piece 1 is slightly higher than the positioning step 7 to ensure that the outer adjustment piece 1 and the reinforcing rib 2 fit tightly together.

[0019] (2) The reinforcing rib 2 is installed into the base of the fixing fixture 1 through the threaded screw 5, and overlaps with the outer adjusting plate 1.

[0020] (3) Insert the gasket 4 onto the surface of the reinforcing rib 2 to prevent the locking nut 6 from directly contacting the reinforcing rib 2 and damaging the surface material of the reinforcing rib 2.

[0021] (4) The locking nut 6 and the threaded screw 5 cooperate, and the locking thread 6 moves downward, pushing the washer 4 to fix the outer adjusting piece 1 and the reinforcing rib 2, thereby ensuring the coaxiality of the drilling position between the two.

[0022] When using this clamp, such as Figure 5 The fixture base 1 is used to fix one end of the external adjusting plate assembly, ensuring that the two are coaxial in the position of the drilled holes. The other end is clamped using a bolt clamp. Compared with the existing method of using two bolt clamps for clamping, this avoids slippage between the two due to external forces under the current processing conditions, thereby avoiding the scrapping of parts during processing and saving processing costs.

[0023] Instructions for determining the clamping position of the other end of the clamping pliers: (The instructions are incomplete and require further context.) Figure 8 It can be seen that dimensions L1 and L2 can be obtained from the drawings, and dimension L3 can be obtained from L1-L2. Use calipers to measure the distance of L3, and then use pliers to clamp the overlapping outer adjusting piece 1 and reinforcing rib 2.

[0024] Contents not described in detail in this specification are prior art known to those skilled in the art. Although illustrative specific embodiments of the invention have been described above to facilitate understanding by those skilled in the art, it should be understood that the invention is not limited to the scope of the specific embodiments. Various modifications are readily apparent to those skilled in the art as long as they fall within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of this invention are protected.

Claims

1. A method for positioning a drilled hole to improve coaxiality, used for positioning an outer adjusting plate (1) and a reinforcing rib (2), characterized in that, The drilling positioning fixtures used include: The fixed clamp base (3) includes a head and a threaded screw (5) connected coaxially. The minimum outer diameter of the head is greater than the maximum outer diameter of the threaded screw (5). The threaded screw (5) includes a smooth cylindrical section and a threaded section. The smooth cylindrical section is connected to the head. A circular positioning step (7) coaxial with the smooth cylindrical section is also provided on the connection interface between the head and the smooth cylindrical section. The outer diameter of the positioning step (7) is equal to the diameter of the first positioning hole on the outer adjusting plate (1). The axial height of the positioning step (7) is less than the thickness of the outer adjusting plate (1). The outer diameter of the smooth cylindrical section is equal to the diameter of the second positioning hole on the reinforcing rib (2). Gasket (4), the gasket (4) is an annular gasket, its outer diameter is larger than the outer diameter of the positioning step (7), and its inner diameter is between the outer diameter and the inner diameter of the positioning step (7). The gasket (4) is fitted onto the threaded screw (5). A locking nut (6) is connected to the threaded section of the threaded screw (5) and restricts the washer (4) between the locking nut (6) and the positioning step (7). The maximum outer diameter of the locking nut (6) is between the inner diameter and the outer diameter of the washer (4). Location methods include: Step 1: A first positioning hole is machined on the outer adjusting plate (1), and a second positioning hole is machined on the reinforcing rib (2). The diameter of the first positioning hole is larger than the diameter of the second positioning hole. The center of the first positioning hole is located on the axis of symmetry of the outer adjusting plate (1), and the center of the second positioning hole is located on the axis of symmetry of the reinforcing rib (2). Step 2: Align the outer adjusting plate (1) and the reinforcing rib (2) along their respective axes of symmetry and overlap them together, aligning the first positioning hole with the second positioning hole. Then, insert the threaded screw (5) of the fixing fixture base (3) into the first positioning hole and the second positioning hole, wherein: The positioning step (7) forms a hole-shaft fit with the first positioning hole; A hole-shaft fit is formed by the second positioning hole of the smooth cylindrical section of the threaded screw (5); By ensuring that the axial height of the positioning step (7) is less than the thickness of the outer adjusting piece (1), the outer adjusting piece (1) and the reinforcing rib (2) are in surface contact. Insert the washer (4) onto the threaded screw (5), and then screw the locking nut (6) onto the threaded section of the threaded screw (5) until the locking nut (6) presses the washer (4) against the surface of the reinforcing rib (2). At this time, the outer adjusting piece (1) and the reinforcing rib (2) are clamped. Step 3: Use pliers to clamp the outer adjusting plate (1) and the reinforcing rib (2). The clamping point of the pliers and the outer adjusting plate (1) is located on the axis of symmetry of the outer adjusting plate (1), and the clamping point of the pliers and the reinforcing rib (2) is located on the axis of symmetry of the reinforcing rib (2). The distance between the clamping point of the pliers and the outer adjusting plate (1) and the center of the first positioning hole is equal to the distance between the clamping point of the pliers and the center of the second positioning hole.

2. The method for improving coaxiality of a drilled hole positioning according to claim 1, characterized in that: The head of the fixed clamp base (3) is a rotating body, and the end faces at both ends of the rotation axis of the rotating body are planes.

3. The method for improving coaxiality of a drilled hole positioning according to claim 1, characterized in that: In step one, the distance between the two parallel sides of the outer adjustment piece (1) is obtained according to the size information in the drawing of the outer adjustment piece (1). The position corresponding to half of the distance is taken as the position of the axis of symmetry, and the first positioning hole is machined on the axis of symmetry. Similarly, the length of the bottom edge of the reinforcing rib (2) is obtained according to the size information in the drawing of the reinforcing rib (2). The position corresponding to half of the length is taken as the position of the axis of symmetry, and the second positioning hole is machined on the axis of symmetry.

4. The method for improving coaxiality of a drilled hole positioning according to claim 1, characterized in that, In step three: Based on the dimensional information in the drawing of the outer adjustment piece (1), obtain the distance L1 from the center of the first positioning hole to one of the two parallel sides on the outer adjustment piece (1); According to the dimension information in the drawing of the reinforcing rib (2), obtain half of the length value of the top edge of the reinforcing rib (2), denoted as L2. Determine the clamping point of the pliers by measuring whether the distance L3 from the two ends of the top edge of the reinforcing rib (2) to the two parallel sides on the outer adjustment piece (1) is equal to L1-L2.

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