Small-diameter thin-wall cylinder expanding clamp and expanding method

Abstract

The application discloses a small-diameter thin-wall cylinder expanding clamp and an expanding method, and the expanding clamp comprises a bottom plate, a stand column, a sliding block, a first nut, a second nut and a guide block. The first nut and the second nut are in threaded connection with the stand column, the sliding block is slidably connected to the outer surface slope of the stand column through the guide block, and the sliding block is located between the first nut and the second nut. The application is suitable for the internal expansion of the thin-wall cylinder with a diameter less than 200mm during machining, can be used for effectively supporting the inner wall of the part during machining, reducing the supporting gap and reducing the machining deformation of the part.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine manufacturing technology, specifically relating to an expansion fixture and expansion method used for machining small-diameter thin-walled cylinders. Background Technology

[0002] Some thin-walled cylinders with a diameter of less than 200mm exist in aero engines. Conventional expansion jigs are usually cone-shaped expansion blocks, which can only be used for diameters of 400mm or more. However, conventional gap positioning jigs are not easy to position and support during processing, and they are prone to deformation during processing, resulting in a high scrap rate of finished products. Summary of the Invention

[0003] The present invention aims to provide a small-diameter thin-walled cylindrical expansion fixture and expansion method, which is suitable for thin-walled cylindrical bodies with a diameter of less than 200mm. It can be used to form support for the inner wall of the part during the processing, reduce the support gap, and reduce the deformation of the part.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A small-diameter thin-walled cylindrical expansion clamp includes a base plate, a column, a slider, a first nut, a second nut, and a guide block; The lower end of the column is detachably mounted on the base plate, and the upper end of the column is threadedly connected to the second nut. The first nut is threaded to the column and is located between the second nut and the base plate; The guide blocks are fixedly installed on the outer surface of the column, and multiple guide blocks are arranged symmetrically about the axis of the column. There are multiple sliders, each of which is guided by a guide block and slidably connected to the outer surface of the column. The slider is located between the first nut and the second nut, and the outer surfaces of the multiple sliders form an expansion surface.

[0005] As one embodiment, the upper end of the column is provided with a first threaded section that engages with the second nut for controlling the slider to slide downward. Below the first threaded section and on the outer surface of the column, there is a first inclined surface for positioning and supporting the slider. The first inclined surface is provided with a first positioning groove for positioning the guide block. The first positioning groove is provided with a threaded hole for connecting the guide block. Below the first positioning groove and on the outer surface of the column, there is a second threaded section that engages with the first nut for controlling the slider to slide upward.

[0006] Furthermore, there is a gap between adjacent sliders, the axial projection of the slider is fan-shaped, each slider has a plane as a support surface, a cylindrical segment above the plane, the cylindrical surface of the cylindrical segment as a positioning surface, a clearance tool is set at the intersection of the cylindrical segment and the plane for tool avoidance, the slider has a second inclined surface for sliding engagement with the first inclined surface of the column, and the slider has a second positioning groove for sliding engagement with the guide block.

[0007] Furthermore, the guide block is T-shaped and has a first symmetrical positioning surface. The first symmetrical positioning surface is slidably positioned with the second positioning groove of the slider. The guide block also has a second symmetrical positioning surface, which is statically positioned with the first positioning groove of the column.

[0008] Alternatively, the lower end of the column is positioned with the base plate via a stop and connected to the base plate with screws.

[0009] Alternatively, the number of sliders may be four, five, or six.

[0010] A method for bulging a small-diameter, thin-walled cylinder, using the aforementioned bulging fixture, includes the following steps: Step 1: First, unscrew the second nut and install the part to be expanded onto the plane of the slider. Then, screw the first nut down along the column, allowing the slider to move downwards under gravity. When the cylindrical section of the slider is completely in contact with the inner wall of the part to be expanded, screw the first nut down a further distance. At this point, screw the second nut down to press the slider tight until the part to be expanded is fully positioned and expanded. Step two: After disassembling the expanded part, first, screw the second nut off in the opposite direction to step one, then screw the first nut off in the opposite direction to step one so that the first nut moves upward and drives the slider to move upward together. At this time, the outer diameter of the expanded surface composed of multiple sliders shrinks, and the part is no longer expanded tightly, so the part can be taken out.

[0011] Currently, there are no expansion jigs for thin-walled cylinders with a diameter of less than 200mm. Cylindrical surface positioning jigs with clearance fit to the parts are generally used. Since small-diameter thin-walled parts are made by sheet metal welding, the diameter tolerance and roundness are generally around 1mm. This results in excessive clearance in conventional jigs, making it impossible to achieve effective positioning and support, and the parts are very easy to deform during processing.

[0012] This invention abandons the traditional conical (conical) bulging fixture design for large-diameter parts, and adopts a sloped (planar) sliding fit and double-nut operation scheme, making the bulging support and disassembly of parts more convenient. It is particularly suitable for the bulging clamping of small-diameter, thin-walled cylindrical parts, with good control of the bulging gap and good positioning and support effect. On the one hand, it is not easy to set the sliding groove on the conical surface in the traditional bulging fixture, and the T-slots on both the cone and the slider are difficult to machine. On the other hand, if it is a conical contact, the slider is not in full-surface contact during the up and down sliding process. Only when the working state and the diameter are the same, the conical surfaces of the cone and the slider are fully in contact. This setting will affect the positioning accuracy and the service life of the fixture. However, the sloped contact method ensures full contact no matter where the slider slides, and the positioning accuracy and force are always in the optimal state. Traditional conical expansion molds are complex in structure, consisting of a cone, a central stud, and a guide groove. The clamps designed for them are generally 400mm in diameter, so they are not suitable for clamps for small-diameter expansion molds (for expansion molds inside thin-walled cylinders with a diameter of less than 200mm).

[0013] This invention provides a simple expansion clamp for thin-walled cylindrical parts with a diameter less than 200mm, solving the problems of excessive clearance and poor positioning support when supporting and positioning small-diameter thin-walled cylindrical parts. It also avoids machining deformation caused by the lack of effective positioning support for such thin-walled small-diameter parts. The expansion clamp of this invention is easy to install and operate, and the part is also easy to remove after expansion. Attached Figure Description

[0014] Figure 1 This is a front view of a small-diameter, thin-walled cylindrical part. Figure 2 This is a front view of the expansion clamp of the present invention; Figure 3 This is a front view of the column in this invention; Figure 4 This is a top view of the column in this invention; Figure 5 This is the front view of the slider in this invention; Figure 6 This is a top view of the slider in this invention; Figure 7 This is the front view of the guide block in this invention; In the diagram, 1 is the base plate; 2 is the column; 3 is the slider; 4 is the first nut; 5 is the second nut; and 6 is the guide block. Detailed Implementation

[0015] 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.

[0016] like Figures 2-7 As shown, this invention provides a small-diameter thin-walled cylindrical expansion clamp, which includes a base plate 1, a column 2, a slider 3, a first nut 4, a second nut 5, and a guide block 6.

[0017] The column 2 is mounted on the base plate 1 through the stop, and the guide block 6 is connected to the positioning groove on the column 2. The first nut 4 and the second nut 5 are connected to the threaded section of the column 2 to push the slider 3 to slide up and down along the outer surface of the column 2.

[0018] like Figure 2 , Figure 3 and Figure 4 The column 2 has a threaded section 1a that can be screwed into the second nut 5 to control the slider 3 to slide downwards and lock the part to be expanded; the column 2 has an inclined surface 1b to position and support the slider 3 and ensure the expansion working size of the slider 3; the column 2 has a positioning groove 1c to position the guide block 6; the column 2 has a threaded hole 1d to connect and install the guide block 6 with a screw; the column 2 has a threaded section 1e that can be screwed into the first nut 4 to control the slider 3 to slide upwards and release the part that has been expanded.

[0019] like Figure 5 and Figure 6 The slider 3 has a plane 2a for supporting the end face of the part to be expanded; the slider 3 has a cylindrical section 2b for positioning the part to be expanded; a clearance tool is set at the intersection of the cylindrical section 2b and the plane 2a for tool avoidance during machining and other processes; the slider 3 has an inclined surface 2c for sliding with the inclined surface 1b of the column 2; the slider 3 has a positioning groove 2d for sliding with the guide block 6; there is a gap 2e between adjacent sliders 3; the slider 3 adopts a sector block divided into four / five / six equal parts; if there is no gap 2e between adjacent sliders 3, the slider 3 cannot slide upward.

[0020] like Figure 7 The guide block 6 has two symmetrical positioning surfaces 3a, which slide and position with the positioning groove 2d of the slider 3; the guide block 6 also has two symmetrical positioning surfaces 3b, which are statically positioned with the positioning groove 1c of the column 2.

[0021] like Figure 1 , Figure 2 As shown, when it is necessary to bulge a small-diameter thin-walled cylinder with a diameter less than 200mm, the following method shall be followed: Install Figure 1 When installing the part, first unscrew the second nut 5 at the upper end of the column 2 corresponding to the threaded section 1a, install the part to be expanded onto the plane 2a of the slider 3, screw the first nut 4 down and let the slider 3 move down together under gravity (i.e., under its own weight). When the cylindrical section 2b of the slider 3 is completely in contact with the inner wall of the part to be expanded, screw the first nut 4 down 1 / 3 turn. At this time, screw the second nut 5 down to press the slider 3 until the part is completely positioned and expanded, achieving gapless expansion.

[0022] When disassembling the parts, first screw on the second nut 5 to remove it, then screw on the first nut 4 to move it upwards, which will move the slider 3 upwards along with it. At this time, the outer diameter of the expansion shape formed by the cylindrical segments 2b of the multiple sliders 3 will shrink, and the parts will no longer be tightened. At this time, the parts can be easily removed.

[0023] 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 small-diameter, thin-walled cylindrical expansion clamp, characterized in that, It includes a base plate (1), a column (2), a slider (3), a first nut (4), a second nut (5), and a guide block (6); The lower end of the column (2) is detachably mounted on the base plate (1), and the upper end of the column (2) is threadedly connected to the second nut (5); The first nut (4) is threaded to the column (2) and is located between the second nut (5) and the base plate (1); The guide block (6) is fixedly installed on the outer surface of the column (2), and the multiple guide blocks (6) are arranged in a centrally symmetrical manner about the axis of the column (2); There are multiple sliders (3). Each slider (3) is guided by a guide block (6) and slidably connected to the outer surface of the column (2). The slider (3) is located between the first nut (4) and the second nut (5). The outer surfaces of the multiple sliders (3) form an expansion surface.

2. The small-diameter thin-walled cylindrical expansion clamp according to claim 1, characterized in that: The upper end of the column (2) is provided with a first threaded section that engages with the second nut (5) to control the slider (3) to slide downward. Below the first threaded section and on the outer surface of the column (2) is a first inclined surface for positioning and supporting the slider (3). The first inclined surface is provided with a first positioning groove for positioning the guide block (6). The first positioning groove is provided with a threaded hole for connecting the guide block (6). Below the first positioning groove and on the outer surface of the column (2) is a second threaded section that engages with the first nut (4) to control the slider (3) to slide upward.

3. The small-diameter thin-walled cylindrical expansion clamp according to claim 2, characterized in that: There is a gap between adjacent sliders (3). The axial projection of sliders (3) is fan-shaped. Each slider (3) has a plane as a support surface. A cylindrical section is provided above the plane. The cylindrical surface of the cylindrical section is used as a positioning surface. A blanking tool is provided at the intersection of the cylindrical section and the plane for tool avoidance. A second inclined surface is provided on slider (3) for sliding cooperation with the first inclined surface of column (2). A second positioning groove is provided on slider (3) for sliding cooperation with guide block (6).

4. The small-diameter thin-walled cylindrical expansion clamp according to claim 3, characterized in that: The guide block (6) is T-shaped and has a first symmetrical positioning surface. The first symmetrical positioning surface is slidably positioned with the second positioning groove of the slider (3). The guide block (6) also has a second symmetrical positioning surface, which is statically positioned with the first positioning groove of the column (2).

5. The small-diameter thin-walled cylindrical expansion clamp according to claim 1, characterized in that: The lower end of the column (2) is positioned with the base plate (1) through a stop and is connected to the base plate (1) by screws.

6. The small-diameter thin-walled cylindrical expansion clamp according to claim 1, characterized in that: The number of sliders (3) is four, five or six.

7. A method for bulging a small-diameter thin-walled cylindrical body, characterized in that, The expansion clamp as described in claim 1 is used, and includes the following steps: Step 1: First, unscrew the second nut (5), install the part to be expanded onto the plane of the slider (3), screw the first nut (4) down along the column (2), and let the slider (3) move down together under gravity. When the cylindrical section of the slider (3) is completely in contact with the inner wall of the part to be expanded, screw the first nut (4) down a distance. At this time, screw the second nut (5) down to press the slider (3) until the part to be expanded is completely positioned and expanded. Step 2: After disassembling the expanded part, firstly, screw the second nut (5) off in the opposite direction to step 1, and then screw the first nut (4) off in the opposite direction to step 1 so that the first nut (4) moves upward and drives the slider (3) to move upward together. At this time, the outer diameter of the expanded surface composed of multiple sliders (3) shrinks, and the part is no longer expanded and can be taken out.

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