A special mandrel for processing slender and thin-walled parts

Abstract

The invention discloses a special mandrel for processing slender thin-walled tube parts, including a mandrel body, the mandrel body including a left end, a middle section and a right end, the left end, the middle section and the right end are all cylindrical, the diameter of the left end is equal to the diameter of the right end and is smaller than the diameter of the middle section; the left end of the mandrel is provided with a left fastening device, and the right end of the mandrel is provided with a right fastening device; the mandrel body is coaxially provided with a plurality of elastic sleeves, the elastic sleeves include an inner elastic sleeve and an outer elastic sleeve, the inner elastic sleeve is coaxially sleeved on the mandrel body, and the outer elastic sleeve is coaxially sleeved on the inner elastic sleeve. The invention has high processing accuracy, compact and practical structure, good positioning accuracy and convenient operation.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical processing, in particular to a special mandrel for processing slender and thin-walled tube parts. Background Art

[0002] Thin-walled tube parts are widely used due to their good corrosion resistance, high high temperature strength, good heat radiation resistance, strong impact resistance, material saving and light weight. However, thin-walled tube parts are difficult to machine, and it is a difficult problem to ensure high machining accuracy in the field of machining, especially for slender thin-walled tube parts used in space nuclear power plants, which require higher precision and are more difficult to machine. There are several difficulties in machining thin-walled tube parts: 1) Thin-walled tube parts have a small elastic modulus, and are prone to large elastic deformation under the action of cutting force and clamping force, thus affecting the machining accuracy; 2) During the machining process, under the action of alternating cutting force, thin-walled tube parts are very likely to produce resonance that is not conducive to machining, leaving vibration marks on the machined surface, thereby affecting the surface roughness and dimensional accuracy of the workpiece; 3) Thin-walled tube parts have a large aspect ratio, which is prone to clamping deformation, making positioning difficult during machining and difficult to clamp. Summary of the invention

[0003] The purpose of the present invention is to provide a special mandrel for processing slender thin-walled tube parts to solve the above technical problems.

[0004] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a special mandrel for processing slender thin-walled tube parts, including a mandrel body, the mandrel body including a left end, a middle section and a right end, the left end, the middle section and the right end are all cylinders, the diameter of the left end is equal to the diameter of the right end and is smaller than the diameter of the middle section; the left end is provided with a left fastening device, and the right end is provided with a right fastening device; the mandrel body is coaxially sleeved with a plurality of elastic sleeves, the elastic sleeves include an inner elastic sleeve and an outer elastic sleeve, the inner elastic sleeve is coaxially sleeved on the mandrel body, and the outer elastic sleeve is coaxially sleeved on the inner elastic sleeve.

[0005] As a preferred technical solution: the outer surface of the inner elastic body is a conical surface, and the inner surface of the outer elastic sleeve is a conical surface.

[0006] As a preferred technical solution: the outer side of the left end portion is provided with a thread, the left fastening device is a left fastening nut, and the left fastening nut is matched and connected with the outer side thread of the left end portion.

[0007] As a preferred technical solution: the outer side of the right end portion is provided with a thread, the right fastening device is a right fastening nut, and the right fastening nut is matched and connected with the outer side thread of the right end portion.

[0008] As a preferred technical solution: the outer surface of the left fastening nut is a stepped structure, the stepped structure is divided into a first section and a second section, and the outer surface of the second section is a conical surface.

[0009] As a preferred technical solution: the inner hole of the right fastening nut is a stepped hole structure.

[0010] As a preferred technical solution: the surfaces of the inner elastic sleeve and the outer elastic sleeve are provided with a plurality of through grooves, wherein the through grooves are radial through grooves, one axial end of the through grooves is open and the other end does not reach the end surface.

[0011] As a preferred technical solution: tapered holes are provided at both ends of the core shaft body.

[0012] The beneficial effects of the present invention are: a special mandrel for processing slender thin-walled tube parts, compared with the traditional structure: 1) when processing slender thin-walled tube parts, the mandrel body is installed in the slender thin-walled tube parts to play a supporting role, thereby reducing the deformation of the slender thin-walled tube parts; 2) the elastic sleeve is an inner and outer layer structure, and tightening the fastening devices at both ends causes the elastic sleeve to generate a tensioning force, which acts between the slender thin-walled tube parts and the elastic sleeve and generates friction, which can increase the damping of the slender thin-walled tube parts processing system and effectively eliminate the influence of resonance; 3) the tensioning force can be controlled by the fastening structure and the elastic sleeve, and the matching clearance can be adjusted to meet the requirements of different processing accuracy; 4) the tapered holes at both ends of the mandrel body are used for machine tool clamping to improve the positioning accuracy of the workpiece, and the combination of the fastening nuts can eliminate the influence of clamping deformation on the processing accuracy of the workpiece; 5) the structure is compact, the clamping and disassembly are simple, and the operation is easy. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic cross-sectional view of the main body of the present invention;

[0014] Figure 2 It is a cross-sectional schematic diagram of the elastic sleeve of the present invention;

[0015] Figure 3 This is a schematic diagram of the structure of the inner elastic sleeve of the present invention;

[0016] Figure 4 It is a left side view of the inner elastic sleeve of the present invention;

[0017] Figure 5 This is a schematic diagram of the structure of the outer elastic sleeve of the present invention;

[0018] Figure 6 It is a left side view of the outer elastic sleeve of the present invention;

[0019] Figure 7 It is a cross-sectional schematic diagram of the left fastening device of the present invention;

[0020] Figure 8 is a cross-sectional schematic diagram of the right fastening device of the present invention;

[0021] In the figure: 1. Mandrel body, 1-1. Left end, 1-2. Middle section, 1-3. Right end, 1-4. Conical hole, 2. Slender thin-walled tube parts, 3. Inner elastic sleeve, 4. Outer elastic sleeve, 5. Left fastening device, 5-1. First section, 5-2. Second section, 6. Right fastening device, 6-1. Large hole, 6-2. Small hole, 7. Through groove DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with the accompanying drawings:

[0023] See also Figure 1-8 A special mandrel for processing slender thin-walled tube parts, comprising a mandrel body 1, the mandrel body 1 is a solid structure, the mandrel body 1 comprises a left end 1-1, a middle section 1-2 and a right end 1-3, the left end 1-1, the middle section 1-2 and the right end 1-3 are all cylindrical, the center lines of the left end 1-1, the middle section 1-2 and the right end 1-3 are coaxial, the diameter of the left end 1-1 is equal to the diameter of the right end 1-3 and is smaller than the diameter of the middle section 1-2; the left end 1-1 is provided with a left fastening device 5, and the right end 1-3 of the mandrel is provided with a right fastening device 6; the mandrel body 1 is coaxially provided with a plurality of elastic sections The elastic sleeve comprises an inner elastic sleeve 3 and an outer elastic sleeve 4. The inner elastic sleeve 3 is coaxially sleeved on the core shaft body 1, and the outer elastic sleeve 4 is coaxially sleeved on the inner elastic sleeve 3. This structure is arranged in the slender thin-walled tube part 2 and can support the slender thin-walled tube part 2. The slender thin-walled tube part 2 is clamped by tightening the left fastening device and the right fastening device, which can significantly reduce the deformation of the slender thin-walled tube part 2. Tightening the left fastening device and the right fastening device can also make the elastic sleeve generate a tightening force, thereby increasing the processing damping of the slender thin-walled tube part 2, effectively eliminating the influence of resonance, and improving the processing accuracy.

[0024] like Figure 1-8 As shown, the outer surface of the inner elastic sleeve 3 is a conical surface, the inner surface of the inner hole of the outer elastic sleeve 4 is a conical surface, the end of the inner elastic sleeve 3 with a larger outer diameter is the left end, and the end with a smaller outer diameter is the right end, the end of the outer elastic sleeve 4 with a larger inner diameter is the left end, and the end with a smaller inner diameter is the right end, and the conical surface structure can reduce the resistance of the inner elastic sleeve 3 entering the inner hole of the outer elastic sleeve 4, and make it difficult for the inner elastic sleeve 3 and the outer elastic sleeve 4 to loosen after the clearance is matched.

[0025] like Figure 1-8 As shown, a thread is arranged on the outer side of a section of the left end portion 1-1 close to the middle section 1-2, and the left fastening device 5 is a left fastening nut, which is matched and connected with the outer thread of the left end portion 1-1, and the left fastening nut can be tightly connected with the core shaft body 1 by tightening the left fastening nut.

[0026] like Figure 1-8 As shown, a thread is arranged on the outer side of a section of the right end portion 1-3 of the core shaft close to the middle section 1-2, and the right fastening device 6 is a right fastening nut, which is matched and connected with the outer thread of the right end portion 1-3, and the right fastening nut can be tightly connected with the core shaft body 1 by tightening the right fastening nut.

[0027] like Figure 1-8 As shown, the outer side of the left fastening nut is a stepped structure, and the stepped structure is divided into a first section 5-1 and a second section 5-2. The outer surface of the second section 5-2 is a conical surface. The outer diameter of the first section 5-1 is larger than the maximum outer diameter of the second section 5-2, and the maximum outer diameter of the second section 5-2 is not larger than the maximum outer diameter of the inner elastic sleeve 3. By tightening the left fastening nut, the conical surface is embedded in the inner hole of the outer elastic sleeve 4, and the end face of the second section 5-2 is against the left end face of the inner elastic sleeve 3, pushing the inner elastic sleeve 3 to move axially to the right.

[0028] like Figure 1-8 As shown, the inner hole of the right fastening nut is a stepped hole structure, and the stepped hole structure forms two holes of different diameters, the larger diameter is the large hole 6-1 and the smaller diameter is the small hole 6-2. The inner hole of the right fastening nut facing one end of the elastic sleeve is the large hole 6-1, and the diameter of the large hole 6-1 is not less than the minimum inner diameter of the outer elastic sleeve 4. By tightening the right fastening nut, one end of the large hole 6-1 of the right fastening nut presses against the end face of the outer elastic sleeve 4, pushing the outer elastic sleeve 4 to move axially to the left.

[0029] like Figure 1-8As shown, the surfaces of the inner elastic sleeve 3 and the outer elastic sleeve 4 are provided with a plurality of through grooves 7. Taking the inner elastic sleeve 3 as an example, the through grooves 7 are radial through grooves, which are evenly distributed on the sleeve wall of the inner elastic sleeve 3. One axial end of the through grooves 7 is open, and the other end does not reach the end surface. The number of through grooves 7 can be four, eight or twelve. By using wire cutting, half of the circumferentially evenly distributed through grooves 7 are first axially opened from the left end face of the inner elastic sleeve 3 to the right end of the inner elastic sleeve 3, and then the other half of the circumferentially evenly distributed through grooves 7 are axially opened from the right end face of the inner elastic sleeve 3 to the left end of the inner elastic sleeve 3. The structure of the through grooves 7 of the outer elastic sleeve 4 is the same as that of the through grooves 7 of the inner elastic sleeve 3. When the left fastening nut axially compresses the inner elastic sleeve 3, due to the surface of the inner elastic sleeve 3 A through groove 7 is provided so that the inner elastic sleeve 3 can be fully expanded radially to generate a tensioning force, which acts between the inner elastic sleeve 3 and the outer elastic sleeve 4 to make them clamped to each other. When the right fastening nut axially compresses the outer elastic sleeve 4, since the sleeve wall of the outer elastic sleeve 4 is provided with a through groove 7, the outer elastic sleeve 4 can be fully expanded radially to generate a tensioning force, which acts between the outer elastic sleeve 4 and the slender thin-walled tube-like parts 2 and generates friction, so that the slender thin-walled tube-like parts 2 rotate with the core shaft body 1 during turning. The deformation of the inner elastic sleeve 3 and the outer elastic sleeve 4 is adjusted by tightening the left fastening nut and the right fastening nut, thereby adjusting the fitting clearance between the outer elastic sleeve 4 and the inner wall of the slender thin-walled tube-like parts 2 to meet different processing accuracy requirements.

[0030] like Figure 1-8 As shown, the center holes at both ends of the mandrel body 1 are high-precision tapered holes 1-4. During machining, the machine tool adopts a clamping method of supporting the tapered holes 1-4 at both ends to improve the positioning accuracy of the mandrel body 1 on the machine tool.

[0031] The working process of this embodiment is as follows: when the workpiece is clamped, first, the left end fastening nut is sleeved on the left end portion 1-1 of the mandrel, and then the first section of the inner elastic sleeve 3 is sleeved from the right end of the mandrel body 1, and the inner elastic sleeve 3 is moved to the left end of the middle portion 1-2, and then the slender thin-walled tube-like parts 2 are sleeved from the left end of the mandrel body 1, and then the first section of the outer elastic sleeve 4 is installed from the right end of the mandrel body 1 and matched with the first section of the inner elastic sleeve 3. In this way, multiple sections of the inner elastic sleeve 3 and the outer elastic sleeve 4 are sleeved, and the slender thin-walled tube-like parts 2 are moved to the symmetrical positions at both ends of the mandrel middle section 1-2, and finally the left fastening nut is tightened. The left and right fastening nuts make the inner elastic sleeve 3 and the outer elastic sleeve 4 jammed with each other and generate a tensioning force to tighten the slender thin-walled tube parts 2 and the elastic sleeve to complete the clamping of the slender thin-walled tube parts 2; when the slender thin-walled tube parts 2 are disassembled, the left fastening nut and the right fastening nut are unscrewed, and the two nuts are swapped, with the right fastening nut at the left end and one end of the large hole 6-1 facing the elastic sleeve, and the left fastening nut at the right end and one end of the second section 5-2 of the left fastening nut facing the elastic sleeve, and the left fastening nut and the right fastening nut are gradually tightened to loosen the inner elastic sleeve 3 and the outer elastic sleeve 4.

[0032] The sizes of the mandrel body, the elastic sleeve, the left fastening nut and the right fastening nut and the number of sections of the elastic sleeve are all determined by the size of the thin-walled tube part.

[0033] The above embodiments are merely descriptions for the purpose of clearly illustrating the present invention, and are not limitations on the implementation methods. For those skilled in the art, other different forms of changes or modifications may be made based on the above descriptions. It is not necessary and impossible to enumerate all the implementation methods here, and the obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A special mandrel for processing slender thin-walled tube parts, comprising a mandrel body (1), wherein the mandrel body (1) comprises a left end portion (1-1), a middle section (1-2) and a right end portion (1-3), characterized in that: The left end portion (1-1), the middle section (12) and the right end portion (1-3) are all cylindrical, the diameter of the left end portion (1-1) is equal to the diameter of the right end portion (1-3) and is smaller than the diameter of the middle section (1-2), the left end portion (1-1) is provided with a left fastening device (5), and the right end portion (1-3) is provided with a right fastening device (6); the mandrel body (1) is coaxially sleeved with a plurality of sections of elastic sleeves, the elastic sleeves comprising an inner elastic sleeve (3) and an outer elastic sleeve (4), the inner elastic sleeve (3) is coaxially sleeved on the mandrel body (1), the outer elastic sleeve (4) is coaxially sleeved on the inner elastic sleeve (3), the outer surface of the inner elastic sleeve (3) is a conical surface, and the inner surface of the outer elastic sleeve (4) is a conical surface; The left fastening device (5) is a left fastening nut, the outer surface of the left fastening nut is a stepped structure, the stepped structure is divided into a first section (5-1) and a second section (5-2), the outer surface of the second section (5-2) is a conical surface, and the end surface of the second section (5-2) bears against the left end surface of the inner elastic sleeve (3); The right fastening device (6) is a right fastening nut, the inner hole of the right fastening nut is a stepped hole structure, and one end of the large hole (6-1) of the right fastening nut presses against the end surface of the outer elastic sleeve (4).

2. The special mandrel for processing slender thin-walled tube parts according to claim 1, characterized in that: The outer side of the left end portion (1-1) is provided with a thread, and the left fastening nut is matched and connected with the outer side thread of the left end portion (1-1).

3. The special mandrel for processing slender thin-walled tube parts according to claim 1, characterized in that: The outer side of the right end portion (1-3) is provided with a thread, and the right fastening nut is matched and connected with the outer side thread of the right end portion (1-3).

4. The special mandrel for processing slender thin-walled tube parts according to claim 1, characterized in that: The inner hole of the right fastening nut is a stepped hole structure.

5. The special mandrel for processing slender thin-walled tube parts according to claim 1, characterized in that: The surfaces of the inner elastic sleeve (3) and the outer elastic sleeve (4) are provided with a plurality of through grooves (7), wherein the through grooves (7) are radial through grooves, one axial end of the through grooves (7) is open and the other end does not reach the end surface.

6. The special mandrel for processing slender thin-walled tube parts according to claim 1, characterized in that: Conical holes (1-4) are provided at both ends of the core shaft body (1).

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