Thin-wall cylindrical part inner hole grinding, positioning and clamping device and clamping method

Abstract

The invention discloses a thin-wall cylindrical part inner hole grinding, positioning and clamping device and a clamping method.The device is provided with a clamping shaft with a connecting shaft and a circular groove to clamp a cylinder, the inner side of the opening end of the circular groove is provided with an inwards-concave annular stop face, the outer side of the opening end of the circular groove is provided with an annular end face, and a middle pad comprising two semi-arc liners is arranged; the gasket is provided with a semi-arc boss and a semi-arc pressing wall and is further provided with a pressing threaded sleeve provided with a threaded sleeve, an annular limiting table and a limiting sleeve, and primary axial positioning is conducted from the two faces of the protruding edge of the thin-wall cylinder through an inwards-concave annular stop face and the semi-arc boss. The compression screw sleeve is screwed in the circular groove, the joint of the middle pad and the barrel is compressed in the radial direction and the axial direction, and then the barrel is subjected to centering adjustment and fastening through a plurality of adjusting bolts and check nuts which are arranged on the compression screw sleeve in a penetrating mode. According to the method, enough friction force can be provided for rotation of the thin-wall cylindrical part, harmful deformation of the thin-wall cylindrical part can be avoided, positioning is accurate, and dismounting and mounting are convenient.

Description

Technical Field

[0001] The invention belongs to the technical field of parts processing tools, and in particular relates to a grinding positioning clamping device and a clamping method for inner holes of thin-walled cylindrical parts. Background Art

[0002] Most accumulator cylinders are thin-walled cylindrical parts. During the use of the accumulator, the internal piston frequently reciprocates, causing deep scratches on the inner surface of the cylinder, resulting in leakage failures and failure to guarantee the performance of the accumulator. In order to repair the scratches on the inner surface, the inner surface needs to be ground and plated. Traditional grinding uses the copper pad of the machine tool soft claw pad to directly clamp and fix, which will cause the outer circle of the thin-walled cylinder to be subjected to pressure at three or four soft claw clamping points. The machine tool clamping requires a certain clamping force to ensure the reliability of the clamping, which may cause harmful deformation of the thin-walled cylinder at the clamping point, resulting in large errors during the grinding process, and even causing the parts to be scrapped. Specifically, the machine tool needs to maintain a certain clamping force when clamping thin-walled cylindrical parts, so that sufficient friction can be generated to drive the parts to rotate together. Since the friction force f is in direct proportion to the clamping force (clamping force) F, f = k (friction coefficient) * F, and when the friction force f is constant, the clamping force (clamping force) F acting on a single point also remains constant; according to P (pressure) = F (pressure) / S (force area), the force area clamped by the soft claw is small, so the pressure is very large, which makes it easy for thin-walled cylindrical parts to produce plastic deformation at the clamping point, resulting in the scrapping of parts. The prior art clamps the outer circle of the thin-walled cylindrical part with the machine tool soft claw, and generates sufficient friction on the outer circle by increasing the clamping force, so as to drive the thin-walled cylindrical part to rotate. Since the machine tool soft claw only applies clamping force to the corresponding point of the outer circle of the thin-walled cylindrical part, according to the proportional relationship between the friction force f and the clamping force (clamping force) F, the greater the friction required to drive the outer circle to rotate, the greater the clamping force applied by the soft claw to the thin-walled outer circle. This traditional clamping method has the following disadvantages: (1) The machine tool soft jaw clamping is a single-point force, which is easy to cause part deformation; (2) Grinding and plating in the case of deformation will cause irreversible damage, resulting in the scrapping of parts. This clamping method is only suitable for parts with solid interior or thick enough walls, and is not suitable for thin-walled cylindrical parts. In order to overcome the above defects, ensure the quality of part grinding and reduce resource waste, it is urgent to improve the clamping device. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a positioning clamping device and a clamping method for inner hole grinding of thin-walled cylindrical parts, which has firm clamping, does not cause harmful deformation, and is easy to adjust the center.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] The cam is an angular contact surface that is fixed with the cam face, and the cam face is connected with the cylindrical body to form a circle, and the cylindrical body is connected with the cylindrical body to form a circle. The cam is an annular retaining plate, and the cam is provided with an inner thread which cooperates with the outer thread, and the inner thread of ... inner thread

[0006] In the above-mentioned thin-walled cylindrical part inner hole grinding positioning clamping device, preferably, the connecting shaft is a hollow structure, and the interior of the connecting shaft is connected to the circular groove to realize the delivery of coolant and the discharge of grinding chips.

[0007] The above-mentioned thin-walled cylindrical part inner hole grinding positioning clamping device preferably also includes an annular gasket, which is used to increase the friction between the convex edge of the barrel mouth and the concave annular stop surface.

[0008] In the above-mentioned thin-walled cylindrical part inner hole grinding positioning clamping device, preferably, the annular gasket is a felt ring.

[0009] The above-mentioned thin-walled cylindrical part inner hole grinding positioning clamping device, preferably, also includes a bolt washer, and the bolt washer is located between the end of the adjusting bolt and the cylinder body when in use.

[0010] In the above-mentioned thin-walled cylindrical part inner hole grinding positioning clamping device, preferably, the bolt pad is copper sheet, and the thickness of the copper sheet is 0.5mm to 0.8mm.

[0011] In the above-mentioned thin-walled cylindrical part inner hole grinding positioning clamping device, preferably, the outer periphery of the clamping screw sleeve is provided with a wrench hole.

[0012] In the above-mentioned thin-walled cylindrical part inner hole grinding positioning clamping device, preferably, the middle pad is made of aluminum.

[0013] In the above-mentioned thin-walled cylindrical part inner hole grinding positioning clamping device, preferably, the length of the internal thread is greater than the length of the external thread.

[0014] In the above-mentioned thin-walled cylindrical part inner hole grinding positioning clamping device, preferably, a tool withdrawal groove is further provided in the compression screw sleeve, and the tool withdrawal groove is located between the threaded sleeve and the annular limit platform.

[0015] In the above-mentioned thin-walled cylindrical part inner hole grinding positioning clamping device, preferably, the ratio of the outer diameter to the inner diameter of the cylinder is less than or equal to 1.2.

[0016] As a general technical concept, the present invention also provides a clamping method based on the above-mentioned thin-walled cylindrical part inner hole grinding positioning clamping device, comprising the following steps:

[0017] S1. Clamp the clamp shaft onto the machine tool shaft through the connecting shaft, and adjust the position so that the clamp shaft is concentric with the machine tool shaft;

[0018] S2. Extend one end of the barrel with the convex edge into the circular groove, so that the end surface of the barrel mouth with the convex edge is in close contact with the concave annular stop surface, so as to preliminarily achieve the axial positioning of the barrel. The other end of the barrel is placed on the machine tool holder and kept horizontally.

[0019] S3, put two semicircular arc gaskets on the outside of the cylinder from both sides, so that the semicircular arc bosses extend along the outer wall of the cylinder to the back of the convex edge of the cylinder mouth, and press them inward manually;

[0020] S4, pass the compression screw sleeve through the cylinder, screw it onto the external thread of the clamping shaft and tighten it initially until the annular limit platform abuts against the semicircular arc compression wall to achieve axial positioning of the cylinder;

[0021] S5. Screw the tightening nut onto the adjusting bolt, and screw the adjusting bolt with the tightening nut into the threaded hole, so that the end of the adjusting bolt is in close contact with the outer wall of the cylinder;

[0022] S6. Start the machine tool and rotate it slowly, measure the runout of the outer circumference of the cylinder, and adjust the relative positions of multiple adjusting bolts and limit sleeves according to the runout detected initially to keep the cylinder and the machine tool concentric and achieve radial positioning. After the adjustment is completed, tighten the tightening nut to prevent the adjusting bolt from loosening;

[0023] S7. Tighten the clamping nut again to complete the clamping.

[0024] Compared with the prior art, the advantages of the present invention are:

[0025] (1) The present invention aims to solve the problem that during the grinding process of the inner surface of a thin-walled cylindrical part with a convex edge, the single-point clamping pressure is too large, resulting in deformation of the cylinder. The present invention creatively proposes a thin-walled cylindrical part inner hole grinding positioning clamping device, wherein a clamping shaft having a connecting shaft and a circular groove is provided to clamp the cylinder, an inner concave annular stop surface is provided on the inner side of the open end of the circular groove, and an annular end surface is maintained on the outer side, and a middle pad including two semicircular arc pads is provided, wherein the pads have a semicircular arc boss and a semicircular arc pressing wall, and a threaded The sleeve, annular limit platform and the clamping screw sleeve of the limit sleeve can achieve preliminary axial positioning of the thin-walled cylinder by clamping from both sides of the convex edge of the thin-walled cylinder mouth through the concave annular stop surface and the semicircular arc boss. Then the clamping screw sleeve is screwed into the connection between the circular groove, the middle pad and the cylinder body. The clamping screw sleeve and the circular groove are screwed in orderly through threaded engagement. During the screwing process, the annular limit platform applies axial thrust to the middle pad, so that the middle pad is further pressed against the convex edge of the cylinder mouth and the open end of the circular groove, thereby limiting the axial displacement of the cylinder. The clamping screw sleeve and the circular groove are threaded to radially and axially press the connection, and transmit this pressing force to the thin-walled cylinder, so that the cylinder and the clamping device generate sufficient clamping force to achieve reliable clamping. On this basis, the thin-walled cylinder is adjusted and tightened by a plurality of adjusting bolts and tightening nuts that are inserted into the clamping screw sleeve. The clamping device of the present invention can realize multiple axial and radial positioning and fastening of thin-walled cylindrical parts with convex edges. It has a clever design, is easy to clamp and disassemble, has high reliability, and is easy to adjust the center. The clamping device of the present invention converts the single-point pressure of the machine tool soft claw on the thin-walled cylinder into the surface pressure of the middle pad on the convex edge and the cylinder of the thin-walled cylinder, increases the force-bearing area, and can make the thin-walled cylinder evenly stressed. While improving the clamping friction, firmness and centering accuracy, it overcomes the harmful deformation caused by the single-point force of the soft claw clamping in the prior art. Furthermore, since the cylinder is positioned and clamped at the open end of the circular groove, a cavity is left at the end of the cylinder and the bottom of the circular groove to accommodate the grinding wheel ground to the end of the cylinder, and the inner diameter of the concave annular stop surface is greater than or equal to the inner diameter of the cylinder, so that the grinding wheel can easily pass through the thin-walled cylinder to reach the grinding wheel cavity, effectively ensuring uniform wear of the grinding wheel, and also ensuring uniform grinding of the inner wall of the thin-walled cylinder.

[0026] (2) The clamping device of the present invention adjusts the radial position of the barrel clamping by means of a plurality of adjusting bolts on the circumference of the clamping screw sleeve. The advantage is that the prior art requires the connection between the clamp and the machine tool to be disassembled and assembled again each time the barrel parts are processed in order to readjust the centering. The present invention does not require the disassembly and assembly of the connecting shaft, and does not require the alignment of the barrel parts and the rotating shaft to be achieved by readjusting the position of the connecting shaft and the rotating shaft of the machine tool. It only requires adjusting the adjusting bolts to achieve the required value of the barrel circumferential runout. The combination of the clamping screw sleeve and the adjusting bolt of the present invention is very convenient for adjusting the centering position of the clamping during the processing of large parts. The disassembly and assembly of the tooling during the processing of large parts is a process that wastes a lot of time and is prone to quality accidents. The clamping device of the present invention can effectively avoid problems in the process of disassembly and assembly of the tooling, while also reducing the workload.

[0027] (3) The clamping device of the present invention is particularly important for the clamping of thin-walled cylindrical parts for repair. In comparison, newly processed parts can be qualified as long as the operation is completed according to the process, while repair is the process of restoring unqualified parts to a qualified state. This has exceeded the normal processing process and requires adjustment of the clamping alignment according to the actual situation of the unqualified parts. It cannot be done overnight by copying and pasting. The clamping process is more difficult. The clamping device of the present invention can reduce the difficulty of clamping and centering of unqualified parts.

[0028] (4) In order to avoid the harmful deformation of the thin-walled outer cylinder caused by a sufficiently large pressure, the clamping method of the present invention converts the pressure direction from radial to axial. First, the axial positioning is performed through the cooperation of the middle pad, the open end of the circular groove and the clamping screw sleeve to achieve the preliminary fixation of the thin-walled cylindrical part. Then, the sliding adjustment and centering on the radial two-dimensional plane are achieved by screwing the adjusting bolt in and out, thereby improving the clamping accuracy of the thin-walled cylindrical part. Finally, the tightening nut is used to tighten the thin-walled cylindrical part. This can provide sufficient friction for the rotation of the thin-walled cylindrical part, meet the firmness of the clamping, and achieve the precision requirements of grinding positioning, and protect the thin-walled cylindrical part from deformation or even scrapping due to uneven force. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic structural diagram of a thin-walled cylindrical part inner hole grinding positioning clamping device according to Example 1 of the present invention.

[0030] Figure 2 This is a bottom view of the thin-walled cylindrical part inner hole grinding positioning clamping device according to embodiment 1 of the present invention.

[0031] Figure 3 for Figure 1 A magnified schematic diagram of center A.

[0032] Figure 4 It is a schematic diagram of the structure of the clamping shaft in Example 1 of the present invention.

[0033] Figure 5 This is a schematic diagram of the structure of the middle pad in Example 1 of the present invention.

[0034] Figure 6 It is a schematic structural diagram of the compression screw sleeve in Example 1 of the present invention.

[0035] Legend: 01, cylinder body; 02, convex edge of cylinder mouth; 1, clamping shaft; 11, connecting shaft; 12, circular groove; 121, external thread; 122, concave annular stop surface; 123, annular end face; 124, grinding wheel cavity; 13, coolant pipeline; 2, middle pad; 21, semicircular arc liner; 211, semicircular arc boss; 212, semicircular arc clamping wall; 3, clamping screw sleeve; 31, threaded sleeve; 311, internal thread; 32, annular limit platform; 33, limit sleeve; 331, threaded hole; 34, wrench hole; 35, tool withdrawal groove; 4, adjusting bolt; 5, tightening nut; 6, annular washer; 7, bolt pad; 8, dividing groove. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0037] Thin-walled tube: When the ratio of outer diameter to inner diameter is less than or equal to 1.2, it is called a thin-walled tube.

[0038] Tool withdrawal groove: In lathe processing, it is convenient to withdraw the tool and process the process to the bottom of the blank, and a pre-made empty groove at the end of the surface to be processed.

[0039] Example 1

[0040] Figure 1 and Figure 2The present invention shows a specific embodiment of the inner hole grinding positioning clamping device of a thin-walled cylindrical part. The thin-walled cylindrical part includes a cylinder 01 and a cylinder mouth convex edge 02. The cylinder mouth convex edge 02 is a convex edge folded outward at the open end of the cylinder 01. The device includes a clamping shaft 1, a middle pad 2, a clamping screw sleeve 3, an adjusting bolt 4 and a tightening nut 5. The clamping shaft 1 includes a connecting shaft 11 and a circular groove 12. One end of the connecting shaft 11 is coaxially connected to the outer bottom surface of the circular groove 12, and the other end is used to connect with the rotating shaft of the machine tool. The circular groove 12 is used to clamp the cylinder 01; the outer circumferential surface of the circular groove 12 is provided with an external thread 121, and the open end of the circular groove 12 includes an inner concave annular stop surface 122 and an outer annular end surface 123, the inner concave annular stop surface 122 is used to abut against the front face of the cylinder mouth with a convex edge, and the inner diameter of the inner concave annular stop surface 122 is greater than or equal to the inner diameter of the cylinder 01; the middle pad 2 includes two semicircular arc pads 21, and the semicircular arc pads 21 include a semicircular end surface 123 located on the inner side. The arc boss 211 and the semicircular arc pressing wall 212 located on the outside, the semicircular arc boss 211 is used to abut against the back of the barrel mouth convex edge 02; the compression screw sleeve 3 includes a threaded sleeve 31, an annular stopper 32 and a stopper sleeve 33 coaxially connected in sequence, the threaded sleeve 31 is provided with an internal thread 311 that cooperates with the external thread 121, the annular stopper 32 is used to abut against the semicircular arc pressing wall 212 to achieve axial compression of the middle pad 2, the middle pad 2 is made of rigid material, the barrel mouth convex edge 02 The sum of the axial dimension of and the axial dimension of the middle pad 2 is greater than the distance between the concave annular stop surface 122 and the annular limit platform 32, so that a gap is left between the annular end surface 123 and the semicircular arc clamping wall 212 as a reserved clamping space; four threaded holes 331 are evenly opened on the circumference of the limit sleeve 33, and the adjusting bolt 4 is used to pass through the threaded hole 331 and then abut against the cylinder 01, and the tightening nut 5 is located on the adjusting bolt 4 to fix the relative position of the adjusting bolt 4 and the limit sleeve 33.

[0041] like Figure 3As shown, in this embodiment, the concave annular stop surface 122 and the semicircular arc boss 211 are clamped from both sides of the barrel mouth convex edge 02 to achieve preliminary axial positioning of the thin-walled barrel 01, and then the compression screw sleeve 3 is screwed on the connection between the circular groove 12, the middle pad 2 and the barrel 01. The compression screw sleeve 3 and the circular groove 12 are screwed in an orderly manner by means of threaded engagement. During the screwing process, the annular limit platform 32 applies thrust to the middle pad 2 from the axial direction, so that the middle pad 2 is further pressed against the barrel mouth convex edge 02 and the open end of the circular groove 12, thereby limiting the axial displacement of the barrel 01. The compression screw sleeve 3 and the circular groove 12 are threadedly matched to press the connection radially and axially, and the pressing force is transmitted to the barrel 01, so that the barrel 01 and the clamping device generate sufficient friction (clamping force) to achieve reliable clamping. On this basis, the barrel 01 is adjusted and tightened by a plurality of adjusting bolts 4 and a tightening nut 5 that are inserted into the compression screw sleeve 3. Furthermore, since the cylinder 01 is positioned and clamped at the open end of the circular groove 12, a grinding wheel cavity 124 is left between the end of the cylinder 01 and the bottom of the circular groove 12 to accommodate the grinding wheel ground to the end of the cylinder 01, and the inner diameter of the concave annular stop surface 122 is greater than or equal to the inner diameter of the cylinder 01, so that the grinding wheel can easily pass through the cylinder 01 to reach the grinding wheel cavity 124, effectively ensuring uniform wear of the grinding wheel, and also ensuring uniform grinding of the inner wall of the thin-walled cylinder.

[0042] Specifically, when grinding thin-walled cylindrical parts, the machine tool rotates around the axis, such as Figure 4 As shown, in this embodiment, the connecting shaft 11 is designed as a cylinder, and the outer wall of the cylinder is the machine tool clamping surface (such as Figure 4 As shown in B), it is convenient to adjust the axis of the clamping shaft 1 to be concentric with the axis of the machine tool. Figure 5 As shown, the middle pad 2 is divided into two semi-circular arc pads 21 by cutting a dividing groove 8 of a certain width along the diameter of a circular part. The width of the dividing groove 8 is 1mm to 2mm, which is convenient for installing and removing the two semi-circular arc pads 21. The end of the adjusting bolt 4 is processed into a flat end surface, which is convenient for applying a certain clamping force to the cylinder 01. The relative radial displacement of the cylinder 01 is adjusted by adjusting the screwing depth of the bolt 4.

[0043] In this embodiment, the connecting shaft 11 is a hollow structure, and the interior serves as a coolant pipeline 13, which is connected to the circular groove 12 through the hollow connecting shaft 11, so that the coolant can enter the grinding space from the machine tool end to cool the grinding process. At the same time, metal chips and coolant can be discharged from the connecting shaft 11 to the waste liquid collection area.

[0044] In this embodiment, the device also includes an annular gasket 6. When in use, the annular gasket 6 is placed between the barrel mouth convex edge 02 and the concave annular stop surface 122. The purpose is to increase the contact area between the parts and increase the friction between the barrel mouth convex edge 02 and the concave annular stop surface 122. At the same time, the annular gasket 6 avoids rigid contact between the two, has a shock-absorbing and buffering effect, and can effectively avoid unnecessary wear on the end face of the barrel 01.

[0045] In this embodiment, the annular gasket 6 is a felt ring. Adding a felt ring between metal parts can increase the contact area between the parts, thereby further increasing the friction. The felt ring has good toughness and elasticity and good wear resistance, and can better ensure the friction and buffering force between the barrel mouth convex edge 02 and the concave annular stop surface 122.

[0046] In this embodiment, the device further includes a bolt pad 7, which is located between the end of the adjusting bolt 4 and the cylinder 01 in the use state. The bolt pad 7 mainly prevents the adjusting bolt 4 from directly contacting the grinding body, increases the contact friction by increasing the contact area, and also protects the surface of the cylinder 01 from damage. Specifically, in this embodiment, the bolt pad 7 is copper, and the thickness of the copper is 0.8 mm.

[0047] like Figure 6 As shown, in this embodiment, the outer periphery of the compression screw sleeve 3 is provided with a wrench hole 34, and the wrench hole 34 is four blind holes arranged along the outer circumference of the compression screw sleeve 3. By inserting a wrench into the wrench hole 34, the compression screw sleeve 3 can be assisted to be tightened or loosened, making clamping and disassembly more labor-saving and convenient.

[0048] In this embodiment, the middle pad 2 is made of aluminum, which is beneficial to protecting thin-walled cylindrical parts and reducing costs.

[0049] In this embodiment, the length of the internal thread 311 in the compression screw sleeve 3 needs to be set greater than the length of the external thread 121 of the clamping shaft 1. Due to the presence of the middle pad 2, the above setting can ensure that the effective connection length of the internal and external threads is long enough, thereby ensuring the reliability of the connection.

[0050] In this embodiment, the ratio of the outer diameter to the inner diameter of the cylinder 01 is less than or equal to 1.2.

[0051] In this embodiment, a tool-retracting groove 35 is further provided in the compression screw sleeve 3 . The tool-retracting groove 35 is located between the threaded sleeve 31 and the annular limiting platform 32 . The tool-retracting groove 35 facilitates the processing and forming of the internal thread 311 .

[0052] Example 2

[0053] A method for using the thin-walled cylindrical part inner hole grinding positioning clamping device based on Example 1 comprises the following steps:

[0054] S1, clamp the clamp shaft 1 on the machine tool shaft through the connecting shaft 11, and adjust the position so that the clamp shaft 1 is concentric with the machine tool shaft;

[0055] S2. Extend one end of the barrel 01 with the convex edge into the circular groove 12, so that the end surface of the barrel mouth with the convex edge is in close contact with the concave annular stop surface 122, so as to preliminarily realize the axial (Z direction) positioning of the barrel 01. The other end of the barrel 01 is placed on the machine tool holder and kept horizontally.

[0056] S3, put two semicircular arc gaskets 21 on the outside of the cylinder 01 from both sides, so that the semicircular arc boss 211 extends along the outer wall of the cylinder 01 to the back side of the cylinder mouth convex edge 02, and manually press inwards;

[0057] S4, pass the compression screw sleeve 3 through the cylinder 01, screw it onto the external thread 121 of the clamping shaft 1, and tighten it manually first. At this time, there is a gap between the annular end face 123 and the semicircular arc compression wall 212 as a reserved compression space, and then pre-tighten it with a wrench until the annular limit platform 32 abuts against the semicircular arc compression wall 212, so that the cylinder 01 has no free movement, thereby realizing the axial (Z direction) positioning of the cylinder 01;

[0058] S5, screw the tightening nut 5 onto the adjusting bolt 4, and screw the adjusting bolt 4 with the tightening nut 5 into the threaded hole 331, so that the end of the adjusting bolt 4 is in close contact with the outer wall of the cylinder 01;

[0059] S6. Start the machine tool and rotate it slowly. Use the dial gauge to measure the runout of the outer circumference of the cylinder 01. According to the runout detected initially, adjust the relative positions of the four adjusting bolts 4 and the limit sleeve 33 to keep the cylinder 01 and the machine tool concentric and realize radial (X and Y direction) positioning. After the adjustment is completed, tighten the tightening nut 5 to prevent the adjusting bolt 4 from loosening.

[0060] S7. Tighten the clamping nut 3 again to complete the clamping.

[0061] Thin-walled cylindrical parts need to rotate with the machine tool chuck and not slide to meet the grinding requirements. To achieve this effect, the thin-walled cylindrical parts must be subjected to sufficient friction, and the friction is generated by the pressure of the external force on the thin-walled cylinder. When the input pressure is constant, increasing the number of force points can increase the friction of the thin-walled cylindrical parts. When the force points are increased from a single point to a surface, the friction of the thin-walled cylindrical parts is also large enough to rotate with the machine tool chuck and not slide.

[0062] In order to avoid harmful deformation of the thin-walled outer cylinder caused by sufficiently large pressure, the clamping method of this embodiment converts the pressure direction from radial to axial. First, axial positioning is performed through the cooperation of the middle pad 2, the open end of the circular groove 12 and the clamping screw sleeve 3 to achieve preliminary fixation of the thin-walled cylindrical part. Then, fine adjustment is made by screwing the adjusting bolt 4 in and out to achieve sliding adjustment and centering on the radial two-dimensional plane, thereby improving the clamping accuracy of the thin-walled cylindrical part. Finally, it is tightened with the tightening nut 5. This can provide sufficient friction for the rotation of the thin-walled cylindrical part, meet the firmness of the clamping, achieve the accuracy requirement of grinding positioning, and protect the thin-walled cylindrical part from deformation or even scrapping due to uneven force.

[0063] Furthermore, in step S2 of this embodiment, before extending the end of the cylinder 01 with the convex edge into the circular groove 12, a felt ring is first installed on the concave annular stop surface 122 of the circular groove 12 to increase the friction and buffering force between the end face with the convex edge of the cylinder mouth and the concave annular stop surface 122.

[0064] Furthermore, in step S5 of this embodiment, a small piece of copper sheet is installed at the place where the adjusting bolt 4 contacts the outer wall of the cylinder 01, and the adjusting bolt 4 is tightened so that the copper sheet cannot move freely, so as to further increase the contact area between the end of the adjusting bolt 4 and the cylinder 01, increase friction, and reduce the single-point force pressure on the cylinder wall.

[0065] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any technician familiar with the art can use the above disclosed methods and technical contents to make many possible changes and modifications to the technical solutions of the present invention without departing from the spirit and technical solutions of the present invention, or modify them into equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solutions of the present invention still fall within the scope of protection of the technical solutions of the present invention.

Claims

1. A thin-walled cylindrical part inner hole grinding positioning clamping device, the thin-walled cylindrical part comprises a cylinder (01) and a cylinder mouth convex edge (02), the cylinder mouth convex edge (02) is a convex edge located at the opening end of the cylinder (01) and folded outward, characterized in that: The device comprises a clamping shaft (1), a middle pad (2), a pressing screw sleeve (3), an adjusting bolt (4) and a tightening nut (5); the clamping shaft (1) comprises a connecting shaft (11) and a circular groove (12); one end of the connecting shaft (11) is coaxially connected to the outer bottom surface of the circular groove (12), and the other end is used to be connected to the rotating shaft of a machine tool; the circular groove (12) is used to clamp the cylinder (01); An external thread (121) is provided on the outer peripheral surface of the circular groove (12); the open end of the circular groove (12) comprises an inner concave annular stop surface (122) located on the inner side and an annular end surface (123) located on the outer side; the inner concave annular stop surface (122) is used to abut against the front side of the barrel mouth with a convex edge; the inner diameter of the inner concave annular stop surface (122) is greater than or equal to the inner diameter of the barrel body (01); The middle pad (2) comprises two semicircular arc pads (21), the semicircular arc pads (21) comprising a semicircular arc boss (211) located on the inner side and a semicircular arc pressing wall (212) located on the outer side, the semicircular arc boss (211) being used to abut against the back side of the barrel mouth convex edge (02); The compression screw sleeve (3) comprises a threaded sleeve (31), an annular limiting platform (32) and a limiting sleeve (33) which are coaxially connected in sequence, and an internal thread (311) which cooperates with the external thread (121) is provided in the threaded sleeve (31); the annular limiting platform (32) is used to abut against the semicircular arc compression wall (212) to achieve axial compression of the middle pad (2); the middle pad (2) is made of rigid material, and the sum of the axial dimensions of the barrel mouth convex edge (02) and the axial dimensions of the middle pad (2) is greater than the inner concave annular The distance between the stop surface (122) and the annular limiting platform (32) is such that a gap is left between the annular end surface (123) and the semicircular arc clamping wall (212) as a reserved clamping space; a plurality of threaded holes (331) are evenly arranged on the circumference of the limiting sleeve (33); the adjusting bolt (4) is used to pass through the threaded hole (331) and then abut against the cylinder (01); the tightening nut (5) is located on the adjusting bolt (4) and is used to fix the relative position of the adjusting bolt (4) and the limiting sleeve (33).

2. The thin-walled cylindrical part inner hole grinding positioning clamping device according to claim 1 is characterized in that: The connecting shaft (11) is a hollow structure, and the interior of the connecting shaft (11) is connected to the circular groove (12) to achieve the delivery of coolant and the discharge of grinding chips.

3. The thin-walled cylindrical part inner hole grinding positioning clamping device according to claim 1 is characterized in that: The device also includes an annular gasket (6) which is used to increase the friction between the barrel mouth convex edge (02) and the concave annular stop surface (122).

4. The thin-walled cylindrical part inner hole grinding positioning clamping device according to claim 3 is characterized in that: The annular gasket (6) is a felt ring.

5. The thin-walled cylindrical part inner hole grinding positioning clamping device according to claim 1 is characterized in that: The device further comprises a bolt washer (7), and in a state of use, the bolt washer (7) is located between the end of the adjusting bolt (4) and the cylinder (01).

6. The thin-walled cylindrical part inner hole grinding positioning clamping device according to claim 5 is characterized in that: The bolt pad (7) is made of copper sheet, and the thickness of the copper sheet is 0.5 mm to 0.8 mm.

7. The thin-walled cylindrical part inner hole grinding positioning clamping device according to claim 1 is characterized in that: The outer periphery of the compression screw sleeve (3) is provided with a wrench hole (34).

8. The thin-walled cylindrical part inner hole grinding positioning clamping device according to claim 1 is characterized in that: The middle pad (2) is made of aluminum.

9. The thin-walled cylindrical part inner hole grinding positioning clamping device according to any one of claims 1 to 8, characterized in that: The ratio of the outer diameter to the inner diameter of the cylinder (01) is less than or equal to 1.

2.

10. A clamping method for the inner hole grinding positioning clamping device of a thin-walled cylindrical part according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Clamp the clamping shaft (1) onto the rotating shaft of the machine tool via the connecting shaft (11), and adjust the position so that the clamping shaft (1) is concentric with the rotating shaft of the machine tool; S2. Extend one end of the barrel (01) with the convex edge into the circular groove (12), so that the end surface with the convex edge of the barrel mouth is in close contact with the concave annular stop surface (122), so as to preliminarily achieve the axial positioning of the barrel (01), and the other end of the barrel (01) is placed on the machine tool holder and kept horizontally; S3, insert two semicircular arc gaskets (21) onto the outside of the cylinder (01) from both sides, so that the semicircular arc boss (211) extends along the outer wall of the cylinder (01) to the back side of the cylinder mouth convex edge (02), and manually press inwards; S4, pass the compression screw sleeve (3) through the cylinder (01), screw it onto the external thread (121) of the clamping shaft (1), and tighten it initially until the annular stopper (32) abuts against the semicircular compression wall (212), thereby achieving axial positioning of the cylinder (01); S5. Screw the tightening nut (5) onto the adjusting bolt (4), and screw the adjusting bolt (4) with the tightening nut (5) into the threaded hole (331), so that the end of the adjusting bolt (4) is in close contact with the outer wall of the cylinder (01); S6, start the machine tool to rotate slowly, measure the runout of the outer circumference of the cylinder (01), and adjust the relative positions of the plurality of adjusting bolts (4) and the limiting sleeve (33) according to the runout detected initially to achieve concentricity between the cylinder (01) and the machine tool and radial positioning. After the adjustment is completed, tighten the tightening nut (5) to prevent the adjusting bolt (4) from loosening; S7. Tighten the compression nut (3) again to complete the clamping.

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