Hole connecting surface rolling device and rolling method

Abstract

The application relates to the technical field of part machining, in particular to a connecting hole surface rolling device and a rolling method. The connecting hole surface rolling device comprises a mandrel, a sleeve and a plurality of rolling balls, the sleeve is sleeved on the mandrel, and the plurality of rolling balls are uniformly and intervally arranged on the sleeve. The mandrel can move along the axial direction and rotate along the circumferential direction, the mandrel has an equal-diameter section, a variable-diameter section and a limiting ring which are sequentially connected from top to bottom, the cross-sectional area of the variable-diameter section gradually increases from top to bottom, the sleeve can move on the equal-diameter section and the variable-diameter section, and the limiting ring limits the sleeve from separating from one end of the variable-diameter section away from the equal-diameter section. The sleeve penetrates the connecting hole of a workpiece from top to bottom, the workpiece drives the sleeve to move to the equal-diameter section, so that the rolling balls roll against the hole wall of the connecting hole. The sleeve penetrates the connecting hole from bottom to top, the workpiece drives the sleeve to move to the variable-diameter section, so that the outer circumferential surface of the mandrel forces the rolling balls to press against the hole wall of the connecting hole, and the rolling pressure of the rolling balls against the hole wall of the connecting hole gradually increases from top to bottom.

Description

Technical Field

[0001] This invention relates to the field of parts processing technology, and in particular to a rolling device and rolling method for connecting hole surfaces. Background Technology

[0002] Aircraft structural connections primarily utilize mechanical fasteners such as bolts and rivets, resulting in a large number, variety, and wide distribution of fastener connection holes within aircraft. Due to stress concentration at the hole edges, connection holes are often weak points in aerospace components. Statistics show that over 80% of aerospace structural component fractures are caused by fatigue failure around connection holes.

[0003] Therefore, there is an urgent need to design a rolling device and rolling method for the surface of the connecting hole to solve the above technical problems. Summary of the Invention

[0004] One object of the present invention is to provide a surface rolling device for connecting holes, which can improve the hole wall strengthening effect and workpiece service performance.

[0005] To achieve this objective, the present invention adopts the following technical solution: A device for rolling the surface of a connecting hole is provided, characterized in that it includes: a rolling mechanism, the rolling mechanism including a mandrel, a sleeve and a plurality of balls, the sleeve being sleeved on the mandrel, and the plurality of balls being rolled evenly and at intervals on the sleeve; The mandrel is capable of moving along its own axis and rotating around its own circumference. The mandrel has a constant diameter section, a variable diameter section, and a limiting ring connected sequentially from top to bottom. The cross-sectional area of ​​the constant diameter section in its own axis is less than or equal to the cross-sectional area of ​​the variable diameter section. The cross-sectional area of ​​the variable diameter section gradually increases from top to bottom. The sleeve is capable of moving between the constant diameter section and the variable diameter section. The limiting ring restricts the sleeve from detaching from the end of the variable diameter section away from the constant diameter section. The sleeve passes through the connecting hole of the workpiece from top to bottom. The workpiece pushes the sleeve to the equal diameter section so that the ball rolls against the hole wall of the connecting hole. The sleeve passes through the connecting hole from bottom to top. The workpiece pushes the sleeve to the variable diameter section so that the outer circumferential surface of the mandrel forces the ball to press against the hole wall of the connecting hole, and the rolling force of the ball against the hole wall of the connecting hole gradually increases from top to bottom.

[0006] Optionally, the outer periphery of the sleeve is provided with ball bearing holes, the ball bearing holes including multiple rows of ball bearing holes evenly spaced along the axial direction of the sleeve, and each row of ball bearing holes including multiple ball bearing holes evenly spaced along the circumferential direction of the sleeve, with one ball bearing rolling in one ball bearing hole.

[0007] Optionally, the connecting hole surface rolling device further includes a power mechanism, the output end of which is connected to the mandrel, and the power mechanism is used to drive the mandrel to move along its own axis and rotate along its own circumference.

[0008] Optionally, the power mechanism includes a driving member and a transmission rod. One end of the transmission rod is connected to the driving member, and the other end of the transmission rod is connected to the equal-diameter section. A stepped surface is formed between the transmission rod and the equal-diameter section. The sleeve can move to the equal-diameter section and abut against the stepped surface. The driving member is used to drive the transmission rod to move the mandrel.

[0009] Optionally, the connecting hole surface rolling device further includes a fixing mechanism and a supporting mechanism. The workpiece is fixed below the fixing mechanism, and the supporting mechanism is fixed above the fixing mechanism. The supporting mechanism has a mounting cavity and a through hole communicating with the mounting cavity. The power mechanism is fixed in the mounting cavity. A first hole is provided on the fixing mechanism, and the rolling mechanism passes through the first hole and the through hole and is connected to the output end of the power mechanism.

[0010] Optionally, the fixing mechanism includes a guide and a template, the workpiece is detachably disposed below the template, and the support mechanism is detachably disposed above the guide; The guide member has a through hole, and a guide protrusion protrudes from the outer periphery of the first hole toward the template. The template has a second hole, and the guide protrusion passes through the second hole. The diameter of the first hole and the connecting hole is d, and the coaxiality deviation between the second hole and the connecting hole is less than or equal to 0.001d.

[0011] Optionally, a positioning pin is provided on the template, and a positioning hole is provided on the guide, with the upper end of the positioning pin inserted into the positioning hole.

[0012] Optionally, the template is provided with a first mounting hole, the workpiece is provided with a first fixing hole, and the connecting hole surface rolling device further includes a first fastener, which passes through the first mounting hole and is threaded into the first fixing hole; The support mechanism is provided with a second mounting hole, the guide is provided with a second fixing hole, and the connecting hole surface rolling device further includes a second fastener, which passes through the second mounting hole and is threaded into the second fixing hole.

[0013] Optionally, the support mechanism includes a housing and a base plate. The housing covers the base plate to form the mounting cavity. The base plate is provided with the through hole. The base plate is fixed above the fixing mechanism.

[0014] Another objective of this invention is to provide a rolling method that can improve the wall strengthening effect of connecting holes and the service performance of workpieces.

[0015] To achieve this objective, the present invention adopts the following technical solution: A rolling method is provided, applied to the aforementioned rolling device for the surface of connecting holes, comprising the following steps: S1: Move the mandrel so that it passes through the connecting hole on the workpiece from top to bottom, ensuring that the entire sleeve and the multiple rows of balls mounted thereon pass through the connecting hole; S2: The mandrel is rotated and pulled back, so that the sleeve approaches the lower surface of the connecting hole of the workpiece from bottom to top. When the first row of balls contacts the connecting hole, the bottom end face of the sleeve will be in close contact with the top surface of the limiting ring of the mandrel. The outer circumference of the variable diameter section will force the multiple rows of balls to form rolling reinforcement with the interference amount gradually increasing from top to bottom.

[0016] The beneficial effects of the present invention include at least the following: This invention provides a surface rolling device for connecting holes, including a rolling mechanism comprising a mandrel, a sleeve, and multiple balls. The sleeve is fitted onto the mandrel, and the multiple balls are evenly spaced and rolled on the sleeve. The mandrel is axially movable and circumferentially rotatable. The mandrel has a constant-diameter section, a variable-diameter section, and a limiting ring connected sequentially from top to bottom. The cross-sectional area of ​​the constant-diameter section in its axial direction is less than or equal to the cross-sectional area of ​​the variable-diameter section, and the cross-sectional area of ​​the variable-diameter section gradually increases from top to bottom. The sleeve is movable between the constant-diameter section and the variable-diameter section, and the limiting ring restricts the sleeve from detaching from the end of the variable-diameter section away from the constant-diameter section. The sleeve passes through the connecting hole of the workpiece from top to bottom. The workpiece pushes the sleeve to the constant-diameter section, causing the balls to roll and abut against the hole wall. The sleeve passes through the connecting hole from bottom to top. The workpiece pushes the sleeve to the variable-diameter section, causing the outer circumferential surface of the mandrel to force the balls to press against the hole wall, and the rolling force of the balls against the hole wall gradually increases from top to bottom.

[0017] The sleeve is slidably mounted on the mandrel. When the workpiece is fixed, the sleeve passes downwards through the connecting hole of the workpiece from above. The wall of the connecting hole contacts the balls on the sleeve. The resistance force exerted by the hole wall on the balls tends to cause the balls to move towards the mandrel. However, the sleeve is located in the variable diameter section. Because the outer diameter of the variable diameter section is larger, there is no space for movement between the balls and the mandrel. Therefore, the interaction force between the balls and the hole wall causes the sleeve to move upwards to the constant diameter section with a smaller outer diameter. When the sleeve is located in the constant diameter section, because the outer diameter of the constant diameter section is smaller, the resistance force exerted by the hole wall on the balls causes the balls to move towards the mandrel. The balls do not exert pressure on the hole wall; the balls and the hole wall only have rolling contact. When the mandrel is rotated back, the sleeve rotates upwards through the connecting hole of the workpiece. The hole wall then contacts the balls on the sleeve. The resistance force exerted by the hole wall on the balls causes them to move towards the mandrel. However, the sleeve is located in the variable diameter section. Because the outer diameter of the variable diameter section is larger, there is no space for movement between the balls and the mandrel. Furthermore, the sleeve is clamped between the workpiece and the limiting ring and cannot move to the smaller, equal-diameter section. Therefore, both the mandrel and the hole wall exert mutual forces through the balls, thus achieving rolling reinforcement of the hole wall. Secondly, because the cross-sectional area of ​​the variable diameter section gradually increases from top to bottom, the rolling force exerted by the balls on the hole wall at the same position gradually increases as the sleeve passes through the connecting hole from bottom to top. This achieves a progressively increasing and cumulative rolling reinforcement effect, improving the fatigue resistance of the connecting hole. Compared with the traditional push-out hole surface rolling technology, the connecting hole surface rolling device provided in this embodiment adopts a pull-back rolling operation method. This makes the hole edge protrusion caused by the plastic flow of the material appear at the outlet end (tool side) of the connecting hole after the surface rolling strengthening treatment, rather than at the inlet end. This makes it easier to remove the protrusion through post-processing such as end face grinding and polishing. This has a particularly outstanding beneficial effect on the strengthening of connecting holes in closed structures such as boxes and enclosures. In these closed structures, the hole edge protrusion caused by the plastic flow of the material in the traditional push-out hole surface rolling technology appears at the inlet end of the connecting hole (inside the closed structure), making the removal of the protrusion structure more complicated and cumbersome, requiring a special scraping tool to complete.

[0018] This invention provides a continuous rolling method applied to the aforementioned rolling device for connecting hole surfaces, comprising the following steps: S1: Moving the mandrel so that it passes through the connecting hole on the workpiece from top to bottom, ensuring that the entire sleeve and the multiple rows of balls mounted thereon pass through the connecting hole; S2: Rotating the mandrel back so that the sleeve approaches the lower surface of the connecting hole on the workpiece from bottom to top. When the first row of balls contacts the connecting hole, the bottom end face of the sleeve will be in close contact with the top surface of the mandrel's limiting ring, and the outer circumferential surface of the variable diameter section will force the multiple rows of balls to form a rolling reinforcement with progressively increasing interference from top to bottom. This rolling method can improve the hole wall reinforcement effect of the connecting hole and the service performance of the workpiece. Attached Figure Description

[0019] Figure 1 This is a partial cross-sectional view of the connecting hole surface rolling device provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the connecting hole surface rolling device provided in an embodiment of the present invention; Figure 3 This is a partial structural schematic diagram of the connecting hole surface rolling device provided in an embodiment of the present invention; Figure 4 This is an assembly diagram of the rolling mechanism and the power mechanism provided in the embodiment of the present invention; Figure 5 This is an exploded structural diagram of the rolling mechanism and the power mechanism provided in the embodiment of the present invention; Figure 6 This is a comparison chart of the fatigue DFR values ​​of the center single opening of the connecting hole provided in the embodiment of the present invention.

[0020] Figure Labels 1. Rolling mechanism; 11. Mandrel; 111. Equal diameter section; 112. Variable diameter section; 113. Limiting ring; 12. Sleeve; 13. Ball bearings; 2. Fixing mechanism; 21. Guide component; 211. Guide protrusion; 2111. First hole; 22. Template; 221. Positioning pin; 3. Power mechanism; 31. Driving component; 32. Transmission rod; 4. Supporting mechanism; 41. Outer shell; 42. Base plate; 421. Through hole; 5. First fastener; 6. Second fastener; 100, workpiece; 1001, connecting hole. Detailed Implementation

[0021] To make the technical problems solved by this invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of this invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to this invention are shown in the accompanying drawings, not all of them.

[0022] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0024] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0025] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] like Figures 1 to 5 As shown, this embodiment provides a surface rolling device for connecting holes, including a rolling mechanism 1. The rolling mechanism 1 includes a mandrel 11, a sleeve 12, and a plurality of balls 13. The sleeve 12 is sleeved on the mandrel 11, and the plurality of balls 13 are evenly spaced and rolled on the sleeve 12. The mandrel 11 can move along its own axial direction and rotate along its own circumference. The mandrel 11 has a constant diameter section 111, a variable diameter section 112, and a limiting ring 113 connected sequentially from top to bottom. The cross-sectional area of ​​the constant diameter section 111 in its own axial direction is less than or equal to the cross-sectional area of ​​the variable diameter section 112. The cross-sectional area of ​​the variable diameter section 112 gradually increases from top to bottom. The sleeve 12 can move between the constant diameter section 111 and the variable diameter section 112. The limiting ring 113 restricts the sleeve 12 from disengaging from the end of the variable diameter section 112 away from the constant diameter section 111. The sleeve 12 passes through the connecting hole 1001 of the workpiece 100 from top to bottom. The workpiece 100 pushes the sleeve 12 to the equal diameter section 111, so that the ball 13 rolls against the hole wall of the connecting hole 1001. The sleeve 12 passes through the connecting hole 1001 from bottom to top. The workpiece 100 pushes the sleeve 12 to the variable diameter section 112, so that the outer circumferential surface of the mandrel 11 forces the ball 13 to press against the hole wall of the connecting hole 1001, and the rolling force of the ball 13 against the hole wall of the connecting hole 1001 gradually increases from top to bottom.

[0027] like Figure 2 and Figure 3As shown, the sleeve 12 is a cylindrical structure, and multiple balls 13 are rolled on the cylindrical wall. In a specific implementation, the cylindrical structure can be provided with an inner cylinder and an outer cylinder that are coaxially sleeved. Corresponding ball holes are provided on the inner cylinder and the outer cylinder, and the balls 13 are rolled between the inner cylinder and the outer cylinder so that the balls 13 roll in the ball holes and will not fall out. The sleeve 12 is slidably mounted on the mandrel 11. After the workpiece 100 is fixed, the sleeve 12 passes downward through the connecting hole 1001 of the workpiece 100 from above. The wall of the connecting hole 1001 then contacts the ball bearing 13 on the sleeve 12. The pressure exerted by the hole wall on the ball bearing 13 will cause the ball bearing 13 to tend to move towards the mandrel 11. However, the sleeve 12 is located in the variable diameter section 112. Because the outer diameter of the variable diameter section 112 is larger, there is no space for movement between the ball bearing 13 and the mandrel 11. Therefore, the interaction force between the ball bearing 13 and the hole wall will cause the sleeve 12 to move upward to the equal diameter section 111 with a smaller outer diameter. The sleeve 12 is located in the equal diameter section 111. Because the outer diameter of the equal diameter section 111 is smaller, the pressure exerted by the hole wall on the ball bearing 13 will cause the ball bearing 13 to move towards the mandrel 11. The ball bearing 13 will not exert pressure on the hole wall; the ball bearing 13 and the hole wall will only have rolling contact. When the mandrel 11 is rotated back, the sleeve 12 will rotate from the bottom of the workpiece 100 and pass through the connecting hole 1001 of the workpiece 100. The wall of the connecting hole 1001 will then contact the ball 13 on the sleeve 12. The pressure applied by the wall of the hole to the ball 13 will cause the ball 13 to move toward the mandrel 11. However, the sleeve 12 is located in the variable diameter section 112. Because the outer diameter of the variable diameter section 112 is larger, there is no space for movement between the ball 13 and the mandrel 11. Furthermore, the sleeve 12 is sandwiched between the workpiece 100 and the limiting ring 113 and cannot move to the equal diameter section 111 with a smaller outer diameter. Thus, the mandrel 11 and the hole wall both exert mutual forces through the ball 13, thereby achieving rolling reinforcement of the hole wall. Secondly, since the cross-sectional area of ​​the variable diameter section 112 gradually increases from top to bottom, when the sleeve 12 passes through the connecting hole 1001 from bottom to top, the rolling pressure applied by the ball 13 to the same position of the hole wall also gradually increases, thereby achieving a progressively increasing and cumulative rolling reinforcement effect, which can improve the fatigue resistance of the connecting hole 1001.

[0028] Compared to traditional push-out hole surface rolling technology, the hole surface rolling strengthening device provided in this embodiment can achieve a larger cumulative interference in the connecting hole 1001 through the progressively increasing interference of the balls 13. This results in higher amplitude and greater infiltration of residual compressive stress and processing strengthening on the surface of the connecting hole 1001, thereby significantly improving the fatigue resistance of the connecting hole 1001. Figure 6As shown, workpiece 100 was tested. The workpiece 100 has a thickness of 10mm and is made of 7050-T7451 aluminum alloy sheet. The connecting hole 1001 that needs to be strengthened is a single central opening with an inner diameter of 9.5mm. The test results show that the fatigue DFR value of the unstrengthened connecting hole 1001 is 116MPa. The fatigue DFR value of the connected hole 1001 strengthened using the traditional push-out hole surface rolling technology is 129MPa, an improvement of 11.2%. The fatigue DFR value of the connected hole 1001 strengthened using the connecting hole surface rolling device provided in this solution is 141MPa, an improvement of 21.6%.

[0029] Compared with the traditional push-out hole surface rolling technology, the connecting hole surface rolling device provided in this embodiment adopts a pull-back rolling operation method. After the connecting hole 1001 is surface rolled and strengthened, the hole edge protrusion caused by the plastic flow of the material appears at the outlet end (tool side) of the connecting hole 1001, rather than the inlet end. This makes it easier to remove the protrusion through post-processing such as end face grinding and polishing. This has a very significant beneficial effect on strengthening the connecting hole 1001 on closed structures such as boxes and enclosures. In such closed structures, the hole edge protrusion caused by the plastic flow of the material in the traditional push-out hole surface rolling technology appears at the inlet end (inside the closed structure) of the connecting hole 1001, making the removal of the protrusion structure more complicated and cumbersome, requiring a special scraping tool to complete.

[0030] Optionally, such as Figure 4 As shown, the outer periphery of the sleeve 12 is provided with ball bearing holes. These ball bearing holes include multiple rows of ball bearing holes evenly spaced along the axial direction of the sleeve 12, and each row includes multiple ball bearing holes evenly spaced along the circumferential direction of the sleeve 12. One ball 13 rolls within each ball bearing hole. The evenly spaced ball bearing holes provide uniform rolling pressure to the wall of the connecting hole 1001 while the mandrel 11 moves along its axial direction and rotates along its circumferential direction, ensuring consistent rolling reinforcement effect across the hole wall. In this embodiment, the multiple ball bearing holes are distributed in multiple rows parallel to the axial direction of the sleeve 12, and multiple columns parallel to the circumferential direction of the sleeve 12. In other embodiments, the multiple rows of ball bearing holes may also be spirally distributed on the sleeve 12.

[0031] Optionally, such as Figure 3 As shown, the surface rolling device for the connecting hole also includes a power mechanism 3. The output end of the power mechanism 3 is connected to the mandrel 11. The power mechanism 3 is used to drive the mandrel 11 to move along its own axis and rotate along its own circumference. The power mechanism 3 can be a stroke-rotation composite hydraulic cylinder. By connecting the end of the mandrel 11 away from the limiting ring 113 to the piston rod of the hydraulic cylinder, the rotation and extension can be integrated. This type of hydraulic cylinder is existing technology and will not be described in detail here.

[0032] Optionally, such as Figure 3 As shown, the power mechanism 3 includes a drive member 31 and a transmission rod 32. One end of the transmission rod 32 is connected to the drive member 31, and the other end of the transmission rod 32 is connected to the equal diameter section 111. A stepped surface is formed between the transmission rod 32 and the equal diameter section 111. The sleeve 12 can move to the equal diameter section 111 and abut against the stepped surface. The drive member 31 is used to drive the transmission rod 32 to move the mandrel 11.

[0033] The sleeve 12 is slidably mounted on the mandrel 11. When the sleeve 12 is passed downward through the connecting hole 1001 of the workpiece 100 from above, the interaction force between the ball bearing 13 and the hole wall causes the sleeve 12 to move upward to the equal-diameter section 111. Since the outer diameter of the transmission rod 32 is larger than the outer diameter of the equal-diameter section 111, the sleeve 12 will abut against the stepped surface when it moves to the end of the equal-diameter section 111 away from the variable-diameter section 112, thus restricting the sleeve 12 from moving further upward. The axial length of the equal-diameter section 111 in the mandrel 11 is not less than the length of the sleeve 12, so that when the sleeve 12 is passed downward through the connecting hole 1001 from above the workpiece 100, the sleeve 12 can move completely to the equal-diameter section 111.

[0034] Optionally, such as Figure 2 and Figure 3 As shown, the surface rolling device for connecting holes also includes a fixing mechanism 2 and a supporting mechanism 4. The workpiece 100 is fixed below the fixing mechanism 2, and the supporting mechanism 4 is fixed above the fixing mechanism 2. The supporting mechanism 4 has a mounting cavity and a through hole 421 communicating with the mounting cavity. The power mechanism 3 is fixed inside the mounting cavity. A first hole 2111 is provided on the fixing mechanism 2. The rolling mechanism 1 passes through the first hole 2111 and the through hole 421 and connects to the output end of the power mechanism 3. In specific implementation, the workpiece 100 is first fixed below the fixing mechanism 2, the power mechanism 3 is located inside the mounting cavity and connected to the cavity wall of the mounting cavity through a connector, and then the supporting mechanism 4 is fixed above the fixing mechanism 2. Thus, the power mechanism 3, the supporting mechanism 4, the fixing mechanism 2, and the workpiece 100 become a whole. The power mechanism 3 is located inside the mounting cavity, which can also isolate it from the outside, ensuring the safety of the device during use.

[0035] Optionally, such as Figure 1 As shown, the support mechanism 4 includes a housing 41 and a base plate 42. The housing 41 covers the base plate 42 to form a mounting cavity. The base plate 42 has a through hole 421 and is fixed above the fixing mechanism 2. In a specific implementation, the power mechanism 3 is first located inside the housing 41 and connected to the housing 41 through a connector. Then, the base plate 42 is placed at the opening of the housing 41. The through hole 421 on the base plate 42 is used to pass through the mandrel 11.

[0036] Optionally, such as Figure 1 and Figure 3As shown, the fixing mechanism 2 includes a guide member 21 and a template 22. The workpiece 100 is detachably mounted below the template 22, and the support mechanism 4 is detachably mounted above the guide member 21. A first hole 2111 is provided through the guide member 21, and a guide protrusion 211 protrudes from the outer periphery of the first hole 2111 towards the template 22. A second hole is provided on the template 22, and the guide protrusion 211 passes through the second hole. The diameters of the first hole 2111 and the connecting hole 1001 are both d, and the coaxiality deviation between the second hole and the connecting hole 1001 is less than or equal to 0.001d. To ensure the coaxiality of the connecting hole 1001 of the workpiece 100 and the sleeve 12 of the rolling mechanism 1 after overall assembly, it is necessary to ensure that the first hole 2111 of the fixing mechanism 2 connected to the rolling mechanism 1 is coaxial with the connecting hole 1001 of the workpiece 100. The guide member 21 is inserted into the second hole through the guide protrusion 211, thereby limiting the coaxiality deviation between the second hole and the connecting hole 1001 to ensure the coaxial accuracy of the above-mentioned fit. In specific implementation, multiple second holes can be provided on the template 22, and the guide member 21 is inserted into one second hole at a time through the guide protrusion 211 to complete the rolling reinforcement of the connecting hole 1001 of the workpiece 100 that is coaxial with the second hole. Then, the guide member 21 is inserted into another second hole through the guide protrusion 211 to complete the rolling reinforcement of the connecting hole 1001 of the workpiece 100 that is coaxial with the second hole.

[0037] Optionally, such as Figure 1 As shown, a positioning pin 221 is provided on the template 22, and a positioning hole is provided on the guide member 21. The upper end of the positioning pin 221 is inserted into the positioning hole. The positioning pin 221 is used to further limit and fix the relative position of the guide member 21 and the template 22, so as to realize the quick assembly of the template 22 and the guide member 21. Multiple sets of positioning pins 221 are provided, and one set of positioning pins 221 is provided on the outer periphery of a second hole, so that when the guide member 21 is assembled with any set of positioning pins 221, the guide protrusion 211 can be inserted into the corresponding second hole.

[0038] Optionally, such as Figure 1 As shown, a first mounting hole is provided on the template 22, and a second fixing hole is provided on the workpiece 100. The surface rolling device for the connecting hole also includes a first fastener 5, which passes through the first mounting hole and is threaded into the first fixing hole. In specific implementation, a suitable template 22 is selected according to the size of the workpiece 100. According to the specific size of the template 22 and the position of the first mounting hole, the first fixing hole is drilled on the workpiece 100. According to the specifications of the first fastener 5 required to fix the template 22, the first fastener 5 is tapped in the first fixing hole, and then the first fastener 5 is threaded into the first fixing hole through the first mounting hole. The cross-sectional area of ​​the guide member 21 in the axial direction of the mandrel 11 is smaller than the cross-sectional area of ​​the template 22, thereby avoiding the first fastener 5 fixed on the template 22, and allowing the guide member 21 to be fixed on the template 22 at multiple different second holes.

[0039] Optionally, such as Figure 1 As shown, the support mechanism 4 is provided with a second mounting hole, and the guide member 21 is provided with a second fixing hole. The surface rolling device for the connecting hole also includes a second fastener 6, which passes through the second mounting hole and is threaded into the second fixing hole. That is, the guide member 21 is provided with a positioning hole on the side facing the template 22, and a second fixing hole is provided on the side facing the support mechanism 4. The positioning hole and the second fixing hole are axially misaligned in the mandrel 11 to ensure the strength of the guide member 21. In specific assembly, the base plate 42 and the guide member 21 can be fixed first with the second fastener 6, and then the outer shell 41 can be fixed with the base plate 42. The template 22 and the workpiece 100 can be fixed with the first fastener 5. Finally, the guide member 21 is placed on the template 22, and the two are fixed in the radial position of the mandrel 11 by the positioning pin 221 and the guide protrusion 211.

[0040] This embodiment also provides a rolling method applied to the above-mentioned rolling device for connecting hole surfaces, comprising the following steps: S1: Move the mandrel 11 so that the mandrel 11 passes through the connection hole 1001 on the workpiece 100 from top to bottom, ensuring that the entire sleeve 12 and the multiple rows of balls 13 installed on it pass through the connection hole 1001. S2: Rotate the mandrel 11 back, so that the sleeve 12 approaches the lower surface of the connection hole 1001 of the workpiece 100 from bottom to top. When the first row of balls 13 contacts the connection hole 1001, the bottom end face of the sleeve 12 will be in close contact with the top surface of the limiting ring 113 of the mandrel 11. The outer circumference of the variable diameter section 112 will force the multiple rows of balls 13 to form rolling reinforcement with the interference gradually increasing from top to bottom.

[0041] In addition, the rolling method also includes the following steps for assembling the rolling device on the surface of the connecting hole: Select the rolling mechanism 1, template 22, and fixing mechanism 2. Based on the hole diameter d of the connecting hole 1001 to be strengthened on the workpiece 100 and the expected interference of the rolling strengthening, select the rolling mechanism 1, template 22, and fixing mechanism 2 of appropriate size.

[0042] Install template 22. According to the specific dimensions of template 22 and the position of the mounting holes, drill the first fixing hole on workpiece 100. According to the specifications of the first fastener 5 required to fix template 22, tap the first fixing hole in workpiece 100. Then, use the first fastener 5 to fix template 22 to workpiece 100. It is necessary to ensure that the coaxiality deviation between the second hole of template 22 and the connecting hole 1001 of workpiece 100 is ≤0.001d.

[0043] Install the rolling mechanism 1. Connect the top of the mandrel 11 of the selected rolling mechanism 1 to the output end of the power mechanism 3.

[0044] Install the fixing mechanism 2. Fix the guide 21 of the selected fixing mechanism 2 to the bottom end of the base plate 42, put the guide protrusion 211 of the guide 21 into the second hole of the template 22, and make the positioning pin 221 on the template 22 precisely inserted into the positioning hole corresponding to the bottom end of the guide 21.

[0045] When performing roll forming reinforcement on the connecting hole 1001, the stroke end of the stroke-rotation composite hydraulic cylinder is activated (the stroke-rotation composite hydraulic cylinder can provide linear and rotary motion, where the stroke end activation causes the piston rod to move linearly, and the rotation end activation causes the piston rod to rotate), pushing the piston rod out. This causes the mandrel 11 fixed on the piston rod to pass sequentially through the through hole 421 on the base plate 42, the first hole 2111 on the guide member 21, and the connecting hole 1001 to be reinforced on the workpiece 100, ensuring that the entire sleeve 12 and the multiple rows of balls 13 mounted on it all pass through the connecting hole 1001. Then, the stroke-rotation composite hydraulic cylinder is activated again to rotate and pull the piston rod back, causing the sleeve 12 to approach the lower surface of the connecting hole 1001 to be reinforced on the workpiece 100 from bottom to top. When the first row of balls 13 contacts the connecting hole 1001, the bottom end face of the sleeve 12 will be in close contact with the top surface of the limiting ring 113 of the mandrel 11. The conical surface of the variable diameter section 112 will force the multiple rows of balls 13 to form a rolling reinforcement with the interference amount gradually increasing from top to bottom. As the piston rod is further rotated and pulled back, the first row of balls 13 firstly rolls the surface of the connecting hole 1001 with the set first-level interference amount, then the second row of balls 13 further rolls the surface of the connecting hole 1001 with the set second-level interference amount, and so on, until all the multiple rows of balls 13 with the progressively increasing interference amount have passed through the connecting hole 1001.

[0046] After the piston rod is fully retracted to the starting position, the stroke-rotation combined hydraulic cylinder is closed, ending the entire surface rolling strengthening process of the connecting hole 1001. The guide member 21 and all structures mounted on it are removed and moved to the next connecting hole 1001 to be strengthened. The above steps are repeated to perform surface rolling strengthening on the next connecting hole 1001. After completing the surface rolling strengthening of all connecting holes 1001 to be strengthened on the workpiece 100, the first fastener 5 on the template 22 is loosened, and the template 22 is removed.

[0047] The above embodiments merely illustrate the basic principles and characteristics of the present invention. The present invention is not limited to the above embodiments. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A device for rolling the surface of a connecting hole, characterized in that, include: The rolling mechanism (1) includes a mandrel (11), a sleeve (12) and a plurality of balls (13). The sleeve (12) is sleeved on the mandrel (11), and the plurality of balls (13) are evenly spaced and rolled on the sleeve (12). The mandrel (11) is capable of moving along its own axis and rotating along its own circumference. The mandrel (11) has a constant diameter section (111), a variable diameter section (112), and a limiting ring (113) connected sequentially from top to bottom. The cross-sectional area of ​​the constant diameter section (111) in its own axis is less than or equal to the cross-sectional area of ​​the variable diameter section (112). The cross-sectional area of ​​the variable diameter section (112) gradually increases from top to bottom. The sleeve (12) is capable of moving between the constant diameter section (111) and the variable diameter section (112). The limiting ring (113) restricts the sleeve (12) from disengaging from the end of the variable diameter section (112) away from the constant diameter section (111). The sleeve (12) passes through the connecting hole (1001) of the workpiece (100) from top to bottom. The workpiece (100) pushes the sleeve (12) to the equal diameter section (111) so that the ball (13) rolls against the hole wall of the connecting hole (1001). The sleeve (12) passes through the connecting hole (1001) from bottom to top. The workpiece (100) pushes the sleeve (12) to the variable diameter section (112) so that the outer circumferential surface of the mandrel (11) forces the ball (13) to press against the hole wall of the connecting hole (1001), and the rolling force of the ball (13) against the hole wall of the connecting hole (1001) gradually increases from top to bottom.

2. The connecting hole surface rolling device according to claim 1, characterized in that, The outer periphery of the sleeve (12) is provided with ball holes, the ball holes include multiple rows of ball holes evenly spaced along the axial direction of the sleeve (12), and each row of ball holes includes multiple ball holes evenly spaced along the circumferential direction of the sleeve (12), and one ball (13) is rolled in one ball hole.

3. The connecting hole surface rolling device according to claim 1, characterized in that, The connecting hole surface rolling device also includes a power mechanism (3), the output end of which is connected to the mandrel (11). The power mechanism (3) is used to drive the mandrel (11) to move along its own axis and rotate along its own circumference.

4. The connecting hole surface rolling device according to claim 3, characterized in that, The power mechanism (3) includes a drive member (31) and a transmission rod (32). One end of the transmission rod (32) is connected to the drive member (31), and the other end of the transmission rod (32) is connected to the equal diameter section (111). A stepped surface is formed between the transmission rod (32) and the equal diameter section (111). The sleeve (12) can move to the equal diameter section (111) and abut against the stepped surface. The drive member (31) is used to drive the transmission rod (32) to drive the mandrel (11) to move.

5. The connecting hole surface rolling device according to claim 3, characterized in that, The surface rolling device for the connecting hole also includes a fixing mechanism (2) and a supporting mechanism (4). The workpiece (100) is fixed below the fixing mechanism (2), and the supporting mechanism (4) is fixed above the fixing mechanism (2). The supporting mechanism (4) has an installation cavity and a through hole (421) communicating with the installation cavity. The power mechanism (3) is fixed in the installation cavity. The fixing mechanism (2) is provided with a first hole (2111). The rolling mechanism (1) passes through the first hole (2111) and the through hole (421) and is connected to the output end of the power mechanism (3).

6. The connecting hole surface rolling device according to claim 5, characterized in that, The fixing mechanism (2) includes a guide (21) and a template (22). The workpiece (100) is detachably disposed below the template (22), and the support mechanism (4) is detachably disposed above the guide (21). The guide member (21) has a through hole (2111) and a guide protrusion (211) protruding from the outer periphery of the first hole (2111) toward the template (22). The template (22) has a second hole and the guide protrusion (211) passes through the second hole. The diameter of the first hole (2111) and the connecting hole (1001) is d. The coaxiality deviation between the second hole and the connecting hole (1001) is less than or equal to 0.001d.

7. The connecting hole surface rolling device according to claim 6, characterized in that, The template (22) is provided with a positioning pin (221), and the guide (21) is provided with a positioning hole. The upper end of the positioning pin (221) is inserted into the positioning hole.

8. The connecting hole surface rolling device according to claim 6, characterized in that, The template (22) is provided with a first mounting hole, the workpiece (100) is provided with a first fixing hole, and the connecting hole surface rolling device further includes a first fastener (5), which passes through the first mounting hole and is threaded into the first fixing hole; The support mechanism (4) is provided with a second mounting hole, the guide (21) is provided with a second fixing hole, and the connecting hole surface rolling device further includes a second fastener (6), which passes through the second mounting hole and is threaded into the second fixing hole.

9. The connecting hole surface rolling device according to claim 5, characterized in that, The support mechanism (4) includes a housing (41) and a base plate (42). The housing (41) covers the base plate (42) to form the mounting cavity. The base plate (42) is provided with the through hole (421). The base plate (42) is fixed above the fixing mechanism (2).

10. A rolling method, characterized in that, The device for rolling the surface of a connecting hole as described in any one of claims 1 to 9 comprises the following steps: S1: Move the mandrel (11) so that the mandrel (11) passes through the connecting hole (1001) on the workpiece (100) from top to bottom, ensuring that the entire sleeve (12) and the multiple rows of balls (13) mounted thereon pass through the connecting hole (1001). S2: The mandrel (11) is rotated and pulled back, so that the sleeve (12) approaches the lower surface of the connecting hole (1001) of the workpiece (100) from bottom to top. When the first row of balls (13) contacts the connecting hole (1001), the bottom end face of the sleeve (12) will be close to the top surface of the limiting ring (113) of the mandrel (11). The outer circumference of the variable diameter section (112) will force the multiple rows of balls (13) to form rolling reinforcement with the interference gradually increasing from top to bottom.

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