A machining center drilling hydraulic clamp

Abstract

The application discloses a machining center drilling hydraulic clamp and belongs to the technical field of hydraulic clamps. The machining center drilling hydraulic clamp comprises an oil cylinder seat fixed with a positioning mandrel at the top, a rotatable adjusting ring is sleeved on the oil cylinder seat, an annular cavity and a lifting ring embedded in the annular cavity are arranged in the oil cylinder seat, the lifting ring divides the annular cavity into an upper cavity and a lower cavity, a first channel communicating with the lower cavity and a second channel communicating with the upper cavity are arranged in the oil cylinder seat, a plurality of adjusting rods are fixed to the outer peripheral wall of the lifting ring, a plurality of spiral grooves are arranged on the inner side wall of the adjusting ring, the adjusting rods pass through the through holes in the side wall of the oil cylinder seat and are embedded in the spiral grooves, the lifting movement of the lifting ring is converted into the rotary movement of the adjusting ring, a mounting cavity is further arranged in the oil cylinder seat, a first rack and a second rack are slidably arranged in the mounting cavity through gear meshing, a limiting column is fixed to the top of the first rack, a spring is arranged at the lower end of the first rack, and a blocking block for blocking the first channel is fixed to the bottom of the second rack. The machining center drilling hydraulic clamp realizes the automatic rotation alignment and automatic positioning of workpieces and improves the machining efficiency.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic clamping technology and relates to a hydraulic clamping fixture for drilling in machining centers. Background Technology

[0002] In the mechanical manufacturing process, fixtures are important devices used to position and securely clamp workpieces in a reasonable location to complete the required processing steps. Especially in modern flexible manufacturing systems, which involve a large number of clamping operations, the role of fixtures is becoming increasingly critical, and their performance directly affects the processing quality of parts, production efficiency, and manufacturing costs.

[0003] In existing drilling processes, high workpiece positioning accuracy is required. A common positioning process is as follows: The operator first places the workpiece into the fixture and visually adjusts its approximate position. Then, a separate positioning pin is inserted from top to bottom into the pre-set through-hole on the workpiece, with the lower end of the positioning pin extending beyond the lower surface of the workpiece. The fixture has a backing plate, and the lower end of the workpiece rests against the upper end of the backing plate, which has a positioning hole. Initially, the workpiece positioning hole and the backing plate positioning hole are not aligned, and the lower end of the positioning pin rests against the upper surface of the backing plate. The operator rotates the workpiece, causing the lower end of the positioning pin to slide on the backing plate surface. When the two positioning holes are aligned, the positioning pin moves downward under gravity, and its lower end is embedded in the positioning hole of the backing plate. At this time, the upper part of the positioning pin is still inserted in the workpiece positioning hole, thus completing the precise angular positioning. Afterward, the positioning pin needs to be removed from the workpiece and the backing plate, and the workpiece is then clamped by the fixture before drilling can begin.

[0004] The above method has the following shortcomings: each time a new workpiece is clamped, the steps of "inserting the positioning pin - rotating to align - removing the positioning pin" must be repeated. The repeated picking and putting in of the independent positioning pin is cumbersome, increases the intensity of manual labor, reduces production efficiency, and the entire positioning process has a low degree of automation, which is difficult to meet the requirements of modern efficient and automated production. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a hydraulic drilling fixture for machining centers. This solves the technical problems mentioned in the background art, such as the need for manual repeated handling of independent positioning pins in existing fixture positioning methods, which are cumbersome, inefficient, and have a low degree of automation.

[0006] The objective of this invention can be achieved through the following technical solutions: A hydraulic chuck for drilling in a machining center includes a cylinder seat with a positioning mandrel fixed at the top, a rotatable adjusting ring sleeved on the cylinder seat, an annular cavity inside the cylinder seat, and a lifting ring embedded in the annular cavity, the lifting ring dividing the annular cavity into an upper cavity and a lower cavity; The cylinder seat is provided with a first channel connecting the lower cavity and a second channel connecting the upper cavity; the cylinder seat is also provided with an installation cavity and an adjustment channel connecting the installation cavity, the adjustment channel passing through and connecting the first channel; The outer peripheral wall of the lifting ring is fixed with several equally spaced adjusting rods, the side wall of the cylinder seat is provided with several through holes for the adjusting rods to pass through, the inner side wall of the adjusting ring is provided with several spiral grooves, and one end of the adjusting rod is embedded in the corresponding spiral groove. The mounting cavity is slidably provided with a first rack and a second rack. A gear that meshes with the first rack and the second rack is mounted in the mounting cavity through a rotating shaft. A limiting post that can pass through the top of the cylinder seat is fixed to the top of the first rack. A spring is fixed between the lower end and the bottom wall of the mounting cavity. A sealing block extending into the adjustment channel is fixed to the bottom of the second rack. The sealing block is used to block the connection between the adjustment channel and the mounting cavity. When the adjusting ring rotates until the workpiece positioning hole aligns with the limiting post, the limiting post rises under the action of the spring and extends into the positioning hole. At the same time, the sealing block moves in the opposite direction to cut off the liquid flow in the first channel.

[0007] By setting up a first channel and a second channel to connect the lower chamber and the upper chamber respectively, the lifting ring is hydraulically driven to rise and fall. An adjusting rod is installed on the outer circumference of the lifting ring, and a spiral groove is installed on the inner side wall of the adjusting ring. The adjusting rod passes through a through hole in the side wall of the cylinder seat and embeds itself in the spiral groove, allowing the lifting motion of the lifting ring to be automatically converted into the rotational motion of the adjusting ring. This achieves automatic rotational adjustment of the workpiece, eliminating the need for manual rotational alignment. Simultaneously, by setting up a first rack, a second rack, a gear, a limiting post, a sealing block, and a spring in the mounting cavity, when the workpiece rotates to align its positioning hole with the limiting post, the limiting post automatically rises under the action of the spring and embeds itself in the positioning hole, completing precise angular positioning of the workpiece. This eliminates the need for manual insertion of a positioning pin, simplifying operation and increasing positioning efficiency. At the same time, the sealing block moves synchronously in the opposite direction under the gear and rack drive, cutting off the fluid flow in the first channel and immediately stopping the lifting ring. This effectively prevents the adjusting ring from continuing to drive the workpiece to rotate after positioning, thus avoiding the squeezing force and wear between the limiting post and the workpiece, protecting both the workpiece and the limiting post, and extending the service life of the fixture.

[0008] Preferably, the inner wall of the adjusting ring is provided with a plurality of vertical grooves, the upper end of which is connected to the lower end of the spiral groove.

[0009] Preferably, the top of the positioning mandrel has a frustum, and an expansion sleeve is fitted on the frustum. The cylinder seat is provided with a drive mechanism that drives the expansion sleeve to move up and down along the axial direction of the frustum, so that the expansion sleeve expands or contracts radially. The cylinder seat is provided with a third channel and a fourth channel for supplying oil to the drive mechanism. The cylinder seat is provided with three corner cylinders that are evenly distributed in a ring. The telescopic rod of the corner cylinder is fixed with a clamping block.

[0010] By incorporating an expansion sleeve, a frustum, a drive mechanism, a third channel, and a fourth channel, radial expansion or contraction of the expansion sleeve during its axial movement along the frustum is achieved, enabling flexible expansion and positioning of the workpiece. Simultaneously, a corner cylinder and clamping blocks are installed to provide secondary clamping and fixation of the workpiece end face after the expansion sleeve is positioned. Compared to existing technologies that rely solely on expansion sleeve locking, this method of first providing flexible expansion followed by rigid clamping ensures stable workpiece clamping while avoiding damage caused by excessive expansion force in the single expansion sleeve positioning method, thus balancing fixing efficiency and workpiece protection.

[0011] Preferably, the cylinder seat is provided with an adjustment chamber, and the driving mechanism includes a piston block slidably disposed in the adjustment chamber. The piston block divides the adjustment chamber into a first oil chamber and a second oil chamber. The third channel communicates with the first oil chamber, and the fourth channel communicates with the second oil chamber. The positioning mandrel has a sliding groove at the bottom and a sliding hole at the top that connects the sliding groove and the through-truncated cone. The upper end of the cylinder seat has a connecting port that connects the first oil chamber and the sliding groove. The piston block is fixed with a connecting block embedded in the connection port. The connecting block is used to block the connection port from communicating with the first oil chamber. The connecting block is fixed with a cylinder rod and an adjusting rod in sequence. The cylinder rod is embedded in the slide groove, and the adjusting rod extends to the outside of the slide hole and is fixedly connected to the expansion sleeve.

[0012] Preferably, the cylinder seat includes a base plate, a base, and an annular support. The base is fixed to the top of the base plate, the support is fixed to the top of the base, the positioning spindle is fixed to the top of the base and its upper end extends outside the support, and the adjusting ring is rotatably sleeved on the outer peripheral wall of the support. The through hole is opened on the side wall against the mountain, the annular cavity and the mounting cavity are located inside the mountain, and the first channel, the second channel, the adjustment channel, the adjustment cavity and the connection port are all located inside the base; The first, second, and third channels all extend outward and connect to the base plate. The base plate has a fifth channel and three unlocking channels that are respectively connected to the three corner cylinders. The fourth channel connects to the base plate and is connected to the fifth channel. All three unlocking channels are connected to the fifth channel. The base plate also has three locking channels that are respectively connected to the three corner cylinders. The base plate has a main channel, and all three locking channels are connected to the main channel.

[0013] By setting a base plate, the other ends of the first, second, and third channels are extended into the base plate and connected to the outside of the base plate, realizing centralized connection and management of multiple oil channels and simplifying the layout of external pipelines. A fifth channel is set in the base plate, so that the fourth channel can be connected to the unlocking channels of multiple corner cylinders at the same time through the fifth channel, realizing the synchronous unlocking action of expansion sleeve contraction and corner cylinder clamping block reset, improving the efficiency of parts changing and meeting the requirements of high-efficiency automated production cycle.

[0014] Preferably, the top of the adjusting ring is provided with an annular abutment, and the upper end surface of the abutment and the upper end surface of the backing are located on the same horizontal plane.

[0015] By setting an annular abutment at the top of the adjusting ring and making the upper end face of the abutment flush with the upper end face of the backing, the contact area between the adjusting ring and the lower end face of the workpiece is increased, which improves the friction when the adjusting ring drives the workpiece to rotate, making the workpiece rotate more accurately and stably, and ensuring positioning accuracy.

[0016] Preferably, one end of the adjusting rod is fixed with a steel ball positioning screw, one end of the steel ball positioning screw is embedded in the spiral groove, and the steel ball end of the steel ball positioning screw is in contact with the inner sidewall of the spiral groove.

[0017] By setting a steel ball positioning screw at the end of the adjusting rod, one end of the steel ball of the positioning screw is in contact with the inner wall of the spiral groove, which converts sliding friction into rolling friction. This reduces the frictional resistance when the adjusting rod moves in the spiral groove, making the lifting ring rise and fall and the adjusting ring rotate more smoothly and flexibly. At the same time, it reduces wear and extends the service life of the parts.

[0018] Preferably, the inner wall of the adjusting ring is fixed with a plurality of limiting rods distributed in a ring at equal intervals, and the outer wall of the backing has a plurality of limiting grooves, with one end of each limiting rod embedded in a corresponding limiting groove.

[0019] By setting a limiting rod on the inner side wall of the adjusting ring and opening a corresponding limiting groove on the outer side wall of the backing, the limiting rod is embedded in the limiting groove, thus achieving axial limiting of the adjusting ring, preventing the adjusting ring from moving up and down during rotation, and ensuring the stability of the adjusting ring's rotational movement and the accuracy of the workpiece positioning.

[0020] Preferably, the top of the support has an installation groove, a mounting block is fixed in the installation groove, the installation cavity is set in the mounting block, the top of the mounting block has a circular hole for the limiting post to pass through, the mounting block has a connecting hole for the sealing block to pass through, and the connecting hole is connected to the adjustment channel; both sides of the first rack are provided with first guide blocks, both sides of the inner wall of the installation cavity have first guide grooves, and the first guide blocks are slidably embedded in the corresponding first guide grooves; both sides of the second rack are provided with second guide blocks, both sides of the inner wall of the installation cavity have second guide grooves, and the second guide blocks are slidably embedded in the corresponding second guide grooves.

[0021] By placing the mounting cavity within a separate mounting block and fixing the mounting block to the mounting groove at the top of the support, a modular, separate structure is formed between the mounting block and the support. When the first or second rack within the mounting cavity needs replacement due to wear from long-term use, only the mounting block needs to be removed, eliminating the need to replace the entire support, thus reducing maintenance costs and difficulty and improving the maintainability of the fixture. Simultaneously, the sliding fit between the first guide block and the first guide groove, and the second guide block and the second guide groove, ensures the straightness and stability of the reciprocating motion of the first and second racks.

[0022] Preferably, a guide post is fixed to the bottom wall of the mounting cavity, a circular groove is opened at the lower end of the first rack for the guide post to be embedded, and the spring is sleeved on the guide post.

[0023] By setting a guide post on the bottom wall of the mounting cavity, opening a circular groove at the lower end of the first rack to cooperate with the guide post, and sleeve the spring on the guide post, the spring is guided and limited, preventing the spring from deflecting or twisting during compression or extension, ensuring the stable output of the spring force, and thus ensuring the reliability of the extension and retraction of the limit post.

[0024] The main technical effects of this invention are reflected in the following aspects: 1. This invention utilizes a hydraulic drive structure formed by an annular cavity, a lifting ring, a first channel, and a second channel. A motion conversion mechanism, consisting of a spiral groove and an adjusting rod, is installed between the lifting ring and the adjusting ring. This allows the operator to simply place the workpiece initially on the adjusting ring and drive the lifting ring upwards via the first channel, automatically rotating both the adjusting ring and the workpiece without manual alignment. Simultaneously, a positioning mechanism consisting of a limiting post, a sealing block, a first rack, a second rack, and gears is installed within the mounting cavity. When the workpiece rotates to align its positioning hole with the limiting post, the limiting post automatically rises under spring pressure and extends into the positioning hole for precise angular positioning, eliminating the need for manual insertion of a positioning pin. Simultaneously, the sealing block moves in the opposite direction to cut off the fluid flow in the first channel, immediately stopping the lifting ring. This effectively prevents the adjusting ring from continuing to rotate the workpiece after positioning, thus avoiding pressure and wear between the limiting post and the workpiece positioning hole. The entire positioning process is automated, significantly simplifying operations, reducing manual labor intensity, improving production efficiency, and achieving highly efficient automated positioning.

[0025] 2. This invention, by incorporating an expansion sleeve, a driving mechanism, a third channel, and a fourth channel, combined with multiple corner cylinders mounted on the base plate, achieves a secondary positioning and locking method. This involves first flexibly pre-positioning the workpiece through radial expansion of the expansion sleeve, and then rigidly clamping and fixing the workpiece end face using the corner cylinders driving the clamping block. This ensures stable workpiece clamping while avoiding damage caused by a single expansion sleeve positioning method. Furthermore, the interconnected design of the fifth and fourth channels within the base plate, along with multiple unlocking channels, enables synchronized unlocking actions during expansion sleeve retraction and corner cylinder clamping block resetting, further improving workpiece changing efficiency and meeting the requirements of modern, efficient, and automated production. Attached Figure Description

[0026] Figure 1 This is a structural schematic diagram of an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure when the workpiece is clamped according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the exploded structure of the mountain in an embodiment of the present invention; Figure 4 This is a cross-sectional view of the cylinder seat according to an embodiment of the present invention. Figure 1 ; Figure 5 This is a cross-sectional view of the cylinder seat according to an embodiment of the present invention. Figure 2 ; Figure 6 This is an assembly cross-sectional view of the support and base according to an embodiment of the present invention; Figure 7 This is an embodiment of the present invention. Figure 6 Enlarged view of point A in the middle; Figure 8 This is an exploded structural diagram of the mounting block, first rack, limiting post, second rack, and sealing block according to an embodiment of the present invention; Figure 9 This is a cross-sectional view of the mounting block according to an embodiment of the present invention; Figure 10 This is an assembly cross-sectional view of the base plate and the base according to an embodiment of the present invention. Figure 1 ; Figure 11 This is an assembly cross-sectional view of the base plate and the base according to an embodiment of the present invention. Figure 2 ; Figure 12 This is a cross-sectional view of the cylinder seat according to an embodiment of the present invention. Figure 3 ; Figure 13 This is an exploded structural diagram of the cylinder seat according to an embodiment of the present invention; Figure 14 This is a cross-sectional view of the cylinder seat according to an embodiment of the present invention. Figure 4 ; Figure 15This is a schematic diagram of the assembly structure of the base and the support in an embodiment of the present invention; Figure 16 This is a cross-sectional view of the workpiece being clamped according to an embodiment of the present invention; Figure 17 This is a cross-sectional view of the base plate according to an embodiment of the present invention.

[0027] Explanation of reference numerals in the attached drawings: 1. Cylinder seat; 11. Positioning spindle; 111. Frustum; 112. Slide groove; 113. Slide hole; 2. Base; 21. First channel; 22. Second channel; 23. Adjustment channel; 24. Third channel; 25. Fourth channel; 26. Adjustment chamber; 261. First oil chamber; 262. Second oil chamber; 27. Connection port; 3. Backing; 31. Adjusting ring; 311. Spiral groove; 312. Vertical groove; 313. Abutment part; 314. Limiting rod; 32. Annular cavity; 321. Upper cavity; 322. Lower cavity; 33. Through hole; 34. Limiting groove; 35. Mounting groove; 4. Base plate; 41. Corner cylinder; 411. Clamping block; 42. Fifth channel; 43. Unlocking channel; 44. Locking channel; 45. Main channel; 5. Mounting block; 51. Mounting cavity; 511. Guide post; 512. Spring; 513. First guide groove; 514. Second guide groove; 52. First rack; 521. Limiting post; 522. Circular groove; 523. First guide block; 53. Second rack; 531. Sealing block; 532. Second guide block; 54. Gear; 55. Circular hole; 56. Connecting hole; 57. Rotating shaft; 6. Piston block; 61. Connecting block; 62. Hydraulic cylinder rod; 63. Adjusting rod; 64. Expansion sleeve; 7. Lifting ring; 71. Adjusting rod; 711. Steel ball positioning screw. Detailed Implementation

[0028] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0029] like Figure 1-5 As shown in Figure 16, a hydraulic chuck for drilling in a machining center includes a cylinder seat 1 with a positioning spindle 11 fixed at the top. A rotatable adjusting ring 31 is fitted on the cylinder seat 1. An annular cavity 32 is provided inside the cylinder seat 1. A lifting ring 7 is embedded in the annular cavity 32, which divides the annular cavity 32 into an upper cavity 321 and a lower cavity 322. An annular sealing groove is formed on the outer peripheral wall of the lifting ring 7, and an annular sealing ring is embedded in the annular sealing groove. The cylinder seat 1 is provided with a first channel 21 that connects to the lower cavity 322 and a second channel 22 that connects to the upper cavity 321. The hydraulic oil in the first channel 21 enters the lower cavity 322 and can push the lifting ring 7 to slide upward along the annular cavity 32. The hydraulic oil in the second channel 22 enters the upper cavity 321 and can push the lifting ring 7 to slide downward along the annular cavity 32. The cylinder seat 1 is also provided with an installation cavity 51 and an adjustment channel 23 that connects to the installation cavity 51. The adjustment channel 23 passes through and connects to the first channel 21. The outer peripheral wall of the lifting ring 7 is fixed with several equally spaced adjusting rods 71. In this embodiment of the invention, the outer peripheral wall of the lifting ring 7 is fixed with three adjusting rods 71. One end of the adjusting rod 71 has a threaded section. The outer peripheral wall of the lifting ring 7 has a threaded groove for threaded installation of the threaded section. The side wall of the cylinder seat 1 has three through holes 33 for the adjusting rods 71 ​​to pass through. The inner side wall of the adjusting ring 31 is provided with several spiral grooves 311. One end of the adjusting rod 71 is embedded in the corresponding spiral groove 311. The inner side wall of the adjusting ring 31 is provided with several vertical grooves 312. The upper end of the vertical groove 312 is connected to the lower end of the spiral groove 311. The linear lifting motion of the lifting ring 7 is converted into the rotational motion of the adjusting ring 31 through the cooperation of the adjusting rod 71 and the spiral groove 311. The spiral angle design of the spiral groove 311 determines the rotation angle of the adjusting ring 31 corresponding to the unit stroke of the lifting ring 7. During the lifting process, the adjusting rod 71 and the through hole 33 cooperate to limit the lifting range of the lifting ring 7. During the lifting process, the outer peripheral wall of the lifting ring 7 will always block the through hole 33. Reference Figure 6-10 A first rack 52 and a second rack 53 are slidably disposed within the mounting cavity 51. A gear 54, meshing with the first rack 52 and the second rack 53, is mounted within the mounting cavity 51 via a rotating shaft 57. The gear 54 is sleeved on the rotating shaft 57. When the first rack 52 moves up and down, it drives the gear 54 to rotate. The gear 54 is located between the first rack 52 and the second rack 53. When the first rack 52 rises, it drives the second rack 53 to descend by the same height via the gear 54. A limiting post 5 that can pass through the top of the cylinder seat 1 is fixed to the top of the first rack 52. 21. A spring 512 is fixed between the lower end and the bottom wall of the mounting cavity 51. A sealing block 531 extending into the adjustment channel 23 is fixed at the bottom of the second rack 53. In the initial state, the sealing block 531 is used to block the connection between the adjustment channel 23 and the mounting cavity 51 to prevent hydraulic oil from entering the interior of the mounting cavity 51. The outer peripheral wall of the sealing block 531 is in contact with the outer peripheral wall of the adjustment channel 23. The outer peripheral wall of the sealing block 531 is also provided with a sealing groove, and a sealing rubber ring is embedded in the annular sealing ring. When the adjusting ring 31 rotates until the workpiece positioning hole aligns with the limiting post 521, the limiting post 521 rises and extends into the workpiece positioning hole under the action of the spring 512. At the same time, the sealing block 531 moves in the opposite direction to cut off the fluid flow in the first channel 21, thereby stopping the movement of the lifting ring 7. At this time, the upper end of the second rack 53 abuts against the top wall inside the mounting cavity 51. When the hydraulic oil in the first channel 21 passes through, it will push the sealing block 531 upward. However, since the upper end of the second rack 53 abuts against the top wall inside the mounting cavity 51, the second rack 53 cannot move beyond the limited stroke.

[0030] like Figure 1 , 11 As shown in Figures 1 and 12, the cylinder seat 1 includes a base plate 4, a base 2, and an annular support 3. The base 2 is fixed to the top of the base plate 4, the support 3 is fixed to the top of the base 2, the positioning spindle 11 is fixed to the top of the base 2 and its upper end extends to the outside of the support 3, and the adjusting ring 31 is rotatably sleeved on the outer peripheral wall of the support 3. The top of the positioning mandrel 11 has a frustum 111, and an expansion sleeve 64 is fitted on the frustum 111. The cylinder seat 1 is provided with a drive mechanism that drives the expansion sleeve 64 to move up and down along the axial direction of the frustum 111, so that the expansion sleeve 64 expands or contracts radially. The cylinder seat 1 is provided with a third channel 24 and a fourth channel 25 for supplying oil to the drive mechanism. Three corner cylinders 41 are arranged in a ring with equal spacing on the cylinder seat 1. The telescopic rod of the corner cylinder 41 is fixed with a clamping block 411.

[0031] Reference Figure 12-15 and Figure 17 The base 2 has an adjustment chamber 26. The drive mechanism includes a piston block 6 that is slidably disposed in the adjustment chamber 26. The piston block 6 divides the adjustment chamber 26 into a first oil chamber 261 and a second oil chamber 262. A third channel 24 connects to the first oil chamber 261, and a fourth channel 25 connects to the second oil chamber 262. The hydraulic oil in the third channel 24 enters the first oil chamber 261, which can push the piston block 6 downward. The hydraulic oil in the fourth channel 25 enters the second oil chamber 262, which can push the piston block 6 upward. The piston block 6 divides the regulating chamber 26 into a first oil chamber 261 and a second oil chamber 262, which are supplied with oil through the third channel 24 and the fourth channel 25, respectively, to achieve stable lifting and lowering drive of the piston block 6. Through the sequential connection of the connecting block 61, the cylinder rod 62 and the regulating rod 63, the lifting and lowering movement of the piston block 6 is reliably transmitted to the expansion sleeve 64. The structure is compact and the transmission path is clear, which ensures the stability and reliability of the expansion or contraction action of the expansion sleeve 64.

[0032] The positioning spindle 11 has a sliding groove 112 at the bottom and a sliding hole 113 at the top that connects the sliding groove 112 and the through frustum 111. The upper end of the base 2 has a connection port 27 that connects the first oil cavity 261 and the sliding groove 112. A connecting block 61 is fixed on the top of the piston block 6 and embedded in the connecting port 27. The connecting block 61 is used to block the communication between the connecting port 27 and the first oil chamber 261. The outer wall of the connecting block 61 is in contact with the inner peripheral wall of the connecting port 27. Both the outer walls of the connecting block 61 and the piston block 6 have annular sealing grooves, and annular sealing rings are embedded in both sealing grooves. The top of the connecting block 61 is sequentially fixed with a hydraulic cylinder rod 62 and an adjusting rod 63. The hydraulic cylinder rod 62 is embedded in the slide groove 112, and the adjusting rod 63 extends to the outside of the slide hole 113 and is fixedly connected to the expansion sleeve 64. The through hole 33 through which the adjusting rod 71 passes and the limiting groove 34 into which the limiting rod 314 is embedded are both opened on the side wall of the backing 3. The annular cavity 32 and the mounting cavity 51 are located inside the backing 3. The first channel 21, the second channel 22 and the adjusting channel 23 are all located inside the base 2. The first channel 21, the second channel 22, and the third channel 24 all extend outward and connect to the base plate 4. The base plate 4 has a fifth channel 42 and three unlocking channels 43 that are respectively connected to the three corner cylinders 41. The fourth channel 25 connects to the base plate 4 and is connected to the fifth channel 42. All three unlocking channels 43 are connected to the fifth channel 42. By inputting hydraulic oil into the fifth channel 42, the hydraulic oil in the fifth channel 42 enters the three unlocking channels 43 and the fourth channel 25 respectively, realizing the synchronous unlocking action of the piston block 6 rising and the corner cylinder 41 clamping block 411 resetting. The base plate 4 also has three locking channels 44 that are respectively connected to the three corner cylinders 41. The base plate 4 has a main channel 45. All three locking channels 44 are connected to the main channel 45. By inputting hydraulic oil into the main channel 45, the hydraulic oil in the main channel 45 enters the corresponding corner cylinder 41 through the three locking channels 44, thereby causing the three corner cylinders 41 to drive the clamping block 411 to rotate and descend.

[0033] like Figure 3 , 6 As shown in Figure 13, the top of the adjusting ring 31 is provided with an annular abutment 313. The upper end face of the abutment 313 is on the same horizontal plane as the upper end face of the backing 3. One end of the adjusting rod 71 is fixed with a steel ball positioning screw 711. One end of the steel ball positioning screw 711 is embedded in the spiral groove 311. The steel ball end of the steel ball positioning screw 711 is in contact with the inner side wall of the spiral groove 311. Several limiting rods 314 are fixed on the inner side wall of the adjusting ring 31 in an annular and equally spaced manner. Several limiting grooves 34 are opened on the outer wall of the backing 3. One end of the limiting rod 314 is embedded in the corresponding limiting groove 34.

[0034] like Figure 7-9As shown in Figure 15, the top of the support 3 has an installation groove 35, and an installation block 5 is fixed in the installation groove 35. The installation cavity 51 is set in the installation block 5. The top of the installation block 5 has a circular hole 55 for the limit post 521 to pass through. The installation block 5 has a connecting hole 56 for the sealing block 531 to pass through. The connecting hole 56 is connected to the adjustment channel 23. The first rack 52 has a first guide block 523 on both sides. The inner side walls of the installation cavity 51 have a first guide groove 513. The first guide block 523 slides into the corresponding first guide groove 513. The second rack 53 has a second guide block 532 on both sides. The inner side walls of the installation cavity 51 have a second guide groove 514. The second guide block 532 slides into the corresponding second guide groove 514. The bottom wall of the installation cavity 51 is fixed with a guide post 511. The lower end of the first rack 52 has a circular groove 522 for the guide post 511 to be inserted. The spring 512 is sleeved on the guide post 511.

[0035] It should be noted that the hydraulic drilling fixture of the machining center of the present invention is used to clamp non-standard workpieces with specific structures.

[0036] The specific operation method of this invention is as follows: Clamping phase: The operator places the workpiece with its center hole on the positioning mandrel 11, and the lower end face of the workpiece naturally rests on the annular abutment 313 at the top of the adjusting ring 31. At this time, the workpiece can rotate together with the adjusting ring 31. Since the workpiece has not been precisely aligned, the positioning hole on it is not yet aligned with the limiting post 521 at the top of the cylinder seat 1. The lower end face of the workpiece presses down the limiting post 521, and the limiting post 521 retracts into the cylinder seat 1 against the elastic force of the spring 512. The spring 512 is in a compressed and stored state. It should be noted that when the operator places the workpiece, they will initially align the positioning hole on the workpiece with the limiting post 521, so the deviation is usually not too large, only requiring the workpiece to rotate a small angle.

[0037] Hydraulic oil is introduced into the lower cavity 322 of the annular cavity 32 through the first channel 21. The hydraulic oil pushes the lifting ring 7 to slide upward along the annular cavity 32. When the lifting ring 7 rises, the adjusting rod 71 fixed on its outer peripheral wall rises together. After the adjusting rod 71 passes through the through hole 33 on the side wall of the cylinder seat 1, its end is embedded in the spiral groove 311 on the inner side wall of the adjusting ring 31. When the adjusting rod 71 rises along the spiral groove 311, the circumferential component force applied by the spiral groove 311 to the adjusting rod 71 drives the adjusting ring 31 to rotate around its axis.

[0038] As the adjusting ring 31 rotates, the friction between the abutment part 313 and the lower end face of the workpiece drives the workpiece to rotate synchronously. As the workpiece rotates, the positioning hole on it gradually approaches the position of the limiting post 521.

[0039] When the workpiece rotates with the adjusting ring 31 until its positioning hole is completely aligned with the limiting post 521, the limiting post 521 loses the pressing constraint of the lower end face of the workpiece. Under the elastic force of the spring 512, the first rack 52 drives the limiting post 521 to rise synchronously. The top of the limiting post 521 passes through the round hole 55 on the top of the mounting block 5 and is embedded in the positioning hole of the workpiece, thus completing the precise angular positioning of the workpiece.

[0040] At the same time, the first rack 52 rises and drives the second rack 53 to descend synchronously in the opposite direction through the meshing of the gear 54. The sealing block 531 fixed at the lower end of the second rack 53 also descends. The sealing block 531 moves further down from the initial sealing installation cavity 51 position to block and cut off the oil supply path of the first channel 21. The sealing block 531 blocks the first channel 21, that is, cuts off the oil supply path from the first channel 21 to the lower cavity 322 of the annular cavity 32. After the lifting ring 7 loses the hydraulic driving force, it immediately stops rising, and the adjusting ring 31 stops rotating.

[0041] After the workpiece angle is positioned, hydraulic oil is introduced into the first oil chamber 261 through the third channel 24, pushing the piston block 6 to slide down along the adjustment chamber 26. The piston block 6 moves downward, and in turn, through the connecting block 61 and the oil cylinder rod 62, it drives the adjustment rod 63 to move downward.

[0042] Adjusting the pull rod 63 pulls the expansion sleeve 64 downward, causing the expansion sleeve 64 to slide downward along the frustum 111 at the top of the positioning mandrel 11. Since the frustum 111 is a cone-shaped structure with a smaller top and a larger bottom, the expansion sleeve 64 is radially expanded by the frustum 111 during the descent, expanding outward and applying a uniform radial tension force to the inner wall of the center hole of the workpiece, thereby achieving flexible pre-positioning of the workpiece.

[0043] After the expansion sleeve 64 completes its pre-positioning, oil is supplied to the three corner cylinders 41 through the three locking channels 44 in the base plate 4, driving the telescopic rods of the corner cylinders 41 to move downwards, causing the clamping block 411 to press against the upper edge of the workpiece. The three corner cylinders 41 are distributed in a ring with equal spacing, forming a uniform axial clamping force on the workpiece, thus completing the rigid clamping and fixing of the workpiece. At this time, the workpiece is firmly clamped and can be used for subsequent drilling.

[0044] Unlike existing technologies that rely solely on the expansion sleeve 64 to provide tension force for simultaneous positioning and clamping, this invention employs a "soft first, then hard" two-stage clamping strategy. The expansion sleeve 64 only needs to provide a moderate tension force sufficient to eliminate radial clearance in the workpiece, serving a precise centering function, and does not bear the task of resisting drilling cutting forces; the cutting forces during drilling are borne by the axial clamping forces provided by the three corner cylinders 41. This division of labor design ensures positioning accuracy while avoiding damage or deformation to the inner wall of the workpiece's central hole caused by excessive tension force from the expansion sleeve 64.

[0045] Parts replacement stage After processing is complete, the workpiece needs to be loosened in order to replace the next workpiece.

[0046] Oil is simultaneously supplied to the fourth channel 25 and the three unlocking channels 43 through the fifth channel 42 in the base plate 4. One path of hydraulic oil enters the second oil chamber 262 through the fourth channel 25, pushing the piston block 6 to move upward. Through the connecting block 61, the cylinder rod 62, and the adjusting rod 63, the expansion sleeve 64 rises. After the expansion sleeve 64 moves upward along the frustum 111, it contracts radially, releasing the center hole of the workpiece.

[0047] At the same time, another hydraulic oil enters the three unlocking channels 43 through the fifth channel 42, driving the extension rods of the three corner cylinders 41 to reset upwards, causing the clamping block 411 to detach from the upper surface of the workpiece.

[0048] Since the fourth channel 25 and the three unlocking channels 43 are all connected to the fifth channel 42, the contraction of the expansion sleeve 64 and the release of the corner cylinder 41 are completely synchronized, greatly shortening the auxiliary time for component replacement. The base plate 4, as an integrated confluence structure of multiple oil channels, has a fifth channel 42 inside that acts as the "unlocking mother channel." The fourth channel 25 and the three unlocking channels 43 all originate from the fifth channel 42. When oil is supplied to the fifth channel 42, the hydraulic oil is simultaneously distributed to the expansion sleeve 64 drive mechanism and the three corner cylinders 41, achieving synchronous unlocking of the expansion sleeve 64 and the corner cylinders 41.

[0049] After the workpiece is removed, hydraulic oil is introduced into the upper cavity 321 of the annular cavity 32 through the second channel 22, pushing the lifting ring 7 to slide down and reset along the annular cavity 32. When the lifting ring 7 descends, the adjusting rod 71 moves downward along the spiral groove 311 and the vertical groove 312, driving the adjusting ring 31 to rotate in the opposite direction and return to the initial angle position, preparing for the next clamping. At the same time, the limiting post 521 is in the extended state. When the next workpiece is placed, the lower end face of the workpiece presses down the limiting post 521, and the spring 512 enters the compression and energy storage state again, preparing for the next positioning.

[0050] Of course, the above are just typical examples of this application. In addition, this application may have many other specific implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed in this application.

Claims

1. A hydraulic chuck for drilling in a machining center, comprising a cylinder seat (1) with a positioning mandrel (11) fixed at its top, characterized in that, A rotatable adjusting ring (31) is fitted on the cylinder seat (1). An annular cavity (32) is provided inside the cylinder seat (1). A lifting ring (7) is embedded in the annular cavity (32). The lifting ring (7) divides the annular cavity (32) into an upper cavity (321) and a lower cavity (322). The cylinder seat (1) is provided with a first channel (21) connecting the lower cavity (322) and a second channel (22) connecting the upper cavity (321); the cylinder seat (1) is also provided with an installation cavity (51) and an adjustment channel (23) connecting the installation cavity (51), the adjustment channel (23) passing through and connecting the first channel (21); The outer peripheral wall of the lifting ring (7) is fixed with several equally spaced adjusting rods (71), the side wall of the cylinder seat (1) is provided with several through holes (33) for the adjusting rods (71) to pass through, the inner side wall of the adjusting ring (31) is provided with several spiral grooves (311), and one end of the adjusting rod (71) is embedded in the corresponding spiral groove (311). A first rack (52) and a second rack (53) are slidably arranged in the mounting cavity (51). A gear (54) that meshes with the first rack (52) and the second rack (53) is installed in the mounting cavity (51) via a rotating shaft (57). A limiting post (521) that can pass through the top of the cylinder seat (1) is fixed to the top of the first rack (52). A spring (512) is fixed between the lower end and the bottom wall of the mounting cavity (51). A sealing block (531) that extends into the adjustment channel (23) is fixed to the bottom of the second rack (53). The sealing block (531) is used to block the communication between the adjustment channel (23) and the mounting cavity (51). When the adjusting ring (31) rotates to align the workpiece positioning hole with the limiting post (521), the limiting post (521) rises and extends into the workpiece positioning hole under the action of the spring (512), and at the same time the sealing block (531) moves in the opposite direction to cut off the liquid flow of the first channel (21); The cylinder seat (1) includes a base plate (4), a base (2) and an annular support (3). The base (2) is fixed to the top of the base plate (4), the support (3) is fixed to the top of the base (2), the positioning spindle (11) is fixed to the top of the base (2) and its upper end extends to the outside of the support (3), the adjusting ring (31) is rotatably sleeved on the outer peripheral wall of the support (3), the through hole (33) is opened on the side wall of the support (3), and the annular cavity (32) and the mounting cavity (51) are located inside the support (3). The top of the adjusting ring (31) is provided with an annular abutment (313), and the upper end surface of the abutment (313) is on the same horizontal plane as the upper end surface of the backing (3); The top of the support (3) has an installation groove (35), and an installation block (5) is fixed in the installation groove (35). The installation cavity (51) is set in the installation block (5). The top of the installation block (5) has a round hole (55) for the limit post (521) to pass through. The installation block (5) has a connecting hole (56) for the sealing block (531) to pass through. The connecting hole (56) is connected to the adjustment channel (23).

2. The hydraulic drilling fixture for a machining center according to claim 1, characterized in that, The inner wall of the adjusting ring (31) is provided with several vertical grooves (312), and the upper end of the vertical grooves (312) is connected to the lower end of the spiral groove (311).

3. A hydraulic drilling fixture for a machining center according to claim 2, characterized in that, The top of the positioning mandrel (11) has a frustum (111), and an expansion sleeve (64) is fitted on the frustum (111). The cylinder seat (1) is provided with a drive mechanism that drives the expansion sleeve (64) to rise and fall along the axial direction of the frustum (111), so that the expansion sleeve (64) expands or contracts radially. The cylinder seat (1) is provided with a third channel (24) and a fourth channel (25) for supplying oil to the drive mechanism. The cylinder seat (1) is provided with three corner cylinders (41) that are evenly spaced in a ring. The telescopic rod of the corner cylinder (41) is fixed with a clamping block (411).

4. A hydraulic drilling fixture for a machining center according to claim 3, characterized in that, The cylinder seat (1) is provided with an adjustment chamber (26), and the driving mechanism includes a piston block (6) slidably disposed in the adjustment chamber (26). The piston block (6) divides the adjustment chamber (26) into a first oil chamber (261) and a second oil chamber (262). The third channel (24) connects to the first oil chamber (261), and the fourth channel (25) connects to the second oil chamber (262). The positioning mandrel (11) has a sliding groove (112) at the bottom and a sliding hole (113) at the top that connects the sliding groove (112) and the through frustum (111). The upper end of the cylinder seat (1) has a connecting port (27) that connects the first oil chamber (261) and the sliding groove (112). The piston block (6) has a connecting block (61) fixed on top of it and embedded in the connecting port (27). The connecting block (61) is used to block the connection between the connecting port (27) and the first oil chamber (261). The connecting block (61) has a cylinder rod (62) and an adjusting rod (63) fixed on top of it in sequence. The cylinder rod (62) is embedded in the slide groove (112). The adjusting rod (63) extends to the outside of the slide hole (113) and is fixedly connected to the expansion sleeve (64).

5. A hydraulic drilling fixture for a machining center according to claim 4, characterized in that, The first channel (21), the second channel (22), the adjustment channel (23), the adjustment cavity (26), and the connection port (27) are all located inside the base (2); The first channel (21), the second channel (22) and the third channel (24) all extend outward and connect to the base plate (4). The base plate (4) is provided with a fifth channel (42) and three unlocking channels (43) that are respectively connected to the three corner cylinders (41). The fourth channel (25) is connected to the base plate (4) and is connected to the fifth channel (42). The three unlocking channels (43) are all connected to the fifth channel (42). The base plate (4) is also provided with three locking channels (44) that are respectively connected to the three corner cylinders (41). The base plate (4) is provided with a main channel (45). The three locking channels (44) are all connected to the main channel (45).

6. A hydraulic drilling fixture for a machining center according to claim 2, characterized in that, One end of the adjusting rod (71) is fixed with a steel ball positioning screw (711), one end of the steel ball positioning screw (711) is embedded in the spiral groove (311), and one end of the steel ball of the steel ball positioning screw (711) is in contact with the inner side wall of the spiral groove (311).

7. A hydraulic drilling fixture for a machining center according to claim 5, characterized in that, The inner wall of the adjusting ring (31) is fixed with several limiting rods (314) that are distributed in a ring at equal intervals. The outer wall of the backrest (3) is provided with several limiting grooves (34). One end of the limiting rod (314) is embedded in the corresponding limiting groove (34).

8. A hydraulic drilling fixture for a machining center according to claim 6, characterized in that, The first rack (52) has a first guide block (523) on both sides, and the mounting cavity (51) has a first guide groove (513) on both sides of the inner wall. The first guide block (523) slides into the corresponding first guide groove (513). The second rack (53) has a second guide block (532) on both sides, and the mounting cavity (51) has a second guide groove (514) on both sides of the inner wall. The second guide block (532) slides into the corresponding second guide groove (514).

9. A hydraulic drilling fixture for a machining center according to claim 8, characterized in that, The bottom wall of the mounting cavity (51) is fixed with a guide post (511), and the lower end of the first rack (52) has a circular groove (522) for the guide post (511) to be inserted. The spring (512) is sleeved on the guide post (511).

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