Numerical control precision grinding device for assembling hole of automobile injection molding part

Abstract

The application belongs to the technical field of polishing devices for assembly holes of injection molded parts, in particular to a numerical control precision polishing device for assembly holes of automobile injection molded parts, which comprises a rack, the two sides of the top of the rack are fixedly connected with first linear modules, first sliding seats are arranged on the two first linear modules, and a second linear module is fixedly connected with the top of the two first sliding seats; in the application, the rigid support of the hollow top rod in the circumferential direction of the bottom of the assembly hole effectively offsets the downward pressure of the polishing rod, avoids the collapse of the orifice or the size deviation of the injection molded part due to stress deformation, significantly improves the machining precision and surface quality of the assembly hole, uses the inner cavity of the hollow top rod as a negative pressure suction channel, cooperates with the second suction hole and the round corner port of the spiral structure to generate rotating airflow, enhances the suction and carrying capacity of the grinding chips, realizes the timely and directional discharge of the grinding chips, avoids scratching the hole wall or interfering with the line of sight, and improves the cleanliness and safety of the polishing process.

Description

Technical Field

[0001] This invention belongs to the technical field of grinding devices for assembly holes of injection molded parts, specifically a CNC precision grinding device for assembly holes of automotive injection molded parts. Background Technology

[0002] Injection molding is a widely used process in manufacturing, especially in the production of plastic products. The basic process involves injecting heated and molten plastic material into a mold cavity. After it cools and solidifies, a finished product with the same shape as the cavity is obtained. In the automotive manufacturing industry, many structural parts are made using this process. However, after the injection molded parts are shaped and demolded, the edges of their assembly holes often have burrs of varying degrees. To ensure the assembly accuracy and overall quality of the parts, these burrs usually need to be finely trimmed using a grinding device to meet the stringent quality requirements of automotive parts.

[0003] Existing technologies disclose several invention patents in the field of grinding devices for injection molded parts assembly holes. Among them, patent CN120645064B discloses a precision grinding device for assembly holes in automotive injection molded parts, comprising: a grinding rod with a round rod fixedly mounted at its bottom end, a connecting disc rotatably mounted on its top end via a bearing, a driving mechanism above it for driving the grinding rod to rotate, two storage slots symmetrically opened on the outer peripheral wall of the round rod, each containing a grinding block slidably mounted, with both ends of one side of the grinding block being beveled, and two buffer mechanisms between them for injecting air into the storage slots respectively, and a monitoring machine. The first device, located below the drive mechanism, relates to the technical field of grinding devices for injection molded parts assembly holes. When in use, this improved grinding device can sequentially remove burrs from the inner ring edge or chamfered surface at the top of the assembly hole, the inner wall of the assembly hole, and the inner ring edge or chamfered surface at the bottom of the assembly hole through the rotation of the grinding rod. The burr removal effect on the assembly hole is good. However, the CNC precision grinding device for automotive injection molded parts assembly holes has a shortcoming: it easily causes structural damage to thin-walled holes. When the device drives the grinding rod for precision grinding, radial force and vibration are inevitably generated. When the hole wall thickness is insufficient to resist such dynamic loads, it will be damaged due to overload.

[0004] Based on this, the present invention designs a CNC precision grinding device for assembly holes of automotive injection molded parts to solve the above problems. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention proposes a CNC precision grinding device for assembly holes in automotive injection molded parts. This invention primarily addresses the limitation of existing CNC precision grinding devices for assembly holes in automotive injection molded parts, which are prone to causing structural damage to thin-walled holes. When this device drives the grinding rod for precision grinding, radial forces and vibrations are inevitably generated. When the hole wall thickness is insufficient to withstand such dynamic loads, it will be damaged due to overload.

[0006] The technical solution adopted by the present invention to solve its technical problem is: a CNC precision grinding device for assembly holes of automotive injection molded parts, comprising a frame, two first linear modules fixedly connected to the top of the frame on both sides, each of the two first linear modules being provided with a first slide, the top of the two first slides being fixedly connected to a second linear module, the second linear module being provided with a second slide, and a grinding machine being provided on the second slide; a pneumatic clamp is fixedly connected to the inner side wall of the frame and below the grinding machine, a grinding platform is suspended on the inner side of the pneumatic clamp, and multiple Z-shaped brackets are fixedly connected to the bottom of the grinding platform, the grinding platform being fixedly connected to the top of the pneumatic clamp through the multiple Z-shaped brackets;

[0007] The surface of the grinding platform, corresponding to the position of the grinding machine, has multiple chip removal ports. A fixed base is suspended below the grinding platform, corresponding to the position of the grinding machine. A flange is fixedly fitted onto the circumference of the fixed base, and a U-shaped frame is movably fitted onto the circumference of the fixed base. The top of the U-shaped frame is detachably connected to the bottom of the flange. A hollow push rod is fitted onto the inner wall of the fixed base, and the bottom end of the hollow push rod is connected to a first vacuum tube. A negative pressure fan is installed at the bottom of the inner side of the frame. The other end of the first vacuum tube is connected to the input port of the negative pressure fan. A first solenoid valve is installed on the first vacuum tube. The other end of the U-shaped frame is fixedly connected to the grinding machine so that the hollow push rod moves with the grinding machine. The fixed base also has a lifting assembly for adjusting the height of the hollow push rod.

[0008] Preferably, the lifting assembly includes multiple directional sleeves snapped onto the top of the fixed base, each directional sleeve having a directional shaft slidably fitted inside it, the top ends of the multiple directional shafts being fixedly connected to a movable base, and the hollow top rod being fixedly fitted onto the inner sidewall of the movable base;

[0009] A first adapter frame is fixedly connected to the circumferential surface of the movable seat. A first adapter joint is rotatably connected to the inner side of the first adapter frame. The other end of the first adapter joint is fixedly connected to the piston rod end of the hydraulic cylinder. A second adapter joint is fixedly connected to the cylinder body end of the hydraulic cylinder. A second adapter frame is fixedly connected to the circumferential surface of the fixed seat. The second adapter joint is rotatably connected to the inner side of the second adapter frame.

[0010] Preferably, the top of the hollow top rod is provided with a first annular groove, and the outer wall of the hollow top rod is provided with a suction hole corresponding to the position of the first annular groove. The suction hole is connected to a second vacuum tube, and the other end of the second vacuum tube is connected to the first vacuum tube. The connection node is located between the negative pressure fan and the first solenoid valve, and a second solenoid valve is provided on the second vacuum tube.

[0011] Preferably, the top of the hollow top rod is further provided with two second annular grooves, which are respectively located on the inner and outer sides of the first annular groove. A first sealing ring is slidably fitted in each second annular groove. A plurality of first stabilizing shafts arranged in a ring array are fixedly connected to the bottom of the first sealing ring. A first stabilizing groove is provided in the inner bottom of the second annular groove and at the position corresponding to each of the first stabilizing shafts. Each first stabilizing shaft is slidably fitted in the corresponding first stabilizing groove. A first spring is fitted on each first stabilizing shaft. The bottom of the first sealing ring is elastically supported by the inner bottom of the first stabilizing groove through the plurality of first springs.

[0012] Preferably, a piston ring is slidably sleeved in the first annular groove, and the piston ring is located below the suction hole. A third annular groove is formed on the outer circumferential surface of the piston ring. A second sealing ring is sleeved on the piston ring at a position corresponding to the second annular groove. A plurality of bridging shafts arranged in an annular array are fixedly connected to the top of the piston ring. An anti-slip disc is fixedly connected to the top of the plurality of bridging shafts. A plurality of first air holes are formed on the top of the anti-slip disc. A plurality of second air holes are formed on the outer annular surface of the anti-slip disc. The plurality of second air holes are respectively connected to the plurality of first air holes one by one.

[0013] Preferably, the bottom of the piston ring is fixedly connected to a plurality of second stabilizing shafts arranged in a ring array. The inner bottom of the first annular groove and the positions corresponding to the plurality of second stabilizing shafts are provided with a plurality of second stabilizing grooves. The plurality of second stabilizing shafts are slidably connected in the corresponding plurality of second stabilizing grooves. Each second stabilizing shaft is fitted with a second spring. The bottom of the piston ring is elastically supported by the plurality of second springs and the inner bottom of the second stabilizing groove.

[0014] Preferably, a fixing frame is fixedly sleeved on the inner side wall of the hollow top rod, a sleeve is provided on the fixing frame, a sleeve shaft is sleeved inside the top port of the sleeve, a fourth spring is fixedly connected to the bottom end of the sleeve shaft, the sleeve shaft and the inner bottom of the sleeve are elastically supported by the fourth spring, an inner liner is provided at the top end of the sleeve shaft, the inner liner is slidably sleeved on the inner side wall of the hollow top rod, and the outer diameter of the inner liner is equal to the inner diameter of the assembly hole, and a plurality of second suction holes arranged in a ring array are opened at the edge of the top of the inner liner.

[0015] Preferably, the top end of the sleeve shaft is provided with an adapter groove, and an adapter shaft is sleeved in the adapter groove. The top end of the adapter shaft is fixedly connected to the bottom end of the inner lining.

[0016] The inner wall of the adapter groove is provided with multiple grooves, and a graphite column is slidably fitted in each groove. One end of the graphite column abuts against the axial surface of the adapter shaft, and the other end of the graphite column is fixedly connected to a third spring. The graphite column and the inner wall of the groove are elastically supported by the third spring.

[0017] Preferably, a pressure sensor is provided between the fixing frame and the sleeve shaft;

[0018] The second suction hole is a spiral hole, and the top end of the second suction hole is provided with a rounded corner structure.

[0019] The beneficial effects of this invention are as follows:

[0020] 1. In this invention, the rigid support of the hollow push rod in the circumferential direction at the bottom of the assembly hole effectively counteracts the downward pressure of the grinding rod, preventing the injection molded part from cracking at the hole or dimensional deviation due to deformation under force. This significantly improves the machining accuracy and surface quality of the assembly hole. The hollow push rod cavity is used as a negative pressure suction channel, which, together with the spiral structure of the second suction hole and the rounded corner port, generates a rotating airflow, enhancing the ability to entrain and carry grinding chips. This enables timely and directional discharge of grinding chips, avoiding scratches on the hole wall or obstruction of vision, and improving the cleanliness and safety of the grinding process.

[0021] 2. In this invention, the two first sealing rings adopt independent elastic support, which can adaptively fit the bottom of the non-planar injection molded part to ensure effective sealing under irregular surfaces. The negative pressure drives the piston ring and the anti-slip disc to form a double locking effect of adsorption and pressing, which effectively prevents the injection molded part from shifting or vibrating during grinding, and improves processing stability. The inner liner, through the elastic support structure formed by the sleeve shaft and the fourth spring, can absorb the impact force and vibration energy generated by the grinding rod, which not only protects the injection molded part and the inner liner, but also improves the stability of the grinding process. At the same time, the first spring and the second spring provide buffering and reset functions during the movement of the first sealing ring, the second sealing ring and the piston ring to avoid rigid damage.

[0022] 3. In this invention, the graphite column is always in contact with the shaft surface of the adapter shaft under the elastic thrust of the third spring. Utilizing the self-lubricating properties of graphite, it provides continuous and uniform solid lubrication for the rotational fit between the adapter shaft and the adapter groove. It can also automatically compensate for wear, ensuring the durability and reliability of the lubrication effect. The pressure sensor collects the grinding pressure and its fluctuation data in real time, providing a basis for the system to dynamically adjust the feed speed or support force, forming a closed-loop control, avoiding deformation or insufficient processing due to improper pressure, and ensuring the stability and consistency of the processing process. Attached Figure Description

[0023] The invention will now be further described with reference to the accompanying drawings.

[0024] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 This is a cross-sectional structural schematic diagram of the present invention;

[0026] Figure 3 This is a schematic diagram of the hollow push rod in this invention;

[0027] Figure 4 In this invention Figure 3 A structural diagram from another perspective;

[0028] Figure 5 This is a schematic diagram of the structure of the inner liner in this invention;

[0029] Figure 6 In this invention Figure 5 A cross-sectional structural diagram;

[0030] Figure 7 This is the present invention. Figure 5 Schematic diagram of the structure after the hollow jacking rod has been removed;

[0031] Figure 8 In this invention Figure 7 A structural diagram from another perspective;

[0032] Figure 9 This is the present invention. Figure 2 Enlarged structural diagram at point A;

[0033] Figure 10 This is the present invention. Figure 3 Enlarged structural diagram at point B;

[0034] Figure 11 This is the present invention. Figure 6 Enlarged structural diagram at point C;

[0035] Figure 12 This is a schematic diagram of the structure of the sleeve shaft in this invention under cross-sectional view;

[0036] Figure 13 This is a frontal planar structural schematic diagram of the present invention.

[0037] In the diagram: 1. Frame; 2. First linear module; 3. First slide; 4. Second linear module; 5. Second slide; 6. Grinding machine; 7. Pneumatic clamp; 8. Grinding platform; 9. Chip discharge port; 10. U-shaped frame; 11. Fixed base; 12. Flange; 13. Orientation sleeve; 14. Orientation shaft; 15. Movable seat; 16. Hollow push rod; 17. First adapter frame; 18. First adapter joint; 19. Hydraulic cylinder; 20. Second adapter joint; 21. Second adapter frame; 22. First vacuum tube; 23. First solenoid valve; 24. Negative pressure fan; 25. First annular groove; 26. First suction hole; 27. Second vacuum tube; 28. Second solenoid valve; 29. 30. Second annular groove; 31. First sealing ring; 32. First stabilizing groove; 33. First stabilizing shaft; 34. First spring; 35. Piston ring; 36. Third annular groove; 37. Second sealing ring; 38. Second stabilizing groove; 39. Second stabilizing shaft; 40. Second spring; 41. Bridging shaft; 42. Anti-slip disc; 43. First vent; 44. Second vent; 45. Fixing bracket; 46. Pressure sensor; 47. Sleeve; 48. Sleeve shaft; 49. Adapter shaft; 50. Inner liner; 51. Second suction hole; 52. Rounded corner; 53. Groove; 54. Graphite column; 55. Third spring; 56. Z-shaped bracket; 57. Fourth spring; 58. Adapter groove. Detailed Implementation

[0038] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0039] like Figures 1 to 13 As shown, a CNC precision grinding device for assembly holes of automotive injection molded parts includes a frame 1. Two first linear modules 2 are fixedly connected to the top of the frame 1 on both sides. Each of the two first linear modules 2 is provided with a first slide block 3. The tops of the two first slide blocks 3 are jointly fixedly connected to a second linear module 4. A second slide block 5 is provided on the second linear module 4, and a grinding machine 6 is provided on the second slide block 5. A pneumatic clamp 7 is fixedly connected to the inner wall of the frame 1 and below the grinding machine 6. A grinding platform 8 is suspended inside the pneumatic clamp 7. Multiple Z-shaped brackets 55 are fixedly connected to the bottom of the grinding platform 8, and the grinding platform 8 is fixedly connected to the top of the pneumatic clamp 7 via the multiple Z-shaped brackets 55.

[0040] Multiple chip discharge ports 9 are provided on the surface of the grinding platform 8 and at the position corresponding to the grinding machine 6. A fixed seat 11 is suspended below the grinding platform 8 and at the position corresponding to the grinding machine 6. A flange 12 is fixedly sleeved on the circumferential surface of the fixed seat 11. A U-shaped frame 10 is also movably sleeved on the circumferential surface of the fixed seat 11. The top of the U-shaped frame 10 is detachably connected to the bottom of the flange 12. A hollow push rod 16 is sleeved on the inner side wall of the fixed seat 11. The bottom end of the hollow push rod 16 is connected to a first vacuum tube 22. A negative pressure fan 24 is provided at the bottom of the inner side of the frame 1. The other end of the first vacuum tube 22 is connected to the input port of the negative pressure fan 24. A first solenoid valve 23 is provided on the first vacuum tube 22. The other end of the U-shaped frame 10 is fixedly connected to the grinding machine 6 so that the hollow push rod 16 moves with the grinding machine 6. A lifting component for adjusting the height of the hollow push rod 16 is also provided on the fixed seat 11.

[0041] The lifting assembly includes multiple directional sleeves 13 snapped onto the top of the fixed base 11, each directional sleeve 13 having a directional shaft 14 slidably fitted inside it, the top ends of the multiple directional shafts 14 being fixedly connected to a movable base 15, and a hollow push rod 16 being fixedly fitted onto the inner side wall of the movable base 15.

[0042] A first adapter frame 17 is fixedly connected to the circumferential surface of the movable seat 15. A first adapter 18 is rotatably connected to the inner side of the first adapter frame 17. The other end of the first adapter 18 is fixedly connected to the piston rod end of the hydraulic cylinder 19. A second adapter 20 is fixedly connected to the cylinder body end of the hydraulic cylinder 19. A second adapter frame 21 is fixedly connected to the circumferential surface of the fixed seat 11. The second adapter 20 is rotatably connected to the inner side of the second adapter frame 21.

[0043] Specifically, in this embodiment: after placing the automotive injection molded part to be processed on the top of the grinding platform 8, the system controls the pneumatic clamp 7 to move, completing the clamping and fixing of the injection molded part. After fixing, the multiple assembly holes of the injection molded part are exposed above the multiple chip discharge ports 9. The system controls the first linear module 2 and the second linear module 4 to move together until the grinding rod of the grinding machine 6 moves directly above one of the assembly holes. During the movement, the two first linear modules 2 drive the two first slide blocks 3 to drive the second linear module 4 to move in the longitudinal direction. The second linear module 4 drives the second slide block 5 to drive the grinding machine 6 to move in the lateral direction. During the displacement, the grinding machine 6 is driven by the U-shaped frame 10 and the flange 12 on it. Before the grinding rod grinds the assembly hole, the system controls the hydraulic cylinder 19 to extend. The two ends of the hydraulic cylinder 19 rotate inside the first adapter 17 and the second adapter 21 respectively via the first adapter 18 and the second adapter 20, transmitting thrust to the movable seat 15. Under the thrust, the movable seat 15 drives multiple directional shafts 14 to slide upwards within the multiple directional sleeves 13, carrying the hollow ejector rod 16 upwards. The top of the hollow ejector rod 16 passes through the corresponding chip discharge port 9 and continues to rise until its top abuts against the bottom of the injection molded part. At this point, the inner diameter of the hollow ejector rod 16 is equal to the inner diameter of the assembly hole, thus forming a support in the circumferential direction corresponding to the assembly hole at the bottom of the injection molded part. The system supports the grinding machine 6 to counteract the downward pressure applied to the injection molded part by the grinding rod. Simultaneously, it controls the operation of the negative pressure fan 24, which has a filter at its inlet. When the system opens the first solenoid valve 23, the negative pressure fan 24 draws air from inside the hollow push rod 16 through the first vacuum tube 22, thus promptly removing grinding debris. By providing support in the circumferential direction corresponding to the injection molded part's bottom mounting hole, the system effectively counteracts the downward pressure applied by the grinding rod, preventing hole cracking or dimensional deviations caused by deformation during grinding. This ensures the machining accuracy and surface quality of the mounting hole. The hollow push rod 16's inner cavity serves as a suction channel, working in conjunction with the negative pressure fan. 24. Grinding chips are promptly and directionally removed, preventing them from accumulating in the assembly holes and scratching the hole walls or obstructing the grinding view, thus improving the cleanliness and safety of the grinding process. Through the coordinated linkage of the first linear module 2, the second linear module 4, and the hydraulic cylinder 19, the positioning of the grinding machine 6, the lifting and lowering of the hollow push rod 16, and the grinding action are automatically connected, reducing manual intervention and making it suitable for mass production CNC precision machining scenarios. The design of the U-shaped frame 10 and the flange 12 moving synchronously with the grinding machine 6 ensures the consistency of the horizontal position of the hollow push rod 16 and the grinding rod, reducing the error of repeated positioning. The sliding fit between the directional sleeve 13 and the directional shaft 14 ensures the linearity and stability of the lifting and lowering process of the hollow push rod 16.

[0044] Preferably, the top of the hollow push rod 16 is provided with a first annular groove 25, and the outer wall of the hollow push rod 16 is provided with a suction hole corresponding to the position of the first annular groove 25. The suction hole is connected to a second vacuum tube 27, and the other end of the second vacuum tube 27 is connected to the first vacuum tube 22. The connection node is located between the negative pressure fan 24 and the first solenoid valve 23. A second solenoid valve 28 is provided on the second vacuum tube 27.

[0045] The top of the hollow top rod 16 is also provided with two second annular grooves 29. The two second annular grooves 29 are respectively located on the inner and outer sides of the first annular groove 25. A first sealing ring 30 is slidably sleeved in each second annular groove 29. A plurality of first stabilizing shafts 32 arranged in an annular array are fixedly connected to the bottom of the first sealing ring 30. A first stabilizing groove 31 is provided in the inner bottom of the second annular groove 29 and at the position corresponding to each first stabilizing shaft 32. Each first stabilizing shaft 32 is slidably sleeved in the corresponding first stabilizing groove 31. A first spring 33 is sleeved on each first stabilizing shaft 32. The bottom of the first sealing ring 30 is elastically supported by the inner bottom of the first stabilizing groove 31 through the plurality of first springs 33.

[0046] Specifically, in this embodiment, the system controls the hydraulic cylinder 19 to drive the hollow push rod 16 upward. During this process, the top of the hollow push rod 16 abuts against the bottom of the injection molded part through two first sealing rings 30. After the tops of the two sealing rings contact the bottom of the injection molded part, the hollow push rod 16 continues to rise, and the two sealing rings retract into the two second annular grooves 29 respectively, and press down the first springs 33 connected to their bottoms respectively, causing the first springs 33 to undergo elastic deformation. Each first sealing ring 30 slides in the corresponding first stabilizing groove 31 through multiple first stabilizing shafts 32 connected to its bottom. When the bottom of the injection molded part is a non-planar structure, the compression of the two sealing rings is unequal to adapt to the contour of the bottom of the injection molded part. The system controls the first solenoid valve 23 to close and the second solenoid valve 28 to open, and starts the negative pressure fan 24. The negative pressure fan 24 draws air from the first annular groove 25 through the second vacuum tube 27 and suction hole, thereby forming a negative pressure adsorption at the bottom of the injection molded part. The two first sealing rings 30 are supported by independent elasticity. When the bottom of the injection molded part is not flat, each first sealing ring 30 can generate different compression amounts according to the local contour, adaptively fitting the bottom of the injection molded part, ensuring that an effective seal can still be formed on irregular surfaces, significantly improving the adaptability and reliability of negative pressure adsorption. The two first sealing rings 30 set on the inner and outer sides form an annular sealing barrier, effectively isolating external air from entering the first annular groove 25, ensuring the stability of the negative pressure adsorption force, and preventing adsorption failure due to air leakage. After contacting the injection molded part, the first sealing ring 30 continues to rise with the hollow push rod 16 and retracts into the second annular groove 29, avoiding damage to the first sealing ring 30 due to excessive compression. At the same time, the elastic support of the first spring 33 can buffer the impact force at the moment of contact, protecting the first sealing ring 30 and the bottom of the injection molded part from damage. The sliding cooperation between the first stabilizing shaft 32 and the first stabilizing groove 31 ensures that the movement trajectory of the first sealing ring 30 during the compression and retraction process is accurate and stable, avoiding the first sealing ring 30 from deflection or jamming, ensuring the consistency and long-term stability of the sealing effect.

[0047] Preferably, a piston ring 34 is slidably sleeved in the first annular groove 25, and the piston ring 34 is located below the suction hole. A third annular groove 35 is formed on the outer circumferential surface of the piston ring 34. A second sealing ring 36 is sleeved on the piston ring 34 at a position corresponding to the second annular groove 29. A plurality of bridging shafts 40 arranged in an annular array are fixedly connected to the top of the piston ring 34. An anti-slip disc 41 is fixedly connected to the top of the plurality of bridging shafts 40. A plurality of first air holes 42 are formed on the top of the anti-slip disc 41. A plurality of second air holes 43 are formed on the outer annular surface of the anti-slip disc 41. The plurality of second air holes 43 are respectively connected to the plurality of first air holes 42 one by one.

[0048] The bottom of the piston ring 34 is fixedly connected to a plurality of second stabilizing shafts 38 arranged in a ring array. The inner bottom of the first annular groove 25 and the positions corresponding to the plurality of second stabilizing shafts 38 are provided with a plurality of second stabilizing grooves 37. The plurality of second stabilizing shafts 38 are slidably connected in the corresponding plurality of second stabilizing grooves 37. A second spring 39 is sleeved on each of the second stabilizing shafts 38. The bottom of the piston ring 34 is elastically supported by the plurality of second springs 39 and the inner bottom of the second stabilizing groove 37.

[0049] Specifically, in this embodiment: the negative pressure fan 24 draws air from the first annular groove 25 through the second vacuum tube 27 and suction hole. As the pressure inside the first annular groove 25 decreases, the piston ring 34 drives the second sealing ring 36 to slide upward within the first annular groove 25. The bottom of the piston ring 34 slides in the corresponding second stabilizing grooves 37 through multiple second stabilizing shafts 38, and simultaneously pulls multiple second springs 39 to cause elastic deformation. The top of the piston ring 34 pushes the anti-slip disc 41 upward through multiple bridging shafts 40 until the top of the anti-slip disc 41 abuts against the bottom of the injection molded part. The top of the anti-slip disc 41 has multiple first air holes 42, and its outer ring surface has multiple second air holes 43, and the first air holes 42 and second air holes 43 are interconnected, so that the negative pressure suction is transmitted through the anti-slip disc 41 and acts on the area where the two sealing rings are located. The negative pressure drives the piston ring 34 to link with the anti-slip disc 41 to press against the bottom of the injection molded part upward, thereby increasing the suction power on the basis of the original negative pressure adsorption. The addition of mechanical auxiliary clamping creates a dual locking effect of adsorption and clamping, effectively preventing displacement or vibration of the injection molded part during grinding, significantly improving processing stability. The interconnected structure of the first air hole 42 and the second air hole 43 on the anti-slip disc 41 allows the negative pressure suction to be smoothly transmitted to the area where the two first sealing rings 30 are located, avoiding the attenuation of adsorption force due to the obstruction of the anti-slip disc 41, ensuring the smooth air path and adsorption effect of the entire negative pressure system. The second spring 39 provides elastic support and buffer during the sliding of the piston ring 34, which not only avoids rigid impact between the anti-slip disc 41 and the bottom of the injection molded part, causing damage, but also assists the piston ring 34 to automatically reset after the negative pressure is released, facilitating the picking and placing of the workpiece. The sliding cooperation between the second stabilizing shaft 38 and the second stabilizing groove 37 ensures that the piston ring 34 slides smoothly along the axial direction under the negative pressure drive, preventing skewing or jamming, ensuring the accuracy and consistency of the contact position between the anti-slip disc 41 and the bottom of the injection molded part, and improving the long-term operational reliability of the system.

[0050] Preferably, a fixing frame 44 is fixedly sleeved on the inner side wall of the hollow push rod 16, and a sleeve 46 is provided on the fixing frame 44. A sleeve shaft 47 is sleeved inside the top port of the sleeve 46. A fourth spring 56 is fixedly connected to the bottom end of the sleeve shaft 47. The sleeve shaft 47 and the inner bottom of the sleeve 46 are elastically supported by the fourth spring 56. An inner liner 49 is provided at the top end of the sleeve shaft 47. The inner liner 49 is slidably sleeved on the inner side wall of the hollow push rod 16, and the outer diameter of the inner liner 49 is equal to the inner diameter of the assembly hole. Multiple second suction holes 50 arranged in a ring array are opened at the edge of the top of the inner liner 49.

[0051] In this specific embodiment, during the process of the hollow push rod 16 being driven upward by the hydraulic cylinder 19, the hollow push rod 16 drives the inner liner 49 to rise synchronously through its internal fixing frame 44, so that the inner liner 49 passes through the corresponding chip discharge port 9 and enters the assembly hole. When the grinder 6 drives the grinding rod to grind the inner wall of the assembly hole, the bottom end of the grinding rod presses against the inner liner 49 and applies downward pressure to the inner liner 49. The inner liner 49 retracts inward along the port of the sleeve 46 through the sleeve shaft 47 and compresses the fourth spring 56 to produce elastic deformation. During the grinding process, the inner liner 49 forms radial support for the inner wall of the assembly hole. At the same time, the negative pressure inside the hollow push rod 16 acts on the bottom end of the grinding rod through multiple second suction holes 50, timely removing the grinding chips generated during grinding from the processing area. The inner liner 49 enters synchronously with the hollow push rod 16. Inside the assembly hole, radial support is formed on the inner wall of the assembly hole during the grinding process, effectively counteracting the radial force generated by the grinding rod, preventing the thin-walled injection molded parts from cracking or elastically deforming at the hole opening during grinding, and significantly improving the processing quality and dimensional accuracy of the assembly hole. The inner liner 49 forms an elastic support through the sleeve shaft 47 and the fourth spring 56. When the grinding rod applies pressure, the inner liner 49 can retract axially along the sleeve 46 to absorb and buffer the impact force and vibration energy during the grinding process, which not only protects the injection molded parts and the inner liner 49 itself from damage, but also improves the stability of the grinding process. The negative pressure inside the hollow push rod 16 acts on the bottom end of the grinding rod through the second suction hole 50, which promptly removes the grinding chips generated during grinding, avoiding the accumulation of grinding chips in the hole and scratching the processed surface or interfering with the grinding view, thus ensuring the smoothness of the processed surface.

[0052] Preferably, the top end of the sleeve shaft 47 is provided with a transition groove 57, and a transition shaft 48 is sleeved in the transition groove 57. The top end of the transition shaft 48 is fixedly connected to the bottom end of the inner liner 49.

[0053] The inner wall of the adapter groove 57 is provided with multiple grooves 52, and a graphite column 53 is slidably fitted in each groove 52. One end of the graphite column 53 abuts against the axial surface of the adapter shaft 48, and the other end of the graphite column 53 is fixedly connected to a third spring 54. The graphite column 53 forms an elastic support with the inner wall of the groove 52 through the third spring 54.

[0054] Specifically, in this embodiment: when the grinding rod grinds the inner wall of the assembly hole, the bottom end of the grinding rod abuts against the top of the inner liner 49. Under the torque transmitted by the grinding rod, the inner liner 49 rotates relative to the grinding rod within the transition groove 57 via the adapter shaft 48. Multiple grooves 52 are provided on the inner sidewall of the transition groove 57, and each groove 52 contains a graphite column 53. Under the elastic support of the third spring 54, the end of the graphite column 53 always remains abutting against the axial surface of the adapter shaft 48, providing continuous lubrication for the relative rotation between the adapter shaft 48 and the transition groove 57. Through the rotational cooperation between the adapter shaft 48 and the transition groove 57, the inner liner 49 can follow the grinding rod at a certain angle when the grinding rod applies torque. The rotating mechanism prevents localized wear or jamming of the inner liner 49 due to torsional stress, effectively protecting the inner liner 49 and the inner wall of the injection molding assembly hole from damage. The graphite column 53, under the elastic support of the third spring 54, always abuts against the axial surface of the adapter shaft 48. Utilizing the self-lubricating properties of graphite, it provides continuous and uniform solid lubrication to the rotating mating surface of the adapter shaft 48 and the adapter groove 57. The third spring 54 provides continuous elastic thrust to the graphite column 53. When the end of the graphite column 53 wears due to long-term use, the third spring 54 can automatically push the graphite column 53 forward to compensate, ensuring that the graphite column 53 always maintains tight contact with the axial surface of the adapter shaft 48, thus guaranteeing the durability and reliability of the lubrication effect.

[0055] Preferably, a pressure sensor 45 is provided between the fixing bracket 44 and the sleeve shaft 47;

[0056] The second suction hole 50 is a spiral hole, and a rounded corner 51 structure is provided at the top end of the second suction hole 50.

[0057] Specifically, in this embodiment, a pressure sensor 45 is disposed between the fixed frame 44 and the sleeve shaft 47 to monitor in real time the downward pressure and dynamic changes of the grinding rod acting on the inner liner 49. The second suction hole 50 is a spiral hole, and the top end of the second suction hole 50 is provided with a rounded corner structure 51. The pressure sensor 45 can collect the downward pressure and pressure fluctuation data of the grinding rod acting on the inner liner 49 in real time. The system can dynamically adjust the grinding feed speed or the support force of the hydraulic cylinder 19 accordingly to form a closed-loop control, avoiding deformation of the injection molded part due to excessive downward pressure or affecting the grinding effect due to insufficient pressure, effectively ensuring the stability and consistency of the processing process. The second suction hole 50 adopts a spiral structure, which generates a rotation effect when the airflow passes through, forming a spiral airflow, enhancing the carrying and entrainment capacity of grinding chips, and reducing the possibility of grinding chips remaining in the hole. The top end of the second suction hole 50 adopts a rounded corner structure 51.

[0058] During operation, after the automotive injection molded part to be processed is placed on the top of the grinding platform 8, the system controls the pneumatic clamp 7 to move and clamp and fix the injection molded part. After fixing, the multiple assembly holes of the injection molded part are exposed above each chip discharge port 9. The system controls the first linear module 2 and the second linear module 4 to move together, so that the grinding rod of the grinding machine 6 moves directly above the target assembly hole. During the movement, the two first linear modules 2 drive the second linear module 4 to move longitudinally by driving the first slide 3. The second linear module 4 drives the grinding machine 6 to move laterally by driving the second slide 5. At the same time, the grinding machine 6 drives the directional sleeve 13 to move synchronously through the U-shaped frame 10 and the flange 12 on it.

[0059] Before grinding, the system first controls the hydraulic cylinder 19 to extend. Its two ends rotate through the first adapter 18 and the second adapter 20 respectively inside the first adapter frame 17 and the second adapter frame 21, transmitting the thrust to the movable seat 15. Under the action of the thrust, the movable seat 15 drives multiple directional shafts 14 to slide upward in the corresponding directional sleeves 13, and carries the hollow push rod 16 upward. After the top of the hollow push rod 16 passes through the chip discharge port 9, it continues to rise until it abuts the bottom of the injection molded part. At this time, the inner diameter of the hollow push rod 16 is equal to the inner diameter of the assembly hole, thus forming a support in the circumferential direction of the corresponding assembly hole at the bottom of the injection molded part to counteract the downward pressure applied by the grinding rod. The system then starts the grinding machine 6 to grind, and at the same time controls the negative pressure fan 24 to run and opens the first solenoid valve 23 to draw air from the inside of the hollow push rod 16 through the first vacuum tube 22, so as to timely remove the grinding chips generated by grinding.

[0060] During this process, the top of the hollow push rod 16 abuts against the bottom of the injection molded part through two first sealing rings 30. After contact, the hollow push rod 16 continues to rise, and the two first sealing rings 30 retract into the corresponding second annular grooves 29 respectively, and press down the first spring 33 connected to the bottom, causing it to undergo elastic deformation. Each first sealing ring 30 slides in the corresponding first stabilizing groove 31 through multiple first stabilizing shafts 32 at its bottom. When the bottom of the injection molded part is not flat, the compression of the two first sealing rings 30 is different, adaptively conforming to the bottom contour. Subsequently, the system closes the first solenoid valve 23, opens the second solenoid valve 28, and starts the negative pressure fan 24, which draws air from the first annular groove 25 through the second vacuum tube 27 and suction hole, forming a negative pressure adsorption at the bottom of the injection molded part.

[0061] As the pressure in the first annular groove 25 decreases, the piston ring 34 drives the second sealing ring 36 to slide upward. Its bottom slides in the corresponding second stabilizing groove 37 through multiple second stabilizing shafts 38, and pulls multiple second springs 39 to produce elastic deformation. The top of the piston ring 34 pushes the anti-slip disc 41 upward through multiple bridging shafts 40 until its top abuts against the bottom of the injection molded part. The top of the anti-slip disc 41 is provided with multiple first air holes 42, and the outer ring surface is provided with multiple second air holes 43, and the two are interconnected, so that the negative pressure suction is transmitted through the anti-slip disc 41 and acts on the area where the two first sealing rings 30 are located.

[0062] When the hollow push rod 16 rises, its internal fixing frame 44 drives the inner liner 49 to rise synchronously, passing through the chip discharge port 9 and entering the assembly hole. When the grinding rod grinds the inner wall of the assembly hole, its bottom end presses against the inner liner 49, applying downward pressure. The inner liner 49 retracts inward along the sleeve 46 port through the sleeve shaft 47 and compresses the fourth spring 56 to produce elastic deformation, thereby forming radial support for the inner side wall of the assembly hole. At the same time, the negative pressure inside the hollow push rod 16 acts on the bottom end of the grinding rod through multiple second suction holes 50, which promptly removes the grinding chips.

[0063] During the grinding process, the bottom end of the grinding rod abuts against the top of the inner liner 49. Under the action of torque, the inner liner 49 rotates relative to the inner liner 49 in the transition groove 57 via the transition shaft 48. The inner sidewall of the transition groove 57 is provided with multiple grooves 52, and each groove 52 is provided with a graphite column 53. Under the elastic support of the third spring 54, the end of the column always abuts against the axial surface of the transition shaft 48, providing continuous lubrication for the rotation.

[0064] The pressure sensor 45 is located between the fixed frame 44 and the sleeve shaft 47 to monitor the downward pressure and dynamic changes of the grinding rod acting on the inner liner 49 in real time. The second suction hole 50 is a spiral hole with a rounded corner 51 structure at its top end.

[0065] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A CNC precision grinding device for assembly holes of automotive injection molded parts, comprising a frame (1), wherein first linear modules (2) are fixedly connected to both sides of the top of the frame (1), and first slides (3) are provided on both of the first linear modules (2), and a second linear module (4) is fixedly connected to the top of the two first slides (3), a second slide (5) is provided on the second linear module (4), and a grinding machine (6) is provided on the second slide (5); characterized in that: A pneumatic clamp (7) is fixedly connected to the inner wall of the frame (1) and below the grinder (6). A grinding platform (8) is suspended on the inner side of the pneumatic clamp (7). A plurality of Z-shaped brackets (55) are fixedly connected to the bottom of the grinding platform (8). The grinding platform (8) is fixedly connected to the top of the pneumatic clamp (7) through the plurality of Z-shaped brackets (55). Multiple chip discharge ports (9) are provided on the surface of the grinding platform (8) and at the position corresponding to the grinding machine (6). A fixed seat (11) is suspended below the grinding platform (8) and at the position corresponding to the grinding machine (6). A flange (12) is fixedly sleeved on the circumferential surface of the fixed seat (11). A U-shaped frame (10) is also movably sleeved on the circumferential surface of the fixed seat (11). The top of the U-shaped frame (10) is detachably connected to the bottom of the flange (12). A hollow top rod (16) is sleeved on the inner side wall of the fixed seat (11). The bottom end of the push rod (16) is connected to the first vacuum tube (22). A negative pressure fan (24) is provided at the bottom of the inner side of the frame (1). The other end of the first vacuum tube (22) is connected to the input port of the negative pressure fan (24). A first solenoid valve (23) is provided on the first vacuum tube (22). The other end of the U-shaped frame (10) is fixedly connected to the grinder (6) so that the hollow push rod (16) moves with the grinder (6). A lifting component for adjusting the height of the hollow push rod (16) is also provided on the fixed base (11).

2. The CNC precision grinding device for assembly holes of automotive injection molded parts according to claim 1, characterized in that: The lifting assembly includes multiple directional sleeves (13) snapped onto the top of the fixed base (11), each directional sleeve (13) having a directional shaft (14) slidably fitted inside it, the top ends of the multiple directional shafts (14) being fixedly connected to a movable base (15), and the hollow top rod (16) being fixedly fitted onto the inner side wall of the movable base (15). A first adapter (17) is fixedly connected to the circumferential surface of the movable seat (15). A first adapter (18) is rotatably connected to the inner side of the first adapter (17). The other end of the first adapter (18) is fixedly connected to the piston rod end of the hydraulic cylinder (19). A second adapter (20) is fixedly connected to the cylinder body end of the hydraulic cylinder (19). A second adapter (21) is fixedly connected to the circumferential surface of the fixed seat (11). The second adapter (20) is rotatably connected to the inner side of the second adapter (21).

3. The CNC precision grinding device for assembly holes of automotive injection molded parts according to claim 2, characterized in that: The top of the hollow top rod (16) is provided with a first annular groove (25). The outer wall of the hollow top rod (16) and the position corresponding to the first annular groove (25) are provided with a suction hole. The suction hole is connected to a second vacuum tube (27). The other end of the second vacuum tube (27) is connected to the first vacuum tube (22). The connection node is located between the negative pressure fan (24) and the first solenoid valve (23). A second solenoid valve (28) is provided on the second vacuum tube (27).

4. The CNC precision grinding device for assembly holes of automotive injection molded parts according to claim 3, characterized in that: The top of the hollow top rod (16) is also provided with two second annular grooves (29). The two second annular grooves (29) are respectively located on the inner and outer sides of the first annular groove (25). Each second annular groove (29) is slidably fitted with a first sealing ring (30). The bottom of the first sealing ring (30) is fixedly connected with a plurality of first stabilizing shafts (32) arranged in an annular array. The inner bottom of the second annular groove (29) and the position corresponding to each first stabilizing shaft (32) are respectively provided with a first stabilizing groove (31). Each first stabilizing shaft (32) is slidably fitted into the corresponding first stabilizing groove (31). Each first stabilizing shaft (32) is fitted with a first spring (33). The bottom of the first sealing ring (30) is elastically supported by the inner bottom of the first stabilizing groove (31) through the plurality of first springs (33).

5. A CNC precision grinding device for assembly holes of automotive injection molded parts according to claim 4, characterized in that: A piston ring (34) is slidably sleeved in the first annular groove (25), and the piston ring (34) is located below the suction hole. A third annular groove (35) is opened on the outer circumferential surface of the piston ring (34). A second sealing ring (36) is sleeved on the piston ring (34) and at the position corresponding to the second annular groove (29). A plurality of bridging shafts (40) arranged in an annular array are fixedly connected to the top of the piston ring (34). An anti-slip disc (41) is fixedly connected to the top of the plurality of bridging shafts (40). A plurality of first air holes (42) are opened on the top of the anti-slip disc (41). A plurality of second air holes (43) are opened on the outer annular surface of the anti-slip disc (41). The plurality of second air holes (43) are respectively connected to the plurality of first air holes (42).

6. A CNC precision grinding device for assembly holes of automotive injection molded parts according to claim 5, characterized in that: The bottom of the piston ring (34) is fixedly connected to a plurality of second stabilizing shafts (38) arranged in a ring array. The inner bottom of the first annular groove (25) and the position corresponding to the plurality of second stabilizing shafts (38) are provided with a plurality of second stabilizing grooves (37). The plurality of second stabilizing shafts (38) are slidably connected in the corresponding plurality of second stabilizing grooves (37). Each second stabilizing shaft (38) is fitted with a second spring (39). The bottom of the piston ring (34) is elastically supported by the plurality of second springs (39) and the inner bottom of the second stabilizing groove (37).

7. A CNC precision grinding device for assembly holes of automotive injection molded parts according to claim 6, characterized in that: A fixing frame (44) is fixedly sleeved on the inner side wall of the hollow top rod (16). A sleeve (46) is provided on the fixing frame (44). A sleeve shaft (47) is sleeved inside the top port of the sleeve (46). A fourth spring (56) is fixedly connected to the bottom end of the sleeve shaft (47). The sleeve shaft (47) forms an elastic support with the inner bottom of the sleeve (46) through the fourth spring (56). An inner liner (49) is provided at the top end of the sleeve shaft (47). The inner liner (49) is slidably sleeved on the inner side wall of the hollow top rod (16). The outer diameter of the inner liner (49) is equal to the inner diameter of the assembly hole. Multiple second suction holes (50) arranged in a ring array are opened at the edge of the top of the inner liner (49).

8. A CNC precision grinding device for assembly holes of automotive injection molded parts according to claim 7, characterized in that: The top end of the sleeve (47) is provided with a transition groove (57), and a transition shaft (48) is sleeved in the transition groove (57). The top of the transition shaft (48) is fixedly connected to the bottom of the inner lining (49). The inner wall of the adapter groove (57) is provided with a plurality of grooves (52), and a graphite column (53) is slidably fitted in each groove (52). One end of the graphite column (53) abuts against the axial surface of the adapter shaft (48), and the other end of the graphite column (53) is fixedly connected to a third spring (54). The graphite column (53) and the inner wall of the groove (52) are elastically supported by the third spring (54).

9. A CNC precision grinding device for assembly holes of automotive injection molded parts according to claim 8, characterized in that: A pressure sensor (45) is provided between the fixing frame (44) and the sleeve shaft (47). The second suction hole (50) is a spiral hole, and a rounded corner (51) structure is provided at the top port of the second suction hole (50).

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