Polishing equipment and method for coil panel support
By using a polishing device driven by a servo motor and a micro motor, combined with lateral and radial adjustments, the problem of uneven polishing of the inner hole of the coil disc support was solved, achieving high-precision inner hole machining and assembly compatibility.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGRAO JIHUA IND CO LTD
- Filing Date
- 2026-03-23
- Publication Date
- 2026-05-15
AI Technical Summary
Existing technology makes it difficult to perform personalized inner hole polishing for coil holders of different specifications, resulting in uneven inner hole surface polishing and incomplete grinding of residual protrusions in injection holes, which affects assembly compatibility.
The polishing roller, driven by a servo motor and equipped with a micro motor, achieves adaptive adjustment and compound movement of the polishing roller through lateral and radial adjustment, fully covering the inner hole area, and combining conical and spherical structures to achieve differentiated polishing.
It achieves seamless circumferential grinding of the inner hole of the coil support and differentiates the elimination of residual protrusions in the injection hole, improving the accuracy of the inner hole and the adaptability of subsequent assembly.
Smart Images
Figure CN122033738A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of coil disc holder polishing technology, specifically to a polishing device and method for coil disc holders. Background Technology
[0002] As a core component of electromagnetic induction-related equipment, the machining accuracy of the coil support directly affects the assembly and performance of the equipment. The inner hole of the metal coil support is the core connecting part between the coil support and other components, undertaking the role of positioning and assembly connection. The surface accuracy of the inner hole directly determines the fit and stability of the overall assembly. Therefore, inner hole polishing is an essential process in the production and processing of the coil support. In the existing technology, special polishing equipment is often used to grind the inner hole of the coil support. The burrs on the inner hole surface are removed and the flatness is improved by rotating the polishing component, thereby meeting the basic processing requirements of the coil support.
[0003] Injection holes are pre-drilled during the machining of the inner hole of the coil holder. Different sizes of coil holders correspond to different inner hole diameters, and the injection volume also varies for different sizes of coil holders, resulting in different injection hole sizes. After molding, the height and size of the residual protrusions formed at the injection holes also vary accordingly. Faced with a variety of residual protrusions, conventional fluid polishing or single rotary polishing methods are difficult to achieve targeted polishing and cannot effectively eliminate residual protrusions formed by injection holes of different sizes. Furthermore, during polishing operations, the polishing position and movement trajectory are difficult to adapt to the actual specifications of the workpiece, making it difficult to perform differentiated polishing on the inner hole plane and the residual protrusions of injection holes of different sizes. This often results in uneven polishing of the inner hole plane and incomplete polishing of residual protrusions in injection holes, affecting the subsequent assembly compatibility of the coil holder.
[0004] To address the aforementioned issues, innovative design based on existing methods is urgently needed. Summary of the Invention
[0005] The purpose of this invention is to provide a polishing device and method for coil disk supports to solve the problems mentioned in the background art. The technical solution of this invention addresses the problem that the existing technical solutions are too simplistic and provides a solution that is significantly different from the existing technology.
[0006] To achieve the above objectives, the present invention provides the following technical solution: a polishing device and method for a coil support, comprising a base, a placement frame fixedly installed on the upper end of the base, cylinders fixedly installed on both sides of the placement frame, and positioning blocks fixedly connected to the output ends of the cylinders; A servo motor is fixedly installed on the upper end of the base, a baffle is fixedly connected to the top of the output end of the servo motor, and a horizontal distance adjustment component is provided on the outer wall of the output end of the servo motor. The lateral distance adjustment assembly includes a T-shaped rod slidably connected to the output end of a servo motor. A sleeve is fixedly connected to one side of the T-shaped rod, and a first spring is fixedly connected between the sleeve and the output end of the servo motor. The first spring is sleeved on the outer wall of the T-shaped rod. A lead screw is rotatably connected to one side of the lower end of the baffle. A transmission plate is slidably connected to the outer wall of the lead screw. The transmission plate is slidably connected to the output end of the servo motor. An extrusion plate is fixedly connected to the upper end of the transmission plate. The extrusion plate is in contact with the outer wall of the T-shaped rod. Polishing assembly, located at the center of the sleeve, is used to polish the inner hole of the coil support. A polishing adjustment component is located at the lower end of the mounting frame and is used to adjust the polishing components.
[0007] Preferably, the polishing assembly includes a polishing roller slidably connected to the center of the sleeve, and a micro motor is provided at the lower end of the polishing roller, with the output end of the micro motor fixedly connected to the lower end of the polishing roller.
[0008] Preferably, the baffle is fixedly connected to a symmetrically arranged guide rod corresponding to the micro motor, the micro motor is slidably connected to the guide rod, a symmetrically arranged second spring is fixedly connected between the micro motor and the baffle, and the second spring is correspondingly sleeved on the outer wall of the guide rod, and a roller is fixedly installed at the lower end of the micro motor.
[0009] Preferably, the polishing adjustment assembly includes a conical barrel fixedly connected to the lower end of the transmission plate. The polishing adjustment assembly also includes an extension frame at the lower end of the placement frame. A support frame is fixedly connected to one side of the lower end of the extension frame. An installation frame is fixedly installed at the lower end of the support frame. Symmetrically arranged extrusion blocks are fixedly connected to the upper end of the installation frame.
[0010] Preferably, the extension frame is slidably connected to the upper end of the support frame with symmetrically arranged adjusting rods. One end of the adjusting rod is rotatably connected to a limit plate. A third spring is fixedly connected between the limit plate and the extension frame. The other end of the adjusting rod is rotatably connected to a ball seat. A ball is hinged to one side of the ball seat, and the ball abuts against the outer wall of the cone.
[0011] Preferably, each of the adjusting rods is fixedly connected to an adjusting plate on the side that is far apart from each other, and each adjusting rod has a curved groove on its outer wall, and the extrusion block is movably engaged with the corresponding curved groove.
[0012] Preferably, the roller is made of rubber, the roller is positioned corresponding to the adjusting plate, and the lateral length of the adjusting plate is five times that of the roller.
[0013] Preferably, the method includes the following steps: S1: Place the coil support to be polished on the placement rack, and use the cylinder to drive the positioning block to position and clamp the coil support; S2: According to the inner diameter of the coil support, rotate the screw to adjust the position of the transmission plate and the extrusion plate. The extrusion plate extrudes the T-shaped rod to complete the lateral adjustment of the polishing roller. The transmission plate drives the cone barrel to move. The cone barrel abuts against the extrusion ball and the ball seat, pushing the adjusting rod to move laterally. The curved groove cooperates with the extrusion block to make the adjusting rod rotate. The two side adjusting plates form isosceles steps corresponding to the protrusion of the injection hole in the inner hole of the coil support. S3: Start the servo motor and micro motor. The servo motor drives the horizontal distance adjustment component and the polishing component to revolve together, and the micro motor drives the polishing roller to rotate. The roller slides up and down along the adjustment plate, and the polishing roller floats radially with the help of the second spring to polish the inner hole of the coil plate bracket and the residual protrusion of the injection hole.
[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses a rotating lead screw to move the transmission plate and the extrusion plate. The extrusion plate presses the T-shaped rod, which in turn moves the sleeve and polishing roller to adjust their lateral position. The polishing roller can be adjusted to fit the inner diameter of different coil support holes. Combined with the servo motor output driving the lateral distance adjustment component and the polishing component to revolve together, and the micro motor directly driving the polishing roller to rotate at high speed, this composite motion allows the polishing roller to perform circumferential grinding on the inner hole of the coil support without dead angles, fully covering all polishing areas of the inner hole. This solves the problems of the polishing component position being difficult to adapt to different inner hole diameters and the incomplete circumferential grinding coverage in existing polishing methods, effectively improving the overall surface accuracy of the inner hole.
[0015] 2. When adjusting the horizontal distance adjustment component, the transmission plate synchronously drives the cone barrel to move axially. The cone barrel squeezes the ball and the ball seat to push the adjustment rod to move laterally. The curved groove and the squeezing block cooperate to drive the adjustment rod to rotate. The larger the inner diameter of the coil plate bracket, the greater the lateral adjustment distance of the polishing roller, the greater the axial stroke of the cone barrel, and the greater the range of movement and rotation of the adjustment rod. The angle of the isosceles step formed by the two adjustment plates is also greater. During the polishing operation, the roller slides along the step of the adjustment plate. With the guidance of the guide rod and the elastic reset of the second spring, the polishing roller floats radially. The larger the inner diameter, the larger the corresponding injection hole protrusion size, and the greater the radial floating range of the polishing roller. Differentiated grinding is achieved to eliminate residual protrusions in the injection hole. This solves the problem of poor treatment and incomplete grinding of protrusions of different sizes in conventional grinding methods, ensures the machining accuracy of the inner hole, and improves the adaptability of subsequent assembly. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the coil disk support structure in the installation state of the present invention; Figure 2 This is a cross-sectional view of the placement rack and base of the present invention; Figure 3 This is a front view of the overall structure of the horizontal distance adjustment component and polishing component of the present invention; Figure 4 This is a partial front view of the horizontal distance adjustment component and polishing component of the present invention; Figure 5 This is a partial structural side view of the lateral distance adjustment component and polishing component of the present invention; Figure 6 A partial structural schematic diagram of the polishing adjustment component of this invention; Figure 7 For the present invention Figure 2 Enlarged view of the structure of region A.
[0017] In the diagram: 1. Base; 2. Placement rack; 3. Cylinder; 4. Positioning block; 5. Servo motor; 6. Baffle; 701. T-shaped rod; 702. Sleeve; 703. First spring; 704. Lead screw; 705. Transmission plate; 706. Extrusion plate; 801. Polishing roller; 802. Micro motor; 803. Guide rod; 804. Second spring; 805. Roller; 901. Conical barrel; 902. Extension frame; 903. Support frame; 904. Mounting frame; 905. Extrusion block; 906. Adjusting rod; 907. Limiting plate; 908. Third spring; 909. Ball seat; 910. Ball; 911. Adjusting plate; 912. Curved groove. Detailed Implementation
[0018] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.
[0019] Please see Figures 1-7 The present invention provides a technical solution: a polishing device and method for a coil support, comprising a base 1, a placement frame 2 fixedly installed on the upper end of the base 1, cylinders 3 fixedly installed on both sides of the placement frame 2, and positioning blocks 4 fixedly connected to the output ends of the cylinders 3.
[0020] In one embodiment of the present invention, a servo motor 5 is fixedly installed on the upper end of the base 1, a baffle 6 is fixedly connected to the top of the output end of the servo motor 5, and a horizontal distance adjustment component is provided on the outer wall of the output end of the servo motor 5; the horizontal distance adjustment component includes a T-shaped rod 701 slidably connected to the output end of the servo motor 5, a sleeve 702 is fixedly connected to one side of the T-shaped rod 701, a first spring 703 is fixedly connected between the sleeve 702 and the output end of the servo motor 5, and the first spring 703 is sleeved on the outer wall of the T-shaped rod 701, a lead screw 704 is rotatably connected to one side of the lower end of the baffle 6, a transmission plate 705 is slidably connected to the outer wall of the lead screw 704, the transmission plate 705 is slidably connected to the output end of the servo motor 5, and an extrusion plate 706 is fixedly connected to the upper end of the transmission plate 705, the extrusion plate 706 is in contact with the outer wall of the T-shaped rod 701; The first spring 703 can achieve elastic reset of the lateral position of the polishing roller 801. When the lead screw 704 needs to be adjusted in the opposite direction to adapt to the coil support with different aperture, the extrusion plate 706 releases the extrusion force on the T-shaped rod 701. The first spring 703 can quickly drive the T-shaped rod 701, sleeve 702 and polishing roller 801 to reset to the initial position, which facilitates the readjustment and positioning of the polishing roller 801.
[0021] In one embodiment of the present invention, a polishing assembly is disposed at the center of the sleeve 702 and is used to polish the inner hole of the coil support; a polishing adjustment assembly is disposed at the lower end of the placement frame 2 and is used to adjust the polishing assembly. The polishing assembly includes a polishing roller 801 slidably connected to the center of the sleeve 702, a micro motor 802 disposed at the lower end of the polishing roller 801, the output end of the micro motor 802 being fixedly connected to the lower end of the polishing roller 801, a baffle 6 being fixedly connected to a symmetrically arranged guide rod 803 corresponding to the micro motor 802, the micro motor 802 being slidably connected to the guide rod 803, a symmetrically arranged second spring 804 being fixedly connected between the micro motor 802 and the baffle 6, and the second spring 804 being sleeved on the outer wall of the guide rod 803, and a roller 805 being fixedly installed at the lower end of the micro motor 802. The guide rod 803 guides the sliding of the micro motor 802, ensuring that the polishing roller 801 always maintains a perpendicular angle to the inner hole when it floats radially, thus preventing the polishing roller 801 from tilting and causing excessive polishing of the inner hole in some areas.
[0022] In one embodiment of the present invention, the polishing adjustment assembly includes a conical barrel 901 fixedly connected to the lower end of the transmission plate 705. The polishing adjustment assembly also includes an extension frame 902 at the lower end of the placement frame 2. A support frame 903 is fixedly connected to one side of the lower end of the extension frame 902. A mounting frame 904 is fixedly installed at the lower end of the support frame 903. Symmetrically arranged pressing blocks 905 are fixedly connected to the upper end of the mounting frame 904. Symmetrically arranged adjusting rods 906 are slidably connected to the extension frame 902 near the upper end of the support frame 903. One end of each adjusting rod 906 is rotatably connected to a limiting plate 907. A third spring 908 is fixedly connected between 7 and the extension frame 902. The other end of the adjusting rod 906 is rotatably connected to a ball seat 909. A ball 910 is hinged to one side of the ball seat 909. The ball 910 abuts against the outer wall of the cone barrel 901. Adjusting plates 911 are fixedly connected to the opposite sides of the adjusting rods 906. Curved grooves 912 are opened on the outer wall of the adjusting rods 906. The extrusion block 905 is movably fitted with the corresponding curved groove 912. The roller 805 is made of rubber. The roller 805 corresponds to the position of the adjusting plate 911, and the lateral length of the adjusting plate 911 is five times that of the roller 805. The rolling contact between the ball 910 and the cone 901 converts the axial linear motion of the cone 901 into the lateral movement and rotation of the adjusting rod 906, reducing transmission friction and adjusting the rotation angle of the adjusting plate 911. This ensures that the polishing force of the polishing roller 801 on the protrusions on both sides of the injection hole remains consistent. At the same time, the third spring 908 can always reset the adjusting rod 906, improving the adaptability of the angle of the adjusting rod 906.
[0023] As one embodiment of the present invention, the method includes the following steps: S1: Place the coil support to be polished on the placement rack 2, and use the cylinder 3 to drive the positioning block 4 to position and clamp the coil support; S2: Based on the inner diameter of the coil support, rotate the lead screw 704 to adjust the position of the transmission plate 705 and the extrusion plate 706. The extrusion plate 706 extrudes the T-shaped rod 701 to complete the lateral adjustment of the polishing roller 801. The transmission plate 705 drives the cone barrel 901 to move. The cone barrel 901 abuts against the extrusion ball 910 and the ball seat 909, pushing the adjusting rod 906 to move laterally. The curved groove 912 cooperates with the extrusion block 905 to make the adjusting rod 906 rotate. The two side adjusting plates 911 form isosceles steps corresponding to the protrusion of the injection hole in the inner hole of the coil support. S3: Start the servo motor 5 and the micro motor 802. The servo motor 5 drives the horizontal distance adjustment component and the polishing component to revolve together. The micro motor 802 drives the polishing roller 801 to rotate. The roller 805 slides up and down along the adjustment plate 911. With the help of the second spring 804, the polishing roller 801 floats radially to polish the inner hole of the coil support and the residual protrusion of the injection hole.
[0024] Working principle: Before positioning, place the coil support to be polished on the placement rack 2, start the cylinder 3, the output end of the cylinder 3 extends outward and drives the positioning block 4 to move towards the coil support until the positioning block 4 is tightly attached to the outer wall of the coil support, thus completing the positioning and clamping of the coil support, preventing the support from shifting during the polishing process and ensuring polishing accuracy; After positioning, the horizontal distance is adjusted according to the inner diameter of the coil support. The lead screw 704 is rotated, which drives the transmission plate 705 to move upward along the output end of the servo motor 5. The transmission plate 705 simultaneously drives the extrusion plate 706 to move upward. The upward-moving extrusion plate 706 generates extrusion force on the end of the T-shaped rod 701. The T-shaped rod 701 is extruded, which in turn drives the sleeve 702 and the polishing assembly at the center of the sleeve 702 to move laterally until the lateral position of the polishing roller 801 matches the inner diameter of the coil support. The position of the polishing assembly is adjusted according to different inner hole sizes to adapt to the polishing operation of various specifications of coil supports. During the lateral distance adjustment, polishing adjustment is performed simultaneously. As the transmission plate 705 moves upward, it drives the cone barrel 901 to move upward simultaneously. The upward-moving cone barrel 901 generates a squeezing force on the ball 910. The ball 910 transmits the squeezing force to the ball seat 909, which in turn pushes the adjusting rod 906 to move laterally along the extension frame 902. During the movement of the adjusting rod 906, the curved groove 912 on its outer wall is squeezed by the squeezing block 905, causing the symmetrically arranged adjusting rod 906 to rotate. The rotation of the adjusting rod 906 drives the adjusting plate 911 to rotate synchronously until the two adjusting plates 911 form an isosceles step that matches the protrusion of the injection hole in the inner hole of the coil support. The greater the distance the cone barrel 901 moves upward, the greater the step angle formed by the adjusting plate 911. During polishing, servo motor 5 and micro motor 802 are started. After servo motor 5 starts, it drives the polishing assembly to repeatedly revolve around the output end of servo motor 5 via T-shaped rod 701 and sleeve 702, so that polishing roller 801 can cover the entire polishing area of the inner hole of coil disk support. After micro motor 802 starts, it directly drives polishing roller 801 to rotate at high speed. The revolving and rotating polishing roller 801 polishes the burrs in the inner hole of coil disk support. When micro motor 802 revolves with polishing assembly to the position of adjustment plate 911, the roller 805 at the lower end of micro motor 802 contacts adjustment plate 911. Under the pressure of the step of adjustment plate 911, micro motor 802... Sliding upward along the guide rod 803, the micro motor 802 synchronously drives the polishing roller 801 to move upward, further radially polishing the residual protrusions of the injection hole in the inner hole of the coil plate bracket; when the micro motor 802 disengages from the adjusting plate 911 as it revolves, the second spring 804 on the outer wall of the guide rod 803 releases its elastic potential energy, pushing the micro motor 802 to slide downward along the guide rod 803 to reset. At the same time, the micro motor 802 drives the polishing roller 801 to return to its initial position, continuing to polish the planar area of the inner hole of the bracket. This process is repeated to achieve the initial polishing of the planar surface of the inner hole of the coil plate bracket and further polishing the residual protrusions of the injection hole, improving the comprehensiveness and targeting of the polishing operation.
[0025] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.
Claims
1. A polishing device for a coil support, comprising a base (1), a placement frame (2) fixedly installed on the upper end of the base (1), cylinders (3) fixedly installed on both sides of the placement frame (2), and positioning blocks (4) fixedly connected to the output ends of the cylinders (3); Its features are: A servo motor (5) is fixedly installed on the upper end of the base (1), and a baffle (6) is fixedly connected to the top of the output end of the servo motor (5). A horizontal distance adjustment component is provided on the outer wall of the output end of the servo motor (5). The lateral distance adjustment assembly includes a T-shaped rod (701) slidably connected to the output end of a servo motor (5). A sleeve (702) is fixedly connected to one side of the T-shaped rod (701). A first spring (703) is fixedly connected between the sleeve (702) and the output end of the servo motor (5). The first spring (703) is sleeved on the outer wall of the T-shaped rod (701). A lead screw (704) is rotatably connected to one side of the lower end of the baffle (6). A transmission plate (705) is slidably connected to the outer wall of the lead screw (704). The transmission plate (705) is slidably connected to the output end of the servo motor (5). An extrusion plate (706) is fixedly connected to the upper end of the transmission plate (705). The extrusion plate (706) is in contact with the outer wall of the T-shaped rod (701). Polishing assembly, which is located at the center of sleeve (702), is used to polish the inner hole of coil support; Polishing adjustment component, which is located at the lower end of the placement frame (2), is used to adjust the polishing component.
2. The polishing equipment for a coil disk support according to claim 1, characterized in that: The polishing assembly includes a polishing roller (801) slidably connected to the center of the sleeve (702), and a micro motor (802) is provided at the lower end of the polishing roller (801). The output end of the micro motor (802) is fixedly connected to the lower end of the polishing roller (801).
3. The polishing equipment for a coil disk support according to claim 2, characterized in that: The baffle (6) is fixedly connected to the micro motor (802) with symmetrically arranged guide rods (803). The micro motor (802) is slidably connected to the guide rods (803). A second spring (804) is fixedly connected between the micro motor (802) and the baffle (6), and the second spring (804) is sleeved on the outer wall of the guide rod (803). A roller (805) is fixedly installed at the lower end of the micro motor (802).
4. The polishing equipment for a coil disk support according to claim 3, characterized in that: The polishing adjustment assembly includes a cone barrel (901) fixedly connected to the lower end of the transmission plate (705). The polishing adjustment assembly also includes an extension frame (902) at the lower end of the placement frame (2). A support frame (903) is fixedly connected to one side of the lower end of the extension frame (902). An installation frame (904) is fixedly installed at the lower end of the support frame (903). A symmetrically arranged extrusion blocks (905) are fixedly connected to the upper end of the installation frame (904).
5. The polishing equipment for a coil disk support according to claim 4, characterized in that: The extension frame (902) is slidably connected to the upper end of the support frame (903) with symmetrically arranged adjusting rods (906). One end of the adjusting rods (906) is rotatably connected to a limiting plate (907). A third spring (908) is fixedly connected between the limiting plate (907) and the extension frame (902). The other end of the adjusting rods (906) is rotatably connected to a ball seat (909). A ball (910) is hinged to one side of the ball seat (909). The ball (910) abuts against the outer wall of the cone (901).
6. The polishing equipment for a coil disk support according to claim 5, characterized in that: Each of the adjusting rods (906) has an adjusting plate (911) fixedly connected to the side of each rod that is far apart from the others. The outer wall of each adjusting rod (906) is provided with a curved groove (912). The pressing block (905) is movably fitted with the corresponding curved groove (912).
7. A polishing device for a coil disc support according to claim 6, characterized in that: The roller (805) is made of rubber. The roller (805) is positioned corresponding to the adjusting plate (911), and the horizontal length of the adjusting plate (911) is five times that of the roller (805).
8. A method of using a polishing device for a coil disc holder, applicable to the polishing device for a coil disc holder as described in any one of claims 1-7, characterized in that: The method includes the following steps: S1: Place the coil support to be polished on the placement rack (2), and use the cylinder (3) to drive the positioning block (4) to position and clamp the coil support; S2: According to the inner diameter of the coil support, rotate the screw (704) to adjust the position of the transmission plate (705) and the extrusion plate (706). The extrusion plate (706) extrudes the T-shaped rod (701) to complete the lateral adjustment of the polishing roller (801). The transmission plate (705) drives the cone barrel (901) to move. The cone barrel (901) abuts against the extrusion ball (910) and the ball seat (909), pushing the adjusting rod (906) to move laterally. The curved groove (912) cooperates with the extrusion block (905) to make the adjusting rod (906) rotate. The two side adjusting plates (911) form isosceles steps corresponding to the protrusion of the injection hole in the inner hole of the coil support. S3: Start the servo motor (5) and the micro motor (802). The servo motor (5) drives the horizontal distance adjustment component and the polishing component to revolve together. The micro motor (802) drives the polishing roller (801) to rotate. The roller (805) slides up and down along the adjustment plate (911). With the help of the second spring (804), the polishing roller (801) floats radially to polish the inner hole of the coil support and the residual protrusion of the injection hole.