A coil positioning device and method for solenoid gradient coils

Abstract

The application discloses a coil positioning device and a positioning method for a solenoid gradient coil, relates to the technical field of solenoids, and comprises an inner mold positioning assembly, a first positioning pin and a second positioning pin; the inner mold positioning assembly is embedded in a positioning hole of an inner mold; the first positioning pin is fixedly penetrated through the inner mold positioning assembly, one end of the first positioning pin is connected to a first side of the positioning hole, and the other end of the first positioning pin protrudes from a second side of the positioning hole; the second positioning pin is sleeved with the end portion of the first positioning pin located at the second side, and the second positioning pin is used for positioning a coil installed at the second side. The split positioning pin structure is adopted, so that the first positioning pin can be pre-installed during assembly, the second positioning pin serves as a positioning element directly contacting the coil, the second positioning pin can be reserved in the coil during demolding, the second positioning pin does not need to be taken out, and only the first positioning pin needs to be pulled out, so that the problem of insufficient operation space in a small hole diameter is solved, the demolding process is simplified, and the positioning precision and sealing reliability are improved.

Description

Technical Field

[0001] This invention relates to the field of solenoid technology, and in particular to a coil positioning device and positioning method for a solenoid gradient coil. Background Technology

[0002] In magnetic resonance imaging (MRI) systems, gradient coils are used to generate spatially encoded magnetic field gradients and are one of the core components. In small animal MRI equipment, solenoid gradient coils with small apertures (typically a few centimeters to tens of centimeters) are often used to obtain high-resolution images. Traditional solenoid gradient coil positioning devices typically use a single positioning pin fixed to an inner mold. The coil is fitted onto the inner mold, positioned using the positioning pin, then resin is poured in for curing, and finally the positioning pin is removed. This structure is suitable for gradient coils with larger inner diameters because the large inner diameter provides sufficient operating space for easy installation and removal of the positioning pin. However, for small-aperture solenoid gradient coils in small animal MRI equipment, the operating space is extremely limited, making the traditional single positioning pin structure difficult to implement. Installing and removing the positioning pin is challenging and can easily damage the coil or affect positioning accuracy.

[0003] Therefore, how to provide a positioning device suitable for small-aperture solenoid gradient coils is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to provide a coil positioning device for solenoid gradient coils, which is applicable to small-diameter solenoid gradient coils and facilitates the installation and removal of positioning pins.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A coil positioning device for a solenoid gradient coil, comprising: The inner mold positioning component is embedded in the positioning hole of the inner mold; The first positioning pin is fixedly inserted into the inner mold positioning assembly, with one end connected to the first side of the positioning hole and the other end protruding from the second side of the positioning hole. The second positioning pin is sleeved on the end of the first positioning pin located on the second side, and the second positioning pin is used to position the coil installed on the second side.

[0006] In one possible implementation, the inner mold positioning component includes: an inner mold positioning pin insert and an inner mold positioning pin inner insert, wherein the inner mold positioning pin insert is embedded in the positioning hole, the inner mold positioning pin inner insert is embedded in the inner mold positioning pin insert, and the first positioning pin passes through the inner mold positioning pin inner insert.

[0007] In one possible implementation, the inner mold positioning pin sleeve has a recessed groove at one end near the second side, and the inner mold positioning pin sleeve has a stepped protrusion that mates with the recessed groove at one end near the second side.

[0008] In one possible implementation, a sealing ring groove is provided on the end face of the inner mold positioning pin sleeve near the second side, and the sealing ring groove is coaxial with the inner mold positioning pin sleeve, and the sealing ring groove is used to install a sealing ring.

[0009] In one possible implementation, the first positioning pin includes a head, a body, and a tip connected in sequence, and the three are coaxially arranged. The body and the tip are distributed in a stepped manner, and the diameter of the tip is smaller than that of the body.

[0010] In one possible implementation, the second locating pin is provided with a first section hole and a second section hole that respectively mate with the main body and the tip. The first section hole is a locating pin hole, the tip is provided with an external thread, and the second section hole is provided with an internal thread that mates with the external thread.

[0011] In one possible implementation, the end head has a stepped structure, including a prism-shaped screwing section and a cylindrical connecting section, the connecting section being connected to the main body.

[0012] In one possible implementation, the second locating pin is made of epoxy resin.

[0013] In one possible implementation, the second locating pin abuts against the sealing ring.

[0014] The present invention also provides a coil positioning method for a solenoid gradient coil, based on the apparatus described above, comprising the following steps: Install the inner mold positioning component into the positioning hole of the inner mold; Pass the first positioning pin through the inner mold positioning assembly; The second positioning pin is fitted onto the end of the first positioning pin located on the second side; The gradient coil is sleeved over the second positioning pin to complete the positioning. After resin is poured between the inner mold and the outer shell, the first positioning pin is unscrewed, and demolding is completed.

[0015] Compared with the above-mentioned background technology, the present invention provides a coil positioning device for a solenoid gradient coil, comprising: an inner mold positioning component, a first positioning pin, and a second positioning pin; the inner mold positioning component is embedded in the positioning hole of the inner mold; the first positioning pin is fixedly inserted through the inner mold positioning component, with one end connected to the first side of the positioning hole and the other end protruding from the second side of the positioning hole; the second positioning pin is sleeved on the end of the first positioning pin located on the second side, and the second positioning pin is used to position the coil installed on the second side.

[0016] Specifically, the coil positioning device provided by the present invention adopts a split positioning pin structure. The first positioning pin is fixed to the inner mold positioning component, and the second positioning pin is sleeved on the end of the first positioning pin for positioning the coil. In this way, the first positioning pin can be pre-installed during assembly, and the second positioning pin, as a positioning element that directly contacts the coil, can remain inside the coil during demolding without needing to be removed. Only the first positioning pin needs to be pulled out, thereby solving the problem of insufficient operating space in small diameter holes, simplifying the demolding process, and improving positioning accuracy and sealing reliability. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the installation state structure of the positioning device provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the positioning device in use according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the positioning device structure provided in an embodiment of the present invention; Figure 4 This is an exploded view of the positioning device structure provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the positioning device provided in an embodiment of the present invention installed on the inner mold structure.

[0019] in: 100 - Inner mold, 110 - Positioning hole, 111 - First side, 112 - Second side, 120 - Outer shell; 200-First locating pin, 210-Screwing section, 211-Connecting section, 220-Main body, 230-Tip section; 300 - Second locating pin; 400-Inner mold locating pin insert; 500 - Inner mold positioning pin insert; 510 - Sealing ring groove; Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left" and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the position or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations of this invention.

[0023] The purpose of this invention is to provide a coil positioning device for solenoid gradient coils, which is applicable to small-diameter solenoid gradient coils and facilitates the installation and removal of positioning pins.

[0024] To achieve the above objectives, the present invention provides the following technical solution: Please see Figures 1 to 5 This embodiment provides a coil positioning device for a solenoid gradient coil, including: an inner mold positioning assembly, a first positioning pin 200, and a second positioning pin 300; the inner mold positioning assembly is embedded in the positioning hole 110 of the inner mold 100; the first positioning pin 200 is fixedly inserted into the inner mold positioning assembly, with one end connected to the first side 111 of the positioning hole 110 and the other end protruding from the second side 112 of the positioning hole 110; the second positioning pin 300 is sleeved on the end of the first positioning pin 200 located on the second side 112, and the second positioning pin 300 is used to position the coil installed on the second side 112.

[0025] Specifically, the inner mold 100 has a cylindrical structure, and a similarly cylindrical outer shell 120 is fitted around its outer periphery to form a mold. The gradient coil will be fixed in the annular space formed between the inner mold 100 and the outer shell 120. Resin is then poured into this space, and after it solidifies, demolding is performed. Understandably, the function of the first positioning pin 200 and the second positioning pin 300 is to fix the gradient coil in a preset position to prevent the coil from moving during resin pouring. Furthermore, during demolding, the first positioning pin 200 can be directly pulled out from the inside of the inner mold 100, while the second positioning pin 300 can remain inside the resin, thus reducing the difficulty of removing the first positioning pin 200 from the inside of the inner mold 100.

[0026] More specifically, in this embodiment, the first positioning pin 200 and the second positioning pin 300 can be combined into a complete positioning pin of a certain length. The inner mold positioning assembly provides an installation reference for the first positioning pin 200. During installation, one end of the first positioning pin 200 is connected to the first side 111 of the positioning hole 110, i.e., the inner side of the inner mold 100, while the other end protrudes partially from the second side 112 of the positioning hole 110, i.e., the outer side of the inner mold 100. The protruding part is used to connect to the second positioning pin 300. With the above structure, the first positioning pin 200 serves as the main positioning component, and the second positioning pin 300 serves as the positioning component that directly contacts the coil. The two can be separated. During assembly, the first positioning pin 200 is first fixed to the inner mold positioning assembly, then the second positioning pin 300 is fitted onto the end of the first positioning pin 200, and finally the coil is fitted onto the second positioning pin 300. After the resin has cured, only the first positioning pin 200 needs to be unscrewed, while the second positioning pin 300 remains inside the coil without needing to be removed. This avoids the coil damage that may be caused by the difficulty in removing a traditional single positioning pin, and is especially suitable for small-diameter coils with limited operating space.

[0027] In summary, the coil positioning device provided by this invention adopts a split positioning pin structure. The first positioning pin 200 is fixed to the inner mold positioning component, and the second positioning pin 300 is sleeved on the end of the first positioning pin 200 for positioning the coil. In this way, the first positioning pin 200 can be pre-installed during assembly, and the second positioning pin 300, as a positioning element that directly contacts the coil, can remain inside the coil during demolding without needing to be removed. Only the first positioning pin 200 needs to be pulled out, thereby solving the problem of insufficient operating space in small-diameter holes, simplifying the demolding process, and improving positioning accuracy and sealing reliability.

[0028] Furthermore, to provide a stable and reliable installation reference, the inner mold positioning assembly includes an inner mold positioning pin insert 400 and an inner mold positioning pin inner insert 500, specifically as follows: Figure 1 and Figure 2As shown. The inner mold locating pin sleeve 400 is embedded in the locating hole 110 and is usually made of metal, such as stainless steel. The inner mold locating pin sleeve 400 is tightly fitted with the inner mold 100 to enhance wear resistance. The inner mold locating pin inner sleeve 500 is embedded in the inner mold locating pin sleeve 400, and the first locating pin 200 passes through the inner mold locating pin inner sleeve 500. Through the double-layer sleeve structure, the positioning accuracy can be improved and the replacement of worn parts can be facilitated.

[0029] Understandably, the inner mold positioning pin insert 400 serves as an outer liner to protect the inner mold 100 body; the inner mold positioning pin insert 500 serves as an inner liner to directly cooperate with the first positioning pin 200. The two together form a high-precision guide hole to ensure the coaxiality and stability of the first positioning pin 200 installation, thereby ensuring the coil positioning accuracy.

[0030] To further improve the assembly stability and sealing of the inner mold positioning assembly, a countersunk groove is provided at the end of the inner mold positioning pin sleeve 400 near the second side 112, and a stepped protrusion that mates with the countersunk groove is provided at the end of the inner mold positioning pin inner sleeve 500 near the second side 112. The engagement of the countersunk groove and the stepped protrusion serves to axially position and limit movement, preventing axial movement of the inner mold positioning pin inner sleeve 500 under stress. This design, through mechanical fitting, enhances the connection strength between the inner mold positioning pin inner sleeve 500 and the inner mold positioning pin sleeve 400, avoids positioning errors caused by vibration, and improves the reliability of the device.

[0031] Considering the possibility of leakage during resin injection, this invention provides a sealing ring groove 510 on the end face of the inner mold positioning pin inner sleeve 500 near the second side 112. The sealing ring groove 510 is coaxial with the inner mold positioning pin inner sleeve 500 and is used to install a sealing ring. The sealing ring is preferably an O-ring, which is installed in the sealing ring groove 510. When the second positioning pin 300 is fitted onto the first positioning pin 200, the end face of the second positioning pin 300 abuts against the sealing ring, thereby sealing the gap between the first positioning pin 200 and the inner mold positioning assembly, preventing resin seepage. In this way, liquid resin can be effectively prevented from flowing into the inner mold 100 along the gap between the first positioning pin 200 and the inner mold positioning pin inner sleeve 500 during resin injection, ensuring smooth demolding and cleanliness inside the inner mold 100.

[0032] The specific structure of the first locating pin 200 is as follows: Figure 3 and Figure 4As shown, it includes a head portion, a main body portion 220, and a tip portion 230 connected in sequence, all three coaxially arranged. The main body portion 220 and the tip portion 230 are arranged in a stepped shape, with the tip portion 230 having a smaller diameter than the main body portion 220. The main body portion 220 is used to mate with the inner sleeve 500 of the inner mold positioning pin to achieve radial positioning; the tip portion 230 is used to connect with the second positioning pin 300. The stepped design provides a clear axial limit for the first positioning pin 200 during installation, and the end face of the main body portion 220 can abut against the end face of the inner sleeve 500 of the inner mold positioning pin, ensuring axial positioning accuracy. Through the stepped shaft structure, integrated machining is achieved, simplifying the assembly steps, while ensuring the coaxiality between the segments, thereby ensuring the positioning accuracy of the second positioning pin 300.

[0033] To achieve a detachable connection between the first positioning pin 200 and the second positioning pin 300, the second positioning pin 300 is provided with a first section hole and a second section hole that respectively mate with the main body 220 and the tip 230. The first section hole is a positioning pin hole, which has a clearance fit or transition fit with the main body 220 for radial positioning. The tip 230 is provided with an external thread, and the second section hole is provided with an internal thread that mates with the external thread. During assembly, the second positioning pin 300 is fitted onto the tip 230 of the first positioning pin 200, and the threads are tightened to achieve a fixed connection between the two. When separation is required, the first positioning pin 200 is rotated in the opposite direction to unscrew it, while the second positioning pin 300 remains in the coil. The threaded connection is reliable, facilitating assembly and disassembly. At the same time, the fit of the first section hole ensures the concentricity of the second positioning pin 300 and the first positioning pin 200, thereby ensuring the positioning accuracy of the coil.

[0034] To facilitate the operator in turning the first positioning pin 200, the end head has a stepped structure, which includes a prism-shaped screwing section 210 and a cylindrical connecting section 211, which is connected to the main body 220.

[0035] Understandably, the screwing section 210 can be hexagonal or square-headed, facilitating the application of torque using a wrench or socket tool; the connecting section 211 serves as a transition section, connecting to the main body 220. The screwing section 210 provides a standard tool interface, allowing for easy screwing in or out of the first locating pin 200 even in confined spaces, reducing operational difficulty and improving work efficiency.

[0036] Considering that the second positioning pin 300 needs to be permanently retained inside the coil, its material should possess characteristics such as non-magnetic properties, insulation, and good compatibility with resin. Therefore, in this embodiment, the second positioning pin 300 is preferably made of epoxy resin. Epoxy resin has good mechanical strength and electrical insulation properties, and good compatibility with the potting resin. It will not affect the uniformity of the magnetic field, nor will it affect the quality of MRI imaging. At the same time, it bonds well with the coil potting resin, and will not generate interface stress or detachment.

[0037] In one possible implementation, the second locating pin 300 abuts against the sealing ring. In the assembled state, the end face of the second locating pin 300 abuts against the sealing ring; that is, after the second locating pin 300 is fitted onto the first locating pin 200 and tightened, its end face presses against the sealing ring, achieving axial sealing. Directly pressing the sealing ring against the end face of the second locating pin 300 ensures reliable sealing, eliminates the need for additional clamping elements, and simplifies the structure.

[0038] The present invention also provides a method for positioning a coil in a solenoid gradient coil, based on the apparatus described above, comprising the following steps: Install the inner mold positioning component into the positioning hole 110 of the inner mold 100; specifically, first press the inner mold positioning pin sleeve 400 into the positioning hole 110, and then press the inner mold positioning pin inner sleeve 500 into the inner mold positioning pin sleeve 400 to ensure that the step protrusion and the groove are properly matched.

[0039] The first positioning pin 200 is passed through the inner mold positioning assembly; specifically, the main body 220 of the first positioning pin 200 is inserted into the inner mold positioning pin sleeve 500, so that its tip 230 protrudes from the second side 112.

[0040] The second positioning pin 300 is fitted onto the end of the first positioning pin 200 located on the second side 112; specifically, the sealing ring is placed into the sealing ring groove 510, and then the first section hole of the second positioning pin 300 is aligned with the main body 220, while the internal and external threads are tightened to press the end face of the second positioning pin 300 against the sealing ring.

[0041] The gradient coil is sleeved on the outside of the second positioning pin 300 to complete the positioning; specifically, the inner wall of the coil is tightly fitted with the outer cylindrical surface of the second positioning pin 300 to achieve precise radial positioning.

[0042] After resin is poured between the inner mold 100 and the outer shell 120, the first positioning pin 200 is unscrewed, and demolding is completed. Specifically, after the resin has cured, a wrench is used to hold the screwing section 210, and the first positioning pin 200 is rotated in the opposite direction to unscrew it from the inner mold positioning assembly. Since the second positioning pin 300 may remain fixed to the coil due to resin adhesion or interference, the first positioning pin 200 and the second positioning pin 300 are separated. Then, the coil assembly with the second positioning pin 300 is removed from the inner mold 100 as a whole, finally obtaining the finished gradient coil with the second positioning pin 300 embedded inside.

[0043] This method fully utilizes the characteristics of split positioning pins, achieving precise positioning and easy demolding within a small aperture, avoiding the difficulty of completely removing a traditional single positioning pin, and improving production efficiency and yield.

[0044] In summary, the coil positioning device and method for solenoid gradient coils provided by the present invention, by setting an inner mold positioning component, a first positioning pin 200 and a second positioning pin 300, achieves reliable positioning in small-aperture solenoid gradient coils, simplifies the demolding process, and ensures positioning accuracy and sealing performance.

[0045] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0046] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0047] The embodiments provided by the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A coil positioning device for a solenoid gradient coil, characterized in that, include: An inner mold positioning component is embedded in the positioning hole (110) of the inner mold (100); The first positioning pin (200) is fixedly inserted into the inner mold positioning assembly, with one end connected to the first side (111) of the positioning hole (110) and the other end protruding from the second side (112) of the positioning hole (110). The second positioning pin (300) is sleeved on the end of the first positioning pin (200) located on the second side (112), and the second positioning pin (300) is used to position the coil installed on the second side (112).

2. The coil positioning device for a solenoid gradient coil according to claim 1, characterized in that, The inner mold positioning component includes: an inner mold positioning pin sleeve (400) and an inner mold positioning pin inner sleeve (500). The inner mold positioning pin sleeve (400) is embedded in the positioning hole (110), and the inner mold positioning pin inner sleeve (500) is embedded in the inner mold positioning pin sleeve (400). The first positioning pin (200) passes through the inner mold positioning pin inner sleeve (500).

3. The coil positioning device for a solenoid gradient coil according to claim 2, characterized in that, The inner mold positioning pin sleeve (400) has a recessed groove at one end near the second side (112), and the inner mold positioning pin inner sleeve (500) has a stepped protrusion that cooperates with the recessed groove at one end near the second side (112).

4. The coil positioning device for a solenoid gradient coil according to claim 2, characterized in that, The inner mold positioning pin insert (500) has a sealing ring groove (510) on its end face near the second side (112), and the sealing ring groove (510) is coaxial with the inner mold positioning pin insert (500). The sealing ring groove (510) is used to install a sealing ring.

5. The coil positioning device for a solenoid gradient coil according to claim 1, characterized in that, The first positioning pin (200) includes a head, a body (220) and a tip (230) connected in sequence, and the three are coaxially arranged. The body (220) and the tip (230) are distributed in a stepped manner, and the diameter of the tip (230) is smaller than that of the body (220).

6. The coil positioning device for a solenoid gradient coil according to claim 5, characterized in that, The second positioning pin (300) is provided with a first section hole and a second section hole that respectively cooperate with the main body (220) and the tip (230). The first section hole is a positioning pin hole, the tip (230) is provided with an external thread, and the second section hole is provided with an internal thread that cooperates with the external thread.

7. The coil positioning device for a solenoid gradient coil according to claim 6, characterized in that, The end head has a stepped structure, including a prism-shaped screw section (210) and a cylindrical connecting section (211), which is connected to the main body (220).

8. The coil positioning device for a solenoid gradient coil according to claim 1, characterized in that, The second positioning pin (300) is made of epoxy resin.

9. The coil positioning device for a solenoid gradient coil according to claim 4, characterized in that, The second locating pin (300) abuts against the sealing ring.

10. A method for positioning a coil in a solenoid gradient coil, based on the apparatus according to any one of claims 1 to 9, characterized in that, Includes the following steps: The inner mold positioning component is installed in the positioning hole (110) of the inner mold (100); The first locating pin (200) is passed through the inner mold locating assembly; The second positioning pin (300) is fitted onto the end of the first positioning pin (200) located on the second side (112); The gradient coil is sleeved outside the second positioning pin (300) to complete the positioning; After resin is injected between the inner mold (100) and the outer shell (120), the first positioning pin (200) is unscrewed, and demolding is completed.

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