Linear variable differential transformer and hydraulic valve

Abstract

The utility model provides a linear variable differential transformer (LVDT). The LVDT comprises a pressure pipe, a coil assembly, a ferromagnetic core, an axial limiting device and an anti-rotation device. The ferromagnetic core is fixedly connected with a valve element of the hydraulic valve to detect the displacement of the valve element. The pressure pipe is fixed in a through hole in a plug of the hydraulic valve, so that an inner channel of the pressure pipe is aligned and communicated with a valve element channel of the hydraulic valve. The ferromagnetic core is located in the inner channel of the pressure pipe and is in linkage with a valve element of the hydraulic valve. The coil assembly is arranged outside the pressure pipe in a sleeving mode, is limited by the axial limiting device to move in the axial direction and is prevented from rotating in the circumferential direction by the anti-rotating device. The axial limiting device comprises a fixer which abuts against the outer end of the coil assembly and is fixed to the pressure pipe and an elastic deformation device which abuts against the position between the coil assembly and the plug. The elastic deformation device is matched with the fixing device so as to limit the axial position of the coil assembly on the pressure pipe. The utility model further provides a hydraulic valve comprising the LVDT. The utility model is convenient to install and can buffer vibration.

Description

Technical Field

[0001] The utility model relates to an electrical sensor and a valve comprising the electrical sensor, in particular to a linear variable differential transformer and a hydraulic valve comprising the linear variable differential transformer. Background Art

[0002] Linear Variable Differential Transformer (LVDT) is an electrical sensor that uses electromagnetic principles to measure linear displacement and converts the displacement into an electrical signal output. It is also called an LVDT sensor. Due to the non-contact measurement method of the linear variable differential transformer, it can provide accurate and reliable measurement results in various industrial environments, especially in hydraulic systems for monitoring the position of the valve core. Therefore, the linear variable differential transformer is a key component in hydraulic valves. The linear variable differential transformer can detect the displacement of the valve core of the hydraulic valve and convert the displacement signal into an electrical signal. Therefore, the accuracy and reliability of the linear variable differential transformer have a huge impact on the performance of the valve and directly affect the accuracy and reliability of the valve operation.

[0003] In addition, reliable assembly and component positioning of the LVDT is also critical to maintaining its performance and accurate signal conversion. Any improper assembly or misalignment may affect the stability of its performance.

[0004] In existing hydraulic valves, the coil assembly of the LVDT sensor usually has one end directly placed on the valve body, and the other end is fixed to the pressure pipe by tightening a nut. The LVDT sensor of the existing hydraulic valve is inconvenient to disassemble and assemble, and the accuracy is difficult to ensure. In the presence of vibration, the measurement accuracy is even more difficult to ensure.

[0005] Therefore, the art needs a linear variable differential transformer that is easy to assemble and disassemble and also needs a hydraulic valve that can ensure long-term stable performance. Utility Model Content

[0006] The technical problem to be solved by the utility model is to simplify the disassembly and assembly of the linear variable differential transformer to the hydraulic valve, and to improve the accuracy and reliability of the hydraulic valve.

[0007] In order to solve the above technical problems, the utility model provides a linear variable differential transformer for a hydraulic valve. The linear variable differential transformer includes a pressure tube, a coil assembly, a ferromagnetic core, an axial limit device and an anti-rotation device. The ferromagnetic core of the linear variable differential transformer is fixedly connected to the valve core of the hydraulic valve to detect the displacement of the valve core. The pressure tube is fixedly installed in the through hole on the plug of the hydraulic valve so that the inner channel of the pressure tube is aligned with and communicated with the valve core channel of the hydraulic valve. The ferromagnetic core is located in the inner channel of the pressure tube and is linked to the valve core of the hydraulic valve. The coil assembly is guided by the pressure tube and is sleeved on the outside of the pressure tube. The coil assembly is limited to move axially by the axial limit device and prevented from rotating circumferentially by the anti-rotation device. The axial limit device includes: a fixer that abuts against the outer end of the coil assembly and is fixedly engaged with the pressure tube; and an elastic deformation device that abuts between the inner end of the coil assembly and the plug. The elastic deformation device cooperates with the fixture to limit the axial position of the coil assembly on the pressure tube.

[0008] According to a preferred embodiment of the utility model, the elastic deformation device is a compression spring or a washer.

[0009] According to a preferred embodiment of the present invention, the fixer is a clamping ring or a locking nut.

[0010] According to a preferred embodiment of the present utility model, the anti-rotation device is a shape-fitting structure between the inner end of the coil assembly and the plug.

[0011] According to a preferred embodiment of the utility model, the shape-fitting structure includes an inner end portion of a non-circular cross-section of the coil assembly, and the inner end portion of the non-circular cross-section is accommodated in a shape-fitting groove formed on the plug to prevent the coil assembly from rotating.

[0012] According to a preferred embodiment of the present utility model, the non-circular cross section is a polygonal cross section, a toothed cross section and a combination thereof.

[0013] In order to solve the above technical problems, the present application also provides a hydraulic valve. The hydraulic valve includes a valve body, a valve core, a plug with a through hole and the above-mentioned linear variable differential transformer. The linear variable differential transformer includes a pressure tube, a coil assembly, a ferromagnetic core, an axial limit device and an anti-rotation device. The valve core of the hydraulic valve is fixedly connected to the ferromagnetic core of the linear variable differential transformer so as to detect the displacement of the valve core through the linear variable differential transformer. The pressure tube is fixedly installed on the through hole of the plug so that the valve core channel of the hydraulic valve is aligned with and communicated with the inner channel of the pressure tube. The valve core of the hydraulic valve is linked to the ferromagnetic core. The pressure tube guides the coil assembly and the coil assembly is sleeved on the outside of the pressure tube, and the coil assembly is limited to move axially by the axial limit device and prevented from rotating circumferentially by the anti-rotation device. The anti-rotation device is a shape-matching structure between the inner end of the coil assembly and the plug.

[0014] According to a preferred embodiment of the utility model, the shape-fitting structure includes an inner end portion of a non-circular cross-section of the coil assembly and a groove of a non-circular cross-section formed on the plug, wherein the non-circular cross-section of the inner end portion is complementary to the non-circular cross-section of the groove to prevent rotation of the coil assembly.

[0015] According to a preferred embodiment of the present utility model, the non-circular cross section is a polygonal cross section, a toothed cross section and a combination thereof.

[0016] According to a preferred embodiment of the present invention, the plug is a screw plug.

[0017] By adopting the technical solution of the utility model, the LVDT sensor can be easily assembled on the hydraulic valve, and the accuracy and performance stability of the hydraulic valve can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to enable those skilled in the art to more fully understand the present invention, the specific implementation of the present invention will be described in detail below in conjunction with the accompanying drawings.

[0019] Figure 1 It is a side view of a linear variable differential transformer for a hydraulic valve according to an embodiment of the utility model.

[0020] Figure 2 yes Figure 1 An enlarged cross-sectional view of the linear variable differential transformer is shown.

[0021] Figure 3 It is a side view of a hydraulic valve according to an embodiment of the utility model.

[0022] Figure 4It is a stereoscopic diagram of a coil assembly of an embodiment of the linear variable differential transformer of the present utility model.

[0023] Figure 5 For Figure 4 A three-dimensional view of a plug of a hydraulic valve to which the coil assembly is adapted;

[0024] Figure 6 It is a three-dimensional diagram of a coil assembly of another embodiment of the linear variable differential transformer of the present invention. DETAILED DESCRIPTION

[0025] In order to make the present invention clearer, a specific embodiment of the present invention is described in detail below with reference to the accompanying drawings, but the present invention is not limited to this embodiment.

[0026] Figure 1 to Figure 2 They are respectively a side view and an enlarged cross-sectional view of a linear variable differential transformer 1 of the utility model. As shown in the figure, the linear variable differential transformer 1 is installed on the hydraulic valve 2 to measure the linear displacement of the valve core 21 of the hydraulic valve 2. The linear variable differential transformer 1 includes a pressure tube 11, a coil assembly 12, a ferromagnetic core 13, an axial limit device and an anti-rotation device. The ferromagnetic core 12 of the linear variable differential transformer 1 is fixedly connected to the valve core 21 of the hydraulic valve 2 to detect the displacement of the valve core 21.

[0027] The pressure tube 11 is fixedly mounted on the through hole (222) of the plug 22 of the hydraulic valve 2, so that the inner channel of the pressure tube 11 is aligned with and communicated with the valve core channel of the hydraulic valve 2. The ferromagnetic core 13 is located in the inner channel of the pressure tube 11 and is connected to the valve core 21 of the hydraulic valve 2 to move linearly with the valve core 21, so that the displacement of the valve core 21 can be accurately detected.

[0028] The coil assembly 12 of the linear variable differential transformer 1 is guided by the pressure tube 11 and sleeved on the outside of the pressure tube 11, and is limited to a predetermined position on the pressure tube 11 as required. According to the utility model, the coil assembly 12 is limited in axial movement by an axial limiting device and is prevented from rotating in the circumferential direction by an anti-rotation device, so that the position of the coil assembly 12 on the pressure tube 11 can be ensured, thereby ensuring the detection accuracy.

[0029] The axial limiting device of the linear variable differential transformer 1 can be any device that can limit the axial movement of the coil assembly 12 on the pressure tube 11. The axial limiting device of the utility model can preferably improve the simplicity of assembly of the linear variable differential transformer 1 and can buffer environmental vibration.

[0030] According to a preferred embodiment of the utility model, the axial limiting device of the linear variable differential transformer 1 may include a fixture located on the outer end 121 of the coil assembly 12 and fixed on the pressure tube 11, and an elastic deformation device located on the inner end 122 of the coil assembly 12. The fixture and the elastic deformation device work together to limit the movement of the coil assembly 12 on the pressure tube 11 along the axial direction.

[0031] The linear variable differential transformer 1 of the utility model effectively restricts the coil assembly 12 to a predetermined fixed position on the pressure tube 11 through the coordinated action of the fixer and the elastic deformation device, so as to ensure the stability and accuracy of the linear variable differential transformer 1 during operation.

[0032] In addition, during assembly, the pressure tube 11 can be first inserted into the plug 22 from one side of the plug 22, and then the elastic deformation device and the coil assembly 12 can be sequentially sleeved onto the pressure tube 11 from the other side of the plug 22, and finally the fixture can be installed. The utility model simplifies the assembly process, saves assembly time, and improves assembly flexibility.

[0033] In addition, since the axial limit device of the coil assembly adopts an elastic deformation device, when the application environment of the linear variable differential transformer 1 is vibrating, the elastic deformation device can assist in buffering the vibration, thereby ensuring the accuracy and reliability of its displacement monitoring, thereby ensuring the accuracy and performance of the hydraulic valve used by the linear variable differential transformer 1, and effectively reducing the error of the system. The elastic deformation device can reduce the excessive movement or oscillation of the coil assembly caused by mechanical vibration or impact, thereby improving the stability and response speed of the LVDT sensor.

[0034] According to a preferred embodiment of the present invention, the elastic deformation device is a compression spring 15. According to other embodiments of the present invention, the elastic deformation device can be a corrugated metal washer, an open washer, a rubber ring, an asbestos washer, etc.

[0035] According to the utility model, the side of the inner end portion 122 of the coil assembly 12 that cooperates with the plug 22 may be a flat side, or may be provided with a groove 221 for accommodating the compression spring 15 .

[0036] According to the present invention, the outer end portion 121 of the blocking coil assembly 12 and the fixer fixed to the pressure tube 11 may be a clamping ring 14 or a locking nut, etc., but the present invention is not limited thereto.

[0037] The utility model Figure 1 to Figure 2 The outer end portion 121 of the coil assembly 12 of the linear variable differential transformer 1 is fixed to the pressure tube 11 by a clamping ring 14 .

[0038] According to the utility model Figure 1 to Figure 2 In the embodiment shown, the compression spring 15 of the linear variable differential transformer 1 is sleeved on the pressure tube 11 and its two ends respectively abut against the inner end 122 of the coil assembly 12 and the plug 22 of the hydraulic valve 2 to limit the position of the inner end 122 of the coil assembly 12 on the pressure tube 11. Such a structure is convenient for assembly and can buffer environmental vibration. The clamping ring 14 of the linear variable differential transformer 1 is clamped on the pressure tube 11 to limit the position of the outer end 121 of the coil assembly 12 on the pressure tube 11.

[0039] The linear variable differential transformer 1 of the present invention further includes an anti-rotation device to limit the rotation of the coil assembly 12 on the pressure tube 11. Any device capable of preventing rotation is not limited.

[0040] According to a preferred embodiment of the utility model, the anti-rotation device is a shape-matching structure between the inner end 122 of the coil assembly 12 and the plug 22 matched therewith, thereby realizing the anti-rotation effect through the design of a specific shape-matching structure. For example, the inner end 122 of the coil assembly 12 can be a non-circular cross-sectional structure. A groove 221 of a shape-matching non-circular cross-sectional structure is correspondingly provided on the plugs 22 that engage with each other. The shape-matching structure realized by the non-circular cross-section can prevent the rotation of the coil assembly 12. When the inner end 122 of the coil assembly 12 is accommodated in the groove 221 of the plug 22, it is shape-matched with the groove 221 of the plug 22 to prevent the coil assembly 12 from rotating in the circumferential direction.

[0041] The non-circular cross section is, for example, a polygon, such as a triangle, a quadrilateral, a pentagon, a hexagon, etc. Preferably, these polygons are regular polygons. According to a preferred embodiment, Figure 4 As shown, the inner end portion 122 of the coil assembly 12 is configured as a regular hexagonal structure. A regular hexagonal groove 221 matching in shape is formed on the plug 22 of the hydraulic valve 2, as shown in FIG. Figure 5 shown.

[0042] According to another preferred embodiment, the inner end 122 of the coil assembly 12 may be a toothed structure. A groove 221 with a matching shape is correspondingly provided on the corresponding plug 22. The matching shape of the teeth and the groove can prevent the rotation of the coil assembly 12. When the inner end 122 of the coil assembly 12 is accommodated in the groove 221 of the plug 22, the teeth on the inner end 122 match the shape of the groove in the groove 221 of the plug 22, which can limit the circumferential rotation of the coil assembly 12.

[0043] The shape of the teeth of the toothed structure is not limited, and may be teeth with a triangular cross section, teeth with a wavy cross section, teeth with a rectangular cross section, etc.

[0044] The extending direction of the teeth of the toothed structure is not limited, and the teeth of the toothed structure of the inner end 122 of the coil assembly 12 can be arranged radially or axially. For example, the inner end 122 of the coil assembly 12 can be arranged in a cross structure or a circumferentially arranged comb structure.

[0045] The number of teeth of the toothed structure is not limited, and the uniformity of distribution is not limited. The matching structure on the plug 22 only needs to form a shape match with the structure of the inner end portion 122 of the coil assembly 12.

[0046] In addition, non-circular cross-sectional structures and toothed structures can be combined. Figure 6 The inner end portion 122 of the coil assembly 12 according to an embodiment of the present invention is shown, which is configured to have a hexagonal cross section and a structure with two radial teeth 1221. A groove 221 with radial tooth grooves is formed on the outer side of the plug 22, which is the same shape as the inner end portion 122 with radial teeth 1221 and slightly larger in size. The restriction of rotation is provided by the hexagonal cross-sectional matching structure and the matching of the radial teeth 1221 with the radial tooth grooves. In the case of a larger diameter of the coil assembly, this radial tooth structure is more preferred, and the teeth are combined with a polygonal structure to further assist in preventing the coil assembly 12 from rotating relative to the pressure tube 11.

[0047] The arrangement of the matching structure between the inner end portion 122 of the coil assembly 12 and the plug 22 of the hydraulic valve 2 mentioned above can be reversed as long as conditions permit. For example, the axial teeth can be formed on the coil assembly 12, and the channel is correspondingly formed on the plug 22; but the axial teeth can also be formed on the plug 22, and the channel is correspondingly formed on the coil assembly 12.

[0048] According to another embodiment of the utility model, the anti-rotation device is not limited to being arranged on the inner end portion 122 of the coil assembly 12. It is also conceivable to arrange the anti-rotation device on the circumferential surface of the pressure tube 11 and the coil assembly 12. For example, an axially extending groove can be arranged on the pressure tube 11, and an axially extending protrusion can be arranged on the inner surface of the coil assembly 12. The protrusion on the coil assembly 12 can also limit the rotation of the coil assembly 12 by sliding into a suitable position along the groove on the pressure tube 11, and vice versa.

[0049] According to another aspect of the present invention, a hydraulic valve 2 is further provided, and the linear displacement of the valve core 21 of the hydraulic valve 2 is measured and monitored by the aforementioned linear variable differential transformer 1.

[0050] Figure 3 FIG. 2 shows a side view of a hydraulic valve 2 according to an embodiment of the present invention. Figure 3 As shown, the hydraulic valve 2 of the present invention comprises a linear variable differential transformer 1 , and the linear variable differential transformer 1 is mounted on a plug 22 of the hydraulic valve 2 .

[0051] Combine the following Figure 2 and Figure 3 The hydraulic valve 2 of the present invention is specifically described. For the purpose of brevity, the specific structure of the linear variable differential transformer 1 is not described here. The specific structure of the linear variable differential transformer 1 can be found in the previous description.

[0052] The hydraulic valve 2 of the utility model comprises a valve body, a plug 22 with a through hole 222, and the linear variable differential transformer 1 as described above. The plug 22 is installed on one side of the valve body, and the linear variable differential transformer 1 is installed on the plug 22. A structure for matching with the inner end 122 of the coil assembly 12 of the linear variable differential transformer 1 is provided on the outer end of the plug 22. According to a preferred embodiment of the utility model, the outer end of the plug 22 and the inner end 122 of the coil assembly 12 are engaged with each other through a shape matching structure to prevent the coil assembly 12 from rotating. Preferably, the plug 22 can be a screw plug.

[0053] In order to adapt to the positioning and installation of the linear variable differential transformer to the hydraulic valve body, the outer end of the plug of the utility model can be provided with a groove for accommodating the inner end of the coil assembly, and the cross-sectional shape of the groove corresponds to the cross-sectional shape of the inner end of the coil assembly. Such a groove structure is a non-circular cross-sectional structure for preventing rotation, such as a polygonal cross-sectional groove, a wavy circular cross-sectional groove, a radially arranged tooth groove structure, etc. Of course, the outer end of the plug can also be provided with a protrusion, and the groove can be correspondingly provided on the inner end of the coil assembly for this purpose.

[0054] According to one embodiment of the utility model, Figure 5 As shown, the groove 221 of the plug 22 is configured in the shape of a regular hexagonal cross section, which can accommodate Figure 4 The inner end 122 of the coil assembly 12 shown has a regular hexagonal cross section and forms a shape-fitting structure to prevent the coil assembly 12 from rotating. The size of the groove 221 of the plug 22 is slightly larger than the inner end 122 of the coil assembly 12 to accommodate the inner end 122 of the coil assembly 12.

[0055] This form-fitting configuration between the outer end of the plug and the inner end of the coil assembly locks the coil assembly and prevents it from circumferential rotation, thereby ensuring the performance and reliability of the hydraulic valve. This assembly and positioning mechanism is also critical for accurate signal conversion of LVDT sensors in hydraulic valves.

[0056] In addition, the utility model also takes into account the adaptation problem of components of different sizes, ensuring that even when the size of the groove on the plug is large, the coil assembly can be stably positioned and prevented from rotating in the circumferential direction.

[0057] The utility model not only improves the flexibility of assembly, but also can adapt to different assembly requirements, ensuring the accuracy and reliability of the linear variable differential transformer in the hydraulic valve. Through the technical solution of the utility model, the error can be effectively reduced and the performance of the hydraulic valve can be improved.

[0058] The above specific embodiments are only used to illustrate the present invention, but not to limit the present invention. Those skilled in the art can make various modifications and variations without departing from the inventive concept of the present invention, so all equivalent technical solutions fall within the protection scope of the present invention, and the protection scope of the present invention is defined by the attached claims.

Claims

1. A linear variable differential transformer (1) for a hydraulic valve (2), characterized in that: The linear variable differential transformer (1) comprises a pressure tube (11), a coil assembly (12), a ferromagnetic core (13), an axial limit device and an anti-rotation device, wherein the ferromagnetic core (13) of the linear variable differential transformer (1) is fixedly connected to the valve core (21) of the hydraulic valve (2) to detect the displacement of the valve core (21), wherein: The pressure tube (11) is fixedly installed in a through hole (222) on a plug (22) of the hydraulic valve (2), so that an inner channel of the pressure tube (11) is aligned with and communicated with a valve core channel of the hydraulic valve (2); The ferromagnetic core (13) is located in the inner channel of the pressure tube (11) and is linked to the valve core (21) of the hydraulic valve (2); and The coil assembly (12) is guided by the pressure tube (11) and is sleeved outside the pressure tube (11); the coil assembly (12) is limited in axial movement by the axial limiting device and is prevented from rotating in the circumferential direction by the anti-rotation device; The axial limiting device comprises: a fixture abutting against the outer end (121) of the coil assembly (12) and fixedly engaged with the pressure tube (11); and an elastic deformation device abutting between the inner end (122) of the coil assembly (12) and the plug (22), wherein the elastic deformation device cooperates with the fixture to limit the axial position of the coil assembly (12) on the pressure tube (11).

2. The linear variable differential transformer (1) according to claim 1, characterized in that: The elastic deformation device is a compression spring (15) or a washer.

3. The linear variable differential transformer (1) according to claim 1, characterized in that: The fixer is a clamping ring (14) or a locking nut.

4. The linear variable differential transformer (1) according to any one of claims 1 to 3, characterized in that: The anti-rotation device is a shape-matching structure between the inner end (122) of the coil assembly (12) and the plug (22).

5. The linear variable differential transformer (1) according to claim 4, characterized in that: The shape-fitting structure includes an inner end (122) of a non-circular cross section of the coil assembly (12), wherein the inner end (122) of the non-circular cross section is accommodated in a shape-fitting groove (221) formed on the plug (22) to prevent the coil assembly (12) from rotating.

6. The linear variable differential transformer (1) according to claim 5, characterized in that: The non-circular cross section is a polygonal cross section, a toothed cross section and a combination thereof.

7. A hydraulic valve (2), characterized in that: The hydraulic valve (2) comprises a valve body, a valve core (21), a plug (22) having a through hole (222), and a linear variable differential transformer (1) according to any one of claims 1 to 6, wherein the linear variable differential transformer (1) comprises a pressure tube (11), a coil assembly (12), a ferromagnetic core (13), an axial limit device and an anti-rotation device, and the valve core (21) of the hydraulic valve (2) is fixedly connected to the ferromagnetic core (13) of the linear variable differential transformer (1) so as to detect the displacement of the valve core (21) through the linear variable differential transformer (1), wherein: The pressure tube (11) is fixedly mounted on the through hole (222) of the plug (22), so that the valve core channel of the hydraulic valve (2) is aligned with and communicated with the inner channel of the pressure tube (11); The valve core (21) of the hydraulic valve (2) is linked to the ferromagnetic core (13); and The pressure tube (11) guides the coil assembly (12) and the coil assembly (12) is sleeved outside the pressure tube (11), and the coil assembly (12) is limited in axial movement by an axial limiting device and prevented from rotating in the circumferential direction by an anti-rotation device. Wherein, the anti-rotation device is a shape-matching structure between the inner end (122) of the coil assembly (12) and the plug (22).

8. The hydraulic valve (2) according to claim 7, characterized in that The shape-fitting structure comprises an inner end (122) of the coil component (12) with a non-circular cross-section and a groove (221) with a non-circular cross-section formed on the plug (22), wherein the non-circular cross-section of the inner end (122) is complementary to the non-circular cross-section of the groove (221) to prevent the coil component (12) from rotating.

9. The hydraulic valve (2) according to claim 8, characterized in that The non-circular cross section is a polygonal cross section, a toothed cross section and a combination thereof.

10. The hydraulic valve (2) according to any one of claims 7 to 9, characterized in that The plug (22) is a screw plug.

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