Filter

Abstract

The invention belongs to the technical field of radio frequency communication, and provides a filter which comprises a cavity with an opening in one end, a cover plate installed at the opening end of the cavity, a resonant column installed in the cavity and a tuning mechanism installed on the cover plate and opposite to the resonant column, and the tuning mechanism comprises an adjusting nut, a tuning screw and an elastic piece. The adjusting nut and the cover plate are connected in a pressing rivet mode so that the adjusting nut can rotate relative to the cover plate and be axially limited, the tuning screw is connected into the adjusting nut in a threaded mode, the first end of the tuning screw extends out of the first end of the adjusting nut and is located outside the cavity, and the second end of the tuning screw extends out of the second end of the adjusting nut and is located in the cavity. The elastic piece is arranged in the cavity, a certain reserved deformation space is formed between the elastic piece and the inner side of the cover plate, the center of the elastic piece is fixedly connected with the tuning screw, and the periphery of the elastic piece is fixedly connected with the inner side of the cover plate or the opening of the cavity. According to the invention, metal chips can be prevented from entering the cavity, so that the product quality is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of radio frequency communications, and in particular relates to a filter. Background Art

[0002] Currently, RF device tuning devices generally use a metal screw that extends through a screw hole in the cover plate into the cavity for tuning, and is locked in place with a nut. However, the repeated rotation of the screw for tuning can easily cause burrs and dust to form on the metal screw, which can fall into the cavity and interfere with the filtered signal. For example, during power testing, this can easily cause technical problems such as power sparks, intermodulation failures, and unstable indicators, seriously affecting product quality and debugging efficiency. With the development of RF communication technology, frequency bands will become higher and indicators will become more stringent. However, the traditional debugging method of using a tuning screw with a screw hole in the cover plate is increasingly unable to meet the product's requirements for frequency and intermodulation indicators. Summary of the Invention

[0003] The present invention aims to prevent or reduce metal debris from entering the cavity of a filter.

[0004] To achieve the above object, the technical solution adopted by the present invention is: A filter comprises a cavity with an opening at one end, a cover plate installed at the open end of the cavity, a resonant column installed in the cavity, and a tuning mechanism installed on the cover plate and opposite to the resonant column, the tuning mechanism comprising an adjusting nut, a tuning screw and an elastic member, the adjusting nut and the cover plate are riveted so that the adjusting nut can rotate relative to the cover plate and be axially limited, the tuning screw is threadedly connected to the adjusting nut, the first end of the tuning screw extends from the first end of the adjusting nut and is located outside the cavity, the second end of the tuning screw extends from the second end of the adjusting nut and is located in the cavity, the elastic member is arranged in the cavity and a certain reserved deformation space is provided between the elastic member and the inner side of the cover plate, the center of the elastic member is fixedly connected to the tuning screw, and the periphery of the elastic member is fixedly connected to the inner side of the cover plate or the cavity opening.

[0005] Preferably, the adjusting nut includes a nut body, a positioning portion extending outward from the nut body, and a riveted portion located at the end of the nut body. After the riveted portion is riveted to the cover plate, it and the positioning portion are located on both sides of the cover plate, respectively, so that the adjusting nut can rotate relative to the cover plate, and the axial movement of the adjusting nut relative to the cover plate is restricted.

[0006] Preferably, a stop step is provided at the first end of the tuning screw, and a gap is provided between the stop step and the first end surface of the adjusting nut for limiting the downward displacement of the tuning screw.

[0007] Preferably, the elastic member includes an annular spring, which includes a reed body and a flange structure extending axially at the center of the reed body, the flange structure is fixedly connected to the outer periphery of the second end of the tuning screw, and there is a gap between the flange structure and the second end face of the adjusting nut for limiting the upward displacement of the tuning screw.

[0008] Preferably, the annular spring further comprises a step structure provided on the outer periphery of the spring body, the step structure protrudes toward the inner side of the cover plate, and the step structure is fixedly connected to the inner side of the cover plate.

[0009] Preferably, a positioning groove corresponding to the step structure is provided on the inner side of the cover plate, and the step structure is fixedly connected to the positioning groove to achieve a fixed connection between the outer periphery of the annular spring and the inner side of the cover plate.

[0010] Preferably, the flange structure and the tuning screw, and the step structure and the positioning groove are fixedly connected by welding, so that the elastic member, the cover plate and the tuning screw are fixed as one.

[0011] Preferably, a groove is provided on the inner side of the cover plate at a position corresponding to the reed body.

[0012] Preferably, two resonant columns are provided in the cavity of the filter, and two corresponding filter tuning mechanisms are provided. The filter also includes a coupling adjustment mechanism arranged between the two filter tuning mechanisms, the coupling adjustment mechanism includes a rivet nut, a medium, a coupling screw and a nut, the cover plate is provided with a stepped hole with a larger upper portion and a smaller lower portion at the corresponding position, the medium includes a cylindrical portion extending axially and a flange portion extending radially, the cylindrical portion of the medium extends from the small hole of the stepped hole, and its flange portion conflicts with the step of the stepped hole, the rivet nut is fixedly installed in the large hole of the stepped hole and fixedly connects the rivet nut, the medium and the cover plate as one, the coupling screw is threadedly connected to the rivet nut, the first end of the coupling screw is located outside the cavity and is locked by a nut, the second end of the coupling screw passes through the medium and extends into the cavity between the two coupling adjustment mechanisms, the coupling screw and the medium are in close contact and can rotate relative to each other.

[0013] Preferably, the medium is made of non-metallic material.

[0014] Compared with the prior art, the present invention uses the threaded connection between the adjusting nut and the tuning screw and the fixed connection between the elastic part and the tuning screw. When adjusting the frequency, it is only necessary to slightly rotate the adjusting nut to drive the tuning screw to move up and down, thereby causing the elastic part to deform slightly upward or downward to achieve frequency changes. The adjustment is simple, and since the elastic part is fixedly connected to the tuning screw and the cover plate (or the cavity opening), metal chips generated during the rotation of the tuning screw and the adjusting nut fall onto the elastic part, completely preventing the metal chips from entering the cavity, effectively solving technical problems such as power sparking, intermodulation failure, and unstable indicators caused by metal chips entering the cavity, and greatly improving the quality of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which: Figure 1 A three-dimensional schematic diagram of a filter tuning mechanism provided by an embodiment of the present invention; Figure 2 An exploded schematic diagram of a filter tuning mechanism provided by an embodiment of the present invention; Figure 3 A cross-sectional schematic diagram of a filter tuning mechanism provided in an embodiment of the present invention.

[0016] In the figure: 10-cavity; 11-cover; 11.1-positioning groove; 11.2-groove; 12-resonant column; 20-annular reed; 20.1-flanged structure; 20.2-step structure; 20.3-reed body; 21-adjusting nut; 21.1-riveted part; 21.2-positioning part; 21.3-nut body; 22-tuning screw; 22.1-stop step; 30-medium; 31-riveted nut; 32-nut; 33-coupling screw. DETAILED DESCRIPTION

[0017] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0018] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like to indicate directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the devices or elements referred to must have a specific direction, be constructed and operate in a specific direction, and therefore should not be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0019] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be internal communication between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. In addition, in the description of the present invention, unless otherwise specified, "multiple" and "several" mean two or more.

[0020] like Figure 1-Figure 3 As shown, the present invention provides a filter, comprising a cavity 10 with an opening at one end, a cover plate 11 installed at the open end of the cavity 10, a resonant column 12 installed in the cavity, and a tuning mechanism installed on the cover plate 11 and opposite to the resonant column 12, the tuning mechanism comprising an adjusting nut 21, a tuning screw 22 and an elastic member (the elastic member is an annular spring 20 in this embodiment), the adjusting nut and the cover plate are riveted so that the adjusting nut can rotate relative to the cover plate and be axially limited, the tuning screw 22 is threadedly connected to the adjusting nut 21, the first end of the tuning screw 22 extends from the first end of the adjusting nut 21 and is located outside the cavity 10, the second end of the tuning screw 22 extends from the second end of the adjusting nut 21 and is located in the cavity 10, the elastic member is arranged in the cavity and a certain reserved deformation space is provided between the elastic member and the inner side of the cover plate, the center of the elastic member is fixedly connected to the tuning screw, and the outer periphery of the elastic member is fixedly connected to the inner side of the cover plate or the cavity opening. Preferably, the outer periphery of the elastic member is fixed to the inner side of the cover plate. The inner side of the cover plate is the side closest to the resonant column, and the outer side of the cover plate is the side opposite the inner side. The first end of the adjusting nut and the first end of the tuning screw are both the ends away from the resonant column, while the second end of the adjusting nut and the second end of the tuning screw are both the ends closer to the resonant column. In this embodiment, a hexagonal recess is provided at the top of the tuning screw. When turning the adjusting nut, a hexagonal screwdriver can be inserted into the recess to prevent the tuning screw from rotating.

[0021] Further, such as Figure 2、 Figure 3 As shown, the adjusting nut 21 includes a nut body 21.3, a positioning portion 21.2 extending outward from the nut body, and a rivet portion 21.1 located at the end of the nut body. After the rivet portion 21.1 is riveted to the cover plate 11, it and the positioning portion 21.2 are located on either side of the cover plate 11, allowing the adjusting nut 21 to rotate relative to the cover plate 11. The axial movement of the adjusting nut 21 relative to the cover plate 11 is restricted, preventing it from falling out of the cover plate. After the adjusting nut is connected to the cover plate, it has only one degree of rotational freedom. Simply rotating the adjusting nut 21 can move the tuning screw 22, thereby achieving frequency change. Specifically, the rivet portion is truncated cone-shaped. The gap between the rivet portion and the positioning portion forms a guide groove. Pressure is applied to force the rivet portion into the pre-set hole in the cover plate. Because the diameter of the pre-set hole is smaller than the outer diameter of the rivet portion, plastic deformation occurs around the pre-set hole. The deformed material is squeezed into the guide groove and stops at the positioning portion, allowing the adjusting nut to rotate without falling out.

[0022] In one embodiment, Figure 2 、 Figure 3 As shown, the first end of the tuning screw 22 is provided with a stop step 22.1. A gap exists between the stop step 22.1 and the first end surface of the adjusting nut 21 to limit the downward displacement of the tuning screw. Preferably, this gap is 0.5-1 mm. When the adjusting nut is rotated to move the tuning screw downward, it can only move until the stop step contacts the first end surface of the adjusting nut, thereby controlling the downward adjustment of the elastic member.

[0023] In one embodiment, Figure 2 、 Figure 3 As shown, the elastic member includes an annular spring 20, which includes a spring body 20.3 and an axially extending flange structure 20.1 provided at the center of the spring body 20.3. The flange structure 20.1 is fixedly connected to the outer periphery of the second end of the tuning screw 22. A gap is defined between the flange structure 20.1 and the second end face of the adjusting nut 21 to limit the upward displacement of the tuning screw. Preferably, the gap is 0.5-1 mm, and the thickness of the annular spring is 0.2-0.5 mm. The flange structure can increase the contact area between the annular spring and the tuning screw, facilitate welding to the tuning screw, and provide a tighter connection between the two. Furthermore, a gap is defined between the flange structure and the second end face of the adjusting nut. When the adjusting nut is rotated to move the tuning screw upward, the tuning screw can only move to the point where the top of the flange structure contacts the second end face of the adjusting nut, thereby controlling the upward adjustment of the tuning screw.

[0024] Further, such as Figure 2 、 Figure 3As shown, the annular spring 20 also includes a stepped structure 20.2 provided on the outer periphery of the spring body 20.3. The stepped structure 20.1 protrudes toward the inner side of the cover plate and is fixedly connected to the inner side of the cover plate 11. The provision of the stepped structure provides a better connection with the cover plate. The annular spring is a thin-walled sheet metal part that can be formed by a stamping process.

[0025] Further, such as Figure 2 、 Figure 3 As shown, a positioning groove 11.1 corresponding to the step structure is provided on the inner side of the cover plate 11. The step structure is fixedly connected to the positioning groove to achieve a fixed connection between the outer periphery of the annular spring and the inner side of the cover plate. The cooperative positioning groove can facilitate the positioning and placement of the annular spring.

[0026] Further, such as Figure 2 、 Figure 3 As shown, the flange structure and the tuning screw, as well as the step structure and the positioning groove, are all welded together, securing the elastic member, cover plate, and tuning screw together. In this embodiment, the annular spring, tuning screw, and cover plate are soldered together. The tuning screw is passed through the adjusting nut and pre-cut to length using a tool. The inner side of the cover plate is then coated with solder paste, and the annular spring is placed inside. The annular spring and the cover plate are then welded together.

[0027] Further, such as Figure 2 、 Figure 3 As shown, a groove 11.2 is provided on the inner side of the cover plate 11 at a position corresponding to the reed body, so as to increase the space between the reed body and the cover plate.

[0028] In one embodiment, Figure 2 、 Figure 3 As shown, two resonant columns 12 are provided in the cavity of the filter, and two corresponding tuning mechanisms are provided. The filter also includes a coupling adjustment mechanism arranged between the two filter tuning mechanisms, the coupling adjustment mechanism includes a rivet nut 31, a medium 30, a coupling screw 33 and a nut 32, and the cover plate is provided with a stepped hole with a larger upper portion and a smaller lower portion at the corresponding position. The medium includes a cylindrical portion extending axially and a flange portion extending radially. The cylindrical portion of the medium extends from the small hole of the stepped hole, and its flange portion conflicts with the step of the stepped hole. The rivet nut is fixedly installed in the large hole of the stepped hole and the rivet nut, the medium and the cover plate are fixedly connected as one. The coupling screw is threadedly connected to the rivet nut. The first end of the coupling screw is located outside the cavity and is locked by the nut. The second end of the coupling screw passes through the medium and extends into the cavity between the two coupling adjustment mechanisms. The coupling screw and the medium are in close contact and can rotate relative to each other. During the up and down tuning process of the coupling screw in the rivet nut, due to the close contact between the coupling screw and the medium, debris generated when the coupling screw rotates relative to the rivet nut can be prevented or reduced from falling into the cavity.

[0029] In this embodiment, the nut and the coupling screw are threadedly connected, and there is a hexagonal recess on the top of the coupling screw. The coupling screw can be rotated by inserting a hexagonal screwdriver into the recess. When the coupling screw is rotated to a preset position, the locking nut needs to be tightened. The hexagonal screwdriver is inserted into the recess to keep the coupling screw from rotating and screw the nut to abut against the rivet nut, thereby locking the coupling screw.

[0030] Further, such as Figure 2 、 Figure 3 As shown, the medium is made of non-metallic material. Preferably, the medium can be a thin plastic piece to achieve close contact between the medium and the coupling screw and enable relative rotation between the two.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A filter comprising a cavity with an open end, a cover plate mounted on the open end of the cavity, a resonant column mounted in the cavity, and a tuning mechanism mounted on the cover plate and opposite to the resonant column, characterized in that: The tuning mechanism includes an adjusting nut, a tuning screw and an elastic member. The adjusting nut and the cover plate are riveted so that the adjusting nut can rotate relative to the cover plate and be axially limited. The tuning screw is threadedly connected to the adjusting nut. The first end of the tuning screw extends from the first end of the adjusting nut and is located outside the cavity. The second end of the tuning screw extends from the second end of the adjusting nut and is located in the cavity. The elastic member is arranged in the cavity and a certain reserved deformation space is provided between the elastic member and the inner side of the cover plate. The center of the elastic member is fixedly connected to the tuning screw, and the periphery of the elastic member is fixedly connected to the inner side of the cover plate or the opening of the cavity.

2. The filter according to claim 1, wherein The adjusting nut includes a nut body, a positioning portion extending outward from the nut body, and a riveted portion located at the end of the nut body. After the riveted portion is riveted to the cover plate, it and the positioning portion are located on both sides of the cover plate respectively, so that the adjusting nut can rotate relative to the cover plate, and the axial movement of the adjusting nut relative to the cover plate is restricted.

3. The filter according to claim 1, wherein A stop step is provided at the first end of the tuning screw, and a gap is provided between the stop step and the first end surface of the adjusting nut for limiting the downward displacement of the tuning screw.

4. The filter according to claim 1, wherein The elastic member includes an annular spring, which includes a spring body and a flange structure extending axially at the center of the spring body. The flange structure is fixedly connected to the outer periphery of the second end of the tuning screw. There is a gap between the flange structure and the second end face of the adjusting nut for limiting the upward displacement of the tuning screw.

5. The filter according to claim 4, characterized in that The annular spring further includes a step structure provided on the outer periphery of the spring body, the step structure protruding toward the inner side of the cover plate, and the step structure is fixedly connected to the inner side of the cover plate.

6. The filter according to claim 5, characterized in that A positioning groove corresponding to the step structure is provided on the inner side of the cover plate, and the step structure is fixedly connected to the positioning groove to achieve a fixed connection between the outer periphery of the annular spring and the inner side of the cover plate.

7. The filter according to claim 6, characterized in that The flange structure and the tuning screw, and the step structure and the positioning groove are all fixedly connected by welding, so that the elastic member, the cover plate and the tuning screw are fixed into one body.

8. The filter according to claim 4, characterized in that A groove is provided on the inner side of the cover plate at a position corresponding to the reed body.

9. The filter according to claim 1, wherein Two resonant columns are provided in the cavity of the filter, and two corresponding filter tuning mechanisms are provided. The filter also includes a coupling adjustment mechanism arranged between the two filter tuning mechanisms, the coupling adjustment mechanism includes a rivet nut, a medium, a coupling screw and a nut, and the cover plate is provided with a stepped hole with a larger upper portion and a smaller lower portion at the corresponding position, the medium includes a cylindrical portion extending axially and a flange portion extending radially, the cylindrical portion of the medium extends from the small hole of the stepped hole, and its flange portion conflicts with the step of the stepped hole, the rivet nut is fixedly installed in the large hole of the stepped hole and the rivet nut, the medium and the cover plate are fixedly connected as one, the coupling screw is threadedly connected to the rivet nut, the first end of the coupling screw is located outside the cavity and is locked by a nut, the second end of the coupling screw passes through the medium and extends into the cavity between the two coupling adjustment mechanisms, and the coupling screw and the medium are in close contact and can rotate relative to each other.

10. The filter according to claim 9, characterized in that The medium is made of non-metallic material.

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