Junction box with double-wire contact sealing structure

Abstract

The utility model discloses a junction box with a double-line contact sealing structure. The junction box comprises a box cover, a box body, a limiting structure, an annular convex rib structure and a sealing strip. The limiting structure is fixed at the opening of the box body. The annular convex rib structure is fixed to the inner side face of the box cover. The limiting structure is provided with a bevel edge part which surrounds the limiting structure by a circle. The sealing strip is arranged on the bevel edge portion of the limiting structure. And the outer side surface of the annular convex rib structure is an inclined sealing surface. And the sealing strip surrounding a circle is arranged between the bevel edge part of the limiting structure and the inclined sealing surface of the annular convex rib structure. According to the junction box provided by the utility model, when the box cover is closed, the edge of the sealing strip abuts against the bottom surface of the box cover preferentially to form first line contact, and after the box cover continues to be closed, the tip of the annular convex rib structure on the box cover abuts against the side surface of the sealing strip to form second line contact; according to the double-line sealing structure, the protection performance is improved, the phenomenon that the sealing strip is excessively deformed to generate a negative pressure area due to direct surface contact extrusion of the sealing strip is avoided, and meanwhile the service life of the sealing strip can be prolonged.

Description

Technical Field

[0001] The utility model belongs to the technical field of rail transit sealed wiring equipment, and in particular relates to a junction box with a double-wire contact sealing structure. Background Art

[0002] Junction boxes are essential equipment in industrial and rail transit applications. They primarily connect electrical components and transmit signals, and their sealing performance directly impacts the stability and service life of the equipment. Traditional junction boxes either have poor sealing, resulting in low waterproof ratings and susceptibility to environmental influences; or they have excessive sealing, leading to negative pressure within the box after experiencing hot and cold weather cycles, causing the cover to become firmly attached to the box, making it difficult to remove. These issues severely impact the efficiency and safety of the junction box.

[0003] Solutions of existing technologies: Existing solutions mainly improve the waterproof performance of the junction box by improving its sealing structure. For example, some junction boxes use a double-layer sealing structure to improve waterproof performance. First, the existing junction box sealing structure design still cannot completely avoid long-term surface contact between the box body and the cover and the sealing strip, which may lead to the formation of a negative pressure area and increase the risk of the entire sealing structure being affected by negative pressure. Secondly, during the use of the existing junction box sealing structure, the sealing strip may accelerate aging due to excessive compression, thereby affecting the sealing effect and service life. Finally, the existing junction box sealing structure also has the problem of cumbersome assembly when used in the application of under-vehicle hoisting. Summary of the Invention

[0004] The purpose of the utility model is to provide a junction box with a double-wire contact sealing structure.

[0005] The present invention provides a junction box with a dual-wire contact sealing structure, comprising a box cover, a box body, a retaining structure, an annular rib structure, and a sealing strip. The retaining structure is fixed to the box body opening. The annular rib structure is fixed to the inner side of the box cover. The retaining structure is provided with a circumferential beveled edge. The sealing strip is disposed on the beveled edge of the retaining structure. The outer side of the annular rib structure forms an inclined sealing surface. The circumferential sealing strip is disposed between the beveled edge of the retaining structure and the inclined sealing surface of the annular rib structure.

[0006] Preferably, the top of the sealing strip abuts against the bottom surface of the box cover to form a first sealing line, and the bottom of the annular rib structure abuts against the side of the sealing strip away from the oblique edge to form a second sealing line.

[0007] Preferably, the inclination angle θ of the bevel portion is 35° to 65°. The inclination angle φ and the inclination angle θ of the inclined sealing surface satisfy the following relationship: 3°≤φ-θ≤6°.

[0008] Preferably, the retaining structure is annular and includes a horizontal portion, a beveled portion, and a beveled skirt, sequentially connected from the inner sidewall of the box toward the center of the box. The beveled portion bends inward relative to the horizontal portion. The outer periphery of the horizontal portion of the retaining structure is connected to the inner sidewall of the box. The beveled portion and the beveled skirt form a V-shaped structure that constrains the sealing strip.

[0009] Preferably, the plane of the box top opening outline is used as the box opening reference plane. The horizontal portion is parallel to the box opening reference plane and is 3mm to 8mm lower than the box opening reference plane. The width of the chute skirt is 6mm to 10mm.

[0010] Preferably, the width of the bevel portion is 14 mm to 35 mm.

[0011] Preferably, the width of the sealing strip is equal to the width of the bevel portion; the thickness of the sealing strip is less than the width of the bevel skirt.

[0012] Preferably, a downwardly folded flange structure is provided at the outer periphery of the horizontal portion; the inner side wall of the box body of the flange structure is fixed.

[0013] Preferably, the height of the annular rib structure is 7 mm to 25 mm. The annular rib structure and the box cover are an integral structure formed by bending sheet metal.

[0014] Preferably, the longitudinal section of the sealing strip is a rounded rectangle;

[0015] The beneficial effects of the utility model are:

[0016] 1. When the junction box provided by the present invention is closed, the edge of the sealing strip and the bottom surface of the box cover preferentially form a first line of contact. After the box cover is closed further, the tip of the annular rib structure on the box cover and the side surface of the sealing strip form a second line of contact. This double-line contact sealing structure not only increases the protective performance but also avoids direct surface contact and squeezing of the sealing strip, which causes excessive deformation of the sealing strip and creates a negative pressure zone. It also increases the service life of the sealing strip. In addition, during the installation process, the sealing structure will preferentially form the first line of contact. After the bolts are fully tightened, the second line of contact of the sealing mechanism between the box body and the box cover is formed. Instead of using a complex double-layer sealing structure to achieve the purpose of improving the sealing effect, the operation is simpler and more reasonable.

[0017] 2. The double-line contact design of the sealing structure in the present invention can also avoid the risk of accelerated aging of the sealing strip due to excessive compression. At the same time, the second line contact of the inclined rib side against the plane of the sealing strip will also adaptively displace as the sealing strip gradually ages, thereby adaptively adjusting the position of the second line contact, thereby extending the service life of the sealing structure.

[0018] 3. The bell-shaped design of the box's sealing structure in this utility model is particularly suitable for junction boxes mounted under vehicles. Such junction boxes are hoisted upside down from the vehicle's bottom. The bell-shaped design ensures that after a certain negative pressure is formed within the box during climate circulation, the internal negative pressure can be gradually released, reducing the possibility of negative pressure inside the box. Compared with existing technologies, this utility model can adapt to different working environments, improving the adaptability and practicality of the equipment.

[0019] 4. The annular rib structure on the bottom surface of the box cover not only acts as a seal against the sealing strip to form a seal, but also acts as a reinforcement to enhance the box cover's bending resistance. Furthermore, the retaining structure in this utility model is recessed 3mm to 8mm relative to the box opening, allowing the box cover to enter the box, improving the integrity and stability of the junction box. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the explosion structure of the utility model;

[0021] Figure 2 It is a schematic diagram of the cross-sectional structure of the utility model;

[0022] Figure 3 This is a schematic diagram of the assembly of the limiting structure, sealing strip and annular rib structure in the utility model (ie Figure 2 A partial enlarged view of part A in the middle);

[0023] Figure 4 This is a schematic diagram of the partial structure of the limiting structure of the utility model;

[0024] Figure 5 It is a cross-sectional schematic diagram of the box cover and the annular rib structure of the present invention;

[0025] Figure 6 This is a partial structural diagram of the annular rib structure in the utility model (i.e. Figure 5 (a partial enlarged view of part B in FIG);

[0026] Figure numerals: 1. Box cover; 2. Box body; 3. Limiting structure; 3-1. Horizontal part; 3-2. Beveled edge; 3-3. Beveled groove skirt; 3-4. Flanged structure; 3-5. Blind hole nut; 4. Annular rib structure; 4-1. Inclined sealing surface; 5. Sealing strip. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to the accompanying drawings.

[0028] like Figure 1 and 2As shown, a junction box with a dual-line contact sealing structure includes a box cover 1, a box body 2, a retaining structure 3, an annular rib structure 4, and a sealing strip 5. The retaining structure 3 is fixed to the top opening of the box body 2. The annular rib structure 4 is fixed to the bottom surface of the box cover 1. The sealing strip 5 is disposed between the retaining structure 3 and the annular rib structure 4 to achieve a seal between the box cover 1 and the box body 2.

[0029] In some embodiments, the housing 2 is formed by bending sheet metal, primarily made of lightweight, high-strength materials such as stainless steel or aluminum alloy, to achieve a low-cost, lightweight, corrosion-resistant, and reliable structure. The shape of the housing 2 is designed based on actual conditions. In this embodiment, the housing 2 has an overall dimension of 620 mm × 560 mm × 300 mm.

[0030] In some embodiments, the annular rib structure 4 is integrally formed with the lid 1 through a sheet metal bending process. Specifically, the annular rib structure 4 is formed by machining a rib on the edge of the lid 1 and then folding it downward 180°. The sheet metal is primarily constructed from lightweight, high-strength materials such as stainless steel or aluminum alloy, achieving a low-cost, lightweight, corrosion-resistant, and reliable structure. The shape of the lid 1 is designed based on actual conditions and the structure of the box body 2. In this embodiment, the lid 1 has dimensions of 550 mm × 540 mm × 14 mm.

[0031] like Figure 3 and 4 As shown, the limiting structure 3 is an annular, trumpet-shaped, angular groove structure. The limiting structure 3 is located inside the housing 2, and its upper surface is sequentially connected from the outside to the inside by a horizontal portion 3-1, a bevel portion 3-2, and a angular groove skirt 3-3. The outer periphery of the horizontal portion 3-1 of the limiting structure 3 is sealed and fixed to the top of the inner wall of the housing 2. A downwardly folded flange structure 3-4 is provided on the outer periphery of the horizontal portion 3-1 to increase the contact area between the horizontal portion 3-1 and the inner wall of the housing 2. In some embodiments, the flange structure 3-4 is welded and fixed to the inner wall of the housing 2.

[0032] The plane of the top opening of the box body 2 is used as the box opening reference plane. The horizontal portion 3-1 is parallel to the box opening reference plane and is 3mm to 8mm (preferably 4mm) lower than the box opening reference plane. This allows the outer contour of the box cover 1 to be completely embedded in the box body 2 when the junction box is closed, preventing the box cover 1 from protruding beyond the box opening.

[0033] The outer edge of the beveled edge 3-2 is connected to the inner edge of the horizontal portion 3-1. From the outside inward, the beveled edge 3-2 is inclined toward the interior of the box body 2 (i.e., away from the top opening of the box body 2). The inclination angle θ (the angle between the beveled edge 3-2 and the reference plane of the box opening) is 35° to 65° (preferably 50°). The width of the beveled edge 3-2 is 14mm to 35mm (preferably 27mm) and is used for attaching the sealing strip 5.

[0034] The outer edge of the beveled edge 3-3 is connected to the inner edge of the beveled edge 3-2. The beveled edge 3-3 tilts inward toward the interior of the box body 2 (i.e., away from the top opening of the box body 2), forming a V-shaped structure (preferably at a 90° angle) between the beveled edge 3-2 and the beveled edge 3-3. This prevents the sealing strip 5 from being squeezed into the box during compression. The width of the beveled edge 3-3 is 6 mm to 10 mm.

[0035] The sealing strip 5 is placed or bonded to the oblique edge 3-2 of the retaining structure 3. In this embodiment, the top opening of the box body 2 is rectangular; the oblique edge 3-2 is formed by four straight segments; a linear sealing strip 5 is provided on each straight segment of the oblique edge 3-2. The four linear sealing strips 5 are glued together at their end-to-end junctions to prevent sealing defects.

[0036] like Figure 5 and 6 As shown, the annular rib structure 4 circumferentially extends and is shaped to match the beveled edge 3-2 of the retaining structure 3. The raised height of the annular rib is 7 mm to 25 mm, preferably 10 mm. The side of the annular rib structure 4 facing away from the center of the lid 1 (i.e., the outer side) forms an inclined sealing surface 4-1. The inclination angle φ of the inclined sealing surface 4-1 is 3° to 6° greater than the inclination angle θ of the beveled edge 3-2 of the retaining structure 3; in this embodiment, the inclination angle φ of the inclined sealing surface 4-1 is preferably 53°.

[0037] The annular convex rib structure 4 in the box cover 1 not only serves to resist the sealing strip 5 to form a sealing structure, but also strengthens the box cover 1 vertically and acts as a reinforcing rib to prevent the box cover 1 from bending and deformation during assembly.

[0038] The longitudinal cross-section of the sealing strip 5 is a rounded rectangular shape. In this embodiment, the dimensions of the sealing strip 5 are designed based on the opening dimensions of the housing 2 and the dimensions of the chute. The length of the sealing strip 5 is the same as the length of the chute on each side of the housing 2, and the width is the same as the width of the hypotenuse of the chute. The thickness of the sealing strip 5 should be slightly less than the height of the chute skirt 3-3, within a range of 3mm to 6mm. The sealing strip 5 is made of foam rubber, which has excellent elasticity and weather resistance. In this embodiment, the sealing strip 5 is available in two sizes: 490mm × 27mm × 5mm and 485mm × 27mm × 5mm. It is adhered to the longitudinal and width edges of the hypotenuse 3-2 of the retaining structure 3 of the housing 2.

[0039] Because it rests on the beveled edge 3-2 of the retaining structure 3, the sealing strip 5 assumes an inclined position. The top of the inclined sealing strip 5 abuts the bottom surface of the lid 1, forming a first sealing line. Because the inclination angle φ of the annular rib inclined sealing surface 4-1 is greater than the inclination angle θ of the beveled edge 3-2 of the retaining structure 3, the annular rib inclined sealing surface 4-1 gradually approaches the sealing strip 5 from top to bottom until the tip of the annular rib abuts the lower middle portion of the sealing strip 5, forming a second sealing line. This creates a double-line sealing structure, as detailed below:

[0040] After the sealing strip 5 is pasted on the inclined groove of the box body 2, the flat surface of the box lid 1 will first contact the edge of the sealing strip 5 during the closing process, forming the first line contact of the sealing structure. In the subsequent continuous closing process, the convex rib of the box lid 1 will press against the outer side of the sealing strip 5 to form the second line contact of the sealing structure, further strengthening the sealing effect. The double-line sealing structure during the assembly process also has advantages that the conventional surface contact sealing strip 5 sealing structure does not have: the conventional sealing structure presses the flat surface of the box lid 1 on the flat surface of the sealing strip 5 / sealing gasket to form a sealing effect, but the sealing strip 5 / sealing gasket is a flexible elastic structure, and the compression amount is not uniform at different places. Over time, various sizes of negative pressure areas will be formed in the surface contact area, making it extremely laborious to remove the box lid 1. The line contact sealing structure can better avoid the negative pressure area formed in the sealing surface. At the same time, the bell-mouth structure of the sealed structure of box 2 is particularly suitable for inverted junction boxes. It can not only play a conventional protective role, but also have a certain natural suction capacity when the cavity of box 2 undergoes climate cycles to form a negative pressure in the cavity, thereby reducing the impact of the negative pressure in the cavity.

[0041] In some embodiments, the horizontal portion 3-1 of the retaining structure 3 is provided with multiple first connection holes. A blind nut 3-5 is sealed and secured beneath each first connection hole. Second connection holes corresponding to the blind nuts 3-5 are provided on the edge of the lid 1. The lid 1 and the housing 2 are secured together using bolts and blind nuts 3-5. The use of blind nuts 3-5 prevents weak points in the seal between the lid 1 and the housing 2.

Claims

1. A junction box with a double-wire contact sealing structure, characterized in that: The invention comprises a box cover (1), a box body (2), a limiting structure (3), an annular convex rib structure (4) and a sealing strip (5); the limiting structure (3) is fixed at the opening of the box body (2); the annular convex rib structure (4) is fixed to the inner side surface of the box cover (1); the limiting structure (3) is provided with a surrounding oblique edge portion (3-2); the sealing strip (5) is arranged on the oblique edge portion (3-2) of the limiting structure (3); the outer side surface of the annular convex rib structure (4) is an inclined sealing surface (4-1); the sealing strip (5) is arranged between the oblique edge portion (3-2) of the limiting structure (3) and the inclined sealing surface (4-1) of the annular convex rib structure (4).

2. The junction box with a double-line contact sealing structure according to claim 1, characterized in that: The top of the sealing strip (5) abuts against the bottom surface of the box cover (1) to form a first sealing line; the bottom of the annular rib structure (4) abuts against the side of the sealing strip (5) away from the oblique edge portion (3-2) to form a second sealing line.

3. The junction box with a double-wire contact sealing structure according to claim 2, characterized in that: The inclination angle θ of the bevel portion (3-2) is 35° to 65°; the inclination angle φ of the inclined sealing surface (4-1) and the inclination angle θ satisfy the following relationship: 3°≤φ-θ≤6°.

4. The junction box with a double-wire contact sealing structure according to claim 1, characterized in that: The limiting structure (3) is annular and comprises a horizontal portion (3-1), a bevel portion (3-2) and an inclined groove skirt (3-3) connected in sequence from the inner side wall of the box body (2) toward the center of the box body (2); the outer peripheral contour of the horizontal portion (3-1) of the limiting structure (3) is connected to the inner side wall of the box body (2); the bevel portion (3-2) and the inclined groove skirt (3-3) form a V-shaped structure that constrains the sealing strip.

5. The junction box with a double-line contact sealing structure according to claim 4, characterized in that: The plane where the top opening outline of the box body (2) is located is used as the box opening reference plane; the horizontal portion (3-1) is parallel to the box opening reference plane and is 3mm to 8mm lower than the box opening reference plane; the width of the inclined groove skirt (3-3) is 6mm to 10mm.

6. The junction box with a double-line contact sealing structure according to claim 4, characterized in that: The width of the oblique edge portion (3-2) is 14mm~35mm.

7. The junction box with a double-wire contact sealing structure according to claim 6, characterized in that: The width of the sealing strip (5) is equal to the width of the oblique edge portion (3-2); the thickness of the sealing strip (5) is less than the width of the oblique groove skirt (3-3).

8. The junction box with a double-wire contact sealing structure according to claim 4, characterized in that: A downwardly folded flange structure (3-4) is provided at the outer periphery of the horizontal portion (3-1); the flange structure (3-4) is fixed to the inner side wall of the box body (2).

9. The junction box with a double-wire contact sealing structure according to claim 1, characterized in that: The height of the annular rib structure (4) is 7 mm to 25 mm.

10. The junction box with a double-wire contact sealing structure according to claim 1, characterized in that: The longitudinal section of the sealing strip (5) is a rounded rectangle.

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