Automotive ignition device comprising means for ensuring proper assembly thereof

Abstract

The present invention relates to a device comprising an insulating tube for assembling an automotive ignition system, wherein the physical structure thereof allows only one way of fitting the spring between the ignition coil and the spark plug, thereby preventing assembly errors, facilitating production line manufacturing and improving the quality of the part. The physical structure thereof, composed of at least one passage restriction and combined with a spring format, prevents incorrect assembly.

Description

“AUTOMOTIVE IGNITION DEVICE INCLUDING MEANS TO ENSURE ITS PROPER ASSEMBLY” Field of Invention

[0001] The present invention relates to an ignition device comprising means to ensure its proper assembly. Fundamentals of the Invention

[0002] As those versed in the subject know, the ignition coil is an automotive part used in combustion engines. It generates sufficient voltage to ignite the engine from the spark between the electrodes of a spark plug. The ignition coil transforms the battery's low voltage into a high-voltage output through electromagnetic induction, ensuring that the spark plugs receive a high-voltage pulse that ionizes the air-fuel mixture in the engine cylinders, creating a spark that ignites the mixture and initiates combustion.

[0003] The ignition system is basically formed by a transformer, consisting of two windings together with a ferromagnetic core, which transforms low voltage into high voltage, a spring that transfers the energy generated in the high voltage winding to the spark plug, the housing that surrounds the windings and the insulation tube that surrounds the entire spring structure.

[0004] The spring used in this system can be asymmetrical, with its ends having a larger diameter than the rest of the spring, ensuring that the spring does not move after fitting it into the structure. The insulation tube, also called a rubber boot or rubber sleeve, not only provides electrical insulation (due to its dielectric properties), but also physically surrounds the spring and protects it mechanically.

[0005] For quality reasons, it is necessary to ensure proper assembly of the ignition system to ensure that the spring does not shift within the insulation tube. This potential and unwanted shifting can create an air gap between the winding and the spring, generating harmful sparks within the tube. However, simply changing the diameter of the spring ends has not proven to be sufficiently efficient in preventing incorrect assemblies, since when assembling the system, said spring may be inserted on the opposite side (i.e., in the opposite direction) to that intended and, therefore, be unable to produce the desired effects and, worse, cause damage to the final product.

[0006] Patent document US2021335537 describes an ignition coil for an internal combustion engine that includes a fitting boot (insulation tube) with a length of orifice extending axially from the ignition coil, which has a plurality of small sections. These sections come in various shapes, not just circular (or annular), creating contact points with the spring at various corners, aiming to reduce possible spring displacement due to mechanical vibrations, in addition to providing greater resistance. However, its structure does not prevent incorrect assembly of the device; it merely ensures better stabilization of the spring ends within the insulation tube.

[0007] Patent document US6668810 describes a solution that uses a spring with its end diameter smaller than its central diameter in a tube with internal grooves, aiming to increase the spring's adhesion to the tube, reducing spring movement due to mechanical vibrations. However, as with the previous solution, there is no prevention of incorrect insertion of the spring into the device during assembly.

[0008] Patent document US2023313773 describes a solution that uses a spring whose winding density varies along its length. This spring configuration aims to prevent corona effects during winding and ensure ease of assembly. However, this solution does not solve the assembly quality problem, as incorrect assembly is still physically possible.

[0009] Patent document US2012186568 describes a solution in which the spark plug has a contact region with the ignition coil spring, this region having a recess surrounded by a closed annular wall portion to receive the contact segment of the ignition coil spring. ignition. This configuration is intended to facilitate system assembly. However, the solution also does not prevent incorrect assembly if the spring is inserted in the wrong direction.

[0010] Thus, and although the solution of these documents may be functional for the purposes for which they were made possible, it is observed that it is possible to optimize them in terms of quality assurance in the assembly process, through a sufficiently robust, efficient, reliable, simple and low-cost solution.

[0011] Based on this scenario, aiming to mitigate the technical limitations observed in the presented patent documents, the present invention arises. Objectives of the Invention

[0012] Thus, the present invention has as its main objective to reveal an insulation tube for assembling an automotive ignition system in which, based on its physical construction, it allows only one way of assembling the spring between the transformer and the spark plug.

[0013] Additionally, it is an objective of the present invention to provide an insulation tube for assembling an automotive ignition system that allows the reception or, in other words, the insertion of a spring in only one direction during assembly.

[0014] Furthermore, the present invention aims to reveal an insulation tube for assembling an automotive ignition system that allows greater ease (or practicality) of assembly on a production line.

[0015] Furthermore, the objective of the present invention is to present an insulation tube for assembling an automotive ignition system that allows for better system quality, since its structure physically prevents differences between produced parts caused by incorrect assembly. Summary of the Invention

[0016] All the above-mentioned objectives are achieved by means of an automotive ignition device comprising means for ensuring its proper assembly, said ignition device being of the type that includes at least one insulation tube that surrounds at least one spring, wherein in a first portion of the insulation tube a first passage restriction is provided, characterized in that said first passage restriction comprises an inner diameter of the first passage restriction smaller than an outer diameter of the first end of at least a portion of a first end of the spring, so that said passage restriction restricts, at least partially, the passage of the first end of the spring.

[0017] Additionally, an automotive ignition device is provided as previously indicated, in that a second passage restriction is provided in a second portion of the insulation tube. Also, in accordance with the present invention, said spring comprises a main spring portion extending between the first end and a second end.

[0018] Furthermore, the first passage restriction inner diameter of the entire first passage restriction is larger than the respective spring portion outer diameter of the entire spring portion and second end outer diameter of the entire second spring end, so that the spring portion and the second spring end are able to pass through said first passage restriction during the assembly of the spring in the insulation tube.

[0019] Finally, the aforementioned automotive ignition device is such that the second end outer diameter is smaller than a second passage restriction inner diameter, so that the second end is able to pass through the second passage restriction. Brief Description of the Figures

[0020] The preferred embodiment of the invention in question is described in detail based on the listed figures, which:

[0021] Figure 1 illustrates, in section, the ignition coil assembly formed by the insulation tube, the asymmetrical spring, the spark plug and the transformer associated with its external coating, according to the present invention.

[0022] Figure 2 illustrates a longitudinal sectional view of the insulation tube according to the present invention.

[0023] Figure 3 illustrates a longitudinal cross-sectional view of the insulation tube of the present invention, according to an alternative embodiment.

[0024] Figure 4 illustrates an asymmetric spring in relation to a cross-section, according to the present invention, to be mounted on the insulation tube of the present invention, with the end of the spring facing the high voltage output of the transformer and the end of the spring facing the spark plug being highlighted.

[0025] Figure 5 illustrates a longitudinal cross-sectional view of the insulation tube, highlighting the internal diameters of the first passage restriction and the second passage restriction.

[0026] Figure 6 illustrates a longitudinal cross-sectional view of the insulation tube, highlighting the outer diameters of the first end of the spring, the second end of the spring, and a portion of the spring. Detailed Description of the Invention

[0027] To achieve the objectives described above, the present invention relates to an automotive ignition device that includes, among other elements, an insulation tube 4, also called a rubber boot, which surrounds the spring 3 of the automotive ignition device. Said insulation tube 4, in addition to having an electrical and thermal protective function, also prevents excessive movement of the spring 3 within the device and provides means to ensure the correct fit of the spring 3 within the assembly, thus preventing unwanted sparks and, consequently, malfunctions in the system.

[0028] This ignition device is composed of at least one transformer 1, responsible for generating high ignition voltage, associated with (or, in other words, housed in) an encapsulation 1.1 that guarantees electrical and thermal protection, at least one spark plug 2, at least one spring 3 surrounded by the insulation tube 4, wherein in a portion of the insulation tube 4, preferably that associated with the high voltage output of the transformer 1, there is a first passage restriction 4.1, such as an internal flange.

[0029] This first passage restriction 4.1 is primarily responsible for preventing spring 3 from being inserted the wrong way during ignition device assembly. In other words, it allows only one way to assemble spring 3 between transformer 1 and spark plug 2, ensuring error-proof (poka-yoke) assembly. This is because this first passage restriction 4.1 comprises an inner diameter of the first passage restriction d4.1 smaller than an outer diameter of the first end 3.1 of a first end 3.1 of spring 3, so that said first end 3.1 of spring 3, when assembling the latter, does not pass through (at least not entirely) said first restriction 4.1.

[0030] Additionally and preferably, in another portion of the insulation tube 4, distal to the first portion of the insulation tube, that is, that associated with the spark plug 2, there is a second passage restriction 4.2 provided to prevent possible undue displacement of the spring 3, either during assembly or during use of the device in operation, which may occur due to vibrations and mechanical shocks. This second passage restriction 4.2 does not directly prevent incorrect assembly of the system, being only an additional support to protect against undue movement.

[0031] Figure 4 shows spring 3 which, being made of a highly electrically conductive material (such as stainless steel, for example), helps transmit energy from transformer 1 to spark plug 2.

[0032] The spring 3 has an asymmetrical shape in relation to a cross-sectional axis (or section), and its first end 3.1, facing the transformer 1, has a first end outer diameter d3.1 larger than the rest of the spring 3, so that, during the assembly of the spring 3 in the insulation tube 4, said first end 3.1 does not pass through any of the first and second passage restrictions 4.1, thus preventing spring 3 from being inserted, during its assembly, on the opposite side. This guarantee prevents some electrical connections from being lost (the connections between the ignition coil and spring 3 and between spring 3 and the high-voltage terminal of spark plug 2) and premature wear of the material connecting transformer 1 to spring 3, thus avoiding possible inappropriate electrical contact.

[0033] On the other hand, the second end 3.2 of the spring 3, facing the spark plug 2, has a second end outer diameter d3.2 smaller than the rest of the spring 3 so that the second end 3.2 is able to pass through the second passage restriction 4.2. For the sake of explanation, it should be mentioned that the first end 3.1 having a first end outer diameter d3.1 larger than the first passage restriction inner diameter d4.1 of the first passage restriction 4.1 means that at least one of the turns of the first end 3.1 has an outer diameter larger than the inner diameter of at least a portion of the first passage restriction 4.1, so that it is impossible for the first end 3.1 to pass through the first passage restriction 4.1 even when trying to assemble the spring 3 from the inverted side during assembly thereof in the insulation tube 4.

[0034] Said first passage restriction 4.1 is not necessarily annular, but can take several different shapes, for example, frustoconical. That is, the inner diameter of the first passage restriction d4.1 can be constant or variable along the length of the first passage restriction 4.1 . It is worth noting that the fundamental premise is that the passage restriction 4.1 comprises at least one cross-section whose inner diameter is smaller than the outer diameter of at least one turn of the first end 3.1 .

[0035] Additionally, in the present invention, in spring 3, in at least one of its turns at the second end 3.2, associated with the spark plug, all turns have the second end outer diameter d3.2 smaller than the first-pass restriction inner diameter d4.1 (along its entire length).

[0036] Just like the first passage restriction 4.1, the second passage restriction 4.2 is also not necessarily annular and, therefore, can assume several different shapes, for example frusto-conical. The fundamental premise is that at least one of the turns of the second end 3.2 has a second end outer diameter d3.2 slightly larger than the second passage restriction inner diameter d4.2 of at least a portion (section) of the second passage restriction 4.2.

[0037] Also, according to the present invention, the size of the inner diameter of the first passage restriction 4.1 associated with the transformer side 1 is independent of the size of the inner diameter of the second passage restriction 4.2.

[0038] It is important to emphasize that the above description is solely intended to describe, by way of example, the particular embodiment of the invention in question. Therefore, it becomes clear that modifications, variations, and constructive combinations of the elements that perform the same function in substantially the same way to achieve the same results remain within the scope of protection delimited by the appended claims.

Claims

CLAIMS 1. Automotive ignition device comprising means for ensuring its proper assembly, said ignition device being of the type that includes at least one insulation tube (4) surrounding at least one spring (3), wherein in a first portion of the insulation tube (4) a first passage restriction (4.1) is provided, CHARACTERIZED by the fact that said first passage restriction (4.1) comprises a first passage restriction inner diameter (d4.1) smaller than a first end outer diameter (d3.1) of at least a portion of a first end (3.1) of the spring (3), so that said passage restriction (4.1) restricts, at least partially, the passage of the first end (3.1) of the spring (3).

2. Automotive ignition device, according to claim 1, CHARACTERIZED by the fact that in a second portion of the insulation tube (4) there is a second passage restriction (4.2).

3. Automotive ignition device, according to claim 1, CHARACTERIZED by the fact that: said spring (3) comprises a main spring portion (3.3) extending between the first end (3.1) and a second end (3.2); the first passage restriction inner diameter (d4.1) of the entire first passage restriction (4.1) is larger than respective spring portion outer diameter (d3.3) of the entire spring portion (3.3) and second end outer diameter (d3.2) of the entire second end (3.2) of the spring (3), so that the spring portion (3.3) and the second end (3.2) of the spring (3) are able to pass through said first passage restriction (4.1) during assembly of the spring (3) in the insulation tube (4).

4. Automotive ignition device, according to claims 2 and 3, CHARACTERIZED by the fact that: the second end outer diameter (d3.2) is smaller than a second passage restriction inner diameter (d4.2), so that the second end (3.2) is able to cross the second passage restriction (4.2).

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