Spark plug spark gap adjustment device, spark plug spark gap adjustment method

Abstract

The present invention provides a spark plug spark gap adjustment device for a spark plug having a skirt-type outer electrode, which has a relatively simple configuration and can securely hold and fix the spark plug while accurately adjusting multiple adjustment points one by one. [Solution] The device comprises a fixed base and a gap adjustment part coupled to the upper part of the fixed base so as to be circumferentially rotatable, wherein the fixed base has a grounding part, a spark plug mounting part arranged cylindrically above the grounding part and having a spark plug installed inside, and a plurality of fixing screws that press the spark plug installed inside through a through hole in the spark plug mounting part, and the gap adjustment part has an adjustment screw that presses the gap adjustment portion of the spark plug installed inside through a through hole in the gap adjustment part.

Description

Technical Field

[0001] The present invention relates to a configuration and method of a spark gap adjusting device for adjusting a spark gap of a spark plug, and particularly relates to a technique effective when applied to a spark plug having a skirt-type outer electrode.

Background Art

[0002] A spark plug is a device that serves as a lighter to electrically ignite a mixture of gasoline and air in an internal combustion engine such as an engine. Depending on a wide range of applications, such as for engines of automobiles and motorcycles, for jet engines of aircraft, for gas turbine engines of cogeneration systems and emergency power sources, various types of spark plugs are used.

[0003] In a spark plug, a high voltage is applied between electrodes provided with an appropriate gap to cause a spark discharge and ignite the compressed air-fuel mixture. The voltage supplied to the spark plug is generated by an ignition coil or an ignition device. The center electrode of the spark plug is connected to the ignition coil or the like, and the ground electrode (or outer electrode) is brought into contact with the engine block to be grounded.

[0004] The most common spark plugs for automobile and motorcycle engines have a structure in which an L-shaped outer electrode (ground electrode) is arranged outside a convex center electrode. However, for example, in the spark plug for a gas engine of a generator, since reliable starting performance and reliability are required, a structure in which a skirt-type outer electrode (ground electrode) is arranged outside a center electrode having a certain area is adopted to generate a stronger spark.

[0005] On the other hand, the gap between the center electrode and the outer electrode (ground electrode) is called a "spark gap" (also simply called a "gap" or a "discharge gap" etc.), and since it greatly affects the ignition timing and combustion efficiency of the engine, it needs to be adjusted to an appropriate value. If the spark gap is too wide or too narrow, ignition is likely to be insufficient, which may lead to engine misfire.

[0006] As background technology for this field, for example, there is technology such as that described in Patent Document 1. Patent Document 1 discloses "a spark plug that allows the distance between the center electrode and the ground electrode (discharge gap) to be checked from the outside, and that allows for the checking of whether the discharge gap is widening or not, and the adjustment of the discharge gap to an appropriate distance while checking what the distance of the discharge gap is." [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2011-196268 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] By the way, in the conventional spark gap adjustment process for spark plugs with skirt-type outer electrodes, a special tool equipped with a gap gauge at its tip is used. However, this tool lacks a function to hold the spark plug, and it is difficult to insert the gap gauge at the tip of the tool, resulting in poor work efficiency.

[0009] Furthermore, with spark plugs that have a skirt-shaped outer electrode, it is necessary to adjust two spark gaps simultaneously, which can easily lead to uneven spark gaps.

[0010] Furthermore, when adjusting the spark gap using the dedicated tool described above, changing the adjustment value requires replacing and reattaching the gap gauge at the tip, making it difficult to change the adjustment value.

[0011] The above-mentioned Patent Document 1 deals with a spark plug structure in which an L-shaped outer electrode (ground electrode) is arranged outside a convex central electrode, and does not take into consideration the above-mentioned problems at all.

[0012] Therefore, the object of the present invention is to provide a spark plug spark gap adjustment device and a spark plug spark gap adjustment method using the same, which, with a relatively simple configuration, can securely hold and fix the spark plug while accurately adjusting multiple adjustment points one by one. [Means for solving the problem]

[0013] To solve the above problems, the spark plug spark gap adjustment device of the present invention comprises a fixed base and a gap adjustment unit coupled to the upper part of the fixed base so as to be circumferentially rotatable, wherein the fixed base has a grounding portion, a spark plug installation portion arranged cylindrically above the grounding portion and for installing a spark plug inside, and a plurality of fixing screws that press the spark plug installed inside through a through hole in the spark plug installation portion, and the gap adjustment unit has an adjustment screw that presses the gap adjustment portion of the spark plug installed inside through a through hole in the gap adjustment unit.

[0014] Furthermore, the spark plug spark gap adjustment method of the present invention includes the steps of: (a) installing a spark plug inside the spark plug mounting portion of the fixed base; (b) after step (a), attaching a gap adjustment portion to the upper part of the fixed base; (c) after step (b), pressing and fixing the spark plug with a fixing screw; (d) after step (c), rotating the gap adjustment portion in the circumferential direction while visually checking from above the gap adjustment portion to align the position of the gap adjustment portion of the spark plug with the adjustment screw; (e) after step (d), fixing the position of the gap adjustment portion relative to the fixed base with a set screw; and (f) after step (e), setting a gap of a predetermined thickness. The method is characterized by including the steps of: (g) inserting a gauge into the gap of the gap adjustment location and pressing the gap adjustment location with the adjustment screw; (f) after step (g), removing the gap gauge from the gap and loosening the adjustment screw to release the pressure on the gap adjustment location; (h) after step (g), loosening the fixing screw to release the pressure on the spark plug; (i) after step (h), loosening the set screw and removing the gap adjustment part from the upper part of the fixing base; and (j) after step (i), inserting a projection into the through hole of the ground portion of the fixing base and pushing up the spark plug with the projection to remove it from the spark plug installation portion. [Effects of the Invention]

[0015] According to the present invention, a spark plug spark gap adjustment device and a spark plug spark gap adjustment method using the same can be realized for a spark plug having a skirt-type outer electrode, with a relatively simple configuration that can securely hold and fix the spark plug while accurately adjusting multiple adjustment points one by one.

[0016] This contributes to improving the quality and reducing the time required for spark gap adjustment work, preventing engine ignition problems, and preventing damage to spark plugs while extending their lifespan.

[0017] Problems, configurations, and effects other than those described above will be clarified by the descriptions of the following embodiments.

Brief Explanation of Drawings

[0018] [Figure 1] It is a diagram showing a schematic configuration of a spark plug spark gap adjusting device according to Example 1 of the present invention. [Figure 2A] It is a view (top view) taken in the direction of arrow A - A' in FIG. 1. [Figure 2B] It is a view (bottom view) taken in the direction of arrow B - B' in FIG. 1. [Figure 3] It is a diagram showing a schematic configuration of a spark plug spark gap adjusting device according to Example 2 of the present invention. [Figure 4] It is a diagram showing the structure of the fixed pedestal 2 in FIG. 1. [Figure 5] It is a diagram showing the structure of the gap adjustment part 3 in FIG. 1. [Figure 6] It is a diagram showing an example of the fixing screw 7 and the adjusting screw 9 in FIG. 1. [Figure 7] It is a diagram showing an example of the set screw 11 in FIG. 1. [Figure 8] It is a diagram showing the structure of the deep socket 12 in FIG. 1. [Figure 9A] It is a diagram showing an example of a spark plug targeted by the present invention. [Figure 9B] It is an enlarged view of part C in FIG. 9A. [Figure 9C] It is a view taken in the direction of arrow D - D' in FIG. 9A.

Modes for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, the same components are denoted by the same reference numerals, and detailed descriptions of overlapping parts will be omitted.

Examples

[0020] First, with reference to Figures 9A to 9C, a spark plug having a skirt-type outer electrode, which is the subject of the present invention, will be described. Figure 9A is a diagram showing an example of a spark plug that is the subject of the present invention. Figure 9B is an enlarged view of part C in Figure 9A. Figure 9C is a view taken along the line D-D' in Figure 9A.

[0021] As shown in Figure 9A, the spark plug 14, which has a skirt-shaped outer electrode, has a terminal 19 at one end of the spark plug body 18, and a fixing screw pressing surface 16, a threaded portion 20, and an outer electrode (skirt) 21 at the other end. A plug cord for receiving high voltage current is connected to the terminal 19, and the voltage generated by the ignition coil, etc., is supplied. The fixing screw pressing surface 16 is the surface against which the fixing screw 7, which will be described later, is pressed when adjusting the spark gap. The threaded portion 20 is the fixing screw portion when attaching the spark plug 14 to the engine housing, etc. The outer electrode (skirt) 21 is a ground electrode relative to the center electrode 25, which will be described later.

[0022] As shown in Figure 9B, the outer electrode (skirt) 21 is provided with holes 22a, 22b, and 22c and notches 23 for adjusting the spark gap. The holes 22a, 22b, and 22c and the notches 23 are arranged at four locations around the outer electrode (skirt) 21 at 90° intervals. When adjusting the spark gap, the pressing portion 24 of the outer electrode (skirt) 21 is pushed inward using the adjustment screw 9, which will be described later.

[0023] As shown in Figure 9C, a central electrode 25 with a certain area is positioned inside the outer electrode (skirt) 21, separated by a gap. At each gap adjustment point, the notch 23 is tilted by pressing the pressing part 24 with the adjustment screw 9 (described later), bringing it closer to the central electrode 25 and adjusting the spark gap. In the example in Figure 9C, there are a total of four gap adjustment points located at 0°, 90°, 180°, and 270° positions in the circumferential direction of the outer electrode (skirt) 21, at 90° intervals.

[0024] When adjusting the spark gap, the adjustment screw 9 is used to press the pressure part 24 of the gap adjustment point, and the gap is checked with a gap gauge. This process is repeated until the desired spark gap is achieved. Note that each gap adjustment point will try to return to its original shape due to elastic deformation, but this should be taken into consideration when adjusting to the desired spark gap.

[0025] As shown in Figure 9C, adjusting the spark gap requires precise adjustment, for example, to about 0.35 mm. Failure to properly adjust the gap may lead to deformation or damage to the outer electrode (skirt) 21.

[0026] Next, with reference to Figures 1 to 2B and Figures 4 to 8, a spark plug spark gap adjustment device according to Embodiment 1 of the present invention and a method for adjusting the spark plug spark gap using the same will be described. Figure 1 is a diagram showing the schematic configuration of the spark plug spark gap adjustment device 1 of this embodiment. Figure 2A is a view (top view) in the direction of arrow A-A' in Figure 1. Figure 2B is a view (bottom view) in the direction of arrow B-B' in Figure 1. Figure 4 is a diagram showing the structure of the fixing base 2 in Figure 1. Figure 5 is a diagram showing the structure of the gap adjustment part 3 in Figure 1. Figure 6 is a diagram showing an example of the fixing screw 7 and adjustment screw 9 in Figure 1. Figure 7 is a diagram showing an example of the set screw 11 in Figure 1. Figure 8 is a diagram showing the structure of the deep socket 12 in Figure 1.

[0027] As shown in Figure 1, the spark plug spark gap adjustment device 1 of this embodiment mainly comprises a fixed base 2 and a gap adjustment unit 3. The gap adjustment unit 3 is mounted on the upper part of the fixed base 2 so as to be rotatable in the circumferential direction. The fixed base 2 has a grounding portion 4 that is grounded to the floor surface 15, a spark plug installation portion 5 which is cylindrically arranged above the grounding portion 4 and in which a spark plug 14 is installed, and a plurality of fixing screws 7 which press the spark plug 14 installed inside through through holes 6 provided in the spark plug installation portion 5.

[0028] The gap adjustment section 3 has an adjustment screw 9 that presses against the gap adjustment point of the spark plug 14 installed inside it, via a through hole 8 provided in the gap adjustment section 3. The fixing base 2 also has a set screw 11 that fixes the position of the gap adjustment section 3 via a through hole 10 provided in the spark plug installation section 5.

[0029] As shown in Figures 2A and 5, the gap adjustment section 3 is provided with four through holes 8 at positions corresponding to the gap adjustment points in its circumferential direction. The spark gap is adjusted by pressing the pressing portion 24 of the outer electrode (skirt) 21 with the adjustment screw 9 through the through holes 8.

[0030] As shown in Figures 2B and 4, the grounding portion 4 of the fixed base 2 is provided with a through hole 13. After the adjustment work is completed, the spark plug 14 can be pushed up through the through hole 13 with a projection or the like to remove the spark plug 14 from the spark plug spark gap adjustment device 1.

[0031] As shown in Figure 6, the fixing screw 7 and the adjustment screw 9 are screws with a spherical R-shaped tip at the pressing position. This is to prevent damage to the spark plug 14 when the fixing screw 7 and the adjustment screw 9 press against the spark plug 14. On the other hand, as shown in Figure 7, the set screw 11 is intended to firmly press against the gap adjustment part 3 to prevent it from moving, so a screw without a spherical tip is used.

[0032] As shown in Figure 8, the deep socket 12 has a hollow shape, and the spark plug 14 is installed so as to fit into the hollow of the deep socket 12 which is located within the spark plug installation section 5. By placing the deep socket 12, the spark plug 14 can be securely held within the spark plug installation section 5.

[0033] Using Figure 1, we will explain the method for adjusting the spark plug spark gap using the spark plug spark gap adjustment device 1.

[0034] First, the spark plug 14 is installed inside the spark plug mounting section 5. Next, the gap adjustment section 3 is attached to the top of the fixing base 2. Then, the spark plug 14 is pressed and fixed with the fixing screws 7. When the spark plug 14 is installed in the spark plug mounting section 5, there is a gap, so there is some looseness. In order to accurately adjust the spark gap, it is necessary to "center" the spark plug 14 so that its central axis aligns with the central axis of the spark plug mounting section 5. To facilitate this adjustment, the spark plug 14 is fixed by pressing the fixing screw pressing surface 16 of the spark plug 14 with multiple fixing screws 7 from multiple horizontal angles. In practice, the pressing angles at this time are preferably 3 directions (120° pitch) or 4 directions (90° pitch). Next, the gap adjustment section 3 is rotated circumferentially while visually checking from above the gap adjustment section 3 to align the position of the gap adjustment point of the spark plug 14 with the adjustment screw 9. Next, the position of the gap adjustment section 3 relative to the fixing base 2 is fixed with the set screw 11.

[0035] Next, a gap gauge of the specified (desired) thickness is inserted into the gap at the gap adjustment point, and the gap adjustment point (pressing part 24) is pressed with the adjustment screw 9 to adjust the spark gap to the desired width. Then, the gap gauge is removed from the gap, and the adjustment screw 9 is loosened to release the pressure on the gap adjustment point. Next, the fixing screw 7 is loosened to release the pressure on the spark plug 14. Next, the set screw 11 is loosened, and the gap adjustment part 3 is removed from the top of the fixing base 2. Finally, a projection is inserted into the through hole 13 of the grounding part 4, and the spark plug 14 is pushed up with the projection and removed from the spark plug spark gap adjustment device 1. This is to prevent the worker from accidentally touching the notch 23 of the outer electrode (skirt) 21, which is easy to grasp with the fingers, when removing the spark plug 14 from the spark plug spark gap device 1 after gap adjustment.

[0036] As described above, the spark plug spark gap adjustment device 1 of this embodiment allows the spark plug 14 to be installed and held in a vertical position by providing a spark plug installation section 5 inside the cylindrical part of the fixed base 2. Furthermore, the spark plug 14 can be securely fixed after being centered by tightening it with fixing screws 7 from multiple directions in the circumferential direction at, for example, 120° intervals. In addition, the gap adjustment section 3 can be rotated in the circumferential direction to set the adjustment screw 9 to an appropriate position (any pressing position).

[0037] Furthermore, the operator can adjust the spark gap by inserting a gap gauge into the spark gap with one hand and tightening the adjustment screw 9 with the other hand. In addition, because the structure is designed to apply appropriate pressure to each gap adjustment point, the possibility of deformation of the outer electrode (skirt) 21 or breakage due to bending of the center electrode 25 during adjustment work can be reduced. This also improves the workability and accuracy of the spark gap adjustment work, resulting in an appropriate spark gap and preventing engine malfunctions related to ignition.

[0038] As shown in Figure 9B, the gap adjustment points of the spark plug 14 are notches 23 arranged at 90° intervals on the outer electrode (skirt) 21. When adjusting the gap, the notches 23 are tilted and brought closer to the central electrode 25 by pressing the pressing part 24 with the adjustment screw 9 in point contact, thereby adjusting the gap. Therefore, the following conditions must be met.

[0039] (1) Because the pressing area is small, it is necessary to reduce the contact area when pressing, and the tip of the adjustment screw 9 is rounded to make it spherical, thereby reducing the contact area. (2) In order to avoid damaging the outer electrode (skirt) 21, there should be no edge on the tip of the adjustment screw 9. Therefore, it is necessary to eliminate the edge by rounding the tip of the adjustment screw 9 to make it spherical.

[0040] Therefore, in the spark plug spark gap adjustment device 1 of this embodiment, screws with a spherical R-shaped tip are used for the fixing screw 7 and the adjustment screw 9.

[0041] Furthermore, after rotating the gap adjustment unit 3 in the circumferential direction and aligning the adjustment screw 9 to the appropriate position (any pressing position), it is necessary to fix the position so that the gap adjustment unit 3 does not rotate in the circumferential direction. If the operator accidentally touches the gap adjustment unit 3 during the gap adjustment process, the gap adjustment unit 3 will rotate, so it is necessary to fix its position so that the pressing position of the adjustment screw 9 does not change.

[0042] Therefore, in the spark plug spark gap adjustment device 1 of this embodiment, rotation of the gap adjustment part 3 is prevented by pressing the gap adjustment part 3 against the upper part of the fixed base 2 with a set screw 11 through the through hole 10 of the spark plug mounting part 5. The set screw 11 is a screw that does not have a spherical shape at the tip, as the purpose is to press firmly. [Examples]

[0043] Referring to Figure 3, the spark plug spark gap adjustment device according to Embodiment 2 of the present invention will be described. Figure 3 is a diagram showing the schematic configuration of the spark plug spark gap adjustment device of this embodiment.

[0044] As explained in Example 1, a commercially available, standard-sized deep socket 12 can be installed inside the cylindrical part of the fixed base 2 to form the spark plug mounting section 5. In this case, it is simpler and cheaper to use than to design and manufacture the spark plug mounting section 5 to match the shape and dimensions of the spark plug 14 to be installed.

[0045] However, when using a standard-sized deep socket 12, a problem may occur where the pressing position of the fixing screw 7 and the height of the fixing screw pressing surface 16 of the spark plug 14 differ, as shown in the left diagram of Figure 3. This problem occurs because the dimensions of the standard-sized deep socket 12 do not match the shape of the spark plug 14 to which it is installed, and it does not occur when the spark plug mounting section 5 is manufactured to match the shape and dimensions of the spark plug 14 in its unused state. Furthermore, even if the spark plug mounting section 5 is manufactured as a designed part, this problem may occur if the height of the spark plug 14 changes compared to its unused state due to aging or wear after use.

[0046] Therefore, as shown in the right-hand diagram of Figure 3, in the spark plug spark gap adjustment device 1 of this embodiment, a spacer 17 for height adjustment is installed inside the spark plug installation section 5 to match the pressing position of the fixing screw 7 with the height position of the fixing screw pressing surface 16 of the spark plug 14 installed inside. The conditions for the spacer 17 are that it "can be installed inside the spark plug installation section 5" and "does not become an obstruction when installing the spark plug 14 in the spark plug installation section 5". After understanding the dimensions of the different heights, a new one that satisfies the above conditions is manufactured or an off-the-shelf product is used as a substitute. (Example: Using multiple sealing washers stacked together when installing the spark plug 14) Furthermore, when adjusting the height with spacer 17, it is necessary to check each time whether the pressing position of the adjustment screw 9 matches the height of the pressing portion 24 of the outer electrode (skirt) 21 shown in Figure 9B.

[0047] The spacer 17 for adjusting the height position may also be fixed to the inner wall of the spark plug mounting section 5 with adhesive or the like.

[0048] According to the spark plug spark gap adjustment device 1 of this embodiment described above, when holding the spark plug 14 in a vertical position, the pressing position of the fixing screw 7 and the height of the fixing screw pressing surface 16 of the spark plug 14 can be matched.

[0049] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are described in detail to make the present invention easier to understand, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. In addition, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations. [Explanation of Symbols]

[0050] 1…Spark plug spark gap adjustment device 2…Fixed base 3…Gap adjustment section 4...Grounding part 5…Spark plug installation area 6…Through hole (for fixing screw) 7… Fixing screws 8…Through hole (for adjustment screw) 9... Adjustment screw 10… (For set screws) Through holes 11…Set screw 12... Deep socket 13…Through-hole (on the bottom) 14... Spark plug 15…Floor surface 16…Fixing screw pressing surface 17…Spacer 18... Spark plug body 19… Terminal 20...Screw part 21…Outer electrode (skirt) 22a, 22b, 22c…hole 23... Notch 24... Pressing part 25...Center electrode.

Claims

1. Fixed base and A gap adjustment unit is coupled to the upper part of the fixed base so as to be rotatable in the circumferential direction, Equipped with, The aforementioned fixed base has a ground contact portion and An ignition plug mounting section is provided, which is arranged in a cylindrical shape above the aforementioned grounding section and has an ignition plug installed inside, The spark plug mounting section has multiple fixing screws that press against the spark plug installed inside through the through hole, The spark plug spark gap adjustment device is characterized in that the gap adjustment part has an adjustment screw that presses against the gap adjustment part of the spark plug installed inside through a through hole in the gap adjustment part.

2. A spark plug spark gap adjustment device according to claim 1, A spark plug spark gap adjustment device characterized in that the fixing screw and the adjustment screw have spherically processed tips at the pressing position.

3. A spark plug spark gap adjustment device according to claim 1, A spark plug spark gap adjustment device characterized by installing a height-adjusting spacer inside the spark plug mounting section, thereby aligning the pressing position of the fixing screw with the height of the fixing screw pressing surface of the spark plug installed inside.

4. A spark plug spark gap adjustment device according to claim 1, The spark plug spark gap adjustment device is characterized in that the fixed base is provided with a set screw that fixes the position of the gap adjustment part through a through hole in the spark plug installation part.

5. A spark plug spark gap adjustment device according to claim 1, The spark plug spark gap adjustment device is characterized in that the grounding portion has a through hole for pushing up the spark plug installed inside with a projection and removing it from the spark plug spark gap adjustment device.

6. The following steps are included in the method for adjusting the spark plug spark gap: (a) Step of installing the spark plug inside the spark plug installation section of the fixed base, (b) After step (a), a step of attaching the gap adjustment part to the upper part of the fixed base, (c) After step (b), the spark plug is pressed and secured with a fixing screw. (d) After step (c), rotate the gap adjustment part in the circumferential direction while visually checking from above the gap adjustment part, and align the position of the gap adjustment point of the spark plug with the adjustment screw. (e) After step (d), the step of fixing the position of the gap adjustment part with respect to the fixing base using a set screw, (f) After step (e), insert a gap gauge of a predetermined thickness into the gap of the gap adjustment location and press the gap adjustment location with the adjustment screw, (g) After step (f), remove the gap gauge from the gap and loosen the adjustment screw to release the pressure on the gap adjustment point. (h) After step (g) above, the step of loosening the fixing screw to release the pressure on the spark plug, (i) After step (h) above, loosen the set screw and remove the gap adjustment part from the top of the fixed base, (j) After step (i), insert the projection into the through hole of the ground portion of the fixed base, and push up the spark plug with the projection to remove it from the spark plug mounting portion.

Images