JP2021032109A - Inspection port oil seal structure - Google Patents

Abstract

To provide an inspection port oil seal structure which can make the ooze-out of oil inconspicuous by further reducing a depth at which a gasket damages a periphery of an inspection port or a range of the damage when co-fastening an inspection port plug detachably attached to the inspection port formed at an internal combustion engine and the gasket.SOLUTION: An inspection port oil seal structure has: an inspection port formed at an internal combustion engine, and formed with a female screw part at an internal peripheral face while having a circular shape for making the outside and the inside of the internal combustion engine communicate with each other; a male screw part screwed into the female screw part of the inspection port; an inspection port plug having a plug head part arranged at a tip of the male screw part, and blocking the inspection port; and a ring-shaped gasket sandwiched between a periphery of the inspection port and the plug head part of the inspection port plug, and sealing the inspection port. The inspection port is formed at a face along a vertical direction of the internal combustion engine in a position different from an oil pan of the internal combustion engine, and the gasket is applied with a resin coating on its surface.SELECTED DRAWING: Figure 3

Description

The present invention relates to an inspection port oil seal structure.

Generally, in an internal combustion engine using a piston (reciprocating engine), a timing chain for driving a camshaft that opens and closes an exhaust valve and an intake valve and a tensioner that applies tension to the timing chain are arranged in front of the internal combustion engine. There is. The tensioner is provided with a rod that can be expanded and contracted to apply tension to the timing chain.

During maintenance or replacement of timing chains, work tools are used to keep the length of the rod protruding from the tensioner appropriate in order to facilitate the work. Since the operator uses this work tool from the outside of the internal combustion engine, a circular inspection port is provided on the front surface of the internal combustion engine. A bolt-shaped inspection port plug having a male screw portion and a plug head portion and a gasket are detachably provided in this inspection port.

This inspection port is generally provided on a cover member made of metal such as aluminum that covers a part of the front surface of the internal combustion engine, and a female screw is provided on the inner peripheral surface of the inspection port. The male screw part is screwed in. During normal operation (other than during maintenance or replacement), the inspection port plug and gasket are fastened together with the inspection port, and the plug head of the inspection port plug crushes the ring-shaped metal gasket to seal the inspection port. This prevents oil from leaking from the inside of the internal combustion engine.

Here, the conventional inspection port oil seal structure and the procedure for tightening the inspection port plug and the gasket together with the inspection port will be described with reference to FIGS. 6 to 8. FIG. 6 shows a cross-sectional view of the inspection port 144 with the inspection port plug 120 and the gasket 130 fastened together, and FIG. 7 shows a cross-sectional view of VII-VII of FIG. Note that, for the sake of explanation, FIG. 7 shows that the inner peripheral radius R130N, which is the radius of the inner diameter of the gasket 130, is much larger than the actual radius with respect to the male screw radius R124, which is the radius of the male screw portion 124 of the inspection port plug 120. An enlarged example is shown. Further, in FIG. 8, when the inspection port plug 120 and the gasket 130 are fastened together and the gasket 130 is rotated around the inspection port plug 120, the mounting surface 142 around the inspection port 144 is damaged and adhesive wear (muscle wear) occurs. An example of a gasket region (outer gasket region 130S, inner gasket region 130U), which is a region, is shown.

As shown in FIG. 6, the conventional inspection port oil seal structure 110 includes a cover member 140, an inspection port plug 120, and a gasket 130. The cover member 140 is made of aluminum or the like, and an inspection port 144, which is a through hole having a central axis 144J formed in a substantially horizontal direction, is provided on a mounting surface 142 along a substantially vertical direction. A female screw portion 146 is formed on the inner peripheral surface of the inspection port 144.

The inspection port plug 120 is made of a material such as iron (for example, SS400), has a plug head portion 122 and a male screw portion 124, and has a flange between the plug head portion 122 and the male screw portion 124. Part 126 is formed. The gasket 130 is made of a material such as aluminum or copper, and has a disk shape (ring shape) having a through hole formed in the center.

Here, as shown in FIG. 7, the radius of the male screw portion 124 of the inspection port plug 120 (see FIG. 6) is set as the male screw radius R124, and the radius of the inner diameter of the gasket 130 is set as the inner peripheral radius R130N. The outer peripheral radius of the gasket 130 is set as the outer peripheral radius R130G. Note that FIG. 7 shows an example in which the inner peripheral radius R130N is made much larger than the actual one with respect to the male screw radius R124 in order to make the following explanation easier to understand.

When the operator fastens the inspection port plug 120 and the gasket 130 together with the inspection port 144, the inspection port plug 120 and the gasket 130 are fastened together with an impact wrench with a torque converter. The impact wrench with a torque converter can set the tightening torque to a desired torque, but the rotation speed can be set only to 1500 [rpm] or more, for example.

When the operator tightens the inspection port plug 120 and the gasket 130 together with the inspection port 144, first insert the male screw portion 124 of the inspection port plug 120 into the through hole of the gasket 130, and then insert the male screw portion 124 of the inspection port plug 120. The 124 is brought into contact with the inspection port 144. At this time, the gasket 130 moves downward due to gravity and becomes the position of the gasket 130 shown by the solid line in FIG. 7. If the male screw portion 124 of the inspection port plug 120 is screwed in from this state using an impact wrench with a torque converter, the gasket 130 may rotate.

For example, as shown in FIG. 7, when the gasket 130 is rotated from the position of the gasket 130 shown by the solid line to the position of the gasket 130A shown by the dotted line, the outer peripheral edge of the gasket 130 is outside the mounting surface 142. The muscular region 130S may be damaged, and the inner muscular region 130U on the mounting surface 142 may be damaged at the inner peripheral edge of the gasket 130.

In FIG. 7, the distance from the central axis 124J of the male screw portion 124 to the lower end portion of the gasket 130 shown by the solid line is the outer peripheral radius R130G + (inner peripheral radius R130N − male screw radius R124). Therefore, as shown in FIG. 8, the radius of the outer muscular region 130S is the outer peripheral radius R130G + (inner peripheral radius R130N-male screw radius R124), which is larger than the outer peripheral radius R130G which is the outer peripheral radius of the gasket 130. The muscular region 130S is a region that greatly protrudes outward in the radial direction from the outer circumference of the gasket 130.

Since the timing chain is rotating inside the inspection port 144 (see FIG. 6), particulate oil and mist-like oil are present. If the outer muscular region 130S is deeply scratched, oil may seep into the outer muscular region 130S along the scratches due to the capillary phenomenon, and the oil bleeding may be conspicuous. The deeper the scratches on the outer muscular region 130S, the more oil oozes out, and the more conspicuous the oil bleeding is. Further, the more the outer muscular region 130S spreads radially outward from the gasket 130, the more noticeable the oil bleeding is. It is desired to make this oil bleeding less noticeable.

For example, in Patent Document 1, as shown in FIG. 10, an oil pan 203 made of synthetic resin (corresponding to a cover member), a drain plug 220 (corresponding to an inspection port plug), a metal nut 246, and an O-ring of an internal combustion engine are described. A drain plug mounting structure 210 having a ring 212 and a gasket 230 is described.

The metal nut 246 has a cylindrical portion 214 and a hexagonal nut portion 215, and the cylindrical portion 214 is fitted into a through hole 244 provided in the oil pan 203 and provided on the inner side surface of the oil pan 203. The nut portion 215 is fitted to the hexagonal nut fitting portion 205 and fastened to the oil pan 203.

The through hole 244 is sealed in the radial direction by accommodating the O-ring 212 in the O-ring accommodating portion 216, and the gasket 230 is sandwiched between the end face 214b of the cylindrical portion 214 and the drain plug 220 and sealed in the axial direction. There is. This prevents the oil from seeping out from the oil pan 203.

Japanese Unexamined Patent Publication No. 2012-255373

When the drain plug mounting structure described in Patent Document 1 is applied to the inspection port of an internal combustion engine, it is necessary to provide a nut fitting portion and an O-ring accommodating portion on the cover member, or to use a nut and an O-ring separately. The structure becomes complicated.

The present invention was devised in view of these points, and when the inspection port plug detachably attached to the inspection port provided in the internal combustion engine is fastened together with the gasket, the gasket moves around the inspection port. It is an object of the present invention to provide an inspection port oil seal structure capable of making the damage depth or the damage range smaller and making the oil bleeding less noticeable.

In order to solve the above problems, the first invention comprises an inspection port provided in an internal combustion engine, having a circular shape communicating with the outside and the inside of the internal combustion engine, and having a female threaded portion formed on an inner peripheral surface. An inspection port plug having a male screw portion screwed into the female screw portion of the inspection port and a plug head portion provided at the tip of the male screw portion to close the inspection port, and an inspection port plug of the inspection port plug. In an inspection port oil seal structure having an inspection port oil seal structure having a plug head portion and a ring-shaped gasket sandwiched between the plug head portion and the periphery of the inspection port to seal the inspection port, the inspection port is an oil pan of the internal combustion engine. The gasket is provided on a surface along the vertical direction of the internal combustion engine at a position different from the above, and the gasket has an inspection port oil seal structure having a resin coating on the surface.

The second invention is the inspection port oil seal structure according to the first invention, wherein the gasket is between the inner diameter of the through hole through which the male screw portion is inserted and the maximum outer diameter of the male screw portion. It is an inspection port oil seal structure in which the gap between the two is set to 0.1 mm or more and 0.5 mm or less.

The third invention has an inspection port oil seal structure according to the first or second invention. The inspection port is provided on a cover member attached to the internal combustion engine, and the material of the cover member is , Aluminum or an alloy containing aluminum, inspection port oil seal structure.

A fourth invention is a method of attaching an inspection port plug by fastening the gasket and the inspection port plug together to the inspection port of the inspection port oil seal structure according to any one of the first to third inventions. This is an inspection port plug attachment method in which the gasket and the inspection port plug are fastened together with the inspection port with a predetermined torque by an impact wrench with a torque converter.

According to the first invention, it is possible to suppress the occurrence of scratches around the inspection port by making the gasket slippery with respect to the inspection port, and to prevent the scratches from becoming deep by suppressing the rotation of the gasket. it can. As a result, the depth at which the gasket damages the periphery of the inspection port and the extent of the damage can be made smaller, the amount of oil oozing through the scratch can be reduced, and the oil bleeding can be made less noticeable.

According to the second invention, the range in which the gasket is carried can be reduced, and the range in which scratches occur around the inspection port can be reduced. As a result, the range of oil bleeding becomes smaller, and the oil bleeding can be made less noticeable.

According to the third invention, even if the material of the cover member is aluminum, which is a soft metal, or an alloy containing aluminum, the occurrence of scratches around the inspection port is suppressed, and the amount of oil that seeps through the scratches is reduced. It can be reduced and oil bleeding can be made less noticeable.

According to the fourth invention, the gasket and the inspection port plug can be tightened together with a predetermined torque by an impact wrench with a torque converter instead of manually by an operator while suppressing the occurrence of oil bleeding.

It is a front view of the internal combustion engine provided with the cover member in which the inspection port is formed. It is an exploded perspective view of the inspection port oil seal structure. FIG. 5 is a cross-sectional view of an inspection port oil seal structure to which the invention of the present application is applied on an XZ plane including the central axis of the inspection port plug. It is a figure explaining the occurrence of the worm in the IV-IV cross section of FIG. It is a figure which shows the region of the outer squeeze in the inspection port oil seal structure of this application, and the outer squeeze in the conventional inspection port oil seal structure. It is sectional drawing of the conventional inspection port oil seal structure in the XZ plane including the central axis of the inspection port plug. It is a figure explaining the occurrence of the worm in the VII-VII cross section of FIG. FIG. 6 is a diagram showing regions of outer and inner mussels in the VII-VII cross section of FIG. It is a figure which shows the size of the gap between the through hole of a gasket and the male thread part of an inspection port plug, and the judgment result of the quality of a worm. It is sectional drawing of the drain plug mounting structure described in Patent Document 1. FIG.

Hereinafter, an example of the embodiment of the present application will be described with reference to FIGS. 1 to 9. In the figure in which the X-axis, the Y-axis, and the Z-axis are described, the X-axis, the Y-axis, and the Z-axis are orthogonal to each other. The X-axis direction is "front", the direction opposite to the X-axis direction is "rear", the Z-axis direction is "up", and the direction opposite to the Z-axis direction is "down". Further, the Y-axis direction is defined as "right", and the direction opposite to the Y-axis direction is defined as "left".

● [Structure of the inspection port oil seal structure 10 of the present application (FIGS. 1 to 3)]
The configuration of the inspection port oil seal structure 10 of the example of the embodiment for carrying out the invention of the present application will be described with reference to FIGS. 1 to 3. FIG. 1 is a front view of an internal combustion engine 1 provided with a cover member 40 on which an inspection port 44 is formed. FIG. 2 is an exploded perspective view of the inspection port oil seal structure 10.

The internal combustion engine 1 shown in FIG. 1 is an internal combustion engine (reciprocating engine) using a piston. In the internal combustion engine 1, a timing chain 2 for driving a camshaft (not shown) for opening and closing an exhaust valve and an intake valve, and a tensioner 6 for applying tension to the timing chain 2 are arranged in front of the internal combustion engine. .. Although not shown, the tensioner 6 is provided with a rod that can be expanded and contracted in order to press the chain slippers 4 for applying tension to the timing chain 2 against the timing chain 2.

During maintenance or replacement of the timing chain 2, a work tool is used that keeps the length of the rod (not shown) protruding from the tensioner 6 appropriate in order to facilitate the work. Since the operator uses this work tool from the outside of the internal combustion engine 1, a cover member covering the front surface, which is a surface along the vertical direction of the internal combustion engine 1 at a position different from the oil pan (not shown) of the internal combustion engine 1. The 40 is provided with a circular inspection port 44. A bolt-shaped inspection port plug 20 and a gasket 30 are detachably provided in the inspection port 44.

As shown in FIG. 2, the inspection port oil seal structure 10 is composed of an inspection port plug 20, a gasket 30, and an inspection port 44 provided on the cover member 40. The cover member 40 is formed of aluminum which is a soft metal or an alloy containing aluminum, and is an inspection port which is a through hole having a central axis 44J formed in a substantially horizontal direction on a mounting surface 42 along a substantially vertical direction. 44 is provided.

The inspection port plug 20 is made of a material such as iron (for example, SS400), and has a plug head portion 22 and a male screw portion 24. A flange portion 26 is formed on the side of the male screw portion 24 of the plug head portion 22. Since the plug head portion 22 is fitted into the socket on the impact wrench side with a torque converter, it has, for example, a hexagonal columnar shape.

As shown in FIGS. 2 and 3, the gasket 30 is formed of a material such as aluminum or copper (for example, aluminum material A1100P having a thickness of t1.2), and a through hole 32 through which the male screw portion 24 is inserted is formed in the center. It is said to be in the shape of a disk (ring).

In the gasket 30, the male screw portion 24 is screwed into the female screw portion 46 formed on the inner peripheral surface of the inspection port 44, and the gasket 30 is fastened together with the inspection port plug 20 and the inspection port 44. The surface of the gasket 30 that has been tightened together, the surface of the flange portion 26 that abuts the flange surface 26M is the abutting surface 34A, and the surface of the cover member 40 that abuts the mounting surface 42 is the abutting surface 34B. Is.

As shown in FIGS. 2 and 3, each of the contact surface 34A and the contact surface 34B of the gasket 30 is coated with a resin (for example, a silicon coating having a thickness of t0.25). With this resin coating, the coefficient of friction between the flange surface 26M and the contact surface 34A and the coefficient of friction between the mounting surface 42 and the contact surface 34B are each the conventional gasket 130 without resin coating. It is about 1/5 of the coefficient of friction (for example, 0.1) with the surface (contact surfaces 134A, 134B) of (see FIG. 6). As a result, the gasket 30 becomes more slippery than the conventional gasket 130 with respect to the flange surface 26M and the mounting surface 42.

● [Inspection port oil seal structure and occurrence of mussels (Figs. 3 to 9)]
The inspection port oil seal structure 10 of the present application and the conventional inspection port oil seal structure 110 will be described with reference to FIGS. 3 to 9. FIGS. 4, 5 and 9 are diagrams for explaining the inspection port oil seal structure 10 of the present application and the occurrence of mussels. 6 to 8 are diagrams for explaining the conventional inspection port oil seal structure 110 and the occurrence of swelling.

FIG. 3 is a cross-sectional view of an inspection port oil seal structure 10 to which the invention of the present application is applied on an XZ plane including the central axis 24J of the inspection port plug 20. FIG. 6 is a cross-sectional view of a conventional inspection port oil seal structure 110 on an XZ plane including the central axis 124J of the inspection port plug 120. The inspection port oil seal structure 10 is different from the inspection port oil seal structure 110 in that the gasket 130 is a gasket 30, and the other configurations, shapes, and the like are the same except for the reference numerals.

Here, in FIG. 4, the radius of the male screw portion 24 of the inspection port plug 20 (see FIG. 3) is set as the male screw radius R24, the radius of the inner diameter of the gasket 30 is set as the inner peripheral radius R30N, and the gasket 30 is set. The outer peripheral radius is set as the outer peripheral radius R30G. Further, in FIG. 7, the radius of the male screw portion 124 of the inspection port plug 120 is set as the male screw radius R124, the radius of the inner diameter of the gasket 130 is set as the inner peripheral radius R130N, and the outer peripheral radius of the gasket 130 is set as the outer peripheral radius R130G. And set.

In order to make the explanation easier to understand, FIG. 4 shows an example in which the inner peripheral radius R30N is made much larger than the actual one with respect to the male screw radius R24. In FIG. 7, the inner peripheral radius R130N is set with respect to the male screw radius R124. It is shown in an example that is much larger than it actually is.

In FIG. 3, when the operator tightens the inspection port plug 20 and the gasket 30 together with the inspection port 44, first, the male screw portion 24 of the inspection port plug 20 is inserted into the through hole 32 of the gasket 30, and the inspection port plug 20 The male screw portion 24 of the above is brought into contact with the inspection port 44. At this time, the gasket 30 moves downward due to gravity and becomes the position of the gasket 30 shown by the solid line in FIG. In this state, a gap d is formed between the inner diameter of the through hole 32 through which the male screw portion 24 is inserted and the maximum outer diameter of the male screw portion (2 × male screw radius R24 (see FIG. 4)).

Similarly, in FIG. 6, when the inspection port plug 120 and the gasket 130 are fastened together with the inspection port 144, the gasket 130 moves downward due to gravity and becomes the position of the gasket 130 shown by the solid line in FIG. In this state, the male screw radius R124 is the same as the male screw radius R24, and the inner diameter of the through hole 132 is larger than the inner diameter of the through hole 32. The gap dz between the maximum outer diameter of 124 (2 × male screw radius R124 (see FIG. 7)) is larger than the gap d (see FIG. 3) (gap dz> gap d).

[Effect of resin coating on the surface of gasket]
Next, in FIG. 3, when the inspection port plug 20 is rotated around the central axis 24J using an impact wrench with a torque converter, the flange surface 26M rotates around the central axis 24J while maintaining the gap d. It moves along the direction and comes into contact with the contact surface 34A. Since the surface pressure, which is the pressure of the flange surface 26M immediately after contact with the contact surface 34A, is small and the friction coefficient between the flange surface 26M and the contact surface 34A is also small, the flange generated by rotation around the central axis 24J The frictional force between the surface 26M and the contact surface 34A is also reduced. Therefore, the frictional force between the flange surface 26M and the contact surface 34A becomes smaller than the force generated between the flange surface 126M (see FIG. 6) and the contact surface 134A (see FIG. 6) due to the rotational speed. The flange surface 26M rotates while sliding with respect to the contact surface 34A, and the gasket 30 does not rotate with the plug head portion 22 and remains stationary with respect to the mounting surface 42.

In FIG. 3, when the inspection port plug 20 is further screwed along the central axis line 24J times, the surface pressure between the flange surface 26M and the contact surface 34A gradually increases, and the flange surface 26M and the contact surface 34A come together. The frictional force between them also gradually increases. When the frictional force between the flange surface 26M and the contact surface 34A becomes larger than the force generated between the flange surface 26M and the contact surface 34A due to the rotational speed, the gasket 30 has the flange surface 26M on the contact surface 34A. On the other hand, while sliding, it rotates with the plug head portion 22 and rotates while sliding with respect to the mounting surface 42 in an eccentric state (while maintaining the gap d).

In FIG. 6, the friction coefficient between the flange surface 126M and the contact surface 134A is larger than the friction coefficient between the flange surface 26M (see FIG. 3) and the contact surface 34A (see FIG. 3). Even if the surface pressure on the surface 134A is the same as the surface pressure on the contact surface 34A, the frictional force between the flange surface 126M and the contact surface 134A generated by the rotation around the central axis 124J is between the flange surface 26M and the contact surface 34A. It is greater than the frictional force between them. That is, in the gasket 130 of the inspection port oil seal structure 110, the flange surface 126M has the flange surface 126M with respect to the contact surface 134A at a lower rotation speed than the gasket 30 (see FIG. 3) of the inspection port oil seal structure 10 (see FIG. 3). Since it does not slip (the flange surface 126M is fixed to the contact surface 134A) and rotates with the plug head portion 122, it slides against the mounting surface 142 in an eccentric state (while maintaining the gap dz). Rotate.

In the conventional inspection port oil seal structure 110 shown in FIG. 6, since the friction coefficient between the flange surface 126M and the contact surface 134A is large (the flange surface 126M is less likely to slip with respect to the contact surface 134A), the PV value is Since the pressure P (surface pressure) cannot be suppressed, the gasket 130 does not rotate unless the impact wrench with a torque converter has a low rotation speed (V) (for example, 1500 rpm) or less.

On the other hand, in the inspection port oil seal structure 10 of the present application shown in FIG. 3, since the friction coefficient between the flange surface 26M and the contact surface 34A is small (the flange surface 26M is slippery with respect to the contact surface 34A), inspection is performed. Compared to the mouth oil seal structure 110 (see FIG. 6), the pressure P (surface pressure) of the PV value can be suppressed, so that the impact wrench with a torque converter can rotate up to a higher rotation speed (V) (for example, 3000 rpm). , The gasket 30 does not rotate around.

That is, in the inspection port oil seal structure 10, in order to suppress the occurrence of oil bleeding, the operator does not manually tighten the gaskets manually or at a low rotation speed (for example, 1500 rpm) of an impact wrench with a torque converter, but torques them. The gasket and the inspection port plug can be fastened together at a high rotation speed (for example, 3000 rpm) of an impact wrench with a converter. Further, by reducing and suppressing the rotation speed to a high rotation speed (for example, 3000 rpm), the gasket can be fastened together in a short time, so that it is possible to prevent deep scratches. As a result, the depth at which the gasket damages the periphery of the inspection port and the extent of the damage can be made smaller, the amount of oil oozing through the scratch can be reduced, and the oil bleeding can be made less noticeable.

[Effect of reducing the gap between the through hole of the gasket and the male thread of the inspection port plug]
As shown in FIG. 7, when the gasket 130 is rotated from the position of the gasket 130 shown by the solid line to the position of the gasket 130A shown by the dotted line, the gasket 130 is formed on the mounting surface 142 at the outer peripheral edge portion of the gasket 130. It rotates while sliding in the outer muscular region 130S described later, and rotates while sliding in the inner muscular region 130U described later on the mounting surface 142 at the inner peripheral edge portion of the gasket 130.

In FIG. 7, the distance from the central axis 124J of the male screw portion 124 to the lower end portion of the gasket 130 shown by the solid line is the outer peripheral radius R130G + (inner peripheral radius R130N − male screw radius R124). Therefore, as shown in FIG. 8, the radius of the outer muscular region 130S is the outer peripheral radius R130G + (inner peripheral radius R130N-male screw radius R124), which is larger than the outer peripheral radius R130G which is the outer peripheral radius of the gasket 130. The muscular region 130S is a region that greatly protrudes outward in the radial direction from the outer circumference of the gasket 130.

As shown in FIG. 4, when the gasket 30 is rotated from the position of the gasket 30 shown by the solid line to the position of the gasket 30A shown by the dotted line, the gasket 30 is formed on the mounting surface 42 at the outer peripheral edge portion of the gasket 30. It rotates while sliding in the outer muscular region 30S described later, and rotates while sliding in the inner muscular region 30U described later on the mounting surface 42 at the inner peripheral edge portion of the gasket 30.

In FIG. 4, the distance from the central axis 24J of the male screw portion 24 to the lower end portion of the gasket 30 shown by the solid line is the outer peripheral radius R30G + (inner peripheral radius R30N − male screw radius R24). Therefore, as shown in FIG. 5, the radius of the outer muscular region 30S is the outer peripheral radius R30G + (inner peripheral radius R30N-male screw radius R24).

In FIG. 5, the outer meshing region 30S of the gasket 30 (see FIG. 3) in the inspection port oil seal structure 10 (see FIG. 3) of the present application and the gasket 130 (see FIG. 6) in the conventional inspection port oil seal structure 110 (see FIG. 6). 6) shows the outer gasket region 130S.

The radius (solid line) of the outer muscular region 30S is the outer peripheral radius R30G + (inner peripheral radius R30N-male screw radius R24). Further, the radius (dotted line) of the outer muscular region 130S is the outer peripheral radius R130G + (inner peripheral radius R130N-male screw radius R124). Here, the outer peripheral radius R30G and the outer peripheral radius R130G, the male screw radius R24 and the male screw radius R124 are equal, and the inner peripheral radius R130N is larger than the inner peripheral radius R30N. growing. That is, the outer muscular region 130S> the outer muscular region 30S> the outer peripheral radius R30G and the outer peripheral radius R130G, and the muscular region (outer muscular region) decreases. As a result, the area where scratches occur around the inspection port 44 (see FIG. 3) is reduced, and the area of oil bleeding becomes smaller, so that the oil bleeding can be made less noticeable.

As shown in FIGS. 3 and 4, the gasket 30 rotates with the inspection port plug 20 eccentrically around the central axis 24J (while maintaining the gap d). Further, as shown in FIGS. 6 and 7, the gasket 130 rotates in a state where the inspection port plug 120 is eccentric around the central axis 124J (while maintaining the gap dz). When the force applied to the inspection port plugs 20 (see FIG. 3) and 120 (see FIG. 6) from the impact wrench with a torque converter is the same, the area of the outer muscular area 130S is larger than that of the outer muscular area 30S as shown in FIG. Since it is large, the surface pressure in the outer wrench area 130S becomes non-uniform (partially higher) than the surface pressure in the outer wrench area 30S. Therefore, the surface pressure becomes more uniform (not partially increased) in the gap d (the smaller the gap) than in the gap dz, and the gasket 30 is more slippery, and the rotation of the gasket 30 can be suppressed.

[The size of the gap d and the quality judgment result of the worm (Fig. 9)]
FIG. 9 shows the size of the gap d (mm) (0.5 mm, 0.8 mm, 1.2 mm) between the through hole 32 of the gasket 30 and the male screw portion 24 of the inspection port plug 20 in FIG. It is a figure which shows the judgment result of quality.

In FIG. 9, the “range of outer mussels” of the determination item indicates the result of visual inspection of the outer mussels. In the judgment item "range of outer mussels", "◎" in the judgment result indicates the case where it is judged that the range of occurrence of outer mussels is the smallest, and "○" indicates the occurrence of mussels next to "◎". It shows the case where it is judged that the range is small.

The determination item "difficulty in rotating when tightening" indicates the difficulty in rotating the gasket 30 to the inspection port plug 20 when the gasket 30 and the inspection port plug 20 are tightened together to the inspection port 44 (). (See FIG. 3). In the judgment item "difficulty of turning around when tightening", "◎" in the judgment result indicates the case where it is judged that the degree of turning around is the smallest, and "○" and "×" are for "◎". The case where it is determined that the degree of escort is large is shown.

The determination item "insertability of the inspection port plug into the through hole of the gasket" is easy to insert when the operator inserts the male screw portion 24 of the inspection port plug 20 into the through hole 32 of the gasket 30 (insertability). ) Is shown. In the judgment item "insertability of the inspection port plug into the through hole of the gasket", "◎" in the judgment result indicates the case where the operator judges that it is the easiest to insert (insert), and "○" indicates "○". Next to "◎", the case where the operator judges that it is easy to insert is shown.

When the gap d = 0.5 mm, "◎" is the best in both the judgment items "range of outer gasket" and "difficulty in carrying around when tightening", and the judgment item "inspection port plug" The "insertability of the gasket into the through hole" is also "○", and it is easy to insert (insert) the inspection port plug into the through hole of the gasket. That is, the gasket 30 having a gap d = 0.5 mm has a narrow range (a range where scratches can occur) on the mounting surface, and is slippery and does not easily scratch the mounting surface. The lower limit of the gap d is preferably a gap d = 0.1 mm in consideration of the processing accuracy of the gasket and the workability of the operator who inserts the inspection port plug into the through hole.

● [Effect of the present application]
As described above, the gasket 30 becomes slippery with respect to the inspection port 44 to suppress the occurrence of scratches around the inspection port 44, and the gasket 30 suppresses the rotation of the gasket 30 to deepen the scratches. Can be prevented. As a result, the depth at which the gasket 30 damages the periphery of the inspection port 44 and the extent of the damage can be made smaller, the amount of oil that seeps out through the scratches can be reduced, and the oil bleeding can be made less noticeable. it can.

The inspection port oil seal structure of the present invention is not limited to the configuration, structure, etc. described in the present embodiment, and various changes, additions, and deletions can be made without changing the gist of the present invention.

The gasket 30 of the inspection port oil seal structure 10 described in the present embodiment has been described as an example of silicon coating with the surface as a resin coating, but the present invention is not limited to this, and friction against the flange surface 26M and the mounting surface 42 Any resin coating that can reduce the coefficient will do.

1 Internal internal engine 2 Timing chain 4 Chain slipper 6 Tensioner 10 Inspection port oil seal structure 20 Inspection port plug 22 Plug head part 24J Central axis 26 Flange part 26M Flange surface 30, 30A Gasket 30S Outer screw area 30U Inner screw area 32 Through hole 34A , 34B Contact surface 40 Cover member 42 Mounting surface 44 Inspection port 44J Center axis 46 Female thread 110 Inspection port Oil seal structure 120 Inspection port plug 122 Plug head part 124J Center axis 126 Flange part 126M Flange surface 130, 130A Gasket 130S Outside Flange area 130U Inner flange area 132 Through hole 134A, 134B Contact surface 144 Inspection port 144J Center axis 210 Drain plug mounting structure 203 Oil pan 205 Nut fitting part 212 O ring 214 Cylindrical part 214b End face 220 Drain plug 244 Through hole 246 Metal Nut 230 Gasket R24 Male screw radius R30N Inner circumference radius R30G Outer circumference radius R124 Male screw radius R130N Inner circumference radius R130G Outer circumference radius

Claims (4)

An inspection port provided in an internal combustion engine, which has a circular shape that communicates with the outside and the inside of the internal combustion engine and has a female screw portion formed on the inner peripheral surface.
An inspection port plug having a male screw portion screwed into the female screw portion of the inspection port and a plug head portion provided at the tip of the male screw portion to close the inspection port.
In an inspection port oil seal structure having a ring-shaped gasket sandwiched between the plug head portion of the inspection port plug and the periphery of the inspection port to seal the inspection port.
The inspection port is
It is provided on a surface along the vertical direction of the internal combustion engine at a position different from the oil pan of the internal combustion engine.
The gasket is
The surface is resin coated,
Inspection port oil seal structure. The inspection port oil seal structure according to claim 1.
The gasket is
The gap between the inner diameter of the through hole through which the male screw portion is inserted and the maximum outer diameter of the male screw portion is set to 0.1 mm or more and 0.5 mm or less.
Inspection port oil seal structure. The inspection port oil seal structure according to claim 1 or 2.
The inspection port is provided on a cover member attached to the internal combustion engine.
The material of the cover member is aluminum or an alloy containing aluminum.
Inspection port oil seal structure. A method of attaching an inspection port plug by fastening the gasket and the inspection port plug together to the inspection port of the inspection port oil seal structure according to any one of claims 1 to 3.
The gasket and the inspection port plug are fastened together with the inspection port with a predetermined torque by an impact wrench with a torque converter.
Inspection port plug mounting method.

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