JP4709068B2 - Head cover seal structure - Google Patents

Description

  The present invention relates to a seal structure of a head cover in which a seal member is interposed between a mounting hole of a synthetic resin head cover of an internal combustion engine and a mounting member such as a fuel injection valve or a spark plug.

As described in Patent Documents 1 to 3, the engine head cover (also referred to as a rocker cover) includes a plurality of tubular mounting members such as a fuel injection valve in a diesel engine and a spark plug in a gasoline engine. An attachment hole is formed through, and a gap between the peripheral wall portion of the attachment hole and the attachment member is liquid-tightly sealed with a seal member such as an oil seal.
Japanese Utility Model Publication No. 4-117293 Japanese Utility Model Publication No. 6-34153 JP 2004-052705 A

  When the head cover is made of synthetic resin, it can be reduced in weight and cost compared to a metal head cover such as an aluminum alloy, but it is difficult to ensure the assembly accuracy and assembly rigidity of the seal member. There is a risk that the seal member may be displaced or fall off due to vibrations and the like. As a countermeasure, if the seal member is securely fixed to the head cover by vibration welding or the like, the seal member cannot be removed from the head cover after being fixed once. For example, even when the seal member is damaged during assembly, the seal member There is a problem that it is not possible to exchange a single item. In addition, it is conceivable to firmly fix the seal member to the head cover using an appropriate clasp or bracket. However, in this case, the number of parts increases, the weight increases, the size increases, and the assembly work is complicated. There is a problem of becoming.

The present invention has been made in view of such problems, and a head cover in which an annular seal member is interposed between a hole peripheral wall portion of a mounting hole of a synthetic resin head cover and a mounting member fitted thereto. In the seal structure of
When the insertion direction of the seal member with respect to the hole peripheral wall portion is a downward direction,
The hole peripheral wall portion has a cylindrical portion and a flange portion projecting radially inward from the lower end of the cylindrical portion,
The seal member is folded back from the upper end of the central leg portion to the outer peripheral side along the insertion direction of the seal member with respect to the hole peripheral wall portion, and a predetermined gap is provided between the center leg portion. An outer leg disposed with a gap therebetween,
The outer leg is provided with a small-diameter portion having a smaller radial dimension than the protruding portion and the large-diameter portion between the protruding portion at the lower tip and the large-diameter portion on the upper side,
By inserting the seal member into the hole peripheral wall portion in the insertion direction, the protrusion gets over the flange portion, the large-diameter portion is in close contact with the cylindrical portion, and the small-diameter portion is in close contact with the flange portion. member is characterized Rukoto assembled detachably to the hole peripheral wall portion.

  According to the present invention as described above, by inserting the seal member into the hole peripheral wall portion, the inner periphery of the hole peripheral wall portion where the irregularities are formed and the outer periphery of the seal member are in close contact, and the seal member is pivoted to the hole peripheral wall portion. It can be firmly assembled without wobbling in the direction or radial direction. For this reason, inadvertent dropout and position shift due to vibration from the engine or the like do not occur. In addition, since the seal member is not fixed to the head cover side by welding or the like as in the above-described conventional example, the seal member can be removed from the head cover after assembly, that is, replacement with a single seal member is possible. Furthermore, since there are no parts such as clasps or brackets for attaching the seal member to the hole peripheral wall portion, the number of parts is small, the weight and size can be reduced, and the assembly work is easy.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. 3 and 4 show a single head cover 1 of an in-line four-cylinder engine to which a seal structure according to an embodiment of the present invention is applied. The head cover 1 is integrally molded with a lightweight and inexpensive synthetic resin material, and is provided with a plurality of fixing bolts (not shown) that are inserted and fitted into a plurality of bolt boss portions 2 formed on the peripheral edge thereof. The head gasket (not shown) is sandwiched between the upper part of the cylinder head (not shown) and fixed together. A plurality of attachment holes 3A are formed in the head cover 1 along the cylinder row direction, and a cylindrical attachment member 4 is attached to the hole peripheral wall 3 of the attachment hole 3A. The attachment member 4 is, for example, a high-pressure common rail fuel injection valve in a diesel engine, and a spark plug in a gasoline engine. An oil seal 10 (see FIGS. 1 and 2) as a seal member is interposed between the holes 3 and 4 so as to fill the gap between the hole peripheral wall 3 and the mounting member 4 and seal this portion. The oil seal 10 separates or seals the inside of the head cover 1 in an oil atmosphere in which engine oil scatters.

  1 and 2 are cross-sectional views of the vicinity of the oil seal 10 and the mounting hole 3A of the head cover 1. In the present embodiment, by inserting the oil seal 10 into the hole peripheral wall portion 3 along the insertion direction F, the inside of the hole peripheral wall portion 3 that is in close contact with each other so that the oil seal 10 is firmly assembled to the hole peripheral wall portion 3. Concavities and convexities that are fitted to each other are formed on the circumference (surface) and the outer circumference (surface) of the oil seal 10.

  The insertion direction F is along the axial direction of the mounting member 4, the hole peripheral wall 3 and the oil seal 10. In this specification, “up and down” basically refers to the downward insertion direction F in FIG. The “down” direction is used, and the direction along the insertion direction F is used as the “up and down” direction.

  Most of the head cover 1 is formed by a general wall portion 5 having a predetermined thickness. Each hole peripheral wall portion 3 of the head cover 1 is constituted by a substantially cylindrical tube portion 6 extending downward from the general wall portion 5 and a flange portion 7 projecting radially inward from the lower end of the tube portion 6. ing.

  The oil seal 10 is integrally molded with an elastic material such as rubber, with a metal core 11 and a spring 12 enclosed therein. The oil seal 10 includes a central leg 13 having a substantially cylindrical shape along the insertion direction (axial direction) F, an outer leg 14 that is in close contact with the hole peripheral wall 3, and an inner leg that is in close contact with the outer periphery of the mounting member 4. 15, and these leg portions 13 to 15 have a shape connected in a substantially S-shaped cross section. The outer leg portion 14 is arranged on the outer side in the radial direction of the central leg portion 13, that is, on the outer peripheral side via a predetermined gap 16, and is connected to the central leg portion 13 on the upper side. It is buried over almost the entire length of F. The inner leg portion 15 is disposed on the radially inner side of the central leg portion 13, that is, on the inner peripheral side via a predetermined gap 17, and is connected to the central leg portion 13 on the lower side, and the upper end portion thereof is embedded inside. The spring 12 is strongly brought into close contact with the outer periphery of the mounting member 4.

  The outer leg portion 14 has a cylindrical small-diameter portion 19 and a large-diameter portion 18 projecting radially outward from the upper end of the small-diameter portion 19, that is, having a larger radial dimension than the small-diameter portion 19. , And a protrusion 20 protruding outward in the radial direction from the lower end of the small diameter portion 19. In other words, a groove-shaped small-diameter portion 19 into which the flange portion 7 is fitted is formed between the large-diameter portion 18 and the protrusion 20.

  When the oil seal 10 is assembled, if the oil seal 10 is inserted and inserted into the hole peripheral wall portion 3 along the insertion direction F, the protrusion 20 gets over the flange portion 7 and the assembly as shown in FIG. The cylindrical portion 6 is tightly fitted and fitted to the large diameter portion 18, the flange portion 7 is tightly fitted and fitted to the small diameter portion 19, and the corner portion on the outer peripheral side of the lower end of the flange portion 7 protrudes. It closely adheres to the part 20. That is, the outer periphery of the outer leg portion 14 on which the irregularities are formed and the inner periphery of the hole peripheral wall portion 3, including the stepped surface between the large diameter portion 18 and the small diameter portion 19, and the inner periphery of the hole peripheral wall portion 3 are substantially in tight contact with each other. The seal 10 is firmly assembled to the hole peripheral wall 3 without wobbling in the insertion direction F or the radial direction, and does not drop off or be displaced due to vibration from the engine or the like.

  The outer peripheral lower surface side corner of the projecting portion 20 abutted against each other and the inner periphery of the flange portion 7 so that the projecting portion 20 can successfully get over the flange portion 7 having a smaller diameter at the time of insertion / insertion. Tapered surfaces 20B and 8 that are inclined (or curved) are formed at the upper surface side corner portion, respectively.

  Further, since the oil seal 10 is fitted and assembled to the head cover 1 in this way, it can be removed from the head cover 1 for reasons of replacement after the assembly, and in consideration of workability at the time of removal, That is, the upper surface of the protrusion 20 is also formed with a tapered surface 20A that is inclined (or curved) so as to reduce the load when the oil seal 10 is pulled out from the hole peripheral wall 3. That is, the protrusion 20 has a shape that protrudes in a substantially V shape in the radial direction by the two tapered surfaces 20A and 20B.

Further, the large-diameter portion 18 is set to have a sufficiently larger radial dimension than the cylindrical portion 6 in order to ensure the desired adhesion force, that is, assembly rigidity. Therefore, the large-diameter portion 18 is greatly elastically deformed when the oil seal 10 is assembled. In order to suppress / prevent an excessive increase in insertion force and an irregular deformation mode due to the elastic deformation, A concave groove 23 is formed on the upper surface of the portion 18 to allow and absorb elastic deformation of the large diameter portion 18. In consideration of insertion workability, tapered surfaces 21 and 22 that are inclined or curved are formed at the inner peripheral upper surface side corner portion of the cylindrical portion 6 and the outer peripheral lower surface side corner portion of the large diameter portion 18, respectively. .

  Note that the tapered surface described above is set to a predetermined inclination angle and curvature in consideration of the load required during assembly / removal, unlike a simple chamfered portion such as a general chamfered portion. It is what is done. For example, the tapered surface 20B on the lower side of the protrusion 20 is set to a gentle and long inclination angle of about 30 degrees with respect to the axial direction F.

  Further, on the outer periphery of the outer leg portion 14 that is in close contact with the inner periphery of the hole peripheral wall portion 3, a large-diameter portion 18, a small-diameter portion 19, and a protrusion 20 are mainly used to reduce the load when the oil seal 10 is assembled and removed. An appropriate surface treatment agent such as dry wax is coated on the entire surface including

  Furthermore, since the core member 11 extends in the outer leg 14 over almost the entire length of the close contact portion with the hole peripheral wall 3 in the axial direction F, a sufficiently high pressure contact force and consequently assembly rigidity should be ensured. Can do. In addition, since the gap 16 is secured between the lower portion of the outer leg portion 14 where the small-diameter portion 19 and the protrusion 20 exist and the central leg portion 13, the influence of the pressure contact force is a seal portion of the inner leg portion 15. It is possible to reduce or avoid adversely affecting the projection, and the protrusion 20 can be appropriately bent inward during assembly and removal.

  Next, the dust cover 30 assembled to the oil seal 10 will be described. The dust cover 30 prevents dust and the like from entering the seal portion between the inner periphery of the inner leg portion 15 of the oil seal 10 and the outer periphery of the mounting member 4, and is arranged so as to cover the upper portion of the seal portion. Established. In the present embodiment, the dust cover 30 is firmly assembled to the oil seal 10 by inserting and inserting the dust cover 30 into the oil seal 10 along the insertion direction F. Specifically, the dust cover 30 includes an annular seal portion 31 that contacts the outer periphery of the mounting member 4 and a metal portion 32 that is fitted and assembled to the upper inner periphery of the central leg portion 13 of the oil seal 10. ing. The metal part 32 is bent by a metal material, and has an annular part 33 to which the outer periphery of the seal part 31 is connected, and a cylindrical part 34 that forms a cylinder disposed on the outermost peripheral side. is doing. A fitting groove portion 35 into which the cylindrical portion 34 is fitted is recessed on the upper inner peripheral side of the central leg portion 13, and substantially V-shaped radially inwardly above the fitting groove portion 35. A protrusion 36 is formed in a protruding shape (triangular cross section).

  With the above configuration, when the dust cover 30 is assembled, when the dust cover 30 is inserted into the oil seal 10 in the insertion direction F, the outermost cylindrical portion 34 of the dust cover 30 gets over the protrusion 36 and fits. The dust cover 30 is fitted into the groove 35 in a close contact state, and the dust cover 30 is firmly assembled to the oil seal 10 so that it does not fall off or be displaced due to vibration from the engine or the like. In addition, with such an assembly structure, the dust cover 30 can be removed from the oil seal 10 after assembly unlike the fixing by vibration welding or the like, and only the dust cover 30 can be replaced, which is cost effective. It is advantageous.

  In particular, in this embodiment, there is no gap (16) between the upper portion of the central leg portion 13 into which the cylindrical portion 34 on the outer peripheral side of the dust cover 30 is fitted and the outer leg portion 14 in which the core material 11 is embedded. It has a thick and solid shape, and the core material 11 is set so as to extend over the entire length of the cylindrical portion 34 in the axial direction F, so that sufficient compression pressure and assembly rigidity can be obtained. Can be secured. Further, since the inner peripheral surface of the protrusion 36 is constituted by a pair of inclined surfaces projecting in a substantially V shape in the radial direction like the above-described protrusion 20, when assembling and removing the dust cover 30, The cylindrical portion 34 can smoothly get over the protruding portion 36, and the workability is improved.

  As described above, the present invention has been described based on the specific embodiments. However, the present invention is not limited to the above-described embodiments, and includes various modifications and changes without departing from the spirit of the present invention. . For example, in the above-described embodiment, the protrusion 20 of the oil seal 10 is provided over the entire circumference, but in consideration of a balance between an appropriate drop-off prevention force and a load necessary for assembly and removal, the protrusion is arranged in the circumferential direction. The contact area may be adjusted intermittently.

1 is a cross-sectional view in an assembled state showing the vicinity of an oil seal to which a seal structure according to an embodiment of the present invention is applied and an attachment hole of a head cover. Sectional drawing in the state before an assembly | attachment which shows the vicinity of the oil seal of FIG. 1, and the attachment hole of a head cover. The top view which shows the head cover with which a present Example is applied alone. Sectional drawing which follows the AA line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Head cover 3A ... Mounting hole 3 ... Hole surrounding wall part 4 ... Mounting member 6 ... Cylindrical part 7 ... Flange part 10 ... Oil seal (seal member)
DESCRIPTION OF SYMBOLS 11 ... Core material 18 ... Large diameter part 19 ... Small diameter part 20 ... Projection part 30 ... Dust cover 34 ... Cylindrical part 35 ... Fitting groove part

Claims (4)

In the seal structure of the head cover in which an annular seal member is interposed between the hole peripheral wall portion of the mounting hole of the synthetic resin head cover and the mounting member fitted thereto,
When the insertion direction of the seal member with respect to the hole peripheral wall portion is a downward direction,
The hole peripheral wall portion has a cylindrical portion and a flange portion projecting radially inward from the lower end of the cylindrical portion,
The seal member is folded back from the upper end of the central leg portion to the outer peripheral side along the insertion direction of the seal member with respect to the hole peripheral wall portion, and a predetermined gap is provided between the center leg portion. An outer leg disposed with a gap therebetween,
The outer leg is provided with a small-diameter portion having a smaller radial dimension than the protruding portion and the large-diameter portion between the protruding portion at the lower tip and the large-diameter portion on the upper side,
By inserting the seal member into the hole peripheral wall portion in the insertion direction, the protrusion gets over the flange portion, the large diameter portion is in close contact with the cylindrical portion, and the small diameter portion is in close contact with the flange portion, so that the seal seal structure of the head cover which member is characterized by a Turkey assembled detachably to the hole peripheral wall portion.   The reinforcing member is embedded in the inside of the seal member, and the core member extends over the entire length of the close contact portion between the seal member and the hole peripheral wall portion in the axial direction. The seal structure of the described head cover. And the outer bottom surface side corner portion of the upper Symbol projections, and the inner upper surface corner portion of the flange portion, at least one of, wherein the tapered surface which is inclined or curved is formed according to claim 1 or 2 2. The head cover seal structure described in 1.   By inserting a dust cover that covers the upper part of the seal portion between the seal member and the mounting member into the seal member, a metal cylindrical portion is provided on the outer periphery of the dust cover so that the dust cover is firmly assembled to the seal member. The head cover seal structure according to claim 1, wherein a fitting groove portion into which the cylindrical portion is fitted is formed on an inner periphery of the seal member.

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