JP2008025392A - Attaching structure of oil seal for crankshaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an attaching structure of an oil seal for a crankshaft that allows reducing manufacturing costs by reducing man hours for attaching the seal. <P>SOLUTION: An oil seal 5 for a crankshaft has an annular oil seal retainer 6 having an approximately rectangular cross section that is secured to a housing 4, and an oil seal body 7 held against the inner periphery of the oil seal retainer 6 in an airtight condition, with lip parts 12, 13 on its inner periphery making intimate sliding contact with the crankshaft 2. A plurality of projecting and recessed parts 6c, 6b are formed on the outer peripheral surface 6a of the oil seal retainer 6 along a circumferential direction. Of the plurality of projecting and recessed parts 6c, 6b, the projecting parts 6c are pressed in on the inner peripheral surface 4c of the housing 4, and a seal means 15 for maintaining sealing performance on the outer periphery is provided on the outer peripheral surface 6a. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a crankshaft oil seal mounting structure for sealing a sealing fluid such as engine oil from an end portion of a crankshaft protruding from a crank chamber of an engine so as not to leak to the outside.

Conventionally, as shown in FIG. 6, a crankshaft oil seal 103 is mounted in an annular space formed between an engine housing (cylinder block) 101 and a crankshaft 102. The crankshaft oil seal 103 includes an oil seal retainer 104 fixed to the housing 101, and an oil seal main body 105 held by the oil seal retainer 104 and slidably in close contact with the crankshaft 102. ing. The crankshaft oil seal 103 is attached to the cylinder block 101 by bringing the oil seal retainer 104 into close contact with the end surface of the mounting portion 101a of the cylinder block 101 and fastening them with a plurality of bolts 106 (patent). Reference 1).
JP 2005-233216 A

However, in the mounting structure of the crankshaft oil seal 103 of Patent Document 1, since the oil seal retainer 104 is fixed to the cylinder block 101 by bolting, the cylinder block 101 has a bolt hole, and the oil seal retainer. The through holes need to be formed in 104, and the number of mounting steps increases. For this reason, there was a problem that the manufacturing cost was high.
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a crankshaft oil seal mounting structure that can reduce manufacturing costs by reducing the number of mounting steps.

The crankshaft oil seal mounting structure of the present invention is a crankshaft oil seal mounting structure for sealing an annular space formed between an engine housing and a crankshaft,
The crankshaft oil seal has an annular oil seal retainer that is fixed to the housing and has a substantially rectangular cross section, and an inner peripheral lip portion that is held in an airtight manner at the inner peripheral portion of the oil seal retainer. An oil seal body slidably in close contact with the crankshaft,
A plurality of concave and convex portions are formed along the circumferential direction on the outer peripheral surface of the oil seal retainer, and the convex portions of the plurality of concave and convex portions are press-fitted into the inner peripheral surface of the housing, and the outer peripheral surface includes It is characterized in that sealing means for maintaining the sealing performance on the outer peripheral side is provided.

  According to such a crankshaft oil seal mounting structure, the oil seal retainer is formed into an annular body having a substantially rectangular cross section, and the convex portion of the concave and convex portions formed on the outer peripheral surface thereof is press-fitted into the inner peripheral surface of the housing. Thus, the oil seal for the crankshaft is fixed to the housing, and the sealing performance on the outer peripheral side is ensured by the sealing means provided on the outer peripheral surface of the oil seal retainer. Therefore, by using such an attachment structure, the bolt hole machining to the housing, the through hole machining to the oil seal retainer, and the bolt tightening process, which have been necessary for the installation so far, become unnecessary. For this reason, an installation man-hour can be reduced and, thereby, a manufacturing cost can be reduced. Moreover, a press-fit load can be reduced compared with the case where a metal fitting is carried out to the outer peripheral surface whole periphery because a some convex part fits with a housing partially.

In the structure for mounting the oil seal for crankshaft, the outer peripheral surface of the oil seal retainer is tapered, and concave portions of the plurality of concave and convex portions are formed at the large-diameter end of the outer peripheral surface. It is preferable that the outer peripheral surface of the said large diameter side edge part is comprised as the said convex part.
In this case, the crankshaft oil seal can be smoothly mounted by inserting the taper-shaped outer peripheral surface into the annular space from the smaller diameter side.

In the mounting structure of the crankshaft oil seal, it is preferable that a circumferential section of the convex portion has an arc shape.
In this case, the convex part of the oil seal retainer can be brought into line contact or point contact with the inner peripheral surface of the housing. Thereby, the press-fit load at the time of attachment can further be reduced.

In the crankshaft oil seal mounting structure, it is preferable that the sealing means is a sealant, and the sealant is filled in an annular groove formed in an outer circumferential surface of the oil seal retainer along a circumferential direction.
In this case, the sealability on the outer peripheral side can be easily ensured by the sealant filled in the annular groove formed on the outer peripheral surface of the oil seal retainer.

  According to the mounting structure of the crankshaft oil seal of the present invention, it is not necessary to tighten the bolt when the oil seal retainer of the crankshaft oil seal is fixed to the housing. For this reason, the attachment man-hour accompanying it can be reduced, and, thereby, manufacturing cost can be reduced.

Embodiments of a crankshaft oil seal mounting structure according to the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing a main part of an oil seal mounting structure for a crankshaft according to an embodiment of the present invention, cut along a plane passing through an axial center together with a rear portion of an engine. FIG. 2 is a partially missing view of an unmounted state in which the oil seal for one crankshaft is cut along a plane passing through the shaft center together with a part of the engine. 3 is an enlarged cross-sectional view of the crankshaft oil seal of FIG. 2, FIG. 4 is an arrow view in the IV direction in FIG. 2, and FIG. 5 is an arrow view in the V direction in FIG. .

  In FIG. 1, the crankshaft 2 has a journal portion 2a and a large-diameter flange portion 2b integrally provided at the end of the outside B (left side in FIG. 1) of the journal portion 2a. The flywheel 3 is concentrically attached to the end surface on the outer side B of the flange portion 2b. The cylinder block 4 as a housing has a bearing portion 4a for rotatably supporting the journal portion 2a, and a mounting portion 4b formed so as to project around the bearing portion 4a in a substantially arch shape. .

  The crankshaft oil seal 5 is for sealing the sealing fluid flowing out from the space between the bearing portion 4a of the cylinder block 4 and the journal portion 2a of the crankshaft 2 to the outside B, as shown in FIG. The metal oil seal retainer 6 is an annular body having a substantially rectangular cross section, and the oil seal main body 7 is airtightly held on the inner periphery of the oil seal retainer 6.

  As shown in FIG. 3, the oil seal retainer 6 has an outer end on the engine side A (right side in FIG. 1) having a smaller diameter than the inner peripheral surface 4c of the mounting portion 4b and an outer end B end having a larger diameter. Thus, the outer peripheral surface 6a is tapered. Then, as shown in FIG. 4, a plurality of recesses 6b are formed at predetermined intervals along the circumferential direction at the outer side B end of the outer peripheral surface 6a, whereby uneven portions are provided alternately in the circumferential direction. become. And the outer peripheral surface of the outer side B edge part between this recessed part 6b is comprised as the convex part 6c, and this convex part 6c will carry out metal fitting with the inner peripheral surface 4c of the attaching part 4b of the cylinder block 4. FIG. . Here, the circumferential cross section of the convex portion 6c has an arc shape, and the apex of the convex portion 6c is in point contact with the inner peripheral surface 4c of the mounting portion 4b. An annular groove 6d is formed along the circumferential direction on the engine side A of the outer peripheral surface 6a, and the annular groove 6d is filled with a sealant (for example, a liquid gasket) 15 as a sealing means. Further, as shown in FIG. 5, a plurality (two in this case) of pin holes 6 f are formed on the surface of the engine side A, and these pin holes 6 f are formed on the surfaces of the cylinder block 4 facing each other. Positioning is performed by inserting a positioning pin (not shown) into the pin hole 4d (see FIG. 1).

The oil seal main body 7 is held in an airtight manner on the inner peripheral portion of the oil seal retainer 6. For example, the oil seal main body 7 is fixed to the cored bar 8 having an L-shaped annular cored bar 8 as shown in FIG. A sealing member 9 and an annular spring ring 10 are provided.
The cored bar 8 is a metal annular member, and includes a cylindrical portion 8a and an annular plate portion 8b bent inward in the radial direction from the outer side B end portion of the cylindrical portion 8a.

The seal member 9 is made of an elastic member such as synthetic rubber, and is fixed to the cored bar 8 by adhesion or baking by vulcanization. The seal member 9 has a main body portion 11 and lip portions (main lip 12 and dust lip 13).
The body portion 11 is provided on the outer peripheral side of the cylindrical portion 8a of the core metal 8 and fixed to the inner peripheral surface 6e of the oil seal retainer 6, and the outer side B and the inner peripheral side of the annular plate portion 8b. It is comprised with the intermediate part 11b which covers an area | region.

The main lip 12 extends from the inner peripheral side of the intermediate part 11b of the main body part 11 to the crankshaft 2 side and to the engine side A, and a peripheral groove 12a is formed on the outer peripheral surface thereof. A spring ring 10 called a so-called garter spring is attached to the circumferential groove 12a, and the main lip 12 is fastened radially inward. The main lip 12 is brought into contact with the flange portion 2b of the crankshaft 2 with a margin to prevent the sealing fluid on the engine side A from leaking to the outer side B. Here, the cross-sectional shape of the main lip 12 is narrowed toward the inside in the radial direction (the axial width dimension is small) and is substantially V-shaped, and the minimum diameter (top) is the lip tip 12b. Yes. On the inner peripheral surface of the main lip 12, a plurality of protrusions 14 are provided on the surface on the outer side B from the lip tip portion 12 b to return the sealing fluid to be leaked by the rotation of the crankshaft 2 to the engine side A. Is formed.
The dust lip 13 extends from the inner peripheral side of the intermediate portion 11b of the main body 11 to the crankshaft 2 side and to the outer side B, and makes contact with the flange portion 2b of the crankshaft 2 with a tightening margin, or the tightening margin is zero. Intrusion of foreign matter from the outside B into the engine A is prevented as a small clearance.

  The crankshaft oil seal 5 is attached by first filling the annular groove 6d of the oil seal retainer 6 with a sealant 15 as a sealing means. Then, the position of the pin hole 6f of the oil seal retainer 6 is aligned with a positioning pin (not shown) inserted into the pin hole 4d of the cylinder block 4, and the oil seal retainer 6 is moved from the small diameter side surface shown in FIG. Insert on side A. At this time, the outer peripheral surface 6a of the oil seal retainer 6 is tapered, and the surface on the engine side A is smaller in diameter than the inner peripheral surface 4c of the mounting portion 4b, so that it can be inserted smoothly. Furthermore, the oil seal retainer 6 is fixed to the mounting portion 4b of the cylinder block 4 by press-fitting the convex portion 6c of the oil seal retainer 6 into the inner peripheral surface 4c of the mounting portion 4b. The lower part of the oil seal retainer 6 is fitted into an oil pan (not shown) as a housing. Finally, the oil seal body 7 is fitted to the inner peripheral surface 6 e of the oil seal retainer 6. As a result, the airtightness between the oil seal body 7 and the oil seal retainer 6 is maintained, and the inner lip portion (main lip 12 and dust lip 13) of the oil seal body 7 is the flange portion of the crankshaft 2. 2b is slidably brought into close contact with the inner periphery to maintain the sealing performance.

According to the crankshaft oil seal mounting structure 1 as described above, the oil seal retainer 6 is formed into an annular body having a substantially rectangular cross section, and the convex portion 6c among the concave and convex portions 6b and 6c formed on the outer peripheral surface 6a is provided. The crankshaft oil seal 5 is fixed to the cylinder block 4 by being press-fitted into the inner peripheral surface 4c of the housing (cylinder block) 4, and an annular groove 6d formed in the outer peripheral surface 6a of the oil seal retainer 6 along the circumferential direction. Since the sealing means (sealant) 15 is filled with the sealing means on the outer peripheral side can be easily secured. Therefore, with the mounting structure 1 as described above, the bolt hole machining to the cylinder block 4, the through hole machining to the oil seal retainer 6, and the bolt tightening process which have been required up to now are unnecessary. For this reason, an installation man-hour can be reduced and, thereby, a manufacturing cost can be reduced.
In the above embodiment, the outer peripheral surface 6a of the oil seal retainer 6 is tapered, and the concave portion 6b of the plurality of concave and convex portions is formed at the outer side B (large diameter side) end of the outer peripheral surface 6a. The outer peripheral surface of the outer side B end between the recesses 6b is configured as a projection 6c. As a result, the crankshaft oil seal 5 is smoothly attached by being inserted into the annular space from the small diameter side of the tapered outer peripheral surface 6a. Furthermore, since the circumferential section of the convex portion 6 c is arcuate, the convex portion 6 c can be brought into point contact with the inner peripheral surface 4 c of the cylinder block 4. Thereby, compared with the case where the outer peripheral surface 6a whole metal fitting is carried out, a press-fit load can be reduced.

The crankshaft oil seal mounting structure 1 according to the present invention is not limited to the above-described embodiment, and within the scope of the present invention, the dimensions, materials, shapes, relative arrangements, and the like of the component parts are appropriately changed. Can do.
The number of the recesses 6b, the protrusions 6c, and the pin holes 6f of the oil seal retainer 6 is not limited to the above embodiment, and can be changed as appropriate. In the above embodiment, the outer peripheral surface 6a of the oil seal retainer 6 is tapered, and the outer side B end of the outer peripheral surface 6a is formed with the concave portions 6b among the plurality of concave and convex portions, and the outer side between the concave portions 6b. Although the outer peripheral surface of B edge part is comprised as the convex part 6c, it is not limited to this. If a plurality of concavo-convex portions are formed and the convex portions are press-fitted, the outer peripheral surface 6a of the oil seal retainer 6 does not need to be tapered, and the concavo-convex portions are formed on the outer side B (large size) of the outer peripheral surface 6a. (Diameter side) It does not need to be provided at the end. Moreover, although the circumferential cross section of the convex part 6c is made into circular arc shape, it is not restricted to circular arc shape, and the recessed part 6b does not need to be formed at equal intervals. Furthermore, as the housing 4, a housing having a step such as a split housing can be used.
The sealing means is not limited to the sealant 15, and for example, an O-ring or the like can be used.
The oil seal main body 7 is not limited to the one shown in the above embodiment, and the oil seal retainer 6 is airtightly held on the inner peripheral portion of the oil seal retainer 6, and the inner peripheral lip portions 12 and 13 slide on the crankshaft 2. Any device that can move freely can be used without limitation. Further, the oil seal main body 7 does not have to be formed separately from the oil seal retainer 6 as in the above embodiment, and may be formed integrally with the oil seal retainer 6.

It is sectional drawing which cut | disconnects and shows the principal part of the attachment structure of the crankshaft oil seal which concerns on one embodiment of this invention with the plane which passes along an axial center with the rear part of an engine. FIG. 2 is a partially missing view of the crankshaft oil seal of FIG. 1 cut along a plane passing through the shaft center together with a part of the engine. FIG. 3 is an enlarged cross-sectional view of the crankshaft oil seal of FIG. 2. It is an arrow view of the IV direction in FIG. FIG. 3 is an arrow view in the V direction in FIG. 2. It is sectional drawing which shows the attachment structure of the conventional oil seal for crankshafts cut | disconnected by the plane which passes along the axial center.

Explanation of symbols

1 Crankshaft oil seal mounting structure 2 Crankshaft 4 Cylinder block (housing)
5 Crankshaft oil seal 6 Oil seal retainer 6c Convex 7 Oil seal body 15 Sealant (sealing means)
A Engine side B External side

Claims (4)

A crankshaft oil seal mounting structure for sealing an annular space formed between an engine housing and a crankshaft,
The crankshaft oil seal has an annular oil seal retainer that is fixed to the housing and has a substantially rectangular cross section, and an inner peripheral lip portion that is held in an airtight manner at the inner peripheral portion of the oil seal retainer. An oil seal body slidably in close contact with the crankshaft,
A plurality of concave and convex portions are formed along the circumferential direction on the outer peripheral surface of the oil seal retainer, and the convex portions of the plurality of concave and convex portions are press-fitted into the inner peripheral surface of the housing, and the outer peripheral surface includes An oil seal mounting structure for a crankshaft, characterized in that a sealing means for maintaining the sealing performance on the outer peripheral side is provided.   An outer peripheral surface of the oil seal retainer is tapered, and a concave portion of the plurality of concave and convex portions is formed at a large diameter side end portion of the outer peripheral surface, and an outer peripheral surface of the large diameter side end portion between the concave portions is The structure for attaching an oil seal for a crankshaft according to claim 1, wherein the structure is configured as the convex portion.   The structure for attaching an oil seal for a crankshaft according to claim 1 or 2, wherein a circumferential cross section of the convex portion has an arc shape.   The crankshaft according to any one of claims 1 to 3, wherein the sealing means is a sealant, and the sealant is filled in an annular groove formed in an outer peripheral surface of the oil seal retainer along a circumferential direction. Oil seal mounting structure.

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