JP2017089814A - Double-tank type oil pan of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve cost reduction and durability, in a double-tank type oil pan in which a seal member is attached to a flange of an inner tank.SOLUTION: An elastomer-made seal member 6 is attached to a flange 5 of an inner tank 2 by an insert-molding method. A large number of communication holes 7, 8 are formed at the flange 5 at intervals. The seal member 6 has: upper/lower layers 9, 10 for sandwiching the flange 5 from up-and-down directions; joints 11, 12 for connecting the upper/lower layers 9, 10 via the communication holes 7, 8; a continuous part 13 for connecting the upper/lower layers 9, 10 at the outside of the flange 5; and a lip 14 which outwardly overhangs. By the existence of the joints 11, 12, the seal part 6 is held so as not to be releasable. The communication holes 7, 8 are paired into an upper-spread type and a lower-spread type, and a pair of the holes are aligned in a peripheral direction. Therefore, a stress concentration with respect to either of external forces in the up-and-down directions can be suppressed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a two-tank oil pan in an internal combustion engine for automobiles and the like.

  2. Description of the Related Art In an internal combustion engine for automobiles, an oil pan is configured in a two-tank type with an outer tank and an inner tank in order to promote the temperature rise of oil during warm-up operation or the like. In this two tank type oil pan, there is a gap between the outer tank and the inner tank, but in order to prevent oil from flowing into the gap from above, a sealing material is provided at the upper end of the inner tank. (Oil often flows into the gap in part of the periphery of the oil pan, so normally the sealing material does not need to be provided on the entire circumference, and is provided only at the location where the oil flows).

  The sealing material is attached to a flange provided at the upper end of the inner tank. As an example, Patent Document 1 discloses a structure in which a rubber lip is integrally formed on a resin plate that overlaps the flange of the inner tank (separator) from above. As shown in the figure, insert holes in the upper and lower back openings at appropriate intervals in the plate, while the flange of the inner tub is provided in advance with a convex part that fits the insertion hole, and the protrusion is formed after the plate is overlaid on the flange. It is disclosed that the plate is fixed to the flange by heat caulking.

Japanese Patent Application Laid-Open No. 2015-10507

  In Patent Document 1, the plate is made of a material that does not have elasticity such as rubber, and the rubber lip is injection-molded on the plate as a soft seal portion while the plate is firmly fixed to the inner tank by heat caulking. As a result, sealing performance is secured.

  However, Patent Document 1 has a problem that it takes time to attach the rubber lip to the plate by injection molding (insert molding) and a problem that it takes time to heat the caulking process. As a result, it cannot be denied that the cost increases. In addition, the rubber lip is molded and fixed to the plate by vulcanization in a mold holding the plate. However, when the rubber lip deteriorates, there is a concern that the joint may peel off and drop off due to vibration. .

  The present invention has been made to improve the current situation.

  The oil pan of the present invention comprises an outer tub and a resin inner tub, and an outward flange is integrally formed at the upper edge of the inner tub, and the flange is formed on the inner surface of the outer tub. This is a basic configuration in which an abutting elastomer sealing member is attached by integral molding.

And, in the flange of the inner tank, a large number of communicating holes opened up and down are formed in the circumferential direction, and the communicating holes are of an upwardly expanding type in which at least the upper part is expanded upward, and at least the lower part is downwardly facing downward. While there is an expanded lower diameter type, the upper spread type and the lower spread type are mixedly arranged in the circumferential direction,
The seal member includes an upper layer that overlaps the upper surface of the flange, a lower layer that overlaps the lower surface of the flange, and a joint that enters each communication hole of the flange and connects the upper layer and the lower layer.

  In the present invention, the communication hole may extend upward or downward over the entire height, or may have a form in which only the upper part or only the lower part extends and has a straight part. As an aspect in which the upper spreading type communication holes and the lower spreading type communication holes are mixed in the circumferential direction, the state in which the upper spreading type and the lower spreading type are alternately arranged is suitable for orthodox. It also includes a state in which a plurality of spread types and bottom spread types are arranged.

  Further, as a specific form of the upward spread and the downward spread, a trapezoidal shape is possible, but for the purpose of preventing stress concentration on the seal member, it is a trumpet shape in which the spread surface is an arc surface. Is preferred. Furthermore, although the upper layer and lower layer which comprise a sealing member may be connected only by the joint, it is preferable that it is connected integrally also in the connection part of the outer side of a flange. That is, it is preferable that the upper layer and the lower layer hold the flange.

  In the present invention, since the sealing material is entirely formed of an elastomer, the structure can be simplified and the cost can be reduced as compared with a material including a plate and a rubber lip as in Patent Document 1. In addition, there is no problem such as aging or separation due to vibration, and it is excellent in reliability.

  Since the elastomer is soft, it can be elastically deformed to contact the outer tub and ensure sealing performance. However, when it is soft, external force is applied for some reason in fixing by heat caulking as in Patent Document 1. And there exists a possibility that a sealing material may remove | deviate from a flange by a deformation | transformation.

  In this regard, in the present invention, since the sealing material has an upper layer and a lower layer and both are connected by a joint, even if an upward external force acts on the upper layer, it does not come off from the flange. In addition, the sealing material is attached to the flange by an integral molding method such as an insert molding method or a two-color molding method, and the molding of the sealing material and the fixing to the flange are performed at the same time. Can also contribute to cost reduction.

  Now, the inner tank is manufactured by injection molding, and the communication hole of the flange is formed by a boss provided in the mold. In this case, if the boss part is a straight cylindrical shape, the upper and lower edges of the communication hole in the flange become a right-angled edge, and the joint base is also squared at a corresponding angle. When applied, stress concentrates at the base of the joint and breaks easily.

  About this point, a boss is provided opposite to two molds, a fillet is provided at the base of both bosses, and the boss part is shaped like a hem so that the upper and lower openings of the communication hole are in a trumpet shape. However, in this case, since the bosses facing each other may be misaligned, the molding accuracy may be deteriorated. Further, since the boss portions must be provided in the two molds by the number of communication holes, the processing of the boss portions is also troublesome.

  On the other hand, when the upward spreading type and the downward spreading type are mixed as in the invention of the present application, the root is widened in both cases, whether an upward external force or a downward external force is applied to the seal member. Since the concentration of stress is suppressed by the joint, breakage can be firmly prevented. Therefore, high reliability can be ensured.

  Also, in terms of the structure of the mold for molding, the boss part for forming the upper spreading type communication hole is provided in one mold, and the boss part for forming the lower spreading type communication hole is Since it is provided in the other mold, there is no problem of reduction in molding accuracy due to misalignment. Moreover, since the boss | hub part needs the same number as a communicating hole, the effort of a process can also be suppressed.

(A) is a rough top view of embodiment, (B) is BB sectional drawing of (A), (C) is sectional drawing which shows the formation process of a sealing member. It is II-II sectional view taken on the line of FIG. FIG. 3A is a view showing a molding process of a flange, wherein FIG. 1A shows the molding of the point IIIA-IIIA in FIG. 1A, and FIG. 1B shows the molding of the point IIIB-IIIB in FIG. It is.

  Next, an embodiment of the present invention will be invented based on the drawings. The oil pan is composed of an outer tank 1 having an upward opening indicated by a one-dot chain line in FIGS. 1 (A) and 1 (B) and an inner tank 2 having an upward opening disposed inside thereof, and between the two tanks, The space 3 is vacant over the entire bottom and circumference. The outer tub 1 is a die-cast product made of aluminum alloy, and the inner tub 2 is an injection-molded product made of synthetic resin (Note that the outer tub 1 may be made into a sheet metal processed product or a resin product. It is possible.) At the upper end of the outer tub 1, a flange 4 is formed over substantially the entire circumference, and the flange 4 is fixed to the lower surface of a cylinder block (not shown).

  Further, an outer flange 5 is provided at a portion of the inner tub 2 where the seal with the outer tub 1 is necessary (where oil should be prevented from falling into the space 3 from above). The seal member 6 made of elastomer is integrally attached. In addition, a large number of pairs of the first communication hole 7 and the second communication hole 8 are formed in the flange 5 at appropriate intervals in the circumferential direction.

  The seal member 6 includes an upper layer 9 that overlaps the upper surface of the flange 5, a lower layer 10 that overlaps the lower surface of the flange 5, and first and second joints that fill the communication holes 7 and 8 and are connected to the upper and lower layers 9 and 10. 11 and 12 and a connecting portion 13 located outside the flange 5 and integrally connected to the upper and lower layers 9 and 10. Therefore, the seal member 6 is held by the flange 5 so as not to be detached by the group of joints 11 and 12 in a state where the seal member 6 is held.

  Furthermore, a lip 14 that comes into contact with the inner peripheral surface of the outer tub 1 is provided on the connecting portion 13 of the seal member 6 (or on the outer edge of the upper layer 9) so as to project obliquely upward. As shown in FIG. 1B, the lip 14 is elastically deformed and comes into contact with the inner peripheral surface of the outer tub 1, thereby sealing between the inner and outer layers 1 and 2.

  As shown in FIG. 1C, the seal member 6 is manufactured by an insert injection molding method using a mold apparatus having an outer mold (cavity) 15 and an inner mold (core) 16 as main elements. . That is, with the outer mold 15 and the inner mold 16 sandwiching the base of the flange 5 of the inner tank 2, the molten elastomer is injected into the space vacated on the mating surfaces of both molds 15 and 16 and then solidified. Thus, the seal member 6 is formed. For this reason, the base of the flange 5 remains exposed for clamping by the molds 15 and 16.

  Instead of the insert molding method, it is also possible to employ a two-color molding method in which the injection molding of the inner tub 2 and the injection molding of the seal member 6 are performed with one mold. The elastomer only needs to have oil resistance and necessary elasticity, and the material is not particularly limited. For example, a polyester-based thermoplastic elastomer (TPC) can be used.

  Although the communication hole is a pair of the first communication hole 7 and the second communication hole 8, as shown in FIG. 2, the first communication hole 7 has an upper portion in a broadened portion 17 that is expanded upward in a trumpet shape. The lower part of the second communication hole 8 is a broadened part 17 that expands downward in a trumpet shape and the upper part is straight. It is a downward spread type. Accordingly, the upper portion of the first joint 11 has a trumpet shape, and the lower portion of the second joint 12 has a trumpet shape.

  The first and second terms relating to the communication holes 7 and 8 and the joints 11 and 12 have no particular meaning, and either one may be called the first or second. When viewed from the group of many communication holes, the upper spreading type and the lower spreading type are arranged alternately. It is also possible to arrange a large number of communication holes at regular intervals. In this case, it is not necessary to distinguish between the first and second, and the upper spread type and the lower spread type are simply arranged alternately. Become.

  As shown in FIG. 3, the inner tub 2 is manufactured by an injection molding method using a mold apparatus including an outer mold (cavity) 18 and an inner mold (core) 19. The communication holes 7 and 8 are formed by the boss portion, but the first boss portion 20 for forming the first communication hole 7 of the downward spreading type is integrally formed with the inner mold 18 as shown in FIG. The 2nd boss | hub part 21 for providing and shape | molding the 2nd communicating hole 8 of an upward expansion type is integrally provided in the outer mold | type 19, as shown to (B).

  Therefore, the positions of the parting lines 22 of the two dies 17 and 18 are different at the locations of the first boss portion 20 and the second boss portion 21. Moreover, since the front end side of the boss | hub parts 20 and 21 is straight shape, the opening edge of the communicating holes 7 and 8 is the edge part 23 which was squared in the location on the opposite side to the expansion part 17. FIG.

  In the above configuration, since the seal member 6 is integrated by injection molding to the flange 5, not only can the manufacturing process be greatly shortened and the cost can be reduced, but also the lip 13 can be detached from the upper layer 11 and the connecting portion 12. Because it is not, it has excellent durability and high reliability. Further, since the upper and lower layers 9 and 10 are connected by the group of joints 11 and 12 and the connecting portion 13, the upper and lower layers 9 and 10 do not come off the flange 5 while being made of a soft elastomer.

  The communication holes 7 and 8 have one opening edge portion as an edge portion 23 and the other opening edge portion as a widening portion 17. 23 and the spread portion 17 are alternately arranged, so that stress is not concentrated only on the edge portion 21 even if any force is applied to the lip 13 of the seal member 6, and high attachment strength is exhibited.

  In particular, as in this embodiment, when the first communication hole 7 that is widened upward and the second communication hole 8 that is widened downward are arranged close to each other and arranged as a set, so to speak, the communication holes with the upper and lower parts spread apart. Since it becomes the same state as having been arranged, it is particularly excellent in a separation preventing function (a function of preventing the joints 11 and 12 from being broken).

  The present invention can be embodied in various ways other than the above-described embodiment. For example, the communication hole and the embodiment may be formed in a tapered shape as a whole. The group of communication holes can be arranged in a staggered arrangement in the circumferential direction while shifting in the width direction of the flange.

  The present invention can actually be embodied in an oil pan of an internal combustion engine. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Outer tank 2 Inner tank 3 Space 5 Inner tank flange 6 Seal member 7, 8 Communication hole 9 Upper layer 10 Lower layer 11, 12 Joint 13 Connection part 14 Lip 15, 16 Mold for forming seal member 17 Communication hole Spreading part 18, 19 Mold 20, 21 Boss part 23 Edge part for molding inner tank

Claims (1)

An outer tank and a resin inner tank, an outward flange is integrally formed on the upper edge of the inner tank, and an elastomeric seal member that contacts the inner surface of the outer tank on the flange Are attached by integral molding,
The inner tank flange is formed with a large number of communicating holes that open up and down in the circumferential direction, and the communicating holes are of an upwardly expanding type in which at least the upper part is expanded upward, and at least the lower part is expanded in the downward direction. While the upper spread type and the lower spread type are mixed and arranged in the circumferential direction,
The sealing member is composed of an upper layer that overlaps the upper surface of the flange, a lower layer that overlaps the lower surface of the flange, and a joint that enters each communication hole of the flange and connects the upper layer and the lower layer.
Two-tank oil pan for internal combustion engines.

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