JPH11173424A - Sealing structure of oil pan joining surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a seal agent reserving clearance while the flange surface of an oil pan is formed by means of press molding which is of advantage to working man-hours and costs, ensure a sufficient seal agent reserving capacity, and provide a high sealing property by a liquid gasket of a double seal structure in which a hardening time of a seal agent is short. SOLUTION: A first flange surface 11 is formed in a flat surface along a total width, a second flange surface 12 is composed of a flat surface part 12a arranged on a center part of a width direction, an inside taper surface 12c, and an outside taper surface 12e. When both flange surfaces 11, 12 are joined with each other, a first seal agent reserving part 31 is formed by the inside taper surface 12c, a second seal agent reserving part 32 is formed by the outside taper surface 12e, and silicone seal agent S is interposed inside and outside so as to form a double seal structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a seal structure for an oil pan mating surface applied to an automatic transmission or the like in which an oil pan is joined to a transmission case.

[0002]

2. Description of the Related Art Conventionally, a seal using a liquid gasket (= liquid packing) obtained by interposing a sealant (silicone sealant or the like) between both flange surfaces and hardening the sealant instead of a molded gasket as a flange seal. As the structure, for example, Japanese Utility Model Application Laid-Open No. Sho 63-20563 and
A seal structure described in JP-A-2-32262 is known.

[0003] In Japanese Utility Model Laid-Open Publication No. Sho 63-20563,
As shown in FIG. 5, in a case where a seal is interposed between the case 1 a and the case 1 b of the transmission case and hermetically joined, the seal is used as the liquid packing 6 and the case 1 a,
There is described a mating surface structure of a transmission case or the like, characterized in that a relief groove 1d is provided on at least one inner side of the mating surface 1b.

[0004] Japanese Utility Model Application Laid-Open No. 62-262262 discloses that
As shown in FIG. 6, in the casing sealing structure in which the flange portions 10 a and 12 a of the two casing members 10 and 12 are connected via the liquid packing 16, the flange portions 1 of both or any one of the casing members 10 and 12 are provided.
Grooves 14, 1 capable of accommodating the ends of liquid packing 16 continuously in the circumferential direction on mating surfaces 10b, 12b of 0a, 12a.
5, there is described a casing seal structure characterized by the provision of a casing seal structure.

[0005]

However, the above-mentioned conventional sealing structure has the following problems.

(1) Since neither of the two members to be joined is a press-formed product, the relief groove 1d and the grooves 14 and 15 serving as the sealant reservoir must be formed by cutting grooves by cutting. This leads to an increase in processing man-hours and an increase in cost.

(2) When the conventional technique is applied to an oil pan in which one of the two members to be joined is a press-formed product,
Since the width of the flange surface of the oil pan is narrow, it is difficult to secure a groove serving as a reservoir for the sealant by press molding. Even if the groove is formed, the groove width is narrow and the groove depth is shallow, so that the amount of pooling of the sealant is insufficient and high sealing performance cannot be expected.

(3) When the pool of the sealing agent is a groove formed inside the flange surface, the area where the sealing agent comes into contact with the outside air is small, and it takes a long time to cure the sealing agent. Incidentally, in the case of a silicone sealant, it hardens by reacting with moisture in the air.

The problem to be solved by the present invention is to eliminate the gap between the sealant and the sufficient capacity of the sealant while forming the flange surface of the oil pan by press forming, which is advantageous in terms of processing steps and cost. It is another object of the present invention to provide a seal structure of an oil pan mating surface that ensures high sealing performance by a liquid gasket of a double seal structure that secures the sealing agent and has a short curing time.

[0010]

[Means for Solving the Problems] (Solution 1) Solution 1 of the above-mentioned problem (Claim 1) is a first oil pan joining method.
A case formed with a flange surface; and an oil pan formed by press molding having a second flange surface formed to match the first flange surface of the case. In a seal structure of an oil pan mating surface using a liquid gasket as a flange seal, a sealing agent is interposed between the two flange surfaces by bolting and applying a sealing agent between the two flange surfaces by bolting. , Flat over the entire width,
The second flange surface has a flat portion at the center in the width direction, an inner tapered surface inclined downward from the flat portion to the inside, and an outer tapered surface inclined downward from the flat portion to the outside. When joining the two flange surfaces, a first sealant reservoir is formed between the inner tapered surface and the first flange surface, and a second sealant reservoir is formed between the outer tapered surface and the first flange surface. It is characterized by having done.

According to a second aspect of the present invention, there is provided a sealing structure for an oil pan mating surface according to the first aspect of the present invention, wherein a portion between the flat portion of the second flange surface and both tapered surfaces is provided. The inner tapered surface and the outer tapered surface are tapered surfaces inclined at a gentle downward inclination angle from the lower end position of the lowered step portion.

According to a third aspect of the present invention, there is provided a sealing structure for an oil pan mating surface according to the first or second aspect, wherein the first sealant accumulating portion is continuously formed over the entire circumference. The second sealant reservoir is continuous between the bolt holes but discontinuous when viewed from the entire circumference.

[0013] (Solution 4) [0013] A solution (4) of the present invention is directed to an automatic transmission in which the case is a transmission case in the seal structure of the oil pan mating surface according to any one of claims 1 to 3. It is characterized by being applied.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) Embodiment 1 is a seal structure for an oil pan mating surface according to the first to fourth aspects of the present invention.

First, the configuration will be described.

FIG. 1 is a sectional view taken along line XX and YY of FIG. 2 showing a seal structure of an oil pan mating surface according to the first embodiment. FIG. FIG. 3 is a plan view showing an oil pan of the automatic transmission to which the applied embodiment is applied. FIG. 3 is a cross-sectional view taken along line ZZ in FIG. 2 showing the oil pan of the automatic transmission to which the joint surface sealing structure of the first embodiment is applied. FIG. 2 is a bottom view showing a transmission case of the automatic transmission to which the joint surface sealing structure of the first embodiment is applied.

3 and 4, 1 is a transmission case (case), 2 is an oil pan, 11 is a first flange surface, 12 is a second flange surface, 21 is a bolt screw hole,
22 is a bolt hole.

The transmission case 1 has a gear train, clutch and brake fastening elements and the like housed therein, and a first flange surface 11 for joining the oil pan 2 is formed at the bottom of the case by milling. ing. Bolt screw holes 21 are formed on the first flange surface 11 at predetermined intervals.

The oil pan 2 is a reservoir for hydraulic oil which is joined to the transmission case 1 in an oil-tight manner.
A main body portion and a second flange surface 12 corresponding to the first flange surface 11 are formed by press molding from one stamped plate. A plurality of bolt holes 22 are punched in the second flange surface 12 at positions corresponding to the bolt screw holes 21.

In joining and fixing the oil pan 2 to the transmission case 1, a silicone sealant S to be described later is applied to one flange surface, and the silicone sealant S is applied between the flange surfaces 11 and 12 by bolting.
And a liquid gasket obtained by curing this is used as a flange seal.

Here, the molded gasket and the liquid gasket will be compared.

In the case of a molded gasket, the parts have the same shape as the gasket, and can be used immediately after assembling, and can be used with an oil-adhesive flange. In addition, it has the disadvantages of requiring high processing accuracy, inventory control of various gaskets, and being expensive.

On the other hand, the liquid gasket has the advantages that there is no settling over time, that the filling can be followed regardless of the processing state of the joint surface, that it is inexpensive, that inventory management can be rationalized, that automation and labor can be saved.

Therefore, a liquid gasket is employed for the joint surface of the oil pan 2 where this advantage is utilized.

FIG. 1 shows the joint sealing structure of the first embodiment.
And FIG.

A feature of the joint surface sealing structure of the first embodiment is that the first flange surface 11 is a flat surface over the entire width, and the second flange surface 12 is a flat portion 1 at the center in the width direction.
2a, an inner tapered surface 12c, and an outer tapered surface 12e. When the two flange surfaces 11, 12 are joined, a first sealant reservoir 31 is formed by the inner tapered surface 12c, and the outer tapered surface 12e is formed. The second sealant reservoir 32
And a double seal structure in which a silicone sealant S is interposed inside and outside.

The second flange surface 12 has a flat portion 12a at the central portion in the width direction, an inner recessed step portion 12b which falls at a sharp angle inward from the flat portion 12a, and a gentle slope from the lower end position of the inner recessed step portion. An inner tapered surface 12c which is inclined with a downward inclination angle (about 15 °), and an outer depression step portion 12 which falls from the flat portion 12a outward at a steep angle.
d, and an outer tapered surface 12e inclined at a gentle downward inclination angle (about 15 °) from the lower end position of the outer stepped portion 12d.

The first sealant reservoir 31 is an open space formed between the inner tapered surface 12c and the first flange surface 11 when the two flange surfaces 11 and 12 are joined.
As shown in the figure, the whole circumference is continuous without any seal breakage.

The second sealant reservoir 32 is an outside air open space formed between the outer tapered surface 12e and the first flange surface 11 when the two flange surfaces 11 and 12 are joined.
As shown in FIG. 2, the space between the bolt holes 22 is continuous but discontinuous when viewed from the entire circumference.

Next, the function and effect will be described.

[At the time of manufacturing the oil pan] At the time of manufacturing the oil pan 2, the second flange surface 1 that matches the main body portion and the first flange surface 11 by press molding from one punched plate.
2 are formed, and a plurality of bolt holes 22 are punched at positions corresponding to the bolt screw holes 21.

At the time of press forming, the second flange surface 12 has a flat portion 12a, an inner stepped portion 12b, an inner tapered surface 12c, an outer stepped portion 12d, and an outer tapered surface 1d.
2e is molded simultaneously. That is, the inner tapered surface 1 serving as the first sealant reservoir 31 and the second sealant reservoir 32
2c and the outer tapered surface 12e can be obtained by press forming, which is advantageous in terms of the number of processing steps and cost as compared with the groove processing by cutting.

Further, there are formed stepped portions 12b and 12d which fall from the flat portion 12a at an abrupt angle inward and outwardly, and a gentle downward inclination angle (about 15 °) from the lower end positions of the two stepped portions 12b and 12d. ), The tapered surfaces 12c and 12e are formed so that the tapered surfaces 12c and 12e do not crack during press forming.
12e can be formed. In other words, when the taper surface is press-formed, if the taper angle is too large, the amount of deformation due to the press-forming increases, and the stress concentration accompanying the deformation partially exceeds the breaking limit, causing material cracks and the like. Will be defective.

[When the oil pan 2 is fixed to the transmission case 1] When the oil pan 2 is fixed to the transmission case 1, the silicone sealant S is injected at a predetermined bead diameter into a substantially central position avoiding a hole in one flange surface. After the application of the sealant is completed, the oil pan 2 is joined and fixed to the transmission case 1 by bolting.

The gap between the two flange surfaces is gradually narrowed by the bolt fastening, and the silicone sealant S having a circular cross section is distorted in cross section, is crushed inward and outward, and moves inward. Silicone sealant S
Are filled in the first sealant reservoir 31 to fill the space, and the silicone sealant S that has moved outwardly is stored in the second sealant reservoir 32 to fill the space.

That is, as shown in FIGS. 1 and 2, the inner first sealant reservoir 31 is continuously filled with the silicone sealant S in an annular shape, and the outer second sealant reservoir 32 is filled. The silicone sealant S is annularly filled except for the bolted portion.

When the silicone sealant S is filled, the second
Since the inner tapered surface 12 c and the outer tapered surface 12 e are formed on the flange surface 12, the filling of the sealant filling space is performed by forming streamlines along the tapered surfaces 12 c and 12 e when the silicone sealant S is filled. The sealant flows, and there is no gap in the sealant pool where the sealant is not filled, and a sufficient sealant pool capacity is secured.

That is, when the inner tapered surface 12c and the outer tapered surface 12e are replaced with a stepped structure with an inner flat surface and an outer flat surface having a step from the flat surface portion 12a, the cross-sectional shape of the sealant reservoir becomes a rectangular cross section. Since there is a corner that intersects at right angles, when the silicone sealant S is filled into the reservoir while flowing, a streamline avoiding this corner is formed, and the corner is formed as a space not filled with the sealant. Become. In addition, in the case of the stepped structure, the sealing agent reservoir has a rectangular cross section in which the cross-sectional area does not change from the center to the end in the case of the stepped structure. Since the cross-sectional shape becomes a trapezoidal cross-section that increases from the center to the end, a large capacity for storing the sealant can be secured.

[Sealant curing action] The silicone sealant S reacts with moisture in the air and cures.

Therefore, the silicone sealant S in the first sealant reservoir 31 is hardened by contact with air from the inside of the transmission case 1 communicating with the outside air by the air breather, and is cured in the second sealant reservoir 32. Since the silicone sealant S communicates with the outside air with a large contact surface due to the large opening shape, it can be cured in an extremely short time.

That is, when the sealant reservoir is formed, if both sides are formed by grooves surrounded by the flange joining surfaces, it is almost insulated from the outside air, and the silicone sealant filled in the grooves is cured. However,
For example, it takes two weeks or more.

[Sealing Action] First, the second flange surface 12
Is formed with a continuous narrow width, the surface tension of the silicone sealant S increases, and the silicone sealant S held strongly between the flange surfaces 11 and 12 seals. The action is exerted.

That is, the sealing action at the joint surface between the oil pan 2 and the transmission case 1 is as follows. The sealing action of blocking the flow of oil that has flowed in is shown by the resilient hardened silicone sealant filled in the first sealant reservoir 31 that is continuous over the entire length.

Even if oil passes through the first sealant reservoir 31, the second sealant reservoir 32
The sealing effect of blocking the passage of the oil that has cleared the first barrier is exhibited by the resilient cured silicone sealant filled in the rubber. Although the second sealant reservoir 32 does not exist in the bolt fastening portion, a large pressing surface pressure acts on the portion due to the bolt fastening force, and almost no gap is formed. A high sealing property is ensured by filling a hardened silicone sealant around the bolt. On the other hand, when the second sealant reservoir 32 is formed at the outer peripheral position of the bolt fastening portion, the outer diameter of the oil pan 2 increases.

That is, since the flange joint surface has a double seal structure in which the two seal barriers of the first sealant reservoir 31 and the second sealant reservoir 32 exist, a high sealing effect is exhibited.

(Other Embodiments) In the first embodiment, an example in which the oil pan mating surface of the automatic transmission is applied to the seal structure has been described. However, the seal structure of the portion that joins the case and the oil pan may be used. For example, the present invention can be applied not only to the automatic transmission but also to various other devices.

[0047]

According to the first aspect of the present invention, a case having a first flange surface for joining an oil pan and a second flange surface matching the first flange surface of the case are formed. An oil pan by press molding was provided, and when joining and fixing the oil pan to the case, a sealing agent was applied to one of the flange surfaces, and the sealing agent was interposed between the two flange surfaces by bolting, and this was cured. In an oil pan mating surface sealing structure using a liquid gasket as a flange seal, the first flange surface is made flat across the entire width, and the second flange surface is lowered inward from the flat portion at the center in the width direction and the flat portion. It has an inclined inner tapered surface and an outer tapered surface inclined downward from the flat portion to the outer direction. When both flange surfaces are joined, the inner tapered surface and the first flange surface are formed. The first sealing agent reservoir is formed between the first and second flanges, and the second sealing agent reservoir is formed between the outer tapered surface and the first flange surface. Therefore, the flange surface forming of the oil pan is advantageous in terms of processing steps and cost. An oil pan that eliminates sealant reservoir gaps while securing sufficient sealant reservoir volume while performing high-pressure press molding, and achieves high sealing performance by a liquid gasket with a double seal structure that has a short curing time for the sealant. The effect of being able to provide a sealing structure of the mating surface is obtained.

According to the second aspect of the present invention, the first aspect is provided.
In the seal structure of the oil pan mating surface described in
A recessed step is formed between the flat surface of the flange surface and the two tapered surfaces, and the inner tapered surface and the outer tapered surface are tapered from the lower end of the recessed step with a gentle downward inclination angle. Therefore, in addition to the above-described effects, it is possible to prevent cracking of the second flange surface during press molding.

According to the third aspect of the present invention, there is provided the first aspect.
Alternatively, in the seal structure of the oil pan mating surface according to claim 2, the first sealant reservoir is continuous over the entire circumference, and the second sealant reservoir is continuous between the bolt holes but is discontinuous when viewed from the entire circumference. Therefore, in addition to the effect of the invention described in claim 1 or claim 2, two seal barriers of the first sealant reservoir and the second sealant reservoir exist without increasing the outer diameter of the oil pan. A high sealing action can be exhibited by the double seal structure.

In the invention according to claim 4, claim 1 is
In the seal structure of the oil pan mating surface according to the third aspect, since the case is applied to an automatic transmission in which the case is a transmission case, in addition to the effects of the first to third aspects, a large amount is sealed in the transmission case. The storage of the transmission hydraulic oil and prevention of external leakage can be achieved by a press-molded oil pan.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view taken along a line XX and a line YY of FIG. 2 showing a seal structure of an oil pan mating surface according to the first embodiment.

FIG. 2 is a plan view showing an oil pan of the automatic transmission to which the joint surface sealing structure of the first embodiment is applied.

FIG. 3 is a sectional view taken along line ZZ in FIG. 2 showing an oil pan of the automatic transmission to which the joint surface sealing structure of the first embodiment is applied.

FIG. 4 is a bottom view showing a transmission case of the automatic transmission to which the joint surface sealing structure of the first embodiment is applied.

FIG. 5 is an overall sectional view and a sectional view of a main part showing a mating surface structure of a conventional transmission case and the like.

FIG. 6 is a sectional view of a casing member and a seal structure to which a conventional casing seal structure is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmission case (case) 2 Oil pan 11 1st flange surface 12 2nd flange surface 12a Flat surface part 12b Inside fall step part 12c Inside taper surface 12d Outside fall step part 12e Outside taper surface 21 Bolt screw hole 22 Bolt hole 31 First seal Agent pool 32 Second seal agent pool S Silicone sealant

Claims (4)

[Claims] 1. An oil pan comprising: a case in which a first flange surface for joining an oil pan is formed; and a press-formed oil pan in which a second flange surface that matches the first flange surface of the case is formed. When joining the oil pan to the case, apply a sealant to one flange surface, insert a sealant between the two flange surfaces by bolting, and align the oil pan using a liquid gasket that has been cured as a flange seal. In the surface sealing structure, the first flange surface is a flat surface over the entire width, and the second flange surface is a flat portion at a center portion in the width direction, an inner tapered surface inclined downward inward from the flat portion, and a flat surface. A first sealing agent reservoir between the inner tapered surface and the first flange surface when the two flange surfaces are joined. Part is formed, the outer tapered surface and the sealing structure of the oil pan mating surface, wherein the forming the second sealing agent reservoir between the first flange surface. 2. The sealing structure of an oil pan mating surface according to claim 1, wherein a stepped portion is formed between a flat portion of the second flange surface and both tapered surfaces, and an inner tapered surface and an outer tapered surface. The oil pan mating surface seal structure, characterized in that the taper surface is inclined with a gentle downward inclination angle from the lower end position of the falling step portion. 3. The sealing structure for an oil pan mating surface according to claim 1, wherein the first sealant reservoir is continuous over the entire circumference, and the second sealant reservoir is continuous between bolt holes. There is a seal structure on the mating surface of the oil pan, which is discontinuous when viewed from the entire circumference. 4. The seal structure for an oil pan mating surface according to claim 1, wherein the case is applied to an automatic transmission in which the case is a transmission case.