JPS6119241Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of an oil seal having a double lip.

Conventionally, there have been two different types of fluids to be sealed inside a device, and in order to prevent these fluids from mixing with each other, a so-called double lip oil seal 3 as shown in FIG. 1 has been used. In FIG. 1, a double lip oil seal 3 is used between the housing 1 and the rotating shaft 2 to prevent the fluid on the left side of the oil seal from mixing with the fluid on the right side. Lip 31 of the oil seal
The gap 5 between the lip 31 and the lip 31 is not in communication with the atmosphere, the volume of the gap 5 is small, and it is impossible for both lips 31, 31 to exhibit exactly the same sealing effect. One of the fluids to be sealed, such as oil, fills the gap, and eventually the oil from one side flows into the opposite side. In order to prevent this phenomenon, for example, as shown in FIG. 2, two oil seals 3', 3' are assembled with a spacer 12 of an appropriate thickness placed between their backs to form a ventilation passage 6', and the air hole in the housing 1 is assembled. 7, but this method requires separate parts such as spacers to assemble the oil seal, and since the two seals are assembled by gluing, it is extremely difficult to position both seals on a concentric axis. Have difficulty. Another possibility is to sequentially assemble the oil seal, spacer, and oil seal into the housing without assembling them with adhesive, but this would require the oil seal and spacer to be separated during packaging and transportation, increasing the number of steps for the operator, and also requiring assembly. Sometimes it is necessary to incorporate them one by one, and furthermore, there are problems such as difficulty in positioning them with the air holes. There is also a risk of forgetting to install the spacer.

The purpose of the present invention is to eliminate such conventional drawbacks, to communicate the gap between both lips with the atmosphere, and to
To provide an oil seal assembly that allows easy positioning of two seals and also allows easy assembly of the two oil seals without using separate members.

In the present invention, two general-purpose oil seals 4a and 4b are assembled back to back as shown in FIG. This type of general-purpose oil seal is generally formed of a mounting part 42, a back part 43 depending radially from the mounting part 42, and a lip 41 extending axially from one end of the back part 43. As shown in FIG. 4, the oil seals 4a and 4b of the present invention have intermittent locking protrusions 8 and 9 on the back surface 43 thereof, and the oil seal 4b has intermittent locking projections 8 and 9.
are provided with locking protrusions 81 and 91 of the same shape.
Figure 4 shows the locking protrusions 8 of both oil seals 4a and 4b.
and 91 are schematic diagrams showing a state in which locking protrusions 81 and 9 are engaged with each other. That is, the intermittent locking projections are comprised of two types of locking projections, approximately T-shaped projections 8, 81 and approximately L-shaped projections 9, 91, and the locking projections 8, 9 of one oil seal are connected to the locking projections 8, 9 of the other oil seal. The locking projections 81 and 91 are structured to mesh well, and a ventilation passage 6 is formed between the locking projection 9 of one oil seal and the locking projection 91 of the other oil seal. With this locking protrusion, the oil seal assembly of the present invention allows the oil seal to be integrated very easily without using separate parts, reducing the number of parts and work hours, and eliminating assembly defects. have FIG. 5 shows another embodiment, and FIG. 5a is a schematic diagram showing the same state as FIG. 4. The back surface of the oil seal is provided with L-shaped locking protrusions 10a and 10b. When the locking projections 10a, 10b mesh with each other to form an oil seal assembly, the locking projections 10a, 10b are arranged so that a ventilation passage 6 is formed as shown in a partially enlarged perspective view in FIG. 5b. is notch 11
a and 11b are provided. Figures 4 and 5
In the illustrated embodiment, there are a total of four ventilation passages 6, and these ventilation passages 6 communicate with the atmosphere through air holes 7 provided in the housing 1. Therefore both lips 41,
41 and the rotating shaft (removed in Fig. 3), the generation of negative pressure in the gap 5 can be completely prevented. However, there is no risk that the sealed fluid leaking from one lip will be sucked into the other lip. Further, in the illustrated embodiment, the locking protrusions provided on the back surfaces of the left and right oil seals 4a, 4b have the same shape, so there is an advantage that a molding die can be used in common. However, the locking protrusions on both the left and right seals may have a completely different shape, for example, an annular locking protrusion (not shown).The key point is that the locking protrusions on both seals are assembled well and form a ventilation path 6 leading to the outside. Just let it happen. In addition, if the properties of the sealed fluid are different on the left and right sides of the oil seal assembly, or if the left and right oil seals are made of the same rubber material, physical problems will occur, then use a rubber material that has resistance to each sealed fluid. It also has the advantage of being able to be used in combination with appropriately selected vulcanized oil seals.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a conventional double-lip oil seal in use, Figure 2 is a sectional view of two conventional oil seals assembled back to back, and Figure 3 is a cross-sectional view of a conventional double-lip oil seal in use. Cross-sectional views of the oil seal assembly of the invention, FIGS. 4 and 5a, 5
Figure b is a schematic diagram showing the engaged state of the protrusions provided on the back surface of the oil seal of the present invention. 4a, 4b...Oil seal, 5...Gap,
6, 6'... Ventilation path, 7... Air hole, 8, 81,
9, 91, 10a, 10b...Locking protrusion, 11
a, 11b... Notch.

Claims (1)

[Scope of utility model registration request] The back parts of the two oil seals are connected to the atmosphere, and the two oil seals are made up of a mounting part that fits into the housing, a back part that hangs down in the radial direction from the mounting part, and a lip that extends in the axial direction from one end of the back part. An oil seal assembly forming a ventilation passage, characterized in that each of the oil seals is provided with a locking protrusion on its back surface and combined with each other.