JPH0723661Y2 - Sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of use) The present invention relates to a sealing device used between a housing and a shaft that are concentrically combined with each other to perform relative rotational movement. The invention relates to a structure of a sealing device capable of preventing mutual mixing of different kinds of target oils to be sealed, which are formed in both chambers.

(Problems to be solved by the prior art and the invention) A sealing device used between a housing and a shaft that are concentrically combined with each other to perform a rotary operation, and in particular, both spaces formed in parallel in an axial direction. As a means for sealing different kinds of oils to be sealed in the room, as shown in FIG. 7, a sealing device in which two sealing lips are assembled back to back is used.

The sealing device shown in the figure has an annular mounting portion 21 having a substantially L-shaped cross-sectional shape and mounted on the housing 1, and a substantially cylindrical shape made of a rubber-like elastic material. It has a first seal lip 22 and a second seal lip 23 that are adhered to the inner end of the mounting portion 21 and slide on the peripheral surface of the shaft 2, and by the first seal lip 22 to the left on the same as above. While sealing the target oil in the first oil chamber A, the second seal lip 23 seals the target oil in the second oil chamber B on the right side in the drawing. Due to the suction action generated by the first seal lip 22 and the second seal lip 23 at the time of operation, the inside of the annular space 24 formed between the two seal lips 22 and 23 is in a negative pressure state, and both seal lips 22. , 23 is strongly pressed by the peripheral surface of the shaft 2 and wears early, so As shown in the figure, the annular mounting portion 21 has a two-part structure, and a vent hole 25 is provided at the joint portion.
A means for connecting the annular space 24 to the second oil chamber B on the right side in the drawing to prevent the pressure in the annular space 24 from decreasing is used.

However, in the sealing device provided with the vent hole 25, the splash oil in the second oil chamber B flows into the annular space 24 through the vent hole 25 and is sucked by the first seal lip 22. There was a risk of mixing with the oil in the first oil chamber A.

The applicant has attached a guide piece 26, which has a conical shape and faces the inner peripheral surface of the second seal lip 23, to the first seal lip 22 so that the splash oil that has entered the ventilation hole 25 is sealed in the second seal. lip
We succeeded in leading it to the 23rd side and returning it to the second oil chamber B.

However, even in the sealing device provided with the above-mentioned guide piece 26, the ventilation hole 25 can be formed by repeating the operation and the stop.
Since the oil that has passed through is accumulated in the annular space 24, it may flow into the first oil chamber A side, and if the usage period becomes long, the sludge in the oil will be discharged to the second side by the guide piece 26. The second seal lip 23 in order to be guided to the seal lip 23 side of the
Is shortened compared to the first seal lip 22.

An object of the present invention is to provide a structure of a sealing device which can effectively prevent mixing of two kinds of oils to be sealed and can prevent wear of a seal lip due to accumulation of sludge.

(Means for Solving Problems) The present invention is a sealing device that seals between a housing and a shaft rotating relative to the housing in consideration of the problems in the above-described conventional sealing device. , A first seal lip that extends to the first oil chamber side on the inner circumference of the radial portion of the outer cylinder fixed to the housing side and slides on the peripheral surface of the shaft, and is fixed to the outer circumference cylindrical portion inner circumference of the outer cylinder In the sealing device having a second seal lip that extends to the second oil chamber side and slides on the peripheral surface of the shaft on the inner circumference of the radially inner portion of the inner cylinder, the first seal lip and the second seal lip are provided. A radial outer side of an annular space formed between a seal lip and the radial direction inner peripheral portions of the inner and outer cylinders abutting each other between the outer cylinder and the inner cylinder. A ring-shaped vacant space that is separated from the ring-shaped vacant space Vent slits that connect the annular space and the second oil chamber are formed between the fitting portions of the outer cylinder and the inner cylinder and in the axial half cut section of the annular space, A reflux slit for communicating the annular space and the second oil chamber is formed between the fitting portions of the outer cylinder and the inner cylinder and in a half-section under the shaft of the annular space.
The inner and outer cylinders are provided with a ventilation means for communicating the annular space and the annular space in the inner peripheral portions of the radial direction portions which are in contact with each other, and the annular space is provided with a gutter.

(Operation) In the sealing device of the present invention having the above-mentioned configuration,
An annular space formed radially outward of the annular space, a ventilation slit for communicating the upper part of the annular space with the second oil chamber, and a ventilation means for communicating the lower part of the annular space with the annular space. However, the negative pressure is effectively prevented from being generated in the annular space, and the structure in which the annular space and the annular space are separated prevents the inflow of the splash oil that has entered the annular space into the annular space, and The return slit that connects the lower part of the annular chamber and the second oil chamber recirculates the splash oil that has entered the annular chamber to the second oil chamber.

A mode in which a jammer plate is attached to the upper side of the shaft in the rotational direction of the shaft in the vicinity of the opening on the second oil chamber side of the ventilation slit that communicates the upper part of the annular chamber with the second oil chamber, or the ventilation slit In the aspect in which the outer cylinder and the inner cylinder forming the return slit are provided with flanges, respectively, oil splashes or oil films generated in the second oil chamber pass through the ventilation slit and enter the annular space. It is prevented from invading.

(Embodiment) In the embodiment shown in FIG. 1, the outer cylinder 3 attached to the housing 1, the first radial portion 4 extending from the end of the outer cylinder 3, and the first radial portion 4 are bonded. A first seal member having a first seal lip 5, an inner cylinder 6 inserted into the outer cylinder 3, a second radial portion 8 extending from an end of the inner cylinder 6, and a second
And a second seal member having a second seal lip 9 adhered to the radial portion 8 of the shaft 2 are combined with each other to form the return cavity 7 on the housing 1 side, and the shaft 2
An annular space 10 is formed on the side, and a ventilation slit 12 for communicating the upper part of the annular space 7 and the second oil chamber B is provided above the fitting portion of the outer cylinder 3 and the inner cylinder 6. Below the fitting portion, a reflux slit 13 that connects the lower portion of the annular space 7 and the second oil chamber B is provided, and the side surface of the second radial portion 8 has a substantially conical shape. A gutter 14 that extends into the annular space 7 and guides the splashed oil that has entered through the ventilation slit 12 to the lower part of the annular space 7 is provided, and the side surface of the first radial portion 4 has a second radial direction. The second radial portion 8 is provided with an annular projection 11 that abuts the side surface of the portion 8.
A ventilation groove 15 is formed so as to extend above the inner peripheral surface of the second seal lip 9 from the side surface thereof to connect the annular space 7 and the annular space 10.

In another embodiment shown in FIG. 2, an annular projection 11 for separating the annular space 7 and the annular space 10 is attached to the second radial portion to guide the invading splash oil to the lower part of the annular space. 14 is not provided, and a vent pipe 15 'penetrating the annular projection 11 is provided as a ventilation means for communicating the annular space 7 and the annular space 10 with each other, and the vent pipe is in a protruding state, so that the annular The inner surface of the vacant room 7 becomes a gutter 14. Except for these points, the configuration is similar to that of the embodiment shown in FIG.

In another embodiment of FIG. 3, the first sealing member and the second sealing member, which are combined with each other, are constructed in the same manner as the embodiment of FIG. In the vicinity of the opening of the ventilation slit 12 communicating with the oil chamber B on the second oil chamber B side, the rotation direction of the shaft 2 will be better described in detail in the fourth section.
A substantially rod-shaped baffle plate 16 as shown in the figure or a cover type baffle plate 16 as shown in FIG. 5 is attached.

In another embodiment of FIG. 6, the first seal member and the second seal member, which are combined with each other, are configured in the same manner as in the embodiment of FIG. The inner cylinder 6 of the second seal member is provided with flanges 17 and 18, respectively, and bends a ventilation slit 12 and a recirculation slit 13 that connect the annular space 7 and the second oil chamber B to each other. .

With respect to the embodiment shown in FIGS. 1 and 2, the embodiment shown in FIGS. 3 to 5 and the embodiment shown in FIG. 6, a test was conducted for 1 hour at a rotation speed of the shaft 2 of 3000 rpm to obtain a second oil. It was confirmed whether or not the oil in the chamber B moved into the first oil chamber A.

The oil level in the first oil chamber A is set equal to the height of the central axis of the shaft 2, and the height of the oil level in the second oil chamber B with respect to the lower end surface of the shaft 2 is set to 0,1,2. It was changed to 3,3,4,5,6 mm.

In the embodiment shown in FIGS. 1 and 2, the height of the oil surface in the second oil chamber B relative to the lower end surface of the shaft 2 is 0 to 3 mm.
Oil is not seen to move from the second oil chamber B side into the first oil chamber A, and the oil level in the second oil chamber B is 4 to 6 mm. Was recognized.

In the embodiment of FIGS. 3 to 5 and 6, the second
No oil movement was observed in all cases where the height of the oil surface in the oil chamber B was 0 to 6 mm.

(Effects of the Invention) As described above, the sealing device according to the present invention is provided radially outward of the annular space formed between the first seal lip and the second seal lip that slides on the peripheral surface of the shaft. An annular space that is separated from the annular space and that connects the upper part of the annular space and the second oil chamber with a ventilation slit; and connects the lower part of the annular space with the second oil chamber By providing a structure for forming a circulation slit and a ventilation means for communicating the annular space and the annular space, negative pressure is prevented from being generated in the annular space between both seal lips, and the ventilation slit is passed through. The splash oil that has entered the annular chamber is blocked from flowing into the annular chamber, guided to the lower part of the annular chamber, and returned to the second oil chamber through the return slit. The second oil chamber penetrated into the annular space seen in the equipment The possibility that the splash oil on the side will be mixed into the first oil chamber due to the suction action of the first seal lip is eliminated, and further the early wear of the seal lip due to the accumulation of sludge in the annular space is effectively prevented.

[Brief description of drawings]

1 is a sectional view of an embodiment of the present invention, FIG. 2 and FIG.
FIG. 4 is a sectional view of another embodiment of the present invention, FIGS. 4 and 5 are partial front views of the embodiment of FIG. 3, and FIG. 6 is another embodiment of the present invention. Sectional view of Example, No. 7
FIG. 1 is a sectional view of an example of a conventional sealing device. 1 ... Housing, 2 ... Shaft, 3 ... Outer cylinder, 4 ...
... first radial portion, 5 ... first seal lip, 6 ...
Inner cylinder, 7 ... Annular chamber, 8 ... Second radial portion, 9 ...
2nd seal lip, 10 ... annular space, 11 ... annular protrusion, 12 ... ventilation slit, 13 ... reflux slit, 14
…… Gutter, 15 …… Ventilation groove, 15 ′ …… Vent pipe, 16 ……
Jamming plate, 17 ... Flange, 18 ... Flange, A ... First oil chamber, B ... Second oil chamber, 21 ... Annular mounting part, 22 ...
… First seal lip, 23 …… Second seal lip, 24
…… Annular void, 25 …… Vent hole, 26 …… Guide piece.

Claims (3)

[Scope of utility model registration request] 1. A seal device for sealing between a housing (1) and a shaft (2) rotating relative to the housing (1), the outer cylinder (3) fixed to the housing (1) side. A first seal lip that extends to the first oil chamber (A) side on the inner circumference of the radial portion (4) and slides on the peripheral surface of the shaft (2), and on the outer peripheral cylindrical portion of the outer cylinder (3). The second oil chamber (B) is provided on the inner circumference of the radial portion (8) of the inner cylinder (6) fixed to the circumference.
A sealing device having a second seal lip extending to the side and sliding on the peripheral surface of the shaft (2), between the first seal lip (5) and the second seal lip (9). The radial inner portions of the inner and outer cylinders are in contact with each other between the outer cylinder (3) and the inner cylinder (6) radially outward of the formed annular space (10). Thus, an annular space (7) separated from the annular space (10) is provided, and the ventilation slit (12) communicating the annular space (7) and the second oil chamber (B) is provided. It is formed between the fitting portion of the outer cylinder (3) and the inner cylinder (6) and on the axial partial cut-away section of the annular space (7), and the annular space (7) and the second oil are formed. A reflux slit (13) communicating with the chamber (B) is provided between the fitting portion of the outer cylinder (3) and the inner cylinder (6) and a half of the axial empty chamber (7) below the shaft. Formed in cross-section, the vent means for communicating the annular air chamber (7) and the annular cavity and (10) in said radially inner peripheral portion which abut each other of the inner and outer tubes (1
5, 15 ') are formed, and the gutter (14) is provided in the annular chamber (7).
A seal device characterized by being provided with. 2. The gutter (14) has a conical shape extending radially outward from the radial portion (8) of the inner cylinder (6) and into the annular space (7). The sealing device according to the first section. 3. The ventilation means (15) is a ventilation groove extending in a radial direction provided in the radially inner peripheral portions of the inner and outer cylinders of the inner and outer cylinders that abut each other. The sealing device according to the second aspect.