JP5989493B2 - Oil seal - Google Patents

Description

  The present invention relates to an oil seal that is a kind of a sealing device according to a sealing technique. The oil seal of the present invention is used, for example, in the field related to automobiles (engines) or in the field of general industrial machinery.

  Conventionally, as shown in FIG. 5, an oil seal using a fabric 51 as a dust lip is known, and this oil seal is used, for example, for sealing around a crankshaft in the field of automobile engines.

In this prior art, the fabric 51 is set smaller than the outer diameter d ₂ of the fabric sliding portion of the initial inner diameter (slinger 52 before insertion inside diameter) d ₁ of the slinger 52, thereby the fabric 51 is tightened When the slinger 52 is inserted, the fabric 51 spreads along the slinger 52, and the contact width with the slinger 52 is secured.

  Therefore, here, since the tightening allowance of the fabric 51 is set large so that the fabric 51 can be uniformly spread on the circumference, and since the stretch load of the fabric 51 itself is high and the tension is high, High sliding torque hinders fuel efficiency.

Moreover, since the fabric 51 has air permeability, it has the following advantages and disadvantages.
advantage····
When a situation occurs in which the pressure in the space 54 between the fabric 51 and the main lip 53 decreases, the pressure decrease is suppressed by the fabric 51 taking in (passing through) air (atmosphere) outside the machine B. Therefore, the pressure of the space 54 between the fabric 51 and the main lip 53 can be reduced and the main lip 53 can be prevented from sticking to the slinger 52 (advantage of taking in air of the fabric).
Difficulties ...
An air leak inspection may be performed at the time of shipment of the oil seal, and the inspection is generally performed by applying a positive pressure from the inside of the machine and measuring the amount of air leakage on the fabric 51 side. In this case, since the fabric 51 releases (passes) air in the above-described conventional technology, the amount of leakage does not become zero even if the oil seal is normal. Therefore, it is necessary to perform inspection after setting a leak tolerance value, and it is not possible to perform a simple inspection in which the leakage threshold is set to zero (difficulty due to air release from the fabric).

JP-A-10-115375 JP-A-7-208610

  In view of the above points, the present invention can reduce sliding torque compared to the case of using a fabric as a dust lip, and achieves the same effect as the advantage of air intake of the fabric without using the fabric. It is another object of the present invention to provide an oil seal that can solve the problems caused by air release from the fabric.

To achieve the above object, an oil seal according to claim 1 of the present invention comprises a combination of a lip seal member fixed to the inner periphery of a shaft hole of a housing and a slinger fixed to a rotating shaft inserted through the shaft hole, An oil seal that suppresses leakage of a sealing fluid inside the machine and prevents dust outside the machine from entering the machine, wherein the slinger is a cylindrical part fitted to the rotating shaft. A flange portion is integrally formed on the inner end portion of the machine toward the radially outer side, and includes a screw groove that performs a pumping action on the outer side end surface of the flange portion toward the radially outer side, and the lip seal A member is disposed on the machine outer side of the main lip, and a main lip that is slidably in close contact with the machine outer end surface of the flange portion of the slinger and seals the sealing fluid. A duster that slidably contacts the outer peripheral surface of the cylindrical portion of the slinger and suppresses the intrusion of dust, and an intermediate lip disposed between the main lip and the duster, A protrusion formed on a contact portion of the slinger with respect to the outer peripheral surface of the cylindrical portion, and the protrusion is slidably in close contact with the slinger. The intermediate lip is made of a rubber-like elastic body, the lip end is directed to the inside of the machine, and the outer periphery of the cylindrical portion of the slinger is extended over the entire circumference with the lip end. And a second projecting portion provided on a portion facing the outer peripheral surface of the cylindrical portion of the slinger, wherein the second projecting portion has a cylindrical shape in the slinger. The dust forms a minute gap between the outer peripheral surface of the is characterized in that it comprises a structure that hardly passes toward the lip end.

  The oil seal according to claim 2 of the present invention is the oil seal according to claim 1, wherein the protrusion provided in the dust lip includes a plurality of concentric circular protrusions each provided with a notch on the circumference. The cutout portions of the annular projections that are adjacent to each other are arranged so as to be displaced on the circumference.

  In the oil seal of the present invention having the above configuration, the dust lip is made of a rubber-like elastic body instead of a fabric, and the dust lip made of the rubber-like elastic body can be formed into a thin wall and easily elastically deformed. The tightening force is reduced while the tightening allowance is the same as that of the fabric. Further, since the protrusion is provided at the contact portion of the dust lip made of rubber-like elastic material with respect to the slinger, the solid contact area with the slinger is reduced. Therefore, it is possible to reduce the sliding torque of the dust lip from these facts.

  Moreover, in this invention, the effect equivalent to the advantage by the air intake of a fabric is implement | achieved as follows.

  In other words, in the present invention, since a thread groove that performs a pumping action radially outward is provided on the outer end surface of the flange portion of the slinger, an excellent sealing effect is exerted against the sealing fluid in the machine. However, when such a thread groove is provided, when the shaft rotates, the pressure in the space between the main lip and the intermediate lip tends to decrease with the pumping action of the thread groove, and a negative pressure is likely to be generated. Easy to hit.

  On the other hand, since the protrusion provided on the dust lip is an annular protrusion provided with a notch in a part of the circumference, air (atmosphere) outside the machine passes through the notch and the dust lip and the intermediate lip. It flows into the space between. The intermediate lip has its lip end in close contact with the slinger over the entire circumference, but since the lip end faces the inside of the machine, air outside the machine (atmosphere) flows into the space between the dust lip and the intermediate lip. The lip end is expanded by the pressure, and air outside the machine (atmosphere) flows into the space between the intermediate lip and the main lip. Therefore, air outside the machine (atmosphere) flows into the space between the intermediate lip and the main lip through such a path, and the pressure in the space between the intermediate lip and the main lip is extremely reduced or negative pressure is generated. It is possible to suppress the main lip from sticking to the slinger.

  In the present invention, the difficulty caused by the air release of the fabric is solved as follows.

  That is, in the present invention, as described above, since the thread groove that performs the pumping action radially outward is provided on the machine outer end face of the flange portion of the slinger, an excellent sealing effect against the sealing fluid in the machine However, when such a thread groove is provided, an air flow path is formed along the thread groove. Therefore, when an air leak inspection is performed at the time of oil seal shipment, the air flowing through the air flow path leaks. Will be detected.

  For this, an intermediate lip is arranged between the main lip and the dust lip, and this intermediate lip has its lip end facing inward and closes to the slinger around the entire circumference with the lip end. The lip passes through the thread groove and seals the air entering the oil seal without blocking the air in the middle of the dust lip. Therefore, when the oil seal is normal, no air leak is detected on the dust lip side, so that it is possible to perform a simple inspection with the air leak threshold set to zero.

  Dustrip has the original function of suppressing the entry of dust outside the machine into the machine. In the present invention, dust is sealed as follows.

In other words, in the present invention, the dust lip is provided with a protrusion, and the protrusion is formed of an annular protrusion having a notch in a part of the circumference, so that there is a possibility that dust may enter from the notch. An intermediate lip is disposed between the dust strips, and the intermediate lip has a second protrusion, and the second protrusion has a structure that forms a small gap with the slinger so that dust does not easily pass toward the end of the lip. I have. Therefore, the labyrinth structure formed by the minute gaps of the second protrusions can prevent the dust outside the machine from entering the inside of the machine.

In addition, as described above, the notches in the protrusions included in the dust lip may be infiltrated with dust from here, and a plurality of annular protrusions provided with notches on a part of the circumference are provided concentrically and mutually. When the notch in the adjacent annular projection is arranged on the circumference displaced, here to such structure of the maze is hardly passed through the dust are provided, which also is possible to hard to penetrate the dust. In this case, even if the dust passes through the notch, it cannot reach the next notch unless it moves on the circumference from there.

  The present invention has the following effects.

  That is, in the present invention, as described above, the dust lip is not a fabric but is formed of a rubber-like elastic body that can be formed into a thin wall and is easily elastically deformed, thereby reducing the sliding torque of the dust lip. It is possible.

  In addition, a combination of a dust lip provided with a projecting portion made of an annular protrusion provided with a notch on a portion of the circumference and an intermediate lip that can be expanded by air (atmospheric) pressure outside the device, ) Is introduced into the space between the intermediate lip and the main lip, it is possible to suppress the pressure in the space between the intermediate lip and the main lip from drastically decreasing or generating negative pressure. Can be prevented from sticking to the slinger.

  Also, when air leak inspection is performed at the time of oil seal shipment, the intermediate lip is sealed in the middle of the oil seal through the screw groove without reaching the dust lip. Air leakage will not be detected on the strip side. Therefore, it is possible to perform a simple inspection in which the threshold value for air leakage is set to zero.

An intermediate lip is disposed between the main lip and the dust lip, and the intermediate lip has a second protrusion, and the second protrusion forms a minute gap with the slinger so that dust passes toward the end of the lip. Since the structure to make it difficult is provided, it is possible to prevent the dust outside the machine from entering the inside of the machine by the labyrinth structure by the minute gaps of the second protrusions.

Furthermore, when a plurality of annular protrusions provided with notches on a part of the circumference are provided in a concentric manner and the notches in adjacent annular protrusions are displaced on the circumference, a structure such as a maze, It is possible to make dust more difficult to enter.

Sectional drawing of the principal part of the oil seal which concerns on the Example of this invention Cross-sectional view of main parts showing a state before the lip seal member in the oil seal is combined with the slinger FIG. 2 is a view in the direction of arrow C in FIG. 1, and is an explanatory diagram of a thread groove in the oil seal Explanatory drawing of the protrusion part in the D direction in FIG. Cross section of the main part of the oil seal according to the conventional example

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a cross section of a main part of an oil seal 1 according to an embodiment of the present invention, and FIG. 2 shows a state before the lip seal member 11 in the oil seal 1 is combined with a slinger 31.

  An oil seal 1 shown in FIG. 1 includes a lip seal member 11 that is fixed to the inner periphery of a shaft hole of a housing (not shown), and a slinger 31 that is fixed to a rotating shaft (not shown) inserted through the shaft hole. In this case, the sealing fluid in the machine A is prevented from leaking out of the machine B and the dust in the machine B is prevented from entering the machine A.

  The slinger 31 is made of a metal material, and is formed by integrally forming a flange portion 31b radially outward at an inner end portion of the tubular portion 31a fitted to the outer peripheral surface of the rotating shaft. A thread groove 32 (see FIG. 3) is provided on the machine end face 31c of 31b to perform a pumping action radially outward. As shown in FIG. 3, the screw groove 32 is a right four-thread screw, that is, a four-way groove that rotates clockwise from the inner side (inner diameter side) to the outer side (outer diameter side). 32 is provided in a range from the bent portion 31d to the tip portion 31e in the flange portion 31b.

  The lip seal member 11 includes an attachment ring 12 and a rubber-like elastic body 13 attached to the attachment ring 12. The mounting ring 12 is made of a metal material, and is formed by integrally forming a flange portion 12b radially inward at the outer end of the tubular portion 12a fitted to the inner peripheral surface of the shaft hole of the housing. The rubber-like elastic body 13 is slidably in close contact with the adherend rubber portion 14 attached to the mounting ring 12 and the machine end surface 31c of the flange portion 31b of the slinger 31 supported by the adherent rubber portion 14. A main lip (side lip) 15 that seals the sealing fluid, and is also supported by the adherend rubber part 14 and disposed outside the machine of the main lip 15, and can slide on the outer peripheral surface of the cylindrical part 31a of the slinger 31. On the outer peripheral surface of the cylindrical portion 31a of the slinger 31 and also disposed between the main lip 15 and the dust lip 16 and supported by the adherend rubber portion 14 An intermediate lip 17 that is slidably in close contact is integrally provided.

  Of these, the main lip 15 is provided with its lip end 15a obliquely toward the inside of the machine and radially outward. The lip 15a slides on the machine end face 31c of the flange portion 31b of the slinger 31. Closely movable.

  As shown in FIG. 2, the dust lip 16 is provided in a thin-walled axially perpendicular plane with its lip end 16 a directed radially inward before being combined with the slinger 31, and is combined with the slinger 31. As shown in FIG. 1, the tightening allowance extends into a cylindrical shape and directs the lip end 16a toward the outside of the machine (one axial direction). In this state, the inner peripheral surface (contact portion) of the cylindrical portion 31a in the slinger 31 Closely slidably contact the outer peripheral surface. Further, since the projection 18 is provided in advance on the inner end surface of the dust lip 16 in the state of FIG. 2, the dust lip 16 can slide on the outer peripheral surface of the cylindrical portion 31 a of the slinger 31 with this projection 18. Closely.

  As shown in FIG. 4, the protrusion 18 is formed by an annular protrusion 19 provided with a notch 20 on a part of the circumference. A plurality of annular projections 19 provided with a notch portion 20 on a part of the circumference are provided concentrically, and the notch portions 20 in the annular projections 19 adjacent to each other are displaced on the circumference. In FIG. 4, the cutout portions 20 are provided at three positions on the circumference of the ring-shaped protrusion 19 at equal intervals. The cross-sectional shape of the annular protrusion 19 is a triangular cross section. In FIG. 4, four annular projections 19 are provided concentrically, and the notches 20 in the annular projections 19 adjacent to each other are displaced by 60 degrees on the circumference.

The intermediate lip 17 is provided with its lip end 17a obliquely toward the inside of the machine and radially inward. The lip end 17a extends around the entire circumference of the intermediate lip 17 on the outer peripheral surface of the cylindrical portion 31a of the slinger 31. Closely slidable. Further, a second protrusion 21 is provided on the inner peripheral surface (opposing portion) of the intermediate lip 17, and the second protrusion 21 forms a minute gap with the outer peripheral surface of the cylindrical portion 31 a in the slinger 31. It has a structure that makes it difficult for dust to pass toward the lip end 17a. The second protrusion 21 is formed by an annular protrusion 22, and a plurality of (for example, two) annular protrusions 22 are provided concentrically. The cross-sectional shape of the annular protrusion 22 is a cross-sectional triangle. In addition, in the 2nd projection part 21 shown in FIG. 2, the notch part 23 is provided in a part on the circumference, However, The intermediate lip 17 is the cylindrical part 31a of the slinger 31 by providing the notch part 23 in this way. The tension against is reduced.

  The oil seal 1 having the above-described configuration is used, for example, to seal around the axis of a crankshaft in an automobile engine, and suppresses leakage of the sealing fluid (oil) in the machine A to the outside B as described above. Prevents dust from outside B from entering machine A. Since the oil seal 1 has the above-described configuration, the following operational effects are exhibited.

  That is, in the oil seal 1 having the above-described configuration, the dust lip 16 is made of a rubber-like elastic body instead of a fabric, and the dust lip 16 made of a rubber-like elastic body can be formed thin and easily elastically deformed. The tightening force is reduced while the tightening allowance is the same as that of the fabric. Further, since the protrusion 18 is provided at the contact portion of the dust lip 16 made of a rubber-like elastic body with respect to the slinger 31, the solid contact area with the slinger 31 is reduced. Therefore, the sliding torque of the dust lip 16 can be reduced from these things.

  Moreover, in the oil seal 1 having the above-described configuration, the same effect as the advantage of taking in air of the fabric is realized as follows.

  That is, in the oil seal 1 having the above-described configuration, since the screw groove 32 that performs a pumping action radially outward is provided on the machine-side end surface 31c of the flange portion 31b of the slinger 31, the sealing fluid in the machine A An excellent sealing effect is exhibited. However, when such a thread groove 32 is provided, the pressure in the space 41 between the main lip 15 and the intermediate lip 17 is accompanied by the pumping action of the thread groove 32 when the shaft rotates. It tends to decrease and negative pressure is likely to occur, and the main lip 15 tends to stick to the slinger 31.

  On the other hand, in the oil seal 1 configured as described above, the protrusion 18 provided on the dust lip 16 is composed of the annular protrusion 19 provided with a notch 20 on a part of the circumference, so that the air outside the machine B (atmosphere) Flows into the space 42 between the dust lip 16 and the intermediate lip 17 via the notch 20. Further, the intermediate lip 17 has its lip end 17a and is in close contact with the slinger 31 over the entire circumference. However, since the lip end 17a faces the inside of the machine, the space 42 between the dust lip 16 and the intermediate lip 17 is moved to the outside B. When the air (atmosphere) flows in, the lip end 17 a is expanded by the pressure, and the air (atmosphere) outside the machine B flows into the space 41 between the intermediate lip 17 and the main lip 15. Accordingly, the air (atmosphere) outside the machine B flows into the space 41 between the intermediate lip 17 and the main lip 15 through such a route, so that the pressure in the space 41 between the intermediate lip 17 and the main lip 15 is extremely reduced. It is possible to suppress the occurrence of negative pressure, and thereby it is possible to suppress the main lip 15 from sticking to the slinger 31.

  Further, in the oil seal 1 having the above-described configuration, the difficulty caused by the air release from the fabric is eliminated as follows.

  That is, in the oil seal 1 having the above-described configuration, as described above, the screw groove 32 that performs the pumping action radially outward is provided on the machine outer end surface 31c of the flange portion 31b of the slinger 31. An excellent sealing effect is exerted on the hermetic fluid, but if such a thread groove 32 is provided, an air flow path is formed through the thread groove 32, so that an air leak is produced when the oil seal 1 is shipped. When the inspection is performed, the air flowing through the air flow path is detected as a leak.

  On the other hand, in the oil seal 1 having the above-described configuration, the intermediate lip 17 is disposed between the main lip 15 and the dust lip 16, and the intermediate lip 17 has its lip 17a facing toward the inside of the machine and the lip 17a. Therefore, the intermediate lip 17 dams and seals the air entering the oil seal 1 through the screw groove 32 on the way without reaching the dust lip 16 so as to be in close contact with the slinger 31. Therefore, when the oil seal 1 is normal, no air leak is detected on the dust lip 16 side, so that a simple test can be performed with the air leak threshold set to zero.

  Further, the dust lip 16 has an original function of suppressing the intrusion of dust from the outside B into the inside A, and the oil seal 1 having the above configuration seals the dust as follows.

That is, in the oil seal 1 having the above-described configuration, the dust lip 16 includes the protrusions 18, and the protrusions 18 are formed of the annular protrusions 19 provided with the notches 20 on a part of the circumference. The intermediate lip 17 is disposed between the main lip 15 and the dust lip 16, and the intermediate lip 17 includes the second protrusion 21, and the second protrusion 21 forms a minute gap between the slinger 31 and the second lip 21. A structure is formed to make it difficult for dust to pass toward the lip end 17a. Therefore, it is possible to prevent the dust outside the machine B from entering the machine A by the labyrinth structure formed by the minute gaps of the second protrusions 21.

  In addition to this, in the oil seal 1 having the above-described configuration, the protrusion 18 provided on the dust lip 16 is provided with a plurality of concentric annular protrusions 19 provided with notches 20 on a part of the circumference and adjacent to each other. The notch portion 20 in the annular projection 19 is disposed so as to be displaced on the circumference, thereby providing a structure such as a labyrinth that makes it difficult for dust to pass therethrough. This also makes it difficult for dust to enter. In this case, even if the dust passes through the cutout portion 20, it cannot reach the next cutout portion 20 unless it moves on the circumference from there, and thus the dust does not easily enter.

DESCRIPTION OF SYMBOLS 1 Oil seal 11 Lip seal member 12 Mounting ring 12a, 31a Tubular part 12b, 31b Flange part 13 Rubber-like elastic body 14 Adhered rubber part 15 Main lip 15a, 16a, 17a Lip end 16 Dustrip 17 Intermediate lip 18 Protrusion part 19, 22 Annular projection 20, 23 Notch portion 21 Second projection portion 31 Slinger 31c Outer end surface 31d Bending portion 31e Tip portion 32 Screw groove A In-machine B Out-of-machine

Claims (2)

It consists of a combination of a lip seal member that is fixed to the inner periphery of the shaft hole of the housing and a slinger that is fixed to the rotating shaft that is inserted through the shaft hole, and prevents leakage of the sealing fluid inside the machine to the outside of the machine and An oil seal that prevents dust from entering the machine,
The slinger is formed by integrally forming a flange portion radially outward at an inner end portion of a cylindrical portion fitted to the rotating shaft, and radially outward on an outer end surface of the flange portion. It has a thread groove that makes a pumping action toward
The lip seal member is slidably in close contact with the outer end surface of the flange portion of the slinger and seals the sealing fluid; and the tubular portion of the slinger is disposed on the outer side of the main lip. A dust lip that slidably comes into close contact with the outer peripheral surface of the dust lip and suppresses the intrusion of dust, and an intermediate lip disposed between the main lip and the dust lip,
The dust lip is made of a rubber-like elastic body, and a protrusion is provided at a contact portion of the slinger with respect to the outer peripheral surface of the cylindrical portion, and the protrusion is slidably in contact with the slinger. It consists of an annular protrusion with a notch on the circumference,
The intermediate lip is made of a rubber-like elastic body, and the lip end faces the inside of the machine, and the lip end is slidably in close contact with the outer peripheral surface of the cylindrical portion of the slinger over the entire circumference. A second projecting portion is provided at a portion of the slinger facing the outer peripheral surface of the cylindrical portion, and the second projecting portion forms a minute gap with the outer peripheral surface of the cylindrical portion of the slinger so that the dust is the lip. An oil seal characterized by having a structure that makes it difficult to pass toward the end. The oil seal according to claim 1,
The protrusion provided in the dust lip is provided with a plurality of concentric annular protrusions provided with notches on a part of the circumference, and the notches in the annular protrusions adjacent to each other are displaced on the circumference. An oil seal characterized by

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