JP2008196568A - Sealing device for water pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the sealing performance and the wear resistance of a sealing device for a water pump attached between a housing 2 and a shaft 3 in order to prevent a sealed fluid such as LLC from leaking from inside A to outside B of a machine. <P>SOLUTION: The sealing device is provided with a seal lip 24 closely contacting a sleeve 11 fixed to the housing 2 and fixed to the shaft 3, in a sliding manner, and a labyrinth seal 41 set on the seal lip 24 inside A of the machine by the sleeve 11. A second seal lip 33 is disposed on the seal lip 24 outside B of the machine. A pumping mechanism 51 for exerting a returning pumping action is disposed on at least one of a pair of axially opposed surfaces constituting the labyrinth seal 41. A pumping mechanism 61 also is disposed on at least one of sliding surfaces of the seal lip 24 and the sleeve 11 sliding to each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sealing device according to a sealing technique, and more particularly to a sealing device suitable for use in a shaft seal portion of a water pump. The sealing device of the present invention is used for, for example, a water pump for cooling an automobile engine, or used for other cooling water pumps.

  Conventionally, a sealing device 101 shown in FIG. 4 is known as a sealing device used in this type of water pump. The sealing device 101 is fixed to the housing 102 and is slidably in close contact with the shaft 103. By arranging a plurality of lips 104 side by side, a sealing fluid such as LLC is sealed so as not to leak from the inside A to the outside B.

However, according to the above prior art, the sealing operation which is the main function depends solely on the sliding operation of each seal lip 104, and therefore there is a limit to the sealing performance that can be exhibited. In addition to sealing performance, it is necessary to pay attention to the following points as a sealing device for a water pump.
(1) Since a pressure of about 0.2 MPa acts from the inside as the sealing fluid pressure, it is necessary to consider pressure resistance.
(2) Since the seal lip is easily worn by water lubrication, it is necessary to consider wear resistance.
(3) Since foreign matters such as cast sand, rust, or sand particles existing in the pump are mixed in the water and easily wear the seal lip, it is necessary to consider wear resistance also in this respect.

JP 2002-310095 A

  In view of the above, the present invention has an object to provide a sealing device capable of improving its sealing performance and wear resistance in a sealing device for a water pump that seals a sealing fluid such as LLC. .

  To achieve the above object, a sealing device according to claim 1 of the present invention is a water pump sealing device mounted between a housing and a shaft so that a sealing fluid such as LLC does not leak from the inside of the machine to the outside of the machine. And a seal lip that is slidably in close contact with a sleeve fixed to the shaft, and a labyrinth seal set by the sleeve inside the seal lip.

  According to a second aspect of the present invention, there is provided a sealing device for a water pump according to the first aspect, wherein a second seal lip is provided outside the seal lip.

  According to a third aspect of the present invention, there is provided the sealing device for a water pump according to the second aspect, wherein a metal ring for fixing the seal lip to the housing is provided, and an axial end of the metal ring is provided. The caulking end portion for preventing the second seal lip from coming off in the axial direction is provided integrally.

  According to a fourth aspect of the present invention, there is provided a sealing device for a water pump according to any one of the first to third aspects, wherein the sealing device is returned to at least one of a pair of opposing surfaces in the axial direction constituting the labyrinth seal. A pumping mechanism that exhibits a pumping action is provided.

  A sealing device according to claim 5 of the present invention is the sealing device for a water pump according to any one of claims 1 to 4, wherein at least one of the sliding surfaces of the seal lip and the sleeve that slide relative to each other is provided. A pumping mechanism that exhibits a return pumping action is provided.

  Furthermore, a sealing device according to a sixth aspect of the present invention is the sealing device for a water pump according to any one of the first to fourth aspects, wherein at least one of the sliding surface of the seal lip and the sleeve sliding with each other is provided. The present invention is characterized in that a foreign matter trapping mechanism is provided that exhibits the action of catching the foreign matter that has been bitten.

  In the sealing device according to the first aspect of the present invention having the above-described configuration, since the seal lip is provided so as to be slidably in close contact with the sleeve fixed to the housing and fixed to the shaft, the seal lip is sealed fluid. Since the labyrinth seal is set by the sleeve on the inner side of the seal lip, this labyrinth seal exerts the action of reducing the sealing fluid pressure. The labyrinth seal forms a narrow axial gap between the sleeve and the parts facing it, and exerts a pressure reducing action or a sealing action because fluid does not easily pass through the narrow gap. Therefore, since the sealing lip seals a relatively low pressure sealing fluid decompressed by the labyrinth seal, the sealing function by the sealing lip can be relatively enhanced, and the sealing performance can be improved.

  In addition, since the labyrinth seal is disposed on the inner side of the seal lip, foreign matters such as cast sand existing on the inner side of the machine hardly pass through the labyrinth seal and do not easily reach the seal lip. Accordingly, it is possible to prevent foreign matter from entering the lip sliding portion and wearing the seal lip early. If the labyrinth seal reduces the sealing fluid pressure, the load acting on the seal lip is reduced, and the contact surface pressure of the seal lip is reduced. Therefore, it is possible to reduce the damage received by the seal lip even if foreign matter enters the lip sliding portion, and thus it is possible to suppress the early wear of the seal lip from this point as well. Thus, the wear resistance of the seal lip can be improved.

  In the present invention, the sleeve which is a constituent part serves as both a counterpart part for sliding with respect to the seal lip and a part for forming a labyrinth seal.

  Further, in the sealing device according to the second aspect of the present invention having the above-described configuration, the same function and effect as those of the first aspect are exhibited, and the second seal lip is provided outside the machine of the seal lip. When fluid passing through the sealing lip is generated, it is possible to seal this fluid with the second sealing lip. Therefore, the sealing performance of the entire sealing device can be further improved.

  In the sealing device according to claim 3 of the present invention, the end of the metal ring for fixing the seal lip to the housing is integrally formed with the end of the crimp for preventing the second seal lip from coming off in the axial direction. Therefore, even if the seal lip and the second seal lip are assembled without being bonded to each other, the components are firmly combined with each other, and the second seal lip is not dropped from the seal lip. Therefore, it is possible to firmly combine components and improve the handling workability thereof.

  In the sealing device according to claim 4 of the present invention, at least one of the pair of facing surfaces in the axial direction constituting the labyrinth seal is provided with a pumping mechanism that exerts a return pumping action. It is possible to return the sealing fluid to the inside of the machine by the fluid pressure, so that the sealing performance of the entire sealing device can be further improved. In addition, since the foreign matter can be removed by the return fluid pressure, it is possible to suppress the seal lip from being worn early by the foreign matter.

  Further, in the sealing device according to claim 5 of the present invention, since a pumping mechanism that exhibits a return pumping action is provided on at least one of the sliding surface of the seal lip and the sleeve that slide relative to each other, it occurs during rotation. The sealing fluid can be returned to the inside of the machine by the return fluid pressure, so that the sealing performance of the entire sealing device can be further improved. In addition, since the foreign matter can be removed by the return fluid pressure, it is possible to suppress the seal lip from being worn early by the foreign matter.

  Furthermore, in the sealing device according to claim 6 of the present invention, there is provided a foreign matter trapping mechanism that exhibits an action of capturing foreign matter caught in at least one of the sliding surface of the seal lip and the sleeve that slide with each other. For this reason, when a foreign substance enters the sliding portion, it can be caught in the trap mechanism and captured. Therefore, it is possible to effectively suppress the seal lip from being worn out early by foreign matter or from leaking out to the outside.

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

First embodiment ...
FIG. 1 shows a cross section of a main part of a sealing device 1 according to a first embodiment of the present invention. The sealing device 1 according to the embodiment includes a water pump for cooling an automobile engine so that LLC (long life coolant) as a sealing fluid (liquid) does not leak from the inside (sealing fluid side) A to the outside (atmosphere side) B. And is configured as follows.

  That is, first, a seal lip (first seal lip) 24 is provided which is fixed to the inner periphery of the shaft hole of the housing 2 and slidably close to the outer peripheral surface of the sleeve 11 fixed to the outer periphery of the shaft 3. A labyrinth seal (labyrinth mechanism) 41 is set by the sleeve 11 on the inner side A of the seal lip 24. A second seal lip 33 is provided on the outer side B of the seal lip 24. The seal lip 24 is fixed to the inner periphery of the shaft hole of the housing 2 by the fitting allowance of the metal ring 25, and the second seal lip 33 is prevented from coming off at the axial end of the metal ring 25 in the axial direction. The caulking end portion 25c is integrally formed.

  Moreover, the sealing device 1 according to this embodiment includes a sleeve 11, a first lip seal member 21, and a second lip seal member 31 as its components.

  Of these, the sleeve 11 is integrally formed with a flange portion 13 outwardly in the radial direction at the inner end of the relatively long cylindrical fixing portion 12 fixed to the outer periphery of the shaft 3. A labyrinth seal forming portion (detailed later) 14 is provided as a part thereof. The sleeve 11 is formed of a single metal plate (sheet metal press product) made of SUS or the like.

  The first lip seal member 21 is integrally formed with a flange portion 23 radially inwardly at the inner end of the cylindrical fixing portion 22 fixed to the inner periphery of the shaft hole of the housing 2. The first seal lip 24 that is slidably in close contact with the outer peripheral surface of the cylindrical fixing portion 12 of the sleeve 11 is integrally formed. The first lip seal member 21 has a rubber-like elastic body 26 attached to a metal ring 25 in which a flange portion 25b is integrally formed radially inwardly at the inner end of the tubular portion 25a (vulcanization adhesion). The rubber-like elastic body 26 causes the outer peripheral rubber portion 26a attached to the outer peripheral surface of the cylindrical portion 25a of the metal ring 25 and the inner peripheral surface of the cylindrical portion 25a of the metal ring 25. Arranged on the inner peripheral rubber part 26b, the flange inner part 26b attached to the inner and outer end faces of the flange part 25b of the metal ring 25 and the inner peripheral part, and the inner peripheral side of the flange rubber part 26c. The first seal lip 24 is integrally formed. The outer peripheral and inner peripheral rubber portions 26 a and 26 b form the cylindrical fixing portion 22 together with the cylindrical portion 25 a of the metal ring 25. The flange rubber portion 26 c forms the flange portion 23 together with the flange portion 25 b of the metal ring 25. The first seal lip 24 is configured so that the pressure receiving surface 24a faces the machine inner side A and is pressed against the outer peripheral surface of the cylindrical fixing portion 12 of the sleeve 11 when receiving the sealing fluid pressure on the pressure receiving surface 24a. Yes. Furthermore, when the second lip seal member 31 is fixed (fitted) to the inner periphery of the cylindrical fixing portion 22 of the first lip seal member 21, the second lip seal member 31 is axially attached to the metal ring 25. A caulking end portion 25c for preventing it from slipping out is formed integrally with the end portion on the machine outer side of the cylindrical portion 25a.

  The second lip seal member 31 is provided on the inner peripheral surface of the cylindrical fixing portion 32 fixed to the inner periphery of the cylindrical fixing portion 22 of the first lip seal member 21 and on the outer peripheral surface of the cylindrical fixing portion 12 of the sleeve 11. A second seal lip 33 that is slidably in close contact is integrally formed, and a third seal lip 34 is integrally formed on the outside B of the machine. The second lip seal member 31 is made of a single rubber-like elastic body, and the cylindrical fixing portion 32 and the second and third seal lips 33, 34 are integrally formed by the rubber-like elastic body. . Similarly to the first seal lip 24, the second and third seal lips 33, 34 have their pressure-receiving surfaces 33a, 34a directed toward the machine inner side A, and the sleeves are subjected to a sealing fluid pressure at the pressure-receiving surfaces 33a, 34a. It is comprised so that it may press on the outer peripheral surface of the 11 cylindrical fixing | fixed part 12. FIG.

  The labyrinth seal 41 is set as a minute axial gap between the sleeve 11 and the first lip seal member 21. That is, the labyrinth seal forming portion 14 is provided as a part of the flange portion 13 of the sleeve 11, and the labyrinth seal 41 is set between the labyrinth seal forming portion 14 and the inboard end surface of the first lip seal member 21. . The labyrinth seal forming portion 14 is integrally formed at the outer peripheral end portion of the flange portion 13 toward the machine outer side B, and is integrally formed radially outward at the machine outer end portion of the cylindrical portion 14a. Since the outer peripheral end of the outer peripheral flange 14b is opposed to the inner end of the flange 23 of the first lip seal member 21 with a slight axial gap, A labyrinth seal 41 is provided.

  The first lip seal member 21 and the second lip seal member 31 fixed to the housing 2 side are each manufactured separately and assembled without using an adhesive.

  When the sealing device 1 having the above configuration is mounted on the shaft seal portion of the water pump, the first seal lip 24 on the machine inner side A forms a primary seal, and the second and third seal lips 33 and 34 on the machine outer side B are two. The labyrinth seal 41 that forms the secondary and tertiary seals and further acts as a pressure reducing mechanism is disposed on the machine inner side A of the first seal lip 24. Therefore, in the sealing device 1, the following effects are exhibited.

  That is, first, in the sealing device 1 configured as described above, a seal lip 24 that is fixed to the inner periphery of the shaft hole of the housing 2 and is slidably in close contact with the outer peripheral surface of the sleeve 11 fixed to the outer periphery of the shaft 3 is provided. Therefore, the seal lip 24 exerts an action of sealing the sealing fluid. Since the labyrinth seal 41 is set by the sleeve 11 on the inner side A of the seal lip 24, the labyrinth seal 41 has a sealing fluid pressure. Depressurizes the pressure. Therefore, since the former seal lip 24 seals the relatively low-pressure sealing fluid decompressed by the latter labyrinth seal 41, the sealing function by the seal lip 24 can be relatively enhanced, and thus the sealing performance can be improved. Can be improved.

  Further, since the labyrinth seal 41 is arranged on the inner side A of the seal lip 24, foreign matters such as cast sand existing on the inner side A do not easily pass through the narrow labyrinth seal 41, and therefore reach the seal lip 24. It is difficult. Accordingly, it is possible to prevent foreign matter from entering the lip sliding portion and premature wear of the seal lip 24. Further, when the labyrinth seal 41 reduces the sealing fluid pressure, the load acting on the seal lip 24 is reduced, and the contact surface pressure of the seal lip 24 is reduced. Therefore, even if a foreign substance enters the lip sliding portion, the damage received by the seal lip 24 can be reduced. Therefore, it is possible to suppress the early wear of the seal lip 24 from this point. Therefore, the wear resistance of the seal lip 24 can be improved by these.

  Further, since the second and third seal lips 33 and 34 are provided on the outside B of the seal lip 24, the sealing fluid that has passed through the seal lip 24 is transferred to the second and third seal lips 33 and 34. It is possible to seal. Therefore, the sealing performance of the sealing device 1 as a whole can be further improved.

  Further, the second lip seal member 31 having the second and third seal lips 33 and 34 at the axial end portion of the metal ring 25 for fixing the first lip seal member 21 having the seal lip 24 to the housing 2 is pivoted. Since the crimping end portion 25c for preventing it from coming off in a direction is integrally formed, even if the first and second lip seal members 21 and 31 are assembled without being bonded to each other, the components are firmly combined with each other. The second lip seal member 31 does not fall off. Therefore, it is possible to firmly combine components and improve the handling workability thereof.

  The sealing device 1 according to the first embodiment may be added or changed as follows.

Second embodiment ...
In the first embodiment, the seal lip 24 is made of a rubber-like elastic body. Instead, the seal lip 24 is made of resin. In the example of FIG. 2, the seal lip 24 is made of a single piece of resin (plate-like resin) such as PTFE, and the outer peripheral portion 24 b of the flange portion 23 of the first lip seal member 21 and the second lip seal member 31. It is sandwiched between the cylindrical fixing part 32. In addition, a metal ring 35 is embedded in the second lip seal member 31 in order to strengthen this pinching.

Third embodiment ...
In addition to the configuration of the first embodiment, a pumping mechanism that exhibits a return pumping action is provided on at least one of the pair of axially facing surfaces that constitute the labyrinth seal 41. In the example of FIG. 3, the pair of facing surfaces in the axial direction constituting the labyrinth seal 41 is composed of the machine-side end face of the labyrinth seal forming portion 14 in the sleeve 11 and the machine-side end face of the flange portion 23 in the first lip seal member 21. Of these, the pumping mechanism 51 is provided on the machine inner end face of the flange portion 23, and more specifically, the pumping mechanism 51 is provided on the machine inner end face of the flange rubber part 26c. The pumping mechanism 51 is composed of one or a plurality of spiral grooves (screw grooves), and pushes the fluid back to the machine interior A by a return pump action generated during rotation and discharges foreign matter.

  Further, in addition to the configuration of the first embodiment, a pumping mechanism that exerts a return pumping action is provided on at least one of the seal lip 24 and the sliding surface of the sleeve 11 that slide with each other. In the example of FIG. 3, the sliding surfaces that slide with each other are formed by the inner peripheral surface of the seal lip 24 and the outer peripheral surface of the cylindrical fixing portion 12 in the sleeve 11. A mechanism 61 is provided. As described above, the pumping mechanism 61 is composed of one or a plurality of spiral grooves (screw grooves), and pushes the fluid back to the machine interior A by a return pump action generated during rotation, and discharges foreign matter.

  Further, at least one of the sliding surfaces of the seal lip 24 and the sleeve 11 may be provided with a foreign matter trapping mechanism (not shown) that exhibits the action of catching the caught foreign matter instead of the pumping mechanism 61. . The foreign matter trapping mechanism is composed of one or a plurality of annular grooves (in the case of a plurality of foreign grooves, it becomes a parallel groove), and traps (holds) foreign substances by biting them into the grooves.

Sectional drawing of the principal part of the sealing device which concerns on 1st Example of this invention. Sectional drawing of the principal part of the sealing device which concerns on 2nd Example of this invention. Sectional drawing of the principal part of the sealing device which concerns on 3rd Example of this invention. Sectional drawing of the sealing device which concerns on a prior art example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealing device 2 Housing 3 Shaft 11 Sleeve 12, 22, 32 Cylindrical fixing part 13,23,25b Flange part 14 Labyrinth seal formation part 14a, 25a Cylindrical part 14b Outer peripheral flange part 21 First lip seal member 24 Seal lip ( First seal lip)
24a, 33a, 34a Pressure receiving surface 24b Outer peripheral part 25, 35 Metal ring 25c Crimper end part 26 Rubber elastic body 26a Outer peripheral rubber part 26b Inner peripheral rubber part 26c Flange rubber part 31 Second lip seal member 33 Second seal lip 34 First Three seal lip 41 Labyrinth seal 51, 61 Pumping mechanism A Inside machine B Outside machine

Claims (6)

In the water pump sealing device (1) mounted between the housing (2) and the shaft (3) so that a sealing fluid such as LLC does not leak from the inside (A) to the outside (B),
A seal lip (24) fixed to the housing (2) and slidably in contact with a sleeve (11) fixed to the shaft (3); and the machine lip (A) of the seal lip (24) A water pump sealing device comprising a labyrinth seal (41) set by a sleeve (11). The sealing device for a water pump according to claim 1,
A sealing device for a water pump, wherein a second seal lip (33) is provided on the outside (B) of the seal lip (24). The water pump sealing device according to claim 2,
A metal ring (25) for fixing the seal lip (24) to the housing (2) is provided, and the second seal lip (33) is prevented from coming off at the axial end of the metal ring (25). The water pump sealing device is characterized in that a caulking end (25c) is integrally provided. In the sealing device for water pumps in any one of Claims 1 thru | or 3,
A sealing device for a water pump, characterized in that a pumping mechanism (51) that exhibits a return pumping action is provided on at least one of a pair of opposed surfaces in the axial direction constituting the labyrinth seal (41). In the sealing device for water pumps in any one of Claims 1 thru | or 4,
A sealing device for a water pump, wherein a pumping mechanism (61) that exhibits a return pumping action is provided on at least one of the sliding surfaces of a seal lip (24) and a sleeve (11) that slide relative to each other. In the sealing device for water pumps in any one of Claims 1 thru | or 4,
A sealing device for a water pump, characterized in that a foreign matter trapping mechanism is provided on at least one of the sliding surfaces of the seal lip (24) and the sleeve (11) that slide relative to each other and that captures the foreign matter that has been caught. .

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