JP6181473B2 - Sealing device - Google Patents

Description

  The present invention relates to a sealing device used for sealing an output shaft portion of, for example, an automobile transfer device.

  For example, in a transfer device of an automobile, muddy water or water is contained in a case between a case housing a drive mechanism and an output shaft (rotary shaft) that projects from a housing formed in the case and outputs a driving force. A sealing device is provided for preventing dust from entering and preventing the lubricating oil in the case from leaking to the atmosphere side.

As shown in FIG. 5, the sealing device is configured by combining a first seal member 102 provided on the housing 101 and a second seal member 104 provided on a rotary shaft 103 that can rotate around a horizontal axis. ing.
The first seal member 102 includes a first metal ring 105 that is fixed to the housing 101, and a seal lip 106 that is provided on the first metal ring 105 and that is in sliding contact with the outer peripheral surface of the rotating shaft 103.

  The second seal member 104 has a second metal ring 107 fitted and fixed to the rotating shaft 103, and an annular dust strip 108 and a side lip 109 provided on the second metal ring 107, Both the lips 108 and 109 are in sliding contact with the first metal ring 105 of the first seal member 102, thereby sealing the annular space between the housing 101 and the rotating shaft 103. The dust lip 108 is disposed radially outward of the side lip 109 and mainly prevents muddy water from entering the housing 101. The side lip 109 mainly prevents muddy water that has passed through the dust lip 108 from entering the housing 101 (see, for example, Patent Document 1).

JP 2006-17212 A

In the sealing device, when the rotary shaft 103 is rotated at a low speed, the atmospheric mud may enter between the dust lip 108 and the side lip 109 in some cases. The infiltrated muddy water is rotated around the dust lip 108 due to the centrifugal force associated with the rotation of the rotating shaft 103. However, when the rotation of the rotating shaft 103 is stopped, the infiltrated muddy water is surrounded by the gravity. Or along the peripheral surface of the first metal ring, as shown by the cross-hatched portion in FIG. 5, the first metal ring 105 is deposited on the lower side, and the accumulated muddy water infiltrates radially inward of the side lip 109. There was a problem to do.
This invention is made in view of such a problem, and when the rotation of a rotating shaft is stopped, the sealing device which can suppress that muddy water penetrate | invades into the radial inside of a side lip. The purpose is to provide.

  The seal member of the present invention includes a first seal member provided in the housing, and a second seal member provided so as to be integrally rotatable around a horizontal axis with respect to a rotation shaft having an outer diameter of 40 mm or more and 45 mm or less, The first seal member includes a first metal ring fixed to the housing, and a seal lip provided on the first metal ring and in sliding contact with an outer peripheral surface of the rotation shaft, and the second seal member includes: A second metal ring fixed to the rotating shaft; a side lip provided on the second metal ring and slidably contacting the first metal ring; and slidably contacting the first metal ring radially outward of the side lip. A sealing device having a dust lip, wherein a radial separation distance between a sliding contact portion of the side lip with the first metal ring and a sliding contact portion of the dust lip with the first metal ring is 2 Characterized in that it is set to 5mm or more and 5.0mm or less.

  According to the present invention, the sliding contact portion of the dust lip can be separated radially outward with respect to the sliding contact portion of the side lip, so that it enters between the dust lip and the side lip during the rotation of the rotating shaft. Even if the muddy water is accumulated under the first metal ring by gravity when the rotation of the rotating shaft is stopped, the accumulated muddy water is prevented from entering inward in the radial direction of the side lip. Can do.

  According to the present invention, when the rotation of the rotating shaft is stopped, the muddy water can be prevented from entering inward in the radial direction of the side lip.

It is sectional drawing which shows the transfer apparatus for motor vehicles using the sealing device which concerns on one Embodiment of this invention. It is an expanded sectional view showing the important section of the above-mentioned sealing device. It is a graph which shows the mud-water resistance test result of the said sealing device. It is sectional drawing which shows the state which muddy water accumulated on the lower side of the said sealing device. It is sectional drawing which shows the conventional sealing device.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view showing an automobile transfer device using a sealing device according to an embodiment of the present invention. As shown in FIG. 1, the transfer device 1 is a device for distributing the driving force of an engine (not shown) to the rear wheel side and the front wheel side. The transfer device 1 includes a main shaft 2 having one end 2a connected to the engine side and the other end 2b connected to a rear wheel differential device (not shown), and a main shaft 2 via a power transmission chain 3. And an output shaft 4 connected to a front wheel differential device (not shown), and a transfer case 5 for housing them.

The main shaft 2 includes a sprocket 2c around which the power transmission chain 3 is wound, connection means 2d for connecting the sprocket 2c to the main shaft 2 in an intermittent manner.
A predetermined amount of lubricating oil for lubricating each part accommodated in the transfer case 5 is stored in the transfer case 5. The transfer device 1 of the present embodiment uses a lubricating oil having a relatively low viscosity (for example, SAE viscosity number 75W-90).

  The transfer device 1 transmits the driving force of the engine input from one end 2a of the main shaft 2 to the rear wheel side differential device connected to the other end 2b. For the front wheel side differential device, the sprocket 2c is connected to the main shaft 2 by the connecting means 2d so that the driving force input to the main shaft 2 is applied to the output shaft 4 via the power transmission chain 3. Distribute. As a result, the transfer device 1 distributes the driving force of the engine to both the front-wheel differential device connected to the output shaft 4 and the rear-wheel differential device connected to the other end 2 b of the main shaft 2.

  Further, the transfer device 1 is disposed on the lower side of the vehicle body of the automobile on which the transfer device 1 is mounted. The main shaft 2 and the output shaft 4 of the transfer device 1 are arranged in parallel. Among these, since the both ends of the main shaft 2 are connected to the engine side and the rear wheel side, the transfer device 1 is disposed between the engine and the rear wheel side differential device. For this reason, the output shaft 4 is arranged offset further to the vehicle body lower side than the main shaft 2. Accordingly, the transfer device 1 is disposed on the vehicle body such that the output shaft 4 side protrudes downward from the vehicle body.

  The output shaft 4 includes a main body portion 4a on which a sprocket 6 around which the power transmission chain 3 is wound is provided, and a flange member 4b fixed to one end of the main body portion 4a. The output shaft 4 is provided in the transfer case 5. The bearing 8 is supported so as to be rotatable about a horizontal axis X. Further, the output shaft 4 is arranged so that the flange member 4b protrudes from the housing 7 formed in the transfer case 5 and communicating between the inside and outside of the case. The outer diameter D of the main body 4a of the output shaft 4 is set to 40 mm or more and 45 mm or less. The outer diameter D of this embodiment is set to 41 mm.

  As described above, since the lubricating oil is stored in the transfer case 5, the lubricating oil is prevented from leaking to the outside of the case (atmosphere side), and at the same time, muddy water and dust on the atmosphere side enter the case. In order to prevent this, a sealing device 10 that seals the annular space between the output shaft 4 and the housing 7 is provided in the annular space formed between the output shaft 4 and the housing 7 as a rotating shaft. ing.

  FIG. 2 is an enlarged cross-sectional view of FIG. In FIG. 2, the sealing device 10 includes a first seal member 20 fixed to the end of the housing 7, and a second seal member 30 fixed to the output shaft 4 that rotates relative to the housing 7 so as to be integrally rotatable. It is configured by combining.

The first seal member 20 includes a first metal ring 21 fixed to the housing 7 and a first seal body 22 provided on the first metal ring 21. The first metal ring 21 includes a first cylindrical portion 21a that is fitted and fixed to the inner peripheral surface 7a of the housing 7, and an annular fixed portion 21b that extends radially inward from one end portion of the first cylindrical portion 21a. Have. Further, the first metal ring 21 extends from the other end portion of the first cylindrical portion 21a to the outer side in the radial direction and comes into contact with the end surface 7b of the housing 7, and from the outer peripheral end portion of the annular portion 21c. A second cylindrical portion 21d extending outward in the axial direction and an annular portion 21e extending radially outward from the axial end of the second cylindrical portion 21d are provided.
In the present specification, the direction toward the outer side of the case when viewed from the transfer case 5 in the axial direction is also referred to as axially outward, and the direction toward the inner side of the case is also referred to as axially inward.

  The first metal ring 21 and the housing 7 are in close contact with each other by fitting and fixing the first cylindrical portion 21a to the inner peripheral surface 7a and have a sealing property. The first metal ring 21 is an annular member formed by pressing a stainless steel plate such as SUS304 or SUS430. For this reason, compared with cold-rolled steel sheets such as SPCC, for example, it has excellent corrosion resistance and high hardness as a material. Therefore, even if each lip described later comes into sliding contact, the first metal ring 21 itself wears early. The sealing performance will not be reduced.

  The first seal body 22 is formed using synthetic rubber, and is vulcanized and bonded to the fixing portion 21 b of the first metal ring 21. The first seal body 22 has a base portion 22a along the inner side surface of the fixed portion 21b. The base portion 22a includes an annular main lip (seal lip) 22b extending inward in the axial direction from the distal end side of the fixed portion 21b and slidably contacting the outer peripheral surface 4c of the main body portion 4a of the output shaft 4, and the distal end of the fixed portion 21b. An annular auxiliary lip 22c that extends obliquely outward in the axial direction from the side and forms a gap with the outer peripheral surface 4c of the output shaft 4, and extends outward in the axial direction (on the second seal member 30 side) from the fixed portion 21b. An annular protrusion 22d is formed.

  A circumferential groove 22b1 is formed on the outer circumferential surface of the main lip 22b, and an annular spring member 23 that presses the main lip 22b from the outer circumferential side is attached to the circumferential groove 22b1. The main lip 22 b is pressed against the outer peripheral surface 4 c of the output shaft 4 by being pressed by the spring member 23, and seals between the outer peripheral surface 4 c and the first metal ring 21.

  Moreover, since the main lip 22b is in sliding contact with the outer peripheral surface 4c of the output shaft 4 at a relatively high speed, the main lip 22b may be deteriorated by heat generated by the friction. Further, since the lubricating oil used in the transfer device 1 has a relatively low viscosity, there is a risk that the lubricating oil may easily leak from the lip when the eccentricity following property of the lip is lowered at a low temperature. Considering the above points, the first seal body 22 is preferably formed using acrylic rubber. This is because by using acrylic rubber, the heat resistance of each lip can be increased, and the eccentricity following property at a low temperature can be increased.

  The annular protrusion 22d of the first seal body 22 is formed such that the tip 22d1 forms a slight gap between an inner peripheral surface 32c1 of a protrusion 32c described later and a radially inner side wall 32c2. The labyrinth seal is constituted by the annular protrusion 22d and the protrusion 32c.

  A close contact portion 22e formed along the inner peripheral surface 7a of the housing 7 and in close contact with the inner peripheral surface 7a is formed on the outer peripheral side of the base portion 22a of the first seal body 22. Even if the close contact portion 22e is in close contact with the inner peripheral surface 7a and the sealing performance due to the fitting between the inner peripheral surface 7a and the first cylindrical portion 21a of the first metal ring 21 is reduced, It is possible to prevent the muddy water from entering the casing and the lubricating oil inside the case from leaking to the atmosphere side.

  The second seal member 30 has a second metal ring 31 fixed to the output shaft 4 and a second seal body 32 provided on the second metal ring 31. The second metal ring 31 is an annular member formed by pressing a cold rolled steel sheet. The second metal ring 31 includes a cylindrical portion 31a that is externally fitted and fixed to the outer peripheral surface of the flange member 4b of the output shaft 4, and an annular ring of the first metal ring 21 that extends radially outward from the cylindrical portion 31a. An annular main body 31b disposed opposite to the portion 21c, and an outer covering that extends from the outer peripheral end of the main body 31b toward the first metal ring 21 and covers the outer peripheral side of the second cylindrical portion 21d of the first metal ring 21 Part 31c.

  The outer covering portion 31c of the second metal ring 31 covers the outer peripheral side of the second cylindrical portion 21d with a slight gap between the outer peripheral end portion of the annular portion 21e of the first metal ring 21. Thereby, the outer cover part 31c comprises the labyrinth seal between the annular parts 21e.

  The second metal ring 31 and the output shaft 4 are in close contact with each other by fixing the cylindrical portion 31a to the outer peripheral surface of the flange member 4b, and have a sealing property. The second metal ring 31 is formed using a cold-rolled steel plate such as SPCC having relatively good workability, but a stainless steel plate having high corrosion resistance such as SUS304 or SUS430 can also be used in the same manner as the first metal ring 21. .

  The second seal body 32 is a member formed using synthetic rubber (for example, acrylonitrile-butadiene rubber (NBR), hydrogenated nitrile rubber (H-NBR)), and is attached to the body portion 31 b of the second metal ring 31. It is vulcanized and bonded. The second seal main body 32 has a thick base portion 32a along the inner surface of the main body portion 31b and the outer peripheral surface of the cylindrical portion 31a. The base portion 32a includes an annular dust strip 32b that extends obliquely outward in the radial direction axially inward from the outer peripheral end portion thereof and slidably contacts the inner peripheral surface of the second cylindrical portion 21d of the first metal ring 21, and a base portion A projecting portion 32c projecting annularly inward in the axial direction from the side surface of 32a, and an annular portion 21c of the first metal ring 21 extending radially outward from the tip end portion of the projecting portion 32c inward in the axial direction. An annular side lip 32d slidably contacting the outer surface is formed. Thereby, the dust lip 32 b and the side lip 32 d seal the space between the first metal ring 21 and the second metal ring 31.

  The dust lip 32b extends from the outer peripheral end of the base portion 32a radially inward in the axial direction and is folded back so that the tip end faces outward in the axial direction. The metal ring 21 is in sliding contact with the inner peripheral surface of the second cylindrical portion 21d. Thus, by forming the dust lip 32b in a C-shaped cross section, even if the eccentric amount of the output shaft 4 with respect to the housing 7 becomes excessive, the reaction force against the output shaft 4 by the dust lip 32b can be kept low. An increase in the rotational resistance of the sealing device 10 can be suppressed, and the dust lip 32b can be prevented from being excessively worn.

  The dust lip 32b is arranged farther outward in the radial direction than the side lip 32d. Specifically, the radial direction of the sliding contact portion of the side lip 32d with the annular portion 21c of the first metal ring 21 and the sliding contact portion of the first metal ring 21 with the second cylindrical portion 21d of the dust lip 32b. Is set to 2.5 mm or more and 5.0 mm or less. The separation distance L in this embodiment is set to 5.0 mm.

  The separation distance L is set to 2.5 mm or more and 5.0 mm or less if the distance L is less than 2.5 mm, and the effect of preventing muddy water from entering inward in the radial direction of the side lip 32d. This is because the outer peripheral end of the outer cover portion 31c of the second metal ring 31 may come into contact with the transfer case 5 which is another member when the thickness exceeds 5.0 mm.

Next, in order to verify the effect of the sealing device 10 according to the above embodiment, the result of a verification test performed by the present inventors will be described.
As the sealing device used for this test, the state where the first seal member 20 was removed in the sealing device shown in FIG. 2, that is, the state where only the second seal member 30 was used was used as an example product, and as a comparative example product, The conventional sealing device shown in FIG. 5 was used.

  As a test method, mud mixed with water and test dust (JIS standard product) at a predetermined mixing ratio is stored in a mud tank, and the rotating shaft (output shaft 4) is driven at low speed (rotation speed = 560 rpm). Then, the time until the muddy water enters the radial direction inward of the side lip 32d of the sealing device 10 is measured as the muddy water sealing time, and the muddy water sealing time is compared between the example product and the comparative example product. Sexuality was evaluated.

  FIG. 3 is a graph showing the mud water resistance test results. In the figure, the muddy water infiltrated in 72 hours in the comparative product, whereas the muddy water did not infiltrate even in 680 hours in the example product. From this result, it can be seen that the muddy water resistance of the example products is dramatically improved.

  As described above, according to the sealing device 10 of the present embodiment, the radial separation distance between the sliding contact portion with the first metal ring 21 in the side lip 32d and the sliding contact portion with the first metal ring 21 in the dust lip 32b. Since L is set to 2.5 mm or more and 5.0 mm or less, the second seal member 30 does not interfere with the transfer case 5 which is another member, and the sliding contact portion of the dust lip 32b is slid on the side lip 32d. The contact portion can be separated radially outward.

  As a result, when the output shaft 4 rotates, the muddy water that has entered between the dust lip 32b and the side lip 32d travels along the circumferential surface of the dust lip 32b by gravity when the output shaft 4 stops rotating. As shown by the cross-hatched portion in FIG. 4, the first metal ring 21 is deposited below the sliding contact portion with the side lip 32d. Therefore, even if muddy water accumulates under the first metal ring 21 due to gravity when the rotation of the output shaft 4 is stopped, the accumulated muddy water is prevented from entering inward in the radial direction of the side lip 32d. can do.

  The present invention is not limited to the above embodiments. The sealing device 10 of the above embodiment is exemplified as a seal between the output shaft 4 and the housing 7 of the transfer device 1, but is applied to a device that seals between the both end sides of the main shaft 2 and the transfer case 5. It can also be applied, and it can also be applied to a device that seals between the differential shaft and the input shaft or output shaft of the differential device.

  4: output shaft (rotating shaft), 7: housing, 10: sealing device, 21: first metal ring, 22: first seal member, 22b: main lip (seal lip), 30: second seal member, 31: Second metal ring, 32b: Dustrip, 32d: Side lip, D: Outer diameter, L: Separation distance, X: Horizontal axis

Claims (1)

A first seal member provided in the housing, and a second seal member provided so as to be integrally rotatable around a horizontal axis with respect to a rotation shaft having an outer diameter of 40 mm or more and 45 mm or less,
The first seal member has a first metal ring fixed to the housing, and a seal lip provided on the first metal ring and in sliding contact with the outer peripheral surface of the rotation shaft,
The second seal member includes a second metal ring fixed to the rotation shaft, a side lip provided on the second metal ring and in sliding contact with the first metal ring, and radially outward of the side lip. A sealing device having a dust strip in sliding contact with the first metal ring,
A radial separation distance between a sliding contact portion with the first metal ring in the side lip and a sliding contact portion with the first metal ring in the dust lip is set to 2.5 mm or more and 5.0 mm or less. The sealing device characterized by being made.

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