JP7364500B2 - How to replace oil seal - Google Patents

Description

The present invention relates to a seal mechanism and an oil seal replacement method.

In devices such as motors, pumps, and reducers where a portion of the rotating shaft is exposed to the outside, the shaft seal is exposed to prevent oil such as lubricating oil for the rotating shaft from leaking outside from the exposed portion of the rotating shaft. It may be provided around the axis of the part.
A mechanical element called an oil seal is known as a specific component of the shaft seal. An oil seal has a structure in which a metal ring is embedded in an annular elastic body such as rubber, and is mounted around a rotating shaft and is pressed and fixed against a housing such as a housing. The housing is secured to the device so as to occlude the exposed portion.
Here, if the oil seal is a closed circular ring shaped like a closed curve, it is necessary to insert the oil seal from the end of the rotating shaft during installation. Therefore, if a device that transmits power via the rotating shaft is connected to both ends of the rotating shaft, an oil seal cannot be installed unless one device is removed from the rotating shaft, making the task of replacing the oil seal complicated. become.
Therefore, as a structure in which an oil seal can be attached without removing the equipment connected to the rotating shaft, a structure in which a part of the oil seal is cut to form a C-shape is also known (Patent Document 1).

Utility Model Publication No. 05-58895

However, in a structure where a part of the oil seal is cut off, oil may leak from the cut part. In Patent Document 1, in order to deal with oil leakage, oil seals with vertical lips that come into elastic contact in the axial direction of the rotating shaft are arranged in multiple stages. may be subject to restrictions.
The present invention has been made in view of the above problems, and aims to provide a seal mechanism that can suppress oil leakage regardless of the type or structure of the oil seal.

The present invention also provides a method for replacing an oil seal housed in a housing section that is an annular gap between the inner periphery of a housing provided around the axis of a rotating shaft and the outer periphery of the rotating shaft. has a first storage part formed on the front side and a second storage part formed on the back side in line with the axial direction of the rotating shaft, and the second storage part has a radial dimension. a removal step of pulling out and removing the closed curved oil seal, which is configured smaller than the first storage part and arranged in the first storage part, toward the front side in the axial direction of the rotating shaft; and a removal step of removing the oil seal for replacement . a step of arranging a seal around the axis of the rotating shaft and in front of the first storage section; an outer peripheral surface having an outer diameter larger than an inner diameter of the second storage section; and an outer peripheral surface directly connected to the outer peripheral surface of the rotating shaft A cover member having a sealing inner circumferential surface that is an opposing inner circumferential surface and has an inner diameter smaller than the inner diameter of the storage portion is abutted against the end surface of the replacement oil seal, and the second storage on the back side in the axial direction a pushing step of pushing and fixing the replacement oil seal into the first storage portion; and a cover member fixing step of fixing the cover member to the housing with a part of the cover member stored in the first storage portion. It is characterized by carrying out.

In the present invention, the sealing inner circumferential surface forms a mechanical seal between the cover member and the rotating shaft, and oil leaking from the oil seal is prevented from leaking to the outside by the sealing inner circumferential surface.
Therefore, oil leakage can be suppressed regardless of the type or structure of the oil seal.

FIG. 2 is a schematic plan view of a machine room of a crane in which a reducer with an output shaft to which a seal structure according to an embodiment of the present invention is applied is installed, in which the parts other than the reducer and devices connected to the reducer are lined with broken lines. Indicated by FIG. 2 is a diagram (partially sectional view) of the vicinity of region R in FIG. 1 viewed from the X direction, and the cross section is indicated by diagonal lines. FIG. 3 is an exploded perspective view showing the housing, oil seal, and cover member of FIG. 2, with bolts omitted. 3 is a diagram showing a procedure of an oil seal replacement method according to an embodiment of the present invention, and corresponds to a part of region R in FIG. 2. FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail based on the drawings.
First, the configuration of an apparatus provided with a shaft seal having a seal structure according to the present embodiment will be described with reference to FIGS. 1 to 3.
Here, as an example of a device provided with a shaft seal part, a reduction gear for a girder hoist installed in a machine room of a quay crane and winding up a wire for raising and lowering a movable girder will be exemplified.

A girder hoist 101 shown in FIG. 1 is a device that rotates a movable girder that rotates upward among the girders of a quay crane, and is located in a machine room 200, which is a building placed on the girder of the quay crane. will be placed in The girder hoist 101 includes a motor 105, a speed reducer 107, and a drum 109. The motor 105 is a motor that supplies driving force to rotate the movable girder. The reducer 107 is a device that adjusts the driving force transmitted from the motor 105 to a predetermined rotation speed and torque using a gear box (not shown) or the like, and is connected to the output shaft of the motor 105. The drum 109 is a rotating cylinder that rotates the movable girder by winding up a wire (not shown) bound to the movable girder, and is connected to a rotating shaft 111 that is the output shaft of the speed reducer 107 .

As shown in FIG. 2, the tip of the rotating shaft 111 is exposed through an opening 6a provided in the casing member 6, which is the exterior of the reducer 107. The rotating shaft 111 is held by a bearing 33 provided in the opening 6a. The opening 6a is closed by a shaft seal 300 provided around the rotating shaft 111.
The above is a description of the configuration of the device provided with the shaft seal portion 300.

Next, the configuration of the shaft seal portion 300 will be described with reference to FIGS. 1 to 3.
As shown in FIGS. 2 and 3, the shaft seal section 300 includes a housing 3, an oil seal 5, and a seal mechanism 100.
The housing 3 is a member that holds the oil seal 5, and includes a main body 3a and a flange 3b. The main body 3a is a cylindrical portion that holds the oil seal 5, and includes storage portions 17a, 17b and a housing communication hole 23. The storage portion 17a is an annular gap formed between the inner circumference of the main body 3a and the outer circumference of the rotating shaft 111. In FIG. 2, the housing portion 17a is a circumferential groove formed on the inner periphery of the housing 3, and the end face 17c of the rotating shaft 111 in the axial direction is open. Note that the end surface 17c is a cylindrical end surface of the main body 3a, and is a surface facing the outside of the casing member 6 (direction A1 in FIG. 2).

Like the storage portion 17a, the storage portion 17b is also an annular gap formed between the inner periphery of the main body 3a and the outer periphery of the rotating shaft 111. However, the accommodating part 17b is a circumferential groove arranged closer to the inside of the casing member 6 than the accommodating part 17a in the axial direction of the rotating shaft 111, and has a smaller radial dimension than the accommodating part 17a. The storage portion 17b is a portion into which the oil seal 5 is inserted, and the end surface opposite to the side that contacts the storage portion 17a in the axial direction of the rotating shaft 111 constitutes a bottom surface 19. The bottom surface 19 is a surface against which the oil seal 5 abuts, and its inner diameter is slightly larger than the outer diameter of the rotating shaft 111. However, the shapes of the storage portions 17a and 17b can be appropriately set depending on the dimensions of the oil seal 5 to be stored. For example, the outer diameters of the storage portion 17a and the storage portion 17b may be the same, or the storage portion 17a and the storage portion 17b may be integrated.

The oil seal 5 is a member that prevents oil such as lubricating oil from the rotating shaft 111 from leaking to the outside of the reducer 107, and has a structure in which a metal ring is embedded as necessary in an annular elastic body such as rubber. Be prepared. The oil seal 5 may be a closed circular ring with a closed curve, or may be C-shaped with a portion cut in the radial direction, as shown in FIG. Although the oil seal 5 is provided in the storage portion 17b in FIG. 2, it can also be provided in the storage portion 17a if it has a closed annular shape and the external dimensions match the external shape of the storage portion 17a.

The housing communication hole 23 is one of the flow paths for returning lubricating oil leaked from the oil seal 5 into the inside of the reducer 107. As shown in FIG. 2, the housing communication hole 23 is a communication hole that communicates between an inner end surface 29 of the main body 3a, which is an end surface opposite to the end surface 17c, and a circumferential surface 25 of the storage portion 17a.
The flange 3b is a member for fixing the housing 3 to the casing member 6, and is an annular collar provided around the outer periphery of the housing 3 near the inner end surface 29. The flange 3b includes a hole 14 (see FIG. 3) through which the bolt 8 is inserted in the thickness direction of the ring. In this structure, the housing 3 is fixed to the casing member 6 by inserting the bolt 8 into the hole 14 and screwing the bolt 8 into a not-illustrated screw hole provided in the casing member 6.

Note that when replacing the oil seal 5, it is necessary to move the oil seal 5 in the axial direction of the rotating shaft 111 and remove it from the storage portion 17b, as shown in the direction A1 in FIG. On the other hand, as shown in FIG. 2, one end of the rotating shaft 111 is held by the bearing 33 of the reducer 107, and the other end is fixed to the input shaft of the drum 109, as shown in FIG. Therefore, if it is necessary to move the oil seal 5 in the axial direction of the rotating shaft 111 for reasons such as replacing the oil seal 5 in the state shown in FIG. be. When moving the oil seal 5 in the axial direction of the rotating shaft 111 beyond this range, it is necessary to remove the drum 109 from the rotating shaft 111.

The seal mechanism 100 is a member that fixes the oil seal 5 to the housing 3 and also functions as a seal, and has a cover member 1 as shown in FIG. 2.
The cover member 1 is a member that fixes the oil seal 5 in the accommodating portion 17b of the housing 3 by pushing the oil seal 5 in the axial direction of the rotating shaft 111 and toward the inside of the casing member 6 (direction A2 in FIG. 2). The cover member 1 has a cover body 9, an inner peripheral surface 7 for sealing, a groove 15, a discharge hole 21, and a flange 11, as shown in FIG.
The cover body 9 is a cylindrical member that comes into contact with the oil seal 5. The cover main body 9 is also a member that faces the outer peripheral surface of the rotating shaft 111. In FIG. 2, the cover main body 9 has an outer peripheral shape corresponding to the storage portion 17a, and a portion thereof is stored in the storage portion 17a. The cover main body 9 has an inner peripheral shape corresponding to the outer peripheral surface of the rotating shaft 111, and at least a part of the inner peripheral surface is the inner peripheral surface 7 for sealing.

The sealing inner circumferential surface 7 is a sealing surface that prevents oil from leaking from the cover member 1 to the outside. The sealing inner circumferential surface 7 is an inner circumferential surface that directly faces the outer circumferential surface of the rotating shaft 111 and has an inner diameter that is slightly larger than the outer diameter of the rotating shaft 111. Directly opposing here means that the sealing inner circumferential surface 7 and the outer circumferential surface of the rotating shaft 111 are opposed to each other without intervening another sealing member such as the oil seal 5, Including when facing each other.

In this configuration, when the rotating shaft 111 rotates, the sealing inner peripheral surface 7 becomes a sliding surface with respect to the rotating shaft 111. Therefore, even if the lubricating oil leaks from the oil seal 5 in the direction A1 in FIG. 2, the sealing inner circumferential surface 7 acts as a mechanical seal, and the lubricating oil can be prevented from leaking to the outside of the cover member 1.
Moreover, since the sealing inner circumferential surface 7 is a member provided on the cover member 1 instead of the oil seal 5, it functions as a mechanical seal regardless of the structure of the oil seal 5. In particular, even if the oil seal 5 is C-shaped and does not have a sufficient function to prevent lubricating oil from leaking from the cut portion 5a shown in FIG. Acts as. Therefore, the cover member 1 can suppress leakage of lubricating oil regardless of the type or structure of the oil seal 5.
Further, the cover member 1 is also a member for pushing the oil seal 5 and fixing it to the housing 3. Therefore, when fixing the oil seal 5 to the housing 3, it is advantageous in that a separate pushing jig is not required.

The groove portion 15 has a structure for retaining a certain amount of lubricating oil leaking from the oil seal 5 in the direction A1 in FIG. 2, and is a circumferential groove provided in the seal inner peripheral surface 7 of the cover body 9.
By providing the groove 15, lubricating oil leaking from the oil seal 5 in the direction A1 in FIG. acts as a lubricant. Therefore, the lubricity when the seal inner peripheral surface 7 slides can be improved.
Further, since a portion of the lubricating oil leaking from the oil seal 5 flows into the groove 15 and is retained therein, the possibility that the lubricating oil retained in the groove 15 leaks to the outside of the cover member 1 is extremely low. Therefore, the effect of preventing the lubricating oil from leaking to the outside of the cover member 1 by the sealing inner circumferential surface 7 is further improved.
Note that the width and depth of the groove portion 15 may be appropriately set within a range in which the inner circumferential surface 7 for sealing functions as a mechanical seal, and in consideration of the amount of lubricating oil that is expected to leak from the oil seal 5.

The discharge hole 21 is one of the flow paths for returning lubricating oil leaked from the oil seal 5 into the inside of the reducer 107.
The discharge hole 21 is a flow path that communicates the housing communication hole 23 and the groove portion 15. More specifically, the discharge hole 21 is a flow path that communicates the outer peripheral surface of the cover body 9 that is in contact with the housing communication hole 23 with the groove portion 15 .
In this structure, the lubricating oil accumulated in the groove 15 is discharged from the inner end surface 29 via the discharge hole 21 and the housing communication hole 23. The inner end surface 29 is located on the opposite side of the cover member 1 with the oil seal 5 in between in the axial direction of the rotating shaft 111, and thus faces the inside of the speed reducer 107. Therefore, by providing the discharge hole 21, the lubricating oil accumulated in the groove 15 can be returned to the inside of the reducer 107 via the housing communication hole 23, which is more advantageous in suppressing lubricating oil leakage. .

As shown in FIG. 2, the discharge hole 21 and the housing communication hole 23 are preferably provided vertically downward in the housing 3 and the cover member 1 as much as possible. This is because by providing these structures vertically downward, the lubricating oil accumulated in the groove portion 15 is discharged from the inner end surface 29 via the discharge hole 21 and the housing communication hole 23 under its own weight.

In FIG. 3, the cover main body 9 is two semi-cylindrical divided members 9a and 9b equally divided in the circumferential direction of the cylinder. With this structure, the cover body 9 can be removed from the rotating shaft 111 by moving it in the radial direction of the rotating shaft 111 without removing the drum 109 from the rotating shaft 111 shown in FIG.
The cover main body 9 may have a structure divided into a plurality of parts in the circumferential direction of a cylinder, and the number of divisions of the cover body 9 may be three or more, as long as it can be removed from the rotating shaft 111 by moving in the radial direction of the rotating shaft 111. In this case, there is no need for equal division. Further, the cover body 9 does not necessarily need to be removed from the rotating shaft 111 as long as it can be separated from the housing 3 when replacing the oil seal 5. Therefore, the cover main body 9 may be a single cylindrical member instead of having a divided structure.

In addition, when the cover body 9 is divided into a plurality of parts and the oil seal 5 is also divided into a C-shape or the like, the divided surface of the cover body 9 as seen from the axial direction of the rotating shaft 111 is shown in FIG. It is preferable that the dividing surfaces of the oil seal 5 and the oil seal 5 do not overlap.
With this arrangement, even if the lubricating oil leaks from the divided surface of the oil seal 5, it is possible to prevent the leaked lubricating oil from further leaking from the divided surface of the cover body 9.

The flange 11 is a member for fixing the cover member 1 to the housing 3. As shown in FIG. 2, the flange 11 is provided around the outer periphery of the cover body 9 near the non-contact surface 9d, which is the surface opposite to the contact surface 9c that contacts the oil seal 5 of the cover body 9 in the axial direction of the rotating shaft 111. It is a circular tsuba. As shown in FIG. 3, the flange 11 includes a hole 4 through which a bolt 13 is inserted in the thickness direction of the ring. In this structure, the bolt 13 shown in FIG. 2 is inserted into the hole 4 shown in FIG. is fixed to the housing 3.
Further, in this structure, when the cover member 1 is fixed to the housing 3 with the bolts 13, the contact surface 9c of the cover member 1 shown in FIG. 2 uniformly presses the oil seal 5 against the housing portion 17b. Therefore, there is no need to separately prepare a jig for pressing the oil seal 5 uniformly.
The above is an explanation of the configuration of the shaft seal portion 300.

Next, a method for replacing the oil seal 5 stored in the storage portion 17a will be explained with reference to FIGS. 2 to 4.
First, as shown in FIG. 4A, it is assumed that the existing oil seal 5b having a closed curve shape is accommodated in the storage portion 17a, and the cover member 1 is not attached to the housing 3.
Suppose that the existing oil seal 5b needs to be replaced with a new one because it has reached its useful life or is worn out.

In this case, first, the existing oil seal 5b is pulled in the direction of A1 in FIG. 4(a) and taken out from the storage portion 17a. Further, the existing oil seal 5b is cut and moved in the radial direction of the rotating shaft 111 to be removed from the rotating shaft 111 (removal step).

Next, as shown in FIG. 4(b), the replacement oil seal 5c is placed in front of the storage portion 17a around the rotating shaft 111 (placement step). Here, the front side of the storage portion 17a means a position opposite to the casing member 6 with the housing 3 in between in the axial direction of the rotating shaft 111. Moreover, it is preferable that the replacement oil seal 5c is a C-shaped oil seal. In the case of a C-shaped oil seal, it can be placed around the rotating shaft 111 by opening the cut portion 5a of the replacement oil seal 5c and pushing it in the radial direction of the rotating shaft 111. This is because there is no need to remove the rotary shaft 109 from the rotating shaft 111.

When the replacement oil seal 5c is C-shaped, it is preferable to arrange it so that the cut portion 5a is positioned furthest upward in the vertical direction, as shown in FIG. This is because the lower the position of the cutting part 5a is, the more easily the lubricating oil that has moved downward due to gravity leaks from the cutting part 5a.
Furthermore, as shown in FIG. 4(b), the cover member 1 is arranged around the rotating shaft 111 in front of the replacement oil seal 5c. Here, the front side of the replacement oil seal 5c means a position opposite to the housing 3 with the replacement oil seal 5c in between in the axial direction of the rotating shaft 111. If the cover member 1 has a structure in which it is divided into a plurality of parts, it is preferable to arrange the parts so that the divided surfaces are located as vertically upward as possible. For example, in FIG. 3, since the cover main body 9 is divided into semi-cylindrical divided members 9a and 9b, the arrangement is such that both of the two divided surfaces are located as vertically upward as possible, so that the axial direction of the rotating shaft 111 is Set the position so that the imaginary line L connecting the two divided planes is horizontal when viewed from above.
Since lubricating oil tends to accumulate downward due to its own weight, by arranging the dividing surface as vertically upward as possible, the possibility that the lubricating oil leaking from the oil seal 5 will leak from the dividing surface is reduced.

Next, the cover member 1 is moved in the direction A2 in FIG. 4(b), the contact surface 9c is brought into contact with the end face of the replacement oil seal 5c, and the replacement oil seal 5c is pushed in the axial direction of the rotating shaft 111. It is fixed in the storage portion 17b (seal pushing step). The pushing depth of the cover member 1 in the A2 direction is appropriately set within a range that allows the cover member 1 to apply the necessary pressing force to fix the replacement oil seal 5c to the housing portion 17b. Specifically, the replacement oil seal 5c may be pushed to a position just before the flange 11 butts against the housing 3.

Finally, as shown in FIG. 4(c), the cover member 1 is fixed to the housing 3 with bolts 13 (cover member fixing step). At this time, since the contact surface 9c of the cover member 1 uniformly presses the replacement oil seal 5c, there is no need to separately prepare a jig for uniformly pressing the replacement oil seal 5c.
In this way, when replacing the oil seal 5, the cover member 1 is used for two purposes: configuring a mechanical seal and as a jig for replacing the oil seal.
Note that the procedure is the same when replacing the replacement oil seal 5c with a new one. Specifically, first, the cover member 1 is removed from the housing 3, and the replacement oil seal 5c is taken out from the storage portion 17a (removal step). Next, the replacement oil seal 5c is placed in front of the storage portion 17a around the rotating shaft 111 (placement step). Next, a new replacement oil seal 5c is pushed into the housing portion 17b using the cover member 1 (seal pushing step). Finally, the cover member 1 is fixed to the housing 3 with bolts 13 (cover member fixing step).
The above is an explanation of the method for replacing the oil seal 5 stored in the storage portion 17a.

In this embodiment, the cover member 1 that presses and fixes the oil seal 5 into the housing 3 has the sealing inner circumferential surface 7 that directly faces the outer circumferential surface of the rotating shaft 111, and the cover member 1 and the rotating shaft Between 111 and 111, the sealing inner circumferential surface 7 becomes a mechanical seal.
Therefore, oil leakage can be suppressed regardless of the type or structure of the oil seal 5.
Furthermore, since the cover member 1 of this embodiment is also a member that uniformly pushes and fixes the oil seal 5 into the housing 3, a separate jig for pushing is not required when fixing the oil seal 5 to the housing 3. Furthermore, since a separate jig for pushing is not required, there is no need to secure a space for attaching a jig for pushing when replacing the oil seal 5. Therefore, there is no need to remove the drum 109 connected to the axial end of the rotating shaft 111 when replacing the oil seal 5, and the workability is also excellent.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the embodiments.
For example, in the above-described embodiment, the rotating shaft 111 of the reducer 107 for a girder of a crane is exemplified as the object on which the cover member 1 is provided, but the object on which the cover member 1 is provided is to remove oil from the rotating shaft using an oil seal. Applicable to any structure to prevent leakage. For example, the target may be the output shaft of a reducer of a hoisting machine that hoists a hanging device of a crane, or an output shaft other than the reducer may be targeted. Alternatively, the output shaft of a device other than a crane may be targeted.

1 Cover member 3 Housing 3a Main body 3b Flange 4 Hole 5 Oil seal 5a Cutting portion 5b Existing oil seal 5c Replacement oil seal 6 Casing member 6a Opening 7 Inner peripheral surface for seal 8 Bolt 9 Cover main body 9a, 9b Divided member 9c Contact surface 9d Non-contact surface 10 Bolt screw hole 11 Flange 13 Bolt 14 Hole 15 Groove 17a, 17b Storage section 17c End surface 19 Bottom surface 21 Discharge hole 23 Housing communication hole 25 Circumferential surface 29 Inner end surface 33 Bearing 100 Seal structure 101 For girder Hoist 105 Motor 107 Reducer 109 Drum 111 Rotating shaft 200 Machine room 300 Shaft seal

Claims (2)

A method for replacing an oil seal housed in a housing section that is an annular gap between an inner periphery of a housing provided around a rotating shaft and an outer periphery of the rotating shaft, the method comprising:
The storage section has a first storage section formed on the front side and a second storage section formed on the back side, which are arranged in the axial direction of the rotating shaft, and the second storage section is arranged in the axial direction of the rotating shaft. is configured to have smaller dimensions than the first storage section,
a removal step of pulling out the closed curved oil seal disposed in the first storage portion toward the front side in the axial direction of the rotating shaft, and removing it;
a step of arranging a replacement oil seal around the rotating shaft and in front of the first storage portion;
an outer circumferential surface having an outer diameter larger than the inner diameter of the second storage section; and an inner circumferential surface for a seal that directly faces the outer circumferential surface of the rotating shaft and has an inner diameter smaller than the inner diameter of the storage section. a pushing step of abutting a cover member having the replacement oil seal against an end face of the replacement oil seal, and pushing and fixing the replacement oil seal into the second storage portion on the back side in the axial direction;
a cover member fixing step of fixing the cover member to the housing with a part of the cover member stored in the first storage part;
An oil seal replacement method characterized by carrying out the following. The cover member has two semi-cylindrical divided members obtained by equally dividing a cylinder in the circumferential direction, and the replacement oil seal is configured in a C-shape having a cut portion,
The replacement oil seal is placed in the second storage part with the cutting part located at the highest point in the vertical direction, and when viewed in the axial direction of the rotating shaft, the two dividing surfaces of the cover member are visible. 2. The oil seal replacement method according to claim 1, wherein the cover member is fixed to the housing in a state where the connecting imaginary lines are horizontal.

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