JP2013170561A - Sealing device of transmission case of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device of a transmission case of an engine capable of suppressing the abrasion of lips on an inner peripheral side of an oil seal, and a collar.SOLUTION: In a sealing device of a transmission case of an engine, an inside transmission wheel 4 is fitted to an outer periphery of a rotary transmission shaft 2 in the transmission case 1, a transmission shaft inserting hole 5 is formed in a case wall 3 of the transmission case 1, an outside transmission wheel 7 is fitted to an outer periphery of a projecting part 6 of the rotary transmission shaft 2 outside the transmission case 1, a lip abutment face 2a is formed at an outer peripheral side of the rotary transmission shaft 2 in the transmission shaft inserting hole 5, an oil seal 9 is fitted to an inner periphery of the transmission shaft inserting hole 5, and lips 9a, 9b on an inner peripheral side of the oil seal 9 abut on the lip abutment face 2a on the outer peripheral side of the rotary transmission shaft 2. The oil seal 9 is covered with the outside transmission wheel 7 from a front side, a front lip 9c is formed at the oil seal 9, and the front lip 9c is made to abut on a rear face 7a of the outside transmission wheel 7.

Description

  The present invention relates to an engine transmission case sealing device, and more particularly, to an engine transmission case sealing device capable of suppressing wear of a lip portion and a lip portion contact surface on the inner peripheral side of an oil seal.

Conventionally, as a sealing device for an engine transmission case, a rotation transmission shaft is inserted into the transmission case, an internal transmission wheel is fitted around the outer periphery of the rotation transmission shaft in the transmission case, and a transmission shaft insertion hole is formed in the case wall of the transmission case. The rotation transmission shaft is projected outside the transmission case through the transmission shaft insertion hole, the outer transmission wheel is fitted on the outer periphery of the projection of the rotation transmission shaft outside the transmission case, and the outer peripheral side of the rotation transmission shaft in the transmission shaft insertion hole Lip part abutting surface is provided, an oil seal is fitted on the inner periphery of the transmission shaft insertion hole, and the lip part on the inner peripheral side of the oil seal is in contact with the lip part abutting surface on the outer peripheral side of the rotary transmission shaft (For example, refer to Patent Document 1).
According to this type of sealing device, there is an advantage that oil in the transmission case can be prevented from leaking out of the transmission case through the transmission shaft insertion hole by the lip portion on the inner peripheral side of the oil seal.
However, this conventional sealing device has a problem because there is no means for preventing dust and muddy water from approaching the lip portion on the inner peripheral side of the oil seal and the contact surface of the lip portion.

Japanese Utility Model Publication No. 6-22552 (refer to FIG. 1)

<Problem> The lip portion on the inner peripheral side of the oil seal and the lip contact surface are easily worn.
Since there is no means to prevent dust and muddy water from approaching the lip part on the inner circumference side of the oil seal and the lip part contact surface, the lip part on the inner circumference side of the oil seal is caught by foreign matter such as dust and mud. And the lip contact surface are subject to wear.

  The subject of this invention is providing the sealing device of the transmission case of an engine which can suppress abrasion of the lip | rip part of the inner peripheral side of an oil seal, or a lip | rip part contact surface.

(Invention specific matters common to claim 1 and claim 3)
As illustrated in FIG. 2 or FIG. 3, the rotational transmission shaft (2) is inserted into the transmission case (1), and the internal transmission wheel (4) is disposed on the outer periphery of the rotational transmission shaft (2) in the transmission case (1). Is inserted, a transmission shaft insertion hole (5) is made in the case wall (3) of the transmission case (1), and the rotation transmission shaft (2) is projected outside the transmission case (1) through the transmission shaft insertion hole (5). The outer transmission wheel (7) is fitted on the outer periphery of the protrusion (6) of the rotary transmission shaft (2) outside the transmission case (1), and the outer periphery of the rotary transmission shaft (2) is inserted in the transmission shaft insertion hole (5). A lip contact surface (2a) is provided on the side, an oil seal (9) is fitted to the inner periphery of the transmission shaft insertion hole (5), and the lip portions (9a) (9b) on the inner periphery side of the oil seal (9) A sealing device for the transmission case of the engine, which is in contact with the lip contact surface (2a) on the outer peripheral side of the rotary transmission shaft (2).

(Invention specific matter specific to claim 1)
As illustrated in FIG. 2, the axial direction of the rotary transmission shaft (2) is the front-rear direction and the protruding direction of the rotary transmission shaft (2) is the front.
Cover the oil seal (9) from the front side with the external transmission wheel (7),
Engine transmission characterized in that a front lip portion (9c) is provided on the oil seal (9), and the front lip portion (9c) is brought into contact with the rear surface (7a) of the external transmission wheel (7). Case sealing device.

(Invention specific matter specific to claim 3)
As illustrated in FIG. 3, a collar (8) is fitted on the outer periphery of the rotary transmission shaft (2) in the transmission shaft insertion hole (5), and the lip portions (9a) (9b) on the inner peripheral side of the oil seal (9). ) In contact with the lip contact surface (2a) of the outer peripheral surface of the collar (8)
A flange (8b) is formed on the collar (8) with the axial direction of the rotational transmission shaft (2) in the front-rear direction and the protruding direction of the rotational transmission shaft (2) as the front, and an oil seal (9 ) From the front,
An oil transmission case is provided with an oil seal (9) provided with a front lip portion (9c), and the front lip portion (9c) is brought into contact with a rear surface (8c) of a flange (8b). Sealing device.

(Invention of Claim 1)
The invention according to claim 1 has the following effects.
<Effect> It is possible to suppress wear of the lip portion on the inner peripheral side of the oil seal and the lip contact surface.
As illustrated in FIG. 2, the oil transmission (7) covers the oil seal (9) from the front side, and the oil seal (9) is provided with a front lip portion (9c). The front lip portion (9c) Is brought into contact with the rear surface (7a) of the external transmission wheel (7), so that dust or muddy water is not applied to the inner lip (9a) (9b) or the lip contact surface (2a) of the oil seal (9). Can be prevented by the external transmission wheel (7) and the front lip portion (9c), and the lip portion (9a on the inner peripheral side of the oil seal (9) due to the entrapment of foreign matters such as dust and mud. ) (9b) and wear of the lip portion contact surface (2a) can be suppressed.

<Effect> The number of parts does not increase.
As illustrated in FIG. 2, the oil transmission (7) covers the oil seal (9) from the front side, and the oil seal (9) is provided with a front lip portion (9c). The front lip portion (9c) Is brought into contact with the rear surface (7a) of the external transmission wheel (7), so that the number of parts does not increase.

(Invention of Claim 2)
The invention according to claim 2 has the following effect in addition to the effect of the invention according to claim 1.
<Effect> It is possible to suppress wear of the lip portion on the inner peripheral side of the oil seal and the lip contact surface.
As illustrated in FIG. 2, the boss (11) of the transmission shaft insertion hole (5) protrudes forward from the case wall (3) of the transmission case (1), and an oil seal (9) is inserted into the boss (11). , The cylinder (7b) is led out from the external transmission wheel (7), and the inner peripheral surface (7c) of the cylinder (7b) is aligned with the outer peripheral surface (11a) of the boss (11). The inlet of (7b) is bent along the outer peripheral surface (11a) and the front end surface (11b) of the boss (11), and dust and muddy water enter between the external transmission wheel (7) and the transmission case (1). Thus, it is possible to suppress wear of the lip portions (9a) and (9b) and the lip portion contact surface (2a) on the inner peripheral side of the oil seal (9) due to the inclusion of foreign matters such as dust and mud.

(Invention of Claim 3)
The invention according to claim 3 has the following effects.
<Effect> It is possible to suppress wear of the lip portion on the inner peripheral side of the oil seal and the lip contact surface.
As illustrated in FIG. 3, a flange (8b) is formed on the collar (8) with the axial direction of the rotary transmission shaft (2) in the front-rear direction and the protruding direction of the rotary transmission shaft (2) as the front. (8b) covers the oil seal (9) from the front side, and the oil seal (9) is provided with a front lip portion (9c), and the front lip portion (9c) is provided on the rear surface (8c) of the flange (8b). Because of the contact, dust and muddy water approach the lip (9a) (9b) and the lip contact surface (2a) on the inner peripheral side of the oil seal (9). 8b) and the front lip portion (9c), which can be obstructed by the lip portions (9a) (9b) and lip portion contact surfaces on the inner peripheral side of the oil seal (9) due to the inclusion of foreign matter such as dust and mud The wear of (2a) can be suppressed.

<Effect> The number of parts does not increase.
As shown in FIG. 3, a flange (8b) is formed on the collar (8), the oil seal (9) is covered with the flange (8b) from the front side, and the front lip (9c) is formed on the oil seal (9). ) And the front lip portion (9c) is brought into contact with the rear surface (8c) of the flange (8b), so that the number of parts does not increase.

(Invention of Claim 4)
The invention according to claim 4 has the following effects in addition to the effects of the invention according to any one of claims 1 to 3.
<Effect> It is possible to suppress wear of the lip portion on the inner peripheral side of the oil seal and the lip contact surface.
As illustrated in FIG. 2 or FIG. 3, the front facing portion (7 d) (8 d) of the oil seal (9) is closer to the rotational transmission shaft (2) than the front lip (9 c) of the oil seal (9). Since the stopper ridges (7e) and (8e) are projected rearward from each other, and the stopper ridges (7e) and (8e) are oriented in the direction along the inner peripheral surface of the front lip portion (9c), an oil seal (9 ), The stopper ridge (10b) can prevent dust and muddy water from approaching the inner peripheral lip (9a) (9b) and the lip contact surface (2a). It is possible to suppress wear of the lip portions (9a) (9b) and the lip portion contact surface (2a) on the inner peripheral side of the oil seal (9) due to the biting of foreign matter.

<Effect> It is possible to prevent uneven wear and damage of the front lip.
As illustrated in FIG. 2 or FIG. 3, when the front lip portion (9 c) is about to be twisted to the rotational transmission shaft (2) side, the front lip portion (9 c) is moved to the stopper protrusion (7 e). (8e) so that the front lip portion (9c) can be prevented from being twisted and bent to the rotating transmission shaft (2) side, and uneven wear or damage to the front lip portion (9c) is prevented. Can be prevented.
Note that the front lip portion (9c) is twisted and bent toward the rotational transmission shaft (2) side when the external transmission wheel (7) and the collar (8) are attached, the position of the front lip portion (9c) is the rotational transmission shaft. (2) If the front lip (9c) rotates while the engine is running and is dragged by the outer transmission wheel (7) or the flange (8b) of the collar (8), or the outer transmission wheel (7) The collar (8) is immersed in the muddy water, and the front lip (9c) is pushed toward the rotary transmission shaft (2) by the muddy water entering the flange (8b) of the outer transmission wheel (7) and the collar (8). It happens when it happens.

(Invention according to claim 5)
The invention according to claim 5 has the following effects in addition to the effects of the invention according to any one of claims 1 to 4.
<Effect> It is possible to suppress wear of the lip portion on the inner peripheral side of the oil seal and the lip contact surface.
As illustrated in FIG. 2 or FIG. 3, since the lubricant (12) is filled between the front lip portion (9c) and the inner lip portion (9b) of the oil seal (9), the oil seal The lubricant (12) can prevent dust and muddy water from approaching the inner peripheral lip (9a) (9b) and the lip contact surface (2a) of (9). It is possible to suppress wear of the lip portions (9a) (9b) and the lip portion contact surface (2a) on the inner peripheral side of the oil seal (9) due to the biting of foreign matter.

1A and 1B are views for explaining a sealing device for an engine transmission case according to a first embodiment of the present invention, in which FIG. 1A is a longitudinal side view, and FIG. 1B is a rear view of an oil seal cover as viewed from the rear side. is there. It is an expanded sectional view of the II section of Drawing 1 (A). FIG. 3 is a view corresponding to FIG. 2 for explaining a sealing device for an engine transmission case according to a second embodiment of the present invention.

  FIGS. 1 and 2 are views for explaining a sealing device for an engine transmission case according to a first embodiment of the present invention, and FIG. 3 is a diagram for explaining a sealing device for an engine transmission case according to a second embodiment of the present invention. It is. In each embodiment, a sealing device for a timing transmission gear case of a diesel engine will be described.

The configuration of the first embodiment shown in FIG. 1 is as follows.
As shown in FIG. 1 (A), the rotary transmission shaft (2) is inserted into the transmission case (1), and the internal transmission wheel (4) is placed on the outer periphery of the rotary transmission shaft (2) in the transmission case (1). The transmission shaft insertion hole (5) is made in the case wall (3) of the transmission case (1), and the rotary transmission shaft (2) is projected outside the transmission case (1) through the transmission shaft insertion hole (5). The outer transmission wheel (7) is fitted on the outer periphery of the projecting portion (6) of the rotary transmission shaft (2) outside the transmission case (1), and the outer peripheral side of the rotary transmission shaft (2) in the transmission shaft insertion hole (5). 2 is provided with a lip contact surface (2a), and an oil seal (9) is fitted to the inner periphery of the transmission shaft insertion hole (5). As shown in FIG. 2, the lip portion on the inner periphery side of the oil seal (9) (9a) and (9b) are brought into contact with the lip portion contact surface (2a) on the outer peripheral side of the rotation transmission shaft (2).

As shown in FIG. 1A, the transmission case (1) is a timing transmission gear case (13), and a timing transmission gear train is accommodated in the timing transmission gear case (13).
The rotation transmission shaft (2) is a crankshaft (14).
The internal transmission wheel (4) is a crank gear (15), which is one of the components of the timing transmission gear train. The crank gear (15) is secured to the rotary transmission shaft (2) by a key (21) and a key groove (22).
The external transmission wheel (7) is a pulley (16), and transmits power to the engine cooling fan and the cooling water pump via the transmission belt. The pulley (16) is secured to the rotation transmission shaft (2) by a key (17) and a key groove (18).

  As shown in FIG. 2, the lip portion (9a) (9a) on the inner peripheral side of the oil seal (9) with the axial direction of the rotational transmission shaft (2) as the front-rear direction and the protruding direction of the rotational transmission shaft (2) as the front. 9b) is composed of a rear oil seal lip portion (9a) and a front dust seal lip portion (9b). The oil seal (9) is an annular rubber ring in which a metal ring (23) is embedded, and the oil seal lip (9a) is a seal contact surface from the oil seal (9) to the outer peripheral side of the rotary transmission shaft (2). Derived obliquely backward toward (2a), tightened in the center direction by an annular coil spring (24), and the tip is brought into pressure contact with the seal contact surface (2a) on the outer peripheral side of the rotary transmission shaft (2). The dust seal lip (9b) is led obliquely forward from the oil seal (9) toward the seal contact surface (2a) on the outer peripheral side of the rotary transmission shaft (2), and the tip rotates by the elastic restoring force of the rubber material. It is brought into pressure contact with the seal contact surface (2a) on the outer peripheral side of the transmission shaft (2). The lip portions (9a) and (9b) on the inner peripheral side of the oil seal (9) are both in an annular shape along the circumferential direction of the oil seal (9).

As shown in FIG. 2, the oil seal (9) is covered from the front side with the external transmission wheel (7),
The oil seal (9) is provided with a front lip portion (9c), and the front lip portion (9c) is brought into contact with the rear surface (7a) of the external transmission wheel (7).

  As shown in FIG. 1 (B), the external transmission wheel (7) has an annular shape and is made of cast iron. The front lip portion (9c) is a dust seal lip portion, which is led out from the oil seal (9) toward the oil seal cover (10), and its tip is inclined toward the radially outer side of the oil seal cover (10). The front end is brought into contact with the oil seal cover (10) by the elastic restoring force of the rubber material. The front lip (9c) is annular.

As illustrated in FIG. 2, the boss (11) of the transmission shaft insertion hole (5) protrudes forward from the case wall (3) of the transmission case (1), and an oil seal (9) is inserted into the boss (11). Fit,
The cylinder (7b) is led backward from the external transmission wheel (7), and the inner peripheral surface (7c) of the cylinder (7b) is aligned with the outer peripheral surface (11a) of the boss (11). The boss (11) is cylindrical, and the outer periphery of the front end is chamfered in an arc shape.

As shown in FIG. 2, the stopper ridge (backwardly facing from the front facing portion (7 d) of the oil seal (9) on the rotational transmission shaft (2) side of the lip portion (9 c) on the front side of the oil seal (9). 7e) is projected, and the stopper ridge (7e) is oriented in a direction along the inner peripheral surface of the front lip portion (9c), so that the front lip portion (9c) is moved to the rotational transmission shaft (2) side. When twisted and bent, the front lip portion (9c) can be received by the stopper protrusion (7e).
As shown in FIG. 1 (A), the stopper protrusion (10b) has an annular shape along the circumferential direction of the external transmission wheel (7), and as shown in FIG. 2, a part of the rear surface of the external transmission wheel (7). Is formed by bulging backwards.

  As shown in FIG. 2, a lubricant (12) is filled between the front lip portion (9c) and the inner peripheral lip portion (9b) of the oil seal (9). The lubricant (12) is grease, and the dust seal lip (9c) on the front side of the oil seal (9), the dust seal lip (9b) on the inner peripheral side, the external transmission wheel (7), and the rotary transmission shaft (2) The space surrounded by the outer peripheral seal contact surface (2a) is filled.

As shown in FIG. 2, a collar (8) is fitted to the outer periphery of the rotary transmission shaft (2) in the transmission shaft insertion hole (5), and the outer peripheral surface (8a) of the collar (8) is attached to the rotary transmission shaft (2 ) On the outer peripheral side of the collar (8), a nitriding layer is formed on the outer peripheral surface (8a) of the collar (8), and a sulfurating layer is provided on the outermost surface of the nitriding layer.
The collar (8) is made of a cylindrical steel material.
The nitriding layer is formed not only on the outer peripheral surface of the cylindrical steel material but also on the inner peripheral surface.
In order to form a nitriding layer on the surface of a cylindrical steel material, the following is performed.
By exposing a cylindrical steel containing nitride-forming elements such as aluminum, chromium and molybdenum to an atmosphere containing ammonia or nitrogen and heating it in the temperature range below the austenitizing temperature, the surface of the cylindrical steel is near ( 1 mm or less) is infiltrated with nitrogen and cured. The surface hardness of the color (8) is 900 HV or more in terms of Vickers hardness.
The sulfuration treatment layer is a sulfide layer of several microns formed on the nitride compound layer by gas oxynitridation or the like.
As described above, since the nitriding layer is formed on the outer peripheral surface (8a) of the collar (8), the collar (8) has excellent wear resistance and durability exceeding the service life of the engine can be obtained. The exchange of 8) becomes unnecessary. Further, since the sulfuration treatment layer is provided on the outermost surface of the nitridation treatment layer, the lubricity of the collar (8) is high.

  As shown in FIG. 2, the axial direction of the rotary transmission shaft (2) is the front-rear direction, and the collar (8) is a front-rear symmetrical shape. That is, the shape of the collar (8) due to the chamfering of the end portion or the radius is made symmetrical in the front-rear direction. For this reason, even if the collar (8) is fitted to the rotary transmission shaft (2) from either end, the collar (8) is not assembled incorrectly, and oil leakage from the collar (8) due to this is prevented. be able to. Further, the assembling work of the collar (8) is simplified.

  As shown in FIG. 1, the rear end face of the internal transmission wheel (4) is brought into contact with the seat (19) of the rotary transmission shaft (2), and the collar (8) is attached to the front side of the internal transmission wheel (4). Place the external transmission wheel (7) on the front side of the collar (8), and apply the pressure backward by the fastening force of the fastener (20) attached to the rotation transmission shaft (2). The collar (8) and the internal transmission wheel (4) are sandwiched between the seat (19) of the rotary transmission shaft (2) and the external transmission wheel (7). The fastener (40) is a fastening nut. The external transmission wheel (7) and the collar (8) rotate integrally with the rotary transmission shaft (2). The arrow (23) shown in FIG. 1 (B) indicates the direction of rotation of the external transmission wheel (7) as viewed from the rear side. It is a turning direction.

In the second embodiment shown in FIG. 3, a flange (8b) is formed on the collar (8), the oil seal (9) is covered with the flange (8b) from the front side, and the front lip is formed on the oil seal (9). (9c) is provided, and the front lip portion (9c) is brought into contact with the rear surface (8c) of the flange (8b), and other configurations are the same as those of the first embodiment. In FIG. 3, the same elements as those in the first embodiment are denoted by the same reference numerals as those in FIG.
As in the first embodiment, the collar (8) is nitrided, a nitriding layer is formed on the rear surface (8c) of the flange (8b), and the nitriding treatment is applied to the outermost surface of the nitriding layer. A layer is provided.

(1) Transmission case
(2) Rotating transmission shaft
(2a) Lip part contact surface
(3) Case wall
(4) Internal transmission wheel
(5) Transmission shaft insertion hole
(6) Protruding part
(7) External transmission wheel
(7a) Rear side
(7b) Tube
(7c) Inner peripheral surface
(7d) Front facing part
(7e) Stopper protrusion
(8) Color
(8a) Outer surface
(8b) Flange
(8c) Rear side
(8d) Front facing part
(8e) Stopper protrusion
(9) Oil seal
(9a) Inner lip
(9b) Inner lip
(9c) Front lip
(11) Boss
(11a) Outer peripheral surface
(12) Lubricant

Claims (5)

Insert the rotation transmission shaft (2) into the transmission case (1), fit the inner transmission wheel (4) to the outer periphery of the rotation transmission shaft (2) in the transmission case (1), and the case wall of the transmission case (1). The transmission shaft insertion hole (5) is opened in (3), the rotation transmission shaft (2) is projected outside the transmission case (1) through the transmission shaft insertion hole (5), and the rotation transmission is performed outside the transmission case (1). The outer transmission wheel (7) is fitted on the outer periphery of the protruding portion (6) of the shaft (2), and the lip contact surface (2a) is provided on the outer peripheral side of the rotary transmission shaft (2) in the transmission shaft insertion hole (5). The oil seal (9) is fitted to the inner periphery of the transmission shaft insertion hole (5), and the inner peripheral lip portions (9a) and (9b) of the oil seal (9) are connected to the outer peripheral side of the rotary transmission shaft (2). In the sealing device for the transmission case of the engine, which is in contact with the lip contact surface (2a),
With the axial direction of the rotary transmission shaft (2) as the longitudinal direction and the protruding direction of the rotary transmission shaft (2) as the front,
Cover the oil seal (9) from the front side with the external transmission wheel (7),
Engine transmission characterized in that a front lip portion (9c) is provided on the oil seal (9), and the front lip portion (9c) is brought into contact with the rear surface (7a) of the external transmission wheel (7). Case sealing device. The sealing device for the transmission case of the engine according to claim 1,
The boss (11) of the transmission shaft insertion hole (5) protrudes forward from the case wall (3) of the transmission case (1), and an oil seal (9) is fitted into the boss (11).
The cylinder (7b) is led backward from the external transmission wheel (7), and the inner peripheral surface (7c) of the cylinder (7b) is aligned with the outer peripheral surface (11a) of the boss (11). Sealing device for engine transmission case. Insert the rotation transmission shaft (2) into the transmission case (1), fit the inner transmission wheel (4) to the outer periphery of the rotation transmission shaft (2) in the transmission case (1), and the case wall of the transmission case (1). The transmission shaft insertion hole (5) is opened in (3), the rotation transmission shaft (2) is projected outside the transmission case (1) through the transmission shaft insertion hole (5), and the rotation transmission is performed outside the transmission case (1). The outer transmission wheel (7) is fitted on the outer periphery of the protruding portion (6) of the shaft (2), and the lip contact surface (2a) is provided on the outer peripheral side of the rotary transmission shaft (2) in the transmission shaft insertion hole (5). The oil seal (9) is fitted to the inner periphery of the transmission shaft insertion hole (5), and the inner peripheral lip portions (9a) and (9b) of the oil seal (9) are connected to the outer peripheral side of the rotary transmission shaft (2). In the sealing device for the transmission case of the engine, which is in contact with the lip contact surface (2a),
The collar (8) is fitted to the outer periphery of the rotary transmission shaft (2) in the transmission shaft insertion hole (5), and the lip portions (9a) and (9b) on the inner peripheral side of the oil seal (9) are connected to the outer periphery of the collar (8). When contacting the lip contact surface (2a) of the surface,
A flange (8b) is formed on the collar (8) with the axial direction of the rotational transmission shaft (2) in the front-rear direction and the protruding direction of the rotational transmission shaft (2) as the front, and an oil seal (9 ) From the front,
An oil transmission case is provided with an oil seal (9) provided with a front lip portion (9c), and the front lip portion (9c) is brought into contact with a rear surface (8c) of a flange (8b). Sealing device. The engine transmission case sealing device according to any one of claims 1 to 3,
Stopper ridges (7e) (8e) facing backward from the front facing locations (7d) (8d) of the oil seal (9) on the side of the rotational transmission shaft (2) relative to the front lip portion (9c) of the oil seal (9) ) And the stopper ridges (7e) and (8e) are oriented in the direction along the inner peripheral surface of the front lip portion (9c), so that the front lip portion (9c) is rotated by the rotation transmission shaft (2). A sealing device for an engine transmission case, characterized in that the front lip portion (9c) can be received by the stopper protrusions (7e) (8e) when twisted to the side. In the sealing device of the transmission case of the engine according to any one of claims 1 to 4,
An engine transmission case sealing device, wherein a lubricant (12) is filled between a front lip portion (9c) and an inner peripheral lip portion (9b) of an oil seal (9).

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