JP2541851Y2 - Sealing device for two-stroke engine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device used to partition a cylinder chamber and a gear chamber or a cylinder chamber and a clutch chamber of a two-cycle engine of a motorcycle.

[0002]

2. Description of the Related Art FIG. 5 shows an example of this type of sealing device. The sealing device 1 in the illustrated example is obtained by attaching an elastic body 3 such as rubber to a core metal ring 2 having an approximately L-shaped cross section. The elastic body 3 is attached thinly on the entire outer surface of the metal core ring 2. In addition, first and second seal lips 5 and 6 are formed on the inner peripheral edge of the annular disk portion 4 of the metal core ring 2.

[0003] Then, the cylindrical portion 7 of the cored bar ring 2 is attached by being press-fitted to the inner peripheral surface of the outer member 8 indicated by a virtual line.

[0004] The first seal lip 5 and the second seal lip 6 are bifurcated in the direction away from each other in the axial direction and are formed in a C-shape. A garter spring 9 is mounted. In the case of the first seal lip 5, when the pressure in the left space in the drawing becomes higher than the pressure in the right space in the drawing across the sealing device 1, the contact pressure against the outer peripheral surface of the inner member 10 indicated by the imaginary line is reduced. In the case of the second seal lip 6, when the pressure in the right space in the drawing becomes higher than the pressure in the left space in the drawing, the contact pressure against the outer peripheral surface of the inner member 10 increases.

[0005]

SUMMARY OF THE INVENTION By the way, due to the improvement of fuel efficiency and performance in a two-cycle engine, the sealing and partitioning performance of a sealing device that separates a cylinder chamber and a gear chamber or a cylinder chamber and a clutch chamber is reduced. Although there has been a tendency to demand higher performance, it is difficult for the above-mentioned conventional sealing device 1 to respond to the above demand.

Further, in the case of the conventional sealing device 1, when the pressure in the cylinder chamber becomes high and the pressure difference between the gear chamber and the clutch chamber becomes large, the resistance against disengagement from the outer member 8 is insufficient. One point is pointed out.

The present invention has been made in view of such circumstances, and aims to improve the performance in terms of sealing performance and pressure resistance, and to increase the pressure difference between the spaces on both sides sandwiching the sealing device. The purpose of the present invention is to prevent the detachment of the sealing device at the time.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a two-cycle engine mounted on a substantially L-shaped peripheral step provided on an inner peripheral shoulder of a cylindrical member.
The gin sealing device has the following configuration.

The sealing device for a two-stroke engine according to the present invention has a metal core ring and a seal lip made of an elastic material. The metal core ring has an annular disk portion attached to the peripheral step, and An elastic body connected to the seal lip is attached to an outer surface of the annular disk portion and one side surface of the body portion, and The side surface on which the elastic body is attached in the annular disk portion abuts on the step wall surface of the peripheral step portion, and the outer peripheral edge of the annular disk portion is formed on the peripheral groove provided near the step surface on the step bottom surface of the peripheral step portion. The main body is axially mounted from the base end of the annular disk portion.
At the outside, and radially inward from the tip.
In the axial and radial directions from the tip.
And extend from the tip
It has a bent shape that extends inward in the radial direction,
The two seal lips are provided symmetrically on the inner peripheral edge of the main body of the cored bar ring, and are urged to urge the seal lips radially inward on the outer periphery of the two seal lips. It is characterized in that the member is mounted.

[0010]

In the above construction, since the hard core ring of the sealing device is elastically fitted into the peripheral groove of the peripheral portion of the cylindrical member, the engagement with the peripheral portion of the sealing device is increased, and the pressure resistance is increased. The performance is improved as compared with the conventional press-fitting. For this reason, even if pressure is applied to the sealing device in a direction of detaching the sealing device, the trapping prevents the sealing device from tilting or coming off.

Further , the main body of the metal core ring has an annular disk portion.
In the axial direction from the proximal end extending outwardly from the tip
Extend inward in the radial direction, and from the tip
Extend in an oblique direction that is inward in both directions.
And a bent shape that extends radially inward from the tip
Shape, the cross-sectional shape of the
It has a stable structure with increased
Bending shape when load is applied from either side
The shape expands radially, that is, the body extends downward
To press the seal lip against the inner ring, thereby providing high sealing
Property is obtained. Also, since two seal lips are provided on the inner peripheral edge of the main body of the cored bar ring, and each seal lip is biased by a biasing member to increase the contact pressure against the outer peripheral surface of the inner member such as the shaft, It is possible to further improve the sealing performance.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the present invention. In the figure, 20 is a sealing device, and 30 is a ball bearing.
Here, an example in which the sealing device 20 is mounted on a ball bearing 30 is used, and this ball bearing 30 is used as a support bearing D at an end of the crankshaft A on the gear chamber B side in the two-cycle engine shown in FIG. The cylinder chamber C and the gear chamber B are partitioned by the sealing device 20 built in the ball bearing 30.

In this case, the sealing device 20 is arranged on the side of the cylinder chamber C of the ball bearing 30 (the left side in FIG. 4). Accordingly, the ball bearing 30 is lubricated by the lubricating oil on the gear chamber B side, which is more lubricating than the conventional case in which a sealing device is disposed on the gear chamber B side of the ball bearing 30 and lubricated with the mixture in the cylinder chamber. Performance improves.

The sealing device 20 includes a metal core ring 40.
Seal lips 50 and 51 made of rubber or the like are attached to the outer ring 31. FIG. 2 shows the shape of the ball bearing 30 before being mounted on the outer ring 31, and FIG. 1 shows the shape after mounting.

That is, the metal core ring 40 has a body portion 41 having a substantially inverted L-shaped cross section, and an inclined posture which is integrally connected to the outer peripheral edge of the body portion 41 and extends obliquely upward before mounting. And an annular disk portion 42 extending radially outward and in a straight posture after mounting. The main body 41 is
The vicinity of the radial center of the annular portion 41a along the radial direction is bent. In other words, below the radial center position of the main body portion 41, first, it is bent obliquely downward toward the inside of the bearing, and further straightly extends radially inward from there. In addition, an elastic body 60 such as rubber is thinly applied so as to cover the outer peripheral edge of the annular disk portion 42 from one side surface of the main body portion 41 and one entire side surface of the annular disk portion 42 to the other side surface. .

The seal lips 50 and 51 are
The main body 41 is attached to the inner peripheral edge of the main body 41 and is provided symmetrically in the axial direction with the main body 41 interposed therebetween. Each of the seal lips 50 and 51 has a substantially triangular cross-section, and a circumferential groove that is recessed inward in the radial direction is provided at the center in the axial direction at each outer peripheral portion. (Corresponding to the biasing member in the claims) is mounted.

The ball bearing 30 has an outer ring 31 (corresponding to a cylindrical member in the claims), an inner ring 32, a ball 33, and a retainer 34. Is provided with a peripheral step 35 whose upper half section is substantially inverted L-shaped, and the sealing device 20 is attached to the peripheral step 35. A peripheral groove 36 that is recessed radially outward is formed in a portion of the peripheral step portion 35 near the step wall surface 35b on the step bottom surface 35a. The inner diameter of the step bottom 35a of the peripheral step 35 is
The outer diameter of the peripheral groove 36 is set slightly smaller than the outer diameter of the sealing device 20 before mounting in FIG. 2, and the inner diameter of the circumferential groove 36 is slightly smaller than the outer diameter of the sealing device 20 after mounting in FIG. It is set small.

Next, the procedure for mounting the sealing device 20 will be described.

First, the peripheral step 35 of the outer race 31 of the ball bearing 30
Next, the sealing device 20 is positioned as shown in FIG. Therefore, a cylindrical jig 80 is applied to the outer surface of the annular disk portion 42 of the core ring 40 of the sealing device 20, and this jig 8
By pressing 0 in the direction of the arrow, the sealing device 20 is pushed deep into the peripheral step 35 of the outer race 31. By this pushing operation, the annular disk portion 42 of the core ring 40 of the sealing device 20 is deformed as follows. First, in a state where the outer peripheral edge of the annular disk portion 42 is in contact with the step wall surface 35b of the peripheral step portion 35, the annular disk portion 42 is pushed along the step wall surface 35b in order to push the annular disk portion 42 toward the step wall surface 35b. Circular disk part 42
The annular disc portion 42 starts to open in the direction of the arrow in FIG. At this time, since the cylindrical portion of the main body portion 41 is supported by the inner peripheral surface of the jig 80, only the annular disk portion 42 is deformed from the boundary between the cylindrical portion of the main body portion 41 and the annular disk portion 42. Will do. When the circular disk portion 42 is in a straight posture along the radial direction, the outer peripheral edge of the circular disk portion 42 and a part of the elastic body 60 attached thereto are partially covered with the circumferential groove 3 of the peripheral step portion 35.
6 (see FIG. 1). In addition, the elastic body 60 wrapping the outer peripheral edge of the annular disk portion 42 absorbs the play between the circumferential groove 36 and the annular disk portion 42 and secures the sealing performance.

Next, the operation will be described.

As described above, the core metal ring 40 is connected to the outer race 31.
It is necessary to deform the boundary portion between the annular disc portion 42 and the cylindrical portion of the main body portion 41 when fixing the core metal ring 40, so that the plate thickness of the core metal ring 40 is made thinner than that of the conventional one, for example, When the pressure on the outer side of the bearing becomes higher than the pressure on the inner side of the bearing and the pressure difference on both sides increases, the core metal ring 40
The main body 41 is bent, but since the main body 41 is provided with a bent portion, the bent portion causes the bent portion to expand in the radial direction.
0 and 51 are pressed against the inner ring 32 of the ball bearing 30. When the pressure difference between the two sides of the sealing device 20 is large, the inner rings 32 of the seal lips 50 and 51 may be used.
It has the function of increasing the contact pressure with the air and increasing the sealing performance there.

In each of the above embodiments, the example in which the sealing device 20 is mounted on the rolling bearing is described. However, the mounting device of the sealing device 20 is not limited to the rolling bearing. The sliding surfaces of the seal lips 50 and 51 may be replaced by the inner ring 32 and the crankshaft A.

In addition to the ball bearing 30 described above, a cylindrical roller bearing 90 shown in FIG. 3 is used as the bearing D for supporting the end of the crankshaft A on the gear chamber B side in the two-cycle engine shown in FIG. be able to. The illustrated cylindrical roller bearing 90 includes an outer ring 91, a cylindrical roller 92, and a retainer 93.
And the crankshaft A is used as an inner ring. On the shaft end shoulder of the inner peripheral surface of the outer ring 91,
As in the case of the ball bearing 30, a peripheral step 94 having an upper half section having a substantially inverted L-shape is provided, and the above-described sealing device 20 is attached to the peripheral groove 95 of the peripheral step 94. An oil hole 97 for introducing lubricating oil is provided at several locations on the circumference at the axial center of the raceway groove 96 of the outer ring 91. When this cylindrical roller bearing 90 is used, the arrangement state in the two-cycle engine shown in FIG. 4 is set such that the sealing device 20 is located on the clutch chamber B side.

[0025]

As described above, according to the present invention, the hard edge of the rigid metal core ring of the sealing device is fitted into the circumferential groove of the peripheral step of the cylindrical member to which the sealing device is to be attached, so that the catch is strongly reduced. As a result, the sealing device can be strongly held at the peripheral step, and the pressure resistance is improved.

The body of the core ring has a bent shape.
The rigidity is high because the
It has a stable structure,
The bent shape is the diameter even if the load is received from either side
Direction, i.e., the body extends downward and
Press the rlip against the inner ring to obtain high sealing performance
Can be

Further, two seal lips are provided so as to sandwich the main body of the metal core ring, and each seal lip is pressed against the outer peripheral surface of the inner member by the biasing member, so that the sealing performance is improved. .

[0028] Since attained is thus improved in pressure resistance and sealability, the sealing device of the present invention is of a two-stroke engine Shi
It is suitable for use in a part that separates a cylinder chamber and a clutch chamber from a cylinder chamber and a gear chamber .

[Brief description of the drawings]

FIG. 1 is a longitudinal side view showing an upper half of a ball bearing equipped with a sealing device of the present invention.

FIG. 2 is an enlarged sectional view of a main part showing a mounting process of the sealing device.

FIG. 3 is a longitudinal sectional side view showing an upper half of a cylindrical roller bearing equipped with the sealing device of the present invention.

FIG. 4 is a longitudinal sectional view showing a main part of the two-cycle engine.

FIG. 5 is a longitudinal sectional view of an upper half showing a conventional sealing device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 20 Sealing device 30 Ball bearing 31 Outer ring 35 Peripheral step 35a Step bottom 35b Step wall 36 Peripheral groove 40 Core ring 41 Main part 42 Annular disk part 50 First seal lip 51 Second seal lip 70 Garter spring

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Osamu Kimura 3-5-8 Minamisenba, Chuo-ku, Osaka City Inside Koyo Seiko Co., Ltd. (72) Inventor Hiroshi Hanura 3-5-8, Minamisenba, Chuo-ku, Osaka-shi No. Koyo Seiko Co., Ltd. (56) References Japanese Utility Model Showa 62-177921 (JP, U) Japanese Utility Model Showa 62-102024 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] 1. A sealing device for a two-stroke engine, which is attached to a peripheral step portion having a substantially L-shaped cross section provided on a shoulder portion on an inner peripheral surface of a cylindrical member, comprising a cored ring and an elastic body. A seal lip, wherein the metal core ring has an annular disk portion attached to the peripheral step portion, and a main body portion integrally formed on an inner periphery of the annular disk portion; An elastic body connected to the seal lip is attached to an outer surface of the portion and one side surface of the main body portion,
In addition, the side surface on which the elastic body is attached in the annular disk portion abuts against the step wall surface of the peripheral step portion, and the outer peripheral edge of the annular disk portion is provided near the step surface on the step bottom surface of the peripheral step portion. The main body is axially mounted from a base end of the annular disk portion.
And extend radially inward from the tip.
From the tip, inward in both the axial and radial directions.
And extend radially from the tip.
The seal lip is provided symmetrically on the inner peripheral edge of the main body of the metal core ring, and two seal lips are provided on the outer periphery of the two seal lips. A biasing member for biasing the seal lip radially inward is mounted.
Sealing device for two-cycle engine .