JPH0313638Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Field of Application of the Invention" This invention relates to a dust seal used for the front fork of a motorcycle, etc.

``Problems to be solved by conventional techniques and ideas'' As shown in Figures 4 and 5, this type of conventional dust seal has a relatively large area from the upper circumferential surface of the sealing part of the seal lip to the tip surface of the seal lip and the outer circumferential surface. It is formed into a gently curved surface, and the corner between the upper circumferential surface of the seal part and the end surface of the seal lip forms an obtuse angle, so that fine dust tends to adhere in a series from the seal part to the end surface of the seal lip.
A small amount of lubricating oil is scraped out from around the shaft by the seal part and seeps into a series of adhered dust particles, which ooze out continuously from the tip of the seal lip to the outer circumferential surface due to capillary action. In addition to the surface becoming extremely dirty, the lubricating oil in the seal portion is gradually lost, resulting in increased friction and wear due to insufficient lubrication of the seal portion.

``Means for solving problems'' This invention aims to solve the above-mentioned conventional problems.
An inward annular protrusion that does not contact the shaft is provided on the inner circumferential surface of the seal lip on the distal side of the seal portion, and the protrusion extends from the upper circumferential surface of the seal lip located on the distal end side of the seal lip to the proximal end of the seal lip on the protrusion. A dust seal is proposed in which a groove-shaped folded and inverted surface is formed on the lower circumferential surface.

"Operation" When fine dust adheres to the upper circumferential surface of the seal part, even if the lubricating oil scraped from the shaft seeps into the dust, the lower circumferential surface of the protrusion that is folded back from the upper circumferential surface and forms an inverted shape. This makes it difficult for the oil to seep out to the tip side of the seal lip, and the oil is retained in the groove between the seal part and the protrusion.In addition, since it is difficult for dust to adhere to the sharp tip of the protrusion, the oil in the dust is Oil leakage due to capillary action is effectively prevented, thereby preventing the outer peripheral surface of the seal lip from becoming contaminated and the sealing portion from running out of lubrication.

``Example'' Below, an example of this invention shown in the drawings will be described. A seal portion 3 that contacts a shaft 2 of a fork pipe or the like is provided on the inner periphery of the tip of the seal lip 1 of the dust seal. A sharp-pointed protrusion 4 is provided on the inner peripheral surface of the distal end side of the protrusion 1 so as not to come into contact with the shaft 3.

Therefore, as shown in FIG. 3, a groove is formed from the upper circumferential surface 3a of the seal portion 3 located on the distal end side of the seal lip 1 to the lower circumferential surface 4a of the protrusion 4 located on the proximal end side of the seal lip 1. A folded and inverted surface having a shape is formed.

In the above configuration, the upper circumferential surface 3 of the seal portion 3
If fine dust adheres to a, even if the lubricating oil scraped out from the shaft 2 seeps into the dust, the seal lip can be removed by the lower circumferential surface 4a of the protrusion 4, which is folded back from the upper circumferential surface 3a and forms an inverted shape. It becomes difficult for the oil to leak to the tip side of 1, and the oil is transferred to the seal part 3 and the protrusion 4.
Since it is held in the groove between the seal lip 1 and the seal lip 1, dirt on the outer circumferential surface of the seal lip 1 and loss of lubrication of the seal portion 3 are reliably prevented.

In particular, since dust is difficult to adhere to the sharp tip of the protrusion 4, oozing of oil due to capillary action in the dust is effectively prevented.

``Effects of the invention'' As described above, according to this invention, the oil scraped from the shaft is reliably retained in the groove between the seal part and the protrusion, preventing it from leaking toward the outer peripheral surface. It is possible to prevent dirt and loss of lubrication of the seal part.

[Brief explanation of the drawing]

Fig. 1 is a partial longitudinal sectional view showing an embodiment of this invention, Fig. 2 is a partial longitudinal sectional view showing another embodiment of this invention, and Fig. 3 is an enlarged longitudinal sectional view of the tip of the seal lip according to this invention. , 4 and 5 are partial vertical sectional views showing a conventional dust seal. 1...Seal lip, 2...Shaft, 3...Seal portion, 3a...Surrounding surface, 4...Protrusion.

Claims (1)

[Scope of utility model registration request] An inward annular protrusion that does not contact the shaft is provided on the inner circumferential surface of the seal lip on the distal side of the seal portion, and the protrusion is located on the proximal side of the seal lip from the upper circumferential surface located on the distal end side of the seal lip in the seal portion. A dust seal characterized in that a groove-shaped folded and inverted surface is formed on the lower circumferential surface of the dust seal.