JPS6225904B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in oil seals used on rotating shafts.

Generally, as this type of oil seal, one constructed using an elastic material such as rubber or synthetic resin is known. Conventionally, an oil seal consists of a rubber annular body having a seal lip that comes into close contact with the outer circumferential surface of a rotating shaft, and a garter spring is appropriately attached to the outer circumference of the seal lip to hold the seal lip in pressure contact with the rotating shaft. Ru.
However, as the seal lip of an oil seal applied to a rotating shaft that rotates at high speeds wears, its sealing function decreases, eventually causing oil leakage.

From this point of view, conventionally, as shown in FIG.
A plurality of spiral protrusions 12 are provided on the 0b side to form a thread groove surface, so that even if the contact surface of the seal lip 10 with the rotating shaft 14 is slightly worn and oil leaks, the thread groove surface of the seal lip 10 and A structure has been proposed and implemented in which an axial flow pump effect is exerted by the rotation of the rotary shaft 14, and the leaking oil is pushed back to the oil side 10a of the seal lip 10. In addition, reference numeral 16 in FIG. 1 indicates a garter spring.

However, the oil seal constructed in this way has a complicated structure, which not only makes machining troublesome, but also increases the number of defects on the thread groove surface during molding, increases manufacturing costs, and requires high-speed processing. In those applied to rotating shafts, there is a limit to the durability of the sealing effect, and the sealing effect is not satisfactory.

In addition, as a means to improve the durability of the sealing effect as described above, the structure of the seal lip is formed with multiple layers of different materials in the axial direction, and minute uneven surfaces are created on the sealing surface based on the differences in these materials. It is known that the structure is as follows. However, forming a seal lip with multiple layers of different materials with appropriate thicknesses in the axial direction not only requires advanced processing technology, but also prevents unexpected oil leakage from layers that are prone to wear. There are various drawbacks such as the possibility that this may occur. A similar construction has free fiber ends in the area of the sliding surface of the shaft of the sealing ring, which fiber ends are oriented axially towards the medium to be sealed and are dependent on the direction of rotation of the shaft. A structure has been proposed in which the medium is deflected by the actuator, thereby causing the medium to be repelled. However, with this configuration, the seal ring is used in contact with the rotating body with elasticity that does not wear out (the seal ring tolerance is designed to be generous); Not only is there a risk of oil leakage, but when it is used as a general seal structure, the fiber ends wear out immediately, making it impossible to form proper directionality, resulting in a loss of sealing effect.

Furthermore, there has been proposed a structure in which the inner peripheral surface of the seal ring is lined with a canvas by slanting the texture. In this case as well, as in the case described above, the directionality is disturbed due to wear of the canvas and the sealing effect is lost, so there is a problem in durability.

Therefore, as a result of various studies in order to overcome all the problems of the conventional oil seals mentioned above, the inventor of the present invention found that the rubber or synthetic resin material that is the base material of the oil seal is a material known to have directionality. By mixing these unit materials and arranging them in a certain direction at a required angle with respect to the axial direction, a microscopic oil reverse flow path is formed at the sealing surface with the rotating shaft, It has been found that the sealing function and durability can be improved.

In addition, as the material having the above-mentioned directionality, for example, fibers such as glass fiber, carbon fiber, and heat-resistant synthetic fiber, or unit materials of fine particles such as mica, glassite, talc, and silica having directionality are preferably used. be able to.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an oil seal that has a simple structure, is easy to manufacture, has an improved sealing function for a high-speed rotating shaft, has excellent durability, and can reduce manufacturing costs. .

In order to achieve the above object, the present invention provides an oil seal that is provided with a seal lip that comes into contact with the outer peripheral surface of a rotating body to form a sealing surface, and that is configured to hold this seal lip in pressure contact with the rotating body. A directional substance is contained in the material constituting the seal lip, and most of the directional substance is oriented in a certain direction at a predetermined angle with the axial direction of the rotating body, and the sealing surface that contacts the rotating shaft of the seal lip is It is characterized in that it is configured to expose a portion of the directional substance and to increase the exposure of the directional substance as the sealing surface wears.

In the oil seal described above, it is preferable that the annular body including the seal lip be made of rubber or synthetic resin material. In this case, as the directional substance, a material selected from fibers such as glass fiber, carbon fiber, and heat-resistant synthetic fiber, or directional fine particles such as mica, graphite, talc, and silica can be suitably used. .

In addition, the orientation of the directional substance in the seal part is
It is preferable to set the flow path in the air region side so as to form a flow path that has an axial flow pumping effect that pushes back oil leaking from the oil region side by rotation of the rotary shaft.

Furthermore, the angle of inclination between the sealing surface of the directional material and the axial direction of the rotating shaft can be selected within a certain range of 5 to 175 degrees, particularly 20 to 60 degrees, 120 to 160 degrees.
It is preferable to set it within a range of .

Next, embodiments of the oil seal according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 2 shows a sectional view of an oil seal according to the present invention. In this embodiment, the shape of the oil seal is the same as a conventional general oil seal. That is, in FIG. 2, reference numeral 20 indicates an annular body made of an elastic material such as rubber, and a seal lip 24 that forms a sealing surface with the rotating shaft 22 is provided in a part of this annular body 20. A garter spring 26 is attached to the outer periphery of the seal lip 24 as necessary, and the annular body 2
0 is held by a metal cylindrical body 28.

However, in the present invention, the annular body 20 provided with the seal lip 24 that forms a sealing surface with the rotating shaft 22 contains a directional substance 30 so as to be inclined in a predetermined direction with respect to the axial direction at the seal portion. Features. As the directional substance 30 that can be used in this case, fibers such as glass fiber, carbon fiber, and heat-resistant synthetic fiber, or fine particles having directional properties such as mica, graphite, talc, and silica are suitable.

As mentioned above, in order to obtain the annular body 20 of a predetermined shape by arranging and containing the directional substances 30 in a certain direction in a base material such as rubber or synthetic resin, it is possible to easily manufacture the annular body 20 by the following method. can. In other words, when a sheet-like base material of a predetermined thickness is continuously manufactured using an extruder or the like, if a unit material of a directional substance is mixed into the base material in advance, when the base material is extruded into a sheet shape, The directional substances are contained in the base material in a state where they are aligned in a certain direction. Next, the sheet-like base material thus obtained is cut into a predetermined width while taking into consideration the direction of the directional material, joined into a ring shape, and press-molded using a die molding machine. In this case, the directional material can be oriented arbitrarily within a range of about 5 to 175 degrees with respect to the axial direction at the sealing surface with the rotating shaft.

The oil seal according to the present invention obtained in this way has an oil region on the upper side and an air region on the lower side in the illustrated example, and the seal portion of the seal lip has an oil seal oriented in a predetermined direction with respect to the axial direction. Since the directional material 30 is distributed at a constant density, even if the tip of the seal lip wears out, new directional material constantly appears on the contact surface of the seal with the shaft, and is oriented at a certain angle. As the shaft rotates, the axial flow pump action is always activated, providing excellent sealing performance. In other words, as the seal surface increases due to wear on the seal surface, the exposure of directional substances also increases, increasing the sealing effect and significantly improving durability compared to conventional oil seals or threaded oil seals. . In this case, microscopic observation of the sealing surface reveals that the directional substance 30 is attached to the rotating shaft 22 against wear of the base material such as rubber.
A branch flow path in a certain direction is formed at the sealing surface. Therefore, in the present invention, the orientation of the directional substance 30 is set in relation to the rotating shaft 22 in a direction that produces an axial flow pumping action that pushes back the oil leaking from the oil region of the sealing surface to the air region. . Note that in order to effectively realize such an axial flow pumping action, the angle of inclination of the directional material 30 with respect to the rotating shaft 22 can be selected within the range of 5 to 175 degrees, but functionally it is within the range of 20 to 175 degrees.
60°, preferably in the range of 120 to 160°.

As is clear from the examples described above, in the oil seal according to the present invention, a directional substance is contained in a certain direction during manufacturing of the base material constituting the oil seal, and the orientation of the directional substance is changed during molding. By tilting it with respect to the axial direction, the inside of the seal lip also contains a directional substance and is oriented.
Even when worn, the axial flow pumping action is constantly generated to reliably prevent oil leakage from the oil region.

Therefore, the oil seal according to the present invention is not only simple in structure but also easy to manufacture.
It can be mass-produced at extremely low cost, and is highly economical because it has improved durability and effectively prevents oil leakage.

Although preferred embodiments of the present invention have been described above, the present invention can not only be suitably applied to oil seals without garter springs, but also various design changes can be made without departing from the spirit of the present invention. Of course it can be done.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of a conventional oil seal, and FIG. 2 is a sectional view showing an embodiment of the oil seal according to the present invention. 20... Annular body, 22... Rotating body, 24... Seal lip, 26... Garter spring, 28...
...Metal cylindrical body, 30...Directional material.

Claims (1)

[Scope of Claims] 1. An oil seal comprising a seal lip that comes into contact with the outer circumferential surface of a rotating body to form a sealing surface, and configured to hold this seal lip in pressure contact with the rotating body, in which the material constituting the seal lip contains A directional substance is contained and most of the directional substance is oriented in a certain direction at a predetermined angle with the axial direction of the rotating body, so that one part of the directional substance is oriented in a certain direction at a predetermined angle with the axial direction of the rotating body, and one of the directional substances is 1. An oil seal characterized in that the oil seal is configured to expose a part of the oil seal and to increase exposure of a directional substance as the seal surface wears. 2. The oil seal according to claim 1, wherein the annular body including the seal lip is made of an elastic material such as rubber or synthetic resin. 3. In the oil seal according to claim 1 or 2, the directional substance is fibers such as glass fiber, carbon fiber, heat-resistant synthetic fiber, or directional mica, graphite, talc, or silica. Oil seals made of materials selected from fine particles such as. 4. In the oil seal according to any one of claims 1 to 3, the orientation of the directional substance in the seal portion is such that the orientation of the directional substance in the seal portion is such that the rotation of the rotating shaft on the air region side pushes back oil leaking from the oil region side. An oil seal that is oriented to form a flow path that acts as a flow pump. 5. The oil seal according to claim 4, wherein the angle of inclination of the seal portion of the directional material with respect to the axial direction of the rotating shaft is selected within a certain range of 5 to 175 degrees.