JP2551701Y2 - Oil seal ring for automatic transmission - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil seal ring for an automatic transmission of an automobile or the like.

[0002]

2. Description of the Related Art Generally, in an automatic transmission such as an automobile such as a torque converter or a hydraulic clutch, an oil seal ring for sealing hydraulic oil is attached at a key point. Such an oil seal ring is rotatable between a rotating shaft and a cylinder and is in sliding contact with them. Therefore, in order to increase the transmission efficiency of torque of the transmission, it is preferable to form the oil seal ring from a synthetic resin having a low friction coefficient and excellent wear resistance. In order to improve the friction characteristics of the above synthetic resin oil seal ring and further reduce the rotational torque,
The length of the substantially rectangular cross section of the ring in the radial direction (hereinafter referred to as the wall thickness of the ring) is set to a dimension necessary and sufficient to make close contact with the outer peripheral surface of the rotary shaft and the inner peripheral surface of the cylinder, and the ring having the rectangular cross section It is preferable to reduce the length of the cylinder in the axial direction (hereinafter referred to as the width of the ring) to reduce the contact area with the cylinder.

However, as exemplified in FIG. 1, this type of oil seal ring is formed by dividing one portion in a circumferential direction in a radial direction and elastically deforming the facing divided surfaces so as to be staggered. Because it is attached to the rotating shaft,
If the width and the thickness are too small, it is easy to be deformed by a small external force, and there is a problem that it cannot be inserted together with the rotating shaft into the cylinder.

[0004]

As described above, this invention has a limit in reducing the width and thickness of the synthetic resin oil seal ring in order to improve the torque transmission efficiency of the automatic transmission. Yes, that is, to solve the problem that the rotation torque cannot be sufficiently reduced with the width and thickness that can be inserted into the cylinder, and such an oil seal ring has the rigidity necessary for incorporation into the rotating shaft, Another object is to make it possible to sufficiently reduce the rotational torque.

[0005]

In order to solve the above-mentioned problems, in the present invention, in a synthetic resin oil seal ring which is radially divided at one location in the circumferential direction and has a substantially rectangular cross section, In the peripheral ridge portion, a circular curved surface chamfering at least 10% of the radial length or the axial length of the rectangular cross section is formed.

[0006]

In the oil seal ring for an automatic transmission according to the present invention, a circular curved surface for reducing the inner and outer peripheral areas is formed in a predetermined size on a peripheral ridge portion, so that the inner peripheral surface is formed with respect to the rotating shaft and The outer peripheral surface is in sliding contact with the cylinder in an airtight manner, and is rotatable. Rotation torque is sufficiently reduced, and the rigidity required when the cylinder is inserted is the thickness which is the radial length of the rectangular cross section of the ring. And the width, which is the axial length. The size of the above-mentioned circular curved surface chamfers at least 10% of the width and the thickness, respectively.
This is because if this value is less than 10%, the rotational torque cannot be sufficiently reduced, and the original purpose cannot be achieved as an oil seal ring for an automatic transmission.

[0007]

An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the embodiment is made of a material containing ethylene tetrafluoride resin as a main material and carbon graphite as a filler. Width 1.9mm, Ring thickness 1.6
It is formed by molding an oil seal ring A of mm. In this case, as a molding method, extrusion molding, injection molding and other appropriate methods can be adopted. This oil seal ring A
Can be divided in the radial direction at one location in the circumferential direction, and can be deformed so that the divided surfaces a facing each other are staggered.

As shown in FIG. 2, an oil seal ring A
21% and 25% of the radial length (ring thickness) T or the axial length (ring width) W of the rectangular cross-section on the four peripheral ridges 1 on the inner and outer peripheral sides, respectively. , W are formed with an appropriate curvature. As a method for forming such a curved surface, barrel polishing (tumbling), shot blasting, cutting, molding with an injection mold, or the like may be used.

[0010]

[Table 1]

The oil seal ring A thus obtained (each dimension is shown in Table 1) was subjected to the following rotational torque test.

Rotational torque test: In a rotational torque tester shown in FIG.
The oil seal ring A is elastically deformed and mounted in the two ring-shaped grooves 3 of the rotary shaft 2 formed by the above. The rotary shaft 2 is rotated by the motor 5 via the rotary torque meter 4, and the cylinder made of cast iron (FC25) The oil seal ring A was brought into sliding contact with the inner diameter surface of No. 6. At this time, an oil supply pipe 7 from a hydraulic pressure generator (not shown) is connected to the upper part of the cylinder 6, and the hydraulic pressure (kgf /
cm ²⁾ was measured. A discharge pipe 9 for discharging the leaked oil was provided below the cylinder 6, and the oil temperature was measured with a thermocouple 10. The measurement conditions were as follows, using transmission oil for automobiles (Dexilon II manufactured by Showa Shell Sekiyu KK).
Hydraulic pressure ² , 4, 6, 10, 15 kgf / cm ² , shaft rotation speed 20
00 rpm and the oil temperature was 80 ° C. The results obtained are shown in the graph of FIG.

Comparative Examples 1 to 3 Comparative Examples 1 and 2 in which a molding material having the same composition as that of the example was used, and the dimensions shown in Table 1 were not formed on the peripheral ridge portion, or the size of the circular curved surface was the same as that of the ring. The oil seal ring of Comparative Example 3 having less than 10% of the wall thickness or the width of the ring was molded, and the rotational torque was measured in the above-described rotational torque tester under exactly the same conditions as in the example. Also shown in the graph.

As is clear from the measured values of the rotational torque for each oil pressure in the graph of FIG. 4, the comparative examples 1 and 2 in which no circular curved surface was formed on the peripheral ridge and the size occupied by the circular curved surface were as follows:
In Comparative Example 3 each having less than 10% of the wall thickness or width of the rectangular cross section of the ring, the rotation torque increased at a very large rate with an increase in hydraulic pressure, whereas Example 1 increased at a very small rate. .

[0015]

[Effect] As described above, the oil seal ring for an automatic transmission according to the present invention does not reduce the rigidity required when installing the oil seal ring made of synthetic resin.
It is possible to sufficiently reduce the rotational torque of the rotary shaft to which this is attached. Therefore, in an automatic transmission equipped with such an oil seal ring, high transmission efficiency can be obtained with low torque, and it can be said that the industrial utility of the present invention is high.

[Brief description of the drawings]

FIG. 1 is a front view of an embodiment.

FIG. 2 is a longitudinal sectional view of the same.

FIG. 3 is a longitudinal sectional view of a rotational torque tester.

FIG. 4 is a graph showing a relationship between hydraulic pressure and rotational torque.

[Explanation of symbols]

 A Oil seal ring a Dividing surface 1 Circumference

Claims (1)

(57) [Scope of request for utility model registration] Claims: 1. A part is divided radially at one location in a circumferential direction,
In a synthetic resin oil seal ring having a substantially rectangular cross section, a circular curved surface chamfering at least 10% of a radial length or an axial length of the rectangular cross section is formed on a peripheral ridge of the ring. Characteristic oil seal ring for automatic transmission.