JPS6123717Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a seal structure for various fluid devices,
In particular, a seal ring mainly made of tetrafluoroethylene resin (trade name, Teflon) is housed in the outer circumferential groove of the rotating member that rotates within the inner hole of the housing, and the seal ring connects the inner circumferential wall of the inner hole to the rotating member. This invention relates to an improvement in a seal structure that seals between the outer circumferential surfaces of.

Conventionally, for example, in a rotary valve used in a rack-and-pinion power steering device, the first
As shown in the figure, seal rings 13 are housed in the respective outer circumferential grooves 12a of the cylindrical valve body 12 that rotates within the inner hole 11 of the housing 10, and the seal rings 13 allow the flow to flow out from the inlet hole 10a. hole 10
This prevents leakage of the pressure oil that selectively flows to ports b and 10c. In this case, the housing 10 is generally made of a soft metal such as aluminum, while the cylindrical valve body 12 is made of a hard metal such as iron, so the seal ring 13 is made of tetrafluoroethylene resin containing glass fiber. When adopted, the inner wall surface of the inner hole 11 is worn out due to the rotation of the valve body 12,
Stepped wear D as shown in FIG. 2 occurs. This causes problems such as the sealing performance of the seal ring 13 deteriorating and the rotational frictional force increasing. To deal with such problems,
Changing the material of the housing 10 to hard metal,
Forming an alumina layer on the inner peripheral wall surface of the inner hole 11,
Alternatively, countermeasures such as casting an iron liner can be considered, but these countermeasures increase production costs and cause an increase in weight, so they are not a good idea.

The present invention was devised focusing on the above-mentioned problem, and its gist is that either the housing or the rotary member that rotates within its inner hole is made of a soft metal such as aluminum. and the other member is made of a hard metal such as iron,
A seal comprising a seal ring mainly made of tetrafluoroethylene resin is housed in an outer circumferential groove of the rotating member, and the seal ring seals between the inner circumferential wall of the inner hole of the housing and the outer circumferential surface of the rotating member. The structure is characterized in that a seal member such as synthetic rubber having a larger coefficient of friction than the seal ring is attached to the contact surface of the seal ring with the one member. That is, in the present invention, when the housing is made of a soft metal and the rotating member such as a cylindrical valve body that rotates in the inner hole is made of a hard metal, a seal is provided on the contact surface of the seal ring against the inner circumferential wall of the inner hole. A seal member with a larger coefficient of friction than the ring is attached to allow relative rotation only between the seal ring and the rotating member, and if the housing is made of hard metal and the rotating member is made of soft metal, rotation is prevented. A seal member having a larger friction coefficient than the seal ring is attached to the contact surface of the seal ring with respect to the member, so that relative rotation is allowed only between the seal ring and the inner circumferential wall of the inner hole.

Embodiments of the present invention will be described below with reference to the drawings. In FIG. The members are shown, and numeral 23 indicates a seal ring molded from tetrafluoroethylene resin containing glass fibers. A feature of this embodiment is that a synthetic rubber sealing member 24, which has a larger coefficient of friction than the sealing ring, is integrally attached to the outer peripheral surface of the sealing ring 23 by baking. The seal ring 23 is inserted into the outer circumferential groove 22a of the rotating member 22 when pressure oil is applied from the direction of the arrow shown in the figure.
When the rotary member 22 rotates in this state, the seal ring 23 is pressed against the inner circumferential wall of the inner hole 21 and the side end surface of the outer circumferential groove 22a.
It is fixed to the inner circumferential wall side of the inner hole 21 by the frictional force of , and makes relative sliding contact only with the rotating member 22 . Therefore, the housing 20 is protected from wear even if there is a soft metal, and the seal ring 23 properly exhibits its sealing performance through sliding contact with the rotating member 22 made of hard metal.

FIG. 4 shows an embodiment in which the housing 20 shown in FIG. 3 is made of iron and the rotating member 22 is made of aluminum. Its characteristic lies in that the synthetic rubber sealing member 24a, which has a large coefficient of friction, is integrally fixed by baking, and as a result, the sealing ring 23 is rotated by the rotating member 22' when pressure oil is applied from the direction of the arrow in the figure. When it rotates, it rotates together with the rotary member 22' due to the frictional force of the seal member 24a. Therefore, even if the rotating member 22' is made of a soft metal, it is protected from wear, and the seal ring 23 exhibits its sealing performance by slidingly contacting the inner peripheral wall surface of the housing 20' made of a hard metal.

In each of the above embodiments, an example was explained in which pressure oil acts only from one direction on the seal ring 23. However, for example, when the housing 20 is made of aluminum and the rotating member 22 is made of iron, the case shown in FIG. As shown above, the seal rings 23b, 23b made of tetrafluoroethylene resin are adhered to both sides of the annular synthetic rubber seal member 24b, and the seal member 24b is sealed into the housing inner hole 2 by the action of pressure oil.
1, and one of the seal rings 23b may form a sliding surface that slides against one end surface of the outer circumferential groove 22a of the rotating member 22, or as shown in FIG. A synthetic rubber O is attached to the outer periphery of the tetrafluoroethylene resin seal ring 23c.
The ring 25 is fitted and the O-ring 25 is pressed against the inner peripheral wall surface of the housing inner hole 21 by the action of pressure oil, so that one side surface of the seal ring 23c slides against one end surface of the outer peripheral groove 22a of the rotating member 22. A contacting sliding surface may also be formed.

As detailed above, according to the present invention, when the housing is made of a soft metal and the rotating member such as a cylindrical body that rotates in the inner hole is made of a hard metal, the A seal member with a larger friction coefficient than the seal ring is attached to the contact surface of the seal ring made of ethylene chloride resin, allowing relative rotation only between the seal ring and the rotating member, and the housing is made of soft metal. When the rotating member is made of soft metal, a sealing member with a larger friction coefficient than the seal ring is attached to the contact surface of the seal ring with the rotating member, so that there is only a gap between the seal ring and the inner circumferential wall of the inner hole. This allows rotation of the rotary member made of soft metal by the seal ring, thereby preventing deterioration of sealing performance in the area, and preventing other seal surfaces from being damaged by worn metal powder. It is possible to eliminate adverse effects on parts such as sliding surfaces and orifices. Furthermore, according to the above configuration, the sealing performance is improved by using a sealing member with a large coefficient of friction, the blow-through phenomenon that often occurs with seal rings can be prevented to a minimum, and the sealing surface by the seal ring is in one place. Therefore, deterioration of sealing performance at low temperatures of 0° C. or lower can be suppressed as much as possible.

In the former case, in particular, the sliding surface of the seal ring is located inside the inner wall of the housing, and the radius of friction becomes smaller accordingly, making it possible to reduce rotational wear force.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an example of a rotary valve to which the present invention is applied, Fig. 2 is a partial sectional view showing a conventional seal structure, and Figs. 3 to 6 are parts showing each embodiment of the present invention. FIG. Explanation of symbols, 20...Housing made of soft metal, 20'...Housing made of hard metal,
21... Inner hole, 22... Rotating member made of hard metal, 22'... Rotating member made of soft metal, 23
...Seal ring mainly made of tetrafluoroethylene resin, 24...Synthetic rubber seal member.

Claims (1)

[Scope of utility model registration request] One of the housing and the rotary member that rotates in its inner hole is made of a soft metal such as aluminum, and the other member is made of a hard metal such as iron, and the outer circumferential groove of the rotary member is A sealing structure in which a sealing ring mainly made of tetrafluoroethylene resin is housed in the housing, and the sealing ring seals between the inner circumferential wall of the housing inner hole and the outer circumferential surface of the rotating member, wherein the one of the sealing rings A seal structure characterized in that a seal member such as synthetic rubber having a larger coefficient of friction than the seal ring is attached to the contact surface with the member.