JPS6229722Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a sealing device.

Conventionally, sealing devices such as those illustrated in FIGS. 1 and 2 have been used. That is, an elastic support ring b such as an O-ring and a ring c having a straight-letter cross section are fitted into the groove a to seal the gap f between the first member d and the second member e. . Second member e
Since the ring c is in full flat contact with the surface of the ring, the sealing performance at low pressure is poor, and
When the high pressure P is applied as shown in Fig. 2, the ring c and the second member e
The contact surface pressure p with the second
The liquid film adhering to the surface of the member e passed through the ring c and the second member e as they slid, and the sealing performance at high pressure was also unsatisfactory.
Particularly when the second member e is a piston rod and the first member d is a cylinder head cover, etc., the liquid film that has adhered to the piston rod and has passed to the outside can be scraped with a scraper (not shown) or the like. There were drawbacks such as dripping and dripping to the outside. Furthermore, as a prior art, the invention described in Japanese Patent Publication No. 52-5663 is known, however, the following drawbacks remain in this case as well. That is, the contact sliding area is large, the contact is flat, and the sealing performance at low pressure is poor.The distribution of contact surface pressure is a gentle mountain shape in the middle part as shown in Figure 2, and in the left and right parts. Since it is not affected by the elastic force of the O-ring, the contact pressure at low pressures is almost zero, and the disadvantage is that a thin liquid film passes through it as a whole (liquid film cannot be scraped off). The long single-letter-shaped sealing ring receives high pressure on the back side (because the pressure-receiving area is too large), resulting in a significantly excessive sliding resistance.Machining of the concave groove is troublesome, and the sealing space is large. It had many drawbacks such as:

The object of the present invention is to eliminate these conventional drawbacks and provide a sealing device that can always provide stable and good sealing performance from low to high pressures.

Hereinafter, the present invention will be explained in detail based on the illustrated embodiments.

In FIGS. 3 and 9, 1 is a first member having an annular groove 2, and 3 is a second member. For example, the first member 1 is a head cover portion of a hydraulic cylinder,
The second member 3 corresponds to a piston rod, or the first member 1 corresponds to a piston of a cylinder and the second member 3 corresponds to a cylinder tube.

Reference numeral 4 designates an elastic support ring that is fitted into the inner part of the groove 2, and specifically has a circular cross section and is made of various relatively soft rubber materials.

Reference numeral 5 denotes a sealing ring made of hard resin that is pressed toward the opening side of the groove 2 by the support ring 4 and comes into sealing contact with the peripheral surface 3a of the second member 3. For example, tetrafluoroethylene resin or the like is used.

Thus, in the cross-sectional shape of the sealing ring 5, the side of the pressing surface 6 with which the support ring 4 comes into elastic contact forms one straight side, and the sides of the front and rear end surfaces 7 and 8 also form straight sides. However, in the sealing surface 9 corresponding to the circumferential surface 3a of the second member 3, there is a central protrusion 11 whose top portion 10 is rounded at approximately the center in the direction of the axis A.
Further, near the edges in the axial direction, edge protrusions 12 and 13 in the shape of acute triangular ridges are formed. Specifically, the corners of the front and rear end surfaces 7, 8 and the sealing surfaces 7, 8 are formed into triangular chevron-shaped edge protrusions 1.
2 and 13, and together with the central protrusion 11, the three annular contact portions contact the circumferential surface 3a of the second member 3 in a sealed manner.

The curved direction is reversed at the hem of the central protrusion 11, and the shape is connected to the edge protrusions 12 and 13 at a gentle slope, and the central protrusion 11 and the edge protrusion 1
Concave circumferential grooves 14 and 15 are formed between the second member 3 and the circumferential surface 3a of the second member 3, and as shown in FIG. be done.

FIG. 9 shows a case where the sealing device is fitted and no fluid pressure is applied or the fluid pressure is extremely low. The contact pressure p applied to the circumferential surface 3a of FIG. , it can be seen that the elastic support ring 4 is collapsed and elastically presses the sealing ring 5 in the radial direction as indicated by the arrow r.

Next, FIG. 10 illustrates a case where high pressure P is applied from the right side of the figure, and the soft elastic support ring 4 is pressed to the left side of the figure, and the sealing ring radially moves as indicated by arrow R. 5, the fluid pressure P is combined with the action on the sealing support ring 5 itself, resulting in a distribution of contact surface pressure p as shown in the figure. It can be seen that the central protrusion 11 and the edge protrusion 12 on the low pressure side are extremely strongly pressed against the circumferential surface 3a of the second member 3 and perform a sealing action as a sealing lip.

Next, in another embodiment shown in FIG. 4, the top portion 10 of the central protrusion 11 is formed into a narrow flat shape, and other than that, the structure is almost the same as that of the previous embodiment. Further, FIGS. 5 and 6 show other embodiments corresponding to FIGS. 3 and 4, respectively, in which the edge protrusion 12,
13 is the central protrusion 1 slightly inside the front and rear end surfaces 7 and 8.
Relief portions 16 and 17 are formed in the shape of notches at the corners of the end surfaces 7 and 8 and the sealing surface 9. When the first member 1 and the second member 3 slide relative to each other, the corner portions are prevented from getting caught in the mutual gap and being torn off.

Next, FIGS. 7 and 8 show other embodiments corresponding to FIGS. 5 and 6, respectively, in which one relief part 16 has a triangular cross section and a tapered chamfered shape. As a result, one edge protrusion 12 forms an obtuse triangular chevron. When one edge protrusion 12 has an obtuse angle as described above, it is suitable for use as a piston rod of a hydraulic cylinder. That is, the second
The member 3 is a piston rod, and FIGS. 7 and 8
If the device is installed with the left side of the figure as the outside (low pressure side), a thin liquid film will adhere to the circumferential surface of the piston rod and pass to the outside, and then the piston rod will be exposed to arrow E.
During shortening movement in the direction, the edge protrusion 12 will not scrape off the edge protrusion 12.
This has the advantage of preventing problems such as liquid gradually accumulating outside (left side of the figure) and dripping outside.

In the above examples and FIG. 11, the elastic support ring 4 is a so-called O-ring with a circular cross section. It is also free to have a cross-sectional shape cut along the minor axis. Further, as shown in FIG. 12, it is preferable to form a shallow groove 18 on the pressing surface 6 of the sealing ring 5.

The present invention has effectively achieved its intended purpose with the configuration detailed above. In particular, a top rounded or flat central protrusion is formed approximately at the center of the sealing surface of the sealing ring, and a triangular chevron-shaped end protrusion is formed near the axial end edge, and three annular protrusions are formed. Since the abutment part forms a seal, not only does it have excellent sealing performance at low pressures, but also extremely excellent sealing performance can be stably obtained as a sealing device for high pressures of around 250 kg/cm ² . In other words, the three annular contact portions are in close contact with the second member 3 with different contact surface pressure distributions, and can handle all pressures from low pressure to high pressure, and the sealing ring does not fall down in the groove and maintains a stable posture. hold it. Even if one lip is damaged, the other two serve to compensate, and the concave circumferential groove also serves as a labyrinth groove. Moreover, the sliding friction resistance with the second member is also small. In particular, when compared with the conventional invention disclosed in Japanese Patent Publication No. 52-5663, the following remarkable effects are achieved. The contact sliding area with the second member 3 is considerably smaller than the width dimension of the groove 2,
As shown in FIG. 9, since the three annular contact portions contact the sharp, the sealing performance at low pressure is excellent. The edge protrusions 12 and 13 near the edge of the sealing ring 5 are 3
The sealing ring 5 has a square chevron shape, and the width of the sealing ring 5 (slightly smaller than the width of the groove) is approximately equal to that of the internal elastic support ring 4 (as shown in FIGS. 9 and 10).
As shown in the figure), the elastic support ring 4 can effectively receive the elastic force and the pressing force due to the receiving pressure, and can exhibit excellent sealing performance both under low pressure and high pressure. When the pressure is high, the pressure within the width of the groove 2 acts on the sealing ring 5 as shown in FIG. 10, so that the pressure-receiving area does not become excessive and the sliding resistance is small. The concave groove 2 does not require step machining, and machining is easy and the sealing portion can be made compact. Thus, it can be said that the practical effects of the present invention are significant.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a conventional example, and FIG. 2 is a high-pressure operating state, which is a cross-sectional view and a pressure distribution diagram. Fig. 3 is a sectional view showing one embodiment of the present invention, Figs. 4, 5, 6, 7, and 8 are sectional views showing different embodiments, and Fig. 9 is a low pressure 10 shows the state of use at high pressure, is a sectional view, is a pressure distribution diagram, and FIG. 11 is a simplified sectional view of the elastic support ring. FIG. 12 is a sectional view showing yet another embodiment. DESCRIPTION OF SYMBOLS 1... First member, 2... Concave groove, 3... Second member, 4... Elastic support ring, 5... Sealing ring,
9... Sealing surface, 10... Top, 11... Center protrusion, 12, 13... Edge protrusion, 14, 15... Concave circumferential groove, 3a... Circumferential surface.

Claims (1)

[Scope of utility model registration request] An elastic support ring that is fitted into the deep part of the groove of a first member having a groove, and an elastic support ring that is pressed toward the opening side of the groove by the support ring and is sealed against the circumferential surface of the second member. The sealing device includes a sealing ring made of hard resin that is in contact with the groove, and the cross-sectional shape of the groove is formed into a substantially rectangular shape, and the width of the elastic support ring and the width of the sealing ring are set so that the width of the groove is substantially rectangular. It is set slightly smaller than the width dimension, and furthermore, on the sealing surface of the sealing ring, approximately at the center in the axial direction,
A central protrusion is formed with a rounded or flat top in contact with the circumferential surface of the second member, and a triangular chevron-shaped top in contact with the circumferential surface of the second member is formed near the edge in the axial direction. An edge protrusion is formed,
A concave circumferential groove is formed between the central protrusion and the edge protrusions, and three annular contact portions of the central protrusion and the left and right end edge protrusions contact the circumferential surface of the second member. A sealing device configured to contact in a sealed manner at.