JPH08145186A - Seal device - Google Patents

Abstract

PURPOSE: To provide a seal device Which leads working fluid to a main seal at low pressures at which any damage does not occur on the main seal so as to maintain the performance by lubricating seal members of the main seal, and operates, at high pressures, without transmitting high pressure and impact pressure of working fluid to the main seal. CONSTITUTION: A protective seal device 6 to seal working fluid is provided with a seal ring, a pressing 12 to provide a contact pressure to a seal ring 11 and a seal ring 11, and an energizing ring 13 to engage with the pressing ring 12. Also the seal ring 11 is provided with a first sliding surface 11a, a second sliding surface 11b, and a flow path 11c on the sliding surface 11b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal device, and more particularly to a seal device incorporated in a seal portion of a cylinder member and a piston member.

[0002]

2. Description of the Related Art A conventional hydraulic cylinder 10 as shown in FIG.
In Fig. 1, a piston 103 fixed to a rod 104 is slidably inserted into a cylinder inner hole 102, and the rod 104 is indicated by an arrow A1 'by sucking and discharging a working fluid into the pressure chamber 102a or 102b. It moves to the left and right.

FIG. 10 shows the rod cover 105 shown in FIG.
FIG. 3 is an explanatory view of a main part of a D1 part of FIG. In FIG. 10, the left side in the figure is the hydraulic pressure side and the right side is the atmospheric pressure side.
In order to seal the gap between the rod 5 and the rod 104, the following sealing structure is adopted. That is, a protection seal device 106 that protects the main seal from high pressure and impact pressure of the working fluid in order from the hydraulic side, a main seal 107 that mainly seals the working fluid so as not to leak from the gap between the rod cover 105 and the rod 104, and a rod. The rod cover 105 is provided with a dust seal 108 that protects the main seal 107 from the dust on the atmosphere side attached to 104.

FIG. 11 is an enlarged view of a main part of the protective seal device 106. The protection seal device 106 is the rod cover 105.
And a seal ring 106a made of a resin material fitted in an annular groove 105a provided in the
And the pressing ring 106b fitted in the annular groove 105a and applying a close pressure to the seal ring 106a, as described above, protects the main seal from the high pressure and impact pressure of the working fluid.

[0005]

However, in such a conventional example, the seal ring 106a is always in close contact with the rod 104 by the pressing ring 106b,
Since the sealing performance of the protective sealing device 106 is too good, the following problems occur.

That is, because the sealing performance is too good,
The oil film supplied to the main seal 107 is reduced, the seal portion of the main seal 107 is in a dry state, the friction of the contact portion (seal portion) with the rod 104 is increased, and excessive wear of the seal portion occurs, resulting in sealing performance. And shorten the life.

As a countermeasure against the above, the seal ring 10 shown in FIG. 12 (a) and its S1S1 sectional view (b) is shown.
No. 6c does not have a tightening ring in order to improve lubricity, and a working fluid passage hole 106d is provided on the sealing surface with the rod 104. However, since there is no tightening ring, the sealing property of the seal ring 106c is reduced. Becomes unstable, the high pressure and impact pressure of the working fluid are transmitted to the main seal, and the main seal is damaged.

The present invention has been made to solve the above-mentioned problems of the prior art. The purpose of the present invention is to guide the working fluid to the main seal at a low pressure when the main seal is not damaged, and It is an object of the present invention to provide a seal device which lubricates a seal member to maintain its performance and which operates at high pressure without transmitting high pressure and impact pressure of a working fluid to a main seal.

[0009]

In order to achieve the above object, in the present invention, an annular groove formed in an opposing peripheral surface of either one of a cylinder member and a piston member that are fitted relative to each other, In a sealing device in which a seal ring that closely slides on the sliding surface of the other member and a pressing ring that applies a close pressure to the seal ring are fitted and inserted, the seal ring is in sliding contact with the other member at high pressure. One sliding surface, a second sliding surface inclined from the first sliding surface at a predetermined angle and in sliding contact with the other member at low pressure, and the other sliding surface when the second sliding surface has low pressure. And a flow path that allows fluid to communicate in the axial direction while being in sliding contact with the member.

Further, it is fitted into an annular groove formed in the seal ring, and in a direction in which the first sliding surface is brought into contact with and separated from the sliding surface of the other member by a predetermined pressing force by a spring force. It is also preferable to provide a biasing ring for biasing.

The pressing ring applies a close pressure to the first sliding surface when the pressure is high and a close pressure is applied to the second sliding surface when the pressure is low. It is also preferable to be configured to be movable to the second position.

The sealing device is provided upstream (on the pressure side) of the main seal that seals between the members that move relatively.

When the first sliding surface is in close contact with the sliding member, the working fluid is sealed against the pressure and impact pressure of the working fluid.

[0014]

In the sealing device of the present invention constructed as described above, the sliding surface is switched by the pressure of the working fluid acting on the sealing device. When the pressure is low, the second sliding surface seals the member. In this state, the flow path that is in sliding contact with the sliding surface and that allows fluid to communicate in the axial direction provided in the seal ring allows the working fluid to communicate.

When the working fluid acting on the sealing device has a high pressure, the first sliding surface makes sliding contact with the sliding surface of the sealing member to seal the working fluid against the pressure and impact pressure of the working fluid. To do.

The urging ring fitted in the concave groove formed in the seal ring separates the first sliding surface from the sliding surface of the other member with a predetermined pressing force by the spring force. Energize in the direction of contact.

Further, the pressing ring is acted on by the pressure of the working fluid, and on the seal ring, the second ring when the pressure is low.
From the second position where the close contact pressure is applied to the sliding surface to the first position where the close contact pressure is applied to the first sliding surface at high pressure.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments.

(First Embodiment) FIG. 1 is an explanatory view of a hydraulic cylinder 1 to which a sealing device 6 of the present invention is applied. In the hydraulic cylinder 1, a piston 3 fixed to a rod 4 is provided in a cylinder inner hole 2. It is slidably inserted, and the rod 4 moves in the left and right directions as shown by an arrow A1 by sucking and discharging the working fluid into the pressure chamber 2a or 2b.

FIG. 2 shows D2 of the rod cover 5 in FIG.
It is a principal part explanatory drawing of a part. In FIG. 2, the left side in the figure is the hydraulic pressure side, and the right side is the atmospheric pressure side.
The following sealing structure is used to seal the gap. That is, a protective seal device 6 as a seal device of the present invention that protects the main seal from high pressure and impact pressure of the working fluid in order from the hydraulic side, and seals the working fluid L from leaking from the gap between the rod cover 5 and the rod 4. The rod cover 5 is provided with a main seal 7 and a dust seal 8 that protects the main seal 7 from dust on the atmosphere attached to the rod 4.

FIG. 3 is an enlarged view of a main part of the protective seal device 6. As shown in FIG. 3A, the protective seal device 6 includes a seal ring 11 fitted in an annular groove 5 a provided in the rod cover 5, a pressing ring 12, and a seal ring 11.
And a biasing ring 13 fitted into an annular recessed groove 11d provided on the first sliding surface 11a.

The protective seal device 6 will be described in detail with reference to FIG. 3 (b). The seal ring 11 is made of elastic metal or a highly elastic resin material, and the sliding surface of the seal ring 11 has a load pressure of the working fluid. The first sliding surface 11a forming one axial end of the rod 4
And the other axial end of the rod 4 is notched in a tapered shape to
The second sliding surface 11b inclined at a predetermined angle from the sliding surface 11a and the second sliding surface 11b of the seal ring 11 slidably and closely contact the rod 4 with the working fluid L. It is provided with a plurality of flow paths 11c that can be conducted and an annular groove 11d into which the biasing ring 13 is inserted.

The pressing ring 12 is fitted with the seal ring 11 to apply a close pressure to the sliding surface of the seal ring 11, and its axial length 12l is the axial length of the seal ring 11 in this embodiment. A second position which is shorter than 11 l and applies a close pressure to the second sliding surface when the working fluid L has a low pressure,
At a high pressure, it can be moved to a first position on the seal ring that applies a close pressure to the first sliding surface.

The biasing ring 13 is fitted into an annular groove 11d formed in the first sliding surface 11a, and has a spring force capable of deforming according to the state of the first sliding surface 11a. Alternatively, the first sliding surface 11a is made of a highly elastic resin material and is biased in a direction of an arrow A2 that separates and contacts the first sliding surface 11a from the rod 4 with a predetermined pressing force, and slides on the second sliding surface 11b. It is urged in the direction of arrow A3 to be brought into close contact with the rod 4, which is a member for As shown in FIG. 4A, the urging ring 13 is an annular member that is cut at one place by the cut portion 13a, and the inner diameter Φd ₁ that closely contacts the surface of the rod 4 when free Outer diameter Φd ₀ and Φd ₁ > Φ
The relationship of d ₀ is established, and when the cut portion 13a is closed, it closely contacts the surface of the rod 4 and Φd ₂ = Φd ₀ . (Φd
₂ is the inner diameter of the biasing ring 13 with the cut portion 13a closed. ) FIG. 4 (b) shows the cut portion 13 of the biasing ring 13 '.
In this example, a'is cut obliquely.

In the present embodiment, the shape of the biasing ring 13 is illustrated as a quadrangle, but the shape is not limited to this and may be any shape such as a round shape, a trapezoidal shape, a triangular shape or a hexagonal shape.

Further, the position of the annular recessed groove 11d is not limited to the end portion of the first sliding surface 11a, but may be provided at any position on the first sliding surface 11a. Further, the annular recessed groove 11d may be positioned on the opposite surface on the second sliding surface 11b side, and the biasing ring 13 may bias the seal ring 11 in the direction in which the seal ring 11 is pressed against the rod 4. In this case, the annular groove 11d is not provided in the first sliding surface 11a that is in close contact at high pressure, the area of the sliding surface 11a is not reduced, and the biasing ring 13 and the rod 4 are Since it does not come into direct contact, scratches can be prevented.

As shown in FIGS. 1 and 2, the protective seal device 6 having the above-described structure has the rod cover 5 of the hydraulic cylinder 1.
Of the plurality of annular grooves formed on the inner peripheral surface of the working fluid L
Is fitted in the annular groove 5a on the hydraulic pressure side and functions as a primary seal portion for sealing the working fluid flowing in from the left side in the drawing. As described, the main seal 7 and the dust seal 8 are fitted in each. FIG. 5A shows an operating state of the protective seal device 6 when the working fluid L has a low pressure. The urging ring 13 is the first sliding surface 11 a of the seal ring 11.
Is urged in a direction in which it is separated from and contacted with the rod 4 by a predetermined pressing force, and in a direction in which the second sliding surface 11b is brought into close contact with a sliding member. Close to. The pressing ring 12 bends due to the urging force of the urging ring 13, or the second sliding surface 1 on the seal ring 11 is bent.
It has moved to a second position that applies close pressure to 1b. In this state, the working fluid L (thick solid black solid line) passes through the flow path 11c provided on the second sliding surface 11b, and passes through the protective seal device 6
In this state where the working fluid L reaches the main seal 7, the working fluid L is sealed by the main seal 7, but since there is no pressure or impact pressure, the main seal 7 is not damaged and the lubricating action Is applied to reduce the friction of the contact portion (sealing portion) of the main seal 7 with the rod 104, prevent wear of the sealing portion, and improve the sealing performance and life.

The tightening ring 12 is mainly intended to apply a close contact pressure to the seal ring 11, but when the seal ring 11 has the first sliding surface 11a in close contact with the rod 4, the annular groove 5a. Since the width of the gap between the upper end surface of the seal ring 11 and the seal ring 11 is small, and a large contact pressure can be applied due to a large elastic deformation in the diametrical direction of the cross section by the pressure, similar to the conventional structure shown in FIG. A sealing effect can be achieved. FIG. 5B shows an operating state of the protective seal device 6 when the working fluid L is at a high pressure. The working fluid L applies a fluid pressure to the sealing device 6 from the left direction in the figure as shown by an arrow A4. . Pressing ring 12
Is pushed by the fluid pressure in the direction of arrow A5, and the seal ring 11 in FIG. 5 (a) seals against the urging force of the urging ring 13 from the state in which the second sliding surface 11b is in close contact with the rod 4. The ring 11 switches the first sliding surface 11a to the state in which the first sliding surface 11a is in close contact with the rod 4. In this state, the working fluid L
Since the seal ring 11 is reliably sealed by the first sliding surface 11a and pressure or impact pressure is not transmitted to the main seal 7, the main seal 7 is not damaged.

In the above description, the sliding surface of the seal ring 11 is switched to the state where the first sliding surface 11a and the second sliding surface 11b are in complete contact with the rod 4, respectively.
As shown in (a) and (b), when the working fluid L has a low pressure, the first sliding surface 11a and the second sliding surface 11b are slanted slightly with the corners 11e of the sliding surfaces 11a as fulcrums. Since the moving surface has been switched, the working fluid L flows through the flow path 11 as indicated by an arrow A6.
It is possible to achieve the object of the present invention even if the sliding surface is not completely switched by flowing through c to the main seal 7 direction, and this is also included in the scope of the present invention.

(Second Embodiment) FIG. 7 shows a second embodiment of the present invention. 21 is the seal ring 1 in the first embodiment.
This is equivalent to 1. In the present embodiment, when the second sliding surface 21b comes into close contact with the rod 4 when the pressure is low, the flow passage 21c that allows the working fluid L to communicate with the main seal side has a predetermined dimension from the second sliding surface 21b. It is provided separately in the seal ring 21.

This flow path 21c is used for the second sliding surface 2 when the pressure is low.
When 1b is in close contact with the rod 4, the working fluid is allowed to communicate from the end surface of the seal ring 21 on the second sliding surface 21b side to the first sliding surface 21a side.

(Third Embodiment) FIGS. 8A and 8B show a third embodiment of the present invention. Reference numeral 31 corresponds to the seal ring 11 in the first embodiment.

In this embodiment, the seal ring 31 is not provided with a biasing ring and an annular groove into which the biasing ring is fitted.

However, the shape of the seal ring 31 is such that, in the free state, the first sliding surface 31a is inclined from the shaft 31z so that the seal ring 31 itself is urged by the urging ring. There is.

FIG. 8B shows a state in which the seal ring 31 is attached at a low pressure. If the pressure of the working fluid is low, the second sliding surface 31b is brought into close contact with the rod 4.
31c is a flow path. Here, when the pressure of the working fluid L increases, the pressing ring 12 is pressed in the direction of arrow A7, and the pressing ring 12 presses the surface of the seal ring 31 that faces the first sliding surface 31a. The sliding surface 31 a of No. 1 comes into close contact with the rod 4.

When the pressure of the working fluid L decreases, the first sliding surface 31a is separated from the close contact surface with the rod 4 by the shape restoring force of the seal ring 31 to return to the original free shape.
It returns to the state of FIG.8 (b).

The effect of this embodiment is that an urging ring is not required, the cost can be reduced, and an annular groove is provided on the first sliding surface 31a, which is in close contact with a high pressure. Therefore, the area of the sliding surface 31a does not become small, and
Since the biasing ring and the rod 4 do not come into direct contact with each other, scratches can be prevented.

[0038]

The present invention has the above-described structure and operation. When the working fluid working in the sealing device of the present invention has a low pressure, the second sliding surface is in close contact with the sliding surface of the other member, When the pressure of the working fluid is high, the first sliding surface comes into close contact with the sliding surface of the other member, so that when the working pressure is low, the working fluid flows through the flow path provided in the second sliding surface. Communicate with the sealing device,
When the working fluid has a high pressure, the working fluid is sealed against the pressure and impact pressure of the working fluid.

The urging ring urges the first sliding surface, which comes into close contact with the sliding surface of the other member in the case of high pressure, in the direction of separating from and in contact with the close surface, so that the second ring can be moved in the case of low pressure. The sliding surface of the other member is in close contact with the sliding surface of the other member, and the gap between the first sliding surface of the seal ring and the sliding surface of the other member can be reduced. The sealing property of the sliding surface of No. 1 is improved.

The pressing ring has a first position on the seal ring for applying a close contact pressure to the first sliding surface at a high pressure and a second position for applying a close contact pressure on the second sliding surface at a low pressure.
The contact pressure is selectively applied to the respective sliding surfaces according to the pressure of the working fluid by being configured to be movable to the position of and.

Further, by providing the sealing device of the present invention on the pressure side of the main seal, the working fluid communicates through the sealing device through the flow passage provided on the second sliding surface to operate when the pressure is low. The fluid is guided to the main seal to maintain the performance by lubricating the seal member of the main seal, and when the working fluid is at high pressure, it seals the working fluid against the pressure and impact pressure of the working fluid, Protect against damage.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of a hydraulic cylinder to which a sealing device of the present invention is applied.

FIG. 2 is an explanatory view of a main part of a D2 portion of the rod cover 5.

FIG. 3 is a diagram of a protective sealing device 6.

FIG. 4 is a view of a biasing ring.

FIG. 5 is an operation explanatory view of the protective seal device 6 of the present invention.

FIG. 6 is an example of an operation explanatory view of the protective seal device 6 of the present invention.

FIG. 7 is a diagram of a seal ring according to a second embodiment of the present invention.

FIG. 8 is a diagram of a sealing device according to a third embodiment of the present invention.

FIG. 9 is a cross-sectional explanatory view of a conventional hydraulic cylinder.

FIG. 10 is an explanatory view of a main part of a rod portion of a conventional hydraulic cylinder.

FIG. 11 is an explanatory diagram of a conventional protective seal device.

FIG. 12 is an explanatory diagram of an example of a conventional protective seal device.

[Explanation of symbols]

 1,101 Hydraulic cylinder 2 Cylinder inner hole (cylinder member) 3 Piston 4 Rod (piston member) 5 Rod cover 6 Protective seal device (seal device) 7 Main seal 8 Dust seal 11,21,31 Seal ring 11a, 21b, 31c 1 sliding surface 11b, 21b, 31c 2nd sliding surface 11c, 21c flow path 11d annular groove 11e corner 12 pressing ring 13 urging ring L working fluid

Claims (4)

[Claims] 1. A seal ring which closely slides on a sliding surface of the other member in an annular groove formed in an opposing peripheral surface of one of the cylinder member and the piston member which are fitted relative to each other, and the seal ring. In a sealing device in which a pressing ring for applying a close pressure to the member is fitted and inserted, the sealing ring has a first sliding surface that is in sliding contact with the other member at a high pressure, and a predetermined angle from the first sliding surface. A second sliding surface that is inclined at a low temperature and slides in contact with the other member when the pressure is low, and a flow path that allows fluid to communicate in the axial direction while the second sliding surface is in sliding contact with the other member when the pressure is low And a sealing device. 2. A ring-shaped groove formed in the seal ring is fitted in a direction in which the first sliding surface is brought into contact with and separated from the sliding surface of the other member by a predetermined pressing force by a spring force. The sealing device according to claim 1, further comprising a biasing ring that biases the sealing device. 3. The pressing ring, on the seal ring, applies a close pressure to the first sliding surface at a high pressure and a close position to the second sliding surface at a low pressure. The sealing device according to claim 1 or 2, wherein the sealing device is configured to be movable to a second position. 4. The sealing device according to claim 1, wherein the sealing device is provided on the pressure side of a main seal that seals between relatively moving members.