JP3058632B1 - Ultra-low resistance sliding seal structure with O-ring - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To provide a stable sealing action with a simple structure to smoothly slide a sliding shaft, etc., and to set an arbitrary sealing pressure without generating torsion, wear, etc., to obtain an optimum sliding resistance. Proposal of obtained technology. SOLUTION: Casing 1 such as rotary joint
In the structure in which the shaft 15 is loosely fitted in the hole 13 and the O-ring 6 is attached to a groove provided in one of the hole and the shaft, and the shaft supporting portion is slidably sealed, the groove 5 is A fluid pressure supply path 7 is formed at a groove bottom 5a formed by a side wall 5b which slidably contacts the both side surfaces of the O-ring and holds the O-ring so as to be able to expand and contract in the diametrical direction. When a fluid pressure is supplied from the groove bottom 5a to the inner or outer diameter surface of the O-ring, the O-ring 6 expands or contracts in diameter and contacts the sliding surface to perform a sealing action. Configuration having.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal in which a seal structure is formed by an O-ring, wherein a very small sliding resistance and starting resistance and a good sealing action after sliding can be obtained. More particularly, the present invention relates to an ultra-low-resistance sliding seal structure using an O-ring suitable for a rotary joint or the like through which a coolant or an oil mist having a small fluid pressure passes.

[0002]

2. Description of the Related Art Conventionally, a seal structure using an O-ring is often used for a shaft portion seal such as a cylinder, a piston, a rotary joint or the like in which a seal surface moves (moves). For example, in a rotary joint used for a general machine or the like, as shown in FIG.
4 is provided with a shaft portion 55 in a fluid supply passage 53 formed in a casing 52, and a seal ring 51 on the other side is
6 and the shaft 55 of the floating sheet is connected to the fluid supply passage 5 through an O-ring 57.
3 is supported in a floating state and is pressed in the direction of the rotation shaft 56 by a spring 58 so that the seal rings face each other and the fixed side and the rotation side are connected to form a flow path. . In this case, the O-ring 57 is sufficiently compressed in the diametrical direction between the groove bottom 60 and the outer peripheral surface (sliding surface) of the shaft portion 55 in the mounting groove 59 to be in a compressed state. In the state, the fluid 62 from the high pressure side gap 61
The sealing function is achieved in a state of being tightly contacted with the low-pressure side gap 63 at the pressure of.

[0003]

If the reciprocating movement of the seal surface is very fast, there is a problem that the life of the seal is extremely short due to twisting or wear of the O-ring or the like. In recent years, with respect to the above-described apparatus, there has been a review of a processing method and an energy loss that consume a large amount of coolant or oil, and there has been a demand that a very stable operation can be obtained even under adverse conditions. For example, in the rotary joint as described above, there is an operation in which the rotary shaft 56 is once separated from the floating seat 54 by the advancing and retreating action of the drawbar and then returns to the original position. Under such conditions that the seal rings are once separated from each other, if a processing method for reducing the amount of the coolant used or a dry process without using the coolant is adopted, a spring for bringing the seal rings into close contact with each other due to a problem such as heat generation. Since the floating sheet cannot be used, the floating sheet must be sensitively slidable only with a weak pressing force. In such a case, the O-ring 57 that supports the shaft portion 55 of the floating sheet in a floating state is set in a compressed state in the mounting groove 59, and the crushing rate is gradually reduced to a minimum. It is possible. However, there is a problem that this state is extremely unstable in terms of various precisions and a large variation occurs in the sliding resistance.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. It is an object of the present invention to perform a stable sealing action with a simple structure and to slide a cylinder, a piston, and a rotary joint. It is an object of the present invention to provide an ultra-low-resistance sliding seal structure using an O-ring, which can slide a shaft and the like extremely smoothly, does not easily generate torsion, abrasion, and the like, and extends the life of the seal. . Further, the present invention has a simple structure in which the sealing pressure is arbitrarily set and an optimal sliding resistance is obtained.
An object of the present invention is to provide an ultra-low resistance sliding seal structure using a ring.

[0005]

In order to solve the above problems SUMMARY OF THE INVENTION, in the ultra-low resistance sliding seal structure according to the O-ring of the present invention according to claim 1, wherein the loosely fitted axis in the hole of the casing In a structure in which an O-ring is mounted in a groove provided on a shaft to slidably seal the shaft support portion, the groove slidably contacts both side surfaces of the O-ring to make the O-ring have a diameter. A fluid pressure supply port is formed at the bottom of the groove and formed by a side wall which is held so as to be expandable in the direction, and a sliding surface opposed to the groove has a gap between the sliding surface and the outer diameter surface of the O-ring. The gap is set to have such a size that when the fluid pressure is supplied from the groove bottom, the O-ring expands in diameter and comes into contact with a sliding surface to perform a sealing action.

[0006] In the ultra-low resistance sliding type seal structure using the O-ring according to the second aspect, the sealing surface arranged at the leading end of the floating seat of the rotary joint is brought into close contact with the sealing surface on the rotating shaft side to allow the floating joint. In order to allow the flow path penetrated through the floating shaft portion of the sheet to communicate with the flow path on the rotating shaft side, the floating shaft portion of the floating sheet is slidably connected to the fluid supply path formed in the casing via an O-ring. In the mounted sliding seal structure, the groove for mounting the O-ring is formed by a side wall that slidably contacts both side surfaces of the O-ring and holds the O-ring so as to be diametrically expandable. A fluid pressure supply port is opened at the bottom, and the sliding surface facing the groove is the O-ring.
A gap is provided between the O-ring and the sliding surface when the fluid pressure is supplied from the bottom of the groove, and the gap is set to a size that performs a sealing action by contacting the sliding surface. And the fluid pressure supply port is connected to the fluid supply path or another pressure source.

According to a third aspect of the present invention, there is provided an ultra-low resistance sliding type seal structure using an O-ring according to the first or second aspect . At least one of the side walls is provided so as to be inclined so as to widen the groove bottom width with respect to the opening width of the groove.

[0008]

In the ultra-low resistance sliding seal structure using the O-ring according to the first, second and third aspects, the sliding resistance and the starting resistance are extremely low because there is no crushing of the O-ring or the like. In the state (theoretical resistance due to the seal is 0), the movement (movement) of the seal surface can be performed. Therefore, a smooth movement of the cylinder, the piston, and the like can be obtained, and the sealing effect does not decrease due to abrasion or the like. After the movement of the sealing surface is in a stopped state or a state similar to the stopped state (the state is not completely stopped, but is a state sufficient to generate a pressure for causing the O-ring to have a sealing action), the internal pressure or the external pressure causes Since it is a structure that performs the original sealing function, it is difficult for the O-ring or the like to be twisted or worn, and the life of the seal portion can be extended. In a seal portion equipped with a seal ring seizure prevention reverse spring that enables dry operation, the sealing action of the O-ring due to the presence or absence of fluid pressure and the opening and closing of the seal portion by the biasing force of the reverse spring work well. It is possible to extend the life of the O-ring without giving unnecessary vibrations to the O-ring. Since it is not a structure in which an O-ring or the like is constantly sealed in a crushed form, a uniform sealing structure with less variation than before can be obtained even in mass production. Further, even with a simple structure, an optimum sliding resistance can be obtained by arbitrarily setting the sealing pressure, so that it is possible to cope with various use conditions.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings, taking a rotary joint as an example. FIG.
1 shows an ultra-low resistance sliding type seal structure using an O-ring of a rotary joint according to the present embodiment, (a) is a cross-sectional view showing a state before the seal rings are in close contact, and (b) is a state in which the seal rings are in close contact. FIG. 2 is a cross-sectional view showing a state where the rotating shaft pushes the floating sheet. In these figures, the detent of the floating sheet is omitted.

First, the rotary joint R is provided so as to supply the oil mist M to the tool side of the machine tool. The rotary joint R has a casing 1, a floating seat 2, and an ultra-low resistance sliding type using an O-ring. Seal structure 3
And the flow path seal portion 4 as main components.

The casing 1 is formed in a substantially cylindrical shape with a bottom, has a fluid supply passage 13 inside, and has a connection port communicating with the outside penetrating the bottom surface side.

The floating sheet 2 connects the fixed-side flow path and the rotation-side flow path, and a floating shaft portion 15 (the outer peripheral surface of which is a sliding surface) slides in the fluid supply passage 13. The flange 16 is provided with a notch (not shown), and the shaft 18 is provided with a passage 18 therethrough. The inner diameter of the fluid supply path 13 is such that the floating shaft 15 can smoothly slide without rattling,
When the ring 6 is mounted in the groove 5 of the floating shaft 15 to be in a free state, a small gap 8 is formed between the ring 6 and the outer diameter of the O-ring.

The ultra-low-resistance sliding type seal structure 3 formed by the O-ring seals between the fluid supply passage 13 and the floating shaft 15 when a predetermined pressure is generated. It is composed of a groove 5 provided on the outer peripheral surface, an O-ring 6 mounted on the groove 5, and a large number of communication paths 7 communicating the fluid supply path 13 with the groove bottom 5a side of the groove 5. I have. The groove 5 has a depth such that the O-ring outer diameter side does not protrude from the outer peripheral surface of the floating shaft 15 when the O-ring 6 is mounted and is in a free state or slightly in contact with the groove bottom 5a. The O-ring is formed so as to have side walls 5b that come into light contact with both side surfaces. In addition, the groove 5
Is provided by inclining the side walls 5b, 5b so as to have an opening width slightly smaller than the outer diameter of the O-ring 6.

Reference numeral 9 denotes a rotary tube shaft which is detachably mounted by being screwed into a main shaft 19 of a machine tool.
A passage 20 having the same diameter as that of the passage 8 is provided through the passage. The rotary tube shaft 9 and the floating sheet 2 are arranged so that their axes are aligned and their end faces are opposed to each other.

The flow path seal portion 4 is provided with a seal ring 21 fixed to an end face of the floating sheet 2.
And a set of seal rings 22 fixed to the end face of the rotary tube shaft 9 and are made of cemented carbide or ceramic. The casing 1 is provided with locking pins so as to prevent the floating seat 2 from rotating.

The rotary joint R configured as described above is connected to an oil mist generator having a connection port provided outside. When the oil mist M is supplied from the oil mist generator, the oil mist M is squeezed from the connection port of the casing 1 in the flow path 18 of the floating sheet 2 and the floating sheet 2 is moved toward the rotating pipe shaft 9 by the generated pressure. Press. The floating sheet 2 is slid by the pressing force, and the sealing ring 21 at the tip is brought into close contact with the sealing ring 22 on the rotating tube shaft side. Thereafter, the oil mist M increases the pressure due to the flow resistance on the main shaft side,
The oil mist M having the increased pressure flows into the groove bottom 5a via the communication passage 7 to expand the diameter of the O-ring 6.

Due to the diameter expansion of the O-ring 6, the outer peripheral surface of the O-ring 6 comes into contact with the inner peripheral surface of the fluid supply passage 13 to seal the space between the O-ring 6 and the floating shaft 15. Due to the sealing action of the O-ring, the entire amount of the oil mist M is supplied to the main shaft side without leaking from anywhere. Then, when the supply of the oil mist M is stopped, the oil mist M is returned to the initial state in a procedure substantially opposite to the above, and waits.

Although the embodiment of the present invention has been described above, the specific configuration of the present invention is not limited to this embodiment. As shown in FIG. 3, the O-ring 6 has a boss outer peripheral surface 25 forming the fluid supply passage 13 of the casing.
And the communication path 7 may be connected to another external pressure source. In this case, the floating sheet 26 is formed in a cylindrical shape with a bottom and has a structure in which the cylindrical portion 26a is externally fitted to the boss portion. Further, as shown in FIG. 4, in the structure in which the floating sheet formed into a bottomed cylindrical shape is fitted to the boss portion, the communication path 7 may be connected to the fluid supply path 13. As shown in FIG. 5, the floating seat 2 is provided with a two-sided width portion 27 on the floating shaft 15 of the floating seat, into which a detent 28 formed in a substantially U shape by a plate is inserted, and a bolt is attached to the casing 1 side. 3
It may be made to be detachably fixed at 0. As shown in FIG. 6, a cylindrical mounting base 29 is detachably mounted on the casing 1 side with bolts 30 so as to communicate with the fluid supply path 13, and the floating sheet 2 is mounted on the casing 1 via the mounting base 29. The rotation stopper may have a structure in which the shaft 31 protruding from the mounting base 29 is inserted through a through hole 33 formed in the flange 32 of the floating sheet. In this case, by attaching and detaching the mounting base 29, the floating seat 2
There is an advantage that the seal structure portion on the side can be integrally attached and detached, thereby facilitating maintenance and inspection. Although the example in which the groove 5 of the O-ring is arranged on the floating shaft 15 side has been described, it may be arranged on the fluid supply path 13 side of the casing as shown in FIG. In this case, various sealing effects can be obtained by connecting the communication path 7 to another external pressure supply means instead of the fluid supply path and adjusting the pressure arbitrarily. Further, in the present embodiment, the ultra-low resistance sliding type seal structure using the O-ring has been described by taking as an example the case where the seal structure is used for a rotary joint. For example, the present invention can be applied to air cylinders and dampers with improved sensitivity. The shape of the groove 5 can be set arbitrarily. For example, only one side wall may be inclined, or both side walls may be formed so as to be parallel to a normal groove shape and perpendicular to the groove bottom. . The structure and shape of the rotary joint itself can be arbitrarily set. The seal material forming the seal portion is described by the name of the O-ring. However, as long as the O-shaped ring is used, O-rings having various specifications such as a material, a shaft cross-sectional shape, and a surface treatment can be used.

[0019]

As described above, according to the present invention ,
In the ultra-low-resistance sliding type seal structure using the O-ring described in the paragraphs 1 and 2 , the sliding resistance and the starting resistance are extremely low (theoretically) because the above-described configuration eliminates the crushing allowance of the O-ring and the like. (The resistance of the seal is zero), the movement (movement) of the seal surface can be performed. Therefore, a smooth movement of the cylinder, the piston, and the like can be obtained, and the sealing effect does not decrease due to abrasion or the like. After the movement of the sealing surface is in a stopped state or a state similar to the stopped state (the state is not completely stopped, but is a state sufficient to generate a pressure for causing the O-ring to have a sealing action), the internal pressure or the external pressure causes Since it is a structure that performs the original sealing function, it is difficult for the O-ring or the like to be twisted or worn, and the life of the seal portion can be extended. The O-ring can be prolonged in life by acting well on a seal portion provided with a reverse spring for preventing sticking of the seal ring to enable the dry operation to perform a good and stable sealing action. Since it is not a structure in which an O-ring or the like is always sealed in a crushed form, an effect such as a more uniform sealing structure having less variation than before can be obtained even in mass production.

According to the third aspect of the present invention, the ultra-low resistance sliding type seal structure using the O-ring has the above-mentioned structure. Is obtained, so that effects such as adaptation to various use states can be obtained.

[Brief description of the drawings]

FIG. 1 shows an ultra-low-resistance sliding-type seal structure using an O-ring of a rotary joint according to the present embodiment;
Is a cross-sectional view showing the state before the seal rings adhere to each other, (b)
FIG. 3 is a cross-sectional view showing the state of the close contact.

FIG. 2 is a cross-sectional view showing a state where a rotating shaft pushes a floating sheet.

FIG. 3 is a cross-sectional view showing a rotary joint that provides an O-ring according to another embodiment on an outer peripheral surface of a fluid supply path of a casing and connects a communication path to another external pressure source.

FIG. 4 is a sectional view showing a rotary joint in which an O-ring according to another embodiment is provided on an outer peripheral surface of a fluid supply path of a casing and a communication path is connected to the fluid supply path.

FIG. 5A is a front view showing a rotation preventing structure using a plate according to another embodiment, and FIG. 5B is a cross-sectional view showing a rotary joint incorporating the rotation preventing structure using the above plate.

FIG. 6 is a cross-sectional view illustrating a rotary joint according to another embodiment, in which a rotation preventing mechanism provided with a shaft projection and a seal portion structure via a mounting base for a floating seat are incorporated.

FIG. 7 is a cross-sectional view showing a rotary joint incorporating a seal structure having an O-ring provided on a hole side according to another embodiment.

FIG. 8 is a sectional view showing a conventional rotary joint.

[Explanation of symbols]

 R Rotary joint 1 Casing 2 Floating sheet 3 Ultra-low resistance sliding type seal structure with O-ring 5 Groove 5a Groove bottom 5b Groove sidewall 6 O-ring 7 Communication path 8 Gap 13 Fluid supply path 15 Floating axis of floating sheet Part 18 Floating sheet flow path 21, 22 Seal ring

Claims (3)

(57) [Claims] 1. A slidably sealed structure shaft support portion by the shaft into the hole of the casing for mounting the O-ring to circumferentially provided by a groove in the shaft is loosely fitted, said groove of said O-ring A fluid pressure supply port is formed at the bottom of the groove formed by a side wall which slidably contacts the both side surfaces and holds the O-ring so as to be diametrically expandable, and a sliding surface facing the groove is provided. A gap is provided between the O-ring and the outer diameter surface thereof, and the gap is increased by supplying a fluid pressure from the groove bottom, whereby the O-ring expands in diameter and comes into contact with the sliding surface to seal. An ultra-low-resistance sliding-type seal structure using an O-ring, which is set to a size for performing an action. 2. A flow path penetrated through the floating shaft portion of the floating sheet is brought into close contact with a sealing surface arranged at the tip of the floating sheet of the rotary joint on the rotating shaft side. In order to communicate,
In a sliding seal structure in which a floating shaft portion of the floating sheet is slidably mounted via an O-ring on a fluid supply passage formed in a casing, grooves for mounting the O-ring are formed on both sides of the O-ring. supply port of the fluid pressure is opened to slidably contact with the O-ring in the groove bottom while being formed by the side wall of expandable held in diameter direction, the sliding surface to further facing the groove the O A gap is provided between the O-ring and the outer diameter surface of the ring, and this gap provides a sealing effect by expanding the O-ring and contacting the sliding surface when fluid pressure is supplied from the groove bottom. An ultra-low resistance sliding seal structure using an O-ring, wherein the size is set to a value to be performed, and the fluid pressure supply port is connected to the fluid supply path or another pressure source. 3. to claim 1 or claim 2, characterized in that one side wall of at least the side walls so as to widen the groove bottom width to the opening width of the groove is provided obliquely with < An ultra-low-resistance sliding-type seal structure using the O-ring described in <br/>.