JP2005331060A - O ring - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an O ring capable of excellently forming and holding a lubricating oil film between pressure-contacting cylindrical members. <P>SOLUTION: A recessed groove 7 for defining an oil reservoir 6 of lubricating oil between the cylindrical members 4, is formed on the outer periphery of the O ring 1. When the O ring 1 slides in a state of being brought into pressure contact with the cylindrical members 4, the lubricating oil held in the recessed groove 7 is pushed outside the recessed groove 7 by elastic deformation of the O ring 1, and the excellent oil film is always formed between the cylindrical members 4. At the same time, the oil of a peripheral surface of the cylindrical members 4 is properly scratched off by the O ring 1, and the lubricating oil is replenished in the recessed groove 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is mounted in an annular groove formed on the peripheral surface of the first cylindrical member, and has a circular cross section that seals between the first cylindrical member and the second cylindrical member that move relative to each other. This relates to the improvement of the O-ring.

Such an O-ring is interposed between, for example, a piston as a first cylindrical member and a cylinder tube as a second cylindrical member constituting a high-pressure injection device, and moves relative to each other. The space between the piston and the cylinder is sealed. The O-ring is usually formed in an annular shape with an elastic member such as rubber or synthetic resin, and the cross-sectional shape is generally circular (Patent Document 1).
Shoko 62-42206 (see Fig. 2)

  However, when the first cylindrical member and the second cylindrical member perform relative movement, the O-ring that is pressed against and slides on the second cylindrical member is compressed and deformed. The pressure contact area with respect to the second cylindrical member is increased. For this reason, the friction between the O-ring and the second cylindrical member becomes too large, and it becomes difficult to satisfactorily hold a lubricating oil film between the second cylindrical member, There is a problem that smooth relative movement between the first cylindrical member and the second cylindrical member is hindered.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an O-ring that can satisfactorily form and hold a lubricating oil film with a cylindrical member that is in pressure contact.

  In order to solve the above-mentioned problem, the O-ring according to the present invention is formed in an annular shape with an elastic member, and is attached to an annular groove formed in the first cylindrical member and is in pressure contact with the second cylindrical member. In the O-ring having a circular cross-section that slides relative to each other, a concave groove that defines a sump of lubricating oil between the second cylindrical member and the second cylindrical member is formed on the pressure contact surface with respect to the second cylindrical member. (Claim 1).

  According to the present invention, when the O-ring slides in a state of being pressed against the second cylindrical member, the lubricating oil held in the concave groove is moved out of the concave groove by elastic deformation of the O-ring. Extruded and a good oil film is always formed between the second cylindrical member. At the same time, oil on the peripheral surface of the second cylindrical member is appropriately scraped off by the O-ring, and lubricating oil is replenished in the concave groove. Further, in the O-ring, the contact area between the O-ring and the second cylindrical member is reduced from the beginning by the opening area of the concave groove as compared with a conventional O-ring having a circular cross-sectional shape. As a result, the frictional force with the second cylindrical member is reduced from the beginning. This can also contribute to good formation of the oil film.

  According to the O-ring, since the relative protrusions on both sides of the concave groove are always in close contact with the second cylindrical member, the sealing performance by the O-ring does not deteriorate.

  As a preferred embodiment, the concave groove may be formed over the entire circumference of the pressure contact surface with respect to the second cylindrical member (claim 2). If it does in this way, lubricating oil will be supplied satisfactorily from the said ditch | groove to the perimeter of said 2nd cylindrical member, and it is suitable.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is an explanatory view including a plan view and a partially broken front view of an O-ring according to an embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view of a main part of the O-ring in FIG. .

  As shown in FIG. 1, the O-ring 1 according to the present embodiment is formed in an annular shape (ring shape) by an elastic member such as rubber or synthetic resin. As shown in FIG. 2, the O-ring 1 is attached to, for example, an annular groove 3 having a substantially rectangular cross section formed on an outer peripheral surface 2a of a piston 2 as a first cylindrical member constituting a high pressure injection device. Used. The piston 2 is fitted into a cylinder tube 4 as a second cylindrical member that constitutes the high-pressure injection device together with the piston 2. The piston 2 and the cylinder tube 4 make relative movements along the axial direction. The O-ring 1 slides relative to the inner peripheral surface 4 a of the cylinder tube 4 while maintaining a sealed state between the piston 2 and the cylinder tube 4.

  The O-ring 1 is provided with a concave groove 7 that defines an oil reservoir 6 between the inner peripheral surface 4 a of the cylinder tube 4 and a pressure contact surface 5 with respect to the cylinder tube 4. Specifically, as shown in FIG. 1, the O-ring 1 has a configuration in which a concave groove 7 extending in the circumferential direction is formed on the outer peripheral surface of an O-ring material having a circular cross section. The concave groove 7 is formed over the entire circumference of the O-ring material. As a result, an annular space 6 is defined between the concave groove 7 and the inner peripheral surface 4a of the cylinder tube 4 in a state where the O-ring 1 is pressed against the cylinder tube 4. . The annular space 6 functions as an oil sump for holding lubricating oil that lubricates between the O-ring 1 and the cylinder tube 4.

  Next, the operation of the O-ring 1 will be described with reference to FIG. When the O-ring 1 is mounted in the annular groove 3 of the piston 2 and the piston 2 is fitted into the cylinder tube 4 in this state, the piston 2 is positioned slightly outward in the radial direction from the outer peripheral surface 2a of the piston 2. The outer peripheral surface 5 of the O-ring 1 is in pressure contact with the inner peripheral surface 4 a of the cylinder tube 4. In this state, the relative protrusions (relative ridges) 8 and 8 on both sides of the concave groove 3 in the O-ring 1 are firmly attached to the inner peripheral surface 4 a of the cylinder tube 4. Yes. Thereby, the oil sump 6 is defined between the O-ring 1 and the inner peripheral surface 4 a of the cylinder tube 4. Lubricating oil for lubricating the space between the O-ring 1 and the inner peripheral surface 4a of the cylinder tube 4 is applied in advance. Therefore, the lubricating oil enters and is held in the oil sump 6.

  When the piston 2 is moved to the right in FIG. 2 along the axial direction with respect to the cylinder tube 4, the O-ring 1 is compressed and deformed due to an increase in contact pressure with the cylinder tube 4. Accordingly, the cross-sectional shape of the oil sump 6 is also deformed, for example, as shown in FIG. As a result, the lubricating oil held in the concave groove 7 is pushed out of the oil reservoir 6, and a good oil film is always formed between the cylinder tube 4. At the same time, the lubricating oil adhering to the inner peripheral surface 4 a of the cylinder tube 4 is appropriately scraped off by the relative protrusion 8 of the O-ring 1, and the lubricating oil is replenished into the concave groove 7. The

  As described above, according to the O-ring 1, a good oil film is always formed between the O-ring 1 and the cylinder tube 4. Therefore, even when the piston 2 is operated at a high pressure, Therefore, the relative movement between the piston 2 and the cylinder tube 4 is always performed smoothly. Further, according to the O-ring 1, compared with a conventional O-ring having no circular groove 7 and having a circular cross section, the contact area with the cylinder tube 4 is the same as the opening area of the concave groove 7 from the beginning. Since it decreases, the frictional force with the inner peripheral surface of the cylinder tube 4 is reduced from the beginning. This can also contribute to good formation of the oil film.

  Further, in the present embodiment, since the concave groove 7 is formed over the entire outer periphery of the O-ring 1, lubrication is performed from the concave groove 7 to the entire inner periphery of the cylinder tube 4. Oil is well supplied and is preferred.

  According to the O-ring 1, the relative protrusions 8 and 8 on both sides of the concave groove 7 are always in close contact with the inner peripheral surface 4 a of the cylinder tube 4. There is no problem of lowering.

It is explanatory drawing which consists of a top view of the O-ring which concerns on one Embodiment of this invention, and a partially broken front view. It is a principal part expanded sectional view of the use condition of the O-ring of FIG.

Explanation of symbols

1 O-ring 2 First cylindrical member (piston)
3 Annular groove 4 Second cylindrical member (cylinder tube)
5 Pressure contact surface to second cylindrical member 6 Oil sump 7 Groove

Claims (2)

  It is formed in an annular shape with an elastic member and is relatively slid in a state of being attached to an annular groove (3) formed in the first cylindrical member (2) and being pressed against the second cylindrical member (4). In the O-ring (1) having a circular cross section, the oil reservoir (6) between the pressure contact surface (5) against the second cylindrical member (4) and the second cylindrical member (4) is provided. O-ring in which a concave groove (7) is formed.   The O-ring according to claim 1, wherein the concave groove (7) is formed over the entire circumference of the pressure contact surface (5) with respect to the second cylindrical member (4).

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