JP2004225778A - Sealing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing unit prepared into a circular gap between a shaft member and an outer enclosure member, which is capable of assuring a high sealing capability for a long term from an initial stage of mounting. <P>SOLUTION: The sealing unit 10 such as a seal used for a high pressure fuel injection pump has a gap S1 between an outer periphery and a sealing face of a first circular member 40 and an inner periphery and a sealing face of a second circular member 50 in a contact face 43B (53B) of the first circular member 40 and the second circular member 50. The first circular member 40 and the second circular member 50 are made of a material with high rigidity such as metal, resin or the like. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sealing device that exhibits sealing properties even in an environment such as a seal for a high-pressure fuel injection pump.
[0002]
[Prior art]
2. Description of the Related Art In recent years, in a diesel engine, a gasoline engine, and the like, in-cylinder direct injection systems in which high-pressure fuel is directly injected into a cylinder and burned have been developed in order to improve performance such as low fuel consumption and high output.
[0003]
Such a direct injection type engine requires a high-pressure fuel pump for pressurizing the fuel to a high pressure, and the high-pressure fuel pump uses a reciprocating sealing device that requires high-pressure sealing. Have been.
[0004]
FIG. 4 shows a conventional sealing device. The sealing device 100 shown in FIG. 4 is used for sealing high-pressure fuel supplied from a high-pressure fuel pump used in an engine that performs fuel injection to a high-pressure side of the shaft 120 that reciprocates in the axial direction. Is what is done.
[0005]
As shown in FIG. 4, the sealing device 100 is housed in an annular groove 122 provided around an outer peripheral surface 121 of a shaft member 120, and a bottom surface 122 a of the annular groove 122 and a cylindrical inner periphery of the outer member 130. The gap between the two members 120 and 130 is sealed by the surface pressure generated by being crushed between the surfaces 131.
[0006]
Here, the shape and size of the sealing device 100 are determined so that the sealing device 100 generates a predetermined surface pressure on the shaft member (the bottom surface of the annular groove) and the outer member (the inner peripheral surface). It is designed with anticipation.
[0007]
In such a sealing device 100, there has been a problem that the crushing allowance is reduced (creep) due to long-term use, and the sealing performance is reduced.
[0008]
Further, as shown in FIG. 5, for example, a structure is also known in which a certain amount of movement is allowed in the sealing device 200 in a space S100 formed by the annular groove 122 of the shaft member 120 and the inner peripheral surface 131 of the outer member 130. Have been. In such a structure, when the fluid pressure P100 or the fluid pressure P200 is applied to the gap between the shaft member 120 and the outer member 130 along the axial direction, the sealing device 200 moves in the direction in which the fluid pressure is applied, The gap between the two members 120 and 130 is sealed (see FIGS. 5A and 5B). Generally, such a sealing structure is used to seal a gap between the shaft member 120 and the outer member 130 that move relatively differently along the axial direction. However, if this sealing structure is adopted under the condition that the fluid pressure is alternately applied from both sides along the axial direction of the shaft member 120 and the outer shell member 130, the leakage of the fluid when the direction in which the fluid pressure is applied is switched. (Refer to FIG. 5 (c). Note that the dotted line in the figure indicates the flow path of leakage that occurs when the applied fluid pressure switches from the P100 direction to the P200 direction.) That is, also in this case, it has been difficult to secure sufficient sealing performance.
[0009]
In order to solve such a problem, for example, Patent Document 1 discloses that two annular members having tapered surfaces along the axial direction are formed as shown in FIGS. 6 (a) and 6 (b). It describes a sealing device that is superimposed in an opposed state.
[0010]
In such a sealing device 300, when the fluid pressure P100 or the fluid pressure P200 is applied to the gap between the shaft member 120 and the outer member 130 along the axial direction, the annular members 340 and 350 configuring the sealing device are provided. On the other hand, when the forces F10 and F20 act in the radial direction of the shaft member 120, a part of one of the two annular members 340 and 350 constituting the sealing device 300 becomes partially outer with the other annular member 340. It bites into the inner peripheral surface 131 of the member 130 appropriately. Accordingly, a high surface pressure is generated between the sealing device 300 and the shaft member 120 (the bottom surface 122a of the annular groove 122), and between the sealing device 300 and the outer member 130 (the inner peripheral surface 131). High sealing performance is secured in the gap between the outer members 130.
[0011]
[Patent Document 1]
JP-A-63-008476 [Patent Document 2]
JP-A-56-101258 [0012]
[Problems to be solved by the invention]
By the way, in the sealing device 300 as shown in FIG. 6, the shaft member 120 and the shaft member 120 until the part of the one annular member 350 bites between the other annular member 340 and the inner peripheral surface 131 of the outer member 130. The outer member 130 needs to repeat the relative movement along the axial direction for a while. In other words, after the sealing device 300 is mounted in the gap between the shaft member 120 and the outer shell member 130, high sealing properties cannot be expected in the gap at an early stage of use. Further, since the annular member 350 has a predetermined squeeze allowance protruding from the annular groove 122, when the annular member 350 is used for a member other than the fixing seal member (for example, for rotation, reciprocating movement, and swinging), it is gradually used. Squeeze allowance is worn. As a result, it is not possible to ensure the sealing performance for a long time.
[0013]
The present invention has been made in view of such circumstances, and its purpose is to provide an annular gap even in an environment where low-strength materials such as rubber cannot be used, from the initial stage of mounting. Another object of the present invention is to provide a sealing device capable of guaranteeing high sealing performance over a long period of time.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is provided on one of the outer shell member and the shaft member so as to seal an annular gap between the outer shell member and a shaft member attached to a cylindrical hole of the outer shell member. A sealing device mounted in an annular groove, comprising: a first rigid member having a high rigidity; and a second rigid member having a high rigidity disposed in contact with the first annular member. In a contact portion with the second annular member, a gap is provided between an outer peripheral surface and a sealing surface of the first annular member and between an inner peripheral surface and a sealing surface of the second annular member. Make a summary.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to them unless otherwise specified. The materials, shapes, and the like of the members once described in the following description are the same as those in the first description unless otherwise specified.
[0016]
(First Embodiment)
FIG. 1 is a schematic view showing a partial cross section of a first preferred embodiment of a sealing device according to the present invention. That is, the sealing device 10 of the present embodiment is used, for example, in a sealing portion of a high-pressure fuel pump mounted on an internal combustion engine, and surrounds a shaft member 20 and an outer peripheral surface 21 of the shaft member 20 as shown in FIG. It is arranged in an annular groove 22 formed on the outer peripheral surface 21 of the shaft member 20 in a gap between the outer peripheral member 30 having a cylindrical inner peripheral surface 31.
[0017]
The sealing device 10 includes a first annular member 40 and a second annular member 50. The first annular member 40 has an inner peripheral surface 42, an outer peripheral surface 41, and a tapered peripheral surface 43. The second annular member 50 has an outer peripheral surface 52, an inner peripheral surface 51, and a tapered peripheral surface 53. A part (contact surface) 43A of the tapered peripheral surface 43 and a part (contact surface) 53A of the tapered peripheral surface 53 contact each other. The gap S1 is defined by the end surface 44 of the first annular member 40, the annular groove bottom 22a of the shaft member 20, and a part (a portion excluding the contact surface 53A) 53B of the tapered peripheral surface 53 of the second annular member 50. Are formed in the circumferential direction. Further, the end surface 54 of the second annular member 50, the inner peripheral surface 31 of the outer shell member 30, and a part (a portion excluding the contact surface 43 </ b> A) 43 </ b> B of the tapered peripheral surface 53 of the first annular member 40, A gap S2 is formed in the circumferential direction.
[0018]
The first annular member 40 and the second annular member 50 are formed of a highly rigid material whose main material is metal (for example, copper, aluminum, or the like) or resin (for example, PTFE, ETFE, PEEK, nylon, or the like). The hardness of these materials is preferably selected as appropriate according to the conditions of use (pressure, etc.) and the size used (dimensions of the annular groove and the annular member, the amount of the members overlapping each other in the axial direction, etc.).
[0019]
Here, as shown in FIGS. 2A, 2B, and 2C, the first annular member 40 or the second annular member 40 extends along the axial direction of the shaft member 20 (hereinafter, simply referred to as the axial direction). When the fluid pressure P1 or the fluid pressure P2, the fluid pressure P1 and the fluid pressure P2 alternately, or both the fluid pressure P1 and the fluid pressure P2 are applied to the annular member 50, the first annular member 40 and The second annular member 50 comes into contact with each of the tapered surfaces (contact surfaces) 43A and 53A and presses each other. Then, a force F1 is applied to the first annular member 40 toward the bottom surface 22a of the annular groove 22, and the first annular member 40 quickly bites (in the direction of arrow D1) into the gap S1 at the apex of the first annular member. In addition, a force F2 toward the inner peripheral surface 31 of the outer member 30 is applied to the second annular member 50, and the second annular member 50 is also quickly moved to the gap S2 at the apex portion (in the direction of arrow D2). Into).
[0020]
Therefore, from the initial stage of use, the first annular member 40 bites into the gap at the apex of the apex and the second annular member 50 bites into the apex of the apex. Therefore, high sealing performance can be secured in the annular gap between the shaft member 20 and the outer shell member 30 from the initial stage of use.
[0021]
Further, according to the sealing device 10, the sealing device 10 (combination of the annular members 40 and 50) itself is plastically deformed by such a biting phenomenon, so that when setting the shape and size of the sealing device 10, a crushing allowance is obtained. There is no need to provide Therefore, the sealability can be improved, and it can be used for a long period of time under all kinds of motion conditions that require low sliding resistance such as rotation, reciprocating motion, swinging, etc. become.
[0022]
Further, in the sealing device 10 according to the present embodiment, the shape and size of the axial section of the first annular member 40 are substantially the same as those obtained by rotating the axial section of the second annular member 50 by 180 degrees.
[0023]
For this reason, even when fluid pressure is applied to either of the first annular member 40 and the second annular member 50 along the axial direction, the same sealing performance is provided in the annular gap between the shaft member 20 and the outer member 30. Can be guaranteed.
[0024]
Here, the tapered peripheral surface 43 of the first annular member 40 and the tapered peripheral surface 53 of the second annular member 50 face each other to form a contact surface 43A (53A), and the contact surface 43A (53A). ) And the axial length H2 of the tapered peripheral surface 43 of the first annular member 40 have a relationship of “H1 ≧ (１ ／) × H2”, and It is preferable that the taper angle θ of the tapered peripheral surface 43 of the annular member 40 and the tapered peripheral surface 53A of the second annular member 53 be set to 45 ° or less.
[0025]
According to the configuration, high sealing performance is ensured when the applied fluid pressures P1 and P2 act individually or when the fluid pressure P1 and the fluid pressure P2 act simultaneously. Even when the pressure P1 and the fluid pressure P2 act alternately (alternating action), at the moment when the fluid pressure is switched from the fluid pressure P1 (P2) to the fluid pressure P2 (P1), the first annular member 40 and the second annular member 50 Since the shape after the plastic deformation is stably held by the biting phenomenon of, high sealing performance can be secured.
[0026]
In addition, the axial length H1 of the contact surface and the axial length H2 of the tapered peripheral surface of the first annular member are represented by “(2/3) × H2 ≧ H1 ≧ (1/3) × H2 And the taper angle θ of the contact surface 43A (53A) is more preferably 30 ° or more and 60 ° or less.
[0027]
According to the configuration, it is possible to ensure a high sealing performance when the applied fluid pressure P1 and the fluid pressure P2 individually act on or when the fluid pressure P1 and the fluid pressure P2 act simultaneously. Even when the pressure P1 and the fluid pressure P2 act alternately (alternating action), at the moment when the fluid pressure is switched from the fluid pressure P1 (P2) to the fluid pressure P2 (P1), the first annular member 40 and the second annular member 50 In addition to the effect that the shape after deformation is stably maintained by the biting phenomenon, the shape stability and durability during long-term use are achieved at the same time, and the sealing performance is further improved. .
[0028]
In addition to the description in the present embodiment, the sealing device 10 can be used in various modes.
[0029]
(Second embodiment)
For example, as shown in FIG. 3A, two annular grooves 23 and 24 are arranged in the outer peripheral surface of the shaft member 20 along the axial direction, and the sealing device 10 is mounted on one of the annular grooves 23 and the other is installed. Another sealing device 60 such as a rubber-like elastic body (packing: rubber is used in the present embodiment) can be attached to the annular groove. According to such a structure, the sealing device 10 cuts the fluid pressure (P10) applied from the left side in the drawing, thereby effectively reducing the burden on the other sealing devices 60.
[0030]
(Third embodiment)
Further, as shown in FIG. 3B, the sealing device 10 and another sealing device 60 can be mounted side by side in one annular groove 25 provided on the outer peripheral surface of the shaft member 20. According to such a structure, the sealing device 10 cuts the fluid pressure (P10) applied from the left side in the figure along the axial direction, and effectively reduces the load on the other sealing devices 60. It also functions as a backup ring for preventing the other sealing device 60 from protruding.
[0031]
(Fourth embodiment)
As shown in FIG. 3 (c), three annular grooves 26, 27, 28 are provided along the axial direction on the outer peripheral surface of the shaft member 20, and the sealing device 10 is inserted into the annular grooves 26, 28 on both sides. It is also possible to mount another annular sealing device 60 in the central annular groove 27. According to such a structure, the sealing device 10 cuts the fluid pressure (P30, P40) applied from any side along the axial direction, and effectively reduces the burden on the other sealing devices 60. .
[0032]
(Fifth embodiment)
Further, as shown in FIG. 3D, in one annular groove 29 provided on the outer peripheral surface of the shaft member 20, another sealing device 60 may be arranged so as to be sandwiched between the two sealing devices 10. it can. According to such a structure, the sealing device 10 cuts the fluid pressure (P50, P60) applied from any side along the axial direction, thereby effectively reducing the burden on the other sealing devices 60. In addition to the reduction, the sealing device 60 also functions as a backup ring for preventing the sealing device 60 from protruding.
[0033]
Note that, as in the first embodiment (FIGS. 1 and 2), the second embodiment (FIG. 3A), and the fourth embodiment (FIG. 3C), the sealing device 10 It is more advantageous to house the sealing device 60 and the other sealing device 60 in separate annular grooves in terms of suppressing wear and deformation due to mutual interference and deterioration in sealing performance due to deformation. However, the third embodiment (FIG. 3 (b)) and the fifth embodiment (FIG. 3 (d)) in terms of making the mounting space of the sealing device 10 and the other sealing device 60 compact. As described above, the advantage that the structure in which the sealing device 10 and the other sealing device 60 are housed in one annular groove is recognized.
[0034]
Further, in the sealing device 10 according to each of the above-described embodiments, when a fluid pressure is externally applied to the sealing device 10 itself along the axial direction, the shaft member 20 and the outer shell member 30 move relative to each other along the axial direction. When the shaft member 20 and the outer member 30 make relatively different rotational movements along the direction around the axis, the shaft member 20 and the outer member 30 move in the other direction along the direction around the axis. The sealing performance is exhibited in any of the swinging motions with respect to the member (20 or 30). That is, in the gap between the shaft member 20 and the outer shell member 30, the fluid pressure applied from one direction or both directions along the axial direction, or the fluid pressure applied alternately from both, is mounted at the mounting site of the sealing device 10. It is possible to seal effectively from the beginning to the long term.
[0035]
In addition, the sealing device 10 according to each of the above-described embodiments is configured such that the gap between the shaft member 20 and the outer shell member 30 having the cylindrical inner circumferential surface 31 surrounding the outer circumferential surface 21 of the shaft member 20 is reduced. It is arranged in an annular groove 22 formed on the outer peripheral surface 21 and seals a gap (annular gap) between the shaft member 20 and the outer shell member 30. On the other hand, in the sealing device of the present invention, the annular groove formed in the inner peripheral surface of the outer member in the gap between the shaft member and the outer member having a cylindrical inner peripheral surface surrounding the outer peripheral surface of the shaft member. , And can easily be embodied as an embodiment for sealing the gap (annular gap) between the shaft member and the outer shell member.
[0036]
【The invention's effect】
According to the present invention, from the initial stage of use of the object to be sealed by the sealing device, that is, from the initial stage of use of the device including the shaft member and the outer shell member, the first annular member bites into the gap of the inner edge portion of the tapered peripheral surface, The annular member cuts into the outer edge of the tapered peripheral surface. Due to this biting phenomenon, even in an environment where a low-strength material such as rubber cannot be used, in the annular gap between the shaft member and the outer member, it is possible to stably obtain a high sealing property for a long period from the initial stage of mounting. it can.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a partial cross section of a sealing device according to an embodiment of the present invention.
FIG. 2 is a schematic view showing the operation of the sealing device according to the embodiment;
FIG. 3 is a schematic diagram illustrating the operation of a sealing device according to another embodiment.
FIG. 4 is a schematic view showing a partial cross section of an example of a conventional sealing device.
FIG. 5 is a schematic view showing a partial cross section of an example of a conventional sealing device.
FIG. 6 is a schematic view showing a partial cross section of an example of a conventional sealing device.
[Explanation of symbols]
Reference Signs List 10 sealing device 20 shaft member 21 outer peripheral surface 22 annular groove 30 outer member 31 inner peripheral surface 40 first annular member 41 outer peripheral surface 42 inner peripheral surface 43 tapered peripheral surface (tapered surface)
43A Part of tapered peripheral surface (contact surface)
44 End surface 50 Second annular member 51 Inner peripheral surface 52 Outer peripheral surface 53 Tapered peripheral surface 53A Part of tapered peripheral surface (contact surface)
54 End surface H1 Axial length H2 of the contact surface between the first annular member and the second annular member H2 Axial length S1, S2 of the tapered peripheral surface of the first annular member Gap θ Taper angle

Claims (1)

A sealing device mounted in an annular groove provided in one of the outer shell member and the shaft member to seal an annular gap between the outer shell member and a shaft member mounted in a cylindrical hole of the outer shell member,
A first annular member having high rigidity, and a second annular member having high rigidity disposed in contact with the first annular member,
At the contact portion between the first annular member and the second annular member, between the outer peripheral surface and the sealing surface of the first annular member and between the inner peripheral surface and the sealing surface of the second annular member. A sealing device having a gap.

Images