JP2005265161A - Seal for fuel injection pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seal for a fuel injection pump capable of being easily attached to an annular space, and further improving the performance of a resin seal. <P>SOLUTION: This seal for the fuel injection pump seals the annular space between an housing and a shaft relatively movably assembled together, and comprises an oil seal 10 comprising a rubber elastic body oil seal lip 14 fitted in the housing, of which the tip of inner periphery part is slid on the shaft; and the resin seal 20 located at a sealed fluid side of the oil seal 10, attaching to the inner periphery of the oil seal 10 and comprising a resin seal lip 23 made of PTFE in which a tip part 23b sliding on the shaft inclines toward the sealed fluid side. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel injection pump seal that seals an annular space formed between two relatively movable members.

  Conventionally, an oil seal having only one oil seal lip made of a rubber-like elastic body has been used as a fuel injection pump seal. When sealing fluid is sealed with the oil seal lip made of rubber-like elastic material, pressure from the pressure fluid is directly applied to the oil seal lip, so that the oil seal lip is deformed by the increase in pressure and the shaft and the oil seal lip slide. There was a problem that oil leakage occurred from the surface. In addition, since the rubber seal elastic material with high rigidity is used as the material of the oil seal lip to withstand the pressure from the sealing fluid, the elastic properties of the oil seal lip are not fully exhibited under low temperature conditions, and it can follow the eccentricity of the shaft. There was a problem that oil leakage occurred even at low pressure.

  As a countermeasure against this, Patent Document 1 below discloses an invention in which two oil seal lips of rubber-like elastic bodies are provided. Further, as shown in FIG. 4, a high-rigidity resin seal 103 is attached to the sealing fluid side A of the oil seal 101 separately from the oil seal 101, and the pressure of the high-pressure fluid is received by the high-rigidity resin seal lip 104. It was carried out. As a result, the pressure applied to the oil seal lip 102 of the oil seal 101 formed of the rubber-like elastic body is reduced, so that the rigidity of the oil seal lip 102 can be lowered and the material of the rubber-like elastic body can be made rigid. In order to prevent oil leakage, the oil seal lip 102 is secured to follow the shaft eccentricity.

  However, it is necessary to mount two parts, an oil seal and a resin seal, when mounting in the annular space, and there is a problem that the mounting work becomes complicated. To solve this problem, Patent Document 2 below Has proposed a device in which an oil seal and a resin seal are integrated. However, the material and shape for further improving the performance of the resin seal have not been disclosed.

Japanese Patent Laid-Open No. 08-068370 No. 05-003819

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a fuel injection pump seal that is easy to assemble in an annular space and further improves the performance of a resin seal. To do.

  In order to achieve the above object, a fuel injection pump seal according to claim 1 of the present invention seals an annular space between two members assembled so as to be relatively movable with respect to each other. An oil seal having a rubber-like elastic seal lip whose tip of the peripheral part slides on another member, and a tip that is positioned on the sealing fluid side of the oil seal and closely contacts the inner periphery of the oil seal and slides on another member And a resin seal having a PTFE resin seal lip inclined toward the sealing fluid side.

  The present invention has the following effects.

  That is, in the sealing device of the present invention having the above-described configuration, PTFE (polytetrafluoroethylene) is used as the material of the resin seal lip, so that the pressure resistance at low temperature is improved, and the pressure of the sealing fluid at low temperature is increased. Even if it is high, it is possible to handle the pressure with the resin seal lip, the pressure applied to the seal lip of the oil seal formed of a rubber-like elastic body can be reduced, and oil leakage can be prevented. . In addition, since the tip of the resin seal lip is inclined toward the sealing fluid side, even if the pressure from the sealing fluid is high, the resin seal lip takes over the pressure of the sealing fluid without deformation. It is possible to reduce the pressure applied to the seal lip of the oil seal formed of the elastic body, and to prevent oil leakage.

  Preferred embodiments of the present invention will be described below with reference to the drawings. However, the scope of the present invention is not intended to be limited to the contents described in this embodiment unless otherwise specified.

  FIG. 1 shows a cross section of a main part of a seal 1 for a fuel injection pump according to a first embodiment of the present invention, which is configured as follows.

  This fuel injection pump seal 1 is mounted in an annular space formed by a housing and a shaft (not shown) which are two members assembled concentrically, and seals so that the sealing fluid does not leak to the atmosphere side B. The seal 10 and the resin seal 20 are in close contact with the inner periphery of the oil seal 10.

  The oil seal 10 includes a core 11 formed of a cylindrical portion 11a formed along the housing, and a flange 11b extending from one end on the atmosphere side B of the cylindrical portion 11a toward the inner periphery in the axial direction, and the outer periphery of the core 11 Fixed sealing part 12 of rubber-like elastic body vulcanized and bonded to the side and inner peripheral side, oil seal lip 14 located on the sealing fluid side A integrally formed with the fixed sealing part 12 and sliding on the shaft, and the atmosphere side Dust seal lip 15 located in B and rubber-like elastic seal lip 13 having two seal lips, and a lip edge attached to a recess formed on the outer periphery opposite to the lip edge of oil seal lip 14 And a garter spring 16 for applying a tightening force.

  The resin seal 20 includes a cylindrical portion 21a that is in close contact with the inner surface of the inner peripheral portion 12a of the fixed sealing portion 12, and a flange portion 21b that extends from one end of the sealed fluid side A of the cylindrical portion 21a toward the inner periphery in the axial direction. It consists of a single metal ring 21, a cylindrical portion 22a that is in close contact with the inner surface of the cylindrical portion 21a of the first metal ring 21, and a flange portion 22b that extends from one end of the sealed fluid side A of the cylindrical portion 22a toward the inner periphery in the axial direction. The outer peripheral portion 23a sandwiched between the second metal ring 22, the flange portion 21b of the first metal ring 21 and the flange portion 22b of the second metal ring 22, and the tip portion 23b inclined toward the sealing fluid side A And a PTFE resin seal lip 23.

  FIG. 2 shows another embodiment 2 of the present invention. The oil seal 1 has the same configuration as that of the first embodiment, and the configuration of the resin seal 20 is different. The resin seal 20 includes a cylindrical portion 21a that is in close contact with the inner surface of the inner peripheral portion 12a of the fixed sealing portion 12, and a flange portion 21b that extends from one end of the sealed fluid side A of the cylindrical portion 21a toward the inner periphery in the axial direction. The resin seal lip 23 of PTFE which consists of the one metal ring 21, the outer peripheral part 23a, and the front-end | tip part 23b which inclines toward the sealing object side, and the front-end | tip part of the flange part 21b of the 1st metal ring 21 is covered and resin. And a rubber-like elastic coupling member 24 interposed between the outer peripheral portion 23a of the seal lip 23 and the sealed fluid side A and tightly coupling the flange portion 21b and the outer peripheral portion 23a.

  Accordingly, since the pressure from the sealing fluid is borne by the resin seal 20 located on the sealing fluid side A with respect to the oil seal 10, the pressure applied to the oil seal lip 14 of the oil seal 10 is reduced, and the rubber-like elasticity of the oil seal lip 14 is reduced. It is possible to employ a material having a reduced body rigidity, thereby improving the sealing performance against the object to be sealed. In particular, since the resin seal lip 23 is made of PTFE, the pressure resistance of the resin lip at low temperatures is improved, and the sealability of the oil seal lip 14 of the oil seal 10 at low temperatures is ensured.

FIG. 3 shows a change in pressure limit with respect to a change in temperature when PTFE is used as the material of the resin seal lip 23 as compared with a conventional product, and an improvement in pressure resistance at a low temperature is recognized. The test conditions are as follows.
Shaft eccentricity: 0.05mm TIR
Mounting eccentricity: 0.1mm TIR
Oil type, oil amount, kerosene, full rotation speed 3000rpm
Oil temperature: -10 to -35 ° C
Pressure .... until interference occurs. ... (lower limit) -0.1mm

  Further, since the shape of the resin seal lip 23 is inclined toward the sealing fluid side A, the shape of the resin seal lip 23 is not deformed even when the sealing fluid pressure is high. The reduction in pressure applied to the ten oil seal lips 14 can be maintained.

  Furthermore, in Example 2, since the outer peripheral portion 23a of the resin seal lip 23 is vulcanized and bonded to the flange portion 21b of the first metal ring 21 via the coupling member 24, the second metal ring 22 is not required and is lightweight. The assembly of the resin seal 20 to the oil seal 10 is facilitated.

Sectional drawing of the seal for fuel pumps based on Example 1 of this invention. Sectional drawing of the seal for fuel pumps based on Example 2 of this invention Low temperature pressure resistance limit confirmation test result when using PTFE Sectional view of oil seal and resin seal according to conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel injection pump seal 10 Oil seal 11 Core metal 11a, 21a, 22a Cylindrical part 11b, 21b, 22b Flange part 12 Fixed close contact part 13 Seal lip part 14, 15 Seal lip 16 Garter spring 20 Resin seal 21 First metal ring 22 Second metal ring 23 Resin seal lip 23a Outer peripheral part 23b Tip part 24 Coupling member A Sealing fluid side B Atmosphere side

Claims (1)

  An oil having a rubber-like elastic seal lip that seals an annular space between two members that are assembled so as to be movable relative to each other, and that fits into one member and has a tip of an inner peripheral portion that slides on another member. A resin seal having a PTFE resin seal lip which is positioned closer to the sealing fluid side than the oil seal, is in close contact with the inner periphery of the oil seal, and is slanted toward the sealing fluid side with a tip portion which slides on another member; A fuel injection pump seal comprising:

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