JP2014173690A - Packing for injector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packing for an injector which seals a space between an injector for jetting a fuel and a housing including a hole in which the injector is inserted and solves problems such as increase of insertion resistance and protruding of the packing.SOLUTION: An outer peripheral surface of a packing includes a round part between first and second taper parts and closely contacts with a cylindrical wall of a second step part at the housing side. An inner peripheral surface of the packing includes a round part between third and fourth taper parts and closely contacts with a cylindrical wall of a first step part at the injector side. An angle β formed between the third and fourth taper parts is set larger than an angle α formed between the first and second taper parts.

Description

  The present invention relates to a packing according to a sealing technique, and more particularly to a packing suitable for use in an injector.

  Conventionally, an injector 51 shown in FIG. 3 is known, and this injector 51 supplies hydrogen gas as fuel to, for example, a fuel cell power generator mounted on a fuel cell vehicle. The injector 51 has a structure that is inserted into a hole 62 provided in the housing 61, and a gasket 71 for preventing fuel leakage is attached between the injector 51 and the housing 61.

  The packing 71 is mounted between a stepped portion 53 provided on the outer peripheral portion of the injector 51 and a stepped portion 63 provided on the inner periphery of the hole portion 62 of the housing 61. That is, a first step portion 53 is provided on the outer peripheral portion of the injector 51. The first step portion 53 is a combination of a cylindrical wall 53a and an end wall 53b extending radially outward from one axial end of the cylindrical wall 53a. In addition, a second step portion comprising a combination of a cylindrical wall 63a and an end wall 63b extending radially inward from the other axial end of the cylindrical wall 63a on the inner periphery of the hole 62 of the housing 61. 63 is provided, and an annular space portion is set so as to be surrounded by both step portions 53 and 54, and packing 71 is attached to this space portion.

  The packing 71 is a square ring having a rectangular cross section as shown in the figure, or a ring having a shape in which the outer peripheral corner 72 of the square ring is obliquely cut as shown in FIG. In the packing 71 having such a shape, the inner and outer circumferential directions (radial direction) are usually set to have no crushing allowance depending on tolerances. In this case, the packing 71 is deformed by the pressure of fuel from above, Sealing is achieved by generating surface pressure on the inner and outer periphery. Therefore, in order to maintain the sealing function regardless of the pressure of the fuel, it is necessary to provide a crushing margin on the outer peripheral side, so that the filling rate of the packing 71 with respect to the space portion increases, and therefore when the packing 71 is mounted. There is a problem that the insertion resistance increases. Further, when the filling rate is large as described above, there is a problem that the packing 71 is damaged by protruding into the gap 81 between the injector 51 and the housing 61 as shown in FIG.

JP 2010-261317 A

  In view of the above points, an object of the present invention is to provide an injector packing that can suppress and eliminate the problem of increased insertion resistance and the problem of sticking out of the packing.

  In order to achieve the above object, an injector packing according to claim 1 of the present invention is an injector packing for sealing between an injector for injecting fuel and a housing having a hole for inserting the injector. Has a first step portion formed of a combination of a cylindrical wall and an end face wall extending radially outward from one axial end of the cylindrical wall on the outer periphery, and the housing has a hole in the hole. A second step portion comprising a combination of a cylindrical wall and an end wall extending radially inward from the other axial end portion of the cylindrical wall on the periphery, and the packing is provided at the two step portions; In the packing for an injector mounted in the enclosed annular space, the outer diameter of the outer peripheral surface of the packing gradually decreases from the axial center to one axial end. A first taper portion in a direction to be reduced to the second taper portion, a second taper portion in which the outer diameter dimension is gradually reduced from the central portion in the axial direction to the other end portion in the axial direction, and the two taper portions. A rounded arc-shaped rounded portion, and when mounted, the rounded portion is in close contact with the cylindrical wall of the second stepped portion, and the inner peripheral surface of the packing is axially spaced from the axially central portion. A third taper portion in which the inner diameter dimension gradually increases toward the end portion, a fourth taper portion in which the inner diameter dimension gradually increases from the axial center portion to the other end portion in the axial direction, An arc-shaped round section set between both tapered sections, and when mounted, the round section is in close contact with the cylindrical wall of the first step section, and an angle formed by the first and second tapered sections Where α is α and β is the angle formed by the third and fourth tapered portions, satisfying the relationship α <β It is characterized by doing.

  In the packing for an injector according to claim 2 of the present invention, in the packing according to claim 1, α is an angle of 100 degrees or more and 140 degrees or less, and β is an angle of 160 degrees or more and less than 180 degrees. It is characterized by.

  In the injector packing of the present invention having the above-described configuration, the outer peripheral surface of the packing includes a rounded portion between the first and second tapered portions, and the rounded portion is in close contact with the cylindrical wall of the second step portion on the housing side. Therefore, it is possible to seal between the housing and the inner peripheral surface of the packing is provided with a rounded portion between the third and fourth tapered portions, and this rounded portion serves as the first step portion on the injector side. In close contact with the cylindrical wall, it is possible to seal between the injectors.

  In addition, after the sealing function is ensured in this way, the first and second tapered portions having a shape gradually retreating radially inward from the rounded portion located at the outermost periphery are provided and located at the innermost periphery. Since the third and fourth tapered portions having a shape gradually retreating radially outward from the rounded portion are provided, the packing rate of the packing is set to be small compared with the conventional rectangular shape.

  Therefore, the packing has a small filling rate, and the outer peripheral surface of the packing is provided with a taper portion in which the outer diameter dimension gradually decreases from the axial center to the axial end. Insertion resistance to the step is small and easy to insert.

  In addition, the packing has a small filling rate, and the inner peripheral surface of the packing has a tapered portion in which the inner diameter dimension gradually increases from the axial center to the axial end, so the packing is between the injector and the housing. It is difficult for the gaps to protrude and damage.

  The angle α formed by the first and second tapered portions on the outer peripheral surface of the packing and the angle β formed by the third and fourth tapered portions on the inner peripheral surface of the packing may be equal to each other, but the first and second on the outer peripheral surface of the packing may be the same. If the angle β formed by the third and fourth taper portions on the inner circumferential surface of the packing is set larger than the angle α formed by the taper portion, when the packing is inserted into the housing side ahead of the injector side, the packing is It becomes difficult to fall.

  According to the result of the prototype test conducted by the inventors of the present application, the angle α formed by the first and second taper portions on the outer circumferential surface of the packing is less than 100 degrees, which is a sharp tip, and when it is larger than 140 degrees, an appropriate sealing surface If the pressure does not rise and the seal surface pressure is forced to rise, the filling rate increases. Therefore, it is preferable that the angle α formed by the first and second tapered portions on the outer circumferential surface of the packing be 100 degrees or more and 140 degrees or less. Further, the angle β formed by the third and fourth tapered portions on the packing inner peripheral surface is preferably set to an angle of 160 degrees or more and less than 180 degrees in order to prevent the above-described packing from toppling.

  The present invention has the following effects.

  That is, in the present invention having the above-described configuration, the outer peripheral surface of the packing is in close contact with the cylindrical wall of the second stepped portion on the housing side with the rounded portion, and the inner peripheral surface of the packing also has the rounded portion and the first stepped portion on the injector side. While maintaining the sealing function at the inner and outer circumferences by closely contacting the cylindrical wall, and by providing each taper portion, and the packing filling rate is set low accordingly, the insertion resistance can be reduced, The protrusion of the packing can be suppressed. Moreover, since there are few parts which a packing contacts a housing or an injector by providing each taper part, a seal surface pressure can be set high. In addition, since the angle β formed by the third and fourth taper portions on the packing inner peripheral surface is set larger than the angle α formed by the first and second taper portions on the packing outer peripheral surface, the packing may be overturned during insertion. Can be suppressed.

Sectional drawing of the principal part of the packing which concerns on the Example of this invention Perspective view of the packing Sectional drawing of the injector which concerns on a prior art example, and the packing attached to this Cross-sectional view of main parts of a packing according to another conventional example Sectional view showing the state of failure caused by the packing

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a cross section of the main part of a packing 11 according to an embodiment of the present invention. FIG. 2 shows a perspective view of the packing 11.

  As shown in FIG. 1, the packing 11 according to this embodiment is mounted to seal fuel between an injector 51 that injects fuel and a housing 61 that includes a hole 62 into which the injector 51 is inserted. The packing 11 according to this embodiment is mounted between an annular step 53 provided on the outer periphery of the injector 51 and an annular step 63 provided on the inner periphery of the hole 62 of the housing 61. That is, the first is formed by a combination of a cylindrical wall 53a and an end wall 53b extending radially outward from one axial end (upper end in the figure) of the cylindrical wall 53a on the outer periphery of the injector 51. A stepped portion 53 is provided, and extends radially inward from the cylindrical wall 63a and the other axial end (lower end in the figure) of the cylindrical wall 63a on the inner periphery of the hole 62 of the housing 61. The second step portion 63 made of the combination of the end face walls 63b is provided, and an annular space portion is set so as to be surrounded by the first and second step portions 53 and 54, so that the packing 11 is attached to the space portion. Is done.

  The packing 11 is not a square ring having a rectangular cross section, but is configured as follows.

  That is, the packing 11 is formed in a ring shape by a predetermined rubber-like elastic body, and includes four surfaces, an outer peripheral surface 21, an inner peripheral surface 31, and both axial end surfaces 41.

Of these four surfaces, the outer peripheral surface 21 of the packing 11 is a first taper portion whose outer diameter dimension gradually decreases from the axial central portion 21a to one axial end portion (upper end portion in the figure). 22 and a second taper portion 23 whose outer diameter is gradually reduced from the axial center portion 21a to the other axial end portion (the lower end portion in the figure), and the two taper portions 22 and 23. And a rounded arc-shaped rounded portion (first rounded portion) 24. Since the maximum outer diameter dimension d ₁ of the rounded portion 24 is set to be larger than the inner diameter dimension d ₂ of the cylindrical wall 63 a of the second stepped portion 63 on the housing 61 side, the rounded portion 24 includes a tube of the second stepped portion 63. The crushing allowance for the shaped wall 63a is set, so that the rounded portion 24 comes into close contact with the cylindrical wall 63a of the second stepped portion 63 when mounted. The first and second tapered portions 22 and 23 are each formed in a linear cross section, and an angle (intersection angle) α formed by both the tapered portions 22 and 23 is set to an angle of 100 degrees or more and 140 degrees or less.

The inner peripheral surface 31 of the packing 11 includes a third taper portion 32 having an inner diameter dimension gradually increasing from the axial center portion 31a to one end portion in the axial direction (upper end portion in the figure), and an axial center portion. A fourth taper portion 33 whose inner diameter dimension gradually increases from 31a to the other end portion in the axial direction (the lower end portion in the drawing), and an arc-shaped cross section set between both taper portions 32 and 33. Part (second round part) 34. Since the minimum inner diameter d ₃ of the rounded section 34 is set equal to or substantially equal to the outer diameter d ₄ of the cylindrical wall 53a of the first step portion 53 of the injector 51 side, here initial squeeze is Although not set, as described above, when the packing 11 is elastically deformed at the time of mounting due to the crushing margin set on the outer peripheral surface 21 side, the minimum inner diameter dimension of the rounded portion 34 is reduced. It is in close contact with the cylindrical portion 53a. The third and fourth tapered portions 32 and 33 are each formed in a linear cross section, and an angle (intersection angle) β formed by both the tapered portions 32 and 33 is set to an angle of 160 degrees or more and less than 180 degrees.

  Both end surfaces 41 in the axial direction of the packing 11 are each formed into a planar shape perpendicular to the axis.

Further, the packing 11 further includes the following configuration.
(A) Four corners in the cross-sectional shape of the packing 11, that is, a corner between the outer peripheral surface 21 and one end surface 41 in the axial direction, a corner between the outer peripheral surface 21 and the other end surface 41 in the axial direction, and an inner peripheral surface 31 and one in the axial direction. A chamfered portion 42 having an arcuate cross section is provided at each of the corners of the end surface 41 and the corners of the inner peripheral surface 31 and the other axially end surface 41.
(B) The cross-sectional shape of the packing 11 is a shape (axisymmetric shape) symmetrical in the axial direction as a whole. Therefore, the inclination angles of the first and second taper portions 22 and 23 are set to be equal to each other, and the inclination angles of the third and fourth taper portions 32 and 33 are also set to be equal to each other.
(C) As described above, the angle α formed by the first and second tapered portions 22 and 23 is set to an angle of 100 degrees or more and 140 degrees or less, and the angle β formed by the third and fourth tapered portions 32 and 33 is 160. Since the angle is set to be greater than or equal to 180 degrees and smaller than 180 degrees, when both angles are compared, the angle β formed by the third and fourth tapered portions 32 and 33 is larger than the angle α formed by the first and second tapered portions 22 and 23. Is set larger.
(D) The minimum outer diameter dimension of the outer peripheral surface 21 of the packing 11, that is, the minimum inner diameter dimension of the first and second tapered portions 22 and 23, is the inner diameter dimension d ₂ of the cylindrical wall 63a of the second step portion 63 on the housing 61 side. It is set smaller. Therefore, when the packing 11 is mounted, a radial gap is formed between the first and second tapered portions 22 and 23 and the cylindrical wall 63a of the second step portion 63.
(E) The maximum inner diameter dimension of the inner peripheral surface 31 of the packing 11, that is, the maximum inner diameter dimension of the third and fourth tapered portions 32, 33 is the outer diameter dimension d of the cylindrical wall 53a of the first step portion 53 on the injector 51 side. It is set to be larger than ₄ . Therefore, when the packing 11 is mounted, a radial gap is formed between the third and fourth tapered portions 32 and 33 and the cylindrical wall 53 a of the first step portion 53.

  In the packing 11 having the above-described configuration, the outer peripheral surface 21 of the packing 11 includes a rounded portion 24 between the first and second tapered portions 22 and 23, and the cylindrical portion of the second stepped portion 63 on the housing 61 side with the rounded portion 24. In order to be in close contact with the wall 63a, it is possible to seal between the housing 61 and the inner peripheral surface 31 of the packing 11 is provided with a rounded portion 34 between the third and fourth tapered portions 32, 33. Since the portion 34 is in close contact with the cylindrical wall 53a of the first step portion 53 on the injector 51 side, the space between the injector 51 can be sealed. Therefore, the packing 11 exhibits a sufficient sealing function.

  In addition, the first and second taper portions 22 and 23 having a shape gradually retreating radially inward from the rounded portion 24 located on the outermost periphery are provided while the sealing function is ensured as described above. Since the third and fourth tapered portions 32 and 33 having a shape gradually retreating radially outward from the rounded round portion 34 are provided, the packing 11 has a smaller filling rate than the conventional rectangular cross section. Is set.

  Therefore, the packing 11 has a small filling rate, and the outer peripheral surface 21 of the packing 11 includes a second taper portion 23 whose outer diameter dimension gradually decreases from the axial center portion 21a to the other axial end portion. Therefore, the packing 11 has a small insertion resistance with respect to the second step portion 63 on the housing 61 side, and is easy to insert.

  Further, the packing 11 has a small filling rate, and the inner peripheral surface 31 of the packing 11 includes a fourth taper portion 33 whose inner diameter dimension gradually increases from the axial center portion 31a to the other axial end portion. Therefore, the packing 11 is unlikely to protrude from the gap 81 between the injector 51 and the housing 61 and is not easily damaged.

  Therefore, according to the intended purpose of the present invention, it is possible to provide an injector packing that can suppress and eliminate the problem that the insertion resistance increases and the problem that the packing protrudes.

  Further, the angle β formed by the third and fourth tapered portions 32 and 33 on the inner peripheral surface 31 of the packing 11 is larger than the angle α formed by the first and second tapered portions 22 and 23 on the outer peripheral surface 21 of the packing 11. Therefore, when the packing 11 is inserted into the housing 61 side in advance of the injector 51, the packing 11 can be prevented from falling (twisting).

DESCRIPTION OF SYMBOLS 11 Packing 21 Outer peripheral surface 21a, 31a Axial direction center part 22 1st taper part 23 2nd taper part 24, 34 R part 31 Inner peripheral surface 32 3rd taper part 33 4th taper part 41 Axial end face 42 Chamfer 51 Injector 53 1st step part 53a, 63a Cylindrical wall 53b, 63b End surface wall 61 Housing 62 Hole part 63 2nd step part 81 Crevice

Claims (2)

An injector packing that seals between an injector for injecting fuel and a housing having a hole for inserting the injector, wherein the injector has a cylindrical wall at an outer peripheral portion thereof and one end in an axial direction of the cylindrical wall. A first step portion comprising a combination of end face walls extending radially outward from the portion, and the housing has a cylindrical wall on the inner periphery of the hole and a diameter from the other axial end portion of the cylindrical wall. Injector packing provided with a second step portion comprising a combination of end face walls extending inward in the direction, the packing being mounted in an annular space surrounded by the two step portions,
The outer peripheral surface of the packing has a first taper portion whose outer diameter is gradually reduced from the axial center portion to one axial end portion, and the other axial end portion from the axial central portion. A second taper portion whose outer diameter is gradually reduced toward the outer periphery, and a round portion having an arcuate cross section set between the two taper portions. Close to the cylindrical wall of the
The inner peripheral surface of the packing has a third taper portion whose inner diameter dimension gradually increases from the axial center portion to one axial end portion, and the axial central portion to the other axial end portion. A fourth taper portion whose inner diameter dimension is gradually increased over time, and an arcuate section having an arcuate cross section set between the two taper portions. Close to the cylindrical wall,
An injector packing characterized by satisfying a relationship of α <β, where α is an angle formed by the first and second tapered portions, and β is an angle formed by the third and fourth tapered portions. The packing according to claim 1,
α is an angle of 100 ° to 140 °, and β is an angle of 160 ° to less than 180 °.

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