JP3192572U - Valve stem seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an excessive stress generated at a fitting portion with a valve stem guide at the time of mounting on the valve stem guide, prevent an abnormality in the mounting state, and prevent loosening and falling off. Provide a valve stem seal that can be used. A valve stem seal 1 includes a substantially cylindrical holding portion 10 attached to a valve stem and made of a metal material, and a sealing portion 20 connected to the holding portion and made of an elastomer. The seal portion 20 is integrally formed with the seal lip 21, is arranged so as to cover the inner peripheral surface 11a of the tubular portion 11, and has an engaging portion 22 that engages with the outer peripheral surface of the valve stem guide. The engaging portion 22 has a low protrusion 23 that protrudes inward in the radial direction and has a low back surface 23a, and has a high back surface 24a that protrudes further inward in the radial direction from the low protrusion and is closer to the port side than the low protrusion 23. It has a high protrusion 24 provided and a stepped portion 25 provided between the low protrusion 23 and the high protrusion 24. [Selection diagram] Fig. 1

Description

  The present invention relates to a valve stem seal used for an internal combustion engine, and more particularly to a valve stem seal used for an engine valve of an internal combustion engine of an automobile or general industrial equipment.

  Conventionally, a valve stem seal of an internal combustion engine plays a role of preventing oil leakage from between the valve stem and the valve stem guide. On the other hand, in order to prevent excessive wear on the valve stem and the valve stem guide, it is necessary to supply an appropriate amount of oil to the sliding portion between the valve stem and the valve stem guide to lubricate the valve stem. In recent years, various efforts have been made to provide valve stem seals that meet these requirements.

  For example, as shown in FIG. 4, the conventional valve stem seal 100 includes a cylindrical base portion 120 attached to the outer periphery of the valve stem guide 110 and an upper end portion of the cylindrical base portion. A seal lip 130 and a back pressure lip 140 that are slidably in close contact with the surface, and a reinforcing sleeve 150 for holding them are provided.

  The cylindrical base 120, the seal lip 130, and the back pressure lip 140 are continuously formed of rubber-like elastic members, and are vulcanized and bonded to a metal reinforcing sleeve 150.

  A support protrusion 121 and a plurality of engagement protrusions 122 are provided on the inner peripheral surface of the cylindrical base portion 120. The engaging ridge 122 and the carrying ridge 121 are connected to each other via a trough 123. Further, the engaging ridge 122 and the carrying ridge 121 are formed at substantially the same height. On the outer peripheral surface of the valve stem guide 110, a plurality of engagement grooves 111 that are engaged with the respective engagement protrusions 122 are formed.

  In the valve stem seal 100, the cylindrical base 120 is supported on the outer peripheral surface of the valve stem guide 110 by forming the supporting protrusion 121. Further, the engagement between the engagement groove 111 and the engagement protrusion 122 prevents the valve stem seal 100 from coming off from the valve stem guide 110.

  Further, the valve stem seal 200 in FIG. 5 includes a lip portion 210 that seals a valve stem (not shown). The lip part 210 includes an oil lip 220 and a two-stage lip 230.

  The inner circumferential surface of the two-stage lip 230 is provided with a groove 240 that leads from the port B side to the oil A side. The groove 240 has a small groove width on the port B side and a large groove width on the oil A side. It has a shape. Thus, by forming the grooves 240 with different widths in the two-stage lip 230 in the axial direction, a certain amount of oil leakage is adjusted, and as a result, seizure between the valve stem and the valve stem guide is prevented. Further, below the lip portion 210, a ridge portion 250 and a groove portion 260 that are in contact with the outer peripheral surface of the valve stem guide are formed.

  However, when the conventional valve stem seal shown in FIG. 4 is mounted on the outer peripheral surface of the valve stem guide, a large deformation stress is generated in the fitting protrusion made of a rubber-like elastic material. It may be fixed in a deformed state. In addition, when the height of the fitting protrusion is increased in order to increase the fitting force, the tendency appears remarkably. If an abnormality occurs in the mounting state of the fitting protrusion, the fitting force generated between the fitting protrusion and the valve stem guide may be reduced. There was a limit to improving the resultant power.

  Further, in the other conventional valve stem seal shown in FIG. 5, it is only disclosed that a protruding portion that contacts the outer peripheral surface of the valve stem guide is provided. There is no disclosure about the action, and the same problem as described above will occur.

  The purpose of the present invention is to prevent excessive stress generated at the fitting position with the valve stem guide when mounted on the valve stem guide, to prevent abnormal mounting conditions, and to prevent loosening and dropping off. It is to provide a valve stem seal that can be made.

  In order to achieve the above object, a valve stem seal of the present invention is attached to a valve stem, a substantially cylindrical holding portion formed of a metal material, and a seal portion formed of an elastomer connected to the holding portion. The holding portion includes a cylindrical portion disposed so as to surround an outer peripheral surface of the valve stem guide, and a flange portion provided at an upper end of the cylindrical portion, The seal portion is a seal lip that contacts the outer peripheral surface of the valve stem, and is formed integrally with the seal lip and covers the inner peripheral surface of the tubular portion, and is engaged with the outer peripheral surface of the valve stem guide. An engaging portion, and the engaging portion protrudes radially inward and has a low back surface, and further protrudes radially inward from the low protrusion portion and has a high back surface, Port side than low protrusion Has a high projection portion provided, the a stepped portion provided between the high protrusion portion and the lower protrusion.

  The low back surface is provided substantially parallel to the outer peripheral surface of the valve stem guide.

  Moreover, the said step part has an inclined surface which connects the said low back surface and the said high back surface.

  Further, the valve stem guide is provided between a reduced diameter portion protruding outward in the radial direction, an enlarged diameter portion protruding further outward in the radial direction from the reduced diameter portion, and between the reduced diameter portion and the enlarged diameter portion. The stepped portion of the engaging portion is compression-fitted to the enlarged diameter portion of the valve stem guide, and the stepped portion of the engaging portion is the valve stem. Locked to the other stepped portion of the guide.

  Moreover, it is preferable that the said seal part has a back pressure lip formed in the end of the said seal lip, and slidably contact | abuts to the outer peripheral surface of the said valve stem.

  According to the present invention, the engagement portion of the seal portion that engages with the valve stem guide has a low protrusion portion having a low back surface, and protrudes from the low protrusion portion and has a high back surface, and more than the low protrusion portion. A high protrusion provided on the port side and a stepped portion provided between the low protrusion and the high protrusion. As a result, when the valve stem guide is attached to the valve stem guide, it is possible to appropriately elastically deform the low protrusion portion that is the fitting portion with the valve stem guide, and the low protrusion portion can be transformed into the valve stem guide with an appropriate deformation stress. It is compression fitted. As a result, it is possible to prevent excessive stress from being generated at the low protrusions, and to prevent an abnormal mounting state. Further, by providing the stepped portion between the low protrusion portion and the high protrusion portion, the stepped portion is reliably locked to the valve stem guide. Therefore, it is possible to easily attach the valve stem seal to the valve stem guide without excessively increasing the fitting force, and to prevent the valve stem seal from loosening or dropping from the valve stem guide. Can do. Further, even when external vibration or the like is received after mounting, it is possible to prevent the valve stem seal from being loosened or dropped for a long period of time.

  In addition, since the low back surface is provided approximately parallel to the axial direction of the valve stem guide, the pressure contact area between the low back surface of the low protrusion and the outer peripheral surface of the valve stem guide increases when mounted on the valve stem guide. Variation in the in-plane direction of the compressive stress generated at the protrusion can be suppressed.

  Furthermore, the stepped portion has an inclined surface that connects the low back surface and the high back surface. Thereby, the valve stem seal can be easily attached to the valve stem guide.

  Further, the valve stem guide has an enlarged diameter portion, a reduced diameter portion formed on the port side of the enlarged diameter portion, and another stepped portion provided between the enlarged diameter portion and the reduced diameter portion. The low protrusion portion of the engaging portion is compression-fitted to the enlarged diameter portion of the valve stem guide, and the stepped portion of the engaging portion is locked to the other stepped portion of the valve stem guide. That is, the low protrusion of the valve stem seal functions as a compression fitting portion, and the stepped portion of the valve stem seal functions as a locking portion. It is possible to reliably prevent the valve stem seal from loosening or falling off.

It is a longitudinal section showing roughly composition of a valve stem seal concerning an embodiment of the present invention. It is a longitudinal cross-sectional view which shows the state with which the valve stem seal of FIG. 1 is mounted | worn with a valve stem guide. It is an enlarged view of the high protrusion part and low protrusion part in FIG. It is a longitudinal cross-sectional view which shows the structure of the conventional valve stem seal. It is a longitudinal cross-sectional view which shows the structure of the other conventional valve stem seal.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a longitudinal sectional view schematically showing a configuration of a valve stem seal according to an embodiment of the present invention. This valve stem seal is used for an engine valve of an internal combustion engine, particularly an internal combustion engine of an automobile or general industrial equipment, and is intended to prevent oil leakage from between the valve stem and the valve stem guide. Attached to. Note that the valve stem seal of FIG. 1 shows an example, and the configuration of the valve stem seal according to the present invention is not limited to the form shown in FIG.

  The valve stem seal 1 includes a substantially cylindrical holding portion 10 made of a metal material, and a seal portion 20 connected to the holding portion and made of an elastomer. The valve stem seal 1 is a substantially cylindrical member. When the valve stem 50 (FIG. 2) is inserted into the cylindrical space, the inner peripheral portion of the seal portion 20 is caused by the elastic force of the garter spring 30. It abuts on the outer peripheral surface of the valve stem.

  The holding part 10 has a cylindrical part 11 disposed substantially coaxially with the valve stem 50, and a flange part 12 provided at the upper end of the cylindrical part, and its radial longitudinal section is substantially L-shaped. It is a type. The seal portion 20 is vulcanized and bonded to the holding portion 10 to join the holding portion 10 and the seal portion 20 together.

  The seal portion 20 includes a seal lip 21 that slidably contacts the outer peripheral surface 50a of the valve stem 50, and an engagement portion 22 that is engaged with the outer peripheral surface of the valve stem guide that is arranged substantially coaxially with the valve stem. These are integrally formed. A garter spring 30 is fitted on the outer peripheral surface of the seal lip 21, and the amount of oil supplied via the seal lip 21 is adjusted by the garter spring 30.

  The seal lip 21 has a substantially vertical V-shaped radial cross section, and a top portion of the seal lip 21 is slidably contacted with the outer peripheral surface 50a of the valve stem 50. The seal lip 21 has a main seal lip 21a that is in pressure contact with the outer peripheral surface 50a of the valve stem 50, and a sub seal lip 21b that is disposed on the port side of the main seal lip and contacts the outer peripheral surface 50a of the valve stem 50. doing.

  Further, the seal portion 20 has a back pressure lip 26 that is formed on the port side of the sub seal lip 21 b and is slidably brought into contact with the outer peripheral surface 50 a of the valve stem 50. The back pressure lip 26 blocks back pressure from the port side generated during operation so that the back pressure is not applied to the seal lip 21 through the gap between the valve stem 50 and the valve stem guide 40.

  The engaging portion 22 is disposed so as to cover the inner peripheral surface 11 a of the tubular portion 11. Specifically, the engaging portion 22 protrudes radially inward and has a low back surface 23a, and further protrudes radially inward from the low protrusion 23 and has a high back surface 24a. 11 has a high protrusion 24 provided on the port side of the low protrusion 23 and a stepped portion 25 provided between the low protrusion 23 and the high protrusion 24. Moreover, the low protrusion part 23 and the high protrusion part 24 are integrally formed without providing a trough part between these. Thereby, the low back surface 23a of the low protrusion part 23 is compression-fitted to the outer peripheral surface of the valve stem guide described later, and the stepped part 25 is locked to the stepped part of the valve stem guide described later.

  FIG. 2 is a longitudinal sectional view showing a state where the valve stem seal 1 of FIG. 1 is attached to the valve stem guide. In FIG. 2, as an example of the valve stem guide, a configuration in which a reduced diameter portion is provided on the port side and an enlarged diameter portion is provided on the upper portion is shown.

  As shown in FIG. 2, the valve stem guide 40 includes a reduced diameter portion 41 protruding outward in the radial direction, an enlarged diameter portion 42 protruding further outward in the radial direction from the reduced diameter portion 41, and the reduced diameter portion 41 and the increased diameter. It has a stepped portion 43 provided between the portion 42. When the valve stem seal 1 is attached to the valve stem guide 40, the low protrusion 23 of the engaging portion 22 is compression-fitted with an appropriate fitting force to the enlarged diameter portion 42 of the valve stem guide 40. At this time, the entire low back surface 23a of the low protrusion 23 is in pressure contact with the outer peripheral surface 42a of the enlarged diameter portion 42, and the low protrusion 23 is fixed on the outer peripheral surface 42a of the enlarged diameter portion 42 with a small amount of elastic deformation. The

  The low rear surface 23 a of the low protrusion 23 is provided substantially parallel to the axial direction of the valve stem guide 40. Thereby, when the low projection 23 is compression-fitted to the enlarged diameter portion 42 of the valve stem guide 40, the compressive stress generated in the low projection 23 can be made uniform. The high back surface 24a is preferably substantially parallel to the outer peripheral surface 41a of the valve stem guide 40. Thereby, when the valve stem seal 1 is mounted on the valve stem guide 40, the valve stem guide 40 can be easily inserted into the valve stem seal 1.

  Further, the stepped portion 25 located on the port side of the low protrusion 23 is locked to the stepped portion 43 located on the port side of the enlarged diameter portion 42 in the valve stem guide 40. In the present embodiment, a flat surface 43 a formed along the radial direction is provided on the port side of the enlarged diameter portion 42 of the valve stem guide 40, and the flat surface 43 a is a stepped portion in the valve stem seal 1. 25 abuts against the surface 25a of the high protrusion 25, that is, the side surface of the high protrusion 24 (FIG. 3). At this time, the high protrusion 24 is positioned in the axial direction at a position where it contacts the flat surface 43a. As a result, the valve stem seal 1 is accurately positioned with respect to the valve stem guide 40 and is prevented from coming off from the valve stem guide 40.

  The surface 25a of the stepped portion 25 is an inclined surface that is connected to the low back surface 23a at an obtuse angle α (FIG. 3). Accordingly, when the valve stem seal 1 is mounted on the valve stem guide 40, the corner portion 44 of the enlarged diameter portion 42 moves while being pressed on the inclined surface, so that the valve stem seal 1 can be easily moved to the locking position. The valve stem seal 1 can be easily attached.

  A slight gap 45 is provided between the high protrusion 24 of the engaging portion 22 and the reduced diameter portion 41 of the valve stem guide 40. As a result, no compressive stress is generated in the high protrusion 24 and elastic deformation is not caused. Therefore, the high protrusion 24 is maintained in a shape that is substantially the same as that before the attachment to the valve stem guide 40. The Therefore, the stepped portion 25 can be reliably locked by the stepped portion 43 of the valve stem guide 40.

  As described above, according to the present embodiment, the engaging portion 22 of the seal portion 20 that engages with the valve stem guide 40 protrudes from the low protruding portion 23 having the low back surface 23a and protrudes higher than the low protruding portion. It has a back surface 24 a and has a high protrusion 24 provided on the port side of the low protrusion 23 and a stepped portion 25 provided between the low protrusion 23 and the high protrusion 24. As a result, when the valve stem guide 40 is mounted, the low protrusion 23 which is a fitting portion with the valve stem guide 40 can be elastically deformed appropriately, and the low protrusion can be subjected to the valve with an appropriate deformation stress. The stem guide 40 is compression-fitted. As a result, it is possible to prevent the generation of excessive stress at the low protrusion 23 and to prevent an abnormal mounting state. Further, by providing the stepped portion 25 between the low protruding portion 23 and the high protruding portion 24, the stepped portion 25 is reliably locked to the valve stem guide 40. Therefore, the valve stem seal 1 can be easily attached to the valve stem guide 40 without excessively increasing the fitting force, the valve stem seal 1 is loosened, and the valve stem seal 1 is detached from the valve stem guide 40. Can be prevented. Further, even when external vibration or the like is applied after the mounting, the valve stem seal 1 can be prevented from loosening or dropping for a long time.

  Further, since the low back surface 23 a is provided substantially parallel to the axial direction of the valve stem guide 40, the low back surface 23 a of the low protrusion 23 and the diameter-expanded portion 42 of the valve stem guide 40 when mounted on the valve stem guide 40. The pressure contact area with the outer peripheral surface 42a of the low protrusion 23 is increased, and the variation in the in-plane direction of the compressive stress generated on the low back surface 23a of the low protrusion 23 can be suppressed.

  In particular, valve stem seals are used for engine valves in internal combustion engines of automobiles and general industrial equipment. However, since the engine valve to be used repeats sliding motion, the fitting force of the valve stem seal is reduced, and the valve stem seal may fall off. Under such a use environment, the above effect can be achieved by attaching the valve stem seal 1 of the present invention to the engine valve of the internal combustion engine.

  The valve stem seal according to the above embodiment has been described above, but the present invention is not limited to the described embodiment, and various modifications and changes can be made based on the technical idea of the present invention.

  For example, in the above embodiment, the surface 25a of the stepped portion 25 is an inclined surface that connects the low back surface 23a and the high back surface 24a, but is not limited thereto, and may be a surface perpendicular to the low back surface 23a. Good.

  Moreover, on the assumption that the low back surface 23a has an area where the necessary fitting force can be exhibited, the low back surface 23a and the high back surface 24a may have different areas or the same area. May be.

  Furthermore, in the above embodiment, the gap 45 is provided between the high protrusion 24 of the engagement portion 22 and the reduced diameter portion 41 of the valve stem guide 40, but this is not limiting, and the engagement portion 22 is not limited thereto. The high protrusion 24 and the reduced diameter portion 41 of the valve stem guide 40 may be in contact with each other.

  Furthermore, in the said embodiment, although the valve stem seal 1 is provided with the back pressure lip 26, it does not need to be equipped with this back pressure lip.

  Moreover, in this embodiment, although the cylindrical part 11 and the flange part 12 are directly connected with each other, not only this but the cylindrical part 11 and the flange part 12 may be connected via a curved part, Moreover, you may connect via the site | part of another shape.

  The valve stem seal of the present invention is suitably used for engine valves of various internal combustion engines, and is particularly useful as a valve stem seal for internal combustion engines of automobiles and general industrial equipment.

DESCRIPTION OF SYMBOLS 1 Valve stem seal 10 Holding part 11 Cylindrical part 11a Inner peripheral surface 12 Flange part 20 Seal part 21 Seal lip 21a Main seal lip 21b Sub seal lip 22 Engagement part 23 Low protrusion part 23a Low back surface 24 High protrusion part 24a High back surface 25 Stepped portion 25a Surface 26 Back lip 30 Garter spring 40 Valve stem guide 41 Reduced diameter portion 41a Outer peripheral surface 42 Expanded portion 42a Outer peripheral surface 43 Stepped portion 43a Flat surface 44 Corner corner 45 Clearance 50 Valve stem 50a Outer peripheral surface

Claims (6)

A valve stem seal that is attached to the valve stem and includes a substantially cylindrical holding portion formed of a metal material, and a seal portion that is connected to the holding portion and formed of an elastomer,
The holding part has a cylindrical part arranged around the outer peripheral surface of the valve stem guide, and a flange part provided at the upper end of the cylindrical part,
The seal portion is in contact with the outer peripheral surface of the valve stem, and is formed integrally with the seal lip and covers the inner peripheral surface of the cylindrical portion, and the outer peripheral surface of the valve stem guide An engaging portion that engages,
The engaging portion protrudes radially inward and has a low back surface, and further protrudes radially inward from the low protrusion and has a high back surface, and is provided closer to the port than the low protrusion portion. A valve stem seal comprising: a high protruding portion; and a stepped portion provided between the low protruding portion and the high protruding portion.   The valve stem seal according to claim 1, wherein the low back surface is provided substantially parallel to an outer peripheral surface of the valve stem guide.   The valve stem seal according to claim 1, wherein the stepped portion has an inclined surface that connects the low back surface and the high back surface. The valve stem guide is provided between a reduced diameter part protruding outward in the radial direction, an enlarged diameter part protruding further outward in the radial direction from the reduced diameter part, and the reduced diameter part and the enlarged diameter part. Have other stepped parts,
The low protrusion portion of the engagement portion is compression-fitted to the enlarged diameter portion of the valve stem guide, and the stepped portion of the engagement portion is locked to the other stepped portion of the valve stem guide. The valve stem seal according to claim 1, wherein:   2. The valve stem seal according to claim 1, wherein the seal portion has a back pressure lip formed at one end of the seal lip and slidably abutting on an outer peripheral surface of the valve stem.   The valve stem seal according to claim 1, wherein the valve stem seal is used for an engine valve of an internal combustion engine.