JP2018071567A - Valve stem seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve fixing force of a valve steam seal with respect to a valve guide.SOLUTION: A valve stem seal includes cylindrical fitting portions 11 and 12 brought into close contact with an outer peripheral surface of a valve guide 4, a seal lip 13 extending from the cylindrical fitting portion 11 and slidably brought into close contact with an outer peripheral surface of a valve stem 3 inserted into the valve guide 4, a reinforcement cylindrical body 15 integrally joined with outer peripheries of the cylindrical fitting portions 11 and 12, and a fitted ring 17 which can be fitted to an annular recession 41 formed on the outer peripheral surface of the valve guide 4 and is made of a material having rigidity higher than the cylindrical fitting portions 11 and 12. The fitted ring 17 is attached to an inner periphery of the reinforcement cylindrical body 15 in a state of being held by the cylindrical fitting portions 11 and 12 from axial direction both sides.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a valve stem seal that seals between, for example, a valve stem of a valve device of an automobile engine and a valve guide that supports the valve stem so as to be axially movable.

  In an intake / exhaust valve of an automobile engine, the valve stem is used to adjust the amount of engine oil supplied to a sliding surface between a valve stem and a valve guide that supports the axial movement of the valve stem and to seal exhaust gas. A seal is used.

  FIG. 8 shows an exhaust valve device for an engine. In FIG. 8, reference numeral 110 is a cylinder head of the engine, 111 is an exhaust port formed in the cylinder head 110, 112 is a valve for opening and closing the exhaust port 111, 113 is a valve stem extending from the valve 112, 114 is a valve guide that supports the valve stem 113 so as to be axially movable, 115 is a coil spring that urges the valve 112 in the valve closing direction via the valve stem 113, and 116 is a valve The cam 113 pushes down the stem 113 in the valve opening direction of the valve 112 against the urging force of the coil spring 115 every rotation.

  The valve stem seal 100 is attached to the upper end portion of the valve guide 114, and as shown in FIG. 9, a cylindrical fitting portion 101 made of a rubber elastic body that is tightly fitted to the outer peripheral surface of the upper end portion of the valve guide 114. A seal lip 102 and a back pressure lip 103 which are provided at the upper end thereof and are slidably brought into close contact with the outer peripheral surface of the valve stem 113, and a reinforcing cylinder 104 integrally joined to the cylindrical fitting portion 101. The engine oil flows from the oil chamber above the valve guide 114 to the sliding portion between the outer peripheral surface of the valve stem 113 and the inner peripheral surface of the valve guide 114 to maintain an appropriate lubricating state. It restricts excessive inflow.

  Further, the valve stem seal 100 is formed by fitting a fitting projection 101a formed on the inner peripheral surface of the cylindrical fitting portion 101 into an annular groove 114a formed on the outer peripheral surface of the valve guide 114. The guide 114 is prevented from coming off (see, for example, the following prior art document).

JP 2003-343733 A

  Here, in the space defined by the valve stem seal 100 on the upper side of the valve guide 114, exhaust gas pressure is generated from the exhaust port 111 shown in FIG. 8 to the outer peripheral surface of the valve stem 113 and the inner peripheral surface of the valve guide 114. Since the back pressure P also increases as the engine output increases in recent years, the valve stem seal 100 against the valve guide 114 increases. There is a need to improve the fixing force and reliably prevent it from coming off.

  The present invention has been made in view of the above points, and its technical problem is to improve the fixing force of the valve stem seal to the valve guide.

  In order to solve the technical problem described above, a valve stem seal according to the invention of claim 1 includes a cylindrical fitting portion that is in close contact with the outer peripheral surface of the valve guide and an end portion of the cylindrical fitting portion. A seal lip slidably in contact with an outer peripheral surface of a valve stem inserted through the valve guide, a reinforcing cylinder integrally joined to an outer periphery of the cylindrical fitting portion, and an outer periphery of the valve guide A ring that can be locked to an annular recess formed on the surface and made of a material that is higher in rigidity than the cylindrical fitting part, and the ring to be locked is an inner periphery of the reinforcing cylinder. And attached in a state of being sandwiched by the cylindrical fitting portion from both axial sides.

  The valve stem seal according to a second aspect of the present invention is the valve stem seal according to the first aspect, wherein the reinforcing cylindrical body is formed with an annular step portion so as to have a large diameter on the side opposite to the seal lip in the axial direction. It consists of a cylinder body and a sub cylinder that is press-fitted to the large diameter side of the annular step portion, and the outer diameter portion of the locked ring is sandwiched between the annular step portion and the sub cylinder. It is characterized by that.

  The valve stem seal according to a third aspect of the present invention is the valve stem seal according to the first aspect, wherein the locked ring is integrally joined with the cylindrical fitting portion, and the cylindrical shape on both axial sides of the locked ring. The fitting portions are continuous with each other through notches formed in the locked ring.

  According to the valve stem seal of the present invention, the locked ring made of a material having rigidity higher than that of the cylindrical fitting portion is sandwiched by the cylindrical fitting portion from both sides in the axial direction on the inner periphery of the reinforcing cylindrical body. Since the locked ring is locked in an annular recess formed in the outer peripheral surface of the valve guide, the fixing force of the valve stem seal with respect to the valve guide can be improved.

1 is a half sectional view showing a first embodiment of a valve stem seal according to the present invention by cutting along a plane passing through an axis O. FIG. 1 is a half cross-sectional view of a mounting state in which a first embodiment of a valve stem seal according to the present invention is cut along a plane passing through an axis O. FIG. 1 is a half sectional view of a separated state before assembly showing a first embodiment of a valve stem seal according to the present invention by cutting along a plane passing through an axis O. FIG. FIG. 5 is a half sectional view showing a second embodiment of a valve stem seal according to the present invention by cutting along a plane passing through an axis O; FIG. 5 is a half cross-sectional view showing a second embodiment of the valve stem seal according to the present invention cut at a position different from the cross section of FIG. FIG. 6 is a half cross-sectional view showing a second embodiment of the valve stem seal according to the present invention cut along a plane perpendicular to the axis at the A-A ′ position in FIGS. 4 and 5. FIG. 5 is a half cross-sectional view of a mounting state in which a second embodiment of the valve stem seal according to the present invention is cut and shown at the same position as the cross section of FIG. It is sectional drawing which shows the valve | bulb of an engine with a valve stem seal. FIG. 6 is a half cross-sectional view of a mounting state in which an example of a conventional valve stem seal is shown cut by a plane passing through an axis O.

  Hereinafter, a preferred embodiment of a valve stem seal according to the present invention will be described with reference to the drawings. First, FIG. 1 shows a first embodiment.

  That is, the valve stem seal 1 according to the first embodiment is continuous with the cylindrical fitting portions 11 and 12 made of rubber elastic bodies arranged side by side in the vertical direction (axial direction) and the upper cylindrical fitting portion 11. The sealing lip 13 and the back pressure lip 14 made of rubber elastic body, the reinforcing cylinder 15 made of metal that reinforces the cylindrical fitting portions 11 and 12 from the outer peripheral side, and the inner periphery of the reinforcing cylinder 15 are attached. A locked ring 17 made of a material having higher rigidity and moderate elasticity than the cylindrical fitting portions 11 and 12 and a garter spring 18 attached to the outer periphery of the seal lip 13 are provided.

  The reinforcing cylinder 15 includes a reinforcing cylinder body 151 and a sub cylinder 152. Among these, the reinforcing cylinder body 151 includes a relatively small-diameter upper cylindrical portion 151a, a lower-side relatively large-diameter lower cylindrical portion 151b, and an upper cylindrical portion 151a and a lower cylindrical portion 151b. It has an annular stepped portion 151c and an inward flange portion 151d extending from the upper end of the upper cylindrical portion 151a to the inner diameter side. The sub-cylinder 152 has a simple cylindrical shape, and is a lower cylinder in the reinforcing cylindrical body 151. The portion 151b is fitted to the inner peripheral surface with an appropriate fastening margin.

  As shown in FIG. 2, the cylindrical fitting portions 11 and 12 are, for example, mounted in close contact with an appropriate crushing margin on the outer peripheral surface of a cylindrical valve guide 4 in an engine valve device. Of the cylindrical fitting portions 11 and 12, the upper cylindrical fitting portion 11 is vulcanized and bonded to the inner peripheral surface of the upper cylindrical portion 151 a of the reinforcing cylindrical body 151 in the reinforcing cylindrical body 15. The cylindrical fitting portion 12 is vulcanized and bonded to the inner peripheral surface of the sub-cylindrical body 152 in the reinforcing cylindrical body 15, and the cylindrical fitting portions 11 and 12 are cylindrical surfaces whose inner peripheral surfaces have the same diameter. It is formed in a shape.

  A radial portion 11a extending from the upper end of the tubular fitting portion 11 toward the inside in the radial direction is vulcanized and bonded to the inner side surface (lower surface) of the inward flange portion 151d of the reinforcing cylindrical body 151. 13 and the back pressure lip 14 are provided so as to branch from the inner diameter end of the radial portion 11a to both sides in the axial direction.

  Of these, the base of the seal lip 13 is joined in the vicinity of the inner diameter end of the inward flange portion 151d of the reinforcing cylinder body 151, and extends axially upward therefrom, and the inner peripheral surface in the vicinity of the upper end is shown in FIG. 2, the engine oil in an oil chamber (not shown) existing above the valve guide 4 is slidably brought into close contact with the outer peripheral surface of the valve stem 3 inserted through the valve guide 4. Inflow to the sliding portion between the outer peripheral surface of the valve stem 3 and the inner peripheral surface of the valve guide 4 is limited. In other words, by allowing an appropriate amount of engine oil to flow into the sliding portion between the valve stem 3 and the valve guide 4, lubrication of the sliding portion between the valve stem 3 and the valve guide 4 is maintained, and a valve (not shown) It is intended to suppress wear.

  The back pressure lip 14 extends in the shape of a conical cylinder so as to branch from the base of the seal lip 13 downward in the axial direction, and the inner peripheral surface near the lower end thereof can slide on the outer peripheral surface of the valve stem 3. By being in close contact, the pressure of the exhaust gas from the exhaust port (not shown) is blocked from being applied to the inner periphery of the seal lip 13 through a minute gap between the sliding portions of the valve stem 3 and the valve guide 4. To do.

  The locked ring 17 is configured to fix the valve stem seal 1 to the valve guide 4 in a retaining state by fitting an inner diameter portion into an annular recess 41 formed on the outer peripheral surface of the valve guide 4. Thus, it is made of a material having higher rigidity than the cylindrical fitting portions 11 and 12 and having appropriate elasticity, for example, a synthetic resin.

  The locked ring 17 is disposed on the inner periphery of the lower cylindrical portion 151 b of the reinforcing cylindrical body 151 in the reinforcing cylindrical body 15, and the outer diameter portion is an annular stepped portion of the reinforcing cylindrical main body 151 in the reinforcing cylindrical body 15. The cylindrical fitting is sandwiched between the axially opposite sides (up and down) between 151c and the upper end of the sub-cylinder 152 in the reinforcing cylinder 15, and the radial intermediate part is flush with the lower surface of the annular stepped part 151c. It is attached in a state of being sandwiched between the lower end portion of the joint portion 11 and the upper end portion of the cylindrical fitting portion 12 that is flush with the upper end portion of the sub-cylindrical body 152, and the inner diameter end portion is cylindrically fitted. The diameter is appropriately smaller than the inner diameter of the portions 11 and 12 and the outer diameter of the valve guide 4.

  The garter spring 18 is formed by connecting a long metal coil spring in an annular shape, and is fitted into an annular groove formed on the outer peripheral surface of the seal lip 13 so that the seal lip 13 is pressed against the outer peripheral surface of the valve stem 3. Compensates for force.

  The locked ring 17 is first inserted into the inner periphery of the lower cylindrical portion 151b of the reinforcing cylindrical body 151 from the state before assembly shown in FIG. 3, and is further inserted into the inner periphery of the lower cylindrical portion 151b. By press-fitting 152, it can be fixed to the state shown in FIG.

  Further, the locked ring 17 is provided with a cutting portion 17a at one place in the circumferential direction so as to be elastically deformable in the radial direction, thereby to the inner periphery of the lower cylindrical portion 151b in the reinforcing cylindrical body 151. Can be easily inserted. In addition, it is preferable to form a chamfer 17b at the inner diameter lower portion of the locked ring 17, and the cut portion 17a of the locked ring 17 is inclined with respect to the radial direction and the axial direction. Can do.

  On the other hand, an annular recess 41 is formed on the outer peripheral surface of the valve guide 4 shown in FIG. 2, and the inner diameter portion of the locked ring 17 in the valve stem seal 1 can be fitted into the annular recess 41. As a result, the valve stem seal 1 is locked with respect to the direction of withdrawal from the valve guide 4 (upward direction). The upper outer peripheral surface 42 on the upper side of the annular recess 41 and the lower outer peripheral surface 43 on the lower side of the annular recess 41 have the same diameter, and a chamfer 44 is formed on the upper end portion of the upper outer peripheral surface 42.

  In order to attach the valve stem seal 1 having the above configuration to the valve guide 4, the lower end portion of the reinforcing cylinder body 15, that is, the lower end portions of the reinforcing cylinder body 151 and the auxiliary cylinder body 152 starts from the upper side of the valve guide 4. In the process, first, the lower cylindrical fitting portion 12 rides on the chamfer 44 of the valve guide 4 and is compressed to the outer diameter side while being compressed to the outer diameter side through the upper outer peripheral surface 42 side. Next, the locked ring 17 climbs onto the chamfer 44 and moves to the upper outer peripheral surface 42 of the valve guide 4 while being compressed to the outer diameter side, and further, the upper cylindrical fitting portion 11 rides on the chamfer 44 and is externally inserted into the upper outer peripheral surface 42 of the valve guide 4 while being compressed to the outer diameter side. Further, the chamfer 17 b formed on the inner diameter portion of the locked ring 17 can further reduce the resistance when extrapolated to the valve guide 4.

  When the locked ring 17 reaches the outer periphery of the annular recess 41 of the valve guide 4, the locked ring 17 has an inner diameter portion of the annular recess 41 of the valve guide 4 due to a restoring force toward the inner diameter side against compression. Fits in and completes installation. Therefore, the valve stem seal 1 can be easily mounted only by extrapolating from above the valve guide 4.

  Further, in the space defined between the upper end portion of the valve guide 4 and the back pressure lip 14 of the valve stem seal 1, the pressure of exhaust gas from a port (not shown) below the valve guide 4 is Is introduced through a small gap in the sliding portion between the outer peripheral surface of the valve guide 4 and the inner peripheral surface of the valve guide 4, and this pressure is applied to the back pressure lip 14 of the valve stem seal 1 and the inward flange portion 151 d ( By acting as a back pressure P on the radial direction portion 11 a), a load is applied to the valve stem seal 1 in the withdrawal direction (upward), but the upward movement of the valve stem seal 1 is caused by the movement of the locked ring 17. The inner diameter portion is regulated by being fitted into the annular recess 41. In addition, the locked ring 17 is higher in rigidity than the cylindrical fitting portions 11 and 12 made of a rubber elastic body, and between the annular stepped portion 151c of the reinforcing cylindrical body 151 and the sub cylindrical body 152, and the cylindrical fitting. Since it is fixed in a state of being sandwiched between the joint portions 11 and 12 from both sides (upper and lower) in the axial direction, even if it receives a load in the pull-out direction, it does not easily come off from the annular recess 41 or be damaged. Therefore, the fixing force of the valve stem seal 1 can be remarkably improved.

  Next, FIGS. 4 to 7 show a second embodiment of the valve stem seal according to the present invention. In this embodiment, the difference from the first embodiment is a reinforcing cylinder. Reference numeral 15 denotes a single member having a cylindrical portion 15a and an inward flange portion 15b bent from the upper end to the inner diameter side. The cylindrical portion 15a is a simple cylindrical shape having no annular stepped portion, and is engaged. The retaining ring 17 is disposed on the inner periphery in the axial direction of the cylindrical portion 15a of the reinforcing cylindrical body 15, and the outer diameter portion is integrally joined to the cylindrical fitting portion 16 made of a rubber elastic body. In the point.

  Specifically, the cylindrical fitting portion 16 is vulcanized and bonded to the inner peripheral surface of the cylindrical portion 15a of the reinforcing cylindrical body 15, and the upper cylindrical fitting portion 161 located above the locked ring 17; It consists of a lower cylindrical fitting portion 162 located below the locked ring 17, extends from the upper end of the upper cylindrical fitting portion 161 inward in the radial direction, and has an inward flange portion 15 b of the reinforcing cylindrical body 15. The seal lip 13 and the back pressure lip 14 are provided so as to branch off to both sides in the axial direction from the inner diameter end of the radial portion 16a that is vulcanized and bonded to the inner side surface (lower surface). The configurations of the seal lip 13, the back pressure lip 14, and the garter spring 18 are the same as those in the first embodiment.

  As shown in FIGS. 4 to 6, the locked ring 17 has a plurality of cutout grooves 17c having a shape that is hollowed out from the inner diameter portion toward the outer diameter side. The diameter end (groove bottom) is on the outer diameter side of the inner peripheral surface of the cylindrical fitting portion 16 (the upper cylindrical fitting portion 161 and the lower cylindrical fitting portion 162). The upper cylindrical fitting portion 161 and the lower cylindrical fitting portion 162 are continuous with each other via a continuous portion 163 made of a rubber elastic body formed so as to cover the bottom of the notch groove 17c.

  That is, when the cylindrical fitting portion 16 and the seal lip 13 and the back pressure lip 14 that are continuous with the cylindrical fitting portion 16 are integrally formed with the reinforcing cylinder 15, the cylindrical fitting portion 16 is previously locked to the inner periphery of the cylindrical portion 15 a of the reinforcing cylinder 15. The ring 17 is positioned and fixed, and the molding rubber material is filled in a cavity defined between the reinforcing cylinder 15 and the locked ring 17 and the inner surface of the mold (not shown). Is formed on both sides in the axial direction of the locked ring 17 through the notch grooves 17c, so that the cylindrical fitting portion 16 has an upper cylindrical fitting portion 161 and a lower cylindrical fitting portion as shown in the figure. 162 are continuous with each other through the continuous portion 163 and are formed into a shape that holds the locked ring 17 from both sides in the axial direction.

  Similarly to the first embodiment, the locked ring 17 can be elastically deformed in the radial direction by providing a cutting portion 17a at one place in the circumferential direction, and can be chamfered at the lower portion of the inner diameter 17b. It is also preferable to form

  To attach the valve stem seal 1 having the above configuration to the valve guide 4 as shown in FIG. 7, the valve stem seal 1 is extrapolated from above the valve guide 4 with the lower end portion of the reinforcing cylinder 15 at the top. First, the lower cylindrical fitting portion 162 rides on the chamfer 44 of the valve guide 4 and is externally inserted to the lower outer peripheral surface 43 side via the upper outer peripheral surface 42 while being compressed to the outer diameter side. The locked ring 17 rides on the chamfer 44 and moves to the upper outer peripheral surface 42 of the valve guide 4 while being compressed to the outer diameter side, and further, the upper cylindrical fitting portion 161 rides on the chamfer 44. While being compressed to the outer diameter side, the valve guide 4 is inserted into the upper outer peripheral surface 42.

  When the locked ring 17 reaches the outer periphery of the annular recess 41 of the valve guide 4, the locked ring 17 has an inner diameter portion of the annular recess 41 of the valve guide 4 due to a restoring force toward the inner diameter side against compression. Fits in and completes installation. Therefore, the valve stem seal 1 can be easily mounted just by extrapolating from above the valve guide 4 as in the first embodiment.

  Further, in the space defined between the upper end portion of the valve guide 4 and the back pressure lip 14 of the valve stem seal 1, the pressure of exhaust gas from a port (not shown) below the valve guide 4 is This pressure is introduced through a small gap in the sliding portion between the outer peripheral surface of the valve guide 4 and the inner peripheral surface of the valve guide 4, and this pressure is applied to the back pressure lip 14 of the valve stem seal 1 and the inward flange portion 15 b (diameter of the reinforcing cylinder 15. By acting as a back pressure P on the directional part 11a), a load is applied to the valve stem seal 1 in the withdrawal direction (upward), but the upward movement of the valve stem seal 1 is caused by the inner diameter of the locked ring 17. The portion is regulated by being fitted into the annular recess 41. Moreover, the locked ring 17 has higher rigidity than the cylindrical fitting portion 16 made of a rubber elastic body, and the cylindrical fitting portion 16 (the upper cylindrical fitting portion 161 and the lower cylindrical fitting portion 162). Since it is integrated in a state of being sandwiched from both sides in the axial direction, it does not easily come off or be damaged from the annular recess 41 even when a load in the pull-out direction is applied, and therefore the fixing force of the valve stem seal 1 Can be remarkably improved.

  The cutout groove 17c of the locked ring 17 may have a shape hollowed from the outer diameter portion toward the inner diameter side, that is, even in this way, the upper cylindrical fitting portion 161 and the lower cylindrical fitting portion. When molding 162, the molding rubber material can be shaped on both sides in the axial direction of the ring 17 to be locked through the notch groove 17c.

DESCRIPTION OF SYMBOLS 1 Valve stem seals 11 and 12 Cylindrical fitting part 13 Seal lip 14 Back pressure lip 15 Reinforcement cylinder 15a Cylindrical part 151 Reinforcement cylinder body 151a Upper cylinder part 151b Lower cylinder part 151c Annular level difference part 152 Sub cylinder 16 Cylinder Shape fitting portion 161 upper cylindrical fitting portion 162 lower cylindrical fitting portion 163 continuous portion 17 locked ring 17c notch groove 18 garter spring 3 valve stem 4 valve guide 41 annular recess

Claims (3)

  A cylindrical fitting portion that is in close contact with the outer peripheral surface of the valve guide, and extends from an end of the cylindrical fitting portion, and is slidably in close contact with the outer peripheral surface of the valve stem that is inserted through the valve guide. A seal lip, a reinforcing cylinder integrally joined to the outer periphery of the cylindrical fitting portion, and an annular recess formed on the outer peripheral surface of the valve guide can be locked to the cylindrical fitting portion. And a locked ring made of a material having high rigidity, and the locked ring is attached to the inner periphery of the reinforcing cylindrical body while being sandwiched by the cylindrical fitting portion from both axial sides. Valve stem seal characterized by   From the reinforcing cylinder body in which the annular step portion is formed so that the reinforcing cylinder has a large diameter on the side opposite to the seal lip in the axial direction, and the sub cylinder that is press-fitted to the large diameter side of the annular step portion. The valve stem seal according to claim 1, wherein an outer diameter portion of the locked ring is sandwiched between the annular stepped portion and the sub-cylindrical body.   The locked ring is integrally joined with the cylindrical fitting portion, and the cylindrical fitting portions on both sides in the axial direction of the locked ring are continuous with each other via notches formed in the locked ring. The valve stem seal according to claim 1, wherein:

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