JPH0653704U - Seal for valve stem - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a seal for a valve stem that can efficiently lubricate the sliding surface between the valve stem and the guide without wasting lubricating oil, and does not require high design accuracy and processing accuracy. [Structure] A cylindrical guide 5 is attached to a cylinder head 1 having a lubricating liquid chamber 2, one end side of the guide 5 is exposed to the lubricating liquid chamber 2, and a valve stem 6 is reciprocally movable in a hole 4 of the guide 5. A resin seal ring having a swell 12 that is housed in the hole 4 on the other end side of the guide 5 and that holds the lubricating oil supplied to the gap B between the guide 5 and the valve stem 6 in the gap B. 10 is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a valve stem seal attached to a valve stem portion of an intake / exhaust mechanism of an engine of an automobile or a general industrial machine, for example.

[0002]

[Prior art]

 FIG. 2A is a cross-sectional view of the main parts of the intake / exhaust mechanism of the engine. A cylinder head 100 as a housing is provided with a lubricating liquid chamber 101 and a port 102, and a guide 104 as a guide cylinder is attached to a hole 103 penetrating from the lubricating liquid chamber 101 to the port 102 side. .

A valve stem 105 is reciprocally inserted in the guide 104. A valve cap 106 that opens and closes the port 102 is provided on one end side of the valve system 105, and a retainer 107 is attached to the other end side, that is, the lubricating liquid chamber 101 side. A spring 108 is interposed between the retainer 107 and the housing 100.

Further, an oil seal 109 as a seal ring is attached to the upper end side of the guide 104, that is, the lubricating liquid chamber 101 side. As shown in FIG. 2B, the oil seal 109 has a metal ring 110 and a seal body 111 made of a rubber-like elastic body. The seal body 111 has a seal lip 112.

Reference numeral 113 is a swinging arm, and 114 is a cam.

In the above structure, the swing arm 113 swings as the cam 114 rotates, and the valve stem 105 reciprocates in the guide 104. As a result, the port 102 and the combustion chamber 115 are opened and closed by the valve shade 106, and hot gas is sucked and exhausted.

On the other hand, the seal lip 112 of the oil seal 109 has a predetermined tightening margin with respect to the valve stem 105, and the seal lip 112 allows the lubricating oil in the lubricating liquid chamber 101 to move toward the inner peripheral surface of the guide 104 and the valve. The amount that leaks into the gap A with the stem 105 is controlled.

In this way, the oil seal 109 has both the function of supplying the lubricating oil to the clearance A to prevent the seizure between the guide 104 and the valve stem 105, and the function of controlling the supply amount of the lubricating oil. ing.

[0009]

[Problems to be solved by the device]

 However, in the above-mentioned conventional example, the lubricating oil is transmitted from the gap A through the hole 103 to the port 102 side and wastes the lubricating oil. On the other hand, in order to prevent this waste, the supply amount of the lubricating oil is reduced. If it is reduced, friction will cause wear and seizure.

As a measure against the above problem, it is conceivable to use an oil seal having a tightening margin aiming at an intermediate point between “leak” and “stop”, but the oil seal 109 should be adjusted so that an appropriate leak amount is obtained for each engine. Is required to be designed and processed with high accuracy, which increases the manufacturing cost and is not practical.

The present invention is intended to solve the above-mentioned problems, and it is possible to efficiently lubricate the sliding surface between the guide cylinder and the valve stem without wasting the lubricating liquid, and a valve that does not require high design and processing accuracy. It is intended to provide a seal for the stem.

[0012]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention mounts a guide cylinder on a housing having a lubricating liquid chamber so that one end side of the guide cylinder faces the lubricating liquid chamber and a valve stem is provided in the inner cylinder. A seal ring, which is reciprocally accommodated, is provided at the other end of the guide cylinder, the holding ring having a holding portion for holding the lubricating liquid supplied to the clearance between the inner peripheral surface of the guide cylinder and the valve stem in the clearance. .

[0013]

[Action]

 Since the seal ring is provided on the other end side of the guide cylinder, it does not hinder the supply of the lubricating liquid supplied from one end side of the guide cylinder, and the lubricating liquid is smoothly supplied to the gap. The lubricating oil supplied to the gap is held in the gap by the holding portion of the seal ring.

[0014]

【Example】

 FIG. 1A is a cross-sectional view of a main part of an intake / exhaust mechanism of an engine. A cylinder head 1 as a housing is provided with a lubricating liquid chamber 2 and a port 3, and a guide 5 as a guide cylinder is attached to a hole 4 penetrating from the lubricating liquid chamber 4 to the port 3 side. One end side, that is, the upper end side of the guide 5 is located inside the lubricating liquid chamber 2, and the other end side, that is, the lower end side faces the port 3.

A valve stem 6 is reciprocally inserted in the guide 5. A valve shade 7 for opening and closing the port 3 is provided on one end side of the valve stem 6, and a retainer 8 is attached to the other end side, that is, the lubricating liquid chamber 2 side. A spring 9 is interposed between the retainer 8 and the housing 1.

On the other hand, a resin seal ring 10 as shown in FIG. 1B is mounted on the lower end side of the guide 5 at a position facing the port 3, that is, in the hole 4. That is, the inner peripheral surface of the hole 4 has a wavy cross section and a saw shape, and the groove 11 is formed. The outer peripheral surface of the seal ring 10 is provided with an annular projection 17 that engages with the groove 11.

On the inner peripheral surface of the seal ring 10, there is provided a holding portion, that is, an annular undulation 12 having a wavy cross-sectional shape that is inclined toward the upper end side of the guide 5.

In this seal ring 10, the guide 5 is placed in the mold in advance and the middle mold is inserted into the hole 4, and then the resin molding material is injected between the middle mold and the guide 5 to integrally mold the mold. It was done. Since the area of the groove 11 is different from the other area in the radial direction, the amount of the molding material being compressed is different.

As a result, when the middle mold is pulled out, a difference occurs in the amount of restoration in the radial direction of the molding material, and the waviness 12 is molded. The size of the waviness 12 is as small as 0.05 mm or less. The seal ring 10 is made of a material having excellent heat resistance such as ethylene tetrafluoride resin.

Further, a swing arm 13, a cam 14, a push rod 15 and the like are provided on the lubricating liquid chamber 2 side.

In the above structure, the swing arm 13 swings as the cam 14 rotates, and the valve stem 6 reciprocates in the hole 4 of the guide 5. As a result, the space between the port 3 and the combustion chamber 16 is opened and closed by the valve shade 7, and hot gas is sucked and exhausted.

Since the seal ring 10 is located on the lower end side of the guide 5, it prevents the lubricating oil in the lubricating liquid chamber 2 from being supplied to the hole 4, that is, the gap B between the guide 5 and the valve stem 6. Supply smoothly without sacrificing.

Therefore, the friction between the guide 5 and the valve stem 6 can be reduced, the abrasion and the seizure thereof can be prevented, and the operating energy loss to the valve stem 6 can be reduced.

On the other hand, the waviness 12 of the seal ring 10 is inclined toward the upper end side of the guide 5 and is in contact with the valve stem 6 at a predetermined tightening allowance. Basically, it functions as a dead seal and does not require the function of leaking lubricating oil.

Therefore, the lubricating oil supplied to the gap B can be retained, the lubricating oil does not leak to the port 3 side, and the waste thereof can be prevented.

Further, basically, it is sufficient to exert only the dead-sealing function, so that the design accuracy and processing accuracy required for the inner diameter of the seal ring 10 can be relaxed as compared with the conventional one, and the manufacturing cost can be suppressed.

Furthermore, since the seal ring 10 is made of a resin having excellent heat resistance, it has good durability even when the temperature inside the port 3 is high, and has a longer life than a rubber-like elastic seal. .

[0028]

[Effect of device]

 As described above, since the seal ring is provided on the other end side of the guide cylinder, the supply of the lubricant liquid supplied from the one end side of the guide cylinder is not hindered and the lubricant liquid is smoothly supplied to the gap.

Therefore, the friction between the guide cylinder and the valve stem can be reduced by the efficient lubrication function, and the abrasion and the seizure can be prevented.

On the other hand, since the holding portion of the seal ring holds the lubricating oil supplied to the gap, it is possible to prevent the lubricating oil from being wasted.

Further, since the seal ring has only the function of retaining the lubricating liquid and does not need the function of leaking the lubricating liquid, the required design accuracy and processing accuracy can be relaxed as compared with the conventional one, and the manufacturing cost can be suppressed.

[Brief description of drawings]

1A is a sectional view of a valve stem mechanism of an engine to which the present invention is applied, FIG. 1B is an enlarged sectional view of an essential part of FIG.
(C) is an enlarged cross-sectional view of a main part of (B).

FIG. 2A is a sectional view of a conventional valve stem mechanism of an engine, and FIG. 2B is an enlarged sectional view of a main part of FIG.

[Explanation of symbols]

 1 Cylinder Head (Housing) 2 Lubricating Liquid Chamber 3 Port 4 Hole 5 Guide (Guide Tube) 6 Valve Stem 7 Valve Shaft 8 Retainer 9 Spring 10 Seal Ring 11 Groove 12 Waviness (Holding Part) 13 Shaking Arm 14 Cam 15 Push Depth 16 Combustion chamber 17 Protrusion B Gap

Claims (1)

[Scope of utility model registration request] 1. A guide cylinder is attached to a housing having a lubricating liquid chamber so that one end side of the guide cylinder faces the lubricating liquid chamber and a valve stem is reciprocally housed in the guide cylinder to provide the guide. For a valve stem characterized in that a seal ring having a holding portion for holding the lubricating liquid supplied to the gap between the inner peripheral surface of the guide cylinder and the valve stem in the gap is provided on the other end side of the pipe. sticker.