JP2006017027A - Engine valve lubricating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine valve lubricating device for forcibly lubricating a contact portion between a top surface of a valve stem and a lifter without complicating a lifter structure. <P>SOLUTION: The engine valve lubricating device comprises a guide hole 11 formed in a cylinder head 1 coaxially with the valve stem 5 and the lifter 20 of a bottomed cylindrical shape slidably installed in the guide hole 11 and reciprocates the valve stem 5 by rotation of a cam 8 through the intermediary of the lifter 20. A through hole24 for interconnecting a valve operating chamber 18 and a back chamber 17 is formed through the lifter 20 and an oil jet 30 is provided to extend from the through hole 24 toward a top part of the valve stem 5. The device is constructed to allow lubrication oil sucked from the valve operating chamber 19 into the back chamber 17 to blow out from the oil jet 30 toward the contact portion of the valve stem 5 and the lifter 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an improvement in an engine valve lubrication device for lubricating an abutment portion between a top surface of a valve stem and a lifter.

  In a direct acting valve mechanism that opens and closes a valve by reciprocating a lifter by rotation of a cam, the contact surface between the top surface of the valve stem and the lifter is surrounded by the lifter, and it is difficult to lubricate this.

  Conventionally, as this type of engine valve lubrication apparatus, there are those shown in FIGS. 3 and 4 (see Patent Document 2).

  This valve mechanism opens and closes the valve 109 by reciprocating the valve stem 102 via the lifter 105 by the rotation of the cam 108.

  A valve stem 102 is slidably supported on the cylinder head 101 via an oil seal 103, and a covered cylindrical lifter 105 is slidably supported.

  A retainer 104 is fixed to the upper portion of the valve stem 102, and a valve spring 107 is interposed between the retainer 104 and the cylinder head 101. The valve spring 107 biases the valve stem 102 toward the cam 108 side.

  The lifter 105 is provided so as to surround the outer periphery of the retainer 104, the inner center portion thereof is brought into contact with the top surface of the valve stem 102, and the movement of the lifter 105 that reciprocates following the cam 108 is transmitted to the valve stem 102. 109 is opened and closed.

  A disc-shaped shim 106 is interposed between the lifter 105 and the cam 108. The clearance between the lifter 105 and the cam 108 is adjusted by changing the thickness of the shim 106.

  In such a direct acting valve mechanism, it is necessary to lubricate the top surface of the valve stem 102 and the contact portion of the lifter 105 to suppress wear.

Therefore, conventionally, an oil passage 110 is formed through the center of the lifter 105, a horizontal communication passage 111 that communicates with the oil passage 110 between the upper surface of the lifter 105 and the shim 106, and a vertical passage that communicates with the horizontal communication passage 111. 112 is formed. During operation of the engine, lubricating oil is supplied to the top surface of the valve stem 102 through these passages 112, 111, 110.
Japanese Utility Model Publication No. 7-4806 Japanese Utility Model Publication No. 1-1119808

  However, in such a conventional valve lubrication device for an engine, since the passages 111 and 112 are formed between the upper surface of the lifter 105 and the shim 106, the processing of the lifter 105 becomes complicated. There was a problem of causing an increase in size.

  Further, since the oil passage 110 is opened at the center of the lifter 105, the contact area of the lifter 105 with respect to the valve stem 102 is reduced, and there is a problem that wear of the contact portion is accelerated.

  The present invention has been made in view of the above problems, and provides an engine valve lubrication device that forcibly lubricates the top surface of the valve stem and the contact portion of the lifter without complicating the structure of the lifter. The purpose is to do.

  In the present invention, the cylinder head is provided with a guide hole formed coaxially with the valve stem, and a bottomed cylindrical lifter that is slidably interposed in the guide hole and abuts the top of the valve stem. In an engine that opens and closes a valve by reciprocating the lifter by rotation, a through hole is formed through the lifter to communicate the valve chamber and the rear chamber of the lifter, and extends from the through hole toward the top of the valve stem. An oil jet is provided, and the lubricating oil sucked into the back chamber from the valve chamber through the through hole is ejected from the oil jet toward the contact portion between the valve stem and the lifter.

  According to the present invention, at the time of engine operation, a part of the lubricating oil supplied to the sliding contact portion between the cam and the lifter is sucked from the valve operating chamber to the back chamber through the through hole, and the contact portion between the valve jet and the lifter is discharged from the oil jet. Erupts towards

  Since the oil jet extends from the through hole toward the contact portion between the valve stem and the lifter, most of the lubricating oil ejected from the oil jet reaches the contact portion between the valve stem and the lifter, and wear of the sliding contact portion is reduced. It can be suppressed.

  Since the lifter has a structure in which a through-hole is formed and an oil jet connected to the through-hole is attached, the processing of the lifter is prevented from being complicated, and the lifter does not need to be enlarged.

  Embodiments of the present invention will be described with reference to the accompanying drawings.

  In FIG. 1, 1 is a cylinder head, 2 is an exhaust port, 3 is a valve that opens and closes the exhaust port 2, 8 is a cam, 16 is a piston, and 15 is a cylinder that slidably accommodates the piston 16.

  The valve 3 has a valve stem 5 extending in an axial shape, and the valve stem 5 is slidably supported on the cylinder head 1 via a valve guide 4. A retainer 6 is attached in the middle of the valve stem 5, and a valve spring 7 is interposed between the retainer 6 and the cylinder head 1. The valve spring 7 biases the valve stem 5 toward the cam 8 side.

  A guide hole 11 is formed in the cylinder head 1 coaxially with the valve stem 5, and a bottomed cylindrical lifter 20 is slidably interposed in the guide hole 11. The valve stem 5 is reciprocated through the lifter 20 by the rotation of the cam 8, and the exhaust port 2 is opened and closed by the valve 3.

  As shown in FIG. 2, the lifter 20 is formed in a bottomed cylindrical shape so as to surround the top of the valve stem 5, the retainer 6, and the like. The lifter 20 includes a cylindrical portion 21 slidably interposed in the guide hole 11 of the cylinder head 1, a disc portion 22 that connects the upper end portion of the cylindrical portion 21 against the cam 8, and the disc portion 22 It has a columnar convex portion 23 that protrudes from the center of the lower surface and abuts against the valve stem 5, and these are integrally formed.

  The lifter 20 is a shimless type that does not include a shim between the lifter 20 and the cam 8, and a plurality of protrusions 23 having different protrusion heights are prepared, from which the clearance between the lifter 20 and the cam 8 is increased. The appropriate one is selected and inserted.

  A back chamber 17 is defined between the lifter 20, the guide hole 11 of the cylinder head 1, and the lower deck 12. The rear chamber 17 communicates with a valve operating chamber 19 in which the cam 8 and the like are accommodated by an opening 18 on the lower deck 12. A valve spring 7 and the like are accommodated in the back chamber 17.

  As a gist of the present invention, a through hole 24 penetrating the lifter 20 is formed, an oil jet 30 extending from the through hole 24 toward the top of the valve stem 5 is provided, and the through hole is formed from the valve operating chamber 19. The lubricating oil sucked into the back chamber 17 through 24 is ejected from the oil jet 30 toward the contact portion between the valve stem 5 and the lifter 20.

  The through hole 24 is formed through the disc portion 22 of the lifter 20. The through hole 24 is formed avoiding the central portion of the disk portion 22 and is formed away from the convex portion 23.

  The oil jet 30 is formed by, for example, using a pipe material having an outer diameter of about 1 mm and bending the pipe material into an L shape.

  The oil jet 30 is attached so as to protrude from the lower surface side of the disk portion 22 of the lifter 20, and the tip portion 31 opens toward the top of the valve stem 5.

  The front end portion 31 of the oil jet 30 is throttled in front of the opening end so as to increase the speed of the lubricating oil to be ejected.

  Next, the operation will be described.

  During engine operation, the valve stem 5 is reciprocated through the lifter 20 by the rotation of the cam 8, and the exhaust port 2 is opened and closed by the valve 3. At this time, since the top of the valve stem 5 is slightly inclined with respect to the valve guide 4, the top surface of the valve stem 5 is in sliding contact with the end surface of the convex portion 23 of the lifter 20. For this reason, it is necessary to lubricate the contact portion of the top surface of the valve stem 5 and the lifter 20 to suppress wear.

  During engine operation, lubricating oil sent from the oil pump is supplied to the sliding contact portion between the cam 8 and the lifter 20, and the sliding contact portion is lubricated. A part of the lubricating oil supplied onto the lifter 20 is sucked from the valve operating chamber 19 to the back chamber 17 through the through hole 24 and is ejected from the oil jet 30 toward the contact portion between the valve stem 5 and the lifter 20. Thereby, the lubricating oil ejected from the oil jet 30 is supplied to the top surface of the valve stem 5 and the abutting portion of the lifter 20, and the sliding contact portion is lubricated to suppress wear and seizure.

  A back chamber 17 defined between the lifter 20 and the guide hole 11 of the cylinder head 1 and the lower deck 12 communicates with the valve operating chamber 19 through an opening 18 on the lower deck 12, but the lifter 20 reciprocates at high speed. As the valve moves, a pressure difference with the valve chamber 19 is generated, and a part of the lubricating oil is sucked from the valve chamber 19 through the through hole 24 to the back chamber 17, and from the oil jet 30 to the valve stem 5 and the lifter 20. It ejects toward the contact part, and this sliding contact part is forcibly lubricated.

  Since the oil jet 30 extends from the through hole 24 toward the contact portion between the valve stem 5 and the lifter 20 and the tip portion 31 of the oil jet 30 is throttled, most of the lubricating oil ejected from the oil jet 30 is the valve. The contact portion between the stem 5 and the lifter 20 is reached, and wear and seizure of the sliding contact portion are suppressed.

  On the other hand, when the oil jet 30 connected to the through hole 24 is not provided, it is difficult for the lubricating oil ejected from the through hole 24 to the back chamber 17 to reach the contact portion between the valve stem 5 and the lifter 20.

  Since the front end portion 31 of the oil jet 30 is squeezed in front of the opening end, the speed of the lubricating oil to be ejected from this is increased, and the lubricating oil reaches the contact portion between the valve stem 5 and the lifter 20, and this sliding contact portion Wear is suppressed.

  The lifter 20 has a cylindrical portion 21 that is in sliding contact with the guide hole 11 and a disk portion 22 that is in sliding contact with the cam 8, and the through-hole 24 is formed through the disk portion 22 of the lifter 20. The lubricating oil to be sucked into the through-holes 24 can be efficiently sucked, and the amount of lubricating oil guided to the oil jet 30 can be sufficiently secured.

  Since the lifter 20 has a structure in which the through hole 24 is opened and the oil jet 30 connected to the through hole 24 is attached, the processing of the lifter 20 is avoided from being complicated, and the lifter 20 is not enlarged. That's it.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  INDUSTRIAL APPLICABILITY The present invention can be used for an engine valve lubrication device that lubricates a contact surface between a top surface of a valve stem and a lifter.

1 is a cross-sectional view of an engine showing an embodiment of the present invention. Sectional drawing of lifters etc. similarly. Sectional drawing of the engine which shows a prior art example. Sectional drawing of lifters etc. similarly.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Exhaust port 3 Valve 5 Valve stem 8 Cam 17 Back chamber 19 Valve chamber 20 Lifter 24 Through-hole 30 Oil jet

Claims (3)

A guide hole formed coaxially with the valve stem in the cylinder head;
A bottomed cylindrical lifter that is slidably interposed in the guide hole and abuts the top of the valve stem,
In an engine that opens and closes a valve by reciprocating this lifter by rotation of a cam,
Forming a through hole that penetrates the lifter and communicates the valve operating chamber and the back chamber of the lifter,
An oil jet extending from the through hole toward the top of the valve stem is provided,
Lubricating oil sucked into the back chamber from the valve chamber through the through hole is jetted from the oil jet toward a contact portion between the valve stem and the lifter. Valve lubrication device. The lifter has a cylindrical portion that is in sliding contact with the guide hole and a disk portion that is in sliding contact with the cam.
2. The engine valve lubrication device according to claim 1, wherein the disk portion is penetrated through the through hole.   The valve lubricating device for an engine according to claim 1 or 2, wherein the oil jet is formed by constricting a tip portion thereof.

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