KR20180085934A - Tappet and engine including the same - Google Patents

Abstract

An engine tappet may include a tappet head and a tappet rod. The tappet head may be in contact with an engine cam. The tappet rod may extend from the tappet head and elevate while being rotated by the rotational force of the cam. A groove may be formed in the outer peripheral surface of the tappet rod. The groove in the outer peripheral surface of the tappet rod may reduce the weight of the tappet. Accordingly, a low rigidity can be given to the spring of a valve train and the friction of the valve train can be reduced. In addition, the groove reduces the contact area between the tappet rod and the tappet groove inside surface of a cylinder block, and thus friction can be reduced between the tappet rod and the inside surface of the tappet groove. As a result, the rotational motion of the tappet is improved and lubricity can be improved between the tappet and the cam.

Description

[0001] TAPPET AND ENGINE INCLUDING THE SAME [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tappet and an engine including the tappet. More particularly, the present invention relates to a tappet that converts a rotational force of a cam into a linear motion force and transmits the same to an intake and exhaust valve.

Generally, the power generated in the combustion chamber of the engine can be transmitted to the camshaft. The rotational force of the cam of the camshaft can be converted to the linear movement force by the tappet. The tappet is lifted and rotated to transmit the linear motion force to the valve train which is a valve opening / closing mechanism.

The valve train may include a valve spring. The valve spring resiliently supports the tappet toward the cam side via the push rod, and can absorb the kinetic energy and shock generated when the tappet travels back and forth. Thus, the valve spring affects the load transmitted to the cam through the tappet, which in turn affects the fuel economy of the engine and may also affect the wear of the tappet due to friction between the tappet and cam. Accordingly, it is necessary to develop a technique capable of reducing the wear of the tappet while reducing the stiffness of the valve spring.

The present invention provides a tappet that can reduce the valve spring rigidity of a valve train while reducing wear on the cam.

The present invention also provides an engine including the tappet described above.

The tappet of the engine according to one aspect of the present invention may include a tappet head and a tappet rod. The tappet head can contact the cam of the engine. The tappet rod extends from the tappet head and can be raised and lowered while being rotated by the rotational force of the cam. Grooves may be formed on the outer circumferential surface of the tappet rod.

In exemplary embodiments, the groove may be spiral.

In exemplary embodiments, the spiral groove may have a depth of 1 mm to 1.5 mm.

In exemplary embodiments, the helical groove may have a pitch of 5 mm to 7 mm.

In exemplary embodiments, the spiral groove may have a width of 1 mm to 1.5 mm.

In exemplary embodiments, the groove may be formed along an axial direction of the tappet rod.

An engine according to another aspect of the present invention may include a cam, a tappet, and a cylinder block. The cam can be rotated by the power generated in the combustion chamber. The tappet may include a tappet head and a tappet rod. The tappet head can contact the cam. The tappet rod extends from the tappet head and can be raised and lowered while being rotated by the rotational force of the cam. Grooves may be formed on the outer circumferential surface of the tappet rod. The cylinder block may have a tappet groove for receiving the tappet so as to be able to lift the tappet.

In exemplary embodiments, the groove may be spiral.

According to the present invention, the groove formed on the outer circumferential surface of the tappet rod can reduce the weight of the tappet. As a result, it is possible to use a valve train of lower rigidity, which can reduce the friction of the valve train and the fuel consumption of the engine.

Further, the groove serves to reduce the contact area between the tappet rod and the inner surface of the tappet groove of the cylinder block, so that the friction between the tappet rod and the inner surface of the tappet groove can be reduced. In addition, when the groove is formed in a spiral shape, the interaction between the spiral groove and the oil supplied for lubricating the inside of the tappet groove can further promote the rotation of the tappet when the tappet is lifted or lowered. As a result, the rotational motility of the tappet is improved, the lubricity between the tappet and the cam is improved, and the wear of the tappet or cam can be improved.

1 is a cross-sectional view illustrating a state in which a tappet of an engine is disposed between a camshaft and a push rod according to an embodiment of the present invention.
2 is an enlarged front view of the tappet shown in Fig.
3 is a front view showing a tappet of an engine according to another embodiment of the present invention.

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

The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "comprises", "having", and the like are used to specify that a feature, a number, a step, an operation, an element, a part or a combination thereof is described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

FIG. 1 is a cross-sectional view showing a state in which a tappet of an engine according to an embodiment of the present invention is disposed between a camshaft and a push rod, and FIG. 2 is an enlarged front view showing the tappet shown in FIG.

Referring to FIGS. 1 and 2, the engine according to the present embodiment may include a tappet 100, a camshaft 130, a cylinder block 140, and a push rod 150. The camshaft 130 may include a cam 132. The push rod 150 may be connected to a valve train that is a valve opening and closing mechanism. The valve train 150 may include a valve spring. The elastic force of the valve spring acts on the tappet 100 in the case of the push rod 150, so that the tappet 100 can maintain the contact state of the cam 132.

The tappet 100 may be disposed between the cam 132 of the camshaft 130 and the push rod 150. The tappet 100 may be movably disposed in the tappet groove 142 formed in the cylinder block 140. The cam 132 can be rotated by the power generated in the combustion chamber of the engine. The tappet 100 can be raised and lowered while being rotated by the rotational force of the cam 132. [ The tappet 100 can convert the rotational force of the cam 132 into a linear motion force and transmit the rotational force to the push rod 150. [ Oil can be supplied into the tappet groove 142 for lubrication between the tappet groove 142 and the tappet 100 and between the tappet 100 and the cam 132 when the engine is driven.

The tappet 100 may include a tappet head 110 and a tappet rod 120. The tappet head 110 can be in contact with the cam 132. The tappet 110 can be raised and lowered in the tappet groove 142 by the rotation of the cam 132. [

The tappet rod 120 may extend from the upper surface of the tappet head 110 toward the push rod 150. The tappet rod 120 can transmit the linear motion force converted from the rotational force of the cam 132 to the push rod 150. [ In this case, when the tappet 100 is driven only by the elevator, the contact between the tappet head 110 and the cam 132 is performed only at a predetermined position, so that the tappet head 110 may be worn away. The tappet head 110 and the cam 132 are eccentrically contacted with each other so that the tappet rod 120 can be rotated by the friction between the cam 132 and the tappet head 110 when the cam 132 rotates have. That is, the tappet rod 120 can be raised and lowered while rotating within the tappet groove 142. Therefore, oil for lubricating the rotation and elevation movement of the tappet rod 120 can be supplied between the outer circumferential surface of the tappet rod 120 and the inner surface of the tappet groove 142.

Grooves 122 may be formed on the outer circumferential surface of the tappet rod 120. In this embodiment, the groove 122 may have a spiral shape. The weight of the tappet rod 120 can be reduced by forming the groove 122. The tappet rod 120 with a relatively light weight can impart a relatively low rigidity to the valve spring of the valve train as compared with the conventional one. Further, the contact area between the outer peripheral surface of the tappet rod 120 and the inner peripheral surface of the tappet trench 142 can be reduced by the groove 122. Therefore, friction between the outer peripheral surface of the tappet rod 120 and the inner peripheral surface of the tappet groove 142 can be reduced. In addition, a sufficient amount of oil can be supplied through the grooves 122 to the contact surface between the tappet head 110 and the cam 132. The oil described above can generate a rotational force on the tappet rod 122 by interaction with the spiral groove 122 when the tappet rod 120 is lifted or lowered. As a result, the tappet rod 120 is smoothly rotated, and the power transmission motion of the tappet 100 can be improved.

Groove  Optimal Specification Experiment

The friction force of the valve train was measured while varying the depth d of the groove 122 while setting the pitch p of the groove 122 to 5 mm and the width w to 1 mm, Respectively.

Table 1

As shown in Table 1, when the depth d of the groove 122 is 1.0 mm to 1.5 mm and the pitch p of the groove 122 is 5 mm and the width w is 1 mm, It was found that the frictional force was the lowest.

The results of measuring the frictional force of the valve train while changing the pitch p and the width w of the groove 122 with the depth d of the groove 122 set at 1 mm are shown in Table 2 .

Table 2

The pitch p of the groove 122 is 5 mm to 7 mm and the width w of the groove 122 is 1 mm to 1.5 mm in the state that the depth d of the groove 122 is 1 mm, mm, the frictional force of the valve train is the lowest.

As a result, when the depth d of the groove 122 is 1 mm to 1.5 mm, the pitch p of the groove 122 is 5 mm to 7 mm, and the width w of the groove 122 is 1 mm to 1.5 mm, It can be seen that the friction force of the train is the lowest, and the tappet 100 can smoothly rotate.

3 is a front view showing a tappet of an engine according to another embodiment of the present invention.

Referring to FIG. 3, the tappet 100a of the present embodiment may include a tappet head 110a and a tappet rod 120a.

The groove 122a may be formed on the outer peripheral surface of the tappet rod 120a. In this embodiment, the groove 122a may be formed in the shape of a long hole along the axial direction of the tappet rod 120a. The weight of the tappet rod 120a can be reduced by forming the groove 122a. Further, the contact area between the outer peripheral surface of the tappet rod 120a and the inner peripheral surface of the tappet trench 142 can be reduced by the groove 122a. Therefore, friction between the outer circumferential surface of the tappet rod 120a and the inner circumferential surface of the tappet groove 142 can be reduced. In addition, a sufficient amount of oil can be supplied through the grooves 122a to the contact surface between the tappet head 110a and the cam 132. As a result, the tappet rod 120a is smoothly rotated, and the power transmitting motion of the tappet 100a can be improved.

As described above, according to the embodiments, the groove formed on the outer peripheral surface of the tappet rod can reduce the weight of the tappet. As a result, the spring of the valve train can be given a low rigidity and the contact pressure between the tappet head and the cam can be lowered. Thus, the friction of the tappet or the cam can be reduced. Further, the groove serves to reduce the contact area between the tappet rod and the inner surface of the tappet groove of the cylinder block, so that the friction between the tappet rod and the inner surface of the tappet groove can be reduced. In the case of the helical groove, the rotational force can be generated when the tappet is lifted or lowered by the interaction with the oil supplied into the tappet groove. As a result, the rotational motion of the tappet is improved, and the lubrication between the tappet and the cam can be improved.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. And changes may be made without departing from the spirit and scope of the invention.

100; Tappet 110; Tappet head
120; Tappet rod 122; Groove
130; Camshaft 132; cam
140; Cylinder block 142; Taffet Home
150; Push rod

Claims (5)

A tappet head in contact with the cam of the engine; And
And a tappet rod extending from the tappet head and being raised and lowered by a rotational force of the cam, the groove being formed on an outer circumferential surface of the tappet rod. The tappet of claim 1, wherein the groove is helical. 3. The tappet of claim 2, wherein the helical groove has a depth of 1 mm to 1.5 mm, a pitch of 5 mm to 7 mm, and a width of 1 mm to 1.5 mm. The tappet of an engine according to claim 1, wherein the groove is formed as a long hole along the axial direction of the tappet rod. A cam rotated by the power generated in the combustion chamber;
A tappet head including a tappet head in contact with the cam, and a tappet rod extending from the tappet head and having an outer circumferential surface that is raised and lowered while being rotated by a rotational force of the cam; And
And a cylinder block having a tappet groove for allowing the tappet to be lifted and lowered.

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