Patent Description:
Patent Literature <NUM> discloses a tappet constructed as a valve lifter. The tappet has a cup-like shape as a whole, and a lower end portion of a push rod abuts and is supported on an inner bottom portion of the tappet. An upper end portion of the push rod supports an end of a rocker arm. The other end of the rocker arm abuts on an upper end portion of an exhaust valve.

A lower surface of the tappet is a flat sliding contact surface and is in contact with a cam. When the cam rotates, the tappet and the push rod are raised and lowered, and accordingly, the rocker arm swings to open and close the exhaust valve.

<CIT> discloses a valve tappet for a valve drive of an internal combustion engine, comprising a cup-shaped housing and several inner parts, at least one of which is each provided with a guide sleeve for receiving a lash adjuster. In order to create a valve tappet for a valve drive of an internal combustion engine which, while being lightweight, enables reliable guidance of the lash adjuster, several inner parts each have a guide sleeve. The guide sleeves are arranged axially one behind the other.

<CIT> discloses a tappet device in a valve operating mechanism of an engine constructed so as to transmit movement of a tappet, which is driven by a cam, to a suction / exhaust valve through a bush rod and a rocker arm and to open and close the suction / exhaust valve, wherein the tappet has a container-like structure opened at its upper end so as to accommodate the lubricating oil therein, a filter is provided inside the tappet, and the lubricating oil filtered by the tappet is supplied to lubricate the cam. <CIT> discloses a lubricating device for an engine which can efficiently lubricate the abutting portion and the sliding portion around the rocker arm and the contact portion between the tappet and the cam without generating scuffing only by slightly machining it.

An automatic adjustment function for valve clearance can be exhibited by incorporating a lash adjuster into a cap of the tappet. This type of lash adjuster includes a cylindrical body and a plunger housed in the body, and the plunger is configured to move vertically with respect to the body in response to fluctuation of hydraulic pressure.

In the case where the lash adjuster is incorporated into the cup of the tappet, if an inner peripheral surface of the body is configured to abut against an inner peripheral surface of the cup, there is a circumstance that lubricating oil falling along the push rod and the like is blocked by the lash adjuster and prevented from falling further. Therefore, there is a concern that the lubricating oil may not reach the cam and the lubricating oil may not be sufficiently fed between the cam and a sliding contact surface of the tappet, with the result that lubrication of the cam may become insufficient or inadequate.

The present invention has been completed based on the above circumstances, and it is an object of the present invention to provide a tappet capable of supplying lubricating oil to a cam even with a tappet including a lash adjuster. This object is achieved by a tappet having the features of claim <NUM>. Preferred embodiments are defined in the respective dependent claims.

A tappet of the present invention includes a lash adjuster and a tappet body into which the lash adjuster is inserted and incorporated. The lash adjuster has a plunger having a top portion on which a lower end portion of a push rod is slidable, and a body in which the plunger is housed so as to be vertically movable. The tappet body has: a lower surface portion which slidingly contacts a cam; an outer peripheral surface portion which is slidable on a tappet guide; a receiving surface portion which is located inside the outer peripheral surface portion, receives lubricating oil, and faces upward; an assembly hole which is located inside the outer peripheral surface portion, extends vertically, and has an upper end opened to the receiving surface portion and a lower end closed, and in which the body is inserted and assembled; a receiving space which is located inside the outer peripheral surface portion and opened to an upside of the receiving surface portion; and an oil guide passage which is located at the outer peripheral surface portion or between the outer peripheral surface portion and the assembly hole, and extends so as to guide the lubricating oil received by the receiving surface portion to the cam.

In the state where the body of the lash adjuster is inserted and assembled into the assembly hole of the tappet body, the lubricating oil received by the receiving surface portion from the push rod side can pass through the oil guide passage and reach the cam, so that the lubricating oil can be supplied to the cam.

Furthermore, since the lash adjuster is merely inserted into the assembly hole of the tappet body, assembling operation can be easily performed, and, in addition, the existing (general-purpose) lash adjuster can be used as it is.

Furthermore, a predetermined amount of the lubricating oil can be stored in the receiving space above the receiving surface portion inside the tappet body.

In the present invention and the present description, the "vertically" or "vertical direction" is not limited to a strict vertical direction, but includes a direction inclined with respect to the vertical direction.

Preferred embodiments of the present invention are shown below.

The oil guide passage has an oil guide groove extending vertically in the outer peripheral surface portion. According to this, lubricating oil from a push rod can reach a cam quickly and reliably along the oil guide groove. Furthermore, since the oil guide groove is arranged at an outer peripheral surface portion of a tappet body, ease of machining can be ensured.

The tappet body may preferably have an oil guide hole which penetrates a peripheral wall defining an outer periphery of the receiving space and communicates with an upper end portion of the oil guide groove. According to this, the lubricating oil can flow from the receiving space to the oil guide groove through the oil guide hole. Therefore, the lubricating oil can be prevented from overflowing from an upper end of the tappet body.

The oil guide passage may preferably have a circumferential groove which is provided in a lower end portion of the outer peripheral surface portion, extends circumferentially and communicates with a lower end portion of the oil guide groove. According to this, even if the tappet body rotates and the oil guide groove is displaced to a position deviated from a sliding region of the cam, the lubricating oil can be spread from the oil guide groove along the circumferential groove and can reach the cam.

A lower surface of the circumferential groove may preferably be a downslope which is inclined downward from an inner surface of the circumferential groove toward outside. According to this, the lubricating oil can smoothly and quickly reach the cam along the downslope of the circumferential groove.

The tappet body may preferably have a retaining portion for retaining the lubricating oil inside the circumferential groove. According to this, since the lubricating oil is temporarily received by the retaining portion and then can be released toward the cam, the reliability of causing the lubricating oil to reach the cam can be enhanced.

The tappet body may preferably have a baffle portion which is provided on a lower surface of the circumferential groove and inclined upward from the inner surface of the circumferential groove toward outside, and the retaining portion may be constituted by the baffle portion. According to this, the retaining portion can be provided without increasing the number of parts.

The retaining portion may preferably be constituted by a ring member which is attached to the tappet body so as to cover an opening of the circumferential groove. According to this, it is possible to adjust an amount of the lubricating oil retained in the circumferential groove, the position where the lubricating oil is released to the cam, and the like, by the form of the ring member.

The oil guide passage may preferably have a communication hole penetrating an outer peripheral portion of the assembly hole of the tappet body from a side surface of the assembly hole to the outer peripheral surface portion. According to this, the lubricating oil can be caused to flow between the assembly hole and the outer peripheral surface portion via the communication hole. Furthermore, when the lash adjuster is inserted into the assembly hole of the tappet body, air (compressed air) in the assembly hole can be vented through the communication hole.

Embodiment <NUM> of the present invention will be described with reference to <FIG>. A tappet <NUM> according to Embodiment <NUM> is provided in a valve gear of an internal combustion engine, and illustrates a valve lifter of an OHV type engine.

As shown in <FIG>, the valve gear includes: a valve <NUM> which is incorporated so as to be able to open and close an intake or exhaust port <NUM> of the cylinder head <NUM> and has an upper end portion disposed protruding above the cylinder head <NUM>; a rocker arm <NUM> having one lengthwise end portion which abuts against the upper end portion of the valve <NUM>; a push rod <NUM> having an upper end portion which abuts against the other lengthwise end portion of the rocker arm <NUM> via an adjusting screw <NUM>; a lash adjuster <NUM> against which a lower end portion of the push rod <NUM> abuts; and a tappet body <NUM> housing the lash adjuster <NUM>. Among these, the tappet <NUM> is constituted of the lash adjuster <NUM> and the tappet body <NUM>.

The valve <NUM> is inserted through a valve guide hole <NUM> so as to be vertically slidable, and is biased in a valve closing direction (a direction for lifting one end portion of the rocker arm <NUM>) by a biasing member <NUM> such as a coil spring.

The rocker arm <NUM> is swung with a rocker shaft <NUM> serving as a fulcrum which penetrates a lengthwise middle portion (a portion between lengthwise one end portion and the other end portion) of the rocker arm <NUM>, thereby performing the function of opening and closing the valve <NUM>. The adjusting screw <NUM> penetrates the other lengthwise end portion of the rocker arm <NUM> and is screwed into a nut <NUM>, and an amount of downward protrusion thereof from the other end portion of the rocker arm <NUM> is adjustable according to screwing into the nut <NUM>.

The push rod <NUM> is a rod-like member elongated vertically, and is housed in a rod housing portion (not shown). The upper end portion of the push rod <NUM> is a hemispherical upper end recess <NUM> opened upward. A lower end portion of the adjusting screw <NUM> is slidably supported on the upper end recess <NUM>. The lower end portion of the push rod <NUM> is a hemispherical lower end recess <NUM> opened downward. The lower end recess <NUM> is slidably supported on a top portion <NUM> of a plunger <NUM>, to be described later, of the lash adjuster <NUM>.

A rod hole <NUM> is provided in a center of the push rod <NUM> so as to penetrate in the axial direction. An upper end of the rod hole <NUM> is opened at a central portion of the upper end recess <NUM>, and a lower end of the rod hole <NUM> is opened at a central portion of the lower end recess <NUM>. Here, lubricating oil (hydraulic oil) supplied to the rocker arm <NUM> flows from a sliding region of the adjusting screw <NUM> into the rod hole <NUM> through the upper end recess <NUM>, and descends along an inner surface of the rod hole <NUM> to reach the lower end recess <NUM>, and lubricates the top portion <NUM> of the plunger <NUM> sliding on the lower end recess <NUM>. Further, a part of the lubricating oil flows down along an outer surface of the push rod <NUM> from the upper side where the rocker arm <NUM> is located, and reaches the tappet <NUM>.

Next, the tappet <NUM> will be described. As shown in <FIG>, the lash adjuster <NUM> constituting the tappet <NUM> includes a bottomed cylindrical body <NUM> and the bottomed cylindrical plunger <NUM> inserted in the body <NUM> so as to be vertically movable. The plunger <NUM> has a valve hole <NUM> in a bottom wall portion thereof and has the hemispherical top portion <NUM> at an upper end portion of a peripheral wall portion thereof. A radius of curvature of an outer peripheral surface (convex spherical surface) of the top portion <NUM> is smaller than a radius of curvature of an inner peripheral surface (concave spherical surface) of the lower end recess <NUM>. The center of the top portion <NUM> is provided with a top hole <NUM> penetrating therethrough.

The inside of the plunger <NUM> is constituted as a low pressure chamber <NUM>. The lower side of the inside of the body <NUM> is constituted as a high pressure chamber <NUM> defined between the lower side and the bottom wall portion of the plunger <NUM>. The lubricating oil is introduced from the rod hole <NUM> of the push rod <NUM> through the top hole <NUM> and stored in the low pressure chamber <NUM>. The lubricating oil of the low pressure chamber <NUM> is filled into the high pressure chamber <NUM> through the valve hole <NUM>.

The high pressure chamber <NUM> houses a spherical valve body <NUM>, a cage-shaped retainer <NUM>, a first spring <NUM> and a second spring <NUM>. The valve body <NUM> is housed in the retainer <NUM> and disposed so as to be able to open and close the valve hole <NUM>. The first spring <NUM> is housed in the retainer <NUM> and biases the valve body <NUM> upward (in a direction for closing the valve hole <NUM>). The second spring <NUM> biases the retainer <NUM> upward. In Embodiment <NUM>, the known lash adjuster <NUM> is used as it is.

The tappet body <NUM> has a cup-like shape as a whole and includes a circular bottom wall <NUM> and a peripheral wall <NUM> rising upward from an outer peripheral edge of the bottom wall <NUM>. The tappet body <NUM> is inserted into a tappet guide hole <NUM> provided in a housing <NUM> at an upper portion of a cylinder block, and is inserted to be vertically slidable.

Specifically, the tappet body <NUM> has: an outer peripheral surface portion <NUM> constituting an outer peripheral surface of the peripheral wall <NUM>; a lower surface portion <NUM> constituting a lower surface of the bottom wall <NUM>; a receiving surface portion <NUM> provided inside the outer peripheral surface portion <NUM> and located at the same height as a vertically middle portion of the outer peripheral surface portion <NUM> and facing upward; and a receiving space <NUM> provided inside of an upper portion of the outer peripheral surface portion <NUM> and opened to the upside of the receiving surface portion <NUM>. In other words, the receiving space <NUM> is partitioned by an upper portion of the peripheral wall <NUM> and the receiving surface portion <NUM>. The lower surface portion <NUM> is a flat surface disposed substantially horizontally. The receiving surface portion <NUM> also has a portion disposed substantially horizontally. The outer peripheral surface portion <NUM> is formed to have a circular cross section and is slidable on an inner peripheral surface of the tappet guide hole <NUM>.

As shown in <FIG>, the tappet body <NUM> has an assembly hole <NUM> which extends vertically and has a circular cross section. The assembly hole <NUM> has an upper end which is opened to a radially central portion of the receiving surface portion <NUM> and a lower end which is closed and defines an upper surface of the bottom wall <NUM>. The lash adjuster <NUM> is inserted from the receiving space <NUM> side into the assembly hole <NUM> of the tappet body <NUM> and assembled.

The lower surface portion <NUM> of the tappet body <NUM> is slidably in contact with a cam <NUM> disposed below. An inner peripheral surface of the assembly hole <NUM> of the tappet body <NUM> includes fitting surfaces <NUM> which are provided at two positions spaced from each other in the vertical direction and have the smaller diameters than adjacent upper and lower regions. The fitting surface <NUM> of the tappet body <NUM> is disposed to be able to abut against the body <NUM> of the lash adjuster <NUM> along a circumferential direction. As a result, the lash adjuster <NUM> is held in a state where a free movement in the radial direction with respect to the tappet body <NUM> is restricted.

The peripheral wall <NUM> of the tappet body <NUM> is provided with an oil guide passage <NUM> for receiving the lubricating oil flowing down along the outer surface of the push rod <NUM> and guiding the lubricating oil to the cam <NUM>. In Embodiment <NUM>, the oil guide passage <NUM> is constituted of an oil guide groove <NUM> and an oil guide hole <NUM>.

As shown in <FIG>, the oil guide groove <NUM> is recessed in the outer peripheral surface portion <NUM> of the peripheral wall <NUM> and has a U-shaped cross section or a squared U-shaped cross section extending vertically. The oil guide grooves <NUM> are formed in pairs at both radial end portions in the outer peripheral surface portion <NUM> of the peripheral wall <NUM>. As shown in <FIG>, the oil guide grooves <NUM> are provided in a thick-walled portion of the peripheral wall <NUM> outside the assembly hole <NUM>. A lower end of the oil guide groove <NUM> is closed at the same position as an inner surface of the bottom wall <NUM> or slightly above the inner surface of the bottom wall <NUM>.

The oil guide hole <NUM> has a circular cross-sectional shape coaxially penetrating both radial end portions of a thin-walled portion of the peripheral wall <NUM> from a position facing an inner space to the outer peripheral surface portion <NUM>, and communicates with an upper end portion of the oil guide groove <NUM>. The oil guide hole <NUM> is located slightly above the receiving surface portion <NUM>. The opening diameter of the oil guide hole <NUM> is slightly larger than a groove width of the oil guide groove <NUM>. When the tappet body <NUM> is inserted into the tappet guide hole <NUM>, a portion of the oil guide passage <NUM> excluding a lower end portion of the oil guide groove <NUM> is closed by the tappet guide hole <NUM> so as to face the inner peripheral surface of the tappet guide hole <NUM>. In Embodiment <NUM>, the oil guide hole <NUM> is formed in the peripheral wall <NUM> by boring process, and the oil guide groove <NUM> is formed in the outer peripheral surface portion <NUM> of the peripheral wall <NUM> by cut-out process.

Next, a valve gear mechanism will be described. When the cam <NUM> rotates, the tappet body <NUM> in contact with the cam <NUM> is slidingly displaced in the tappet guide hole <NUM> in the vertical direction, and the push rod <NUM> is raised and lowered via the lash adjuster <NUM>. The rising and lowering operation of the push rod <NUM> is transmitted to the rocker arm <NUM> via the adjusting screw <NUM>, whereby the rocker arm <NUM> is swung and displaced so that one lengthwise end portion of the rocker arm <NUM> is moved up and down, with the result that the valve <NUM> is opened and closed.

Here, when the tappet body <NUM> is raised and accordingly the plunger <NUM> is strongly pressed downward from the push rod <NUM>, the valve body <NUM> closes the valve hole <NUM> and thereby the plunger <NUM> and the body <NUM> are turned into a rigid body, so that lowering of the plunger <NUM> is restricted. When the tappet body <NUM> is lowered and accordingly pressure acting on the plunger <NUM> is reduced, the second spring <NUM> pushes up the plunger <NUM> and thereby the volume of the high pressure chamber <NUM> is increased, so that the pressure of the high pressure chamber <NUM> is reduced. As a result, a force for biasing the valve body <NUM> in the valve closing direction is reduced, and the valve body <NUM> opens the valve hole <NUM>, so that the lubricating oil in the low pressure chamber <NUM> is transferred to the high pressure chamber <NUM>. Thus, lift force of the cam <NUM> is attenuated and transmitted to the push rod <NUM> and the rocker arm <NUM> via the lash adjuster <NUM>, whereby valve clearance is automatically adjusted.

Next, a lubricating path of the lubricating oil from the rocker arm <NUM> side to the cam <NUM> side will be described.

The lubricating oil flowing through an oil passage <NUM> of the rocker shaft <NUM> flows to the other lengthwise end portion of the rocker arm <NUM>. A part of the lubricating oil lubricates a lubricating region between the lash adjuster <NUM> and the adjusting screw <NUM> and flows into the rod hole <NUM>, and the rest flows down along the outer surface of the push rod <NUM>. The lubricating oil flowing down along the outer surface of the push rod <NUM> flows from the outer surface of the lower end recess <NUM> into the inside of the tappet body <NUM>.

The lubricating oil flowing into the inside of the tappet body <NUM> is received by the receiving surface portion <NUM> and can be stored in the receiving space <NUM> until reaching a lower limit height of the oil guide hole <NUM>. In this case, since there is substantially no gap formed between the fitting surface <NUM> of the tappet body <NUM> and the body <NUM>, the lubricating oil does not easily pass therethrough.

The lubricating oil stored in the receiving space <NUM> above the receiving surface portion <NUM> flows into the oil guide hole <NUM> and then flows to the upper end portion of the oil guide groove <NUM>, and further slides down from the upper end portion of the oil guide groove <NUM> along a groove surface of the oil guide groove <NUM> (see arrows in <FIG>). However, the lubricating oil may drop from the outer surface of the lower end recess <NUM> and directly enter the oil guide hole <NUM> without via the receiving surface portion <NUM>. The lubricating oil reaching the lower end portion of the oil guide groove <NUM> further drops and adheres to a cam surface <NUM> of the cam <NUM>, thereby lubricating a sliding region between the lower surface portion <NUM> of the tappet body <NUM> and the cam surface <NUM> of the cam <NUM>.

As described above, according to Embodiment <NUM>, even if the lash adjuster <NUM> is internally fitted to the tappet body <NUM> so that the lubricating oil cannot descend inside the tappet body <NUM> to reach the cam <NUM> side, the oil guide passage <NUM> extending from the oil guide hole <NUM> to the cam <NUM> side through the oil guide groove <NUM> is secured. Therefore, sufficient lubricating oil can be supplied to the cam <NUM>.

Since the lash adjuster <NUM> is merely inserted into the assembly hole <NUM> of the tappet body <NUM>, assembling operation can be easily performed, and, in addition, the existing (general-purpose) lash adjuster can be used as it is. In addition, a predetermined amount of lubricating oil can be stored in the receiving space <NUM> above the receiving surface portion <NUM> inside the tappet body <NUM>.

Furthermore, since the oil guide groove <NUM> is provided in the outer peripheral surface portion <NUM> of the tappet body <NUM>, machining becomes easier as compared with a case where the oil guide groove <NUM> is provided in an inner peripheral surface of the tappet body <NUM>. Furthermore, since the oil guide hole <NUM> is provided so as to penetrate the peripheral wall <NUM> of the tappet body <NUM> to communicate with the upper end portion of the oil guide groove <NUM>, the lubricating oil passes sequentially from the receiving space <NUM> through the oil guide hole <NUM> and the oil guide groove <NUM>, and can reach the cam <NUM> side quickly. In addition, the lubricating oil can be prevented from overflowing from the upper end of the peripheral wall <NUM> of the tappet body <NUM> and being spread around the periphery.

<FIG> and <FIG> show Embodiment <NUM> of the present invention. Embodiment <NUM> differs from Embodiment <NUM> in that an oil guide passage 30A includes a circumferential groove <NUM>. Embodiment <NUM> is the same as Embodiment <NUM> except for this point, and the description overlapping with Embodiment <NUM> is omitted. In the following description, the structurally same or corresponding portions as or to those in Embodiment <NUM> are denoted by the same reference signs as in Embodiment <NUM>.

The circumferential groove <NUM> has an annular shape extending over the entire circumference of the outer peripheral surface portion <NUM> of the tappet body <NUM> and communicates with the lower end portions of the oil guide grooves <NUM> at both radial end portions. The depth of the circumferential groove <NUM> is greater than the depth of the oil guide groove <NUM> and greater than the thickness of a thin-walled portion of the tappet body <NUM>.

An inner surface <NUM> of the circumferential groove <NUM> is disposed along the vertical direction. A lower surface of the circumferential groove <NUM> is a downslope <NUM> which is inclined downward from the inner surface <NUM> toward outside in a tapered shape. An upper surface of the circumferential groove <NUM> is an upslope <NUM> which is inclined upward from the inner surface <NUM> toward outside in a tapered shape. Each of the downslope <NUM> and the upslope <NUM> has an inclination angle larger than <NUM> degrees with respect to a horizontal axis extending along the horizontal direction. The downslope <NUM> of the circumferential groove <NUM> faces the lower end of the tappet body <NUM> and is disposed at a position close to the lower surface portion <NUM>. The upslope <NUM> of the circumferential groove <NUM> intersects with the lower end of the oil guide groove <NUM>, and the oil guide groove <NUM> communicates with the upslope <NUM> in a cutout manner.

Here, the diameter dimension of the lower surface portion <NUM> of the tappet body <NUM> is made larger than the width dimension of the cam surface <NUM> of the cam <NUM>, and the lower surface portion <NUM> of the tappet body <NUM> has a portion protruding outward in the width direction of the cam surface <NUM> of the cam <NUM>. For this reason, when the tappet body <NUM> is rotated and displaced around the axis in the tappet guide hole <NUM>, the oil guide groove <NUM> may be displaced to a position deviated from the cam surface <NUM> of the cam <NUM>. In this case, there is a concern that the lubricating oil may drop down and cannot flow from the oil guide groove <NUM> to the cam surface <NUM> of the cam <NUM>. However, according to Embodiment <NUM>, even if the oil guide groove <NUM> is displaced to the position deviated from the cam surface <NUM> of the cam <NUM> in the circumferential direction, the lubricating oil flows from the lower end of the oil guide groove <NUM> to the circumferential groove <NUM>, and is spread circumferentially along the groove surface of the circumferential groove <NUM>, so that the spread lubricating oil can reach the cam surface <NUM> of the cam <NUM>. As a result, sufficient lubricating oil can be supplied to the cam <NUM>. In particular, in Embodiment <NUM>, since the lower surface of the circumferential groove <NUM> is the downslope <NUM>, the lubricating oil can smoothly and quickly reach the cam surface <NUM> of the cam <NUM> from the downslope <NUM>.

<FIG> shows Embodiment <NUM> of the present invention. Embodiment <NUM> differs from Embodiment <NUM> in the form of a circumferential groove 33B of an oil guide passage 30B, and the tappet body <NUM> has a retaining portion <NUM> which temporarily receives lubricating oil from an oil guide groove <NUM> inside the circumferential groove 33B. The others are the same as in Embodiment <NUM>.

The circumferential groove 33B has a baffle portion <NUM> having a reverse tapered shape which is formed on the lower surface thereof and is gradually inclined upward from the inner surface <NUM> toward outside. The baffle portion <NUM> is formed as an undercut over the entire circumference of the circumferential groove 33B. The retaining portion <NUM> is constituted by the baffle portion <NUM>, and the lubricating oil can be stored in a retaining space <NUM> which is defined between the inner surface <NUM> of the circumferential groove 33B and the baffle portion <NUM> and has a V-shaped cross section.

According to Embodiment <NUM>, the lubricating oil having dropped from the oil guide groove <NUM> is temporarily received in the retaining space <NUM>, and the received lubricating oil is spread in the circumferential direction along the baffle portion <NUM> with the rotation of the tappet body <NUM>, and can reach the cam surface <NUM> of the cam <NUM>. Therefore, it is possible to enhance the reliability of causing the lubricating oil to reach the cam surface <NUM> of the cam <NUM>. Furthermore, since the baffle portion <NUM> serving as the retaining portion <NUM> is provided integrally with the tappet body <NUM>, the number of parts is not increased, so that parts management becomes easy.

<FIG> shows Embodiment <NUM> of the present invention. Embodiment <NUM> differs from Embodiment <NUM> in that a ring member <NUM> separate from a tappet body <NUM> is attached as the retaining portion <NUM>. The others are the same as in Embodiment <NUM>.

The ring member <NUM> has an annular shape with ends as a whole (C shape in plan view) and can be elastically deformed via a gap between both ends. The ring member <NUM> is elastically attached to the tappet body <NUM> and is disposed so as to cover an opening of a circumferential groove <NUM>. The ring member <NUM> is provided with a plurality of oil outflow holes <NUM> spaced apart from one another in the circumferential direction. In the illustrated case, the oil outflow holes <NUM> are opened to a lower end edge of the ring member <NUM>.

According to Embodiment <NUM>, with the rotation of the tappet body <NUM>, the lubricating oil flowing out of the oil guide groove <NUM> is received by an inner peripheral surface of the ring member <NUM>, and thereafter the lubricating oil flows out of the oil outflow holes <NUM> with the rotation of the tappet body <NUM>, and can reach the cam surface <NUM> of the cam <NUM>. Thus, the lubricating oil can be reliably supplied to the cam <NUM>. By removing the ring member <NUM> from the tappet body <NUM>, the tappet of Embodiment <NUM> also can be used as a form of Embodiment <NUM>.

<FIG> shows Embodiment <NUM> of the present invention. Although Embodiment <NUM> has the circumferential groove <NUM> similarly to Embodiment <NUM>, an oil guide passage 30D except the circumferential groove <NUM> is different from that of Embodiment <NUM>.

The tappet body <NUM> does not have the oil guide hole <NUM> of Embodiment <NUM> and has the oil guide passage 30D provided in a radially thick-walled portion between an assembly hole <NUM> of a peripheral wall <NUM> and an outer peripheral surface portion <NUM>. The oil guide passage 30D has an oil guide groove 31D which extends vertically side by side with the assembly hole <NUM> and has an upper end opened to a receiving surface portion <NUM>, and a communication hole <NUM> which intersects with a lower end of the oil guide groove 31D and penetrates the thick-walled portion of the peripheral wall <NUM> in a radial direction from a side surface of the assembly hole <NUM> to the outer peripheral surface portion <NUM> (here, the inner surface <NUM> of the circumferential groove <NUM>). The receiving surface portion <NUM> of the tappet body <NUM> is formed to be slightly curved radially inward in a concave-curved shape.

In Embodiment <NUM>, the lubricating oil having dropped from the push rod <NUM> side is received by the receiving surface portion <NUM>, then flows from the receiving surface portion <NUM> into the oil guide groove 31D, then further passes sequentially from the oil guide groove 31D through the communication hole <NUM> and the circumferential groove <NUM>, and can reach the cam surface <NUM> of the cam <NUM>. In this case, the lubricating oil can be stored in a curved inner portion of the receiving surface portion <NUM> in a receiving space <NUM>. However, the lubricating oil may not necessarily be stored in the receiving space <NUM>, and may flow directly into the oil guide groove 31D from the push rod <NUM> side without via the receiving surface portion <NUM>.

According to Embodiment <NUM>, the lubricating oil having dropped from the push rod <NUM> side can be more quickly supplied to the cam surface <NUM> of the cam <NUM>. Furthermore, when a lash adjuster <NUM> is inserted into the assembly hole <NUM> of the tappet body <NUM>, the communication hole <NUM> can be used as an air-vent path for venting air present inside the assembly hole <NUM>.

<FIG> shows Embodiment <NUM> of the present invention. Embodiment <NUM> differs from Embodiment <NUM> in that the peripheral wall <NUM> does not include the oil guide hole <NUM>.

In Embodiment <NUM>, an upper portion of the peripheral wall <NUM> defining an outer periphery of a receiving space <NUM> is shorter than that of Embodiment <NUM>. An oil guide passage 30E is constituted by oil guide grooves 31E formed in pairs in the radial direction in an outer peripheral surface portion <NUM> of a tappet body <NUM>. The oil guide groove 31E extends vertically and has an upper end opened to the upper end of the peripheral wall <NUM> and a lower end closed at a position near the bottom wall <NUM>.

In Embodiment <NUM>, the lubricating oil from the push rod <NUM> side is stored in the receiving space <NUM> above the receiving surface portion <NUM> in a full state, then flows over the upper end of the peripheral wall <NUM> into the oil guide groove 31E, and can reach the cam surface <NUM> of the cam <NUM> from the oil guide groove 31E. According to Embodiment <NUM>, it is not necessary to perform machining to bore the oil guide hole <NUM> in the peripheral wall <NUM>, and in addition, the lubricating oil can be sufficiently stored in the receiving space <NUM>.

<FIG> shows Embodiment <NUM> of the present invention. In Embodiment <NUM>, a form of an oil guide passage 30F is slightly different from that of Embodiment <NUM>.

In Embodiment <NUM>, an oil guide hole 32F is provided so as to penetrate a thin-walled portion of a peripheral wall <NUM> from the receiving space <NUM> side to the outer peripheral surface portion <NUM>; however, unlike Embodiment <NUM>, the oil guide hole 32F is opened to an upper end of the peripheral wall <NUM>. In other words, the oil guide hole 32F has a form cut out in a concave shape at the upper end of the peripheral wall <NUM>. According to Embodiment <NUM>, lubricating oil stored in the receiving space <NUM> can pass through the concave oil guide hole 32F and flow into an oil guide groove 31F. The others are the same as in Embodiment <NUM>.

Claim 1:
A tappet (<NUM>) comprising:
a lash adjuster (<NUM>); and
a tappet body (<NUM>) into which the lash adjuster (<NUM>) is inserted and incorporated,
wherein
the lash adjuster (<NUM>) has a plunger (<NUM>) having a top portion on which a lower end portion of a push rod (<NUM>) is slidable, and a body (<NUM>) in which the plunger (<NUM>) is housed so as to be vertically movable, and
the tappet body (<NUM>) has
a lower surface portion which slidingly contacts a cam (<NUM>),
an outer peripheral surface portion (<NUM>) which is slidable on a tappet guide,
a receiving surface portion (<NUM>) which is located inside the outer peripheral surface portion (<NUM>), receives lubricating oil, and faces upward,
an assembly hole (<NUM>) which is located inside the outer peripheral surface portion (<NUM>), extends vertically, and has an upper end opened to the receiving surface portion (<NUM>) and a lower end closed, and in which the body (<NUM>) is inserted and assembled,
a receiving space (<NUM>) which is located inside the outer peripheral surface portion (<NUM>) and opened to an upside of the receiving surface portion (<NUM>), and
an oil guide passage (<NUM>) which is located at the outer peripheral surface portion (<NUM>) or between the outer peripheral surface portion (<NUM>) and the assembly hole (<NUM>), and extends so as to guide the lubricating oil received by the receiving surface portion (<NUM>) to the cam (<NUM>),
characterized in that
the oil guide passage (<NUM>) has an oil guide groove (<NUM>) extending vertically in the outer peripheral surface portion (<NUM>).