JP2003343222A - Valve train of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a detent member body for restricting peripheral rotation of a tappet constituting a variable valve train from biting into a guide groove in which the tappet fits, hold down upsizing of the engine, and facilitate adjustment of a tappet clearance and measurement in assembling the engine. <P>SOLUTION: The detent member body 6 is fit loose in a pin 26 so that the main body 6 is swingable around the axis of the pin 26 to expand the contact area with the grid groove 3a so as to prevent the dent member body 6 from wearing out. Further, formation of the groove 3a is facilitated by peripherally setting off the position of the detent member at a predetermined angle from the axial direction of a camshaft. The camshaft end face of the dent member body 6 is extended approximately to the height of tappet slide face 1a on a cam 4a. Measurement and control of the tappet clearance are facilitated by taking the end face as a reference face for measurement of the tappet height. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine valve operating system.

[0002]

2. Description of the Related Art In order to improve fuel economy and output of an automobile engine, a variable valve operating device has been devised for changing the opening / closing timing of an intake valve and an exhaust valve with respect to a crank angle, the lift amount, etc. according to operating conditions. ing. For example, 1
It is possible to have a so-called split tappet in which a plurality of cams are provided for one valve and the tappet is divided into a plurality of cams so as to make sliding contact with a specific cam among the plurality of cams according to the operating state. The variable valve device is one of them.

As an example, German published patent DE 1
9721208 (Fig. 8). FIG. 8 shows a cross section of the central portion of the tappet 82 as viewed in the direction perpendicular to the camshaft axis. This is a tappet having an inner tappet 82a and an annular outer tappet 82b arranged so as to surround the inner tappet 82a, and a mechanism capable of switching the inner tappet 82a and the outer tappet 82b in the hole portion 83 to an unlocked state. The tappet outer peripheral wall 85 is provided with a pin member 86 in the same direction as the camshaft axis. This pin member 86
Is a detent member that prevents the tappet 82 from rotating in the circumferential direction within a tappet guide hole provided in the cylinder head. Further, it is difficult to increase the size of the detent member from the viewpoints of downsizing the engine, increasing the number of valves, and reducing the weight of the tappet.

On the other hand, the cylinder head for accommodating the tappet is often made of aluminum alloy because of its light weight and heat dissipation, and it is used as a guide groove of a tappet guide hole which is in sliding contact with the rotation preventing member at the time of engine start or high speed rotation. The wear is likely to progress between them, and in particular, there is a possibility of causing a problem that the detent member is caught due to the depression of the guide groove.

The tappet shown in FIG. 8 has a built-in hydraulic lash adjuster (HLA) so that the tappet clearance can be automatically adjusted by hydraulic pressure. However, in order to reduce the weight and cost of the tappet, the HLA is used. A so-called mechanical lash adjuster (MLA), which is not provided, is used. Although this MLA type is not shown in the drawings, the method for measuring and adjusting the tappet clearance will be explained. First, the reference shim is placed on the valve stem end to accommodate the tappet in the tappet guide hole, and the cam is assembled to the cylinder head. After attaching, a thickness gauge (gap gauge) is inserted between the top plate (sliding contact surface with the cam) of the tappet and the cam, and it is measured whether the tappet clearance is within a predetermined value. If the thickness is not within the predetermined value, the shim is replaced with a shim having a thickness so that the predetermined value is obtained. In the case of a split tappet, this work is difficult to insert the thickness gauge due to the plurality of cams, resulting in extremely poor workability.

[0006]

SUMMARY OF THE INVENTION In view of the above, the present invention is directed to a tappet which constitutes a valve operating device for an engine, wherein a detent member main body portion for restricting rotation of the tappet in the circumferential direction is provided.
Prevents problems such as being caught in the guide groove that is provided on the peripheral wall of the tappet guide that stores the tappet and that is in sliding contact with the tappet rotation-stop member main body, suppresses the length of the engine in the camshaft direction, and allows engine assembly. The objective is to facilitate the adjustment and measurement of tappet clearance at the time.

[0007]

According to a first aspect of the present invention, there is provided a valve operating system for an engine, wherein a tappet having a substantially cylindrical outer shape is formed of a plurality of tappet constituent members, and the tappet constituent members are engaged and disengaged. In an engine valve operating device including a variable mechanism that changes a valve lift characteristic by including a lock mechanism, a tappet guide hole that has a guide groove extending in a sliding direction of a tappet and that accommodates a tappet is formed in a cylinder head, A detent member that is provided on the tappet and that restricts rotation of the tappet in the circumferential direction is fitted into the guide groove, and the detent member has a sliding contact surface that is inserted into the guide groove and extends in the sliding direction. The main body includes a main body and a shaft that supports the main body on the tappet, and the main body is swingable around the axis of the shaft.

According to the first aspect of the present invention, since the detent member supported by the tappet is fitted in the guide groove formed in the tappet guide hole of the cylinder head, the tappet rotates in the circumferential direction. Therefore, the valve lift characteristic which is made possible by the engagement and disengagement of the plurality of tappet constituent members can be maintained with high reliability. Further, the rotation preventing member has a structure including a main body portion having a sliding contact surface which is fitted into the guide groove and extends in the sliding direction, and a shaft portion which supports the main body portion on the tappet, and the rotation preventing member main body. Since the portion is swingable around the axis of the shaft portion, the area in which the guide groove comes into contact with the sliding contact surface of the detent member main body portion increases, and the guide groove sags, abnormal wear, or the detent member. Problems such as the main body biting into the guide groove can be avoided.

In the engine valve operating system according to the second aspect of the present invention, the guide groove has a substantially circular cross section as viewed in the sliding direction of the tappet, and the main body has a partially cylindrical shape fitted into the guide groove. The shaft portion is a cylindrical shaft extending in a direction orthogonal to the main body portion, and is inserted into and supported by a hole provided in the tappet.

According to the second structure of the present invention, since the guide groove and the main body of the detent fitted and inserted in the guide groove have a substantially circular cross section and a partial cylinder, respectively, the contact area is large. , Sag of guide groove due to configuration 1 and abnormal wear,
Alternatively, it is possible to further enhance the effect of avoiding problems such as the rotation preventing member main body portion being caught in the guide groove.

According to the third aspect of the present invention, in the engine valve operating device, one tappet is provided with a plurality of types of cams having different cam nose shapes respectively corresponding to a plurality of tappet constituting members, and the tappet is provided on each cam. Correspondingly, the split tappet structure is divided into a plurality of surfaces by the surface extending in the sliding direction, and the valves are driven with different characteristics by engaging and disengaging the plurality of split tappets by the operation of the lock mechanism. .

According to the third aspect of the present invention, one tappet is provided with a plurality of types of cams having different cam nose shapes, and a plurality of divided tappets are provided corresponding to the plurality of types of cams. Since the plurality of split tappets are engaged and disengaged by the operation of the lock mechanism, the optimum valve opening / closing characteristics corresponding to the high speed rotation and the low speed rotation of the engine can be obtained, for example, fuel consumption, output, or exhaust gas. The characteristics can be dramatically improved.

In the valve operating system for an engine according to the fourth aspect of the present invention, one tappet is provided with a center cam and two side cams having different center cam and cam nose shapes, and the tappet is provided on the cam shaft corresponding to each cam. The tappet extending in the orthogonal direction has a substantially rectangular center tappet and side tappets on both sides thereof when viewed from the axis, and the rotation preventing member is attached to and supported by one side tappet, and the camshaft It is attached at a position offset in the circumferential direction by a predetermined angle with respect to the direction.

According to the fourth aspect of the present invention, the tappet has a substantially rectangular center tappet corresponding to the center cam and side tappets corresponding to two side cams having different cam nose shapes. Since the anti-rotation member is provided and its position is a position offset in the circumferential direction by a predetermined angle with respect to the cam shaft direction,
The size and weight of the engine can be reduced. Specifically, in the case of an engine cylinder head having two or more intake valves and two exhaust valves for each cylinder, the tappet guide hole wall sandwiched between adjacent tappet guide holes is thin,
It is difficult to form the guide groove, but by providing the guide groove and the detent member at a position offset by a predetermined angle in the circumferential direction with respect to the cam axis direction, it becomes easy to form the guide groove and the engine cylinder The length of the head in the cam axis direction can be shortened, and as a result, the size and weight can be reduced.

Further, if the guide groove is forcibly formed in the thin wall of the tappet guide hole, the excess thickness is reduced and the cylinder head is easily deformed. As a result, the rotation preventing member is smoothly moved in the guide groove. There is a possibility that it will not be able to slide, and this is avoided by providing it at a position offset in the circumferential direction by a predetermined angle with respect to the cam axis direction, and reliability is improved.

In the valve operating system for an engine according to the fifth aspect of the present invention, one tappet is provided with a center cam and two side cams having different center cam and cam nose shapes, and the tappet is provided on the cam shaft corresponding to each cam. A tappet that extends in a direction orthogonal to each other has a substantially rectangular center tappet and side tappets on both sides thereof as viewed in the axial direction, and a lock mechanism that extends in the cam axial direction is configured so that both tappets can be engaged and disengaged. The member is attached to and supported by a bush attached to a lock mechanism hole formed in one side tappet.

According to the fifth aspect of the present invention, in addition to the effect described in the third aspect, the rotation preventing member is attached and supported by the bush attached to the lock mechanism hole formed in the one side tappet. Therefore, it is not necessary to separately form a hole for supporting the anti-rotation member, and it is not necessary to newly provide another bush, so that the cost can be reduced.

In the engine valve operating system according to the sixth aspect of the present invention, when the cam side end surface of the main body of the detent member extends closer to the tappet upper surface than the shaft, and the valve is closed,
The upper surface of the cam side end surface serves as a tappet height position measurement reference surface.

According to the sixth aspect of the present invention, since the cam side end surface of the main body portion of the anti-rotation member extends closer to the top surface of the tappet than the shaft, it rotates in the cam direction from the tappet guide hole. The main body of the stopper member can be in a protruding state, whereby the upper surface of the tappet, that is, the upper surface of the tappet with respect to the cam-side end surface upper surface of the main body of the rotation preventing member,
The height of the sliding contact surface of the tappet that makes sliding contact with the cam can be easily measured, the clearance between the sliding contact surface of the cam and the tappet is required without using a thickness gauge, and workability during engine assembly is enhanced.

[0020]

As described above, according to the present invention, in the tappet which constitutes the valve operating device of the engine, the detent member main body for restricting the rotation of the tappet in the circumferential direction accommodates the tappet. It is possible to prevent problems such as being caught in a guide groove provided on the guide and slidingly contacting the body of the detent member for the tappet, and to facilitate adjustment and measurement of the tappet clearance during engine assembly.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. First, the structure of the cam and tappet will be described with reference to FIG. 1 showing the valve operating system for the engine according to the present embodiment. In addition, in FIG. 1, (A) is a plan view of a sliding contact surface with a cam of a tappet, (B) is a front view thereof,
(C) is a side view.

The valve operating system according to the present embodiment includes a tappet guide hole 3 provided in a cylinder head 2 of an engine, a tappet 1 slidably accommodated in the tappet guide hole 3, a tappet 1, and a shim. It has a cam 4 provided to reciprocate the valve V in the axial direction of the tappet via the cam 5.

The cams 4 are provided for one tappet 1, three cams, that is, a center cam 4a that is in sliding contact with the substantially central portion of the tappet 1, and the center cam 4a so as to sandwich the center cam 4a. It has side cams 4b and 4c that are in sliding contact with the vicinity of both ends, and the cam nose height is set so that the center cam 4a and the side cams 4b and 4c have different lift amounts of the valve V. Specifically, the center cam 4a is a cam for high speed rotation of the engine, the side cams 4b, 4c are cams for low speed rotation of the engine, and the cam nose height of the center cam 4a is the side cam 4a.
It is set higher than the cam nose height of b and 4c.

The reason why a plurality of cams having different cam nose heights are provided in this way is to cope with low fuel consumption, high output, reduction of harmful exhaust gas, etc., and the center cam 4a or side cam 4b, The tappet 1 also has a divided structure so as to be in sliding contact with each of the 4c.

As can be seen from FIG. 1 (A), tappet 1
The sliding contact surface portion with the cam is divided into three parts, but as a configuration, it has a top plate sliding contact surface 1aa that slidably contacts the center cam 4a and has a substantially rectangular shape (both ends contact the end portions of the side tappets 1s). A center tappet 1a of a substantially I shape having a protrusion that slides and prevents the end portion of the side tappet from directly slidingly contacting the tappet guide hole 3 to prevent uneven wear. The side tappet 1s has top plate sliding contact surfaces 1bb and 1cc that are in sliding contact with the side cams 4b and 4c. That is, the tappet 1 includes a side tappet 1s which is formed by cutting a top plate portion having a predetermined width and a circumferential portion from the substantially ceiling plate cylindrical member over a predetermined height in the axial direction, and a part of the removed side tappet 1s. The shape is such that the center tappet 1a, which is a member having substantially the same shape as that deleted with the clearance of, is combined. In the following description, of the side tappets 1s, the side tappet on the side having the top plate sliding contact surface 1bb is referred to as the side tappet 1b, and the side tappet on the side having the top plate sliding contact surface 1cc is referred to as the side tappet 1c (Fig. 2).

Further, the center tappet 1a and the side tappets 1b, 1c are provided with a lock member operated by hydraulic pressure inside the tappet so that the center tappet 1a and the side tappets 1b, 1c can be engaged and disengaged, and an oil passage G for that purpose is provided in the cylinder head 2. It also extends toward tappet 1.

Further, the side tappet 1b is provided with a detent member main body portion 6 for restricting rotation of the tappet in the circumferential direction thereof so as to project from the circumference of the tappet 1. A guide groove 3a having a substantially circular cross section in the tappet sliding direction is provided in the tappet guide hole 3 of the cylinder head 2 so as to accommodate the main body portion 6 in the tappet sliding direction. In addition, detailed description will be added separately for the rotation preventing member and the guide groove 3a.

The outline of the valve gear according to the present embodiment has been described above. Next, based on FIG. 2 showing the details of the tappet,
The structure will be described. 2A is a plan view of the tappet according to the present invention, FIG. 2B is a cross-sectional view taken along line XX in FIG. 2A for showing the lock member and the rotation-stopping member main body, and FIG. 3 is a sectional view taken along line YY in FIG.

In FIG. 2 (A), as described above, the tappet 1 has a center tappet 1a and side tappets 1b and 1c positioned so as to sandwich the center tappet 1a. The detent member main body portion 6 is provided toward.

Next, the center tappet 1a and the side tappets 1b, 1c of the tappet 1 and the lock members, and the rotation preventing member main body will be described in detail. First, the lock member will be described. In FIG. 2B, the center tappet 1a has a cam axis at a position a predetermined distance from the top plate sliding contact surface 1aa and the top plate sliding contact surface 1aa.
A circular hole 8 is formed substantially parallel to the side tappet, and a coaxial circular hole 10 is also formed in the side tappet 1s from one side tappet 1b to the other side tappet 1c. Here, the circular hole 8 and the circular hole 10 have the same inner diameter, and
When the top plate sliding contact surface 1aa of the center tappet 1a and the top plate sliding contact surfaces 1bb, 1cc of the side tappets 1b, 1c are substantially at the same level, the circular hole 8 and the circular hole 10 are coaxial. There is.

The circular hole 8 provided in the center tappet 1a has a plunger 16, a sleeve A18, and a spring 2 therein.
0 and a sleeve B22 are inserted. The sleeve B22 is press-fitted into the circular hole 8 in the vicinity of the side tappet 1b side end of the circular hole 8 provided in the center tappet 1a,
An end of the plunger 16 on the side tappet 1b side is housed in the inner diameter portion thereof so as to be axially reciprocable. A spring 22 is provided on the inner end surface of the sleeve B22 (on the center side of the center tappet 1a), one end of which is in contact with the other end, and the other end is in contact with a flange (no reference numeral) provided on the outer periphery of the plunger 16. The sleeve A18 has a circular hole 8
Is press-fitted in the vicinity of the end on the side of the side tappet 1c, and the end of the plunger 16 on the side tappet 1c side is reciprocally housed in its inner diameter.
Further, the inner end (the center side of the center tappet 1a) end face is in contact with the flange of the plunger 16, so that the plunger 16 is urged by the spring 22.
It is restricted from protruding to the c side.

A bush 24 for receiving the plunger 16 is press-fitted into the circular hole 10 in the side tappet 1b. The center tappet 1a side of this bush 24 is
It has the same inner diameter as the sleeve B22 so as to receive the plunger 16 when the plunger 16 moves into the side tappet 1b to engage and lock the center tappet 1a and the side tappet 1b. On the other hand, bush 24
The outer diameter of the tappet on the outer peripheral side is smaller than the inner diameter on the center of the tappet, and the pin 26 is press-fitted.
A locking member body 6 is fitted in a loose state to prevent the tappet 1 from rotating in the circumferential direction. On the other hand, a substantially bottomed cylindrical seal member 14 is press-fitted into the circular hole 10 in the side tappet 1c, and a piston 12 is housed inside the seal member 14.

As described above, the locking member according to the present invention is the plunger 1 provided on the center tappet 1a.
6, the sleeve A18, the spring 20, the sleeve B22, and the bush 2 provided on the side tappet 1b.
4 and a piston 12 provided on the side tappet 1c,
The seal member 14 and the center tappet 1a and the side tappet 1b are controlled by the hydraulic pressure of the engine.
A locked state in which 1c is engaged and an unlocked state in which they are disengaged can be taken. This hydraulic oil is supplied from the oil passage G of the cylinder head 2 described earlier with reference to FIG. 1 to the oil passage R of the tappet 1 shown in FIG.
2 through the opening R2 provided between the side end portion of the seal member 14 and the piston 12 in the side tappet 1c of FIG. 2B to the hydraulic chamber PR.

FIG. 3 is a view for explaining a locked / unlocked state of the center tappet 1a and side tappets 1b, 1c in the tappet 1, which is unlocked when the engine of FIG. The locked state is (B)
It is during high-speed rotation of the engine. At the time of low speed rotation of (A), the oil pressure is set low, so that the piston 12 is prevented from moving toward the center tappet 1a even if oil is supplied from the opening R2 to the oil pressure chamber PR. Therefore, the plunger 1 provided on the center tappet 1a
6 does not move to the side tappet 1b side by the piston 12, and is restricted by the sleeve A18 in the direction of the side tappet 1c as well, so that it is stopped inside the center tappet 1a.

That is, in this state, since the plunger 16 is not engaged with the bush 24, the high speed cam 4a having a high cam nose height in the cam 4 is the center tappet 1a.
Although the center tappet 1a is pushed down while rotating in sliding contact with the center tappet 1a, two springs 30 having a small spring constant are provided at the lower part of the center tappet 1a, the lower surface of which is supported by a spring receiving member 32 (see FIG. )reference),
By the action of these springs 30, the center tappet 1a
The force for pushing down the valve (not shown) through the shim 5 is absorbed, and the high speed cam 4a does not contribute to the opening and closing of the valve. That is, in this unlocked state, the high speed cam 4a
The low speed cams 4b and 4c having a lower cam nose height act to push down the valve via the side tappets 1b and 1c.

Next, when the engine (B) is rotating at high speed, high-pressure oil is supplied to the hydraulic chamber PR from the opening R2 provided in the side tappet 1c. 12 is pushed out toward the center tappet 1a, and the piston 12 is spring 2
The urging force of 0 is overcome to push the plunger 16 toward the side tappet 1b to engage the bush 24.

In this state, the center tappet 1a is
Since the side tappets 1b and 1c are engaged and locked, the side tappets 1b and 1c are pushed down by a lift amount corresponding to the cam nose height of the high speed cam 4a, and the valve is also opened with the same lift amount. .

When the engine is rotated from the high speed rotation to the low speed rotation, the oil pressure decreases, and accordingly the piston 12
Loses the force to move the plunger 16 to the side tappet 1b side, the spring 20 returns the plunger 16 to a predetermined position regulated by the sleeve A18, and the side tappet 1b by the low speed cams 4b and 4c as described above,
It is possible to return to the opened / closed state of the valve via 1c.

Next, a description will be given of the detent member main body 6 which restricts the rotation of the tappet 1 in the circumferential direction. As described above with reference to FIG. 2, the rotation preventing member main body 6 is loosely fitted to the pin 26 press-fitted on the outer peripheral side of the tappet of the bush 24 provided on the side tappet 1b. In FIGS. 1 to 3 shown so far, the detent member main body 6 is projected in the same direction as the axis of the cam shaft, but as shown in FIG. If the structure is such that it is offset by an angle θ with respect to EE, and the guide groove 3a of the tappet guide hole 3 that accommodates this is also offset by an angle θ with respect to the axis E-E of the camshaft, Since it is possible to reduce the thickness of the wall between the tappet guide holes that are adjacent to each other in the axis E-E direction, it is useful for reducing the size and weight of the engine.

As shown in (1) of FIG. 5, the center tappet 1a has a structure in which the detent member main body 6 is offset with respect to the axis E--E of the camshaft by an angle θ. The central axis of the hole 8 provided and the holes 10 provided in the side tappets 1b, 1c are formed at an angle θ from the camshaft axis E-E, and a lock member (not shown) is provided therein, and the bush described above is provided. By fixing the pin 26 to 24, the detent member main body 6 is also arranged at a position offset by an angle θ with respect to the camshaft axis E-E, or
As shown in (2) of FIG. 5, the bush 24 does not have the pin 26 and the side tappet 1b (1c may be used).
Various embodiments can be taken, such as a structure in which the pin 26 is integrally fixed to the outer peripheral wall of the cam shaft axis E-E at an angle θ and the rotation preventing member main body portion 6 is fitted to the pin 26.

Next, the relationship between the detent member main body 6 and the guide groove 3a which houses the detent member 6 and restricts the tappet 1 from rotating in the circumferential direction thereof will be described in detail with reference to FIG. explain. In FIG. 6, (A) is a perspective view showing a state in which the detent member main body 6 is housed in the guide groove 3a having a substantially circular cross section. As you can see,
The anti-rotation member body 6 has a sliding contact surface 6s that is in a slightly vertically long substantially cylindrical shape and is in sliding contact with the guide groove 3a along the guide groove 3a provided on the peripheral wall of the tappet guide hole 3. A pin hole 6a into which the pin 26 is inserted is formed at a portion slightly below the longitudinal center at a right angle to the tappet sliding direction. The end of the pin 26 toward the center of the tappet is press-fitted and fixed to the bush 24 as described with reference to FIG. 2, and the shaft of the pin 26 has the shaft of the tappet sliding contact surface 1.
It is provided at a position of a predetermined size from aa and 1bb.

FIG. 6B1 is a sectional view taken along line FF in FIG. 6A, and as shown in FIG. 6B, the inner diameter of the pin hole 6a is slightly larger than the outer diameter of the pin 26. Therefore, the pin 26 is inserted in the pin hole 6a in a loose state. This is because the detent member main body portion 6 causes the swing in the guide groove 3a as shown by the arrow with the axis Z-Z of the pin 26 as the substantial center. That is, the detent member main body 6 reciprocates in the guide groove 3a while slightly swinging about the axis ZZ of the pin 26. As a result, the guide groove 3a comes into contact with the sliding contact surface 6s of the anti-rotation member main body 6 in a large area, and the guide groove 3a locally dents, or finally causes abnormal wear or seizure, or the anti-rotation member. Guide groove 3 of body 6
It is possible to avoid biting into a.

As another embodiment in which the detent member body 6 swings as described above, although not particularly shown, the detent member body 6 and the pin 26 are integrally formed, and the pin 2
The end of the tappet 6 on the center side may be inserted into the bush 24 in a loose state instead of being press-fitted. That is, in this case, the inner diameter of the hole for receiving the pin 26 of the bush 24 is formed to be larger than the outer diameter of the pin 26, so that the detent member main body portion 6 is integrated with the pin 26.
It reciprocates in the guide groove 3a while swinging about the axis of.

Further, as shown in FIGS. 1 to 3 described so far in the present embodiment, the cam side end surface of the anti-rotation member main body 6 has the top plate sliding contact surface of the tappet 1 slidingly contacting the cam 4. It is arranged at a position close to 1aa, 1bb, and 1cc.
In detail, as shown in FIG. 7, a valve (not shown)
When the tappet 1 is closed and the tappet 1 is at the uppermost position, the cam side end surface H2 of the anti-rotation member main body 6 can be projected to the cam side from the upper end surface of the tappet guide hole 3 by, for example, about several mm. Therefore, the structure is obviously different from that of FIG. 8 shown as the prior art,
A new effect as described below can be obtained.

According to such a structure, since the cam is a component that has been conventionally ground with high precision, the cam shaft axis line height position, which is predetermined, is used as a reference, and the reference is set at a position of a predetermined distance L1. A surface H1 (in FIG. 7, the cylinder head 2 is processed to provide the reference surface H1) is defined. If the height dimension L2 between the reference surface H1 and the cam side end surface H2 of the rotation preventing member main body 6 is measured,
Since the shaft center of the pin 26 is set with high accuracy from the tappet sliding surfaces 1aa, 1bb to a predetermined position,
The height position of the tappet in the valve closed state can be accurately determined. In other words, the tappet clearance, which is the distance between the valve and the tappet sliding contact surface in the valve closed state, is measured by measuring the height of the cylinder head H1 with respect to the cam-side end surface H2 of the anti-rotation member body 6. Since it is possible to measure and manage, the thickness gauges of the conventional cam 4 and the toppet sliding contact surfaces 1aa and 1b of the tappet 1 can be measured.
The work of inserting the gap between b and 1 cc to measure the tappet clearance becomes unnecessary, and the workability can be dramatically improved.

As a structure for further drawing out the effect, as shown in FIG. 6 (B2), the cam side end surface of the rotation stopping member main body 6 is formed in an arc shape having a radius R from the center of the pin hole 6a. Good. According to this, even when the anti-rotation member main body portion 6 projects from the tappet guide 3 at an angle swung with respect to the center line KK of the guide groove 3a, the reference height position of the cam side end surface H1. Can be kept constant and the tappet clearance adjustment and management accuracy can be improved.

As described above, according to the present invention, one tappet is divided into a plurality of divided tappets, and a lock mechanism for locking and unlocking the plurality of tappets is provided therein and a plurality of cam nose heights are provided. A valve operating device for an engine, in which a valve lift characteristic is variable by using a cam having a certain height, wherein a detent member that restricts rotation of a tappet in a circumferential direction is offset from an axial direction of a camshaft. Downsizing is possible,
Further, durability can be improved by making the detent member swingable in the tappet sliding direction within the guide groove provided in the tappet guide hole. Further, by disposing the cam side end surface of the rotation preventing member at a position close to the sliding contact surface with the cam of the tappet, the tappet clearance can be easily measured and managed, and the workability can be improved.

[Brief description of drawings]

FIG. 1 is a schematic view of a valve gear according to the present invention.

FIG. 2 is a detailed view of the valve gear according to the present invention.

FIG. 3 is a view showing a lock mechanism of a split tappet.

FIG. 4 is a diagram showing an offset position of a rotation preventing member.

FIG. 5 is a diagram showing details of a rotation stopping member.

FIG. 6 is a diagram showing swing of a rotation preventing member.

FIG. 7 is a diagram illustrating a height position reference of a tappet.

FIG. 8 is a diagram showing a conventional technique.

[Explanation of symbols]

1 ... Tappet 1a ... centre tappet 1b, 1c, 1s ... Side tappet 2 ... Cylinder head 3 ... Tappet guide hole 3a ... Guide groove 4 ... cam 4a ... Center cam 4b, 4c ... Side cam 6 ... Non-rotating member body 12 ... Piston (lock mechanism) 16 ... Plunger (lock mechanism) 24 ... Bush (lock mechanism) 26 ... pin H3: Tappet height position reference surface of the rotation prevention member body

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takashi Inoi             3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda             Within the corporation (72) Inventor Taketoshi Yamauchi             3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda             Within the corporation F-term (reference) 3G016 AA06 AA19 BA19 BA34 BA36                       BB05 BB06 BB07 CA02 CA04                       CA11 CA12 CA21 CA22 CA27                       CA29 CA33 CA52 DA09 DA12                       FA37 FA38 FA39 GA01 GA02                 3G018 AB07 AB16 BA03 BA09 BA24                       BA36 DA03 DA17 DA18 DA24                       DA28 DA85 DA86 FA06 GA02                       GA17 GA18

Claims (6)

[Claims] A tappet having an outer shape of a substantially cylindrical shape is formed of a plurality of tappet constituent members, and an engine having a lock mechanism for engaging and disengaging the tappet constituent members and a variable mechanism for changing valve lift characteristics. In the valve operating device, a tappet guide hole having a guide groove extending in the sliding direction of the tappet and accommodating the tappet is formed in a cylinder head, and the tappet is provided in the guide groove so that the tappet is circumferentially arranged. A detent member that restricts rotation of the body is inserted into the detent member, and the detent member includes a main body portion having a sliding contact surface that is inserted into the guide groove and extends in the sliding direction; A valve operating device for an engine, comprising a shaft portion supported by a tappet, and the main body portion capable of swinging about an axis of the shaft portion. 2. The guide groove has a substantially circular cross section when viewed in the tappet sliding direction, the main body portion is a partial cylindrical shape fitted into the guide groove, and the shaft portion is
The valve operating device for an engine according to claim 1, wherein the valve operating device has a columnar shaft extending in a direction orthogonal to the main body, and is inserted into and supported by a hole provided in the tappet. 3. A plurality of cams having different cam nose shapes respectively corresponding to the plurality of tappet constituting members are provided for one tappet, and the tappets have a plurality of surfaces extending in the sliding direction corresponding to the respective cams. The valve operating system for an engine according to claim 2, wherein the valve is driven with different characteristics by having a split tappet structure divided into two, and a plurality of split tappets are disengaged by the operation of the lock mechanism. 4. A tappet is provided with a center cam and two side cams different in cam nose shape from the center cam, and the tappet extends in a direction orthogonal to the cam axis in a substantially rectangular shape corresponding to each cam. Of the center tappet and side tappets on both sides thereof, and the detent member is configured to be supported by being attached to one of the side tappets and at a position offset in the circumferential direction by a predetermined angle with respect to the cam axis direction. A valve operating system for an engine according to claim 3, which is mounted on a valve. 5. A tappet is provided with a center cam and two side cams having different cam nose shapes from the center cam, and the tappet extends in a direction orthogonal to the cam shaft in a substantially rectangular shape corresponding to each cam. The center tappet and the side tappets on both sides thereof are configured so that both tappets can be engaged and disengaged by the lock mechanism extending in the cam axis direction, and the detent member is formed on one side tappet. The engine valve operating system according to claim 3, wherein the valve operating device is mounted and supported by a bush mounted in the lock mechanism hole. 6. The cam-side end surface of the main body of the detent member extends closer to the upper surface of the tappet than the shaft, and when the valve is closed, the upper surface of the cam-side end surface is at the tappet height position. The engine valve operating system according to claim 2, which is used as a measurement reference plane.