JPH07139315A - Valve system of engine - Google Patents

Abstract

PURPOSE:To eliminate rattling by arranging a rotary member in the inside of a tappet body on which a cam is abutted, and arranging therebetween an energizing member for relatively turning the rotary member, and also by screwing a slide member into the rotary member so that it is abutted on the valve stem. CONSTITUTION:When a clearance is caused between a cam 24 and a tappet body 28, the tappet 26 extends in the axial direction of a valve stem 22 against the energizing force of a torsion spring 34, so that the clearance is automatically eliminated. At that time, the torsion spring 34 is extended between the tappet body 28 and a rotary member 30, and the rotary member 30 is turned by this energizing force with regard to the tappet body 28. Thereby, a slide member 32 screwed into the rotary member 30 moves in the axial direction of the valve stem 22 while its rotation is restricted by a guide member 40. As a result, the tappet 26 extends and the zero-lash adjustment function can be fulfilled. On the other hand, the closed space formed by the tappet body 28, the slide member 32, and the guide member 40 is utilized as a lubricating chamber 42.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve operating mechanism for driving a valve to open and close an intake hole or an exhaust hole provided in a combustion chamber of an engine, and more particularly, to a rotary operation of a cam in a valve stem. It is related to the valve mechanism of the engine which improved the tappet to transmit.

[0002]

2. Description of the Related Art Generally, in a valve mechanism for an engine of an automobile or the like, there is a cam between a cam which is driven to rotate by a crankshaft and a valve which opens and closes an intake hole and an exhaust hole of a combustion chamber. A tappet is provided that converts rotational movement into linear movement and transmits it to the valve stem. In such a valve operating mechanism, wear progresses between the cam that is rotationally driven at high speed and the tappet with which it abuts due to changes over time due to continuous sliding contact, and as a result, the cam and tappet move. There was a problem that a considerable clearance was generated between the two. Due to this clearance, the lift amount according to the cam profile was not accurately transmitted to the tappet, and therefore the valve could not be operated at an appropriate timing and with an appropriate lift amount.

Therefore, in order to solve the above problem, research has been conducted on a mechanism for automatically extending the tappet itself, which causes a clearance between itself and the cam due to wear, in order to cancel the wear amount. A hydraulic tappet has become the mainstream of such a mechanism in recent years, and the hydraulic tappet is adapted to expand and contract by the action of supplying and discharging hydraulic pressure, and is actually put into practical use. At present, a method of mechanically solving the problem is being studied in parallel with the hydraulic system, and the proposal of Japanese Patent Laid-Open No. 5-10109 shown in FIG. 5 is one example.

An insertion hole 2a is formed in the cylinder head 2 of the engine, and a tappet 8 is vertically slidably provided in the insertion hole 2a. A cam 4 arranged above the tappet 8 is in contact with the upper surface of the tappet 8, and an upper end 6a of a valve stem 6 arranged below is in contact with the lower part of the tappet 8. ing. Then, the tappet 8 slides up and down in the insertion hole 2a by the rotationally driven cam 4, whereby the valve stem 6 moves up and down along its axial direction to open and close a valve (not shown).

The tappet 8 arranged between the cam 4 and the valve stem 6 will be described in more detail. The tappet 8 has a mechanism for eliminating the above-mentioned clearance, and this mechanism is mainly used for the tappet 8. The tappet body 10, which is a main component, a rotary member 12, a slide member 14, and a torsion spring 18 are included. Each member will be described in detail. The tappet body 10 is formed into a hollow cylindrical body having an upper end closed and an open lower end, the upper end surface 10a of which is slidably contacted with the cam 4, and the outer peripheral side surface of the tappet main body 10 having the insertion hole 2a. Is in sliding contact with the inner surface of the. Further, a ring-shaped guide portion 10c is formed so as to hang down from the ceiling surface 10b of the hollow cylindrical cylindrical tappet body 10 which is the back side of the upper end surface 10a. Inside the guide portion 10c, there is provided a hollow cylindrical rotating member 12 whose upper end is closed and whose lower end is open. The top of this rotating member 12 is slidably contacted with the ceiling surface 10b. A male screw is threaded on the entire outer peripheral surface of the rotary member 12 along its axial direction. On the other hand, inside the guide portion 10c of the tappet body 10, a hollow cylindrical slide member 14 is provided outside the rotary member 12 so as to cover the rotary member 12. This slide member 14 is
The upper end is opened so that the rotating member 12 can be inserted,
In addition, the lower end is formed so as to close the lower end of the rotating member 12, and further, on the inner peripheral surface of the slide member 14,
A female screw that is screwed into the male screw of the rotating member 12 is threaded. In particular, this slide member 14 is attached to the guide portion 10c,
It is mounted so as to be slidable in the vertical direction along with this rotation being stopped. A torsion spring 18 is provided in the internal space 16 defined by both the rotating member 12 and the slide member 14 assembled in this manner.
The torsion spring 18 has one end fixed to the slide member 14 and the other end fixed to the rotating member 12,
The rotating member 12 is biased in a direction of rotating the sliding member 14. The lower end surface 14a of the slide member 14 is adapted to contact the valve stem 6 inserted from the lower end of the tappet body 10.

With the above construction, when the cam 4 and the tappet body 10 are in contact with each other and there is no clearance therebetween, the tappet 8 sandwiched between the cam 4 and the valve stem 6 from above and below looks like a rigid body. The rotational driving force of the cam 4 is transmitted to the valve stem 6. On the other hand, when a clearance is generated between the cam 4 and the tappet body 10, a moment when the pressing force from the cam 4 disappears or becomes extremely small occurs, and at this time, the torsion spring 18 between the rotating member 12 and the slide member 14 is generated. Will be extended. By this extension action, the rotating member 12 rotates with respect to the slide member 14 which is prevented from rotating, and this rotation proceeds in the direction of loosening the screwing of the slide member 14 and the rotating member 12, so that the upper end of the ceiling of the tappet body 10 is closed. Rotation member 1 whose position is regulated on the surface 10b
The slide member 14 moves downward with respect to 2. As a result, the length of the tappet 8 as a whole is extended, and the clearance generated between the cam 4 and the valve stem 6 can be eliminated.

[0007]

By the way, the tappet 8
As described above, the opening / closing operation of the intake hole or the exhaust hole is performed at an extremely high speed, and therefore, it is repeatedly repeatedly moved up and down in the insertion hole 2a. In the tappet 8 in such an operating state, in order to cancel the clearance, the rotating member 12 and the sliding member 14 are frequently rotated or slid. Here, in the above-mentioned conventional tappet 8, as described below, there is a portion that causes rattling due to the assembly structure. Specifically, in the assembling structure of the rotating member 12 that houses the torsion spring 18 and the slide member 14, the backlash and torsion spring 18 existing in these screwing portions A on which the biasing force of the torsion spring 18 acts A gap between the biased slide member 14 and the guide portion 10c and a contact portion between the rotary member 12 biased by the torsion spring 18 and the ceiling surface 10b of the tappet body 10 are the torsion spring 18 and the torsion spring 18.
There is a problem in that the elasticity of the rubber tends to cause rattling. That is, in the conventional structure, since the torsion spring 18 is arranged between the rotating and sliding parts, the torsion spring 18 is easily affected by the rotating and sliding operation, and as a result, on the contrary, The elastic effect of the torsion spring 18 appears between the rotary member 12 and the slide member 14 which are in an assembly relation with the torsion spring 18, and between them and the surrounding structure, which easily causes rattling, which causes abnormal noise. In addition, there is a problem of durability due to early wear, and there is a problem that it is difficult to secure the zero lash adjuster function of the tappet 8 for a long period of time.

The present invention has been made in view of the above circumstances, and an object thereof is to make it possible to exert a zero-lash adjuster function comparable to the conventional one and to eliminate rattling in the assembly structure. Another object of the present invention is to provide an engine valve operating mechanism that can prevent abnormal noise and improve durability by reducing wear.

[0009]

In order to achieve the above object, in the present invention, in order to eliminate the clearance between the cam and the shaft end of the valve stem, the cam is interposed therebetween, and the biasing means biases the biasing means. In a valve operating mechanism of an engine having a tappet that expands and contracts in the axial direction of the valve stem in accordance with the above, a rotary member rotatably provided around the axis of the valve stem in a tappet body that is in contact with the cam. An urging means disposed between the rotating member and the tappet body for urging the rotating member to rotate relative to the tappet body, and the rotation of the tappet body being regulated by the tappet body. And a slide member that is slidably supported in the axial direction of the valve stem, is screwed into the rotating member, and abuts on the axial end of the valve stem.

Further, the rotating member is formed in a hollow cylindrical shape along the axial direction of the valve stem, having an opening portion at the cam side end portion which is closed by the tappet body.
The urging means is disposed inside the rotating member, and on the other hand,
The slide member is formed in a hollow cylindrical shape along the axial direction of the valve stem so as to be screwed into the rotary member from the outside, and the tappet body is surrounded by the slide member to regulate its rotation. A guide member for guiding the slide movement is provided.

Further, the tappet body is characterized in that a regulating portion is formed on the slide member in order to regulate the sliding amount of the slide member, the regulating portion facing each other in the sliding direction.

A lubricating oil chamber is defined by the tappet main body, a guide member provided on the tappet main body for guiding the slide member, and the slide member screwed to the rotating member. And

Further, the rotating member is formed with an engaging portion for rotating the rotating member relative to the tappet body against the urging means at a position of an axis of rotation thereof. .

[0014]

The operation of the present invention relating to the above-described structure will be described. When there is no clearance between the cam and the tappet body, the tappet is sandwiched between the cam and the valve stem without any clearance, and the cam is rotationally driven as a rigid body. Transfers force to the valve stem. On the other hand, when a clearance is generated between the cam and the tappet body, the tappet expands along the axial direction of the valve stem in response to the urging of the urging means and automatically cancels the clearance. Explaining the extension action of the tappet, since the pressing force of the cam on the tappet body disappears or becomes small due to the clearance, the biasing means can extend between the tappet body and the rotating member. The rotating member rotates with respect to the tappet body which is a fixed system due to the bias. By the rotating operation of the rotating member, the slide member screwed with the rotating member is slid in the axial direction of the valve stem in combination with the rotation restriction by the tappet body.
Then, this movement of the slide member toward the valve stem side with respect to the rotary member that occurs between the cam and the valve stem results in the expansion of the tappet.

In particular, according to the present invention, the biasing means for expanding and contracting the tappet in the assembling structure is a tappet body that does not rotate or slide when the tappet expands or contracts, and a rotating member that only rotates with respect to the tappet body. Since it is arranged between the rotary member and the slide member as in the conventional structure, at least between the rotary member and the slide member and between the slide member and the slide member. The elasticity of the urging means does not appear between the tappet body and the tappet body, and thus rattling does not occur in these portions, so that abnormal noise can be prevented and durability can be improved. Further, as for the mutual relationship between the tappet body and the rotating member in which the biasing means is interposed, at least one tappet body constitutes a fixed system relative to the rotating member, and therefore, as in the conventional case, Unlike the assembling relationship in which the biasing means is provided between the sliding member and the rotating member that also operate, rattling can be further suppressed.

Further, since the tappet body is provided with the regulating portion for regulating the sliding amount of the slide member, the slide member, which is relatively moved in the direction in which the tappet is extended with respect to the rotating member with respect to the rotating member, increases with the increase in the clearance. It can be prevented that the screwed state cannot be maintained and is dropped.

Further, the main constituent parts of the tappet,
A tappet body that forms the outer shell of the tappet and is in contact with the cam; and a slide member that is in contact with the shaft end of the valve stem,
Since a closed space formed by the guide member surrounding the slide member and the slide member and the tappet body is formed as a lubricating oil chamber, it is not necessary to separately provide a component that constitutes the lubrication system, and a simple configuration is provided. Can be

Furthermore, at the rotational axis position of the rotary member,
Since the engaging portion for rotating the rotating member relative to the tappet body is formed, the urging member is urged through the engaging portion when the urging means is provided between the rotating member and the tappet body. The rotating member can be rotated against the means, and the initial setting of the biasing force of the biasing means can be freely performed from outside the tappet body.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The engine has a combustion chamber that burns fuel such as gasoline, and an intake hole and an exhaust hole are formed above the combustion chamber to suck the air-fuel mixture and discharge the exhaust gas. It is a valve that opens and closes the intake / exhaust holes, and this valve is operated by a rotationally driven cam in accordance with the intake / exhaust timing. Figure 1
FIG. 4 is a vertical cross-sectional view showing a valve mechanism arranged between a cam 24 and a valve stem 22 above a valve. A cylinder head 20 that constitutes an engine is formed with a through hole 20a in a substantially vertical direction. A valve stem 22 is provided below the through hole 20a and a cam 24 is provided above the through hole 20a. A tappet 26 is interposed between the cam 24 and the cam 24 so as to be sandwiched therebetween. As is conventional, the valve stem 22 is provided with a valve spring 23 surrounding the valve stem 22 in the axial direction between the retainer 21 fitted to the upper shaft end 22a of the valve stem 22 and a cylinder head wall (not shown). The valve spring 23 is provided so as to elastically bias the valve stem 22 upward in order to maintain the valve closed state. Further, the cam 24 is also attached to the outer periphery of the cam shaft 25 with a predetermined profile as in the conventional case,
It is adapted to be rotationally driven by the rotational driving force transmitted from the crankshaft.

On the other hand, the tappet 26 is formed in the shape of a hollow cylinder whose upper end 26a is closed and whose lower end is open, and is interposed between the cam 24 and the valve stem 22. A peripheral surface 24a of the cam 24 is brought into contact with the upper end 26a of the tappet 26 to receive a pressing force from the cam 24. Further, an upper shaft end 22 a of a valve stem 22 including a retainer 21 is inserted into the open lower end of the tappet 26. Further, in particular, the tappet 26 of the present embodiment is provided with a mechanism for canceling the above-mentioned clearance. This mechanism mainly constitutes the main body of the tappet 26, and the tappet main body 28 that is in contact with the cam 24 and the tappet main body. A rotating member 30 provided rotatably around the axis of the valve stem 22 in 28, and arranged between the rotating member 30 and the tappet body 28, for rotating the rotating member 30 relative to the tappet body 28. A torsion spring 34 as an urging means for urging, and a tappet body 28, the rotation of which is restricted, is slidably supported in the axial direction of the valve stem 22 and screwed to a rotating member 30. Edge 2
2a and the slide member 32 which contact | abuts.

Each member will be described in detail below.
The tappet body 28 is a hollow cylindrical body having an upper end 26a closed and an open lower end, and the upper end 26a with which the cam 24 is slidably contacted is formed flat and smooth. Further, the tappet body 28 is inserted into a through hole 20a formed in the cylinder head 20, and an outer peripheral side surface 28a of the tappet main body 28 is formed into a flat and smooth curved surface in close contact with the inner peripheral surface of the through hole 20a. It is designed to smoothly slide inside. Further, at the lower end and the upper end of the tappet body 28, the peripheral edge portions thereof are chamfered inward, so that the tappet body 28 can be moved quickly and smoothly without being obstructed from sliding in the vertical direction. ing.

In the hollow inside of the tappet body 28, a circular ring-shaped mounting portion 36 centering on the axial center of the valve stem 22 is formed so as to hang down from the ceiling surface which is the back side of the upper end 26a. Has been done. Inside the mounting portion 36, a ring-shaped wear-resistant member 3 covering the ceiling surface of the tappet body 28 and the inner peripheral surface of the mounting portion 36 to cover them.
8 is fitted. The wear resistant member 38 is provided so as to be interposed between the rotating member 30 and the tappet body 28, which will be described later, and is formed to have an appropriate size within a range in which the rotating member 30 and the tappet body 28 do not come into direct contact with each other. To be done. Specifically, the wear-resistant member 38 is formed in a ring shape along the inner peripheral surface of the mounting portion 36, and a ring-shaped collar portion is protruded inward from the upper end portion thereof, and is formed in the center. The part is open.

A rotary member 30 is rotatably provided around the axis of the valve stem 22 inside the mounting portion 36 of the tappet body 28 to which the wear resistant member 38 is mounted. The rotating member 30 is formed into a hollow cylindrical body having an opening closed at the ceiling of the tappet body 28 at the upper end, which is the end on the cam 24 side, and a closed bottom at the upper end. Abrasion resistant member 3 on the side surface and the peripheral edge of the upper end
8 is slidably contacted with the tappet main body 28 so as not to come into direct contact with the tappet main body 28. The rotary member 30 is slidably contacted with the wear resistant member 38 to ensure wear resistance regardless of the material of the tappet body 28, and the durability of the assembled portion is improved.

On the outer peripheral surface of the rotary member 30, a male screw is formed in a portion lower than the range in which the rotary member 30 is in sliding contact with the wear resistant member 38 along its axial direction, that is, along the axial direction of the valve stem 22. Has been done.

On the other hand, a torsion spring 34 is provided in the space defined by the tappet main body 28 and the hollow rotating member 30 assembled with the ceiling portion of the tappet main body 28 closed at its upper end. To be This torsion spring 3
4, one end of which is engaged with a cutout portion 28b formed on the ceiling surface of the tappet body 28, and the other end of which is the rotating member 3
The tappet body 2 is engaged with a notch portion 30a formed on the bottom surface of 0 to be assembled between the tappet body 28 and the rotating member 30 so as to generate an elastic urging force in a torsional rotation direction.
The rotating member 30 is rotated relative to the rotating member 8. Therefore, the male screw is rotated by the rotation of the rotary member 30 due to the elastic force of the torsion spring 34.

A slide member 32 is provided so as to cover the rotating member 30 having the above-described structure and housing the torsion spring 34 from the lower outside. Like the rotating member 30, the slide member 32 is formed into a hollow cylindrical body having an open upper end and a closed lower end, and is disposed inside the tappet body 28. The upper shaft end 22a of the valve stem 22 inserted from the lower side of the tappet body 28 is in contact with the bottom surface of the slide member 32. Also, this slide member 32
A female screw that is screwed into the male screw of the rotating member 30 is formed on the inner peripheral surface of the. Further, the outer peripheral surface of the slide member 32 is surrounded by a guide member 40 described later. As will be described in detail, as shown in FIGS. 1 and 2, in the hollow inside of the tappet body 28, the guide member 40 is extended from the inner peripheral surface thereof toward the slide member 32 positioned radially inward.
Is provided. This guide member 40 is a slide member 3
The flange portion 40a that horizontally extends from the inner peripheral surface of the tappet body 28 toward the slide member 32 in correspondence with the mounting position of 2, and the inner peripheral edge of the flange portion 40a along the axial direction of the valve stem 22. And a sleeve 40b having a considerable length formed therein, and an inner peripheral surface of the sleeve 40b is slidably contacted with an outer peripheral surface of the slide member 32. In particular, the sleeve 40b is formed in a polygonal shape having an inner peripheral surface having a corner portion, and the outer peripheral surface of the slide member 32 surrounded by the sleeve 40b is also formed in a similar polygonal shape. By this, the rotation of the slide member 32 is restricted. Therefore, when the rotating member 30 rotates in the direction of releasing the elastic urging force of the torsion spring 34, the slide member 32 tries to rotate together with the male screw of the rotating member 30 via the female screw which is in sliding contact with the male screw of the rotating member 30. Three
Since the accompanying rotation of 2 is restricted by the guide member 40, the slide member 32 is slid with respect to the rotating member 30 while being guided by the guide member 40 in the direction in which the screw loosens. As a result, the slide member 32 is pushed downward to extend the distance from the upper end of the tappet body 28 to the bottom surface of the slide member 32. At this time, the bottom surface of the slide member 32 is in contact with the upper shaft end 22a of the valve stem 22 and its downward movement is restricted, so that the entire tappet 26 is moved upward. In this way, the tappet body 2 in which the guide member 40 for guiding the movement of the slide member 32 is formed
8 is formed to be thicker than the other portions at the location where it is attached to the guide member 40, so that the strength at that location is improved.

On the other hand, on the upper edge of the slide member 32,
From this, a flange-like abutting portion 3 that projects radially outward is provided.
2a is formed, and this abutting portion 32a serves as a restricting portion that surrounds the lower end surface of the mounting portion 36 that surrounds the rotating member 30 from the outside above it and the slide member 32 below from the outside. Between the upper end surface of the sleeve 40b of the guide member 40 and both of them are positioned so as to face in the sliding direction. The contact portion 32a is provided on the slide member 3
The slide member 3 is moved along with the vertical slide movement of 2.
When the slide member 32 is moved upward, it abuts the lower end surface of the mounting portion 36 to regulate its upward slide amount, and when the slide member 32 is moved downward, it abuts the regulating portion to regulate its downward slide amount. To function. As a result, when the slide member 32 moves downward and the screw loosens in order to release the elastic biasing force of the torsion spring 34, the slide member 32 moves downward more than necessary and falls off from the rotating member 30. Can be prevented. Further, when the slide member 32 is screwed into the rotary member 30 during assembly, it is possible to prevent the slide member 32 from being screwed too much and the rotary member 30 and the slide member 32 from being caught.

Further, the rotary member 30 has a hexagonal hole 30 as an engaging portion at the rotational axis position along the axial direction thereof.
b is formed. Specifically, the hexagonal hole 30b is formed on the bottom surface of the rotating member 30 so as to correspond to a hexagonal wrench which is a work tool. In addition, on the upper surface of the tappet body 28,
A service hole 28c coaxial with the hexagonal hole 30b and larger than this is formed. With this configuration,
A torsion spring 34 is provided between the rotating member 30 and the tappet body 28.
With the rotating member 30 inside the tappet body 28 through the service hole 28c.
The rotary member 30 can be rotated by inserting a hexagonal wrench into the hexagonal hole 30b. As a result, the rotating member 30 can be rotated relative to the tappet body 28 against the biasing force of the torsion spring 34, whereby the outer slide member 32 is slid upward and the tappet 26 is initialized. It can be done freely from outside 26.

Further, the tappet 26 has a tappet main body 28 constituting its outer shell, a guide member 40 provided so as to surround the slide member 32 from the inner peripheral surface of the tappet main body 28, and the guide member 40. The closed bottomed cylindrical slide member 32 forms a closed space surrounding the torsion spring 34, the rotation member 30, and the wear resistant member 38 above the slide member 32, and the closed space is configured as a lubricating oil chamber 42. To be done. That is, the hole 28d that connects the oil passage 20b formed in the cylinder head 20 and the closed space is formed in series between the cylinder head 20 and the tappet body 28, and the lubricating oil from the oil passage 20b is formed. The hole 2
The oil is supplied to the lubricating oil chamber 42 via 8d. As a result, the screw part and other peripheral parts can be lubricated. A discharge port 32b for discharging the supplied lubricating oil is formed at the bottom of the slide member 32. Further, a recess 28e formed on the outer side of the tappet body 28 and communicating with the hole 28d is formed in a vertically long shape corresponding to the vertical movement stroke amount of the tappet 26.

Next, the operation of this embodiment will be described. First, the operating state of the tappet 26 of this embodiment will be briefly described with reference to FIGS. 3 and 4. When there is no clearance between the cam 24 and the tappet body 28, the tappet 26 is sandwiched between the cam 24 and the valve stem 22 without any clearance, and serves as a rigid body to apply the rotational driving force of the cam 24 to the valve stem 22.
Have been communicated to. On the other hand, when a clearance is generated between the cam 24 and the tappet body 28, the tappet 26 extends along the axial direction of the valve stem 22 in accordance with the elastic biasing force of the torsion spring 34 and automatically cancels the clearance. Becomes The extension action of the tappet 26 will be described. Since the pressing force of the cam 24 against the tappet body 28 disappears or becomes small due to the clearance, the torsion spring 34 includes the tappet body 28 and the rotating member 30.
And the rotating member 30 is rotated with respect to the tappet body 28 by the urging force. By the rotating operation of the rotating member 30, the slide member 32 screwed with the rotating member 30 is slid in the axial direction of the valve stem 22 in cooperation with the rotation restriction by the guide member 40. This movement of the slide member 32 to the valve stem 22 side with respect to the rotating member 30 that occurs between the cam 24 and the valve stem 22 results in the tappet 26.
Will be extended, and the same zero lash adjuster function as before will be demonstrated.

By the way, especially in the present embodiment, the torsion spring 34 for expanding and contracting the tappet 26 due to the assembly structure.
Is disposed between the tappet body 28 that neither rotates nor slides when the tappet 26 expands or contracts, and the rotating member 30 that only rotates with respect to the tappet body 28. Compared to the case where the urging means is provided between the rotary member 30 and the slide member 32, and between the slide member 32 and the tappet body 28, the elasticity of the torsion spring 34 exerts an influence. Therefore, rattling does not occur in these portions, and it is possible to prevent generation of abnormal noise and improve durability. Further, as to the mutual relationship between the tappet body 28 and the rotary member 30 in which the torsion spring 34 is interposed, at least one tappet body 28 constitutes a fixed system relative to the rotary member 30, so that the conventional structure is not provided. Unlike the assembling relationship in which the urging means is provided between the slide member and the rotating member, both of which operate as described above, rattling can be further suppressed.

Further, since the tappet body 28 is provided with the restriction portion for restricting the sliding amount of the slide member 32, the tappet 26 with respect to the rotary member 30 is increased as the clearance increases.
Member 32 relatively moved in the direction of extending
However, it can be prevented that the screwed state with the rotating member 30 cannot be maintained and that the rotating member 30 falls off.

Further, a tappet body 28, which is a main component of the tappet 26 and constitutes an outer shell of the tappet 26, is in contact with the cam 24, and a slide member 32 is in contact with the shaft end of the valve stem 22. The lubricating oil chamber 4 has a closed space formed by the guide member 40 surrounding the slide member 32 between the slide member 32 and the tappet body 28.
Since it is formed as 2, it is not necessary to separately provide a component that constitutes the lubrication system, and a simple configuration can be achieved.

Further, since a hexagonal hole 30b for rotating the rotating member 30 relative to the tappet body 28 is formed at the rotational axis position of the rotating member 30, a space between the rotating member 30 and the tappet body 28 is formed. With the torsion spring 34 provided in the tappet body 2, the rotating member 30 can be rotated against the torsion spring 34 with the hexagon wrench through the hexagonal hole 30b, and the biasing force of the torsion spring 34 can be initialized.
8 can be done freely from outside.

[0035]

In summary, according to the present invention, the biasing means for expanding and contracting the tappet due to the assembly structure are the tappet body that does not rotate or slide in the expansion and contraction operation of the tappet, and the rotation that only rotates with respect to this. Since it is arranged between the rotary member and the slide member, compared with the case where the biasing means is arranged between the rotary member and the slide member as in the conventional structure, at least between the rotary member and the slide member and the slide member. The elastic effect of the biasing means does not appear between the tappet main body and the tappet main body, and therefore rattling does not occur in these portions, and it is possible to prevent abnormal noise and improve durability. Further, as for the mutual relationship between the tappet body and the rotating member in which the biasing means is interposed, at least one tappet body constitutes a fixed system relative to the rotating member, and therefore, as in the conventional case, Unlike the assembling relationship in which the biasing means is provided between the sliding member and the rotating member that also operate, rattling can be further suppressed.

Further, since the tappet body is provided with the regulating portion for regulating the sliding amount of the slide member, the slide member which is relatively moved in the direction in which the tappet is extended with respect to the rotating member as the clearance is increased is different from the rotating member. It can be prevented that the screwed state cannot be maintained and is dropped.

Further, the main constituent parts of the tappet,
A tappet body that forms the outer shell of the tappet and is in contact with the cam; and a slide member that is in contact with the shaft end of the valve stem,
Since a closed space formed by the guide member surrounding the slide member and the slide member and the tappet body is formed as a lubricating oil chamber, it is not necessary to separately provide a component that constitutes the lubrication system, and a simple configuration is provided. Can be

Furthermore, at the rotational axis position of the rotary member,
Since the engaging portion for rotating the rotating member relative to the tappet body is formed, the urging member is urged through the engaging portion when the urging means is provided between the rotating member and the tappet body. The rotating member can be rotated against the means, and the initial setting of the biasing force of the biasing means can be freely performed from outside the tappet body.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a valve operating mechanism for an engine according to the present invention.

FIG. 2 is a sectional view taken along the line BB of FIG.

FIG. 3 is a vertical cross-sectional view showing a state of the tappet of FIG. 1 before extension.

FIG. 4 is a vertical cross-sectional view showing a state in which the tappet of FIG. 1 is expanded.

FIG. 5 is a vertical sectional view showing a conventional example.

[Explanation of symbols]

 22 Valve Stem 24 Cam 26 Tappet 28 Tappet Body 30 Rotating Member 30b Hexagonal Hole 32 Slide Member 34 Torsion Spring 36 Mounting Part 40 Guide Member 40b Sleeve 42 Lubricating Oil Chamber

Claims (5)

[Claims] 1. A tappet which is interposed between a cam and a shaft end of a valve stem to eliminate a clearance between the cam and the shaft end, and which expands and contracts along the axial direction of the valve stem in accordance with the bias of a biasing means. In a valve operating mechanism of an engine that has, a rotating member that is rotatably provided around the axis of the valve stem in a tappet body that is in contact with the cam, and is disposed between the rotating member and the tappet body. Urging means for urging the rotary member to rotate relative to the tappet body, and the tappet body slidably supported in the axial direction of the valve stem while the rotation of the tappet body is restricted by the rotary member. A valve operating mechanism for an engine, comprising: a slide member that is screwed into contact with the shaft end of the valve stem. 2. The rotating member is formed into a hollow cylindrical body along the axial direction of the valve stem, having an opening at the cam-side end that is closed by the tappet body, and the biasing member. The means is disposed inside the rotary member, while the slide member is formed into a hollow cylindrical body along the axial direction of the valve stem so as to be screwed into the rotary member from the outside, and the slide body is provided on the tappet body. The valve mechanism for an engine according to claim 1, further comprising a guide member that surrounds the slide member and guides the slide movement while restricting the rotation thereof. 3. The tappet main body is provided with a restriction portion, which is opposed to the slide member in the sliding direction, for restricting the slide amount of the slide member. The valve operating mechanism of the engine according to. 4. The tappet body, and a guide member provided on the tappet body for guiding the slide member,
The valve operating mechanism of the engine according to claim 2, wherein a lubricating oil chamber is defined by the slide member that is screwed onto the rotating member. 5. The rotating member is formed with an engaging portion for rotating the rotating member relative to the biasing means relative to the tappet main body, at an axis position of the rotating member. An engine valve mechanism according to any one of claims 1 to 4.