JP2002138808A - Direct acting valve system of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact and lightweight direct acting valve system capable of reducing a rotational axis directional dimension when fitting a switching means and a cam piece for adjacently arranging plural cams different in a cam profile in the rotational axis direction of a camshaft. SOLUTION: This direct acting valve system of an internal combustion engine has the cam piece 30 having first and second cam parts 37a and 37b adjacently arranged on the low speed cams 38a and 38b and the high speed cams 39a and 39b different in the cam profile, valve lifters 32a and 32b, and a driving piston 50 for selectively switching the cams for slidingly contacting with slipper parts 43a and 43b of the valve lifters 32a and 32b. Recessing cutout parts 42a1, 42a2 and 42b2 to the high speed cams 39a and 39b and a pair of arms 54a and 54b of the driving piston 50 in a noncontact state to the valve lifters pressed by sliding contact of the low speed cams 38a and 38b, are formed in the valve lifters 32a and 32b by a through-hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct drive of an internal combustion engine provided with a switching means for selectively switching valve operating characteristics of an intake valve or an exhaust valve which is an engine valve for controlling intake or exhaust provided in the internal combustion engine. The present invention relates to a valve actuation device.

[0002]

2. Description of the Related Art Conventionally, as a valve gear having a switching means for selectively switching the valve operating characteristics of an intake valve or an exhaust valve of an internal combustion engine, Japanese Patent Application No.
189489. The valve train of the prior application includes an intake cam piece having an intake variable cam portion provided adjacently to a low-speed cam and a high-speed cam, which are a plurality of cams having different cam profiles, provided on an intake cam shaft, and an exhaust cam. An exhaust cam piece having an exhaust variable cam portion provided adjacent to a low-speed cam and a high-speed cam which are provided on a shaft and having different cam profiles, and a low-speed cam of an intake variable cam portion and an exhaust variable cam portion. Or, it includes an intake rocker arm and an exhaust rocker arm that are in contact with the high-speed cam, and a drive mechanism that moves the intake cam piece and the exhaust cam piece that are movable with respect to the cam shaft in the rotation axis direction of the cam shaft.
Then, by moving the intake cam piece and the exhaust cam piece in the direction of the rotation axis, the intake rocker arm and the exhaust rocker arm which are selectively brought into contact with the low-speed cam or the high-speed cam of the intake cam piece and the exhaust cam piece to be swung, The intake and exhaust valves are actuated according to the cam profile of the low speed cam or high speed cam, respectively.

[0003]

By the way, the above-mentioned prior application discloses that the valve train may be of a direct drive type, whereby the intake valve and the exhaust valve at the time of high speed rotation are disclosed. Advantages are obtained, such as improved operation responsiveness, and a reduction in the height of the valve operating chamber, resulting in a compact internal combustion engine. However, in the direct-acting valve train, when the intake valve and the exhaust valve are operated by the intake cam piece and the exhaust cam piece in which a plurality of cams having different cam profiles are provided adjacent to each other, the intake valve (or the exhaust valve) is used. Valve) and the variable intake cam section (or variable exhaust cam section) interfere with a cam that is not in contact with the valve lifter, in particular, a high-speed cam protruding by a large amount compared to a low-speed cam, or The problem is how to avoid interference with a drive mechanism for moving each cam piece in the direction of the rotation axis of the cam shaft without increasing the size of the valve train.

The present invention has been made in view of such circumstances, and in the inventions according to claims 1 to 4, a plurality of cams having different cam profiles are provided in the rotation axis direction of the cam shaft. It is a common object to provide a compact and lightweight direct-acting valve train which can reduce the size in the direction of the rotation axis when the cam piece and the switching means are combined. A third object of the present invention is to provide a direct-acting valve train that reduces the weight of a valve lifter and facilitates lubrication of an engine valve. It is an object of the present invention to provide a compact direct-acting valve train in an internal combustion engine provided with two engine valves for controlling intake and exhaust with respect to a cylinder by sharing a cam piece and a switching means.

[0005]

The invention according to claim 1 of the present application is a cam piece which rotates together with a cam shaft, wherein a plurality of cams having different cam profiles are arranged in the direction of the rotation axis of the cam shaft. A cam piece having an adjacently provided cam portion, a valve lifter disposed between the cam portion and an engine valve that controls intake or exhaust of the internal combustion engine, and a cam that slides on the valve lifter of the cam portion. Switching means for selectively switching, wherein the valve lifter is provided with the valve lifter of the cam portion, wherein the valve lifter is operated in accordance with a cam profile of the cam with which the engine valve slides. The present invention is a direct-acting valve train for an internal combustion engine provided with a notch for escape for a cam that is not in contact with the cam.

According to the first aspect of the present invention, the cam in the non-contact state adjacent to the cam slidingly contacting the valve lifter of the cam piece rotates through the notch of the valve lifter without interfering with the valve lifter. . As a result, the following effects are obtained. That is, when one of the cam pieces provided with a plurality of cams having different cam profiles adjacent to each other slides on the valve lifter to operate the engine valve, the cam adjacent to the sliding contact passes through the cutout of the valve lifter. Therefore, it is possible to position at least a part of the cam adjacent to the sliding cam in the range of the width in the rotation axis direction of the cam shaft of the valve lifter, and to reduce the width of the cam piece in the rotation axis direction. As a result, the valve train can be made compact and lightweight, and thus the internal combustion engine can be made compact and lightweight. Furthermore, since the size of the cam piece in the direction of the rotation axis is small, even when a plurality of engine valves for controlling intake or exhaust are provided for the same cylinder, within a limited range of the bore diameter of the cylinder, It is easy to apply cam pieces to these multiple engine valves,
In addition, it is easy to provide three or more cams on the cam piece.

According to a second aspect of the present invention, there is provided a cam piece which rotates together with a cam shaft, wherein the cam piece has a cam portion provided with a plurality of cams having different cam profiles in a direction of a rotation axis of the cam shaft. A valve lifter disposed between a cam portion and an engine valve that controls intake or exhaust of the internal combustion engine; and switching means for selectively switching a cam of the cam portion that slides on the valve lifter. In a direct-acting valve train for an internal combustion engine operated in accordance with a cam profile of the contacting cam, the cam piece is movable in the direction of the rotation axis with respect to the cam shaft, and the switching means comprises a cam. An operating member that abuts a side surface of the portion in the direction of the rotation axis, and moving the cam piece in the direction of the rotation axis via the operation member to cut off the cam that is in sliding contact with the valve lifter. And a obtain driving member, said valve lifter, notch for relief against the operating member is a direct drive type valve operating system for an internal combustion engine provided.

According to the second aspect of the present invention, it is assumed that the operating member abuts on the side surface of the cam portion in the rotation axis direction at a position protruding radially outward from the base circular portion of the cam. Also, since it is located in the notch, it does not come into contact with the valve lifter. As a result, the following effects are obtained. That is, the operating member that comes into contact with the side surface of the cam portion does not need to be brought into contact with the valve lifter only on the side surface of the cam portion radially inward of the base circle portion of the cam, and the base of the cam is not required. Even when the operation member comes into contact with the side surface at a position protruding radially outward from the circular portion, the operation member can be positioned within the range of the width in the rotation axis direction of the cam shaft of the valve lifter. The width in the direction of the rotation axis together with the switching means having the bridge and the operating member can be reduced, so that the valve gear is compact and lightweight, and thus the internal combustion engine is compact and lightweight. Furthermore, since the side surface of the cam portion can be positioned within the range of the width of the valve lifter in the direction of the rotation axis, the switching means having an operating member abutting on the side surface of the cam portion can reduce the width of the cam piece in the direction of the rotation axis. Does not hinder the compactness of the valve train due to the shortening of the length. Further, in setting the contact portion of the operation member on the side surface of the cam portion, restrictions on the positional relationship between the operation member and the valve lifter are reduced, and the degree of freedom of the arrangement of the operation member and, consequently, the degree of freedom of the arrangement of the switching means are reduced. Becomes larger.

According to a third aspect of the present invention, in the direct-acting type valve train for an internal combustion engine according to the first or second aspect, the cutout portion penetrates the valve lifter to communicate the inside and the outside. It is formed by

[0010] According to the third aspect of the invention, the lubricating oil outside the valve lifter enters the inside of the valve lifter through the cutout formed by the hole provided in the valve lifter, and the valve spring is disposed inside the valve lifter. Lubricating oil is easily supplied to the retainer and the sliding portion of the engine valve. Further, since the hole is formed, a part of the valve lifter is cut off, so that the valve lifter is reduced in weight. As a result, the following effect is obtained in addition to the effect of the invention described in claim 1 or 2. That is, since the lubricating oil can be easily supplied to the sliding portion inside the valve lifter through the notch portion, the durability of the sliding portion is improved. Furthermore, since a part of the valve lifter is cut off by the formation of the notch, the weight of the valve lifter can be reduced, and the weight of the internal combustion engine can be reduced.

According to a fourth aspect of the present invention, in the direct-acting valve train for an internal combustion engine according to any one of the first to third aspects, the cam portion is formed in the cam piece in the direction of the rotation axis. A first cam portion and a second cam portion provided in series, wherein the engine valves are a first engine valve and a second engine valve provided for the same cylinder, and the valve lifter is provided with the first engine portion; A first valve lifter disposed between a valve and the first cam portion, and a second valve lifter disposed between the second engine valve and the second cam portion, wherein the same switching means includes: The cams that are in sliding contact with the first valve lifter and the second valve lifter, respectively, are selectively switched.

According to the fourth aspect of the present invention, the first engine valve and the second engine valve provided in the same cylinder are:
A plurality of cams constituting the first cam portion and the second cam portion provided on the same cam piece are selectively and simultaneously switched by the same switching means. As a result, the following effects are achieved in addition to the effects of the invention described in the cited claims. That is, the first and the second provided in the same cylinder
The engine valve is operated by one of the plurality of cams of the first and second cam portions provided on the same cam piece, which is switched by the same switching means so as to be in sliding contact with the first and second valve lifters. Therefore, the cam piece and the switching means can be shared for the two engine valves, and the valve train can be made compact.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. An internal combustion engine E to which the direct-acting valve train of the present invention is applied is a DOH mounted on a vehicle.
1 is a C-type in-line 4-cylinder 4-cycle internal combustion engine. As shown in FIG.
The cylinder head 3 is assembled on the upper surface of the cylinder block 2 (one of which is shown in FIG. 1), and the head cover 4 is assembled on the upper surface of the cylinder head 3. A piston 5 reciprocally fitted in the bore 1a of each cylinder 1 is connected to a crankshaft (not shown) via a connecting rod (not shown), and is halved in synchronization with the crankshaft. An intake camshaft 6 and an exhaust camshaft 7, which are driven to rotate at a reduction ratio of 5, are arranged in parallel with each other in the cylinder arrangement direction, and are fixed to the cylinder head 3 by five cam holders 8 (one of which is shown in FIG. 1). ) Is rotatably supported. The cam holders 8 are arranged at both ends in the cylinder arrangement direction and between the adjacent cylinders 1. Each cam holder 8 has a plane including a rotation axis L1 of the intake camshaft 6 and a rotation axis L2 of the exhaust camshaft 7. The upper cam holder 8U and the lower cam holder 8L are vertically divided.

The cylinder head 3 includes, for each cylinder 1,
A combustion chamber 9 is formed between the piston 5 and the combustion chamber 9, and an intake port 10 having a pair of intake ports and an exhaust port 11 having a pair of exhaust ports are provided in the combustion chamber 9. The first intake valve 12a and the second intake valve 12b (see FIG. 2), which are a pair of engine valves for controlling the intake of the internal combustion engine E, respectively, and the pair of exhaust ports are respectively opened and closed. Then, a first exhaust valve 13a and a second exhaust valve (not shown), which are a pair of engine valves for controlling the exhaust of the internal combustion engine E, are slidably provided on the valve guides 14a and 15a. The first and second intake valves 12a, 12b, the first exhaust valve 13a, and the second exhaust valve are respectively provided with retainers 18a, 18b, 19a provided at the upper ends of the valve stems 16a, 17a and the cylinder head 3a. Are biased in the valve closing direction by valve springs 20a, 20b, 21a mounted in a compressed state. Also, the cylinder head 3
, An ignition plug 22 facing substantially the center in the combustion chamber 9 is screwed.

A valve operating chamber 23 formed between the cylinder head 3 and the head cover 4 accommodates a direct-acting valve operating device V for opening and closing the intake valves 12a, 12b and the exhaust valve 13a. The valve gear V includes an intake cam shaft 6, an intake cam piece
30, an intake valve lifter 32 a, 32 b, and an intake side valve train V _{IN including} a hydraulic intake side drive mechanism M _IN as intake side switching means for moving the intake cam piece 30 in the direction of the rotation axis L 1 of the intake camshaft 6. And the exhaust cam shaft 7, the exhaust cam piece 31, the exhaust valve lifter 33a, and the exhaust cam piece 31
Made from an exhaust side valve system V _EX of an exhaust-side drive mechanism M _EX hydraulic as an exhaust-side switching means for moving in the direction of the rotational axis. The intake-side valve operating device V _IN and the exhaust-side valve operating device V _EX have basically the same configuration. Therefore, in the following description, the intake-side valve operating device V _IN will be mainly described.

Referring also to FIG. 2, the intake camshaft 6 has, for each cylinder 1, an intake cam piece 30 having a shaft hole 34 through which the intake camshaft 6 passes.
They are spline-coupled so that they can slide freely in the L1 direction and rotate integrally with the intake camshaft 6 in the rotation direction. Therefore, in this embodiment, on the inner peripheral surface of the intake cam piece 30, three concave grooves 35 are provided at equal intervals in the circumferential direction and parallel to the rotational axis L1 over the entire length in the direction of the rotational axis L1. And
On the outer peripheral surface of the intake camshaft 6, three protrusions 36 respectively engaging with the three concave grooves 35 are provided over a length equal to the moving range of the intake cam piece 30 in the direction of the rotation axis L1. .

The intake cam piece 30 is provided with a first intake cam portion 37a and a second intake cam portion 37b in series in the direction of the rotation axis L1 and separated from each other, and the first and second intake cam portions 37a, 37b are provided. Low speed cams 38a, 38
8b and the high-speed cams 39a and 39b are integrally provided adjacent to each other in the direction of the rotation axis L1. That is, each of the low-speed cams 38a and 38b has a relatively small protrusion amount in the radial direction (hereinafter, simply referred to as “radial direction”) of the intake camshaft 6 and a nose portion having a predetermined operating angle in the circumferential direction, and a base. Each of the high-speed cams 39a and 39b has a radially protruding amount larger than that of a nose portion of the low-speed cams 38a and 38b.
The cam profile has a nose portion having an operating angle larger than that of the low-speed cams 38a and 38b, and a base circular portion having the same radial projection as the base circular portion of the low-speed cams 38a and 38b. .

Further, the intake cam piece 30 includes a low speed cam 38.
a, 38b and a high-speed cam 39a, 39b. Cam 38a
Second side of the second intake cam portion 37b constituting the other side in the direction of the rotation axis L1 on the side of the high-speed cam 39b.
First extending from both sides of 40b in the direction of the rotation axis L1
A cylindrical portion 41a and a second cylindrical portion 41b are provided.

Further, below the intake cam piece 30,
A first intake valve lifter 32a is disposed between the first intake cam portion 37a and the first intake valve 12a for each cylinder 1, and a second intake valve lifter 32a is disposed between the second intake cam portion 37b and the second intake valve 12b. An intake valve lifter 32b is provided. The first and second intake valve lifters 32a and 32b are slidably fitted in lifter holes provided in the cylinder head 3 in the axial direction of the valve stems 16a and 16b, respectively.

Each intake valve lifter 32a, 32b has a cylinder having an open lower end and a top wall at the upper end, and has a plane symmetrical with respect to an orthogonal plane that includes the axis of the cylinder and is orthogonal to the rotation axis L1 of the intake camshaft 6. In this case, the side wall from the top wall to the approximate center of the length of the cylinder is cut off on both sides in the direction of the rotation axis L1. A pair of cutouts 42a1, 42a2, 42b1, 42b2 formed by the cut are formed as through holes communicating the outside and the inside of each intake valve lifter 32a, 32b. The lubricating oil supplied to 23 enters the inside of each intake valve lifter 32a, 32b, and the valve springs 20a, 20b, the retainers 18a, 18b and the valve stems 16a, 16a
Lubricate the sliding part of 6b.

The remaining portion of the top wall is a low-speed cam.
Bridge-shaped slipper portions 43a and 43b are formed so that 38a and 38b and high-speed cams 39a and 39b are in sliding contact with each other. The bridge-shaped slipper portions 43a and 43b have both end surfaces extending in parallel with the orthogonal plane and extend in the diameter direction of the top wall. The slipper portions 43a and 43b have a width in the direction of the rotation axis L1 slightly smaller than the width of the low-speed cams 38a and 38b and the high-speed cams 39a and 39b in the direction of the rotation axis L1. 43a1 and 43b1 have an outer surface of a top wall parallel to the rotation axis L1 of the intake camshaft 6 and have an axis on a plane including the axis of the cylinder, and are convex toward each of the intake cam portions 37a and 37b. When viewed from the direction of the rotation axis L1, it has a circular arc that is convex toward each of the intake cam portions 37a and 37b.

As shown in FIG. 3, the notches 42a2 and 42b2 are provided with the low-speed cams of the first and second intake cams 37a and 37b.
When the sliding parts 38a, 38b are in sliding contact with the slipper parts 43a, 43b, the nose parts of the high-speed cams 39a, 39b projecting in the radial direction larger than the nose parts of the low-speed cams 38a, 38b form the first and second intake valve lifters 32a. , 32b are formed so as to pass through without contact with each other, and serve as notches for escape to the high-speed cams 39a, 39b. And both intake cams 37
a, 37b in the direction of the rotation axis L1, that is, the low-speed cam 38
The sum of the widths of the intake valve lifters 32a and 32b in the direction of the rotation axis L1 is smaller than the total width of the intake valve lifters 32a and 32b in the direction of the rotation axis L1. Further, the notches 42a1, 42
a2, 42b1, 42b2, the retainers 18a, 18b are positioned close to the maximum protrusion of the nose of the high-speed cams 39a, 39b passing through the cutouts 42a2, 42b2.
Sliding contact surfaces 43a1, 43 between the end portions of 16a, 16b and the slipper portions 43a, 43b
The distance between b1 and b1 is made as small as possible to make the valve train V compact.

Further, referring to FIGS. 1 and 2, on the side walls of the first and second intake valve lifters 32a and 32b, formed on the peripheral wall surface of the lift hole so as to extend in parallel with the axis of the valve stems 16a and 16b. A first pin 44a and a second pin 44b are provided to engage with the first guide groove 24a and the second guide groove, respectively. The first guide groove 24a and the second guide groove are connected to the first pin 44a and the second pin 44b, respectively.
a, 32b while the intake valve lifter 32
The valve stems 16a, 16b of a, 32b are allowed to reciprocate in the axial direction. The exhaust valve lifter also has a cylinder head 3
The first guide groove 25a and the first pin 45a are shown in FIG.

Therefore, the low speed cams 38a and 38b and the high speed cams 39a and 39b of the first and second intake cam portions 37a and 37b are moved by the intake cam piece 30 moved in the direction of the rotation axis L1 by the intake side drive mechanism M _IN. Selectively slidingly contact the slipper portions 43a, 43b, and the first and second intake valves 12a, 12b are pressed by the low-speed cams 38a, 38b or the high-speed cams 39a, 39b. , And operates in accordance with the cam profiles of the cams that come into sliding contact with each other to open and close the intake port with a lift amount and opening / closing timing set at the nose portion of each cam.

Next, referring to FIG. 2, FIG. 5 and FIG.
The intake-side drive mechanism M _IN provided for each cylinder 1 will be described. The intake-side drive mechanism M _IN is located on both sides of the intake cam piece 30 and protrudes in the opposite direction of the adjacent upper cam holder 8U. In the boss portion, a first cylinder portion 51a and a second cylinder portion 51b having cylindrical concave portions provided to face each other closer to the center axis of the cylinder 1 than the intake camshaft 6, and the two cylinder portions 51a, 51b. A double-acting drive piston 50 as a movable member having a cylindrical first piston portion 52a and a second piston portion 52b, both ends of which are slidably fitted and supported, and a center of the drive piston 50 In a connecting portion 53 extending in the axial direction and connecting the piston portions 52a and 52b, an operating member formed integrally with the piston portions 52a and 52b together with the connecting portion 53 and extending from the connecting portion 53 toward the intake cam shaft 6. is there Pair of arms 54a, 5
4b. Here, the center axis of the drive piston 50 is
The rotation axis L1 of the intake camshaft 6 is parallel to the rotation axis L1.
The central axes of the second cylinder portions 51a and 51b are coincident with each other.

[0026] Further, between the first piston portion 52a and the first cylinder portion 51a is provided between the first hydraulic chamber _55a, but also the second piston portion 52b and the second cylinder portion 51b second hydraulic chamber 55b
Are respectively formed, and the drive piston 50 is
The drive piston 50 reciprocates along the central axis of the drive piston 50 by receiving a drive force corresponding to the hydraulic pressure of the working oil supplied to the a and 55b.

A pair of arms 54a and 54b, which are provided at intervals slightly larger than the length of the intake cam piece 30 in the direction of the rotation axis L1 in the direction of the center axis of the drive piston 50,
A first arm 54a located on the side of the side surface 40a;
The second arm 54b is located on the side of b. The first and second arms 54a and 54b are connected to the first and second cylindrical portions 41a and 41b.
Are provided with a pair of forked operation parts 56a1 and 56a2 and a pair of operation parts 56b1 and 56b2, respectively.

The distal ends of both operating portions 56a1 and 56a2 of the first arm 54a are connected to the first side surface 40 of the low speed cam 38a of the first intake cam portion 37a.
1 that abuts against the outer peripheral surface of the first cylindrical portion 41a
It has a pair of first contact portions 57a1 and 57a2, respectively, and the first contact portions 57a1 and 57a2 are located at positions where the distance from the rotation axis L1 is equal and at a position facing the diametrical direction of the intake camshaft 6. First
It contacts the side surface 40a and the outer peripheral surface of the first cylindrical portion 41a. Similarly, the distal ends of both operation portions 56b1 and 56b2 of the second arm 54b are
The second intake cam portion 37b has a pair of second contact portions 57b1 and 57b2 that contact the second side surface 40b of the high-speed cam 39b and the outer peripheral surface of the second cylindrical portion 41b. Contact 57b
1, 57b2 are the second side surfaces 40 at positions where the distance from the rotation axis L1 is equal and at the position facing the intake cam shaft 6 in the diametrical direction.
b and the outer peripheral surface of the second cylindrical portion 41b.

In the drive piston 50, between the first arm 54a and the second arm 54b, the rotating low-speed cams 38a and 38b and the rotating high-speed cams 39a and 39b bite into the connecting portion 53. Thus, a curved concave portion 57 (see also FIG. 1) which allows the low-speed cams 38a and 38b and the high-speed cams 39a and 39b to pass therethrough is provided.

Next, the hydraulic system of the intake-side drive mechanism M _IN will be described. The cylinder block 2, the cylinder head 3 and the cam holder are provided in the discharge path of an oil pump provided in the internal combustion engine E and driven by the power of a crankshaft. 8, a hydraulic oil passage (not shown) having an opening 58a communicates with the first hydraulic chamber 55a. The first control valve (not shown) provided in the hydraulic oil passage causes the first hydraulic The operating oil pressure of the chamber 55a is controlled to a high oil pressure or a low oil pressure. Similarly, the second
The hydraulic pressure in the second hydraulic chamber 55b is controlled to a high hydraulic pressure or a low hydraulic pressure by a second control valve (not shown) provided in a second hydraulic oil passage (not shown) having an opening 58b in the hydraulic chamber 55b. Is done.

The operation of the first and second control valves is controlled by a control device (not shown) to which a signal detected by a rotation speed sensor, which is an engine operation state sensor (not shown), is input. That is, in the low-speed rotation region of the internal combustion engine E that is equal to or lower than the predetermined rotation speed, the first control valve is connected to the first hydraulic chamber 55.
The hydraulic pressure of the hydraulic oil is controlled so that the hydraulic oil in a becomes high, and the second control valve controls the hydraulic pressure of the hydraulic oil so that the hydraulic oil in the second hydraulic chamber 55b becomes low. Therefore, the first
Due to the difference between the oil pressure in the hydraulic chamber 55a and the oil pressure in the second hydraulic chamber 55b, the drive piston 50 moves the intake cam piece 30 in the axial direction, and the intake cam piece 30 is moved by the low-speed cams 38a, 38b. Are the slipper portions 43a, 43 of the first and second intake valve lifters 32a, 32b.
5b occupies the low speed position shown in FIG. At this time, as shown in FIG. 3, the first intake cam portion 37a
Abuts against the first side surface 40a of the low-speed cam 38a, and the first cylindrical portion 41
Of the pair of operating portions 56a1 and 56a2 surrounding a, the operating portion 56a2 and the contact portion 57a2 near the first intake valve lifter 32a are projected radially beyond the base circle portion of the low-speed cam 38a. Since it is located in the notch 42a1, it does not come into contact with the first intake valve lifter 32a. Therefore, notch 4
2a1 also serves as a notch for escape to the operation part 56a2 and the contact part 57a2, and eventually to the first arm 54a.

When the rotation speed of the internal combustion engine E exceeds the predetermined rotation speed and enters a high-speed rotation range, the first control valve:
The hydraulic pressure of the hydraulic oil is controlled so that the first hydraulic chamber 55a has a low hydraulic pressure, and the second control valve controls the hydraulic pressure of the hydraulic oil so that the second hydraulic chamber 55b has a high hydraulic pressure. For this reason, the first hydraulic chamber 55
Due to the oil pressure difference between the oil pressure in a and the oil pressure in the second hydraulic chamber 55b,
The drive piston 50 _IN is to move the intake cam piece 30 in the axial direction, the intake cam piece 30, both fast cams 39a, 39b are brought into sliding contact with the first, second intake valve lifter 32a, 32b of the slipper portion 43a, 43b , Occupy the high speed position illustrated in FIG. And
At this time, as shown in FIG.
b, abuts against the second side surface 40b of the high-speed cam 39b, and the second cylindrical portion 4
Of the pair of operating portions 56b1 and 56b2 surrounding 1b, the operating portion 56b2 and the contact portion 57b2 near the second intake valve lifter 32b are projected in the radial direction from the base circular portion of the high-speed cam 39b. Since it is located in the notch 42b2, it does not come into contact with the second intake valve lifter 32b. Therefore, notch 4
2b2 also serves as a notch for escape to the operation part 56b2 and the contact part 57b2, and eventually to the second arm 54b.

Here, the first and second intake valve lifters 32
a, 32b shifts from pressing by sliding contact of the low-speed cams 38a, 38b to pressing by sliding contact of the high-speed cams 39a, 39b;
The transition from pressing by sliding contact of 39a, 39b to pressing by sliding contact of low-speed cams 38a, 38b is caused by the contact portion of slipper portions 43a, 43b,
Base circle of low-speed cams 38a, 38b or high-speed cams 39a, 39b
The driving force received by the driving piston 50 is set so as to be performed at the time when the driving piston 50 is in sliding contact with the base circle portion.

As shown in FIGS. 5 and 6, the cam holder 8 located between the adjacent cylinders 1 passes through the center point of the cam holder 8 in the direction of the rotation axis L1, and With respect to a plane perpendicular to L1, the first hydraulic chamber 55a belonging to the cylinder 1 on the right side of the figure and the first hydraulic chamber 55a belonging to the cylinder 1 on the left side of the upper cam holder 8U are plane-symmetric. The hydraulic oil passages are shared by the two hydraulic chambers 55a, 55a. This means that the other cam holders 8 located between adjacent cylinders 1
The same applies to the components of the valve gear V belonging to the cylinder 1.

The hydraulic system of the exhaust-side drive mechanism M _EX of the exhaust-side valve train V _EX is also supplied with controlled hydraulic oil in the same manner as the intake-side drive mechanism M _IN described above. I have.

Next, the operation of the embodiment configured as described above will be described with reference to FIGS. In the state where the operation of the internal combustion engine E is started and the oil pump is operating, and the rotation speed of the internal combustion engine E is in the low-speed rotation range equal to or lower than the predetermined rotation speed, the intake-side valve operating device V _IN includes a control device. , The first control valve operates such that the hydraulic oil in the first hydraulic chamber 55a has a high hydraulic pressure, and at the same time, the second control valve has the hydraulic oil in the second hydraulic chamber 55b having a low hydraulic pressure. Works as follows. Therefore, the drive piston 50 of the intake-side drive mechanism M _IN occupies the low-speed position shown in FIG. Therefore, the intake cam piece 30
Low-speed cams 38a, 38b of the first and second intake cam portions 37a, 37b
Are the slipper portions of the first and second intake valve lifters 32a and 32b.
It comes into sliding contact with 43a and 43b, respectively. The drive piston of the exhaust-side drive mechanism M _EX also occupies the low-speed position, which is the state before the start of operation of the internal combustion engine E, similarly to the intake-side drive mechanism M _IN . Therefore, the first and second intake valves in each cylinder 1
The 12a, 12b, the first exhaust valve 13a, and the second exhaust valve are opened and closed with a small lift amount, opening / closing timing, and a short valve opening period that are suitable for valve operating characteristics in a low-speed rotation range. At this time, as shown in FIG. 3, the nose portions of the high-speed cams 39a and 39b projecting radially larger than the nose portions of the low-speed cams 38a and 38b are connected to the first and second intake valve lifters 32a and 32b. Without passing through the notches 42a2 and 42b2, respectively. Then, the operation unit 56a near the first intake valve lifter 32a
2 and the contact portion 57a2 are located in the cutout portion 42a1 despite protruding in the radial direction from the base circular portion of the low-speed cam 38a, and therefore do not contact the first intake valve lifter 32a. Moreover, this also applies to the exhaust-side valve operating device V _EX.

When the rotational speed of the internal combustion engine E exceeds the predetermined rotational speed and shifts to a high-speed rotation range, the first control valve operates according to a command from the control device to change the operating oil in the first hydraulic chamber 55a. The second control valve operates so that the hydraulic pressure becomes low, and at the same time, the second control valve operates so that the hydraulic oil in the second hydraulic chamber 55b becomes high hydraulic pressure. Therefore, the drive piston of the intake side drive mechanism M _IN
A driving force 50 moves from the low speed position to the high speed position shown in FIG.

At this time, the first and second intake valve lifters 32
If the slipper portions 43a and 43b of the a and 32b are in sliding contact with the base circular portions of the low-speed cams 38a and 38b, the drive piston 50 immediately moves, and at the same time, a pair of contact portions 57b1 and 57b2 of the second arm 54b.
The driving force acts on the intake cam piece 30 in the direction of the rotation axis L1. As shown in FIG. 6, the intake cam piece 30 has the high-speed cams 39a and 39b connected to the first and second intake valve lifters 32.
It occupies the position in sliding contact with a and 32b.

When the driving piston 50 receives a driving force for moving from the low-speed position to the high-speed position, each of the slipper portions 43
If the a and 43b are in sliding contact with the nose portions of the low-speed cams 38a and 38b, the rotation of the intake cam shaft 6 causes the slipper portions to rotate.
Immediately after the 43a and 43b slide on the base circle portions of the low-speed cams 38a and 38b, the drive piston 50 moves toward the high-speed position, and at the same time, the driving force is applied via the contact portions 57b1 and 57b2 of the second arms 54a and 54b. The suction cam piece 30 on which the high-speed cams 39a, 39b slide is in contact with the slipper portions 43a, 43b.
Move in the direction. Therefore, in the high-speed rotation range, the high-speed cams 39a, 3a of the first and second intake cam portions 37a, 37b of the intake cam piece 30 are formed.
9b comes into sliding contact with the slipper portions 43a and 43b of the first and second intake valve lifters 32a and 32b, respectively. And the drive piston of the exhaust side drive mechanism M _EX is also similar to the intake side drive mechanism M _IN ,
Occupy the fast position. Therefore, the first and second intake valves 12a, 12b, the first exhaust valve 13a, and the second exhaust valve in each cylinder 1 have a large lift amount, opening / closing timing, and long valve opening adapted to valve operating characteristics in a high-speed rotation range. It is opened and closed in a period. Also,
At this time, as shown in FIG. 4, the operating portion 56b2 and the contact portion 57b2 near the second intake valve lifter 32b are notched despite the fact that they protrude radially beyond the base circle portion of the high-speed cam 39b. Since it is located at the portion 42b2, it does not come into contact with the second intake valve lifter 32b. Moreover, this also applies to the exhaust-side valve operating device V _EX.

Further, when shifting from the high-speed rotation range to the low-speed rotation range, the first and second control valves operate the first hydraulic chamber 55a.
The hydraulic oil in the second hydraulic chamber 55b has a high hydraulic pressure while the hydraulic oil in the second hydraulic chamber 55b has a low hydraulic pressure. Therefore, the drive piston 50 of the intake-side drive mechanism M _IN receives a drive force that moves from the high-speed position to the low-speed position due to the difference between the hydraulic pressure in the first hydraulic chamber 55a and the hydraulic pressure in the second hydraulic chamber 55b. At this time, as long as the slipper portions 43a, 43b of the first and second intake valve lifters 32a, 32b are in sliding contact with the base circle portions of the high-speed cams 39a, 39b, the respective slipper portions 43a, 43b are immediately connected to the high-speed cams 39a, 43b. If the nose of 39b is in sliding contact, each slipper 43a, 43b
Immediately after sliding on the base circles of a and 39b, drive piston 50
Moves toward the low-speed position, and at the same time, the intake cam piece 30 on which the driving force acts via the contact portions 57a1 and 57a2 of the first arm 54a.
Moves in the direction of the rotation axis L1 toward a low-speed position where the low-speed cams 38a and 38b are in sliding contact with the respective slipper portions 43a and 43b. Also in the exhaust-side valve operating device V _EX, it is made the same migration and the intake-side valve operating device V _IN above.

Next, the effect of the embodiment configured as described above will be described. Note that the description related to the exhaust-side valve train V _EX is given in parentheses, and the reference numerals are only those related to the intake-side valve train V _IN .

Low speed cams 38a, 38b of the intake (exhaust) cam piece 30
Are in sliding contact with the first and second intake (exhaust) valve lifters 32a and 32b, the first and second intake (exhaust) valve lifters 32a and 32b are adjacent to the low speed cams 38a and 38b.
The high-speed cams 39a, 39b in a non-contact state with the second intake (exhaust) valve lifters 32a, 32b do not interfere with both intake (exhaust) valve lifters 32a, 32b, and are notched 42a2, 42b2.
Rotate through. As a result, the following effects are obtained.
That is, the low-speed cams 38a and 38b having different cam profiles
The low-speed cams 38a, 38b of the intake (exhaust) cam piece 30 having the first intake (exhaust) cam portion 37a and the second (exhaust) intake cam portion 37b provided with the high-speed cams 39a, 39b adjacent to each other, When the first and second intake (exhaust) valves 12a and 12b are operated by sliding contact with the first and second intake (exhaust) valve lifters 32a and 32b, respectively, the high speed cams 39a and 38b adjacent to the low speed cams 38a and 38b that are in sliding contact with each other. Since 39b passes through the notches 42a2 and 42b2 of both intake (exhaust) valve lifters 32a and 32b, the first and second intake (exhaust) cam portions 37a and 37b and each intake (exhaust) valve lifter 32
The width of the intake (exhaust) cam piece 30 in the direction of the rotation axis L1 can be reduced by allowing the a (32b) to be positioned within the range of the width of the intake (exhaust) camshaft 6 in the direction of the rotation axis L1. And the valve gear V becomes compact and lightweight,
Consequently, the internal combustion engine E is compact and lightweight. Further, since the size of the intake (exhaust) cam piece 30 in the direction of the rotation axis L1 is small, the first and second
Even when the intake valves 12a, 12b, the first exhaust valve 13a, and the second exhaust valve are provided, the intake cam piece 30 for the plurality of intake valves and exhaust valves is limited within the limited bore 1a diameter of the cylinder 1. Also, the application of the exhaust cam piece 31 is easy.

The operating portions 56a2, 56b2 and the contact portions 57a2, 57b2 of the pair of arms 54a, 54b of the intake (exhaust) side driving mechanism M _IN.
Although the first and second side surfaces 40a and 40b of the intake (exhaust) cam piece 30 project radially outward from the base circle portions of the low-speed cams 38a and 38b and the high-speed cams 39a and 39b, Since they are located in the notches 42a1 and 42b2, they do not come into contact with the first and second intake (exhaust) valve lifters 32a and 32b. As a result, the following effects are obtained. That is, a pair of arms 54a, 54b abutting on the first and second side surfaces 40a, 40b of the intake (exhaust) cam piece 30 are connected to the first and second intake (exhaust) valve lifters 32.
a, 32b without contact with the intake (exhaust) cam piece
In the first and second side surfaces 40a, 40b of 30, it is not necessary to abut only on the radial inside of the base circular portions of the low-speed cam 38a and the high-speed cam 39b, and the base circular portions of the low-speed cam 38a and the high-speed cam 39b. Even if it comes into contact with the first and second side surfaces 40a, 40b at a position protruding more radially outward, the operating portions 56a2, 56b2 and the contact portion 57a of the pair of arms 54a, 54b.
2, 57b2 are replaced with first and second intake (exhaust) valve lifters 32a, 32
b can be located within the range of the width in the direction of the rotation axis L1 and the intake (exhaust) cam piece 30 and the operation units 56a2, 56
The width in the direction of the rotation axis L1 in combination with the intake (exhaust) side drive mechanism M _IN having the b2 and the contact portions 57a2 and 57b2 can be reduced, and the valve train V becomes compact and lightweight. Consequently, the internal combustion engine E is compact and lightweight. Furthermore, the first and second side surfaces 40a and 40b of the intake cam piece 30 can be positioned within the range of the width of the first and second intake (exhaust) valve lifters 32a and 32b in the direction of the rotation axis L1. (Exhaust) side drive mechanism M having the arm 54a and the arm 54b
_IN does not hinder the compactness of the valve train V by shortening the width of the intake (exhaust) cam piece 30 in the direction of the rotation axis L1. Further, both arms 54 on the first and second side surfaces 40a and 40b are provided.
When setting the contact portions of the a and 54b, the arms 54
a, 54b and first and second intake (exhaust) valve lifters 32a, 32b
Restrictions on the positional relationship with the arm 54a, 54b
Degree of freedom of arrangement of the motor, and thus the intake (exhaust) side drive mechanism M _IN
The degree of freedom in the arrangement of the elements increases.

First and second intake (exhaust) valve lifters 32
a, 32a, notches 42a1, 42a2,
The lubricating oil outside the first and second intake (exhaust) valve lifters 32a and 32b in the valve operating chamber 23 passes through the first and second lubricating oils through the valves 42b1 and 42b2.
Penetrating into the intake (exhaust) valve lifters 32a and 32b,
Valve springs 20a, 20b and retainers 18a, 1
Lubricating oil is easily supplied to the sliding portions of the intake valve 8b and the first and second intake valves 12a and 12b. Also, the notch 42a1, which is a through hole,
By forming 42a2, 42b1, 42b2, both intakes (exhaust)
Since a part of the valve lifters 32a and 32b is cut off, the valve lifters 32a and 32b are reduced in weight. As a result, the following effects are obtained. That is, the notches 42a1, 42a2, 42b1, 42
The first and second intake (exhaust) valve lifters 32a, 32a through b2
Since lubricating oil can be easily supplied to the sliding portion inside 2b, the durability of the sliding portion is improved. Further, the notches 42a1, 42a
Since a part of the first and second intake (exhaust) valve lifters 32a and 32b is cut off by the formation of 2, 42b1 and 42b2, the valve lifters 32a and 32b are reduced in weight, and the internal combustion engine E is further reduced.
Can be reduced in weight.

The first intake (exhaust) valve 12a and the second intake (exhaust) valve 12b provided on the same cylinder 1 are connected to the first intake (exhaust) cam provided on the same intake (exhaust) cam piece 30. The low-speed cams 38a and 38b and the high-speed cams 39a and 39b constituting the portion 37a and the second intake (exhaust) cam portion 37b are selectively and simultaneously switched by the same intake (exhaust) side drive mechanism M _IN . As a result, the following effects are obtained. That is, the first and second intake (exhaust) valves 12a and 12b provided in the same cylinder 1 are provided on the same intake (exhaust) cam piece 30 by the same intake (exhaust) side drive mechanism M _IN. Low-speed cam 38 of the first and second intake (exhaust) cam portions 37a, 37b
a, 38b and the high-speed cams 39a, 39b are operated by the cams that are switched so as to be in sliding contact with the first and second intake (exhaust) valve lifters 32a, 32b.
The intake (exhaust) cam piece 30 and the intake (exhaust) side drive mechanism M _IN can be shared for the 12a and 12b, and the valve train V can be made compact.

First and second intake (exhaust) valve lifters 32
The sliding surfaces 43a1 and 43b1 of the slipper portions 43a and 43b of the a and 32b are curved surfaces formed of cylindrical surfaces that are convex toward the first and second intake (exhaust) cam portions 37a and 37b. Each intake (exhaust) valve lifter 32 compared to the case where the contact surface is flat
a, 32b can be reduced in diameter, and the cylinder head 3
Can be reduced in size. In addition, despite the notches 42a1, 42a2, 42b1, 42b2 comprising through holes provided on the sides of the slippers 43a, 43b, the required rigidity of the slippers 43a, 43b is reduced.
There is an effect that the weight can be secured while achieving the weight reduction without increasing the weight such as increasing the thickness of the slipper portions 43a and 43b.

First and second intake (exhaust) valve lifters 32
a, 32b notches 42a1, 42a2, 42b1, 42b2
The retainers 18a, 18b are positioned close to the maximum protrusion of the nose of the high-speed cams 39a, 39b passing through 42a2, 42b2, and the ends of the valve stems 16a, 16b and the slipper 43
Since the distance between the sliding surfaces 43a1 and 43b1 of the a and 43b is made as small as possible, the effect that the valve train V can be made compact can be obtained.

Hereinafter, an embodiment in which a part of the configuration of the above-described embodiment is changed will be described with respect to the changed configuration.

In the above embodiment, the low-speed cam and the high-speed cam are in sliding contact with the outer surfaces of the slipper portions of the intake and exhaust valve lifters. However, the intake-side valve train V _IN is shown in FIG. First and second rollers 60a and 60b are provided on the top walls of the first and second intake valve lifters 32a and 32b, and the low-speed cams 38a and 38b and the high-speed cams 39a and 39b slide on the rollers 60a and 60b, respectively. A valve lifter configured to be in contact may be used. That is, the first and second support shafts 61 fixed to the first and second intake valve lifters 32a and 32b, respectively.
The first and second rollers 60a and 60b supported by the first and second rollers 60a and 60b partially protrude from the outer surface of the top wall and are in sliding contact with the low-speed cams 38a and 38b and the high-speed cams 39a and 39b. Outer ring 62a, 6
2b and the first and second shafts 61a and 61b respectively fitted.
It comprises inner rings 63a and 63b, and a number of rollers 64a and 64b provided between each outer ring 62a and 62b and each inner ring 63a and 63b. Further, the exhaust valve lifter is used that has a similar roller even in the exhaust-side valve operating device V _EX. With this configuration, the friction between the valve lifter and the cam is reduced, and the output loss can be reduced.

Further, as shown in FIG. 8, in the intake side drive mechanism M _IN , the high speed cam 39a
One or a plurality of reinforcing ribs 70 extending in the direction of the rotation axis L1 and connecting the first and second intake cam portions 37a, 37b may be provided between the low speed cam 38b and the low speed cam 38b. The position of the intake-side drive mechanism M _{IN in} the valve chamber 23 is closer to the cylinder 1 than the position shown in FIG. 1, and the operating portions 56a2, 56b2 of the pair of arms 54a, 54b and The contact portions 57a2 and 57b2 occupy positions closer to the first and second intake valve lifters 32a and 32b than those of the above-described embodiment, and the maximum protrusions of the nose portions of the low-speed cams 38a and 38b and the high-speed cams 39a and 39b. Instead, it may protrude radially outward of the intake camshaft 6.

As shown in FIG. 8, also in this intake side drive mechanism M _IN , both low-speed cams
When the first and second rollers 38a and 38b are in sliding contact with the first and second rollers 60a and 60b of the first and second intake valve lifters 32a and 32b, respectively, the operation portion 56a2 and the contact portion 5 near the first intake valve lifter 32a are provided.
Despite the fact that 7a2 protrudes in the radial direction beyond the maximum protruding portion of the nose portion of the low-speed cam 38a and the high-speed cam 39a, it does not come into contact with the first intake valve lifter 32a because it is located in the notch 42a1. Similarly, both high-speed cams in the high-speed rotation range
When the first and second rollers 39a and 39b are in sliding contact with the first and second rollers 60a and 60b of the first and second intake valve lifters 32a and 32b, respectively, the operating portion 56b2 and the contact portion 5 near the second intake valve lifter 32b are provided.
Despite the fact that 7b2 protrudes in the radial direction from the maximum protruding portion of the nose portion of the low speed cam 38b and the high speed cam 39b, it does not come into contact with the second intake valve lifter 32b because it is located in the notch 42b2. Further, the exhaust-side valve train V _EX also uses the exhaust-side drive mechanism M _EX having the same configuration as the intake-side drive mechanism M _IN .

Therefore, according to this embodiment, in addition to the same effects as those of the above-described embodiment, since the reinforcing ribs 70 are provided, the rigidity of the intake (exhaust) cam piece 30 is improved and the intake (exhaust) cam piece 30 is improved. Since the (exhaust) side drive mechanism M _IN is disposed near the cylinder 1, the height of the valve chamber 23 can be reduced, and the effect that the internal combustion engine E can be made compact in the height direction can be obtained. Is done.

In the above embodiment, the first cam portion and the second cam portion of the intake cam piece 30 and the exhaust cam piece 31 are each constituted by a low speed cam and a high speed cam. One of the cam portions is composed of a rest cam and a high-speed cam that keep one of the intake valves or one of the exhaust valves substantially closed, and the one of the intake valves or the one of the exhaust valves in a low-speed rotation range. The valve is closed, the other intake valve and the other exhaust valve are operated by the low speed cam, and in the high speed rotation range,
Both intake valves and both exhaust valves may be operated by a high speed cam. Similarly, in a multi-cylinder internal combustion engine, both cam portions of some cylinders are constituted by a rest cam and a high-speed cam that keep the intake valve and the exhaust valve in a substantially closed state. Both intake valves and exhaust valves of some of the cylinders are closed, the cylinders are stopped, and in the high-speed rotation range, both intake valves and exhaust valves of all cylinders are operated by high-speed cams. You may.

Also, in the above embodiment, one cylinder 1
The pair of intake valves and the pair of exhaust valves were operated by separate cams through separate valve lifters, but both intake or exhaust valves were operated by a single cam through a single valve lifter. It may be activated.

In the above embodiment, the drive pistons of the intake side and exhaust side drive mechanisms occupy two positions. However, the cam portions of the intake and exhaust cam pieces are composed of three cams having different cam profiles. For example, the first hydraulic chamber 55a has a high hydraulic pressure, the second hydraulic chamber 55b has a low hydraulic pressure, and the first hydraulic chamber 55a has a high hydraulic pressure. The hydraulic oil may be controlled such that the second hydraulic chamber 55b is in the second state where the hydraulic pressure is high, and the first hydraulic chamber 55a is in the third state where the hydraulic pressure is low and the second hydraulic chamber 55b is high. Also in this case, the cam that is not in contact with the valve lifter can pass through the notch of the valve lifter, so that the valve operating device can be made compact despite the provision of three cams in the cam portion. Can be.

In the above embodiment, the internal combustion engine E has the intake camshaft 6 and the exhaust camshaft 7, but may be an SOHC type internal combustion engine having a single camshaft. Further, one or three or more intake valves or one or three or more exhaust valves may be provided for each cylinder. Further, the internal combustion engine may be a single cylinder internal combustion engine.

In the above embodiment, the pair of arms 54a and 54b are provided. However, in the intake cam piece 30 and the exhaust cam piece 31, the arm 1a slidingly contacts the cylindrical portion between the first cam portion and the second cam portion. With one arm, both cam pieces 30, 31 can be moved in the axial direction.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view of an internal combustion engine to which an embodiment of the present invention is applied, to which a direct-acting valve train is applied.

FIG. 2 is a partially exploded view of the intake-side valve train.

FIG. 3 is a partial cross-sectional view of the intake cam piece and the intake valve lifter at a low speed position in a plane including the rotation axis of the intake cam shaft and the axis of the valve stem.

FIG. 4 is a partial sectional view similar to FIG. 3 of an intake cam block and an intake valve lifter at a high speed position.

FIG. 5 is a view taken in the direction of arrow V in FIG. 1 and shows a state of an intake cam piece and an intake side driving mechanism at a low speed position.

6 is a view similar to FIG. 5 and shows the state of the intake cam piece and the intake side drive mechanism at the high speed position.

FIG. 7 is another embodiment of the present invention of a direct-acting valve train provided with a valve lifter having a roller.

FIG. 8 is another embodiment of the present invention in which the arrangement of the drive mechanism and the cam piece are different.

[Explanation of symbols]

 1 ... cylinder, 2 ... cylinder block, 3 ... cylinder
Head, 4 ... head cover, 5 ... piston, 6 ... intake cam
Shaft, 7: exhaust camshaft, 8: cam holder, 9: combustion chamber, 10
... intake port, 11 ... exhaust port, 12a, 12b ... intake valve, 13
a: exhaust valve, 14a, 15a: valve guide, 16a, 16b, 17a: valve
Tem, 18a, 18b, 19a ... retainer, 20a, 20b, 21a ... valve
Hey, 22 ... spark plug, 23 ... valve chamber, 24a, 25a ... guide groove, 30 ...
Intake cam piece, 31… Exhaust cam piece, 32a, 32b… Intake valve
Lid, 33a: Exhaust valve lifter, 34: Shaft hole, 35: Groove, 3
6 ... ridge, 37a, 37b ... intake cam part, 38a, 38b ... low speed
, 39a, 39b ... high-speed cam, 40a, 40b ... side, 41a, 41b ...
Cylindrical part, 42a1, 42a2, 42b1, 42b2 ... Notch, 43a, 43b ...
Slipper part, 44a, 44b, 45a ... pin, 50 ... drive piston
, 51a, 51b ... cylinder part, 52a, 52b ... both piston parts,
53 ... connecting part, 54a, 54b ... arm, 55a, 55b ... hydraulic chamber, 56
a1, 56a2, 56b1, 56b2 ... operation unit, 57a1, 57a2, 57b1, 57
b2: contact part, 58a, 58b: opening, 60a, 60b: roller, 61
a, 61b: Support shaft, 62a, 62b: Outer ring, 63a, 63b: Inner ring, 64
a, 64b: Roller, 70: Reinforcing rib, E: Internal combustion engine, L1, L2 ...
Rotation axis, V: Valve train, V_IN... intake side valve gear, V _EX
... Exhaust side valve gear, M_IN... Intake side drive mechanism, M_EX…exhaust
Side drive mechanism.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Junichi Iwamoto 143 Hagadai, Haga-cho, Haga-gun, Tochigi Prefecture F-term (reference) 3G016 AA02 AA08 AA19 BA03 BA06 BA28 BA30 BB04 BB07 CA02 CA11 CA14 CA16 CA29 CA32 DA22 FA12 GA01 3G018 AB07 AB17 BA04 BA24 BA36 CA19 DA01 DA17 FA03 FA06 FA07 GA14 GA22

Claims (4)

[Claims] 1. A cam piece that rotates with a cam shaft,
A plurality of cams having different cam profiles are disposed between a cam piece having a cam portion provided adjacent to the camshaft in the rotation axis direction, and an engine valve for controlling intake or exhaust of the internal combustion engine. The valve lifter and the cam portion,
Switching means for selectively switching a cam that slides on the valve lifter, wherein the engine valve is operated in accordance with a cam profile of the cam on which the engine valve slides. A direct-acting valve train for an internal combustion engine, characterized in that a notch is provided for the cam in the cam that is not in contact with the valve lifter. 2. A cam piece that rotates with a cam shaft,
A plurality of cams having different cam profiles, a cam piece having a cam portion provided in the rotation axis direction of the camshaft; and a valve lifter disposed between the cam portion and an engine valve for controlling intake or exhaust of the internal combustion engine. Switching means for selectively switching a cam that slides on the valve lifter of the cam portion, wherein the engine valve is operated in accordance with a cam profile of the cam that slides on the engine valve. The cam piece is movable in the rotation axis direction with respect to the cam shaft, and the switching means includes an operation member abutting on a side surface of the cam portion in the rotation axis direction, and an operation member via the operation member. A drive member for moving the cam piece in the direction of the rotation axis to switch the cam in sliding contact with the valve lifter, wherein the valve lifter has a relief for the operation member. Direct-acting type valve train for an internal combustion engine, characterized in that a notch portion is provided. 3. The direct-acting valve of claim 1, wherein the notch is formed by a hole that penetrates through the valve lifter and communicates between the inside and the outside. apparatus. 4. The first and second cam portions provided in series in the rotation axis direction on the cam piece.
A cam portion, wherein the engine valves are a first engine valve and a second engine valve provided for the same cylinder, and the valve lifter is disposed between the first engine valve and the first cam portion. A second valve lifter disposed between the second engine valve and the second cam portion, and the same switching means slides on the first valve lifter and the second valve lifter, respectively. The direct-acting valve train of an internal combustion engine according to any one of claims 1 to 3, wherein the contacting cam is selectively switched.