JP2008190350A - Forced opening/closing device for direct driven valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forced opening/closing device for a direct driven valve, for an engine capable of operating at higher revolution, having a simple structure and a reduced parts-count. <P>SOLUTION: A valve-opening cam and a valve-closing cam are provided to a camshaft rotated by the engine. A valve-opening contact-plate is provided on the side of the valve which is slidingly interlocked with the valve-opening cam. On the other side thereof, a valve-closing contact-plate is provided which is slidingly interlocked with the valve-closing cam. The valve-opening contact-plate and the valve-closing contact plate are connected by a coupling member, a valve-installation part is provided below the valve-opening contact plate, and the valve is placed in the part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a valve forced opening / closing device, and more particularly to a valve forced opening / closing device that directly opens and closes a valve by a camshaft cam rotated by an engine.

  2. Description of the Related Art Conventionally, an internal combustion engine, particularly an engine using a poppet valve, is provided with an intake valve for performing intake to the combustion chamber and an exhaust valve for performing exhaust from the combustion chamber. When the valve mechanism that drives these valves is opened, a cam for opening is provided on the camshaft that rotates in synchronization with the engine rotation, and it is driven directly by the cam or through the rocker arm, but when it is closed In general, a valve closing method using a spring is known.

As for valve closing, there is a forced opening / closing system in which the valve is forcibly closed via a rocker arm by a valve closing cam. (For example, see Patent Document 1 and Patent Document 2.)
JP-A-1-247707 JP-A-1-247706

  In general, when demanding higher performance of a four-cycle engine, it is said that if the engine displacement is the same, the output of the engine increases as the engine speed is increased. As the valve operating mechanism for this purpose, a direct drive type that opens by pressing down a tappet attached to the valve stem directly by the valve opening cam of the camshaft and closes by a spring is selected.

However, when the engine is driven at a high speed, the valve is opened and closed at a short cycle, and the valve may not be closed correctly due to the surging of the spring. there were.
Also, this spring loses engine output because a spring with higher repulsive force is used for an engine that rotates at a higher speed.

  As a valve forced opening / closing device that does not use a valve spring, a camshaft is provided on the camshaft. When opening the valve, the tappet attached to the valve stem is pushed down directly by the valve opening cam. When the valve is opened and then closed, the valve retainer is pulled up and closed by the valve closing cam through the valve closing rocker arm. However, such a valve forced opening / closing device has a drawback that the number of parts of the valve forced opening / closing device is increased, the structure of the valve forced opening / closing device is complicated, and costs are increased.

  Further, in a valve forced opening / closing device in which two valves are connected by a valve forced drive body of an internal combustion engine having two intake valves or exhaust valves for one cylinder, the valve forced drive body becomes heavy and at high speed. It is unsuitable as a component that reciprocates.

  The present invention has been made in view of these circumstances. When the engine is rotated at a high speed, many components such as a valve, a cam, a rocker arm, and a valve spring move at a high speed, resulting in a very large output loss. Therefore, the object is to provide a direct drive valve forced opening and closing device for an engine that can be rotated at a higher speed than before by eliminating the rocker arm and valve spring, reducing the number of parts, and making it a simple structure. .

  In order to achieve the above object, according to the first aspect of the present invention, the camshaft rotated by the engine is provided with a valve-opening cam and a valve-closing cam, and the valve side of the cam is in sliding contact with the valve-opening cam. A valve contact plate is provided, and on the opposite side, a valve close contact plate that is slidably linked to the valve close cam is provided. The valve open contact plate and the valve close contact plate are connected by a connecting member, and the valve open contact plate Install the valve mounting part below and install the valve.

  Further, the invention according to claim 2 is provided with a plurality of cams for opening or closing the valve of the direct drive valve forced opening / closing device according to claim 1. For example, when one valve opening cam and two valve closing cams are used, the center of gravity when contacting the cam and the contact plate is centered compared to when one valve opening cam and one valve closing cam are used. Balance.

  Further, by passing a connecting member that connects the valve opening contact plate and the valve closing contact plate between the valve opening cam and the valve closing cam, it is possible to obtain a more compact and high-strength direct drive valve forced opening / closing device. .

  In the invention according to claim 1, the valve opening valve is opened by the valve opening contact plate that is slidably linked to the valve opening cam provided on the camshaft rotated by the engine, and the valve closing valve is slidably linked to the valve closing cam. By closing the valve with the contact plate, the valve can always move in conjunction with the valve opening cam and the valve closing cam. This eliminates the need for rocker arms and valve springs that have been used in the past, resulting in a compact and simple structure. An engine with higher rotation and higher output can be produced. Further, since the driving resistance is small, the fuel consumption is improved. Further, even a two-cycle engine, which has been considered difficult in the past and in which the crankshaft and the camshaft rotate at the same rotation, can be used because the camshaft can be rotated at a high speed. The present invention can be used with either an intake valve or an exhaust valve.

  In the invention according to claim 2, when a plurality of valve opening cams or valve closing cams are provided, for example, when one valve opening cam and two valve closing cams are provided, or two valve opening cams are provided. When the number of the valve closing cams is one, the center of gravity at the time of driving the valve unit comes to the center as compared with the case where one valve opening cam and one valve closing cam are provided.

  In the invention according to claim 3, the connecting member that connects the valve opening contact plate and the valve closing contact plate is passed between the valve opening cam and the valve closing cam, so that it is excellent in strength, and is smaller and lighter. can do.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a side view showing a direct drive valve forced opening / closing device (embodiment of claim 1) of an internal combustion engine according to the present invention. A valve opening cam 1 and a valve closing cam 2 are formed on the cam shaft 3 so as to be orthogonal to the axis. A valve opening contact plate 6 slidably linked to the valve opening cam 1 and a valve closing contact plate 7 slidably linked to the valve closing cam 2 are provided, and the valve opening contact plate 6 and valve closing contact plate 7 are provided. Are connected by a connecting member 8, and a valve mounting portion 5 is provided under the valve opening contact plate 6 so as to hold the valve 4 by the valve opening contact plate 6, and the valve 4 is attached thereto. The valve unit 9 is a state where the valve opening contact plate 6, the valve closing contact plate 7, the connecting portion 8, the valve mounting portion 5, and the valve 4 are assembled.

  Next, the operation will be described. FIG. 3 is a side view of a schematic explanation of the direct drive valve forced opening / closing device showing the operating state of claim 1 of the present invention. The valve-opening cam 1 and the valve-closing cam 2 formed on the camshaft 3 rotate in synchronization with the engine rotation, so that the valve-opening contact plate 6 and the valve-closing contact plate 7 are at the contact point a. The valve closing cam 2 and the valve closing contact plate 7 are always in sliding contact with each other at the contact point b to move the valve unit 9 so that the valve 4 always moves from the low rotation to the high rotation. By following, the valve 4 can be opened and closed accurately.

  Further, FIG. 4A is a cross-sectional view of a direct drive valve forced opening / closing device of an embodiment in which a plurality of valve closing cams 2 according to claim 2 are provided. The valve opening cam 1 formed on the shaft is formed on the camshaft 3 of the embodiment of the first aspect, and the valve closing cams 2 are formed on both sides thereof. A valve opening contact plate 6 slidably linked to the valve opening cam 1 and a valve closing contact plate 7 slidably linked to the valve closing cams 2 on both sides are provided, and the valve opening contact plate 6 and the valve closing contact are provided. The plate 7 is connected by a connecting member 8, and the valve mounting portion 5 is provided under the valve opening contact plate 6 so as to hold the valve 4 by the valve opening contact plate 6, and the valve 4 is attached thereto.

  FIG. 4B is a cross-sectional view showing the embodiment of claim 2 in which the positions of the valve opening cam 1 and the valve closing cam 2 of FIG. . In both forms, the center of gravity when the valve unit 9 is driven is at the center, so the effect is the same but it can be driven stably at high speed.

  FIG. 5 is a cross-sectional view showing a direct drive valve forced opening / closing device of an embodiment of claim 3. 5A, the valve opening cam 1 and the valve closing cam 2 are formed on the camshaft 3 so as to be orthogonal to the axis as in the first aspect. A valve opening contact plate 6 slidably linked to the valve opening cam 1 and a valve closing contact plate 7 slidably linked to the valve closing cam 2 are provided, and the valve opening contact plate 6 and valve closing contact plate 7 are provided. Are connected by a connecting member 8 so as to pass between the valve opening cam 1 and the valve closing cam 2, and the valve 4 is pressed by the valve opening contact plate 6 below the valve opening contact plate 6. A valve attachment portion 5 is provided, and the valve 4 is attached thereto.

FIG. 6 is a cross-sectional view showing an embodiment of claim 3 when the valve opening cam 2 of claim 2 is made plural, and FIG. 7 is a side view of the embodiment of claim 3. The valve opening cam 1 formed so as to be orthogonal to the axis 3 is formed, and the valve closing cam 2 is formed on both sides thereof. A valve opening contact plate 6 slidably linked to the valve opening cam 1 and a valve closing contact plate 7 slidably linked to the valve closing cams 2 on both sides are provided, and the connecting portion 9 is connected to the valve opening cam 1 and both sides. The valve-opening contact plate 6 and the valve-closing contact plate 7 are connected to each other, and at this time, the connecting member 8 and the valve-closing contact plate 7 are fixed with bolts or fixing pins 10 to be disassembled. It becomes easy to do. A valve mounting portion 5 is provided under the valve opening contact plate 6 so as to hold the valve 4 by the valve opening contact plate 6, and the valve 4 is attached thereto. Even if the positions of the valve opening cam 1 and the valve closing cam 2 are reversed, the effect is the same. (Not shown)
Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and the present invention can be used with either an intake valve or an exhaust valve.

  The direct drive valve forced opening / closing device of the present invention is most suitable for all overhead valve internal combustion engines.

1 is a side view of a direct drive valve forced opening / closing device showing an embodiment of claim 1 of the present invention; FIG. FIG. 3 is a cross-sectional view of the direct drive valve forced opening / closing device according to the first embodiment of the present invention, cut along C-C ″ in FIG. 1 and viewed from the right side. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a schematic explanation of a direct drive valve forced opening / closing device showing an operation state of claim 1 of the present invention; FIG. 2 is a cross-sectional view of the direct drive valve forced opening / closing device as viewed from the front side, showing an embodiment in which A is two valve closing cams and B is two valve opening cams. It is sectional drawing seen from the front of the direct drive valve forced opening / closing apparatus which shows the example implemented in Claim 3 of Claim 1 of this invention. It is sectional drawing seen from the front of the direct drive valve forced opening / closing apparatus which shows the example implemented in Claim 3 in Claim 2 of this invention. It is a side view of the direct drive valve forced opening / closing apparatus which shows the Example of Claim 3 of this invention.

Explanation of symbols

1 Cam for valve opening 2 Cam for valve closing 3 Camshaft 4 Valve
5 Valve mounting portion 6 Valve-opening contact plate 7 Valve-closing contact plate 8 Connecting member
9 Valve unit 10 Fixing pin 11 Intake pipe

Claims (3)

  A camshaft rotated by the engine is provided with a valve-opening cam and a valve-closing cam, a valve-opening contact plate that is slidably linked to the valve-opening cam is provided on the valve side, and a valve-closing cam is slid on the opposite side. A valve closing contact plate that is connected and linked is connected, the valve opening contact plate and the valve closing contact plate are connected by a connecting member, and a valve mounting portion is provided under the valve opening contact plate. Direct drive valve forced opening and closing device.   A direct drive valve forced opening / closing device comprising a plurality of cams of either the valve opening cam or the valve closing cam according to claim 1.   A direct drive valve forced opening / closing device in which the connecting member according to claim 1 and 2 is connected between a valve opening cam and a valve closing cam.

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