JP2020007946A - Valve gear of engine - Google Patents

Abstract

To provide a valve gear of an engine which can inhibit wear of a valve member which is caused by opening/closing operation of the valve member by a rocker arm.SOLUTION: A valve gear of an engine includes: a connection member 40 which is fixed to a rocker arm 30 and connects the other end side of a shaft part 81 of a valve member 8 with the rocker arm 30 in a relatively swingable manner; and a biasing member 70 which is provided between a cylinder head 2 and the rocker arm 30 and biases the rocker arm 30 in a direction away from the cylinder head 2.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a valve train for an engine that opens and closes intake and exhaust valves (an intake valve and an exhaust valve).

  2. Description of the Related Art An engine (internal combustion engine) mounted on a vehicle such as an automobile includes a valve operating device that opens and closes intake and exhaust valves. A plurality of types of valve operating devices have been put into practical use, and one of them is a device in which a rocker arm is used to open and close an intake / exhaust valve (valve member). Specifically, for example, there is one in which an end face of a shaft portion of a valve member is pressed by a rocker arm to open and close the valve member (for example, see Patent Document 1).

JP-A-2004-137952

  In such a configuration in which the valve member is opened and closed by the rocker arm, the end surface (upper end surface) of the shaft portion of the valve member with which the rocker arm contacts may be worn due to repeated pressing of the valve member by the rocker arm. There is.

  Here, an urging member (valve spring) for urging the valve member in the valve closing direction is generally mounted on the valve member. Therefore, when opening the valve member, the rocker arm needs to press the valve member with a force greater than the urging force of the valve spring. That is, when the valve member is opened, a relatively large pressing force acts on the end surface of the shaft portion of the valve member. This is considered to be one factor that causes the end face of the shaft portion of the valve member to wear.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide an engine valve operating apparatus capable of suppressing wear of a valve member caused by opening and closing a valve member by a rocker arm. .

  One aspect of the present invention that solves the above-mentioned problem is that a rocker arm supported swingably with respect to a cylinder head and an umbrella provided on one end of a shaft in conjunction with the rocker arm are provided with a cylinder. A valve member for opening and closing a valve hole of a head, wherein the valve member is fixed to the rocker arm, and relatively swings the other end of the shaft of the valve member and the rocker arm. And a biasing member provided between the cylinder head and the rocker arm for biasing the rocker arm in a direction away from the cylinder head. In the engine's valve gear.

  Here, the rocker arm includes a penetration portion through which the other end of the shaft portion of the valve member is inserted, and the valve member has a smaller diameter than the other portion at the other end of the shaft portion. The connecting member has a small diameter portion, and the coupling member has an engagement groove portion with which the small diameter portion is engaged in a state where the shaft portion of the valve member is inserted through the insertion portion of the rocker arm. preferable.

  Further, it is preferable that the rocker arm includes a contact portion that is provided to project in a hemispherical shape on the cylinder head side and that the urging member side contacts.

  In addition, it is preferable that the upper surface and the lower surface of the concave portion formed around the small diameter portion of the valve member are formed by curved surfaces having the outside of the valve member protruding.

  As described above, in the engine valve gear according to the present invention, the rocker arm and the valve member are connected via the connecting member, and the rocker arm, not the valve member, is urged by the urging member (valve spring). Therefore, when the rocker arm opens and closes the valve member, no urging force of the urging member acts on the valve member. Therefore, wear of the valve member due to the opening and closing operation of the valve member by the rocker arm can be suppressed.

1 is a diagram illustrating a schematic configuration of an engine on which a valve train according to an embodiment of the present invention is mounted. It is a sectional view showing the valve train concerning one embodiment of the present invention. It is a perspective view explaining composition of a valve train concerning one embodiment of the present invention. It is an exploded view showing the composition of the valve train concerning one embodiment of the present invention. It is a sectional view showing the valve train concerning one embodiment of the present invention.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing an example of an engine on which a valve train according to the present embodiment is mounted, and FIG. 2 is a cross-sectional view showing a main part of the engine. FIG. FIG. 3 is a perspective view illustrating the configuration of a valve train according to one embodiment of the present invention, and FIG. 4 is an exploded view illustrating the configuration of the valve train according to one embodiment of the present invention. FIG. 5 is a sectional view showing a valve train according to one embodiment of the present invention. FIG. 2 is a diagram showing a valve closed state, and FIG. 5 is a diagram showing a valve open state.

  First, an example of an engine (internal combustion engine) on which the valve train according to the present invention is mounted will be briefly described.

  The engine 1 according to the present embodiment shown in FIG. 1 is a multi-cylinder (for example, four-cylinder) gasoline engine of an intake pipe injection type (hereinafter, simply referred to as an engine). An ignition plug 3 is attached to a cylinder head 2 of the engine 1 for each cylinder, and an ignition coil 4 for outputting a high voltage is connected to the ignition plug 3.

  The cylinder head 2 is provided with an intake port 5 for each cylinder, and each intake port 5 is provided with an intake valve (valve member) 8 for opening and closing a valve hole 7 connected to the combustion chamber 6. One end of an intake manifold 9 is connected to each intake port 5. A fuel injection valve 10 is provided in the intake manifold 9. Although not shown, the fuel injection valve 10 is connected to a fuel tank via a fuel pipe and a fuel pump.

  The cylinder head 2 is further provided with an exhaust port 11 for each cylinder, and each exhaust port 11 is provided with an exhaust valve (valve member) 13 that opens and closes a valve hole 12 connected to the combustion chamber 6. One end of an exhaust manifold 16 is connected to each exhaust port 11.

  The intake valve 8 and the exhaust valve 13 of the engine 1 are opened and closed by a valve train 20 according to the present embodiment described below. That is, by opening and closing the intake valve 8 and the exhaust valve 13 by the valve operating device 20, the communication and the cutoff between the intake chamber 5 and the exhaust port 11 and the combustion chamber 6 are performed. Note that the intake valve 8 and the exhaust valve 13 function as a part of the valve train 20.

  Hereinafter, the valve train 20 according to the present embodiment will be described. The valve gear 20 includes an intake valve 8 and an exhaust valve 13 which are valve members. Here, the configuration on the intake valve 8 side will be described, and the exhaust valve 13 side having the same configuration as the intake valve 8 side will be described. The description of the configuration is omitted.

  As shown in FIGS. 2 to 5, the valve operating device 20 includes the intake valve 8 as a valve member, and includes a rocker arm 30 supported swingably with respect to the cylinder head 2. The intake valve 8 and the rocker arm 30 are relatively swingably connected by a clip member (connection member) 40.

  Specifically, first, the intake valve 8 has a shaft portion (valve stem) 81 and an umbrella portion 82 provided at one end of the shaft portion 81, and the umbrella portion 82 opens and closes the valve hole 7 of the intake port 5. It has become so. The shaft portion 81 of the intake valve 8 is inserted into a valve insertion hole 17 formed in the cylinder head 2, and the intake valve 8 is supported by the cylinder head 2 so as to be linearly movable in the valve insertion hole 17.

  On the other end side of the shaft portion 81 of the intake valve 8 (on the side opposite to the umbrella portion 82), a small-diameter portion 84 having a smaller diameter than other portions of the shaft portion 81 is formed. In other words, on the other end side (upper end side) of the shaft portion 81, an engaging recess 85 continuous in the circumferential direction is formed (see FIG. 4), and corresponds to the engaging recess 85 of the shaft portion 81. A portion to be formed is a small diameter portion 84.

  The rocker arm 30 includes a main body member 31 formed by, for example, press working. A roller 32 is rotatably provided at a central portion in the longitudinal direction of the main body member 31 by a support shaft 33. The roller 32 is a member that comes into sliding contact with the cam 61 when the cam 61 provided on the camshaft 60 rotates, and functions as a power point when the rocker arm 30 swings.

  The main body member 31 has one end (support end) 31 a on one longitudinal side supported by the cylinder head 2. The support end portion 31a has an existing structure and will be briefly described. However, the support end portion 31a includes a support member 34 that engages with a concave portion (not shown) provided in the cylinder head 2. The inner surface of the concave portion of the cylinder head 2 is formed in a hemispherical shape, and the outer surface of the support member 34 is formed in a spherical shape. The rocker arm 30 is configured to be swingable with respect to the cylinder head 2 when the support member 34 slides in the recess of the cylinder head 2.

  The shaft 81 of the intake valve 8 is connected to the other end (swinging end) 31 b of the main body member 31 in the longitudinal direction by a clip member 40.

  More specifically, the swing end 31 b of the main body member 31 of the rocker arm 30 is formed with a diameter larger than the outer diameter of the shaft 81 of the intake valve 8, and a through hole (penetration) through which the shaft 81 is inserted. Part) 35 is formed. In a state where the shaft portion 81 of the intake valve (valve member) 8 is inserted into the through hole 35 from one surface side (lower surface side) of the main body member 31, the above-described small diameter portion 84 is connected to the other surface of the main body member 31. (Upper surface). That is, the small-diameter portion 84 is arranged so that the shaft portion 81 is inserted through the through-hole 35 of the main body member 31 and is disposed outside the main body member 31 in a state where the valve hole 7 is closed by the umbrella portion 82. It is provided at a predetermined position of the portion 81.

  In the present embodiment, the clip member 40 has a substantially U-shaped cross section, and is attached to the main body member 31 from the side (the side in the direction orthogonal to the longitudinal direction: the right side) (see FIG. 4), and is fixed to the main body member 31 while being sandwiched in the vertical direction of the main body member 31 (see FIG. 3). In the present embodiment, the clip member 40 is configured to be attachable to the main body member 31 from either the left or right side. Thereby, the degree of freedom in designing the valve train 20 is improved.

  An engagement slit (engagement groove) 42 having a predetermined width is formed in the upper surface 41 of the clip member 40. The engagement slit 42 is formed to have a width larger than the outer diameter of the small-diameter portion 84 of the shaft portion 81 constituting the intake valve 8 and smaller than the outer diameter of the shaft portion 81. An opening 44 is formed in the lower surface 43 of the clip member 40 at a position where a valve spring described later is arranged. Although the shape of the opening 44 is not particularly limited, in the present embodiment, the opening 44 is formed in a slit shape in the same direction as the engagement slit 42.

  Then, the small diameter portion 84 of the shaft portion 81 is engaged with the engagement slit 42 formed in the clip member 40 in a state where the shaft portion 81 of the intake valve 8 is inserted into the through hole 35. The intake valve 8 and the rocker arm 30 are connected (see FIG. 3). In other words, the engagement of the clip member (the edge of the engagement slit 42) 40 with the engagement recess 85 formed around the small diameter portion 84 connects the intake valve 8 and the rocker arm 30 to each other. I have. The shaft portion 81 of the intake valve 8 and the rocker arm 30 connected in this manner can relatively swing.

  In addition, the clip member 40 includes a pair of fixed band portions 45 extending from the tip of the upper surface portion 41 to reach the lower surface portion 43. After attaching the clip member 40 to the main body member 31 of the rocker arm 30, the fixed band portion 45 is bent so as to be in close contact with the surface of the lower surface portion 43 (see FIGS. 3 and 4). Thereby, the clip member 40 is firmly fixed to the main body member 31 of the rocker arm 30. That is, the intake valve 8 and the rocker arm 30 are firmly connected.

  A valve spring (biasing member) 70 for biasing the main body member 31 in a direction away from the cylinder head 2 is provided between the cylinder head 2 and the main body member 31 of the rocker arm 30.

  The valve spring 70 is made of, for example, a coil spring or the like, and one end (lower end) of the valve spring 70 is supported by a protrusion 18 formed on the cylinder head 2. The other end (upper end) of the valve spring 70 is held in contact with the main body member 31 of the rocker arm 30.

  Further, a protruding portion (abutting portion) 36 that protrudes in a hemispherical shape toward the cylinder head 2 side (combustion chamber 6 side) is provided at the swinging end portion 31b of the main body member 31 constituting the rocker arm 30. (See FIG. 2). The valve spring 70, which is a coil spring, is supported by the rocker arm 30 by contacting the protrusion (contact portion) 36. That is, the other end of the valve spring 70 is supported by the rocker arm 30 by fitting the top of the hemispherical projection 36 into the valve spring 70. The above-described insertion hole 35 is provided to penetrate the protrusion 18 and the protrusion (contact portion) 36.

  In the valve operating device 20 having such a configuration, the rocker arm 30 is swung, and the intake valve (valve member) 8 connected to the rocker arm 30 is linearly moved accordingly, whereby the intake port 5 is closed. The valve hole 7 is opened and closed.

  In the present embodiment, the rocker arm 30 swings by the cam 61 rotating about the camshaft 60 sliding on the roller 32 provided on the main body member 31, whereby the intake valve 8 is moved. By linearly moving, the valve hole 7 of the intake port 5 is opened and closed.

  For example, in a closed state in which the valve hole 7 is closed by the intake valve 8 (see FIG. 2), the cam 61 rotates and the roller 32 is pressed (see FIG. 5). Against the urging force (elastic force) of the spring 70, the spring 70 rotates downward about the support end 31a as a fulcrum. Then, with the rotational movement of the rocker arm 30, the intake valve 8 connected to the rocker arm 30 linearly moves downward along the valve insertion hole 17, and the valve hole 7 is opened.

  Thus, in the valve operating device 20 according to the present embodiment, the urging force of the valve spring 70 acts on the main body member 31 of the rocker arm 30 without acting on the intake valve 8. For this reason, the pressing force applied to the intake valve 8 via the clip member 40 during the opening operation of the intake valve 8 is suppressed to be smaller than that of the conventional valve train.

  In the conventional valve train, two forces are applied to the intake valve. One is a force by which the end of the shaft is pressed by the rocker arm, and the other is a force by which the cotter fixed to the shaft is urged by the valve spring.

  On the other hand, in the valve train 20 according to the present embodiment, the force applied to the intake valve 8 is only the force applied to the shaft portion 81 by the rocker arm 30 via the clip member 40. That is, the force biased by the valve spring 70 is not applied to the shaft portion 81. Therefore, the force applied to the intake valve 8 is reduced as compared with the conventional valve gear. Thus, wear of the intake valve 8 due to the opening operation of the intake valve 8 can be suppressed.

  Here, when opening the intake valve 8, the rocker arm 30 rotates around the support end 31 a of the main body member 31 while the intake valve 8 linearly moves along the valve insertion hole 17. For this reason, it is necessary that a predetermined gap is secured between the members at the connection portion between the rocker arm 30 and the intake valve 8.

  Specifically, the width of the engagement slit 42 formed in the clip member 40 is wider than the small-diameter portion 84 so that the rotation of the main body member 31 when the intake valve 8 is opened can be permitted. Has become. That is, a gap is secured between the small-diameter portion 84 and the clip member 40 such that the clip member 40 does not interfere with the small-diameter portion 84 when the main body member 31 rotates (swings).

  Further, in the shaft portion 81 of the intake valve 8, it is preferable that the upper surface portion 85 a and the lower surface portion 85 b of the engagement concave portion 85 have a curved surface with the outside of the shaft portion 81 protruding. That is, it is preferable that the corners between the upper surface 85a and the lower surface 85b of the engagement recess 85 and the outer peripheral surface of the shaft 81 are formed as curved surfaces (see FIG. 4). Accordingly, when the main body member 31 of the rocker arm 30 rotates, the interference between the clip member 40 and the shaft portion 81 in the engagement recess 85 can be more reliably suppressed.

  Similarly, in the main body member 31 of the rocker arm 30, the through hole 35 is formed with such a diameter that the main body member 31 of the rocker arm 30 does not interfere with the shaft portion 81 of the intake valve 8 when opening and closing the intake valve 8. Have been.

  As described above, at the connection portion between the rocker arm 30 and the intake valve 8, a predetermined gap is secured between the members, so that the intake valve 8 and the rocker arm 30 are connected by the clip member 40 as described above. With such a configuration, the intake valve 8 can be satisfactorily opened via the rocker arm 30.

  Further, in this embodiment, the valve spring 70 is supported by the rocker arm 30 by abutting on the protruding portion (contact portion) 36 as described above. However, since it is not fixed to the rocker arm 30, a slight movement in the radial direction is possible. For example, when opening the intake valve 8, the valve spring 70 is slidable on the surface of the protrusion 36 with the rotation of the rocker arm 30. Thereby, the intake valve 8 can be more favorably opened via the rocker arm 30.

  On the other hand, in a valve-open state in which the valve hole 7 is opened (see FIG. 5), when the cam 61 further rotates and the pressing of the roller 32 is released, the rocker arm 30 is elastically (biased) by the valve spring 70. Rotates upward. Accordingly, the intake valve 8 linearly moves upward along the valve insertion hole 17, and the valve hole 7 is closed.

  During the closing operation of the intake valve 8, similarly to the opening operation, the pressing force applied to the intake valve 8 via the clip member 40 is relatively small. Therefore, wear of the intake valve 8 due to the closing operation of the intake valve 8 can also be suppressed.

  Further, in the valve gear 20 according to the present embodiment, the mechanism for opening and closing the intake valve 8 is composed of three parts, the rocker arm 30, the valve spring 70, and the clip member 40. Also, the number of parts has decreased. Since the number of parts is reduced in this way, erroneous assembly of parts during manufacturing of the valve train can be suppressed. In a conventional valve train, a mechanism for opening and closing the intake valve generally includes four parts: a rocker arm, a spring, a retainer, and a cotter.

  Further, since the mechanism for opening and closing the intake valve 8 includes the rocker arm 30, the valve spring 70, and the clip member 40 as described above, the contact between the rocker arm 30 and the shaft portion 81 of the intake valve 8 is achieved. Lubricating oil can be satisfactorily supplied to the portion (the contact portion between the clip member 40 and the shaft portion 81 of the intake valve 8).

  Generally, in a valve gear, lubricating oil is supplied from above the rocker arm, and the lubricating oil is supplied to the contact portion between the rocker arm and the intake valve along the surface of the rocker arm. Has become. In the conventional valve gear, since there is a contact portion with the shaft portion of the intake valve on the lower surface side of the rocker arm, there is a possibility that lubricating oil may not be sufficiently supplied to this contact portion.

  On the other hand, in the valve operating device 20 according to the present embodiment, the shaft portion 81 of the intake valve 8 is connected to the rocker arm 30 while penetrating the rocker arm 30 as described above. That is, the shaft portion 81 is inserted into the through hole 35 from one surface side (lower surface side) of the main body member 31, and the tip end (upper end portion) is located outside the other surface (upper surface) of the main body member 31. are doing. With such a structure, the lubricating oil travels along the surface of the rocker arm 30 and is better at the contact portion between the shaft portion 81 of the intake valve 8 (the contact portion between the clip member 40 and the shaft portion 81). Supplied to

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to said Embodiment.

  For example, in the above-described embodiment, the configuration in which the valve members (the intake valve and the exhaust valve) and the rocker arm main body member are connected using the clip member is exemplified. However, the connection structure between these valve members and the rocker arm is as follows. There is no particular limitation.

  For example, the shaft of the valve member may be swingably connected to the rocker arm by a connecting member using a universal joint or a ball joint. Also in this case, the same operation and effect as the above-described embodiment can be obtained by urging the rocker arm instead of the valve member by the valve spring as the urging member.

  Further, in the above-described embodiment, the present invention has been described by exemplifying the gasoline engine of the intake pipe injection type. However, of course, the present invention is also applicable to other types of gasoline engines of the cylinder injection type and diesel engines. It goes without saying that the present invention can also be used for a valve train of an engine.

DESCRIPTION OF SYMBOLS 1 Engine 2 Cylinder head 3 Spark plug 4 Ignition coil 5 Intake port 6 Combustion chamber 7 Valve hole 8 Intake valve 9 Intake manifold 10 Fuel injection valve 11 Exhaust port 12 Valve hole 13 Exhaust valve 16 Exhaust manifold 17 Valve insertion hole 18 Protrusion 20 Valve operating device 30 Rocker arm 31 Main body member 31a Support end 31b Swing end 32 Roller 33 Support shaft 34 Support member 35 Penetration hole 36 Projection (contact portion)
40 clip member (connection member)
41 Upper surface part 42 Engagement slit 43 Lower surface part 44 Opening part 45 Fixed band part 60 Camshaft 61 Cam 70 Valve spring (biasing member)
81 Shaft part 82 Head part 84 Small diameter part 85 Engagement concave part 85a Upper surface part 85b Lower surface part

Claims (4)

A rocker arm swingably supported with respect to the cylinder head,
A valve member that interlocks with the rocker arm and opens and closes a valve hole of the cylinder head with an umbrella provided at one end of a shaft;
An engine valve train comprising:
A connecting member fixed to the rocker arm and connecting the other end side of the shaft portion of the valve member and the rocker arm so as to be relatively swingable;
An urging member, provided between the cylinder head and the rocker arm, for urging the rocker arm in a direction away from the cylinder head. The valve train of an engine according to claim 1,
The rocker arm includes a penetration portion into which the other end of the shaft portion of the valve member is inserted,
The valve member has a small-diameter portion having a smaller diameter than other portions on the other end side of the shaft portion,
The engine according to claim 1, wherein the connecting member has an engagement groove portion with which the small diameter portion is engaged in a state where the shaft portion of the valve member is inserted through the insertion portion of the rocker arm. Valve device. It is a valve train of the engine of Claim 1 or 2, Comprising:
The valve operating device for an engine according to claim 1, wherein the rocker arm includes a contact portion that is provided on the cylinder head side so as to protrude in a hemispherical shape and is in contact with the biasing member side. It is a valve train of the engine according to any one of claims 1 to 3,
The valve operating device for an engine according to claim 1, wherein an upper surface and a lower surface of a concave portion formed around the small-diameter portion of the valve member are curved surfaces having a convex surface on the outside of the valve member.

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