WO2011125194A1

WO2011125194A1 - Valve actuator for internal combustion engine

Info

Publication number: WO2011125194A1
Application number: PCT/JP2010/056332
Authority: WO
Inventors: 明彦川田; 昭夫木戸岡
Original assignee: トヨタ自動車株式会社
Priority date: 2010-04-07
Filing date: 2010-04-07
Publication date: 2011-10-13
Also published as: CN102892979A; US20130042830A1; EP2557280A4; EP2557280A1; JPWO2011125194A1; JP5299564B2

Abstract

Provided is a valve actuator for an internal combustion engine. The valve actuator comprises a biasing means for biasing a transmission member that transmits the actuating force of a cam to a valve. A support part of the biasing means can be manufactured more easily, and increases in the mass of the internal combustion engine can be restricted by using the valve actuator. The valve actuator comprises a first rocker arm (18), which is disposed between a main cam (14) and a valve (26), for transmitting the actuating force of the main cam (14) to the valve (26). The valve actuator comprises a lost motion mechanism (60) for biasing the first rocker arm (18) in one direction. The valve actuator comprises a holding member (68) for holding the lost motion mechanism (60). The lost motion mechanism (60) is fitted to a spark plug tube (66) with the holding member (68) interposed.

Description

Valve operating device for internal combustion engine

This invention relates to a valve operating apparatus for an internal combustion engine.

Conventionally, for example, Patent Document 1 discloses a valve operating apparatus for an internal combustion engine. This conventional valve gear includes a lost motion mechanism that biases the rocker arm in one direction. More specifically, a cylinder head on which the valve operating device is mounted includes a boss formed by casting around a spark plug insertion cylinder (ignition plug tube). The lost motion mechanism is supported by the boss portion.
The applicant has recognized the following documents including the above-mentioned documents as related to the present invention.

Japanese Unexamined Patent Publication No. 2000-240418 Japanese Unexamined Patent Publication No. 2007-327378 Japanese Unexamined Patent Publication No. 6-280522

When the boss part (support part) for supporting the urging means such as the lost motion mechanism is formed on the upper surface of the cylinder head by casting as in the conventional technique described above, the molten metal once lowered is again directed upward. There is a need to guide. For this reason, when the fluidity of the molten metal is taken into consideration, the shape of the boss portion is poor in manufacturability and has a lot of meat. As a result, the mass of the internal combustion engine increased, which was a factor that deteriorated the fuel efficiency of the vehicle.

The present invention has been made to solve the above-described problems. In a configuration including an urging means for urging a transmission member that transmits an acting force of a cam to a valve, the support portion of the urging means is provided. An object of the present invention is to provide a valve operating device for an internal combustion engine that can realize easy manufacture and suppression of mass increase of the internal combustion engine.

1st invention is a valve operating apparatus of an internal combustion engine,
A transmission member that is interposed between the cam and the valve and transmits the acting force of the cam to the valve;
Biasing means for biasing the transmission member in one direction;
A holding member for holding the biasing means;
With
The biasing means is attached to the spark plug tube via the holding member.

The second invention is the first invention, wherein
The transmission member includes a first rocker arm that swings in synchronization with rotation of the cam,
The biasing means is a means for biasing the first rocker arm toward the cam.

The third invention is the second invention, wherein
The holding member is attached to the spark plug tube in a manner rotatable in the circumferential direction of the spark plug tube,
The valve operating apparatus for the internal combustion engine includes:
An engagement groove formed in one of the urging means and the first rocker arm at a contact portion between the urging means and the first rocker arm;
In the contact portion, a protrusion formed on the other of the biasing means and the first rocker arm, and engaging with the engagement groove;
Is further provided.

Moreover, 4th invention is 2nd or 3rd invention,
The transmission member further includes a second rocker arm capable of pushing the valve,
The valve operating apparatus of the internal combustion engine further includes a switching mechanism capable of switching between a connected state in which the first rocker arm and the second rocker arm are connected and a non-connected state in which the connection is released. ,
The urging means is a lost motion mechanism that urges the first rocker arm so that the first rocker arm is in contact with the cam.

The fifth invention is the first or second invention, wherein
The biasing means is a lash adjuster that has a function of expanding and contracting so as to make the tappet clearance zero, and is arranged so as to support a fulcrum of the transmission member.

According to a sixth invention, in any one of the first to fifth inventions,
The holding member includes a holding portion that covers the body portion of the urging means from the outside, and an attachment portion that is attached to the spark plug tube.

The seventh invention is the sixth invention, wherein
The cross-sectional shape of the holding portion is a shape obtained by enlarging the cross-sectional shape of the urging means.

Further, an eighth invention is any one of the first to seventh inventions,
An end of the urging unit opposite to the end contacting the transmission member is received by a base member to which the spark plug tube is fixed.

According to the first aspect of the present invention, it is not necessary to form the support portion of the biasing means on the upper surface of the base member such as a cylinder head on which the valve operating device is mounted. As a result, since the boss portion (supporting portion) containing the waste meat becomes unnecessary, it is possible to facilitate the manufacture of the supporting portion and reduce the mass of the internal combustion engine. For this reason, the deterioration of the fuel consumption performance of the vehicle due to the increase in mass can be prevented.

According to the second aspect of the invention, in the configuration having the transmission member including the first rocker arm that swings in synchronization with the cam, and the biasing means for biasing the first rocker arm toward the cam, It is possible to facilitate the manufacture of the support portion of the urging means and reduce the mass of the internal combustion engine.

According to the third aspect of the invention, it is possible to accurately position the biasing means with respect to the first rocker arm without increasing the number of parts.

According to the fourth aspect of the present invention, in the valve operating apparatus configured as a lost motion mechanism in which the urging means urges the first rocker arm toward the cam, the manufacturing of the support portion of the lost motion mechanism is facilitated and the internal combustion engine Can be reduced.

According to the fifth aspect of the present invention, in the valve operating apparatus in which the urging means is configured as a lash adjuster that supports the fulcrum of the transmission member, the manufacture of the support portion of the lash adjuster is facilitated and the mass of the internal combustion engine is reduced. be able to.

According to the sixth aspect of the invention, in the configuration including the holding member including the holding portion and the mounting portion, it is possible to facilitate the manufacture of the supporting portion of the urging means and reduce the mass of the internal combustion engine.

According to the seventh invention, since it is not necessary to provide unnecessary protrusions on the holding member, the weight of the holding member can be reduced.

According to the eighth aspect of the invention, the holding member is responsible for only the guide function for guiding the urging means, and the urging force of the urging means is handled by the base member. As a result, since the force acting on the holding member can be reduced, the weight of the holding member can be reduced.

It is a perspective view which shows the structure of the variable valve apparatus of Embodiment 1 of this invention. It is a fragmentary sectional view which shows the structure of the variable valve apparatus shown in FIG. It is a perspective view for demonstrating the characteristic support structure of the lost motion mechanism in Embodiment 1 of this invention. It is a perspective view showing the external shape of the holding member shown in FIG. It is a figure for demonstrating the structure with which a variable valve apparatus is provided in order to position a 1st rocker arm and a lost motion mechanism. It is a figure for demonstrating the effect by the support structure of the lost motion mechanism in Embodiment 1 of this invention. It is sectional drawing which cut | disconnected and represented the lost motion mechanism and the 1st rocker arm in the axial position of the lost motion mechanism seeing from the advancing direction of an engagement groove | channel. It is a figure which shows typically the structure of the valve gear of Embodiment 2 of this invention. It is a figure which shows typically the structure of the other valve operating apparatus applicable to this invention.

Embodiment 1 FIG.
[Basic configuration of valve gear according to Embodiment 1]
The valve operating apparatus for an internal combustion engine according to Embodiment 1 of the present invention is configured as a variable valve operating apparatus capable of switching the operating state of a valve between a valve operating state and a valve closing / stopping state.

FIG. 1 is a perspective view showing a configuration of a variable valve operating apparatus 10 according to a first embodiment of the present invention. FIG. 2 is a partial cross-sectional view showing the configuration of the variable valve apparatus 10 shown in FIG. More specifically, FIG. 1 shows the configuration of a variable valve operating apparatus 10 for a cylinder having an internal combustion engine. 2A is a plane including the axis line of the rocker shaft 22 and the axis lines of the switching pins 36, 38, and 44, and a part of the variable valve operating apparatus 10 (the

rocker arms

18 and 20 and the rocker shaft 22). It is the fragmentary sectional view expressed by cut. In addition, each cylinder of the internal combustion engine is provided with two intake valves and two exhaust valves. The configuration shown in FIGS. 1 and 2 functions as a device that drives two intake valves or two exhaust valves disposed in each cylinder.

The variable valve operating apparatus 10 of the present embodiment includes a camshaft 12. The camshaft 12 is connected to a crankshaft (not shown) by a timing chain or a timing belt, and is configured to rotate at a half speed of the crankshaft. The camshaft 12 is formed with one main cam 14 and one sub cam 16 per cylinder.

The main cam 14 includes an arc-shaped base circle portion 14a coaxial with the camshaft 12, and a nose portion 14b formed so as to bulge a part of the base circle outward in the radial direction. Moreover, in this embodiment, the subcam 16 is comprised as a cam (zero lift cam) which has only a base circle part. Each cylinder of the internal combustion engine is provided with a first rocker arm 18 and a second rocker arm 20 adjacent to each other. The

rocker arms

18 and 20 of each cylinder are supported by a single rocker shaft 22 so as to be rotatable (oscillated).

As shown in FIG. 1, the

rocker arms

18 and 20 are interposed between the

cams

14 and 16 and the valve 26 as transmission members that transmit the acting force of the main cam 14 to the valve 26. A cam roller 28 is rotatably attached to the first rocker arm 18 at a position where it can contact the main cam 14. The first rocker arm 18 is urged by a lost motion mechanism 60 described later so that the cam roller 28 is always in contact with the main cam 14. The configuration relating to the lost motion mechanism 60 is a characteristic part of the present embodiment, and will be described in detail later with reference to FIGS. The first rocker arm 18 configured as described above swings about the rocker shaft 22 as a fulcrum by the cooperation of the acting force of the main cam 14 and the urging force of the lost motion mechanism 60.

1 and 2, the second rocker arm 20 for driving the two valves 26 is integrally configured so as to surround the first rocker arm 18 from both sides. Further, the second rocker arm 20 is provided with a pad 20a at a position where it can come into contact with the sub cam 16 in the base circle section of the main cam 14. The valve 26 is urged in the valve closing direction by a valve spring 30.

(Configuration of switching mechanism)
The variable valve operating apparatus 10 includes a connected state in which the first rocker arm 18 and the second rocker arm 20 are connected (see FIG. 2A) and a disconnected state in which the connection is released (see FIG. 2B). And a switching mechanism 32 for switching between. The variable valve operating apparatus 10 is provided with such a switching mechanism 32 so that the acting force of the main cam 14 is transmitted to the second rocker arm 20 via the first rocker arm 18 (the above-described coupled state); By switching the state in which the acting force is not transmitted to the second rocker arm 20 (the above-mentioned unconnected state), the valve opening characteristic of the valve 26 can be switched between the valve operating state and the valve closing stop state. ing.

As shown in FIG. 2, a first pin hole 34 a concentric with the cam roller 28 is formed in the bush 34 that functions as a support shaft of the cam roller 28, and the first rocker arm 20 has a first pin hole 34 a. Two second pin holes 20bL and 20bR are formed at positions corresponding to the pin holes 34a. A columnar first switching pin 36 is movably inserted into the first pin hole 34a. A cylindrical second switching pin 38 that is in contact with the first switching pin 36 is movably inserted into one (left side in FIG. 1) of the second pin hole 20bL. In the second pin hole 20bL in which the second switching pin 38 is inserted, the end on the opposite side to the first rocker arm 18 is closed by the cap 40. A return spring 42 that urges the second switching pin 38 toward the first rocker arm 18 is disposed inside the second pin hole 20bL. Further, a cylindrical third switching pin 44 that is in contact with the first switching pin 36 is movably inserted into the second pin hole 20bR on the other side (the right side in FIG. 1).

Furthermore, the switching mechanism 32 has a pin driving mechanism for driving the switching pin 36 and the like while resisting the urging force of the return spring 42. More specifically, a link arm 46 having an arm portion 46 a that comes into contact with the third switching pin 44 is disposed on the side of the second rocker arm 20. The link arm 46 is rotatably supported by the rocker shaft 22. Moreover, as shown in FIG. 2, the rocker shaft 22 is formed in a hollow shape. A link shaft 50 is inserted into the rocker shaft 22. The link shaft 50 is a shaft provided to displace the link arm 46 and a link arm (not shown) arranged in another cylinder (not shown) in conjunction with the axial direction of the rocker shaft 22. It is.

As shown in FIGS. 1 and 2, a protrusion 46 b is provided at the tip of the arm portion 46 a of the link arm 46 at a position where it can protrude toward the peripheral surface of the camshaft 12. The camshaft 12 is provided with a guide rail 54 formed as a spiral groove extending in the circumferential direction at a portion facing the protrusion 46b. Furthermore, the switching mechanism 32 includes an electromagnetic solenoid 56 as an actuator that generates a driving force for engaging (inserting) the protrusion 46 b with the guide rail 54. The electromagnetic solenoid 56 is duty-controlled based on a command from an ECU (Electronic Control Unit) 58 for controlling the operating state of the internal combustion engine.

As shown in FIG. 2 (A), the variable valve apparatus 10 of the present embodiment is such that the projection 46b of the link arm 46 is separated from the guide rail 54 in a state where the energization to the electromagnetic solenoid 56 is OFF. The link arm 46 is configured to be positioned at the displacement end Pmax1 under the urging force of the return spring 42. In this state, the first rocker arm 18 and the second rocker arm 20 are connected via the switching pins 36 and 38. As a result, a valve operating state in which the acting force of the main cam 14 is transmitted from the first rocker arm 18 to the both valves 26 via the second rocker arm 20 is achieved.

Further, as shown in FIG. 2B, in the variable valve apparatus 10 of the present embodiment, the link arm 46 pushed by the drive shaft 56a rotates when the electromagnetic solenoid 56 is energized. Thus, the protrusion 46b is engaged with the guide rail 54, and as a result, the link arm 46 is configured to be displaced toward the displacement end Pmax2. In the variable valve operating apparatus 10, while the energization to the electromagnetic solenoid 56 is continued, the protrusion 46 b is separated from the camshaft 12, and the link arm 46 and the drive shaft 56 a of the electromagnetic solenoid are connected. The link arm 46 is configured to be held in a state where the urging force of the return spring 42 is received by engagement. In the state shown in FIG. 2B, the first rocker arm 18 and the second rocker arm 20 are disconnected. As a result, regardless of the rotation of the main cam 14, the second rocker arm 20 is in a stationary state, so that the operation state of the valve 26 is in a closed valve stop state.

As described above, according to the variable valve operating apparatus 10 of the present embodiment, the operation state of the valve 26 is controlled by using the switching pin 36 and the like by switching ON / OFF of the energization to the electromagnetic solenoid 56. It is possible to switch between an operating state and a closed valve stop state. The configuration of the pin drive mechanism is not limited to the above configuration, and for example, the switching pin 36 or the like may be driven using an electric motor or hydraulic pressure.

[Characteristic Configuration of First Embodiment]
FIG. 3 is a perspective view for explaining a characteristic support structure of the lost motion mechanism 60 according to the first embodiment of the present invention. More specifically, FIG. 3 is a partial cross-sectional view showing the components mounted on the cylinder head 62 at the center position of the lost motion mechanism 60.

As shown in FIG. 3, an ignition plug tube 66 for guiding the attachment / detachment of the ignition plug 64 is press-fitted into the central portion of the cylinder head 62 that functions as a base member on which the variable valve apparatus 10 is mounted. An attachment portion 68 a of a holding member 68 that holds the lost motion mechanism 60 is attached to the spark plug tube 66.

FIG. 4 is a perspective view showing the outer shape of the holding member 68 shown in FIG.
As shown in FIGS. 3 and 4, the holding member 68 includes, in addition to the mounting portion 68a, a holding portion 68b that holds the lost motion mechanism 60, and a connecting portion 68c that connects the mounting portion 68a and the holding portion 68b. I have. That is, the lost motion mechanism 60 of this embodiment is attached to the spark plug tube 66 via the holding member 68.

As shown in FIG. 4, the spark plug tube 66 is formed in a cylindrical shape, and the attachment portion 68a fitted into the spark plug tube 66 is also formed in a cylindrical shape with both ends open. Further, the attachment portion 68 a is supported by the spark plug tube 66 in such a manner that the holding member 68 is rotatable in the circumferential direction of the spark plug tube 66.

3, the lost motion mechanism 60 includes a lost motion spring 70 and a lifter 72 interposed between the lost motion spring 70 and the first rocker arm 18. The holding portion 68b of the holding member 68 has a cylindrical shape with both ends open. The lost motion spring 70 and the lifter 72 are accommodated in the holding portion 68b.

The lifter 72 is formed in a cylindrical shape having one end opened and the other end closed. The lost motion spring 70 is housed inside the lifter 72. More specifically, one end of the lost motion spring 70 is in contact with the top 72 a of the closed lifter 72, and the other end is in contact with the cylinder head 62. That is, the lost motion spring 70 is configured to urge the first rocker arm 18 toward the main cam 14 via the top portion 72 a of the lifter 72 while using the cylinder head 62 as a seating surface for receiving the spring load. ing.

In addition, the holding portion 68b is formed so as to cover the side surface of the lifter 72, which is the body portion of the lost motion mechanism 60, and the side surface of the lost motion spring 70 from the outside. The cross-sectional shape (annular circle) of the holding portion 68b cut in the direction perpendicular to the axis of the lost motion mechanism 60 is an enlarged shape of the cross-sectional shape (circular shape) of the lifter 72.

FIG. 5 is a diagram for explaining a configuration provided in the variable valve gear 10 for positioning the first rocker arm 18 and the lost motion mechanism 60. More specifically, FIG. 5 (A) is a view of the first rocker arm 18 from the direction of the portion where the lost motion mechanism 60 contacts, and FIG. 5 (B) shows the lifter 72 from the top 72a side. FIG.

As shown in FIG. 5 (B), an engagement groove 72b is formed in the top portion 72a (the outer surface) of the lifter 72 that comes into contact with the first rocker arm 18. More specifically, the engagement groove 72 b is formed so that the center in the width direction of the groove crosses the outer surface of the top portion 72 a while passing through the axis of the lifter 72.

Further, as shown in FIG. 5A, a protruding pad 18a that engages with the engaging groove 72b is formed in a portion of the first rocker arm 18 that faces the top portion 72a. More specifically, the pad 18 a is formed so as to extend along the moving direction of the first rocker arm 18 when the first rocker arm 18 is viewed from the lifter 72.

FIG. 6 is a diagram for explaining the effect of the support structure of the lost motion mechanism 60 in the first embodiment of the present invention.
As described above, the lost motion mechanism 60 of this embodiment is attached to the spark plug tube 66 via the holding member 68. Thereby, it is not necessary to form the support part of the lost motion mechanism 60 on the upper surface of the cylinder head 62 by casting. As a result, as shown in FIG. 6, the boss portion including the waste is not necessary, so that the support portion can be easily manufactured and the mass of the internal combustion engine can be reduced. For this reason, the deterioration of the fuel consumption performance of the vehicle due to the increase in mass can be prevented. In addition, since processing for large parts such as the cylinder head 62 can be reduced, processing costs can be reduced.

Further, in the variable valve operating apparatus 10 described above, the first rocker arm 18 is disposed between the second rocker arms 20 that push the two valves 26. In other words, the first rocker arm 18 is disposed so as to be sandwiched between the two valves 26 in each cylinder. The spark plug tube 66 is installed at the center of each cylinder. Although not shown here, the two valves 26 are generally equidistant from the center of each cylinder in which the spark plug tube 66 is installed, and the cylinder head is based on the center of each cylinder. 62 is arranged at a symmetrical position in the longitudinal direction. Therefore, as a result, the first rocker arm 18 and the spark plug tube 66 are arranged close to each other as shown in FIG. In the present embodiment, the lost motion mechanism 60 is attached to such a spark plug tube 66 via a holding member 68. For this reason, the connection part 68c of the holding member 68 can be shortened. Thereby, the rigidity of the holding member 68 can be secured satisfactorily, and the weight of the holding member 68 can be reduced.

Also, as described above, one end of the lost motion spring 70 is in contact with the top 72 a of the closed lifter 72, and the other end is in contact with the cylinder head 62. According to such a configuration, the holding portion 68b of the holding member 68 is responsible for only the guide function for guiding the expansion and contraction of the lost motion mechanism 60, and the spring load of the lost motion spring 70 is the cylinder head 62 that is the base member. Will be in charge. As a result, since the force acting on the holding member 68 can be reduced, the weight of the holding member 68 can be reduced.

Further, as described above, the cross-sectional shape of the holding portion 68b cut in the direction perpendicular to the axis of the lost motion mechanism 60 is an enlarged shape of the cross-sectional shape of the lifter 72. Thereby, since it is not necessary to provide an unnecessary protrusion in the holding member 68, the weight of the holding member 68 can be reduced.

FIG. 7 is a cross-sectional view of the lost motion mechanism 60 and the first rocker arm 18 taken along the axial position of the lost motion mechanism 60 as viewed from the advancing direction of the engagement groove 72b.
As described above, the attachment portion 68 a of the holding member 68 is supported by the spark plug tube 66 in such a manner that the holding member 68 is rotatable in the circumferential direction of the spark plug tube 66. Then, as shown in FIG. 7, the engagement groove 72 b formed on the lifter 72 and the pad 18 a formed on the first rocker arm 18 engage with each other, thereby positioning the lifter 72 with respect to the first rocker arm 18. Done.

In the case where the lost motion mechanism 60 is held by a separate holding member 68 from the cylinder head 62, unlike the above-described configuration, when the configuration for fixing the rotation position of the mounting portion with respect to the spark plug tube is employed, Such a problem arises. That is, when the contact point between the first rocker arm and the lost motion mechanism deviates from the center of the lost motion mechanism, a force that pushes the lost motion spring in the radial direction acts on the holding member. Therefore, it is important to accurately position the lost motion mechanism with respect to the first rocker arm. For this reason, if the structure which fixes the rotation position of the attaching part with respect to a spark plug tube is employ | adopted, it will be necessary to assemble | attach the position of the lost motion mechanism with respect to a 1st rocker arm accurately. For this purpose, high processing and assembly accuracy are required for the spark plug tube press-fitted into the cylinder head, and the number of work steps required for the above process increases.

On the other hand, according to the configuration of the present embodiment, the engaging portion 72a of the holding member 68 is configured to be rotatable with respect to the spark plug tube 66, and the engaging groove 72b formed in the lifter 72 and the first rocker arm are configured. By engaging with the pad 18a formed on 18, the lost motion mechanism 60 can be accurately positioned with respect to the first rocker arm 18 without increasing the number of parts.

In the first embodiment described above, the main cam 14 is the “cam” in the first invention, the first rocker arm 18 is the “transmission member” in the first invention, and the lost motion mechanism 60 is the It corresponds to the “biasing means” in the first invention.
The pad 18a formed on the first rocker arm 18 corresponds to the “projection” in the third aspect of the invention.
The cylinder head 62 corresponds to the “base member” in the eighth invention.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 8 is a diagram schematically showing the configuration of the valve gear 80 according to Embodiment 2 of the present invention. In FIG. 8, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted or simplified.

8 includes a rocker arm 84 as a transmission member interposed between the cam 82 and the valve 26. The valve operating device 80 shown in FIG. More specifically, the end of the valve 26 is in contact with one end of the rocker arm 84, and a cam roller 86 is installed at the center of the rocker arm 84. Further, the other end of the rocker arm 84 is supported by a lash adjuster 88. With such a configuration, the rocker arm 84 can rotate with the end portion (the other end) supported by the lash adjuster 88 as a fulcrum. The lash adjuster 88 has a function of expanding and contracting so that the tappet clearance is zero.

As shown in FIG. 8, the spark plug tube 66 is press-fitted into the cylinder head 62 also in this embodiment. The lash adjuster 88 is attached to the spark plug tube 66 via a holding member 90. The holding member 90 includes an attachment portion 90a attached to the spark plug tube 66, a holding portion 90b that holds the lash adjuster 88, and a connecting portion 90c that connects the attachment portion 90a and the holding portion 90b.

One end of the lash adjuster 88 is in contact with the other end of the rocker arm 84 as described above. The other end of the lash adjuster 88 is in contact with the cylinder head 62. That is, the lash adjuster 88 is configured to be able to urge the rocker arm 84 toward the cam 82 while using the cylinder head 62 as a seating surface that receives a load acting on the lash adjuster 88 via the rocker arm 84. Yes.

In addition, in the present embodiment as well, the holding portion 90b is formed so as to cover the side surface of the lash adjuster 88, which is the body portion of the lash adjuster 88, from the outside. The cross-sectional shape (annular circle) of the holding portion 90b cut in the direction perpendicular to the axis of the lash adjuster 88 is an enlarged shape of the cross-sectional shape (circular shape) of the lash adjuster 88.

Furthermore, in this embodiment, the protrusion 88 a of the lash adjuster 88 that functions as a fulcrum of the rocker arm 84 is configured to engage with an engagement groove 84 a provided at the other end of the rocker arm 84.

As described above, in this embodiment, the lash adjuster 88 that is used as a biasing unit that biases the rocker arm 84 that is a transmission member is attached to the spark plug tube 66 via the holding member 90. . Thereby, it is not necessary to form the support portion of the lash adjuster 88 on the upper surface of the cylinder head 62 by casting. As a result, the need for the boss portion including the sacrificial meat is eliminated, so that the support portion can be easily manufactured and the mass of the internal combustion engine can be reduced. For this reason, the deterioration of the fuel consumption performance of the vehicle due to the increase in mass can be prevented. In addition, the same effects as those of the first embodiment described above can be obtained.

In the second embodiment described above, the rocker arm 84 corresponds to the “transmission member” in the first invention, and the lash adjuster 88 corresponds to the “biasing means” in the first invention.

By the way, in Embodiment 1 mentioned above, it demonstrated taking the case of the structure in which the lost motion mechanism 60 which urges | biases the 1st rocker arm 18 was attached to the spark plug tube 66 via the holding member 68. However, the configuration of the valve operating apparatus for the internal combustion engine to which the present invention is applicable is not limited to the above, and may be, for example, a configuration as shown in FIG.

FIG. 9 is a diagram schematically showing the configuration of another valve gear applicable to the present invention. In FIG. 9, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted or simplified.
The variable valve operating apparatus 100 shown in FIG. 9 includes a first rocker arm 102 similar to the first rocker arm 18 as a transmission member interposed between the main cam 14 and the valve 26 (not shown in FIG. 9). I have. More specifically, one end of the first rocker arm 102 is rotatably supported by the rocker shaft 22, and a cam roller 104 is installed at the center of the first rocker arm 102. Further, a lost motion arm 106 formed in an L shape is fixed to the other end of the first rocker arm 102.

Furthermore, the variable valve operating apparatus 100 includes a lost motion mechanism 108 that urges the first rocker arm 102 toward the main cam 14 via the lost motion arm 106. The lost motion mechanism 108 includes a lost motion spring 110 and a lifter 112 interposed between the lost motion spring 110 and the lost motion arm 106.

Also in the configuration shown in FIG. 9, the spark plug tube 66 is press-fitted into the cylinder head 62. The lost motion mechanism 108 is attached to the spark plug tube 66 via a holding member 114. The holding member 114 includes an attachment portion 114 a attached to the spark plug tube 66 and a holding portion 114 b that holds the lost motion mechanism 108. In addition, in the holding member 114 shown in FIG. 9, the connection part is not provided, but the holding part 114b is attached to the attachment part 114a in the perpendicular direction.

Further, as shown in FIG. 9B, an engagement groove 112 b that engages with a pad 106 a provided on the lost motion arm 106 is formed on the top 112 a of the lifter 112. Even with the configuration shown in FIG. 9 described above, the same effects as those of the first embodiment described above can be obtained.

In the first and second embodiments described above, the example in which the sub cam 16 is configured as a zero lift cam has been described. However, the sub cam in the present invention is not limited to the zero lift cam. That is, for example, in the case of the configuration of the variable valve apparatus 10 described above, a secondary cam provided with a nose portion that allows a lift smaller than that of the main cam 14 may be used. According to the configuration including such a secondary cam, the lift amount (and / or operating angle) of the valve can be switched in two stages by the main cam and the secondary cam.

In the above-described first embodiment, the variable valve apparatus 10 has been described as an example. However, the valve gear that is the subject of the present invention is not limited to that configured as a variable valve gear as described above in the second embodiment. That is, it may be provided with a holding member that holds a biasing means that biases the transmission member interposed between the cam and the valve.

Further, in the first and second embodiments described above, the first rocker arm 18 and the like have been described as examples of biasing targets by the lost motion mechanism 60 and the lash adjuster 88 that function as biasing means. However, the transmission member in the present invention is not limited to the rocker arm. In other words, it may be anything that is interposed between the cam and the valve and transmits the acting force of the cam to the valve.

Further, in the first embodiment described above, the engagement groove 72b is formed in the top portion 72a of the lifter 72 of the lost motion mechanism 60, and the engagement groove 72b is formed at a portion facing the lifter 72 in the first rocker arm 18. An example in which the engaging pad (projection) 18a is formed has been described. However, the present invention is not limited to this. For example, a protrusion such as a pad is formed on the top portion 72a side of the lifter 72 that is a biasing means, and the first rocker arm 18 side that is a transmission member is formed. An engagement groove may be formed.

In the first embodiment described above, the lost motion mechanism 60 that urges the first rocker arm 18 toward the main cam 14 in the pushing direction has been described as an example. However, the configuration of the urging means in the present invention is not limited to this, and for example, an urging force may be generated in a direction in which the transmission member such as the first rocker arm 18 is drawn.

10, 100 Variable valve gear 12 Cam shaft 14 Main cam 14a Base circular portion 14b Nose portion 16

Sub cam

18, 102 First rocker arm 18a Pad 20 Second rocker arm 20bL, 20bR Second pin hole 22 Rocker shaft 26

Valve

28 , 86, 104 Cam roller 32 Switching mechanism 34a First pin hole 36 First switching pin 38 Second switching pin 42 Return spring 44 Third switching pin 46 Link arm 50 Link shaft 54 Guide rail 56 Electromagnetic solenoid 58 ECU (Electronic Control Unit)
60, 108 Lost motion mechanism 62 Cylinder head 64 Spark plug 66

Spark plug tube

68, 90, 114

Holding member

68a, 90a,

114a Mounting portion

68b, 90b,

114b Holding portion

68c,

90c Connecting portion

70, 110

Lost motion spring

72, 112

Lifter

72b, 84a, 112b Engaging groove 80 Valve operating device 82 Cam 84 Rocker arm 88 Rush adjuster 88a Projection 106 Lost motion arm 106a Pad Pmax1 Displacement end Pmax2 Displacement end

Claims

A transmission member that is interposed between the cam and the valve and transmits the acting force of the cam to the valve;
Biasing means for biasing the transmission member in one direction;
A holding member for holding the biasing means;
With
The valve operating apparatus for an internal combustion engine, wherein the urging means is attached to the spark plug tube via the holding member.
The transmission member includes a first rocker arm that swings in synchronization with rotation of the cam,
2. The valve operating apparatus for an internal combustion engine according to claim 1, wherein the urging means is means for urging the first rocker arm toward the cam.
The holding member is attached to the spark plug tube in a manner rotatable in the circumferential direction of the spark plug tube,
The valve operating apparatus for the internal combustion engine includes:
An engagement groove formed in one of the urging means and the first rocker arm at a contact portion between the urging means and the first rocker arm;
In the contact portion, a protrusion formed on the other of the urging means and the first rocker arm and engaged with the engagement groove;
The valve operating apparatus for an internal combustion engine according to claim 2, further comprising:
The transmission member further includes a second rocker arm capable of pushing the valve,
The valve operating apparatus of the internal combustion engine further includes a switching mechanism capable of switching between a connected state in which the first rocker arm and the second rocker arm are connected and a non-connected state in which the connection is released. ,
4. The internal combustion engine according to claim 2, wherein the biasing means is a lost motion mechanism that biases the first rocker arm so that the first rocker arm is in contact with the cam. 5. Engine valve gear.
3. The internal combustion engine according to claim 1, wherein the biasing means is a lash adjuster that has a function of expanding and contracting so that a tappet clearance is zero, and is arranged to support a fulcrum of the transmission member. Engine valve gear.
6. The internal combustion engine according to claim 1, wherein the holding member includes a holding portion that covers the body portion of the biasing unit from the outside, and an attachment portion that is attached to the spark plug tube. Engine valve gear.
7. The valve operating apparatus for an internal combustion engine according to claim 6, wherein the cross-sectional shape of the holding portion is a shape obtained by enlarging the cross-sectional shape of the biasing means.
8. The end of the biasing means opposite to the end contacting the transmission member is received by a base member to which the spark plug tube is fixed. A valve operating apparatus for an internal combustion engine according to the item.