JP2009156110A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein, if a driving mechanism of a control shaft for controlling the lift amount of a valve is immersed in lubricating oil filled in a housing, a case may occur in which the driving mechanism is not smoothly operated with a lump, sludge or the like in lubricating oil in a valve lift variable type valve system built in an internal combustion engine. <P>SOLUTION: In the internal combustion engine having a valve lift variable type valve system, a gear device and an electric motor for driving a valve lift variable operation shaft of the valve lift variable type valve system are provided. The movement of the gear device is suppressed by a suppression plate for suppressing the reaction force from the valve lift variable operation shaft. The electric motor is fitted to an outer surface of a cylinder head cover with its output shaft being downwardly directed and substantially orthogonal to the valve lift variable operation shaft. The suppression plate has an oil passage for guiding lubricating oil dripped on its upper surface to the gear device. The cylinder head cover has an oil passage for guiding lubricating oil to be fed from the cylinder head so as to be dripped in the oil passage of the suppression plate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an internal combustion engine provided with a variable valve lift valve gear.

  2. Description of the Related Art Conventionally, in an internal combustion engine mounted on a vehicle such as an automobile, at least one of an intake valve and an exhaust valve is opened and closed by a valve operating device in synchronization with the rotation of a crankshaft. In recent years, in order to improve fuel economy, output, etc., the valve lift variable valve that can change the lift amount of the valve when opening the valve as desired during operation of the internal combustion engine. The device is known.

  The variable valve lift type valve operating apparatus described in Patent Document 1 includes a variable mechanism that variably controls the operation characteristics of an intake valve, for example, by rotating a control shaft in accordance with an operating state of the internal combustion engine, and a drive that rotationally controls the control shaft. And a drive mechanism linked to the output shaft of the electric motor and a screw transmission means for rotating the control shaft. Between the output shaft of the electric motor and the screw transmission means, both shafts are provided. A connecting mechanism that allows movement in the direction and connects the rotational torque from the output shaft to the screw transmitting means is provided.

In such a configuration, the screw transmission means may generate heat during operation, and is thus immersed in the lubricating oil. Specifically, the screw transmission means is housed in a housing having a cylindrical portion, a bulging portion, and a side wall, and the housing is liquid-tightly closed and filled with lubricating oil.
Japanese Patent Laid-Open No. 2004-76620

  However, in such a configuration, the lubricating oil circulates in the housing, but does not go out and is not filtered. As a result, the lubricating oil may be denatured and a lump of lubricating oil may be generated or sludge may accumulate. Such a lump of lubricating oil or sludge may be caught in the screw transmission means or sandwiched between the coupling mechanisms, and the smooth operation of the drive mechanism may be hindered.

  Therefore, the present invention aims to eliminate such problems.

  That is, the internal combustion engine of the present invention is an internal combustion engine comprising a valve lift variable valve operating device for at least one of an intake valve and an exhaust valve between an upper portion of a cylinder head and a cylinder head cover. In the variable valve lift type valve gear, the cam provided on the camshaft rotating in conjunction with the crankshaft rotates while contacting the one end of the swinging arm, so that the swinging arm is operated to change the valve lift. The valve swings around the contact point with the fulcrum provided on the valve, and opens and closes the valve that contacts the other end of the swinging arm by swinging the swinging arm. The valve lift variable operation is controlled by a gear device that is restrained from moving by a suppression plate that suppresses reaction force from the valve lift variable operation shaft and a motor that drives the gear device. Is configured so that the contact point of the fulcrum portion with the swing arm can be moved in the longitudinal direction of the swing arm. So that the restraining plate is provided with an oil passage that guides the lubricating oil dropped on the upper surface thereof to the gear device, and the cylinder head cover is dripped onto the oil passage of the restraining plate. An oil passage for guiding lubricating oil supplied from the cylinder head is provided.

  According to such a configuration, the lubricating oil drops from the cylinder head through the oil passage of the cylinder head cover to the suppression plate. Thereafter, the lubricating oil flows through the oil passage and is guided to the gear device. That is, the lubricating oil is constantly circulated when the engine is operating. Therefore, it is possible to prevent the lubricating oil from stagnating and solidifying, or sludge accumulation. In addition, the number of parts can be reduced by providing an oil passage in the cylinder head cover.

  As described above, the present invention is configured such that the lubricating oil can be circulated at all times, so that the lubricating oil can be prevented from stagnating and solidifying, and sludge can be prevented from accumulating. By providing an oil passage in the head cover, the number of parts can be reduced.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  An internal combustion engine, that is, an engine 100 according to an embodiment described below is, for example, a four-cylinder engine. In FIG. 1, the structure around the intake valve 1 of one cylinder is shown. The engine 100 includes a valve lift variable valve gear 3 between the upper part of the cylinder head 2 and the cylinder head cover 50. In this embodiment, the variable valve lift type valve gear 3 is provided for both the intake valve 1 and the exhaust valve (not shown), but since it has the same structure, only the one for the intake valve 1 is provided. This is illustrated and described. The variable valve lift type valve gear 3 may be attached to at least one of the intake valve 1 and the exhaust valve.

  In this embodiment, the cylinder head cover 50 includes a first cylinder head cover (not shown) that covers substantially the entire area of the cylinder head 2 and a cylinder head 2 in which a driving means 51 of a valve lift variable valve gear 3 described later is disposed. It is divided into a second cylinder head cover 52 that covers this part. As shown in FIGS. 2 and 3, an oil passage 63 described later is formed inside the front wall 52 a and the upper wall 52 b of the second cylinder head cover 52. The upper wall 52b is provided with an attachment hole 52c for attaching the electric motor 53 constituting the driving means 51. In this embodiment, since the variable valve lift type valve operating device is also attached to the exhaust valve, two attachment holes 52c are provided in a close state.

  The variable valve lift type valve gear 3 includes a swing arm 6 in which a cam 5 provided on a cam shaft 4 that rotates in conjunction with a crank shaft contacts one end, and a fulcrum roller 7 that is a fulcrum that contacts the swing arm 6. A variable valve lift operating shaft (hereinafter referred to as an operating shaft) 8, a compression spring 9 that biases the swing arm 6 toward the cam 5, a rocker arm 10 that contacts the lower end of the swing arm 6, and The driving means 51 for driving the operation shaft 8 is mainly configured. The cam 5, the swing arm 6, the fulcrum roller, and the rocker arm 10 are paired with the intake valve 1 in each cylinder.

  As shown in FIG. 5, the drive means 51 is a gear that is provided between the electric motor 53 and the output shaft 53 a of the electric motor 53 and the swing arm 6 and transmits the driving force of the electric motor 53 to the operation shaft 8. Device 54. The electric motor 53 is attached to the outer surface of the second cylinder head cover 52 with the output shaft 53a facing downward, that is, toward the cylinder head 2 side. In this embodiment, since both the intake valve 1 and the exhaust valve can control the lift amount, the two electric motors 53 are attached in close proximity.

  The gear device 54 is attached to the cylinder head 2, and includes a worm gear 55 attached to the output shaft 53 a of the electric motor 53, a worm wheel 56 attached to the operation shaft 8, a rotating shaft 57 that fixes the worm gear 55, and rotation. A pair of bearings 58 that rotatably support the shaft 57, a suppression plate 59 that prohibits the movement of the rotating shaft 57 toward the electric motor 53, and a connecting member that connects the output shaft 53a of the electric motor 53 and the rotating shaft 57. 60.

  The worm gear 55 of the gear device 54 is attached to a rotating shaft 57 that is arranged on the lower side of the output shaft 53 a of the electric motor 53 so as to have the same axis line in correspondence with the position of the worm wheel 56. Since the worm wheel 56 does not need to rotate the operation shaft 8 360 degrees, the worm wheel 56 has a fan shape having teeth in an angle range corresponding to the rotation range of the operation shaft 8. The operating range of the worm wheel 56 is indicated by an imaginary line in FIG. The upper and lower ends of the rotating shaft 57 are rotatably supported by bearings 58, and the upper ends of the rotating shaft 57 are connected to the output shaft 53 a of the electric motor 53 via the connection member 60. In this embodiment, a shim 61 for adjusting the mounting position is interposed between the upper bearing 58 and the restraining plate 59.

  As shown in FIG. 6, the suppression plate 59 is provided with a through hole 59 a for protruding the upper end of the rotating shaft 57, and an oil passage 62 is provided on the surface 59 b on the second cylinder head cover 52 side. is there. In order to correspond to the two electric motors 53, the suppression plate 59 of this embodiment has two through holes 59a. The oil passage 62 is a groove having a U-shaped cross-section, and an oil reservoir 62a provided almost immediately below an oil passage 63 for lubricating oil, which will be described later, and the lubricating oil accumulated in the oil reservoir 62a are supplied to the intake valve 1 A first groove 62b that leads to the through hole 59a on the side, and a second groove 62c that extends along the through hole 59a and guides the lubricating oil accumulated in the oil reservoir 62a to the through hole on the exhaust valve side. Both the first groove portion 62b and the second groove portion 62c are formed so that the oil reservoir portion 62a side is higher than the through hole 59a side, and the lubricating oil can pass through the first groove portion 62b and the second groove portion 62c by its own weight. is there.

  A wall portion of the second cylinder head cover 52 is opposed to an oil passage 62 as a lubricating oil guide passage on the driving means 51 side, and a portion of the lubricating oil supplied to the bearing of the cam shaft 4 of the cylinder head 2 is provided. An oil passage 63 is formed so that the portion can be supplied to the oil passage 62 of the restraining plate 59. The oil passage 63 is formed inside the front wall 52 a and the upper wall 52 b of the second cylinder head cover 52. The oil passage 63 is connected to a branch passage for supplying the lubricating oil to the camshaft 4 in the lubricating oil passage provided in the cylinder head 2 via the bearing of the camshaft 4. Then, after extending upward from the cylinder head 2, it proceeds laterally through the front wall 52 a and then extends into the upper wall 52 b to reach a position above the oil reservoir 62 a of the oil passage 62.

  In the above configuration, the variable valve lift type valve gear 3 is configured such that the cam shaft 4 rotates and the cam 5 contacts the roller body 11 provided at one end portion, that is, the upper end of the swing arm 6 during the operation of the engine 100. Thus, the rocker arm 6 is swung around a contact point with a fulcrum roller 7 rotatably provided on the operation shaft 8, and the rocker arm 10 that contacts the lower end of the rocking arm 6 is moved. Rock. As a result, the intake valve 1 opens and closes. In this case, the operating shaft 8 is rotated by the driving means 51 in accordance with the operating state of the engine 100, and the position of the fulcrum roller 7 with respect to the swing arm 6, that is, the contact point between the fulcrum roller 7 and the swing arm 6 is determined. To change. The lift amount of the intake valve 1 is controlled by changing the contact point between the fulcrum roller 7 and the swing arm 6 in this way.

  In this case, the contact point of the fulcrum roller 7 with respect to the swing arm 6 is changed by rotating the operating shaft 8 forward and backward. The operation shaft 8 is rotated by driving the gear device 54 by operating the electric motor 53. In the gear device 54, the meshed worm wheel 56 rotates by rotating the worm gear 55 by the electric motor 53. When the worm wheel 56 rotates, the operating shaft 8 rotates, and the position of the operating shaft 8 relative to the swing arm 6 of the fulcrum roller 7 moves.

  During the operation of the engine 100, an upward external force acts on the operation shaft 8 via the fulcrum roller 7 according to the swing of the swing arm 6. For this reason, although the rotating shaft 57 tends to move upward, the suppression plate 59 suppresses the movement of the rotating shaft 57. Therefore, this external force is hardly transmitted to the output shaft 53 a of the electric motor 53.

  Further, since the lubricating oil circulates through the cylinder and the cylinder head 2 while the engine 100 is in operation, a part of the lubricating oil is suppressed from the cylinder head 2 and the oil passage 63 in the second cylinder head cover 52. It is supplied to the gear device 54 through an oil passage 62 on the surface of the plate 59. That is, the lubricating oil supplied from the cylinder head 2 is introduced into the oil passage 63 and drops from the oil passage 63 toward the oil passage 62 above the oil reservoir 62 a that is the oil inflow end of the oil passage 62. Thus, the lubricating oil that has moved from the cylinder head 2 to the restraining plate 59 flows out from the oil reservoir 62a, flows through the first groove portion 62b and the second groove portion 62c of the oil passage 62, and appropriately upwards from the through-hole 59a. It drops on the worm gear 55 and the worm wheel 56 through the bearing 58 located. The lubricating oil that has come into contact with the gear device 54 then falls to the cylinder head 2, mixes with the lubricating oil supplied to the cam shaft 4 of the cylinder head 2, reaches the oil pan, and is cooled.

  In the case of this embodiment, as described above, the second cylinder head cover 52 and the restraining plate 59 form a lubricating oil supply path, and therefore a pipe material or the like for guiding the lubricating oil to the gear device 54 is omitted. And the number of parts can be reduced. Also, by providing the oil passage 62 in the suppression plate 59, the lubricating oil can be supplied to the gear device 54 of the driving means 51 of the variable valve lift type valve gear 3 of both the intake valve 1 and the exhaust valve. The structure can be simplified despite the fact that the lubricating oil is supplied to two locations.

  As described above, the lubricating oil is continuously supplied to the gear device 54 via the oil passage 63 of the second cylinder head cover 52 and the oil passage 62 of the suppression plate 59, but stagnates in the gear device 54. Therefore, solid matter such as lump of oil and sludge existing in the lubricating oil can be prevented from adhering to the gear device 54. As a result, the gear device 54 can always be operated smoothly. Further, since the lubricating oil circulates without stagnation, the gear device 54 can be efficiently cooled.

  In addition, this invention is not limited to the above-mentioned embodiment.

  In the above-described embodiment, the fulcrum portion is configured by a fulcrum roller. Any structure may be used.

  In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

The principal part expanded sectional view in one cylinder which shows embodiment of this invention. The top view of the 2nd cylinder head cover of the embodiment. The front view of the 2nd cylinder head cover of the embodiment. The fragmentary perspective view which shows the state which attached the 2nd cylinder head cover to the cylinder head of the embodiment. The front view which shows the drive means of the embodiment in a partial cross section. The fragmentary perspective view which shows the attachment part of the drive means in the cylinder head of the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Intake valve 3 ... Valve lift variable type valve gear 4 ... Cam shaft 5 ... Cam 6 ... Swing arm 7 ... Supporting roller 8 ... Valve lift variable operation shaft 59 ... Inhibition plate 54 ... Gear device 53 ... Electric motor 62 ... Oil passage 63 ... Oil passage 52 ... Second cylinder head cover

Claims (1)

An internal combustion engine comprising a valve lift variable valve operating device for at least one of an intake valve and an exhaust valve between an upper part of a cylinder head and a cylinder head cover,
The variable valve lift type valve operating device is configured such that a cam provided on a cam shaft that rotates in conjunction with a crankshaft rotates in contact with one end portion of a swing arm, so that the swing arm becomes an operation shaft for variable valve lift. It is configured to swing around a contact point with the provided fulcrum and open and close a valve that contacts the other end of the swing arm by swinging the swing arm.
Further, a valve device is provided by a gear device disposed at the end of the valve lift varying operation shaft by a restraining plate that restrains a reaction force from the valve lift varying operation shaft and an electric motor that drives the gear device. It is configured to be able to move the contact point with the swing arm of the fulcrum portion in the longitudinal direction of the swing arm by rotating the lift variable operation shaft,
An electric motor is mounted on the outer surface of the cylinder head cover so that its output shaft faces downward and is substantially perpendicular to the valve lift variable operation shaft,
The suppression plate includes an oil passage that guides the lubricating oil dropped on the upper surface to the gear device,
An internal combustion engine comprising an oil passage that guides lubricating oil supplied from a cylinder head so that a cylinder head cover is dropped onto an oil passage of a restraining plate.

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