JP4552203B2 - Engine superstructure - Google Patents

Description

  The present invention relates to an upper structure of an engine provided with a variable valve operating device.

  There has been proposed a variable valve gear that can change the lift amount of an intake valve and an exhaust valve of an engine. For example, Patent Document 1 includes a link mechanism that converts the rotational motion of a shaft that rotates in synchronization with the rotation of a crankshaft of an engine into the swing motion of a swing cam member, and forcibly moves the operating position of the link mechanism. It has been proposed to change the swing angle range of the swing cam member by changing the displacement, thereby changing the lift amount of the valve.

  In this type of variable valve operating apparatus, a drive actuator is required to variably control the valve lift amount. However, the installation space of the engine is required to be reduced year by year, and the installation space of the drive actuator needs to be devised. It is difficult for the side portion of the engine to secure the drive actuator installation space in consideration of the installation space of other accessories. In view of this, an arrangement space for the drive actuator includes the cylinder head.

JP 2005-69043 A

  However, in the configuration in which the ignition unit that ignites the air-fuel mixture in each cylinder protrudes above the cylinder head, it is necessary to dispose the drive actuator to avoid the ignition unit. Further, in a configuration in which a head cover for preventing scattering of lubricating oil or the like is provided on the cylinder head, it is desirable that maintenance of the ignition unit and the drive actuator can be performed without removing the head cover.

  Accordingly, an object of the present invention is to arrange the drive actuator of the variable valve operating device in a compact manner on the cylinder head and to ensure maintenance.

  According to the present invention, in an upper structure of an engine including a cylinder head of a multi-cylinder engine having a variable valve operating device and a head cover that covers an upper portion of the cylinder head, the variable valve operating device includes a valve for each cylinder. And a bracket provided on the cylinder head and supporting the drive actuator, wherein the bracket is a hole through which one of the ignition units of each cylinder is inserted. And a bottom wall that forms an arrangement area for the upper part of the ignition unit that is inserted through the hole and the drive actuator, the head cover includes an opening that exposes the arrangement area, An engine upper structure characterized by having an inner peripheral wall portion extending downward so as to surround the installation region is provided.

  According to this configuration, the bottom wall of the bracket has the hole, and forms the arrangement region of the upper part of the ignition unit together with the drive actuator, so that the drive actuator is connected to the ignition unit. The drive actuator can be arranged close to the upper part, and the drive actuator can be arranged compactly on the cylinder head. In addition, since the head cover has the opening, maintenance of the ignition unit and the drive actuator having the upper portion disposed in the arrangement region can be performed without removing the head cover, and maintainability is also ensured. can do. Further, since the head cover has the inner peripheral wall portion, the shielding property of the arrangement area is improved, and the lubricating oil of the cylinder head is prevented from scattering into the arrangement area.

  In the present invention, the variable valve device rotates in synchronization with the crankshaft of the engine, extends in parallel with the cylinder row direction of the engine, and the drive shaft is used as an axis for each cylinder. A swing cam member that is swingably provided and lifts the valve of each cylinder by the swing motion, a control shaft that is rotated by using the drive actuator as a drive source, and extends parallel to the drive shaft, and each cylinder A control arm that is provided on the control shaft and is rotated by rotation of the control shaft, and connects the control arm and the swing cam member, and the swing cam member according to a rotation position of the control arm. And a link mechanism that changes the lift characteristics of the valve by changing the swing angle range of the drive actuator. An electric motor disposed in a direction perpendicular to the shaft, a drive shaft having a worm gear is attached to the output shaft of the electric motor, and a worm wheel meshing with the worm gear is attached to the control shaft; The rotational force of the electric motor is transmitted to the control shaft, the bracket is erected from the end of the bottom wall to define the arrangement area, and the side wall to which the electric motor is attached, and the side wall And a support wall that is provided on the opposite side of the arrangement region and supports the tip of the drive shaft, and a connecting portion that connects the support wall and the side wall, and the head cover includes the support A configuration covering the wall and the connecting portion can be employed.

  According to this configuration, the power transmission mechanism between the electric motor that is the drive actuator and the control shaft is configured by the worm gear and the worm wheel, so that the power transmission mechanism can be arranged more compactly. In addition, the head cover can prevent the lubricating oil from scattering from the power transmission mechanism to the outside.

  In the present invention, the cylinder head includes a main body portion and a holder portion, the drive shaft is pivotally supported by the main body portion and the holder portion, and the control shaft and the bracket are mounted on the holder portion. The installed configuration can be adopted.

  According to this configuration, by providing the holder portion, it is possible to utilize an existing cylinder head as the main body portion.

  Moreover, in this invention, the structure which the bottom face of the said bracket is located on the same plane as the attachment surface of the said head cover and the said cylinder head is employable.

  According to this structure, it becomes easy to define the sealing surface of the bracket and the head cover by design.

  In the present invention, the bracket is disposed on the front side of the engine, the ignition unit inserted through the hole is an ignition unit of a first cylinder, and the drive actuator is inserted through the hole. The structure arrange | positioned rather than the said ignition unit ahead of the said engine is employable.

  According to this configuration, the engine height can be increased only on the front side of the engine due to the presence of the drive actuator and the bracket.

  As described above, according to the present invention, the drive actuator of the variable valve operating apparatus can be arranged compactly on the cylinder head, and maintainability can be ensured.

  FIG. 1 is a diagram showing an overall configuration of a variable valve operating apparatus A and a valve operating apparatus B constituting an upper structure of an engine according to an embodiment of the present invention, and FIG. 2 is a partially exploded perspective view of the variable valve operating apparatus A. It is. In this embodiment, an application example to an in-line four-cylinder engine is assumed, and the variable valve apparatus A is for the intake valve 1 and the valve apparatus B is for the exhaust valve 2. In the present embodiment, the intake valve 1 and the exhaust valve 2 are each two valves, which is a four-valve double overhead cam system.

  In this embodiment, an example in which the present invention is applied to a valve operating device for an intake valve is illustrated. However, the present invention may also be applied to a valve operating device for an exhaust valve or a valve operating device for both an intake valve and an exhaust valve. it can. In this document, the engine rear side means the output side of the engine (the side where the crankshaft is connected to the transmission), and the engine front side means the power transmission mechanism from the crankshaft to the camshaft and drive shaft described later. The side where is placed. Further, when each cylinder is indicated individually, it is indicated by a number counted from the front side of the engine. For example, the first cylinder is indicated as # 1.

<Variable valve gear A>
The variable valve gear A includes a drive shaft 10 that rotates in synchronization with a crankshaft (not shown) of the engine. The drive shaft 10 extends in parallel with the cylinder row direction of the engine (the axial direction of the crankshaft (not shown)), and rotates in synchronization with the crankshaft, for example, by transmitting a rotational force from the crankshaft via a chain transmission mechanism. .

  The drive shaft 10 is provided with an eccentric cam member 20 that rotates (eccentric rotational movement) by the rotation of the drive shaft 10. The eccentric cam member 20 has a cylindrical shape with a circular cross section, and the center (center of the circular cross section) is deviated from the axis of the drive shaft 10. A total of four eccentric cam members 20 are provided for each cylinder. In this embodiment, each eccentric cam member 20 is formed integrally with the drive shaft 10. By forming the eccentric cam member 20 integrally with the drive shaft 10, it is possible to prevent the assembly error of the variable valve apparatus A from affecting the phase difference of the valve.

  The drive shaft 10 and the eccentric cam member 20 are finished by machining after creating a primary molded product in which they are integrated by, for example, casting. In this embodiment, each eccentric cam member 20 is formed on the drive shaft 10 with a phase difference of 90 degrees.

  The drive shaft 10 is provided so as to be swingable about the drive shaft 10, and a swing cam member 30 that opens and closes the intake valve 1 by its swing motion is provided for each cylinder. A total of four are provided. The swing cam member 30 includes cam portions 31 and 32, a cylindrical portion 33 that connects the cam portions 31 and 32, and an insertion hole 34 that is a through hole through which the drive shaft 10 is inserted. Of the cam portions 31 and 32, the cam portion 31 is formed with a hole 31a into which a connection pin 51a of a connection link member 50 described later is inserted.

  The cam portions 31 and 32 respectively correspond to the two intake valves 1 of the cylinder corresponding to the swing cam member 30, and a part of the peripheral surface thereof abuts on the roller 3 a of the rocker arm 3 for each intake valve 1.

  Here, in the case of this embodiment, since the eccentric cam member 20 is formed integrally with the drive shaft 10, if the swing cam member 30 is inserted from the end of the drive shaft 10, the eccentric cam member 20 is inserted between the eccentric cam members 20. The swing cam member 30 cannot be disposed. Therefore, in the case of the present embodiment, the swing cam member 30 is divided into two with a plane passing through the center line of the insertion hole 34 (that is, the axial center line of the drive shaft 10) as a boundary, and from the two divided bodies 30a and 30b. It is configured. The swing cam member 30 can be disposed between the eccentric cam members 20 by connecting the drive shaft 10 so as to be sandwiched between the divided bodies 30a and 30b. FIG. 4 is a perspective view showing details of the swing cam member 30, and FIG. 5A is an exploded perspective view of the swing cam member 30.

  Of the cylindrical portion 33, the central portion of the cylindrical portion 33 constitutes a pivoted support portion 33 a that is pivotally supported by the half bearing portions 5 a and 5 b provided in the cylinder head. A total of four boss portions 35a to 35d are formed in the cylindrical portion 33 on both sides of the pivoted support portion 33a so as to be integrated with the cylindrical portion 33 and straddle the divided bodies 30a and 30b.

  Each of the boss portions 35a to 35d is formed so as to protrude in the radial direction of the insertion hole 34 from the pivoted support portion 33a, and has holes 36a to 36d that communicate with each other when the divided bodies 30a and 30b are joined. Yes. Of these holes 36a to 36d, the part on the divided body 30a side is a screw hole. Thus, the divided bodies 30a and 30b are fastened by inserting the bolts 38 into the holes 36a to 36d and screwing them.

  In addition, holes 37a and 37b into which knock pins (not shown) are inserted are formed on the divided end faces of the divided bodies 30a and 30b, whereby the divided bodies 30a and 30b can be positioned.

  The side surfaces 35 a ′ to 35 d ′ of the boss portions 35 a to 35 d are in contact with the side surfaces of the bearing portion to constitute the thrust regulating surface of the swing cam member 30.

  As described above, in this embodiment, since the swing cam member 30 is divided into two, it is not necessary to assemble the swing cam member 30 from the end of the drive shaft 10, and the swing cam member 20 is located between the eccentric cam members 20. 30 can be assembled. Further, since the side surfaces 35a 'to 35d' of the boss portions 35a to 35d constitute a thrust restricting surface, the thrust restriction of the swing cam member 30 can be achieved. In this way, it is possible to improve the assembling property of the swing cam member 30 and the thrust regulation at once.

  Here, in the present embodiment, the boss portions 35a to 35d are arranged on both sides of the shaft support portion 33a (both sides in the axial direction of the drive shaft 10). For this reason, the thrust regulation of the swing cam member 30 can be achieved in both directions in the axial direction of the drive shaft 10. Specifically, the side surfaces 35 a ′ and 35 c ′ restrict the movement of the swing cam member 30 in one axial direction of the drive shaft 10, and the side surfaces 35 b ′ and 35 d ′ restrict the movement of the swing cam member 30 in the other axial direction of the drive shaft 10. .

  Further, the boss part 35 a and the boss part 35 d, and the boss part 35 b and the boss part 35 c are respectively arranged at positions that are symmetric with respect to the center line of the insertion hole 34. For this reason, not only the thrust regulation of the swing cam member 30 can be achieved in both directions in the axial direction of the drive shaft 10, but also the two divided bodies 30a and 30b can be more securely fastened.

  More specifically, for example, when only the boss portion 35a and the boss portion 35b are configured, thrust control of the swing cam member 30 can be achieved in both directions in the axial direction of the drive shaft 10, but the boss portion 35a and the boss portion 35b. There is no fastening force on the split surface on the opposite side, and fastening of the split bodies 30a and 30b is inferior to the case where the boss part 35c and the boss part 35d are provided.

  Next, as described above, the cam portions 31 and 32 partially contact the roller 3a of the rocker arm 3 for each intake valve 1 to form a cam surface. If the divided surfaces of the two divided bodies 30a and 30b pass through this cam surface, the slidability between the cam portions 31 and 32 and the roller 3a may be inferior.

  In the present embodiment, as shown in FIG. 4, among the peripheral surfaces of the cam portions 31 and 32, the region S <b> 1 forms a cam surface, and the remaining region is a non-cam surface. As shown in the figure, the divided surfaces of the two divided bodies 30a and 30b pass through the non-cam surface and do not pass through the region S1 which is the cam surface. With this configuration, even if the swing cam member 30 is divided into two parts as described above, the smoothness of the cam surface (S1) serving as the sliding surface is not impaired, and the sliding property can be maintained. Note that the cam surfaces (S1) have the same profile in the cam portions 31 and 32, and the lift operations of the two intake valves 1 lifted by the swing cam member 30 are performed synchronously.

  In the present embodiment, the four boss portions 35a to 35d are provided, but the number may be two. FIG. 5B is a perspective view of a swing cam member 30 ′ having two boss portions. In the figure, the same components as those of the swing cam member 30 are denoted by the same reference numerals and description thereof is omitted. The swing cam member 30 ′ has a configuration in which the boss portions 35 b and 35 c of the swing cam member 30 are omitted.

  Since the boss portions 35a and 35d are disposed on both sides of the supported shaft portion 33a, the thrust of the swing cam member 30 'can be regulated in both directions in the axial direction of the drive shaft 10. Further, since the boss portion 35a and the boss portion 35d are disposed at positions that are symmetric with respect to the center line of the insertion hole 34, the two divided bodies 30a and 30b can be more securely fastened.

  Next, returning to FIGS. 1 and 2, the configuration of the variable valve apparatus A will be further described. The offset link member 40 has an insertion hole 40a having substantially the same diameter as the outer diameter of the eccentric cam member 20, and the eccentric cam member 20 is rotatably inserted into the insertion hole 40a. That is, the offset link member 40 is connected to the eccentric cam member 20 by being externally fitted to the eccentric cam member 20. With the rotation of the drive shaft 10, the eccentric cam member 20 performs an eccentric rotational motion while the outer peripheral surface slides on the inner peripheral surface of the insertion hole 40 a of the offset link member 40.

  FIG. 6 is an exploded perspective view showing how the eccentric cam member 20 and the offset link member 40 are assembled. In the figure, reference numerals (# 1) to (# 4) attached to the reference numerals of the eccentric cam member 20 and the offset link member 40 indicate corresponding cylinder numbers.

  In the present embodiment, the eccentric cam member 20 is formed integrally with the drive shaft 10. Accordingly, when the offset link member 40 is assembled to the eccentric cam member 20, first, the eccentric cam members 20 (# 2) and (#) corresponding to the cylinder # 2 and the cylinder # 3 located on the center side of the cylinder row are used. 3) Attach the offset link members 40 (# 2) and (# 3) from the end of the drive shaft 10.

  Next, the offset link members 40 (# 1) and (# 4) are placed on the eccentric cam members 20 (# 1) and (# 4) corresponding to the cylinders # 1 and # 4 located on the end side of the cylinder row. It is mounted from the end of the drive shaft 10. The offset link member 40 (# 1) is mounted from the end of the drive shaft 10 on the engine front side, and the offset link member 40 (# 4) is mounted from the end of the drive shaft 10 on the engine rear side.

  In the case of this embodiment, the width d1 of the peripheral wall portion of the insertion hole 40a of the offset link member 40 is set to be the same as the width d2 of the eccentric cam member 20, and the side surface of the peripheral wall portion of the insertion hole 40a of the offset link member 40 And the side surface of the eccentric cam member 20 are flush with each other.

  The drive shaft 10 is provided with a groove 10a around the boundary with the eccentric cam member 20, and a snap ring 10b is fitted in the groove 10a. The snap ring 10b has a size that protrudes outward from the peripheral edge of the eccentric cam member 20 when the groove portion 10a is fitted, thereby restricting the axial thrust of the drive shaft 10 of the offset link member 40. be able to. In the case of this embodiment, the groove part 10a is provided in the drive shaft 10 in the both sides of the eccentric cam member 20, and the snap ring 10b is each fitted. Therefore, the thrust restriction of the offset link member 40 can be performed in both directions in the axial direction of the drive shaft 10. With such a configuration, the thrust regulation of the offset link member 40 can be performed in a small space.

  Next, returning to FIGS. 1 and 2, the offset link member 40 has a pair of connecting pins 41 a and 41 b at positions eccentric from the center of the insertion hole 40 a. The connecting pins 41a and 41b are parallel to the axis of the drive shaft 10, the connecting pin 41a protrudes from one side surface of the offset link member 40, and the connecting pin 41b protrudes from the other side surface of the offset link member 40. Yes.

  A hole 51b formed at one end of the connection link member 50 is inserted into the connection pin 41a. The connecting link member 50 is connected to the offset link member 40 by inserting the connecting pin 41a into the hole 51b, and is rotatably supported by the connecting pin 41a. A connecting pin 51 a is formed at the other end of the connecting link member 50.

  The axial center of the connecting pin 51a is parallel to the axial center of the drive shaft 10, and the hole 31a of the swing cam member 30 is inserted into the connecting pin 51a. The connecting link member 50 is connected to the swing cam member 30 by insertion of the connecting pin 51a into the hole 31a, and is also rotatably supported by the swing cam member 30, and the offset link member 40 and the swing cam. The member 30 is connected.

  Next, a hole 60 a formed at one end of the connection link member 60 is inserted into the connection pin 41 b of the offset link member 40. The connecting link member 60 is connected to the offset link member 40 by inserting the connecting pin 41b into the hole 60a, and is rotatably supported by the connecting pin 41b. A hole 60 b is formed at the other end of the connecting link member 60. A connecting pin 70a formed in the control arm member 70 is inserted into the hole 60b.

  A total of four control arm members 70 are provided, one for each cylinder. The control arm member 70 is attached to the control shaft 80 and is rotated by the rotation of the control shaft 80. The axes of the control shaft 80 and the connecting pin 70a are parallel to the axis of the drive shaft 10. In the present embodiment, the control arm member 70 and the drive shaft 10 are separated, but may be configured integrally.

  A worm wheel 81 is attached to the engine front side end of the control shaft 80. The worm wheel 81 meshes with a worm gear 91 a formed on a drive shaft 91 attached to the output shaft of the electric motor 90. The output shaft of the electric motor 90 is disposed in a direction orthogonal to the control shaft 80, and thus the axial direction of the drive shaft 91 is also orthogonal to the control shaft 80.

  The rotational force of the electric motor 90 is transmitted to the control shaft 80 via a power transmission mechanism constituted by the worm gear 91a and the worm wheel 81, and the control shaft 80 is rotated. In the present embodiment, the electric motor 90 is used as the drive actuator of the control shaft 80, but other types of drive actuators and power transmission mechanisms may be used.

  The control shaft 80 is also integrally formed with a regulating member 82 that regulates the rotation angle of the control shaft 80. The restricting member 82 has a semi-cylindrical portion, and the semi-cylindrical portion abuts against the wall portion of the cylinder head to mechanically restrict the rotation angle of the control shaft 80.

  Next, the operation of the variable valve gear A will be described with reference to FIGS. 3 (a) to 3 (d). As shown in FIG. 3A, one end of the rocker arm 3 is pivotally supported on the plunger tip of an HLA (Hydro-Crush Adjuster) 4 and can swing around the end. The other end of the rocker arm 3 is in contact with the valve stem 1 a of the intake valve 1. Thus, by the swinging motion of the swing cam member 30, the cam portions 31 and 32 come into contact with and slide against the roller 3a of the rocker arm 3, thereby causing the rocker arm 3 to swing.

  The rocking movement of the rocker arm 3 causes the intake valve 1 to move downward against the spring 1b, and also moves upward due to the restoring force of the spring 1b. The intake port is opened and closed by such lift operation of the intake valve 1.

  3A illustrates the cam portion 31, the configuration of the cam portion 32 and the rocker arm 3 is the same. In this embodiment, the rocker arm method is used, but a direct hitting method may be used.

  Next, the swinging motion of the swing cam member 30 will be described. When the eccentric cam member 20 performs an eccentric rotational movement by the rotation of the drive shaft 10, the offset link member 40 moves, but the offset link member 40 is connected to the control arm member 70 via the connection link member 60. The offset link member 40 performs a reciprocating arc motion. That is, the eccentric rotational movement of the eccentric cam member 20 is converted into a reciprocating arc movement by the offset link member 40.

  The reciprocating arc motion of the offset link member 40 is transmitted to the swing cam member 30 via the connecting link member 50, and the swing cam member 30 performs swing motion. That is, the eccentric rotational motion of the eccentric cam member 20 is converted into the swinging motion of the swing cam member 30, and the offset link member 40 and the connecting link members 50 and 60 are eccentric with the eccentric cam member 30 due to the rotation of the drive shaft 10. A link mechanism that converts the rotational motion into the swing motion of the swing cam member 30 is configured.

  The position of the reciprocating arc movement of the offset link member 40 is displaced by the rotational position of the control arm 70, that is, the rotational position of the control shaft 80. When the position of the reciprocating arc motion of the offset link member 40 changes, the swing angle range of the swing cam member 30 changes, and thereby the lift characteristics (lift amount and timing) of the intake valve 1 change.

  3A and 3B show the case of the high lift control state, and FIGS. 3C and 3D show the case of the low lift control state. In the high lift control state, the lift amount of the intake valve 1 is relatively large, and in the low lift control state, the lift amount of the intake valve 1 is relatively small. Normally, when the engine load increases, a high lift control state is set. The rotation of the control shaft 80 is controlled by the electric motor 90. Therefore, the electric motor 90 is a drive actuator that variably controls the lift characteristics of the intake valve 1.

<Valve operated device B>
Referring to FIG. 1, valve gear B includes a camshaft 110 that rotates in synchronization with an engine crankshaft (not shown). The camshaft 110 extends in parallel with the cylinder row direction of the engine (the axial direction of the crankshaft not shown), and, like the drive shaft 10, the rotational force from the crankshaft is transmitted via a chain transmission mechanism, for example. It rotates in synchronization with the shaft.

  A cam member 120 that is rotated by the rotation of the camshaft 110 is formed integrally with the camshaft 110. A total of eight cam members 120 are provided, two for each cylinder.

  Similarly to the intake valve 1, the exhaust valve 2 has a configuration using a rocker arm 3 and an HLA 4. The cam member 120 rotated by the rotation of the camshaft 110 abuts on and slides on the roller 3a of the rocker arm 3 to cause the rocker arm 3 to swing and cause the exhaust valve 2 to lift.

<Engine upper structure>
FIG. 7 is a partial view of the front surface (front end surface) of the engine, showing the superstructure of the engine according to one embodiment of the present invention. In the case of the present embodiment, the cylinder head 200 includes a main body portion 201 and a holder portion 202. The main body 201 is formed with a combustion chamber (not shown), an intake / exhaust port, and the like. The holder 202 is mainly provided as a support for the variable valve gear A.

  The drive shaft 10 and the camshaft 110 are pivotally supported by the main body portion 201 and the holder portion 202, and the control shaft 80 is pivotally supported by the holder portion 202. A bracket 210 that supports the electric motor 90 on the cylinder head 200 is attached on the holder portion 202.

  FIG. 8 is a plan view of the main body 201 on which the variable valve device A and the valve device B are mounted, and the holder portion 202 and the bracket 210 are omitted. The shaft support 5a described with reference to FIG. 4 is formed on the upper surface of the main body 201. A shaft support portion 5b (not shown in FIG. 8) corresponding to the shaft support portion 5a is formed on the lower surface of the holder portion 202, and these shaft support portions 5a and 5b support the shaft support portion 33a of the swing cam member 30 as a shaft support. To do.

  A shaft support portion 6 a that supports the camshaft 110 is formed on the upper surface of the main body portion 201. As in the case of the shaft support portions 5a and 5b, a shaft support portion (not shown) corresponding to the shaft support portion 6a is formed on the lower surface of the holder portion 202, and these shaft support portion cam shafts 110 are supported. In the case of the example of FIG. 8, a hole 201 a into which the ignition unit of each cylinder is inserted is formed on the upper surface of the main body 201.

  By configuring the cylinder head 200 with the main body 201 and the holder 202, the existing cylinder head is utilized as the main body 201, and the holder valve 202 is attached to the cylinder head 200 so that the variable valve device A is not provided. The variable valve gear A can also be mounted on the engine.

  Next, the bracket 210 will be described. FIG. 9 is a perspective view of the bracket 210. FIG. 10 is a partial plan view of the cylinder head 200 on the front side of the engine. The bra racket 210 has a bottom wall 211, side walls 212 and 213, and a peripheral edge 214 slightly raised from the surface of the bottom wall 211, and in this embodiment, is attached to the front side of the engine.

  A plurality of boss portions 211 d are formed on the bottom wall 211, and bolts are inserted through the boss portions 211 d to be fixed to the upper surface of the holder portion 202 of the cylinder head 200. The bottom wall 211 is also formed with a hole 211a that is a through hole into which one of the ignition units 95 of each cylinder (here, the ignition unit of cylinder # 1) is inserted. In the case of the present embodiment, the ignition unit 95 includes an ignition plug (not shown) and an ignition coil unit 95 a that is attached to the upper part of the ignition plug and forms the upper part of the ignition unit 95.

  The ignition coil unit 95a, which is the upper part of the ignition unit 95 that is inserted through the hole 211a, is disposed in a recess 211b that is stepped down from the surface of the bottom wall 211, and is fixed to the shelf 211c of the bottom wall 211.

  An electric motor 90 is fixed to the side wall 213. The bottom wall 211 is defined by the side walls 212, 213 and the peripheral edge 214, and forms an arrangement region S2 for the ignition coil unit 95a and the electric motor 90. In the case of the present embodiment, the electric motor 90 is disposed on the front side of the engine with respect to the ignition unit 95 inserted through the hole 211a.

  A through hole (not shown) is formed in the side wall 213, and the output shaft of the electric motor 90 and the drive shaft 91 are inserted therethrough. The tip of the drive shaft 91 is pivotally supported by a bearing 215 a provided on the support wall 215.

  The support wall 215 is provided on the side opposite to the arrangement region S <b> 2 with respect to the side wall 212, and is integrally connected to the side wall 212 by a pair of connecting portions 216. Boss portions 215b are formed at the lower portions on both sides of the support wall 215, and bolts are inserted through the boss portions 215a to be fixed to the upper surface of the holder portion 202 of the cylinder head 200. A drive shaft 91 passes between the connecting portions 216.

  Next, the configuration of the head cover that covers the top of the cylinder head 200 will be described. FIG. 11A is a partial plan view of the front side of the engine of the cylinder head 200 to which the head cover 220 is attached, and FIG. 11B is an end view taken along the line XX of the head cover 220.

  The head cover 220 bulges upward on the front side of the engine where the bracket 200 is disposed to cover the bracket 200 and the like, and has an opening 220a that exposes the disposed region S2 in the bulged portion. The arrangement region S2 is exposed by the opening 220a, but other portions (for example, the periphery of the support wall 215, the connecting portion 216, etc.) are covered by the head cover 220.

  Moreover, it has the inner peripheral wall part 221 extended below (cylinder head 200 side) so that arrangement | positioning area | region S2 may be enclosed in the periphery of the opening part 220a. A sealing material 221a is attached to the lower end of the inner peripheral wall portion 221 over the entire periphery. The sealing material 221a is in close contact with the upper surfaces of the side walls 212, 213 and the peripheral edge 214, and the liquid-tightness of the portion other than the arrangement region S2 exposed through the opening 220a is secured.

  A seal member 220b is also attached to the outer periphery of the head cover 220 over the entire periphery. The seal material 220b is in close contact with the upper surface of the peripheral edge of the holder portion 202, and ensures liquid tightness between the valve operating space inside the head cover 220 and the outside. As shown in FIG. 7, the bottom surface of the bracket 210 is located on the same plane as the mounting surface (the upper surface S3 of the holder 202) between the head cover 220 and the cylinder head 200.

  In this way, the head cover 220 covers the entire upper surface of the cylinder head 200 except for the arrangement region S, and ensures the fluid tightness between the valve operating space and the outside. However, as shown by the ignition unit 95 (# 2) corresponding to the cylinder # 2, the head cover 220 is not shown for inserting the ignition units 95 corresponding to the cylinders # 2 to # 4 in order to improve maintainability. The respective ignition units 95 can be attached to and detached from the cylinder head 200 without removing the head cover 220.

  In the present embodiment, the bottom wall 211 of the bracket 210 has a hole 211a, and forms the arrangement region S2 of the ignition coil unit 95a of the ignition unit 95 together with the electric motor 90, thereby making the electric motor 90 an ignition coil unit. The electric motor 90 can be disposed on the cylinder head 200 in a compact manner.

  Further, since the head cover 220 has the opening 220a, the maintenance of the ignition unit 95 and the electric motor 90 in which the ignition coil unit 95a is arranged in the arrangement region S2 can be performed without removing the head cover 220, and the maintenance performance is improved. Can also be secured. Further, since the head cover 220 has the inner peripheral wall portion 221, the shielding property of the arrangement region S2 is improved, and the lubricating oil of the cylinder head 200 is prevented from scattering into the arrangement region S2.

  In addition, since the power transmission mechanism between the electric motor 90 and the control shaft 80 is configured by the worm gear 91a and the worm wheel 81, the power transmission mechanisms can be arranged more compactly because the axial directions of both are orthogonal. Further, the head cover 220 can prevent the lubricating oil from scattering from the power transmission mechanism to the outside.

  Further, since the bottom surface of the bracket 210 is located on the same plane as the mounting surface of the head cover 220 and the cylinder head 200, it is easy to define the sealing surface between the bracket 210 and the head cover 220 in design.

  In the present embodiment, the bracket 210 is disposed on the front side of the engine, the ignition unit 95 inserted through the hole 211a is an ignition unit of cylinder # 1, and the electric motor 90 is more engine-driven than the ignition unit 95. Since it is disposed on the front side, the engine height can be increased only on the front side of the engine due to the presence of the electric motor 90 and the bracket 210. For this reason, the engine height can be lowered from the periphery of the cylinder # 2 to the rear side of the engine. For example, a coherent space is provided in which auxiliary equipment such as an air cleaner is disposed above the engine.

It is a figure which shows the whole structure of the variable valve apparatus A and the valve apparatus B which comprise the upper structure of the engine which concerns on one Embodiment of this invention. FIG. 2 is a partially exploded perspective view of the variable valve operating apparatus A. FIG. (A) thru | or (d) are operation | movement explanatory drawings of the variable valve apparatus A. FIG. 4 is a perspective view showing details of a swing cam member 30. FIG. (A) is an exploded perspective view of the swing cam member 30, and (b) is a perspective view of a swing cam member 30 'having two boss portions. FIG. 4 is an exploded perspective view showing how the eccentric cam member 20 and the offset link member 40 are assembled. It is a fragmentary view of the front surface (front side end surface) of the engine showing the superstructure of the engine according to one embodiment of the present invention. It is a top view of the main-body part 201 carrying the variable valve apparatus A and the valve apparatus B. FIG. 5 is a perspective view of a bracket 210. 2 is a partial plan view of a cylinder head 200 on the engine front side. FIG. FIG. 11A is a partial plan view of the front side of the engine of the cylinder head 200 to which the ha head cover 220 is attached, and FIG. 11B is an end view taken along the line XX of FIG.

Explanation of symbols

A Variable valve operating device S2 Arrangement area 90 Electric motor 95 Ignition unit 95a Ignition coil unit 200 Cylinder head 210 Bracket 211 Bottom wall 220 Head cover 220a Opening 221 Inner peripheral wall

Claims (5)

In the upper structure of the engine comprising a cylinder head of a multi-cylinder engine having a variable valve operating device, and a head cover that covers the upper portion of the cylinder head,
The variable valve operating device is
A drive actuator for variably controlling the valve lift characteristics of each cylinder;
A bracket provided on the cylinder head and supporting the drive actuator;
The bracket is
Having a hole through which one of the ignition units of each cylinder is inserted, and having a bottom wall forming an upper region of the ignition unit through which the hole is inserted and a region where the drive actuator is disposed;
The head cover is
An opening that exposes the placement region;
An inner peripheral wall portion extending downward to surround the arrangement region;
An upper structure of the engine characterized by comprising: The variable valve operating device is
A drive shaft that rotates in synchronization with a crankshaft of the engine and extends in parallel with a cylinder row direction of the engine;
An oscillating cam member provided for each cylinder so as to be oscillatable about the drive shaft, and for lifting the valve of each cylinder by the oscillating motion;
A control shaft that is rotated using the drive actuator as a drive source and extends parallel to the drive shaft;
A control arm provided on the control shaft for each cylinder and rotated by rotation of the control shaft;
A link mechanism that connects the control arm and the swing cam member, and changes a lift angle of the valve by changing a swing angle range of the swing cam member according to a rotation position of the control arm. And comprising
The drive actuator is an electric motor having an output shaft arranged in a direction orthogonal to the control shaft,
A drive shaft having a worm gear is attached to the output shaft of the electric motor, and a worm wheel meshing with the worm gear is attached to the control shaft, whereby the rotational force of the electric motor is transmitted to the control shaft,
The bracket is erected from an end of the bottom wall to define the arrangement area, and a side wall to which the electric motor is attached,
A support wall provided on the side opposite to the arrangement region with respect to the side wall, and supporting a tip of the drive shaft;
A connecting portion for connecting the support wall and the side wall;
Have
The engine upper structure according to claim 1, wherein the head cover covers the support wall and the connecting portion. The cylinder head is composed of a main body part and a holder part,
The drive shaft is pivotally supported by the body part and the holder part,
The upper structure of the engine according to claim 2, wherein the control shaft and the bracket are mounted on the holder portion.   4. The engine upper structure according to claim 1, wherein a bottom surface of the bracket is located on the same plane as a mounting surface of the head cover and the cylinder head. 5. The bracket is disposed on the front side of the engine,
The ignition unit inserted through the hole is an ignition unit of a first cylinder,
The engine upper structure according to any one of claims 1 to 4, wherein the drive actuator is disposed on a front side of the engine with respect to the ignition unit inserted through the hole.

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