JP2009293574A - Upper structure of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure a displacement of a front cover and a strength with respect to load vibration while reducing the weight of a head cover in an engine wherein an upper part of the front cover is connected and fastened to the head cover and an actuator such as an electric motor which is a heavy object is disposed on the upper part of the front cover. <P>SOLUTION: The head cover 6 is divided into a front end member 20 and a head cover body member 30, and the front end member 20 which is made by cast metal is provided with: a front flange part 21 face contacting a chain cover 7; a side flange part face contacting a sidewall part of an engine body (cam carrier 2); a seal surface part 24 rising from the side flange part in an arch-like shape and forming an outward seal surface; and a stay part 25 supported by an upper surface of the engine body. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is a multi-cylinder engine in which an upper part of a front cover that covers the front end side of the engine body is joined and fastened to a head cover that covers the upper part of the engine body, and an actuator such as an electric motor that is a heavy object is attached to the upper part of the front cover. The present invention relates to an upper structure of an engine provided.

For example, an engine mounted on an automobile is a multi-cylinder engine. Generally, an upper part of an engine body including a cylinder block and a cylinder head, that is, an upper part of a cylinder head or a cylinder head has a camshaft on the cylinder head body. When the supporting cam carrier is provided as a separate body, the upper part of the cylinder head including the cam carrier is covered with a head cover, and the front end of the engine body in the cylinder row direction is aligned with the head cover to the front cover such as a timing belt cover or a chain cover. The upper rear side of the front cover is joined and fastened to the front part of the head cover with a vertical mating surface (see, for example, Patent Document 1).
Japanese Utility Model Publication No. 5-89845

  By the way, it is desirable that the head cover covering the upper part of the engine body is made of resin for weight reduction. However, in a vehicle engine or the like, a front cover made of metal casting is provided on the front side of the engine body as described above, and the upper rear side of the front cover is fastened to the front part of the head cover with a vertical mating surface. In such a case, load vibration of the front cover acts on the head cover via the fastening portion. The head cover must be strong enough to withstand such loads and vibrations through the front cover.

  In particular, in recent engines, as a variable valve timing device (VVT), the conventional hydraulic VVT has poor operability when cold, so it is considered to adopt an electric VVT that drives the motor instead of the hydraulic pressure. When such an electric VVT is employed, the main body constituting the phase varying mechanism of the VVT is assembled to the front end portion of the camshaft, but the electric motor as a drive source is attached to the front cover. That is, a heavy electric motor is attached to the top of the front cover. Therefore, deformation of the front cover and load vibration increase, which affects the head cover. Resin head covers are limited in strength against such displacement and load vibration from the front cover side.

  According to the present invention, in such a multi-cylinder engine, an upper part of a front cover that covers the front end side of the engine body is joined and fastened to a head cover that covers the upper part of the engine body, and an actuator such as an electric motor that is heavy on the upper part of the front cover It is an object of the present invention to provide an engine upper structure capable of ensuring the strength against displacement of the front cover and load vibration while reducing the weight of the head cover.

  The upper structure of the engine of the present invention is such that the upper part of an engine body having a cylinder head of a multi-cylinder engine is covered with a head cover, and the front end side in the cylinder row direction of the engine body is covered with a front cover extending upward from the engine body. An engine upper structure in which the upper rear side of the cover is joined and fastened to the front part of the head cover, the front cover is made of metal casting, and an actuator related to a camshaft for valve actuation is provided on the upper part. The front cover is divided into a front edge member and a head cover body member to which the upper part of the front cover is joined. The front edge member is made of metal casting, while the head cover body member is made of resin molding, and the front edge member is attached to the front cover. The front flange part that makes contact, the side flange parts that make contact with the side wall parts on both sides in the width direction of the engine body, and the left and right parts A seal surface portion that rises in an arch shape from the side flange portion on the side, and a stay portion that is supported on the upper surface of the engine body, and the head cover body member has a seal surface portion that overlaps the seal surface portion of the front edge member on the front edge side. In addition, the seal surface portion of the head cover main body member is joined to the seal surface portion of the front edge member via the seal member.

  In this case, the main part of the head cover is a head cover main body member, which is made of resin molding, so that the overall weight can be reduced, and the displacement of the front cover and the transmission of load vibration by the actuator are made of metal casting. The front edge member that can ensure the strength can be effectively reduced, and the influence on the head cover main body member that is the main portion of the head cover can be suppressed.

  In the upper structure of the engine, the stay portion is preferably fastened to an intermediate portion in the width direction of the engine body. By doing so, the leading edge member can be effectively supported.

  In the upper structure of the engine, the front edge member is preferably fastened to the engine main body at three points, that is, a side flange portion and a stay portion on both the left and right sides. By doing so, the leading edge member can be supported in a balanced manner with a small number of fastening elements.

  This superstructure of the engine is particularly suitable when the actuator is an electric motor that operates a phase variable mechanism connected to a camshaft.

  Thus, according to the present invention, in a multi-cylinder engine, the upper part of the front cover that covers the front end side of the engine body is joined and fastened to the head cover that covers the upper part of the engine body, and the electric motor that is a heavy object on the upper part of the front cover In an engine provided with an actuator such as the above, it is possible to ensure strength against displacement of the front cover and load vibration while reducing the weight of the head cover.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 20 show an example of an embodiment of the present invention. 1 is a front view of the upper part of the engine, FIG. 2 is a longitudinal sectional view of an intake cam shaft center part of the upper part of the engine, FIG. 3 is a plan view of a head cover part of the engine, and FIG. 5 is a sectional view taken along the line BB in FIG. 3, FIG. 6 is a sectional view taken along the line CC in FIG. 3, FIG. 7 is a plan view of the head cover body member, FIG. FIG. 10 is a bottom view of the head cover main body member, FIG. 11 is a plan view of the head cover front edge member, FIG. 12 is a front view of the head cover front edge member, and FIG. 13 is a rear view of the head cover front edge member. 14 is a bottom view of the head cover leading edge member, FIG. 15 is a sectional view taken along line EE in FIG. 11, FIG. 16 is a sectional view taken along line FF in FIG. 19 is a perspective view of the chain guide attached to the head cover front edge member. FIG. 19 shows the front of the head cover. Front view of a state of attaching the chain guide member, FIG. 20 is a bottom view of a state of attaching the chain guide of the head cover leading edge member.

  The engine of this embodiment is an in-line four-cylinder engine for automobiles, and the upper surface of the cylinder head 1 (cylinder head body) is separated from the cylinder head 1 and is covered with a cam carrier (lower carrier) 2 that is an integral structure. 2), the camshaft 3 for driving the exhaust valve and the camshaft 4 for driving the intake valve are rotatable on a bearing portion constituted by the cam carrier 2 and the upper carriers 5A and 5B assembled on the upper surface thereof. It is pivotally supported (see FIGS. 4 to 6).

  A head cover 6 that covers the upper portion of the engine body is fastened to the upper surface of the cam carrier 2 (see FIGS. 2 and 4 to 6), and the front end side in the cylinder row direction of the engine body is as high as the head cover 6. Covered with a chain cover 7 (front cover) (see FIGS. 1 and 2). The chain cover 7 is joined and fastened to the front portion of the head cover 6 at the upper rear side with a vertical mating surface (see FIGS. 2 and 4 to 6).

  The chain cover 7 is made of metal casting (for example, made of an aluminum alloy). A vacuum pump 8 is attached to the upper side of the chain cover 7 and an electric motor 9 of an electric VVT (Valve Timing Variable Device) is attached to the intake side. (See FIG. 1). The electric VVT is known per se as described in, for example, Japanese Patent Laid-Open No. 2008-38886, and the apparatus main body 10 having the phase variable mechanism winds a timing chain (not shown). A unit with the intake-side drive sprocket 11 to be hung is assembled to the front end of the intake-side camshaft 4 (see FIG. 2).

  The head cover 6 is a divided body of a front edge member (head cover front edge member) 20 and a head cover body member 30 to which the upper part of the chain cover 7 is joined (see FIGS. 2 and 3). The leading edge member 20 is made of metal casting (for example, aluminum alloy), and the head cover body member 30 is made of resin molding.

  The engine of this embodiment has four cylinders, and has two spark plugs of a center plug 41 (see FIG. 6) and a side plug (not shown) for each cylinder, and an in-cylinder combustion chamber for each cylinder. In-cylinder pressure sensor 43 (see FIG. 5) for detecting the pressure in 42 is provided. An ignition coil unit 44 connected to each center plug 41 and an ignition coil unit 45 connected to each side plug are arranged on the upper portion of the engine body so as to protrude above the head cover 6 (head cover body member 30). (See FIGS. 2 and 3 to 6). Also, the cylinder pressure sensor 43 of each cylinder. It protrudes above the head cover 6 (head cover body member 30) (see FIGS. 2 and 5).

The center plug 41, the side plug (not shown), and the in-cylinder pressure sensor 43 are provided for each cylinder with the center plug 41 as the center and the side plug and the in-cylinder pressure sensor 43.
Are arranged on both sides in the cylinder row direction, and the side plug is located on the rear side of the cylinder (first cylinder) located on the front end side in the cylinder row direction (the left end side in FIG. 2 and the lower end side in FIG. 3). The in-cylinder pressure sensor 43 is arranged on the front side, and for the cylinder (second cylinder) located on the rear side of the first cylinder, the side plug is arranged on the front side and the in-cylinder pressure sensor 43 is arranged on the rear side. The positional relationship between the side plug and the in-cylinder pressure sensor 43 is reversed between the two cylinders, and the two adjacent cylinders are axisymmetric about the boundary between the cylinders (see FIG. 3).

  The head cover 6 includes a chain cover 7 on the front side of a region where the ignition coil unit 44 connected to the center plugs 41 of the four cylinders, the ignition coil unit 45 connected to the side plugs, and the in-cylinder pressure sensors 43 are located. Only the leading edge portion to which the bolt is fastened is divided from the light-weight head cover main body member 30 made of resin molding, which is located in the original head cover region, as a rigid metal leading edge member 20 (FIGS. 2 and 3). reference).

  The head cover main body member 30 includes a peripheral flange portion 31 in contact with a rear end side of the engine main body (cam carrier 2) and side walls on both sides in the width direction, a center plug 41 (ignition coil unit 44) of each cylinder, and a side plug (ignition). In the state where the coil unit 45) and the in-cylinder pressure sensor 43 protrude upward and the head cover 6 is fastened to the upper surface of the cam carrier 2, the center plug 41 (ignition coil unit 44) and side plug (ignition coil) of each cylinder A support boss portion 34 supported on the upper surface of the engine body (cam carrier 2), which includes circular and oval boss holes 32 and 33 that allow the unit 45) and the in-cylinder pressure sensor 43 to be attached and detached; The seal faces inwardly rising from the both sides of the peripheral flange portion 31 at the inward direction (the region in which the grid diagonal lines are drawn in FIG. 10) Having a sealing surface portion 35 which forms a (see FIGS. 7-9). Further, a seal groove 36 for mounting a seal member (rubber seal) is formed on the lower surface of the peripheral flange portion 31 of the head cover main body member 30, and a similar seal groove 37 is formed on the lower surface peripheral portion of the support boss portion 34. It is formed (see FIG. 10).

  The front edge member 20 includes an arch-shaped front flange portion 21 that contacts the chain cover 7, left and right side flange portions 22 and 23 that contact the side wall portions on both sides in the width direction of the engine body (cam carrier 2), On the upper surface of the engine main body (cam carrier 2), the seal surface portion 24 that rises in an arch shape from the side flange portions 22 and 23 on both the left and right sides and forms an outward seal surface (a region hatched with a grid diagonal line in FIG. 11). And a stay portion 25 to be supported (see FIGS. 11 to 17).

  Further, the front edge member 20 is adjacent to the lower portion of the upper center of the front flange portion 21 that contacts the chain cover 7 and protrudes forward so as to enter the lower portion of the flange portion on the chain cover 7 side. A guide support portion 28 is provided (FIGS. 11, 12, and 14 to 17). A recess 29 for locking the chain guide is provided on the lower surface of the chain guide support 28 on the rear side of the center (see FIG. 14).

  A chain guide 60 (see FIG. 18) for holding the timing chain between the intake-side and exhaust-side drive sprockets is attached to the chain guide support portion 28 (see FIGS. 19 and 20).

  The chain guide 60 has a plate shape, the lower surface forms a guide surface, and has holding portions 61 and 62 that hold the chain guide support portion 28 by being fitted to the left and right ends on the upper surface side. On the end side, there is a locking projection 63 that fits into the recess 29 of the chain guide support portion 28 (see FIG. 18). The chain guide 60 is mounted so that the chain guide support portion 28 is fitted between the left and right holding portions 61 and 62 with the plate-shaped guide body facing down, and the locking protrusion 63 is attached to the chain guide support portion 28. Is engaged with and fixed to the recess 29 (see FIGS. 19 and 20).

  The front edge member 20 has bolt holes 26 (see FIG. 11) provided at three points of the left and right side flange portions 22 and 23 and a portion where the stay portion 25 is lowered by one step with respect to the engine body (cam carrier 2). 14) (see FIG. 3, FIG. 4, FIG. 11, FIG. 14, and FIG. 17). Further, the front edge member 20 is formed with a screw hole 27 for fastening with the head cover main body member 30 at a portion overlapping the seal surface of the seal surface portion 24 at the base portion of the stay portion 25 (see FIG. 11).

  In the head cover main body member 30, a seal surface portion 35 that forms an inward seal surface on the front edge side is overlaid on the seal surface portion 24 of the front edge member via a seal member (rubber seal) 36, and a peripheral flange portion. The bolt 52 is fastened to the engine main body (cam carrier 2) through a bolt hole 36 provided in 31, and the stay 53 of the front edge member 20 is sealed with a bolt 53 through a bolt hole 37 provided in the seal surface portion 35. It is fastened to a screw hole 27 in a portion overlapping the seal surface of the surface portion 24 (see FIGS. 2, 3, 5, and 6).

  According to this embodiment, even if the chain cover 7 exerts an influence of load and vibration on the head cover 6 side due to the weight of the electric motor 9 or the like, the front edge member 20 is made of metal casting like the head cover 6, and the cylinder head 1 is attached at three points including the stay portion 25, it is effectively suppressed from affecting the resin-molded head cover main body member 30.

  As mentioned above, although an example of an embodiment was explained, the present invention is not limited to this, and can be applied to an engine that does not have a cam carrier, an engine in which an actuator other than an electric motor is attached to the front cover, It can be implemented in various ways.

It is a front view of the upper part of the engine of the embodiment of the present invention. It is a longitudinal cross-sectional view in the intake cam shaft center part of the upper part of the engine of embodiment of this invention. It is a top view of the head cover site | part of the engine of embodiment of this invention. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is CC sectional drawing of FIG. It is a top view of the head cover main body member of the engine of the embodiment of the present invention. It is DD sectional drawing of FIG. It is a front view of the head cover main body member of the engine of the embodiment of the present invention. It is a bottom view of the head cover main body member of the engine of the embodiment of the present invention. It is a top view of the head cover front edge member of the engine of the embodiment of the present invention. It is a front view of the head cover front edge member of the engine of the embodiment of the present invention. It is a rear view of the head cover front edge member of the engine of the embodiment of the present invention. It is a bottom view of the head cover front edge member of the engine of the embodiment of the present invention. It is EE sectional drawing of FIG. It is FF sectional drawing of FIG. It is GG sectional drawing of FIG. It is a perspective view of the chain guide attached to the head cover front edge member of the engine of the embodiment of the present invention. It is a front view of the state where the chain guide of the head cover front edge member of the engine of the embodiment of the present invention was attached. It is a bottom view of the state which attached the chain guide of the head cover front edge member of the engine of embodiment of this invention.

Explanation of symbols

1 Cylinder head 2 Cam carrier (lower carrier)
3 Cam shaft (exhaust side)
4 Cam shaft (intake side)
5A, 5B Upper carrier 6 Head cover 7 Chain cover (front cover)
9 Electric VVT Electric Motor 10 Electric VVT Device Main Body (Phase Variable Mechanism)
DESCRIPTION OF SYMBOLS 11 Drive sprocket 20 Front edge member 21 Front flange part 22, 23 Side flange part 24 Seal surface part 25 Stay part 26 Bolt hole 30 Head cover main body member 31 Peripheral flange part 34 Support boss part 35 Seal surface part

Claims (4)

The upper part of the engine body having the cylinder head of the multi-cylinder engine is covered with a head cover, the front end side in the cylinder row direction of the engine body is covered with a front cover extending above the engine body, and the upper rear side of the front cover is covered. The upper structure of the engine joined and fastened to the front part of the head cover,
The front cover is made of metal casting, and an actuator related to a camshaft for valve actuation is provided on the upper part,
The head cover is a divided body of a front edge member and a head cover main body member to which the upper part of the front cover is joined, and the front edge member is made of metal casting, while the head cover main body member is made of resin molding,
The front edge member has an arch shape from the front flange portion that contacts the front cover, the left and right side flange portions that contact the side wall portions on both sides in the width direction of the engine body, and the left and right side flange portions. And a stay portion supported on the upper surface of the engine body,
The head cover main body member has a seal surface portion overlapping the seal surface portion of the front edge member on the front edge side, and the seal surface portion of the head cover main body member is joined to the seal surface portion of the front edge member via the seal member. The superstructure of the engine as a feature. The engine upper structure according to claim 1, wherein the stay portion is fastened to an intermediate portion in a width direction of the engine body. The engine upper structure according to claim 1 or 2, wherein the front edge member is fastened to the engine main body at three points of the left and right side flange portions and the stay portion. The upper structure of an engine according to claim 1, 2, or 3, wherein the actuator is an electric motor that operates a phase variable mechanism connected to the camshaft.

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