JP4619327B2 - Engine head structure - Google Patents

Description

  The present invention relates to the structure of a cylinder head portion of an engine, and more particularly to an overhead cam type engine having a cam chain chamber on the upper surface side of a cylinder head.

  In an overhead cam type engine, a cam mechanism for opening and closing the intake and exhaust valves of the engine is provided in the cylinder head. Therefore, a camshaft is rotatably held by the cylinder head, and a chain mechanism for transmitting the crankshaft rotation of the engine to the camshaft, and a cam for opening / closing the intake / exhaust valve according to the rotation of the camshaft. A cam chain chamber for disposing a mechanism and the like is formed, and a head cover is attached to cover the cam chain chamber in which the cam chain mechanism is disposed.

  In such a configuration, in order to machine a shaft hole for rotatably supporting the camshaft on the upper surface side of the cylinder head, a recess recessed in a semicircular shape is formed on the end wall surface in the camshaft direction of the cylinder head. It is formed. For this reason, when attaching the head cover to the cylinder head, it is necessary to seal not only the joint surface between the two but also the semicircular concave portion. In addition to the gasket, a configuration is employed in which a seal member having a semicircular shape in side view that closes the recess is sandwiched (see, for example, Patent Documents 1 to 3).

Utility Model Registration No. 2515054 Japanese Utility Model Publication No. 7-17936 JP 2003-343372 A

  These conventional configurations include a planar seal member that is sandwiched between the joint surfaces of the cylinder head and the head cover, and a semicircular seal member that closes the recess, and the semicircular seal member is composed of a single elastic body. In addition, since the sealing member has a structure that is exposed to the outside and easily receives external force, there is a problem that the holding force of the sealing member may be reduced or the sealing performance may be deteriorated. .

  In view of such problems, an object of the present invention is to provide a head structure of an engine having a configuration capable of firmly closing and sealing a semicircular recess of a cylinder head.

The engine head structure according to the present invention includes a cylinder block in which a cylinder chamber into which a piston is inserted is formed, and is mounted on the cylinder block so as to cover an opening of the cylinder chamber on the side facing the piston head. A cylinder head having a cam chain chamber that is open to the head, a head cover that is attached to the upper surface side end surface of the cylinder head so as to cover the cam chain chamber, and between the upper surface side end surface of the cylinder head and the head cover A seal member that is sandwiched and seals the joint between the two, a recess for processing a bearing portion of the camshaft is formed on the upper end surface of the cylinder head, and the seal member The upper end surface of the cylinder head excluding the recess and the lower end surface of the head cover Integrally with the flat seal portion made of elastic material sandwiched, and a projecting seal portion made of elastic material sandwiched between said recess mounted closes the recess the cover bottom surface between is configured to have the said projecting and metal reinforcing member on the inner surface side of the seal portion is provided integrally, the recess is formed in a semicircular shape in side view, the projecting seal portion is the elastic The material is formed in a semicircular shape that fits into the recess, and the reinforcing member is formed in a semicircular shape corresponding to the shape of the projecting seal portion , and the head seal side of the projecting seal portion is formed . outer flange portion protruding upward is formed at the outer end of the upper surface, the reinforcing member and the inner flange portion is formed to protrude from the inner end portion of the upper surface of the projecting seal portion on the upper end portion of the head cover side upwards And the protruding seal portion When the seal member is inserted into the recess and is sandwiched between the upper end surface of the cylinder head and the head cover, the inner and outer collar portions are positioned so as to sandwich the head cover from the inner side and the outer side. It is configured.

In the above-described head portion structure, it is preferable that the inner collar portion is provided in a pair of left and right positions so as to sandwich the outer collar portion on both sides of the outer collar portion in a side view .

In the head portion structure, it is preferable that a width between the inner and outer end portions in the plan view of the protruding seal portion is larger than a width between the inner and outer end portions in the plan view of the planar seal portion .

In the head unit structure, further, the outer collar portion formed in the projecting seal portion, the protruding amount of upward from the inner flange portion formed in the reinforcing member has a shape having increased Is preferred.

  According to the engine head portion structure according to the present invention configured as described above, the seal member that seals the joint portion between the cylinder head and the head cover integrally has the protruding seal portion that is made of an elastic member that closes the recess. Since the convex seal part made of an elastic member is reinforced by a metal reinforcing member, even if a force from the outside (or the inside) is applied to the projecting seal part, it is difficult to deform and the sealing performance is improved. While improving, it can prevent the protrusion-like seal part from dropping off effectively.

  In this configuration, if the projecting seal portion is composed of a semicircular elastic member that fits into the semicircular recess, and the reinforcing member is formed in a semicircular shape corresponding to this shape, the processing is simple. And the protruding seal part which consists of an elastic member can be reinforced effectively.

  The protruding seal portion and the reinforcing member are formed with flange portions protruding upward at the inner and outer end portions, and when these are sandwiched between the cylinder head and the head cover, the inner and outer flange portions are the head cover. If the structure is sandwiched between the inside and the outside, it is possible to prevent the protruding seal portion from moving relative to the head cover, to reliably prevent the seal portion from coming off, and to improve the sealing performance.

  Further, if the collar portion formed on the projecting seal portion is located outside the head cover and the collar portion formed on the reinforcing member is located inside the head cover, the projection is received by the internal pressure of the cam chain chamber. The protrusion-like seal portion can be firmly held by the reinforcing member against the action that the shape-like seal portion is pushed outward.

  Furthermore, if the protrusion formed on the protruding seal portion has a larger protruding amount than the flange formed on the reinforcing member, the protruding seal portion made of an elastic member is elastically opened to the outside. The head cover can be assembled by being deformed, and the head cover can be easily assembled while preventing the protruding seal portion from entering the cam chain chamber.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. An engine E having a head structure according to an embodiment of the present invention will be described with reference to FIGS.

  The engine E includes a crankcase 1 in which the crankshaft 2 is disposed and held, a cylinder block 5 that is joined to the upper end of the crankcase 1, a cylinder head 10 that is joined to the upper end of the cylinder block 5, A head cover 8 joined to the upper end of the cylinder head 10 is provided, and various engine constituent members are arranged therein. A cylinder liner 6 is inserted into the cylinder block 5, and a piston 4 is disposed in a cylindrical cylinder hole 6 a formed in the cylinder liner 6 so as to be movable in the axial direction. The piston 4 is connected to the crank portion 2 a of the crankshaft 2 through the connecting rod 3.

  The cylinder head 10 has a combustion chamber forming recess 13 formed on the lower surface, and an exhaust passage 11 having an exhaust port 11a opening in the recess 13 and an intake passage 12 having an intake port 12a are provided in the cylinder head 10. Is formed. The exhaust valve 20 and the intake valve 25 are attached to the cylinder head 10 as shown in FIG. 1 so that the lower end valve portions 21 and 26 can open and close the exhaust and intake ports 11a and 12a. The exhaust valve 20 and the intake valve 25 are urged in the closing direction by the valve springs 23 and 28. When no external force is applied, the valve portions 21 and 26 are exhausted and intake ports by the urge of the valve springs 23 and 28. 11a and 12a are closed. Further, as shown in FIG. 3, the tip plug portion protrudes into the combustion chamber forming recess 13 and the ignition plug 29 is attached to the cylinder head 10.

  As shown in FIG. 3, a cam chain chamber 14 is formed on the upper surface side of the cylinder head 10. The cam chain chamber 14 is formed of a recess opened on the upper surface side. An overhead type cam mechanism 30 is disposed here. The cam chain chamber 14 is connected to a cam chain disposition space 5a formed vertically through the inside of the right side in FIG. 3 and vertically through the side of the cylinder block 5, and a cam chain mechanism 35 is provided here. A driven sprocket 36 and a chain 37 are provided. A front view of the cylinder head 10 alone is shown in FIG. 5. As can be seen from this figure, the mount 15 for mounting the cam mechanism 30 protrudes upward in the head cover space (joining with the head cover 8). Projecting above the surface 10a).

  The cam mechanism 30 includes a camshaft 31 that is rotatably held by the mount portion 15, and exhaust and intake rocker arms 32 and 33 that are swung by the camshaft 31. The camshaft 31 has exhaust and intake cam portions 31a and 31b formed at two positions on the outer periphery, the shaft tip is rotatably inserted into a mounting hole 15b formed in the mount portion 15, and the shaft intermediate portion is attached. The hole 15a is rotatably supported via a bearing 15c and attached to the mount portion 15. The exhaust and intake rocker arms 32 and 33 are pivotally mounted with their central portions 32a and 33a pivotally connected to the mount portion 15, and cam followers 32b and 33b provided at one end are exhaust and intake cams. The pressing portions 32c and 33c provided at the other end abut against the upper end abutting portions 22 and 27 of the exhaust valve 20 and the intake valve 25, abutting against the portions 31a and 31b.

  When the camshaft 31 is rotated by the cam mechanism 30 having such a configuration, the exhaust and intake cam portions 31a and 31b push up the cam followers 32b and 33b at a predetermined timing, and the exhaust and intake rocker arms 32 and 33, the pressing portions 32c and 33c come into contact with the upper end contact portions 22 and 27 of the exhaust valve 20 and the intake valve 25 to push down, and the valve portions 21 and 26 connect the exhaust and intake ports 11a and 12a. Open.

  The exhaust and intake ports 11a and 12a are opened in synchronism with the reciprocation of the piston 4 due to the rotation of the crankshaft 2. For this reason, a chain 37 is hung on a drive sprocket (not shown) attached to the crankshaft 2, and this chain 37 is hung on a driven sprocket 36 attached to the end of the camshaft 31. The camshaft 31 is driven to rotate in synchronization with the rotation of the crankshaft 2.

  The head cover 8 is attached on the cylinder head 10 so as to cover the cylinder head 10 to which the cam mechanism 30 is attached from the upper surface side. At this time, a seal member 50, which will be described later, is sandwiched between them, and this portion is sealed so that internal oil or the like does not leak to the outside.

  As shown in FIG. 5, the mount portion 15 of the cylinder head 10 protrudes above the joint surface 10a with the head cover 8, but it is desirable to make the engine compact by minimizing the amount of protrusion. It is. For this reason, a semicircular recess 10b is formed at one end of the joint surface 10a of the cylinder head 10, and the mounting holes 15a and 15b for mounting the camshaft 31 are machined by inserting a tool through the recess 10b. It is like that. With this configuration, it is possible to reduce the position of the camshaft 31 and suppress the height of the engine to achieve compactness. However, it is necessary to close and seal the recess 10b.

  For this reason, in this engine E, the sealing member 50 having the configuration shown in FIGS. 6 to 8 is sandwiched between the cylinder head 10 and the head cover 8 so as to securely seal between the two including the recess 10b. I have to. The seal member 50 is mounted on the cylinder head joint surface 10a so as to surround the cam chain chamber 14, and is fitted into the recess 10b and a flat seal portion 51 sandwiched between the lower end surface of the head cover 8. It is comprised integrally from the protruding seal | sticker part 52 arrange | positioned.

  The flat seal portion 51 is formed in a flat plate shape from an elastic material, and has a linear protrusion 51 a extending in the longitudinal direction on the upper surface, and the linear receiving groove formed on the lower end surface of the head cover 8. (Not shown). The upper seal surface 53 of the projecting seal portion 52 extends and is connected to the same surface as the upper surface of the planar seal portion 51, and the linear projection 53a formed thereon is connected to the projection 51a. The upper surface seal surface 53 is integrally connected to be positioned on the joint surface 10 a of the cylinder head 10 and surround the cam chain chamber 14.

  The protruding seal portion 52 is formed in a semicircular shape in side view corresponding to the shape of the recess 10 b of the cylinder head 10 and protrudes downward from the upper surface seal surface 53. The outer surface side and upper and lower surfaces of the projecting seal portion 52 are made of the same elastic material as the flat seal portion 51, and a metal reinforcing plate 55 having a semicircular shape in side view is integrally provided on the inner surface side. A tongue-shaped first flange portion 54a is formed on the outer surface of the upper seal surface 53 of the projecting seal portion 52 and extends upward, and is formed on the inner and outer sides of the semi-cylindrical outer peripheral surface 52a of the projecting seal portion 52. Flange-like second and third flange portions 54b and 54c extending in the direction are formed. A plurality of small link projections 52b are formed on the semi-cylindrical outer peripheral surface 52a, and when the projecting seal portion 52 is inserted into the recess 10b, these small projections 52b are formed on the inner peripheral surface of the recess 10b. It is configured to abut and exhibit good sealing performance.

  On the other hand, the upper end portion of the reinforcing plate 55 is bent inward, and fourth flange portions 55b and 55b protruding upward at two locations on the inner end of the upper surface sealing surface 53 are formed. Similarly, the lower end portion of the reinforcing plate 55 is also bent inward, and a fifth collar portion 55a protruding downward is formed at the inner end of the semi-cylindrical outer peripheral surface 52a.

  The operation of attaching the sealing member 50 having the above configuration will be described. The seal member 50 places the flat seal portion 51 on the cylinder head joint surface 10a, and places the protruding seal portion 52 into the recess 10b. At this time, the flange-shaped second and third flange portions 54 b and 54 c sandwich the wall surface forming the concave portion 10 b of the cylinder head 10 from both the inside and outside, and the protruding seal portion 52 is firmly attached on the concave portion 10. Further, at this time, the fifth collar portion 55a of the reinforcing plate 55 is located at a position where it abuts against the inner surface of the wall surface of the recess 10b of the cylinder head 10.

  After the seal member 50 is thus mounted on the joint surface 10a and the recess 10b of the cylinder head 10, the head cover 8 is placed thereon. At this time, the operator can easily perform the operation of placing the head cover 8 on the cylinder head 10 by pulling the first collar portion 54a made of an elastic material outward and pushing it. . When the head cover 8 is placed in this way, the linear protrusions 51 a and 53 a on the upper surface of the seal member 50 enter linear reception grooves (not shown) formed on the lower end surface of the head cover 8. Further, the fourth collar portions 55b and 55b are in abutting contact with the inner wall surface of the head cover 8, and the first collar portion 54a is in abutting contact with the outer wall surface. That is, the wall portion of the head cover 8 is located between the inner side and the outer side by the first flange portion 54a and the fourth flange portions 55b and 55b.

  In the state where the sealing member is sandwiched between the upper end surface of the cylinder head 10 and the lower end surface of the head cover 8 as described above, the concave portion 10 b is reliably sealed by the projecting seal portion 52. At this time, since the projecting seal portion 52 is configured integrally with the flat seal portion 51, even if the projecting seal portion 52 receives an external force, there is no possibility that the projecting seal portion 52 is dropped or loosened. In particular, since the fourth and fifth collar portions 55b and 55a formed by the reinforcing plate 55 are in abutment with the inner wall surfaces of the head cover 8 and the cylinder head 10, the projecting seal portion 52 reduces the internal pressure of the cam chain chamber 14. Even if it is received, there is no risk that it will fall off or loosen, and high sealing performance can be maintained.

1 is a front sectional view of an engine having a head structure according to an embodiment of the present invention. It is a front external view of the head part of the engine. It is side surface sectional drawing which shows the inside of the head part of the said engine. It is front sectional drawing which shows the inside of the head part of the said engine. It is a front view with the cylinder head single-piece | unit which comprises the said head part structure. It is a top view which shows a part of seal member used for the said head part structure. It is a front view which shows a part of seal member used for the said head part structure. It is sectional drawing which followed the said sealing member along arrow AA and BB of FIG.

Explanation of symbols

E Engine 1 Crankcase 2 Crankshaft 3 Connecting rod 4 Piston 5 Cylinder block 6 Cylinder liner 8 Head cover 10 Cylinder head 10a Joint surface 10b Recessed portion 14 Cam chain chamber 15 Mount portion 15a, 15b Mounting hole 20 Exhaust valve 25 Intake valve 29 Ignition plug 30 Cam mechanism 31 Cam shaft 32, 33 Rocker arm 35 Cam chain mechanism 36 Driven sprocket 37 Chain 50 Seal member 51 Flat seal part 52 Projection seal parts 54a, 54b, 54c First, second and third flange parts 55 Reinforcing plate 55b, 55a 4th and 5th brim parts

Claims (4)

A cylinder block (5) formed with a cylinder chamber into which the piston (4) is inserted;
A cylinder head (10) having a cam chain chamber (14) opened on the cylinder block (5) so as to cover the opening of the cylinder chamber on the side facing the piston head; and
A head cover (8) attached on the upper surface side end surface (10a ) of the cylinder head (10) so as to cover the cam chain chamber (14) ;
In clamped and sealed member (50) for sealing the junction of both the engine configured with a between the upper surface side end surface (10a) and said head cover (8) of said cylinder head (10),
A recess (10b) for processing a bearing portion of the camshaft (31 ) is formed on the upper surface side end surface (10a) of the cylinder head (10) ,
The seal member (50) is made of an elastic material that is sandwiched between the upper surface side end surface (10a) excluding the concave portion (10b ) of the cylinder head (10 ) and the lower end surface of the head cover (8) . flat seal portion (51), projecting sealing portion made of an elastic material is sandwiched between the lower end surface of the concave portion is attached closes the recess (10b) (10b) and said head cover (8) ( 52) and the configured integrally includes a metal reinforcing member on the inner surface of the projecting seal portion (52) (55) is provided integrally,
The concave portion (10b) is formed in a semicircular shape in a side view, and the protruding seal portion (52) is formed by forming the elastic material into a semicircular shape that fits into the concave portion (10b) , and the reinforcement The member (55) is formed in a semicircular shape corresponding to the shape of the protruding seal portion (52) ,
An outer collar portion (54a) projecting upward is formed at the outer end portion of the upper surface of the protruding seal portion (52) on the head cover side, and the protruding seal portion (52) is formed at the upper end portion on the head cover side of the reinforcing member. An inner collar portion (55b) protruding upward from the inner end portion of the upper surface of the upper surface is formed,
The protruding seal portion (52) is inserted into the recess (10b), and the seal member (50) is sandwiched between the upper end surface (10a) of the cylinder head (10 ) and the head cover (8). It is when the head portion structure of an engine in which the inner and outer flange portions (54a, 55b) is characterized by being configured to be positioned across the head cover (8) from the inner and outer. Claim 1, characterized in that pre-Symbol inner flange portion (55b) is positioned to be provided right pair so as to sandwich the outer flange portion on opposite sides of the outer flange portion in a side view (54a) (53a) The engine head structure described in 1. The width between the inner and outer ends in the plan view of the protruding seal portion (52) is larger than the width between the inner and outer ends in the plan view of the planar seal portion (51). The engine head structure described. The outer collar part (54a) formed on the projecting seal part (52) has a shape in which the amount of upward projection is larger than the inner collar part (55b) formed on the reinforcing member (55). The engine head part structure according to any one of claims 1 to 3, wherein the engine head part structure is provided.

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