JP4566071B2 - Internal combustion engine - Google Patents

Description

  The present invention relates to an improved structure of an internal combustion engine, and more particularly to an improved structure of an internal combustion engine characterized by an improved position restricting structure of a rocker arm.

The rocker arm that is rocked and supported by the conventional rocker arm shaft is pressed and urged in the axial direction by a spring to restrict the movement in the axial direction. In order to effectively control the movement of the rocker arm in the axial direction due to the vibration of the rocker, it is made by a spring with a large load set.
On the other hand, in the rocker arm having such a structure, it is necessary to move the rocker arm in the axial direction when replacing the shim provided on the upper seat of the valve in adjusting the tappet clearance. In order to move in the direction, it is necessary to compress and press the spring against a large spring load that is pressed and biased (see, for example, Patent Document 1).
JP 2004-316633 A (2nd page-3rd page, Fig. 3)

  As described above, Patent Document 1 discloses a structure in which a rocker arm swingably supported by a rocker arm shaft is pressed and urged in an axial direction by a spring for restricting movement in the axial direction. In this rocker arm structure, the biasing force by the spring of the rocker arm is made by the biasing spring having a large spring load in order to restrict the movement of the rocker arm in the axial direction due to the vibration during the engine operation described above.

  However, the pressing bias due to the large spring load in the rocker arm axial movement restriction makes it difficult for the rocker arm to move against the spring load when replacing the shim provided on the valve upper seat in the adjustment of the tappet clearance, for example. As a result, the workability of the shim replacement is reduced.

  In the situation as described above, the head cover is provided with a member that abuts the rocker arm and restricts the movement of the rocker arm in the axial direction, thereby eliminating the necessity of urging by the spring having the large spring load described above. However, it effectively regulates the axial movement of the rocker arm due to vibration during engine operation, and facilitates the axial movement of the rocker arm during work such as adjusting the tappet clearance, improving the workability of the adjustment work. An internal combustion engine having a rocker arm structure is provided.

The present invention relates to an improved structure of an internal combustion engine having a rocker arm structure for solving the above-mentioned problems. The invention according to claim 1 is formed by a cylinder head (3) and a head cover (4). And the rocker arm shaft (7, 7) provided in the valve chamber is supported so as to be swingable and movable in the axial direction, and is also axially supported by the elastic member (81, 82). In the internal combustion engine including the rocker arms (71, 72) biased by the first and second ends of the rocker arm shafts (7, 7), the one and the other of the rocker arm shafts (7, 7) provided on the cylinder head (3). The wall portions (3g, 3h) are respectively fitted and supported, and the rocker arms (71, 72) are supported by the rocker arm shafts (7, 7) so as to be movable and swingable in the axial direction, and the rocker arms (71 , 72) in the axial direction on the rocker arm shaft As pressure, the wall portion (3 g, 3h) between said rocker arm (71, 72), and the elastic member on the rocker arm shaft (7,7) (81, 82) is arranged, the head cover (4), said to restrict the axial movement caused by the axial pressing by the elastic member (81, 82) of the rocker arm in a state of being mounted to the cylinder head (3) (71, 72) A movement restricting member (4c, 4d) that abuts against the rocker arm (71, 72) is provided.

  The invention according to claim 2 is characterized in that the rocker arm has a projecting portion projecting in a radial direction, and the regulating member contacts the projecting portion.

Furthermore, the invention described in claim 3 is characterized in that the movement restricting member is formed integrally with the head cover and has a recessed portion with a tip portion recessed along the rocker arm shaft.
The invention described in claim 4 is characterized in that the movement restricting member is located between the head cover and the rocker arm shaft.

  The invention according to claim 1 of the present invention supports a valve operating chamber formed by a cylinder head and a head cover, and a rocker arm shaft provided in the valve operating chamber so as to be swingable and movable in the axial direction. In addition, in the internal combustion engine including a rocker arm biased in an axial direction by an elastic member, the head cover includes a regulating member that regulates the axial movement of the rocker arm in a state of being mounted on the cylinder head. Since it is provided, it is not necessary to increase the load of the elastic member while restricting the movement of the rocker arm in the axial direction, so that the rocker arm can be easily moved in the axial direction and the tappet clearance adjustment work can be easily performed. Can do.

  According to a second aspect of the present invention, in the first aspect of the present invention, the rocker arm has a protruding portion protruding in a radial direction, and the regulating member contacts the protruding portion. The rocker arm and the regulating member can be easily brought into contact with each other without being obstructed by other members.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the restricting member is formed integrally with the head cover, and a tip portion is recessed along the rocker arm shaft. Since it has a concave portion, it can be made inexpensive because it is integrally formed. Further, since the clearance between the restricting member and the rocker arm shaft can be as close as possible to the rocker arm shaft by the concave portion, the movement restriction of the rocker arm can be ensured.

  An embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows an upper structure of an internal combustion engine E of the present invention mounted on a motorcycle. The internal combustion engine E is an overhead valve type four-stroke cycle single cylinder internal combustion engine, and its main body part is partially Only a crankcase 1 consisting of a left case and a right case divided into left and right, a cylinder block 2 fixed to the upper part of the crankcase 1, a cylinder head 3 fixed to the upper part of the cylinder block 2, Further, it comprises a head cover 4 fixed to the head 3 so as to cover the upper part of the cylinder head 3, and a crankshaft 1 a, in which only a part of the crank portion is illustrated, is rotatably supported in the crankcase 1. ing.

  The crank pin 1b of the crankshaft 1a is pivotally supported by a large end 1c which is one end of the crankshaft 1a so that the connecting rod 1d is attached to the crankshaft 1a, and a piston is attached to the small end 1e which is the other end of the connecting rod 1d. The piston P is rocked and supported via a pin 1f. The piston P receives the combustion energy in a combustion chamber 3a, which will be described later, in a cylinder bore 2a provided in the cylinder block 2 and is pushed downward to rotate the crankshaft 1a via the connecting rod 1d. As the cylinder rotates, it reciprocates in the cylinder bore 2a.

  As described above, the cylinder block 2 is formed with the cylinder bore 2a and the combustion chamber 3a above the cylinder bore 2a. Further, the cylinder block 2 is provided with a vertical through-opening 2b for the camshaft 6 driving timing chain Tc and for circulation of cooling water. The water jacket 2c and the like are provided.

  The cylinder head 3 is provided with a combustion chamber 3a formed in cooperation with the above-described cylinder bore 2a at a joint portion with the cylinder block 2 below, and the ignition plug 3b is provided with an ignition portion in the combustion chamber 3a. 3 and the intake / exhaust openings 3e, 3f and the intake / exhaust openings 3e, 3f communicating with the intake / exhaust passages 3c, 3d as shown in FIG. Intake / exhaust valves 51 and 52 for opening and closing are provided, and there are four intake / exhaust openings 3e and 3f that are not clearly shown in the figure, but the two slightly larger openings are intake openings 3e, The slightly smaller two openings are exhaust openings 3f.

  Pushing action by pushing the valve stem upper ends 51c and 52c by the contact portions 71d1 and 72d1 of the arm portions 71d and 72d of the rocker arms 71 and 72 as the valve cams 61 and 62 rotate in the valve mechanism A described later. Apart from the time, the openings 3e, 3f are closed by the valve heads 51a, 52a for the upward movement of the valves 51, 52 via the valve stems 51b, 52b by the elastic force of the valve springs 51d, 52d.

  The above-described valve operating mechanism A for opening / closing the intake / exhaust valves 51 and 52 is provided at the upper part of the cylinder block 2. Although part of the valve mechanism A has already been described, the valve mechanism A generally contacts the camshaft 6, the two valve cams 61 and 62 provided on the camshaft 6, and the valve cams 61 and 62. Rocker arms 71 and 72 provided with rollers 71f and 72f on one side arm portions 71c and 72c, and abutting portions 71d1 and 72d1 on the other side arm portions 71d and 72d of the rocker arms 71 and 72, and the corresponding contact portions. It consists of intake / exhaust valves 51, 52 having valve stem upper ends 51c, 52c to be pushed.

  Referring to FIG. 1, a camshaft 6 is supported at an upper portion of a cylinder head 3 by a hole 3 g 1 of one wall portion 3 g which is a left wall portion of the head 3, which is the left wall portion of the head 3. At the same time, the other end, that is, the shaft portion 6c near the right end 6b in the figure is supported by the other wall 3h, which is the right wall in the figure of the head 3, via the ball bearing B. A sprocket 6e is attached to a shaft end 6d that is rotatably supported and protrudes from the other wall 3h, which is the right side wall of the cylinder head 3, and is attached to the sprocket 6e and the crankshaft 1a. The camshaft 6 is driven to rotate at 1/2 the number of rotations of the crankshaft 1a via a timing chain Tc spanned between sprockets (not shown).

  As can be understood by referring to FIGS. 1 to 3, the camshaft 6 (in FIG. 2) is arranged on the upper part of the camshaft 6 of the cylinder head 3 in parallel with the camshaft 6 and in a plan view (top view) in FIG. Are not shown), and two shafts 7 and 7 are provided at positions opposed to each other with respect to each other.

  These two shafts 7, 7 are rocker arm shafts 7 for mounting and supporting the rocker arms 71, 72, and one and the other walls of the cylinder head 3 whose upper and lower walls are shown in FIG. The openings 3g1 and 3h1 of the portions 3g and 3h are fitted and supported, respectively. The opening 3g1 of the one wall 3g is a blind hole, and the opening 3h1 of the other wall 3h is a through hole. The side opening end 3h11 is closed, that is, a hole that is closed to prevent the shaft 7 from being pulled out after the rocker arm shaft 7 is attached.

  The structure of the two wall openings 3g1 and 3h1 for supporting the rocker arm shaft 7 is such that the rocker arm shaft 7 is attached to the cylinder head 3 with the tip of the rocker arm shaft 7 inserted from the through hole 3h1 side on one wall. It is inserted and fitted into a blind hole which is a wall part opening 3g1 of the part 3g and positioned at an appropriate position, and thereafter the lower opening end 3h11 shown in the figure which is the shaft insertion side of the through hole 3h1 is closed by a closing member. It is the structure provided to be made by this.

  Rocker arms 71 and 72 are swingably supported at substantially central portions in the axial direction of the two rocker arm shafts 7 and 7, respectively. These rocker arms 71 and 72 are opposite to each other as described later. Since it is supported by the rocker arm shafts 7 and 7 in the direction, the one side end of the main body portions 71 a and 72 a, that is, the intake side rocker arm 71, is located between the one side end 71 a 1 and one wall portion 3 g of the cylinder head 3. It is pressed to one side in the axial direction by the interposed spring 81, that is, to the lower side in FIG.

  Further, the exhaust-side rocker arm 72 is pressed to one side in the axial direction, that is, the upper side in FIG. 2 by a spring 82 interposed between the one side end 72a1 and the other wall 3h of the cylinder head 3. . Therefore, the other side ends 71a2 and 72a2 of the rocker arm main body portions 71a and 72a are respectively connected to the other side wall portion of the cylinder head 3, that is, the other side end 71a2 of the main body portion of the intake side rocker arm 71 is the other wall portion 3h. The other end 72a2 of the main body portion of the exhaust side rocker arm 72 is in sliding contact with the side end 3g2 of the one wall portion 3g.

  As shown in FIG. 3, each of the two rocker arms 71 and 72 has a substantially arcuate shape in a side view, is slightly curved in a bow shape, and is a body portion that is a thick portion at a substantially central portion thereof. 71a and 72a are provided with holes 71b and 72b for swingable support to the rocker arm shaft 7. Thick arm portions 71c and 72c are respectively provided from one side of the main body portions 71a and 72a. It is extended.

  The thick one-side arm portions 71c, 72c extending from the main body portions 71a, 72a are slightly in the vertical direction of each of the main body portions 71a, 72a (the axial direction of the rocker arm shaft 7) in the plan view shown in FIG. 2, that is, in the plan view of FIG. 2, the rocker arm 71 is biased downward from the main body 71 a, and the rocker arm 72 is biased upward from the main body 72 a. Furthermore, they are narrowed in plan view in the vicinity of the tips of the arms 71c and 72c, and the narrow cams 71c1 and 72c1 are respectively provided with valve cams 61, Rollers 71f and 72f that come into contact with 62 are rotatably supported.

  Further, the thin arm portions 71d and 72d extending from the respective main body portions 71a and 72a to the other side of the two rocker arms 71 and 72 are separated from the base portions of the main body portions 71a and 72a in the plan view, respectively, and are arranged at the tips. The other side arm portions 71d and 72d are formed as a pair that is gradually separated from each other as they face, and the other side arm portions 71d and 72d that form these pairs are also in the vertical direction of the main body portions 71a and 72a in plan view of FIG. The ends of these arm portions 71d and 72d are formed as contact portions 71d1 and 72d1 to the valve stem upper ends 51c and 52c, respectively. However, the other side arm portions 71d and 72d forming the pair have different shapes in the two rocker arms 71 and 72.

  In the illustration of FIG. 2, the other side arm portions 72 d and 72 d forming a pair of the left exhaust side rocker arm 72 are substantially equiangular with respect to the base portion of the main body portion 72 a, more precisely with respect to the axis of the rocker arm shaft 7. The other side arm portions 71d and 71d form a pair of intake-side rocker arms 71 on the right side of the drawing. Are extended from the base portion of the main body 71a at different angles with respect to the axis of the rocker arm shaft 7 with the spacing interval increased toward the tip and in the same direction.

  The main body portions 71a and 72a of the two rocker arms 71 and 72 are respectively provided on the upper portions thereof along the axial direction of the rocker arm shaft 7 from the main body portions 71a and 72a so as to be understood in a plan view shown in FIG. The protrusions 71e and 72e, which are extensions of the rib-like ridges, extend from the ridges at the center of the main body parts 71a and 72a to the one axial end of the main body part, In addition, as can be understood from the side view shown in FIG. 1, it can be understood from the side view shown in FIG. 1, but protrudes from the main body portions 71 a and 72 a in the radial direction in this extending process, that is, upward. It extends in the direction.

  These projections 71e and 72e are located on the other side opposite to the position where the above-described arms 71c, 71d, 72c and 72d are biased to one side in the vertical direction of FIG. The protrusions 71e and 72e extend in the side space, and the movement restricting members (stoppers) 4c and 4d (tops 71e1 and 72e1 provided on the head cover 4 which will be described later are provided on the protrusions 71e and 72e above and in the axial direction of the shaft 7. Abutting on the rocker arms 71 and 72, the axial movement against the elastic force of the press springs 81 and 82 is suppressed.

  The rocker arms 71 and 72 swingably supported by the two rocker arm shafts 7 and 7 are positioned so that their directions are opposite to each other, that is, the tips 71c1 and 72c1 of the one-side arm portions 71c and 72c. The rollers 71f and 72f are on the inner side of the camshaft 6, and positioned so that the abutting portions 71d1 and 72d1 of the paired other arm portions 71d and 72d with the valve stem upper ends 51c and 52c are on the outer side. Thus, the rocker arm shafts 7 and 7 are supported in a rocking manner.

  The rotatable rollers 71f and 72f at the tips of the one-side arm portions 71c and 72c of the two rocker arms 71 and 72 are brought into contact with the valve cams 61 and 62 at predetermined intervals of the camshaft 6, respectively. In addition, the abutting portions 71d1, 71d1, 72d1, and 72d1 at the distal ends of the arm portions 71d, 71d, 72d, and 72d that form a pair, which are the other side arm portions 71d and 72d of the rocker arms 71 and 72, are respectively sucked and exhausted. The valve stems 51 and 52 are in contact with the valve stem upper ends 51c, 51c, 52c and 52c.

  That is, the tip contact portions 71d1 and 71d1 of the other side arm portions 71d and 71d that make a pair of the intake side rocker arm 71 are in contact with the stem upper ends 51c and 51c of the two intake side valves 51 and 51, respectively. The distal end abutting portions 72d1 and 72d1 of the other arm portions 72d and 72d that form a pair of the exhaust side rocker arms 72 are in contact with the stem upper ends 52c and 52c of the two exhaust side valves 52 and 52, respectively.

  The intake-side and exhaust-side rocker arms 71 and 72 are respectively connected to the valve-operating cams 61 and 62 of the rollers 71f and 72f at the distal ends of the one-side arms by the rotation of the valve-operating cams 61 and 62 accompanying the rotation of the camshaft 6. When the rollers 71f and 72f are pushed through the abutment, the rollers 71f and 72d swing around the mounting support portions to the rocker arm shafts 7 and 7, and the other side arm portions 71d, 71d, The two intake valves 51, 51 or the two exhaust valves 52, 52 are brought into contact with the valve stem upper ends 51c, 51c, 52c, 52c of the tip contact portions 71d1, 71d1, 72d1, 72d1 of 72d, 72d, respectively. Performs the operation for opening and closing.

  These intake / exhaust valves 51 and 52 are opened and closed by opening the valves 71f and 72f by the valve cams 61 and 62 and pushing the valves 51 and 52 closed by the valve springs 51d and 52d. This is done in cooperation with the spring force.

  As described above, the valve mechanism A above the cylinder head 3 is covered with the head cover 4 fixed to the cylinder head 3. As shown in FIG. 4, the head cover 4 is integrally formed with an upper wall portion 4a having a substantially rectangular outer shape in plan view, and a side wall portion 4b having a predetermined width extending substantially perpendicular to the wall portion 4a at the periphery thereof. Overall, it has a bowl-like shape with a predetermined depth. Therefore, the space surrounded by the upper part of the cylinder head 3, the head cover upper wall 4a, and the head cover side wall 4b forms a chamber (valve chamber) for the valve mechanism A.

  The head cover 4 is provided with a bolt hole 4e for attaching the cover 4 to the cylinder head 3, and the above-described 2 is formed on the inner surface of the head cover upper wall portion 4a, that is, the inner surface of the portion that forms the bowl-shaped substantial bottom surface. Two movement restricting members 4c and 4d are provided, and these movement restricting members 4c and 4d are formed as protrusions having a predetermined width protruding from the inner surface at a predetermined height, and the two protrusions have a predetermined distance from each other. It is arranged.

  As shown in FIGS. 4 to 6, the two movement restricting members 4c and 4d having a predetermined width have substantially the same height and the same width, and one movement restricting member 4c is provided on the head cover. The inner surface of the wall portion 4a is provided on the left side in the longitudinal direction of the plan view shown in FIG. 4 and slightly on the short side, and the other movement restricting member 4d is provided on the inner surface of the head cover upper wall portion 4a as shown in FIG. It is provided at the approximate center in the longitudinal direction in plan view and slightly above the short direction.

  Each of the movement restriction members 4 c and 4 d is provided at a position where one movement restriction member 4 c corresponds to one corresponding to the intake side rocker arm shaft 7 when the head cover 4 is attached to the cylinder head 3. In addition, the other movement restricting member 4d is a position corresponding to the other, that is, the exhaust-side rocker arm shaft 7. Accordingly, the movement restricting members 4c and 4d are respectively recessed recesses 4c1 and 4d1 (see FIGS. 3 and 5) that are recessed at the tips of the protrusions to avoid direct contact with the rocker arm shafts 7 and 7 when the head cover 4 is mounted. ) Is provided.

  The two movement restricting members 4c and 4d provided at the above-mentioned positions on the inner surface of the head cover upper wall 4a are respectively attached to the above-described two rocker arm shafts 7 and 7, respectively. The movement restricting members 4c and 4d are for suppressing the movement on the shafts 7 and 7, and the movement restricting members 4c and 4d are extension portions of the raised portions on the rocker arm main body portions 71a and 72a. The tips 71e1 and 72e1 of the protrusions 71e and 72e face each other with a slight gap (see FIG. 1).

  The internal combustion engine E according to the embodiment of the present invention generally has the above-described structure. When the internal combustion engine E is ignited by the fuel / air mixture supplied to the combustion chamber 3a, the fuel is explosively burned. Then, the piston P is pushed down by the combustion energy, and the pushing-down movement of the piston P rotates the crankshaft 1a via the connecting rod 1d, and the rotation of the crankshaft 1a pushes up the piston P via the connecting rod 1d. P reciprocates. The reciprocating motion of the piston P and the rotation of the crankshaft 1a open and close the intake valve 51 and the exhaust valve 52 through the rotation of the camshaft 6 in a predetermined order and timing synchronized with the reciprocating motion and the rotation. .

  In the above-described operation of the internal combustion engine E, the two valve cams 61 and 62 whose cam crests are displaced from each other in the rotational direction of the camshaft 6 are respectively one side of the two rocker arms 71 and 72. The one side arm portions 71c and 72c of the rocker arms 71 and 72 are brought into contact with the rollers 71f and 72f attached to the tips of the arm portions 71c and 72c, respectively, and the cams 61 and 62 are rotated by the rotation of the camshaft 6. Are pushed up at a predetermined timing, the rocker arms 71 and 72 are swung with the rocker arm shaft 7 as a rocking fulcrum, and the valve stem upper ends 51c and 52c are brought into contact with the abutting portions 71d1 and 72d1 of the other side arm portions 71d and 72d. Is pressed down to open and close the intake / exhaust valves 51 and 52 in a predetermined order and timing.

  When the rocker arms 71 and 72 are operated, the rocker arms 71 and 72 move against the elastic force of the pressing springs 81 and 82 by the moving force in the axial direction of the rocker arm shaft 7. The tips 71e1 and 72e1 of the projecting portions 71e and 72e, which are axially extending portions of the upper portions of the rocker arm main body portions 71a and 72a, are in contact with and regulated by the movement restricting members 4c and 4d which are the protruding portions of the inner surface of the head cover upper wall portion 4a. . Therefore, the movement against the elastic force of the springs 81 and 82 in the axial direction of the rocker arm shaft 7 in the rocking operation of the rocker arms 71 and 72 is suppressed almost completely.

  Since the embodiment of the present invention has the above-described structure, the following effects can be obtained.

  Since the head cover 4 includes the regulating members 4c and 4d that regulate axial movement against the elastic force of the springs 81 and 82 of the rocker arms 71 and 72 when mounted on the cylinder head 3, the rocker arms 71 and 72 are provided. The axial movement of the rocker arms 71 and 72 is effectively suppressed without setting the pressing load of the springs 81 and 82 to suppress the axial movement of the rocker more than necessary. It is kept within the proper range.

  The proper setting of the pressing load by the springs 81 and 82 eliminates the difficulty of moving the rocker arms 71 and 72 in the axial direction when adjusting the tappet clearance. Therefore, the movement of the rocker arms 71 and 72 during the adjustment is prevented. This facilitates the adjustment work and improves the workability. Moreover, since the rocker arms 71 and 72 can be moved on the rocker arm shafts 7 and 7 simply by removing the head cover 4, the movement for the shim adjustment is facilitated. Workability is improved.

  Since the rocker arms 71 and 72 have projections 71e and 72e that are directed in the axial direction and project in the radial direction, and the movement restricting members 4c and 4d are in contact with the projections 71e and 72e, the springs 81 and 82, etc. The rocker arms 71 and 72 and the restricting members 4c and 4d can be easily brought into contact with each other without being obstructed by other members, and thereby the rocker arms 71 and 72 are swung for operating the valves 51 and 52. Is stable with almost no movement (left-right movement) in the direction of the rocker arm shafts 7 and 7, and the noise and vibration of the engine E as well as the reliable operation for opening and closing the intake / exhaust valves 51 and 52 Also greatly contributes to reduction.

  The two movement restricting members 4c and 4d provided on the inner surface of the upper wall portion 4a of the head cover 4 are provided to face different rocker arm shafts 7 and 7, respectively, but the rocker arm shaft 7 of these movement restricting members 4c and 4d. , 7 are different axial positions of the rocker arm shafts 7 and 7, respectively, so that loads input to the movement restricting members 4c and 4d through the rocker arm shafts 7 and 7 are dispersed. The burden on the strength of the head cover 4 can be kept relatively low, and no measures for significantly increasing the strength of the head cover 4 are required.

  The movement restricting members 4c and 4d are formed integrally with the head cover 4 and the tip portions thereof have recesses 4c1 and 4d1 that are recessed along the rocker arm shafts 7 and 7. While ensuring the clearance between 4d and the rocker arm shafts 7 and 7, the rocker arm shafts 7 and 7 can be made as close as possible, and the movement restriction of the rocker arms 71 and 72 can be ensured. Furthermore, since it is integrally formed with the head cover 4, it can be provided at low cost.

  Although the movement restricting members 4c and 4d are formed integrally with the head cover 4 in the above-described embodiment, they can be configured separately, and the movement restricting members 4c and 4d are appropriately formed. It can also be formed of a member having elasticity.

It is a longitudinal cross-sectional view which shows the upper main structure part of the internal combustion engine of this invention. It is the top view by which a part of cylinder head in the state where the head cover of the present invention was removed was made into a cut surface. It is a sectional side view of the cylinder head part of this invention. It is a figure which shows the head cover of this invention, and is a figure which shows the inner surface side of a head cover. It is VV sectional drawing in FIG. It is VI-VI sectional drawing in FIG.

Explanation of symbols

3 ... Cylinder head, 4 ... Head cover, 4c, 4d ... Movement restricting member, 51, 52 ... Suction / exhaust valve, 51c, 52c ... Upper end of valve stem, 6 ... Camshaft , 61, 62 ... Valve cam, 7 ... Rocker arm shaft, 71, 72 ... Rocker arm, 71a, 72a ... Rocker arm body, 71c, 72c ... One side arm, 71d, 72d ... the other side arm, 71e, 72e ... projection, 71f, 72f ... roller, 81, 82 ... spring.

Claims (4)

A valve operating chamber formed by the cylinder head (3) and the head cover (4);
A rocker supported by a rocker arm shaft (7, 7) provided in the valve operating chamber so as to be swingable and movable in the axial direction, and biased in the axial direction by an elastic member (81, 82) In an internal combustion engine comprising arms (71, 72),
One and other end portions of the rocker arm shafts (7, 7) are fitted and supported on one and other wall portions (3g, 3h) provided on the cylinder head (3), respectively.
The rocker arm (71, 72) is supported on the rocker arm shaft (7, 7) so as to be movable and swingable in the axial direction,
The rocker arm (71, 72) is pressed between the wall (3g, 3h) and the rocker arm (71, 72) and the rocker arm shaft (7 , 7) and the elastic member (81, 82) is disposed thereon,
Said head cover (4) so as to regulate the axial movement caused by the axial pressing by the elastic member (81, 82) of said rocker arm in a state of being mounted on the cylinder head (3) (71, 72) An internal combustion engine comprising a movement restricting member (4c, 4d ) in contact with the rocker arm (71, 72) . The rocker arms (71, 72) have protrusions (71e, 72e) protruding in the radial direction, and the movement restricting members (4c, 4d) are in contact with the protrusions (71e, 72e). The internal combustion engine according to claim 1, wherein The movement restricting member (4c, 4d) is formed integrally with the head cover (4) and has a recessed portion (4c1, 4d1) whose tip is recessed along the rocker arm shaft (7, 7). The internal combustion engine according to claim 1 or 2, characterized in that. The movement restricting member (4c, 4d) is located between the head cover (4) and the rocker arm shaft (7, 7). Internal combustion engine.

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