JP5353115B2 - Engine valve gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve gear for engine capable of restricting eccentric wear of sliding surfaces of a cam and a rocker arm by improving rigidity of a cylinder head and preventing deflection of a rocker shaft. <P>SOLUTION: A cylinder head 22 comprises an intake cam shaft 37, an exhaust cam shaft 39, an intake rocker shaft 41, an intake rocker arm 42, an exhaust rocker shaft 43, and an exhaust rocker arm 44. The intake rocker shaft 41 and the exhaust rocker shaft 43 are provided outside of an area A between the intake camshaft 37 and the exhaust cam shaft 39. The cylinder head 22 is provided with a rocker shaft both end shaft support parts 61a and 61b for supporting each of the intake rocker shaft 41 and the exhaust rocker shaft 43 in both ends thereof and rocker shaft intermediate shaft support parts 62a and 62b for supporting them in an intermediate part thereof. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a valve operating apparatus for an engine mounted on a motorcycle.

  Generally, an engine mounted on a motorcycle includes a cylinder head having an intake valve and an exhaust valve.

  The cylinder head includes a valve operating device that drives an intake valve and an exhaust valve. One of the valve operating devices is a DOHC (Double Over Head Camshaft), a cam shaft for an intake valve, a cam shaft for an exhaust valve, and a cam. Rocker arm for intake valve and exhaust valve for swinging the valve by pivoting the shaft and opening and closing the valve, rocker shaft for intake valve and rocker shaft for exhaust valve that pivotably support the rocker arm There is known a rocker arm type valve gear including the above.

  In a rocker arm type valve operating device, a configuration is known in which a rocker shaft is disposed outside a region surrounded by an intake valve cam shaft and an exhaust valve cam shaft as viewed in the direction of the cylinder center axis of the engine. .

Here, in a valve operating system for an engine provided with two intake valves and exhaust valves per cylinder, two rocker arms can swing freely on a rocker shaft for an intake valve and a rocker shaft for an exhaust valve, respectively. Provided. Both end portions of each rocker shaft are supported by end shaft support portions of the cylinder head. A rocker arm side spring is loosely fitted to an intermediate portion of the rocker shaft sandwiched between the two rocker arms. Each rocker arm is biased to the end shaft support by a rocker arm side spring. (For example, patent document 1).
Japanese Utility Model Publication No. 02-78702

  The rocker arm of the conventional valve gear is pivotally supported by the cylinder head only at both ends. On the other hand, the intermediate part of the rocker shaft sandwiched between the two rocker arms is not pivotally supported by the cylinder head. That is, the rocker shaft has a relatively long interval between the support positions, and has a low rigidity. Then, the rocker shaft bends greatly, and the rocker arm is swung so that the rocker arm is twisted, and mechanical loss increases, and the sliding surface between the cam and the rocker arm and the sliding surface between the rocker arm and the tappet shim Unevenly worn out. On the other hand, even if the rigidity of the cylinder head is lowered, the support rigidity of the rocker shaft is lowered and the rocker arm is swung so as to be twisted. Uneven wear occurs.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an engine valve device that can improve the rigidity of a cylinder head and prevent deflection of a rocker shaft and suppress uneven wear of a sliding surface of a cam or a rocker arm.

In order to solve the above-mentioned problems, in the present invention, a cylinder head of a single cylinder engine, two intake valves and exhaust valves respectively provided in the cylinder head, and the intake air provided in the cylinder head and rotatably supported by the cylinder head. A camshaft for the valve and a camshaft for the exhaust valve, and a rocker shaft for the intake valve and the exhaust valve for the exhaust valve, which are disposed outside the region between the camshafts provided on the cylinder head. A rocker shaft, two rocker arms for the intake valve and two rocker arms for the exhaust valve, which are pivotally supported by the rocker shaft, and rocker arms provided on the camshaft. A cam for the intake valve and a cam for the exhaust valve; An end shaft support portion that supports both ends of the car shaft, and an intermediate shaft support portion that supports an intermediate portion of the rocker shaft sandwiched between the two rocker arms. And a cam shaft support portion that pivotally supports the cam shaft, the cam shaft support portion and the intermediate shaft support portion are connected to each other, and the intermediate shaft support portion extends to the side surface of each rocker arm. The cylinder head includes a side wall for defining the cam chain tunnel at one axial end of the cam shaft, and a cam chain that supports the cam shaft on the opposite side of the side wall with the cam chain tunnel interposed therebetween. A camshaft side camshaft support portion, and the cam chain side camshaft support portion is coupled to each other at a split surface passing through the shaft center of the camshaft and separate from the cylinder head The lower housing is mainly composed of a lower housing and an upper housing, and the lower housing has an abutting surface that abuts on one end surface of the rocker shaft inserted from an insertion port formed in the side wall portion and performs a retaining function. characterized by comprising.

  ADVANTAGE OF THE INVENTION According to this invention, while improving the rigidity of a cylinder head, the valve operating apparatus of an engine which can prevent the deflection | deviation of a rocker shaft and can suppress the uneven wear of the sliding surface of a cam or a rocker arm can be provided.

  An embodiment of a valve operating apparatus for an engine according to the present invention will be described with reference to FIGS.

  FIG. 1 is a right side view showing an example of a motorcycle equipped with a valve operating apparatus for an engine according to the present invention.

  As shown in FIG. 1, the motorcycle 1 includes a body frame 2. A front fork 4 that is steered by a bar handle 3 is provided at the front of the body frame 2. A front wheel 6 covered with a front fender 5 is suspended from a lower end portion of the front fork 4. A disc brake 7 is provided on the front wheel 6.

  On the other hand, a rear fender 8 is provided at the rear portion of the vehicle body frame 2. A rear wheel 10 is suspended by a swing arm 9 below the rear fender 8. A rear suspension (not shown) is provided between the vehicle body frame 2 and the swing arm 9.

  A fuel tank 11 is placed on the upper part of the vehicle body frame 2. A seat 12 is extended at a position that covers the fuel tank 11 and covers a part of the rear fender 8.

  An engine 13 is mounted in the central internal space of the body frame 2. A radiator 14 is disposed obliquely above and forward of the engine 13.

  The engine 13 is a DOHC engine, and includes a cylinder head 22 and a head cover 23 above the cylinder block 21.

  FIG. 2 is a cross-sectional view showing a cylinder block provided with a valve operating apparatus for an engine according to the present invention. 2 is a cross-sectional view taken along the line II-II in FIG. 3, and is a view in which an upper housing described later is omitted.

  As shown in FIG. 2, a combustion chamber 25 formed between the cylinder head 21 and the cylinder block 21 is provided below the cylinder head 22. The combustion chamber 25 has two intake ports 27 (only one intake port 27 is shown in FIG. 2) and two exhaust ports 28 (only one exhaust port 28 is shown in FIG. 2). .). The intake port 27 communicates the inside of the combustion chamber 25 with the intake passage 29. The exhaust port 28 communicates the inside of the combustion chamber 25 with the exhaust passage 30. Valve seats 32 and 33 are provided in the intake port 27 and the exhaust port 28, respectively.

  The cylinder head 22 includes two intake valves 35, two exhaust valves 36, an intake camshaft 37 (an intake valve camshaft), and two intake valves provided on the intake camshaft 37. Cam 38 (intake valve cam), exhaust camshaft 39 (exhaust valve camshaft), and two exhaust cams 40 (exhaust valve cam) provided on the exhaust camshaft 39 , An intake rocker shaft 41 (an intake valve rocker shaft), two intake rocker arms 42 (an intake valve rocker arm) pivotally supported by the intake rocker shaft 41, and an exhaust rocker A shaft 43 (exhaust valve rocker shaft) and two exhaust rocker arms 44 pivotally supported by the exhaust rocker shaft 43 (exhaust valve rocker arm) ) And a.

  The intake valve 35 opens and closes the intake port 27. The intake valve 35 includes an umbrella portion 35a and a stem 35b extending substantially upward from the umbrella portion 35a. The umbrella portion 35 a is disposed in contact with the valve seat 32 of the intake port 27. The stem 35 b is slidably inserted into a stem guide 47 provided in the cylinder head 22.

  A spring retainer 48 is provided at the upper end of the stem 35 b of the intake valve 35, and a spring seat 49 supported by the cylinder head 22 is loosely fitted to the stem guide 47. A valve spring 50 is sandwiched between the spring retainer 48 and the spring seat 49. The valve spring 50 urges the intake valve 35 to close via the spring retainer 48.

  The exhaust valve 36 opens and closes the exhaust port 28. The exhaust valve 36 includes an umbrella portion 36a and a stem 36b extending substantially upward from the umbrella portion 36a. The umbrella portion 36 a is disposed in contact with the valve seat 33 of the exhaust port 28. The stem 36 b is slidably inserted into a stem guide 52 provided in the cylinder head 22. When the cylinder head 22 is viewed from the side, the stems 35b and 36b of the intake valve 35 and the exhaust valve 36 are arranged in a substantially V shape.

  A spring retainer 53 is provided at the upper end of the stem 36 b of the exhaust valve 36, and a spring seat 54 supported by the cylinder head 22 is loosely fitted to the stem guide 52. A valve spring 55 is sandwiched between the spring retainer 53 and the spring seat 54. The valve spring 55 urges the exhaust valve 36 to close via the spring retainer 53.

  The intake camshaft 37 is provided above the intake valve 35. The axis of the intake camshaft 37 is disposed on a substantially extended line of the stem 35 b of the intake valve 35.

  The exhaust camshaft 39 is provided above the exhaust valve 36. The shaft core of the exhaust cam shaft 39 is disposed on a substantially extended line of the stem 36 b of the exhaust valve 36.

  The intake camshaft 37 and the exhaust camshaft 39 are arranged so that their axial centers are substantially parallel to each other.

  The two intake cams 38 are provided at appropriate positions on the intake cam shaft 37 so as to correspond to the respective intake valves 35. The intake cam 38 is rotated integrally with the intake cam shaft 37.

  The two exhaust cams 40 are provided at appropriate positions on the exhaust cam shaft 39 so as to correspond to the respective exhaust valves 36. The exhaust cam 40 is rotated integrally with the exhaust cam shaft 39.

  The intake rocker shaft 41 is provided outside the region A sandwiched between the intake camshaft 37 and the exhaust camshaft 39. The intake rocker shaft 41 is disposed below the intake camshaft 37.

  The exhaust rocker shaft 43 is provided outside the region A. Further, the exhaust rocker shaft 43 is disposed below the exhaust cam shaft 39.

  The intake rocker shaft 41 and the exhaust rocker shaft 43 are formed in a tubular shape and have an oil passage 57 therein.

  The intake camshaft 37, the exhaust camshaft 39, the intake rocker shaft 41, and the exhaust rocker shaft 43 are arranged so that their axial centers are substantially parallel to each other.

  The two intake rocker arms 42 are provided at appropriate positions on the intake rocker shaft 41 so as to correspond to the respective intake valves 35. An intake cam 38 is disposed above the intake rocker arm 42, and a stem 35 b of the intake valve 35 is disposed below the intake rocker arm 42. The upper surface of the intake rocker arm 42 is in contact with the peripheral surface of the intake cam 38, and the lower surface of the intake rocker arm 42 is in contact with a shim 58 provided at the upper end of the stem 35b. That is, the intake rocker arm 42 is disposed between the intake cam 38 and the stem 35b.

  The two exhaust rocker arms 44 are provided at appropriate positions on the exhaust rocker shaft 43 so as to correspond to the respective exhaust valves 36. An exhaust cam 40 is disposed above the exhaust rocker arm 44, and a stem 36 b of the exhaust valve 36 is disposed below the exhaust rocker arm 44. The upper surface of the exhaust rocker arm 44 is in contact with the peripheral surface of the exhaust cam 40, and the lower surface of the exhaust rocker arm 44 is in contact with a shim 59 provided at the upper end of the stem 36b. That is, the exhaust rocker arm 44 is disposed between the exhaust cam 40 and the stem 36b.

  The intake camshaft 37 is rotated in a direction in which the cam nose of the intake cam 38 slides from the free end side of the intake rocker arm 42 to the swing shaft side (intake rocker shaft 41) (FIG. 2). Middle, solid arrow Ri direction). Further, the exhaust camshaft 39 is rotated in a direction in which the cam nose of the exhaust cam 40 is slid from the swinging shaft side (exhaust rocker shaft 43) of the exhaust rocker arm 44 to the free end side (FIG. 2). Middle, solid arrow Ro direction).

  The intake cam 38 rotates integrally with the intake cam shaft 37 and opens the intake valve 35 via the intake rocker arm 42 pivotally supported by the intake rocker shaft 41. On the other hand, the exhaust cam 40 rotates integrally with the exhaust camshaft 39 and opens the exhaust valve 36 via the exhaust rocker arm 44 pivotally supported by the exhaust rocker shaft 43.

  FIG. 3 and FIG. 4 are plan views showing a cylinder block provided with an engine valve gear according to the present invention.

  FIG. 5 is a cross-sectional view taken along the line V-V in FIG. 3, and is a cross-sectional view showing a cylinder block provided with a valve operating apparatus for an engine according to the present invention.

  FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 3 and is a cross-sectional view showing a cylinder block provided with the valve operating apparatus for an engine according to the present invention.

  FIG. 7 is a cross-sectional view taken along the line VII-VII in FIG. 3, and is an exploded cross-sectional view showing a cylinder block provided with the valve gear for an engine according to the present invention.

  FIG. 3 is a view in which an upper housing, an intake camshaft 37, an intake cam 38, an exhaust camshaft 39, and an exhaust cam 40, which will be described later, are omitted. FIG. 5 is a view in which an upper housing described later is omitted.

  As shown in FIGS. 3 to 7, the cylinder head 22 includes rocker shaft both-end shaft support portions 61 a and 61 b that are supported at both ends of the intake rocker shaft 41 and the exhaust rocker shaft 43, and intermediate portions thereof. Rocker shaft intermediate shaft support portions 62a and 62b, on which the portions are supported, are provided. The rocker shaft intermediate shaft support portion 62 a is positioned at an intermediate portion of the intake rocker shaft 41 sandwiched between the two intake rocker arms 42. On the other hand, the rocker shaft intermediate shaft support portion 62 b is disposed at an intermediate portion of the exhaust rocker shaft 43 sandwiched between the two exhaust rocker arms 44.

  The rocker shaft both-ends pivot support portion 61 a extends to the side surface of the intake rocker arm 42 that is pivotally supported by the intake rocker shaft 41. Further, the rocker shaft intermediate shaft support portion 62 a also extends to the side surface of the intake rocker arm 42 that is pivotally supported by the intake rocker shaft 41. It should be noted that the intake rocker arm 42 swings between the rocker shaft both ends pivot support 61a and the side surface of the intake rocker arm 42 and between the rocker shaft intermediate shaft support 62a and the side surface of the intake rocker arm 42. A minute gap that is movable is formed.

  On the other hand, both end portions 61 b of the rocker shaft are extended to the side surface of the exhaust rocker arm 44 that is pivotally supported by the exhaust rocker shaft 43. The rocker shaft intermediate shaft support portion 62 b also extends to the side surface of the exhaust rocker arm 44 that is pivotally supported by the exhaust rocker shaft 43. It should be noted that the exhaust rocker arm 44 swings between the rocker shaft both ends shaft support 61b and the side surface of the exhaust rocker arm 44, and between the rocker shaft intermediate shaft support portion 62b and the side surface of the exhaust rocker arm 44. A minute gap that is movable is formed.

  That is, each intake rocker arm 42 is supported at both ends by an intake rocker shaft 41, which is a swinging shaft thereof, with the rocker shaft both-end shaft support portion 61a and the rocker shaft intermediate shaft support portion 62a as support positions. On the other hand, each of the exhaust rocker arms 44 is also supported at both ends by the exhaust rocker shaft 43, which is a swinging shaft thereof, with the rocker shaft both-end shaft support portions 61b and the rocker shaft intermediate shaft support portion 62b as support positions.

  Notches 64 a and 64 b are formed at the edges of the rocker shaft both-end shaft support portions 61 a and 61 b and the rocker shaft intermediate shaft support portions 62 a and 62 b so as to face the side surfaces of the intake rocker shaft 41 or the exhaust rocker shaft 43. . The notch 64 a on the intake rocker shaft 41 side is disposed to face the intake camshaft 37. Further, the notch 64a is cut out wider than the intake cam 38 with the intake rocker arm 42 interposed therebetween. On the other hand, the notch 64 b on the exhaust rocker shaft 43 side is disposed to face the exhaust camshaft 39. Further, the notch 64 b is cut wider than the exhaust cam 40 with the exhaust rocker arm 44 interposed therebetween.

  The intake rocker shaft 41 and the exhaust rocker shaft 43 have a communication hole 65 communicated with the oil passage 57 so as to correspond to the notches 64a and 64b. The communication hole 65 allows the notches 64 a and 64 b to communicate with the oil passage 57.

  Of the side surfaces of the cylinder head 22, one side surface portion 22 a that intersects the longitudinal axis direction of the intake rocker shaft 41 and the exhaust rocker shaft 43 is an insertion port 67 of the intake rocker shaft 41 or the exhaust rocker shaft 43. Have The insertion port 67 is closed by a retaining bolt 68 of the intake rocker shaft 41 or the exhaust rocker shaft 43. On the other hand, of the side surfaces of the cylinder head 22, the other side surface portion 22 b (side wall portion) intersecting the longitudinal axis direction of the intake rocker shaft 41 and the exhaust rocker shaft 43 is penetrated in the vertical direction of the cylinder head 22. A cam chain tunnel 69 is provided. The side surface portion 22 b defines a cam chain tunnel 69 at one axial end of the intake camshaft 37 and the exhaust camshaft 39.

  The cylinder head 22 has an intake camshaft 37 and an exhaust camshaft 39 extending from a portion sandwiched between two intake rocker arms 42 to a portion sandwiched between two exhaust rocker arms 44. A supporting cam shaft support 71 is formed. The cam shaft support portion 71 and the rocker shaft intermediate shaft support portion 62a are connected to each other, and the cam shaft support portion 71 and the rocker shaft intermediate shaft support portion 62b are connected to each other. An upper housing 72 is fastened to the cam shaft support portion 71. The central portion of the cam shaft support portion 71 and the upper housing 72 has a plug insertion hole 73. A dividing surface between the upper housing 72 and the cam shaft support portion 71 is disposed on substantially the same surface as a dividing surface between the cylinder head 22 and the head cover 23.

  The cam shaft support portion 71 and the upper housing 72 are formed with bearing portions 74 a and 74 b for the intake cam shaft 37 or the exhaust cam shaft 39. Bolt holes 75 for fastening the upper housing 72 are formed in the vicinity of the bearing portions 74a and 74b. Out of the bolt holes 75, the outer side bolt holes 75 a located in the vicinity of the intake rocker shaft 41 or the exhaust rocker shaft 43 are over the intake rocker shaft 41 or the exhaust rocker shaft 43 in the bolt insertion direction. Wrapped and placed. The bolt hole 75a is not overlapped by the fastening bolt 76 inserted into the bolt hole 75a in the longitudinal direction of the intake rocker shaft 41 or the exhaust rocker shaft 43, and the fastening bolt 76 and the intake rocker shaft 41 are not overlapped. Alternatively, the exhaust rocker shaft 43 is not interfered with each other. On the other hand, in the bolt hole 75, the inner side bolt hole 75b located in the vicinity of the plug insertion hole 73 is communicated with the oil introduction groove 78 formed in the bearing portion 74a or the bearing portion 74b.

  At the edge of the cam chain tunnel 69 of the cylinder head 22, an upper bearing housing 80 (upper cam housing) on which an intake cam shaft 37 and an exhaust cam shaft 39 are pivotally supported, and a lower bearing housing 81 (lower cam housing, A separate lower housing). The split surfaces of the upper bearing housing 80 and the lower bearing housing 81 are arranged on substantially the same plane as the split surfaces of the cylinder head 22 and the head cover 23, and the shaft centers of the intake cam shaft 37 and the exhaust cam shaft 39 are centered. Pass through. The upper bearing housing 80 and the lower bearing housing 81 are provided with a bearing 82a in which the intake camshaft 37 is rotatably held and a bearing 82b in which the exhaust camshaft 39 is rotatably held. The upper bearing housing 80, the lower bearing housing 81, the bearing 82a, and the bearing 82b are cams that support the intake camshaft 37 and the exhaust camshaft 39 on the opposite side of the side surface portion 22b across the cam chain tunnel 69. Configures the chain side cam shaft support. A gap S is formed between the lower surface of the lower bearing housing 81 and the cylinder head 22. A head bolt seating surface 83 of a head bolt (not shown) for fastening the cylinder head 22 to the cylinder block 21 is formed below the lower bearing housing 81.

  The upper bearing housing 80 is formed integrally with the upper housing 72.

  The intake camshaft 37 is rotatably held at two locations, a bearing portion 74a and a bearing 82a. On the other hand, the exhaust camshaft 39 is rotatably held at two locations of a bearing portion 74b and a bearing 82b.

  An intake cam driven sprocket 85 is provided at the end of the intake camshaft 37 that is disposed on the cam chain tunnel 69 side. On the other hand, an exhaust cam driven sprocket 86 is provided at the end of the exhaust camshaft 39 disposed on the cam chain tunnel 69 side. A cam chain 87 is wound around the intake cam driven sprocket 85, the exhaust cam driven sprocket 86, and the crankshaft (not shown) of the engine 13. The cam chain 87 transmits the rotation of the crankshaft to the intake camshaft 37 and the exhaust camshaft 39 to rotate the intake camshaft 37 and the exhaust camshaft 39. The intake camshaft 37 and the exhaust camshaft 39 are synchronized with the rotation of the crankshaft via the intake cam driven sprocket 85, the exhaust cam driven sprocket 86, and the cam chain 87, and have a cycle twice that of the intake cam driven sprocket 85. It is rotated.

  Of the end portions of the intake camshaft 37, one of the intake cams 38 is disposed at the free end portion disposed on the side far from the cam chain tunnel 69, and among the end portions of the exhaust camshaft 39. One of the exhaust cams 40 is disposed at the free end disposed on the side far from the cam chain tunnel 69.

  The intake cam 38 is formed wider than the intake rocker arm 42. When the intake cam 38 is rotated, the cam nose enters the notch 64a and overlaps the rocker shaft both-end shaft support portion 61a and the rocker shaft intermediate shaft support portion 62a in the longitudinal direction of the intake rocker shaft 41. . On the other hand, the exhaust cam 40 is formed wider than the exhaust rocker arm 44. When the exhaust cam 40 is rotated, the cam nose enters the notch 64b and overlaps the rocker shaft both-end shaft support portion 61b and the rocker shaft intermediate shaft support portion 62b in the longitudinal direction of the exhaust rocker shaft 43. .

  Here, the cylinder head 22 has a supply path 88 through which oil is guided from the cylinder block 21 to the upper housing 72. The oil guided to the supply path 88 is guided to the bolt hole 75 b through an oil passage (not shown) formed in the upper housing 72. Part of the oil guided to the bolt hole 75 b is guided to the oil introduction groove 78. The oil guided to the oil introduction groove 78 lubricates the sliding portion between the intake camshaft 37 and the bearing portion 74a or the sliding portion between the exhaust camshaft 39 and the bearing portion 74b. Further, the other part of the oil guided to the bolt hole 75b is guided to the upper bearing housing 80 through an oil communication path (not shown). Part of the oil guided to the upper bearing housing 80 lubricates the bearings 82a and 82b. The other part of the oil guided to the upper bearing housing 80 is guided to the oil passage 57 of the intake rocker shaft 41 and the exhaust rocker shaft 43 through an oil passage (not shown) formed in the lower bearing housing 81. Is done. The oil guided to the oil passage 57 is supplied to the sliding surfaces of the intake cam 38 and the exhaust cam 40 from the notches 64 a and 64 b through the communication hole 65. The oil that has lubricated the bearing portion 74a, the bearing portion 74b, the bearings 82a and 82b, the intake cam 38, and the exhaust cam 40 passes through the clearance S between the lower surface of the lower bearing housing 81 and the cylinder head 22, It flows into the cam chain tunnel 69 and is returned to the crankcase.

  8 and 9 are plan views showing another example of a cylinder block provided with the valve operating apparatus for an engine according to the present invention.

  As shown in FIGS. 8 and 9, the cylinder head 22 </ b> A intersects the longitudinal axis direction of the intake rocker shaft 41 and the exhaust rocker shaft 43 on the side surface, and a cam chain tunnel 69 is formed. The other side surface portion 22b has an insertion port 90 through which the intake rocker shaft 41 or the exhaust rocker shaft 43 is inserted. The intake rocker shaft 41 or the exhaust rocker shaft 43 is inserted from the insertion opening 90 into the rocker shaft both-end shaft support portions 61a and 61b and the rocker shaft intermediate shaft support portions 62a and 62b. The lower bearing housing 81 has contact surfaces that are in contact with the end surfaces of the intake rocker shaft 41 and the exhaust rocker shaft 43 on the cam chain tunnel 69 side. That is, the intake rocker shaft 41 and the exhaust rocker shaft 43 are restrained by the lower bearing housing 81 and are prevented from coming off.

  According to the cylinder head 22A, the intake rocker shaft 41 or the exhaust rocker shaft 43 is inserted into the cylinder head 22 and then the lower bearing housing 81 is assembled to the cylinder head 22A. Since the shaft 41 or the exhaust rocker shaft 43 is prevented from being removed, a retaining bolt or the like is not required.

  The insertion port 90 is closed by a closing bolt 91 after the intake rocker shaft 41 and the exhaust rocker shaft 43 are inserted.

  According to the valve operating apparatus of the engine provided in the cylinder heads 22 and 22A of the engine 13 according to the present embodiment, the rocker shaft intermediate shaft support portions 62a and 62b are provided in the cylinder head 22, so that each intake rocker Since both the swing shaft of the arm 42 and the swing shaft of each exhaust rocker arm 44 can be stably supported, the deflection of the intake rocker shaft 41 and the exhaust rocker shaft 43 can be prevented. Further, the rocker shaft intermediate shaft support portions 62a and 62b are connected to the cam shaft support portion 71 on which the intake cam shaft 37 and the exhaust cam shaft 39 are supported, thereby improving the rigidity of the cylinder heads 22 and 22A. Further, the support rigidity of the intake rocker shaft 41 and the exhaust rocker shaft 43 is also improved. Therefore, the deflection of the intake rocker shaft 41 and the exhaust rocker shaft 43 is reduced, and uneven wear on the sliding surfaces of the intake rocker arm 42, the exhaust rocker arm 44, the intake cam 38, and the exhaust cam 40 is It is extremely suppressed and mechanical loss is reduced.

  Further, according to the valve operating apparatus of the engine provided in the cylinder heads 22 and 22A of the engine 13 according to the present embodiment, the intake rocker arm 42 and the exhaust rocker arm 44 are provided with the rocker shaft both-end shaft support portions 61a and 61b and The intake rocker shaft 41 and the exhaust rocker shaft 43 are positioned in the longitudinal direction by the opposing side surfaces of the rocker shaft intermediate shaft support portions 62a and 62b. Therefore, unlike the conventional valve operating device, a positioning spring that biases the rocker arm in the longitudinal direction of the rocker shaft is not required, and the intake rocker arm 42 and the exhaust rocker arm 44 are smoothly swung.

  Furthermore, according to the valve operating apparatus of the engine provided in the cylinder heads 22 and 22A of the engine 13 according to the present embodiment, since the notches 64a and 64b are provided, the intake cam 38 and the exhaust cam 40 are rotated. The cam nose does not interfere with the rocker shaft both end shaft support portions 61a and 61b and the rocker shaft intermediate shaft support portions 62a and 62b, and the distance between the intake camshaft 37 and the intake rocker shaft 41 and the exhaust camshaft 39 The separation distance from the exhaust rocker shaft 43 can be reduced as much as possible. Therefore, the cylinder head 22 can be reduced in size.

  Furthermore, according to the engine valve gear provided in the cylinder heads 22 and 22A of the engine 13 according to the present embodiment, the intake passage rocker arm 42 has the oil passage 57 communicated with the notches 64a and 64b. Since oil can be supplied from the notches 64a and 64b to the sliding surface between the intake cam 38 and the sliding surface between the exhaust rocker arm 44 and the exhaust cam 40, the valve The lubrication performance of the device can be improved.

  In particular, since the intake rocker shaft 41 is disposed outwardly with respect to the intake cam shaft 37, the cam nose of the intake cam 38 pushes down the intake rocker arm 42 on the sliding surface of the intake cam 38. Immediately after the oil is supplied. Here, since the intake cam 38 swings the intake rocker arm 42 so as to wind the free end side of the intake rocker arm 42, friction generated on the sliding surfaces of the intake cam 38 and the intake rocker arm 42. The heat is great. The notch 64a according to this embodiment can efficiently cool the sliding surface of the intake cam 38 by supplying oil to the sliding surface of the intake cam 38 immediately after the intake rocker arm 42 is pushed down. .

  On the other hand, since the exhaust rocker shaft 43 is disposed outward with respect to the exhaust cam shaft 39, the cam nose of the exhaust cam 40 pushes down the exhaust rocker arm 44 on the sliding surface of the exhaust cam 40. Immediately before, oil is supplied. Here, since the exhaust valve 36 is exposed to the exhaust gas, the temperature is higher than that of the intake valve 35, so that the exhaust cam 40 passes through the exhaust rocker arm 44 while the exhaust valve 36 is being pushed down. Due to heat transfer from the exhaust valve 36, the temperature tends to increase. The notch 64b according to the present embodiment supplies oil to the sliding surface of the exhaust cam 40 immediately before receiving heat transfer, so that an oil film is reliably formed on the sliding surface of the exhaust cam 40. This makes it difficult for the cam 40 to receive heat.

  Further, according to the valve operating apparatus of the engine provided in the cylinder heads 22 and 22A of the engine 13 according to the present embodiment, the bolt hole 75a disposed in the vicinity of the intake rocker shaft 41 or the exhaust rocker shaft 43 includes: Since it is disposed so as to overlap the intake rocker shaft 41 or the exhaust rocker shaft 43 in the bolt insertion direction, the separation distance between the intake camshaft 37 and the intake rocker shaft 41 in the plan view of the cylinder head 22. , And the distance between the exhaust camshaft 39 and the exhaust rocker shaft 43 can be reduced as much as possible. Therefore, the cylinder head 22 can be reduced in size.

  In particular, an intake rocker shaft 41 and an exhaust rocker shaft 43 are disposed outside a region A surrounded by the intake camshaft 37 and the exhaust camshaft 39, and the intake camshaft 37 and the intake rocker shaft 41 are disposed. , And the distance between the exhaust camshaft 39 and the exhaust rocker shaft 43 can be reduced as much as possible. Therefore, the intake passage 29 and the exhaust provided in the vicinity of the intake rocker shaft 41 and the exhaust rocker shaft 43 can be reduced. The degree of freedom of arrangement of the passage 30 is increased.

  Furthermore, according to the valve operating apparatus of the engine provided in the cylinder heads 22 and 22A of the engine 13 according to the present embodiment, the cam shaft support portion 71 on which the intake cam shaft 37 and the exhaust cam shaft 39 are supported is the cylinder. Since it is formed integrally with the head 22, the intake camshaft 37 and the exhaust camshaft 39 are arranged on the side far from the cam chain tunnel 69 and provided with one of the intake cam 38 and the exhaust cam 40. Sufficient support rigidity at the end can be secured.

  Furthermore, according to the valve operating apparatus of the engine provided in the cylinder heads 22 and 22A of the engine 13 according to this embodiment, the lower bearing housing 81 is provided separately from the cylinder heads 22 and 22A. It is not necessary to form a relief for drilling a head bolt (not shown) in the housing 81. As a result, it is possible to prevent lowering of rigidity of the lower bearing housing 81 that supports the intake cam driven sprocket 85 side of the intake cam shaft 37 around which the cam chain 87 is wound and the exhaust cam driven sprocket 86 side of the exhaust cam shaft 39. .

  Further, according to the valve operating apparatus of the engine provided in the cylinder heads 22 and 22A of the engine 13 according to the present embodiment, the cylinder head 22 includes the lower bearing housing 81 that is separate from the cylinder heads 22 and 22A. , 22A and the lower bearing housing 81 can be formed. Thereby, the oil which lubricated the sliding part in cylinder heads 22 and 22A can be smoothly led to cam chain tunnel 69, and the oil return performance from cylinder heads 22 and 22A to a crankcase can be improved.

The right view which showed an example of the motorcycle provided with the valve operating apparatus of the engine which concerns on this invention. Sectional drawing which showed the cylinder block provided with the valve operating apparatus of the engine which concerns on this invention. The top view which showed the cylinder block provided with the valve operating apparatus of the engine which concerns on this invention. The top view which showed the cylinder block provided with the valve operating apparatus of the engine which concerns on this invention. It is sectional drawing which follows the VV line | wire of FIG. 3, and sectional drawing which showed the cylinder block provided with the valve operating apparatus of the engine which concerns on this invention. It is sectional drawing which follows the VI-VI line of FIG. 3, and sectional drawing which showed the cylinder block provided with the valve operating apparatus of the engine which concerns on this invention. It is sectional drawing which follows the VII-VII line of FIG. 3, and is sectional drawing which decomposed | disassembled and showed the cylinder block provided with the valve operating apparatus of the engine which concerns on this invention. The top view which showed the other example of the cylinder block provided with the valve operating apparatus of the engine which concerns on this invention. The top view which showed the other example of the cylinder block provided with the valve operating apparatus of the engine which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motorcycle 2 Body frame 3 Bar handle 4 Front fork 5 Front fender 6 Front wheel 7 Disc brake 8 Rear fender 9 Swing arm 10 Rear wheel 11 Fuel tank 12 Seat 13 Engine 14 Radiator 21 Cylinder block 22, 22A Cylinder head 22a Side face part 22b Side face 23 Head cover 25 Combustion chamber 27 Intake port 28 Exhaust port 29 Intake passage 30 Exhaust passage 32 Valve seat 33 Valve seat 35 Intake valve 35a Umbrella portion 35b Stem 36 Exhaust valve 36a Umbrella portion 36b Stem 37 Intake camshaft 38 Intake cam 39 Exhaust camshaft 40 Exhaust cam 41 Intake rocker shaft 42 Intake rocker arm 43 Exhaust rocker shaft 44 Exhaust rocker arm 47 Stem guide 48 Spring -Nor 49 Spring seat 50 Valve spring 52 Stem guide 53 Spring retainer 54 Spring seat 55 Valve spring 57 Oil passage 58 Shim 59 Shim 61a Rocker shaft both ends shaft support portion 61b Rocker shaft both ends shaft support portion 62a Rocker shaft intermediate shaft support portion 62b Rocker shaft intermediate shaft Support part 64a Notch 64b Notch 65 Communication hole 67 Insertion hole 68 Retaining bolt 69 Cam chain tunnel 71 Cam shaft support part 72 Upper housing 73 Plug insertion hole 74a Bearing part 74b Bearing part 75, 75a, 75b Bolt hole 76 Fastening bolt 78 Oil Introducing groove 80 Upper bearing housing 81 Lower bearing housing 82a Bearing 82b Bearing 83 Head bolt seating surface 85 Intake cam driven sprocket 86 Exhaust cam driven sprocket DOO 87 cam chain 88 supply channel 90 through opening 91 closed bolt

Claims (1)

A cylinder head of a single cylinder engine,
Two intake valves and exhaust valves respectively provided in the cylinder head;
A camshaft for the intake valve and a camshaft for the exhaust valve, which are provided on the cylinder head and are rotatably supported;
A rocker shaft for the intake valve and a rocker shaft for the exhaust valve, which are provided on the cylinder head and disposed outside a region sandwiched between the two cam shafts;
Two rocker arms for the intake valve and two rocker arms for the exhaust valve, which are pivotally supported by the rocker shaft;
A cam for the intake valve and a cam for the exhaust valve that are provided on the cam shaft and swing the rocker arm;
The cylinder head includes end shaft support portions that respectively support both end portions of the rocker shaft, and an intermediate shaft support portion that supports an intermediate portion of the rocker shaft sandwiched between two rocker arms. A cam shaft support portion that is disposed in a portion between the two rocker arms and supports the cam shaft; the cam shaft support portion and the intermediate shaft support portion are connected to each other; Extended to the side of the arm,
The cylinder head includes a side wall portion for partitioning the cam chain tunnel at one axial end of the cam shaft, and a cam chain side cam that supports the cam shaft on the opposite side of the side wall portion across the cam chain tunnel. A shaft support,
The cam chain side cam shaft support portion is mainly constituted by a lower housing and an upper housing which are coupled to each other at a dividing surface passing through the shaft center of the cam shaft and formed separately from the cylinder head,
The lower housing, valve train features and to Rue engine further comprising an abutment surface which serves the contact with retaining features on one end surface of the rocker shaft is inserted from the insertion port formed in said side wall portion .

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