JP2006274894A - Lubrication structure for valve gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce an amount of oil flowing into tappet holes on both sides of the bearing part, which oil has been blown out of an radial oil port of a camshaft toward a bearing part and thereby to improve lubricity of the bearing part. <P>SOLUTION: In lubrication structure for a valve gear, a pair of valves is disposed each cylinder of an engine. A camshaft having cams corresponding to the pair of valves are journaled to a cylinder head through bearing parts formed in a cylinder head and a cam cap. A bearing part is disposed between a pair of valves, oil is supplied in an axial center oil passage extended from the oil supply source in an axial center direction of the camshaft, and the bearing part is lubricated by radial oil ports communicating with the axial center oil passage, extending in a radial direction of the camshaft, and opening to the bearing part. Each radial oil port of the camshaft is formed by avoiding a line in a direction of the maximum diameter of the cam passing a top part of the cam of each cylinder and the axial center of the camshaft. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lubrication structure for a valve operating device, and in particular, the amount of oil ejected from a diameter oil hole of a camshaft toward a bearing portion can be reduced to flow into tappet holes on both sides of the bearing portion. The present invention relates to a lubrication structure for a valve operating apparatus capable of improving the lubricity of a bearing portion by allowing oil to flow out into a wide portion of the valve.

  An engine mounted on a vehicle or the like is provided with a valve that opens and closes a port that communicates with a cylinder, and a valve operating device that supports a camshaft with a cam that is driven to open and close by directly hitting the valve. Some are provided. Some of these valve gears are shown in FIGS. In the figure, 202 is an engine, 204 is a cylinder block, 206 is a cylinder head, 208 is a cylinder, and 210 is a piston. The engine 202 has a plurality of cylinders 208, and a pair of valves 214 for opening and closing ports 212 communicating with the cylinders 208 are provided for each cylinder 208.

  The valve 214 is provided with a valve head 220 that contacts and separates from the valve seat 218 of the port 212 at one end of the valve stem 216, and holds the valve stem 216 on the cylinder head 206 so as to be movable in the axial direction by a valve guide 222. In the valve 214, a valve spring 224 is provided between the other end of the valve stem 216 and the cylinder head 206 so as to urge the port 212 in a closing direction. The tappet hole 228 is slidably held in the axial direction, and a shim 230 is attached to the top of the tappet 226.

  The valve gear 232 that opens and closes the pair of valves 214 has a plurality of support walls 234 arranged in parallel in the longitudinal direction on the upper surface of the cylinder head 206 and oriented in the width direction and positioned between the pair of valves 214. A cam cap 236 is attached to the support wall 234 with a mounting bolt 238, and the cam is oriented in the longitudinal direction of the cylinder head 206 between the head side bearing portion 240 of the support wall 234 and the cap side bearing portion 242 of the cam cap 236. The journal 246 of the shaft 244 is pivotally supported.

  A pair of cams 248 corresponding to the pair of valves 214 are formed on the camshaft 244 so as to be disposed on both sides in the axial center direction with the support wall 234 and the cam cap 2366 interposed therebetween. The pair of cams 248 are pressed by shims 230 mounted on the tops of the tappets 226 of the pair of valves 214, respectively. The camshaft 244 is connected to the crankshaft by a sprocket and a chain (not shown).

  The valve gear 232 rotates the camshaft 244 in synchronism with the crankshaft, causes the pair of cams 248 to slide in contact with the shim 230, pushes and retracts the pair of valves 214, and opens and closes the port 212. Thus, the engine 202 is a direct-stroke DOHC engine having a plurality of valves (intake valves or exhaust valves) 214 in each cylinder 208.

  In the lubrication structure of the valve gear 232, an axial oil passage 250 is formed in the axial direction of the camshaft 244. The camshaft 244 is provided with an oil introduction hole (not shown) for introducing oil into the shaft center oil passage 250 on one end side in the shaft center direction. The camshaft 244 is provided with a diameter oil hole 252 in the journal 246. The diameter oil hole 252 has one end communicating with the shaft center oil passage 250 and the other end extending in the radial direction of the camshaft 244 so as to open toward the head side bearing portion 240 and the cap side bearing portion 242. The journal 246 is formed.

  The lubrication structure of the valve gear 232 introduces oil to be pumped by an oil pump (not shown) as an oil supply source into an axial oil passage 250 from an oil introduction hole at one axial end side of the camshaft 244, The oil in the shaft center oil passage 250 flows toward the inner side of the passage away from the oil introduction side, and is ejected from a diameter oil hole 252 formed in the journal 246 of the camshaft 244 to be ejected from the head side bearing portion 240 and the cap side bearing. Lubricate the part 242.

The conventional lubrication structure for a valve operating device has an oil lubrication path for supplying lubricating oil in the oil passage in the camshaft to the bearing portion of the cylinder head from an oil discharge port provided in the radial direction of the journal. In a valve operating system in which a notch is formed on the edge in the width direction of the inner peripheral surface, the camshaft is axially centered so that the oil outlet is separated from the notch when the oil outlet passes near the notch. Some of them are displaced in the direction to prevent leakage of lubricating oil from the bearing portion.
JP-A-9-242523

In the conventional lubrication structure of a valve operating apparatus, lubricating oil is introduced into an oil passage in the cam shaft from one bearing portion that supports the cam shaft, and another bearing portion that supports the cam shaft through the oil passage. In the lubricating structure for supplying lubricating oil to the inner surface of the bearing portion on the lubricating oil introduction side, a half-circumferential groove is formed, and the cam shaft has a bearing portion furthest from the lubricating oil introduction side of the oil passage on the groove. There is an oil hole that communicates at the timing of receiving the valve lift reaction force, and lubricates the bearing portion with the lowest hydraulic pressure farthest from the lubricating oil introduction side at an optimal time.
JP-A-6-330719

In a conventional lubrication structure for a valve operating device, a lubrication structure in which lubricating oil in a first oil supply hole in a camshaft is supplied to a bearing portion from a plurality of second oil supply holes provided in a radial direction of a journal. Some journals are formed by displacing a plurality of second oil supply holes of the journal in the circumferential direction of the camshaft, and uniformly supplying lubricating oil to the inner peripheral surface of the bearing portion.
Japanese Patent Laid-Open No. 9-79019

In a conventional lubrication structure for a valve operating device, an oil supply hole is formed to communicate with an outer peripheral surface of the camshaft from an oil supply passage formed in the axial direction of the camshaft. In the lubrication structure that guides oil to the cam side by forming a gap between the bearing surface and the bearing surface, the gap is made larger at the part away from the oil introduction side, and the smallest gap is formed by the normal bearing clearance. Some gaps expose the oil supply hole from the bearing surface, increase the amount of oil supplied to the part away from the oil introduction side, and supply oil in a well-balanced manner.
JP-A-8-246832

  By the way, the valve operating device 232 provided in the engine 202 of the direct impact DOHC having a pair of valves 214 for each of the plurality of cylinders 208 shown in FIGS. 18 and 19 includes a head side bearing portion 240 and a cap side bearing. Cams 248 that drive the pair of valves 214 in substantially the same phase are provided on both sides in the axial direction of the journal 246 of the camshaft 244 that is pivotally supported by the portion 242.

  The lubrication structure of the valve gear 232 is provided with an axial oil passage 250 in the axial direction in the camshaft 244, and an axial oil is provided to a journal 246 that is pivotally supported by the head side bearing portion 240 and the cap side bearing portion 242. A diameter oil hole 252 penetrating the passage 250 is formed, oil is introduced from the oil introduction side on one end side of the shaft center oil passage 250 and guided to the back side in the passage on the other end side, and the oil in the shaft center oil passage 250 is Are ejected from the diameter oil hole 252 provided in the same phase in the circumferential direction of each journal 246 to the head side bearing portion 240 and the cap side bearing portion 242 for lubrication.

  However, the lubrication structure of the valve gear 232 includes a head-side bearing portion 240 and a cap that support the journal 246 on the inner side of the passage away from the oil introduction side where the oil on one end side of the shaft center oil passage 250 is introduced. The oil pressure supplied to the side bearing portion 242 is lower than the oil pressure supplied to the other head side bearing portion 240 and the cap side bearing portion 242 on the oil introduction side. In order to secure the amount, it is necessary to set a large discharge amount of an oil pump (not shown) driven by the engine 202, which causes a problem of increasing friction.

  Further, as shown in FIG. 20, the lubricating structure of the valve gear 232 is such that the circumferential position of the radial oil hole 252 provided in the journal 246 of the camshaft 244 is in the cam maximum radial direction of the cam 248 on both sides of the journal 246. When the cam phase is near the maximum lift, the journal 246 is pushed by the reaction force of the valve spring 224 toward the cap side bearing portion 242 in the direction opposite to the maximum diameter of the cam 248, so Since there is a clearance (sliding gap) S between the diameter direction, that is, between the head side bearing portion 240 and the journal 246, the oil in the axial oil passage 250 passes through the diameter oil hole 252 and enters the head side bearing portion 240. A large amount will be ejected.

  However, the position of the diameter oil hole 252 at this time is notched by the tappet holes 228 on both sides in the width direction of the head side bearing portion 240 provided in the cylinder head 206, as shown in FIG. Since it faces the head-side bearing portion 240 that is narrow, most of the oil ejected to the head-side bearing portion 240 escapes to the tappet hole 228 side, which causes a disadvantage of lowering the hydraulic pressure. .

  Further, as shown in FIG. 21, the lubrication structure of this valve operating device 232 is such that when the diameter oil hole 252 is 180 degrees opposite to the cam maximum diameter direction of the cam 248, the journal 246 is camped by the reaction force of the valve spring 224. 246 is pressed against the cap-side bearing portion 242 in the direction opposite to the maximum diameter of the H.246, the oil held in the cap-side bearing portion 242 flows back through the diameter oil hole 252 and escapes to the axial oil passage 250, and lubrication is performed. Is inconvenient.

  According to the present invention, a pair of valves are provided in each cylinder of an engine, and a camshaft formed with a cam corresponding to the pair of valves is pivotally supported on the cylinder head via a bearing portion formed in the cylinder head and the cam cap. The bearing is disposed between the pair of valves, oil is supplied from an oil supply source to an axial oil passage provided in the axial direction of the camshaft, and communicated with the axial oil passage and In a lubrication structure of a valve operating device that lubricates the bearing portion by a radial oil hole extending in a radial direction of the cam shaft and opening to the bearing portion, each diameter oil hole of the cam shaft is connected to a top portion of the cam of each cylinder and the cam shaft. It is characterized in that it is formed so as to avoid the cam maximum radial direction line passing through the shaft center.

  According to the lubricating structure of the valve operating device of the present invention, each diameter oil hole of the camshaft is formed so as to avoid the cam maximum radial direction line passing through the top of the cam of each cylinder and the axis of the camshaft. In the range where a load is applied to the bearing portion arranged between the pair of valves due to the reaction force, each diameter oil hole of the camshaft is not positioned on the maximum radial direction line, so it is ejected from the diameter oil hole toward the bearing portion. Thus, the amount of the oil flowing out to the tappet guide holes on both sides of the bearing portion can be reduced, and the oil can be allowed to flow out to the widest portion of the bearing portion as much as possible to improve the lubricity of the bearing portion.

According to the lubricating structure of the valve operating apparatus of the present invention, each diameter oil hole of the camshaft is formed so as to avoid the cam maximum radial direction line passing through the top of the cam of each cylinder and the axis of the camshaft. The amount of oil jetted from the bearing toward the bearing is reduced to the tappet guide holes on both sides of the bearing, and the oil flows out to the widest part of the bearing as much as possible to improve the lubricity of the bearing. .
Embodiments of the present invention will be described below with reference to the drawings.

  1 to 15 show an embodiment of the present invention. 8 and 9, 2 is an engine mounted on a vehicle (not shown), 4 is a cylinder block, 6 is an oil pan, 8 is a cylinder head, 10 is a head cover, and 12 is a chain cover. The engine 2 supports a crankshaft 14 below the cylinder block 4 and an oil pan 6 is attached to the lower end of the cylinder block 4 so as to cover the crankshaft 14.

  In the engine 2, a cylinder head 8 is attached to the upper part of the cylinder block 4, a head cover 10 is attached to the cylinder head 8, and a chain cover 12 is attached to one end side in the longitudinal direction of the cylinder block 4 and the cylinder head 8.

  As shown in FIGS. 10 to 12, the engine 2 has a plurality of cylinders arranged in series in the cylinder block 4, in this embodiment, four cylinders 16 (# 1 cylinder to # 4 cylinder), and each of the pistons 18 is provided with a piston 18. Built-in slidable. The piston 18 is connected to the crankshaft 14 via a connecting rod (not shown). The engine 2 is provided with a pair of intake ports 20 and exhaust ports 22 communicating with the respective cylinders 16 on each side in the width direction of the cylinder head 8, and includes an intake valve 24 and an exhaust valve 26 that open and close the intake port 20 and the exhaust port 22. One pair is provided for each cylinder 16.

  The intake valve 24 is provided with an intake valve head 32 that is brought into contact with and separated from the intake valve seat 30 of the intake port 20 at one end of the intake valve stem 28, and the intake valve stem 28 can be moved in the axial direction by the intake valve guide 34 to the cylinder head 8. keeping. The intake valve 24 has an intake valve spring 36 urged in a direction to close the intake port 20 between the other end side of the intake valve stem 28 and the cylinder head 8, and an intake tappet externally mounted on the other end of the intake stem 28. 38 is slidably held in the intake tappet hole 40 of the cylinder head 8 in the axial direction, and an intake shim 42 is in contact with the top of the intake tappet 38.

  The exhaust valve 26 is provided with an exhaust valve head 48 that is brought into contact with and separated from the exhaust valve seat 46 of the exhaust port 22 at one end of the exhaust valve stem 44, and the exhaust valve stem 44 can be moved in the axial direction by the exhaust valve guide 50 to the cylinder head 8. keeping. The exhaust valve 26 has an exhaust valve spring 52 that urges the exhaust port 22 in a direction to close the exhaust port 22 between the other end side of the exhaust valve stem 44 and the cylinder head 8, and is exhausted on the other end of the exhaust valve stem 44. The tappet 54 is slidably held in the exhaust tappet hole 56 of the cylinder head 8 in the axial direction, and an exhaust shim 58 is in contact with the top of the exhaust tappet 56.

  The intake valve 24 and the exhaust valve 26 are opened and closed by a valve gear 60. The valve gear 60 is provided with a plurality of support walls 62 oriented in the width direction on the upper surface of the cylinder head 8 in parallel in the longitudinal direction. The support wall 62 is disposed between each pair of the intake valve 24 and the exhaust valve 26 for each cylinder 16, and is disposed on one end side in the longitudinal direction of the cylinder head 8. A semi-cylindrical head-side intake bearing portion 64 is formed on one side in the width direction of the cylinder head 8 on the support wall 62, and a semi-cylindrical head-side exhaust bearing portion 66 is formed on the other side in the width direction. .

  As shown in FIGS. 13 to 15, the head side intake bearing portion 64 disposed between the pair of intake valves 24 of the cylinder 18 is notched by intake tappet holes 40 at both sides in the longitudinal direction of the cylinder head 8. Thus, an intake notch 68 is formed and narrowed. Further, the head side exhaust bearing portion 66 disposed between the pair of exhaust valves 26 of the cylinder 16 is notched by the exhaust tappet holes 56 on both sides in the width direction in the longitudinal direction of the cylinder head 8 to form an exhaust notch portion 70. And narrowed.

  On the upper surface of the support wall 62, an intake cam cap 72 is attached to one side in the width direction of the cylinder head 8 by an intake cap attachment bolt 74, and an exhaust cam cap 76 is attached to the other side in the width direction by an exhaust cap attachment bolt 78. . The intake cam cap 72 has a semi-cylindrical cap-side intake bearing portion 80 corresponding to the head-side intake bearing portion 64. A semi-cylindrical cap side exhaust bearing portion 82 corresponding to the head side exhaust bearing portion 66 is formed in the exhaust cam cap 76. The intake cam cap 72 and the exhaust cam cap 76 attached to the support wall 62 on one end side in the longitudinal direction of the cylinder head 8 are integrally connected by a connecting portion 84 as shown in FIGS.

  Between the head-side intake bearing portion 64 of the support wall 62 and the cap-side intake bearing portion 80 of the intake cam cap 72, each intake journal 88 of the intake cam shaft 86 oriented in the longitudinal direction of the cylinder head 8 is pivotally supported. is doing. The intake camshaft 86 is formed with a pair of intake cams 90 corresponding to the pair of intake valves 24 so as to be disposed on both sides in the axial direction with the support wall 62 and the intake cam cap 72 interposed therebetween. The pair of intake cams 90 are pressed by intake shims 42 mounted on the tops of the intake tappets 38 of the pair of intake valves 24, respectively.

  Each exhaust journal 94 of the exhaust cam shaft 92 oriented in the longitudinal direction of the cylinder head 8 is pivotally supported between the head side exhaust bearing portion 66 of the support wall 62 and the cap side exhaust bearing portion 82 of the exhaust cam cap 76. is doing. The exhaust camshaft 92 is formed with a pair of exhaust cams 96 corresponding to the pair of exhaust valves 26 so as to be disposed on both sides in the axial direction with the support wall 62 and the exhaust cam cap 76 interposed therebetween. The pair of exhaust cams 96 are pressed by exhaust shims 58 mounted on the tops of the exhaust tappets 56 of the pair of exhaust valves 26, respectively.

  An intake cam sprocket 98 is attached to the intake camshaft 86 at one end in the longitudinal direction. An exhaust cam sprocket 100 is attached to the exhaust cam shaft 92 at one end in the longitudinal direction. A timing chain 102 is wound around the intake / exhaust cam sprockets 98 and 100. The timing chain 102 is hooked on a crank sprocket 104 attached to one end side in the longitudinal direction of the crankshaft 14.

  The valve gear 60 rotates the intake camshaft 86 and the exhaust camshaft 92 in synchronization with the crankshaft 14 by the timing chain 102, and the pair of intake cams 90 and exhaust cams 96 are in sliding contact with the intake shim 42 and the exhaust shim 58. Thus, the pair of intake valve 24 and exhaust valve 26 are pushed and retracted to open and close intake port 20 and exhaust port 22. Thus, the engine 2 is a direct-stroke DOHC engine having a plurality of intake valves 24 and exhaust valves 26 in each cylinder 18.

  As shown in FIGS. 8 and 9, the lubricating structure of the valve gear 60 is provided with an oil pump 106 as an oil supply source on one end side in the longitudinal direction of the crankshaft 14. The oil pump 106 is rotatably accommodated in a pump housing 108 provided on the chain cover 12, a pump plate 110 attached to the pump housing 108, and a rotor chamber 112 formed by the pump housing 108 and the pump plate 110. An inner rotor 114 and an outer rotor 116.

  The oil pump 106 includes a suction port 120 and a discharge port 122 that communicate with a pump chamber 118 formed between the inner rotor 114 and the outer rotor 116. An oil strainer 126 located at the bottom of the oil pan 6 is communicated with the suction port 120 via a suction pipe 124. The discharge port 122 communicates with the oil filter 130 via a relief valve (not shown) through the discharge passage 128. The oil filter 130 is communicated with a head-side oil passage 134 formed at one end in the longitudinal direction of the cylinder head 8 by a block-side oil passage 132 formed at one end in the longitudinal direction of the cylinder block 4.

  The head-side oil passage 134 communicates with a connecting portion oil passage 136 formed in a connecting portion 84 of the intake cam cap 72 and the exhaust cam cap 76 that is attached to the support wall 62 on one end side in the longitudinal direction of the cylinder head 8. The connecting portion oil passage 136 includes a cap intake side oil passage 138 formed in the cap side intake bearing portion 80 of the intake cam cap 72 and a cap exhaust side oil passage formed in the cap side exhaust bearing portion 82 of the exhaust cam cap 76. 140.

  An intake journal 88 on one end side in the axial direction of an intake camshaft 86 that is pivotally supported by a support wall 62 on one end side in the longitudinal direction of the cylinder head 8 and an intake cam cap 72 attached to the support wall 62 has an outer periphery. A plurality of intake side oil introduction holes 142 are formed toward the center. The intake side oil introduction hole 142 communicates with one end side to the cap intake side oil passage 138 and the other end side to an intake side axial oil passage 144 provided in the axial direction of the intake camshaft 86. The intake-side axial oil passage 144 is formed to extend to the vicinity of the other end side in the axial direction.

  One intake side diameter oil hole 146 is formed from the center toward the outer periphery in the other intake journals 88 except for the intake journal 88 on one end side in the axial center direction of the intake camshaft 86. The intake-side oil hole 146 has one end communicating with the intake-side axial oil passage 144 and the other end extending in the radial direction and opening toward the head-side intake bearing portion 64 and the cap-side intake bearing portion 80. The intake journal 88 is formed as described above.

  An exhaust journal 94 on one end in the axial direction of an exhaust camshaft 92 that is pivotally supported by a support wall 62 on one end side in the longitudinal direction of the cylinder head 8 and an exhaust cam cap 76 attached to the support wall 62 includes: A plurality of exhaust-side oil introduction holes 148 are formed from the outer periphery toward the center. The exhaust side oil introduction hole 148 has one end communicating with the cap exhaust side oil passage 140 and the other end communicating with an exhaust side axial oil passage 150 provided in the axial direction of the exhaust camshaft 92. The exhaust-side axial oil passage 150 is formed to extend to the vicinity of the other end side in the axial direction.

  One exhaust side diameter oil hole 152 is formed in the other exhaust journal 94 excluding the exhaust journal 94 on one end side in the axial center direction of the exhaust camshaft 92 from the center toward the outer periphery. The exhaust side diameter oil hole 152 communicates at one end side with the exhaust side axial oil passage 150 and extends at the other end side in the radial direction so as to open toward the head side exhaust bearing portion 66 and the cap side exhaust bearing portion 82. Thus, the exhaust journal 94 is formed.

  The lubrication structure of the valve operating device 60 is configured so that oil to be pumped by an oil pump 106 serving as an oil supply source passes through a block side oil passage 132, a head side oil passage 140, and a connecting portion oil passage 136 in the longitudinal direction of the cylinder head 8. Supplied to the cap intake side oil passage 138 of the integral intake cam cap 72 and the cap exhaust side oil passage 140 of the exhaust cam cap 76 attached to the support wall 62 on one end side, and the intake air on one end side in the axial direction of the intake cam shaft 86. The exhaust oil is introduced into the intake-side axial oil passage 144 from the side oil introduction hole 142 and is introduced into the exhaust-side axial oil passage 150 from the exhaust-side oil introduction hole 148 on one end side in the axial direction of the exhaust camshaft 92.

  The oil in the intake-side axial oil passage 144 flows toward the inner side of the passage away from the oil introduction side, and is ejected from the intake-side diameter oil hole 146 formed in the intake journal 88 of the intake camshaft 86 to the head side. The intake bearing portion 64 and the cap side intake bearing portion 80 are lubricated. Further, the oil in the exhaust side shaft oil passage 150 flows toward the inner side of the passage away from the oil introduction side, and is ejected from the exhaust side diameter oil hole 152 formed in the exhaust journal 94 of the exhaust camshaft 92. The head side exhaust bearing portion 66 and the cap side exhaust bearing portion 82 are lubricated.

  The lubrication structure of the valve operating device 60 is to improve the lubricity of the bearing portion by reducing the amount of oil jetted from the diameter oil hole of the camshaft toward the bearing portion to the tappet holes on both sides of the bearing portion. is there. The valve gear 60 includes an intake camshaft 86 and an exhaust camshaft 92 that are configured in the same manner. Therefore, the intake camshaft 86 will be described below as an example.

  As shown in FIG. 1, the lubrication structure of the valve gear 60 includes the intake side oil holes 146 of the intake camshaft 86, the top 154 of the intake cam 90 of each cylinder 16, and the axis C of the intake camshaft 86. It is formed so as to avoid the cam maximum radial direction line L1 passing through.

  As a result, the lubricating structure of the valve operating device 60 has a cap side intake bearing portion 80 disposed between the pair of intake valves 90 in response to the reaction force of the intake valve spring 36 as shown in FIGS. In the range where the load is applied, the intake-side diameter oil holes 146 of the intake camshaft 86 are not positioned on the cam maximum radial direction line L1 in all the cylinders 16.

  For this reason, the lubrication structure of the valve operating device 60 is configured to reduce the amount of oil ejected from the intake-side diameter oil hole 146 toward the head-side intake bearing portion 64 to the intake tappet holes 40 on both sides of the head-side intake bearing portion 64. The oil can be allowed to flow out to the widest portion of the head side intake bearing portion 64 as much as possible, and the lubricity of the head side intake bearing portion 64 and the cap side intake bearing portion 80 can be improved.

  As shown in FIG. 1, the lubricating structure of the valve gear 60 is formed so that the intake-side diameter oil hole 146 avoids an extension line L2 extending away from the top 154 of the intake cam 90 of the cam maximum radial direction line L1. Provided.

  As a result, the lubricating structure of the valve operating device 60 has a cap side intake bearing portion 80 disposed between the pair of intake valves 90 in response to the reaction force of the intake valve spring 36 as shown in FIGS. In the range where the load is applied to each of the cylinders 16, the intake-side diameter oil holes 146 of the intake camshaft 86 are positioned on the extended line L2 of the cam maximum radial direction line L1 extending away from the top portion 154 of the intake cam 90. Not.

  For this reason, the lubrication structure of the valve gear 60 is such that the oil held in the clearance S between the cap side intake bearing portion 80 and the intake journal 88 of the intake camshaft 86 flows back through the intake side diameter oil hole 146. The amount of flow into the intake-side axial oil passage 144 can be reduced, and the lubricity of the head-side intake bearing portion 64 and the cap-side intake bearing portion 80 can be improved.

  As shown in FIGS. 1 and 6, the lubricating structure of the valve gear 60 is such that the intake-side diameter oil holes 146 of the intake camshaft 86 are aligned in the circumferential direction.

  As a result, the lubricating structure of the valve gear 60 can be processed without rotating the intake camshaft 86 when each intake-side oil hole 146 of the intake camshaft 86 is processed, or each intake-side oil hole 146. All of these can be processed at the same time, the processing becomes easy, the processing equipment can be simplified and the descent time can be shortened.

  As shown in FIGS. 2 and 3, the lubrication structure of the valve gear 60 includes a journal 88 (# 1 cylinder / # 2 cylinder) provided on the intake camshaft 86 on the oil introduction side of the intake-side axial oil passage 144. The intake-side diameter oil hole 146 that lubricates the head-side intake bearing portion 64 and the cap-side intake bearing portion 80 that are pivotally supported is an extension line L2 extending away from the top portion 154 of the intake cam 86 of the cam maximum radial direction line L1. And a vertical direction line L3 that passes through the axis C of the intake camshaft 86 and perpendicularly intersects the cam maximum radial direction line L1.

  As a result, the lubricating structure of the valve train 60 is such that the oil introduction side of the intake side axial oil passage 144 has a high hydraulic pressure, so that the intake side diameter oil hole 146 on the oil introduction side is connected to the cylinder 16 ( (# 1 cylinder, # 2 cylinder) can prevent a large amount of oil from flowing into the intake tappet hole 40, and the cylinder 16 is located on the inner side of the passage that is separated from the oil introduction side of the intake-side axial oil passage 144. The amount of oil necessary for lubricating the head side intake bearing portion 64 and the cap side intake bearing portion 80 of (# 3 cylinder / # 4 cylinder) can be ensured.

  As shown in FIG. 1, the lubricating structure of the valve gear 60 is such that a head-side intake bearing portion 64 disposed on one end side in the axial direction of the intake camshaft 86 by a head-side oil passage 134 formed in the cylinder head 8. In addition, oil is supplied to the cap-side intake bearing portion 80, and an intake-side axial oil passage provided in the axial direction of the intake camshaft 86 via the head-side intake bearing portion 64 and the cap-side intake bearing portion 80 on one end side. As shown in FIG. 5, the head-side intake bearing 64 and the cap-side intake that are farthest from the head-side intake bearing 64 and the cap-side intake bearing 80 on the one end side in the axial direction are provided. The intake-side diameter oil hole 146 formed in the bearing portion 80 passes through the cam maximum radial direction line L1 and the axis C of the intake camshaft 86 and perpendicularly intersects the cam maximum radial direction line L1. It is formed between the Mukosen L3.

  As a result, the lubricating structure of the valve gear 60 is configured such that the intake side oil hole 146 is formed between the cam maximum radial direction line L1 and the vertical direction line L3, so that oil is introduced into the intake side axial oil passage 144. It is possible to increase the amount of oil flowing out to the head side intake bearing portion 64 and the cap side intake bearing portion 80 of the cylinder 16 (# 4 cylinder) on the farthest side in the passage farthest from the side. The oil pressure is lower than the oil introduction side as the oil is supplied to the intake-side axial oil passage 144 from the oil introduction side. The lubricity of the head side intake bearing portion 64 and the cap side intake bearing portion 80 of a certain cylinder 16 (# 4 cylinder) can be improved.

  Further, the lubrication structure of the valve gear 60 is such that the head-side intake bearing portion 64 and the cap side on the innermost side in the passage farthest from the oil introduction side provided with the intake-side oil introduction hole 142 of the intake-side axial oil passage 144. The farthest cylinder (# 4 cylinder) 16 corresponding to the intake bearing 80 and the other cylinders (# 1 to # 3 cylinder) 16 whose ignition timings are before and after the farthest cylinder (# 4 cylinder) 16 The cylinders close to the most distant cylinder (# 4 cylinder) 16 are compared with each other as the next cylinder 16, and the radial direction is between the cam maximum radial direction lines L1 between the most distant cylinder (# 4 cylinder) 16 and the next cylinder 16. The intake side diameter oil hole 146 is extended to the bottom.

  As a result, the lubrication structure of the valve gear 60 is located on the deepest side in the passage that is farthest away from the oil introduction side of the intake-side axial oil passage 144, so that the oil pressure in the intake-side diameter oil hole 146 is the lowest separation. -Side head-side intake bearing portion 64 and cap-side intake bearing portion 80, and the most separated head-side intake bearing portion 64 and cap-side intake bearing portion 80 near the oil introduction side head-side intake bearing portion 64 and cap-side The amount of lubrication with the intake bearing 80 can be increased, and the lubricity of the head-side intake bearing 64 and the cap-side intake bearing 80 can be improved.

  In the lubrication structure of the valve gear 60, the next cylinder 16 is disposed adjacent to the farthest cylinder (# 4 cylinder) 16.

  As a result, the lubrication structure of the valve gear 60 is located on the deepest side in the passage that is farthest away from the oil introduction side of the intake-side axial oil passage 144, so that the oil pressure in the intake-side diameter oil hole 146 is the lowest separation. Head-side intake bearing portion 64 and cap-side intake bearing portion 80 of the farthest-separated cylinder (# 4 cylinder) 16 on the side, and the most distantly-side head-side intake bearing portion 64 and cap-side intake bearing where the hydraulic pressure decreases next. The amount of oil supplied to the head side intake bearing portion 64 and the cap side intake bearing portion 80 of the next cylinder (# 3 cylinder) 16 adjacent to the oil introduction side of the portion 80 can be increased. The lubricity of the bearing part 64 and the cap side intake bearing part 80 can be improved.

  As shown in FIG. 7, the lubrication structure of the valve train 60 is extended by shifting the intake side diameter oil hole 146 in the circumferential direction toward the cam maximum radial direction line L1 side of the farthest cylinder (# 4 cylinder) 16. I am letting.

  As a result, the lubricating structure of the valve operating device 60 allows the amount of oil flowing out to the head-side intake bearing portion 64 and the cap-side intake bearing portion 80 to be the most separated from the next cylinder (# 3 cylinder) 16 side. It can be increased on the cylinder (# 4 cylinder) 16 side, and the amount of lubrication can be made as uniform as possible.

  In the above embodiment, the intake camshaft 86 has been described as an example, but the exhaust side diameter oil hole 152 formed in the exhaust journal 94 of the exhaust camshaft 92 is configured similarly to the intake side diameter oil hole 146. By doing so, the same effect can be achieved.

  FIG. 16 shows a first modification. The lubrication structure of the valve gear 60 is such that the diameters D1 to D4 of the intake-side diameter oil hole 146 communicating with the intake-side axial oil passage 144 are separated from the oil introduction side rather than the oil introduction side. It is formed so as to increase as it approaches (D1 <D2 <D3 <D4).

  The lubrication structure of the valve gear 60 is formed so that the diameters D1 to D4 of the intake-side diameter oil holes 146 increase with distance from the oil introduction side and closer to the inner side of the passage. The required oil supply amount can be ensured even at the back side in the passage where the pressure becomes low, and the oil is evenly distributed to all the head side intake bearing portions 64 and the cap side intake bearing portions 80 from the oil introduction side to the back side in the passage. Can be supplied, and lubricity can be improved.

  FIG. 17 shows a second modification. The lubrication structure of the valve gear 60 is formed on the intake journal 88 and has one end on the other end of the intake-side oil hole 146 communicating with the intake-side axial oil passage 144 and on the front side in the rotational direction of the intake camshaft 86. An expanded portion 156 is formed so as to expand toward the front.

  In the lubrication structure of the valve gear 60, an expansion portion 156 is formed on the other end side of the intake-side diameter oil hole 146 formed in the intake journal 88 so as to expand toward the front side in the rotation direction of the intake camshaft 86. Accordingly, oil can be positively supplied to the oil in the forward direction of the rotating intake journal 88, and an oil film can be formed between the head-side intake bearing portion 64 and the cap-side intake bearing portion 80, thereby improving lubricity. Can be improved.

  According to the lubricating structure of the valve operating apparatus of the present invention, each diameter oil hole of the camshaft is formed so as to avoid the cam maximum radial direction line passing through the top of the cam of each cylinder and the axis of the camshaft. The amount of oil jetted from the bearing toward the bearing is reduced to the tappet guide holes on both sides of the bearing, and the oil flows out to the widest part of the bearing as much as possible to improve the lubricity of the bearing. It can be applied to a 4-cycle engine.

1 shows an embodiment of a lubricating structure of a valve operating device, (A) is a side view of an intake camshaft, (B) is a sectional view taken along line BB of (A), and (C) is CC of (A). (D) is a sectional view taken along line DD in (A), (E) is a sectional view taken along line EE in (A), and (F) is taken along line FF in (A). Sectional drawing and (G) are sectional drawings by the GG line of (A). It is sectional drawing of the intake journal site | part in the oil introduction side most. It is sectional drawing of the intake journal site | part which is 2nd toward the inner side in a channel | path from an oil introduction side. It is sectional drawing of the intake journal site | part which is 3rd toward the inner side in a channel | path from an oil introduction side. It is sectional drawing of the intake journal site | part which is the innermost back | inner side of a channel | path from an oil introduction side. It is sectional drawing of the intake journal site | part which shows the relationship between all the intake cams and an intake side diameter oil hole. It is sectional drawing of the intake journal site | part of a furthest cylinder. It is a partially broken front view of an engine. It is a partially broken side view of an engine. It is a partially broken top view of a cylinder head. It is a partially broken side view of a cylinder head. It is sectional drawing of a cylinder head. It is a top view of a cylinder head. It is sectional drawing by the XIV-XIV line | wire of FIG. It is sectional drawing by the XV-XV line | wire of FIG. A side view of an intake camshaft showing a first modification, It is sectional drawing of the intake journal site | part which shows a 2nd modification. It is sectional drawing of the cylinder head site | part of the engine which shows a prior art example. It is sectional drawing by the XIX-XIX line | wire of FIG. It is sectional drawing of the journal site | part formed by directing a diameter oil hole to the cam largest radial direction line. It is sectional drawing of the journal site | part formed by directing a diameter oil hole to the reverse direction from the cam largest radial direction line | wire.

Explanation of symbols

2 Engine 4 Cylinder block 8 Cylinder head 14 Crankshaft 16 Cylinder 24 Intake valve 26 Exhaust valve 40 Intake tappet hole 56 Exhaust tappet hole 60 Valve operating device 62 Support wall 64 Head side intake bearing portion 66 Head side exhaust bearing portion 72 Intake cam cap 76 Exhaust cam cap 80 Cap side intake bearing portion 82 Cap side exhaust bearing portion 86 Intake cam shaft 88 Intake journal 90 Intake cam 92 Exhaust cam shuff 94 Exhaust journal 96 Exhaust cam 106 Oil pump 132 Block side oil passage 134 Head side oil passage 136 Connection Part oil passage 138 Cap intake side oil passage 140 Cap exhaust side oil passage 142 Intake side oil introduction hole 144 Intake side axial oil passage 146 Intake side diameter oil hole 148 Exhaust Side oil introduction hole 152 exhaust side axial oil passage

Claims (8)

  A pair of valves are provided in each cylinder of the engine, and a camshaft formed with a cam corresponding to the pair of valves is pivotally supported on the cylinder head via a bearing portion formed on the cylinder head and the cam cap. The bearing is disposed between the valves, oil is supplied from an oil supply source to an axial oil passage provided in the axial direction of the camshaft, communicated with the axial oil passage, and has a diameter of the camshaft. In a lubricating structure of a valve operating apparatus that lubricates the bearing portion with a diameter oil hole that extends in a direction and opens to the bearing portion, each diameter oil hole of the camshaft is connected to the top of the cam of each cylinder and the axis of the camshaft. A lubrication structure for a valve operating device, characterized in that it is formed so as to avoid a cam maximum radial direction line passing through the valve.   2. The lubrication structure for a valve operating apparatus according to claim 1, wherein the diameter oil hole is formed so as to avoid an extension line extending away from the top of the cam in the cam maximum radial direction line.   The lubricating structure for a valve operating device according to claim 1 or 2, wherein oil holes of each diameter of the camshaft are aligned in the circumferential direction.   The position of the most distant cylinder corresponding to the bearing portion that is furthest away from the oil introduction side of the shaft center oil passage is compared with the cylinder that has an ignition timing before and after the most distant cylinder. 2. The valve operating device according to claim 1, wherein the oil hole is extended in a circumferential direction between each cam maximum radial direction line of the most separated cylinder and the next cylinder. Lubrication structure.   The lubrication structure for a valve operating apparatus according to claim 4, wherein the next cylinder is disposed adjacent to the farthest cylinder.   6. The lubricating structure for a valve operating device according to claim 4, wherein the diameter oil hole is shifted and extended in the circumferential direction toward the cam maximum radial direction line side of the farthest separated cylinder. .   The diameter oil hole for lubricating a bearing portion that supports a camshaft on the oil introduction side of the shaft center oil passage includes an extension line to a side away from the top of the cam in the cam maximum radial direction line, and the camshaft The lubrication structure for a valve operating apparatus according to claim 2, wherein the lubricating structure is formed between a vertical direction line perpendicular to the maximum cam diameter direction line and an axial center of the cam.   Oil is supplied to the bearing portion disposed on one end side in the axial direction of the camshaft through a head-side oil supply passage formed in the cylinder head, and the camshaft shaft center is provided via the bearing portion on the one end side. Oil is supplied to the axial oil passage provided in the direction, and the diameter oil hole formed in the bearing portion that is furthest away from the bearing portion on the one end side to the other end side in the axial direction is defined as the maximum cam radial line. 3. The lubricating structure for a valve operating apparatus according to claim 2, wherein the lubricating structure is formed between a vertical direction line that intersects with a cam maximum radial direction line through a shaft center of the cam shaft.

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