JP2009097398A - Oil circulating structure for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide oil circulating structure for a vehicular engine capable of efficiently circulating oil even in turning travelling and capable of improving lubricating performance by preventing deterioration of oil return. <P>SOLUTION: This oil circulating structure comprises a chain chamber 11 housing a timing chain 23 to be wound around an inlet cam sprocket 19 and an exhaust cam sprocket 21, which are arranged in an inlet camshaft 15 and an exhaust camshaft 17 arranged in a valve chamber 7a provided in a cylinder head 7, and an idler sprocket 14 to be driven for rotation by a crankshaft 12, and an oil reservoir 5 provided in the bottom of a cylinder block. A first oil flow straightening means 35 is provided to communicate the chain chamber 11 with the oil reservoir 5, to communicate the chain chamber 11 with the valve chamber 7a and to adjust the oil flow along a rising region of the timing chain 23 by cutting the flow of the oil flowing to the exhaust cam sprocket 21. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an oil circulation structure of an engine, and more particularly to an engine oil circulation structure in which a part of oil supplied to a valve operating chamber returns to an oil reservoir chamber through a chain chamber.

  Conventionally, as an oil lubricant structure of this type of engine, there is a structure as disclosed in, for example, Patent Document 1 and Patent Document 2.

  That is, an engine that uses a timing chain uses a chain chamber that houses the timing chain as an oil return passage that communicates the valve chamber and the oil reservoir chamber, so that the oil is passed from the valve chamber side by the circulating timing chain. The oil can be efficiently returned to the reservoir, and the oil circulation efficiency is improved. The oil rated capacity can be reduced by improving the oil circulation efficiency. Further, by using the chain chamber as an oil return passage, necessary lubrication portions of the chain chamber such as the timing chain, the cam sprockets, and the chain tensioner are simultaneously lubricated, so that the structure can be simplified.

  Further, as disclosed in Patent Document 3, in a horizontally opposed engine, a V-type engine, and the like having a plurality of banks, an oil reservoir chamber provided in a valve operating chamber of each bank and a bottom of a cylinder block is provided via a chain chamber. An oil circulation device that communicates is known. In this case, the oil stored in the oil reservoir is supplied to each valve chamber by an oil pump via an oil gallery and the like to lubricate the valve chamber. The oil lubricated in the valve chamber is supplied to the oil return passage and the chain chamber. Is returned to the oil reservoir.

JP 2004-251199 A JP 2006-70758 A JP 2001-115813 A

  However, in the horizontally opposed engine and the V-type engine, the height difference between the oil reservoir and the valve chamber is relatively small, and when a vehicle equipped with this type of engine turns, The lateral acceleration (lateral G) causes the oil to flow from the oil reservoir chamber side to the valve chamber side of the bank on one side, to be unevenly distributed and stay. For this reason, since it becomes difficult to return to the oil reservoir, there is a concern that the oil in the oil reservoir is relatively reduced and air is sucked into the oil pump, or that the lubrication efficiency is lowered due to the deterioration of the oil return.

  As a countermeasure, if the rated capacity of oil is increased, an increase in the capacity of the oil reservoir chamber causes an increase in size and weight of the engine.

  Accordingly, an object of the present invention made in view of such points is to efficiently circulate oil even in a situation where acceleration or the like acts on the engine without increasing the rated capacity of the oil, and to prevent deterioration of oil return. An object of the present invention is to provide an engine oil circulation device capable of improving lubricity.

  The engine oil circulation structure according to claim 1, which achieves the above object, includes a first cam sprocket and a first cam sprocket respectively disposed on a first camshaft and a second camshaft disposed in a valve operating chamber provided in a cylinder head. 2 cam sprockets, chain sprockets that are driven to rotate by a crankshaft, an outward movement region from the chain sprockets to the second cam sprockets wound around the sprockets, and the second cam sprockets to the first cam sprockets. The upper moving area, the timing chain that circulates from the second cam sprocket to the chain sprocket, and the upper side of the inward movement range of the timing chain between the chain sprocket and the first cam sprocket. A chain that houses the extended chain guide In an engine having a chamber and an oil reservoir chamber provided at the bottom of the cylinder block, the chain chamber and the oil reservoir chamber are communicated with each other via an oil return passage, and the chain chamber and the valve chamber are communicated with oil. A first oil rectifier is provided in the chain chamber for communicating with the second cam sprocket and for rectifying the oil flow along the rising movement region of the timing chain. It is characterized by that.

  According to the present invention, when acceleration is applied to the engine and oil flows into the valve chamber from the oil reservoir chamber side, excess oil that has flowed into the valve chamber flows out from the oil communication passage into the chain chamber. On the other hand, the oil staying in the lower part on the cylinder head side in the chain chamber is blocked by the first oil rectifying means from the oil flow that rotates around the second cam sprocket. Accordingly, the oil is rectified into a flow along the upward movement area of the timing chain, and is efficiently conveyed to the first cam sprocket side by the upward movement area of the circulating timing chain. Further, it is guided along the chain guide by the inward movement region of the timing chain that circulates and is carried to the chain sprocket side and returned to the oil reservoir. As a result, the oil in the oil reservoir chamber is relatively secured without excessive oil remaining in the valve operating chamber, and a reduction in the lubrication efficiency due to the deterioration of oil return is avoided. Further, the improved lubrication efficiency can reduce the rated amount of oil, and the engine can be reduced in size and weight.

  According to a second aspect of the present invention, in the engine oil circulation structure according to the first aspect, the upper portion of the first oil rectifying means is between the axis of the first cam shaft and the axis of the second cam shaft. The bead is provided in the chain chamber extending along the rising movement region of the timing chain, the lower end approaching the second camshaft, and the top edge facing the side surface of the second cam sprocket. Features.

  According to the present invention, the first oil rectifying means has an upper portion extending along the rising movement region of the timing chain between the shaft center of the first cam shaft and the shaft center of the second cam shaft, and a lower end of the second oil cam means. It can be formed with a simple configuration by a bead provided in a chain chamber that is close to the shaft and whose top edge faces the side surface of the second cam sprocket.

  According to a third aspect of the present invention, in the oil circulation structure of the engine according to the first or second aspect, the chain chamber is formed by a front surface of the cylinder block and the cylinder head and a chain cover covering the front surface, and the first oil rectification The upper portion extends along the rising movement region of the timing chain between the axis of the first cam shaft and the axis of the second cam shaft, and the lower end approaches the second cam shaft. A top bead is provided with a first bead integrally formed with the chain cover facing the outer surface of the second cam sprocket.

  According to this invention, since the first oil rectifying means is formed by the first bead integrally formed on the chain cover forming the chain chamber, the first oil rectifying means can be formed without increasing the number of components. .

  According to a fourth aspect of the present invention, in the engine oil circulation structure according to any one of the first to third aspects, the chain chamber is formed by a front surface of the cylinder block and the cylinder head and a chain cover that covers the front surface. The first oil rectifying means has an upper portion extending along the rising movement region of the timing chain between the axis of the first cam shaft and the axis of the second cam shaft, and a lower end of the first oil rectifying means. And a second bead integrally formed on the front surface of the cylinder head, which approaches the two cam shafts and whose top edge faces the inner surface of the second cam sprocket.

  According to this invention, since the first oil rectifying means is formed by the second bead integrally formed on the front surface of the cylinder head forming the chain chamber, the first oil rectifying means is formed without increasing the number of components. Can do.

  According to a fifth aspect of the present invention, in the oil circulation structure of the engine according to any one of the first to fourth aspects, the oil in a direction that scatters in the chain chamber by a centrifugal force accompanying the rotation of the first cam sprocket. There is provided a second oil rectifier that blocks the flow and rectifies the oil flow along the inward movement region of the timing chain.

  According to this invention, in addition to the invention of any one of claims 1 to 4, the oil carried to the first cam sprocket side by the ascending movement region of the circulating timing chain is accompanied by the rotation of the first cam sprocket. Scattering due to centrifugal force is suppressed and the flow is rectified into a flow along the inward movement region of the timing chain. Therefore, the oil flow can be efficiently guided to the inward movement region of the timing chain and the chain sprocket side.

  According to a sixth aspect of the present invention, in the engine oil circulation structure according to the fifth aspect, the second oil rectifier extends in the extending direction of the inward movement range of the timing chain above the first cam sprocket. An oil guide plate is provided.

  According to the present invention, the second oil rectifying means can be formed by the oil guide plate extending in the extending direction of the inward movement range of the timing chain above the first cam sprocket.

  According to the present invention, when the acceleration acts on the engine and the oil flows into the valve chamber from the oil reservoir chamber side, excess oil that has flowed into the valve chamber flows out from the oil communication path into the chain chamber. In the chain chamber, the first oil rectifying means cuts off the oil flow that moves around the second cam sprocket. Further, the oil flow is rectified into a flow along the rising movement region of the timing chain, and is efficiently conveyed to the chain sprocket side by the circulating timing chain and returned to the oil reservoir. As a result, the oil in the oil reservoir chamber is relatively secured without excessive oil remaining in the valve operating chamber, and a reduction in the lubrication efficiency due to the deterioration of oil return is avoided.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  1 is a front view of the engine with the chain cover removed, and FIG. 2 is a schematic sectional view taken along line II-II in FIG. In FIG. 1, for convenience of explanation, the first rib of the first oil rectifier and the oil guide plate of the second oil rectifier provided on the chain cover are illustrated. Further, in FIG. 2, an arrow Fr indicates a forward direction in a state of being mounted on the vehicle.

  In the figure, reference numeral 1 denotes an engine having a plurality of banks. In this embodiment, a horizontally opposed engine is shown. The cylinder block 2 of the engine 1 has a crankcase integrally, and extends to the left bank side (hereinafter abbreviated as “LH”) cylinder block 2a and right bank side (hereinafter abbreviated as “LH”) centering on the crankshaft 12. The cylinder block 2b is abbreviated as “RH” hereinafter.

  An oil pan 4 is provided at the bottom of the cylinder block 2, and an oil reservoir 5 is formed by the oil pan 4 and the crankcase bottom of the cylinder block 2. On the other hand, an LH cylinder head 7 and an RH cylinder head 8 are attached to the LH and RH cylinder blocks 2a and 2b, respectively. An oil reservoir 5 and LH valve chambers 7a and RH valve chambers 8a formed in the cylinder heads 7 and 8 are formed in the cylinder heads 7 and 8 and the LH and RH cylinder blocks 2a and 2b, respectively. The LH oil return passage 2c and the RH oil return passage 2d communicate with each other.

  Further, a chain cover 10 is provided over the front surface 2e of the cylinder block 2 and the front surfaces 7e and 8e of the LH and RH cylinder heads 7 and 8, and the front surface of the cylinder block 2 and the front surfaces of the LH and RH cylinder heads 7 and 8 are provided. A chain chamber 11 is formed by 7e, 8e and the chain cover 10.

  On the front surface 2e of the cylinder block 2 covered with the chain cover 10, a crank gear 13 mounted on the end of the crank shaft 12, an idler sprocket 14 disposed above the crank gear 13, and the cylinder heads 7, 8 are provided. Intake side cam sprockets 19 and 20 and exhaust side cam sprockets 21 and 22 mounted on shaft ends of intake cam shafts 15 and 16 and exhaust cam shafts 17 and 18 respectively disposed in the valve operating chambers 7a and 8a. Is placed. The idler sprocket 14 is integrally formed with a driven gear 14a meshing with the crank gear 13 and sprockets 14b and 14c around which the LH timing chain 23 and the RH timing chain 27 are wound.

  An LH timing chain 23 is wound around the idler sprocket 14 and the intake side cam sprocket 19 and the exhaust side cam sprocket 21 provided on the LH cylinder head 7. A chain tensioner that adjusts the tension of the LH timing chain 23 by pressing against the LH timing chain 23 between the idler sprocket 14 and the exhaust side cam sprocket 21 and between the intake side cam sprocket 19 and the exhaust side cam sprocket 21. 24 is arranged. Further, chain guides 25 and 26 are disposed between the idler sprocket 14 and the intake side cam sprocket 19 and between the intake side cam sprocket 19 and the exhaust side cam sprocket 21. The chain tensioner 24 and the chain guides 25 and 26 are attached to and supported by the front surface 2e of the cylinder block 2 and the front surface 7e of the LH cylinder head 7.

  The idler sprocket 14 is rotated by the rotation of the crankshaft 12 through the crank gear 13, and the rotation of the idler sprocket 14 is transmitted to the cam sprockets 19 and 21 of the LH cylinder head 7 by the LH timing chain 23. As a result, the camshafts 15 and 17 of the LH cylinder head 6 are rotated in synchronization with the crankshaft 12.

  Further, an RH timing chain 27 is wound around the idler sprocket 14 and the intake side cam sprocket 20 and the exhaust side cam sprocket 22 provided on the RH cylinder head 8, and between the idler sprocket 14 and the exhaust side cam sprocket 22. Further, chain guides 29 and 30 are disposed between the intake side cam sprocket 20 and the exhaust side cam sprocket 22. A chain tensioner 28 that presses against the RH timing chain 27 and adjusts the tension of the RH timing chain 27 is disposed between the intake cam sprocket 20 and the idler sprocket 14. The chain tensioner 28 and the chain guides 29 and 30 are attached to and supported by the cylinder block 2 and the front surface 8e of the RH cylinder head 8.

  The idler sprocket 14 is rotated by the rotation of the crankshaft 12 through the crank gear 13, and the rotation of the idler sprocket 14 is transmitted to the cam sprockets 20 and 22 of the RH cylinder head 8 by the RH timing chain 27. As a result, the camshafts 16 and 18 of the RH cylinder head 8 are rotated in synchronization with the crankshaft 12.

  The crankshaft 12 is set to rotate in the clockwise direction in FIG. In other words, the LH timing chain 23 is guided from the idler sprocket 14 to the chain tensioner 24 to the exhaust side cam sprocket 21 of the LH cylinder head 7 along the raised lower surface 11a of the chain chamber 11, and further from the exhaust side cam sprocket 21 to the chain. Guided by the guide 25 to the intake side cam sprocket 19 along the side surface 11b of the chain chamber 11, and guided from the intake side cam sprocket 19 to the chain guide 26 to reach the idler sprocket 14 along the upper surface 11c of the chain chamber 11. Circulate in a clockwise direction. In this LH timing chain 23, the range from the idler sprocket 14 to the exhaust cam sprocket 21 along the lower surface 11a of the chain chamber 11 is the outward movement region 23A, and the intake air from the exhaust cam sprocket 21 along the side surface 11b of the chain chamber 11 The range reaching the side cam sprocket 19 is the ascending movement region 23B, and the range reaching the idler sprocket 14 from the intake side cam sprocket 19 along the upper surface 11c of the chain chamber 11 is the inward movement region 23C.

  On the other hand, the RH timing chain 27 is guided from the idler sprocket 14 to the chain tensioner 28 to the intake side cam sprocket 20 of the RH cylinder head 8 along the upper surface 11 d of the chain chamber 11, and from the intake side cam sprocket 20 to the chain guide 29. It is guided to the exhaust side cam sprocket 22 along the side surface 11 e of the chain chamber 11, and further circulates in the counterclockwise direction from the exhaust side cam sprocket 22 to the chain guide 30 to reach the idler sprocket 14. In this RH timing chain 27, the range from the idler sprocket 14 to the intake side cam sprocket 20 is the outward movement region 27A, and the range from the intake side cam sprocket 20 to the exhaust side cam sprocket 22 is the downward movement region 27B, and the exhaust side cam sprocket 22 The range from the first to the idler sprocket 14 is the inward movement region 27C.

  Further, the lower end of the chain chamber 11 and the oil reservoir 5 are communicated with each other via an oil return passage 32 formed in the cylinder block 2b, and the oil at the same level as the oil reservoir 5 is stored at the bottom of the chain chamber 11. Is done.

  In this case, an oil pump (not shown) that sucks the oil stored in the oil chamber 5 and supplies the oil to the necessary lubrication site via an oil gallery or the like is directly connected to the crankshaft 12.

  The valve operating chamber 7 a of the LH cylinder head 7 is communicated with the chain chamber 11 via an oil communication path 33 formed in the LH cylinder head 7 between the intake cam shaft 15 and the exhaust cam shaft 17. The valve operating chamber 8 a of the RH cylinder head 8 communicates with the chain chamber 11 through an oil communication path 34 formed in the RH cylinder head 8 between the intake cam shaft 16 and the exhaust cam shaft 18.

  In the chain chamber 11, the oil flows around the exhaust cam sprocket 21 into the ascending movement region 23 </ b> B of the LH timing chain 23 extending from the outside of the exhaust cam shaft 17 on the LH cylinder head 7 side toward the intake cam shaft 15. The first oil rectifying means 35 is provided for blocking the flow and rectifying the oil flow along the upward movement region 23B of the LH timing chain 23.

  The first oil rectifying means 35 is shown in FIG. 3 as an A-part enlarged view of FIG. 1, in FIG. 4 as an IV-IV line enlarged sectional view of FIG. 2, and as shown in FIG. As shown, the first rib 36 protruding from the inner surface 10a of the chain cover 10 along the ascending movement region 23B of the LH timing chain 23 and the ascending movement region 23B of the LH timing chain 23 on the front surface 7e of the LH cylinder head 7 are shown. The second rib 37 is provided so as to project along the line.

  The first rib 36 integrally formed with the inner surface 10a of the chain cover 10 has an upper portion 36a along the upward movement region 23B of the LH timing chain 23 between the axis of the intake camshaft 15 and the axis of the exhaust camshaft 17. Extend. Further, the lower end 36 b is bent or curved toward the exhaust cam shaft 17 and approaches the exhaust cam shaft 17. Further, the top edge 36 c faces the outer surface 21 a of the exhaust side cam sprocket 21.

On the other hand, the second rib 37 formed on the front surface 7e of the LH cylinder head 7 has an upper portion 37a between the axis of the intake camshaft 15 and the axis of the exhaust camshaft 17, and the ascending movement region 23B of the LH timing chain 23. Extending along. Further, the lower end 37 b is bent or curved toward the exhaust cam shaft 17 and approaches the exhaust cam shaft 17.
Furthermore, the top edge 37 c faces the inner side surface 21 b of the exhaust side cam sprocket 21. The first ribs 36 and the second ribs 37 can be easily formed without adding any constituent members by being integrally formed with the chain cover 10 and the LH cylinder head 7, respectively.

  That is, the exhaust-side sprocket 21 protrudes from the inner surface 10 a of the chain cover 10 and extends along the rising movement range 23 B of the LH timing chain 23 and the front edge 7 e of the LH cylinder head 7. And is arranged between the top edge 37c of the second rib 37 extending along the ascending movement range 23B of the LH timing chain 23.

  In addition, oil that splashes outward due to the centrifugal force of the intake cam sprocket 19 is blocked above the intake cam sprocket 19 on the LH cylinder head 7 side, and oil along the inward movement region 23C of the LH timing chain 23 A second oil rectifying means 38 for rectifying the flow is provided.

  As shown in FIGS. 3, 4 and 5, the second oil rectifying means 38 is continuous with the chain guide 26 along the upper surface 11 c between the upper surface 11 c of the chain chamber 11 and the intake side cam sprocket 19. A plate-like oil guide plate 39 that extends and covers the intake cam sprocket 19 is provided, and the oil guide plate 39 is fixed to a protrusion 10b that protrudes from the inner surface 10a of the chain cover 10 by a bolt 10c. . The inner end 39 a of the oil guide plate 39 is disposed close to the outer end 26 a of the chain guide 26.

  Next, the operation of the present embodiment will be described with the above configuration. When the engine is operated, an oil pump connected to the crankshaft 12 sucks oil stored in the oil reservoir 5 and supplies it to a necessary lubrication site inside the engine via an oil gallery or the like.

  At the same time, the idler sprocket 14 that meshes with the crank gear 13 mounted on the crankshaft 12 rotates in the direction opposite to the crank gear 13. The LH timing chain 23 wound around the idler sprocket 14 circulates and moves counterclockwise in FIG. 1, and the oil staying at the bottom of the chain chamber 11 is moved along the upward movement range 23B of the LH timing chain 23. The first rib 36 and the second rib 37 that extend are guided and conveyed upward. Further, an oil flow that is guided to the vicinity of the idler sprocket 14 by being guided by the oil guide plate 39 and the chain guide 26 that extend along the inward movement region 23C of the LH timing chain 23 is generated. On the other hand, the RH timing chain 27 circulates and moves in the counterclockwise direction in FIG. 1 opposite to the crankshaft 12, and an oil flow that carries the oil staying at the bottom of the chain chamber 11 to the oil return passage 32 is generated.

  Here, when a lateral acceleration (lateral G) in the right direction is applied due to left turn traveling or the like and flows into the valve operating chamber 8a of the RH cylinder 8 from the oil reservoir 5 side, a part of the inflowed oil is RH. The oil is returned to the oil reservoir 5 through the oil return passage 2d, and the remaining oil in the valve operating chamber 8a flows out from the oil communication passage 34 into the chain chamber 11. The oil that has flowed out of the oil communication passage 34 into the chain chamber 11 is guided downward by a downward movement region 27B that descends from the intake cam sprocket 20 side of the circulating RH timing chain 27 along the side surface 11e of the chain chamber 11. Further, it is guided to the oil return passage 32 side along the lower surface 11f by the inward movement region 27C that travels along the lower surface 11f of the chain chamber 11 from the exhaust side cam sprocket 22 side. Returned to chamber 5. As a result, the oil in the oil reservoir 5 is relatively secured without excessive oil accumulation in the valve operating chamber 8a, and air suction is generated in the oil pump, and deterioration in lubrication efficiency due to deterioration of oil return is avoided. Is done.

  On the other hand, when a lateral acceleration in the left direction is applied due to a right turn traveling or the like and flows into the valve operating chamber 7a of the LH cylinder head 7 from the oil reservoir chamber 5, a part of the excess oil that flows in is LH. The oil is returned to the oil reservoir 5 through the oil return passage 2c, and the remaining oil in the valve operating chamber 7a flows out from the oil communication passage 33 into the chain chamber 11.

  Here, the oil staying in the lower part on the LH cylinder head 7 side in the chain chamber 11 is separated from the exhaust side cam sprocket 21 by the oil flowing around the exhaust cam sprocket 21 as indicated by an arrow F in FIG. The first oil rectifying means 35 disposed opposite to each other is blocked by the first rib 36 and the second rib 37. As a result, the oil flow is changed between the first rib 36 and the second rib 37 and the side surface 11b of the chain chamber 11 to a flow rising along the rising movement region 23B of the LH timing chain 23, and the first rib 36 And it is guided to the second rib 37 and carried to the intake side cam sprocket 19 side. The flow rate of the oil carried by the ascending movement region 23B of the LH timing chain 23 is secured by a decrease in the accompanying rotation of the exhaust side cam sprocket 21, and a high flow rate is maintained to ensure the intake side cam sprocket 19 side. Carried to.

  On the other hand, the oil carried to the intake side cam sprocket 19 side tends to scatter from the intake side cam sprocket 19 by the centrifugal force accompanying the rotation of the intake side cam sprocket 19. However, scattering from the intake cam sprocket 19 is suppressed by being received by the oil guide plate 39 of the second oil rectifier 38 disposed above the intake cam sprocket 19, and the inward movement region 23C of the LH timing chain 23 is suppressed. Is guided to the chain guide 26 side. Further, the oil guide plate 39 extending along the inward movement region 23C of the LH timing chain 23 is carried to the lower surface side of the chain guide 26, conveyed to the vicinity of the idler sprocket 14, and passed through the oil return passage 32 to be stored in the oil reservoir chamber. Returned to 5. A broken line L in FIG. 3 indicates the oil level in the chain chamber 11. As a result, oil in the oil reservoir chamber 5 is relatively secured without excessive oil accumulation in the valve operating chamber 7a, and air suction or oil return occurs in the oil pump without increasing the rated capacity of the oil. A decrease in the lubrication efficiency due to the deterioration is avoided.

  For comparison with the present embodiment, a comparative example that does not include the first oil rectifier 35 and the second oil rectifier 38 will be described with reference to FIG.

  When a lateral acceleration in the left direction is applied due to a right turn or the like and flows into the valve chamber 7a of the LH cylinder 7 from the oil reservoir 5 side, a part of the excess oil flows in the LH oil return passage. The oil is returned to the oil reservoir 5 through 2c, and the oil in the remaining valve operating chamber 7a flows out from the oil communication passage 33 into the chain chamber 11.

  Here, a large amount of oil staying on the LH cylinder head 7 side in the chain chamber 11 is accompanied by the exhaust side cam sprocket 21 as indicated by an arrow F, and the amount of oil that is accompanied by the exhaust side cam sprocket 21 is increased. Accordingly, the amount of oil carried to the intake-side cam sprocket 19 side along the ascending movement region 23B of the LH timing chain 23 is small, and the flow velocity is also slowed. Further, the oil carried to the intake side cam sprocket 19 side is scattered from the intake cam sprocket 19 by the centrifugal force accompanying the rotation of the intake side cam sprocket 19 and flows along the upper surface 11c of the chain chamber 11, and the chain guide 26 and the upper surface 11c. Sent between. The oil sent to the upper side of the chain guide 26 loses the flow velocity without being imparted with the conveying force by the inward movement region 23C of the LH timing chain 23, falls down and is conveyed to the idler sprocket 14 side. As a result, the amount of oil remaining on the LH cylinder head 7 side in the chain chamber 11 increases. A broken line L in FIG. 6 indicates the position of the oil level in the chain chamber 11.

  Oil that has accumulated excessively in the valve operating chamber 7a due to an increase in the oil remaining in the chain chamber 11 is prevented from flowing out to the chain chamber 11 via the oil communication path 33, and the oil amount in the oil reservoir 5 is relatively increased. As a result, the oil pump sucks air, and there is a concern that the lubrication efficiency may decrease due to the deterioration of oil return. In addition, the exhaust side cam sprocket 21 increases the oil agitation resistance due to the increase in the amount of oil accompanying the oil, causing the deterioration of the oil and causing the deterioration of the fuel consumption.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of invention. For example, in the above embodiment, the first rectifying means 35 is formed by the first rib 36 protruding from the inner surface 10 a of the chain cover 10 and the second rib 37 protruding from the front surface 7 e of the LH cylinder head 7. It can be formed by an oil guide plate that is bolted to the inner surface 10a or the front surface e of the LH cylinder head 7.

  Further, although the second rectifying means 38 is formed by the oil guide plate 39 bolted to the chain cover 10, the oil guide plate 39 may be bolted to the front surface 7 e of the LH cylinder head 7. Can also be formed by ribs protruding from the inner surface 10a of the chain cover 10 or the front surface 7e of the LH cylinder head 7. The first rectifying means 35 and the second rectifying means 38 are preferably changed in size and shape as appropriate by experiments, simulations, etc. according to engine specifications and the like.

  Further, in this embodiment, a crank gear is mounted on the crankshaft, and the intake side sprocket and the exhaust side sprocket disposed in each bank are rotationally driven by circulating the LH and RH timing chains via idler sprockets. As an example, an intake side sprocket and an exhaust mounted on each bank by mounting a crank sprocket on a crankshaft without an idler sprocket and winding LH and RH timing chains by the crank sprocket. The present invention can be applied to an engine of a type that rotationally drives a side sprocket.

  Furthermore, although the example applied to the horizontally opposed engine has been described in the present embodiment, it can also be applied to a V-type engine or the like as an engine having a plurality of banks. Further, the present invention is not limited to an engine having a plurality of banks, and may be applied to, for example, an inclined engine or a horizontally-arranged in-line engine having a relatively small difference in height between an oil reservoir chamber and a valve operating chamber. Furthermore, the present invention can also be applied to engines other than vehicles such as general-purpose engines.

It is a front view of the engine which removed the chain cover concerning one embodiment of the present invention. FIG. 2 is a schematic sectional view taken along line II-II in FIG. 1. It is the A section enlarged view of FIG. It is the IV-IV line expanded sectional view of FIG. It is a LH cylinder head principal part enlarged view. It is comparative explanatory drawing.

Explanation of symbols

1 Engine 2 Cylinder block 2a LH cylinder block 2b RH cylinder block 2c LH oil return passage 2e Front wall surface 5 Oil reservoir chamber 7 LH cylinder head 7a LH valve chamber 8 RH cylinder head 8a RH valve chamber 10 Chain cover 11 Chain chamber 12 Crankshaft 13 Crank gear 14 Idler sprocket (chain sprocket)
14a Driven gears 14b, 14c Sprockets 15, 16 Intake camshaft (first camshaft)
17, 18 Exhaust cam shaft (second cam shaft)
19, 20 Intake side cam sprocket (first cam sprocket)
21, 22 Exhaust side cam sprocket (second cam sprocket)
21a Outer side surface 21b Inner side surface 23 LH timing chain 24 Chain tensioner 25, 26 Chain guide 32 Oil return path 33 Oil communication path 35 First oil rectifier 36 First rib 36a Upper part 36b Lower end 36c Top edge 37 Second rib 37a Upper part 37b Lower end 37c Top edge 38 Second oil rectifying means 39 Oil guide plate

Claims (6)

A first cam sprocket and a second cam sprocket respectively disposed on a first camshaft and a second camshaft disposed in a valve operating chamber provided in the cylinder head, a chain sprocket driven by a crankshaft, An outwardly moving region from the chain sprocket to the second cam sprocket wound around the sprocket, an upwardly moving region from the second cam sprocket to the first cam sprocket, and from the second cam sprocket to the chain sprocket A timing chain that circulates in circulation, a chain chamber that houses a chain guide that extends along the upper side of the inward movement range of the timing chain between the chain sprocket and the first cam sprocket, and a cylinder block With an oil reservoir in the bottom In the engine,
The chain chamber and the oil reservoir chamber communicate with each other via an oil return passage, and the chain chamber and the valve train chamber communicate with each other via an oil communication passage.
An engine is provided with a first oil rectifying means for blocking the flow of oil around the second cam sprocket in the chain chamber and for rectifying the flow of oil along the rising movement region of the timing chain. Oil circulation structure. The first oil rectifying means includes:
The upper part extends along the rising movement region of the timing chain between the axis of the first cam shaft and the axis of the second cam shaft, the lower end approaches the second cam shaft and the top edge is The engine oil circulation structure according to claim 1, wherein the engine oil circulation structure is a bead provided in the chain chamber facing a side surface of the second cam sprocket. The chain chamber is formed by a front surface of the cylinder block and the cylinder head, and a chain cover that covers the front surface,
The first oil rectifying means includes:
The upper part extends along the rising movement region of the timing chain between the axis of the first cam shaft and the axis of the second cam shaft, the lower end approaches the second cam shaft and the top edge is 3. The engine oil circulation structure according to claim 1, further comprising a first bead integrally formed with the chain cover facing an outer surface of the second cam sprocket. 4. The chain chamber is formed by a front surface of the cylinder block and the cylinder head, and a chain cover that covers the front surface,
The first oil rectifying means includes:
The upper part extends along the rising movement region of the timing chain between the axis of the first cam shaft and the axis of the second cam shaft, the lower end approaches the second cam shaft and the top edge is The engine oil circulation structure according to any one of claims 1 to 3, further comprising a second bead integrally formed on a front surface of the cylinder head facing an inner surface of the second cam sprocket. .   Second oil rectifying means for blocking the flow of oil in the direction scattered by the centrifugal force accompanying the rotation of the first cam sprocket in the chain chamber and rectifying the flow of oil along the inward movement region of the timing chain The oil circulation structure for an engine according to any one of claims 1 to 4, wherein the engine oil circulation structure is provided. The second oil rectifying means is
6. The engine oil circulation structure according to claim 5, further comprising an oil guide plate extending in an extending direction of an inward movement range of the timing chain above the first cam sprocket.

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