JP3748007B2 - Engine oil relief structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine oil relief structure, and more particularly to an engine oil relief structure that can lubricate a timing chain and a sprocket using oil discharged from a hydraulic control valve of a hydraulic control device.
[0002]
[Prior art]
An engine mounted on a vehicle or the like is provided with a valve system, an auxiliary machine, a hydraulic control device, and the like. These valve trains, auxiliary machines, hydraulic control devices, etc. are supplied with oil discharged from an oil pump to perform lubrication, operation and control. The hydraulic control device of the engine controls the hydraulic operation device by controlling the oil discharged from the oil pump to the hydraulic operation device by controlling the hydraulic control valve.
[0003]
The hydraulic control valve controls oil supplied from an oil pump and oil supplied to and discharged from a hydraulic control device, and causes unnecessary oil to flow out from the relief hole and return to the oil pan.
[0004]
As an oil relief structure of such an engine, there are those shown in FIGS. 11 to 13 , 202 is an engine, 204 is a cylinder block, 206 is a cylinder head, 208 is a head cover, 210 is an oil pan, 212 is a crankshaft, 214 is an intake camshaft, 216 is an exhaust camshaft, and 218 is a timing A chain 220 is a chain cover.
[0005]
The engine 202 is provided with a timing chain 218 that transmits the rotation of the crankshaft 212 to the intake and exhaust camshafts 214 and 216, and a chain cover is attached to the cylinder block 204 and the cylinder head 206 so as to cover the timing chain 218. A chain chamber 222 is formed.
[0006]
The engine 202 is provided with a variable valve timing device 224 that varies the valve timing of intake and exhaust valves (not shown) as a hydraulic control device. The variable valve timing device 224 is provided with a hydraulic actuator 226 which is a hydraulic operation device attached to one end side of the intake camshaft 216, and a hydraulic control valve 228 for supplying and discharging oil to the hydraulic actuator 226 is provided on the outer surface of the chain cover 220. 230 is provided.
[0007]
The variable valve timing device 224 controls the hydraulic control valve 228 according to the operating state of the engine 202 by a control means (not shown), and the oil discharged from the oil pump 232 is advanced and retarded by the hydraulic control valve 228. The oil is distributed to oil and supplied to the hydraulic actuator 226, and the phase of the intake camshaft 214 with respect to the crankshaft 212 is changed to vary the valve timing of the intake and exhaust valves.
[0008]
Oil discharged from the oil pump 232 driven by the crankshaft 212 flows into the hydraulic control valve 228 through the oil pipe 234. The oil that has flowed into the hydraulic control valve 228 includes a cover-side advance oil passage 236 and a cover-side retard oil passage 238 provided in the chain cover 220, a head-side advance oil passage 240 provided in the cylinder head 206, and The hydraulic actuator 226 is supplied and discharged by a head side retard oil passage 242, a cam shaft side advance oil passage 244 provided on the intake cam shaft 214, and a cam shaft side retard oil passage 246.
[0009]
As described above, the chain cover 220 is provided with at least a part of the oil passages 234 to 246 through which oil flows into and out of the hydraulic control valve 228. The hydraulic control valve 228 controls the oil supplied from the oil pump 232 and the oil supplied to and discharged from the hydraulic actuator 226, and discharges unnecessary oil from the relief hole 248 as shown in FIG. Return to pan 210. The relief hole 248 is provided on the inner side surface 250 of the chain cover 220.
[0010]
Such engine oil relief structures include those disclosed in JP-A-6-307210, JP-A-10-121918, and JP-A-10-184331.
[0011]
JP-A-6-307210 discloses a first and second oil chambers defined by a piston in a piston storage chamber of a valve opening / closing timing control device formed between a camshaft and a timing pulley. The first and second oil chambers are provided with a hydraulic control valve for supplying and discharging oil supplied by the hydraulic pressure supply means, and a relief passage for allowing the oil in the first chamber to flow into the cam chamber is provided.
[0012]
Japanese Patent Laid-Open No. 10-121918 discloses that oil discharged from the drain hole of the drain passage of the hydraulic control valve of the valve timing changing mechanism is returned from the oil drop part of the cylinder head to the oil pan through the drain hole. In the valve characteristic control device, a weir for restricting the mixed flow of oil other than the oil discharged to the oil dropping portion is provided around the drain hole of the drain passage.
[0013]
Japanese Patent Application Laid-Open No. 10-184331 has an oil control valve for a variable valve timing device provided in a cam cap of a cylinder head, and an oil drain hole for returning return oil from the oil control valve to the cam chamber. Is.
[0014]
[Problems to be solved by the invention]
Incidentally, in the conventional oil relief structure of the engine 202 shown in FIGS. 11 to 13, a relief hole 248 is provided in order to return the oil discharged from the hydraulic control valve 228 to the oil pan 210.
[0015]
However, the oil hole 248 is provided at a position away from the timing chain 218 on the inner surface 250 of the chain cover 220 as shown in FIG. As a result, the oil discharged from the relief hole 248 to the chain chamber 222 flows down along the inner side surface 250 of the chain cover 220 and the block side surface 252 of the cylinder block 204 that are separated from the timing chain 218 and is returned to the oil pan 210. It will be.
[0016]
Therefore, in the oil relief structure of the engine 202, oil discharged from the relief hole 248 to the chain chamber 222 is used for lubricating the timing chain 218 and a sprocket (not shown) around which the timing chain 218 is wound. There is a problem that can not be.
[0017]
As a result, in the oil relief structure of the engine 202, a dedicated oil supply means for lubricating the timing chain 218 and the sprocket has to be provided separately, resulting in an increase in cost.
[0018]
[Means for Solving the Problems]
Accordingly, the present invention is to eliminate the disadvantages described above, a timing chain for transmitting rotation of a crankshaft of an engine mounted on a vehicle intake and exhaust cam shaft is provided, the inner peripheral shape tight side of the timing chain A linear cover is formed on the loose side to transmit the rotation of the crankshaft to the intake / exhaust camshaft, while a chain cover is attached to the cylinder block and the cylinder head so as to cover the timing chain and is driven by the crankshaft. An oil pump is provided, a hydraulic control valve is provided for controlling a hydraulic operation device of the hydraulic control device, and oil discharged from the oil pump is sent to the hydraulic operation device via the hydraulic control valve in an oil passage, The oil discharged from the oil pump is discharged from a relief hole provided in the oil passage, and the timing check is performed. An oil relief structure for an engine for lubricating down, the hydraulic control valve incorporates an oil the oil pump is discharged through the oil inlet disposed upstream of the hydraulic control valve, the opening area of the oil inlet, the When the hydraulic control valve is viewed from the inner periphery of the timing chain and from the center of the crankshaft, the hydraulically operated device is made wider than the area of the oil passage leading from the hydraulic control valve to the hydraulically operated device. It is located below and closer to the tight side of the timing chain than the middle of the intake / exhaust camshaft, the relief hole is in the vicinity of the inner periphery of the timing chain, and the oil discharged from the relief hole is placed inside the timing chain. A guide portion for guiding the periphery is provided in the relief hole, and the guide portion supplies oil to the timing chain. It is curved tip to direct the inner peripheral portion of the, and wherein the sending toward the tight side of the oil to the timing chain from the relief holes at the rotation of the crankshaft.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
The oil relief structure of the engine according to the present invention can positively supply the oil discharged from the relief hole to the inner peripheral portion of the timing chain meshing with the sprocket.
[0020]
【Example】
Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show a first embodiment of the present invention. 4 to 6, 2 is an engine mounted on a vehicle (not shown), 4 is a cylinder block, 6 is a cylinder head, 8 is a head cover, 10 is an oil pan, 12 is a crankshaft, and 14 is a chain cover. . In the engine 2, a crankshaft 12 is pivotally supported at the lower part of the cylinder block 4, and an oil pan 10 is attached so as to cover the crankshaft 12.
[0021]
Further, the engine 2 has a cylinder head 6 attached to the upper part of the cylinder block 4, and suction / exhaust cam shafts 16, 18 that open and close a suction / exhaust valve (not shown) on the cylinder head 6. The head cover 8 is attached so as to be supported by the shafts 20 and 22 and to cover the intake and exhaust camshaft caps 20 and 22.
[0022]
A crank timing sprocket 24 is attached to the crankshaft 12 on one end side. Suction / exhaust cam sprockets 26, 28 are attached to the suction / exhaust cam shafts 16, 18 on one end side. A timing chain 30 is wound around the crank timing sprocket 24 and the intake / exhaust cam sprockets 26 and 28.
[0023]
The chain cover 14 is attached to one end of the cylinder block 4 and the cylinder head 6 in the longitudinal direction so as to cover the crank timing sprocket 24, the intake / exhaust cam sprockets 26 and 28, and the timing chain 30, thereby forming a chain chamber 32. is doing.
[0024]
Further, a water pump 38, an alternator 40, a power steering oil pump 42, and an air conditioner compressor 44 are attached to the engine 2 as a plurality of auxiliary machines driven by the crankshaft 12, and a belt tensioner 46 is attached to the chain cover 14. Is provided.
[0025]
In the engine 2, an oil pump 48 driven by the crankshaft 12 is provided in the chain cover 14. As shown in FIGS. 1 and 3, the oil pump 48 has an inner rotor and an outer rotor (not shown) that are rotatably incorporated in a pump housing 50 provided in the chain cover 14 and is rotated by the crankshaft 12. Oil in the pan 10 is sucked from the suction port 52 and discharged to the discharge port 54.
[0026]
As shown in FIG. 5, the oil discharged to the discharge port 54 flows into the sub gallery 56 through a relief valve (not shown), is filtered by an oil filter (not shown), and is supplied to the main gallery 58 of the cylinder block 4. Is done. The oil in the main gallery 58 is supplied to the drive system of the crankshaft 12, the intake / exhaust camshafts 16, 18, the valve operating system such as the intake / exhaust valve, and the auxiliary system such as the water pump 38. Reference numeral 60 denotes a water outlet pipe attached to the outer surface 62 of the chain cover 14.
[0027]
The engine 2 is provided with a variable valve timing device 64 as a hydraulic control device. As shown in FIG. 4, the variable valve timing device 64 is provided with a hydraulic actuator 66, which is a hydraulic operating device, attached to one end of the intake camshaft 16, and supplies oil discharged from the oil pump 48 to the hydraulic actuator 66. A hydraulic control valve 68 for discharging is attached to the outer surface 62 of the chain cover 14.
[0028]
As shown in FIG. 4, the hydraulic control valve 68 incorporates a spool valve (not shown) in the valve main body 70, and the mounting flange 72 is provided on the valve mounting boss 74 provided on the outer surface 62 of the chain cover 14. It is attached with a mounting bolt 76.
[0029]
As shown in FIG. 5, the main gallery 58 communicates one end of the crankshaft 16 in the axial direction with a cover communication hole 78 of the chain cover 14. One end side of the oil pipe 80 is connected to the cover communication hole 78 by a union bolt 82. The oil pipe 80 has an intermediate portion inserted under the belt tensioner 46 and the other end connected to the oil inlet 86 of the hydraulic control valve 68 by a union bolt 84.
[0030]
As shown in FIG. 1 and FIG. 3, the hydraulic control valve 68 uses the spool valve to supply oil taken from the oil inlet 86 to the advance oil outlet 88 and retard oil outlet 90 as advance oil and retard oil. Distribute. The advance oil outlet 88 and the retard oil outlet 90 are in communication with one end side of an advance oil passage 92 and a retard oil passage 94 provided in the chain cover 14.
[0031]
As shown in FIGS. 4 to 6, the advance oil passage 92 and the retard oil passage 94 are connected to one end side of the advance oil pipe 96 and the retard oil pipe 98 on the other end side. The other end sides of the advance oil pipe 96 and the retard oil pipe 98 are connected to the cap advance oil passage 100 and the cap retard oil passage 102 of the intake camshaft cap 20. The cap advance oil passage 100 and the cap retard oil passage 102 communicate with the hydraulic actuator 66 via the cam shaft advance oil passage 104 and the cam shaft retard oil passage 106 of the intake camshaft 16. Yes.
[0032]
The variable valve timing device 64 controls the hydraulic control valve 68 according to the operating state of the engine 2 by control means (not shown), introduces oil discharged from the oil pump 48 into the hydraulic control valve 68 through the oil pipe 80, and The hydraulic control valve 68 distributes the oil to advance oil and retard oil, and supplies / discharges the oil to / from the hydraulic actuator 66 through the oil advance passages and retard oil passages 92 to 106, and intake air to the crankshaft 12. The valve timing of the intake / exhaust valves is varied by changing the phase of the cam shaft 16.
[0033]
As described above, the chain cover 14 is provided with the advance oil passage 92 and the retard oil passage 94 as at least a part of the oil passages 80 and 92 to 106 for flowing oil into and out of the hydraulic control valve 68. .
[0034]
Further, the hydraulic control valve 68 controls the oil supplied from the oil pump 48 and the oil supplied to and discharged from the hydraulic actuator 66, and has a relief hole 108 for returning unnecessary oil to the oil pan 10. . As shown in FIGS. 1 and 3, the relief hole 108 is provided on the inner surface 110 of the chain cover 14.
[0035]
As shown in FIGS. 1 and 2, the oil relief structure of the engine 2 is configured such that the oil relief hole 108 discharged from the hydraulic control valve 68 is connected to the crank timing sprocket 24 and the suction / intake on the inner 110 surface of the chain cover 14. It is located near the inner periphery 112 of the timing chain 30 that meshes with the exhaust cam sprockets 26 and 28.
[0036]
The relief hole 108 is provided adjacent to the advance-forming oil outlet 88 and the outlet-forming boss 114 of the retard oil outlet 90 formed so as to protrude from the inner surface 110 of the chain cover 14. As a result, the inner surface 110 of the chain cover 14 is discharged from the relief hole 108 by using a part of the outlet forming boss portion 114 to be positioned on the side away from the timing chain 30 of the relief hole 108. A guide portion 116 that guides oil to the inner peripheral portion 112 of the timing chain 30 is provided.
[0037]
As a result, the oil relief structure of the engine 2 allows the oil discharged from the relief hole 108 into the chain chamber 32 by the relief hole 108 provided in the vicinity of the inner peripheral portion 112 of the timing chain 30. 14 without actively flowing down the inner side surface 110 of the cylinder 14 or the block side surface of the cylinder block 4 toward the inner peripheral portion 112 of the timing chain 30 that meshes with the crank timing sprocket 24 and the intake / exhaust cam sprockets 26, 28. While being able to supply, the guide 116 can actively guide the oil.
[0038]
For this reason, the oil relief structure of the engine 2 uses the oil discharged from the relief hole 108 to use the timing chain 30, the crank timing sprocket 24 around which the timing chain 30 is wound , the intake cam sprocket 26, the exhaust cam sprocket. 28 can be lubricated, the extension of the timing chain 30 can be reduced, and the wear of the timing chain 30, the crank timing sprocket 24, the intake cam sprocket 26, and the exhaust cam sprocket 28 can be reduced. The durability of the crank timing sprocket 24, the intake cam sprocket 26, and the exhaust cam sprocket 28 can be improved.
[0039]
Further, in the oil relief structure of the engine 2, there is no need to separately provide a dedicated oil supply means for lubricating the timing chain 30, the crank timing sprocket 24, the intake cam sprocket 26, and the exhaust cam sprocket 28 . Reduction can be achieved.
[0040]
7 and 8 show a second embodiment of the present invention. The oil relief structure of the second embodiment is a rib-shaped guide that is positioned on the side away from the timing chain 30 of the relief hole 108 and guides the oil discharged from the relief hole 108 to the inner peripheral portion 112 of the timing chain 30. A portion 116 is provided. The guide portion 116 is formed in a part of the cylindrical shape on the outlet forming boss portion 114 so as to surround the relief hole 108 toward the inner peripheral portion of the timing chain 30.
[0041]
Thus, the oil relief structure of the second embodiment is more aggressive than the first embodiment in that the oil discharged from the relief hole 108 is directed toward the inner peripheral portion 112 of the timing chain 30 by the partially cylindrical guide portion 116. The timing chain 30, the crank timing sprocket 24, the intake cam sprocket 26, and the exhaust cam sprocket 28 can be better lubricated. The timing chain 30, the crank timing sprocket 24, the intake cam sprocket 26, The durability of the exhaust cam sprocket 28 can be further improved.
[0042]
FIG. 9 shows a third embodiment of the present invention. In the oil relief structure of the third embodiment, a relief hole 108 for oil discharged from the hydraulic control valve 68 is provided in the vicinity of the inner peripheral portion 112 of the timing chain 30, and is provided in the inner peripheral portion 112 of the timing chain 30. Inclined so as to be oriented.
[0043]
Thereby, in the oil relief structure of the third embodiment, the oil discharged from the relief hole 108 is directed toward the inner peripheral portion 112 of the timing chain 30 by the relief hole 108 directed to the inner peripheral portion 112 of the timing chain 30. also can be supplied positively from the first embodiment, the timing chain 30 and the crank timing sprocket 24, the intake cam sprocket 26, it is possible to lubricate the exhaust cam sprocket 28 to better timing chain 30 and the crank timing sprocket 24, the durability of the intake cam sprocket 26 and the exhaust cam sprocket 28 can be further improved.
[0044]
FIG. 10 shows a fourth embodiment of the present invention. In the oil relief structure of the fourth embodiment, the oil relief hole 108 discharged from the hydraulic control valve 68 is provided in the vicinity of the inner peripheral portion 112 of the timing chain 30, and the oil discharged from the relief hole 108 is provided. Is provided on the outlet-forming boss 114, and the tip 118 of the guide 116 is directed to the inner periphery 108 of the timing chain 30. It is provided so as to be curved.
[0045]
Thus, in the oil relief structure of the fourth embodiment, the oil discharged from the relief hole 108 is absorbed in the timing chain 30 by the distal end portion 118 of the guide portion 116 that curves toward the inner peripheral portion 108 of the timing chain 30. It can supply more positively and reliably toward the peripheral portion 112 than in the first to third embodiments, and lubricates the timing chain 30, the crank timing sprocket 24, the intake cam sprocket 26, and the exhaust cam sprocket 28 even better. The durability of the timing chain 30, the crank timing sprocket 24, the intake cam sprocket 26, and the exhaust cam sprocket 28 can be further improved.
[0046]
In the above-described embodiment, the guide portion 116 is formed integrally with the chain cover 14. However, the guide portion 116 is integrally formed at a portion facing the relief hole 108 of the cylinder block 4 or the cylinder head 6. It can also be formed, and can also be formed by utilizing an existing boss portion or the like at a portion facing the relief hole 108 of the cylinder block 4 or the cylinder head 6. Further, an oil reservoir communicating with the relief hole 108 can be provided, and the oil accumulated in the oil reservoir can be blown out from the relief hole 108 toward the timing chain 30 when the engine 2 is rotating at high speed.
[0047]
【The invention's effect】
Thus, the oil relief structure of the engine of the present invention can positively supply the oil discharged from the relief hole to the inner peripheral portion of the timing chain that meshes with the sprocket.
[0048]
For this reason, the oil relief structure of this engine can lubricate the timing chain and the sprocket around which the timing chain is wound using the oil discharged from the relief hole, and can reduce the extension of the timing chain. The wear of the timing chain and the sprocket can be reduced, and the durability of the timing chain and the sprocket can be improved. Further, in this oil relief structure of the engine, it is not necessary to provide a dedicated oil supply means for lubricating the timing chain and the sprocket separately, and the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a rear view of a chain cover showing a first embodiment of an engine oil relief structure according to the present invention;
FIG. 2 is an enlarged cross-sectional view taken along line 2-2 of FIG.
FIG. 3 is a front view of a chain cover.
FIG. 4 is a partially broken front view of the engine.
FIG. 5 is a partially broken side view of the engine.
FIG. 6 is a plan view of the engine with the head cover removed.
FIG. 7 is a partial rear view of a chain cover showing a second embodiment.
8 is a cross-sectional view taken along line 8-8 of FIG.
FIG. 9 is a cross-sectional view of a relief hole portion of a chain cover showing a third embodiment.
FIG. 10 is a cross-sectional view of a relief hole portion of a chain cover showing a fourth embodiment.
FIG. 11 is a partially cutaway front view of an engine showing a conventional example of an oil relief structure.
FIG. 12 is a longitudinal sectional view of the engine.
FIG. 13 is a rear view of the chain cover.
[Explanation of symbols]
2 Engine 4 Cylinder block 6 Cylinder head 8 Head cover 12 Crankshaft 14 Chain cover 16 Intake camshaft 18 Exhaust camshaft 30 Timing chain 24 Crank timing sprocket 26 Intake cam sprocket 28 Exhaust cam sprocket 32 Chain chamber 48 Oil pump 62 Outer side 64 Variable Valve timing device 66 Hydraulic actuator 68 Hydraulic control valve 80 Oil pipe 86 Oil outlet 88 Advance oil outlet 90 Delay oil outlet 92 Advance oil passage 94 Delay oil passage 108 Relief hole 110 Inner side 112 Inner circumference 116 Guide part

Claims (1)

A timing chain that transmits the rotation of the crankshaft of the engine mounted on the vehicle to the intake / exhaust camshaft is provided, and the inner periphery of the timing chain is straightened from the loose side to absorb the rotation of the crankshaft. A chain cover attached to the cylinder block and the cylinder head is provided to cover the timing chain while transmitting to the exhaust camshaft, and an oil pump driven by the crankshaft is provided to control the hydraulic operation equipment of the hydraulic control device A hydraulic control valve is provided, and oil discharged from the oil pump is sent to the hydraulic actuator via the hydraulic control valve in the oil passage, while oil discharged from the oil pump is provided in the oil passage. It is discharged from the hole in the oil relief structure of the engine to lubricate the timing chain The hydraulic control valve, an oil communicating incorporating oil the oil pump is discharged through the oil inlet disposed upstream of the hydraulic control valve, the opening area of the oil inlet, the hydraulic device from the hydraulic pressure control valve While making the area of the passage larger than the area of the passage, when viewed from the center of the crankshaft on the inner periphery of the timing chain, the hydraulic control valve is located below the hydraulic actuator and between the intake and exhaust camshafts. Arranged near the tight side of the timing chain, the relief hole is in the vicinity of the inner periphery of the timing chain, and a guide portion that guides oil discharged from the relief hole to the inner periphery of the timing chain is the relief hole The guide portion is curved at the tip so that the oil is directed to the inner peripheral portion of the timing chain, Oil relief structure for an engine, characterized in that at rotation of the rank shaft sending toward the oil from the relief hole on tight side of the timing chain.

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