JP2004052707A - Engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable an engine to be made compact, the engine being arranged such that a first cam shaft having a power input portion at its one end and a second cam shaft connected to the first cam shaft at its one end so as to operate in linkage with the first cam shaft have axial lines parallel to each other and are rotatably supported by a cylinder head, and a driven gear engaging with a driving gear provided at the other end of one of the first and second cam shafts is provided on an auxiliary equipment driving shaft connected to an auxiliary equipment attached to an engine body including a cylinder head. <P>SOLUTION: An axial line of the auxiliary equipment driving shaft 71 is located between both cam shafts 31, 32 on the side of the cylinder head 11 with respect to a line extending between the axial lines of the first and the second cam shafts 31, 32. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
According to the present invention, a first camshaft having a power input portion at one end and a second camshaft having one end interlocked with and connected to the first camshaft have axes parallel to each other and are rotated by a cylinder head. A driven gear, which is freely supported and meshes with a drive gear provided at one of the other ends of the first and second camshafts, is connected to an accessory drive shaft connected to an accessory attached to the engine body including the cylinder head. The engine to be provided.
[0002]
[Prior art]
An engine in which a drive gear provided on a camshaft meshes with a driven gear provided on an auxiliary drive shaft connected to a vacuum pump and a hydraulic pump is known, for example, from Japanese Patent Application Laid-Open No. Hei 8-261001.
[0003]
[Problems to be solved by the invention]
The above-described conventional engine is an SOHC engine having a single camshaft. However, when an accessory drive structure similar to the above-described conventional engine is applied to an engine having a pair of camshafts, the engine has a pair of camshafts. It is desired to configure a structure for driving the accessory so that the engine can be made as compact as possible while avoiding interference with the engine.
[0004]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide an engine that can be made compact when driving an auxiliary machine with a camshaft.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a first camshaft having a power input portion at one end and a second camshaft having one end interlocked with and connected to the first camshaft are mutually connected. A driven gear rotatably supported by the cylinder head having an axis parallel to the cylinder head and meshing with a drive gear provided at one of the other ends of the first and second camshafts is provided on the engine body including the cylinder head. In the engine provided on the accessory drive shaft connected to the attached accessory, the axis of the accessory drive shaft is disposed between the camshafts on the cylinder head side with respect to a straight line connecting the axes of the first and second camshafts. It is characterized by being performed.
[0006]
According to the configuration of the first aspect of the present invention, the auxiliary drive shaft is brought close to one of the two camshafts without increasing the interval between the pair of camshafts, and the engine is driven in the direction along the cylinder axis. Compactness can be achieved.
[0007]
According to another aspect of the present invention, a first camshaft having a power input portion at one end and a second camshaft having one end interlocked and connected to the first camshaft are provided. An engine body including the cylinder head, the driven gear rotatably supported on the cylinder head having axes parallel to each other and meshing with a drive gear provided at one of the other ends of the first and second camshafts; In an engine provided on an accessory drive shaft connected to an accessory attached to the cylinder head, a cylinder head is provided at a position where a bearing portion supporting the accessory drive shaft partially overlaps the drive gear when viewed from a direction along a cylinder axis. And a notch formed in the bearing portion for avoiding interference with the drive gear.
[0008]
According to the configuration of the second aspect of the present invention, it is possible to prevent the position of the camshaft in the direction along the cylinder axis from being increased while providing the bearing for supporting the auxiliary drive shaft with the axis of the camshaft. , And can be arranged close to the drive gear in the direction along the direction, and can contribute to downsizing of the engine.
[0009]
In order to achieve the above object, the invention according to claim 3 is characterized in that a first camshaft having a power input portion at one end and a second camshaft having one end interlocked with and connected to the first camshaft are mutually connected. A driven gear rotatably supported by the cylinder head having an axis parallel to the cylinder head and meshing with a drive gear provided at one of the other ends of the first and second camshafts is provided on the engine body including the cylinder head. In the engine provided on the accessory drive shaft connected to the attached accessory, a bearing member disposed at a position partially overlapping the drive gear as viewed from a direction along the cylinder axis and supporting the accessory drive shaft, The bolts are fixed to the cylinder head with a plurality of bolts, and some of the bolts are arranged so as not to overlap with the drive gear when viewed from a direction along the cylinder axis, and the remaining bolts are A first imaginary plane that is disposed at a position overlapping with the drive gear when viewed from a direction along the cylinder axis, passes through the top surfaces of the some bolts, and is parallel to the axes of the two camshafts; A portion of the outer peripheral surface of the drive gear facing the remaining bolt is disposed between the first virtual plane and a second virtual plane parallel to the top surface.
[0010]
According to the configuration of the third aspect of the present invention, the accessory drive shaft can be made closer to one of the two camshafts without increasing the interval between the pair of camshafts, and the accessory drive shaft can be connected. The bearing member to be supported can be arranged close to the drive gear in the direction along the axis of the camshaft while avoiding the position of the camshaft in the direction along the cylinder axis, contributing to downsizing of the engine. Can be.
[0011]
According to a fourth aspect of the present invention, in addition to the configuration of the first aspect of the present invention, a helical gear that meshes with each other is provided at one end of the first and second camshafts. Thrust force generated on the camshaft of the two camshafts on which the drive gear is provided due to meshing of the helical gear, and thrust force generated on the camshaft provided with the drive gear by the meshing of the helical gear with the drive gear and the driven gear According to such a configuration, the durability of the helical gear provided at one end of the first and second camshafts and the gear for driving the auxiliary machine are characterized. Can be improved.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described based on an embodiment of the present invention shown in the attached drawings.
[0013]
1 to 8 show an embodiment of the present invention. FIG. 1 is a partial longitudinal sectional view of the engine, and is a sectional view taken along line 1-1 of FIG. 3, and FIG. FIG. 3 is an enlarged view taken along line 3-2 of FIG. 2, FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 1, and FIG. 6 is an enlarged sectional view taken along line 6-6 of FIG. 5, FIG. 7 is a sectional view taken along line 7-7 of FIG. 6, and FIG. 8 is a sectional view taken along line 8-8 of FIG.
[0014]
1 and 2, the engine is a compression ignition type DOHC type in-line four-cylinder engine, and a piston head (not shown) is provided between a cylinder head 11 and a cylinder block 12, which constitute a part of an engine body 10. Is formed for each of the first to fourth cylinders C1, C2, C3, and C4, and the intake valve ports 14A and 14B and the exhaust valve ports 15A and 15B that open to the respective combustion chambers 13 are cylinders. A pair of intake ports 17A, 17B and a pair of exhaust ports are provided on the cylinder head 11 for each of the cylinders C1 to C4 arranged in the direction along the arrangement direction 16 and can communicate with both the intake valve ports 14A, 14B. A pair of exhaust ports 18A, 18B that can communicate with 15A, 15B are provided in the cylinder head 11, and face the center of each combustion chamber 13. Unishi fuel injection valve (not shown) Te is attached to the cylinder head 11.
[0015]
The intake valves 20 that can open and close the respective intake valve ports 14A and 14B are slidably fitted to guide cylinders 21 provided on the cylinder head 11, and the upper ends of the respective intake valves 20 are connected to the cylinder head 11 and the cylinder. Projected from the guide cylinders 21 into valve operating chambers 25 formed between the head covers 24 connected to the heads 11 and provided between the cylinder heads 11 and the retainers 22 provided at the upper ends of the intake valves 20. The intake valves 20 are urged in the valve closing direction by the valve springs 23. Exhaust valves 26, which can open and close the respective exhaust valve ports 15A, 15B, are slidably fitted to guide cylinders 27 provided on the cylinder head 11, and the upper ends of the respective exhaust valves 26 ... Each of the exhaust valves 26 is biased in the valve closing direction by a retainer 28 provided at an upper end of each of the exhaust valves 26 and a valve spring 29 provided between the cylinder heads 11. Is done.
[0016]
First and second camshafts 31 and 32 having axes parallel to each other along the cylinder arrangement direction 16 are provided on the cylinder head 11 for each of the camshafts at positions spaced in the cylinder arrangement direction 16. Are rotatably supported by a plurality of first and second bearing portions 33A, 33, 34A, 34, respectively. The first bearing portions 33A, 33, and the second bearing portions 34A, 34 ... The lower cam holder 35 is fastened to the cylinder head 11, and a plurality of exhaust-side and intake-side upper cam holders 36, 37, ... fastened to the lower cam holder 35. The upper cam holders 36, 37,. Are fastened to the cylinder head 11 by a plurality of bolts 38.
[0017]
Referring also to FIG. 3, the lower cam holder 35 is disposed inside the pair of outer vertical frames 35 a and 35 b extending along the cylinder arrangement direction 16 and along the cylinder arrangement direction 16. Are formed in an integrated frame structure integrally having a pair of inner vertical frames 35c and 35d extending therefrom, and between the outer vertical frame 35a and the inner vertical frame 35c on the side where the exhaust valves 26 are arranged. , Which receive the lower half of the first camshaft 31, are provided so as to sandwich each of the cylinders C1 to C4 from both sides, and cooperate with the lower bearings 35d. , 33 are fastened to the lower cam holder 35. Also, between the outer vertical frame 35b and the inner vertical frame 35d on the side where the intake valves 20 are arranged, five lower bearing portions 35e for receiving the lower half of the second camshaft 32 are provided for the respective cylinders C1 to C4. Are provided from both sides, and the upper cam holders 37 on the intake side are fastened to the lower cam holder 35 in cooperation with the lower bearings 35e so as to form the second bearings 34A, 34.
[0018]
Between the plurality of first bearing portions 33A, 33 ..., the outer vertical frame 35a and the inner vertical frame 35c on the side on which the exhaust valves 26 are arranged are connected by partition walls 35f ... Between the bearing portions 34A, 34, the outer vertical frame 35b and the inner vertical frame 35d on the side where the intake valves 20 are arranged are connected by partition walls 35g.
[0019]
Between the first bearing portions 33A, 33 ... and the partition walls 35f on the side where the exhaust valves 26 are arranged, a swing in a plane orthogonal to the axis of the first camshaft 31 is enabled, and one end is hydraulically driven. Exhaust-side rocker arms 40 pivotally supported on the cylinder head 11 via tappets 42 are arranged, and the other end of each of the exhaust-side rocker arms 40 contacts the upper end of each of the exhaust valves 26. 26 and are linked. Between the second bearing portions 34A, 34 and the partition walls 35g on the side where the intake valves 20 are arranged, one end thereof is made rotatable in a plane orthogonal to the axis of the second camshaft 32. An intake-side rocker arm 41 pivotally supported by the cylinder head 11 via a hydraulic tappet 43 is disposed, and the other end of each intake-side rocker arm 41... Interlocked with and connected to the valves 20.
[0020]
4, the projections 46 projecting toward the intake side rocker arms 41 are formed on the second bearings 34A, 34 and the partition walls 35g on the side where the intake valves 20 are arranged. Each of the projections 46 is provided between the projections 46 to prevent the intake side rocker arms 41 from falling down. The first bearing portions 33A, 33 and the partition walls 35f on the side where the exhaust valves 26 are arranged are also provided with projections 46 projecting toward the exhaust side rocker arms 40, respectively. The exhaust-side rocker arms 40 are prevented from falling down by being sandwiched between the protrusions 46.
[0021]
A roller 48 is rotatably supported at an intermediate portion of each of the exhaust side rocker arms 40 via a support shaft 47 having an axis parallel to the first camshaft 31. An intermediate portion of each of the intake side rocker arms 41 has A roller 50 is rotatably supported via a support shaft 49 having an axis parallel to the second camshaft 32. The rollers 48, 50 are in rolling contact with valve cams 31a, 32a provided on the first and second camshafts 31, 32, respectively.
[0022]
A portion of the plurality of second bearing portions 34A, 34... Protruding from one end side second bearing portion 34A disposed at one end side along the cylinder arrangement direction 16 is provided on the second camshaft 32 as a first driven gear, which is a helical gear. Are provided on the first camshaft 31 at a portion protruding from one end side first bearing portion 33A disposed at one end side along the cylinder arrangement direction 16 among the plurality of first bearing portions 33A, 33. A first driving gear 51 having a cylindrical projecting portion 58a which is a helical gear meshing with the first driven gear 52 and which projects toward the first bearing portion 33A on one end side from the meshing portion with the first driven gear 52; A sprocket 53 as a power input portion, which is disposed on the opposite side of the first bearing portion 33A with respect to the drive gear 51 and around which the cam chain 54 is wound, is fixed.
[0023]
One ends of the first and second camshafts 31 and 32 are arranged in a chain chamber 56 formed between the engine body 10 including the cylinder head 11 and a chain case 55 connected to the engine body 10. A cam chain 54 running in a chain chamber 56 is wound around a sprocket 53 so as to transmit power from a crankshaft (not shown).
[0024]
The first drive gear 51 is formed by combining first and second gears 58 and 59 in which friction rubber 57 is interposed therebetween in a wobble structure. The first gear 58 integrally has cylindrical projections 58 a and 58 b coaxially surrounding the first camshaft 31 on both sides in the axial direction, and these projections 58 a and 58 b correspond to the first camshaft 31. A bolt 60 that is sandwiched between the annular step portion 31 a provided on the first cam shaft 31 and the sprocket 53 and is engaged with the sprocket 53 is coaxially screwed to the first camshaft 31. Moreover, a key 61 is inserted between the inner periphery of the first gear 58 and the sprocket 53 and the outer periphery of the first camshaft 31, and the first drive gear 51 and the sprocket 53 are moved by the bolt 60 and the key 61 to the first camshaft. Fixed to 31.
[0025]
By the way, the first gear 58 is provided with a protruding portion 58a that protrudes from the meshing portion between the first drive gear 51 and the first driven gear 52 toward the first bearing portion 33A on one end side. An oil passage 62 for guiding the lubricating oil to a meshing portion with the first driven gear 52 through a space between the gears 58 and 59 is formed in the first camshaft 31 by avoiding a screwing portion of the bolt 60 to the first camshaft 31. In the first camshaft 31, a portion corresponding to the one end side first bearing portion 33A connects the oil supply passage 63 provided in the lower cam holder 35 and the oil passage 62 in the first camshaft 31. The oil passage 64 is formed coaxially.
[0026]
As clearly shown in FIG. 3, the one end side first bearing portion 33A is arranged to be offset from the one end side second bearing portion 34A on the side away from the first drive gear 51.
[0027]
In addition, of the two exhaust valve ports 15A and 15B corresponding to the first camshaft 31, the exhaust valve port 15A near the one end side first bearing portion 33A is the one of the two intake valve ports 14A and 14B corresponding to the second camshaft 32. The first drive gear 51 is offset from the intake valve port 14A of the one end second bearing portion 34A.
[0028]
Incidentally, of the pair of intake valve ports 14A, 14B provided on the cylinder head 11 on the side corresponding to the second camshaft 32, the pair of intake valve ports 14A, 14B is connected to the intake valve port 14A arranged on the side closer to the one end second bearing portion 34A. An intake port 17 </ b> A provided in the cylinder head 11 is formed in a shape that causes a swirl in the combustion chamber 13.
[0029]
The distance between the exhaust side rocker arm 40 adjacent to the one end side first bearing portion 33A and the one end side first bearing portion 33A is the intake side rocker arm 41 and one end side second bearing portion 34A adjacent to the one end side second bearing portion 34A. It is set narrower than the interval between them.
[0030]
Further, a side surface on the first drive gear 51 side of the one end side first bearing portion 33A corresponds to the one end side first bearing portion 33A of a plurality of bolts 38 for fastening the lower cam holder 35 and the upper cam holder 36 to the cylinder head 11. The first camshaft 31 is disposed axially inward of the pair of bosses 65, 65 provided on the one end side first bearing portion 33 </ b> A in order to insert the bolts 38 of the first camshaft 31.
[0031]
5 to 8, a second drive gear 68 as a helical gear is provided at the other end of the first camshaft 31, and a second driven gear 69 as a helical gear is connected to a cylinder in the engine body 10. An accessory drive shaft 71 connected to a high-pressure fuel pump 70 as an accessory attached to the head 11 is provided. The second drive gear 68 is formed by combining third and fourth gears 73 and 74 in which friction rubber 72 is interposed therebetween in a wobble structure.
[0032]
The accessory drive shaft 71 is rotatably supported by a bearing portion 76 formed by fastening a bearing member 75 separate from the cylinder head 11 to the cylinder head 11 with three bolts 77, 78, 79,. The high pressure fuel pump 70 is connected to a rotating shaft 70 a of the high pressure fuel pump 70 via an Oldham joint 80.
[0033]
By the way, the axis of the accessory drive shaft 71 is disposed closer to the cylinder head 11 than the straight line L connecting the axes of the first and second camshafts 31 and 32, and the bearing portion 76 extends in the direction along the cylinder axis. A notch 75 a is provided in the cylinder head 11 at a position where it partially overlaps the second drive gear 68 as viewed from above, and a notch 75 a for avoiding interference with the second drive gear 68 is formed in the bearing member 75 of the bearing portion 76.
[0034]
Of the three bolts 77, 78, 79 for fastening the bearing member 75 constituting the bearing portion 76 to the cylinder head 11, two bolts 77, 78 are the second drive gear 68 when viewed from the direction along the cylinder axis. The remaining bolts 79 are disposed on both sides of the accessory drive shaft 71 at positions that do not overlap with each other, and the remaining bolts 79 are viewed from the direction along the cylinder axis to increase the fastening rigidity of the bearing member 75 to the cylinder head 11. The bearing member 65 is arranged to be fastened to the cylinder head 11 at a position where the bearing member 65 partially overlaps the second drive gear 68.
[0035]
Moreover, a first imaginary plane P1 which is parallel to the axes of the first and second camshafts 31, 32 through the top surfaces of the two bolts 77, 78 which are a part of the bolts 77 to 79, A portion of the outer peripheral surface of the second drive gear 68 facing the remaining bolt 79 is disposed between the first virtual plane P1 and a second virtual plane P2 parallel to the first virtual plane P1 through the top surface of the remaining bolt 79. The notch 75a is formed in the bearing member 75 of the bearing portion 76 so as to avoid interference of the remaining bolt 79 with the second drive gear 68.
[0036]
The first drive gear 51 and the first driven gear 52 meshing with each other at one end of the first and second camshafts 31 and 32 are helical gears. A second drive gear 68 provided at the other end of the second drive gear 68 and a second driven gear 69 provided on the accessory drive shaft 71 so as to mesh with the second drive gear 68 are also helical gears. The thrust force generated on the first camshaft 31 as shown by the arrow 81 in FIG. 5 due to the meshing of the gears 51 and 52, and the meshing of the second drive gear 68 and the second driven gear 69 as shown by the arrow 82 in FIG. The thrust force generated in the first camshaft 31 is set so as to be opposite to each other.
[0037]
6 and 7, the cylinder head 11 is provided with a concave portion 83 for accommodating a part of the second driven gear 69, whereby the first camshaft 31 in the direction along the cylinder axis is provided. Height can be reduced as much as possible, which contributes to downsizing of the engine. In addition, since the second driven gear 69 scoops up the oil accumulated in the concave portion 83, the meshing portion between the second driving gear 68 and the second driven gear 69 can be lubricated.
[0038]
Next, the operation of this embodiment will be described. Of the plurality of second bearing portions 34A, 34... Provided on the cylinder head 11 for each of the camshafts 31, 32 at positions spaced in the cylinder arrangement direction 16. A first driven gear 52 is provided on the second camshaft 32 at a portion protruding from one end side second bearing portion 34 </ b> A disposed at one end side along the cylinder arrangement direction 16, and is spaced in the cylinder arrangement direction 16. .. Protruded from one end side first bearing portion 33A arranged at one end side along the cylinder arrangement direction 16 among the plurality of first bearing portions 33A, 33. The first camshaft 31 has a cylindrical projecting portion 58a that meshes with the first driven gear 52 and projects toward the first bearing portion 33A on one end side from the meshing portion with the driven gear 52. First and driving gear 51 is fixed to one end first bearing portion 33A are arranged to be offset to the side away from the first drive gear 51 than the end side second bearing section 34A.
[0039]
Therefore, the first drive gear 51 and the first driven gear 52 can be further moved to the cylinder head by arranging the protruding portion 58a in a space created by the offset arrangement of the one end side first bearing portion 33A with respect to the one end side second bearing portion 34A. Therefore, the engine can be made compact.
[0040]
Further, a sprocket 53 for inputting power from a crankshaft is fixed to the first camshaft 31 on the opposite side of the first drive gear 51 from the one end side first bearing portion 33A, and the sprocket 53 is further connected to the cylinder head. The engine can be further compacted in the direction along the axis of both camshafts 31 and 32 by approaching to the 11 side. The first driven gear 52 provided on the second camshaft 32 on the side of the intake valves 20... To which power from the crankshaft is not directly input is brought close to the one end side second bearing portion 34 </ b> A, so that the second camshaft 32 Torque fluctuation can be suppressed.
[0041]
Further, a pair of intake valve ports 14A, 14B and exhaust valve ports 15A, 15B opening to the combustion chamber 13 are arranged in the direction along the axis of the camshafts 31, 32, one pair for each cylinder C1 to C4. Of the two exhaust valve ports 15A, 15B corresponding to the first camshaft 31, the exhaust valve port 15A closer to the first bearing portion 33A on one end side has the two intake valve ports 14A, 14B corresponding to the second camshaft 32. Of these, the first drive gear 51 is offset from the intake valve port 14A near the one end side second bearing portion 34A, so that the one end side first bearing portion 33A with respect to the one end side second bearing portion 34A. The engine is further compacted in the axial direction of the camshafts 31 and 32 by offsetting the intake valve port 14A and the exhaust valve port 15A with each other in accordance with the offset. It can be.
[0042]
In addition, a pair of exhaust valve ports 15A, 15B are provided on the cylinder head 11 on the side corresponding to the first camshaft 31, and a pair of intake valve ports 14A, 15A, 15A, 15B provided on the cylinder head 11 on the side corresponding to the second camshaft 32. Of the 14B, an intake port 17A provided in the cylinder head 11 in connection with the intake valve port 14A disposed on the side closer to the one end side second bearing portion 34A is formed in a shape that causes swirl in the combustion chamber 13. In addition, the swirl can be effectively formed in the combustion chamber 13 in combination with the above-described offset between the intake valve port 14A and the exhaust valve port 15A to improve the combustion efficiency.
[0043]
In addition, a plurality of exhaust-side and intake-side rocker arms 40, 41,..., Which can swing in a plane perpendicular to the axis of the first and second camshafts 31, 32 and whose one end is pivotally supported by the cylinder head 11, are provided. The ends are interlocked and connected to the exhaust valve 26 and the intake valve 20, respectively, and the first and second bearing portions 33A, 33; 34A, 34 are respectively connected to the exhaust-side and intake-side rocker arms 40, 41,. Are provided on both sides of the lower cam holder 35 and are provided with projections 46 for preventing the rocker arms 40... 41 from falling down. .., 37... On the intake side, the exhaust side rocker arm 40 adjacent to the one end side first bearing portion 33A, and the one end side first bearing portion. Spacing between 3A is set smaller than the interval between the intake-side rocker arm 41 and the one end side second bearing section 34A adjacent to one side second bearing portion 34A. For this reason, by bringing the one end side first bearing portion 33A close to the exhaust side rocker arm 40, the amount of protrusion of the projection 46 provided on the lower cam holder 35 at a portion corresponding to the one end side first bearing portion 33A is reduced, and the lower cam holder 35 , And thus the entire engine.
[0044]
Further, a side surface of the one end side first bearing portion 33A on the side of the first drive gear 51 is provided on one end side first bearing of a plurality of bolts 38 for fastening the lower cam holder 35 and the exhaust side upper cam holder 36 to the cylinder head 11. The first camshaft 31 is disposed axially inward of the first camshaft 31 with respect to the pair of bosses 65 provided on the one end side first bearing portion 33A so as to insert the bolts 38 corresponding to the portion 33A. The offset amount of the first side bearing portion 33A with respect to the one end side second bearing portion 34A can be made relatively large, and the engine can be made more compact.
[0045]
Further, a second driven gear 69 meshing with a second drive gear 68 provided at the other end of the first camshaft 31 has an auxiliary drive shaft connected to a high-pressure fuel pump 70 mounted on the cylinder head 11 of the engine body 10. The auxiliary drive shaft 71 is disposed between the camshafts 31 and 32 on the cylinder head 11 side of a straight line L connecting the axes of the first and second camshafts 31 and 32.
[0046]
Therefore, the accessory drive shaft 70 can be brought close to the first camshaft 31 without increasing the space between the first and second camshafts 31 and 32, and the engine can be made compact in the direction along the cylinder axis. .
[0047]
Further, a bearing portion 76 for supporting the accessory drive shaft 71 is provided on the cylinder head 11 at a position where the bearing portion 76 partially overlaps the second drive gear 68 when viewed from the direction along the cylinder axis. Since the notch 75a to be avoided is formed in the bearing portion 76, the bearing portion 76 that supports the accessory drive shaft 71 can be prevented from being raised in position of the camshafts 31 and 32 in the direction along the cylinder axis. , Can be arranged close to the second drive gear 68 in the direction along the axis of the first camshaft 31, which can also contribute to downsizing of the engine.
[0048]
The bearing portion 76 is formed by fastening a bearing member 75 that rotatably supports the accessory drive shaft 71 to the cylinder head 11 with three bolts 77, 78, 79. Two bolts 77 and 78 out of 77 to 79 are arranged on both sides of the accessory drive shaft 71 at positions not overlapping with the second drive gear 68 when viewed from the direction along the cylinder axis, while the remaining bolts 77 and 78 The bolt 79 fastens the bearing member 65 to the cylinder head 11 at a position where the bolt 79 partially overlaps the second drive gear 68 when viewed from the direction along the cylinder axis in order to increase the fastening rigidity of the bearing member 75 to the cylinder head 11. It is arranged to be.
[0049]
Moreover, a first imaginary plane P1 which is parallel to the axes of the first and second camshafts 31, 32 through the top surfaces of the two bolts 77, 78 which are a part of the bolts 77 to 79, A portion of the outer peripheral surface of the second drive gear 68 facing the remaining bolt 79 is disposed between the first virtual plane P1 and a second virtual plane P2 parallel to the first virtual plane P1 through the top surface of the remaining bolt 79. ing.
[0050]
Therefore, the auxiliary drive shaft 71 can be brought closer to the first camshaft 31, which is one of the camshafts 31, 32, without increasing the interval between the first and second camshafts 31, 32, and the bearing member can be provided. 75 can be arranged close to the second drive gear 68 in a direction along the axis of the camshafts 31 and 32 while avoiding an increase in the position of the camshaft in the direction along the cylinder axis. This can contribute to downsizing.
[0051]
Further, the first drive gear 51 and the first driven gear 52 provided at one end of the first and second camshafts 31 and 32 and meshing with each other are helical gears, and the first drive gear 51 and the first driven gear 52 Since the thrust force generated on the first camshaft 31 by the engagement and the thrust force generated on the first camshaft 31 by the engagement of the second drive gear 68 and the second driven gear 69, which are helical gears, are set to be opposite to each other. , A first driving gear 51 and a first driven gear 52 provided at one end of the first and second camshafts 31 and 32, and a second driving gear 68 and a second driven gear 69 for driving the high-pressure fuel pump 70. Can be improved in durability.
[0052]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.
[0053]
For example, in the above-described embodiment, the high-pressure fuel pump 70, which is an accessory, is attached to the cylinder head 11, but the accessory may be attached to a portion other than the cylinder head 11 of the engine body 10, for example, the cylinder block 12. In this case, the axis of the accessory drive shaft 71 may be disposed between the camshafts 31 and 32 on the cylinder head 11 side with respect to the straight line L connecting the axes of the camshafts 31 and 32.
[0054]
Further, the present invention can be applied to an engine for a marine propulsion device such as an outboard motor having a vertical axis of a crankshaft.
[0055]
【The invention's effect】
As described above, according to the first aspect of the present invention, the auxiliary drive shaft is brought close to one of the two camshafts without increasing the interval between the pair of camshafts, and the engine is driven in the direction along the cylinder axis. Compactness can be achieved.
[0056]
According to the second aspect of the present invention, the bearing for supporting the accessory drive shaft is moved in the direction along the axis of the camshaft while avoiding the position of the camshaft in the direction along the cylinder axis becoming high. It can be arranged close to the drive gear, which can contribute to downsizing of the engine.
[0057]
According to the third aspect of the present invention, the auxiliary drive shaft can be brought close to one of the two cam shafts without increasing the interval between the pair of cam shafts, and the bearing member for supporting the auxiliary drive shaft can be provided. The position of the camshaft in the direction along the cylinder axis can be prevented from being high, and the camshaft can be arranged close to the drive gear in the direction along the axis of the camshaft, thereby contributing to downsizing of the engine.
[0058]
Further, according to the invention described in claim 4, the durability of the helical gear provided at one end of the first and second camshafts and the gear for driving the auxiliary machine can be improved.
[Brief description of the drawings]
1 is a partial longitudinal sectional view of an engine, and is a sectional view taken along line 1-1 in FIG. 3;
FIG. 2 is a view taken along line 2-2 of FIG. 1 with a head cover removed.
FIG. 3 is an enlarged view of a portion indicated by an arrow 3 in FIG. 2;
FIG. 4 is a sectional view taken along line 4-4 of FIG. 1;
FIG. 5 is an enlarged view of a portion indicated by an arrow 5 in FIG. 2;
FIG. 6 is an enlarged sectional view taken along line 6-6 of FIG. 5;
FIG. 7 is a sectional view taken along line 7-7 of FIG. 6;
8 is a sectional view taken along line 8-8 of FIG. 7;
[Explanation of symbols]
10 ・ ・ ・ Engine body
11 ... Cylinder head
31 ... first camshaft
32 ... second camshaft
53 ・ ・ ・ Sprocket as power input unit
68 ... drive gear
69 ... driven gear
70 High-pressure fuel pump as auxiliary equipment
71 ・ ・ ・ Auxiliary drive shaft
75 ・ ・ ・ Bearing member
75a ... notch
76 ・ ・ ・ Bearing part
77, 78, 79 ... bolt
L: straight line
P1 1st virtual plane
P2: Second virtual plane

Claims (4)

A first camshaft (31) having a power input portion (53) at one end and a second camshaft (32) having one end interlocked and connected to the first camshaft (31) are mutually parallel axes. The driven gear (69) rotatably supported by the cylinder head (11) and meshing with a drive gear (68) provided at one other end of the first and second camshafts (31, 32). ) Are provided on an accessory drive shaft (71) connected to an accessory (70) attached to an engine body (10) including a cylinder head (11), in which the first and second camshafts (31, 32) are provided. The engine is characterized in that the axis of the accessory drive shaft (71) is arranged between the two camshafts (31, 32) on the cylinder head (11) side of the straight line (L) connecting the axes of (1) and (2). A first camshaft (31) having a power input portion (53) at one end and a second camshaft (32) having one end interlocked and connected to the first camshaft (31) are mutually parallel axes. The driven gear (69) rotatably supported by the cylinder head (11) and meshing with a drive gear (68) provided at one other end of the first and second camshafts (31, 32). ) Supports an accessory drive shaft (71) in an engine provided on an accessory drive shaft (71) connected to an accessory (70) attached to an engine body (10) including a cylinder head (11). A notch for preventing interference with the drive gear (68) is provided on the cylinder head (11) at a position where the bearing (76) partially overlaps the drive gear (68) when viewed from a direction along the cylinder axis. (75a) is the bearing Engine, characterized in that formed in (76). A first camshaft (31) having a power input portion (53) at one end and a second camshaft (32) having one end interlocked and connected to the first camshaft (31) are mutually parallel axes. The driven gear (69) rotatably supported by the cylinder head (11) and meshing with a drive gear (68) provided at one other end of the first and second camshafts (31, 32). ) Is provided on an accessory drive shaft (71) connected to an accessory (70) attached to an engine body (10) including a cylinder head (11), wherein the drive gear is viewed from a direction along a cylinder axis. A bearing member (75) arranged at a position partially overlapping with (68) and supporting the accessory drive shaft (71) is fixed to the cylinder head (11) with a plurality of bolts (77, 78, 79). And said each bolt 77 to 79), some of the bolts (77, 78) are arranged so as not to overlap with the drive gear (68) when viewed from the direction along the cylinder axis, and the remaining bolts (79) are attached to the cylinder axis. A first position which is arranged at a position overlapping with the drive gear (68) when viewed from the direction along the axis and which is parallel to the axes of the two camshafts (31, 32) through the top surfaces of the bolts (77, 78). Between the virtual plane (P1) and a second virtual plane (P2) parallel to the first virtual plane (P1) through the top surface of the remaining bolt (79); An engine, wherein a portion of the outer peripheral surface facing the remaining bolt (79) is arranged. Helical gears (51, 52) meshing with each other are provided at one end of the first and second camshafts (31, 32). The driving gear (68) is provided by a thrust force generated on a camshaft (31) provided with the driving gear (68) and the engagement of the driving gear (68) and the driven gear (69), which are helical gears. The engine according to any one of claims 1 to 3, wherein the thrust force generated on the camshaft (31) is set to be opposite to each other.

Images