JP2004100551A - Air pump drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the number of components and a size of a whole engine, facilitate mounting to vehicle and the like, and increase flexibility in setting a change gear ratio of an air pump, in an air pump drive device which drive the air pump with an engine. <P>SOLUTION: The engine is constituted to be 4-cycle having a camshaft 41 constituting a part of a valve system 38 and arranged to a cylinder block 13. A pump case 63 of the air pump 61 to which a power is transmitted from the camshaft 41 is integrally formed to the cylinder block 13. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement in an air pump driving device that drives an air pump with an engine.
[0002]
[Prior art]
Conventionally, such an air pump driving device is already known, for example, from Patent Document 1, Patent Document 2, Patent Document 3, and the like.
[0003]
[Patent Document 1]
JP-A-11-44216
[Patent Document 2]
Japanese Patent No. 2820782
[Patent Document 3]
JP 2000-170501 A
[0004]
[Problems to be solved by the invention]
In the device disclosed in Patent Document 1, a double-acting piston type air pump having a pump case separate from a cylinder head is configured to be driven by a camshaft on the cylinder head, and has a volume and Since the air pump is attached to the cylinder head having a relatively large mass, the position of the center of gravity of the engine may be shifted to the cylinder head side, and it may be difficult to mount the engine on a vehicle or the like.
[0005]
Further, in the one disclosed in Patent Document 2, the pump cover of the air pump which is separate from the clutch cover is attached to the clutch cover coupled to the crankcase, which not only increases the number of parts but also increases the number of parts. This may lead to an increase in the size of the entire engine. In addition, since power is transmitted from the crankshaft of the engine to the air pump via a special gear train, not only the number of parts is increased, but also the size of the engine may be increased.
[0006]
Further, in the structure disclosed in Patent Document 3, the pump case of the air pump is formed integrally with the cylinder block so that the air pump is directly driven by the crankshaft, and is arranged in a direction along the axis of the crankshaft. The engine becomes large, and the gear ratio of the air pump cannot be freely set.
[0007]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and facilitates mounting on a vehicle and the like while reducing the number of parts and reducing the size of an entire engine, and furthermore, has a degree of freedom in setting a gear ratio of an air pump. It is an object of the present invention to provide an air pump drive device with increased power.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is an air pump driving device for driving an air pump with an engine, wherein the engine constitutes a part of a valve train and is arranged in a cylinder block. And a pump case of the air pump to which power from the camshaft is transmitted is formed integrally with the cylinder block.
[0009]
According to the structure of the first aspect of the present invention, since the pump case is formed integrally with the cylinder block having a smaller outer shape than the cylinder head and the crankcase which cooperate with the engine body, The overall engine size can be reduced while reducing the number of points, and the camshaft that drives the air pump is also located on the cylinder block, so the power transmission means that transmits power from the camshaft to the air pump is compact. And the degree of freedom in setting the gear ratio of the air pump is increased.
[0010]
According to a second aspect of the present invention, in addition to the configuration of the first aspect, a power transmission unit including an endless power transmission band is provided between the pump drive shaft connected to the air pump and the camshaft. According to this configuration, regardless of the distance between the camshaft and the pump drive shaft, the cylinder block can be prevented from increasing in size and the number of parts can be reduced.
[0011]
According to a third aspect of the present invention, in addition to the configuration of the second aspect of the present invention, the pump drive shaft is located at a position which is plane-symmetric with respect to a plane orthogonal to the pump drive shaft including the cylinder axis of the engine. The air pump and the auxiliary device connected to both ends are arranged, and according to this configuration, the auxiliary device is driven by a pump drive shaft connected to the air pump, so that the number of parts is reduced and the weight is reduced. The cost can be reduced by simplifying the processing and assembly. In addition, the protrusion of the accessory from the cylinder block can be suppressed, and an increase in the size of the entire cylinder block can be avoided.
[0012]
According to a fourth aspect of the present invention, in addition to the configuration of the third aspect of the invention, the engine is a water-cooled type, and the auxiliary machine is a water pump. By arranging the water pump near the power cylinder block and the cylinder head, the water piping can be shortened, the piping can be prevented from becoming complicated, and the pressure loss in the piping can be reduced.
[0013]
According to a fifth aspect of the present invention, in addition to the configuration of the first aspect, the air pump is a reciprocating type that reciprocates a piston in a direction parallel to a cylinder axis of the engine. And a pump drive shaft to which power from the camshaft is transmitted is connected to the piston via a Scotch and yoke type crank. According to such a configuration, a relatively high air pressure can be obtained. The size of the engine can be reduced by making the operating axis of the air pump parallel to the cylinder axis of the engine and eliminating the need for connecting rods by using a scotch-yoke type crank.
[0014]
According to a sixth aspect of the present invention, in addition to the configuration of the fifth aspect of the invention, the pump case of the air pump has a bottomed cylindrical shape having an axis parallel to the cylinder axis of the engine and opening the cylinder head side. A lid member formed integrally with the cylinder block and hermetically closing the opening on the cylinder head side of the pump case is coupled to the pump case on the same plane as the coupling surface of the cylinder block and the cylinder head. According to this configuration, it is possible to reduce the number of processing steps of the cylinder block.
[0015]
According to a seventh aspect of the present invention, in addition to the configuration of the first aspect, an injector for directly injecting fuel into a combustion chamber together with compressed air supplied from the air pump is provided. According to such a configuration, the air pump is not provided on the cylinder head, so that the injector and its piping are connected to the cylinder head while increasing the degree of freedom in layout and miniaturizing the engine. Can be arranged. In particular, when the pump chamber of the air pump is arranged on the cylinder head side, the distance between the pump chamber and the injector is made relatively short, and the pipe structure connecting the air pump and the injector is prevented from becoming complicated. Pressure loss can be reduced.
[0016]
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.
[0017]
1 to 8 show an embodiment of the present invention. FIG. 1 is a partial longitudinal side view of an engine, FIG. 2 is a view taken along line 2-2 of FIG. 1 with a head cover removed, 3 is a sectional view taken along line 3-3 of FIG. 2, FIG. 4 is a sectional view taken along line 4-4 of FIG. 3, FIG. 5 is a sectional view taken along line 5-5 of FIG. FIG. 7 is a sectional view taken along line 7-7 of FIG. 5, and FIG. 8 is a longitudinal sectional side view of the engine taken along line 8-8 of FIG.
[0018]
First, referring to FIG. 1, an engine body 11 of an overhead valve type four-cycle water-cooled single-cylinder engine includes a crankcase 12, a cylinder block 13 coupled to the crankcase 12, and an opposite side to the crankcase 12. And a head cover 15 connected to the cylinder head 14 on the side opposite to the cylinder block 13, and a motorcycle with the cylinder head 14 side slightly raised forward. Mounted on vehicles.
[0019]
Referring to FIGS. 2 to 4 together, a piston 17 slidably fitted to a cylinder bore 16 provided in a cylinder block 13 is a crankshaft 10 (FIG. 1) rotatably supported by a crankcase 12. ) Via a connecting rod 18 and a crank pin (not shown). A combustion chamber 19 facing the top of the piston 17 is formed between the cylinder block 13 and the cylinder head 14.
[0020]
The cylinder head 14 has first and second intake valve ports 20, 21 opening to the ceiling surface of the combustion chamber 19, and an opening at the upper side surface of the cylinder head 14 connected to the intake valve ports 20, 21. And a single exhaust valve port 22 opening to the ceiling surface of the combustion chamber 19, and an exhaust port 24 opening to the lower side surface of the cylinder head 14 in connection with the exhaust valve port 22. An injector 25 for directly injecting fuel into the combustion chamber 19 together with the compressed air is disposed so as to be disposed on the axis of the cylinder bore 16, that is, on the cylinder axis C.
[0021]
A first intake valve port 20 and an exhaust valve port 22 are disposed on the cylinder axis C, that is, on both sides of the injector 25 on a projection view on a plane orthogonal to the cylinder axis C, and the first intake valve port 20 and the exhaust valve port are provided. The second intake valve port 21 is disposed on the cylinder axis C, that is, on one side of the injector 25 on another straight line L2 that is substantially orthogonal to the straight line L1 connecting the nozzles 22. A spark plug 26 is attached to the cylinder head 14 so as to face the combustion chamber 19 at a position avoiding the first intake valve port 20, the second intake valve port 21, and the exhaust valve port 22.
[0022]
The cylinder head 14 is provided with first and second intake valves 27 and 28 capable of opening and closing the first and second intake valve ports 20 and 21, respectively, so as to be capable of opening and closing, and opening and closing the exhaust valve port 22. A possible exhaust valve 29 is arranged for opening and closing operation. The first and second intake valves 27 and 28 are respectively slidably fitted to guide cylinders 30 fixed to the cylinder head 14, and are mounted on upper end portions of both intake valves 27 and 28 protruding from the guide cylinders 30. A valve spring 32 is provided between the fixed retainer 31 and the cylinder head 14, respectively, and both intake valves 27 and 28 are urged in a valve closing direction by a spring force exerted by the valve springs 32. The exhaust valve 29 is slidably fitted to a guide cylinder 33 fixed to the cylinder head 14, and a valve spring is provided between the cylinder head 14 and a retainer 34 fixed to an upper end of the exhaust valve 29 protruding from the guide cylinder 33. The exhaust valve 29 is urged in the valve closing direction by the spring force exerted by the valve spring 35.
[0023]
With further reference to FIGS. 5 to 7, the first and second intake valves 27 and 28 and the exhaust valve 29 are driven to be opened and closed by a valve operating device 38. A camshaft 41 that rotates having intake-side and exhaust-side cams 39, 40, an intake-side first rocker arm 42 that swings by following the intake-side cam 39, and swings by following the exhaust-side cam 40. An exhaust-side first rocker arm 43 that moves, an intake-side second rocker arm 44 having a pair of pressing arms 44a and 44b that contact the first and second intake valves 27 and 28, and a pressing arm that contacts the exhaust valve 29. A second rocker arm 45 on the exhaust side having a portion 45a, and a swinging motion of the first rocker arm on the intake side transmitted to the second rocker arm on the intake side between the first and second rocker arms on the intake side. And an exhaust-side push rod provided between the exhaust-side first and second rocker arms 43 and 45 so as to transmit the swinging motion of the intake-side push rod 46 and the exhaust-side first rocker arm 43 to the exhaust-side second rocker arm 45. 47.
[0024]
Between the cylinder head 14 and the head cover 15, a valve operating chamber for accommodating and arranging the intake-side and exhaust-side second rocker arms 44 and 45 and the intake-side and exhaust-side push rods 46 and 47 of the valve operating device 38. An oil ejection hole 36 is provided in the head cover 15 in order to lubricate a portion of the valve train 38 housed in the valve train chamber 48.
[0025]
In the crankcase 12, the cylinder block 13 and the cylinder head 14 of the engine body 11, oil lubricating the portion of the valve train 38 housed in the valve train 48 is formed in the lower part of the crankcase 12. An oil return passage 49 for returning to the pan 12a (see FIG. 1) is provided so as to extend parallel to the cylinder axis C on the side of the cylinder bore 16.
[0026]
The camshaft 41 of the valve train 38 is arranged in the cylinder block 13 so as to be accommodated in the oil return passage 49 while avoiding the valve train 48 between the cylinder head 14 and the head cover 15. 13 and a cover 50 which is fastened to the cylinder block 13 so as to form an outer surface of the oil return passage 49, both ends of a camshaft 41 having an axis parallel to the crankshaft via ball bearings 51, 51. Supported rotatably.
[0027]
In addition, the camshaft 41 has an oil supply passage 37 for supplying lubricating oil to sliding portions between the intake-side and exhaust-side cams 39 and 40 and the intake-side first rocker arm 42 and the exhaust-side first rocker arm 43. Is provided.
[0028]
In the oil return passage 49, a first driven sprocket 52, a first driving sprocket 60 (see FIG. 1), and an endless cam chain 53 are provided to transmit the power from the crankshaft 10 at a reduced speed of １ ／. The first driven sprocket 52 is housed therein and is relatively non-rotatably coupled to the camshaft 41, the first driving sprocket 60 is relatively non-rotatably coupled to the crankshaft 10, and the cam chain 53 is connected to the first driving sprocket 60 and the first driving sprocket 60. It is wound around one driven sprocket 52.
[0029]
The intake-side and exhaust-side first rocker arms 42, 43 have rollers 54, 55 that come into rolling contact with the intake-side and exhaust-side cams 39, 40 from the cylinder head 14 side, respectively, and have axes parallel to the camshaft 41. And is swingably supported by intake side and exhaust side first rocker shafts 56 and 57 provided between the cylinder block 13 and the cover 50. On the intake side and exhaust side first rocker arms 42, 43, bowl-shaped pressing portions 42a, 43a located on the opposite side to the rollers 54, 55 are provided integrally with each other so as to open to the cylinder head 14 side. .
[0030]
On the other hand, in the cylinder head 14 in the valve operating chamber 48, intake-side and exhaust-side second rocker shafts 58 and 59 having axes parallel to the camshaft 41 are arranged on both sides of the injector 25. The intake-side second rocker arm 42, which is supported and has a pair of forked bifurcated pressing arms 42a and 42b, is swingably supported by the intake-side rocker shaft 58, and the exhaust-side second rocker arm 43 is connected to the exhaust-side rocker. It is swingably supported by a shaft 59.
[0031]
In addition, the suction-side second rocker arm 44 is integrally provided with a bowl-shaped pressure receiving portion 44c which is open to the cylinder block 13 side on the side opposite to the pressing arm portions 44a and 44b with respect to the suction-side second rocker shaft 58, and is provided on the exhaust side. On the exhaust side second rocker arm 45 opposite to the pressing arm 45a with respect to the second rocker shaft 59, a bowl-shaped pressure receiving portion 45b opened toward the cylinder block 13 is integrally provided.
[0032]
The intake-side and exhaust-side push rods 46 and 47 extend from the valve operating chamber 48 to a part of the inside of the oil return passage 49, and the spherical ends at one end of the intake-side and exhaust-side push rods 46 and 47 are The spherical ends of the other end sides of the intake and exhaust push rods 46, 47 are fitted to the pressing portions 42a, 43a of the first rocker arms 42, 43 on the intake side and the exhaust side, respectively. The rocker arms 44 and 45 are fitted to the pressure receiving portions 44c and 45b of the second rocker arms 44 and 45 in a swingable manner.
[0033]
In such a valve operating device 38, the intake-side first rocker arm 42 swings by the intake-side cam 39 in accordance with the rotation of the camshaft 41 to which the rotational power is transmitted from the crankshaft at a reduction ratio of 1/2. As a result, the intake-side push rod 46 operates in the axial direction, and the intake-side second rocker arm 44 swings accordingly, whereby the first and second intake valves 27 and 28 are opened and closed. As the exhaust-side first rocker arm 43 swings, the exhaust-side push rod 47 operates in its axial direction, and the exhaust-side second rocker arm 45 swings accordingly, whereby the exhaust valve 29 is opened and closed. become.
[0034]
The injector 25 is supplied with compressed air from a reciprocating air pump 61 that reciprocates a piston 66 in a direction parallel to the cylinder axis C. The air pump 61 is provided on the cylinder head 14. The exhaust port 24 is disposed below the cylinder block 13 on the side corresponding to the exhaust port 24. Further, in the cylinder block 13, a working chamber 62 disposed below the cylinder bore 16 is formed so as to be connected to the oil return passage 49 in a substantially L-shape in a plane perpendicular to the cylinder axis C, and The pump 61 is disposed below the oil return passage 49 in a portion where the oil return passage 49 and the working chamber 62 are connected to each other.
[0035]
8, the pump case 63 of the air pump 61 has an axis parallel to the cylinder axis C and is formed integrally with the cylinder block 13 in a closed-end cylindrical shape with the cylinder head 14 side opened. A cover member 64 for closing the opening of the pump case 63 on the cylinder head 14 side in an airtight manner is fastened to the cylinder block 13. Moreover, the lid member 64 is coupled to the pump case 63 on the same plane as the coupling surface 87 of the cylinder block 13 and the cylinder head 14.
[0036]
The piston 66 is slidably fitted to the pump case 63, and is disposed between the one end of the piston 66 and the cover member 64 on the cylinder head 14 side so as to generate compressed air in accordance with volume contraction. A pump chamber 65 is formed, and an atmospheric pressure chamber 88 arranged on the oil pan 12a side is formed between the other end of the piston 66 and the closed end of the pump case 63.
[0037]
On the other hand, in the working chamber 62, a cylindrical bearing member 69 having an axis parallel to the axis of the camshaft 41 and passing through the axis of the piston 66 is disposed. A plurality of, for example, four fastening bosses 70... Moreover, a cover 72 forming the outer side surface of the working chamber 62 is fastened to the cylinder block 13, and when the cover 72 is opened, the bolts 71 can be tightened and loosened.
[0038]
A pump drive shaft 73 is coaxially inserted into the bearing member 69, and a roller bearing 74 is interposed between one end of the bearing member 69 and the pump drive shaft 73. A ball bearing 75 is interposed between the shafts 73. That is, the pump drive shaft 73 is rotatably supported by the bearing member 69 fastened to the cylinder block 13.
[0039]
The power from the camshaft 41 is transmitted to the pump drive shaft 73 via a power transmission means 89 at a portion protruding from one end of the bearing member 69. The power transmission means 89 A second driven sprocket 78 fixed to 73, a second driven sprocket 79 integral with the first driven sprocket 52 coupled to the camshaft 41, and an endless loop wound around the second driven and driven sprockets 78, 79. And a chain 80 as a transmission band.
[0040]
The pump drive shaft 73 is connected to a piston 66 of the air pump 61 via a scotch / yoke type crank 84, and the scotch / yoke type crank 84 is slidably fitted to the piston 66. And a tip of an eccentric shaft 73a projecting from an eccentric position of one end of the pump drive shaft 73. The eccentric shaft 73a rotates around the axis of the pump drive shaft 73 in response to the rotation of the pump drive shaft 73 by the power transmitted from the camshaft 41, and the piston 66 of the air pump 61 has the capacity of the pump chamber 65. Is reciprocally driven in the axial direction in the pump case 63 so as to increase or decrease.
[0041]
The piston 66 is provided with a sliding hole 67 having an axis arranged on a plane along one diameter line and orthogonal to the axis of the camshaft 41, and the sliding piece 68 is slidable in the sliding hole 67. Is fitted to. Further, the eccentric shaft 73a is integrally provided at one end of the pump drive shaft 73 so as to protrude.
[0042]
The pump case 63 is provided with an opening 76 into which one end of the pump drive shaft 73 is inserted, and the piston 66 has an eccentric shaft 73 a formed on the axis of the sliding hole 67 in accordance with the rotation of the pump drive shaft 73. An insertion hole 77 into which the eccentric shaft 73a is inserted so as to allow the eccentric shaft 73a to move in a direction along the length of the sliding hole 67 is provided so as to communicate with the center of the sliding hole 67 in the longitudinal direction.
[0043]
Through holes 81 and 82 are provided at both sides of the bearing member 69 at the center between the ball bearing 75 and the roller bearing 74, and the bearing member 69 has a working chamber at a position corresponding to one of the through holes 81. An oil guide 83 for guiding a part of the oil falling into the space 62 between the bearing member 69 and the pump drive shaft 73 is provided integrally. That is, a passage 134 provided in the cylinder head 14 is provided in the cylinder head 14 so as to guide a part of oil accumulated in a lower portion in the valve operating chamber 48, and a passage that opens to the working chamber 62 through the passage 134. Although 135 is provided in the cylinder block 13, an oil guide 83 is provided integrally with the bearing member 69 so as to guide oil falling from the passage 135 to the through hole 81. Further, a part of the oil introduced between the bearing member 69 and the pump drive shaft 73 is used for lubrication of the roller bearing 74 and the ball bearing 75, and the remaining part falls from the through hole 82 to a lower part in the working chamber 62. The oil accumulated in the lower part of the working chamber 62 is returned to the oil pan 12a from a return passage 136 provided in the cylinder block 13 so as to communicate with the lower part of the working chamber 62.
[0044]
On the cylinder block 13 on the opposite side of the air pump 61 with respect to the bearing member 69, a water pump 90 as an accessory having a rotation axis coaxial with the pump drive shaft 73 is attached. The air pump 61 and the water pump 90 are arranged at positions symmetrical with respect to a plane PL perpendicular to the drive shaft 73.
[0045]
A pump housing 91 of the water pump 90 has a housing main body 92 formed by integrally connecting a dish-shaped portion 92b to an open end of a bottomed cylindrical portion 92a having a closed pump drive shaft 73 side, and an open end of the housing main body 92. The pump cover 93 is fastened to the cylinder block 13 such that the outer periphery of the open end of the housing main body 92 is sandwiched between the pump cover 93 and the cylinder block 13.
[0046]
At the center of the closed end of the bottomed cylindrical portion 92a and the center of the pump cover 93, both ends of a pump shaft 94 which is coaxial with the pump drive shaft 73 are rotatably supported, and rotate integrally with the pump shaft 94. A plurality of magnets 96 are fixed to the rotor 95 inserted into the bottomed cylindrical portion 92a in this manner. On the other hand, a rotating member 97 having a cylindrical portion 97a coaxially surrounding a bottomed cylindrical portion 92a of the housing main body 92 is fixed to the other end of the pump drive shaft 73 protruding from the other end of the bearing member 69. A plurality of magnets 98 are fixed to the inner surface of the cylindrical portion 97a. Accordingly, the rotor 95 rotates with the pump shaft 94 in response to the rotation of the rotating member 97 with the pump drive shaft 73.
[0047]
Incidentally, a vortex chamber 99 is formed between the housing main body 92 and the pump cover 93, and the impeller 100 housed in the vortex chamber 99 is provided on the rotor 95.
[0048]
The pump cover 93 is provided with a plurality of suction ports 101 opening at the center of the vortex chamber 97, and the cooling water sucked into the vortex chamber 99 from the suction ports 101 is pressurized by the rotation of the impeller 100. The cooling water discharged from the water pump 90 is supplied to the block-side water jacket 102 provided on the cylinder block 13 and the head-side water jacket 103 provided on the cylinder head 14 through the block-side water jacket 102. Depending on the temperature of the cooling water, a state in which the cooling water discharged from the head-side water jacket 103 is guided to a radiator or the like (not shown) and a state in which the cooling water is returned to the suction ports 101 by bypassing the radiator or the like are provided. Switching is performed by the thermostat 104, and the thermostat housing 105 of the thermostat 104 is formed integrally with the pump cover 93 of the water pump 90.
[0049]
In the upper side wall of the pump case 63 in the air pump 61, an oil introduction hole 85 for guiding a part of the oil flowing through the oil return passage 49 into the pump case 63 for lubrication is formed so as to communicate with the oil return passage 49. Provided. By the way, the rotation in the oil return passage 49 causes the intake cam 39 and the exhaust cam 40 of the camshaft 41 to lift up a part of the oil flowing in the oil return passage 49 and separate and scatter the oil by the action of centrifugal force. In addition, a part of the oil supplied from the oil supply path 37 is separated and scattered by the action of centrifugal force. The relative position has been set.
[0050]
The width of the portion of the oil return passage 49 corresponding to the valve gear 38 is formed to be larger than that of the other portion, and corresponds to the intake cam 39 and the exhaust cam 40 of the camshaft 41. A projecting wall 86 that surrounds the portion to be formed in a substantially semicircular shape is integrally formed with the cylinder block 13 so as to face the oil flow direction 137 in the oil return passage 49, and the oil return of the air pump 61 is performed. The hole 85 is disposed immediately upstream of the protruding wall 86 along the oil flow direction 137. That is, the protruding wall 86 functions to guide the oil flowing through the oil return passage 49 to the oil introduction hole 85.
[0051]
Moreover, the oil return hole 85 is opened on the inner periphery of the pump case 63 on the atmospheric pressure chamber 88 side of the piston ring 138 mounted on the outer periphery of the piston 66 and slidably in contact with the inner periphery of the pump case 63. The oil return hole 85 always communicates with one end of a slide hole 67 provided in the piston 66 regardless of the axial movement of the piston 66. A pair of grooves 139... Connecting the end of the piston 66 on the atmospheric pressure chamber 88 side and both ends of the sliding hole 67 are provided on the outer periphery of the piston 66, and are introduced into the pump case 63 from the oil return hole 85. Part of the oil is used for lubrication between the piston 66 and the pump case 63, and the remainder flows toward the atmospheric pressure chamber 88 through the grooves 139. Moreover, the grooves 139 also serve to prevent the oil in the sliding hole 67 from leaking out, thereby preventing the pumping action of the sliding piece 68 in the Scotch and yoke type crank 84 from occurring.
[0052]
Thus, the oil flowing into the atmospheric pressure chamber 88 flows from the opening 76 to the working chamber 62 side, and further flows from the return passage 136 to the oil pan 12a side.
[0053]
Paying particular attention to FIG. 7, the injector 25 has an air fuel injection valve 107 having a nozzle 106 that enters the combustion chamber 19 and attached to the cylinder head 14, and injects fuel into the air fuel injection valve 107 from the rear. The fuel injection valve 107 is connected to the air fuel injection valve 107 in such a manner that the fuel injection valve 107 directly injects the fuel into the combustion chamber 19 together with the compressed air.
[0054]
The cylinder head 14 has a fitting hole 109 for tightly fitting the nozzle 106, and an insertion cylinder 110 having an inner diameter larger than the fitting hole 109 and coaxially connected to the fitting hole 109. The air fuel injection valve 107 is provided coaxially with the cylinder axis C. The air fuel injection valve 107 has an annular step formed between the fitting hole 109 and the insertion cylinder 110 while the nozzle 106 is airtightly fitted into the fitting hole 109. It is inserted into the insertion tube 110 until it comes into contact with the portion 111. In addition, the wire connecting portion 107a provided at the rear portion of the air fuel injection valve 107 is disposed in a notch 110a provided at the rear end of the insertion tube 110, and a pair of wires derived from the wire connecting portion 107a outside the insertion tube 110. Are penetrated to the outside through the grommet 113 sandwiched between the mating surfaces of the cylinder head 14 and the head cover 15.
[0055]
On the other hand, a cylindrical injector housing 114 for fitting and holding the fuel injection valve 108 and for holding the air fuel injection valve 107 between the head cover 15 and the cylinder head 14 is formed integrally with the head cover 15. At the time of connection to the cylinder head 14, the front end of the injector housing 114 comes into contact with the rear end of the air fuel injection valve 107. A holding plate 115 for holding the rear end of the fuel injection valve 108 between the injector housing 114 and the injector housing 114 is fastened to the rear end of the injector housing 114.
[0056]
An annular fuel chamber 116 communicating with the fuel injection valve 108 is formed between the injector housing 114 and the fuel injection valve 108, and a pair of seal members 117 and 118 sandwiching the fuel chamber 116 from both sides are used for fuel injection. It is interposed between the valve 108 and the injector housing 114.
[0057]
In addition, a fuel supply passage 119 communicating with the fuel chamber 116 is provided directly on the head cover 15, and a hose 120 for guiding fuel from a fuel supply source (not shown) is connected to the fuel supply passage 119 via a joint 121.
[0058]
An annular air chamber 122 communicating with the air fuel injection valve 107 is formed between the front end of the fuel injection valve 108, the rear end of the air fuel injection valve 107, and the injector housing 114. Compressed air from the air pump 61 is supplied to the chamber 122.
[0059]
2 and 8, the lid member 64 of the air pump 61 is provided with a suction pipe 124 to which a hose for guiding air from an air cleaner (not shown) is connected. It is connected to the pump chamber 65 via a built-in reed valve (not shown).
[0060]
The lid member 64 has a built-in poppet valve 125 that opens in response to an increase in the pressure of the pump chamber 65, and compressed air discharged from the air pump 61 passes through the poppet valve 125 and the compressed air supply passage 126. The air is supplied to the air chamber 122.
[0061]
The compressed air supply passage 126 is connected to the lid member 64 at one end so as to be connected to the poppet valve 125, and the other end is connected to the cylinder head 14. A passage 128 is provided directly on the head 14, and a passage 129 is provided directly on the head cover 15 so as to communicate with the passage 128 and the air chamber 122.
[0062]
In addition, a part of the passage 128 directly provided in the cylinder head 14 passes near the exhaust port 24, and particularly, in the vicinity of the exhaust port 24, the head-side water jacket 103 moves between the exhaust port 24 and the cylinder block 13. In contrast, the passage 128 is set so as to pass through the opposite side of the head side water jacket 103 with respect to the exhaust port 24.
[0063]
Both ends of a cylindrical knock pin 130 that straddles the mating surface of the cylinder head 14 and the head cover 15 are inserted into the cylinder head 14 and the head cover 15, and constitute a part of the compressed air passage 126 to form the cylinder head 14 and the head cover 15. Are directly communicated with each other through the knock pin 130. Moreover, the O-ring 133 surrounding the knock pin 130 is sandwiched between the mating surfaces of the cylinder head 14 and the head cover 15.
[0064]
An orifice 131 is formed in the knock pin 130, and a relief valve 132 connected to the passage 128 on the upstream side of the orifice 131 is attached to the cylinder head 14.
[0065]
Next, the operation of this embodiment will be described. At least a portion of the valve train 38 is provided between the cylinder head 14 and the head cover 15 which constitute a part of the engine body 11 in a four-cycle overhead valve type engine. A valve operating chamber 48 for accommodating and disposing upper portions of the intake-side and exhaust-side second rocker arms 44 and 45 and the intake-side and exhaust-side push rods 46 and 47 is formed. The cylinder block 13 and the cylinder head 14 have an oil return passage 49 for returning oil, which has lubricated a portion of the valve train 38 housed in the valve train chamber 48, to an oil pan 12 a formed in the lower portion of the crankcase 12. Are formed so as to extend parallel to the cylinder axis C on the side of the cylinder bore 16. Moreover, an oil introduction hole 85 for introducing a part of the oil flowing through the oil return passage 49 into the pump case for lubrication is provided in the pump case 63 of the air pump 61 disposed below the oil return passage 49. It is provided so as to communicate with the oil return passage 49.
[0066]
Therefore, a part of the oil returning to the oil pan 12a after lubricating a part of the valve gear 38 is surely guided to the oil introduction hole 85 of the air pump 61, and the lubrication of the air pump 61 is ensured with a simple structure. Can be fulfilled.
[0067]
In addition, since the pump case 63 is integrally formed with the cylinder head 13 and the cylinder block 13 having a smaller outer shape than the crankcase 12 which cooperate with the engine body 11, the number of parts can be reduced and the overall size of the engine can be reduced. Therefore, communication between the oil return passage 49 and the oil introduction hole 85 can be facilitated, and the structure for supplying oil to the air pump 61 can be simplified.
[0068]
In the oil return passage 49, a first driven sprocket 52, a first driving sprocket 60, and a cam chain 53 for transmitting power from the crankshaft 10 to the camshaft 41 of the valve train 38 are accommodated. By using the first driven sprocket 52, the first drive sprocket 60, and the cam chain 53 as the oil return passage 49, it is possible to reduce the size of the engine and to simplify the structure for supplying oil to the air pump 61.
[0069]
Further, the camshaft 41 is accommodated and arranged in the oil return passage 49, and the camshaft 41 and the oil are arranged so that the oil droplets separated by the action of centrifugal force with the rotation of the camshaft 41 are guided to the oil introduction hole 85 side. Since the relative position of the introduction hole 85 is set, the camshaft 41 is satisfactorily lubricated with the oil flowing through the oil return passage 49, and the oil droplets scattered by the rotation of the camshaft 41 are removed by the air pump 61. And the lubrication of the air pump 61 can be improved.
[0070]
A power transmission means 89 for transmitting the power of the camshaft 41 to the pump drive shaft 73 is provided between the pump drive shaft 73 and the camshaft 41 connected to the air pump 61, and the camshaft 41 for driving the air pump 61 is provided. By disposing the power transmission means 89 in the vicinity of the air pump 61, the structure of the power transmission means 89 can be simplified and the size of the engine can be reduced.
[0071]
Moreover, since the camshaft 41 is also disposed in the cylinder block 13 having a relatively small outer shape, it is possible to further contribute to downsizing of the engine, and power transmission means 89 for transmitting the power from the camshaft 41 to the air pump 61. Can be made compact, and the degree of freedom in setting the gear ratio of the air pump 61 is also increased. In addition, since the power transmission means 89 is configured to transmit power by the endless chain 80, the size of the cylinder block 13 is prevented from being increased regardless of the distance between the camshaft 41 and the pump drive shaft 73. However, the number of parts can be reduced.
[0072]
In the cylinder block 13, a protruding wall 36 facing the oil flow direction 137 in the oil return passage 49 is provided so as to project oil at a lower portion in the oil return passage 49 to the oil introduction hole 85. The lubrication of the air pump 61 can be further improved by effectively guiding the oil to the oil introduction hole 85 by the projecting wall 86.
[0073]
The air pump 61 is of a reciprocating type, and can obtain a relatively high air pressure. Further, the pump drive shaft 73 to which the power from the camshaft 41 for reciprocating the piston 66 in a direction parallel to the cylinder axis C is transmitted is connected to the piston 66 via the Scotch-yoke type crank 84, so that the air pump 61 By making the operating axis and the cylinder axis C parallel to each other and using a scotch-yoke type crank 84 to eliminate the need for a connecting rod, the size of the engine can be reduced.
[0074]
The air pump 61 is provided with a pump chamber 65 disposed on the cylinder head 14 side to generate compressed air in accordance with volume contraction, and an atmospheric pressure disposed on the oil pan 12a side through the oil pan 12a. A piston 66 having both ends facing the chamber 88 is slidably fitted to the pump case 63. The piston 66 is mounted on the outer periphery of the piston 66 and slidably contacts the inner periphery of the pump case 63. On the 88 side, the oil introduction hole 85 opens in the inner periphery of the pump case 63, so that the lubricated oil in the air pump 61 is moved from the atmospheric pressure chamber 88 to the oil pan 12 a by the pumping action of the piston 66. As a result, the operation efficiency and lubrication of the air pump 61 can be improved.
[0075]
The pump case 63 of the air pump 61 is formed integrally with the cylinder block 13 in a cylindrical shape having a bottom with the cylinder head 14 side open, and a lid for closing the opening of the pump case 63 on the cylinder head 14 side in an airtight manner. Since the member 64 is coupled to the pump case 63 on the same plane as the coupling surface 87 of the cylinder block 13 and the cylinder head 14, the number of processing steps for the cylinder block 13 can be reduced.
[0076]
Further, the air pump 61 and the water pump 90 connected to both ends of the pump drive shaft 73 are disposed at positions symmetrical with respect to a plane PL including the cylinder axis C and orthogonal to the pump drive shaft 73. The water pump 90 is driven by the pump drive shaft 73 connected to 61, so that the number of parts can be reduced and the weight can be reduced, and the cost can be reduced by simplifying processing and assembly. In addition, it is possible to suppress the water pump 90 from projecting from the cylinder block, and to avoid increasing the size of the entire cylinder block 13.
[0077]
In addition, the water pump 90 can be arranged near the cylinder block 13 and the cylinder head 14 to be water-cooled, so that the water pipe can be shortened, the pipe can be prevented from being complicated, and the pressure loss in the pipe can be reduced. be able to.
[0078]
Further, since the injector 25 for directly injecting the fuel into the combustion chamber 19 together with the compressed air obtained by the air pump 61 is provided in the cylinder head 14, the air pump 61 is not provided in the cylinder head 14, so that the layout is free. The injector 25 and its piping can be disposed in the cylinder head 14 while increasing the degree of size and miniaturizing the engine. In particular, since the pump chamber 65 of the air pump 61 is arranged on the cylinder head 14 side, the distance between the pump chamber 65 and the injector 25 is relatively short, and the compressed air supply passage 126 for guiding the compressed air from the air pump 61 to the injector 25 is provided. Can be avoided, and the pressure loss in the pipe structure can be suppressed to be small.
[0079]
A part of the compressed air supply passage 126 passes near the exhaust port 24, so that the compressed air flowing through the compressed air supply passage 126 can be heated by the exhaust heat of the exhaust gas flowing through the exhaust port 24. The pump efficiency can be improved by increasing the volume of the compressed air.
[0080]
Moreover, in the vicinity of the exhaust port 24, a part of the head-side water jacket 103 is disposed between the exhaust port 24 and the cylinder block 13, whereas a part of the compressed air supply path 126 is formed in the passage 128. Are disposed on the opposite side of the head side water jacket 103 with respect to the exhaust port 24, so that the effect of cooling by the head side water jacket 103 can be minimized from affecting the compressed air flowing through the compressed air supply path 126, High pump efficiency can be maintained even with a water-cooled engine.
[0081]
The air pump 61 is disposed below the cylinder block 13 on the side corresponding to the exhaust port 24, and the air pump 61 is disposed in an engine arrangement space including an exhaust pipe connected to the exhaust port 24. It is possible to do.
[0082]
The fuel injection valve 108 of the injector 25 is fitted and held in the injector housing 114. Since the injector housing 114 is formed integrally with the head cover 15, the injector housing 114 is formed around the cylinder head 14. Therefore, it is not necessary to dispose a member to be used, so that it is possible to reduce the number of parts and to avoid an increase in the size of the engine and a complicated structure around the engine.
[0083]
Further, a fuel supply passage 119 for supplying fuel and compressed air to the injector housing 114 and a passage 129 which is a part of the compressed air supply passage 126 are provided directly on the head cover 15. There is no need to arrange pipes and the like for supplying fuel and compressed air around the injector housing 114, which can reduce the number of parts, increase the size of the engine, and complicate the structure around the engine. Can be avoided.
[0084]
By the way, the camshaft 41 which constitutes a part of the valve operating device 38 for driving the first intake valve 27, the second intake valve 28 and the exhaust valve 29 disposed on the cylinder head 14 includes the cylinder head 14 and the head cover. It is arranged on the cylinder block 13 so as to avoid the space between the 15 blocks. Therefore, the camshaft 41 is not disposed between the cylinder head 14 and the head cover 15, so that the degree of freedom of the layout of the injector housing 114 can be increased, and the fuel supply passage 119 and the passage provided directly on the head cover 15 can be provided. 129 can increase the degree of freedom of the layout.
[0085]
Further, the injector 25 is disposed on the cylinder axis C, and the first intake valve port 20 and the exhaust valve port 22 are disposed on both sides of the injector 25 on a projection on a plane orthogonal to the cylinder axis C, Since the second intake valve port 22 is arranged on one side of the injector 25 on another straight line L2 substantially orthogonal to the straight line L1 connecting the first intake valve port 20 and the exhaust valve port 22, the injector 25 is burned. By arranging it in the center of the chamber 19, it is possible to improve the combustion efficiency by eliminating the bias in the flame propagation distance in the combustion chamber 19, and the first and second intake valve ports 20, 21 are provided. As a result, the air filling efficiency can be improved and the pumping loss can be reduced. Can be arranged, it is possible to improve the combustion efficiency as possible the close proximity to the injector 25 of the spark plug 26.
[0086]
The air fuel injection valve 107 of the injector 25 is supported by the head cover 15, and a passage 129, which is a part of a compressed air supply path 126 that supplies compressed air to the air fuel injection valve 107, is provided directly on the head cover 15. In addition, since components for guiding the compressed air to the injector 25 are not arranged around the head cover 15, it is possible to avoid an increase in the size of the engine and a complicated structure around the engine.
[0087]
Further, both ends of a cylindrical knock pin 130 that straddles the mating surface of the cylinder head 14 and the head cover 15 are inserted into the cylinder head 14 and the head cover 15, and form a part of the compressed air passage 126 to form the cylinder head 14 and the head cover 15. The passages 128 and 129 provided directly are communicated with each other through the knock pin 130, so that the relative positions of the cylinder head 14 and the head cover 15 are determined by the knock pin 130, and the injector 25 cooperates with the head cover 15 and the cylinder head 14. Even if the injector 25 is supported, no excessive stress is applied to the injector 25. Further, since the knock pin 130 is used as a connecting member for the passage 128 of the cylinder head 14 and the passage 129 of the head cover 15, a dedicated component for connecting the passage is not required, and the number of components can be reduced.
[0088]
Further, since the orifice 131 is formed in the knock pin 130, the pressure of the compressed air supplied to the injector 25 can be adjusted, and a dedicated component is not required for the pressure adjustment, thereby contributing to a reduction in the number of components.
[0089]
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.
[0090]
For example, in the above embodiment, the power transmission means 89 including the endless chain 80 is provided between the camshaft 41 and the pump drive shaft 73. However, the power transmission means including the endless transmission belt is provided between the camshaft 41 and the pump drive shaft 73. It may be provided between the shafts 73.
[0091]
【The invention's effect】
As described above, according to the first aspect of the present invention, the pump case is formed integrally with the cylinder block having a relatively small outer shape, so that the size of the entire engine can be reduced while reducing the number of parts. Since the camshaft for driving the air pump is also arranged in the cylinder block, the power transmission means for transmitting the power from the camshaft to the air pump can be made compact, and the degree of freedom in setting the gear ratio of the air pump is increased. .
[0092]
Further, according to the second aspect of the present invention, it is possible to prevent the cylinder block from increasing in size and reduce the number of parts regardless of the distance between the camshaft and the pump drive shaft.
[0093]
According to the third aspect of the present invention, the auxiliary equipment is driven by the pump drive shaft connected to the air pump, so that the number of parts and the weight can be reduced, and the cost can be reduced by simplifying the processing and assembly. Become. In addition, the protrusion of the accessory from the cylinder block can be suppressed, and an increase in the size of the entire cylinder block can be avoided.
[0094]
According to the fourth aspect of the present invention, by disposing the water pump in the vicinity of the cylinder block and the cylinder head to be water-cooled, the water pipe can be shortened, and the pipe can be prevented from being complicated, and the inside of the pipe can be reduced. Pressure loss can be reduced.
[0095]
According to the fifth aspect of the invention, a relatively high air pressure can be obtained, the operating axis of the air pump and the cylinder axis of the engine are made parallel, and a scotch-yoke type crank is used to eliminate the need for a connecting rod. This makes it possible to reduce the size of the engine.
[0096]
According to the sixth aspect of the invention, the number of processing steps for the cylinder block can be reduced.
[0097]
Further, according to the present invention, the injector and its piping can be arranged in the cylinder head while increasing the degree of freedom of layout and miniaturizing the engine. In particular, the pump chamber of the air pump can be provided in the cylinder head. When disposed on the side, the distance between the pump chamber and the injector is relatively short, the complexity of the pipe structure connecting the air pump and the injector can be avoided, and the pressure loss in the pipe structure can be reduced. .
[Brief description of the drawings]
FIG. 1 is a partial longitudinal side view of an engine.
FIG. 2 is a view taken along line 2-2 of FIG. 1 with a head cover removed.
FIG. 3 is a sectional view taken along line 3-3 of FIG. 2;
FIG. 4 is a sectional view taken along line 4-4 of FIG. 3;
FIG. 5 is a sectional view taken along line 5-5 of FIG. 2;
FIG. 6 is a sectional view taken along line 6-6 in FIG. 5;
FIG. 7 is a sectional view taken along line 7-7 of FIG. 5;
FIG. 8 is a longitudinal sectional side view of the engine taken along line 8-8 in FIG. 2;
[Explanation of symbols]
13 ... Cylinder block
14 ... Cylinder head
25 ・ ・ ・ Injector
38 ... valve gear
41 ・ ・ ・ Camshaft
61 ・ ・ ・ Air pump
63 ・ ・ ・ Pump case
64 ... lid member
66 ・ ・ ・ Piston
73 ・ ・ ・ Pump drive shaft
80 ... Chain as drive band
84 ・ ・ ・ Scotch yoke type crank
87 ... connecting surface
89 ・ ・ ・ Power transmission means
90 ・ ・ ・ Water pump as auxiliary equipment
C: Cylinder axis
PL: plane

Claims (7)

An air pump driving device for driving an air pump (61) by an engine, wherein the engine forms a camshaft (41) which is a part of a valve train (38) and is disposed on a cylinder block (13). The pump case (63) of the air pump (61) to which power from the camshaft (41) is transmitted is formed integrally with the cylinder block (13). And air pump drive. A power transmission means (89) including an endless power transmission band (80) is provided between a pump drive shaft (73) connected to the air pump (61) and the camshaft (41). 2. The air pump driving device according to 1. The air pump coupled to both ends of the pump drive shaft (73) at positions that are plane-symmetric with respect to a plane (PL) orthogonal to the pump drive shaft (73) including the cylinder axis (C) of the engine. The air pump drive according to claim 2, characterized in that the (61) and the auxiliary device (90) are arranged. The air pump driving device according to claim 3, wherein the engine is a water-cooled type, and the auxiliary device is a water pump (90). The air pump (61) is of a reciprocating type that reciprocates a piston (66) in a direction parallel to a cylinder axis (C) of the engine, and is driven by a pump to which power from the camshaft (41) is transmitted. An air pump drive according to any of the preceding claims, wherein a shaft (73) is connected to said piston (66) via a Scotch and yoke crank (84). The pump case (63) of the air pump (61) has an axis parallel to the cylinder axis (C) of the engine and has a bottomed cylindrical shape with the cylinder head (14) side open, and is integrated with the cylinder block (13). And a lid member (64) for hermetically closing the opening on the cylinder head (14) side of the pump case (63) is the same as the coupling surface (87) of the cylinder block (13) and the cylinder head (14). 6. The air pump drive according to claim 5, wherein the drive is coupled to the pump case in a plane. The injector (25) for directly injecting fuel into a combustion chamber together with compressed air supplied from the air pump (61) is provided in the cylinder head (14). An air pump drive as described.

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