JP2005036776A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the overall width of an internal combustion engine in the internal combustion engine having a water pump. <P>SOLUTION: In this engine 15, a water pump driving sprocket 159 is installed between a journal part 170 at one end of a crankshaft 47 and a camshaft driving sprocket 147 rotating the camshaft, a water pump 55 is disposed on the right side wall 43a of a cylinder block 43, and a pump driving chain 148 is wrapped around between the rotating shaft 157 of the water pump 55 and the water pump driving sprocket 159. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an internal combustion engine having a water pump for circulating cooling water.

Some internal combustion engines such as two-wheeled vehicles have a water pump that circulates cooling water through a cylinder head or a cylinder block (for example, see Patent Document 1).
In Patent Document 1, a camshaft accommodated in a cylinder head is provided with a sprocket around which a cam chain is wound around a crankshaft. The cam chain is accommodated in a cam chain chamber defined by the cylinder head, and a water pump is disposed on the outer wall of the cam chain chamber. The rotating shaft of the water pump protrudes from the outer wall into the cam chain chamber and is fitted to one end of the cam shaft. When the crankshaft rotates, the cam chain is driven and the camshaft rotates. The fitted rotating shaft also rotates. When the rotating shaft rotates, the impeller attached to the rotating shaft in the water pump rotates, and the cooling water flowing through the water pump is pressurized and pumped to the cylinder head and the cylinder block.
Japanese Patent Laid-Open No. 2002-220552 (paragraph numbers 0013 to 0024, FIG. 1)

However, when the water pump is attached to the outer wall of the cylinder head and the rotating shaft is directly connected to the camshaft, the end of the rotating shaft of the water pump is located outside the cam chain. Therefore, the water pump protrudes greatly from the side surface of the internal combustion engine, and the length of the entire internal combustion engine in the vehicle width direction increases.
This invention is made in view of such a subject, and it aims at arrange | positioning a water pump, without increasing the width | variety of the whole internal combustion engine.

  The invention according to claim 1 of the present invention that solves the above problem is a cam that drives a camshaft (for example, the camshafts 85 and 86 of the embodiment) to one end of a crankshaft (for example, the crankshaft 47 of the embodiment). In an internal combustion engine provided with a shaft drive sprocket (for example, the camshaft drive sprocket 149 of the embodiment), the camshaft drive sprocket and the water pump drive sprocket (for example, the water pump drive of the embodiment) are provided on the crankshaft. Sprocket 147) is disposed, the water pump driving sprocket is disposed inside the crankshaft axis (for example, the axis C in the embodiment), and the camshaft driving sprocket is disposed outside the water pump driving sprocket. Placed on the wall A water pump for circulating cooling water (for example, the water pump 55 of the embodiment) is driven by a chain (for example, the pump drive chain 148 of the embodiment) wound around a sprocket for driving the pump. For example, the engine 15) of the embodiment.

  According to this internal combustion engine, the rotation of the crankshaft can be transmitted via the chain to drive the water pump, so that the water pump and the crankshaft or camshaft can be separated. In addition, the water pump drive sprocket that winds the chain on the crankshaft side is inside the crankshaft axial direction relative to the camshaft drive sprocket, so the water pump and crankshaft are partly overlapped in plan view Is done. Thereby, compared with the case where the rotating shaft of a water pump is directly connected with a crankshaft or a camshaft, a water pump can be arrange | positioned in the center side of the vehicle width direction.

The invention according to claim 2 is the internal combustion engine according to claim 1, wherein the water pump is arranged in the vicinity of a cylinder (for example, the cylinder 50 of the embodiment).
According to this internal combustion engine, the water pump is arranged above the internal combustion engine.

According to a third aspect of the present invention, in the internal combustion engine according to the first aspect, the water pump overlaps the cylinder at a rear side of the center line of the cylinder (for example, the cylinder center line SC of the embodiment) and in a side view. It is characterized by being arranged at a position.
According to this internal combustion engine, the space behind the cylinder can be effectively used as the space for arranging the water pump.

According to the first aspect of the present invention, since the water pump drive sprocket is disposed near the center of the crankshaft in the axial direction, the water pump and the crankshaft can be disposed so as to partially overlap in plan view. The width of the internal combustion engine can be reduced.
According to the second aspect of the invention, the width of the internal combustion engine can be reduced and the water pump is disposed in the vicinity of the cylinder of the internal combustion engine, so that the cooling water can be easily passed through the upper part of the internal combustion engine. In addition, when such an internal combustion engine is mounted on a vehicle, the turning performance of the vehicle can be improved because the water pump is disposed at a high position.
According to the third aspect of the present invention, the width of the internal combustion engine in the vehicle width direction can be shortened, and the water pump is disposed in the space behind the cylinder of the internal combustion engine, so that the internal combustion engine can be downsized.

  The best mode for carrying out the invention will be described in detail with reference to the drawings. In the following, the front side is the forward direction of the vehicle, and the rear side is the direction in which the vehicle moves backward. Further, the right side and the left side are the right side and the left side in the direction in which the vehicle advances.

As shown in FIG. 1, the front wheel 2 of the motorcycle 1 is pivotally supported by a front fork 3, and the front fork 3 is steered by a head pipe 6 provided at a front end portion of a vehicle body frame 5 via a top bridge 4. It is pivoted as possible. The rear wheel 7 of the motorcycle 1 is pivotally supported by a rear fork 8, and the rear fork 8 is pivotally supported by a pivot portion 9 and an engine 15 provided at an intermediate portion of the vehicle body frame 5. The upper end of the rear cushion unit 10 is attached to the vicinity of the pivot shaft of the rear fork 8, and the lower end of the rear cushion unit 10 is attached to the lower part of the engine 15 via the link mechanism 11. The shock is absorbed so that no impact is applied to the vehicle body via
From the upper part of the head pipe 6, the main frame 12 of the vehicle body frame 5 is divided into left and right parts and extends rearward and downward, and the rear end part thereof is bent downward and continues to the pivot part 9. A seat rail 13 of the vehicle body frame 5 is connected to the rear of the main frame 12. A fuel tank 14 is disposed above the main frame 12, and an engine 15 is disposed below the main frame 12.

A driver's seat 16 and a rear passenger's pillion seat 17 are respectively supported by the seat rails 13 behind the fuel tank 14. A driver step 18 is attached to the rear portion of the pivot portion 9 of the main frame 12, and a rear passenger step 19 is attached to the lower portion of the seat rail 13. Further, a pair of left and right handles 20 are attached to the upper end portion of the front fork 3.
A brake caliper 21 is attached to the lower end of the front fork 3, and a brake rotor 22 corresponding to the brake caliper 21 is attached to the front wheel 2 to constitute a front brake device 23. A rear brake device (not shown) having the same configuration as the front brake device 23 of the front wheel 2 is provided on the right side of the rear wheel 7.
The front part of the motorcycle 1 is covered with a front cowl 24, and the periphery of the seat rail 13 is covered with a rear cowl 25. A rear sprocket 26 is attached to the left side of the rear wheel 7, and a drive chain 28 is wound around the rear sprocket 26 and a drive sprocket 27 disposed on the left side of the rear portion of the engine 15 to drive the engine driving force to the rear wheel 7. Can be communicated to. A retractable side stand 29 is disposed at the lower left side of the vehicle body frame 5 and can support the motorcycle 1 in a standing state in which the vehicle body is inclined to the left.

  The engine 15 of the present embodiment is a water-cooled in-line four-cylinder engine, and the cylinder body 30 is disposed on the crankcase 31 in a slightly inclined state. A throttle body 32 corresponding to each cylinder is connected to a rear portion of the cylinder body 30, and each throttle body 32 is connected to an air cleaner case 33 disposed between the main frame 12 and the fuel tank 14. An exhaust pipe 34 corresponding to each cylinder is connected to the front portion of the cylinder body 30. The exhaust pipe 34 curves downward from the front wall of the cylinder body 30, passes through the crankcase 31, and then bends upward at the rear of the pivot portion 9 to connect to the silencer 35 supported by the seat rail 13. Is done.

  A radiator 36 is disposed in front of the exhaust pipe 34 with a slightly forward tilted attitude similar to the cylinder body 30. The radiator 36 is a round type whose front side is curved in a concave shape, and as shown in FIG. 2, a cross flow in which a cooling water inflow side tank 37 is provided on the right side of the radiator core 36a and an outflow side tank 38 is provided on the left side. This is a mold and is provided so as to extend from the upper part of the cylinder body 30 to the lower part of the crankcase 31 in the vertical direction. A pair of left and right radiator fans 39 (see FIG. 1) are attached to the upper back side of the radiator core 36a.

Here, the circulation channel of the cooling water will be described with reference to FIG.
The cooling water that has cooled the cylinder head 40 (see FIG. 3) of the engine 15 is supplied to the inflow side tank 37 of the radiator 36. The radiator 36 is connected to an outflow side radiator hose 56 from which the cooling water after heat exchange flows out. A branch pipe 66 is attached to the tip of the outflow side radiator hose 56, and the cooling water flowing out from the water-cooled oil cooler 65 joins the cooling water introduction hose 58. The cooling water introduced into the water pump 55 from the cooling water introduction hose 58 is pumped from a cooling water inlet (not shown) to the cylinder-side water jacket 57 shown in FIG. The cooling water is supplied to the water-cooled oil cooler 65 through the introduction hose 68. The cooling water flowing in from the cooling water inlet passes through the cylinder-side water jacket 57 and then flows into the head-side water jacket 60 of the cylinder head 40. A cooling water outlet 61 from the head-side water jacket 60 is provided at the rear portion of the Linda head 40. A thermostat 62 is directly attached to the cooling water outlet 61, and an inflow side radiator hose 63 communicating with the inflow side tank 37 of the radiator 36 is connected to the cooling water outlet of the thermostat 62, and the thermostat 62 and the water pump 55 are connected. A bypass hose 64 is disposed between the two. If the cooling water passing through the thermostat 62 is below a certain temperature, the cooling water is sent from the thermostat 62 to the water pump 55 through the bypass hose 64 and circulates without passing through the radiator 36. Further, when the cooling water passing through the thermostat 62 reaches a certain temperature or higher, the cooling water is introduced into the radiator 36 via the inflow side radiator hose 63 to cool the cooling water.

As shown in the left side view of FIG. 3 and the right side view of FIG. 4, the engine 15 includes a cylinder head 40, a cylinder block 43, and a crankcase 31, which are main components thereof. The cylinder head 40 is divided into a head body 41 and a head cover 42, and the crankcase 31 is divided into an upper case 44 and a lower case 45. The upper case 44 and the cylinder block 43 are integrally formed, and an oil pan 46 is attached under the lower case 45. Here, the head main body 41 is a cast product made of an aluminum alloy.

  A spark plug 70 is screwed into the head body 41 of the cylinder head 40 so as to face each combustion chamber, and an intake port 71 and an exhaust port 72 are formed to communicate each combustion chamber with the outside. A throttle body 32 is connected to the opening on the outside of each intake port 71, and an exhaust pipe 34 is connected to the opening on the outside of each exhaust port 72. In addition, valve seats are respectively attached to the openings on the combustion chamber side of the intake ports 71 and the exhaust ports 72, and these openings can be opened and closed by the operation of the intake valves 75 and the exhaust valves 76.

  As shown in FIG. 5, the intake valve 75 includes a valve stem 77 having an umbrella-shaped valve body that actually opens and closes the opening of the intake port 71, and biases the valve stem 77 upward so that the face surface of the valve body is a valve seat. The valve spring 78 is pressed against the opening 73 to close the opening, and the valve lifter 79 is mounted on the cylinder at the upper end of the valve stem 77. The valve stem 77 slides on the valve guide 80 mounted on the head body 41. It is inserted movably. Further, the exhaust valve 76 has the same configuration as the intake valve 75. That is, it is composed of a valve stem 81, a valve spring 82, a valve lifter 83, and the like.

  Above each intake valve 75 and exhaust valve 76, an intake side camshaft 85 and an exhaust side camshaft 86 that actuate them are arranged in parallel with the axis C of the crankshaft 47. On the peripheral surfaces of the intake side camshaft 85 and the exhaust side camshaft 86, intake side cams and exhaust side cams (not shown) corresponding to the intake valves 75 and the exhaust valves 76 are provided.

  In addition, cam sprockets (not shown) are provided at the right ends of the camshafts 85 and 86, and the camshafts 85 and 86 are linked to the crankshaft 47 through cam chains wound around the cam sprockets. . As the crankshaft 47 rotates, the camshafts 85 and 86 rotate, so that the intake valve 75 and the exhaust valve 76 can be operated. The camshafts 85 and 86 are hollow, and the hollow portion serves as a passage for engine oil (lubricating oil) L, and the engine oil L is supplied to each sliding surface from a predetermined oil hole.

Here, with reference to FIG. 6 as well, a circulation channel of the cooling water formed in the head main body 41 will be described.
First, plug holes 90 corresponding to the four cylinders 50 arranged in the vehicle body width direction are provided in the head main body 41 so that the spark plug 70 can be screwed to the vicinity of the center of the top of the combustion chamber.
The intake port 71 is branched into two from a main intake passage 92 that opens to the outside with respect to one combustion chamber to form a branch passage 93. Each branch passage 93 opens into the combustion chamber, and these Two openings are disposed behind the plug hole 90, and a valve seat 73 is attached to each opening. In addition, two openings to the combustion chamber of the exhaust port 72 are formed with respect to one combustion chamber. These two openings are arranged in front of the plug hole 90 and a valve seat 74 is attached to each opening. In other words, the two branch passages 94 of the exhaust port 72 communicate with the combustion chamber, and the two branch passages 94 gather to form the main exhaust passage 95.

  A plurality of communication ports 96 through which the cylinder-side water jacket 57 and the head-side water jacket 60 can communicate are formed on the mating surface 41 a of the head body 41 with the cylinder block 43. Specifically, a front communication port 96 a is provided in front of each exhaust port 72 opening on the mating surface 41 a, and each front communication port 96 a is formed in a substantially rectangular shape along the front surface of the head body 41. Similarly, rear communication ports 96 b are respectively provided behind the openings of the intake ports 71, and the rear communication ports 96 b are formed in a substantially rectangular shape along the rear surface of the head body 41.

  Further, assuming that each cylinder 50 is the first cylinder, the second cylinder,... In order from the left, on the mating surface 41a, the exhaust port 72 opening and the intake port 71 opening of the first cylinder and the fourth cylinder are located outside the cylinder row direction. Are provided with side communication ports 96c each having a substantially oval shape along the side surface of the head main body 41. Further, a pair of front and rear intermediate communication ports 96d each having a substantially triangular shape are provided between the cylinders 50, respectively.

  The inflow of cooling water into the head-side water jacket 60 is controlled by a through hole formed in a head gasket interposed between the head main body and the cylinder block 43. That is, by adjusting the shape, position, and area of the through hole formed in the head gasket and arbitrarily stopping or restricting the flow of cooling water into each communication port 96, the head main body 41 is relatively complicatedly arranged. The flow rate balance etc. of the cooling water in the head side water jacket 60 is controlled. In this embodiment, among the communication ports 96, the intermediate communication port 96d on the front side (exhaust port 72 side) between the second and third cylinders and the front communication ports located on both sides thereof. The cooling water flows into the head side water jacket 60 mainly through 96a.

  The head body 41 includes a cylindrical plug hole wall 91 that forms a plug hole 90, a branched tubular intake port wall 101 and exhaust port wall 102 that form an intake port 71 and an exhaust port 72, and the head body 41 and the cylinder block 43. A boss 103 and the like are formed. The portions of the intake port wall 101 and the exhaust port wall 102 near the valve seats 73 and 74 are densely packed around the plug hole wall 91, and are integrally formed so that the adjacent portions of these walls are fused. The head-side water jacket 60 is disposed in the head body 41 while avoiding the plug hole wall 91, the intake port wall 101, the exhaust port wall 102, the boss 103, and the like. That is, a part of each wall is provided in the head side water jacket 60.

  Here, partition walls (connection walls) 100 are provided between the adjacent plug hole walls 91 in the head-side water jacket 60 so as to connect them to each other. Each of these partition walls 100 is erected substantially parallel to the cylinder axis over the top and bottom of the head-side water jacket 60, and is integrally formed with the head body 41. By these partition walls 100, the water channel of the head side water jacket 60 is formed between the intake hole side water channel 60a and the exhaust port side water channel 60b between the plug hole wall 91 for the first cylinder and the plug hole wall 91 for the fourth cylinder. (See FIG. 7).

  Further, referring to FIGS. 6 and 7, the cooling water flowing into the head-side water jacket 60 from the intermediate communication port 96d and the left and right front communication ports 96a passes above and below the exhaust port wall 102 of each cylinder 50. While passing, it flows toward the outside in the cylinder row direction while cooling the front of the plug hole 90 and the periphery of the valve seat 74 of the exhaust port 72 (arrow D in the figure). The cooling water that has reached the outside of the first cylinder and the fourth cylinder moves from the exhaust port side water passage 60b to the intake port side water passage 60a, passes through the upper and lower sides of the intake port wall 101 of each cylinder 50, and plug hole 90 Flows inward in the cylinder row direction while cooling the rear and the periphery of the valve seat 73 of the intake port 71 (arrow E in the figure). Then, the cooling water flows out of the head side water jacket 60 from the cooling water outlet 61 provided behind the second cylinder and the third cylinder (arrow F in the figure), and is directly attached to the cooling water outlet 61. Sent to the thermostat 62 (see FIG. 2 or 3).

  The partition wall 100a provided between the second cylinder and the third cylinder is formed in a slightly convex arc shape on the intake port 71 side due to the flow pattern of the cooling water. Further, a partition wall 100b provided between the first cylinder and the second cylinder and between the third cylinder and the fourth cylinder is formed in a convex shape on the exhaust port 72 side, and is upstream of the head side water jacket 60. This prevents the vortex or the like of the cooling water from being generated in the exhaust port side water passage 60b that is on the side and has a relatively high flow velocity. Note that bosses 105 for fixing the breather chamber 104 provided above the head cover 42 are provided at both ends of the partition wall 100b.

  Further, each partition wall 100 is provided with an air vent hole (not shown) for preventing air accumulation in the upper portion thereof, and the air reservoir around the partition wall 100 whose flow diameter largely changes with respect to the periphery of the plug hole wall 91. In addition, since a part of the cooling water flows from the exhaust port side water channel 60b to the intake port side water channel 60a from the air vent hole, it is possible to effectively prevent the stagnation of the cooling water around the partition wall 100. The flow rate of the cooling water flowing from the air vent hole to the intake port side water channel 60a is sufficiently small relative to the flow rate of the cooling water flowing from the outside of the first cylinder and the fourth cylinder to the intake port side water channel 60a. The flow of cooling water in the side water jacket 60 is maintained in the flow shown in FIG.

  As shown in FIGS. 3 and 4, four cylinders 50 are formed in the cylinder block 43 side by side in the vehicle body width direction. Further, pistons 51 are slidably fitted in these cylinders 50. A connecting rod 53 is rotatably connected to each piston 51 via a crank pin 54, and a large end portion of the connecting rod 53 is rotatably connected to a crank pin 54 of a crankshaft 47, and the reciprocating motion of the piston 51 is an axis. It is converted into a rotational motion around C.

  Further, in the crankcase 31, a crankshaft 47 is disposed on the front side with an axis C parallel to the vehicle body width direction, and a clutch mechanism 163 and a transmission 164 are disposed on the rear side. A starter motor 107 including a starter motor 107 and a starter gear group 108 meshing with the starter motor 107 is disposed above the transmission 164 so that the crankshaft 47 can be rotated when the engine is started (FIG. 4).

  An oil pump 89 that pumps the engine oil L to an appropriate location in the engine 15 is disposed below the crankcase 31. The oil pump 89 is linked to the oil pump drive sprocket 128 that rotates together with the main shaft 192 of the transmission 164 via the chain 129, and starts to operate as the crankshaft 47 rotates. Engine oil L is stored in an oil pan 46 fixed to the lower portion of the lower case 45, and an oil strainer 130 is immersed in the stored engine oil L.

  The upper end of the oil strainer 130 is connected to the suction port of the oil pump 89, and the discharge port of the oil pump 89 is connected to a first oil passage 133 formed in the lower case 45. The first oil passage 133 extends upward from the discharge port of the oil pump 89 and then bends forward, extending slightly forward and extending forward. A cartridge type oil filter 134 is detachably attached to the front wall 196 of the lower case 45. The oil filter 134 can be detached from the side of the engine 15. The engine oil L flows into the oil filter 134 from the oil inflow path 136, flows out of the oil outflow path 137, and is guided to the water-cooled oil cooler 65.

  The water-cooled oil cooler 65 is attached to the front portion of the lower case 45 that constitutes the crankcase 31, and cools the engine oil L flowing through the interior thereof with cooling water. The cooling water is introduced from an introduction hose 68 attached to the oil pump 89. Cooling water after cooling the engine oil L by flowing through the water-cooled oil cooler 65 is returned to the water pump 55 via the outlet hose 67.

The outlet of the water-cooled oil cooler 65 is connected to a second oil passage 140 that is formed in the lower case 45 and slightly rises rearward and extends rearward substantially in parallel with the first oil passage 133. The second oil passage 140 leads to the main oil gallery 173 and the like in the engine 15.
The engine oil L supplied to the engine 15 returns to the oil pan 46 and is stored by natural dripping or the like. The engine oil L is supplied to the engine 15 again through the oil strainer 130, the oil pump 89, the oil filter 134, and the water-cooled oil cooler 65, and repeatedly circulates in the engine 15. In the circulation of the engine oil L, for example, when the engine 15 is at a high rotation speed and the oil pressure of the engine oil L reaches a predetermined value, the first oil passage 133 and the oil inflow passage 136 are below the intersection. The oil relief valve 142 connected via the relief path 141 operates. A part of the engine oil L flows back into the oil pan 46, and the hydraulic pressure in the path is adjusted.

  A water pump 55 that circulates cooling water is attached to the right side wall 43 a of the cylinder block 43 of the engine 15. The position of the water pump 55 is between the cylinder center line SC, which is the central axis of the cylinder 50, and the transmission 163, and partially overlaps the cylinder 50 in the front-rear direction in the vicinity of the cylinder 50 of the cylinder block 43 and in a side view. Position. A cooling water introducing hose 58 for introducing cooling water from the radiator 36 and a bypass hose 64 are connected to the water pump 55 (see FIG. 2). The cooling water pumped from the water pump 55 with the rotation of the crankshaft 47 flows into the cylinder-side water jacket 57 from a cooling water inlet (not shown) provided on the right side of the cylinder block 43, and the head side at the rear of the cylinder head 40. It flows out from the cooling water outlet 61 provided in the water jacket 60. A part of the cooling water to be pumped is supplied to the water-cooled oil cooler 65 through the introduction hose 68.

  The arrangement and structure of the water pump will be described in more detail with reference to FIG. 8 is a cross-sectional view taken along the line AA in FIG. A crankshaft 47 is disposed in the crankcase 31, and a transmission 164 including a shift drum 123 is provided at the rear stage of the crankcase 31. The above-described water-cooled oil cooler 65 is disposed substantially at the center of the front wall 196 of the crankcase 31, and an oil filter 134 is attached to the right side of the water-cooled oil cooler 65. A water pump drive sprocket 147 and a camshaft drive sprocket 149 for rotating the camshafts 85 and 86 are arranged in this order from the inner side in the vehicle width direction at the outer end portion 47a of the journal portion 170 at the right end of the crankshaft 47. It is fixed with. Further, a crank pulsar plate 210 having a large number of teeth is attached to the outer side in the vehicle width direction than the camshaft drive sprocket 149, and the rotation speed of the crankshaft 47 is detected by cooperating with a sensor (not shown). It can be done.

  An endless cam chain (not shown) is wound between the camshaft drive sprocket 149 and the camshafts 85 and 86, and the crankcase 31 and the cylinder block 43 have a space (cam The chain room is partitioned. The water pump 55 in the present embodiment is attached to the right outer wall (right wall 43a) of the cylinder block 43 that divides the cam chain chamber, and the water pump body 151 fixed to the right wall 43a has an open end as the water pump. The structure is covered with a pump cover 152.

  The water pump cover 152 has a substantially cylindrical shape with a step, and an introduction pipe 153 that connects the cooling water introduction hose 58 and the bypass hose 64 (both see FIG. 2) extends forward from the substantially center. Yes. When this water pump cover 152 is attached to the water pump body 151 with the cover bolt 154, the space formed therein becomes the pressurizing chamber 155 for pressurizing the cooling water. An O-ring 156 is mounted in the groove on the contact surface of the water pump cover 152.

  A rotation shaft 157 is inserted through the water pump body 151 in parallel with the axis C of the crankshaft 47. The rotating shaft 157 penetrates the cam chain chamber and is pivotally supported by the water pump body 151 and the cylinder block 43 by a bearing 158 or the like. Further, the rotary shaft 157 is provided with a pump driven sprocket 159 that is exposed from the water pump body 151 and reaches the crankcase 31. An endless pump drive chain 148 is wound between the pump driven sprocket 159 and a pump drive sprocket 147 fixed to the right end of the crankshaft 47. When the crankshaft 47 rotates, the rotation shaft 157 rotates.

  The pressurizing chamber 155 is partitioned by the water pump body 151 and the water pump cover 152 and has a rotationally symmetric dome shape with the axis of the rotating shaft 157 as the center. The pressurizing chamber 155 communicates with the introduction pipe 153 at the left end, and has a flow path 155a for flowing the pressurized cooling water toward the rear. The rotating shaft 157 has an end protruding into the pressurizing chamber 155, and an impeller 160 is fixed to the tip of the rotating shaft 157 with a bolt 157a. The impeller 160 has a predetermined clearance from the inner wall of the pressurizing chamber 155. When the rotating shaft 157 rotates, the impeller 160 rotates and the cooling water in the pressurizing chamber 155 is pressurized. A mechanical seal 161 is interposed between the pressurizing chamber 155 and the bearing 158. A flow path 155 a extending from the pressurizing chamber 155 communicates with the discharge chamber 162 at the rear end. The discharge chamber 162 has a shape in which a recess formed in the water pump body 151 is closed by a water pump cover 152 and communicates with a cooling water inlet (not shown) of the cylinder block 43. In addition, an introduction hose 68 for supplying a part of the pumped cooling water to the water-cooled oil cooler is attached to the flow path 155a.

  The crankshaft 47 includes a crank pin 54 that rotatably connects the connecting rod 53 (both see FIG. 3) of the piston 51 along the vehicle body width direction. Since the engine 15 is an in-line four-cylinder type, the crankshaft 47 includes four crankpins 54. Each crank pin 54 is supported by a pair of crank arms 169. Each crank arm 169 is integrally formed with a counterweight 169 a at a portion opposite to the crankpin 54. Five journal portions 170 provided on the axis C between both ends of the crankshaft 47 and the crank arms 169 are rotatably supported by bearings 171 provided in the upper case 44 and the lower case 45. A generator serving as a starter and charger is disposed at the left end of the crankshaft 47 and is covered with a generator cover 126.

  In addition, a secondary balancer 185 is disposed at the front portion of the crankcase 31 and slightly to the left of the vehicle width direction central portion. The secondary balancer 185 is housed in a housing portion 186 formed by a part of the lower case 45 bulging forward. A balancer drive gear 187 for rotating the secondary balancer 185 is provided on the outer peripheral portion of the left crank arm 169 supporting the second crank pin 54 from the left side and the counterweight 169a formed integrally therewith.

  A primary drive gear 189 is provided on the outer periphery of the left crank arm 169 that supports the rightmost crank pin 54 and the counterweight 169a that is integrally formed therewith, and this primary drive gear 189 is arranged on the right side of the crankcase 31. It meshes with the primary driven gear 190 of the clutch mechanism 163 provided. The clutch mechanism 163 includes a primary driven gear 190, a clutch outer 191 that rotates integrally therewith, a clutch center 193 that is housed in the clutch outer 191 and rotates integrally with the main shaft 192 of the transmission 164, the clutch outer 191 side, A plurality of friction plates 191a, 193a,... On the clutch center 193 side are provided.

  A pressure plate 195 urged by a plurality of clutch springs 194 is attached to the clutch center 193, and the friction plates 191a... 193a. It becomes a state that can be transmitted. On the other hand, when the shift drum 123 is operated, the clutch release 200 disposed on the left side of the crankcase 31 is operated, and the pressure plate 195 is attached to the clutch spring 194 via the rod 197 inserted into the main shaft 192. Moved against power. As a result, the friction plates 191a, 193a,... Are separated from each other, and the power transmission by the clutch mechanism 163 is cut off.

The transmission 164 is arranged in parallel with the axis C, and is rotatably supported by the crankcase 31. The counter shaft 198 (both are spline shafts) shown in FIG. And a shift drum 123 and a shift fork 124 for controlling the meshing gears of the transmission gear group 199. The main shaft 192 is coaxially arranged with the clutch mechanism 163, and the clutch center 193 of the clutch mechanism 163 is fitted and fixed to the right end portion of the main shaft 192. The shift fork 124 has one end engaged with a groove formed on the outer periphery of the shift drum 123 and the other end engaged with a specific gear of the transmission gear group 199. 8 shows only the shift fork 124 engaged with the main shaft 192 side, the transmission 164 also includes a shift fork engaged with the counter shaft 198 side. When the gear position is switched, the shift drum 123 is rotated by the driver's operation, and the shift fork 124 slides in the width direction of the engine 15 along with this, and the specific gears constituting the transmission gear group 199 are slid. To engage the gear or to disengage the gear.
The driving force generated by the engine 15 is transmitted from the crankshaft 47 to the main shaft 192 of the transmission 164 via the primary drive gear 189, the primary driven gear 190, and the clutch mechanism 163, and via the transmission gear group 199. It is transmitted to the countershaft 198 at a predetermined gear ratio, and further transmitted from the drive sprocket 27 (see FIG. 1) fixed to the left end portion of the countershaft 198 to the rear wheel 7 via the drive chain 28.

  Reference numerals 172, 173, 174, 175, 176, and 177 denote paths of the engine oil L. The oil groove 172 is formed at a substantially central portion in the axis C direction on a receiving surface that supports the peripheral surface of the journal portion 170 in each bearing 171. The main oil gallery 173 is formed in the lower case 45 in the vehicle body width direction over the vicinity of both ends of the crankshaft 47. The oil path 174 connects the main oil gallery 173 and the oil groove 172 of each bearing 171. Engine oil L is supplied from the main oil gallery 173 to the bearings 171 via the oil path 174 and the oil groove 172. The oil holes 175 penetrate the portions of the four journal portions 170 except the rightmost side facing the oil groove 172 of the bearing 171 in the radial direction. The oil hole 176 penetrates substantially the center portion in the axial direction of the crank pin 54 in the radial direction. The communication oil hole 177 is formed in the crankshaft 47 and allows the oil hole 175 and the oil hole 176 to communicate with each other. A part of the engine oil L supplied to the oil groove 172 through the oil hole 175, the communication oil hole 177, and the oil hole 176 is supplied to the peripheral surface of each crank pin 54. The opening of the communication oil hole 177 formed in the crank arm 169 is closed by press-fitting a steel ball or the like.

  The main shaft 192 and the countershaft 198 of the transmission 164 shown in FIG. 4 are both hollow bodies, and the engine oil L flows through the hollow portions through the oil holes or the like to the sliding surfaces, the transmission gear group 199 (FIG. 8). Engine oil L is supplied to the clutch mechanism 163 and the like. Similarly, the camshafts 85 and 86 shown in FIG. 4 are also made of a hollow body, and the engine oil L flows through the hollow portions and the engine oil L is supplied to the sliding surfaces from the oil holes or the like.

  When the engine 15 starts, the crankshaft 47 rotates and the rear wheel 7 rotates via the transmission 163. When the crankshaft 47 rotates, the driving sprocket 147 also rotates, and the pump driving chain 148 rotates.

  As shown in FIG. 8, in this embodiment, the water pump driving sprocket 159 for driving the water pump 55 is arranged on the inner side in the vehicle width direction of the camshaft driving sprocket 149 of the crankshaft 47 (on the axis C of the crankshaft 47). (Inward direction). Therefore, the water pump 55 can be arranged closer to the center of the engine 15 than in the case where the rotating shaft of the water pump is directly connected to the camshaft or the crankshaft as in a general water pump. For this reason, the width of the engine 15 in the vehicle width direction can be reduced, the engine 15 can be downsized, and the turning performance of the vehicle can be improved.

  Further, as shown in FIG. 4, in this embodiment, a water pump 55 is disposed in the vicinity of the cylinder 50 of the engine 15. Alternatively, since the water pump 55 is disposed at a position overlapping the cylinder 50 in a side view, the turning performance of the vehicle can be improved. Furthermore, the distance from the discharge side of the water pump 55 to the cylinder-side water jacket 57 formed in the cylinder block 43 can be shortened. The piping can be shortened by that much, and the layout of the cooling water piping becomes easy. And when piping becomes unnecessary, cost reduction becomes possible. In particular, when the water pump 55 is arranged at a position overlapping the cylinder 50 in a side view and between the cylinder center line SC and the transmission 164, the space on the rear side of the cylinder block 43 can be effectively used as the arrangement space. .

  Since the engine 15 includes a circulating water passage in the cylinder head 40 as described with reference to FIGS. 6 and 7, the cooling water flows uniformly in the head-side water jacket 60 to both outsides in the cylinder row direction. As a result, the occurrence of a temperature gradient in the cylinder row direction can be suppressed, and the cylinder head 40 can be cooled evenly. Further, the cooling water flowing in the head-side water jacket 60 can be gathered at one place at the cooling water outlet 61 provided substantially in the center of the cylinder row direction and led out to the outside. Piping can be simplified. Furthermore, by providing an air vent hole in each partition wall 100, it is possible to effectively prevent air accumulation and stagnation around the partition wall 100.

  Further, as shown in FIG. 9, instead of the air vent holes provided in each partition wall 100, a plug for the sand hole (sand plug plug) for closing the sand hole 110 required at the time of casting above each partition wall 100. ) 111 and a gap S between the upper edge of each partition wall 100 and the tip of the plug 111 ensures air accumulation, local boiling, and the like around the partition wall 100 where the flow diameter of the cooling water changes greatly. It is possible to prevent cooling and maintain cooling performance.

  A pair of guide walls 112 and 113 for slidably supporting the valve lifters 79 and 83 of the intake valve 75 and the exhaust valve 76 are provided before and after the four plug hole walls 91 corresponding to each cylinder 50. Between the pair of guide walls 112 and 113 and between the rightmost guide walls 112 and 113 and the cam chain case 114, the journal portions of the intake camshaft 85 and the exhaust camshaft 86 are rotatably supported. Each bearing 87 is provided. An oil groove 88 and an oil path 89 that opens into the oil groove 88 are formed on the sliding surface of the bearing 87 provided between the rightmost guide walls 112 and 113 and the cam chain case 114. Is supplied to the sliding surfaces through the oil grooves 88 and the hollow portions of the camshafts 85 and 86. Bolt holes 87a for fixing bearing caps are formed in front and rear of each bearing 87, respectively.

  As also referring to FIG. 10, a screw hole 116 into which a spark plug 70 inserted into the plug hole 90 is screwed is formed in the bottom wall 115 of the head body 41 that forms the top of each combustion chamber. . Further, an upper partition wall 117 is provided above the bottom wall 115, and a space sandwiched and closed by the upper partition wall 117 and the bottom wall 115 becomes the head-side water jacket 60. Each partition wall 100 is erected from the upper surface of the bottom wall 115 to the lower surface of the upper partition wall 117, and the head side water jacket 60 is separated between adjacent plug hole walls 91.

  Here, in the head main body 41 that is a cast product, the head-side water jacket 60 is formed by setting a core in which exclusive sand is hardened in a molding die, and extracting the core as crushed sand after casting to the outside. However, sand removal holes 110 that are necessary for this purpose are respectively provided in the upper partition walls 117 above the partition walls 100. A part of the upper edge of the partition wall 100 is cut off by each of the sand removal holes 110, and the head side water jacket 60 is opened to the outside to enable sand removal. Then, after sand removal, the plug 111 is screwed into each sand removal hole and closed, thereby allowing cooling water to flow into the head side water jacket 60.

  A pilot portion 118 having a diameter exceeding the thickness of the partition wall 100 is provided at the tip of each plug 111. The front end of the pilot portion 118 has a flat conical shape, and a mortar-shaped matching portion 120 corresponding to the conical portion 119 is formed in the cut portion of each partition wall 100. Further, a gap S is set between the conical portion 119 and the alignment portion 120 in a state in which the plug 111 is screwed into the sand removal hole 110, and one of the cooling water in the exhaust port side water passage 60b is set. The portion can flow from the gap S to the intake port side water passage 60a. The gap S functions in the same way as the air vent hole in the first embodiment, and the occurrence of air accumulation around the partition wall 100 can be suppressed and the occurrence of stagnation of cooling water can be effectively prevented.

  The present invention is not limited to the above-described embodiment. For example, an engine having a plurality of cylinders arranged in the vehicle body width direction may not be an in-line four-cylinder type, and may be a parallel type engine. Furthermore, the present invention is not limited to motorcycles, and can be applied to three-wheel and four-wheel vehicles, ships, and snowmobiles. Moreover, it is not limited to cooling water, Any refrigerant can be used. In this case, the water pump 55 is a pump that pumps the refrigerant.

1 is a side view of a motorcycle according to an embodiment of the present invention. It is a side view of the engine periphery. It is a left view of an engine. It is a right view of an engine. It is side surface explanatory drawing of a head main body. It is sectional drawing which follows the BB line of FIG. It is explanatory drawing of the head side water jacket in FIG. It is sectional drawing which follows the AA line of FIG. It is a top view of a head body. It is sectional drawing which follows the CC line of FIG.

Explanation of symbols

15 Engine (Internal combustion engine)
47 Crankshaft 47a End (one end)
50 Cylinder 55 Water Pump 85 Intake Side Camshaft 86 Exhaust Side Camshaft 147 Water Pump Drive Sprocket 148 Pump Drive Chain (Chain)
149 Camshaft Drive Sprocket 159 Water Pump Drive Sprocket C Axis SC Cylinder Centerline (Centerline)

Claims (3)

In the internal combustion engine provided with a camshaft drive sprocket for driving the camshaft at one end of the crankshaft,
The camshaft driving sprocket and the water pump driving sprocket are arranged on the crankshaft, the water pump driving sprocket is arranged inside the axial direction of the crankshaft, and the camshaft driving sprocket is driven by the water pump. An internal combustion engine characterized in that a water pump for circulating cooling water is driven by a chain that is arranged outside the sprocket for use and wound around the sprocket for driving the water pump.   The internal combustion engine according to claim 1, wherein the water pump is disposed near a cylinder. 2. The internal combustion engine according to claim 1, wherein the water pump is arranged behind the center line of the cylinder and at a position overlapping the cylinder in a side view.

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