JP2017145788A - Auxiliary machine mounting structure of power unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an auxiliary machine mounting structure of a power unit in which, even when mounting an auxiliary machine having a driven shaft which is connected to a cylinder head by a coaxial line with a camshaft and rotates, the cam shaft can be removed without removing the auxiliary machine, and a valve drive member can be removed.SOLUTION: The present invention relates to the auxiliary machine mounting structure of a power unit 1, including an auxiliary machine 8 having a driven shaft 81 which is provided in one end side of a camshaft 41 supported by a cylinder head 23 and is connected by the coaxial line and rotate, and including a valve drive member 74 which is pushed and driven by a cam crest 45 in the one end side of the camshaft, and having a linear groove 41a in a direction perpendicular to the axis S at the shaft end in one end side of the cam shaft. In the driven shaft, a linear rib 81a fitted to the linear groove is provided so as to protrude, and the linear rib is provided with a relief part 81b for allowing the valve drive member to pass in the central part including an axis P of the driven shaft.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an auxiliary machine mounting structure when an auxiliary machine of a power unit is mounted to a cylinder head.

  In the conventional power unit, in which the water pump is attached to the cylinder head, for example, as shown in Patent Document 1 below, the water pump shaft is inserted into the joint member fitted to the camshaft, and assembled. When the camshaft is removed, the inserted water pump shaft must be removed, and it has been desired to improve the workability of maintenance, such as replacement of a tappet shim that requires removal of the camshaft.

JP 2014-070499 A (FIGS. 1 to 5)

  The present invention has been made in view of such a conventional technique, and even when an auxiliary machine having a driven shaft that rotates by being connected to a camshaft and a coaxial line is attached to a cylinder head, the cam can be removed without removing the auxiliary machine. It is an object of the present invention to provide a power unit auxiliary machine mounting structure that can remove the shaft, can perform the detaching and mounting operation of the valve drive member, has good maintainability, and can reduce the size of the power unit.

In order to solve the above-described problems, the invention according to claim 1 is characterized in that a cylinder head, a head cover covering the cylinder head, a cam shaft supported by the cylinder head, provided on one end side of the cam shaft, and connected to the cam shaft by a coaxial line. In a power unit accessory mounting structure comprising an auxiliary machine having a driven shaft that rotates in rotation, and a valve drive member that is driven by a cam crest on the one end side of the camshaft, the shaft on the one end side of the camshaft A linear groove for driving the auxiliary machine in a direction perpendicular to the axis of the camshaft is provided at the end, and the driven shaft on the auxiliary machine side is provided with a linear rib that fits the linear groove, and the straight line The rib has a power unit accessory mounting structure characterized in that a relief portion for allowing the valve drive member to pass therethrough is provided at a central portion including the axis of the driven shaft.

  According to a second aspect of the present invention, in the auxiliary unit mounting structure of the power unit according to the first aspect, the valve driving member is a valve lifter of an intake valve or an exhaust valve provided in the cylinder head. A shim member is provided between the stem end of the intake valve or the exhaust valve.

  According to a third aspect of the present invention, in the auxiliary unit mounting structure for a power unit according to the second aspect, the power unit includes a plurality of cylinder axis lines arranged in the crankshaft direction, and an intake camshaft on the cylinder head parallel to the crankshaft. And an in-line multi-cylinder DOHC type internal combustion engine having an exhaust camshaft, the auxiliary machine is a water pump device, and the water pump device is provided on the one end side of the intake camshaft. And

  According to a fourth aspect of the present invention, in the auxiliary unit mounting structure of the power unit according to the third aspect, the intake system parts of the internal combustion engine include a throttle valve of a throttle device and a throttle drive motor that drives the throttle valve. The drive system member for transmitting the power of the throttle drive motor to the throttle valve is provided close to the water pump device.

  According to a fifth aspect of the present invention, in the auxiliary unit mounting structure of the power unit according to the fourth aspect, the water pump device includes an impeller chamber, and cooling from the impeller chamber to a cooling water inlet of the internal combustion engine of the power unit. The pump main body side of the water discharge passage is integrally formed.

  According to a sixth aspect of the present invention, in the auxiliary unit mounting structure for a power unit according to the fifth aspect, the water pump device (8) includes the cooling water discharge passage (86) integrated with the impeller chamber (85). Is assembled to the side surface of the cylinder head (23) by a fastener (91).

  According to a seventh aspect of the present invention, in the auxiliary unit mounting structure for a power unit according to any one of the first to sixth aspects, the power unit has two cylinder axes aligned in the crankshaft direction, It is composed of an in-line two-cylinder DOHC internal combustion engine that is 180 degrees out of phase and has an intake camshaft and an exhaust camshaft on the cylinder head in parallel with the crankshaft. And two timing alignment marks are printed on the crankshaft at an interval of 180 degrees as viewed from the auxiliary machine mounting side in the crankshaft direction, and one of the timing alignment marks is at a predetermined position. The linear groove for driving the accessory at the shaft end on one end side of the intake camshaft is provided in the direction of the cylinder axis. Characterized in that it has been.

According to the auxiliary unit mounting structure of the power unit of the first aspect of the present invention, the camshaft is moved along the linear rib of the driven shaft on the auxiliary machine side with the direction of the linear groove being a predetermined vertical direction. Can be removed from the cylinder head without removing the auxiliary machine,
If the driven shaft on the auxiliary machine side is turned to a position where the relief portion of the linear rib passes the valve drive member, the valve drive member can be detached and attached without any trouble due to the linear rib.
The maintainability is improved, and the straight rib can be brought closer to the valve drive member in the axial direction of the camshaft by the escape portion, so that the power unit can be reduced in size.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, in the case where the outer shim member is provided on the top surface of the valve lifter, the outer shim member having a size within the range of contacting the cam crest on the top surface. The size of the surrounding enclosure for mounting is required,
Since the shim member is housed inside the valve lifter, the top surface of the valve lifter may be in the range of contact with the cam crest, and the valve lifter can be miniaturized, contributing to further miniaturization of the power unit. .

According to the invention of claim 3, in addition to the effect of the invention of claim 2, in the water pump device arranged on the intake camshaft side that is close to the intake system component, the maintenance of the shim member of the valve lifter is also performed. Because it is not necessary to remove the water pump device,
It is possible to prevent man-hours and space from being deteriorated due to the removal of the water pump device, and it is possible to contribute to further miniaturization of the power unit by reducing the maintenance space.

  According to the invention of claim 4, in addition to the effect of the invention of claim 3, the drive system member of the throttle device is provided close to the water pump device, so that the throttle drive motor can be brought close to the cylinder head, and maintenance is performed. It is possible to further ensure the performance and reduce the size.

  According to the invention of claim 5, in addition to the effect of the invention of claim 4, it is not necessary to remove the water pump device during maintenance such as replacement of shim members, so the cooling water discharge passage from the water pump device to the internal combustion engine is Since it is integrated with the water pump device instead of a flexible hose when considering the removal of the water pump device, the cooling water discharge passage is compactly formed, the number of parts is reduced, and maintenance is efficient. Well done.

  According to the sixth aspect of the invention, in addition to the effect of the fifth aspect of the invention, it is possible to prevent the water pump device from being removed at the time of camshaft maintenance.

  According to the invention of claim 7, in addition to the effect of the invention of any one of claims 1 to 6, the camshaft removal phase is facilitated by one of the two timing alignment marks provided on the crankshaft. The maintenance of the power unit can be improved.

It is a left view which makes a part of power unit 1 which has an auxiliary machinery attachment structure concerning one embodiment of the present invention a section. FIG. 3 is a right side cross-sectional view above the crankshaft of the power unit shown in FIG. 2. FIG. 3 is a cross-sectional development view of the power unit by combining III-III and III-III ′ in FIG. 2. In FIG. 3, the exhaust side member is not shown because of the relationship in the direction of the arrow, but the reference numeral of the corresponding exhaust side member is added to the reference symbol of the illustrated intake side member with the brackets. Show. The intake camshaft shown in FIG. 2 is extracted and shown in part (a), and in the part (a), a left end view taken along the line bb is shown in part (b). The pump shaft shown in FIG. 2 is extracted and shown in part (a). In part (a), a right end view taken along the line bb is shown in part (b), and in parts (a) and (b). , Cc arrow view is shown in (c) part. FIG. 3 is a top view of a cylinder head in which the head cover and the camshaft holder are removed and the valve lifter is not shown, and the intake camshaft and the pump shaft are indicated by a two-dot chain line. In the combined state, the intake camshaft is removable. FIG. 7 is a top view of the cylinder head taken generally in the direction of arrows VII-VII in FIG. 2. FIG. 6 shows a state where the pump shaft is rotated after the intake camshaft is further removed. The upper end of the valve guide on the intake valve side on the upper surface of the cylinder head and the cylindrical member that houses the valve lifter are shown with the valve lifter removed. The relationship between the crank angle and the protruding state of the cam crest of the intake cam and exhaust cam for each cylinder is shown. ACG rotor wheel and cam-driven sprocket that rotate coaxially with the crankshaft at the first timing T1 with a crank angle of 0 ° or 720 °, an intake-side driven sprocket that is synchronously driven, an intake camshaft, its flange, and an intake cam FIG. 5 is a left side view schematically showing the exhaust side driven sprocket, the exhaust camshaft and the flange portion thereof, the exhaust cam, and the like, and schematically showing the state of the straight groove of the intake camshaft. ACG rotor wheel and cam-driven sprocket that rotate coaxially with the crankshaft at the second timing T2 with a crank angle of 180 degrees, an intake-side driven sprocket that is synchronously driven, an intake camshaft and its flange and intake cam, and exhaust side FIG. 6 is a left side view schematically showing the state of the driven sprocket, the exhaust camshaft and its flange portion and the exhaust cam, etc., together with the state of the straight groove of the intake camshaft.

In the description of the present specification and the claims, the directions such as front, rear, left, right, up and down indicate that the power unit 1 according to this embodiment is mounted on a vehicle (not shown), for example, a motorcycle (motorcycle) in the posture shown in FIG. ) Follow the direction.
In the posture shown in FIG. 1, the left side in the figure is the front of the vehicle, the upper side in the figure is the upper side of the vehicle, the far side in the figure is the right side of the vehicle, and the front side in the figure is the left side of the vehicle.
In the figure, arrow FR indicates the front according to the direction of the vehicle, LH indicates the left side, RH indicates the right side, and UP indicates the upper side.

  FIG. 1 is a left side view, partly in section, of a power unit 1 having an accessory mounting structure according to an embodiment of the present invention. The internal combustion engine 2 constituting the power unit 1 is a water-cooled inline 2-cylinder 4-stroke cycle DOHC internal combustion engine. That is, in the cylinder head valve mechanism, two intake shafts and one exhaust shaft cam shafts 41 and 42 for operating both valve lifters of the in-line two cylinders are provided.

The internal combustion engine 2 according to this embodiment is mounted on a motorcycle with its crankshaft 21 oriented in the vehicle width direction of a motorcycle (not shown) that is a vehicle to be mounted, that is, in the left-right direction.
As shown in FIG. 1, a crankcase 20 that supports a crankshaft 21 that is arranged in the vehicle width direction is divided into upper and lower parts that are divided vertically by a dividing surface 20 a around the crankshaft 21.
A cylinder block 22 having two cylinder bores 22a (see FIG. 3) and a cylinder head 23 are sequentially stacked on the front upper surface of the upper crankcase 20A so that the cylinder axis X is slightly inclined forward and protrudes upward. Then, a head cover 24 is put on the cylinder head 23.

A crankshaft 21 is rotatably held in the vehicle width direction on a split surface 20a between the upper crankcase 20A and the lower crankcase 20B.
On the other hand, an oil pan 25 is attached under the lower crankcase 20B. An oil filter 26 is provided at the front of the lower crankcase 20B.

In the internal combustion engine 2 of the present embodiment, a transmission 5 is incorporated in a crankcase 20 and constitutes a power unit 1.
The crankcase 20 extends rearward from the crankshaft 21, and in addition to the crankshaft 21, includes a main shaft 51, a countershaft 52, and the like of the transmission 5 disposed in the crankcase 20 behind the crankshaft 21. In addition, it is rotatably supported by being oriented parallel to the crankshaft 21 in the vehicle width direction.
As with the crankshaft 21, the main shaft 51 and the countershaft 52 are held on a split surface 20a between the upper crankcase 20A and the lower crankcase 20B via a bearing.

  The transmission 5 is a constantly meshing gear transmission, and a transmission gear group provided on each of the main shaft 51 and the counter shaft 52 meshes with a pair of gears. Switching is performed and a shift is performed.

The rotation of the crankshaft 21 is transmitted to the main shaft 51 via a clutch (not shown) provided at the right end of the main shaft 51, and the counter shaft 52 is shifted by the gear change of the transmission gear group of the transmission 5 to rotate. Is done.
The counter shaft 52 penetrates to the left of the crankcase 20 and protrudes to the outside, and serves as the final output shaft of the power unit 1. The output sprocket 11 is spline fitted to the protruding portion.
Although not shown, a drive chain wound around the output sprocket 11 is laid over a driven sprocket on the rear wheel side, and rotational power is transmitted to the rear wheel.

As shown in FIGS. 2 and 3, the piston 27 sliding in the cylinder bore 22a is connected to the crankpin 21a of the crankshaft 21 via a connecting rod 28 to constitute a crank mechanism.
A combustion chamber 30 is formed in the cylinder head 23 such that a surface facing the top surface of the piston 27 sliding in the cylinder bore 22a is recessed in a dome shape.

  The internal combustion engine 2 of this embodiment is a four-valve internal combustion engine having two intake valves 31 and two exhaust valves 32 per cylinder, and the ceiling surface of the combustion chamber 30 of the cylinder head 23 facing the piston 27 top surface. 30 a is provided with two intake valve ports 33 for opening and closing the intake valve 31 and two exhaust valve ports 34 for opening and closing the exhaust valve 32 (see FIG. 3). The intake valve ports 33 are opened side by side on the almost rear surface, and the exhaust valve ports 34 are opened side by side on the almost front half of the ceiling surface 30a (see FIG. 2).

In the cylinder head 23, the intake port 35 is bent backward from the intake valve port 33, and the exhaust port 36 is bent forward from the exhaust valve port 34 (see FIG. 2).
The intake ports 35 extending rearward from the two intake valve ports 33 arranged side by side for each cylinder are gathered in the collective intake port 35a for each cylinder on the upstream side, and the collective intake port 35a has a throttle. Device 10 is connected.
Further, the exhaust ports 36 extending forward from the two exhaust valve ports 34 arranged on the left and right for each cylinder are gathered in the collective exhaust port 36a for each cylinder on the downstream side. Is connected to an exhaust pipe (not shown).
A spark plug 29 is screwed into the ceiling surface 30a of each combustion chamber 30 in the cylinder head 23 in the vicinity of the cylinder axis X in the center with the tip electrode portion facing the combustion chamber 30 (see FIG. 3).

The intake valve 31 is slidably supported by a valve guide 37 having a valve stem 31 a fitted on the upper wall of the intake port 35, and an umbrella portion 31 b at the tip of the valve stem 31 a opens and closes the intake valve port 33.
Similarly, the exhaust valve 32 is slidably supported by a valve guide 37 fitted to the upper wall of the exhaust port 36, and an umbrella portion 32b at the tip of the valve stem 32a opens and closes the exhaust valve port 34. .

  The valve operating mechanism for driving the intake valve 31 and the exhaust valve 32 is a well-known DOHC type and will not be described in detail, but the intake camshaft 41 and the exhaust camshaft 42 that are parallel to each other and parallel to the crankshaft 21 have flange portions. An intake side driven sprocket 43 and an exhaust side driven sprocket 44 are respectively attached to 41b and 42b, and an endless cam chain 48 is suspended between the cam drive sprocket 47 attached to the crankshaft 21 (see FIG. 3), and rotate in synchronization with each other at a half rotation speed of the crankshaft 21.

  Referring to FIG. 2, when intake camshaft 41 and exhaust camshaft 42 rotate, intake cam 45 provided on intake camshaft 41 and exhaust cam 46 provided on exhaust camshaft 42 The valve lifter 74 is put on the stem end 31c of the valve stem 31b of the valve 31 and the stem end 32c of the valve stem 32a of the exhaust valve 32, respectively, so that the intake valve 31 and the exhaust valve 32 are predetermined according to the rotational position of the crankshaft 21. The intake valve port 33 and the exhaust valve port 34 are opened and closed by reciprocating at this timing.

  A disc-shaped spring seat 70 is fitted to a portion of each valve guide 37 protruding from the upper surface of the cylinder head 23 so as to be perpendicular to the axis of the valve guide 37 and to be in contact with the upper surface of the cylinder head 23. On the other hand, disk-shaped retainers 71 are respectively fixed in the vicinity of the stem ends 31c, 32c of the intake valve 31 and the exhaust valve 32, and a valve spring 72 is contracted between each retainer 71 and the spring seat 70. Yes. As a result, the intake valve 31 and the exhaust valve 32 are always urged upward (the valve closing direction) so that the umbrella portions 31b and 32b block the intake valve port 33 and the exhaust valve port 34, and the intake port 35 and the exhaust port 36 Close the end on the combustion chamber 30 side

A valve lifter 74 is attached to the stem end 31c of the intake valve 31 with a shim member 73 interposed therebetween. The valve lifter 74 is a bottomed cylindrical member including a bottom wall 74a whose outer surface is pressed against the intake cam 45 and a peripheral wall 74b raised downward from the outer peripheral edge of the bottom wall 74a. The end of the stem end 31c of the intake valve 31 is applied to the center of the inner surface of the bottom wall 74a via a shim member 73.
The peripheral wall 74b is slidably fitted to the inner peripheral surface of a cylindrical member 23a provided in the cylinder head 23.
The exhaust valve 31 side is configured similarly to the intake valve 32 side.

As described above, both in the valve lifter 74 as the valve drive member on the intake valve 31 side driven by the intake cam 45 and in the valve lifter 74 as the valve drive member on the exhaust valve 32 side driven by the exhaust cam 46 When the cam crest is pressed, the valve moves downward to open the valve, but the valve lifter 74 is attached to each cam 45, 46 at a position other than the cam crest of each cam 45, 46 of each cam shaft 41, 42, that is, at the base circle of the cam. The valve stems 31a and 32a need to be in a raised position such that the umbrella portions 31a and 32a completely block the intake valve port 33 and the exhaust valve hole 34 by the valve spring 72.
On the other hand, if the distance between the base circle of each cam 45, 46 and the raised position of each valve lifter 74 is too wide, impact and noise will occur when the cam crest contacts.
Therefore, the thickness of the shim member 73 is adjusted and set so as to optimally adjust the distance between the base circle of each cam 45, 46 and the raised position of each valve lifter 74.

However, during operation of the internal combustion engine 2, wear due to sliding contact between the cams 45 and 46 and the valve lifter 74, and contact between the umbrella portions 31 a and 32 a of the valves 31 and 32, the intake valve port 33, and the exhaust valve port 34. Since there is a possibility that the interval may change due to wear or the like due to wear, maintenance is performed such as measuring the interval, so-called tappet clearance measurement, and replacing shim members as necessary.
In that case, since the valve lifter 74 is extracted upward and the shim member 73 is replaced, it is necessary to remove the camshafts 41 and 42 covering the upper portion of the valve lifter 74 before that.

  Generally, the contact between the cam crest and the valve lifter 74 periodically moves. Therefore, when an outer shim member is provided on the top surface of the valve lifter 74, an outer shim member having a size within a range of contacting the cam crest is provided on the top surface. In this embodiment, a shim member 73 is provided between the valve lifter 74 and the stem end 31c, 32c of the intake valve 31 and the exhaust valve 32. Since the shim member 73 is housed inside the valve lifter 74, the top surface of the valve lifter 74 may be in the range of contact with the cam crest, and the valve lifter can be miniaturized, contributing to the miniaturization of the power unit 1. It has become something that can be done.

  By the way, as shown in FIGS. 1 and 3, the power unit 1 of the present embodiment is cooled as an auxiliary machine having a pump shaft 81 serving as a driven shaft that is connected to the cylinder head 23 through a coaxial line and rotates. For example, the water pump device 8 is provided on the left end side of the intake camshaft 41.

  In FIG. 3, a cylindrical projecting portion 83 of a pump main body 80 including a pump shaft 81 and an impeller 82 of the water pump device 8 is fitted into a pump mounting opening 23 b of the cylinder head 23. An impeller chamber 85 on the suction side and a cooling water discharge passage 86 extending on the discharge side to the cooling water inlet 23c on the cylinder head 23 side are integrally formed between the pump cover 84 and the cooling water from the impeller chamber 86. The pump body 80 side of the cooling water discharge passage 86 to the inlet 23c is integrally formed. The cooling water discharge passage 86 communicates with the water cooling jacket 39 on the cylinder head 23 side at the cooling water inlet 23c.

In the water pump device 8, the pump body 80 and the pump cover 84 are fastened to each other by surrounding fastening bolts (“fastener” in the present invention) 91, and a part is fastened to the cylinder head 23 by fastening together.
That is, in the water pump device 8, the cooling water discharge passage 86 integrated with the impeller chamber 85 is assembled on the side surface of the cylinder head 23 by the fastening bolt 91.
For this reason, it is possible to prevent the water pump device 8 from being removed during the maintenance of the intake camshaft 41, so that it is possible to prevent deterioration in maintainability due to outflow of internal cooling water.

As shown in FIG. 1, a main return pipe 88 and a bypass return pipe 89 from a radiator (not shown) are connected to the pump cover 84 of the water pump device 8 and open to the impeller chamber 85 on the suction side.
A cooling water outlet pipe 90 is attached to the cooling water outlet 22B where the water cooling jacket 39 on the cylinder block 22 side is opened, and the cooling water after circulating through the internal combustion engine 2 is sent to a thermostat (not shown).

  The cooling water from the internal combustion engine 2 is sent to the bypass return pipe 89 and returned directly to the water pump device 8 when the cooling water is at a predetermined temperature or lower, such as when the thermostat is started. When the temperature is equal to or higher than the predetermined temperature, the pipe is sent to the radiator through a pipe (not shown), cooled, and then returned to the water pump device 8 through the main return pipe 88.

The intake camshaft 41 and the exhaust camshaft 42 are sandwiched by a camshaft holder 23d fastened from above on the upper side of the cylinder head 23 (see FIG. 2), but are rotatably held as shown in FIG. In addition, an intake side driven sprocket 43 is attached to the right shaft end of the intake camshaft 41 via a flange portion 41 b, and the left shaft end is engaged with the right end of the pump shaft 81 of the water pump device 8.
Although not shown in FIG. 3, an exhaust-side driven sprocket 44 is attached to the right end of the exhaust camshaft 42 via a flange portion 42b (see FIG. 9).

As shown in FIG. 4, a linear groove 41 a for driving the water pump device 8 in the direction perpendicular to the axis S is formed at the left shaft end of the intake camshaft 41.
As shown in FIG. 5, a straight rib 81 a that fits with the straight groove 41 a of the intake camshaft 41 and is perpendicular to the axis P of the pump shaft 81 protrudes from the right end of the pump shaft 81 of the water pump device 8. ing.
Accordingly, when the intake camshaft 41 and the pump shaft 81 are arranged coaxially and the linear rib 81a of the pump shaft 81 is fitted into the linear groove 41a of the intake camshaft 41, the pump shaft is rotated by the rotation of the intake camshaft 41. 81 is driven to rotate.

FIG. 6 shows a cylinder head 23 in which the head cover 24 and the camshaft holder 23d are removed, and the valve lifter 74 is not shown, and the intake camshaft 41 and the pump shaft 81 are indicated by a two-dot chain line in FIG. FIG. 6 is a top view of the intake camshaft 41 in a state where both the shafts 41 and 81 are engaged.
Here, as shown in FIG. 6, when the linear groove 41a of the intake camshaft 41 and the linear rib 81a of the pump shaft 81 are stopped in the vertical direction, preferably in the cylinder axis X direction (see FIG. 2), After removing the camshaft holder 23d, the straight groove 41a is pulled upward along the straight rib 81a to release the engagement between the intake camshaft 41 and the pump shaft 81, and the water pump device 8 is removed from the cylinder head 23. The intake camshaft 41 can be removed without removing it.

FIG. 7 is a top view of the cylinder head 23 as viewed in the direction of arrows VII-VII in FIG. 2, but shows a state in which the pump shaft 81 is rotated after the intake camshaft 41 is further removed in FIG. . Note that the upper end of the valve guide 37 on the intake valve 31 side on the upper surface of the cylinder head 23 and the cylindrical member 23a that houses the valve lifter 74 are shown with the valve lifter 74 removed.
As shown in FIG. 6, the left end side valve lifter 74A (see FIG. 7) that is pressed by the cam crest of the left end side intake cam 45A of the intake cam shaft 41 is accommodated in the left end side cylinder member 23aA. In this state, since it overlaps with the linear rib 81a of the pump shaft 81, there is a possibility that the extraction may be hindered, but in this embodiment, the problem is solved by the structure shown in FIGS.

That is, the linear rib 81a of the pump shaft 81 includes an escape portion 81b through which the valve lifter 74A on the left end side passes at the center including the axis P of the pump shaft 81, as shown in FIGS.
In other words, the straight rib 81a has a protrusion extending linearly perpendicular to the axis P of the pump shaft 81, leaving only the outer peripheral side of the pump shaft 81 around the axis P of the pump shaft 81 as a relief portion 81b. As shown in FIG. 7, after removing the intake camshaft 41, the pump shaft 81 is arranged so that the straight rib 81a is substantially perpendicular to the extraction direction of the valve lifter 74A on the left end side. 7A and 7B, the valve lifter 74A can be extracted without being caught by the straight rib 81a through the escape portion 81b, as particularly shown by the two-dot chain line in FIG.

Thus, the intake camshaft 41 is moved along the linear rib 81a of the pump shaft 81 on the water pump device 8 side with the direction of the linear groove 41a being a predetermined vertical direction, preferably the cylinder axis X direction. Thus, the water pump device 8 can be removed from the cylinder head 23 without removing it, and the pump shaft 81 on the water pump device 8 side is rotated by the relief portion 81b of the linear rib 81a passing the valve lifter 74A on the left end side. If it is in the position, the valve lifter 74A can be removed and attached without hindrance by the straight rib 81a, and the ease of maintenance such as replacement of the shim member 73 is improved.
Further, the linear rib 81a can be brought close to the valve lifter 74A in the direction of the axis S of the intake camshaft 41, that is, the direction of the axis P of the pump shaft 81 by the escape portion 81b, and the power unit 1 can be miniaturized.

The power unit 1 of the present embodiment includes two cylinders in which two cylinder axis lines X are arranged in the direction of the crankshaft 21 (referred to as a first cylinder C1 and a second cylinder C2), and the phases of the crankpins 21a are mutually 180 degrees. The in-line two-cylinder DOHC type internal combustion engine 2 having an intake camshaft 41 and an exhaust camshaft 42 parallel to the crankshaft 21 on the cylinder head 23 is configured.
Therefore, as shown in FIG. 8, the relationship between the crank angle and the protruding state of the cam crest of the intake cam 45 and the exhaust cam 46 for each cylinder is synchronized in accordance with the crank angle in the first cylinder C1 and the second cylinder C2. The cam peaks of the intake cam 45 and the exhaust cam 46 corresponding to each protrude toward the corresponding valve lifter 74. (In FIG. 8, the protruding direction of the cam crest is shown upward, but actually protrudes downward toward the valve lifter 74.)
The period of the crank angle where each cam mountain does not protrude is a period corresponding to the base circle of each cam mountain.

The clearance (so-called tappet clearance) between the base circle of each cam crest and the upper limit position of the valve lifter 74 is measured, and the camshafts 41 and 42 are removed in the exhaust camshaft 42 in the first cylinder C1. The second cylinder C2 is a period in which the cam crest of the exhaust cam 46 does not protrude toward the valve lifter 74, the illustrated crank angle is in the range of CA1, and the most preferable crank angle is 720 degrees (or 0 degrees). This time is defined as a first timing T1.
In the intake camshaft 41, both the first cylinder C1 and the second cylinder C2 are periods in which there is no protrusion of the cam crest of the intake cam 45 toward the valve lifter 74, and the illustrated crank angle is in the range of CA2, which is most preferable. This is when the crank angle is 180 degrees with respect to the crank angle of 720 degrees (or 0 degrees) at the first timing T1, and this time is defined as the second timing T2.

  Choosing a base circle with no cam peaks protruding toward the valve lifter 74 of each cam is essential for measuring tappet clearance, and cam cams are This is to avoid a repulsive force acting on the camshafts 41 and 42 when the camshafts 41 and 42 are removed while protruding and the valve lifter 74 is pushed down.

Therefore, in this embodiment, in the maintenance work such as the tappet clearance measurement and the replacement of the shim member 73, the exhaust camshaft 42 side is performed at the first timing T1 (crank angle 0 degree or 720 degrees), and the intake cam The shaft 41 side is performed at the second timing T2 (crank angle 180 degrees), and the crankshaft 21 has the first and second timing alignment marks in accordance with the states of the first and second timings T1 and T2. Two locations are printed at intervals of 180 degrees so that T and 2T are detected at predetermined detection locations.
Specifically, the first and second timing alignment marks T and 2T are imprinted on the outer peripheral edge 16a of the rotor wheel 16 of the AC generator (ACG) 15 that is coaxial with the crankshaft 21 and rotates in the same direction. This is the same as that printed on the crankshaft 21.
Further, as a predetermined detection location, visual detection is performed from a viewing window 17b that is opened in the ACG cover 17 and normally closed by a plug 17a.

  Since the first and second timing alignment marks T and 2T each indicate one place in the range of 720 degrees of the crank angle, T1 is at the crank angle of 360 degrees, and T2 is at the crank angle of 540 degrees from the viewing window 17b. As shown in FIG. 8, the exhaust cam 46 is slightly protruded at both the first cylinder C1 and the second cylinder C2 at a crank angle of 360 degrees, and at the crank angle of 540 degrees, the first cylinder C1 and the first cylinder C1. Since the intake cam 45 is in a slightly protruding state for both the two cylinders C2, it is easily distinguished from the airframe state.

  FIG. 9 shows that the ACG 15 rotor wheel 16 and the cam drive sprocket 47 of the crank shaft 21 and the cam chain 48 of the crank shaft 21 rotate at the first timing T 1 with a crank angle of 0 ° or 720 °. Intake side driven sprocket 43, intake camshaft 41 and its flange portion 41b and intake cam 45, exhaust side driven sprocket 44, exhaust camshaft 42 and its flange portion 42b and exhaust cam 46, which are synchronously driven at a rotational speed of 1/2. FIG. 6 is a left side view schematically showing the above states in a superimposed manner together with the state of the straight groove 41b of the intake camshaft 41.

FIG. 10 shows the rotor wheel 16 and the crankshaft 21 of the ACG 15 rotating coaxially with the crankshaft 21 at the second timing T2 when the crank angle is 180 degrees, that is, the camshafts 41 and 42 are rotated 90 degrees from the state of FIG. Cam driven sprocket 47, intake side driven sprocket 43 that is synchronously driven by the cam chain 48 at half the rotational speed of the crankshaft 21, intake camshaft 41 and its flange 41b and intake cam 45, exhaust side driven sprocket 44 is a left side view schematically showing the states of the exhaust camshaft 42 and its flange portion 42b and the exhaust cam 46, etc., together with the state of the straight groove 41b of the intake camshaft 41. FIG.
9 and 10, the position of the valve lifter 74 and the gap gauge 18 are only shown to show the measurement of the tappet clearance, and are different from the actual form and size.

In FIG. 9, the state is the first timing T 1, and the first timing alignment mark T stamped on the rotor wheel 16 of the AC generator (ACG) 15 is visually detected from the viewing window 17 b of the ACG cover 17. .
The cam crest of the exhaust cam 46 of the exhaust cam shaft 42 is not projected toward the valve lifter 74, and the tappet clearance of the exhaust cam shaft 42 is measured.
Further, since the water pump device 8 is not attached to the exhaust camshaft 42 and the cam crest of the exhaust cam 46 is not in a protruding state, maintenance such as removal of the exhaust camshaft 42 and replacement of the shim member 73 can be performed. .

  An imaginary line 41ba shown at the center of the flange portion 41b of the intake camshaft 41 indicates the direction of the linear groove 41a provided on the shaft end opposite to the flange portion 41b, and the first timing alignment mark T is displayed from the viewing window 17b. At the first timing T1 that is detected visually, the straight groove 41a does not face in the vertical direction, so the intake camshaft 41 cannot be removed.

In FIG. 10, it is in the state of the second timing T2, and the second timing alignment mark 2T stamped on the rotor wheel 16 of the AC generator (ACG) 15 is visually detected from the viewing window 17b of the ACG cover 17. .
The cam crest of the intake cam 45 of the intake camshaft 41 is not projected toward the valve lifter 74, and the tappet clearance of the intake camshaft 41 is measured.
Further, as indicated by a virtual line 41ba at the center of the flange portion 41b of the intake camshaft 41, a straight groove 41a provided at the left shaft end of the intake camshaft 41 is drawn out at the upper right in the drawing, It faces in the direction of the axis X, and after removing the camshaft holder 23d (see FIGS. 2 and 3), the linear groove 41a is fitted upward along the linear rib 81a of the pump shaft 81 fitted into the linear groove 41a. By pulling out, it is possible to remove the intake camshaft 41 without releasing the engagement between the intake camshaft 41 and the pump shaft 81 and detaching the water pump device 8 from the cylinder head 23. Maintenance can be performed.

  As described above, the water pump device 8 as an auxiliary device is provided on the left end side of the intake camshaft 41, and each camshaft for maintenance is viewed in the direction of the crankshaft 21 when viewed from the water pump device 8 mounting side, that is, the left side. In order to detect the positions of 41 and 42, the first and second timing alignment marks T and 2T are provided at two 180 ° intervals on the rotor wheel 16 of the AC generator (ACG) 15 that rotates coaxially with the crankshaft 21. When one of the timing alignment marks 2T is printed, and the linear groove 41a for driving the water pump device 8 at the left end of the intake camshaft 41 is in the direction of the cylinder axis X. Since it is provided, the intake camshaft 41 to which the water pump device 8 is attached is attached by one of the two timing alignment marks for maintenance 2T. To be phase easily determine, it has improved maintainability of the power unit.

  In the above embodiment, the water pump device 8 as an auxiliary machine is provided on the left end side of the intake camshaft 41, but the intake camshaft is close to the intake system components such as the throttle device 10 and the like. Even in the case of the water pump device 8 arranged on the 41 side, it is not necessary to remove the water pump device 8 at the time of maintenance of the shim member 73 of the valve lifter 74. A decrease in maintainability can be prevented, and a reduction in maintenance space can contribute to further miniaturization of the power unit 1.

  As shown in FIGS. 1 and 2, the throttle device 10 as an intake system component is connected to the collective intake port 35a, and has a throttle valve 101, a throttle drive motor 102 for driving the throttle valve 101, and a throttle drive. A drive system member 103 for transmitting the power of the motor 102 to the throttle valve 101 is provided.

  The drive system member 103 includes a drive unit case 104 formed integrally with the throttle device 10 and an output pinion 102a of the throttle drive motor 102 housed in the motor housing portion 105 to the valve shaft 101a of the throttle valve 101. The drive unit case 104 is provided with a speed reduction mechanism 106 that transmits the speed between them, and the drive system member 103 is provided close to the water pump device 8, so that the throttle drive motor 102 is brought closer to the cylinder head 23. Therefore, it is possible to further ensure the maintainability and reduce the size.

Further, in this embodiment, the water pump device 8 includes an impeller chamber 85, and the pump body 80 side of the cooling water discharge passage 86 from the impeller chamber 85 to the cooling water inlet 23c of the internal combustion engine 2 of the power unit 1 is integrally formed. Is formed.
That is, since it is not necessary to remove the water pump device 8 at the time of maintenance such as replacement of the shim member 73, the cooling water discharge passage 86 from the water pump device 8 to the internal combustion engine 2 can be provided in consideration of removal of the water pump device 8. There is no need for a flexible hose, and it can be integrated with the water pump device 8, and the cooling water discharge passage 86 can be formed compactly, reducing the number of parts and performing maintenance efficiently. Yes.

  Further, in this embodiment, the water pump device 8 has the cooling water discharge passage 86 integrated with the impeller chamber 85 assembled on the side surface of the cylinder head 23 by the fastening bolt 91, so that the water during the maintenance of the intake camshaft 41 is maintained. Since it is possible to prevent the pump device 8 from being removed, it is possible to prevent deterioration in maintainability due to outflow of cooling water.

The power unit accessory mounting structure of the embodiment according to the present invention has been described above, but the aspect of the present invention is not limited to the above embodiment, and can be implemented in various aspects within the scope of the claims of the present invention. Of course, it is included.
Further, the arrangement of the left and right of each device has been described specifically for the convenience of description of the embodiment, but may be an arrangement that is opposite to the one shown in the above embodiment. include.

  DESCRIPTION OF SYMBOLS 1 ... Power unit, 2 ... Internal combustion engine, 8 ... Water pump apparatus, 10 ... Throttle apparatus, 15 ... Alternator (ACG), 17b ... Viewing window, 16 ... Rotor wheel, 18 ... Crevice gauge, 20 ... Crankcase, 21 ... Crankshaft, 21a ... Crank pin, 22 ... Cylinder block, 22b ... Cooling water outlet, 23 ... Cylinder head, 23a ... Cylinder member, 23b ... Pump mounting opening, 23c ... Cooling water inlet, 23d ... Camshaft holder, 24 ... Head cover, 27 ... piston, 30 ... combustion chamber, 31 ... intake valve, 31a ... valve stem, 31c ... stem end, 32 ... exhaust valve, 32a ... valve stem, 32c ... stem end, 35 ... intake port, 36 ... exhaust port 37 ... Valve guide, 41 ... Intake camshaft, 41a ... Linear groove, 42 ... Exhaust camshaft, 43 ... Intake side driven sprocket, 44 ... Exhaust side driven sprocket, 45 ... Intake cam, 46 ... Exhaust 47, cam drive sprocket, 48 ... cam chain, 73 ... shim member, 74 ... valve lifter, 80 ... pump body, 81 ... pump shaft, 81a ... linear rib, 81b ... relief, 82 ... impeller, 85 ... impeller chamber 86 ... Cooling water discharge passage, 91 ... Fastening bolt ("fastener" in the present invention), 101 ... Throttle valve, 102 ... Throttle drive motor, 103 ... Drive system member, 106 ... Deceleration mechanism, X ... Cylinder axis, S ... Axis (of intake camshaft 41), P ... Axis of (pump shaft 81), T ... first timing alignment mark, 2T ... second timing alignment mark

Claims (7)

A cylinder head (23) and a head cover (24) covering it,
An auxiliary machine (8) having a driven shaft (81) provided on one end side of a camshaft (41) supported by the cylinder head (23) and connected to the camshaft (41) through a coaxial line and rotated;
In the auxiliary equipment mounting structure of the power unit (1) including a valve drive member (74) that is pressed and driven by the cam crest (45) on the one end side of the camshaft (41),
A straight groove (41a) for driving an auxiliary machine (8) perpendicular to the axis (S) of the camshaft (41) at the shaft end on the one end side of the camshaft (41);
The driven shaft (81) on the auxiliary machine (8) side is provided with a linear rib (81a) that fits the linear groove (41a), and the linear rib (81a) is connected to the driven shaft (81a). 81) A power unit accessory mounting structure comprising a relief portion (81b) through which the valve drive member (74) passes at a central portion including the axis (P) of 81).   The valve drive member (74) is a valve lifter (74) of an intake valve (31) or an exhaust valve (32) provided in the cylinder head (23). The valve lifter (74) and the intake valve (31) The auxiliary unit mounting structure for a power unit according to claim 1, further comprising a shim member (73) between the stem end (31c, 32c) of the exhaust valve (32). In the power unit (1), a plurality of cylinder axes (X) are arranged in the direction of the crankshaft (21), and the intake camshaft (41) and the exhaust camshaft (41) are parallel to the crankshaft (21) on the cylinder head (23). 42) comprising an in-line multi-cylinder DOHC internal combustion engine (2),
The auxiliary machine (8) is a water pump device (8),
The auxiliary mounting structure for a power unit according to claim 2, wherein the water pump device (8) is provided on the one end side of the intake camshaft (41).   An intake system component of the internal combustion engine (2) includes a throttle valve (101) of a throttle device (10) and a throttle drive motor (102) for driving the throttle valve (101). The power unit accessory mounting structure according to claim 3, wherein a drive system member (103) for transmitting the power of the power unit to the throttle valve (101) is provided close to the water pump device (8). .   The water pump device (8) includes an impeller chamber (85), and a cooling water discharge passage (from the impeller chamber (85) to the cooling water inlet (23c) of the internal combustion engine (2) of the power unit (1)). The auxiliary unit mounting structure for a power unit according to claim 4, wherein the pump body (80) side of 86) is integrally formed.   The water pump device (8) is characterized in that the cooling water discharge passage (86) integrated with the impeller chamber (85) is assembled to a side surface of the cylinder head (23) by a fastener (91). The auxiliary unit mounting structure for a power unit according to claim 5. In the power unit (1), two cylinder axis lines (X) are arranged in the direction of the crankshaft (21), the phases of the crankpins (21a) are shifted from each other by 180 degrees, and the crankshaft (23) is placed on the cylinder head (23). 21) and an in-line two-cylinder DOHC internal combustion engine (2) having an intake camshaft (41) and an exhaust camshaft (42) in parallel.
An auxiliary machine (8) is provided on one end side of the intake camshaft (41),
Two timing alignment marks (T, 2T) are printed at intervals of 180 degrees on the crankshaft (21) when viewed from the side of the auxiliary machine (8) in the direction of the crankshaft (21). When the timing alignment mark (2T) of the intake camshaft (41) is at a predetermined position, the linear groove (81a) for driving the auxiliary machine (8) on the one end side of the intake camshaft (41) is connected to the cylinder axis (X). The auxiliary unit mounting structure for a power unit according to any one of claims 1 to 6, wherein the auxiliary unit mounting structure is provided so as to be in a direction.

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