JPS63131819A - Cooling device for engine - Google Patents

Abstract

PURPOSE:To improve the assemblage property of a cooling water pump housing constituted from housing halves formed respectively integrally with a cylinder block and a cylinder head to be connected to each other. CONSTITUTION:A pair of upper and lower housing halves 155a, 155b are formed respectively integrally with a cylinder block and a cylinder head and connected to each other by bolts 153 to constitute a pump housing 155 of a cooling water pump 154. In the lower housing half 155b are additionally provided an inflow port reaching from the interior an inlet of a water jacket surrounding the cylinder and an inflow pipe 158 opened to the center of the interior of pump housing 155. An impeller 160 of the cooling water pump meshes with a drive gear of a cam shaft 32 to be driven through a pump shaft 161 and a driven gear 164.

Description

Detailed Description of the Invention A0 Objective of the Invention 11) Industrial Field of Application The present invention provides a system in which a pump housing for a water pump is connected to one side of an engine body for supplying cooling water to a water jacket inside the engine body. This invention relates to improvements in cooling systems for engines.

(2) Prior Art Conventionally, there has been known an engine cooling system in which a pump housing is joined to one side of the engine body (see, for example, Japanese Utility Model Application Publication No. 58-186124).

(3) Problems to be solved by the invention According to the above conventional structure, the pump housing must be manufactured separately from the cylinder body, which increases the number of parts and therefore the number of assembly steps, reducing costs. It was difficult to achieve this goal.

The present invention has been made in view of the above circumstances, and enables integral molding of the engine body and the pump housing.
It is an object of the present invention to provide a cooling device that has a small number of parts and is easy to assemble.

B0 Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a pair of cylinder blocks and a cylinder head that are respectively formed integrally with the cylinder block and the cylinder head that constitute the engine body and are joined to each other. The pump housing is characterized in that the pump housing is formed by a housing half.

(2) Effects According to the above configuration, one housing half can be integrally molded with the cylinder block, and the other housing half can be integrally molded with the cylinder head, so there is no need to manufacture the pump housing separately.

Moreover, both housing halves are joined at the same time as the cylinder block and cylinder head are joined.

(3) Examples An embodiment of the present invention will be described below with reference to the drawings.

We will first explain the overall configuration of the engine, and then
The valve train, timing transmission, breather device, clutch, transmission, change mechanism, lubricating device, cooling device, and starting device will be explained in order.

First, in FIGS. 1 to 3, the engine E is for a motorcycle, and the front, rear, left, and right of this engine are based on the vehicle.

The engine body 1 of the engine E includes a cylinder block 3 including four cylinders 2, 2, etc. arranged in series in the left-right direction and tilted slightly forward, and a crankcase 4 integrally connected to the lower end of the cylinder block 3. and cylinder block 3
Between the cylinder head 6 which overlaps the upper end surface and is connected by the port 5, and the cylinder head 6 which overlaps the upper end surface of this cylinder head 6 and is connected to a cam holder 47 (described later) by the port 7, The main elements are a head cover 9 that defines a valve chamber 8 and a mission case 10 that is integrally connected to the rear of the crankcase 4. The cylinder block 3, the crankcase 4, and the transmission case 10 are integrally molded by casting, and the crankcase 4 and the transmission case 10 are cut out at that time.
The right side and lower surface of the engine are open, and the side cover 11 and oil pan 12 are connected to these open ends by ports 13 and 14, respectively.

On the ceiling wall of the crankcase 4, there are crank journal support walls 15. which are vertically connected to the partition walls between the cylinders 2.2 and the outer walls of the cylinders 2.2 located outside the plane.
15... are integrally formed, and the crankshaft 16 housed in the crankcase 4 has a pole (17) attached to these crank journal support walls 15, 15... and their lower ends.
．． It is rotatably held between an integral crank holder 18 connected by 17.... The crankshaft 16 is connected to the cylinder 2
It is connected via connecting rods 20, 20, etc. to the pistons 19, 19, which are connected to the pistons 19, 19, .

Combustion chambers 21, 21, . . . which are connected to the cylinders 2, 2, . The ceiling surface of each combustion chamber 21 is formed in the shape of a mountain with a ridge line parallel to the crankshaft 16, and a pair of intake boats 2 are provided on one slope of the ceiling surface of each combustion chamber 21.
2.22 and the inner ends of a pair of exhaust ports 23.23 on the other slope are opened in parallel along the ridgeline, and the outer end of the intake boat 22.22 is connected to the cylinder head 6.
The outer ends of the exhaust boats 23 and 23 open at the front of the cylinder head 6, respectively.

The spark plug 24 of each combustion chamber 21 is connected to the intake and exhaust boat 22.
, 22; 23, 23, and is screwed onto the cylinder 6.

Intake valves 25 and exhaust valves 26, which open and close each intake boat 22 and exhaust port 23, respectively, are slidably moved up and down by valve guides 27 and 28 fixed to the cylinder head 6, and both valves are moved toward the valve head. 25 and 26 are arranged so that the distance between them is widened.

The suction and exhaust valves 25 and 26 are respectively equipped with valve springs 29 and 30 that bias them in the valve closing direction, and the suction and exhaust valves 25 and 26 resist the force of these valve springs 29 and 30. A valve operating device 31 for opening the valve is provided in the valve operating chamber 8.

The valve train 31 includes an intake camshaft 32 disposed directly above the intake valves 25, 25, . An exhaust camshaft 33 is disposed, and its base end is pivotally supported 34 on the cylinder rod 6, and its free end is connected to the intake camshaft 32 and each intake valve 2.
A rocking type intake cam follower 36 is inserted between the head of each exhaust valve 26 and a rocking type intake cam follower 36 is inserted between the exhaust camshaft 33 and the head of each exhaust valve 26, and the base end is pivotally supported 35 on the cylinder head 6. It consists of a swinging exhaust cam follower 37 whose end is inserted.

At this time, as shown in FIG. 3, the pivot shaft 34 of the intake cam follower 36 is between the intake valve 25 and the spark plug 24, and the pivot shaft 35 of the exhaust cam follower 37 is between the exhaust valve 26 and the exhaust port 23. Placed. In this way,
The intake port 22 can be raised straight from the combustion chamber 21 without being interfered with by the intake cam follower 36, thereby reducing the intake resistance. Sufficient space can be secured for attachment and detachment.

As shown in FIG. 4, a support hole 40 is provided on the lower surface of the free end of each cam follower 36.37, and a protruding shaft is provided on a shim 41 facing the head of the corresponding intake/exhaust valve 25.26. 41a is rotatably fitted into this support hole 40. Therefore, depending on the thickness of the shim 41, the intake and exhaust valves 25.2
The gap between the valve heads 6 is properly adjusted, and the shim 41 is prevented from shifting laterally by fitting the protruding shaft 4fa into the support hole 40.

The intake camshaft 32 includes a plurality of cam journal support walls 42, 42 erected on the bottom wall of the valve chamber 8, and an integral cam holder 44 fixed to these walls with bolts 43, 43
It is rotatably held between the two.

The exhaust camshaft 33 also includes a plurality of cam journal support walls 45, 45 erected on the bottom wall of the valve chamber 8, and an integral cam holder 47 fixed to these with bolts 46, 46. It is rotatably held between the two.

These intake and exhaust camshafts 32 and 33 are connected to the crankshaft 16 via a timing transmission 50.

The timing transmission device 50, as shown in FIGS. 1 and 2,
It is housed in a series of timing transmission chambers 51 formed at the right end of the cylinder block 3, cylinder head 6, and head cover 9, and includes a drive gear 53 fixed to the right end of the crankshaft 16 via a key 52. , a first idle gear 54 that meshes with this drive gear 53, a second idle gear 55 that meshes with this first idle gear 54, and a second idle gear 55 that is substantially fixed to the right end portion of the intake camshaft 32. An intake driven gear 56 that meshes with the exhaust camshaft 33, an exhaust driven gear 57 that is substantially fixed to the right end of the exhaust camshaft 33 and also meshes with the second idle gear 55, and pivotally supports the first and second idle gears 54 and 55. The rotation of the crankshaft 16 is transmitted to both camshafts 32 and 33 at a reduction ratio of 1/2.

The support plate 58 has one end pivotally supported by the crankshaft 16 via a ball bearing 59, and the other end supported by a support shaft 60 screwed onto the cylinder head 6. A pair of upper and lower bosses 61 and 62 are protruded from the right side of the support plate 58, and these are connected to the first and second idle gears 54.
, 55 are supported via ball bearings 63 and 64, respectively.

As shown in FIG. 1A, a predetermined gap 66 is provided between the support shaft 60 and a shaft hole 65 bored in the support plate 58 so as to pass therethrough, and the support plate 58 is
In order to suppress the vibration of the spindle 8, a pair of left and right elastic rings 67 and 67, for example, an O-ring, are attached to the support shaft 60 as a pair of left and right elastic members that are in close contact with the inner surface of the shaft hole 65.

In the illustrated example, the upper post 61 and the shaft hole 65 are arranged concentrically in order to make the support plate 58 more compact, but it is not necessary to do so.

The support shaft 60 has a threaded portion 60a at its tip connected to the timing transmission chamber 51.
The circular head 60b is supported on the outer wall of the enclosure 51 via an O-ring 68, so that it is supported at both ends.

In the above, the engine body 1 is made of Ae alloy, and the support plate 5
8 and drive gear 53 or driven gear 56.57
is said to be made of iron-based materials. Therefore, the engine main body 1 and the timing transmission device M50 have significantly different coefficients of thermal expansion. Furthermore, while the engine E is in operation, the engine body 1 is more strongly influenced by heat than the timing transmission device 50. For this reason, even if the engine main body 1 undergoes a larger thermal expansion than the timing transmission device 50 and the distance between the crankshaft 16 and the support shaft 60 increases, the support shaft 60 will be connected to the axis of the support plate 58 due to the increase. Since the elastic rings 67 and 67 are only moved while being compressed and deformed within the gap 66 between the support plate 58 and the hole 65, the support plate 58 is not affected by the thermal expansion. As a result, not only the distance between the shafts of the first and second idle gears 54 and 55 supported by the support plate 58, but also the distance between the crankshaft 1 supporting one end of the support plate 58 is reduced.
The distance between the shafts of the drive gear 53 and the first idle gear 54 on the gears 53.6 is also not affected by the thermal expansion.
54.55 The backlash between the two camshafts 3 can be kept approximately constant at all times, and the backlash between the two camshafts 3 can be
2.33 can be properly and quietly transmitted.

Note that the thermal expansion of the cylinder head 6 causes the second idle gear 5 to
5 and the intake and exhaust driven gears 56 and 57, but since the distance between their axes is relatively short, the effect is extremely small. However, in the illustrated example, in order to avoid this effect, each driven gear 56
．． 57 is divided into a fixed gear 69 that is substantially fixed to the corresponding camshaft 32, 33, and a movable gear 70 that is connected to this fixed gear 69 via a torsion spring 71. 2nd gear with both gears 69.70 teeth
The teeth of the idle gear 55 are elastically held, thereby constantly eliminating backlash.

Referring again to FIG. 1, the left end of the crankshaft 4 protrudes into the crankcase 4, to which the rotor 48a of the generator 48 is fixed, and the side cover 49 with its stator is fixed to the crankcase 4 with bolts 72.

The breather device will be explained. As shown in FIGS. 1 and 3, a surrounding wall 74 that stands up and surrounds a part of the upper surface of the cam holder 44 on the side of the intake camshaft 32 is integrally formed. Surrounding wall 7
The head cover 9 is abutted against the upper end of 4 with a seal member 76 interposed therebetween.

The pleaser chamber 75 includes a through hole 7 provided in the cam holder 44.
7 to the valve train chamber 8, and also to the air intake system of the engine E or the atmosphere via an air guide pipe 78 attached to the head cover 9.

In this way, when the pleather chamber 75 is defined using a portion of the cam holder 44 and the head cover 9, a dedicated breather chamber body becomes unnecessary, and the structure of the pleather device can be simplified. During operation of the engine E, blow-by gas generated in the crankcase 4 passes through the timing transmission chamber 51 and moves to the valve train chamber 8, and then flows into the pleaser chamber 75 through the through hole 77 and expands. After the oil is separated, it flows out into the air pipe. The separated oil drips into the valve operating chamber 8 from the through hole 77.

The clutch and transmission will be explained. Figures 1 and 5
As shown in the figure, a clutch 8 is installed inside the transmission case 10.
0 and transmission 681 are accommodated.

The input shaft 82 and output shaft 83 of the transmission 81 are the crankshaft 1
6, and a multi-stage transmission gear train 84a to 84n is provided between both shafts 82 and 83.

The left ends of the output shafts 82 and 83 are supported on the left side wall of the mission case 10 via needle bearings 85 and ball bearings 86, respectively, and the right ends are supported on the bulkhead plate 87 in the middle of the mission case 10. They are supported via pole bearings 813 and 89, respectively.

The partition plate 87 has a circular shape and is fitted into an annular step 90 formed on the inner circumferential surface of the mission case 10, and is fitted with a plurality of bosses 91 formed on the circumferential wall of the case 10.
．． 91... with bolts 92, 92... in a removable manner.

The right end of the input shaft 82 extends through the partition plate 87, and the clutch inner 93 of the clutch 80 is fixed to the tip thereof, and the clutch outer 94 is connected to the primary reduction gear 95.
It is connected to the crankshaft 16 via. , the primary reduction gear 95 includes a small-diameter drive gear 96 fixed to the crankshaft 16 and a large-diameter driven gear 97 that is attached to one side of the clutch outer 94 via a torque damper 98 and meshes with the drive gear 96. The driven gear 97 is supported by a spacing tube 99 on the input shaft 82 via a needle bearing 100. In this way, the clutch outer 94 is rotatably supported by the input shaft 82 via the driven gear 97. According to such a configuration, the partition plate 87
Since the transmission 81 can be assembled on the plate 87 before being fixed to the mission case 10, the assemblability is good, and furthermore, the operation of the transmission 81 can be confirmed before being assembled into the mission case 10. It is.

Thus, while the engine E is operating, the output torque of the crankshaft 16 is transmitted to the clutch outer 94 via the drive gear 96 and the driven gear 97, and when the clutch 80 is connected, it is transmitted to the input shaft 82 via the clutch inner 93. Furthermore, the signal is transmitted to the output shaft 83 via one gear train selected from the transmission gear trains 848 to 84n. Output shaft 83
The output torque is transmitted to the rear wheels of the motorcycle via the secondary reduction gear 101 to drive them.

A change mechanism for switching and controlling the transmission 81 will be explained. In FIGS. 5 and 8, the change mechanism 10
4 is a change spindle lO6 equipped with a change pedal 105 as is known, and several cam grooves 107. ~
107. . . , a step feed mechanism 109 that regulates the rotation angle of the change pedal 105 and gives the shift drum 108 a predetermined rotation angle, and one end of which is connected to the cam a10 ? , ~1
07, several shift forks 11 whose other ends are respectively engaged with sliding gears in the transmission gear trains 84a to 84n;
0. - 1103, and a fork guide shaft 111 that slidably supports these shift forks. ．． It is equipped with 111□. The change spindle 106, the shift drum 108, and the fork guide shafts 1111 to 1113 are all arranged parallel to the output shaft 82 and 83 of the transmission 81, and both ends are connected to the partition wall plate 87 and the crankcase 4. It is supported on the left side wall. According to such a configuration, before fixing the partition wall plate 87 to the mission case 10,
A change mechanism 104 is provided on the plate 87 together with the transmission 81.
Its assemblability is good because it can be assembled with
Furthermore, it is possible to confirm the operation of the change mechanism 104 before assembling it into the transmission case 10.

The lubrication device will be explained. First, the lubrication system for the crankshaft 16 and the valve train 31 will be explained with reference to FIGS. 1, 3, 6, and 7. It is provided on the partition plate 87. That is, a pump chamber 115 is formed in the bulkhead plate 87 facing the driven gear 97 of the primary reduction gear 95, and an outer rotor 116 and an inner rotor 117 are housed inside the pump chamber 115. A cover plate 118 is attached to the open end of the pump chamber 115 with bolts 119. Fixed. The inner rotor 117 is connected to the driven gear 97 via an Oldham joint 120 passing through the center of the cover plate 118. In this way, the oil pump 114 can be continuously driven via the primary reduction gear 95 while the engine E is operating, so there is no need to provide a dedicated drive gear train between the crankshaft 16 and the oil pump 114. It ends up being Also, the partition plate 87 is connected to the pump chamber 11.
Since it also serves as a pump case that defines the pump case 5, a dedicated pump case is not required, and the structure can be simplified.

The partition plate 87 is also provided with a suction boat 121 and a discharge boat 122 that open into the pump chamber 115 . rising suction pipe 124
is connected, and the discharge bow 4122 is communicated with an oil gear gallery 126 via an oil passage 125. The oil passage 125 is formed in a protrusion 127 formed on the inner wall of the oil pan 12. Further, the oil gear rally 126 is integrally formed with the crank holder 18 along its longitudinal direction, and has an inlet 126 connected to the oil passage 125 in the center thereof.
a, and the passage area gradually increases from the population 126a toward both left and right ends. This oil gear 126
From there, a plurality of oil supply passages 128, 128, .

According to the operation of the oil pump 114, the lubricating oil in the oil pan 12 is sucked up through the strainer 123, and is sent under pressure through the oil passage 125 to the oil gear rally 126, from where it is pumped to the crankshaft 16 and the valve bag W3t. distributed to the lubricated parts of the

When the lubricating oil in the oil pan 12 passes through the oil passage 125, it is filtered by an oil filter 130. The oil filter 130 is attached to the front surface of the oil pan 12, and has a filter chamber inside thereof through which the oil passage 125 passes, and an element 131 is set in the cough chamber.

Therefore, the oil flowing through the oil passage 125 is
After being filtered, the oil is fed to the oil gear gallery 126.

The front surface 12a of the oil pan 12, on which the oil filter 130 is mounted, is set back from the front surface of the crankcase 4, so that the amount of protrusion of the oil filter 130 from the front surface of the engine E can be kept small.

The oil pan 12 is also provided with a relief valve 133 that regulates the upper limit of the discharge pressure of the oil pump 114 as follows. That is, on the bottom wall of the oil pan 12, a pair of inner and outer bosses 13 are arranged coaxially with a predetermined interval 134.
A drain hole 137 is formed in the outer boss 136, and the inner boss 1 is drained using the hole 137.
35, a valve hole 138 communicating with the oil passage 125 is bored. Further, this boss 135 is provided with a horizontal hole 139 that opens the valve hole 138 into the oil pan 12 .

The valve hole 138 accommodates a piston-shaped valve body 140 that opens and closes the horizontal hole 139, and a valve spring 141 that biases it in the valve closing direction with a predetermined set load. The retaining ring 142 that supports the outer end is attached to the boss 135.
A relief valve 133 is configured by being engaged with.

Therefore, the discharge pressure of the oil pump 114 is increased by the valve spring 141.
When the pressure rises above the pressure specified by the cent load of
The valve body 140 retreats in response to the discharge pressure, and the horizontal hole 139
is opened, excess pressure flows from the oil passage 125 to the valve hole 138.
It is discharged into the horizontal hole 139 through the .

A drain bolt 143 for closing the drain hole 137 is screwed onto the outer boss 136 . In this case, the drain bolt 143 also serves as a blind plug that closes the processing opening of the valve hole 138.

By removing this drain bolt 143, the reservoir in the oil pan 12 can be drained through the drain hole 137. At this time, since the space 134 is provided between the bosses 135 and 136 as described above, the oil drain hole 13
7 is not blocked in any way.

Next, the lubrication system of the transmission 81 will be explained with reference to FIG. The partition plate 87 has a bearing housing 145 in which the discharge boat 122 of the pump chamber 115 and the ball bearings 86 and 89 of the input and output shafts 82 and 83 are fitted.
, 146, the first and second orifices 1 communicate with each other.
47,148 are drilled. On the other hand, the input shaft 82 is formed with a hollow part 82a with both ends closed, and an introduction hole 149 that communicates the hollow part 82a with the bearing housing 145, and a transmission gear on the input shaft 82. A large number of oil supply holes 151 communicating with the sliding surface and the rotating surface,
151... are drilled. The output shaft 83 also has a hollow portion 83 with one end open to the bearing housing 146.
a is formed, and this hollow part 83a is connected to the output shaft 83.
A large number of oil supply holes 152, 152, . . . communicating with the upper transmission gear sliding surface and rotating surface are bored.

Therefore, while the oil pump 114 is operating, the discharge port 12
A portion of the oil discharged into the first and second orifices 14
Bearing housing 145 while weighing 7,148
, 146, and are introduced into the hollow parts 82a, 83a of the output shafts 82, 83, respectively, from which they are distributed to the oil supply holes 151, 151; 152, 152, respectively,
Each part of the transmission gear trains 84a to 84n is lubricated.

When the lubrication system of the transmission 81 is configured in this way, the oil pump 114 and the hollow parts 32a and 83 of the output shafts 82 and 83 are
3a is simplified, and the gear shift a81 can be refueled accurately.

The cooling device will be explained. 1, 10 to 12, a pair of upper and lower housing halves 155 are provided on the left side of the cylinder block 3 and cylinder head 6.
a and 155b are each integrally formed, and these two halves are connected to each other by bolts 153 to form a water pump 154.
A pump housing 155 is configured.

The lower housing half 155b is formed with an outflow boat 157 that reaches the water jacket 156 surrounding the cylinders 2.2, and an inflow pipe that opens into the center of the pump housing 155. 15
8 is attached. A water hose 159 connected to an outlet of a radiator (not shown) is connected to this inflow pipe 158.

Although not shown, the outlet of the water jacket 156 communicates with the inlet of the radiator, as is conventional.

An impeller 160 is installed inside the pump housing 155, and a pump shaft 161 that drives the impeller is attached to a pair of upper and lower bearings 162 and 162' in the upper housing half 155a.
Supported through. This pump shaft 161 is arranged so that its upper end protrudes into the valve train chamber 8, and a drive gear 163 fixed to the intake camshaft 32 is attached to the upper end of the pump shaft 161.
A driven gear 164 is formed that meshes with the. In this way, the pump housing 155 of the water pump 154 can be held by holding part of the cylinder block 3 and cylinder head 6.
Therefore, the structure of the water pump 154 can be simplified, and special piping for connecting the pump housing 155 and the water jacket 156 is not required. Moreover, since both housing halves 155a and 155b are joined together at the same time as the cylinder block 3 and cylinder head 6, the number of assembly steps is reduced accordingly. Moreover, since the impeller 160 occupies a position relatively close to the camshaft 32, they can be connected by a relatively short pump shaft 161.

The starting device will be explained.

In FIGS. 1 to 3 and 9, considering the left and right weight balance of the engine E, the starting motor 167 is
It is installed parallel to the crankshaft 16 in the left-right center of the valley 168 between the back surface of the cylinder block 3 and the top surface of the crankcase 4 . The rotor shaft 169 of this starting motor 167
The right end, that is, the end on the side of the timing transmission 50 protrudes, and a pinion gear 170 is formed there.This pinion gear 170 is connected to a ring gear 172 on the right end of the crankshaft 16 via an intermediate gear shaft 177. connected to.

The intermediate gear shaft 171 includes a rotating shaft 173 that is supported by the crankcase 4 via a pair of left and right bearings 174, 175, and a rotating shaft 173 that is fixed to the left end of the rotating shaft 173 and is connected to the pinion gear 1.
70, and a small diameter gear 177 that is fixed to the right end of the gear and meshes with the ring gear 172, and transmits the rotation of the pinion gear 170 to the ring gear 172 at a two-step speed reduction. I can do it.

By employing such an intermediate gear shaft 171, it is possible to reduce the diameter of the ring gear 172, increase the degree of automatic installation of the starting motor 167, and make the engine E more compact.

As clearly shown in FIG. 1, the ring gear 172 is rotatably supported on the crankshaft 16 via a needle bearing 178, and is connected to the overrunning clutch 1.
It is connected to the crankshaft 16 via 79.

The overrunning clutch 179 includes a clutch inner 180 that also serves as a boss of the ring gear 172, and a clutch outer 181 that is connected to the drive gear 53 of the timing transmission 50 by integral molding, fixing, etc., and surrounds the clutch inner 180. , and a clutch roller 182 interposed between the clutch inner 180 and the clutch outer 181.
It is possible to transmit driving force in only one direction to 1. Therefore, when the starting motor 167 is operated to start the engine E, the rotation of the rotor shaft 169 is reduced in two steps by the intermediate gear shaft 171 as described above, and the rotation of the rotor shaft 169 is reduced by two steps to the ring gear 17.
2 and further transmitted to the crankshaft 16 via the overrunning clutch 179 for cranking. Then, the engine E starts and the clutch outer 18 of the overrunning clutch 179
When the rotational speed of the clutch inner 180 becomes higher than that of the clutch inner 180, the clutch 179 becomes disconnected to prevent the starting motor 167 from overrunning.

C1 Effects of the Invention As described above, according to the present invention, the pump housing is constituted by a pair of housing halves that are integrally formed with the cylinder block and the cylinder head that constitute the engine body, respectively, and are joined to each other. The half body can be integrally molded with the cylinder block and cylinder head, reducing the number of parts and simplifying the structure. Moreover, both housing halves can be joined at the same time as the cylinder block and cylinder head. This makes it possible to improve the ease of assembly.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal cross-sectional rear view of a motorcycle engine (cross-sectional view taken along the line II in FIG. 3), and FIG. 1A is the same as that in FIG. An enlarged view of part A, Fig. 2 is a right side view of Fig. 1, Figs. 3 and 4 are cross-sectional views taken along lines mm and IV-IV of Fig. 1, and Fig. 5 is the clutch of Fig. 1. and enlarged views of the surroundings of the transmission, Figures 6, 7, and 8 are shown in Figure 3.
Vl-Vl line, ■-■ line and ■-■ line sectional view of the figure, No. 9
The figure is a cross-sectional view taken along the line IX-IX in Figure 2, Figure 10 is a cross-sectional view taken along the line X-X in Figure 1, Figure 11 is a cross-sectional view taken along the line XI-XI in Figure 10, and Figure 12 is a cross-sectional view taken along the line X-X in Figure 1. FIG. l...Engine body, 3...Cylinder block, 6
... Cylinder head, 154 ... Water pump, 155
...Pump housing, 155a, 155b...Housing half, 156...Water jacket, 157...
・Outflow boat, 158... Inflow pipe, 160... Impeller Patent Applicant: Honda Motor Co., Ltd. Representative Patent Attorney Ken Ochiai Figure 4 Figure 12 Figure 10

Claims (1)

[Claims] In an engine cooling system in which a pump housing for a water pump for supplying cooling water to a water jacket inside the engine body is connected to one side of the engine body, each is formed integrally with the cylinder block and cylinder head that make up the engine body. 1. An engine cooling device characterized in that a pump housing is constituted by a pair of housing halves that are joined together.