JPH0692725B2 - Engine oil pan device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Purpose of the Invention (1) Field of Industrial Application The present invention relates to a releasable oil pan that regulates the upper limit of the discharge pressure of an oil pump that supplies lubricating oil stored in the oil pan to various parts of an engine. The present invention relates to an oil pan device for an engine, which includes a valve and a drain bolt that discharges lubricating oil in the oil pan to the outside.

(2) Conventional Technology In a conventional oil pan device, a relief valve is accommodated in a valve hole formed from the outer surface of the oil pan, and a blind hole is provided at the processing port of the valve hole. Further, the drain bolt is screwed into a drain hole formed in the bottom wall of the oil pan irrespective of the relief valve.

(3) Problems to be Solved by the Invention In the oil pan device described above, the valve hole and the drain hole have to be individually formed in the oil pan.
There is a problem that there are many processing steps.

The present invention has been made in view of the above circumstances, and the valve hole and the drain hole can be formed in the oil pan in a single drilling process, and a dedicated blind plug for the valve hole is omitted. It is an object of the present invention to provide the above-mentioned oil pan device.

B. Configuration of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a bottom wall of an oil pan, an outer end of the oil pan outside, and an inner end of the oil pan inside. An outer boss and an inner boss lined up coaxially with the inner end of the outer boss with a certain distance from each other are formed.
The outer boss is provided with a drain hole that is closed with a drain bolt during normal operation.The drain hole is used to form a valve hole in the inner boss and the valve hole is used to lubricate the oil in the oil pan with various parts of the engine. The relief valve which communicates with the discharge side of the oil pump to be supplied to and which accommodates the upper limit of the discharge pressure of the oil pump is housed in this valve hole.

(2) Action Since the valve hole is formed in the inner boss by utilizing the drain hole of the outer boss, the drain hole and the valve hole can be formed in a single drilling step.

In addition, if the drain bolt is screwed into the drain hole, the processing hole of the valve hole is closed by the drain bolt, and thus a dedicated blind plug as in the prior art becomes unnecessary.

Further, if the drain bolt is pulled out, the lubricating oil in the oil pan can be guided to the drain hole through the space between the inner and outer bosses, and can be discharged outside without being disturbed by the outer boss.

(3) Example Hereinafter, one example of the present invention will be described with reference to the drawings.

First we will explain the overall structure of the engine, and then
The valve operating device, the timing transmission device, the breather device, the clutch, the transmission, the change mechanism, the lubricating device, the cooling device, and the starting device will be sequentially described.

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

The engine body 1 of the engine E includes a cylinder block 3 including four cylinders 2, 2 ... In series in the left-right direction and slightly inclined forward, and a crankcase 4 integrally connected to the lower end of the cylinder block 3. , A cylinder head 6 which is superposed on the upper end surface of the cylinder block 3 and is bonded by a bolt 5, and a cylinder head 6 which is superposed on the upper end surface of the cylinder head 6 and further connected by a bolt 7 to a cam holder 47 described later. Head cover 9 that defines a valve operating chamber 8 between
And a mission case 10 integrally connected to the rear of the crankcase 4 as main elements. The cylinder block 3, the crankcase 4, and the mission case 10 are integrally molded by casting, and the right and left side surfaces of the crankcase 4 and the mission case 10 are opened for die-cutting at that time, and their open ends. The side cover 11 and the oil pan 12 are connected to each other by bolts 13 and 14, respectively.

The ceiling wall of the crankcase 4 is integrally formed with partition walls between the cylinders 2 and 2 and crank journal support walls 15 and 15 which are vertically connected to the outer walls of the cylinders 2 and 2 at both outer positions. The crankshaft 16 housed in the crankcase 4 has the crank journal support walls 15, 15
, And an integral crank holder 18 connected to the lower ends thereof by bolts 17, 17 ,. The crankshaft 16 is connected to the pistons 19, 19 sliding on the cylinders 2, 2 via connecting rods 20, 20.

On the lower surface of the cylinder head 6, combustion chambers 21, 21 ... Respectively connected to the cylinders 2, 2. The ceiling surface of each combustion chamber 21 is formed in a mountain shape having a ridge line parallel to the crankshaft 16, the inner end of the pair of intake ports 22 and 22 on one slope, and the pair of exhaust ports 23 on the other slope. The inner ends of 23 and 23 open side by side along the ridge line, respectively, and the intake port 2
The outer ends of 2, 22 open on the rear surface of the cylinder head 6, and the outer ends of the exhaust ports 23, 23 open on the front surface of the cylinder head 6.

The spark plug 24 of each combustion chamber 21 has the above intake and exhaust ports 22, 22; 2
It is arranged so as to be surrounded by 3, 23 and is screwed to the cylinder head 6.

An intake valve 25 and an exhaust valve 26 that open and close each of the intake port 22 and the exhaust port 23 are slidably slidable by valve guides 27 and 28 fixed to the cylinder head 6, and
The valves 25 and 26 are arranged so that the distance between the valves 25 and 26 increases toward the valve head.

The intake and exhaust valves 25, 26 are equipped with valve springs 29, 30 for biasing them in the valve closing direction.
A valve operating device 31 for opening and closing the exhaust valves 25 and 26 against the force of 30 is provided in the valve operating chamber 8.

The valve operating device 31 includes an intake cam shaft 32 arranged directly above the intake valves 25, 25 ... Arrangement group and an exhaust cam 26, 26 arranged just above it along the arrangement direction. Exhaust camshaft 33
And a swing-type intake cam follower 36 whose base end is pivotally supported by the cylinder head 6 and whose free end is interposed between the intake cam shaft 32 and the head of each intake valve 25, and the base end is the cylinder head. A swing type exhaust cam follower 37 is supported by the shaft 6 and has a free end interposed between the exhaust cam shaft 33 and the head of each exhaust valve 26.

At that time, as shown in FIG. 3, the pivot 34 of the intake cam follower 36 is located between the intake valve 25 and the spark plug 24, and the pivot 35 of the exhaust cam follower 37 is located between the exhaust valve 26 and the exhaust port 23. Will be placed. In this way, the intake cam follower
The intake port 22 can be linearly raised from the combustion chamber 21 without being interfered with by 36, and the intake resistance can be reduced.
Further, a sufficient space for attachment / detachment can be secured above the spark plug 24 without being interfered with by the exhaust cam follower 37.

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 the corresponding intake and exhaust valves 25, 26 are provided.
A protruding shaft 41a protruding from a shim 41 facing the head of the is inserted into the support hole 40 in a freely rotatable manner. Thus, by selecting the thickness of the shim 41, the valve head clearances of the intake and exhaust valves 25, 26 are properly adjusted, and moreover, the lateral displacement of the shim 41 is prevented by fitting the protruding shaft 41a and the support hole 40. It

The intake camshaft 32 includes a plurality of cam journal support walls 42, 42, which are erected on the bottom wall of the valve operating chamber 8, and bolts 43, 43 attached to them.
It is rotatably clamped by the integral cam holder 44 fixed by. Further, the exhaust cam shaft 33 also includes a plurality of cam journal support walls 45, 45, which are erected on the bottom wall of the valve operating chamber 8, and an integral cam holder 47, which is fixed to these with cam bolts 46, 46.
It is rotatably clamped by.

The intake and exhaust cam shafts 32, 33 are connected to the crank shaft 16 via a timing transmission device 50.

As shown in FIGS. 1 and 2, the timing transmission device 50 is housed in a series of timing transmission chambers 51 formed at the right end portions of the cylinder block 3, the cylinder head 6 and the head cover 9, A drive gear 53 fixed to the right end of the crankshaft 16 via a key 52, a first idle gear 54 meshing with the drive gear 53, a second idle gear 55 meshing with the first idle gear 54, An intake driven gear 56 that is substantially fixed to the right end of the intake cam shaft 32 and meshes with the second idle gear 55, and an intake driven gear 56 that is substantially fixed to the right end of the exhaust cam shaft 33 and also meshes with the second idle gear 55. An exhaust driven gear 57 and a support plate 58 that pivotally supports the first and second idle gears 54, 55 are provided to rotate the crankshaft 16 in two directions.
It is adapted to transmit to both camshafts 32, 33 with a speed reduction ratio of one-half.

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

As shown in FIG. 1A, a fixed gap is provided between the support shaft 60 and a shaft hole 65 formed in the support plate 58 to penetrate the support shaft 60.
66 is provided, and in order to suppress the vibration of the support plate 58 due to the gap 66, elastic rings 67, 67 as a pair of left and right elastic members that are in close contact with the inner surface of the shaft hole 65, for example, O-rings are attached to the support shaft 60. To be done.

In the illustrated example, the upper boss 61 and the shaft hole 65 are concentrically arranged in order to make the support plate 58 compact, but this is not always necessary.

The spindle 60 has a threaded portion 60a at the tip screwed into the inner wall of the timing transmission chamber 51, and a circular head 60b is supported on the outer wall of the chamber 51 via an O-ring 68 to support both ends. It is said that

In the above description, the engine body 1 is made of Al alloy, and the support plate 58 and the drive gear 53 or the driven gears 56, 57 are made of iron material. Therefore, the thermal expansion coefficient of the engine body 1 and that of the timing transmission 50 are greatly different. Moreover, during operation of the engine E, the engine body 1 is more strongly affected by heat than the timing transmission device 50. For this reason, even if the engine main body 1 thermally expands more than the timing transmission 50 and the distance between the crankshaft 16 and the support shaft 60 increases, the support shaft 60 is attached to the shaft of the support plate 58 with the increase. Since the elastic rings 67, 67 only move while being compressed and deformed within the gap 66 between the holes 65, the support plate 58 is not affected by the thermal expansion. As a result, the first and second idle gears pivotally supported by the support plate 58
The axial distance between the drive gear 53 on the crankshaft 16 which supports one end of the support plate 58 and the axial distance between the first idle gear 54, as well as the axial distance between 54 and 55, is not affected by the thermal expansion, and these gears 5
The backlash between 3,54,55 can be kept almost constant at all times, and the crankshaft 16 and the camshafts 32,33
The drive torque can be properly and quietly transmitted to the vehicle.

The thermal expansion of the cylinder head 6 is caused by the second idle gear 55.
, And the backlash between the intake and exhaust driven gears 56, 57 and each of them is affected, but the influence is extremely small because the axial distance between them is relatively short. However, in the illustrated example,
In order to avoid that effect, the driven gears 56 and 57 are fixed to the corresponding cam shafts 32 and 33, and the fixed gear 69,
This fixed gear 69 is divided into a movable gear 70 connected via a torsion spring 71, and the torsional force of the torsion spring 71 elastically clamps the teeth of the second idle gear 55 between the teeth of both gears 69, 70. Therefore, I always try to eliminate backlash.

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

The breather device will be described. As shown in FIGS. 1 and 3, on the upper surface of the cam holder 44 on the intake camshaft 32 side,
A surrounding wall 74 that surrounds a part of the surrounding wall is integrally formed, and the head cover 9 is abutted against the upper end of the surrounding wall 74 via a seal member 76 so that the inside of the surrounding wall 74 serves as a breather chamber 75. The breather chamber 75 is communicated with the valve operating chamber 8 through a through hole 77 provided in the cam holder 44, and is also communicated with the intake system of the engine E or the atmosphere through an air guide pipe 78 attached to the head cover 9.

When the breather chamber 75 is defined by utilizing the cam holder 44 and part of the head cover 9 in this way, a dedicated breather chamber body is not required, and the structure of the breather device can be simplified.
Thus, during operation of the engine E, blow-by gas generated in the crankcase 4 passes through the timing transmission chamber 51 and the valve operating chamber 8
Then, after flowing into the breather chamber 75 through the through hole 77 and expanding, the oil is separated by this, and then flows out to the air guide pipe 78. The separated oil drops into the valve operating chamber 8 through the through hole 77.

The clutch and the transmission will be described. 1 and 5
As shown in the figure, the clutch 80 and the transmission 81 are housed in the mission case 10.

The input shaft 82 and the output shaft 83 of the transmission 81 are arranged in parallel with the crankshaft 16, and a multi-stage transmission gear train 84a-
84n is provided.

The left and right ends of the input and output shafts 82 and 83 are needle bearings 85.
Is supported on the left side wall of the mission case 10 via a ball bearing 86 and a ball bearing 86, respectively, and the right end is the mission case.
The intermediate plate 10 is supported on the partition plate 87 via ball bearings 88 and 89, respectively.

The partition plate 87 has a circular shape, and the mission case 10
While being fitted to the annular stepped portion 90 formed on the inner peripheral surface of
Removably fixed to a plurality of bosses 91, 91 formed on the peripheral wall of the case 10 with bolts 92, 92.

The right end portion 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 crankshaft 16 via the primary reduction gear 95. To be done. The primary reduction gear 95 is composed of 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 a spacer cylinder 99 on the input shaft 82.
Is supported via a needle bearing 100. Thus, the clutch outer 94 is connected to the input shaft 82 via the driven gear 97.
It is rotatably supported by. According to such a configuration, since the transmission 81 can be assembled on the partition plate 87 before the partition plate 87 is fixed to the mission case 10, the assembling property is good, and the transmission case 10 can be easily assembled. It is possible to confirm the operation of the transmission 81 before assembling.

Thus, during operation of the engine E, 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 is transmitted to the input shaft 82 via the clutch inner 93 when the clutch 80 is connected. Then, it is further transmitted to the output shaft 83 via one gear train selected from the transmission gear trains 84a to 84n. The output torque of the output shaft 83 is transmitted to the rear wheels of the motorcycle via the secondary reduction gear device 101 to drive it.

A change mechanism for controlling the transmission 81 will be described. 5 and 8, the change mechanism 104
As is well known, a change spindle 106 having a change pedal 105, a shift drum 108 having a plurality of cam grooves 107 _{1 to} 107 ₃ ... A step feed mechanism 109 for giving a predetermined angle to the shift drum 108 by the rotation thereof, one end of which is connected to the cam grooves 107 _{1 to} 1073, and the other end of which is connected to the transmission gear trains 84 a to 8 _3.
There are several shift forks 110 _{1 to} 110 ₃ engaged with the sliding gears in 4n, and fork guide shafts 111 ₁ and 111 ₂ slidably supporting these shift forks.
The change spindle 106, the shift drum 108, and the fork guide shafts 111 _{1 to} 111 ₃ are all input to the transmission 81,
It is arranged parallel to the output shafts 82 and 83, and both ends thereof are supported by the partition plate 87 and the left side wall of the crankcase 4.
According to this structure, the partition plate 87 is attached to the mission case.
Since the change mechanism 104 can be assembled together with the transmission 81 on the plate 87 before it is fixed to the transmission 10, the assembling property is good, and the operation of the change mechanism 104 is confirmed before the transmission mechanism 10 is assembled. Is possible.

The lubrication device will be described. First, referring to FIG. 1, FIG. 3, FIG. 6 and FIG. 7, the lubrication system of the crankshaft 16 and the valve operating device 31 will be described. The trochoid type oil pump 114 serving as an oil supply source is described above. It is provided on the partition plate 87. That is, the partition plate 87 has a driven gear 97 of the primary reduction device 95.
A pump chamber 115 is formed facing to the inside, the outer rotor 116 and the inner rotor 117 are housed inside, and a lid plate 118 is fixed to the open end by a bolt 119. And this lid plate 11
The inner rotor 117 is connected to the driven gear 97 through an Oldham joint 120 penetrating the central portion. With this configuration, the oil pump 114 can be continuously driven through the primary reduction gear device 95 during the operation of the engine E. Therefore, a drive gear train dedicated to the oil pump 114 is not provided between the crankshaft 16 and the oil pump 114. Complete. Further, the partition plate 87 is located in the pump chamber 11
Since it also serves as the pump case that defines 5, the special pump case is not required and the structure can be simplified.

A suction port 121 and a discharge port 122 that open to the pump chamber 115 are formed in the partition plate 87, and the suction port 12
A suction pipe 124 rising from a strainer 123 installed below the oil surface in the oil pan 12 is connected to 1, and a discharge port 122 is connected to an oil gallery 126 via an oil passage 125. The oil passage 125 is formed in a raised portion 127 formed on the inner wall of the oil pan 12. Also oil gallery 126
Is formed integrally with the crank holder 18 along the longitudinal direction thereof, has an inlet 126a connected to the oil passage 126 at the center thereof, and gradually increases the passage area from the inlet 126a toward both left and right ends. It is expanding. This oil gallery 12
A plurality of oil supply passages 128, 128, which reach the bearing surface for the journal of the crankshaft 16, and a single oil supply passage 129 which reach the lubrication portion of the valve operating device 31 are branched from 6.

Thus, according to the operation of the oil pump 114, the oil pan 1
Lubricating oil inside 2 is sucked up through strainer 123,
The oil is fed under pressure to an oil gallery 126 through 125, and then distributed to a predetermined lubrication portion of the crankshaft 16 and the valve gear 31.

The lubricating oil in the oil pan 12 is filtered by the oil filter 130 when passing through the oil passage 125. The oil filter 130 is attached to the front surface of the oil pan 12, and has a filtration chamber through which the oil passage 125 passes, and an element 131 is set in the chamber. Therefore, the oil flowing through the oil passage 125 is filtered by the element 131 and then fed to the oil gallery 126.

Front 1 of the oil pan 12 where the above oil filter 130 is attached
2a is retracted from the front surface of the crankcase 4, and by doing so, the amount of protrusion of the oil filter 130 from the front surface of the engine E can be suppressed to a small amount.

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, a predetermined gap 134 is formed on the bottom wall of the oil pan 12.
And a pair of inner and outer bosses 135 and 136 arranged on the coaxial line are formed, and a drain hole 137 is formed in the outer boss 136, and the hole 137 is used to connect the inner boss 135 with the oil passage 125. A hole 138 is drilled. The boss 135 also has a valve hole 138.
A horizontal hole 139 is opened to open the inside of the oil pan 12. The valve hole 138 accommodates a piston-shaped valve element 140 that opens and closes the lateral hole 139, and a valve spring 141 that urges the valve element 140 in a valve closing direction with a predetermined set load. The retaining ring 142 supporting the outer end is locked to the boss 135 so that the relief valve 13
3 is composed.

When the discharge pressure of the oil pump 114 rises above the pressure specified by the set load of the valve spring 141, the valve body 14
Since 0 retreats in response to the discharge pressure and opens the lateral hole 139, the surplus pressure is discharged from the oil passage 125 to the lateral hole 139 via the valve hole 138.

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

By removing the drain bolt 143, the stored oil in the oil pan 12 can be discharged 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 is not prevented from flowing out to the drain hole 137.

Next, the lubrication system of the transmission 81 will be described with reference to FIG.
The partition plate 87 has a discharge port 122 of the pump chamber 115.
And first and second orifices 147, 148 that communicate with the bearing housings 145, 146 in which the ball bearings 86, 89 of the input and output shafts 82, 83 are fitted. On the other hand, the input shaft 82 is formed with a hollow portion 82a whose both ends are closed, and the hollow portion 82a is formed in the bearing housing 1.
45, and a large number of oil supply holes 151 for communicating the hollow portion 82a with the sliding surface and the rotating surface of the transmission gear on the input shaft 82.
151 ... and are drilled. Further, the output shaft 83 is also formed with a hollow portion 83a whose one end is opened to the bearing housing 146, and a large number of oil supply holes 152, 152 for communicating the hollow portion 83a with the transmission gear sliding surface and the rotating surface on the output shaft 83. Is drilled.

Thus, during operation of the oil pump 114, a part of the oil discharged to the discharge port 122 is sent to the bearing housings 145 and 146 while being metered to the first and second orifices 147 and 148,
Then, they are introduced into the hollow portions 82a, 83a of the input and output shafts 82, 83, respectively, and are distributed to the oil supply holes 151, 151; 152, 152 from there, respectively, to lubricate the respective portions of the transmission gear trains 84a to 84n.

By configuring the lubrication system of the transmission 81 in this way, the oil passage that connects the oil pump 114 and the hollow portions 82a, 83a of the input and output shafts 82, 83 is simplified, and oil is accurately supplied to the transmission 81. be able to.

The cooling device will be described. Figures 1, 10 through 12
In the figure, on the left side of the cylinder block 3 and the cylinder head 6, a pair of upper and lower housing halves 155a and 15 are provided.
5b are integrally formed, and both halves are bolts 153
Are coupled to each other to form a pump housing 155 of the water pump 154.

The lower housing half 155b is formed with an outflow port 157 which reaches the inlet of the water jacket 156 surrounding the cylinders 2, 2, ...
An inflow pipe 158 that opens to the center of the inside is attached. A water hose 159 is connected to the inflow pipe 158 and is connected to an outlet of a radiator (not shown). Further, the outlet of the water jacket 156 is communicated with the inlet of the radiator, which is not shown and is conventional.

An impeller 160 is mounted in the pump housing 155, and a pump shaft 161 for driving the impeller 160 is an upper housing half 155a.
Is supported by a pair of upper and lower bearings 162, 162 '. The pump shaft 161 is arranged so that the upper end thereof projects into the valve operating chamber 8, and the intake cam shaft 32 is provided at the upper end thereof.
Driven gear 1 that meshes with drive gear 163 fixed to
64 is formed. With this configuration, the pump housing 155 of the water pump 154 can be formed by the cylinder block 3 and a part of the cylinder head 6, so that the structure of the water pump 154 can be simplified and the pump housing 155 and the water jacket can be formed. No special piping is needed to connect the 156. Further, since the impeller 160 occupies a position relatively close to the cam shaft 32, they can be connected by a relatively short pump shaft 161.

The starting device will be described.

In FIGS. 1 to 3 and 9, in consideration of the left and right weight balance of the engine E, the starting motor 167 has a left and right center of a valley 168 between the rear surface of the cylinder block 3 and the upper surface of the crankcase 4. Installed parallel to the crankshaft 16. A rotor shaft 169 of the starting motor 167 has a right end portion, that is, an end portion on the timing transmission device 50 side protruding, and a pinion gear 170 is formed there, and the pinion gear 170 has a crankshaft via an intermediate gear shaft 177. It is connected to a ring gear 172 on the right end of 16.

The intermediate gear shaft 171 includes a rotary shaft 173 supported by the crankcase 4 via a pair of left and right bearings 174, 175, a large diameter gear 176 fixed to the left end portion thereof and meshing with the pinion gear 170, and a right end portion thereof. And a small diameter gear 177 fixed to the ring gear 172 and meshing with the ring gear 172. The rotation of the pinion gear 170 can be transmitted to the ring gear 172 by decelerating in two stages.

According to the adoption of the intermediate gear shaft 171, the ring gear 1
72 smaller diameter, automatic degree of installation of starter motor 167 expanded,
As a result, the engine E can be made 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 crankshaft 16 via an overrunning clutch 179.

The overrunning clutch 179 has a ring gear 172.
The clutch inner 180 also serving as the boss and the clutch outer 181 surrounding the clutch inner 180 by being integrally formed with the drive gear 53 of the timing transmission device 50 by integrally molding, fixing or the like.
And a clutch roller 182 interposed between the clutch inner 180 and the outer 181.
Drive force can be transmitted from the clutch outer 181 to the clutch outer 181 only in one direction. Therefore, when the starting motor 167 is operated to start the engine E, the rotation of the rotor shaft 169 is
As described above, the intermediate gear shaft 171 reduces the speed by two stages, transmits the reduced gear to the ring gear 172, and further transmits it to the crankshaft 16 via the overrunning clutch 179 to crank the crankshaft 16. Then, the engine E starts and the clutch outer 1 of the overrunning clutch 179 is
When the rotation speed of 81 becomes higher than that of the clutch inner 180, the clutch 179 is disengaged to prevent the overrun of the starting motor 167.

C. Effects of the Invention As described above, according to the present invention, the bottom wall of the oil pan, the outer end facing the outside, and the inner end facing the inside of the oil pan, respectively, and a constant from the inner end of the outer boss. And an inner boss that is aligned with the coaxial line at a certain interval, and a drain hole that is closed by a drain bolt during normal operation is formed in the outer boss, and a valve hole is formed in the inner boss by using this drain hole. Since this valve hole is installed, it communicates with the discharge side of the oil pump that supplies the lubricating oil in the oil pan to each part of the engine, and the relief valve that controls the upper limit of the discharge pressure of the oil pump is housed in this valve hole. Drain holes and valve holes can be drilled in a single drilling process, and a dedicated blind plug for the valve hole processing port is not required, thus reducing the processing man-hours and the number of parts, and greatly contributing to cost reduction. can do.

[Brief description of drawings]

The drawings show an embodiment of the present invention. Fig. 1 is a longitudinal rear view of a motorcycle engine (a sectional view taken along the line I-I of Fig. 3), and Fig. 1A is an enlarged view of an IA portion of Fig. 1. 2 is a right side view of FIG. 1, and FIGS. 3 and 4 are lines III-III of FIG.
IV-IV sectional view, FIG. 5 is an enlarged view around the clutch and the transmission of FIG. 1, FIG. 6, FIG. 7 and FIG. 8 are of FIG.
VI-VI line, VII-VII line and VIII-VIII line sectional view, FIG. 9 is a IX-IX line sectional view of FIG. 2, FIG. 10 is a XX line sectional view of FIG. 1, and FIG. Is a cross-sectional view taken along the line XI-XI in FIG. 10, and FIG.
FIG. 11 is a sectional view taken along line XII-XII in FIG. 11. 12 …… Oil pan, 114 …… Oil pump, 133 …… Relief valve, 134 …… Spacing, 135 …… Inner boss, 136 …… Outer boss, 137 …… Drain hole, 138 …… Valve hole, 139 …… Side hole, 140 ... Valve element, 141 ... Valve spring, 142 ... Stop ring, 143 ...
... Drain bolt

Claims (1)

[Claims] 1. An outer boss on the bottom wall of the oil pan, the outer end of which faces the outside and the inner end of which faces the inside of the oil pan, and the outer boss and the inner end of the outer boss are aligned on a coaxial line with a certain distance. An inner boss is formed, and a drain hole that is closed by a drain bolt at normal time is formed in the outer boss.The drain hole is used to form a valve hole in the inner boss and the valve hole in the oil pan. An oil pan device for an engine, which communicates with the discharge side of an oil pump that supplies the internal lubricating oil to each part of the engine, and accommodates a relief valve that regulates the upper limit of the discharge pressure of the oil pump in this valve hole.