JP2904221B2 - Engine oil pan gasket - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil pan gasket interposed between joint surfaces of a crankcase and an oil pan of an engine to seal the joint surfaces. It is.

[Prior art] This type of oil pan gasket is disclosed in
As shown in Japanese Patent No. 8214, the upper part of the lubricating oil stored in the oil pan is depressed to have a shape close to the oil surface, and a large number of minute through holes formed in the depressed part pass through the inside of the oil pan. By returning the lubricating oil to the
There is a configuration in which stable lubricating oil is supplied to an engine or the like.

[Problems to be Solved by the Invention] According to such an oil pan gasket, since the recessed portion also serves as a so-called oil filter, when the engine is operated at a medium / high rotation speed, the oil pan gasket is moved from the recessed portion to the inside of the oil pan. It is assumed that the lubricating oil does not return quickly and the amount of lubricating oil in the oil pan gradually decreases. And
A phenomenon in which the lubricating oil rises along the inner wall of the oil pan as the internal pressure in the crankcase increases (so-called oil rise)
Occurs.

The present invention has been made in view of the above circumstances, and ensures a stable lubricating oil in which the amount of lubricating oil returned to the oil pan is ensured even during operation at medium and high speeds, and oil rise is effectively suppressed. It is an object of the present invention to provide an oil pan gasket for an engine in which stable supply of the oil pan is achieved.

Means for Solving the Problems In order to achieve the above object, the present invention provides an oil pan gasket interposed between the joining surfaces of a crankcase and an oil pan constituting an engine to seal the joining surfaces. The oil pan gasket is provided with a protruding portion protruding an appropriate length into the oil pan along the joint surface over the entire circumference of the oil pan, and a lubricating oil is returned to a central portion inside the protruding portion. An opening is also formed that also serves as an oil relief valve and an oil relief valve that allows the lubricating oil supply system to release lubricating oil from the lubricating oil supply system when the pressure of the lubricating oil supply system is about to exceed a predetermined value. A through hole to be penetrated is formed separately from the opening.

Further, it is preferable that the relief valve penetrating through the through hole is inserted and attached to the crankcase from below.

Preferably, the relief valve is disposed at a front end of the oil pan.

Further, it is preferable that the opening is formed by a plurality of lubricating oil passage holes.

[Operation] According to the oil pan gasket of the engine of the present invention,
Even when the engine is operated at medium and high speeds, the lubricating oil that has been lubricated returns to the oil pan surely and quickly through the opening. Further, even if the lubricating oil in the oil pan rises along the wall surface of the oil pan due to an increase in the internal pressure of the crankcase, the lubricating oil hits the projecting portion and is prevented from further rising.
Further, the bubbles contained in the lubricating oil returning to the inside of the oil pan hit the protruding portion, so that the bubbles are reduced or collapsed.

Also, when the engine is operated at a medium / high speed and the pressure of the lubricating oil supply system is about to reach a certain value or more, the oil relief valve opens to allow the lubricating oil to escape to the oil pan side. At this time, since the through-hole for penetrating the oil relief valve is formed in the projecting portion separately from the opening, the lubricating oil returning from the oil relief valve and the lubricating oil returning through the normal lubricating oil supply system And does not interfere. further,
Since the lubricating oil returned from the oil relief valve is directly returned to the oil pan, the returned lubricating oil is immediately supplied from the oil strainer for lubricating oil supply.

As described above, a constant amount of the lubricating oil stored in the oil pan is always maintained, and as a result, a stable supply of the lubricating oil to the engine, the transmission, and the like is achieved.

Hereinafter, an embodiment in which the present invention is applied to a motorcycle engine will be described with reference to the drawings. In the description, directions such as front and rear and left and right are directions with respect to the vehicle body.

1 and 2 show a front view and a side view of the motorcycle 1, respectively.

The motorcycle 1 includes a body frame 2, a pair of left and right front forks 3 rotatably supported at the front end of the body frame 2, and a steering handle 4 attached to the upper end of the front fork 3. A front wheel 5 rotatably supported by a front fork 3 and a body frame 2
A fork 6 swingably supported on the rear fork 6, a rear wheel 7 rotatably supported on the rear end of the rear fork 6, and a water-cooled engine 8 according to the present embodiment supported on the body frame 2 And a radiator 9 also supported by the body frame 2, and a fuel tank disposed above the body frame 2
10 and a driver's seat 11 and a passenger's seat 12 disposed behind the fuel tank 10.A front cowl 13 and an under cowl 14 at the front of the vehicle body, and a rear cowl 15 at the rear of the vehicle body. Covered by

The body frame 2 starts from the head pipe 16 at the front end.
A pair of left and right main frames 19 having a hollow angular cross-section, which are integrally provided with a front engine hanger 17 and a rear engine hanger 18 which extend rearward and diagonally downward, and also extend rearward and diagonally downward at the bottom. Arm 20
a, 20b and a pair of left and right hollow sub-frames 20 formed with a bracket portion 20c extending downward and a front arm portion 20a connected to the rear end of each main frame 19, and each bracket portion 20c of these sub-frames 20 An upper cross member 21 and a lower cross member 22 which extend laterally between the upper part and the lower part and are provided integrally with the sub-frame 20,
Arm 20b on the rear side of each subframe 20 and subframe 2
The seat rail 23 is formed by a pair of right and left upper rails 23a and lower rails 23b, each of which is bolted to the 0 bracket portion 20c and extends rearward and obliquely upward, and rear ends of which are welded to each other. The mainframe 19
The arm 20a on the front side of the sub-frame 20 is connected to the arm 20a via a joint member 24 inserted and welded inside the two.

The head pipe 16 constituting the body frame 2 includes:
A steering stem 26 integrally provided with a lower bridge 25 at a lower end is rotatably inserted around an axis, and a top bridge 27 is fixed to an upper end protruding from the head pipe 16 of the steering stem 26. Have been.

The front fork 3 includes a bottom case 28, and an inner tube 29 slidably inserted into the bottom case 28 via a cushion (not shown). The inner tube 29 includes a top bridge 27 and a lower bridge. It is inserted and fixed at both ends of 26. As a result, the front fork 3 is integrated with the steering stem 26 via the top bridge 27 and the lower bridge 25 and is rotatable.

The handle 4 includes a pair of left and right handles 30.
And a grip 31 attached to the handlebar 30. The end of the handlebar 30 is fitted and fixed to the upper end of each front fork 3 projecting from the top bridge 27.

The front wheel 5 includes a wheel 33 having an axle 32 provided at an axis.
A tire 34 is mounted on the outer periphery of the front fork 3. Both ends of the axle 32 are supported by the lower end of the bottom case 28 of each front fork 3. The left and right bottom cases 28 include
A front fender 35 that covers above the front wheel 5 is supported.

On both left and right sides of the wheel 33 of the front wheel 5, rotors 37 constituting a front disc brake device 36 are fixed coaxially and integrally with the wheel 33, respectively. The front disc brake device 36 is provided with a brake caliper 39 fixed to the rear of the bottom case 28 of each front fork 3 via a stay 38 and holding the rotor 37 in operation to brake the rotation thereof by frictional force. And a brake lever 41 attached to the handle bar 30 of the right handle 4 to operate the brake caliper 39 via the cable 40
It is composed of

The rear fork 6 has a pair of left and right forks 43 extending rearward from a base 42 at the front end thereof. The base 42 is pivotally supported by a pivot 44 provided on the bracket 20c of the sub-frame 20. Thereby, the fork portion 43 can swing up and down.

The rear wheel 7 has a slightly larger diameter than the front wheel 5 and, similarly to the front wheel 5, a tire 47 is mounted on an outer periphery of a wheel 46 provided with an axle 45 at an axial center. By being supported by the rear end of the fork 43 of the rear fork 6, the rear fork 6 swings integrally with the rear fork 6.

The swing that the rear wheel 7 receives from the road surface is buffered by the rear cushion unit 48. The rear cushion unit 48 includes a cushion body 52 having a damper 49, a spring 50, and the like, the upper end of which is pin-connected to the upper cross member 21 via a stay 51;
A connecting rod 53 having one end connected to the pin 22 and a connecting rod 53 having a triangular shape, and each apex being fixed to the other end of the connecting rod 53 and a lower portion of the fork portion 43 of the rear fork 6 near the center of the front. , And a cushion arm 55 pin-connected to the lower end of the cushion body.

The rear wheel 7 is also provided with a rear disc brake device 56 similar to the front disc brake device 36 of the front wheel 5.

The rear disc brake device 56 is coaxially and integrally fixed to the right side of the wheel 46 with the wheel 46,
The rotor 57 is fixed below the right fork portion 43 of the rear fork 6 via a stay 58 in an operating state.
A brake caliper 59 for braking the rotation of the sub-frame 20 by frictional force, and a bracket 20 on the right side of the sub-frame 20.
and a brake pedal (not shown) for operating the brake caliper 59, which is attached to the c. A torque rod 60 extends between the front end of the brake caliper 59 and the lower part of the pivot 44 in the bracket 20c on the right side of the sub-frame 20. In addition, the rear fork 6 is integrally provided with a rear guard 61 that rises from the center in the left-right direction of the base portion 42 while gently curving rearward and obliquely upward to cover the upper front side of the rear wheel 7.

A chain sprocket 62 is fixed to the left side of the wheel 46 of the rear wheel 5 coaxially with the wheel 46.
63 are wound. Further, a fork portion 43 on the left side of the rear fork 6 has a chain cover for covering an upper rear portion of the drive chain 63 and an upper portion of the chain sprocket 62.
64 has been fixed.

The engine 8 includes a cylinder block 68 including a cylinder block body 65, a cylinder head 66, and a cylinder head cover 67, and a crankcase 69 connected to the cylinder block 68. Is a parallel four-cylinder four-cycle engine in which four cylinders 70 are arranged in parallel. And
In the engine 8, the cylinder block 68 is tilted slightly forward, and the cylinder block 68 is connected to the front engine hanger 17 and the rear engine hanger 17 of the main frame 19.
18 and both sides of the rear part of the crankcase 69 are bolted to the bracket 20c of the sub-frame 20, respectively, so that the sub-frame 20 is supported by the vehicle body frame 2.

A carburetor 71 that supplies an air-fuel mixture into the cylinder block 68 by the suction action of the engine 8 is connected to a rear portion of the cylinder block 68 of the engine 8.

Also, at the front of the cylinder block 68, each cylinder 70
Exhaust pipes 72 are connected to each of the four exhaust pipes.
72 (referred to as a first exhaust pipe 72a, a second exhaust pipe 72b, a third exhaust pipe 72c, and a fourth exhaust pipe 72d from the left side of the vehicle body) extend downward from a connection end to the cylinder block 68 and are aligned below the engine 8. Bends and further bends the crankcase 69
Extends rearward along the lower surface of the crankcase 69, and is integrated into one collecting pipe 73 at the lower rear side of the crankcase 69. The collecting pipe 73 has its tip disposed on the right side of the rear wheel 7 while rising diagonally to the right and rearward.
A cylindrical silencer 74 that extends diagonally upward so as to be in line with the rear end portion is mounted.

As shown in FIG. 2, the exhaust pipes 72a to 72d are disposed at a position slightly to the left of the center line of the vehicle body below the engine 8 and are in contact with the right side of the first exhaust pipe 72a. A second exhaust pipe 72b is disposed in contact with these lower sides, and a third exhaust pipe 72b is in contact with the second exhaust pipe 72b and the fourth exhaust pipe 72d.
c are arranged, and the cross section is grouped in a parallelogram shape which is inclined to the left (the right in FIG. 2) as a whole.

 The engine 8 will be described later in detail.

The radiator 9 is a horizontally long rectangular cross-flow type in which a cooling water inflow-side tank 76 is connected to the right side of the core 75 and an outflow-side tank 77 is connected to the left side. And is supported by the main frame 19 and the front engine hanger 17.

The fuel tank 10 is disposed above the main frames 19 and between the sub-frames 20 and is fixed to the frames 19, 20. A recess 10a is formed in the lower surface on the front side of the fuel tank 10, and an air cleaner 78 is housed in the recess 10a. An air suction pipe 79 bent downward is connected to a front portion of the air cleaner 78, and a suction port 71a of the carburetor 71 is inserted into a rear portion thereof.

The front cowl 13 is formed in a streamline shape from the front to the rear of the head pipe 16 and
And the radiator 9 and both sides of the cylinder block 68 of the engine 8, and the handle 4
A notch 13a is provided to avoid interference with the vehicle body, and a notch 13b substantially U-shaped when viewed from the front is provided at the upper end of the front portion. A transparent screen 80 that extends while curving upward to cover the front fork 3 is provided integrally.

The front cowl 13 has a front end portion supported by a cowl stay 81 fixed to the head pipe 16 and extending forward, and a lower portion of the rear portion of the screen 80 is connected to the main frame.
The main frame 19 is fixed to the main frame 19 of the vehicle body frame 2 by bolts and the like.

An air inlet 83 is formed in the front cowl 13 at a position in front of both corners above the radiator 9. In the center of the front end, two rectangular headlight mounting ports 84 are formed side by side, and these headlight mounting ports 84 have rectangular headlights fixed to the front end of the cowl stay 81. There are 85 each. Also, at the upper center of the cowl stay 81,
A meter unit 86 to which a speedometer, an engine tachometer, and the like are attached is fixed. Directional indicators 87 are attached to the front cowl 13 on both sides of the front and below the air inlet 83.

The under cowl 14 has a substantially U-shaped cross section and continuously extends from the lower end of the front cowl 13 to the crankcase of the engine 8.
Covers both sides of 69 and exhaust pipe 72 and has front cowl
13 is fixed by bolts or the like.

The rear cowl 15 is formed so as to cover the side and the upper side of the seat rail 23 composed of two upper rails 23a and two lower rails 23b on the left and right sides, and a rearwardly protruding bulging portion 15a is integrally formed. And are attached to the rails 23a and 23b by fitting means such as hooks.

The fuel tank 10 and the bulging portion in the rear cowl 15
The recess 88 formed by the rear cowl 15a is a seating position for the driver of the motorcycle 1.
The driver seat 11 is provided on the upper surface, and the bulging portion 15
The occupant seat 12 is provided on the upper surface of a.
A battery 89 is provided below the rear cowl 15 where the driver's seat 11 is provided.A tail lamp 90 also serving as a stop light is attached to the rear end of the rear cowl 15, and a rear light is provided therebelow. A rear fender 91 extending diagonally downward is provided. Further, on both sides of an upper portion of the rear fender 91, a direction indicator 92 is provided.
Is attached.

Next, the engine 8 will be described in detail with reference to FIGS.

The engine 8 has a cylinder block body as described above.
65, a cylinder block 68 composed of a cylinder head 66 and a cylinder head cover 67, and a crankcase 69.The crankcase 69 includes an upper case 69a and a lower case 6.
The upper case 69a and the cylinder block body 65 are integrally formed by casting. Further, an oil pan 93 is joined below the lower case 69b.

FIGS. 3 and 4 show a boss 94 provided at the rear of the cylinder block body 65 for fixing the main frame 19 to the rear engine hanger 18 and the sub-boss provided at the rear of the upper case 69a and the lower case 69b. Frame 20
The fixing boss 95 for the bracket portion 20c is shown.

Four cylinders 70 are arranged in parallel in the cylinder block 68, and a piston 97 is slidably fitted in these cylinders 70 via a casting sleeve 96. These pistons 97 are connected to the crankcase 69 via connecting rods 98.
A crank sprocket 99 is connected at one end (in this case, at the right end) to a crankshaft 101 having a lubricating oil supply oil hole 100a formed at the journal portion 100. It reciprocates up and down in the cylinder 70.

As shown in FIG. 3, the cylinder head 66 is provided with combustion chambers 102 each formed by the cylinder head 66 and each piston 97 reaching the top dead center. As a result, an ignition plug 103 is screwed in, and further, an intake passage 104 and an exhaust passage 105 that communicate each combustion chamber 102 with the outside are formed. These passages 104, 10
The intake port 106 and the exhaust port 107, which are the openings of the respective combustion chambers 102, are formed two by two. Above the cylinder block body 65, an intake valve 108 and an exhaust valve for opening and closing the ports 106, 107 are provided. 109 are provided respectively.

The intake valve 108 and the exhaust valve 109 have a valve stem 110 having an umbrella-shaped valve body 110a that actually opens and closes the ports 106 and 107, and biases the valve stem 110 upward so that the valve body 110a The valve stem 111 includes a valve spring 111 for closing the ports 106 and 107 and a cylindrical valve lifter 112 mounted on the upper end of the valve stem 110. The valve stem 110 slides on a valve guide 113 fitted on the cylinder head 66. It is movably inserted.

On the cylinder head 66, an intake camshaft 114 and an exhaust camshaft 115 for operating each intake valve 108 and each exhaust valve 109 are provided on the crankshaft 101.
And are arranged in parallel.

The camshafts 114 and 115 are supported by a bearing cap 117 fixed to the cylinder head 66 by fastening bolts 116 so as to be rotatable around the axis. On the peripheral surface, the intake valve 108 and the exhaust valve 109 are provided. The intake side cam 118 and the exhaust side cam 119 are integrally formed correspondingly, and further, on the right end, a ridge 120 that engages with the bearing cap 117 and regulates axial movement is integrally formed. I have.

Further, cam sprockets 121 and 122 are integrally provided at the right ends of the camshafts 114 and 115, respectively.A cam chain 123 is wound around the cam sprockets 121 and 122 and the crank sprocket 99 of the crankshaft 101. The camshafts 114 and 115 rotate with the rotation of the crankshaft 101.

As the camshafts 114 and 115 rotate, the peripheral surfaces of the cams 118 and 119 slide in contact with the valve lifters 112 of the respective intake valves 108 and the respective exhaust valves 109 to reciprocate the valve stem 110 up and down. Thereby, the intake port 106 and the exhaust port 107 open and close.

As shown in FIG. 4, a cam chain guide 124 is provided on the outer peripheral side of the cam chain 123 between the cam sprocket 122 of the exhaust side cam shaft and the crank sprocket 99.
The cam sprocket 1 of the intake side camshaft 114
Cam chain 123 between 21 and crank sprocket 99
A cam chain tensioner 125 for suppressing the flapping of the cam chain 123 is arranged on the outer peripheral side of the cam chain.

One end of the cam chain tensioner 125 is pin-coupled to the cylinder head 66 so that the cam chain tensioner 125 can swing.
And a piston 128 fitted in a piston holder 127 disposed in the cylinder block main body 65 and constantly pressing the swinging end of the tension slipper 126 against the cam chain 123 by hydraulic pressure. ing.

An exhaust port 71b of the carburetor 71 having a piston valve 129 is connected to an external opening of the intake passage 104 by a cab insulator 130. Tube 72 (72a-72
The connection ends of d) are connected by stud bolts 131, respectively.

The cylinder head cover 67 joined on the cylinder head 66 communicates with the cylinder head cover 67 and the crankcase 69 via a cam chain chamber 123a in which the cam chain 123 is disposed, and is generated in the crankcase 69. A breather chamber 132 for separating oil contained in blow-by gas to be blown out is provided. The breather room 132
The blow-by gas from which oil has been separated at
It is discharged to the atmosphere from an air guide tube (not shown) connected to 2.

Also, as shown in FIG.
At the right end of 1 is provided a pulser rotor 133 that rotates integrally with the crankshaft 101, and an ignition timing detection mechanism 136 composed of a pulse generator 135 supported by a generator cover 134 fixed to cover the crankcase 69.

At the left end of the crankshaft 101, a rotor 137 that rotates integrally with the crankshaft 101, and a crankcase
An AC generator 140 including an AC generator cover 138 fixed to 101 and a stator 139 supported is provided.

Further, a starter motor driven sprocket 141 is mounted on the crankshaft 101 inside the AC generator 140 via a needle bearing. The start motor driven sprocket 141 is connected to the rotor 137 via a one-way clutch 142 and has a starter motor drive sprocket 144 of a starter motor 143 disposed on the left side in the upper case 69a.
And a chain 145.

Here, a cooling system of the engine 8 by the radiator 9 will be briefly described with reference to FIG. 1 to FIG.

A water pump 147 in which an impeller 146 rotates in accordance with the rotation of the crankshaft 101 is disposed substantially at the center left side in the front-rear direction in the lower case 69b of the crankcase 69. The connection pipes 148, 149, and 150 are branched and connected. A connecting pipe 151 is integrally provided on the front left side of the cylinder block main body.
2, 153 are connected. Further, a connection pipe 154 facing upward is provided on the rear right side of the cylinder head 66.

The connecting pipe 148 is connected to the outlet 77a of the outlet tank 77 of the radiator 9 via an inlet radiator hose 155, and the connecting pipe 149 is connected to the one branch pipe 152 via a water pipe 156. Tube 150 is water pipe 15
7 is connected to the other branch pipe 153. The water pipe 157 passes through a case 159a of an oil filter 159 in a lubricating oil supply device 158 described later. The connection pipe 154 is connected to an inflow port 76a of the inflow tank 76 of the radiator 9 via an outflow radiator hose 160.

Then, by the operation of the water pump 147, the cooling water is formed in the cylinder head 66 from the water jacket 65a formed in the cylinder block body 65 via the radiator 9 → the inflow-side radiator hose 155 → the respective water pipes 156 and 157. The cooling water flows through the water jacket 66a and flows back from the outlet radiator hose 160 to the radiator 9, thereby cooling the engine 8.

Next, a transmission 161 connected to the engine 8 and a change mechanism 162 for switching and controlling the transmission 161 will be described.

The transmission 161 is, as shown in FIG.
9, a transmission case 163 integrated with the lower case 69b, and each needle bearing 1 parallel to the crankshaft 101.
The hollow main shaft 168 and the counter shaft 169 (both are spline shafts) rotatably disposed via the ball bearings 64, 165 and the respective ball bearings 166, 167, and are provided on these two shafts 168, 169, respectively, and mesh with each other. Transmission gear groups 170a to 170f and 171a to 171f, a primary driven gear 173 provided at the right end of the main shaft 168 and meshing with the primary drive gear 172 of the crankshaft 101, and a clutch mechanism also provided at the right end of the main shaft 168 174, and an operating rod 175 that is inserted into the main shaft 168 so as to be movable in the axial direction and connects and disconnects the clutch mechanism 174.

The space between the main shaft 168 and the operating rod 175, and the inside of the counter shaft 169 are lubricating oil supply passages 176 and 177, respectively. And oil holes 178 and 179 for supplying lubricating oil to the transmission gear groups 170a to 170f and 171a to 171b, and the clutch mechanism 174, respectively.

According to the transmission 161, the power of the engine 8, that is, the rotation of the crankshaft 101 is transmitted to the main shaft via the primary driven gear 173 and the clutch mechanism 174.
168, and subsequently, the transmission gear groups 170a to 170f, 171
The transmission is transmitted to the countershaft 3 through the meshing of a to 171f, and further transmitted from the driven sprocket 180 fixed to the left end of the countershaft 169 to the rear wheel 7 via the drive chain 63.

The primary driven gear 173 includes a main gear 173.
a and a sub gear 173b, and these gears 173a, 173b
Although it is relatively rotatable, its rotation is regulated by the damper spring 181 and the primary drive gear 1
The structure is such that backlash in engagement with the gear 72 is suppressed, and is mounted on the main shaft 168 via a sleeve 182 and a needle bearing 183 so as to be relatively rotatable. An oil pump drive sprocket 184 that rotates integrally with the primary driven gear 6 is fitted to the sleeve 182. The oil pump drive sprocket 184 is connected to an oil pump 186 described later by a chain 185.

Next, the clutch mechanism 174 will be described. As shown in FIG. 5, the clutch mechanism 174 includes a clutch outer 187 riveted to the primary driven gear 173, and a clutch outer 187 housed in the clutch outer 187. The clutch center 188 which rotates integrally with the shaft 168, the clutch outer 187 side and the clutch center 18
The friction plates 187a ..., 188a ... on the eight side, and both these friction plates 187a
, 188a... Are pressed against each other.

The clutch pressure plate 189 is provided to be rotatable around the axis of the main shaft 2 via a ball bearing 191 with respect to an end piece 190 supporting one end of the operation rod 175, and a clutch spring
The friction plates 187a ..., 188a ... are pressed against each other by pressing to the left by the clutch mechanism 174.
Is connected. Then, when the operating rod 175 moves rightward, the clutch pressure plate 189 moves integrally in the same direction, and at this time, the clutch mechanism 174 is disconnected.

The axial movement of the operating rod 175 is performed by a clutch release 193 provided on the left side of the crankcase 69. The clutch release 193 is provided with a release shaft 194 that engages with the end of the operating rod 175 and the rack and pinion.
And a release lever 195 fixed to the upper end of the release shaft 194, a return spring 196, and the like. The release lever 195 is operated by a clutch lever 197 mounted on the handle lever 30 of the left handle 4. A wire (not shown) is connected.

When the clutch wire is operated (pulled) by the clutch lever 197, the release shaft 194 is rotated through the release lever 195, and at the same time, the operation rod 175 moves rightward, and the clutch mechanism 174 Will be in a disconnected state.

The change mechanism 162 for switching control of the transmission 161 will be described. As shown in FIG. 6, the change mechanism 162 includes a change spindle 198 rotatably supported by a transmission case 163, and several A shift drum 199 having a cam groove 199a formed therein and rotatably supported by a transmission case 163 via a ball bearing 200;
The shift pin 201a is arranged at one end of the shift drum 199 and integrally rotates with the shift drum 199.
The shift drum center 201 on which the shift drum 201b is formed, the shift plate 202 in which the engaging portion 202a fixed to the right end of the change spindle 198 and provided at the tip engages with the shift pin 201a of the shift drum center 201, and the transmission case 163 A stopper plate 203, which is fixed and its tip engages with the engaging recess 201b of the shift drum center 201 to regulate the rotation angle of the shift drum 199, and the outer periphery of the shift fork shaft 204 supported by the transmission case 163 Is mounted slidably in the axial direction of the shift fork shaft 204,
One end is in the cam groove 199a of the shift drum 199, and the other end is each gear 17 of the main shaft 186 and the counter shaft 169.
0a to 170f and a plurality (three in this case) of shift forks 205 that are appropriately engaged with 171a to 171f.

The change spindle 198, the shift drum 199, and the shift fork shaft 204 are arranged in parallel with the main shaft 168 and the counter shaft 169 of the transmission 161 respectively.

Then, when the change spindle 198 is rotated by a predetermined angle by a change pedal (not shown) which is spline-fitted to an end of the change spindle 198 protruding from the transmission case 163, this rotation is performed via the shift plate 202 and the shift drum center 201. As the shift fork 205 is appropriately slid by the rotation of the shift drum 199, the transmission gears 170a to 170f
The meshing between the transmission gears 171a to 171f and the transmission gears 171a to 171f can be changed as appropriate.

Note that the transmission case 163 has the clutch mechanism 174 and the driven sprocket 1 at the end of the counter shaft 169.
A clutch cover 206 and a driven sprocket cover 207 that cover 80 are respectively fixed.

By the way, the engine 8 and the transmission 161 having the above configuration are
The lubricating oil supply device 158 provided below the engine 8
Thereby, each sliding portion is lubricated.

As shown in FIG. 4, the lubricating oil supply device 158 is integrally fixed to a lower portion of the lower case 69b of the crankcase 69, and stores the lubricating oil L therein.
93 and an oil strainer 208 immersed in the lubricating oil L
And the oil pump 186 mounted in the crankcase 69 and connected to the oil strainer 208 via a pipe 209.
The oil filter 1 fixed to the front of the crankcase 69 and connected to an oil pump 186 via an oil passage 210
59 and an oil reel valve 211 provided in the middle of the oil passage 210 and immersed in the lubricating oil L.

The oil pump 186 is connected to the main shaft 1 as described above.
Chain 1 to 68 oil pump drive sprocket 184
The lubricating oil L is sucked from an oil strainer 208 and sent from a pipe 209 to an oil filter 159 via an oil passage 210, and then transmitted from an oil passage 212 to a transmission 161 (Main shaft 168, counter shaft 169, clutch mechanism 174
) And to the engine 8 (the crankshaft 101, the piston 97, each of the camshafts 114, 115, etc.) through the main gallery 213 branched from the middle of the oil passage 212.

Then, the lubricating oil L that has completed the lubricating operation returns to the oil pan 93 and is stored therein, and is circulated again through the above-described path. A part of the lubricating oil supplied to the engine 8 is
As shown in FIG. 4, the cam chain tensioner 125 is supplied into the piston holder 127 of the cam chain tensioner 125 through the oil passage 214 and constantly presses the piston 128.
It is designed to be used as hydraulic oil.

The lubricating oil is cooled by the cooling water passing through the water pipe 157 when passing through the oil filter 159.

In the circulation of the lubricating oil L, for example, the engine 8
The oil pressure of the lubricating oil L to be pumped increases as the (crankshaft 101) rotates at a high speed and reaches a certain oil pressure, and the oil relief valve 211 operates to release the lubricating oil L passing through the oil passage 210. An appropriate amount is returned into the oil pan 93, and the oil pressure is adjusted so as not to increase any more.

The oil relief valve 211 normally communicates with the oil passage 210 and a discharge port 215a for the lubricating oil L is biased by a spring 216 into a bottomed cylindrical outer cylinder 215 formed in the body of the oil relief valve 211. When the lubricating oil L passing through the oil passage 210 reaches a certain oil pressure as described above, the inner cylinder 217 is moved to the spring 216 by the lubricating oil L. By moving against
The discharge port 215a is opened, and the lubricating oil L is discharged from the discharge port 215a into the oil pan 31.

Now, the joint surface 2 of the oil pan 93 and the lower case 69b
An oil pan gasket 220 according to the present embodiment that seals between the joint surfaces 218 and 219 is interposed between the joints 18 and 219.

The oil pan gasket 220 is formed from a thin metal plate, and is formed wider than the joint surfaces 218 and 219 as shown in FIG. Inside the portion (outside of the two-dot chain line) 220a, the oil pan along each joint surface 218, 219 integrally with this outer peripheral portion.
A protruding portion 220b protruding in an appropriate length toward the inside of 93 is formed, and is wider than each of the joining surfaces 218 and 219. The width of the protruding portion 220b is substantially uniform, and an opening 220c is formed in a central portion on the inside thereof, and lubricating oil returns to the oil pan 93 from the opening 220c.

And this oil pan gasket 220
After fitting to the joining surface 219 of 9b, the joining surface 218 of the oil pan 93
Are fixed together with the oil pan 93 to the lower case 69b by bolts 221 screwed into the lower case 69b, thereby sealing between the joint surfaces 218 and 219 of each other. In addition,
A plurality of through holes 222 for bolts 221 are formed at equal intervals in the outer peripheral portion 220a, and holes 223 for passing the oil relief valve 211 are formed in portions of the protrusion 220b corresponding to the oil relief valve 211. Have been.

According to the oil pan gasket 220, the engine 8
Lubricating oil L that has been lubricated even if
Is reliably and quickly returned to the oil pan 93 through the opening 220c, so that the lubricating oil L always stored in the oil pan 93
Is held in a fixed amount. Further, even if the engine 8 is operated at a medium / high rotation speed and the internal pressure of the crankcase 69 is increased, the lubricating oil stored in the oil pan 93 rises along the inner wall of the oil pan 93, but the lubricating oil L remains in the oil pan. When the gasket 220 hits the protruding portion 220b, the gasket 220 is prevented from further rising, and the oil rising phenomenon does not occur. Further, the bubbles contained in the lubricating oil L returning to the inside of the oil pan 93 hit the protruding portion 220b, so that the size of the air bubbles is reduced or crushed. As a result, stable supply of lubricating oil to the engine 8, the transmission 161 and the like is achieved.

8 and 9 show another embodiment of the present invention.
This oil pan gasket 224 has a large number of round holes 224c of an appropriate size instead of the holes 220c in the oil pan gasket 220, and these holes 224c are formed on the outer peripheral portion 224a. Arranged obliquely inside the continuous protruding portion 224b, a remaining portion 224d is left between them.

A hole 225 for passing the pipe 209 is formed at a position corresponding to the pipe 209 connecting the oil strainer 208 and the oil pan 93. Further, a bolt passing hole 226 is formed in the outer peripheral portion 224a, and a hole 227 through which the oil relief valve 211 is passed is formed in the projecting portion 224b, similarly to the oil pan gasket 220.

With such an oil pan gasket 224, the same effects as those of the oil pan gasket 220 of the previous embodiment can be obtained, and in addition, the oil pan gasket
Even if the oil level of the lubricating oil L in the 93 moves up and down, the up and down movement is suppressed by the remaining portion 224d between the openings 224c, and the lubricating oil is supplied stably. Further, when air is present in the lubricating oil L returning to the oil pan 93, the air is released by hitting the remaining portion 224d, and then the oil pan is opened from the opening portion 224c.
As a result, the amount of air contained in the lubricating oil L in the oil pan 93 is reduced.

FIG. 10 shows a modification of the other embodiment. In this case, downward projecting ridges 224e are provided integrally with the oil pan 93 around the respective 224c on the lower surface of the oil pan 93. According to this, while the ridge 224e acts as a rib to increase the strength of the oil pan gasket 224,
When the engine 8 is operating, the lubricating oil L splashing from the oil pan 93 is prevented from splashing by the ridges 224e, making it difficult to return above the oil pan gasket 224.

[Effects of the Invention] As described above, according to the oil pan gasket of the engine of the present invention, the protrusion protruding into the oil pan by an appropriate length along the space between the joint surfaces of the crankcase and the oil pan. A part is provided over the entire circumference of the oil pan, and an opening is formed in the center part inside the protruding part, which serves both for returning the lubricating oil and for penetrating the oil strainer,
In the projecting portion, a through-hole is formed separately from the opening portion to penetrate an oil relief valve that releases the lubricating oil from the lubricating oil supply system when the pressure of the lubricating oil supply system is going to be equal to or higher than a certain value. The lubricating oil that has been lubricated returns to the oil pan through the apertures quickly and reliably, even if the engine is operated at medium and high speeds. Even if the lubricating oil in the oil pan rises along the wall surface of the oil pan with the improvement, the lubricating oil hits the protruding portion and is prevented from further rising. When the engine is operated at medium / high rotation speed and the pressure of the lubricating oil supply system is about to exceed a certain value, the oil relief valve opens to allow the lubricating oil to escape to the oil pan side. At this time, since the through-hole for penetrating the oil relief valve is formed in the projecting portion separately from the opening, the lubricating oil returning from the oil relief valve and the lubricating oil returning through the normal lubricating oil supply system And avoid interference. Further, since the lubricating oil returned from the oil relief valve is directly returned to the oil pan, the returned lubricating oil is promptly supplied from the oil strainer for lubricating oil supply. As a result, a constant amount of the lubricating oil stored in the oil pan is always maintained, and stable supply of the lubricating oil to the engine, the transmission, and the like is achieved. Further, the lubricating oil containing air bubbles during the operation of the engine and returning to the oil pan may be crushed by hitting the protruding portion, or the size of the lubricating oil may be reduced to return to the oil pan. Lubricating oil with little effect is supplied.

Further, if the relief valve penetrating through the through hole is inserted into the crankcase from below and attached, the relief valve can be easily fixed with a simple configuration.

Further, if the relief valve is arranged at the front end of the oil pan, interference with the oil strainer normally provided at the rear of the oil pan can be avoided, and effective use of space can be achieved.

Furthermore, if the opening is configured with a plurality of lubricating oil passage holes, for example, when the oil level of the lubricating oil in the oil pan moves up and down due to a change in the posture of the vehicle body, the up and down movement of the oil level Of course, the lubricating oil is prevented from splashing downward by hitting the remaining portion of the gasket between the lubricating oil passage holes in the central portion of the oil pan gasket as well as the protrusion near the outer peripheral portion of the oil pan gasket. Stable supply is possible. Even when air is mixed into the lubricating oil after lubrication, the air is released when the lubricating oil strikes the remaining gasket, and the air passes through the lubricating oil passage hole with a low air content to the oil pan. Will be back,
The amount of air contained in the lubricating oil can be reduced. Further, since a plurality of lubricating oil passage holes are provided,
Since the lubricating oil returning from the space above the oil pan gasket to the oil pan is dispersed and the flow rate of the lubricating oil passing through each passage hole is reduced, the entrapment of air when flowing into the oil pan is reduced.

[Brief description of the drawings]

FIG. 1 is an overall side view of a motorcycle to which an embodiment of the present invention is applied, FIG. 2 is a front view thereof, FIG. 3 is a partial left side view of an engine, and FIG. 5 is a longitudinal sectional view of the engine, FIG. 6 is a partial sectional plan view of the change mechanism, FIG. 7 is a view taken along line VII-VII of FIG. 4, and FIG. FIG. 9 is a plan view of the embodiment, and FIG.
FIG. 10 is a cross-sectional view showing a modification of the other embodiment. 1 ... motorcycle, 8 ... engine, 69 ... crankcase, 93 ... oil pan, 218 ... joint surface of oil pan, 219 ... joint surface of crankcase, 220, 224 ... oil pan gasket, 220b, 224b ... Projection, 220c ...
Opening, 224c ... Opening (lubricating oil passage hole).

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Sho 59-60319 (JP, U) Japanese Utility Model Sho 57-68142 (JP, U) (58) Fields surveyed (Int. Cl. ⁶ , DB name) F01M 11/00 F02F 11/00 F02F 7/00

Claims (4)

(57) [Claims] 1. An oil pan gasket interposed between joining surfaces of a crankcase and an oil pan constituting an engine to seal between the joining surfaces, wherein the oil pan gasket is arranged along the joining surface. A projection is provided over the entire circumference of the oil pan, and an opening is formed in the center of the projection inside the oil pan to return lubricating oil and penetrate the oil strainer. In the protrusion, a through-hole is formed separately from the opening, through which an oil relief valve that allows lubricating oil to escape from the lubricating oil supply system when the pressure of the lubricating oil supply system is going to become a certain value or more. An oil pan gasket for an engine. 2. The relief valve passing through the through hole,
The oil pan gasket according to claim 1, wherein the oil pan gasket is inserted into the crankcase from below and attached thereto. 3. The oil pan gasket according to claim 1, wherein the relief valve is disposed at a front end of the oil pan. 4. The oil pan gasket according to claim 1, wherein said opening portion is constituted by a plurality of lubricating oil passage holes.