JP2003239715A - Drysump type four-cycle engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a reduction of the number and weight of parts for oil circulation, an efficient use of an oil pump, a small size of an engine and simplification of oil pump piping in a drysump type four-cycle engine. <P>SOLUTION: The inside of a crank case 20 is partitioned to a crank chamber 51 at a front side and a mission chamber 52 at a rear side by a partition wall 55 having constant height. A lower part of the mission chamber 52 is made to an oil tank chamber 64 and a generator chamber 58 and a cover chamber such as a clutch chamber 59 are provided at both ends in a crank axis direction of the crank case 20. An oil escaping passage 125 for escaping an oil to the generator chamber 58 side is formed between the crank chamber 51 and the generation chamber 58. The oil in the generator chamber 58 is suctioned through an oil passage 130 or the like crossing below the crank chamber 51 and is discharged to a gas part of the clutch chamber 59 by a scavenging pump 107 disposed in the clutch chamber 59. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry sump type four-cycle engine suitable for vehicles such as riding type four-wheeled vehicles for riding on uneven terrain or two-wheeled vehicles, and more particularly to improvement of oil storage and circulation structure.

[0002]

2. Description of the Related Art In a conventional dry sump type 4-cycle engine, an oil tank is installed separately from a crankcase, a certain amount of oil is stored in the oil tank, and an oil pump is used to inject oil from the oil tank into each engine. It is configured such that the oil that has been pressure-fed to the location and dropped to the bottom of the crankcase or the oil pan is returned to the oil tank by another oil pump.

In such a structure in which the oil tank is arranged separately from the engine, the number of parts and the weight are increased, a space for arranging the oil tank and external piping between the oil tank and the engine are required, and It also increases the cost.

In contrast to the dry sump type 4-cycle engine having the above-mentioned externally installed oil tank, the applicant of the present invention has filed Japanese Patent Application Laid-Open No. 6-288466 or Japanese Patent Application Laid-Open No.
As described in Japanese Patent Laid-Open No. 135419, there is proposed an engine capable of storing a certain amount of oil in a mission chamber formed in a rear portion of a crankcase. In these engines, the suction part of the oil pump (scavenging pump) is connected to the crank chamber, the oil that falls into the crank chamber is sucked from the oil suction port at the lower end, discharged to the mission chamber, and the crank chamber is kept dry. Is configured.

Another structure in which the lower portion of the mission chamber is used as an oil tank chamber is disclosed in Japanese Patent Laid-Open No. 61-2.
There is an engine described in Japanese Patent No. 15411. In this engine, a partition wall is formed between the mission chamber and the crank chamber so that the lower part of the mission chamber serves as an oil tank chamber and the left and right cover chambers communicate with each other through an oil passage. The oil is allowed to escape, and the oil sucked from the cover chamber by the oil pump is discharged into the oil in the oil tank chamber.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The former publication, JP-A-6-288466 or JP-A-8-135419
The structure in which the oil is directly sucked from the crank chamber by the oil pump, as in the engine described in No. 3, has the following problems.

(1) In the crank chamber, pressure fluctuations are repeated as the volume changes as the piston moves up and down, but if the structure is such that oil is directly sucked from the crank chamber, the pressure fluctuations in the crank chamber result in suction force of the scavenging pump. And the suction amount of the scavenging pump fluctuates, and the suction capacity of the oil pump cannot be fully utilized.

(2) The rotation of the crank web winds up the oil at the bottom of the crank chamber, which increases the stirring resistance of the crank shaft.

(3) When the engine is stopped for a long time, the oil gradually flows back into the crank chamber.

The engine disclosed in the latter publication, Japanese Patent Laid-Open No. 61-215411, has the following problems.

(1) Since the left and right cover chambers are always communicated with each other, and a constant amount of oil remains in the entire cover chambers at all times, depending on the degree of inclination, a large amount of oil can be transferred from the cover chambers to the crank chambers. The oil may flow backwards and the crankcase may not be kept dry.

(2) Since the oil in the cover chamber is discharged into the oil in the oil tank chamber by the scavenging pump, the oil is returned to the oil tank chamber in a state where air separation is insufficient. This may cause air clogging in the feed pump.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to reduce the number of parts and weight for oil circulation in a dry sump type four-cycle engine, to efficiently use an oil pump, The objective is to increase the oil capacity, downsize the engine, and simplify the oil path in the crankcase.

[0014]

In order to solve the above-mentioned problems, the invention according to claim 1 of the present application comprises a crank chamber in the front part of the crankcase and a transmission chamber in the rear part thereof, and the crankshaft core direction of the crankcase. In a dry sump type 4-cycle engine having a cover chamber covered with a cover at each end of the engine, a partition wall having a constant height is formed between the crank chamber and the mission chamber, and the mission wall is separated from the crank chamber by the partition wall. The lower part of the chamber is used as an oil tank chamber, and an escape passage for releasing oil from the crank chamber to one cover chamber is formed on one end wall of the crank chamber in the direction of the crankshaft axis, and the other cover chamber is a sub oil tank chamber. As the oil tank chamber, the oil is connected to the oil tank chamber so that almost the same level of oil is collected, and the oil is sucked from the one cover chamber. In is provided with a scavenging pump for discharging the oil tank chamber or the other of the cover chamber.

That is, as compared with the conventional dry sump type 4 engine having an externally installed oil tank, by forming the oil tank in the engine, the number of parts and weight of the oil tank can be reduced and the oil tank can be reduced. The space for arrangement and external piping can be omitted, and the engine can be made compact and the cost can be reduced.

By utilizing the other cover chamber as the sub oil tank chamber, in the structure in which the oil tank is provided in the engine, the oil storage amount can be increased without upsizing the crankcase.

The scavenging pump does not directly suck the oil from the crank chamber, but once allows the oil to escape to one cover chamber and sucks the oil from the one cover chamber. It is possible to secure stable suction and discharge without being affected by the pressure fluctuation of No. 3, increase the amount of oil suctioned by the scavenging pump, and reliably return the oil in the crank chamber to the oil tank chamber.

Since the oil in the crank chamber is once released to one cover chamber and the oil is sucked from the cover chamber,
Since the crank web does not wind up the oil in the crank chamber, it is possible to reduce the stirring resistance due to the oil in the crank chamber.

According to a second aspect of the present invention, in the dry sump type four-cycle engine according to the first aspect, the both cover chambers are communicated by an oil passage, the scavenging pump is arranged in the other cover chamber, and the scavenging pump is arranged. By directly connecting the suction port to the end of the oil passage, the oil in one of the cover chambers is directly sucked.

As a result, the scavenging pump can be arranged compactly by utilizing the space in the other cover chamber, and the piping for the scavenging pump can be simplified. Moreover, by keeping one cover chamber communicating with the crank chamber through the escape passage in a dry state by the scavenging pump, it is possible to prevent the oil from returning to the crank chamber due to tilting or the like during operation,
It is possible to prevent a reduction in power transmission efficiency due to the resistance of oil in the crank chamber.

According to a third aspect of the present invention, in the dry sump type four-cycle engine according to the second aspect, the oil passage is formed at a position lower than a relief passage opening from the crank chamber to one of the oil chambers, and It is formed so as to cross the lower side of the crank chamber.

As a result, the effect of preventing oil backflow to the crank chamber is increased, and the dry state of the crank chamber is not impaired.

Further, the space below the crank chamber can be effectively used as an oil passage.

According to a fourth aspect of the present invention, in the dry sump type four-cycle engine according to the third aspect, the oil passage is integrally formed with the crankcase.

This makes it possible to save the piping parts of the scavenging pump.

According to a fifth aspect of the present invention, in the dry sump type four-cycle engine according to any one of the first to fourth aspects, the scavenging pump arranged in the other cover chamber in which oil is stored has the other cover. It is sealed so that oil does not flow back from the chamber to one cover chamber.

This prevents the oil from flowing back from the other cover chamber to the one cover chamber even when the engine is stopped for a long time, and keeps the oil level in the other oil chamber, so that the oil can be detected during oil detection. Accurate oil level can be measured.

According to a sixth aspect of the present invention, in the dry sump type four-cycle engine according to any of the first to fifth aspects, a generator is housed in one cover chamber that communicates with the crank chamber and communicates with the oil tank chamber. A clutch is stored in the other cover chamber.

The dead space below the clutch can be effectively utilized for scavenging pump placement.

According to a seventh aspect of the present invention, in the dry sump type four-cycle engine according to any one of the first to sixth aspects, each transmission gear of the transmission is arranged at a height that does not submerge in oil in the oil tank chamber, The mission room is equipped with an oil shower that drops oil toward the transmission gears.

Thus, the lower part of the transmission chamber is effectively used as an oil tank chamber, and while maintaining the lubrication of the transmission gear, there is no agitation resistance of the oil to the transmission gear, and a reduction in power transmission efficiency is prevented. You can

According to an eighth aspect of the present invention, in the dry sump type four-cycle engine according to the sixth or seventh aspect, a clutch device arranged in the other cover chamber is provided.
It is placed at a height that does not soak in oil.

As a result, the resistance of the oil to the rotation of the clutch is eliminated, and the reduction of power transmission efficiency can be prevented.

According to a ninth aspect of the present invention, in the dry sump type four-cycle engine according to any of the second to eighth aspects, the discharge portion of the scavenging pump is located above the oil level in the other cover chamber. The oil is released into the gas.

As a result, the oil sucked by the scavenging pump can be separated into gas and liquid, and only the liquid can be pumped up into the cover chamber or the like.

According to a tenth aspect of the present invention, in the dry sump type four-cycle engine according to any of the second to ninth aspects, a plate-shaped filter is arranged in the oil passage.

As a result, the space for arranging the filter can be saved, and since the plate-shaped filter is used, the filter can be easily attached and detached.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION [Vehicle on which Engine is Mounted] FIG. 1 shows a four-wheeled vehicle for riding on rough terrain equipped with a dry sump type single cylinder four-cycle engine to which the present invention is applied. The frame 1 is provided with a pair of left and right front wheels 2 at its front portion, and a rear portion is provided with a pair of left and right rear wheels 5 via a swing arm 4, and the swing arm 4 is elastically supported by a shock absorber 3. An engine 7, a radiator 8 and the like are mounted in the body frame 1, and a riding type seat 10, a fuel tank 11, a bar-shaped handle 12 and the like are provided on an upper portion of the body frame 1.

In the engine 7, a cylinder 21, a cylinder head 22 and a head cover 23 are sequentially fastened on a crank case 20, an exhaust pipe 24 is connected to the front exhaust port of the cylinder head 22, and the exhaust pipe 24 is connected to the exhaust pipe 24. It curves to the right, extends rearward, and is connected to the muffler 25. An intake pipe 26 is connected to a rear intake port of the cylinder head 21, and the intake pipe 26 includes a carburetor 27, an intake duct 28, and an element 29 in a rear air cleaner box 30.
Connected to.

The vehicle employs a chain drive system, and a drive chain 34 is wound between the output sprocket 31 of the engine 7 and the sprocket 33 of the rear axle 32.
The rear chain 5 is driven by the drive chain 34. In FIG. 1, reference numerals O1, O2, and O3 denote the engine 7 respectively.
3 shows the crank shaft core, the shift input shaft core, and the shift output shaft core.

[Engine Outer Shell] FIG. 2 is an expanded view of the II-II cross section of FIG. 1, showing a plane passing through the cylinder center line C, the crank shaft core O1, the shift input shaft O2 and the shift output shaft O3. It is the figure which cut | disconnected the engine 7 and developed. In FIG. 2, the crankcase 20 is divided into two left and right crankcase members 20a and 20b, and both crankcase members 20a and 20b have a mating surface that is orthogonal to the crankshaft axis O1 and passes through the cylinder center line C. Are combined as. In the crankcase 20, the front part is a crank chamber 51 for housing the crankshaft 41, and the rear part is a mission chamber 52 for housing the mission M.

Left and right end walls 53, 54 of the crankcase 20
Crankcase covers 56 and 57 are fastened to the respective crankcases, and a generator 60 is housed in a cover chamber 58 covered by the left crankcase cover 56, and a generator chamber 60 is housed in a cover chamber 59 covered by the right crankcase cover 57. Contains a multi-plate friction clutch 61.

Left and right crankcase covers 56, 57
In order to clearly distinguish the cover chambers 58 and 59 from each other, the left side crankcase cover 56 and the cover chamber 58 are referred to as a generator cover and a generator chamber, and the right side crankcase cover 57 is named according to the names of the devices to be housed therein.
The cover chamber 59 and the cover chamber 59 are referred to as a clutch cover and a clutch chamber, and will be described below.

[Power transmission system] The crankshaft 41 is rotatably supported by the left and right end walls 53 and 54 of the crankcase 20 via bearings 65 and 65, and has a left and right divided structure. The left and right crankshaft parts are connected. The left end portion of the crankshaft 41 projects into the generator chamber 58 to form a cam chain sprocket 68, and a starting gear 84 and a rotor (flyhole) 70 of the generator 60 are attached. The cam chain 71 wound around the cam chain sprocket 68 is a cam chain tunnel 62 formed in the cylinder 21 and the cylinder head 22.
Passes through the inside of the head cover 23 and is wound around the sprocket 72 of the cam shaft 48.

The right end of the crankshaft 41 is a clutch chamber 59.
A balancer drive gear 83 and a crank gear 82 that protrudes inward and meshes with the clutch gear 81 of the clutch 61 are fixed.

The transmission M has a structure in which it can be switched between five forward gears and one reverse gear. The speed change input shaft 42 is provided with a pair of left and right bearings 73, and left and right end walls 53, 5 of the crankcase 20.
4 is supported on the shift input shaft 42, and from the right side, the input-side forward shift gears 85 for forward 1st speed, 5th speed, 3rd speed, 2nd speed, and 4th speed are mounted in order from the right side, and the input gear is input to the left end. A side-reverse shift gear 86 is provided. The right end of the shift input shaft 42 projects into the clutch chamber 59 and is connected to the hub of the clutch 61.

The variable speed output shaft 43 has a pair of left and right bearings 74
The crankcase 20 is supported by the left and right end walls 53, 54 of the crankcase 20, the left end portion thereof protrudes leftward from the mission chamber 52, and the output sprocket 31 for driving the rear wheels is fixed. On the speed change output shaft 43, forward movement 1
Output side forward transmission gears 87 for the fifth, fifth, third, second and fourth speeds are mounted, and the output side reverse transmission gear 8 is provided at the left end portion.
8 are provided. The output-side forward transmission gears 87 mesh with the input-side forward transmission gears 85, respectively, and the output-side reverse transmission gear 88 includes a reverse idle gear 90 provided on the reverse idle shaft 44, as shown in FIG. It meshes with the input-side reverse transmission gear 86 through.

FIG. 8 shows the arrangement of shafts and gears in the engine. Below the mission chamber 52, a shift rod 45, a change drum 46, a change shaft 47, etc. are arranged. Only one shift rod 45 is provided, and a plurality of (for example, three) shift forks 76 are supported by the one shift rod 45, and each shift fork 76 extends to the shift input shaft 42 and the shift output shaft 43, respectively. It engages in the groove of the shift sleeve. The change shaft 47 is provided with a swing arm 77 for rotating the change drum 46 at a predetermined pitch.

A balancer shaft 50 is provided in front of the crankshaft 41.
The balancer gear 91 of the balancer shaft 50 meshes with the balancer drive gear 83 of the crankshaft 41. Above the transmission input shaft 42, a large and small intermediate gear 9 for starting is provided.
3, 94 are provided coaxially and a starting motor 95 is arranged. The large starting intermediate gear 93 is a starting motor 95.
Small pinion intermediate gear 94 that meshes with the pinion 96 of
Engages with the starting gear 84 of the crankshaft 41 via the front idle gear 97.

FIG. 15 shows the balancer shaft 50 and the starting mechanism in detail. The balancer shaft 50 is rotatably supported by the left and right end walls 53 and 54 of the crankcase 20 via bearings 75, and is arranged in the axial direction. Weights 7 at the center and both left and right ends
8, 79 and 80 are provided. The center weight 78 is disposed between the crank webs (weight portions) 49 of the crankshaft 41, the left weight 79 is disposed in the generator chamber 58, and is positioned substantially opposite to the cam chain sprocket 68, and the right weight is disposed. 80 is the clutch chamber 5
It is formed integrally with the balancer gear (scissors gear) 91 in 9. A water pump 98 is provided at the right end of the balancer shaft 50.
Pump shaft 99 is linked and coupled via a joint.

The gears 93, 94, 97 of the starting mechanism are arranged above the generator chamber 58, and the starting motor 9
5 is attached to the upper wall of the crankcase 20.

[Structure of Each Lubrication Point] In FIG. 2, an oil passage 111 communicating with the oil supply passage 110 in the clutch cover 57 is formed in the crankshaft 41, and the oil passage 111 is the outer periphery of the crankpin 37. It passes through the fitting portion and the crank pin 37 to reach the fitting portion of the connecting rod 38. The oil passage 110 in the clutch cover 57 communicates with the outlet portion 115a of the secondary filter 115 attached to the clutch cover 57.

Oil passages 118 and 119 are formed in the shift input shaft 42 and the shift output shaft 43, respectively.
The oil passages 118, 119 communicate with the oil chamber 120 formed in the left end wall 53 of the crankcase 20, respectively, and reach the fitting portions of the transmission gears 85, 86, 87, 88 and the clutch gear 81. Further, the head cover 23 is also formed with an oil passage 121 for lubricating the sliding contact portion of the cam shaft 48.

FIG. 14 is a sectional view taken along line XIV-XIV of FIG.
Above the meshing portion of the transmission gear 85 and the like, the transmission input shaft 42 is provided.
An oil shower pipe 126 is installed in parallel with the above, and the inside of the oil shower pipe 126 communicates with an oil chamber 120 formed in the left end wall 53 of the crankcase. The oil shower pipe 126 is formed with a plurality of nozzles 127 at intervals in the axial direction, and the oil is ejected from each nozzle 127 toward the gear meshing portion.

[Oil Storage Structure in Crankcase] FIG. 3 shows the inner surface of the left crankcase member 20a, and a partition wall 55 having a constant height is provided between the front crank chamber 51 and the rear mission chamber 52. Is formed integrally with the crankcase 20, and the partition wall 55 forms the lower portion of the mission chamber 52 into an oil tank chamber 64 isolated from the crank chamber 51. The partition wall 55 is formed at substantially the same height as the crank shaft core O1, extends forward and downward along the outer shape of the crank web (including the crank weight portion) 49, and is located substantially directly below the crank shaft core O1. The oil tank chamber 64 is extended to a position below the crank chamber 51. The lower portion of the crank chamber 51 is surrounded by a bottom wall 102 that connects the front lower end of the partition wall 55 (intersection with the partition wall 101) to the front, and the bottom wall 102 reaches a position below the front balancer shaft 50. Further, it extends to the front upper end of the crank chamber 51 along the outer periphery of the center weight 78 of the balancer shaft 50.

The shift input shaft 42, the shift output shaft 43 and the reverse drive idle shaft 44 are arranged such that their axes O2, O3 and O4 are all higher than the crank axis O1. With respect to the oil (level L1), almost none of the transmission gear groups (85, 87, 90, etc.) mounted on the transmission shafts 42, 43, 44 are immersed in the oil as shown in FIG. . As a result, the resistance of oil to the transmission gear group is eliminated, and the reduction of power transmission efficiency is prevented.

FIG. 10 is a partial sectional view taken along the line XX of FIG. 3, in which the right end wall of the oil tank chamber 64 (the crankcase right end wall) 5
4 is formed with a communication hole 105 for communicating the oil tank chamber 64 and the clutch chamber 59 at a position lower than the oil level L1. As a result, the oil of the same level L1 as the oil tank chamber 64 is stored in the clutch chamber 59. The clutch chamber 59 is stored and can be used as an extension of the oil tank chamber 64. Further, the clutch 61 arranged in the clutch chamber 59 is installed at a height such that the lower end portion thereof is not soaked in oil. This eliminates the resistance of the oil to the clutch 61 and prevents the reduction of power transmission efficiency.

FIG. 9 is a sectional view taken along the line IX-IX in FIG. 3, in which the feed pump 106 and the scavenging pump 107 are coaxially arranged in the clutch chamber 59.
The arrangement height of 07 is the rotor 10 of the pumps 106 and 107.
6a and 107a are set so as to be substantially within the oil level L1. In order to prevent oil from overflowing from the clutch chamber 59 into the crank chamber 51, the insert 65a supporting the bearing 65 on the right side of the crankshaft 41 is provided with the bearing 65.
It is shaped to seal the lower half. That is, FIG.
As shown in FIG. 7, the inner peripheral shape of the insert 65a is formed such that the upper half is formed in a semicircular shape and the lower half is higher in a weir shape than the circumference of the upper half.

On the left end wall 53 of the crank chamber 51 (the crankcase left end wall) 53, an oil escape passage 125 is formed which is substantially flush with the bottom of the crank chamber 51. The oil escape passage 125 is open to the generator chamber 58, and the opening is formed at a high position having a step D with respect to the lower end wall 58a of the generator chamber 58. As a result, oil can be released from the crank chamber 51 to the generator chamber 58 by natural fall or flow, but the oil does not return from the generator chamber 58 to the crank chamber 51.

Below the bottom wall 102 of the crank chamber 51,
A pair of oil passages 130, 1 parallel to the crankshaft axis O1
31 is provided in parallel with the crankcase 20. The left end of one oil passage 130 is opened to the generator chamber 58 and the right end thereof is closed, and the other oil passage 131 is formed.
Has its left end closed and its right end opened toward the clutch chamber 59 at a position below the oil level L1. Between the oil passages 130 and 131, the left half is the partition wall 1.
The third half filter 13 is separated by 33 and has a plate-shaped right half.
It communicates through 5. That is, the left generator chamber 58 and the right clutch chamber 59 are communicated with each other via the oil passages 130 and 131 and the plate-shaped tertiary filter 135. The left end opening 130a of the one oil passage 130 is located below the oil escape passage 125 of the crank chamber 51 with a step D, and is set at the same height as the lower end wall 58a of the generator chamber 58. ing. As a result, the crank chamber 51 to the generator chamber 5
The oil flowing into the oil passage 8 quickly flows into the oil passage 130.

As shown in FIG. 3, one of the oil passages, that is, the upstream oil passage 130 has a cross-sectional shape of an approximately isosceles triangle, and the other oil passage, that is, the downstream oil passage 131, has an upstream oil passage. It is located at the lower rear portion of the passage 130 and has a cross-sectional shape formed into a substantially right triangle. Partition wall 133 separating both oil passages 130, 131
Is formed in a rearwardly inclined shape, and as shown in FIG. 5, the plate-shaped tertiary filter 135 is also arranged in a rearwardly inclined shape like the partition wall 133, thereby increasing the filtration area.

FIG. 4 shows the outer surface of the left crankcase member 20a, and the oil escape passages 125 opening to the generator chamber 58 are formed at three locations. In the case of the present embodiment, a position substantially directly below the crank shaft core O1,
It is formed at a position slightly rearward of the position immediately below and substantially directly below the balancer shaft center O5. The sub oil tank chamber 1 is provided below the generator chamber 58 via a partition wall 140.
41 is formed, and the sub oil tank chamber 141 communicates with the oil tank chamber 64 via the oil communication passage 142 at the lower end portion as shown in FIG. 3, and the oil is at the same level L1 as the oil tank chamber 64. Can be stored.

FIG. 6 is a side view showing the outer surface of the right crankcase member 20b. Inside the clutch chamber 59, the weir 1 that covers the lower rear portion of the balancer gear (scissors gear) 91 is shown.
45 is formed integrally with the crankcase 20, so that a fixed amount of oil can be retained in the lower half of the balancer gear 91. A small hole 145a is formed at the lower end of the weir 145.

[Overall Structure of Oil Pump] XII-XI in FIG.
Referring to FIG. 12 showing the I cross section, as an oil pump, as described above, a feed pump 106 that pumps oil from the oil tank chamber 64 to each lubrication point of the engine, and oil that is sucked from the generator chamber 58 and pumped into the clutch chamber 59. A scavenging pump 107 is arranged in the clutch chamber 59 and attached to the clutch cover 57, and both pumps 106 and 107 are trochoid pumps including inner and outer rotors.

The outer contours of both pumps 106 and 107 are composed of a clutch cover 57, a pump housing 151 and a pump cover 153.
51 is fastened to the inner surface of the clutch cover 57, and the pump cover 153 is fastened to the left end surface of the pump housing 151 via an O-ring 152. The rotor 106a for the feed pump is the pump chamber 10 in the clutch cover 57.
6b, rotor 10 for scavenging pump
7a is disposed in the pump chamber 107b in the pump housing 151, and the rotors 106a,
107a is fixed to the same pump shaft 155. The common pump shaft 155 is supported by the pump housing 151 and the pump cover 153, protrudes into the clutch chamber 59 through the pump cover 153, and the pump gear 156 is fixed to the protruding portion. The pump gear 156 meshes with the crank gear 82 of the crankshaft 41.

[Structure of Scavenging Pump] XI of FIG.
13, the suction portion (suction passage) 159 of the scavenging pump 107 opens at the left end surface of the pump cover 153, and the opening portion is an O-ring 161.
Is connected to the downstream oil passage 131 of the right crankcase member 20b. The discharge part 160 of the scavenging pump 107 has a discharge pipe 16 for discharging backward.
2 is formed integrally with the pump housing 151, and a rubber hose 163 is connected to the discharge pipe 162. The rubber hose 163 extends rearward and upward in the clutch chamber 59, is inserted into the oil discharge chamber 165 surrounded by the end wall of the clutch cover 57 and the gasket 164, and opens toward the end wall of the clutch cover 57. That is, the rubber hose 163 discharges the oil into the air higher than the oil level L1 in the clutch chamber 59 and collides it with the inner surface of the clutch cover 57 to separate the gas and liquid, and the clutch chamber 5
It is designed to store oil in 9. The gasket 164 is a gasket sandwiched between the clutch case 57 and the right end surface of the right crankcase member 20b.

As a measure to prevent oil from entering the scavenging pump 107 from the clutch chamber 59,
With the O-rings 152 and 161 described above, the pump housing 15
In addition to the structure in which the mating surfaces of 1, the pump cover 153 and the crankcase 20 are sealed, both the axially opposite sides of the rotor 107a for the scavenging pump, the fitting portion between the pump shaft 155 and the pump cover 153, and The rotary seal member 1 is fitted to the fitting portion with the pump housing 151.
70 and 171 are fitted.

[Structure of Feed Pump] In FIG. 12, the suction portion 174 of the feed pump is opened leftward through an oil chamber 175 in the pump housing 151 and a suction hole 176 in the pump cover 153. The suction hole 176 is connected to an oil intake passage 178 formed at the bottom of the oil tank chamber 64 via an O-ring 177. The oil intake passage 178 communicates with an upper oil intake chamber 180 formed at the bottom of the oil tank chamber 64, and the upper oil intake chamber 180 is connected to the lower oil through a plate-shaped primary filter 182 arranged substantially horizontally. The lower oil intake chamber 181 communicates with the intake chamber 181, and the lower oil intake chamber 181 communicates with the oil tank chamber 64 via an oil hole 183. Further, as described above, the oil communication passage 14 is provided in the lower oil intake chamber 181.
The sub-oil tank chamber 141 communicates with each other via 2.

A relief valve 200 is provided in the oil chamber 175 on the suction side of the feed pump 106. When the discharge pressure of the feed pump 106 rises above a set value, the relief valve 200 opens and the oil in the discharge part 173 is discharged. Is partially returned to the suction side oil chamber 175 via the oil return passage 206 and the relief valve 200.

The relief valve 200 has a bottomed cylindrical valve case 201, a cylindrical plunger 202 slidably fitted in the valve case 201, and a valve spring 203 for urging the plunger 202 to a closed position. It consists of The valve case 201 is fixed to the pump housing 151 and the like so as to traverse the oil chamber 175 left and right, and a plurality of oil return holes 205 opening to the oil chamber 175 are circumferentially spaced on the peripheral wall of the valve case 201. Has been formed. Right end wall of plunger 202 (pressure receiving wall)
Is an opening 201 formed in the right end wall of the valve case 201.
It faces the oil return passage 206 via a. The plunger 202 is urged rightward by the valve spring 203 to close the oil return hole 205. That is, when the discharge pressure of the feed pump 106 rises, the plunger 202 moves to the left against the valve spring 203, and when the discharge pressure exceeds a predetermined value, the oil return hole 205 opens and a part of the discharged oil is discharged. Oil chamber 175 on the oil suction side
It is supposed to return to. In FIG. 12, although the relief valve 200 seems to block the oil chamber 175, the oil chamber 175 is formed widely so as to surround the relief valve 200, regardless of whether the relief valve 200 is opened or closed. The suction portion 174 and the suction hole 176 are always kept in communication with each other.

The discharge portion 173 of the feed pump 106 communicates with the oil supply passage 210 in the clutch cover 57,
The oil supply passage 210 opens toward the inside of the clutch chamber 59, and an oil supply pipe 212 is connected to the opening through a connecting fitting 213.

[Oil Supply System Path] FIG. 7 shows a state in which both oil pump assemblies are assembled on the inner surface of the clutch cover 57. As described above, the oil supply pipe 212 communicating with the discharge side of the feed pump 106 is shown. Extends upward in the clutch chamber 59 and is connected to the inlet of the secondary filter 115. An oil supply passage 220 extending forward and an oil supply passage 110 for the crankshaft extending downward communicate with the outlet 115a of the secondary filter 115.

Both oil supply passages 220 and 110 are shown in FIG.
As described above, the oil supply passage 110 is formed on the mating surface with the right crankcase member 20b and extends downward.
Communicates with the oil passage 111 in the crankshaft 41 of FIG. 2 as described above. On the other hand, the oil supply passage 220 extending forward in FIG. 6 communicates with the oil supply passage 223 parallel to the crankshaft axis direction at the front end, traverses the inside of the crankcase 20, and reaches the left end of the crankcase.

In FIG. 4, the oil supply passage 223 penetrating from the right to the left in the crankcase 20 is open to the generator chamber 58, and two oil supply passages are provided in the opening as shown in FIG. The pipes 240 and 241 are connected in a two-stage stack.

One oil supply pipe 240 passes through the upper cam chain tunnel 62 and is connected to the oil connection port 243 of the cylinder head 22, and as shown in FIG. 18, passes through the oil supply passage 245 in the cylinder head 22 and the head cover. It reaches the cam shaft 48 in 23. The other oil pipe 241 extends rearward and extends from the oil chamber 120 of FIG. 2 to the oil passage 118 of the speed change input shaft 42 and the speed change output shaft 4.
3 to the oil passage 119.

[0076]

[Oil Supply from Feed Pump to Each Lubrication Point] Since it has already been described in detail, here, based on the block diagram showing the oil circulation path of FIG. 19, the flow of oil by the feed pump 106 will be described. A brief description will be given with reference to FIG. 16, which shows the flow of oil by the scavenging pump 107, and FIG. 18 which shows the flow of oil and the return of oil to each lubrication point. 19, the oil sucked into the feed pump 106 from the oil tank chamber 64 through the plate-shaped primary filter 182 while the engine is operating enters the secondary filter 115 through the oil supply pipe 212 and the like and is filtered. After that, the oil is branched into two oil supply passages 220 and 110.

One of the oil supply passages 110 supplies oil to the crankshaft 41, and lubricates around the crankshaft, such as around the crank pin portion and the piston.

The other oil supply passage 220 is branched into two oil supply pipes 240 and 241. One oil supply pipe 241 supplies oil to the speed change input shaft 42 and the speed change output shaft 43 and is fitted in each speed change gear. At the same time as lubricating the engagement portion, oil is supplied to the oil shower pipe 126 to lubricate the engagement portion of the transmission gear group. The other oil supply pipe 240 lubricates the cam shaft and the like around the cylinder head 22.

[Other Lubricating Parts] In FIG. 6, the balancer gear (scissor gear) 91 provided in the clutch chamber 59 lubricates the meshing portion by scraping the oil in the clutch chamber 59 by itself. In addition, FIG.
The pump gear 156 also lubricates the meshing portion with the crank gear 82 by the oil in the clutch chamber 59 that is lifted up by itself.

[Return of Oil from Each Lubrication Point to Oil Pump Chamber] In FIG. 2, the oil used for lubricating the cam shaft 48 falls or flows down to the generator chamber 58 through the chain tunnel 62. The oil supplied around the crankshaft falls or flows down to the bottom of the crank chamber 51. The oil used to lubricate the mission M directly drops or flows down to the oil tank chamber 64 below the mission chamber.

In FIG. 9, the oil that has dropped to the bottom of the crank chamber 51 gathers at the bottom of the generator chamber 58 by dropping or flowing from the oil escape passage 125 of the left end wall 53 of the crankcase, and by the suction force of the scavenging pump 107. Through the oil passage 130, the tertiary filter 135 and the oil passage 131 below the crank chamber, the crank case 20 is crossed left and right, and the scavenging pump 107 is directly sucked from the oil passage 131.

The oil thus returning to the crank chamber 51 escapes from the oil escape passage 125 formed on the side of the crank web 49 to the generator chamber 58, and is sucked from the generator chamber 58 by the scavenging pump 107 to obtain the clutch chamber. When it is returned to 59, the pressure fluctuation in the crank chamber 51 does not affect the suction force of the scavenging pump 107, and the oil winding phenomenon due to the rotation of the crank web 49 does not occur. The performance of the scavenging pump 107 can be utilized without waste, and the required suction amount can be secured without increasing the size of the scavenging pump 107.

In FIG. 13, the scavenging pump 1
The oil directly sucked into 07 is pressurized, then sent through the discharge pipe 163 to the upper rear, and in the discharge chamber 165 formed above the oil level L1,
It is discharged toward the end wall of the clutch cover 57. At this time, the oil is separated into gas and liquid, and the liquid portion (oil) is collected in the lower part of the clutch chamber 59 and returned to the oil tank chamber 64 through the communication hole 105 as shown in FIG. Be stored. Further, the oil is also accumulated in the sub oil tank chamber 141 at the lower rear portion of the generator chamber via the oil communication passage 142 of FIG.

When the engine is stopped for a long time, the scavenging pump 107 has the seals 170, 171 and various O-rings 15 on both sides of the pump shaft as shown in FIG.
Since it is sealed with 2, 161, the oil tank chamber 6
4 and the oil in the clutch chamber 59 do not flow back to the generator chamber 58 and the crank chamber 51 via the scavenging pump 107, the crank chamber 51 can be kept in a dry state, and the clutch chamber 59 and the oil tank chamber 6
The oil level in 4 can be kept constant.
As a result, the amount of oil in the oil tank chamber 64 can be accurately detected even after the engine has been stopped for a long time. Further, even during engine operation, the generator chamber 58
Is kept in a dry state by the scavenging pump 107, and the oil passages 130 and 131 are formed below the escape passage 125 with a step difference therebetween, so that the oil flows back to the crank chamber due to the inclination and vibration. There is nothing to do.

[0085]

[Other Embodiments of the Invention] (1) Out of the left and right cover chambers, that is, the generator chamber and the clutch chamber, the oil is once released from the crank chamber to the clutch chamber, and then the scavenging pump sucks the oil from the clutch chamber. It is also possible to adopt a structure in which it is returned to the oil tank chamber.

[0086]

As described above, the present invention has the following advantages. (1) In the dry sump type 4-cycle engine, a partition wall having a constant height is formed between the crank chamber and the mission chamber to form an oil tank chamber below the mission chamber. Compared to a dry sump type 4 engine equipped with an oil tank, by forming an oil tank in the engine, the number of parts and weight for the oil tank can be reduced, and the space for arranging the oil tank and external piping can be omitted, A compact engine and cost reduction can be achieved.

(2) By utilizing the other cover chamber as the sub oil tank chamber, in the structure in which the oil tank is provided in the engine, the oil storage amount can be increased without enlarging the crankcase.

(3) The scavenging pump does not directly suck the oil from the crank chamber, but once allows the oil to escape to one cover chamber and sucks the oil from the one cover chamber. Is not affected by the pressure fluctuation in the crank chamber, stable suction and discharge can be secured, the amount of oil suctioned by the scavenging pump is increased, and the oil in the crank chamber can be reliably returned to the oil tank chamber.

(4) Since the oil in the crank chamber is once released to one cover chamber and the oil is sucked from the cover chamber, the crank web does not wind up the oil in the crank chamber and the stirring resistance by the oil is reduced. be able to.

(5) Both cover chambers are connected by an oil passage, the scavenging pump is arranged in the other cover chamber, and the suction port of the scavenging pump is directly connected to the end of the oil passage so that one cover If the oil in the chamber is directly sucked in, the space in the other cover chamber can be used to place the scavenging pump compactly, the piping for the scavenging pump can be simplified, and the escape passage to the crank chamber One of the cover chambers that communicate with each other via a scavenging pump is kept in a dry state to prevent the oil from returning to the crank chamber due to tilting, etc. It is possible to prevent a decrease in power transmission efficiency due to.

(6) If the oil passage is formed at a position lower than the escape passage opening from the crank chamber to one of the oil chambers, and is formed so as to traverse the lower side of the crank chamber, The effect of preventing oil backflow is increased, the dry state of the crank chamber is not impaired, and the reduction of power transmission efficiency due to oil resistance can be prevented. Further, the space below the crank chamber can be effectively used as an oil passage.

(7) By integrally molding the oil passage formed under the crank chamber with the crankcase,
Saves piping parts for scavenging pumps.

(8) If the scavenging pump arranged in the other cover chamber where the oil is stored is sealed from the other cover chamber, the oil will not flow from the other cover chamber even when the engine is stopped for a long time. Can be prevented from flowing backward, and by maintaining the oil level in the other oil chamber, it is possible to accurately measure the oil level during oil detection.

(9) When the generator is housed in one cover chamber that communicates with the crank chamber and the clutch is housed in the other cover chamber that communicates with the oil tank chamber, the dead space below the clutch is located in the scavenging pump. Can be effectively used for.

(10) Each transmission gear of the mission is arranged at a height that does not submerge in the oil in the oil tank chamber, and an oil shower is provided in the mission chamber to drop the oil toward the transmission gear. Is effectively used as the oil tank chamber, and while maintaining the lubrication of the transmission gear, there is no agitation resistance of the oil to the transmission gear, and it is possible to prevent a reduction in power transmission efficiency.

(11) If the clutch device disposed in the other cover chamber is disposed at a height that does not allow it to be immersed in oil,
The oil resistance against the rotation of the clutch is eliminated, and the reduction of power transmission efficiency can be prevented.

(12) If the discharge portion of the scavenging pump is positioned above the oil level in the other cover chamber to release the oil into the gas, the oil sucked by the scavenging pump will be discharged. It is possible to separate the liquid and pump only the liquid into the cover chamber or the like.

(13) When the plate-shaped filter is arranged in the oil passage, the space for arranging the filter can be saved, and since the plate-shaped filter is used, the filter can be easily attached and detached.

[Brief description of drawings]

FIG. 1 is a side view of a riding type all-terrain vehicle for four-wheeled vehicle equipped with a dry sump type four-cycle engine according to the present invention.

FIG. 2 is a II-II cross sectional enlarged development view of the engine shown in FIG.

FIG. 3 is an inside view (right side view) inside the left crankcase member.

FIG. 4 is an external view (left side view) inside the left crankcase member.

FIG. 5 is an inside view (left side view) inside the right crankcase member.

FIG. 6 is an external view (right side view) inside the right crankcase member.

FIG. 7 is an inside view (left side view) of the clutch cover.

FIG. 8 is a right side view showing the arrangement of various shafts and gears in the engine.

9 is a schematic cross-sectional view taken along the line IX-IX of FIG.

10 is a schematic cross-sectional view taken along line XX of FIG.

11 is a sectional view taken along line XI-XI of FIG.

12 is a sectional view taken along line XII-XII of FIG.

13 is a sectional view taken along line XIII-XIII in FIG.

14 is a sectional view taken along line XIV-XIV in FIG.

15 is a sectional view taken along line XV-XV in FIG.

FIG. 16 is a schematic diagram of piping in the engine showing the flow of oil by the feed pump.

FIG. 17 is a schematic diagram of piping in the engine showing the flow of oil by the scavenging pump.

FIG. 18 is a schematic diagram of piping in the engine showing oil supply to each lubrication point and oil return.

FIG. 19 is a block diagram showing the flow of the entire oil in the engine.

[Explanation of symbols]

20 Crank Case 21 Cylinder 22 Cylinder Head 23 Head Cover 41 Crank Shaft 42 Speed Change Effective Shaft 43 Speed Change Output Shaft 49 Crank Web 51 Crank Chamber 52 Mission Chamber 53, 54 Crank Case End Wall 55 Partition Wall 56 Generator Cover (An Example of Crank Case Cover) 57 clutch cover (an example of a crankcase cover) 58 generator chamber (an example of a cover chamber) 59 clutch chamber (an example of a cover chamber) 60 generator 61 clutch 64 oil tank chamber 85, 86, 87, 88, 90 transmission gear 102 crank chamber Bottom wall 105 Communication hole 106 Feed pump 107 Scavenging pump 125 Oil escape passage

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3G013 AA02 AB02 BA06 BB05 BB19                 3G015 AA02 AB02 BC02 BC03 CA06

Claims (10)

[Claims] 1. A dry sump type four-cycle engine in which a crank chamber is provided in a front portion of a crankcase, a mission chamber is provided in a rear portion thereof, and a cover chamber covered with a cover is provided at each end of the crankcase in a crankshaft axis direction. , A partition wall with a certain height is formed between the crank chamber and the mission chamber, and the lower part of the mission chamber separated from the crank chamber by the partition wall is the oil tank chamber Forms an escape passage for releasing oil from the crank chamber to one of the cover chambers, and the other cover chamber is a sub-oil tank chamber that communicates with the oil tank chamber so that oil at approximately the same level as the oil tank chamber accumulates. , A scavenging pump that sucks oil from the one cover chamber and discharges it to the oil tank chamber or the other cover chamber. Dry sump type 4-cycle engine, characterized in that are provided. 2. The two cover chambers are communicated with each other through an oil passage, the scavenging pump is arranged in the other cover chamber, and the suction port of the scavenging pump is directly connected to an end portion of the oil passage, whereby one cover is provided. The dry sump type four-cycle engine according to claim 1, wherein the oil in the chamber is directly sucked. 3. The oil passage is formed below the escape passage opening from the crank chamber to the one cover chamber, and is formed so as to cross the lower side of the crank chamber. The dry sump type four-cycle engine according to claim 2. 4. The dry sump type four-cycle engine according to claim 3, wherein the oil passage is formed integrally with the crankcase. 5. The scavenging pump arranged in the other cover chamber in which oil is stored is sealed so that the oil does not flow backward from the other cover chamber. Dry sump type 4-cycle engine described in Crab. 6. The generator is housed in one cover chamber that communicates with the crank chamber, and the clutch is housed in the other cover chamber that communicates with the oil tank chamber. The dry sump type 4-cycle engine described in. 7. The transmission gears of the transmission are arranged at a height not submerged in the oil in the oil tank chamber, and the mission chamber is provided with an oil shower for descending the oil toward the transmission gears. A dry sump type 4-cycle engine according to any one of claims 1 to 6. 8. The dry sump type four-cycle engine according to claim 6 or 7, wherein the clutch device arranged in the other cover chamber is arranged at a height such that it is not immersed in oil. 9. The discharge part of the scavenging pump is located above the oil level in the other cover chamber and discharges oil into the gas. Dry sump type 4-cycle engine described in Crab. 10. The dry sump type four-cycle engine according to claim 2, wherein a plate-shaped filter is arranged in the oil passage.