JP2000120419A - Two-cycle engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To comparatively easily increase a delivery quantity of an oil pump by arranging a mechanism for switching a relative rotational position of a pump lever and a delivery quantity changing rotary shaft of the oil pump. SOLUTION: A rotary shaft side lever 91 is fixed to a cam rotary shaft of an oil pump 52, and a steady cutout 92 and a quantity increasing cutout 93 are formed to be indirectly fixed to the cam rotary shaft. A pump lever 96 is rotatably installed. An engaging projection 97 exists on the pump lever 96 to be always energized to the rotary shaft side lever 91 side by a return spring. The engaging projection 97 selectively engages with either of the steady cutout 92 and the quantity increasing cutout 93 of the cam rotary shaft. An operation knob 99 threadedly engages with the pump lever 96, and the engaging projection 97 of the pump lever 96 is engaged with the steady cutout 92 or the quantity increasing cutout 93 in a switching system by operating this to switch a relative rotational position of the pump lever 96 and the cam rotary shaft to fix the relative rotational position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-stroke engine mounted on an outboard motor or the like.

[0002]

2. Description of the Related Art Conventionally, in a two-cycle engine,
Fuel mixed with lubricating oil is supplied into the crankcase. Then, during the running-in period (for example, 1
(0 hour), the amount of lubricating oil mixed with the fuel is increased. In this way, the crank chamber is lubricated.

[0003]

In recent years, a direct in-cylinder two-stroke engine for directly injecting fuel into a cylinder has been studied in order to gradually reduce the amount of unburned fuel, that is, hydrocarbon (HC). ing. In this direct in-cylinder injection two-cycle engine, fuel is supplied into the cylinder, and lubricating oil is not mixed with the fuel.
It is independently supplied to the crank chamber by an oil pump. For this reason, even if a large amount of lubricating oil is mixed with the fuel as in the prior art during a running-in period or the like, the lubricating oil mixed with the fuel is supplied to the cylinder but is not supplied to the crank chamber. Therefore, in the direct in-cylinder injection two-cycle engine, it is necessary to increase the discharge amount of the oil pump and supply a relatively large amount of lubricating oil into the crank chamber during a running-in period or the like. And, in particular,
When a mechanical pump was used as the oil pump, it was difficult to increase the amount.

An object of the present invention is to provide a two-stroke engine capable of relatively easily increasing the discharge amount of an oil pump during a break-in operation or the like. Aim.

[0005]

A two-stroke engine (9) of the present invention supplies a lubricating oil to a crank chamber (36) and changes a discharge amount of the lubricating oil. (52) Oil pump provided with)
A pump lever (96, 116) interlocked with the throttle valve (33a) and rotatably provided with respect to the discharge amount changing rotation shaft; and the pump lever and the discharge amount change rotation Switch the relative rotation position with the shaft, and
And a switching mechanism for fixing at the switched relative rotation position.

In addition, the switching mechanism is provided with an increasing locking portion (9).
3) a stationary locking portion (92) and an engaging portion (97) that selectively engages with one of the two locking portions. In some cases, a locking portion for increasing the volume and a locking portion for steady state are provided on one side, and a locking portion is provided on the other of the pump lever and the rotation shaft for changing the discharge amount.

[0007] Further, the switching mechanism is provided with a locking hole (11) for increasing the amount.
4) connecting hole (118), urging means (121) for rotating the discharge amount changing rotary shaft with respect to the pump lever, and increasing the number of connecting holes against the urging force of this urging means. It is constituted by a connecting pin (123) connected to the locking hole, and the discharge amount changing rotary shaft may be provided with an increasing locking hole and the pump lever may be provided with a connecting hole.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a first embodiment of a two-stroke engine according to the present invention will be described with reference to FIGS. FIG. 1 is a side view of an outboard motor equipped with a two-stroke engine according to the present invention. FIG. 2 is a plan sectional view of the two-stroke engine. FIG. 3 is a side view of the two-stroke engine. FIG. 4 is a sectional view of the oil pump, and FIG.
FIG. 4 is a sectional view taken along line IV-IV of FIG. FIG. 5 is a cross-sectional view of the oil pump, and is a VV cross-sectional view of FIG. FIG. 6 is a graph showing the relationship between the pump lever and the oil discharge amount. FIGS. 7A and 7B are explanatory views of the oil pump. FIG. 7A is a front view of the oil pump in a steady state, FIG. 7B is a front view of a rotating shaft lever, and FIG. 7C is a front view of a pump lever. 8A and 8B are explanatory views of the oil pump, in which FIG. 8A is a partially cutaway plan view, and FIG. 8B is a front view of the oil pump when the amount is increased. In this specification, the cylinder arrangement side is the rear side and the starboard side is the right side with respect to the crankshaft. Also, in FIG. 2, the left and right cylinders 11 are shown in communication, but are actually displaced in the vertical direction and are not in communication.

In FIG. 1, the outboard motor is covered by a housing consisting of an upper cowling 1, a lower cowling 2, an upper casing 3 and a lower casing 4 in order from the upper side. A mounting bracket 6 for mounting the outboard motor to a small boat is mounted and fixed to a transom 7 of the small boat. An outboard motor main body is rotatably attached to a rear portion of the mounting bracket 6 via a pivot shaft or the like.

Inside the cowlings 1 and 2 including the upper cowling 1 and the lower cowling 2, a two-cycle engine 9 of a direct in-cylinder injection V-type six cylinder is arranged. The rotation of the crankshaft 10 of the engine 9 is transmitted to a propeller 12 rotatably provided at a rear end of the lower casing 4 via a drive shaft, a bevel gear, a propeller shaft, and the like.

The crankshaft 10 of the engine 9 has a substantially vertical axis, and a pair of left and right cylinders 11 are arranged behind the crankshaft 10 in a V-shape in the left-right direction. I have. The pair of left and right cylinders 11 is provided in three stages in the vertical direction, and the cylinders 11 are arranged in a total of six cylinders. Also, six pistons 13 are connected to the connecting rods 14 on the crankshaft 10.
The piston 13 is slidably disposed inside each cylinder 11. The case 17 of the engine 9 includes a cylinder block 20 forming the above-described six cylinders 11 and a cylinder block 20.
Crankcase 21 that covers the side of the crankshaft 10
And a pair of left and right cylinder heads 22 that cover and close the combustion chamber 11a side of the cylinder block 20.

The cylinder head 22 is provided with a solenoid openable / closable injector 23 and a spark plug 24. The fuel pump sucks fuel such as gasoline from the fuel tank, pressurizes the fuel, and supplies the fuel to the injector 23 via the fuel rail 25 or the like. Each cylinder 11 is provided with three scavenging ports 26 and one exhaust port 27, and the piston 13 is moved from the bottom dead center position (that is, the dead center closer to the crankshaft 10) to the top dead center position. When it moves, the scavenging port 26 and then the exhaust port 27 are closed in this order. Conversely, piston 1
When 3 moves from the top dead center position to the bottom dead center position, the air outlet 27 and then the scavenging port 26 are opened in this order.

At the front of the crankcase 21, an air inlet 31 is formed so as to bulge forward.
The throttle body 33 is connected to the front of the throttle body 33, and a silencer 34 is connected to the front of the throttle body 33. The throttle body 33 has a throttle valve 3
3a, and a valve shaft 33b of the throttle valve 33a.
Are connected to and linked to a throttle lever (not shown) via a throttle wire (not shown) or the like.
Then, operate the throttle lever to set the throttle valve 3
By changing the opening of the throttle body 3a, the throttle body 3
3 is adjusted.

Cylinder block 20 and crankcase 2
The crank chamber 36, which is covered with the first and second crank chambers 3, is divided vertically into a number of cylinders, that is, six.
7 are formed. Similarly, the air introduction part 31 is also vertically divided into the number of cylinders, and six air flow paths 32 are formed. The air flow paths 32 communicate with the small crank chamber 37 corresponding to the same cylinder. Are isolated from the crank chamber 37 corresponding to the other cylinders. And the air channel 3
2 is provided with a reed valve 40 for backflow prevention. Each of the small crank chambers 37 communicates with the scavenging port 26 of the corresponding cylinder 11 through a scavenging passage 38. Each exhaust port 27 of the left cylinder 11 joins the left collective exhaust passage 41, while each exhaust port 27 of the right cylinder 11 joins the right collective exhaust passage 42. The combustion gas in the cylinder 11 is discharged from the exhaust port 27 to the outside of the outboard motor from the boss of the propeller 12 via a muffler, etc., through a left collective exhaust passage 41 and a right collective exhaust passage 42.

An oil pump 52 such as a mechanical pump is connected to the lubricating oil tank 51. The oil pump 52 has six discharge ports 53, which are the number of cylinders. The details of the oil pump 52 will be described later.
On the other hand, on the left side wall 31a of the air introduction section 31, a discharge pipe 54 is provided at an upper portion for each air flow path 32 from the outside to the inside by about 1 mm.
The end of the discharge pipe 54 extends right behind the reed valve 40. The outer end of the discharge pipe 54 is connected to a discharge port 53 of the oil pump 52.
Is connected to a supply hose 56. Then, when the oil pump 52 operates, the lubricating oil in the lubricating oil tank 51 is injected from the discharge pipe 54 into the air flow path 32 via the supply hose 56.

Further, a drain inlet 61 serving as an inlet of a lubricating oil return passage is provided in the scavenging passage 38 on the lower side of each cylinder 11.
(See FIG. 3). On the other hand, the six drain return ports 63 are formed above the right side wall 31b of the air introduction section 31 in the odd-numbered air flow paths 32 from the upper side,
Further, in the even-numbered air flow path 32 from the upper side, the air flow path 32 is formed above the left side wall 31 a of the air introduction part 31.
Each drain return port 63 is connected to a drain inlet 61 corresponding to another cylinder 11 by a return hose 64 as a lubricating oil return flow path via a check valve (not shown). The lubricating oil retained in the scavenging passage 38 is returned to the crank chamber 36 by the return hose 64.

The oil pump 52 is a well-known mechanical plunger pump, and includes a differential plunger 71, a drive shaft 72 for driving the differential plunger 71 to rotate, a sub-plunger 73, and a discharge amount changing rotary shaft. The cam rotation shaft 74 is provided. The oil pump 52 will be briefly described. The drive shaft 72 rotates in conjunction with the crankshaft 10 and has a worm gear 76 formed therein. The differential plunger 71 has a gear 75 engaged with the worm gear 76 of the drive shaft 72.
When the worm gear 76 rotates, the differential plunger 71 also rotates. Also, at one end of the differential plunger 71,
Three protrusions 77 are formed, and the protrusions 77 slide on large and small cams 78 and 79 of the cam rotation shaft 74. The large and small cams 78 and 79 are eccentric with respect to the cam rotation shaft 74, and the eccentricity of the small diameter cam 78 is larger than the eccentricity of the large diameter cam 79.

A spring 81 urges the differential plunger 71 toward the cam rotation shaft 74.
When the differential plunger 71 rotates, the protruding portion 77 slides along the large and small cams 78, 79, and reciprocates in the left-right direction in FIGS. With the reciprocation of the protrusion 77, the differential plunger 71 reciprocates in the axial direction. The inside of the differential plunger 71 is hollow, and the sub-plunger 73 is inserted into this internal space. When the drive shaft 72 rotates, the oil pump 52 configured as described above sucks the lubricating oil in the lubricating oil tank 51 from the lubricating oil suction port 84. The sucked lubricating oil passes through the flow path 86 of the main body of the oil pump 52 and is distributed through the flow path of the rotating and reciprocating differential plunger 71, and the six distribution flow paths 8 of the main body of the oil pump 52 are provided.
7 and is discharged from the six discharge ports 53 of the oil pump 52. The discharge amount of the oil pump 52 can be changed by rotating the cam rotation shaft 74. That is, when the cam rotation shaft 74 is rotated, the position of the small-diameter cam 78 having a large amount of eccentricity is changed to be larger than the position of the large-diameter cam 79, and the movement of the protrusion 77 in FIG. Since the left end is defined by the large-diameter cam 79 at the left end and the small-diameter cam 78 at the right end, the amount of reciprocating movement of the protrusion 77 in the left-right direction, that is, the reciprocating movement distance of the differential plunger 71 is changed. The discharge amount of the pump 52 is changed.

A rotary shaft side lever 91 is fixed to the cam rotary shaft 74 of the oil pump 52. The rotating shaft side lever 91 has a disk shape, and is formed with a stationary notch 92 as a stationary locking portion and an increasing notch 93 as an increasing locking portion. In this way,
A notch 92 for steady state and a notch 93 for increasing amount are provided indirectly fixed to the cam rotation shaft 74. A pump lever 96 is rotatably attached to the cam rotation shaft 74. The pump lever 96 is provided with an engagement projection 97 as an engagement portion, and a return spring 9.
At 8, it is constantly urged toward the rotating shaft side lever 91 side. The engagement protrusion 97 selectively engages with either the notch 92 for steady state or the notch 93 for increasing the amount of the cam rotation shaft 74. Further, an operation knob 99 is screwed and attached to the pump lever 96. By operating the operation knob 99, the engagement projection 97 of the pump lever 96 is moved to the notch 92 for steady state or the notch 9 for increasing the amount of the rotation shaft side lever 91.
By switching from one to the other and engaging it,
The relative rotation position between the pump lever 96 and the cam rotation shaft 74 is switched, and the switched relative rotation position is fixed. In this manner, a switching mechanism that switches the relative rotation position between the pump lever 96 and the cam rotation shaft 74 is constituted by the engagement protrusion 97, the notch 92 for steady state, the notch 93 for increasing the amount, and the like.

One end of the pump lever 96 is connected to an output lever 33c of a valve shaft 33b of the throttle body 33 via a link 101 which is an interlocking mechanism, and the pump lever 96 is connected to the valve shaft 33b of the throttle body 33. It rotates in conjunction with the rotation.

When the engine 9 configured as described above is operated, the air in the cowlings 1 and 2 is sucked in from the silencer 34, and the flow rate of the air is adjusted by the throttle body 33. It flows into the air flow path 32 of the air introduction part 31. In the air passage 32, the lubricating oil is discharged from the discharge pipe 54 and the drain return port 63, and flows into the small crank chamber 37 of the crank chamber 36 along with the flow of air. The air in the crank chamber 36, that is, the air in the small crank chamber 37 flows into the combustion chamber 11 a of the cylinder 11 through the scavenging passage 38. Fuel is appropriately discharged from the injector 23 into the combustion chamber 11a, and is ignited by the spark plug 24 and burned. The combustion gas, that is, the exhaust gas, passes through the left collective exhaust passage 41 and the right collective exhaust passage 42 and is exhausted to the outside of the outboard motor as described above.

When a throttle lever (not shown) is operated, the valve shaft 33b of the throttle body 33 rotates to change (increase) the opening of the throttle valve 33a, and the output lever 33 of the throttle body 33.
c and the link 101, the pump lever 96
Rotates. In a steady state, for example, after completion of the running-in operation, the pump lever 96
The cam rotation shaft 74 of the oil pump 52 through the engagement projection 97 of the oil pump 52 and the stationary notch 92 of the rotation shaft side lever 91.
And the cam rotation shaft 74 rotates with the rotation of the pump lever 96. Then, as shown by the solid line in FIG. 6, as the rotation of the pump lever 96 increases (that is, as the opening of the throttle valve 33a increases), the oil discharge amount of the oil pump 52 increases.

By the way, immediately after shipping the outboard motor,
It is necessary to perform a break-in operation. At this time, the oil discharge amount of the oil pump 52 is increased. That is, the operation knob 99 is pulled against the urging force of the return spring 98 to disengage the engagement projection 97 of the pump lever 96 from the stationary notch 92 of the rotation shaft side lever 91, and ,
By turning the operation knob 99, the engagement protrusion 97 of the pump lever 96 is engaged with the notch 93 for increasing the amount of the rotation shaft side lever 91. Then, the oil discharge amount of the oil pump 52 becomes the state shown by the broken line in FIG. 6, and is larger than the steady state shown by the solid line. Then, after the running-in period is over, the operating knob 99 is operated to engage the engaging projection 97 of the pump lever 96 with the stationary notch 92 of the rotating shaft side lever 91.

Next, a second embodiment of the two-stroke engine according to the present invention will be described with reference to FIGS. 9A and 9B are explanatory views of an oil pump according to a second embodiment, in which FIG. 9A is a front view of the oil pump in a steady state, FIG. 9B is a front view of a rotating shaft lever, and FIG. FIG. FIG. 10 is a partially cutaway plan view of the oil pump according to the second embodiment. 11A and 11B are explanatory views of an oil pump according to a second embodiment, in which FIG. 11A is a front view of the oil pump when the amount is increased, and FIG. 11B is a cross-sectional view near a connecting pin. In the description of the second embodiment, the same reference numerals are given to components corresponding to the components of the first embodiment, and a detailed description thereof will be omitted.

As described above, in the first embodiment, the switching mechanism of the oil pump 52 for switching the relative rotation position between the pump lever 96 and the cam rotation shaft 74 includes the engagement projection 97 and the stationary cut-off. Although it is composed of a notch 92 and a notch 93 for increasing the amount, in the second embodiment, the structure of this switching mechanism is different. That is, in the second embodiment, the rotation shaft side lever 111 fixed to the cam rotation shaft 74 is provided with the spring locking projection 112 as the first spring locking portion, and the rotation shaft side lever 111. A stopper 113 for restricting the rotation and a locking hole 114 for increasing the amount are formed. In this way, the stopper 113 and the locking hole 114 for the increasing amount are fixedly provided on the cam rotation shaft 74. I have. The pump lever 116 has a spring locking hole 117 as a second spring locking portion and a connection hole 118. Then, a coil spring 121 as an urging means is provided.
One end has a spring engaging protrusion 112 of the rotation shaft side lever 111.
The other end is engaged with the spring locking hole 117 of the pump lever 116, and urges the rotating shaft side lever 111, that is, the cam rotating shaft 74 in the counterclockwise direction in FIG. 9A.
By the urging force of the coil spring 121, the stopper 113 of the rotating shaft side lever 111
6 has been rotated in the direction of engagement.

The oil pump 52 constructed as described above
At the time of shipment, the connecting pin 123 constituted by a bolt or the like is connected to the locking hole 114 for increasing the amount of the rotation shaft side lever 111 and the connecting hole 1 for the pump lever 116.
18, the increasing locking hole 114 and the connecting hole 118 are connected to face each other. Then, after the running-in period ends, the connecting pin 123 is pulled out. Then, the coil spring 12
With the urging force of 1, the rotating shaft side lever 111, that is, the cam rotating shaft 74 rotates with respect to the pump lever 116, and the stopper 113 of the rotating shaft side lever 111 moves the pump lever 116.
Engages. Thus, the relative rotation position between the cam rotation shaft 74 and the pump lever 116 has been changed from the position in the increased amount state to the position in the steady state. Other operations are substantially the same as those of the first embodiment.

The embodiment of the present invention has been described above in detail.
The present invention is not limited to the above embodiment,
Within the gist of the present invention described in the claims,
Various changes can be made. Modification examples of the present invention are exemplified below. (1) In the above embodiment, the two-stroke engine is used in an outboard motor, but can be used in other devices including a two-stroke engine such as an automobile, a snowmobile, and a generator. Further, in the above-described embodiment, the two-cycle engine 9 is a V-type six-cylinder.
It can be changed as appropriate. For example, a single cylinder is also possible. Further, the two-cycle engine does not necessarily have to be a direct in-cylinder injection type.

(2) The positional relationship between the left and right members can be reversed. (3) In the above-described embodiment, the supply port for supplying the lubricating oil to the crank chamber 36 is constituted by the discharge pipe 54, but is not necessarily formed in a pipe shape. It is also possible to form it directly on 31b. Also, the arrangement of the supply ports can be changed as appropriate.

(4) In the first embodiment, the engagement projection 97 is provided on the pump lever 96, while the notch 92 for steady operation and the notch 93 for increasing the amount are provided on the rotation shaft side lever 9.
1, but it is also possible to provide the reverse.
In addition, the notches 92 and 93 as the locking portions can have other configurations as long as the engagement projections 97 as the engagement portions can be locked, and can be configured with holes, for example. is there. Furthermore, the engaging portion is formed by an opening such as a notch,
It is also possible to configure the two locking portions with protrusions that engage with this opening.

(5) The increased amount state can be used during periods other than the running-in period. (6) As long as the structure of the oil pump includes a discharge amount changing rotation shaft (cam rotation shaft 74) and a pump lever, other structures can be changed as appropriate. In addition, the discharge amount changing rotary shaft may have a structure other than the cam. (7) The notch 92 for normal operation, the notch 93 for increasing the amount, the stopper 113, the locking hole 114 for increasing the amount, and the like are indirectly provided on the cam rotation shaft 74 by the rotation shaft side levers 91 and 111. However, it is also possible to directly provide the cam rotation shaft 74. These stationary notches 92 and increasing notches 9
3. The stopper 113, the locking hole 114 for increasing the amount, and the like are provided so as not to be relatively movable with respect to the cam rotation shaft 74.

[0031]

According to the present invention, the switching mechanism switches the relative rotation position between the pump lever and the rotation shaft for changing the discharge amount of the oil pump, and fixes at the switched relative rotation position. I have. Therefore, by changing the relative rotation position between the pump lever and the discharge amount changing rotary shaft with this switching mechanism, the discharge amount of the lubricating oil can be reduced as compared with the time of steady operation, such as during the running-in period. Can be increased.
As described above, since the switching mechanism for switching the relative rotation position between the pump lever and the rotation shaft for changing the discharge amount of the oil pump is provided, not only the electric control type oil pump but also the mechanical type oil pump is provided. Can also be easily adopted.

In the case where the switching mechanism is constituted by a locking part for increasing the amount, a locking part for the normal state, and an engaging part which selectively engages with one of the two locking parts, By engaging the portion with the locking portion for increasing or the locking portion for steady state, the discharge amount of the lubricating oil of the oil pump can be easily changed.

Further, the switching mechanism includes a biasing means for rotating the increasing amount locking hole, the connecting hole, and the discharge amount changing rotation shaft with respect to the pump lever, and a biasing force against the biasing force of the biasing means. In some cases, the connecting hole is configured to connect the connecting hole to the locking hole for increasing the amount, and the locking hole for increasing the amount is provided on the rotation shaft for changing the discharge amount, and the connecting hole may be provided on the pump lever. . In such a case, simply by pulling out the connection pin, the urging force of the urging means causes the discharge amount changing rotary shaft to rotate with respect to the pump lever, thereby changing the discharge amount of the lubricating oil of the oil pump. You. Therefore, the discharge amount of the oil pump can be changed very easily.

[Brief description of the drawings]

FIG. 1 is a side view of an outboard motor equipped with a two-stroke engine according to the present invention.

FIG. 2 is a plan sectional view of a two-stroke engine.

FIG. 3 is a side view of the two-stroke engine.

FIG. 4 is a sectional view of the oil pump, taken along the line IV-IV in FIG.
It is sectional drawing.

FIG. 5 is a sectional view of the oil pump, and is a sectional view taken along line VV of FIG. 4;

FIG. 6 is a graph showing a relationship between a pump lever and an oil discharge amount.

FIGS. 7A and 7B are explanatory views of the oil pump. FIG. 7A is a front view of the oil pump in a steady state, FIG. 7B is a front view of a rotating shaft lever, and FIG. 7C is a front view of a pump lever. .

FIGS. 8A and 8B are explanatory views of the oil pump, wherein FIG. 8A is a partially cutaway plan view, and FIG. 8B is a front view of the oil pump when the amount is increased.

FIG. 9 is an explanatory view of an oil pump according to a second embodiment, in which (a) is a front view of the oil pump in a steady state,
(B) is a front view of the rotating shaft lever, and (c) is a front view of the pump lever.

FIG. 10 is a partially cutaway plan view of an oil pump according to a second embodiment.

FIGS. 11A and 11B are explanatory views of an oil pump according to a second embodiment, in which FIG. 11A is a front view of the oil pump when the amount is increased, and FIG. 11B is a cross-sectional view near a connecting pin.

[Explanation of symbols]

 9 Engine 33a Throttle valve 36 Crank chamber 52 Oil pump 74 Cam rotation axis (rotation axis for changing discharge amount) 92 Notch for steady state (locking part for steady state) 93 Notch for increasing amount (locking part for increasing amount) 96 Pump lever 97 Engagement projection (engagement part) 114 Enhancement locking hole 116 Pump lever 118 Connection hole 121 Coil spring (biasing means) 123 Connection pin

Claims (3)

[Claims] An oil pump that supplies a lubricating oil to a crank chamber and has a discharge amount changing rotary shaft for changing a discharge amount of the lubricating oil; A pump lever provided rotatably with respect to the rotary shaft for use, and a relative rotary position between the pump lever and the rotary shaft for changing the discharge amount, and fixed at the switched relative rotary position. A two-stroke engine, comprising: 2. The switching mechanism according to claim 1, wherein the switching mechanism includes a locking portion for increasing the amount, a locking portion for normal operation, and an engaging portion that selectively engages with one of the locking portions. It is characterized in that one of the rotation shafts for changing the amount is provided with a locking portion for increasing the amount and a locking portion for the steady state, and a locking portion is provided on the other of the pump lever or the rotation shaft for changing the discharge amount. The two-stroke engine according to claim 1, wherein 3. The urging means for rotating the increasing amount locking hole, the connecting hole, and the discharge amount changing rotary shaft with respect to the pump lever, and a biasing force against the urging force of the urging means. And a connecting pin connecting the connecting hole to the locking hole for increasing the amount. The locking hole for increasing the amount is provided on the rotation shaft for changing the discharge amount, and the connecting hole is provided on the pump lever. The two-stroke engine according to claim 1, characterized in that: