JPH0718328B2 - Oil pump device for internal combustion engine - Google Patents

Abstract

PURPOSE:To dispense with the oil pump heretofore in use by forming space between an eccentric driving cam being driven by a crankshaft and an eccentric inverted cam being driven by this driving cam at a 1/2 reduction gear ratio and having a tappet valve cam on the circumference as an oil pump house. CONSTITUTION:An eccentric driving cam Ca1 is engaged with a shaft part 21 of a crankshaft 2 through a spline and tightly attached to a nut 5 via a washer 4. An eccentric inverted cam Ca2 is circumscribed on the circumference of this eccentric driving cam Ca1 and it is made so as to be driven at a 1/2 reduction gear ratio. A tappet valve cam 6 is formed on the circumference of the eccentric inverted cam Ca2, and slipper surfaces 71 and 81 of cam followers 7 and 8 for suction and exhaust valves come into contact with this cam 6. A pump house 15 is formed in space between the eccentric driving cam Ca1 and the eccentric inverted cam Ca2, whereby intake oil from a suction port 16 is discharged out of discharge port 17, thus action as an oil pump is effectuated.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Field of Industrial Application The present invention comprises an eccentric drive cam and an eccentric driven cam that are provided on a crankshaft and are interposed in a valve train. / 2 The present invention relates to an oil pump device for an internal combustion engine configured using a speed reducer.

(2) Conventional Technology A trochoid pump, a gear pump, a plunger pump, or a vane pump is used as an oil pump for supplying lubricating oil to each lubricated portion of a conventional internal combustion engine (Automotive Engineering Complete Book 4, “Gasoline Engine”, Sankaido). reference).

(3) Problems to be Solved by the Invention However, both the conventional oil pump itself is expensive and
Since the pump is driven by a crankshaft via a transmission device such as a gear transmission mechanism, this not only causes the engine to be large and increase in weight, but also significantly increases the cost of the lubricating system of the engine. There is a problem.

The present invention has been made in consideration of the above circumstances, and is intended to reduce the rotation of the crankshaft by half and transmit it to the valve operating cam.
/ 2 It is an object of the present invention to provide an oil pump device for a new internal combustion engine in which the speed reducer can also be used as the lubricating oil pump.

B. Structure of the Invention (1) Means for Solving Problems According to the present invention for achieving the above object, according to the present invention, an eccentric drive cam driven by the crankshaft is rotatably supported by the engine body. Is circumscribed on the outer peripheral surface of the cam and rotatably supported by the engine body, and is 1 /
(2) Provide a 1/2 speed reducer consisting of an eccentric driven cam driven at a reduction ratio, and form a valve cam on the outer peripheral surface of the eccentric driven cam.
An intake / exhaust cam follower of a valve mechanism is connected to the valve cam, and a variable volume space defined between the eccentric drive cam and the eccentric driven cam is oil-tightly sealed to form a pump chamber,
The pump chamber communicates with an intake port and a discharge port that are opened and closed by rotation of the eccentric drive cam and the eccentric driven cam, the suction port communicates with an oil reservoir, and the discharge port communicates with an oil supply passage.

(2) Operation According to the above configuration, the rotation of the crankshaft actuates the 1/2 speed reducer, the valve cam on the outer periphery of the 1/2 speed reducer is rotated, and the intake / exhaust valve is set to a predetermined position via the valve actuation mechanism including the cam follower. It is opened and closed at the timing. Further, an oil pump is constituted by the eccentric drive cam and the eccentric driven cam of the 1/2 speed reducer,
The pump can forcibly supply the oil in the oil reservoir to the lubricated portion of the engine.

(3) Embodiment An embodiment in which the device of the present invention is applied to a vertical crankshaft type four-cycle internal combustion engine will be described below with reference to the drawings.

1 to 3, the crankcase 1 of the engine body E is rotatably supported by a crankshaft 2 arranged in the vertical direction. The bottom wall 1 ₁ of the crank case 1, the reduction gear chamber 3 is formed to surround the shaft portion 2 ₁ of the crankshaft 2, the chamber 3
A 1/2 speed reducer R, which will be described later, is accommodated therein and is interlocked with the crankshaft 2. The 1/2 reduction gear R shaft portion 2 ₁ of the crankshaft 2
The eccentric drive cam Ca ₁ which is fixed by a nut 5 spline engaged via a washer 4, a is circumscribing the outer periphery of the cam Ca _1, it is rotatably supported by the bottom wall 1 ₁ of the crankcase 1 It is composed of an eccentric driven cam Ca _2, and as described later, the rotation of the crankshaft 2, that is, the eccentric drive cam Ca ₁ is decelerated by 1/2 and transmitted to the eccentric driven cam Ca ₂ . One valve cam 6 is integrally formed on the outer circumference of the eccentric driven cam Ca ₂ , and the cam surfaces of the valve cam 6 are connected to the cam followers 7 and 8 of a conventionally known valve gear.
Therefore, the rotation of the crankshaft 2 is reduced by 1/2 through the 1/2 speed reducer R and transmitted to the valve operating cam 6, and the rotation of the valve operating cam 6 normally causes the cam followers 7 and 8 to move. An intake / exhaust valve provided in the combustion chamber can be opened / closed at a predetermined timing via a valve device.

Next, the configuration of the 1/2 speed reducer R will be described in more detail.
The eccentric drive cam Ca ₁ fixed so as to rotate integrally with the crankshaft 2 has a pair of first and second eccentric wheels 10 ₁ , 10 _2.
Are installed side by side. The pair of first and second eccentric wheels 10
_The eccentric driven cam Ca ₂ circumscribing ₁ and 10 ₂ is the first and second eccentric wheels 10 ₁ and
Eccentricity e equal to the eccentricity e of 10 ₂ with respect to the crankshaft 2
In which it is rotatably supported by the bottom wall 1 ₁ of the crankcase 1. _On the outer peripheral surface of the eccentric driven cam Ca ₂ , one valve operating cam 6 for intake and exhaust is formed.
The slipper surfaces 7 ₁ , 8 _{1 of the} exhaust cam followers 7, 8 are in contact with each other.

The first and second eccentric wheels 10 ₁ and 10 ₂ have a cylindrical outer peripheral surface having a circular cross section, and are eccentric from the central axis C ₀ of the crankshaft 2 in opposite directions when viewed in the diametrical direction of the crankshaft 2. Only eccentric.

A hollow portion of the eccentric driven cam Ca ₂ having a central axis C ₁ eccentric from the central axis C ₀ of the crankshaft 2 by an eccentric amount e is formed corresponding to the positions of the first and second eccentric wheels 10 ₁ and 10 _2. The first and second inner peripheral surfaces 12 ₁ and 12 ₂ surround the outer peripheral surfaces of the first and second eccentric wheels 10 ₁ and 10 ₂ .

The first inner peripheral surface 12 ₁ is a pair of parallel facing surface portions 12 that are parallel to each other and rotate while circumscribing the first eccentric wheel 10 ₁ while the first eccentric wheel 10 ₁ is sandwiched between the first inner peripheral surface 12 ₁ and the crankshaft 2. ₁ -1,12 ₁ -2
In addition, the second inner peripheral surface 12 ₂ always has the second eccentric ring 10 ₂ sandwiched between the second inner peripheral surface 12 ₂ as the crankshaft 2 rotates.
The eccentric ring 10 ₂ has a pair of opposing surface portions 12 ₂ -1,12 ₂ -2 that are parallel to each other and rotate while being circumscribed, and each opposing surface portion of the first inner peripheral surface 12 ₁
12 ₁ -1,12 ₁ -2 and each of the opposing surface portions of the second inner peripheral surface 12 ₂ 12 ₂ -1,12 ₂ -2
And are formed so that their phases are shifted from each other by 90 °.

The 1/2 speed reducer R is also configured as an oil pump P for supplying lubricating oil to each lubricated portion of the engine. One side surface of the first eccentric wheel 10 ₁ of the eccentric drive cam Ca ₁ is slidably and liquid-tightly in contact with the wall surface of the crankcase ₁ , and the other end surface of the first eccentric wheel 10 ₁ has an eccentric driven cam. The flange-shaped picture wall 14 formed integrally with the inner peripheral surface of Ca ₂ is slidably and liquid-tightly attached to the outer peripheral surface of the first eccentric ring 10 ₁ and the hollow portion of the eccentric driven cam Ca ₂ . A space between the first inner peripheral surfaces 12 ₁ is formed in a crescent-shaped pump chamber 15 when viewed from the side, and the pump chamber 15 has a variable capacity due to relative rotation between an eccentric drive cam Ca ₁ and an eccentric driven cam Ca ₂ as described later. And the pumping action takes place.
A circular suction port 16 of the pump chamber 15 is opened in the drawing wall 14, and the suction port 16 communicates with an oil reservoir 20 formed in the speed reducer chamber 3. And the first eccentric wheel 10 ₁
Also, according to the rotation of the eccentric driven cam Ca ₂ , the pump chamber 15 is communicated with or cut off from the communication. Also in the bottom wall 1 ₁ of the crank case 1 the pump chamber 15
The discharge port 17 is formed adjacent to
Is the first eccentric wheel 10 ₁ and the eccentric driven cam Ca _{2 as} will be described later.
Is connected to the pump chamber 15 or is cut off from the communication, and the discharge port 17 is provided with an oil supply passage 18 formed in the crankshaft 2 and a bottom wall of the crankcase 1.
1 ₁ is in fluid normally with the oil supply passage 19 formed in the oil pressurized by the oil pump P is pumped to respective lubricated parts of the engine through the oil supply passage 19 from the discharge port 17.

Oil reservoir 20 is formed to the bottom wall 1 ₁ of the crank case 1 surrounds the outer periphery of the 1/2 reduction gear R, the oil reservoir
20 through the notch 21 formed in the bearing of the eccentric driven cam Ca ₂
/ 2 It communicates with the reduction gear R, and the reduction gear R is immersed in oil.

In each of FIGS. 4 (a) to 6 (a), when the first eccentric wheel 10 ₁ is eccentric to the right, the facing surface portions 12 ₁ -1,12 ₁ -2
Extends in the horizontal direction, and at this time, the second eccentric wheel 10 ₂ is eccentric to the left and the facing surface portions 12 ₂ -1,12 ₂ -2 extend in the vertical direction. In this state, the crankshaft 2
Rotate in the direction of arrow f, each pair of facing surface parts
Of the pair of outer tangent lines to the second eccentric wheels 10 ₁ and 10 ₂ , on the outer tangent line on the side where the distance from the central axis C ₀ of the crankshaft 2 increases, the first and second eccentric wheels 10 ₁ and 10 _{1 2} presses the facing surface portion and transmits torque to the eccentric driven cam Ca ₂ . That is, the first eccentric wheel 10 ₁ presses the facing surface portion 12 ₁ -1 and
The eccentric wheel 10 ₂ presses the facing surface portion 12 ₂ -1. As a result, the first
When the rotation of the second eccentric wheels 10 ₁ and 10 ₂ advances by 90 °,
~ As shown in Fig. 6 (b), the rotation of the eccentric driven cam Ca ₂ is 45 °.
move on. The first eccentric wheel 10 ₁ continues to press the facing surface portion 12 ₁ -1, and the second eccentric wheel 10 ₂ continues to press the facing surface portion 12 ₂ -1,
When the rotation of the first and second eccentric wheels 10 ₁ and 10 ₂ advances by 180 °, the fourth to sixth
As shown in each figure (c), the rotation of the eccentric driven cam Ca ₂ advances by 90 °. When the first and second eccentric wheels 10 ₁ and 10 ₂ rotate further at this point, the first eccentric wheel 10 ₁ starts to push the facing surface portion 12 ₁ -2, and the second eccentric wheel 10 ₂ moves to the facing surface portion 12 _2-. Press and hold 1. First
When the rotation of the _first and second eccentric wheels 10 ₁ and 10 ₂ further advances to 270 °, the eccentric driven cam Ca ₂ as shown in each of FIGS. 4 to 6 (d).
Rotates by 135 °.

As described above, the rotation of the crankshaft 2 causes the eccentric drive cam Ca
₁ and the eccentric driven cam Ca ₂ are shown in FIGS. 4 to 6 (a) to (d).
The rotation of the crankshaft ₂ is transmitted to the eccentric driven cam Ca ₂ with a speed reduction ratio of 1/2 by repeating the rotary motion shown in Fig. ₃ , and the valve cam 6 on the eccentric driven cam Ca ₂ causes the pair of cam followers to move as described above. 7, 8 are swung, and intake and exhaust valves (not shown) are operated via the push rod.

By the way, while the 1/2 reduction gear R makes one rotation as described above, the oil pump P operates as follows to suck the oil in the oil sump 20 and feed it to the oil supply passages 18 and 19 under pressure. 4 to 6 each state (a), that is, the rotation angle of the crankshaft 2 is 0
The pump chamber 15 has the largest volume at 0 °, the suction port 16 having a large opening communicates with the pump chamber 15, and the oil in the oil reservoir 20 flows into the pump chamber 15 through the suction port 16.

When the rotation of the crankshaft 2 advances 90 °, the first eccentric wheel 10
_Since the rotation of ₁ also advances 90 °, as shown in each of FIGS. 4 to 6 (b), the volume in the pump chamber 15 begins to decrease, but the suction port 16 is still open, so that the pump action does not occur. .

When the crankshaft 2 rotates 180 °, the first eccentric wheel 1
0 As shown in the fourth to sixth Figure ₁ also rotates proceed 180 ° (c), together with the volume of the pump chamber 15 is reduced further, the suction port 16 is closed by the first eccentric ring 10 _1, whereas the discharge Since the port 17 communicates with the pump chamber 15,
The pressurized oil in 15 passes through the discharge port 17 and the oil supply passages 18, 19
The oil is supplied to the engine to lubricate the lubricated portion of the engine.

When rotated to 270 ° proceeding rotation of the crank shaft 2 and the first eccentric ring 10 ₁ Further, the pumping volume further reduced to the pump chamber 15 as in the fourth to sixth diagram each (d) is continued To be done.

If rotated to the rotation of the crank shaft 2 and the first eccentric ring 10 ₁ go further 360 °, they view the 4-6 each (a)
Then, one cycle of the pump action is completed, and the same pump action as described above is performed in the other pump chamber formed on the opposite side of the pump chamber 15 with the rotation of the crankshaft 2.

C. Effects of the Invention As described above, according to the present invention, since the 1/2 speed reducer installed in the valve train of the four-cycle internal combustion engine can be configured as an oil pump, the conventional oil pump described above can be used. It becomes unnecessary and the weight of the engine can be greatly reduced and the cost can be reduced.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, and FIG.
II is a sectional view taken along line II-II in FIG. 1, FIG. 3 is a sectional view taken along line III-III in FIG. 1, and FIG.
5 (a) to 5 (a) to 5 (a) to 5 (a) to 5 (a) to (d) sequentially show the relationship between the first eccentric cam and the eccentric driven cam corresponding to the change in the rotation angle of the crankshaft. FIG. 6 (d) is the same sectional view as FIG. 3 showing the relationship between the second eccentric cam and the eccentric driven cam sequentially corresponding to the change in the rotation angle of the crankshaft, and FIG.
It is the same sectional view as FIG. 1 shown corresponding to FIGS. 2 and 3 (a) to (d). Ca ₁ …… Eccentric drive cam, Ca ₂ …… Eccentric driven cam, E …… Engine body 2 …… Crankshaft, 7,8 …… Cam follower, 11 …… Valve cam, 15 …… Pump chamber, 16 …… Intake port, 17 …… Discharge port, 18,19 …… Oil supply path, 20 …… Oil sump

Claims (1)

[Claims] 1. An eccentric drive cam (Ca ₁ ) driven by the crank shaft (2) and a crank shaft (2) rotatably supported by an engine body (E) and the cam (Ca ₁ ). 1/2 reducer consisting of an eccentric driven cam (Ca ₂ ) circumscribed on the outer peripheral surface and rotatably supported by the engine body (E) and driven at a 1/2 reduction ratio by the eccentric drive cam (Ca ₁ ) Is provided, and a valve operating cam (6) is formed on the outer peripheral surface of the eccentric driven cam (Ca ₂ ). The intake and exhaust cam followers (7, 7) of the valve operating mechanism are formed on the valve operating cam (6).
8) is connected, and a variable volume space defined between the eccentric drive cam (Ca ₁ ) and the eccentric driven cam (Ca ₂ ) is oil-tightly sealed to form a pump chamber (15). The chamber (15) communicates with the suction port (16) and the discharge port (17) which are opened and closed by the rotation of the eccentric drive cam (Ca ₁ ) and the eccentric driven cam (Ca ₂ ), and the suction port (16) is connected to the chamber (15). Connect the discharge port (17) to the oil sump (20) and the oil supply passage (18,1).
An oil pump device for an internal combustion engine, which is characterized by communicating with 9) respectively.