JPH0811932B2 - Engine supply lubricating oil metering device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supply lubricant oil metering device for metering and pumping lubricant oil to an engine such as a rotary piston engine or a two-cycle engine.

(Prior Art) Conventionally, for supplying lubricating oil to a combustion chamber of a two-cycle engine or the like to lubricate a gas seal portion, a metering oil pump that changes the lubricating oil supplied to the engine according to an operating state is provided. Those known are known. (Actual development
Further, in the above metering oil pump, generally, a plunger that rotates in association with engine rotation is reciprocally provided, and the reciprocating stroke of the plunger causes the reciprocating stroke. The amount is adjusted by rotating the cam shaft with which one end of the plunger abuts, and the amount of lubricating oil supplied is changed. The cam shaft has a cam surface formed in a small size with respect to the base circle at a portion where one end of the plunger contacts, and the tip of the plunger contacts the base circle and the cam surface as the plunger rotates. The plunger reciprocates with a stroke corresponding to the difference in radius between the two, and the stroke amount is changed by changing the contact radius of the cam surface formed in an eccentric shape by the rotation of the cam shaft, and the amount of lubricating oil discharged Is adjusted.

(Problems to be Solved by the Invention) When moving the cam shaft for adjusting the stroke amount of the plunger as described above, the suction port and the discharge port formed in the pump housing may be changed depending on the rotation angle of the plunger. The plunger is forced to move via the cam shaft during the closed period when it is not in communication with any of the ports, and a large driving force due to liquid compression acts on the driving mechanism, and the control signal output to the driving mechanism and the actual movement. There is a problem that a step-out phenomenon occurs in which the correlation with the amount shifts, and it becomes difficult to secure the control accuracy of the discharge amount.

Therefore, in view of the above circumstances, the present invention provides a lubricating oil measuring device for an engine, which has a simple structure and avoids the occurrence of a step-out phenomenon in relation to the closing period of the plunger in the movement of the cam shaft. It is intended.

(Means for Solving the Problems) In the supply lubricating oil measuring device of the present invention, the cam surface of the cam shaft with which one end of the plunger contacts is formed in a surface shape in which the cross-sectional area decreases in one axial direction. At the same time, driving means for moving the cam shaft in the axial direction is provided, and the driving means moves the cam shaft in the direction in which the cross-sectional area of the cam surface decreases and in the direction in which the cross-sectional area of the cam surface increases. The step motor and the cam shaft are separated from each other.

(Operation) In the above device, in order to discharge a predetermined amount of lubricating oil by changing the stroke area of the plunger by changing the cross-sectional area of the cam surface with which the plunger contacts by moving the cam shaft, The cam shaft is moved by the driving of the step motor in the direction in which the cross-sectional area of the cam surface is decreased, while it is moved by the urging force of the urging means in the direction in which the cross-sectional area is increased. When the plunger moves in the direction in which the cross-sectional area increases during the closed period when the plunger is not in communication with both the suction port and the discharge port because it is not connected to the cam shaft, the step motor is operated during the closing period. Prevents the occurrence of liquid compression without moving the cam shaft away from the cam shaft,
The occurrence of step-out phenomenon is avoided in advance to ensure control accuracy and improve the reliability of this camshaft drive system.

(Examples) Examples of the present invention will be described below with reference to the drawings.

FIG. 5 shows a schematic configuration of a rotary piston engine equipped with a weighing device according to an embodiment of the present invention.

The casing 1 of the rotary piston engine is composed of a rotor housing 2 having a trochoidal inner peripheral surface 2a and side housings 3 arranged on both sides thereof. Further, the substantially triangular rotor 4 which makes a planetary rotational movement in the casing 1 is supported by an eccentric shaft 5, and the casing 1
Three working chambers 6 are formed in the interior of the rotor 4.
The intake stroke, compression stroke, explosion stroke, expansion stroke, and exhaust stroke are sequentially performed with the rotation of the. An apex seal 7 slidingly contacting the inner peripheral surface 2a of the rotor housing 2 is mounted on each top of the rotor 4, side seals 8 slidingly contacting the inner surface of the side housing 3 are mounted on both side surfaces of the rotor 4, and the rotor 4 Corner seals 9 are attached to both side ends of each of the above.

The casing 1 is provided with an intake port 10 that opens to the working chamber 6 in the intake stroke through the side housing 3, and an exhaust port 11 that opens to the working chamber 6 in the exhaust stroke through the rotor housing 2. An intake passage 12 and an exhaust passage 13 are connected to the intake port 10 and the exhaust port 11, respectively. A pair of spark plugs 14 are attached to the rotor housing 2 at predetermined positions, and the intake port 10
An injector 15 for injecting fuel is installed in the nearby intake passage 12.

Further, a port oil supply nozzle 16 is attached so as to face the intake passage 12, and from this port oil supply nozzle 16 to a port oil supply port.
Lubricating oil discharged through 16a is port-lubricated into the casing 1 through the intake passage 12, and a direct lubrication nozzle 17 is attached to face the inner peripheral surface 2a of the rotor housing 2, and the direct lubrication nozzle 17 directly The lubricating oil discharged through the oil supply port 17a is the casing 1
It is directly refueled inside. The port oiling nozzle 16 has a metering oil pump as a lubricating oil metering device.
The first lubricating oil supply passage 18 is connected from 20. The direct lubrication nozzle 17 is connected with the second lubricating oil supply passage 19 from the metering oil pump 20. In addition, the air passage 16 is provided in the port and the direct fueling nozzles 16 and 17.
b and 17b are connected.

The engine shown in the figure has two cylinders, and a port oil supply nozzle 16 for port oil supply and a direct oil supply nozzle 17 for direct oil supply are provided in cylinders not shown as well, and lubricating oil is separately supplied from the metering oil pump 20. The passages 18 and 19 are connected.

The metering oil pump 20 is designed to measure and discharge lubricating oil, and the discharge amount is controlled by the control unit 25 (ECU) with respect to the step motor 21 as the driving means.
A control signal is output from the control unit and controlled according to the operating condition. The control unit 25 includes an air flow meter 26 for detecting the amount of intake air, a rotation speed sensor 27 for detecting the engine speed, a water temperature sensor 28 for detecting the temperature of the cooling water (engine temperature), and an acceleration state of the engine. Acceleration switch
Each signal from 29 is input. Then, the metering oil pump 20 and the control unit 25 control the ratio of refueling from the refueling nozzles 16 and 17 depending on the operating state, as described later.

1 to 3 show the above metering oil pump 20.
It shows a specific structure of the pump housing 31,
A first plunger 32 that measures and discharges lubricating oil for port lubrication and a second plunger 33 that measures and discharges lubricating oil for direct lubrication are arranged in parallel and reciprocally movable. Both plungers 32, 33 are divided into a front part and a rear part, respectively, and the center holes of the rear parts are respectively pin 34, 3
It is inserted in 5 (fixed to the housing side).

Further, a cam shaft 36 is inserted into the pump housing 31 in a direction orthogonal to the plungers 32, 33, and the cam shaft 36 has first and second cam surfaces 36a, 36a, 36a, 36a, 36b, which contact the tip end portions of the plungers 32, 33. Has 36b. This first and second cam surface 3
Each of 6a and 36b is formed in a tapered surface shape whose cross-sectional area decreases and decreases in one axial direction.

The plungers 32, 33 are biased toward the cam shaft 36 by springs 37, 38 arranged on the outer circumferences of the pins 34, 35. Further, the plungers 32 and 33 are provided with the gear portion 32.
The a and 33a are engaged with a driving worm 39 that is interlocked with the output shaft of the engine and driven and rotated. Plunger 3
The tip ends of 2, 33 have both side ears 32b, 33b and central protrusions 32c, 33c, and the state in which the ears 32b, 32b ride on the base circle 36c of the cam shaft 36 and the central protrusions 32c, 33c. The cam faces 36a and 36b are displaced and moved back and forth. Due to the rotation and reciprocating movement of the plungers 32, 33, the pins 34, 33 inside the plungers 32, 33 are
35 In the metering chambers 32d and 33d where the volume in front of the 35 changes, suction of lubricating oil from each suction port 40 and discharge of lubricating oil to the discharge ports 41a to 41d are alternately repeated.

That is, the lubricating oil is introduced from the journal portion of the driving worm 39 to the outer peripheral portion of the cam shaft 36, and from here, the suction passage 42 formed in parallel with the plungers 32 and 33 opens on both sides orthogonal to the plungers 32 and 33. It communicates with the suction port 40. On the other hand, in the plungers 32 and 33, the suction ports 32e and 33e are opened at positions where they can communicate with the suction port 40, and the discharge ports 32f and 33f are axially displaced and opened, and the discharge ports 41a to 41a of the pump housing 31 are opened. 41d is the suction port
It opens on both sides orthogonal to 40. The two first discharge ports 41a, 41b corresponding to the first plunger 32 are provided with first lubricating oil supply passages 18, 18 for port oil supply to the first and second cylinders.
The second lubricating oil supply passages 19, 19 for direct oil supply to the first and second cylinders are connected to the two second discharge ports 41c, 41d corresponding to the second plunger 33.

The movement of the cam shaft 36 in the axial direction is performed by a driving means. As this drive means, the cam shaft 36
A stroke type step motor 21 that moves in the direction in which the cross-sectional areas of a and 36b decrease, and a biasing means 43 that returns the cam shaft 36 in the direction in which the cross-sectional areas of the cam surfaces 36a and 36b increase (return Spring).
The shaft 21a of the step motor 21 operates to move in and out in the axial direction and is arranged coaxially with the cam shaft 36, but is separated from the cam shaft 36, and the cam shaft 36 is attached by a return spring 43 as an urging means. It is urged and linked so that one end thereof comes into pressure contact with the shaft 21a. Therefore, the camshaft 36 is the first
It moves downward (increase direction) in the figure by the driving force of the step motor 21, and moves upward (decrease direction) by the urging force of the return spring 43. The step motor 21 receives the pulse signal output from the control unit 25, and
The cam shaft 36 is slid only by one step (constant length) by inputting a pulse.

In the above metering oil pump 20, the cam shaft 36
By changing the radius of each cam surface 36a, 36b due to sliding, the moving stroke of each plunger 32, 33 is changed, and the amount of lubricating oil discharged per unit rotational speed of the engine is changed. And
The discharge amount per unit rotational speed can be electrically controlled by the control unit 25 via the step motor 21.
Further, the characteristics of the change in the discharge amount can be individually set for the port lubrication and the direct lubrication by the shapes of the cam surfaces 36a, 36b.

Therefore, by differentiating the shapes of the cam surfaces 36a and 36b in advance, the discharge amount and the discharge ratio from the discharge ports 41a to 41d can be variously changed by the change of the axial position of the cam shaft 36, The discharge amount and the discharge ratio are controlled by controlling the motor 21 according to the operating state. For example, FIG. 4 shows the characteristic of the change of the discharge amount Q per unit rotation speed according to the step number N of the step motor 21. Port lubrication is indicated by the first cam face 36a as indicated by the broken line, and direct lubrication is indicated by the second cam face.
36b is set as shown by the solid line. That is, as the step number N of the step motor 21 increases from 0, the discharge amount of direct lubrication becomes the first step number.
The lower limit value Q ₁ is set up to N ₁ , and when the first step number N ₁ is exceeded, the ejection amount changes linearly as the step number N increases to the upper limit value Q _{2 of} the third step number N ₃ . on the other hand,
The discharge amount of port refueling is the lower limit value up to the second step number N _2.
Q ₁ is set so that when the number of second steps N ₂ is exceeded, the ejection amount linearly increases to the upper limit value Q _{2 of} the third number of steps N _{3 as} the number of steps N increases. The above-mentioned discharge characteristics are set so that direct refueling is more efficient but has an upper limit value, and the discharge non-rate changes so that the shortage of direct refueling is supplemented by port refueling.

Then, the control unit 25 obtains the basic discharge amount according to the intake air amount and the engine speed, corrects it according to the water temperature, acceleration, etc., and drives the step motor 21 corresponding to the final oil supply amount. The number of steps N is calculated and a predetermined pulse signal is output to the step motor 21 to control the supply of lubricating oil.

In the above embodiment, when increasing the discharge amount of the lubricating oil, the cam shaft 36 is moved downward in FIG.
The central protrusions 32c and 33c of the tip ends of the plungers 32 and 33 are brought into contact with the small radius portion of 36b, and the difference from the base circle 36c, that is, the stroke amount is increased to increase the amount.
On the other hand, when the discharge amount is reduced, a pulse is output in the direction of decreasing the step number N, and the step motor 21 is driven so as to move the cam shaft 36 upward in FIG.

At that time, the shaft 21a of the step motor 21 and the cam shaft are not connected, and the cam shaft 36 is moved by the return spring 43 in the weight reducing direction. Inlet 32e, 33e and outlet 32f, 33f of plunger 32, 33 are pump housing
Plunger 32, 33 when not in communication with either the suction port 40 or the discharge port 41a to 41d on the 31st side
Sliding in the direction of compression causes a large load on the step motor 21 to cause the step motor 21 to fail to operate, resulting in a step-out phenomenon in which the number of steps with respect to the pulse signal shifts, and the control accuracy deteriorates. By the separation of the shaft 21a of the step motor 21 and the cam shaft 36, the step-out phenomenon is prevented from occurring.

On the other hand, when the lubricating oil is discharged as described above, if the discharge ports 41a to 41d or the lubricating oil supply passages 18 and 19 are clogged and the lubricating oil is not fed, the boosted lubricating oil is used. Leaks from the outer periphery of the plungers 32, 33 to the split parts of the plungers, and the rear parts of the plungers 32, 33 are springs 37, 38.
Against the rotational movement of the worm 39 to prevent further pressure rise.

In addition, the use of the stroke type step motor 21 eliminates the need for a reduction mechanism in the drive system using a rotary step motor, and the drive system can be made compact, and the mounting accuracy of the step motor 21 can be easily managed. Become.

(Effect of the Invention) According to the present invention as described above, when the cam shaft is moved to change the stroke amount of the plunger and discharge the lubricating oil amount according to the operating state, the cross-sectional area of the cam shaft is reduced. The plunger is not in communication with both the suction port and the discharge port by setting the direction of change, the driving direction by the step motor of the driving means and the biasing direction by the biasing means, and separating the step motor and the cam shaft. In the closed period in the state, the plunger is separated from the cam shaft without moving the plunger in the compression direction by driving the step motor, and the step motor itself maintains the driving corresponding to the predetermined control signal to prevent the step-out phenomenon. It is possible to prevent the occurrence of the discharge, ensure good control accuracy, perform discharge control, and improve reliability.

[Brief description of drawings]

1 is a longitudinal sectional view of a metalling oil pump according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is a sectional view taken along line III-III thereof. FIG. 4 is a characteristic diagram showing the discharge characteristic of the metering oil pump, and FIG. 5 is an overall configuration diagram of a rotary piston engine equipped with a supply lubricating oil metering device. 16,17 …… Lubrication nozzle 18, 19 …… Lubrication oil supply passage 20 …… Metalling oil pump 21 …… Step motor, 25 …… Control unit 31 …… Pump housing 32, 33 …… Plunger 36 …… Cam shaft , 39 …… Worm 36a, 36b …… Cam surface 36c …… Basic circle, 40 …… Suction port 41a ～ 41d …… Discharge port 43 …… Return spring

Claims (1)

[Claims] Claim: What is claimed is: 1. A plunger that reciprocates in a pump housing to pump lubricating oil, and abutting one end of the plunger,
A supply lubricating oil metering device for an engine, comprising: a cam shaft that changes the reciprocating stroke of the plunger; and a lubricating oil metering device for adjusting the amount of lubricating oil that is supplied to the engine. And a driving means for axially moving the cam shaft, the driving means forming the cam shaft in the direction of decreasing the cross-sectional area of the cam surface. An engine supply lubricating oil metering, characterized in that it comprises a step motor for moving and a biasing means for moving in a direction in which the cross-sectional area of the cam surface increases, and the step motor and the cam shaft are separated. apparatus.