JPH0423113B2 - - Google Patents

Abstract

PURPOSE:To obtain an oil pump suitable for a two cycle engine, by providing two kinds of control mechanisms, which supply oil with delivery characteristics being different in response to the load of the engine, in one oil pump. CONSTITUTION:When a worm wheel 22 is rotated by a worm 21 which is associatively moved by the rotation of a two cycle engine, a projection 23 rides on a concentric cam 15 against the energizing force of a coil spring 30 at the time of a discharge stroke. At the time of intake stroke, when the projection 23 is inserted in the concentric cam 15 by the energizing force of the coil spring 30, the worm wheel 22 performs two reciprocating movements per rotation of the rotary movement. At the discharge sroke, a plunger 27 is moved rightward together with the worm wheel 22, a discharge path 38 of a first actuating chamber 31 is aligned with a discharge port 43a, a discharge path 40 of a second actuating chamber 32 is aligned with a discharge port 44b, and the discharge of the oil is completed. The actuating chamber 31 is operated along the entire operating region of the engine. The actuating chamber 32 performs the oil intake and discharge only when the load is equal to the preset load of the engine or more.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to an oil pump most suitable for an engine.

(Prior art) Conventionally, as a pump that controls the suction and discharge amount by introducing two types of control elements at the same time in one pump, there is a plunger pump shown in Fig. 1 disclosed in Japanese Patent Publication No. 53-25124. , a pump body 1 having a cylinder chamber 1a, an inlet port 1b, and at least one discharge port 1c, and end face cams 2a and 3a at each outer end, which rotate integrally in the direction of rotation and in the axial direction. A pair of plungers 2 and 3 are rotatably and slidably fitted in the cylinder chamber 1a while being connected to allow relative movement, and the main body 1 is rotatable by interlocking with each control element. The plungers 2 and 3 include a pair of guide cylindrical members 6 and 7 that are attached to the end face cams 2a and 3a, respectively, and are pressed so as to be separated from each other, and the plungers 2 and 3 are pressed so as to be spaced apart from each other. 1b and the discharge port 1c are formed, and suction and discharge are performed by rotationally driving one of the pair of plungers 2 and 3, and the amount of suction and discharge is varied by the control element. It was designed so that

(Problems to be Solved by the Invention) In general, the degree of lubrication required by an engine is high at high loads when the engine temperature is high, especially at high loads and high rotations, and low at low loads, and if more oil is supplied than necessary, When using the above-mentioned plunger pump as an oil pump for an automobile engine, there is a problem that not only increases oil consumption but also causes spark plugs to smolder. It is necessary to supply oil with different discharge characteristics, and there is also a demand for miniaturization because it needs to be installed in a narrow engine room. However, with the plunger pump described above, the discharge characteristics from the two discharge ports are the same, and Two cams 2a and 3a are required to regulate the strokes of the plungers 2 and 3, which increases the size of the pump and increases the cost.

In order to solve this problem, Japanese Patent Application Laid-Open No. 49-120203
The publication describes that a sub plunger is slidably fitted into a blind hole in the axial direction of the main plunger, a liquid chamber is formed between the sub plunger and the blind hole, and a worm wheel connected to the main plunger is fitted in the axial direction. Drill a hole in the
A rod whose one end faces the rear end of the auxiliary plunger is loosely engaged with this hole, and a camshaft linked to the accelerator lever is provided with two cams, a first and a second cam, and the other end of the worm wheel is connected to the first cam. to the cam,
An oil pump has been proposed in which the other end of the rod is brought into contact with a second cam so that the discharge characteristics can be changed depending on the load.

Such a structure has the advantage of being able to change the discharge characteristics of the oil pump depending on the load;
The actual structure is to insert a sub-plunger with a flange into the main plunger, a spring that biases the sub-plunger in the rod direction through the flange, and then connect and integrate the worm wheel with the rod inserted into the plunger. This complicates the manufacturing process and requires a special cam to operate the rod, resulting in an unavoidable complication of the structure.

(Means for Solving the Problems) The present application focuses on the fact that when the load increases in this type of plunger pump, the stroke itself of the plunger increases, and improves the structure by utilizing changes in the stroke according to the load. The first invention of the present application is made for the purpose of simplification, and the first invention of the present application is
A plunger is fitted into the housing so as to be rotatable and movable in the axial direction, and a worm wheel is provided at one end of the plunger to operate in conjunction with the plunger. The control cam is provided with a cam portion that comes into contact with the worm wheel, and the control cam is formed so as to increase the reciprocating distance of the plunger as the load of the engine changes from light to high, and the worm wheel is rotationally driven. reciprocating the part while slidingly contacting the control cam,
In an oil pump for an engine that discharges oil in a working chamber by reciprocating the plunger via a worm wheel, a first working chamber and a second working chamber having a larger diameter than the first working chamber are provided at the other end of the plunger. The distal end of a fixing member whose rear end is fixed and supported by the housing is slidably fitted into the first working chamber, and the inner hole is provided in the second working chamber on the same axis as the fixing member. A movable member is slidably fitted to the movable member, and the fixed member is provided with a regulating portion that restricts the stroke of the movable member to exceed a set value in the intake stroke, To provide an oil pump for an engine, characterized in that the second working chamber has a pumping action.

Further, the second invention of the present application is such that a plunger is rotatably and axially movably fitted in a housing, and a worm wheel is provided on one end side of the plunger and interlocks with the plunger, and the worm wheel is supported in the housing and is not affected by the load of the engine. The worm wheel is provided with a cam portion that comes into contact with the control cam that is rotated by a required angle in accordance with the engine load, and the control cam is formed so as to increase the reciprocating distance of the plunger as the load on the engine changes from light to high. In an oil pump for an engine, the cam portion is reciprocated while being in sliding contact with the control cam by rotationally driving a worm wheel, and the oil in the working chamber is discharged by reciprocating the plunger via the worm wheel, The plunger has a stepped shaft shape, and a first working chamber is formed between the stepped portion and the housing, while a second working chamber is coaxially formed at the other end of the plunger, and a second working chamber is formed coaxially with the other end of the plunger. The tip of a movable member is slidably fitted into the chamber, and a regulating member is fixed to the housing side for regulating the stroke of the movable member that exceeds a set value in the intake stroke, and a regulating member that regulates the stroke of the movable member that exceeds a set value in the intake stroke is fixed to the housing side. The present invention provides an oil pump for an engine, characterized in that a second working chamber has a pumping action.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figures 2 and 3 showing an embodiment of the first invention are the discharge top dead center under light load, Figure 4 is the suction bottom dead center under light load, and Figure 5 is the discharge top dead center under high load. Dead center, 6th point
The figures are cross-sectional views of the suction bottom dead center under high load.

In each figure, the oil pump has both ends covered with lids.
The housing 11 has a cylindrical body closed at 0.0 and 10. Inside the housing 11, there are formed a cam chamber 12 on the left in the figure, a worm wheel chamber 13 on the center, and a pump chamber 14 on the right. There is.

A pair of large diameter concentric cams 1 are provided in the cam chamber 12.
A camshaft 17 having a small diameter eccentric cam 16 is rotatably supported in a direction perpendicular to the axis between 5 and 15,
An accelerator pedal movement member 19 is provided at the end of the camshaft 17 that protrudes to the outside through the sealing material 18.
is fastened and fixed with a nut 20 so as not to rotate freely.

The accelerator pedal interlocking member 19 and the eccentric cam 16
The relationship is set so that the eccentric cam 16 is eccentric to the right position (Figs. 2 to 4) when the load is light, and eccentric to the left position (Figs. 5 and 6) when the load is high. .

A worm wheel 22 that meshes with the worm 12 that is interlocked with the rotation of the two-stroke engine is rotatably and axially movably fitted into the worm wheel chamber 13. Concentric cam 1 of the above camshaft 17
5, 15, and when rotated 90 degrees, the concentric cam 15,
A pair of chevron-shaped cams 23, 23 that fit between the chevron-shaped cams 23, 23 are provided, and for the chevron-shaped cams 23, 23,
A central stopper 24 in which the chevron cams 23, 23 fit between the concentric cams 15, 15 and stops against the eccentric cam 16 at the suction bottom dead center (Fig. 4) under light load.
and a peripheral stopper 25 that stops contacting the concentric cams 15, 15 at the suction bottom dead center (Fig. 6) under high load.
and.

Further, on the right side of the worm wheel 22, there is provided a coupling convex portion 26 that fits into a plunger 27, which will be described later.

A plunger 27 is fitted into the pump chamber 14 so as to be rotatable and movable in the axial direction, and a coupling recess 28 is provided on the left side of the plunger 27 into which the coupling projection 26 of the worm wheel 22 is fitted. A coil spring 30 is compressed between the right side of the plunger 27 and a ring member 29 that fixes and supports the rear end of a first piston 33 (to be described later) inserted through the plunger 27. The ring member 29 is stopped by the lid 10, and the plunger 27 is biased in the leftward movement direction by the coil spring 30, so that the coupling ring uneven portions 28, 26
The worm wheel 22 is also biased in the leftward movement direction via the biasing force, and the chevron-shaped cams 23, 23 are brought into contact with the concentric cams 15, 15 during the discharge stroke against the biasing force (Fig. 2,
5), and during the suction stroke, it is fitted between the concentric cams 15 and 15 by a biasing force (FIGS. 4 and 6).

The plunger 27 has a small-diameter first working chamber 31 inserted to approximately 2/3 depth from the right side, and a large-diameter second working chamber 3 inserted to approximately 1/3 depth from the right side.
2 are formed concentrically, and in the first working chamber 31, a first piston 33, which is fixedly supported by the housing 11 by the ring member 29 and constitutes a fixed member referred to in the present invention, is slidably mounted. The second working chamber 32 has an inner hole with which the first piston 3 is fitted.
3 is provided with a second piston 34 as a movable member according to the present invention whose outer periphery is slidably fitted into the second working chamber 32, and the inner hole of the second piston 34 is provided with a stepped portion of the first piston 33. 35 is provided with a shoulder portion 36 that is abutted against the shoulder portion 35. The stepped portion 35 of the first piston 33 constitutes a regulating member according to the present invention.

The plunger 27 is provided with a suction passage 37 and a discharge passage 38 communicating with the first working chamber 31, and also with a suction passage 39 and a discharge passage 40 communicating with the second working chamber 32. are passed through the middle part of the plunger 27 in a 180 degree symmetrical position, and the respective suction passages 37 and 39 are in the same phase, and the discharge passages 38 and 40 are in a 180 degree symmetrical position in the left and right parts of the plunger 27. Penetrate.

The housing 11 is provided with suction ports 42a and 42b that allow the suction passages 37 and 39 to coincide and communicate with the joint suction passage 41 in the housing 11 during the suction stroke of the plunger 27 (FIGS. 4 and 6).
On the other hand, during the discharge stroke of the plunger 27, the discharge passage 3
Discharge ports 43a, 43b whose numbers 8 coincide and communicate with the intake passage of the engine, and discharge ports 44a, 4 whose discharge passages 40 coincide with each other and communicate with the working chamber of the engine.
4b (Fig. 2, Fig. 5).

Each suction port 42a, 42b and each discharge port 43a, 4
3b, 44a, and 44b are set to have a phase difference of 90 degrees.

If the engine oil pump is configured as described above, when the engine is under a light load, the camshaft 17 is rotated by the accelerator pedal interlocking member 19 and the eccentric cam 16 is in the right position as shown in FIGS. 2 to 4.

The worm wheel 22 is rotated by the worm 21 which is linked to the rotation of the two-stroke engine, and during the discharge stroke, the chevron cams 23, 23 ride on the concentric cams 15, 15 against the biasing force of the coil spring 30 (Fig. 2), and then Coil spring 30 during the suction process
The angle-shaped cams 23, 23 are urged by the concentric cams 15,
15 (FIG. 4), the worm wheel 22 performs a reciprocating motion twice per revolution in combination with a rotational motion.

In the discharge stroke, the plunger 27 together with the worm wheel 22 is moved to the right in FIG. 4 and becomes the state shown in FIG. 4
0 coincides with the discharge port 44b, and the oil discharge is completed (Fig. 2, Fig. 13a, b).

However, when the engine is under a light load, the pressure inside the second working chamber 32 does not rise, as will be described later.
Even if the discharge passage 40 and the discharge port 44b match, oil is not discharged.

The plunger 27 together with the worm wheel 22
When rotated 90 degrees (Fig. 14), the worm foil 2
2, the plunger 27 is moved to the left, and the suction passage 37 of the first working chamber 31 coincides with the suction port 42a in Fig. 14c, and the suction passage 39 of the second working chamber 32 coincides with the suction port 42b in Fig. 14d. . By the way, in the suction stroke under light load, the first working chamber 31 is
Since the pressure is negative due to the relationship with the first piston 33, oil is sucked in by the amount that the plunger 27 moves to the left, while the second working chamber 32 has no change in volume because the second piston 34 moves to the left due to the negative pressure. Therefore, oil is not inhaled.

Next, when the plunger 27 is rotated 90 degrees (180 degrees from the beginning) together with the worm wheel 22 (FIG. 15), the plunger 27 is moved to the right together with the worm wheel 22, and the discharge passage 3 of the first working chamber 31 is rotated.
8 coincides with the discharge port 43b (FIG. 15a), and the discharge passage 40 of the second working chamber 32 coincides with the discharge port 44a (FIG. 15b), so that only the oil in the first working chamber 31 flows into the intake air of the engine. The water is supplied to the passageway (see A in Figure 12). This is because oil is sucked into the first working chamber 31 but not into the second working chamber 32 during the above-mentioned suction stroke.

Further, when the plunger 27 rotates 90 degrees (270 degrees from the beginning) together with the worm wheel 22 (Fig. 16), the plunger 27 and the worm wheel 22 are moved to the left from the state shown in Fig. 2, and the suction becomes the state shown in Fig. 4. The process is carried out (Fig. 16c,
d).

Next, when the plunger 27 rotates 90 degrees (360 degrees from the beginning) together with the worm wheel 22 (FIG. 13), the plunger 27 together with the worm wheel 22 is moved to the right from the state shown in FIG. 38 coincides with the discharge port 43a (FIG. 13a), and the discharge passage 40 of the second working chamber 32 coincides with the discharge port 44b (FIG. 13b), so that only the oil in the first working chamber 31 is supplied to the engine. The air is supplied to the intake passage (see A in Figure 12).

This operation is repeated thereafter.

On the other hand, when the engine is under high load, the
As shown in the figure, the camshaft 17 is rotated by the accelerator pedal interlocking member 19, and the eccentric cam 16 is placed in the left position, and the reciprocating stroke of the plunger 27 together with the worm wheel 22 is approximately doubled.

Then, when the plunger 27 rotates 90 degrees together with the worm wheel 22 from the discharge top dead center in FIG. 5 (FIG. 14), the plunger 27 and the worm wheel 22 are moved to the left with a stroke approximately twice that of the light load. 1 The suction passage 37 of the working chamber 31 is the suction port 4
2a (Fig. 14c), and the suction passage 39 of the second working chamber 32 corresponds to the suction port 42b (Fig. 14c).
Figure d). Therefore, during the suction stroke from the discharge top dead center in FIG. 5 to the suction bottom dead center in FIG. At the same time, the second piston 34 is sucked into the second working chamber 32 by the amount of leftward movement, and the second piston 34 moves to the left. 36 is stopped against the stepped portion 35 as a regulating member of the first piston 33 as a fixed member and its stroke is regulated, and then a negative pressure is created in relation to the second piston 34, so that the left side of the plunger 27 is Oil is sucked in by the amount of movement.

Next, when the plunger 27 rotates 90 degrees (180 degrees from the beginning) together with the worm wheel 22 (Fig. 15), the plunger 27 and the worm wheel 22 are moved to the right with a stroke approximately twice that of the light load, and the first working chamber is moved. 31 discharge passage 38 is discharge port 43
b (Fig. 15a), the discharge passage 40 of the second working chamber 32 corresponds to the discharge port 44a (Fig. 15b), and the oil in the first working chamber 31 is supplied to the intake passage of the engine. At the same time, the oil in the second working chamber 32 is supplied to the working chamber of the engine (see FIG. 12, c).

Furthermore, when the plunger 27 rotates 90 degrees (270 degrees from the beginning) together with the worm wheel 22 (FIG. 16), the plunger 27 is moved to the left together with the worm wheel 22, and the above-mentioned suction stroke is performed.

Next, when the plunger 27 rotates 90 degrees (360 degrees from the beginning) together with the worm wheel 22 (FIG. 13), the plunger 27 is moved to the right together with the worm wheel 22, and the discharge passage 3 of the first working chamber 31 is rotated.
8 coincides with the discharge port 43a (FIG. 13a), and the discharge passage 40 of the second working chamber 32 coincides with the discharge port 44b (FIG. 13b), and the discharge passage 40 of the second working chamber 32 coincides with the intake passage of the oil engine in the first working chamber 31. At the same time, the oil in the second working chamber 32 is supplied to the working chamber of the engine (see FIG. 12, c).

Figures 7 and 8 showing the embodiment of the second invention show the discharge top dead center under light load, Figure 9 shows the suction bottom dead center under light load, and Figure 10 shows the discharge top dead center under high load. FIG. 11 is a cross-sectional view of the suction bottom dead center under high load.

In each figure, a housing 11, a cam chamber 12,
The configurations of the worm wheel chamber 13, pump chamber 14, camshaft 17, worm 21, worm wheel 22, etc. are the same as in the embodiment of the first invention, and therefore their explanation will be omitted.

A plunger 50 is fitted into the pump chamber 14 so as to be rotatable and movable in the axial direction, while a second piston 51 as a movable member according to the present invention is slidably attached to the right side of the plunger 50. The disk 55 of the ring member 52 and the plunger 50 are fitted together.
A coil spring 30 is compressed between the housing 11 and the ring member 52 is held against the cover 10 of the housing 11.
The coil spring 30 urges the plunger 50 in the leftward movement direction.

The above worm foil chamber 13 (housing 11)
shows the right side of the worm wheel 22 and the housing 1.
A first working chamber 53 is formed between the first working chamber 53 and a second working chamber 53 that is inserted from the right side of the plunger 50 to a certain depth.
A working chamber 54 is formed. In the first working chamber 53, the worm wheel 22 acts as the first piston 33 in the embodiment of the first invention, and the second working chamber 54
is provided with a second piston 51 that is slidably fitted therein, and the second piston 51 is provided with a collar portion 56 that is abutted against the disc portion 55 of the ring member 52. Further, the second piston 51 is also slidably fitted into the disk portion 55. As is clear from the above, the disk portion 55 of the ring member 52
constitutes a regulating member that regulates the stroke of the second piston 51 as a movable member.

Note that the suction passage 37 and discharge passage 38 communicating with the first working chamber 53 of the plunger 50, and the second working chamber 54
A suction passage 39 and a discharge passage 40 leading to the housing 11, suction ports 42a, 42b, discharge port 43a,
43b, 44a, and 44b are the same as in the first embodiment.

Therefore, even with the above configuration, the same operations and effects as in the embodiment of the first invention can be achieved.

(Effects of the Invention) According to the first invention, by utilizing changes in the stroke of the plunger and regulating the stroke of the movable member that fits into the second working chamber, discharge characteristics according to the load can be realized. In addition, since it is basically only necessary to provide a fixed member and a movable member, the number of parts can be greatly reduced, and these members can be assembled extremely easily from the end side of the housing. , the manufacturing process can also be simplified.

According to the second invention, similarly to the above, by providing a regulating member that regulates the stroke of the movable member that fits into the second working chamber, it is possible to impart a pumping action to the second working chamber during high loads. , it is possible to realize discharge characteristics according to the load, and basically, it is only necessary to provide a movable member and a regulating member, so the number of parts can be significantly reduced, and these members are installed at the end of the housing. It can be assembled very easily from the side, and the manufacturing process can be simplified.

Further, in any of the inventions, since only one cam portion is required, the pump can be made smaller, contributing to cost reduction.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional plunger pump, FIGS. 2 to 6 are examples of an oil pump according to the first invention, and FIG. 2 is a sectional view of a light load and discharge top dead center.
Figure 3 is a sectional view of Figure 2 at a 90-degree turn position, Figure 4 is a sectional view of light load and suction bottom dead center, Figure 5 is a sectional view of high load and discharge top dead center, and Figure 6 is High load, sectional view of suction bottom dead center, FIGS. 7 to 11 are examples of the second invention, FIG. 7 is light load, sectional view of discharge top dead center, and FIG. 8 is the same as FIG. 90 degrees rotation position, Figure 9 is a cross-sectional view of light load, suction bottom dead center, Figure 10 is high load, discharge top dead center, Figure 11 is high load, suction bottom dead center. 12 is a graph of oil discharge characteristics of each example, FIG. 13a is a BB sectional view in FIG. 2, FIG. 13a is an AA sectional view in FIG. 2, and FIG. 13b is a sectional view taken along the line BB, FIG. 13c is a sectional view taken along the line CC, and FIG. 13d is a sectional view taken along the line DD. 11...Housing, 12...Cam chamber, 13...
... Worm foil chamber, 14... Pump chamber, 15...
... Concentric cam, 16 ... Eccentric cam, 21 ... Worm, 22 ... Worm foil, 23 ... Chevron cam, 27, 50 ... Plunger, 29, 52 ...
Ring member, 30... Coil spring, 31, 53...
...First working chamber, 32, 54...Second working chamber, 33
...First piston, 34, 51... Second piston, 37, 39... Suction passage, 38, 40... Discharge passage, 42a, 42b... Suction port, 43a, 4
3b, 44a, 44b...discharge port.

Claims (1)

[Scope of Claims] 1. A plunger is fitted in a housing so as to be rotatable and movable in the axial direction, and a worm wheel is provided at one end of the plunger to interlock with the plunger, and the worm wheel is supported in the housing and rotates as required according to the load of the engine. The worm wheel is provided with a cam portion that comes into contact with the control cam that is angularly rotated, and the control cam is formed so that the reciprocating distance of the plunger increases as the load on the engine changes from light to high;
In an oil pump for an engine, the worm wheel is rotationally driven to reciprocate the cam part while slidingly contacting the control cam, and the plunger is reciprocated via the worm wheel to discharge oil from the working chamber. , A first working chamber and a first working chamber are provided on the other end side of the plunger.
A second working chamber having a diameter larger than that of the working chamber is coaxially provided, and a distal end of a fixing member whose rear end is fixedly supported by the housing is slidably fitted into the first working chamber.
A movable member whose inner hole is slidably fitted to the fixed member is slidably fitted in the working chamber, and the above-mentioned regulating portion is provided to the movable member to regulate a stroke exceeding a set value in the suction stroke. An oil pump for an engine, characterized in that the oil pump is provided on a fixed member, and the second working chamber has a pumping action when the engine's set load is exceeded. 2. A control cam, which has a plunger fitted in the housing so as to be rotatable and movable in the axial direction, and a worm wheel that interlocks with the plunger is provided at one end of the housing, is supported in the housing and is rotated by a required angle according to the load of the engine. The worm wheel is provided with a cam portion that comes into contact with the worm wheel, and the control cam is formed so as to increase the reciprocating distance of the plunger as the load on the engine changes from light to high.
In an oil pump for an engine, the worm wheel is rotationally driven to reciprocate the cam part while slidingly contacting the control cam, and the plunger is reciprocated via the worm wheel to discharge oil from the working chamber. The plunger has a stepped shaft shape, and a first working chamber is formed between the stepped part and the housing, while a second working chamber is coaxially formed at the other end of the plunger, and a second working chamber is formed coaxially with the other end of the plunger. The tip of a movable member is slidably fitted into the working chamber, and a regulating member is fixed to the housing side to restrict the stroke of the movable member to exceed a set value in the suction stroke, and a regulating member is fixed to the housing side to restrict the stroke of the movable member to exceed a set value in the intake stroke. An oil pump for an engine, characterized in that a second working chamber has a pumping action.