JPS6311341Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to the improvement of an oil pump that has a built-in rotary reciprocating plunger and a reciprocating stroke control mechanism.It reduces the manufacturing cost of the pump itself, makes the pump smaller, and mounts it on the engine side. The aim is to reduce installation costs.

Conventionally, as shown in FIGS. 2 and 3, this type of oil pump 1' has a unique drive shaft (oil pump drive shaft) 6' inside the oil pump case 3' that is orthogonal to the plunger 8'. A worm gear 9' for applying rotational force to the plunger 8' is meshed with the worm 7' on the drive shaft 6' in the oil pump case 3' when the oil pump is used. is attached to a use position on the engine side, and a suitable rotating shaft interlocked with the crankshaft of the engine and the drive shaft 6' are connected by a shaft coupling, a drive gear 11', or other means. However, in that case, a drive shaft 6' that is perpendicular to the plunger 8' is required within the oil pump case 3', making the structure complicated. Therefore, an increase in cost is unavoidable, and the mounting mechanism tends to become complicated. The oil pump 1' shown in Figs. 2 and 3 is for separate oil supply of a two-stroke engine, and an oil pump drive shaft 6' is connected to the oil pump case 3' via a pair of bearings 4', 4'. The worm gear 9' of the rotary valve 3a, which is rotatably supported and supports the worm 7' on the shaft 6' and the plunger 8', is engaged, and by driving the shaft 6', the plunger 8' is rotated. It is a type that performs a pumping action by reciprocating. The plunger 8' is fitted into a cylinder provided in a rotary valve 3a which is rotatable within the case 3'.
It forms the operating part (pump chamber 6a) of the oil pump. The worm 7' serves as a driving mechanism for the plunger 8'. 10' is an oil seal disposed outside the bearing 4', 11' is a driving gear fixed to the shaft 6', and the gear 11' meshes with the gear on the crankshaft directly or via an idle gear. The case of the gear 11' is formed integrally with the crankcase, and the oil pump case 3' is fastened to the gear case with a plurality of bolts.

A shaft 15' is rotatably supported within a case 13' of the water pump 2' via a pair of grease-filled bearings 14', and an impeller 16' is attached to the tip of the shaft 15'. 17' is a mechanical seal, 18' is a water drain hole, 19' is a tightening nut, 20' is a pilot part, 21' is a connecting bolt, and 12' is a cover. Reference numeral 22' designates a coupling coupling, in which a tongue piece 23' provided at the tip of the shaft 6' engages with a groove 24' on the shaft 15' side to form a joint. Furthermore, as mentioned above, plungers and distributors are usually decelerated by a worm, etc., and therefore have two orthogonal axes inside the oil pump case, resulting in problems such as an increase in the size of the case.

In order to avoid the above-mentioned problems of conventional mechanical oil pumps, the present invention eliminates the drive shaft that is orthogonal to the plunger, and also protrudes a concentric gear part to the outside of the oil pump case to provide rotational force to the plunger. When the oil pump case is attached to another case fixed to the engine, that is, the mating case when the oil pump case is attached (expressed as another case in this invention), the gear part is fixed to the engine. It is designed to mesh with a drive gear on a rotating shaft that is linked to the engine's crankshaft within a separate case. That is, in the present invention, a rotary reciprocating plunger is provided outside the oil pump case, which has a built-in discharge rate control mechanism via a rotary valve that also serves as a bearing, and which is concentric and integral with the plunger for applying rotational force to the plunger. The gear part is made to protrude through the seal, and when the oil pump case is attached to the mounting seat that surrounds the hole in another case fixed to the engine, the gear part is placed on the rotating shaft that interlocks with the crankshaft of the engine within the other case. It is characterized by being designed to mesh with the drive gear.

Furthermore, as mentioned above, there are two methods for this type of oil pump: one is to completely incorporate it into the engine body as in the case of Japanese Utility Model Application No. 49-48286, and the other is to assemble a separate oil pump.

The former has drawbacks in terms of cost and performance, such as the need for highly accurate machining on a large body, the difficulty of installing a control cam, and the complicated machining of oil passages. Since it has the advantage of making the engine body compact when incorporated into a machine, it is used only for special applications such as chainsaws.

A separate oil pump, which is the object of the present invention, is used in many general-purpose engines and vehicle engines where oil consumption is important. By making the structure of this separate oil pump as described in the claims, the present invention provides an externally mounted oil pump that is easy to manufacture, inexpensive, extremely easy to assemble to the engine body, and has good metering performance. It is the purpose of this invention to provide. The present invention will now be described with reference to the drawings.

The oil pump 1 shown in Fig. 1 is for separate oil supply of a two-stroke engine.A rotary valve 3 is rotatably fitted in the central cylinder of an oil pump case 2, and a plunger is fitted in the central cylinder of the rotary valve 3. 4 are fitted in a reciprocating manner. That is, both ends of a diametrical valve drive pin 5 fixed to the plunger 4 are fitted into longitudinal slits (not shown) of the rotary valve 3;
Therefore, the rotation of the plunger 4 is transmitted to the rotary valve 3 via the pin 5, and the plunger 4 can reciprocate with respect to the rotary valve 3. A suction port 7 opens into a pump chamber 6 formed between the rotary valve 3 and the plunger 4, and the pump chamber 6 is connected to a discharge port 9 through a passage 8 within the rotary valve 3. Therefore, when the plunger 6 descends to increase the volume of the pump chamber 6, oil enters the pump chamber 6 from the suction port 7, and when the plunger 4 ascends, the oil is pressurized and forced out to the discharge port 9. Plunger 4 is a disk-shaped end cam 1
0, an annular lead 11, and a worm gear 12 are integrally and concentrically provided. The outer circumferential surface of the end cam 10 is slidably and rotatably fitted to the inner surface of the cylinder in the oil pump case 2 in the same way as the rotary valve 3, and the end surface on the worm gear 12 side (bottom surface in FIG. 1)
There are two chevron-shaped cams on the same circumference that protrude smoothly downward, one of which is visible in Figure 1, and the other one is located on the back side of Figure 1 at an angle of 180 degrees. They are arranged in phase difference. Since a spring 19 is compressed between the end cam 10 and the rotary valve 3, the end cam 10 is urged downward, and the disc-shaped cam 1 on the control cam shaft 13
It faces the outer peripheral cam surface of No. 4. The lower end surface of the lead 11 is attached to the eccentric pin 15 by the elasticity of the spring 19.
The plunger 4 elastically abuts against the upper end of the cylindrical surface of the plunger 4, so that the plunger 4 cannot move downwardly during rotation beyond the illustrated position limited by the eccentric pin 15. The control cam shaft 13 is rotatably supported by the oil pump case 2 via a pushbutton, and as described above, the control cam shaft 13 is provided with a disk-shaped cam 14 and an eccentric pin 15 inside the oil pump case 2, and outside the oil pump case 2. A lever 16 is fixed to the protrusion. Therefore, by operating the lever 16 with the throttle lever via the cable, the control camshaft 1
3 can be rotated. Since the center line of the pin 15 is eccentric to the center line of the control cam shaft 13, when the control cam shaft 13 is rotated, the vertical position of the eccentric pin 15 changes slightly, changing the position of the bottom dead center of the plunger 4. , the vertical stroke (amount of movement) of the plunger 4 can be regulated. That is, when the control camshaft 13 is rotated by operating the lever 16 to lower the position of the eccentric pin 15, the end cam 10 comes into contact with the cam 14 over the entire circumference, so that the plunger 4 reciprocates once at the maximum stroke every half rotation. When the eccentric pin 15 is raised by operating the lever 16, the end cam 10 is also raised by the same amount via the lead 11, and the lower part of the end cam 10 is lifted from the outer peripheral surface of the cam 14 as shown in FIG. On the other hand, the angular range in which the end face cam 10 is in contact is reduced, and the vertical stroke of the plunger 4 is reduced accordingly, and in this way, the stroke of the plunger 4 can be controlled by operating the lever 16. Worm gear 1
The shaft of No. 2 passes through the seal 17 and protrudes from the case 2,
Worm 19 provided on water pump shaft 18
meshes with The oil pump case 2 integrally includes a cylindrical boss 20 and an outward flange 21 around the seal 17. The cylindrical boss 20 fits into a hole 23 formed in the water pump 22, and the flange 21 is connected to a flat mounting seat 24. A plurality of bolts 25 are used to tighten the screws. 26 is a cover. Lever 16 is connected via a cable to a throttle lever (both not shown).

The water pump case 22 is fastened to the crankcase by a plurality of bolts, for example, on a vertical mounting surface parallel to the plane of the drawing. A pair of bearings 28, 28 fixed in the water pump case 22 supports the water pump shaft 18, and a driving gear 29 fixed to the left end of the shaft 18 is connected directly or via an idle gear to the crankshaft. meshes with the gear. A gear case portion 30 provided in the crankcase and water pump case 22 is closed with a cover 32 by a plurality of bolts 31, and the oil stored in the gear case portion 30 is transferred to the driving gear 29.
The particles are scattered, pass through the bearing 28 , and are supplied to the meshing portion between the worm gear 12 and the worm 19 . An impeller 34 fixed to the right end of the water pump shaft 18 is covered with a cover 35. An inlet 36 of the cover 35 connects to the radiator and an outlet 37 connects to a water jacket in the crankcase. Furthermore, 38
is an oil seal, 39 is a mechanical seal, 40 is
41 is a water drain hole, 41 is a fuel pump, 42 is a fuel pump drive lever, 43 is an eccentric cam with which the tip of lever 42 is in contact, 44 is a fuel inlet, and 45 is a fuel outlet.

During engine operation, part of the engine output is transmitted to the impeller 34 through the drive gear 29 and shaft 18, and the cooling water introduced from the inlet 36 is pressurized by the impeller 34 and then flows from the outlet 37 into the water jacket of the engine. supplied to A part of the rotational force of the shaft 18 is transmitted to the plunger 4 through the worm 19 and the worm gear 12, and the plunger 4 repeats reciprocating motion by the action of the cams 10 and 14 while rotating as in the conventional case, and drains the oil. Performs a pumping action to force feed. That is, when the plunger 4 rotates,
The end face 10 comes into sliding contact with the cam 14 and moves up and down twice during one rotation. When the downward protrusion of the end cam 10 is lifted up onto the cam 14, the plunger 4 rises together with the end cam 10, and the plunger 4 moves upward to the suction port 7.
When the oil in the pump chamber 6 rises further after closing, the oil in the pump chamber 6 starts to be pressurized, and at that time, the passage 8 communicates with the discharge port 9, and the pressurized oil is discharged toward the projecting port 9 (discharge stroke). The rotary valve 3 rotates together with the plunger 4 to close the passage 8 to the discharge port 9.
When the lower protrusion of the end cam 10 passes the cam 14, the plunger 4 descends, and the plunger 4 opens the suction port 7, thereby replenishing the pump chamber 6 with another oil (suction stroke). As the plunger 4 moves upward, it is pressurized as described above. The amount of oil discharged is controlled by operating the lever 16. That is, when the control camshaft 13 is rotated by the lever 16 and the eccentric pin 15 is raised, the end cam 10 is lifted from the cam 14 within a predetermined angle range, the vertical stroke of the plunger 4 is reduced, and the amount of oil discharged is reduced. When the eccentric pin 15 is lowered, the contact angle range of the end cam 10 with respect to the cam 14 increases, and as the vertical stroke of the plunger 4 increases, the amount of oil discharged also increases. The pressurized oil is supplied from the discharge port 9 to the engine's crank bearing, cylinder, sliding surfaces between pistons, and the like.

As explained above, according to the present invention, compared to conventional mechanical oil pumps of this type, there is no unique drive shaft inside the oil pump case 2, so the production cost of the oil pump itself is significantly reduced, and the pump also Downsize. Furthermore, in the present invention, the plunger 4 is supported by the oil pump case 2 via the rotary valve 3 which also serves as a bearing, so the rotary valve 3 provides a long bearing surface for the plunger 4, and therefore the plunger 4
The worm gear 12 can be supported sufficiently stably even if the extended shaft part of the oil pump case 2 is cantilevered outward from the oil pump case 2 and the gear part (worm gear 12) is integrally provided at the tip. There is no need to provide a bearing separate from the valve 3, and the structure is greatly simplified. Furthermore, since the seal 17 is provided in the cylindrical boss 20 portion of the oil pump case 2 where the plunger 4 protrudes outward from the oil pump case 2, the oil pump 1
Even when transporting and assembling the oil pump 1 alone, there is no risk of foreign matter entering the oil pump 1 from the outside.
There is no fear that the oil in the oil pump 1 will flow out after the oil pump 1 is mounted on the mounting seat 24 as shown in FIG. Moreover, the seal 17 plays the role of a buffer material that effectively suppresses the vibration of the cantilevered worm gear 12 in the vicinity of the worm gear, and even though the plunger 4 is pivotally supported only by the rotary valve 3, the oil pump 1 This has the advantage of stably maintaining ejection performance. Of course, since the plunger 4 and the worm gear 12 are concentric and integral, the number of parts is minimized and costs are reduced. In addition, a worm 19 is provided on the water pump shaft 18 which is essential for driving the impeller 34 in the water pump, and a worm gear 12 protruding from the oil pump case 2 is engaged with the worm gear 19 at the same time as the oil pump case 2 is installed. Adopting a structure that allows the oil pump to be installed becomes easier.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a mechanical oil pump to which the present invention is applied, FIG. 2 is a vertical cross-sectional view showing an example of a conventional structure, and FIG. 3 is a cross-sectional view of the same. 2...Oil pump case, 4...Plunger, 12...
... Worm gear (gear part), 18 ... Water pump shaft (rotating shaft), 19 ... Worm (drive gear).

Claims (1)

[Scope of utility model registration request] A gear part concentric and integral with the plunger for applying rotational force to the plunger is protruded through a seal from the outside of the oil pump case, which has a discharge rate control mechanism built in with a rotating reciprocating plunger via a rotary valve that also serves as a bearing. When the oil pump case is attached to the mounting seat that surrounds the hole in another case fixed to the engine, the gear part engages with the drive gear on the rotating shaft that is linked to the engine crankshaft in the other case. An oil pump characterized by being made to fit.