EP0786047A1

EP0786047A1 - Device with fuel injection and with a lubricant-supply unit for internal-combustion engines

Info

Publication number: EP0786047A1
Application number: EP96927669A
Authority: EP
Inventors: Ronald Uhlig; Andreas Singer; Klaus Matthees; Peter Schulz
Original assignee: Dolmar GmbH
Current assignee: Makita Engineering Germany GmbH
Priority date: 1995-08-10
Filing date: 1996-08-02
Publication date: 1997-07-30
Anticipated expiration: 2016-08-02
Also published as: DE19529368C1; WO1997006359A1; US5787854A; DE59605397D1; EP0786047B1; AU6741596A

Abstract

The invention concerns a device with fuel injection and with a lubricant-supply unit for internal-combustion engines, preferably hand-held tools such as chain saws. The device has a worm gear (12) mounted on a crankshaft (11) or driven by the crankshaft (11), the worm gear engaging with a mating wheel (13) which drives the lubricant pump (16). A piston (17) in the lubricant pump (16) acts as a trunnion for the mating wheel (13) and has an inclined face (18) which rests against a lifting pin (20) adjustably held in the casing and used to regulate the delivery rate of the lubricant pump (16). In order to produce a compact design, preferably for a chain saw with several, if necessary adjustable, lubrication circuits and with a high-pressure fuel supply, the invention proposes that the worm gear (12) engages with two mating wheels (13, 14) each of which is mounted on a crankshaft for a lubricant pump (16, 31) and/or a fuel pump (27).

Description

Device with fuel injection and lubricant delivery device for internal combustion engines

field of use

The device with fuel injection and lubricant delivery device for internal combustion engines can be used wherever a compact arrangement for such a device is to be created, preferably in the case of a chain saw with a plurality of lubrication circuits which can also be regulated if necessary and a fuel delivery with higher pressure.

The invention relates to a device with fuel injection and lubricant delivery device for internal combustion engines, preferably for hand-operated tools, such as chainsaws, with a helical gear arranged on a crankshaft or driven indirectly by the crankshaft, which meshes with a counter gear for driving the lubricant pump. wherein a piston of the lubricant pump forms a bearing journal for the counter wheel and has an oblique end face which bears against a lifting pin which is held in an adjustable manner, by means of which the delivery rate of the lubricant pump can be adjusted.

ORIGINAL DOCUMENTS State of the art

In the case of hand-held chain saws, mainly piston pumps controlled by a valve have proven their worth for lubricating the cutting chain. The oil pump in question has a cylindrical pump chamber formed in a pump housing with an inlet opening and an outlet opening and a pump piston rotatable in this pump chamber via a gear formed by a helical gear and a counter gear, which is resiliently supported on one side and an end face on the other side Inclined surface which bears against a lifting pin arranged eccentrically to the piston longitudinal axis, so that when the piston rod rotates, an axial movement is generated which is used for pumping. The axially adjustable stop allows different strokes of the pump piston to be set. This lubricant delivery device is usually flanged to the internal combustion engine as an auxiliary unit block together with the fuel injection.

From DE 37 35 711 AI is a portable, hand-operated tool driven by a two-stroke engine, such as a chain saw or the like, with a pneumatically driven injection pump for injecting fuel and an intake pipe for the combustion air, and a low-vibration handle housing for carrying and guiding of the implement is known, in which the injection pump is arranged separately from the two-stroke engine in the handle housing and is connected to the two-stroke engine via flexible connections. From DD-PS 41 648 lubricant pumps for internal combustion engines are known which have two rotating piston delivery units arranged one behind the other. These perform the constant stroke of a high-speed gearbox geared down to the engine speed. The first delivery unit supplies the lubricant and the second supplies the fuel. Both media are mixed and fed to the internal combustion engine, which is designed as a two-stroke engine.

Task, solution, advantages

It is an object of the present invention to provide a compact arrangement for the device mentioned at the outset, preferably in the case of a chain saw with a plurality of lubrication circuits, which can also be regulated if necessary, and a fuel requirement with higher pressure.

This object is achieved by the device specified in claim 1. It is provided that the helical gear is in engagement with two counter gears, each of which is connected to a drive shaft for a respective lubricant and / or a fuel pump. With this device, the fuel injection and / or lubricant delivery devices are effectively combined in the smallest of spaces, the crankshaft being used as the drive element.

Further developments of the device according to the invention are described in the subclaims. So they can be aligned in parallel or in a V-shape with the crankshaft via the gear for the lubricant and / or fuel pump consisting of the helical gear and the counter gears. In essence, the most favorable shape design for the device in question can be selected as an auxiliary unit.

According to a first embodiment variant of the device according to the invention, one of the counter wheels is assigned a delivery unit for lubricants on both sides, the two delivery units preferably being able to be driven by a lifting disk on one of the delivery units. The aforementioned oblique face of the piston rod serves as the lifting disk here. In order to be able to transport different delivery quantities through the delivery units mentioned, the delivery units for the lubricant have effective piston surfaces of different sizes. In this case, the other counter wheel preferably drives the fuel pump, which is also designed as a plunger pump.

As an alternative to this, a delivery unit can be assigned to one of the counter wheels on both sides, of which one of these delivery units is a continuously operating fuel pump and the other delivery unit is a lubricant pump which is adjustable in the delivery rate. The simplest possibility for a stroke adjustment of the conveyor unit is that the lifting pin serving as a stop is connected to an adjusting screw which can be rotated in a thread fixed to the housing and with which the axial position of the lifting pin can be individually adjusted. Likewise, it is possible to change the radial position of the lifting pin with respect to the longitudinal axis of the piston of the pump via an adjusting device. In the embodiment described above, a fixedly adjustable lubricant pump is preferably assigned to the other counter wheel (on the opposite side of the crankshaft). For the controllable lubricant pump, which is arranged on the same side as the fuel pump, an axis above the axes of the counter wheels, which is preferably transverse to the crankshaft axis, is suitable as the location for the actuating unit.

According to a further embodiment of the invention, the counter wheel driving the fuel pump is guided axially on both sides in the housing block; the same applies to the counter wheel driving the lubricant delivery device. The piston or the lifting disk of the controllable lubricant pump and / or the fuel pump is preferably in rotation with the associated counterwheel, but can be pushed in engagement. Finally, all lubricant pumps can be designed as controllable delivery units.

Brief description of the drawings

Several exemplary embodiments of the invention are explained in more detail below with the aid of schematic drawings. Show it: Fig. 1 to 3 in cross section to the crankshaft axis each have different versions of the device according to the invention.

Detailed description of the invention and best way to carry out the invention

The devices shown in FIGS. 1 to 3 each have in a housing 10 a helical gear 12 which is arranged on the crankshaft 11 and which engages on opposite sides with counter gears 13 and 14. The counter wheel 13 drives the lubricant pump 16 arranged in the housing part 15 via its drive shaft 17, the drive shaft 17 simultaneously forming the piston of the lubricant pump 16 as the bearing journal for the counter wheel 13. This piston has a face-side inclined surface 18 as a lifting disk, which bears against a lifting pin 20 held in the housing 15 via an adjusting screw 19. When the counter wheel 13 rotates, the drive shaft 17 carries out oscillating up and down movements, as a result of which the oil (see FIG. 1) conveyed into the inlet connections 21, 22 is pressed under pressure into the outlets 23, 24. During this oscillating movement, the drive shaft is supported by the spring 25. In the exemplary embodiment shown in FIG. 1, two drive units 161 and 162 forming the lubricant pump 16 are thus formed by the drive shaft 17, the pumping action of which is different due to the different effective piston surfaces. In a corresponding manner, the drive shaft 26 forms a bearing journal for the counter wheel 14 on the opposite side and is used to drive a fuel pump 27, the delivery unit 28 of which sucks in fuel via the inlet connection 29 and pumps it into the outlet connection 30. The two drive shafts for the lubricant pump 16 and the fuel pump 27 are aligned parallel to one another. This results in a compact, dense construction, which is advantageous in internal combustion engines for hand-operated tools. Alternatively, it would also be possible to arrange the drive shafts 17 and 26 in a V-shape with respect to one another.

In a corresponding manner, in the unit block shown in FIG. 2, the helical gear 12 is driven by the crankshaft 11 and engages in the counter gears 13, 14. Here, too, the drive shaft 17 serves as a journal for the counter wheel 13. The drive shaft 17 is part of a lubricant pump 16 which conveys the lubricant into the outlet connection 23 via the inlet 21. Corresponding identical parts, such as the lifting disk 18, the lifting pin 20 and the adjusting screw 19 and the spring 25, are identified by the same reference numerals as in FIG. 1. On the opposite side, the counter gear 14 and the drive shaft 26 serve both to drive the fuel pump 27 and to drive the lubricant pump 31, which is arranged above the fuel pump 27. The drive shaft 26 has at its upper end an inclined surface on the front side and serving as a lifting disk 32, which acts against an adjustable lifting pin 33 is present. An adjusting unit 34, which can be operated via a manual actuating lever 35, is used to adjust the lifting pin in the longitudinal axial direction of the drive shaft 26. The piston 36, which is part of the drive shaft 26, conveys lubricant entering the outlet 38 via an inlet 37 in a manner known from the prior art for plunger pumps. According to the construction, the actuating unit 34 is arranged above the drive shafts 17 and 26 and transversely to the longitudinal axis of the crankshaft 11.

In the device shown in FIG. 3, which is constructed in accordance with the device according to FIG. 2, the adjustable actuating unit 34 for regulating the pump delivery rate of the lubricant pump 16 is arranged below the counter gears 13 and 14, while the adjusting screw 19 for the axial displacement of the previously described one Lift pin 33 and thus serves to regulate the flow rate of the lubricant pump 31. This device, which is designed as an auxiliary unit block of an internal combustion engine, in particular for two-stroke engine chain saws, is also of compact design and utilizes the energy available due to the rotation of the crankshaft during engine operation, using only a few components.

Reference symbol list;

Housing 10

Crankshaft 11

Helical gear 12

Counter wheels 13, 14

Housing part 15

Lubricant pump 16

DRIVE WAY 17

Sloping surface 18

Adjustment screw 19

Lift pin 20

Inlet port 21, 22nd

Outlets 23, 24

Spring 25

DRIVE WAY 26

Fuel pump 27

Conveyor unit 28

Inlet port 29

Outlet connector 30

Lubricant pump 31

Lifting disc 32

Lift pin 33

Actuator 34

Operating lever 35

Piston 36

Inlet 37

Outlet 38

Conveying units 161, 162

Claims

Expectations:

1. Device with fuel injection and lubricant delivery device for internal combustion engines, preferably for hand-operated tools, such as chainsaws, with a helical gear (12) arranged on a crankshaft (11) or driven indirectly by the crankshaft (11), which has a counter gear ( 13) for driving the lubricant pump (16) is engaged, a piston (17) of the lubricant pump (16) forming a bearing journal for the counter wheel (13) and having an oblique end face (18) which is adjustable against a lifting pin held in the housing (20) is applied, via which the delivery rate of the lubricant pump (16) is adjustable, characterized in that the helical gear (12) is in engagement with two counter gears (13, 14), each of which has a drive shaft (17, 26) for each a lubricant (16, 31) and / or a fuel pump (27) is connected.

2. Device according to claim 1, characterized in that the drive shafts (17, 26) for the lubricant (16, 31) and / or fuel pump (27) are aligned parallel or V-shaped to one another.

3. Apparatus according to claim 1 or 2, characterized in that one of the counter wheels (13) on both sides one Conveying unit (161, 162) for lubricants is assigned, wherein preferably both conveying units (161, 162) can be driven by a lifting disk (18) on one of the conveying units (162).

4. The device according to claim 3, characterized in that the conveyor units (161, 162) for lubricants have different sized effective piston surfaces.

5. Device according to one of claims 1, 2 or 4, characterized in that one of the counter wheels (14) is assigned on both sides to a delivery unit, of which one of these delivery units as a continuously operating fuel pump (27) and the other delivery unit an adjustable in the delivery rate Lubricant pump (31).

6. The device according to claim 5, characterized in that the other counter wheel (13) is assigned a permanently adjustable lubricant pump (16).

7. The device according to claim 5 or 6, characterized in that the actuating unit (34) for the controllable lubricant pump (31) is arranged in an axis above the axes of the counter wheels (13, 14), preferably transversely to the crankshaft axis.

8. Device according to one of claims 5 to 7, characterized in that the fuel pump (27) and / or the lubricant delivery device (16, 31) driving counter wheel (13, 14) is guided axially on both sides in the housing block (10, 15).

9. Device according to one of claims 5 to 8, characterized in that the piston (36) or the lifting disc (32) of the controllable lubricant pump with the associated counter wheel (14) is rotatably but slidably engaged.

10. Device according to one of claims 1 to 9, characterized in that all lubricant pumps (16, 31) are designed as controllable delivery units.