WO2007144074A1

WO2007144074A1 - Internal combustion engine, particularly for a tool

Info

Publication number: WO2007144074A1
Application number: PCT/EP2007/004846
Authority: WO
Inventors: Herbert Hüttlin
Original assignee: Huettlin Herbert
Priority date: 2006-06-14
Filing date: 2007-06-01
Publication date: 2007-12-21
Also published as: DE102006027953A1

Abstract

The invention relates to an internal combustion engine, particularly for a tool, with a housing in which a first and a second piston (22, 24) are arranged, the end surfaces of which face each other, thus defining a work chamber (36) between them, wherein the pistons (22, 24) can turn around a rotational axis (26) in the housing (12) and perform to-and-fro movements in opposite directions, wherein the rotational axis (26) passes through the work chamber (36), and wherein the rotational axis (26) is essentially vertical when mounted in the internal combustion engine (10) of the tool, and the pistons (22, 24) are essentially in a horizontal position, and wherein a shaft (50), that is connected to the pistons (22, 24) in a torque-proof manner, is arranged on the rotational axis (26), and wherein said shaft (50) protrudes downwards from the housing (12) below the pistons (22, 24).

Description

Internal combustion engine, in particular for a working device

The invention relates to an internal combustion engine, which is used in particular in a working device.

The invention further relates to a working device with such an internal combustion engine.

An implement in which the internal combustion engine according to the invention can be used is in particular a lawnmower or a brushcutter. The invention will be described below with reference to the preferred application of an internal combustion engine in a lawnmower, without the present invention being limited thereto. In a lawnmower, the internal combustion engine serves to set the cutting blade in rotation. In conventional lawn mowers designed as internal combustion engines as reciprocating engine gasoline engines are used, which are designed as two-stroke engines or four-stroke engines. Usually, the gasoline engine lawn mowers is a single-cylinder engine.

In lawnmower engines, one piston and the associated cylinder are disposed horizontally, i. The linear movements of a reciprocating carried out in the working device installed state of the internal combustion engine in a substantially horizontal plane. The drive shaft connected to the cutting blade, on the other hand, is arranged perpendicular to the direction of movement of the one piston, i. standing or vertical. This results in the problem that the linear horizontal movement of the one piston must be converted into a rotation of the cutting blade to the vertical drive shaft. To implement the reciprocating motion on the rotation of the output shaft about a vertical axis of rotation, a crank gear is needed, the crank rod connects between the crankshaft and the piston to convert the reciprocating motion of the piston in a rotational movement of the crankshaft or drive shaft.

From DE 103 61 566 A1, by contrast, an internal combustion engine designed as an oscillating piston engine is known, which has a total of four pistons in a substantially spherical housing which rotate together about an axis of rotation about the housing, two of the four pistons in each case with respect to the center of the housing approximately diametrically opposed piston form a rigid pair of pistons, wherein the two pairs of pistons are reciprocally pivotable in opposite directions about a common, approximately perpendicular to the axis of rotation pivot axis. The two pairs of pistons are arranged crosswise with respect to the pivot axis, so that in each case two pistons of the piston pairs face with their piston working surfaces in order to form therebetween a working chamber, in each of which a Carnot cycle takes place. Such a spherical motor with swivel piston is less suitable for installation in a lawnmower because of its size. The invention is therefore based on the object to provide an internal combustion engine for a working device, which is structurally simple, inexpensive to produce, requires little installation space, and in particular allows the elimination of a crank mechanism.

According to the invention this object is achieved by an internal combustion engine, in particular for a working device, with a housing in which a total of a first and a second piston are arranged, which define a working chamber between their facing end surfaces, wherein the pistons about an axis of rotation in the housing can rotate and thereby perform mutually opposite reciprocating movements, wherein the axis of rotation passes through the working chamber, and wherein the axis of rotation in the installed state of the internal combustion engine is substantially vertical and the pistons are arranged substantially horizontally, and wherein on the axis of rotation a rotatably connected to the piston shaft is arranged, which is led out below the piston from the housing down.

The internal combustion engine according to the invention is based on a rotary piston machine principle, in which the two pistons not only execute reciprocating movements, but at the same time rotate around a common axis of rotation. The two pistons are arranged lying in the housing, and the axis of rotation, which is to be understood here as a geometric axis, extends in the installed state of the internal combustion engine substantially vertically. The reciprocal movement of the two pistons, which is opposite to one another, mediates the working cycles of the intake, compression, expansion and ejection. The circulating movement of the two pistons about the common axis of rotation now has the advantage that the shaft, which is non-rotatably connected to the piston with respect to the axis of rotation, can be set in rotation about the axis of rotation of the pistons around the axis of rotation, likewise about the vertical axis of rotation so that no crank gear is needed between the two pistons and the shaft to drive the cutting blade of a lawnmower. The rotational movement of the shaft is in fact tapped directly from the rotational movement of the piston about the axis of rotation. Furthermore, in the internal combustion engine according to the invention two pistons are provided, which follow the principle of a boxer engine in opposite directions to perform their movements, whereby the individual stroke of the piston can be reduced compared to a single-piston engine, but the total stroke for the working process in the working chamber (compression / Expanding) is not less than in an internal combustion engine with only one reciprocating piston.

The internal combustion engine according to the invention is thus very space-saving and structurally simple and thus inexpensive to produce with comparable performance.

The internal combustion engine according to the invention forms a portal engine with overhead piston and arranged therebelow, substantially vertical drive / output shaft, which does not require Karbolgetriebe for operating a working device.

In a preferred embodiment, when the pistons revolve around the axis of rotation, they reciprocate pivoting movements about a pivot axis which runs perpendicular to the axis of rotation and rotates with the pistons about the axis of rotation.

In this embodiment, the oscillating piston principle is additionally used, so that the two pistons pass through a relative to the pivot axis to this concentric curved trajectory. One advantage of this embodiment is that the two pistons are moved back by gravity into their BDC position (bottom dead center position) when no centrifugal force acts on the pistons due to the rotation about the axis of rotation, as is the case with the internal combustion engine ,

In the context of the aforementioned embodiment, the pistons are arcuate with the pivot axis substantially concentric curvature.

In contrast to the oscillating piston engine according to DE 103 61 566 A1, the pistons are accordingly not designed as ball wedges, but as curved cylindrical pistons. See body, which results in the advantage of a low construction in the vertical direction of the piston.

In an alternative to the oscillating piston principle, it is provided in a further preferred embodiment that the pistons, when circulating about the axis of rotation, execute linear movements which are directed in a V-shape obliquely to the axis of rotation.

In this embodiment, therefore, the pistons perform linear movements, which has the advantage that the pistons themselves may be straight, i. have no curvature, and thus are easier to produce. The V-shaped obliquely directed to the rotational axis of the linear movement of the two pistons is preferably such that the TDC position (top dead center position) of the piston, in which the working chamber has minimal volume (ignition timing), the upper position, while the then both pistons are moved back to the UT position by gravity support when the engine is running at low speed or stationary.

In a further embodiment, which is similar to the aforementioned embodiment, the pistons, when circulating around the axis of rotation, execute linear movements which are directed perpendicular to the axis of rotation.

In this embodiment, the direction of movement of the two pistons is therefore just as in the known reciprocating engines for lawn mowers, which has the advantage that the internal combustion engine has the lowest height in this embodiment.

In a further preferred embodiment, which is advantageous for all the aforementioned embodiments, the pistons are circular or oval in cross-section perpendicular to their direction of movement. In particular, a circular cross-sectional configuration of the piston has the advantage that for sealing the piston against the working chamber circular seals can be used, so that can be used on proven sealing concepts of reciprocating engines.

In a further preferred embodiment, a control mechanism is provided for deriving the reciprocating movement of the piston from the orbital movement about the axis of rotation, which has a cam extending around the axis of rotation, arranged in each case at least one on each piston on its side facing away from the working chamber Running organ is running.

Depending on whether the two pistons perform pivoting movements about a pivot axis or linear movements obliquely or perpendicular to the axis of rotation, the curve of the control curve is shaped accordingly.

In one embodiment of the internal combustion engine with a rotary piston and in an embodiment of the internal combustion engine with linear movements directed obliquely to the axis of rotation, the control curve is not in a plane perpendicular to the axis of rotation, but has wave peaks and troughs with respect to the horizontal.

In one embodiment of the internal combustion engine, in which the pistons perform linear movements perpendicular to the axis of rotation, the control cam lies in a horizontal plane and has an elliptical contour in order to derive the reciprocating linear movements from the orbital motion of the pistons about the axis of rotation.

In a further preferred embodiment, at least one inlet for air and / or fuel, an outlet for combusted fuel-air mixture and optionally a spark plug are arranged on one side of the housing facing the working chamber. The abovementioned functional parts are thus advantageously arranged to save space on the upper side of the housing near the axis of rotation, since the working chamber is arranged around the axis of rotation as described above and symmetrically to the latter.

The internal combustion engine according to the invention is preferably used for driving a cutting blade of a lawnmower.

The internal combustion engine according to the invention is furthermore preferably used for driving a cutting element of a brushcutter.

An inventive implement, in particular lawn mower or brushcutter, is equipped with an internal combustion engine according to the invention.

It is also conceivable and possible within the scope of the present invention that the working device is also a small vehicle, in particular a small sports vehicle, such as a go-kart, in which the internal combustion engine according to the invention can be used as a drive. It is already known to use conventional lawnmower motors for driving go-karts.

Further advantages and features will become apparent from the following description and the accompanying drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Embodiments of the invention are illustrated in the drawings and will be described in more detail with reference to this. Show it: Fig. 1 is a side perspective view of an internal combustion engine for a

Implement, in particular a lawnmower, with parts of the implement and with the housing closed;

Fig. 2 is a vertical longitudinal section through the internal combustion engine in Figure 1, wherein the two pistons are in the TDC position.

FIG. 3 shows a vertical longitudinal section through the oscillating-piston machine in FIG. 1 rotated by approximately 90 ° with respect to FIG. 2, the pistons being in the UT position; FIG.

Fig. 4 shows another embodiment of an internal combustion engine for a

Working device in a vertical longitudinal section, which is comparable to Figure 2;

FIG. 5 shows a vertical longitudinal section through the internal combustion engine in FIG. 4 in a representation comparable to FIG. 3; FIG.

6 shows a still further embodiment of an internal combustion engine for a working device in a vertical longitudinal section in a representation comparable to FIG. 2; and

Fig. 7 is a longitudinal section through the internal combustion engine in Fig. 6 in a with

Fig. 3 comparable representation, with further parts of a working device are shown.

In Fig. 1 to 3, a first embodiment of an internal combustion engine 10 according to the invention is shown.

The internal combustion engine 10 is shown for an application in an implement which is a lawnmower. Such a lawnmower has a cutting blade 11, such as it is known for lawnmowers. Other parts of the lawnmower are not shown in Fig. 1 to 3.

The internal combustion engine 10 generally has a housing 12 which is formed by an upper housing part 14, a middle housing part 16 and a lower housing part 18.

The housing parts 14, 16 and 18 are clamped or screwed together via a plurality of clamping screws 20.

In the housing 12, a first piston 22 and a second piston 24 are arranged. The pistons 22 and 24 are located in the upper part of the housing 12. The pistons 22 and 24 are arranged in particular lying in the housing 12.

In operation of the internal combustion engine 10, the pistons 22 and 24 run together about a rotational axis 26 which is fixed to the housing in the housing 12 to. The axis of rotation 26 is to be understood here as a geometric axis. During the orbital movement about the axis of rotation 26, the two pistons 22 and 24 perform reciprocating movements in opposite directions to one another, wherein these movements in the exemplary embodiment according to FIGS. 1 to 3 are executed as pivoting movements. The pivoting movements of the two pistons 22 and 24 take place about a pivot axis 28 which is perpendicular to the axis of rotation 26 and rotates with the piston 22 and 24 in a horizontal plane about the axis of rotation 26 with.

The pistons 22 and 24 have mutually facing end surfaces 30 and 32 which define a working chamber 36 together with a piston cage 34a, 34b circulating together around the pistons 22 and 24. The axis of rotation 26 passes through the working chamber 36, in the middle. In the working chamber 36 find, mediated by the reciprocating pivotal movements of the pistons 22 and 24, the working cycles of the intake, compression, expansion and ejection take place.

To derive the reciprocating pivotal movements of the pistons 22 and 24 from their orbital motion about the axis of rotation 26, a control mechanism is provided which has a housing fixed cam 38 which is formed on a cam member 40 which is fixed in the housing 12, here on the central housing part 16. The two pistons 22 and 24 are each a running member 42, 44 assigned, wherein the running members 42 and 44 are formed as attached to the respective piston 22 and 24 roller. The running members 42 and 44 are arranged on the end faces 30 and 32 facing away from the rear sides of the pistons 22 and 24.

The pistons 22 and 24 are concentric with the pivot axis 28 arcuately curved and have in cross-section perpendicular to the direction of movement of the pistons 22, 24 a circular cross-section. Accordingly, respective seals 46 and 48 of pistons 22 and 24 for sealing the working chamber 36 are circular seals.

On the axis of rotation 26, a vertically extending shaft 50 is arranged, which extends below the pistons 22 and 24. The shaft 50 is guided out of the housing 12 at its lower end, wherein the cutting blade 11 is rotatably connected to the shaft 50.

The shaft 50 is fixedly connected to the piston cage 34a, 34b, wherein here advantageously the shaft 50 is formed integrally with the lower part 34b of the piston cage 34a, 34b. The shaft 50 is led out of the housing 12 at the bottom. While the shaft 50 is integrally formed here, it may also be multi-piece or multi-part. The shaft 50 and the piston cage 34a, 34b are mounted on the central housing part 16 via a bearing 52.

As is apparent from FIGS. 2 and 3, the axis of rotation 26 passes centrally through the working chamber 36.

With the shaft 50, a cable reel 56 is connected via a coupling 54, on which a rope 58 is wound, which is known for starting the internal combustion engine 10 by Zugausübung by a handle 60 as in lawn mowers known actuated.

Adjacent to the working chamber 36, an inlet port 62 for introducing combustion air and fuel into the working chamber 36, an outlet port 64 for discharging combusted fuel-air mixture from the working chamber 36 and a spark plug 66 are disposed on the top of the housing 12.

For cooling the interior of the housing 12, the housing 12 has on its outside a plurality of cooling ribs 68.

As is apparent from a comparison of Figs. 2 and 3, the control cam 38 on the curve piece 40 on a curve which has wave crests and wave troughs in the vertical direction, and with respect to the rotation axis 26 concave and convex portions to the back and forth swinging movements of the pistons 22 and 24 derived from the orbital motion about the axis of rotation 26.

While FIG. 2 shows the two pistons 22 and 24 in their TDC position, in which the volume of the working chamber 36 is minimal, FIG. 3 shows the two pistons 22 and 24 in their UT position, in which the volume of the working chamber 36 is maximum. Upon a rotation of the two pistons 22 and 24 about the axis of rotation 26 by about 90 °, the pistons 22 and 24 move from the TDC position shown in Fig. 2 in the UT position shown in Fig. 3, and in another cycle around the axis of rotation 26 by 90 ° reach the piston 22 and 24 again the TDC position, etc. At a full Circulation 360 ° about the axis of rotation 26 thus takes place a full cycle of intake, compression, expansion and expulsion.

As is apparent from Fig. 1 to 3, the internal combustion engine 10 is designed as a portal engine, with overhead arranged piston 22 and 24 and underlying and vertically extending drive / output shaft 50. The internal combustion engine 10 may in the case of use in a lawnmower on a chassis plate 70 (omitted in Fig. 1) are mounted.

In Fig. 4 and 5, a further exemplary embodiment of an internal combustion engine 10 'is shown. In the internal combustion engine 10 ', those features that are the same or comparable to those of the internal combustion engine 10, with the same reference numerals as in FIGS. 1 to 3 are provided with a superscript. Hereinafter, only the differences of the internal combustion engine 10 'to the internal combustion engine 10 will be described.

In contrast to the pistons 22 and 24 of the internal combustion engine 10, the pistons 22 'and 24' of the internal combustion engine 10 'are designed as linearly movable pistons which, when rotating around the rotational axis 26', execute reciprocating linear movements directed obliquely to the rotational axis 26 ' , These linear movements are V-shaped obliquely directed to the axis of rotation 26 ', wherein the TDC position of the piston 22', 24 'shown in FIG. 4, the upper position of the piston 22' and 24 ', from which the piston 22' , 24 'move obliquely downwards into the BDC position according to FIG. 5.

The control cam 38 'of the cam member 40' is similar to the control cam 38 of the cam member 40 of the engine 10 in the vertical direction with wave crests and troughs and with respect to the axis of rotation 26 'provided with concave and convex portions. In Fig. 6, finally, yet another embodiment of an internal combustion engine 10 "is shown, which can also be used for a working device, such as a lawnmower.

In the internal combustion engine 10 "are those features that are the same or comparable to those of the internal combustion engine 10, with the same reference numerals, supplemented by" provided.

From the internal combustion engine 10 ", only the differences from the internal combustion engine 10 will be described below.

As with the internal combustion engine 10 ', the two pistons 22 "and 24" when circulating about the axis of rotation 26 "perform linear movements, the linear movements of the pistons 22" and 24 "being directed perpendicular to the axis of rotation 26". As a result, the internal combustion engine 10 "can be made very flat.

The control cam 38 "of the cam member 40" of the internal combustion engine 10 "extends horizontally and is elliptical in order to derive the reciprocating linear movements of the piston 22" and 24 "from the rotational movement about the axis of rotation 26".

In Fig. 7, in addition to the cutting blade 11, a chassis 76 of a lawn mower is shown schematically.

Claims

claims

1. Internal combustion engine, in particular for a working device, with a housing in which a total of a first and a second piston (22, 24, 22 ', 24', 22 ", 24") are arranged, which between their mutually facing end faces a working chamber (36, 36 ', 36 "), wherein the pistons (22, 24, 22', 24 ', 22", 24 ") are arranged about an axis of rotation (26; 26'; 26") in the housing (12, 12 '; 12' ') and thereby perform mutually opposite reciprocating movements, wherein the rotation axis (26; 26'; 26 ") through the working chamber (36; 36 '; 36") extends, and wherein the axis of rotation (26 ; 26 '; 26 ") is substantially vertical in the state of the internal combustion engine (10; 10'; 10") installed in the implement and the pistons (22,24; 22 ', 24'; 22 ", 24") are substantially recumbent and wherein on the axis of rotation (26; 26 '; 26 ") a shaft (50; 50'; 50") non-rotatably connected to the pistons (22, 24; 22 ', 24'; 22 ", 24") arranged below the pistons (22, 24, 22 ', 24', 22 ", 2 4 ") out of the housing (12; 12 '; 12 ") is led out down.

2. Internal combustion engine according to claim 1, wherein the pistons (22, 24, 22 ', 24', 22 ", 24") when revolving about the axis of rotation (26, 26 ', 26 ") oscillate about a pivot axis (FIG. 28; 28 '; 28 ") which is perpendicular to the axis of rotation (26; 26'; 26") and connected to the pistons (22, 24; 22 ', 24'; 22 ", 24") about the axis of rotation (26 ; 26 '; 26 ").

3. Internal combustion engine according to claim 2, wherein the pistons (22, 24, 22 ', 24', 22 ", 24") arcuate with the pivot axis (28, 28 ', 28 ") are formed substantially concentric curvature.

4. Internal combustion engine according to claim 1, wherein the pistons (22, 24, 22 ', 24', 22 ", 24") when running around the axis of rotation (26; 26 '; 26 ") perform linear movements that obliquely V-shaped are directed to the axis of rotation (26; 26 '; 26 ").

5. Internal combustion engine according to claim 1, wherein the pistons (22, 24, 22 ', 24', 22 ", 24"), when circulating about the axis of rotation (26; 26 '; 26 "), execute linear movements which are perpendicular to the axis of rotation (FIG. 26, 26 ', 26 ") are directed.

6. Internal combustion engine according to any one of claims 1 to 5, wherein the pistons (22, 24, 22 ', 24', 22 ", 24") are circular or oval in cross-section perpendicular to their direction of movement.

7. Internal combustion engine according to one of claims 1 to 6, wherein for deriving the reciprocating movement of the piston (22, 24, 22 ', 24', 22 ", 24") from the orbital motion about the axis of rotation (26; 26 ' A control mechanism is provided which comprises a control cam (38, 38 ', 38 ") extending around the axis of rotation (26; 26'; 26"), in each of which at least one on each piston (22, 24; 22 ', 24', 22 ", 24") on which the working chamber (36; 36 ', 36 ") facing away from running member (42, 44, 42', 44 ', 42", 44 ") runs.

8. Internal combustion engine according to one of claims 1 to 7, wherein on one of the working chamber (36; 36 '; 36 ") facing side of the housing (12; 12'; 12") at least one inlet for air and / or fuel, an outlet is arranged for combusted fuel-air mixture and optionally a spark plug.

The use of an internal combustion engine (10; 10 '; 10 ") according to any one of claims 1 to 8 for driving a cutting blade (11; 11'; 11") of a lawn mower.

10. Use of an internal combustion engine (10, 10 ', 10' ') according to one of claims 1 to 8 for driving a cutting element of a brushcutter.

11. Tool, in particular lawn mower or brushcutter, with an internal combustion engine (10, 10 ', 10 ") according to one of claims 1 to 8.